On Wed, Oct 17, 2018 at 11:59 PM, Joel Fernandes (Google) joel@joelfernandes.org wrote:
Add tests to verify sealing memfds with the F_SEAL_FS_WRITE works as expected.
I messed the commit message it should be "F_SEAL_FUTURE_WRITE", but otherwise this patch itself is good and I'll resend it with the corrected commit message after further review.
thanks,
- Joel
Cc: dancol@google.com Cc: minchan@kernel.org Reviewed-by: John Stultz john.stultz@linaro.org Signed-off-by: Joel Fernandes (Google) joel@joelfernandes.org
tools/testing/selftests/memfd/memfd_test.c | 74 ++++++++++++++++++++++ 1 file changed, 74 insertions(+)
diff --git a/tools/testing/selftests/memfd/memfd_test.c b/tools/testing/selftests/memfd/memfd_test.c index 10baa1652fc2..32b207ca7372 100644 --- a/tools/testing/selftests/memfd/memfd_test.c +++ b/tools/testing/selftests/memfd/memfd_test.c @@ -692,6 +692,79 @@ static void test_seal_write(void) close(fd); }
+/*
- Test SEAL_FUTURE_WRITE
- Test whether SEAL_FUTURE_WRITE actually prevents modifications.
- */
+static void test_seal_future_write(void) +{
int fd;void *p;printf("%s SEAL-FUTURE-WRITE\n", memfd_str);fd = mfd_assert_new("kern_memfd_seal_future_write",mfd_def_size,MFD_CLOEXEC | MFD_ALLOW_SEALING);p = mfd_assert_mmap_shared(fd);mfd_assert_has_seals(fd, 0);/* Not adding grow/shrink seals makes the future write* seal fail to get added*/mfd_fail_add_seals(fd, F_SEAL_FUTURE_WRITE);mfd_assert_add_seals(fd, F_SEAL_GROW);mfd_assert_has_seals(fd, F_SEAL_GROW);/* Should still fail since shrink seal has* not yet been added*/mfd_fail_add_seals(fd, F_SEAL_FUTURE_WRITE);mfd_assert_add_seals(fd, F_SEAL_SHRINK);mfd_assert_has_seals(fd, F_SEAL_GROW |F_SEAL_SHRINK);/* Now should succeed, also verifies that the seal* could be added with an existing writable mmap*/mfd_assert_add_seals(fd, F_SEAL_FUTURE_WRITE);mfd_assert_has_seals(fd, F_SEAL_SHRINK |F_SEAL_GROW |F_SEAL_FUTURE_WRITE);/* read should pass, writes should fail */mfd_assert_read(fd);mfd_fail_write(fd);munmap(p, mfd_def_size);close(fd);/* Test adding all seals (grow, shrink, future write) at once */fd = mfd_assert_new("kern_memfd_seal_future_write2",mfd_def_size,MFD_CLOEXEC | MFD_ALLOW_SEALING);p = mfd_assert_mmap_shared(fd);mfd_assert_has_seals(fd, 0);mfd_assert_add_seals(fd, F_SEAL_SHRINK |F_SEAL_GROW |F_SEAL_FUTURE_WRITE);mfd_assert_has_seals(fd, F_SEAL_SHRINK |F_SEAL_GROW |F_SEAL_FUTURE_WRITE);/* read should pass, writes should fail */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 +1018,7 @@ int main(int argc, char **argv) test_basic();
test_seal_write();
test_seal_future_write(); test_seal_shrink(); test_seal_grow(); test_seal_resize();-- 2.19.1.331.ge82ca0e54c-goog