From 44ff155c70d7115e14cdf73f77246cf0640e0d8c Mon Sep 17 00:00:00 2001 From: Vasiliy Kulikov Date: Sun, 20 Mar 2011 15:42:52 +0100 Subject: [PATCH] netfilter: ipt_CLUSTERIP: fix buffer overflow BugLink: http://bugs.launchpad.net/bugs/761134 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 Acked-by: Changli Gao Signed-off-by: Patrick McHardy Signed-off-by: Greg Kroah-Hartman Signed-off-by: Tim Gardner --- 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 1e26a48..af7dec6 100644 --- a/net/ipv4/netfilter/ipt_CLUSTERIP.c +++ b/net/ipv4/netfilter/ipt_CLUSTERIP.c @@ -669,8 +669,11 @@ 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); -- 1.7.10.4