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selftests/memfd: add tests for MFD_NOEXEC_SEAL MFD_EXEC

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Tests to verify MFD_NOEXEC, MFD_EXEC and vm.memfd_noexec sysctl.

Link: https://lkml.kernel.org/r/20221215001205.51969-6-jeffxu@google.com
Signed-off-by: Jeff Xu <jeffxu@google.com>
Co-developed-by: Daniel Verkamp <dverkamp@chromium.org>
Signed-off-by: Daniel Verkamp <dverkamp@chromium.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: David Herrmann <dh.herrmann@gmail.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Jorge Lucangeli Obes <jorgelo@chromium.org>
Cc: kernel test robot <lkp@intel.com>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Jeff Xu 2022-12-15 00:12:05 +00:00 committed by Andrew Morton
parent c4f75bc8bd
commit 11f75a0144
2 changed files with 225 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
tools/testing/selftests/memfd/fuse_test.c
View File

@ -22,6 +22,7 @@
#include <linux/falloc.h>
#include <fcntl.h>
#include <linux/memfd.h>
#include <linux/types.h>
#include <sched.h>
#include <stdio.h>
#include <stdlib.h>

230
tools/testing/selftests/memfd/memfd_test.c
View File

@ -30,6 +30,14 @@
#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
*/
@ -80,6 +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;
@ -758,6 +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);
@ -969,20 +1011,21 @@ static void test_seal_resize(void)
/*
* Test SEAL_EXEC
* Test that chmod() cannot change x bits after sealing
* Test fd is created with exec and allow sealing.
* chmod() cannot change x bits after sealing.
*/
static void test_seal_exec(void)
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_CLOEXEC | MFD_ALLOW_SEALING | MFD_EXEC);
mfd_assert_mode(fd, 0777);
mfd_assert_chmod(fd, 0644);
mfd_assert_has_seals(fd, 0);
@ -996,8 +1039,179 @@ static void test_seal_exec(void)
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);
}
/*
@ -1173,13 +1387,15 @@ 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();
test_seal_shrink();
test_seal_grow();
test_seal_resize();
test_seal_exec();
test_share_dup("SHARE-DUP", "");
test_share_mmap("SHARE-MMAP", "");
@ -1195,6 +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;