src: fix async hooks crashing when there is no node context

src/env.cc

@@ -3,6 +3,7 @@
 #include "node_buffer.h"
 #include "node_platform.h"
 #include "node_file.h"
+#include "node_context_data.h"
 #include "tracing/agent.h"
 
 #include <stdio.h>
@@ -24,6 +25,10 @@ using v8::StackTrace;
 using v8::String;
 using v8::Value;
 
+const int kNodeContextTag = 0x6e6f64;
+void* kNodeContextTagPtr = const_cast<void*>(
+    static_cast<const void*>(&kNodeContextTag));
+
 IsolateData::IsolateData(Isolate* isolate,
                          uv_loop_t* event_loop,
                          MultiIsolatePlatform* platform,
@@ -195,6 +200,10 @@ void Environment::Start(int argc,
   set_process_object(process_object);
 
   SetupProcessObject(this, argc, argv, exec_argc, exec_argv);
+
+  // Used by EnvPromiseHook to know that we are on a node context.
+  context()->SetAlignedPointerInEmbedderData(ContextEmbedderIndex::kContextTag, kNodeContextTagPtr);
+
   LoadAsyncWrapperInfo(this);
 
   static uv_once_t init_once = UV_ONCE_INIT;
@@ -364,7 +373,19 @@ bool Environment::RemovePromiseHook(promise_hook_func fn, void* arg) {
 void Environment::EnvPromiseHook(v8::PromiseHookType type,
                                  v8::Local<v8::Promise> promise,
                                  v8::Local<v8::Value> parent) {
-  Environment* env = Environment::GetCurrent(promise->CreationContext());
+  Local<v8::Context> context = promise->CreationContext();
+
+  // Grow the embedder data if necessary to make sure we are not out of bounds
+  // when reading the magic number.
+  context->SetAlignedPointerInEmbedderData(ContextEmbedderIndex::kContextTagBoundary, nullptr);
+  int* magicNumberPtr = reinterpret_cast<int*>(
+      context->GetAlignedPointerFromEmbedderData(ContextEmbedderIndex::kContextTag));
+  if (magicNumberPtr != kNodeContextTagPtr) {
+    return;
+  }
+
+  Environment* env = Environment::GetCurrent(context);
+
   for (const PromiseHookCallback& hook : env->promise_hooks_) {
     hook.cb_(type, promise, parent, hook.arg_);
   }

src/node_context_data.h

@@ -19,10 +19,20 @@ namespace node {
 #define NODE_CONTEXT_ALLOW_WASM_CODE_GENERATION_INDEX 34
 #endif
 
+#ifndef NODE_CONTEXT_TAG
+#define NODE_CONTEXT_TAG 35
+#endif
+
+#ifndef NODE_CONTEXT_TAG_BOUNDARY
+#define NODE_CONTEXT_TAG_BOUNDARY 36
+#endif
+
 enum ContextEmbedderIndex {
   kEnvironment = NODE_CONTEXT_EMBEDDER_DATA_INDEX,
   kSandboxObject = NODE_CONTEXT_SANDBOX_OBJECT_INDEX,
   kAllowWasmCodeGeneration = NODE_CONTEXT_ALLOW_WASM_CODE_GENERATION_INDEX,
+  kContextTag = NODE_CONTEXT_TAG,
+  kContextTagBoundary = NODE_CONTEXT_TAG_BOUNDARY,
 };
 
 }  // namespace node