public void InstallBreakPoint(ulong startAddress) {
//const byte INT3Trap = 0xCC;
/*if (CheckBreakPointActive()) {
throw new Exception("only one breakpoint at a time supported");
}*/
LoggerInstance.WriteLine($"installing breakpoint at {startAddress:X}");
if (BreakPoints[startAddress].OriginalCode == null) {
byte[] mem = DebugProcessUtils.ReadBytes(CurrentProcess, startAddress, AssemblyUtil.InfiniteLoop.Length);
BreakPoints[startAddress].OriginalCode = mem;
}
DebugProcessUtils.WriteBytes(CurrentProcess, startAddress, AssemblyUtil.InfiniteLoop);
BreakPoints[startAddress].IsSoftware = true;
BreakPoints[startAddress].IsActive = true;
}
private void UninstallBreakPoint(ulong address) {
if (BreakPoints[address].IsActive) {
if (BreakPoints[address].IsSoftware) {
byte[] mem = DebugProcessUtils.ReadBytes(CurrentProcess, address, AssemblyUtil.InfiniteLoop.Length);
if (mem[0] == AssemblyUtil.InfiniteLoop[0] && mem[1] == AssemblyUtil.InfiniteLoop[1]) {
LoggerInstance.WriteLine($"{nameof(UninstallBreakPoint)}: restoring inf-jmp with original code at 0x{address:X}");
DebugProcessUtils.WriteBytes(CurrentProcess, address, BreakPoints[address].OriginalCode);
}
else if (mem[0] != BreakPoints[address].OriginalCode[0] && mem[1] != BreakPoints[address].OriginalCode[1]) {
LoggerInstance.WriteLine($"{nameof(UninstallBreakPoint)}: code changed (self-modifying?) at 0x{address:X}");
}
else {
LoggerInstance.WriteLine($"{nameof(UninstallBreakPoint)}: code was intact at 0x{address:X}");
}
} else if (BreakPoints[address].IsHardware && BreakPoints[address].HardwareBreakPointHandle != 0) {
RemoveHardwareBreakpoint(BreakPoints[address].HardwareBreakPointHandle);
/*foreach (ProcessThread thread in CurrentProcess.Threads) {
setHardwareBreakPoint((uint)thread.Id, address, true, true);
}*/
}
}
BreakPoints[address].IsActive = false;
}
public static TraceState InstallTracer(Process process, ulong patchSite, Logger logger, byte[] asmSizes, ImportResolver ir)
{
var processHandle = Win32Imports.OpenProcess(Win32Imports.ProcessAccessFlags.All, false, process.Id);
var traceState = new TraceState();
if ((ulong)processHandle == 0)
{
logger.WriteLine("could not open process");
return(null);
}
const int patchSiteSize = 24;
const int codeSize = 1024;
const int traceLogSize = 1024;
var originalCode = DebugProcessUtils.ReadBytes(process, (ulong)process.MainModule.BaseAddress, process.MainModule.ModuleMemorySize);
var originalCodeAddress = Win32Imports.VirtualAllocEx(
processHandle,
new IntPtr(0),
new IntPtr(originalCode.Length),
Win32Imports.AllocationType.Commit | Win32Imports.AllocationType.Reserve,
Win32Imports.MemoryProtection.ReadWrite);
if ((ulong)originalCodeAddress == 0)
{
logger.WriteLine($"could not allocate memory for {nameof(originalCodeAddress)}");
return(null);
}
var traceLogAddress = Win32Imports.VirtualAllocEx(
processHandle,
new IntPtr(0),
new IntPtr(traceLogSize),
Win32Imports.AllocationType.Commit | Win32Imports.AllocationType.Reserve,
Win32Imports.MemoryProtection.ReadWrite);
