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-rw-r--r--kernel/tools/testing/selftests/memfd/.gitignore4
-rw-r--r--kernel/tools/testing/selftests/memfd/Makefile22
-rw-r--r--kernel/tools/testing/selftests/memfd/fuse_mnt.c110
-rw-r--r--kernel/tools/testing/selftests/memfd/fuse_test.c311
-rw-r--r--kernel/tools/testing/selftests/memfd/memfd_test.c911
-rw-r--r--kernel/tools/testing/selftests/memfd/run_fuse_test.sh14
6 files changed, 1372 insertions, 0 deletions
diff --git a/kernel/tools/testing/selftests/memfd/.gitignore b/kernel/tools/testing/selftests/memfd/.gitignore
new file mode 100644
index 000000000..afe87c40a
--- /dev/null
+++ b/kernel/tools/testing/selftests/memfd/.gitignore
@@ -0,0 +1,4 @@
+fuse_mnt
+fuse_test
+memfd_test
+memfd-test-file
diff --git a/kernel/tools/testing/selftests/memfd/Makefile b/kernel/tools/testing/selftests/memfd/Makefile
new file mode 100644
index 000000000..3e7eb7972
--- /dev/null
+++ b/kernel/tools/testing/selftests/memfd/Makefile
@@ -0,0 +1,22 @@
+CC = $(CROSS_COMPILE)gcc
+CFLAGS += -D_FILE_OFFSET_BITS=64
+CFLAGS += -I../../../../include/uapi/
+CFLAGS += -I../../../../include/
+CFLAGS += -I../../../../usr/include/
+
+all:
+ $(CC) $(CFLAGS) memfd_test.c -o memfd_test
+
+TEST_PROGS := memfd_test
+
+include ../lib.mk
+
+build_fuse:
+ $(CC) $(CFLAGS) fuse_mnt.c `pkg-config fuse --cflags --libs` -o fuse_mnt
+ $(CC) $(CFLAGS) fuse_test.c -o fuse_test
+
+run_fuse: build_fuse
+ @./run_fuse_test.sh || echo "fuse_test: [FAIL]"
+
+clean:
+ $(RM) memfd_test fuse_test
diff --git a/kernel/tools/testing/selftests/memfd/fuse_mnt.c b/kernel/tools/testing/selftests/memfd/fuse_mnt.c
new file mode 100644
index 000000000..feacf1280
--- /dev/null
+++ b/kernel/tools/testing/selftests/memfd/fuse_mnt.c
@@ -0,0 +1,110 @@
+/*
+ * memfd test file-system
+ * This file uses FUSE to create a dummy file-system with only one file /memfd.
+ * This file is read-only and takes 1s per read.
+ *
+ * This file-system is used by the memfd test-cases to force the kernel to pin
+ * pages during reads(). Due to the 1s delay of this file-system, this is a
+ * nice way to test race-conditions against get_user_pages() in the kernel.
+ *
+ * We use direct_io==1 to force the kernel to use direct-IO for this
+ * file-system.
+ */
+
+#define FUSE_USE_VERSION 26
+
+#include <fuse.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+static const char memfd_content[] = "memfd-example-content";
+static const char memfd_path[] = "/memfd";
+
+static int memfd_getattr(const char *path, struct stat *st)
+{
+ memset(st, 0, sizeof(*st));
+
+ if (!strcmp(path, "/")) {
+ st->st_mode = S_IFDIR | 0755;
+ st->st_nlink = 2;
+ } else if (!strcmp(path, memfd_path)) {
+ st->st_mode = S_IFREG | 0444;
+ st->st_nlink = 1;
+ st->st_size = strlen(memfd_content);
+ } else {
+ return -ENOENT;
+ }
+
+ return 0;
+}
+
+static int memfd_readdir(const char *path,
+ void *buf,
+ fuse_fill_dir_t filler,
+ off_t offset,
+ struct fuse_file_info *fi)
+{
+ if (strcmp(path, "/"))
+ return -ENOENT;
+
+ filler(buf, ".", NULL, 0);
+ filler(buf, "..", NULL, 0);
+ filler(buf, memfd_path + 1, NULL, 0);
+
+ return 0;
+}
+
+static int memfd_open(const char *path, struct fuse_file_info *fi)
+{
+ if (strcmp(path, memfd_path))
+ return -ENOENT;
+
+ if ((fi->flags & 3) != O_RDONLY)
+ return -EACCES;
+
+ /* force direct-IO */
+ fi->direct_io = 1;
+
+ return 0;
+}
+
+static int memfd_read(const char *path,
+ char *buf,
+ size_t size,
+ off_t offset,
+ struct fuse_file_info *fi)
+{
+ size_t len;
+
+ if (strcmp(path, memfd_path) != 0)
+ return -ENOENT;
+
+ sleep(1);
+
+ len = strlen(memfd_content);
+ if (offset < len) {
+ if (offset + size > len)
+ size = len - offset;
+
+ memcpy(buf, memfd_content + offset, size);
+ } else {
+ size = 0;
+ }
+
+ return size;
+}
+
+static struct fuse_operations memfd_ops = {
+ .getattr = memfd_getattr,
+ .readdir = memfd_readdir,
+ .open = memfd_open,
+ .read = memfd_read,
+};
+
+int main(int argc, char *argv[])
+{
+ return fuse_main(argc, argv, &memfd_ops, NULL);
+}
diff --git a/kernel/tools/testing/selftests/memfd/fuse_test.c b/kernel/tools/testing/selftests/memfd/fuse_test.c
new file mode 100644
index 000000000..67908b18f
--- /dev/null
+++ b/kernel/tools/testing/selftests/memfd/fuse_test.c
@@ -0,0 +1,311 @@
+/*
+ * memfd GUP test-case
+ * This tests memfd interactions with get_user_pages(). We require the
+ * fuse_mnt.c program to provide a fake direct-IO FUSE mount-point for us. This
+ * file-system delays _all_ reads by 1s and forces direct-IO. This means, any
+ * read() on files in that file-system will pin the receive-buffer pages for at
+ * least 1s via get_user_pages().
