1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 2005,2006,2007,2008 IBM Corporation 4 * 5 * Authors: 6 * Mimi Zohar <zohar@us.ibm.com> 7 * Kylene Hall <kjhall@us.ibm.com> 8 * 9 * File: ima_crypto.c 10 * Calculates md5/sha1 file hash, template hash, boot-aggreate hash 11 */ 12 13 #include <linux/kernel.h> 14 #include <linux/moduleparam.h> 15 #include <linux/ratelimit.h> 16 #include <linux/file.h> 17 #include <linux/crypto.h> 18 #include <linux/scatterlist.h> 19 #include <linux/err.h> 20 #include <linux/slab.h> 21 #include <crypto/hash.h> 22 23 #include "ima.h" 24 25 /* minimum file size for ahash use */ 26 static unsigned long ima_ahash_minsize; 27 module_param_named(ahash_minsize, ima_ahash_minsize, ulong, 0644); 28 MODULE_PARM_DESC(ahash_minsize, "Minimum file size for ahash use"); 29 30 /* default is 0 - 1 page. */ 31 static int ima_maxorder; 32 static unsigned int ima_bufsize = PAGE_SIZE; 33 34 static int param_set_bufsize(const char *val, const struct kernel_param *kp) 35 { 36 unsigned long long size; 37 int order; 38 39 size = memparse(val, NULL); 40 order = get_order(size); 41 if (order > MAX_ORDER) 42 return -EINVAL; 43 ima_maxorder = order; 44 ima_bufsize = PAGE_SIZE << order; 45 return 0; 46 } 47 48 static const struct kernel_param_ops param_ops_bufsize = { 49 .set = param_set_bufsize, 50 .get = param_get_uint, 51 }; 52 #define param_check_bufsize(name, p) __param_check(name, p, unsigned int) 53 54 module_param_named(ahash_bufsize, ima_bufsize, bufsize, 0644); 55 MODULE_PARM_DESC(ahash_bufsize, "Maximum ahash buffer size"); 56 57 static struct crypto_shash *ima_shash_tfm; 58 static struct crypto_ahash *ima_ahash_tfm; 59 60 struct ima_algo_desc { 61 struct crypto_shash *tfm; 62 enum hash_algo algo; 63 }; 64 65 int ima_sha1_idx __ro_after_init; 66 int ima_hash_algo_idx __ro_after_init; 67 /* 68 * Additional number of slots reserved, as needed, for SHA1 69 * and IMA default algo. 70 */ 71 int ima_extra_slots __ro_after_init; 72 73 static struct ima_algo_desc *ima_algo_array; 74 75 static int __init ima_init_ima_crypto(void) 76 { 77 long rc; 78 79 ima_shash_tfm = crypto_alloc_shash(hash_algo_name[ima_hash_algo], 0, 0); 80 if (IS_ERR(ima_shash_tfm)) { 81 rc = PTR_ERR(ima_shash_tfm); 82 pr_err("Can not allocate %s (reason: %ld)\n", 83 hash_algo_name[ima_hash_algo], rc); 84 return rc; 85 } 86 pr_info("Allocated hash algorithm: %s\n", 87 hash_algo_name[ima_hash_algo]); 88 return 0; 89 } 90 91 static struct crypto_shash *ima_alloc_tfm(enum hash_algo algo) 92 { 93 struct crypto_shash *tfm = ima_shash_tfm; 94 int rc, i; 95 96 if (algo < 0 || algo >= HASH_ALGO__LAST) 97 algo = ima_hash_algo; 98 99 if (algo == ima_hash_algo) 100 return tfm; 101 102 for (i = 0; i < NR_BANKS(ima_tpm_chip) + ima_extra_slots; i++) 103 if (ima_algo_array[i].tfm && ima_algo_array[i].algo == algo) 104 return ima_algo_array[i].tfm; 105 106 tfm = crypto_alloc_shash(hash_algo_name[algo], 0, 0); 107 if (IS_ERR(tfm)) { 108 rc = PTR_ERR(tfm); 109 pr_err("Can not allocate %s (reason: %d)\n", 110 hash_algo_name[algo], rc); 111 } 112 return tfm; 113 } 114 115 int __init ima_init_crypto(void) 116 { 117 enum hash_algo algo; 118 long rc; 119 int i; 120 121 rc = ima_init_ima_crypto(); 122 if (rc) 123 return rc; 124 125 ima_sha1_idx = -1; 126 ima_hash_algo_idx = -1; 127 128 for (i = 0; i < NR_BANKS(ima_tpm_chip); i++) { 129 algo = ima_tpm_chip->allocated_banks[i].crypto_id; 130 if (algo == HASH_ALGO_SHA1) 131 ima_sha1_idx = i; 132 133 if (algo == ima_hash_algo) 134 ima_hash_algo_idx = i; 135 } 136 137 if (ima_sha1_idx < 0) { 138 ima_sha1_idx = NR_BANKS(ima_tpm_chip) + ima_extra_slots++; 139 if (ima_hash_algo == HASH_ALGO_SHA1) 140 ima_hash_algo_idx = ima_sha1_idx; 141 } 142 143 if (ima_hash_algo_idx < 0) 144 ima_hash_algo_idx = NR_BANKS(ima_tpm_chip) + ima_extra_slots++; 145 146 ima_algo_array = kcalloc(NR_BANKS(ima_tpm_chip) + ima_extra_slots, 147 sizeof(*ima_algo_array), GFP_KERNEL); 148 if (!ima_algo_array) { 149 rc = -ENOMEM; 150 goto out; 151 } 152 153 for (i = 0; i < NR_BANKS(ima_tpm_chip); i++) { 154 algo = ima_tpm_chip->allocated_banks[i].crypto_id; 155 ima_algo_array[i].algo = algo; 156 157 /* unknown TPM algorithm */ 158 if (algo == HASH_ALGO__LAST) 159 continue; 160 161 if (algo == ima_hash_algo) { 162 ima_algo_array[i].tfm = ima_shash_tfm; 163 continue; 164 } 165 166 ima_algo_array[i].tfm = ima_alloc_tfm(algo); 167 if (IS_ERR(ima_algo_array[i].tfm)) { 168 if (algo == HASH_ALGO_SHA1) { 169 rc = PTR_ERR(ima_algo_array[i].tfm); 170 ima_algo_array[i].tfm = NULL; 171 goto out_array; 172 } 173 174 ima_algo_array[i].tfm = NULL; 175 } 176 } 177 178 if (ima_sha1_idx >= NR_BANKS(ima_tpm_chip)) { 179 if (ima_hash_algo == HASH_ALGO_SHA1) { 180 ima_algo_array[ima_sha1_idx].tfm = ima_shash_tfm; 181 } else { 182 ima_algo_array[ima_sha1_idx].tfm = 183 ima_alloc_tfm(HASH_ALGO_SHA1); 184 if (IS_ERR(ima_algo_array[ima_sha1_idx].tfm)) { 185 rc = PTR_ERR(ima_algo_array[ima_sha1_idx].tfm); 186 goto out_array; 187 } 188 } 189 190 ima_algo_array[ima_sha1_idx].algo = HASH_ALGO_SHA1; 191 } 192 193 if (ima_hash_algo_idx >= NR_BANKS(ima_tpm_chip) && 194 ima_hash_algo_idx != ima_sha1_idx) { 195 ima_algo_array[ima_hash_algo_idx].tfm = ima_shash_tfm; 196 ima_algo_array[ima_hash_algo_idx].algo = ima_hash_algo; 197 } 198 199 return 0; 200 out_array: 201 for (i = 0; i < NR_BANKS(ima_tpm_chip) + ima_extra_slots; i++) { 202 if (!ima_algo_array[i].tfm || 203 ima_algo_array[i].tfm == ima_shash_tfm) 204 continue; 205 206 crypto_free_shash(ima_algo_array[i].tfm); 207 } 208 kfree(ima_algo_array); 209 out: 210 crypto_free_shash(ima_shash_tfm); 211 return rc; 212 } 213 214 static void ima_free_tfm(struct crypto_shash *tfm) 215 { 216 int i; 217 218 if (tfm == ima_shash_tfm) 219 return; 220 221 for (i = 0; i < NR_BANKS(ima_tpm_chip) + ima_extra_slots; i++) 222 if (ima_algo_array[i].tfm == tfm) 223 return; 224 225 crypto_free_shash(tfm); 226 } 227 228 /** 229 * ima_alloc_pages() - Allocate contiguous pages. 