Messages in this thread | | | Date | Tue, 22 Jul 2014 11:52:02 +0300 (EEST) | From | Julian Anastasov <> | Subject | Re: [PATCH 3/5] net/netfilter/ipvs/ip_vs_ctl.c: drop argument range check just before the check for equality |
| |
Hello,
On Tue, 22 Jul 2014, Dan Carpenter wrote:
> On Mon, Jul 21, 2014 at 11:01:56PM +0300, Julian Anastasov wrote: > > @@ -2333,13 +2339,12 @@ do_ip_vs_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len) > > struct ip_vs_dest_user_kern udest; > > struct netns_ipvs *ipvs = net_ipvs(net); > > > > + BUILD_BUG_ON(sizeof(arg) > 256); > > 256 is off-by-one because u8 ranges from 0-255 so we are never able to > copy 256 bytes into the "arg" buffer.
I'll change it to >= 256, to catch that we can not hold such big size in unsigned char [gs]et_arglen and also as an indication that we have to use allocated buffer instead of stack.
> > - if (copylen > 128) > > + if (*len < (int) copylen || *len < 0) { > > + pr_err("get_ctl: len %d < %u\n", *len, copylen); > > Don't let users flood dmesg. Just return an error. (This can be > triggered by non-root as well).
For now both set and get are privileged operations, so we can keep it, it can catch if something wrong happens with the structure sizes.
Regards
-- Julian Anastasov <ja@ssi.bg>
| |