[PATCH] drm/radeon/kms/atom: check fb scratch array access

[Alex Deucher]

Ignore this.  Better patch coming.

Alex

On Tue, Oct 18, 2011 at 3:56 PM,  <alexdeucher at gmail.com> wrote:
> From: Alex Deucher <alexander.deucher at amd.com>
>
> Check access to the fb scratch array to avoid accessing
> memory past the end of the array.
>
> Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
> Cc: stable at kernel.org
> ---
>  drivers/gpu/drm/radeon/atom.c |   15 +++++++++++++--
>  drivers/gpu/drm/radeon/atom.h |    1 +
>  2 files changed, 14 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/radeon/atom.c b/drivers/gpu/drm/radeon/atom.c
> index e88c644..f69b852 100644
> --- a/drivers/gpu/drm/radeon/atom.c
> +++ b/drivers/gpu/drm/radeon/atom.c
> @@ -277,7 +277,12 @@ static uint32_t atom_get_src_int(atom_exec_context *ctx, uint8_t attr,
>        case ATOM_ARG_FB:
>                idx = U8(*ptr);
>                (*ptr)++;
> -               val = gctx->scratch[((gctx->fb_base + idx) / 4)];
> +               if ((gctx->fb_base + idx) > gctx->scratch_size_bytes) {
> +                       DRM_DEBUG_KMS("ATOM: fb read beyond scratch region: %d vs. %d\n",
> +                                     gctx->fb_base + idx, gctx->scratch_size_bytes);
> +                       val = 0;
> +               } else
> +                       val = gctx->scratch[((gctx->fb_base + idx) / 4)];
>                if (print)
>                        DEBUG("FB[0x%02X]", idx);
>                break;
> @@ -531,7 +536,11 @@ static void atom_put_dst(atom_exec_context *ctx, int arg, uint8_t attr,
>        case ATOM_ARG_FB:
>                idx = U8(*ptr);
>                (*ptr)++;
> -               gctx->scratch[((gctx->fb_base + idx) / 4)] = val;
> +               if ((gctx->fb_base + idx) > gctx->scratch_size_bytes) {
> +                       DRM_DEBUG_KMS("ATOM: fb write beyond scratch region: %d vs. %d\n",
> +                                     gctx->fb_base + idx, gctx->scratch_size_bytes);
> +               } else
> +                       gctx->scratch[((gctx->fb_base + idx) / 4)] = val;
>                DEBUG("FB[0x%02X]", idx);
>                break;
>        case ATOM_ARG_PLL:
> @@ -1370,11 +1379,13 @@ int atom_allocate_fb_scratch(struct atom_context *ctx)
>
>                usage_bytes = firmware_usage->asFirmwareVramReserveInfo[0].usFirmwareUseInKb * 1024;
>        }
> +       ctx->scratch_size_bytes = 0;
>        if (usage_bytes == 0)
>                usage_bytes = 20 * 1024;
>        /* allocate some scratch memory */
>        ctx->scratch = kzalloc(usage_bytes, GFP_KERNEL);
>        if (!ctx->scratch)
>                return -ENOMEM;
> +       ctx->scratch_size_bytes = usage_bytes;
>        return 0;
>  }
> diff --git a/drivers/gpu/drm/radeon/atom.h b/drivers/gpu/drm/radeon/atom.h
> index a589a55..93cfe20 100644
> --- a/drivers/gpu/drm/radeon/atom.h
> +++ b/drivers/gpu/drm/radeon/atom.h
> @@ -137,6 +137,7 @@ struct atom_context {
>        int cs_equal, cs_above;
>        int io_mode;
>        uint32_t *scratch;
> +       int scratch_size_bytes;
>  };
>
>  extern int atom_debug;
> --
> 1.7.1.1
>
>