src: add NativeKeyObject base class

             +---------------------+
             |     BaseObject      |
             +---------------------+
                        |
                        |
                        |
             +---------------------+
             |   NativeKeyObject   |
             +---------------------+
                        |
                        |
                        |
             +---------------------+
             |      KeyObject      |
             +---------------------+
               /                 \
              /                   \
             /                     \
            /                       \
+---------------------+    +---------------------+
|   SecretKeyObject   |    | AsymmetricKeyObject |
+---------------------+    +---------------------+
                             /                 \
                            /                   \
                           /                     \
                          /                       \
              +---------------------+   +---------------------+
              |   PublicKeyObject   |   |   PrivateKeyObject  |
              +---------------------+   +---------------------+

PR-URL: #33360
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>

lib/internal/crypto/keys.js

@@ -7,6 +7,7 @@ const {
 
 const {
   KeyObjectHandle,
+  createNativeKeyObjectClass,
   kKeyTypeSecret,
   kKeyTypePublic,
   kKeyTypePrivate,
@@ -42,80 +43,96 @@ for (const m of [[kKeyEncodingPKCS1, 'pkcs1'], [kKeyEncodingPKCS8, 'pkcs8'],
                  [kKeyEncodingSPKI, 'spki'], [kKeyEncodingSEC1, 'sec1']])
   encodingNames[m[0]] = m[1];
 
-class KeyObject {
-  constructor(type, handle) {
-    if (type !== 'secret' && type !== 'public' && type !== 'private')
-      throw new ERR_INVALID_ARG_VALUE('type', type);
-    if (typeof handle !== 'object')
-      throw new ERR_INVALID_ARG_TYPE('handle', 'object', handle);
-
-    this[kKeyType] = type;
-
-    ObjectDefineProperty(this, kHandle, {
-      value: handle,
-      enumerable: false,
-      configurable: false,
-      writable: false
-    });
-  }
+// Creating the KeyObject class is a little complicated due to inheritance
+// and that fact that KeyObjects should be transferrable between threads,
+// which requires the KeyObject base class to be implemented in C++.
+// The creation requires a callback to make sure that the NativeKeyObject
+// base class cannot exist without the other KeyObject implementations.
+const [
+  KeyObject,
+  SecretKeyObject,
+  PublicKeyObject,
+  PrivateKeyObject
+] = createNativeKeyObjectClass((NativeKeyObject) => {
+  // Publicly visible KeyObject class.
+  class KeyObject extends NativeKeyObject {
+    constructor(type, handle) {
+      super();
+      if (type !== 'secret' && type !== 'public' && type !== 'private')
+        throw new ERR_INVALID_ARG_VALUE('type', type);
+      if (typeof handle !== 'object')
+        throw new ERR_INVALID_ARG_TYPE('handle', 'object', handle);
+
+      this[kKeyType] = type;
+
+      ObjectDefineProperty(this, kHandle, {
+        value: handle,
+        enumerable: false,
+        configurable: false,
+        writable: false
+      });
+    }
 
-  get type() {
-    return this[kKeyType];
+    get type() {
+      return this[kKeyType];
+    }
   }
-}
 
-class SecretKeyObject extends KeyObject {
-  constructor(handle) {
-    super('secret', handle);
-  }
+  class SecretKeyObject extends KeyObject {
+    constructor(handle) {
+      super('secret', handle);
+    }
 
-  get symmetricKeySize() {
-    return this[kHandle].getSymmetricKeySize();
-  }
+    get symmetricKeySize() {
+      return this[kHandle].getSymmetricKeySize();
+    }
 
-  export() {
-    return this[kHandle].export();
+    export() {
+      return this[kHandle].export();
+    }
   }
-}
 
-const kAsymmetricKeyType = Symbol('kAsymmetricKeyType');
+  const kAsymmetricKeyType = Symbol('kAsymmetricKeyType');
 
-class AsymmetricKeyObject extends KeyObject {
-  get asymmetricKeyType() {
-    return this[kAsymmetricKeyType] ||
-           (this[kAsymmetricKeyType] = this[kHandle].getAsymmetricKeyType());
+  class AsymmetricKeyObject extends KeyObject {
+    get asymmetricKeyType() {
+      return this[kAsymmetricKeyType] ||
+             (this[kAsymmetricKeyType] = this[kHandle].getAsymmetricKeyType());
+    }
   }
-}
 
