Added incident report for variations seed signature mismatch.

chrome/browser/metrics/variations/variations_seed_store.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 "chrome/browser/metrics/variations/variations_seed_store.h"
 
 #include "base/base64.h"
 #include "base/metrics/histogram.h"
 #include "base/prefs/pref_registry_simple.h"
 #include "base/prefs/pref_service.h"
 #include "base/sha1.h"
 #include "base/strings/string_number_conversions.h"
+#include "chrome/browser/browser_process.h"

[grt (UTC plus 2), 2014/10/14 01:28:30]

unused

[Georges Khalil, 2014/10/14 13:51:09]

Done.

 #include "chrome/common/pref_names.h"
 #include "components/variations/proto/variations_seed.pb.h"
 #include "crypto/signature_verifier.h"
 
 namespace chrome_variations {
 
 namespace {
 
 // Signature verification is disabled on mobile platforms for now, since it
 // adds about ~15ms to the startup time on mobile (vs. a couple ms on desktop).
@@ skipping 83 matching lines @@
     // The server date is earlier than the stored date, and they are from
     // different UTC days, so |server_seed_date| is a valid new day.
     return SEED_DATE_NEW_DAY;
   }
   return SEED_DATE_SAME_DAY;
 }
 
 }  // namespace
 
 VariationsSeedStore::VariationsSeedStore(PrefService* local_state)
     : local_state_(local_state) {

[grt (UTC plus 2), 2014/10/14 01:28:30]

the new bool must be initialized:
    : is_invalid_signature(), local_state_(local_state) {

[Georges Khalil, 2014/10/14 13:51:09]

Done.

 }
 
 VariationsSeedStore::~VariationsSeedStore() {
 }
 
 bool VariationsSeedStore::LoadSeed(variations::VariationsSeed* seed) {
+  invalid_signature_.clear();
+  is_invalid_signature_ = false;
   const std::string base64_seed_data =
       local_state_->GetString(prefs::kVariationsSeed);
   if (base64_seed_data.empty()) {
     RecordVariationSeedEmptyHistogram(VARIATIONS_SEED_EMPTY);
     return false;
   }
 
   // If the decode process fails, assume the pref value is corrupt and clear it.
   std::string seed_data;
   if (!base::Base64Decode(base64_seed_data, &seed_data) ||
@@ skipping 10 matching lines @@
   const VerifySignatureResult result =
       VerifySeedSignature(seed_data, base64_seed_signature);
   if (result != VARIATIONS_SEED_SIGNATURE_ENUM_SIZE) {
     UMA_HISTOGRAM_ENUMERATION("Variations.LoadSeedSignature", result,
                               VARIATIONS_SEED_SIGNATURE_ENUM_SIZE);
     if (result != VARIATIONS_SEED_SIGNATURE_VALID) {
       VLOG(1) << "Variations seed signature in local pref missing or invalid "
               << "with result: " << result << ". Clearing the pref.";
       ClearPrefs();
       RecordVariationSeedEmptyHistogram(VARIATIONS_SEED_INVALID_SIGNATURE);
+      // Record the invalid signature.
+      is_invalid_signature_ = true;
+      invalid_signature_ = base64_seed_signature;
       return false;
     }
   }
 
   variations_serial_number_ = seed->serial_number();
   RecordVariationSeedEmptyHistogram(VARIATIONS_SEED_NOT_EMPTY);
   return true;
 }
 
 bool VariationsSeedStore::StoreSeedData(
@@ skipping 102 matching lines @@
     return VARIATIONS_SEED_SIGNATURE_INVALID_SIGNATURE;
   }
 
   verifier.VerifyUpdate(reinterpret_cast<const uint8*>(seed_bytes.data()),
                         seed_bytes.size());
   if (verifier.VerifyFinal())
     return VARIATIONS_SEED_SIGNATURE_VALID;
   return VARIATIONS_SEED_SIGNATURE_INVALID_SEED;
 }
 
+bool VariationsSeedStore::GetInvalidSignature(
+    std::string* invalid_signature) const {
+  if (!is_invalid_signature_) {
+    return false;
+  }
+  *invalid_signature = invalid_signature_;
+  return true;
+}
+
 }  // namespace chrome_variations