From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pablo Neira Ayuso Subject: [PATCH 1/5] netfilter: ipt_CLUSTERIP: fix use-after-free of proc entry Date: Thu, 24 Aug 2017 16:43:27 +0200 Message-ID: <1503585811-13447-2-git-send-email-pablo@netfilter.org> References: <1503585811-13447-1-git-send-email-pablo@netfilter.org> Cc: davem@davemloft.net, netdev@vger.kernel.org To: netfilter-devel@vger.kernel.org Return-path: Received: from mail.us.es ([193.147.175.20]:50396 "EHLO mail.us.es" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753240AbdHXOno (ORCPT ); Thu, 24 Aug 2017 10:43:44 -0400 Received: from antivirus1-rhel7.int (unknown [192.168.2.11]) by mail.us.es (Postfix) with ESMTP id 037C01BFA8D for ; Thu, 24 Aug 2017 16:43:27 +0200 (CEST) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id EA750DA4CB for ; Thu, 24 Aug 2017 16:43:26 +0200 (CEST) In-Reply-To: <1503585811-13447-1-git-send-email-pablo@netfilter.org> Sender: netfilter-devel-owner@vger.kernel.org List-ID: From: Sabrina Dubroca When we delete a netns with a CLUSTERIP rule, clusterip_net_exit() is called first, removing /proc/net/ipt_CLUSTERIP. Then clusterip_config_entry_put() is called from clusterip_tg_destroy(), and tries to remove its entry under /proc/net/ipt_CLUSTERIP/. Fix this by checking that the parent directory of the entry to remove hasn't already been deleted. The following triggers a KASAN splat (stealing the reproducer from 202f59afd441, thanks to Jianlin Shi and Xin Long): ip netns add test ip link add veth0_in type veth peer name veth0_out ip link set veth0_in netns test ip netns exec test ip link set lo up ip netns exec test ip link set veth0_in up ip netns exec test iptables -I INPUT -d 1.2.3.4 -i veth0_in -j \ CLUSTERIP --new --clustermac 89:d4:47:eb:9a:fa --total-nodes 3 \ --local-node 1 --hashmode sourceip-sourceport ip netns del test Fixes: ce4ff76c15a8 ("netfilter: ipt_CLUSTERIP: make proc directory per net namespace") Signed-off-by: Sabrina Dubroca Reviewed-by: Xin Long Signed-off-by: Pablo Neira Ayuso --- net/ipv4/netfilter/ipt_CLUSTERIP.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/net/ipv4/netfilter/ipt_CLUSTERIP.c b/net/ipv4/netfilter/ipt_CLUSTERIP.c index 7d72decb80f9..efaa04dcc80e 100644 --- a/net/ipv4/netfilter/ipt_CLUSTERIP.c +++ b/net/ipv4/netfilter/ipt_CLUSTERIP.c @@ -117,7 +117,8 @@ clusterip_config_entry_put(struct net *net, struct clusterip_config *c) * functions are also incrementing the refcount on their own, * so it's safe to remove the entry even if it's in use. */ #ifdef CONFIG_PROC_FS - proc_remove(c->pde); + if (cn->procdir) + proc_remove(c->pde); #endif return; } @@ -815,6 +816,7 @@ static void clusterip_net_exit(struct net *net) #ifdef CONFIG_PROC_FS struct clusterip_net *cn = net_generic(net, clusterip_net_id); proc_remove(cn->procdir); + cn->procdir = NULL; #endif nf_unregister_net_hook(net, &cip_arp_ops); } -- 2.1.4