linux-kernel - Re: [PATCH] drm/i915/gvt/scheduler: fix potential NULL pointer dereference

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 linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <152149459549.3594.15219721825785440264@mail.alporthouse.com>
Date:   Mon, 19 Mar 2018 21:23:15 +0000
From:   Chris Wilson <chris@...is-wilson.co.uk>
To:     "Gustavo A. R. Silva" <gustavo@...eddedor.com>,
        "Zhenyu Wang" <zhenyuw@...ux.intel.com>,
        "Zhi Wang" <zhi.a.wang@...el.com>,
        "Jani Nikula" <jani.nikula@...ux.intel.com>,
        "Joonas Lahtinen" <joonas.lahtinen@...ux.intel.com>,
        "Rodrigo Vivi" <rodrigo.vivi@...el.com>,
        "David Airlie" <airlied@...ux.ie>
Cc:     intel-gvt-dev@...ts.freedesktop.org,
        intel-gfx@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] drm/i915/gvt/scheduler: fix potential NULL pointer dereference

Quoting Gustavo A. R. Silva (2018-03-19 20:50:12)
> Hi Chris,
> 
> On 03/19/2018 03:38 PM, Chris Wilson wrote:
> > Quoting Gustavo A. R. Silva (2018-03-19 19:30:53)
> >> _workload_ is being dereferenced before it is null checked, hence
> >> there is a potential null pointer dereference.
> >>
> >> Fix this by moving the pointer dereference after _workload_ has
> >> been null checked.
> > 
> > The checks are misleading and not required.
> 
> All of them?
> 
> if (!workload || !reg_state || workload->ring_id != RCS)
>         return;

workload can not be NULL (dereference in caller), reg_state can not be
NULL (by construct from kmap()).

It may be not an RCS ring through.
-Chris