reactos/ntoskrnl/mm/pe.c

/*
 * COPYRIGHT:       See COPYING in the top level directory
 * PROJECT:         ReactOS kernel
 * FILE:            ntoskrnl/mm/pe.c
 * PURPOSE:         Loader for PE executables
 *
 * PROGRAMMERS:     KJK::Hyperion <hackbunny@reactos.com>
 */

/* INCLUDES *****************************************************************/

#include <ntoskrnl.h>

//#define NDEBUG
#include <internal/debug.h>

#include <reactos/exeformat.h>

#ifndef MAXULONG
#define MAXULONG ((ULONG)(~1))
#endif

static ULONG SectionCharacteristicsToProtect[16] =
{
    PAGE_NOACCESS,          /* 0 = NONE */
    PAGE_NOACCESS,          /* 1 = SHARED */
    PAGE_EXECUTE,           /* 2 = EXECUTABLE */
    PAGE_EXECUTE,           /* 3 = EXECUTABLE, SHARED */
    PAGE_READONLY,          /* 4 = READABLE */
    PAGE_READONLY,          /* 5 = READABLE, SHARED */
    PAGE_EXECUTE_READ,      /* 6 = READABLE, EXECUTABLE */
    PAGE_EXECUTE_READ,      /* 7 = READABLE, EXECUTABLE, SHARED */
    /*
     * FIXME? do we really need the WriteCopy field in segments? can't we use
     * PAGE_WRITECOPY here?
     */
    PAGE_READWRITE,         /* 8 = WRITABLE */
    PAGE_READWRITE,         /* 9 = WRITABLE, SHARED */
    PAGE_EXECUTE_READWRITE, /* 10 = WRITABLE, EXECUTABLE */
    PAGE_EXECUTE_READWRITE, /* 11 = WRITABLE, EXECUTABLE, SHARED */
    PAGE_READWRITE,         /* 12 = WRITABLE, READABLE */
    PAGE_READWRITE,         /* 13 = WRITABLE, READABLE, SHARED */
    PAGE_EXECUTE_READWRITE, /* 14 = WRITABLE, READABLE, EXECUTABLE */
    PAGE_EXECUTE_READWRITE, /* 15 = WRITABLE, READABLE, EXECUTABLE, SHARED */
};

/* TODO: Intsafe should be made into a library, as it's generally useful */
static __inline BOOLEAN Intsafe_CanAddULongPtr(IN ULONG_PTR Addend1, IN ULONG_PTR Addend2)
{
    return Addend1 <= (MAXULONG_PTR - Addend2);
}

#ifndef MAXLONGLONG
#define MAXLONGLONG ((LONGLONG)((~((ULONGLONG)0)) >> 1))
#endif

static __inline BOOLEAN Intsafe_CanAddLong64(IN LONG64 Addend1, IN LONG64 Addend2)
{
    return Addend1 <= (MAXLONGLONG - Addend2);
}

static __inline BOOLEAN Intsafe_CanAddULong32(IN ULONG Addend1, IN ULONG Addend2)
{
    return Addend1 <= (MAXULONG - Addend2);
}

static __inline BOOLEAN Intsafe_AddULong32(OUT PULONG Result, IN ULONG Addend1, IN ULONG Addend2)
{
    if(!Intsafe_CanAddULong32(Addend1, Addend2))
	return FALSE;

    *Result = Addend1 + Addend2;
    return TRUE;
}

static __inline BOOLEAN Intsafe_CanMulULong32(IN ULONG Factor1, IN ULONG Factor2)
{
    return Factor1 <= (MAXULONG / Factor2);
}

static __inline BOOLEAN Intsafe_CanOffsetPointer(IN CONST VOID * Pointer, IN SIZE_T Offset)
{
    /* FIXME: (PVOID)MAXULONG_PTR isn't necessarily a valid address */
    return Intsafe_CanAddULongPtr((ULONG_PTR)Pointer, Offset);
}

/* TODO: these are standard DDK/PSDK macros */
#ifndef RTL_FIELD_SIZE
#define RTL_FIELD_SIZE(TYPE_, FIELD_) (sizeof(((TYPE_ *)0)->FIELD_))
#endif

#ifndef RTL_SIZEOF_THROUGH_FIELD
#define RTL_SIZEOF_THROUGH_FIELD(TYPE_, FIELD_) \
 (FIELD_OFFSET(TYPE_, FIELD_) + RTL_FIELD_SIZE(TYPE_, FIELD_))
#endif

#ifndef RTL_CONTAINS_FIELD
#define RTL_CONTAINS_FIELD(P_, SIZE_, FIELD_) \
  ((ULONG_PTR)(P_) + (ULONG_PTR)(SIZE_) > (ULONG_PTR)&((P_)->FIELD_) + sizeof((P_)->FIELD_))
#endif

static __inline BOOLEAN IsPowerOf2(IN ULONG Number)
{
    if(Number == 0)
		return FALSE;
    return (Number & (Number - 1)) == 0;
}

static __inline ULONG ModPow2(IN ULONG Address, IN ULONG Alignment)
{
    ASSERT(IsPowerOf2(Alignment));
    return Address & (Alignment - 1);
}

static __inline BOOLEAN IsAligned(IN ULONG Address, IN ULONG Alignment)
{
    return ModPow2(Address, Alignment) == 0;
}

static __inline BOOLEAN AlignUp(OUT PULONG AlignedAddress, IN ULONG Address, IN ULONG Alignment)
{
    ULONG nExcess = ModPow2(Address, Alignment);

    if(nExcess == 0)
    {
	*AlignedAddress = Address;
	return nExcess == 0;
    }
    else
	return Intsafe_AddULong32(AlignedAddress, Address, Alignment - nExcess);
}

#define PEFMT_FIELDS_EQUAL(TYPE1_, TYPE2_, FIELD_) \
 ( \
  (FIELD_OFFSET(TYPE1_, FIELD_) == FIELD_OFFSET(TYPE2_, FIELD_)) && \
  (RTL_FIELD_SIZE(TYPE1_, FIELD_) == RTL_FIELD_SIZE(TYPE2_, FIELD_)) \
 )

/*
 References:
  [1] Microsoft Corporation, "Microsoft Portable Executable and Common Object
      File Format Specification", revision 6.0 (February 1999)
*/
NTSTATUS NTAPI PeFmtCreateSection(IN CONST VOID * FileHeader,
				  IN SIZE_T FileHeaderSize,
				  IN PVOID File,
				  OUT PMM_IMAGE_SECTION_OBJECT ImageSectionObject,
				  OUT PULONG Flags,
				  IN PEXEFMT_CB_READ_FILE ReadFileCb,
				  IN PEXEFMT_CB_ALLOCATE_SEGMENTS AllocateSegmentsCb)
{
    NTSTATUS nStatus;
    ULONG cbFileHeaderOffsetSize = 0;
    ULONG cbSectionHeadersOffset = 0;
    ULONG cbSectionHeadersSize;
    ULONG cbSectionHeadersOffsetSize = 0;
    ULONG cbOptHeaderSize;
    ULONG cbHeadersSize = 0;
    ULONG nSectionAlignment;
    ULONG nFileAlignment;
    const IMAGE_DOS_HEADER * pidhDosHeader;
    const IMAGE_NT_HEADERS32 * pinhNtHeader;
    const IMAGE_OPTIONAL_HEADER32 * piohOptHeader;
    const IMAGE_SECTION_HEADER * pishSectionHeaders;
    PMM_SECTION_SEGMENT pssSegments;
    LARGE_INTEGER lnOffset;
    PVOID pBuffer;
    ULONG nPrevVirtualEndOfSegment = 0;
    ULONG nFileSizeOfHeaders = 0;
    ULONG i;

    ASSERT(FileHeader);
    ASSERT(FileHeaderSize > 0);
    ASSERT(File);
    ASSERT(ImageSectionObject);
    ASSERT(ReadFileCb);
    ASSERT(AllocateSegmentsCb);

    ASSERT(Intsafe_CanOffsetPointer(FileHeader, FileHeaderSize));

    C_ASSERT(EXEFMT_LOAD_HEADER_SIZE >= sizeof(IMAGE_DOS_HEADER));
    ASSERT(((UINT_PTR)FileHeader % TYPE_ALIGNMENT(IMAGE_DOS_HEADER)) == 0);

#define DIE(ARGS_) { DPRINT ARGS_; goto l_Return; }

    pBuffer = NULL;
    pidhDosHeader = FileHeader;

