From: Florian Westphal <fw@strlen.de>
To: netfilter-devel <netfilter-devel@vger.kernel.org>
Cc: netfilter@vger.kernel.org, "Florian Westphal" <fw@strlen.de>,
"Blažej Krajňák" <krajnak@levonet.sk>
Subject: [PATCH nf] netfilter: nft_payload: fix wrong mac header matching
Date: Sun, 8 Oct 2023 19:36:53 +0200 [thread overview]
Message-ID: <20231008173730.137689-1-fw@strlen.de> (raw)
In-Reply-To: <7E750C75-70FF-4078-8462-11387E1F1324@levonet.sk>
mcast packets get looped back to the local machine.
Such packets have a 0-length mac header, we should treat
this like "mac header not set" and abort rule evaluation.
As-is, we just copy data from the network header instead.
Fixes: 96518518cc41 ("netfilter: add nftables")
Reported-by: Blažej Krajňák <krajnak@levonet.sk>
Signed-off-by: Florian Westphal <fw@strlen.de>
---
net/netfilter/nft_payload.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/netfilter/nft_payload.c b/net/netfilter/nft_payload.c
index 120f6d395b98..0a689c8e0295 100644
--- a/net/netfilter/nft_payload.c
+++ b/net/netfilter/nft_payload.c
@@ -179,7 +179,7 @@ void nft_payload_eval(const struct nft_expr *expr,
switch (priv->base) {
case NFT_PAYLOAD_LL_HEADER:
- if (!skb_mac_header_was_set(skb))
+ if (!skb_mac_header_was_set(skb) || skb_mac_header_len(skb) == 0)
goto err;
if (skb_vlan_tag_present(skb) &&
--
2.41.0
prev parent reply other threads:[~2023-10-08 17:37 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-08 15:39 Nftables matches IGMP packets as non-IP traffic Blažej Krajňák
2023-10-08 17:36 ` Florian Westphal [this message]
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