/src/botan/build/include/botan/tls_callbacks.h

Source (jump to first uncovered line)
/*
* TLS Callbacks
* (C) 2016 Matthias Gierlings
*     2016 Jack Lloyd
*     2017 Harry Reimann, Rohde & Schwarz Cybersecurity
*
* Botan is released under the Simplified BSD License (see license.txt)
*/

#ifndef BOTAN_TLS_CALLBACKS_H_
#define BOTAN_TLS_CALLBACKS_H_

#include <botan/tls_session.h>
#include <botan/tls_alert.h>
#include <botan/pubkey.h>
#include <functional>

namespace Botan {

class Certificate_Store;
class X509_Certificate;

namespace OCSP {

class Response;

}

namespace TLS {

class Handshake_Message;
class Policy;
class Extensions;
class Certificate_Status_Request;

/**
* Encapsulates the callbacks that a TLS channel will make which are due to
* channel specific operations.
*/
class BOTAN_PUBLIC_API(2,0) Callbacks
   {
   public:
       virtual ~Callbacks() = default;

       /**
       * Mandatory callback: output function
       * The channel will call this with data which needs to be sent to the peer
       * (eg, over a socket or some other form of IPC). The array will be overwritten
       * when the function returns so a copy must be made if the data cannot be
       * sent immediately.
       *
       * @param data the vector of data to send
       *
       * @param size the number of bytes to send
       */
       virtual void tls_emit_data(const uint8_t data[], size_t size) = 0;

       /**
       * Mandatory callback: process application data
       * Called when application data record is received from the peer.
       * Again the array is overwritten immediately after the function returns.
       *
       * @param seq_no the underlying TLS/DTLS record sequence number
       *
       * @param data the vector containing the received record
       *
       * @param size the length of the received record, in bytes
       */
       virtual void tls_record_received(uint64_t seq_no, const uint8_t data[], size_t size) = 0;

       /**
       * Mandatory callback: alert received
       * Called when an alert is received from the peer
       * If fatal, the connection is closing. If not fatal, the connection may
       * still be closing (depending on the error and the peer).
       *
       * @param alert the source of the alert
       */
       virtual void tls_alert(Alert alert) = 0;

       /**
       * Mandatory callback: session established
       * Called when a session is established. Throw an exception to abort
       * the connection.
       *
       * @param session the session descriptor
       *
       * @return return false to prevent the session from being cached,
       * return true to cache the session in the configured session manager
       */
       virtual bool tls_session_established(const Session& session) = 0;

       /**
       * Optional callback: session activated
       * Called when a session is active and can be written to
       */
       virtual void tls_session_activated() {}

       /**
       * Optional callback with default impl: verify cert chain
       *
       * Default implementation performs a standard PKIX validation
       * and initiates network OCSP request for end-entity cert.
       * Override to provide different behavior.
       *
       * Check the certificate chain is valid up to a trusted root, and
       * optionally (if hostname != "") that the hostname given is
       * consistent with the leaf certificate.
       *
       * This function should throw an exception derived from
       * std::exception with an informative what() result if the
       * certificate chain cannot be verified.
       *
       * @param cert_chain specifies a certificate chain leading to a
       *        trusted root CA certificate.
       * @param ocsp_responses the server may have provided some
       * @param trusted_roots the list of trusted certificates
       * @param usage what this cert chain is being used for
       *        Usage_Type::TLS_SERVER_AUTH for server chains,
       *        Usage_Type::TLS_CLIENT_AUTH for client chains,
       *        Usage_Type::UNSPECIFIED for other uses
       * @param hostname when authenticating a server, this is the hostname
       *        the client requested (eg via SNI). When authenticating a client,
       *        this is the server name the client is authenticating *to*.
       *        Empty in other cases or if no hostname was used.
       * @param policy the TLS policy associated with the session being authenticated
       *        using the certificate chain
       */
       virtual void tls_verify_cert_chain(
          const std::vector<X509_Certificate>& cert_chain,
          const std::vector<std::shared_ptr<const OCSP::Response>>& ocsp_responses,
          const std::vector<Certificate_Store*>& trusted_roots,
          Usage_Type usage,
          const std::string& hostname,
          const TLS::Policy& policy);

       /**
       * Called by default `tls_verify_cert_chain` to get the timeout to use for OCSP
       * requests. Return 0 to disable online OCSP checks.
       *
       * This function should not be "const" since the implementation might need
       * to perform some side effecting operation to compute the result.
       */
       virtual std::chrono::milliseconds tls_verify_cert_chain_ocsp_timeout() const
          {
          return std::chrono::milliseconds(0);
          }

      /**
       * Called by the TLS server whenever the client included the
       * status_request extension (see RFC 6066, a.k.a OCSP stapling)
       * in the ClientHello.
       *
       * @return the encoded OCSP response to be sent to the client which
       * indicates the revocation status of the server certificate. Return an
       * empty vector to indicate that no response is available, and thus
       * suppress the Certificate_Status message.
       */
       virtual std::vector<uint8_t> tls_provide_cert_status(const std::vector<X509_Certificate>& chain,
                                                            const Certificate_Status_Request& csr)
          {
          BOTAN_UNUSED(chain);
          BOTAN_UNUSED(csr);
          return std::vector<uint8_t>();
          }

       /**
       * Optional callback with default impl: sign a message
       *
       * Default implementation uses PK_Signer::sign_message().
       * Override to provide a different approach, e.g. using an external device.
       *
       * @param key the private key of the signer
       * @param rng a random number generator
       * @param emsa the encoding method to be applied to the message
       * @param format the signature format
       * @param msg the input data for the signature
       *
       * @return the signature
       */
       virtual std::vector<uint8_t> tls_sign_message(
          const Private_Key& key,
          RandomNumberGenerator& rng,
          const std::string& emsa,
          Signature_Format format,
          const std::vector<uint8_t>& msg);

       /**
       * Optional callback with default impl: verify a message signature
       *
       * Default implementation uses PK_Verifier::verify_message().
       * Override to provide a different approach, e.g. using an external device.
       *
       * @param key the public key of the signer
       * @param emsa the encoding method to be applied to the message
       * @param format the signature format
       * @param msg the input data for the signature
       * @param sig the signature to be checked
       *
       * @return true if the signature is valid, false otherwise
       */
       virtual bool tls_verify_message(
          const Public_Key& key,
          const std::string& emsa,
          Signature_Format format,
          const std::vector<uint8_t>& msg,
          const std::vector<uint8_t>& sig);

       /**
       * Optional callback with default impl: client side DH agreement
       *
       * Default implementation uses PK_Key_Agreement::derive_key().
       * Override to provide a different approach, e.g. using an external device.
       *
       * @param modulus the modulus p of the discrete logarithm group
       * @param generator the generator of the DH subgroup
       * @param peer_public_value the public value of the peer
       * @param policy the TLS policy associated with the session being established
       * @param rng a random number generator
       *
       * @return a pair consisting of the agreed raw secret and our public value
       */
       virtual std::pair<secure_vector<uint8_t>, std::vector<uint8_t>> tls_dh_agree(
          const std::vector<uint8_t>& modulus,
          const std::vector<uint8_t>& generator,
          const std::vector<uint8_t>& peer_public_value,
          const Policy& policy,
          RandomNumberGenerator& rng);

       /**
       * Optional callback with default impl: client side ECDH agreement
       *
       * Default implementation uses PK_Key_Agreement::derive_key().
       * Override to provide a different approach, e.g. using an external device.
       *
       * @param curve_name the name of the elliptic curve
       * @param peer_public_value the public value of the peer
       * @param policy the TLS policy associated with the session being established
       * @param rng a random number generator
       * @param compressed the compression preference for our public value
       *
       * @return a pair consisting of the agreed raw secret and our public value
       */
       virtual std::pair<secure_vector<uint8_t>, std::vector<uint8_t>> tls_ecdh_agree(
          const std::string& curve_name,
          const std::vector<uint8_t>& peer_public_value,
          const Policy& policy,
          RandomNumberGenerator& rng,
          bool compressed);

       /**
       * Optional callback: inspect handshake message
       * Throw an exception to abort the handshake.
       * Default simply ignores the message.
       *
       * @param message the handshake message
       */
       virtual void tls_inspect_handshake_msg(const Handshake_Message& message);

