Third Party authentication protocol.

remoting/protocol/third_party_host_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_HOST_AUTHENTICATOR_H_
+#define REMOTING_PROTOCOL_THIRD_PARTY_HOST_AUTHENTICATOR_H_
+
+#include <string>
+
+#include "base/callback.h"
+#include "base/memory/scoped_ptr.h"
+#include "googleurl/src/gurl.h"
+#include "remoting/protocol/third_party_authenticator_base.h"
+
+namespace remoting {
+
+class RsaKeyPair;
+
+namespace protocol {
+
+// Implements the host side of the third party authentication mechanism.
+// The host authenticator sends the |token_url| and |scope| obtained from the
+// |TokenValidator| to the client, and expects a |token| in response.
+// Once that token is received, it calls |TokenValidator| asynchronously to
+// validate it, and exchange it for a |shared_secret|. Once the |TokenValidator|
+// returns, the host uses the |shared_secret| to create an underlying
+// |V2Authenticator|, which is used to establish the encrypted connection.
+class ThirdPartyHostAuthenticator : public ThirdPartyAuthenticatorBase {
+ public:
+  class TokenValidator {
+   public:
+    // Callback passed to |ValidateThirdPartyToken|, and called once the host
+    // authentication finishes. |shared_secret| should be used by the host to
+    // create a V2Authenticator. In case of failure, the callback is called with
+    // an empty |shared_secret|.
+    typedef base::Callback<void(
+                const std::string& shared_secret)> TokenValidatedCallback;
+
+    virtual ~TokenValidator() {}
+
+    // Validates |token| with the server and exchanges it for a |shared_secret|.
+    // |token_validated_callback| is called when the host authentication ends,
+    // in the same thread |ValidateThirdPartyToken| was originally called.
+    // The request is canceled if this object is destroyed.
+    virtual void ValidateThirdPartyToken(
+        const std::string& token,
+        const TokenValidatedCallback& token_validated_callback) = 0;
+
+    // URL sent to the client, to be used by its |TokenFetcher| to get a token.
+    virtual const GURL& token_url() const = 0;
+
+    // Space-separated list of connection attributes the host must send to the
+    // client, and require the token received in response to match.
+    virtual const std::string& token_scope() const = 0;
+  };
+
+  // Creates a third-party host authenticator. |local_cert| and |key_pair| are
+  // used by the underlying V2Authenticator to create the SSL channels.
+  // |token_validator| contains the token parameters to be sent to the client
+  // and is used to obtain the shared secret.
+  ThirdPartyHostAuthenticator(const std::string& local_cert,
+                              scoped_refptr<RsaKeyPair> key_pair,
+                              scoped_ptr<TokenValidator> token_validator);
+  virtual ~ThirdPartyHostAuthenticator();
+
+ 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 OnThirdPartyTokenValidated(const buzz::XmlElement* message,
+                                  const base::Closure& resume_callback,
+                                  const std::string& shared_secret);
+
+  std::string local_cert_;
+  scoped_refptr<RsaKeyPair> key_pair_;
+  scoped_ptr<TokenValidator> token_validator_;
+};
+
+}  // namespace protocol
+}  // namespace remoting
+
+#endif  // REMOTING_PROTOCOL_THIRD_PARTY_HOST_AUTHENTICATOR_H_