From 9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 Mon Sep 17 00:00:00 2001 From: Yunhong Jiang Date: Tue, 4 Aug 2015 12:17:53 -0700 Subject: Add the rt linux 4.1.3-rt3 as base Import the rt linux 4.1.3-rt3 as OPNFV kvm base. It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and the base is: commit 0917f823c59692d751951bf5ea699a2d1e2f26a2 Author: Sebastian Andrzej Siewior Date: Sat Jul 25 12:13:34 2015 +0200 Prepare v4.1.3-rt3 Signed-off-by: Sebastian Andrzej Siewior We lose all the git history this way and it's not good. We should apply another opnfv project repo in future. Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423 Signed-off-by: Yunhong Jiang --- kernel/ipc/Makefile | 12 + kernel/ipc/compat.c | 757 ++++++++++++++++ kernel/ipc/compat_mq.c | 138 +++ kernel/ipc/ipc_sysctl.c | 224 +++++ kernel/ipc/mq_sysctl.c | 124 +++ kernel/ipc/mqueue.c | 1474 +++++++++++++++++++++++++++++++ kernel/ipc/msg.c | 1060 +++++++++++++++++++++++ kernel/ipc/msgutil.c | 185 ++++ kernel/ipc/namespace.c | 175 ++++ kernel/ipc/sem.c | 2198 +++++++++++++++++++++++++++++++++++++++++++++++ kernel/ipc/shm.c | 1368 +++++++++++++++++++++++++++++ kernel/ipc/syscall.c | 99 +++ kernel/ipc/util.c | 883 +++++++++++++++++++ kernel/ipc/util.h | 207 +++++ 14 files changed, 8904 insertions(+) create mode 100644 kernel/ipc/Makefile create mode 100644 kernel/ipc/compat.c create mode 100644 kernel/ipc/compat_mq.c create mode 100644 kernel/ipc/ipc_sysctl.c create mode 100644 kernel/ipc/mq_sysctl.c create mode 100644 kernel/ipc/mqueue.c create mode 100644 kernel/ipc/msg.c create mode 100644 kernel/ipc/msgutil.c create mode 100644 kernel/ipc/namespace.c create mode 100644 kernel/ipc/sem.c create mode 100644 kernel/ipc/shm.c create mode 100644 kernel/ipc/syscall.c create mode 100644 kernel/ipc/util.c create mode 100644 kernel/ipc/util.h (limited to 'kernel/ipc') diff --git a/kernel/ipc/Makefile b/kernel/ipc/Makefile new file mode 100644 index 000000000..86c7300ec --- /dev/null +++ b/kernel/ipc/Makefile @@ -0,0 +1,12 @@ +# +# Makefile for the linux ipc. +# + +obj-$(CONFIG_SYSVIPC_COMPAT) += compat.o +obj-$(CONFIG_SYSVIPC) += util.o msgutil.o msg.o sem.o shm.o syscall.o +obj-$(CONFIG_SYSVIPC_SYSCTL) += ipc_sysctl.o +obj_mq-$(CONFIG_COMPAT) += compat_mq.o +obj-$(CONFIG_POSIX_MQUEUE) += mqueue.o msgutil.o $(obj_mq-y) +obj-$(CONFIG_IPC_NS) += namespace.o +obj-$(CONFIG_POSIX_MQUEUE_SYSCTL) += mq_sysctl.o + diff --git a/kernel/ipc/compat.c b/kernel/ipc/compat.c new file mode 100644 index 000000000..9b3c85f8a --- /dev/null +++ b/kernel/ipc/compat.c @@ -0,0 +1,757 @@ +/* + * 32 bit compatibility code for System V IPC + * + * Copyright (C) 1997,1998 Jakub Jelinek (jj@sunsite.mff.cuni.cz) + * Copyright (C) 1997 David S. Miller (davem@caip.rutgers.edu) + * Copyright (C) 1999 Arun Sharma + * Copyright (C) 2000 VA Linux Co + * Copyright (C) 2000 Don Dugger + * Copyright (C) 2000 Hewlett-Packard Co. + * Copyright (C) 2000 David Mosberger-Tang + * Copyright (C) 2000 Gerhard Tonn (ton@de.ibm.com) + * Copyright (C) 2000-2002 Andi Kleen, SuSE Labs (x86-64 port) + * Copyright (C) 2000 Silicon Graphics, Inc. + * Copyright (C) 2001 IBM + * Copyright (C) 2004 IBM Deutschland Entwicklung GmbH, IBM Corporation + * Copyright (C) 2004 Arnd Bergmann (arnd@arndb.de) + * + * This code is collected from the versions for sparc64, mips64, s390x, ia64, + * ppc64 and x86_64, all of which are based on the original sparc64 version + * by Jakub Jelinek. + * + */ +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include + +#include "util.h" + +struct compat_msgbuf { + compat_long_t mtype; + char mtext[1]; +}; + +struct compat_ipc_perm { + key_t key; + __compat_uid_t uid; + __compat_gid_t gid; + __compat_uid_t cuid; + __compat_gid_t cgid; + compat_mode_t mode; + unsigned short seq; +}; + +struct compat_semid_ds { + struct compat_ipc_perm sem_perm; + compat_time_t sem_otime; + compat_time_t sem_ctime; + compat_uptr_t sem_base; + compat_uptr_t sem_pending; + compat_uptr_t sem_pending_last; + compat_uptr_t undo; + unsigned short sem_nsems; +}; + +struct compat_msqid_ds { + struct compat_ipc_perm msg_perm; + compat_uptr_t msg_first; + compat_uptr_t msg_last; + compat_time_t msg_stime; + compat_time_t msg_rtime; + compat_time_t msg_ctime; + compat_ulong_t msg_lcbytes; + compat_ulong_t msg_lqbytes; + unsigned short msg_cbytes; + unsigned short msg_qnum; + unsigned short msg_qbytes; + compat_ipc_pid_t msg_lspid; + compat_ipc_pid_t msg_lrpid; +}; + +struct compat_shmid_ds { + struct compat_ipc_perm shm_perm; + int shm_segsz; + compat_time_t shm_atime; + compat_time_t shm_dtime; + compat_time_t shm_ctime; + compat_ipc_pid_t shm_cpid; + compat_ipc_pid_t shm_lpid; + unsigned short shm_nattch; + unsigned short shm_unused; + compat_uptr_t shm_unused2; + compat_uptr_t shm_unused3; +}; + +struct compat_ipc_kludge { + compat_uptr_t msgp; + compat_long_t msgtyp; +}; + +struct compat_shminfo64 { + compat_ulong_t shmmax; + compat_ulong_t shmmin; + compat_ulong_t shmmni; + compat_ulong_t shmseg; + compat_ulong_t shmall; + compat_ulong_t __unused1; + compat_ulong_t __unused2; + compat_ulong_t __unused3; + compat_ulong_t __unused4; +}; + +struct compat_shm_info { + compat_int_t used_ids; + compat_ulong_t shm_tot, shm_rss, shm_swp; + compat_ulong_t swap_attempts, swap_successes; +}; + +static inline int compat_ipc_parse_version(int *cmd) +{ +#ifdef CONFIG_ARCH_WANT_COMPAT_IPC_PARSE_VERSION + int version = *cmd & IPC_64; + + /* this is tricky: architectures that have support for the old + * ipc structures in 64 bit binaries need to have IPC_64 set + * in cmd, the others need to have it cleared */ +#ifndef ipc_parse_version + *cmd |= IPC_64; +#else + *cmd &= ~IPC_64; +#endif + return version; +#else + /* With the asm-generic APIs, we always use the 64-bit versions. */ + return IPC_64; +#endif +} + +static inline int __get_compat_ipc64_perm(struct ipc64_perm *p64, + struct compat_ipc64_perm __user *up64) +{ + int err; + + err = __get_user(p64->uid, &up64->uid); + err |= __get_user(p64->gid, &up64->gid); + err |= __get_user(p64->mode, &up64->mode); + return err; +} + +static inline int __get_compat_ipc_perm(struct ipc64_perm *p, + struct compat_ipc_perm __user *up) +{ + int err; + + err = __get_user(p->uid, &up->uid); + err |= __get_user(p->gid, &up->gid); + err |= __get_user(p->mode, &up->mode); + return err; +} + +static inline int __put_compat_ipc64_perm(struct ipc64_perm *p64, + struct compat_ipc64_perm __user *up64) +{ + int err; + + err = __put_user(p64->key, &up64->key); + err |= __put_user(p64->uid, &up64->uid); + err |= __put_user(p64->gid, &up64->gid); + err |= __put_user(p64->cuid, &up64->cuid); + err |= __put_user(p64->cgid, &up64->cgid); + err |= __put_user(p64->mode, &up64->mode); + err |= __put_user(p64->seq, &up64->seq); + return err; +} + +static inline int __put_compat_ipc_perm(struct ipc64_perm *p, + struct compat_ipc_perm __user *uip) +{ + int err; + __compat_uid_t u; + __compat_gid_t g; + + err = __put_user(p->key, &uip->key); + SET_UID(u, p->uid); + err |= __put_user(u, &uip->uid); + SET_GID(g, p->gid); + err |= __put_user(g, &uip->gid); + SET_UID(u, p->cuid); + err |= __put_user(u, &uip->cuid); + SET_GID(g, p->cgid); + err |= __put_user(g, &uip->cgid); + err |= __put_user(p->mode, &uip->mode); + err |= __put_user(p->seq, &uip->seq); + return err; +} + +static inline int get_compat_semid64_ds(struct semid64_ds *sem64, + struct compat_semid64_ds __user *up64) +{ + if (!access_ok(VERIFY_READ, up64, sizeof(*up64))) + return -EFAULT; + return __get_compat_ipc64_perm(&sem64->sem_perm, &up64->sem_perm); +} + +static inline int get_compat_semid_ds(struct semid64_ds *s, + struct compat_semid_ds __user *up) +{ + if (!access_ok(VERIFY_READ, up, sizeof(*up))) + return -EFAULT; + return __get_compat_ipc_perm(&s->sem_perm, &up->sem_perm); +} + +static inline int put_compat_semid64_ds(struct semid64_ds *sem64, + struct compat_semid64_ds __user *up64) +{ + int err; + + if (!access_ok(VERIFY_WRITE, up64, sizeof(*up64))) + return -EFAULT; + err = __put_compat_ipc64_perm(&sem64->sem_perm, &up64->sem_perm); + err |= __put_user(sem64->sem_otime, &up64->sem_otime); + err |= __put_user(sem64->sem_ctime, &up64->sem_ctime); + err |= __put_user(sem64->sem_nsems, &up64->sem_nsems); + return err; +} + +static inline int put_compat_semid_ds(struct semid64_ds *s, + struct compat_semid_ds __user *up) +{ + int err; + + if (!access_ok(VERIFY_WRITE, up, sizeof(*up))) + return -EFAULT; + err = __put_compat_ipc_perm(&s->sem_perm, &up->sem_perm); + err |= __put_user(s->sem_otime, &up->sem_otime); + err |= __put_user(s->sem_ctime, &up->sem_ctime); + err |= __put_user(s->sem_nsems, &up->sem_nsems); + return err; +} + +static long do_compat_semctl(int first, int second, int third, u32 pad) +{ + unsigned long fourth; + int err, err2; + struct semid64_ds sem64; + struct semid64_ds __user *up64; + int version = compat_ipc_parse_version(&third); + + memset(&sem64, 0, sizeof(sem64)); + + if ((third & (~IPC_64)) == SETVAL) +#ifdef __BIG_ENDIAN + fourth = (unsigned long)pad << 32; +#else + fourth = pad; +#endif + else + fourth = (unsigned long)compat_ptr(pad); + switch (third & (~IPC_64)) { + case IPC_INFO: + case IPC_RMID: + case SEM_INFO: + case GETVAL: + case GETPID: + case GETNCNT: + case GETZCNT: + case GETALL: + case SETVAL: + case SETALL: + err = sys_semctl(first, second, third, fourth); + break; + + case IPC_STAT: + case SEM_STAT: + up64 = compat_alloc_user_space(sizeof(sem64)); + fourth = (unsigned long)up64; + err = sys_semctl(first, second, third, fourth); + if (err < 0) + break; + if (copy_from_user(&sem64, up64, sizeof(sem64))) + err2 = -EFAULT; + else if (version == IPC_64) + err2 = put_compat_semid64_ds(&sem64, compat_ptr(pad)); + else + err2 = put_compat_semid_ds(&sem64, compat_ptr(pad)); + if (err2) + err = -EFAULT; + break; + + case IPC_SET: + if (version == IPC_64) + err = get_compat_semid64_ds(&sem64, compat_ptr(pad)); + else + err = get_compat_semid_ds(&sem64, compat_ptr(pad)); + + up64 = compat_alloc_user_space(sizeof(sem64)); + if (copy_to_user(up64, &sem64, sizeof(sem64))) + err = -EFAULT; + if (err) + break; + + fourth = (unsigned long)up64; + err = sys_semctl(first, second, third, fourth); + break; + + default: + err = -EINVAL; + break; + } + return err; +} + +static long compat_do_msg_fill(void __user *dest, struct msg_msg *msg, size_t bufsz) +{ + struct compat_msgbuf __user *msgp = dest; + size_t msgsz; + + if (put_user(msg->m_type, &msgp->mtype)) + return -EFAULT; + + msgsz = (bufsz > msg->m_ts) ? msg->m_ts : bufsz; + if (store_msg(msgp->mtext, msg, msgsz)) + return -EFAULT; + return msgsz; +} + +#ifndef COMPAT_SHMLBA +#define COMPAT_SHMLBA SHMLBA +#endif + +#ifdef CONFIG_ARCH_WANT_OLD_COMPAT_IPC +COMPAT_SYSCALL_DEFINE6(ipc, u32, call, int, first, int, second, + u32, third, compat_uptr_t, ptr, u32, fifth) +{ + int version; + u32 pad; + + version = call >> 16; /* hack for backward compatibility */ + call &= 0xffff; + + switch (call) { + case SEMOP: + /* struct sembuf is the same on 32 and 64bit :)) */ + return sys_semtimedop(first, compat_ptr(ptr), second, NULL); + case SEMTIMEDOP: + return compat_sys_semtimedop(first, compat_ptr(ptr), second, + compat_ptr(fifth)); + case SEMGET: + return sys_semget(first, second, third); + case SEMCTL: + if (!ptr) + return -EINVAL; + if (get_user(pad, (u32 __user *) compat_ptr(ptr))) + return -EFAULT; + return do_compat_semctl(first, second, third, pad); + + case MSGSND: { + struct compat_msgbuf __user *up = compat_ptr(ptr); + compat_long_t type; + + if (first < 0 || second < 0) + return -EINVAL; + + if (get_user(type, &up->mtype)) + return -EFAULT; + + return do_msgsnd(first, type, up->mtext, second, third); + } + case MSGRCV: { + void __user *uptr = compat_ptr(ptr); + + if (first < 0 || second < 0) + return -EINVAL; + + if (!version) { + struct compat_ipc_kludge ipck; + if (!uptr) + return -EINVAL; + if (copy_from_user(&ipck, uptr, sizeof(ipck))) + return -EFAULT; + uptr = compat_ptr(ipck.msgp); + fifth = ipck.msgtyp; + } + return do_msgrcv(first, uptr, second, (s32)fifth, third, + compat_do_msg_fill); + } + case MSGGET: + return sys_msgget(first, second); + case MSGCTL: + return compat_sys_msgctl(first, second, compat_ptr(ptr)); + + case SHMAT: { + int err; + unsigned long raddr; + + if (version == 1) + return -EINVAL; + err = do_shmat(first, compat_ptr(ptr), second, &raddr, + COMPAT_SHMLBA); + if (err < 0) + return err; + return put_user(raddr, (compat_ulong_t *)compat_ptr(third)); + } + case SHMDT: + return sys_shmdt(compat_ptr(ptr)); + case SHMGET: + return sys_shmget(first, (unsigned)second, third); + case SHMCTL: + return compat_sys_shmctl(first, second, compat_ptr(ptr)); + } + + return -ENOSYS; +} +#endif + +COMPAT_SYSCALL_DEFINE4(semctl, int, semid, int, semnum, int, cmd, int, arg) +{ + return do_compat_semctl(semid, semnum, cmd, arg); +} + +COMPAT_SYSCALL_DEFINE4(msgsnd, int, msqid, compat_uptr_t, msgp, + compat_ssize_t, msgsz, int, msgflg) +{ + struct compat_msgbuf __user *up = compat_ptr(msgp); + compat_long_t mtype; + + if (get_user(mtype, &up->mtype)) + return -EFAULT; + return do_msgsnd(msqid, mtype, up->mtext, (ssize_t)msgsz, msgflg); +} + +COMPAT_SYSCALL_DEFINE5(msgrcv, int, msqid, compat_uptr_t, msgp, + compat_ssize_t, msgsz, compat_long_t, msgtyp, int, msgflg) +{ + return do_msgrcv(msqid, compat_ptr(msgp), (ssize_t)msgsz, (long)msgtyp, + msgflg, compat_do_msg_fill); +} + +static inline int get_compat_msqid64(struct msqid64_ds *m64, + struct compat_msqid64_ds __user *up64) +{ + int err; + + if (!access_ok(VERIFY_READ, up64, sizeof(*up64))) + return -EFAULT; + err = __get_compat_ipc64_perm(&m64->msg_perm, &up64->msg_perm); + err |= __get_user(m64->msg_qbytes, &up64->msg_qbytes); + return err; +} + +static inline int get_compat_msqid(struct msqid64_ds *m, + struct compat_msqid_ds __user *up) +{ + int err; + + if (!access_ok(VERIFY_READ, up, sizeof(*up))) + return -EFAULT; + err = __get_compat_ipc_perm(&m->msg_perm, &up->msg_perm); + err |= __get_user(m->msg_qbytes, &up->msg_qbytes); + return err; +} + +static inline int put_compat_msqid64_ds(struct msqid64_ds *m64, + struct compat_msqid64_ds __user *up64) +{ + int err; + + if (!access_ok(VERIFY_WRITE, up64, sizeof(*up64))) + return -EFAULT; + err = __put_compat_ipc64_perm(&m64->msg_perm, &up64->msg_perm); + err |= __put_user(m64->msg_stime, &up64->msg_stime); + err |= __put_user(m64->msg_rtime, &up64->msg_rtime); + err |= __put_user(m64->msg_ctime, &up64->msg_ctime); + err |= __put_user(m64->msg_cbytes, &up64->msg_cbytes); + err |= __put_user(m64->msg_qnum, &up64->msg_qnum); + err |= __put_user(m64->msg_qbytes, &up64->msg_qbytes); + err |= __put_user(m64->msg_lspid, &up64->msg_lspid); + err |= __put_user(m64->msg_lrpid, &up64->msg_lrpid); + return err; +} + +static inline int put_compat_msqid_ds(struct msqid64_ds *m, + struct compat_msqid_ds __user *up) +{ + int err; + + if (!access_ok(VERIFY_WRITE, up, sizeof(*up))) + return -EFAULT; + err = __put_compat_ipc_perm(&m->msg_perm, &up->msg_perm); + err |= __put_user(m->msg_stime, &up->msg_stime); + err |= __put_user(m->msg_rtime, &up->msg_rtime); + err |= __put_user(m->msg_ctime, &up->msg_ctime); + err |= __put_user(m->msg_cbytes, &up->msg_cbytes); + err |= __put_user(m->msg_qnum, &up->msg_qnum); + err |= __put_user(m->msg_qbytes, &up->msg_qbytes); + err |= __put_user(m->msg_lspid, &up->msg_lspid); + err |= __put_user(m->msg_lrpid, &up->msg_lrpid); + return err; +} + +COMPAT_SYSCALL_DEFINE3(msgctl, int, first, int, second, void __user *, uptr) +{ + int err, err2; + struct msqid64_ds m64; + int version = compat_ipc_parse_version(&second); + void __user *p; + + memset(&m64, 0, sizeof(m64)); + + switch (second & (~IPC_64)) { + case IPC_INFO: + case IPC_RMID: + case MSG_INFO: + err = sys_msgctl(first, second, uptr); + break; + + case IPC_SET: + if (version == IPC_64) + err = get_compat_msqid64(&m64, uptr); + else + err = get_compat_msqid(&m64, uptr); + + if (err) + break; + p = compat_alloc_user_space(sizeof(m64)); + if (copy_to_user(p, &m64, sizeof(m64))) + err = -EFAULT; + else + err = sys_msgctl(first, second, p); + break; + + case IPC_STAT: + case MSG_STAT: + p = compat_alloc_user_space(sizeof(m64)); + err = sys_msgctl(first, second, p); + if (err < 0) + break; + if (copy_from_user(&m64, p, sizeof(m64))) + err2 = -EFAULT; + else if (version == IPC_64) + err2 = put_compat_msqid64_ds(&m64, uptr); + else + err2 = put_compat_msqid_ds(&m64, uptr); + if (err2) + err = -EFAULT; + break; + + default: + err = -EINVAL; + break; + } + return err; +} + +COMPAT_SYSCALL_DEFINE3(shmat, int, shmid, compat_uptr_t, shmaddr, int, shmflg) +{ + unsigned long ret; + long err; + + err = do_shmat(shmid, compat_ptr(shmaddr), shmflg, &ret, COMPAT_SHMLBA); + if (err) + return err; + force_successful_syscall_return(); + return (long)ret; +} + +static inline int get_compat_shmid64_ds(struct shmid64_ds *sem64, + struct compat_shmid64_ds __user *up64) +{ + if (!access_ok(VERIFY_READ, up64, sizeof(*up64))) + return -EFAULT; + return __get_compat_ipc64_perm(&sem64->shm_perm, &up64->shm_perm); +} + +static inline int get_compat_shmid_ds(struct shmid64_ds *s, + struct compat_shmid_ds __user *up) +{ + if (!access_ok(VERIFY_READ, up, sizeof(*up))) + return -EFAULT; + return __get_compat_ipc_perm(&s->shm_perm, &up->shm_perm); +} + +static inline int put_compat_shmid64_ds(struct shmid64_ds *sem64, + struct compat_shmid64_ds __user *up64) +{ + int err; + + if (!access_ok(VERIFY_WRITE, up64, sizeof(*up64))) + return -EFAULT; + err = __put_compat_ipc64_perm(&sem64->shm_perm, &up64->shm_perm); + err |= __put_user(sem64->shm_atime, &up64->shm_atime); + err |= __put_user(sem64->shm_dtime, &up64->shm_dtime); + err |= __put_user(sem64->shm_ctime, &up64->shm_ctime); + err |= __put_user(sem64->shm_segsz, &up64->shm_segsz); + err |= __put_user(sem64->shm_nattch, &up64->shm_nattch); + err |= __put_user(sem64->shm_cpid, &up64->shm_cpid); + err |= __put_user(sem64->shm_lpid, &up64->shm_lpid); + return err; +} + +static inline int put_compat_shmid_ds(struct shmid64_ds *s, + struct compat_shmid_ds __user *up) +{ + int err; + + if (!access_ok(VERIFY_WRITE, up, sizeof(*up))) + return -EFAULT; + err = __put_compat_ipc_perm(&s->shm_perm, &up->shm_perm); + err |= __put_user(s->shm_atime, &up->shm_atime); + err |= __put_user(s->shm_dtime, &up->shm_dtime); + err |= __put_user(s->shm_ctime, &up->shm_ctime); + err |= __put_user(s->shm_segsz, &up->shm_segsz); + err |= __put_user(s->shm_nattch, &up->shm_nattch); + err |= __put_user(s->shm_cpid, &up->shm_cpid); + err |= __put_user(s->shm_lpid, &up->shm_lpid); + return err; +} + +static inline int put_compat_shminfo64(struct shminfo64 *smi, + struct compat_shminfo64 __user *up64) +{ + int err; + + if (!access_ok(VERIFY_WRITE, up64, sizeof(*up64))) + return -EFAULT; + if (smi->shmmax > INT_MAX) + smi->shmmax = INT_MAX; + err = __put_user(smi->shmmax, &up64->shmmax); + err |= __put_user(smi->shmmin, &up64->shmmin); + err |= __put_user(smi->shmmni, &up64->shmmni); + err |= __put_user(smi->shmseg, &up64->shmseg); + err |= __put_user(smi->shmall, &up64->shmall); + return err; +} + +static inline int put_compat_shminfo(struct shminfo64 *smi, + struct shminfo __user *up) +{ + int err; + + if (!access_ok(VERIFY_WRITE, up, sizeof(*up))) + return -EFAULT; + if (smi->shmmax > INT_MAX) + smi->shmmax = INT_MAX; + err = __put_user(smi->shmmax, &up->shmmax); + err |= __put_user(smi->shmmin, &up->shmmin); + err |= __put_user(smi->shmmni, &up->shmmni); + err |= __put_user(smi->shmseg, &up->shmseg); + err |= __put_user(smi->shmall, &up->shmall); + return err; +} + +static inline int put_compat_shm_info(struct shm_info __user *ip, + struct compat_shm_info __user *uip) +{ + int err; + struct shm_info si; + + if (!access_ok(VERIFY_WRITE, uip, sizeof(*uip)) || + copy_from_user(&si, ip, sizeof(si))) + return -EFAULT; + err = __put_user(si.used_ids, &uip->used_ids); + err |= __put_user(si.shm_tot, &uip->shm_tot); + err |= __put_user(si.shm_rss, &uip->shm_rss); + err |= __put_user(si.shm_swp, &uip->shm_swp); + err |= __put_user(si.swap_attempts, &uip->swap_attempts); + err |= __put_user(si.swap_successes, &uip->swap_successes); + return err; +} + +COMPAT_SYSCALL_DEFINE3(shmctl, int, first, int, second, void __user *, uptr) +{ + void __user *p; + struct shmid64_ds sem64; + struct shminfo64 smi; + int err, err2; + int version = compat_ipc_parse_version(&second); + + memset(&sem64, 0, sizeof(sem64)); + + switch (second & (~IPC_64)) { + case IPC_RMID: + case SHM_LOCK: + case SHM_UNLOCK: + err = sys_shmctl(first, second, uptr); + break; + + case IPC_INFO: + p = compat_alloc_user_space(sizeof(smi)); + err = sys_shmctl(first, second, p); + if (err < 0) + break; + if (copy_from_user(&smi, p, sizeof(smi))) + err2 = -EFAULT; + else if (version == IPC_64) + err2 = put_compat_shminfo64(&smi, uptr); + else + err2 = put_compat_shminfo(&smi, uptr); + if (err2) + err = -EFAULT; + break; + + + case IPC_SET: + if (version == IPC_64) + err = get_compat_shmid64_ds(&sem64, uptr); + else + err = get_compat_shmid_ds(&sem64, uptr); + + if (err) + break; + p = compat_alloc_user_space(sizeof(sem64)); + if (copy_to_user(p, &sem64, sizeof(sem64))) + err = -EFAULT; + else + err = sys_shmctl(first, second, p); + break; + + case IPC_STAT: + case SHM_STAT: + p = compat_alloc_user_space(sizeof(sem64)); + err = sys_shmctl(first, second, p); + if (err < 0) + break; + if (copy_from_user(&sem64, p, sizeof(sem64))) + err2 = -EFAULT; + else if (version == IPC_64) + err2 = put_compat_shmid64_ds(&sem64, uptr); + else + err2 = put_compat_shmid_ds(&sem64, uptr); + if (err2) + err = -EFAULT; + break; + + case SHM_INFO: + p = compat_alloc_user_space(sizeof(struct shm_info)); + err = sys_shmctl(first, second, p); + if (err < 0) + break; + err2 = put_compat_shm_info(p, uptr); + if (err2) + err = -EFAULT; + break; + + default: + err = -EINVAL; + break; + } + return err; +} + +COMPAT_SYSCALL_DEFINE4(semtimedop, int, semid, struct sembuf __user *, tsems, + unsigned, nsops, + const struct compat_timespec __user *, timeout) +{ + struct timespec __user *ts64; + if (compat_convert_timespec(&ts64, timeout)) + return -EFAULT; + return sys_semtimedop(semid, tsems, nsops, ts64); +} diff --git a/kernel/ipc/compat_mq.c b/kernel/ipc/compat_mq.c new file mode 100644 index 000000000..ef6f91cc4 --- /dev/null +++ b/kernel/ipc/compat_mq.c @@ -0,0 +1,138 @@ +/* + * ipc/compat_mq.c + * 32 bit emulation for POSIX message queue system calls + * + * Copyright (C) 2004 IBM Deutschland Entwicklung GmbH, IBM Corporation + * Author: Arnd Bergmann + */ + +#include +#include +#include +#include +#include + +#include + +struct compat_mq_attr { + compat_long_t mq_flags; /* message queue flags */ + compat_long_t mq_maxmsg; /* maximum number of messages */ + compat_long_t mq_msgsize; /* maximum message size */ + compat_long_t mq_curmsgs; /* number of messages currently queued */ + compat_long_t __reserved[4]; /* ignored for input, zeroed for output */ +}; + +static inline int get_compat_mq_attr(struct mq_attr *attr, + const struct compat_mq_attr __user *uattr) +{ + if (!access_ok(VERIFY_READ, uattr, sizeof *uattr)) + return -EFAULT; + + return __get_user(attr->mq_flags, &uattr->mq_flags) + | __get_user(attr->mq_maxmsg, &uattr->mq_maxmsg) + | __get_user(attr->mq_msgsize, &uattr->mq_msgsize) + | __get_user(attr->mq_curmsgs, &uattr->mq_curmsgs); +} + +static inline int put_compat_mq_attr(const struct mq_attr *attr, + struct compat_mq_attr __user *uattr) +{ + if (clear_user(uattr, sizeof *uattr)) + return -EFAULT; + + return __put_user(attr->mq_flags, &uattr->mq_flags) + | __put_user(attr->mq_maxmsg, &uattr->mq_maxmsg) + | __put_user(attr->mq_msgsize, &uattr->mq_msgsize) + | __put_user(attr->mq_curmsgs, &uattr->mq_curmsgs); +} + +COMPAT_SYSCALL_DEFINE4(mq_open, const char __user *, u_name, + int, oflag, compat_mode_t, mode, + struct compat_mq_attr __user *, u_attr) +{ + void __user *p = NULL; + if (u_attr && oflag & O_CREAT) { + struct mq_attr attr; + + memset(&attr, 0, sizeof(attr)); + + p = compat_alloc_user_space(sizeof(attr)); + if (get_compat_mq_attr(&attr, u_attr) || + copy_to_user(p, &attr, sizeof(attr))) + return -EFAULT; + } + return sys_mq_open(u_name, oflag, mode, p); +} + +COMPAT_SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, + const char __user *, u_msg_ptr, + compat_size_t, msg_len, unsigned int, msg_prio, + const struct compat_timespec __user *, u_abs_timeout) +{ + struct timespec __user *u_ts; + + if (compat_convert_timespec(&u_ts, u_abs_timeout)) + return -EFAULT; + + return sys_mq_timedsend(mqdes, u_msg_ptr, msg_len, + msg_prio, u_ts); +} + +COMPAT_SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, + char __user *, u_msg_ptr, + compat_size_t, msg_len, unsigned int __user *, u_msg_prio, + const struct compat_timespec __user *, u_abs_timeout) +{ + struct timespec __user *u_ts; + + if (compat_convert_timespec(&u_ts, u_abs_timeout)) + return -EFAULT; + + return sys_mq_timedreceive(mqdes, u_msg_ptr, msg_len, + u_msg_prio, u_ts); +} + +COMPAT_SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes, + const struct compat_sigevent __user *, u_notification) +{ + struct sigevent __user *p = NULL; + if (u_notification) { + struct sigevent n; + p = compat_alloc_user_space(sizeof(*p)); + if (get_compat_sigevent(&n, u_notification)) + return -EFAULT; + if (n.sigev_notify == SIGEV_THREAD) + n.sigev_value.sival_ptr = compat_ptr(n.sigev_value.sival_int); + if (copy_to_user(p, &n, sizeof(*p))) + return -EFAULT; + } + return sys_mq_notify(mqdes, p); +} + +COMPAT_SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes, + const struct compat_mq_attr __user *, u_mqstat, + struct compat_mq_attr __user *, u_omqstat) +{ + struct mq_attr mqstat; + struct mq_attr __user *p = compat_alloc_user_space(2 * sizeof(*p)); + long ret; + + memset(&mqstat, 0, sizeof(mqstat)); + + if (u_mqstat) { + if (get_compat_mq_attr(&mqstat, u_mqstat) || + copy_to_user(p, &mqstat, sizeof(mqstat))) + return -EFAULT; + } + ret = sys_mq_getsetattr(mqdes, + u_mqstat ? p : NULL, + u_omqstat ? p + 1 : NULL); + if (ret) + return ret; + if (u_omqstat) { + if (copy_from_user(&mqstat, p + 1, sizeof(mqstat)) || + put_compat_mq_attr(&mqstat, u_omqstat)) + return -EFAULT; + } + return 0; +} diff --git a/kernel/ipc/ipc_sysctl.c b/kernel/ipc/ipc_sysctl.c new file mode 100644 index 000000000..8ad93c29f --- /dev/null +++ b/kernel/ipc/ipc_sysctl.c @@ -0,0 +1,224 @@ +/* + * Copyright (C) 2007 + * + * Author: Eric Biederman + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation, version 2 of the + * License. + */ + +#include +#include +#include +#include +#include +#include +#include +#include "util.h" + +static void *get_ipc(struct ctl_table *table) +{ + char *which = table->data; + struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns; + which = (which - (char *)&init_ipc_ns) + (char *)ipc_ns; + return which; +} + +#ifdef CONFIG_PROC_SYSCTL +static int proc_ipc_dointvec(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, loff_t *ppos) +{ + struct ctl_table ipc_table; + + memcpy(&ipc_table, table, sizeof(ipc_table)); + ipc_table.data = get_ipc(table); + + return proc_dointvec(&ipc_table, write, buffer, lenp, ppos); +} + +static int proc_ipc_dointvec_minmax(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, loff_t *ppos) +{ + struct ctl_table ipc_table; + + memcpy(&ipc_table, table, sizeof(ipc_table)); + ipc_table.data = get_ipc(table); + + return proc_dointvec_minmax(&ipc_table, write, buffer, lenp, ppos); +} + +static int proc_ipc_dointvec_minmax_orphans(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, loff_t *ppos) +{ + struct ipc_namespace *ns = current->nsproxy->ipc_ns; + int err = proc_ipc_dointvec_minmax(table, write, buffer, lenp, ppos); + + if (err < 0) + return err; + if (ns->shm_rmid_forced) + shm_destroy_orphaned(ns); + return err; +} + +static int proc_ipc_doulongvec_minmax(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, loff_t *ppos) +{ + struct ctl_table