diff mbox series

[net-next,6/8] subflow: explicitly check for plain tcp rsk

Message ID 3d0b2caefba40597d5678a4a94ac961a2db6db31.1595431326.git.pabeni@redhat.com
State Accepted
Delegated to: David Miller
Headers show
Series mptcp: non backup subflows pre-reqs | expand

Commit Message

Paolo Abeni July 23, 2020, 11:02 a.m. UTC 
When syncookie are in use, the TCP stack may feed into
subflow_syn_recv_sock() plain TCP request sockets. We can't
access mptcp_subflow_request_sock-specific fields on such
sockets. Explicitly check the rsk ops to do safe accesses.

Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Tested-by: Christoph Paasch <cpaasch@apple.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
 net/mptcp/subflow.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 7f3ef1840df5..3ef445f59556 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -415,7 +415,7 @@  static struct sock *subflow_syn_recv_sock(const struct sock *sk,
 
 	/* hopefully temporary handling for MP_JOIN+syncookie */
 	subflow_req = mptcp_subflow_rsk(req);
-	fallback_is_fatal = subflow_req->mp_join;
+	fallback_is_fatal = tcp_rsk(req)->is_mptcp && subflow_req->mp_join;
 	fallback = !tcp_rsk(req)->is_mptcp;
 	if (fallback)
 		goto create_child;