From nobody Wed Dec 25 13:55:43 2024 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; spf=none (zoho.com: 198.145.21.10 is neither permitted nor denied by domain of lists.01.org) smtp.mailfrom=edk2-devel-bounces@lists.01.org Return-Path: Received: from ml01.01.org (ml01.01.org [198.145.21.10]) by mx.zohomail.com with SMTPS id 1507641904712382.9230421446498; Tue, 10 Oct 2017 06:25:04 -0700 (PDT) Received: from [127.0.0.1] (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id CAF5721DF9690; Tue, 10 Oct 2017 06:21:34 -0700 (PDT) Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) (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 CB0B221F3C1B9 for ; Tue, 10 Oct 2017 06:21:33 -0700 (PDT) Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 11A60E0759; Tue, 10 Oct 2017 13:25:01 +0000 (UTC) Received: from lacos-laptop-7.usersys.redhat.com (ovpn-120-87.rdu2.redhat.com [10.10.120.87]) by smtp.corp.redhat.com (Postfix) with ESMTP id 1547B6C429; Tue, 10 Oct 2017 13:24:58 +0000 (UTC) X-Original-To: edk2-devel@lists.01.org Received-SPF: none (zoho.com: 198.145.21.10 is neither permitted nor denied by domain of lists.01.org) client-ip=198.145.21.10; envelope-from=edk2-devel-bounces@lists.01.org; helo=ml01.01.org; Received-SPF: Pass (sender SPF authorized) identity=mailfrom; client-ip=209.132.183.28; helo=mx1.redhat.com; envelope-from=lersek@redhat.com; receiver=edk2-devel@lists.01.org DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 11A60E0759 Authentication-Results: ext-mx10.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx10.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=lersek@redhat.com From: Laszlo Ersek To: edk2-devel-01 Date: Tue, 10 Oct 2017 15:24:43 +0200 Message-Id: <20171010132443.11383-1-lersek@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Tue, 10 Oct 2017 13:25:01 +0000 (UTC) Subject: [edk2] [PATCH] MdeModulePkg/Variable/RuntimeDxe: delete & lock MOR in the absence of SMM X-BeenThere: edk2-devel@lists.01.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: EDK II Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Jiewen Yao , Eric Dong , Star Zeng MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Errors-To: edk2-devel-bounces@lists.01.org Sender: "edk2-devel" X-ZohoMail: RSF_4 Z_629925259 SPT_0 Content-Type: text/plain; charset="utf-8" VariableRuntimeDxe deletes and locks the MorLock variable in MorLockInit(), with the argument that any protection provided by MorLock can be circumvented if MorLock can be overwritten by unprivileged code (i.e., outside of SMM). Extend the argument and the logic to the MOR variable, which is supposed to be protected by MorLock. This change was suggested by Star; it is inspired by earlier VariableSmm commit fda8f631edbb ("MdeModulePkg/Variable/RuntimeDxe: delete and lock OS-created MOR variable", 2017-10-03). Cc: Eric Dong Cc: Jiewen Yao Cc: Star Zeng Suggested-by: Star Zeng Contributed-under: TianoCore Contribution Agreement 1.1 Signed-off-by: Laszlo Ersek --- Notes: Repo: https://github.com/lersek/edk2.git Branch: del_and_lock_mor_without_smm MdeModulePkg/Universal/Variable/RuntimeDxe/TcgMorLockDxe.c | 24 ++++++++++= ++++++++++ 1 file changed, 24 insertions(+) diff --git a/MdeModulePkg/Universal/Variable/RuntimeDxe/TcgMorLockDxe.c b/M= deModulePkg/Universal/Variable/RuntimeDxe/TcgMorLockDxe.c index 7142e2da2073..1610c7aa0706 100644 --- a/MdeModulePkg/Universal/Variable/RuntimeDxe/TcgMorLockDxe.c +++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/TcgMorLockDxe.c @@ -69,29 +69,53 @@ EFI_STATUS MorLockInit ( VOID ) { // // Always clear variable to report unsupported to OS. // The reason is that the DXE version is not proper to provide *protecti= on*. // BIOS should use SMM version variable driver to provide such capabilit= y. // VariableServiceSetVariable ( MEMORY_OVERWRITE_REQUEST_CONTROL_LOCK_NAME, &gEfiMemoryOverwriteRequestControlLockGuid, EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARI= ABLE_RUNTIME_ACCESS, 0, NULL ); =20 // // Need set this variable to be read-only to prevent other module set it. // VariableLockRequestToLock (&mVariableLock, MEMORY_OVERWRITE_REQUEST_CONT= ROL_LOCK_NAME, &gEfiMemoryOverwriteRequestControlLockGuid); + + // + // The MOR variable can effectively improve platform security only when = the + // MorLock variable protects the MOR variable. In turn MorLock cannot be= made + // secure without SMM support in the platform firmware (see above). + // + // Thus, delete the MOR variable, should it exist for any reason (some O= Ses + // are known to create MOR unintentionally, in an attempt to set it), th= en + // also lock the MOR variable, in order to prevent other modules from + // creating it. + // + VariableServiceSetVariable ( + MEMORY_OVERWRITE_REQUEST_VARIABLE_NAME, + &gEfiMemoryOverwriteControlDataGuid, + 0, // Attributes + 0, // DataSize + NULL // Data + ); + VariableLockRequestToLock ( + &mVariableLock, + MEMORY_OVERWRITE_REQUEST_VARIABLE_NAME, + &gEfiMemoryOverwriteControlDataGuid + ); + return EFI_SUCCESS; } =20 /** Delayed initialization for MOR Control Lock at EndOfDxe. =20 This function performs any operations queued by MorLockInit(). **/ --=20 2.14.1.3.gb7cf6e02401b _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel