[PATCH 6.6 297/322] netfilter: nft_ct: sanitize layer 3 and 4 protocol number in custom expectations

Greg Kroah-Hartman
2024-02-03T04:15:17Z

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

[ Upstream commit 8059918a1377f2f1fff06af4f5a4ed3d5acd6bc4 ]

- Disallow families other than NFPROTO_{IPV4,IPV6,INET}.
- Disallow layer 4 protocol with no ports, since destination port is a
mandatory attribute for this object.

Fixes: 857b46027d6f ("netfilter: nft_ct: add ct expectations support")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/netfilter/nft_ct.c | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)

diff --git a/net/netfilter/nft_ct.c b/net/netfilter/nft_ct.c
index 86bb9d7797d9..aac98a3c966e 100644
--- a/net/netfilter/nft_ct.c
+++ b/net/netfilter/nft_ct.c
@@ -1250,7 +1250,31 @@ static int nft_ct_expect_obj_init(const struct nft_ctx *ctx,
if (tb[NFTA_CT_EXPECT_L3PROTO])
priv->l3num = ntohs(nla_get_be16(tb[NFTA_CT_EXPECT_L3PROTO]));

+ switch (priv->l3num) {
+ case NFPROTO_IPV4:
+ case NFPROTO_IPV6:
+ if (priv->l3num != ctx->family)
+ return -EINVAL;
+
+ fallthrough;
+ case NFPROTO_INET:
+ break;
+ default:
+ return -EOPNOTSUPP;
+ }
+
priv->l4proto = nla_get_u8(tb[NFTA_CT_EXPECT_L4PROTO]);
+ switch (priv->l4proto) {
+ case IPPROTO_TCP:
+ case IPPROTO_UDP:
+ case IPPROTO_UDPLITE:
+ case IPPROTO_DCCP:
+ case IPPROTO_SCTP:
+ break;
+ default:
+ return -EOPNOTSUPP;
+ }
+
priv->dport = nla_get_be16(tb[NFTA_CT_EXPECT_DPORT]);
priv->timeout = nla_get_u32(tb[NFTA_CT_EXPECT_TIMEOUT]);
priv->size = nla_get_u8(tb[NFTA_CT_EXPECT_SIZE]);
--
2.43.0