    /* DOS HEADER */
    nStatus = STATUS_ROS_EXEFMT_UNKNOWN_FORMAT;

    /* image too small to be an MZ executable */
    if(FileHeaderSize < sizeof(IMAGE_DOS_HEADER))
	DIE(("Too small to be an MZ executable, size is %lu\n", FileHeaderSize));

    /* no MZ signature */
    if(pidhDosHeader->e_magic != IMAGE_DOS_SIGNATURE)
	DIE(("No MZ signature found, e_magic is %hX\n", pidhDosHeader->e_magic));

    /* not a Windows executable */
    if(pidhDosHeader->e_lfanew <= 0)
	DIE(("Not a Windows executable, e_lfanew is %d\n", pidhDosHeader->e_lfanew));

    /* NT HEADER */
    nStatus = STATUS_INVALID_IMAGE_FORMAT;

    if(!Intsafe_AddULong32(&cbFileHeaderOffsetSize, pidhDosHeader->e_lfanew, RTL_SIZEOF_THROUGH_FIELD(IMAGE_NT_HEADERS32, FileHeader)))
	DIE(("The DOS stub is too large, e_lfanew is %X\n", pidhDosHeader->e_lfanew));

    if(FileHeaderSize < cbFileHeaderOffsetSize)
	pinhNtHeader = NULL;
    else
    {
	/*
	 * we already know that Intsafe_CanOffsetPointer(FileHeader, FileHeaderSize),
	 * and FileHeaderSize >= cbFileHeaderOffsetSize, so this holds true too
	 */
	ASSERT(Intsafe_CanOffsetPointer(FileHeader, pidhDosHeader->e_lfanew));
	pinhNtHeader = (PVOID)((UINT_PTR)FileHeader + pidhDosHeader->e_lfanew);
    }

    C_ASSERT(sizeof(IMAGE_NT_HEADERS32) <= sizeof(IMAGE_NT_HEADERS64));
    C_ASSERT(TYPE_ALIGNMENT(IMAGE_NT_HEADERS32) == TYPE_ALIGNMENT(IMAGE_NT_HEADERS64));
    C_ASSERT(RTL_SIZEOF_THROUGH_FIELD(IMAGE_NT_HEADERS32, FileHeader) == RTL_SIZEOF_THROUGH_FIELD(IMAGE_NT_HEADERS64, FileHeader));
    C_ASSERT(FIELD_OFFSET(IMAGE_NT_HEADERS32, OptionalHeader) == FIELD_OFFSET(IMAGE_NT_HEADERS64, OptionalHeader));

    /*
     * the buffer doesn't contain the NT file header, or the alignment is wrong: we
     * need to read the header from the file
     */
    if(FileHeaderSize < cbFileHeaderOffsetSize ||
       (UINT_PTR)pinhNtHeader % TYPE_ALIGNMENT(IMAGE_NT_HEADERS32) != 0)
    {
	ULONG cbNtHeaderSize;
	ULONG cbReadSize;
	PVOID pData;

l_ReadHeaderFromFile:
	cbNtHeaderSize = 0;
	lnOffset.QuadPart = pidhDosHeader->e_lfanew;

	/* read the header from the file */
	nStatus = ReadFileCb(File, &lnOffset, sizeof(IMAGE_NT_HEADERS64), &pData, &pBuffer, &cbReadSize);

	if(!NT_SUCCESS(nStatus))
	    DIE(("ReadFile failed, status %08X\n", nStatus));

	ASSERT(pData);
	ASSERT(pBuffer);
	ASSERT(cbReadSize > 0);

	nStatus = STATUS_INVALID_IMAGE_FORMAT;

	/* the buffer doesn't contain the file header */
	if(cbReadSize < RTL_SIZEOF_THROUGH_FIELD(IMAGE_NT_HEADERS32, FileHeader))
	    DIE(("The file doesn't contain the PE file header\n"));

	pinhNtHeader = pData;

	/* object still not aligned: copy it to the beginning of the buffer */
	if((UINT_PTR)pinhNtHeader % TYPE_ALIGNMENT(IMAGE_NT_HEADERS32) != 0)
	{
	    ASSERT((UINT_PTR)pBuffer % TYPE_ALIGNMENT(IMAGE_NT_HEADERS32) == 0);
	    RtlMoveMemory(pBuffer, pData, cbReadSize);
	    pinhNtHeader = pBuffer;
	}

	/* invalid NT header */
	nStatus = STATUS_INVALID_IMAGE_PROTECT;

	if(pinhNtHeader->Signature != IMAGE_NT_SIGNATURE)
	    DIE(("The file isn't a PE executable, Signature is %X\n", pinhNtHeader->Signature));

	nStatus = STATUS_INVALID_IMAGE_FORMAT;

	if(!Intsafe_AddULong32(&cbNtHeaderSize, pinhNtHeader->FileHeader.SizeOfOptionalHeader, FIELD_OFFSET(IMAGE_NT_HEADERS32, OptionalHeader)))
	    DIE(("The full NT header is too large\n"));

	/* the buffer doesn't contain the whole NT header */
	if(cbReadSize < cbNtHeaderSize)
	    DIE(("The file doesn't contain the full NT header\n"));
    }
    else
    {
	ULONG cbOptHeaderOffsetSize = 0;

	nStatus = STATUS_INVALID_IMAGE_FORMAT;

	/* don't trust an invalid NT header */
	if(pinhNtHeader->Signature != IMAGE_NT_SIGNATURE)
	    DIE(("The file isn't a PE executable, Signature is %X\n", pinhNtHeader->Signature));

	if(!Intsafe_AddULong32(&cbOptHeaderOffsetSize, pidhDosHeader->e_lfanew, FIELD_OFFSET(IMAGE_NT_HEADERS32, OptionalHeader)))
	    DIE(("The DOS stub is too large, e_lfanew is %X\n", pidhDosHeader->e_lfanew));

	if(!Intsafe_AddULong32(&cbOptHeaderOffsetSize, cbOptHeaderOffsetSize, pinhNtHeader->FileHeader.SizeOfOptionalHeader))
	    DIE(("The NT header is too large, SizeOfOptionalHeader is %X\n", pinhNtHeader->FileHeader.SizeOfOptionalHeader));

	/* the buffer doesn't contain the whole NT header: read it from the file */
	if(cbOptHeaderOffsetSize > FileHeaderSize)
	    goto l_ReadHeaderFromFile;
    }

    /* read information from the NT header */
    piohOptHeader = &pinhNtHeader->OptionalHeader;
    cbOptHeaderSize = pinhNtHeader->FileHeader.SizeOfOptionalHeader;

    nStatus = STATUS_INVALID_IMAGE_FORMAT;

    C_ASSERT(PEFMT_FIELDS_EQUAL(IMAGE_OPTIONAL_HEADER32, IMAGE_OPTIONAL_HEADER64, Magic));

    if(!RTL_CONTAINS_FIELD(piohOptHeader, cbOptHeaderSize, Magic))
	DIE(("The optional header doesn't contain the Magic field, SizeOfOptionalHeader is %X\n", cbOptHeaderSize));

    /* ASSUME: RtlZeroMemory(ImageSectionObject, sizeof(*ImageSectionObject)); */

    switch(piohOptHeader->Magic)
    {
	case IMAGE_NT_OPTIONAL_HDR32_MAGIC:
	case IMAGE_NT_OPTIONAL_HDR64_MAGIC:
	    break;

	default:
	    DIE(("Unrecognized optional header, Magic is %X\n", piohOptHeader->Magic));
    }

    C_ASSERT(PEFMT_FIELDS_EQUAL(IMAGE_OPTIONAL_HEADER32, IMAGE_OPTIONAL_HEADER64, SectionAlignment));
    C_ASSERT(PEFMT_FIELDS_EQUAL(IMAGE_OPTIONAL_HEADER32, IMAGE_OPTIONAL_HEADER64, FileAlignment));

    if (RTL_CONTAINS_FIELD(piohOptHeader, cbOptHeaderSize, SectionAlignment) &&
        RTL_CONTAINS_FIELD(piohOptHeader, cbOptHeaderSize, FileAlignment))
    {
	/* See [1], section 3.4.2 */
	if(piohOptHeader->SectionAlignment < PAGE_SIZE)
	{
	    if(piohOptHeader->FileAlignment != piohOptHeader->SectionAlignment)
		DIE(("Sections aren't page-aligned and the file alignment isn't the same\n"));
	}
	else if(piohOptHeader->SectionAlignment < piohOptHeader->FileAlignment)
	    DIE(("The section alignment is smaller than the file alignment\n"));

