diff options
| author | Pablo Neira Ayuso <pablo@netfilter.org> | 2026-04-30 17:49:48 +0300 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2026-04-30 18:59:01 +0300 |
| commit | ef4f741e8627512cb8c82f59a1fc7aacd854aadf (patch) | |
| tree | 85a0ddc55a8a03e72c6694e0e20b9d980380b886 | |
| parent | 952e121c96137c73bd3e59bb20a93ef659376947 (diff) | |
| download | linux-ef4f741e8627512cb8c82f59a1fc7aacd854aadf.tar.xz | |
netfilter: flowtable: ensure sufficient headroom in xmit path
Check for headroom and call skb_expand_head() like in the IP output
path to ensure there is sufficient headroom for the mac header when
forwarding this packet as suggested by sashiko.
Fixes: b5964aac51e0 ("netfilter: flowtable: consolidate xmit path")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
| -rw-r--r-- | net/netfilter/nf_flow_table_ip.c | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/net/netfilter/nf_flow_table_ip.c b/net/netfilter/nf_flow_table_ip.c index dbd7644fdbeb..8d5fb7e940a1 100644 --- a/net/netfilter/nf_flow_table_ip.c +++ b/net/netfilter/nf_flow_table_ip.c @@ -471,8 +471,17 @@ struct nf_flow_xmit { static unsigned int nf_flow_queue_xmit(struct net *net, struct sk_buff *skb, struct nf_flow_xmit *xmit) { - skb->dev = xmit->outdev; - dev_hard_header(skb, skb->dev, ntohs(skb->protocol), + struct net_device *dev = xmit->outdev; + unsigned int hh_len = LL_RESERVED_SPACE(dev); + + if (unlikely(skb_headroom(skb) < hh_len && dev->header_ops)) { + skb = skb_expand_head(skb, hh_len); + if (!skb) + return NF_STOLEN; + } + + skb->dev = dev; + dev_hard_header(skb, dev, ntohs(skb->protocol), xmit->dest, xmit->source, skb->len); dev_queue_xmit(skb); |