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
60int ima_sha1_idx __ro_after_init;
61int ima_hash_algo_idx __ro_after_init;
62/*
63 * Additional number of slots reserved, as needed, for SHA1
64 * and IMA default algo.
65 */
66int ima_extra_slots __ro_after_init;
67
68struct ima_algo_desc *ima_algo_array __ro_after_init;
69
70static int __init ima_init_ima_crypto(void)
71{
72 long rc;
73
74 ima_shash_tfm = crypto_alloc_shash(alg_name: hash_algo_name[ima_hash_algo], type: 0, mask: 0);
75 if (IS_ERR(ptr: ima_shash_tfm)) {
76 rc = PTR_ERR(ptr: 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
86static 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(alg_name: hash_algo_name[algo], type: 0, mask: 0);
102 if (IS_ERR(ptr: tfm)) {
103 rc = PTR_ERR(ptr: tfm);
104 pr_err("Can not allocate %s (reason: %d)\n",
105 hash_algo_name[algo], rc);
106 }
107 return tfm;
108}
109
110int __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(ptr: ima_algo_array[i].tfm)) {
163 if (algo == HASH_ALGO_SHA1) {
164 rc = PTR_ERR(ptr: 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(algo: HASH_ALGO_SHA1);
179 if (IS_ERR(ptr: ima_algo_array[ima_sha1_idx].tfm)) {
180 rc = PTR_ERR(ptr: 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;
195out_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(tfm: ima_algo_array[i].tfm);
202 }
203 kfree(objp: ima_algo_array);
204out:
205 crypto_free_shash(tfm: ima_shash_tfm);
206 return rc;
207}
208
209static 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 */
238static 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 */
278static void ima_free_pages(void *ptr, size_t size)
279{
280 if (!ptr)
281 return;
282 free_pages(addr: (unsigned long)ptr, order: get_order(size));
283}
284
285static 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(alg_name: hash_algo_name[algo], type: 0, mask: 0);
295 if (!IS_ERR(ptr: tfm)) {
296 if (algo == ima_hash_algo)
297 ima_ahash_tfm = tfm;
298 } else {
299 rc = PTR_ERR(ptr: tfm);
300 pr_err("Can not allocate %s (reason: %d)\n",
301 hash_algo_name[algo], rc);
302 }
303 }
304 return tfm;
305}
306
307static void ima_free_atfm(struct crypto_ahash *tfm)
308{
309 if (tfm != ima_ahash_tfm)
310 crypto_free_ahash(tfm);
311}
312
313static 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
324static 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: &wait);
343 ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
344 CRYPTO_TFM_REQ_MAY_SLEEP,
345 compl: crypto_req_done, data: &wait);
346
347 rc = ahash_wait(err: crypto_ahash_init(req), wait: &wait);
348 if (rc)
349 goto out1;
350
351 i_size = i_size_read(inode: file_inode(f: 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(max_size: i_size, allocated_size: &rbuf_size[0], last_warn: 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(max_size: i_size - rbuf_size[0],
374 allocated_size: &rbuf_size[1], last_warn: 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(err: ahash_rc, wait: &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, addr: rbuf[active],
390 count: 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(err: ahash_rc, wait: &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(err: ahash_rc, wait: &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, src: sg, NULL, nbytes: 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(err: ahash_rc, wait: &wait);
422out3:
423 ima_free_pages(ptr: rbuf[0], size: rbuf_size[0]);
424 ima_free_pages(ptr: rbuf[1], size: rbuf_size[1]);
425out2:
426 if (!rc) {
427 ahash_request_set_crypt(req, NULL, result: hash->digest, nbytes: 0);
428 rc = ahash_wait(err: crypto_ahash_final(req), wait: &wait);
429 }
430out1:
431 ahash_request_free(req);
432 return rc;
433}
434
435static 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(algo: hash->algo);
441 if (IS_ERR(ptr: tfm))
442 return PTR_ERR(ptr: tfm);
443
444 rc = ima_calc_file_hash_atfm(file, hash, tfm);
445
446 ima_free_atfm(tfm);
447
448 return rc;
449}
450
451static 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(desc: shash);
465 if (rc != 0)
466 return rc;
467
468 i_size = i_size_read(inode: file_inode(f: 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, addr: 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(desc: shash, data: rbuf, len: rbuf_len);