	nSectionAlignment = piohOptHeader->SectionAlignment;
	nFileAlignment = piohOptHeader->FileAlignment;

	if(!IsPowerOf2(nSectionAlignment) || !IsPowerOf2(nFileAlignment))
	    DIE(("The section alignment (%u) and file alignment (%u) aren't both powers of 2\n", nSectionAlignment, nFileAlignment));
    }
    else
    {
	nSectionAlignment = PAGE_SIZE;
	nFileAlignment = PAGE_SIZE;
    }

    ASSERT(IsPowerOf2(nSectionAlignment));
    ASSERT(IsPowerOf2(nFileAlignment));

    switch(piohOptHeader->Magic)
    {
	/* PE32 */
	case IMAGE_NT_OPTIONAL_HDR32_MAGIC:
	{
	    if(RTL_CONTAINS_FIELD(piohOptHeader, cbOptHeaderSize, ImageBase))
		ImageSectionObject->ImageBase = piohOptHeader->ImageBase;

	    if(RTL_CONTAINS_FIELD(piohOptHeader, cbOptHeaderSize, SizeOfStackReserve))
		ImageSectionObject->StackReserve = piohOptHeader->SizeOfStackReserve;

	    if(RTL_CONTAINS_FIELD(piohOptHeader, cbOptHeaderSize, SizeOfStackCommit))
		ImageSectionObject->StackCommit = piohOptHeader->SizeOfStackCommit;

	    break;
	}

	/* PE32+ */
	case IMAGE_NT_OPTIONAL_HDR64_MAGIC:
	{
	    const IMAGE_OPTIONAL_HEADER64 * pioh64OptHeader;

	    pioh64OptHeader = (const IMAGE_OPTIONAL_HEADER64 *)piohOptHeader;

	    if(RTL_CONTAINS_FIELD(pioh64OptHeader, cbOptHeaderSize, ImageBase))
	    {
		if(pioh64OptHeader->ImageBase > MAXULONG_PTR)
		    DIE(("ImageBase exceeds the address space\n"));

		ImageSectionObject->ImageBase = pioh64OptHeader->ImageBase;
	    }

	    if(RTL_CONTAINS_FIELD(pioh64OptHeader, cbOptHeaderSize, SizeOfStackReserve))
	    {
		if(pioh64OptHeader->SizeOfStackReserve > MAXULONG_PTR)
		    DIE(("SizeOfStackReserve exceeds the address space\n"));

		ImageSectionObject->StackReserve = pioh64OptHeader->SizeOfStackReserve;
	    }

	    if(RTL_CONTAINS_FIELD(pioh64OptHeader, cbOptHeaderSize, SizeOfStackCommit))
	    {
		if(pioh64OptHeader->SizeOfStackCommit > MAXULONG_PTR)
		    DIE(("SizeOfStackCommit exceeds the address space\n"));

		ImageSectionObject->StackCommit = pioh64OptHeader->SizeOfStackCommit;
	    }

	    break;
	}
    }

    /* [1], section 3.4.2 */
    if((ULONG_PTR)ImageSectionObject->ImageBase % 0x10000)
	DIE(("ImageBase is not aligned on a 64KB boundary"));

    C_ASSERT(PEFMT_FIELDS_EQUAL(IMAGE_OPTIONAL_HEADER32, IMAGE_OPTIONAL_HEADER64, Subsystem));
    C_ASSERT(PEFMT_FIELDS_EQUAL(IMAGE_OPTIONAL_HEADER32, IMAGE_OPTIONAL_HEADER64, MinorSubsystemVersion));
    C_ASSERT(PEFMT_FIELDS_EQUAL(IMAGE_OPTIONAL_HEADER32, IMAGE_OPTIONAL_HEADER64, MajorSubsystemVersion));

    if(RTL_CONTAINS_FIELD(piohOptHeader, cbOptHeaderSize, Subsystem))
    {
	ImageSectionObject->Subsystem = piohOptHeader->Subsystem;

	if(RTL_CONTAINS_FIELD(piohOptHeader, cbOptHeaderSize, MinorSubsystemVersion) &&
	   RTL_CONTAINS_FIELD(piohOptHeader, cbOptHeaderSize, MajorSubsystemVersion))
	{
	    ImageSectionObject->MinorSubsystemVersion = piohOptHeader->MinorSubsystemVersion;
	    ImageSectionObject->MajorSubsystemVersion = piohOptHeader->MajorSubsystemVersion;
	}
    }

