diff options
Diffstat (limited to '')
| -rw-r--r-- | mozglue/misc/nsWindowsDllInterceptor.h | 819 |
1 files changed, 819 insertions, 0 deletions
diff --git a/mozglue/misc/nsWindowsDllInterceptor.h b/mozglue/misc/nsWindowsDllInterceptor.h new file mode 100644 index 0000000000..d6afc9bb7f --- /dev/null +++ b/mozglue/misc/nsWindowsDllInterceptor.h @@ -0,0 +1,819 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* vim: set ts=8 sts=2 et sw=2 tw=80: */ +/* 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 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +#ifndef NS_WINDOWS_DLL_INTERCEPTOR_H_ +#define NS_WINDOWS_DLL_INTERCEPTOR_H_ + +#include <wchar.h> +#include <windows.h> +#include <winternl.h> + +#include <utility> + +#include "mozilla/ArrayUtils.h" +#include "mozilla/Assertions.h" +#include "mozilla/Atomics.h" +#include "mozilla/Attributes.h" +#include "mozilla/CheckedInt.h" +#include "mozilla/DebugOnly.h" +#include "mozilla/NativeNt.h" +#include "mozilla/Tuple.h" +#include "mozilla/Types.h" +#include "mozilla/UniquePtr.h" +#include "mozilla/Vector.h" +#include "mozilla/interceptor/MMPolicies.h" +#include "mozilla/interceptor/PatcherDetour.h" +#include "mozilla/interceptor/PatcherNopSpace.h" +#include "mozilla/interceptor/VMSharingPolicies.h" +#include "nsWindowsHelpers.h" + +/* + * Simple function interception. + * + * We have two separate mechanisms for intercepting a function: We can use the + * built-in nop space, if it exists, or we can create a detour. + * + * Using the built-in nop space works as follows: On x86-32, DLL functions + * begin with a two-byte nop (mov edi, edi) and are preceeded by five bytes of + * NOP instructions. + * + * When we detect a function with this prelude, we do the following: + * + * 1. Write a long jump to our interceptor function into the five bytes of NOPs + * before the function. + * + * 2. Write a short jump -5 into the two-byte nop at the beginning of the + * function. + * + * This mechanism is nice because it's thread-safe. It's even safe to do if + * another thread is currently running the function we're modifying! + * + * When the WindowsDllNopSpacePatcher is destroyed, we overwrite the short jump + * but not the long jump, so re-intercepting the same function won't work, + * because its prelude won't match. + * + * + * Unfortunately nop space patching doesn't work on functions which don't have + * this magic prelude (and in particular, x86-64 never has the prelude). So + * when we can't use the built-in nop space, we fall back to using a detour, + * which works as follows: + * + * 1. Save first N bytes of OrigFunction to trampoline, where N is a + * number of bytes >= 5 that are instruction aligned. + * + * 2. Replace first 5 bytes of OrigFunction with a jump to the Hook + * function. + * + * 3. After N bytes of the trampoline, add a jump to OrigFunction+N to + * continue original program flow. + * + * 4. Hook function needs to call the trampoline during its execution, + * to invoke the original function (so address of trampoline is + * returned). + * + * When the WindowsDllDetourPatcher object is destructed, OrigFunction is + * patched again to jump directly to the trampoline instead of going through + * the hook function. As such, re-intercepting the same function won't work, as + * jump instructions are not supported. + * + * Note that this is not thread-safe. Sad day. + * + */ + +#if defined(_M_IX86) && defined(__clang__) && __has_declspec_attribute(guard) +// On x86, nop-space patches return to the second instruction of their target. +// This is a deliberate violation of Control Flow Guard, so disable the check. +# define INTERCEPTOR_DISABLE_CFGUARD __declspec(guard(nocf)) +#else +# define INTERCEPTOR_DISABLE_CFGUARD /* nothing */ +#endif + +namespace mozilla { +namespace interceptor { + +template <typename T> +struct OriginalFunctionPtrTraits; + +template <typename R, typename... Args> +struct OriginalFunctionPtrTraits<R (*)(Args...)