Subject: Re: [PATCH] net sched: fix kernel leak in act_police

From: Jeff Mahoney <[email-masked]>
Date: Tue, 31 Aug 2010 19:24:10 -0400

On 08/31/2010 07:21 PM, Jeff Mahoney wrote:
>  While reviewing commit 1c40be12f7d8ca1d387510d39787b12e512a7ce8, I
>  audited other users of tc_action_ops->dump for information leaks.
> 
>  That commit covered almost all of them but act_police still had a leak.
> 
>  opt.limit and opt.capab aren't zeroed out before the structure is
>  passed out.
> 
>  This patch uses the C99 initializers to zero everything unused out.
> 
> Signed-off-by: Jeff Mahoney <[email-masked]>
> Acked-by: Jeff Mahoney <[email-masked]>

Oops. Sorry about the Acked-by. I have a script that I use to rename
patches for inclusion in our trees and it tacks that on. This patch was
just pulled out of our master branch.

- -Jeff

> ---
>  net/sched/act_police.c |   19 ++++++++-----------
>  1 file changed, 8 insertions(+), 11 deletions(-)
> 
> --- a/net/sched/act_police.c
> +++ b/net/sched/act_police.c
> @@ -350,22 +350,19 @@ tcf_act_police_dump(struct sk_buff *skb,
>  {
>  	unsigned char *b = skb_tail_pointer(skb);
>  	struct tcf_police *police = a->priv;
> -	struct tc_police opt;
> +	struct tc_police opt = {
> +		.index = police->tcf_index,
> +		.action = police->tcf_action,
> +		.mtu = police->tcfp_mtu,
> +		.burst = police->tcfp_burst,
> +		.refcnt = police->tcf_refcnt - ref,
> +		.bindcnt = police->tcf_bindcnt - bind,
> +	};
>  
> -	opt.index = police->tcf_index;
> -	opt.action = police->tcf_action;
> -	opt.mtu = police->tcfp_mtu;
> -	opt.burst = police->tcfp_burst;
> -	opt.refcnt = police->tcf_refcnt - ref;
> -	opt.bindcnt = police->tcf_bindcnt - bind;
>  	if (police->tcfp_R_tab)
>  		opt.rate = police->tcfp_R_tab->rate;
> -	else
> -		memset(&opt.rate, 0, sizeof(opt.rate));
>  	if (police->tcfp_P_tab)
>  		opt.peakrate = police->tcfp_P_tab->rate;
> -	else
> -		memset(&opt.peakrate, 0, sizeof(opt.peakrate));
>  	NLA_PUT(skb, TCA_POLICE_TBF, sizeof(opt), &opt);
>  	if (police->tcfp_result)
>  		NLA_PUT_U32(skb, TCA_POLICE_RESULT, police->tcfp_result);

- -- 
Jeff Mahoney
SUSE Labs