Re: [Qemu-block] [Qemu-devel] [PATCH 4/4] vvfat: initialize memory after allocating it

[Philippe Mathieu-Daudé]

Hi Hervé,

On 07/15/2017 10:28 AM, Hervé Poussineau wrote:
> This prevents some host to guest memory content leaks.
>
> Fixes: https://bugs.launchpad.net/qemu/+bug/1599539
>
> Signed-off-by: Hervé Poussineau <address@hidden>
> ---
>   block/vvfat.c | 1 +
>   1 file changed, 1 insertion(+)
>
> diff --git a/block/vvfat.c b/block/vvfat.c
> index afc6170a69..7340decef3 100644
> --- a/block/vvfat.c
> +++ b/block/vvfat.c
> @@ -115,6 +115,7 @@ static inline int array_ensure_allocated(array_t* array, 
> int index)
>           array->pointer = g_realloc(array->pointer, new_size);
>           if (!array->pointer)
>               return -1;

isn't it safer:

if (likely(new_size > array->size)) {

> +        memset(array->pointer + array->size, 0, new_size - array->size);

}

?

>           array->size = new_size;
>           array->next = index + 1;
>       }

Regards,

Phil.