if ((ulong)traceLogAddress == 0)
{
logger.WriteLine($"could not allocate memory for {nameof(traceLogAddress)}");
return(null);
}
var injectedCodeAddress = Win32Imports.VirtualAllocEx(
processHandle,
new IntPtr(0),
new IntPtr(codeSize),
Win32Imports.AllocationType.Commit | Win32Imports.AllocationType.Reserve,
Win32Imports.MemoryProtection.ExecuteReadWrite);
if ((ulong)injectedCodeAddress == 0)
{
logger.WriteLine($"could not allocate memory for {nameof(injectedCodeAddress)}");
return(null);
}
var asmSizesAddress = Win32Imports.VirtualAllocEx(
processHandle,
new IntPtr(0),
new IntPtr(asmSizes.Length),
Win32Imports.AllocationType.Commit | Win32Imports.AllocationType.Reserve,
Win32Imports.MemoryProtection.ReadWrite);
if ((ulong)asmSizesAddress == 0)
{
logger.WriteLine($"could not allocate memory for {nameof(asmSizesAddress)}");
return(null);
}
traceState.CodeAddress = (ulong)injectedCodeAddress;
traceState.TraceLogAddress = (ulong)traceLogAddress;
int addrSize = Marshal.SizeOf(typeof(IntPtr));
var c1 = Assembler.CreateContext <Action>();
// save rax
c1.Push(c1.Rax);
// push return address
c1.Lea(c1.Rax, Memory.QWord(CodeContext.Rip, -addrSize));
c1.Push(c1.Rax);
// push "call" address
c1.Mov(c1.Rax, (ulong)injectedCodeAddress);
c1.Push(c1.Rax);
// "call" codeAddress
c1.Ret();
c1.Nop();
c1.Nop();
c1.Nop();
var patchSiteCodeJit = AssemblyUtil.GetAsmJitBytes(c1);
Debug.Assert(patchSiteCodeJit.Length == patchSiteSize, "patch site size incorrect");
var c = Assembler.CreateContext <Action>();
c.Push(c.Rbp);
c.Mov(c.Rbp, c.Rsp);
c.Pushf();
c.Push(c.Rbx);
c.Push(c.Rcx);
c.Push(c.Rdx);
// log thread id
var getThreadContext = ir.LookupFunction("KERNEL32.DLL:GetCurrentThreadId");
//c.Call(getThreadContext);
c.Lea(c.Rax, Memory.QWord(CodeContext.Rip, 13)); // skips next instructions
c.Push(c.Rax);
c.Mov(c.Rax, getThreadContext);
c.Push(c.Rax);
c.Ret();
c.Mov(c.Rbx, (ulong)traceLogAddress);
c.Mov(Memory.Word(c.Rbx), c.Eax);
// reserve space for instruction counter, the 01-08 is just so AsmJit doesn't shorten the instruction
// we overwrite the value to 0 later on
c.Mov(c.Rax, (ulong)0x0102030405060708);
var smcLastRipJit = AssemblyUtil.GetAsmJitBytes(c).Length - addrSize;
c.Lea(c1.Rax, Memory.QWord(CodeContext.Rip, -7 - addrSize));
c.Mov(c.Rcx, Memory.QWord(c.Rax));
c.Inc(c.Rcx);
c.Xchg(Memory.QWord(c.Rax), c.Rcx);
// find return address and store size of instruction at return address in rcx
c.Mov(c.Rdx, Memory.QWord(c.Rbp, addrSize));
c.Mov(c.Rbx, c.Rdx);
c.Mov(c.Rax, (ulong)process.MainModule.BaseAddress);
c.Sub(c.Rdx, c.Rax);
c.Mov(c.Rax, (ulong)asmSizesAddress);
c.Add(c.Rdx, c.Rax);
c.Movzx(c.Rcx, Memory.Byte(c.Rdx));
// RESTORE ORIGINAL CODE
// get address of original code in Rdx
c.Mov(c.Rdx, c.Rbx);
c.Mov(c.Rax, (ulong)process.MainModule.BaseAddress);
c.Sub(c.Rdx, c.Rax);
// TODO: compare Rdx with process.MainModule.ModuleMemorySize - patchSiteSize and abort if greater
c.Mov(c.Rax, (ulong)originalCodeAddress);
c.Add(c.Rdx, c.Rax);
