From 8fd563c4a38f2a9d3cec689add4294cbc18a1dad Mon Sep 17 00:00:00 2001
From: Vasiliy Kulikov <segoon@openwall.com>
Date: Sun, 20 Mar 2011 15:42:52 +0100
Subject: [PATCH] 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>
---
net/ipv4/netfilter/ipt_CLUSTERIP.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/net/ipv4/netfilter/ipt_CLUSTERIP.c b/net/ipv4/netfilter/ipt_CLUSTERIP.c
index 2e4f98b85524..edd820536f29 100644
--- a/net/ipv4/netfilter/ipt_CLUSTERIP.c
+++ b/net/ipv4/netfilter/ipt_CLUSTERIP.c
@@ -666,8 +666,11 @@ static ssize_t clusterip_proc_write(struct file *file, const char __user *input,
struct clusterip_config *c = pde->data;
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);
--
2.34.1