ipc_table; + memcpy(&ipc_table, table, sizeof(ipc_table)); + ipc_table.data = get_ipc(table); + + return proc_doulongvec_minmax(&ipc_table, write, buffer, + lenp, ppos); +} + +static int proc_ipc_auto_msgmni(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, loff_t *ppos) +{ + struct ctl_table ipc_table; + int dummy = 0; + + memcpy(&ipc_table, table, sizeof(ipc_table)); + ipc_table.data = &dummy; + + if (write) + pr_info_once("writing to auto_msgmni has no effect"); + + return proc_dointvec_minmax(&ipc_table, write, buffer, lenp, ppos); +} + +#else +#define proc_ipc_doulongvec_minmax NULL +#define proc_ipc_dointvec NULL +#define proc_ipc_dointvec_minmax NULL +#define proc_ipc_dointvec_minmax_orphans NULL +#define proc_ipc_auto_msgmni NULL +#endif + +static int zero; +static int one = 1; +static int int_max = INT_MAX; + +static struct ctl_table ipc_kern_table[] = { + { + .procname = "shmmax", + .data = &init_ipc_ns.shm_ctlmax, + .maxlen = sizeof(init_ipc_ns.shm_ctlmax), + .mode = 0644, + .proc_handler = proc_ipc_doulongvec_minmax, + }, + { + .procname = "shmall", + .data = &init_ipc_ns.shm_ctlall, + .maxlen = sizeof(init_ipc_ns.shm_ctlall), + .mode = 0644, + .proc_handler = proc_ipc_doulongvec_minmax, + }, + { + .procname = "shmmni", + .data = &init_ipc_ns.shm_ctlmni, + .maxlen = sizeof(init_ipc_ns.shm_ctlmni), + .mode = 0644, + .proc_handler = proc_ipc_dointvec, + }, + { + .procname = "shm_rmid_forced", + .data = &init_ipc_ns.shm_rmid_forced, + .maxlen = sizeof(init_ipc_ns.shm_rmid_forced), + .mode = 0644, + .proc_handler = proc_ipc_dointvec_minmax_orphans, + .extra1 = &zero, + .extra2 = &one, + }, + { + .procname = "msgmax", + .data = &init_ipc_ns.msg_ctlmax, + .maxlen = sizeof(init_ipc_ns.msg_ctlmax), + .mode = 0644, + .proc_handler = proc_ipc_dointvec_minmax, + .extra1 = &zero, + .extra2 = &int_max, + }, + { + .procname = "msgmni", + .data = &init_ipc_ns.msg_ctlmni, + .maxlen = sizeof(init_ipc_ns.msg_ctlmni), + .mode = 0644, + .proc_handler = proc_ipc_dointvec_minmax, + .extra1 = &zero, + .extra2 = &int_max, + }, + { + .procname = "auto_msgmni", + .data = NULL, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_ipc_auto_msgmni, + .extra1 = &zero, + .extra2 = &one, + }, + { + .procname = "msgmnb", + .data = &init_ipc_ns.msg_ctlmnb, + .maxlen = sizeof(init_ipc_ns.msg_ctlmnb), + .mode = 0644, + .proc_handler = proc_ipc_dointvec_minmax, + .extra1 = &zero, + .extra2 = &int_max, + }, + { + .procname = "sem", + .data = &init_ipc_ns.sem_ctls, + .maxlen = 4*sizeof(int), + .mode = 0644, + .proc_handler = proc_ipc_dointvec, + }, +#ifdef CONFIG_CHECKPOINT_RESTORE + { + .procname = "sem_next_id", + .data = &init_ipc_ns.ids[IPC_SEM_IDS].next_id, + .maxlen = sizeof(init_ipc_ns.ids[IPC_SEM_IDS].next_id), + .mode = 0644, + .proc_handler = proc_ipc_dointvec_minmax, + .extra1 = &zero, + .extra2 = &int_max, + }, + { + .procname = "msg_next_id", + .data = &init_ipc_ns.ids[IPC_MSG_IDS].next_id, + .maxlen = sizeof(init_ipc_ns.ids[IPC_MSG_IDS].next_id), + .mode = 0644, + .proc_handler = proc_ipc_dointvec_minmax, + .extra1 = &zero, + .extra2 = &int_max, + }, + { + .procname = "shm_next_id", + .data = &init_ipc_ns.ids[IPC_SHM_IDS].next_id, + .maxlen = sizeof(init_ipc_ns.ids[IPC_SHM_IDS].next_id), + .mode = 0644, + .proc_handler = proc_ipc_dointvec_minmax, + .extra1 = &zero, + .extra2 = &int_max, + }, +#endif + {} +}; + +static struct ctl_table ipc_root_table[] = { + { + .procname = "kernel", + .mode = 0555, + .child = ipc_kern_table, + }, + {} +}; + +static int __init ipc_sysctl_init(void) +{ + register_sysctl_table(ipc_root_table); + return 0; +} + +device_initcall(ipc_sysctl_init); diff --git a/kernel/ipc/mq_sysctl.c b/kernel/ipc/mq_sysctl.c new file mode 100644 index 000000000..68d4e9537 --- /dev/null +++ b/kernel/ipc/mq_sysctl.c @@ -0,0 +1,124 @@ +/* + * Copyright (C) 2007 IBM Corporation + * + * Author: Cedric Le Goater + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation, version 2 of the + * License. + */ + +#include +#include +#include + +#ifdef CONFIG_PROC_SYSCTL +static void *get_mq(struct ctl_table *table) +{ + char *which = table->data; + struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns; + which = (which - (char *)&init_ipc_ns) + (char *)ipc_ns; + return which; +} + +static int proc_mq_dointvec(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, loff_t *ppos) +{ + struct ctl_table mq_table; + memcpy(&mq_table, table, sizeof(mq_table)); + mq_table.data = get_mq(table); + + return proc_dointvec(&mq_table, write, buffer, lenp, ppos); +} + +static int proc_mq_dointvec_minmax(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, loff_t *ppos) +{ + struct ctl_table mq_table; + memcpy(&mq_table, table, sizeof(mq_table)); + mq_table.data = get_mq(table); + + return proc_dointvec_minmax(&mq_table, write, buffer, + lenp, ppos); +} +#else +#define proc_mq_dointvec NULL +#define proc_mq_dointvec_minmax NULL +#endif + +static int msg_max_limit_min = MIN_MSGMAX; +static int msg_max_limit_max = HARD_MSGMAX; + +static int msg_maxsize_limit_min = MIN_MSGSIZEMAX; +static int msg_maxsize_limit_max = HARD_MSGSIZEMAX; + +static struct ctl_table mq_sysctls[] = { + { + .procname = "queues_max", + .data = &init_ipc_ns.mq_queues_max, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_mq_dointvec, + }, + { + .procname = "msg_max", + .data = &init_ipc_ns.mq_msg_max, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_mq_dointvec_minmax, + .extra1 = &msg_max_limit_min, + .extra2 = &msg_max_limit_max, + }, + { + .procname = "msgsize_max", + .data = &init_ipc_ns.mq_msgsize_max, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_mq_dointvec_minmax, + .extra1 = &msg_maxsize_limit_min, + .extra2 = &msg_maxsize_limit_max, + }, + { + .procname = "msg_default", + .data = &init_ipc_ns.mq_msg_default, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_mq_dointvec_minmax, + .extra1 = &msg_max_limit_min, + .extra2 = &msg_max_limit_max, + }, + { + .procname = "msgsize_default", + .data = &init_ipc_ns.mq_msgsize_default, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_mq_dointvec_minmax, + .extra1 = &msg_maxsize_limit_min, + .extra2 = &msg_maxsize_limit_max, + }, + {} +}; + +static struct ctl_table mq_sysctl_dir[] = { + { + .procname = "mqueue", + .mode = 0555, + .child = mq_sysctls, + }, + {} +}; + +static struct ctl_table mq_sysctl_root[] = { + { + .procname = "fs", + .mode = 0555, + .child = mq_sysctl_dir, + }, + {} +}; + +struct ctl_table_header *mq_register_sysctl_table(void) +{ + return register_sysctl_table(mq_sysctl_root); +} diff --git a/kernel/ipc/mqueue.c b/kernel/ipc/mqueue.c new file mode 100644 index 000000000..a24ba9fe5 --- /dev/null +++ b/kernel/ipc/mqueue.c @@ -0,0 +1,1474 @@ +/* + * POSIX message queues filesystem for Linux. + * + * Copyright (C) 2003,2004 Krzysztof Benedyczak (golbi@mat.uni.torun.pl) + * Michal Wronski (michal.wronski@gmail.com) + * + * Spinlocks: Mohamed Abbas (abbas.mohamed@intel.com) + * Lockless receive & send, fd based notify: + * Manfred Spraul (manfred@colorfullife.com) + * + * Audit: George Wilson (ltcgcw@us.ibm.com) + * + * This file is released under the GPL. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include "util.h" + +#define MQUEUE_MAGIC 0x19800202 +#define DIRENT_SIZE 20 +#define FILENT_SIZE 80 + +#define SEND 0 +#define RECV 1 + +#define STATE_NONE 0 +#define STATE_READY 1 + +struct posix_msg_tree_node { + struct rb_node rb_node; + struct list_head msg_list; + int priority; +}; + +struct ext_wait_queue { /* queue of sleeping tasks */ + struct task_struct *task; + struct list_head list; + struct msg_msg *msg; /* ptr of loaded message */ + int state; /* one of STATE_* values */ +}; + +struct mqueue_inode_info { + spinlock_t lock; + struct inode vfs_inode; + wait_queue_head_t wait_q; + + struct rb_root msg_tree; + struct posix_msg_tree_node *node_cache; + struct mq_attr attr; + + struct sigevent notify; + struct pid *notify_owner; + struct user_namespace *notify_user_ns; + struct user_struct *user; /* user who created, for accounting */ + struct sock *notify_sock; + struct sk_buff *notify_cookie; + + /* for tasks waiting for free space and messages, respectively */ + struct ext_wait_queue e_wait_q[2]; + + unsigned long qsize; /* size of queue in memory (sum of all msgs) */ +}; + +static const struct inode_operations mqueue_dir_inode_operations; +static const struct file_operations mqueue_file_operations; +static const struct super_operations mqueue_super_ops; +static void remove_notification(struct mqueue_inode_info *info); + +static struct kmem_cache *mqueue_inode_cachep; + +static struct ctl_table_header *mq_sysctl_table; + +static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode) +{ + return container_of(inode, struct mqueue_inode_info, vfs_inode); +} + +/* + * This routine should be called with the mq_lock held. + */ +static inline struct ipc_namespace *__get_ns_from_inode(struct inode *inode) +{ + return get_ipc_ns(inode->i_sb->s_fs_info); +} + +static struct ipc_namespace *get_ns_from_inode(struct inode *inode) +{ + struct ipc_namespace *ns; + + spin_lock(&mq_lock); + ns = __get_ns_from_inode(inode); + spin_unlock(&mq_lock); + return ns; +} + +/* Auxiliary functions to manipulate messages' list */ +static int msg_insert(struct msg_msg *msg, struct mqueue_inode_info *info) +{ + struct rb_node **p, *parent = NULL; + struct posix_msg_tree_node *leaf; + + p = &info->msg_tree.rb_node; + while (*p) { + parent = *p; + leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node); + + if (likely(leaf->priority == msg->m_type)) + goto insert_msg; + else if (msg->m_type < leaf->priority) + p = &(*p)->rb_left; + else + p = &(*p)->rb_right; + } + if (info->node_cache) { + leaf = info->node_cache; + info->node_cache = NULL; + } else { + leaf = kmalloc(sizeof(*leaf), GFP_ATOMIC); + if (!leaf) + return -ENOMEM; + INIT_LIST_HEAD(&leaf->msg_list); + info->qsize += sizeof(*leaf); + } + leaf->priority = msg->m_type; + rb_link_node(&leaf->rb_node, parent, p); + rb_insert_color(&leaf->rb_node, &info->msg_tree); +insert_msg: + info->attr.mq_curmsgs++; + info->qsize += msg->m_ts; + list_add_tail(&msg->m_list, &leaf->msg_list); + return 0; +} + +static inline struct msg_msg *msg_get(struct mqueue_inode_info *info) +{ + struct rb_node **p, *parent = NULL; + struct posix_msg_tree_node *leaf; + struct msg_msg *msg; + +try_again: + p = &info->msg_tree.rb_node; + while (*p) { + parent = *p; + /* + * During insert, low priorities go to the left and high to the + * right. On receive, we want the highest priorities first, so + * walk all the way to the right. + */ + p = &(*p)->rb_right; + } + if (!parent) { + if (info->attr.mq_curmsgs) { + pr_warn_once("Inconsistency in POSIX message queue, " + "no tree element, but supposedly messages " + "should exist!\n"); + info->attr.mq_curmsgs = 0; + } + return NULL; + } + leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node); + if (unlikely(list_empty(&leaf->msg_list))) { + pr_warn_once("Inconsistency in POSIX message queue, " + "empty leaf node but we haven't implemented " + "lazy leaf delete!\n"); + rb_erase(&leaf->rb_node, &info->msg_tree); + if (info->node_cache) { + info->qsize -= sizeof(*leaf); + kfree(leaf); + } else { + info->node_cache = leaf; + } + goto try_again; + } else { + msg = list_first_entry(&leaf->msg_list, + struct msg_msg, m_list); + list_del(&msg->m_list); + if (list_empty(&leaf->msg_list)) { + rb_erase(&leaf->rb_node, &info->msg_tree); + if (info->node_cache) { + info->qsize -= sizeof(*leaf); + kfree(leaf); + } else { + info->node_cache = leaf; + } + } + } + info->attr.mq_curmsgs--; + info->qsize -= msg->m_ts; + return msg; +} + +static struct inode *mqueue_get_inode(struct super_block *sb, + struct ipc_namespace *ipc_ns, umode_t mode, + struct mq_attr *attr) +{ + struct user_struct *u = current_user(); + struct inode *inode; + int ret = -ENOMEM; + + inode = new_inode(sb); + if (!inode) + goto err; + + inode->i_ino = get_next_ino(); + inode->i_mode = mode; + inode->i_uid = current_fsuid(); + inode->i_gid = current_fsgid(); + inode->i_mtime = inode->i_ctime = inode->i_atime = CURRENT_TIME; + + if (S_ISREG(mode)) { + struct mqueue_inode_info *info; + unsigned long mq_bytes, mq_treesize; + + inode->i_fop = &mqueue_file_operations; + inode->i_size = FILENT_SIZE; + /* mqueue specific info */ + info = MQUEUE_I(inode); + spin_lock_init(&info->lock); + init_waitqueue_head(&info->wait_q); + INIT_LIST_HEAD(&info->e_wait_q[0].list); + INIT_LIST_HEAD(&info->e_wait_q[1].list); + info->notify_owner = NULL; + info->notify_user_ns = NULL; + info->qsize = 0; + info->user = NULL; /* set when all is ok */ + info->msg_tree = RB_ROOT; + info->node_cache = NULL; + memset(&info->attr, 0, sizeof(info->attr)); + info->attr.mq_maxmsg = min(ipc_ns->mq_msg_max, + ipc_ns->mq_msg_default); + info->attr.mq_msgsize = min(ipc_ns->mq_msgsize_max, + ipc_ns->mq_msgsize_default); + if (attr) { + info->attr.mq_maxmsg = attr->mq_maxmsg; + info->attr.mq_msgsize = attr->mq_msgsize; + } + /* + * We used to allocate a static array of pointers and account + * the size of that array as well as one msg_msg struct per + * possible message into the queue size. That's no longer + * accurate as the queue is now an rbtree and will grow and + * shrink depending on usage patterns. We can, however, still + * account one msg_msg struct per message, but the nodes are + * allocated depending on priority usage, and most programs + * only use one, or a handful, of priorities. However, since + * this is pinned memory, we need to assume worst case, so + * that means the min(mq_maxmsg, max_priorities) * struct + * posix_msg_tree_node. + */ + mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) + + min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) * + sizeof(struct posix_msg_tree_node); + + mq_bytes = mq_treesize + (info->attr.mq_maxmsg * + info->attr.mq_msgsize); + + spin_lock(&mq_lock); + if (u->mq_bytes + mq_bytes < u->mq_bytes || + u->mq_bytes + mq_bytes > rlimit(RLIMIT_MSGQUEUE)) { + spin_unlock(&mq_lock); + /* mqueue_evict_inode() releases info->messages */ + ret = -EMFILE; + goto out_inode; + } + u->mq_bytes += mq_bytes; + spin_unlock(&mq_lock); + + /* all is ok */ + info->user = get_uid(u); + } else if (S_ISDIR(mode)) { + inc_nlink(inode); + /* Some things misbehave if size == 0 on a directory */ + inode->i_size = 2 * DIRENT_SIZE; + inode->i_op = &mqueue_dir_inode_operations; + inode->i_fop = &simple_dir_operations; + } + + return inode; +out_inode: + iput(inode); +err: + return ERR_PTR(ret); +} + +static int mqueue_fill_super(struct super_block *sb, void *data, int silent) +{ + struct inode *inode; + struct ipc_namespace *ns = data; + + sb->s_blocksize = PAGE_CACHE_SIZE; + sb->s_blocksize_bits = PAGE_CACHE_SHIFT; + sb->s_magic = MQUEUE_MAGIC; + sb->s_op = &mqueue_super_ops; + + inode = mqueue_get_inode(sb, ns, S_IFDIR | S_ISVTX | S_IRWXUGO, NULL); + if (IS_ERR(inode)) + return PTR_ERR(inode); + + sb->s_root = d_make_root(inode); + if (!sb->s_root) + return -ENOMEM; + return 0; +} + +static struct dentry *mqueue_mount(struct file_system_type *fs_type, + int flags, const char *dev_name, + void *data) +{ + if (!(flags & MS_KERNMOUNT)) { + struct ipc_namespace *ns = current->nsproxy->ipc_ns; + /* Don't allow mounting unless the caller has CAP_SYS_ADMIN + * over the ipc namespace. + */ + if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN)) + return ERR_PTR(-EPERM); + + data = ns; + } + return mount_ns(fs_type, flags, data, mqueue_fill_super); +} + +static void init_once(void *foo) +{ + struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo; + + inode_init_once(&p->vfs_inode); +} + +static struct inode *mqueue_alloc_inode(struct super_block *sb) +{ + struct mqueue_inode_info *ei; + + ei = kmem_cache_alloc(mqueue_inode_cachep, GFP_KERNEL); + if (!ei) + return NULL; + return &ei->vfs_inode; +} + +static void mqueue_i_callback(struct rcu_head *head) +{ + struct inode *inode = container_of(head, struct inode, i_rcu); + kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode)); +} + +static void mqueue_destroy_inode(struct inode *inode) +{ + call_rcu(&inode->i_rcu, mqueue_i_callback); +} + +static void mqueue_evict_inode(struct inode *inode) +{ + struct mqueue_inode_info *info; + struct user_struct *user; + unsigned long mq_bytes, mq_treesize; + struct ipc_namespace *ipc_ns; + struct msg_msg *msg; + + clear_inode(inode); + + if (S_ISDIR(inode->i_mode)) + return; + + ipc_ns = get_ns_from_inode(inode); + info = MQUEUE_I(inode); + spin_lock(&info->lock); + while ((msg = msg_get(info)) != NULL) + free_msg(msg); + kfree(info->node_cache); + spin_unlock(&info->lock); + + /* Total amount of bytes accounted for the mqueue */ + mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) + + min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) * + sizeof(struct posix_msg_tree_node); + + mq_bytes = mq_treesize + (info->attr.mq_maxmsg * + info->attr.mq_msgsize); + + user = info->user; + if (user) { + spin_lock(&mq_lock); + user->mq_bytes -= mq_bytes; + /* + * get_ns_from_inode() ensures that the + * (ipc_ns = sb->s_fs_info) is either a valid ipc_ns + * to which we now hold a reference, or it is NULL. + * We can't put it here under mq_lock, though. + */ + if (ipc_ns) + ipc_ns->mq_queues_count--; + spin_unlock(&mq_lock); + free_uid(user); + } + if (ipc_ns) + put_ipc_ns(ipc_ns); +} + +static int mqueue_create(struct inode *dir, struct dentry *dentry, + umode_t mode, bool excl) +{ + struct inode *inode; + struct mq_attr *attr = dentry->d_fsdata; + int error; + struct ipc_namespace *ipc_ns; + + spin_lock(&mq_lock); + ipc_ns = __get_ns_from_inode(dir); + if (!ipc_ns) { + error = -EACCES; + goto out_unlock; + } + + if (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max && + !capable(CAP_SYS_RESOURCE)) { + error = -ENOSPC; + goto out_unlock; + } + ipc_ns->mq_queues_count++; + spin_unlock(&mq_lock); + + inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr); + if (IS_ERR(inode)) { + error = PTR_ERR(inode); + spin_lock(&mq_lock); + ipc_ns->mq_queues_count--; + goto out_unlock; + } + + put_ipc_ns(ipc_ns); + dir->i_size += DIRENT_SIZE; + dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME; + + d_instantiate(dentry, inode); + dget(dentry); + return 0; +out_unlock: + spin_unlock(&mq_lock); + if (ipc_ns) + put_ipc_ns(ipc_ns); + return error; +} + +static int mqueue_unlink(struct inode *dir, struct dentry *dentry) +{ + struct inode *inode = d_inode(dentry); + + dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME; + dir->i_size -= DIRENT_SIZE; + drop_nlink(inode); + dput(dentry); + return 0; +} + +/* +* This is routine for system read from queue file. +* To avoid mess with doing here some sort of mq_receive we allow +* to read only queue size & notification info (the only values +* that are interesting from user point of view and aren't accessible +* through std routines) +*/ +static ssize_t mqueue_read_file(struct file *filp, char __user *u_data, + size_t count, loff_t *off) +{ + struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp)); + char buffer[FILENT_SIZE]; + ssize_t ret; + + spin_lock(&info->lock); + snprintf(buffer, sizeof(buffer), + "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n", + info->qsize, + info->notify_owner ? info->notify.sigev_notify : 0, + (info->notify_owner && + info->notify.sigev_notify == SIGEV_SIGNAL) ? + info->notify.sigev_signo : 0, + pid_vnr(info->notify_owner)); + spin_unlock(&info->lock); + buffer[sizeof(buffer)-1] = '\0'; + + ret = simple_read_from_buffer(u_data, count, off, buffer, + strlen(buffer)); + if (ret <= 0) + return ret; + + file_inode(filp)->i_atime = file_inode(filp)->i_ctime = CURRENT_TIME; + return ret; +} + +static int mqueue_flush_file(struct file *filp, fl_owner_t id) +{ + struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp)); + + spin_lock(&info->lock); + if (task_tgid(current) == info->notify_owner) + remove_notification(info); + + spin_unlock(&info->lock); + return 0; +} + +static unsigned int mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab) +{ + struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp)); + int retval = 0; + + poll_wait(filp, &info->wait_q, poll_tab); + + spin_lock(&info->lock); + if (info->attr.mq_curmsgs) + retval = POLLIN | POLLRDNORM; + + if (info->attr.mq_curmsgs < info->attr.mq_maxmsg) + retval |= POLLOUT | POLLWRNORM; + spin_unlock(&info->lock); + + return retval; +} + +/* Adds current to info->e_wait_q[sr] before element with smaller prio */ +static void wq_add(struct mqueue_inode_info *info, int sr, + struct ext_wait_queue *ewp) +{ + struct ext_wait_queue *walk; + + ewp->task = current; + + list_for_each_entry(walk, &info->e_wait_q[sr].list, list) { + if (walk->task->static_prio <= current->static_prio) { + list_add_tail(&ewp->list, &walk->list); + return; + } + } + list_add_tail(&ewp->list, &info->e_wait_q[sr].list); +} + +/* + * Puts current task to sleep. Caller must hold queue lock. After return + * lock isn't held. + * sr: SEND or RECV + */ +static int wq_sleep(struct mqueue_inode_info *info, int sr, + ktime_t *timeout, struct ext_wait_queue *ewp) +{ + int retval; + signed long time; + + wq_add(info, sr, ewp); + + for (;;) { + __set_current_state(TASK_INTERRUPTIBLE); + + spin_unlock(&info->lock); + time = schedule_hrtimeout_range_clock(timeout, 0, + HRTIMER_MODE_ABS, CLOCK_REALTIME); + + if (ewp->state == STATE_READY) { + retval = 0; + goto out; + } + spin_lock(&info->lock); + if (ewp->state == STATE_READY) { + retval = 0; + goto out_unlock; + } + if (signal_pending(current)) { + retval = -ERESTARTSYS; + break; + } + if (time == 0) { + retval = -ETIMEDOUT; + break; + } + } + list_del(&ewp->list); +out_unlock: + spin_unlock(&info->lock); +out: + return retval; +} + +/* + * Returns waiting task that should be serviced first or NULL if none exists + */ +static struct ext_wait_queue *wq_get_first_waiter( + struct mqueue_inode_info *info, int sr) +{ + struct list_head *ptr; + + ptr = info->e_wait_q[sr].list.prev; + if (ptr == &info->e_wait_q[sr].list) + return NULL; + return list_entry(ptr, struct ext_wait_queue, list); +} + + +static inline void set_cookie(struct sk_buff *skb, char code) +{ + ((char *)skb->data)[NOTIFY_COOKIE_LEN-1] = code; +} + +/* + * The next function is only to split too long sys_mq_timedsend + */ +static void __do_notify(struct mqueue_inode_info *info) +{ + /* notification + * invoked when there is registered process and there isn't process + * waiting synchronously for message AND state of queue changed from + * empty to not empty. Here we are sure that no one is waiting + * synchronously. */ + if (info->notify_owner && + info->attr.mq_curmsgs == 1) { + struct siginfo sig_i; + switch (info->notify.sigev_notify) { + case SIGEV_NONE: + break; + case SIGEV_SIGNAL: + /* sends signal */ + + sig_i.si_signo = info->notify.sigev_signo; + sig_i.si_errno = 0; + sig_i.si_code = SI_MESGQ; + sig_i.si_value = info->notify.sigev_value; + /* map current pid/uid into info->owner's namespaces */ + rcu_read_lock(); + sig_i.si_pid = task_tgid_nr_ns(current, + ns_of_pid(info->notify_owner)); + sig_i.si_uid = from_kuid_munged(info->notify_user_ns, current_uid()); + rcu_read_unlock(); + + kill_pid_info(info->notify.sigev_signo, + &sig_i, info->notify_owner); + break; + case SIGEV_THREAD: + set_cookie(info->notify_cookie, NOTIFY_WOKENUP); + netlink_sendskb(info->notify_sock, info->notify_cookie); + break; + } + /* after notification unregisters process */ + put_pid(info->notify_owner); + put_user_ns(info->notify_user_ns); + info->notify_owner = NULL; + info->notify_user_ns = NULL; + } + wake_up(&info->wait_q); +} + +static int prepare_timeout(const struct timespec __user *u_abs_timeout, + ktime_t *expires, struct timespec *ts) +{ + if (copy_from_user(ts, u_abs_timeout, sizeof(struct timespec))) + return -EFAULT; + if (!timespec_valid(ts)) + return -EINVAL; + + *expires = timespec_to_ktime(*ts); + return 0; +} + +static void remove_notification(struct mqueue_inode_info *info) +{ + if (info->notify_owner != NULL && + info->notify.sigev_notify == SIGEV_THREAD) { + set_cookie(info->notify_cookie, NOTIFY_REMOVED); + netlink_sendskb(info->notify_sock, info->notify_cookie); + } + put_pid(info->notify_owner); + put_user_ns(info->notify_user_ns); + info->notify_owner = NULL; + info->notify_user_ns = NULL; +} + +static int mq_attr_ok(struct ipc_namespace *ipc_ns, struct mq_attr *attr) +{ + int mq_treesize; + unsigned long total_size; + + if (attr->mq_maxmsg <= 0 || attr->mq_msgsize <= 0) + return -EINVAL; + if (capable(CAP_SYS_RESOURCE)) { + if (attr->mq_maxmsg > HARD_MSGMAX || + attr->mq_msgsize > HARD_MSGSIZEMAX) + return -EINVAL; + } else { + if (attr->mq_maxmsg > ipc_ns->mq_msg_max || + attr->mq_msgsize > ipc_ns->mq_msgsize_max) + return -EINVAL; + } + /* check for overflow */ + if (attr->mq_msgsize > ULONG_MAX/attr->mq_maxmsg) + return -EOVERFLOW; + mq_treesize = attr->mq_maxmsg * sizeof(struct msg_msg) + + min_t(unsigned int, attr->mq_maxmsg, MQ_PRIO_MAX) * + sizeof(struct posix_msg_tree_node); + total_size = attr->mq_maxmsg * attr->mq_msgsize; + if (total_size + mq_treesize < total_size) + return -EOVERFLOW; + return 0; +} + +/* + * Invoked when creating a new queue via sys_mq_open + */ +static struct file *do_create(struct ipc_namespace *ipc_ns, struct inode *dir, + struct path *path, int oflag, umode_t mode, + struct mq_attr *attr) +{ + const struct cred *cred = current_cred(); + int ret; + + if (attr) { + ret = mq_attr_ok(ipc_ns, attr); + if (ret) + return ERR_PTR(ret); + /* store for use during create */ + path->dentry->d_fsdata = attr; + } else { + struct mq_attr def_attr; + + def_attr.mq_maxmsg = min(ipc_ns->mq_msg_max, + ipc_ns->mq_msg_default); + def_attr.mq_msgsize = min(ipc_ns->mq_msgsize_max, + ipc_ns->mq_msgsize_default); + ret = mq_attr_ok(ipc_ns, &def_attr); + if (ret) + return ERR_PTR(ret); + } + + mode &= ~current_umask(); + ret = vfs_create(dir, path->dentry, mode, true); + path->dentry->d_fsdata = NULL; + if (ret) + return ERR_PTR(ret); + return dentry_open(path, oflag, cred); +} + +/* Opens existing queue */ +static struct file *do_open(struct path *path, int oflag) +{ + static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE, + MAY_READ | MAY_WRITE }; + int acc; + if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY)) + return ERR_PTR(-EINVAL); + acc = oflag2acc[oflag & O_ACCMODE]; + if (inode_permission(d_inode(path->dentry), acc)) + return ERR_PTR(-EACCES); + return dentry_open(path, oflag, current_cred()); +} + +SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, umode_t, mode, + struct mq_attr __user *, u_attr) +{ + struct path path; + struct file *filp; + struct filename *name; + struct mq_attr attr; + int fd, error; + struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns; + struct vfsmount *mnt = ipc_ns->mq_mnt; + struct dentry *root = mnt->mnt_root; + int ro; + + if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr))) + return -EFAULT; + + audit_mq_open(oflag, mode, u_attr ? &attr : NULL); + + if (IS_ERR(name = getname(u_name))) + return PTR_ERR(name); + + fd = get_unused_fd_flags(O_CLOEXEC); + if (fd < 0) + goto out_putname; + + ro = mnt_want_write(mnt); /* we'll drop it in any case */ + error = 0; + mutex_lock(&d_inode(root)->i_mutex); + path.dentry = lookup_one_len(name->name, root, strlen(name->name)); + if (IS_ERR(path.dentry)) { + error = PTR_ERR(path.dentry); + goto out_putfd; + } + path.mnt = mntget(mnt); + + if (oflag & O_CREAT) { + if (d_really_is_positive(path.dentry)) { /* entry already exists */ + audit_inode(name, path.dentry, 0); + if (oflag & O_EXCL) { + error = -EEXIST; + goto out; + } + filp = do_open(&path, oflag); + } else { + if (ro) { + error = ro; + goto out; + } + audit_inode_parent_hidden(name, root); + filp = do_create(ipc_ns, d_inode(root), + &path, oflag, mode, + u_attr ? &attr : NULL); + } + } else { + if (d_really_is_negative(path.dentry)) { + error = -ENOENT; + goto out; + } + audit_inode(name, path.dentry, 0); + filp = do_open(&path, oflag); + } + + if (!IS_ERR(filp)) + fd_install(fd, filp); + else + error = PTR_ERR(filp); +out: + path_put(&path); +out_putfd: + if (error) { + put_unused_fd(fd); + fd = error; + } + mutex_unlock(&d_inode(root)->i_mutex); + if (!ro) + mnt_drop_write(mnt); +out_putname: + putname(name); + return fd; +} + +SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name) +{ + int err; + struct filename *name; + struct dentry *dentry; + struct inode *inode = NULL; + struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns; + struct vfsmount *mnt = ipc_ns->mq_mnt; + + name = getname(u_name); + if (IS_ERR(name)) + return PTR_ERR(name); + + audit_inode_parent_hidden(name, mnt->mnt_root); + err = mnt_want_write(mnt); + if (err) + goto out_name; + mutex_lock_nested(&d_inode(mnt->mnt_root)->i_mutex, I_MUTEX_PARENT); + dentry = lookup_one_len(name->name, mnt->mnt_root, + strlen(name->name)); + if (IS_ERR(dentry)) { + err = PTR_ERR(dentry); + goto out_unlock; + } + + inode = d_inode(dentry); + if (!inode) { + err = -ENOENT; + } else { + ihold(inode); + err = vfs_unlink(d_inode(dentry->d_parent), dentry, NULL); + } + dput(dentry); + +out_unlock: + mutex_unlock(&d_inode(mnt->mnt_root)->i_mutex); + if (inode) + iput(inode); + mnt_drop_write(mnt); +out_name: + putname(name); + + return err; +} + +/* Pipelined send and receive functions. + * + * If a receiver finds no waiting message, then it registers itself in the + * list of waiting receivers. A sender checks that list before adding the new + * message into the message array. If there is a waiting receiver, then it + * bypasses the message array and directly hands the message over to the + * receiver. The receiver accepts the message and returns without grabbing the + * queue spinlock: + * + * - Set pointer to message. + * - Queue the receiver task for later wakeup (without the info->lock). + * - Update its state to STATE_READY. Now the receiver can continue. + * - Wake up the process after the lock is dropped. Should the process wake up + * before this wakeup (due to a timeout or a signal) it will either see + * STATE_READY and continue or acquire the lock to check the state again. + * + * The same algorithm is used for senders. + */ + +/* pipelined_send() - send a message directly to the task waiting in + * sys_mq_timedreceive() (without inserting message into a queue). + */ +static inline void pipelined_send(struct wake_q_head *wake_q, + struct mqueue_inode_info *info, + struct msg_msg *message, + struct ext_wait_queue *receiver) +{ + receiver->msg = message; + list_del(&receiver->list); + wake_q_add(wake_q, receiver->task); + /* + * Rely on the implicit cmpxchg barrier from wake_q_add such + * that we can ensure that updating receiver->state is the last + * write operation: As once set, the receiver can continue, + * and if we don't have the reference count from the wake_q, + * yet, at that point we can later have a use-after-free + * condition and bogus wakeup. + */ + receiver->state = STATE_READY; +} + +/* pipelined_receive() - if there is task waiting in sys_mq_timedsend() + * gets its message and put to the queue (we have one free place for sure). */ +static inline void pipelined_receive(struct wake_q_head *wake_q, + struct mqueue_inode_info *info) +{ + struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND); + + if (!sender) { + /* for poll */ + wake_up_interruptible(&info->wait_q); + return; + } + if (msg_insert(sender->msg, info)) + return; + + list_del(&sender->list); + wake_q_add(wake_q, sender->task); + sender->state = STATE_READY; +} + +SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr, + size_t, msg_len, unsigned int, msg_prio, + const struct timespec __user *, u_abs_timeout) +{ + struct fd f; + struct inode *inode; + struct ext_wait_queue wait; + struct ext_wait_queue *receiver; + struct msg_msg *msg_ptr; + struct mqueue_inode_info *info; + ktime_t expires, *timeout = NULL; + struct timespec ts; + struct posix_msg_tree_node *new_leaf = NULL; + int ret = 0; + WAKE_Q(wake_q); + + if (u_abs_timeout) { + int res = prepare_timeout(u_abs_timeout, &expires, &ts); + if (res) + return res; + timeout = &expires; + } + + if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX)) + return -EINVAL; + + audit_mq_sendrecv(mqdes, msg_len, msg_prio, timeout ? &ts : NULL); + + f = fdget(mqdes); + if (unlikely(!f.file)) { + ret = -EBADF; + goto out; + } + + inode = file_inode(f.file); + if (unlikely(f.file->f_op != &mqueue_file_operations)) { + ret = -EBADF; + goto out_fput; + } + info = MQUEUE_I(inode); + audit_file(f.file); + + if (unlikely(!(f.file->f_mode & FMODE_WRITE))) { + ret = -EBADF; + goto out_fput; + } + + if (unlikely(msg_len > info->attr.mq_msgsize)) { + ret = -EMSGSIZE; + goto out_fput; + } + + /* First try to allocate memory, before doing anything with + * existing queues. */ + msg_ptr = load_msg(u_msg_ptr, msg_len); + if (IS_ERR(msg_ptr)) { + ret = PTR_ERR(msg_ptr); + goto out_fput; + } + msg_ptr->m_ts = msg_len; + msg_ptr->m_type = msg_prio; + + /* + * msg_insert really wants us to have a valid, spare node struct so + * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will + * fall back to that if necessary. + */ + if (!info->node_cache) + new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL); + + spin_lock(&info->lock); + + if (!info->node_cache && new_leaf) { + /* Save our speculative allocation into the cache */ + INIT_LIST_HEAD(&new_leaf->msg_list); + info->node_cache = new_leaf; + info->qsize += sizeof(*new_leaf); + new_leaf = NULL; + } else { + kfree(new_leaf); + } + + if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) { + if (f.file->f_flags & O_NONBLOCK) { + ret = -EAGAIN; + } else { + wait.task = current; + wait.msg = (void *) msg_ptr; + wait.state = STATE_NONE; + ret = wq_sleep(info, SEND, timeout, &wait); + /* + * wq_sleep must be called with info->lock held, and + * returns with the lock released + */ + goto out_free; + } + } else { + receiver = wq_get_first_waiter(info, RECV); + if (receiver) { + pipelined_send(&wake_q, info, msg_ptr, receiver); + } else { + /* adds message to the queue */ + ret = msg_insert(msg_ptr, info); + if (ret) + goto out_unlock; + __do_notify(info); + } + inode->i_atime = inode->i_mtime = inode->i_ctime = + CURRENT_TIME; + } +out_unlock: + spin_unlock(&info->lock); + wake_up_q(&wake_q); +out_free: + if (ret) + free_msg(msg_ptr); +out_fput: + fdput(f); +out: + return ret; +} + +SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr, + size_t, msg_len, unsigned int __user *, u_msg_prio, + const struct timespec __user *, u_abs_timeout) +{ + ssize_t ret; + struct msg_msg *msg_ptr; + struct fd f; + struct inode *inode; + struct mqueue_inode_info *info; + struct ext_wait_queue wait; + ktime_t expires, *timeout = NULL; + struct timespec ts; + struct posix_msg_tree_node *new_leaf = NULL; + + if (u_abs_timeout) { + int res = prepare_timeout(u_abs_timeout, &expires, &ts); + if (res) + return res; + timeout = &expires; + } + + audit_mq_sendrecv(mqdes, msg_len, 0, timeout ? &ts : NULL); + + f = fdget(mqdes); + if (unlikely(!f.file)) { + ret = -EBADF; + goto out; + } + + inode = file_inode(f.file); + if (unlikely(f.file->f_op != &mqueue_file_operations)) { + ret = -EBADF; + goto out_fput; + } + info = MQUEUE_I(inode); + audit_file(f.file); + + if (unlikely(!(f.file->f_mode & FMODE_READ))) { + ret = -EBADF; + goto out_fput; + } + + /* checks if buffer is big enough */ + if (unlikely(msg_len < info->attr.mq_msgsize)) { + ret = -EMSGSIZE; + goto out_fput; + } + + /* + * msg_insert really wants us to have a valid, spare node struct so + * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will + * fall back to that if necessary. + */ + if (!info->node_cache) + new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL); + + spin_lock(&info->lock); + + if (!info->node_cache && new_leaf) { + /* Save our speculative allocation into the cache */ + INIT_LIST_HEAD(&new_leaf->msg_list); + info->node_cache = new_leaf; + info->qsize += sizeof(*new_leaf); + } else { + kfree(new_leaf); + } + + if (info->attr.mq_curmsgs == 0) { + if (f.file->f_flags & O_NONBLOCK) { + spin_unlock(&info->lock); + ret = -EAGAIN; + } else { + wait.task = current; + wait.state = STATE_NONE; + ret = wq_sleep(info, RECV, timeout, &wait); + msg_ptr = wait.msg; + } + } else { + WAKE_Q(wake_q); + + msg_ptr = msg_get(info); + + inode->i_atime = inode->i_mtime = inode->i_ctime = + CURRENT_TIME; + + /* There is now free space in queue. */ + pipelined_receive(&wake_q, info); + spin_unlock(&info->lock); + wake_up_q(&wake_q); + ret = 0; + } + if (ret == 0) { + ret = msg_ptr->m_ts; + + if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) || + store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) { + ret = -EFAULT; + } + free_msg(msg_ptr); + } +out_fput: + fdput(f); +out: + return ret; +} + +/* + * Notes: the case when user wants us to deregister (with NULL as pointer) + * and he isn't currently owner of notification, will be silently discarded. + * It isn't explicitly defined in the POSIX. + */ +SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes, + const struct sigevent __user *, u_notification) +{ + int ret; + struct fd f; + struct sock *sock; + struct inode *inode; + struct sigevent notification; + struct mqueue_inode_info *info; + struct sk_buff *nc; + + if (u_notification) { + if (copy_from_user(¬ification, u_notification, + sizeof(struct sigevent))) + return -EFAULT; + } + + audit_mq_notify(mqdes, u_notification ? ¬ification : NULL); + + nc = NULL; + sock = NULL; + if (u_notification != NULL) { + if (unlikely(notification.sigev_notify != SIGEV_NONE && + notification.sigev_notify != SIGEV_SIGNAL && + notification.sigev_notify != SIGEV_THREAD)) + return -EINVAL; + if (notification.sigev_notify == SIGEV_SIGNAL && + !valid_signal(notification.sigev_signo)) { + return -EINVAL; + } + if (notification.sigev_notify == SIGEV_THREAD) { + long timeo; + + /* create the notify skb */ + nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL); + if (!nc) { + ret = -ENOMEM; + goto out; + } + if (copy_from_user(nc->data, + notification.sigev_value.sival_ptr, + NOTIFY_COOKIE_LEN)) { + ret = -EFAULT; + goto out; + } + + /* TODO: add a header? */ + skb_put(nc, NOTIFY_COOKIE_LEN); + /* and attach it to the socket */ +retry: + f = fdget(notification.sigev_signo); + if (!f.file) { + ret = -EBADF; + goto out; + } + sock = netlink_getsockbyfilp(f.file); + fdput(f); + if (IS_ERR(sock)) { + ret = PTR_ERR(sock); + sock = NULL; + goto out; + } + + timeo = MAX_SCHEDULE_TIMEOUT; + ret = netlink_attachskb(sock, nc, &timeo, NULL); + if (ret == 1) + goto retry; + if (ret) { + sock = NULL; + nc = NULL; + goto out; + } + } + } + + f = fdget(mqdes); + if (!f.file) { + ret = -EBADF; + goto out; + } + + inode = file_inode(f.file); + if (unlikely(f.file->f_op != &mqueue_file_operations)) { + ret = -EBADF; + goto out_fput; + } + info = MQUEUE_I(inode); + + ret = 0; + spin_lock(&info->lock); + if (u_notification == NULL) { + if (info->notify_owner == task_tgid(current)) { + remove_notification(info); + inode->i_atime = inode->i_ctime = CURRENT_TIME; + } + } else if (info->notify_owner != NULL) { + ret = -EBUSY; + } else { + switch (notification.sigev_notify) { + case SIGEV_NONE: + info->notify.sigev_notify = SIGEV_NONE; + break; + case SIGEV_THREAD: + info->notify_sock = sock; + info->notify_cookie = nc; + sock = NULL; + nc = NULL; + info->notify.sigev_notify = SIGEV_THREAD; + break; + case SIGEV_SIGNAL: + info->notify.sigev_signo = notification.sigev_signo; + info->notify.sigev_value = notification.sigev_value; + info->notify.sigev_notify = SIGEV_SIGNAL; + break; + } + + info->notify_owner = get_pid(task_tgid(current)); + info->notify_user_ns = get_user_ns(current_user_ns()); + inode->i_atime = inode->i_ctime = CURRENT_TIME; + } + spin_unlock(&info->lock); +out_fput: + fdput(f); +out: + if (sock) + netlink_detachskb(sock, nc); + else if (nc) + dev_kfree_skb(nc); + + return ret; +} + +SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes, + const struct mq_attr __user *, u_mqstat, + struct mq_attr __user *, u_omqstat) +{ + int ret; + struct mq_attr mqstat, omqstat; + struct fd f; + struct inode *inode; + struct mqueue_inode_info *info; + + if (u_mqstat != NULL) { + if (copy_from_user(&mqstat, u_mqstat, sizeof(struct mq_attr))) + return -EFAULT; + if (mqstat.mq_flags & (~O_NONBLOCK)) + return -EINVAL; + } + + f = fdget(mqdes); + if (!f.file) { + ret = -EBADF; + goto out; + } + + inode = file_inode(f.file); + if (unlikely(f.file->f_op != &mqueue_file_operations)) { + ret = -EBADF; + goto out_fput; + } + info = MQUEUE_I(inode); + + spin_lock(&info->lock); + + omqstat = info->attr; + omqstat.mq_flags = f.file->f_flags & O_NONBLOCK; + if (u_mqstat) { + audit_mq_getsetattr(mqdes, &mqstat); + spin_lock(&f.file->f_lock); + if (mqstat.mq_flags & O_NONBLOCK) + f.file->f_flags |= O_NONBLOCK; + else + f.file->f_flags &= ~O_NONBLOCK; + spin_unlock(&f.file->f_lock); + + inode->i_atime = inode->i_ctime = CURRENT_TIME; + } + + spin_unlock(&info->lock); + + ret = 0; + if (u_omqstat != NULL && copy_to_user(u_omqstat, &omqstat, + sizeof(struct mq_attr))) + ret = -EFAULT; + +out_fput: + fdput(f); +out: + return ret; +} + +static const struct inode_operations mqueue_dir_inode_operations = { + .lookup = simple_lookup, + .create = mqueue_create, + .unlink = mqueue_unlink, +}; + +static const struct file_operations mqueue_file_operations = { + .flush = mqueue_flush_file, + .poll = mqueue_poll_file, + .read = mqueue_read_file, + .llseek = default_llseek, +}; + +static const struct super_operations mqueue_super_ops = { + .alloc_inode = mqueue_alloc_inode, + .destroy_inode = mqueue_destroy_inode, + .evict_inode = mqueue_evict_inode, + .statfs = simple_statfs, +}; + +static struct file_system_type mqueue_fs_type = { + .name = "mqueue", + .mount = mqueue_mount, + .kill_sb = kill_litter_super, + .fs_flags = FS_USERNS_MOUNT, +}; + +int mq_init_ns(struct ipc_namespace *ns) +{ + ns->mq_queues_count = 0; + ns->mq_queues_max = DFLT_QUEUESMAX; + ns->mq_msg_max = DFLT_MSGMAX; + ns->mq_msgsize_max = DFLT_MSGSIZEMAX; + ns->mq_msg_default = DFLT_MSG; + ns->mq_msgsize_default = DFLT_MSGSIZE; + + ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns); + if (IS_ERR(ns->mq_mnt)) { + int err = PTR_ERR(ns->mq_mnt); + ns->mq_mnt = NULL; + return err; + } + return 0; +} + +void mq_clear_sbinfo(struct ipc_namespace *ns) +{ + ns->mq_mnt->mnt_sb->s_fs_info = NULL; +} + +void mq_put_mnt(struct ipc_namespace *ns) +{ + kern_unmount(ns->mq_mnt); +} + +static int __init init_mqueue_fs(void) +{ + int error; + + mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache", + sizeof(struct mqueue_inode_info), 0, + SLAB_HWCACHE_ALIGN, init_once); + if (mqueue_inode_cachep == NULL) + return -ENOMEM; + + /* ignore failures - they are not fatal */ + mq_sysctl_table = mq_register_sysctl_table(); + + error = register_filesystem(&mqueue_fs_type); + if (error) + goto out_sysctl; + + spin_lock_init(&mq_lock); + + error = mq_init_ns(&init_ipc_ns); + if (error) + goto out_filesystem; + + return 0; + +out_filesystem: + unregister_filesystem(&mqueue_fs_type); +out_sysctl: + if (mq_sysctl_table) + unregister_sysctl_table(mq_sysctl_table); + kmem_cache_destroy(mqueue_inode_cachep); + return error; +} + +device_initcall(init_mqueue_fs); diff --git a/kernel/ipc/msg.c b/kernel/ipc/msg.c new file mode 100644 index 000000000..cedbf5f50 --- /dev/null +++ b/kernel/ipc/msg.c @@ -0,0 +1,1060 @@ +/* + * linux/ipc/msg.c + * Copyright (C) 1992 Krishna Balasubramanian + * + * Removed all the remaining kerneld mess + * Catch the -EFAULT stuff properly + * Use GFP_KERNEL for messages as in 1.2 + * Fixed up the unchecked user space derefs + * Copyright (C) 1998 Alan Cox & Andi Kleen + * + * /proc/sysvipc/msg support (c) 1999 Dragos Acostachioaie + * + * mostly rewritten, threaded and wake-one semantics added + * MSGMAX limit removed, sysctl's added + * (c) 1999 Manfred Spraul + * + * support for audit of ipc object properties and permission changes + * Dustin Kirkland + * + * namespaces support + * OpenVZ, SWsoft Inc. + * Pavel Emelianov + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include "util.h" + +/* one msg_receiver structure for each sleeping receiver */ +struct msg_receiver { + struct list_head r_list; + struct task_struct *r_tsk; + + int r_mode; + long r_msgtype; + long r_maxsize; + + /* + * Mark r_msg volatile so that the compiler + * does not try to get smart and optimize + * it. We rely on this for the lockless + * receive algorithm. + */ + struct msg_msg *volatile r_msg; +}; + +/* one msg_sender for each sleeping sender */ +struct msg_sender { + struct list_head list; + struct task_struct *tsk; +}; + +#define SEARCH_ANY 1 +#define SEARCH_EQUAL 2 +#define SEARCH_NOTEQUAL 3 +#define SEARCH_LESSEQUAL 4 +#define SEARCH_NUMBER 5 + +#define msg_ids(ns) ((ns)->ids[IPC_MSG_IDS]) + +static inline struct msg_queue *msq_obtain_object(struct ipc_namespace *ns, int id) +{ + struct kern_ipc_perm *ipcp = ipc_obtain_object(&msg_ids(ns), id); + + if (IS_ERR(ipcp)) + return ERR_CAST(ipcp); + + return container_of(ipcp, struct msg_queue, q_perm); +} + +static inline struct msg_queue *msq_obtain_object_check(struct ipc_namespace *ns, + int id) +{ + struct kern_ipc_perm *ipcp = ipc_obtain_object_check(&msg_ids(ns), id); + + if (IS_ERR(ipcp)) + return ERR_CAST(ipcp); + + return container_of(ipcp, struct msg_queue, q_perm); +} + +static inline void msg_rmid(struct ipc_namespace *ns, struct msg_queue *s) +{ + ipc_rmid(&msg_ids(ns), &s->q_perm); +} + +static void msg_rcu_free(struct rcu_head *head) +{ + struct ipc_rcu *p = container_of(head, struct ipc_rcu, rcu); + struct msg_queue *msq = ipc_rcu_to_struct(p); + + security_msg_queue_free(msq); + ipc_rcu_free(head); +} + +/** + * newque - Create a new msg queue + * @ns: namespace + * @params: ptr to the structure that contains the key and msgflg + * + * Called with msg_ids.rwsem held (writer) + */ +static int newque(struct ipc_namespace *ns, struct ipc_params *params) +{ + struct msg_queue *msq; + int id, retval; + key_t key = params->key; + int msgflg = params->flg; + + msq = ipc_rcu_alloc(sizeof(*msq)); + if (!msq) + return -ENOMEM; + + msq->q_perm.mode = msgflg & S_IRWXUGO; + msq->q_perm.key = key; + + msq->q_perm.security = NULL; + retval = security_msg_queue_alloc(msq); + if (retval) { + ipc_rcu_putref(msq, ipc_rcu_free); + return retval; + } + + /* ipc_addid() locks msq upon success. */ + id = ipc_addid(&msg_ids(ns), &msq->q_perm, ns->msg_ctlmni); + if (id < 0) { + ipc_rcu_putref(msq, msg_rcu_free); + return id; + } + + msq->q_stime = msq->q_rtime = 0; + msq->q_ctime = get_seconds(); + msq->q_cbytes = msq->q_qnum = 0; + msq->q_qbytes = ns->msg_ctlmnb; + msq->q_lspid = msq->q_lrpid = 0; + INIT_LIST_HEAD(&msq->q_messages); + INIT_LIST_HEAD(&msq->q_receivers); + INIT_LIST_HEAD(&msq->q_senders); + + ipc_unlock_object(&msq->q_perm); + rcu_read_unlock(); + + return msq->q_perm.id; +} + +static inline void ss_add(struct msg_queue *msq, struct msg_sender *mss) +{ + mss->tsk = current; + __set_current_state(TASK_INTERRUPTIBLE); + list_add_tail(&mss->list, &msq->q_senders); +} + +static inline void ss_del(struct msg_sender *mss) +{ + if (mss->list.next != NULL) + list_del(&mss->list); +} + +static void ss_wakeup(struct list_head *h, int kill) +{ + struct msg_sender *mss, *t; + + list_for_each_entry_safe(mss, t, h, list) { + if (kill) + mss->list.next = NULL; + wake_up_process(mss->tsk); + } +} + +static void expunge_all(struct msg_queue *msq, int res) +{ + struct msg_receiver *msr, *t; + + list_for_each_entry_safe(msr, t, &msq->q_receivers, r_list) { + /* + * Make sure that the wakeup doesnt preempt + * this CPU prematurely. (on PREEMPT_RT) + */ + preempt_disable_rt(); + + msr->r_msg = NULL; /* initialize expunge ordering */ + wake_up_process(msr->r_tsk); + /* + * Ensure that the wakeup is visible before setting r_msg as + * the receiving end depends on it: either spinning on a nil, + * or dealing with -EAGAIN cases. See lockless receive part 1 + * and 2 in do_msgrcv(). + */ + smp_mb(); + msr->r_msg = ERR_PTR(res); + + preempt_enable_rt(); + } +} + +/* + * freeque() wakes up waiters on the sender and receiver waiting queue, + * removes the message queue from message queue ID IDR, and cleans up all the + * messages associated with this queue. + * + * msg_ids.rwsem (writer) and the spinlock for this message queue are held + * before freeque() is called. msg_ids.rwsem remains locked on exit. + */ +static void freeque(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp) +{ + struct msg_msg *msg, *t; + struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm); + + expunge_all(msq, -EIDRM); + ss_wakeup(&msq->q_senders, 1); + msg_rmid(ns, msq); + ipc_unlock_object(&msq->q_perm); + rcu_read_unlock(); + + list_for_each_entry_safe(msg, t, &msq->q_messages, m_list) { + atomic_dec(&ns->msg_hdrs); + free_msg(msg); + } + atomic_sub(msq->q_cbytes, &ns->msg_bytes); + ipc_rcu_putref(msq, msg_rcu_free); +} + +/* + * Called with msg_ids.rwsem and ipcp locked. + */ +static inline int msg_security(struct kern_ipc_perm *ipcp, int msgflg) +{ + struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm); + + return security_msg_queue_associate(msq, msgflg); +} + +SYSCALL_DEFINE2(msgget, key_t, key, int, msgflg) +{ + struct ipc_namespace *ns; + static const struct ipc_ops msg_ops = { + .getnew = newque, + .associate = msg_security, + }; + struct ipc_params msg_params; + + ns = current->nsproxy->ipc_ns; + + msg_params.key = key; + msg_params.flg = msgflg; + + return ipcget(ns, &msg_ids(ns), &msg_ops, &msg_params); +} + +static inline unsigned long +copy_msqid_to_user(void __user *buf, struct msqid64_ds *in, int version) +{ + switch (version) { + case IPC_64: + return copy_to_user(buf, in, sizeof(*in)); + case IPC_OLD: + { + struct msqid_ds out; + + memset(&out, 0, sizeof(out)); + + ipc64_perm_to_ipc_perm(&in->msg_perm, &out.msg_perm); + + out.msg_stime = in->msg_stime; + out.msg_rtime = in->msg_rtime; + out.msg_ctime = in->msg_ctime; + + if (in->msg_cbytes > USHRT_MAX) + out.msg_cbytes = USHRT_MAX; + else + out.msg_cbytes = in->msg_cbytes; + out.msg_lcbytes = in->msg_cbytes; + + if (in->msg_qnum > USHRT_MAX) + out.msg_qnum = USHRT_MAX; + else + out.msg_qnum = in->msg_qnum; + + if (in->msg_qbytes > USHRT_MAX) + out.msg_qbytes = USHRT_MAX; + else + out.msg_qbytes = in->msg_qbytes; + out.msg_lqbytes = in->msg_qbytes; + + out.msg_lspid = in->msg_lspid; + out.msg_lrpid = in->msg_lrpid; + + return copy_to_user(buf, &out, sizeof(out)); + } + default: + return -EINVAL; + } +} + +static inline unsigned long +copy_msqid_from_user(struct msqid64_ds *out, void __user *buf, int version) +{ + switch (version) { + case IPC_64: + if (copy_from_user(out, buf, sizeof(*out))) + return -EFAULT; + return 0; + case IPC_OLD: + { + struct msqid_ds tbuf_old; + + if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old))) + return -EFAULT; + + out->msg_perm.uid = tbuf_old.msg_perm.uid; + out->msg_perm.gid = tbuf_old.msg_perm.gid; + out->msg_perm.mode = tbuf_old.msg_perm.mode; + + if (tbuf_old.msg_qbytes == 0) + out->msg_qbytes = tbuf_old.msg_lqbytes; + else + out->msg_qbytes = tbuf_old.msg_qbytes; + + return 0; + } + default: + return -EINVAL; + } +} + +/* + * This function handles some msgctl commands which require the rwsem + * to be held in write mode. + * NOTE: no locks must be held, the rwsem is taken inside this function. + */ +static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd, + struct msqid_ds __user *buf, int version) +{ + struct kern_ipc_perm *ipcp; + struct msqid64_ds uninitialized_var(msqid64); + struct msg_queue *msq; + int err; + + if (cmd == IPC_SET) { + if (copy_msqid_from_user(&msqid64, buf, version)) + return -EFAULT; + } + + down_write(&msg_ids(ns).rwsem); + rcu_read_lock(); + + ipcp = ipcctl_pre_down_nolock(ns, &msg_ids(ns), msqid, cmd, + &msqid64.msg_perm, msqid64.msg_qbytes); + if (IS_ERR(ipcp)) { + err = PTR_ERR(ipcp); + goto out_unlock1; + } + + msq = container_of(ipcp, struct msg_queue, q_perm); + + err = security_msg_queue_msgctl(msq, cmd); + if (err) + goto out_unlock1; + + switch (cmd) { + case IPC_RMID: + ipc_lock_object(&msq->q_perm); + /* freeque unlocks the ipc object and rcu */ + freeque(ns, ipcp); + goto out_up; + case IPC_SET: + if (msqid64.msg_qbytes > ns->msg_ctlmnb && + !capable(CAP_SYS_RESOURCE)) { + err = -EPERM; + goto out_unlock1; + } + + ipc_lock_object(&msq->q_perm); + err = ipc_update_perm(&msqid64.msg_perm, ipcp); + if (err) + goto out_unlock0; + + msq->q_qbytes = msqid64.msg_qbytes; + + msq->q_ctime = get_seconds(); + /* sleeping receivers might be excluded by + * stricter permissions. + */ + expunge_all(msq, -EAGAIN); + /* sleeping senders might be able to send + * due to a larger queue size. + */ + ss_wakeup(&msq->q_senders, 0); + break; + default: + err = -EINVAL; + goto out_unlock1; + } + +out_unlock0: + ipc_unlock_object(&msq->q_perm); +out_unlock1: + rcu_read_unlock(); +out_up: + up_write(&msg_ids(ns).rwsem); + return err; +} + +static int msgctl_nolock(struct ipc_namespace *ns, int msqid, + int cmd, int version, void __user *buf) +{ + int err; + struct msg_queue *msq; + + switch (cmd) { + case IPC_INFO: + case MSG_INFO: + { + struct msginfo msginfo; + int max_id; + + if (!buf) + return -EFAULT; + + /* + * We must not return kernel stack data. + * due to padding, it's not enough + * to set all member fields. + */ + err = security_msg_queue_msgctl(NULL, cmd); + if (err) + return err; + + memset(&msginfo, 0, sizeof(msginfo)); + msginfo.msgmni = ns->msg_ctlmni; + msginfo.msgmax = ns->msg_ctlmax; + msginfo.msgmnb = ns->msg_ctlmnb; + msginfo.msgssz = MSGSSZ; + msginfo.msgseg = MSGSEG; + down_read(&msg_ids(ns).rwsem); + if (cmd == MSG_INFO) { + msginfo.msgpool = msg_ids(ns).in_use; + msginfo.msgmap = atomic_read(&ns->msg_hdrs); + msginfo.msgtql = atomic_read(&ns->msg_bytes); + } else { + msginfo.msgmap = MSGMAP; + msginfo.msgpool = MSGPOOL; + msginfo.msgtql = MSGTQL; + } + max_id = ipc_get_maxid(&msg_ids(ns)); + up_read(&msg_ids(ns).rwsem); + if (copy_to_user(buf, &msginfo, sizeof(struct msginfo))) + return -EFAULT; + return (max_id < 0) ? 