[sandbox] Initialize sandbox during V8::Initialize

As sandboxed pointers are now default-enabled when the sandbox is
enabled, it is no longer possible to deactivate the sandbox at runtime.
This CL therefore removes all the logic that was required to support a
sandbox that could be disabled at runtime, moves the initialization of
the sandbox into V8::Initialize, and deprecates V8::InitializeSandbox.

This change also makes the sandbox initialization deterministic if
FLAG_random_seed is supplied.

Bug: v8:10391
Change-Id: Ibd49f7c251b7c58c642f18a551ecc2c391740970
Cq-Include-Trybots: luci.v8.try:v8_linux64_heap_sandbox_dbg_ng,v8_linux_arm64_sim_heap_sandbox_dbg_ng
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3762583Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Commit-Queue: Samuel Groß <saelo@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81746}

include/v8-initialization.h

@@ -198,13 +198,11 @@ class V8_EXPORT V8 {
    * happen as part of V8::Initialize, at which point this function should be
    * removed.
    */
+  V8_DEPRECATE_SOON(
+      "Sandbox initialization now happens during V8::Initialize. Calling this "
+      "function is no longer necessary.")
   static bool InitializeSandbox();
 
-  /**
-   * Returns true if the sandbox has been initialized, false otherwise.
-   */
-  static bool IsSandboxInitialized();
-
   /**
    * Returns true if the sandbox is configured securely.
    *

include/v8-internal.h

@@ -228,16 +228,6 @@ static_assert(kSandboxMinimumReservationSize > kPtrComprCageReservationSize,
               "The minimum reservation size for a sandbox must be larger than "
               "the pointer compression cage contained within it.");
 
-// For now, even if the sandbox is enabled, we still allow backing stores to be
-// allocated outside of it as fallback. This will simplify the initial rollout.
-// However, if sandboxed pointers are also enabled, we must always place
-// backing stores inside the sandbox as they will be referenced though them.
-#ifdef V8_SANDBOXED_POINTERS
-constexpr bool kAllowBackingStoresOutsideSandbox = false;
-#else
-constexpr bool kAllowBackingStoresOutsideSandbox = true;
-#endif  // V8_SANDBOXED_POINTERS
-
 // The size of the virtual memory reservation for an external pointer table.
 // This determines the maximum number of entries in a table. Using a maximum
 // size allows omitting bounds checks on table accesses if the indices are

samples/hello-world.cc

@@ -20,12 +20,6 @@ int main(int argc, char* argv[]) {
   v8::V8::InitializeExternalStartupData(argv[0]);
   std::unique_ptr<v8::Platform> platform = v8::platform::NewDefaultPlatform();
   v8::V8::InitializePlatform(platform.get());
-#ifdef V8_ENABLE_SANDBOX
-  if (!v8::V8::InitializeSandbox()) {
-    fprintf(stderr, "Error initializing the V8 sandbox\n");
-    return 1;
-  }
-#endif
   v8::V8::Initialize();
 
   // Create a new Isolate and make it the current one.

samples/process.cc

@@ -703,12 +703,6 @@ int main(int argc, char* argv[]) {
   v8::V8::InitializeExternalStartupData(argv[0]);
   std::unique_ptr<v8::Platform> platform = v8::platform::NewDefaultPlatform();
   v8::V8::InitializePlatform(platform.get());
-#ifdef V8_ENABLE_SANDBOX
-  if (!v8::V8::InitializeSandbox()) {
-    fprintf(stderr, "Error initializing the V8 sandbox\n");
-    return 1;
-  }
-#endif
   v8::V8::Initialize();
   map<string, string> options;
   string file;

samples/shell.cc

@@ -73,12 +73,6 @@ int main(int argc, char* argv[]) {
   v8::V8::InitializeExternalStartupData(argv[0]);
   std::unique_ptr<v8::Platform> platform = v8::platform::NewDefaultPlatform();
   v8::V8::InitializePlatform(platform.get());
-#ifdef V8_ENABLE_SANDBOX
-  if (!v8::V8::InitializeSandbox()) {
-    fprintf(stderr, "Error initializing the V8 sandbox\n");
-    return 1;
-  }
-#endif
   v8::V8::SetFlagsFromCommandLine(&argc, argv, true);
   v8::V8::Initialize();
   v8::Isolate::CreateParams create_params;

