'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: NVasiliy Kulikov <segoon@openwall.com>
Acked-by: NChangli Gao <xiaosuo@gmail.com>
Signed-off-by: NPatrick McHardy <kaber@trash.net>