From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E073AC433EF for ; Tue, 5 Apr 2022 08:06:37 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 3199110EFFB; Tue, 5 Apr 2022 08:06:37 +0000 (UTC) Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by gabe.freedesktop.org (Postfix) with ESMTPS id 13B2010EFFB for ; Tue, 5 Apr 2022 08:06:35 +0000 (UTC) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id A0140B81BB2; Tue, 5 Apr 2022 08:06:33 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BBFFEC385A2; Tue, 5 Apr 2022 08:06:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1649145992; bh=weF/+fdsg4H1uMnMRru4rmj6Vwi3n8PJR9iKpewABAA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=JNLVnZ2PsQNXsbZz9qt8XLbDMXijzgKvBtJ7/7dUVeyQOcKjWSB9twr++pdn6Wqzl ZUyzSAK5K9uQkST5ZDa3yHAYrTLXA85yi+MOYNYiKOL7wAmTwnfX5xqE7of+Wat8NM gL18VbRq3I7dRUbcRQfL0JXJxpqoOJjd89f+ocvY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Subject: [PATCH 5.17 0604/1126] drm/dp: Fix OOB read when handling Post Cursor2 register Date: Tue, 5 Apr 2022 09:22:31 +0200 Message-Id: <20220405070425.363510901@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220405070407.513532867@linuxfoundation.org> References: <20220405070407.513532867@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Sasha Levin , Thomas Zimmermann , David Airlie , Greg Kroah-Hartman , dri-devel@lists.freedesktop.org, "Gustavo A. R. Silva" , Jani Nikula , stable@vger.kernel.org, Thierry Reding , Kees Cook Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" From: Kees Cook [ Upstream commit a2151490cc6c57b368d7974ffd447a8b36ade639 ] The link_status array was not large enough to read the Adjust Request Post Cursor2 register, so remove the common helper function to avoid an OOB read, found with a -Warray-bounds build: drivers/gpu/drm/drm_dp_helper.c: In function 'drm_dp_get_adjust_request_post_cursor': drivers/gpu/drm/drm_dp_helper.c:59:27: error: array subscript 10 is outside array bounds of 'const u8[6]' {aka 'const unsigned char[6]'} [-Werror=array-bounds] 59 | return link_status[r - DP_LANE0_1_STATUS]; | ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~ drivers/gpu/drm/drm_dp_helper.c:147:51: note: while referencing 'link_status' 147 | u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE], | ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Replace the only user of the helper with an open-coded fetch and decode, similar to drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c. Cc: Daniel Vetter Cc: Maarten Lankhorst Cc: Maxime Ripard Cc: Thomas Zimmermann Cc: David Airlie Cc: dri-devel@lists.freedesktop.org Fixes: 79465e0ffeb9 ("drm/dp: Add helper to get post-cursor adjustments") Signed-off-by: Kees Cook Reviewed-by: Gustavo A. R. Silva Reviewed-by: Jani Nikula Link: https://lore.kernel.org/r/20220105173507.2420910-1-keescook@chromium.org Signed-off-by: Thierry Reding Signed-off-by: Sasha Levin --- drivers/gpu/drm/drm_dp_helper.c | 10 ---------- drivers/gpu/drm/tegra/dp.c | 11 ++++++++++- include/drm/drm_dp_helper.h | 2 -- 3 files changed, 10 insertions(+), 13 deletions(-) diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c index 23f9073bc473..c9528aa62c9c 100644 --- a/drivers/gpu/drm/drm_dp_helper.c +++ b/drivers/gpu/drm/drm_dp_helper.c @@ -144,16 +144,6 @@ u8 drm_dp_get_adjust_tx_ffe_preset(const u8 link_status[DP_LINK_STATUS_SIZE], } EXPORT_SYMBOL(drm_dp_get_adjust_tx_ffe_preset); -u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE], - unsigned