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_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 out:
 209         crypto_free_shash(ima_shash_tfm);
 210         return rc;
 211 }
 212
 213 static void ima_free_tfm(struct crypto_shash *tfm)
 214 {
 215         int i;
 216
 217         if (tfm == ima_shash_tfm)
 218                 return;
 219
 220         for (i = 0; i < NR_BANKS(ima_tpm_chip) + ima_extra_slots; i++)
 221                 if (ima_algo_array[i].tfm == tfm)
 222                         return;
 223
 224         crypto_free_shash(tfm);
 225 }
 226
 227 /**
 228  * ima_alloc_pages() - Allocate contiguous pages.
 229  * @max_size:       Maximum amount of memory to allocate.
 230  * @allocated_size: Returned size of actual allocation.
 231  * @last_warn:      Should the min_size allocation warn or not.
 232  *
 233  * Tries to do opportunistic allocation for memory first trying to allocate
 234  * max_size amount of memory and then splitting that until zero order is
 235  * reached. Allocation is tried without generating allocation warnings unless
 236  * last_warn is set. Last_warn set affects only last allocation of zero order.
 237  *
 238  * By default, ima_maxorder is 0 and it is equivalent to kmalloc(GFP_KERNEL)
 239  *
 240  * Return pointer to allocated memory, or NULL on failure.
 241  */
 242 static void *ima_alloc_pages(loff_t max_size, size_t *allocated_size,
 243                              int last_warn)
 244 {
 245         void *ptr;
 246         int order = ima_maxorder;
 247         gfp_t gfp_mask = __GFP_RECLAIM | __GFP_NOWARN | __GFP_NORETRY;
 248
 249         if (order)
 250                 order = min(get_order(max_size), order);
 251
 252         for (; order; order--) {
 253                 ptr = (void *)__get_free_pages(gfp_mask, order);
 254                 if (ptr) {
 255                         *allocated_size = PAGE_SIZE << order;
 256                         return ptr;
 257                 }
 258         }
 259
 260         /* order is zero - one page */
 261
 262         gfp_mask = GFP_KERNEL;
 263
 264         if (!last_warn)
 265                 gfp_mask |= __GFP_NOWARN;
 266
 267         ptr = (void *)__get_free_pages(gfp_mask, 0);
 268         if (ptr) {
 269                 *allocated_size = PAGE_SIZE;
 270                 return ptr;
 271         }
 272
 273         *allocated_size = 0;
 274         return NULL;
 275 }
 276
 277 /**
 278  * ima_free_pages() - Free pages allocated by ima_alloc_pages().
 279  * @ptr:  Pointer to allocated pages.
 280  * @size: Size of allocated buffer.
 281  */
 282 static void ima_free_pages(void *ptr, size_t size)
 283 {
 284         if (!ptr)
 285                 return;
 286         free_pages((unsigned long)ptr, get_order(size));
 287 }
 288
 289 static struct crypto_ahash *ima_alloc_atfm(enum hash_algo algo)
 290 {
 291         struct crypto_ahash *tfm = ima_ahash_tfm;
 292         int rc;
 293
 294         if (algo < 0 || algo >= HASH_ALGO__LAST)
 295                 algo = ima_hash_algo;
 296
 297         if (algo != ima_hash_algo || !tfm) {
 298                 tfm = crypto_alloc_ahash(hash_algo_name[algo], 0, 0);
 299                 if (!IS_ERR(tfm)) {
 300                         if (algo == ima_hash_algo)
 301                                 ima_ahash_tfm = tfm;
 302                 } else {
 303                         rc = PTR_ERR(tfm);
 304                         pr_err("Can not allocate %s (reason: %d)\n",
 305                                hash_algo_name[algo], rc);
 306                 }
 307         }
 308         return tfm;
 309 }
 310
 311 static void ima_free_atfm(struct crypto_ahash *tfm)
 312 {
 313         if (tfm != ima_ahash_tfm)
 314                 crypto_free_ahash(tfm);
 315 }
 316
 317 static inline int ahash_wait(int err, struct crypto_wait *wait)
