{
function xLoadLibrary(Src: Pointer; Imports: array of TImportItem): TLibInfo;
procedure xFreeLibrary(hModule: TLibInfo);
}
unit DLLUnit;
interface
uses
Windows;
type
TImportItem = record
Name: string;
PProcVar: ^Pointer;
end;
TwordArr = array [0..0] of word;
PwordArr = ^TwordArr;
TdwordArr = array [0..0] of dword;
PdwordArr = ^TdwordArr;
PImageImportDescriptor = ^TImageImportDescriptor;
TImageImportDescriptor = packed record
OriginalFirstThunk: dword;
TimeDateStamp: dword;
ForwarderChain: dword;
Name: dword;
FirstThunk: dword;
end;
PImageBaseRelocation= ^TImageBaseRelocation;
TImageBaseRelocation = packed record
VirtualAddress: cardinal;
SizeOfBlock: cardinal;
end;
TDllEntryProc = function(hinstDLL: HMODULE; dwReason: dword; lpvReserved: Pointer): Boolean; stdcall;
TStringArray = array of string;
TLibInfo = record
ImageBase: Pointer;
DllProc: TDllEntryProc;
LibsUsed: TStringArray;
end;
PLibInfo = ^TLibInfo;
PPointer = ^Pointer;
TSections = array [0..100000] of TImageSectionHeader;
const
IMPORTED_NAME_OFFSET = $00000002;
IMAGE_ORDINAL_FLAG32 = $80000000;
IMAGE_ORDINAL_MASK32 = $0000FFFF;
function xLoadLibrary(Src: Pointer; Imports: array of TImportItem): TLibInfo;
function xFreeLibrary(LoadedLib: TLibInfo): boolean;
implementation
function xFreeLibrary(LoadedLib: TLibInfo): boolean;
var
ObjectLoop: integer;
begin
Result := False;
with LoadedLib do
begin
if @DllProc <> nil then
begin
DllProc(HModule(LoadedLib.ImageBase), DLL_PROCESS_DETACH, nil);
end;
for ObjectLoop := 0 to Length(LibsUsed) - 1 do
begin
if ObjectLoop >= Length(LibsUsed) then Exit;
FreeLibrary(GetModuleHandle(pchar(LibsUsed[ObjectLoop])));
end;
SetLength(LibsUsed, 0);
end;
VirtualFree(LoadedLib.ImageBase, 0, MEM_RELEASE);
Result := True;
end;
function xLoadLibrary(Src: Pointer; Imports: array of TImportItem): TLibInfo;
var
ImageBase: pointer;
ImageBaseDelta: integer;
ImageNtHeaders: PImageNtHeaders;
PSections: ^TSections;
SectionLoop: integer;
SectionBase: pointer;
VirtualSectionSize, RawSectionSize: cardinal;
OldProtect: cardinal;
NewLibInfo: TLibInfo;
function StrToInt(S: string): integer;
begin
Val(S, Result, Result);
end;
procedure Add(Strings: TStringArray; Text: string);
begin
SetLength(Strings, Length(Strings) + 1);
Strings[Length(Strings)-1] := Text;
end;
function Find(Strings: array of string; Text: string; var Index: integer): boolean;
var
StringLoop: integer;
begin
Result := False;
for StringLoop := 0 to Length(Strings) - 1 do
begin
if lstrcmpi(pchar(Strings[StringLoop]), pchar(Text)) = 0 then
begin
Index := StringLoop;
Result := True;
end;
end;
end;
function GetSectionProtection(ImageScn: cardinal): cardinal;
begin
Result := 0;
if (ImageScn and IMAGE_SCN_MEM_NOT_CACHED) <> 0 then
begin
Result := Result or PAGE_NOCACHE;
end;
if (ImageScn and IMAGE_SCN_MEM_EXECUTE) <> 0 then
begin
if (ImageScn and IMAGE_SCN_MEM_READ)<> 0 then
begin
if (ImageScn and IMAGE_SCN_MEM_WRITE)<> 0 then
begin
Result := Result or PAGE_EXECUTE_READWRITE
end
else
begin
Result := Result or PAGE_EXECUTE_READ
end;
end
else if (ImageScn and IMAGE_SCN_MEM_WRITE) <> 0 then
begin
Result := Result or PAGE_EXECUTE_WRITECOPY
end
else
begin
Result := Result or PAGE_EXECUTE
end;
end
else if (ImageScn and IMAGE_SCN_MEM_READ)<> 0 then
begin
if (ImageScn and IMAGE_SCN_MEM_WRITE) <> 0 then
begin
Result := Result or PAGE_READWRITE
end
else
begin
