Eliminate CHECK from CryptohomeLibrary::LoadSystemSalt

chrome/browser/chromeos/login/parallel_authenticator.cc

 // Copyright (c) 2012 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/chromeos/login/parallel_authenticator.h"
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/files/file_path.h"
 #include "base/logging.h"
@@ skipping 169 matching lines @@
       attempt->user_context.username,
       attempt->ascii_hash,
       base::Bind(&TriggerResolve, attempt, resolver));
 }
 
 // Returns hash of |password|, salted with the system salt.
 std::string HashPassword(const std::string& password) {
   // Get salt, ascii encode, update sha with that, then update with ascii
   // of password, then end.
   std::string ascii_salt = CryptohomeLibrary::Get()->GetSystemSalt();
+  // TODO(stevenjb/nkostylev): Handle empty system salt gracefully.
+  CHECK(!ascii_salt.empty());

[zel, 2013/09/20 16:28:05]

how's this helping to fix this problem?

you've just move the assert from one place to another

[stevenjb, 2013/09/20 16:42:23]

The crash we were seeing occurred because some extensions code was trying to
access system salt early. We still need to ensure that we don't try to login
without system salt. We should absolutely change this to be more robust, but
someone more familiar with the login code should do this. There's a long
standing bug to fix this, crbug.com/141009.

[zel, 2013/09/20 16:48:40]

Yes, I would rather:
a) Find out which extension is responsible for that (there are not that many of
them running at login screen) and figure out if it's really launched too early,
and
b) Revert this CL, and
c) Fix http://crbug.com/141009 properly

   char passhash_buf[kPasswordHashLength];
 
   // Hash salt and password
   crypto::SHA256HashString(ascii_salt + password,
                            &passhash_buf, sizeof(passhash_buf));
 
   // Only want the top half for 'weak' hashing so that the passphrase is not
   // immediately exposed even if the output is reversed.
   const int encoded_length = sizeof(passhash_buf) / 2;
 
@@ skipping 639 matching lines @@
   Resolve();
 }
 
 void ParallelAuthenticator::SetOwnerState(bool owner_check_finished,
                                           bool check_result) {
   owner_is_verified_ = owner_check_finished;
   user_can_login_ = check_result;
 }
 
 }  // namespace chromeos