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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 14 15 #include <linux/kernel.h> 16 #include <linux/moduleparam.h> 17 #include <linux/ratelimit.h> 18 #include <linux/file.h> 19 #include <linux/crypto.h> 20 #include <linux/scatterlist.h> 21 #include <linux/err.h> 22 #include <linux/slab.h> 23 #include <crypto/hash.h> 24 25 #include "ima.h" 26 27 /* minimum file size for ahash use */ 28 static unsigned long ima_ahash_minsize; 29 module_param_named(ahash_minsize, ima_ahash_minsize, ulong, 0644); 30 MODULE_PARM_DESC(ahash_minsize, "Minimum file size for ahash use"); 31 32 /* default is 0 - 1 page. */ 33 static int ima_maxorder; 34 static unsigned int ima_bufsize = PAGE_SIZE; 35 36 static int param_set_bufsize(const char *val, const struct kernel_param *kp) 37 { 38 unsigned long long size; 39 int order; 40 41 size = memparse(val, NULL); 42 order = get_order(size); 43 if (order >= MAX_ORDER) 44 return -EINVAL; 45 ima_maxorder = order; 46 ima_bufsize = PAGE_SIZE << order; 47 return 0; 48 } 49 50 static const struct kernel_param_ops param_ops_bufsize = { 51 .set = param_set_bufsize, 52 .get = param_get_uint, 53 }; 54 #define param_check_bufsize(name, p) __param_check(name, p, unsigned int) 55 56 module_param_named(ahash_bufsize, ima_bufsize, bufsize, 0644); 57 MODULE_PARM_DESC(ahash_bufsize, "Maximum ahash buffer size"); 58 59 static struct crypto_shash *ima_shash_tfm; 60 static struct crypto_ahash *ima_ahash_tfm; 61 62 int __init ima_init_crypto(void) 63 { 64 long rc; 65 66 ima_shash_tfm = crypto_alloc_shash(hash_algo_name[ima_hash_algo], 0, 0); 67 if (IS_ERR(ima_shash_tfm)) { 68 rc = PTR_ERR(ima_shash_tfm); 69 pr_err("Can not allocate %s (reason: %ld)\n", 70 hash_algo_name[ima_hash_algo], rc); 71 return rc; 72 } 73 pr_info("Allocated hash algorithm: %s\n", 74 hash_algo_name[ima_hash_algo]); 75 return 0; 76 } 77 78 static struct crypto_shash *ima_alloc_tfm(enum hash_algo algo) 79 { 80 struct crypto_shash *tfm = ima_shash_tfm; 81 int rc; 82 83 if (algo < 0 || algo >= HASH_ALGO__LAST) 84 algo = ima_hash_algo; 85 86 if (algo != ima_hash_algo) { 87 tfm = crypto_alloc_shash(hash_algo_name[algo], 0, 0); 88 if (IS_ERR(tfm)) { 89 rc = PTR_ERR(tfm); 90 pr_err("Can not allocate %s (reason: %d)\n", 91 hash_algo_name[algo], rc); 92 } 93 } 94 return tfm; 95 } 96 97 static void ima_free_tfm(struct crypto_shash *tfm) 98 { 99 if (tfm != ima_shash_tfm) 100 crypto_free_shash(tfm); 101 } 102 103 /** 104 * ima_alloc_pages() - Allocate contiguous pages. 105 * @max_size: Maximum amount of memory to allocate. 106 * @allocated_size: Returned size of actual allocation. 107 * @last_warn: Should the min_size allocation warn or not. 108 * 109 * Tries to do opportunistic allocation for memory first trying to allocate 110 * max_size amount of memory and then splitting that until zero order is 111 * reached. Allocation is tried without generating allocation warnings unless 112 * last_warn is set. Last_warn set affects only last allocation of zero order. 113 * 114 * By default, ima_maxorder is 0 and it is equivalent to kmalloc(GFP_KERNEL) 115 * 116 * Return pointer to allocated memory, or NULL on failure. 