[PATCH 3.11 191/272] netfilter: nf_conntrack: use RCU safe kfree for conntrack extensions

[Luis Henriques]

3.11.10.1 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: =?UTF-8?q?Michal=20Kube=C4=8Dek?= <mkubecek at suse.cz>

commit c13a84a830a208fb3443628773c8ca0557773cc7 upstream.

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 at suse.cz>
Signed-off-by: Pablo Neira Ayuso <pablo at netfilter.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 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. */
-- 
1.8.3.2