Simple injector that launches a process with a dll injected and returns the launched PID

injector.cpp

@@ -0,0 +1,112 @@
+#include "injector.h"
+
+#include <cassert>
+#include <windows.h>
+
+namespace {
+
+DWORD ExecuteFunctionInProcess(HANDLE process, void const* function, void const* argument, size_t argument_size)
+{
+    void* argument_buffer{nullptr};
+    if (argument != nullptr && argument_size > 0) {
+        argument_buffer = VirtualAllocEx(process, nullptr, argument_size, MEM_COMMIT | MEM_RESERVE, PAGE_READWRITE);
+        WriteProcessMemory(process, argument_buffer, argument, argument_size, nullptr);
+    }
+
+    auto thread = CreateRemoteThread(
+        process,
+        nullptr,
+        0,
+        (LPTHREAD_START_ROUTINE)function,
+        argument_buffer,
+        0,
+        nullptr);
+
+    DWORD result{0};
+    WaitForSingleObject(thread, INFINITE);
+    GetExitCodeThread(thread, &result);
+
+    if (argument_buffer != nullptr) {
+        VirtualFreeEx(process, argument_buffer, 0, MEM_RELEASE);
+        argument_buffer = nullptr;
+    }
+
+    return result;
+}
+
+}
+
+uint32_t LaunchInjected(
+    wchar_t const* command_line, 
+    wchar_t const* working_directory, 
+    wchar_t const* injected_dll, 
+    char const* initialize_function)
+{
+    if (!command_line || !working_directory || !injected_dll || !initialize_function) {
+        return 0;
+    }
+
+    PROCESS_INFORMATION process_info{};
+    STARTUPINFO startup_info{};
+    startup_info.cb = sizeof(startup_info);
+
+    // or, you know, i could just const_cast and :pray:...
+    auto command_length = wcslen(command_line);
+    wchar_t* mutable_command_line = new wchar_t[command_length + 1];
+    wcsncpy(mutable_command_line, command_line, command_length);
+    mutable_command_line[command_length] = L'\0';
+
+    auto process_launched = CreateProcess(
+        nullptr, 
+        mutable_command_line, 
+        nullptr, 
+        nullptr, 
+        false, 
+        CREATE_SUSPENDED, 
+        nullptr, 
+        working_directory, 
+        &startup_info, 
+        &process_info);
+    if (!process_launched) {
+        return 0;
+    }
+
+    delete mutable_command_line;
+    mutable_command_line = nullptr;
+
+    // technically wrong, but oh-so-useful. the base address of kernel32.dll is
+    // identical for all processes in any given session.
+    void* load_library = GetProcAddress(GetModuleHandle(L"kernel32.dll"), "LoadLibraryW");
+    assert(load_library);
+
+    void* remote_base_address = (void*)ExecuteFunctionInProcess(
+        process_info.hProcess, 
+        load_library, 
+        injected_dll, 
+        sizeof(wchar_t) * wcslen(injected_dll)
+    );
+    if (!remote_base_address) {
+        TerminateProcess(process_info.hProcess, 0);
+        return 0;
+    }
+
+    void* local_base_address = (void*)LoadLibrary(injected_dll);
+    ptrdiff_t offset =
+        (uintptr_t)GetProcAddress((HMODULE)local_base_address, initialize_function) - (uintptr_t)local_base_address;
+    FreeLibrary((HMODULE)local_base_address);
+
+    void* initialize_address = (void*)((uintptr_t)remote_base_address + offset);
+    ExecuteFunctionInProcess(process_info.hProcess, initialize_address, nullptr, 0);
+
+    ResumeThread(process_info.hThread);
+
+    CloseHandle(process_info.hThread);
+    CloseHandle(process_info.hProcess);
+
+    return static_cast<uint32_t>(process_info.dwProcessId);
+}
+
+int WINAPI DllMain(HMODULE, DWORD, LPVOID)
+{
+    return true;
+}

