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diff --git a/toolkit/xre/dllservices/mozglue/interceptor/Trampoline.h b/toolkit/xre/dllservices/mozglue/interceptor/Trampoline.h
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+/* -*- 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_Trampoline_h
+#define mozilla_interceptor_Trampoline_h
+
+#include "mozilla/Assertions.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/CheckedInt.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/Types.h"
+#include "mozilla/WindowsProcessMitigations.h"
+#include "mozilla/WindowsUnwindInfo.h"
+
+namespace mozilla {
+namespace interceptor {
+
+template <typename MMPolicy>
+class MOZ_STACK_CLASS Trampoline final {
+ public:
+ Trampoline(const MMPolicy* aMMPolicy, uint8_t* const aLocalBase,
+ const uintptr_t aRemoteBase, const uint32_t aChunkSize)
+ : mMMPolicy(aMMPolicy),
+ mPrevLocalProt(0),
+ mLocalBase(aLocalBase),
+ mRemoteBase(aRemoteBase),
+ mOffset(0),
+ mExeOffset(0),
+#ifdef _M_X64
+ mCopyCodesEndOffset(0),
+ mExeEndOffset(0),
+#endif // _M_X64
+ mMaxOffset(aChunkSize),
+ mAccumulatedStatus(true) {
+ if (!::VirtualProtect(aLocalBase, aChunkSize,
+ MMPolicy::GetTrampWriteProtFlags(),
+ &mPrevLocalProt)) {
+ mPrevLocalProt = 0;
+ }
+ }
+
+ Trampoline(Trampoline&& aOther)
+ : mMMPolicy(aOther.mMMPolicy),
+ mPrevLocalProt(aOther.mPrevLocalProt),
+ mLocalBase(aOther.mLocalBase),
+ mRemoteBase(aOther.mRemoteBase),
+ mOffset(aOther.mOffset),
+ mExeOffset(aOther.mExeOffset),
+#ifdef _M_X64
+ mCopyCodesEndOffset(aOther.mCopyCodesEndOffset),
+ mExeEndOffset(aOther.mExeEndOffset),
+#endif // _M_X64
+ mMaxOffset(aOther.mMaxOffset),
+ mAccumulatedStatus(aOther.mAccumulatedStatus) {
+ aOther.mPrevLocalProt = 0;
+ aOther.mAccumulatedStatus = false;
+ }
+
+ MOZ_IMPLICIT Trampoline(decltype(nullptr))
+ : mMMPolicy(nullptr),
+ mPrevLocalProt(0),
+ mLocalBase(nullptr),
+ mRemoteBase(0),
+ mOffset(0),
+ mExeOffset(0),
+#ifdef _M_X64
+ mCopyCodesEndOffset(0),
+ mExeEndOffset(0),
+#endif // _M_X64
+ mMaxOffset(0),
+ mAccumulatedStatus(false) {
+ }
+
+ Trampoline(const Trampoline&) = delete;
+ Trampoline& operator=(const Trampoline&) = delete;
+
+ Trampoline& operator=(Trampoline&& aOther) {
+ Clear();
+
+ mMMPolicy = aOther.mMMPolicy;
+ mPrevLocalProt = aOther.mPrevLocalProt;
+ mLocalBase = aOther.mLocalBase;
+ mRemoteBase = aOther.mRemoteBase;
+ mOffset = aOther.mOffset;
+ mExeOffset = aOther.mExeOffset;
+#ifdef _M_X64
+ mCopyCodesEndOffset = aOther.mCopyCodesEndOffset;
+ mExeEndOffset = aOther.mExeEndOffset;
+#endif // _M_X64
+ mMaxOffset = aOther.mMaxOffset;
+ mAccumulatedStatus = aOther.mAccumulatedStatus;
+
+ aOther.mPrevLocalProt = 0;
+ aOther.mAccumulatedStatus = false;
+
+ return *this;
+ }
+
+ ~Trampoline() { Clear(); }
+
+ explicit operator bool() const {
+ return IsNull() ||
+ (mLocalBase && mRemoteBase && mPrevLocalProt && mAccumulatedStatus);
+ }
+
+ bool IsNull() const { return !mMMPolicy; }
+
+#if defined(_M_ARM64)
+
+ void WriteInstruction(uint32_t aInstruction) {
+ const uint32_t kDelta = sizeof(uint32_t);
+
+ if (!mMMPolicy) {
+ // Null tramp, just track offset
+ mOffset += kDelta;
+ return;
+ }
+
+ if (mOffset + kDelta > mMaxOffset) {
+ mAccumulatedStatus = false;
+ return;
+ }
+
+ *reinterpret_cast<uint32_t*>(mLocalBase + mOffset) = aInstruction;
+ mOffset += kDelta;
+ }
+
+ void WriteLoadLiteral(const uintptr_t aAddress, const uint8_t aReg) {
+ const uint32_t kDelta = sizeof(uint32_t) + sizeof(uintptr_t);
+
+ if (!mMMPolicy) {
+ // Null tramp, just track offset
+ mOffset += kDelta;
+ return;
+ }
+
+ // We grow the literal pool from the *end* of the tramp,
+ // so we need to ensure that there is enough room for both an instruction
+ // and a pointer
+ if (mOffset + kDelta > mMaxOffset) {
+ mAccumulatedStatus = false;
+ return;
+ }
+
+ mMaxOffset -= sizeof(uintptr_t);
+ *reinterpret_cast<uintptr_t*>(mLocalBase + mMaxOffset) = aAddress;
+
+ CheckedInt<intptr_t> pc(GetCurrentRemoteAddress());
+ if (!pc.isValid()) {
+ mAccumulatedStatus = false;
+ return;
+ }
+
+ CheckedInt<intptr_t> literal(reinterpret_cast<uintptr_t>(mLocalBase) +
+ mMaxOffset);
+ if (!literal.isValid()) {
+ mAccumulatedStatus = false;
+ return;
+ }
+
+ CheckedInt<intptr_t> ptrOffset = (literal - pc);
+ if (!ptrOffset.isValid()) {
+ mAccumulatedStatus = false;
+ return;
+ }
+
+ // ptrOffset must be properly aligned
+ MOZ_ASSERT((ptrOffset.value() % 4) == 0);
+ ptrOffset /= 4;
+
+ CheckedInt<int32_t> offset(ptrOffset.value());
+ if (!offset.isValid()) {
+ mAccumulatedStatus = false;
+ return;
+ }
+
+ // Ensure that offset falls within the range of a signed 19-bit value
+ if (offset.value() < -0x40000 || offset.value() > 0x3FFFF) {
+ mAccumulatedStatus = false;
+ return;
+ }
+
+ const int32_t kimm19Mask = 0x7FFFF;
+ int32_t masked = offset.value() & kimm19Mask;
+
+ MOZ_ASSERT(aReg < 32);
+ uint32_t loadInstr = 0x58000000 | (masked << 5) | aReg;
+ WriteInstruction(loadInstr);
+ }
+
+#else
+
+ void WriteByte(uint8_t aValue) {
+ const uint32_t kDelta = sizeof(uint8_t);
+
+ if (!mMMPolicy) {
+ // Null tramp, just track offset
+ mOffset += kDelta;
+ return;
+ }
+
+ if (mOffset >= mMaxOffset) {
+ mAccumulatedStatus = false;
+ return;
+ }
+
+ *(mLocalBase + mOffset) = aValue;
+ ++mOffset;
+ }
+
+ void WriteInteger(int32_t aValue) {
+ const uint32_t kDelta = sizeof(int32_t);
+
+ if (!mMMPolicy) {
+ // Null tramp, just track offset
+ mOffset += kDelta;
+ return;
+ }
+
+ if (mOffset + kDelta > mMaxOffset) {
+ mAccumulatedStatus = false;
+ return;
+ }
+
+ *reinterpret_cast<int32_t*>(mLocalBase + mOffset) = aValue;
+ mOffset += kDelta;
+ }
+
+ void WriteDisp32(uintptr_t aAbsTarget) {
+ const uint32_t kDelta = sizeof(int32_t);
+
+ if (!mMMPolicy) {
+ // Null tramp, just track offset
+ mOffset += kDelta;
+ return;
+ }
+
+ if (mOffset + kDelta > mMaxOffset) {
+ mAccumulatedStatus = false;
+ return;
+ }
+
+ // This needs to be computed from the remote location
+ intptr_t remoteTrampPosition = static_cast<intptr_t>(mRemoteBase + mOffset);
+
+ intptr_t diff =
+ static_cast<intptr_t>(aAbsTarget) - (remoteTrampPosition + kDelta);
+
+ CheckedInt<int32_t> checkedDisp(diff);
+ MOZ_ASSERT(checkedDisp.isValid());
+ if (!checkedDisp.isValid()) {
+ mAccumulatedStatus = false;
+ return;
+ }
+
+ int32_t disp = checkedDisp.value();
+ *reinterpret_cast<int32_t*>(mLocalBase + mOffset) = disp;
+ mOffset += kDelta;
+ }
+
+ void WriteBytes(void* aAddr, size_t aSize) {
+ if (!mMMPolicy) {
+ // Null tramp, just track offset
+ mOffset += aSize;
+ return;
+ }
+
+ if (mOffset + aSize > mMaxOffset) {
+ mAccumulatedStatus = false;
+ return;
+ }
+
+ std::memcpy(reinterpret_cast<void*>(mLocalBase + mOffset), aAddr, aSize);
+ mOffset += aSize;
+ }
+
+#endif
+
+ void WritePointer(uintptr_t aValue) {
+ const uint32_t kDelta = sizeof(uintptr_t);
+
+ if (!mMMPolicy) {
+ // Null tramp, just track offset
+ mOffset += kDelta;
+ return;
+ }
+
+ if (mOffset + kDelta > mMaxOffset) {
+ mAccumulatedStatus = false;
+ return;
+ }
+
+ *reinterpret_cast<uintptr_t*>(mLocalBase + mOffset) = aValue;
+ mOffset += kDelta;
+ }
+
+ void WriteEncodedPointer(void* aValue) {
+ uintptr_t encoded = ReadOnlyTargetFunction<MMPolicy>::EncodePtr(aValue);
+ WritePointer(encoded);
+ }
+
+ Maybe<uintptr_t> ReadPointer() {
+ if (mOffset + sizeof(uintptr_t) > mMaxOffset) {
+ mAccumulatedStatus = false;
+ return Nothing();
+ }
+
+ auto result = Some(*reinterpret_cast<uintptr_t*>(mLocalBase + mOffset));
+ mOffset += sizeof(uintptr_t);
+ return std::move(result);
+ }
+
+ Maybe<uintptr_t> ReadEncodedPointer() {
+ Maybe<uintptr_t> encoded(ReadPointer());
+ if (!encoded) {
+ return encoded;
+ }
+
+ return Some(ReadOnlyTargetFunction<MMPolicy>::DecodePtr(encoded.value()));
+ }
+
+#if defined(_M_IX86)
+ // 32-bit only
+ void AdjustDisp32AtOffset(uint32_t aOffset, uintptr_t aAbsTarget) {
+ uint32_t effectiveOffset = mExeOffset + aOffset;
+
+ if (effectiveOffset + sizeof(int32_t) > mMaxOffset) {
+ mAccumulatedStatus = false;
+ return;
+ }
+
+ intptr_t diff = static_cast<intptr_t>(aAbsTarget) -
+ static_cast<intptr_t>(mRemoteBase + mExeOffset);
+ *reinterpret_cast<int32_t*>(mLocalBase + effectiveOffset) += diff;
+ }
+#endif // defined(_M_IX86)
+
+ void CopyFrom(uintptr_t aOrigBytes, uint32_t aNumBytes) {
+ if (!mMMPolicy) {
+ // Null tramp, just track offset
+ mOffset += aNumBytes;
+ return;
+ }
+
+ if (!mMMPolicy || mOffset + aNumBytes > mMaxOffset) {
+ mAccumulatedStatus = false;
+ return;
+ }
+
+ if (!mMMPolicy->Read(mLocalBase + mOffset,
+ reinterpret_cast<void*>(aOrigBytes), aNumBytes)) {
+ mAccumulatedStatus = false;
+ return;
+ }
+
+ mOffset += aNumBytes;
+ }
+
+ void CopyCodes(uintptr_t aOrigBytes, uint32_t aNumBytes) {
+#ifdef _M_X64
+ if (mOffset == mCopyCodesEndOffset) {
+ mCopyCodesEndOffset += aNumBytes;
+ }
+#endif // _M_X64
+ CopyFrom(aOrigBytes, aNumBytes);
+ }
+
+ void Rewind() { mOffset = 0; }
+
+ uintptr_t GetCurrentRemoteAddress() const { return mRemoteBase + mOffset; }
+
+ void StartExecutableCode() {
+ MOZ_ASSERT(!mExeOffset);
+ mExeOffset = mOffset;
+#ifdef _M_X64
+ mCopyCodesEndOffset = mOffset;
+#endif // _M_X64
+ }
+
+ void* EndExecutableCode() {
+ if (!mAccumulatedStatus || !mMMPolicy) {
+ return nullptr;
+ }
+
+#ifdef _M_X64
+ mExeEndOffset = mOffset;
+#endif // _M_X64
+
+ // This must always return the start address the executable code
+ // *in the target process*
+ return reinterpret_cast<void*>(mRemoteBase + mExeOffset);
+ }
+
+ uint32_t GetCurrentExecutableCodeLen() const { return mOffset - mExeOffset; }
+
+#ifdef _M_X64
+
+ void Align(uint32_t aAlignment) {
+ // aAlignment should be a power of 2
+ MOZ_ASSERT(!(aAlignment & (aAlignment - 1)));
+
+ uint32_t alignedOffset = (mOffset + aAlignment - 1) & ~(aAlignment - 1);
+ if (alignedOffset > mMaxOffset) {
+ mAccumulatedStatus = false;
+ return;
+ }
+ mOffset = alignedOffset;
+ }
+
+ // We assume that all instructions that are part of the prologue are left
+ // intact by detouring code, i.e. that they are copied using CopyCodes. This
+ // is not true for calls and jumps for example, but calls and jumps cannot be
+ // part of the prologue. This assumption allows us to copy unwind information
+ // as-is, because unwind information only refers to instructions within the
+ // prologue.
+ bool AddUnwindInfo(uintptr_t aOrigFuncAddr, uintptr_t aOrigFuncStopOffset) {
+ if constexpr (!MMPolicy::kSupportsUnwindInfo) {
+ return false;
+ }
+
+ if (!mMMPolicy) {
+ return false;
+ }
+
+ uint32_t origFuncOffsetFromBeginAddr = 0;
+ uint32_t origFuncOffsetToEndAddr = 0;
+ uintptr_t origImageBase = 0;
+ auto unwindInfoData =
+ mMMPolicy->LookupUnwindInfo(aOrigFuncAddr, &origFuncOffsetFromBeginAddr,
+ &origFuncOffsetToEndAddr, &origImageBase);
+ if (!unwindInfoData) {
+ // If the original function does not have unwind info, there is nothing
+ // more to do.
+ return true;
+ }
+
+ // We do not support hooking at a location that isn't the beginning of a
+ // function.
+ MOZ_ASSERT(origFuncOffsetFromBeginAddr == 0);
+ if (origFuncOffsetFromBeginAddr != 0) {
+ return false;
+ }
+
+ IterableUnwindInfo unwindInfoIt(unwindInfoData.get());
+ auto& unwindInfo = unwindInfoIt.Info();
+
+ // The prologue should contain only instructions that we detour using
+ // CopyCodes. If not, there is most likely a mismatch between the unwind
+ // information and the actual code we are detouring, so we stop here. This
+ // is a best-effort safeguard intended to detect situations where e.g.
+ // third-party injected code would have altered the function we are
+ // detouring.
+ if (mCopyCodesEndOffset < aOrigFuncStopOffset &&
+ unwindInfo.size_of_prolog > mCopyCodesEndOffset) {
+ return false;
+ }
+
+ // According to the documentation, the array is sorted by descending order
+ // of offset in the prologue. Let's double check this assumption if in
+ // debug. This also checks that the full unwind information isn't
+ // ill-formed, thanks to all the MOZ_ASSERT in iteration code.
+# ifdef DEBUG
+ uint8_t previousOffset = 0xFF;
+ for (const auto& unwindCode : unwindInfoIt) {
+ MOZ_ASSERT(unwindCode.offset_in_prolog <= previousOffset);
+ previousOffset = unwindCode.offset_in_prolog;
+ }
+# endif // DEBUG
+
+ // We skip entries that are not part of the code we have detoured.
+ // This code relies on the array being sorted by descending order of offset
+ // in the prolog.
+ uint8_t firstRelevantCode = 0;
+ uint8_t countOfCodes = 0;
+ auto it = unwindInfoIt.begin();
+ for (; it != unwindInfoIt.end(); ++it) {
+ const auto& unwindCode = *it;
+ if (unwindCode.offset_in_prolog <= aOrigFuncStopOffset) {
+ // Found a relevant entry
+ firstRelevantCode = it.Index();
+ countOfCodes = unwindInfo.count_of_codes - firstRelevantCode;
+ break;
+ }
+ }
+
+ // Check that we encountered no ill-formed unwind codes.
+ if (!it.IsValid() && !it.IsAtEnd()) {
+ return false;
+ }
+
+ // We do not support chained unwind info. We should add support for chained
+ // unwind info if we ever reach this assert. Since we hook functions at
+ // their start address, this should not happen.
+ if (unwindInfo.flags & UNW_FLAG_CHAININFO) {
+ MOZ_ASSERT(
+ false,
+ "Tried to detour at a location with chained unwind information");
+ return false;
+ }
+
+ // We do not support exception handler info either. This could be a problem
+ // if we detour code that does not belong to the prologue and contains a
+ // call instruction, as this handler would then not be found if unwinding
+ // from callees. The following assert checks that this does not happen.
+ //
+ // Our current assumption is that all the functions we hook either have no
+ // associated exception handlers, or it is __GSHandlerCheck. This handler
+ // is the most commonly found, for example it is present in LdrLoadDll,
+ // SendMessageTimeoutW, GetWindowInfo. It is added to functions that use
+ // stack buffers, in order to mitigate stack buffer overflows. We explain
+ // below why it is not a problem that we do not preserve __GSHandlerCheck
+ // information when we detour code.
+ //
+ // Preserving exception handler information would raise two challenges:
+ //
+ // (1) if the exception handler was not written in a generic way, it may
+ // behave differently when called for our detoured code compared to
+ // what it would do if called from the original location of the code;
+ // (2) the exception handler can be followed by handler-specific data,
+ // which we cannot copy because we do not know its size.
+ //
+ // __GSHandlerCheck checks that the stack cookie value wasn't overwritten
+ // before continuing to unwind and call further handlers. That is a
+ // security feature that we want to preserve. However, since these
+ // functions allocate stack space and write the stack cookie as part of
+ // their prologue, the 13 bytes that we detour are necessarily part of
+ // their prologue, which must contain at least the following instructions:
+ //
+ // 48 81 ec XX XX XX XX sub rsp, 0xXXXXXXXX
+ // 48 8b 05 XX XX XX XX mov rax, qword ptr [rip+__security_cookie]
+ // 48 33 c4 xor rax, rsp
+ // 48 89 84 24 XX XX XX XX mov qword ptr [RSP + 0xXXXXXXXX],RAX
+ //
+ // As a consequence, code associated with __GSHandlerCheck will necessarily
+ // satisfy (aOrigFuncStopOffset <= unwindInfo.size_of_prolog), and it is OK
+ // to not preserve handler info in that case.
+# ifdef DEBUG
+ if (aOrigFuncStopOffset > unwindInfo.size_of_prolog) {
+ MOZ_ASSERT(!(unwindInfo.flags & (UNW_FLAG_EHANDLER | UNW_FLAG_UHANDLER)));
+ }
+# endif // DEBUG
+
+ // The unwind info must be DWORD-aligned
+ Align(sizeof(uint32_t));
+ if (!mAccumulatedStatus) {
+ return false;
+ }
+ uintptr_t unwindInfoOffset = mOffset;
+
+ unwindInfo.flags &=
+ ~(UNW_FLAG_CHAININFO | UNW_FLAG_EHANDLER | UNW_FLAG_UHANDLER);
+ unwindInfo.count_of_codes = countOfCodes;
+ if (aOrigFuncStopOffset < unwindInfo.size_of_prolog) {
+ unwindInfo.size_of_prolog = aOrigFuncStopOffset;
+ }
+
+ WriteBytes(reinterpret_cast<void*>(&unwindInfo),
+ offsetof(UnwindInfo, unwind_code));
+ if (!mAccumulatedStatus) {
+ return false;
+ }
+
+ WriteBytes(
+ reinterpret_cast<void*>(&unwindInfo.unwind_code[firstRelevantCode]),
+ countOfCodes * sizeof(UnwindCode));
+ if (!mAccumulatedStatus) {
+ return false;
+ }
+
+ // The function table must be DWORD-aligned
+ Align(sizeof(uint32_t));
+ if (!mAccumulatedStatus) {
+ return false;
+ }
+ uintptr_t functionTableOffset = mOffset;
+
+ WriteInteger(mExeOffset);
+ if (!mAccumulatedStatus) {
+ return false;
+ }
+
+ WriteInteger(mExeEndOffset);
+ if (!mAccumulatedStatus) {
+ return false;
+ }
+
+ WriteInteger(unwindInfoOffset);
+ if (!mAccumulatedStatus) {
+ return false;
+ }
+
+ return mMMPolicy->AddFunctionTable(mRemoteBase + functionTableOffset, 1,
+ mRemoteBase);
+ }
+
+#endif // _M_X64
+
+ Trampoline<MMPolicy>& operator--() {
+ MOZ_ASSERT(mOffset);
+ --mOffset;
+ return *this;
+ }
+
+ private:
+ void Clear() {
+ if (!mLocalBase || !mPrevLocalProt) {
+ return;
+ }
+
+ DebugOnly<bool> ok = !!::VirtualProtect(mLocalBase, mMaxOffset,
+ mPrevLocalProt, &mPrevLocalProt);
+ MOZ_ASSERT(ok);
+
+ mLocalBase = nullptr;
+ mRemoteBase = 0;
+ mPrevLocalProt = 0;
+ mAccumulatedStatus = false;
+ }
+
+ private:
+ const MMPolicy* mMMPolicy;
+ DWORD mPrevLocalProt;
+ uint8_t* mLocalBase;
+ uintptr_t mRemoteBase;
+ uint32_t mOffset;
+ uint32_t mExeOffset;
+#ifdef _M_X64
+ uint32_t mCopyCodesEndOffset;
+ uint32_t mExeEndOffset;
+#endif // _M_X64
+ uint32_t mMaxOffset;
+ bool mAccumulatedStatus;
+};
+
+template <typename MMPolicy>
+class MOZ_STACK_CLASS TrampolineCollection final {
+ public:
+ class MOZ_STACK_CLASS TrampolineIterator final {
+ public:
+ Trampoline<MMPolicy> operator*() {
+ uint32_t offset = mCurTramp * mCollection.mTrampSize;
+ return Trampoline<MMPolicy>(
+ &mCollection.mMMPolicy, mCollection.mLocalBase + offset,
+ mCollection.mRemoteBase + offset, mCollection.mTrampSize);
+ }
+
+ TrampolineIterator& operator++() {
+ ++mCurTramp;
+ return *this;
+ }
+
+ bool operator!=(const TrampolineIterator& aOther) const {
+ return mCurTramp != aOther.mCurTramp;
+ }
+
+ private:
+ explicit TrampolineIterator(
+ const TrampolineCollection<MMPolicy>& aCollection,
+ const uint32_t aCurTramp = 0)
+ : mCollection(aCollection), mCurTramp(aCurTramp) {}
+
+ const TrampolineCollection<MMPolicy>& mCollection;
+ uint32_t mCurTramp;
+
+ friend class TrampolineCollection<MMPolicy>;
+ };
+
+ explicit TrampolineCollection(const MMPolicy& aMMPolicy)
+ : mMMPolicy(aMMPolicy),
+ mLocalBase(0),
+ mRemoteBase(0),
+ mTrampSize(0),
+ mNumTramps(0),
+ mPrevProt(0),
+ mCS(nullptr) {}
+
+ TrampolineCollection(const MMPolicy& aMMPolicy, uint8_t* const aLocalBase,
+ const uintptr_t aRemoteBase, const uint32_t aTrampSize,
+ const uint32_t aNumTramps)
+ : mMMPolicy(aMMPolicy),
+ mLocalBase(aLocalBase),
+ mRemoteBase(aRemoteBase),
+ mTrampSize(aTrampSize),
+ mNumTramps(aNumTramps),
+ mPrevProt(0),
+ mCS(nullptr) {
+ if (!aNumTramps) {
+ return;
+ }
+
+ BOOL ok = mMMPolicy.Protect(aLocalBase, aNumTramps * aTrampSize,
+ PAGE_EXECUTE_READWRITE, &mPrevProt);
+ if (!ok) {
+ // When destroying a sandboxed process that uses
+ // MITIGATION_DYNAMIC_CODE_DISABLE, we won't be allowed to write to our
+ // executable memory so we just do nothing. If we fail to get access
+ // to memory for any other reason, we still don't want to crash but we
+ // do assert.
+ MOZ_ASSERT(IsDynamicCodeDisabled());
+ mNumTramps = 0;
+ mPrevProt = 0;
+ }
+ }
+
+ ~TrampolineCollection() {
+ if (!mPrevProt) {
+ return;
+ }
+
+ mMMPolicy.Protect(mLocalBase, mNumTramps * mTrampSize, mPrevProt,
+ &mPrevProt);
+
+ if (mCS) {
+ ::LeaveCriticalSection(mCS);
+ }
+ }
+
+ void Lock(CRITICAL_SECTION& aCS) {
+ if (!mPrevProt || mCS) {
+ return;
+ }
+
+ mCS = &aCS;
+ ::EnterCriticalSection(&aCS);
+ }
+
+ TrampolineIterator begin() const {
+ if (!mPrevProt) {
+ return end();
+ }
+
+ return TrampolineIterator(*this);
+ }
+
+ TrampolineIterator end() const {
+ return TrampolineIterator(*this, mNumTramps);
+ }
+
+ TrampolineCollection(const TrampolineCollection&) = delete;
+ TrampolineCollection& operator=(const TrampolineCollection&) = delete;
+ TrampolineCollection& operator=(TrampolineCollection&&) = delete;
+
+ TrampolineCollection(TrampolineCollection&& aOther)
+ : mMMPolicy(aOther.mMMPolicy),
+ mLocalBase(aOther.mLocalBase),
+ mRemoteBase(aOther.mRemoteBase),
+ mTrampSize(aOther.mTrampSize),
+ mNumTramps(aOther.mNumTramps),
+ mPrevProt(aOther.mPrevProt),
+ mCS(aOther.mCS) {
+ aOther.mPrevProt = 0;
+ aOther.mCS = nullptr;
+ }
+
+ private:
+ const MMPolicy& mMMPolicy;
+ uint8_t* const mLocalBase;
+ const uintptr_t mRemoteBase;
+ const uint32_t mTrampSize;
+ uint32_t mNumTramps;
+ uint32_t mPrevProt;
+ CRITICAL_SECTION* mCS;
+
+ friend class TrampolineIterator;
+};
+
+} // namespace interceptor
+} // namespace mozilla
+
+#endif // mozilla_interceptor_Trampoline_h