> { + using ReturnType = R; +}; + +#if defined(_M_IX86) +template <typename R, typename... Args> +struct OriginalFunctionPtrTraits<R(__stdcall*)(Args...)> { + using ReturnType = R; +}; + +template <typename R, typename... Args> +struct OriginalFunctionPtrTraits<R(__fastcall*)(Args...)> { + using ReturnType = R; +}; +#endif // defined(_M_IX86) + +template <typename InterceptorT, typename FuncPtrT> +class FuncHook final { + public: + using ThisType = FuncHook<InterceptorT, FuncPtrT>; + using ReturnType = typename OriginalFunctionPtrTraits<FuncPtrT>::ReturnType; + + constexpr FuncHook() : mOrigFunc(nullptr), mInitOnce(INIT_ONCE_STATIC_INIT) {} + + ~FuncHook() = default; + + bool Set(InterceptorT& aInterceptor, const char* aName, FuncPtrT aHookDest) { + LPVOID addHookOk = nullptr; + InitOnceContext ctx(this, &aInterceptor, aName, aHookDest, false); + + return ::InitOnceExecuteOnce(&mInitOnce, &InitOnceCallback, &ctx, + &addHookOk) && + addHookOk; + } + + bool SetDetour(InterceptorT& aInterceptor, const char* aName, + FuncPtrT aHookDest) { + LPVOID addHookOk = nullptr; + InitOnceContext ctx(this, &aInterceptor, aName, aHookDest, true); + + return ::InitOnceExecuteOnce(&mInitOnce, &InitOnceCallback, &ctx, + &addHookOk) && + addHookOk; + } + + explicit operator bool() const { return !!mOrigFunc; } + + template <typename... ArgsType> + INTERCEPTOR_DISABLE_CFGUARD ReturnType operator()(ArgsType&&... aArgs) const { + return mOrigFunc(std::forward<ArgsType>(aArgs)...); + } + + FuncPtrT GetStub() const { return mOrigFunc; } + + // One-time init stuff cannot be moved or copied + FuncHook(const FuncHook&) = delete; + FuncHook(FuncHook&&) = delete; + FuncHook& operator=(const FuncHook&) = delete; + FuncHook& operator=(FuncHook&& aOther) = delete; + + private: + struct MOZ_RAII InitOnceContext final { + InitOnceContext(ThisType* aHook, InterceptorT* aInterceptor, + const char* aName, FuncPtrT aHookDest, bool aForceDetour) + : mHook(aHook), + mInterceptor(aInterceptor), + mName(aName), + mHookDest(reinterpret_cast<void*>(aHookDest)), + mForceDetour(aForceDetour) {} + + ThisType* mHook; + InterceptorT* mInterceptor; + const char* mName; + void* mHookDest; + bool mForceDetour; + }; + + private: + bool Apply(InterceptorT* aInterceptor, const char* aName, void* aHookDest) { + return aInterceptor->AddHook(aName, reinterpret_cast<intptr_t>(aHookDest), + reinterpret_cast<void**>(&mOrigFunc)); + } + + bool ApplyDetour(InterceptorT* aInterceptor, const char* aName, + void* aHookDest) { + return aInterceptor->AddDetour(aName, reinterpret_cast<intptr_t>(aHookDest), + reinterpret_cast<void**>(&mOrigFunc)); + } + + static BOOL CALLBACK InitOnceCallback(PINIT_ONCE aInitOnce, PVOID aParam, + PVOID* aOutContext) { + MOZ_ASSERT(aOutContext); + + bool result; + auto ctx = reinterpret_cast<InitOnceContext*>(aParam); + if (ctx->mForceDetour) { + result = ctx->mHook->ApplyDetour(ctx->mInterceptor, ctx->mName, + ctx->mHookDest); + } else { + result = ctx->mHook->Apply(ctx->mInterceptor, ctx->mName, ctx->mHookDest); + } + + *aOutContext = + result ? reinterpret_cast<PVOID>(1U << INIT_ONCE_CTX_RESERVED_BITS) + : nullptr; + return TRUE; + } + + private: + FuncPtrT mOrigFunc; + INIT_ONCE mInitOnce; +}; + +template <typename InterceptorT, typename