Subject: Re: [PATCH 4/4] bonding: fix multiple 3ad mode sysfs race conditions

From: Sergei Shtylyov <[email-masked]>
Date: Wed, 15 May 2013 17:53:41 +0400

Hello.

On 15-05-2013 16:32, Nikolay Aleksandrov wrote:

> When bond_3ad_get_active_agg_info() is used in all show_ad_ functions
> it is not protected against slave manipulation and since it walks over
> the slaves and uses them, this can easily result in NULL pointer
> dereference or use of freed memory.

> Signed-off-by: Nikolay Aleksandrov <[email-masked]>
> ---
>   drivers/net/bonding/bond_sysfs.c | 21 ++++++++++++++++-----
>   1 file changed, 16 insertions(+), 5 deletions(-)

> diff --git a/drivers/net/bonding/bond_sysfs.c b/drivers/net/bonding/bond_sysfs.c
> index 77ea237..81ef36a 100644
> --- a/drivers/net/bonding/bond_sysfs.c
> +++ b/drivers/net/bonding/bond_sysfs.c
[...]
> @@ -1333,7 +1344,7 @@ static ssize_t bonding_show_ad_aggregator(struct device *d,
>   	if (bond->params.mode == BOND_MODE_8023AD) {
>   		struct ad_info ad_info;
>   		count = sprintf(buf, "%d\n",
> -				(bond_3ad_get_active_agg_info(bond, &ad_info))
> +				(get_active_agg_info(bond, &ad_info))
>   				?  0 : ad_info.aggregator_id);
>   	}
>
> @@ -1355,7 +1366,7 @@ static ssize_t bonding_show_ad_num_ports(struct device *d,
>   	if (bond->params.mode == BOND_MODE_8023AD) {
>   		struct ad_info ad_info;
>   		count = sprintf(buf, "%d\n",
> -				(bond_3ad_get_active_agg_info(bond, &ad_info))
> +				(get_active_agg_info(bond, &ad_info))
>   				?  0 : ad_info.ports);
>   	}
>
> @@ -1377,7 +1388,7 @@ static ssize_t bonding_show_ad_actor_key(struct device *d,
>   	if (bond->params.mode == BOND_MODE_8023AD) {
>   		struct ad_info ad_info;
>   		count = sprintf(buf, "%d\n",
> -				(bond_3ad_get_active_agg_info(bond, &ad_info))
> +				(get_active_agg_info(bond, &ad_info))
>   				?  0 : ad_info.actor_key);
>   	}
>
> @@ -1399,7 +1410,7 @@ static ssize_t bonding_show_ad_partner_key(struct device *d,
>   	if (bond->params.mode == BOND_MODE_8023AD) {
>   		struct ad_info ad_info;
>   		count = sprintf(buf, "%d\n",
> -				(bond_3ad_get_active_agg_info(bond, &ad_info))
> +				(get_active_agg_info(bond, &ad_info))
>   				?  0 : ad_info.partner_key);
>   	}

    Perhaps it's time to get rid of the useless parens around function 
call in ?: operator?

WBR, Sergei