skb_get_hash() triggers a (harmless) warn when neither skb->sk or skb->dev
is set.
In case of nf-generated tcp reset, both sk and dev are NULL:
WARNING: .. net/core/flow_dissector.c:1104
[..]
skb_flow_dissect_flow_keys include/linux/skbuff.h:1536 [inline]
skb_get_hash include/linux/skbuff.h:1578 [inline]
nft_trace_init+0x7d/0x120 net/netfilter/nf_tables_trace.c:320
nft_do_chain+0xb26/0xb90 net/netfilter/nf_tables_core.c:268
nft_do_chain_ipv4+0x7a/0xa0 net/netfilter/nft_chain_filter.c:23
nf_hook_slow+0x57/0x160 net/netfilter/core.c:626
__ip_local_out+0x21d/0x260 net/ipv4/ip_output.c:118
ip_local_out+0x26/0x1e0 net/ipv4/ip_output.c:127
nf_send_reset+0x58c/0x700 net/ipv4/netfilter/nf_reject_ipv4.c:308
nft_reject_ipv4_eval+0x53/0x90 net/ipv4/netfilter/nft_reject_ipv4.c:30
[..]
Fixes: d0e13a1488ad ("flow_dissector: lookup netns by skb->sk if skb->dev is NULL")
Reported-by: Christoph Paasch <cpaasch@xxxxxxxxx>
Suggested-by: Paolo Abeni <pabeni@xxxxxxxxxx>
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/494
Signed-off-by: Florian Westphal <fw@xxxxxxxxx>
---
net/ipv4/netfilter/nf_reject_ipv4.c | 1 +
net/ipv6/netfilter/nf_reject_ipv6.c | 1 +
2 files changed, 2 insertions(+)
diff --git a/net/ipv4/netfilter/nf_reject_ipv4.c b/net/ipv4/netfilter/nf_reject_ipv4.c
index 04504b2b51df..9333a779eab2 100644
--- a/net/ipv4/netfilter/nf_reject_ipv4.c
+++ b/net/ipv4/netfilter/nf_reject_ipv4.c
@@ -278,6 +278,7 @@ void nf_send_reset(struct net *net, struct sock *sk, struct sk_buff *oldskb,
if (nskb->len > dst_mtu(skb_dst(nskb)))
goto free_nskb;
+ nskb->dev = skb_dst(nskb)->dev;
nf_ct_attach(nskb, oldskb);
nf_ct_set_closing(skb_nfct(oldskb));
diff --git a/net/ipv6/netfilter/nf_reject_ipv6.c b/net/ipv6/netfilter/nf_reject_ipv6.c
index dedee264b8f6..386223311579 100644
--- a/net/ipv6/netfilter/nf_reject_ipv6.c
+++ b/net/ipv6/netfilter/nf_reject_ipv6.c
@@ -334,6 +334,7 @@ void nf_send_reset6(struct net *net, struct sock *sk, struct sk_buff *oldskb,
return;
}
+ nskb->dev = dst->dev;
skb_dst_set(nskb, dst);
nskb->mark = fl6.flowi6_mark;
--
2.44.2
