feat: enable v8 sandboxed pointers (electron#34724)

* feat: enable v8 sandboxed pointers

* update breaking-changes.md

* update zero-fill patch

benchmarks showed the function call was slower

Author: nornagon

build/args/all.gn

@@ -45,7 +45,3 @@ enable_cet_shadow_stack = false
 # V8 in the browser process.
 # Ref: https://source.chromium.org/chromium/chromium/src/+/45fba672185aae233e75d6ddc81ea1e0b30db050:v8/BUILD.gn;l=281
 is_cfi = false
-
-# TODO(nornagon): this is disabled until node.js's internals can be made
-# compatible with sandboxed pointers.
-v8_enable_sandboxed_pointers = false

docs/breaking-changes.md

@@ -14,6 +14,13 @@ This document uses the following convention to categorize breaking changes:
 
 ## Planned Breaking API Changes (20.0)
 
+### Behavior Changed: V8 Memory Cage enabled
+
+The V8 memory cage has been enabled, which has implications for native modules
+which wrap non-V8 memory with `ArrayBuffer` or `Buffer`. See the [blog post
+about the V8 memory cage](https://www.electronjs.org/blog/v8-memory-cage) for
+more details.
+
 ### API Changed: `webContents.printToPDF()`
 
 `webContents.printToPDF()` has been modified to conform to [`Page.printToPDF`](https://chromedevtools.github.io/devtools-protocol/tot/Page/#method-printToPDF) in the Chrome DevTools Protocol. This has been changes in order to

patches/node/support_v8_sandboxed_pointers.patch

@@ -6,84 +6,27 @@ Subject: support V8 sandboxed pointers
 This refactors several allocators to allocate within the V8 memory cage,
 allowing them to be compatible with the V8_SANDBOXED_POINTERS feature.
 
-diff --git a/lib/internal/bootstrap/pre_execution.js b/lib/internal/bootstrap/pre_execution.js
-index 4c459b58b5a048d9d8a4f15f4011e7cce68089f4..6fb4c8d4567aee5b313ad621ea42699a196f18c7 100644
---- a/lib/internal/bootstrap/pre_execution.js
-+++ b/lib/internal/bootstrap/pre_execution.js
-@@ -14,7 +14,6 @@ const {
-   getOptionValue,
-   getEmbedderOptions,
- } = require('internal/options');
--const { reconnectZeroFillToggle } = require('internal/buffer');
- const {
-   defineOperation,
-   emitExperimentalWarning,
-@@ -26,10 +25,6 @@ const { ERR_MANIFEST_ASSERT_INTEGRITY } = require('internal/errors').codes;
- const assert = require('internal/assert');
- 
- function prepareMainThreadExecution(expandArgv1 = false) {
--  // TODO(joyeecheung): this is also necessary for workers when they deserialize
--  // this toggle from the snapshot.
--  reconnectZeroFillToggle();
--
-   // Patch the process object with legacy properties and normalizations
-   patchProcessObject(expandArgv1);
-   setupTraceCategoryState();
-diff --git a/lib/internal/buffer.js b/lib/internal/buffer.js
-index bd38cf48a7fc6e8d61d8f11fa15c34aee182cbe3..1aa071cdc071dcdaf5c3b4bed0d3d76e5871731d 100644
---- a/lib/internal/buffer.js
-+++ b/lib/internal/buffer.js
