4.9-stable review patch. If anyone has any objections, please let me know.
------------------ From: Xin Long <[email protected]> [ Upstream commit 34b2789f1d9bf8dcca9b5cb553d076ca2cd898ee ] Now sctp doesn't check sock's state before listening on it. It could even cause changing a sock with any state to become a listening sock when doing sctp_listen. This patch is to fix it by checking sock's state in sctp_listen, so that it will listen on the sock with right state. Reported-by: Andrey Konovalov <[email protected]> Tested-by: Andrey Konovalov <[email protected]> Signed-off-by: Xin Long <[email protected]> Acked-by: Marcelo Ricardo Leitner <[email protected]> Signed-off-by: David S. Miller <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- net/sctp/socket.c | 3 +++ 1 file changed, 3 insertions(+) --- a/net/sctp/socket.c +++ b/net/sctp/socket.c @@ -6861,6 +6861,9 @@ int sctp_inet_listen(struct socket *sock if (sock->state != SS_UNCONNECTED) goto out; + if (!sctp_sstate(sk, LISTENING) && !sctp_sstate(sk, CLOSED)) + goto out; + /* If backlog is zero, disable listening. */ if (!backlog) { if (sctp_sstate(sk, CLOSED))