src/api/api.cc

@@ -6079,7 +6079,9 @@ void v8::V8::InitializePlatform(Platform* platform) {
 }
 
 #ifdef V8_ENABLE_SANDBOX
-bool v8::V8::InitializeSandbox() { return i::V8::InitializeSandbox(); }
+// Sandbox initialization now happens during V8::Initialize.
+// TODO(saelo) remove this function once Embedders no longer use it.
+bool v8::V8::InitializeSandbox() { return true; }
 #endif  // V8_ENABLE_SANDBOX
 
 void v8::V8::DisposePlatform() { i::V8::DisposePlatform(); }

src/d8/d8.cc

@@ -5601,9 +5601,6 @@ int Shell::Main(int argc, char* argv[]) {
   }
   v8::V8::InitializePlatform(g_platform.get());
 #ifdef V8_ENABLE_SANDBOX
-  if (!v8::V8::InitializeSandbox()) {
-    FATAL("Could not initialize the sandbox");
-  }
   if (options.enable_sandbox_crash_filter) {
     // Note: this must happen before the Wasm trap handler is installed, so
     // that the Wasm trap handler is invoked first (and can handle Wasm OOB

src/init/isolate-allocator.cc

@@ -77,29 +77,15 @@ void IsolateAllocator::InitializeOncePerProcess() {
   PtrComprCageReservationParams params;
   base::AddressRegion existing_reservation;
 #ifdef V8_ENABLE_SANDBOX
-  // For now, we allow the sandbox to be disabled even when compiling with
-  // v8_enable_sandbox. This fallback will be disallowed in the future, at the
-  // latest once sandboxed pointers are enabled.
-  if (GetProcessWideSandbox()->is_disabled()) {
-    CHECK(kAllowBackingStoresOutsideSandbox);
-  } else {
-    auto sandbox = GetProcessWideSandbox();
-    CHECK(sandbox->is_initialized());
-    // The pointer compression cage must be placed at the start of the sandbox.
-
-    // TODO(chromium:12180) this currently assumes that no other pages were
-    // allocated through the cage's page allocator in the meantime. In the
-    // future, the cage initialization will happen just before this function
-    // runs, and so this will be guaranteed. Currently however, it is possible
-    // that the embedder accidentally uses the cage's page allocator prior to
-    // initializing V8, in which case this CHECK will likely fail.
-    Address base = sandbox->address_space()->AllocatePages(
-        sandbox->base(), params.reservation_size, params.base_alignment,
-        PagePermissions::kNoAccess);
-    CHECK_EQ(sandbox->base(), base);
-    existing_reservation = base::AddressRegion(base, params.reservation_size);
-    params.page_allocator = sandbox->page_allocator();
-  }
+  // The pointer compression cage must be placed at the start of the sandbox.
+  auto sandbox = GetProcessWideSandbox();
+  CHECK(sandbox->is_initialized());
+  Address base = sandbox->address_space()->AllocatePages(
+      sandbox->base(), params.reservation_size, params.base_alignment,
+      PagePermissions::kNoAccess);
+  CHECK_EQ(sandbox->base(), base);
+  existing_reservation = base::AddressRegion(base, params.reservation_size);
+  params.page_allocator = sandbox->page_allocator();
 #endif
   if (!GetProcessWidePtrComprCage()->InitReservation(params,
                                                      existing_reservation)) {

src/init/v8.cc

@@ -112,17 +112,6 @@ void V8::InitializePlatform(v8::Platform* platform) {
   AdvanceStartupState(V8StartupState::kPlatformInitialized);
 }
 
-#ifdef V8_ENABLE_SANDBOX
-bool V8::InitializeSandbox() {
-  // Platform must have been initialized already.
-  CHECK(platform_);
-  v8::VirtualAddressSpace* vas = GetPlatformVirtualAddressSpace();
-  GetProcessWideSandbox()->Initialize(vas);
-  CHECK_EQ(kSandboxSize, GetProcessWideSandbox()->size());
-  return true;
-}
-#endif  // V8_ENABLE_SANDBOX
-
 #define DISABLE_FLAG(flag)                                                    \
   if (FLAG_##flag) {                                                          \
     PrintF(stderr,                                                            \
@@ -134,16 +123,6 @@ void V8::Initialize() {
   AdvanceStartupState(V8StartupState::kV8Initializing);
   CHECK(platform_);
 
