| From | Paul Gortmaker <> | Subject | [34-longterm 040/196] netfilter: ipt_CLUSTERIP: fix buffer overflow | Date | Mon, 12 Mar 2012 20:12:48 -0400 |
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From: Vasiliy Kulikov <segoon@openwall.com>
------------------- This is a commit scheduled for the next v2.6.34 longterm release. If you see a problem with using this for longterm, please comment. -------------------
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: Paul Gortmaker <paul.gortmaker@windriver.com> --- 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 ab82840..e8bd977 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); -- 1.7.9.3
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