从内存中加载并运行exe (c)

原理很简单：就是“借尸还魂”，启动一个僵尸进程（NT下可以是自身程序启动的另一个进程），然后在它运行前将其整个替换成内存中的exe内容，待正式运行后执行的就是你的目标代码了。

不过代码中还有一些不尽人意的地方，比如在98下运行会留一个僵尸程序的壳在硬盘上（其实那个僵尸程序本身就是一个完整的可执行程序，直接运行的话只显示一条错误信息然后就退出了）。另外由于客观条件限制，代码没有经过充分测试，只在XP下进行了一些初步测试：普通exe都能正常运行，upx压缩过的exe绝大多数情况下都能运行，只有在不能卸载僵尸外壳时才有问题（upx压缩过的exe没有重定向表，无法加载到其它地址运行）。

如果有bug望告之，如果有更好的方法特别是能解决98下的遗留尾巴的话希望不吝赐教。
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小弟没有翻译Win98下处理的方法，请大家参考原文：）

// MemPE.cpp : Defines the entry point for the DLL application.
//

#include "stdafx.h"

typedef IMAGE_SECTION_HEADER (*PIMAGE_SECTION_HEADERS)[1];

// 计算对齐后的大小
unsigned long GetAlignedSize(unsigned long Origin, unsigned long Alignment)
{
return (Origin + Alignment - 1) / Alignment * Alignment;
}

// 计算加载pe并对齐需要占用多少内存
// 未直接使用OptionalHeader.SizeOfImage作为结果是因为据说有的编译器生成的exe这个值会填0
unsigned long CalcTotalImageSize(PIMAGE_DOS_HEADER MzH, unsigned long FileLen,
PIMAGE_NT_HEADERS peH, PIMAGE_SECTION_HEADERS peSecH)
{
unsigned long res;
// 计算pe头的大小
res = GetAlignedSize(peH->OptionalHeader.SizeOfHeaders, peH->OptionalHeader.SectionAlignment);
// 计算所有节的大小
for(int i=0; i < peH->FileHeader.NumberOfSections; ++i)
{
if(peSecH[i]->PointerToRawData + peSecH[i]->SizeOfRawData>FileLen){// 超出文件范围
return 0;
}
else if(peSecH[i]->VirtualAddress){//计算对齐后某节的大小
if(peSecH[i]->Misc.VirtualSize){
res = GetAlignedSize(peSecH[i]->VirtualAddress + peSecH[i]->Misc.VirtualSize,
peH->OptionalHeader.SectionAlignment);
}
else{
res = GetAlignedSize(peSecH[i]->VirtualAddress + peSecH[i]->SizeOfRawData,
peH->OptionalHeader.SectionAlignment);
}
}
else if(peSecH[i]->Misc.VirtualSize < peSecH[i]->SizeOfRawData){
res += GetAlignedSize(peSecH[i]->SizeOfRawData, peH->OptionalHeader.SectionAlignment);
}
else{
res += GetAlignedSize(peSecH[i]->Misc.VirtualSize, peH->OptionalHeader.SectionAlignment);
}
}
return res;
}
// 加载pe到内存并对齐所有节
BOOL AlignPEToMem(void *Buf, long Len, PIMAGE_NT_HEADERS &peH, PIMAGE_SECTION_HEADERS &peSecH,
void *&Mem, unsigned long &ImageSize)
{
PIMAGE_DOS_HEADER SrcMz; // DOS头
PIMAGE_NT_HEADERS SrcPeH; // PE头
PIMAGE_SECTION_HEADERS SrcPeSecH; // 节表

