1/* 2 * Copyright 2016-2023 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/* 11 * HMAC low level APIs are deprecated for public use, but still ok for internal 12 * use. 13 */ 14#include "internal/deprecated.h" 15 16#include <stdlib.h> 17#include <stdarg.h> 18#include <string.h> 19#include <openssl/hmac.h> 20#include <openssl/evp.h> 21#include <openssl/kdf.h> 22#include <openssl/core_names.h> 23#include <openssl/proverr.h> 24#include "internal/cryptlib.h" 25#include "internal/numbers.h" 26#include "internal/packet.h" 27#include "crypto/evp.h" 28#include "prov/provider_ctx.h" 29#include "prov/providercommon.h" 30#include "prov/implementations.h" 31#include "prov/provider_util.h" 32#include "e_os.h" 33 34#define HKDF_MAXBUF 2048 35#define HKDF_MAXINFO (32*1024) 36 37static OSSL_FUNC_kdf_newctx_fn kdf_hkdf_new; 38static OSSL_FUNC_kdf_freectx_fn kdf_hkdf_free; 39static OSSL_FUNC_kdf_reset_fn kdf_hkdf_reset; 40static OSSL_FUNC_kdf_derive_fn kdf_hkdf_derive; 41static OSSL_FUNC_kdf_settable_ctx_params_fn kdf_hkdf_settable_ctx_params; 42static OSSL_FUNC_kdf_set_ctx_params_fn kdf_hkdf_set_ctx_params; 43static OSSL_FUNC_kdf_gettable_ctx_params_fn kdf_hkdf_gettable_ctx_params; 44static OSSL_FUNC_kdf_get_ctx_params_fn kdf_hkdf_get_ctx_params; 45static OSSL_FUNC_kdf_derive_fn kdf_tls1_3_derive; 46static OSSL_FUNC_kdf_settable_ctx_params_fn kdf_tls1_3_settable_ctx_params; 47static OSSL_FUNC_kdf_set_ctx_params_fn kdf_tls1_3_set_ctx_params; 48 49static int HKDF(OSSL_LIB_CTX *libctx, const EVP_MD *evp_md, 50 const unsigned char *salt, size_t salt_len, 51 const unsigned char *key, size_t key_len, 52 const unsigned char *info, size_t info_len, 53 unsigned char *okm, size_t okm_len); 54static int HKDF_Extract(OSSL_LIB_CTX *libctx, const EVP_MD *evp_md, 55 const unsigned char *salt, size_t salt_len, 56 const unsigned char *ikm, size_t ikm_len, 57 unsigned char *prk, size_t prk_len); 58static int HKDF_Expand(const EVP_MD *evp_md, 59 const unsigned char *prk, size_t prk_len, 60 const unsigned char *info, size_t info_len, 61 unsigned char *okm, size_t okm_len); 62 63/* Settable context parameters that are common across HKDF and the TLS KDF */ 64#define HKDF_COMMON_SETTABLES \ 65 OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_MODE, NULL, 0), \ 66 OSSL_PARAM_int(OSSL_KDF_PARAM_MODE, NULL), \ 67 OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_PROPERTIES, NULL, 0), \ 68 OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_DIGEST, NULL, 0), \ 69 OSSL_PARAM_octet_string(OSSL_KDF_PARAM_KEY, NULL, 0), \ 70 OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SALT, NULL, 0) 71 72typedef struct { 73 void *provctx; 74 int mode; 75 PROV_DIGEST digest; 76 unsigned char *salt; 77 size_t salt_len; 78 unsigned char *key; 79 size_t key_len; 80 unsigned char *prefix; 81 size_t prefix_len; 82 unsigned char *label; 83 size_t label_len; 84 unsigned char *data; 85 size_t data_len; 86 unsigned char *info; 87 size_t info_len; 88} KDF_HKDF; 89 90static void *kdf_hkdf_new(void *provctx) 91{ 92 KDF_HKDF *ctx; 93 94 if (!ossl_prov_is_running()) 95 return NULL; 96 97 if ((ctx = OPENSSL_zalloc(sizeof(*ctx))) == NULL) 98 ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE); 99 else 100 ctx->provctx = provctx; 101 return ctx; 102} 103 104static void kdf_hkdf_free(void *vctx) 105{ 106 KDF_HKDF *ctx = (KDF_HKDF *)vctx; 107 108 if (ctx != NULL) { 109 kdf_hkdf_reset(ctx); 110 OPENSSL_free(ctx); 111 } 112} 113 114static void kdf_hkdf_reset(void *vctx) 115{ 116 KDF_HKDF *ctx = (KDF_HKDF *)vctx; 117 void *provctx = ctx->provctx; 118 119 ossl_prov_digest_reset(&ctx->digest); 120 OPENSSL_free(ctx->salt); 121 OPENSSL_free(ctx->prefix); 122 OPENSSL_free(ctx->label); 123 OPENSSL_clear_free(ctx->data, ctx->data_len); 124 OPENSSL_clear_free(ctx->key, ctx->key_len); 125 OPENSSL_clear_free(ctx->info, ctx->info_len); 126 memset(ctx, 0, sizeof(*ctx)); 127 ctx->provctx = provctx; 128} 129 130static size_t kdf_hkdf_size(KDF_HKDF *ctx) 131{ 132 int sz; 133 const EVP_MD *md = ossl_prov_digest_md(&ctx->digest); 134 135 if (ctx->mode != EVP_KDF_HKDF_MODE_EXTRACT_ONLY) 136 return SIZE_MAX; 137 138 if (md == NULL) { 139 ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MESSAGE_DIGEST); 140 return 0; 141 } 142 sz = EVP_MD_get_size(md); 143 if (sz < 0) 144 return 0; 145 146 return sz; 147} 148 149static int kdf_hkdf_derive(void *vctx, unsigned char *key, size_t keylen, 150 const OSSL_PARAM params[]) 151{ 152 KDF_HKDF *ctx = (KDF_HKDF *)vctx; 153 OSSL_LIB_CTX *libctx = PROV_LIBCTX_OF(ctx->provctx); 154 const EVP_MD *md; 155 156 if (!ossl_prov_is_running() || !kdf_hkdf_set_ctx_params(ctx, params)) 157 return 0; 158 159 md = ossl_prov_digest_md(&ctx->digest); 160 if (md == NULL) { 161 ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MESSAGE_DIGEST); 162 return 0; 163 } 164 if (ctx->key == NULL) { 165 ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_KEY); 166 return 0; 167 } 168 if (keylen == 0) { 169 ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_KEY_LENGTH); 170 return 0; 171 } 172 173 switch (ctx->mode) { 174 case EVP_KDF_HKDF_MODE_EXTRACT_AND_EXPAND: 175 default: 176 return HKDF(libctx, md, ctx->salt, ctx->salt_len, 177 ctx->key, ctx->key_len, ctx->info, ctx->info_len, key, keylen); 178 179 case EVP_KDF_HKDF_MODE_EXTRACT_ONLY: 180 return HKDF_Extract(libctx, md, ctx->salt, ctx->salt_len, 181 ctx->key, ctx->key_len, key, keylen); 182 183 case EVP_KDF_HKDF_MODE_EXPAND_ONLY: 184 return HKDF_Expand(md, ctx->key, ctx->key_len, ctx->info, 185 ctx->info_len, key, keylen); 186 } 187} 188 189static int hkdf_common_set_ctx_params(KDF_HKDF *ctx, const OSSL_PARAM params[]) 190{ 191 OSSL_LIB_CTX *libctx = PROV_LIBCTX_OF(ctx->provctx); 192 const OSSL_PARAM *p; 193 int n; 194 195 if (params == NULL) 196 return 1; 197 198 if (!ossl_prov_digest_load_from_params(&ctx->digest, params, libctx)) 199 return 