From: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Date: Mon, 6 Feb 2017 20:10:31 +0000 (-0200)
Subject: sctp: avoid BUG_ON on sctp_wait_for_sndbuf
X-Git-Tag: v3.10.106~13
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1f7cb732afeda60fb18012a79759400f611ab31f;p=thirdparty%2Fkernel%2Fstable.git

sctp: avoid BUG_ON on sctp_wait_for_sndbuf

commit 2dcab598484185dea7ec22219c76dcdd59e3cb90 upstream.

Alexander Popov reported that an application may trigger a BUG_ON in
sctp_wait_for_sndbuf if the socket tx buffer is full, a thread is
waiting on it to queue more data and meanwhile another thread peels off
the association being used by the first thread.

This patch replaces the BUG_ON call with a proper error handling. It
will return -EPIPE to the original sendmsg call, similarly to what would
have been done if the association wasn't found in the first place.

Acked-by: Alexander Popov <alex.popov@linux.com>
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Reviewed-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>
---

diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index ede7c540ea247..152ab4be820c7 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -6724,7 +6724,8 @@ static int sctp_wait_for_sndbuf(struct sctp_association *asoc, long *timeo_p,
 		 */
 		sctp_release_sock(sk);
 		current_timeo = schedule_timeout(current_timeo);
-		BUG_ON(sk != asoc->base.sk);
+		if (sk != asoc->base.sk)
+			goto do_error;
 		sctp_lock_sock(sk);
 
 		*timeo_p = current_timeo;