 318 {
 319
 320         err = crypto_wait_req(err, wait);
 321
 322         if (err)
 323                 pr_crit_ratelimited("ahash calculation failed: err: %d\n", err);
 324
 325         return err;
 326 }
 327
 328 static int ima_calc_file_hash_atfm(struct file *file,
 329                                    struct ima_digest_data *hash,
 330                                    struct crypto_ahash *tfm)
 331 {
 332         loff_t i_size, offset;
 333         char *rbuf[2] = { NULL, };
 334         int rc, rbuf_len, active = 0, ahash_rc = 0;
 335         struct ahash_request *req;
 336         struct scatterlist sg[1];
 337         struct crypto_wait wait;
 338         size_t rbuf_size[2];
 339
 340         hash->length = crypto_ahash_digestsize(tfm);
 341
 342         req = ahash_request_alloc(tfm, GFP_KERNEL);
 343         if (!req)
 344                 return -ENOMEM;
 345
 346         crypto_init_wait(&wait);
 347         ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
 348                                    CRYPTO_TFM_REQ_MAY_SLEEP,
 349                                    crypto_req_done, &wait);
 350
 351         rc = ahash_wait(crypto_ahash_init(req), &wait);
 352         if (rc)
 353                 goto out1;
 354
 355         i_size = i_size_read(file_inode(file));
 356
 357         if (i_size == 0)
 358                 goto out2;
 359
 360         /*
 361          * Try to allocate maximum size of memory.
 362          * Fail if even a single page cannot be allocated.
 363          */
 364         rbuf[0] = ima_alloc_pages(i_size, &rbuf_size[0], 1);
 365         if (!rbuf[0]) {
 366                 rc = -ENOMEM;
 367                 goto out1;
 368         }
 369
 370         /* Only allocate one buffer if that is enough. */
 371         if (i_size > rbuf_size[0]) {
 372                 /*
 373                  * Try to allocate secondary buffer. If that fails fallback to
 374                  * using single buffering. Use previous memory allocation size
 375                  * as baseline for possible allocation size.
 376                  */
 377                 rbuf[1] = ima_alloc_pages(i_size - rbuf_size[0],
 378                                           &rbuf_size[1], 0);
 379         }
 380
 381         for (offset = 0; offset < i_size; offset += rbuf_len) {
 382                 if (!rbuf[1] && offset) {
 383                         /* Not using two buffers, and it is not the first
 384                          * read/request, wait for the completion of the
 385                          * previous ahash_update() request.
 386                          */
 387                         rc = ahash_wait(ahash_rc, &wait);
 388                         if (rc)
 389                                 goto out3;
 390                 }
 391                 /* read buffer */
 392                 rbuf_len = min_t(loff_t, i_size - offset, rbuf_size[active]);
 393                 rc = integrity_kernel_read(file, offset, rbuf[active],
 394                                            rbuf_len);
 395                 if (rc != rbuf_len) {
 396                         if (rc >= 0)
 397                                 rc = -EINVAL;
 398                         /*
 399                          * Forward current rc, do not overwrite with return value
 400                          * from ahash_wait()
 401                          */
 402                         ahash_wait(ahash_rc, &wait);
 403                         goto out3;
 404                 }
 405
 406                 if (rbuf[1] && offset) {
 407                         /* Using two buffers, and it is not the first
 408                          * read/request, wait for the completion of the
 409                          * previous ahash_update() request.
