On Wed, Jan 16, 2019 at 4:44 PM Tycho Andersen tycho@tycho.ws wrote:
On Wed, Jan 16, 2019 at 04:30:26PM -0800, Kees Cook wrote:
On Wed, Jan 16, 2019 at 4:01 PM shuah shuah@kernel.org wrote:
Hi Kees and James,
seccomp_bpf test hangs right after the following test passes with EBUSY. Please see log at the end.
/* Installing a second listener in the chain should EBUSY */ EXPECT_EQ(user_trap_syscall(__NR_getpid, SECCOMP_FILTER_FLAG_NEW_LISTENER), -1); EXPECT_EQ(errno, EBUSY);
The user_notification_basic test starts running I assume and then the hang.
The only commit I see that could be suspect is the following as it talks about adding SECCOMP_RET_USER_NOTIF
commit d9a7fa67b4bfe6ce93ee9aab23ae2e7ca0763e84 Merge: f218a29c25ad 55b8cbe470d1 Author: Linus Torvalds torvalds@linux-foundation.org Date: Wed Jan 2 09:48:13 2019 -0800
Merge branch 'next-seccomp' ofgit://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security
Pull seccomp updates from James Morris: - Add SECCOMP_RET_USER_NOTIF - seccomp fixes for sparse warnings and s390 build (Tycho) * 'next-seccomp' ofgit://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: seccomp, s390: fix build for syscall type change seccomp: fix poor type promotion samples: add an example of seccomp user trap seccomp: add a return code to trap to userspace seccomp: switch system call argument type to void * seccomp: hoist struct seccomp_data recalculation higher
Any ideas on how to proceed? Here is the log. The following reproduces the problem.
make -C tools/testing/selftests/seccomp/ run_tests
seccomp_bpf.c:2947:global.get_metadata:Expected 0 (0) == seccomp(SECCOMP_SET_MODE_FILTER, SECCOMP_FILTER_FLAG_LOG, &prog) (18446744073709551615) seccomp_bpf.c:2959:global.get_metadata:Expected 1 (1) == read(pipefd[0], &buf, 1) (0) global.get_metadata: Test terminated by assertion [ FAIL ] global.get_metadata [ RUN ] global.user_notification_basic seccomp_bpf.c:3036:global.user_notification_basic:Expected 0 (0) == WEXITSTATUS(status) (1) seccomp_bpf.c:3039:global.user_notification_basic:Expected seccomp(SECCOMP_SET_MODE_FILTER, 0, &prog) (18446744073709551615) == 0 (0) seccomp_bpf.c:3040:global.user_notification_basic:Expected seccomp(SECCOMP_SET_MODE_FILTER, 0, &prog) (18446744073709551615) == 0 (0) seccomp_bpf.c:3041:global.user_notification_basic:Expected seccomp(SECCOMP_SET_MODE_FILTER, 0, &prog) (18446744073709551615) == 0 (0) seccomp_bpf.c:3042:global.user_notification_basic:Expected seccomp(SECCOMP_SET_MODE_FILTER, 0, &prog) (18446744073709551615) == 0 (0) seccomp_bpf.c:3047:global.user_notification_basic:Expected listener (18446744073709551615) >= 0 (0) seccomp_bpf.c:3053:global.user_notification_basic:Expected errno (13) == EBUSY (16)
Looks like the test is unfriendly when running the current selftest on an old kernel version. A quick look seems like it's missing some ASSERT_* cases where EXPECT_* is used. I'll send a patch.
ASSERT will kill the test case though right? I thought we were supposed to use EXPECT when we wanted it to keep going. In particular, it looks like in the get_metadata test, we should be using expect instead of assert in some places, so we can get to the write() that does the synchronization. Something like,
diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c index 067cb4607d6c..4d2508af2483 100644 --- a/tools/testing/selftests/seccomp/seccomp_bpf.c +++ b/tools/testing/selftests/seccomp/seccomp_bpf.c @@ -2943,11 +2943,11 @@ TEST(get_metadata) };
/* one with log, one without */
ASSERT_EQ(0, seccomp(SECCOMP_SET_MODE_FILTER,
EXPECT_EQ(0, seccomp(SECCOMP_SET_MODE_FILTER, SECCOMP_FILTER_FLAG_LOG, &prog));
ASSERT_EQ(0, seccomp(SECCOMP_SET_MODE_FILTER, 0, &prog));
EXPECT_EQ(0, seccomp(SECCOMP_SET_MODE_FILTER, 0, &prog));
ASSERT_EQ(0, close(pipefd[0]));
EXPECT_EQ(0, close(pipefd[0])); ASSERT_EQ(1, write(pipefd[1], "1", 1)); ASSERT_EQ(0, close(pipefd[1]));
Yeah, if it breaks badly on a failure, let's do it.
But also, is running new tests on an old kernel expected to work? I didn't know that :).
It should at least not hang. :)