Re: [PATCH v2 1/1] MdePkg: Refine casting expression result to bigger size

["Gao, Liming" <liming.gao@intel.com>]

Hao:
  For PCILIB_TO_COMMON_ADDRESS, we can't assume its usage in the consumer code. There may be some usage in other projects. So, I suggest to provide the safe fix. 

Thanks
Liming
>-----Original Message-----
>From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of Wu,
>Hao A
>Sent: Wednesday, January 25, 2017 8:26 AM
>To: Laszlo Ersek <lersek@redhat.com>
>Cc: edk2-devel@ml01.01.org
>Subject: Re: [edk2] [PATCH v2 1/1] MdePkg: Refine casting expression result
>to bigger size
>
>> -----Original Message-----
>> From: Laszlo Ersek [mailto:lersek@redhat.com]
>> Sent: Tuesday, January 24, 2017 5:54 PM
>> To: Wu, Hao A
>> Cc: edk2-devel@ml01.01.org
>> Subject: Re: [edk2] [PATCH v2 1/1] MdePkg: Refine casting expression result
>to
>> bigger size
>>
>> On 01/24/17 08:25, Hao Wu wrote:
>> > There are cases that the operands of an expression are all with rank less
>> > than UINT64/INT64 and the result of the expression is explicitly casted to
>> > UINT64/INT64 to fit the target size.
>> >
>> > An example will be:
>> > UINT32 a,b;
>> > // a and b can be any unsigned int type with rank less than UINT64, like
>> > // UINT8, UINT16, etc.
>> > UINT64 c;
>> > c = (UINT64) (a + b);
>> >
>> > Some static code checkers may warn that the expression result might
>> > overflow within the rank of "int" (integer promotions) and the result is
>> > then cast to a bigger size.
>> >
>> > The commit refines codes by the following rules:
>> > 1). When the expression will not overflow within the rank of "int", remove
>> > the explicit type casts:
>> > c = a + b;
>> >
>> > 2). When the expression is possible to overflow the range of unsigned int/
>> > int:
>> > c = (UINT64)a + b;
>> >
>> > Contributed-under: TianoCore Contribution Agreement 1.0
>> > Signed-off-by: Hao Wu <hao.a.wu@intel.com>
>> > ---
>> >  MdePkg/Library/BaseLib/String.c                              |  4 ++--
>> >  MdePkg/Library/BasePeCoffLib/BasePeCoff.c                    | 12 +++++-------
>> >  MdePkg/Library/BaseS3PciLib/S3PciLib.c                       |  4 ++--
>> >  MdePkg/Library/SmmMemoryAllocationLib/MemoryAllocationLib.c  |  4
>++--
>> >  MdePkg/Library/UefiMemoryAllocationLib/MemoryAllocationLib.c |  4
>++--
>> >  5 files changed, 13 insertions(+), 15 deletions(-)
>> >
>> > diff --git a/MdePkg/Library/BaseLib/String.c
>> b/MdePkg/Library/BaseLib/String.c
>> > index e84bf50..4151e0e 100644
>> > --- a/MdePkg/Library/BaseLib/String.c
>> > +++ b/MdePkg/Library/BaseLib/String.c
>> > @@ -586,7 +586,7 @@ InternalHexCharToUintn (
>> >      return Char - L'0';
>> >    }
>> >
>> > -  return (UINTN) (10 + InternalCharToUpper (Char) - L'A');
>> > +  return (10 + InternalCharToUpper (Char) - L'A');
>> >  }
>> >
>> >  /**
>> > @@ -1211,7 +1211,7 @@ InternalAsciiHexCharToUintn (
>> >      return Char - '0';
>> >    }
>> >
>> > -  return (UINTN) (10 + InternalBaseLibAsciiToUpper (Char) - 'A');
>> > +  return (10 + InternalBaseLibAsciiToUpper (Char) - 'A');
>> >  }
>> >
>> >
>> > diff --git a/MdePkg/Library/BasePeCoffLib/BasePeCoff.c
>> b/MdePkg/Library/BasePeCoffLib/BasePeCoff.c
>> > index 33cad23..8d1daba 100644
>> > --- a/MdePkg/Library/BasePeCoffLib/BasePeCoff.c
>> > +++ b/MdePkg/Library/BasePeCoffLib/BasePeCoff.c
>> > @@ -15,7 +15,7 @@
>> >    PeCoffLoaderGetPeHeader() routine will do basic check for PE/COFF
>header.
