[PATCH net 2/2] selftest: af_unix: Add test case for backtrack after finalising SCC.

From: Shigeru Yoshida
Date: Tue Jul 02 2024 - 12:06:35 EST


From: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>

syzkaller reported a KMSAN splat in __unix_walk_scc() while backtracking
edge_stack after finalising SCC.

Let's add a test case exercising the path.

Signed-off-by: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
Signed-off-by: Shigeru Yoshida <syoshida@xxxxxxxxxx>

diff --git a/tools/testing/selftests/net/af_unix/scm_rights.c b/tools/testing/selftests/net/af_unix/scm_rights.c
index 2bfed46e0b19..d66336256580 100644
--- a/tools/testing/selftests/net/af_unix/scm_rights.c
+++ b/tools/testing/selftests/net/af_unix/scm_rights.c
@@ -14,12 +14,12 @@

FIXTURE(scm_rights)
{
- int fd[16];
+ int fd[32];
};

FIXTURE_VARIANT(scm_rights)
{
- char name[16];
+ char name[32];
int type;
int flags;
bool test_listener;
@@ -172,6 +172,8 @@ static void __create_sockets(struct __test_metadata *_metadata,
const FIXTURE_VARIANT(scm_rights) *variant,
int n)
{
+ ASSERT_LE(n * 2, sizeof(self->fd) / sizeof(self->fd[0]));
+
if (variant->test_listener)
create_listeners(_metadata, self, n);
else
@@ -283,4 +285,23 @@ TEST_F(scm_rights, cross_edge)
close_sockets(8);
}

+TEST_F(scm_rights, backtrack_from_scc)
+{
+ create_sockets(10);
+
+ send_fd(0, 1);
+ send_fd(0, 4);
+ send_fd(1, 2);
+ send_fd(2, 3);
+ send_fd(3, 1);
+
+ send_fd(5, 6);
+ send_fd(5, 9);
+ send_fd(6, 7);
+ send_fd(7, 8);
+ send_fd(8, 6);
+
+ close_sockets(10);
+}
+
TEST_HARNESS_MAIN