230 * @max_size: Maximum amount of memory to allocate. 231 * @allocated_size: Returned size of actual allocation. 232 * @last_warn: Should the min_size allocation warn or not. 233 * 234 * Tries to do opportunistic allocation for memory first trying to allocate 235 * max_size amount of memory and then splitting that until zero order is 236 * reached. Allocation is tried without generating allocation warnings unless 237 * last_warn is set. Last_warn set affects only last allocation of zero order. 238 * 239 * By default, ima_maxorder is 0 and it is equivalent to kmalloc(GFP_KERNEL) 240 * 241 * Return pointer to allocated memory, or NULL on failure. 242 */ 243 static void *ima_alloc_pages(loff_t max_size, size_t *allocated_size, 244 int last_warn) 245 { 246 void *ptr; 247 int order = ima_maxorder; 248 gfp_t gfp_mask = __GFP_RECLAIM | __GFP_NOWARN | __GFP_NORETRY; 249 250 if (order) 251 order = min(get_order(max_size), order); 252 253 for (; order; order--) { 254 ptr = (void *)__get_free_pages(gfp_mask, order); 255 if (ptr) { 256 *allocated_size = PAGE_SIZE << order; 257 return ptr; 258 } 259 } 260 261 /* order is zero - one page */ 262 263 gfp_mask = GFP_KERNEL; 264 265 if (!last_warn) 266 gfp_mask |= __GFP_NOWARN; 267 268 ptr = (void *)__get_free_pages(gfp_mask, 0); 269 if (ptr) { 270 *allocated_size = PAGE_SIZE; 271 return ptr; 272 } 273 274 *allocated_size = 0; 275 return NULL; 276 } 277 278 /** 279 * ima_free_pages() - Free pages allocated by ima_alloc_pages(). 280 * @ptr: Pointer to allocated pages. 281 * @size: Size of allocated buffer. 282 */ 283 static void ima_free_pages(void *ptr, size_t size) 284 { 285 if (!ptr) 286 return; 287 free_pages((unsigned long)ptr, get_order(size)); 288 } 289 290 static struct crypto_ahash *ima_alloc_atfm(enum hash_algo algo) 291 { 292 struct crypto_ahash *tfm = ima_ahash_tfm; 293 int rc; 294 295 if (algo < 0 || algo >= HASH_ALGO__LAST) 296 algo = ima_hash_algo; 297 298 if (algo != ima_hash_algo || !tfm) { 299 tfm = crypto_alloc_ahash(hash_algo_name[algo], 0, 0); 300 if (!IS_ERR(tfm)) { 301 if (algo == ima_hash_algo) 302 ima_ahash_tfm = tfm; 303 } else { 304 rc = PTR_ERR(tfm); 305 pr_err("Can not allocate %s (reason: %d)\n", 306 hash_algo_name[algo], rc); 307 } 308 } 309 return tfm; 310 } 311 312 static void ima_free_atfm(struct crypto_ahash *tfm) 313 { 314 if (tfm != ima_ahash_tfm) 315 crypto_free_ahash(tfm); 316 } 317 318 static inline int ahash_wait(int err, struct crypto_wait *wait) 319 { 320 321 err = crypto_wait_req(err, wait); 322 323 if (err) 324 pr_crit_ratelimited("ahash calculation failed: err: %d\n", err); 325 326 return err; 327 } 328 329 static int ima_calc_file_hash_atfm(struct