1 files changed, 202 insertions, 0 deletions
diff --git a/security/sandbox/win/SandboxInitialization.cpp b/security/sandbox/win/SandboxInitialization.cpp
new file mode 100644
index 0000000000..8ba8b4e69a
--- /dev/null
+++ b/security/sandbox/win/SandboxInitialization.cpp
@@ -0,0 +1,202 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=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 "SandboxInitialization.h"
+
+#include "base/memory/ref_counted.h"
+#include "nsWindowsDllInterceptor.h"
+#include "sandbox/win/src/process_mitigations.h"
+#include "sandbox/win/src/sandbox_factory.h"
+#include "mozilla/DebugOnly.h"
+#include "mozilla/WindowsProcessMitigations.h"
+
+namespace mozilla {
+namespace sandboxing {
+
+typedef BOOL(WINAPI* CloseHandle_func)(HANDLE hObject);
+static WindowsDllInterceptor::FuncHookType<CloseHandle_func> stub_CloseHandle;
+
+typedef BOOL(WINAPI* DuplicateHandle_func)(
+    HANDLE hSourceProcessHandle, HANDLE hSourceHandle,
+    HANDLE hTargetProcessHandle, LPHANDLE lpTargetHandle, DWORD dwDesiredAccess,
+    BOOL bInheritHandle, DWORD dwOptions);
+static WindowsDllInterceptor::FuncHookType<DuplicateHandle_func>
+    stub_DuplicateHandle;
+
+static BOOL WINAPI patched_CloseHandle(HANDLE hObject) {
+  // Check all handles being closed against the sandbox's tracked handles.
+  base::win::OnHandleBeingClosed(hObject);
+  return stub_CloseHandle(hObject);
+}
+
+static BOOL WINAPI patched_DuplicateHandle(
+    HANDLE hSourceProcessHandle, HANDLE hSourceHandle,
+    HANDLE hTargetProcessHandle, LPHANDLE lpTargetHandle, DWORD dwDesiredAccess,
+    BOOL bInheritHandle, DWORD dwOptions) {
+  // If closing a source handle from our process check it against the sandbox's
+  // tracked handles.
+  if ((dwOptions & DUPLICATE_CLOSE_SOURCE) &&
+      (GetProcessId(hSourceProcessHandle) == ::GetCurrentProcessId())) {
+    base::win::OnHandleBeingClosed(hSourceHandle);
+  }
+
+  return stub_DuplicateHandle(hSourceProcessHandle, hSourceHandle,
+                              hTargetProcessHandle, lpTargetHandle,
+                              dwDesiredAccess, bInheritHandle, dwOptions);
+}
+
+typedef BOOL(WINAPI* ApiSetQueryApiSetPresence_func)(PCUNICODE_STRING,
+                                                     PBOOLEAN);
+static WindowsDllInterceptor::FuncHookType<ApiSetQueryApiSetPresence_func>
+    stub_ApiSetQueryApiSetPresence;
+
+static const WCHAR gApiSetNtUserWindowStation[] =
+    L"ext-ms-win-ntuser-windowstation-l1-1-0";
+
+static BOOL WINAPI patched_ApiSetQueryApiSetPresence(
+    PCUNICODE_STRING aNamespace, PBOOLEAN aPresent) {
+  if (aNamespace && aPresent &&
+      !wcsncmp(aNamespace->Buffer, gApiSetNtUserWindowStation,
+               aNamespace->Length / sizeof(WCHAR))) {
+    *aPresent = FALSE;
+    return TRUE;
+  }
+
+  return stub_ApiSetQueryApiSetPresence(aNamespace, aPresent);
+}
+
+static WindowsDllInterceptor Kernel32Intercept;
+static WindowsDllInterceptor gApiQueryIntercept;
+
+static bool EnableHandleCloseMonitoring() {
+  Kernel32Intercept.Init("kernel32.dll");
+  bool hooked = stub_CloseHandle.Set(Kernel32Intercept, "CloseHandle",
+                                     &patched_CloseHandle);
+  if (!hooked) {
+    return false;
+  }
+
+  hooked = stub_DuplicateHandle.Set(Kernel32Intercept, "DuplicateHandle",
+                                    &patched_DuplicateHandle);
+  if (!hooked) {
+    return false;
+  }
+
+  return true;
+}
+
+/**
+ * There is a bug in COM that causes its initialization to fail when user32.dll
+ * is loaded but Win32k lockdown is enabled. COM uses ApiSetQueryApiSetPresence
+ * to make this check. When we are under Win32k lockdown, we hook
+ * ApiSetQueryApiSetPresence and force it to tell the caller that the DLL of
+ * interest is not present.
