From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received-SPF: Pass (sender SPF authorized) identity=mailfrom; client-ip=192.55.52.136; helo=mga12.intel.com; envelope-from=hao.a.wu@intel.com; receiver=edk2-devel@lists.01.org Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 7ADD721184E73 for ; Thu, 15 Nov 2018 17:37:41 -0800 (PST) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 15 Nov 2018 17:37:41 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,238,1539673200"; d="scan'208";a="281527452" Received: from shwdeopenpsi014.ccr.corp.intel.com ([10.239.9.9]) by fmsmga006.fm.intel.com with ESMTP; 15 Nov 2018 17:37:40 -0800 From: Hao Wu To: edk2-devel@lists.01.org Cc: Hao Wu , Star Zeng , Jiewen Yao , Laszlo Ersek Date: Fri, 16 Nov 2018 09:37:36 +0800 Message-Id: <20181116013737.32272-2-hao.a.wu@intel.com> X-Mailer: git-send-email 2.12.0.windows.1 In-Reply-To: <20181116013737.32272-1-hao.a.wu@intel.com> References: <20181116013737.32272-1-hao.a.wu@intel.com> Subject: [PATCH v1 1/2] MdeModulePkg/SmmCorePerfLib: [CVE-2017-5753] Fix bounds check bypass X-BeenThere: edk2-devel@lists.01.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: EDK II Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 16 Nov 2018 01:37:41 -0000 REF:https://bugzilla.tianocore.org/show_bug.cgi?id=1194 Speculative execution is used by processor to avoid having to wait for data to arrive from memory, or for previous operations to finish, the processor may speculate as to what will be executed. If the speculation is incorrect, the speculatively executed instructions might leave hints such as which memory locations have been brought into cache. Malicious actors can use the bounds check bypass method (code gadgets with controlled external inputs) to infer data values that have been used in speculative operations to reveal secrets which should not otherwise be accessed. This commit will focus on the SMI handler(s) registered within the TBD. Hence, this commit adds a AsmLfence() after the boundary/range checks of 'CommBuffer' to prevent the speculative execution. A more detailed explanation of the purpose of commit is under the 'Bounds check bypass mitigation' section of the below link: https://software.intel.com/security-software-guidance/insights/host-firmware-speculative-execution-side-channel-mitigation And the document at: https://software.intel.com/security-software-guidance/api-app/sites/default/files/337879-analyzing-potential-bounds-Check-bypass-vulnerabilities.pdf Cc: Star Zeng Cc: Jiewen Yao Cc: Laszlo Ersek Contributed-under: TianoCore Contribution Agreement 1.1 Signed-off-by: Hao Wu --- MdeModulePkg/Library/SmmCorePerformanceLib/SmmCorePerformanceLib.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/MdeModulePkg/Library/SmmCorePerformanceLib/SmmCorePerformanceLib.c b/MdeModulePkg/Library/SmmCorePerformanceLib/SmmCorePerformanceLib.c index cd1f1a5d5f..63c1eea3a2 100644 --- a/MdeModulePkg/Library/SmmCorePerformanceLib/SmmCorePerformanceLib.c +++ b/MdeModulePkg/Library/SmmCorePerformanceLib/SmmCorePerformanceLib.c @@ -16,7 +16,7 @@ SmmPerformanceHandlerEx(), SmmPerformanceHandler() will receive untrusted input and do basic validation. -Copyright (c) 2011 - 2017, Intel Corporation. All rights reserved.
+Copyright (c) 2011 - 2018, Intel Corporation. All rights reserved.
This program and the accompanying materials are licensed and made available under the terms and conditions of the BSD License which accompanies this distribution. The full text of the license may be found at @@ -538,6 +538,13 @@ SmmPerformanceHandlerEx ( break; } + // + // The AsmLfence() call here is to ensure the previous range/content + // checks for the CommBuffer have been completed before calling + // CopyMem(). + // + AsmLfence (); + GaugeEntryExArray = (GAUGE_DATA_ENTRY_EX *) (mGaugeData + 1); for (Index = 0; Index < NumberOfEntries; Index++) { @@ -650,6 +657,13 @@ SmmPerformanceHandler ( break; } + // + // The AsmLfence() call here is to ensure the previous range/content + // checks for the CommBuffer have been completed before calling + // CopyMem(). + // + AsmLfence (); + GaugeEntryExArray = (GAUGE_DATA_ENTRY_EX *) (mGaugeData + 1); for (Index = 0; Index < NumberOfEntries; Index++) { -- 2.12.0.windows.1