1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2005,2006,2007,2008 IBM Corporation
4  *
5  * Authors:
6  * Mimi Zohar <zohar@us.ibm.com>
7  * Kylene Hall <kjhall@us.ibm.com>
8  *
9  * File: ima_crypto.c
10  *	Calculates md5/sha1 file hash, template hash, boot-aggreate hash
11  */
12 
13 #include <linux/kernel.h>
14 #include <linux/moduleparam.h>
15 #include <linux/ratelimit.h>
16 #include <linux/file.h>
17 #include <linux/crypto.h>
18 #include <linux/scatterlist.h>
19 #include <linux/err.h>
20 #include <linux/slab.h>
21 #include <crypto/hash.h>
22 
23 #include "ima.h"
24 
25 /* minimum file size for ahash use */
26 static unsigned long ima_ahash_minsize;
27 module_param_named(ahash_minsize, ima_ahash_minsize, ulong, 0644);
28 MODULE_PARM_DESC(ahash_minsize, "Minimum file size for ahash use");
29 
30 /* default is 0 - 1 page. */
31 static int ima_maxorder;
32 static unsigned int ima_bufsize = PAGE_SIZE;
33 
34 static int param_set_bufsize(const char *val, const struct kernel_param *kp)
35 {
36 	unsigned long long size;
37 	int order;
38 
39 	size = memparse(val, NULL);
40 	order = get_order(size);
41 	if (order >= MAX_ORDER)
42 		return -EINVAL;
43 	ima_maxorder = order;
44 	ima_bufsize = PAGE_SIZE << order;
45 	return 0;
46 }
47 
48 static const struct kernel_param_ops param_ops_bufsize = {
49 	.set = param_set_bufsize,
50 	.get = param_get_uint,
51 };
52 #define param_check_bufsize(name, p) __param_check(name, p, unsigned int)
53 
54 module_param_named(ahash_bufsize, ima_bufsize, bufsize, 0644);
55 MODULE_PARM_DESC(ahash_bufsize, "Maximum ahash buffer size");
56 
57 static struct crypto_shash *ima_shash_tfm;
58 static struct crypto_ahash *ima_ahash_tfm;
59 
60 struct ima_algo_desc {
61 	struct crypto_shash *tfm;
62 	enum hash_algo algo;
63 };
64 
65 int ima_sha1_idx __ro_after_init;
66 int ima_hash_algo_idx __ro_after_init;
67 /*
68  * Additional number of slots reserved, as needed, for SHA1
69  * and IMA default algo.
70  */
71 int ima_extra_slots __ro_after_init;
72 
73 static struct ima_algo_desc *ima_algo_array;
74 
75 static int __init ima_init_ima_crypto(void)
76 {
77 	long rc;
78 
79 	ima_shash_tfm = crypto_alloc_shash(hash_algo_name[ima_hash_algo], 0, 0);
80 	if (IS_ERR(ima_shash_tfm)) {
81 		rc = PTR_ERR(ima_shash_tfm);
82 		pr_err("Can not allocate %s (reason: %ld)\n",
83 		       hash_algo_name[ima_hash_algo], rc);
84 		return rc;
85 	}
86 	pr_info("Allocated hash algorithm: %s\n",
87 		hash_algo_name[ima_hash_algo]);
88 	return 0;
89 }
90 
91 static struct crypto_shash *ima_alloc_tfm(enum hash_algo algo)
92 {
93 	struct crypto_shash *tfm = ima_shash_tfm;
94 	int rc, i;
95 
96 	if (algo < 0 || algo >= HASH_ALGO__LAST)
97 		algo = ima_hash_algo;
98 
99 	if (algo == ima_hash_algo)
100 		return tfm;
101 
102 	for (i = 0; i < NR_BANKS(ima_tpm_chip) + ima_extra_slots; i++)
103 		if (ima_algo_array[i].tfm && ima_algo_array[i].algo == algo)
104 			return ima_algo_array[i].tfm;
105 
106 	tfm = crypto_alloc_shash(hash_algo_name[algo], 0, 0);
107 	if (IS_ERR(tfm)) {
108 		rc = PTR_ERR(tfm);
109 		pr_err("Can not allocate %s (reason: %d)\n",