>> >    PeCoffLoaderGetImageInfo() routine will do basic check for whole
>PE/COFF
>> image.
>> >
>> > -  Copyright (c) 2006 - 2014, Intel Corporation. All rights reserved.<BR>
>> > +  Copyright (c) 2006 - 2017, Intel Corporation. All rights reserved.<BR>
>> >    Portions copyright (c) 2008 - 2009, Apple Inc. All rights reserved.<BR>
>> >    This program and the accompanying materials
>> >    are licensed and made available under the terms and conditions of the
>BSD
>> License
>> > @@ -703,12 +703,10 @@ PeCoffLoaderGetImageInfo (
>> >        //
>> >        DebugDirectoryEntryFileOffset = 0;
>> >
>> > -      SectionHeaderOffset = (UINTN)(
>> > -                               ImageContext->PeCoffHeaderOffset +
>> > -                               sizeof (UINT32) +
>> > -                               sizeof (EFI_IMAGE_FILE_HEADER) +
>> > -                               Hdr.Pe32->FileHeader.SizeOfOptionalHeader
>> > -                               );
>> > +      SectionHeaderOffset = ImageContext->PeCoffHeaderOffset +
>> > +                            sizeof (UINT32) +
>> > +                            sizeof (EFI_IMAGE_FILE_HEADER) +
>> > +                            Hdr.Pe32->FileHeader.SizeOfOptionalHeader;
>> >
>> >        for (Index = 0; Index < Hdr.Pe32->FileHeader.NumberOfSections;
>Index++)
>> {
>> >          //
>> > diff --git a/MdePkg/Library/BaseS3PciLib/S3PciLib.c
>> b/MdePkg/Library/BaseS3PciLib/S3PciLib.c
>> > index e29f7fe..27342b0 100644
>> > --- a/MdePkg/Library/BaseS3PciLib/S3PciLib.c
>> > +++ b/MdePkg/Library/BaseS3PciLib/S3PciLib.c
>> > @@ -3,7 +3,7 @@
>> >    the PCI operations to be replayed during an S3 resume. This library class
>> >    maps directly on top of the PciLib class.
>> >
>> > -  Copyright (c) 2006 - 2012, Intel Corporation. All rights reserved.<BR>
>> > +  Copyright (c) 2006 - 2017, Intel Corporation. All rights reserved.<BR>
>> >
>> >    This program and the accompanying materials
>> >    are licensed and made available under the terms and conditions
>> > @@ -25,7 +25,7 @@
>> >  #include <Library/S3PciLib.h>
>> >
>> >  #define PCILIB_TO_COMMON_ADDRESS(Address) \
>> > -        ((UINT64) ((((UINTN) ((Address>>20) & 0xff)) << 24) + (((UINTN)
>> ((Address>>15) & 0x1f)) << 16) + (((UINTN) ((Address>>12) & 0x07)) << 8) +
>> ((UINTN) (Address & 0xfff ))))
>> > +        ((((UINTN) ((Address>>20) & 0xff)) << 24) + (((UINTN)
>((Address>>15) &
>> 0x1f)) << 16) + (((UINTN) ((Address>>12) & 0x07)) << 8) + ((UINTN)
>(Address &
>> 0xfff )))
>> >
>> >  /**
>> >    Saves a PCI configuration value to the boot script.
>>
>> I think this change is potentially unsafe, without auditing all uses of
>> PCILIB_TO_COMMON_ADDRESS(). In a 32-bit build, the type of the result
>> will no longer be UINT64 but UINT32, and that can cause problems in
>> several contexts. For example:
>>
>> - as an operand to the sizeof operator
>> - when it's being relied upon to cause conversion to UINT64, for example
>> another (UINT32) operand could be added to it
>> - when it is passed through a variable argument list
>>
>> It might be safe, but there's no way to tell without auditing all the
>> call sites. So let me see...
>>
>> Apparently this macro is only passed to S3BootScriptSavePciCfgWrite() as
>> second argument, within the same file, and that argument is covered by
>> the function prototype explicitly, with type UINT64. So the change
>> should be safe.
