Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost
[linux-2.6-microblaze.git] / security / integrity / ima / 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 */
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;
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                         return PTR_ERR(f);
560
561                 new_file_instance = true;
562         }
563
564         i_size = i_size_read(file_inode(f));
565
566         if (ima_ahash_minsize && i_size >= ima_ahash_minsize) {
567                 rc = ima_calc_file_ahash(f, hash);
568                 if (!rc)
569                         goto out;
570         }
571
572         rc = ima_calc_file_shash(f, hash);
573 out:
574         if (new_file_instance)
575                 fput(f);
576         return rc;
577 }
578
579 /*
580  * Calculate the hash of template data
581  */
582 static int ima_calc_field_array_hash_tfm(struct ima_field_data *field_data,
583                                          struct ima_template_entry *entry,
584                                          int tfm_idx)
585 {
586         SHASH_DESC_ON_STACK(shash, ima_algo_array[tfm_idx].tfm);
587         struct ima_template_desc *td = entry->template_desc;
588         int num_fields = entry->template_desc->num_fields;
589         int rc, i;
590
591         shash->tfm = ima_algo_array[tfm_idx].tfm;
592
593         rc = crypto_shash_init(shash);
594         if (rc != 0)
595                 return rc;
596
597         for (i = 0; i < num_fields; i++) {
598                 u8 buffer[IMA_EVENT_NAME_LEN_MAX + 1] = { 0 };
599                 u8 *data_to_hash = field_data[i].data;
600                 u32 datalen = field_data[i].len;
601                 u32 datalen_to_hash =
602                     !ima_canonical_fmt ? datalen : cpu_to_le32(datalen);
603
604                 if (strcmp(td->name, IMA_TEMPLATE_IMA_NAME) != 0) {
605                         rc = crypto_shash_update(shash,
606                                                 (const u8 *) &datalen_to_hash,
607                                                 sizeof(datalen_to_hash));
608                         if (rc)
609                                 break;
610                 } else if (strcmp(td->fields[i]->field_id, "n") == 0) {
611                         memcpy(buffer, data_to_hash, datalen);
612                         data_to_hash = buffer;
613                         datalen = IMA_EVENT_NAME_LEN_MAX + 1;
614                 }
615                 rc = crypto_shash_update(shash, data_to_hash, datalen);
616                 if (rc)
617                         break;
618         }
619
620         if (!rc)
621                 rc = crypto_shash_final(shash, entry->digests[tfm_idx].digest);
622
623         return rc;
624 }
625
626 int ima_calc_field_array_hash(struct ima_field_data *field_data,
627                               struct ima_template_entry *entry)
628 {
629         u16 alg_id;
630         int rc, i;
631
632         rc = ima_calc_field_array_hash_tfm(field_data, entry, ima_sha1_idx);
633         if (rc)
634                 return rc;
635
636         entry->digests[ima_sha1_idx].alg_id = TPM_ALG_SHA1;
637
638         for (i = 0; i < NR_BANKS(ima_tpm_chip) + ima_extra_slots; i++) {
639                 if (i == ima_sha1_idx)
640                         continue;
641
642                 if (i < NR_BANKS(ima_tpm_chip)) {
643                         alg_id = ima_tpm_chip->allocated_banks[i].alg_id;
644                         entry->digests[i].alg_id = alg_id;
645                 }
646
647                 /* for unmapped TPM algorithms digest is still a padded SHA1 */
648                 if (!ima_algo_array[i].tfm) {
649                         memcpy(entry->digests[i].digest,
650                                entry->digests[ima_sha1_idx].digest,
651                                TPM_DIGEST_SIZE);
652                         continue;
653                 }
654
655                 rc = ima_calc_field_array_hash_tfm(field_data, entry, i);
656                 if (rc)
657                         return rc;
658         }
659         return rc;
660 }
661
