1 /* 2 * Copyright 2022-2023 The OpenSSL Project Authors. All Rights Reserved. 3 * 4 * Licensed under the Apache License 2.0 (the "License"). You may not use 5 * this file except in compliance with the License. You can obtain a copy 6 * in the file LICENSE in the source distribution or at 7 * https://www.openssl.org/source/license.html 8 */ 9 10 #ifndef OSSL_INTERNAL_RECORDMETHOD_H 11 # define OSSL_INTERNAL_RECORDMETHOD_H 12 # pragma once 13 14 # include <openssl/ssl.h> 15 16 /* 17 * We use the term "record" here to refer to a packet of data. Records are 18 * typically protected via a cipher and MAC, or an AEAD cipher (although not 19 * always). This usage of the term record is consistent with the TLS concept. 20 * In QUIC the term "record" is not used but it is analogous to the QUIC term 21 * "packet". The interface in this file applies to all protocols that protect 22 * records/packets of data, i.e. (D)TLS and QUIC. The term record is used to 23 * refer to both contexts. 24 */ 25 26 /* 27 * An OSSL_RECORD_METHOD is a protocol specific method which provides the 28 * functions for reading and writing records for that protocol. Which 29 * OSSL_RECORD_METHOD to use for a given protocol is defined by the SSL_METHOD. 30 */ 31 typedef struct ossl_record_method_st OSSL_RECORD_METHOD; 32 33 /* 34 * An OSSL_RECORD_LAYER is just an externally defined opaque pointer created by 35 * the method 36 */ 37 typedef struct ossl_record_layer_st OSSL_RECORD_LAYER; 38 39 40 # define OSSL_RECORD_ROLE_CLIENT 0 41 # define OSSL_RECORD_ROLE_SERVER 1 42 43 # define OSSL_RECORD_DIRECTION_READ 0 44 # define OSSL_RECORD_DIRECTION_WRITE 1 45 46 /* 47 * Protection level. For <= TLSv1.2 only "NONE" and "APPLICATION" are used. 48 */ 49 # define OSSL_RECORD_PROTECTION_LEVEL_NONE 0 50 # define OSSL_RECORD_PROTECTION_LEVEL_EARLY 1 51 # define OSSL_RECORD_PROTECTION_LEVEL_HANDSHAKE 2 52 # define OSSL_RECORD_PROTECTION_LEVEL_APPLICATION 3 53 54 # define OSSL_RECORD_RETURN_SUCCESS 1 55 # define OSSL_RECORD_RETURN_RETRY 0 56 # define OSSL_RECORD_RETURN_NON_FATAL_ERR -1 57 # define OSSL_RECORD_RETURN_FATAL -2 58 # define OSSL_RECORD_RETURN_EOF -3 59 60 /* 61 * Template for creating a record. A record consists of the |type| of data it 62 * will contain (e.g. alert, handshake, application data, etc) along with a 63 * buffer of payload data in |buf| of length |buflen|. 64 */ 65 struct ossl_record_template_st { 66 unsigned char type; 67 unsigned int version; 68 const unsigned char *buf; 69 size_t buflen; 70 }; 71 72 typedef struct ossl_record_template_st OSSL_RECORD_TEMPLATE; 73 74 /* 75 * Rather than a "method" approach, we could make this fetchable - Should we? 76 * There could be some complexity in finding suitable record layer implementations 77 * e.g. we need to find one that matches the negotiated protocol, cipher, 78 * extensions, etc. The selection_cb approach given above doesn't work so well 79 * if unknown third party providers with OSSL_RECORD_METHOD implementations are 80 * loaded. 81 */ 82 83 /* 84 * If this becomes public API then we will need functions to create and 85 * free an OSSL_RECORD_METHOD, as well as functions to get/set the various 86 * function pointers....unless we make it fetchable. 87 */ 88 struct ossl_record_method_st { 89 /* 90 * Create a new OSSL_RECORD_LAYER object for handling the protocol version 91 * set by |vers|. |role| is 0 for client and 1 for server. |direction| 92 * indicates either read or write. |level| is the protection level as 93 * described above. |settings| are mandatory settings that will cause the 94 * new() call to fail if they are not understood (for example to require 95 * Encrypt-Then-Mac support). |options| are optional settings that will not 96 * cause the new() call to fail if they are not understood (for example 97 * whether to use "read ahead" or not). 98 * 99 * The BIO in |transport| is the BIO for the underlying transport layer. 100 * Where the direction is "read", then this BIO will only ever be used for 101 * reading data. Where the direction is "write", then this BIO will only 102 * every be used for writing data. 103 * 104 * An SSL object will always have at least 2 OSSL_RECORD_LAYER objects in 105 * force at any one time (one for reading and one for writing). In some 106 * protocols more than 2 might be used (e.g. in DTLS for retransmitting 107 * messages from an earlier epoch). 108 * 109 * The created OSSL_RECORD_LAYER object is stored in *ret on success (or 110 * NULL otherwise). The return value will be one of 111 * OSSL_RECORD_RETURN_SUCCESS, OSSL_RECORD_RETURN_FATAL or 112 * OSSL_RECORD_RETURN_NON_FATAL. A non-fatal return means that creation of 113 * the record layer has failed because it is unsuitable, but an alternative 114 * record layer can be tried instead. 115 */ 116 117 /* 118 * If we eventually make this fetchable then we will need to use something 119 * other than EVP_CIPHER. Also mactype would not be a NID, but a string. For 120 * now though, this works. 121 */ 122 int (*new_record_layer)(OSSL_LIB_CTX *libctx, 123 const char *propq, int vers, 124 int role, int direction, 125 int level, 126 uint16_t epoch, 127 unsigned char *secret, 128 size_t secretlen, 129 unsigned char *key, 130 size_t keylen, 131 unsigned char *iv, 132 size_t ivlen, 133 unsigned char *mackey, 134 size_t mackeylen, 135 const EVP_CIPHER *ciph, 136 size_t taglen, 137 int mactype, 138 const EVP_MD *md, 139 COMP_METHOD *comp, 140 const EVP_MD *kdfdigest, 141 BIO *prev, 142 BIO *transport, 143 BIO *next, 144 BIO_ADDR *local, 145 BIO_ADDR *peer, 146 const OSSL_PARAM *settings, 147 const OSSL_PARAM *options, 148 const OSSL_DISPATCH *fns, 149 void *cbarg, 150 void *rlarg, 151 OSSL_RECORD_LAYER **ret); 152 int (*free)(OSSL_RECORD_LAYER *rl); 153 154 /* Returns 1 if we have unprocessed data buffered or 0 otherwise */ 155 int (*unprocessed_read_pending)(OSSL_RECORD_LAYER *rl); 156 157 /* 158 * Returns 1 if we have processed data buffered that can be read or 0 otherwise 159 * - not necessarily app data 160 */ 161 int (*processed_read_pending)(OSSL_RECORD_LAYER *rl); 162 163 /* 164 * The amount of processed app data that is internally buffered and 165 * available to read 166 */ 167 size_t (*app_data_pending)(OSSL_RECORD_LAYER *rl); 168 169 /* 170 * Find out the maximum number of records that the record layer is prepared 171 * to process in a single call to write_records. It is the caller's 172 * responsibility to ensure that no call to write_records exceeds this 173 * number of records. |type| is the type of the records that the caller 174 * wants to write, and |len| is the total amount of data that it wants 175 * to send. |maxfrag| is the maximum allowed fragment size based on user 176 * configuration, or TLS parameter negotiation. |*preffrag| contains on 177 * entry the default fragment size that will actually be used based on user 178 * configuration. This will always be less than or equal to |maxfrag|. On 179 * exit the record layer may update this to an alternative fragment size to 180 * be used. This must always be less than or equal to |maxfrag|. 181 */ 182 size_t (*get_max_records)(OSSL_RECORD_LAYER *rl, uint8_t type, size_t len, 183 size_t maxfrag, size_t *preffrag); 184 185 /* 186 * Write |numtempl| records from the array of record templates pointed to 187 * by |templates|. Each record should be no longer than the value returned 188 * by get_max_record_len(), and there should be no more records than the 189 * value returned by get_max_records(). 190 * Where possible the caller will attempt to ensure that all records are the 191 * same length, except the last record. This may not always be possible so 192 * the record method implementation should not rely on this being the case. 193 * In the event of a retry the caller should call retry_write_records() 194 * to try again. No more calls to write_records() should be attempted until 195 * retry_write_records() returns success. 196 * Buffers allocated for the record templates can be freed immediately after 197 * write_records() returns - even in the case a retry. 198 * The record templates represent the plaintext payload. The encrypted 199 * output is written to the |transport| BIO. 200 * Returns: 201 * 1 on success 202 * 0 on retry 203 * -1 on failure 204 */ 205 int (*write_records)(OSSL_RECORD_LAYER *rl, OSSL_RECORD_TEMPLATE *templates, 206 size_t numtempl); 207 208 /* 209 * Retry a previous call to write_records. The caller should continue to 210 * call this until the function returns with success or failure. After 211 * each retry more of the data may have been incrementally sent. 212 * Returns: 213 * 1 on success 214 * 0 on retry 215 * -1 on failure 216 */ 217 int (*retry_write_records)(OSSL_RECORD_LAYER *rl); 218 219 /* 220 * Read a record and return the record layer version and record type in 221 * the |rversion| and |type| parameters. |*data| is set to point to a 222 * record layer buffer containing the record payload data and |*datalen| 223 * is filled in with the length of that data. The |epoch| and |seq_num| 224 * values are only used if DTLS has been negotiated. In that case they are 225 * filled in with the epoch and sequence number from the record. 