injector.h

@@ -0,0 +1,30 @@
+#ifndef INJECTOR_H_
+#define INJECTOR_H_
+
+#include <cstdint>
+
+#if defined(INJECTOR_EXPORTS)
+#define INJECTOR_EXPORT __declspec(dllexport)
+#else
+#define INJECTOR_EXPORT __declspec(dllimport)
+#endif
+
+#if defined(__cplusplus)
+extern "C" {
+#endif
+
+// Launches `command_line` from `working_directory` and injects `injected_dll`,
+// optionally calling `initialize_function` in after injection. If everything 
+// goes off without a hitch the process ID will be returned, otherwise 0.
+INJECTOR_EXPORT uint32_t LaunchInjected(
+    wchar_t const* command_line, 
+    wchar_t const* working_directory, 
+    wchar_t const* injected_dll, 
+    char const* initialize_function
+);
+
+#if defined(__cplusplus)
+}
+#endif
+
+#endif // INJECTOR_H_

injector.sln

@@ -0,0 +1,32 @@
+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio 14
+VisualStudioVersion = 14.0.25420.1
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "injector", "injector.vcxproj", "{28694F69-B04C-43AF-9DD1-812085A8E25A}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Debug|x64 = Debug|x64
+		Debug|x86 = Debug|x86
+		Release|Any CPU = Release|Any CPU
+		Release|x64 = Release|x64
+		Release|x86 = Release|x86
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{28694F69-B04C-43AF-9DD1-812085A8E25A}.Debug|Any CPU.ActiveCfg = Debug|Win32
+		{28694F69-B04C-43AF-9DD1-812085A8E25A}.Debug|x64.ActiveCfg = Debug|x64
+		{28694F69-B04C-43AF-9DD1-812085A8E25A}.Debug|x64.Build.0 = Debug|x64
+		{28694F69-B04C-43AF-9DD1-812085A8E25A}.Debug|x86.ActiveCfg = Debug|Win32
+		{28694F69-B04C-43AF-9DD1-812085A8E25A}.Debug|x86.Build.0 = Debug|Win32
+		{28694F69-B04C-43AF-9DD1-812085A8E25A}.Release|Any CPU.ActiveCfg = Release|Win32
+		{28694F69-B04C-43AF-9DD1-812085A8E25A}.Release|x64.ActiveCfg = Release|x64
+		{28694F69-B04C-43AF-9DD1-812085A8E25A}.Release|x64.Build.0 = Release|x64
+		{28694F69-B04C-43AF-9DD1-812085A8E25A}.Release|x86.ActiveCfg = Release|Win32
+		{28694F69-B04C-43AF-9DD1-812085A8E25A}.Release|x86.Build.0 = Release|Win32
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+EndGlobal

