Commit 4ca60d08 authored by Florian Westphal's avatar Florian Westphal Committed by Pablo Neira Ayuso

netfilter: bridge: honor frag_max_size when refragmenting

consider a bridge with mtu 9000, but end host sending smaller
packets to another host with mtu < 9000.

In this case, after reassembly, bridge+defrag would refragment,
and then attempt to send the reassembled packet as long as it
was below 9k.

Instead we have to cap by the largest fragment size seen.
Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent 10596608
...@@ -721,18 +721,20 @@ static unsigned int nf_bridge_mtu_reduction(const struct sk_buff *skb) ...@@ -721,18 +721,20 @@ static unsigned int nf_bridge_mtu_reduction(const struct sk_buff *skb)
static int br_nf_dev_queue_xmit(struct net *net, struct sock *sk, struct sk_buff *skb) static int br_nf_dev_queue_xmit(struct net *net, struct sock *sk, struct sk_buff *skb)
{ {
struct nf_bridge_info *nf_bridge; struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
unsigned int mtu_reserved; unsigned int mtu, mtu_reserved;
mtu_reserved = nf_bridge_mtu_reduction(skb); mtu_reserved = nf_bridge_mtu_reduction(skb);
mtu = skb->dev->mtu;
if (nf_bridge->frag_max_size && nf_bridge->frag_max_size < mtu)
mtu = nf_bridge->frag_max_size;
if (skb_is_gso(skb) || skb->len + mtu_reserved <= skb->dev->mtu) { if (skb_is_gso(skb) || skb->len + mtu_reserved <= mtu) {
nf_bridge_info_free(skb); nf_bridge_info_free(skb);
return br_dev_queue_push_xmit(net, sk, skb); return br_dev_queue_push_xmit(net, sk, skb);
} }
nf_bridge = nf_bridge_info_get(skb);
/* This is wrong! We should preserve the original fragment /* This is wrong! We should preserve the original fragment
* boundaries by preserving frag_list rather than refragmenting. * boundaries by preserving frag_list rather than refragmenting.
*/ */
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment