From 810c635d6f40e85040033819f971d03d0f707c1a Mon Sep 17 00:00:00 2001 From: Hao Wu Date: Mon, 23 Jan 2017 14:38:43 +0800 Subject: [PATCH] ShellPkg: Refine type cast for pointer subtraction 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; Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Hao Wu Acked-by: Laszlo Ersek Reviewed-by: Ruiyu Ni Reviewed-by: Jaben Carsey --- ShellPkg/Application/Shell/ShellParametersProtocol.c | 6 +++--- ShellPkg/Library/UefiShellDebug1CommandsLib/DmpStore.c | 2 +- .../UefiShellDebug1CommandsLib/SmbiosView/SmbiosView.c | 4 ++-- ShellPkg/Library/UefiShellDriver1CommandsLib/Dh.c | 4 ++-- ShellPkg/Library/UefiShellLevel2CommandsLib/Cd.c | 4 ++-- 5 files changed, 10 insertions(+), 10 deletions(-) diff --git a/ShellPkg/Application/Shell/ShellParametersProtocol.c b/ShellPkg/Application/Shell/ShellParametersProtocol.c index 499915521a..8d76fb4be7 100644 --- a/ShellPkg/Application/Shell/ShellParametersProtocol.c +++ b/ShellPkg/Application/Shell/ShellParametersProtocol.c @@ -5,7 +5,7 @@ (C) Copyright 2016 Hewlett Packard Enterprise Development LP
Copyright (C) 2014, Red Hat, Inc. (C) Copyright 2013 Hewlett-Packard Development Company, L.P.
- 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 @@ -1034,9 +1034,9 @@ UpdateStdInStdOutStdErr( StrnCpyS(CommandLineCopy, StrSize(CommandLineCopy)/sizeof(CHAR16), NewCommandLine, StrLen(NewCommandLine)); if (FirstLocation != CommandLineCopy + StrLen(CommandLineCopy) - && ((UINTN)(FirstLocation - CommandLineCopy) < StrLen(NewCommandLine)) + && (((UINTN)FirstLocation - (UINTN)CommandLineCopy)/sizeof(CHAR16) < StrLen(NewCommandLine)) ){ - *(NewCommandLine + (UINTN)(FirstLocation - CommandLineCopy)) = CHAR_NULL; + *(NewCommandLine + ((UINTN)FirstLocation - (UINTN)CommandLineCopy)/sizeof(CHAR16)) = CHAR_NULL; } if (!EFI_ERROR(Status)) { diff --git a/ShellPkg/Library/UefiShellDebug1CommandsLib/DmpStore.c b/ShellPkg/Library/UefiShellDebug1CommandsLib/DmpStore.c index 701ff7505f..23db54553f 100644 --- a/ShellPkg/Library/UefiShellDebug1CommandsLib/DmpStore.c +++ b/ShellPkg/Library/UefiShellDebug1CommandsLib/DmpStore.c @@ -364,7 +364,7 @@ AppendSingleVariableToFile ( // // Crc32 // - gBS->CalculateCrc32 (Buffer, (UINTN) (Ptr - Buffer), (UINT32 *) Ptr); + gBS->CalculateCrc32 (Buffer, (UINTN) Ptr - (UINTN) Buffer, (UINT32 *) Ptr); Status = ShellWriteFile (FileHandle, &BufferSize, Buffer); FreePool (Buffer); diff --git a/ShellPkg/Library/UefiShellDebug1CommandsLib/SmbiosView/SmbiosView.c b/ShellPkg/Library/UefiShellDebug1CommandsLib/SmbiosView/SmbiosView.c index 56b682aa60..a5b16fec08 100644 --- a/ShellPkg/Library/UefiShellDebug1CommandsLib/SmbiosView/SmbiosView.c +++ b/ShellPkg/Library/UefiShellDebug1CommandsLib/SmbiosView/SmbiosView.c @@ -2,7 +2,7 @@ Tools of clarify the content of the smbios table. (C) Copyright 2015 Hewlett-Packard Development Company, L.P.
- Copyright (c) 2005 - 2012, Intel Corporation. All rights reserved.
+ Copyright (c) 2005 - 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 @@ -700,7 +700,7 @@ CalculateSmbios64BitStructureCountAndLength ( // // Length = Next structure head - this structure head // - (*Smbios64TableLength) += (UINTN) (Smbios.Raw - Raw); + (*Smbios64TableLength) += ((UINTN) Smbios.Raw - (UINTN) Raw); if ((*Smbios64TableLength) > Smbios64EntryPoint->TableMaximumSize) { // // The actual table length exceeds maximum table size, diff --git a/ShellPkg/Library/UefiShellDriver1CommandsLib/Dh.c b/ShellPkg/Library/UefiShellDriver1CommandsLib/Dh.c index d17a29d86f..0bcee9245c 100644 --- a/ShellPkg/Library/UefiShellDriver1CommandsLib/Dh.c +++ b/ShellPkg/Library/UefiShellDriver1CommandsLib/Dh.c @@ -75,7 +75,7 @@ IsValidGuidString( ) { Walker++; } else { - if (*Walker == L'-' && (UINTN)(Walker - PrevWalker) == mGuidDataLen[Index]) { + if (*Walker == L'-' && (((UINTN)Walker - (UINTN)PrevWalker) / sizeof (CHAR16)) == mGuidDataLen[Index]) { Walker++; PrevWalker = Walker; Index++; @@ -85,7 +85,7 @@ IsValidGuidString( } } - if ((UINTN)(Walker - PrevWalker) == mGuidDataLen[Index]) { + if ((((UINTN)Walker - (UINTN)PrevWalker) / sizeof (CHAR16)) == mGuidDataLen[Index]) { return TRUE; } else { return FALSE; diff --git a/ShellPkg/Library/UefiShellLevel2CommandsLib/Cd.c b/ShellPkg/Library/UefiShellLevel2CommandsLib/Cd.c index dd4a740354..9ae81763f7 100644 --- a/ShellPkg/Library/UefiShellLevel2CommandsLib/Cd.c +++ b/ShellPkg/Library/UefiShellLevel2CommandsLib/Cd.c @@ -99,10 +99,10 @@ IsCurrentFileSystem ( Splitter2 = StrStr (Cwd, L":"); - if ((UINTN) (Splitter1 - FullPath) != (UINTN) (Splitter2 - Cwd)) { + if (((UINTN) Splitter1 - (UINTN) FullPath) != ((UINTN) Splitter2 - (UINTN) Cwd)) { return FALSE; } else { - if (StrniCmp (FullPath, Cwd, (UINTN) (Splitter1 - FullPath)) == NULL) { + if (StrniCmp (FullPath, Cwd, ((UINTN) Splitter1 - (UINTN) FullPath) / sizeof (CHAR16)) == NULL) { return TRUE; } else { return FALSE; -- 2.39.2