-@@ -30,7 +30,7 @@ const {
-   hexWrite,
-   ucs2Write,
-   utf8Write,
--  getZeroFillToggle
-+  setZeroFillToggle
- } = internalBinding('buffer');
- const {
-   untransferable_object_private_symbol,
-@@ -1055,24 +1055,15 @@ function markAsUntransferable(obj) {
- // in C++.
- // |zeroFill| can be undefined when running inside an isolate where we
- // do not own the ArrayBuffer allocator.  Zero fill is always on in that case.
--let zeroFill = getZeroFillToggle();
- function createUnsafeBuffer(size) {
--  zeroFill[0] = 0;
-+  setZeroFillToggle(false);
-   try {
-     return new FastBuffer(size);
-   } finally {
--    zeroFill[0] = 1;
-+    setZeroFillToggle(true)
-   }
- }
- 
--// The connection between the JS land zero fill toggle and the
--// C++ one in the NodeArrayBufferAllocator gets lost if the toggle
--// is deserialized from the snapshot, because V8 owns the underlying
--// memory of this toggle. This resets the connection.
--function reconnectZeroFillToggle() {
--  zeroFill = getZeroFillToggle();
--}
--
- module.exports = {
-   FastBuffer,
-   addBufferPrototypeMethods,
-@@ -1080,5 +1071,4 @@ module.exports = {
-   createUnsafeBuffer,
-   readUInt16BE,
-   readUInt32BE,
--  reconnectZeroFillToggle
- };
 diff --git a/src/api/environment.cc b/src/api/environment.cc
-index 2abf5994405e8da2a04d1b23b75ccd3658398474..024d612a04d83583b397549589d994e32cf0107f 100644
+index 2abf5994405e8da2a04d1b23b75ccd3658398474..b06e8529bb8ca2fa6d7f0735531bbbf39da6af12 100644
 --- a/src/api/environment.cc
 +++ b/src/api/environment.cc
-@@ -83,16 +83,16 @@ MaybeLocal<Value> PrepareStackTraceCallback(Local<Context> context,
+@@ -80,19 +80,27 @@ MaybeLocal<Value> PrepareStackTraceCallback(Local<Context> context,
+   return result;
+ }
+ 
++NodeArrayBufferAllocator::NodeArrayBufferAllocator() {
++  zero_fill_field_ = static_cast<uint32_t*>(allocator_->Allocate(sizeof(*zero_fill_field_)));
++}
++
++NodeArrayBufferAllocator::~NodeArrayBufferAllocator() {
++  allocator_->Free(zero_fill_field_, sizeof(*zero_fill_field_));
++}
++
  void* NodeArrayBufferAllocator::Allocate(size_t size) {
    void* ret;
-   if (zero_fill_field_ || per_process::cli_options->zero_fill_all_buffers)
+-  if (zero_fill_field_ || per_process::cli_options->zero_fill_all_buffers)
 -    ret = UncheckedCalloc(size);
++  if (*zero_fill_field_ || per_process::cli_options->zero_fill_all_buffers)
 +    ret = allocator_->Allocate(size);
    else
 -    ret = UncheckedMalloc(size);
@@ -99,7 +42,7 @@ index 2abf5994405e8da2a04d1b23b75ccd3658398474..024d612a04d83583b397549589d994e3
    if (LIKELY(ret != nullptr))
      total_mem_usage_.fetch_add(size, std::memory_order_relaxed);
    return ret;
-@@ -100,7 +100,7 @@ void* NodeArrayBufferAllocator::AllocateUninitialized(size_t size) {
+@@ -100,7 +108,7 @@ void* NodeArrayBufferAllocator::AllocateUninitialized(size_t size) {
 
