From: Huajian Yang <huajianyang@xxxxxxxxxxxx>
The config NF_CONNTRACK_BRIDGE will change the bridge forwarding for
fragmented packets.
The original bridge does not know that it is a fragmented packet and
forwards it directly, after NF_CONNTRACK_BRIDGE is enabled, function
nf_br_ip_fragment and br_ip6_fragment will check the headroom.
In original br_forward, insufficient headroom of skb may indeed exist,
but there's still a way to save the skb in the device driver after
dev_queue_xmit.So droping the skb will change the original bridge
forwarding in some cases.
Fixes: 3c171f496ef5 ("netfilter: bridge: add connection tracking system")
Signed-off-by: Huajian Yang <huajianyang@xxxxxxxxxxxx>
Reviewed-by: Florian Westphal <fw@xxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
net/bridge/netfilter/nf_conntrack_bridge.c | 12 ++++++------
net/ipv6/netfilter.c | 12 ++++++------
2 files changed, 12 insertions(+), 12 deletions(-)
diff --git a/net/bridge/netfilter/nf_conntrack_bridge.c b/net/bridge/netfilter/nf_conntrack_bridge.c
index 816bb0fde718..6482de4d8750 100644
--- a/net/bridge/netfilter/nf_conntrack_bridge.c
+++ b/net/bridge/netfilter/nf_conntrack_bridge.c
@@ -60,19 +60,19 @@ static int nf_br_ip_fragment(struct net *net, struct sock *sk,
struct ip_fraglist_iter iter;
struct sk_buff *frag;
- if (first_len - hlen > mtu ||
- skb_headroom(skb) < ll_rs)
+ if (first_len - hlen > mtu)
goto blackhole;
- if (skb_cloned(skb))
+ if (skb_cloned(skb) ||
+ skb_headroom(skb) < ll_rs)
goto slow_path;
skb_walk_frags(skb, frag) {
- if (frag->len > mtu ||
- skb_headroom(frag) < hlen + ll_rs)
+ if (frag->len > mtu)
goto blackhole;
- if (skb_shared(frag))
+ if (skb_shared(frag) ||
+ skb_headroom(frag) < hlen + ll_rs)
goto slow_path;
}
diff --git a/net/ipv6/netfilter.c b/net/ipv6/netfilter.c
index 581ce055bf52..4541836ee3da 100644
--- a/net/ipv6/netfilter.c
+++ b/net/ipv6/netfilter.c
@@ -164,20 +164,20 @@ int br_ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
struct ip6_fraglist_iter iter;
struct sk_buff *frag2;
- if (first_len - hlen > mtu ||
- skb_headroom(skb) < (hroom + sizeof(struct frag_hdr)))
+ if (first_len - hlen > mtu)
goto blackhole;
- if (skb_cloned(skb))
+ if (skb_cloned(skb) ||
+ skb_headroom(skb) < (hroom + sizeof(struct frag_hdr)))
goto slow_path;
skb_walk_frags(skb, frag2) {
- if (frag2->len > mtu ||
- skb_headroom(frag2) < (hlen + hroom + sizeof(struct frag_hdr)))
+ if (frag2->len > mtu)
goto blackhole;
/* Partially cloned skb? */
- if (skb_shared(frag2))
+ if (skb_shared(frag2) ||
+ skb_headroom(frag2) < (hlen + hroom + sizeof(struct frag_hdr)))
goto slow_path;
}
--
2.30.2