+ *
+ * We use this trick to race ADD_SEALS against a write on a memfd object. The
+ * ADD_SEALS must fail if the memfd pages are still pinned. Note that we use
+ * the read() syscall with our memory-mapped memfd object as receive buffer to
+ * force the kernel to write into our memfd object.
+ */
+
+#define _GNU_SOURCE
+#define __EXPORTED_HEADERS__
+
+#include <errno.h>
+#include <inttypes.h>
+#include <limits.h>
+#include <linux/falloc.h>
+#include <linux/fcntl.h>
+#include <linux/memfd.h>
+#include <sched.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/syscall.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#define MFD_DEF_SIZE 8192
+#define STACK_SIZE 65535
+
+static int sys_memfd_create(const char *name,
+ unsigned int flags)
+{
+ return syscall(__NR_memfd_create, name, flags);
+}
+
+static int mfd_assert_new(const char *name, loff_t sz, unsigned int flags)
+{
+ int r, fd;
+
+ fd = sys_memfd_create(name, flags);
+ if (fd < 0) {
+ printf("memfd_create(\"%s\", %u) failed: %m\n",
+ name, flags);
+ abort();
+ }
+
+ r = ftruncate(fd, sz);
+ if (r < 0) {
+ printf("ftruncate(%llu) failed: %m\n", (unsigned long long)sz);
+ abort();
+ }
+
+ return fd;
+}
+
+static __u64 mfd_assert_get_seals(int fd)
+{
+ long r;
+
+ r = fcntl(fd, F_GET_SEALS);
+ if (r < 0) {
+ printf("GET_SEALS(%d) failed: %m\n", fd);
+ abort();
+ }
+
+ return r;
+}
+
+static void mfd_assert_has_seals(int fd, __u64 seals)
+{
+ __u64 s;
+
+ s = mfd_assert_get_seals(fd);
+ if (s != seals) {
+ printf("%llu != %llu = GET_SEALS(%d)\n",
+ (unsigned long long)seals, (unsigned long long)s, fd);
+ abort();
+ }
+}
+
+static void mfd_assert_add_seals(int fd, __u64 seals)
+{
+ long r;
+ __u64 s;
+
+ s = mfd_assert_get_seals(fd);
+ r = fcntl(fd, F_ADD_SEALS, seals);
+ if (r < 0) {
+ printf("ADD_SEALS(%d, %llu -> %llu) failed: %m\n",
+ fd, (unsigned long long)s, (unsigned long long)seals);
+ abort();
+ }
+}
+
+static int mfd_busy_add_seals(int fd, __u64 seals)
+{
+ long r;
+ __u64 s;
+
+ r = fcntl(fd, F_GET_SEALS);
+ if (r < 0)
+ s = 0;
+ else
+ s = r;
+
+ r = fcntl(fd, F_ADD_SEALS, seals);
+ if (r < 0 && errno != EBUSY) {
+ printf("ADD_SEALS(%d, %llu -> %llu) didn't fail as expected with EBUSY: %m\n",
+ fd, (unsigned long long)s, (unsigned long long)seals);
+ abort();
+ }
+
+ return r;
+}
+
+static void *mfd_assert_mmap_shared(int fd)
+{
+ void *p;
+
+ p = mmap(NULL,
+ MFD_DEF_SIZE,
+ PROT_READ | PROT_WRITE,
+ MAP_SHARED,
+ fd,
+ 0);
+ if (p == MAP_FAILED) {
+ printf("mmap() failed: %m\n");
+ abort();
+ }
+
+ return p;
+}
+
+static void *mfd_assert_mmap_private(int fd)
+{
+ void *p;
+
+ p = mmap(NULL,
+ MFD_DEF_SIZE,
+ PROT_READ | PROT_WRITE,
+ MAP_PRIVATE,
+ fd,
+ 0);
+ if (p == MAP_FAILED) {
+ printf("mmap() failed: %m\n");
+ abort();
+ }
+
+ return p;
+}
+
+static int global_mfd = -1;
+static void *global_p = NULL;
+
+static int sealing_thread_fn(void *arg)
+{
+ int sig, r;
+
+ /*
+ * This thread first waits 200ms so any pending operation in the parent
+ * is correctly started. After that, it tries to seal @global_mfd as
+ * SEAL_WRITE. This _must_ fail as the parent thread has a read() into
+ * that memory mapped object still ongoing.
+ * We then wait one more second and try sealing again. This time it
+ * must succeed as there shouldn't be anyone else pinning the pages.
