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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id f125sm35804175pfa.28.2022.01.05.09.33.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 05 Jan 2022 09:33:19 -0800 (PST) From: Kees Cook To: Maarten Lankhorst Cc: Kees Cook , Maxime Ripard , Thomas Zimmermann , David Airlie , Daniel Vetter , dri-devel@lists.freedesktop.org, stable@vger.kernel.org, "Gustavo A . R . Silva" , Uma Shankar , Jani Nikula , Ankit Nautiyal , linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org Subject: [PATCH v2] drm/dp: Fix off-by-one in register cache size Date: Wed, 5 Jan 2022 09:33:10 -0800 Message-Id: <20220105173310.2420598-1-keescook@chromium.org> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2221; h=from:subject; bh=FKzoP1+Ajq0adEYhRP1CewNZxc4TZAiLM0jC2P8yyAU=; b=owEBbQKS/ZANAwAKAYly9N/cbcAmAcsmYgBh1dZWy/nQqWmat0jak1V87p/MQZdy6f8jwBwkG+sK M0Gs7VmJAjMEAAEKAB0WIQSlw/aPIp3WD3I+bhOJcvTf3G3AJgUCYdXWVgAKCRCJcvTf3G3AJsg9EA CWwI79Dlno4hKxtgvfxb3hGWq5EXAlfZTvAB90dWpess3EFCDDOE5cMKYQKou0opRccmgGwFu0fsPU xTl46z/W9IbbXs5vyTBOJCydBaNUjj/lwR9P7bgXfa0gBoI6WnmZ7gohQ49+LZNEZ4wNJXWFlYzAQ/ s21o7BKnGXrawgnBMpfwz5cUx+rH6xDhJVUZlyJkv4XaRM5iRpLRUB0ViymOvZWZ0iKybHiQcIY8uT QquwLVd/s6X0FmjUuDCbyUbPbgoejl2eVJ6Ugl8cYkm7DwwnJCvG59i6zh+ScjR67ys0ROtApqK7qq NV+g9WC2LY1I+/pAgkTDQqqMD8DUQoKB1hi4qM9o4f9B7bAQW6u98q7bSh55IysN3PSacybx5c+S5g xd920HE37gmARNaJPxZrLm+gVsU3vWtzP4j1FGDZ/hhXb7L+MR5b6iQJl9z/n1Sw9eZRDtz7SdkVOT nmbCgSFtZFyAVGqR3rv9u7KggNppfVXjT+sFCu9UwvwF+uqMWyCHJq0uHEgurEzSFCt25qnartDo2x qxdPe7pjfWgdLa3pGKC4q9FtscpvfXBS/zuuAABJ5sj2Hxhcq8D7Ql0JnuyFTzJexzA8q9iX3gDjBC 2HgLW/d4RUMU9gJcxXqGMY9iXVgEro5Ko3q6xKzx+RkyOZ0SOZ1shTquvgNw== X-Developer-Key: i=keescook@chromium.org; a=openpgp; fpr=A5C3F68F229DD60F723E6E138972F4DFDC6DC026 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-hardening@vger.kernel.org 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 Cc: Maxime Ripard Cc: Thomas Zimmermann Cc: David Airlie Cc: Daniel Vetter Cc: dri-devel@lists.freedesktop.org Fixes: e2e16da398d9 ("drm/dp_helper: Add support for Configuring DSC for HDMI2.1 Pcon") Cc: stable@vger.kernel.org Reviewed-by: Gustavo A. R. Silva Link: https://lore.kernel.org/lkml/20211214001849.GA62559@embeddedor/ Signed-off-by: Kees Cook --- v1: https://lore.kernel.org/lkml/20211203084333.3105038-1-keescook@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