1 /* 2 * The LMS stateful-hash public-key signature scheme 3 * 4 * Copyright The Mbed TLS Contributors 5 * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later 6 */ 7 8 /* 9 * The following sources were referenced in the design of this implementation 10 * of the LMS algorithm: 11 * 12 * [1] IETF RFC8554 13 * D. McGrew, M. Curcio, S.Fluhrer 14 * https://datatracker.ietf.org/doc/html/rfc8554 15 * 16 * [2] NIST Special Publication 800-208 17 * David A. Cooper et. al. 18 * https://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-208.pdf 19 */ 20 21 #include "common.h" 22 23 #if defined(MBEDTLS_LMS_C) 24 25 #include <string.h> 26 27 #include "lmots.h" 28 29 #include "psa/crypto.h" 30 #include "psa_util_internal.h" 31 #include "mbedtls/lms.h" 32 #include "mbedtls/error.h" 33 #include "mbedtls/platform_util.h" 34 35 #include "mbedtls/platform.h" 36 37 /* Define a local translating function to save code size by not using too many 38 * arguments in each translating place. */ 39 static int local_err_translation(psa_status_t status) 40 { 41 return psa_status_to_mbedtls(status, psa_to_lms_errors, 42 ARRAY_LENGTH(psa_to_lms_errors), 43 psa_generic_status_to_mbedtls); 44 } 45 #define PSA_TO_MBEDTLS_ERR(status) local_err_translation(status) 46 47 #define SIG_Q_LEAF_ID_OFFSET (0) 48 #define SIG_OTS_SIG_OFFSET (SIG_Q_LEAF_ID_OFFSET + \ 49 MBEDTLS_LMOTS_Q_LEAF_ID_LEN) 50 #define SIG_TYPE_OFFSET(otstype) (SIG_OTS_SIG_OFFSET + \ 51 MBEDTLS_LMOTS_SIG_LEN(otstype)) 52 #define SIG_PATH_OFFSET(otstype) (SIG_TYPE_OFFSET(otstype) + \ 53 MBEDTLS_LMS_TYPE_LEN) 54 55 #define PUBLIC_KEY_TYPE_OFFSET (0) 56 #define PUBLIC_KEY_OTSTYPE_OFFSET (PUBLIC_KEY_TYPE_OFFSET + \ 57 MBEDTLS_LMS_TYPE_LEN) 58 #define PUBLIC_KEY_I_KEY_ID_OFFSET (PUBLIC_KEY_OTSTYPE_OFFSET + \ 59 MBEDTLS_LMOTS_TYPE_LEN) 60 #define PUBLIC_KEY_ROOT_NODE_OFFSET (PUBLIC_KEY_I_KEY_ID_OFFSET + \ 61 MBEDTLS_LMOTS_I_KEY_ID_LEN) 62 63 64 /* Currently only support H=10 */ 65 #define H_TREE_HEIGHT_MAX 10 66 #define MERKLE_TREE_NODE_AM(type) ((size_t) 1 << (MBEDTLS_LMS_H_TREE_HEIGHT(type) + 1u)) 67 #define MERKLE_TREE_LEAF_NODE_AM(type) ((size_t) 1 << MBEDTLS_LMS_H_TREE_HEIGHT(type)) 68 #define MERKLE_TREE_INTERNAL_NODE_AM(type) ((unsigned int) \ 69 (1u << MBEDTLS_LMS_H_TREE_HEIGHT(type))) 70 71 #define D_CONST_LEN (2) 72 static const unsigned char D_LEAF_CONSTANT_BYTES[D_CONST_LEN] = { 0x82, 0x82 }; 73 static const unsigned char D_INTR_CONSTANT_BYTES[D_CONST_LEN] = { 0x83, 0x83 }; 74 75 76 /* Calculate the value of a leaf node of the Merkle tree (which is a hash of a 77 * public key and some other parameters like the leaf index). This function 78 * implements RFC8554 section 5.3, in the case where r >= 2^h. 79 * 80 * params The LMS parameter set, the underlying LMOTS 81 * parameter set, and I value which describe the key 82 * being used. 83 * 84 * pub_key The public key of the private whose index 85 * corresponds to the index of this leaf node. This 86 * is a hash output. 