Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

56 files changed, 4495 insertions, 0 deletions

diff --git a/toolkit/xre/dllservices/tests/AssemblyPayloads.h b/toolkit/xre/dllservices/tests/AssemblyPayloads.h
new file mode 100644
index 0000000000..4dcbcc5fbf
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/AssemblyPayloads.h
@@ -0,0 +1,238 @@
+/* -*- 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/. */
+
+/* These assembly functions represent patterns that were already hooked by
+ * another application before our detour.
+ */
+
+#ifndef mozilla_AssemblyPayloads_h
+#define mozilla_AssemblyPayloads_h
+
+#include <cstdint>
+
+#define PADDING_256_NOP                                              \
+  "nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;" \
+  "nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;" \
+  "nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;" \
+  "nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;" \
+  "nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;" \
+  "nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;" \
+  "nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;" \
+  "nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;" \
+  "nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;" \
+  "nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;" \
+  "nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;" \
+  "nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;" \
+  "nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;" \
+  "nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;" \
+  "nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;" \
+  "nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;"
+
+extern "C" {
+
+#if defined(__clang__)
+#  if defined(_M_X64)
+constexpr uintptr_t JumpDestination = 0x7fff00000000;
+
+__declspec(dllexport) __attribute__((naked)) void MovPushRet() {
+  asm volatile(
+      "mov %0, %%rax;"
+      "push %%rax;"
+      "ret;"
+      :
+      : "i"(JumpDestination));
+}
+
+__declspec(dllexport) __attribute__((naked)) void MovRaxJump() {
+  asm volatile(
+      "mov %0, %%rax;"
+      "jmpq *%%rax;"
+      :
+      : "i"(JumpDestination));
+}
+
+__declspec(dllexport) __attribute__((naked)) void DoubleJump() {
+  asm volatile(
+      "jmp label1;"
+
+      "label2:"
+      "mov %0, %%rax;"
+      "jmpq *%%rax;"
+
+      // 0x100 bytes padding to generate jmp rel32 instead of jmp rel8
+      PADDING_256_NOP
+
+      "label1:"
+      "jmp label2;"
+      :
+      : "i"(JumpDestination));
+}
+
+__declspec(dllexport) __attribute__((naked)) void NearJump() {
+  asm volatile(
+      "jae label3;"
+      "je  label3;"
+      "jne label3;"
+
+      "label4:"
+      "mov %0, %%rax;"
+      "jmpq *%%rax;"
+
+      // 0x100 bytes padding to generate jae rel32 instead of jae rel8
+      PADDING_256_NOP
+
+      "label3:"
+      "jmp label4;"
+      :
+      : "i"(JumpDestination));
+}
+
+__declspec(dllexport) __attribute__((naked)) void OpcodeFF() {
+  // Skip PUSH (FF /6) because clang prefers Opcode 50+rd
+  // to translate PUSH r64 rather than Opcode FF.
+  asm volatile(
+      "incl %eax;"
+      "decl %ebx;"
+      "call *%rcx;"
+      "jmp *(%rip);"  // Indirect jump to 0xcccccccc`cccccccc
+      "int $3;int $3;int $3;int $3;"
+      "int $3;int $3;int $3;int $3;");
+}
+
+__declspec(dllexport) __attribute__((naked)) void IndirectCall() {
+  asm volatile(
+      "call *(%rip);"  // Indirect call to 0x90909090`90909090
+      "nop;nop;nop;nop;nop;nop;nop;nop;"
+      "ret;");
+}
+
+__declspec(dllexport) __attribute__((naked)) void MovImm64() {
+  asm volatile(
+      "mov $0x1234567812345678, %r10;"
+      "nop;nop;nop");
+}
+
+#    if !defined(MOZ_CODE_COVERAGE)
+// This code reproduces bug 1798787: it uses the same prologue, the same unwind
+// info, and it has a call instruction that starts within the 13 first bytes.
+__attribute__((naked)) void DetouredCallCode(uintptr_t aCallee) {
+  asm volatile(
+      "subq $0x28, %rsp;"
+      "testq %rcx, %rcx;"
+      "jz exit;"
+      "callq *%rcx;"
+      "exit:"
+      "addq $0x28, %rsp;"
+      "retq;");
+}
+constexpr uint8_t gDetouredCallCodeSize = 16;  // size of function in bytes
+alignas(uint32_t) uint8_t gDetouredCallUnwindInfo[] = {
+    0x01,  // Version (1), Flags (0)
+    0x04,  // SizeOfProlog (4)
+    0x01,  // CountOfUnwindCodes (1)
+    0x00,  // FrameRegister (0), FrameOffset (0)
+    // UnwindCodes[0]
+    0x04,  // .OffsetInProlog (4)
+    0x42,  // .UnwindOpCode(UWOP_ALLOC_SMALL=2), .UnwindInfo (4)
+};
+
+// This points to the same code as DetouredCallCode, but dynamically generated
+// so that it can have custom unwinding info. See TestDllInterceptor.cpp.
+extern decltype(&DetouredCallCode) gDetouredCall;
+
+// This is just a jumper: our hooking code will thus detour the jump target
+// -- it will not detour DetouredCallJumper. We need to do this to point our
+// hooking code to the dynamic code, because our hooking API works with an
+// exported function name.
+__attribute__((naked)) __declspec(dllexport noinline) void DetouredCallJumper(
+    uintptr_t aCallee) {
+  // Ideally we would want this to be:
+  //   jmp qword ptr [rip + offset gDetouredCall]
+  // Unfortunately, it is unclear how to do that with inline assembly, so we
+  // use a zero offset and patch it before the test.
+  asm volatile("jmpq *0(%rip)");
+}
+#    endif  // !defined(MOZ_CODE_COVERAGE)
+
+#  elif defined(_M_IX86)
+constexpr uintptr_t JumpDestination = 0x7fff0000;
+
+__declspec(dllexport) __attribute__((naked)) void PushRet() {
+  asm volatile(
+      "push %0;"
+      "ret;"
+      :
+      : "i"(JumpDestination));
+}
+
+__declspec(dllexport) __attribute__((naked)) void MovEaxJump() {
+  asm volatile(
+      "mov %0, %%eax;"
+      "jmp *%%eax;"
+      :
+      : "i"(JumpDestination));
+}
+
+__declspec(dllexport) __attribute__((naked)) void Opcode83() {
+  asm volatile(
+      "xor $0x42, %eax;"
+      "cmpl $1, 0xc(%ebp);");
+}
+
+__declspec(dllexport) __attribute__((naked)) void LockPrefix() {
+  // Test an instruction with a LOCK prefix (0xf0) at a non-zero offset
+  asm volatile(
+      "push $0x7c;"
+      "lock push $0x7c;");
+}
+
+__declspec(dllexport) __attribute__((naked)) void LooksLikeLockPrefix() {
+  // This is for a regression scenario of bug 1625452, where we double-counted
+  // the offset in CountPrefixBytes.  When we count prefix bytes in front of
+  // the 2nd PUSH located at offset 2, we mistakenly started counting from
+  // the byte 0xf0 at offset 4, which is considered as LOCK, thus we try to
+  // detour the next byte 0xcc and it fails.
+  //
+  // 0: 6a7c       push 7Ch
+  // 2: 68ccf00000 push 0F0CCh
+  //
+  asm volatile(
+      "push $0x7c;"
+      "push $0x0000f0cc;");
+}
+
+__declspec(dllexport) __attribute__((naked)) void DoubleJump() {
+  asm volatile(
+      "jmp label1;"
+
+      "label2:"
+      "mov %0, %%eax;"
+      "jmp *%%eax;"
+
+      // 0x100 bytes padding to generate jmp rel32 instead of jmp rel8
+      PADDING_256_NOP
+
+      "label1:"
+      "jmp label2;"
+      :
+      : "i"(JumpDestination));
+}
+#  endif
+
+#  if !defined(_M_ARM64)
+__declspec(dllexport) __attribute__((naked)) void UnsupportedOp() {
+  asm volatile(
+      "ud2;"
+      "nop;nop;nop;nop;nop;nop;nop;nop;"
+      "nop;nop;nop;nop;nop;nop;nop;nop;");
+}
+#  endif  // !defined(_M_ARM64)
+
+#endif  // defined(__clang__)
+
+}  // extern "C"
+
+#endif  // mozilla_AssemblyPayloads_h
diff --git a/toolkit/xre/dllservices/tests/TestDllBlocklistAssumptions.cpp b/toolkit/xre/dllservices/tests/TestDllBlocklistAssumptions.cpp
new file mode 100644
index 0000000000..17c68f26dc
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/TestDllBlocklistAssumptions.cpp
@@ -0,0 +1,344 @@
+/* -*- 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/. */
+
+#include <windows.h>
+#include <tlhelp32.h>
+
+#include <stdio.h>
+
+#include "mozilla/Assertions.h"
+#include "mozilla/NativeNt.h"
+#include "mozilla/Vector.h"
+
+#include "nsWindowsDllInterceptor.h"
+
+NTSTATUS NTAPI NtMapViewOfSection(
+    HANDLE aSection, HANDLE aProcess, PVOID* aBaseAddress, ULONG_PTR aZeroBits,
+    SIZE_T aCommitSize, PLARGE_INTEGER aSectionOffset, PSIZE_T aViewSize,
+    SECTION_INHERIT aInheritDisposition, ULONG aAllocationType,
+    ULONG aProtectionFlags);
+
+using namespace mozilla;
+
+static WindowsDllInterceptor NtdllIntercept;
+
+static WindowsDllInterceptor::FuncHookType<decltype(&::NtMapViewOfSection)>
+    stub_NtMapViewOfSection;
+
+static constexpr auto kDllUsedForLoadLibraryTests = L"dbghelp.dll";
+
+class MappedViewsInfoCollector {
+ public:
+  struct MappedViewInfo {
+    PVOID BaseAddress;
+    HANDLE aSection;
+    PUBLIC_OBJECT_BASIC_INFORMATION obiSection;
+    MEMORY_BASIC_INFORMATION mbiVirtualMemory;
+  };
+
+  MappedViewsInfoCollector() = default;
+  ~MappedViewsInfoCollector() = default;
+
+  const MappedViewInfo* begin() const { return mMappedViewsInfo.begin(); }
+  const MappedViewInfo* end() const { return mMappedViewsInfo.end(); }
+
+  const MappedViewInfo* GetInfo(PVOID aBaseAddress) const {
+    for (const auto& mappedView : mMappedViewsInfo) {
+      if (mappedView.BaseAddress == aBaseAddress) {
+        return &mappedView;
+      }
+    }
+    return nullptr;
+  }
+
+  void Add(PVOID aBaseAddress, HANDLE aSection) {
+    auto existingMappedViewInfo = GetInfo(aBaseAddress);
+    if (existingMappedViewInfo) {
+      MOZ_RELEASE_ASSERT(existingMappedViewInfo->BaseAddress == aBaseAddress);
+      MOZ_RELEASE_ASSERT(existingMappedViewInfo->aSection == aSection);
+      return;
+    }
+
+    MappedViewInfo mappedViewInfo{aBaseAddress, aSection};
+    MOZ_RELEASE_ASSERT(NT_SUCCESS(::NtQueryObject(
+        aSection, ObjectBasicInformation, &mappedViewInfo.obiSection,
+        sizeof(mappedViewInfo.obiSection), nullptr)));
+    MOZ_RELEASE_ASSERT(NT_SUCCESS(::NtQueryVirtualMemory(
+        ::GetCurrentProcess(), aBaseAddress, MemoryBasicInformation,
+        &mappedViewInfo.mbiVirtualMemory,
+        sizeof(mappedViewInfo.mbiVirtualMemory), nullptr)));
+    MOZ_RELEASE_ASSERT(mMappedViewsInfo.append(std::move(mappedViewInfo)));
+  }
+
+  void Reset() { MOZ_RELEASE_ASSERT(mMappedViewsInfo.resize(0)); }
+
+ private:
+  Vector<MappedViewInfo> mMappedViewsInfo;
+};
+
+static bool sIsTestRunning = false;
+static MappedViewsInfoCollector sMappedViewsInfoCollector;
+
+NTSTATUS NTAPI patched_NtMapViewOfSection(
+    HANDLE aSection, HANDLE aProcess, PVOID* aBaseAddress, ULONG_PTR aZeroBits,
+    SIZE_T aCommitSize, PLARGE_INTEGER aSectionOffset, PSIZE_T aViewSize,
+    SECTION_INHERIT aInheritDisposition, ULONG aAllocationType,
+    ULONG aProtectionFlags) {
+  NTSTATUS result = stub_NtMapViewOfSection(
+      aSection, aProcess, aBaseAddress, aZeroBits, aCommitSize, aSectionOffset,
+      aViewSize, aInheritDisposition, aAllocationType, aProtectionFlags);
+  if (sIsTestRunning && NT_SUCCESS(result)) {
+    MOZ_RELEASE_ASSERT(aBaseAddress);
+    sMappedViewsInfoCollector.Add(*aBaseAddress, aSection);
+  }
+  return result;
+}
+
+bool InitializeTests() {
+  NtdllIntercept.Init(L"ntdll.dll");
+
+  bool success = stub_NtMapViewOfSection.Set(
+      NtdllIntercept, "NtMapViewOfSection", patched_NtMapViewOfSection);
+  if (!success) {
+    printf(
+        "TEST-UNEXPECTED-FAIL | TestDllBlocklistAssumptions | "
+        "Failed to hook NtMapViewOfSection.\n");
+    fflush(stdout);
+    return false;
+  }
+
+  printf(
+      "TEST-PASS | TestDllBlocklistAssumptions | "
+      "Successfully hooked NtMapViewOfSection.\n");
+  fflush(stdout);
+  return true;
+}
+
+bool CheckMappedViewAssumptions(const char* aTestDescription, PVOID baseAddress,
+                                bool aExpectExecutableSection,
+                                bool aExpectImageTypeMemory) {
+  auto mappedViewInfo = sMappedViewsInfoCollector.GetInfo(baseAddress);
+  if (!mappedViewInfo) {
+    printf(
+        "TEST-UNEXPECTED-FAIL | TestDllBlocklistAssumptions | "
+        "Failed to find mapped view information while testing %s.\n",
+        aTestDescription);
+    fflush(stdout);
+    return false;
+  }
+
+  MOZ_RELEASE_ASSERT(mappedViewInfo->BaseAddress == baseAddress);
+
+  if (aExpectExecutableSection !=
+      bool(mappedViewInfo->obiSection.GrantedAccess & SECTION_MAP_EXECUTE)) {
+    printf(
+        "TEST-UNEXPECTED-FAIL | TestDllBlocklistAssumptions | "
+        "Mismatch in assumptions regarding section executablity while testing "
+        "%s.\n",
+        aTestDescription);
+    fflush(stdout);
+    return false;
+  }
+
+  if (aExpectImageTypeMemory !=
+      bool(mappedViewInfo->mbiVirtualMemory.Type & MEM_IMAGE)) {
+    printf(
+        "TEST-UNEXPECTED-FAIL | TestDllBlocklistAssumptions | "
+        "Mismatch in assumptions regarding virtual memory type while testing "
+        "%s.\n",
+        aTestDescription);
+    fflush(stdout);
+    return false;
+  }
+  return true;
+}
+
+// Assumptions used to block normal DLL loads:
+//  - section handle was granted SECTION_MAP_EXECUTE access;
+//  - virtual memory is tagged as MEM_IMAGE type.
+bool TestDllLoad() {
+  sMappedViewsInfoCollector.Reset();
+
+  auto module = ::LoadLibraryW(kDllUsedForLoadLibraryTests);
+  if (!module) {
+    printf(
+        "TEST-UNEXPECTED-FAIL | TestDllBlocklistAssumptions | "
+        "Call to LoadLibraryW failed with error %lu.\n",
+        ::GetLastError());
+    fflush(stdout);
+    return false;
+  }
+
+  auto baseAddress = nt::PEHeaders::HModuleToBaseAddr<PVOID>(module);
+  bool result =
+      CheckMappedViewAssumptions("LoadLibraryW", baseAddress, true, true);
+  FreeLibrary(module);
+
+  if (result) {
+    printf(
+        "TEST-PASS | TestDllBlocklistAssumptions | "
+        "DLL loading works as expected.\n");
+    fflush(stdout);
+  }
+  return result;
+}
+
+// Assumptions used to avoid blocking DLL loads when loading as data file:
+//  - section handle was *not* granted SECTION_MAP_EXECUTE access;
+//  - virtual memory is *not* tagged as MEM_IMAGE type.
+bool TestDllLoadAsDataFile() {
+  sMappedViewsInfoCollector.Reset();
+
+  auto module = ::LoadLibraryExW(kDllUsedForLoadLibraryTests, nullptr,
+                                 LOAD_LIBRARY_AS_DATAFILE);
+  if (!module) {
+    printf(
+        "TEST-UNEXPECTED-FAIL | TestDllBlocklistAssumptions | "
+        "Call to LoadLibraryExW failed with error %lu.\n",
+        ::GetLastError());
+    fflush(stdout);
+    return false;
+  }
+
+  auto baseAddress = nt::PEHeaders::HModuleToBaseAddr<PVOID>(module);
+  bool result = CheckMappedViewAssumptions(
+      "LoadLibraryExW(LOAD_LIBRARY_AS_DATAFILE)", baseAddress, false, false);
+  FreeLibrary(module);
+
+  if (result) {
+    printf(
+        "TEST-PASS | TestDllBlocklistAssumptions | "
+        "DLL loading as data file works as expected.\n");
+    fflush(stdout);
+  }
+  return result;
+}
+
+// Assumptions used to avoid blocking DLL loads when loading as image resource:
+//  - section handle was *not* granted SECTION_MAP_EXECUTE access;
+//  - virtual memory is tagged as MEM_IMAGE type, however.
+bool TestDllLoadAsImageResource() {
+  sMappedViewsInfoCollector.Reset();
+
+  auto module = ::LoadLibraryExW(kDllUsedForLoadLibraryTests, nullptr,
+                                 LOAD_LIBRARY_AS_IMAGE_RESOURCE);
+  if (!module) {
+    printf(
+        "TEST-UNEXPECTED-FAIL | TestDllBlocklistAssumptions | "
+        "Call to LoadLibraryExW failed with error %lu.\n",
+        ::GetLastError());
+    fflush(stdout);
+    return false;
+  }
+
+  auto baseAddress = nt::PEHeaders::HModuleToBaseAddr<PVOID>(module);
+  bool result = CheckMappedViewAssumptions(
+      "LoadLibraryExW(LOAD_LIBRARY_AS_IMAGE_RESOURCE)", baseAddress, false,
+      true);
+  FreeLibrary(module);
+
+  if (result) {
+    printf(
+        "TEST-PASS | TestDllBlocklistAssumptions | "
+        "DLL loading as image resource works as expected.\n");
+    fflush(stdout);
+  }
+  return result;
+}
+
+// Assumptions used to avoid crashing when using Thread32Next (bug 1733532):
+//  - section handle was *not* granted SECTION_MAP_EXECUTE access;
+//  - virtual memory is *not* tagged as MEM_IMAGE type.
+bool TestThreadIteration() {
+  sMappedViewsInfoCollector.Reset();
+
+  HANDLE snapshot = ::CreateToolhelp32Snapshot(TH32CS_SNAPTHREAD, 0);
+  if (snapshot == INVALID_HANDLE_VALUE) {
+    printf(
+        "TEST-UNEXPECTED-FAIL | TestDllBlocklistAssumptions | "
+        "Call toCreateToolhelp32Snapshot failed with error %lu.\n",
+        ::GetLastError());
+    fflush(stdout);
+    return false;
+  }
+
+  THREADENTRY32 entry{};
+  entry.dwSize = sizeof(entry);
+  if (!::Thread32First(snapshot, &entry)) {
+    printf(
+        "TEST-UNEXPECTED-FAIL | TestDllBlocklistAssumptions | "
+        "Call to Thread32First failed with error %lu.\n",
+        ::GetLastError());
+    fflush(stdout);
+    return false;
+  }
+
+  while (::Thread32Next(snapshot, &entry)) {
+  }
+  auto error = GetLastError();
+  if (error != ERROR_NO_MORE_FILES) {
+    printf(
+        "TEST-UNEXPECTED-FAIL | TestDllBlocklistAssumptions | "
+        "Call to Thread32Next failed with unexpected error %lu.\n",
+        error);
+    fflush(stdout);
+    return false;
+  }
+
+  uint32_t count = 0;
+  for (const auto& mappedViewInfo : sMappedViewsInfoCollector) {
+    if (!CheckMappedViewAssumptions("Thread32Next", mappedViewInfo.BaseAddress,
+                                    false, false)) {
+      return false;
+    }
+    ++count;
+  }
+
+  if (!count) {
+    printf(
+        "TEST-UNEXPECTED-FAIL | TestDllBlocklistAssumptions | "
+        "Unexpectedly found no mappings after iterating threads with "
+        "Thread32Next.\n");
+    fflush(stdout);
+    return false;
+  }
+
+  printf(
+      "TEST-PASS | TestDllBlocklistAssumptions | "
+      "Iterating threads with Thread32Next works as expected.\n");
+  fflush(stdout);
+  return true;
+}
+
+extern "C" int wmain(int argc, wchar_t* argv[]) {
+  LARGE_INTEGER start;
+  QueryPerformanceCounter(&start);
+
+  sIsTestRunning = true;
+  if (InitializeTests() && TestDllLoad() && TestDllLoadAsDataFile() &&
+      TestDllLoadAsImageResource() && TestThreadIteration()) {
+    sIsTestRunning = false;
+
+    printf("TEST-PASS | TestDllBlocklistAssumptions | all checks passed\n");
+
+    LARGE_INTEGER end, freq;
+    QueryPerformanceCounter(&end);
+
+    QueryPerformanceFrequency(&freq);
+
+    LARGE_INTEGER result;
+    result.QuadPart = end.QuadPart - start.QuadPart;
+    result.QuadPart *= 1000000;
+    result.QuadPart /= freq.QuadPart;
+
+    printf("Elapsed time: %lld microseconds\n", result.QuadPart);
+
+    return 0;
+  }
+
+  sIsTestRunning = false;
+  return 1;
+}
diff --git a/toolkit/xre/dllservices/tests/TestDllInterceptor.cpp b/toolkit/xre/dllservices/tests/TestDllInterceptor.cpp
new file mode 100644
index 0000000000..2b70c9bcd4
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/TestDllInterceptor.cpp
@@ -0,0 +1,1475 @@
+/* -*- 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/. */
+
+#include <shlobj.h>
+#include <stdio.h>
+#include <commdlg.h>
+#define SECURITY_WIN32
+#include <security.h>
+#include <wininet.h>
+#include <schnlsp.h>
+#include <winternl.h>
+#include <processthreadsapi.h>
+
+#include <bcrypt.h>
+#pragma comment(lib, "bcrypt.lib")
+
+#include "AssemblyPayloads.h"
+#include "mozilla/DynamicallyLinkedFunctionPtr.h"
+#include "mozilla/UniquePtr.h"
+#include "mozilla/WindowsVersion.h"
+#include "nsWindowsDllInterceptor.h"
+#include "nsWindowsHelpers.h"
+
+NTSTATUS NTAPI NtFlushBuffersFile(HANDLE, PIO_STATUS_BLOCK);
+NTSTATUS NTAPI NtReadFile(HANDLE, HANDLE, PIO_APC_ROUTINE, PVOID,
+                          PIO_STATUS_BLOCK, PVOID, ULONG, PLARGE_INTEGER,
+                          PULONG);
+NTSTATUS NTAPI NtReadFileScatter(HANDLE, HANDLE, PIO_APC_ROUTINE, PVOID,
+                                 PIO_STATUS_BLOCK, PFILE_SEGMENT_ELEMENT, ULONG,
+                                 PLARGE_INTEGER, PULONG);
+NTSTATUS NTAPI NtWriteFile(HANDLE, HANDLE, PIO_APC_ROUTINE, PVOID,
+                           PIO_STATUS_BLOCK, PVOID, ULONG, PLARGE_INTEGER,
+                           PULONG);
+NTSTATUS NTAPI NtWriteFileGather(HANDLE, HANDLE, PIO_APC_ROUTINE, PVOID,
+                                 PIO_STATUS_BLOCK, PFILE_SEGMENT_ELEMENT, ULONG,
+                                 PLARGE_INTEGER, PULONG);
+NTSTATUS NTAPI NtQueryFullAttributesFile(POBJECT_ATTRIBUTES, PVOID);
+NTSTATUS NTAPI LdrLoadDll(PWCHAR filePath, PULONG flags,
+                          PUNICODE_STRING moduleFileName, PHANDLE handle);
+NTSTATUS NTAPI LdrUnloadDll(HMODULE);
+
+NTSTATUS NTAPI NtMapViewOfSection(
+    HANDLE aSection, HANDLE aProcess, PVOID* aBaseAddress, ULONG_PTR aZeroBits,
+    SIZE_T aCommitSize, PLARGE_INTEGER aSectionOffset, PSIZE_T aViewSize,
+    SECTION_INHERIT aInheritDisposition, ULONG aAllocationType,
+    ULONG aProtectionFlags);
+
+// These pointers are disguised as PVOID to avoid pulling in obscure headers
+PVOID NTAPI LdrResolveDelayLoadedAPI(PVOID, PVOID, PVOID, PVOID, PVOID, ULONG);
+void CALLBACK ProcessCaretEvents(HWINEVENTHOOK, DWORD, HWND, LONG, LONG, DWORD,
+                                 DWORD);
+void __fastcall BaseThreadInitThunk(BOOL aIsInitialThread, void* aStartAddress,
+                                    void* aThreadParam);
+