file *file, 330 struct ima_digest_data *hash, 331 struct crypto_ahash *tfm) 332 { 333 loff_t i_size, offset; 334 char *rbuf[2] = { NULL, }; 335 int rc, rbuf_len, active = 0, ahash_rc = 0; 336 struct ahash_request *req; 337 struct scatterlist sg[1]; 338 struct crypto_wait wait; 339 size_t rbuf_size[2]; 340 341 hash->length = crypto_ahash_digestsize(tfm); 342 343 req = ahash_request_alloc(tfm, GFP_KERNEL); 344 if (!req) 345 return -ENOMEM; 346 347 crypto_init_wait(&wait); 348 ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG | 349 CRYPTO_TFM_REQ_MAY_SLEEP, 350 crypto_req_done, &wait); 351 352 rc = ahash_wait(crypto_ahash_init(req), &wait); 353 if (rc) 354 goto out1; 355 356 i_size = i_size_read(file_inode(file)); 357 358 if (i_size == 0) 359 goto out2; 360 361 /* 362 * Try to allocate maximum size of memory. 363 * Fail if even a single page cannot be allocated. 364 */ 365 rbuf[0] = ima_alloc_pages(i_size, &rbuf_size[0], 1); 366 if (!rbuf[0]) { 367 rc = -ENOMEM; 368 goto out1; 369 } 370 371 /* Only allocate one buffer if that is enough. */ 372 if (i_size > rbuf_size[0]) { 373 /* 374 * Try to allocate secondary buffer. If that fails fallback to 375 * using single buffering. Use previous memory allocation size 376 * as baseline for possible allocation size. 377 */ 378 rbuf[1] = ima_alloc_pages(i_size - rbuf_size[0], 379 &rbuf_size[1], 0); 380 } 381 382 for (offset = 0; offset < i_size; offset += rbuf_len) { 383 if (!rbuf[1] && offset) { 384 /* Not using two buffers, and it is not the first 385 * read/request, wait for the completion of the 386 * previous ahash_update() request. 387 */ 388 rc = ahash_wait(ahash_rc, &wait); 389 if (rc) 390 goto out3; 391 } 392 /* read buffer */ 393 rbuf_len = min_t(loff_t, i_size - offset, rbuf_size[active]); 394 rc = integrity_kernel_read(file, offset, rbuf[active], 395 rbuf_len); 396 if (rc != rbuf_len) { 397 if (rc >= 0) 398 rc = -EINVAL; 399 /* 400 * Forward current rc, do not overwrite with return value 401 * from ahash_wait() 402 */ 403 ahash_wait(ahash_rc, &wait); 404 goto out3; 405 } 406 407 if (rbuf[1] && offset) { 408 /* Using two buffers, and it is not the first 409 * read/request, wait for the completion of the 410 * previous ahash_update() request. 411 */ 412 rc = ahash_wait(ahash_rc, &wait); 413 if (rc) 414 goto out3; 415 } 416 417 sg_init_one(&sg[0], rbuf[active], rbuf_len); 418 ahash_request_set_crypt(req, sg, NULL, rbuf_len); 419 420 ahash_rc = crypto_ahash_update(req); 421 422 if (rbuf[1]) 423 active = !active; /* swap buffers, if we use two */ 424 } 425 /* wait for the last update request to complete */ 426 rc = ahash_wait(ahash_rc, &wait); 427 out3: 428 ima_free_pages(rbuf[0], rbuf_size[0]); 429 ima_free_pages(rbuf[1], rbuf_size[1]); 430 out2: 431 if (!rc) { 432 ahash_request_set_crypt(req, NULL, hash->digest, 0); 433 rc = ahash_wait(crypto_ahash_final(req), &wait); 434 } 435 out1: 436 ahash_request_free(req); 437 return rc; 438 } 439 440 static int ima_calc_file_ahash(struct file *file, struct ima_digest_data *hash) 441 { 442 struct crypto_ahash *tfm; 443 int rc; 444 445 tfm = ima_alloc_atfm(hash->algo); 446 if (IS_ERR(tfm)) 447 return PTR_ERR(tfm); 448 449 rc = ima_calc_file_hash_atfm(file, hash, tfm); 450 451 ima_free_atfm(tfm); 452 453 return rc; 454 } 455 456 static int ima_calc_file_hash_tfm(struct file *file, 457 struct ima_digest_data *hash, 458 struct crypto_shash *tfm) 459 { 460 loff_t i_size, offset = 0; 461 char *rbuf; 462 int rc; 463 SHASH_DESC_ON_STACK(shash, tfm); 464 465 shash->tfm = tfm; 466 467 hash->length = crypto_shash_digestsize(tfm); 468 469 rc = crypto_shash_init(shash); 470 if (rc != 0) 471 return rc; 472 473 i_size = i_size_read(file_inode(file)); 474 475 if (i_size == 0) 476 goto out; 477 478 rbuf = kzalloc(PAGE_SIZE, GFP_KERNEL); 479 if (!rbuf) 480 return -ENOMEM; 481 482 while (offset < i_size) { 483 int rbuf_len; 484 485 rbuf_len = integrity_kernel_read(file, offset, rbuf, PAGE_SIZE); 486 if (rbuf_len < 0) { 487 rc = rbuf_len; 488 break; 489 } 490 if (rbuf_len == 0) { /* unexpected EOF */ 491 rc = -EINVAL; 492 break; 493 } 494 offset += rbuf_len; 495 496 rc = crypto_shash_update(shash, rbuf, rbuf_len); 497 if (rc) 498 break; 499 } 500 kfree(rbuf); 501 out: 502 if (!rc) 503 rc = crypto_shash_final(shash, hash->digest); 504 return rc; 505 } 506 507 static int ima_calc_file_shash(struct file *file, struct ima_digest_data *hash) 508 { 509 struct crypto_shash *tfm; 510 int rc; 511 512 tfm = ima_alloc_tfm(hash->algo); 513 if (IS_ERR(tfm)) 514 return PTR_ERR(tfm); 515 516 rc = ima_calc_file_hash_tfm(file, hash, tfm); 517 518 ima_free_tfm(tfm); 519 520 return rc; 521 } 522 523 /* 524 * ima_calc_file_hash - calculate file hash 525 * 526 * Asynchronous hash (ahash) allows using HW acceleration for calculating 527 * a hash. ahash performance varies for different data sizes on different 528 * crypto accelerators. shash performance might be better for smaller files. 529 * The 'ima.ahash_minsize' module parameter allows specifying the best 530 * minimum file size for using ahash on the system. 531 * 532 * If the ima.ahash_minsize parameter is not specified, this function uses 533 * shash for the hash calculation. If ahash fails, it falls back to using 534 * shash. 535 */ 536 int ima_calc_file_hash(struct file *file, struct ima_digest_data *hash) 537 { 538 loff_t i_size; 539 int rc; 540 struct file *f = file; 541 bool new_file_instance = false; 542 543 /* 544 * For consistency, fail file's opened with the O_DIRECT flag on 545 * filesystems mounted with/without DAX option. 546 */ 547 if (file->f_flags & O_DIRECT) { 548 hash->length = hash_digest_size[ima_hash_algo]; 549 hash->algo = ima_hash_algo; 550 return -EINVAL; 551 } 552 553 /* Open a new file instance in O_RDONLY if we cannot read */ 554 if (!