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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org,
	stable@vger.kernel.org
Cc: Florian Westphal <fw@strlen.de>,
	Pablo Neira Ayuso <pablo@netfilter.org>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.15 13/76] netfilter: nft_ct: fix l3num expectations with inet pseudo family
Date: Wed, 13 Mar 2024 12:41:20 -0400
Message-ID: <20240313164223.615640-14-sashal@kernel.org>
In-Reply-To: <20240313164223.615640-1-sashal@kernel.org>
References: <20240313164223.615640-1-sashal@kernel.org>
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From: Florian Westphal <fw@strlen.de>

[ Upstream commit 99993789966a6eb4f1295193dc543686899892d3 ]

Following is rejected but should be allowed:

table inet t {
        ct expectation exp1 {
                [..]
                l3proto ip

Valid combos are:
table ip t, l3proto ip
table ip6 t, l3proto ip6
table inet t, l3proto ip OR l3proto ip6

Disallow inet pseudeo family, the l3num must be a on-wire protocol known
to conntrack.

Retain NFPROTO_INET case to make it clear its rejected
intentionally rather as oversight.

Fixes: 8059918a1377 ("netfilter: nft_ct: sanitize layer 3 and 4 protocol number in custom expectations")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/netfilter/nft_ct.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/net/netfilter/nft_ct.c b/net/netfilter/nft_ct.c
index 7c667629c5149..69214993b5a2c 100644
--- a/net/netfilter/nft_ct.c
+++ b/net/netfilter/nft_ct.c
@@ -1192,14 +1192,13 @@ static int nft_ct_expect_obj_init(const struct nft_ctx *ctx,
 	switch (priv->l3num) {
 	case NFPROTO_IPV4:
 	case NFPROTO_IPV6:
-		if (priv->l3num != ctx->family)
-			return -EINVAL;
+		if (priv->l3num == ctx->family || ctx->family == NFPROTO_INET)
+			break;
 
-		fallthrough;
-	case NFPROTO_INET:
-		break;
+		return -EINVAL;
+	case NFPROTO_INET: /* tuple.src.l3num supports NFPROTO_IPV4/6 only */
 	default:
-		return -EOPNOTSUPP;
+		return -EAFNOSUPPORT;
 	}
 
 	priv->l4proto = nla_get_u8(tb[NFTA_CT_EXPECT_L4PROTO]);
-- 
2.43.0