-#ifdef V8_ENABLE_SANDBOX
-  if (!kAllowBackingStoresOutsideSandbox) {
-    CHECK(GetProcessWideSandbox()->is_initialized());
-  } else if (!GetProcessWideSandbox()->is_initialized()) {
-    // For now, we still allow the sandbox to be disabled even if V8 was
-    // compiled with V8_ENABLE_SANDBOX. This will eventually be forbidden.
-    GetProcessWideSandbox()->Disable();
-  }
-#endif  // V8_ENABLE_SANDBOX
-
   // Update logging information before enforcing flag implications.
   FlagValue<bool>* log_all_flags[] = {&FLAG_turbo_profiling_log_builtins,
                                       &FLAG_log_all,
@@ -238,7 +217,10 @@ void V8::Initialize() {
 
   base::OS::Initialize(FLAG_hard_abort, FLAG_gc_fake_mmap);
 
-  if (FLAG_random_seed) SetRandomMmapSeed(FLAG_random_seed);
+  if (FLAG_random_seed) {
+    GetPlatformPageAllocator()->SetRandomMmapSeed(FLAG_random_seed);
+    GetPlatformVirtualAddressSpace()->SetRandomSeed(FLAG_random_seed);
+  }
 
   if (FLAG_print_flag_values) FlagList::PrintValues();
 
@@ -250,6 +232,12 @@ void V8::Initialize() {
   // already reads flags, so they should not be changed afterwards.
   if (FLAG_freeze_flags_after_init) FlagList::FreezeFlags();
 
+#if defined(V8_ENABLE_SANDBOX)
+  // If enabled, the sandbox must be initialized first.
+  GetProcessWideSandbox()->Initialize(GetPlatformVirtualAddressSpace());
+  CHECK_EQ(kSandboxSize, GetProcessWideSandbox()->size());
+#endif
+
 #if defined(V8_USE_PERFETTO)
   if (perfetto::Tracing::IsInitialized()) TrackEvent::Register();
 #endif

src/init/v8.h

@@ -42,10 +42,6 @@ class V8 : public AllStatic {
   [[noreturn]] V8_EXPORT_PRIVATE static void FatalProcessOutOfMemory(
       Isolate* isolate, const char* location, const char* detail);
 
-#ifdef V8_ENABLE_SANDBOX
-  static bool InitializeSandbox();
-#endif
-
   static void InitializePlatform(v8::Platform* platform);
   static void DisposePlatform();
   V8_EXPORT_PRIVATE static v8::Platform* GetCurrentPlatform();

src/objects/backing-store.cc

@@ -170,17 +170,7 @@ BackingStore::~BackingStore() {
     return;
   }
 
-  PageAllocator* page_allocator = GetPlatformPageAllocator();
-  // TODO(saelo) here and elsewhere in this file, replace with
-  // GetArrayBufferPageAllocator once the fallback to the platform page
-  // allocator is no longer allowed.
-#ifdef V8_ENABLE_SANDBOX
-  if (GetProcessWideSandbox()->Contains(buffer_start_)) {
-    page_allocator = GetSandboxPageAllocator();
-  } else {
-    DCHECK(kAllowBackingStoresOutsideSandbox);
-  }
-#endif  // V8_ENABLE_SANDBOX
+  PageAllocator* page_allocator = GetArrayBufferPageAllocator();
 