// restore call site 1
c.Mov(c.Rax, Memory.QWord(c.Rdx));
c.Mov(Memory.QWord(c.Rbx), c.Rax);
// restore call site 2
c.Mov(c.Rax, Memory.QWord(c.Rdx, addrSize));
c.Mov(Memory.QWord(c.Rbx, addrSize), c.Rax);
// restore call site 3
c.Mov(c.Rax, Memory.QWord(c.Rdx, addrSize * 2));
c.Mov(Memory.QWord(c.Rbx, addrSize * 2), c.Rax);
// CLEAN UP AND RETURN
// put new patch in place
// add instruction size to return address, so we write patch at next instruction
c.Add(c.Rbx, c.Rcx);
// restore patch site 1
c.Mov(c.Rax, BitConverter.ToUInt64(patchSiteCodeJit, 0));
c.Mov(Memory.QWord(c.Rbx), c.Rax);
// restore patch site 2
c.Mov(c.Rax, BitConverter.ToUInt64(patchSiteCodeJit, addrSize));
c.Mov(Memory.QWord(c.Rbx, addrSize), c.Rax);
// restore patch site 3
c.Mov(c.Rax, BitConverter.ToUInt64(patchSiteCodeJit, addrSize * 2));
c.Mov(Memory.QWord(c.Rbx, addrSize * 2), c.Rax);
// end put new patch in place
// restore rax from call site
c.Mov(c.Rax, Memory.QWord(c.Rbp, 2 * addrSize));
c.Pop(c.Rdx);
c.Pop(c.Rcx);
c.Pop(c.Rbx);
c.Popf();
c.Pop(c.Rbp);
c.Ret((ulong)8);
// overwrite some pieces of the code with values computed later on
var codeSiteCodeJit = AssemblyUtil.GetAsmJitBytes(c);
for (var j = 0; j < 8; j++)
{
codeSiteCodeJit[smcLastRipJit + j] = 0;
}
var i = 0;
var nextOffset1 = 0;
using (var sw = new StreamWriter(Specifics.PatchAsmDumpFileName)) {
foreach (var s in codeSiteCodeJit.Select((b1) => $"b: 0x{b1:X2}"))
{
string asm1S;
try {
var asm1 = AssemblyUtil.Disassemble(codeSiteCodeJit.Skip(i).Take(AssemblyUtil.MaxInstructionBytes).ToArray());
asm1S = i == nextOffset1?asm1.ToString() : "";
if (i == nextOffset1)
{
nextOffset1 += asm1.Length;
}
}
catch (DecodeException) {
asm1S = "failed";
}
sw.WriteLine($"{s}: ASM: {asm1S}");
i++;
}
}
if (codeSiteCodeJit.Length > codeSize)
{
throw new Exception("did not reserve enough memory for code");
}
// write process memory
DebugProcessUtils.WriteBytes(process, (ulong)originalCodeAddress, originalCode);
DebugProcessUtils.WriteBytes(process, (ulong)asmSizesAddress, asmSizes);
DebugProcessUtils.WriteBytes(process, (ulong)injectedCodeAddress, codeSiteCodeJit);
DebugProcessUtils.WriteBytes(process, patchSite, patchSiteCodeJit);
return(traceState);
}
public bool ResumeBreak(bool trace = true) {
//Console.WriteLine("ResumeBreak");
//for (var i = 0; i < 10000; i++) {
var done = false;
var goNextBreakPoint = false;
var continueCode = Win32Imports.DbgContinue;
while (!done)
{
Win32Imports.DebugEvent evt;
if (!Win32Imports.WaitForDebugEvent(out evt, 0)) {
//if (!handleDebugEvent(out evt, out continueCode)) {
//Console.WriteLine("WaitForDebugEvent failed");
//throw new Win32Exception();
done = true;
}
else {
CurrentInfo.EventCount++;
// Multiple if's for easier debugging at this moment
switch (evt.dwDebugEventCode) {
case Win32Imports.DebugEventType.LoadDllDebugEvent:
//Console.WriteLine($"resumed load dll event: {evt.dwThreadId}");
break;
case Win32Imports.DebugEventType.UnloadDllDebugEvent:
