diff options
| author | Florian Westphal <fw@strlen.de> | 2022-06-20 16:17:31 +0200 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2022-06-21 10:50:41 +0200 |
| commit | fcd53c51d03709bc429822086f1e9b3e88904284 (patch) | |
| tree | 5befebf050b7a22af1ae20fa3b71d5959e780e0a /net | |
| parent | 574a5b85dc3b9ab672ff3fba0ee020f927960648 (diff) | |
netfilter: nf_dup_netdev: add and use recursion counter
Now that the egress function can be called from egress hook, we need
to avoid recursive calls into the nf_tables traverser, else crash.
Fixes: f87b9464d152 ("netfilter: nft_fwd_netdev: Support egress hook")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/netfilter/nf_dup_netdev.c | 19 |
1 files changed, 15 insertions, 4 deletions
diff --git a/net/netfilter/nf_dup_netdev.c b/net/netfilter/nf_dup_netdev.c index 13b7f6a66086..a8e2425e43b0 100644 --- a/net/netfilter/nf_dup_netdev.c +++ b/net/netfilter/nf_dup_netdev.c @@ -13,20 +13,31 @@ #include <net/netfilter/nf_tables_offload.h> #include <net/netfilter/nf_dup_netdev.h> +#define NF_RECURSION_LIMIT 2 + +static DEFINE_PER_CPU(u8, nf_dup_skb_recursion); + static void nf_do_netdev_egress(struct sk_buff *skb, struct net_device *dev, enum nf_dev_hooks hook) { + if (__this_cpu_read(nf_dup_skb_recursion) > NF_RECURSION_LIMIT) + goto err; + if (hook == NF_NETDEV_INGRESS && skb_mac_header_was_set(skb)) { - if (skb_cow_head(skb, skb->mac_len)) { - kfree_skb(skb); - return; - } + if (skb_cow_head(skb, skb->mac_len)) + goto err; + skb_push(skb, skb->mac_len); } skb->dev = dev; skb_clear_tstamp(skb); + __this_cpu_inc(nf_dup_skb_recursion); dev_queue_xmit(skb); + __this_cpu_dec(nf_dup_skb_recursion); + return; +err: + kfree_skb(skb); } void nf_fwd_netdev_egress(const struct nft_pktinfo *pkt, int oif) |