1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 2004 IBM Corporation 4 * Copyright (C) 2014 Intel Corporation 5 */ 6 7 #include <linux/asn1_encoder.h> 8 #include <linux/oid_registry.h> 9 #include <linux/string.h> 10 #include <linux/err.h> 11 #include <linux/tpm.h> 12 #include <linux/tpm_command.h> 13 14 #include <keys/trusted-type.h> 15 #include <keys/trusted_tpm.h> 16 17 #include <asm/unaligned.h> 18 19 #include "tpm2key.asn1.h" 20 21 static struct tpm2_hash tpm2_hash_map[] = { 22 {HASH_ALGO_SHA1, TPM_ALG_SHA1}, 23 {HASH_ALGO_SHA256, TPM_ALG_SHA256}, 24 {HASH_ALGO_SHA384, TPM_ALG_SHA384}, 25 {HASH_ALGO_SHA512, TPM_ALG_SHA512}, 26 {HASH_ALGO_SM3_256, TPM_ALG_SM3_256}, 27 }; 28 29 static u32 tpm2key_oid[] = { 2, 23, 133, 10, 1, 5 }; 30 31 static int tpm2_key_encode(struct trusted_key_payload *payload, 32 struct trusted_key_options *options, 33 u8 *src, u32 len) 34 { 35 const int SCRATCH_SIZE = PAGE_SIZE; 36 u8 *scratch = kmalloc(SCRATCH_SIZE, GFP_KERNEL); 37 u8 *work = scratch, *work1; 38 u8 *end_work = scratch + SCRATCH_SIZE; 39 u8 *priv, *pub; 40 u16 priv_len, pub_len; 41 42 priv_len = get_unaligned_be16(src) + 2; 43 priv = src; 44 45 src += priv_len; 46 47 pub_len = get_unaligned_be16(src) + 2; 48 pub = src; 49 50 if (!scratch) 51 return -ENOMEM; 52 53 work = asn1_encode_oid(work, end_work, tpm2key_oid, 54 asn1_oid_len(tpm2key_oid)); 55 56 if (options->blobauth_len == 0) { 57 unsigned char bool[3], *w = bool; 58 /* tag 0 is emptyAuth */ 59 w = asn1_encode_boolean(w, w + sizeof(bool), true); 60 if (WARN(IS_ERR(w), "BUG: Boolean failed to encode")) 61 return PTR_ERR(w); 62 work = asn1_encode_tag(work, end_work, 0, bool, w - bool); 63 } 64 65 /* 66 * Assume both octet strings will encode to a 2 byte definite length 67 * 68 * Note: For a well behaved TPM, this warning should never 69 * trigger, so if it does there's something nefarious going on 70 */ 71 if (WARN(work - scratch + pub_len + priv_len + 14 > SCRATCH_SIZE, 72 "BUG: scratch buffer is too small")) 73 return -EINVAL; 74 75 work = asn1_encode_integer(work, end_work, options->keyhandle); 76 work = asn1_encode_octet_string(work, end_work, pub, pub_len); 77 work = asn1_encode_octet_string(work, end_work, priv, priv_len); 78 79 work1 = payload->blob; 80 work1 = asn1_encode_sequence(work1, work1 + sizeof(payload->blob), 81 scratch, work - scratch); 82 if (WARN(IS_ERR(work1), "BUG: ASN.1 encoder failed")) 83 return PTR_ERR(work1); 84 85 return work1 - payload->blob; 86 } 87 88 struct tpm2_key_context { 89 u32 parent; 90 const u8 *pub; 91 u32 pub_len; 92 const u8 *priv; 93 u32 priv_len; 94 }; 95 96 static int tpm2_key_decode(struct trusted_key_payload *payload, 97 struct trusted_key_options *options, 98 u8 **buf) 99 { 100 int ret; 101 struct tpm2_key_context ctx; 102 u8 *blob; 103 104 memset(&ctx, 0, sizeof(ctx)); 105 106 ret = asn1_ber_decoder(&tpm2key_decoder, &ctx, payload->blob, 107 payload->blob_len); 108 if (ret < 0) 109 return ret; 110 111 if (ctx.priv_len + ctx.pub_len > MAX_BLOB_SIZE) 112 return -EINVAL; 113 114 blob = kmalloc(ctx.priv_len + ctx.pub_len + 4, GFP_KERNEL); 115 if (!blob) 116 return -ENOMEM; 117 118 *buf = blob; 119 options->keyhandle = ctx.parent; 120 121 memcpy(blob, ctx.priv, ctx.priv_len); 122 blob += ctx.priv_len; 123 124 memcpy(blob, ctx.pub, ctx.pub_len); 125 126 return 0; 127 } 128 129 int tpm2_key_parent(void *context, size_t hdrlen, 130 unsigned char tag, 131 const void *value, size_t vlen) 132 { 133 struct tpm2_key_context *ctx = context; 134 