//Console.WriteLine($"resumed unload dll event: {evt.dwThreadId}");
break;
case Win32Imports.DebugEventType.ExceptionDebugEvent:
var exceptionAddress = (ulong) evt.Exception.ExceptionRecord.ExceptionAddress.ToInt64();
//Console.WriteLine($"first addr: {breakAddress:X} vs {address:X}");
var context = new Win32Imports.ContextX64();
var breakAddress = getRip((uint) evt.dwThreadId, ref context, GetRipAction.ActionGetContext);
var code = evt.Exception.ExceptionRecord.ExceptionCode;
//Console.WriteLine($"code: {code}, events: {eventCount}, thread: {evt.dwThreadId}, addr: {breakAddress2:X} vs {address:X}");
if (BreakPoints.ContainsKey(breakAddress) && BreakPoints[breakAddress].IsActive) {
LoggerInstance.WriteLine($"match at {breakAddress:X}, trace: {trace}");
setTrace((uint)evt.dwThreadId);
UninstallBreakPoint(breakAddress);
_lastBreakAddress = breakAddress;
CurrentInfo.LastContext = context;
CurrentInfo.LastContextReady = true;
// trace
//setTrace((uint) evt.dwThreadId, false);
if (BreakPoints[breakAddress].Description.Equals(CloseHandleDescription)) {
LoggerInstance.WriteLine("CloseHandle hit");
LoggerInstance.WriteLine("Registers:" + AssemblyUtil.FormatContext(context));
} else {
}
done = BreakPointCallBack(this, evt.dwThreadId, context, trace).StepOver;
goNextBreakPoint = done;
//} else if (!CheckBreakPointActive()) {
}
else {
// if we have seen it before
var shouldTrace = !BreakPoints.ContainsKey(breakAddress) ||
!(BreakPoints.ContainsKey(breakAddress) && !BreakPoints[breakAddress].ShouldEnable) ||
!(BreakPoints.ContainsKey(breakAddress) && !BreakPoints[breakAddress].IsActive);
// no breakpoint active, so we are tracing
if (trace && shouldTrace) {
LoggerInstance.WriteLine($"tracing thread {evt.dwThreadId} at 0x{breakAddress:X}");
var ret = BreakPointCallBack(this, evt.dwThreadId, context, true);
done = ret.StepOver;
goNextBreakPoint = done;
if (ret.Ignore) {
LoggerInstance.WriteLine("continuing with exception handlers");
continueCode = Win32Imports.DbgExceptionNotHandled;
}
}
else {
LoggerInstance.WriteLine("continuing with exception handlers");
continueCode = Win32Imports.DbgExceptionNotHandled;
}
}
Instruction instr = null;
string asm = "N/A";
string asm2 = "N/A";
try {
instr = AssemblyUtil.Disassemble(CurrentProcess, exceptionAddress);
asm = AssemblyUtil.FormatInstruction(AssemblyUtil.Disassemble(CurrentProcess, breakAddress));
asm2 = AssemblyUtil.FormatInstruction(AssemblyUtil.Disassemble(CurrentProcess, exceptionAddress));
}
catch (Exception)
{
// ignored
}
string msg;
switch (code) {
case Win32Imports.ExceptionCodeStatus.ExceptionSingleStep:
asm = AssemblyUtil.FormatInstruction(AssemblyUtil.Disassemble(CurrentProcess, breakAddress));
LoggerInstance.WriteLine($"single step at {breakAddress:X}, evtCount: {CurrentInfo.EventCount}, asm: {asm}");
continueCode = HasBreakPoint(breakAddress) ? Win32Imports.DbgContinue : Win32Imports.DbgExceptionNotHandled;
break;
case Win32Imports.ExceptionCodeStatus.ExceptionBreakpoint:
asm = AssemblyUtil.FormatInstruction(instr);
