Re: [PATCH] usb: iowarrior: replace kmalloc with kmalloc_array

[Kees Cook]

On Thu, Aug 23, 2018 at 10:31 AM, Gustavo A. R. Silva
<gustavo@xxxxxxxxxxxxxx> wrote:
> A common flaw in the kernel is integer overflow during memory allocation
> size calculations. In an effort to reduce the frequency of these bugs,
> kmalloc_array was implemented, which allocates memory for an array,
> while at the same time detects integer overflow.
>
> This patch replaces cases of:
>
> kmalloc(a * b, gfp)
>
> with:
>         kmalloc_array(a * b, gfp)

nit: this should be "kmalloc_array(a, b, gfp)" (This was a typo from
my treewide commit message... :P)

> Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>
> ---
>  drivers/usb/misc/iowarrior.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/usb/misc/iowarrior.c b/drivers/usb/misc/iowarrior.c
> index c2991b8..7a22400 100644
> --- a/drivers/usb/misc/iowarrior.c
> +++ b/drivers/usb/misc/iowarrior.c
> @@ -808,7 +808,7 @@ static int iowarrior_probe(struct usb_interface *interface,
>                          dev->int_in_endpoint->bInterval);
>         /* create an internal buffer for interrupt data from the device */
>         dev->read_queue =
> -           kmalloc(((dev->report_size + 1) * MAX_INTERRUPT_BUFFER),
> +           kmalloc_array(dev->report_size + 1, MAX_INTERRUPT_BUFFER,
>                     GFP_KERNEL);

For this patch with the commit log updated:

Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>

Thanks!

-Kees

-- 
Kees Cook
Pixel Security