 #if V8_ENABLE_WEBASSEMBLY
   if (is_wasm_memory_) {
@@ -387,22 +377,8 @@ std::unique_ptr<BackingStore> BackingStore::TryAllocateAndPartiallyCommitMemory(
   // Allocate pages (inaccessible by default).
   //--------------------------------------------------------------------------
   void* allocation_base = nullptr;
-  PageAllocator* page_allocator = GetPlatformPageAllocator();
+  PageAllocator* page_allocator = GetArrayBufferPageAllocator();
   auto allocate_pages = [&] {
-#ifdef V8_ENABLE_SANDBOX
-    page_allocator = GetSandboxPageAllocator();
-    allocation_base = AllocatePages(page_allocator, nullptr, reservation_size,
-                                    page_size, PageAllocator::kNoAccess);
-    if (allocation_base) return true;
-    // We currently still allow falling back to the platform page allocator if
-    // the sandbox page allocator fails. This will eventually be removed.
-    // TODO(chromium:1218005) once we forbid the fallback, we should have a
-    // single API, e.g. GetArrayBufferPageAllocator(), that returns the correct
-    // page allocator to use here depending on whether the sandbox is enabled
-    // or not.
-    if (!kAllowBackingStoresOutsideSandbox) return false;
-    page_allocator = GetPlatformPageAllocator();
-#endif  // V8_ENABLE_SANDBOX
     allocation_base = AllocatePages(page_allocator, nullptr, reservation_size,
                                     page_size, PageAllocator::kNoAccess);
     return allocation_base != nullptr;

src/sandbox/sandbox.cc

@@ -155,7 +155,6 @@ void Sandbox::Initialize(v8::VirtualAddressSpace* vas) {
 bool Sandbox::Initialize(v8::VirtualAddressSpace* vas, size_t size,
                          bool use_guard_regions) {
   CHECK(!initialized_);
-  CHECK(!disabled_);
   CHECK(base::bits::IsPowerOfTwo(size));
   CHECK(vas->CanAllocateSubspaces());
 
@@ -207,7 +206,6 @@ bool Sandbox::InitializeAsPartiallyReservedSandbox(v8::VirtualAddressSpace* vas,
                                                    size_t size,
                                                    size_t size_to_reserve) {
   CHECK(!initialized_);
-  CHECK(!disabled_);
   CHECK(base::bits::IsPowerOfTwo(size));
   CHECK(base::bits::IsPowerOfTwo(size_to_reserve));
   CHECK_LT(size_to_reserve, size);
@@ -290,7 +288,6 @@ void Sandbox::TearDown() {
     constants_.Reset();
 #endif
   }
-  disabled_ = false;
 }
 
 #endif  // V8_ENABLE_SANDBOX

src/sandbox/sandbox.h

@@ -72,17 +72,6 @@ class V8_EXPORT_PRIVATE Sandbox {
    */
   void Initialize(v8::VirtualAddressSpace* vas);
 
-  /**
-   * Disable this sandbox.
-   *
-   * TODO(saelo) remove this once the sandbox is mandatory when enabled at
-   * compile time.
-   */
-  void Disable() {
-    CHECK(!initialized_);
-    disabled_ = true;
-  }
-
   /**
    * Tear down this sandbox.
    *
@@ -95,15 +84,6 @@ class V8_EXPORT_PRIVATE Sandbox {
    */
   bool is_initialized() const { return initialized_; }
 
-  /**
-   * Whether this sandbox is enabled or not.
-   *
-   * TODO(saelo) remove these two once the sandbox is mandatory when enabled at
-   * compile time.
-   */
-  bool is_disabled() const { return disabled_; }
-  bool is_enabled() const { return !disabled_; }
-
   /**
    * Returns true if this sandbox is a partially-reserved sandbox.
    *
@@ -244,7 +224,6 @@ class V8_EXPORT_PRIVATE Sandbox {
   size_t reservation_size_ = 0;
 
   bool initialized_ = false;
-  bool disabled_ = false;
 
   // The virtual address subspace backing the sandbox.
   std::unique_ptr<v8::VirtualAddressSpace> address_space_;

src/snapshot/mksnapshot.cc

@@ -243,11 +243,6 @@ int main(int argc, char** argv) {
   v8::V8::InitializeICUDefaultLocation(argv[0]);
   std::unique_ptr<v8::Platform> platform = v8::platform::NewDefaultPlatform();
   v8::V8::InitializePlatform(platform.get());
-#ifdef V8_ENABLE_SANDBOX
-  if (!v8::V8::InitializeSandbox()) {
-    FATAL("Could not initialize the sandbox");
-  }
-#endif
   v8::V8::Initialize();
 
   {

src/utils/allocation.cc

@@ -96,14 +96,8 @@ v8::VirtualAddressSpace* GetPlatformVirtualAddressSpace() {
 
 #ifdef V8_ENABLE_SANDBOX
 v8::PageAllocator* GetSandboxPageAllocator() {
-  // TODO(chromium:1218005) remove this code once the cage is no longer
-  // optional.
-  if (GetProcessWideSandbox()->is_disabled()) {
-    return GetPlatformPageAllocator();
-  } else {
-    CHECK(GetProcessWideSandbox()->is_initialized());
-    return GetProcessWideSandbox()->page_allocator();
-  }
+  CHECK(GetProcessWideSandbox()->is_initialized());
+  return GetProcessWideSandbox()->page_allocator();
 }
 #endif
 
@@ -185,10 +179,6 @@ size_t AllocatePageSize() {
 
 size_t CommitPageSize() { return GetPlatformPageAllocator()->CommitPageSize(); }
 
-void SetRandomMmapSeed(int64_t seed) {
-  GetPlatformPageAllocator()->SetRandomMmapSeed(seed);
-}
-
 void* GetRandomMmapAddr() {
   return GetPlatformPageAllocator()->GetRandomMmapAddr();
 }

src/utils/allocation.h

@@ -131,10 +131,6 @@ V8_EXPORT_PRIVATE size_t AllocatePageSize();
 // Gets the granularity at which the permissions and release calls can be made.
 V8_EXPORT_PRIVATE size_t CommitPageSize();
 
-// Sets the random seed so that GetRandomMmapAddr() will generate repeatable
-// sequences of random mmap addresses.
-V8_EXPORT_PRIVATE void SetRandomMmapSeed(int64_t seed);
-
 // Generate a random address to be used for hinting allocation calls.
 V8_EXPORT_PRIVATE void* GetRandomMmapAddr();
 

src/wasm/c-api.cc

@@ -393,11 +393,6 @@ auto Engine::make(own<Config>&& config) -> own<Engine> {
   if (!engine) return own<Engine>();
   engine->platform = v8::platform::NewDefaultPlatform();
   v8::V8::InitializePlatform(engine->platform.get());
-#ifdef V8_ENABLE_SANDBOX
-  if (!v8::V8::InitializeSandbox()) {
-    FATAL("Could not initialize the sandbox");
-  }
-#endif
   v8::V8::Initialize();
   return make_own(seal<Engine>(engine));
 }

test/cctest/cctest.cc

@@ -119,9 +119,6 @@ void CcTest::Run(const char* snapshot_directory) {
     platform = std::move(underlying_default_platform);
   }
   v8::V8::InitializePlatform(platform.get());
-#ifdef V8_ENABLE_SANDBOX
-  CHECK(v8::V8::InitializeSandbox());
-#endif
   cppgc::InitializeProcess(platform->GetPageAllocator());
 
   // Allow changing flags in cctests.

test/fuzzer/fuzzer-support.cc

@@ -28,11 +28,6 @@ FuzzerSupport::FuzzerSupport(int* argc, char*** argv) {
   v8::V8::InitializeExternalStartupData((*argv)[0]);
   platform_ = v8::platform::NewDefaultPlatform();
   v8::V8::InitializePlatform(platform_.get());
-#ifdef V8_ENABLE_SANDBOX
-  if (!v8::V8::InitializeSandbox()) {
-    FATAL("Could not initialize the sandbox");
-  }
-#endif
   v8::V8::Initialize();
 
   allocator_ = v8::ArrayBuffer::Allocator::NewDefaultAllocator();

test/inspector/inspector-test.cc

@@ -795,11 +795,6 @@ int InspectorTestMain(int argc, char* argv[]) {
   v8::V8::InitializeICUDefaultLocation(argv[0]);
   std::unique_ptr<Platform> platform(platform::NewDefaultPlatform());
   v8::V8::InitializePlatform(platform.get());
-#ifdef V8_ENABLE_SANDBOX
-  if (!v8::V8::InitializeSandbox()) {
-    FATAL("Could not initialize the sandbox");
-  }
-#endif
   FLAG_abort_on_contradictory_flags = true;
   v8::V8::SetFlagsFromCommandLine(&argc, argv, true);
   v8::V8::InitializeExternalStartupData(argv[0]);