0; 200 201 if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_MODE)) != NULL) { 202 if (p->data_type == OSSL_PARAM_UTF8_STRING) { 203 if (OPENSSL_strcasecmp(p->data, "EXTRACT_AND_EXPAND") == 0) { 204 ctx->mode = EVP_KDF_HKDF_MODE_EXTRACT_AND_EXPAND; 205 } else if (OPENSSL_strcasecmp(p->data, "EXTRACT_ONLY") == 0) { 206 ctx->mode = EVP_KDF_HKDF_MODE_EXTRACT_ONLY; 207 } else if (OPENSSL_strcasecmp(p->data, "EXPAND_ONLY") == 0) { 208 ctx->mode = EVP_KDF_HKDF_MODE_EXPAND_ONLY; 209 } else { 210 ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_MODE); 211 return 0; 212 } 213 } else if (OSSL_PARAM_get_int(p, &n)) { 214 if (n != EVP_KDF_HKDF_MODE_EXTRACT_AND_EXPAND 215 && n != EVP_KDF_HKDF_MODE_EXTRACT_ONLY 216 && n != EVP_KDF_HKDF_MODE_EXPAND_ONLY) { 217 ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_MODE); 218 return 0; 219 } 220 ctx->mode = n; 221 } else { 222 ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_MODE); 223 return 0; 224 } 225 } 226 227 if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_KEY)) != NULL) { 228 OPENSSL_clear_free(ctx->key, ctx->key_len); 229 ctx->key = NULL; 230 if (!OSSL_PARAM_get_octet_string(p, (void **)&ctx->key, 0, 231 &ctx->key_len)) 232 return 0; 233 } 234 235 if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SALT)) != NULL) { 236 if (p->data_size != 0 && p->data != NULL) { 237 OPENSSL_free(ctx->salt); 238 ctx->salt = NULL; 239 if (!OSSL_PARAM_get_octet_string(p, (void **)&ctx->salt, 0, 240 &ctx->salt_len)) 241 return 0; 242 } 243 } 244 245 return 1; 246} 247 248/* 249 * Use WPACKET to concat one or more OSSL_KDF_PARAM_INFO fields into a fixed 250 * out buffer of size *outlen. 251 * If out is NULL then outlen is used to return the required buffer size. 252 */ 253static int setinfo_fromparams(const OSSL_PARAM *p, unsigned char *out, size_t *outlen) 254{ 255 int ret = 0; 256 WPACKET pkt; 257 258 if (out == NULL) { 259 if (!WPACKET_init_null(&pkt, 0)) 260 return 0; 261 } else { 262 if (!WPACKET_init_static_len(&pkt, out, *outlen, 0)) 263 return 0; 264 } 265 266 for (; p != NULL; p = OSSL_PARAM_locate_const(p + 1, OSSL_KDF_PARAM_INFO)) { 267 if (p->data_type != OSSL_PARAM_OCTET_STRING) 268 goto err; 269 if (p->data != NULL 270 && p->data_size != 0 271 && !WPACKET_memcpy(&pkt, p->data, p->data_size)) 272 goto err; 273 } 274 if (!WPACKET_get_total_written(&pkt, outlen) 275 || !WPACKET_finish(&pkt)) 276 goto err; 277 ret = 1; 278err: 279 WPACKET_cleanup(&pkt); 280 return ret; 281} 282 283static int kdf_hkdf_set_ctx_params(void *vctx, const OSSL_PARAM params[]) 284{ 285 const OSSL_PARAM *p; 286 KDF_HKDF *ctx = vctx; 287 288 if (params == NULL) 289 return 1; 290 291 if (!hkdf_common_set_ctx_params(ctx, params)) 292 return 0; 293 294 /* The info fields concatenate, so process them all */ 295 if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_INFO)) != NULL) { 296 size_t sz = 0; 297 298 /* calculate the total size */ 299 