[PATCH] selftests/seccomp: Handle arm32 corner cases better

[Kees Cook]

It turns out arm32 doesn't handle syscall -1 gracefully, so skip testing
for that. Additionally skip tests that depend on clone3 when it is not
available (for example when building the seccomp selftests on an old arm
image without clone3 headers). And improve error reporting for when
nanosleep fails, as seen on arm32 since v5.15.

Cc: Lecopzer Chen <lecopzer.chen at mediatek.com>
Signed-off-by: Kees Cook <keescook at chromium.org>
---
 tools/testing/selftests/seccomp/seccomp_bpf.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c
index f6a04d88e02f..38f651469968 100644
--- a/tools/testing/selftests/seccomp/seccomp_bpf.c
+++ b/tools/testing/selftests/seccomp/seccomp_bpf.c
@@ -2184,6 +2184,9 @@ FIXTURE_TEARDOWN(TRACE_syscall)
 
 TEST(negative_ENOSYS)
 {
+#if defined(__arm__)
+	SKIP(return, "arm32 does not support calling syscall -1");
+#endif
 	/*
 	 * There should be no difference between an "internal" skip
 	 * and userspace asking for syscall "-1".
@@ -3072,7 +3075,8 @@ TEST(syscall_restart)
 		timeout.tv_sec = 1;
 		errno = 0;
 		EXPECT_EQ(0, nanosleep(&timeout, NULL)) {
-			TH_LOG("Call to nanosleep() failed (errno %d)", errno);
+			TH_LOG("Call to nanosleep() failed (errno %d: %s)",
+				errno, strerror(errno));
 		}
 
 		/* Read final sync from parent. */
@@ -3908,6 +3912,9 @@ TEST(user_notification_filter_empty)
 		TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!");
 	}
 
+	if (__NR_clone3 < 0)
+		SKIP(return, "Test not built with clone3 support");
+
 	pid = sys_clone3(&args, sizeof(args));
 	ASSERT_GE(pid, 0);
 
@@ -3962,6 +3969,9 @@ TEST(user_notification_filter_empty_threaded)
 		TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!");
 	}
 
+	if (__NR_clone3 < 0)
+		SKIP(return, "Test not built with clone3 support");
+
 	pid = sys_clone3(&args, sizeof(args));
 	ASSERT_GE(pid, 0);
 
-- 
2.34.1