injector.vcxproj

@@ -0,0 +1,157 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project DefaultTargets="Build" ToolsVersion="14.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <ItemGroup Label="ProjectConfigurations">
+    <ProjectConfiguration Include="Debug|Win32">
+      <Configuration>Debug</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release|Win32">
+      <Configuration>Release</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Debug|x64">
+      <Configuration>Debug</Configuration>
+      <Platform>x64</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release|x64">
+      <Configuration>Release</Configuration>
+      <Platform>x64</Platform>
+    </ProjectConfiguration>
+  </ItemGroup>
+  <PropertyGroup Label="Globals">
+    <ProjectGuid>{28694F69-B04C-43AF-9DD1-812085A8E25A}</ProjectGuid>
+    <Keyword>Win32Proj</Keyword>
+    <RootNamespace>injector</RootNamespace>
+    <WindowsTargetPlatformVersion>8.1</WindowsTargetPlatformVersion>
+  </PropertyGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.Default.props" />
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'" Label="Configuration">
+    <ConfigurationType>DynamicLibrary</ConfigurationType>
+    <UseDebugLibraries>true</UseDebugLibraries>
+    <PlatformToolset>v140</PlatformToolset>
+    <CharacterSet>Unicode</CharacterSet>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
+    <ConfigurationType>DynamicLibrary</ConfigurationType>
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+    <PlatformToolset>v140</PlatformToolset>
+    <WholeProgramOptimization>true</WholeProgramOptimization>
+    <CharacterSet>Unicode</CharacterSet>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'" Label="Configuration">
+    <ConfigurationType>DynamicLibrary</ConfigurationType>
+    <UseDebugLibraries>true</UseDebugLibraries>
+    <PlatformToolset>v140</PlatformToolset>
+    <CharacterSet>Unicode</CharacterSet>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'" Label="Configuration">
+    <ConfigurationType>DynamicLibrary</ConfigurationType>
+    <UseDebugLibraries>false</UseDebugLibraries>
+    <PlatformToolset>v140</PlatformToolset>
+    <WholeProgramOptimization>true</WholeProgramOptimization>
+    <CharacterSet>Unicode</CharacterSet>
+  </PropertyGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
+  <ImportGroup Label="ExtensionSettings">
+  </ImportGroup>
+  <ImportGroup Label="Shared">
+  </ImportGroup>
+  <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
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+  <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Release|x64'">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+  </ImportGroup>
+  <PropertyGroup Label="UserMacros" />
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
+    <LinkIncremental>true</LinkIncremental>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">
+    <LinkIncremental>true</LinkIncremental>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
+    <LinkIncremental>false</LinkIncremental>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'">
+    <LinkIncremental>false</LinkIncremental>
+  </PropertyGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
+    <ClCompile>
+      <PrecompiledHeader>
+      </PrecompiledHeader>
+      <WarningLevel>Level3</WarningLevel>
+      <Optimization>Disabled</Optimization>
+      <PreprocessorDefinitions>WIN32;_CRT_SECURE_NO_WARNINGS;_DEBUG;_WINDOWS;_USRDLL;INJECTOR_EXPORTS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <RuntimeLibrary>MultiThreadedDebug</RuntimeLibrary>
+    </ClCompile>
+    <Link>
+      <SubSystem>Windows</SubSystem>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+    </Link>
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+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">
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+      <WarningLevel>Level3</WarningLevel>
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+    <Link>
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+      <GenerateDebugInformation>true</GenerateDebugInformation>
+    </Link>
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+    <ClCompile>
+      <WarningLevel>Level3</WarningLevel>
+      <PrecompiledHeader>
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+      <Optimization>MaxSpeed</Optimization>
+      <FunctionLevelLinking>true</FunctionLevelLinking>
+      <IntrinsicFunctions>true</IntrinsicFunctions>
+      <PreprocessorDefinitions>WIN32;_CRT_SECURE_NO_WARNINGS;NDEBUG;_WINDOWS;_USRDLL;INJECTOR_EXPORTS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <RuntimeLibrary>MultiThreaded</RuntimeLibrary>
+    </ClCompile>
+    <Link>
+      <SubSystem>Windows</SubSystem>
+      <EnableCOMDATFolding>true</EnableCOMDATFolding>
+      <OptimizeReferences>true</OptimizeReferences>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
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+  </ItemDefinitionGroup>
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+      <FunctionLevelLinking>true</FunctionLevelLinking>
+      <IntrinsicFunctions>true</IntrinsicFunctions>
+      <PreprocessorDefinitions>NDEBUG;_WINDOWS;_USRDLL;INJECTOR_EXPORTS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <RuntimeLibrary>MultiThreaded</RuntimeLibrary>
+    </ClCompile>
+    <Link>
+      <SubSystem>Windows</SubSystem>
+      <EnableCOMDATFolding>true</EnableCOMDATFolding>
+      <OptimizeReferences>true</OptimizeReferences>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+    </Link>
+  </ItemDefinitionGroup>
+  <ItemGroup>
+    <ClCompile Include="injector.cpp" />
+  </ItemGroup>
+  <ItemGroup>
+    <ClInclude Include="injector.h" />
+  </ItemGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
+  <ImportGroup Label="ExtensionTargets">
+  </ImportGroup>
+</Project>

injector.vcxproj.filters

@@ -0,0 +1,27 @@
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