if (!setinfo_fromparams(p, NULL, &sz)) 300 return 0; 301 if (sz > HKDF_MAXINFO) 302 return 0; 303 304 OPENSSL_clear_free(ctx->info, ctx->info_len); 305 ctx->info = NULL; 306 if (sz == 0) 307 return 1; 308 /* Alloc the buffer */ 309 ctx->info = OPENSSL_malloc(sz); 310 if (ctx->info == NULL) 311 return 0; 312 ctx->info_len = sz; 313 /* Concat one or more OSSL_KDF_PARAM_INFO fields */ 314 if (!setinfo_fromparams(p, ctx->info, &sz)) 315 return 0; 316 } 317 return 1; 318} 319 320static const OSSL_PARAM *kdf_hkdf_settable_ctx_params(ossl_unused void *ctx, 321 ossl_unused void *provctx) 322{ 323 static const OSSL_PARAM known_settable_ctx_params[] = { 324 HKDF_COMMON_SETTABLES, 325 OSSL_PARAM_octet_string(OSSL_KDF_PARAM_INFO, NULL, 0), 326 OSSL_PARAM_END 327 }; 328 return known_settable_ctx_params; 329} 330 331static int kdf_hkdf_get_ctx_params(void *vctx, OSSL_PARAM params[]) 332{ 333 KDF_HKDF *ctx = (KDF_HKDF *)vctx; 334 OSSL_PARAM *p; 335 336 if ((p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_SIZE)) != NULL) { 337 size_t sz = kdf_hkdf_size(ctx); 338 339 if (sz == 0) 340 return 0; 341 return OSSL_PARAM_set_size_t(p, sz); 342 } 343 return -2; 344} 345 346static const OSSL_PARAM *kdf_hkdf_gettable_ctx_params(ossl_unused void *ctx, 347 ossl_unused void *provctx) 348{ 349 static const OSSL_PARAM known_gettable_ctx_params[] = { 350 OSSL_PARAM_size_t(OSSL_KDF_PARAM_SIZE, NULL), 351 OSSL_PARAM_END 352 }; 353 return known_gettable_ctx_params; 354} 355 356const OSSL_DISPATCH ossl_kdf_hkdf_functions[] = { 357 { OSSL_FUNC_KDF_NEWCTX, (void(*)(void))kdf_hkdf_new }, 358 { OSSL_FUNC_KDF_FREECTX, (void(*)(void))kdf_hkdf_free }, 359 { OSSL_FUNC_KDF_RESET, (void(*)(void))kdf_hkdf_reset }, 360 { OSSL_FUNC_KDF_DERIVE, (void(*)(void))kdf_hkdf_derive }, 361 { OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS, 362 (void(*)(void))kdf_hkdf_settable_ctx_params }, 363 { OSSL_FUNC_KDF_SET_CTX_PARAMS, (void(*)(void))kdf_hkdf_set_ctx_params }, 364 { OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS, 365 (void(*)(void))kdf_hkdf_gettable_ctx_params }, 366 { OSSL_FUNC_KDF_GET_CTX_PARAMS, (void(*)(void))kdf_hkdf_get_ctx_params }, 367 { 0, NULL } 368}; 369 370/* 371 * Refer to "HMAC-based Extract-and-Expand Key Derivation Function (HKDF)" 372 * Section 2 (https://tools.ietf.org/html/rfc5869#section-2) and 373 * "Cryptographic Extraction and Key Derivation: The HKDF Scheme" 374 * Section 4.2 (https://eprint.iacr.org/2010/264.pdf). 375 * 376 * From the paper: 377 * The scheme HKDF is specified as: 378 * HKDF(XTS, SKM, CTXinfo, L) = K(1) | K(2) | ... | K(t) 379 * 380 * where: 381 * SKM is source key material 382 * XTS is extractor salt (which may be null or constant) 383 * CTXinfo is context information (may be null) 384 * L is the number of key bits to be produced by KDF 385 * k is the output length in bits of the hash function used with HMAC 386 * t = ceil(L/k) 387 * the value K(t) is truncated to its first d = L mod k bits. 388 * 389 * From RFC 5869: 390 * 2.2. Step 1: Extract 391 * HKDF-Extract(salt, IKM) -> PRK 392 * 2.3. Step 2: Expand 393 * HKDF-Expand(PRK, info, L) -> OKM 394 */ 395static int HKDF(OSSL_LIB_CTX *libctx, const EVP_MD *evp_md, 396 const unsigned char *salt, size_t salt_len, 397 const unsigned char *ikm, size_t ikm_len, 398 const unsigned char *info, size_t info_len, 399 unsigned char *okm, size_t okm_len) 400{ 401 unsigned char prk[EVP_MAX_MD_SIZE]; 402 int ret, sz; 403 size_t prk_len; 404 405 sz = EVP_MD_get_size(evp_md); 406 if (sz < 0) 407 return 0; 408 prk_len = (size_t)sz; 409 410 /* Step 1: HKDF-Extract(salt, IKM) -> PRK */ 411 if (!HKDF_Extract(libctx, evp_md, 412 salt, salt_len, ikm, ikm_len, prk, prk_len)) 413 return 0; 414 415 /* Step 2: HKDF-Expand(PRK, info, L) -> OKM */ 416 ret = HKDF_Expand(evp_md, prk, prk_len, info, info_len, okm, okm_len); 417 OPENSSL_cleanse(prk, sizeof(prk)); 418 419 return ret; 420} 421 422/* 423 * Refer to "HMAC-based Extract-and-Expand Key Derivation Function (HKDF)" 424 * Section 2.2 (https://tools.ietf.org/html/rfc5869#section-2.2). 425 * 426 * 2.2. Step 1: Extract 427 * 428 * HKDF-Extract(salt, IKM) -> PRK 429 * 430 * Options: 431 * Hash a hash function; HashLen denotes the length of the 432 * hash function output in octets 433 * 434 * Inputs: 435 * salt optional salt value (a non-secret random value); 436 * if not provided, it is set to a string of HashLen zeros. 437 * IKM input keying material 438 * 439 * Output: 440 * PRK a pseudorandom key (of HashLen octets) 441 * 442 * The output PRK is calculated as follows: 443 * 444 * PRK = HMAC-Hash(salt, IKM) 445 */ 446static int HKDF_Extract(OSSL_LIB_CTX *libctx, const EVP_MD *evp_md, 447 const unsigned char *salt, size_t salt_len, 448 const unsigned char *ikm, size_t ikm_len, 449 unsigned char *prk, size_t prk_len) 450{ 451 int sz = EVP_MD_get_size(evp_md); 452 453 if (sz < 0) 454 return 0; 455 if (prk_len != (size_t)sz) { 456 ERR_raise(ERR_LIB_PROV, PROV_R_WRONG_OUTPUT_BUFFER_SIZE); 457 return 0; 458 } 459 /* calc: PRK = HMAC-Hash(salt, IKM) */ 460 return 461 EVP_Q_mac(libctx, "HMAC", NULL, EVP_MD_get0_name(evp_md), NULL, salt, 462 salt_len, ikm, ikm_len, prk, EVP_MD_get_size(evp_md), NULL) 463 != NULL; 464} 465 466/* 467 * Refer to "HMAC-based Extract-and-Expand Key Derivation Function (HKDF)" 468 * Section 2.3 (https://tools.ietf.org/html/rfc5869#section-2.3). 469 * 470 * 2.3. Step 2: Expand 471 * 472 * HKDF-Expand(PRK, info, L) -> OKM 473 * 474 * Options: 475 * Hash a hash function; HashLen denotes the length of the 476 * hash function output in octets 477 * 478 * Inputs: 479 * PRK a pseudorandom key of at least HashLen octets 480 * (usually, the output from the extract step) 481 * info optional context and application specific information 482 * (can be a zero-length string) 483 * L length of output keying material in octets 484 * (<= 255*HashLen) 485 * 486 * Output: 487 * OKM output keying material (of L octets) 488 * 489 * The output OKM is calculated as follows: 490 * 491 * N = ceil(L/HashLen) 492 * T = T(1) | T(2) | T(3) | ... | T(N) 493 * OKM = first L octets of T 494 * 495 * where: 496 * T(0) = empty string (zero length) 497 * T(1) = HMAC-Hash(PRK, T(0) | info | 0x01) 498 * T(2) = HMAC-Hash(PRK, T(1) | info | 0x02) 499 * T(3) = HMAC-Hash(PRK, T(2) | info | 0x03) 500 * ... 