drm/dp: Fix off-by-one in register cache size
commit d4da1f27 upstream. 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: Daniel Vetter <daniel@ffwll.ch> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: Maxime Ripard <mripard@kernel.org> Cc: Thomas Zimmermann <tzimmermann@suse.de> Cc: David Airlie <airlied@linux.ie> Cc: dri-devel@lists.freedesktop.org Fixes: e2e16da3 ("drm/dp_helper: Add support for Configuring DSC for HDMI2.1 Pcon") Cc: stable@vger.kernel.org Reviewed-by:Gustavo A. R. Silva <gustavoars@kernel.org> Link: https://lore.kernel.org/lkml/20211214001849.GA62559@embeddedor/ Signed-off-by:
Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20220105173310.2420598-1-keescook@chromium.org Signed-off-by:
Thierry Reding <treding@nvidia.com> Link: https://patchwork.freedesktop.org/patch/msgid/20220225035610.2552144-2-keescook@chromium.org Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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