110 		       hash_algo_name[algo], rc);
111 	}
112 	return tfm;
113 }
114 
115 int __init ima_init_crypto(void)
116 {
117 	enum hash_algo algo;
118 	long rc;
119 	int i;
120 
121 	rc = ima_init_ima_crypto();
122 	if (rc)
123 		return rc;
124 
125 	ima_sha1_idx = -1;
126 	ima_hash_algo_idx = -1;
127 
128 	for (i = 0; i < NR_BANKS(ima_tpm_chip); i++) {
129 		algo = ima_tpm_chip->allocated_banks[i].crypto_id;
130 		if (algo == HASH_ALGO_SHA1)
131 			ima_sha1_idx = i;
132 
133 		if (algo == ima_hash_algo)
134 			ima_hash_algo_idx = i;
135 	}
136 
137 	if (ima_sha1_idx < 0) {
138 		ima_sha1_idx = NR_BANKS(ima_tpm_chip) + ima_extra_slots++;
139 		if (ima_hash_algo == HASH_ALGO_SHA1)
140 			ima_hash_algo_idx = ima_sha1_idx;
141 	}
142 
143 	if (ima_hash_algo_idx < 0)
144 		ima_hash_algo_idx = NR_BANKS(ima_tpm_chip) + ima_extra_slots++;
145 
146 	ima_algo_array = kcalloc(NR_BANKS(ima_tpm_chip) + ima_extra_slots,
147 				 sizeof(*ima_algo_array), GFP_KERNEL);
148 	if (!ima_algo_array) {
149 		rc = -ENOMEM;
150 		goto out;
151 	}
152 
153 	for (i = 0; i < NR_BANKS(ima_tpm_chip); i++) {
154 		algo = ima_tpm_chip->allocated_banks[i].crypto_id;
155 		ima_algo_array[i].algo = algo;
156 
157 		/* unknown TPM algorithm */
158 		if (algo == HASH_ALGO__LAST)
159 			continue;
160 
161 		if (algo == ima_hash_algo) {
162 			ima_algo_array[i].tfm = ima_shash_tfm;
163 			continue;
164 		}
165 
166 		ima_algo_array[i].tfm = ima_alloc_tfm(algo);
167 		if (IS_ERR(ima_algo_array[i].tfm)) {
168 			if (algo == HASH_ALGO_SHA1) {
169 				rc = PTR_ERR(ima_algo_array[i].tfm);
170 				ima_algo_array[i].tfm = NULL;
171 				goto out_array;
172 			}
173 
174 			ima_algo_array[i].tfm = NULL;
175 		}
176 	}
177 
178 	if (ima_sha1_idx >= NR_BANKS(ima_tpm_chip)) {
179 		if (ima_hash_algo == HASH_ALGO_SHA1) {
180 			ima_algo_array[ima_sha1_idx].tfm = ima_shash_tfm;
181 		} else {
182 			ima_algo_array[ima_sha1_idx].tfm =
183 						ima_alloc_tfm(HASH_ALGO_SHA1);
184 			if (IS_ERR(ima_algo_array[ima_sha1_idx].tfm)) {
185 				rc = PTR_ERR(ima_algo_array[ima_sha1_idx].tfm);
186 				goto out_array;
187 			}
188 		}
189 
190 		ima_algo_array[ima_sha1_idx].algo = HASH_ALGO_SHA1;
191 	}
192 
193 	if (ima_hash_algo_idx >= NR_BANKS(ima_tpm_chip) &&
194 	    ima_hash_algo_idx != ima_sha1_idx) {
195 		ima_algo_array[ima_hash_algo_idx].tfm = ima_shash_tfm;
196 		ima_algo_array[ima_hash_algo_idx].algo = ima_hash_algo;
197 	}
198 
199 	return 0;
200 out_array:
201 	for (i = 0; i < NR_BANKS(ima_tpm_chip) + ima_extra_slots; i++) {
202 		if (!ima_algo_array[i].tfm ||
203 		    ima_algo_array[i].tfm == ima_shash_tfm)
204 			continue;
205 
206 		crypto_free_shash(ima_algo_array[i].tfm);
207 	}
208 out:
209 	crypto_free_shash(ima_shash_tfm);
210 	return rc;
211 }
212 
213 static void ima_free_tfm(struct crypto_shash *tfm)
214 {
215 	int i;
216 
217 	if (tfm == ima_shash_tfm)
218 		return;
219 
220 	for (i = 0; i < NR_BANKS(ima_tpm_chip) + ima_extra_slots; i++)
221 		if (ima_algo_array[i].tfm == tfm)
222 			return;
223 
224 	crypto_free_shash(tfm);
225 }
226 
227 /**
228  * ima_alloc_pages() - Allocate contiguous pages.
