From: Neil Horman <nhorman@redhat.com>
Date: Thu, 17 Jun 2010 18:24:46 -0400
Subject: [net] sctp: fix length checks
Message-id: <20100617182446.GD20273@shamino.rdu.redhat.com>
Patchwork-id: 26291
O-Subject: [RHEL5.6 PATCH] sctp: fix length checks in sctp (bz 605305)
Bugzilla: 605305
RH-Acked-by: Jiri Pirko <jpirko@redhat.com>
RH-Acked-by: Dean Nelson <dnelson@redhat.com>

Hey all-
	I fixed 584658 a while back, but in so doing introduced a length check
issue that was fixed upstream by commit
2e3219b5c8a2e44e0b83ae6e04f52f20a82ac0f2.  This is a backport of that.

Signed-off-by: Jarod Wilson <jarod@redhat.com>

diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
index 7b00643..f4c5110 100644
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -144,7 +144,7 @@ int sctp_init_cause_fixed(struct sctp_chunk *chunk, __be16 cause_code,
 	len = sizeof(sctp_errhdr_t) + paylen;
 	err.length  = htons(len);
 
-	if (skb_tailroom(chunk->skb) >  len)
+	if (skb_tailroom(chunk->skb) < len)
 		return -ENOSPC;
 	chunk->subh.err_hdr = sctp_addto_chunk_fixed(chunk,
 						     sizeof(sctp_errhdr_t),
@@ -1196,7 +1196,7 @@ void *sctp_addto_chunk(struct sctp_chunk *chunk, int len, const void *data)
 void *sctp_addto_chunk_fixed(struct sctp_chunk *chunk,
 			     int len, const void *data)
 {
-	if (skb_tailroom(chunk->skb) > len)
+	if (skb_tailroom(chunk->skb) >= len)
 		return sctp_addto_chunk(chunk, len, data);
 	else
 		return NULL;