callFunction argument validation (realm#4626)

* Add regression test

* Add validation for bson array.

src/js_user.hpp

@@ -31,9 +31,11 @@
 #include <realm/object-store/sync/sync_session.hpp>
 #include <realm/object-store/sync/sync_user.hpp>
 #include <realm/object-store/sync/app.hpp>
+#include <realm/object-store/util/bson/bson.hpp>
 #include "js_types.hpp"
 #include "platform.hpp"
 
+
 namespace realm {
 namespace js {
 
@@ -409,6 +411,7 @@ void UserClass<T>::call_function(ContextType ctx, ObjectType this_object, Argume
  auto user = get_internal<T, UserClass<T>>(ctx, this_object);
 
  auto name = Value::validated_to_string(ctx, args[0], "name");
+
  auto stringified_ejson_args = Value::validated_to_string(ctx, args[1], "args");
  auto service = Value::is_undefined(ctx, args[2])
  ? util::none
@@ -417,6 +420,10 @@ void UserClass<T>::call_function(ContextType ctx, ObjectType this_object, Argume
 
  auto bson_args = String::to_bson(stringified_ejson_args);
 
+ if (bson_args.type() != realm::bson::Bson::Type::Array) {
+ throw TypeErrorException("args", "array", stringified_ejson_args);
+ }
+
  user->m_app->call_function(
  user->m_user, name, static_cast<const bson::BsonArray&>(bson_args), service,
  Function::wrap_callback_result_first(ctx, this_object, callback,

tests/js/user-tests.js

@@ -348,6 +348,9 @@ module.exports = {
 
  const err = await TestCase.assertThrowsAsync(async () => await user.functions.error());
  TestCase.assertEqual(err.message, "function not found: 'error'");
+
+ // Regression tests for invalid inputs to function (non array)
+ TestCase.assertThrowsAsync(async () => await user.callFunction("sumFunc", 123));
  },
 
  async testMongoClient() {