diff options
Diffstat (limited to 'kernel/security/integrity/iint.c')
| -rw-r--r-- | kernel/security/integrity/iint.c | 254 |
1 files changed, 254 insertions, 0 deletions
diff --git a/kernel/security/integrity/iint.c b/kernel/security/integrity/iint.c new file mode 100644 index 000000000..dbb6d141c --- /dev/null +++ b/kernel/security/integrity/iint.c @@ -0,0 +1,254 @@ +/* + * Copyright (C) 2008 IBM Corporation + * + * Authors: + * Mimi Zohar <zohar@us.ibm.com> + * + * 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. + * + * File: integrity_iint.c + * - implements the integrity hooks: integrity_inode_alloc, + * integrity_inode_free + * - cache integrity information associated with an inode + * using a rbtree tree. + */ +#include <linux/slab.h> +#include <linux/module.h> +#include <linux/spinlock.h> +#include <linux/rbtree.h> +#include <linux/file.h> +#include <linux/uaccess.h> +#include "integrity.h" + +static struct rb_root integrity_iint_tree = RB_ROOT; +static DEFINE_RWLOCK(integrity_iint_lock); +static struct kmem_cache *iint_cache __read_mostly; + +/* + * __integrity_iint_find - return the iint associated with an inode + */ +static struct integrity_iint_cache *__integrity_iint_find(struct inode *inode) +{ + struct integrity_iint_cache *iint; + struct rb_node *n = integrity_iint_tree.rb_node; + + while (n) { + iint = rb_entry(n, struct integrity_iint_cache, rb_node); + + if (inode < iint->inode) + n = n->rb_left; + else if (inode > iint->inode) + n = n->rb_right; + else + break; + } + if (!n) + return NULL; + + return iint; +} + +/* + * integrity_iint_find - return the iint associated with an inode + */ +struct integrity_iint_cache *integrity_iint_find(struct inode *inode) +{ + struct integrity_iint_cache *iint; + + if (!IS_IMA(inode)) + return NULL; + + read_lock(&integrity_iint_lock); + iint = __integrity_iint_find(inode); + read_unlock(&integrity_iint_lock); + + return iint; +} + +static void iint_free(struct integrity_iint_cache *iint) +{ + kfree(iint->ima_hash); + iint->ima_hash = NULL; + iint->version = 0; + iint->flags = 0UL; + iint->ima_file_status = INTEGRITY_UNKNOWN; + iint->ima_mmap_status = INTEGRITY_UNKNOWN; + iint->ima_bprm_status = INTEGRITY_UNKNOWN; + iint->ima_module_status = INTEGRITY_UNKNOWN; + iint->evm_status = INTEGRITY_UNKNOWN; + kmem_cache_free(iint_cache, iint); +} + +/** + * integrity_inode_get - find or allocate an iint associated with an inode + * @inode: pointer to the inode + * @return: allocated iint + * + * Caller must lock i_mutex + */ +struct integrity_iint_cache *integrity_inode_get(struct inode *inode) +{ + struct rb_node **p; + struct rb_node *node, *parent = NULL; + struct integrity_iint_cache *iint, *test_iint; + + iint = integrity_iint_find(inode); + if (iint) + return iint; + + iint = kmem_cache_alloc(iint_cache, GFP_NOFS); + if (!iint) + return NULL; + + write_lock(&integrity_iint_lock); + + p = &integrity_iint_tree.rb_node; + while (*p) { + parent = *p; + test_iint = rb_entry(parent, struct integrity_iint_cache, + rb_node); + if (inode < test_iint->inode) + p = &(*p)->rb_left; + else + p = &(*p)->rb_right; + } + + iint->inode = inode; + node = &iint->rb_node; + inode->i_flags |= S_IMA; + rb_link_node(node, parent, p); + rb_insert_color(node, &integrity_iint_tree); + + write_unlock(&integrity_iint_lock); + return iint; +} + +/** + * integrity_inode_free - called on security_inode_free + * @inode: pointer to the inode + * + * Free the integrity information(iint) associated with an inode. + */ +void integrity_inode_free(struct inode *inode) +{ + struct integrity_iint_cache *iint; + + if (!IS_IMA(inode)) + return; + + write_lock(&integrity_iint_lock); + iint = __integrity_iint_find(inode); + rb_erase(&iint->rb_node, &integrity_iint_tree); + write_unlock(&integrity_iint_lock); + + iint_free(iint); +} + +static void init_once(void *foo) +{ + struct integrity_iint_cache *iint = foo; + + memset(iint, 0, sizeof(*iint)); + iint->version = 0; + iint->flags = 0UL; + iint->ima_file_status = INTEGRITY_UNKNOWN; + iint->ima_mmap_status = INTEGRITY_UNKNOWN; + iint->ima_bprm_status = INTEGRITY_UNKNOWN; + iint->ima_module_status = INTEGRITY_UNKNOWN; + iint->evm_status = INTEGRITY_UNKNOWN; +} + +static int __init integrity_iintcache_init(void) +{ + iint_cache = + kmem_cache_create("iint_cache", sizeof(struct integrity_iint_cache), + 0, SLAB_PANIC, init_once); + return 0; +} +security_initcall(integrity_iintcache_init); + + +/* + * integrity_kernel_read - read data from the file + * + * This is a function for reading file content instead of kernel_read(). + * It does not perform locking checks to ensure it cannot be blocked. + * It does not perform security checks because it is irrelevant for IMA. + * + */ +int integrity_kernel_read(struct file *file, loff_t offset, + char *addr, unsigned long count) +{ + mm_segment_t old_fs; + char __user *buf = (char __user *)addr; + ssize_t ret; + + if (!(file->f_mode & FMODE_READ)) + return -EBADF; + + old_fs = get_fs(); + set_fs(get_ds()); + ret = __vfs_read(file, buf, count, &offset); + set_fs(old_fs); + + return ret; +} + +/* + * integrity_read_file - read entire file content into the buffer + * + * This is function opens a file, allocates the buffer of required + * size, read entire file content to the buffer and closes the file + * + * It is used only by init code. + * + */ +int __init integrity_read_file(const char *path, char **data) +{ + struct file *file; + loff_t size; + char *buf; + int rc = -EINVAL; + + file = filp_open(path, O_RDONLY, 0); + if (IS_ERR(file)) { + rc = PTR_ERR(file); + pr_err("Unable to open file: %s (%d)", path, rc); + return rc; + } + + size = i_size_read(file_inode(file)); + if (size <= 0) + goto out; + + buf = kmalloc(size, GFP_KERNEL); + if (!buf) { + rc = -ENOMEM; + goto out; + } + + rc = integrity_kernel_read(file, 0, buf, size); + if (rc < 0) + kfree(buf); + else if (rc != size) + rc = -EIO; + else + *data = buf; +out: + fput(file); + return rc; +} + +/* + * integrity_load_keys - load integrity keys hook + * + * Hooks is called from init/main.c:kernel_init_freeable() + * when rootfs is ready + */ +void __init integrity_load_keys(void) +{ + ima_load_x509(); +} |