From: Florian Westphal fw@strlen.de
[ Upstream commit 4ca60d08cbe65f501baad64af50fceba79c19fbb ]
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: Florian Westphal fw@strlen.de Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org Signed-off-by: Sasha Levin alexander.levin@verizon.com --- net/bridge/br_netfilter_hooks.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/net/bridge/br_netfilter_hooks.c b/net/bridge/br_netfilter_hooks.c index aa1df1a10dd7..82ce5713f744 100644 --- a/net/bridge/br_netfilter_hooks.c +++ b/net/bridge/br_netfilter_hooks.c @@ -706,18 +706,20 @@ 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) { - struct nf_bridge_info *nf_bridge; - unsigned int mtu_reserved; + struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb); + unsigned int mtu, mtu_reserved;
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); 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 * boundaries by preserving frag_list rather than refragmenting. */