1 /** 2 * \file md.h 3 * 4 * \brief This file contains the generic message-digest wrapper. 5 * 6 * \author Adriaan de Jong <dejong@fox-it.com> 7 */ 8 /* 9 * Copyright The Mbed TLS Contributors 10 * SPDX-License-Identifier: Apache-2.0 11 * 12 * Licensed under the Apache License, Version 2.0 (the "License"); you may 13 * not use this file except in compliance with the License. 14 * You may obtain a copy of the License at 15 * 16 * http://www.apache.org/licenses/LICENSE-2.0 17 * 18 * Unless required by applicable law or agreed to in writing, software 19 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 20 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 21 * See the License for the specific language governing permissions and 22 * limitations under the License. 23 */ 24 25 #ifndef MBEDTLS_MD_H 26 #define MBEDTLS_MD_H 27 #include "mbedtls/private_access.h" 28 29 #include <stddef.h> 30 31 #include "mbedtls/build_info.h" 32 33 #define MBEDTLS_ERR_MD_FEATURE_UNAVAILABLE -0x5080 /**< The selected feature is not available. */ 34 #define MBEDTLS_ERR_MD_BAD_INPUT_DATA -0x5100 /**< Bad input parameters to function. */ 35 #define MBEDTLS_ERR_MD_ALLOC_FAILED -0x5180 /**< Failed to allocate memory. */ 36 #define MBEDTLS_ERR_MD_FILE_IO_ERROR -0x5200 /**< Opening or reading of file failed. */ 37 38 #ifdef __cplusplus 39 extern "C" { 40 #endif 41 42 /** 43 * \brief Supported message digests. 44 * 45 * \warning MD5 and SHA-1 are considered weak message digests and 46 * their use constitutes a security risk. We recommend considering 47 * stronger message digests instead. 48 * 49 */ 50 typedef enum { 51 MBEDTLS_MD_NONE=0, /**< None. */ 52 MBEDTLS_MD_MD5, /**< The MD5 message digest. */ 53 MBEDTLS_MD_SHA1, /**< The SHA-1 message digest. */ 54 MBEDTLS_MD_SHA224, /**< The SHA-224 message digest. */ 55 MBEDTLS_MD_SHA256, /**< The SHA-256 message digest. */ 56 MBEDTLS_MD_SHA384, /**< The SHA-384 message digest. */ 57 MBEDTLS_MD_SHA512, /**< The SHA-512 message digest. */ 58 MBEDTLS_MD_RIPEMD160, /**< The RIPEMD-160 message digest. */ 59 } mbedtls_md_type_t; 60 61 #if defined(MBEDTLS_SHA512_C) 62 #define MBEDTLS_MD_MAX_SIZE 64 /* longest known is SHA512 */ 63 #else 64 #define MBEDTLS_MD_MAX_SIZE 32 /* longest known is SHA256 or less */ 65 #endif 66 67 #if defined(MBEDTLS_SHA512_C) 68 #define MBEDTLS_MD_MAX_BLOCK_SIZE 128 69 #else 70 #define MBEDTLS_MD_MAX_BLOCK_SIZE 64 71 #endif 72 73 /** 74 * Opaque struct. 75 * 76 * Constructed using either #mbedtls_md_info_from_string or 77 * #mbedtls_md_info_from_type. 78 * 79 * Fields can be accessed with #mbedtls_md_get_size, 80 * #mbedtls_md_get_type and #mbedtls_md_get_name. 81 */ 82 /* Defined internally in library/md_wrap.h. */ 83 typedef struct mbedtls_md_info_t mbedtls_md_info_t; 84 85 /** 86 * The generic message-digest context. 87 */ 88 typedef struct mbedtls_md_context_t 89 { 90 /** Information about the associated message digest. */ 91 const mbedtls_md_info_t *MBEDTLS_PRIVATE(md_info); 92 93 /** The digest-specific context. */ 94 void *MBEDTLS_PRIVATE(md_ctx); 95 96 /** The HMAC part of the context. */ 97 void *MBEDTLS_PRIVATE(hmac_ctx); 98 } mbedtls_md_context_t; 99 100 /** 101 * \brief This function returns the list of digests supported by the 102 * generic digest module. 103 * 104 * \note The list starts with the strongest available hashes. 105 * 106 * \return A statically allocated array of digests. Each element 107 * in the returned list is an integer belonging to the 108 * message-digest enumeration #mbedtls_md_type_t. 109 * The last entry is 0. 110 */ 111 const int *mbedtls_md_list( void ); 112 113 /** 114 * \brief This function returns the message-digest information 115 * associated with the given digest name. 116 * 117 * \param md_name The name of the digest to search for. 118 * 119 * \return The message-digest information associated with \p md_name. 120 * \return NULL if the associated message-digest information is not found. 