Re: [PATCH v2] qxl: use kmalloc_array to alloc reloc_info in qxl_process_single_command

[Daniel Vetter]

On Tue, Feb 16, 2016 at 02:25:00PM +0100, Gerd Hoffmann wrote:
> This avoids integer overflows on 32bit machines when calculating
> reloc_info size, as reported by Alan Cox.
> 
> Cc: stable@xxxxxxxxxxxxxxx
> Cc: gnomes@xxxxxxxxxxxxxxxxxxx
> Signed-off-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>

Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx>

> ---
>  drivers/gpu/drm/qxl/qxl_ioctl.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/qxl/qxl_ioctl.c b/drivers/gpu/drm/qxl/qxl_ioctl.c
> index 2ae8577..7c2e782 100644
> --- a/drivers/gpu/drm/qxl/qxl_ioctl.c
> +++ b/drivers/gpu/drm/qxl/qxl_ioctl.c
> @@ -168,7 +168,8 @@ static int qxl_process_single_command(struct qxl_device *qdev,
>  		       cmd->command_size))
>  		return -EFAULT;
>  
> -	reloc_info = kmalloc(sizeof(struct qxl_reloc_info) * cmd->relocs_num, GFP_KERNEL);
> +	reloc_info = kmalloc_array(cmd->relocs_num,
> +				   sizeof(struct qxl_reloc_info), GFP_KERNEL);
>  	if (!reloc_info)
>  		return -ENOMEM;
>  
> -- 
> 1.8.3.1
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch