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authorEvgeniy Polyakov <johnpol@2ka.mipt.ru>2007-08-24 23:36:29 -0700
committerDavid S. Miller <davem@sunset.davemloft.net>2007-08-26 18:35:47 -0700
commite7c243c925f6d9dcb898504ff24d6650b5cbb3b1 (patch)
treef06ae59e206e4876b0326c65811f496a8b1f4bdc /net/bridge
parent7c8347a91dbbb723d8ed106ec817dabac97f2bbc (diff)
[VLAN/BRIDGE]: Fix "skb_pull_rcsum - Fatal exception in interrupt"
I tried to preserve bridging code as it was before, but logic is quite strange - I think we should free skb on error, since it is already unshared and thus will just leak. Herbert Xu states: > + if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) > + goto out; If this happens it'll be a double-free on skb since we'll return NF_DROP which makes the caller free it too. We could return NF_STOLEN to prevent that but I'm not sure whether that's correct netfilter semantics. Patrick, could you please make a call on this? Patrick McHardy states: NF_STOLEN should work fine here. Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/bridge')
-rw-r--r--net/bridge/br_netfilter.c12
1 files changed, 7 insertions, 5 deletions
diff --git a/net/bridge/br_netfilter.c b/net/bridge/br_netfilter.c
index fa779874b9d..3ee2022928e 100644
--- a/net/bridge/br_netfilter.c
+++ b/net/bridge/br_netfilter.c
@@ -509,8 +509,14 @@ static unsigned int br_nf_pre_routing(unsigned int hook, struct sk_buff **pskb,
int (*okfn)(struct sk_buff *))
{
struct iphdr *iph;
- __u32 len;
struct sk_buff *skb = *pskb;
+ __u32 len = nf_bridge_encap_header_len(skb);
+
+ if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
+ return NF_STOLEN;
+
+ if (unlikely(!pskb_may_pull(skb, len)))
+ goto out;
if (skb->protocol == htons(ETH_P_IPV6) || IS_VLAN_IPV6(skb) ||
IS_PPPOE_IPV6(skb)) {
@@ -518,8 +524,6 @@ static unsigned int br_nf_pre_routing(unsigned int hook, struct sk_buff **pskb,
if (!brnf_call_ip6tables)
return NF_ACCEPT;
#endif
- if ((skb = skb_share_check(*pskb, GFP_ATOMIC)) == NULL)
- goto out;
nf_bridge_pull_encap_header_rcsum(skb);
return br_nf_pre_routing_ipv6(hook, skb, in, out, okfn);
}
@@ -532,8 +536,6 @@ static unsigned int br_nf_pre_routing(unsigned int hook, struct sk_buff **pskb,
!IS_PPPOE_IP(skb))
return NF_ACCEPT;
- if ((skb = skb_share_check(*pskb, GFP_ATOMIC)) == NULL)
- goto out;
nf_bridge_pull_encap_header_rcsum(skb);
if (!pskb_may_pull(skb, sizeof(struct iphdr)))