-class PublicKeyObject extends AsymmetricKeyObject {
-  constructor(handle) {
-    super('public', handle);
-  }
+  class PublicKeyObject extends AsymmetricKeyObject {
+    constructor(handle) {
+      super('public', handle);
+    }
 
-  export(encoding) {
-    const {
-      format,
-      type
-    } = parsePublicKeyEncoding(encoding, this.asymmetricKeyType);
-    return this[kHandle].export(format, type);
+    export(encoding) {
+      const {
+        format,
+        type
+      } = parsePublicKeyEncoding(encoding, this.asymmetricKeyType);
+      return this[kHandle].export(format, type);
+    }
   }
-}
 
-class PrivateKeyObject extends AsymmetricKeyObject {
-  constructor(handle) {
-    super('private', handle);
-  }
+  class PrivateKeyObject extends AsymmetricKeyObject {
+    constructor(handle) {
+      super('private', handle);
+    }
 
-  export(encoding) {
-    const {
-      format,
-      type,
-      cipher,
-      passphrase
-    } = parsePrivateKeyEncoding(encoding, this.asymmetricKeyType);
-    return this[kHandle].export(format, type, cipher, passphrase);
+    export(encoding) {
+      const {
+        format,
+        type,
+        cipher,
+        passphrase
+      } = parsePrivateKeyEncoding(encoding, this.asymmetricKeyType);
+      return this[kHandle].export(format, type, cipher, passphrase);
+    }
   }
-}
+
+  return [KeyObject, SecretKeyObject, PublicKeyObject, PrivateKeyObject];
+});
 
 function parseKeyFormat(formatStr, defaultFormat, optionName) {
   if (formatStr === undefined && defaultFormat !== undefined)

src/node_crypto.cc

@@ -3430,6 +3430,31 @@ MaybeLocal<Value> KeyObjectHandle::ExportPrivateKey(
   return WritePrivateKey(env(), asymmetric_key_.get(), config);
 }
 
+void NativeKeyObject::New(const FunctionCallbackInfo<Value>& args) {
+  CHECK_EQ(args.Length(), 0);
+}
+
+static void CreateNativeKeyObjectClass(
+    const FunctionCallbackInfo<Value>& args) {
+  Environment* env = Environment::GetCurrent(args);
+
+  CHECK_EQ(args.Length(), 1);
+  Local<Value> callback = args[0];
+  CHECK(callback->IsFunction());
+
+  Local<FunctionTemplate> t = env->NewFunctionTemplate(NativeKeyObject::New);
+  t->InstanceTemplate()->SetInternalFieldCount(
+      KeyObjectHandle::kInternalFieldCount);
+
+  Local<Value> ctor = t->GetFunction(env->context()).ToLocalChecked();
+
+  Local<Value> recv = Undefined(env->isolate());
+  Local<Value> ret =
+      callback.As<Function>()->Call(env->context(), recv, 1, &ctor)
+      .ToLocalChecked();
+  args.GetReturnValue().Set(ret);
+}
+
 CipherBase::CipherBase(Environment* env,
                        Local<Object> wrap,
                        CipherKind kind)
@@ -6901,6 +6926,8 @@ void Initialize(Local<Object> target,
   SecureContext::Initialize(env, target);
   env->set_crypto_key_object_handle_constructor(
       KeyObjectHandle::Initialize(env, target));
+  env->SetMethod(target, "createNativeKeyObjectClass",
+                 CreateNativeKeyObjectClass);
   CipherBase::Initialize(env, target);
   DiffieHellman::Initialize(env, target);
   ECDH::Initialize(env, target);

src/node_crypto.h

@@ -462,6 +462,15 @@ class KeyObjectHandle : public BaseObject {
   ManagedEVPPKey asymmetric_key_;
 };
 
+class NativeKeyObject : public BaseObject {
+ public:
+  static void New(const v8::FunctionCallbackInfo<v8::Value>& args);
+
+  SET_NO_MEMORY_INFO()
+  SET_MEMORY_INFO_NAME(NativeKeyObject)
+  SET_SELF_SIZE(NativeKeyObject)
+};
+
 class CipherBase : public BaseObject {
  public:
   static void Initialize(Environment* env, v8::Local<v8::Object> target);