229  * @max_size:       Maximum amount of memory to allocate.
230  * @allocated_size: Returned size of actual allocation.
231  * @last_warn:      Should the min_size allocation warn or not.
232  *
233  * Tries to do opportunistic allocation for memory first trying to allocate
234  * max_size amount of memory and then splitting that until zero order is
235  * reached. Allocation is tried without generating allocation warnings unless
236  * last_warn is set. Last_warn set affects only last allocation of zero order.
237  *
238  * By default, ima_maxorder is 0 and it is equivalent to kmalloc(GFP_KERNEL)
239  *
240  * Return pointer to allocated memory, or NULL on failure.
241  */
242 static void *ima_alloc_pages(loff_t max_size, size_t *allocated_size,
243 			     int last_warn)
244 {
245 	void *ptr;
246 	int order = ima_maxorder;
247 	gfp_t gfp_mask = __GFP_RECLAIM | __GFP_NOWARN | __GFP_NORETRY;
248 
249 	if (order)
250 		order = min(get_order(max_size), order);
251 
252 	for (; order; order--) {
253 		ptr = (void *)__get_free_pages(gfp_mask, order);
254 		if (ptr) {
255 			*allocated_size = PAGE_SIZE << order;
256 			return ptr;
257 		}
258 	}
259 
260 	/* order is zero - one page */
261 
262 	gfp_mask = GFP_KERNEL;
263 
264 	if (!last_warn)
265 		gfp_mask |= __GFP_NOWARN;
266 
267 	ptr = (void *)__get_free_pages(gfp_mask, 0);
268 	if (ptr) {
269 		*allocated_size = PAGE_SIZE;
270 		return ptr;
271 	}
272 
273 	*allocated_size = 0;
274 	return NULL;
275 }
276 
277 /**
278  * ima_free_pages() - Free pages allocated by ima_alloc_pages().
279  * @ptr:  Pointer to allocated pages.
280  * @size: Size of allocated buffer.
281  */
282 static void ima_free_pages(void *ptr, size_t size)
283 {
284 	if (!ptr)
285 		return;
286 	free_pages((unsigned long)ptr, get_order(size));
287 }
288 
289 static struct crypto_ahash *ima_alloc_atfm(enum hash_algo algo)
290 {
291 	struct crypto_ahash *tfm = ima_ahash_tfm;
292 	int rc;
293 
294 	if (algo < 0 || algo >= HASH_ALGO__LAST)
295 		algo = ima_hash_algo;
296 
297 	if (algo != ima_hash_algo || !tfm) {
298 		tfm = crypto_alloc_ahash(hash_algo_name[algo], 0, 0);
299 		if (!IS_ERR(tfm)) {
300 			if (algo == ima_hash_algo)
301 				ima_ahash_tfm = tfm;
302 		} else {
303 			rc = PTR_ERR(tfm);
304 			pr_err("Can not allocate %s (reason: %d)\n",
305 			       hash_algo_name[algo], rc);
306 		}
307 	}
308 	return tfm;
309 }
310 
311 static void ima_free_atfm(struct crypto_ahash *tfm)
312 {
313 	if (tfm != ima_ahash_tfm)
314 		crypto_free_ahash(tfm);
315 }
316 
317 static inline int ahash_wait(int err, struct crypto_wait *wait)
318 {
319 
320 	err = crypto_wait_req(err, wait);
321 
322 	if (err)
323 		pr_crit_ratelimited("ahash calculation failed: err: %d\n", err);
324 
325 	return err;
326 }
327 
328 static int ima_calc_file_hash_atfm(struct file *file,
329 				   struct ima_digest_data *hash,
330 				   struct crypto_ahash *tfm)
331 {
332 	loff_t i_size, offset;
333 	char *rbuf[2] = { NULL, };
334 	int rc, rbuf_len, active = 0, ahash_rc = 0;
335 	struct ahash_request *req;
336 	struct scatterlist sg[1];
337 	struct crypto_wait wait;
338 	size_t rbuf_size[2];
339 
340 	hash->length = crypto_ahash_digestsize(tfm);
341 
342 	req = ahash_request_alloc(tfm, GFP_KERNEL);
343 	if (!req)
344 		return -ENOMEM;
345 
346 	crypto_init_wait(&wait);
347 	ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
348 				   CRYPTO_TFM_REQ_MAY_SLEEP,
349 				   crypto_req_done, &wait);
350 
351 	rc = ahash_wait(crypto_ahash_init(req), &wait);
352 	if (rc)
353 		goto out1;
354 
355 	i_size = i_size_read(file_inode(file));
356 
357 	if (i_size == 0)
358 		goto out2;
359 
360 	/*
361 	 * Try to allocate maximum size of memory.
