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Diffstat (limited to 'tools/testing/selftests/memfd/memfd_test.c')
-rw-r--r--tools/testing/selftests/memfd/memfd_test.c341
1 files changed, 340 insertions, 1 deletions
diff --git a/tools/testing/selftests/memfd/memfd_test.c b/tools/testing/selftests/memfd/memfd_test.c
index 94df2692e6e4..ae71f15f790d 100644
--- a/tools/testing/selftests/memfd/memfd_test.c
+++ b/tools/testing/selftests/memfd/memfd_test.c
@@ -28,12 +28,46 @@
#define MFD_DEF_SIZE 8192
#define STACK_SIZE 65536
+#define F_SEAL_EXEC 0x0020
+
+#define F_WX_SEALS (F_SEAL_SHRINK | \
+ F_SEAL_GROW | \
+ F_SEAL_WRITE | \
+ F_SEAL_FUTURE_WRITE | \
+ F_SEAL_EXEC)
+
+#define MFD_NOEXEC_SEAL 0x0008U
+
/*
* Default is not to test hugetlbfs
*/
static size_t mfd_def_size = MFD_DEF_SIZE;
static const char *memfd_str = MEMFD_STR;
+static ssize_t fd2name(int fd, char *buf, size_t bufsize)
+{
+ char buf1[PATH_MAX];
+ int size;
+ ssize_t nbytes;
+
+ size = snprintf(buf1, PATH_MAX, "/proc/self/fd/%d", fd);
+ if (size < 0) {
+ printf("snprintf(%d) failed on %m\n", fd);
+ abort();
+ }
+
+ /*
+ * reserver one byte for string termination.
+ */
+ nbytes = readlink(buf1, buf, bufsize-1);
+ if (nbytes == -1) {
+ printf("readlink(%s) failed %m\n", buf1);
+ abort();
+ }
+ buf[nbytes] = '\0';
+ return nbytes;
+}
+
static int mfd_assert_new(const char *name, loff_t sz, unsigned int flags)
{
int r, fd;
@@ -54,6 +88,37 @@ static int mfd_assert_new(const char *name, loff_t sz, unsigned int flags)
return fd;
}
+static void sysctl_assert_write(const char *val)
+{
+ int fd = open("/proc/sys/vm/memfd_noexec", O_WRONLY | O_CLOEXEC);
+
+ if (fd < 0) {
+ printf("open sysctl failed\n");
+ abort();
+ }
+
+ if (write(fd, val, strlen(val)) < 0) {
+ printf("write sysctl failed\n");
+ abort();
+ }
+}
+
+static void sysctl_fail_write(const char *val)
+{
+ int fd = open("/proc/sys/vm/memfd_noexec", O_WRONLY | O_CLOEXEC);
+
+ if (fd < 0) {
+ printf("open sysctl failed\n");
+ abort();
+ }
+
+ if (write(fd, val, strlen(val)) >= 0) {
+ printf("write sysctl %s succeeded, but failure expected\n",
+ val);
+ abort();
+ }
+}
+
static int mfd_assert_reopen_fd(int fd_in)
{
int fd;
@@ -98,11 +163,14 @@ static unsigned int mfd_assert_get_seals(int fd)
static void mfd_assert_has_seals(int fd, unsigned int seals)
{
+ char buf[PATH_MAX];
+ int nbytes;
unsigned int s;
+ fd2name(fd, buf, PATH_MAX);
s = mfd_assert_get_seals(fd);
if (s != seals) {
- printf("%u != %u = GET_SEALS(%d)\n", seals, s, fd);
+ printf("%u != %u = GET_SEALS(%s)\n", seals, s, buf);
abort();
}
}
@@ -594,6 +662,64 @@ static void mfd_fail_grow_write(int fd)
}
}
+static void mfd_assert_mode(int fd, int mode)
+{
+ struct stat st;
+ char buf[PATH_MAX];
