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From: Florian Westphal <fw@strlen.de>
To: <netdev@vger.kernel.org>
Cc: "Paolo Abeni" <pabeni@redhat.com>,
	"David S. Miller" <davem@davemloft.net>,
	"Eric Dumazet" <edumazet@google.com>,
	"Jakub Kicinski" <kuba@kernel.org>,
	netfilter-devel@vger.kernel.org,
	"Blažej Krajňák" <krajnak@levonet.sk>
Subject: [PATCH net 7/7] netfilter: nft_payload: fix wrong mac header matching
Date: Thu, 12 Oct 2023 10:57:10 +0200	[thread overview]
Message-ID: <20231012085724.15155-8-fw@strlen.de> (raw)
In-Reply-To: <20231012085724.15155-1-fw@strlen.de>

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


      parent reply	other threads:[~2023-10-12  8:58 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-10-12  8:57 [PATCH net 0/7] netfilter updates for net Florian Westphal
2023-10-12  8:57 ` [PATCH net 1/7] netfilter: nf_tables: do not remove elements if set backend implements .abort Florian Westphal
2023-10-14  1:00   ` patchwork-bot+netdevbpf
2023-10-12  8:57 ` [PATCH net 2/7] netfilter: nfnetlink_log: silence bogus compiler warning Florian Westphal
2023-10-12  8:57 ` [PATCH net 3/7] netfilter: nf_tables: Annotate struct nft_pipapo_match with __counted_by Florian Westphal
2023-10-12  8:57 ` [PATCH net 4/7] netfilter: nf_tables: do not refresh timeout when resetting element Florian Westphal
2023-10-12  8:57 ` [PATCH net 5/7] nf_tables: fix NULL pointer dereference in nft_inner_init() Florian Westphal
2023-10-12  8:57 ` [PATCH net 6/7] nf_tables: fix NULL pointer dereference in nft_expr_inner_parse() Florian Westphal
2023-10-12  8:57 ` Florian Westphal [this message]

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