[PATCH net] sctp: allow receiving msg when TCP-style sk is in CLOSED state

[Xin Long <lucien.xin@gmail.com>]

Commit 141ddefce7c8 ("sctp: change sk state to CLOSED instead of
CLOSING in sctp_sock_migrate") changed sk state to CLOSED if the
assoc is closed when sctp_accept clones a new sk.

If there is still data in sk receive queue, users will not be able
to read it any more, as sctp_recvmsg returns directly if sk state
is CLOSED.

This patch is to add CLOSED state check in sctp_recvmsg to allow
reading data from TCP-style sk with CLOSED state as what TCP does.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
---
 net/sctp/socket.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 8812e1b..9fc417a 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -2079,7 +2079,7 @@ static int sctp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
 	lock_sock(sk);
 
 	if (sctp_style(sk, TCP) && !sctp_sstate(sk, ESTABLISHED) &&
-	    !sctp_sstate(sk, CLOSING)) {
+	    !sctp_sstate(sk, CLOSING) && !sctp_sstate(sk, CLOSED)) {
 		err = -ENOTCONN;
 		goto out;
 	}
-- 
2.1.0