electron/shell/renderer/web_worker_observer.cc
Shelley Vohr 8874306dc0
fix: window.open causing occasional Node.js crashes (#38754)
* fix: window.open causing occasional Node.js crashes

* chore: always free isolate data

* chore: clear pending ticks in worker thread

* fix: UAF crash when creating WebWorkerObserver

---------

Co-authored-by: deepak1556 <hop2deep@gmail.com>
2023-07-18 10:41:50 +02:00

107 lines
3.4 KiB
C++

// Copyright (c) 2017 GitHub, Inc.
// Use of this source code is governed by the MIT license that can be
// found in the LICENSE file.
#include "shell/renderer/web_worker_observer.h"
#include <utility>
#include "base/no_destructor.h"
#include "base/threading/thread_local.h"
#include "shell/common/api/electron_bindings.h"
#include "shell/common/gin_helper/event_emitter_caller.h"
#include "shell/common/node_bindings.h"
#include "shell/common/node_includes.h"
namespace electron {
namespace {
static base::NoDestructor<base::ThreadLocalOwnedPointer<WebWorkerObserver>>
lazy_tls;
} // namespace
// static
WebWorkerObserver* WebWorkerObserver::GetCurrent() {
return lazy_tls->Get();
}
// static
WebWorkerObserver* WebWorkerObserver::Create() {
auto obs = std::make_unique<WebWorkerObserver>();
auto* obs_raw = obs.get();
lazy_tls->Set(std::move(obs));
return obs_raw;
}
WebWorkerObserver::WebWorkerObserver()
: node_bindings_(
NodeBindings::Create(NodeBindings::BrowserEnvironment::kWorker)),
electron_bindings_(
std::make_unique<ElectronBindings>(node_bindings_->uv_loop())) {}
WebWorkerObserver::~WebWorkerObserver() = default;
void WebWorkerObserver::WorkerScriptReadyForEvaluation(
v8::Local<v8::Context> worker_context) {
v8::Context::Scope context_scope(worker_context);
auto* isolate = worker_context->GetIsolate();
v8::MicrotasksScope microtasks_scope(
isolate, worker_context->GetMicrotaskQueue(),
v8::MicrotasksScope::kDoNotRunMicrotasks);
// Start the embed thread.
node_bindings_->PrepareEmbedThread();
// Setup node tracing controller.
if (!node::tracing::TraceEventHelper::GetAgent())
node::tracing::TraceEventHelper::SetAgent(node::CreateAgent());
// Setup node environment for each window.
v8::Maybe<bool> initialized = node::InitializeContext(worker_context);
CHECK(!initialized.IsNothing() && initialized.FromJust());
node::Environment* env =
node_bindings_->CreateEnvironment(worker_context, nullptr);
// Add Electron extended APIs.
electron_bindings_->BindTo(env->isolate(), env->process_object());
// Load everything.
node_bindings_->LoadEnvironment(env);
// Make uv loop being wrapped by window context.
node_bindings_->set_uv_env(env);
// Give the node loop a run to make sure everything is ready.
node_bindings_->StartPolling();
}
void WebWorkerObserver::ContextWillDestroy(v8::Local<v8::Context> context) {
node::Environment* env = node::Environment::GetCurrent(context);
if (env)
gin_helper::EmitEvent(env->isolate(), env->process_object(), "exit");
// Destroying the node environment will also run the uv loop,
// Node.js expects `kExplicit` microtasks policy and will run microtasks
// checkpoints after every call into JavaScript. Since we use a different
// policy in the renderer - switch to `kExplicit`
v8::MicrotaskQueue* microtask_queue = context->GetMicrotaskQueue();
auto old_policy = microtask_queue->microtasks_policy();
DCHECK_EQ(microtask_queue->GetMicrotasksScopeDepth(), 0);
microtask_queue->set_microtasks_policy(v8::MicrotasksPolicy::kExplicit);
node::FreeEnvironment(env);
node::FreeIsolateData(node_bindings_->isolate_data(context));
node_bindings_->clear_isolate_data(context);
microtask_queue->set_microtasks_policy(old_policy);
// ElectronBindings is tracking node environments.
electron_bindings_->EnvironmentDestroyed(env);
if (lazy_tls->Get())
lazy_tls->Set(nullptr);
}
} // namespace electron