From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: "Joel Fernandes (Google)" To: linux-kernel@vger.kernel.org Cc: kernel-team@android.com, "Joel Fernandes (Google)" , dancol@google.com, minchan@google.com, Andrew Morton , gregkh@linuxfoundation.org, "J. Bruce Fields" , Jeff Layton , john.stultz@linaro.org, jreck@google.com, Khalid Aziz , linux-fsdevel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org, Mike Kravetz , Shuah Khan , tkjos@google.com Subject: [PATCH v2 2/2] selftests/memfd: Add tests for F_SEAL_FS_WRITE seal Date: Tue, 9 Oct 2018 15:20:42 -0700 Message-Id: <20181009222042.9781-2-joel@joelfernandes.org> In-Reply-To: <20181009222042.9781-1-joel@joelfernandes.org> References: <20181009222042.9781-1-joel@joelfernandes.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org List-ID: Add tests to verify sealing memfds with the F_SEAL_FS_WRITE works as expected. Cc: dancol@google.com Cc: minchan@google.com Signed-off-by: Joel Fernandes (Google) --- tools/testing/selftests/memfd/memfd_test.c | 51 +++++++++++++++++++++- 1 file changed, 50 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/memfd/memfd_test.c b/tools/testing/selftests/memfd/memfd_test.c index 10baa1652fc2..4bd2b6c87bb4 100644 --- a/tools/testing/selftests/memfd/memfd_test.c +++ b/tools/testing/selftests/memfd/memfd_test.c @@ -27,7 +27,7 @@ #define MFD_DEF_SIZE 8192 #define STACK_SIZE 65536 - +#define F_SEAL_FS_WRITE 0x0010 /* * Default is not to test hugetlbfs */ @@ -170,6 +170,24 @@ static void *mfd_assert_mmap_shared(int fd) return p; } +static void *mfd_fail_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() didn't fail as expected\n"); + abort(); + } + + return p; +} + static void *mfd_assert_mmap_private(int fd) { void *p; @@ -692,6 +710,36 @@ static void test_seal_write(void) close(fd); } +/* + * Test SEAL_WRITE + * Test whether SEAL_WRITE actually prevents modifications. + */ +static void test_seal_fs_write(void) +{ + int fd; + void *p; + + printf("%s SEAL-FS-WRITE\n", memfd_str); + + fd = mfd_assert_new("kern_memfd_seal_fs_write", + mfd_def_size, + MFD_CLOEXEC | MFD_ALLOW_SEALING); + + p = mfd_assert_mmap_shared(fd); + + /* FS_WRITE seal can be added even with existing + * writeable mappings */ + mfd_assert_has_seals(fd, 0); + mfd_assert_add_seals(fd, F_SEAL_FS_WRITE); + mfd_assert_has_seals(fd, F_SEAL_FS_WRITE); + + mfd_assert_read(fd); + mfd_fail_write(fd); + + munmap(p, mfd_def_size); + close(fd); +} + /* * Test SEAL_SHRINK * Test whether SEAL_SHRINK actually prevents shrinking @@ -945,6 +993,7 @@ int main(int argc, char **argv) test_basic(); test_seal_write(); + test_seal_fs_write(); test_seal_shrink(); test_seal_grow(); test_seal_resize(); -- 2.19.0.605.g01d371f741-goog