mptcp: mark as fallback even early ones (0235d075) · Commits · 戴 / test

In the unlikely event of a failure at connect time, we currently clear the request_mptcp flag - so that the MPC handshake is not started at all, but the msk is not explicitly marked as fallback. This would lead to later insertion of wrong DSS options in the xmitted packets, in violation of RFC specs and possibly fooling the peer. Fixes: ("net: mptcp: improve fallback to TCP") 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>

net/mptcp/protocol.c

+9 −2

Original line number	Diff line number	Diff line
		@@ -1944,6 +1944,13 @@ unlock:
		return err;
		}

		static void mptcp_subflow_early_fallback(struct mptcp_sock *msk,
		struct mptcp_subflow_context *subflow)
		{
		subflow->request_mptcp = 0;
		__mptcp_do_fallback(msk);
		}

		static int mptcp_stream_connect(struct socket sock, struct sockaddr uaddr,
		int addr_len, int flags)
		{
		@@ -1975,10 +1982,10 @@ static int mptcp_stream_connect(struct socket sock, struct sockaddr uaddr,
		* TCP option space.
		*/
		if (rcu_access_pointer(tcp_sk(ssock->sk)->md5sig_info))
		subflow->request_mptcp = 0;
		mptcp_subflow_early_fallback(msk, subflow);
		#endif
		if (subflow->request_mptcp && mptcp_token_new_connect(ssock->sk))
		subflow->request_mptcp = 0;
		mptcp_subflow_early_fallback(msk, subflow);

		do_connect:
		err = ssock->ops->connect(ssock, uaddr, addr_len, flags);

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