0 : max_id; + } + + case MSG_STAT: + case IPC_STAT: + { + struct msqid64_ds tbuf; + int success_return; + + if (!buf) + return -EFAULT; + + memset(&tbuf, 0, sizeof(tbuf)); + + rcu_read_lock(); + if (cmd == MSG_STAT) { + msq = msq_obtain_object(ns, msqid); + if (IS_ERR(msq)) { + err = PTR_ERR(msq); + goto out_unlock; + } + success_return = msq->q_perm.id; + } else { + msq = msq_obtain_object_check(ns, msqid); + if (IS_ERR(msq)) { + err = PTR_ERR(msq); + goto out_unlock; + } + success_return = 0; + } + + err = -EACCES; + if (ipcperms(ns, &msq->q_perm, S_IRUGO)) + goto out_unlock; + + err = security_msg_queue_msgctl(msq, cmd); + if (err) + goto out_unlock; + + kernel_to_ipc64_perm(&msq->q_perm, &tbuf.msg_perm); + tbuf.msg_stime = msq->q_stime; + tbuf.msg_rtime = msq->q_rtime; + tbuf.msg_ctime = msq->q_ctime; + tbuf.msg_cbytes = msq->q_cbytes; + tbuf.msg_qnum = msq->q_qnum; + tbuf.msg_qbytes = msq->q_qbytes; + tbuf.msg_lspid = msq->q_lspid; + tbuf.msg_lrpid = msq->q_lrpid; + rcu_read_unlock(); + + if (copy_msqid_to_user(buf, &tbuf, version)) + return -EFAULT; + return success_return; + } + + default: + return -EINVAL; + } + + return err; +out_unlock: + rcu_read_unlock(); + return err; +} + +SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf) +{ + int version; + struct ipc_namespace *ns; + + if (msqid < 0 || cmd < 0) + return -EINVAL; + + version = ipc_parse_version(&cmd); + ns = current->nsproxy->ipc_ns; + + switch (cmd) { + case IPC_INFO: + case MSG_INFO: + case MSG_STAT: /* msqid is an index rather than a msg queue id */ + case IPC_STAT: + return msgctl_nolock(ns, msqid, cmd, version, buf); + case IPC_SET: + case IPC_RMID: + return msgctl_down(ns, msqid, cmd, buf, version); + default: + return -EINVAL; + } +} + +static int testmsg(struct msg_msg *msg, long type, int mode) +{ + switch (mode) { + case SEARCH_ANY: + case SEARCH_NUMBER: + return 1; + case SEARCH_LESSEQUAL: + if (msg->m_type <= type) + return 1; + break; + case SEARCH_EQUAL: + if (msg->m_type == type) + return 1; + break; + case SEARCH_NOTEQUAL: + if (msg->m_type != type) + return 1; + break; + } + return 0; +} + +static inline int pipelined_send(struct msg_queue *msq, struct msg_msg *msg) +{ + struct msg_receiver *msr, *t; + + list_for_each_entry_safe(msr, t, &msq->q_receivers, r_list) { + if (testmsg(msg, msr->r_msgtype, msr->r_mode) && + !security_msg_queue_msgrcv(msq, msg, msr->r_tsk, + msr->r_msgtype, msr->r_mode)) { + /* + * Make sure that the wakeup doesnt preempt + * this CPU prematurely. (on PREEMPT_RT) + */ + preempt_disable_rt(); + + list_del(&msr->r_list); + if (msr->r_maxsize < msg->m_ts) { + /* initialize pipelined send ordering */ + msr->r_msg = NULL; + wake_up_process(msr->r_tsk); + smp_mb(); /* see barrier comment below */ + msr->r_msg = ERR_PTR(-E2BIG); + } else { + msr->r_msg = NULL; + msq->q_lrpid = task_pid_vnr(msr->r_tsk); + msq->q_rtime = get_seconds(); + wake_up_process(msr->r_tsk); + /* + * Ensure that the wakeup is visible before + * setting r_msg, as the receiving end depends + * on it. See lockless receive part 1 and 2 in + * do_msgrcv(). + */ + smp_mb(); + msr->r_msg = msg; + preempt_enable_rt(); + + return 1; + } + preempt_enable_rt(); + } + } + return 0; +} + +long do_msgsnd(int msqid, long mtype, void __user *mtext, + size_t msgsz, int msgflg) +{ + struct msg_queue *msq; + struct msg_msg *msg; + int err; + struct ipc_namespace *ns; + + ns = current->nsproxy->ipc_ns; + + if (msgsz > ns->msg_ctlmax || (long) msgsz < 0 || msqid < 0) + return -EINVAL; + if (mtype < 1) + return -EINVAL; + + msg = load_msg(mtext, msgsz); + if (IS_ERR(msg)) + return PTR_ERR(msg); + + msg->m_type = mtype; + msg->m_ts = msgsz; + + rcu_read_lock(); + msq = msq_obtain_object_check(ns, msqid); + if (IS_ERR(msq)) { + err = PTR_ERR(msq); + goto out_unlock1; + } + + ipc_lock_object(&msq->q_perm); + + for (;;) { + struct msg_sender s; + + err = -EACCES; + if (ipcperms(ns, &msq->q_perm, S_IWUGO)) + goto out_unlock0; + + /* raced with RMID? */ + if (!ipc_valid_object(&msq->q_perm)) { + err = -EIDRM; + goto out_unlock0; + } + + err = security_msg_queue_msgsnd(msq, msg, msgflg); + if (err) + goto out_unlock0; + + if (msgsz + msq->q_cbytes <= msq->q_qbytes && + 1 + msq->q_qnum <= msq->q_qbytes) { + break; + } + + /* queue full, wait: */ + if (msgflg & IPC_NOWAIT) { + err = -EAGAIN; + goto out_unlock0; + } + + /* enqueue the sender and prepare to block */ + ss_add(msq, &s); + + if (!ipc_rcu_getref(msq)) { + err = -EIDRM; + goto out_unlock0; + } + + ipc_unlock_object(&msq->q_perm); + rcu_read_unlock(); + schedule(); + + rcu_read_lock(); + ipc_lock_object(&msq->q_perm); + + ipc_rcu_putref(msq, ipc_rcu_free); + /* raced with RMID? */ + if (!ipc_valid_object(&msq->q_perm)) { + err = -EIDRM; + goto out_unlock0; + } + + ss_del(&s); + + if (signal_pending(current)) { + err = -ERESTARTNOHAND; + goto out_unlock0; + } + + } + msq->q_lspid = task_tgid_vnr(current); + msq->q_stime = get_seconds(); + + if (!pipelined_send(msq, msg)) { + /* no one is waiting for this message, enqueue it */ + list_add_tail(&msg->m_list, &msq->q_messages); + msq->q_cbytes += msgsz; + msq->q_qnum++; + atomic_add(msgsz, &ns->msg_bytes); + atomic_inc(&ns->msg_hdrs); + } + + err = 0; + msg = NULL; + +out_unlock0: + ipc_unlock_object(&msq->q_perm); +out_unlock1: + rcu_read_unlock(); + if (msg != NULL) + free_msg(msg); + return err; +} + +SYSCALL_DEFINE4(msgsnd, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz, + int, msgflg) +{ + long mtype; + + if (get_user(mtype, &msgp->mtype)) + return -EFAULT; + return do_msgsnd(msqid, mtype, msgp->mtext, msgsz, msgflg); +} + +static inline int convert_mode(long *msgtyp, int msgflg) +{ + if (msgflg & MSG_COPY) + return SEARCH_NUMBER; + /* + * find message of correct type. + * msgtyp = 0 => get first. + * msgtyp > 0 => get first message of matching type. + * msgtyp < 0 => get message with least type must be < abs(msgtype). + */ + if (*msgtyp == 0) + return SEARCH_ANY; + if (*msgtyp < 0) { + *msgtyp = -*msgtyp; + return SEARCH_LESSEQUAL; + } + if (msgflg & MSG_EXCEPT) + return SEARCH_NOTEQUAL; + return SEARCH_EQUAL; +} + +static long do_msg_fill(void __user *dest, struct msg_msg *msg, size_t bufsz) +{ + struct msgbuf __user *msgp = dest; + size_t msgsz; + + if (put_user(msg->m_type, &msgp->mtype)) + return -EFAULT; + + msgsz = (bufsz > msg->m_ts) ? msg->m_ts : bufsz; + if (store_msg(msgp->mtext, msg, msgsz)) + return -EFAULT; + return msgsz; +} + +#ifdef CONFIG_CHECKPOINT_RESTORE +/* + * This function creates new kernel message structure, large enough to store + * bufsz message bytes. + */ +static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz) +{ + struct msg_msg *copy; + + /* + * Create dummy message to copy real message to. + */ + copy = load_msg(buf, bufsz); + if (!IS_ERR(copy)) + copy->m_ts = bufsz; + return copy; +} + +static inline void free_copy(struct msg_msg *copy) +{ + if (copy) + free_msg(copy); +} +#else +static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz) +{ + return ERR_PTR(-ENOSYS); +} + +static inline void free_copy(struct msg_msg *copy) +{ +} +#endif + +static struct msg_msg *find_msg(struct msg_queue *msq, long *msgtyp, int mode) +{ + struct msg_msg *msg, *found = NULL; + long count = 0; + + list_for_each_entry(msg, &msq->q_messages, m_list) { + if (testmsg(msg, *msgtyp, mode) && + !security_msg_queue_msgrcv(msq, msg, current, + *msgtyp, mode)) { + if (mode == SEARCH_LESSEQUAL && msg->m_type != 1) { + *msgtyp = msg->m_type - 1; + found = msg; + } else if (mode == SEARCH_NUMBER) { + if (*msgtyp == count) + return msg; + } else + return msg; + count++; + } + } + + return found ?: ERR_PTR(-EAGAIN); +} + +long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp, int msgflg, + long (*msg_handler)(void __user *, struct msg_msg *, size_t)) +{ + int mode; + struct msg_queue *msq; + struct ipc_namespace *ns; + struct msg_msg *msg, *copy = NULL; + + ns = current->nsproxy->ipc_ns; + + if (msqid < 0 || (long) bufsz < 0) + return -EINVAL; + + if (msgflg & MSG_COPY) { + if ((msgflg & MSG_EXCEPT) || !(msgflg & IPC_NOWAIT)) + return -EINVAL; + copy = prepare_copy(buf, min_t(size_t, bufsz, ns->msg_ctlmax)); + if (IS_ERR(copy)) + return PTR_ERR(copy); + } + mode = convert_mode(&msgtyp, msgflg); + + rcu_read_lock(); + msq = msq_obtain_object_check(ns, msqid); + if (IS_ERR(msq)) { + rcu_read_unlock(); + free_copy(copy); + return PTR_ERR(msq); + } + + for (;;) { + struct msg_receiver msr_d; + + msg = ERR_PTR(-EACCES); + if (ipcperms(ns, &msq->q_perm, S_IRUGO)) + goto out_unlock1; + + ipc_lock_object(&msq->q_perm); + + /* raced with RMID? */ + if (!ipc_valid_object(&msq->q_perm)) { + msg = ERR_PTR(-EIDRM); + goto out_unlock0; + } + + msg = find_msg(msq, &msgtyp, mode); + if (!IS_ERR(msg)) { + /* + * Found a suitable message. + * Unlink it from the queue. + */ + if ((bufsz < msg->m_ts) && !(msgflg & MSG_NOERROR)) { + msg = ERR_PTR(-E2BIG); + goto out_unlock0; + } + /* + * If we are copying, then do not unlink message and do + * not update queue parameters. + */ + if (msgflg & MSG_COPY) { + msg = copy_msg(msg, copy); + goto out_unlock0; + } + + list_del(&msg->m_list); + msq->q_qnum--; + msq->q_rtime = get_seconds(); + msq->q_lrpid = task_tgid_vnr(current); + msq->q_cbytes -= msg->m_ts; + atomic_sub(msg->m_ts, &ns->msg_bytes); + atomic_dec(&ns->msg_hdrs); + ss_wakeup(&msq->q_senders, 0); + + goto out_unlock0; + } + + /* No message waiting. Wait for a message */ + if (msgflg & IPC_NOWAIT) { + msg = ERR_PTR(-ENOMSG); + goto out_unlock0; + } + + list_add_tail(&msr_d.r_list, &msq->q_receivers); + msr_d.r_tsk = current; + msr_d.r_msgtype = msgtyp; + msr_d.r_mode = mode; + if (msgflg & MSG_NOERROR) + msr_d.r_maxsize = INT_MAX; + else + msr_d.r_maxsize = bufsz; + msr_d.r_msg = ERR_PTR(-EAGAIN); + __set_current_state(TASK_INTERRUPTIBLE); + + ipc_unlock_object(&msq->q_perm); + rcu_read_unlock(); + schedule(); + + /* Lockless receive, part 1: + * Disable preemption. We don't hold a reference to the queue + * and getting a reference would defeat the idea of a lockless + * operation, thus the code relies on rcu to guarantee the + * existence of msq: + * Prior to destruction, expunge_all(-EIRDM) changes r_msg. + * Thus if r_msg is -EAGAIN, then the queue not yet destroyed. + * rcu_read_lock() prevents preemption between reading r_msg + * and acquiring the q_perm.lock in ipc_lock_object(). + */ + rcu_read_lock(); + + /* Lockless receive, part 2: + * Wait until pipelined_send or expunge_all are outside of + * wake_up_process(). There is a race with exit(), see + * ipc/mqueue.c for the details. + */ + msg = (struct msg_msg *)msr_d.r_msg; + while (msg == NULL) { + cpu_relax(); + msg = (struct msg_msg *)msr_d.r_msg; + } + + /* Lockless receive, part 3: + * If there is a message or an error then accept it without + * locking. + */ + if (msg != ERR_PTR(-EAGAIN)) + goto out_unlock1; + + /* Lockless receive, part 3: + * Acquire the queue spinlock. + */ + ipc_lock_object(&msq->q_perm); + + /* Lockless receive, part 4: + * Repeat test after acquiring the spinlock. + */ + msg = (struct msg_msg *)msr_d.r_msg; + if (msg != ERR_PTR(-EAGAIN)) + goto out_unlock0; + + list_del(&msr_d.r_list); + if (signal_pending(current)) { + msg = ERR_PTR(-ERESTARTNOHAND); + goto out_unlock0; + } + + ipc_unlock_object(&msq->q_perm); + } + +out_unlock0: + ipc_unlock_object(&msq->q_perm); +out_unlock1: + rcu_read_unlock(); + if (IS_ERR(msg)) { + free_copy(copy); + return PTR_ERR(msg); + } + + bufsz = msg_handler(buf, msg, bufsz); + free_msg(msg); + + return bufsz; +} + +SYSCALL_DEFINE5(msgrcv, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz, + long, msgtyp, int, msgflg) +{ + return do_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg, do_msg_fill); +} + + +void msg_init_ns(struct ipc_namespace *ns) +{ + ns->msg_ctlmax = MSGMAX; + ns->msg_ctlmnb = MSGMNB; + ns->msg_ctlmni = MSGMNI; + + atomic_set(&ns->msg_bytes, 0); + atomic_set(&ns->msg_hdrs, 0); + ipc_init_ids(&ns->ids[IPC_MSG_IDS]); +} + +#ifdef CONFIG_IPC_NS +void msg_exit_ns(struct ipc_namespace *ns) +{ + free_ipcs(ns, &msg_ids(ns), freeque); + idr_destroy(&ns->ids[IPC_MSG_IDS].ipcs_idr); +} +#endif + +#ifdef CONFIG_PROC_FS +static int sysvipc_msg_proc_show(struct seq_file *s, void *it) +{ + struct user_namespace *user_ns = seq_user_ns(s); + struct msg_queue *msq = it; + + seq_printf(s, + "%10d %10d %4o %10lu %10lu %5u %5u %5u %5u %5u %5u %10lu %10lu %10lu\n", + msq->q_perm.key, + msq->q_perm.id, + msq->q_perm.mode, + msq->q_cbytes, + msq->q_qnum, + msq->q_lspid, + msq->q_lrpid, + from_kuid_munged(user_ns, msq->q_perm.uid), + from_kgid_munged(user_ns, msq->q_perm.gid), + from_kuid_munged(user_ns, msq->q_perm.cuid), + from_kgid_munged(user_ns, msq->q_perm.cgid), + msq->q_stime, + msq->q_rtime, + msq->q_ctime); + + return 0; +} +#endif + +void __init msg_init(void) +{ + msg_init_ns(&init_ipc_ns); + + ipc_init_proc_interface("sysvipc/msg", + " key msqid perms cbytes qnum lspid lrpid uid gid cuid cgid stime rtime ctime\n", + IPC_MSG_IDS, sysvipc_msg_proc_show); +} diff --git a/kernel/ipc/msgutil.c b/kernel/ipc/msgutil.c new file mode 100644 index 000000000..2b491590e --- /dev/null +++ b/kernel/ipc/msgutil.c @@ -0,0 +1,185 @@ +/* + * linux/ipc/msgutil.c + * Copyright (C) 1999, 2004 Manfred Spraul + * + * This file is released under GNU General Public Licence version 2 or + * (at your option) any later version. + * + * See the file COPYING for more details. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "util.h" + +DEFINE_SPINLOCK(mq_lock); + +/* + * The next 2 defines are here bc this is the only file + * compiled when either CONFIG_SYSVIPC and CONFIG_POSIX_MQUEUE + * and not CONFIG_IPC_NS. + */ +struct ipc_namespace init_ipc_ns = { + .count = ATOMIC_INIT(1), + .user_ns = &init_user_ns, + .ns.inum = PROC_IPC_INIT_INO, +#ifdef CONFIG_IPC_NS + .ns.ops = &ipcns_operations, +#endif +}; + +atomic_t nr_ipc_ns = ATOMIC_INIT(1); + +struct msg_msgseg { + struct msg_msgseg *next; + /* the next part of the message follows immediately */ +}; + +#define DATALEN_MSG ((size_t)PAGE_SIZE-sizeof(struct msg_msg)) +#define DATALEN_SEG ((size_t)PAGE_SIZE-sizeof(struct msg_msgseg)) + + +static struct msg_msg *alloc_msg(size_t len) +{ + struct msg_msg *msg; + struct msg_msgseg **pseg; + size_t alen; + + alen = min(len, DATALEN_MSG); + msg = kmalloc(sizeof(*msg) + alen, GFP_KERNEL); + if (msg == NULL) + return NULL; + + msg->next = NULL; + msg->security = NULL; + + len -= alen; + pseg = &msg->next; + while (len > 0) { + struct msg_msgseg *seg; + alen = min(len, DATALEN_SEG); + seg = kmalloc(sizeof(*seg) + alen, GFP_KERNEL); + if (seg == NULL) + goto out_err; + *pseg = seg; + seg->next = NULL; + pseg = &seg->next; + len -= alen; + } + + return msg; + +out_err: + free_msg(msg); + return NULL; +} + +struct msg_msg *load_msg(const void __user *src, size_t len) +{ + struct msg_msg *msg; + struct msg_msgseg *seg; + int err = -EFAULT; + size_t alen; + + msg = alloc_msg(len); + if (msg == NULL) + return ERR_PTR(-ENOMEM); + + alen = min(len, DATALEN_MSG); + if (copy_from_user(msg + 1, src, alen)) + goto out_err; + + for (seg = msg->next; seg != NULL; seg = seg->next) { + len -= alen; + src = (char __user *)src + alen; + alen = min(len, DATALEN_SEG); + if (copy_from_user(seg + 1, src, alen)) + goto out_err; + } + + err = security_msg_msg_alloc(msg); + if (err) + goto out_err; + + return msg; + +out_err: + free_msg(msg); + return ERR_PTR(err); +} +#ifdef CONFIG_CHECKPOINT_RESTORE +struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst) +{ + struct msg_msgseg *dst_pseg, *src_pseg; + size_t len = src->m_ts; + size_t alen; + + BUG_ON(dst == NULL); + if (src->m_ts > dst->m_ts) + return ERR_PTR(-EINVAL); + + alen = min(len, DATALEN_MSG); + memcpy(dst + 1, src + 1, alen); + + for (dst_pseg = dst->next, src_pseg = src->next; + src_pseg != NULL; + dst_pseg = dst_pseg->next, src_pseg = src_pseg->next) { + + len -= alen; + alen = min(len, DATALEN_SEG); + memcpy(dst_pseg + 1, src_pseg + 1, alen); + } + + dst->m_type = src->m_type; + dst->m_ts = src->m_ts; + + return dst; +} +#else +struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst) +{ + return ERR_PTR(-ENOSYS); +} +#endif +int store_msg(void __user *dest, struct msg_msg *msg, size_t len) +{ + size_t alen; + struct msg_msgseg *seg; + + alen = min(len, DATALEN_MSG); + if (copy_to_user(dest, msg + 1, alen)) + return -1; + + for (seg = msg->next; seg != NULL; seg = seg->next) { + len -= alen; + dest = (char __user *)dest + alen; + alen = min(len, DATALEN_SEG); + if (copy_to_user(dest, seg + 1, alen)) + return -1; + } + return 0; +} + +void free_msg(struct msg_msg *msg) +{ + struct msg_msgseg *seg; + + security_msg_msg_free(msg); + + seg = msg->next; + kfree(msg); + while (seg != NULL) { + struct msg_msgseg *tmp = seg->next; + kfree(seg); + seg = tmp; + } +} diff --git a/kernel/ipc/namespace.c b/kernel/ipc/namespace.c new file mode 100644 index 000000000..068caf18d --- /dev/null +++ b/kernel/ipc/namespace.c @@ -0,0 +1,175 @@ +/* + * linux/ipc/namespace.c + * Copyright (C) 2006 Pavel Emelyanov OpenVZ, SWsoft Inc. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "util.h" + +static struct ipc_namespace *create_ipc_ns(struct user_namespace *user_ns, + struct ipc_namespace *old_ns) +{ + struct ipc_namespace *ns; + int err; + + ns = kmalloc(sizeof(struct ipc_namespace), GFP_KERNEL); + if (ns == NULL) + return ERR_PTR(-ENOMEM); + + err = ns_alloc_inum(&ns->ns); + if (err) { + kfree(ns); + return ERR_PTR(err); + } + ns->ns.ops = &ipcns_operations; + + atomic_set(&ns->count, 1); + err = mq_init_ns(ns); + if (err) { + ns_free_inum(&ns->ns); + kfree(ns); + return ERR_PTR(err); + } + atomic_inc(&nr_ipc_ns); + + sem_init_ns(ns); + msg_init_ns(ns); + shm_init_ns(ns); + + ns->user_ns = get_user_ns(user_ns); + + return ns; +} + +struct ipc_namespace *copy_ipcs(unsigned long flags, + struct user_namespace *user_ns, struct ipc_namespace *ns) +{ + if (!(flags & CLONE_NEWIPC)) + return get_ipc_ns(ns); + return create_ipc_ns(user_ns, ns); +} + +/* + * free_ipcs - free all ipcs of one type + * @ns: the namespace to remove the ipcs from + * @ids: the table of ipcs to free + * @free: the function called to free each individual ipc + * + * Called for each kind of ipc when an ipc_namespace exits. + */ +void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids, + void (*free)(struct ipc_namespace *, struct kern_ipc_perm *)) +{ + struct kern_ipc_perm *perm; + int next_id; + int total, in_use; + + down_write(&ids->rwsem); + + in_use = ids->in_use; + + for (total = 0, next_id = 0; total < in_use; next_id++) { + perm = idr_find(&ids->ipcs_idr, next_id); + if (perm == NULL) + continue; + rcu_read_lock(); + ipc_lock_object(perm); + free(ns, perm); + total++; + } + up_write(&ids->rwsem); +} + +static void free_ipc_ns(struct ipc_namespace *ns) +{ + sem_exit_ns(ns); + msg_exit_ns(ns); + shm_exit_ns(ns); + atomic_dec(&nr_ipc_ns); + + put_user_ns(ns->user_ns); + ns_free_inum(&ns->ns); + kfree(ns); +} + +/* + * put_ipc_ns - drop a reference to an ipc namespace. + * @ns: the namespace to put + * + * If this is the last task in the namespace exiting, and + * it is dropping the refcount to 0, then it can race with + * a task in another ipc namespace but in a mounts namespace + * which has this ipcns's mqueuefs mounted, doing some action + * with one of the mqueuefs files. That can raise the refcount. + * So dropping the refcount, and raising the refcount when + * accessing it through the VFS, are protected with mq_lock. + * + * (Clearly, a task raising the refcount on its own ipc_ns + * needn't take mq_lock since it can't race with the last task + * in the ipcns exiting). + */ +void put_ipc_ns(struct ipc_namespace *ns) +{ + if (atomic_dec_and_lock(&ns->count, &mq_lock)) { + mq_clear_sbinfo(ns); + spin_unlock(&mq_lock); + mq_put_mnt(ns); + free_ipc_ns(ns); + } +} + +static inline struct ipc_namespace *to_ipc_ns(struct ns_common *ns) +{ + return container_of(ns, struct ipc_namespace, ns); +} + +static struct ns_common *ipcns_get(struct task_struct *task) +{ + struct ipc_namespace *ns = NULL; + struct nsproxy *nsproxy; + + task_lock(task); + nsproxy = task->nsproxy; + if (nsproxy) + ns = get_ipc_ns(nsproxy->ipc_ns); + task_unlock(task); + + return ns ? &ns->ns : NULL; +} + +static void ipcns_put(struct ns_common *ns) +{ + return put_ipc_ns(to_ipc_ns(ns)); +} + +static int ipcns_install(struct nsproxy *nsproxy, struct ns_common *new) +{ + struct ipc_namespace *ns = to_ipc_ns(new); + if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN) || + !ns_capable(current_user_ns(), CAP_SYS_ADMIN)) + return -EPERM; + + /* Ditch state from the old ipc namespace */ + exit_sem(current); + put_ipc_ns(nsproxy->ipc_ns); + nsproxy->ipc_ns = get_ipc_ns(ns); + return 0; +} + +const struct proc_ns_operations ipcns_operations = { + .name = "ipc", + .type = CLONE_NEWIPC, + .get = ipcns_get, + .put = ipcns_put, + .install = ipcns_install, +}; diff --git a/kernel/ipc/sem.c b/kernel/ipc/sem.c new file mode 100644 index 000000000..8f99bac19 --- /dev/null +++ b/kernel/ipc/sem.c @@ -0,0 +1,2198 @@ +/* + * linux/ipc/sem.c + * Copyright (C) 1992 Krishna Balasubramanian + * Copyright (C) 1995 Eric Schenk, Bruno Haible + * + * /proc/sysvipc/sem support (c) 1999 Dragos Acostachioaie + * + * SMP-threaded, sysctl's added + * (c) 1999 Manfred Spraul + * Enforced range limit on SEM_UNDO + * (c) 2001 Red Hat Inc + * Lockless wakeup + * (c) 2003 Manfred Spraul + * Further wakeup optimizations, documentation + * (c) 2010 Manfred Spraul + * + * support for audit of ipc object properties and permission changes + * Dustin Kirkland + * + * namespaces support + * OpenVZ, SWsoft Inc. + * Pavel Emelianov + * + * Implementation notes: (May 2010) + * This file implements System V semaphores. + * + * User space visible behavior: + * - FIFO ordering for semop() operations (just FIFO, not starvation + * protection) + * - multiple semaphore operations that alter the same semaphore in + * one semop() are handled. + * - sem_ctime (time of last semctl()) is updated in the IPC_SET, SETVAL and + * SETALL calls. + * - two Linux specific semctl() commands: SEM_STAT, SEM_INFO. + * - undo adjustments at process exit are limited to 0..SEMVMX. + * - namespace are supported. + * - SEMMSL, SEMMNS, SEMOPM and SEMMNI can be configured at runtine by writing + * to /proc/sys/kernel/sem. + * - statistics about the usage are reported in /proc/sysvipc/sem. + * + * Internals: + * - scalability: + * - all global variables are read-mostly. + * - semop() calls and semctl(RMID) are synchronized by RCU. + * - most operations do write operations (actually: spin_lock calls) to + * the per-semaphore array structure. + * Thus: Perfect SMP scaling between independent semaphore arrays. + * If multiple semaphores in one array are used, then cache line + * trashing on the semaphore array spinlock will limit the scaling. + * - semncnt and semzcnt are calculated on demand in count_semcnt() + * - the task that performs a successful semop() scans the list of all + * sleeping tasks and completes any pending operations that can be fulfilled. + * Semaphores are actively given to waiting tasks (necessary for FIFO). + * (see update_queue()) + * - To improve the scalability, the actual wake-up calls are performed after + * dropping all locks. (see wake_up_sem_queue_prepare(), + * wake_up_sem_queue_do()) + * - All work is done by the waker, the woken up task does not have to do + * anything - not even acquiring a lock or dropping a refcount. + * - A woken up task may not even touch the semaphore array anymore, it may + * have been destroyed already by a semctl(RMID). + * - The synchronizations between wake-ups due to a timeout/signal and a + * wake-up due to a completed semaphore operation is achieved by using an + * intermediate state (IN_WAKEUP). + * - UNDO values are stored in an array (one per process and per + * semaphore array, lazily allocated). For backwards compatibility, multiple + * modes for the UNDO variables are supported (per process, per thread) + * (see copy_semundo, CLONE_SYSVSEM) + * - There are two lists of the pending operations: a per-array list + * and per-semaphore list (stored in the array). This allows to achieve FIFO + * ordering without always scanning all pending operations. + * The worst-case behavior is nevertheless O(N^2) for N wakeups. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include "util.h" + +/* One semaphore structure for each semaphore in the system. */ +struct sem { + int semval; /* current value */ + int sempid; /* pid of last operation */ + spinlock_t lock; /* spinlock for fine-grained semtimedop */ + struct list_head pending_alter; /* pending single-sop operations */ + /* that alter the semaphore */ + struct list_head pending_const; /* pending single-sop operations */ + /* that do not alter the semaphore*/ + time_t sem_otime; /* candidate for sem_otime */ +} ____cacheline_aligned_in_smp; + +/* One queue for each sleeping process in the system. */ +struct sem_queue { + struct list_head list; /* queue of pending operations */ + struct task_struct *sleeper; /* this process */ + struct sem_undo *undo; /* undo structure */ + int pid; /* process id of requesting process */ + int status; /* completion status of operation */ + struct sembuf *sops; /* array of pending operations */ + struct sembuf *blocking; /* the operation that blocked */ + int nsops; /* number of operations */ + int alter; /* does *sops alter the array? */ +}; + +/* Each task has a list of undo requests. They are executed automatically + * when the process exits. + */ +struct sem_undo { + struct list_head list_proc; /* per-process list: * + * all undos from one process + * rcu protected */ + struct rcu_head rcu; /* rcu struct for sem_undo */ + struct sem_undo_list *ulp; /* back ptr to sem_undo_list */ + struct list_head list_id; /* per semaphore array list: + * all undos for one array */ + int semid; /* semaphore set identifier */ + short *semadj; /* array of adjustments */ + /* one per semaphore */ +}; + +/* sem_undo_list controls shared access to the list of sem_undo structures + * that may be shared among all a CLONE_SYSVSEM task group. + */ +struct sem_undo_list { + atomic_t refcnt; + spinlock_t lock; + struct list_head list_proc; +}; + + +#define sem_ids(ns) ((ns)->ids[IPC_SEM_IDS]) + +#define sem_checkid(sma, semid) ipc_checkid(&sma->sem_perm, semid) + +static int newary(struct ipc_namespace *, struct ipc_params *); +static void freeary(struct ipc_namespace *, struct kern_ipc_perm *); +#ifdef CONFIG_PROC_FS +static int sysvipc_sem_proc_show(struct seq_file *s, void *it); +#endif + +#define SEMMSL_FAST 256 /* 512 bytes on stack */ +#define SEMOPM_FAST 64 /* ~ 372 bytes on stack */ + +/* + * Locking: + * sem_undo.id_next, + * sem_array.complex_count, + * sem_array.pending{_alter,_cont}, + * sem_array.sem_undo: global sem_lock() for read/write + * sem_undo.proc_next: only "current" is allowed to read/write that field. + * + * sem_array.sem_base[i].pending_{const,alter}: + * global or semaphore sem_lock() for read/write + */ + +#define sc_semmsl sem_ctls[0] +#define sc_semmns sem_ctls[1] +#define sc_semopm sem_ctls[2] +#define sc_semmni sem_ctls[3] + +void sem_init_ns(struct ipc_namespace *ns) +{ + ns->sc_semmsl = SEMMSL; + ns->sc_semmns = SEMMNS; + ns->sc_semopm = SEMOPM; + ns->sc_semmni = SEMMNI; + ns->used_sems = 0; + ipc_init_ids(&ns->ids[IPC_SEM_IDS]); +} + +#ifdef CONFIG_IPC_NS +void sem_exit_ns(struct ipc_namespace *ns) +{ + free_ipcs(ns, &sem_ids(ns), freeary); + idr_destroy(&ns->ids[IPC_SEM_IDS].ipcs_idr); +} +#endif + +void __init sem_init(void) +{ + sem_init_ns(&init_ipc_ns); + ipc_init_proc_interface("sysvipc/sem", + " key semid perms nsems uid gid cuid cgid otime ctime\n", + IPC_SEM_IDS, sysvipc_sem_proc_show); +} + +/** + * unmerge_queues - unmerge queues, if possible. + * @sma: semaphore array + * + * The function unmerges the wait queues if complex_count is 0. + * It must be called prior to dropping the global semaphore array lock. + */ +static void unmerge_queues(struct sem_array *sma) +{ + struct sem_queue *q, *tq; + + /* complex operations still around? */ + if (sma->complex_count) + return; + /* + * We will switch back to simple mode. + * Move all pending operation back into the per-semaphore + * queues. + */ + list_for_each_entry_safe(q, tq, &sma->pending_alter, list) { + struct sem *curr; + curr = &sma->sem_base[q->sops[0].sem_num]; + + list_add_tail(&q->list, &curr->pending_alter); + } + INIT_LIST_HEAD(&sma->pending_alter); +} + +/** + * merge_queues - merge single semop queues into global queue + * @sma: semaphore array + * + * This function merges all per-semaphore queues into the global queue. + * It is necessary to achieve FIFO ordering for the pending single-sop + * operations when a multi-semop operation must sleep. + * Only the alter operations must be moved, the const operations can stay. + */ +static void merge_queues(struct sem_array *sma) +{ + int i; + for (i = 0; i < sma->sem_nsems; i++) { + struct sem *sem = sma->sem_base + i; + + list_splice_init(&sem->pending_alter, &sma->pending_alter); + } +} + +static void sem_rcu_free(struct rcu_head *head) +{ + struct ipc_rcu *p = container_of(head, struct ipc_rcu, rcu); + struct sem_array *sma = ipc_rcu_to_struct(p); + + security_sem_free(sma); + ipc_rcu_free(head); +} + +/* + * Wait until all currently ongoing simple ops have completed. + * Caller must own sem_perm.lock. + * New simple ops cannot start, because simple ops first check + * that sem_perm.lock is free. + * that a) sem_perm.lock is free and b) complex_count is 0. + */ +static void sem_wait_array(struct sem_array *sma) +{ + int i; + struct sem *sem; + + if (sma->complex_count) { + /* The thread that increased sma->complex_count waited on + * all sem->lock locks. Thus we