+ */
+static void EnableApiQueryInterception() {
+  if (!IsWin32kLockedDown()) {
+    return;
+  }
+
+  gApiQueryIntercept.Init(L"Api-ms-win-core-apiquery-l1-1-0.dll");
+  DebugOnly<bool> hookSetOk = stub_ApiSetQueryApiSetPresence.Set(
+      gApiQueryIntercept, "ApiSetQueryApiSetPresence",
+      &patched_ApiSetQueryApiSetPresence);
+  MOZ_ASSERT(hookSetOk);
+}
+
+static bool ShouldDisableHandleVerifier() {
+#if defined(_X86_) && (defined(EARLY_BETA_OR_EARLIER) || defined(DEBUG))
+  // Chromium only has the verifier enabled for 32-bit and our close monitoring
+  // hooks cause debug assertions for 64-bit anyway.
+  // For x86 keep the verifier enabled by default only for Nightly or debug.
+  return false;
+#else
+  return !getenv("MOZ_ENABLE_HANDLE_VERIFIER");
+#endif
+}
+
+static void InitializeHandleVerifier() {
+  // Disable the handle verifier if we don't want it or can't enable the close
+  // monitoring hooks.
+  if (ShouldDisableHandleVerifier() || !EnableHandleCloseMonitoring()) {
+    base::win::DisableHandleVerifier();
+  }
+}
+
+static sandbox::TargetServices* InitializeTargetServices() {
+  // This might disable the verifier, so we want to do it before it is used.
+  InitializeHandleVerifier();
+
+  EnableApiQueryInterception();
+
+  sandbox::TargetServices* targetServices =
+      sandbox::SandboxFactory::GetTargetServices();
+  if (!targetServices) {
+    return nullptr;
+  }
+
+  if (targetServices->Init() != sandbox::SBOX_ALL_OK) {
+    return nullptr;
+  }
+
+  return targetServices;
+}
+
+sandbox::TargetServices* GetInitializedTargetServices() {
+  static sandbox::TargetServices* sInitializedTargetServices =
+      InitializeTargetServices();
+
+  return sInitializedTargetServices;
+}
+
+void LowerSandbox() { GetInitializedTargetServices()->LowerToken(); }
+
+static sandbox::BrokerServices* InitializeBrokerServices() {
+  // This might disable the verifier, so we want to do it before it is used.
+  InitializeHandleVerifier();
+
+  sandbox::BrokerServices* brokerServices =
+      sandbox::SandboxFactory::GetBrokerServices();
+  if (!brokerServices) {
+    return nullptr;
+  }
+
+  if (brokerServices->Init() != sandbox::SBOX_ALL_OK) {
+    return nullptr;
+  }
+
+  // Comment below copied from Chromium code.
+  // Precreate the desktop and window station used by the renderers.
+  // IMPORTANT: This piece of code needs to run as early as possible in the
+  // process because it will initialize the sandbox broker, which requires
+  // the process to swap its window station. During this time all the UI
+  // will be broken. This has to run before threads and windows are created.
+  scoped_refptr<sandbox::TargetPolicy> policy = brokerServices->CreatePolicy();
+  policy->CreateAlternateDesktop(true);
+
+  // Ensure the relevant mitigations are enforced.
+  mozilla::sandboxing::ApplyParentProcessMitigations();
+
+  return brokerServices;
+}
+
+sandbox::BrokerServices* GetInitializedBrokerServices() {
+  static sandbox::BrokerServices* sInitializedBrokerServices =
+      InitializeBrokerServices();
+
+  return sInitializedBrokerServices;
+}
+
+void ApplyParentProcessMitigations() {
+  // The main reason for this call is for the token hardening, but chromium code
+  // also ensures DEP without ATL thunk so we do the same.
+  sandbox::ApplyProcessMitigationsToCurrentProcess(
+      sandbox::MITIGATION_DEP | sandbox::MITIGATION_DEP_NO_ATL_THUNK |
+      sandbox::MITIGATION_HARDEN_TOKEN_IL_POLICY);
+}
+
+}  // namespace sandboxing
+}  // namespace mozilla