Third Party authentication protocol.

remoting/protocol/third_party_client_authenticator.h

+// Copyright 2013 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 REMOTING_PROTOCOL_THIRD_PARTY_CLIENT_AUTHENTICATOR_H_
+#define REMOTING_PROTOCOL_THIRD_PARTY_CLIENT_AUTHENTICATOR_H_
+
+#include <string>
+
+#include "base/callback.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
+#include "remoting/protocol/third_party_authenticator_base.h"
+
+class GURL;
+
+namespace remoting {
+namespace protocol {
+
+// Implements an authentication method that relies on a third party server for
+// authentication of both client and host.
+// When third party authentication is being used, the client must request both a
+// token and a shared secret from a third-party server (which may require the
+// user to authenticate themselves). The client then sends only the token to the
+// host. The host signs the token, then contacts the third-party server to
+// exchange the token for the shared secret. Once both client and host have the
+// shared secret, they use an underlying |V2Authenticator| (SPAKE2) to negotiate
+// an authentication key, which is used to establish the connection.

[Wez, 2013/03/22 06:17:01]

Isn't this comment already present on the ThirdPartyAuthenticatorBase?

[rmsousa, 2013/03/22 21:19:05]

Indeed, changed for a client specific comment.

+class ThirdPartyClientAuthenticator : public ThirdPartyAuthenticatorBase {
+ public:
+  class TokenFetcher {
+   public:
+    // Callback passed to |FetchThirdPartyToken|, and called once the client
+    // authentication finishes. |token| is an opaque string that should be sent
+    // directly to the host. |shared_secret| should be used by the client to
+    // create a V2Authenticator. In case of failure, the callback is called with
+    // an empty |token| and |shared_secret|.
+    typedef base::Callback<void(
+        const std::string& token,
+        const std::string& shared_secret)> TokenFetchedCallback;
+
+    virtual ~TokenFetcher() {}
+
+    // Fetches a third party token from |token_url|. |host_public_key| is sent
+    // to the server so it can later authenticate the host. |scope| is a string
+    // with a space-separated list of attributes for this connection (e.g.
+    // "hostjid:abc@example.com/123 clientjid:def@example.org/456".
+    // |token_fetched_callback| is called when the client authentication ends,
+    // in the same thread |FetchThirdPartyToken| was originally called.
+    // The request is canceled if the TokenFetcher is destroyed.
+    virtual void FetchThirdPartyToken(
+        const GURL& token_url,
+        const std::string& host_public_key,
+        const std::string& scope,
+        const TokenFetchedCallback& token_fetched_callback) = 0;
+  };
+
+  // Creates a third-party client authenticator, for the host with the given

[Wez, 2013/03/22 06:17:01]

nit: remove comma

[rmsousa, 2013/03/22 21:19:05]

Done.

+  // |host_public_key|. |token_fetcher| is used to get the authentication token.
+  ThirdPartyClientAuthenticator(const std::string& host_public_key,
+                                scoped_ptr<TokenFetcher> token_fetcher);
+  virtual ~ThirdPartyClientAuthenticator();
+
+ protected:
+  // ThirdPartyAuthenticator implementation.
+  virtual void ProcessTokenMessage(
+      const buzz::XmlElement* message,
+      const base::Closure& resume_callback) OVERRIDE;
+  virtual void AddTokenElements(buzz::XmlElement* message) OVERRIDE;
+
+ private:
+  void OnThirdPartyTokenFetched(const base::Closure& resume_callback,
+                                const std::string& third_party_token,
+                                const std::string& shared_secret);
+
+  std::string host_public_key_;
+  std::string token_;
+  scoped_ptr<TokenFetcher> token_fetcher_;
+
+  DISALLOW_COPY_AND_ASSIGN(ThirdPartyClientAuthenticator);
+};
+
+
+}  // namespace protocol
+}  // namespace remoting
+
+#endif  // REMOTING_PROTOCOL_THIRD_PARTY_CLIENT_AUTHENTICATOR_H_