From c615c9f3f3cea60279b1bb38e8ef27bd575ecd0c Mon Sep 17 00:00:00 2001
From: Wei Yongjun <yjwei@cn.fujitsu.com>
Date: Thu, 2 Jul 2009 16:57:23 +0000
Subject: [PATCH] xfrm4: fix the ports decode of sctp protocol
The SCTP pushed the skb data above the sctp chunk header, so the check
of pskb_may_pull(skb, xprth + 4 - skb->data) in _decode_session4() will
never return 0 because xprth + 4 - skb->data < 0, the ports decode of
sctp will always fail.
Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/ipv4/xfrm4_policy.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/ipv4/xfrm4_policy.c b/net/ipv4/xfrm4_policy.c
index 60d918c96a4f..0071ee6f441f 100644
--- a/net/ipv4/xfrm4_policy.c
+++ b/net/ipv4/xfrm4_policy.c
@@ -136,7 +136,8 @@ _decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse)
case IPPROTO_TCP:
case IPPROTO_SCTP:
case IPPROTO_DCCP:
- if (pskb_may_pull(skb, xprth + 4 - skb->data)) {
+ if (xprth + 4 < skb->data ||
+ pskb_may_pull(skb, xprth + 4 - skb->data)) {
__be16 *ports = (__be16 *)xprth;
fl->fl_ip_sport = ports[!!reverse];
--
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