From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received-SPF: Pass (sender SPF authorized) identity=mailfrom; client-ip=134.134.136.31; helo=mga06.intel.com; envelope-from=liming.gao@intel.com; receiver=edk2-devel@lists.01.org Received: from mga06.intel.com (mga06.intel.com [134.134.136.31]) (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 276C5211648BB for ; Tue, 20 Nov 2018 22:16:16 -0800 (PST) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga104.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 20 Nov 2018 22:16:16 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,260,1539673200"; d="scan'208";a="97909795" Received: from fmsmsx103.amr.corp.intel.com ([10.18.124.201]) by FMSMGA003.fm.intel.com with ESMTP; 20 Nov 2018 22:16:16 -0800 Received: from fmsmsx112.amr.corp.intel.com (10.18.116.6) by FMSMSX103.amr.corp.intel.com (10.18.124.201) with Microsoft SMTP Server (TLS) id 14.3.408.0; Tue, 20 Nov 2018 22:16:15 -0800 Received: from shsmsx102.ccr.corp.intel.com (10.239.4.154) by FMSMSX112.amr.corp.intel.com (10.18.116.6) with Microsoft SMTP Server (TLS) id 14.3.408.0; Tue, 20 Nov 2018 22:16:15 -0800 Received: from shsmsx104.ccr.corp.intel.com ([169.254.5.117]) by shsmsx102.ccr.corp.intel.com ([169.254.2.84]) with mapi id 14.03.0415.000; Wed, 21 Nov 2018 14:16:07 +0800 From: "Gao, Liming" To: "Wu, Hao A" , "edk2-devel@lists.01.org" CC: "Wu, Hao A" , Laszlo Ersek , "Yao, Jiewen" , "Zeng, Star" Thread-Topic: [edk2] [PATCH v2 1/2] MdeModulePkg/SmmCorePerfLib: [CVE-2017-5753] Fix bounds check bypass Thread-Index: AQHUfWKtCDmrxVMIwU6pOmmMz0UZL6VZx/lQ Date: Wed, 21 Nov 2018 06:16:06 +0000 Message-ID: <4A89E2EF3DFEDB4C8BFDE51014F606A14E36F861@SHSMSX104.ccr.corp.intel.com> References: <20181116041242.37604-1-hao.a.wu@intel.com> <20181116041242.37604-2-hao.a.wu@intel.com> In-Reply-To: <20181116041242.37604-2-hao.a.wu@intel.com> Accept-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ctpclassification: CTP_NT x-titus-metadata-40: eyJDYXRlZ29yeUxhYmVscyI6IiIsIk1ldGFkYXRhIjp7Im5zIjoiaHR0cDpcL1wvd3d3LnRpdHVzLmNvbVwvbnNcL0ludGVsMyIsImlkIjoiODA4OGRmNzAtYjUyMy00YTEzLTg4ZmEtZTU3YzU3NzMwMDY5IiwicHJvcHMiOlt7Im4iOiJDVFBDbGFzc2lmaWNhdGlvbiIsInZhbHMiOlt7InZhbHVlIjoiQ1RQX05UIn1dfV19LCJTdWJqZWN0TGFiZWxzIjpbXSwiVE1DVmVyc2lvbiI6IjE3LjEwLjE4MDQuNDkiLCJUcnVzdGVkTGFiZWxIYXNoIjoiQ3NvQlg1Vmlod1A1Rm1SVzBmWlk3VFhTalFubW1VOW84Z1wvd2J1dEJ3WmJzYmlCdHRQYnBXWENTZ0g2UW90M0kifQ== dlp-product: dlpe-windows dlp-version: 11.0.400.15 dlp-reaction: no-action x-originating-ip: [10.239.127.40] MIME-Version: 1.0 Subject: Re: [PATCH v2 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: Wed, 21 Nov 2018 06:16:17 -0000 Content-Language: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Hao: In previous discussion, the suggested subject style is MdeModulePkg/SmmCo= rePerfLib: Fix bounds check bypass(CVE-2017-5753).=20 Thanks Liming > -----Original Message----- > From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of Ha= o Wu > Sent: Friday, November 16, 2018 12:13 PM > To: edk2-devel@lists.01.org > Cc: Wu, Hao A ; Laszlo Ersek ; Yao= , Jiewen ; Zeng, Star > > Subject: [edk2] [PATCH v2 1/2] MdeModulePkg/SmmCorePerfLib: [CVE-2017-575= 3] Fix bounds check bypass >=20 > REF:https://bugzilla.tianocore.org/show_bug.cgi?id=3D1194 >=20 > 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. >=20 > 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. >=20 > This commit will focus on the SMI handler(s) registered within the > SmmCorePerformanceLib and insert AsmLfence API to mitigate the bounds > check bypass issue. >=20 > For SMI handler SmmPerformanceHandlerEx(): >=20 > Under "case SMM_PERF_FUNCTION_GET_GAUGE_DATA :", > 'SmmPerfCommData->LogEntryKey' can be a potential cross boundary access o= f > the 'CommBuffer' (controlled external inputs) during speculative > execution. This cross boundary access is then assign to parameter > 'LogEntryKey'. And the value of 'LogEntryKey' can be inferred by code: >=20 > CopyMem ( > (UINT8 *) &GaugeDataEx[Index], > (UINT8 *) &GaugeEntryExArray[LogEntryKey++], > sizeof (GAUGE_DATA_ENTRY_EX) > ); >=20 > One can observe which part of the content within 'GaugeEntryExArray' was > brought into cache to possibly reveal the value of 'LogEntryKey'. >=20 > Hence, this commit adds a AsmLfence() after the boundary/range checks of > 'CommBuffer' to prevent the speculative execution. >=20 > And there is 1 similar case for SMI handler SmmPerformanceHandler() as > well. This commit also handles it. >=20 > 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-firmw= are-speculative-execution-side-channel-mitigation >=20 > And the document at: > https://software.intel.com/security-software-guidance/api-app/sites/defau= lt/files/337879-analyzing-potential-bounds-Check-bypass-vuln > erabilities.pdf >=20 > 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(-) >=20 > diff --git a/MdeModulePkg/Library/SmmCorePerformanceLib/SmmCorePerformanc= eLib.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 @@ >=20 > SmmPerformanceHandlerEx(), SmmPerformanceHandler() will receive untrust= ed input and do basic validation. >=20 > -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 BS= D License > which accompanies this distribution. The full text of the license may b= e found at > @@ -538,6 +538,13 @@ SmmPerformanceHandlerEx ( > break; > } >=20 > + // > + // The AsmLfence() call here is to ensure the previous range/cont= ent > + // checks for the CommBuffer have been completed before calling > + // CopyMem(). > + // > + AsmLfence (); > + > GaugeEntryExArray =3D (GAUGE_DATA_ENTRY_EX *) (mGaugeData + 1); >=20 > for (Index =3D 0; Index < NumberOfEntries; Index++) { > @@ -650,6 +657,13 @@ SmmPerformanceHandler ( > break; > } >=20 > + // > + // The AsmLfence() call here is to ensure the previous range/cont= ent > + // checks for the CommBuffer have been completed before calling > + // CopyMem(). > + // > + AsmLfence (); > + > GaugeEntryExArray =3D (GAUGE_DATA_ENTRY_EX *) (mGaugeData + 1); >=20 > for (Index =3D 0; Index < NumberOfEntries; Index++) { > -- > 2.12.0.windows.1 >=20 > _______________________________________________ > edk2-devel mailing list > edk2-devel@lists.01.org > https://lists.01.org/mailman/listinfo/edk2-devel