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 X-Spam-Level: X-Spam-Status: No, score=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 74380C636CA for ; Thu, 15 Jul 2021 18:51:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5B81B613D6 for ; Thu, 15 Jul 2021 18:51:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241045AbhGOSx6 (ORCPT ); Thu, 15 Jul 2021 14:53:58 -0400 Received: from mail.kernel.org ([198.145.29.99]:52374 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240509AbhGOSuW (ORCPT ); Thu, 15 Jul 2021 14:50:22 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id F2CE2613DB; Thu, 15 Jul 2021 18:47:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1626374840; bh=kCdTWq7fWYA1GEGr+aSKfE6tn0rSyjfSV023TumUpz4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FxdVvwQoJ7+xIeQNJoM3eX+g5Ol5bA+oNr5XeRW4CZe6M0LPM1FR+x3/K+zBufPlm T0UDCFDwZfE5S92TTfh+XgBlIcswDTYtwnHA/iT8UPJRBNS+Y/qOiWxWyhu3+fD1uW ZC920FJcyeTzUQSFyTgph6Ms6tz8+XHB6SBhOg9o= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Kees Cook , Alex Deucher , Sasha Levin Subject: [PATCH 5.10 047/215] drm/amd/display: Avoid HDCP over-read and corruption Date: Thu, 15 Jul 2021 20:36:59 +0200 Message-Id: <20210715182607.713417088@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210715182558.381078833@linuxfoundation.org> References: <20210715182558.381078833@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 06888d571b513cbfc0b41949948def6cb81021b2 ] Instead of reading the desired 5 bytes of the actual target field, the code was reading 8. This could result in a corrupted value if the trailing 3 bytes were non-zero, so instead use an appropriately sized and zero-initialized bounce buffer, and read only 5 bytes before casting to u64. Signed-off-by: Kees Cook Signed-off-by: Alex Deucher Signed-off-by: Sasha Levin --- drivers/gpu/drm/amd/display/modules/hdcp/hdcp1_execution.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/amd/display/modules/hdcp/hdcp1_execution.c b/drivers/gpu/drm/amd/display/modules/hdcp/hdcp1_execution.c index f244b72e74e0..53eab2b8e2c8 100644 --- a/drivers/gpu/drm/amd/display/modules/hdcp/hdcp1_execution.c +++ b/drivers/gpu/drm/amd/display/modules/hdcp/hdcp1_execution.c @@ -29,8 +29,10 @@ static inline enum mod_hdcp_status validate_bksv(struct mod_hdcp *hdcp) { uint64_t n = 0; uint8_t count = 0; + u8 bksv[sizeof(n)] = { }; - memcpy(&n, hdcp->auth.msg.hdcp1.bksv, sizeof(uint64_t)); + memcpy(bksv, hdcp->auth.msg.hdcp1.bksv, sizeof(hdcp->auth.msg.hdcp1.bksv)); + n = *(uint64_t *)bksv; while (n) { count++; -- 2.30.2