From 68960eeb763f93dcedb37d5b663b1019192b7f36 Mon Sep 17 00:00:00 2001
From: jbroman <jbroman@chromium.org>
Date: Thu, 23 Feb 2017 05:23:00 -0800
Subject: [PATCH] ValueDeserializer: Make sure that an exception is the legacy
 path.

The entry points to the deserializer are responsible for ensuring that an
exception is pending by the time they return. Some failures throw exceptions
themselves, while others (like errors in the format) are exceptions caused by
the deserializer, not coming from the runtime.

Like the non-legacy path, a default deserialization exception should be thrown
in such cases.

BUG=chromium:693411

Review-Url: https://codereview.chromium.org/2712713002
Cr-Commit-Position: refs/heads/master@{#43390}
---
 src/value-serializer.cc | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/src/value-serializer.cc b/src/value-serializer.cc
index 7752a47efa..79e2b7382a 100644
--- a/src/value-serializer.cc
+++ b/src/value-serializer.cc
@@ -1849,6 +1849,20 @@ static Maybe<bool> SetPropertiesFromKeyValuePairs(Isolate* isolate,
   return Just(true);
 }
 
+namespace {
+
+// Throws a generic "deserialization failed" exception by default, unless a more
+// specific exception has already been thrown.
+void ThrowDeserializationExceptionIfNonePending(Isolate* isolate) {
+  if (!isolate->has_pending_exception()) {
+    isolate->Throw(*isolate->factory()->NewError(
+        MessageTemplate::kDataCloneDeserializationError));
+  }
+  DCHECK(isolate->has_pending_exception());
+}
+
+}  // namespace
+
 MaybeHandle<Object>
 ValueDeserializer::ReadObjectUsingEntireBufferForLegacyFormat() {
   DCHECK_EQ(version_, 0u);
@@ -1881,7 +1895,7 @@ ValueDeserializer::ReadObjectUsingEntireBufferForLegacyFormat() {
             !SetPropertiesFromKeyValuePairs(
                  isolate_, js_object, &stack[begin_properties], num_properties)
                  .FromMaybe(false)) {
-          DCHECK(isolate_->has_pending_exception());
+          ThrowDeserializationExceptionIfNonePending(isolate_);
           return MaybeHandle<Object>();
         }
 
@@ -1912,7 +1926,7 @@ ValueDeserializer::ReadObjectUsingEntireBufferForLegacyFormat() {
             !SetPropertiesFromKeyValuePairs(
                  isolate_, js_array, &stack[begin_properties], num_properties)
                  .FromMaybe(false)) {
-          DCHECK(isolate_->has_pending_exception());
+          ThrowDeserializationExceptionIfNonePending(isolate_);
           return MaybeHandle<Object>();
         }