FuncPtrT> +class MOZ_ONLY_USED_TO_AVOID_STATIC_CONSTRUCTORS FuncHookCrossProcess final { + public: + using ThisType = FuncHookCrossProcess<InterceptorT, FuncPtrT>; + using ReturnType = typename OriginalFunctionPtrTraits<FuncPtrT>::ReturnType; + +#if defined(DEBUG) + FuncHookCrossProcess() {} +#endif // defined(DEBUG) + + bool Set(nt::CrossExecTransferManager& aTransferMgr, + InterceptorT& aInterceptor, const char* aName, FuncPtrT aHookDest) { + FuncPtrT origFunc; + if (!aInterceptor.AddHook(aName, reinterpret_cast<intptr_t>(aHookDest), + reinterpret_cast<void**>(&origFunc))) { + return false; + } + + return CopyStubToChildProcess(aTransferMgr, aInterceptor, origFunc); + } + + bool SetDetour(nt::CrossExecTransferManager& aTransferMgr, + InterceptorT& aInterceptor, const char* aName, + FuncPtrT aHookDest) { + FuncPtrT origFunc; + if (!aInterceptor.AddDetour(aName, reinterpret_cast<intptr_t>(aHookDest), + reinterpret_cast<void**>(&origFunc))) { + return false; + } + + return CopyStubToChildProcess(aTransferMgr, aInterceptor, origFunc); + } + + explicit operator bool() const { return !!mOrigFunc; } + + /** + * NB: This operator is only meaningful when invoked in the target process! + */ + template <typename... ArgsType> + ReturnType operator()(ArgsType&&... aArgs) const { + return mOrigFunc(std::forward<ArgsType>(aArgs)...); + } + +#if defined(DEBUG) + FuncHookCrossProcess(const FuncHookCrossProcess&) = delete; + FuncHookCrossProcess(FuncHookCrossProcess&&) = delete; + FuncHookCrossProcess& operator=(const FuncHookCrossProcess&) = delete; + FuncHookCrossProcess& operator=(FuncHookCrossProcess&& aOther) = delete; +#endif // defined(DEBUG) + + private: + bool CopyStubToChildProcess(nt::CrossExecTransferManager& aTransferMgr, + InterceptorT& aInterceptor, FuncPtrT aStub) { + LauncherVoidResult writeResult = + aTransferMgr.Transfer(&mOrigFunc, &aStub, sizeof(FuncPtrT)); + if (writeResult.isErr()) { +#ifdef MOZ_USE_LAUNCHER_ERROR + const mozilla::WindowsError& err = writeResult.inspectErr().mError; +#else + const mozilla::WindowsError& err = writeResult.inspectErr(); +#endif + aInterceptor.SetLastDetourError(FUNCHOOKCROSSPROCESS_COPYSTUB_ERROR, + err.AsHResult()); + return false; + } + return true; + } + + private: + FuncPtrT mOrigFunc; +}; + +template <typename MMPolicyT, typename InterceptorT> +struct TypeResolver; + +template <typename InterceptorT> +struct TypeResolver<mozilla::interceptor::MMPolicyInProcess, InterceptorT> { + template <typename FuncPtrT> + using FuncHookType = FuncHook<InterceptorT, FuncPtrT>; +}; + +template <typename InterceptorT> +struct TypeResolver<mozilla::interceptor::MMPolicyOutOfProcess, InterceptorT> { + template <typename FuncPtrT> + using FuncHookType = FuncHookCrossProcess<InterceptorT, FuncPtrT>; +}; + +template <typename VMPolicy = mozilla::interceptor::VMSharingPolicyShared> +class WindowsDllInterceptor final + : public TypeResolver<typename VMPolicy::MMPolicyT, + WindowsDllInterceptor<VMPolicy>> { + typedef WindowsDllInterceptor<VMPolicy> ThisType; + + interceptor::WindowsDllDetourPatcher<VMPolicy> mDetourPatcher; +#if defined(_M_IX86) + interceptor::WindowsDllNopSpacePatcher<typename VMPolicy::MMPolicyT> + mNopSpacePatcher; +#endif // defined(_M_IX86) + + HMODULE mModule; + + public: + template <typename... Args> + explicit WindowsDllInterceptor(Args&&... aArgs) + : mDetourPatcher(std::forward<Args>(aArgs)...) +#if defined(_M_IX86) + , + mNopSpacePatcher(std::forward<Args>(aArgs)...) +#endif // defined(_M_IX86) + , + mModule(nullptr) { + } + + WindowsDllInterceptor(const WindowsDllInterceptor&) = delete; + WindowsDllInterceptor(WindowsDllInterceptor&&) = delete; + WindowsDllInterceptor& operator=(const WindowsDllInterceptor&) = delete; + WindowsDllInterceptor& operator=(WindowsDllInterceptor&&) = delete; + + ~WindowsDllInterceptor() { Clear(); } + + template <size_t N> + void Init(const char (&aModuleName)[N]) { + wchar_t moduleName[N]; + + for (size_t i = 0; i < N; ++i) { + MOZ_ASSERT(!