//if (instr.Mnemonic.Equals("INT") && instr.Operands.Equals("3")) {
if (instr != null && instr.Mnemonic == ud_mnemonic_code.UD_Iint3) {
LoggerInstance.WriteLine($"int3 breakpoint at: {exceptionAddress:X}, evtCount: {CurrentInfo.EventCount}, asm: {asm}");
LoggerInstance.WriteLine("overwriting with NOP");
DebugProcessUtils.WriteByte(CurrentProcess, exceptionAddress, AssemblyUtil.Nop);
continueCode = Win32Imports.DbgContinue;
} else {
msg = $"breakpoint, chance: { evt.Exception.dwFirstChance}";
msg += $", at: 0x{breakAddress:X}, exc at: 0x{exceptionAddress:X}, asm: {asm}, exc asm: {asm2}";
LoggerInstance.WriteLine(msg);
}
break;
case Win32Imports.ExceptionCodeStatus.ExceptionInvalidHandle:
msg = $"invalid handle, chance: { evt.Exception.dwFirstChance}";
msg += $", at: 0x{breakAddress:X}, exc at: 0x{exceptionAddress:X}, asm: {asm}, exc asm: {asm2}";
LoggerInstance.WriteLine(msg);
LoggerInstance.WriteLine(msg);
AssemblyUtil.LogStackTrace(_importResolver, LoggerInstance, CurrentProcess, context.Rsp);
continueCode = Win32Imports.DbgExceptionNotHandled;
break;
case Win32Imports.ExceptionCodeStatus.ExceptionInvalidOperation:
msg = $"invalid operation, chance: { evt.Exception.dwFirstChance}";
msg += $", at: 0x{breakAddress:X}, exc at: 0x{exceptionAddress:X}, asm: {asm}, exc asm: {asm2}";
// anti-anti-debug measure
if (instr != null && instr.Mnemonic == ud_mnemonic_code.UD_Iud2) {
LoggerInstance.WriteLine("overwriting UD2 with NOP");
DebugProcessUtils.WriteBytes(CurrentProcess, exceptionAddress, new[] { AssemblyUtil.Nop, AssemblyUtil.Nop });
}
// anti-anti-debug measure
var instr2 = AssemblyUtil.Disassemble(CurrentProcess, exceptionAddress - 1);
if (instr2.Mnemonic == ud_mnemonic_code.UD_Iint && instr2.Operands[0].Value == 0x2D) {
ulong rip = context.Rip - 1;
setRip((uint) evt.dwThreadId, false, rip);
LoggerInstance.WriteLine("INT2D encountered, subtracting 1 from Rip");
continueCode = Win32Imports.DbgContinue;
} else {
continueCode = Win32Imports.DbgExceptionNotHandled;
}
LoggerInstance.WriteLine(msg);
break;
case Win32Imports.ExceptionCodeStatus.ExceptionAccessViolation:
msg = $"access violation: {code:X}, chance: { evt.Exception.dwFirstChance}";
msg += $", at: 0x{breakAddress:X}, exc at: 0x{exceptionAddress:X}, asm: {asm}, exc asm: {asm2}";
LoggerInstance.WriteLine(msg);
break;
case 0:
LoggerInstance.WriteLine($"event 0 at: {breakAddress:X}");
break;
default:
msg = $"unknown code: {code:X}, chance: { evt.Exception.dwFirstChance}";
msg += $", at: 0x{breakAddress:X}, exc at: 0x{exceptionAddress:X}, asm: {asm}, exc asm: {asm2}";
LoggerInstance.WriteLine(msg);
break;
}
break;
case Win32Imports.DebugEventType.CreateProcessDebugEvent:
//Console.WriteLine($"resumed create process event for thread {evt.dwThreadId}");
break;
case Win32Imports.DebugEventType.CreateThreadDebugEvent:
//Console.WriteLine($"resumed create thread event for thread {evt.dwThreadId}");
break;
case Win32Imports.DebugEventType.ExitThreadDebugEvent:
