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(ptr: 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
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(alg_name: hash_algo_name[ima_hash_algo], type: 0, mask: 0);
80 if (IS_ERR(ptr: ima_shash_tfm)) {
81 rc = PTR_ERR(ptr: 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(alg_name: hash_algo_name[algo], type: 0, mask: 0);
107 if (IS_ERR(ptr: tfm)) {
108 rc = PTR_ERR(ptr: 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 size: 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(ptr: ima_algo_array[i].tfm)) {
168 if (algo == HASH_ALGO_SHA1) {
169 rc = PTR_ERR(ptr: 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(algo: HASH_ALGO_SHA1);
184 if (IS_ERR(ptr: ima_algo_array[ima_sha1_idx].tfm)) {
185 rc = PTR_ERR(ptr: 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(tfm: ima_algo_array[i].tfm);
207 }
208 kfree(objp: ima_algo_array);
209out:
210 crypto_free_shash(tfm: ima_shash_tfm);
211 return rc;
212}
213
214static void ima_free_tfm(struct crypto_shash *tfm)
215{
216 int i;
217
218 if (tfm == ima_shash_tfm)
219 return;
220
221 for (i = 0; i < NR_BANKS(ima_tpm_chip) + ima_extra_slots; i++)
222 if (ima_algo_array[i].tfm == tfm)
223 return;
224
225 crypto_free_shash(tfm);
226}
227
228/**
229 * ima_alloc_pages() - Allocate contiguous pages.
230 * @max_size: Maximum amount of memory to allocate.
231 * @allocated_size: Returned size of actual allocation.
232 * @last_warn: Should the min_size allocation warn or not.
233 *
234 * Tries to do opportunistic allocation for memory first trying to allocate
235 * max_size amount of memory and then splitting that until zero order is
236 * reached. Allocation is tried without generating allocation warnings unless
237 * last_warn is set. Last_warn set affects only last allocation of zero order.
238 *
239 * By default, ima_maxorder is 0 and it is equivalent to kmalloc(GFP_KERNEL)
240 *
241 * Return pointer to allocated memory, or NULL on failure.
242 */
243static void *ima_alloc_pages(loff_t max_size, size_t *allocated_size,
244 int last_warn)
245{
246 void *ptr;
247 int order = ima_maxorder;
248 gfp_t gfp_mask = __GFP_RECLAIM | __GFP_NOWARN | __GFP_NORETRY;
249
250 if (order)
251 order = min(get_order(max_size), order);
252
253 for (; order; order--) {
254 ptr = (void *)__get_free_pages(gfp_mask, order);
255 if (ptr) {
256 *allocated_size = PAGE_SIZE << order;
257 return ptr;
258 }
259 }
260
261 /* order is zero - one page */
262
263 gfp_mask = GFP_KERNEL;
264
265 if (!last_warn)
266 gfp_mask |= __GFP_NOWARN;
267
268 ptr = (void *)__get_free_pages(gfp_mask, order: 0);
269 if (ptr) {
270 *allocated_size = PAGE_SIZE;
271 return ptr;
272 }
273
274 *allocated_size = 0;
275 return NULL;
276}
277
278/**
279 * ima_free_pages() - Free pages allocated by ima_alloc_pages().
280 * @ptr: Pointer to allocated pages.
281 * @size: Size of allocated buffer.
282 */
283static void ima_free_pages(void *ptr, size_t size)
284{
285 if (!ptr)
286 return;
287 free_pages(addr: (unsigned long)ptr, order: get_order(size));
288}
289
290static struct crypto_ahash *ima_alloc_atfm(enum hash_algo algo)
291{
292 struct crypto_ahash *tfm = ima_ahash_tfm;
293 int rc;
294
295 if (algo < 0 || algo >= HASH_ALGO__LAST)
296 algo = ima_hash_algo;
297
298 if (algo != ima_hash_algo || !tfm) {
299 tfm = crypto_alloc_ahash(alg_name: hash_algo_name[algo], type: 0, mask: 0);
300 if (!IS_ERR(ptr: tfm)) {
301 if (algo == ima_hash_algo)
302 ima_ahash_tfm = tfm;
303 } else {
304 rc = PTR_ERR(ptr: tfm);
305 pr_err("Can not allocate %s (reason: %d)\n",
306 hash_algo_name[algo], rc);
307 }
308 }
309 return tfm;
310}
311
312static void ima_free_atfm(struct crypto_ahash *tfm)
313{
314 if (tfm != ima_ahash_tfm)
315 crypto_free_ahash(tfm);
316}
317
318static inline int ahash_wait(int err, struct crypto_wait *wait)
319{
320
321 err = crypto_wait_req(err, wait);
322
323 if (err)
324 pr_crit_ratelimited("ahash calculation failed: err: %d\n", err);
325
326 return err;
327}
328
329static int ima_calc_file_hash_atfm(struct file *file,
330 struct ima_digest_data *hash,
331 struct crypto_ahash *tfm)
332{
333 loff_t i_size, offset;
334 char *rbuf[2] = { NULL, };
335 int rc, rbuf_len, active = 0, ahash_rc = 0;
336 struct ahash_request *req;
337 struct scatterlist sg[1];
338 struct crypto_wait wait;
339 size_t rbuf_size[2];
340
341 hash->length = crypto_ahash_digestsize(tfm);
342
343 req = ahash_request_alloc(tfm, GFP_KERNEL);
344 if (!req)
345 return -ENOMEM;
346
347 crypto_init_wait(wait: &wait);
348 ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
349 CRYPTO_TFM_REQ_MAY_SLEEP,
350 compl: crypto_req_done, data: &wait);
351
352 rc = ahash_wait(err: crypto_ahash_init(req), wait: &wait);
353 if (rc)
354 goto out1;
355
356 i_size = i_size_read(inode: file_inode(f: file));
357
358 if (i_size == 0)
359 goto out2;
360
361 /*
362 * Try to allocate maximum size of memory.
363 * Fail if even a single page cannot be allocated.
364 */
365 rbuf[0] = ima_alloc_pages(max_size: i_size, allocated_size: &rbuf_size[0], last_warn: 1);
366 if (!rbuf[0]) {
367 rc = -ENOMEM;
368 goto out1;
369 }
370
371 /* Only allocate one buffer if that is enough. */
372 if (i_size > rbuf_size[0]) {
373 /*
374 * Try to allocate secondary buffer. If that fails fallback to
375 * using single buffering. Use previous memory allocation size
376 * as baseline for possible allocation size.
377 */
378 rbuf[1] = ima_alloc_pages(max_size: i_size - rbuf_size[0],
379 allocated_size: &rbuf_size[1], last_warn: 0);
380 }
381
382 for (offset = 0; offset < i_size; offset += rbuf_len) {
383 if (!rbuf[1] && offset) {
384 /* Not using two buffers, and it is not the first
385 * read/request, wait for the completion of the
386 * previous ahash_update() request.
387 */
388 rc = ahash_wait(err: ahash_rc, wait: &wait);
389 if (rc)
390 goto out3;
391 }
392 /* read buffer */
393 rbuf_len = min_t(loff_t, i_size - offset, rbuf_size[active]);
394 rc = integrity_kernel_read(file, offset, addr: rbuf[active],
395 count: rbuf_len);
396 if (rc != rbuf_len) {
397 if (rc >= 0)
398 rc = -EINVAL;
399 /*
400 * Forward current rc, do not overwrite with return value
401 * from ahash_wait()
402 */
403 ahash_wait(err: ahash_rc, wait: &wait);
404 goto out3;
405 }
406
407 if (rbuf[1] && offset) {
408 /* Using two buffers, and it is not the first
409 * read/request, wait for the completion of the
410 * previous ahash_update() request.