const u8 *v = value; 135 int i; 136 137 ctx->parent = 0; 138 for (i = 0; i < vlen; i++) { 139 ctx->parent <<= 8; 140 ctx->parent |= v[i]; 141 } 142 143 return 0; 144 } 145 146 int tpm2_key_type(void *context, size_t hdrlen, 147 unsigned char tag, 148 const void *value, size_t vlen) 149 { 150 enum OID oid = look_up_OID(value, vlen); 151 152 if (oid != OID_TPMSealedData) { 153 char buffer[50]; 154 155 sprint_oid(value, vlen, buffer, sizeof(buffer)); 156 pr_debug("OID is \"%s\" which is not TPMSealedData\n", 157 buffer); 158 return -EINVAL; 159 } 160 161 return 0; 162 } 163 164 int tpm2_key_pub(void *context, size_t hdrlen, 165 unsigned char tag, 166 const void *value, size_t vlen) 167 { 168 struct tpm2_key_context *ctx = context; 169 170 ctx->pub = value; 171 ctx->pub_len = vlen; 172 173 return 0; 174 } 175 176 int tpm2_key_priv(void *context, size_t hdrlen, 177 unsigned char tag, 178 const void *value, size_t vlen) 179 { 180 struct tpm2_key_context *ctx = context; 181 182 ctx->priv = value; 183 ctx->priv_len = vlen; 184 185 return 0; 186 } 187 188 /** 189 * tpm_buf_append_auth() - append TPMS_AUTH_COMMAND to the buffer. 190 * 191 * @buf: an allocated tpm_buf instance 192 * @session_handle: session handle 193 * @nonce: the session nonce, may be NULL if not used 194 * @nonce_len: the session nonce length, may be 0 if not used 195 * @attributes: the session attributes 196 * @hmac: the session HMAC or password, may be NULL if not used 197 * @hmac_len: the session HMAC or password length, maybe 0 if not used 198 */ 199 static void tpm2_buf_append_auth(struct tpm_buf *buf, u32 session_handle, 200 const u8 *nonce, u16 nonce_len, 201 u8 attributes, 202 const u8 *hmac, u16 hmac_len) 203 { 204 tpm_buf_append_u32(buf, 9 + nonce_len + hmac_len); 205 tpm_buf_append_u32(buf, session_handle); 206 tpm_buf_append_u16(buf, nonce_len); 207 208 if (nonce && nonce_len) 209 tpm_buf_append(buf, nonce, nonce_len); 210 211 tpm_buf_append_u8(buf, attributes); 212 tpm_buf_append_u16(buf, hmac_len); 213 214 if (hmac && hmac_len) 215 tpm_buf_append(buf, hmac, hmac_len); 216 } 217 218 /** 219 * tpm2_seal_trusted() - seal the payload of a trusted key 220 * 221 * @chip: TPM chip to use 222 * @payload: the key data in clear and encrypted form 223 * @options: authentication values and other options 224 * 225 * Return: < 0 on error and 0 on success. 226 */ 227 int tpm2_seal_trusted(struct tpm_chip *chip, 228 struct trusted_key_payload *payload, 229 struct trusted_key_options *options) 230 { 231 int blob_len = 0; 232 struct tpm_buf buf; 233 u32 hash; 234 u32 flags; 235 int i; 236 int rc; 237 238 for (i = 0; i < ARRAY_SIZE(tpm2_hash_map); i++) { 239 if (options->hash == tpm2_hash_map[i].crypto_id) { 240 hash = tpm2_hash_map[i].tpm_id; 241 break; 242 } 243 } 244 245 if (i == ARRAY_SIZE(tpm2_hash_map)) 246 return -EINVAL; 247 248 if (!options->keyhandle) 249 return -EINVAL; 250 251 rc = tpm_try_get_ops(chip); 252 if (rc) 253 return rc; 254 255 rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_CREATE); 256 if (rc) { 257 tpm_put_ops(chip); 258 return rc; 259 } 260 261 tpm_buf_append_u32(&buf, options->keyhandle); 262 tpm2_buf_append_auth(&buf, TPM2_RS_PW, 263 NULL /* nonce */, 0, 264 0 /* session_attributes */, 265 options->keyauth /* hmac */, 266 TPM_DIGEST_SIZE); 267 268 /* sensitive */ 269 tpm_buf_append_u16(&buf, 4 + options->blobauth_len + payload->key_len); 270 271 tpm_buf_append_u16(&buf, options->blobauth_len); 272 if (options->blobauth_len) 273 tpm_buf_append(&buf, options->blobauth, options->blobauth_len); 274 275 tpm_buf_append_u16(&buf, payload->key_len); 276 tpm_buf_append(&buf, payload->key, payload->key_len); 277 278 /* public */ 279 tpm_buf_append_u16(&buf, 14 + options->policydigest_len); 280 tpm_buf_append_u16(&buf, TPM_ALG_KEYEDHASH); 281 tpm_buf_append_u16(&buf, hash); 282 283 /* key properties */ 284 flags = 0; 285 flags |= options->policydigest_len ? 