1 /* 2 * Copyright 2019-2026 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 /* Dispatch functions for gcm mode */ 11 12 #include <openssl/rand.h> 13 #include <openssl/proverr.h> 14 #include "prov/ciphercommon.h" 15 #include "prov/ciphercommon_gcm.h" 16 #include "prov/providercommon.h" 17 #include "prov/provider_ctx.h" 18 #include "internal/param_names.h" 19 #include "fips/fipsindicator.h" 20 21 static int gcm_tls_init(PROV_GCM_CTX *dat, unsigned char *aad, size_t aad_len); 22 static int gcm_tls_iv_set_fixed(PROV_GCM_CTX *ctx, unsigned char *iv, 23 size_t len); 24 static int gcm_tls_cipher(PROV_GCM_CTX *ctx, unsigned char *out, size_t *padlen, 25 const unsigned char *in, size_t len); 26 static int gcm_cipher_internal(PROV_GCM_CTX *ctx, unsigned char *out, 27 size_t *padlen, const unsigned char *in, 28 size_t len); 29 30 #ifdef FIPS_MODULE 31 static int gcm_fips_taglen_approved(size_t taglen) 32 { 33 return taglen == UNINITIALISED_SIZET || taglen == 4 || taglen == 8 34 || (taglen >= 12 && taglen <= GCM_TAG_MAX_SIZE); 35 } 36 #endif 37 38 /* 39 * Called from EVP_CipherInit when there is currently no context via 40 * the new_ctx() function 41 */ 42 void ossl_gcm_initctx(void *provctx, PROV_GCM_CTX *ctx, size_t keybits, 43 const PROV_GCM_HW *hw) 44 { 45 ctx->pad = 1; 46 ctx->mode = EVP_CIPH_GCM_MODE; 47 ctx->taglen = UNINITIALISED_SIZET; 48 ctx->tls_aad_len = UNINITIALISED_SIZET; 49 ctx->ivlen = (EVP_GCM_TLS_FIXED_IV_LEN + EVP_GCM_TLS_EXPLICIT_IV_LEN); 50 ctx->keylen = keybits / 8; 51 ctx->hw = hw; 52 ctx->libctx = PROV_LIBCTX_OF(provctx); 53 } 54 55 /* 56 * Called by EVP_CipherInit via the _einit and _dinit functions 57 */ 58 static int gcm_init(void *vctx, const unsigned char *key, size_t keylen, 59 const unsigned char *iv, size_t ivlen, 60 const OSSL_PARAM params[], int enc) 61 { 62 PROV_GCM_CTX *ctx = (PROV_GCM_CTX *)vctx; 63 64 if (!ossl_prov_is_running()) 65 return 0; 66 67 ctx->enc = enc; 68 69 if (iv != NULL) { 70 if (ivlen == 0 || ivlen > sizeof(ctx->iv)) { 71 ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_IV_LENGTH); 72 return 0; 73 } 74 ctx->ivlen = ivlen; 75 memcpy(ctx->iv, iv, ivlen); 76 ctx->iv_state = IV_STATE_BUFFERED; 77 } 78 79 if (key != NULL) { 80 if (keylen != ctx->keylen) { 81 ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_KEY_LENGTH); 82 return 0; 83 } 84 if (!ctx->hw->setkey(ctx, key, ctx->keylen)) 85 return 0; 86 ctx->tls_enc_records = 0; 87 } 88 return ossl_gcm_set_ctx_params(ctx, params); 89 } 90 91 int ossl_gcm_einit(void *vctx, const unsigned char *key, size_t keylen, 92 const unsigned char *iv, size_t ivlen, 93 const OSSL_PARAM params[]) 94 { 95 return gcm_init(vctx, key, keylen, iv, ivlen, params, 1); 96 } 97 98 int ossl_gcm_dinit(void *vctx, const unsigned char *key, size_t keylen, 99 const unsigned char *iv, size_t ivlen, 100 const OSSL_PARAM params[]) 101 { 102 return gcm_init(vctx, key, keylen, iv, ivlen, params, 0); 103 } 104 105 /* increment counter (64-bit int) by 1 */ 106 static void ctr64_inc(unsigned char *counter) 107 { 108 int n = 8; 109 unsigned char c; 110 111 do { 112 --n; 113 c = counter[n]; 114 ++c; 115 counter[n] = c; 116 if (c > 0) 117 return; 118 } while (n > 0); 119 } 120 121 static int getivgen(PROV_GCM_CTX *ctx, unsigned char *out, size_t olen) 122 { 123 if (!ctx->iv_gen 124 || !ctx->key_set 125 || !ctx->hw->setiv(ctx, ctx->iv, ctx->ivlen)) 126 return 0; 127 if (olen == 0 || olen > ctx->ivlen) 128 olen = ctx->ivlen; 129 memcpy(out, ctx->iv + ctx->ivlen - olen, olen); 130 /* 131 * Invocation field will be at least 8 bytes in size and so no need 132 * to check wrap around or increment more than last 8 bytes. 133 */ 134 ctr64_inc(ctx->iv + ctx->ivlen - 8); 135 ctx->iv_state = IV_STATE_COPIED; 136 return 1; 137 } 138 139 static int setivinv(PROV_GCM_CTX *ctx, unsigned char *in, size_t inl) 140 { 141 if (!ctx->iv_gen 142 || !ctx->key_set 143 || ctx->enc) 144 return 0; 145 146 memcpy(ctx->iv + ctx->ivlen - inl, in, inl); 147 if (!ctx->hw->setiv(ctx, ctx->iv, ctx->ivlen)) 148 return 0; 149 ctx->iv_state = IV_STATE_COPIED; 150 return 1; 151 } 152 153 int ossl_gcm_get_ctx_params(void *vctx, OSSL_PARAM params[]) 154 { 155 PROV_GCM_CTX *ctx = (PROV_GCM_CTX *)vctx; 156 OSSL_PARAM *p; 157 size_t sz; 158 int type; 159 160 for (p = params; p->key != NULL; p++) { 161 type = ossl_param_find_pidx(p->key); 162 switch (type) { 163 default: 164 break; 165 166 case PIDX_CIPHER_PARAM_IVLEN: 167 if (!OSSL_PARAM_set_size_t(p, ctx->ivlen)) { 168 ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER); 169 return 0; 170 } 171 break; 172 173 case PIDX_CIPHER_PARAM_KEYLEN: 174 if (!OSSL_PARAM_set_size_t(p, ctx->keylen)) { 175 ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER); 176 return 0; 177 } 178 break; 179 180 case PIDX_CIPHER_PARAM_AEAD_TAGLEN: { 181 size_t taglen = (ctx->taglen != UNINITIALISED_SIZET) ? ctx->taglen : GCM_TAG_MAX_SIZE; 182 183 if (!OSSL_PARAM_set_size_t(p, taglen)) { 184 ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER); 185 return 0; 186 } 187 } break; 188 189 case PIDX_CIPHER_PARAM_IV: 190 if (ctx->iv_state == IV_STATE_UNINITIALISED) 191 return 0; 192 if (ctx->ivlen > p->data_size) { 193 ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_IV_LENGTH); 194 return 0; 195 } 196 if (!OSSL_PARAM_set_octet_string(p, ctx->iv, ctx->ivlen) 197 && !OSSL_PARAM_set_octet_ptr(p, &ctx->iv, ctx->ivlen)) { 198 ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER); 199 return 0; 200 } 201 break; 202 203 case PIDX_CIPHER_PARAM_UPDATED_IV: 204 if (ctx->iv_state == IV_STATE_UNINITIALISED) 205 return 0; 206 if (ctx->ivlen > p->data_size) { 207 ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_IV_LENGTH); 208 return 0; 209 } 210 if (!OSSL_PARAM_set_octet_string(p, ctx->iv, ctx->ivlen) 211 && !OSSL_PARAM_set_octet_ptr(p, &ctx->iv, ctx->ivlen)) { 212 ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER); 213 return 0; 214 } 215 break; 216 217 case PIDX_CIPHER_PARAM_AEAD_TLS1_AAD_PAD: 218 if (!OSSL_PARAM_set_size_t(p, ctx->tls_aad_pad_sz)) { 219 ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER); 220 return 0; 221 } 222 break; 223 224 case PIDX_CIPHER_PARAM_AEAD_TAG: 225 sz = p->data_size; 226 if (sz == 0 227 || sz > EVP_GCM_TLS_TAG_LEN 228 || !ctx->enc 229 || ctx->taglen == UNINITIALISED_SIZET) { 230 ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_TAG); 231 return 0; 232 } 233 if (!OSSL_PARAM_set_octet_string(p, ctx->buf, sz)) { 234 ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER); 235 return 0; 236 } 237 break; 238 239 case PIDX_CIPHER_PARAM_AEAD_TLS1_GET_IV_GEN: 240 if (p->data == NULL 241 || p->data_type != OSSL_PARAM_OCTET_STRING 242 || !getivgen(ctx, p->data, p->data_size)) 243 return 0; 244 break; 245 case PIDX_CIPHER_PARAM_AEAD_IV_GENERATED: 246 if (!OSSL_PARAM_set_uint(p, ctx->iv_gen_rand)) 247 return 0; 248 } 249 } 250 #ifdef FIPS_MODULE 251 /* Externally supplied IVs are permitted but not approved for encryption. */ 252 return ossl_FIPS_IND_get_ctx_param_conditional(NULL, params, 253 (!ctx->enc || ctx->iv_gen_rand) 254 && gcm_fips_taglen_approved(ctx->taglen)); 255 #else 256 return 1; 257 #endif 258 } 259 260 int ossl_gcm_set_ctx_params(void *vctx, const OSSL_PARAM params[]) 261 { 262 PROV_GCM_CTX *ctx = (PROV_GCM_CTX *)vctx; 263 const OSSL_PARAM *p; 264 size_t sz; 265 void *vp; 266 int type; 267 268 if (ossl_param_is_empty(params)) 269 return 1; 270 271 for (p = params; p->key != NULL; p++) { 272 type = ossl_param_find_pidx(p->key); 273 switch (type) { 274 default: 275 break; 276 277 case PIDX_CIPHER_PARAM_AEAD_TAG: 278 vp = ctx->buf; 279 if (!OSSL_PARAM_get_octet_string(p, &vp, EVP_GCM_TLS_TAG_LEN, &sz)) { 280 ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_GET_PARAMETER); 281 return 0; 282 } 283 if (sz == 0 || ctx->enc) { 284 ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_TAG); 285 return 0; 286 } 287 ctx->taglen = sz; 288 break; 289 290 case PIDX_CIPHER_PARAM_AEAD_IVLEN: 291 if (!OSSL_PARAM_get_size_t(p, &sz)) { 292 ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_GET_PARAMETER); 293 return 0; 294 } 295 if (sz == 0 || sz > sizeof(ctx->iv)) { 296 ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_IV_LENGTH); 297 return 0; 298 } 299 if (ctx->ivlen != sz) { 300 /* If the iv was already set or autogenerated, it is invalid. */ 301 if (ctx->iv_state != IV_STATE_UNINITIALISED) 302 ctx->iv_state = IV_STATE_FINISHED; 303 ctx->ivlen = sz; 304 } 305 break; 306 307 case