87 * 88 * r_node_idx The index of this node in the Merkle tree. Note 89 * that the root node of the Merkle tree is 90 * 1-indexed. 91 * 92 * out The output node value, which is a hash output. 93 */ 94 static int create_merkle_leaf_value(const mbedtls_lms_parameters_t *params, 95 unsigned char *pub_key, 96 unsigned int r_node_idx, 97 unsigned char *out) 98 { 99 psa_hash_operation_t op; 100 psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; 101 size_t output_hash_len; 102 unsigned char r_node_idx_bytes[4]; 103 104 op = psa_hash_operation_init(); 105 status = psa_hash_setup(&op, PSA_ALG_SHA_256); 106 if (status != PSA_SUCCESS) { 107 goto exit; 108 } 109 110 status = psa_hash_update(&op, params->I_key_identifier, 111 MBEDTLS_LMOTS_I_KEY_ID_LEN); 112 if (status != PSA_SUCCESS) { 113 goto exit; 114 } 115 116 MBEDTLS_PUT_UINT32_BE(r_node_idx, r_node_idx_bytes, 0); 117 status = psa_hash_update(&op, r_node_idx_bytes, 4); 118 if (status != PSA_SUCCESS) { 119 goto exit; 120 } 121 122 status = psa_hash_update(&op, D_LEAF_CONSTANT_BYTES, D_CONST_LEN); 123 if (status != PSA_SUCCESS) { 124 goto exit; 125 } 126 127 status = psa_hash_update(&op, pub_key, 128 MBEDTLS_LMOTS_N_HASH_LEN(params->otstype)); 129 if (status != PSA_SUCCESS) { 130 goto exit; 131 } 132 133 status = psa_hash_finish(&op, out, MBEDTLS_LMS_M_NODE_BYTES(params->type), 134 &output_hash_len); 135 if (status != PSA_SUCCESS) { 136 goto exit; 137 } 138 139 exit: 140 psa_hash_abort(&op); 141 142 return PSA_TO_MBEDTLS_ERR(status); 143 } 144 145 /* Calculate the value of an internal node of the Merkle tree (which is a hash 146 * of a public key and some other parameters like the node index). This function 147 * implements RFC8554 section 5.3, in the case where r < 2^h. 148 * 149 * params The LMS parameter set, the underlying LMOTS 150 * parameter set, and I value which describe the key 151 * being used. 152 * 153 * left_node The value of the child of this node which is on 154 * the left-hand side. As with all nodes on the 155 * Merkle tree, this is a hash output. 156 * 157 * right_node The value of the child of this node which is on 158 * the right-hand side. As with all nodes on the 159 * Merkle tree, this is a hash output. 160 * 161 * r_node_idx The index of this node in the Merkle tree. Note 162 * that the root node of the Merkle tree is 163 * 1-indexed. 164 * 165 * out The output node value, which is a hash output. 166 */ 167 static int create_merkle_internal_value(const mbedtls_lms_parameters_t *params, 168 const unsigned char *left_node, 169 const unsigned char *right_node, 170 unsigned int r_node_idx, 171 unsigned char *out) 172 { 173 psa_hash_operation_t op; 174 psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; 175 size_t output_hash_len; 176 unsigned char r_node_idx_bytes[4]; 177 178 op = psa_hash_operation_init(); 179 status = psa_hash_setup(&op, PSA_ALG_SHA_256); 180 if (status != PSA_SUCCESS) { 181 goto exit; 182 } 183 184 status = psa_hash_update(&op, params->I_key_identifier, 185 MBEDTLS_LMOTS_I_KEY_ID_LEN); 186 if (status != PSA_SUCCESS) { 187 goto exit; 188 } 189 190 MBEDTLS_PUT_UINT32_BE(r_node_idx, r_node_idx_bytes, 0); 191 status = psa_hash_update(&op, r_node_idx_bytes, 4); 192 if (status != PSA_SUCCESS) { 193 goto exit; 194 } 195 196 status = psa_hash_update(&op, D_INTR_CONSTANT_BYTES, D_CONST_LEN); 197 if (status != PSA_SUCCESS) { 198 goto exit; 199 } 200 201 status = psa_hash_update(&op, left_node, 202 MBEDTLS_LMS_M_NODE_BYTES(params->type)); 203 if (status != PSA_SUCCESS) { 204 goto exit; 205 } 206 207 status = psa_hash_update(&op, right_node, 208 MBEDTLS_LMS_M_NODE_BYTES(params->type)); 209 if (status != PSA_SUCCESS) { 210 goto exit; 211 } 212 213 status = psa_hash_finish(&op, out, MBEDTLS_LMS_M_NODE_BYTES(params->type), 214 &output_hash_len); 215 if (status != PSA_SUCCESS) { 216 goto exit; 217 } 218 219 exit: 220 psa_hash_abort(&op); 221 222 return PSA_TO_MBEDTLS_ERR(status); 223 } 224 225 void mbedtls_lms_public_init(mbedtls_lms_public_t *ctx) 226 { 227 memset(ctx, 0, sizeof(*ctx)); 228 } 229 230 void mbedtls_lms_public_free(mbedtls_lms_public_t *ctx) 231 { 232 if (ctx == NULL) { 233 return; 234 } 235 236 mbedtls_platform_zeroize(ctx, sizeof(*ctx)); 237 } 238 239 int mbedtls_lms_import_public_key(mbedtls_lms_public_t *ctx, 240 const unsigned char *key, size_t key_size) 241 { 242 mbedtls_lms_algorithm_type_t type; 243 mbedtls_lmots_algorithm_type_t otstype; 244 245 type = (mbedtls_lms_algorithm_type_t) MBEDTLS_GET_UINT32_BE(key, PUBLIC_KEY_TYPE_OFFSET); 246 if (type != MBEDTLS_LMS_SHA256_M32_H10) { 247 return MBEDTLS_ERR_LMS_BAD_INPUT_DATA; 248 } 249 ctx->params.type = type; 250 251 if (key_size != MBEDTLS_LMS_PUBLIC_KEY_LEN(ctx->params.type)) { 252 return MBEDTLS_ERR_LMS_BAD_INPUT_DATA; 253 } 254 255 otstype = (mbedtls_lmots_algorithm_type_t) 256 MBEDTLS_GET_UINT32_BE(key, PUBLIC_KEY_OTSTYPE_OFFSET); 257 if (otstype != MBEDTLS_LMOTS_SHA256_N32_W8) { 258 return MBEDTLS_ERR_LMS_BAD_INPUT_DATA; 259 } 260 ctx->params.otstype = otstype; 261 262 memcpy(ctx->params.I_key_identifier, 263 key + PUBLIC_KEY_I_KEY_ID_OFFSET, 264 MBEDTLS_LMOTS_I_KEY_ID_LEN); 265 memcpy(ctx->T_1_pub_key, key + PUBLIC_KEY_ROOT_NODE_OFFSET, 266 MBEDTLS_LMS_M_NODE_BYTES(ctx->params.type)); 267 268 ctx->have_public_key = 1; 269 270 return 0; 271 } 272 273 int mbedtls_lms_export_public_key(const mbedtls_lms_public_t *ctx, 274 unsigned char *key, 275 size_t key_size, size_t *key_len) 276 { 277 if (key_size < MBEDTLS_LMS_PUBLIC_KEY_LEN(ctx->params.type)) { 278 return MBEDTLS_ERR_LMS_BUFFER_TOO_SMALL; 279 } 280 281 if (!ctx->have_public_key) { 282 return MBEDTLS_ERR_LMS_BAD_INPUT_DATA; 283 } 284 285 MBEDTLS_PUT_UINT32_BE(ctx->params.type, key, PUBLIC_KEY_TYPE_OFFSET); 286 MBEDTLS_PUT_UINT32_BE(ctx->params.otstype, key, PUBLIC_KEY_OTSTYPE_OFFSET); 287 memcpy(key + PUBLIC_KEY_I_KEY_ID_OFFSET, 288 ctx->params.I_key_identifier, 289 MBEDTLS_LMOTS_I_KEY_ID_LEN); 290 memcpy(key +PUBLIC_KEY_ROOT_NODE_OFFSET, 291 ctx->T_1_pub_key, 292 MBEDTLS_LMS_M_NODE_BYTES(ctx->params.type)); 293 294 if (key_len != NULL) { 295 *key_len = MBEDTLS_LMS_PUBLIC_KEY_LEN(ctx->params.type); 296 } 297 298 return 0; 299 } 300 301 int mbedtls_lms_verify(const mbedtls_lms_public_t *ctx, 302 const unsigned char *msg, size_t msg_size, 303 const unsigned char *sig, size_t sig_size) 304 { 305 unsigned int q_leaf_identifier; 306 unsigned char Kc_candidate_ots_pub_key[MBEDTLS_LMOTS_N_HASH_LEN_MAX]; 307 unsigned char Tc_candidate_root_node[MBEDTLS_LMS_M_NODE_BYTES_MAX]; 308 unsigned int height; 309 unsigned int curr_node_id; 310 unsigned int parent_node_id; 311 const unsigned char *left_node; 312 const unsigned char *right_node; 313 mbedtls_lmots_parameters_t ots_params; 314 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 315 316 if (!ctx->have_public_key) { 317 return MBEDTLS_ERR_LMS_BAD_INPUT_DATA; 318 } 319 320 if (ctx->params.type 321 != MBEDTLS_LMS_SHA256_M32_H10) { 322 return MBEDTLS_ERR_LMS_BAD_INPUT_DATA; 323 } 324 325 if (ctx->params.otstype 326 != MBEDTLS_LMOTS_SHA256_N32_W8) { 327 return MBEDTLS_ERR_LMS_BAD_INPUT_DATA; 328 } 329 330 if (sig_size != MBEDTLS_LMS_SIG_LEN(ctx->params.type, ctx->params.otstype)) { 331 return MBEDTLS_ERR_LMS_VERIFY_FAILED; 332 } 333 334 if (sig_size < SIG_OTS_SIG_OFFSET + MBEDTLS_LMOTS_TYPE_LEN) { 335 return MBEDTLS_ERR_LMS_VERIFY_FAILED; 336 } 337 338 if (MBEDTLS_GET_UINT32_BE(sig, SIG_OTS_SIG_OFFSET + MBEDTLS_LMOTS_SIG_TYPE_OFFSET) 339 != MBEDTLS_LMOTS_SHA256_N32_W8) { 340 return MBEDTLS_ERR_LMS_VERIFY_FAILED; 341 } 342 343 if (sig_size < SIG_TYPE_OFFSET(ctx->params.otstype) + MBEDTLS_LMS_TYPE_LEN) { 344 return MBEDTLS_ERR_LMS_VERIFY_FAILED; 345 } 346 347 if (MBEDTLS_GET_UINT32_BE(sig, SIG_TYPE_OFFSET(ctx->params.otstype)) 348 != MBEDTLS_LMS_SHA256_M32_H10) { 349 return MBEDTLS_ERR_LMS_VERIFY_FAILED; 350 } 351 352 353 q_leaf_identifier = MBEDTLS_GET_UINT32_BE(sig, SIG_Q_LEAF_ID_OFFSET); 354 355 if (q_leaf_identifier >= MERKLE_TREE_LEAF_NODE_AM(ctx->params.type)) { 356 return MBEDTLS_ERR_LMS_VERIFY_FAILED; 357 } 358 359 memcpy(ots_params.I_key_identifier, 360 ctx->params.I_key_identifier, 361 MBEDTLS_LMOTS_I_KEY_ID_LEN); 362 MBEDTLS_PUT_UINT32_BE(q_leaf_identifier, ots_params.q_leaf_identifier, 0); 363 ots_params.type = ctx->params.otstype; 364 365 ret = mbedtls_lmots_calculate_public_key_candidate(&ots_params, 366 msg, 367 msg_size, 368 sig + SIG_OTS_SIG_OFFSET, 369 MBEDTLS_LMOTS_SIG_LEN(ctx->params.otstype), 370 Kc_candidate_ots_pub_key, 371 sizeof(Kc_candidate_ots_pub_key), 372 NULL); 373 if (ret != 0) { 374 