From d351c1ea2de3e36e608fc355d8ae7d0cc80e6cd6 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Sun, 8 Oct 2023 19:36:53 +0200 Subject: netfilter: nft_payload: fix wrong mac header matching MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Signed-off-by: Florian Westphal --- net/netfilter/nft_payload.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net/netfilter/nft_payload.c') 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) && -- cgit