[PATCH 3.10 169/173] netfilter: nf_conntrack: use RCU safe kfree for conntrack extensions

Greg Kroah-Hartman
2013-12-02T19:12:32Z

From: Michal Kubecek <mkubecek@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@suse.cz>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
include/net/netfilter/nf_conntrack_extend.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- 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(str
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. */