linux/security/integrity/ima/ima_crypto.c
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   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 */
  26static unsigned long ima_ahash_minsize;
  27module_param_named(ahash_minsize, ima_ahash_minsize, ulong, 0644);
  28MODULE_PARM_DESC(ahash_minsize, "Minimum file size for ahash use");
  29
  30/* default is 0 - 1 page. */
  31static int ima_maxorder;
  32static unsigned int ima_bufsize = PAGE_SIZE;
  33
  34static 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
  48static 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
  54module_param_named(ahash_bufsize, ima_bufsize, bufsize, 0644);
  55MODULE_PARM_DESC(ahash_bufsize, "Maximum ahash buffer size");
  56
  57static struct crypto_shash *ima_shash_tfm;
  58static struct crypto_ahash *ima_ahash_tfm;
  59
  60struct ima_algo_desc {
  61        struct crypto_shash *tfm;
  62        enum hash_algo algo;
  63};
  64
  65int ima_sha1_idx __ro_after_init;
  66int ima_hash_algo_idx __ro_after_init;
  67/*
  68 * Additional number of slots reserved, as needed, for SHA1
  69 * and IMA default algo.
  70 */
  71int ima_extra_slots __ro_after_init;
  72
  73static struct ima_algo_desc *ima_algo_array;
  74
  75static 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
  91static 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
 115int __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;
 200out_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        }
 208out:
 209        crypto_free_shash(ima_shash_tfm);
 210        return rc;
 211}
 212
 213static 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 */
 242static 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 */
 282static 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
 289static 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
 311static void ima_free_atfm(struct crypto_ahash *tfm)
 312{
 313        if (tfm != ima_ahash_tfm)
 314                crypto_free_ahash(tfm);
 315}
 316
 317static 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
 328static 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);
 426out3:
 427        ima_free_pages(rbuf[0], rbuf_size[0]);
 428        ima_free_pages(rbuf[1], rbuf_size[1]);
 429out2:
 430        if (!rc) {
 431                ahash_request_set_crypt(req, NULL, hash->digest, 0);
 432                rc = ahash_wait(crypto_ahash_final(req), &wait);
 433        }
 434out1:
 435        ahash_request_free(req);
 436        return rc;
 437}
 438
 439static 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
 455static 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);
 500out:
 501        if (!rc)
 502                rc = crypto_shash_final(shash, hash->digest);
 503        return rc;
 504}
 505
 506static 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 */
 535int 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, modified_mode = 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                        /*
 560                         * Cannot open the file again, lets modify f_mode
 561                         * of original and continue
 562                         */
 563                        pr_info_ratelimited("Unable to reopen file for reading.\n");
 564                        f = file;
 565                        f->f_mode |= FMODE_READ;
 566                        modified_mode = true;
 567                } else {
 568                        new_file_instance = true;
 569                }
 570        }
 571
 572        i_size = i_size_read(file_inode(f));
 573
 574        if (ima_ahash_minsize && i_size >= ima_ahash_minsize) {
 575                rc = ima_calc_file_ahash(f, hash);
 576                if (!rc)
 577                        goto out;
 578        }
 579
 580        rc = ima_calc_file_shash(f, hash);
 581out:
 582        if (new_file_instance)
 583                fput(f);
 584        else if (modified_mode)
 585                f->f_mode &= ~FMODE_READ;
 586        return rc;
 587}
 588
 589/*
 590 * Calculate the hash of template data
 591 */
 592static int ima_calc_field_array_hash_tfm(struct ima_field_data *field_data,
 593                                         struct ima_template_entry *entry,
 594                                         int tfm_idx)
 595{
 596        SHASH_DESC_ON_STACK(shash, ima_algo_array[tfm_idx].tfm);
 597        struct ima_template_desc *td = entry->template_desc;
 598        int num_fields = entry->template_desc->num_fields;
 599        int rc, i;
 600
 601        shash->tfm = ima_algo_array[tfm_idx].tfm;
 602
 603        rc = crypto_shash_init(shash);
 604        if (rc != 0)
 605                return rc;
 606
 607        for (i = 0; i < num_fields; i++) {
 608                u8 buffer[IMA_EVENT_NAME_LEN_MAX + 1] = { 0 };
 609                u8 *data_to_hash = field_data[i].data;
 610                u32 datalen = field_data[i].len;
 611                u32 datalen_to_hash =
 612                    !ima_canonical_fmt ? datalen : cpu_to_le32(datalen);
 613
 614                if (strcmp(td->name, IMA_TEMPLATE_IMA_NAME) != 0) {
 615                        rc = crypto_shash_update(shash,
 616                                                (const u8 *) &datalen_to_hash,
 617                                                sizeof(datalen_to_hash));
 618                        if (rc)
 619                                break;
 620                } else if (strcmp(td->fields[i]->field_id, "n") == 0) {
 621                        memcpy(buffer, data_to_hash, datalen);
 622                        data_to_hash = buffer;
 623                        datalen = IMA_EVENT_NAME_LEN_MAX + 1;
 624                }
 625                rc = crypto_shash_update(shash, data_to_hash, datalen);
 626                if (rc)
