From: Vasiliy Kulikov <segoon@openwall.com>
Date: Sun, 20 Mar 2011 14:42:52 +0000 (+0100)
Subject: netfilter: ipt_CLUSTERIP: fix buffer overflow
X-Git-Tag: v2.6.35.14~319
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=9c09bd6e205093f8344028671260efd1687f26b9;p=karo-tx-linux.git

netfilter: ipt_CLUSTERIP: fix buffer overflow

commit 961ed183a9fd080cf306c659b8736007e44065a5 upstream.

'buffer' string is copied from userspace.  It is not checked whether it is
zero terminated.  This may lead to overflow inside of simple_strtoul().
Changli Gao suggested to copy not more than user supplied 'size' bytes.

It was introduced before the git epoch.  Files "ipt_CLUSTERIP/*" are
root writable only by default, however, on some setups permissions might be
relaxed to e.g. network admin user.

Signed-off-by: Vasiliy Kulikov <segoon@openwall.com>
Acked-by: Changli Gao <xiaosuo@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
---

diff --git a/net/ipv4/netfilter/ipt_CLUSTERIP.c b/net/ipv4/netfilter/ipt_CLUSTERIP.c
index f91c94b9a790..de773016cbea 100644
--- a/net/ipv4/netfilter/ipt_CLUSTERIP.c
+++ b/net/ipv4/netfilter/ipt_CLUSTERIP.c
@@ -663,8 +663,11 @@ static ssize_t clusterip_proc_write(struct file *file, const char __user *input,
 	char buffer[PROC_WRITELEN+1];
 	unsigned long nodenum;
 
-	if (copy_from_user(buffer, input, PROC_WRITELEN))
+	if (size > PROC_WRITELEN)
+		return -EIO;
+	if (copy_from_user(buffer, input, size))
 		return -EFAULT;
+	buffer[size] = 0;
 
 	if (*buffer == '+') {
 		nodenum = simple_strtoul(buffer+1, NULL, 10);