+ */
+
+ /* wait 200ms for FUSE-request to be active */
+ usleep(200000);
+
+ /* unmount mapping before sealing to avoid i_mmap_writable failures */
+ munmap(global_p, MFD_DEF_SIZE);
+
+ /* Try sealing the global file; expect EBUSY or success. Current
+ * kernels will never succeed, but in the future, kernels might
+ * implement page-replacements or other fancy ways to avoid racing
+ * writes. */
+ r = mfd_busy_add_seals(global_mfd, F_SEAL_WRITE);
+ if (r >= 0) {
+ printf("HURRAY! This kernel fixed GUP races!\n");
+ } else {
+ /* wait 1s more so the FUSE-request is done */
+ sleep(1);
+
+ /* try sealing the global file again */
+ mfd_assert_add_seals(global_mfd, F_SEAL_WRITE);
+ }
+
+ return 0;
+}
+
+static pid_t spawn_sealing_thread(void)
+{
+ uint8_t *stack;
+ pid_t pid;
+
+ stack = malloc(STACK_SIZE);
+ if (!stack) {
+ printf("malloc(STACK_SIZE) failed: %m\n");
+ abort();
+ }
+
+ pid = clone(sealing_thread_fn,
+ stack + STACK_SIZE,
+ SIGCHLD | CLONE_FILES | CLONE_FS | CLONE_VM,
+ NULL);
+ if (pid < 0) {
+ printf("clone() failed: %m\n");
+ abort();
+ }
+
+ return pid;
+}
+
+static void join_sealing_thread(pid_t pid)
+{
+ waitpid(pid, NULL, 0);
+}
+
+int main(int argc, char **argv)
+{
+ static const char zero[MFD_DEF_SIZE];
+ int fd, mfd, r;
+ void *p;
+ int was_sealed;
+ pid_t pid;
+
+ if (argc < 2) {
+ printf("error: please pass path to file in fuse_mnt mount-point\n");
+ abort();
+ }
+
+ /* open FUSE memfd file for GUP testing */
+ printf("opening: %s\n", argv[1]);
+ fd = open(argv[1], O_RDONLY | O_CLOEXEC);
+ if (fd < 0) {
+ printf("cannot open(\"%s\"): %m\n", argv[1]);
+ abort();
+ }
+
+ /* create new memfd-object */
+ mfd = mfd_assert_new("kern_memfd_fuse",
+ MFD_DEF_SIZE,
+ MFD_CLOEXEC | MFD_ALLOW_SEALING);
+
+ /* mmap memfd-object for writing */
+ p = mfd_assert_mmap_shared(mfd);
+
+ /* pass mfd+mapping to a separate sealing-thread which tries to seal
+ * the memfd objects with SEAL_WRITE while we write into it */
+ global_mfd = mfd;
+ global_p = p;
+ pid = spawn_sealing_thread();
+
+ /* Use read() on the FUSE file to read into our memory-mapped memfd
+ * object. This races the other thread which tries to seal the
+ * memfd-object.
+ * If @fd is on the memfd-fake-FUSE-FS, the read() is delayed by 1s.
+ * This guarantees that the receive-buffer is pinned for 1s until the
+ * data is written into it. The racing ADD_SEALS should thus fail as
+ * the pages are still pinned. */
+ r = read(fd, p, MFD_DEF_SIZE);
+ if (r < 0) {
+ printf("read() failed: %m\n");
+ abort();
+ } else if (!r) {
+ printf("unexpected EOF on read()\n");
+ abort();
+ }
+
+ was_sealed = mfd_assert_get_seals(mfd) & F_SEAL_WRITE;
+
+ /* Wait for sealing-thread to finish and verify that it
+ * successfully sealed the file after the second try. */
+ join_sealing_thread(pid);
+ mfd_assert_has_seals(mfd, F_SEAL_WRITE);
+
+ /* *IF* the memfd-object was sealed at the time our read() returned,
+ * then the kernel did a page-replacement or canceled the read() (or
+ * whatever magic it did..). In that case, the memfd object is still
+ * all zero.
+ * In case the memfd-object was *not* sealed, the read() was successfull
+ * and the memfd object must *not* be all zero.
+ * Note that in real scenarios, there might be a mixture of both, but
+ * in this test-cases, we have explicit 200ms delays which should be
+ * enough to avoid any in-flight writes. */
+
+ p = mfd_assert_mmap_private(mfd);
+ if (was_sealed && memcmp(p, zero, MFD_DEF_SIZE)) {
+ printf("memfd sealed during read() but data not discarded\n");
+ abort();
+ } else if (!was_sealed && !memcmp(p, zero, MFD_DEF_SIZE)) {
+ printf("memfd sealed after read() but data discarded\n");
+ abort();
+ }
+
+ close(mfd);
+ close(fd);
+
+ printf("fuse: DONE\n");
+
+ return 0;
+}
diff --git a/kernel/tools/testing/selftests/memfd/memfd_test.c b/kernel/tools/testing/selftests/memfd/memfd_test.c
new file mode 100644
index 000000000..0b9eafb7a