0 : TPM2_OA_USER_WITH_AUTH; 286 flags |= payload->migratable ? (TPM2_OA_FIXED_TPM | 287 TPM2_OA_FIXED_PARENT) : 0; 288 tpm_buf_append_u32(&buf, flags); 289 290 /* policy */ 291 tpm_buf_append_u16(&buf, options->policydigest_len); 292 if (options->policydigest_len) 293 tpm_buf_append(&buf, options->policydigest, 294 options->policydigest_len); 295 296 /* public parameters */ 297 tpm_buf_append_u16(&buf, TPM_ALG_NULL); 298 tpm_buf_append_u16(&buf, 0); 299 300 /* outside info */ 301 tpm_buf_append_u16(&buf, 0); 302 303 /* creation PCR */ 304 tpm_buf_append_u32(&buf, 0); 305 306 if (buf.flags & TPM_BUF_OVERFLOW) { 307 rc = -E2BIG; 308 goto out; 309 } 310 311 rc = tpm_transmit_cmd(chip, &buf, 4, "sealing data"); 312 if (rc) 313 goto out; 314 315 blob_len = be32_to_cpup((__be32 *) &buf.data[TPM_HEADER_SIZE]); 316 if (blob_len > MAX_BLOB_SIZE) { 317 rc = -E2BIG; 318 goto out; 319 } 320 if (tpm_buf_length(&buf) < TPM_HEADER_SIZE + 4 + blob_len) { 321 rc = -EFAULT; 322 goto out; 323 } 324 325 blob_len = tpm2_key_encode(payload, options, 326 &buf.data[TPM_HEADER_SIZE + 4], 327 blob_len); 328 329 out: 330 tpm_buf_destroy(&buf); 331 332 if (rc > 0) { 333 if (tpm2_rc_value(rc) == TPM2_RC_HASH) 334 rc = -EINVAL; 335 else 336 rc = -EPERM; 337 } 338 if (blob_len < 0) 339 rc = blob_len; 340 else 341 payload->blob_len = blob_len; 342 343 tpm_put_ops(chip); 344 return rc; 345 } 346 347 /** 348 * tpm2_load_cmd() - execute a TPM2_Load command 349 * 350 * @chip: TPM chip to use 351 * @payload: the key data in clear and encrypted form 352 * @options: authentication values and other options 353 * @blob_handle: returned blob handle 354 * 355 * Return: 0 on success. 356 * -E2BIG on wrong payload size. 357 * -EPERM on tpm error status. 358 * < 0 error from tpm_send. 359 */ 360 static int tpm2_load_cmd(struct tpm_chip *chip, 361 struct trusted_key_payload *payload, 362 struct trusted_key_options *options, 363 u32 *blob_handle) 364 { 365 struct tpm_buf buf; 366 unsigned int private_len; 367 unsigned int public_len; 368 unsigned int blob_len; 369 u8 *blob, *pub; 370 int rc; 371 u32 attrs; 372 373 rc = tpm2_key_decode(payload, options, &blob); 374 if (rc) { 375 /* old form */ 376 blob = payload->blob; 377 payload->old_format = 1; 378 } 379 380 /* new format carries keyhandle but old format doesn't */ 381 if (!options->keyhandle) 382 return -EINVAL; 383 384 /* must be big enough for at least the two be16 size counts */ 385 if (payload->blob_len < 4) 386 return -EINVAL; 387 388 private_len = get_unaligned_be16(blob); 389 390 /* must be big enough for following public_len */ 391 if (private_len + 2 + 2 > (payload->blob_len)) 392 return -E2BIG; 393 394 public_len = get_unaligned_be16(blob + 2 + private_len); 395 if (private_len + 2 + public_len + 2 > payload->blob_len) 396 return -E2BIG; 397 398 pub = blob + 2 + private_len + 2; 399 /* key attributes are always at offset 4 */ 400 attrs = get_unaligned_be32(pub + 4); 401 402 if ((attrs & (TPM2_OA_FIXED_TPM | TPM2_OA_FIXED_PARENT)) == 403 (TPM2_OA_FIXED_TPM | TPM2_OA_FIXED_PARENT)) 404 payload->migratable = 0; 