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 	kfree(ima_algo_array);
209 out:
210 	crypto_free_shash(ima_shash_tfm);
211 	return rc;
212 }
213 
ima_free_tfm(struct crypto_shash * tfm)214 static 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  */
ima_alloc_pages(loff_t max_size,size_t * allocated_size,int last_warn)243 static 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, 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  */
ima_free_pages(void * ptr,size_t size)283 static void ima_free_pages(void *ptr, size_t size)
284 {
285 	if (!ptr)
286 		return;
287 	free_pages((unsigned long)ptr, get_order(size));
288 }
289 
ima_alloc_atfm(enum hash_algo algo)290 static 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(hash_algo_name[algo], 0, 0);
300 		if (!IS_ERR(tfm)) {
301 			if (algo == ima_hash_algo)
302 				ima_ahash_tfm = tfm;
303 		} else {
304 			rc = PTR_ERR(tfm);
305 			pr_err("Can not allocate %s (reason: %d)\n",
306 			       hash_algo_name[algo], rc);
307 		}
308 	}
309 	return tfm;
310 }
311 
ima_free_atfm(struct crypto_ahash * tfm)312 static void ima_free_atfm(struct crypto_ahash *tfm)
313 {
314 	if (tfm != ima_ahash_tfm)
315 		crypto_free_ahash(tfm);
316 }
317 
ahash_wait(int err,struct crypto_wait * wait)318 static 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 
ima_calc_file_hash_atfm(struct file * file,struct ima_digest_data * hash,struct crypto_ahash * tfm)329 static 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);
348 	ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
349 				   CRYPTO_TFM_REQ_MAY_SLEEP,
350 				   crypto_req_done, &wait);
351 
352 	rc = ahash_wait(crypto_ahash_init(req), &wait);
353 	if (rc)
354 		goto out1;
355 
356 	i_size = i_size_read(file_inode(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(i_size, &rbuf_size[0], 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(i_size - rbuf_size[0],
379 					  &rbuf_size[1], 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(ahash_rc, &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, rbuf[active],
395 					   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(ahash_rc, &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(ahash_rc, &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, sg, NULL, 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(ahash_rc, &wait);
427 out3:
428 	ima_free_pages(rbuf[0], rbuf_size[0]);
429 	ima_free_pages(rbuf[1], rbuf_size[1]);
430 out2:
431 	if (!rc) {
432 		ahash_request_set_crypt(req, NULL, hash->digest, 0);
433 		rc = ahash_wait(crypto_ahash_final(req), &wait);
434 	}
435 out1:
436 	ahash_request_free(req);
437 	return rc;
438 }
439 
ima_calc_file_ahash(struct file * file,struct ima_digest_data * hash)440 static 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(hash->algo);
446 	if (IS_ERR(tfm))
447 		return PTR_ERR(tfm);
448 
449 	rc = ima_calc_file_hash_atfm(file, hash, tfm);
450 
451 	ima_free_atfm(tfm);
452 
453 	return rc;
454 }
455 
ima_calc_file_hash_tfm(struct file * file,struct ima_digest_data * hash,struct crypto_shash * tfm)456 static 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(shash);
470 	if (rc != 0)
471 		return rc;
472 
473 	i_size = i_size_read(file_inode(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, 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(shash, rbuf, rbuf_len);
497 		if (rc)
498 			break;
499 	}
500 	kfree(rbuf);
501 out:
502 	if (!rc)
503 		rc = crypto_shash_final(shash, hash->digest);
504 	return rc;
505 }
506 
ima_calc_file_shash(struct file * file,struct ima_digest_data * hash)507 static 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(hash->algo);
513 	if (IS_ERR(tfm))
514 		return PTR_ERR(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  */
ima_calc_file_hash(struct file * file,struct ima_digest_data * hash)536 int 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(&file->f_path, flags, file->f_cred);
559 		if (IS_ERR(f))
560 			return PTR_ERR(f);
561 
562 		new_file_instance = true;
563 	}
564 
565 	i_size = i_size_read(file_inode(f));
566 
567 	if (ima_ahash_minsize && i_size >= ima_ahash_minsize) {
568 		rc = ima_calc_file_ahash(f, hash);
