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Diffstat (limited to 'tools/testing/selftests/memfd/memfd_test.c')
-rw-r--r--tools/testing/selftests/memfd/memfd_test.c551
1 files changed, 543 insertions, 8 deletions
diff --git a/tools/testing/selftests/memfd/memfd_test.c b/tools/testing/selftests/memfd/memfd_test.c
index 334a7eea2004..18f585684e20 100644
--- a/tools/testing/selftests/memfd/memfd_test.c
+++ b/tools/testing/selftests/memfd/memfd_test.c
@@ -6,7 +6,7 @@
#include <inttypes.h>
#include <limits.h>
#include <linux/falloc.h>
-#include <linux/fcntl.h>
+#include <fcntl.h>
#include <linux/memfd.h>
#include <sched.h>
#include <stdio.h>
@@ -18,6 +18,7 @@
#include <sys/syscall.h>
#include <sys/wait.h>
#include <unistd.h>
+#include <ctype.h>
#include "common.h"
@@ -28,12 +29,46 @@
#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;
@@ -54,9 +89,67 @@ 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: %m\n");
+ abort();
+ }
+
+ if (write(fd, val, strlen(val)) < 0) {
+ printf("write sysctl %s failed: %m\n", val);
+ 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: %m\n");
+ abort();
+ }
+
+ if (write(fd, val, strlen(val)) >= 0) {
+ printf("write sysctl %s succeeded, but failure expected\n",
+ val);
+ abort();
+ }
+}
+
+static void sysctl_assert_equal(const char *val)
+{
+ char *p, buf[128] = {};
+ int fd = open("/proc/sys/vm/memfd_noexec", O_RDONLY | O_CLOEXEC);
+
+ if (fd < 0) {
+ printf("open sysctl failed: %m\n");
+ abort();
+ }
+
+ if (read(fd, buf, sizeof(buf)) < 0) {
+ printf("read sysctl failed: %m\n");
+ abort();
+ }
+
+ /* Strip trailing whitespace. */
+ p = buf;
+ while (!isspace(*p))
+ p++;
+ *p = '\0';
+
+ if (strcmp(buf, val) != 0) {
+ printf("unexpected sysctl value: expected %s, got %s\n", val, buf);
+ abort();
+ }
+}
+
static int mfd_assert_reopen_fd(int fd_in)
{
- int r, fd;
+ int fd;
char path[100];
sprintf(path, "/proc/self/fd/%d", fd_in);
@@ -98,11 +191,13 @@ static unsigned int mfd_assert_get_seals(int fd)
static void mfd_assert_has_seals(int fd, unsigned int seals)
{
+ char buf[PATH_MAX];
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();
}
}
@@ -455,6 +550,7 @@ static void mfd_fail_write(int fd)
printf("mmap()+mprotect() didn't fail as expected\n");
abort();
}
+ munmap(p, mfd_def_size);
}
/* verify PUNCH_HOLE fails */
@@ -593,6 +689,61 @@ static void mfd_fail_grow_write(int fd)
}
}
+static void mfd_assert_mode(int fd, int mode)
+{
+ struct stat st;
+ char buf[PATH_MAX];
+
+ 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];
+
+ 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];
+
+ 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;
@@ -606,7 +757,7 @@ static int idle_thread_fn(void *arg)
return 0;
}
-static pid_t spawn_idle_thread(unsigned int flags)
+static pid_t spawn_thread(unsigned int flags, int (*fn)(void *), void *arg)
{
uint8_t *stack;
pid_t pid;
@@ -617,10 +768,7 @@ static pid_t spawn_idle_thread(unsigned int flags)
abort();
}
- pid = clone(idle_thread_fn,
- stack + STACK_SIZE,
- SIGCHLD | flags,
- NULL);
+ pid = clone(fn, stack + STACK_SIZE, SIGCHLD | flags, arg);
if (pid < 0) {