411 */
412 rc = ahash_wait(err: ahash_rc, wait: &wait);
413 if (rc)
414 goto out3;
415 }
416
417 sg_init_one(&sg[0], rbuf[active], rbuf_len);
418 ahash_request_set_crypt(req, src: sg, NULL, nbytes: rbuf_len);
419
420 ahash_rc = crypto_ahash_update(req);
421
422 if (rbuf[1])
423 active = !active; /* swap buffers, if we use two */
424 }
425 /* wait for the last update request to complete */
426 rc = ahash_wait(err: ahash_rc, wait: &wait);
427out3:
428 ima_free_pages(ptr: rbuf[0], size: rbuf_size[0]);
429 ima_free_pages(ptr: rbuf[1], size: rbuf_size[1]);
430out2:
431 if (!rc) {
432 ahash_request_set_crypt(req, NULL, result: hash->digest, nbytes: 0);
433 rc = ahash_wait(err: crypto_ahash_final(req), wait: &wait);
434 }
435out1:
436 ahash_request_free(req);
437 return rc;
438}
439
440static int ima_calc_file_ahash(struct file *file, struct ima_digest_data *hash)
441{
442 struct crypto_ahash *tfm;
443 int rc;
444
445 tfm = ima_alloc_atfm(algo: hash->algo);
446 if (IS_ERR(ptr: tfm))
447 return PTR_ERR(ptr: tfm);
448
449 rc = ima_calc_file_hash_atfm(file, hash, tfm);
450
451 ima_free_atfm(tfm);
452
453 return rc;
454}
455
456static int ima_calc_file_hash_tfm(struct file *file,
457 struct ima_digest_data *hash,
458 struct crypto_shash *tfm)
459{
460 loff_t i_size, offset = 0;
461 char *rbuf;
462 int rc;
463 SHASH_DESC_ON_STACK(shash, tfm);
464
465 shash->tfm = tfm;
466
467 hash->length = crypto_shash_digestsize(tfm);
468
469 rc = crypto_shash_init(desc: shash);
470 if (rc != 0)
471 return rc;
472
473 i_size = i_size_read(inode: file_inode(f: file));
474
475 if (i_size == 0)
476 goto out;
477
478 rbuf = kzalloc(PAGE_SIZE, GFP_KERNEL);
479 if (!rbuf)
480 return -ENOMEM;
481
482 while (offset < i_size) {
483 int rbuf_len;
484
485 rbuf_len = integrity_kernel_read(file, offset, addr: rbuf, PAGE_SIZE);
486 if (rbuf_len < 0) {
487 rc = rbuf_len;
488 break;
489 }
490 if (rbuf_len == 0) { /* unexpected EOF */
491 rc = -EINVAL;
492 break;
493 }
494 offset += rbuf_len;
495
496 rc = crypto_shash_update(desc: shash, data: rbuf, len: rbuf_len);
497 if (rc)
498 break;
499 }
500 kfree(objp: rbuf);
501out:
502 if (!rc)
503 rc = crypto_shash_final(desc: shash, out: hash->digest);
504 return rc;
505}
506
507static int ima_calc_file_shash(struct file *file, struct ima_digest_data *hash)
508{
509 struct crypto_shash *tfm;
510 int rc;
511
512 tfm = ima_alloc_tfm(algo: hash->algo);
513 if (IS_ERR(ptr: tfm))
514 return PTR_ERR(ptr: tfm);
515
516 rc = ima_calc_file_hash_tfm(file, hash, tfm);
517
518 ima_free_tfm(tfm);
519
520 return rc;
521}
522
523/*
524 * ima_calc_file_hash - calculate file hash
525 *
526 * Asynchronous hash (ahash) allows using HW acceleration for calculating
527 * a hash. ahash performance varies for different data sizes on different
528 * crypto accelerators. shash performance might be better for smaller files.
529 * The 'ima.ahash_minsize' module parameter allows specifying the best
530 * minimum file size for using ahash on the system.
531 *
532 * If the ima.ahash_minsize parameter is not specified, this function uses
533 * shash for the hash calculation. If ahash fails, it falls back to using
534 * shash.
535 */
536int ima_calc_file_hash(struct file *file, struct ima_digest_data *hash)
537{
538 loff_t i_size;
539 int rc;
540 struct file *f = file;
541 bool new_file_instance = false;
542
543 /*
544 * For consistency, fail file's opened with the O_DIRECT flag on
545 * filesystems mounted with/without DAX option.
546 */
547 if (file->f_flags & O_DIRECT) {
548 hash->length = hash_digest_size[ima_hash_algo];
549 hash->algo = ima_hash_algo;
550 return -EINVAL;
551 }
552
553 /* Open a new file instance in O_RDONLY if we cannot read */
554 if (!(file->f_mode & FMODE_READ)) {
555 int flags = file->f_flags & ~(O_WRONLY | O_APPEND |
556 O_TRUNC | O_CREAT | O_NOCTTY | O_EXCL);
557 flags |= O_RDONLY;
558 f = dentry_open(path: &file->f_path, flags, creds: file->f_cred);
559 if (IS_ERR(ptr: f))
560 return PTR_ERR(ptr: f);
561
562 new_file_instance = true;
563 }
564
565 i_size = i_size_read(inode: file_inode(f));
566
567 if (ima_ahash_minsize && i_size >= ima_ahash_minsize) {
568 rc = ima_calc_file_ahash(file: f, hash);
569 if (!rc)
570 goto out;
571 }
572
573 rc = ima_calc_file_shash(file: f, hash);
574out:
575 if (new_file_instance)
576 fput(f);
577 return rc;
578}
579
580/*
581 * Calculate the hash of template data
582 */
583static int ima_calc_field_array_hash_tfm(struct ima_field_data *field_data,
584 struct ima_template_entry *entry,
585 int tfm_idx)
586{
587 SHASH_DESC_ON_STACK(shash, ima_algo_array[tfm_idx].tfm);
588 struct ima_template_desc *td = entry->template_desc;
589 int num_fields = entry->template_desc->num_fields;
590 int rc, i;
591
592 shash->tfm = ima_algo_array[tfm_idx].tfm;
593
594 rc = crypto_shash_init(desc: shash);
595 if (rc != 0)
596 return rc;
597
598 for (i = 0; i < num_fields; i++) {
599 u8 buffer[IMA_EVENT_NAME_LEN_MAX + 1] = { 0 };
600 u8 *data_to_hash = field_data[i].data;
601 u32 datalen = field_data[i].len;
602 u32 datalen_to_hash = !ima_canonical_fmt ?
603 datalen : (__force u32)cpu_to_le32(datalen);
604
605 if (strcmp(td->name, IMA_TEMPLATE_IMA_NAME) != 0) {
606 rc = crypto_shash_update(desc: shash,
607 data: (const u8 *) &datalen_to_hash,
608 len: sizeof(datalen_to_hash));
609 if (rc)
610 break;
611 } else if (strcmp(td->fields[i]->field_id, "n") == 0) {
612 memcpy(buffer, data_to_hash, datalen);
613 data_to_hash = buffer;
614 datalen = IMA_EVENT_NAME_LEN_MAX + 1;
615 }
616 rc = crypto_shash_update(desc: shash, data: data_to_hash, len: datalen);
617 if (rc)
618 break;
619 }
620
621 if (!rc)
622 rc = crypto_shash_final(desc: shash, out: entry->digests[tfm_idx].digest);
623
624 return rc;
625}
626
627int ima_calc_field_array_hash(struct ima_field_data *field_data,
628 struct ima_template_entry *entry)
629{
630 u16 alg_id;
631 int rc, i;
632
633 rc = ima_calc_field_array_hash_tfm(field_data, entry, tfm_idx: ima_sha1_idx);
634 if (rc)
635 return rc;
636
637 entry->digests[ima_sha1_idx].alg_id = TPM_ALG_SHA1;
638
639 for (i = 0; i < NR_BANKS(ima_tpm_chip) + ima_extra_slots; i++) {
640 if (i == ima_sha1_idx)
641 continue;
642
643 if (i < NR_BANKS(ima_tpm_chip)) {
644 alg_id = ima_tpm_chip->allocated_banks[i].alg_id;
645 entry->digests[i].alg_id = alg_id;
646 }
647
648 /* for unmapped TPM algorithms digest is still a padded SHA1 */
649 if (!ima_algo_array[i].tfm) {
650 memcpy(entry->digests[i].digest,
651 entry->digests[ima_sha1_idx].digest,
652 TPM_DIGEST_SIZE);
653 continue;
654 }
655
656 rc = ima_calc_field_array_hash_tfm(field_data, entry, tfm_idx: i);
657 if (rc)
658 return rc;
659 }
660 return rc;
661}
662
663static int calc_buffer_ahash_atfm(const void *buf, loff_t len,
664 struct ima_digest_data *hash,
665 struct crypto_ahash *tfm)
666{
667 struct ahash_request *req;
668 struct scatterlist sg;
669 struct crypto_wait wait;
670 int rc, ahash_rc = 0;
671
672 hash->length = crypto_ahash_digestsize(tfm);
673
674 req = ahash_request_alloc(tfm, GFP_KERNEL);
675 if (!req)
676 return -ENOMEM;
677
678 crypto_init_wait(wait: &wait);
679 ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
680 CRYPTO_TFM_REQ_MAY_SLEEP,
681 compl: crypto_req_done, data: &wait);
682
683 rc = ahash_wait(err: crypto_ahash_init(req), wait: &wait);
684 if (rc)
685 goto out;
686
687 sg_init_one(&sg, buf, len);
688 ahash_request_set_crypt(req, src: &sg, NULL, nbytes: len);
689
690 ahash_rc = crypto_ahash_update(req);
691
692 /* wait for the update request to complete */
693 rc = ahash_wait(err: ahash_rc, wait: &wait);
694 if (!rc) {
695 ahash_request_set_crypt(req, NULL, result: hash->digest, nbytes: 0);
696 rc = ahash_wait(err: crypto_ahash_final(req), wait: &wait);
697 }
698out:
699 ahash_request_free(req);
700 return rc;
701}
702
703static int calc_buffer_ahash(const void *buf, loff_t len,
704 struct ima_digest_data *hash)
705{
706 struct crypto_ahash *tfm;
707 int rc;
708
709 tfm = ima_alloc_atfm(algo: hash->algo);
710 if (IS_ERR(ptr: tfm))
711 return PTR_ERR(ptr: tfm);
712
713 rc = calc_buffer_ahash_atfm(buf, len, hash, tfm);
714
715 ima_free_atfm(tfm);
716
717 return rc;
718}
719
720static int calc_buffer_shash_tfm(const void *buf, loff_t size,
721 struct ima_digest_data *hash,
722 struct crypto_shash *tfm)
723{
724 SHASH_DESC_ON_STACK(shash, tfm);
725 unsigned int len;
726 int rc;
727
728 shash->tfm = tfm;
729
730 hash->length = crypto_shash_digestsize(tfm);
731
732 rc = crypto_shash_init(desc: shash);
733 if (rc != 0)
734 return rc;
735
736 while (size) {
737 len = size < PAGE_SIZE ? size : PAGE_SIZE;
738 rc = crypto_shash_update(desc: shash, data: buf, len);
739 if (rc)
740 break;
741 buf += len;
742 size -= len;
743 }
744
745 if (!rc)
746 rc = crypto_shash_final(desc: shash, out: hash->digest);
747 return rc;
748}
749
750static int calc_buffer_shash(const void *buf, loff_t len,
751 struct ima_digest_data *hash)
752{
753 struct crypto_shash *tfm;
754 int rc;
755
756 tfm = ima_alloc_tfm(algo: hash->algo);
757 if (IS_ERR(ptr: tfm))
758 return PTR_ERR(ptr: tfm);
759
760 rc = calc_buffer_shash_tfm(buf, size: len, hash, tfm);
761
762 ima_free_tfm(tfm);
763 return rc;
764}
765
766int ima_calc_buffer_hash(const void *buf, loff_t len,
767 struct ima_digest_data *hash)
768{
769 int rc;
770
771 if (ima_ahash_minsize && len >= ima_ahash_minsize) {
772 rc = calc_buffer_ahash(buf, len, hash);
773 if (!rc)
774 return 0;
775 }
776
777 return calc_buffer_shash(buf, len, hash);
778}
779
780static void ima_pcrread(u32 idx, struct tpm_digest *d)
781{
782 if (!ima_tpm_chip)
783 return;
784
785 if (tpm_pcr_read(chip: ima_tpm_chip, pcr_idx: idx, digest: d) != 0)
786 pr_err("Error Communicating to TPM chip\n");
787}
788
789/*
790 * The boot_aggregate is a cumulative hash over TPM registers 0 - 7. With
791 * TPM 1.2 the boot_aggregate was based on reading the SHA1 PCRs, but with
792 * TPM 2.0 hash agility, TPM chips could support multiple TPM PCR banks,
793 * allowing firmware to configure and enable different banks.