--- /dev/null
+++ b/kernel/tools/testing/selftests/memfd/memfd_test.c
@@ -0,0 +1,911 @@
+#define _GNU_SOURCE
+#define __EXPORTED_HEADERS__
+
+#include <errno.h>
+#include <inttypes.h>
+#include <limits.h>
+#include <linux/falloc.h>
+#include <linux/fcntl.h>
+#include <linux/memfd.h>
+#include <sched.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+
+#define MFD_DEF_SIZE 8192
+#define STACK_SIZE 65535
+
+static int sys_memfd_create(const char *name,
+ unsigned int flags)
+{
+ return syscall(__NR_memfd_create, name, flags);
+}
+
+static int mfd_assert_new(const char *name, loff_t sz, unsigned int flags)
+{
+ int r, fd;
+
+ fd = sys_memfd_create(name, flags);
+ if (fd < 0) {
+ printf("memfd_create(\"%s\", %u) failed: %m\n",
+ name, flags);
+ abort();
+ }
+
+ r = ftruncate(fd, sz);
+ if (r < 0) {
+ printf("ftruncate(%llu) failed: %m\n", (unsigned long long)sz);
+ abort();
+ }
+
+ return fd;
+}
+
+static void mfd_fail_new(const char *name, unsigned int flags)
+{
+ int r;
+
+ r = sys_memfd_create(name, flags);
+ if (r >= 0) {
+ printf("memfd_create(\"%s\", %u) succeeded, but failure expected\n",
+ name, flags);
+ close(r);
+ abort();
+ }
+}
+
+static unsigned int mfd_assert_get_seals(int fd)
+{
+ int r;
+
+ r = fcntl(fd, F_GET_SEALS);
+ if (r < 0) {
+ printf("GET_SEALS(%d) failed: %m\n", fd);
+ abort();
+ }
+
+ return (unsigned int)r;
+}
+
+static void mfd_assert_has_seals(int fd, unsigned int seals)
+{
+ unsigned int s;
+
+ s = mfd_assert_get_seals(fd);
+ if (s != seals) {
+ printf("%u != %u = GET_SEALS(%d)\n", seals, s, fd);
+ abort();
+ }
+}
+
+static void mfd_assert_add_seals(int fd, unsigned int seals)
+{
+ int r;
+ unsigned int s;
+
+ s = mfd_assert_get_seals(fd);
+ r = fcntl(fd, F_ADD_SEALS, seals);
+ if (r < 0) {
+ printf("ADD_SEALS(%d, %u -> %u) failed: %m\n", fd, s, seals);
+ abort();
+ }
+}
+
+static void mfd_fail_add_seals(int fd, unsigned int seals)
+{
+ int r;
+ unsigned int s;
+
+ r = fcntl(fd, F_GET_SEALS);
+ if (r < 0)
+ s = 0;
+ else
+ s = (unsigned int)r;
+
+ r = fcntl(fd, F_ADD_SEALS, seals);
+ if (r >= 0) {
+ printf("ADD_SEALS(%d, %u -> %u) didn't fail as expected\n",
+ fd, s, seals);
+ abort();
+ }
+}
+
+static void mfd_assert_size(int fd, size_t size)
+{
+ struct stat st;
+ int r;
+
+ r = fstat(fd, &st);
+ if (r < 0) {
+ printf("fstat(%d) failed: %m\n", fd);
+ abort();
+ } else if (st.st_size != size) {
+ printf("wrong file size %lld, but expected %lld\n",
+ (long long)st.st_size, (long long)size);
+ abort();
+ }
+}
+
+static int mfd_assert_dup(int fd)
+{
+ int r;
+
+ r = dup(fd);
+ if (r < 0) {
+ printf("dup(%d) failed: %m\n", fd);
+ abort();
+ }
+
+ return r;
+}
+
+static void *mfd_assert_mmap_shared(int fd)
+{
+ void *p;
+
+ p = mmap(NULL,
+ MFD_DEF_SIZE,
+ PROT_READ | PROT_WRITE,
+ MAP_SHARED,
+ fd,
+ 0);
+ if (p == MAP_FAILED) {
+ printf("mmap() failed: %m\n");
+ abort();
+ }
+
+ return p;
+}
+
+static void *mfd_assert_mmap_private(int fd)
+{
+ void *p;
+
+ p = mmap(NULL,
+ MFD_DEF_SIZE,
+ PROT_READ,
+ MAP_PRIVATE,
+ fd,
+ 0);
+ if (p == MAP_FAILED) {
+ printf("mmap() failed: %m\n");
+ abort();
+ }
+
+ return p;
+}
+
+static int mfd_assert_open(int fd, int flags, mode_t mode)
+{
+ char buf[512];
+ int r;
+
+ sprintf(buf, "/proc/self/fd/%d", fd);
+ r = open(buf, flags, mode);
+ if (r < 0) {
+ printf("open(%s) failed: %m\n", buf);
+ abort();
+ }
+
+ return r;
+}
+
+static void mfd_fail_open(int fd, int flags, mode_t mode)
+{
+ char buf[512];
+ int r;
+
+ sprintf(buf, "/proc/self/fd/%d", fd);
+ r = open(buf, flags, mode);
+ if (r >= 0) {
+ printf("open(%s) didn't fail as expected\n", buf);
+ abort();
+ }
+}
+
+static void mfd_assert_read(int fd)
+{
+ char buf[16];
+ void *p;
+ ssize_t l;
+
+ l = read(fd, buf, sizeof(buf));
+ if (l != sizeof(buf)) {
+ printf("read() failed: %m\n");
+ abort();
+ }
+
+ /* verify PROT_READ *is* allowed */
+ p = mmap(NULL,
+ MFD_DEF_SIZE,
+ PROT_READ,
+ MAP_PRIVATE,
+ fd,
+ 0);
