内存动态搜索API：LoadLibraryA

内存动态搜索API：LoadLibraryA
(利用用PEB获取地址kernel32.dll基址然后再用GetProcAddress搜出函数指针)
GetProcAddress
(
这个是人工构件的,原理利用函数名称的Crc32数值然后依次比较
导入表中函数的地址，。。。。。。
)
然后再开始调用...........
实例代码:
PROGRAM Project;
USES
  APISearchEngine;
CONST
  MessageBoxA = $572D5D8E; //的Crc32数值
VAR
  MessageBox : FUNCTION(hWnd:DWORD;lpText,lpCaption:PChar;uType:DWORD) : Integer; STDCALL;
  LoadLibrary:function(lpLibFileName: PChar): HMODULE; stdcall;
function IntToStr(Value: Integer): String;
begin
  Str(Value, Result);
end;
BEGIN
  BuildCRC32Table;
  @LoadLibrary:=MyLoadLibraryA;
  MessageBox:=GetProcAddress(LoadLibrary('user32.dll'),MessageBoxA);
  Messagebox(0,Pchar('LoadLibraryA函数地址为:'+IntToStr(integer(MyLoadLibraryA))),'Message',0);
END.
}
UNIT APISearchEngine;
{$WARNINGS OFF}
INTERFACE
type
DWORD=LongWord;
  
PROCEDURE BuildCRC32Table;
FUNCTION  CalculateCRC32(VAR Buffer;CONST Size:DWORD) : DWORD;
FUNCTION GetProcAddress(Module:Cardinal;ProcessCRC:DWORD) : Pointer;
FUNCTION MyLoadLibraryA:Pointer;
IMPLEMENTATION
CONST
  IMAGE_DIRECTORY_ENTRY_EXPORT     = 0;
  SIZE_OF_80387_REGISTERS          = 80;
  IMAGE_NUMBEROF_DIRECTORY_ENTRIES = 16;
  MAX_API_STRING_LENGTH            = 150;
  IMAGE_DOS_SIGNATURE              = $5A4D;
  IMAGE_NT_SIGNATURE               = $00004550;
  MIN_KERNEL_SEARCH_BASE           = $70000000;
TYPE
  PImageDosHeader               =^TImageDosHeader;
  TImageDosHeader               = PACKED RECORD
    e_magic                     : WORD;
    e_cblp                      : WORD;
    e_cp                        : WORD;
    e_crlc                      : WORD;
    e_cparhdr                   : WORD;
    e_minalloc                  : WORD;
    e_maxalloc                  : WORD;
    e_ss                        : WORD;
    e_sp                        : WORD;
    e_csum                      : WORD;
    e_ip                        : WORD;
    e_cs                        : WORD;
    e_lfarlc                    : WORD;
    e_ovno                      : WORD;
    e_res                       : ARRAY [0..3] OF WORD;
    e_oemid                     : WORD;
    e_oeminfo                   : WORD;
    e_res2                      : ARRAY [0..9] OF WORD;
    _lfanew                     : LongInt;
  END;
  PImageFileHeader              =^TImageFileHeader;
  TImageFileHeader              = PACKED RECORD
    Machine                     : WORD;
    NumberOfSections            : WORD;
    TimeDateStamp               : LongWord;
    PointerToSymbolTable        : LongWord;
    NumberOfSymbols             : LongWord;
    SizeOfOptionalHeader        : WORD;
    Characteristics             : WORD;
  END;
  PImageDataDirectory           =^TImageDataDirectory;
  TImageDataDirectory           = RECORD
    VirtualAddress              : LongWord;
    Size                        : LongWord;
  END;
  PImageOptionalHeader          =^TImageOptionalHeader;
  TImageOptionalHeader          = PACKED RECORD
    Magic                       : WORD;
    MajorLinkerVersion          : Byte;
    MinorLinkerVersion          : Byte;
    SizeOfCode                  : LongWord;
    SizeOfInitializedData       : LongWord;
    SizeOfUninitializedData     : LongWord;
    AddressOfEntryPoint         : LongWord;
    BaseOfCode                  : LongWord;
    BaseOfData                  : LongWord;
    ImageBase                   : LongWord;
    SectionAlignment            : LongWord;
    FileAlignment               : LongWord;
    MajorOperatingSystemVersion : WORD;
    MinorOperatingSystemVersion : WORD;
    MajorImageVersion           : WORD;
    MinorImageVersion           : WORD;
    MajorSubsystemVersion       : WORD;
    MinorSubsystemVersion       : WORD;
    Win32VersionValue           : LongWord;
    SizeOfImage                 : LongWord;
    SizeOfHeaders               : LongWord;
    CheckSum                    : LongWord;
    Subsystem                   : WORD;
    DllCharacteristics          : WORD;