PIDX_CIPHER_PARAM_AEAD_TLS1_AAD: 308 if (p->data_type != OSSL_PARAM_OCTET_STRING) { 309 ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_GET_PARAMETER); 310 return 0; 311 } 312 sz = gcm_tls_init(ctx, p->data, p->data_size); 313 if (sz == 0) { 314 ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_AAD); 315 return 0; 316 } 317 ctx->tls_aad_pad_sz = sz; 318 break; 319 320 case PIDX_CIPHER_PARAM_AEAD_TLS1_IV_FIXED: 321 if (p->data_type != OSSL_PARAM_OCTET_STRING) { 322 ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_GET_PARAMETER); 323 return 0; 324 } 325 if (gcm_tls_iv_set_fixed(ctx, p->data, p->data_size) == 0) { 326 ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_GET_PARAMETER); 327 return 0; 328 } 329 break; 330 331 case PIDX_CIPHER_PARAM_AEAD_TLS1_SET_IV_INV: 332 if (p->data == NULL 333 || p->data_type != OSSL_PARAM_OCTET_STRING 334 || !setivinv(ctx, p->data, p->data_size)) 335 return 0; 336 break; 337 } 338 } 339 340 return 1; 341 } 342 343 int ossl_gcm_stream_update(void *vctx, unsigned char *out, size_t *outl, 344 size_t outsize, const unsigned char *in, size_t inl) 345 { 346 PROV_GCM_CTX *ctx = (PROV_GCM_CTX *)vctx; 347 348 if (inl == 0) { 349 *outl = 0; 350 return 1; 351 } 352 353 if (outsize < inl) { 354 ERR_raise(ERR_LIB_PROV, PROV_R_OUTPUT_BUFFER_TOO_SMALL); 355 return 0; 356 } 357 358 if (gcm_cipher_internal(ctx, out, outl, in, inl) <= 0) { 359 ERR_raise(ERR_LIB_PROV, PROV_R_CIPHER_OPERATION_FAILED); 360 return 0; 361 } 362 return 1; 363 } 364 365 int ossl_gcm_stream_final(void *vctx, unsigned char *out, size_t *outl, 366 size_t outsize) 367 { 368 PROV_GCM_CTX *ctx = (PROV_GCM_CTX *)vctx; 369 int i; 370 371 if (!ossl_prov_is_running()) 372 return 0; 373 374 i = gcm_cipher_internal(ctx, out, outl, NULL, 0); 375 if (i <= 0) 376 return 0; 377 378 *outl = 0; 379 return 1; 380 } 381 382 int ossl_gcm_cipher(void *vctx, 383 unsigned char *out, size_t *outl, size_t outsize, 384 const unsigned char *in, size_t inl) 385 { 386 PROV_GCM_CTX *ctx = (PROV_GCM_CTX *)vctx; 387 388 if (!ossl_prov_is_running()) 389 return 0; 390 391 if (outsize < inl) { 392 ERR_raise(ERR_LIB_PROV, PROV_R_OUTPUT_BUFFER_TOO_SMALL); 393 return 0; 394 } 395 396 if (gcm_cipher_internal(ctx, out, outl, in, inl) <= 0) 397 return 0; 398 399 *outl = inl; 400 return 1; 401 } 402 403 /* 404 * See SP800-38D (GCM) Section 8 "Uniqueness requirement on IVS and keys" 405 * 406 * See also 8.2.2 RBG-based construction. 407 * Random construction consists of a free field (which can be NULL) and a 408 * random field which will use a DRBG that can return at least 96 bits of 409 * entropy strength. (The DRBG must be seeded by the FIPS module). 