+BOOL WINAPI ApiSetQueryApiSetPresence(PCUNICODE_STRING, PBOOLEAN);
+
+#if (_WIN32_WINNT < 0x0602)
+BOOL WINAPI
+SetProcessMitigationPolicy(PROCESS_MITIGATION_POLICY aMitigationPolicy,
+                           PVOID aBuffer, SIZE_T aBufferLen);
+#endif  // (_WIN32_WINNT < 0x0602)
+
+#define RtlGenRandom SystemFunction036
+extern "C" BOOLEAN NTAPI RtlGenRandom(PVOID aRandomBuffer,
+                                      ULONG aRandomBufferLength);
+
+using namespace mozilla;
+
+struct payload {
+  UINT64 a;
+  UINT64 b;
+  UINT64 c;
+
+  bool operator==(const payload& other) const {
+    return (a == other.a && b == other.b && c == other.c);
+  }
+};
+
+extern "C" __declspec(dllexport) __declspec(noinline) payload
+    rotatePayload(payload p) {
+  UINT64 tmp = p.a;
+  p.a = p.b;
+  p.b = p.c;
+  p.c = tmp;
+  return p;
+}
+
+// payloadNotHooked is a target function for a test to expect a negative result.
+// We cannot use rotatePayload for that purpose because our detour cannot hook
+// a function detoured already.  Please keep this function always unhooked.
+extern "C" __declspec(dllexport) __declspec(noinline) payload
+    payloadNotHooked(payload p) {
+  // Do something different from rotatePayload to avoid ICF.
+  p.a ^= p.b;
+  p.b ^= p.c;
+  p.c ^= p.a;
+  return p;
+}
+
+// Declared as volatile to prevent optimizers from incorrectly eliding accesses
+// to it. (See bug 1769001 for a motivating example.)
+static volatile bool patched_func_called = false;
+
+static WindowsDllInterceptor::FuncHookType<decltype(&rotatePayload)>
+    orig_rotatePayload;
+
+static WindowsDllInterceptor::FuncHookType<decltype(&payloadNotHooked)>
+    orig_payloadNotHooked;
+
+static payload patched_rotatePayload(payload p) {
+  patched_func_called = true;
+  return orig_rotatePayload(p);
+}
+
+// Invoke aFunc by taking aArg's contents and using them as aFunc's arguments
+template <typename OrigFuncT, typename... Args,
+          typename ArgTuple = std::tuple<Args...>, size_t... Indices>
+decltype(auto) Apply(OrigFuncT& aFunc, ArgTuple&& aArgs,
+                     std::index_sequence<Indices...>) {
+  return std::apply(aFunc, aArgs);
+}
+
+#define DEFINE_TEST_FUNCTION(calling_convention)                               \
+  template <typename R, typename... Args, typename... TestArgs>                \
+  bool TestFunction(R(calling_convention* aFunc)(Args...), bool (*aPred)(R),   \
+                    TestArgs&&... aArgs) {                                     \
+    using ArgTuple = std::tuple<Args...>;                                      \
+    using Indices = std::index_sequence_for<Args...>;                          \
+    ArgTuple fakeArgs{std::forward<TestArgs>(aArgs)...};                       \
+    patched_func_called = false;                                               \
+    return aPred(Apply(aFunc, std::forward<ArgTuple>(fakeArgs), Indices())) && \
+           patched_func_called;                                                \
+  }                                                                            \
+                                                                               \
+  /* Specialization for functions returning void */                            \
+  template <typename PredT, typename... Args, typename... TestArgs>            \
+  bool TestFunction(void(calling_convention * aFunc)(Args...), PredT,          \
+                    TestArgs&&... aArgs) {                                     \
+    using ArgTuple = std::tuple<Args...>;                                      \
+    using Indices = std::index_sequence_for<Args...>;                          \
+    ArgTuple fakeArgs{std::forward<TestArgs>(aArgs)...};                       \
+    patched_func_called = false;                                               \
+    Apply(aFunc, std::forward<ArgTuple>(fakeArgs), Indices());                 \
+    return patched_func_called;                                                \
+  }
+
+// C++11 allows empty arguments to macros. clang works just fine. MSVC does the
+// right thing, but it also throws up warning C4003.
+#if defined(_MSC_VER) && !defined(__clang__)
+DEFINE_TEST_FUNCTION(__cdecl)
+#else
+DEFINE_TEST_FUNCTION()
+#endif
+
+#ifdef _M_IX86
+DEFINE_TEST_FUNCTION(__stdcall)
+DEFINE_TEST_FUNCTION(__fastcall)
+#endif  // _M_IX86
+
+// Test the hooked function against the supplied predicate
+template <typename OrigFuncT, typename PredicateT, typename... Args>
+bool CheckHook(OrigFuncT& aOrigFunc, const char* aDllName,
+               const char* aFuncName, PredicateT&& aPred, Args&&... aArgs) {
+  if (TestFunction(aOrigFunc, std::forward<PredicateT>(aPred),
+                   std::forward<Args>(aArgs)...)) {
+    printf(
+        "TEST-PASS | WindowsDllInterceptor | "
+        "Executed hooked function %s from %s\n",
+        aFuncName, aDllName);
+    fflush(stdout);
+    return true;
+  }
+  printf(
+      "TEST-FAILED | WindowsDllInterceptor | "
+      "Failed to execute hooked function %s from %s\n",
+      aFuncName, aDllName);
+  return false;
+}
+
+struct InterceptorFunction {
+  static const size_t EXEC_MEMBLOCK_SIZE = 64 * 1024;  // 64K
+
+  static InterceptorFunction& Create() {
+    // Make sure the executable memory is allocated
+    if (!sBlock) {
+      Init();
+    }
+    MOZ_ASSERT(sBlock);
+
+    // Make sure we aren't making more functions than we allocated room for
+    MOZ_RELEASE_ASSERT((sNumInstances + 1) * sizeof(InterceptorFunction) <=
+                       EXEC_MEMBLOCK_SIZE);
+
+    // Grab the next InterceptorFunction from executable memory
+    InterceptorFunction& ret = *reinterpret_cast<InterceptorFunction*>(
+        sBlock + (sNumInstances++ * sizeof(InterceptorFunction)));
+
+    // Set the InterceptorFunction to the code template.
+    auto funcCode = &ret[0];
+    memcpy(funcCode, sInterceptorTemplate, TemplateLength);
+
+    // Fill in the patched_func_called pointer in the template.
+    auto pfPtr =
+        reinterpret_cast<volatile bool**>(&ret[PatchedFuncCalledIndex]);
+    *pfPtr = &patched_func_called;
+    return ret;
+  }
+
+  uint8_t& operator[](size_t i) { return mFuncCode[i]; }
+
+  uint8_t* GetFunction() { return mFuncCode; }
+
+  void SetStub(uintptr_t aStub) {
+    auto pfPtr = reinterpret_cast<uintptr_t*>(&mFuncCode[StubFuncIndex]);
+    *pfPtr = aStub;
+  }
+
+ private:
+  // We intercept functions with short machine-code functions that set a boolean
+  // and run the stub that launches the original function.  Each entry in the
+  // array is the code for one of those interceptor functions.  We cannot
+  // free this memory until the test shuts down.
+  // The templates have spots for the address of patched_func_called
+  // and for the address of the stub function.  Their indices in the byte
+  // array are given as constants below and they appear as blocks of
+  // 0xff bytes in the templates.
+#if defined(_M_X64)
+  //  0: 48 b8 ff ff ff ff ff ff ff ff    movabs rax, &patched_func_called
+  //  a: c6 00 01                         mov    BYTE PTR [rax],0x1
+  //  d: 48 b8 ff ff ff ff ff ff ff ff    movabs rax, &stub_func_ptr
+  // 17: ff e0                            jmp    rax
+  static constexpr uint8_t sInterceptorTemplate[] = {
+      0x48, 0xB8, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+      0xFF, 0xC6, 0x00, 0x01, 0x48, 0xB8, 0xFF, 0xFF, 0xFF,
+      0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xE0};
+  static const size_t PatchedFuncCalledIndex = 0x2;
+  static const size_t StubFuncIndex = 0xf;
+#elif defined(_M_IX86)
+  // 0: c6 05 ff ff ff ff 01     mov    BYTE PTR &patched_func_called, 0x1
+  // 7: 68 ff ff ff ff           push   &stub_func_ptr
+  // c: c3                       ret
+  static constexpr uint8_t sInterceptorTemplate[] = {
+      0xC6, 0x05, 0xFF, 0xFF, 0xFF, 0xFF, 0x01,
+      0x68, 0xFF, 0xFF, 0xFF, 0xFF, 0xC3};
+  static const size_t PatchedFuncCalledIndex = 0x2;
+  static const size_t StubFuncIndex = 0x8;
+#elif defined(_M_ARM64)
+  //  0: 31 00 80 52    movz w17, #0x1
+  //  4: 90 00 00 58    ldr  x16, #16
+  //  8: 11 02 00 39    strb w17, [x16]
+  //  c: 90 00 00 58    ldr  x16, #16
+  // 10: 00 02 1F D6    br   x16
+  // 14: &patched_func_called
+  // 1c: &stub_func_ptr
+  static constexpr uint8_t sInterceptorTemplate[] = {
+      0x31, 0x00, 0x80, 0x52, 0x90, 0x00, 0x00, 0x58, 0x11, 0x02, 0x00, 0x39,
+      0x90, 0x00, 0x00, 0x58, 0x00, 0x02, 0x1F, 0xD6, 0xFF, 0xFF, 0xFF, 0xFF,
+      0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF};
+  static const size_t PatchedFuncCalledIndex = 0x14;
+  static const size_t StubFuncIndex = 0x1c;
+#else
+#  error "Missing template for architecture"
+#endif
+
+  static const size_t TemplateLength = sizeof(sInterceptorTemplate);
+  uint8_t mFuncCode[TemplateLength];
+
+  InterceptorFunction() = delete;
+  InterceptorFunction(const InterceptorFunction&) = delete;
+  InterceptorFunction& operator=(const InterceptorFunction&) = delete;
+
+  static void Init() {
+    MOZ_ASSERT(!sBlock);
+    sBlock = reinterpret_cast<uint8_t*>(
+        ::VirtualAlloc(nullptr, EXEC_MEMBLOCK_SIZE, MEM_RESERVE | MEM_COMMIT,
+                       PAGE_EXECUTE_READWRITE));
+  }
+
+  static uint8_t* sBlock;
+  static size_t sNumInstances;
+};
+
+uint8_t* InterceptorFunction::sBlock = nullptr;
+size_t InterceptorFunction::sNumInstances = 0;
+
+constexpr uint8_t InterceptorFunction::sInterceptorTemplate[];
+
+#ifdef _M_X64
+
+// To check that unwind information propagates from hooked functions to their
+// stubs, we need to find the real address where the detoured code lives.
+class RedirectionResolver : public interceptor::WindowsDllPatcherBase<
+                                interceptor::VMSharingPolicyShared> {
+ public:
+  uintptr_t ResolveRedirectedAddressForTest(FARPROC aFunc) {
+    bool isWin8 = IsWin8OrLater() && (!IsWin8Point1OrLater());
+
+    bool isDuplicateHandle = (reinterpret_cast<void*>(aFunc) ==
+                              reinterpret_cast<void*>(&::DuplicateHandle));
+
+    // We need to reproduce the behavior of WindowsDllInterceptor::AddDetour
+    // with respect to redirection, including the corner case for bug 1659398.
+    if (isWin8 && isDuplicateHandle) {
+      return reinterpret_cast<uintptr_t>(aFunc);
+    }
+
+    return ResolveRedirectedAddress(aFunc).GetAddress();
+  }
+};
+
+#endif  // _M_X64
+
+// Hook the function and optionally attempt calling it
+template <typename OrigFuncT, size_t N, typename PredicateT, typename... Args>
+bool TestHook(const char (&dll)[N], const char* func, PredicateT&& aPred,
+              Args&&... aArgs) {
+  auto orig_func(
+      mozilla::MakeUnique<WindowsDllInterceptor::FuncHookType<OrigFuncT>>());
+  wchar_t dllW[N];
+  std::copy(std::begin(dll), std::end(dll), std::begin(dllW));
+
+  HMODULE module = ::LoadLibraryW(dllW);
+  FARPROC funcAddr = ::GetProcAddress(module, func);
+  if (!funcAddr) {
+    printf(
+        "TEST-UNEXPECTED-FAIL | WindowsDllInterceptor | Failed to find %s from "
+        "%s\n",
+        func, dll);
+    fflush(stdout);
+    return false;
+  }
+
+#ifdef _M_X64
+
+  // Resolve what is the actual address of the code that will be detoured, as
+  // that's the code we want to compare with when we check for unwind
+  // information. Do that *before* detouring, although the address will only be
+  // used after detouring.
+  RedirectionResolver resolver;
+  auto detouredCodeAddr = resolver.ResolveRedirectedAddressForTest(funcAddr);
+
+#endif  // _M_X64
+
+  bool successful = false;
+  WindowsDllInterceptor TestIntercept;
+  TestIntercept.Init(dll);
+
+  InterceptorFunction& interceptorFunc = InterceptorFunction::Create();
+  successful = orig_func->Set(
+      TestIntercept, func,
+      reinterpret_cast<OrigFuncT>(interceptorFunc.GetFunction()));
+
+  if (successful) {
+    auto stub = reinterpret_cast<uintptr_t>(orig_func->GetStub());
+    interceptorFunc.SetStub(stub);
+    printf("TEST-PASS | WindowsDllInterceptor | Could hook %s from %s\n", func,
+           dll);
+    fflush(stdout);
+
+#ifdef _M_X64
+
+    // Check that unwind information has been added if and only if it was
+    // present for the original detoured code.
+    uintptr_t funcImageBase = 0;
+    auto funcEntry =
+        RtlLookupFunctionEntry(detouredCodeAddr, &funcImageBase, nullptr);
+    bool funcHasUnwindInfo = bool(funcEntry);
+
+    uintptr_t stubImageBase = 0;
+    auto stubEntry = RtlLookupFunctionEntry(stub, &stubImageBase, nullptr);
+    bool stubHasUnwindInfo = bool(stubEntry);
+
+    if (funcHasUnwindInfo == stubHasUnwindInfo) {
+      printf(
+          "TEST-PASS | WindowsDllInterceptor | The hook for %s from %s and "
+          "the original function are coherent with respect to unwind info: "
+          "funcHasUnwindInfo (%d) == stubHasUnwindInfo (%d).\n",
+          func, dll, funcHasUnwindInfo, stubHasUnwindInfo);
+      fflush(stdout);
+    } else {
+      printf(
+          "TEST-UNEXPECTED-FAIL | WindowsDllInterceptor | Hook for %s from %s "
+          "and the original function are not coherent with respect to unwind "
+          "info: "
+          "funcHasUnwindInfo (%d) != stubHasUnwindInfo (%d).\n",
+          func, dll, funcHasUnwindInfo, stubHasUnwindInfo);
+      fflush(stdout);
+      return false;
+    }
+
+    if (stubHasUnwindInfo) {
+      if (stub == (stubImageBase + stubEntry->BeginAddress)) {
+        printf(
+            "TEST-PASS | WindowsDllInterceptor | The hook for %s from %s has "
+            "coherent unwind info.\n",
+            func, dll);
+        fflush(stdout);
+      } else {
+        printf(
+            "TEST-UNEXPECTED-FAIL | WindowsDllInterceptor | The hook for %s "
+            " from %s has incoherent unwind info.\n",
+            func, dll);
+        fflush(stdout);
+        return false;
+      }
+    }
+
+#endif  // _M_X64
+
+    if (!aPred) {
+      printf(
+          "TEST-SKIPPED | WindowsDllInterceptor | "
+          "Will not attempt to execute patched %s.\n",
+          func);
+      fflush(stdout);
+      return true;
+    }
+
+    // Test the DLL function we just hooked.
+    return CheckHook(reinterpret_cast<OrigFuncT&>(funcAddr), dll, func,
+                     std::forward<PredicateT>(aPred),
+                     std::forward<Args>(aArgs)...);
+  } else {
+    printf(
+        "TEST-UNEXPECTED-FAIL | WindowsDllInterceptor | Failed to hook %s from "
+        "%s\n",
+        func, dll);
+    fflush(stdout);
+
+    // Print out the function's bytes so that we can easily analyze the error.
+    nsModuleHandle mod(::LoadLibraryW(dllW));
+    FARPROC funcAddr = ::GetProcAddress(mod, func);
+    if (funcAddr) {
+      const uint32_t kNumBytesToDump =
+          WindowsDllInterceptor::GetWorstCaseRequiredBytesToPatch();
+
+      printf("\tFirst %u bytes of function:\n\t", kNumBytesToDump);
+
+      auto code = reinterpret_cast<const uint8_t*>(funcAddr);
+      for (uint32_t i = 0; i < kNumBytesToDump; ++i) {
+        char suffix = (i < (kNumBytesToDump - 1)) ? ' ' : '\n';
+        printf("%02hhX%c", code[i], suffix);
+      }
+
+      fflush(stdout);
+    }
+    return false;
+  }
+}
+
+// Detour the function and optionally attempt calling it
+template <typename OrigFuncT, size_t N, typename PredicateT>
+bool TestDetour(const char (&dll)[N], const char* func, PredicateT&& aPred) {
+  auto orig_func(
+      mozilla::MakeUnique<WindowsDllInterceptor::FuncHookType<OrigFuncT>>());
+  wchar_t dllW[N];
+  std::copy(std::begin(dll), std::end(dll), std::begin(dllW));
+
+  bool successful = false;
+  WindowsDllInterceptor TestIntercept;
+  TestIntercept.Init(dll);
+
+  InterceptorFunction& interceptorFunc = InterceptorFunction::Create();
+  successful = orig_func->Set(
+      TestIntercept, func,
+      reinterpret_cast<OrigFuncT>(interceptorFunc.GetFunction()));
+
+  if (successful) {
+    interceptorFunc.SetStub(reinterpret_cast<uintptr_t>(orig_func->GetStub()));
+    printf("TEST-PASS | WindowsDllInterceptor | Could detour %s from %s\n",
+           func, dll);
+    fflush(stdout);
+    if (!aPred) {
+      printf(
+          "TEST-SKIPPED | WindowsDllInterceptor | "
+          "Will not attempt to execute patched %s.\n",
+          func);
+      fflush(stdout);
+      return true;
+    }
+
+    // Test the DLL function we just hooked.
+    HMODULE module = ::LoadLibraryW(dllW);
+    FARPROC funcAddr = ::GetProcAddress(module, func);
+    if (!funcAddr) {
+      return false;
+    }
+
+    return CheckHook(reinterpret_cast<OrigFuncT&>(funcAddr), dll, func,
+                     std::forward<PredicateT>(aPred));
+  } else {
+    printf(
+        "TEST-UNEXPECTED-FAIL | WindowsDllInterceptor | Failed to detour %s "
+        "from %s\n",
+        func, dll);
+    fflush(stdout);
+    return false;
+  }
+}
+
+// If a function pointer's type returns void*, this template converts that type
+// to return uintptr_t instead, for the purposes of predicates.
+template <typename FuncT>
+struct SubstituteForVoidPtr {
+  using Type = FuncT;
+};
+
+template <typename... Args>
+struct SubstituteForVoidPtr<void* (*)(Args...)> {
+  using Type = uintptr_t (*)(Args...);
+};
+
+#ifdef _M_IX86
+template <typename... Args>
+struct SubstituteForVoidPtr<void*(__stdcall*)(Args...)> {
+  using Type = uintptr_t(__stdcall*)(Args...);
+};
+
+template <typename... Args>
+struct SubstituteForVoidPtr<void*(__fastcall*)(Args...)> {
+  using Type = uintptr_t(__fastcall*)(Args...);
+};
+#endif  // _M_IX86
+
+// Determines the function's return type
+template <typename FuncT>
+struct ReturnType;
+
+template <typename R, typename... Args>
+struct ReturnType<R (*)(Args...)> {
+  using Type = R;
+};
+
+#ifdef _M_IX86
+template <typename R, typename... Args>
+struct ReturnType<R(__stdcall*)(Args...)> {
+  using Type = R;
+};
+
+template <typename R, typename... Args>
+struct ReturnType<R(__fastcall*)(Args...)> {
+  using Type = R;
+};
+#endif  // _M_IX86
+
+// Predicates that may be supplied during tests
+template <typename FuncT>
+struct Predicates {
+  using ArgType = typename ReturnType<FuncT>::Type;
+
+  template <ArgType CompVal>
+  static bool Equals(ArgType aValue) {
+    return CompVal == aValue;
+  }
+
+  template <ArgType CompVal>
+  static bool NotEquals(ArgType aValue) {
+    return CompVal != aValue;
+  }
+
+  template <ArgType CompVal>
+  static bool Ignore(ArgType aValue) {
+    return true;
+  }
+};
+
+// Functions that return void should be ignored, so we specialize the
+// Ignore predicate for that case. Use nullptr as the value to compare against.
+template <typename... Args>
+struct Predicates<void (*)(Args...)> {
+  template <nullptr_t DummyVal>
+  static bool Ignore() {
+    return true;
+  }
+};
+
+#ifdef _M_IX86
+template <typename... Args>
+struct Predicates<void(__stdcall*)(Args...)> {
+  template <nullptr_t DummyVal>
+  static bool Ignore() {
+    return true;
+  }
+};
+
+template <typename... Args>
+struct Predicates<void(__fastcall*)(Args...)> {
+  template <nullptr_t DummyVal>
+  static bool Ignore() {
+    return true;
+  }
+};
+#endif  // _M_IX86
+
+// The standard test. Hook |func|, and then try executing it with all zero
+// arguments, using |pred| and |comp| to determine whether the call successfully
+// executed. In general, you want set pred and comp such that they return true
+// when the function is returning whatever value is expected with all-zero
+// arguments.
+//
+// Note: When |func| returns void, you must supply |Ignore| and |nullptr| as the
+// |pred| and |comp| arguments, respectively.
+#define TEST_HOOK_HELPER(dll, func, pred, comp) \
+  TestHook<decltype(&func)>(dll, #func,         \
+                            &Predicates<decltype(&func)>::pred<comp>)
+
+#define TEST_HOOK(dll, func, pred, comp) TEST_HOOK_HELPER(dll, func, pred, comp)
+
+// We need to special-case functions that return INVALID_HANDLE_VALUE
+// (ie, CreateFile). Our template machinery for comparing values doesn't work
+// with integer constants passed as pointers (well, it works on MSVC, but not
+// clang, because that is not standard-compliant).
+#define TEST_HOOK_FOR_INVALID_HANDLE_VALUE(dll, func)                   \
+  TestHook<SubstituteForVoidPtr<decltype(&func)>::Type>(                \
+      dll, #func,                                                       \
+      &Predicates<SubstituteForVoidPtr<decltype(&func)>::Type>::Equals< \
+          uintptr_t(-1)>)
+
+// This variant allows you to explicitly supply arguments to the hooked function
+// during testing. You want to provide arguments that produce the conditions
+// that induce the function to return a value that is accepted by your
+// predicate.
+#define TEST_HOOK_PARAMS(dll, func, pred, comp, ...) \
+  TestHook<decltype(&func)>(                         \
+      dll, #func, &Predicates<decltype(&func)>::pred<comp>, __VA_ARGS__)
+
+// This is for cases when we want to hook |func|, but it is unsafe to attempt
+// to execute the function in the context of a test.
+#define TEST_HOOK_SKIP_EXEC(dll, func)                                        \
+  TestHook<decltype(&func)>(                                                  \
+      dll, #func,                                                             \
+      reinterpret_cast<bool (*)(typename ReturnType<decltype(&func)>::Type)>( \
+          NULL))
+
+// The following three variants are identical to the previous macros,