       /**
       * Optional callback for server: choose ALPN protocol
       * ALPN (RFC 7301) works by the client sending a list of application
       * protocols it is willing to negotiate. The server then selects which
       * protocol to use, which is not necessarily even on the list that
       * the client sent.
       *
       * @param client_protos the vector of protocols the client is willing to negotiate
       *
       * @return the protocol selected by the server, which need not be on the
       * list that the client sent; if this is the empty string, the server ignores the
       * client ALPN extension. Default return value is empty string.
       */
       virtual std::string tls_server_choose_app_protocol(const std::vector<std::string>& client_protos);

       /**
       * Optional callback: examine/modify Extensions before sending.
       *
       * Both client and server will call this callback on the Extensions object
       * before serializing it in the client/server hellos. This allows an
       * application to modify which extensions are sent during the
       * handshake.
       *
       * Default implementation does nothing.
       *
       * @param extn the extensions
       * @param which_side will be CLIENT or SERVER which is the current
       * applications role in the exchange.
       */
       virtual void tls_modify_extensions(Extensions& extn, Connection_Side which_side);

       /**
       * Optional callback: examine peer extensions.
       *
       * Both client and server will call this callback with the Extensions
       * object after receiving it from the peer. This allows examining the
       * Extensions, for example to implement a custom extension. It also allows
       * an application to require that a particular extension be implemented;
       * throw an exception from this function to abort the handshake.
       *
       * Default implementation does nothing.
       *
       * @param extn the extensions
       * @param which_side will be CLIENT if these are are the clients extensions (ie we are
       *        the server) or SERVER if these are the server extensions (we are the client).
       */
       virtual void tls_examine_extensions(const Extensions& extn, Connection_Side which_side);

       /**
       * Optional callback: decode TLS group ID
       *
       * TLS uses a 16-bit field to identify ECC and DH groups. This callback
       * handles the decoding. You only need to implement this if you are using
       * a custom ECC or DH group (this is extremely uncommon).
       *
       * Default implementation uses the standard (IETF-defined) mappings.
       */
       virtual std::string tls_decode_group_param(Group_Params group_param);

       /**
       * Optional callback: return peer network identity
       *
       * There is no expected or specified format. The only expectation is this
       * function will return a unique value. For example returning the peer
       * host IP and port.
       *
       * This is used to bind the DTLS cookie to a particular network identity.
       * It is only called if the dtls-cookie-secret PSK is also defined.
       */
       virtual std::string tls_peer_network_identity();

       /**
       * Optional callback: error logging. (not currently called)
       * @param err An error message related to this connection.
       */
       virtual void tls_log_error(const char* err)
          {
          BOTAN_UNUSED(err);
          }

       /**
       * Optional callback: debug logging. (not currently called)
       * @param what Some hopefully informative string
       */
       virtual void tls_log_debug(const char* what)
          {
          BOTAN_UNUSED(what);
          }

       /**
       * Optional callback: debug logging taking a buffer. (not currently called)
       * @param descr What this buffer is
       * @param val the bytes
       * @param val_len length of val
       */
       virtual void tls_log_debug_bin(const char* descr, const uint8_t val[], size_t val_len)
          {
          BOTAN_UNUSED(descr, val, val_len);
          }
   };

}

}

#endif

Coverage Report

Created: 2020-11-21 08:34

Line	Count	Source (jump to first uncovered line)
1		/*
2		* TLS Callbacks
3		* (C) 2016 Matthias Gierlings
4		* 2016 Jack Lloyd
5		* 2017 Harry Reimann, Rohde & Schwarz Cybersecurity
6		*
7		* Botan is released under the Simplified BSD License (see license.txt)
8		*/
9
10		#ifndef BOTAN_TLS_CALLBACKS_H_
11		#define BOTAN_TLS_CALLBACKS_H_
12
13		#include <botan/tls_session.h>
14		#include <botan/tls_alert.h>
15		#include <botan/pubkey.h>
16		#include <functional>
17
18		namespace Botan {
19
20		class Certificate_Store;
21		class X509_Certificate;
22
23		namespace OCSP {
24
25		class Response;
26
27		}
28
29		namespace TLS {
30
31		class Handshake_Message;
32		class Policy;
33		class Extensions;
34		class Certificate_Status_Request;
35
36		/**
37		* Encapsulates the callbacks that a TLS channel will make which are due to
38		* channel specific operations.
39		*/
40		class BOTAN_PUBLIC_API(2,0) Callbacks
41		{
42		public:
43	11.3k	virtual ~Callbacks() = default;
44
45		/**
46		* Mandatory callback: output function
47		* The channel will call this with data which needs to be sent to the peer
48		* (eg, over a socket or some other form of IPC). The array will be overwritten
49		* when the function returns so a copy must be made if the data cannot be
50		* sent immediately.
51		*
52		* @param data the vector of data to send
53		*
54		* @param size the number of bytes to send
55		*/
56		virtual void tls_emit_data(const uint8_t data[], size_t size) = 0;
57
58		/**
59		* Mandatory callback: process application data
60		* Called when application data record is received from the peer.
61		* Again the array is overwritten immediately after the function returns.
62		*
63		* @param seq_no the underlying TLS/DTLS record sequence number
64		*
65		* @param data the vector containing the received record
66		*
67		* @param size the length of the received record, in bytes
68		*/
69		virtual void tls_record_received(uint64_t seq_no, const uint8_t data[], size_t size) = 0;
70
71		/**
72		* Mandatory callback: alert received
73		* Called when an alert is received from the peer
74		* If fatal, the connection is closing. If not fatal, the connection may
75		* still be closing (depending on the error and the peer).
76		*
77		* @param alert the source of the alert
78		*/
79		virtual void tls_alert(Alert alert) = 0;
80
81		/**
82		* Mandatory callback: session established
83		* Called when a session is established. Throw an exception to abort
84		* the connection.
85		*
86		* @param session the session descriptor
87		*
88		* @return return false to prevent the session from being cached,
89		* return true to cache the session in the configured session manager
90		*/
91		virtual bool tls_session_established(const Session& session) = 0;
92
93		/**
94		* Optional callback: session activated
95		* Called when a session is active and can be written to
96		*/
97	532	virtual void tls_session_activated() {}
98
99		/**
100		* Optional callback with default impl: verify cert chain
101		*
102		* Default implementation performs a standard PKIX validation
103		* and initiates network OCSP request for end-entity cert.
104		* Override to provide different behavior.
105		*
106		* Check the certificate chain is valid up to a trusted root, and
107		* optionally (if hostname != "") that the hostname given is
108		* consistent with the leaf certificate.
109		*
110		* This function should throw an exception derived from
111		* std::exception with an informative what() result if the
112		* certificate chain cannot be verified.
113		*
114		* @param cert_chain specifies a certificate chain leading to a
115		* trusted root CA certificate.
116		* @param ocsp_responses the server may have provided some
117		* @param trusted_roots the list of trusted certificates
118		* @param usage what this cert chain is being used for
119		* Usage_Type::TLS_SERVER_AUTH for server chains,
120		* Usage_Type::TLS_CLIENT_AUTH for client chains,
121		* Usage_Type::UNSPECIFIED for other uses
122		* @param hostname when authenticating a server, this is the hostname
123		* the client requested (eg via SNI). When authenticating a client,
124		* this is the server name the client is authenticating to.
125		* Empty in other cases or if no hostname was used.
126		* @param policy the TLS policy associated with the session being authenticated
127		* using the certificate chain
128		*/
129		virtual void tls_verify_cert_chain(
130		const std::vector<X509_Certificate>& cert_chain,
131		const std::vector<std::shared_ptr<const OCSP::Response>>& ocsp_responses,
132		const std::vector<Certificate_Store*>& trusted_roots,
133		Usage_Type usage,
134		const std::string& hostname,
135		const TLS::Policy& policy);
136
137		/**
138		* Called by default `tls_verify_cert_chain` to get the timeout to use for OCSP
139		* requests. Return 0 to disable online OCSP checks.
140		*
141		* This function should not be "const" since the implementation might need
142		* to perform some side effecting operation to compute the result.
143		*/
144		virtual std::chrono::milliseconds tls_verify_cert_chain_ocsp_timeout() const
145	526	{
146	526	return std::chrono::milliseconds(0);
147	526	}
148
149		/**
150		* Called by the TLS server whenever the client included the
151		* status_request extension (see RFC 6066, a.k.a OCSP stapling)
152		* in the ClientHello.
153		*
154		* @return the encoded OCSP response to be sent to the client which
155		* indicates the revocation status of the server certificate. Return an
156		* empty vector to indicate that no response is available, and thus
157		* suppress the Certificate_Status message.
158		*/
159		virtual std::vector<uint8_t> tls_provide_cert_status(const std::vector<X509_Certificate>& chain,
160		const Certificate_Status_Request& csr)
161	5	{
162	5	BOTAN_UNUSED(chain);
163	5	BOTAN_UNUSED(csr);
164	5	return std::vector<uint8_t>();
165	5	}
166
167		/**
168		* Optional callback with default impl: sign a message
169		*
170		* Default implementation uses PK_Signer::sign_message().
171		* Override to provide a different approach, e.g. using an external device.
172		*
173		* @param key the private key of the signer
174		* @param rng a random number generator
175		* @param emsa the encoding method to be applied to the message
176		* @param format the signature format
177		* @param msg the input data for the signature
178		*
179		* @return the signature
180		*/
181		virtual std::vector<uint8_t> tls_sign_message(
182		const Private_Key& key,
183		RandomNumberGenerator& rng,
184		const std::string& emsa,
185		Signature_Format format,
186		const std::vector<uint8_t>& msg);
187
188		/**
189		* Optional callback with default impl: verify a message signature
190		*
191		* Default implementation uses PK_Verifier::verify_message().
192		* Override to provide a different approach, e.g. using an external device.
193		*
194		* @param key the public key of the signer
195		* @param emsa the encoding method to be applied to the message
196		* @param format the signature format
197		* @param msg the input data for the signature
198		* @param sig the signature to be checked
199		*
200		* @return true if the signature is valid, false otherwise
201		*/
202		virtual bool tls_verify_message(
203		const Public_Key& key,
204		const std::string& emsa,
205		Signature_Format format,
206		const std::vector<uint8_t>& msg,
207		const std::vector<uint8_t>& sig);
208
209		/**
210		* Optional callback with default impl: client side DH agreement
211		*
212		* Default implementation uses PK_Key_Agreement::derive_key().
213		* Override to provide a different approach, e.g. using an external device.
214		*
215		* @param modulus the modulus p of the discrete logarithm group
216		* @param generator the generator of the DH subgroup
217		* @param peer_public_value the public value of the peer
218		* @param policy the TLS policy associated with the session being established
219		* @param rng a random number generator
220		*
221		* @return a pair consisting of the agreed raw secret and our public value
222		*/
223		virtual std::pair<secure_vector<uint8_t>, std::vector<uint8_t>> tls_dh_agree(
224		const std::vector<uint8_t>& modulus,
225		const std::vector<uint8_t>& generator,
226		const std::vector<uint8_t>& peer_public_value,
227		const Policy& policy,
228		RandomNumberGenerator& rng);
229
230		/**
231		* Optional callback with default impl: client side ECDH agreement
232		*
233		* Default implementation uses PK_Key_Agreement::derive_key().
234		* Override to provide a different approach, e.g. using an external device.
235		*
236		* @param curve_name the name of the elliptic curve
237		* @param peer_public_value the public value of the peer
238		* @param policy the TLS policy associated with the session being established
239		* @param rng a random number generator
240		* @param compressed the compression preference for our public value
241		*
242		* @return a pair consisting of the agreed raw secret and our public value
243		*/
244		virtual std::pair<secure_vector<uint8_t>, std::vector<uint8_t>> tls_ecdh_agree(
245		const std::string& curve_name,
246		const std::vector<uint8_t>& peer_public_value,
247		const Policy& policy,
248		RandomNumberGenerator& rng,
249		bool compressed);
250
251		/**
252		* Optional callback: inspect handshake message
253		* Throw an exception to abort the handshake.
