Re: [PATCH] netfilter: Correct calculation using skb->tail and skb-network_header
From: Simon Horman <horms@verge.net.au>
Date: 2013-05-30 23:58:32
Also in:
netfilter-devel
On Fri, May 31, 2013 at 08:55:33AM +0900, Simon Horman wrote:
This corrects an regression introduced by "net: Use 16bits for *_headers fields of struct skbuff" when NET_SKBUFF_DATA_USES_OFFSET is not set. In that case skb->tail will be a pointer whereas skb->network_header will be an offset from head. This is corrected by using wrappers that ensure that calculations are always made using pointers.
Sorry, I made this patch in a bit of a rush and I realise it it not always correct as skb->tail is not always a pointer. I will re-spin the patch.
quoted hunk ↗ jump to hunk
Reported-by: Stephen Rothwell <redacted> Reported-by: Chen Gang <redacted> Signed-off-by: Simon Horman <horms@verge.net.au> --- net/netfilter/nf_nat_helper.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)diff --git a/net/netfilter/nf_nat_helper.c b/net/netfilter/nf_nat_helper.c index 5fea563..fdbdfec 100644 --- a/net/netfilter/nf_nat_helper.c +++ b/net/netfilter/nf_nat_helper.c@@ -104,7 +104,7 @@ static void mangle_contents(struct sk_buff *skb, /* move post-replacement */ memmove(data + match_offset + rep_len, data + match_offset + match_len, - skb->tail - (skb->network_header + dataoff + + skb->tail - (skb_network_header(skb) + dataoff + match_offset + match_len)); /* insert data from buffer */-- 1.7.10.4