From: Daniel Verkamp dverkamp@chromium.org
Tests that ensure MFD_NOEXEC memfds have the appropriate mode bits and cannot be chmod-ed into being executable.
Co-developed-by: Jeff Xu jeffxu@chromium.org Signed-off-by: Jeff Xu jeffxu@chromium.org Signed-off-by: Daniel Verkamp dverkamp@chromium.org --- tools/testing/selftests/memfd/memfd_test.c | 34 ++++++++++++++++++++++ 1 file changed, 34 insertions(+)
diff --git a/tools/testing/selftests/memfd/memfd_test.c b/tools/testing/selftests/memfd/memfd_test.c index 1d7e7b36bbdd..4906f778564e 100644 --- a/tools/testing/selftests/memfd/memfd_test.c +++ b/tools/testing/selftests/memfd/memfd_test.c @@ -36,6 +36,10 @@ #define MAX_PATH 256 #endif
+#ifndef MFD_NOEXEC +#define MFD_NOEXEC 0x0008U +#endif + /* * Default is not to test hugetlbfs */ @@ -1006,6 +1010,35 @@ static void test_seal_exec(void) close(fd); }
+/* + * Test memfd_create with MFD_NOEXEC flag + * Test that MFD_NOEXEC applies F_SEAL_EXEC and prevents change of exec bits + */ +static void test_noexec(void) +{ + int fd; + + printf("%s NOEXEC\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); + 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); + mfd_assert_mode(fd, 0666); + mfd_assert_has_seals(fd, F_SEAL_EXEC | F_SEAL_SEAL); + mfd_fail_chmod(fd, 0777); + close(fd); +} + /* * Test sharing via dup() * Test that seals are shared between dupped FDs and they're all equal. @@ -1179,6 +1212,7 @@ int main(int argc, char **argv)
test_create(); test_basic(); + test_noexec();
test_seal_write(); test_seal_future_write();