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
param_set_bufsize(const char * val,const struct kernel_param * kp)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
ima_init_ima_crypto(void)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
ima_alloc_tfm(enum hash_algo algo)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
ima_init_crypto(void)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
ima_free_tfm(struct crypto_shash * tfm)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 */
ima_alloc_pages(loff_t max_size,size_t * allocated_size,int last_warn)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 */
ima_free_pages(void * ptr,size_t size)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
ima_alloc_atfm(enum hash_algo algo)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
ima_free_atfm(struct crypto_ahash * tfm)311 static void ima_free_atfm(struct crypto_ahash *tfm)
312 {
313 if (tfm != ima_ahash_tfm)
314 crypto_free_ahash(tfm);
315 }
316
ahash_wait(int err,struct crypto_wait * wait)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
ima_calc_file_hash_atfm(struct file * file,struct ima_digest_data * hash,struct crypto_ahash * tfm)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
ima_calc_file_ahash(struct file * file,struct ima_digest_data * hash)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
ima_calc_file_hash_tfm(struct file * file,struct ima_digest_data * hash,struct crypto_shash * tfm)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
ima_calc_file_shash(struct file * file,struct ima_digest_data * hash)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 */
ima_calc_file_hash(struct file * file,struct ima_digest_data * hash)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, 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);
581 out:
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 */
ima_calc_field_array_hash_tfm(struct ima_field_data * field_data,struct ima_template_entry * entry,int tfm_idx)592 static 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
ima_calc_field_array_hash(struct ima_field_data * field_data,struct ima_template_entry * entry)636 int 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
calc_buffer_ahash_atfm(const void * buf,loff_t len,struct ima_digest_data * hash,struct crypto_ahash * tfm)672 static 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 }
707 out:
708 ahash_request_free(req);
709 return rc;
710 }
711
calc_buffer_ahash(const void * buf,loff_t len,struct ima_digest_data * hash)712 static 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
calc_buffer_shash_tfm(const void * buf,loff_t size,struct ima_digest_data * hash,struct crypto_shash * tfm)729 static 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
calc_buffer_shash(const void * buf,loff_t len,struct ima_digest_data * hash)759 static 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
ima_calc_buffer_hash(const void * buf,loff_t len,struct ima_digest_data * hash)775 int 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
ima_pcrread(u32 idx,struct tpm_digest * d)789 static 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 */
ima_calc_boot_aggregate_tfm(char * digest,u16 alg_id,struct crypto_shash * tfm)809 static 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
ima_calc_boot_aggregate(struct ima_digest_data * hash)853 int 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