121 */ 122 const mbedtls_md_info_t *mbedtls_md_info_from_string( const char *md_name ); 123 124 /** 125 * \brief This function returns the message-digest information 126 * associated with the given digest type. 127 * 128 * \param md_type The type of digest to search for. 129 * 130 * \return The message-digest information associated with \p md_type. 131 * \return NULL if the associated message-digest information is not found. 132 */ 133 const mbedtls_md_info_t *mbedtls_md_info_from_type( mbedtls_md_type_t md_type ); 134 135 /** 136 * \brief This function initializes a message-digest context without 137 * binding it to a particular message-digest algorithm. 138 * 139 * This function should always be called first. It prepares the 140 * context for mbedtls_md_setup() for binding it to a 141 * message-digest algorithm. 142 */ 143 void mbedtls_md_init( mbedtls_md_context_t *ctx ); 144 145 /** 146 * \brief This function clears the internal structure of \p ctx and 147 * frees any embedded internal structure, but does not free 148 * \p ctx itself. 149 * 150 * If you have called mbedtls_md_setup() on \p ctx, you must 151 * call mbedtls_md_free() when you are no longer using the 152 * context. 153 * Calling this function if you have previously 154 * called mbedtls_md_init() and nothing else is optional. 155 * You must not call this function if you have not called 156 * mbedtls_md_init(). 157 */ 158 void mbedtls_md_free( mbedtls_md_context_t *ctx ); 159 160 161 /** 162 * \brief This function selects the message digest algorithm to use, 163 * and allocates internal structures. 164 * 165 * It should be called after mbedtls_md_init() or 166 * mbedtls_md_free(). Makes it necessary to call 167 * mbedtls_md_free() later. 168 * 169 * \param ctx The context to set up. 170 * \param md_info The information structure of the message-digest algorithm 171 * to use. 172 * \param hmac Defines if HMAC is used. 0: HMAC is not used (saves some memory), 173 * or non-zero: HMAC is used with this context. 174 * 175 * \return \c 0 on success. 176 * \return #MBEDTLS_ERR_MD_BAD_INPUT_DATA on parameter-verification 177 * failure. 178 * \return #MBEDTLS_ERR_MD_ALLOC_FAILED on memory-allocation failure. 179 */ 180 int mbedtls_md_setup( mbedtls_md_context_t *ctx, const mbedtls_md_info_t *md_info, int hmac ); 181 182 /** 183 * \brief This function clones the state of an message-digest 184 * context. 185 * 186 * \note You must call mbedtls_md_setup() on \c dst before calling 187 * this function. 188 * 189 * \note The two contexts must have the same type, 190 * for example, both are SHA-256. 191 * 192 * \warning This function clones the message-digest state, not the 193 * HMAC state. 194 * 195 * \param dst The destination context. 196 * \param src The context to be cloned. 197 * 198 * \return \c 0 on success. 199 * \return #MBEDTLS_ERR_MD_BAD_INPUT_DATA on parameter-verification failure. 200 */ 201 int mbedtls_md_clone( mbedtls_md_context_t *dst, 202 const mbedtls_md_context_t *src ); 203 204 /** 205 * \brief This function extracts the message-digest size from the 206 * message-digest information structure. 207 * 208 * \param md_info The information structure of the message-digest algorithm 209 * to use. 210 * 211 * \return The size of the message-digest output in Bytes. 212 */ 213 unsigned char mbedtls_md_get_size( const mbedtls_md_info_t *md_info ); 214 215 /** 216 * \brief This function extracts the message-digest type from the 217 * message-digest information structure. 218 * 219 * \param md_info The information structure of the message-digest algorithm 220 * to use. 221 * 222 * \return The type of the message digest. 223 */ 224 mbedtls_md_type_t mbedtls_md_get_type( const mbedtls_md_info_t *md_info ); 225 226 /** 227 * \brief This function extracts the message-digest name from the 228 * message-digest information structure. 