From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: 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 A20DB821B6 for ; Sun, 26 Feb 2017 18:23:58 -0800 (PST) Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga104.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 26 Feb 2017 18:23:58 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.35,211,1484035200"; d="scan'208";a="70461789" Received: from fmsmsx108.amr.corp.intel.com ([10.18.124.206]) by fmsmga006.fm.intel.com with ESMTP; 26 Feb 2017 18:23:58 -0800 Received: from fmsmsx156.amr.corp.intel.com (10.18.116.74) by FMSMSX108.amr.corp.intel.com (10.18.124.206) with Microsoft SMTP Server (TLS) id 14.3.248.2; Sun, 26 Feb 2017 18:23:58 -0800 Received: from shsmsx104.ccr.corp.intel.com (10.239.4.70) by fmsmsx156.amr.corp.intel.com (10.18.116.74) with Microsoft SMTP Server (TLS) id 14.3.248.2; Sun, 26 Feb 2017 18:23:57 -0800 Received: from shsmsx103.ccr.corp.intel.com ([169.254.4.20]) by SHSMSX104.ccr.corp.intel.com ([10.239.4.70]) with mapi id 14.03.0248.002; Mon, 27 Feb 2017 10:23:55 +0800 From: "Long, Qin" To: "Wu, Hao A" , "edk2-devel@lists.01.org" CC: "Wu, Hao A" , "Ye, Ting" Thread-Topic: [edk2] [PATCH v3 2/6] CryptoPkg: Refine type cast for pointer subtraction Thread-Index: AQHSjxxnb2/JmmDoNEmZsAThGCRezaF8Irqg Date: Mon, 27 Feb 2017 02:23:54 +0000 Message-ID: References: <1487995514-7628-1-git-send-email-hao.a.wu@intel.com> <1487995514-7628-3-git-send-email-hao.a.wu@intel.com> In-Reply-To: <1487995514-7628-3-git-send-email-hao.a.wu@intel.com> Accept-Language: zh-CN, en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.239.127.40] MIME-Version: 1.0 Subject: Re: [PATCH v3 2/6] CryptoPkg: Refine type cast for pointer subtraction X-BeenThere: edk2-devel@lists.01.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: EDK II Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 27 Feb 2017 02:23:58 -0000 Content-Language: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Reviewed-by: Qin Long > -----Original Message----- > From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of > Hao Wu > Sent: Saturday, February 25, 2017 12:05 PM > To: edk2-devel@lists.01.org > Cc: Wu, Hao A; Ye, Ting; Long, Qin > Subject: [edk2] [PATCH v3 2/6] CryptoPkg: Refine type cast for pointer > subtraction >=20 > For pointer subtraction, the result is of type "ptrdiff_t". According to = the C11 > standard (Committee Draft - April 12, 2011): >=20 > "When two pointers are subtracted, both shall point to elements of the sa= me > array object, or one past the last element of the array object; the resul= t is the > difference of the subscripts of the two array elements. The size of the r= esult > is implementation-defined, and its type (a signed integer type) is ptrdif= f_t > defined in the header. If the result is not representable in a= n > object of that type, the behavior is undefined." >=20 > In our codes, there are cases that the pointer subtraction is not perform= ed > by pointers to elements of the same array object. This might lead to pote= ntial > issues, since the behavior is undefined according to C11 standard. >=20 > Also, since the size of type "ptrdiff_t" is implementation-defined. Some > static code checkers may warn that the pointer subtraction might underflo= w > first and then being cast to a bigger size. For example: >=20 > UINT8 *Ptr1, *Ptr2; > UINTN PtrDiff; > ... > PtrDiff =3D (UINTN) (Ptr1 - Ptr2); >=20 > The commit will refine the pointer subtraction expressions by casting eac= h > pointer to UINTN first and then perform the subtraction: >=20 > PtrDiff =3D (UINTN) Ptr1 - (UINTN) Ptr2; >=20 > Cc: Qin Long > Cc: Ting Ye > Contributed-under: TianoCore Contribution Agreement 1.0 > Signed-off-by: Hao Wu > Acked-by: Laszlo Ersek > --- > CryptoPkg/Library/BaseCryptLib/SysCall/RuntimeMemAllocation.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) >=20 > diff --git a/CryptoPkg/Library/BaseCryptLib/SysCall/RuntimeMemAllocation.= c > b/CryptoPkg/Library/BaseCryptLib/SysCall/RuntimeMemAllocation.c > index 19c30dc..feaa371 100644 > --- a/CryptoPkg/Library/BaseCryptLib/SysCall/RuntimeMemAllocation.c > +++ b/CryptoPkg/Library/BaseCryptLib/SysCall/RuntimeMemAllocation.c > @@ -2,7 +2,7 @@ > Light-weight Memory Management Routines for OpenSSL-based Crypto > Library at Runtime Phase. >=20 > -Copyright (c) 2009 - 2016, Intel Corporation. All rights reserved.
> +Copyright (c) 2009 - 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 > @@ -282,7 +282,7 @@ RuntimeFreeMem ( > UINTN StartOffset; > UINTN StartPageIndex; >=20 > - StartOffset =3D (UINTN) ((UINT8 *)Buffer - mRTPageTable->DataAreaBa= se); > + StartOffset =3D (UINTN)Buffer - (UINTN)mRTPageTable->DataAreaBase; > StartPageIndex =3D RT_SIZE_TO_PAGES (mRTPageTable- > >Pages[RT_SIZE_TO_PAGES(StartOffset)].StartPageOffset); >=20 > while (StartPageIndex < mRTPageTable->PageCount) { @@ -403,7 +403,7 > @@ void *realloc (void *ptr, size_t size) > // > // Get Original Size of ptr > // > - StartOffset =3D (UINTN) ((UINT8 *)ptr - mRTPageTable->DataAreaBase)= ; > + StartOffset =3D (UINTN)ptr - (UINTN)mRTPageTable->DataAreaBase; > StartPageIndex =3D RT_SIZE_TO_PAGES (mRTPageTable- > >Pages[RT_SIZE_TO_PAGES (StartOffset)].StartPageOffset); > PageCount =3D 0; > while (StartPageIndex < mRTPageTable->PageCount) { > -- > 1.9.5.msysgit.0 >=20 > _______________________________________________ > edk2-devel mailing list > edk2-devel@lists.01.org > https://lists.01.org/mailman/listinfo/edk2-devel