lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [day] [month] [year] [list]
Date:	Sun, 24 Aug 2014 19:18:11 +0200
From:	David Herrmann <dh.herrmann@...il.com>
To:	Tommi Rantala <tt.rantala@...il.com>
Cc:	"dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
	trinity@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>,
	David Airlie <airlied@...ux.ie>, Dave Jones <davej@...hat.com>
Subject: Re: drm_mode_create_dumb_ioctl: divide error

Hi

On Sun, Aug 24, 2014 at 7:12 PM, Tommi Rantala <tt.rantala@...il.com> wrote:
> (gdb) info locals
> cpp = 0
> stride = 0
> size = <optimized out>
>
> (gdb) print /x *(struct drm_mode_create_dumb *)data
> $13 = {
>   height = 0xffffffff,
>   width = 0xffffffff,
>   bpp = 0xffffffff,
>   flags = 0xffffffff,
>   handle = 0xffffffff,
>   pitch = 0xffffffff,
>   size = 0xffffffffffffffff
> }

Thanks a lot for digging into this. Looks like DIV_ROUND_UP() can
overflow... *check*
Yes, it's defined as:
        #define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d))

Kinda unexpected that a function called "DIV" can overflow, but makes
sense here. Obvious fix is to test "cpp" for zero. I will send it to
dri-devel.

Thanks!
David
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Powered by blists - more mailing lists