From d01dbeb6af7a0848063033f73c3d146fec7451f3 Mon Sep 17 00:00:00 2001
From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Tue, 30 Sep 2008 02:03:19 -0700
Subject: [PATCH] ipsec: Fix pskb_expand_head corruption in
xfrm_state_check_space
We're never supposed to shrink the headroom or tailroom. In fact,
shrinking the headroom is a fatal action.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/xfrm/xfrm_output.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/net/xfrm/xfrm_output.c b/net/xfrm/xfrm_output.c
index ac25b4c0e982e..dc50f1e71f76f 100644
--- a/net/xfrm/xfrm_output.c
+++ b/net/xfrm/xfrm_output.c
@@ -27,10 +27,14 @@ static int xfrm_state_check_space(struct xfrm_state *x, struct sk_buff *skb)
- skb_headroom(skb);
int ntail = dst->dev->needed_tailroom - skb_tailroom(skb);
- if (nhead > 0 || ntail > 0)
- return pskb_expand_head(skb, nhead, ntail, GFP_ATOMIC);
-
- return 0;
+ if (nhead <= 0) {
+ if (ntail <= 0)
+ return 0;
+ nhead = 0;
+ } else if (ntail < 0)
+ ntail = 0;
+
+ return pskb_expand_head(skb, nhead, ntail, GFP_ATOMIC);
}
static int xfrm_output_one(struct sk_buff *skb, int err)
--
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