Enforce variations signature verification.

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"
 
 class PrefService;
 class PrefRegistrySimple;
 
 namespace chrome_variations {
 
 class VariationsSeed;
 
 // VariationsSeedStore is a helper class for reading and writing the variations
@@ skipping 17 matching lines @@
                      const base::Time& 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);
 
+ 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();
 
   // 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_