Fix out-of-bounds access in fetching propery names

src/runtime.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 4565 matching lines @@
     }
   }
 
   // Allocate an array with storage for all the property names.
   Handle<FixedArray> names =
       isolate->factory()->NewFixedArray(total_property_count);
 
   // Get the property names.
   jsproto = obj;
   int proto_with_hidden_properties = 0;
+  int next_copy_index = 0;
   for (int i = 0; i < length; i++) {
-    jsproto->GetLocalPropertyNames(*names,
-                                   i == 0 ? 0 : local_property_count[i - 1]);
+    jsproto->GetLocalPropertyNames(*names, next_copy_index);
+    next_copy_index += local_property_count[i];
     if (jsproto->HasHiddenProperties()) {
       proto_with_hidden_properties++;
     }
     if (i < length - 1) {
       jsproto = Handle<JSObject>(JSObject::cast(jsproto->GetPrototype()));
     }
   }
 
   // Filter out name of hidden propeties object.
   if (proto_with_hidden_properties > 0) {
@@ skipping 8222 matching lines @@
   } else {
     // Handle last resort GC and make sure to allow future allocations
     // to grow the heap without causing GCs (if possible).
     isolate->counters()->gc_last_resort_from_js()->Increment();
     isolate->heap()->CollectAllGarbage(false);
   }
 }
 
 
 } }  // namespace v8::internal