Subject: [PATCH 26/55] sctp: fix the issue that the cookie-ack with auth can't get processed

From: Xin Long <[email-masked]>
Date: Wed, 2 May 2018 13:45:12 +0800

[ Upstream commit ce402f044e4e432c296f90eaabb8dbe8f3624391 ]

When auth is enabled for cookie-ack chunk, in sctp_inq_pop, sctp
processes auth chunk first, then continues to the next chunk in
this packet if chunk_end + chunk_hdr size < skb_tail_pointer().
Otherwise, it will go to the next packet or discard this chunk.

However, it missed the fact that cookie-ack chunk's size is equal
to chunk_hdr size, which couldn't match that check, and thus this
chunk would not get processed.

This patch fixes it by changing the check to chunk_end + chunk_hdr
size <= skb_tail_pointer().

Fixes: 26b87c788100 ("net: sctp: fix remote memory pressure from excessive queueing")
Signed-off-by: Xin Long <[email-masked]>
Acked-by: Neil Horman <[email-masked]>
Acked-by: Marcelo Ricardo Leitner <[email-masked]>
Signed-off-by: David S. Miller <[email-masked]>
---
 net/sctp/inqueue.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/sctp/inqueue.c b/net/sctp/inqueue.c
index 23ebc5318edc..eb93ffe2408b 100644
--- a/net/sctp/inqueue.c
+++ b/net/sctp/inqueue.c
@@ -217,7 +217,7 @@ struct sctp_chunk *sctp_inq_pop(struct sctp_inq *queue)
 	skb_pull(chunk->skb, sizeof(*ch));
 	chunk->subh.v = NULL; /* Subheader is no longer valid.  */
 
-	if (chunk->chunk_end + sizeof(*ch) < skb_tail_pointer(chunk->skb)) {
+	if (chunk->chunk_end + sizeof(*ch) <= skb_tail_pointer(chunk->skb)) {
 		/* This is not a singleton */
 		chunk->singleton = 0;
 	} else if (chunk->chunk_end > skb_tail_pointer(chunk->skb)) {
-- 
2.14.3