printf("clone() failed: %m\n");
abort();
@@ -629,6 +777,33 @@ static pid_t spawn_idle_thread(unsigned int flags)
return pid;
}
+static void join_thread(pid_t pid)
+{
+ int wstatus;
+
+ if (waitpid(pid, &wstatus, 0) < 0) {
+ printf("newpid thread: waitpid() failed: %m\n");
+ abort();
+ }
+
+ if (WIFEXITED(wstatus) && WEXITSTATUS(wstatus) != 0) {
+ printf("newpid thread: exited with non-zero error code %d\n",
+ WEXITSTATUS(wstatus));
+ abort();
+ }
+
+ if (WIFSIGNALED(wstatus)) {
+ printf("newpid thread: killed by signal %d\n",
+ WTERMSIG(wstatus));
+ abort();
+ }
+}
+
+static pid_t spawn_idle_thread(unsigned int flags)
+{
+ return spawn_thread(flags, idle_thread_fn, NULL);
+}
+
static void join_idle_thread(pid_t pid)
{
kill(pid, SIGTERM);
@@ -670,6 +845,9 @@ 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);
@@ -880,6 +1058,357 @@ 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_sysctl0(void)
+{
+ int fd;
+
+ sysctl_assert_equal("0");
+
+ fd = mfd_assert_new("kern_memfd_sysctl_0_dfl",
+ 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);
+}
+
+static void test_sysctl_set_sysctl0(void)
+{
+ sysctl_assert_write("0");
+ test_sysctl_sysctl0();
+}
+
+static void test_sysctl_sysctl1(void)
+{
+ int fd;
+
+ sysctl_assert_equal("1");
+
+ fd = mfd_assert_new("kern_memfd_sysctl_1_dfl",
+ 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);
+
+ fd = mfd_assert_new("kern_memfd_sysctl_1_exec",
+ mfd_def_size,
+ MFD_CLOEXEC | MFD_EXEC | MFD_ALLOW_SEALING);
+ mfd_assert_mode(fd, 0777);
+ mfd_assert_has_seals(fd, 0);
+ mfd_assert_chmod(fd, 0644);
+ close(fd);
+
+ fd = mfd_assert_new("kern_memfd_sysctl_1_noexec",
+ mfd_def_size,
+ MFD_CLOEXEC | MFD_NOEXEC_SEAL | MFD_ALLOW_SEALING);
+ mfd_assert_mode(fd, 0666);
+ mfd_assert_has_seals(fd, F_SEAL_EXEC);
+ mfd_fail_chmod(fd, 0777);
+ close(fd);
+}
+
+static void test_sysctl_set_sysctl1(void)
+{
+ sysctl_assert_write("1");
+ test_sysctl_sysctl1();
+}
+
+static void test_sysctl_sysctl2(void)
+{
+ int fd;
+
+ sysctl_assert_equal("2");
+
+ fd = mfd_assert_new("kern_memfd_sysctl_2_dfl",
+ 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);
+
+ mfd_fail_new("kern_memfd_sysctl_2_exec",
+ MFD_CLOEXEC | MFD_EXEC | MFD_ALLOW_SEALING);
+
+ fd = mfd_assert_new("kern_memfd_sysctl_2_noexec",
+ mfd_def_size,
+ MFD_CLOEXEC | MFD_NOEXEC_SEAL | MFD_ALLOW_SEALING);
+ mfd_assert_mode(fd, 0666);
+ mfd_assert_has_seals(fd, F_SEAL_EXEC);
+ mfd_fail_chmod(fd, 0777);
+ close(fd);
+}
+
+static void test_sysctl_set_sysctl2(void)
+{
+ sysctl_assert_write("2");
+ test_sysctl_sysctl2();
+}
+
+static int sysctl_simple_child(void *arg)
+{
+ printf("%s sysctl 0\n", memfd_str);
+ test_sysctl_set_sysctl0();
+
+ printf("%s sysctl 1\n", memfd_str);
+ test_sysctl_set_sysctl1();
+
+ printf("%s sysctl 0\n", memfd_str);
+ test_sysctl_set_sysctl0();
+
+ printf("%s sysctl 2\n", memfd_str);
+ test_sysctl_set_sysctl2();
+
+ printf("%s sysctl 1\n", memfd_str);
+ test_sysctl_set_sysctl1();
+
+ printf("%s sysctl 0\n", memfd_str);
+ test_sysctl_set_sysctl0();
+
+ return 0;
+}
+
+/*
+ * Test sysctl
+ * A very basic test to make sure the core sysctl semantics work.
