linux-kernel - Re: [PATCH] usb: iowarrior: replace kmalloc with kmalloc

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Message-ID: <CAGXu5jJY71FoVrQBXZ=Vx1O90bL3BoyAVBwugfh4XJL84=my0Q@mail.gmail.com>
Date:   Thu, 23 Aug 2018 10:43:41 -0700
From:   Kees Cook <keescook@...omium.org>
To:     "Gustavo A. R. Silva" <gustavo@...eddedor.com>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-usb@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] usb: iowarrior: replace kmalloc with kmalloc_array

On Thu, Aug 23, 2018 at 10:31 AM, Gustavo A. R. Silva
<gustavo@...eddedor.com> 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@...eddedor.com>
> ---
>  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@...omium.org>

Thanks!

-Kees

-- 
Kees Cook
Pixel Security