//Console.WriteLine($"resumed exit thread event for thread {evt.dwThreadId}");
break;
case Win32Imports.DebugEventType.ExitProcessDebugEvent:
Console.WriteLine($"resumed exit process event for thread {evt.dwThreadId}");
break;
default:
Console.WriteLine($"resumed debug event for thread: {evt.dwThreadId} {evt.dwDebugEventCode}");
break;
}
//LoggerInstance.WriteLine($"debug event of type {evt.dwDebugEventCode}");
if (!Win32Imports.ContinueDebugEvent(evt.dwProcessId, evt.dwThreadId, continueCode)) {
throw new Win32Exception();
}
//ContinueDebugEvent(evt.dwProcessId, evt.dwThreadId, DBG_EXCEPTION_NOT_HANDLED);
//setBreakPoint((uint) evt.dwThreadId, address, false);
}
}
//Console.WriteLine("End ResumeBreak");
//return events;
return goNextBreakPoint;
}
public static void InstallTracer(Process process, ulong patchSite, Logger logger)
{
var processHandle = Win32Imports.OpenProcess(Win32Imports.ProcessAccessFlags.All, false, process.Id);
var retVal = new TraceState();
if ((ulong)processHandle == 0)
{
logger.WriteLine("could not open process");
return;
}
const int patchSiteSize = 24;
const int patchAreaSize = 100;
const int codeSize = 1024 + patchAreaSize * 100;
var originalCode = DebugProcessUtils.ReadBytes(process, patchSite, patchAreaSize);
// minus patchSiteSize because we need to restore patchSiteSize bytes
var ci = new diStorm.CodeInfo(0, originalCode.Take(patchAreaSize - patchSiteSize).ToArray(), diStorm.DecodeType.Decode64Bits, 0);
var dr = new diStorm.DecodedResult(patchAreaSize);
diStorm.diStorm3.Decode(ci, dr);
var decodedInstructions = dr.Instructions;
var bogusAddress = Win32Imports.VirtualAllocEx(
processHandle,
new IntPtr(0),
new IntPtr(patchSiteSize * 2),
Win32Imports.AllocationType.Commit | Win32Imports.AllocationType.Reserve,
Win32Imports.MemoryProtection.ReadWrite);
var codeAddress = Win32Imports.VirtualAllocEx(
processHandle,
new IntPtr(0),
new IntPtr(codeSize),
Win32Imports.AllocationType.Commit | Win32Imports.AllocationType.Reserve,
Win32Imports.MemoryProtection.ExecuteReadWrite);
retVal.CodeAddress = (ulong)codeAddress;
if ((ulong)codeAddress == 0)
{
logger.WriteLine("could not allocate memory");
return;
}
var patchSiteCode = new byte[patchSiteSize];
var codeSiteCode = new byte[codeSize];
var patchPtr = 0;
var ptr = 0;
//patchSiteCode[patchPtr++] = 0xCC;
// push rax, see RESTORE_RAX
patchSiteCode[patchPtr++] = 0x50;
// lea rax, [rip-8]
patchSiteCode[patchPtr++] = 0x48;
patchSiteCode[patchPtr++] = 0x8D;
patchSiteCode[patchPtr++] = 0x05;
patchSiteCode[patchPtr++] = 0xF8;
patchSiteCode[patchPtr++] = 0xFF;
patchSiteCode[patchPtr++] = 0xFF;
patchSiteCode[patchPtr++] = 0xFF;
// push rax (rip)
patchSiteCode[patchPtr++] = 0x50;
// mov rax, constant
patchSiteCode[patchPtr++] = 0x48;
patchSiteCode[patchPtr++] = 0xB8;
foreach (var b in BitConverter.GetBytes((ulong)codeAddress))
{
patchSiteCode[patchPtr++] = b;
}
// push rax
patchSiteCode[patchPtr++] = 0x50;
// ret
patchSiteCode[patchPtr++] = 0xC3;
patchPtr += 3;
if (patchPtr != patchSiteSize)
