ima_crypto.c

  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(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(hash_algo_name[ima_hash_algo], 0, 0);
 75	if (IS_ERR(ima_shash_tfm)) {
 76		rc = PTR_ERR(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(hash_algo_name[algo], 0, 0);
102	if (IS_ERR(tfm)) {
103		rc = PTR_ERR(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(ima_algo_array[i].tfm)) {
163			if (algo == HASH_ALGO_SHA1) {
164				rc = PTR_ERR(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(HASH_ALGO_SHA1);
179			if (IS_ERR(ima_algo_array[ima_sha1_idx].tfm)) {
180				rc = PTR_ERR(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(ima_algo_array[i].tfm);
202	}
203	kfree(ima_algo_array);
204out:
205	crypto_free_shash(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((unsigned long)ptr, 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(hash_algo_name[algo], 0, 0);
295		if (!IS_ERR(tfm)) {
296			if (algo == ima_hash_algo)
297				ima_ahash_tfm = tfm;
298		} else {
299			rc = PTR_ERR(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);
343	ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
344				   CRYPTO_TFM_REQ_MAY_SLEEP,
345				   crypto_req_done, &wait);
346
347	rc = ahash_wait(crypto_ahash_init(req), &wait);
348	if (rc)
349		goto out1;
350
351	i_size = i_size_read(file_inode(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(i_size, &rbuf_size[0], 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(i_size - rbuf_size[0],
374					  &rbuf_size[1], 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(ahash_rc, &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, rbuf[active],
390					   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(ahash_rc, &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(ahash_rc, &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, sg, NULL, 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(ahash_rc, &wait);
422out3:
423	ima_free_pages(rbuf[0], rbuf_size[0]);
424	ima_free_pages(rbuf[1], rbuf_size[1]);
425out2:
426	if (!rc) {
427		ahash_request_set_crypt(req, NULL, hash->digest, 0);
428		rc = ahash_wait(crypto_ahash_final(req), &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(hash->algo);
441	if (IS_ERR(tfm))
442		return PTR_ERR(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(shash);
465	if (rc != 0)
466		return rc;
467
468	i_size = i_size_read(file_inode(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, 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(shash, rbuf, rbuf_len);
492		if (rc)
493			break;
494	}
495	kfree(rbuf);
496out:
497	if (!rc)
498		rc = crypto_shash_final(shash, 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(hash->algo);
508	if (IS_ERR(tfm))
509		return PTR_ERR(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(&file->f_path, flags, file->f_cred);
554		if (IS_ERR(f))
555			return PTR_ERR(f);
556
557		new_file_instance = true;
558	}
559
560	i_size = i_size_read(file_inode(f));
561
562	if (ima_ahash_minsize && i_size >= ima_ahash_minsize) {
563		rc = ima_calc_file_ahash(f, hash);
564		if (!rc)
565			goto out;
566	}
567
568	rc = ima_calc_file_shash(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(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(shash,
602						(const u8 *) &datalen_to_hash,
603						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(shash, data_to_hash, datalen);
612		if (rc)
613			break;
614	}
615
616	if (!rc)
617		rc = crypto_shash_final(shash, 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, 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, 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);
674	ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
675				   CRYPTO_TFM_REQ_MAY_SLEEP,
676				   crypto_req_done, &wait);
677
678	rc = ahash_wait(crypto_ahash_init(req), &wait);
679	if (rc)
680		goto out;
681
682	sg_init_one(&sg, buf, len);
683	ahash_request_set_crypt(req, &sg, NULL, len);
684
685	ahash_rc = crypto_ahash_update(req);
686
687	/* wait for the update request to complete */
688	rc = ahash_wait(ahash_rc, &wait);
689	if (!rc) {
690		ahash_request_set_crypt(req, NULL, hash->digest, 0);
691		rc = ahash_wait(crypto_ahash_final(req), &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(hash->algo);
705	if (IS_ERR(tfm))
706		return PTR_ERR(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(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(shash, buf, len);
734		if (rc)
735			break;
736		buf += len;
737		size -= len;
738	}
739
740	if (!rc)
741		rc = crypto_shash_final(shash, 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(hash->algo);
752	if (IS_ERR(tfm))
753		return PTR_ERR(tfm);
754
755	rc = calc_buffer_shash_tfm(buf, 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(ima_tpm_chip, idx, 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(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(i, &d);
815		/* now accumulate with current aggregate */
816		rc = crypto_shash_update(shash, d.digest,
817					 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(i, &d);
830			rc = crypto_shash_update(shash, d.digest,
831						crypto_shash_digestsize(tfm));
832		}
833	}
834	if (!rc)
835		crypto_shash_final(shash, 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(hash->algo);
867	if (IS_ERR(tfm))
868		return PTR_ERR(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(hash->digest, alg_id, tfm);
873
874	ima_free_tfm(tfm);
875
876	return rc;
877}