Ping. This is a OOB read fix. Can something send this to Linus please?
-Kees
On Wed, Jan 05, 2022 at 09:33:10AM -0800, Kees Cook wrote:
> The pcon_dsc_dpcd array holds 13 registers (0x92 through 0x9E). Fix the
> math to calculate the max size. Found from a -Warray-bounds build:
>
> drivers/gpu/drm/drm_dp_helper.c: In function 'drm_dp_pcon_dsc_bpp_incr':
> drivers/gpu/drm/drm_dp_helper.c:3130:28: error: array subscript 12 is outside
> array bounds of 'const u8[12]' {aka 'const unsigned char[12]'}
> [-Werror=array-bounds]
> 3130 | buf = pcon_dsc_dpcd[DP_PCON_DSC_BPP_INCR -
> DP_PCON_DSC_ENCODER];
> |
> ~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/gpu/drm/drm_dp_helper.c:3126:39: note: while referencing
> 'pcon_dsc_dpcd'
> 3126 | int drm_dp_pcon_dsc_bpp_incr(const u8
> pcon_dsc_dpcd[DP_PCON_DSC_ENCODER_CAP_SIZE])
> |
> ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> Cc: Maarten Lankhorst <maarten.lankho...@linux.intel.com>
> Cc: Maxime Ripard <mrip...@kernel.org>
> Cc: Thomas Zimmermann <tzimmerm...@suse.de>
> Cc: David Airlie <airl...@linux.ie>
> Cc: Daniel Vetter <dan...@ffwll.ch>
> Cc: dri-devel@lists.freedesktop.org
> Fixes: e2e16da398d9 ("drm/dp_helper: Add support for Configuring DSC for
> HDMI2.1 Pcon")
> Cc: sta...@vger.kernel.org
> Reviewed-by: Gustavo A. R. Silva <gustavo...@kernel.org>
> Link: https://lore.kernel.org/lkml/20211214001849.GA62559@embeddedor/
> Signed-off-by: Kees Cook <keesc...@chromium.org>
> ---
> v1:
> https://lore.kernel.org/lkml/20211203084333.3105038-1-keesc...@chromium.org/
> v2:
> - add reviewed-by
> - add cc:stable
> ---
> include/drm/drm_dp_helper.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
> index 30359e434c3f..472dac376284 100644
> --- a/include/drm/drm_dp_helper.h
> +++ b/include/drm/drm_dp_helper.h
> @@ -456,7 +456,7 @@ struct drm_panel;
> #define DP_FEC_CAPABILITY_1 0x091 /* 2.0 */
>
> /* DP-HDMI2.1 PCON DSC ENCODER SUPPORT */
> -#define DP_PCON_DSC_ENCODER_CAP_SIZE 0xC /* 0x9E - 0x92 */
> +#define DP_PCON_DSC_ENCODER_CAP_SIZE 0xD /* 0x92 through 0x9E */
> #define DP_PCON_DSC_ENCODER 0x092
> # define DP_PCON_DSC_ENCODER_SUPPORTED (1 << 0)
> # define DP_PCON_DSC_PPS_ENC_OVERRIDE (1 << 1)
> --
> 2.30.2
>
--
Kees Cook