don't need to wait again. + */ + return; + } + + for (i = 0; i < sma->sem_nsems; i++) { + sem = sma->sem_base + i; + spin_unlock_wait(&sem->lock); + } +} + +/* + * If the request contains only one semaphore operation, and there are + * no complex transactions pending, lock only the semaphore involved. + * Otherwise, lock the entire semaphore array, since we either have + * multiple semaphores in our own semops, or we need to look at + * semaphores from other pending complex operations. + */ +static inline int sem_lock(struct sem_array *sma, struct sembuf *sops, + int nsops) +{ + struct sem *sem; + + if (nsops != 1) { + /* Complex operation - acquire a full lock */ + ipc_lock_object(&sma->sem_perm); + + /* And wait until all simple ops that are processed + * right now have dropped their locks. + */ + sem_wait_array(sma); + return -1; + } + + /* + * Only one semaphore affected - try to optimize locking. + * The rules are: + * - optimized locking is possible if no complex operation + * is either enqueued or processed right now. + * - The test for enqueued complex ops is simple: + * sma->complex_count != 0 + * - Testing for complex ops that are processed right now is + * a bit more difficult. Complex ops acquire the full lock + * and first wait that the running simple ops have completed. + * (see above) + * Thus: If we own a simple lock and the global lock is free + * and complex_count is now 0, then it will stay 0 and + * thus just locking sem->lock is sufficient. + */ + sem = sma->sem_base + sops->sem_num; + + if (sma->complex_count == 0) { + /* + * It appears that no complex operation is around. + * Acquire the per-semaphore lock. + */ + spin_lock(&sem->lock); + + /* Then check that the global lock is free */ + if (!spin_is_locked(&sma->sem_perm.lock)) { + /* + * The ipc object lock check must be visible on all + * cores before rechecking the complex count. Otherwise + * we can race with another thread that does: + * complex_count++; + * spin_unlock(sem_perm.lock); + */ + smp_rmb(); + + /* + * Now repeat the test of complex_count: + * It can't change anymore until we drop sem->lock. + * Thus: if is now 0, then it will stay 0. + */ + if (sma->complex_count == 0) { + /* fast path successful! */ + return sops->sem_num; + } + } + spin_unlock(&sem->lock); + } + + /* slow path: acquire the full lock */ + ipc_lock_object(&sma->sem_perm); + + if (sma->complex_count == 0) { + /* False alarm: + * There is no complex operation, thus we can switch + * back to the fast path. + */ + spin_lock(&sem->lock); + ipc_unlock_object(&sma->sem_perm); + return sops->sem_num; + } else { + /* Not a false alarm, thus complete the sequence for a + * full lock. + */ + sem_wait_array(sma); + return -1; + } +} + +static inline void sem_unlock(struct sem_array *sma, int locknum) +{ + if (locknum == -1) { + unmerge_queues(sma); + ipc_unlock_object(&sma->sem_perm); + } else { + struct sem *sem = sma->sem_base + locknum; + spin_unlock(&sem->lock); + } +} + +/* + * sem_lock_(check_) routines are called in the paths where the rwsem + * is not held. + * + * The caller holds the RCU read lock. + */ +static inline struct sem_array *sem_obtain_lock(struct ipc_namespace *ns, + int id, struct sembuf *sops, int nsops, int *locknum) +{ + struct kern_ipc_perm *ipcp; + struct sem_array *sma; + + ipcp = ipc_obtain_object(&sem_ids(ns), id); + if (IS_ERR(ipcp)) + return ERR_CAST(ipcp); + + sma = container_of(ipcp, struct sem_array, sem_perm); + *locknum = sem_lock(sma, sops, nsops); + + /* ipc_rmid() may have already freed the ID while sem_lock + * was spinning: verify that the structure is still valid + */ + if (ipc_valid_object(ipcp)) + return container_of(ipcp, struct sem_array, sem_perm); + + sem_unlock(sma, *locknum); + return ERR_PTR(-EINVAL); +} + +static inline struct sem_array *sem_obtain_object(struct ipc_namespace *ns, int id) +{ + struct kern_ipc_perm *ipcp = ipc_obtain_object(&sem_ids(ns), id); + + if (IS_ERR(ipcp)) + return ERR_CAST(ipcp); + + return container_of(ipcp, struct sem_array, sem_perm); +} + +static inline struct sem_array *sem_obtain_object_check(struct ipc_namespace *ns, + int id) +{ + struct kern_ipc_perm *ipcp = ipc_obtain_object_check(&sem_ids(ns), id); + + if (IS_ERR(ipcp)) + return ERR_CAST(ipcp); + + return container_of(ipcp, struct sem_array, sem_perm); +} + +static inline void sem_lock_and_putref(struct sem_array *sma) +{ + sem_lock(sma, NULL, -1); + ipc_rcu_putref(sma, ipc_rcu_free); +} + +static inline void sem_rmid(struct ipc_namespace *ns, struct sem_array *s) +{ + ipc_rmid(&sem_ids(ns), &s->sem_perm); +} + +/* + * Lockless wakeup algorithm: + * Without the check/retry algorithm a lockless wakeup is possible: + * - queue.status is initialized to -EINTR before blocking. + * - wakeup is performed by + * * unlinking the queue entry from the pending list + * * setting queue.status to IN_WAKEUP + * This is the notification for the blocked thread that a + * result value is imminent. + * * call wake_up_process + * * set queue.status to the final value. + * - the previously blocked thread checks queue.status: + * * if it's IN_WAKEUP, then it must wait until the value changes + * * if it's not -EINTR, then the operation was completed by + * update_queue. semtimedop can return queue.status without + * performing any operation on the sem array. + * * otherwise it must acquire the spinlock and check what's up. + * + * The two-stage algorithm is necessary to protect against the following + * races: + * - if queue.status is set after wake_up_process, then the woken up idle + * thread could race forward and try (and fail) to acquire sma->lock + * before update_queue had a chance to set queue.status + * - if queue.status is written before wake_up_process and if the + * blocked process is woken up by a signal between writing + * queue.status and the wake_up_process, then the woken up + * process could return from semtimedop and die by calling + * sys_exit before wake_up_process is called. Then wake_up_process + * will oops, because the task structure is already invalid. + * (yes, this happened on s390 with sysv msg). + * + */ +#define IN_WAKEUP 1 + +/** + * newary - Create a new semaphore set + * @ns: namespace + * @params: ptr to the structure that contains key, semflg and nsems + * + * Called with sem_ids.rwsem held (as a writer) + */ +static int newary(struct ipc_namespace *ns, struct ipc_params *params) +{ + int id; + int retval; + struct sem_array *sma; + int size; + key_t key = params->key; + int nsems = params->u.nsems; + int semflg = params->flg; + int i; + + if (!nsems) + return -EINVAL; + if (ns->used_sems + nsems > ns->sc_semmns) + return -ENOSPC; + + size = sizeof(*sma) + nsems * sizeof(struct sem); + sma = ipc_rcu_alloc(size); + if (!sma) + return -ENOMEM; + + memset(sma, 0, size); + + sma->sem_perm.mode = (semflg & S_IRWXUGO); + sma->sem_perm.key = key; + + sma->sem_perm.security = NULL; + retval = security_sem_alloc(sma); + if (retval) { + ipc_rcu_putref(sma, ipc_rcu_free); + return retval; + } + + sma->sem_base = (struct sem *) &sma[1]; + + for (i = 0; i < nsems; i++) { + INIT_LIST_HEAD(&sma->sem_base[i].pending_alter); + INIT_LIST_HEAD(&sma->sem_base[i].pending_const); + spin_lock_init(&sma->sem_base[i].lock); + } + + sma->complex_count = 0; + INIT_LIST_HEAD(&sma->pending_alter); + INIT_LIST_HEAD(&sma->pending_const); + INIT_LIST_HEAD(&sma->list_id); + sma->sem_nsems = nsems; + sma->sem_ctime = get_seconds(); + + id = ipc_addid(&sem_ids(ns), &sma->sem_perm, ns->sc_semmni); + if (id < 0) { + ipc_rcu_putref(sma, sem_rcu_free); + return id; + } + ns->used_sems += nsems; + + sem_unlock(sma, -1); + rcu_read_unlock(); + + return sma->sem_perm.id; +} + + +/* + * Called with sem_ids.rwsem and ipcp locked. + */ +static inline int sem_security(struct kern_ipc_perm *ipcp, int semflg) +{ + struct sem_array *sma; + + sma = container_of(ipcp, struct sem_array, sem_perm); + return security_sem_associate(sma, semflg); +} + +/* + * Called with sem_ids.rwsem and ipcp locked. + */ +static inline int sem_more_checks(struct kern_ipc_perm *ipcp, + struct ipc_params *params) +{ + struct sem_array *sma; + + sma = container_of(ipcp, struct sem_array, sem_perm); + if (params->u.nsems > sma->sem_nsems) + return -EINVAL; + + return 0; +} + +SYSCALL_DEFINE3(semget, key_t, key, int, nsems, int, semflg) +{ + struct ipc_namespace *ns; + static const struct ipc_ops sem_ops = { + .getnew = newary, + .associate = sem_security, + .more_checks = sem_more_checks, + }; + struct ipc_params sem_params; + + ns = current->nsproxy->ipc_ns; + + if (nsems < 0 || nsems > ns->sc_semmsl) + return -EINVAL; + + sem_params.key = key; + sem_params.flg = semflg; + sem_params.u.nsems = nsems; + + return ipcget(ns, &sem_ids(ns), &sem_ops, &sem_params); +} + +/** + * perform_atomic_semop - Perform (if possible) a semaphore operation + * @sma: semaphore array + * @q: struct sem_queue that describes the operation + * + * Returns 0 if the operation was possible. + * Returns 1 if the operation is impossible, the caller must sleep. + * Negative values are error codes. + */ +static int perform_atomic_semop(struct sem_array *sma, struct sem_queue *q) +{ + int result, sem_op, nsops, pid; + struct sembuf *sop; + struct sem *curr; + struct sembuf *sops; + struct sem_undo *un; + + sops = q->sops; + nsops = q->nsops; + un = q->undo; + + for (sop = sops; sop < sops + nsops; sop++) { + curr = sma->sem_base + sop->sem_num; + sem_op = sop->sem_op; + result = curr->semval; + + if (!sem_op && result) + goto would_block; + + result += sem_op; + if (result < 0) + goto would_block; + if (result > SEMVMX) + goto out_of_range; + + if (sop->sem_flg & SEM_UNDO) { + int undo = un->semadj[sop->sem_num] - sem_op; + /* Exceeding the undo range is an error. */ + if (undo < (-SEMAEM - 1) || undo > SEMAEM) + goto out_of_range; + un->semadj[sop->sem_num] = undo; + } + + curr->semval = result; + } + + sop--; + pid = q->pid; + while (sop >= sops) { + sma->sem_base[sop->sem_num].sempid = pid; + sop--; + } + + return 0; + +out_of_range: + result = -ERANGE; + goto undo; + +would_block: + q->blocking = sop; + + if (sop->sem_flg & IPC_NOWAIT) + result = -EAGAIN; + else + result = 1; + +undo: + sop--; + while (sop >= sops) { + sem_op = sop->sem_op; + sma->sem_base[sop->sem_num].semval -= sem_op; + if (sop->sem_flg & SEM_UNDO) + un->semadj[sop->sem_num] += sem_op; + sop--; + } + + return result; +} + +/** wake_up_sem_queue_prepare(q, error): Prepare wake-up + * @q: queue entry that must be signaled + * @error: Error value for the signal + * + * Prepare the wake-up of the queue entry q. + */ +static void wake_up_sem_queue_prepare(struct list_head *pt, + struct sem_queue *q, int error) +{ +#ifdef CONFIG_PREEMPT_RT_BASE + struct task_struct *p = q->sleeper; + get_task_struct(p); + q->status = error; + wake_up_process(p); + put_task_struct(p); +#else + if (list_empty(pt)) { + /* + * Hold preempt off so that we don't get preempted and have the + * wakee busy-wait until we're scheduled back on. + */ + preempt_disable(); + } + q->status = IN_WAKEUP; + q->pid = error; + + list_add_tail(&q->list, pt); +#endif +} + +/** + * wake_up_sem_queue_do - do the actual wake-up + * @pt: list of tasks to be woken up + * + * Do the actual wake-up. + * The function is called without any locks held, thus the semaphore array + * could be destroyed already and the tasks can disappear as soon as the + * status is set to the actual return code. + */ +static void wake_up_sem_queue_do(struct list_head *pt) +{ +#ifndef CONFIG_PREEMPT_RT_BASE + struct sem_queue *q, *t; + int did_something; + + did_something = !list_empty(pt); + list_for_each_entry_safe(q, t, pt, list) { + wake_up_process(q->sleeper); + /* q can disappear immediately after writing q->status. */ + smp_wmb(); + q->status = q->pid; + } + if (did_something) + preempt_enable(); +#endif +} + +static void unlink_queue(struct sem_array *sma, struct sem_queue *q) +{ + list_del(&q->list); + if (q->nsops > 1) + sma->complex_count--; +} + +/** check_restart(sma, q) + * @sma: semaphore array + * @q: the operation that just completed + * + * update_queue is O(N^2) when it restarts scanning the whole queue of + * waiting operations. Therefore this function checks if the restart is + * really necessary. It is called after a previously waiting operation + * modified the array. + * Note that wait-for-zero operations are handled without restart. + */ +static int check_restart(struct sem_array *sma, struct sem_queue *q) +{ + /* pending complex alter operations are too difficult to analyse */ + if (!list_empty(&sma->pending_alter)) + return 1; + + /* we were a sleeping complex operation. Too difficult */ + if (q->nsops > 1) + return 1; + + /* It is impossible that someone waits for the new value: + * - complex operations always restart. + * - wait-for-zero are handled seperately. + * - q is a previously sleeping simple operation that + * altered the array. It must be a decrement, because + * simple increments never sleep. + * - If there are older (higher priority) decrements + * in the queue, then they have observed the original + * semval value and couldn't proceed. The operation + * decremented to value - thus they won't proceed either. + */ + return 0; +} + +/** + * wake_const_ops - wake up non-alter tasks + * @sma: semaphore array. + * @semnum: semaphore that was modified. + * @pt: list head for the tasks that must be woken up. + * + * wake_const_ops must be called after a semaphore in a semaphore array + * was set to 0. If complex const operations are pending, wake_const_ops must + * be called with semnum = -1, as well as with the number of each modified + * semaphore. + * The tasks that must be woken up are added to @pt. The return code + * is stored in q->pid. + * The function returns 1 if at least one operation was completed successfully. + */ +static int wake_const_ops(struct sem_array *sma, int semnum, + struct list_head *pt) +{ + struct sem_queue *q; + struct list_head *walk; + struct list_head *pending_list; + int semop_completed = 0; + + if (semnum == -1) + pending_list = &sma->pending_const; + else + pending_list = &sma->sem_base[semnum].pending_const; + + walk = pending_list->next; + while (walk != pending_list) { + int error; + + q = container_of(walk, struct sem_queue, list); + walk = walk->next; + + error = perform_atomic_semop(sma, q); + + if (error <= 0) { + /* operation completed, remove from queue & wakeup */ + + unlink_queue(sma, q); + + wake_up_sem_queue_prepare(pt, q, error); + if (error == 0) + semop_completed = 1; + } + } + return semop_completed; +} + +/** + * do_smart_wakeup_zero - wakeup all wait for zero tasks + * @sma: semaphore array + * @sops: operations that were performed + * @nsops: number of operations + * @pt: list head of the tasks that must be woken up. + * + * Checks all required queue for wait-for-zero operations, based + * on the actual changes that were performed on the semaphore array. + * The function returns 1 if at least one operation was completed successfully. + */ +static int do_smart_wakeup_zero(struct sem_array *sma, struct sembuf *sops, + int nsops, struct list_head *pt) +{ + int i; + int semop_completed = 0; + int got_zero = 0; + + /* first: the per-semaphore queues, if known */ + if (sops) { + for (i = 0; i < nsops; i++) { + int num = sops[i].sem_num; + + if (sma->sem_base[num].semval == 0) { + got_zero = 1; + semop_completed |= wake_const_ops(sma, num, pt); + } + } + } else { + /* + * No sops means modified semaphores not known. + * Assume all were changed. + */ + for (i = 0; i < sma->sem_nsems; i++) { + if (sma->sem_base[i].semval == 0) { + got_zero = 1; + semop_completed |= wake_const_ops(sma, i, pt); + } + } + } + /* + * If one of the modified semaphores got 0, + * then check the global queue, too. + */ + if (got_zero) + semop_completed |= wake_const_ops(sma, -1, pt); + + return semop_completed; +} + + +/** + * update_queue - look for tasks that can be completed. + * @sma: semaphore array. + * @semnum: semaphore that was modified. + * @pt: list head for the tasks that must be woken up. + * + * update_queue must be called after a semaphore in a semaphore array + * was modified. If multiple semaphores were modified, update_queue must + * be called with semnum = -1, as well as with the number of each modified + * semaphore. + * The tasks that must be woken up are added to @pt. The return code + * is stored in q->pid. + * The function internally checks if const operations can now succeed. + * + * The function return 1 if at least one semop was completed successfully. + */ +static int update_queue(struct sem_array *sma, int semnum, struct list_head *pt) +{ + struct sem_queue *q; + struct list_head *walk; + struct list_head *pending_list; + int semop_completed = 0; + + if (semnum == -1) + pending_list = &sma->pending_alter; + else + pending_list = &sma->sem_base[semnum].pending_alter; + +again: + walk = pending_list->next; + while (walk != pending_list) { + int error, restart; + + q = container_of(walk, struct sem_queue, list); + walk = walk->next; + + /* If we are scanning the single sop, per-semaphore list of + * one semaphore and that semaphore is 0, then it is not + * necessary to scan further: simple increments + * that affect only one entry succeed immediately and cannot + * be in the per semaphore pending queue, and decrements + * cannot be successful if the value is already 0. + */ + if (semnum != -1 && sma->sem_base[semnum].semval == 0) + break; + + error = perform_atomic_semop(sma, q); + + /* Does q->sleeper still need to sleep? */ + if (error > 0) + continue; + + unlink_queue(sma, q); + + if (error) { + restart = 0; + } else { + semop_completed = 1; + do_smart_wakeup_zero(sma, q->sops, q->nsops, pt); + restart = check_restart(sma, q); + } + + wake_up_sem_queue_prepare(pt, q, error); + if (restart) + goto again; + } + return semop_completed; +} + +/** + * set_semotime - set sem_otime + * @sma: semaphore array + * @sops: operations that modified the array, may be NULL + * + * sem_otime is replicated to avoid cache line trashing. + * This function sets one instance to the current time. + */ +static void set_semotime(struct sem_array *sma, struct sembuf *sops) +{ + if (sops == NULL) { + sma->sem_base[0].sem_otime = get_seconds(); + } else { + sma->sem_base[sops[0].sem_num].sem_otime = + get_seconds(); + } +} + +/** + * do_smart_update - optimized update_queue + * @sma: semaphore array + * @sops: operations that were performed + * @nsops: number of operations + * @otime: force setting otime + * @pt: list head of the tasks that must be woken up. + * + * do_smart_update() does the required calls to update_queue and wakeup_zero, + * based on the actual changes that were performed on the semaphore array. + * Note that the function does not do the actual wake-up: the caller is + * responsible for calling wake_up_sem_queue_do(@pt). + * It is safe to perform this call after dropping all locks. + */ +static void do_smart_update(struct sem_array *sma, struct sembuf *sops, int nsops, + int otime, struct list_head *pt) +{ + int i; + + otime |= do_smart_wakeup_zero(sma, sops, nsops, pt); + + if (!list_empty(&sma->pending_alter)) { + /* semaphore array uses the global queue - just process it. */ + otime |= update_queue(sma, -1, pt); + } else { + if (!sops) { + /* + * No sops, thus the modified semaphores are not + * known. Check all. + */ + for (i = 0; i < sma->sem_nsems; i++) + otime |= update_queue(sma, i, pt); + } else { + /* + * Check the semaphores that were increased: + * - No complex ops, thus all sleeping ops are + * decrease. + * - if we decreased the value, then any sleeping + * semaphore ops wont be able to run: If the + * previous value was too small, then the new + * value will be too small, too. + */ + for (i = 0; i < nsops; i++) { + if (sops[i].sem_op > 0) { + otime |= update_queue(sma, + sops[i].sem_num, pt); + } + } + } + } + if (otime) + set_semotime(sma, sops); +} + +/* + * check_qop: Test if a queued operation sleeps on the semaphore semnum + */ +static int check_qop(struct sem_array *sma, int semnum, struct sem_queue *q, + bool count_zero) +{ + struct sembuf *sop = q->blocking; + + /* + * Linux always (since 0.99.10) reported a task as sleeping on all + * semaphores. This violates SUS, therefore it was changed to the + * standard compliant behavior. + * Give the administrators a chance to notice that an application + * might misbehave because it relies on the Linux behavior. + */ + pr_info_once("semctl(GETNCNT/GETZCNT) is since 3.16 Single Unix Specification compliant.\n" + "The task %s (%d) triggered the difference, watch for misbehavior.\n", + current->comm, task_pid_nr(current)); + + if (sop->sem_num != semnum) + return 0; + + if (count_zero && sop->sem_op == 0) + return 1; + if (!count_zero && sop->sem_op < 0) + return 1; + + return 0; +} + +/* The following counts are associated to each semaphore: + * semncnt number of tasks waiting on semval being nonzero + * semzcnt number of tasks waiting on semval being zero + * + * Per definition, a task waits only on the semaphore of the first semop + * that cannot proceed, even if additional operation would block, too. + */ +static int count_semcnt(struct sem_array *sma, ushort semnum, + bool count_zero) +{ + struct list_head *l; + struct sem_queue *q; + int semcnt; + + semcnt = 0; + /* First: check the simple operations. They are easy to evaluate */ + if (count_zero) + l = &sma->sem_base[semnum].pending_const; + else + l = &sma->sem_base[semnum].pending_alter; + + list_for_each_entry(q, l, list) { + /* all task on a per-semaphore list sleep on exactly + * that semaphore + */ + semcnt++; + } + + /* Then: check the complex operations. */ + list_for_each_entry(q, &sma->pending_alter, list) { + semcnt += check_qop(sma, semnum, q, count_zero); + } + if (count_zero) { + list_for_each_entry(q, &sma->pending_const, list) { + semcnt += check_qop(sma, semnum, q, count_zero); + } + } + return semcnt; +} + +/* Free a semaphore set. freeary() is called with sem_ids.rwsem locked + * as a writer and the spinlock for this semaphore set hold. sem_ids.rwsem + * remains locked on exit. + */ +static void freeary(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp) +{ + struct sem_undo *un, *tu; + struct sem_queue *q, *tq; + struct sem_array *sma = container_of(ipcp, struct sem_array, sem_perm); + struct list_head tasks; + int i; + + /* Free the existing undo structures for this semaphore set. */ + ipc_assert_locked_object(&sma->sem_perm); + list_for_each_entry_safe(un, tu, &sma->list_id, list_id) { + list_del(&un->list_id); + spin_lock(&un->ulp->lock); + un->semid = -1; + list_del_rcu(&un->list_proc); + spin_unlock(&un->ulp->lock); + kfree_rcu(un, rcu); + } + + /* Wake up all pending processes and let them fail with EIDRM. */ + INIT_LIST_HEAD(&tasks); + list_for_each_entry_safe(q, tq, &sma->pending_const, list) { + unlink_queue(sma, q); + wake_up_sem_queue_prepare(&tasks, q, -EIDRM); + } + + list_for_each_entry_safe(q, tq, &sma->pending_alter, list) { + unlink_queue(sma, q); + wake_up_sem_queue_prepare(&tasks, q, -EIDRM); + } + for (i = 0; i < sma->sem_nsems; i++) { + struct sem *sem = sma->sem_base + i; + list_for_each_entry_safe(q, tq, &sem->pending_const, list) { + unlink_queue(sma, q); + wake_up_sem_queue_prepare(&tasks, q, -EIDRM); + } + list_for_each_entry_safe(q, tq, &sem->pending_alter, list) { + unlink_queue(sma, q); + wake_up_sem_queue_prepare(&tasks, q, -EIDRM); + } + } + + /* Remove the semaphore set from the IDR */ + sem_rmid(ns, sma); + sem_unlock(sma, -1); + rcu_read_unlock(); + + wake_up_sem_queue_do(&tasks); + ns->used_sems -= sma->sem_nsems; + ipc_rcu_putref(sma, sem_rcu_free); +} + +static unsigned long copy_semid_to_user(void __user *buf, struct semid64_ds *in, int version) +{ + switch (version) { + case IPC_64: + return copy_to_user(buf, in, sizeof(*in)); + case IPC_OLD: + { + struct semid_ds out; + + memset(&out, 0, sizeof(out)); + + ipc64_perm_to_ipc_perm(&in->sem_perm, &out.sem_perm); + + out.sem_otime = in->sem_otime; + out.sem_ctime = in->sem_ctime; + out.sem_nsems = in->sem_nsems; + + return copy_to_user(buf, &out, sizeof(out)); + } + default: + return -EINVAL; + } +} + +static time_t get_semotime(struct sem_array *sma) +{ + int i; + time_t res; + + res = sma->sem_base[0].sem_otime; + for (i = 1; i < sma->sem_nsems; i++) { + time_t to = sma->sem_base[i].sem_otime; + + if (to > res) + res = to; + } + return res; +} + +static int semctl_nolock(struct ipc_namespace *ns, int semid, + int cmd, int version, void __user *p) +{ + int err; + struct sem_array *sma; + + switch (cmd) { + case IPC_INFO: + case SEM_INFO: + { + struct seminfo seminfo; + int max_id; + + err = security_sem_semctl(NULL, cmd); + if (err) + return err; + + memset(&seminfo, 0, sizeof(seminfo)); + seminfo.semmni = ns->sc_semmni; + seminfo.semmns = ns->sc_semmns; + seminfo.semmsl = ns->sc_semmsl; + seminfo.semopm = ns->sc_semopm; + seminfo.semvmx = SEMVMX; + seminfo.semmnu = SEMMNU; + seminfo.semmap = SEMMAP; + seminfo.semume = SEMUME; + down_read(&sem_ids(ns).rwsem); + if (cmd == SEM_INFO) { + seminfo.semusz = sem_ids(ns).in_use; + seminfo.semaem = ns->used_sems; + } else { + seminfo.semusz = SEMUSZ; + seminfo.semaem = SEMAEM; + } + max_id = ipc_get_maxid(&sem_ids(ns)); + up_read(&sem_ids(ns).rwsem); + if (copy_to_user(p, &seminfo, sizeof(struct seminfo))) + return -EFAULT; + return (max_id < 0) ? 