From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received-SPF: Pass (sender SPF authorized) identity=mailfrom; client-ip=192.55.52.120; helo=mga04.intel.com; envelope-from=liming.gao@intel.com; receiver=edk2-devel@lists.01.org Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) (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 CC26F21E1B773 for ; Wed, 27 Sep 2017 20:51:16 -0700 (PDT) Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga104.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 27 Sep 2017 20:54:30 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.42,448,1500966000"; d="scan'208";a="156951908" Received: from fmsmsx105.amr.corp.intel.com ([10.18.124.203]) by fmsmga006.fm.intel.com with ESMTP; 27 Sep 2017 20:54:30 -0700 Received: from fmsmsx121.amr.corp.intel.com (10.18.125.36) by FMSMSX105.amr.corp.intel.com (10.18.124.203) with Microsoft SMTP Server (TLS) id 14.3.319.2; Wed, 27 Sep 2017 20:54:30 -0700 Received: from shsmsx101.ccr.corp.intel.com (10.239.4.153) by fmsmsx121.amr.corp.intel.com (10.18.125.36) with Microsoft SMTP Server (TLS) id 14.3.319.2; Wed, 27 Sep 2017 20:54:30 -0700 Received: from shsmsx152.ccr.corp.intel.com ([169.254.6.93]) by SHSMSX101.ccr.corp.intel.com ([169.254.1.159]) with mapi id 14.03.0319.002; Thu, 28 Sep 2017 11:54:28 +0800 From: "Gao, Liming" To: "Wu, Hao A" , "edk2-devel@lists.01.org" CC: "Wu, Hao A" , Paolo Bonzini , "Dong, Eric" , "Zeng, Star" Thread-Topic: [edk2] [PATCH v2 5/6] MdeModulePkg/Crc32: Fix possible out of range left shift Thread-Index: AQHTMqVxiBnyPxfCE0ehM1ZlC2DggqLJtQjg Date: Thu, 28 Sep 2017 03:54:27 +0000 Message-ID: <4A89E2EF3DFEDB4C8BFDE51014F606A14E15EA8E@SHSMSX152.ccr.corp.intel.com> References: <20170921064617.2628-1-hao.a.wu@intel.com> <20170921064617.2628-6-hao.a.wu@intel.com> In-Reply-To: <20170921064617.2628-6-hao.a.wu@intel.com> Accept-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.239.127.40] MIME-Version: 1.0 Subject: Re: [PATCH v2 5/6] MdeModulePkg/Crc32: Fix possible out of range 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: , X-List-Received-Date: Thu, 28 Sep 2017 03:51:17 -0000 Content-Language: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Hao: I sent another patch to introduce CacluateCrc32() API in BaseLib. It will= update MdeModulePkg Crc32 to depend on BaseLib. And, BaseLib CacluateCrc32= () has no such logic. So, I think this patch is not necessary.=20 Thanks Liming >-----Original Message----- >From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of Hao >Wu >Sent: Thursday, September 21, 2017 2:46 PM >To: edk2-devel@lists.01.org >Cc: Wu, Hao A ; Paolo Bonzini ; >Dong, Eric ; Zeng, Star >Subject: [edk2] [PATCH v2 5/6] MdeModulePkg/Crc32: Fix possible out of >range left shift > >REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3D697 > >Within function ReverseBits(), left shift operations of 1 in the >following statements: >"(1 << Index)" and "(1 << (31 - Index))" > >will incur possible out of range left shift when Index is either 0 or >31, since "1 << 31" is possible to exceed the range of type 'int' >(signed). > >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. > >This commit uses '1U' instead of '1' to resolve this issue. > >Cc: Steven Shi >Cc: Star Zeng >Cc: Eric Dong >Cc: Paolo Bonzini >Contributed-under: TianoCore Contribution Agreement 1.1 >Signed-off-by: Hao Wu >--- > MdeModulePkg/Core/RuntimeDxe/Crc32.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > >diff --git a/MdeModulePkg/Core/RuntimeDxe/Crc32.c >b/MdeModulePkg/Core/RuntimeDxe/Crc32.c >index a6fe77fa34..2cd234b562 100644 >--- a/MdeModulePkg/Core/RuntimeDxe/Crc32.c >+++ b/MdeModulePkg/Core/RuntimeDxe/Crc32.c >@@ -7,7 +7,7 @@ > EFI Runtime Services Table are converted from physical address to > virtual addresses. This requires that the 32-bit CRC be recomputed. > >-Copyright (c) 2006 - 2008, 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 >@@ -79,8 +79,8 @@ ReverseBits ( > > NewValue =3D 0; > for (Index =3D 0; Index < 32; Index++) { >- if ((Value & (1 << Index)) !=3D 0) { >- NewValue =3D NewValue | (1 << (31 - Index)); >+ if ((Value & (1U << Index)) !=3D 0) { >+ NewValue =3D NewValue | (1U << (31 - Index)); > } > } > >-- >2.12.0.windows.1 > >_______________________________________________ >edk2-devel mailing list >edk2-devel@lists.01.org >https://lists.01.org/mailman/listinfo/edk2-devel