Re: [PATCH 09/18] p54: prevent bounds-check bypass via speculative execution

[Sergei Shtylyov]

On 1/6/2018 4:10 AM, Dan Williams wrote:

> Static analysis reports that 'queue' may be a user controlled value that
> is used as a data dependency to read from the 'priv->qos_params' array.
> In order to avoid potential leaks of kernel memory values, block
> speculative execution of the instruction stream that could issue reads
> based on an invalid result of 'priv->qos_params[queue]'.
>
> Based on an original patch by Elena Reshetova.
>
> Cc: Christian Lamparter <chunkeey@xxxxxxxxxxxxxx>
> Cc: Kalle Valo <kvalo@xxxxxxxxxxxxxx>
> Cc: linux-wireless@xxxxxxxxxxxxxxx
> Cc: netdev@xxxxxxxxxxxxxxx
> Signed-off-by: Elena Reshetova <elena.reshetova@xxxxxxxxx>
> Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
> ---
>   drivers/net/wireless/intersil/p54/main.c |    8 +++++---
>   1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/net/wireless/intersil/p54/main.c b/drivers/net/wireless/intersil/p54/main.c
> index ab6d39e12069..85c9cbee35fc 100644
> --- a/drivers/net/wireless/intersil/p54/main.c
> +++ b/drivers/net/wireless/intersil/p54/main.c
[...]
> @@ -411,12 +412,13 @@ static int p54_conf_tx(struct ieee80211_hw *dev,
>   		       const struct ieee80211_tx_queue_params *params)
>   {
>   	struct p54_common *priv = dev->priv;
> +	struct p54_edcf_queue_param *p54_q;
>   	int ret;
>   
>   	mutex_lock(&priv->conf_mutex);
> -	if (queue < dev->queues) {
> -		P54_SET_QUEUE(priv->qos_params[queue], params->aifs,
> -			params->cw_min, params->cw_max, params->txop);
> +	if ((p54_q = nospec_array_ptr(priv->qos_params, queue, dev->queues))) {

   Same complaint here...

> +		P54_SET_QUEUE(p54_q[0], params->aifs, params->cw_min,
> +				params->cw_max, params->txop);
>   		ret = p54_set_edcf(priv);
>   	} else
>   		ret = -EINVAL;

MBR, Sergei