+ int nbytes;
+
+ fd2name(fd, buf, PATH_MAX);
+
+ if (fstat(fd, &st) < 0) {
+ printf("fstat(%s) failed: %m\n", buf);
+ abort();
+ }
+
+ if ((st.st_mode & 07777) != mode) {
+ printf("fstat(%s) wrong file mode 0%04o, but expected 0%04o\n",
+ buf, (int)st.st_mode & 07777, mode);
+ abort();
+ }
+}
+
+static void mfd_assert_chmod(int fd, int mode)
+{
+ char buf[PATH_MAX];
+ int nbytes;
+
+ fd2name(fd, buf, PATH_MAX);
+
+ if (fchmod(fd, mode) < 0) {
+ printf("fchmod(%s, 0%04o) failed: %m\n", buf, mode);
+ abort();
+ }
+
+ mfd_assert_mode(fd, mode);
+}
+
+static void mfd_fail_chmod(int fd, int mode)
+{
+ struct stat st;
+ char buf[PATH_MAX];
+ int nbytes;
+
+ fd2name(fd, buf, PATH_MAX);
+
+ if (fstat(fd, &st) < 0) {
+ printf("fstat(%s) failed: %m\n", buf);
+ abort();
+ }
+
+ if (fchmod(fd, mode) == 0) {
+ printf("fchmod(%s, 0%04o) didn't fail as expected\n",
+ buf, mode);
+ abort();
+ }
+
+ /* verify that file mode bits did not change */
+ mfd_assert_mode(fd, st.st_mode & 07777);
+}
+
static int idle_thread_fn(void *arg)
{
sigset_t set;
@@ -671,6 +797,9 @@ static void test_create(void)
mfd_fail_new("", ~0);
mfd_fail_new("", 0x80000000U);
+ /* verify EXEC and NOEXEC_SEAL can't both be set */
+ mfd_fail_new("", MFD_EXEC | MFD_NOEXEC_SEAL);
+
/* verify MFD_CLOEXEC is allowed */
fd = mfd_assert_new("", 0, MFD_CLOEXEC);
close(fd);
@@ -881,6 +1010,211 @@ static void test_seal_resize(void)
}
/*
+ * Test SEAL_EXEC
+ * Test fd is created with exec and allow sealing.
+ * chmod() cannot change x bits after sealing.
+ */
+static void test_exec_seal(void)
+{
+ int fd;
+
+ printf("%s SEAL-EXEC\n", memfd_str);
+
+ printf("%s Apply SEAL_EXEC\n", memfd_str);
+ fd = mfd_assert_new("kern_memfd_seal_exec",
+ mfd_def_size,
+ MFD_CLOEXEC | MFD_ALLOW_SEALING | MFD_EXEC);
+
+ mfd_assert_mode(fd, 0777);
+ mfd_assert_chmod(fd, 0644);
+
+ mfd_assert_has_seals(fd, 0);
+ mfd_assert_add_seals(fd, F_SEAL_EXEC);
+ mfd_assert_has_seals(fd, F_SEAL_EXEC);
+
+ mfd_assert_chmod(fd, 0600);
+ mfd_fail_chmod(fd, 0777);
+ mfd_fail_chmod(fd, 0670);
+ mfd_fail_chmod(fd, 0605);
+ mfd_fail_chmod(fd, 0700);
+ mfd_fail_chmod(fd, 0100);
+ mfd_assert_chmod(fd, 0666);
+ mfd_assert_write(fd);
+ close(fd);
+
+ printf("%s Apply ALL_SEALS\n", memfd_str);
+ fd = mfd_assert_new("kern_memfd_seal_exec",
+ mfd_def_size,
+ MFD_CLOEXEC | MFD_ALLOW_SEALING | MFD_EXEC);
+
+ mfd_assert_mode(fd, 0777);
+ mfd_assert_chmod(fd, 0700);
+
+ mfd_assert_has_seals(fd, 0);
+ mfd_assert_add_seals(fd, F_SEAL_EXEC);
+ mfd_assert_has_seals(fd, F_WX_SEALS);
+
+ mfd_fail_chmod(fd, 0711);
+ mfd_fail_chmod(fd, 0600);
+ mfd_fail_write(fd);
+ close(fd);
+}
+
+/*
+ * Test EXEC_NO_SEAL
+ * Test fd is created with exec and not allow sealing.
