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From:   Alex Deucher <alexdeucher@gmail.com>
Date:   Thu, 1 Jul 2021 10:10:47 -0400
Message-ID: <CADnq5_PCZGH=CB5+7kDcpX-7X-uxzB-OeGPavJ3=3tnpyeU54w@mail.gmail.com>
Subject: Re: [PATCH v2] drm/amdgpu: Avoid printing of stack contents on
 firmware load error
To:     Jiri Kosina <jikos@kernel.org>
Cc:     Alex Deucher <alexander.deucher@amd.com>,
        =?UTF-8?Q?Christian_K=C3=B6nig?= <christian.koenig@amd.com>,
        David Airlie <airlied@linux.ie>,
        Vojtech Pavlik <vojtech@ucw.cz>,
        Maling list - DRI developers 
        <dri-devel@lists.freedesktop.org>,
        amd-gfx list <amd-gfx@lists.freedesktop.org>,
        LKML <linux-kernel@vger.kernel.org>
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Precedence: bulk

Applied.  Thanks!

Alex

On Thu, Jul 1, 2021 at 4:33 AM Jiri Kosina <jikos@kernel.org> wrote:
>
> On Thu, 24 Jun 2021, Jiri Kosina wrote:
>
> > From: Jiri Kosina <jkosina@suse.cz>
> >
> > In case when psp_init_asd_microcode() fails to load ASD microcode file,
> > psp_v12_0_init_microcode() tries to print the firmware filename that
> > failed to load before bailing out.
> >
> > This is wrong because:
> >
> > - the firmware filename it would want it print is an incorrect one as
> >   psp_init_asd_microcode() and psp_v12_0_init_microcode() are loading
> >   different filenames
> > - it tries to print fw_name, but that's not yet been initialized by that
> >   time, so it prints random stack contents, e.g.
> >
> >     amdgpu 0000:04:00.0: Direct firmware load for amdgpu/renoir_asd.bin failed with error -2
> >     amdgpu 0000:04:00.0: amdgpu: fail to initialize asd microcode
> >     amdgpu 0000:04:00.0: amdgpu: psp v12.0: Failed to load firmware "\xfeTO\x8e\xff\xff"
> >
> > Fix that by bailing out immediately, instead of priting the bogus error
> > message.
>
> Friendly ping on this one too; priting a few bytes of stack is not a
> *huge* info leak, but I believe it should be fixed nevertheless.
>
> Thanks.
>
> >
> > Reported-by: Vojtech Pavlik <vojtech@ucw.cz>
> > Signed-off-by: Jiri Kosina <jkosina@suse.cz>
>
>
> > ---
> >
> > v1 -> v2: remove now-unused label
> >
> >  drivers/gpu/drm/amd/amdgpu/psp_v12_0.c | 7 +++----
> >  1 file changed, 3 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/amd/amdgpu/psp_v12_0.c b/drivers/gpu/drm/amd/amdgpu/psp_v12_0.c
> > index c4828bd3264b..b0ee77ee80b9 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/psp_v12_0.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/psp_v12_0.c
> > @@ -67,7 +67,7 @@ static int psp_v12_0_init_microcode(struct psp_context *psp)
> >
> >       err = psp_init_asd_microcode(psp, chip_name);
> >       if (err)
> > -             goto out;
> > +             return err;
> >
> >       snprintf(fw_name, sizeof(fw_name), "amdgpu/%s_ta.bin", chip_name);
> >       err = request_firmware(&adev->psp.ta_fw, fw_name, adev->dev);
> > @@ -80,7 +80,7 @@ static int psp_v12_0_init_microcode(struct psp_context *psp)
> >       } else {
> >               err = amdgpu_ucode_validate(adev->psp.ta_fw);
> >               if (err)
> > -                     goto out2;
> > +                     goto out;
> >
> >               ta_hdr = (const struct ta_firmware_header_v1_0 *)
> >                                adev->psp.ta_fw->data;
> > @@ -105,10 +105,9 @@ static int psp_v12_0_init_microcode(struct psp_context *psp)
> >
> >       return 0;
> >
> > -out2:
> > +out:
> >       release_firmware(adev->psp.ta_fw);
> >       adev->psp.ta_fw = NULL;
> > -out:
> >       if (err) {
> >               dev_err(adev->dev,
> >                       "psp v12.0: Failed to load firmware \"%s\"\n",
> > --
> > 2.12.3
> >
>
> --
> Jiri Kosina
> SUSE Labs
>
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