From nobody Sat Nov 2 10:37:04 2024 Delivered-To: importer@patchew.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; Authentication-Results: mx.zoho.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 1491874225389723.5333459141974; Mon, 10 Apr 2017 18:30:25 -0700 (PDT) Received: from [127.0.0.1] (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id B411E21A04822; Mon, 10 Apr 2017 18:29:52 -0700 (PDT) Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) (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 6906D21A04802 for ; Mon, 10 Apr 2017 18:29:51 -0700 (PDT) Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga105.fm.intel.com with ESMTP; 10 Apr 2017 18:29:50 -0700 Received: from shwdeopenpsi014.ccr.corp.intel.com ([10.239.9.13]) by orsmga002.jf.intel.com with ESMTP; 10 Apr 2017 18:29:49 -0700 X-Original-To: edk2-devel@lists.01.org X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.37,184,1488873600"; d="scan'208";a="72328869" From: Hao Wu To: edk2-devel@lists.01.org, lersek@redhat.com, guoheyi@huawei.com Date: Tue, 11 Apr 2017 09:29:45 +0800 Message-Id: <20170411012945.16788-1-hao.a.wu@intel.com> X-Mailer: git-send-email 2.12.0.windows.1 Subject: [edk2] [PATCH v2] MdeModulePkg/ScsiDiskDxe: Fix undefined behavior in signed left shift 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: Hao Wu , Feng Tian 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" In function GetMediaInfo(), the following expression: ScsiDiskDevice->BlkIo.Media->LastBlock =3D (Capacity10->LastLba3 << 24) | (Capacity10->LastLba2 << 16) | (Capacity10->LastLba1 << 8) | Capacity10->LastLba0; will involve undefined behavior in signed left shift operations. Since Capacity10->LastLbaX is of type UINT8, and ScsiDiskDevice->BlkIo.Media->LastBlock is of type UINT64. Therefore, Capacity10->LastLbaX will be promoted to int (32 bits, signed) first, and then perform the left shift operation. According to the C11 spec, Section 6.5.7: 4 The result of E1 << E2 is E1 left-shifted E2 bit positions; vacated bits are filled with zeros. If E1 has an unsigned type, the value of the result is E1 * 2^E2 , reduced modulo one more than the maximum value representable in the result type. If E1 has a signed type and nonnegative value, and E1 * 2^E2 is representable in the result type, then that is the resulting value; otherwise, the behavior is undefined. So if bit 7 of Capacity10->LastLba3 is 1, (Capacity10->LastLba3 << 24) will be out of the range within int type. The undefined behavior of the signed left shift will lead to a potential of setting the high 32 bits of ScsiDiskDevice->BlkIo.Media->LastBlock to 1 during the cast from type int to type UINT64. This commit will add an explicit UINT32 type cast for Capacity10->LastLba3 to resolve this issue. Cc: Feng Tian Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Hao Wu Reviewed-by: Feng Tian Reviewed-by: Laszlo Ersek --- MdeModulePkg/Bus/Scsi/ScsiDiskDxe/ScsiDisk.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/MdeModulePkg/Bus/Scsi/ScsiDiskDxe/ScsiDisk.c b/MdeModulePkg/Bu= s/Scsi/ScsiDiskDxe/ScsiDisk.c index b5eff25b9b..2289f20152 100644 --- a/MdeModulePkg/Bus/Scsi/ScsiDiskDxe/ScsiDisk.c +++ b/MdeModulePkg/Bus/Scsi/ScsiDiskDxe/ScsiDisk.c @@ -1,7 +1,7 @@ /** @file SCSI disk driver that layers on every SCSI IO protocol in the system. =20 -Copyright (c) 2006 - 2016, Intel Corporation. All rights reserved.
+Copyright (c) 2006 - 2017, 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 @@ -2754,7 +2754,7 @@ GetMediaInfo ( UINT8 *Ptr; =20 if (!ScsiDiskDevice->Cdb16Byte) { - ScsiDiskDevice->BlkIo.Media->LastBlock =3D (Capacity10->LastLba3 << 2= 4) | + ScsiDiskDevice->BlkIo.Media->LastBlock =3D ((UINT32) Capacity10->Last= Lba3 << 24) | (Capacity10->LastLba2 << 16)= | (Capacity10->LastLba1 << 8) = | Capacity10->LastLba0; --=20 2.12.0.windows.1 _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel