Added incident report for variations seed signature mismatch.

chrome/browser/metrics/variations/variations_seed_store.h

 // 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.
 
 #ifndef CHROME_BROWSER_METRICS_VARIATIONS_VARIATIONS_SEED_STORE_H_
 #define CHROME_BROWSER_METRICS_VARIATIONS_VARIATIONS_SEED_STORE_H_
 
 #include <string>
 
 #include "base/compiler_specific.h"
 #include "base/gtest_prod_util.h"
 #include "base/time/time.h"
+#include "chrome/browser/safe_browsing/incident_reporting/add_incident_callback.h"

[grt (UTC plus 2), 2014/10/10 17:45:42]

remove these

[Georges Khalil, 2014/10/10 20:19:31]

Done.

+#include "chrome/browser/safe_browsing/safe_browsing_service.h"
 
 class PrefService;
 class PrefRegistrySimple;
 
 namespace variations {
 class VariationsSeed;
 }
 
 namespace chrome_variations {
 
@@ skipping 25 matching lines @@
   void UpdateSeedDateAndLogDayChange(const base::Time& server_date_fetched);
 
   // Returns the serial number of the last loaded or stored seed.
   const std::string& variations_serial_number() const {
     return variations_serial_number_;
   }
 
   // Registers Local State prefs used by this class.
   static void RegisterPrefs(PrefRegistrySimple* registry);
 
+  // Returns the bad signature that was loaded from the config or an empty

[grt (UTC plus 2), 2014/10/10 17:45:42]

using the empty string like this overloads these cases:
- signature was valid
- signature verification is disabled
- signature value was expected but missing (VARIATIONS_SEED_SIGNATURE_MISSING)
this last case should result in a report being sent, so i think you need an
additional piece of state to disambiguate.

[Georges Khalil, 2014/10/10 20:19:31]

This is by design. We only want a report if the signature is invalid for now.

[grt (UTC plus 2), 2014/10/14 01:28:29]

Acknowledged.

+  // string if not the case. Used to send an incident report.

[grt (UTC plus 2), 2014/10/10 17:45:42]

omit " Used to send an incident report." since this comment will become stale if
another consumer comes around.

[Georges Khalil, 2014/10/10 20:19:31]

Done.

+  std::string GetBadSignature() const { return bad_signature_; }

[grt (UTC plus 2), 2014/10/10 17:45:42]

imo, "invalid" is better than "bad" for the function, doc, and variable name.

[Georges Khalil, 2014/10/10 20:19:31]

Done.

+
  protected:
   // Note: UMA histogram enum - don't re-order or remove entries.
   enum VerifySignatureResult {
     VARIATIONS_SEED_SIGNATURE_MISSING,
     VARIATIONS_SEED_SIGNATURE_DECODE_FAILED,
     VARIATIONS_SEED_SIGNATURE_INVALID_SIGNATURE,
     VARIATIONS_SEED_SIGNATURE_INVALID_SEED,
     VARIATIONS_SEED_SIGNATURE_VALID,
     VARIATIONS_SEED_SIGNATURE_ENUM_SIZE,
   };
 
   // Verifies a variations seed (the serialized proto bytes) with the specified
   // base-64 encoded signature that was received from the server and returns the
   // result. The signature is assumed to be an "ECDSA with SHA-256" signature
   // (see kECDSAWithSHA256AlgorithmID in the .cc file). Returns the result of
   // signature verification or VARIATIONS_SEED_SIGNATURE_ENUM_SIZE if signature
   // verification is not enabled.
   virtual VariationsSeedStore::VerifySignatureResult VerifySeedSignature(
       const std::string& seed_bytes,
       const std::string& base64_seed_signature);
 
  private:
   FRIEND_TEST_ALL_PREFIXES(VariationsSeedStoreTest, VerifySeedSignature);
 
   // Clears all prefs related to variations seed storage.
   void ClearPrefs();
 
+  // Keeps track of a bad signature.
+  std::string bad_signature_;
+
   // The pref service used to persist the variations seed.
   PrefService* local_state_;
 
   // Cached serial number from the most recently fetched variations seed.
   std::string variations_serial_number_;
 
   DISALLOW_COPY_AND_ASSIGN(VariationsSeedStore);
 };
 
 }  // namespace chrome_variations
 
 #endif  // CHROME_BROWSER_METRICS_VARIATIONS_VARIATIONS_SEED_STORE_H_