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Diffstat (limited to 'toolkit/xre/dllservices/mozglue/interceptor/MMPolicies.h')
| -rw-r--r-- | toolkit/xre/dllservices/mozglue/interceptor/MMPolicies.h | 1031 |
1 files changed, 1031 insertions, 0 deletions
diff --git a/toolkit/xre/dllservices/mozglue/interceptor/MMPolicies.h b/toolkit/xre/dllservices/mozglue/interceptor/MMPolicies.h new file mode 100644 index 0000000000..0a309a1065 --- /dev/null +++ b/toolkit/xre/dllservices/mozglue/interceptor/MMPolicies.h @@ -0,0 +1,1031 @@ +/* -*- 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 https://mozilla.org/MPL/2.0/. */ + +#ifndef mozilla_interceptor_MMPolicies_h +#define mozilla_interceptor_MMPolicies_h + +#include "mozilla/Assertions.h" +#include "mozilla/CheckedInt.h" +#include "mozilla/DynamicallyLinkedFunctionPtr.h" +#include "mozilla/MathAlgorithms.h" +#include "mozilla/Maybe.h" +#include "mozilla/Span.h" +#include "mozilla/TypedEnumBits.h" +#include "mozilla/Types.h" +#include "mozilla/WindowsMapRemoteView.h" +#include "mozilla/WindowsUnwindInfo.h" + +#include <windows.h> + +#if (NTDDI_VERSION < NTDDI_WIN10_RS4) || defined(__MINGW32__) +PVOID WINAPI VirtualAlloc2(HANDLE Process, PVOID BaseAddress, SIZE_T Size, + ULONG AllocationType, ULONG PageProtection, + MEM_EXTENDED_PARAMETER* ExtendedParameters, + ULONG ParameterCount); +PVOID WINAPI MapViewOfFile3(HANDLE FileMapping, HANDLE Process, + PVOID BaseAddress, ULONG64 Offset, SIZE_T ViewSize, + ULONG AllocationType, ULONG PageProtection, + MEM_EXTENDED_PARAMETER* ExtendedParameters, + ULONG ParameterCount); +#endif // (NTDDI_VERSION < NTDDI_WIN10_RS4) || defined(__MINGW32__) + +// _CRT_RAND_S is not defined everywhere, but we need it. +#if !defined(_CRT_RAND_S) +extern "C" errno_t rand_s(unsigned int* randomValue); +#endif // !defined(_CRT_RAND_S) + +// Declaring only the functions we need in NativeNt.h. To include the entire +// NativeNt.h causes circular dependency. +namespace mozilla { +namespace nt { +SIZE_T WINAPI VirtualQueryEx(HANDLE aProcess, LPCVOID aAddress, + PMEMORY_BASIC_INFORMATION aMemInfo, + SIZE_T aMemInfoLen); + +SIZE_T WINAPI VirtualQuery(LPCVOID aAddress, PMEMORY_BASIC_INFORMATION aMemInfo, + SIZE_T aMemInfoLen); +} // namespace nt +} // namespace mozilla + +namespace mozilla { +namespace interceptor { + +// This class implements memory operations not involving any kernel32's +// functions, so that derived classes can use them. +class MOZ_TRIVIAL_CTOR_DTOR MMPolicyInProcessPrimitive { + protected: + bool ProtectInternal(decltype(&::VirtualProtect) aVirtualProtect, + void* aVAddress, size_t aSize, uint32_t aProtFlags, + uint32_t* aPrevProtFlags) const { + MOZ_ASSERT(aPrevProtFlags); + BOOL ok = aVirtualProtect(aVAddress, aSize, aProtFlags, + reinterpret_cast<PDWORD>(aPrevProtFlags)); + if (!ok && aPrevProtFlags) { + // VirtualProtect can fail but still set valid protection flags. + // Let's clear those upon failure. + *aPrevProtFlags = 0; + } + + return !!ok; + } + + public: + bool Read(void* aToPtr, const void* aFromPtr, size_t aLen) const { + ::memcpy(aToPtr, aFromPtr, aLen); + return true; + } + + bool Write(void* aToPtr, const void* aFromPtr, size_t aLen) const { + ::memcpy(aToPtr, aFromPtr, aLen); + return true; + } + + /** + * @return true if the page that hosts aVAddress is accessible. + */ + bool IsPageAccessible(uintptr_t aVAddress) const { + MEMORY_BASIC_INFORMATION mbi; + SIZE_T result = nt::VirtualQuery(reinterpret_cast<LPCVOID>(aVAddress), &mbi, + sizeof(mbi)); + + return result && mbi.AllocationProtect && mbi.State == MEM_COMMIT && + mbi.Protect != PAGE_NOACCESS; + } +}; + +class MOZ_TRIVIAL_CTOR_DTOR MMPolicyBase { + protected: + static uintptr_t AlignDown(const uintptr_t aUnaligned, + const uintptr_t aAlignTo) { + MOZ_ASSERT(IsPowerOfTwo(aAlignTo)); +#pragma warning(suppress : 4146) + return aUnaligned & (-aAlignTo); + } + + static uintptr_t AlignUp(const uintptr_t aUnaligned, + const uintptr_t aAlignTo) { + MOZ_ASSERT(IsPowerOfTwo(aAlignTo)); +#pragma warning(suppress : 4146) + return aUnaligned + ((-aUnaligned) & (aAlignTo - 1)); + } + + static PVOID AlignUpToRegion(PVOID aUnaligned, uintptr_t aAlignTo, + size_t aLen, size_t aDesiredLen) { + uintptr_t unaligned = reinterpret_cast<uintptr_t>(aUnaligned); + uintptr_t aligned = AlignUp(unaligned, aAlignTo); + MOZ_ASSERT(aligned >= unaligned); + + if (aLen < aligned - unaligned) { + return nullptr; + } + + aLen -= (aligned - unaligned); + return reinterpret_cast<PVOID>((aLen >= aDesiredLen) ? aligned : 0); + } + + public: +#if defined(NIGHTLY_BUILD) + Maybe<DetourError> mLastError; + const Maybe<DetourError>& GetLastDetourError() const { return mLastError; } + template <typename... Args> + void SetLastDetourError(Args&&... aArgs) { + mLastError = Some(DetourError(std::forward<Args>(aArgs)...)); + } +#else + template <typename... Args> + void SetLastDetourError(Args&&... aArgs) {} +#endif // defined(NIGHTLY_BUILD) + + DWORD ComputeAllocationSize(const uint32_t aRequestedSize) const { + MOZ_ASSERT(aRequestedSize); + DWORD result = aRequestedSize; + + const uint32_t granularity = GetAllocGranularity(); + + uint32_t mod = aRequestedSize % granularity; + if (mod) { + result += (granularity - mod); + } + + return result; + } + + DWORD GetAllocGranularity() const { + static const DWORD kAllocGranularity = []() -> DWORD { + SYSTEM_INFO sysInfo; + ::GetSystemInfo(&sysInfo); + return sysInfo.dwAllocationGranularity; + }(); + + return kAllocGranularity; + } + + DWORD GetPageSize() const { + static const DWORD kPageSize = []() -> DWORD { + SYSTEM_INFO sysInfo; + ::GetSystemInfo(&sysInfo); + return sysInfo.dwPageSize; + }(); + + return kPageSize; + } + + uintptr_t GetMaxUserModeAddress() const { + static const uintptr_t kMaxUserModeAddr = []() -> uintptr_t { + SYSTEM_INFO sysInfo; + ::GetSystemInfo(&sysInfo); + return reinterpret_cast<uintptr_t>(sysInfo.lpMaximumApplicationAddress); + }(); + + return kMaxUserModeAddr; + } + + static const uint8_t* GetLowerBound(const Span<const uint8_t>& aBounds) { + return &(*aBounds.cbegin()); + } + + static const uint8_t* GetUpperBoundIncl(const Span<const uint8_t>& aBounds) { + // We return an upper bound that is inclusive. + return &(*(aBounds.cend() - 1)); + } + + static const uint8_t* GetUpperBoundExcl(const Span<const uint8_t>& aBounds) { + // We return an upper bound that is exclusive by adding 1 to the inclusive + // upper bound. + return GetUpperBoundIncl(aBounds) + 1; + } + + /** + * It is convenient for us to provide address range information based on a + * "pivot" and a distance from that pivot, as branch instructions operate + * within a range of the program counter. OTOH, to actually manage the + * regions of memory, it is easier to think about them in terms of their + * lower and upper bounds. This function converts from the former format to + * the latter format. + */ + Maybe<Span<const uint8_t>> SpanFromPivotAndDistance( + const uint32_t aSize, const uintptr_t aPivotAddr, + const uint32_t aMaxDistanceFromPivot) const { + if (!aPivotAddr || !aMaxDistanceFromPivot) { + return Nothing(); + } + + // We don't allow regions below 1MB so that we're not allocating near any + // sensitive areas in our address space. + const uintptr_t kMinAllowableAddress = 0x100000; + + const uintptr_t kGranularity(GetAllocGranularity()); + + // We subtract the max distance from the pivot to determine our lower bound. + CheckedInt<uintptr_t> lowerBound(aPivotAddr); + lowerBound -= aMaxDistanceFromPivot; + if (lowerBound.isValid()) { + // In this case, the subtraction has not underflowed, but we still want + // the lower bound to be at least kMinAllowableAddress. + lowerBound = std::max(lowerBound.value(), kMinAllowableAddress); + } else { + // In this case, we underflowed. Forcibly set the lower bound to + // kMinAllowableAddress. + lowerBound = CheckedInt<uintptr_t>(kMinAllowableAddress); + } + + // Align up to the next unit of allocation granularity when necessary. + lowerBound = AlignUp(lowerBound.value(), kGranularity); + MOZ_ASSERT(lowerBound.isValid()); + if (!lowerBound.isValid()) { + return Nothing(); + } + + // We must ensure that our region is below the maximum allowable user-mode + // address, or our reservation will fail. + const uintptr_t kMaxUserModeAddr = GetMaxUserModeAddress(); + + // We add the max distance from the pivot to determine our upper bound. + CheckedInt<uintptr_t> upperBound(aPivotAddr); + upperBound += aMaxDistanceFromPivot; + if (upperBound.isValid()) { + // In this case, the addition has not overflowed, but we still want + // the upper bound to be at most kMaxUserModeAddr. + upperBound = std::min(upperBound.value(), kMaxUserModeAddr); + } else { + // In this case, we overflowed. Forcibly set the upper bound to + // kMaxUserModeAddr. + upperBound = CheckedInt<uintptr_t>(kMaxUserModeAddr); + } + + // Subtract the desired allocation size so that any chunk allocated in the + // region will be reachable. + upperBound -= aSize; + if (!upperBound.isValid()) { + return Nothing(); + } + + // Align down to the next unit of allocation granularity when necessary. + upperBound = AlignDown(upperBound.value(), kGranularity); + if (!upperBound.isValid()) { + return Nothing(); + } + + MOZ_ASSERT(lowerBound.value() < upperBound.value()); + if (lowerBound.value() >= upperBound.value()) { + return Nothing(); + } + + // Return the result as a Span + return Some(Span(reinterpret_cast<const uint8_t*>(lowerBound.value()), + upperBound.value() - lowerBound.value())); + } + + /** + * This function locates a virtual memory region of |aDesiredBytesLen| that + * resides in the interval [aRangeMin, aRangeMax). We do this by scanning the + * virtual memory space for a block of unallocated memory that is sufficiently + * large. + */ + PVOID FindRegion(HANDLE aProcess, const size_t aDesiredBytesLen, + const uint8_t* aRangeMin, const uint8_t* aRangeMax) { + // Convert the given pointers to uintptr_t because we should not + // compare two pointers unless they are from the same array or object. + uintptr_t rangeMin = reinterpret_cast<uintptr_t>(aRangeMin); + uintptr_t rangeMax = reinterpret_cast<uintptr_t>(aRangeMax); + + const DWORD kGranularity = GetAllocGranularity(); + if (!aDesiredBytesLen) { + SetLastDetourError(MMPOLICY_RESERVE_FINDREGION_INVALIDLEN); + return nullptr; + } + + MOZ_ASSERT(rangeMin < rangeMax); + if (rangeMin >= rangeMax) { + SetLastDetourError(MMPOLICY_RESERVE_FINDREGION_INVALIDRANGE); + return nullptr; + } + + // Generate a randomized base address that falls within the interval + // [aRangeMin, aRangeMax - aDesiredBytesLen] + unsigned int rnd = 0; + rand_s(&rnd); + + // Reduce rnd to a value that falls within the acceptable range + uintptr_t maxOffset = + (rangeMax - rangeMin - aDesiredBytesLen) / kGranularity; + // Divide by maxOffset + 1 because maxOffset * kGranularity is acceptable. + uintptr_t offset = (uintptr_t(rnd) % (maxOffset + 1)) * kGranularity; + + // Start searching at this address + const uintptr_t searchStart = rangeMin + offset; + // The max address needs to incorporate the desired length + const uintptr_t kMaxPtr = rangeMax - aDesiredBytesLen; + + MOZ_DIAGNOSTIC_ASSERT(searchStart <= kMaxPtr); + + MEMORY_BASIC_INFORMATION mbi; + SIZE_T len = sizeof(mbi); + + // Scan the range for a free chunk that is at least as large as + // aDesiredBytesLen + // Scan [searchStart, kMaxPtr] + for (uintptr_t address = searchStart; address <= kMaxPtr;) { + if (nt::VirtualQueryEx(aProcess, reinterpret_cast<uint8_t*>(address), + &mbi, len) != len) { + SetLastDetourError(MMPOLICY_RESERVE_FINDREGION_VIRTUALQUERY_ERROR, + ::GetLastError()); + return nullptr; + } + + if (mbi.State == MEM_FREE) { + // |mbi.BaseAddress| is aligned with the page granularity, but may not + // be aligned with the allocation granularity. VirtualAlloc does not + // accept such a non-aligned address unless the corresponding allocation + // region is free. So we get the next boundary's start address. + PVOID regionStart = AlignUpToRegion(mbi.BaseAddress, kGranularity, + mbi.RegionSize, aDesiredBytesLen); + if (regionStart) { + return regionStart; + } + } + + address = reinterpret_cast<uintptr_t>(mbi.BaseAddress) + mbi.RegionSize; + } + + // Scan [aRangeMin, searchStart) + for (uintptr_t address = rangeMin; address < searchStart;) { + if (nt::VirtualQueryEx(aProcess, reinterpret_cast<uint8_t*>(address), + &mbi, len) != len) { + SetLastDetourError(MMPOLICY_RESERVE_FINDREGION_VIRTUALQUERY_ERROR, + ::GetLastError()); + return nullptr; + } + + if (mbi.State == MEM_FREE) { + PVOID regionStart = AlignUpToRegion(mbi.BaseAddress, kGranularity, + mbi.RegionSize, aDesiredBytesLen); + if (regionStart) { + return regionStart; + } + } + + address = reinterpret_cast<uintptr_t>(mbi.BaseAddress) + mbi.RegionSize; + } + + SetLastDetourError(MMPOLICY_RESERVE_FINDREGION_NO_FREE_REGION, + ::GetLastError()); + return nullptr; + } + + /** + * This function reserves a |aSize| block of virtual memory. + * + * When |aBounds| is Nothing, it just calls |aReserveFn| and lets Windows + * choose the base address. + * + * Otherwise, it tries to call |aReserveRangeFn| to reserve the memory within + * the bounds provided by |aBounds|. It is advantageous to use this function + * because the OS's VM manager has better information as to which base + * addresses are the best to use. + * + * If |aReserveRangeFn| retuns Nothing, this means that the platform support + * is not available. In that case, we fall back to manually computing a region + * to use for reserving the memory by calling |FindRegion|. + */ + template <typename ReserveFnT, typename ReserveRangeFnT> + PVOID Reserve(HANDLE aProcess, const uint32_t aSize, + const ReserveFnT& aReserveFn, + const ReserveRangeFnT& aReserveRangeFn, + const Maybe<Span<const uint8_t>>& aBounds) { + if (!aBounds) { + // No restrictions, let the OS choose the base address + PVOID ret = aReserveFn(aProcess, nullptr, aSize); + if (!ret) { + SetLastDetourError(MMPOLICY_RESERVE_NOBOUND_RESERVE_ERROR, + ::GetLastError()); + } + return ret; + } + + const uint8_t* lowerBound = GetLowerBound(aBounds.ref()); + const uint8_t* upperBoundExcl = GetUpperBoundExcl(aBounds.ref()); + + Maybe<PVOID> result = + aReserveRangeFn(aProcess, aSize, lowerBound, upperBoundExcl); + if (result) { + return result.value(); + } + + // aReserveRangeFn is not available on this machine. We'll do a manual + // search. + + size_t curAttempt = 0; + const size_t kMaxAttempts = 8; + + // We loop here because |FindRegion| may return a base address that + // is reserved elsewhere before we have had a chance to reserve it + // ourselves. + while (curAttempt < kMaxAttempts) { + PVOID base = FindRegion(aProcess, aSize, lowerBound, upperBoundExcl); + if (!base) { + return nullptr; + } + + result = Some(aReserveFn(aProcess, base, aSize)); + if (result.value()) { + return result.value(); + } + + ++curAttempt; + } + + // If we run out of attempts, we fall through to the default case where + // the system chooses any base address it wants. In that case, the hook + // will be set on a best-effort basis. + PVOID ret = aReserveFn(aProcess, nullptr, aSize); + if (!ret) { + SetLastDetourError(MMPOLICY_RESERVE_FINAL_RESERVE_ERROR, + ::GetLastError()); + } + return ret; + } +}; + +class MOZ_TRIVIAL_CTOR_DTOR MMPolicyInProcess + : public MMPolicyInProcessPrimitive, + public MMPolicyBase { + public: + typedef MMPolicyInProcess MMPolicyT; + + constexpr MMPolicyInProcess() + : mBase(nullptr), mReservationSize(0), mCommitOffset(0) {} + + MMPolicyInProcess(const MMPolicyInProcess&) = delete; + MMPolicyInProcess& operator=(const MMPolicyInProcess&) = delete; + + MMPolicyInProcess(MMPolicyInProcess&& aOther) + : mBase(nullptr), mReservationSize(0), mCommitOffset(0) { + *this = std::move(aOther); + } + + MMPolicyInProcess& operator=(MMPolicyInProcess&& aOther) { + mBase = aOther.mBase; + aOther.mBase = nullptr; + + mCommitOffset = aOther.mCommitOffset; + aOther.mCommitOffset = 0; + + mReservationSize = aOther.mReservationSize; + aOther.mReservationSize = 0; + + return *this; + } + + explicit operator bool() const { return !!mBase; } + + /** + * Should we unhook everything upon destruction? + */ + bool ShouldUnhookUponDestruction() const { return true; } + +#if defined(_M_IX86) + bool WriteAtomic(void* aDestPtr, const uint16_t aValue) const { + *static_cast<uint16_t*>(aDestPtr) = aValue; + return true; + } +#endif // defined(_M_IX86) + + bool Protect(void* aVAddress, size_t aSize, uint32_t aProtFlags, + uint32_t* aPrevProtFlags) const { + return ProtectInternal(::VirtualProtect, aVAddress, aSize, aProtFlags, + aPrevProtFlags); + } + + bool FlushInstructionCache() const { + return !!::FlushInstructionCache(::GetCurrentProcess(), nullptr, 0); + } + + static DWORD GetTrampWriteProtFlags() { return PAGE_EXECUTE_READWRITE; } + +#if defined(_M_X64) + bool IsTrampolineSpaceInLowest2GB() const { + return (mBase + mReservationSize) <= + reinterpret_cast<uint8_t*>(0x0000000080000000ULL); + } + + static constexpr bool kSupportsUnwindInfo = true; + + mozilla::UniquePtr<uint8_t[]> LookupUnwindInfo( + uintptr_t aOrigFuncAddr, uint32_t* aOffsetFromBeginAddr, + uint32_t* aOffsetToEndAddr, uintptr_t* aOrigImageBase) const { + DWORD64 origImageBase = 0; + auto origFuncEntry = + RtlLookupFunctionEntry(aOrigFuncAddr, &origImageBase, nullptr); + if (!origFuncEntry) { + return nullptr; + } + + if (aOffsetFromBeginAddr) { + *aOffsetFromBeginAddr = + aOrigFuncAddr - (origImageBase + origFuncEntry->BeginAddress); + } + if (aOffsetToEndAddr) { + *aOffsetToEndAddr = + (origImageBase + origFuncEntry->EndAddress) - aOrigFuncAddr; + } + if (aOrigImageBase) { + *aOrigImageBase = origImageBase; + } + return reinterpret_cast<const UnwindInfo*>(origImageBase + + origFuncEntry->UnwindData) + ->Copy(); + } + + bool AddFunctionTable(uintptr_t aFunctionTable, uint32_t aEntryCount, + uintptr_t aBaseAddress) const { + return bool( + RtlAddFunctionTable(reinterpret_cast<PRUNTIME_FUNCTION>(aFunctionTable), + aEntryCount, aBaseAddress)); + } +#endif // defined(_M_X64) + + protected: + uint8_t* GetLocalView() const { return mBase; } + + uintptr_t GetRemoteView() const { + // Same as local view for in-process + return reinterpret_cast<uintptr_t>(mBase); + } + + /** + * @return the effective number of bytes reserved, or 0 on failure + */ + uint32_t Reserve(const uint32_t aSize, + const Maybe<Span<const uint8_t>>& aBounds) { + if (!aSize) { + return 0; + } + + if (mBase) { + MOZ_ASSERT(mReservationSize >= aSize); + return mReservationSize; + } + + mReservationSize = ComputeAllocationSize(aSize); + + auto reserveFn = [](HANDLE aProcess, PVOID aBase, uint32_t aSize) -> PVOID { + return ::VirtualAlloc(aBase, aSize, MEM_RESERVE, PAGE_NOACCESS); + }; + + auto reserveWithinRangeFn = + [](HANDLE aProcess, uint32_t aSize, const uint8_t* aRangeMin, + const uint8_t* aRangeMaxExcl) -> Maybe<PVOID> { + static const StaticDynamicallyLinkedFunctionPtr< + decltype(&::VirtualAlloc2)> + pVirtualAlloc2(L"kernelbase.dll", "VirtualAlloc2"); + if (!pVirtualAlloc2) { + return Nothing(); + } + + // NB: MEM_ADDRESS_REQUIREMENTS::HighestEndingAddress is *inclusive* + MEM_ADDRESS_REQUIREMENTS memReq = { + const_cast<uint8_t*>(aRangeMin), + const_cast<uint8_t*>(aRangeMaxExcl - 1)}; + + MEM_EXTENDED_PARAMETER memParam = {}; + memParam.Type = MemExtendedParameterAddressRequirements; + memParam.Pointer = &memReq; + + return Some(pVirtualAlloc2(aProcess, nullptr, aSize, MEM_RESERVE, + PAGE_NOACCESS, &memParam, 1)); + }; + + mBase = static_cast<uint8_t*>( + MMPolicyBase::Reserve(::GetCurrentProcess(), mReservationSize, + reserveFn, reserveWithinRangeFn, aBounds)); + + if (!mBase) { + return 0; + } + + return mReservationSize; + } + + bool MaybeCommitNextPage(const uint32_t aRequestedOffset, + const uint32_t aRequestedLength) { + if (!(*this)) { + return false; + } + + uint32_t limit = aRequestedOffset + aRequestedLength - 1; + if (limit < mCommitOffset) { + // No commit required + return true; + } + + MOZ_DIAGNOSTIC_ASSERT(mCommitOffset < mReservationSize); + if (mCommitOffset >= mReservationSize) { + return false; + } + + PVOID local = ::VirtualAlloc(mBase + mCommitOffset, GetPageSize(), + MEM_COMMIT, PAGE_EXECUTE_READ); + if (!local) { + return false; + } + + mCommitOffset += GetPageSize(); + return true; + } + + private: + uint8_t* mBase; + uint32_t mReservationSize; + uint32_t mCommitOffset; +}; + +// This class manages in-process memory access without using functions +// imported from kernel32.dll. Instead, it uses functions in its own +// function table that are provided from outside. +class MMPolicyInProcessEarlyStage : public MMPolicyInProcessPrimitive { + public: + struct Kernel32Exports { + decltype(&::FlushInstructionCache) mFlushInstructionCache; + decltype(&::GetModuleHandleW) mGetModuleHandleW; + decltype(&::GetSystemInfo) mGetSystemInfo; + decltype(&::VirtualProtect) mVirtualProtect; + }; + + private: + static DWORD GetPageSize(const Kernel32Exports& aK32Exports) { + SYSTEM_INFO sysInfo; + aK32Exports.mGetSystemInfo(&sysInfo); + return sysInfo.dwPageSize; + } + + const Kernel32Exports& mK32Exports; + const DWORD mPageSize; + + public: + explicit MMPolicyInProcessEarlyStage(const Kernel32Exports& aK32Exports) + : mK32Exports(aK32Exports), mPageSize(GetPageSize(mK32Exports)) {} + + // The pattern of constructing a local static variable with a lambda, + // which can be seen in MMPolicyBase, is compiled into code with the + // critical section APIs like EnterCriticalSection imported from kernel32.dll. + // Because this class needs to be able to run in a process's early stage + // when IAT is not yet resolved, we cannot use that patten, thus simply + // caching a value as a local member in the class. + DWORD GetPageSize() const { return mPageSize; } + + bool Protect(void* aVAddress, size_t aSize, uint32_t aProtFlags, + uint32_t* aPrevProtFlags) const { + return ProtectInternal(mK32Exports.mVirtualProtect, aVAddress, aSize, + aProtFlags, aPrevProtFlags); + } + + bool FlushInstructionCache() const { + const HANDLE kCurrentProcess = reinterpret_cast<HANDLE>(-1); + return !!mK32Exports.mFlushInstructionCache(kCurrentProcess, nullptr, 0); + } +}; + +class MMPolicyOutOfProcess : public MMPolicyBase { + public: + typedef MMPolicyOutOfProcess MMPolicyT; + + explicit MMPolicyOutOfProcess(HANDLE aProcess) + : mProcess(nullptr), + mMapping(nullptr), + mLocalView(nullptr), + mRemoteView(nullptr), + mReservationSize(0), + mCommitOffset(0) { + MOZ_ASSERT(aProcess); + ::DuplicateHandle(::GetCurrentProcess(), aProcess, ::GetCurrentProcess(), + &mProcess, kAccessFlags, FALSE, 0); + MOZ_ASSERT(mProcess); + } + + explicit MMPolicyOutOfProcess(DWORD aPid) + : mProcess(::OpenProcess(kAccessFlags, FALSE, aPid)), + mMapping(nullptr), + mLocalView(nullptr), + mRemoteView(nullptr), + mReservationSize(0), + mCommitOffset(0) { + MOZ_ASSERT(mProcess); + } + + ~MMPolicyOutOfProcess() { Destroy(); } + + MMPolicyOutOfProcess(MMPolicyOutOfProcess&& aOther) + : mProcess(nullptr), + mMapping(nullptr), + mLocalView(nullptr), + mRemoteView(nullptr), + mReservationSize(0), + mCommitOffset(0) { + *this = std::move(aOther); + } + + MMPolicyOutOfProcess(const MMPolicyOutOfProcess& aOther) = delete; + MMPolicyOutOfProcess& operator=(const MMPolicyOutOfProcess&) = delete; + + MMPolicyOutOfProcess& operator=(MMPolicyOutOfProcess&& aOther) { + Destroy(); + + mProcess = aOther.mProcess; + aOther.mProcess = nullptr; + + mMapping = aOther.mMapping; + aOther.mMapping = nullptr; + + mLocalView = aOther.mLocalView; + aOther.mLocalView = nullptr; + + mRemoteView = aOther.mRemoteView; + aOther.mRemoteView = nullptr; + + mReservationSize = aOther.mReservationSize; + aOther.mReservationSize = 0; + + mCommitOffset = aOther.mCommitOffset; + aOther.mCommitOffset = 0; + + return *this; + } + + explicit operator bool() const { + return mProcess && mMapping && mLocalView && mRemoteView; + } + + bool ShouldUnhookUponDestruction() const { + // We don't clean up hooks for remote processes; they are expected to + // outlive our process. + return false; + } + + // This function reads as many bytes as |aLen| from the target process and + // succeeds only when the entire area to be read is accessible. + bool Read(void* aToPtr, const void* aFromPtr, size_t aLen) const { + MOZ_ASSERT(mProcess); + if (!mProcess) { + return false; + } + + SIZE_T numBytes = 0; + BOOL ok = ::ReadProcessMemory(mProcess, aFromPtr, aToPtr, aLen, &numBytes); + return ok && numBytes == aLen; + } + + // This function reads as many bytes as possible from the target process up + // to |aLen| bytes and returns the number of bytes which was actually read. + size_t TryRead(void* aToPtr, const void* aFromPtr, size_t aLen) const { + MOZ_ASSERT(mProcess); + if (!mProcess) { + return 0; + } + + uint32_t pageSize = GetPageSize(); + uintptr_t pageMask = pageSize - 1; + + auto rangeStart = reinterpret_cast<uintptr_t>(aFromPtr); + auto rangeEnd = rangeStart + aLen; + + while (rangeStart < rangeEnd) { + SIZE_T numBytes = 0; + BOOL ok = ::ReadProcessMemory(mProcess, aFromPtr, aToPtr, + rangeEnd - rangeStart, &numBytes); + if (ok) { + return numBytes; + } + + // If ReadProcessMemory fails, try to read up to each page boundary from + // the end of the requested area one by one. + if (rangeEnd & pageMask) { + rangeEnd &= ~pageMask; + } else { + rangeEnd -= pageSize; + } + } + + return 0; + } + + bool Write(void* aToPtr, const void* aFromPtr, size_t aLen) const { + MOZ_ASSERT(mProcess); + if (!mProcess) { + return false; + } + + SIZE_T numBytes = 0; + BOOL ok = ::WriteProcessMemory(mProcess, aToPtr, aFromPtr, aLen, &numBytes); + return ok && numBytes == aLen; + } + + bool Protect(void* aVAddress, size_t aSize, uint32_t aProtFlags, + uint32_t* aPrevProtFlags) const { + MOZ_ASSERT(mProcess); + if (!mProcess) { + return false; + } + + MOZ_ASSERT(aPrevProtFlags); + BOOL ok = ::VirtualProtectEx(mProcess, aVAddress, aSize, aProtFlags, + reinterpret_cast<PDWORD>(aPrevProtFlags)); + if (!ok && aPrevProtFlags) { + // VirtualProtectEx can fail but still set valid protection flags. + // Let's clear those upon failure. + *aPrevProtFlags = 0; + } + + return !!ok; + } + + /** + * @return true if the page that hosts aVAddress is accessible. + */ + bool IsPageAccessible(uintptr_t aVAddress) const { + MEMORY_BASIC_INFORMATION mbi; + SIZE_T result = nt::VirtualQueryEx( + mProcess, reinterpret_cast<LPCVOID>(aVAddress), &mbi, sizeof(mbi)); + + return result && mbi.AllocationProtect && mbi.State == MEM_COMMIT && + mbi.Protect != PAGE_NOACCESS; + } + + bool FlushInstructionCache() const { + return !!::FlushInstructionCache(mProcess, nullptr, 0); + } + + static DWORD GetTrampWriteProtFlags() { return PAGE_READWRITE; } + +#if defined(_M_X64) + bool IsTrampolineSpaceInLowest2GB() const { + return (GetRemoteView() + mReservationSize) <= 0x0000000080000000ULL; + } + + // TODO: We should also implement unwind info for our out-of-process policy. + static constexpr bool kSupportsUnwindInfo = false; + + inline mozilla::UniquePtr<uint8_t[]> LookupUnwindInfo( + uintptr_t aOrigFuncAddr, uint32_t* aOffsetFromBeginAddr, + uint32_t* aOffsetToEndAddr, uintptr_t* aOrigImageBase) const { + return nullptr; + } + + inline bool AddFunctionTable(uintptr_t aNewTable, uint32_t aEntryCount, + uintptr_t aBaseAddress) const { + return false; + } +#endif // defined(_M_X64) + + protected: + uint8_t* GetLocalView() const { return mLocalView; } + + uintptr_t GetRemoteView() const { + return reinterpret_cast<uintptr_t>(mRemoteView); + } + + /** + * @return the effective number of bytes reserved, or 0 on failure + */ + uint32_t Reserve(const uint32_t aSize, + const Maybe<Span<const uint8_t>>& aBounds) { + if (!aSize || !mProcess) { + SetLastDetourError(MMPOLICY_RESERVE_INVALIDARG); + return 0; + } + + if (mRemoteView) { + MOZ_ASSERT(mReservationSize >= aSize); + SetLastDetourError(MMPOLICY_RESERVE_ZERO_RESERVATIONSIZE); + return mReservationSize; + } + + mReservationSize = ComputeAllocationSize(aSize); + + mMapping = ::CreateFileMappingW(INVALID_HANDLE_VALUE, nullptr, + PAGE_EXECUTE_READWRITE | SEC_RESERVE, 0, + mReservationSize, nullptr); + if (!mMapping) { + SetLastDetourError(MMPOLICY_RESERVE_CREATEFILEMAPPING, ::GetLastError()); + return 0; + } + + mLocalView = static_cast<uint8_t*>( + ::MapViewOfFile(mMapping, FILE_MAP_WRITE, 0, 0, 0)); + if (!mLocalView) { + SetLastDetourError(MMPOLICY_RESERVE_MAPVIEWOFFILE, ::GetLastError()); + return 0; + } + + auto reserveFn = [mapping = mMapping](HANDLE aProcess, PVOID aBase, + uint32_t aSize) -> PVOID { + return mozilla::MapRemoteViewOfFile(mapping, aProcess, 0ULL, aBase, 0, 0, + PAGE_EXECUTE_READ); + }; + + auto reserveWithinRangeFn = + [mapping = mMapping](HANDLE aProcess, uint32_t aSize, + const uint8_t* aRangeMin, + const uint8_t* aRangeMaxExcl) -> Maybe<PVOID> { + static const StaticDynamicallyLinkedFunctionPtr< + decltype(&::MapViewOfFile3)> + pMapViewOfFile3(L"kernelbase.dll", "MapViewOfFile3"); + if (!pMapViewOfFile3) { + return Nothing(); + } + + // NB: MEM_ADDRESS_REQUIREMENTS::HighestEndingAddress is *inclusive* + MEM_ADDRESS_REQUIREMENTS memReq = { + const_cast<uint8_t*>(aRangeMin), + const_cast<uint8_t*>(aRangeMaxExcl - 1)}; + + MEM_EXTENDED_PARAMETER memParam = {}; + memParam.Type = MemExtendedParameterAddressRequirements; + memParam.Pointer = &memReq; + + return Some(pMapViewOfFile3(mapping, aProcess, nullptr, 0, aSize, 0, + PAGE_EXECUTE_READ, &memParam, 1)); + }; + + mRemoteView = MMPolicyBase::Reserve(mProcess, mReservationSize, reserveFn, + reserveWithinRangeFn, aBounds); + if (!mRemoteView) { + return 0; + } + + return mReservationSize; + } + + bool MaybeCommitNextPage(const uint32_t aRequestedOffset, + const uint32_t aRequestedLength) { + if (!(*this)) { + return false; + } + + uint32_t limit = aRequestedOffset + aRequestedLength - 1; + if (limit < mCommitOffset) { + // No commit required + return true; + } + + MOZ_DIAGNOSTIC_ASSERT(mCommitOffset < mReservationSize); + if (mCommitOffset >= mReservationSize) { + return false; + } + + PVOID local = ::VirtualAlloc(mLocalView + mCommitOffset, GetPageSize(), + MEM_COMMIT, PAGE_READWRITE); + if (!local) { + return false; + } + + PVOID remote = ::VirtualAllocEx( + mProcess, static_cast<uint8_t*>(mRemoteView) + mCommitOffset, + GetPageSize(), MEM_COMMIT, PAGE_EXECUTE_READ); + if (!remote) { + return false; + } + + mCommitOffset += GetPageSize(); + return true; + } + + private: + void Destroy() { + // We always leak the remote view + if (mLocalView) { + ::UnmapViewOfFile(mLocalView); + mLocalView = nullptr; + } + + if (mMapping) { + ::CloseHandle(mMapping); + mMapping = nullptr; + } + + if (mProcess) { + ::CloseHandle(mProcess); + mProcess = nullptr; + } + } + + private: + HANDLE mProcess; + HANDLE mMapping; + uint8_t* mLocalView; + PVOID mRemoteView; + uint32_t mReservationSize; + uint32_t mCommitOffset; + + static const DWORD kAccessFlags = PROCESS_QUERY_INFORMATION | + PROCESS_VM_OPERATION | PROCESS_VM_READ | + PROCESS_VM_WRITE; +}; + +} // namespace interceptor +} // namespace mozilla + +#endif // mozilla_interceptor_MMPolicies_h |