(file->f_mode & FMODE_READ)) { 555 int flags = file->f_flags & ~(O_WRONLY | O_APPEND | 556 O_TRUNC | O_CREAT | O_NOCTTY | O_EXCL); 557 flags |= O_RDONLY; 558 f = dentry_open(&file->f_path, flags, file->f_cred); 559 if (IS_ERR(f)) 560 return PTR_ERR(f); 561 562 new_file_instance = true; 563 } 564 565 i_size = i_size_read(file_inode(f)); 566 567 if (ima_ahash_minsize && i_size >= ima_ahash_minsize) { 568 rc = ima_calc_file_ahash(f, hash); 569 if (!rc) 570 goto out; 571 } 572 573 rc = ima_calc_file_shash(f, hash); 574 out: 575 if (new_file_instance) 576 fput(f); 577 return rc; 578 } 579 580 /* 581 * Calculate the hash of template data 582 */ 583 static int ima_calc_field_array_hash_tfm(struct ima_field_data *field_data, 584 struct ima_template_entry *entry, 585 int tfm_idx) 586 { 587 SHASH_DESC_ON_STACK(shash, ima_algo_array[tfm_idx].tfm); 588 struct ima_template_desc *td = entry->template_desc; 589 int num_fields = entry->template_desc->num_fields; 590 int rc, i; 591 592 shash->tfm = ima_algo_array[tfm_idx].tfm; 593 594 rc = crypto_shash_init(shash); 595 if (rc != 0) 596 return rc; 597 598 for (i = 0; i < num_fields; i++) { 599 u8 buffer[IMA_EVENT_NAME_LEN_MAX + 1] = { 0 }; 600 u8 *data_to_hash = field_data[i].data; 601 u32 datalen = field_data[i].len; 602 u32 datalen_to_hash = !ima_canonical_fmt ? 603 datalen : (__force u32)cpu_to_le32(datalen); 604 605 if (strcmp(td->name, IMA_TEMPLATE_IMA_NAME) != 0) { 606 rc = crypto_shash_update(shash, 607 (const u8 *) &datalen_to_hash, 608 sizeof(datalen_to_hash)); 609 if (rc) 610 break; 611 } else if (strcmp(td->fields[i]->field_id, "n") == 0) { 612 memcpy(buffer, data_to_hash, datalen); 613 data_to_hash = buffer; 614 datalen = IMA_EVENT_NAME_LEN_MAX + 1; 615 } 616 rc = crypto_shash_update(shash, data_to_hash, datalen); 617 if (rc) 618 break; 619 } 620 621 if (!rc) 622 rc = crypto_shash_final(shash, entry->digests[tfm_idx].digest); 623 624 return rc; 625 } 626 627 int ima_calc_field_array_hash(struct ima_field_data *field_data, 628 struct ima_template_entry *entry) 629 { 630 u16 alg_id; 631 int rc, i; 632 633 rc = ima_calc_field_array_hash_tfm(field_data, entry, ima_sha1_idx); 634 if (rc) 635 return rc; 636 637 entry->digests[ima_sha1_idx].alg_id = TPM_ALG_SHA1; 638 639 for (i = 0; i < NR_BANKS(ima_tpm_chip) + ima_extra_slots; i++) { 640 if (i == ima_sha1_idx) 641 continue; 642 643 if (i < NR_BANKS(ima_tpm_chip)) { 644 alg_id = ima_tpm_chip->allocated_banks[i].alg_id; 645 entry->digests[i].alg_id = alg_id; 646 } 647 648 /* for unmapped TPM algorithms digest is still a padded SHA1 */ 649 if (!ima_algo_array[i].tfm) { 650 memcpy(entry->digests[i].digest, 651 entry->digests[ima_sha1_idx].digest, 652 TPM_DIGEST_SIZE); 653 continue; 654 } 655 656 rc = ima_calc_field_array_hash_tfm(field_data, entry, i); 657 if (rc) 658 return rc; 659 } 660 return rc; 