{
logger.WriteLine($"made a mistake: {patchPtr} != {patchSiteSize}");
return;
}
// push rbp
codeSiteCode[ptr++] = 0x55;
// mov rbp, rsp
codeSiteCode[ptr++] = 0x48;
codeSiteCode[ptr++] = 0x89;
codeSiteCode[ptr++] = 0xE5;
// push flags
codeSiteCode[ptr++] = 0x9C;
// push rbx
codeSiteCode[ptr++] = 0x53;
// push rcx
codeSiteCode[ptr++] = 0x51;
// push rdx
codeSiteCode[ptr++] = 0x52;
// reserve space for last Rip address
// mov rax, constant
codeSiteCode[ptr++] = 0x48;
codeSiteCode[ptr++] = 0xB8;
var smcLastRip = ptr;
ptr += 8;
// lea rax, [rip-7-8]
codeSiteCode[ptr++] = 0x48;
codeSiteCode[ptr++] = 0x8D;
codeSiteCode[ptr++] = 0x05;
codeSiteCode[ptr++] = 0xF1;
codeSiteCode[ptr++] = 0xFF;
codeSiteCode[ptr++] = 0xFF;
codeSiteCode[ptr++] = 0xFF;
// mov rcx, [rax]
codeSiteCode[ptr++] = 0x48;
codeSiteCode[ptr++] = 0x8B;
codeSiteCode[ptr++] = 0x08;
// inc rcx
codeSiteCode[ptr++] = 0x48;
codeSiteCode[ptr++] = 0xFF;
codeSiteCode[ptr++] = 0xC1;
// xchg [rax], rcx
codeSiteCode[ptr++] = 0x48;
codeSiteCode[ptr++] = 0x87;
codeSiteCode[ptr++] = 0x08;
// find return address
// mov rbx, [rbp+8]
codeSiteCode[ptr++] = 0x48;
codeSiteCode[ptr++] = 0x8B;
codeSiteCode[ptr++] = 0x5D;
codeSiteCode[ptr++] = 0x08;
// call pastEndCode
codeSiteCode[ptr++] = 0xE8;
var callPastEndCodeImmediate = ptr;
ptr += 4;
var callPastEndCodeBaseOffset = ptr;
// END FUNCTION
// put new patch in place
// mov rax, constant
codeSiteCode[ptr++] = 0x48;
codeSiteCode[ptr++] = 0xB8;
foreach (var b in patchSiteCode.Skip(0).Take(8))
{
codeSiteCode[ptr++] = b;
}
// restore patch site 1
// mov [rbx], rax
codeSiteCode[ptr++] = 0x48;
codeSiteCode[ptr++] = 0x89;
codeSiteCode[ptr++] = 0x03;
// mov rax, constant
codeSiteCode[ptr++] = 0x48;
codeSiteCode[ptr++] = 0xB8;
foreach (var b in patchSiteCode.Skip(8).Take(8))
{
codeSiteCode[ptr++] = b;
}
// restore patch site 2
// mov [rbx+8], rax
codeSiteCode[ptr++] = 0x48;
codeSiteCode[ptr++] = 0x89;
codeSiteCode[ptr++] = 0x43;
codeSiteCode[ptr++] = 0x08;
// mov rax, constant
codeSiteCode[ptr++] = 0x48;
codeSiteCode[ptr++] = 0xB8;
foreach (var b in patchSiteCode.Skip(16).Take(8))
{
codeSiteCode[ptr++] = b;
}
// restore patch site 3
// mov [rbx+16], rax
codeSiteCode[ptr++] = 0x48;
codeSiteCode[ptr++] = 0x89;
codeSiteCode[ptr++] = 0x43;
codeSiteCode[ptr++] = 0x10;
// end put new patch in place
// mov rax,[rbp+16]
codeSiteCode[ptr++] = 0x48;
codeSiteCode[ptr++] = 0x8B;
codeSiteCode[ptr++] = 0x45;
codeSiteCode[ptr++] = 0x10;
// pop rdx
codeSiteCode[ptr++] = 0x5A;
// pop rcx
codeSiteCode[ptr++] = 0x59;
// pop rbx
codeSiteCode[ptr++] = 0x5B;
// pop flags
codeSiteCode[ptr++] = 0x9D;
// pop rbp
codeSiteCode[ptr++] = 0x5D;
// ret 8
codeSiteCode[ptr++] = 0xC2;
codeSiteCode[ptr++] = 0x08;
codeSiteCode[ptr++] = 0x00;
codeSiteCode[callPastEndCodeImmediate] = (byte)(ptr - callPastEndCodeBaseOffset);
// imul rcx,rcx,constant
codeSiteCode[ptr++] = 0x48;
codeSiteCode[ptr++] = 0x6B;
codeSiteCode[ptr++] = 0xC9;
// = size of restore function
var multiplyImmediate = ptr;