117 */ 118 static void *ima_alloc_pages(loff_t max_size, size_t *allocated_size, 119 int last_warn) 120 { 121 void *ptr; 122 int order = ima_maxorder; 123 gfp_t gfp_mask = __GFP_RECLAIM | __GFP_NOWARN | __GFP_NORETRY; 124 125 if (order) 126 order = min(get_order(max_size), order); 127 128 for (; order; order--) { 129 ptr = (void *)__get_free_pages(gfp_mask, order); 130 if (ptr) { 131 *allocated_size = PAGE_SIZE << order; 132 return ptr; 133 } 134 } 135 136 /* order is zero - one page */ 137 138 gfp_mask = GFP_KERNEL; 139 140 if (!last_warn) 141 gfp_mask |= __GFP_NOWARN; 142 143 ptr = (void *)__get_free_pages(gfp_mask, 0); 144 if (ptr) { 145 *allocated_size = PAGE_SIZE; 146 return ptr; 147 } 148 149 *allocated_size = 0; 150 return NULL; 151 } 152 153 /** 154 * ima_free_pages() - Free pages allocated by ima_alloc_pages(). 155 * @ptr: Pointer to allocated pages. 156 * @size: Size of allocated buffer. 157 */ 158 static void ima_free_pages(void *ptr, size_t size) 159 { 160 if (!ptr) 161 return; 162 free_pages((unsigned long)ptr, get_order(size)); 163 } 164 165 static struct crypto_ahash *ima_alloc_atfm(enum hash_algo algo) 166 { 167 struct crypto_ahash *tfm = ima_ahash_tfm; 168 int rc; 169 170 if (algo < 0 || algo >= HASH_ALGO__LAST) 171 algo = ima_hash_algo; 172 173 if (algo != ima_hash_algo || !tfm) { 174 tfm = crypto_alloc_ahash(hash_algo_name[algo], 0, 0); 175 if (!IS_ERR(tfm)) { 176 if (algo == ima_hash_algo) 177 ima_ahash_tfm = tfm; 178 } else { 179 rc = PTR_ERR(tfm); 180 pr_err("Can not allocate %s (reason: %d)\n", 181 hash_algo_name[algo], rc); 182 } 183 } 184 return tfm; 185 } 186 187 static void ima_free_atfm(struct crypto_ahash *tfm) 188 { 189 if (tfm != ima_ahash_tfm) 190 crypto_free_ahash(tfm); 191 } 192 193 static inline int ahash_wait(int err, struct crypto_wait *wait) 194 { 195 196 err = crypto_wait_req(err, wait); 197 198 if (err) 199 pr_crit_ratelimited("ahash calculation failed: err: %d\n", err); 200 201 return err; 202 } 203 204 static int ima_calc_file_hash_atfm(struct file *file, 205 struct ima_digest_data *hash, 206 struct crypto_ahash *tfm) 207 { 208 loff_t i_size, offset; 209 char *rbuf[2] = { NULL, }; 210 int rc, rbuf_len, active = 0, ahash_rc = 0; 211 struct ahash_request *req; 212 struct scatterlist sg[1]; 213 struct crypto_wait wait; 214 size_t rbuf_size[2]; 215 216 hash->length = crypto_ahash_digestsize(tfm); 217 218 req = ahash_request_alloc(tfm, GFP_KERNEL); 219 if (!req) 220 return -ENOMEM; 221 222 crypto_init_wait(&wait); 223 ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG | 224 CRYPTO_TFM_REQ_MAY_SLEEP, 225 crypto_req_done, &wait); 226 227 rc = ahash_wait(crypto_ahash_init(req), &wait); 228 if (rc) 229 goto out1; 230 231 i_size = i_size_read(file_inode(file)); 232 233 if (i_size == 0) 234 goto out2; 235 236 /* 237 * Try to allocate maximum size of memory. 238 * Fail if even a single page cannot be allocated. 239 */ 240 rbuf[0] = ima_alloc_pages(i_size, &rbuf_size[0], 1); 241 if (!rbuf[0]) { 242 rc = -ENOMEM; 243 goto out1; 244 } 245 246 /* Only allocate one buffer if that is enough. */ 247 if (i_size > rbuf_size[0]) { 248 /* 249 * Try to allocate secondary buffer. If that fails fallback to 250 * using single buffering. Use previous memory allocation size 251 * as baseline for possible allocation size. 252 */ 253 rbuf[1] = ima_alloc_pages(i_size - rbuf_size[0], 254 &rbuf_size[1], 0); 255 } 256 257 for (offset = 0; offset < i_size; offset += rbuf_len) { 258 if (!rbuf[1] && offset) { 259 /* Not using two buffers, and it is not the first 260 * read/request, wait for the completion of the 261 * previous ahash_update() request. 