Result := Result or PAGE_READONLY
end
end
else if (ImageScn and IMAGE_SCN_MEM_WRITE) <> 0 then
begin
Result := Result or PAGE_WRITECOPY
end
else
begin
Result := Result or PAGE_NOACCESS;
end;
end;
procedure ProcessExports(PExports: PImageExportDirectory; BlockSize: cardinal);
var
ExportLoop: byte;
ImportedFn: cardinal;
PFnName: pchar;
FnIndex: dword;
function IsForwarderString(Data: pchar): boolean;
begin
Result := Data > PExports;
if Result then Result := cardinal(Data - PExports) < BlockSize;
end;
function GetForwardedSymbol(ForwarderString: pchar):pointer;
var
sForwarderString, DllName: string;
ForwarderLoop: integer;
LibHandle: HModule;
begin
sForwarderString := ForwarderString;
while ForwarderString^ <> '.' do
begin
Inc(ForwarderString);
end;
DllName := Copy(sForwarderString, 1, pos('.', sForwarderString) - 1);
if not Find(NewLibInfo.LibsUsed, DllName, ForwarderLoop) then
begin
LibHandle := LoadLibrary(pchar(DllName));
Add(NewLibInfo.LibsUsed, DllName);
end
else
begin
LibHandle := cardinal(NewLibInfo.LibsUsed[ForwarderLoop]);
end;
if ForwarderString^ = '#' then ForwarderString := pointer(StrToInt((ForwarderString + 1)));
Result := GetProcAddress(LibHandle, ForwarderString);
end;
begin
for ExportLoop := 0 to PExports.NumberOfNames - 1 do
begin
PFnName := pchar(PdwordArr(cardinal(PExports.AddressOfNames) + cardinal(ImageBase))^[ExportLoop] + cardinal(ImageBase));
for ImportedFn := low(Imports) to high(Imports) do
begin
if Imports[ImportedFn].Name = PFnName then
begin
FnIndex := PwordArr(cardinal(PExports.AddressOfNameOrdinals) + cardinal(ImageBase))^[ExportLoop];
Imports[ImportedFn].PProcVar^ := pointer(PdwordArr(cardinal(PExports.AddressOfFunctions) + cardinal(ImageBase))^[FnIndex] + cardinal(ImageBase));
if IsForwarderString(Imports[ImportedFn].PProcVar^)then
begin
Imports[ImportedFn].PProcVar^ := GetForwardedSymbol(Imports[ImportedFn].PProcVar^);
end;
end;
end;
end;
end;
procedure ProcessRelocs(PRelocs:PImageBaseRelocation);
var
PReloc: PImageBaseRelocation;
RelocsSize: cardinal;
Reloc: PWord;
ModCount: cardinal;
RelocLoop: cardinal;
begin
PReloc := PRelocs;
RelocsSize := ImageNtHeaders.OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_BASERELOC].Size;
while cardinal(PReloc) - cardinal(PRelocs) < RelocsSize do
begin
ModCount := (PReloc.SizeOfBlock-Sizeof(PReloc^)) div 2;
Reloc := pointer(cardinal(PReloc)+sizeof(PReloc^));
for RelocLoop := 0 to ModCount - 1 do
begin
if Reloc^ and $f000 <> 0 then Inc(pdword(cardinal(ImageBase) + PReloc.VirtualAddress + (Reloc^ and $0fff))^, ImageBaseDelta);
Inc(Reloc);
end;
PReloc := pointer(Reloc);
end;
end;
procedure ProcessImports(PImports: PImageImportDescriptor);
var
PImport: PImageImportDescriptor;
Import: LPDword;
PImportedName: pchar;
LibHandle: HModule;
ProcAddress: pointer;
PLibName: pchar;
ImportLoop: integer;
function IsImportByOrdinal(ImportDescriptor: dword; HLib: THandle): boolean;
begin
Result := (ImportDescriptor and IMAGE_ORDINAL_FLAG32) <> 0;
end;
begin
PImport := PImports;
while PImport.Name<>0 do
begin
PLibName := pchar(cardinal(PImport.Name) + cardinal(ImageBase));
if not Find(NewLibInfo.LibsUsed, PLibName, ImportLoop) then
begin
LibHandle := LoadLibrary(PLibName);
Add(NewLibInfo.LibsUsed, PLibName);
end
else
begin
LibHandle := cardinal(NewLibInfo.LibsUsed[ImportLoop]);
end;
if PImport.TimeDateStamp = 0 then
begin
Import := LPDword(pImport.FirstThunk+cardinal(ImageBase))