+// however the forcibly use a Detour on 32-bit Windows. On 64-bit Windows,
+// these macros are identical to their TEST_HOOK variants.
+#define TEST_DETOUR(dll, func, pred, comp) \
+  TestDetour<decltype(&func)>(dll, #func,  \
+                              &Predicates<decltype(&func)>::pred<comp>)
+
+#define TEST_DETOUR_PARAMS(dll, func, pred, comp, ...) \
+  TestDetour<decltype(&func)>(                         \
+      dll, #func, &Predicates<decltype(&func)>::pred<comp>, __VA_ARGS__)
+
+#define TEST_DETOUR_SKIP_EXEC(dll, func)                                      \
+  TestDetour<decltype(&func)>(                                                \
+      dll, #func,                                                             \
+      reinterpret_cast<bool (*)(typename ReturnType<decltype(&func)>::Type)>( \
+          NULL))
+
+template <typename OrigFuncT, size_t N, typename PredicateT, typename... Args>
+bool MaybeTestHook(const bool cond, const char (&dll)[N], const char* func,
+                   PredicateT&& aPred, Args&&... aArgs) {
+  if (!cond) {
+    printf(
+        "TEST-SKIPPED | WindowsDllInterceptor | Skipped hook test for %s from "
+        "%s\n",
+        func, dll);
+    fflush(stdout);
+    return true;
+  }
+
+  return TestHook<OrigFuncT>(dll, func, std::forward<PredicateT>(aPred),
+                             std::forward<Args>(aArgs)...);
+}
+
+// Like TEST_HOOK, but the test is only executed when cond is true.
+#define MAYBE_TEST_HOOK(cond, dll, func, pred, comp) \
+  MaybeTestHook<decltype(&func)>(cond, dll, #func,   \
+                                 &Predicates<decltype(&func)>::pred<comp>)
+
+#define MAYBE_TEST_HOOK_PARAMS(cond, dll, func, pred, comp, ...) \
+  MaybeTestHook<decltype(&func)>(                                \
+      cond, dll, #func, &Predicates<decltype(&func)>::pred<comp>, __VA_ARGS__)
+
+#define MAYBE_TEST_HOOK_SKIP_EXEC(cond, dll, func)                            \
+  MaybeTestHook<decltype(&func)>(                                             \
+      cond, dll, #func,                                                       \
+      reinterpret_cast<bool (*)(typename ReturnType<decltype(&func)>::Type)>( \
+          NULL))
+
+bool ShouldTestTipTsf() {
+  if (!IsWin8OrLater()) {
+    return false;
+  }
+
+  mozilla::DynamicallyLinkedFunctionPtr<decltype(&SHGetKnownFolderPath)>
+      pSHGetKnownFolderPath(L"shell32.dll", "SHGetKnownFolderPath");
+  if (!pSHGetKnownFolderPath) {
+    return false;
+  }
+
+  PWSTR commonFilesPath = nullptr;
+  if (FAILED(pSHGetKnownFolderPath(FOLDERID_ProgramFilesCommon, 0, nullptr,
+                                   &commonFilesPath))) {
+    return false;
+  }
+
+  wchar_t fullPath[MAX_PATH + 1] = {};
+  wcscpy(fullPath, commonFilesPath);
+  wcscat(fullPath, L"\\Microsoft Shared\\Ink\\tiptsf.dll");
+  CoTaskMemFree(commonFilesPath);
+
+  if (!LoadLibraryW(fullPath)) {
+    return false;
+  }
+
+  // Leak the module so that it's loaded for the interceptor test
+  return true;
+}
+
+static const wchar_t gEmptyUnicodeStringLiteral[] = L"";
+static UNICODE_STRING gEmptyUnicodeString;
+static BOOLEAN gIsPresent;
+
+bool HasApiSetQueryApiSetPresence() {
+  mozilla::DynamicallyLinkedFunctionPtr<decltype(&ApiSetQueryApiSetPresence)>
+      func(L"Api-ms-win-core-apiquery-l1-1-0.dll", "ApiSetQueryApiSetPresence");
+  if (!func) {
+    return false;
+  }
+
+  // Prepare gEmptyUnicodeString for the test
+  ::RtlInitUnicodeString(&gEmptyUnicodeString, gEmptyUnicodeStringLiteral);
+
+  return true;
+}
+
+// Set this to true to test function unhooking (currently broken).
+const bool ShouldTestUnhookFunction = false;
+
+#if defined(_M_X64) || defined(_M_ARM64)
+
+// Use VMSharingPolicyUnique for the ShortInterceptor, as it needs to
+// reserve its trampoline memory in a special location.
+using ShortInterceptor = mozilla::interceptor::WindowsDllInterceptor<
+    mozilla::interceptor::VMSharingPolicyUnique<
+        mozilla::interceptor::MMPolicyInProcess>>;
+
+static ShortInterceptor::FuncHookType<decltype(&::NtMapViewOfSection)>
+    orig_NtMapViewOfSection;
+
+#endif  // defined(_M_X64) || defined(_M_ARM64)
+
+bool TestShortDetour() {
+#if defined(_M_X64) || defined(_M_ARM64)
+  auto pNtMapViewOfSection = reinterpret_cast<decltype(&::NtMapViewOfSection)>(
+      ::GetProcAddress(::GetModuleHandleW(L"ntdll.dll"), "NtMapViewOfSection"));
+  if (!pNtMapViewOfSection) {
+    printf(
+        "TEST-FAILED | WindowsDllInterceptor | "
+        "Failed to resolve ntdll!NtMapViewOfSection\n");
+    fflush(stdout);
+    return false;
+  }
+
+  {  // Scope for shortInterceptor
+    ShortInterceptor shortInterceptor;
+    shortInterceptor.TestOnlyDetourInit(
+        L"ntdll.dll",
+        mozilla::interceptor::DetourFlags::eTestOnlyForceShortPatch);
+
+    InterceptorFunction& interceptorFunc = InterceptorFunction::Create();
+    if (!orig_NtMapViewOfSection.SetDetour(
+            shortInterceptor, "NtMapViewOfSection",
+            reinterpret_cast<decltype(&::NtMapViewOfSection)>(
+                interceptorFunc.GetFunction()))) {
+      printf(
+          "TEST-FAILED | WindowsDllInterceptor | "
+          "Failed to hook ntdll!NtMapViewOfSection via 10-byte patch\n");
+      fflush(stdout);
+      return false;
+    }
+
+    interceptorFunc.SetStub(
+        reinterpret_cast<uintptr_t>(orig_NtMapViewOfSection.GetStub()));
+
+    auto pred =
+        &Predicates<decltype(&::NtMapViewOfSection)>::Ignore<((NTSTATUS)0)>;
+
+    if (!CheckHook(pNtMapViewOfSection, "ntdll.dll", "NtMapViewOfSection",
+                   pred)) {
+      // CheckHook has already printed the error message for us
+      return false;
+    }
+  }
+
+  // Now ensure that our hook cleanup worked
+  if (ShouldTestUnhookFunction) {
+    NTSTATUS status =
+        pNtMapViewOfSection(nullptr, nullptr, nullptr, 0, 0, nullptr, nullptr,
+                            ((SECTION_INHERIT)0), 0, 0);
+    if (NT_SUCCESS(status)) {
+      printf(
+          "TEST-FAILED | WindowsDllInterceptor | "
+          "Unexpected successful call to ntdll!NtMapViewOfSection after "
+          "removing short-patched hook\n");
+      fflush(stdout);
+      return false;
+    }
+
+    printf(
+        "TEST-PASS | WindowsDllInterceptor | "
+        "Successfully unhooked ntdll!NtMapViewOfSection via short patch\n");
+    fflush(stdout);
+  }
+
+  return true;
+#else
+  return true;
+#endif
+}
+
+constexpr uintptr_t NoStubAddressCheck = 0;
+constexpr uintptr_t ExpectedFail = 1;
+struct TestCase {
+  const char* mFunctionName;
+  uintptr_t mExpectedStub;
+  bool mPatchedOnce;
+  explicit TestCase(const char* aFunctionName, uintptr_t aExpectedStub)
+      : mFunctionName(aFunctionName),
+        mExpectedStub(aExpectedStub),
+        mPatchedOnce(false) {}
+} g_AssemblyTestCases[] = {
+#if defined(__clang__)
+// We disable these testcases because the code coverage instrumentation injects
+// code in a way that WindowsDllInterceptor doesn't understand.
+#  ifndef MOZ_CODE_COVERAGE
+#    if defined(_M_X64)
+    // Since we have PatchIfTargetIsRecognizedTrampoline for x64, we expect the
+    // original jump destination is returned as a stub.
+    TestCase("MovPushRet", JumpDestination),
+    TestCase("MovRaxJump", JumpDestination),
+    TestCase("DoubleJump", JumpDestination),
+
+    // Passing NoStubAddressCheck as the following testcases return
+    // a trampoline address instead of the original destination.
+    TestCase("NearJump", NoStubAddressCheck),
+    TestCase("OpcodeFF", NoStubAddressCheck),
+    TestCase("IndirectCall", NoStubAddressCheck),
+    TestCase("MovImm64", NoStubAddressCheck),
+#    elif defined(_M_IX86)
+    // Skip the stub address check as we always generate a trampoline for x86.
+    TestCase("PushRet", NoStubAddressCheck),
+    TestCase("MovEaxJump", NoStubAddressCheck),
+    TestCase("DoubleJump", NoStubAddressCheck),
+    TestCase("Opcode83", NoStubAddressCheck),
+    TestCase("LockPrefix", NoStubAddressCheck),
+    TestCase("LooksLikeLockPrefix", NoStubAddressCheck),
+#    endif
+#    if !defined(DEBUG)
+    // Skip on Debug build because it hits MOZ_ASSERT_UNREACHABLE.
+    TestCase("UnsupportedOp", ExpectedFail),
+#    endif  // !defined(DEBUG)
+#  endif    // MOZ_CODE_COVERAGE
+#endif      // defined(__clang__)
+};
+
+template <typename InterceptorType>
+bool TestAssemblyFunctions() {
+  static const auto patchedFunction = []() { patched_func_called = true; };
+
+  InterceptorType interceptor;
+  interceptor.Init("TestDllInterceptor.exe");
+
+  for (auto& testCase : g_AssemblyTestCases) {
+    if (testCase.mExpectedStub == NoStubAddressCheck && testCase.mPatchedOnce) {
+      // For the testcases with NoStubAddressCheck, we revert a hook by
+      // jumping into the original stub, which is not detourable again.
+      continue;
+    }
+
+    typename InterceptorType::template FuncHookType<void (*)()> hook;
+    bool result =
+        hook.Set(interceptor, testCase.mFunctionName, patchedFunction);
+    if (testCase.mExpectedStub == ExpectedFail) {
+      if (result) {
+        printf(
+            "TEST-FAILED | WindowsDllInterceptor | "
+            "Unexpectedly succeeded to detour %s.\n",
+            testCase.mFunctionName);
+        return false;
+      }
+#if defined(NIGHTLY_BUILD)
+      const Maybe<DetourError>& maybeError = interceptor.GetLastDetourError();
+      if (maybeError.isNothing()) {
+        printf(
+            "TEST-FAILED | WindowsDllInterceptor | "
+            "DetourError was not set on detour error.\n");
+        return false;
+      }
+      if (maybeError.ref().mErrorCode !=
+          DetourResultCode::DETOUR_PATCHER_CREATE_TRAMPOLINE_ERROR) {
+        printf(
+            "TEST-FAILED | WindowsDllInterceptor | "
+            "A wrong detour errorcode was set on detour error.\n");
+        return false;
+      }
+#endif  // defined(NIGHTLY_BUILD)
+      printf("TEST-PASS | WindowsDllInterceptor | %s\n",
+             testCase.mFunctionName);
+      continue;
+    }
+
+    if (!result) {
+      printf(
+          "TEST-FAILED | WindowsDllInterceptor | "
+          "Failed to detour %s.\n",
+          testCase.mFunctionName);
+      return false;
+    }
+
+    testCase.mPatchedOnce = true;
+
+    const auto actualStub = reinterpret_cast<uintptr_t>(hook.GetStub());
+    if (testCase.mExpectedStub != NoStubAddressCheck &&
+        actualStub != testCase.mExpectedStub) {
+      printf(
+          "TEST-FAILED | WindowsDllInterceptor | "
+          "Wrong stub was backed up for %s: %zx\n",
+          testCase.mFunctionName, actualStub);
+      return false;
+    }
+
+    patched_func_called = false;
+
+    auto originalFunction = reinterpret_cast<void (*)()>(
+        GetProcAddress(GetModuleHandleW(nullptr), testCase.mFunctionName));
+    originalFunction();
+
+    if (!patched_func_called) {
+      printf(
+          "TEST-FAILED | WindowsDllInterceptor | "
+          "Hook from %s was not called\n",
+          testCase.mFunctionName);
+      return false;
+    }
+
+    printf("TEST-PASS | WindowsDllInterceptor | %s\n", testCase.mFunctionName);
+  }
+
+  return true;
+}
+
+#if defined(_M_X64) && !defined(MOZ_CODE_COVERAGE)
+// We want to test hooking and unhooking with unwind information, so we need:
+//  - a VMSharingPolicy such that ShouldUnhookUponDestruction() is true and
+//    Items() is implemented;
+//  - a MMPolicy such that ShouldUnhookUponDestruction() is true and
+//    kSupportsUnwindInfo is true.
+using DetouredCallInterceptor = mozilla::interceptor::WindowsDllInterceptor<
+    mozilla::interceptor::VMSharingPolicyUnique<
+        mozilla::interceptor::MMPolicyInProcess>>;
+
+struct DetouredCallChunk {
+  alignas(uint32_t) RUNTIME_FUNCTION functionTable[1];
+  alignas(uint32_t) uint8_t unwindInfo[sizeof(gDetouredCallUnwindInfo)];
+  uint8_t code[gDetouredCallCodeSize];
+};
+
+// Unfortunately using RtlAddFunctionTable for static code that lives within
+// a module doesn't seem to work. Presumably it conflicts with the static
+// function tables. So we recreate gDetouredCall as dynamic code to be able to
+// associate it with unwind information.
+decltype(&DetouredCallCode) gDetouredCall =
+    []() -> decltype(&DetouredCallCode) {
+  // We first adjust the detoured call jumper from:
+  //   ff 25 00 00 00 00    jmp qword ptr [rip + 0]
+  // to:
+  //   ff 25 XX XX XX XX    jmp qword ptr [rip + offset gDetouredCall]
+  uint8_t bytes[6]{0xff, 0x25, 0, 0, 0, 0};
+  if (0 != memcmp(bytes, reinterpret_cast<void*>(DetouredCallJumper),
+                  sizeof bytes)) {
+    return nullptr;
+  }
+
+  DWORD oldProtect{};
+  if (!VirtualProtect(reinterpret_cast<void*>(DetouredCallJumper), sizeof bytes,
+                      PAGE_READWRITE, &oldProtect)) {
+    return nullptr;
+  }
+
+  *reinterpret_cast<uint32_t*>(&bytes[2]) = static_cast<uint32_t>(
+      reinterpret_cast<uintptr_t>(&gDetouredCall) -
+      (reinterpret_cast<uintptr_t>(DetouredCallJumper) + sizeof bytes));
+  memcpy(reinterpret_cast<void*>(DetouredCallJumper), bytes, sizeof bytes);
+
+  if (!VirtualProtect(reinterpret_cast<void*>(DetouredCallJumper), sizeof bytes,
+                      oldProtect, &oldProtect)) {
+    return nullptr;
+  }
+
+  auto detouredCallChunk = reinterpret_cast<DetouredCallChunk*>(
+      VirtualAlloc(nullptr, sizeof(DetouredCallChunk), MEM_RESERVE | MEM_COMMIT,
+                   PAGE_READWRITE));
+  if (!detouredCallChunk) {
+    return nullptr;
+  }
+
+  detouredCallChunk->functionTable[0].BeginAddress =
+      offsetof(DetouredCallChunk, code);
+  detouredCallChunk->functionTable[0].EndAddress =
+      offsetof(DetouredCallChunk, code) + gDetouredCallCodeSize;
+  detouredCallChunk->functionTable[0].UnwindData =
+      offsetof(DetouredCallChunk, unwindInfo);
+  memcpy(reinterpret_cast<void*>(&detouredCallChunk->unwindInfo),
+         reinterpret_cast<void*>(gDetouredCallUnwindInfo),
+         sizeof(detouredCallChunk->unwindInfo));
+  memcpy(reinterpret_cast<void*>(&detouredCallChunk->code[0]),
+         reinterpret_cast<void*>(DetouredCallCode),
+         sizeof(detouredCallChunk->code));
+
+  if (!VirtualProtect(reinterpret_cast<void*>(detouredCallChunk),
+                      sizeof(DetouredCallChunk), PAGE_EXECUTE_READ,
+                      &oldProtect)) {
+    VirtualFree(detouredCallChunk, 0, MEM_RELEASE);
+    return nullptr;
+  }
+
+  if (!RtlAddFunctionTable(detouredCallChunk->functionTable, 1,
+                           reinterpret_cast<uintptr_t>(detouredCallChunk))) {
+    VirtualFree(detouredCallChunk, 0, MEM_RELEASE);
+    return nullptr;
+  }
+
+  return reinterpret_cast<decltype(&DetouredCallCode)>(detouredCallChunk->code);
+}();
+
+// We use our own variable instead of patched_func_called because the callee of
+// gDetouredCall could end up calling other, already hooked functions could
+// change patched_func_called.
+static volatile bool sCalledPatchedDetouredCall = false;
+static volatile bool sCalledDetouredCallCallee = false;
+static volatile bool sCouldUnwindFromDetouredCallCallee = false;
+void DetouredCallCallee() {
+  sCalledDetouredCallCallee = true;
+
+  // Check that we can fully unwind the stack
+  CONTEXT contextRecord{};
+  RtlCaptureContext(&contextRecord);
+  if (!contextRecord.Rip) {
+    printf(
+        "TEST-UNEXPECTED-FAIL | WindowsDllInterceptor | "
+        "DetouredCallCallee was unable to get an initial context to work "
+        "with\n");
+    fflush(stdout);
+    return;
+  }
+  while (contextRecord.Rip) {
+    DWORD64 imageBase = 0;
+    auto FunctionEntry =
+        RtlLookupFunctionEntry(contextRecord.Rip, &imageBase, nullptr);
+    if (!FunctionEntry) {
+      printf(
+          "TEST-UNEXPECTED-FAIL | WindowsDllInterceptor | "
+          "DetouredCallCallee was unable to get unwind info for ControlPc=%p\n",
+          reinterpret_cast<void*>(contextRecord.Rip));
+      fflush(stdout);
+      return;
+    }
+    printf(
+        "TEST-PASS | WindowsDllInterceptor | "
+        "DetouredCallCallee was able to get unwind info for ControlPc=%p\n",
+        reinterpret_cast<void*>(contextRecord.Rip));
+    fflush(stdout);
+    void* handlerData = nullptr;
+    DWORD64 establisherFrame = 0;
+    RtlVirtualUnwind(UNW_FLAG_NHANDLER, imageBase, contextRecord.Rip,
+                     FunctionEntry, &contextRecord, &handlerData,
+                     &establisherFrame, nullptr);
+  }
+  sCouldUnwindFromDetouredCallCallee = true;
+}
+
+static DetouredCallInterceptor::FuncHookType<decltype(&DetouredCallCode)>
+    orig_DetouredCall;
+
+static void patched_DetouredCall(uintptr_t aCallee) {
+  sCalledPatchedDetouredCall = true;
+  return orig_DetouredCall(aCallee);
+}
+
+bool TestCallingDetouredCall(const char* aTestDescription,
+                             bool aExpectCalledPatchedDetouredCall) {
+  sCalledPatchedDetouredCall = false;
+  sCalledDetouredCallCallee = false;
+  sCouldUnwindFromDetouredCallCallee = false;
+  DetouredCallJumper(reinterpret_cast<uintptr_t>(DetouredCallCallee));
+
+  if (aExpectCalledPatchedDetouredCall != sCalledPatchedDetouredCall) {
+    printf(
+        "TEST-UNEXPECTED-FAIL | WindowsDllInterceptor | "
+        "%s: expectCalledPatchedDetouredCall (%d) differs from "
+        "sCalledPatchedDetouredCall (%d)\n",
+        aTestDescription, aExpectCalledPatchedDetouredCall,
+        sCalledPatchedDetouredCall);
+    fflush(stdout);
+    return false;
+  }
+
+  printf(
+      "TEST-PASS | WindowsDllInterceptor | "
+      "%s: expectCalledPatchedDetouredCall (%d) matches with "
+      "sCalledPatchedDetouredCall (%d)\n",
+      aTestDescription, aExpectCalledPatchedDetouredCall,
+      sCalledPatchedDetouredCall);
+  fflush(stdout);
+
+  if (!sCalledDetouredCallCallee) {
+    printf(
+        "TEST-UNEXPECTED-FAIL | WindowsDllInterceptor | "
+        "%s: gDetouredCall failed to call its callee\n",
+        aTestDescription);
+    fflush(stdout);
+    return false;
+  }
+
+  printf(
+      "TEST-PASS | WindowsDllInterceptor | "
+      "%s: gDetouredCall successfully called its callee\n",
+      aTestDescription);
+  fflush(stdout);
+
+  if (!sCouldUnwindFromDetouredCallCallee) {
+    printf(
+        "TEST-UNEXPECTED-FAIL | WindowsDllInterceptor | "
+        "%s: the callee of gDetouredCall failed to unwind\n",
+        aTestDescription);
+    fflush(stdout);
+    return false;
+  }
+
+  printf(
+      "TEST-PASS | WindowsDllInterceptor | "
+      "%s: the callee of gDetouredCall successfully unwinded\n",
+      aTestDescription);
+  fflush(stdout);
+  return true;
+}
+
+// Test that detouring a call preserves unwind information (bug 1798787).
+bool TestDetouredCallUnwindInfo() {
+  if (!gDetouredCall) {
+    printf(
+        "TEST-UNEXPECTED-FAIL | WindowsDllInterceptor | "
+        "Failed to generate dynamic gDetouredCall code\n");
+    fflush(stdout);
+    return false;
+  }
+
+  uintptr_t imageBase = 0;
+  if (!RtlLookupFunctionEntry(reinterpret_cast<uintptr_t>(gDetouredCall),
+                              &imageBase, nullptr)) {
+    printf(
+        "TEST-UNEXPECTED-FAIL | WindowsDllInterceptor | "
+        "Failed to find unwind information for dynamic gDetouredCall code\n");
+    fflush(stdout);
+    return false;
+  }
+
+  // We first double check that we manage to unwind when we *do not* detour
+  if (!TestCallingDetouredCall("Before hooking", false)) {
+    return false;
+  }
+
+  uintptr_t StubAddress = 0;
+
+  // The real test starts here: let's detour and check if we can still unwind
+  {
+    DetouredCallInterceptor ExeIntercept;
+    ExeIntercept.Init("TestDllInterceptor.exe");
+    if (!orig_DetouredCall.Set(ExeIntercept, "DetouredCallJumper",
+                               &patched_DetouredCall)) {
+      printf(
+          "TEST-UNEXPECTED-FAIL | WindowsDllInterceptor | "
+          "Failed to hook the detoured call jumper.\n");
+      fflush(stdout);
+      return false;
+    }
+
+    printf(
+        "TEST-PASS | WindowsDllInterceptor | "
+        "Successfully hooked the detoured call jumper.\n");
+    fflush(stdout);
+
+    StubAddress = reinterpret_cast<uintptr_t>(orig_DetouredCall.GetStub());
+    if (!RtlLookupFunctionEntry(StubAddress, &imageBase, nullptr)) {
+      printf(
+          "TEST-UNEXPECTED-FAIL | WindowsDllInterceptor | "
+          "Failed to find unwind information for detoured code of "
+          "gDetouredCall\n");
+      fflush(stdout);
+      return false;
+    }
+
+    TestCallingDetouredCall("After hooking", true);
+  }
+
+  // Check that we can still unwind after clearing the hook.
+  return TestCallingDetouredCall("After unhooking", false);
+}
+#endif  // defined(_M_X64) && !defined(MOZ_CODE_COVERAGE)
+
+bool TestDynamicCodePolicy() {
+  if (!IsWin8Point1OrLater()) {
+    // Skip if a platform does not support this policy.
+    return true;
+  }
+
+  PROCESS_MITIGATION_DYNAMIC_CODE_POLICY policy = {};
+  policy.ProhibitDynamicCode = true;
+
+  mozilla::DynamicallyLinkedFunctionPtr<decltype(&SetProcessMitigationPolicy)>
+      pSetProcessMitigationPolicy(L"kernel32.dll",
+                                  "SetProcessMitigationPolicy");
+  if (!pSetProcessMitigationPolicy) {
+    printf(
+        "TEST-UNEXPECTED-FAIL | WindowsDllInterceptor | "
+        "SetProcessMitigationPolicy does not exist.\n");
+    fflush(stdout);
+    return false;
+  }
+