+ */
+static void test_sysctl_simple(void)
+{
+ int pid = spawn_thread(CLONE_NEWPID, sysctl_simple_child, NULL);
+
+ join_thread(pid);
+}
+
+static int sysctl_nested(void *arg)
+{
+ void (*fn)(void) = arg;
+
+ fn();
+ return 0;
+}
+
+static int sysctl_nested_wait(void *arg)
+{
+ /* Wait for a SIGCONT. */
+ kill(getpid(), SIGSTOP);
+ return sysctl_nested(arg);
+}
+
+static void test_sysctl_sysctl1_failset(void)
+{
+ sysctl_fail_write("0");
+ test_sysctl_sysctl1();
+}
+
+static void test_sysctl_sysctl2_failset(void)
+{
+ sysctl_fail_write("1");
+ test_sysctl_sysctl2();
+
+ sysctl_fail_write("0");
+ test_sysctl_sysctl2();
+}
+
+static int sysctl_nested_child(void *arg)
+{
+ int pid;
+
+ printf("%s nested sysctl 0\n", memfd_str);
+ sysctl_assert_write("0");
+ /* A further nested pidns works the same. */
+ pid = spawn_thread(CLONE_NEWPID, sysctl_simple_child, NULL);
+ join_thread(pid);
+
+ printf("%s nested sysctl 1\n", memfd_str);
+ sysctl_assert_write("1");
+ /* Child inherits our setting. */
+ pid = spawn_thread(CLONE_NEWPID, sysctl_nested, test_sysctl_sysctl1);
+ join_thread(pid);
+ /* Child cannot raise the setting. */
+ pid = spawn_thread(CLONE_NEWPID, sysctl_nested,
+ test_sysctl_sysctl1_failset);
+ join_thread(pid);
+ /* Child can lower the setting. */
+ pid = spawn_thread(CLONE_NEWPID, sysctl_nested,
+ test_sysctl_set_sysctl2);
+ join_thread(pid);
+ /* Child lowering the setting has no effect on our setting. */
+ test_sysctl_sysctl1();
+
+ printf("%s nested sysctl 2\n", memfd_str);
+ sysctl_assert_write("2");
+ /* Child inherits our setting. */
+ pid = spawn_thread(CLONE_NEWPID, sysctl_nested, test_sysctl_sysctl2);
+ join_thread(pid);
+ /* Child cannot raise the setting. */
+ pid = spawn_thread(CLONE_NEWPID, sysctl_nested,
+ test_sysctl_sysctl2_failset);
+ join_thread(pid);
+
+ /* Verify that the rules are actually inherited after fork. */
+ printf("%s nested sysctl 0 -> 1 after fork\n", memfd_str);
+ sysctl_assert_write("0");
+
+ pid = spawn_thread(CLONE_NEWPID, sysctl_nested_wait,
+ test_sysctl_sysctl1_failset);
+ sysctl_assert_write("1");
+ kill(pid, SIGCONT);
+ join_thread(pid);
+
+ printf("%s nested sysctl 0 -> 2 after fork\n", memfd_str);
+ sysctl_assert_write("0");
+
+ pid = spawn_thread(CLONE_NEWPID, sysctl_nested_wait,
+ test_sysctl_sysctl2_failset);
+ sysctl_assert_write("2");
+ kill(pid, SIGCONT);
+ join_thread(pid);
+
+ /*
+ * Verify that the current effective setting is saved on fork, meaning
+ * that the parent lowering the sysctl doesn't affect already-forked
+ * children.
+ */
+ printf("%s nested sysctl 2 -> 1 after fork\n", memfd_str);
+ sysctl_assert_write("2");
+ pid = spawn_thread(CLONE_NEWPID, sysctl_nested_wait,
+ test_sysctl_sysctl2);
+ sysctl_assert_write("1");
+ kill(pid, SIGCONT);
+ join_thread(pid);
+
+ printf("%s nested sysctl 2 -> 0 after fork\n", memfd_str);
+ sysctl_assert_write("2");
+ pid = spawn_thread(CLONE_NEWPID, sysctl_nested_wait,
+ test_sysctl_sysctl2);
+ sysctl_assert_write("0");
+ kill(pid, SIGCONT);
+ join_thread(pid);
+
+ printf("%s nested sysctl 1 -> 0 after fork\n", memfd_str);
+ sysctl_assert_write("1");
+ pid = spawn_thread(CLONE_NEWPID, sysctl_nested_wait,
+ test_sysctl_sysctl1);
+ sysctl_assert_write("0");
+ kill(pid, SIGCONT);
+ join_thread(pid);
+
+ return 0;
+}
+
+/*
+ * Test sysctl with nested pid namespaces
+ * Make sure that the sysctl nesting semantics work correctly.
+ */
+static void test_sysctl_nested(void)
+{
+ int pid = spawn_thread(CLONE_NEWPID, sysctl_nested_child, NULL);
+
+ join_thread(pid);
+}
+
+/*
* Test sharing via dup()
* Test that seals are shared between dupped FDs and they're all equal.
*/
@@ -1052,6 +1581,9 @@ 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();
@@ -1059,6 +1591,9 @@ int main(int argc, char **argv)
test_seal_grow();
test_seal_resize();
+ test_sysctl_simple();
+ test_sysctl_nested();
+
test_share_dup("SHARE-DUP", "");
test_share_mmap("SHARE-MMAP", "");
test_share_open("SHARE-OPEN", "");
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.