From: Florian Westphal <fw@xxxxxxxxx>
[ Upstream commit fcd53c51d03709bc429822086f1e9b3e88904284 ]
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@xxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
net/netfilter/nf_dup_netdev.c | 19 +++++++++++++++----
1 file 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)
--
2.35.1