+  if (!pSetProcessMitigationPolicy(ProcessDynamicCodePolicy, &policy,
+                                   sizeof(policy))) {
+    printf(
+        "TEST-UNEXPECTED-FAIL | WindowsDllInterceptor | "
+        "Fail to enable ProcessDynamicCodePolicy.\n");
+    fflush(stdout);
+    return false;
+  }
+
+  WindowsDllInterceptor ExeIntercept;
+  ExeIntercept.Init("TestDllInterceptor.exe");
+
+  // Make sure we fail to hook a function if ProcessDynamicCodePolicy is on
+  // because we cannot create an executable trampoline region.
+  if (orig_payloadNotHooked.Set(ExeIntercept, "payloadNotHooked",
+                                &patched_rotatePayload)) {
+    printf(
+        "TEST-UNEXPECTED-FAIL | WindowsDllInterceptor | "
+        "ProcessDynamicCodePolicy is not working.\n");
+    fflush(stdout);
+    return false;
+  }
+
+  printf(
+      "TEST-PASS | WindowsDllInterceptor | "
+      "Successfully passed TestDynamicCodePolicy.\n");
+  fflush(stdout);
+  return true;
+}
+
+extern "C" int wmain(int argc, wchar_t* argv[]) {
+  LARGE_INTEGER start;
+  QueryPerformanceCounter(&start);
+
+  // We disable this part of the test because the code coverage instrumentation
+  // injects code in rotatePayload in a way that WindowsDllInterceptor doesn't
+  // understand.
+#ifndef MOZ_CODE_COVERAGE
+  payload initial = {0x12345678, 0xfc4e9d31, 0x87654321};
+  payload p0, p1;
+  ZeroMemory(&p0, sizeof(p0));
+  ZeroMemory(&p1, sizeof(p1));
+
+  p0 = rotatePayload(initial);
+
+  {
+    WindowsDllInterceptor ExeIntercept;
+    ExeIntercept.Init("TestDllInterceptor.exe");
+    if (orig_rotatePayload.Set(ExeIntercept, "rotatePayload",
+                               &patched_rotatePayload)) {
+      printf("TEST-PASS | WindowsDllInterceptor | Hook added\n");
+      fflush(stdout);
+    } else {
+      printf(
+          "TEST-UNEXPECTED-FAIL | WindowsDllInterceptor | Failed to add "
+          "hook\n");
+      fflush(stdout);
+      return 1;
+    }
+
+    p1 = rotatePayload(initial);
+
+    if (patched_func_called) {
+      printf("TEST-PASS | WindowsDllInterceptor | Hook called\n");
+      fflush(stdout);
+    } else {
+      printf(
+          "TEST-UNEXPECTED-FAIL | WindowsDllInterceptor | Hook was not "
+          "called\n");
+      fflush(stdout);
+      return 1;
+    }
+
+    if (p0 == p1) {
+      printf("TEST-PASS | WindowsDllInterceptor | Hook works properly\n");
+      fflush(stdout);
+    } else {
+      printf(
+          "TEST-UNEXPECTED-FAIL | WindowsDllInterceptor | Hook didn't return "
+          "the right information\n");
+      fflush(stdout);
+      return 1;
+    }
+  }
+
+  patched_func_called = false;
+  ZeroMemory(&p1, sizeof(p1));
+
+  p1 = rotatePayload(initial);
+
+  if (ShouldTestUnhookFunction != patched_func_called) {
+    printf(
+        "TEST-PASS | WindowsDllInterceptor | Hook was %scalled after "
+        "unregistration\n",
+        ShouldTestUnhookFunction ? "not " : "");
+    fflush(stdout);
+  } else {
+    printf(
+        "TEST-UNEXPECTED-FAIL | WindowsDllInterceptor | Hook was %scalled "
+        "after unregistration\n",
+        ShouldTestUnhookFunction ? "" : "not ");
+    fflush(stdout);
+    return 1;
+  }
+
+  if (p0 == p1) {
+    printf(
+        "TEST-PASS | WindowsDllInterceptor | Original function worked "
+        "properly\n");
+    fflush(stdout);
+  } else {
+    printf(
+        "TEST-UNEXPECTED-FAIL | WindowsDllInterceptor | Original function "
+        "didn't return the right information\n");
+    fflush(stdout);
+    return 1;
+  }
+#endif
+
+  CredHandle credHandle;
+  memset(&credHandle, 0, sizeof(CredHandle));
+  OBJECT_ATTRIBUTES attributes = {};
+
+  // NB: These tests should be ordered such that lower-level APIs are tested
+  // before higher-level APIs.
+  if (TestShortDetour() &&
+  // Run <ShortInterceptor> first because <WindowsDllInterceptor>
+  // does not clean up hooks.
+#if defined(_M_X64)
+      TestAssemblyFunctions<ShortInterceptor>() &&
+#endif
+      TestAssemblyFunctions<WindowsDllInterceptor>() &&
+#ifdef _M_IX86
+      // We keep this test to hook complex code on x86. (Bug 850957)
+      TEST_HOOK("ntdll.dll", NtFlushBuffersFile, NotEquals, 0) &&
+#endif
+      TEST_HOOK("ntdll.dll", NtCreateFile, NotEquals, 0) &&
+      TEST_HOOK("ntdll.dll", NtReadFile, NotEquals, 0) &&
+      TEST_HOOK("ntdll.dll", NtReadFileScatter, NotEquals, 0) &&
+      TEST_HOOK("ntdll.dll", NtWriteFile, NotEquals, 0) &&
+      TEST_HOOK("ntdll.dll", NtWriteFileGather, NotEquals, 0) &&
+      TEST_HOOK_PARAMS("ntdll.dll", NtQueryFullAttributesFile, NotEquals, 0,
+                       &attributes, nullptr) &&
+      TEST_DETOUR_SKIP_EXEC("ntdll.dll", LdrLoadDll) &&
+      TEST_HOOK("ntdll.dll", LdrUnloadDll, NotEquals, 0) &&
+      MAYBE_TEST_HOOK_SKIP_EXEC(IsWin8OrLater(), "ntdll.dll",
+                                LdrResolveDelayLoadedAPI) &&
+      MAYBE_TEST_HOOK_PARAMS(HasApiSetQueryApiSetPresence(),
+                             "Api-ms-win-core-apiquery-l1-1-0.dll",
+                             ApiSetQueryApiSetPresence, Equals, FALSE,
+                             &gEmptyUnicodeString, &gIsPresent) &&
+      TEST_HOOK("kernelbase.dll", QueryDosDeviceW, Equals, 0) &&
+      TEST_HOOK("kernel32.dll", GetFileAttributesW, Equals,
+                INVALID_FILE_ATTRIBUTES) &&
+#if !defined(_M_ARM64)
+#  ifndef MOZ_ASAN
+      // Bug 733892: toolkit/crashreporter/nsExceptionHandler.cpp
+      // This fails on ASan because the ASan runtime already hooked this
+      // function
+      TEST_HOOK("kernel32.dll", SetUnhandledExceptionFilter, Ignore, nullptr) &&
+#  endif
+#endif  // !defined(_M_ARM64)
+#ifdef _M_IX86
+      TEST_HOOK_FOR_INVALID_HANDLE_VALUE("kernel32.dll", CreateFileW) &&
+#endif
+#if !defined(_M_ARM64)
+      TEST_HOOK_FOR_INVALID_HANDLE_VALUE("kernel32.dll", CreateFileA) &&
+#endif  // !defined(_M_ARM64)
+#if !defined(_M_ARM64)
+      TEST_HOOK("kernel32.dll", TlsAlloc, NotEquals, TLS_OUT_OF_INDEXES) &&
+      TEST_HOOK_PARAMS("kernel32.dll", TlsFree, Equals, FALSE,
+                       TLS_OUT_OF_INDEXES) &&
+      TEST_HOOK("kernel32.dll", CloseHandle, Equals, FALSE) &&
+      TEST_HOOK("kernel32.dll", DuplicateHandle, Equals, FALSE) &&
+#endif  // !defined(_M_ARM64)
+      TEST_DETOUR_SKIP_EXEC("kernel32.dll", BaseThreadInitThunk) &&
+#if defined(_M_X64) || defined(_M_ARM64)
+      MAYBE_TEST_HOOK(!IsWin8OrLater(), "kernel32.dll",
+                      RtlInstallFunctionTableCallback, Equals, FALSE) &&
+      TEST_HOOK("user32.dll", GetKeyState, Ignore, 0) &&  // see Bug 1316415
+#endif
+      TEST_HOOK("user32.dll", GetWindowInfo, Equals, FALSE) &&
+      TEST_HOOK("user32.dll", TrackPopupMenu, Equals, FALSE) &&
+      TEST_DETOUR("user32.dll", CreateWindowExW, Equals, nullptr) &&
+      TEST_HOOK("user32.dll", InSendMessageEx, Equals, ISMEX_NOSEND) &&
+      TEST_HOOK("user32.dll", SendMessageTimeoutW, Equals, 0) &&
+      TEST_HOOK("user32.dll", SetCursorPos, NotEquals, FALSE) &&
+      TEST_HOOK("bcrypt.dll", BCryptGenRandom, Equals,
+                static_cast<NTSTATUS>(STATUS_INVALID_HANDLE)) &&
+      TEST_HOOK("advapi32.dll", RtlGenRandom, Equals, TRUE) &&
+#if !defined(_M_ARM64)
+      TEST_HOOK("imm32.dll", ImmGetContext, Equals, nullptr) &&
+#endif  // !defined(_M_ARM64)
+      TEST_HOOK("imm32.dll", ImmGetCompositionStringW, Ignore, 0) &&
+      TEST_HOOK_SKIP_EXEC("imm32.dll", ImmSetCandidateWindow) &&
+      TEST_HOOK("imm32.dll", ImmNotifyIME, Equals, 0) &&
+      TEST_HOOK("comdlg32.dll", GetSaveFileNameW, Ignore, FALSE) &&
+      TEST_HOOK("comdlg32.dll", GetOpenFileNameW, Ignore, FALSE) &&
+#if defined(_M_X64)
+      TEST_HOOK("comdlg32.dll", PrintDlgW, Ignore, 0) &&
+#endif
+      MAYBE_TEST_HOOK(ShouldTestTipTsf(), "tiptsf.dll", ProcessCaretEvents,
+                      Ignore, nullptr) &&
+      TEST_HOOK("wininet.dll", InternetOpenA, NotEquals, nullptr) &&
+      TEST_HOOK("wininet.dll", InternetCloseHandle, Equals, FALSE) &&
+      TEST_HOOK("wininet.dll", InternetConnectA, Equals, nullptr) &&
+      TEST_HOOK("wininet.dll", InternetQueryDataAvailable, Equals, FALSE) &&
+      TEST_HOOK("wininet.dll", InternetReadFile, Equals, FALSE) &&
+      TEST_HOOK("wininet.dll", InternetWriteFile, Equals, FALSE) &&
+      TEST_HOOK("wininet.dll", InternetSetOptionA, Equals, FALSE) &&
+      TEST_HOOK("wininet.dll", HttpAddRequestHeadersA, Equals, FALSE) &&
+      TEST_HOOK("wininet.dll", HttpOpenRequestA, Equals, nullptr) &&
+      TEST_HOOK("wininet.dll", HttpQueryInfoA, Equals, FALSE) &&
+      TEST_HOOK("wininet.dll", HttpSendRequestA, Equals, FALSE) &&
+      TEST_HOOK("wininet.dll", HttpSendRequestExA, Equals, FALSE) &&
+      TEST_HOOK("wininet.dll", HttpEndRequestA, Equals, FALSE) &&
+      TEST_HOOK("wininet.dll", InternetQueryOptionA, Equals, FALSE) &&
+      TEST_HOOK("sspicli.dll", AcquireCredentialsHandleA, NotEquals,
+                SEC_E_OK) &&
+      TEST_HOOK_PARAMS("sspicli.dll", QueryCredentialsAttributesA, Equals,
+                       SEC_E_INVALID_HANDLE, &credHandle, 0, nullptr) &&
+      TEST_HOOK_PARAMS("sspicli.dll", FreeCredentialsHandle, Equals,
+                       SEC_E_INVALID_HANDLE, &credHandle) &&
+#if defined(_M_X64) && !defined(MOZ_CODE_COVERAGE)
+      TestDetouredCallUnwindInfo() &&
+#endif  // defined(_M_X64) && !defined(MOZ_CODE_COVERAGE)
+      // Run TestDynamicCodePolicy() at the end because the policy is
+      // irreversible.
+      TestDynamicCodePolicy()) {
+    printf("TEST-PASS | WindowsDllInterceptor | all checks passed\n");
+
+    LARGE_INTEGER end, freq;
+    QueryPerformanceCounter(&end);
+
+    QueryPerformanceFrequency(&freq);
+
+    LARGE_INTEGER result;
+    result.QuadPart = end.QuadPart - start.QuadPart;
+    result.QuadPart *= 1000000;
+    result.QuadPart /= freq.QuadPart;
+
+    printf("Elapsed time: %lld microseconds\n", result.QuadPart);
+
+    return 0;
+  }
+
+  return 1;
+}
diff --git a/toolkit/xre/dllservices/tests/TestDllInterceptor.exe.manifest b/toolkit/xre/dllservices/tests/TestDllInterceptor.exe.manifest
new file mode 100644
index 0000000000..11287012c5
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/TestDllInterceptor.exe.manifest
@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<assembly xmlns="urn:schemas-microsoft-com:asm.v1"
+          manifestVersion="1.0"
+          xmlns:asmv3="urn:schemas-microsoft-com:asm.v3">
+  <assemblyIdentity type="win32"
+                    name="TestDllInterceptor"
+                    version="1.0.0.0" />
+  <compatibility xmlns="urn:schemas-microsoft-com:compatibility.v1">
+    <application>
+      <!-- Need this to use functions in WindowsVersion.h -->
+      <supportedOS Id="{8e0f7a12-bfb3-4fe8-b9a5-48fd50a15a9a}"/> <!-- Win10 -->
+      <supportedOS Id="{1f676c76-80e1-4239-95bb-83d0f6d0da78}"/> <!-- Win8.1 -->
+      <supportedOS Id="{4a2f28e3-53b9-4441-ba9c-d69d4a4a6e38}"/> <!-- Win8 -->
+      <supportedOS Id="{35138b9a-5d96-4fbd-8e2d-a2440225f93a}"/> <!-- Win7 -->
+    </application>
+  </compatibility>
+</assembly>
diff --git a/toolkit/xre/dllservices/tests/TestDllInterceptorCrossProcess.cpp b/toolkit/xre/dllservices/tests/TestDllInterceptorCrossProcess.cpp
new file mode 100644
index 0000000000..32cf90bac1
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/TestDllInterceptorCrossProcess.cpp
@@ -0,0 +1,159 @@
+/* -*- 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/. */
+
+#include "mozilla/Attributes.h"
+#include "mozilla/ArrayUtils.h"
+#include "mozilla/CmdLineAndEnvUtils.h"
+#include "nsWindowsDllInterceptor.h"
+#include "nsWindowsHelpers.h"
+
+#include <string>
+
+using std::wstring;
+
+extern "C" __declspec(dllexport) int ReturnResult() { return 2; }
+
+static mozilla::CrossProcessDllInterceptor::FuncHookType<
+    decltype(&ReturnResult)>
+    gOrigReturnResult;
+
+static int ReturnResultHook() {
+  if (gOrigReturnResult() != 2) {
+    return 3;
+  }
+
+  return 0;
+}
+
+int ParentMain(int argc, wchar_t* argv[]) {
+  mozilla::SetArgv0ToFullBinaryPath(argv);
+
+  // We'll add the child process to a job so that, in the event of a failure in
+  // this parent process, the child process will be automatically terminated.
+  nsAutoHandle job(::CreateJobObjectW(nullptr, nullptr));
+  if (!job) {
+    printf(
+        "TEST-UNEXPECTED-FAIL | DllInterceptorCrossProcess | Job creation "
+        "failed\n");
+    return 1;
+  }
+
+  JOBOBJECT_EXTENDED_LIMIT_INFORMATION jobInfo = {};
+  jobInfo.BasicLimitInformation.LimitFlags = JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE;
+
+  if (!::SetInformationJobObject(job.get(), JobObjectExtendedLimitInformation,
+                                 &jobInfo, sizeof(jobInfo))) {
+    printf(
+        "TEST-UNEXPECTED-FAIL | DllInterceptorCrossProcess | Job config "
+        "failed\n");
+    return 1;
+  }
+
+  wchar_t childArgv_1[] = L"-child";
+
+  wchar_t* childArgv[] = {argv[0], childArgv_1};
+
+  mozilla::UniquePtr<wchar_t[]> cmdLine(
+      mozilla::MakeCommandLine(mozilla::ArrayLength(childArgv), childArgv));
+
+  STARTUPINFOW si = {sizeof(si)};
+  PROCESS_INFORMATION pi;
+  if (!::CreateProcessW(argv[0], cmdLine.get(), nullptr, nullptr, FALSE,
+                        CREATE_SUSPENDED, nullptr, nullptr, &si, &pi)) {
+    printf(
+        "TEST-UNEXPECTED-FAIL | DllInterceptorCrossProcess | Failed to spawn "
+        "child process\n");
+    return 1;
+  }
+
+  nsAutoHandle childProcess(pi.hProcess);
+  nsAutoHandle childMainThread(pi.hThread);
+
+  if (!::AssignProcessToJobObject(job.get(), childProcess.get())) {
+    printf(
+        "TEST-UNEXPECTED-FAIL | DllInterceptorCrossProcess | Failed to assign "
+        "child process to job\n");
+    ::TerminateProcess(childProcess.get(), 1);
+    return 1;
+  }
+
+  mozilla::nt::CrossExecTransferManager transferMgr(childProcess);
+  if (!transferMgr) {
+    printf(
+        "TEST-UNEXPECTED-FAIL | DllInterceptorCrossProcess | "
+        "CrossExecTransferManager instantiation failed.\n");
+    return 1;
+  }
+
+  mozilla::CrossProcessDllInterceptor intcpt(childProcess.get());
+  intcpt.Init("TestDllInterceptorCrossProcess.exe");
+
+  if (!gOrigReturnResult.Set(transferMgr, intcpt, "ReturnResult",
+                             &ReturnResultHook)) {
+    printf(
+        "TEST-UNEXPECTED-FAIL | DllInterceptorCrossProcess | Failed to add "
+        "hook\n");
+    return 1;
+  }
+
+  printf("TEST-PASS | DllInterceptorCrossProcess | Hook added\n");
+
+  if (::ResumeThread(childMainThread.get()) == static_cast<DWORD>(-1)) {
+    printf(
+        "TEST-UNEXPECTED-FAIL | DllInterceptorCrossProcess | Failed to resume "
+        "child thread\n");
+    return 1;
+  }
+
+  BOOL remoteDebugging;
+  bool debugging =
+      ::IsDebuggerPresent() ||
+      (::CheckRemoteDebuggerPresent(childProcess.get(), &remoteDebugging) &&
+       remoteDebugging);
+
+  DWORD waitResult =
+      ::WaitForSingleObject(childProcess.get(), debugging ? INFINITE : 60000);
+  if (waitResult != WAIT_OBJECT_0) {
+    printf(
+        "TEST-UNEXPECTED-FAIL | DllInterceptorCrossProcess | Child process "
+        "failed to finish\n");
+    return 1;
+  }
+
+  DWORD childExitCode;
+  if (!::GetExitCodeProcess(childProcess.get(), &childExitCode)) {
+    printf(
+        "TEST-UNEXPECTED-FAIL | DllInterceptorCrossProcess | Failed to obtain "
+        "child process exit code\n");
+    return 1;
+  }
+
+  if (childExitCode) {
+    printf(
+        "TEST-UNEXPECTED-FAIL | DllInterceptorCrossProcess | Child process "
+        "exit code is %lu instead of 0\n",
+        childExitCode);
+    return 1;
+  }
+
+  printf(
+      "TEST-PASS | DllInterceptorCrossProcess | Child process exit code is "
+      "zero\n");
+  return 0;
+}
+
+extern "C" int wmain(int argc, wchar_t* argv[]) {
+  if (argc > 1) {
+    // clang keeps inlining this call despite every attempt to force it to do
+    // otherwise. We'll use GetProcAddress and call its function pointer
+    // instead.
+    auto pReturnResult = reinterpret_cast<decltype(&ReturnResult)>(
+        ::GetProcAddress(::GetModuleHandleW(nullptr), "ReturnResult"));
+    return pReturnResult();
+  }
+
+  return ParentMain(argc, argv);
+}
diff --git a/toolkit/xre/dllservices/tests/TestIATPatcher.cpp b/toolkit/xre/dllservices/tests/TestIATPatcher.cpp
new file mode 100644
index 0000000000..2f84c0541a
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/TestIATPatcher.cpp
@@ -0,0 +1,121 @@
+/* -*- 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/. */
+
+#include "mozilla/Assertions.h"
+#include "mozilla/DynamicallyLinkedFunctionPtr.h"
+#include "nsWindowsDllInterceptor.h"
+#include "nsWindowsHelpers.h"
+
+#include <shlwapi.h>
+
+static int NormalImport() { return ::GetSystemMetrics(SM_CYCAPTION); }
+
+static bool DelayLoadImport() {
+  return !!::UrlIsW(L"http://example.com/", URLIS_FILEURL);
+}
+
+static mozilla::WindowsIATPatcher::FuncHookType<decltype(&::GetSystemMetrics)>
+    gGetSystemMetricsHook;
+
+static mozilla::WindowsIATPatcher::FuncHookType<decltype(&::MessageBoxA)>
+    gMessageBoxAHook;
+
+static mozilla::WindowsIATPatcher::FuncHookType<decltype(&::UrlIsW)> gUrlIsHook;
+
+static bool gGetSystemMetricsHookCalled = false;
+
+static int WINAPI GetSystemMetricsHook(int aIndex) {
+  MOZ_DIAGNOSTIC_ASSERT(aIndex == SM_CYCAPTION);
+  gGetSystemMetricsHookCalled = true;
+  return 0;
+}
+
+static bool gUrlIsHookCalled = false;
+
+static BOOL WINAPI UrlIsWHook(PCWSTR aUrl, URLIS aFlags) {
+  gUrlIsHookCalled = true;
+  return TRUE;
+}
+
+static HMODULE GetStrongReferenceToExeModule() {
+  HMODULE result;
+  if (!::GetModuleHandleExW(0, nullptr, &result)) {
+    return nullptr;
+  }
+
+  return result;
+}
+
+#define PRINT_FAIL(msg) printf("TEST-UNEXPECTED-FAIL | IATPatcher | " msg "\n")
+
+extern "C" int wmain(int argc, wchar_t* argv[]) {
+  nsModuleHandle ourModule1(GetStrongReferenceToExeModule());
+  if (!ourModule1) {
+    PRINT_FAIL("Failed obtaining HMODULE for executable");
+    return 1;
+  }
+
+  if (!gGetSystemMetricsHook.Set(ourModule1, "user32.dll", "GetSystemMetrics",
+                                 &GetSystemMetricsHook)) {
+    PRINT_FAIL("Failed setting GetSystemMetrics hook");
+    return 1;
+  }
+
+  if (NormalImport() || !gGetSystemMetricsHookCalled) {
+    PRINT_FAIL("GetSystemMetrics hook was not called");
+    return 1;
+  }
+
+  static const mozilla::StaticDynamicallyLinkedFunctionPtr<
+      decltype(&::GetSystemMetrics)>
+      pRealGetSystemMetrics(L"user32.dll", "GetSystemMetrics");
+  if (!pRealGetSystemMetrics) {
+    PRINT_FAIL("Failed resolving real GetSystemMetrics pointer");
+    return 1;
+  }
+
+  if (gGetSystemMetricsHook.GetStub() != pRealGetSystemMetrics) {
+    PRINT_FAIL(
+        "GetSystemMetrics hook stub pointer does not match real "
+        "GetSystemMetrics pointer");
+    return 1;
+  }
+
+  nsModuleHandle ourModule2(GetStrongReferenceToExeModule());
+  if (!ourModule2) {
+    PRINT_FAIL("Failed obtaining HMODULE for executable");
+    return 1;
+  }
+
+  // This should fail becuase the test never calls, and thus never imports,
+  // MessageBoxA
+  if (gMessageBoxAHook.Set(ourModule2, "user32.dll", "MessageBoxA", nullptr)) {
+    PRINT_FAIL("Setting MessageBoxA hook succeeded when it should have failed");
+    return 1;
+  }
+
+  nsModuleHandle ourModule3(GetStrongReferenceToExeModule());
+  if (!ourModule3) {
+    PRINT_FAIL("Failed obtaining HMODULE for executable");
+    return 1;
+  }
+
+  // These tests involve a delay-loaded import, which are not supported; we
+  // expect these tests to FAIL.
+
+  if (gUrlIsHook.Set(ourModule3, "shlwapi.dll", "UrlIsW", &UrlIsWHook)) {
+    PRINT_FAIL("gUrlIsHook.Set should have failed");
+    return 1;
+  }
+
+  if (DelayLoadImport() || gUrlIsHookCalled) {
+    PRINT_FAIL("gUrlIsHook should not have been called");
+    return 1;
+  }
+
+  printf("TEST-PASS | IATPatcher | All tests passed.\n");
+  return 0;
+}
diff --git a/toolkit/xre/dllservices/tests/TestMMPolicy.cpp b/toolkit/xre/dllservices/tests/TestMMPolicy.cpp
new file mode 100644
index 0000000000..1ae93a4ed1
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/TestMMPolicy.cpp
@@ -0,0 +1,204 @@
+/* -*- 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/. */
+
+#include "nsWindowsDllInterceptor.h"
+
+#include <functional>
+
+mozilla::interceptor::MMPolicyInProcess gPolicy;
+
+void DepleteVirtualAddress(
+    uint8_t* aStart, size_t aSize,
+    const std::function<void(void*)>& aPostAllocCallback) {
+  const DWORD granularity = gPolicy.GetAllocGranularity();
+  if (aStart == 0 || aSize < granularity) {
+    return;
+  }
+
+  uint8_t* alignedStart = reinterpret_cast<uint8_t*>(
+      (((reinterpret_cast<uintptr_t>(aStart) - 1) / granularity) + 1) *
+      granularity);
+  aSize -= (alignedStart - aStart);
+  if (auto p = VirtualAlloc(alignedStart, aSize, MEM_RESERVE, PAGE_NOACCESS)) {
+    aPostAllocCallback(p);
+    return;
+  }
+
+  uintptr_t mask = ~(static_cast<uintptr_t>(granularity) - 1);
+  size_t halfSize = (aSize >> 1) & mask;
+  if (halfSize == 0) {
+    return;
+  }
+
+  DepleteVirtualAddress(aStart, halfSize, aPostAllocCallback);
+  DepleteVirtualAddress(aStart + halfSize, aSize - halfSize,
+                        aPostAllocCallback);
+}
+
+bool ValidateFreeRegion(LPVOID aRegion, size_t aDesiredLen) {
+  MEMORY_BASIC_INFORMATION mbi;
+  if (VirtualQuery(aRegion, &mbi, sizeof(mbi)) != sizeof(mbi)) {