SrcMz = (PIMAGE_DOS_HEADER)Buf;
if(Len < sizeof(IMAGE_DOS_HEADER)) return FALSE;
if(SrcMz->e_magic != IMAGE_DOS_SIGNATURE) return FALSE;
if(Len < SrcMz->e_lfanew + (long)sizeof(IMAGE_NT_HEADERS)) return FALSE;
SrcPeH = (PIMAGE_NT_HEADERS)((int)SrcMz + SrcMz->e_lfanew);
if(SrcPeH->Signature != IMAGE_NT_SIGNATURE) return FALSE;
if((SrcPeH->FileHeader.Characteristics & IMAGE_FILE_DLL)
|| (SrcPeH->FileHeader.Characteristics & IMAGE_FILE_EXECUTABLE_IMAGE == 0)
|| (SrcPeH->FileHeader.SizeOfOptionalHeader != sizeof(IMAGE_OPTIONAL_HEADER))) return FALSE;
SrcPeSecH = (PIMAGE_SECTION_HEADERS)((int)SrcPeH + sizeof(IMAGE_NT_HEADERS));
ImageSize = CalcTotalImageSize(SrcMz, Len, SrcPeH, SrcPeSecH);
if(ImageSize == 0) return FALSE;
Mem = VirtualAlloc(NULL, ImageSize, MEM_COMMIT, PAGE_EXECUTE_READWRITE); // 分配内存
if(Mem){
// 计算需要复制的PE头字节数
unsigned long l = SrcPeH->OptionalHeader.SizeOfHeaders;
for(int i=0; i < SrcPeH->FileHeader.NumberOfSections; ++i)
if((SrcPeSecH[i]->PointerToRawData) && (SrcPeSecH[i]->PointerToRawData < l))
l = SrcPeSecH[i]->PointerToRawData;
memmove(Mem, SrcMz, l);
peH = (PIMAGE_NT_HEADERS)((int)Mem + ((PIMAGE_DOS_HEADER)Mem)->e_lfanew);
peSecH = (PIMAGE_SECTION_HEADERS)((int)peH + sizeof(IMAGE_NT_HEADERS));
void *Pt = (void *)((unsigned long)Mem + GetAlignedSize(peH->OptionalHeader.SizeOfHeaders, peH->OptionalHeader.SectionAlignment));
for(i=0; i < peH->FileHeader.NumberOfSections; ++i)
{
// 定位该节在内存中的位置
if(peSecH[i]->VirtualAddress)
Pt = (void *)((unsigned long)Mem + peSecH[i]->VirtualAddress);
if(peSecH[i]->SizeOfRawData){
// 复制数据到内存
memmove(Pt, (const void *)((unsigned long)(SrcMz) + peSecH[i]->PointerToRawData), peSecH[i]->SizeOfRawData);
if(peSecH[i]->Misc.VirtualSize < peSecH[i]->SizeOfRawData)
Pt = (void *)((unsigned long)Pt + GetAlignedSize(peSecH[i]->SizeOfRawData, peH->OptionalHeader.SectionAlignment));
else // pt 定位到下一节开始位置
Pt = (void *)((unsigned long)Pt + GetAlignedSize(peSecH[i]->Misc.VirtualSize, peH->OptionalHeader.SectionAlignment));
}
else{
Pt = (void *)((unsigned long)Pt + GetAlignedSize(peSecH[i]->Misc.VirtualSize, peH->OptionalHeader.SectionAlignment));
}
}
}
return TRUE;
}

typedef void *(__stdcall *pfVirtualAllocEx)(unsigned long, void *, unsigned long, unsigned long, unsigned long);
pfVirtualAllocEx MyVirtualAllocEx = NULL;

BOOL IsNT()
{
return MyVirtualAllocEx!=NULL;
}

// 生成外壳程序命令行
char *PrepareShellExe(char *CmdParam, unsigned long BaseAddr, unsigned long ImageSize)
{
if(IsNT()){
char *Buf = new char[256];
memset(Buf, 0, 256);
GetModuleFileName(0, Buf, 256);
strcat(Buf, CmdParam);
return Buf; // 请记得释放内存;-)
}
else{
// Win98下的处理请参考原文;-)
// http://community.csdn.net/Expert/topic/4416/4416252.xml?temp=8.709133E-03
return NULL;
}
}

// 是否包含可重定向列表
BOOL HasRelocationTable(PIMAGE_NT_HEADERS peH)
{
return (peH->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_BASERELOC].VirtualAddress)
&& (peH->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_BASERELOC].Size);
}


#pragma pack(push, 1)
typedef struct{
unsigned long VirtualAddress;
unsigned long SizeOfBlock;
} *PImageBaseRelocation;
#pragma pack(pop)

