Added histogram on successful check. Safe verification

chrome/browser/protector/protector.cc

 // Copyright (c) 2011 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/protector/protector.h"
 
 #include "base/logging.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/protector/settings_change_global_error.h"
 #include "chrome/browser/protector/keys.h"
@@ skipping 51 matching lines @@
   SettingChangeVector* changes = error_->mutable_changes();
   for (SettingChangeVector::iterator it = changes->begin();
        it != changes->end(); ++it)
     ((*it)->*action)(this);
   BrowserThread::DeleteSoon(BrowserThread::UI, FROM_HERE, this);
 }
 
 
 std::string SignSetting(const std::string& value) {
   crypto::HMAC hmac(crypto::HMAC::SHA256);
-  DCHECK(hmac.Init(kProtectorSigningKey));
+  if (!hmac.Init(kProtectorSigningKey)) {
+    LOG(WARNING) << "Failed to initialize HMAC algorithm for signing";

[Ilya Sherman, 2011/11/01 18:19:11]

Are you sure you want LOG(WARNING) here rather than NOTREACHED()?  Are you
expecting this to fail in builds that we ship to users; and if so, are you
expecting the logged lines to be helpful in resolving the issue?

[whywhat, 2011/11/02 08:14:29]

HMAC implementation is platform dependent so may certainly fail on user's
machines. Logging would help to identify this cases when figuring out why
Protector bubble shows up without obvious reason.  

+    return std::string();
+  }
 
   std::vector<unsigned char> digest(hmac.DigestLength());
-  DCHECK(hmac.Sign(value, &digest[0], digest.size()));
+  if (!hmac.Sign(value, &digest[0], digest.size())) {
+    LOG(WARNING) << "Failed to sign setting";
+    return std::string();
+  }
 
   return std::string(&digest[0], &digest[0] + digest.size());
 }
 
+bool IsSettingValid(const std::string& value, const std::string& signature) {
+  crypto::HMAC hmac(crypto::HMAC::SHA256);
+  if (!hmac.Init(kProtectorSigningKey)) {
+    LOG(WARNING) << "Failed to initialize HMAC algorithm for verification.";
+    return false;
+  }
+  return hmac.Verify(value, signature);
+}
+
 }  // namespace protector