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netfilter: nf_queue: fix queueing of bridged gro skbs 

When trying to nf_queue GRO/GSO skbs, nf_queue uses skb_gso_segment
to split the skb.

However, if nf_queue is called via bridge netfilter, the mac header
won't be preserved -- packets will thus contain a bogus mac header.

Fix this by setting skb->data to the mac header when skb->nf_bridge
is set and restoring skb->data afterwards for all segments.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Florian Westphal 2012-02-06 13:23:10 +01:00 committed by Pablo Neira Ayuso
parent e0aac52e17
commit a8db7b2d19
1 changed files with 32 additions and 8 deletions
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40
net/netfilter/nf_queue.c
View File

@ -203,6 +203,27 @@ err:
return status;
}
#ifdef CONFIG_BRIDGE_NETFILTER
/* When called from bridge netfilter, skb->data must point to MAC header
* before calling skb_gso_segment(). Else, original MAC header is lost
* and segmented skbs will be sent to wrong destination.
*/
static void nf_bridge_adjust_skb_data(struct sk_buff *skb)
{
if (skb->nf_bridge)
__skb_push(skb, skb->network_header - skb->mac_header);
}
static void nf_bridge_adjust_segmented_data(struct sk_buff *skb)
{
if (skb->nf_bridge)
__skb_pull(skb, skb->network_header - skb->mac_header);
}
#else
#define nf_bridge_adjust_skb_data(s) do {} while (0)
#define nf_bridge_adjust_segmented_data(s) do {} while (0)
#endif
int nf_queue(struct sk_buff *skb,
struct list_head *elem,
u_int8_t pf, unsigned int hook,
@ -212,7 +233,7 @@ int nf_queue(struct sk_buff *skb,
unsigned int queuenum)
{
struct sk_buff *segs;
int err;
int err = -EINVAL;
unsigned int queued;
if (!skb_is_gso(skb))
@ -228,23 +249,25 @@ int nf_queue(struct sk_buff *skb,
break;
}
nf_bridge_adjust_skb_data(skb);
segs = skb_gso_segment(skb, 0);
/* Does not use PTR_ERR to limit the number of error codes that can be
* returned by nf_queue. For instance, callers rely on -ECANCELED to mean
* 'ignore this hook'.
*/
if (IS_ERR(segs))
return -EINVAL;
goto out_err;
queued = 0;
err = 0;
do {
struct sk_buff *nskb = segs->next;
segs->next = NULL;
if (err == 0)
if (err == 0) {
nf_bridge_adjust_segmented_data(segs);
err = __nf_queue(segs, elem, pf, hook, indev,
outdev, okfn, queuenum);
}
if (err == 0)
queued++;
else
@ -252,11 +275,12 @@ int nf_queue(struct sk_buff *skb,
segs = nskb;
} while (segs);
/* also free orig skb if only some segments were queued */
if (unlikely(err && queued))
err = 0;
if (err == 0)
if (queued) {
kfree_skb(skb);
return 0;
}
out_err:
nf_bridge_adjust_segmented_data(skb);
return err;
}