(aModuleName[i] & 0x80), + "Use wide-character overload for non-ASCII module names"); + moduleName[i] = aModuleName[i]; + } + + Init(moduleName); + } + + void Init(const wchar_t* aModuleName) { + if (mModule) { + return; + } + + mModule = ::LoadLibraryW(aModuleName); + } + + /** Force a specific configuration for testing purposes. NOT to be used in + production code! **/ + void TestOnlyDetourInit(const wchar_t* aModuleName, DetourFlags aFlags) { + Init(aModuleName); + mDetourPatcher.Init(aFlags); + } + + void Clear() { + if (!mModule) { + return; + } + +#if defined(_M_IX86) + mNopSpacePatcher.Clear(); +#endif // defined(_M_IX86) + mDetourPatcher.Clear(); + + // NB: We intentionally leak mModule + } + +#if defined(NIGHTLY_BUILD) + const Maybe<DetourError>& GetLastDetourError() const { + return mDetourPatcher.GetLastDetourError(); + } +#endif // defined(NIGHTLY_BUILD) + template <typename... Args> + void SetLastDetourError(Args&&... aArgs) { + return mDetourPatcher.SetLastDetourError(std::forward<Args>(aArgs)...); + } + + constexpr static uint32_t GetWorstCaseRequiredBytesToPatch() { + return WindowsDllDetourPatcherPrimitive< + typename VMPolicy::MMPolicyT>::GetWorstCaseRequiredBytesToPatch(); + } + + private: + /** + * Hook/detour the method aName from the DLL we set in Init so that it calls + * aHookDest instead. Returns the original method pointer in aOrigFunc + * and returns true if successful. + * + * IMPORTANT: If you use this method, please add your case to the + * TestDllInterceptor in order to detect future failures. Even if this + * succeeds now, updates to the hooked DLL could cause it to fail in + * the future. + */ + bool AddHook(const char* aName, intptr_t aHookDest, void** aOrigFunc) { + // Use a nop space patch if possible, otherwise fall back to a detour. + // This should be the preferred method for adding hooks. + if (!mModule) { + mDetourPatcher.SetLastDetourError(DetourResultCode::INTERCEPTOR_MOD_NULL); + return false; + } + + if (!mDetourPatcher.IsPageAccessible( + nt::PEHeaders::HModuleToBaseAddr<uintptr_t>(mModule))) { + mDetourPatcher.SetLastDetourError( + DetourResultCode::INTERCEPTOR_MOD_INACCESSIBLE); + return false; + } + + FARPROC proc = mDetourPatcher.GetProcAddress(mModule, aName); + if (!proc) { + mDetourPatcher.SetLastDetourError( + DetourResultCode::INTERCEPTOR_PROC_NULL); + return false; + } + + if (!mDetourPatcher.IsPageAccessible(reinterpret_cast<uintptr_t>(proc))) { + mDetourPatcher.SetLastDetourError( + DetourResultCode::INTERCEPTOR_PROC_INACCESSIBLE); + return false; + } + +#if defined(_M_IX86) + if (mNopSpacePatcher.AddHook(proc, aHookDest, aOrigFunc)) { + return true; + } +#endif // defined(_M_IX86) + + return AddDetour(proc, aHookDest, aOrigFunc); + } + + /** + * Detour the method aName from the DLL we set in Init so that it calls + * aHookDest instead. Returns the original method pointer in aOrigFunc + * and returns true if successful. + * + * IMPORTANT: If you use this method, please add your case to the + * TestDllInterceptor in order to detect future failures. Even if this + * succeeds now, updates to the detoured DLL could cause it to fail in + * the future. + */ + bool AddDetour(const char* aName, intptr_t