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