+ if (p == MAP_FAILED) {
+ printf("mmap() failed: %m\n");
+ abort();
+ }
+ munmap(p, MFD_DEF_SIZE);
+
+ /* verify MAP_PRIVATE is *always* allowed (even writable) */
+ p = mmap(NULL,
+ MFD_DEF_SIZE,
+ PROT_READ | PROT_WRITE,
+ MAP_PRIVATE,
+ fd,
+ 0);
+ if (p == MAP_FAILED) {
+ printf("mmap() failed: %m\n");
+ abort();
+ }
+ munmap(p, MFD_DEF_SIZE);
+}
+
+static void mfd_assert_write(int fd)
+{
+ ssize_t l;
+ void *p;
+ int r;
+
+ /* verify write() succeeds */
+ l = write(fd, "\0\0\0\0", 4);
+ if (l != 4) {
+ printf("write() failed: %m\n");
+ abort();
+ }
+
+ /* verify PROT_READ | PROT_WRITE is allowed */
+ p = mmap(NULL,
+ MFD_DEF_SIZE,
+ PROT_READ | PROT_WRITE,
+ MAP_SHARED,
+ fd,
+ 0);
+ if (p == MAP_FAILED) {
+ printf("mmap() failed: %m\n");
+ abort();
+ }
+ *(char *)p = 0;
+ munmap(p, MFD_DEF_SIZE);
+
+ /* verify PROT_WRITE is allowed */
+ p = mmap(NULL,
+ MFD_DEF_SIZE,
+ PROT_WRITE,
+ MAP_SHARED,
+ fd,
+ 0);
+ if (p == MAP_FAILED) {
+ printf("mmap() failed: %m\n");
+ abort();
+ }
+ *(char *)p = 0;
+ munmap(p, MFD_DEF_SIZE);
+
+ /* verify PROT_READ with MAP_SHARED is allowed and a following
+ * mprotect(PROT_WRITE) allows writing */
+ p = mmap(NULL,
+ MFD_DEF_SIZE,
+ PROT_READ,
+ MAP_SHARED,
+ fd,
+ 0);
+ if (p == MAP_FAILED) {
+ printf("mmap() failed: %m\n");
+ abort();
+ }
+
+ r = mprotect(p, MFD_DEF_SIZE, PROT_READ | PROT_WRITE);
+ if (r < 0) {
+ printf("mprotect() failed: %m\n");
+ abort();
+ }
+
+ *(char *)p = 0;
+ munmap(p, MFD_DEF_SIZE);
+
+ /* verify PUNCH_HOLE works */
+ r = fallocate(fd,
+ FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
+ 0,
+ MFD_DEF_SIZE);
+ if (r < 0) {
+ printf("fallocate(PUNCH_HOLE) failed: %m\n");
+ abort();
+ }
+}
+
+static void mfd_fail_write(int fd)
+{
+ ssize_t l;
+ void *p;
+ int r;
+
+ /* verify write() fails */
+ l = write(fd, "data", 4);
+ if (l != -EPERM) {
+ printf("expected EPERM on write(), but got %d: %m\n", (int)l);
+ abort();
+ }
+
+ /* verify PROT_READ | PROT_WRITE is not allowed */
+ p = mmap(NULL,
+ MFD_DEF_SIZE,
+ PROT_READ | PROT_WRITE,
+ MAP_SHARED,
+ fd,
+ 0);
+ if (p != MAP_FAILED) {
+ printf("mmap() didn't fail as expected\n");
+ abort();
+ }
+
+ /* verify PROT_WRITE is not allowed */
+ p = mmap(NULL,
+ MFD_DEF_SIZE,
+ PROT_WRITE,
+ MAP_SHARED,
+ fd,
+ 0);
+ if (p != MAP_FAILED) {
+ printf("mmap() didn't fail as expected\n");
+ abort();
+ }
+
+ /* Verify PROT_READ with MAP_SHARED with a following mprotect is not
+ * allowed. Note that for r/w the kernel already prevents the mmap. */
+ p = mmap(NULL,
+ MFD_DEF_SIZE,
+ PROT_READ,
+ MAP_SHARED,
+ fd,
+ 0);
+ if (p != MAP_FAILED) {
+ r = mprotect(p, MFD_DEF_SIZE, PROT_READ | PROT_WRITE);
+ if (r >= 0) {
+ printf("mmap()+mprotect() didn't fail as expected\n");
+ abort();
+ }
+ }
+
+ /* verify PUNCH_HOLE fails */
+ r = fallocate(fd,
+ FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
+ 0,
+ MFD_DEF_SIZE);
+ if (r >= 0) {
+ printf("fallocate(PUNCH_HOLE) didn't fail as expected\n");
+ abort();
+ }
+}
+
+static void mfd_assert_shrink(int fd)
+{
+ int r, fd2;
+
+ r = ftruncate(fd, MFD_DEF_SIZE / 2);
+ if (r < 0) {
+ printf("ftruncate(SHRINK) failed: %m\n");
+ abort();
+ }
+
+ mfd_assert_size(fd, MFD_DEF_SIZE / 2);
+
+ fd2 = mfd_assert_open(fd,
+ O_RDWR | O_CREAT | O_TRUNC,
+ S_IRUSR | S_IWUSR);
+ close(fd2);
+
+ mfd_assert_size(fd, 0);
+}
+
+static void mfd_fail_shrink(int fd)
+{
+ int r;
+
+ r = ftruncate(fd, MFD_DEF_SIZE / 2);
+ if (r >= 0) {
+ printf("ftruncate(SHRINK) didn't fail as expected\n");
+ abort();
+ }
+
+ mfd_fail_open(fd,
+ O_RDWR | O_CREAT | O_TRUNC,
+ S_IRUSR | S_IWUSR);
+}
+
+static void mfd_assert_grow(int fd)
+{
+ int r;
+
+ r = ftruncate(fd, MFD_DEF_SIZE * 2);
+ if (r < 0) {
+ printf("ftruncate(GROW) failed: %m\n");
+ abort();
+ }
+
+ mfd_assert_size(fd, MFD_DEF_SIZE * 2);
+
+ r = fallocate(fd,
+ 0,
+ 0,
+ MFD_DEF_SIZE * 4);
+ if (r < 0) {
+ printf("fallocate(ALLOC) failed: %m\n");
+ abort();
+ }
+