262 */ 263 rc = ahash_wait(ahash_rc, &wait); 264 if (rc) 265 goto out3; 266 } 267 /* read buffer */ 268 rbuf_len = min_t(loff_t, i_size - offset, rbuf_size[active]); 269 rc = integrity_kernel_read(file, offset, rbuf[active], 270 rbuf_len); 271 if (rc != rbuf_len) 272 goto out3; 273 274 if (rbuf[1] && offset) { 275 /* Using two buffers, and it is not the first 276 * read/request, wait for the completion of the 277 * previous ahash_update() request. 278 */ 279 rc = ahash_wait(ahash_rc, &wait); 280 if (rc) 281 goto out3; 282 } 283 284 sg_init_one(&sg[0], rbuf[active], rbuf_len); 285 ahash_request_set_crypt(req, sg, NULL, rbuf_len); 286 287 ahash_rc = crypto_ahash_update(req); 288 289 if (rbuf[1]) 290 active = !active; /* swap buffers, if we use two */ 291 } 292 /* wait for the last update request to complete */ 293 rc = ahash_wait(ahash_rc, &wait); 294 out3: 295 ima_free_pages(rbuf[0], rbuf_size[0]); 296 ima_free_pages(rbuf[1], rbuf_size[1]); 297 out2: 298 if (!rc) { 299 ahash_request_set_crypt(req, NULL, hash->digest, 0); 300 rc = ahash_wait(crypto_ahash_final(req), &wait); 301 } 302 out1: 303 ahash_request_free(req); 304 return rc; 305 } 306 307 static int ima_calc_file_ahash(struct file *file, struct ima_digest_data *hash) 308 { 309 struct crypto_ahash *tfm; 310 int rc; 311 312 tfm = ima_alloc_atfm(hash->algo); 313 if (IS_ERR(tfm)) 314 return PTR_ERR(tfm); 315 316 rc = ima_calc_file_hash_atfm(file, hash, tfm); 317 318 ima_free_atfm(tfm); 319 320 return rc; 321 } 322 323 static int ima_calc_file_hash_tfm(struct file *file, 324 struct ima_digest_data *hash, 325 struct crypto_shash *tfm) 326 { 327 loff_t i_size, offset = 0; 328 char *rbuf; 329 int rc; 330 SHASH_DESC_ON_STACK(shash, tfm); 331 332 shash->tfm = tfm; 333 334 hash->length = crypto_shash_digestsize(tfm); 335 336 rc = crypto_shash_init(shash); 337 if (rc != 0) 338 return rc; 339 340 i_size = i_size_read(file_inode(file)); 341 342 if (i_size == 0) 343 goto out; 344 345 rbuf = kzalloc(PAGE_SIZE, GFP_KERNEL); 346 if (!rbuf) 347 return -ENOMEM; 348 349 while (offset < i_size) { 350 int rbuf_len; 351 352 rbuf_len = integrity_kernel_read(file, offset, rbuf, PAGE_SIZE); 353 if (rbuf_len < 0) { 354 rc = rbuf_len; 355 break; 356 } 357 if (rbuf_len == 0) 358 break; 359 offset += rbuf_len; 360 361 rc = crypto_shash_update(shash, rbuf, rbuf_len); 362 if (rc) 363 break; 364 } 365 kfree(rbuf); 366 out: 367 if (!rc) 368 rc = crypto_shash_final(shash, hash->digest); 369 return rc; 370 } 371 372 static int ima_calc_file_shash(struct file *file, struct ima_digest_data *hash) 373 { 374 struct crypto_shash *tfm; 375 int rc; 376 377 tfm = ima_alloc_tfm(hash->algo); 378 if (IS_ERR(tfm)) 379 return PTR_ERR(tfm); 380 381 rc = ima_calc_file_hash_tfm(file, hash, tfm); 382 383 ima_free_tfm(tfm); 384 385 return rc; 386 } 387 388 /* 389 * ima_calc_file_hash - calculate file hash 390 * 391 * Asynchronous hash (ahash) allows using HW acceleration for calculating 392 * a hash. ahash performance varies for different data sizes on different 393 * crypto accelerators. shash performance might be better for smaller files. 394 * The 'ima.ahash_minsize' module parameter allows specifying the best 395 * minimum file size for using ahash on the system. 396 * 397 * If the ima.ahash_minsize parameter is not specified, this function uses 398 * shash for the hash calculation. If ahash fails, it falls back to using 399 * shash. 400 */ 401 int ima_calc_file_hash(struct file *file, struct ima_digest_data *hash) 402 { 403 loff_t i_size; 404 int rc; 405 struct file *f = file; 406 bool new_file_instance = false, modified_flags = false; 407 408 /* 409 * For consistency, fail file's opened with the O_DIRECT flag on 410 * filesystems mounted with/without DAX option. 