/src/botan/build/include/botan/internal/tls_channel_impl.h

Source (jump to first uncovered line)
/*
* TLS Channel
* (C) 2011,2012,2014,2015 Jack Lloyd
*     2016 Matthias Gierlings
*     2021 Elektrobit Automotive GmbH
*     2022 René Meusel, Hannes Rantzsch - neXenio GmbH
*
* Botan is released under the Simplified BSD License (see license.txt)
*/

#ifndef BOTAN_TLS_CHANNEL_IMPL_H_
#define BOTAN_TLS_CHANNEL_IMPL_H_

#include <botan/tls_channel.h>
#include <botan/tls_version.h>
#include <botan/tls_magic.h>

#include <vector>
#include <memory>
#include <utility>

namespace Botan {

class Credentials_Manager;
class X509_Certificate;

namespace TLS {

class Client;
class Server;

class Channel_Impl
   {
   public:
      virtual ~Channel_Impl() = default;

      /**
      * Inject TLS traffic received from counterparty
      * @return a hint as the how many more bytes we need to q the
      *         current record (this may be 0 if on a record boundary)
      */
      virtual size_t from_peer(std::span<const uint8_t> data) = 0;

      /**
      * Inject plaintext intended for counterparty
      * Throws an exception if is_active() is false
      */
      virtual void to_peer(std::span<const uint8_t> data) = 0;

      /**
      * Send a TLS alert message. If the alert is fatal, the internal
      * state (keys, etc) will be reset.
      * @param alert the Alert to send
      */
      virtual void send_alert(const Alert& alert) = 0;

      /**
      * Send a warning alert
      */
      void send_warning_alert(Alert::Type type) { send_alert(Alert(type, false)); }

      /**
      * Send a fatal alert
      */
      void send_fatal_alert(Alert::Type type) { send_alert(Alert(type, true)); }

      /**
      * Send a close notification alert
      */
      void close() { send_warning_alert(Alert::CloseNotify); }

      /**
      * @return true iff the connection is active for sending application data
      */
      virtual bool is_active() const = 0;

      /**
      * @return true iff the connection has been definitely closed
      */
      virtual bool is_closed() const = 0;

      /**
      * @return true iff the connection is active for sending application data
      */
      virtual bool is_closed_for_reading() const = 0;

      /**
      * @return true iff the connection has been definitely closed
      */
      virtual bool is_closed_for_writing() const = 0;

      /**
      * @return certificate chain of the peer (may be empty)
      */
      virtual std::vector<X509_Certificate> peer_cert_chain() const = 0;

      /**
      * Key material export (RFC 5705)
      * @param label a disambiguating label string
      * @param context a per-association context value
      * @param length the length of the desired key in bytes
      * @return key of length bytes
      */
      virtual SymmetricKey key_material_export(const std::string& label,
                                       const std::string& context,
                                       size_t length) const = 0;

      /**
      * Attempt to renegotiate the session
      * @param force_full_renegotiation if true, require a full renegotiation,
      * otherwise allow session resumption
      */
      virtual void renegotiate(bool force_full_renegotiation = false) = 0;

      /**
      * @return true if this channel can issue TLS 1.3 style session tickets.
      */
      virtual bool new_session_ticket_supported() const { return false; }

      /**
      * Send @p tickets new session tickets to the peer. This is only supported
      * on TLS 1.3 servers.
      *
      * If the server's Session_Manager does not accept the generated Session
      * objects, the server implementation won't be able to send new tickets.
      * Additionally, anything but TLS 1.3 servers will return 0 (because they
      * don't support sending such session tickets).
      *
      * @returns the number of session tickets successfully sent to the client
      */
      virtual size_t send_new_session_tickets(const size_t /* tickets */) { return 0; }

      /**
      * Attempt to update the session's traffic key material
      * Note that this is possible with a TLS 1.3 channel, only.
      *
      * @param request_peer_update if true, require a reciprocal key update
      */
      virtual void update_traffic_keys(bool request_peer_update = false) = 0;

      /**
      * @return true iff the counterparty supports the secure
      * renegotiation extensions.
      */
      virtual bool secure_renegotiation_supported() const = 0;

      /**
      * Perform a handshake timeout check. This does nothing unless
      * this is a DTLS channel with a pending handshake state, in
      * which case we check for timeout and potentially retransmit
      * handshake packets.
      */
      virtual bool timeout_check() = 0;

      /**
      * Return the protocol notification set for this connection, if any (ALPN).
      * This value is not tied to the session and a later renegotiation of the
      * same session can choose a new protocol.
      */
      virtual std::string application_protocol() const = 0;

   protected:
      /**
       * This struct collect all information required to perform a downgrade from TLS 1.3 to TLS 1.2.
       *
       * The downgrade process is (currently) triggered when a TLS 1.3 client receives a downgrade request
       * in the server hello message (@sa `Client_Impl_13::handle(Server_Hello_12)`). As a result,
       * `Client::received_data` should detect this condition and replace its `Channel_Impl_13` member by a
       * `Channel_Impl_12`.
       *
       * Note that the downgrade process for the server implementation will likely differ.
       */
      struct Downgrade_Information
         {
         /// The client hello message including the handshake header bytes as transferred to the peer.
         std::vector<uint8_t> client_hello_message;

         /// The full data transcript received from the peer. This will contain the server hello message that forced us to downgrade.
         std::vector<uint8_t> peer_transcript;

         /// The TLS 1.2 session information found by a TLS 1.3 client that
         /// caused it to initiate a downgrade before even sending a client hello.
         std::optional<Session_with_Handle> tls12_session;

         Server_Information server_info;
         std::vector<std::string> next_protocols;
         size_t io_buffer_size;

         std::shared_ptr<Callbacks> callbacks;
         std::shared_ptr<Session_Manager> session_manager;
         std::shared_ptr<Credentials_Manager> creds;
         std::shared_ptr<RandomNumberGenerator> rng;
         std::shared_ptr<const Policy> policy;

         bool received_tls_13_error_alert;
         bool will_downgrade;
         };

      std::unique_ptr<Downgrade_Information> m_downgrade_info;

      void preserve_peer_transcript(std::span<const uint8_t> input)
         {
         BOTAN_STATE_CHECK(m_downgrade_info);
         m_downgrade_info->peer_transcript.insert(m_downgrade_info->peer_transcript.end(),
                                                  input.begin(), input.end());
         }

      void preserve_client_hello(std::span<const uint8_t> msg)
         {
         BOTAN_STATE_CHECK(m_downgrade_info);
         m_downgrade_info->client_hello_message.assign(msg.begin(), msg.end());
         }

      friend class Client;
      friend class Server;
      void set_io_buffer_size(size_t io_buf_sz)
         {
         BOTAN_STATE_CHECK(m_downgrade_info);
         m_downgrade_info->io_buffer_size = io_buf_sz;
         }

      /**
       * Implementations use this to signal that the peer indicated a protocol
       * version downgrade. After calling `request_downgrade()` no further
       * state changes must be perfomed by the implementation. Particularly, no
       * further handshake messages must be emitted. Instead, they must yield
       * control flow back to the underlying Channel implementation to perform
       * the protocol version downgrade.
       */
      void request_downgrade()
         {
         BOTAN_STATE_CHECK(m_downgrade_info && !m_downgrade_info->will_downgrade);
         m_downgrade_info->will_downgrade = true;
         }

      void request_downgrade_for_resumption(Session_with_Handle session)
         {
         BOTAN_STATE_CHECK(m_downgrade_info &&
                           m_downgrade_info->client_hello_message.empty() &&
                           m_downgrade_info->peer_transcript.empty() &&
                           !m_downgrade_info->tls12_session.has_value());
         BOTAN_ASSERT_NOMSG(session.session.version().is_pre_tls_13());
         m_downgrade_info->tls12_session = std::move(session);
         request_downgrade();
         }

   public:
      /**
       * Indicates whether a downgrade to TLS 1.2 or lower is in progress
       *
       * @sa Downgrade_Information
       */
      bool is_downgrading() const { return m_downgrade_info && m_downgrade_info->will_downgrade; }

      /**
       * @sa Downgrade_Information
       */
      std::unique_ptr<Downgrade_Information> extract_downgrade_info() { return std::exchange(m_downgrade_info, {}); }

      bool expects_downgrade() const { return m_downgrade_info != nullptr; }
   };

}

}

#endif

Coverage Report

Created: 2023-04-05 14:54

Line	Count	Source (jump to first uncovered line)
1		/*
2		* TLS Channel
3		* (C) 2011,2012,2014,2015 Jack Lloyd
4		* 2016 Matthias Gierlings
5		* 2021 Elektrobit Automotive GmbH
6		* 2022 René Meusel, Hannes Rantzsch - neXenio GmbH
7		*
8		* Botan is released under the Simplified BSD License (see license.txt)
9		*/
10
11		#ifndef BOTAN_TLS_CHANNEL_IMPL_H_
12		#define BOTAN_TLS_CHANNEL_IMPL_H_
13
14		#include <botan/tls_channel.h>
15		#include <botan/tls_version.h>
16		#include <botan/tls_magic.h>
17
18		#include <vector>
19		#include <memory>
20		#include <utility>
21
22		namespace Botan {
23
24		class Credentials_Manager;
25		class X509_Certificate;
26
27		namespace TLS {
28
29		class Client;
30		class Server;
31
32		class Channel_Impl
33		{
34		public:
35	13.1k	virtual ~Channel_Impl() = default;
36
37		/**
38		* Inject TLS traffic received from counterparty
39		* @return a hint as the how many more bytes we need to q the
40		* current record (this may be 0 if on a record boundary)
41		*/
42		virtual size_t from_peer(std::span<const uint8_t> data) = 0;
43
44		/**
45		* Inject plaintext intended for counterparty
46		* Throws an exception if is_active() is false
47		*/
48		virtual void to_peer(std::span<const uint8_t> data) = 0;
49
50		/**
51		* Send a TLS alert message. If the alert is fatal, the internal
52		* state (keys, etc) will be reset.
53		* @param alert the Alert to send
54		*/
55		virtual void send_alert(const Alert& alert) = 0;
56
57		/**
58		* Send a warning alert
59		*/
60	627	void send_warning_alert(Alert::Type type) { send_alert(Alert(type, false)); }
61
62		/**
63		* Send a fatal alert
64		*/
65	11.7k	void send_fatal_alert(Alert::Type type) { send_alert(Alert(type, true)); }
66
67		/**
68		* Send a close notification alert
69		*/
70	0	void close() { send_warning_alert(Alert::CloseNotify); }
71
72		/**
73		* @return true iff the connection is active for sending application data
74		*/
75		virtual bool is_active() const = 0;
76
77		/**
78		* @return true iff the connection has been definitely closed
79		*/
80		virtual bool is_closed() const = 0;
81
82		/**
83		* @return true iff the connection is active for sending application data
84		*/
85		virtual bool is_closed_for_reading() const = 0;
86
87		/**
88		* @return true iff the connection has been definitely closed
89		*/
90		virtual bool is_closed_for_writing() const = 0;
91
92		/**
93		* @return certificate chain of the peer (may be empty)
94		*/
95		virtual std::vector<X509_Certificate> peer_cert_chain() const = 0;
96
97		/**
98		* Key material export (RFC 5705)
99		* @param label a disambiguating label string
100		* @param context a per-association context value
101		* @param length the length of the desired key in bytes
102		* @return key of length bytes
103		*/
104		virtual SymmetricKey key_material_export(const std::string& label,
105		const std::string& context,
106		size_t length) const = 0;
107
108		/**
109		* Attempt to renegotiate the session
110		* @param force_full_renegotiation if true, require a full renegotiation,
111		* otherwise allow session resumption
112		*/
113		virtual void renegotiate(bool force_full_renegotiation = false) = 0;
114
115		/**
116		* @return true if this channel can issue TLS 1.3 style session tickets.
117		*/
118	0	virtual bool new_session_ticket_supported() const { return false; }
119
120		/**
121		* Send @p tickets new session tickets to the peer. This is only supported
122		* on TLS 1.3 servers.
123		*
124		* If the server's Session_Manager does not accept the generated Session
125		* objects, the server implementation won't be able to send new tickets.
126		* Additionally, anything but TLS 1.3 servers will return 0 (because they
127		* don't support sending such session tickets).
128		*
129		* @returns the number of session tickets successfully sent to the client
130		*/
131	0	virtual size_t send_new_session_tickets(const size_t /* tickets */) { return 0; }
132
133		/**
134		* Attempt to update the session's traffic key material
135		* Note that this is possible with a TLS 1.3 channel, only.
136		*
137		* @param request_peer_update if true, require a reciprocal key update
138		*/
139		virtual void update_traffic_keys(bool request_peer_update = false) = 0;
140
141		/**
142		* @return true iff the counterparty supports the secure
143		* renegotiation extensions.
144		*/
145		virtual bool secure_renegotiation_supported() const = 0;
146
147		/**