return MBEDTLS_ERR_LMS_VERIFY_FAILED; 375 } 376 377 create_merkle_leaf_value( 378 &ctx->params, 379 Kc_candidate_ots_pub_key, 380 MERKLE_TREE_INTERNAL_NODE_AM(ctx->params.type) + q_leaf_identifier, 381 Tc_candidate_root_node); 382 383 curr_node_id = MERKLE_TREE_INTERNAL_NODE_AM(ctx->params.type) + 384 q_leaf_identifier; 385 386 for (height = 0; height < MBEDTLS_LMS_H_TREE_HEIGHT(ctx->params.type); 387 height++) { 388 parent_node_id = curr_node_id / 2; 389 390 /* Left/right node ordering matters for the hash */ 391 if (curr_node_id & 1) { 392 left_node = sig + SIG_PATH_OFFSET(ctx->params.otstype) + 393 height * MBEDTLS_LMS_M_NODE_BYTES(ctx->params.type); 394 right_node = Tc_candidate_root_node; 395 } else { 396 left_node = Tc_candidate_root_node; 397 right_node = sig + SIG_PATH_OFFSET(ctx->params.otstype) + 398 height * MBEDTLS_LMS_M_NODE_BYTES(ctx->params.type); 399 } 400 401 create_merkle_internal_value(&ctx->params, left_node, right_node, 402 parent_node_id, Tc_candidate_root_node); 403 404 curr_node_id /= 2; 405 } 406 407 if (memcmp(Tc_candidate_root_node, ctx->T_1_pub_key, 408 MBEDTLS_LMS_M_NODE_BYTES(ctx->params.type))) { 409 return MBEDTLS_ERR_LMS_VERIFY_FAILED; 410 } 411 412 return 0; 413 } 414 415 #if defined(MBEDTLS_LMS_PRIVATE) 416 417 /* Calculate a full Merkle tree based on a private key. This function 418 * implements RFC8554 section 5.3, and is used to generate a public key (as the 419 * public key is the root node of the Merkle tree). 420 * 421 * ctx The LMS private context, containing a parameter 422 * set and private key material consisting of both 423 * public and private OTS. 424 * 425 * tree The output tree, which is 2^(H + 1) hash outputs. 426 * In the case of H=10 we have 2048 tree nodes (of 427 * which 1024 of them are leaf nodes). Note that 428 * because the Merkle tree root is 1-indexed, the 0 429 * index tree node is never used. 430 */ 431 static int calculate_merkle_tree(const mbedtls_lms_private_t *ctx, 432 unsigned char *tree) 433 { 434 unsigned int priv_key_idx; 435 unsigned int r_node_idx; 436 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 437 438 /* First create the leaf nodes, in ascending order */ 439 for (priv_key_idx = 0; 440 priv_key_idx < MERKLE_TREE_INTERNAL_NODE_AM(ctx->params.type); 441 priv_key_idx++) { 442 r_node_idx = MERKLE_TREE_INTERNAL_NODE_AM(ctx->params.type) + priv_key_idx; 443 444 ret = create_merkle_leaf_value(&ctx->params, 445 ctx->ots_public_keys[priv_key_idx].public_key, 446 r_node_idx, 447 &tree[r_node_idx * MBEDTLS_LMS_M_NODE_BYTES( 448 ctx->params.type)]); 449 if (ret != 0) { 450 return ret; 451 } 452 } 453 454 /* Then the internal nodes, in reverse order so that we can guarantee the 455 * parent has been created */ 456 for (r_node_idx = MERKLE_TREE_INTERNAL_NODE_AM(ctx->params.type) - 1; 457 r_node_idx > 0; 458 r_node_idx--) { 459 ret = create_merkle_internal_value(&ctx->params, 460 &tree[(r_node_idx * 2) * 461 MBEDTLS_LMS_M_NODE_BYTES(ctx->params.type)], 462 &tree[(r_node_idx * 2 + 1) * 463 MBEDTLS_LMS_M_NODE_BYTES(ctx->params.type)], 464 r_node_idx, 465 &tree[r_node_idx * 466 MBEDTLS_LMS_M_NODE_BYTES(ctx->params.type)]); 467 if (ret != 0) { 468 return ret; 469 } 470 } 471 472 return 0; 473 } 474 475 /* Calculate a path from a leaf node of the Merkle tree to the root of the tree, 476 * and return the full path. This function implements RFC8554 section 5.4.1, as 477 * the Merkle path is the main component of an LMS signature. 478 * 479 * ctx The LMS private context, containing a parameter 480 * set and private key material consisting of both 481 * public and private OTS. 482 * 483 * leaf_node_id Which leaf node to calculate the path from. 484 * 485 * path The output path, which is H hash outputs. 486 */ 487 static int get_merkle_path(mbedtls_lms_private_t *ctx, 488 unsigned int leaf_node_id, 489 unsigned char *path) 490 { 491 const size_t node_bytes = MBEDTLS_LMS_M_NODE_BYTES(ctx->params.type); 492 unsigned int curr_node_id = leaf_node_id; 493 unsigned int adjacent_node_id; 494 unsigned char *tree = NULL; 495 unsigned int height; 496 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 497 498 tree = mbedtls_calloc((size_t) MERKLE_TREE_NODE_AM(ctx->params.type), 499 node_bytes); 500 if (tree == NULL) { 501 return MBEDTLS_ERR_LMS_ALLOC_FAILED; 502 } 503 504 ret = calculate_merkle_tree(ctx, tree); 505 if (ret != 0) { 506 goto exit; 507 } 508 509 for (height = 0; height < MBEDTLS_LMS_H_TREE_HEIGHT(ctx->params.type); 510 height++) { 511 adjacent_node_id = curr_node_id ^ 1; 512 513 memcpy(&path[height * node_bytes], 514 &tree[adjacent_node_id * node_bytes], node_bytes); 515 516 curr_node_id >>= 1; 517 } 518 519 ret = 0; 520 521 exit: 522 mbedtls_zeroize_and_free(tree, node_bytes * 523 (size_t) MERKLE_TREE_NODE_AM(ctx->params.type)); 524 525 return ret; 526 } 527 528 void mbedtls_lms_private_init(mbedtls_lms_private_t *ctx) 529 { 530 memset(ctx, 0, sizeof(*ctx)); 531 } 532 533 void mbedtls_lms_private_free(mbedtls_lms_private_t *ctx) 534 { 535 if (ctx == NULL) { 536 return; 537 } 538 539 unsigned int idx; 540 541 if (ctx->have_private_key) { 542 if (ctx->ots_private_keys != NULL) { 543 for (idx = 0; idx < MERKLE_TREE_LEAF_NODE_AM(ctx->params.type); idx++) { 544 mbedtls_lmots_private_free(&ctx->ots_private_keys[idx]); 545 } 546 } 547 548 if (ctx->ots_public_keys != NULL) { 549 for (idx = 0; idx < MERKLE_TREE_LEAF_NODE_AM(ctx->params.type); idx++) { 550 mbedtls_lmots_public_free(&ctx->ots_public_keys[idx]); 551 } 552 } 553 554 mbedtls_free(ctx->ots_private_keys); 555 mbedtls_free(ctx->ots_public_keys); 556 } 557 558 mbedtls_platform_zeroize(ctx, sizeof(*ctx)); 559 } 560 561 562 int mbedtls_lms_generate_private_key(mbedtls_lms_private_t *ctx, 563 mbedtls_lms_algorithm_type_t type, 