229 * 230 * \param md_info The information structure of the message-digest algorithm 231 * to use. 232 * 233 * \return The name of the message digest. 234 */ 235 const char *mbedtls_md_get_name( const mbedtls_md_info_t *md_info ); 236 237 /** 238 * \brief This function starts a message-digest computation. 239 * 240 * You must call this function after setting up the context 241 * with mbedtls_md_setup(), and before passing data with 242 * mbedtls_md_update(). 243 * 244 * \param ctx The generic message-digest context. 245 * 246 * \return \c 0 on success. 247 * \return #MBEDTLS_ERR_MD_BAD_INPUT_DATA on parameter-verification 248 * failure. 249 */ 250 int mbedtls_md_starts( mbedtls_md_context_t *ctx ); 251 252 /** 253 * \brief This function feeds an input buffer into an ongoing 254 * message-digest computation. 255 * 256 * You must call mbedtls_md_starts() before calling this 257 * function. You may call this function multiple times. 258 * Afterwards, call mbedtls_md_finish(). 259 * 260 * \param ctx The generic message-digest context. 261 * \param input The buffer holding the input data. 262 * \param ilen The length of the input data. 263 * 264 * \return \c 0 on success. 265 * \return #MBEDTLS_ERR_MD_BAD_INPUT_DATA on parameter-verification 266 * failure. 267 */ 268 int mbedtls_md_update( mbedtls_md_context_t *ctx, const unsigned char *input, size_t ilen ); 269 270 /** 271 * \brief This function finishes the digest operation, 272 * and writes the result to the output buffer. 273 * 274 * Call this function after a call to mbedtls_md_starts(), 275 * followed by any number of calls to mbedtls_md_update(). 276 * Afterwards, you may either clear the context with 277 * mbedtls_md_free(), or call mbedtls_md_starts() to reuse 278 * the context for another digest operation with the same 279 * algorithm. 280 * 281 * \param ctx The generic message-digest context. 282 * \param output The buffer for the generic message-digest checksum result. 283 * 284 * \return \c 0 on success. 285 * \return #MBEDTLS_ERR_MD_BAD_INPUT_DATA on parameter-verification 286 * failure. 287 */ 288 int mbedtls_md_finish( mbedtls_md_context_t *ctx, unsigned char *output ); 289 290 /** 291 * \brief This function calculates the message-digest of a buffer, 292 * with respect to a configurable message-digest algorithm 293 * in a single call. 294 * 295 * The result is calculated as 296 * Output = message_digest(input buffer). 297 * 298 * \param md_info The information structure of the message-digest algorithm 299 * to use. 300 * \param input The buffer holding the data. 301 * \param ilen The length of the input data. 302 * \param output The generic message-digest checksum result. 303 * 304 * \return \c 0 on success. 305 * \return #MBEDTLS_ERR_MD_BAD_INPUT_DATA on parameter-verification 306 * failure. 307 */ 308 int mbedtls_md( const mbedtls_md_info_t *md_info, const unsigned char *input, size_t ilen, 309 unsigned char *output ); 310 311 #if defined(MBEDTLS_FS_IO) 312 /** 313 * \brief This function calculates the message-digest checksum 314 * result of the contents of the provided file. 315 * 316 * The result is calculated as 317 * Output = message_digest(file contents). 318 * 319 * \param md_info The information structure of the message-digest algorithm 320 * to use. 321 * \param path The input file name. 322 * \param output The generic message-digest checksum result. 323 * 324 * \return \c 0 on success. 325 * \return #MBEDTLS_ERR_MD_FILE_IO_ERROR on an I/O error accessing 326 * the file pointed by \p path. 327 * \return #MBEDTLS_ERR_MD_BAD_INPUT_DATA if \p md_info was NULL. 328 */ 329 int mbedtls_md_file( const mbedtls_md_info_t *md_info, const char *path, 330 unsigned char *output ); 331 #endif /* MBEDTLS_FS_IO */ 332 333 /** 334 * \brief This function sets the HMAC key and prepares to 335 * authenticate a new message. 