148		* Perform a handshake timeout check. This does nothing unless
149		* this is a DTLS channel with a pending handshake state, in
150		* which case we check for timeout and potentially retransmit
151		* handshake packets.
152		*/
153		virtual bool timeout_check() = 0;
154
155		/**
156		* Return the protocol notification set for this connection, if any (ALPN).
157		* This value is not tied to the session and a later renegotiation of the
158		* same session can choose a new protocol.
159		*/
160		virtual std::string application_protocol() const = 0;
161
162		protected:
163		/**
164		* This struct collect all information required to perform a downgrade from TLS 1.3 to TLS 1.2.
165		*
166		* The downgrade process is (currently) triggered when a TLS 1.3 client receives a downgrade request
167		* in the server hello message (@sa `Client_Impl_13::handle(Server_Hello_12)`). As a result,
168		* `Client::received_data` should detect this condition and replace its `Channel_Impl_13` member by a
169		* `Channel_Impl_12`.
170		*
171		* Note that the downgrade process for the server implementation will likely differ.
172		*/
173		struct Downgrade_Information
174		{
175		/// The client hello message including the handshake header bytes as transferred to the peer.
176		std::vector<uint8_t> client_hello_message;
177
178		/// The full data transcript received from the peer. This will contain the server hello message that forced us to downgrade.
179		std::vector<uint8_t> peer_transcript;
180
181		/// The TLS 1.2 session information found by a TLS 1.3 client that
182		/// caused it to initiate a downgrade before even sending a client hello.
183		std::optional<Session_with_Handle> tls12_session;
184
185		Server_Information server_info;
186		std::vector<std::string> next_protocols;
187		size_t io_buffer_size;
188
189		std::shared_ptr<Callbacks> callbacks;
190		std::shared_ptr<Session_Manager> session_manager;
191		std::shared_ptr<Credentials_Manager> creds;
192		std::shared_ptr<RandomNumberGenerator> rng;
193		std::shared_ptr<const Policy> policy;
194
195		bool received_tls_13_error_alert;
196		bool will_downgrade;
197		};
198
199		std::unique_ptr<Downgrade_Information> m_downgrade_info;
200
201		void preserve_peer_transcript(std::span<const uint8_t> input)
202	0	{
203	0	BOTAN_STATE_CHECK(m_downgrade_info);
204	0	m_downgrade_info->peer_transcript.insert(m_downgrade_info->peer_transcript.end(),
205	0	input.begin(), input.end());
206	0	}
207
208		void preserve_client_hello(std::span<const uint8_t> msg)
209	0	{
210	0	BOTAN_STATE_CHECK(m_downgrade_info);
211	0	m_downgrade_info->client_hello_message.assign(msg.begin(), msg.end());
212	0	}
213
214		friend class Client;
215		friend class Server;
216		void set_io_buffer_size(size_t io_buf_sz)
217	0	{
218	0	BOTAN_STATE_CHECK(m_downgrade_info);
219	0	m_downgrade_info->io_buffer_size = io_buf_sz;
220	0	}
221
222		/**
223		* Implementations use this to signal that the peer indicated a protocol
224		* version downgrade. After calling `request_downgrade()` no further
225		* state changes must be perfomed by the implementation. Particularly, no
226		* further handshake messages must be emitted. Instead, they must yield
227		* control flow back to the underlying Channel implementation to perform
228		* the protocol version downgrade.
229		*/
230		void request_downgrade()
231	0	{
232	0	BOTAN_STATE_CHECK(m_downgrade_info && !m_downgrade_info->will_downgrade);
233	0	m_downgrade_info->will_downgrade = true;
234	0	}
235
236		void request_downgrade_for_resumption(Session_with_Handle session)
237	0	{
238	0	BOTAN_STATE_CHECK(m_downgrade_info &&
239	0	m_downgrade_info->client_hello_message.empty() &&
240	0	m_downgrade_info->peer_transcript.empty() &&
241	0	!m_downgrade_info->tls12_session.has_value());
242	0	BOTAN_ASSERT_NOMSG(session.session.version().is_pre_tls_13());
243	0	m_downgrade_info->tls12_session = std::move(session);
244	0	request_downgrade();
245	0	}
246
247		public:
248		/**
249		* Indicates whether a downgrade to TLS 1.2 or lower is in progress
250		*
251		* @sa Downgrade_Information
252		*/
253	1.48k	bool is_downgrading() const { return m_downgrade_info && m_downgrade_info->will_downgrade; }
254
255		/**
256		* @sa Downgrade_Information
257		*/
258	0	std::unique_ptr<Downgrade_Information> extract_downgrade_info() { return std::exchange(m_downgrade_info, {}); }
259
260	0	bool expects_downgrade() const { return m_downgrade_info != nullptr; }
261		};
262
263		}
264
265		}
266
267		#endif