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From:   Colin King <colin.king@canonical.com>
To:     Pablo Neira Ayuso <pablo@netfilter.org>,
        Jozsef Kadlecsik <kadlec@netfilter.org>,
        Florian Westphal <fw@strlen.de>,
        "David S . Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        netfilter-devel@vger.kernel.org, coreteam@netfilter.org,
        netdev@vger.kernel.org
Cc:     kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH][next] etfilter: fix array index out-of-bounds error
Date:   Tue,  8 Jun 2021 16:34:08 +0100
Message-Id: <20210608153408.160652-1-colin.king@canonical.com>
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From: Colin Ian King <colin.king@canonical.com>

Currently the array net->nf.hooks_ipv6 is accessed by index hook
before hook is sanity checked. Fix this by moving the sanity check
to before the array access.

Addresses-Coverity: ("Out-of-bounds access")
Fixes: e2cf17d3774c ("netfilter: add new hook nfnl subsystem")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 net/netfilter/nfnetlink_hook.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/netfilter/nfnetlink_hook.c b/net/netfilter/nfnetlink_hook.c
index 04586dfa2acd..58fda6ac663b 100644
--- a/net/netfilter/nfnetlink_hook.c
+++ b/net/netfilter/nfnetlink_hook.c
@@ -181,9 +181,9 @@ nfnl_hook_entries_head(u8 pf, unsigned int hook, struct net *net, const char *de
 		hook_head = rcu_dereference(net->nf.hooks_ipv4[hook]);
 		break;
 	case NFPROTO_IPV6:
-		hook_head = rcu_dereference(net->nf.hooks_ipv6[hook]);
 		if (hook >= ARRAY_SIZE(net->nf.hooks_ipv6))
 			return ERR_PTR(-EINVAL);
+		hook_head = rcu_dereference(net->nf.hooks_ipv6[hook]);
 		break;
 	case NFPROTO_ARP:
 #ifdef CONFIG_NETFILTER_FAMILY_ARP
-- 
2.31.1