// 重定向PE用到的地址
void DoRelocation(PIMAGE_NT_HEADERS peH, void *OldBase, void *NewBase)
{
unsigned long Delta = (unsigned long)NewBase - peH->OptionalHeader.ImageBase;
PImageBaseRelocation p = (PImageBaseRelocation)((unsigned long)OldBase
+ peH->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_BASERELOC].VirtualAddress);
while(p->VirtualAddress + p->SizeOfBlock)
{
unsigned short *pw = (unsigned short *)((int)p + sizeof(*p));
for(unsigned int i=1; i <= (p->SizeOfBlock - sizeof(*p)) / 2; ++i)
{
if((*pw) & 0xF000 == 0x3000){
unsigned long *t = (unsigned long *)((unsigned long)(OldBase) + p->VirtualAddress + ((*pw) & 0x0FFF));
*t += Delta;
}
++pw;
}
p = (PImageBaseRelocation)pw;
}
}

// 卸载原外壳占用内存
BOOL UnloadShell(HANDLE ProcHnd, unsigned long BaseAddr)
{
typedef unsigned long (__stdcall *pfZwUnmapViewOfSection)(unsigned long, unsigned long);
pfZwUnmapViewOfSection ZwUnmapViewOfSection = NULL;
BOOL res = FALSE;
HMODULE m = LoadLibrary("ntdll.dll");
if(m){
ZwUnmapViewOfSection = (pfZwUnmapViewOfSection)GetProcAddress(m, "ZwUnmapViewOfSection");
if(ZwUnmapViewOfSection)
res = (ZwUnmapViewOfSection((unsigned long)ProcHnd, BaseAddr) == 0);
FreeLibrary(m);
}
return res;
}

// 创建外壳进程并获取其基址、大小和当前运行状态
BOOL CreateChild(char *Cmd, CONTEXT &Ctx, HANDLE &ProcHnd, HANDLE &ThrdHnd,
unsigned long &ProcId, unsigned long &BaseAddr, unsigned long &ImageSize)
{
STARTUPINFOA si;
PROCESS_INFORMATION pi;
unsigned long old;
MEMORY_BASIC_INFORMATION MemInfo;
memset(&si, 0, sizeof(si));
memset(&pi, 0, sizeof(pi));
si.cb = sizeof(si);

BOOL res = CreateProcess(NULL, Cmd, NULL, NULL, FALSE, CREATE_SUSPENDED, NULL, NULL, &si, &pi); // 以挂起方式运行进程;
if(res){
ProcHnd = pi.hProcess;
ThrdHnd = pi.hThread;
ProcId = pi.dwProcessId;
// 获取外壳进程运行状态，[ctx.Ebx+8]内存处存的是外壳进程的加载基址，ctx.Eax存放有外壳进程的入口地址
Ctx.ContextFlags = CONTEXT_FULL;
GetThreadContext(ThrdHnd, &Ctx);
ReadProcessMemory(ProcHnd, (void *)(Ctx.Ebx+8), &BaseAddr, sizeof(unsigned long), &old); // 读取加载基址
void *p = (void *)BaseAddr;
// 计算外壳进程占有的内存
while(VirtualQueryEx(ProcHnd, p, &MemInfo, sizeof(MemInfo)))
{
if(MemInfo.State = MEM_FREE) break;
p = (void *)((unsigned long)p + MemInfo.RegionSize);
}
ImageSize = (unsigned long)p - (unsigned long)BaseAddr;
}
return res;
}

