On 1/16/19 5:44 PM, Tycho Andersen 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@xxxxxxxxxx> 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@xxxxxxxxxxxxxxxxxxxx>
Date: Wed Jan 2 09:48:13 2019 -0800
Merge branch 'next-seccomp' of
git://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' of
git://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]));
But also, is running new tests on an old kernel expected to work? I
didn't know that :).
I am running Linux 5.0-rc2 and not an older kernel.
thanks,
-- Shuah