405 else 406 payload->migratable = 1; 407 408 blob_len = private_len + public_len + 4; 409 if (blob_len > payload->blob_len) 410 return -E2BIG; 411 412 rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_LOAD); 413 if (rc) 414 return rc; 415 416 tpm_buf_append_u32(&buf, options->keyhandle); 417 tpm2_buf_append_auth(&buf, TPM2_RS_PW, 418 NULL /* nonce */, 0, 419 0 /* session_attributes */, 420 options->keyauth /* hmac */, 421 TPM_DIGEST_SIZE); 422 423 tpm_buf_append(&buf, blob, blob_len); 424 425 if (buf.flags & TPM_BUF_OVERFLOW) { 426 rc = -E2BIG; 427 goto out; 428 } 429 430 rc = tpm_transmit_cmd(chip, &buf, 4, "loading blob"); 431 if (!rc) 432 *blob_handle = be32_to_cpup( 433 (__be32 *) &buf.data[TPM_HEADER_SIZE]); 434 435 out: 436 if (blob != payload->blob) 437 kfree(blob); 438 tpm_buf_destroy(&buf); 439 440 if (rc > 0) 441 rc = -EPERM; 442 443 return rc; 444 } 445 446 /** 447 * tpm2_unseal_cmd() - execute a TPM2_Unload command 448 * 449 * @chip: TPM chip to use 450 * @payload: the key data in clear and encrypted form 451 * @options: authentication values and other options 452 * @blob_handle: blob handle 453 * 454 * Return: 0 on success 455 * -EPERM on tpm error status 456 * < 0 error from tpm_send 457 */ 458 static int tpm2_unseal_cmd(struct tpm_chip *chip, 459 struct trusted_key_payload *payload, 460 struct trusted_key_options *options, 461 u32 blob_handle) 462 { 463 struct tpm_buf buf; 464 u16 data_len; 465 u8 *data; 466 int rc; 467 468 rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_UNSEAL); 469 if (rc) 470 return rc; 471 472 tpm_buf_append_u32(&buf, blob_handle); 473 tpm2_buf_append_auth(&buf, 474 options->policyhandle ? 475 options->policyhandle : TPM2_RS_PW, 476 NULL /* nonce */, 0, 477 TPM2_SA_CONTINUE_SESSION, 478 options->blobauth /* hmac */, 479 options->blobauth_len); 480 481 rc = tpm_transmit_cmd(chip, &buf, 6, "unsealing"); 482 if (rc > 0) 483 rc = -EPERM; 484 485 if (!rc) { 486 data_len = be16_to_cpup( 487 (__be16 *) &buf.data[TPM_HEADER_SIZE + 4]); 488 if (data_len < MIN_KEY_SIZE || data_len > MAX_KEY_SIZE) { 489 rc = -EFAULT; 490 goto out; 491 } 492 493 if (tpm_buf_length(&buf) < TPM_HEADER_SIZE + 6 + data_len) { 494 rc = -EFAULT; 495 goto out; 496 } 497 data = &buf.data[TPM_HEADER_SIZE + 6]; 498 499 if (payload->old_format) { 500 /* migratable flag is at the end of the key */ 501 memcpy(payload->key, data, data_len - 1); 502 payload->key_len = data_len - 1; 503 payload->migratable = data[data_len - 1]; 504 } else { 505 /* 506 * migratable flag already collected from key 507 * attributes 508 */ 509 memcpy(payload->key, data, data_len); 510 payload->key_len = data_len; 511 } 512 } 513 514 out: 515 tpm_buf_destroy(&buf); 516 return rc; 517 } 518 519 /** 520 * tpm2_unseal_trusted() - unseal the payload of a trusted key 521 * 522 * @chip: TPM chip to use 523 * @payload: the key data in clear and encrypted form 524 * @options: authentication values and other options 525 * 526 * Return: Same as with tpm_send. 527 */ 528 int tpm2_unseal_trusted(struct tpm_chip *chip, 529 struct trusted_key_payload *payload, 530 struct trusted_key_options *options) 531 { 532 u32 blob_handle; 533 int rc; 534 535 rc = tpm_try_get_ops(chip); 536 if (rc) 537 return rc; 538 539 rc = tpm2_load_cmd(chip, payload, options, &blob_handle); 540 if (rc) 541 goto out; 542 543 rc = tpm2_unseal_cmd(chip, payload, options, blob_handle); 544 tpm2_flush_context(chip, blob_handle); 545 546 out: 547 tpm_put_ops(chip); 548 549 return rc; 550 } 551