0 : max_id; + } + case IPC_STAT: + case SEM_STAT: + { + struct semid64_ds tbuf; + int id = 0; + + memset(&tbuf, 0, sizeof(tbuf)); + + rcu_read_lock(); + if (cmd == SEM_STAT) { + sma = sem_obtain_object(ns, semid); + if (IS_ERR(sma)) { + err = PTR_ERR(sma); + goto out_unlock; + } + id = sma->sem_perm.id; + } else { + sma = sem_obtain_object_check(ns, semid); + if (IS_ERR(sma)) { + err = PTR_ERR(sma); + goto out_unlock; + } + } + + err = -EACCES; + if (ipcperms(ns, &sma->sem_perm, S_IRUGO)) + goto out_unlock; + + err = security_sem_semctl(sma, cmd); + if (err) + goto out_unlock; + + kernel_to_ipc64_perm(&sma->sem_perm, &tbuf.sem_perm); + tbuf.sem_otime = get_semotime(sma); + tbuf.sem_ctime = sma->sem_ctime; + tbuf.sem_nsems = sma->sem_nsems; + rcu_read_unlock(); + if (copy_semid_to_user(p, &tbuf, version)) + return -EFAULT; + return id; + } + default: + return -EINVAL; + } +out_unlock: + rcu_read_unlock(); + return err; +} + +static int semctl_setval(struct ipc_namespace *ns, int semid, int semnum, + unsigned long arg) +{ + struct sem_undo *un; + struct sem_array *sma; + struct sem *curr; + int err; + struct list_head tasks; + int val; +#if defined(CONFIG_64BIT) && defined(__BIG_ENDIAN) + /* big-endian 64bit */ + val = arg >> 32; +#else + /* 32bit or little-endian 64bit */ + val = arg; +#endif + + if (val > SEMVMX || val < 0) + return -ERANGE; + + INIT_LIST_HEAD(&tasks); + + rcu_read_lock(); + sma = sem_obtain_object_check(ns, semid); + if (IS_ERR(sma)) { + rcu_read_unlock(); + return PTR_ERR(sma); + } + + if (semnum < 0 || semnum >= sma->sem_nsems) { + rcu_read_unlock(); + return -EINVAL; + } + + + if (ipcperms(ns, &sma->sem_perm, S_IWUGO)) { + rcu_read_unlock(); + return -EACCES; + } + + err = security_sem_semctl(sma, SETVAL); + if (err) { + rcu_read_unlock(); + return -EACCES; + } + + sem_lock(sma, NULL, -1); + + if (!ipc_valid_object(&sma->sem_perm)) { + sem_unlock(sma, -1); + rcu_read_unlock(); + return -EIDRM; + } + + curr = &sma->sem_base[semnum]; + + ipc_assert_locked_object(&sma->sem_perm); + list_for_each_entry(un, &sma->list_id, list_id) + un->semadj[semnum] = 0; + + curr->semval = val; + curr->sempid = task_tgid_vnr(current); + sma->sem_ctime = get_seconds(); + /* maybe some queued-up processes were waiting for this */ + do_smart_update(sma, NULL, 0, 0, &tasks); + sem_unlock(sma, -1); + rcu_read_unlock(); + wake_up_sem_queue_do(&tasks); + return 0; +} + +static int semctl_main(struct ipc_namespace *ns, int semid, int semnum, + int cmd, void __user *p) +{ + struct sem_array *sma; + struct sem *curr; + int err, nsems; + ushort fast_sem_io[SEMMSL_FAST]; + ushort *sem_io = fast_sem_io; + struct list_head tasks; + + INIT_LIST_HEAD(&tasks); + + rcu_read_lock(); + sma = sem_obtain_object_check(ns, semid); + if (IS_ERR(sma)) { + rcu_read_unlock(); + return PTR_ERR(sma); + } + + nsems = sma->sem_nsems; + + err = -EACCES; + if (ipcperms(ns, &sma->sem_perm, cmd == SETALL ? S_IWUGO : S_IRUGO)) + goto out_rcu_wakeup; + + err = security_sem_semctl(sma, cmd); + if (err) + goto out_rcu_wakeup; + + err = -EACCES; + switch (cmd) { + case GETALL: + { + ushort __user *array = p; + int i; + + sem_lock(sma, NULL, -1); + if (!ipc_valid_object(&sma->sem_perm)) { + err = -EIDRM; + goto out_unlock; + } + if (nsems > SEMMSL_FAST) { + if (!ipc_rcu_getref(sma)) { + err = -EIDRM; + goto out_unlock; + } + sem_unlock(sma, -1); + rcu_read_unlock(); + sem_io = ipc_alloc(sizeof(ushort)*nsems); + if (sem_io == NULL) { + ipc_rcu_putref(sma, ipc_rcu_free); + return -ENOMEM; + } + + rcu_read_lock(); + sem_lock_and_putref(sma); + if (!ipc_valid_object(&sma->sem_perm)) { + err = -EIDRM; + goto out_unlock; + } + } + for (i = 0; i < sma->sem_nsems; i++) + sem_io[i] = sma->sem_base[i].semval; + sem_unlock(sma, -1); + rcu_read_unlock(); + err = 0; + if (copy_to_user(array, sem_io, nsems*sizeof(ushort))) + err = -EFAULT; + goto out_free; + } + case SETALL: + { + int i; + struct sem_undo *un; + + if (!ipc_rcu_getref(sma)) { + err = -EIDRM; + goto out_rcu_wakeup; + } + rcu_read_unlock(); + + if (nsems > SEMMSL_FAST) { + sem_io = ipc_alloc(sizeof(ushort)*nsems); + if (sem_io == NULL) { + ipc_rcu_putref(sma, ipc_rcu_free); + return -ENOMEM; + } + } + + if (copy_from_user(sem_io, p, nsems*sizeof(ushort))) { + ipc_rcu_putref(sma, ipc_rcu_free); + err = -EFAULT; + goto out_free; + } + + for (i = 0; i < nsems; i++) { + if (sem_io[i] > SEMVMX) { + ipc_rcu_putref(sma, ipc_rcu_free); + err = -ERANGE; + goto out_free; + } + } + rcu_read_lock(); + sem_lock_and_putref(sma); + if (!ipc_valid_object(&sma->sem_perm)) { + err = -EIDRM; + goto out_unlock; + } + + for (i = 0; i < nsems; i++) + sma->sem_base[i].semval = sem_io[i]; + + ipc_assert_locked_object(&sma->sem_perm); + list_for_each_entry(un, &sma->list_id, list_id) { + for (i = 0; i < nsems; i++) + un->semadj[i] = 0; + } + sma->sem_ctime = get_seconds(); + /* maybe some queued-up processes were waiting for this */ + do_smart_update(sma, NULL, 0, 0, &tasks); + err = 0; + goto out_unlock; + } + /* GETVAL, GETPID, GETNCTN, GETZCNT: fall-through */ + } + err = -EINVAL; + if (semnum < 0 || semnum >= nsems) + goto out_rcu_wakeup; + + sem_lock(sma, NULL, -1); + if (!ipc_valid_object(&sma->sem_perm)) { + err = -EIDRM; + goto out_unlock; + } + curr = &sma->sem_base[semnum]; + + switch (cmd) { + case GETVAL: + err = curr->semval; + goto out_unlock; + case GETPID: + err = curr->sempid; + goto out_unlock; + case GETNCNT: + err = count_semcnt(sma, semnum, 0); + goto out_unlock; + case GETZCNT: + err = count_semcnt(sma, semnum, 1); + goto out_unlock; + } + +out_unlock: + sem_unlock(sma, -1); +out_rcu_wakeup: + rcu_read_unlock(); + wake_up_sem_queue_do(&tasks); +out_free: + if (sem_io != fast_sem_io) + ipc_free(sem_io, sizeof(ushort)*nsems); + return err; +} + +static inline unsigned long +copy_semid_from_user(struct semid64_ds *out, void __user *buf, int version) +{ + switch (version) { + case IPC_64: + if (copy_from_user(out, buf, sizeof(*out))) + return -EFAULT; + return 0; + case IPC_OLD: + { + struct semid_ds tbuf_old; + + if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old))) + return -EFAULT; + + out->sem_perm.uid = tbuf_old.sem_perm.uid; + out->sem_perm.gid = tbuf_old.sem_perm.gid; + out->sem_perm.mode = tbuf_old.sem_perm.mode; + + return 0; + } + default: + return -EINVAL; + } +} + +/* + * This function handles some semctl commands which require the rwsem + * to be held in write mode. + * NOTE: no locks must be held, the rwsem is taken inside this function. + */ +static int semctl_down(struct ipc_namespace *ns, int semid, + int cmd, int version, void __user *p) +{ + struct sem_array *sma; + int err; + struct semid64_ds semid64; + struct kern_ipc_perm *ipcp; + + if (cmd == IPC_SET) { + if (copy_semid_from_user(&semid64, p, version)) + return -EFAULT; + } + + down_write(&sem_ids(ns).rwsem); + rcu_read_lock(); + + ipcp = ipcctl_pre_down_nolock(ns, &sem_ids(ns), semid, cmd, + &semid64.sem_perm, 0); + if (IS_ERR(ipcp)) { + err = PTR_ERR(ipcp); + goto out_unlock1; + } + + sma = container_of(ipcp, struct sem_array, sem_perm); + + err = security_sem_semctl(sma, cmd); + if (err) + goto out_unlock1; + + switch (cmd) { + case IPC_RMID: + sem_lock(sma, NULL, -1); + /* freeary unlocks the ipc object and rcu */ + freeary(ns, ipcp); + goto out_up; + case IPC_SET: + sem_lock(sma, NULL, -1); + err = ipc_update_perm(&semid64.sem_perm, ipcp); + if (err) + goto out_unlock0; + sma->sem_ctime = get_seconds(); + break; + default: + err = -EINVAL; + goto out_unlock1; + } + +out_unlock0: + sem_unlock(sma, -1); +out_unlock1: + rcu_read_unlock(); +out_up: + up_write(&sem_ids(ns).rwsem); + return err; +} + +SYSCALL_DEFINE4(semctl, int, semid, int, semnum, int, cmd, unsigned long, arg) +{ + int version; + struct ipc_namespace *ns; + void __user *p = (void __user *)arg; + + if (semid < 0) + return -EINVAL; + + version = ipc_parse_version(&cmd); + ns = current->nsproxy->ipc_ns; + + switch (cmd) { + case IPC_INFO: + case SEM_INFO: + case IPC_STAT: + case SEM_STAT: + return semctl_nolock(ns, semid, cmd, version, p); + case GETALL: + case GETVAL: + case GETPID: + case GETNCNT: + case GETZCNT: + case SETALL: + return semctl_main(ns, semid, semnum, cmd, p); + case SETVAL: + return semctl_setval(ns, semid, semnum, arg); + case IPC_RMID: + case IPC_SET: + return semctl_down(ns, semid, cmd, version, p); + default: + return -EINVAL; + } +} + +/* If the task doesn't already have a undo_list, then allocate one + * here. We guarantee there is only one thread using this undo list, + * and current is THE ONE + * + * If this allocation and assignment succeeds, but later + * portions of this code fail, there is no need to free the sem_undo_list. + * Just let it stay associated with the task, and it'll be freed later + * at exit time. + * + * This can block, so callers must hold no locks. + */ +static inline int get_undo_list(struct sem_undo_list **undo_listp) +{ + struct sem_undo_list *undo_list; + + undo_list = current->sysvsem.undo_list; + if (!undo_list) { + undo_list = kzalloc(sizeof(*undo_list), GFP_KERNEL); + if (undo_list == NULL) + return -ENOMEM; + spin_lock_init(&undo_list->lock); + atomic_set(&undo_list->refcnt, 1); + INIT_LIST_HEAD(&undo_list->list_proc); + + current->sysvsem.undo_list = undo_list; + } + *undo_listp = undo_list; + return 0; +} + +static struct sem_undo *__lookup_undo(struct sem_undo_list *ulp, int semid) +{ + struct sem_undo *un; + + list_for_each_entry_rcu(un, &ulp->list_proc, list_proc) { + if (un->semid == semid) + return un; + } + return NULL; +} + +static struct sem_undo *lookup_undo(struct sem_undo_list *ulp, int semid) +{ + struct sem_undo *un; + + assert_spin_locked(&ulp->lock); + + un = __lookup_undo(ulp, semid); + if (un) { + list_del_rcu(&un->list_proc); + list_add_rcu(&un->list_proc, &ulp->list_proc); + } + return un; +} + +/** + * find_alloc_undo - lookup (and if not present create) undo array + * @ns: namespace + * @semid: semaphore array id + * + * The function looks up (and if not present creates) the undo structure. + * The size of the undo structure depends on the size of the semaphore + * array, thus the alloc path is not that straightforward. + * Lifetime-rules: sem_undo is rcu-protected, on success, the function + * performs a rcu_read_lock(). + */ +static struct sem_undo *find_alloc_undo(struct ipc_namespace *ns, int semid) +{ + struct sem_array *sma; + struct sem_undo_list *ulp; + struct sem_undo *un, *new; + int nsems, error; + + error = get_undo_list(&ulp); + if (error) + return ERR_PTR(error); + + rcu_read_lock(); + spin_lock(&ulp->lock); + un = lookup_undo(ulp, semid); + spin_unlock(&ulp->lock); + if (likely(un != NULL)) + goto out; + + /* no undo structure around - allocate one. */ + /* step 1: figure out the size of the semaphore array */ + sma = sem_obtain_object_check(ns, semid); + if (IS_ERR(sma)) { + rcu_read_unlock(); + return ERR_CAST(sma); + } + + nsems = sma->sem_nsems; + if (!ipc_rcu_getref(sma)) { + rcu_read_unlock(); + un = ERR_PTR(-EIDRM); + goto out; + } + rcu_read_unlock(); + + /* step 2: allocate new undo structure */ + new = kzalloc(sizeof(struct sem_undo) + sizeof(short)*nsems, GFP_KERNEL); + if (!new) { + ipc_rcu_putref(sma, ipc_rcu_free); + return ERR_PTR(-ENOMEM); + } + + /* step 3: Acquire the lock on semaphore array */ + rcu_read_lock(); + sem_lock_and_putref(sma); + if (!ipc_valid_object(&sma->sem_perm)) { + sem_unlock(sma, -1); + rcu_read_unlock(); + kfree(new); + un = ERR_PTR(-EIDRM); + goto out; + } + spin_lock(&ulp->lock); + + /* + * step 4: check for races: did someone else allocate the undo struct? + */ + un = lookup_undo(ulp, semid); + if (un) { + kfree(new); + goto success; + } + /* step 5: initialize & link new undo structure */ + new->semadj = (short *) &new[1]; + new->ulp = ulp; + new->semid = semid; + assert_spin_locked(&ulp->lock); + list_add_rcu(&new->list_proc, &ulp->list_proc); + ipc_assert_locked_object(&sma->sem_perm); + list_add(&new->list_id, &sma->list_id); + un = new; + +success: + spin_unlock(&ulp->lock); + sem_unlock(sma, -1); +out: + return un; +} + + +/** + * get_queue_result - retrieve the result code from sem_queue + * @q: Pointer to queue structure + * + * Retrieve the return code from the pending queue. If IN_WAKEUP is found in + * q->status, then we must loop until the value is replaced with the final + * value: This may happen if a task is woken up by an unrelated event (e.g. + * signal) and in parallel the task is woken up by another task because it got + * the requested semaphores. + * + * The function can be called with or without holding the semaphore spinlock. + */ +static int get_queue_result(struct sem_queue *q) +{ + int error; + + error = q->status; + while (unlikely(error == IN_WAKEUP)) { + cpu_relax(); + error = q->status; + } + + return error; +} + +SYSCALL_DEFINE4(semtimedop, int, semid, struct sembuf __user *, tsops, + unsigned, nsops, const struct timespec __user *, timeout) +{ + int error = -EINVAL; + struct sem_array *sma; + struct sembuf fast_sops[SEMOPM_FAST]; + struct sembuf *sops = fast_sops, *sop; + struct sem_undo *un; + int undos = 0, alter = 0, max, locknum; + struct sem_queue queue; + unsigned long jiffies_left = 0; + struct ipc_namespace *ns; + struct list_head tasks; + + ns = current->nsproxy->ipc_ns; + + if (nsops < 1 || semid < 0) + return -EINVAL; + if (nsops > ns->sc_semopm) + return -E2BIG; + if (nsops > SEMOPM_FAST) { + sops = kmalloc(sizeof(*sops)*nsops, GFP_KERNEL); + if (sops == NULL) + return -ENOMEM; + } + if (copy_from_user(sops, tsops, nsops * sizeof(*tsops))) { + error = -EFAULT; + goto out_free; + } + if (timeout) { + struct timespec _timeout; + if (copy_from_user(&_timeout, timeout, sizeof(*timeout))) { + error = -EFAULT; + goto out_free; + } + if (_timeout.tv_sec < 0 || _timeout.tv_nsec < 0 || + _timeout.tv_nsec >= 1000000000L) { + error = -EINVAL; + goto out_free; + } + jiffies_left = timespec_to_jiffies(&_timeout); + } + max = 0; + for (sop = sops; sop < sops + nsops; sop++) { + if (sop->sem_num >= max) + max = sop->sem_num; + if (sop->sem_flg & SEM_UNDO) + undos = 1; + if (sop->sem_op != 0) + alter = 1; + } + + INIT_LIST_HEAD(&tasks); + + if (undos) { + /* On success, find_alloc_undo takes the rcu_read_lock */ + un = find_alloc_undo(ns, semid); + if (IS_ERR(un)) { + error = PTR_ERR(un); + goto out_free; + } + } else { + un = NULL; + rcu_read_lock(); + } + + sma = sem_obtain_object_check(ns, semid); + if (IS_ERR(sma)) { + rcu_read_unlock(); + error = PTR_ERR(sma); + goto out_free; + } + + error = -EFBIG; + if (max >= sma->sem_nsems) + goto out_rcu_wakeup; + + error = -EACCES; + if (ipcperms(ns, &sma->sem_perm, alter ? S_IWUGO : S_IRUGO)) + goto out_rcu_wakeup; + + error = security_sem_semop(sma, sops, nsops, alter); + if (error) + goto out_rcu_wakeup; + + error = -EIDRM; + locknum = sem_lock(sma, sops, nsops); + /* + * We eventually might perform the following check in a lockless + * fashion, considering ipc_valid_object() locking constraints. + * If nsops == 1 and there is no contention for sem_perm.lock, then + * only a per-semaphore lock is held and it's OK to proceed with the + * check below. More details on the fine grained locking scheme + * entangled here and why it's RMID race safe on comments at sem_lock() + */ + if (!ipc_valid_object(&sma->sem_perm)) + goto out_unlock_free; + /* + * semid identifiers are not unique - find_alloc_undo may have + * allocated an undo structure, it was invalidated by an RMID + * and now a new array with received the same id. Check and fail. + * This case can be detected checking un->semid. The existence of + * "un" itself is guaranteed by rcu. + */ + if (un && un->semid == -1) + goto out_unlock_free; + + queue.sops = sops; + queue.nsops = nsops; + queue.undo = un; + queue.pid = task_tgid_vnr(current); + queue.alter = alter; + + error = perform_atomic_semop(sma, &queue); + if (error == 0) { + /* If the operation was successful, then do + * the required updates. + */ + if (alter) + do_smart_update(sma, sops, nsops, 1, &tasks); + else + set_semotime(sma, sops); + } + if (error <= 0) + goto out_unlock_free; + + /* We need to sleep on this operation, so we put the current + * task into the pending queue and go to sleep. + */ + + if (nsops == 1) { + struct sem *curr; + curr = &sma->sem_base[sops->sem_num]; + + if (alter) { + if (sma->complex_count) { + list_add_tail(&queue.list, + &sma->pending_alter); + } else { + + list_add_tail(&queue.list, + &curr->pending_alter); + } + } else { + list_add_tail(&queue.list, &curr->pending_const); + } + } else { + if (!sma->complex_count) + merge_queues(sma); + + if (alter) + list_add_tail(&queue.list, &sma->pending_alter); + else + list_add_tail(&queue.list, &sma->pending_const); + + sma->complex_count++; + } + + queue.status = -EINTR; + queue.sleeper = current; + +sleep_again: + __set_current_state(TASK_INTERRUPTIBLE); + sem_unlock(sma, locknum); + rcu_read_unlock(); + + if (timeout) + jiffies_left = schedule_timeout(jiffies_left); + else + schedule(); + + error = get_queue_result(&queue); + + if (error != -EINTR) { + /* fast path: update_queue already obtained all requested + * resources. + * Perform a smp_mb(): User space could assume that semop() + * is a memory barrier: Without the mb(), the cpu could + * speculatively read in user space stale data that was + * overwritten by the previous owner of the semaphore. + */ + smp_mb(); + + goto out_free; + } + + rcu_read_lock(); + sma = sem_obtain_lock(ns, semid, sops, nsops, &locknum); + + /* + * Wait until it's guaranteed that no wakeup_sem_queue_do() is ongoing. + */ + error = get_queue_result(&queue); + + /* + * Array removed? If yes, leave without sem_unlock(). + */ + if (IS_ERR(sma)) { + rcu_read_unlock(); + goto out_free; + } + + + /* + * If queue.status != -EINTR we are woken up by another process. + * Leave without unlink_queue(), but with sem_unlock(). + */ + if (error != -EINTR) + goto out_unlock_free; + + /* + * If an interrupt occurred we have to clean up the queue + */ + if (timeout && jiffies_left == 0) + error = -EAGAIN; + + /* + * If the wakeup was spurious, just retry + */ + if (error == -EINTR && !signal_pending(current)) + goto sleep_again; + + unlink_queue(sma, &queue); + +out_unlock_free: + sem_unlock(sma, locknum); +out_rcu_wakeup: + rcu_read_unlock(); + wake_up_sem_queue_do(&tasks); +out_free: + if (sops != fast_sops) + kfree(sops); + return error; +} + +SYSCALL_DEFINE3(semop, int, semid, struct sembuf __user *, tsops, + unsigned, nsops) +{ + return sys_semtimedop(semid, tsops, nsops, NULL); +} + +/* If CLONE_SYSVSEM is set, establish sharing of SEM_UNDO state between + * parent and child tasks. + */ + +int copy_semundo(unsigned long clone_flags, struct task_struct *tsk) +{ + struct sem_undo_list *undo_list; + int error; + + if (clone_flags & CLONE_SYSVSEM) { + error = get_undo_list(&undo_list); + if (error) + return error; + atomic_inc(&undo_list->refcnt); + tsk->sysvsem.undo_list = undo_list; + } else + tsk->sysvsem.undo_list = NULL; + + return 0; +} + +/* + * add semadj values to semaphores, free undo structures. + * undo structures are not freed when semaphore arrays are destroyed + * so some of them may be out of date. + * IMPLEMENTATION NOTE: There is some confusion over whether the + * set of adjustments that needs to be done should be done in an atomic + * manner or not. That is, if we are attempting to decrement the semval + * should we queue up and wait until we can do so legally? + * The original implementation attempted to do this (queue and wait). + * The current implementation does not do so. The POSIX standard + * and SVID should be consulted to determine what behavior is mandated. + */ +void exit_sem(struct task_struct *tsk) +{ + struct sem_undo_list *ulp; + + ulp = tsk->sysvsem.undo_list; + if (!ulp) + return; + tsk->sysvsem.undo_list = NULL; + + if (!atomic_dec_and_test(&ulp->refcnt)) + return; + + for (;;) { + struct sem_array *sma; + struct sem_undo *un; + struct list_head tasks; + int semid, i; + + rcu_read_lock(); + un = list_entry_rcu(ulp->list_proc.next, + struct sem_undo, list_proc); + if (&un->list_proc == &ulp->list_proc) + semid = -1; + else + semid = un->semid; + + if (semid == -1) { + rcu_read_unlock(); + break; + } + + sma = sem_obtain_object_check(tsk->nsproxy->ipc_ns, un->semid); + /* exit_sem raced with IPC_RMID, nothing to do */ + if (IS_ERR(sma)) { + rcu_read_unlock(); + continue; + } + + sem_lock(sma, NULL, -1); + /* exit_sem raced with IPC_RMID, nothing to do */ + if (!ipc_valid_object(&sma->sem_perm)) { + sem_unlock(sma, -1); + rcu_read_unlock(); + continue; + } + un = __lookup_undo(ulp, semid); + if (un == NULL) { + /* exit_sem raced with IPC_RMID+semget() that created + * exactly the same semid. Nothing to do. + */ + sem_unlock(sma, -1); + rcu_read_unlock(); + continue; + } + + /* remove un from the linked lists */ + ipc_assert_locked_object(&sma->sem_perm); + list_del(&un->list_id); + + spin_lock(&ulp->lock); + list_del_rcu(&un->list_proc); + spin_unlock(&ulp->lock); + + /* perform adjustments registered in un */ + for (i = 0; i < sma->sem_nsems; i++) { + struct sem *semaphore = &sma->sem_base[i]; + if (un->semadj[i]) { + semaphore->semval += un->semadj[i]; + /* + * Range checks of the new semaphore value, + * not defined by sus: + * - Some unices ignore the undo entirely + * (e.g. HP UX 11i 11.22, Tru64 V5.1) + * - some cap the value (e.g. FreeBSD caps + * at 0, but doesn't enforce SEMVMX) + * + * Linux caps the semaphore value, both at 0 + * and at SEMVMX. + * + * Manfred + */ + if (semaphore->semval < 0) + semaphore->semval = 0; + if (semaphore->semval > SEMVMX) + semaphore->semval = SEMVMX; + semaphore->sempid = task_tgid_vnr(current); + } + } + /* maybe some queued-up processes were waiting for this */ + INIT_LIST_HEAD(&tasks); + do_smart_update(sma, NULL, 0, 1, &tasks); + sem_unlock(sma, -1); + rcu_read_unlock(); + wake_up_sem_queue_do(&tasks); + + kfree_rcu(un, rcu); + } + kfree(ulp); +} + +#ifdef CONFIG_PROC_FS +static int sysvipc_sem_proc_show(struct seq_file *s, void *it) +{ + struct user_namespace *user_ns = seq_user_ns(s); + struct sem_array *sma = it; + time_t sem_otime; + + /* + * The proc interface isn't aware of sem_lock(), it calls + * ipc_lock_object() directly (in sysvipc_find_ipc). + * In order to stay compatible with sem_lock(), we must wait until + * all simple semop() calls have left their critical regions. + */ + sem_wait_array(sma); + + sem_otime = get_semotime(sma); + + seq_printf(s, + "%10d %10d %4o %10u %5u %5u %5u %5u %10lu %10lu\n", + sma->sem_perm.key, + sma->sem_perm.id, + sma->sem_perm.mode, + sma->sem_nsems, + from_kuid_munged(user_ns, sma->sem_perm.uid), + from_kgid_munged(user_ns, sma->sem_perm.gid), + from_kuid_munged(user_ns, sma->sem_perm.cuid), + from_kgid_munged(user_ns, sma->sem_perm.cgid), + sem_otime, + sma->sem_ctime); + + return 0; +} +#endif diff --git a/kernel/ipc/shm.c b/kernel/ipc/shm.c new file mode 100644 index 000000000..6d767071c --- /dev/null +++ b/kernel/ipc/shm.c @@ -0,0 +1,1368 @@ +/* + * linux/ipc/shm.c + * Copyright (C) 1992, 1993 Krishna Balasubramanian + * Many improvements/fixes by Bruno Haible. + * Replaced `struct shm_desc' by `struct vm_area_struct', July 1994. + * Fixed the shm swap deallocation (shm_unuse()), August 1998 Andrea Arcangeli. + * + * /proc/sysvipc/shm support (c) 1999 Dragos Acostachioaie + * BIGMEM support, Andrea Arcangeli + * SMP thread shm, Jean-Luc Boyard + * HIGHMEM support, Ingo Molnar + * Make shmmax, shmall, shmmni sysctl'able, Christoph Rohland + * Shared /dev/zero support, Kanoj Sarcar + * Move the mm functionality over to mm/shmem.c, Christoph Rohland + * + * support for audit of ipc object properties and permission changes + * Dustin Kirkland + * + * namespaces support + * OpenVZ, SWsoft Inc. + * Pavel Emelianov + * + * Better ipc lock (kern_ipc_perm.lock) handling + * Davidlohr Bueso , June 2013. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +#include "util.h" + +struct shm_file_data { + int id; + struct ipc_namespace *ns; + struct file *file; + const struct vm_operations_struct *vm_ops; +}; + +#define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data)) + +static const struct file_operations shm_file_operations; +static const struct vm_operations_struct shm_vm_ops; + +#define shm_ids(ns) ((ns)->ids[IPC_SHM_IDS]) + +#define shm_unlock(shp) \ + ipc_unlock(&(shp)->shm_perm) + +static int newseg(struct ipc_namespace *, struct ipc_params *); +static void shm_open(struct vm_area_struct *vma); +static void shm_close(struct vm_area_struct *vma); +static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp); +#ifdef CONFIG_PROC_FS +static int sysvipc_shm_proc_show(struct seq_file *s, void *it); +#endif + +void shm_init_ns(struct ipc_namespace *ns) +{ + ns->shm_ctlmax = SHMMAX; + ns->shm_ctlall = SHMALL; + ns->shm_ctlmni = SHMMNI; + ns->shm_rmid_forced = 0; + ns->shm_tot = 0; + ipc_init_ids(&shm_ids(ns)); +} + +/* + * Called with shm_ids.rwsem (writer) and the shp structure locked. + * Only shm_ids.rwsem remains locked on exit. + */ +static void do_shm_rmid(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp) +{ + struct shmid_kernel *shp; + shp = container_of(ipcp, struct shmid_kernel, shm_perm); + + if (shp->shm_nattch) { + shp->shm_perm.mode |= SHM_DEST; + /* Do not find it any more */ + shp->shm_perm.key = IPC_PRIVATE; + shm_unlock(shp); + } else + shm_destroy(ns, shp); +} + +#ifdef CONFIG_IPC_NS +void shm_exit_ns(struct ipc_namespace *ns) +{ + free_ipcs(ns, &shm_ids(ns), do_shm_rmid); + idr_destroy(&ns->ids[IPC_SHM_IDS].ipcs_idr); +} +#endif + +static int __init ipc_ns_init(void) +{ + shm_init_ns(&init_ipc_ns); + return 0; +} + +pure_initcall(ipc_ns_init); + +void __init shm_init(void) +{ + ipc_init_proc_interface("sysvipc/shm", +#if BITS_PER_LONG <= 32 + " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n", +#else + " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n", +#endif + IPC_SHM_IDS, sysvipc_shm_proc_show); +} + +static inline struct shmid_kernel *shm_obtain_object(struct ipc_namespace *ns, int id) +{ + struct kern_ipc_perm *ipcp = ipc_obtain_object(&shm_ids(ns), id); + + if (IS_ERR(ipcp)) + return ERR_CAST(ipcp); + + return container_of(ipcp, struct shmid_kernel, shm_perm); +} + +static inline struct shmid_kernel *shm_obtain_object_check(struct ipc_namespace *ns, int id) +{ + struct kern_ipc_perm *ipcp = ipc_obtain_object_check(&shm_ids(ns), id); + + if (IS_ERR(ipcp)) + return ERR_CAST(ipcp); + + return container_of(ipcp, struct shmid_kernel, shm_perm); +} + +/* + * shm_lock_(check_) routines are called in the paths where the rwsem + * is not necessarily held. + */ +static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id) +{ + struct kern_ipc_perm *ipcp = ipc_lock(&shm_ids(ns), id); + + if (IS_ERR(ipcp)) + return (struct shmid_kernel *)ipcp; + + return container_of(ipcp, struct shmid_kernel, shm_perm); +} + +static inline void shm_lock_by_ptr(struct shmid_kernel *ipcp) +{ + rcu_read_lock(); + ipc_lock_object(&ipcp->shm_perm); +} + +static void shm_rcu_free(struct rcu_head *head) +{ + struct ipc_rcu *p = container_of(head, struct ipc_rcu, rcu); + struct shmid_kernel *shp = ipc_rcu_to_struct(p); + + security_shm_free(shp); + ipc_rcu_free(head); +} + +static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s) +{ + list_del(&s->shm_clist); + ipc_rmid(&shm_ids(ns), &s->shm_perm); +} + + +/* This is called by fork, once for every shm attach. */ +static void shm_open(struct vm_area_struct *vma) +{ + struct file *file = vma->vm_file; + struct shm_file_data *sfd = shm_file_data(file); + struct shmid_kernel *shp; + + shp = shm_lock(sfd->ns, sfd->id); + BUG_ON(IS_ERR(shp)); + shp->shm_atim = get_seconds(); + shp->shm_lprid = task_tgid_vnr(current); + shp->shm_nattch++; + shm_unlock(shp); +} + +/* + * shm_destroy - free the struct shmid_kernel + * + * @ns: namespace + * @shp: struct to free + * + * It has to be called with shp and shm_ids.rwsem (writer) locked, + * but returns with shp unlocked and freed. + */ +static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp) +{ + struct file *shm_file; + + shm_file = shp->shm_file; + shp->shm_file = NULL; + ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT; + shm_rmid(ns, shp); + shm_unlock(shp); + if (!is_file_hugepages(shm_file)) + shmem_lock(shm_file, 0, shp->mlock_user); + else if (shp->mlock_user) + user_shm_unlock(i_size_read(file_inode(shm_file)), + shp->mlock_user); + fput(shm_file); + ipc_rcu_putref(shp, shm_rcu_free); +} + +/* + * shm_may_destroy - identifies whether shm segment should be destroyed now + * + * Returns true if and only if there are no active users of the segment and + * one of the following is true: + * + * 1) shmctl(id, IPC_RMID, NULL) was called for this shp + * + * 2) sysctl kernel.shm_rmid_forced is set to 1. + */ +static bool shm_may_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp) +{ + return (shp->shm_nattch == 0) && + (ns->shm_rmid_forced || + (shp->shm_perm.mode & SHM_DEST)); +} + +/* + * remove the attach descriptor vma. + * free memory for segment if it is marked destroyed. + * The descriptor has already been removed from the current->mm->mmap list + * and will later be kfree()d. + */ +static void shm_close(struct vm_area_struct *vma) +{ + struct file *file = vma->vm_file; + struct shm_file_data *sfd = shm_file_data(file); + struct shmid_kernel *shp; + struct ipc_namespace *ns = sfd->ns; + + down_write(&shm_ids(ns).rwsem); + /* remove from the list of attaches of the shm segment */ + shp = shm_lock(ns, sfd->id); + BUG_ON(IS_ERR(shp)); + shp->shm_lprid = task_tgid_vnr(current); + shp->shm_dtim = get_seconds(); + shp->shm_nattch--; + if (shm_may_destroy(ns, shp)) + shm_destroy(ns, shp); + else + shm_unlock(shp); + up_write(&shm_ids(ns).rwsem); +} + +/* Called with ns->shm_ids(ns).rwsem locked */ +static int shm_try_destroy_orphaned(int id, void *p, void *data) +{ + struct ipc_namespace *ns = data; + struct kern_ipc_perm *ipcp = p; + struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm); + + /* + * We want to destroy segments without users and with already + * exit'ed originating process. + * + * As shp->* are changed under rwsem, it's safe to skip shp locking. + */ + if (shp->shm_creator != NULL) + return 0; + + if (shm_may_destroy(ns, shp)) { + shm_lock_by_ptr(shp); + shm_destroy(ns, shp); + } + return 0; +} + +void shm_destroy_orphaned(struct ipc_namespace *ns) +{ + down_write(&shm_ids(ns).rwsem); + if (shm_ids(ns).in_use) + idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_orphaned, ns); + up_write(&shm_ids(ns).rwsem); +} + +/* Locking