    SizeOfStackReserve          : LongWord;
    SizeOfStackCommit           : LongWord;
    SizeOfHeapReserve           : LongWord;
    SizeOfHeapCommit            : LongWord;
    LoaderFlags                 : LongWord;
    NumberOfRvaAndSizes         : LongWord;
    DataDirectory               : PACKED ARRAY[0..IMAGE_NUMBEROF_DIRECTORY_ENTRIES-1] OF TImageDataDirectory;
  END;
  PImageNtHeaders               =^TImageNtHeaders;
  TImageNtHeaders               = PACKED RECORD
    Signature                   : LongWord;
    FileHeader                  : TImageFileHeader;
    OptionalHeader              : TImageOptionalHeader;
  END;
  PImageExportDirectory         =^TImageExportDirectory;
  TImageExportDirectory         = PACKED RECORD
    Characteristics             : LongWord;
    TimeDateStamp               : LongWord;
    MajorVersion                : WORD;
    MinorVersion                : WORD;
    Name                        : LongWord;
    Base                        : LongWord;
    NumberOfFunctions           : LongWord;
    NumberOfNames               : LongWord;
    AddressOfFunctions          :^PLongWord;
    AddressOfNames              :^PLongWord;
    AddressOfNameOrdinals       :^PWord;
  END;
VAR
  CRC32TAB : ARRAY[0..255] OF DWORD;
PROCEDURE BuildCRC32Table; ASSEMBLER;
ASM
    mov ebx, 0EDB88320h
    lea edi, crc32tab
    xor ecx, ecx
  @loc1:
    mov eax, ecx
    mov edx, 8
  @loc2:
    test eax, 1
    jz  @loc3
    shr eax, 1
    xor eax, ebx
    jmp @loc4
  @loc3:
    shr eax, 1
  @loc4:
    dec edx
    jnz @loc2
    stosd
    inc ecx
    cmp ecx, 256
    jb  @loc1
END;
FUNCTION CalculateCRC32(VAR Buffer;CONST Size:DWORD) : DWORD; ASSEMBLER;
ASM
    push esi
    push edi
    push ebx
    mov edi,edx
    mov esi,eax
    xor ebx,ebx
    mov eax,$ffffffff
    mov ecx,edi
    shr ecx,2
    jecxz @Rest
  @Loop:
    mov edx,[esi]
    mov bl,al
    xor bl,dl
    shr eax,8
    xor eax,dword ptr [CRC32tab+ebx*4]
    mov bl,al
    xor bl,dh
    shr eax,8
    xor eax,dword ptr [CRC32tab+ebx*4]
    shr edx,16
    mov bl,al
    xor bl,dl
    shr eax,8
    xor eax,dword ptr [CRC32tab+ebx*4]
    mov bl,al
    xor bl,dh
    shr eax,8
    xor eax,dword ptr [CRC32tab+ebx*4]
    add esi,4
    loop @Loop
  @Rest:
    mov ecx,edi
    and ecx,3
    jecxz @End
  @Loop_Rest:
    mov bl,al
    xor bl,[esi]
    shr eax,8
    inc esi
    xor eax,dword ptr [CRC32tab+ebx*4]
    loop @Loop_Rest
@End:
    xor eax,$ffffffff
    pop ebx
    pop edi
    pop esi
END;
//------------------------------------------------------------------------------
FUNCTION GetProcAddress(Module:Cardinal;ProcessCRC:DWORD) : Pointer;
VAR
  ExportName           : pChar;
  Address              : Cardinal;
  J                    : Cardinal;
  ImageDosHeader       : PImageDosHeader;
  ImageNTHeaders       : PImageNTHeaders;
  ImageExportDirectory : PImageExportDirectory;
BEGIN
  ImageDosHeader:=Pointer(Module);
  ImageNTHeaders:=Pointer(Module+ImageDosHeader._lfanew);
  ImageExportDirectory:=Pointer(ImageNtHeaders.OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT].VirtualAddress+Module);
  J:=0;
  Address:=0;
  REPEAT
    ExportName:=Pointer(Cardinal(Pointer(Cardinal(ImageExportDirectory.AddressOfNames)+Module+J*4)^)+Module);
    IF CalculateCRC32(ExportName^,Length(ExportName))=ProcessCRC THEN
      Address:=Cardinal(Pointer(Word(Pointer(J SHL 1+Cardinal(
               ImageExportDirectory.AddressOfNameOrdinals)+Module)^) AND
               $0000FFFF SHL 2+Cardinal(ImageExportDirectory.AddressOfFunctions)
               +Module)^)+Module;
    Inc(J);
  UNTIL (Address<>0)OR(J=ImageExportDirectory.NumberOfNames);
  Result:=Pointer(Address);
END;
FUNCTION MyLoadLibraryA:Pointer;
const
  MyLoadLibraryA=$3FC1BD8D;//LoadLibraryA的Crc32数值
asm
  mov eax,fs:$30
mov eax,[eax + $0c]
mov esi,[eax + $1c]
lodsd
mov eax,[eax+$08]
  mov edx,MyLoadLibraryA
  call GetProcAddress
end;
END.