Re: [Qemu-devel] [PATCH v1] arm: check bit index before usage

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

Hi Prasad,

On 22/10/18 20:10, P J P wrote:
> From: Prasad J Pandit <pjp@fedoraproject.org>
> 
> While performing gpio write via strongarm_gpio_handler_update
> routine, the 'bit' index could access beyond s->handler[28] array.
> Add check to avoid OOB access.
> 
> Reported-by: Moguofang <moguofang@huawei.com>
> Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
> ---
>   hw/arm/strongarm.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
> 
> Update v1: use ARRAY_SIZE macro
>    -> https://lists.gnu.org/archive/html/qemu-devel/2018-10/msg04826.html
> 
> diff --git a/hw/arm/strongarm.c b/hw/arm/strongarm.c
> index ec2627374d..9225b1ba6e 100644
> --- a/hw/arm/strongarm.c
> +++ b/hw/arm/strongarm.c
> @@ -532,7 +532,9 @@ static void strongarm_gpio_handler_update(StrongARMGPIOInfo *s)
>   
>       for (diff = s->prev_level ^ level; diff; diff ^= 1 << bit) {
>           bit = ctz32(diff);
> -        qemu_set_irq(s->handler[bit], (level >> bit) & 1);
> +        if (bit < ARRAY_SIZE(s->handler)) {
> +            qemu_set_irq(s->handler[bit], (level >> bit) & 1);

            } else {
                	qemu_log_mask(LOG_GUEST_ERROR, ...

With that:
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>

> +        }
>       }
>   
>       s->prev_level = level;
>