501 * 502 * (where the constant concatenated to the end of each T(n) is a 503 * single octet.) 504 */ 505static int HKDF_Expand(const EVP_MD *evp_md, 506 const unsigned char *prk, size_t prk_len, 507 const unsigned char *info, size_t info_len, 508 unsigned char *okm, size_t okm_len) 509{ 510 HMAC_CTX *hmac; 511 int ret = 0, sz; 512 unsigned int i; 513 unsigned char prev[EVP_MAX_MD_SIZE]; 514 size_t done_len = 0, dig_len, n; 515 516 sz = EVP_MD_get_size(evp_md); 517 if (sz <= 0) 518 return 0; 519 dig_len = (size_t)sz; 520 521 /* calc: N = ceil(L/HashLen) */ 522 n = okm_len / dig_len; 523 if (okm_len % dig_len) 524 n++; 525 526 if (n > 255 || okm == NULL) 527 return 0; 528 529 if ((hmac = HMAC_CTX_new()) == NULL) 530 return 0; 531 532 if (!HMAC_Init_ex(hmac, prk, prk_len, evp_md, NULL)) 533 goto err; 534 535 for (i = 1; i <= n; i++) { 536 size_t copy_len; 537 const unsigned char ctr = i; 538 539 /* calc: T(i) = HMAC-Hash(PRK, T(i - 1) | info | i) */ 540 if (i > 1) { 541 if (!HMAC_Init_ex(hmac, NULL, 0, NULL, NULL)) 542 goto err; 543 544 if (!HMAC_Update(hmac, prev, dig_len)) 545 goto err; 546 } 547 548 if (!HMAC_Update(hmac, info, info_len)) 549 goto err; 550 551 if (!HMAC_Update(hmac, &ctr, 1)) 552 goto err; 553 554 if (!HMAC_Final(hmac, prev, NULL)) 555 goto err; 556 557 copy_len = (dig_len > okm_len - done_len) ? 558 okm_len - done_len : 559 dig_len; 560 561 memcpy(okm + done_len, prev, copy_len); 562 563 done_len += copy_len; 564 } 565 ret = 1; 566 567 err: 568 OPENSSL_cleanse(prev, sizeof(prev)); 569 HMAC_CTX_free(hmac); 570 return ret; 571} 572 573/* 574 * TLS uses slight variations of the above and for FIPS validation purposes, 575 * they need to be present here. 576 * Refer to RFC 8446 section 7 for specific details. 577 */ 578 579/* 580 * Given a |secret|; a |label| of length |labellen|; and |data| of length 581 * |datalen| (e.g. typically a hash of the handshake messages), derive a new 582 * secret |outlen| bytes long and store it in the location pointed to be |out|. 583 * The |data| value may be zero length. Returns 1 on success and 0 on failure. 584 */ 585static int prov_tls13_hkdf_expand(const EVP_MD *md, 586 const unsigned char *key, size_t keylen, 587 const unsigned char *prefix, size_t prefixlen, 588 const unsigned char *label, size_t labellen, 589 const unsigned char *data, size_t datalen, 590 unsigned char *out, size_t outlen) 591{ 592 size_t hkdflabellen; 593 unsigned char hkdflabel[HKDF_MAXBUF]; 594 WPACKET pkt; 595 596 /* 597 * 2 bytes for length of derived secret + 1 byte for length of combined 598 * prefix and label + bytes for the label itself + 1 byte length of hash 599 * + bytes for the hash itself. We've got the maximum the KDF can handle 600 * which should always be sufficient. 