int lane) -{ - unsigned int offset = DP_ADJUST_REQUEST_POST_CURSOR2; - u8 value = dp_link_status(link_status, offset); - - return (value >> (lane << 1)) & 0x3; -} -EXPORT_SYMBOL(drm_dp_get_adjust_request_post_cursor); - static int __8b10b_clock_recovery_delay_us(const struct drm_dp_aux *aux, u8 rd_interval) { if (rd_interval > 4) diff --git a/drivers/gpu/drm/tegra/dp.c b/drivers/gpu/drm/tegra/dp.c index 70dfb7d1dec5..f5535eb04c6b 100644 --- a/drivers/gpu/drm/tegra/dp.c +++ b/drivers/gpu/drm/tegra/dp.c @@ -549,6 +549,15 @@ static void drm_dp_link_get_adjustments(struct drm_dp_link *link, { struct drm_dp_link_train_set *adjust = &link->train.adjust; unsigned int i; + u8 post_cursor; + int err; + + err = drm_dp_dpcd_read(link->aux, DP_ADJUST_REQUEST_POST_CURSOR2, + &post_cursor, sizeof(post_cursor)); + if (err < 0) { + DRM_ERROR("failed to read post_cursor2: %d\n", err); + post_cursor = 0; + } for (i = 0; i < link->lanes; i++) { adjust->voltage_swing[i] = @@ -560,7 +569,7 @@ static void drm_dp_link_get_adjustments(struct drm_dp_link *link, DP_TRAIN_PRE_EMPHASIS_SHIFT; adjust->post_cursor[i] = - drm_dp_get_adjust_request_post_cursor(status, i); + (post_cursor >> (i << 1)) & 0x3; } } diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h index 30359e434c3f..28378db676c8 100644 --- a/include/drm/drm_dp_helper.h +++ b/include/drm/drm_dp_helper.h @@ -1528,8 +1528,6 @@ u8 drm_dp_get_adjust_request_pre_emphasis(const u8 link_status[DP_LINK_STATUS_SI int lane); u8 drm_dp_get_adjust_tx_ffe_preset(const u8 link_status[DP_LINK_STATUS_SIZE], int lane); -u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE], - unsigned int lane); #define DP_BRANCH_OUI_HEADER_SIZE 0xc #define DP_RECEIVER_CAP_SIZE 0xf -- 2.34.1 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B18E9C3527D for ; Tue, 5 Apr 2022 10:50:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345115AbiDEKko (ORCPT ); Tue, 5 Apr 2022 06:40:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56394 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237511AbiDEISE (ORCPT ); Tue, 5 Apr 2022 04:18:04 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CEE1D6A021; Tue, 5 Apr 2022 01:06:34 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 85F9DB81B92; Tue, 5 Apr 2022 08:06:33 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BBFFEC385A2; Tue, 5 Apr 2022 08:06:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1649145992; bh=weF/+fdsg4H1uMnMRru4rmj6Vwi3n8PJR9iKpewABAA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=JNLVnZ2PsQNXsbZz9qt8XLbDMXijzgKvBtJ7/7dUVeyQOcKjWSB9twr++pdn6Wqzl ZUyzSAK5K9uQkST5ZDa3yHAYrTLXA85yi+MOYNYiKOL7wAmTwnfX5xqE7of+Wat8NM gL18VbRq3I7dRUbcRQfL0JXJxpqoOJjd89f+ocvY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Daniel Vetter , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , dri-devel@lists.freedesktop.org, Kees Cook , "Gustavo A. R. Silva" , Jani Nikula , Thierry Reding , Sasha Levin Subject: [PATCH 5.17 0604/1126] drm/dp: Fix OOB read when handling Post Cursor2 register Date: Tue, 5 Apr 2022 09:22:31 +0200 Message-Id: <20220405070425.363510901@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220405070407.513532867@linuxfoundation.org> References: <20220405070407.513532867@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Kees Cook [ Upstream commit a2151490cc6c57b368d7974ffd447a8b36ade639 ] The link_status array was not large enough to read the Adjust Request Post Cursor2 register, so remove the common helper