linux-kernel - Re: [PATCH] drm/nouveau: avoid a use-after-free when BO init fails

Open Source and information security mailing list archives

Date:   Tue, 28 Sep 2021 13:06:53 +0200
From:   Karol Herbst <kherbst@...hat.com>
To:     Lyude Paul <lyude@...hat.com>
Cc:     Jeremy Cline <jcline@...hat.com>, Ben Skeggs <bskeggs@...hat.com>,
        David Airlie <airlied@...ux.ie>,
        nouveau <nouveau@...ts.freedesktop.org>,
        Thierry Reding <treding@...dia.com>,
        LKML <linux-kernel@...r.kernel.org>,
        dri-devel <dri-devel@...ts.freedesktop.org>
Subject: Re: [PATCH] drm/nouveau: avoid a use-after-free when BO init fails

Reviewed-by: Karol Herbst <kherbst@...hat.com>

and queued

On Fri, Mar 26, 2021 at 10:41 PM Lyude Paul <lyude@...hat.com> wrote:
>
> Reviewed-by: Lyude Paul <lyude@...hat.com>
>
> On Wed, 2020-12-02 at 19:02 -0500, Jeremy Cline wrote:
> > nouveau_bo_init() is backed by ttm_bo_init() and ferries its return code
> > back to the caller. On failures, ttm_bo_init() invokes the provided
> > destructor which should de-initialize and free the memory.
> >
> > Thus, when nouveau_bo_init() returns an error the gem object has already
> > been released and the memory freed by nouveau_bo_del_ttm().
> >
> > Fixes: 019cbd4a4feb ("drm/nouveau: Initialize GEM object before TTM object")
> > Cc: Thierry Reding <treding@...dia.com>
> > Signed-off-by: Jeremy Cline <jcline@...hat.com>
> > ---
> >  drivers/gpu/drm/nouveau/nouveau_gem.c | 4 +---
> >  1 file changed, 1 insertion(+), 3 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/nouveau/nouveau_gem.c
> > b/drivers/gpu/drm/nouveau/nouveau_gem.c
> > index 787d05eefd9c..d30157cc7169 100644
> > --- a/drivers/gpu/drm/nouveau/nouveau_gem.c
> > +++ b/drivers/gpu/drm/nouveau/nouveau_gem.c
> > @@ -211,10 +211,8 @@ nouveau_gem_new(struct nouveau_cli *cli, u64 size, int
> > align, uint32_t domain,
> >         }
> >
> >         ret = nouveau_bo_init(nvbo, size, align, domain, NULL, NULL);
> > -       if (ret) {
> > -               nouveau_bo_ref(NULL, &nvbo);
> > +       if (ret)
> >                 return ret;
> > -       }
> >
> >         /* we restrict allowed domains on nv50+ to only the types
> >          * that were requested at creation time.  not possibly on
>
> --
> Sincerely,
>    Lyude Paul (she/her)
>    Software Engineer at Red Hat
>
> Note: I deal with a lot of emails and have a lot of bugs on my plate. If you've
> asked me a question, are waiting for a review/merge on a patch, etc. and I
> haven't responded in a while, please feel free to send me another email to check
> on my status. I don't bite!
>
> _______________________________________________
> dri-devel mailing list
> dri-devel@...ts.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

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