Check the size of ResourceRecords in ServiceWorkerDatabase::ReadRegistration()

content/browser/service_worker/service_worker_database.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/service_worker/service_worker_database.h"
 
 #include "base/files/file_util.h"
 #include "base/location.h"
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
@@ skipping 512 matching lines @@
 
   RegistrationData value;
   status = ReadRegistrationData(registration_id, origin, &value);
   if (status != STATUS_OK)
     return status;
 
   status = ReadResourceRecords(value.version_id, resources);
   if (status != STATUS_OK)
     return status;
 
+  // ResourceRecord must contain the ServiceWorker's main script.
+  if (resources->empty())
+    return ServiceWorkerDatabase::STATUS_ERROR_CORRUPTED;
+
   *registration = value;
   return STATUS_OK;
 }
 
 ServiceWorkerDatabase::Status ServiceWorkerDatabase::ReadRegistrationOrigin(
     int64 registration_id,
     GURL* origin) {
   DCHECK(sequence_checker_.CalledOnValidSequencedThread());
   DCHECK(origin);
 
@@ skipping 25 matching lines @@
   return STATUS_OK;
 }
 
 ServiceWorkerDatabase::Status ServiceWorkerDatabase::WriteRegistration(
     const RegistrationData& registration,
     const std::vector<ResourceRecord>& resources,
     RegistrationData* old_registration,
     std::vector<int64>* newly_purgeable_resources) {
   DCHECK(sequence_checker_.CalledOnValidSequencedThread());
   DCHECK(old_registration);
+  DCHECK(!resources.empty());

[michaeln, 2015/05/08 20:41:08]

Should an attempt to write a reg with an empty resource list return an error? Do
we know w/o a doubt that we're not somehow writing registrations with an emtpy
resource list?

[horo, 2015/05/11 03:10:20]

When WriteRegistration() is called, the registration must have at least one
resource.
It is because ServiceWorkerDatabase::WriteRegistration() is called from
ServiceWorkerStorage::StoreRegistration() which is called after the
ServiceWorker in installed.
While the ServiceWorker is being installed the resource for the main script must
be added to ResourceMap.

Is my understanding incorrect?

   Status status = LazyOpen(true);
   old_registration->version_id = kInvalidServiceWorkerVersionId;
   if (status != STATUS_OK)
     return status;
 
   leveldb::WriteBatch batch;
   BumpNextRegistrationIdIfNeeded(registration.registration_id, &batch);
   BumpNextVersionIdIfNeeded(registration.version_id, &batch);
 
   PutUniqueOriginToBatch(registration.scope.GetOrigin(), &batch);
@@ skipping 859 matching lines @@
 
 void ServiceWorkerDatabase::HandleWriteResult(
     const tracked_objects::Location& from_here,
     Status status) {
   if (status != STATUS_OK)
     Disable(from_here, status);
   ServiceWorkerMetrics::CountWriteDatabaseResult(status);
 }
 
 }  // namespace content