 410                          */
 411                         rc = ahash_wait(ahash_rc, &wait);
 412                         if (rc)
 413                                 goto out3;
 414                 }
 415
 416                 sg_init_one(&sg[0], rbuf[active], rbuf_len);
 417                 ahash_request_set_crypt(req, sg, NULL, rbuf_len);
 418
 419                 ahash_rc = crypto_ahash_update(req);
 420
 421                 if (rbuf[1])
 422                         active = !active; /* swap buffers, if we use two */
 423         }
 424         /* wait for the last update request to complete */
 425         rc = ahash_wait(ahash_rc, &wait);
 426 out3:
 427         ima_free_pages(rbuf[0], rbuf_size[0]);
 428         ima_free_pages(rbuf[1], rbuf_size[1]);
 429 out2:
 430         if (!rc) {
 431                 ahash_request_set_crypt(req, NULL, hash->digest, 0);
 432                 rc = ahash_wait(crypto_ahash_final(req), &wait);
 433         }
 434 out1:
 435         ahash_request_free(req);
 436         return rc;
 437 }
 438
 439 static int ima_calc_file_ahash(struct file *file, struct ima_digest_data *hash)
 440 {
 441         struct crypto_ahash *tfm;
 442         int rc;
 443
 444         tfm = ima_alloc_atfm(hash->algo);
 445         if (IS_ERR(tfm))
 446                 return PTR_ERR(tfm);
 447
 448         rc = ima_calc_file_hash_atfm(file, hash, tfm);
 449
 450         ima_free_atfm(tfm);
 451
 452         return rc;
 453 }
 454
 455 static int ima_calc_file_hash_tfm(struct file *file,
 456                                   struct ima_digest_data *hash,
 457                                   struct crypto_shash *tfm)
 458 {
 459         loff_t i_size, offset = 0;
 460         char *rbuf;
 461         int rc;
 462         SHASH_DESC_ON_STACK(shash, tfm);
 463
 464         shash->tfm = tfm;
 465
 466         hash->length = crypto_shash_digestsize(tfm);
 467
 468         rc = crypto_shash_init(shash);
 469         if (rc != 0)
 470                 return rc;
 471
 472         i_size = i_size_read(file_inode(file));
 473
 474         if (i_size == 0)
 475                 goto out;
 476
 477         rbuf = kzalloc(PAGE_SIZE, GFP_KERNEL);
 478         if (!rbuf)
 479                 return -ENOMEM;
 480
 481         while (offset < i_size) {
 482                 int rbuf_len;
 483
 484                 rbuf_len = integrity_kernel_read(file, offset, rbuf, PAGE_SIZE);
 485                 if (rbuf_len < 0) {
 486                         rc = rbuf_len;
 487                         break;
 488                 }
 489                 if (rbuf_len == 0) {    /* unexpected EOF */
 490                         rc = -EINVAL;
 491                         break;
 492                 }
 493                 offset += rbuf_len;
 494
 495                 rc = crypto_shash_update(shash, rbuf, rbuf_len);
 496                 if (rc)
 497                         break;
 498         }
 499         kfree(rbuf);
 500 out:
 501         if (!rc)
 502                 rc = crypto_shash_final(shash, hash->digest);
 503         return rc;
 504 }
 505
 506 static int ima_calc_file_shash(struct file *file, 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_file_hash_tfm(file, hash, tfm);
 516
 517         ima_free_tfm(tfm);
 518
 519         return rc;
 520 }
 521
 522 /*
 523  * ima_calc_file_hash - calculate file hash
 524  *
 525  * Asynchronous hash (ahash) allows using HW acceleration for calculating
 526  * a hash. ahash performance varies for different data sizes on different
 527  * crypto accelerators. shash performance might be better for smaller files.
 528  * The 'ima.ahash_minsize' module parameter allows specifying the best
 529  * minimum file size for using ahash on the system.
 530  *
 531  * If the ima.ahash_minsize parameter is not specified, this function uses
 532  * shash for the hash calculation.  If ahash fails, it falls back to using
 533  * shash.
 534  */
 535 int ima_calc_file_hash(struct file *file, struct ima_digest_data *hash)
 536 {
 537         loff_t i_size;
 538         int rc;
 539         struct file *f = file;
 540         bool new_file_instance = false;
 541
 542         /*
 543          * For consistency, fail file's opened with the O_DIRECT flag on
 544          * filesystems mounted with/without DAX option.
