Commit b7514694 authored Jul 23, 2020 by Paolo Abeni Committed by David S. Miller Jul 23, 2020

subflow: explicitly check for plain tcp rsk



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>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent fa25e815

net/mptcp/subflow.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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;

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