226 * An opaque record layer handle for the record is returned in |*rechandle| 227 * which is used in a subsequent call to |release_record|. The buffer must 228 * remain available until all the bytes from record are released via one or 229 * more release_record calls. 230 * 231 * Internally the OSSL_RECORD_METHOD implementation may read/process 232 * multiple records in one go and buffer them. 233 */ 234 int (*read_record)(OSSL_RECORD_LAYER *rl, void **rechandle, int *rversion, 235 uint8_t *type, const unsigned char **data, size_t *datalen, 236 uint16_t *epoch, unsigned char *seq_num); 237 /* 238 * Release length bytes from a buffer associated with a record previously 239 * read with read_record. Once all the bytes from a record are released, the 240 * whole record and its associated buffer is released. Records are 241 * guaranteed to be released in the order that they are read. 242 */ 243 int (*release_record)(OSSL_RECORD_LAYER *rl, void *rechandle, size_t length); 244 245 /* 246 * In the event that a fatal error is returned from the functions above then 247 * get_alert_code() can be called to obtain a more details identifier for 248 * the error. In (D)TLS this is the alert description code. 249 */ 250 int (*get_alert_code)(OSSL_RECORD_LAYER *rl); 251 252 /* 253 * Update the transport BIO from the one originally set in the 254 * new_record_layer call 255 */ 256 int (*set1_bio)(OSSL_RECORD_LAYER *rl, BIO *bio); 257 258 /* Called when protocol negotiation selects a protocol version to use */ 259 int (*set_protocol_version)(OSSL_RECORD_LAYER *rl, int version); 260 261 /* 262 * Whether we are allowed to receive unencrypted alerts, even if we might 263 * otherwise expect encrypted records. Ignored by protocol versions where 264 * this isn't relevant 265 */ 266 void (*set_plain_alerts)(OSSL_RECORD_LAYER *rl, int allow); 267 268 /* 269 * Called immediately after creation of the record layer if we are in a 270 * first handshake. Also called at the end of the first handshake 271 */ 272 void (*set_first_handshake)(OSSL_RECORD_LAYER *rl, int first); 273 274 /* 275 * Set the maximum number of pipelines that the record layer should process. 276 * The default is 1. 277 */ 278 void (*set_max_pipelines)(OSSL_RECORD_LAYER *rl, size_t max_pipelines); 279 280 /* 281 * Called to tell the record layer whether we are currently "in init" or 282 * not. Default at creation of the record layer is "yes". 283 */ 284 void (*set_in_init)(OSSL_RECORD_LAYER *rl, int in_init); 285 286 /* 287 * Get a short or long human readable description of the record layer state 288 */ 289 void (*get_state)(OSSL_RECORD_LAYER *rl, const char **shortstr, 290 const char **longstr); 291 292 /* 293 * Set new options or modify ones that were originally specified in the 294 * new_record_layer call. 295 */ 296 int (*set_options)(OSSL_RECORD_LAYER *rl, const OSSL_PARAM *options); 297 298 const COMP_METHOD *(*get_compression)(OSSL_RECORD_LAYER *rl); 299 300 /* 301 * Set the maximum fragment length to be used for the record layer. This 302 * will override any previous value supplied for the "max_frag_len" 303 * setting during construction of the record layer. 304 */ 305 void (*set_max_frag_len)(OSSL_RECORD_LAYER *rl, size_t max_frag_len); 306 307 /* 308 * The maximum expansion in bytes that the record layer might add while 309 * writing a record 310 */ 311 size_t (*get_max_record_overhead)(OSSL_RECORD_LAYER *rl); 312 313 /* 314 * Increment the record sequence number 315 */ 316 int (*increment_sequence_ctr)(OSSL_RECORD_LAYER *rl); 317 318 /* 319 * Allocate read or write buffers. Does nothing if already allocated. 320 * Assumes default buffer length and 1 pipeline. 321 */ 322 int (*alloc_buffers)(OSSL_RECORD_LAYER *rl); 323 324 /* 325 * Free read or write buffers. Fails if there is pending read or write 326 * data. Buffers are automatically reallocated on next read/write. 327 */ 328 int (*free_buffers)(OSSL_RECORD_LAYER *rl); 329 }; 330 331 332 /* Standard built-in record methods */ 333 extern const OSSL_RECORD_METHOD ossl_tls_record_method; 334 # ifndef OPENSSL_NO_KTLS 335 extern const OSSL_RECORD_METHOD ossl_ktls_record_method; 336 # endif 337 extern const OSSL_RECORD_METHOD ossl_dtls_record_method; 338 339 #endif /* !defined(OSSL_INTERNAL_RECORDMETHOD_H) */ 340
