[PATCH 4.4 069/188] netfilter: nft_exthdr: check for IPv6 packet before further processing

Greg Kroah-Hartman
2021-07-19T15:00:10Z

From: Pablo Neira Ayuso <pablo@netfilter.org>

[ Upstream commit cdd73cc545c0fb9b1a1f7b209f4f536e7990cff4 ]

ipv6_find_hdr() does not validate that this is an IPv6 packet. Add a
sanity check for calling ipv6_find_hdr() to make sure an IPv6 packet
is passed for parsing.

Fixes: 96518518cc41 ("netfilter: add nftables")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/netfilter/nft_exthdr.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/net/netfilter/nft_exthdr.c b/net/netfilter/nft_exthdr.c
index ba7aed13e174..a81f6bf42d1f 100644
--- a/net/netfilter/nft_exthdr.c
+++ b/net/netfilter/nft_exthdr.c
@@ -34,6 +34,9 @@ static void nft_exthdr_eval(const struct nft_expr *expr,
unsigned int offset = 0;
int err;

+ if (pkt->skb->protocol != htons(ETH_P_IPV6))
+ goto err;
+
err = ipv6_find_hdr(pkt->skb, &offset, priv->type, NULL, NULL);
if (err < 0)
goto err;
--
2.30.2