>>
>
>Thanks for the checking. I did search the whole edk2 repository for the
>reference of "PCILIB_TO_COMMON_ADDRESS" and it is only comsumed by
>the
>function you mentioned.
>
>> (I see the same macro definition and kind of invocation in
>> "QuarkPlatformPkg/Acpi/DxeSmm/AcpiSmm/AcpiSmmPlatform.c"; I didn't
>try
>> to audit that file.)
>>
>> The rest looks okay too.
>>
>> Reviewed-by: Laszlo Ersek <lersek@redhat.com>
>>
>
>Many thanks for the feedbacks and the effort for reviewing the patch.
>
>> (If you go ahead and submit a 30-part series that does this kind of
>> fixup all over the tree, please don't expect me to review it all -- I'm
>> okay reviewing OvmfPkg and ArmVirtPkg changes, but I can't take on the
>> rest. This kind of patch cannot be reviewed without consulting a really
>> wide context.)
>>
>
>I am thinking if the package level patch contains too many changes, I
>might break it into multiple module-level patches and include module
>owners/experts to help reviewing them.
>
>Best Regards,
>Hao Wu
>
>> Thanks
>> Laszlo
>>
>>
>> > diff --git
>> a/MdePkg/Library/SmmMemoryAllocationLib/MemoryAllocationLib.c
>> b/MdePkg/Library/SmmMemoryAllocationLib/MemoryAllocationLib.c
>> > index 937165a..592cced 100644
>> > --- a/MdePkg/Library/SmmMemoryAllocationLib/MemoryAllocationLib.c
>> > +++ b/MdePkg/Library/SmmMemoryAllocationLib/MemoryAllocationLib.c
>> > @@ -12,7 +12,7 @@
>> >    allocation for the Reserved memory types are not supported and will
>> always
>> >    return NULL.
>> >
>> > -  Copyright (c) 2006 - 2015, Intel Corporation. All rights reserved.<BR>
>> > +  Copyright (c) 2006 - 2017, Intel Corporation. All rights reserved.<BR>
>> >    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
>> > @@ -343,7 +343,7 @@ InternalAllocateAlignedPages (
>> >        Status = gSmst->SmmFreePages (Memory, UnalignedPages);
>> >        ASSERT_EFI_ERROR (Status);
>> >      }
>> > -    Memory         = (EFI_PHYSICAL_ADDRESS) (AlignedMemory +
>> EFI_PAGES_TO_SIZE (Pages));
>> > +    Memory         = AlignedMemory + EFI_PAGES_TO_SIZE (Pages);
>> >      UnalignedPages = RealPages - Pages - UnalignedPages;
>> >      if (UnalignedPages > 0) {
>> >        //
>> > diff --git
>a/MdePkg/Library/UefiMemoryAllocationLib/MemoryAllocationLib.c
>> b/MdePkg/Library/UefiMemoryAllocationLib/MemoryAllocationLib.c
>> > index 3da5e211..3bd3aef 100644
>> > --- a/MdePkg/Library/UefiMemoryAllocationLib/MemoryAllocationLib.c
>> > +++ b/MdePkg/Library/UefiMemoryAllocationLib/MemoryAllocationLib.c
>> > @@ -2,7 +2,7 @@
>> >    Support routines for memory allocation routines based
>> >    on boot services for Dxe phase drivers.
>> >
>> > -  Copyright (c) 2006 - 2015, Intel Corporation. All rights reserved.<BR>
>> > +  Copyright (c) 2006 - 2017, Intel Corporation. All rights reserved.<BR>
>> >    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
>> > @@ -216,7 +216,7 @@ InternalAllocateAlignedPages (
>> >        Status = gBS->FreePages (Memory, UnalignedPages);
>> >        ASSERT_EFI_ERROR (Status);
>> >      }
>> > -    Memory         = (EFI_PHYSICAL_ADDRESS) (AlignedMemory +
>> EFI_PAGES_TO_SIZE (Pages));
>> > +    Memory         = AlignedMemory + EFI_PAGES_TO_SIZE (Pages);
>> >      UnalignedPages = RealPages - Pages - UnalignedPages;
>> >      if (UnalignedPages > 0) {
>> >        //
>> >
>
>_______________________________________________
>edk2-devel mailing list
>edk2-devel@lists.01.org
>https://lists.01.org/mailman/listinfo/edk2-devel