362 	 * Fail if even a single page cannot be allocated.
363 	 */
364 	rbuf[0] = ima_alloc_pages(i_size, &rbuf_size[0], 1);
365 	if (!rbuf[0]) {
366 		rc = -ENOMEM;
367 		goto out1;
368 	}
369 
370 	/* Only allocate one buffer if that is enough. */
371 	if (i_size > rbuf_size[0]) {
372 		/*
373 		 * Try to allocate secondary buffer. If that fails fallback to
374 		 * using single buffering. Use previous memory allocation size
375 		 * as baseline for possible allocation size.
376 		 */
377 		rbuf[1] = ima_alloc_pages(i_size - rbuf_size[0],
378 					  &rbuf_size[1], 0);
379 	}
380 
381 	for (offset = 0; offset < i_size; offset += rbuf_len) {
382 		if (!rbuf[1] && offset) {
383 			/* Not using two buffers, and it is not the first
384 			 * read/request, wait for the completion of the
385 			 * previous ahash_update() request.
386 			 */
387 			rc = ahash_wait(ahash_rc, &wait);
388 			if (rc)
389 				goto out3;
390 		}
391 		/* read buffer */
392 		rbuf_len = min_t(loff_t, i_size - offset, rbuf_size[active]);
393 		rc = integrity_kernel_read(file, offset, rbuf[active],
394 					   rbuf_len);
395 		if (rc != rbuf_len) {
396 			if (rc >= 0)
397 				rc = -EINVAL;
398 			/*
399 			 * Forward current rc, do not overwrite with return value
400 			 * from ahash_wait()
401 			 */
402 			ahash_wait(ahash_rc, &wait);
403 			goto out3;
404 		}
405 
406 		if (rbuf[1] && offset) {
407 			/* Using two buffers, and it is not the first
408 			 * read/request, wait for the completion of the
409 			 * previous ahash_update() request.
410 			 */
411 			rc = ahash_wait(ahash_rc, &wait);
412 			if (rc)
413 				goto out3;
414 		}
415 
416 		sg_init_one(&sg[0], rbuf[active], rbuf_len);
417 		ahash_request_set_crypt(req, sg, NULL, rbuf_len);
418 
419 		ahash_rc = crypto_ahash_update(req);
420 
421 		if (rbuf[1])
422 			active = !active; /* swap buffers, if we use two */
423 	}
424 	/* wait for the last update request to complete */
425 	rc = ahash_wait(ahash_rc, &wait);
426 out3:
427 	ima_free_pages(rbuf[0], rbuf_size[0]);
428 	ima_free_pages(rbuf[1], rbuf_size[1]);
429 out2:
430 	if (!rc) {
431 		ahash_request_set_crypt(req, NULL, hash->digest, 0);
432 		rc = ahash_wait(crypto_ahash_final(req), &wait);
433 	}
434 out1:
435 	ahash_request_free(req);
436 	return rc;
437 }
438 
439 static int ima_calc_file_ahash(struct file *file, struct ima_digest_data *hash)
440 {
441 	struct crypto_ahash *tfm;
442 	int rc;
443 
444 	tfm = ima_alloc_atfm(hash->algo);
445 	if (IS_ERR(tfm))
446 		return PTR_ERR(tfm);
447 
448 	rc = ima_calc_file_hash_atfm(file, hash, tfm);
449 
450 	ima_free_atfm(tfm);
451 
452 	return rc;
453 }
454 
455 static int ima_calc_file_hash_tfm(struct file *file,
456 				  struct ima_digest_data *hash,
457 				  struct crypto_shash *tfm)
458 {
459 	loff_t i_size, offset = 0;
460 	char *rbuf;
461 	int rc;
462 	SHASH_DESC_ON_STACK(shash, tfm);
463 
464 	shash->tfm = tfm;
465 
466 	hash->length = crypto_shash_digestsize(tfm);
467 
468 	rc = crypto_shash_init(shash);
469 	if (rc != 0)
470 		return rc;
471 
472 	i_size = i_size_read(file_inode(file));
473 
474 	if (i_size == 0)
475 		goto out;
476 
477 	rbuf = kzalloc(PAGE_SIZE, GFP_KERNEL);
478 	if (!rbuf)
479 		return -ENOMEM;
480 
481 	while (offset < i_size) {
482 		int rbuf_len;
483 
484 		rbuf_len = integrity_kernel_read(file, offset, rbuf, PAGE_SIZE);
485 		if (rbuf_len < 0) {
486 			rc = rbuf_len;
487 			break;
488 		}
489 		if (rbuf_len == 0) {	/* unexpected EOF */
490 			rc = -EINVAL;
491 			break;
492 		}
493 		offset += rbuf_len;
494 
