| Message ID | 20181018065908.254389-2-joel@joelfernandes.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v3,1/2] mm: Add an F_SEAL_FUTURE_WRITE seal to memfd | expand |
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 >
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();