security/integrity/ima/ima_crypto.c

   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_PAGE_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 }