 545          */
 546         if (file->f_flags & O_DIRECT) {
 547                 hash->length = hash_digest_size[ima_hash_algo];
 548                 hash->algo = ima_hash_algo;
 549                 return -EINVAL;
 550         }
 551
 552         /* Open a new file instance in O_RDONLY if we cannot read */
 553         if (!(file->f_mode & FMODE_READ)) {
 554                 int flags = file->f_flags & ~(O_WRONLY | O_APPEND |
 555                                 O_TRUNC | O_CREAT | O_NOCTTY | O_EXCL);
 556                 flags |= O_RDONLY;
 557                 f = dentry_open(&file->f_path, flags, file->f_cred);
 558                 if (IS_ERR(f))
 559                         return PTR_ERR(f);
 560
 561                 new_file_instance = true;
 562         }
 563
 564         i_size = i_size_read(file_inode(f));
 565
 566         if (ima_ahash_minsize && i_size >= ima_ahash_minsize) {
 567                 rc = ima_calc_file_ahash(f, hash);
 568                 if (!rc)
 569                         goto out;
 570         }
 571
 572         rc = ima_calc_file_shash(f, hash);
 573 out:
 574         if (new_file_instance)
 575                 fput(f);
 576         return rc;
 577 }
 578
 579 /*
 580  * Calculate the hash of template data
 581  */
 582 static int ima_calc_field_array_hash_tfm(struct ima_field_data *field_data,
 583                                          struct ima_template_entry *entry,
 584                                          int tfm_idx)
 585 {
 586         SHASH_DESC_ON_STACK(shash, ima_algo_array[tfm_idx].tfm);
 587         struct ima_template_desc *td = entry->template_desc;
 588         int num_fields = entry->template_desc->num_fields;
 589         int rc, i;
 590
 591         shash->tfm = ima_algo_array[tfm_idx].tfm;
 592
 593         rc = crypto_shash_init(shash);
 594         if (rc != 0)
 595                 return rc;
 596
 597         for (i = 0; i < num_fields; i++) {
 598                 u8 buffer[IMA_EVENT_NAME_LEN_MAX + 1] = { 0 };
 599                 u8 *data_to_hash = field_data[i].data;
 600                 u32 datalen = field_data[i].len;
 601                 u32 datalen_to_hash = !ima_canonical_fmt ?
 602                                 datalen : (__force u32)cpu_to_le32(datalen);
 603
 604                 if (strcmp(td->name, IMA_TEMPLATE_IMA_NAME) != 0) {
 605                         rc = crypto_shash_update(shash,
 606                                                 (const u8 *) &datalen_to_hash,
 607                                                 sizeof(datalen_to_hash));
 608                         if (rc)
 609                                 break;
 610                 } else if (strcmp(td->fields[i]->field_id, "n") == 0) {
 611                         memcpy(buffer, data_to_hash, datalen);
 612                         data_to_hash = buffer;
 613                         datalen = IMA_EVENT_NAME_LEN_MAX + 1;
 614                 }
 615                 rc = crypto_shash_update(shash, data_to_hash, datalen);
 616                 if (rc)
 617                         break;
 618         }
 619
 620         if (!rc)
 621                 rc = crypto_shash_final(shash, entry->digests[tfm_idx].digest);
 622
 623         return rc;
 624 }
 625
 626 int ima_calc_field_array_hash(struct ima_field_data *field_data,
 627                               struct ima_template_entry *entry)
 628 {
 629         u16 alg_id;
 630         int rc, i;
 631
 632         rc = ima_calc_field_array_hash_tfm(field_data, entry, ima_sha1_idx);
 633         if (rc)
 634                 return rc;
 635
 636         entry->digests[ima_sha1_idx].alg_id = TPM_ALG_SHA1;
 637
 638         for (i = 0; i < NR_BANKS(ima_tpm_chip) + ima_extra_slots; i++) {
 639                 if (i == ima_sha1_idx)
 640                         continue;
 641
 642                 if (i < NR_BANKS(ima_tpm_chip)) {
 643                         alg_id = ima_tpm_chip->allocated_banks[i].alg_id;
 644                         entry->digests[i].alg_id = alg_id;
 645                 }
 646
 647                 /* for unmapped TPM algorithms digest is still a padded SHA1 */
 648                 if (!ima_algo_array[i].tfm) {
 649                         memcpy(entry->digests[i].digest,
 650                                entry->digests[ima_sha1_idx].digest,
 651                                TPM_DIGEST_SIZE);
 652                         continue;
 653                 }
 654
 655                 rc = ima_calc_field_array_hash_tfm(field_data, entry, i);
 656                 if (rc)
 657                         return rc;
 658         }
 659         return rc;
 660 }
 661
 662 static int calc_buffer_ahash_atfm(const void *buf, loff_t len,
 663                                   struct ima_digest_data *hash,
 664                                   struct crypto_ahash *tfm)
 665 {
 666         struct ahash_request *req;
 667         struct scatterlist sg;
 668         struct crypto_wait wait;
 669         int rc, ahash_rc = 0;
 670
 671         hash->length = crypto_ahash_digestsize(tfm);
 672
 673         req = ahash_request_alloc(tfm, GFP_KERNEL);
 674         if (!req)
 675                 return -ENOMEM;
 676
 677         crypto_init_wait(&wait);
 678         ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
 679                                    CRYPTO_TFM_REQ_MAY_SLEEP,
 680                                    crypto_req_done, &wait);
 681
 682         rc = ahash_wait(crypto_ahash_init(req), &wait);
 683         if (rc)
 684                 goto out;
 685
 686         sg_init_one(&sg, buf, len);
 687         ahash_request_set_crypt(req, &sg, NULL, len);
 688
 689         ahash_rc = crypto_ahash_update(req);
 690
 691         /* wait for the update request to complete */
 692         rc = ahash_wait(ahash_rc, &wait);
 693         if (!rc) {
 694                 ahash_request_set_crypt(req, NULL, hash->digest, 0);
 695                 rc = ahash_wait(crypto_ahash_final(req), &wait);
 696         }
 697 out:
 698         ahash_request_free(req);
 699         return rc;
 700 }
 701
 702 static int calc_buffer_ahash(const void *buf, loff_t len,
 703                              struct ima_digest_data *hash)
 704 {
 705         struct crypto_ahash *tfm;
 706         int rc;
 707
 708         tfm = ima_alloc_atfm(hash->algo);
 709         if (IS_ERR(tfm))
 710                 return PTR_ERR(tfm);
 711
 712         rc = calc_buffer_ahash_atfm(buf, len, hash, tfm);
 713
 714         ima_free_atfm(tfm);
 715
 716         return rc;
 717 }
 718
 719 static int calc_buffer_shash_tfm(const void *buf, loff_t size,
 720                                 struct ima_digest_data *hash,
 721                                 struct crypto_shash *tfm)
 722 {
 723         SHASH_DESC_ON_STACK(shash, tfm);
 724         unsigned int len;
 725         int rc;
 726
 727         shash->tfm = tfm;
 728
 729         hash->length = crypto_shash_digestsize(tfm);
 730
 731         rc = crypto_shash_init(shash);
 732         if (rc != 0)
 733                 return rc;
 734
 735         while (size) {
 736                 len = size < PAGE_SIZE ? size : PAGE_SIZE;
 737                 rc = crypto_shash_update(shash, buf, len);
 738                 if (rc)
 739                         break;
 740                 buf += len;
 741                 size -= len;
 742         }
 743
 744         if (!rc)
 745                 rc = crypto_shash_final(shash, hash->digest);
 746         return rc;
 747 }
 748
 749 static int calc_buffer_shash(const void *buf, loff_t len,
 750                              struct ima_digest_data *hash)
 751 {
 752         struct crypto_shash *tfm;
 753         int rc;
 754
 755         tfm = ima_alloc_tfm(hash->algo);
 756         if (IS_ERR(tfm))
 757                 return PTR_ERR(tfm);
 758
 759         rc = calc_buffer_shash_tfm(buf, len, hash, tfm);
 760
 761         ima_free_tfm(tfm);
 762         return rc;
 763 }
 764
 765 int ima_calc_buffer_hash(const void *buf, loff_t len,
 766                          struct ima_digest_data *hash)
 767 {
 768         int rc;
 769
 770         if (ima_ahash_minsize && len >= ima_ahash_minsize) {
 771                 rc = calc_buffer_ahash(buf, len, hash);
 772                 if (!rc)
 773                         return 0;
 774         }
 775
 776         return calc_buffer_shash(buf, len, hash);
 777 }
 778
 779 static void ima_pcrread(u32 idx, struct tpm_digest *d)
 780 {
 781         if (!ima_tpm_chip)
 782                 return;
 783
 784         if (tpm_pcr_read(ima_tpm_chip, idx, d) != 0)
 785                 pr_err("Error Communicating to TPM chip\n");
 786 }
 787
 788 /*
 789  * The boot_aggregate is a cumulative hash over TPM registers 0 - 7.  With
 790  * TPM 1.2 the boot_aggregate was based on reading the SHA1 PCRs, but with
 791  * TPM 2.0 hash agility, TPM chips could support multiple TPM PCR banks,
 792  * allowing firmware to configure and enable different banks.