411 */ 412 if (file->f_flags & O_DIRECT) { 413 hash->length = hash_digest_size[ima_hash_algo]; 414 hash->algo = ima_hash_algo; 415 return -EINVAL; 416 } 417 418 /* Open a new file instance in O_RDONLY if we cannot read */ 419 if (!(file->f_mode & FMODE_READ)) { 420 int flags = file->f_flags & ~(O_WRONLY | O_APPEND | 421 O_TRUNC | O_CREAT | O_NOCTTY | O_EXCL); 422 flags |= O_RDONLY; 423 f = dentry_open(&file->f_path, flags, file->f_cred); 424 if (IS_ERR(f)) { 425 /* 426 * Cannot open the file again, lets modify f_flags 427 * of original and continue 428 */ 429 pr_info_ratelimited("Unable to reopen file for reading.\n"); 430 f = file; 431 f->f_flags |= FMODE_READ; 432 modified_flags = true; 433 } else { 434 new_file_instance = true; 435 } 436 } 437 438 i_size = i_size_read(file_inode(f)); 439 440 if (ima_ahash_minsize && i_size >= ima_ahash_minsize) { 441 rc = ima_calc_file_ahash(f, hash); 442 if (!rc) 443 goto out; 444 } 445 446 rc = ima_calc_file_shash(f, hash); 447 out: 448 if (new_file_instance) 449 fput(f); 450 else if (modified_flags) 451 f->f_flags &= ~FMODE_READ; 452 return rc; 453 } 454 455 /* 456 * Calculate the hash of template data 457 */ 458 static int ima_calc_field_array_hash_tfm(struct ima_field_data *field_data, 459 struct ima_template_desc *td, 460 int num_fields, 461 struct ima_digest_data *hash, 462 struct crypto_shash *tfm) 463 { 464 SHASH_DESC_ON_STACK(shash, tfm); 465 int rc, i; 466 467 shash->tfm = tfm; 468 469 hash->length = crypto_shash_digestsize(tfm); 470 471 rc = crypto_shash_init(shash); 472 if (rc != 0) 473 return rc; 474 475 for (i = 0; i < num_fields; i++) { 476 u8 buffer[IMA_EVENT_NAME_LEN_MAX + 1] = { 0 }; 477 u8 *data_to_hash = field_data[i].data; 478 u32 datalen = field_data[i].len; 479 u32 datalen_to_hash = 480 !ima_canonical_fmt ? datalen : cpu_to_le32(datalen); 481 482 if (strcmp(td->name, IMA_TEMPLATE_IMA_NAME) != 0) { 483 rc = crypto_shash_update(shash, 484 (const u8 *) &datalen_to_hash, 485 sizeof(datalen_to_hash)); 486 if (rc) 487 break; 488 } else if (strcmp(td->fields[i]->field_id, "n") == 0) { 489 memcpy(buffer, data_to_hash, datalen); 490 data_to_hash = buffer; 491 datalen = IMA_EVENT_NAME_LEN_MAX + 1; 492 } 493 rc = crypto_shash_update(shash, data_to_hash, datalen); 494 if (rc) 495 break; 496 } 497 498 if (!rc) 499 rc = crypto_shash_final(shash, hash->digest); 500 501 return rc; 502 } 503 504 int ima_calc_field_array_hash(struct ima_field_data *field_data, 505 struct ima_template_desc *desc, int num_fields, 506 struct ima_digest_data *hash) 507 { 508 struct crypto_shash *tfm; 509 int rc; 510 511 tfm = ima_alloc_tfm(hash->algo); 512 if (IS_ERR(tfm)) 513 return PTR_ERR(tfm); 514 515 rc = ima_calc_field_array_hash_tfm(field_data, desc, num_fields, 516 hash, tfm); 517 518 ima_free_tfm(tfm); 519 520 return rc; 521 } 522 523 static int calc_buffer_ahash_atfm(const void *buf, loff_t len, 524 struct ima_digest_data *hash, 525 struct crypto_ahash *tfm) 526 { 527 struct ahash_request *req; 528 struct scatterlist sg; 529 struct crypto_wait wait; 530 int rc, ahash_rc = 0; 531 532 hash->length = crypto_ahash_digestsize(tfm); 533 534 req = ahash_request_alloc(tfm, GFP_KERNEL); 535 if (!req) 536 return -ENOMEM; 537 538 crypto_init_wait(&wait); 539 ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG | 540 