254		* Default simply ignores the message.
255		*
256		* @param message the handshake message
257		*/
258		virtual void tls_inspect_handshake_msg(const Handshake_Message& message);
259
260		/**
261		* Optional callback for server: choose ALPN protocol
262		* ALPN (RFC 7301) works by the client sending a list of application
263		* protocols it is willing to negotiate. The server then selects which
264		* protocol to use, which is not necessarily even on the list that
265		* the client sent.
266		*
267		* @param client_protos the vector of protocols the client is willing to negotiate
268		*
269		* @return the protocol selected by the server, which need not be on the
270		* list that the client sent; if this is the empty string, the server ignores the
271		* client ALPN extension. Default return value is empty string.
272		*/
273		virtual std::string tls_server_choose_app_protocol(const std::vector<std::string>& client_protos);
274
275		/**
276		* Optional callback: examine/modify Extensions before sending.
277		*
278		* Both client and server will call this callback on the Extensions object
279		* before serializing it in the client/server hellos. This allows an
280		* application to modify which extensions are sent during the
281		* handshake.
282		*
283		* Default implementation does nothing.
284		*
285		* @param extn the extensions
286		* @param which_side will be CLIENT or SERVER which is the current
287		* applications role in the exchange.
288		*/
289		virtual void tls_modify_extensions(Extensions& extn, Connection_Side which_side);
290
291		/**
292		* Optional callback: examine peer extensions.
293		*
294		* Both client and server will call this callback with the Extensions
295		* object after receiving it from the peer. This allows examining the
296		* Extensions, for example to implement a custom extension. It also allows
297		* an application to require that a particular extension be implemented;
298		* throw an exception from this function to abort the handshake.
299		*
300		* Default implementation does nothing.
301		*
302		* @param extn the extensions
303		* @param which_side will be CLIENT if these are are the clients extensions (ie we are
304		* the server) or SERVER if these are the server extensions (we are the client).
305		*/
306		virtual void tls_examine_extensions(const Extensions& extn, Connection_Side which_side);
307
308		/**
309		* Optional callback: decode TLS group ID
310		*
311		* TLS uses a 16-bit field to identify ECC and DH groups. This callback
312		* handles the decoding. You only need to implement this if you are using
313		* a custom ECC or DH group (this is extremely uncommon).
314		*
315		* Default implementation uses the standard (IETF-defined) mappings.
316		*/
317		virtual std::string tls_decode_group_param(Group_Params group_param);
318
319		/**
320		* Optional callback: return peer network identity
321		*
322		* There is no expected or specified format. The only expectation is this
323		* function will return a unique value. For example returning the peer
324		* host IP and port.
325		*
326		* This is used to bind the DTLS cookie to a particular network identity.
327		* It is only called if the dtls-cookie-secret PSK is also defined.
328		*/
329		virtual std::string tls_peer_network_identity();
330
331		/**
332		* Optional callback: error logging. (not currently called)
333		* @param err An error message related to this connection.
334		*/
335		virtual void tls_log_error(const char* err)
336	0	{
337	0	BOTAN_UNUSED(err);
338	0	} Unexecuted instantiation: Botan::TLS::Callbacks::tls_log_error(char const) Unexecuted instantiation: Botan::TLS::Callbacks::tls_log_error(char const)
339
340		/**
341		* Optional callback: debug logging. (not currently called)
342		* @param what Some hopefully informative string
343		*/
344		virtual void tls_log_debug(const char* what)
345	0	{
346	0	BOTAN_UNUSED(what);
347	0	} Unexecuted instantiation: Botan::TLS::Callbacks::tls_log_debug(char const) Unexecuted instantiation: Botan::TLS::Callbacks::tls_log_debug(char const)
348
349		/**
350		* Optional callback: debug logging taking a buffer. (not currently called)
351		* @param descr What this buffer is
352		* @param val the bytes
353		* @param val_len length of val
354		*/
355		virtual void tls_log_debug_bin(const char* descr, const uint8_t val[], size_t val_len)
356	0	{
357	0	BOTAN_UNUSED(descr, val, val_len);
358	0	} Unexecuted instantiation: Botan::TLS::Callbacks::tls_log_debug_bin(char const, unsigned char const, unsigned long) Unexecuted instantiation: Botan::TLS::Callbacks::tls_log_debug_bin(char const, unsigned char const, unsigned long)
359		};
360
361		}
362
363		}
364
365		#endif