netdev - [PATCH net 2/8] netfilter: nf_tables: do not allow SET

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Message-Id: <20220809220532.130240-3-pablo@netfilter.org>
Date:   Wed, 10 Aug 2022 00:05:26 +0200
From:   Pablo Neira Ayuso <pablo@...filter.org>
To:     netfilter-devel@...r.kernel.org
Cc:     davem@...emloft.net, netdev@...r.kernel.org, kuba@...nel.org,
        pabeni@...hat.com, edumazet@...gle.com
Subject: [PATCH net 2/8] netfilter: nf_tables: do not allow SET_ID to refer to another table

From: Thadeu Lima de Souza Cascardo <cascardo@...onical.com>

When doing lookups for sets on the same batch by using its ID, a set from a
different table can be used.

Then, when the table is removed, a reference to the set may be kept after
the set is freed, leading to a potential use-after-free.

When looking for sets by ID, use the table that was used for the lookup by
name, and only return sets belonging to that same table.

This fixes CVE-2022-2586, also reported as ZDI-CAN-17470.

Reported-by: Team Orca of Sea Security (@seasecresponse)
Fixes: 958bee14d071 ("netfilter: nf_tables: use new transaction infrastructure to handle sets")
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@...onical.com>
Cc: <stable@...r.kernel.org>
Signed-off-by: Pablo Neira Ayuso <pablo@...filter.org>
---
 net/netfilter/nf_tables_api.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 3b09e13b9b5c..41c529b0001c 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -3842,6 +3842,7 @@ static struct nft_set *nft_set_lookup_byhandle(const struct nft_table *table,
 }
 
 static struct nft_set *nft_set_lookup_byid(const struct net *net,
+					   const struct nft_table *table,
 					   const struct nlattr *nla, u8 genmask)
 {
 	struct nftables_pernet *nft_net = nft_pernet(net);
@@ -3853,6 +3854,7 @@ static struct nft_set *nft_set_lookup_byid(const struct net *net,
 			struct nft_set *set = nft_trans_set(trans);
 
 			if (id == nft_trans_set_id(trans) &&
+			    set->table == table &&
 			    nft_active_genmask(set, genmask))
 				return set;
 		}
@@ -3873,7 +3875,7 @@ struct nft_set *nft_set_lookup_global(const struct net *net,
 		if (!nla_set_id)
 			return set;
 
-		set = nft_set_lookup_byid(net, nla_set_id, genmask);
+		set = nft_set_lookup_byid(net, table, nla_set_id, genmask);
 	}
 	return set;
 }
-- 
2.30.2