CRYPTO_TFM_REQ_MAY_SLEEP, 541 crypto_req_done, &wait); 542 543 rc = ahash_wait(crypto_ahash_init(req), &wait); 544 if (rc) 545 goto out; 546 547 sg_init_one(&sg, buf, len); 548 ahash_request_set_crypt(req, &sg, NULL, len); 549 550 ahash_rc = crypto_ahash_update(req); 551 552 /* wait for the update request to complete */ 553 rc = ahash_wait(ahash_rc, &wait); 554 if (!rc) { 555 ahash_request_set_crypt(req, NULL, hash->digest, 0); 556 rc = ahash_wait(crypto_ahash_final(req), &wait); 557 } 558 out: 559 ahash_request_free(req); 560 return rc; 561 } 562 563 static int calc_buffer_ahash(const void *buf, loff_t len, 564 struct ima_digest_data *hash) 565 { 566 struct crypto_ahash *tfm; 567 int rc; 568 569 tfm = ima_alloc_atfm(hash->algo); 570 if (IS_ERR(tfm)) 571 return PTR_ERR(tfm); 572 573 rc = calc_buffer_ahash_atfm(buf, len, hash, tfm); 574 575 ima_free_atfm(tfm); 576 577 return rc; 578 } 579 580 static int calc_buffer_shash_tfm(const void *buf, loff_t size, 581 struct ima_digest_data *hash, 582 struct crypto_shash *tfm) 583 { 584 SHASH_DESC_ON_STACK(shash, tfm); 585 unsigned int len; 586 int rc; 587 588 shash->tfm = tfm; 589 590 hash->length = crypto_shash_digestsize(tfm); 591 592 rc = crypto_shash_init(shash); 593 if (rc != 0) 594 return rc; 595 596 while (size) { 597 len = size < PAGE_SIZE ? size : PAGE_SIZE; 598 rc = crypto_shash_update(shash, buf, len); 599 if (rc) 600 break; 601 buf += len; 602 size -= len; 603 } 604 605 if (!rc) 606 rc = crypto_shash_final(shash, hash->digest); 607 return rc; 608 } 609 610 static int calc_buffer_shash(const void *buf, loff_t len, 611 struct ima_digest_data *hash) 612 { 613 struct crypto_shash *tfm; 614 int rc; 615 616 tfm = ima_alloc_tfm(hash->algo); 617 if (IS_ERR(tfm)) 618 return PTR_ERR(tfm); 619 620 rc = calc_buffer_shash_tfm(buf, len, hash, tfm); 621 622 ima_free_tfm(tfm); 623 return rc; 624 } 625 626 int ima_calc_buffer_hash(const void *buf, loff_t len, 627 struct ima_digest_data *hash) 628 { 629 int rc; 630 631 if (ima_ahash_minsize && len >= ima_ahash_minsize) { 632 rc = calc_buffer_ahash(buf, len, hash); 633 if (!rc) 634 return 0; 635 } 636 637 return calc_buffer_shash(buf, len, hash); 638 } 639 640 static void __init ima_pcrread(u32 idx, struct tpm_digest *d) 641 { 642 if (!ima_tpm_chip) 643 return; 644 645 if (tpm_pcr_read(ima_tpm_chip, idx, d) != 0) 646 pr_err("Error Communicating to TPM chip\n"); 647 } 648 649 /* 650 * Calculate the boot aggregate hash 651 */ 652 static int __init ima_calc_boot_aggregate_tfm(char *digest, 653 struct crypto_shash *tfm) 654 { 655 struct tpm_digest d = { .alg_id = TPM_ALG_SHA1, .digest = {0} }; 656 int rc; 657 u32 i; 658 SHASH_DESC_ON_STACK(shash, tfm); 659 660 shash->tfm = tfm; 661 662 rc = crypto_shash_init(shash); 663 if (rc != 0) 664 return rc; 665 666 /* cumulative sha1 over tpm registers 0-7 */ 667 for (i = TPM_PCR0; i < TPM_PCR8; i++) { 668 ima_pcrread(i, &d); 669 /* now accumulate with current aggregate */ 670 rc = crypto_shash_update(shash, d.digest, TPM_DIGEST_SIZE); 671 } 672 if (!rc) 673 crypto_shash_final(shash, digest); 674 return rc; 675 } 676 677 int __init ima_calc_boot_aggregate(struct ima_digest_data *hash) 678 { 679 struct crypto_shash *tfm; 680 int rc; 681 682 tfm = ima_alloc_tfm(hash->algo); 683 if (IS_ERR(tfm)) 684 return PTR_ERR(tfm); 685 686 hash->length = crypto_shash_digestsize(tfm); 687 rc = ima_calc_boot_aggregate_tfm(hash->digest, tfm); 688 689 ima_free_tfm(tfm); 690 691 return rc; 692 } 693