+ mfd_assert_size(fd, MFD_DEF_SIZE * 4);
+}
+
+static void mfd_fail_grow(int fd)
+{
+ int r;
+
+ r = ftruncate(fd, MFD_DEF_SIZE * 2);
+ if (r >= 0) {
+ printf("ftruncate(GROW) didn't fail as expected\n");
+ abort();
+ }
+
+ r = fallocate(fd,
+ 0,
+ 0,
+ MFD_DEF_SIZE * 4);
+ if (r >= 0) {
+ printf("fallocate(ALLOC) didn't fail as expected\n");
+ abort();
+ }
+}
+
+static void mfd_assert_grow_write(int fd)
+{
+ static char buf[MFD_DEF_SIZE * 8];
+ ssize_t l;
+
+ l = pwrite(fd, buf, sizeof(buf), 0);
+ if (l != sizeof(buf)) {
+ printf("pwrite() failed: %m\n");
+ abort();
+ }
+
+ mfd_assert_size(fd, MFD_DEF_SIZE * 8);
+}
+
+static void mfd_fail_grow_write(int fd)
+{
+ static char buf[MFD_DEF_SIZE * 8];
+ ssize_t l;
+
+ l = pwrite(fd, buf, sizeof(buf), 0);
+ if (l == sizeof(buf)) {
+ printf("pwrite() didn't fail as expected\n");
+ abort();
+ }
+}
+
+static int idle_thread_fn(void *arg)
+{
+ sigset_t set;
+ int sig;
+
+ /* dummy waiter; SIGTERM terminates us anyway */
+ sigemptyset(&set);
+ sigaddset(&set, SIGTERM);
+ sigwait(&set, &sig);
+
+ return 0;
+}
+
+static pid_t spawn_idle_thread(unsigned int flags)
+{
+ uint8_t *stack;
+ pid_t pid;
+
+ stack = malloc(STACK_SIZE);
+ if (!stack) {
+ printf("malloc(STACK_SIZE) failed: %m\n");
+ abort();
+ }
+
+ pid = clone(idle_thread_fn,
+ stack + STACK_SIZE,
+ SIGCHLD | flags,
+ NULL);
+ if (pid < 0) {
+ printf("clone() failed: %m\n");
+ abort();
+ }
+
+ return pid;
+}
+
+static void join_idle_thread(pid_t pid)
+{
+ kill(pid, SIGTERM);
+ waitpid(pid, NULL, 0);
+}
+
+/*
+ * Test memfd_create() syscall
+ * Verify syscall-argument validation, including name checks, flag validation
+ * and more.
+ */
+static void test_create(void)
+{
+ char buf[2048];
+ int fd;
+
+ /* test NULL name */
+ mfd_fail_new(NULL, 0);
+
+ /* test over-long name (not zero-terminated) */
+ memset(buf, 0xff, sizeof(buf));
+ mfd_fail_new(buf, 0);
+
+ /* test over-long zero-terminated name */
+ memset(buf, 0xff, sizeof(buf));
+ buf[sizeof(buf) - 1] = 0;
+ mfd_fail_new(buf, 0);
+
+ /* verify "" is a valid name */
+ fd = mfd_assert_new("", 0, 0);
+ close(fd);
+
+ /* verify invalid O_* open flags */
+ mfd_fail_new("", 0x0100);
+ mfd_fail_new("", ~MFD_CLOEXEC);
+ mfd_fail_new("", ~MFD_ALLOW_SEALING);
+ mfd_fail_new("", ~0);
+ mfd_fail_new("", 0x80000000U);
+
+ /* verify MFD_CLOEXEC is allowed */
+ fd = mfd_assert_new("", 0, MFD_CLOEXEC);
+ close(fd);
+
+ /* verify MFD_ALLOW_SEALING is allowed */
+ fd = mfd_assert_new("", 0, MFD_ALLOW_SEALING);
+ close(fd);
+
+ /* verify MFD_ALLOW_SEALING | MFD_CLOEXEC is allowed */
+ fd = mfd_assert_new("", 0, MFD_ALLOW_SEALING | MFD_CLOEXEC);
+ close(fd);
+}
+
+/*
+ * Test basic sealing
+ * A very basic sealing test to see whether setting/retrieving seals works.
+ */
+static void test_basic(void)
+{
+ int fd;
+
+ fd = mfd_assert_new("kern_memfd_basic",
+ MFD_DEF_SIZE,
+ MFD_CLOEXEC | MFD_ALLOW_SEALING);
+
+ /* add basic seals */
+ mfd_assert_has_seals(fd, 0);
+ mfd_assert_add_seals(fd, F_SEAL_SHRINK |
+ F_SEAL_WRITE);
+ mfd_assert_has_seals(fd, F_SEAL_SHRINK |
+ F_SEAL_WRITE);
+
+ /* add them again */
+ mfd_assert_add_seals(fd, F_SEAL_SHRINK |
+ F_SEAL_WRITE);
+ mfd_assert_has_seals(fd, F_SEAL_SHRINK |
+ F_SEAL_WRITE);
+
+ /* add more seals and seal against sealing */
+ mfd_assert_add_seals(fd, F_SEAL_GROW | F_SEAL_SEAL);
+ mfd_assert_has_seals(fd, F_SEAL_SHRINK |
+ F_SEAL_GROW |
+ F_SEAL_WRITE |
+ F_SEAL_SEAL);
+
+ /* verify that sealing no longer works */
+ mfd_fail_add_seals(fd, F_SEAL_GROW);
+ mfd_fail_add_seals(fd, 0);
+
+ close(fd);
+
+ /* verify sealing does not work without MFD_ALLOW_SEALING */
+ fd = mfd_assert_new("kern_memfd_basic",
+ MFD_DEF_SIZE,
+ MFD_CLOEXEC);
+ mfd_assert_has_seals(fd, F_SEAL_SEAL);
+ mfd_fail_add_seals(fd, F_SEAL_SHRINK |
+ F_SEAL_GROW |
+ F_SEAL_WRITE);
+ mfd_assert_has_seals(fd, F_SEAL_SEAL);
+ close(fd);
+}
+
+/*
+ * Test SEAL_WRITE
+ * Test whether SEAL_WRITE actually prevents modifications.
