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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Eric Dumazet <edumazet@google.com>,
	"David S . Miller" <davem@davemloft.net>,
	Sasha Levin <sashal@kernel.org>,
	linux-wpan@vger.kernel.org, netdev@vger.kernel.org
Subject: [PATCH AUTOSEL 4.4 098/174] inet: frags: call inet_frags_fini() after unregister_pernet_subsys()
Date: Thu, 16 Jan 2020 12:41:35 -0500
Message-ID: <20200116174251.24326-98-sashal@kernel.org> (raw)
In-Reply-To: <20200116174251.24326-1-sashal@kernel.org>

From: Eric Dumazet <edumazet@google.com>

[ Upstream commit ae7352d384a552d8c799c242e74a934809990a71 ]

Both IPv6 and 6lowpan are calling inet_frags_fini() too soon.

inet_frags_fini() is dismantling a kmem_cache, that might be needed
later when unregister_pernet_subsys() eventually has to remove
frags queues from hash tables and free them.

This fixes potential use-after-free, and is a prereq for the following patch.

Fixes: d4ad4d22e7ac ("inet: frags: use kmem_cache for inet_frag_queue")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/ieee802154/6lowpan/reassembly.c | 2 +-
 net/ipv6/reassembly.c               | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/ieee802154/6lowpan/reassembly.c b/net/ieee802154/6lowpan/reassembly.c
index 6183730d38db..e728dae467c3 100644
--- a/net/ieee802154/6lowpan/reassembly.c
+++ b/net/ieee802154/6lowpan/reassembly.c
@@ -634,7 +634,7 @@ int __init lowpan_net_frag_init(void)
 
 void lowpan_net_frag_exit(void)
 {
-	inet_frags_fini(&lowpan_frags);
 	lowpan_frags_sysctl_unregister();
 	unregister_pernet_subsys(&lowpan_frags_ops);
+	inet_frags_fini(&lowpan_frags);
 }
diff --git a/net/ipv6/reassembly.c b/net/ipv6/reassembly.c
index ec917f58d105..17e9ed2edb86 100644
--- a/net/ipv6/reassembly.c
+++ b/net/ipv6/reassembly.c
@@ -774,8 +774,8 @@ int __init ipv6_frag_init(void)
 
 void ipv6_frag_exit(void)
 {
-	inet_frags_fini(&ip6_frags);
 	ip6_frags_sysctl_unregister();
 	unregister_pernet_subsys(&ip6_frags_ops);
 	inet6_del_protocol(&frag_protocol, IPPROTO_FRAGMENT);
+	inet_frags_fini(&ip6_frags);
 }
-- 
2.20.1


      parent reply index

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20200116174251.24326-1-sashal@kernel.org>
2020-01-16 17:41 ` [PATCH AUTOSEL 4.4 079/174] 6lowpan: Off by one handling ->nexthdr Sasha Levin
2020-01-16 17:41 ` Sasha Levin [this message]

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