From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) (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 22C2C81C73 for ; Tue, 24 Jan 2017 21:28:26 -0800 (PST) Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga102.jf.intel.com with ESMTP; 24 Jan 2017 21:28:25 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.33,282,1477983600"; d="scan'208";a="1117468628" Received: from shwdeopenpsi014.ccr.corp.intel.com ([10.239.9.13]) by fmsmga002.fm.intel.com with ESMTP; 24 Jan 2017 21:28:24 -0800 From: Hao Wu To: edk2-devel@lists.01.org Cc: Hao Wu , Laszlo Ersek Date: Wed, 25 Jan 2017 13:28:20 +0800 Message-Id: <1485322101-17128-1-git-send-email-hao.a.wu@intel.com> X-Mailer: git-send-email 1.9.5.msysgit.0 Subject: [PATCH v2 0/6] 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: Wed, 25 Jan 2017 05:28:26 -0000 Please note that this patch is maily for feedback collection and only the MdeModulePkg part of the series is sent out firstly. V2 refines the commit messages: 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; V1: For pointer subtraction, the result is of type "ptrdiff_t". According to the C11 spec, ptrdiff_t is a signed integer type but its size is implementation-defined. There are cases that the result of pointer subtraction is type casted to UINTN, like: UINT8 *Ptr1, *Ptr2; UINTN PtrDiff; ... PtrDiff = (UINTN) (Ptr1 - Ptr2); Some static code checkers may warn that the pointer subtraction might overflow first and then the result is being cast to a bigger size. The series will cast each pointer to UINTN first and then perform the subtraction: PtrDiff = (UINTN) Ptr1 - (UINTN) Ptr2; Cc: Laszlo Ersek Hao Wu (6): MdeModulePkg: Refine type cast for pointer subtraction CryptoPkg: Refine type cast for pointer subtraction IntelFrameworkModulePkg: Refine type cast for pointer subtraction NetworkPkg: Refine type cast for pointer subtraction SecurityPkg: Refine type cast for pointer subtraction ShellPkg: Refine type cast for pointer subtraction CryptoPkg/Library/BaseCryptLib/SysCall/RuntimeMemAllocation.c | 6 +++--- IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyPci.c | 4 ++-- IntelFrameworkModulePkg/Library/GenericBdsLib/BdsBoot.c | 4 ++-- IntelFrameworkModulePkg/Library/GenericBdsLib/BdsConsole.c | 4 ++-- IntelFrameworkModulePkg/Library/GenericBdsLib/BdsMisc.c | 4 ++-- IntelFrameworkModulePkg/Library/LegacyBootManagerLib/LegacyBm.c | 4 ++-- IntelFrameworkModulePkg/Universal/BdsDxe/BootMaint/BootOption.c | 6 +++--- MdeModulePkg/Bus/Pci/PciBusDxe/PciOptionRomSupport.c | 4 ++-- MdeModulePkg/Include/Library/NetLib.h | 6 +++--- MdeModulePkg/Library/DxeCapsuleLibFmp/DxeCapsuleLib.c | 4 ++-- MdeModulePkg/Library/DxePrintLibPrint2Protocol/PrintLib.c | 2 +- MdeModulePkg/Library/FileExplorerLib/FileExplorer.c | 6 +++--- MdeModulePkg/Library/PiDxeS3BootScriptLib/BootScriptSave.c | 4 ++-- MdeModulePkg/Library/UefiBootManagerLib/BmLoadOption.c | 4 ++-- MdeModulePkg/Universal/DebugPortDxe/DebugPort.c | 4 ++-- MdeModulePkg/Universal/FaultTolerantWriteDxe/FaultTolerantWrite.c | 4 ++-- MdeModulePkg/Universal/HiiDatabaseDxe/Image.c | 4 ++-- MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.c | 10 +++++----- NetworkPkg/HttpDxe/HttpImpl.c | 6 +++--- SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c | 18 +++++++++--------- SecurityPkg/Library/DxeTpmMeasureBootLib/DxeTpmMeasureBootLib.c | 10 +++++----- SecurityPkg/Library/Tpm2CommandLib/Tpm2Help.c | 6 +++--- SecurityPkg/Tcg/Tcg2Dxe/MeasureBootPeCoff.c | 10 +++++----- SecurityPkg/Tcg/TrEEDxe/MeasureBootPeCoff.c | 10 +++++----- SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfigImpl.c | 14 +++++++------- ShellPkg/Application/Shell/ShellParametersProtocol.c | 6 +++--- ShellPkg/Library/UefiShellDebug1CommandsLib/DmpStore.c | 4 ++-- ShellPkg/Library/UefiShellDebug1CommandsLib/SmbiosView/SmbiosView.c | 4 ++-- ShellPkg/Library/UefiShellDriver1CommandsLib/Dh.c | 4 ++-- ShellPkg/Library/UefiShellLevel2CommandsLib/Cd.c | 6 +++--- 30 files changed, 91 insertions(+), 91 deletions(-) -- 1.9.5.msysgit.0