Commit c0ff6f6d authored by Paolo Abeni's avatar Paolo Abeni Committed by Jakub Kicinski
Browse files

mptcp: fix NULL pointer dereference on fastopen early fallback 



In case of early fallback to TCP, subflow_syn_recv_sock() deletes
the subflow context before returning the newly allocated sock to
the caller.

The fastopen path does not cope with the above unconditionally
dereferencing the subflow context.

Fixes: 36b122ba ("mptcp: add subflow_v(4,6)_send_synack()")
Cc: stable@vger.kernel.org
Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
Reviewed-by: default avatarMatthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: default avatarMatthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent d6a04437

net/mptcp/fastopen.c

+9 −2
Original line number Diff line number Diff line
@@ -9,11 +9,18 @@ 
void mptcp_fastopen_subflow_synack_set_params(struct mptcp_subflow_context *subflow,

					      struct request_sock *req)

{

	struct sock *ssk = subflow->tcp_sock;

	struct sock *sk = subflow->conn;

	struct sock *sk, *ssk;

	struct sk_buff *skb;

	struct tcp_sock *tp;



	/* on early fallback the subflow context is deleted by

	 * subflow_syn_recv_sock()

	 */

	if (!subflow)

		return;



	ssk = subflow->tcp_sock;

	sk = subflow->conn;

	tp = tcp_sk(ssk);



	subflow->is_mptfo = 1;