410 */ 411 static int gcm_iv_generate(PROV_GCM_CTX *ctx, int offset) 412 { 413 int sz = ctx->ivlen - offset; 414 415 /* Must be at least 96 bits */ 416 if (sz <= 0 || ctx->ivlen < GCM_IV_DEFAULT_SIZE) 417 return 0; 418 419 /* Use DRBG to generate random iv */ 420 if (RAND_bytes_ex(ctx->libctx, ctx->iv + offset, sz, 0) <= 0) 421 return 0; 422 ctx->iv_state = IV_STATE_BUFFERED; 423 ctx->iv_gen_rand = 1; 424 return 1; 425 } 426 427 static int gcm_cipher_internal(PROV_GCM_CTX *ctx, unsigned char *out, 428 size_t *padlen, const unsigned char *in, 429 size_t len) 430 { 431 size_t olen = 0; 432 int rv = 0; 433 const PROV_GCM_HW *hw = ctx->hw; 434 435 if (ctx->tls_aad_len != UNINITIALISED_SIZET) 436 return gcm_tls_cipher(ctx, out, padlen, in, len); 437 438 if (!ctx->key_set || ctx->iv_state == IV_STATE_FINISHED) 439 goto err; 440 441 /* 442 * FIPS requires generation of AES-GCM IV's inside the FIPS module. 443 * The IV can still be set externally (the security policy will state that 444 * this is not FIPS compliant). There are some applications 445 * where setting the IV externally is the only option available. 446 */ 447 if (ctx->iv_state == IV_STATE_UNINITIALISED) { 448 if (!ctx->enc || !gcm_iv_generate(ctx, 0)) 449 goto err; 450 } 451 452 if (ctx->iv_state == IV_STATE_BUFFERED) { 453 if (!hw->setiv(ctx, ctx->iv, ctx->ivlen)) 454 goto err; 455 ctx->iv_state = IV_STATE_COPIED; 456 } 457 458 if (in != NULL) { 459 /* The input is AAD if out is NULL */ 460 if (out == NULL) { 461 if (!hw->aadupdate(ctx, in, len)) 462 goto err; 463 } else { 464 /* The input is ciphertext OR plaintext */ 465 if (!hw->cipherupdate(ctx, in, len, out)) 466 goto err; 467 } 468 } else { 469 /* The tag must be set before actually decrypting data */ 470 if (!ctx->enc && ctx->taglen == UNINITIALISED_SIZET) 471 goto err; 472 if (!hw->cipherfinal(ctx, ctx->buf)) 473 goto err; 474 ctx->iv_state = IV_STATE_FINISHED; /* Don't reuse the IV */ 475 goto finish; 476 } 477 olen = len; 478 finish: 479 rv = 1; 480 err: 481 *padlen = olen; 482 return rv; 483 } 484 485 static int gcm_tls_init(PROV_GCM_CTX *dat, unsigned char *aad, size_t aad_len) 486 { 487 unsigned char *buf; 488 size_t len; 489 490 if (!ossl_prov_is_running() || aad_len != EVP_AEAD_TLS1_AAD_LEN) 491 return 0; 492 493 /* Save the aad for later use. */ 494 buf = dat->buf; 495 memcpy(buf, aad, aad_len); 496 dat->tls_aad_len = aad_len; 497 498 len = buf[aad_len - 2] << 8 | buf[aad_len - 1]; 499 /* Correct length for explicit iv. */ 500 if (len < EVP_GCM_TLS_EXPLICIT_IV_LEN) 501 return 0; 502 len -= EVP_GCM_TLS_EXPLICIT_IV_LEN; 503 504 /* If decrypting correct for tag too. */ 505 if (!dat->enc) { 506 if (len < EVP_GCM_TLS_TAG_LEN) 507 return 0; 508 len -= EVP_GCM_TLS_TAG_LEN; 509 } 510 buf[aad_len - 2] = (unsigned char)(len >> 8); 511 buf[aad_len - 1] = (unsigned char)(len & 0xff); 512 /* Extra padding: tag appended to record. */ 513 return EVP_GCM_TLS_TAG_LEN; 514 } 515 516 static int gcm_tls_iv_set_fixed(PROV_GCM_CTX *ctx, unsigned char *iv, 517 size_t len) 518 { 519 /* Special case: -1 length restores whole IV */ 520 if (len == (size_t)-1) { 521 memcpy(ctx->iv, iv, ctx->ivlen); 522 ctx->iv_gen_rand = 0; 523 ctx->iv_gen = 1; 524 ctx->iv_state = IV_STATE_BUFFERED; 525 return 1; 526 } 527 /* Fixed field must be at least 4 bytes and invocation field at least 8 */ 528 if ((len < EVP_GCM_TLS_FIXED_IV_LEN) 529 || (ctx->ivlen - (int)len) < EVP_GCM_TLS_EXPLICIT_IV_LEN) 530 return 0; 531 if (len > 0) 532 memcpy(ctx->iv, iv, len); 533 if (ctx->enc) { 534 if (RAND_bytes_ex(ctx->libctx, ctx->iv + len, ctx->ivlen - len, 0) <= 0) 535 return 0; 536 ctx->iv_gen_rand = 1; 537 } 538 ctx->iv_gen = 1; 539 ctx->iv_state = IV_STATE_BUFFERED; 540 return 1; 541 } 542 543 /* 544 * Handle TLS GCM packet format. This consists of the last portion of the IV 545 * followed by the payload and finally the tag. On encrypt generate IV, 546 * encrypt payload and write the tag. On verify retrieve IV, decrypt payload 547 * and verify tag. 548 */ 549 static int gcm_tls_cipher(PROV_GCM_CTX *ctx, unsigned char *out, size_t *padlen, 550 const unsigned char *in, size_t len) 551 { 552 int rv = 0; 553 size_t arg = EVP_GCM_TLS_EXPLICIT_IV_LEN; 554 size_t plen = 0; 555 unsigned char *tag = NULL; 556 557 if (!ossl_prov_is_running() || !ctx->key_set) 558 goto err; 559 560 /* Encrypt/decrypt must be performed in place */ 561 if (out != in || len < (EVP_GCM_TLS_EXPLICIT_IV_LEN + EVP_GCM_TLS_TAG_LEN)) 562 goto err; 563 564 /* 565 * Check for too many keys as per FIPS 140-2 IG A.5 "Key/IV Pair Uniqueness 566 * Requirements from SP 800-38D". The requirements is for one party to the 567 * communication to fail after 2^64 - 1 keys. We do this on the encrypting 568 * side only. 569 */ 570 if (ctx->enc && ++ctx->tls_enc_records == 0) { 571 ERR_raise(ERR_LIB_PROV, PROV_R_TOO_MANY_RECORDS); 572 goto err; 573 } 574 575 /* 576 * Set IV from start of buffer or generate IV and write to start of 577 * buffer. 578 */ 579 if (ctx->enc) { 580 if (!getivgen(ctx, out, arg)) 581 goto err; 582 } else { 583 if (!setivinv(ctx, out, arg)) 584 goto err; 585 } 586 587 /* Fix buffer and length to point to payload */ 588 in += EVP_GCM_TLS_EXPLICIT_IV_LEN; 589 out += EVP_GCM_TLS_EXPLICIT_IV_LEN; 590 len -= EVP_GCM_TLS_EXPLICIT_IV_LEN + EVP_GCM_TLS_TAG_LEN; 591 592 tag = ctx->enc ? out + len : (unsigned char *)in + len; 593 if (!ctx->hw->oneshot(ctx, ctx->buf, ctx->tls_aad_len, in, len, out, tag, 594 EVP_GCM_TLS_TAG_LEN)) { 595 if (!ctx->enc) 596 OPENSSL_cleanse(out, len); 597 goto err; 598 } 599 if (ctx->enc) 600 plen = len + EVP_GCM_TLS_EXPLICIT_IV_LEN + EVP_GCM_TLS_TAG_LEN; 601 else 602 plen = len; 603 604 rv = 1; 605 err: 606 ctx->iv_state = IV_STATE_FINISHED; 607 ctx->tls_aad_len = UNINITIALISED_SIZET; 608 *padlen = plen; 609 return rv; 610 } 611