564 mbedtls_lmots_algorithm_type_t otstype, 565 int (*f_rng)(void *, unsigned char *, size_t), 566 void *p_rng, const unsigned char *seed, 567 size_t seed_size) 568 { 569 unsigned int idx = 0; 570 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 571 572 if (type != MBEDTLS_LMS_SHA256_M32_H10) { 573 return MBEDTLS_ERR_LMS_BAD_INPUT_DATA; 574 } 575 576 if (otstype != MBEDTLS_LMOTS_SHA256_N32_W8) { 577 return MBEDTLS_ERR_LMS_BAD_INPUT_DATA; 578 } 579 580 if (ctx->have_private_key) { 581 return MBEDTLS_ERR_LMS_BAD_INPUT_DATA; 582 } 583 584 ctx->params.type = type; 585 ctx->params.otstype = otstype; 586 ctx->have_private_key = 1; 587 588 ret = f_rng(p_rng, 589 ctx->params.I_key_identifier, 590 MBEDTLS_LMOTS_I_KEY_ID_LEN); 591 if (ret != 0) { 592 goto exit; 593 } 594 595 /* Requires a cast to size_t to avoid an implicit cast warning on certain 596 * platforms (particularly Windows) */ 597 ctx->ots_private_keys = mbedtls_calloc((size_t) MERKLE_TREE_LEAF_NODE_AM(ctx->params.type), 598 sizeof(*ctx->ots_private_keys)); 599 if (ctx->ots_private_keys == NULL) { 600 ret = MBEDTLS_ERR_LMS_ALLOC_FAILED; 601 goto exit; 602 } 603 604 /* Requires a cast to size_t to avoid an implicit cast warning on certain 605 * platforms (particularly Windows) */ 606 ctx->ots_public_keys = mbedtls_calloc((size_t) MERKLE_TREE_LEAF_NODE_AM(ctx->params.type), 607 sizeof(*ctx->ots_public_keys)); 608 if (ctx->ots_public_keys == NULL) { 609 ret = MBEDTLS_ERR_LMS_ALLOC_FAILED; 610 goto exit; 611 } 612 613 for (idx = 0; idx < MERKLE_TREE_LEAF_NODE_AM(ctx->params.type); idx++) { 614 mbedtls_lmots_private_init(&ctx->ots_private_keys[idx]); 615 mbedtls_lmots_public_init(&ctx->ots_public_keys[idx]); 616 } 617 618 619 for (idx = 0; idx < MERKLE_TREE_LEAF_NODE_AM(ctx->params.type); idx++) { 620 ret = mbedtls_lmots_generate_private_key(&ctx->ots_private_keys[idx], 621 otstype, 622 ctx->params.I_key_identifier, 623 idx, seed, seed_size); 624 if (ret != 0) { 625 goto exit; 626 } 627 628 ret = mbedtls_lmots_calculate_public_key(&ctx->ots_public_keys[idx], 629 &ctx->ots_private_keys[idx]); 630 if (ret != 0) { 631 goto exit; 632 } 633 } 634 635 ctx->q_next_usable_key = 0; 636 637 exit: 638 if (ret != 0) { 639 mbedtls_lms_private_free(ctx); 640 } 641 642 return ret; 643 } 644 645 int mbedtls_lms_calculate_public_key(mbedtls_lms_public_t *ctx, 646 const mbedtls_lms_private_t *priv_ctx) 647 { 648 const size_t node_bytes = MBEDTLS_LMS_M_NODE_BYTES(priv_ctx->params.type); 649 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 650 unsigned char *tree = NULL; 651 652 if (!priv_ctx->have_private_key) { 653 return MBEDTLS_ERR_LMS_BAD_INPUT_DATA; 654 } 655 656 if (priv_ctx->params.type 657 != MBEDTLS_LMS_SHA256_M32_H10) { 658 return MBEDTLS_ERR_LMS_BAD_INPUT_DATA; 659 } 660 661 if (priv_ctx->params.otstype 662 != MBEDTLS_LMOTS_SHA256_N32_W8) { 663 return MBEDTLS_ERR_LMS_BAD_INPUT_DATA; 