From: Paolo Abeni pabeni@redhat.com
Fastopen and PM-trigger subflow shutdown can race, as reported by syzkaller.
In my first attempt to close such race, I missed the fact that the subflow status can change again before the subflow_state_change callback is invoked.
Address the issue additionally copying with all the states directly reachable from TCP_FIN_WAIT1.
Fixes: 1e777f39b4d7 ("mptcp: add MSG_FASTOPEN sendmsg flag support") Fixes: 4fd19a307016 ("mptcp: fix inconsistent state on fastopen race") Cc: stable@vger.kernel.org Reported-by: syzbot+c53d4d3ddb327e80bc51@syzkaller.appspotmail.com Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/458 Signed-off-by: Paolo Abeni pabeni@redhat.com Reviewed-by: Mat Martineau martineau@kernel.org Signed-off-by: Matthieu Baerts (NGI0) matttbe@kernel.org --- net/mptcp/protocol.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h index fefcbf585411..ed50f2015dc3 100644 --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -1129,7 +1129,8 @@ static inline bool subflow_simultaneous_connect(struct sock *sk) { struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
- return (1 << sk->sk_state) & (TCPF_ESTABLISHED | TCPF_FIN_WAIT1) && + return (1 << sk->sk_state) & + (TCPF_ESTABLISHED | TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2 | TCPF_CLOSING) && is_active_ssk(subflow) && !subflow->conn_finished; }