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- // 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.
- #ifndef REMOTING_PROTOCOL_AUTHENTICATOR_H_
- #define REMOTING_PROTOCOL_AUTHENTICATOR_H_
- #include <memory>
- #include <string>
- #include "base/callback_forward.h"
- namespace jingle_xmpp {
- class XmlElement;
- } // namespace jingle_xmpp
- namespace remoting {
- namespace protocol {
- class Authenticator;
- class ChannelAuthenticator;
- // Authenticator is an abstract interface for authentication protocol
- // implementations. Different implementations of this interface may be used on
- // each side of the connection depending of type of the auth protocol. Client
- // and host will repeatedly call their Authenticators and deliver the messages
- // they generate, until successful authentication is reported.
- //
- // Authenticator may exchange multiple messages before session is authenticated.
- // Each message sent/received by an Authenticator is delivered either in a
- // session description inside session-initiate and session-accept messages or in
- // a session-info message. Session-info messages are used only if authenticators
- // need to exchange more than one message.
- class Authenticator {
- public:
- // Allowed state transitions:
- // When ProcessMessage() is called:
- // WAITING_MESSAGE -> MESSAGE_READY
- // WAITING_MESSAGE -> ACCEPTED
- // WAITING_MESSAGE -> REJECTED
- // WAITING_MESSAGE -> PROCESSING_MESSAGE
- // After asynchronous message processing finishes:
- // PROCESSING_MESSAGE -> MESSAGE_READY
- // PROCESSING_MESSAGE -> ACCEPTED
- // PROCESSING_MESSAGE -> REJECTED
- // When GetNextMessage() is called:
- // MESSAGE_READY -> WAITING_MESSAGE
- // MESSAGE_READY -> ACCEPTED
- enum State {
- // Waiting for the next message from the peer.
- WAITING_MESSAGE,
- // Next message is ready to be sent to the peer.
- MESSAGE_READY,
- // Session is authenticated successfully.
- ACCEPTED,
- // Session is rejected.
- REJECTED,
- // Asynchronously processing the last message from the peer.
- PROCESSING_MESSAGE,
- };
- enum class RejectionReason {
- // The account credentials were not valid (i.e. incorrect PIN).
- INVALID_CREDENTIALS,
- // The client JID was not valid (i.e. violated a policy or was malformed).
- INVALID_ACCOUNT_ID,
- // Generic error used when something goes wrong establishing a session.
- PROTOCOL_ERROR,
- // Session was rejected by the user (i.e. via the confirmation dialog).
- REJECTED_BY_USER,
- // Multiple, valid connection requests were received for the same session.
- TOO_MANY_CONNECTIONS,
- // The client is not authorized to connect to this device due to a policy
- // defined by the third party auth service. No denial reason was given.
- AUTHZ_POLICY_CHECK_FAILED,
- // The client is not authorized to connect to this device based on their
- // current location due to a policy defined by the third party auth service.
- LOCATION_AUTHZ_POLICY_CHECK_FAILED,
- };
- // Callback used for layered Authenticator implementations, particularly
- // third-party and pairing authenticators. They use this callback to create
- // base SPAKE2 authenticators.
- typedef base::RepeatingCallback<std::unique_ptr<Authenticator>(
- const std::string& shared_secret,
- Authenticator::State initial_state)>
- CreateBaseAuthenticatorCallback;
- // Returns true if |message| is an Authenticator message.
- static bool IsAuthenticatorMessage(const jingle_xmpp::XmlElement* message);
- // Creates an empty Authenticator message, owned by the caller.
- static std::unique_ptr<jingle_xmpp::XmlElement> CreateEmptyAuthenticatorMessage();
- // Finds Authenticator message among child elements of |message|, or
- // returns nullptr otherwise.
- static const jingle_xmpp::XmlElement* FindAuthenticatorMessage(
- const jingle_xmpp::XmlElement* message);
- Authenticator() {}
- virtual ~Authenticator() {}
- // Returns current state of the authenticator.
- virtual State state() const = 0;
- // Returns whether authentication has started. The chromoting host uses this
- // method to start the back off process to prevent malicious clients from
- // guessing the PIN by spamming the host with auth requests.
- virtual bool started() const = 0;
- // Returns rejection reason. Can be called only when in REJECTED state.
- virtual RejectionReason rejection_reason() const = 0;
- // Called in response to incoming message received from the peer.
- // Should only be called when in WAITING_MESSAGE state. Caller retains
- // ownership of |message|. |resume_callback| will be called when processing is
- // finished. The implementation must guarantee that |resume_callback| is not
- // called after the Authenticator is destroyed.
- virtual void ProcessMessage(const jingle_xmpp::XmlElement* message,
- base::OnceClosure resume_callback) = 0;
- // Must be called when in MESSAGE_READY state. Returns next
- // authentication message that needs to be sent to the peer.
- virtual std::unique_ptr<jingle_xmpp::XmlElement> GetNextMessage() = 0;
- // Returns the auth key received as result of the authentication handshake.
- virtual const std::string& GetAuthKey() const = 0;
- // Creates new authenticator for a channel. Can be called only in
- // the ACCEPTED state.
- virtual std::unique_ptr<ChannelAuthenticator> CreateChannelAuthenticator()
- const = 0;
- };
- // Factory for Authenticator instances.
- class AuthenticatorFactory {
- public:
- AuthenticatorFactory() {}
- virtual ~AuthenticatorFactory() {}
- // Called when session-initiate stanza is received to create
- // authenticator for the new session. |first_message| specifies
- // authentication part of the session-initiate stanza so that
- // appropriate type of Authenticator can be chosen for the session
- // (useful when multiple authenticators are supported). Returns nullptr
- // if the |first_message| is invalid and the session should be
- // rejected. ProcessMessage() should be called with |first_message|
- // for the result of this method.
- virtual std::unique_ptr<Authenticator> CreateAuthenticator(
- const std::string& local_jid,
- const std::string& remote_jid) = 0;
- };
- } // namespace protocol
- } // namespace remoting
- #endif // REMOTING_PROTOCOL_AUTHENTICATOR_H_
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