  void* NodeArrayBufferAllocator::Reallocate(
      void* data, size_t old_size, size_t size) {
@@ -108,7 +51,7 @@ index 2abf5994405e8da2a04d1b23b75ccd3658398474..024d612a04d83583b397549589d994e3
    if (LIKELY(ret != nullptr) || UNLIKELY(size == 0))
      total_mem_usage_.fetch_add(size - old_size, std::memory_order_relaxed);
    return ret;
-@@ -108,7 +108,7 @@ void* NodeArrayBufferAllocator::Reallocate(
+@@ -108,7 +116,7 @@ void* NodeArrayBufferAllocator::Reallocate(
 
  void NodeArrayBufferAllocator::Free(void* data, size_t size) {
    total_mem_usage_.fetch_sub(size, std::memory_order_relaxed);
@@ -209,65 +152,6 @@ index c431159e6f77f8c86844bcadb86012b056d03372..9f57ac58d826cb0aae422ddca54e2136
 
    v8::Local<v8::ArrayBuffer> ToArrayBuffer(Environment* env);
 
-diff --git a/src/node_buffer.cc b/src/node_buffer.cc
-index 215bd8003aabe17e43ac780c723cfe971b437eae..eb00eb6f592e20f3c17a529f30b09673774eb1c1 100644
---- a/src/node_buffer.cc
-+++ b/src/node_buffer.cc
-@@ -1175,33 +1175,14 @@ void SetBufferPrototype(const FunctionCallbackInfo<Value>& args) {
-   env->set_buffer_prototype_object(proto);
- }
- 
--void GetZeroFillToggle(const FunctionCallbackInfo<Value>& args) {
-+void SetZeroFillToggle(const FunctionCallbackInfo<Value>& args) {
-   Environment* env = Environment::GetCurrent(args);
-   NodeArrayBufferAllocator* allocator = env->isolate_data()->node_allocator();
-   Local<ArrayBuffer> ab;
--  // It can be a nullptr when running inside an isolate where we
--  // do not own the ArrayBuffer allocator.
--  if (allocator == nullptr) {
--    // Create a dummy Uint32Array - the JS land can only toggle the C++ land
--    // setting when the allocator uses our toggle. With this the toggle in JS
--    // land results in no-ops.
--    ab = ArrayBuffer::New(env->isolate(), sizeof(uint32_t));
--  } else {
-+  if (allocator != nullptr) {
-     uint32_t* zero_fill_field = allocator->zero_fill_field();
--    std::unique_ptr<BackingStore> backing =
--        ArrayBuffer::NewBackingStore(zero_fill_field,
--                                     sizeof(*zero_fill_field),
--                                     [](void*, size_t, void*) {},
--                                     nullptr);
--    ab = ArrayBuffer::New(env->isolate(), std::move(backing));
-+    *zero_fill_field = args[0]->BooleanValue(env->isolate());
-   }
--
--  ab->SetPrivate(
--      env->context(),
--      env->untransferable_object_private_symbol(),
--      True(env->isolate())).Check();
--
--  args.GetReturnValue().Set(Uint32Array::New(ab, 0, 1));
- }
- 
- void DetachArrayBuffer(const FunctionCallbackInfo<Value>& args) {
-@@ -1310,7 +1291,7 @@ void Initialize(Local<Object> target,
-   env->SetMethod(target, "ucs2Write", StringWrite<UCS2>);
-   env->SetMethod(target, "utf8Write", StringWrite<UTF8>);
- 
--  env->SetMethod(target, "getZeroFillToggle", GetZeroFillToggle);
-+  env->SetMethod(target, "setZeroFillToggle", SetZeroFillToggle);
- }
- 
- }  // anonymous namespace
-@@ -1350,7 +1331,7 @@ void RegisterExternalReferences(ExternalReferenceRegistry* registry) {
-   registry->Register(StringWrite<HEX>);
-   registry->Register(StringWrite<UCS2>);
-   registry->Register(StringWrite<UTF8>);
--  registry->Register(GetZeroFillToggle);
-+  registry->Register(SetZeroFillToggle);
- 
-   registry->Register(DetachArrayBuffer);
-   registry->Register(CopyArrayBuffer);
 diff --git a/src/node_i18n.cc b/src/node_i18n.cc
 index c537a247f55ff070da1988fc8b7309b5692b5c18..59bfb597849cd5a94800d6c83b238ef77245243e 100644
 --- a/src/node_i18n.cc
@@ -282,12 +166,26 @@ index c537a247f55ff070da1988fc8b7309b5692b5c18..59bfb597849cd5a94800d6c83b238ef7
      return ret;
 
 diff --git a/src/node_internals.h b/src/node_internals.h
-index d37be23cd63e82d4040777bd0e17ed449ec0b15b..0b66996f11c66800a7e21ee84fa101450b856227 100644
+index d37be23cd63e82d4040777bd0e17ed449ec0b15b..eb84760593ff5fb5aa6a8104e8714099f24a67a0 100644
 --- a/src/node_internals.h
 +++ b/src/node_internals.h
-@@ -118,6 +118,8 @@ class NodeArrayBufferAllocator : public ArrayBufferAllocator {
+@@ -97,7 +97,9 @@ bool InitializePrimordials(v8::Local<v8::Context> context);
+ 
+ class NodeArrayBufferAllocator : public ArrayBufferAllocator {
+  public:
+-  inline uint32_t* zero_fill_field() { return &zero_fill_field_; }
++  NodeArrayBufferAllocator();
++  ~NodeArrayBufferAllocator() override;
++  inline uint32_t* zero_fill_field() { return zero_fill_field_; }
+ 
+   void* Allocate(size_t size) override;  // Defined in src/node.cc
+   void* AllocateUninitialized(size_t size) override;
+@@ -116,8 +118,10 @@ class NodeArrayBufferAllocator : public ArrayBufferAllocator {
+   }
+ 
   private:
-   uint32_t zero_fill_field_ = 1;  // Boolean but exposed as uint32 to JS land.
+-  uint32_t zero_fill_field_ = 1;  // Boolean but exposed as uint32 to JS land.
++  uint32_t* zero_fill_field_ = nullptr;  // Boolean but exposed as uint32 to JS land.
    std::atomic<size_t> total_mem_usage_ {0};
 +
 +  std::unique_ptr<v8::ArrayBuffer::Allocator> allocator_{v8::ArrayBuffer::Allocator::NewDefaultAllocator()};

patches/v8/.patches

@@ -10,4 +10,3 @@ revert_fix_cppgc_removed_deleted_cstors_in_cppheapcreateparams.patch
 revert_runtime_dhceck_terminating_exception_in_microtasks.patch
 chore_disable_is_execution_terminating_dcheck.patch
 build_remove_legacy_oom_error_callback.patch
-force_disable_v8_sandboxed_pointers.patch