aHookDest, void** aOrigFunc) { + // Generally, code should not call this method directly. Use AddHook unless + // there is a specific need to avoid nop space patches. + if (!mModule) { + mDetourPatcher.SetLastDetourError(DetourResultCode::INTERCEPTOR_MOD_NULL); + return false; + } + + if (!mDetourPatcher.IsPageAccessible( + nt::PEHeaders::HModuleToBaseAddr<uintptr_t>(mModule))) { + mDetourPatcher.SetLastDetourError( + DetourResultCode::INTERCEPTOR_MOD_INACCESSIBLE); + return false; + } + + FARPROC proc = mDetourPatcher.GetProcAddress(mModule, aName); + if (!proc) { + mDetourPatcher.SetLastDetourError( + DetourResultCode::INTERCEPTOR_PROC_NULL); + return false; + } + + if (!mDetourPatcher.IsPageAccessible(reinterpret_cast<uintptr_t>(proc))) { + mDetourPatcher.SetLastDetourError( + DetourResultCode::INTERCEPTOR_PROC_INACCESSIBLE); + return false; + } + + return AddDetour(proc, aHookDest, aOrigFunc); + } + + bool AddDetour(FARPROC aProc, intptr_t aHookDest, void** aOrigFunc) { + MOZ_ASSERT(mModule && aProc); + + if (!mDetourPatcher.Initialized()) { + DetourFlags flags = DetourFlags::eDefault; +#if defined(_M_X64) + // NTDLL hooks should attempt to use a 10-byte patch because some + // injected DLLs do the same and interfere with our stuff. + bool needs10BytePatch = (mModule == ::GetModuleHandleW(L"ntdll.dll")); + + bool isWin8Or81 = IsWin8OrLater() && (!IsWin10OrLater()); + bool isWin8 = IsWin8OrLater() && (!IsWin8Point1OrLater()); + + bool isKernel32Dll = (mModule == ::GetModuleHandleW(L"kernel32.dll")); + + bool isDuplicateHandle = (reinterpret_cast<void*>(aProc) == + reinterpret_cast<void*>(&::DuplicateHandle)); + + // CloseHandle on Windows 8/8.1 only accomodates 10-byte patches. + needs10BytePatch |= isWin8Or81 && isKernel32Dll && + (reinterpret_cast<void*>(aProc) == + reinterpret_cast<void*>(&CloseHandle)); + + // CreateFileA and DuplicateHandle on Windows 8 require 10-byte patches. + needs10BytePatch |= isWin8 && isKernel32Dll && + ((reinterpret_cast<void*>(aProc) == + reinterpret_cast<void*>(&::CreateFileA)) || + isDuplicateHandle); + + if (needs10BytePatch) { + flags |= DetourFlags::eEnable10BytePatch; + } + + if (isWin8 && isDuplicateHandle) { + // Because we can't detour Win8's KERNELBASE!DuplicateHandle, + // we detour kernel32!DuplicateHandle (See bug 1659398). + flags |= DetourFlags::eDontResolveRedirection; + } +#endif // defined(_M_X64) + + mDetourPatcher.Init(flags); + } + + return mDetourPatcher.AddHook(aProc, aHookDest, aOrigFunc); + } + + private: + template <typename InterceptorT, typename FuncPtrT> + friend class FuncHook; + + template <typename InterceptorT, typename FuncPtrT> + friend class FuncHookCrossProcess; +}; + +/** + * IAT patching is intended for use when we only want to intercept a function + * call originating from a specific module. + */ +class WindowsIATPatcher final { + public: + template <typename FuncPtrT> + using FuncHookType = FuncHook<WindowsIATPatcher, FuncPtrT>; + + private: + static bool CheckASCII(const char* aInStr) { + while (*aInStr) { + if (*aInStr & 0x80) { + return false; + } + ++aInStr; + } + return true; + } + + static bool AddHook(HMODULE aFromModule, const char* aToModuleName, + const char* aTargetFnName, void* aHookDest, + Atomic<void*>* aOutOrigFunc) { + if (!aFromModule || !aToModuleName || !aTargetFnName || !aOutOrigFunc) { + return false; + } + + // PE Spec requires ASCII names for imported module names + const bool isModuleNameAscii = CheckASCII(aToModuleName); + MOZ_ASSERT(isModuleNameAscii); + if (!isModuleNameAscii) { + return false; + } + + // PE Spec requires ASCII names for imported function names + const bool isTargetFnNameAscii = CheckASCII(aTargetFnName); + MOZ_ASSERT(isTargetFnNameAscii); + if (!isTargetFnNameAscii) { + return false; + } + + nt::PEHeaders headers(aFromModule); + if (!headers) { + return false; + } + + PIMAGE_IMPORT_DESCRIPTOR impDesc = + headers.GetImportDescriptor(aToModuleName); + if (!nt::PEHeaders::IsValid(impDesc)) { + // Either aFromModule does not import aToModuleName at load-time, or + // aToModuleName is a (currently unsupported) delay-load import. + return false; + } + + // Resolve the import name table (INT). + auto firstINTThunk = headers.template RVAToPtr<PIMAGE_THUNK_DATA>( + impDesc->OriginalFirstThunk); + if (!nt::PEHeaders::IsValid(firstINTThunk)) { + return false; + } + + Maybe<ptrdiff_t> thunkIndex; + + // Scan the INT for the location of the thunk for the function named + // 'aTargetFnName'. + for (PIMAGE_THUNK_DATA curINTThunk = firstINTThunk; + nt::PEHeaders::IsValid(curINTThunk); ++curINTThunk) { + if (IMAGE_SNAP_BY_ORDINAL(curINTThunk->u1.Ordinal)) { + // Currently not supporting import by ordinal; this isn't hard to add, + // but we won't bother unless necessary. + continue; + } + + PIMAGE_IMPORT_BY_NAME curThunkFnName = + headers.template RVAToPtr<PIMAGE_IMPORT_BY_NAME>( + curINTThunk->u1.AddressOfData); + MOZ_ASSERT(curThunkFnName); + if (!curThunkFnName) { + // Looks like we have a bad name descriptor. Try to continue. + continue; + } + + // Function name checks MUST be case-sensitive! + if (!strcmp(aTargetFnName, curThunkFnName->Name)) { + // We found the thunk. Save the index of this thunk, as the IAT thunk + // is located at the same index in that table as in the INT. + thunkIndex = Some(curINTThunk - firstINTThunk); + break; + } + } + + if (thunkIndex.isNothing()) { + // We never found a thunk for that function. Perhaps it's not imported? + return false; + } + + if (thunkIndex.value() < 0) { + // That's just wrong. + return false; + } + + auto firstIATThunk = + headers.template RVAToPtr<PIMAGE_THUNK_DATA>(impDesc->FirstThunk); + if (!nt::PEHeaders::IsValid(firstIATThunk)) { + return false; + } + + // Resolve the IAT thunk for the function we want + PIMAGE_THUNK_DATA targetThunk = &firstIATThunk[thunkIndex.value()]; + if (!nt::PEHeaders::IsValid(targetThunk)) { + return false; + } + + auto fnPtr = reinterpret_cast<Atomic<void*>*>(&targetThunk->u1.Function); + + // Now we can just change out its pointer with our hook function. + AutoVirtualProtect prot(fnPtr, sizeof(void*), PAGE_EXECUTE_READWRITE); + if (!prot) { + return false; + } + + // We do the exchange this way to ensure that *aOutOrigFunc is always valid + // once the atomic exchange has taken place. + void* tmp; + + do { + tmp = *fnPtr; + *aOutOrigFunc = tmp; + } while (!fnPtr->compareExchange(tmp, aHookDest)); + + return true; + } + + template <typename InterceptorT, typename FuncPtrT> + friend class FuncHook; +}; + +template <typename FuncPtrT> +class MOZ_ONLY_USED_TO_AVOID_STATIC_CONSTRUCTORS + FuncHook<WindowsIATPatcher, FuncPtrT> + final { + public: + using ThisType = FuncHook<WindowsIATPatcher, FuncPtrT>; + using ReturnType = typename OriginalFunctionPtrTraits<FuncPtrT>::ReturnType; + + constexpr FuncHook() + : mInitOnce(INIT_ONCE_STATIC_INIT), + mFromModule(nullptr), + mOrigFunc(nullptr) {} + +#if defined(DEBUG) + ~FuncHook() = default; +#endif // defined(DEBUG) + + bool Set(const wchar_t* aFromModuleName, const char* aToModuleName, + const char* aFnName, FuncPtrT aHookDest) { + nsModuleHandle fromModule(::LoadLibraryW(aFromModuleName)); + if (!fromModule) { + return false; + } + + return Set(fromModule, aToModuleName, aFnName, aHookDest); + } + + // We offer this overload in case the client wants finer-grained control over + // loading aFromModule. + bool Set(nsModuleHandle& aFromModule, const char* aToModuleName, + const char* aFnName, FuncPtrT aHookDest) { + LPVOID addHookOk = nullptr; + InitOnceContext ctx(this, aFromModule, aToModuleName, aFnName, aHookDest); + + bool result = ::InitOnceExecuteOnce(&mInitOnce, &InitOnceCallback, &ctx, + &addHookOk) && + addHookOk; + if (!result) { + return result; + } + + // If we successfully set the hook then we must retain a strong reference + // to the module that we modified. + mFromModule = aFromModule.disown(); + return result; + } + + explicit operator bool() const { return !!mOrigFunc; } + + template <typename... ArgsType> + ReturnType operator()(ArgsType&&... aArgs) const { + return mOrigFunc(std::forward<ArgsType>(aArgs)...); + } + + FuncPtrT GetStub() const { return mOrigFunc; } + +#if defined(DEBUG) + // One-time init stuff cannot be moved or copied + FuncHook(const FuncHook&) = delete; + FuncHook(FuncHook&&) = delete; + FuncHook& operator=(const FuncHook&) = delete; + FuncHook& operator=(FuncHook&& aOther) = delete; +#endif // defined(DEBUG) + + private: + struct MOZ_RAII InitOnceContext final { + InitOnceContext(ThisType* aHook, const nsModuleHandle& aFromModule, + const char* aToModuleName, const char* aFnName, + FuncPtrT aHookDest) + : mHook(aHook), + mFromModule(aFromModule), + mToModuleName(aToModuleName), + mFnName(aFnName), + mHookDest(reinterpret_cast<void*>(aHookDest)) {} + + ThisType* mHook; + const nsModuleHandle& mFromModule; + const char* mToModuleName; + const char* mFnName; + void* mHookDest; + }; + + private: + bool Apply(const nsModuleHandle& aFromModule, const char* aToModuleName, + const char* aFnName, void* aHookDest) { + return WindowsIATPatcher::AddHook( + aFromModule, aToModuleName, aFnName, aHookDest, + reinterpret_cast<Atomic<void*>*>(&mOrigFunc)); + } + + static BOOL CALLBACK InitOnceCallback(PINIT_ONCE aInitOnce, PVOID aParam, + PVOID* aOutContext) { + MOZ_ASSERT(aOutContext); + + auto ctx = reinterpret_cast<InitOnceContext*>(aParam); + bool result = ctx->mHook->Apply(ctx->mFromModule, ctx->mToModuleName, + ctx->mFnName, ctx->mHookDest); + + *aOutContext = + result ? reinterpret_cast<PVOID>(1U << INIT_ONCE_CTX_RESERVED_BITS) + : nullptr; + return TRUE; + } + + private: + INIT_ONCE mInitOnce; + HMODULE mFromModule; // never freed + FuncPtrT mOrigFunc; +}; + +/** + * This class applies an irreversible patch to jump to a target function + * without backing up the original function. + */ +class WindowsDllEntryPointInterceptor final { + using DllMainFn = BOOL(WINAPI*)(HINSTANCE, DWORD, LPVOID); + using MMPolicyT = MMPolicyInProcessEarlyStage; + + MMPolicyT mMMPolicy; + + public: + explicit WindowsDllEntryPointInterceptor( + const MMPolicyT::Kernel32Exports& aK32Exports) + : mMMPolicy(aK32Exports) {} + + bool Set(const nt::PEHeaders& aHeaders, DllMainFn aDestination) { + if (!aHeaders) { + return false; + } + + WindowsDllDetourPatcherPrimitive<MMPolicyT> patcher; + return patcher.AddIrreversibleHook( + mMMPolicy, aHeaders.GetEntryPoint(), + reinterpret_cast<uintptr_t>(aDestination)); + } +}; + +} // namespace interceptor + +using WindowsDllInterceptor = interceptor::WindowsDllInterceptor<>; + +using CrossProcessDllInterceptor = interceptor::WindowsDllInterceptor< + mozilla::interceptor::VMSharingPolicyUnique< + mozilla::interceptor::MMPolicyOutOfProcess>>; + +using WindowsIATPatcher = interceptor::WindowsIATPatcher; + +} // namespace mozilla + +#endif /* NS_WINDOWS_DLL_INTERCEPTOR_H_ */ |