601 */ 602 if (!WPACKET_init_static_len(&pkt, hkdflabel, sizeof(hkdflabel), 0) 603 || !WPACKET_put_bytes_u16(&pkt, outlen) 604 || !WPACKET_start_sub_packet_u8(&pkt) 605 || !WPACKET_memcpy(&pkt, prefix, prefixlen) 606 || !WPACKET_memcpy(&pkt, label, labellen) 607 || !WPACKET_close(&pkt) 608 || !WPACKET_sub_memcpy_u8(&pkt, data, (data == NULL) ? 0 : datalen) 609 || !WPACKET_get_total_written(&pkt, &hkdflabellen) 610 || !WPACKET_finish(&pkt)) { 611 WPACKET_cleanup(&pkt); 612 return 0; 613 } 614 615 return HKDF_Expand(md, key, keylen, hkdflabel, hkdflabellen, 616 out, outlen); 617} 618 619static int prov_tls13_hkdf_generate_secret(OSSL_LIB_CTX *libctx, 620 const EVP_MD *md, 621 const unsigned char *prevsecret, 622 size_t prevsecretlen, 623 const unsigned char *insecret, 624 size_t insecretlen, 625 const unsigned char *prefix, 626 size_t prefixlen, 627 const unsigned char *label, 628 size_t labellen, 629 unsigned char *out, size_t outlen) 630{ 631 size_t mdlen; 632 int ret; 633 unsigned char preextractsec[EVP_MAX_MD_SIZE]; 634 /* Always filled with zeros */ 635 static const unsigned char default_zeros[EVP_MAX_MD_SIZE]; 636 637 ret = EVP_MD_get_size(md); 638 /* Ensure cast to size_t is safe */ 639 if (ret <= 0) 640 return 0; 641 mdlen = (size_t)ret; 642 643 if (insecret == NULL) { 644 insecret = default_zeros; 645 insecretlen = mdlen; 646 } 647 if (prevsecret == NULL) { 648 prevsecret = default_zeros; 649 prevsecretlen = 0; 650 } else { 651 EVP_MD_CTX *mctx = EVP_MD_CTX_new(); 652 unsigned char hash[EVP_MAX_MD_SIZE]; 653 654 /* The pre-extract derive step uses a hash of no messages */ 655 if (mctx == NULL 656 || EVP_DigestInit_ex(mctx, md, NULL) <= 0 657 || EVP_DigestFinal_ex(mctx, hash, NULL) <= 0) { 658 EVP_MD_CTX_free(mctx); 659 return 0; 660 } 661 EVP_MD_CTX_free(mctx); 662 663 /* Generate the pre-extract secret */ 664 if (!prov_tls13_hkdf_expand(md, prevsecret, mdlen, 665 prefix, prefixlen, label, labellen, 666 hash, mdlen, preextractsec, mdlen)) 667 return 0; 668 prevsecret = preextractsec; 669 prevsecretlen = mdlen; 670 } 671 672 ret = HKDF_Extract(libctx, md, prevsecret, prevsecretlen, 673 insecret, insecretlen, out, outlen); 674 675 if (prevsecret == preextractsec) 676 OPENSSL_cleanse(preextractsec, mdlen); 677 return ret; 678} 679 680static int kdf_tls1_3_derive(void *vctx, unsigned char *key, size_t keylen, 681 const OSSL_PARAM params[]) 682{ 683 KDF_HKDF *ctx = (KDF_HKDF *)vctx; 684 const EVP_MD *md; 685 686 if (!ossl_prov_is_running() || !kdf_tls1_3_set_ctx_params(ctx, params)) 687 return 0; 688 689 md = ossl_prov_digest_md(&ctx->digest); 690 if (md == NULL) { 691 ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MESSAGE_DIGEST); 