    C_ASSERT(PEFMT_FIELDS_EQUAL(IMAGE_OPTIONAL_HEADER32, IMAGE_OPTIONAL_HEADER64, AddressOfEntryPoint));

    if(RTL_CONTAINS_FIELD(piohOptHeader, cbOptHeaderSize, AddressOfEntryPoint))
    {
	ImageSectionObject->EntryPoint = piohOptHeader->ImageBase +
                                         piohOptHeader->AddressOfEntryPoint;
    }

    C_ASSERT(PEFMT_FIELDS_EQUAL(IMAGE_OPTIONAL_HEADER32, IMAGE_OPTIONAL_HEADER64, SizeOfCode));

    if(RTL_CONTAINS_FIELD(piohOptHeader, cbOptHeaderSize, SizeOfCode))
	ImageSectionObject->Executable = piohOptHeader->SizeOfCode != 0;
    else
	ImageSectionObject->Executable = TRUE;

    ImageSectionObject->ImageCharacteristics = pinhNtHeader->FileHeader.Characteristics;
    ImageSectionObject->Machine = pinhNtHeader->FileHeader.Machine;

    /* SECTION HEADERS */
    nStatus = STATUS_INVALID_IMAGE_FORMAT;

    /* see [1], section 3.3 */
    if(pinhNtHeader->FileHeader.NumberOfSections > 96)
	DIE(("Too many sections, NumberOfSections is %u\n", pinhNtHeader->FileHeader.NumberOfSections));

    /*
     * the additional segment is for the file's headers. They need to be present for
     * the benefit of the dynamic loader (to locate exports, defaults for thread
     * parameters, resources, etc.)
     */
    ImageSectionObject->NrSegments = pinhNtHeader->FileHeader.NumberOfSections + 1;

    /* file offset for the section headers */
    if(!Intsafe_AddULong32(&cbSectionHeadersOffset, pidhDosHeader->e_lfanew, FIELD_OFFSET(IMAGE_NT_HEADERS32, OptionalHeader)))
	DIE(("Offset overflow\n"));

    if(!Intsafe_AddULong32(&cbSectionHeadersOffset, cbSectionHeadersOffset, pinhNtHeader->FileHeader.SizeOfOptionalHeader))
	DIE(("Offset overflow\n"));

    /* size of the section headers */
    ASSERT(Intsafe_CanMulULong32(pinhNtHeader->FileHeader.NumberOfSections, sizeof(IMAGE_SECTION_HEADER)));
    cbSectionHeadersSize = pinhNtHeader->FileHeader.NumberOfSections * sizeof(IMAGE_SECTION_HEADER);

    if(!Intsafe_AddULong32(&cbSectionHeadersOffsetSize, cbSectionHeadersOffset, cbSectionHeadersSize))
	DIE(("Section headers too large\n"));

    C_ASSERT(PEFMT_FIELDS_EQUAL(IMAGE_OPTIONAL_HEADER32, IMAGE_OPTIONAL_HEADER64, SizeOfHeaders));

    /* size of the executable's headers */
    if(RTL_CONTAINS_FIELD(piohOptHeader, cbOptHeaderSize, SizeOfHeaders))
    {
//	if(!IsAligned(piohOptHeader->SizeOfHeaders, nFileAlignment))
//	    DIE(("SizeOfHeaders is not aligned\n"));

	if(cbSectionHeadersSize > piohOptHeader->SizeOfHeaders)
	    DIE(("The section headers overflow SizeOfHeaders\n"));

	cbHeadersSize = piohOptHeader->SizeOfHeaders;
    }
    else if(!AlignUp(&cbHeadersSize, cbSectionHeadersOffsetSize, nFileAlignment))
	DIE(("Overflow aligning the size of headers\n"));

    if(pBuffer)
    {
	ExFreePool(pBuffer);
	pBuffer = NULL;
    }
    /* WARNING: pinhNtHeader IS NO LONGER USABLE */
    /* WARNING: piohOptHeader IS NO LONGER USABLE */
    /* WARNING: pioh64OptHeader IS NO LONGER USABLE */

