Is injecting into self explicitly not allowed?

[lostmsu]

I am not getting any errors from DetourUpdateProcessWithDll, but my DLL is not getting loaded.

I tried using both the handle returned from GetCurrentProcess() and explicitly opening own PID using OpenProcess.

Even if it is not supported, I think it is a bug that DetourUpdateProcessWithDll completes successfully.

[sylveon]

DetourUpdateProcessWithDll is for internal use of DetourCreateProcessWithDll; it creates the process suspended, adds the DLL to the process's IAT using DetourUpdateProcessWithDll, then resumes the process, causing the loader to load that DLL. If you apply it to an already running process, then that won't work as the loader has already processed the IAT.

If you want to forcefully load a DLL into a process that has already been launched, try using CreateRemoteThread + LoadLibrary (or just LoadLibrary if it's in your own process).

[lostmsu]

Thanks for the explanation.

Sounds like if I want to expose DetourUpdateProcessWithDll my wrapper would need to check if the target process is in a suitable state.

Does Detours simplify CreateRemoteThread in any way?

[sylveon]

No, it doesn't simplify it but it's also very simple to use (error handling and resource management omitted):

std::wstring dllLocation = L"C:\\thing.dll";
HANDLE hProcess = OpenProcess(PROCESS_CREATE_THREAD | PROCESS_QUERY_INFORMATION | PROCESS_VM_OPERATION | PROCESS_VM_READ | PROCESS_VM_WRITE, false, pid);

const size_t size = (dllLocation.length() + 1) * sizeof(wchar_t);
void* remotePtr = VirtualAllocEx(hProcess, nullptr, size, MEM_COMMIT | MEM_RESERVE, PAGE_READWRITE);

WriteProcessMemory(hProcess, remotePtr, dllLocation.c_str(), size, nullptr);
CreateRemoteThread(hProcess, nullptr, 0, reinterpret_cast<LPTHREAD_START_ROUTINE>(LoadLibrary), remotePtr, 0, nullptr);