692 return 0; 693 } 694 695 switch (ctx->mode) { 696 default: 697 return 0; 698 699 case EVP_KDF_HKDF_MODE_EXTRACT_ONLY: 700 return prov_tls13_hkdf_generate_secret(PROV_LIBCTX_OF(ctx->provctx), 701 md, 702 ctx->salt, ctx->salt_len, 703 ctx->key, ctx->key_len, 704 ctx->prefix, ctx->prefix_len, 705 ctx->label, ctx->label_len, 706 key, keylen); 707 708 case EVP_KDF_HKDF_MODE_EXPAND_ONLY: 709 return prov_tls13_hkdf_expand(md, ctx->key, ctx->key_len, 710 ctx->prefix, ctx->prefix_len, 711 ctx->label, ctx->label_len, 712 ctx->data, ctx->data_len, 713 key, keylen); 714 } 715} 716 717static int kdf_tls1_3_set_ctx_params(void *vctx, const OSSL_PARAM params[]) 718{ 719 const OSSL_PARAM *p; 720 KDF_HKDF *ctx = vctx; 721 722 if (params == NULL) 723 return 1; 724 725 if (!hkdf_common_set_ctx_params(ctx, params)) 726 return 0; 727 728 if (ctx->mode == EVP_KDF_HKDF_MODE_EXTRACT_AND_EXPAND) { 729 ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_MODE); 730 return 0; 731 } 732 733 if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_PREFIX)) != NULL) { 734 OPENSSL_free(ctx->prefix); 735 ctx->prefix = NULL; 736 if (!OSSL_PARAM_get_octet_string(p, (void **)&ctx->prefix, 0, 737 &ctx->prefix_len)) 738 return 0; 739 } 740 741 if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_LABEL)) != NULL) { 742 OPENSSL_free(ctx->label); 743 ctx->label = NULL; 744 if (!OSSL_PARAM_get_octet_string(p, (void **)&ctx->label, 0, 745 &ctx->label_len)) 746 return 0; 747 } 748 749 OPENSSL_clear_free(ctx->data, ctx->data_len); 750 ctx->data = NULL; 751 if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_DATA)) != NULL 752 && !OSSL_PARAM_get_octet_string(p, (void **)&ctx->data, 0, 753 &ctx->data_len)) 754 return 0; 755 return 1; 756} 757 758static const OSSL_PARAM *kdf_tls1_3_settable_ctx_params(ossl_unused void *ctx, 759 ossl_unused void *provctx) 760{ 761 static const OSSL_PARAM known_settable_ctx_params[] = { 762 HKDF_COMMON_SETTABLES, 763 OSSL_PARAM_octet_string(OSSL_KDF_PARAM_PREFIX, NULL, 0), 764 OSSL_PARAM_octet_string(OSSL_KDF_PARAM_LABEL, NULL, 0), 765 OSSL_PARAM_octet_string(OSSL_KDF_PARAM_DATA, NULL, 0), 766 OSSL_PARAM_END 767 }; 768 return known_settable_ctx_params; 769} 770 771const OSSL_DISPATCH ossl_kdf_tls1_3_kdf_functions[] = { 772 { OSSL_FUNC_KDF_NEWCTX, (void(*)(void))kdf_hkdf_new }, 773 { OSSL_FUNC_KDF_FREECTX, (void(*)(void))kdf_hkdf_free }, 774 { OSSL_FUNC_KDF_RESET, (void(*)(void))kdf_hkdf_reset }, 775 { OSSL_FUNC_KDF_DERIVE, (void(*)(void))kdf_tls1_3_derive }, 776 { OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS, 777 (void(*)(void))kdf_tls1_3_settable_ctx_params }, 778 { OSSL_FUNC_KDF_SET_CTX_PARAMS, (void(*)(void))kdf_tls1_3_set_ctx_params }, 779 { OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS, 780 (void(*)(void))kdf_hkdf_gettable_ctx_params }, 781 { OSSL_FUNC_KDF_GET_CTX_PARAMS, (void(*)(void))kdf_hkdf_get_ctx_params }, 782 { 0, NULL } 783}; 784