662 static int calc_buffer_ahash_atfm(const void *buf, loff_t len,
663                                   struct ima_digest_data *hash,
664                                   struct crypto_ahash *tfm)
665 {
666         struct ahash_request *req;
667         struct scatterlist sg;
668         struct crypto_wait wait;
669         int rc, ahash_rc = 0;
670
671         hash->length = crypto_ahash_digestsize(tfm);
672
673         req = ahash_request_alloc(tfm, GFP_KERNEL);
674         if (!req)
675                 return -ENOMEM;
676
677         crypto_init_wait(&wait);
678         ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
679                                    CRYPTO_TFM_REQ_MAY_SLEEP,
680                                    crypto_req_done, &wait);
681
682         rc = ahash_wait(crypto_ahash_init(req), &wait);
683         if (rc)
684                 goto out;
685
686         sg_init_one(&sg, buf, len);
687         ahash_request_set_crypt(req, &sg, NULL, len);
688
689         ahash_rc = crypto_ahash_update(req);
690
691         /* wait for the update request to complete */
692         rc = ahash_wait(ahash_rc, &wait);
693         if (!rc) {
694                 ahash_request_set_crypt(req, NULL, hash->digest, 0);
695                 rc = ahash_wait(crypto_ahash_final(req), &wait);
696         }
697 out:
698         ahash_request_free(req);
699         return rc;
700 }
701
702 static int calc_buffer_ahash(const void *buf, loff_t len,
703                              struct ima_digest_data *hash)
704 {
705         struct crypto_ahash *tfm;
706         int rc;
707
708         tfm = ima_alloc_atfm(hash->algo);
709         if (IS_ERR(tfm))
710                 return PTR_ERR(tfm);
711
712         rc = calc_buffer_ahash_atfm(buf, len, hash, tfm);
713
714         ima_free_atfm(tfm);
715
716         return rc;
717 }
718
719 static int calc_buffer_shash_tfm(const void *buf, loff_t size,
720                                 struct ima_digest_data *hash,
721                                 struct crypto_shash *tfm)
722 {
723         SHASH_DESC_ON_STACK(shash, tfm);
724         unsigned int len;
725         int rc;
726
727         shash->tfm = tfm;
728
729         hash->length = crypto_shash_digestsize(tfm);
730
731         rc = crypto_shash_init(shash);
732         if (rc != 0)
733                 return rc;
734
735         while (size) {
736                 len = size < PAGE_SIZE ? size : PAGE_SIZE;
737                 rc = crypto_shash_update(shash, buf, len);
738                 if (rc)
739                         break;
740                 buf += len;
741                 size -= len;
742         }
743
744         if (!rc)
745                 rc = crypto_shash_final(shash, hash->digest);
746         return rc;
747 }
748
749 static int calc_buffer_shash(const void *buf, loff_t len,
750                              struct ima_digest_data *hash)
751 {
752         struct crypto_shash *tfm;
753         int rc;
754
755         tfm = ima_alloc_tfm(hash->algo);
756         if (IS_ERR(tfm))
757                 return PTR_ERR(tfm);
758
759         rc = calc_buffer_shash_tfm(buf, len, hash, tfm);
760
761         ima_free_tfm(tfm);
762         return rc;
763 }
764
765 int ima_calc_buffer_hash(const void *buf, loff_t len,
766                          struct ima_digest_data *hash)
767 {
768         int rc;
769
770         if (ima_ahash_minsize && len >= ima_ahash_minsize) {
771                 rc = calc_buffer_ahash(buf, len, hash);
772                 if (!rc)
773                         return 0;
774         }
775
776         return calc_buffer_shash(buf, len, hash);
777 }
778
779 static void ima_pcrread(u32 idx, struct tpm_digest *d)
780 {
781         if (!ima_tpm_chip)
782                 return;
783
784         if (tpm_pcr_read(ima_tpm_chip, idx, d) != 0)
785                 pr_err("Error Communicating to TPM chip\n");
786 }
787
788 /*
789  * The boot_aggregate is a cumulative hash over TPM registers 0 - 7.  With
790  * TPM 1.2 the boot_aggregate was based on reading the SHA1 PCRs, but with
791  * TPM 2.0 hash agility, TPM chips could support multiple TPM PCR banks,
792  * allowing firmware to configure and enable different banks.
