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Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.1 MIME-Version: 1.0 In-Reply-To: <20220401220834.307660-5-dverkamp@chromium.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam09 X-Rspam-User: X-Stat-Signature: fppgoe4as9uenta7jizcnjbtpz8g839y Authentication-Results: imf27.hostedemail.com; dkim=pass header.d=linuxfoundation.org header.s=google header.b=L9BQgrut; dmarc=pass (policy=none) header.from=linuxfoundation.org; spf=pass (imf27.hostedemail.com: domain of skhan@linuxfoundation.org designates 209.85.166.45 as permitted sender) smtp.mailfrom=skhan@linuxfoundation.org X-Rspamd-Queue-Id: 60E1C4000D X-HE-Tag: 1649361800-646709 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 4/1/22 4:08 PM, Daniel Verkamp wrote: > Tests that ensure MFD_NOEXEC memfds have the appropriate mode bits and > cannot be chmod-ed into being executable. > > Signed-off-by: Daniel Verkamp > --- > 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 fdb0e46e9df9..a79567161cdf 100644 > --- a/tools/testing/selftests/memfd/memfd_test.c > +++ b/tools/testing/selftests/memfd/memfd_test.c > @@ -32,6 +32,10 @@ > #define F_SEAL_EXEC 0x0020 > #endif > > +#ifndef MFD_NOEXEC > +#define MFD_NOEXEC 0x0008U > +#endif > + > /* > * Default is not to test hugetlbfs > */ > @@ -959,6 +963,35 @@ 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); Don't we need to check fd here? > + 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); What happens when mfd_assert_new() fails - don't we need to check fd? > + 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. > @@ -1132,6 +1165,7 @@ int main(int argc, char **argv) > > test_create(); > test_basic(); > + test_noexec(); > > test_seal_write(); > test_seal_future_write(); > fd isn't checked in the other test F_SEAL_EXEC in the 3/4 patch. thanks, -- Shuah