From b8baac3b9c5cc4b261454ff87d75ae8306016ffd Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Tue, 14 Jan 2025 00:50:37 +0100 Subject: [PATCH] netfilter: flowtable: teardown flow if cached mtu is stale Tear down the flow entry in the unlikely case that the interface mtu changes, this gives the flow a chance to refresh the cached mtu, otherwise such refresh does not occur until flow entry expires. Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_flow_table_ip.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/net/netfilter/nf_flow_table_ip.c b/net/netfilter/nf_flow_table_ip.c index 98edcaa37b38..a22856106383 100644 --- a/net/netfilter/nf_flow_table_ip.c +++ b/net/netfilter/nf_flow_table_ip.c @@ -377,8 +377,10 @@ static int nf_flow_offload_forward(struct nf_flowtable_ctx *ctx, flow = container_of(tuplehash, struct flow_offload, tuplehash[dir]); mtu = flow->tuplehash[dir].tuple.mtu + ctx->offset; - if (unlikely(nf_flow_exceeds_mtu(skb, mtu))) + if (unlikely(nf_flow_exceeds_mtu(skb, mtu))) { + flow_offload_teardown(flow); return 0; + } iph = (struct iphdr *)(skb_network_header(skb) + ctx->offset); thoff = (iph->ihl * 4) + ctx->offset; @@ -656,8 +658,10 @@ static int nf_flow_offload_ipv6_forward(struct nf_flowtable_ctx *ctx, flow = container_of(tuplehash, struct flow_offload, tuplehash[dir]); mtu = flow->tuplehash[dir].tuple.mtu + ctx->offset; - if (unlikely(nf_flow_exceeds_mtu(skb, mtu))) + if (unlikely(nf_flow_exceeds_mtu(skb, mtu))) { + flow_offload_teardown(flow); return 0; + } ip6h = (struct ipv6hdr *)(skb_network_header(skb) + ctx->offset); thoff = sizeof(*ip6h) + ctx->offset;