+    printf(
+        "TEST-FAILED | TestMMPolicy | "
+        "VirtualQuery(%p) failed - %08lx\n",
+        aRegion, GetLastError());
+    return false;
+  }
+
+  if (mbi.State != MEM_FREE) {
+    printf(
+        "TEST-FAILED | TestMMPolicy | "
+        "%p is not within a free region\n",
+        aRegion);
+    return false;
+  }
+
+  if (aRegion != mbi.BaseAddress ||
+      reinterpret_cast<uintptr_t>(mbi.BaseAddress) %
+          gPolicy.GetAllocGranularity()) {
+    printf(
+        "TEST-FAILED | TestMMPolicy | "
+        "%p is not a region's start address\n",
+        aRegion);
+    return false;
+  }
+
+  LPVOID allocated = VirtualAlloc(aRegion, aDesiredLen,
+                                  MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE);
+  if (!allocated) {
+    printf(
+        "TEST-FAILED | TestMMPolicy | "
+        "VirtualAlloc(%p) failed - %08lx\n",
+        aRegion, GetLastError());
+    return false;
+  }
+
+  if (!VirtualFree(allocated, 0, MEM_RELEASE)) {
+    printf(
+        "TEST-FAILED | TestMMPolicy | "
+        "VirtualFree(%p) failed - %08lx\n",
+        allocated, GetLastError());
+    return false;
+  }
+
+  return true;
+}
+
+bool TestFindRegion() {
+  // Skip the near-null addresses
+  uint8_t* minAddr = reinterpret_cast<uint8_t*>(
+      std::max(gPolicy.GetAllocGranularity(), 0x1000000ul));
+  // 64bit address space is too large to deplete.  32bit space is enough.
+  uint8_t* maxAddr = reinterpret_cast<uint8_t*>(std::min(
+      gPolicy.GetMaxUserModeAddress(), static_cast<uintptr_t>(0xffffffff)));
+
+  // Keep one of the regions we allocate so that we can release it later.
+  void* lastResort = nullptr;
+
+  // Reserve all free regions in the range [minAddr, maxAddr]
+  for (uint8_t* address = minAddr; address <= maxAddr;) {
+    MEMORY_BASIC_INFORMATION mbi;
+    if (VirtualQuery(address, &mbi, sizeof(mbi)) != sizeof(mbi)) {
+      printf(
+          "TEST-FAILED | TestMMPolicy | "
+          "VirtualQuery(%p) failed - %08lx\n",
+          address, GetLastError());
+      break;
+    }
+
+    address = reinterpret_cast<uint8_t*>(mbi.BaseAddress);
+    if (mbi.State == MEM_FREE) {
+      DepleteVirtualAddress(address, mbi.RegionSize,
+                            [&lastResort](void* aAllocated) {
+                              // Pick the first address we allocate to make sure
+                              // FindRegion scans the full range.
+                              if (!lastResort) {
+                                lastResort = aAllocated;
+                              }
+                            });
+    }
+
+    address += mbi.RegionSize;
+  }
+
+  if (!lastResort) {
+    printf(
+        "TEST-SKIPPED | TestMMPolicy | "
+        "No free region in [%p - %p].  Skipping the testcase.\n",
+        minAddr, maxAddr);
+    return true;
+  }
+
+  // Make sure there are no free regions
+  PVOID freeRegion =
+      gPolicy.FindRegion(GetCurrentProcess(), 1, minAddr, maxAddr);
+  if (freeRegion) {
+    if (reinterpret_cast<uintptr_t>(freeRegion) %
+        gPolicy.GetAllocGranularity()) {
+      printf(
+          "TEST-FAILED | TestMMPolicy | "
+          "MMPolicyBase::FindRegion returned an unaligned address %p.\n",
+          freeRegion);
+      return false;
+    }
+
+    printf(
+        "TEST-SKIPPED | TestMMPolicy | "
+        "%p was freed after depletion.  Skipping the testcase.\n",
+        freeRegion);
+    return true;
+  }
+
+  // Free one region, and thus we can expect FindRegion finds this region
+  if (!VirtualFree(lastResort, 0, MEM_RELEASE)) {
+    printf(
+        "TEST-FAILED | TestMMPolicy | "
+        "VirtualFree(%p) failed - %08lx\n",
+        lastResort, GetLastError());
+    return false;
+  }
+  printf("The region starting from %p has been freed.\n", lastResort);
+
+  // Run the function several times because it uses a randon number inside
+  // and its result is nondeterministic.
+  for (int i = 0; i < 50; ++i) {
+    // Because one region was freed, a desire up to one region
+    // should be fulfilled.
+    const size_t desiredLengths[] = {1, gPolicy.GetAllocGranularity()};
+
+    for (auto desiredLen : desiredLengths) {
+      freeRegion =
+          gPolicy.FindRegion(GetCurrentProcess(), desiredLen, minAddr, maxAddr);
+      if (!freeRegion) {
+        printf(
+            "TEST-FAILED | TestMMPolicy | "
+            "Failed to find a free region.\n");
+        return false;
+      }
+
+      if (!ValidateFreeRegion(freeRegion, desiredLen)) {
+        return false;
+      }
+    }
+  }
+
+  return true;
+}
+
+extern "C" int wmain(int argc, wchar_t* argv[]) {
+  // Preload delayload modules (e.g. advapi32.dll, bcryptPrimitives.dll, etc.)
+  // by calling rand_s(), which is used in MMPolicy::FindRegion, before
+  // depleting the process memory during the test.
+  unsigned int rnd = 0;
+  rand_s(&rnd);
+
+  if (!TestFindRegion()) {
+    return 1;
+  }
+
+  printf("TEST-PASS | TestMMPolicy | All tests passed.\n");
+  return 0;
+}
diff --git a/toolkit/xre/dllservices/tests/gtest/TestDLLBlocklist.cpp b/toolkit/xre/dllservices/tests/gtest/TestDLLBlocklist.cpp
new file mode 100644
index 0000000000..938f63a524
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/TestDLLBlocklist.cpp
@@ -0,0 +1,475 @@
+/* -*- 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/. */
+
+#include <windows.h>
+#include <winternl.h>
+
+#include <process.h>
+
+#include <array>
+#include <functional>
+
+#include "gtest/gtest.h"
+
+#include "mozilla/ArrayUtils.h"
+#include "mozilla/Char16.h"
+#include "mozilla/gtest/MozAssertions.h"
+#include "mozilla/Services.h"
+#include "mozilla/WinDllServices.h"
+#include "mozilla/WindowsStackCookie.h"
+#include "nsDirectoryServiceDefs.h"
+#include "nsDirectoryServiceUtils.h"
+#include "nsIObserver.h"
+#include "nsIObserverService.h"
+#include "nsIThread.h"
+#include "nsReadableUtils.h"
+#include "nsString.h"
+#include "nsTArray.h"
+#include "nsUnicharUtils.h"
+#include "nsWindowsHelpers.h"
+
+static nsString GetFullPath(const nsAString& aLeaf) {
+  nsCOMPtr<nsIFile> f;
+
+  EXPECT_TRUE(NS_SUCCEEDED(
+      NS_GetSpecialDirectory(NS_OS_CURRENT_WORKING_DIR, getter_AddRefs(f))));
+
+  EXPECT_NS_SUCCEEDED(f->Append(aLeaf));
+
+  bool exists;
+  EXPECT_TRUE(NS_SUCCEEDED(f->Exists(&exists)) && exists);
+
+  nsString ret;
+  EXPECT_NS_SUCCEEDED(f->GetPath(ret));
+  return ret;
+}
+
+void FlushMainThreadLoop() {
+  nsCOMPtr<nsIThread> mainThread;
+  nsresult rv = NS_GetMainThread(getter_AddRefs(mainThread));
+  ASSERT_NS_SUCCEEDED(rv);
+
+  rv = NS_OK;
+  bool processed = true;
+  while (processed && NS_SUCCEEDED(rv)) {
+    rv = mainThread->ProcessNextEvent(false, &processed);
+  }
+}
+
+class TestDLLLoadObserver : public nsIObserver {
+ public:
+  using DLLFilter = std::function<bool(const char16_t*)>;
+
+  explicit TestDLLLoadObserver(DLLFilter dllFilter)
+      : mDllFilter(std::move(dllFilter)),
+        mMainThreadNotificationsCount(0),
+        mNonMainThreadNotificationsCount(0){};
+
+  NS_DECL_THREADSAFE_ISUPPORTS
+
+  NS_IMETHOD Observe(nsISupports* aSubject, const char* aTopic,
+                     const char16_t* aData) override {
+    if (!mDllFilter(aData)) {
+      return NS_OK;
+    }
+    if (0 == strcmp(aTopic, mozilla::DllServices::kTopicDllLoadedMainThread)) {
+      ++mMainThreadNotificationsCount;
+    } else {
+      EXPECT_TRUE(
+          0 ==
+          strcmp(aTopic, mozilla::DllServices::kTopicDllLoadedNonMainThread));
+      ++mNonMainThreadNotificationsCount;
+    }
+    return NS_OK;
+  }
+
+  void Init() {
+    nsCOMPtr<nsIObserverService> obsServ(
+        mozilla::services::GetObserverService());
+
+    EXPECT_TRUE(obsServ);
+
+    obsServ->AddObserver(this, mozilla::DllServices::kTopicDllLoadedMainThread,
+                         false);
+    obsServ->AddObserver(
+        this, mozilla::DllServices::kTopicDllLoadedNonMainThread, false);
+  }
+
+  void Exit() {
+    // Observe only gets called if/when we flush the main thread loop.
+    FlushMainThreadLoop();
+
+    nsCOMPtr<nsIObserverService> obsServ(
+        mozilla::services::GetObserverService());
+
+    EXPECT_TRUE(obsServ);
+
+    obsServ->RemoveObserver(this,
+                            mozilla::DllServices::kTopicDllLoadedMainThread);
+    obsServ->RemoveObserver(this,
+                            mozilla::DllServices::kTopicDllLoadedNonMainThread);
+  }
+
+  int MainThreadNotificationsCount() { return mMainThreadNotificationsCount; }
+
+  int NonMainThreadNotificationsCount() {
+    return mNonMainThreadNotificationsCount;
+  }
+
+ private:
+  virtual ~TestDLLLoadObserver() = default;
+
+  DLLFilter mDllFilter;
+  int mMainThreadNotificationsCount;
+  int mNonMainThreadNotificationsCount;
+};
+
+NS_IMPL_ISUPPORTS(TestDLLLoadObserver, nsIObserver)
+
+TEST(TestDllBlocklist, BlockDllByName)
+{
+  // The DLL name has capital letters, so this also tests that the comparison
+  // is case-insensitive.
+  constexpr auto kLeafName = u"TestDllBlocklist_MatchByName.dll"_ns;
+  nsString dllPath = GetFullPath(kLeafName);
+
+  nsModuleHandle hDll(::LoadLibraryW(dllPath.get()));
+
+  EXPECT_TRUE(!hDll);
+  EXPECT_TRUE(!::GetModuleHandleW(kLeafName.get()));
+
+  hDll.own(::LoadLibraryExW(dllPath.get(), nullptr, LOAD_LIBRARY_AS_DATAFILE));
+  // Mapped as MEM_MAPPED + PAGE_READONLY
+  EXPECT_TRUE(hDll);
+}
+
+TEST(TestDllBlocklist, BlockDllByVersion)
+{
+  constexpr auto kLeafName = u"TestDllBlocklist_MatchByVersion.dll"_ns;
+  nsString dllPath = GetFullPath(kLeafName);
+
+  nsModuleHandle hDll(::LoadLibraryW(dllPath.get()));
+
+  EXPECT_TRUE(!hDll);
+  EXPECT_TRUE(!::GetModuleHandleW(kLeafName.get()));
+
+  hDll.own(
+      ::LoadLibraryExW(dllPath.get(), nullptr, LOAD_LIBRARY_AS_IMAGE_RESOURCE));
+  // Mapped as MEM_IMAGE + PAGE_READONLY
+  EXPECT_TRUE(hDll);
+}
+
+TEST(TestDllBlocklist, AllowDllByVersion)
+{
+  constexpr auto kLeafName = u"TestDllBlocklist_AllowByVersion.dll"_ns;
+  nsString dllPath = GetFullPath(kLeafName);
+
+  nsModuleHandle hDll(::LoadLibraryW(dllPath.get()));
+
+  EXPECT_TRUE(!!hDll);
+  EXPECT_TRUE(!!::GetModuleHandleW(kLeafName.get()));
+}
+
+TEST(TestDllBlocklist, GPUProcessOnly_AllowInMainProcess)
+{
+  constexpr auto kLeafName = u"TestDllBlocklist_GPUProcessOnly.dll"_ns;
+  nsString dllPath = GetFullPath(kLeafName);
+
+  nsModuleHandle hDll(::LoadLibraryW(dllPath.get()));
+
+  EXPECT_TRUE(!!hDll);
+  EXPECT_TRUE(!!::GetModuleHandleW(kLeafName.get()));
+}
+
+TEST(TestDllBlocklist, SocketProcessOnly_AllowInMainProcess)
+{
+  constexpr auto kLeafName = u"TestDllBlocklist_SocketProcessOnly.dll"_ns;
+  nsString dllPath = GetFullPath(kLeafName);
+
+  nsModuleHandle hDll(::LoadLibraryW(dllPath.get()));
+
+  EXPECT_TRUE(!!hDll);
+  EXPECT_TRUE(!!::GetModuleHandleW(kLeafName.get()));
+}
+
+TEST(TestDllBlocklist, UtilityProcessOnly_AllowInMainProcess)
+{
+  constexpr auto kLeafName = u"TestDllBlocklist_UtilityProcessOnly.dll"_ns;
+  nsString dllPath = GetFullPath(kLeafName);
+
+  nsModuleHandle hDll(::LoadLibraryW(dllPath.get()));
+
+  EXPECT_TRUE(!!hDll);
+  EXPECT_TRUE(!!::GetModuleHandleW(kLeafName.get()));
+}
+
+TEST(TestDllBlocklist, GMPluginProcessOnly_AllowInMainProcess)
+{
+  constexpr auto kLeafName = u"TestDllBlocklist_GMPluginProcessOnly.dll"_ns;
+  nsString dllPath = GetFullPath(kLeafName);
+
+  nsModuleHandle hDll(::LoadLibraryW(dllPath.get()));
+
+  EXPECT_TRUE(!!hDll);
+  EXPECT_TRUE(!!::GetModuleHandleW(kLeafName.get()));
+}
+
+// This DLL has two entries; it's blocked for unversioned (i.e. DLLs that
+// have no version information) everywhere and blocked for versions 5.5.5.5 and
+// earlier only in the GPU process. Since the version we're trying to load
+// is 5.5.5.5, it should load in the main process.
+TEST(TestDllBlocklist, MultipleEntriesDifferentProcesses_AllowInMainProcess)
+{
+  constexpr auto kLeafName =
+      u"TestDllBlocklist_MultipleEntries_DifferentProcesses.dll"_ns;
+  nsString dllPath = GetFullPath(kLeafName);
+
+  nsModuleHandle hDll(::LoadLibraryW(dllPath.get()));
+
+  EXPECT_TRUE(!!hDll);
+  EXPECT_TRUE(!!::GetModuleHandleW(kLeafName.get()));
+}
+
+TEST(TestDllBlocklist, MultipleEntriesSameProcessBackward_Block)
+{
+  // One entry matches by version and many others do not, so
+  // we should block.
+  constexpr auto kLeafName =
+      u"TestDllBlocklist_MultipleEntries_SameProcessBackward.dll"_ns;
+  nsString dllPath = GetFullPath(kLeafName);
+
+  nsModuleHandle hDll(::LoadLibraryW(dllPath.get()));
+
+  EXPECT_TRUE(!hDll);
+  EXPECT_TRUE(!::GetModuleHandleW(kLeafName.get()));
+
+  hDll.own(
+      ::LoadLibraryExW(dllPath.get(), nullptr, LOAD_LIBRARY_AS_IMAGE_RESOURCE));
+  // Mapped as MEM_IMAGE + PAGE_READONLY
+  EXPECT_TRUE(hDll);
+}
+
+TEST(TestDllBlocklist, MultipleEntriesSameProcessForward_Block)
+{
+  // One entry matches by version and many others do not, so
+  // we should block.
+  constexpr auto kLeafName =
+      u"TestDllBlocklist_MultipleEntries_SameProcessForward.dll"_ns;
+  nsString dllPath = GetFullPath(kLeafName);
+
+  nsModuleHandle hDll(::LoadLibraryW(dllPath.get()));
+
+  EXPECT_TRUE(!hDll);
+  EXPECT_TRUE(!::GetModuleHandleW(kLeafName.get()));
+
+  hDll.own(
+      ::LoadLibraryExW(dllPath.get(), nullptr, LOAD_LIBRARY_AS_IMAGE_RESOURCE));
+  // Mapped as MEM_IMAGE + PAGE_READONLY
+  EXPECT_TRUE(hDll);
+}
+
+#if defined(MOZ_LAUNCHER_PROCESS)
+// RedirectToNoOpEntryPoint needs the launcher process.
+// This test will fail in debug x64 if we mistakenly reintroduce stack buffers
+// in patched_NtMapViewOfSection (see bug 1733532).
+TEST(TestDllBlocklist, NoOpEntryPoint)
+{
+  // DllMain of this dll has MOZ_RELEASE_ASSERT.  This test makes sure we load
+  // the module successfully without running DllMain.
+  constexpr auto kLeafName = u"TestDllBlocklist_NoOpEntryPoint.dll"_ns;
+  nsString dllPath = GetFullPath(kLeafName);
+
+  nsModuleHandle hDll(::LoadLibraryW(dllPath.get()));
+
+#  if defined(MOZ_ASAN)
+  // With ASAN, the test uses mozglue's blocklist where
+  // REDIRECT_TO_NOOP_ENTRYPOINT is ignored.  So LoadLibraryW
+  // is expected to fail.
+  EXPECT_TRUE(!hDll);
+  EXPECT_TRUE(!::GetModuleHandleW(kLeafName.get()));
+#  else
+  EXPECT_TRUE(!!hDll);
+  EXPECT_TRUE(!!::GetModuleHandleW(kLeafName.get()));
+#  endif
+}
+
+// User blocklist needs the launcher process.
+// This test will fail in debug x64 if we mistakenly reintroduce stack buffers
+// in patched_NtMapViewOfSection (see bug 1733532).
+TEST(TestDllBlocklist, UserBlocked)
+{
+  constexpr auto kLeafName = u"TestDllBlocklist_UserBlocked.dll"_ns;
+  nsString dllPath = GetFullPath(kLeafName);
+
+  nsModuleHandle hDll(::LoadLibraryW(dllPath.get()));
+
+// With ASAN, the test uses mozglue's blocklist where
+// the user blocklist is not used.
+#  if !defined(MOZ_ASAN)
+  EXPECT_TRUE(!hDll);
+  EXPECT_TRUE(!::GetModuleHandleW(kLeafName.get()));
+#  endif
+  hDll.own(::LoadLibraryExW(dllPath.get(), nullptr, LOAD_LIBRARY_AS_DATAFILE));
+  // Mapped as MEM_MAPPED + PAGE_READONLY
+  EXPECT_TRUE(hDll);
+}
+#endif  // defined(MOZ_LAUNCHER_PROCESS)
+
+#define DLL_BLOCKLIST_ENTRY(name, ...) {name, __VA_ARGS__},
+#define DLL_BLOCKLIST_STRING_TYPE const char*
+#include "mozilla/WindowsDllBlocklistLegacyDefs.h"
+
+TEST(TestDllBlocklist, BlocklistIntegrity)
+{
+  DECLARE_POINTER_TO_FIRST_DLL_BLOCKLIST_ENTRY(pFirst);
+  DECLARE_POINTER_TO_LAST_DLL_BLOCKLIST_ENTRY(pLast);
+
+  EXPECT_FALSE(pLast->mName || pLast->mMaxVersion || pLast->mFlags);
+
+  for (size_t i = 0; i < mozilla::ArrayLength(gWindowsDllBlocklist) - 1; ++i) {
+    auto pEntry = pFirst + i;
+
+    // Validate name
+    EXPECT_TRUE(!!pEntry->mName);
+    EXPECT_GT(strlen(pEntry->mName), 3U);
+
+    // Check the filename for valid characters.
+    for (auto pch = pEntry->mName; *pch != 0; ++pch) {
+      EXPECT_FALSE(*pch >= 'A' && *pch <= 'Z');
+    }
+  }
+}
+
+TEST(TestDllBlocklist, BlockThreadWithLoadLibraryEntryPoint)
+{
+  // Only supported on Nightly
+#if defined(NIGHTLY_BUILD)
+  using ThreadProc = unsigned(__stdcall*)(void*);
+
+  constexpr auto kLeafNameW = u"TestDllBlocklist_MatchByVersion.dll"_ns;
+
+  nsString fullPathW = GetFullPath(kLeafNameW);
+  EXPECT_FALSE(fullPathW.IsEmpty());
+
+  nsAutoHandle threadW(reinterpret_cast<HANDLE>(
+      _beginthreadex(nullptr, 0, reinterpret_cast<ThreadProc>(&::LoadLibraryW),
+                     (void*)fullPathW.get(), 0, nullptr)));
+
+  EXPECT_TRUE(!!threadW);
+  EXPECT_EQ(::WaitForSingleObject(threadW, INFINITE), WAIT_OBJECT_0);
+
+#  if !defined(MOZ_ASAN)
+  // ASAN builds under Windows 11 can have unexpected thread exit codes.
+  // See bug 1798796
+  DWORD exitCode;
+  EXPECT_TRUE(::GetExitCodeThread(threadW, &exitCode) && !exitCode);
+#  endif  // !defined(MOZ_ASAN)
+  EXPECT_TRUE(!::GetModuleHandleW(kLeafNameW.get()));
+
+  const NS_LossyConvertUTF16toASCII fullPathA(fullPathW);
+  EXPECT_FALSE(fullPathA.IsEmpty());
+
+  nsAutoHandle threadA(reinterpret_cast<HANDLE>(
+      _beginthreadex(nullptr, 0, reinterpret_cast<ThreadProc>(&::LoadLibraryA),
+                     (void*)fullPathA.get(), 0, nullptr)));
+
+  EXPECT_TRUE(!!threadA);
+  EXPECT_EQ(::WaitForSingleObject(threadA, INFINITE), WAIT_OBJECT_0);
+#  if !defined(MOZ_ASAN)
+  // ASAN builds under Windows 11 can have unexpected thread exit codes.
+  // See bug 1798796
+  EXPECT_TRUE(::GetExitCodeThread(threadA, &exitCode) && !exitCode);
+#  endif  // !defined(MOZ_ASAN)
+  EXPECT_TRUE(!::GetModuleHandleW(kLeafNameW.get()));
+#endif  // defined(NIGHTLY_BUILD)
+}
+
+constexpr auto kSingleNotificationDll1Loads = 4;
+constexpr auto kSingleNotificationDll2Loads = 3;
+using DllFullPathsArray =
+    std::array<nsString,
+               kSingleNotificationDll1Loads + kSingleNotificationDll2Loads>;
+
+DWORD __stdcall LoadSingleNotificationModules(LPVOID aThreadParameter) {
+  auto* dllFullPaths = reinterpret_cast<DllFullPathsArray*>(aThreadParameter);
+
+  for (const auto& dllFullPath : *dllFullPaths) {
+    nsModuleHandle hDll(::LoadLibraryW(dllFullPath.get()));
+    EXPECT_TRUE(!hDll);
+    EXPECT_TRUE(!::GetModuleHandleW(dllFullPath.get()));
+  }
+
+  return 0;
+}
+
+// The next test is only relevant if we hook LdrLoadDll, so we reflect the
+// hooking condition from browser/app/winlauncher/DllBlocklistInit.cpp.
+#if !defined(MOZ_ASAN) && !defined(_M_ARM64)
+
+// This test relies on the fact that blocked DLL loads generate a DLL load
+// notification.
+TEST(TestDllBlocklist, SingleNotification)
+{
+  // We will block-load the two DLLs multiple times, with variations on case.
+  std::array<nsLiteralString, kSingleNotificationDll1Loads> dll1Variations{
+      u"TestDllBlocklist_SingleNotification1.dll"_ns,
+      u"TestDllBlocklist_SingleNotification1.dll"_ns,
+      u"testdllblocklist_singlenotification1.dll"_ns,
+      u"TeStDlLbLoCkLiSt_SiNgLeNoTiFiCaTiOn1.DlL"_ns,
+  };
+  std::array<nsLiteralString, kSingleNotificationDll2Loads> dll2Variations{
+      u"TestDllBlocklist_SingleNotification2.dll"_ns,
+      u"testdllblocklist_singlenotification2.dll"_ns,
+      u"TESTDLLBLOCKLIST_SINGLENOTIFICATION2.dll"_ns,
+  };
+  DllFullPathsArray dllFullPaths;
+  size_t i = 0;
+  for (const auto& dllName : dll1Variations) {
+    dllFullPaths[i] = GetFullPath(dllName);
+    ++i;
+  }
+  for (const auto& dllName : dll2Variations) {
+    dllFullPaths[i] = GetFullPath(dllName);
+    ++i;
+  }
+
+  // Register our observer.
+  TestDLLLoadObserver::DLLFilter dllFilter(
+      [](const char16_t* aLoadedPath) -> bool {
+        nsDependentString loadedPath(aLoadedPath);
+        return StringEndsWith(loadedPath,
+                              u"\\testdllblocklist_singlenotification1.dll"_ns,
+                              nsCaseInsensitiveStringComparator) ||
+               StringEndsWith(loadedPath,
+                              u"\\testdllblocklist_singlenotification2.dll"_ns,
+                              nsCaseInsensitiveStringComparator);
+      });
+  RefPtr<TestDLLLoadObserver> obs(new TestDLLLoadObserver(dllFilter));
+  obs->Init();
+
+  // Load DllServices. This is required for notifications to get dispatched.
+  RefPtr<mozilla::DllServices> dllSvc(mozilla::DllServices::Get());
+  EXPECT_TRUE(dllSvc);
+
+  // Block-load the two DLLs multiple times on the main thread.
+  LoadSingleNotificationModules(reinterpret_cast<void*>(&dllFullPaths));
+
+  // Block-load the two DLLs multiple times on a different thread.
+  HANDLE thread =
+      ::CreateThread(nullptr, 0, LoadSingleNotificationModules,
+                     reinterpret_cast<void*>(&dllFullPaths), 0, nullptr);
+  EXPECT_EQ(::WaitForSingleObject(thread, 5000), WAIT_OBJECT_0);
+
+  // Unregister our observer and flush the main thread loop.
+  obs->Exit();
+
+  // Check how many notifications we received
+  EXPECT_EQ(obs->MainThreadNotificationsCount(), 2);
+  EXPECT_EQ(obs->NonMainThreadNotificationsCount(),
+            kSingleNotificationDll1Loads + kSingleNotificationDll2Loads);
+}
+
+#endif  // !defined(MOZ_ASAN) && !defined(_M_ARM64)
diff --git a/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_AllowByVersion/TestDllBlocklist_AllowByVersion.cpp b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_AllowByVersion/TestDllBlocklist_AllowByVersion.cpp
new file mode 100644
index 0000000000..7bd936296e
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_AllowByVersion/TestDllBlocklist_AllowByVersion.cpp
@@ -0,0 +1,7 @@
