netdev - [PATCH nf] netfilter: use RCU safe kfree for conntrack extensions

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Message-Id: <20130911090900.0129AE8AFF@unicorn.suse.cz>
Date:	Wed, 11 Sep 2013 10:17:27 +0200
From:	Michal Kubecek <mkubecek@...e.cz>
To:	netfilter-devel@...r.kernel.org
Cc:	netdev@...r.kernel.org, Pablo Neira Ayuso <pablo@...filter.org>,
	Patrick McHardy <kaber@...sh.net>,
	Jozsef Kadlecsik <kadlec@...ckhole.kfki.hu>,
	coreteam@...filter.org
Subject: [PATCH nf] netfilter: use RCU safe kfree for conntrack extensions

Commit 68b80f11 (netfilter: nf_nat: fix RCU races) introduced
RCU protection for freeing extension data when reallocation
moves them to a new location. We need the same protection when
freeing them in nf_ct_ext_free() in order to prevent a
use-after-free by other threads referencing a NAT extension data
via bysource list.

Signed-off-by: Michal Kubecek <mkubecek@...e.cz>
---
 include/net/netfilter/nf_conntrack_extend.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/net/netfilter/nf_conntrack_extend.h b/include/net/netfilter/nf_conntrack_extend.h
index 977bc8a..3313108 100644
--- a/include/net/netfilter/nf_conntrack_extend.h
+++ b/include/net/netfilter/nf_conntrack_extend.h
@@ -80,7 +80,7 @@ static inline void nf_ct_ext_destroy(struct nf_conn *ct)
 static inline void nf_ct_ext_free(struct nf_conn *ct)
 {
 	if (ct->ext)
-		kfree(ct->ext);
+		kfree_rcu(ct->ext, rcu);
 }
 
 /* Add this type, returns pointer to data or NULL. */
-- 
1.8.1.4

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