Commit 1200832c authored Apr 24, 2020 by Paolo Abeni Committed by David S. Miller Apr 25, 2020

mptcp: fix race in msk status update



Currently subflow_finish_connect() changes unconditionally
any msk socket status other than TCP_ESTABLISHED.

If an unblocking connect() races with close(), we can end-up
triggering:

IPv4: Attempt to release TCP socket in state 1 00000000e32b8b7e

when the msk socket is disposed.

Be sure to enter the established status only from SYN_SENT.

Fixes: c3c123d1 ("net: mptcp: don't hang in mptcp_sendmsg() after TCP fallback")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent b2768df2

net/mptcp/subflow.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -225,7 +225,7 @@ static void subflow_finish_connect(struct sock sk, const struct sk_buff skb)

		subflow->icsk_af_ops->sk_rx_dst_set(sk, skb);

		if (inet_sk_state_load(parent) != TCP_ESTABLISHED) {
		if (inet_sk_state_load(parent) == TCP_SYN_SENT) {
		inet_sk_state_store(parent, TCP_ESTABLISHED);
		parent->sk_state_change(parent);
		}

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