+ */
+static void test_seal_write(void)
+{
+ int fd;
+
+ fd = mfd_assert_new("kern_memfd_seal_write",
+ MFD_DEF_SIZE,
+ MFD_CLOEXEC | MFD_ALLOW_SEALING);
+ mfd_assert_has_seals(fd, 0);
+ mfd_assert_add_seals(fd, F_SEAL_WRITE);
+ mfd_assert_has_seals(fd, F_SEAL_WRITE);
+
+ mfd_assert_read(fd);
+ mfd_fail_write(fd);
+ mfd_assert_shrink(fd);
+ mfd_assert_grow(fd);
+ mfd_fail_grow_write(fd);
+
+ close(fd);
+}
+
+/*
+ * Test SEAL_SHRINK
+ * Test whether SEAL_SHRINK actually prevents shrinking
+ */
+static void test_seal_shrink(void)
+{
+ int fd;
+
+ fd = mfd_assert_new("kern_memfd_seal_shrink",
+ MFD_DEF_SIZE,
+ MFD_CLOEXEC | MFD_ALLOW_SEALING);
+ mfd_assert_has_seals(fd, 0);
+ mfd_assert_add_seals(fd, F_SEAL_SHRINK);
+ mfd_assert_has_seals(fd, F_SEAL_SHRINK);
+
+ mfd_assert_read(fd);
+ mfd_assert_write(fd);
+ mfd_fail_shrink(fd);
+ mfd_assert_grow(fd);
+ mfd_assert_grow_write(fd);
+
+ close(fd);
+}
+
+/*
+ * Test SEAL_GROW
+ * Test whether SEAL_GROW actually prevents growing
+ */
+static void test_seal_grow(void)
+{
+ int fd;
+
+ fd = mfd_assert_new("kern_memfd_seal_grow",
+ MFD_DEF_SIZE,
+ MFD_CLOEXEC | MFD_ALLOW_SEALING);
+ mfd_assert_has_seals(fd, 0);
+ mfd_assert_add_seals(fd, F_SEAL_GROW);
+ mfd_assert_has_seals(fd, F_SEAL_GROW);
+
+ mfd_assert_read(fd);
+ mfd_assert_write(fd);
+ mfd_assert_shrink(fd);
+ mfd_fail_grow(fd);
+ mfd_fail_grow_write(fd);
+
+ close(fd);
+}
+
+/*
+ * Test SEAL_SHRINK | SEAL_GROW
+ * Test whether SEAL_SHRINK | SEAL_GROW actually prevents resizing
+ */
+static void test_seal_resize(void)
+{
+ int fd;
+
+ fd = mfd_assert_new("kern_memfd_seal_resize",
+ MFD_DEF_SIZE,
+ MFD_CLOEXEC | MFD_ALLOW_SEALING);
+ mfd_assert_has_seals(fd, 0);
+ mfd_assert_add_seals(fd, F_SEAL_SHRINK | F_SEAL_GROW);
+ mfd_assert_has_seals(fd, F_SEAL_SHRINK | F_SEAL_GROW);
+
+ mfd_assert_read(fd);
+ mfd_assert_write(fd);
+ mfd_fail_shrink(fd);
+ mfd_fail_grow(fd);
+ mfd_fail_grow_write(fd);
+
+ close(fd);
+}
+
+/*
+ * Test sharing via dup()
+ * Test that seals are shared between dupped FDs and they're all equal.
+ */
+static void test_share_dup(void)
+{
+ int fd, fd2;
+
+ fd = mfd_assert_new("kern_memfd_share_dup",
+ MFD_DEF_SIZE,
+ MFD_CLOEXEC | MFD_ALLOW_SEALING);
+ mfd_assert_has_seals(fd, 0);
+
+ fd2 = mfd_assert_dup(fd);
+ mfd_assert_has_seals(fd2, 0);
+
+ mfd_assert_add_seals(fd, F_SEAL_WRITE);
+ mfd_assert_has_seals(fd, F_SEAL_WRITE);
+ mfd_assert_has_seals(fd2, F_SEAL_WRITE);
+
+ mfd_assert_add_seals(fd2, F_SEAL_SHRINK);
+ mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK);
+ mfd_assert_has_seals(fd2, F_SEAL_WRITE | F_SEAL_SHRINK);
+
+ mfd_assert_add_seals(fd, F_SEAL_SEAL);
+ mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK | F_SEAL_SEAL);
+ mfd_assert_has_seals(fd2, F_SEAL_WRITE | F_SEAL_SHRINK | F_SEAL_SEAL);
+
+ mfd_fail_add_seals(fd, F_SEAL_GROW);
+ mfd_fail_add_seals(fd2, F_SEAL_GROW);
+ mfd_fail_add_seals(fd, F_SEAL_SEAL);
+ mfd_fail_add_seals(fd2, F_SEAL_SEAL);
+
+ close(fd2);
+
+ mfd_fail_add_seals(fd, F_SEAL_GROW);
+ close(fd);
+}
+
+/*
+ * Test sealing with active mmap()s
+ * Modifying seals is only allowed if no other mmap() refs exist.