+/* 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/. */
+
+#include <windows.h>
+
+BOOL WINAPI DllMain(HINSTANCE hInstance, DWORD aReason, LPVOID) { return TRUE; }
diff --git a/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_AllowByVersion/TestDllBlocklist_AllowByVersion.rc b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_AllowByVersion/TestDllBlocklist_AllowByVersion.rc
new file mode 100644
index 0000000000..f56aa099ff
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_AllowByVersion/TestDllBlocklist_AllowByVersion.rc
@@ -0,0 +1,42 @@
+/* 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/. */
+
+#include <winver.h>
+
+/////////////////////////////////////////////////////////////////////////////
+//
+// Version
+//
+
+VS_VERSION_INFO VERSIONINFO
+  FILEVERSION    5,5,5,6
+  PRODUCTVERSION 5,5,5,1
+  FILEFLAGSMASK 0x3fL
+#ifdef _DEBUG
+  FILEFLAGS 0x1L
+#else
+  FILEFLAGS 0x0L
+#endif
+  FILEOS VOS__WINDOWS32
+  FILETYPE VFT_DLL
+  FILESUBTYPE 0x0L
+BEGIN
+  BLOCK "StringFileInfo"
+  BEGIN
+    BLOCK "040904e4"
+    BEGIN
+      VALUE "CompanyName", "mozilla.org"
+      VALUE "FileDescription", L"Test DLL"
+      VALUE "FileVersion", "1.0"
+      VALUE "InternalName", "Test DLL"
+      VALUE "OriginalFilename", "TestDllBlocklist_AllowByVersion.dll"
+      VALUE "ProductName", "Test DLL"
+      VALUE "ProductVersion", "1.0"
+    END
+  END
+  BLOCK "VarFileInfo"
+  BEGIN
+    VALUE "Translation", 0x0409, 1252
+  END
+END
diff --git a/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_AllowByVersion/moz.build b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_AllowByVersion/moz.build
new file mode 100644
index 0000000000..0987cdde1a
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_AllowByVersion/moz.build
@@ -0,0 +1,17 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# 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/.
+
+DIST_INSTALL = False
+
+SharedLibrary("TestDllBlocklist_AllowByVersion")
+
+UNIFIED_SOURCES = [
+    "TestDllBlocklist_AllowByVersion.cpp",
+]
+
+RCFILE = "TestDllBlocklist_AllowByVersion.rc"
+
+if CONFIG["COMPILE_ENVIRONMENT"]:
+    TEST_HARNESS_FILES.gtest += ["!TestDllBlocklist_AllowByVersion.dll"]
diff --git a/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_GMPluginProcessOnly/TestDllBlocklist_GMPluginProcessOnly.cpp b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_GMPluginProcessOnly/TestDllBlocklist_GMPluginProcessOnly.cpp
new file mode 100644
index 0000000000..7bd936296e
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_GMPluginProcessOnly/TestDllBlocklist_GMPluginProcessOnly.cpp
@@ -0,0 +1,7 @@
+/* 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/. */
+
+#include <windows.h>
+
+BOOL WINAPI DllMain(HINSTANCE hInstance, DWORD aReason, LPVOID) { return TRUE; }
diff --git a/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_GMPluginProcessOnly/moz.build b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_GMPluginProcessOnly/moz.build
new file mode 100644
index 0000000000..a5c89c2b8e
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_GMPluginProcessOnly/moz.build
@@ -0,0 +1,15 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# 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/.
+
+DIST_INSTALL = False
+
+SharedLibrary("TestDllBlocklist_GMPluginProcessOnly")
+
+UNIFIED_SOURCES = [
+    "TestDllBlocklist_GMPluginProcessOnly.cpp",
+]
+
+if CONFIG["COMPILE_ENVIRONMENT"]:
+    TEST_HARNESS_FILES.gtest += ["!TestDllBlocklist_GMPluginProcessOnly.dll"]
diff --git a/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_GPUProcessOnly/TestDllBlocklist_GPUProcessOnly.cpp b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_GPUProcessOnly/TestDllBlocklist_GPUProcessOnly.cpp
new file mode 100644
index 0000000000..7bd936296e
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_GPUProcessOnly/TestDllBlocklist_GPUProcessOnly.cpp
@@ -0,0 +1,7 @@
+/* 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/. */
+
+#include <windows.h>
+
+BOOL WINAPI DllMain(HINSTANCE hInstance, DWORD aReason, LPVOID) { return TRUE; }
diff --git a/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_GPUProcessOnly/moz.build b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_GPUProcessOnly/moz.build
new file mode 100644
index 0000000000..748e9cf22c
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_GPUProcessOnly/moz.build
@@ -0,0 +1,15 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# 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/.
+
+DIST_INSTALL = False
+
+SharedLibrary("TestDllBlocklist_GPUProcessOnly")
+
+UNIFIED_SOURCES = [
+    "TestDllBlocklist_GPUProcessOnly.cpp",
+]
+
+if CONFIG["COMPILE_ENVIRONMENT"]:
+    TEST_HARNESS_FILES.gtest += ["!TestDllBlocklist_GPUProcessOnly.dll"]
diff --git a/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_MatchByName/TestDllBlocklist_MatchByName.cpp b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_MatchByName/TestDllBlocklist_MatchByName.cpp
new file mode 100644
index 0000000000..7bd936296e
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_MatchByName/TestDllBlocklist_MatchByName.cpp
@@ -0,0 +1,7 @@
+/* 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/. */
+
+#include <windows.h>
+
+BOOL WINAPI DllMain(HINSTANCE hInstance, DWORD aReason, LPVOID) { return TRUE; }
diff --git a/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_MatchByName/moz.build b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_MatchByName/moz.build
new file mode 100644
index 0000000000..f34931898a
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_MatchByName/moz.build
@@ -0,0 +1,15 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# 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/.
+
+DIST_INSTALL = False
+
+SharedLibrary("TestDllBlocklist_MatchByName")
+
+UNIFIED_SOURCES = [
+    "TestDllBlocklist_MatchByName.cpp",
+]
+
+if CONFIG["COMPILE_ENVIRONMENT"]:
+    TEST_HARNESS_FILES.gtest += ["!TestDllBlocklist_MatchByName.dll"]
diff --git a/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_MatchByVersion/TestDllBlocklist_MatchByVersion.cpp b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_MatchByVersion/TestDllBlocklist_MatchByVersion.cpp
new file mode 100644
index 0000000000..7bd936296e
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_MatchByVersion/TestDllBlocklist_MatchByVersion.cpp
@@ -0,0 +1,7 @@
+/* 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/. */
+
+#include <windows.h>
+
+BOOL WINAPI DllMain(HINSTANCE hInstance, DWORD aReason, LPVOID) { return TRUE; }
diff --git a/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_MatchByVersion/TestDllBlocklist_MatchByVersion.rc b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_MatchByVersion/TestDllBlocklist_MatchByVersion.rc
new file mode 100644
index 0000000000..7390c1cb34
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_MatchByVersion/TestDllBlocklist_MatchByVersion.rc
@@ -0,0 +1,42 @@
+/* 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/. */
+
+#include <winver.h>
+
+/////////////////////////////////////////////////////////////////////////////
+//
+// Version
+//
+
+VS_VERSION_INFO VERSIONINFO
+  FILEVERSION    5,5,5,5
+  PRODUCTVERSION 5,5,5,1
+  FILEFLAGSMASK 0x3fL
+#ifdef _DEBUG
+  FILEFLAGS 0x1L
+#else
+  FILEFLAGS 0x0L
+#endif
+  FILEOS VOS__WINDOWS32
+  FILETYPE VFT_DLL
+  FILESUBTYPE 0x0L
+BEGIN
+  BLOCK "StringFileInfo"
+  BEGIN
+    BLOCK "040904e4"
+    BEGIN
+      VALUE "CompanyName", "mozilla.org"
+      VALUE "FileDescription", L"Test DLL"
+      VALUE "FileVersion", "1.0"
+      VALUE "InternalName", "Test DLL"
+      VALUE "OriginalFilename", "TestDllBlocklist_MatchByVersion.dll"
+      VALUE "ProductName", "Test DLL"
+      VALUE "ProductVersion", "1.0"
+    END
+  END
+  BLOCK "VarFileInfo"
+  BEGIN
+    VALUE "Translation", 0x0409, 1252
+  END
+END
diff --git a/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_MatchByVersion/moz.build b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_MatchByVersion/moz.build
new file mode 100644
index 0000000000..38e10524c7
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_MatchByVersion/moz.build
@@ -0,0 +1,17 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# 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/.
+
+DIST_INSTALL = False
+
+SharedLibrary("TestDllBlocklist_MatchByVersion")
+
+UNIFIED_SOURCES = [
+    "TestDllBlocklist_MatchByVersion.cpp",
+]
+
+RCFILE = "TestDllBlocklist_MatchByVersion.rc"
+
+if CONFIG["COMPILE_ENVIRONMENT"]:
+    TEST_HARNESS_FILES.gtest += ["!TestDllBlocklist_MatchByVersion.dll"]
diff --git a/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_MultipleEntries_DifferentProcesses/TestDllBlocklist_MultipleEntries_DifferentProcesses.cpp b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_MultipleEntries_DifferentProcesses/TestDllBlocklist_MultipleEntries_DifferentProcesses.cpp
new file mode 100644
index 0000000000..7bd936296e
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_MultipleEntries_DifferentProcesses/TestDllBlocklist_MultipleEntries_DifferentProcesses.cpp
@@ -0,0 +1,7 @@
+/* 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/. */
+
+#include <windows.h>
+
+BOOL WINAPI DllMain(HINSTANCE hInstance, DWORD aReason, LPVOID) { return TRUE; }
diff --git a/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_MultipleEntries_DifferentProcesses/TestDllBlocklist_MultipleEntries_DifferentProcesses.rc b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_MultipleEntries_DifferentProcesses/TestDllBlocklist_MultipleEntries_DifferentProcesses.rc
new file mode 100644
index 0000000000..2b5b81406e
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_MultipleEntries_DifferentProcesses/TestDllBlocklist_MultipleEntries_DifferentProcesses.rc
@@ -0,0 +1,42 @@
+/* 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/. */
+
+#include <winver.h>
+
+/////////////////////////////////////////////////////////////////////////////
+//
+// Version
+//
+
+VS_VERSION_INFO VERSIONINFO
+  FILEVERSION    5,5,5,5
+  PRODUCTVERSION 5,5,5,1
+  FILEFLAGSMASK 0x3fL
+#ifdef _DEBUG
+  FILEFLAGS 0x1L
+#else
+  FILEFLAGS 0x0L
+#endif
+  FILEOS VOS__WINDOWS32
+  FILETYPE VFT_DLL
+  FILESUBTYPE 0x0L
+BEGIN
+  BLOCK "StringFileInfo"
+  BEGIN
+    BLOCK "040904e4"
+    BEGIN
+      VALUE "CompanyName", "mozilla.org"
+      VALUE "FileDescription", L"Test DLL"
+      VALUE "FileVersion", "1.0"
+      VALUE "InternalName", "Test DLL"
+      VALUE "OriginalFilename", "TestDllBlocklist_MultipleEntries_DifferentProcesses.dll"
+      VALUE "ProductName", "Test DLL"
+      VALUE "ProductVersion", "1.0"
+    END
+  END
+  BLOCK "VarFileInfo"
+  BEGIN
+    VALUE "Translation", 0x0409, 1252
+  END
+END
diff --git a/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_MultipleEntries_DifferentProcesses/moz.build b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_MultipleEntries_DifferentProcesses/moz.build
new file mode 100644
index 0000000000..cf2f745a28
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_MultipleEntries_DifferentProcesses/moz.build
@@ -0,0 +1,19 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# 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/.
+
+DIST_INSTALL = False
+
+SharedLibrary("TestDllBlocklist_MultipleEntries_DifferentProcesses")
+
+UNIFIED_SOURCES = [
+    "TestDllBlocklist_MultipleEntries_DifferentProcesses.cpp",
+]
+
+RCFILE = "TestDllBlocklist_MultipleEntries_DifferentProcesses.rc"
+
+if CONFIG["COMPILE_ENVIRONMENT"]:
+    TEST_HARNESS_FILES.gtest += [
+        "!TestDllBlocklist_MultipleEntries_DifferentProcesses.dll"
+    ]
diff --git a/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_MultipleEntries_SameProcessBackward/TestDllBlocklist_MultipleEntries_SameProcessBackward.cpp b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_MultipleEntries_SameProcessBackward/TestDllBlocklist_MultipleEntries_SameProcessBackward.cpp
new file mode 100644
index 0000000000..7bd936296e
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_MultipleEntries_SameProcessBackward/TestDllBlocklist_MultipleEntries_SameProcessBackward.cpp
@@ -0,0 +1,7 @@
+/* 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/. */
+
+#include <windows.h>
+
+BOOL WINAPI DllMain(HINSTANCE hInstance, DWORD aReason, LPVOID) { return TRUE; }
diff --git a/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_MultipleEntries_SameProcessBackward/TestDllBlocklist_MultipleEntries_SameProcessBackward.rc b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_MultipleEntries_SameProcessBackward/TestDllBlocklist_MultipleEntries_SameProcessBackward.rc
new file mode 100644
index 0000000000..0b2431c343
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_MultipleEntries_SameProcessBackward/TestDllBlocklist_MultipleEntries_SameProcessBackward.rc
@@ -0,0 +1,42 @@
+/* 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/. */
+
+#include <winver.h>
+
+/////////////////////////////////////////////////////////////////////////////
+//
+// Version
+//
+
+VS_VERSION_INFO VERSIONINFO
+  FILEVERSION    5,5,5,5
+  PRODUCTVERSION 5,5,5,1
+  FILEFLAGSMASK 0x3fL
+#ifdef _DEBUG
+  FILEFLAGS 0x1L
+#else
+  FILEFLAGS 0x0L
+#endif
+  FILEOS VOS__WINDOWS32
+  FILETYPE VFT_DLL
+  FILESUBTYPE 0x0L
+BEGIN
+  BLOCK "StringFileInfo"
+  BEGIN
+    BLOCK "040904e4"
+    BEGIN
+      VALUE "CompanyName", "mozilla.org"
+      VALUE "FileDescription", L"Test DLL"
+      VALUE "FileVersion", "1.0"
+      VALUE "InternalName", "Test DLL"
+      VALUE "OriginalFilename", "TestDllBlocklist_MultipleEntries_SameProcessBackward.dll"
+      VALUE "ProductName", "Test DLL"
+      VALUE "ProductVersion", "1.0"
+    END
+  END
+  BLOCK "VarFileInfo"
+  BEGIN
+    VALUE "Translation", 0x0409, 1252
+  END
+END
diff --git a/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_MultipleEntries_SameProcessBackward/moz.build b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_MultipleEntries_SameProcessBackward/moz.build
new file mode 100644
index 0000000000..21ab229245
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_MultipleEntries_SameProcessBackward/moz.build
@@ -0,0 +1,19 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# 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/.
+
+DIST_INSTALL = False
+
+SharedLibrary("TestDllBlocklist_MultipleEntries_SameProcessBackward")
+
+UNIFIED_SOURCES = [
+    "TestDllBlocklist_MultipleEntries_SameProcessBackward.cpp",
+]
+
+RCFILE = "TestDllBlocklist_MultipleEntries_SameProcessBackward.rc"
+
+if CONFIG["COMPILE_ENVIRONMENT"]:
+    TEST_HARNESS_FILES.gtest += [
+        "!TestDllBlocklist_MultipleEntries_SameProcessBackward.dll"
+    ]
diff --git a/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_MultipleEntries_SameProcessForward/TestDllBlocklist_MultipleEntries_SameProcessForward.cpp b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_MultipleEntries_SameProcessForward/TestDllBlocklist_MultipleEntries_SameProcessForward.cpp
new file mode 100644
index 0000000000..7bd936296e
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_MultipleEntries_SameProcessForward/TestDllBlocklist_MultipleEntries_SameProcessForward.cpp
@@ -0,0 +1,7 @@
+/* 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/. */
+
+#include <windows.h>
+
+BOOL WINAPI DllMain(HINSTANCE hInstance, DWORD aReason, LPVOID) { return TRUE; }
diff --git a/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_MultipleEntries_SameProcessForward/TestDllBlocklist_MultipleEntries_SameProcessForward.rc b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_MultipleEntries_SameProcessForward/TestDllBlocklist_MultipleEntries_SameProcessForward.rc
new file mode 100644
index 0000000000..20d14e24d7
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_MultipleEntries_SameProcessForward/TestDllBlocklist_MultipleEntries_SameProcessForward.rc
@@ -0,0 +1,42 @@
+/* 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/. */
+
+#include <winver.h>
+
+/////////////////////////////////////////////////////////////////////////////
+//
+// Version
+//
+
+VS_VERSION_INFO VERSIONINFO
+  FILEVERSION    5,5,5,5
+  PRODUCTVERSION 5,5,5,1
+  FILEFLAGSMASK 0x3fL
+#ifdef _DEBUG
+  FILEFLAGS 0x1L
+#else
+  FILEFLAGS 0x0L
+#endif
+  FILEOS VOS__WINDOWS32
+  FILETYPE VFT_DLL
+  FILESUBTYPE 0x0L
+BEGIN
+  BLOCK "StringFileInfo"
+  BEGIN
+    BLOCK "040904e4"
+    BEGIN
+      VALUE "CompanyName", "mozilla.org"
+      VALUE "FileDescription", L"Test DLL"
+      VALUE "FileVersion", "1.0"
+      VALUE "InternalName", "Test DLL"
+      VALUE "OriginalFilename", "TestDllBlocklist_MultipleEntries_SameProcessForward.dll"
+      VALUE "ProductName", "Test DLL"
+      VALUE "ProductVersion", "1.0"
+    END
+  END
+  BLOCK "VarFileInfo"
+  BEGIN
+    VALUE "Translation", 0x0409, 1252
+  END
+END
diff --git a/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_MultipleEntries_SameProcessForward/moz.build b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_MultipleEntries_SameProcessForward/moz.build
new file mode 100644
index 0000000000..1546489efb
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_MultipleEntries_SameProcessForward/moz.build
@@ -0,0 +1,19 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# 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/.
+
+DIST_INSTALL = False
+
+SharedLibrary("TestDllBlocklist_MultipleEntries_SameProcessForward")
+
+UNIFIED_SOURCES = [
+    "TestDllBlocklist_MultipleEntries_SameProcessForward.cpp",
+]
+
+RCFILE = "TestDllBlocklist_MultipleEntries_SameProcessForward.rc"
+
+if CONFIG["COMPILE_ENVIRONMENT"]:
+    TEST_HARNESS_FILES.gtest += [
+        "!TestDllBlocklist_MultipleEntries_SameProcessForward.dll"
+    ]
diff --git a/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_NoOpEntryPoint/TestDllBlocklist_NoOpEntryPoint.cpp b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_NoOpEntryPoint/TestDllBlocklist_NoOpEntryPoint.cpp
new file mode 100644
index 0000000000..2505b8b700
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_NoOpEntryPoint/TestDllBlocklist_NoOpEntryPoint.cpp
@@ -0,0 +1,12 @@
+/* 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/. */
+
+#include <windows.h>
+
+#include "mozilla/Assertions.h"
+
+BOOL WINAPI DllMain(HINSTANCE hInstance, DWORD aReason, LPVOID) {
+  MOZ_RELEASE_ASSERT(0);
+  return TRUE;
+}
diff --git a/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_NoOpEntryPoint/TestDllBlocklist_NoOpEntryPoint.rc b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_NoOpEntryPoint/TestDllBlocklist_NoOpEntryPoint.rc
new file mode 100644
index 0000000000..7c79dac373
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_NoOpEntryPoint/TestDllBlocklist_NoOpEntryPoint.rc
@@ -0,0 +1,42 @@
+/* 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/. */
+
+#include <winver.h>
+
+/////////////////////////////////////////////////////////////////////////////
+//
+// Version
+//
+
+VS_VERSION_INFO VERSIONINFO
+  FILEVERSION    5,5,5,5
+  PRODUCTVERSION 5,5,5,1
+  FILEFLAGSMASK 0x3fL
+#ifdef _DEBUG
+  FILEFLAGS 0x1L
+#else
+  FILEFLAGS 0x0L
+#endif
+  FILEOS VOS__WINDOWS32
+  FILETYPE VFT_DLL
+  FILESUBTYPE 0x0L
+BEGIN
+  BLOCK "StringFileInfo"
+  BEGIN
+    BLOCK "040904e4"
+    BEGIN
+      VALUE "CompanyName", "mozilla.org"
+      VALUE "FileDescription", L"Test DLL"
+      VALUE "FileVersion", "1.0"
+      VALUE "InternalName", "Test DLL"
+      VALUE "OriginalFilename", "TestDllBlocklist_NoOpEntryPoint.dll"
+      VALUE "ProductName", "Test DLL"
+      VALUE "ProductVersion", "1.0"
+    END
+  END
+  BLOCK "VarFileInfo"
+  BEGIN
+    VALUE "Translation", 0x0409, 1252
+  END
+END
diff --git a/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_NoOpEntryPoint/moz.build b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_NoOpEntryPoint/moz.build
new file mode 100644
index 0000000000..e9a10a150a
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_NoOpEntryPoint/moz.build
@@ -0,0 +1,21 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# 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/.
+
+DIST_INSTALL = False
+
+SharedLibrary("TestDllBlocklist_NoOpEntryPoint")
+
+UNIFIED_SOURCES = [
+    "TestDllBlocklist_NoOpEntryPoint.cpp",
+]
+
+RCFILE = "TestDllBlocklist_NoOpEntryPoint.rc"
+
+if CONFIG["COMPILE_ENVIRONMENT"]:
+    TEST_HARNESS_FILES.gtest += ["!TestDllBlocklist_NoOpEntryPoint.dll"]
+
+OS_LIBS += [
+    "uuid",
+]
diff --git a/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_SingleNotification1/TestDllBlocklist_SingleNotification1.cpp b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_SingleNotification1/TestDllBlocklist_SingleNotification1.cpp
new file mode 100644
index 0000000000..4f6ce877eb
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_SingleNotification1/TestDllBlocklist_SingleNotification1.cpp
@@ -0,0 +1,7 @@
+/* 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/. */
+
+#include <windows.h>
+
+BOOL WINAPI DllMain(HINSTANCE, DWORD, LPVOID) { return TRUE; }
diff --git a/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_SingleNotification1/TestDllBlocklist_SingleNotification1.rc b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_SingleNotification1/TestDllBlocklist_SingleNotification1.rc
new file mode 100644
index 0000000000..90f098b1b9
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_SingleNotification1/TestDllBlocklist_SingleNotification1.rc
@@ -0,0 +1,42 @@
+/* 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/. */