end
else
begin
Import := LPDword(pImport.OriginalFirstThunk + cardinal(ImageBase));
end;
while Import^ <> 0 do
begin
if IsImportByOrdinal(Import^, LibHandle) then
begin
ProcAddress := GetProcAddress(LibHandle, pchar(Import^ and $ffff))
end
else
begin
PImportedName := pchar(Import^ + cardinal(ImageBase) + IMPORTED_NAME_OFFSET);
ProcAddress := GetProcAddress(LibHandle, PImportedName);
end;
PPointer(Import)^ := ProcAddress;
Inc(Import);
end;
Inc(PImport);
end;
end;
begin
ImageNtHeaders := pointer(int64(cardinal(Src)) + PImageDosHeader(Src)._lfanew);
ImageBase := VirtualAlloc(nil, ImageNtHeaders.OptionalHeader.SizeOfImage, MEM_RESERVE, PAGE_NOACCESS);
ImageBaseDelta := cardinal(ImageBase) - ImageNtHeaders.OptionalHeader.ImageBase;
SectionBase := VirtualAlloc(ImageBase, ImageNtHeaders.OptionalHeader.SizeOfHeaders, MEM_COMMIT, PAGE_READWRITE);
Move(Src^, SectionBase^, ImageNtHeaders.OptionalHeader.SizeOfHeaders);
VirtualProtect(SectionBase, ImageNtHeaders.OptionalHeader.SizeOfHeaders, PAGE_READONLY, OldProtect);
PSections := pointer(pchar(@(ImageNtHeaders.OptionalHeader)) + ImageNtHeaders.FileHeader.SizeOfOptionalHeader);
for SectionLoop := 0 to ImageNtHeaders.FileHeader.NumberOfSections - 1 do
begin
VirtualSectionSize := PSections[SectionLoop].Misc.VirtualSize;
RawSectionSize := PSections[SectionLoop].SizeOfRawData;
if VirtualSectionSize < RawSectionSize then
begin
VirtualSectionSize := VirtualSectionSize xor RawSectionSize;
RawSectionSize := VirtualSectionSize xor RawSectionSize;
VirtualSectionSize := VirtualSectionSize xor RawSectionSize;
end;
SectionBase := VirtualAlloc(PSections[SectionLoop].VirtualAddress + pchar(ImageBase), VirtualSectionSize, MEM_COMMIT, PAGE_READWRITE);
FillChar(SectionBase^, VirtualSectionSize, 0);
Move((pchar(src) + PSections[SectionLoop].PointerToRawData)^, SectionBase^, RawSectionSize);
end;
NewLibInfo.DllProc := TDllEntryProc(ImageNtHeaders.OptionalHeader.AddressOfEntryPoint + cardinal(ImageBase));
NewLibInfo.ImageBase := ImageBase;
SetLength(NewLibInfo.LibsUsed, 0);
if ImageNtHeaders.OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_BASERELOC].VirtualAddress <> 0 then ProcessRelocs(pointer(ImageNtHeaders.OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_BASERELOC].VirtualAddress + cardinal(ImageBase)));
if ImageNtHeaders.OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_IMPORT].VirtualAddress <> 0 then ProcessImports(pointer(ImageNtHeaders.OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_IMPORT].VirtualAddress + cardinal(ImageBase)));
for SectionLoop := 0 to ImageNtHeaders.FileHeader.NumberOfSections - 1 do
begin
VirtualProtect(PSections[SectionLoop].VirtualAddress + pchar(ImageBase), PSections[SectionLoop].Misc.VirtualSize, GetSectionProtection(PSections[SectionLoop].Characteristics), OldProtect);
end;
if @NewLibInfo.DllProc <> nil then
begin
if not NewLibInfo.DllProc(cardinal(ImageBase), DLL_PROCESS_ATTACH, nil) then
begin
NewLibInfo.DllProc := nil;
xFreeLibrary(Result);
end;
end;
if ImageNtHeaders.OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT].VirtualAddress <> 0 then ProcessExports(pointer(ImageNtHeaders.OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT].VirtualAddress + cardinal(ImageBase)), ImageNtHeaders.OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT].Size);
Result := NewLibInfo;
end;
end.