assumes this will only be called with task == current */ +void exit_shm(struct task_struct *task) +{ + struct ipc_namespace *ns = task->nsproxy->ipc_ns; + struct shmid_kernel *shp, *n; + + if (list_empty(&task->sysvshm.shm_clist)) + return; + + /* + * If kernel.shm_rmid_forced is not set then only keep track of + * which shmids are orphaned, so that a later set of the sysctl + * can clean them up. + */ + if (!ns->shm_rmid_forced) { + down_read(&shm_ids(ns).rwsem); + list_for_each_entry(shp, &task->sysvshm.shm_clist, shm_clist) + shp->shm_creator = NULL; + /* + * Only under read lock but we are only called on current + * so no entry on the list will be shared. + */ + list_del(&task->sysvshm.shm_clist); + up_read(&shm_ids(ns).rwsem); + return; + } + + /* + * Destroy all already created segments, that were not yet mapped, + * and mark any mapped as orphan to cover the sysctl toggling. + * Destroy is skipped if shm_may_destroy() returns false. + */ + down_write(&shm_ids(ns).rwsem); + list_for_each_entry_safe(shp, n, &task->sysvshm.shm_clist, shm_clist) { + shp->shm_creator = NULL; + + if (shm_may_destroy(ns, shp)) { + shm_lock_by_ptr(shp); + shm_destroy(ns, shp); + } + } + + /* Remove the list head from any segments still attached. */ + list_del(&task->sysvshm.shm_clist); + up_write(&shm_ids(ns).rwsem); +} + +static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf) +{ + struct file *file = vma->vm_file; + struct shm_file_data *sfd = shm_file_data(file); + + return sfd->vm_ops->fault(vma, vmf); +} + +#ifdef CONFIG_NUMA +static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new) +{ + struct file *file = vma->vm_file; + struct shm_file_data *sfd = shm_file_data(file); + int err = 0; + if (sfd->vm_ops->set_policy) + err = sfd->vm_ops->set_policy(vma, new); + return err; +} + +static struct mempolicy *shm_get_policy(struct vm_area_struct *vma, + unsigned long addr) +{ + struct file *file = vma->vm_file; + struct shm_file_data *sfd = shm_file_data(file); + struct mempolicy *pol = NULL; + + if (sfd->vm_ops->get_policy) + pol = sfd->vm_ops->get_policy(vma, addr); + else if (vma->vm_policy) + pol = vma->vm_policy; + + return pol; +} +#endif + +static int shm_mmap(struct file *file, struct vm_area_struct *vma) +{ + struct shm_file_data *sfd = shm_file_data(file); + int ret; + + ret = sfd->file->f_op->mmap(sfd->file, vma); + if (ret != 0) + return ret; + sfd->vm_ops = vma->vm_ops; +#ifdef CONFIG_MMU + BUG_ON(!sfd->vm_ops->fault); +#endif + vma->vm_ops = &shm_vm_ops; + shm_open(vma); + + return ret; +} + +static int shm_release(struct inode *ino, struct file *file) +{ + struct shm_file_data *sfd = shm_file_data(file); + + put_ipc_ns(sfd->ns); + shm_file_data(file) = NULL; + kfree(sfd); + return 0; +} + +static int shm_fsync(struct file *file, loff_t start, loff_t end, int datasync) +{ + struct shm_file_data *sfd = shm_file_data(file); + + if (!sfd->file->f_op->fsync) + return -EINVAL; + return sfd->file->f_op->fsync(sfd->file, start, end, datasync); +} + +static long shm_fallocate(struct file *file, int mode, loff_t offset, + loff_t len) +{ + struct shm_file_data *sfd = shm_file_data(file); + + if (!sfd->file->f_op->fallocate) + return -EOPNOTSUPP; + return sfd->file->f_op->fallocate(file, mode, offset, len); +} + +static unsigned long shm_get_unmapped_area(struct file *file, + unsigned long addr, unsigned long len, unsigned long pgoff, + unsigned long flags) +{ + struct shm_file_data *sfd = shm_file_data(file); + return sfd->file->f_op->get_unmapped_area(sfd->file, addr, len, + pgoff, flags); +} + +static const struct file_operations shm_file_operations = { + .mmap = shm_mmap, + .fsync = shm_fsync, + .release = shm_release, +#ifndef CONFIG_MMU + .get_unmapped_area = shm_get_unmapped_area, +#endif + .llseek = noop_llseek, + .fallocate = shm_fallocate, +}; + +static const struct file_operations shm_file_operations_huge = { + .mmap = shm_mmap, + .fsync = shm_fsync, + .release = shm_release, + .get_unmapped_area = shm_get_unmapped_area, + .llseek = noop_llseek, + .fallocate = shm_fallocate, +}; + +int is_file_shm_hugepages(struct file *file) +{ + return file->f_op == &shm_file_operations_huge; +} + +static const struct vm_operations_struct shm_vm_ops = { + .open = shm_open, /* callback for a new vm-area open */ + .close = shm_close, /* callback for when the vm-area is released */ + .fault = shm_fault, +#if defined(CONFIG_NUMA) + .set_policy = shm_set_policy, + .get_policy = shm_get_policy, +#endif +}; + +/** + * newseg - Create a new shared memory segment + * @ns: namespace + * @params: ptr to the structure that contains key, size and shmflg + * + * Called with shm_ids.rwsem held as a writer. + */ +static int newseg(struct ipc_namespace *ns, struct ipc_params *params) +{ + key_t key = params->key; + int shmflg = params->flg; + size_t size = params->u.size; + int error; + struct shmid_kernel *shp; + size_t numpages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; + struct file *file; + char name[13]; + int id; + vm_flags_t acctflag = 0; + + if (size < SHMMIN || size > ns->shm_ctlmax) + return -EINVAL; + + if (numpages << PAGE_SHIFT < size) + return -ENOSPC; + + if (ns->shm_tot + numpages < ns->shm_tot || + ns->shm_tot + numpages > ns->shm_ctlall) + return -ENOSPC; + + shp = ipc_rcu_alloc(sizeof(*shp)); + if (!shp) + return -ENOMEM; + + shp->shm_perm.key = key; + shp->shm_perm.mode = (shmflg & S_IRWXUGO); + shp->mlock_user = NULL; + + shp->shm_perm.security = NULL; + error = security_shm_alloc(shp); + if (error) { + ipc_rcu_putref(shp, ipc_rcu_free); + return error; + } + + sprintf(name, "SYSV%08x", key); + if (shmflg & SHM_HUGETLB) { + struct hstate *hs; + size_t hugesize; + + hs = hstate_sizelog((shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK); + if (!hs) { + error = -EINVAL; + goto no_file; + } + hugesize = ALIGN(size, huge_page_size(hs)); + + /* hugetlb_file_setup applies strict accounting */ + if (shmflg & SHM_NORESERVE) + acctflag = VM_NORESERVE; + file = hugetlb_file_setup(name, hugesize, acctflag, + &shp->mlock_user, HUGETLB_SHMFS_INODE, + (shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK); + } else { + /* + * Do not allow no accounting for OVERCOMMIT_NEVER, even + * if it's asked for. + */ + if ((shmflg & SHM_NORESERVE) && + sysctl_overcommit_memory != OVERCOMMIT_NEVER) + acctflag = VM_NORESERVE; + file = shmem_file_setup(name, size, acctflag); + } + error = PTR_ERR(file); + if (IS_ERR(file)) + goto no_file; + + id = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni); + if (id < 0) { + error = id; + goto no_id; + } + + shp->shm_cprid = task_tgid_vnr(current); + shp->shm_lprid = 0; + shp->shm_atim = shp->shm_dtim = 0; + shp->shm_ctim = get_seconds(); + shp->shm_segsz = size; + shp->shm_nattch = 0; + shp->shm_file = file; + shp->shm_creator = current; + list_add(&shp->shm_clist, ¤t->sysvshm.shm_clist); + + /* + * shmid gets reported as "inode#" in /proc/pid/maps. + * proc-ps tools use this. Changing this will break them. + */ + file_inode(file)->i_ino = shp->shm_perm.id; + + ns->shm_tot += numpages; + error = shp->shm_perm.id; + + ipc_unlock_object(&shp->shm_perm); + rcu_read_unlock(); + return error; + +no_id: + if (is_file_hugepages(file) && shp->mlock_user) + user_shm_unlock(size, shp->mlock_user); + fput(file); +no_file: + ipc_rcu_putref(shp, shm_rcu_free); + return error; +} + +/* + * Called with shm_ids.rwsem and ipcp locked. + */ +static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg) +{ + struct shmid_kernel *shp; + + shp = container_of(ipcp, struct shmid_kernel, shm_perm); + return security_shm_associate(shp, shmflg); +} + +/* + * Called with shm_ids.rwsem and ipcp locked. + */ +static inline int shm_more_checks(struct kern_ipc_perm *ipcp, + struct ipc_params *params) +{ + struct shmid_kernel *shp; + + shp = container_of(ipcp, struct shmid_kernel, shm_perm); + if (shp->shm_segsz < params->u.size) + return -EINVAL; + + return 0; +} + +SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg) +{ + struct ipc_namespace *ns; + static const struct ipc_ops shm_ops = { + .getnew = newseg, + .associate = shm_security, + .more_checks = shm_more_checks, + }; + struct ipc_params shm_params; + + ns = current->nsproxy->ipc_ns; + + shm_params.key = key; + shm_params.flg = shmflg; + shm_params.u.size = size; + + return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params); +} + +static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version) +{ + switch (version) { + case IPC_64: + return copy_to_user(buf, in, sizeof(*in)); + case IPC_OLD: + { + struct shmid_ds out; + + memset(&out, 0, sizeof(out)); + ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm); + out.shm_segsz = in->shm_segsz; + out.shm_atime = in->shm_atime; + out.shm_dtime = in->shm_dtime; + out.shm_ctime = in->shm_ctime; + out.shm_cpid = in->shm_cpid; + out.shm_lpid = in->shm_lpid; + out.shm_nattch = in->shm_nattch; + + return copy_to_user(buf, &out, sizeof(out)); + } + default: + return -EINVAL; + } +} + +static inline unsigned long +copy_shmid_from_user(struct shmid64_ds *out, void __user *buf, int version) +{ + switch (version) { + case IPC_64: + if (copy_from_user(out, buf, sizeof(*out))) + return -EFAULT; + return 0; + case IPC_OLD: + { + struct shmid_ds tbuf_old; + + if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old))) + return -EFAULT; + + out->shm_perm.uid = tbuf_old.shm_perm.uid; + out->shm_perm.gid = tbuf_old.shm_perm.gid; + out->shm_perm.mode = tbuf_old.shm_perm.mode; + + return 0; + } + default: + return -EINVAL; + } +} + +static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version) +{ + switch (version) { + case IPC_64: + return copy_to_user(buf, in, sizeof(*in)); + case IPC_OLD: + { + struct shminfo out; + + if (in->shmmax > INT_MAX) + out.shmmax = INT_MAX; + else + out.shmmax = (int)in->shmmax; + + out.shmmin = in->shmmin; + out.shmmni = in->shmmni; + out.shmseg = in->shmseg; + out.shmall = in->shmall; + + return copy_to_user(buf, &out, sizeof(out)); + } + default: + return -EINVAL; + } +} + +/* + * Calculate and add used RSS and swap pages of a shm. + * Called with shm_ids.rwsem held as a reader + */ +static void shm_add_rss_swap(struct shmid_kernel *shp, + unsigned long *rss_add, unsigned long *swp_add) +{ + struct inode *inode; + + inode = file_inode(shp->shm_file); + + if (is_file_hugepages(shp->shm_file)) { + struct address_space *mapping = inode->i_mapping; + struct hstate *h = hstate_file(shp->shm_file); + *rss_add += pages_per_huge_page(h) * mapping->nrpages; + } else { +#ifdef CONFIG_SHMEM + struct shmem_inode_info *info = SHMEM_I(inode); + spin_lock(&info->lock); + *rss_add += inode->i_mapping->nrpages; + *swp_add += info->swapped; + spin_unlock(&info->lock); +#else + *rss_add += inode->i_mapping->nrpages; +#endif + } +} + +/* + * Called with shm_ids.rwsem held as a reader + */ +static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss, + unsigned long *swp) +{ + int next_id; + int total, in_use; + + *rss = 0; + *swp = 0; + + in_use = shm_ids(ns).in_use; + + for (total = 0, next_id = 0; total < in_use; next_id++) { + struct kern_ipc_perm *ipc; + struct shmid_kernel *shp; + + ipc = idr_find(&shm_ids(ns).ipcs_idr, next_id); + if (ipc == NULL) + continue; + shp = container_of(ipc, struct shmid_kernel, shm_perm); + + shm_add_rss_swap(shp, rss, swp); + + total++; + } +} + +/* + * This function handles some shmctl commands which require the rwsem + * to be held in write mode. + * NOTE: no locks must be held, the rwsem is taken inside this function. + */ +static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd, + struct shmid_ds __user *buf, int version) +{ + struct kern_ipc_perm *ipcp; + struct shmid64_ds shmid64; + struct shmid_kernel *shp; + int err; + + if (cmd == IPC_SET) { + if (copy_shmid_from_user(&shmid64, buf, version)) + return -EFAULT; + } + + down_write(&shm_ids(ns).rwsem); + rcu_read_lock(); + + ipcp = ipcctl_pre_down_nolock(ns, &shm_ids(ns), shmid, cmd, + &shmid64.shm_perm, 0); + if (IS_ERR(ipcp)) { + err = PTR_ERR(ipcp); + goto out_unlock1; + } + + shp = container_of(ipcp, struct shmid_kernel, shm_perm); + + err = security_shm_shmctl(shp, cmd); + if (err) + goto out_unlock1; + + switch (cmd) { + case IPC_RMID: + ipc_lock_object(&shp->shm_perm); + /* do_shm_rmid unlocks the ipc object and rcu */ + do_shm_rmid(ns, ipcp); + goto out_up; + case IPC_SET: + ipc_lock_object(&shp->shm_perm); + err = ipc_update_perm(&shmid64.shm_perm, ipcp); + if (err) + goto out_unlock0; + shp->shm_ctim = get_seconds(); + break; + default: + err = -EINVAL; + goto out_unlock1; + } + +out_unlock0: + ipc_unlock_object(&shp->shm_perm); +out_unlock1: + rcu_read_unlock(); +out_up: + up_write(&shm_ids(ns).rwsem); + return err; +} + +static int shmctl_nolock(struct ipc_namespace *ns, int shmid, + int cmd, int version, void __user *buf) +{ + int err; + struct shmid_kernel *shp; + + /* preliminary security checks for *_INFO */ + if (cmd == IPC_INFO || cmd == SHM_INFO) { + err = security_shm_shmctl(NULL, cmd); + if (err) + return err; + } + + switch (cmd) { + case IPC_INFO: + { + struct shminfo64 shminfo; + + memset(&shminfo, 0, sizeof(shminfo)); + shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni; + shminfo.shmmax = ns->shm_ctlmax; + shminfo.shmall = ns->shm_ctlall; + + shminfo.shmmin = SHMMIN; + if (copy_shminfo_to_user(buf, &shminfo, version)) + return -EFAULT; + + down_read(&shm_ids(ns).rwsem); + err = ipc_get_maxid(&shm_ids(ns)); + up_read(&shm_ids(ns).rwsem); + + if (err < 0) + err = 0; + goto out; + } + case SHM_INFO: + { + struct shm_info shm_info; + + memset(&shm_info, 0, sizeof(shm_info)); + down_read(&shm_ids(ns).rwsem); + shm_info.used_ids = shm_ids(ns).in_use; + shm_get_stat(ns, &shm_info.shm_rss, &shm_info.shm_swp); + shm_info.shm_tot = ns->shm_tot; + shm_info.swap_attempts = 0; + shm_info.swap_successes = 0; + err = ipc_get_maxid(&shm_ids(ns)); + up_read(&shm_ids(ns).rwsem); + if (copy_to_user(buf, &shm_info, sizeof(shm_info))) { + err = -EFAULT; + goto out; + } + + err = err < 0 ? 0 : err; + goto out; + } + case SHM_STAT: + case IPC_STAT: + { + struct shmid64_ds tbuf; + int result; + + rcu_read_lock(); + if (cmd == SHM_STAT) { + shp = shm_obtain_object(ns, shmid); + if (IS_ERR(shp)) { + err = PTR_ERR(shp); + goto out_unlock; + } + result = shp->shm_perm.id; + } else { + shp = shm_obtain_object_check(ns, shmid); + if (IS_ERR(shp)) { + err = PTR_ERR(shp); + goto out_unlock; + } + result = 0; + } + + err = -EACCES; + if (ipcperms(ns, &shp->shm_perm, S_IRUGO)) + goto out_unlock; + + err = security_shm_shmctl(shp, cmd); + if (err) + goto out_unlock; + + memset(&tbuf, 0, sizeof(tbuf)); + kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm); + tbuf.shm_segsz = shp->shm_segsz; + tbuf.shm_atime = shp->shm_atim; + tbuf.shm_dtime = shp->shm_dtim; + tbuf.shm_ctime = shp->shm_ctim; + tbuf.shm_cpid = shp->shm_cprid; + tbuf.shm_lpid = shp->shm_lprid; + tbuf.shm_nattch = shp->shm_nattch; + rcu_read_unlock(); + + if (copy_shmid_to_user(buf, &tbuf, version)) + err = -EFAULT; + else + err = result; + goto out; + } + default: + return -EINVAL; + } + +out_unlock: + rcu_read_unlock(); +out: + return err; +} + +SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf) +{ + struct shmid_kernel *shp; + int err, version; + struct ipc_namespace *ns; + + if (cmd < 0 || shmid < 0) + return -EINVAL; + + version = ipc_parse_version(&cmd); + ns = current->nsproxy->ipc_ns; + + switch (cmd) { + case IPC_INFO: + case SHM_INFO: + case SHM_STAT: + case IPC_STAT: + return shmctl_nolock(ns, shmid, cmd, version, buf); + case IPC_RMID: + case IPC_SET: + return shmctl_down(ns, shmid, cmd, buf, version); + case SHM_LOCK: + case SHM_UNLOCK: + { + struct file *shm_file; + + rcu_read_lock(); + shp = shm_obtain_object_check(ns, shmid); + if (IS_ERR(shp)) { + err = PTR_ERR(shp); + goto out_unlock1; + } + + audit_ipc_obj(&(shp->shm_perm)); + err = security_shm_shmctl(shp, cmd); + if (err) + goto out_unlock1; + + ipc_lock_object(&shp->shm_perm); + + /* check if shm_destroy() is tearing down shp */ + if (!ipc_valid_object(&shp->shm_perm)) { + err = -EIDRM; + goto out_unlock0; + } + + if (!ns_capable(ns->user_ns, CAP_IPC_LOCK)) { + kuid_t euid = current_euid(); + if (!uid_eq(euid, shp->shm_perm.uid) && + !uid_eq(euid, shp->shm_perm.cuid)) { + err = -EPERM; + goto out_unlock0; + } + if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK)) { + err = -EPERM; + goto out_unlock0; + } + } + + shm_file = shp->shm_file; + if (is_file_hugepages(shm_file)) + goto out_unlock0; + + if (cmd == SHM_LOCK) { + struct user_struct *user = current_user(); + err = shmem_lock(shm_file, 1, user); + if (!err && !(shp->shm_perm.mode & SHM_LOCKED)) { + shp->shm_perm.mode |= SHM_LOCKED; + shp->mlock_user = user; + } + goto out_unlock0; + } + + /* SHM_UNLOCK */ + if (!(shp->shm_perm.mode & SHM_LOCKED)) + goto out_unlock0; + shmem_lock(shm_file, 0, shp->mlock_user); + shp->shm_perm.mode &= ~SHM_LOCKED; + shp->mlock_user = NULL; + get_file(shm_file); + ipc_unlock_object(&shp->shm_perm); + rcu_read_unlock(); + shmem_unlock_mapping(shm_file->f_mapping); + + fput(shm_file); + return err; + } + default: + return -EINVAL; + } + +out_unlock0: + ipc_unlock_object(&shp->shm_perm); +out_unlock1: + rcu_read_unlock(); + return err; +} + +/* + * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists. + * + * NOTE! Despite the name, this is NOT a direct system call entrypoint. The + * "raddr" thing points to kernel space, and there has to be a wrapper around + * this. + */ +long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr, + unsigned long shmlba) +{ + struct shmid_kernel *shp; + unsigned long addr; + unsigned long size; + struct file *file; + int err; + unsigned long flags; + unsigned long prot; + int acc_mode; + struct ipc_namespace *ns; + struct shm_file_data *sfd; + struct path path; + fmode_t f_mode; + unsigned long populate = 0; + + err = -EINVAL; + if (shmid < 0) + goto out; + else if ((addr = (ulong)shmaddr)) { + if (addr & (shmlba - 1)) { + if (shmflg & SHM_RND) + addr &= ~(shmlba - 1); /* round down */ + else +#ifndef __ARCH_FORCE_SHMLBA + if (addr & ~PAGE_MASK) +#endif + goto out; + } + flags = MAP_SHARED | MAP_FIXED; + } else { + if ((shmflg & SHM_REMAP)) + goto out; + + flags = MAP_SHARED; + } + + if (shmflg & SHM_RDONLY) { + prot = PROT_READ; + acc_mode = S_IRUGO; + f_mode = FMODE_READ; + } else { + prot = PROT_READ | PROT_WRITE; + acc_mode = S_IRUGO | S_IWUGO; + f_mode = FMODE_READ | FMODE_WRITE; + } + if (shmflg & SHM_EXEC) { + prot |= PROT_EXEC; + acc_mode |= S_IXUGO; + } + + /* + * We cannot rely on the fs check since SYSV IPC does have an + * additional creator id... + */ + ns = current->nsproxy->ipc_ns; + rcu_read_lock(); + shp = shm_obtain_object_check(ns, shmid); + if (IS_ERR(shp)) { + err = PTR_ERR(shp); + goto out_unlock; + } + + err = -EACCES; + if (ipcperms(ns, &shp->shm_perm, acc_mode)) + goto out_unlock; + + err = security_shm_shmat(shp, shmaddr, shmflg); + if (err) + goto out_unlock; + + ipc_lock_object(&shp->shm_perm); + + /* check if shm_destroy() is tearing down shp */ + if (!ipc_valid_object(&shp->shm_perm)) { + ipc_unlock_object(&shp->shm_perm); + err = -EIDRM; + goto out_unlock; + } + + path = shp->shm_file->f_path; + path_get(&path); + shp->shm_nattch++; + size = i_size_read(d_inode(path.dentry)); + ipc_unlock_object(&shp->shm_perm); + rcu_read_unlock(); + + err = -ENOMEM; + sfd = kzalloc(sizeof(*sfd), GFP_KERNEL); + if (!sfd) { + path_put(&path); + goto out_nattch; + } + + file = alloc_file(&path, f_mode, + is_file_hugepages(shp->shm_file) ? + &shm_file_operations_huge : + &shm_file_operations); + err = PTR_ERR(file); + if (IS_ERR(file)) { + kfree(sfd); + path_put(&path); + goto out_nattch; + } + + file->private_data = sfd; + file->f_mapping = shp->shm_file->f_mapping; + sfd->id = shp->shm_perm.id; + sfd->ns = get_ipc_ns(ns); + sfd->file = shp->shm_file; + sfd->vm_ops = NULL; + + err = security_mmap_file(file, prot, flags); + if (err) + goto out_fput; + + down_write(¤t->mm->mmap_sem); + if (addr && !(shmflg & SHM_REMAP)) { + err = -EINVAL; + if (addr + size < addr) + goto invalid; + + if (find_vma_intersection(current->mm, addr, addr + size)) + goto invalid; + } + + addr = do_mmap_pgoff(file, addr, size, prot, flags, 0, &populate); + *raddr = addr; + err = 0; + if (IS_ERR_VALUE(addr)) + err = (long)addr; +invalid: + up_write(¤t->mm->mmap_sem); + if (populate) + mm_populate(addr, populate); + +out_fput: + fput(file); + +out_nattch: + down_write(&shm_ids(ns).rwsem); + shp = shm_lock(ns, shmid); + BUG_ON(IS_ERR(shp)); + shp->shm_nattch--; + if (shm_may_destroy(ns, shp)) + shm_destroy(ns, shp); + else + shm_unlock(shp); + up_write(&shm_ids(ns).rwsem); + return err; + +out_unlock: + rcu_read_unlock(); +out: + return err; +} + +SYSCALL_DEFINE3(shmat, int, shmid, char __user *, shmaddr, int, shmflg) +{ + unsigned long ret; + long err; + + err = do_shmat(shmid, shmaddr, shmflg, &ret, SHMLBA); + if (err) + return err; + force_successful_syscall_return(); + return (long)ret; +} + +/* + * detach and kill segment if marked destroyed. + * The work is done in shm_close. + */ +SYSCALL_DEFINE1(shmdt, char __user *, shmaddr) +{ + struct mm_struct *mm = current->mm; + struct vm_area_struct *vma; + unsigned long addr = (unsigned long)shmaddr; + int retval = -EINVAL; +#ifdef CONFIG_MMU + loff_t size = 0; + struct file *file; + struct vm_area_struct *next; +#endif + + if (addr & ~PAGE_MASK) + return retval; + + down_write(&mm->mmap_sem); + + /* + * This function tries to be smart and unmap shm segments that + * were modified by partial mlock or munmap calls: + * - It first determines the size of the shm segment that should be + * unmapped: It searches for a vma that is backed by shm and that + * started at address shmaddr. It records it's size and then unmaps + * it. + * - Then it unmaps all shm vmas that started at shmaddr and that + * are within the initially determined size and that are from the + * same shm segment from which we determined the size. + * Errors from do_munmap are ignored: the function only fails if + * it's called with invalid parameters or if it's called to unmap + * a part of a vma. Both calls in this function are for full vmas, + * the parameters are directly copied from the vma itself and always + * valid - therefore do_munmap cannot fail. (famous last words?) + */ + /* + * If it had been mremap()'d, the starting address would not + * match the usual checks anyway. So assume all vma's are + * above the starting address given. + */ + vma = find_vma(mm, addr); + +#ifdef CONFIG_MMU + while (vma) { + next = vma->vm_next; + + /* + * Check if the starting address would match, i.e. it's + * a fragment created by mprotect() and/or munmap(), or it + * otherwise it starts at this address with no hassles. + */ + if ((vma->vm_ops == &shm_vm_ops) && + (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) { + + /* + * Record the file of the shm segment being + * unmapped. With mremap(), someone could place + * page from another segment but with equal offsets + * in the range we are unmapping. + */ + file = vma->vm_file; + size = i_size_read(file_inode(vma->vm_file)); + do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start); + /* + * We discovered the size of the shm segment, so + * break out of here and fall through to the next + * loop that uses the size information to stop + * searching for matching vma's. + */ + retval = 0; + vma = next; + break; + } + vma = next; + } + + /* + * We need look no further than the maximum address a fragment + * could possibly have landed at. Also cast things to loff_t to + * prevent overflows and make comparisons vs. equal-width types. + */ + size = PAGE_ALIGN(size); + while (vma && (loff_t)(vma->vm_end - addr) <= size) { + next = vma->vm_next; + + /* finding a matching vma now does not alter retval */ + if ((vma->vm_ops == &shm_vm_ops) && + ((vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) && + (vma->vm_file == file)) + do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start); + vma = next; + } + +#else /* CONFIG_MMU */ + /* under NOMMU conditions, the exact address to be destroyed must be + * given */ + if (vma && vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) { + do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start); + retval = 0; + } + +#endif + + up_write(&mm->mmap_sem); + return retval; +} + +#ifdef CONFIG_PROC_FS +static int sysvipc_shm_proc_show(struct seq_file *s, void *it) +{ + struct user_namespace *user_ns = seq_user_ns(s); + struct shmid_kernel *shp = it; + unsigned long rss = 0, swp = 0; + + shm_add_rss_swap(shp, &rss, &swp); + +#if BITS_PER_LONG <= 32 +#define SIZE_SPEC "%10lu" +#else +#define SIZE_SPEC "%21lu" +#endif + + seq_printf(s, + "%10d %10d %4o " SIZE_SPEC " %5u %5u " + "%5lu %5u %5u %5u %5u %10lu %10lu %10lu " + SIZE_SPEC " " SIZE_SPEC "\n", + shp->shm_perm.key, + shp->shm_perm.id, + shp->shm_perm.mode, + shp->shm_segsz, + shp->shm_cprid, + shp->shm_lprid, + shp->shm_nattch, + from_kuid_munged(user_ns, shp->shm_perm.uid), + from_kgid_munged(user_ns, shp->shm_perm.gid), + from_kuid_munged(user_ns, shp->shm_perm.cuid), + from_kgid_munged(user_ns, shp->shm_perm.cgid), + shp->shm_atim, + shp->shm_dtim, + shp->shm_ctim, + rss * PAGE_SIZE, + swp * PAGE_SIZE); + + return 0; +} +#endif diff --git a/kernel/ipc/syscall.c b/kernel/ipc/syscall.c new file mode 100644 index 000000000..52429489c --- /dev/null +++ b/kernel/ipc/syscall.c @@ -0,0 +1,99 @@ +/* + * sys_ipc() is the old de-multiplexer for the SysV IPC calls. + * + * This is really horribly ugly, and new architectures should just wire up + * the individual syscalls instead. + */ +#include + +#ifdef __ARCH_WANT_SYS_IPC +#include +#include +#include +#include +#include + +SYSCALL_DEFINE6(ipc, unsigned int, call, int, first, unsigned long, second, + unsigned long, third, void __user *, ptr, long, fifth) +{ + int version, ret; + + version = call >> 16; /* hack for backward compatibility */ + call &= 0xffff; + + switch (call) { + case SEMOP: + return sys_semtimedop(first, (struct sembuf __user *)ptr, + second, NULL); + case SEMTIMEDOP: + return sys_semtimedop(first, (struct sembuf __user *)ptr, + second, + (const struct timespec __user *)fifth); + + case SEMGET: + return sys_semget(first, second, third); + case SEMCTL: { + unsigned long arg; + if (!ptr) + return -EINVAL; + if (get_user(arg, (unsigned long __user *) ptr)) + return -EFAULT; + return sys_semctl(first, second, third, arg); + } + + case MSGSND: + return sys_msgsnd(first, (struct msgbuf __user *) ptr, + second, third); + case MSGRCV: + switch (version) { + case 0: { + struct ipc_kludge tmp; + if (!ptr) + return -EINVAL; + + if (copy_from_user(&tmp, + (struct ipc_kludge __user *) ptr, + sizeof(tmp))) + return -EFAULT; + return sys_msgrcv(first, tmp.msgp, second, + tmp.msgtyp, third); + } + default: + return sys_msgrcv(first, + (struct msgbuf __user *) ptr, + second, fifth, third); + } + case MSGGET: + return sys_msgget((key_t) first, second); + case MSGCTL: + return sys_msgctl(first, second, (struct msqid_ds __user *)ptr); + + case SHMAT: + switch (version) { + default: { + unsigned long raddr; + ret = do_shmat(first, (char __user *)ptr, + second, &raddr, SHMLBA); + if (ret) + return ret; + return put_user(raddr, (unsigned long __user *) third); + } + case 1: + /* + * This was the entry point for kernel-originating calls + * from iBCS2 in 2.2 days. + */ + return -EINVAL; + } + case SHMDT: + return sys_shmdt((char __user *)ptr); + case SHMGET: + return sys_shmget(first, second, third); + case SHMCTL: + return sys_shmctl(first, second, + (struct shmid_ds __user *) ptr); + default: + return -ENOSYS; + } +} +#endif diff --git a/kernel/ipc/util.c b/kernel/ipc/util.c new file mode 100644 index 000000000..ff3323ef8 --- /dev/null +++ b/kernel/ipc/util.c @@ -0,0 +1,883 @@ +/* + * linux/ipc/util.c + * Copyright (C) 1992 Krishna Balasubramanian + * + * Sep 1997 - Call suser() last after "normal" permission checks so we + * get BSD style process accounting