    if(FileHeaderSize < cbSectionHeadersOffsetSize)
	pishSectionHeaders = NULL;
    else
    {
	/*
	 * we already know that Intsafe_CanOffsetPointer(FileHeader, FileHeaderSize),
	 * and FileHeaderSize >= cbSectionHeadersOffsetSize, so this holds true too
	 */
	ASSERT(Intsafe_CanOffsetPointer(FileHeader, cbSectionHeadersOffset));
	pishSectionHeaders = (PVOID)((UINT_PTR)FileHeader + cbSectionHeadersOffset);
    }

    /*
     * the buffer doesn't contain the section headers, or the alignment is wrong:
     * read the headers from the file
     */
    if(FileHeaderSize < cbSectionHeadersOffsetSize ||
       (UINT_PTR)pishSectionHeaders % TYPE_ALIGNMENT(IMAGE_SECTION_HEADER) != 0)
    {
	PVOID pData;
	ULONG cbReadSize;

	lnOffset.QuadPart = cbSectionHeadersOffset;

	/* read the header from the file */
	nStatus = ReadFileCb(File, &lnOffset, cbSectionHeadersSize, &pData, &pBuffer, &cbReadSize);

	if(!NT_SUCCESS(nStatus))
	    DIE(("ReadFile failed with status %08X\n", nStatus));

	ASSERT(pData);
	ASSERT(pBuffer);
	ASSERT(cbReadSize > 0);

	nStatus = STATUS_INVALID_IMAGE_FORMAT;

	/* the buffer doesn't contain all the section headers */
	if(cbReadSize < cbSectionHeadersSize)
	    DIE(("The file doesn't contain all of the section headers\n"));

	pishSectionHeaders = pData;

	/* object still not aligned: copy it to the beginning of the buffer */
	if((UINT_PTR)pishSectionHeaders % TYPE_ALIGNMENT(IMAGE_SECTION_HEADER) != 0)
	{
	    ASSERT((UINT_PTR)pBuffer % TYPE_ALIGNMENT(IMAGE_SECTION_HEADER) == 0);
	    RtlMoveMemory(pBuffer, pData, cbReadSize);
	    pishSectionHeaders = pBuffer;
	}
    }

    /* SEGMENTS */
    /* allocate the segments */
    nStatus = STATUS_INSUFFICIENT_RESOURCES;
    ImageSectionObject->Segments = AllocateSegmentsCb(ImageSectionObject->NrSegments);

    if(ImageSectionObject->Segments == NULL)
	DIE(("AllocateSegments failed\n"));

    /* initialize the headers segment */
	pssSegments = ImageSectionObject->Segments;

//  ASSERT(IsAligned(cbHeadersSize, nFileAlignment));

    if(!AlignUp(&nFileSizeOfHeaders, cbHeadersSize, nFileAlignment))
	DIE(("Cannot align the size of the section headers\n"));

    if(!AlignUp(&nPrevVirtualEndOfSegment, cbHeadersSize, nSectionAlignment))
	DIE(("Cannot align the size of the section headers\n"));

    pssSegments[0].FileOffset = 0;
    pssSegments[0].Protection = PAGE_READONLY;
    pssSegments[0].Length = nPrevVirtualEndOfSegment;
    pssSegments[0].RawLength = nFileSizeOfHeaders;
    pssSegments[0].VirtualAddress = 0;
    pssSegments[0].Characteristics = IMAGE_SCN_CNT_INITIALIZED_DATA;
    pssSegments[0].WriteCopy = TRUE;

    /* skip the headers segment */
    ++ pssSegments;

    nStatus = STATUS_INVALID_IMAGE_FORMAT;

    /* convert the executable sections into segments. See also [1], section 4 */
    for(i = 0; i < ImageSectionObject->NrSegments - 1; ++ i)
    {
	ULONG nCharacteristics;

	/* validate the alignment */
	if(!IsAligned(pishSectionHeaders[i].VirtualAddress, nSectionAlignment))
	    DIE(("VirtualAddress[%u] is not aligned\n", i));

	/* sections must be contiguous, ordered by base address and non-overlapping */
	if(pishSectionHeaders[i].VirtualAddress != nPrevVirtualEndOfSegment)
	    DIE(("Memory gap between section %u and the previous\n", i));