661 } 662 663 static int calc_buffer_ahash_atfm(const void *buf, loff_t len, 664 struct ima_digest_data *hash, 665 struct crypto_ahash *tfm) 666 { 667 struct ahash_request *req; 668 struct scatterlist sg; 669 struct crypto_wait wait; 670 int rc, ahash_rc = 0; 671 672 hash->length = crypto_ahash_digestsize(tfm); 673 674 req = ahash_request_alloc(tfm, GFP_KERNEL); 675 if (!req) 676 return -ENOMEM; 677 678 crypto_init_wait(&wait); 679 ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG | 680 CRYPTO_TFM_REQ_MAY_SLEEP, 681 crypto_req_done, &wait); 682 683 rc = ahash_wait(crypto_ahash_init(req), &wait); 684 if (rc) 685 goto out; 686 687 sg_init_one(&sg, buf, len); 688 ahash_request_set_crypt(req, &sg, NULL, len); 689 690 ahash_rc = crypto_ahash_update(req); 691 692 /* wait for the update request to complete */ 693 rc = ahash_wait(ahash_rc, &wait); 694 if (!rc) { 695 ahash_request_set_crypt(req, NULL, hash->digest, 0); 696 rc = ahash_wait(crypto_ahash_final(req), &wait); 697 } 698 out: 699 ahash_request_free(req); 700 return rc; 701 } 702 703 static int calc_buffer_ahash(const void *buf, loff_t len, 704 struct ima_digest_data *hash) 705 { 706 struct crypto_ahash *tfm; 707 int rc; 708 709 tfm = ima_alloc_atfm(hash->algo); 710 if (IS_ERR(tfm)) 711 return PTR_ERR(tfm); 712 713 rc = calc_buffer_ahash_atfm(buf, len, hash, tfm); 714 715 ima_free_atfm(tfm); 716 717 return rc; 718 } 719 720 static int calc_buffer_shash_tfm(const void *buf, loff_t size, 721 struct ima_digest_data *hash, 722 struct crypto_shash *tfm) 723 { 724 SHASH_DESC_ON_STACK(shash, tfm); 725 unsigned int len; 726 int rc; 727 728 shash->tfm = tfm; 729 730 hash->length = crypto_shash_digestsize(tfm); 731 732 rc = crypto_shash_init(shash); 733 if (rc != 0) 734 return rc; 735 736 while (size) { 737 len = size < PAGE_SIZE ? size : PAGE_SIZE; 738 rc = crypto_shash_update(shash, buf, len); 739 if (rc) 740 break; 741 buf += len; 742 size -= len; 743 } 744 745 if (!rc) 746 rc = crypto_shash_final(shash, hash->digest); 747 return rc; 748 } 749 750 static int calc_buffer_shash(const void *buf, loff_t len, 751 struct ima_digest_data *hash) 752 { 753 struct crypto_shash *tfm; 754 int rc; 755 756 tfm = ima_alloc_tfm(hash->algo); 757 if (IS_ERR(tfm)) 758 return PTR_ERR(tfm); 759 760 rc = calc_buffer_shash_tfm(buf, len, hash, tfm); 761 762 ima_free_tfm(tfm); 763 return rc; 764 } 765 766 int ima_calc_buffer_hash(const void *buf, loff_t len, 767 struct ima_digest_data *hash) 768 { 769 int rc; 770 771 if (ima_ahash_minsize && len >= ima_ahash_minsize) { 772 rc = calc_buffer_ahash(buf, len, hash); 773 if (!rc) 774 return 0; 775 } 776 777 return calc_buffer_shash(buf, len, hash); 778 } 779 780 static void ima_pcrread(u32 idx, struct tpm_digest *d) 781 { 782 if (!ima_tpm_chip) 783 return; 784 785 if (tpm_pcr_read(ima_tpm_chip, idx, d) != 0) 786 pr_err("Error Communicating to TPM chip\n"); 787 } 788 789 /* 790 * The boot_aggregate is a cumulative hash over TPM registers 0 - 7. With 791 * TPM 1.2 the boot_aggregate was based on reading the SHA1 PCRs, but with 792 * TPM 2.0 hash agility, TPM chips could support multiple TPM PCR banks, 793 * allowing firmware to configure and enable different banks. 