From 9754757cc33b53251da8b0adb96e46005768b8c0 Mon Sep 17 00:00:00 2001
From: Pablo Neira Ayuso <pablo@netfilter.org>
Date: Mon, 18 Jun 2012 17:29:53 +0200
Subject: [PATCH] --- yaml --- r: 314316 b: refs/heads/master c:
 32f5376003920a8bc1bd97c6cddcf42df0b6a833 h: refs/heads/master v: v3

---
 [refs]                                    | 2 +-
 trunk/net/netfilter/nf_conntrack_helper.c | 8 +++++++-
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/[refs] b/[refs]
index 8a299fa7ee01..ba37bd1cae16 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: fd7462de461949e36d70f5b0bc17b98c5a00729c
+refs/heads/master: 32f5376003920a8bc1bd97c6cddcf42df0b6a833
diff --git a/trunk/net/netfilter/nf_conntrack_helper.c b/trunk/net/netfilter/nf_conntrack_helper.c
index 2918ec2e4509..c4bc637feb76 100644
--- a/trunk/net/netfilter/nf_conntrack_helper.c
+++ b/trunk/net/netfilter/nf_conntrack_helper.c
@@ -229,7 +229,13 @@ int __nf_ct_try_assign_helper(struct nf_conn *ct, struct nf_conn *tmpl,
 			goto out;
 		}
 	} else {
-		memset(help->data, 0, helper->data_len);
+		/* We only allow helper re-assignment of the same sort since
+		 * we cannot reallocate the helper extension area.
+		 */
+		if (help->helper != helper) {
+			RCU_INIT_POINTER(help->helper, NULL);
+			goto out;
+		}
 	}
 
 	rcu_assign_pointer(help->helper, helper);