 793  *
 794  * Knowing which TPM bank is read to calculate the boot_aggregate digest
 795  * needs to be conveyed to a verifier.  For this reason, use the same
 796  * hash algorithm for reading the TPM PCRs as for calculating the boot
 797  * aggregate digest as stored in the measurement list.
 798  */
 799 static int ima_calc_boot_aggregate_tfm(char *digest, u16 alg_id,
 800                                        struct crypto_shash *tfm)
 801 {
 802         struct tpm_digest d = { .alg_id = alg_id, .digest = {0} };
 803         int rc;
 804         u32 i;
 805         SHASH_DESC_ON_STACK(shash, tfm);
 806
 807         shash->tfm = tfm;
 808
 809         pr_devel("calculating the boot-aggregate based on TPM bank: %04x\n",
 810                  d.alg_id);
 811
 812         rc = crypto_shash_init(shash);
 813         if (rc != 0)
 814                 return rc;
 815
 816         /* cumulative digest over TPM registers 0-7 */
 817         for (i = TPM_PCR0; i < TPM_PCR8; i++) {
 818                 ima_pcrread(i, &d);
 819                 /* now accumulate with current aggregate */
 820                 rc = crypto_shash_update(shash, d.digest,
 821                                          crypto_shash_digestsize(tfm));
 822                 if (rc != 0)
 823                         return rc;
 824         }
 825         /*
 826          * Extend cumulative digest over TPM registers 8-9, which contain
 827          * measurement for the kernel command line (reg. 8) and image (reg. 9)
 828          * in a typical PCR allocation. Registers 8-9 are only included in
 829          * non-SHA1 boot_aggregate digests to avoid ambiguity.
 830          */
 831         if (alg_id != TPM_ALG_SHA1) {
 832                 for (i = TPM_PCR8; i < TPM_PCR10; i++) {
 833                         ima_pcrread(i, &d);
 834                         rc = crypto_shash_update(shash, d.digest,
 835                                                 crypto_shash_digestsize(tfm));
 836                 }
 837         }
 838         if (!rc)
 839                 crypto_shash_final(shash, digest);
 840         return rc;
 841 }
 842
 843 int ima_calc_boot_aggregate(struct ima_digest_data *hash)
 844 {
 845         struct crypto_shash *tfm;
 846         u16 crypto_id, alg_id;
 847         int rc, i, bank_idx = -1;
 848
 849         for (i = 0; i < ima_tpm_chip->nr_allocated_banks; i++) {
 850                 crypto_id = ima_tpm_chip->allocated_banks[i].crypto_id;
 851                 if (crypto_id == hash->algo) {
 852                         bank_idx = i;
 853                         break;
 854                 }
 855
 856                 if (crypto_id == HASH_ALGO_SHA256)
 857                         bank_idx = i;
 858
 859                 if (bank_idx == -1 && crypto_id == HASH_ALGO_SHA1)
 860                         bank_idx = i;
 861         }
 862
 863         if (bank_idx == -1) {
 864                 pr_err("No suitable TPM algorithm for boot aggregate\n");
 865                 return 0;
 866         }
 867
 868         hash->algo = ima_tpm_chip->allocated_banks[bank_idx].crypto_id;
 869
 870         tfm = ima_alloc_tfm(hash->algo);
 871         if (IS_ERR(tfm))
 872                 return PTR_ERR(tfm);
 873
 874         hash->length = crypto_shash_digestsize(tfm);
 875         alg_id = ima_tpm_chip->allocated_banks[bank_idx].alg_id;
 876         rc = ima_calc_boot_aggregate_tfm(hash->digest, alg_id, tfm);
 877
 878         ima_free_tfm(tfm);
 879
 880         return rc;
 881 }