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TOMOYO Linux Cross Reference
Linux/security/integrity/ima/ima_crypto.c

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  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                 if (rc != 0)
833                         return rc;
834         }
835         /*
836          * Extend cumulative digest over TPM registers 8-9, which contain
837          * measurement for the kernel command line (reg. 8) and image (reg. 9)
838          * in a typical PCR allocation. Registers 8-9 are only included in
839          * non-SHA1 boot_aggregate digests to avoid ambiguity.
840          */
841         if (alg_id != TPM_ALG_SHA1) {
842                 for (i = TPM_PCR8; i < TPM_PCR10; i++) {
843                         ima_pcrread(i, &d);
844                         rc = crypto_shash_update(shash, d.digest,
845                                                 crypto_shash_digestsize(tfm));
846                 }
847         }
848         if (!rc)
849                 crypto_shash_final(shash, digest);
850         return rc;
851 }
852 
853 int ima_calc_boot_aggregate(struct ima_digest_data *hash)
854 {
855         struct crypto_shash *tfm;
856         u16 crypto_id, alg_id;
857         int rc, i, bank_idx = -1;
858 
859         for (i = 0; i < ima_tpm_chip->nr_allocated_banks; i++) {
860                 crypto_id = ima_tpm_chip->allocated_banks[i].crypto_id;
861                 if (crypto_id == hash->algo) {
862                         bank_idx = i;
863                         break;
864                 }
865 
866                 if (crypto_id == HASH_ALGO_SHA256)
867                         bank_idx = i;
868 
869                 if (bank_idx == -1 && crypto_id == HASH_ALGO_SHA1)
870                         bank_idx = i;
871         }
872 
873         if (bank_idx == -1) {
874                 pr_err("No suitable TPM algorithm for boot aggregate\n");
875                 return 0;
876         }
877 
878         hash->algo = ima_tpm_chip->allocated_banks[bank_idx].crypto_id;
879 
880         tfm = ima_alloc_tfm(hash->algo);
881         if (IS_ERR(tfm))
882                 return PTR_ERR(tfm);
883 
884         hash->length = crypto_shash_digestsize(tfm);
885         alg_id = ima_tpm_chip->allocated_banks[bank_idx].alg_id;
886         rc = ima_calc_boot_aggregate_tfm(hash->digest, alg_id, tfm);
887 
888         ima_free_tfm(tfm);
889 
890         return rc;
891 }
892 

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