function to avoid an OOB read, found with a -Warray-bounds build: drivers/gpu/drm/drm_dp_helper.c: In function 'drm_dp_get_adjust_request_post_cursor': drivers/gpu/drm/drm_dp_helper.c:59:27: error: array subscript 10 is outside array bounds of 'const u8[6]' {aka 'const unsigned char[6]'} [-Werror=array-bounds] 59 | return link_status[r - DP_LANE0_1_STATUS]; | ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~ drivers/gpu/drm/drm_dp_helper.c:147:51: note: while referencing 'link_status' 147 | u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE], | ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Replace the only user of the helper with an open-coded fetch and decode, similar to drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c. Cc: Daniel Vetter Cc: Maarten Lankhorst Cc: Maxime Ripard Cc: Thomas Zimmermann Cc: David Airlie Cc: dri-devel@lists.freedesktop.org Fixes: 79465e0ffeb9 ("drm/dp: Add helper to get post-cursor adjustments") Signed-off-by: Kees Cook Reviewed-by: Gustavo A. R. Silva Reviewed-by: Jani Nikula Link: https://lore.kernel.org/r/20220105173507.2420910-1-keescook@chromium.org Signed-off-by: Thierry Reding Signed-off-by: Sasha Levin --- drivers/gpu/drm/drm_dp_helper.c | 10 ---------- drivers/gpu/drm/tegra/dp.c | 11 ++++++++++- include/drm/drm_dp_helper.h | 2 -- 3 files changed, 10 insertions(+), 13 deletions(-) diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c index 23f9073bc473..c9528aa62c9c 100644 --- a/drivers/gpu/drm/drm_dp_helper.c +++ b/drivers/gpu/drm/drm_dp_helper.c @@ -144,16 +144,6 @@ u8 drm_dp_get_adjust_tx_ffe_preset(const u8 link_status[DP_LINK_STATUS_SIZE], } EXPORT_SYMBOL(drm_dp_get_adjust_tx_ffe_preset); -u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE], - unsigned int lane) -{ - unsigned int offset = DP_ADJUST_REQUEST_POST_CURSOR2; - u8 value = dp_link_status(link_status, offset); - - return (value >> (lane << 1)) & 0x3; -} -EXPORT_SYMBOL(drm_dp_get_adjust_request_post_cursor); - static int __8b10b_clock_recovery_delay_us(const struct drm_dp_aux *aux, u8 rd_interval) { if (rd_interval > 4) diff --git a/drivers/gpu/drm/tegra/dp.c b/drivers/gpu/drm/tegra/dp.c index 70dfb7d1dec5..f5535eb04c6b 100644 --- a/drivers/gpu/drm/tegra/dp.c +++ b/drivers/gpu/drm/tegra/dp.c @@ -549,6 +549,15 @@ static void drm_dp_link_get_adjustments(struct drm_dp_link *link, { struct drm_dp_link_train_set *adjust = &link->train.adjust; unsigned int i; + u8 post_cursor; + int err; + + err = drm_dp_dpcd_read(link->aux, DP_ADJUST_REQUEST_POST_CURSOR2, + &post_cursor, sizeof(post_cursor)); + if (err < 0) { + DRM_ERROR("failed to read post_cursor2: %d\n", err); + post_cursor = 0; + } for (i = 0; i < link->lanes; i++) { adjust->voltage_swing[i] = @@ -560,7 +569,7 @@ static void drm_dp_link_get_adjustments(struct drm_dp_link *link, DP_TRAIN_PRE_EMPHASIS_SHIFT; adjust->post_cursor[i] = - drm_dp_get_adjust_request_post_cursor(status, i); + (post_cursor >> (i << 1)) & 0x3; } } diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h index 30359e434c3f..28378db676c8 100644 --- a/include/drm/drm_dp_helper.h +++ b/include/drm/drm_dp_helper.h @@ -1528,8 +1528,6 @@ u8 drm_dp_get_adjust_request_pre_emphasis(const u8 link_status[DP_LINK_STATUS_SI int lane); u8 drm_dp_get_adjust_tx_ffe_preset(const u8 link_status[DP_LINK_STATUS_SIZE], int lane); -u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE], - unsigned int lane); #define DP_BRANCH_OUI_HEADER_SIZE 0xc #define DP_RECEIVER_CAP_SIZE 0xf -- 2.34.1