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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 7/9] netfilter: ctnetlink: avoid null pointer dereference
Date: Wed, 13 Jun 2018 12:56:58 +0200
Message-ID: <20180613105700.12894-8-pablo@netfilter.org> (raw)
In-Reply-To: <20180613105700.12894-1-pablo@netfilter.org>

From: Florian Westphal <fw@strlen.de>

Dan Carpenter points out that deref occurs after NULL check, we should
re-fetch the pointer and check that instead.

Fixes: 2c205dd3981f7 ("netfilter: add struct nf_nat_hook and use it")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 net/netfilter/nf_conntrack_netlink.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index 39327a42879f..20a2e37c76d1 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -1446,7 +1446,8 @@ ctnetlink_parse_nat_setup(struct nf_conn *ct,
 		}
 		nfnl_lock(NFNL_SUBSYS_CTNETLINK);
 		rcu_read_lock();
-		if (nat_hook->parse_nat_setup)
+		nat_hook = rcu_dereference(nf_nat_hook);
+		if (nat_hook)
 			return -EAGAIN;
 #endif
 		return -EOPNOTSUPP;
-- 
2.11.0

  parent reply index

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-06-13 10:56 [PATCH 0/9] Netfilter fixes for net Pablo Neira Ayuso
2018-06-13 10:56 ` [PATCH 1/9] netfilter: fix null-ptr-deref in nf_nat_decode_session Pablo Neira Ayuso
2018-06-13 10:56 ` [PATCH 2/9] netfilter: nft_socket: fix module autoload Pablo Neira Ayuso
2018-06-13 10:56 ` [PATCH 3/9] netfilter: nft_dynset: do not reject set updates with NFT_SET_EVAL Pablo Neira Ayuso
2018-06-13 10:56 ` [PATCH 4/9] netfilter: nf_tables: fix module unload race Pablo Neira Ayuso
2018-06-13 10:56 ` [PATCH 5/9] netfilter: nf_tables: close race between netns exit and rmmod Pablo Neira Ayuso
2018-06-13 10:56 ` [PATCH 6/9] netfilter: nf_tables: use WARN_ON_ONCE instead of BUG_ON in nft_do_chain() Pablo Neira Ayuso
2018-06-13 10:56 ` Pablo Neira Ayuso [this message]
2018-06-13 10:56 ` [PATCH 8/9] netfilter: xt_connmark: fix list corruption on rmmod Pablo Neira Ayuso
2018-06-13 10:57 ` [PATCH 9/9] netfilter: nf_conncount: Fix garbage collection with zones Pablo Neira Ayuso
2018-06-13 21:05 ` [PATCH 0/9] Netfilter fixes for net David Miller

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