From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: 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 A0C978214F for ; Fri, 24 Feb 2017 20:05:22 -0800 (PST) Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by orsmga104.jf.intel.com with ESMTP; 24 Feb 2017 20:05:22 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.35,202,1484035200"; d="scan'208";a="229518332" Received: from shwdeopenpsi014.ccr.corp.intel.com ([10.239.9.13]) by fmsmga004.fm.intel.com with ESMTP; 24 Feb 2017 20:05:21 -0800 From: Hao Wu To: edk2-devel@lists.01.org Cc: Hao Wu , Qin Long , Ting Ye Date: Sat, 25 Feb 2017 12:05:10 +0800 Message-Id: <1487995514-7628-3-git-send-email-hao.a.wu@intel.com> X-Mailer: git-send-email 1.9.5.msysgit.0 In-Reply-To: <1487995514-7628-1-git-send-email-hao.a.wu@intel.com> References: <1487995514-7628-1-git-send-email-hao.a.wu@intel.com> Subject: [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: Sat, 25 Feb 2017 04:05:22 -0000 For pointer subtraction, the result is of type "ptrdiff_t". According to the C11 standard (Committee Draft - April 12, 2011): "When two pointers are subtracted, both shall point to elements of the same array object, or one past the last element of the array object; the result is the difference of the subscripts of the two array elements. The size of the result is implementation-defined, and its type (a signed integer type) is ptrdiff_t defined in the header. If the result is not representable in an object of that type, the behavior is undefined." In our codes, there are cases that the pointer subtraction is not performed by pointers to elements of the same array object. This might lead to potential issues, since the behavior is undefined according to C11 standard. Also, since the size of type "ptrdiff_t" is implementation-defined. Some static code checkers may warn that the pointer subtraction might underflow first and then being cast to a bigger size. For example: UINT8 *Ptr1, *Ptr2; UINTN PtrDiff; ... PtrDiff = (UINTN) (Ptr1 - Ptr2); The commit will refine the pointer subtraction expressions by casting each pointer to UINTN first and then perform the subtraction: PtrDiff = (UINTN) Ptr1 - (UINTN) Ptr2; 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(-) 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. -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; - StartOffset = (UINTN) ((UINT8 *)Buffer - mRTPageTable->DataAreaBase); + StartOffset = (UINTN)Buffer - (UINTN)mRTPageTable->DataAreaBase; StartPageIndex = RT_SIZE_TO_PAGES (mRTPageTable->Pages[RT_SIZE_TO_PAGES(StartOffset)].StartPageOffset); while (StartPageIndex < mRTPageTable->PageCount) { @@ -403,7 +403,7 @@ void *realloc (void *ptr, size_t size) // // Get Original Size of ptr // - StartOffset = (UINTN) ((UINT8 *)ptr - mRTPageTable->DataAreaBase); + StartOffset = (UINTN)ptr - (UINTN)mRTPageTable->DataAreaBase; StartPageIndex = RT_SIZE_TO_PAGES (mRTPageTable->Pages[RT_SIZE_TO_PAGES (StartOffset)].StartPageOffset); PageCount = 0; while (StartPageIndex < mRTPageTable->PageCount) { -- 1.9.5.msysgit.0