 627                        break;
 628        }
 629
 630        if (!rc)
 631                rc = crypto_shash_final(shash, entry->digests[tfm_idx].digest);
 632
 633        return rc;
 634}
 635
 636int ima_calc_field_array_hash(struct ima_field_data *field_data,
 637                              struct ima_template_entry *entry)
 638{
 639        u16 alg_id;
 640        int rc, i;
 641
 642        rc = ima_calc_field_array_hash_tfm(field_data, entry, ima_sha1_idx);
 643        if (rc)
 644                return rc;
 645
 646        entry->digests[ima_sha1_idx].alg_id = TPM_ALG_SHA1;
 647
 648        for (i = 0; i < NR_BANKS(ima_tpm_chip) + ima_extra_slots; i++) {
 649                if (i == ima_sha1_idx)
 650                        continue;
 651
 652                if (i < NR_BANKS(ima_tpm_chip)) {
 653                        alg_id = ima_tpm_chip->allocated_banks[i].alg_id;
 654                        entry->digests[i].alg_id = alg_id;
 655                }
 656
 657                /* for unmapped TPM algorithms digest is still a padded SHA1 */
 658                if (!ima_algo_array[i].tfm) {
 659                        memcpy(entry->digests[i].digest,
 660                               entry->digests[ima_sha1_idx].digest,
 661                               TPM_DIGEST_SIZE);
 662                        continue;
 663                }
 664
 665                rc = ima_calc_field_array_hash_tfm(field_data, entry, i);
 666                if (rc)
 667                        return rc;
 668        }
 669        return rc;
 670}
 671
 672static int calc_buffer_ahash_atfm(const void *buf, loff_t len,
 673                                  struct ima_digest_data *hash,
 674                                  struct crypto_ahash *tfm)
 675{
 676        struct ahash_request *req;
 677        struct scatterlist sg;
 678        struct crypto_wait wait;
 679        int rc, ahash_rc = 0;
 680
 681        hash->length = crypto_ahash_digestsize(tfm);
 682
 683        req = ahash_request_alloc(tfm, GFP_KERNEL);
 684        if (!req)
 685                return -ENOMEM;
 686
 687        crypto_init_wait(&wait);
 688        ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
 689                                   CRYPTO_TFM_REQ_MAY_SLEEP,
 690                                   crypto_req_done, &wait);
 691
 692        rc = ahash_wait(crypto_ahash_init(req), &wait);
 693        if (rc)
 694                goto out;
 695
 696        sg_init_one(&sg, buf, len);
 697        ahash_request_set_crypt(req, &sg, NULL, len);
 698
 699        ahash_rc = crypto_ahash_update(req);
 700
 701        /* wait for the update request to complete */
 702        rc = ahash_wait(ahash_rc, &wait);
 703        if (!rc) {
 704                ahash_request_set_crypt(req, NULL, hash->digest, 0);
 705                rc = ahash_wait(crypto_ahash_final(req), &wait);
 706        }
 707out:
 708        ahash_request_free(req);
 709        return rc;
 710}
 711
 712static int calc_buffer_ahash(const void *buf, loff_t len,
 713                             struct ima_digest_data *hash)
 714{
 715        struct crypto_ahash *tfm;
 716        int rc;
 717
 718        tfm = ima_alloc_atfm(hash->algo);
 719        if (IS_ERR(tfm))
 720                return PTR_ERR(tfm);
 721
 722        rc = calc_buffer_ahash_atfm(buf, len, hash, tfm);
 723
 724        ima_free_atfm(tfm);
 725
 726        return rc;
 727}
 728
 729static int calc_buffer_shash_tfm(const void *buf, loff_t size,
 730                                struct ima_digest_data *hash,
 731                                struct crypto_shash *tfm)
 732{
 733        SHASH_DESC_ON_STACK(shash, tfm);
 734        unsigned int len;
 735        int rc;
 736
 737        shash->tfm = tfm;
 738
 739        hash->length = crypto_shash_digestsize(tfm);
 740
 741        rc = crypto_shash_init(shash);
 742        if (rc != 0)
 743                return rc;
 744
 745        while (size) {
 746                len = size < PAGE_SIZE ? size : PAGE_SIZE;
 747                rc = crypto_shash_update(shash, buf, len);
 748                if (rc)
 749                        break;
 750                buf += len;
 751                size -= len;
 752        }
 753
 754        if (!rc)
 755                rc = crypto_shash_final(shash, hash->digest);
 756        return rc;
 757}
 758
 759static int calc_buffer_shash(const void *buf, loff_t len,
 760                             struct ima_digest_data *hash)
 761{
 762        struct crypto_shash *tfm;
 763        int rc;
 764
 765        tfm = ima_alloc_tfm(hash->algo);
 766        if (IS_ERR(tfm))
 767                return PTR_ERR(tfm);
 768
 769        rc = calc_buffer_shash_tfm(buf, len, hash, tfm);
 770
 771        ima_free_tfm(tfm);
 772        return rc;
 773}
 774
 775int ima_calc_buffer_hash(const void *buf, loff_t len,
 776                         struct ima_digest_data *hash)
 777{
 778        int rc;
 779
 780        if (ima_ahash_minsize && len >= ima_ahash_minsize) {
 781                rc = calc_buffer_ahash(buf, len, hash);
 782                if (!rc)
 783                        return 0;
 784        }
 785
 786        return calc_buffer_shash(buf, len, hash);
 787}
 788
 789static void ima_pcrread(u32 idx, struct tpm_digest *d)
 790{
 791        if (!ima_tpm_chip)
 792                return;
 793
 794        if (tpm_pcr_read(ima_tpm_chip, idx, d) != 0)
 795                pr_err("Error Communicating to TPM chip\n");
 796}
 797
 798/*
 799 * The boot_aggregate is a cumulative hash over TPM registers 0 - 7.  With
 800 * TPM 1.2 the boot_aggregate was based on reading the SHA1 PCRs, but with
 801 * TPM 2.0 hash agility, TPM chips could support multiple TPM PCR banks,
 802 * allowing firmware to configure and enable different banks.