+ */
+static void test_exec_no_seal(void)
+{
+ int fd;
+
+ printf("%s EXEC_NO_SEAL\n", memfd_str);
+
+ /* Create with EXEC but without ALLOW_SEALING */
+ fd = mfd_assert_new("kern_memfd_exec_no_sealing",
+ mfd_def_size,
+ MFD_CLOEXEC | MFD_EXEC);
+ mfd_assert_mode(fd, 0777);
+ mfd_assert_has_seals(fd, F_SEAL_SEAL);
+ mfd_assert_chmod(fd, 0666);
+ close(fd);
+}
+
+/*
+ * Test memfd_create with MFD_NOEXEC flag
+ */
+static void test_noexec_seal(void)
+{
+ int fd;
+
+ printf("%s NOEXEC_SEAL\n", memfd_str);
+
+ /* Create with NOEXEC and ALLOW_SEALING */
+ fd = mfd_assert_new("kern_memfd_noexec",
+ mfd_def_size,
+ MFD_CLOEXEC | MFD_ALLOW_SEALING | MFD_NOEXEC_SEAL);
+ mfd_assert_mode(fd, 0666);
+ mfd_assert_has_seals(fd, F_SEAL_EXEC);
+ mfd_fail_chmod(fd, 0777);
+ close(fd);
+
+ /* Create with NOEXEC but without ALLOW_SEALING */
+ fd = mfd_assert_new("kern_memfd_noexec",
+ mfd_def_size,
+ MFD_CLOEXEC | MFD_NOEXEC_SEAL);
+ mfd_assert_mode(fd, 0666);
+ mfd_assert_has_seals(fd, F_SEAL_EXEC);
+ mfd_fail_chmod(fd, 0777);
+ close(fd);
+}
+
+static void test_sysctl_child(void)
+{
+ int fd;
+
+ printf("%s sysctl 0\n", memfd_str);
+ sysctl_assert_write("0");
+ fd = mfd_assert_new("kern_memfd_sysctl_0",
+ mfd_def_size,
+ MFD_CLOEXEC | MFD_ALLOW_SEALING);
+
+ mfd_assert_mode(fd, 0777);
+ mfd_assert_has_seals(fd, 0);
+ mfd_assert_chmod(fd, 0644);
+ close(fd);
+
+ printf("%s sysctl 1\n", memfd_str);
+ sysctl_assert_write("1");
+ fd = mfd_assert_new("kern_memfd_sysctl_1",
+ mfd_def_size,
+ MFD_CLOEXEC | MFD_ALLOW_SEALING);
+
+ mfd_assert_mode(fd, 0666);
+ mfd_assert_has_seals(fd, F_SEAL_EXEC);
+ mfd_fail_chmod(fd, 0777);
+ sysctl_fail_write("0");
+ close(fd);
+
+ printf("%s sysctl 2\n", memfd_str);
+ sysctl_assert_write("2");
+ mfd_fail_new("kern_memfd_sysctl_2",
+ MFD_CLOEXEC | MFD_ALLOW_SEALING);
+ sysctl_fail_write("0");
+ sysctl_fail_write("1");
+}
+
+static int newpid_thread_fn(void *arg)
+{
+ test_sysctl_child();
+ return 0;
+}
+
+static void test_sysctl_child2(void)
+{
+ int fd;
+
+ sysctl_fail_write("0");
+ fd = mfd_assert_new("kern_memfd_sysctl_1",
+ mfd_def_size,
+ MFD_CLOEXEC | MFD_ALLOW_SEALING);
+
+ mfd_assert_mode(fd, 0666);
+ mfd_assert_has_seals(fd, F_SEAL_EXEC);
+ mfd_fail_chmod(fd, 0777);
+ close(fd);
+}
+
+static int newpid_thread_fn2(void *arg)
+{
+ test_sysctl_child2();
+ return 0;
+}
+static pid_t spawn_newpid_thread(unsigned int flags, int (*fn)(void *))
+{
+ uint8_t *stack;
+ pid_t pid;
+
+ stack = malloc(STACK_SIZE);
+ if (!stack) {
+ printf("malloc(STACK_SIZE) failed: %m\n");
+ abort();
+ }
+
+ pid = clone(fn,
+ stack + STACK_SIZE,
+ SIGCHLD | flags,
+ NULL);
+ if (pid < 0) {
+ printf("clone() failed: %m\n");
+ abort();
+ }
+
+ return pid;
+}
+
+static void join_newpid_thread(pid_t pid)
+{
+ waitpid(pid, NULL, 0);
+}
+
+/*
+ * Test sysctl
+ * A very basic sealing test to see whether setting/retrieving seals works.
+ */
+static void test_sysctl(void)
+{
+ int pid = spawn_newpid_thread(CLONE_NEWPID, newpid_thread_fn);
+
+ join_newpid_thread(pid);
+
+ printf("%s child ns\n", memfd_str);
+ sysctl_assert_write("1");
+
+ pid = spawn_newpid_thread(CLONE_NEWPID, newpid_thread_fn2);
+ join_newpid_thread(pid);
+}
+
+/*
* Test sharing via dup()
* Test that seals are shared between dupped FDs and they're all equal.
*/
@@ -1053,6 +1387,9 @@ int main(int argc, char **argv)
test_create();
test_basic();
+ test_exec_seal();
+ test_exec_no_seal();
+ test_noexec_seal();
test_seal_write();
test_seal_future_write();
@@ -1074,6 +1411,8 @@ int main(int argc, char **argv)
test_share_fork("SHARE-FORK", SHARED_FT_STR);
join_idle_thread(pid);
+ test_sysctl();
+
printf("memfd: DONE\n");
return 0;
generated by cgit (git 2.34.1) at 2024-06-18 12:15:46 +0000