664 } 665 666 tree = mbedtls_calloc((size_t) MERKLE_TREE_NODE_AM(priv_ctx->params.type), 667 node_bytes); 668 if (tree == NULL) { 669 return MBEDTLS_ERR_LMS_ALLOC_FAILED; 670 } 671 672 memcpy(&ctx->params, &priv_ctx->params, 673 sizeof(mbedtls_lmots_parameters_t)); 674 675 ret = calculate_merkle_tree(priv_ctx, tree); 676 if (ret != 0) { 677 goto exit; 678 } 679 680 /* Root node is always at position 1, due to 1-based indexing */ 681 memcpy(ctx->T_1_pub_key, &tree[node_bytes], node_bytes); 682 683 ctx->have_public_key = 1; 684 685 ret = 0; 686 687 exit: 688 mbedtls_zeroize_and_free(tree, node_bytes * 689 (size_t) MERKLE_TREE_NODE_AM(priv_ctx->params.type)); 690 691 return ret; 692 } 693 694 695 int mbedtls_lms_sign(mbedtls_lms_private_t *ctx, 696 int (*f_rng)(void *, unsigned char *, size_t), 697 void *p_rng, const unsigned char *msg, 698 unsigned int msg_size, unsigned char *sig, size_t sig_size, 699 size_t *sig_len) 700 { 701 uint32_t q_leaf_identifier; 702 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 703 704 if (!ctx->have_private_key) { 705 return MBEDTLS_ERR_LMS_BAD_INPUT_DATA; 706 } 707 708 if (sig_size < MBEDTLS_LMS_SIG_LEN(ctx->params.type, ctx->params.otstype)) { 709 return MBEDTLS_ERR_LMS_BUFFER_TOO_SMALL; 710 } 711 712 if (ctx->params.type != MBEDTLS_LMS_SHA256_M32_H10) { 713 return MBEDTLS_ERR_LMS_BAD_INPUT_DATA; 714 } 715 716 if (ctx->params.otstype 717 != MBEDTLS_LMOTS_SHA256_N32_W8) { 718 return MBEDTLS_ERR_LMS_BAD_INPUT_DATA; 719 } 720 721 if (ctx->q_next_usable_key >= MERKLE_TREE_LEAF_NODE_AM(ctx->params.type)) { 722 return MBEDTLS_ERR_LMS_OUT_OF_PRIVATE_KEYS; 723 } 724 725 726 q_leaf_identifier = ctx->q_next_usable_key; 727 /* This new value must _always_ be written back to the disk before the 728 * signature is returned. 729 */ 730 ctx->q_next_usable_key += 1; 731 732 if (MBEDTLS_LMS_SIG_LEN(ctx->params.type, ctx->params.otstype) 733 < SIG_OTS_SIG_OFFSET) { 734 return MBEDTLS_ERR_LMS_BAD_INPUT_DATA; 735 } 736 737 ret = mbedtls_lmots_sign(&ctx->ots_private_keys[q_leaf_identifier], 738 f_rng, 739 p_rng, 740 msg, 741 msg_size, 742 sig + SIG_OTS_SIG_OFFSET, 743 MBEDTLS_LMS_SIG_LEN(ctx->params.type, 744 ctx->params.otstype) - SIG_OTS_SIG_OFFSET, 745 NULL); 746 if (ret != 0) { 747 return ret; 748 } 749 750 MBEDTLS_PUT_UINT32_BE(ctx->params.type, sig, SIG_TYPE_OFFSET(ctx->params.otstype)); 751 MBEDTLS_PUT_UINT32_BE(q_leaf_identifier, sig, SIG_Q_LEAF_ID_OFFSET); 752 753 ret = get_merkle_path(ctx, 754 MERKLE_TREE_INTERNAL_NODE_AM(ctx->params.type) + q_leaf_identifier, 755 sig + SIG_PATH_OFFSET(ctx->params.otstype)); 756 if (ret != 0) { 757 return ret; 758 } 759 760 if (sig_len != NULL) { 761 *sig_len = MBEDTLS_LMS_SIG_LEN(ctx->params.type, ctx->params.otstype); 762 } 763 764 765 return 0; 766 } 767 768 #endif /* defined(MBEDTLS_LMS_PRIVATE) */ 769 #endif /* defined(MBEDTLS_LMS_C) */ 770