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

[Philippe Mathieu-Daudé]

Hi Prasad,

On 22/10/18 20:10, P J P wrote:
> From: Prasad J Pandit <address@hidden>
>
> 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 <address@hidden>
> Signed-off-by: Prasad J Pandit <address@hidden>
> ---
>   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 <address@hidden>

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