336 * 337 * Call this function after mbedtls_md_setup(), to use 338 * the MD context for an HMAC calculation, then call 339 * mbedtls_md_hmac_update() to provide the input data, and 340 * mbedtls_md_hmac_finish() to get the HMAC value. 341 * 342 * \param ctx The message digest context containing an embedded HMAC 343 * context. 344 * \param key The HMAC secret key. 345 * \param keylen The length of the HMAC key in Bytes. 346 * 347 * \return \c 0 on success. 348 * \return #MBEDTLS_ERR_MD_BAD_INPUT_DATA on parameter-verification 349 * failure. 350 */ 351 int mbedtls_md_hmac_starts( mbedtls_md_context_t *ctx, const unsigned char *key, 352 size_t keylen ); 353 354 /** 355 * \brief This function feeds an input buffer into an ongoing HMAC 356 * computation. 357 * 358 * Call mbedtls_md_hmac_starts() or mbedtls_md_hmac_reset() 359 * before calling this function. 360 * You may call this function multiple times to pass the 361 * input piecewise. 362 * Afterwards, call mbedtls_md_hmac_finish(). 363 * 364 * \param ctx The message digest context containing an embedded HMAC 365 * context. 366 * \param input The buffer holding the input data. 367 * \param ilen The length of the input data. 368 * 369 * \return \c 0 on success. 370 * \return #MBEDTLS_ERR_MD_BAD_INPUT_DATA on parameter-verification 371 * failure. 372 */ 373 int mbedtls_md_hmac_update( mbedtls_md_context_t *ctx, const unsigned char *input, 374 size_t ilen ); 375 376 /** 377 * \brief This function finishes the HMAC operation, and writes 378 * the result to the output buffer. 379 * 380 * Call this function after mbedtls_md_hmac_starts() and 381 * mbedtls_md_hmac_update() to get the HMAC value. Afterwards 382 * you may either call mbedtls_md_free() to clear the context, 383 * or call mbedtls_md_hmac_reset() to reuse the context with 384 * the same HMAC key. 385 * 386 * \param ctx The message digest context containing an embedded HMAC 387 * context. 388 * \param output The generic HMAC checksum result. 389 * 390 * \return \c 0 on success. 391 * \return #MBEDTLS_ERR_MD_BAD_INPUT_DATA on parameter-verification 392 * failure. 393 */ 394 int mbedtls_md_hmac_finish( mbedtls_md_context_t *ctx, unsigned char *output); 395 396 /** 397 * \brief This function prepares to authenticate a new message with 398 * the same key as the previous HMAC operation. 399 * 400 * You may call this function after mbedtls_md_hmac_finish(). 401 * Afterwards call mbedtls_md_hmac_update() to pass the new 402 * input. 403 * 404 * \param ctx The message digest context containing an embedded HMAC 405 * context. 406 * 407 * \return \c 0 on success. 408 * \return #MBEDTLS_ERR_MD_BAD_INPUT_DATA on parameter-verification 409 * failure. 410 */ 411 int mbedtls_md_hmac_reset( mbedtls_md_context_t *ctx ); 412 413 /** 414 * \brief This function calculates the full generic HMAC 415 * on the input buffer with the provided key. 416 * 417 * The function allocates the context, performs the 418 * calculation, and frees the context. 419 * 420 * The HMAC result is calculated as 421 * output = generic HMAC(hmac key, input buffer). 422 * 423 * \param md_info The information structure of the message-digest algorithm 424 * to use. 425 * \param key The HMAC secret key. 426 * \param keylen The length of the HMAC secret key in Bytes. 427 * \param input The buffer holding the input data. 428 * \param ilen The length of the input data. 429 * \param output The generic HMAC result. 430 * 431 * \return \c 0 on success. 432 * \return #MBEDTLS_ERR_MD_BAD_INPUT_DATA on parameter-verification 433 * failure. 434 */ 435 int mbedtls_md_hmac( const mbedtls_md_info_t *md_info, const unsigned char *key, size_t keylen, 436 const unsigned char *input, size_t ilen, 437 unsigned char *output ); 438 439 /* Internal use */ 440 int mbedtls_md_process( mbedtls_md_context_t *ctx, const unsigned char *data ); 441 442 #ifdef __cplusplus 443 } 444 #endif 445 446 #endif /* MBEDTLS_MD_H */ 447