// 创建外壳进程并用目标进程替换它然后执行
HANDLE AttachPE(char *CmdParam, PIMAGE_NT_HEADERS peH, PIMAGE_SECTION_HEADERS peSecH,
void *Ptr, unsigned long ImageSize, unsigned long &ProcId)
{
HANDLE res = INVALID_HANDLE_VALUE;
CONTEXT Ctx;
HANDLE Thrd;
unsigned long Addr, Size;
char *s = PrepareShellExe(CmdParam, peH->OptionalHeader.ImageBase, ImageSize);
if(s==NULL) return res;
if(CreateChild(s, Ctx, res, Thrd, ProcId, Addr, Size)){
void *p = NULL;
unsigned long old;
if((peH->OptionalHeader.ImageBase == Addr) && (Size >= ImageSize)){// 外壳进程可以容纳目标进程并且加载地址一致
p = (void *)Addr;
VirtualProtectEx(res, p, Size, PAGE_EXECUTE_READWRITE, &old);
}
else if(IsNT()){
if(UnloadShell(res, Addr)){// 卸载外壳进程占有内存
p = MyVirtualAllocEx((unsigned long)res, (void *)peH->OptionalHeader.ImageBase, ImageSize, MEM_RESERVE | MEM_COMMIT, PAGE_EXECUTE_READWRITE);
}
if((p == NULL) && HasRelocationTable(peH)){// 分配内存失败并且目标进程支持重定向
p = MyVirtualAllocEx((unsigned long)res, NULL, ImageSize, MEM_RESERVE | MEM_COMMIT, PAGE_EXECUTE_READWRITE);
if(p) DoRelocation(peH, Ptr, p); // 重定向
}
}
if(p){
WriteProcessMemory(res, (void *)(Ctx.Ebx+8), &p, sizeof(DWORD), &old); // 重置目标进程运行环境中的基址
peH->OptionalHeader.ImageBase = (unsigned long)p;
if(WriteProcessMemory(res, p, Ptr, ImageSize, &old)){// 复制PE数据到目标进程
Ctx.ContextFlags = CONTEXT_FULL;
if((unsigned long)p == Addr)
Ctx.Eax = peH->OptionalHeader.ImageBase + peH->OptionalHeader.AddressOfEntryPoint; // 重置运行环境中的入口地址
else
Ctx.Eax = (unsigned long)p + peH->OptionalHeader.AddressOfEntryPoint;
SetThreadContext(Thrd, &Ctx); // 更新运行环境
ResumeThread(Thrd); // 执行
CloseHandle(Thrd);
}
else{// 加载失败,杀掉外壳进程
TerminateProcess(res, 0);
CloseHandle(Thrd);
CloseHandle(res);
res = INVALID_HANDLE_VALUE;
}
}
else{// 加载失败,杀掉外壳进程
TerminateProcess(res, 0);
CloseHandle(Thrd);
CloseHandle(res);
res = INVALID_HANDLE_VALUE;
}
}
delete[] s;
return res;
}

/*******************************************************/
{ ******************************************************* }
{ * 从内存中加载并运行exe * }
{ ******************************************************* }
{ * 参数： }
{ * Buffer: 内存中的exe地址 }
{ * Len: 内存中exe占用长度 }
{ * CmdParam: 命令行参数(不包含exe文件名的剩余命令行参数）}
{ * ProcessId: 返回的进程Id }
{ * 返回值： 如果成功则返回进程的Handle(ProcessHandle), }
{ 如果失败则返回INVALID_HANDLE_VALUE }
{ ******************************************************* }
/*******************************************************/
HANDLE MemExecute(void *ABuffer, long Len, char *CmdParam, unsigned long *ProcessId)
{
HANDLE res = INVALID_HANDLE_VALUE;
PIMAGE_NT_HEADERS peH;
PIMAGE_SECTION_HEADERS peSecH;
void *Ptr;
unsigned long peSz;
if(AlignPEToMem(ABuffer, Len, peH, peSecH, Ptr, peSz)){
res = AttachPE(CmdParam, peH, peSecH, Ptr, peSz, *ProcessId);
VirtualFree(Ptr, peSz, MEM_DECOMMIT);
}
return res;
}

// 初始化
class CInit
{
public:
CInit(){
MyVirtualAllocEx = (pfVirtualAllocEx)GetProcAddress(GetModuleHandle("Kernel32.dll"), "VirtualAllocEx");
}
}Init;


下面是一段简单的测试程序：）

CFile f;
if(f.Open("target.exe", CFile::modeRead)){
void *lpBuf = new char[f.GetLength()];
f.Read(lpBuf, f.GetLength());
unsigned long ProcessId;
HANDLE MemExecute(void *, long, char *, unsigned long *);
MemExecute(lpBuf, f.GetLength(), "", &ProcessId);
f.Close();
delete[] lpBuf;
}