6.6-stable review patch. If anyone has any objections, please let me know.
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From: Paolo Abeni pabeni@redhat.com
commit 337cebbd850f94147cee05252778f8f78b8c337f upstream.
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 Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/mptcp/protocol.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -1104,7 +1104,8 @@ static inline bool subflow_simultaneous_ { 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; }