Check username validity in the FakeAuthPolicyClient

chromeos/dbus/fake_auth_policy_client.cc

 // Copyright 2016 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 "chromeos/dbus/fake_auth_policy_client.h"
 
 #include "base/bind.h"
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/location.h"
 #include "base/md5.h"
 #include "base/path_service.h"
+#include "base/strings/string_split.h"
 #include "base/task_scheduler/post_task.h"
 #include "chrome/browser/chromeos/policy/proto/chrome_device_policy.pb.h"
 #include "chromeos/chromeos_paths.h"
 #include "chromeos/cryptohome/cryptohome_parameters.h"
 #include "chromeos/dbus/cryptohome_client.h"
 #include "components/policy/proto/cloud_policy.pb.h"
 #include "components/policy/proto/device_management_backend.pb.h"
 #include "components/signin/core/account_id/account_id.h"
 #include "third_party/cros_system_api/dbus/service_constants.h"
 
@@ skipping 35 matching lines @@
 FakeAuthPolicyClient::FakeAuthPolicyClient() {}
 
 FakeAuthPolicyClient::~FakeAuthPolicyClient() {}
 
 void FakeAuthPolicyClient::Init(dbus::Bus* bus) {}
 
 void FakeAuthPolicyClient::JoinAdDomain(const std::string& machine_name,
                                         const std::string& user_principal_name,
                                         int password_fd,
                                         const JoinCallback& callback) {
+  std::vector<std::string> parts = base::SplitString(
+      user_principal_name, "@", base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL);
+  if (parts.size() != 2U) {

[Thiemo Nagel, 2017/01/24 14:17:36]

It seems that you'll have to check the sizes of the parts as well.  I still
managed to crash Chrome by entering "a@ " as the user name.

Nit: Imho "2U" is uncommon, "2" would be easier to read.

[achuithb, 2017/01/24 19:42:11]

Sounds like we need a unit test

[Roman Sorokin (ftl), 2017/01/25 11:50:18]

Done.

[Roman Sorokin (ftl), 2017/01/25 11:50:18]

Done.

+    callback.Run(authpolicy::ERROR_PARSE_UPN_FAILED);
+    return;
+  }
+
   callback.Run(authpolicy::ERROR_NONE);
 }
 
 void FakeAuthPolicyClient::AuthenticateUser(
     const std::string& user_principal_name,
     int password_fd,
     const AuthCallback& callback) {
   callback.Run(authpolicy::ERROR_NONE, base::MD5String(user_principal_name));
 }
 
@@ skipping 46 matching lines @@
                      .WithShutdownBehavior(
                          base::TaskShutdownBehavior::CONTINUE_ON_SHUTDOWN)
                      .WithPriority(base::TaskPriority::BACKGROUND)
                      .MayBlock(),
       base::Bind(&WritePolicyFile, policy_path, payload,
                  "google/chromeos/user"),
       callback);
 }
 
 }  // namespace chromeos