569 		if (!rc)
570 			goto out;
571 	}
572 
573 	rc = ima_calc_file_shash(f, hash);
574 out:
575 	if (new_file_instance)
576 		fput(f);
577 	return rc;
578 }
579 
580 /*
581  * Calculate the hash of template data
582  */
ima_calc_field_array_hash_tfm(struct ima_field_data * field_data,struct ima_template_entry * entry,int tfm_idx)583 static 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(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(shash,
607 						(const u8 *) &datalen_to_hash,
608 						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(shash, data_to_hash, datalen);
617 		if (rc)
618 			break;
619 	}
620 
621 	if (!rc)
622 		rc = crypto_shash_final(shash, entry->digests[tfm_idx].digest);
623 
624 	return rc;
625 }
626 
ima_calc_field_array_hash(struct ima_field_data * field_data,struct ima_template_entry * entry)627 int 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, 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, i);
657 		if (rc)
658 			return rc;
659 	}
660 	return rc;
661 }
662 
calc_buffer_ahash_atfm(const void * buf,loff_t len,struct ima_digest_data * hash,struct crypto_ahash * tfm)663 static 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);
679 	ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
680 				   CRYPTO_TFM_REQ_MAY_SLEEP,
681 				   crypto_req_done, &wait);
682 
683 	rc = ahash_wait(crypto_ahash_init(req), &wait);
684 	if (rc)
685 		goto out;
686 
687 	sg_init_one(&sg, buf, len);
688 	ahash_request_set_crypt(req, &sg, NULL, len);
689 
690 	ahash_rc = crypto_ahash_update(req);
691 
692 	/* wait for the update request to complete */
693 	rc = ahash_wait(ahash_rc, &wait);
694 	if (!rc) {
695 		ahash_request_set_crypt(req, NULL, hash->digest, 0);
696 		rc = ahash_wait(crypto_ahash_final(req), &wait);
697 	}
698 out:
699 	ahash_request_free(req);
700 	return rc;
701 }
702 
calc_buffer_ahash(const void * buf,loff_t len,struct ima_digest_data * hash)703 static 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(hash->algo);
710 	if (IS_ERR(tfm))
711 		return PTR_ERR(tfm);
712 
713 	rc = calc_buffer_ahash_atfm(buf, len, hash, tfm);
714 
715 	ima_free_atfm(tfm);
716 
717 	return rc;
718 }
719 
calc_buffer_shash_tfm(const void * buf,loff_t size,struct ima_digest_data * hash,struct crypto_shash * tfm)720 static 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(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(shash, buf, len);
739 		if (rc)
740 			break;
741 		buf += len;
742 		size -= len;
743 	}
744 
745 	if (!rc)
746 		rc = crypto_shash_final(shash, hash->digest);
747 	return rc;
748 }
749 
calc_buffer_shash(const void * buf,loff_t len,struct ima_digest_data * hash)750 static 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(hash->algo);
757 	if (IS_ERR(tfm))
758 		return PTR_ERR(tfm);
759 
760 	rc = calc_buffer_shash_tfm(buf, len, hash, tfm);
761 
762 	ima_free_tfm(tfm);
763 	return rc;
764 }
765 
ima_calc_buffer_hash(const void * buf,loff_t len,struct ima_digest_data * hash)766 int 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 
ima_pcrread(u32 idx,struct tpm_digest * d)780 static void ima_pcrread(u32 idx, struct tpm_digest *d)
781 {
782 	if (!ima_tpm_chip)
783 		return;
784 
785 	if (tpm_pcr_read(ima_tpm_chip, idx, 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  */
ima_calc_boot_aggregate_tfm(char * digest,u16 alg_id,struct crypto_shash * tfm)800 static 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(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(i, &d);
820 		/* now accumulate with current aggregate */
821 		rc = crypto_shash_update(shash, d.digest,
822 					 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(i, &d);
835 			rc = crypto_shash_update(shash, d.digest,
836 						crypto_shash_digestsize(tfm));
837 		}
838 	}
839 	if (!rc)
840 		crypto_shash_final(shash, digest);
841 	return rc;
842 }
843 
ima_calc_boot_aggregate(struct ima_digest_data * hash)844 int 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(hash->algo);
872 	if (IS_ERR(tfm))
873 		return PTR_ERR(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(hash->digest, alg_id, tfm);
878 
879 	ima_free_tfm(tfm);
880 
881 	return rc;
882 }
883