* [PATCH net-next v3] netfilter: Correct calculation using skb->tail and skb-network_header
@ 2013-05-31 2:39 Simon Horman
2013-05-31 23:38 ` David Miller
2013-06-03 9:06 ` Chen Gang
0 siblings, 2 replies; 3+ messages in thread
From: Simon Horman @ 2013-05-31 2:39 UTC (permalink / raw)
To: Pablo Neira Ayuso, David Miller
Cc: netdev, netfilter-devel, Chen Gang, Simon Horman
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.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reported-by: Chen Gang <gang.chen@asianux.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
--
v3
* Add net-next to subject prefix
v2
* Use skb_tail_pointer() to ensure the tail portion of the calculation is
always a pointer - it is not if NET_SKBUFF_DATA_USES_OFFSET is not set.
---
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..85e20a9 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_pointer(skb) - (skb_network_header(skb) + dataoff +
match_offset + match_len));
/* insert data from buffer */
--
1.7.10.4
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH net-next v3] netfilter: Correct calculation using skb->tail and skb-network_header
2013-05-31 2:39 [PATCH net-next v3] netfilter: Correct calculation using skb->tail and skb-network_header Simon Horman
@ 2013-05-31 23:38 ` David Miller
2013-06-03 9:06 ` Chen Gang
1 sibling, 0 replies; 3+ messages in thread
From: David Miller @ 2013-05-31 23:38 UTC (permalink / raw)
To: horms; +Cc: pablo, netdev, netfilter-devel, gang.chen
From: Simon Horman <horms@verge.net.au>
Date: Fri, 31 May 2013 11:39:29 +0900
> 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.
>
> Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
> Reported-by: Chen Gang <gang.chen@asianux.com>
> Signed-off-by: Simon Horman <horms@verge.net.au>
I've applied this directly to net-next, thanks Simon.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH net-next v3] netfilter: Correct calculation using skb->tail and skb-network_header
2013-05-31 2:39 [PATCH net-next v3] netfilter: Correct calculation using skb->tail and skb-network_header Simon Horman
2013-05-31 23:38 ` David Miller
@ 2013-06-03 9:06 ` Chen Gang
1 sibling, 0 replies; 3+ messages in thread
From: Chen Gang @ 2013-06-03 9:06 UTC (permalink / raw)
To: Simon Horman; +Cc: Pablo Neira Ayuso, David Miller, netdev, netfilter-devel
On 05/31/2013 10:39 AM, 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.
>
> Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
> Reported-by: Chen Gang <gang.chen@asianux.com>
> Signed-off-by: Simon Horman <horms@verge.net.au>
>
> --
> v3
> * Add net-next to subject prefix
>
> v2
> * Use skb_tail_pointer() to ensure the tail portion of the calculation is
> always a pointer - it is not if NET_SKBUFF_DATA_USES_OFFSET is not set.
Thanks.
--
Chen Gang
Asianux Corporation
^ permalink raw reply [flat|nested] 3+ messages in thread
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