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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
/*
* Given a PID, this program attempts to inject a DLL into the process
* with that PID. The DLL it attempts to inject, "crashinjectdll.dll",
* must exist alongside this exe. The DLL will then crash the process.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <windows.h>
int main(int argc, char** argv) {
if (argc != 2) {
fprintf(stderr, "Usage: crashinject <PID>\n");
return 1;
}
int pid = atoi(argv[1]);
if (pid <= 0) {
fprintf(stderr, "Usage: crashinject <PID>\n");
return 1;
}
// find our DLL to inject
wchar_t filename[_MAX_PATH];
if (GetModuleFileNameW(nullptr, filename,
sizeof(filename) / sizeof(wchar_t)) == 0)
return 1;
wchar_t* slash = wcsrchr(filename, L'\\');
if (slash == nullptr) return 1;
slash++;
wcscpy(slash, L"crashinjectdll.dll");
// now find our target process
HANDLE targetProc =
OpenProcess(PROCESS_VM_OPERATION | PROCESS_VM_WRITE |
PROCESS_CREATE_THREAD | PROCESS_QUERY_INFORMATION,
FALSE, pid);
if (targetProc == nullptr) {
fprintf(stderr, "Error %lu opening target process\n", GetLastError());
return 1;
}
/*
* This is sort of insane, but we're implementing a technique described here:
*
* The gist is to use CreateRemoteThread to create a thread in the other
* process, but cheat and make the thread function kernel32!LoadLibrary,
* so that the only remote data we have to pass to the other process
* is the path to the library we want to load. The library we're loading
* will then do its dirty work inside the other process.
*/
HMODULE hKernel32 = GetModuleHandleW(L"Kernel32");
// allocate some memory to hold the path in the remote process
void* pLibRemote = VirtualAllocEx(targetProc, nullptr, sizeof(filename),
MEM_COMMIT, PAGE_READWRITE);
if (pLibRemote == nullptr) {
fprintf(stderr, "Error %lu in VirtualAllocEx\n", GetLastError());
CloseHandle(targetProc);
return 1;
}
if (!WriteProcessMemory(targetProc, pLibRemote, (void*)filename,
sizeof(filename), nullptr)) {
fprintf(stderr, "Error %lu in WriteProcessMemory\n", GetLastError());
VirtualFreeEx(targetProc, pLibRemote, sizeof(filename), MEM_RELEASE);
CloseHandle(targetProc);
return 1;
}
// Now create a thread in the target process that will load our DLL
HANDLE hThread = CreateRemoteThread(
targetProc, nullptr, 0,
(LPTHREAD_START_ROUTINE)GetProcAddress(hKernel32, "LoadLibraryW"),
pLibRemote, 0, nullptr);
if (hThread == nullptr) {
fprintf(stderr, "Error %lu in CreateRemoteThread\n", GetLastError());
VirtualFreeEx(targetProc, pLibRemote, sizeof(filename), MEM_RELEASE);
CloseHandle(targetProc);
return 1;
}
WaitForSingleObject(hThread, INFINITE);
// Cleanup, not that it's going to matter at this point
CloseHandle(hThread);
VirtualFreeEx(targetProc, pLibRemote, sizeof(filename), MEM_RELEASE);
CloseHandle(targetProc);
return 0;
}