right. + * Occurs in several places in the IPC code. + * Chris Evans, + * Nov 1999 - ipc helper functions, unified SMP locking + * Manfred Spraul + * Oct 2002 - One lock per IPC id. RCU ipc_free for lock-free grow_ary(). + * Mingming Cao + * Mar 2006 - support for audit of ipc object properties + * Dustin Kirkland + * Jun 2006 - namespaces ssupport + * OpenVZ, SWsoft Inc. + * Pavel Emelianov + * + * General sysv ipc locking scheme: + * rcu_read_lock() + * obtain the ipc object (kern_ipc_perm) by looking up the id in an idr + * tree. + * - perform initial checks (capabilities, auditing and permission, + * etc). + * - perform read-only operations, such as STAT, INFO commands. + * acquire the ipc lock (kern_ipc_perm.lock) through + * ipc_lock_object() + * - perform data updates, such as SET, RMID commands and + * mechanism-specific operations (semop/semtimedop, + * msgsnd/msgrcv, shmat/shmdt). + * drop the ipc lock, through ipc_unlock_object(). + * rcu_read_unlock() + * + * The ids->rwsem must be taken when: + * - creating, removing and iterating the existing entries in ipc + * identifier sets. + * - iterating through files under /proc/sysvipc/ + * + * Note that sems have a special fast path that avoids kern_ipc_perm.lock - + * see sem_lock(). + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +#include "util.h" + +struct ipc_proc_iface { + const char *path; + const char *header; + int ids; + int (*show)(struct seq_file *, void *); +}; + +/** + * ipc_init - initialise ipc subsystem + * + * The various sysv ipc resources (semaphores, messages and shared + * memory) are initialised. + * + * A callback routine is registered into the memory hotplug notifier + * chain: since msgmni scales to lowmem this callback routine will be + * called upon successful memory add / remove to recompute msmgni. + */ +static int __init ipc_init(void) +{ + sem_init(); + msg_init(); + shm_init(); + return 0; +} +device_initcall(ipc_init); + +/** + * ipc_init_ids - initialise ipc identifiers + * @ids: ipc identifier set + * + * Set up the sequence range to use for the ipc identifier range (limited + * below IPCMNI) then initialise the ids idr. + */ +void ipc_init_ids(struct ipc_ids *ids) +{ + ids->in_use = 0; + ids->seq = 0; + ids->next_id = -1; + init_rwsem(&ids->rwsem); + idr_init(&ids->ipcs_idr); +} + +#ifdef CONFIG_PROC_FS +static const struct file_operations sysvipc_proc_fops; +/** + * ipc_init_proc_interface - create a proc interface for sysipc types using a seq_file interface. + * @path: Path in procfs + * @header: Banner to be printed at the beginning of the file. + * @ids: ipc id table to iterate. + * @show: show routine. + */ +void __init ipc_init_proc_interface(const char *path, const char *header, + int ids, int (*show)(struct seq_file *, void *)) +{ + struct proc_dir_entry *pde; + struct ipc_proc_iface *iface; + + iface = kmalloc(sizeof(*iface), GFP_KERNEL); + if (!iface) + return; + iface->path = path; + iface->header = header; + iface->ids = ids; + iface->show = show; + + pde = proc_create_data(path, + S_IRUGO, /* world readable */ + NULL, /* parent dir */ + &sysvipc_proc_fops, + iface); + if (!pde) + kfree(iface); +} +#endif + +/** + * ipc_findkey - find a key in an ipc identifier set + * @ids: ipc identifier set + * @key: key to find + * + * Returns the locked pointer to the ipc structure if found or NULL + * otherwise. If key is found ipc points to the owning ipc structure + * + * Called with ipc_ids.rwsem held. + */ +static struct kern_ipc_perm *ipc_findkey(struct ipc_ids *ids, key_t key) +{ + struct kern_ipc_perm *ipc; + int next_id; + int total; + + for (total = 0, next_id = 0; total < ids->in_use; next_id++) { + ipc = idr_find(&ids->ipcs_idr, next_id); + + if (ipc == NULL) + continue; + + if (ipc->key != key) { + total++; + continue; + } + + rcu_read_lock(); + ipc_lock_object(ipc); + return ipc; + } + + return NULL; +} + +/** + * ipc_get_maxid - get the last assigned id + * @ids: ipc identifier set + * + * Called with ipc_ids.rwsem held. + */ +int ipc_get_maxid(struct ipc_ids *ids) +{ + struct kern_ipc_perm *ipc; + int max_id = -1; + int total, id; + + if (ids->in_use == 0) + return -1; + + if (ids->in_use == IPCMNI) + return IPCMNI - 1; + + /* Look for the last assigned id */ + total = 0; + for (id = 0; id < IPCMNI && total < ids->in_use; id++) { + ipc = idr_find(&ids->ipcs_idr, id); + if (ipc != NULL) { + max_id = id; + total++; + } + } + return max_id; +} + +/** + * ipc_addid - add an ipc identifier + * @ids: ipc identifier set + * @new: new ipc permission set + * @size: limit for the number of used ids + * + * Add an entry 'new' to the ipc ids idr. The permissions object is + * initialised and the first free entry is set up and the id assigned + * is returned. The 'new' entry is returned in a locked state on success. + * On failure the entry is not locked and a negative err-code is returned. + * + * Called with writer ipc_ids.rwsem held. + */ +int ipc_addid(struct ipc_ids *ids, struct kern_ipc_perm *new, int size) +{ + kuid_t euid; + kgid_t egid; + int id; + int next_id = ids->next_id; + + if (size > IPCMNI) + size = IPCMNI; + + if (ids->in_use >= size) + return -ENOSPC; + + idr_preload(GFP_KERNEL); + + spin_lock_init(&new->lock); + new->deleted = false; + rcu_read_lock(); + spin_lock(&new->lock); + + id = idr_alloc(&ids->ipcs_idr, new, + (next_id < 0) ? 0 : ipcid_to_idx(next_id), 0, + GFP_NOWAIT); + idr_preload_end(); + if (id < 0) { + spin_unlock(&new->lock); + rcu_read_unlock(); + return id; + } + + ids->in_use++; + + current_euid_egid(&euid, &egid); + new->cuid = new->uid = euid; + new->gid = new->cgid = egid; + + if (next_id < 0) { + new->seq = ids->seq++; + if (ids->seq > IPCID_SEQ_MAX) + ids->seq = 0; + } else { + new->seq = ipcid_to_seqx(next_id); + ids->next_id = -1; + } + + new->id = ipc_buildid(id, new->seq); + return id; +} + +/** + * ipcget_new - create a new ipc object + * @ns: ipc namespace + * @ids: ipc identifier set + * @ops: the actual creation routine to call + * @params: its parameters + * + * This routine is called by sys_msgget, sys_semget() and sys_shmget() + * when the key is IPC_PRIVATE. + */ +static int ipcget_new(struct ipc_namespace *ns, struct ipc_ids *ids, + const struct ipc_ops *ops, struct ipc_params *params) +{ + int err; + + down_write(&ids->rwsem); + err = ops->getnew(ns, params); + up_write(&ids->rwsem); + return err; +} + +/** + * ipc_check_perms - check security and permissions for an ipc object + * @ns: ipc namespace + * @ipcp: ipc permission set + * @ops: the actual security routine to call + * @params: its parameters + * + * This routine is called by sys_msgget(), sys_semget() and sys_shmget() + * when the key is not IPC_PRIVATE and that key already exists in the + * ds IDR. + * + * On success, the ipc id is returned. + * + * It is called with ipc_ids.rwsem and ipcp->lock held. + */ +static int ipc_check_perms(struct ipc_namespace *ns, + struct kern_ipc_perm *ipcp, + const struct ipc_ops *ops, + struct ipc_params *params) +{ + int err; + + if (ipcperms(ns, ipcp, params->flg)) + err = -EACCES; + else { + err = ops->associate(ipcp, params->flg); + if (!err) + err = ipcp->id; + } + + return err; +} + +/** + * ipcget_public - get an ipc object or create a new one + * @ns: ipc namespace + * @ids: ipc identifier set + * @ops: the actual creation routine to call + * @params: its parameters + * + * This routine is called by sys_msgget, sys_semget() and sys_shmget() + * when the key is not IPC_PRIVATE. + * It adds a new entry if the key is not found and does some permission + * / security checkings if the key is found. + * + * On success, the ipc id is returned. + */ +static int ipcget_public(struct ipc_namespace *ns, struct ipc_ids *ids, + const struct ipc_ops *ops, struct ipc_params *params) +{ + struct kern_ipc_perm *ipcp; + int flg = params->flg; + int err; + + /* + * Take the lock as a writer since we are potentially going to add + * a new entry + read locks are not "upgradable" + */ + down_write(&ids->rwsem); + ipcp = ipc_findkey(ids, params->key); + if (ipcp == NULL) { + /* key not used */ + if (!(flg & IPC_CREAT)) + err = -ENOENT; + else + err = ops->getnew(ns, params); + } else { + /* ipc object has been locked by ipc_findkey() */ + + if (flg & IPC_CREAT && flg & IPC_EXCL) + err = -EEXIST; + else { + err = 0; + if (ops->more_checks) + err = ops->more_checks(ipcp, params); + if (!err) + /* + * ipc_check_perms returns the IPC id on + * success + */ + err = ipc_check_perms(ns, ipcp, ops, params); + } + ipc_unlock(ipcp); + } + up_write(&ids->rwsem); + + return err; +} + + +/** + * ipc_rmid - remove an ipc identifier + * @ids: ipc identifier set + * @ipcp: ipc perm structure containing the identifier to remove + * + * ipc_ids.rwsem (as a writer) and the spinlock for this ID are held + * before this function is called, and remain locked on the exit. + */ +void ipc_rmid(struct ipc_ids *ids, struct kern_ipc_perm *ipcp) +{ + int lid = ipcid_to_idx(ipcp->id); + + idr_remove(&ids->ipcs_idr, lid); + ids->in_use--; + ipcp->deleted = true; +} + +/** + * ipc_alloc - allocate ipc space + * @size: size desired + * + * Allocate memory from the appropriate pools and return a pointer to it. + * NULL is returned if the allocation fails + */ +void *ipc_alloc(int size) +{ + void *out; + if (size > PAGE_SIZE) + out = vmalloc(size); + else + out = kmalloc(size, GFP_KERNEL); + return out; +} + +/** + * ipc_free - free ipc space + * @ptr: pointer returned by ipc_alloc + * @size: size of block + * + * Free a block created with ipc_alloc(). The caller must know the size + * used in the allocation call. + */ +void ipc_free(void *ptr, int size) +{ + if (size > PAGE_SIZE) + vfree(ptr); + else + kfree(ptr); +} + +/** + * ipc_rcu_alloc - allocate ipc and rcu space + * @size: size desired + * + * Allocate memory for the rcu header structure + the object. + * Returns the pointer to the object or NULL upon failure. + */ +void *ipc_rcu_alloc(int size) +{ + /* + * We prepend the allocation with the rcu struct + */ + struct ipc_rcu *out = ipc_alloc(sizeof(struct ipc_rcu) + size); + if (unlikely(!out)) + return NULL; + atomic_set(&out->refcount, 1); + return out + 1; +} + +int ipc_rcu_getref(void *ptr) +{ + struct ipc_rcu *p = ((struct ipc_rcu *)ptr) - 1; + + return atomic_inc_not_zero(&p->refcount); +} + +void ipc_rcu_putref(void *ptr, void (*func)(struct rcu_head *head)) +{ + struct ipc_rcu *p = ((struct ipc_rcu *)ptr) - 1; + + if (!atomic_dec_and_test(&p->refcount)) + return; + + call_rcu(&p->rcu, func); +} + +void ipc_rcu_free(struct rcu_head *head) +{ + struct ipc_rcu *p = container_of(head, struct ipc_rcu, rcu); + + if (is_vmalloc_addr(p)) + vfree(p); + else + kfree(p); +} + +/** + * ipcperms - check ipc permissions + * @ns: ipc namespace + * @ipcp: ipc permission set + * @flag: desired permission set + * + * Check user, group, other permissions for access + * to ipc resources. return 0 if allowed + * + * @flag will most probably be 0 or S_...UGO from + */ +int ipcperms(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp, short flag) +{ + kuid_t euid = current_euid(); + int requested_mode, granted_mode; + + audit_ipc_obj(ipcp); + requested_mode = (flag >> 6) | (flag >> 3) | flag; + granted_mode = ipcp->mode; + if (uid_eq(euid, ipcp->cuid) || + uid_eq(euid, ipcp->uid)) + granted_mode >>= 6; + else if (in_group_p(ipcp->cgid) || in_group_p(ipcp->gid)) + granted_mode >>= 3; + /* is there some bit set in requested_mode but not in granted_mode? */ + if ((requested_mode & ~granted_mode & 0007) && + !ns_capable(ns->user_ns, CAP_IPC_OWNER)) + return -1; + + return security_ipc_permission(ipcp, flag); +} + +/* + * Functions to convert between the kern_ipc_perm structure and the + * old/new ipc_perm structures + */ + +/** + * kernel_to_ipc64_perm - convert kernel ipc permissions to user + * @in: kernel permissions + * @out: new style ipc permissions + * + * Turn the kernel object @in into a set of permissions descriptions + * for returning to userspace (@out). + */ +void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out) +{ + out->key = in->key; + out->uid = from_kuid_munged(current_user_ns(), in->uid); + out->gid = from_kgid_munged(current_user_ns(), in->gid); + out->cuid = from_kuid_munged(current_user_ns(), in->cuid); + out->cgid = from_kgid_munged(current_user_ns(), in->cgid); + out->mode = in->mode; + out->seq = in->seq; +} + +/** + * ipc64_perm_to_ipc_perm - convert new ipc permissions to old + * @in: new style ipc permissions + * @out: old style ipc permissions + * + * Turn the new style permissions object @in into a compatibility + * object and store it into the @out pointer. + */ +void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out) +{ + out->key = in->key; + SET_UID(out->uid, in->uid); + SET_GID(out->gid, in->gid); + SET_UID(out->cuid, in->cuid); + SET_GID(out->cgid, in->cgid); + out->mode = in->mode; + out->seq = in->seq; +} + +/** + * ipc_obtain_object + * @ids: ipc identifier set + * @id: ipc id to look for + * + * Look for an id in the ipc ids idr and return associated ipc object. + * + * Call inside the RCU critical section. + * The ipc object is *not* locked on exit. + */ +struct kern_ipc_perm *ipc_obtain_object(struct ipc_ids *ids, int id) +{ + struct kern_ipc_perm *out; + int lid = ipcid_to_idx(id); + + out = idr_find(&ids->ipcs_idr, lid); + if (!out) + return ERR_PTR(-EINVAL); + + return out; +} + +/** + * ipc_lock - lock an ipc structure without rwsem held + * @ids: ipc identifier set + * @id: ipc id to look for + * + * Look for an id in the ipc ids idr and lock the associated ipc object. + * + * The ipc object is locked on successful exit. + */ +struct kern_ipc_perm *ipc_lock(struct ipc_ids *ids, int id) +{ + struct kern_ipc_perm *out; + + rcu_read_lock(); + out = ipc_obtain_object(ids, id); + if (IS_ERR(out)) + goto err1; + + spin_lock(&out->lock); + + /* ipc_rmid() may have already freed the ID while ipc_lock + * was spinning: here verify that the structure is still valid + */ + if (ipc_valid_object(out)) + return out; + + spin_unlock(&out->lock); + out = ERR_PTR(-EINVAL); +err1: + rcu_read_unlock(); + return out; +} + +/** + * ipc_obtain_object_check + * @ids: ipc identifier set + * @id: ipc id to look for + * + * Similar to ipc_obtain_object() but also checks + * the ipc object reference counter. + * + * Call inside the RCU critical section. + * The ipc object is *not* locked on exit. + */ +struct kern_ipc_perm *ipc_obtain_object_check(struct ipc_ids *ids, int id) +{ + struct kern_ipc_perm *out = ipc_obtain_object(ids, id); + + if (IS_ERR(out)) + goto out; + + if (ipc_checkid(out, id)) + return ERR_PTR(-EIDRM); +out: + return out; +} + +/** + * ipcget - Common sys_*get() code + * @ns: namespace + * @ids: ipc identifier set + * @ops: operations to be called on ipc object creation, permission checks + * and further checks + * @params: the parameters needed by the previous operations. + * + * Common routine called by sys_msgget(), sys_semget() and sys_shmget(). + */ +int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids, + const struct ipc_ops *ops, struct ipc_params *params) +{ + if (params->key == IPC_PRIVATE) + return ipcget_new(ns, ids, ops, params); + else + return ipcget_public(ns, ids, ops, params); +} + +/** + * ipc_update_perm - update the permissions of an ipc object + * @in: the permission given as input. + * @out: the permission of the ipc to set. + */ +int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out) +{ + kuid_t uid = make_kuid(current_user_ns(), in->uid); + kgid_t gid = make_kgid(current_user_ns(), in->gid); + if (!uid_valid(uid) || !gid_valid(gid)) + return -EINVAL; + + out->uid = uid; + out->gid = gid; + out->mode = (out->mode & ~S_IRWXUGO) + | (in->mode & S_IRWXUGO); + + return 0; +} + +/** + * ipcctl_pre_down_nolock - retrieve an ipc and check permissions for some IPC_XXX cmd + * @ns: ipc namespace + * @ids: the table of ids where to look for the ipc + * @id: the id of the ipc to retrieve + * @cmd: the cmd to check + * @perm: the permission to set + * @extra_perm: one extra permission parameter used by msq + * + * This function does some common audit and permissions check for some IPC_XXX + * cmd and is called from semctl_down, shmctl_down and msgctl_down. + * It must be called without any lock held and + * - retrieves the ipc with the given id in the given table. + * - performs some audit and permission check, depending on the given cmd + * - returns a pointer to the ipc object or otherwise, the corresponding error. + * + * Call holding the both the rwsem and the rcu read lock. + */ +struct kern_ipc_perm *ipcctl_pre_down_nolock(struct ipc_namespace *ns, + struct ipc_ids *ids, int id, int cmd, + struct ipc64_perm *perm, int extra_perm) +{ + kuid_t euid; + int err = -EPERM; + struct kern_ipc_perm *ipcp; + + ipcp = ipc_obtain_object_check(ids, id); + if (IS_ERR(ipcp)) { + err = PTR_ERR(ipcp); + goto err; + } + + audit_ipc_obj(ipcp); + if (cmd == IPC_SET) + audit_ipc_set_perm(extra_perm, perm->uid, + perm->gid, perm->mode); + + euid = current_euid(); + if (uid_eq(euid, ipcp->cuid) || uid_eq(euid, ipcp->uid) || + ns_capable(ns->user_ns, CAP_SYS_ADMIN)) + return ipcp; /* successful lookup */ +err: + return ERR_PTR(err); +} + +#ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION + + +/** + * ipc_parse_version - ipc call version + * @cmd: pointer to command + * + * Return IPC_64 for new style IPC and IPC_OLD for old style IPC. + * The @cmd value is turned from an encoding command and version into + * just the command code. + */ +int ipc_parse_version(int *cmd) +{ + if (*cmd & IPC_64) { + *cmd ^= IPC_64; + return IPC_64; + } else { + return IPC_OLD; + } +} + +#endif /* CONFIG_ARCH_WANT_IPC_PARSE_VERSION */ + +#ifdef CONFIG_PROC_FS +struct ipc_proc_iter { + struct ipc_namespace *ns; + struct ipc_proc_iface *iface; +}; + +/* + * This routine locks the ipc structure found at least at position pos. + */ +static struct kern_ipc_perm *sysvipc_find_ipc(struct ipc_ids *ids, loff_t pos, + loff_t *new_pos) +{ + struct kern_ipc_perm *ipc; + int total, id; + + total = 0; + for (id = 0; id < pos && total < ids->in_use; id++) { + ipc = idr_find(&ids->ipcs_idr, id); + if (ipc != NULL) + total++; + } + + if (total >= ids->in_use) + return NULL; + + for (; pos < IPCMNI; pos++) { + ipc = idr_find(&ids->ipcs_idr, pos); + if (ipc != NULL) { + *new_pos = pos + 1; + rcu_read_lock(); + ipc_lock_object(ipc); + return ipc; + } + } + + /* Out of range - return NULL to terminate iteration */ + return NULL; +} + +static void *sysvipc_proc_next(struct seq_file *s, void *it, loff_t *pos) +{ + struct ipc_proc_iter *iter = s->private; + struct ipc_proc_iface *iface = iter->iface; + struct kern_ipc_perm *ipc = it; + + /* If we had an ipc id locked before, unlock it */ + if (ipc && ipc != SEQ_START_TOKEN) + ipc_unlock(ipc); + + return sysvipc_find_ipc(&iter->ns->ids[iface->ids], *pos, pos); +} + +/* + * File positions: pos 0 -> header, pos n -> ipc id = n - 1. + * SeqFile iterator: iterator value locked ipc pointer or SEQ_TOKEN_START. + */ +static void *sysvipc_proc_start(struct seq_file *s, loff_t *pos) +{ + struct ipc_proc_iter *iter = s->private; + struct ipc_proc_iface *iface = iter->iface; + struct ipc_ids *ids; + + ids = &iter->ns->ids[iface->ids]; + + /* + * Take the lock - this will be released by the corresponding + * call to stop(). + */ + down_read(&ids->rwsem); + + /* pos < 0 is invalid */ + if (*pos < 0) + return NULL; + + /* pos == 0 means header */ + if (*pos == 0) + return SEQ_START_TOKEN; + + /* Find the (pos-1)th ipc */ + return sysvipc_find_ipc(ids, *pos - 1, pos); +} + +static void sysvipc_proc_stop(struct seq_file *s, void *it) +{ + struct kern_ipc_perm *ipc = it; + struct ipc_proc_iter *iter = s->private; + struct ipc_proc_iface *iface = iter->iface; + struct ipc_ids *ids; + + /* If we had a locked structure, release it */ + if (ipc && ipc != SEQ_START_TOKEN) + ipc_unlock(ipc); + + ids = &iter->ns->ids[iface->ids]; + /* Release the lock we took in start() */ + up_read(&ids->rwsem); +} + +static int sysvipc_proc_show(struct seq_file *s, void *it) +{ + struct ipc_proc_iter *iter = s->private; + struct ipc_proc_iface *iface = iter->iface; + + if (it == SEQ_START_TOKEN) { + seq_puts(s, iface->header); + return 0; + } + + return iface->show(s, it); +} + +static const struct seq_operations sysvipc_proc_seqops = { + .start = sysvipc_proc_start, + .stop = sysvipc_proc_stop, + .next = sysvipc_proc_next, + .show = sysvipc_proc_show, +}; + +static int sysvipc_proc_open(struct inode *inode, struct file *file) +{ + struct ipc_proc_iter *iter; + + iter = __seq_open_private(file, &sysvipc_proc_seqops, sizeof(*iter)); + if (!iter) + return -ENOMEM; + + iter->iface = PDE_DATA(inode); + iter->ns = get_ipc_ns(current->nsproxy->ipc_ns); + + return 0; +} + +static int sysvipc_proc_release(struct inode *inode, struct file *file) +{ + struct seq_file *seq = file->private_data; + struct ipc_proc_iter *iter = seq->private; + put_ipc_ns(iter->ns); + return seq_release_private(inode, file); +} + +static const struct file_operations sysvipc_proc_fops = { + .open = sysvipc_proc_open, + .read = seq_read, + .llseek = seq_lseek, + .release = sysvipc_proc_release, +}; +#endif /* CONFIG_PROC_FS */ diff --git a/kernel/ipc/util.h b/kernel/ipc/util.h new file mode 100644 index 000000000..1a5a0fcd0 --- /dev/null +++ b/kernel/ipc/util.h @@ -0,0 +1,207 @@ +/* + * linux/ipc/util.h + * Copyright (C) 1999 Christoph Rohland + * + * ipc helper functions (c) 1999 Manfred Spraul + * namespaces support. 2006 OpenVZ, SWsoft Inc. + * Pavel Emelianov + */ + +#ifndef _IPC_UTIL_H +#define _IPC_UTIL_H + +#include +#include + +#define SEQ_MULTIPLIER (IPCMNI) + +void sem_init(void); +void msg_init(void); +void shm_init(void); + +struct ipc_namespace; + +#ifdef CONFIG_POSIX_MQUEUE +extern void mq_clear_sbinfo(struct ipc_namespace *ns); +extern void mq_put_mnt(struct ipc_namespace *ns); +#else +static inline void mq_clear_sbinfo(struct ipc_namespace *ns) { } +static inline void mq_put_mnt(struct ipc_namespace *ns) { } +#endif + +#ifdef CONFIG_SYSVIPC +void sem_init_ns(struct ipc_namespace *ns); +void msg_init_ns(struct ipc_namespace *ns); +void shm_init_ns(struct ipc_namespace *ns); + +void sem_exit_ns(struct ipc_namespace *ns); +void msg_exit_ns(struct ipc_namespace *ns); +void shm_exit_ns(struct ipc_namespace *ns); +#else +static inline void sem_init_ns(struct ipc_namespace *ns) { } +static inline void msg_init_ns(struct ipc_namespace *ns) { } +static inline void shm_init_ns(struct ipc_namespace *ns) { } + +static inline void sem_exit_ns(struct ipc_namespace *ns) { } +static inline void msg_exit_ns(struct ipc_namespace *ns) { } +static inline void shm_exit_ns(struct ipc_namespace *ns) { } +#endif + +struct ipc_rcu { + struct rcu_head rcu; + atomic_t refcount; +} ____cacheline_aligned_in_smp; + +#define ipc_rcu_to_struct(p) ((void *)(p+1)) + +/* + * Structure that holds the parameters needed by the ipc operations + * (see after) + */ +struct ipc_params { + key_t key; + int flg; + union { + size_t size; /* for shared memories */ + int nsems; /* for semaphores */ + } u; /* holds the getnew() specific param */ +}; + +/* + * Structure that holds some ipc operations. This structure is used to unify + * the calls to sys_msgget(), sys_semget(), sys_shmget() + * . routine to call to create a new ipc object. Can be one of newque, + * newary, newseg + * . routine to call to check permissions for a new ipc object. + * Can be one of security_msg_associate, security_sem_associate, + * security_shm_associate + * . routine to call for an extra check if needed + */ +struct ipc_ops { + int (*getnew)(struct ipc_namespace *, struct ipc_params *); + int (*associate)(struct kern_ipc_perm *, int); + int (*more_checks)(struct kern_ipc_perm *, struct ipc_params *); +}; + +struct seq_file; +struct ipc_ids; + +void ipc_init_ids(struct ipc_ids *); +#ifdef CONFIG_PROC_FS +void __init ipc_init_proc_interface(const char *path, const char *header, + int ids, int (*show)(struct seq_file *, void *)); +#else +#define ipc_init_proc_interface(path, header, ids, show) do {} while (0) +#endif + +#define IPC_SEM_IDS 0 +#define IPC_MSG_IDS 1 +#define IPC_SHM_IDS 2 + +#define ipcid_to_idx(id) ((id) % SEQ_MULTIPLIER) +#define ipcid_to_seqx(id) ((id) / SEQ_MULTIPLIER) +#define IPCID_SEQ_MAX min_t(int, INT_MAX/SEQ_MULTIPLIER, USHRT_MAX) + +/* must be called with ids->rwsem acquired for writing */ +int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int); + +/* must be called with ids->rwsem acquired for reading */ +int ipc_get_maxid(struct ipc_ids *); + +/* must be called with both locks acquired. */ +void ipc_rmid(struct ipc_ids *, struct kern_ipc_perm *); + +/* must be called with ipcp locked */ +int ipcperms(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp, short flg); + +/* for rare, potentially huge allocations. + * both function can sleep + */ +void *ipc_alloc(int size); +void ipc_free(void *ptr, int size); + +/* + * For allocation that need to be freed by RCU. + * Objects are reference counted, they start with reference count 1. + * getref increases the refcount, the putref call that reduces the recount + * to 0 schedules the rcu destruction. Caller must guarantee locking. + */ +void *ipc_rcu_alloc(int size); +int ipc_rcu_getref(void *ptr); +void ipc_rcu_putref(void *ptr, void (*func)(struct rcu_head *head)); +void ipc_rcu_free(struct rcu_head *head); + +struct kern_ipc_perm *ipc_lock(struct ipc_ids *, int); +struct kern_ipc_perm *ipc_obtain_object(struct ipc_ids *ids, int id); + +void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out); +void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out); +int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out); +struct kern_ipc_perm *ipcctl_pre_down_nolock(struct ipc_namespace *ns, + struct ipc_ids *ids, int id, int cmd, + struct ipc64_perm *perm, int extra_perm); + +#ifndef CONFIG_ARCH_WANT_IPC_PARSE_VERSION +/* On IA-64, we always use the "64-bit version" of the IPC structures. */ +# define ipc_parse_version(cmd) IPC_64 +#else +int ipc_parse_version(int *cmd); +#endif + +extern void free_msg(struct msg_msg *msg); +extern struct msg_msg *load_msg(const void __user *src, size_t len); +extern struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst); +extern int store_msg(void __user *dest, struct msg_msg *msg, size_t len); + +extern void recompute_msgmni(struct ipc_namespace *); + +static inline int ipc_buildid(int id, int seq) +{ + return SEQ_MULTIPLIER * seq + id; +} + +static inline int ipc_checkid(struct kern_ipc_perm *ipcp, int uid) +{ + return uid / SEQ_MULTIPLIER != ipcp->seq; +} + +static inline void ipc_lock_object(struct kern_ipc_perm *perm) +{ + spin_lock(&perm->lock); +} + +static inline void ipc_unlock_object(struct kern_ipc_perm *perm) +{ + spin_unlock(&perm->lock); +} + +static inline void ipc_assert_locked_object(struct kern_ipc_perm *perm) +{ + assert_spin_locked(&perm->lock); +} + +static inline void ipc_unlock(struct kern_ipc_perm *perm) +{ + ipc_unlock_object(perm); + rcu_read_unlock(); +} + +/* + * ipc_valid_object() - helper to sort out IPC_RMID races for codepaths + * where the respective ipc_ids.rwsem is not being held down. + * Checks whether the ipc object is still around or if it's gone already, as + * ipc_rmid() may have already freed the ID while the ipc lock was spinning. + * Needs to be called with kern_ipc_perm.lock held -- exception made for one + * checkpoint case at sys_semtimedop() as noted in code commentary. + */ +static inline bool ipc_valid_object(struct kern_ipc_perm *perm) +{ + return !perm->deleted; +} + +struct kern_ipc_perm *ipc_obtain_object_check(struct ipc_ids *ids, int id); +int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids, + const struct ipc_ops *ops, struct ipc_params *params); +void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids, + void (*free)(struct ipc_namespace *, struct kern_ipc_perm *)); +#endif -- cgit 1.2.3-korg