codeSiteCode[ptr++] = 0x00;
// lea rcx, rcx+eax+constant
codeSiteCode[ptr++] = 0x48;
codeSiteCode[ptr++] = 0x8D;
codeSiteCode[ptr++] = 0x4C;
codeSiteCode[ptr++] = 0x08;
var leaRcxConstant = ptr;
codeSiteCode[ptr++] = 0x00;
// jmp rcx
codeSiteCode[ptr++] = 0xFF;
codeSiteCode[ptr++] = 0xE1;
codeSiteCode[leaRcxConstant] = (byte)(ptr - smcLastRip);
// restore function
uint offset = 0;
var lastReturn = 0;
foreach (var instr in decodedInstructions.Select((value, index) => new { Value = value, Index = index }))
{
var startOfRestore = ptr;
Console.WriteLine($"instruction {instr.Value.Mnemonic}, size: {instr.Value.Size}");
// reserve space for call site restore 1
// mov rax, constant
codeSiteCode[ptr++] = 0x48;
codeSiteCode[ptr++] = 0xB8;
var originalOffset = 0;
var patchOffset = 0;
foreach (var b in originalCode.Skip((int)offset).Take(8))
{
if (originalOffset < instr.Value.Size)
{
codeSiteCode[ptr++] = b;
}
else
{
codeSiteCode[ptr++] = patchSiteCode[patchOffset++];
}
originalOffset++;
}
// restore call site 1
// mov [rbx], rax
codeSiteCode[ptr++] = 0x48;
codeSiteCode[ptr++] = 0x89;
codeSiteCode[ptr++] = 0x03;
// reserve space for call site restore 2
// mov rax, constant
codeSiteCode[ptr++] = 0x48;
codeSiteCode[ptr++] = 0xB8;
foreach (var b in originalCode.Skip((int)offset + 8).Take(8))
{
if (originalOffset < instr.Value.Size)
{
codeSiteCode[ptr++] = b;
}
else
{
codeSiteCode[ptr++] = patchSiteCode[patchOffset++];
}
originalOffset++;
}
// restore call site 2
// mov [rbx+8], rax
codeSiteCode[ptr++] = 0x48;
codeSiteCode[ptr++] = 0x89;
codeSiteCode[ptr++] = 0x43;
codeSiteCode[ptr++] = 0x08;
// reserve space for call site restore 3
// mov rax, constant
codeSiteCode[ptr++] = 0x48;
codeSiteCode[ptr++] = 0xB8;
foreach (var b in originalCode.Skip((int)offset + 16).Take(8))
{
if (originalOffset < instr.Value.Size)
{
codeSiteCode[ptr++] = b;
}
else
{
codeSiteCode[ptr++] = patchSiteCode[patchOffset++];
}
originalOffset++;
}
// restore call site 3
// mov [rbx+16], rax
codeSiteCode[ptr++] = 0x48;
codeSiteCode[ptr++] = 0x89;
codeSiteCode[ptr++] = 0x43;
codeSiteCode[ptr++] = 0x10;
// prepare rbx to put new patch in place
// add rbx,instrSize
codeSiteCode[ptr++] = 0x48;
codeSiteCode[ptr++] = 0x83;
codeSiteCode[ptr++] = 0xC3;
codeSiteCode[ptr++] = (byte)(instr.Value.Size);
// return
lastReturn = ptr;
codeSiteCode[ptr++] = 0xC3;
var endOfRestore = ptr;
Console.WriteLine($"mul: {endOfRestore - startOfRestore}");
codeSiteCode[multiplyImmediate] = (byte)(endOfRestore - startOfRestore);
offset += instr.Value.Size;
}
ptr = lastReturn;
// we set rbx to bogus so that patch is not written for last instruction in set
// mov rbx, constant
codeSiteCode[ptr++] = 0x48;
codeSiteCode[ptr++] = 0xBB;
foreach (var b in BitConverter.GetBytes((ulong)bogusAddress))
{
codeSiteCode[ptr++] = b;
}
// return
codeSiteCode[ptr] = 0xC3;
DebugProcessUtils.WriteBytes(process, (ulong)codeAddress, codeSiteCode);
DebugProcessUtils.WriteBytes(process, patchSite, patchSiteCode);
}