 803 *
 804 * Knowing which TPM bank is read to calculate the boot_aggregate digest
 805 * needs to be conveyed to a verifier.  For this reason, use the same
 806 * hash algorithm for reading the TPM PCRs as for calculating the boot
 807 * aggregate digest as stored in the measurement list.
 808 */
 809static int ima_calc_boot_aggregate_tfm(char *digest, u16 alg_id,
 810                                       struct crypto_shash *tfm)
 811{
 812        struct tpm_digest d = { .alg_id = alg_id, .digest = {0} };
 813        int rc;
 814        u32 i;
 815        SHASH_DESC_ON_STACK(shash, tfm);
 816
 817        shash->tfm = tfm;
 818
 819        pr_devel("calculating the boot-aggregate based on TPM bank: %04x\n",
 820                 d.alg_id);
 821
 822        rc = crypto_shash_init(shash);
 823        if (rc != 0)
 824                return rc;
 825
 826        /* cumulative digest over TPM registers 0-7 */
 827        for (i = TPM_PCR0; i < TPM_PCR8; i++) {
 828                ima_pcrread(i, &d);
 829                /* now accumulate with current aggregate */
 830                rc = crypto_shash_update(shash, d.digest,
 831                                         crypto_shash_digestsize(tfm));
 832                if (rc != 0)
 833                        return rc;
 834        }
 835        /*
 836         * Extend cumulative digest over TPM registers 8-9, which contain
 837         * measurement for the kernel command line (reg. 8) and image (reg. 9)
 838         * in a typical PCR allocation. Registers 8-9 are only included in
 839         * non-SHA1 boot_aggregate digests to avoid ambiguity.
 840         */
 841        if (alg_id != TPM_ALG_SHA1) {
 842                for (i = TPM_PCR8; i < TPM_PCR10; i++) {
 843                        ima_pcrread(i, &d);
 844                        rc = crypto_shash_update(shash, d.digest,
 845                                                crypto_shash_digestsize(tfm));
 846                }
 847        }
 848        if (!rc)
 849                crypto_shash_final(shash, digest);
 850        return rc;
 851}
 852
 853int ima_calc_boot_aggregate(struct ima_digest_data *hash)
 854{
 855        struct crypto_shash *tfm;
 856        u16 crypto_id, alg_id;
 857        int rc, i, bank_idx = -1;
 858
 859        for (i = 0; i < ima_tpm_chip->nr_allocated_banks; i++) {
 860                crypto_id = ima_tpm_chip->allocated_banks[i].crypto_id;
 861                if (crypto_id == hash->algo) {
 862                        bank_idx = i;
 863                        break;
 864                }
 865
 866                if (crypto_id == HASH_ALGO_SHA256)
 867                        bank_idx = i;
 868
 869                if (bank_idx == -1 && crypto_id == HASH_ALGO_SHA1)
 870                        bank_idx = i;
 871        }
 872
 873        if (bank_idx == -1) {
 874                pr_err("No suitable TPM algorithm for boot aggregate\n");
 875                return 0;
 876        }
 877
 878        hash->algo = ima_tpm_chip->allocated_banks[bank_idx].crypto_id;
 879
 880        tfm = ima_alloc_tfm(hash->algo);
 881        if (IS_ERR(tfm))
 882                return PTR_ERR(tfm);
 883
 884        hash->length = crypto_shash_digestsize(tfm);
 885        alg_id = ima_tpm_chip->allocated_banks[bank_idx].alg_id;
 886        rc = ima_calc_boot_aggregate_tfm(hash->digest, alg_id, tfm);
 887
 888        ima_free_tfm(tfm);
 889
 890        return rc;
 891}
 892