495 		rc = crypto_shash_update(shash, rbuf, rbuf_len);
496 		if (rc)
497 			break;
498 	}
499 	kfree(rbuf);
500 out:
501 	if (!rc)
502 		rc = crypto_shash_final(shash, hash->digest);
503 	return rc;
504 }
505 
506 static int ima_calc_file_shash(struct file *file, struct ima_digest_data *hash)
507 {
508 	struct crypto_shash *tfm;
509 	int rc;
510 
511 	tfm = ima_alloc_tfm(hash->algo);
512 	if (IS_ERR(tfm))
513 		return PTR_ERR(tfm);
514 
515 	rc = ima_calc_file_hash_tfm(file, hash, tfm);
516 
517 	ima_free_tfm(tfm);
518 
519 	return rc;
520 }
521 
522 /*
523  * ima_calc_file_hash - calculate file hash
524  *
525  * Asynchronous hash (ahash) allows using HW acceleration for calculating
526  * a hash. ahash performance varies for different data sizes on different
527  * crypto accelerators. shash performance might be better for smaller files.
528  * The 'ima.ahash_minsize' module parameter allows specifying the best
529  * minimum file size for using ahash on the system.
530  *
531  * If the ima.ahash_minsize parameter is not specified, this function uses
532  * shash for the hash calculation.  If ahash fails, it falls back to using
533  * shash.
534  */
535 int ima_calc_file_hash(struct file *file, struct ima_digest_data *hash)
536 {
537 	loff_t i_size;
538 	int rc;
539 	struct file *f = file;
540 	bool new_file_instance = false, 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  */
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 
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 
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 
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 
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 
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 
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 
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  */
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 	}
833 	/*
834 	 * Extend cumulative digest over TPM registers 8-9, which contain
835 	 * measurement for the kernel command line (reg. 8) and image (reg. 9)
836 	 * in a typical PCR allocation. Registers 8-9 are only included in
837 	 * non-SHA1 boot_aggregate digests to avoid ambiguity.
838 	 */
839 	if (alg_id != TPM_ALG_SHA1) {
840 		for (i = TPM_PCR8; i < TPM_PCR10; i++) {
841 			ima_pcrread(i, &d);
842 			rc = crypto_shash_update(shash, d.digest,
843 						crypto_shash_digestsize(tfm));
844 		}
845 	}
846 	if (!rc)
847 		crypto_shash_final(shash, digest);
848 	return rc;
849 }
850 
851 int ima_calc_boot_aggregate(struct ima_digest_data *hash)
852 {
853 	struct crypto_shash *tfm;
854 	u16 crypto_id, alg_id;
855 	int rc, i, bank_idx = -1;
856 
857 	for (i = 0; i < ima_tpm_chip->nr_allocated_banks; i++) {
858 		crypto_id = ima_tpm_chip->allocated_banks[i].crypto_id;
859 		if (crypto_id == hash->algo) {
860 			bank_idx = i;
861 			break;
862 		}
863 
864 		if (crypto_id == HASH_ALGO_SHA256)
865 			bank_idx = i;
866 
867 		if (bank_idx == -1 && crypto_id == HASH_ALGO_SHA1)
868 			bank_idx = i;
869 	}
870 
871 	if (bank_idx == -1) {
872 		pr_err("No suitable TPM algorithm for boot aggregate\n");
873 		return 0;
874 	}
875 
876 	hash->algo = ima_tpm_chip->allocated_banks[bank_idx].crypto_id;
877 
878 	tfm = ima_alloc_tfm(hash->algo);
879 	if (IS_ERR(tfm))
880 		return PTR_ERR(tfm);
881 
882 	hash->length = crypto_shash_digestsize(tfm);
883 	alg_id = ima_tpm_chip->allocated_banks[bank_idx].alg_id;
884 	rc = ima_calc_boot_aggregate_tfm(hash->digest, alg_id, tfm);
885 
886 	ima_free_tfm(tfm);
887 
888 	return rc;
889 }
890