+ */
+static void test_share_mmap(void)
+{
+ int fd;
+ void *p;
+
+ fd = mfd_assert_new("kern_memfd_share_mmap",
+ MFD_DEF_SIZE,
+ MFD_CLOEXEC | MFD_ALLOW_SEALING);
+ mfd_assert_has_seals(fd, 0);
+
+ /* shared/writable ref prevents sealing WRITE, but allows others */
+ p = mfd_assert_mmap_shared(fd);
+ mfd_fail_add_seals(fd, F_SEAL_WRITE);
+ mfd_assert_has_seals(fd, 0);
+ mfd_assert_add_seals(fd, F_SEAL_SHRINK);
+ mfd_assert_has_seals(fd, F_SEAL_SHRINK);
+ munmap(p, MFD_DEF_SIZE);
+
+ /* readable ref allows sealing */
+ p = mfd_assert_mmap_private(fd);
+ mfd_assert_add_seals(fd, F_SEAL_WRITE);
+ mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK);
+ munmap(p, MFD_DEF_SIZE);
+
+ close(fd);
+}
+
+/*
+ * Test sealing with open(/proc/self/fd/%d)
+ * Via /proc we can get access to a separate file-context for the same memfd.
+ * This is *not* like dup(), but like a real separate open(). Make sure the
+ * semantics are as expected and we correctly check for RDONLY / WRONLY / RDWR.
+ */
+static void test_share_open(void)
+{
+ int fd, fd2;
+
+ fd = mfd_assert_new("kern_memfd_share_open",
+ MFD_DEF_SIZE,
+ MFD_CLOEXEC | MFD_ALLOW_SEALING);
+ mfd_assert_has_seals(fd, 0);
+
+ fd2 = mfd_assert_open(fd, O_RDWR, 0);
+ mfd_assert_add_seals(fd, F_SEAL_WRITE);
+ mfd_assert_has_seals(fd, F_SEAL_WRITE);
+ mfd_assert_has_seals(fd2, F_SEAL_WRITE);
+
+ mfd_assert_add_seals(fd2, F_SEAL_SHRINK);
+ mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK);
+ mfd_assert_has_seals(fd2, F_SEAL_WRITE | F_SEAL_SHRINK);
+
+ close(fd);
+ fd = mfd_assert_open(fd2, O_RDONLY, 0);
+
+ mfd_fail_add_seals(fd, F_SEAL_SEAL);
+ mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK);
+ mfd_assert_has_seals(fd2, F_SEAL_WRITE | F_SEAL_SHRINK);
+
+ close(fd2);
+ fd2 = mfd_assert_open(fd, O_RDWR, 0);
+
+ mfd_assert_add_seals(fd2, F_SEAL_SEAL);
+ mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK | F_SEAL_SEAL);
+ mfd_assert_has_seals(fd2, F_SEAL_WRITE | F_SEAL_SHRINK | F_SEAL_SEAL);
+
+ close(fd2);
+ close(fd);
+}
+
+/*
+ * Test sharing via fork()
+ * Test whether seal-modifications work as expected with forked childs.
+ */
+static void test_share_fork(void)
+{
+ int fd;
+ pid_t pid;
+
+ fd = mfd_assert_new("kern_memfd_share_fork",
+ MFD_DEF_SIZE,
+ MFD_CLOEXEC | MFD_ALLOW_SEALING);
+ mfd_assert_has_seals(fd, 0);
+
+ pid = spawn_idle_thread(0);
+ mfd_assert_add_seals(fd, F_SEAL_SEAL);
+ mfd_assert_has_seals(fd, F_SEAL_SEAL);
+
+ mfd_fail_add_seals(fd, F_SEAL_WRITE);
+ mfd_assert_has_seals(fd, F_SEAL_SEAL);
+
+ join_idle_thread(pid);
+
+ mfd_fail_add_seals(fd, F_SEAL_WRITE);
+ mfd_assert_has_seals(fd, F_SEAL_SEAL);
+
+ close(fd);
+}
+
+int main(int argc, char **argv)
+{
+ pid_t pid;
+
+ printf("memfd: CREATE\n");
+ test_create();
+ printf("memfd: BASIC\n");
+ test_basic();
+
+ printf("memfd: SEAL-WRITE\n");
+ test_seal_write();
+ printf("memfd: SEAL-SHRINK\n");
+ test_seal_shrink();
+ printf("memfd: SEAL-GROW\n");
+ test_seal_grow();
+ printf("memfd: SEAL-RESIZE\n");
+ test_seal_resize();
+
+ printf("memfd: SHARE-DUP\n");
+ test_share_dup();
+ printf("memfd: SHARE-MMAP\n");
+ test_share_mmap();
+ printf("memfd: SHARE-OPEN\n");
+ test_share_open();
+ printf("memfd: SHARE-FORK\n");
+ test_share_fork();
+
+ /* Run test-suite in a multi-threaded environment with a shared
+ * file-table. */
+ pid = spawn_idle_thread(CLONE_FILES | CLONE_FS | CLONE_VM);
+ printf("memfd: SHARE-DUP (shared file-table)\n");
+ test_share_dup();
+ printf("memfd: SHARE-MMAP (shared file-table)\n");
+ test_share_mmap();
+ printf("memfd: SHARE-OPEN (shared file-table)\n");
+ test_share_open();
+ printf("memfd: SHARE-FORK (shared file-table)\n");
+ test_share_fork();
+ join_idle_thread(pid);
+
+ printf("memfd: DONE\n");
+
+ return 0;
+}
diff --git a/kernel/tools/testing/selftests/memfd/run_fuse_test.sh b/kernel/tools/testing/selftests/memfd/run_fuse_test.sh
new file mode 100644
index 000000000..69b930e1e
--- /dev/null
+++ b/kernel/tools/testing/selftests/memfd/run_fuse_test.sh
@@ -0,0 +1,14 @@
+#!/bin/sh
+
+if test -d "./mnt" ; then
+ fusermount -u ./mnt
+ rmdir ./mnt
+fi
+
+set -e
+
+mkdir mnt
+./fuse_mnt ./mnt
+./fuse_test ./mnt/memfd
+fusermount -u ./mnt
+rmdir ./mnt