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List: netfilter-devel
Subject: [PATCH 4/4] netfilter: ipt_CLUSTERIP: fix buffer overflow
From: kaber () trash ! net
Date: 2011-03-20 15:32:28
Message-ID: 1300635148-22648-5-git-send-email-kaber () trash ! net
[Download RAW message or body]
From: Vasiliy Kulikov <segoon@openwall.com>
'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>
---
net/ipv4/netfilter/ipt_CLUSTERIP.c | 5 ++++-
1 files changed, 4 insertions(+), 1 deletions(-)
diff --git a/net/ipv4/netfilter/ipt_CLUSTERIP.c b/net/ipv4/netfilter/ipt_CLUSTERIP.c
index 403ca57..d609ac3 100644
--- a/net/ipv4/netfilter/ipt_CLUSTERIP.c
+++ b/net/ipv4/netfilter/ipt_CLUSTERIP.c
@@ -664,8 +664,11 @@ 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);
--
1.7.4
--
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