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authorFlorian Westphal <fw@strlen.de>2022-06-20 16:17:31 +0200
committerPablo Neira Ayuso <pablo@netfilter.org>2022-06-21 10:50:41 +0200
commitfcd53c51d03709bc429822086f1e9b3e88904284 (patch)
tree5befebf050b7a22af1ae20fa3b71d5959e780e0a /net
parent574a5b85dc3b9ab672ff3fba0ee020f927960648 (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.c19
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)