+

+#include <winver.h>

+

+/////////////////////////////////////////////////////////////////////////////

+//

+// Version

+//

+

+VS_VERSION_INFO VERSIONINFO

+  FILEVERSION    5,5,5,5

+  PRODUCTVERSION 5,5,5,1

+  FILEFLAGSMASK 0x3fL

+#ifdef _DEBUG

+  FILEFLAGS 0x1L

+#else

+  FILEFLAGS 0x0L

+#endif

+  FILEOS VOS__WINDOWS32

+  FILETYPE VFT_DLL

+  FILESUBTYPE 0x0L

+BEGIN

+  BLOCK "StringFileInfo"

+  BEGIN

+    BLOCK "040904e4"

+    BEGIN

+      VALUE "CompanyName", "mozilla.org"

+      VALUE "FileDescription", L"Test DLL"

+      VALUE "FileVersion", "1.0"

+      VALUE "InternalName", "Test DLL"

+      VALUE "OriginalFilename", "TestDllBlocklist_SingleNotification1.dll"

+      VALUE "ProductName", "Test DLL"

+      VALUE "ProductVersion", "1.0"

+    END

+  END

+  BLOCK "VarFileInfo"

+  BEGIN

+    VALUE "Translation", 0x0409, 1252

+  END

+END

diff --git a/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_SingleNotification1/moz.build b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_SingleNotification1/moz.build
new file mode 100644
index 0000000000..79139b2b6e
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_SingleNotification1/moz.build
@@ -0,0 +1,17 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# 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/.
+
+DIST_INSTALL = False
+
+SharedLibrary("TestDllBlocklist_SingleNotification1")
+
+UNIFIED_SOURCES = [
+    "TestDllBlocklist_SingleNotification1.cpp",
+]
+
+RCFILE = "TestDllBlocklist_SingleNotification1.rc"
+
+if CONFIG["COMPILE_ENVIRONMENT"]:
+    TEST_HARNESS_FILES.gtest += ["!TestDllBlocklist_SingleNotification1.dll"]
diff --git a/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_SingleNotification2/TestDllBlocklist_SingleNotification2.cpp b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_SingleNotification2/TestDllBlocklist_SingleNotification2.cpp
new file mode 100644
index 0000000000..4f6ce877eb
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_SingleNotification2/TestDllBlocklist_SingleNotification2.cpp
@@ -0,0 +1,7 @@
+/* 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/. */
+
+#include <windows.h>
+
+BOOL WINAPI DllMain(HINSTANCE, DWORD, LPVOID) { return TRUE; }
diff --git a/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_SingleNotification2/TestDllBlocklist_SingleNotification2.rc b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_SingleNotification2/TestDllBlocklist_SingleNotification2.rc
new file mode 100644
index 0000000000..0cd44b2f9b
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_SingleNotification2/TestDllBlocklist_SingleNotification2.rc
@@ -0,0 +1,42 @@
+/* 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/. */

+

+#include <winver.h>

+

+/////////////////////////////////////////////////////////////////////////////

+//

+// Version

+//

+

+VS_VERSION_INFO VERSIONINFO

+  FILEVERSION    5,5,5,5

+  PRODUCTVERSION 5,5,5,1

+  FILEFLAGSMASK 0x3fL

+#ifdef _DEBUG

+  FILEFLAGS 0x1L

+#else

+  FILEFLAGS 0x0L

+#endif

+  FILEOS VOS__WINDOWS32

+  FILETYPE VFT_DLL

+  FILESUBTYPE 0x0L

+BEGIN

+  BLOCK "StringFileInfo"

+  BEGIN

+    BLOCK "040904e4"

+    BEGIN

+      VALUE "CompanyName", "mozilla.org"

+      VALUE "FileDescription", L"Test DLL"

+      VALUE "FileVersion", "1.0"

+      VALUE "InternalName", "Test DLL"

+      VALUE "OriginalFilename", "TestDllBlocklist_SingleNotification2.dll"

+      VALUE "ProductName", "Test DLL"

+      VALUE "ProductVersion", "1.0"

+    END

+  END

+  BLOCK "VarFileInfo"

+  BEGIN

+    VALUE "Translation", 0x0409, 1252

+  END

+END

diff --git a/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_SingleNotification2/moz.build b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_SingleNotification2/moz.build
new file mode 100644
index 0000000000..64d551f480
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_SingleNotification2/moz.build
@@ -0,0 +1,17 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# 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/.
+
+DIST_INSTALL = False
+
+SharedLibrary("TestDllBlocklist_SingleNotification2")
+
+UNIFIED_SOURCES = [
+    "TestDllBlocklist_SingleNotification2.cpp",
+]
+
+RCFILE = "TestDllBlocklist_SingleNotification2.rc"
+
+if CONFIG["COMPILE_ENVIRONMENT"]:
+    TEST_HARNESS_FILES.gtest += ["!TestDllBlocklist_SingleNotification2.dll"]
diff --git a/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_SocketProcessOnly/TestDllBlocklist_SocketProcessOnly.cpp b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_SocketProcessOnly/TestDllBlocklist_SocketProcessOnly.cpp
new file mode 100644
index 0000000000..7bd936296e
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_SocketProcessOnly/TestDllBlocklist_SocketProcessOnly.cpp
@@ -0,0 +1,7 @@
+/* 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/. */
+
+#include <windows.h>
+
+BOOL WINAPI DllMain(HINSTANCE hInstance, DWORD aReason, LPVOID) { return TRUE; }
diff --git a/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_SocketProcessOnly/moz.build b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_SocketProcessOnly/moz.build
new file mode 100644
index 0000000000..dc93544e1b
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_SocketProcessOnly/moz.build
@@ -0,0 +1,15 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# 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/.
+
+DIST_INSTALL = False
+
+SharedLibrary("TestDllBlocklist_SocketProcessOnly")
+
+UNIFIED_SOURCES = [
+    "TestDllBlocklist_SocketProcessOnly.cpp",
+]
+
+if CONFIG["COMPILE_ENVIRONMENT"]:
+    TEST_HARNESS_FILES.gtest += ["!TestDllBlocklist_SocketProcessOnly.dll"]
diff --git a/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_UserBlocked/TestDllBlocklist_UserBlocked.cpp b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_UserBlocked/TestDllBlocklist_UserBlocked.cpp
new file mode 100644
index 0000000000..7bd936296e
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_UserBlocked/TestDllBlocklist_UserBlocked.cpp
@@ -0,0 +1,7 @@
+/* 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/. */
+
+#include <windows.h>
+
+BOOL WINAPI DllMain(HINSTANCE hInstance, DWORD aReason, LPVOID) { return TRUE; }
diff --git a/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_UserBlocked/moz.build b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_UserBlocked/moz.build
new file mode 100644
index 0000000000..31996c5cb2
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_UserBlocked/moz.build
@@ -0,0 +1,15 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# 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/.
+
+DIST_INSTALL = False
+
+SharedLibrary("TestDllBlocklist_UserBlocked")
+
+UNIFIED_SOURCES = [
+    "TestDllBlocklist_UserBlocked.cpp",
+]
+
+if CONFIG["COMPILE_ENVIRONMENT"]:
+    TEST_HARNESS_FILES.gtest += ["!TestDllBlocklist_UserBlocked.dll"]
diff --git a/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_UtilityProcessOnly/TestDllBlocklist_UtilityProcessOnly.cpp b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_UtilityProcessOnly/TestDllBlocklist_UtilityProcessOnly.cpp
new file mode 100644
index 0000000000..7bd936296e
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_UtilityProcessOnly/TestDllBlocklist_UtilityProcessOnly.cpp
@@ -0,0 +1,7 @@
+/* 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/. */
+
+#include <windows.h>
+
+BOOL WINAPI DllMain(HINSTANCE hInstance, DWORD aReason, LPVOID) { return TRUE; }
diff --git a/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_UtilityProcessOnly/moz.build b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_UtilityProcessOnly/moz.build
new file mode 100644
index 0000000000..913d0f155c
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/TestDllBlocklist_UtilityProcessOnly/moz.build
@@ -0,0 +1,15 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# 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/.
+
+DIST_INSTALL = False
+
+SharedLibrary("TestDllBlocklist_UtilityProcessOnly")
+
+UNIFIED_SOURCES = [
+    "TestDllBlocklist_UtilityProcessOnly.cpp",
+]
+
+if CONFIG["COMPILE_ENVIRONMENT"]:
+    TEST_HARNESS_FILES.gtest += ["!TestDllBlocklist_UtilityProcessOnly.dll"]
diff --git a/toolkit/xre/dllservices/tests/gtest/TestUntrustedModules.cpp b/toolkit/xre/dllservices/tests/gtest/TestUntrustedModules.cpp
new file mode 100644
index 0000000000..ba4d1a8df8
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/TestUntrustedModules.cpp
@@ -0,0 +1,462 @@
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+#include "gtest/gtest.h"
+
+#include "js/RegExp.h"
+#include "mozilla/BinarySearch.h"
+#include "mozilla/gtest/MozAssertions.h"
+#include "mozilla/SpinEventLoopUntil.h"
+#include "mozilla/UntrustedModulesProcessor.h"
+#include "mozilla/WinDllServices.h"
+#include "nsContentUtils.h"
+#include "nsDirectoryServiceDefs.h"
+#include "TelemetryFixture.h"
+#include "UntrustedModulesBackupService.h"
+#include "UntrustedModulesDataSerializer.h"
+
+using namespace mozilla;
+
+class ModuleLoadCounter final {
+  nsTHashMap<nsStringCaseInsensitiveHashKey, int> mCounters;
+
+ public:
+  template <size_t N>
+  ModuleLoadCounter(const nsString (&aNames)[N], const int (&aCounts)[N])
+      : mCounters(N) {
+    for (size_t i = 0; i < N; ++i) {
+      mCounters.InsertOrUpdate(aNames[i], aCounts[i]);
+    }
+  }
+
+  template <size_t N>
+  bool Remains(const nsString (&aNames)[N], const int (&aCounts)[N]) {
+    EXPECT_EQ(mCounters.Count(), N);
+    if (mCounters.Count() != N) {
+      return false;
+    }
+
+    bool result = true;
+    for (size_t i = 0; i < N; ++i) {
+      auto entry = mCounters.Lookup(aNames[i]);
+      if (!entry) {
+        wprintf(L"%s is not registered.\n",
+                static_cast<const wchar_t*>(aNames[i].get()));
+        result = false;
+      } else if (*entry != aCounts[i]) {
+        // We can return false, but let's print out all unmet modules
+        // which may be helpful to investigate test failures.
+        wprintf(L"%s:%4d\n", static_cast<const wchar_t*>(aNames[i].get()),
+                *entry);
+        result = false;
+      }
+    }
+    return result;
+  }
+
+  bool IsDone() const {
+    bool allZero = true;
+    for (const auto& data : mCounters.Values()) {
+      if (data < 0) {
+        // If any counter is negative, we know the test fails.
+        // No need to continue.
+        return true;
+      }
+      if (data > 0) {
+        allZero = false;
+      }
+    }
+    // If all counters are zero, the test finished nicely.  Otherwise, those
+    // counters are expected to be decremented later.  Let's continue.
+    return allZero;
+  }
+
+  void Decrement(const nsString& aName) {
+    if (auto entry = mCounters.Lookup(aName)) {
+      --(*entry);
+    }
+  }
+};
+
+class UntrustedModulesCollector {
+  static constexpr int kMaximumAttempts = 500;
+  Vector<UntrustedModulesData> mData;
+  ModuleLoadCounter* mChecker = nullptr;
+  Maybe<nsresult> mRv;
+  int mAttempts = 0;
+
+  void PollUntrustedModulesData() {
+    RefPtr<DllServices> dllSvc(DllServices::Get());
+    dllSvc->GetUntrustedModulesData()->Then(
+        GetMainThreadSerialEventTarget(), __func__,
+        [this](Maybe<UntrustedModulesData>&& aResult) {
+          // Some of expected loaded modules are still missing after
+          // kMaximumAttempts queries were submitted.
+          // Giving up here to avoid an infinite loop.
+          if (++mAttempts > kMaximumAttempts) {
+            mRv = Some(NS_ERROR_ABORT);
+            return;
+          }
+
+          if (aResult.isSome()) {
+            wprintf(L"Received data. (attempts=%d)\n", mAttempts);
+            for (auto item : aResult.ref().mEvents) {
+              mChecker->Decrement(item->mEvent.mRequestedDllName);
+            }
+            EXPECT_TRUE(mData.emplaceBack(std::move(aResult.ref())));
+          }
+
+          if (mChecker->IsDone()) {
+            mRv = Some(NS_OK);
+            return;
+          }
+
+          PollUntrustedModulesData();
+        },
+        [this](nsresult aReason) {
+          wprintf(L"GetUntrustedModulesData() failed - %08x\n", aReason);
+          EXPECT_TRUE(false);
+          mRv = Some(aReason);
+        });
+  }
+
+ public:
+  Vector<UntrustedModulesData>& Data() { return mData; }
+
+  nsresult Collect(ModuleLoadCounter& aChecker) {
+    mRv = Nothing();
+    mChecker = &aChecker;
+    mAttempts = 0;
+    mData.clear();
+
+    PollUntrustedModulesData();
+
+    EXPECT_TRUE(SpinEventLoopUntil("xre:UntrustedModulesCollector"_ns,
+                                   [this]() { return mRv.isSome(); }));
+
+    mChecker = nullptr;
+    return *mRv;
+  }
+};
+
+class UntrustedModulesFixture : public TelemetryTestFixture {
+  static constexpr int kLoadCountBeforeDllServices = 5;
+  static constexpr int kLoadCountAfterDllServices = 5;
+  static constexpr uint32_t kMaxModulesArrayLen = 10;
+
+  // One of the important test scenarios is to load modules before DllServices
+  // is initialized and to make sure those loading events are forwarded when
+  // DllServices is initialized.
+  // However, GTest instantiates a Fixture class every testcase and there is
+  // no way to re-enable DllServices and UntrustedModulesProcessor once it's
+  // disabled, which means no matter how many testcases we have, only the
+  // first testcase exercises that scenario.  That's why we implement that
+  // test scenario in InitialModuleLoadOnce as a static member and runs it
+  // in the first testcase to be executed.
+  static INIT_ONCE sInitLoadOnce;
+  static UntrustedModulesCollector sInitLoadDataCollector;
+
+  static nsString PrependWorkingDir(const nsAString& aLeaf) {
+    nsCOMPtr<nsIFile> file;
+    EXPECT_TRUE(NS_SUCCEEDED(NS_GetSpecialDirectory(NS_OS_CURRENT_WORKING_DIR,
+                                                    getter_AddRefs(file))));
+    EXPECT_NS_SUCCEEDED(file->Append(aLeaf));
+    bool exists;
+    EXPECT_TRUE(NS_SUCCEEDED(file->Exists(&exists)) && exists);
+    nsString fullPath;
+    EXPECT_NS_SUCCEEDED(file->GetPath(fullPath));
+    return fullPath;
+  }
+
+  static BOOL CALLBACK InitialModuleLoadOnce(PINIT_ONCE, void*, void**);
+
+ protected:
+  static constexpr int kInitLoadCount =
+      kLoadCountBeforeDllServices + kLoadCountAfterDllServices;
+  static const nsString kTestModules[];
+
+  static void ValidateUntrustedModules(const UntrustedModulesData& aData,
+                                       bool aIsTruncatedData = false);
+
+  static void LoadAndFree(const nsAString& aLeaf) {
+    nsModuleHandle dll(::LoadLibraryW(PrependWorkingDir(aLeaf).get()));
+    EXPECT_TRUE(!!dll);
+  }
+
+  virtual void SetUp() override {
+    TelemetryTestFixture::SetUp();
+    ::InitOnceExecuteOnce(&sInitLoadOnce, InitialModuleLoadOnce, nullptr,
+                          nullptr);
+  }
+
+  static const Vector<UntrustedModulesData>& GetInitLoadData() {
+    return sInitLoadDataCollector.Data();
+  }
+
+  // This method is useful if we want a new instance of UntrustedModulesData
+  // which is not copyable.
+  static UntrustedModulesData CollectSingleData() {
+    // If we call LoadAndFree more than once, those loading events are
+    // likely to be merged into an instance of UntrustedModulesData,
+    // meaning the length of the collector's vector is at least one but
+    // the exact number is unknown.
+    LoadAndFree(kTestModules[0]);
+
+    UntrustedModulesCollector collector;
+    ModuleLoadCounter waitForOne({kTestModules[0]}, {1});
+    EXPECT_NS_SUCCEEDED(collector.Collect(waitForOne));
+    EXPECT_TRUE(waitForOne.Remains({kTestModules[0]}, {0}));
+    EXPECT_EQ(collector.Data().length(), 1U);
+
+    // Cannot "return collector.Data()[0]" as copy ctor is deleted.
+    return UntrustedModulesData(std::move(collector.Data()[0]));
+  }
+
+  template <typename DataFetcherT>
+  void ValidateJSValue(const char16_t* aPattern, size_t aPatternLength,
+                       DataFetcherT&& aDataFetcher) {
+    AutoJSContextWithGlobal cx(mCleanGlobal);
+    mozilla::Telemetry::UntrustedModulesDataSerializer serializer(
+        cx.GetJSContext(), kMaxModulesArrayLen);
+    EXPECT_TRUE(!!serializer);
+    aDataFetcher(serializer);
+
+    JS::Rooted<JS::Value> jsval(cx.GetJSContext());
+    serializer.GetObject(&jsval);
+
+    nsAutoString json;
+    EXPECT_TRUE(nsContentUtils::StringifyJSON(
+        cx.GetJSContext(), jsval, json, dom::UndefinedIsNullStringLiteral));
+
+    JS::Rooted<JSObject*> re(
+        cx.GetJSContext(),
+        JS::NewUCRegExpObject(cx.GetJSContext(), aPattern, aPatternLength,
+                              JS::RegExpFlag::Global));
+    EXPECT_TRUE(!!re);
+
+    JS::Rooted<JS::Value> matchResult(cx.GetJSContext(), JS::NullValue());
+    size_t idx = 0;
+    EXPECT_TRUE(JS::ExecuteRegExpNoStatics(cx.GetJSContext(), re, json.get(),
+                                           json.Length(), &idx, true,
+                                           &matchResult));
+    // On match, with aOnlyMatch = true, ExecuteRegExpNoStatics returns boolean
+    // true.  If no match, ExecuteRegExpNoStatics returns Null.
+    EXPECT_TRUE(matchResult.isBoolean() && matchResult.toBoolean());
+    if (!matchResult.isBoolean() || !matchResult.toBoolean()) {
+      // If match failed, print out the actual JSON kindly.
+      wprintf(L"JSON: %s\n", static_cast<const wchar_t*>(json.get()));
+      wprintf(L"RE: %s\n", aPattern);
+    }
+  }
+};
+
+const nsString UntrustedModulesFixture::kTestModules[] = {
+    // Sorted for binary-search
+    u"TestUntrustedModules_Dll1.dll"_ns,
+    u"TestUntrustedModules_Dll2.dll"_ns,
+};
+
+INIT_ONCE UntrustedModulesFixture::sInitLoadOnce = INIT_ONCE_STATIC_INIT;
+UntrustedModulesCollector UntrustedModulesFixture::sInitLoadDataCollector;
+
+void UntrustedModulesFixture::ValidateUntrustedModules(
+    const UntrustedModulesData& aData, bool aIsTruncatedData) {
+  // This defines a list of modules which are listed on our blocklist and
+  // thus its loading status is not expected to be Status::Loaded.
+  // Although the UntrustedModulesFixture test does not touch any of them,
+  // the current process might have run a test like TestDllBlocklist where
+  // we try to load and block them.
+  const struct {
+    const wchar_t* mName;
+    ModuleLoadInfo::Status mStatus;
+  } kKnownModules[] = {
+    // Sorted by mName for binary-search
+    {L"TestDllBlocklist_MatchByName.dll", ModuleLoadInfo::Status::Blocked},
+    {L"TestDllBlocklist_MatchByVersion.dll", ModuleLoadInfo::Status::Blocked},
+    {L"TestDllBlocklist_NoOpEntryPoint.dll",
+     ModuleLoadInfo::Status::Redirected},
+#if !defined(MOZ_ASAN)
+    // With ASAN, the test uses mozglue's blocklist where
+    // the user blocklist is not used. So only check for this
+    // DLL in the non-ASAN case.
+    {L"TestDllBlocklist_UserBlocked.dll", ModuleLoadInfo::Status::Blocked},
+#endif  // !defined(MOZ_ASAN)
+  };
+
+  EXPECT_EQ(aData.mProcessType, GeckoProcessType_Default);
+  EXPECT_EQ(aData.mPid, ::GetCurrentProcessId());
+
+  nsTHashtable<nsPtrHashKey<void>> moduleSet;
+  for (const RefPtr<ModuleRecord>& module : aData.mModules.Values()) {
+    moduleSet.PutEntry(module);
+  }
+
+  size_t numBlockedEvents = 0;
+  for (auto item : aData.mEvents) {
+    const auto& evt = item->mEvent;
+    const nsDependentSubstring leafName =
+        nt::GetLeafName(evt.mModule->mResolvedNtName);
+    const nsAutoString leafNameStr(leafName.Data(), leafName.Length());
+    const ModuleLoadInfo::Status loadStatus =
+        static_cast<ModuleLoadInfo::Status>(evt.mLoadStatus);
+    if (loadStatus == ModuleLoadInfo::Status::Blocked) {
+      ++numBlockedEvents;
+    }
+
+    size_t match;
+    if (BinarySearchIf(
+            kKnownModules, 0, ArrayLength(kKnownModules),
+            [&leafNameStr](const auto& aVal) {
+              return _wcsicmp(leafNameStr.get(), aVal.mName);
+            },
+            &match)) {
+      EXPECT_EQ(loadStatus, kKnownModules[match].mStatus);
+    } else {
+      EXPECT_EQ(evt.mLoadStatus, 0U);
+    }
+
+    if (BinarySearchIf(
+            kTestModules, 0, ArrayLength(kTestModules),
+            [&leafNameStr](const auto& aVal) {
+              return _wcsicmp(leafNameStr.get(), aVal.get());
+            },
+            &match)) {
+      // We know the test modules are loaded in the main thread,
+      // but we don't know about other modules.
+      EXPECT_EQ(evt.mThreadId, ::GetCurrentThreadId());
+    }
+
+    // Make sure mModule is pointing to an entry of mModules.
+    EXPECT_TRUE(moduleSet.Contains(evt.mModule));
+    EXPECT_FALSE(evt.mIsDependent);
+  }
+
+  // No check for the mXULLoadDurationMS field because the field has a value
+  // in CCov build GTest, but it is empty in non-CCov build (bug 1681936).
+  EXPECT_EQ(aData.mNumEvents, aData.mEvents.length());
+  EXPECT_GT(aData.mNumEvents, 0U);
+  if (aIsTruncatedData) {
+    EXPECT_EQ(aData.mStacks.GetModuleCount(), 0U);
+    EXPECT_LE(aData.mNumEvents, UntrustedModulesData::kMaxEvents);
+  } else if (numBlockedEvents == aData.mNumEvents) {
+    // If all loading events were blocked or aData is truncated,
+    // the stacks are empty.
+    EXPECT_EQ(aData.mStacks.GetModuleCount(), 0U);
+  } else {
+    EXPECT_GT(aData.mStacks.GetModuleCount(), 0U);
+  }
+  EXPECT_EQ(aData.mSanitizationFailures, 0U);
+  EXPECT_EQ(aData.mTrustTestFailures, 0U);
+}
+
+BOOL CALLBACK UntrustedModulesFixture::InitialModuleLoadOnce(PINIT_ONCE, void*,
+                                                             void**) {
+  for (int i = 0; i < kLoadCountBeforeDllServices; ++i) {
+    for (const auto& mod : kTestModules) {
+      LoadAndFree(mod);
+    }
+  }
+
+  RefPtr<DllServices> dllSvc(DllServices::Get());
+  dllSvc->StartUntrustedModulesProcessor(true);
+
+  for (int i = 0; i < kLoadCountAfterDllServices; ++i) {
+    for (const auto& mod : kTestModules) {
+      LoadAndFree(mod);
+    }
+  }
+
+  ModuleLoadCounter waitForTwo(kTestModules, {kInitLoadCount, kInitLoadCount});
+  EXPECT_EQ(sInitLoadDataCollector.Collect(waitForTwo), NS_OK);
+  EXPECT_TRUE(waitForTwo.Remains(kTestModules, {0, 0}));
+
+  for (const auto& event : GetInitLoadData()) {
+    ValidateUntrustedModules(event);
+  }
+
+  // Data was removed when retrieved.  No data is retrieved again.
+  UntrustedModulesCollector collector;
+  ModuleLoadCounter waitOnceForEach(kTestModules, {1, 1});
+  EXPECT_EQ(collector.Collect(waitOnceForEach), NS_ERROR_ABORT);
+  EXPECT_TRUE(waitOnceForEach.Remains(kTestModules, {1, 1}));
+
+  return TRUE;
+}
+
+#define PROCESS_OBJ(TYPE, PID) \
+  u"\"" TYPE u"\\." PID u"\":{" \
+    u"\"processType\":\"" TYPE u"\",\"elapsed\":\\d+\\.\\d+," \
+    u"\"sanitizationFailures\":0,\"trustTestFailures\":0," \
+    u"\"events\":\\[{" \
+      u"\"processUptimeMS\":\\d+,\"loadDurationMS\":\\d+\\.\\d+," \
+      u"\"threadID\":\\d+,\"threadName\":\"Main Thread\"," \
+      u"\"baseAddress\":\"0x[0-9a-f]+\",\"moduleIndex\":0," \
+      u"\"isDependent\":false,\"loadStatus\":0}\\]," \
+    u"\"combinedStacks\":{" \
+      u"\"memoryMap\":\\[\\[\"\\w+\\.\\w+\",\"[0-9A-Z]+\"\\]" \
+        u"(,\\[\"\\w+\\.\\w+\",\"[0-9A-Z]+\\\"\\])*\\]," \
+      u"\"stacks\":\\[\\[\\[(-1|\\d+),\\d+\\]" \
+        u"(,\\[(-1|\\d+),\\d+\\])*\\]\\]}}"
+
+TEST_F(UntrustedModulesFixture, Serialize) {
+  // clang-format off
+  const char16_t kPattern[] = u"{\"structVersion\":1,"
+    u"\"modules\":\\[{"
+      u"\"resolvedDllName\":\"TestUntrustedModules_Dll1\\.dll\","
+      u"\"fileVersion\":\"1\\.2\\.3\\.4\","
+      // It would be nice to hard-code this, but this might change with
+      // compiler versions, etc.
+      u"\"debugID\":\"[0-9A-F]{33}\","
+      u"\"companyName\":\"Mozilla Corporation\",\"trustFlags\":0}\\],"
+    u"\"blockedModules\":\\[.*?\\]," // allow for the case where there are some blocked modules
+    u"\"processes\":{"
+      PROCESS_OBJ(u"browser", u"0xabc") u","
+      PROCESS_OBJ(u"browser", u"0x4") u","
+      PROCESS_OBJ(u"rdd", u"0x4")
+  u"}}";
+  // clang-format on
+
+  UntrustedModulesBackupData backup1, backup2;
+  {
+    UntrustedModulesData data1 = CollectSingleData();
+    UntrustedModulesData data2 = CollectSingleData();
+    UntrustedModulesData data3 = CollectSingleData();
+
+    data1.mPid = 0xabc;
+    data2.mPid = 0x4;
+    data2.mProcessType = GeckoProcessType_RDD;
+    data3.mPid = 0x4;
+
+    backup1.Add(std::move(data1));
+    backup2.Add(std::move(data2));
+    backup1.Add(std::move(data3));
+  }
+
+  ValidateJSValue(kPattern, ArrayLength(kPattern) - 1,
+                  [&backup1, &backup2](
+                      Telemetry::UntrustedModulesDataSerializer& aSerializer) {
+                    EXPECT_NS_SUCCEEDED(aSerializer.Add(backup1));
+                    EXPECT_NS_SUCCEEDED(aSerializer.Add(backup2));
+                  });
+}
+
+TEST_F(UntrustedModulesFixture, Backup) {
+  RefPtr<UntrustedModulesBackupService> backupSvc(
+      UntrustedModulesBackupService::Get());
+  for (int i = 0; i < 100; ++i) {
+    backupSvc->Backup(CollectSingleData());
+  }
+
+  backupSvc->SettleAllStagingData();
+  EXPECT_TRUE(backupSvc->Staging().IsEmpty());
+
+  for (const auto& entry : backupSvc->Settled()) {
+    const RefPtr<UntrustedModulesDataContainer>& container = entry.GetData();
+    EXPECT_TRUE(!!container);
+    const UntrustedModulesData& data = container->mData;
+    EXPECT_EQ(entry.GetKey(), ProcessHashKey(data.mProcessType, data.mPid));
+    ValidateUntrustedModules(data, /*aIsTruncatedData*/ true);
+  }
+}
diff --git a/toolkit/xre/dllservices/tests/gtest/TestUntrustedModules_Dll1/TestUntrustedModules_Dll1.cpp b/toolkit/xre/dllservices/tests/gtest/TestUntrustedModules_Dll1/TestUntrustedModules_Dll1.cpp
new file mode 100644
index 0000000000..4f6ce877eb
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/TestUntrustedModules_Dll1/TestUntrustedModules_Dll1.cpp
@@ -0,0 +1,7 @@
+/* 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/. */
+
+#include <windows.h>
+
+BOOL WINAPI DllMain(HINSTANCE, DWORD, LPVOID) { return TRUE; }
diff --git a/toolkit/xre/dllservices/tests/gtest/TestUntrustedModules_Dll1/TestUntrustedModules_Dll1.rc b/toolkit/xre/dllservices/tests/gtest/TestUntrustedModules_Dll1/TestUntrustedModules_Dll1.rc
new file mode 100644
index 0000000000..2358b88b93
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/TestUntrustedModules_Dll1/TestUntrustedModules_Dll1.rc
@@ -0,0 +1,38 @@
+/* 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/. */

+

+#include <winver.h>

+

+/////////////////////////////////////////////////////////////////////////////

+//

+// Version

+//

+

+VS_VERSION_INFO VERSIONINFO

+  FILEVERSION    1,2,3,4  // This field will be collected

+  PRODUCTVERSION 5,6,7,8

+  FILEFLAGSMASK 0x3fL

+#ifdef _DEBUG

+  FILEFLAGS 0x1L

+#else

+  FILEFLAGS 0x0L

+#endif

+  FILEOS VOS__WINDOWS32

+  FILETYPE VFT_DLL

+  FILESUBTYPE 0x0L

+BEGIN

+  BLOCK "StringFileInfo"

+  BEGIN

+    BLOCK "040904e4"

+    BEGIN

+      VALUE "CompanyName", "Mozilla Corporation"

+      VALUE "OriginalFilename", "TestUntrustedModules_Dll1.dll"

+      VALUE "ProductName", "Test DLL"

+    END

+  END

+  BLOCK "VarFileInfo"

+  BEGIN

+    VALUE "Translation", 0x0409, 1252

+  END

+END

diff --git a/toolkit/xre/dllservices/tests/gtest/TestUntrustedModules_Dll1/moz.build b/toolkit/xre/dllservices/tests/gtest/TestUntrustedModules_Dll1/moz.build
new file mode 100644
index 0000000000..57fc59ca8a
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/TestUntrustedModules_Dll1/moz.build
@@ -0,0 +1,17 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# 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/.
+
+DIST_INSTALL = False
+
+SharedLibrary("TestUntrustedModules_Dll1")
+
+UNIFIED_SOURCES = [
+    "TestUntrustedModules_Dll1.cpp",
+]
+
+RCFILE = "TestUntrustedModules_Dll1.rc"
+
+if CONFIG["COMPILE_ENVIRONMENT"]:
+    TEST_HARNESS_FILES.gtest += ["!TestUntrustedModules_Dll1.dll"]
diff --git a/toolkit/xre/dllservices/tests/gtest/TestUntrustedModules_Dll2/TestUntrustedModules_Dll2.cpp b/toolkit/xre/dllservices/tests/gtest/TestUntrustedModules_Dll2/TestUntrustedModules_Dll2.cpp
new file mode 100644
index 0000000000..4f6ce877eb
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/TestUntrustedModules_Dll2/TestUntrustedModules_Dll2.cpp
@@ -0,0 +1,7 @@
+/* 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/. */
+
+#include <windows.h>
+
+BOOL WINAPI DllMain(HINSTANCE, DWORD, LPVOID) { return TRUE; }
diff --git a/toolkit/xre/dllservices/tests/gtest/TestUntrustedModules_Dll2/moz.build b/toolkit/xre/dllservices/tests/gtest/TestUntrustedModules_Dll2/moz.build
new file mode 100644
index 0000000000..fcefe41329
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/TestUntrustedModules_Dll2/moz.build
@@ -0,0 +1,15 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# 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/.
+
+DIST_INSTALL = False
+
+SharedLibrary("TestUntrustedModules_Dll2")
+
+UNIFIED_SOURCES = [
+    "TestUntrustedModules_Dll2.cpp",
+]
+
+if CONFIG["COMPILE_ENVIRONMENT"]:
+    TEST_HARNESS_FILES.gtest += ["!TestUntrustedModules_Dll2.dll"]
diff --git a/toolkit/xre/dllservices/tests/gtest/moz.build b/toolkit/xre/dllservices/tests/gtest/moz.build
new file mode 100644
index 0000000000..92f341841a
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/moz.build
@@ -0,0 +1,39 @@
+# 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/.
+
+Library("dllservicestest")
+
+UNIFIED_SOURCES += [
+    "TestDLLBlocklist.cpp",
+    "TestUntrustedModules.cpp",
+]
+
+LOCAL_INCLUDES += [
+    "/toolkit/components/telemetry/other",
+    "/toolkit/components/telemetry/tests/gtest",
+]
+
+TEST_DIRS += [
+    "rust",
+    "TestDllBlocklist_AllowByVersion",
+    "TestDllBlocklist_GMPluginProcessOnly",
+    "TestDllBlocklist_GPUProcessOnly",
+    "TestDllBlocklist_MatchByName",
+    "TestDllBlocklist_MatchByVersion",
+    "TestDllBlocklist_MultipleEntries_DifferentProcesses",
+    "TestDllBlocklist_MultipleEntries_SameProcessBackward",
+    "TestDllBlocklist_MultipleEntries_SameProcessForward",
+    "TestDllBlocklist_NoOpEntryPoint",
+    "TestDllBlocklist_SingleNotification1",
+    "TestDllBlocklist_SingleNotification2",
+    "TestDllBlocklist_SocketProcessOnly",
+    "TestDllBlocklist_UserBlocked",
+    "TestDllBlocklist_UtilityProcessOnly",
+    "TestUntrustedModules_Dll1",
+    "TestUntrustedModules_Dll2",
+]
+
+include("/ipc/chromium/chromium-config.mozbuild")
+
+FINAL_LIBRARY = "xul-gtest"
diff --git a/toolkit/xre/dllservices/tests/gtest/rust/Cargo.toml b/toolkit/xre/dllservices/tests/gtest/rust/Cargo.toml
new file mode 100644
index 0000000000..a342fb8bf2
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/rust/Cargo.toml
@@ -0,0 +1,12 @@
+[package]

+name = "dllservices-gtest"

+version = "0.1.0"

+authors = ["nobody@mozilla.com"]

+license = "MPL-2.0"

+description = "Tests for dllservices"

+

+[dependencies]

+uuid = { version = "1.0", features = ["v4"] }

+

+[lib]

+path = "test.rs"

diff --git a/toolkit/xre/dllservices/tests/gtest/rust/TestBCryptFallback.cpp b/toolkit/xre/dllservices/tests/gtest/rust/TestBCryptFallback.cpp
new file mode 100644
index 0000000000..ca4dbde3ab
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/rust/TestBCryptFallback.cpp
@@ -0,0 +1,113 @@
+/* -*- 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/. */
+
+#include <windows.h>
+#include <ntstatus.h>
+
+#include <bcrypt.h>
+#pragma comment(lib, "bcrypt.lib")
+
+#include "gtest/gtest.h"
+
+#include "nsWindowsDllInterceptor.h"
+
+#define RtlGenRandom SystemFunction036
+extern "C" BOOLEAN NTAPI RtlGenRandom(PVOID aRandomBuffer,
+                                      ULONG aRandomBufferLength);
+
+static mozilla::WindowsDllInterceptor BCryptIntercept;
+static mozilla::WindowsDllInterceptor::FuncHookType<
+    decltype(&::BCryptGenRandom)>
+    stub_BCryptGenRandom;
+
+static mozilla::WindowsDllInterceptor AdvApiIntercept;
+static mozilla::WindowsDllInterceptor::FuncHookType<decltype(&RtlGenRandom)>
+    stub_RtlGenRandom;
+
+volatile bool gAreHooksActive = false;
+volatile bool gHasPanicked = false;
+volatile bool gHasReachedBCryptGenRandom = false;
+volatile bool gHasReachedRtlGenRandom = false;
+
+NTSTATUS WINAPI patched_BCryptGenRandom(BCRYPT_ALG_HANDLE aAlgorithm,
+                                        PUCHAR aBuffer, ULONG aSize,
+                                        ULONG aFlags) {
+  if (gAreHooksActive) {
+    gHasReachedBCryptGenRandom = true;
+    // Force BCryptGenRandom failures when the hook is active.
+    return STATUS_UNSUCCESSFUL;
+  }
+  return stub_BCryptGenRandom(aAlgorithm, aBuffer, aSize, aFlags);
+}
+
+BOOLEAN NTAPI patched_RtlGenRandom(PVOID aRandomBuffer,
+                                   ULONG aRandomBufferLength) {
+  if (gAreHooksActive) {
+    gHasReachedRtlGenRandom = true;
+  }
+  return stub_RtlGenRandom(aRandomBuffer, aRandomBufferLength);
+}
+
+bool InitInterception() {
+  static bool sSuccess = []() {
+    BCryptIntercept.Init(L"bcrypt.dll");
+    AdvApiIntercept.Init(L"advapi32.dll");
+    return stub_BCryptGenRandom.SetDetour(BCryptIntercept, "BCryptGenRandom",
+                                          patched_BCryptGenRandom) &&
+           stub_RtlGenRandom.SetDetour(AdvApiIntercept, "SystemFunction036",
+                                       patched_RtlGenRandom);
+  }();
+  gAreHooksActive = true;
+  return sSuccess;
+}
+
+void ExitInterception() { gAreHooksActive = false; }
+
+DWORD WINAPI TestIsFallbackTriggeredThreadProc(LPVOID aParameter) {
+  auto testedFunction = reinterpret_cast<void (*)()>(aParameter);
+  EXPECT_TRUE(InitInterception());
+  MOZ_SEH_TRY { testedFunction(); }
+  MOZ_SEH_EXCEPT(EXCEPTION_EXECUTE_HANDLER) {
+    // Catch a potential Rust panic
+    gHasPanicked = true;
+  }
+  ExitInterception();
+  return 0;
+}
+
+// This function hooks BCryptGenRandom to make it fail, and hooks RtlGenRandom
+// to allow us to ensure that it gets visited as a fallback for
+// BCryptGenRandom.
+void TestIsFallbackTriggered(void (*aTestedFunction)()) {
+  gHasPanicked = false;
+  gHasReachedBCryptGenRandom = false;
+  gHasReachedRtlGenRandom = false;
+
+  // The HashMap test must run on a new thread, because some random bytes have
+  // already been collected but not used on the current thread by previous
+  // calls to HashMap::new in various locations of the code base. These bytes
+  // would be recycled instead of calling into BCryptGenRandom and RtlGenRandom
+  // if running the HashMap test on the current thread.
+  auto thread =
+      ::CreateThread(nullptr, 0, TestIsFallbackTriggeredThreadProc,
+                     reinterpret_cast<void*>(aTestedFunction), 0, nullptr);
+  EXPECT_TRUE(bool(thread));
+  EXPECT_EQ(::WaitForSingleObject(thread, 5000),
+            static_cast<DWORD>(WAIT_OBJECT_0));
+
+  EXPECT_FALSE(gHasPanicked);
+  EXPECT_TRUE(gHasReachedBCryptGenRandom);
+  EXPECT_TRUE(gHasReachedRtlGenRandom);
+}
+
+extern "C" void Rust_TriggerGenRandomFromHashMap();
+extern "C" void Rust_TriggerGenRandomFromUuid();
+
+TEST(TestBCryptFallback, HashMapTriggersFallback)
+{ TestIsFallbackTriggered(Rust_TriggerGenRandomFromHashMap); }
+
+TEST(TestBCryptFallback, UuidTriggersFallback)
+{ TestIsFallbackTriggered(Rust_TriggerGenRandomFromUuid); }
diff --git a/toolkit/xre/dllservices/tests/gtest/rust/moz.build b/toolkit/xre/dllservices/tests/gtest/rust/moz.build
new file mode 100644
index 0000000000..eea8b9e978
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/rust/moz.build
@@ -0,0 +1,11 @@
+# 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/.
+
+Library("dllservicestest")
+
+UNIFIED_SOURCES += [
+    "TestBCryptFallback.cpp",
+]
+
+FINAL_LIBRARY = "xul-gtest"
diff --git a/toolkit/xre/dllservices/tests/gtest/rust/test.rs b/toolkit/xre/dllservices/tests/gtest/rust/test.rs
new file mode 100644
index 0000000000..51c2a6e156
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/gtest/rust/test.rs
@@ -0,0 +1,19 @@
+/* -*- Mode: rust; rust-indent-offset: 2 -*- */
+/* 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/. */
+
+use std::collections::HashMap;
+
+extern crate uuid;
+use uuid::Uuid;
+
+#[no_mangle]
+pub extern "C" fn Rust_TriggerGenRandomFromHashMap() -> () {
+    let _: HashMap<u32, u32> = HashMap::new();
+}
+
+#[no_mangle]
+pub extern "C" fn Rust_TriggerGenRandomFromUuid() -> () {
+    let _: Uuid = Uuid::new_v4();
+}
diff --git a/toolkit/xre/dllservices/tests/moz.build b/toolkit/xre/dllservices/tests/moz.build
new file mode 100644
index 0000000000..957243a476
--- /dev/null
+++ b/toolkit/xre/dllservices/tests/moz.build
@@ -0,0 +1,47 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# 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/.
+
+GeckoCppUnitTests(
+    [
+        "TestDllBlocklistAssumptions",
+        "TestDllInterceptor",
+        "TestIATPatcher",
+        "TestMMPolicy",
+    ],
+    linkage=None,
+)
+
+if CONFIG["CPU_ARCH"] in ("x86", "x86_64"):
+    # Cross-process interceptors not yet supported on aarch64
+    GeckoCppUnitTests(
+        [
+            "TestDllInterceptorCrossProcess",
+        ],
+        linkage=None,
+    )
+
+OS_LIBS += [
+    "advapi32",
+    "ntdll",
+    "ole32",
+    "shlwapi",
+    "user32",
+    "uuid",
+]
+
+DELAYLOAD_DLLS += [
+    "shlwapi.dll",
+]
+
+if CONFIG["CC_TYPE"] in ("gcc", "clang"):
+    # This allows us to use wmain as the entry point on mingw
+    LDFLAGS += [
+        "-municode",
+    ]
+
+TEST_DIRS += [
+    "gtest",
+]