126 lines
3.7 KiB
C++
126 lines
3.7 KiB
C++
// Copyright 2015-2023 The Mumble Developers. All rights reserved.
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// Use of this source code is governed by a BSD-style license
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// that can be found in the LICENSE file at the root of the
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// Mumble source tree or at <https://www.mumble.info/LICENSE>.
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#include "HardHook.h"
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#include "ods.h"
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#include <MinHook.h>
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static LONG minhook_init_once = 0;
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// EnsureMinHookInitialized ensures that the MinHook
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// library is initialized. If MinHook is already
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// initialized, calling this function is a no-op.
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static void EnsureMinHookInitialized() {
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// Ensure MH_Initialize is only called once.
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if (InterlockedCompareExchange(&minhook_init_once, 1, 0) == 0) {
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MH_STATUS status = MH_Initialize();
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if (status != MH_OK && status != MH_ERROR_ALREADY_INITIALIZED) {
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fods("HardHook: Failed to initialize minhook; MH_Initialize returned %s", MH_StatusToString(status));
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}
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}
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}
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/**
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* @brief Constructs a new hook without actually injecting.
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*/
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HardHook::HardHook() : m_func(nullptr), m_replacement(nullptr), call(nullptr) {
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EnsureMinHookInitialized();
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}
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/**
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* @brief Constructs a new hook by injecting given replacement function into func.
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* @see HardHook::setup
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* @param func Funktion to inject replacement into.
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* @param replacement Function to inject into func.
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*/
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HardHook::HardHook(voidFunc func, voidFunc replacement) : m_func(nullptr), m_replacement(nullptr), call(nullptr) {
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EnsureMinHookInitialized();
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setup(func, replacement);
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}
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/**
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* @brief Makes sure the given replacement function is run once func is called.
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*
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* Uses MinHook to put the hook in place.
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*
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* @param func Pointer to function to redirect.
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* @param replacement Pointer to code to redirect to.
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*/
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void HardHook::setup(voidFunc func, voidFunc replacement) {
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m_func = func;
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m_replacement = replacement;
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MH_STATUS status = MH_CreateHook((LPVOID) func, (LPVOID) replacement, (LPVOID *) &call);
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if (status != MH_OK) {
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fods("HardHook: setup failed, MH_CreateHook returned %s", MH_StatusToString(status));
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}
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inject(true);
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}
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void HardHook::setupInterface(IUnknown *unkn, LONG funcoffset, voidFunc replacement) {
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fods("HardHook: setupInterface: Replacing %p function #%ld", unkn, funcoffset);
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void **ptr = reinterpret_cast< void ** >(unkn);
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ptr = reinterpret_cast< void ** >(ptr[0]);
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setup(reinterpret_cast< voidFunc >(ptr[funcoffset]), replacement);
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}
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void HardHook::reset() {
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m_func = nullptr;
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m_replacement = nullptr;
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call = nullptr;
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}
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/**
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* @brief Injects redirection code into the target function.
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*
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* @param force No-op in the MinHook-based HardHook implementation.
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*/
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void HardHook::inject(bool force) {
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if (!force) {
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// MinHook guarantees the presence of a trampoline, so
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// inject() and restore() are no-ops unless force is
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// set to true.
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return;
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}
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MH_STATUS status = MH_EnableHook((LPVOID) m_func);
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if (status != MH_OK) {
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fods("HardHook: inject() failed: MH_EnableHook returned %s", MH_StatusToString(status));
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}
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}
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/**
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* @brief Restores the original code in a target function.
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*
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* @param force No-op in the MinHook-based HardHook implementation.
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*/
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void HardHook::restore(bool force) {
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if (!force) {
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// MinHook guarantees the presence of a trampoline, so
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// inject() and restore() are no-ops unless force is
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// set to true.
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return;
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}
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MH_STATUS status = MH_DisableHook((LPVOID) m_func);
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if (status != MH_OK) {
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fods("HardHook: restore() failed: MH_DisableHook returned %s", MH_StatusToString(status));
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}
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}
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void HardHook::print() {
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fods("HardHook: unused 'print' method called for MinHook-based HardHook");
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}
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/**
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* @brief No-op in MinHook-based HardHook implementation.
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*/
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void HardHook::check() {
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fods("HardHook: unused 'check' method called for MinHook-based HardHook");
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}
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