794 *
795 * Knowing which TPM bank is read to calculate the boot_aggregate digest
796 * needs to be conveyed to a verifier. For this reason, use the same
797 * hash algorithm for reading the TPM PCRs as for calculating the boot
798 * aggregate digest as stored in the measurement list.
799 */
800static int ima_calc_boot_aggregate_tfm(char *digest, u16 alg_id,
801 struct crypto_shash *tfm)
802{
803 struct tpm_digest d = { .alg_id = alg_id, .digest = {0} };
804 int rc;
805 u32 i;
806 SHASH_DESC_ON_STACK(shash, tfm);
807
808 shash->tfm = tfm;
809
810 pr_devel("calculating the boot-aggregate based on TPM bank: %04x\n",
811 d.alg_id);
812
813 rc = crypto_shash_init(desc: shash);
814 if (rc != 0)
815 return rc;
816
817 /* cumulative digest over TPM registers 0-7 */
818 for (i = TPM_PCR0; i < TPM_PCR8; i++) {
819 ima_pcrread(idx: i, d: &d);
820 /* now accumulate with current aggregate */
821 rc = crypto_shash_update(desc: shash, data: d.digest,
822 len: crypto_shash_digestsize(tfm));
823 if (rc != 0)
824 return rc;
825 }
826 /*
827 * Extend cumulative digest over TPM registers 8-9, which contain
828 * measurement for the kernel command line (reg. 8) and image (reg. 9)
829 * in a typical PCR allocation. Registers 8-9 are only included in
830 * non-SHA1 boot_aggregate digests to avoid ambiguity.
831 */
832 if (alg_id != TPM_ALG_SHA1) {
833 for (i = TPM_PCR8; i < TPM_PCR10; i++) {
834 ima_pcrread(idx: i, d: &d);
835 rc = crypto_shash_update(desc: shash, data: d.digest,
836 len: crypto_shash_digestsize(tfm));
837 }
838 }
839 if (!rc)
840 crypto_shash_final(desc: shash, out: digest);
841 return rc;
842}
843
844int ima_calc_boot_aggregate(struct ima_digest_data *hash)
845{
846 struct crypto_shash *tfm;
847 u16 crypto_id, alg_id;
848 int rc, i, bank_idx = -1;
849
850 for (i = 0; i < ima_tpm_chip->nr_allocated_banks; i++) {
851 crypto_id = ima_tpm_chip->allocated_banks[i].crypto_id;
852 if (crypto_id == hash->algo) {
853 bank_idx = i;
854 break;
855 }
856
857 if (crypto_id == HASH_ALGO_SHA256)
858 bank_idx = i;
859
860 if (bank_idx == -1 && crypto_id == HASH_ALGO_SHA1)
861 bank_idx = i;
862 }
863
864 if (bank_idx == -1) {
865 pr_err("No suitable TPM algorithm for boot aggregate\n");
866 return 0;
867 }
868
869 hash->algo = ima_tpm_chip->allocated_banks[bank_idx].crypto_id;
870
871 tfm = ima_alloc_tfm(algo: hash->algo);
872 if (IS_ERR(ptr: tfm))
873 return PTR_ERR(ptr: tfm);
874
875 hash->length = crypto_shash_digestsize(tfm);
876 alg_id = ima_tpm_chip->allocated_banks[bank_idx].alg_id;
877 rc = ima_calc_boot_aggregate_tfm(digest: hash->digest, alg_id, tfm);
878
879 ima_free_tfm(tfm);
880
881 return rc;
882}
883

source code of linux/security/integrity/ima/ima_crypto.c