793  *
794  * Knowing which TPM bank is read to calculate the boot_aggregate digest
795  * needs to be conveyed to a verifier.  For this reason, use the same
796  * hash algorithm for reading the TPM PCRs as for calculating the boot
797  * aggregate digest as stored in the measurement list.
798  */
799 static int ima_calc_boot_aggregate_tfm(char *digest, u16 alg_id,
800                                        struct crypto_shash *tfm)
801 {
802         struct tpm_digest d = { .alg_id = alg_id, .digest = {0} };
803         int rc;
804         u32 i;
805         SHASH_DESC_ON_STACK(shash, tfm);
806
807         shash->tfm = tfm;
808
809         pr_devel("calculating the boot-aggregate based on TPM bank: %04x\n",
810                  d.alg_id);
811
812         rc = crypto_shash_init(shash);
813         if (rc != 0)
814                 return rc;
815
816         /* cumulative digest over TPM registers 0-7 */
817         for (i = TPM_PCR0; i < TPM_PCR8; i++) {
818                 ima_pcrread(i, &d);
819                 /* now accumulate with current aggregate */
820                 rc = crypto_shash_update(shash, d.digest,
821                                          crypto_shash_digestsize(tfm));
822                 if (rc != 0)
823                         return rc;
824         }
825         /*
826          * Extend cumulative digest over TPM registers 8-9, which contain
827          * measurement for the kernel command line (reg. 8) and image (reg. 9)
828          * in a typical PCR allocation. Registers 8-9 are only included in
829          * non-SHA1 boot_aggregate digests to avoid ambiguity.
830          */
831         if (alg_id != TPM_ALG_SHA1) {
832                 for (i = TPM_PCR8; i < TPM_PCR10; i++) {
833                         ima_pcrread(i, &d);
834                         rc = crypto_shash_update(shash, d.digest,
835                                                 crypto_shash_digestsize(tfm));
836                 }
837         }
838         if (!rc)
839                 crypto_shash_final(shash, digest);
840         return rc;
841 }
842
843 int ima_calc_boot_aggregate(struct ima_digest_data *hash)
844 {
845         struct crypto_shash *tfm;
846         u16 crypto_id, alg_id;
847         int rc, i, bank_idx = -1;
848
849         for (i = 0; i < ima_tpm_chip->nr_allocated_banks; i++) {
850                 crypto_id = ima_tpm_chip->allocated_banks[i].crypto_id;
851                 if (crypto_id == hash->algo) {
852                         bank_idx = i;
853                         break;
854                 }
855
856                 if (crypto_id == HASH_ALGO_SHA256)
857                         bank_idx = i;
858
859                 if (bank_idx == -1 && crypto_id == HASH_ALGO_SHA1)
860                         bank_idx = i;
861         }
862
863         if (bank_idx == -1) {
864                 pr_err("No suitable TPM algorithm for boot aggregate\n");
865                 return 0;
866         }
867
868         hash->algo = ima_tpm_chip->allocated_banks[bank_idx].crypto_id;
869
870         tfm = ima_alloc_tfm(hash->algo);
871         if (IS_ERR(tfm))
872                 return PTR_ERR(tfm);
873
874         hash->length = crypto_shash_digestsize(tfm);
875         alg_id = ima_tpm_chip->allocated_banks[bank_idx].alg_id;
876         rc = ima_calc_boot_aggregate_tfm(hash->digest, alg_id, tfm);
877
878         ima_free_tfm(tfm);
879
880         return rc;
881 }