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From: Pablo Neira Ayuso <pablo@netfilter.org>
To: netfilter-devel@vger.kernel.org
Cc: davem@davemloft.net, netdev@vger.kernel.org
Subject: [PATCH 06/10] netfilter: nf_tables: prevent shift wrap in nft_chain_parse_hook()
Date: Mon, 22 Apr 2019 22:47:57 +0200	[thread overview]
Message-ID: <20190422204801.26321-7-pablo@netfilter.org> (raw)
In-Reply-To: <20190422204801.26321-1-pablo@netfilter.org>

From: Dan Carpenter <dan.carpenter@oracle.com>

I believe that "hook->num" can be up to UINT_MAX.  Shifting more than
31 bits would is undefined in C but in practice it would lead to shift
wrapping.  That would lead to an array overflow in nf_tables_addchain():

	ops->hook       = hook.type->hooks[ops->hooknum];

Fixes: fe19c04ca137 ("netfilter: nf_tables: remove nhooks field from struct nft_af_info")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 net/netfilter/nf_tables_api.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index ef7772e976cc..1606eaa5ae0d 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -1545,7 +1545,7 @@ static int nft_chain_parse_hook(struct net *net,
 		if (IS_ERR(type))
 			return PTR_ERR(type);
 	}
-	if (!(type->hook_mask & (1 << hook->num)))
+	if (hook->num > NF_MAX_HOOKS || !(type->hook_mask & (1 << hook->num)))
 		return -EOPNOTSUPP;
 
 	if (type->type == NFT_CHAIN_T_NAT &&
-- 
2.11.0


  parent reply	other threads:[~2019-04-22 20:48 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-22 20:47 [PATCH 00/10] Netfilter/IPVS fixes for net Pablo Neira Ayuso
2019-04-22 20:47 ` [PATCH 01/10] selftests: netfilter: check icmp pkttoobig errors are set as related Pablo Neira Ayuso
2019-04-22 20:47 ` [PATCH 02/10] netfilter: conntrack: don't set related state for different outer address Pablo Neira Ayuso
2019-04-22 20:47 ` [PATCH 03/10] netfilter: conntrack: initialize ct->timeout Pablo Neira Ayuso
2019-04-22 20:47 ` [PATCH 04/10] ipvs: do not schedule icmp errors from tunnels Pablo Neira Ayuso
2019-04-22 20:47 ` [PATCH 05/10] netfilter: ctnetlink: don't use conntrack/expect object addresses as id Pablo Neira Ayuso
2019-04-22 20:47 ` Pablo Neira Ayuso [this message]
2019-04-22 20:47 ` [PATCH 07/10] netfilter: nat: fix icmp id randomization Pablo Neira Ayuso
2019-04-22 20:47 ` [PATCH 08/10] netfilter: ebtables: CONFIG_COMPAT: drop a bogus WARN_ON Pablo Neira Ayuso
2019-04-22 20:48 ` [PATCH 09/10] netfilter: never get/set skb->tstamp Pablo Neira Ayuso
2019-04-22 20:48 ` [PATCH 10/10] netfilter: fix nf_l4proto_log_invalid to log invalid packets Pablo Neira Ayuso
2019-04-23  4:25 ` [PATCH 00/10] Netfilter/IPVS fixes for net David Miller

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