794 * 795 * Knowing which TPM bank is read to calculate the boot_aggregate digest 796 * needs to be conveyed to a verifier. For this reason, use the same 797 * hash algorithm for reading the TPM PCRs as for calculating the boot 798 * aggregate digest as stored in the measurement list. 799 */ 800 static int ima_calc_boot_aggregate_tfm(char *digest, u16 alg_id, 801 struct crypto_shash *tfm) 802 { 803 struct tpm_digest d = { .alg_id = alg_id, .digest = {0} }; 804 int rc; 805 u32 i; 806 SHASH_DESC_ON_STACK(shash, tfm); 807 808 shash->tfm = tfm; 809 810 pr_devel("calculating the boot-aggregate based on TPM bank: %04x\n", 811 d.alg_id); 812 813 rc = crypto_shash_init(shash); 814 if (rc != 0) 815 return rc; 816 817 /* cumulative digest over TPM registers 0-7 */ 818 for (i = TPM_PCR0; i < TPM_PCR8; i++) { 819 ima_pcrread(i, &d); 820 /* now accumulate with current aggregate */ 821 rc = crypto_shash_update(shash, d.digest, 822 crypto_shash_digestsize(tfm)); 823 if (rc != 0) 824 return rc; 825 } 826 /* 827 * Extend cumulative digest over TPM registers 8-9, which contain 828 * measurement for the kernel command line (reg. 8) and image (reg. 9) 829 * in a typical PCR allocation. Registers 8-9 are only included in 830 * non-SHA1 boot_aggregate digests to avoid ambiguity. 831 */ 832 if (alg_id != TPM_ALG_SHA1) { 833 for (i = TPM_PCR8; i < TPM_PCR10; i++) { 834 ima_pcrread(i, &d); 835 rc = crypto_shash_update(shash, d.digest, 836 crypto_shash_digestsize(tfm)); 837 } 838 } 839 if (!rc) 840 crypto_shash_final(shash, digest); 841 return rc; 842 } 843 844 int ima_calc_boot_aggregate(struct ima_digest_data *hash) 845 { 846 struct crypto_shash *tfm; 847 u16 crypto_id, alg_id; 848 int rc, i, bank_idx = -1; 849 850 for (i = 0; i < ima_tpm_chip->nr_allocated_banks; i++) { 851 crypto_id = ima_tpm_chip->allocated_banks[i].crypto_id; 852 if (crypto_id == hash->algo) { 853 bank_idx = i; 854 break; 855 } 856 857 if (crypto_id == HASH_ALGO_SHA256) 858 bank_idx = i; 859 860 if (bank_idx == -1 && crypto_id == HASH_ALGO_SHA1) 861 bank_idx = i; 862 } 863 864 if (bank_idx == -1) { 865 pr_err("No suitable TPM algorithm for boot aggregate\n"); 866 return 0; 867 } 868 869 hash->algo = ima_tpm_chip->allocated_banks[bank_idx].crypto_id; 870 871 tfm = ima_alloc_tfm(hash->algo); 872 if (IS_ERR(tfm)) 873 return PTR_ERR(tfm); 874 875 hash->length = crypto_shash_digestsize(tfm); 876 alg_id = ima_tpm_chip->allocated_banks[bank_idx].alg_id; 877 rc = ima_calc_boot_aggregate_tfm(hash->digest, alg_id, tfm); 878 879 ima_free_tfm(tfm); 880 881 return rc; 882 } 883