4.4-stable review patch. If anyone has any objections, please let me know.
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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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/bridge/br_netfilter_hooks.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-)
--- a/net/bridge/br_netfilter_hooks.c +++ b/net/bridge/br_netfilter_hooks.c @@ -701,18 +701,20 @@ static unsigned int nf_bridge_mtu_reduct
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 (skb_is_gso(skb) || skb->len + mtu_reserved <= 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 <= 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. */