test/mkgrokdump/mkgrokdump.cc

@@ -117,11 +117,6 @@ static int DumpHeapConstants(FILE* out, const char* argv0) {
   // Start up V8.
   std::unique_ptr<v8::Platform> platform = v8::platform::NewDefaultPlatform();
   v8::V8::InitializePlatform(platform.get());
-#ifdef V8_ENABLE_SANDBOX
-  if (!v8::V8::InitializeSandbox()) {
-    FATAL("Could not initialize the sandbox");
-  }
-#endif
   v8::V8::Initialize();
   v8::V8::InitializeExternalStartupData(argv0);
   Isolate::CreateParams create_params;

test/unittests/heap/cppgc/tests.cc

@@ -29,9 +29,6 @@ void TestWithPlatform::SetUpTestSuite() {
   // For non-standalone builds, we need to initialize V8's platform so that it
   // can be looked-up by trace-event.h.
   v8::V8::InitializePlatform(platform_->GetV8Platform());
-#ifdef V8_ENABLE_SANDBOX
-  CHECK(v8::V8::InitializeSandbox());
-#endif  // V8_ENABLE_SANDBOX
   v8::V8::Initialize();
 #endif  // !CPPGC_IS_STANDALONE
 }

test/unittests/interpreter/generate-bytecode-expectations.cc

@@ -347,11 +347,6 @@ V8InitializationScope::V8InitializationScope(const char* exec_path)
   v8::V8::InitializeICUDefaultLocation(exec_path);
   v8::V8::InitializeExternalStartupData(exec_path);
   v8::V8::InitializePlatform(platform_.get());
-#ifdef V8_ENABLE_SANDBOX
-  if (!v8::V8::InitializeSandbox()) {
-    FATAL("Could not initialize the sandbox");
-  }
-#endif
   v8::V8::Initialize();
 
   v8::Isolate::CreateParams create_params;

test/unittests/libplatform/single-threaded-default-platform-unittest.cc

@@ -15,9 +15,6 @@ class WithSingleThreadedDefaultPlatformMixin : public TMixin {
     platform_ = v8::platform::NewSingleThreadedDefaultPlatform();
     CHECK_NOT_NULL(platform_.get());
     v8::V8::InitializePlatform(platform_.get());
-#ifdef V8_ENABLE_SANDBOX
-    CHECK(v8::V8::InitializeSandbox());
-#endif  // V8_ENABLE_SANDBOX
     v8::V8::Initialize();
   }
 

test/unittests/sandbox/sandbox-unittest.cc

@@ -20,7 +20,6 @@ TEST(SandboxTest, Initialization) {
   Sandbox sandbox;
 
   EXPECT_FALSE(sandbox.is_initialized());
-  EXPECT_FALSE(sandbox.is_disabled());
   EXPECT_FALSE(sandbox.is_partially_reserved());
   EXPECT_EQ(sandbox.size(), 0UL);
 

test/unittests/test-utils.h

@@ -37,9 +37,6 @@ class WithDefaultPlatformMixin : public TMixin {
         0, v8::platform::IdleTaskSupport::kEnabled);
     CHECK_NOT_NULL(platform_.get());
     v8::V8::InitializePlatform(platform_.get());
-#ifdef V8_ENABLE_SANDBOX
-    CHECK(v8::V8::InitializeSandbox());
-#endif
     // Allow changing flags in unit tests.
     // TODO(12887): Fix tests to avoid changing flag values after
     // initialization.

tools/wasm/module-inspector.cc

@@ -446,12 +446,6 @@ int main(int argc, char** argv) {
   v8::V8::InitializeExternalStartupData(argv[0]);
   std::unique_ptr<v8::Platform> platform = v8::platform::NewDefaultPlatform();
   v8::V8::InitializePlatform(platform.get());
-#ifdef V8_ENABLE_SANDBOX
-  if (!v8::V8::InitializeSandbox()) {
-    fprintf(stderr, "Error initializing the V8 sandbox\n");
-    return 1;
-  }
-#endif
   v8::V8::Initialize();
 
   switch (options.action) {