From: Wade Mealing <wmealing@redhat.com>
Date: Wed, 21 Jul 2010 05:46:14 -0400
Subject: [net] hashlimit: check allocation before freeing memory
Message-id: <1279691174-15801-3-git-send-email-wmealing@redhat.com>
Patchwork-id: 26986
O-Subject: [PATCH 2/2] [RHEL 5.6] BZ 615229 Netfilter ipt_hashlimit - check
	allocation correct before freeing memory.
Bugzilla: 615229
RH-Acked-by: David S. Miller <davem@redhat.com>
RH-Acked-by: Jiri Olsa <jolsa@redhat.com>
RH-Acked-by: Jiri Pirko <jpirko@redhat.com>

Red Hat Bugzilla: 615229
Upstream Commit:  55e0d7cf279177dfe320f54816320558bc370f24

This is a backport of Eric Dumazets patch to fix netfilter when attempting
to free an allocation which may have never been allocated.

The upstream patch references net/netfilter/xt_hashlimit.c which was
net/ipv4/netfilter/ipt_hashlimit.c in the RHEL 5 kernel tree.

diff --git a/net/ipv4/netfilter/ipt_hashlimit.c b/net/ipv4/netfilter/ipt_hashlimit.c
index 3bd2368..c77e482 100644
--- a/net/ipv4/netfilter/ipt_hashlimit.c
+++ b/net/ipv4/netfilter/ipt_hashlimit.c
@@ -586,7 +586,8 @@ static void dl_seq_stop(struct seq_file *s, void *v)
 	struct ipt_hashlimit_htable *htable = pde->data;
 	unsigned int *bucket = (unsigned int *)v;
 
-	kfree(bucket);
+	if (!IS_ERR(bucket))
+		kfree(bucket);
 
 	spin_unlock_bh(&htable->lock);
 }