	/* ignore explicit BSS sections */
	if(pishSectionHeaders[i].SizeOfRawData != 0)
	{
	    /* validate the alignment */
#if 0
	    /* Yes, this should be a multiple of FileAlignment, but there's
	     * stuff out there that isn't. We can cope with that
	     */
	    if(!IsAligned(pishSectionHeaders[i].SizeOfRawData, nFileAlignment))
		DIE(("SizeOfRawData[%u] is not aligned\n", i));
#endif

//	    if(!IsAligned(pishSectionHeaders[i].PointerToRawData, nFileAlignment))
//		DIE(("PointerToRawData[%u] is not aligned\n", i));

	    /* conversion */
	    pssSegments[i].FileOffset = pishSectionHeaders[i].PointerToRawData;
	    pssSegments[i].RawLength = pishSectionHeaders[i].SizeOfRawData;
	}
	else
	{
	    ASSERT(pssSegments[i].FileOffset == 0);
	    ASSERT(pssSegments[i].RawLength == 0);
	}

	ASSERT(Intsafe_CanAddLong64(pssSegments[i].FileOffset, pssSegments[i].RawLength));

	nCharacteristics = pishSectionHeaders[i].Characteristics;

	/* no explicit protection */
	if((nCharacteristics & (IMAGE_SCN_MEM_EXECUTE | IMAGE_SCN_MEM_READ | IMAGE_SCN_MEM_WRITE)) == 0)
	{
	    if(nCharacteristics & IMAGE_SCN_CNT_CODE)
		nCharacteristics |= IMAGE_SCN_MEM_EXECUTE | IMAGE_SCN_MEM_READ;

	    if(nCharacteristics & IMAGE_SCN_CNT_INITIALIZED_DATA)
		nCharacteristics |= IMAGE_SCN_MEM_READ | IMAGE_SCN_MEM_WRITE;

	    if(nCharacteristics & IMAGE_SCN_CNT_UNINITIALIZED_DATA)
		nCharacteristics |= IMAGE_SCN_MEM_READ | IMAGE_SCN_MEM_WRITE;
	}

	/* see table above */
	pssSegments[i].Protection = SectionCharacteristicsToProtect[nCharacteristics >> 28];
	pssSegments[i].WriteCopy = !(nCharacteristics & IMAGE_SCN_MEM_SHARED);

	if(pishSectionHeaders[i].Misc.VirtualSize == 0 || pishSectionHeaders[i].Misc.VirtualSize < pishSectionHeaders[i].SizeOfRawData)
	    pssSegments[i].Length = pishSectionHeaders[i].SizeOfRawData;
	else
	    pssSegments[i].Length = pishSectionHeaders[i].Misc.VirtualSize;

	if(!AlignUp(&pssSegments[i].Length, pssSegments[i].Length, nSectionAlignment))
	    DIE(("Cannot align the virtual size of section %u\n", i));

	ASSERT(IsAligned(pssSegments[i].Length, nSectionAlignment));

	if(pssSegments[i].Length == 0)
	    DIE(("Virtual size of section %u is null\n", i));

	pssSegments[i].VirtualAddress = pishSectionHeaders[i].VirtualAddress;
	pssSegments[i].Characteristics = pishSectionHeaders[i].Characteristics;

	/* ensure the memory image is no larger than 4GB */
	if(!Intsafe_AddULong32(&nPrevVirtualEndOfSegment, pssSegments[i].VirtualAddress, pssSegments[i].Length))
	    DIE(("The image is larger than 4GB\n"));
    }

    /* spare our caller some work in validating the segments */
    *Flags = EXEFMT_LOAD_ASSUME_SEGMENTS_SORTED | EXEFMT_LOAD_ASSUME_SEGMENTS_NO_OVERLAP;

    if(nSectionAlignment >= PAGE_SIZE)
	*Flags |= EXEFMT_LOAD_ASSUME_SEGMENTS_PAGE_ALIGNED;

    /* Success */
    nStatus = STATUS_ROS_EXEFMT_LOADED_FORMAT | EXEFMT_LOADED_PE32;

l_Return:
    if(pBuffer)
	ExFreePool(pBuffer);

    return nStatus;
}

/* EOF */