netdev - [patch] cls_u32: signedness bug

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Message-ID: <20101004122836.GB5692@bicker>
Date:	Mon, 4 Oct 2010 14:28:36 +0200
From:	Dan Carpenter <error27@...il.com>
To:	Jamal Hadi Salim <hadi@...erus.ca>
Cc:	"David S. Miller" <davem@...emloft.net>,
	Stephen Hemminger <shemminger@...tta.com>,
	Frans Pop <elendil@...net.nl>, Changli Gao <xiaosuo@...il.com>,
	netdev@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject: [patch] cls_u32: signedness bug

skb_headroom() is unsigned so "skb_headroom(skb) + toff" is also
unsigned and can't be less than zero.  This test was added in 66d50d25:
"u32: negative offset fix"  It was supposed to fix a regression.

Signed-off-by: Dan Carpenter <error27@...il.com>
---
Compile tested only.  Please check.

diff --git a/net/sched/cls_u32.c b/net/sched/cls_u32.c
index 7416a5c..b0c2a82 100644
--- a/net/sched/cls_u32.c
+++ b/net/sched/cls_u32.c
@@ -137,7 +137,7 @@ next_knode:
 			int toff = off + key->off + (off2 & key->offmask);
 			__be32 *data, _data;
 
-			if (skb_headroom(skb) + toff < 0)
+			if (skb_headroom(skb) + toff > INT_MAX)
 				goto out;
 
 			data = skb_header_pointer(skb, toff, 4, &_data);
--
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