492 if (rc)
493 break;
494 }
495 kfree(objp: rbuf);
496out:
497 if (!rc)
498 rc = crypto_shash_final(desc: shash, out: hash->digest);
499 return rc;
500}
501
502static 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(algo: hash->algo);
508 if (IS_ERR(ptr: tfm))
509 return PTR_ERR(ptr: 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 */
531int 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(path: &file->f_path, flags, creds: file->f_cred);
554 if (IS_ERR(ptr: f))
555 return PTR_ERR(ptr: f);
556
557 new_file_instance = true;
558 }
559
560 i_size = i_size_read(inode: file_inode(f));
561
562 if (ima_ahash_minsize && i_size >= ima_ahash_minsize) {
563 rc = ima_calc_file_ahash(file: f, hash);
564 if (!rc)
565 goto out;
566 }
567
568 rc = ima_calc_file_shash(file: f, hash);
569out:
570 if (new_file_instance)
571 fput(f);
572 return rc;
573}
574
575/*
576 * Calculate the hash of template data
577 */
578static 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(desc: 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(desc: shash,
602 data: (const u8 *) &datalen_to_hash,
603 len: 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(desc: shash, data: data_to_hash, len: datalen);
612 if (rc)
613 break;
614 }
615
616 if (!rc)
617 rc = crypto_shash_final(desc: shash, out: entry->digests[tfm_idx].digest);
618
619 return rc;
620}
621
622int 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, tfm_idx: 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, tfm_idx: i);
652 if (rc)
653 return rc;
654 }
655 return rc;
656}
657
658static 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: &wait);
674 ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
675 CRYPTO_TFM_REQ_MAY_SLEEP,
676 compl: crypto_req_done, data: &wait);
677
678 rc = ahash_wait(err: crypto_ahash_init(req), wait: &wait);
679 if (rc)
680 goto out;
681
682 sg_init_one(&sg, buf, len);
683 ahash_request_set_crypt(req, src: &sg, NULL, nbytes: len);
684
685 ahash_rc = crypto_ahash_update(req);
686
687 /* wait for the update request to complete */
688 rc = ahash_wait(err: ahash_rc, wait: &wait);
689 if (!rc) {
690 ahash_request_set_crypt(req, NULL, result: hash->digest, nbytes: 0);
691 rc = ahash_wait(err: crypto_ahash_final(req), wait: &wait);
692 }
693out:
694 ahash_request_free(req);
695 return rc;
696}
697
698static 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(algo: hash->algo);
705 if (IS_ERR(ptr: tfm))
706 return PTR_ERR(ptr: tfm);
707
708 rc = calc_buffer_ahash_atfm(buf, len, hash, tfm);
709
710 ima_free_atfm(tfm);
711
712 return rc;
713}
714
715static 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(desc: 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(desc: shash, data: buf, len);
734 if (rc)
735 break;
736 buf += len;
737 size -= len;
738 }
739
740 if (!rc)
741 rc = crypto_shash_final(desc: shash, out: hash->digest);
742 return rc;
743}
744
745static 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(algo: hash->algo);
752 if (IS_ERR(ptr: tfm))
753 return PTR_ERR(ptr: tfm);
754
755 rc = calc_buffer_shash_tfm(buf, size: len, hash, tfm);
756
757 ima_free_tfm(tfm);
758 return rc;
759}
760
761int 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
775static void ima_pcrread(u32 idx, struct tpm_digest *d)
776{
777 if (!ima_tpm_chip)
778 return;
779
780 if (tpm_pcr_read(chip: ima_tpm_chip, pcr_idx: idx, digest: 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 */
795static 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(desc: 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(idx: i, d: &d);
815 /* now accumulate with current aggregate */
816 rc = crypto_shash_update(desc: shash, data: d.digest,
817 len: 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(idx: i, d: &d);
830 rc = crypto_shash_update(desc: shash, data: d.digest,
831 len: crypto_shash_digestsize(tfm));
832 }
833 }
834 if (!rc)
835 crypto_shash_final(desc: shash, out: digest);
836 return rc;
837}
838
839int 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(algo: hash->algo);
867 if (IS_ERR(ptr: tfm))
868 return PTR_ERR(ptr: 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(digest: hash->digest, alg_id, tfm);
873
874 ima_free_tfm(tfm);
875
876 return rc;
877}
878

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