This source file includes following definitions.
- param_set_bufsize
- ima_init_crypto
- ima_alloc_tfm
- ima_free_tfm
- ima_alloc_pages
- ima_free_pages
- ima_alloc_atfm
- ima_free_atfm
- ahash_wait
- ima_calc_file_hash_atfm
- ima_calc_file_ahash
- ima_calc_file_hash_tfm
- ima_calc_file_shash
- ima_calc_file_hash
- ima_calc_field_array_hash_tfm
- ima_calc_field_array_hash
- calc_buffer_ahash_atfm
- calc_buffer_ahash
- calc_buffer_shash_tfm
- calc_buffer_shash
- ima_calc_buffer_hash
- ima_pcrread
- ima_calc_boot_aggregate_tfm
- ima_calc_boot_aggregate
1
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12
13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
14
15 #include <linux/kernel.h>
16 #include <linux/moduleparam.h>
17 #include <linux/ratelimit.h>
18 #include <linux/file.h>
19 #include <linux/crypto.h>
20 #include <linux/scatterlist.h>
21 #include <linux/err.h>
22 #include <linux/slab.h>
23 #include <crypto/hash.h>
24
25 #include "ima.h"
26
27
28 static unsigned long ima_ahash_minsize;
29 module_param_named(ahash_minsize, ima_ahash_minsize, ulong, 0644);
30 MODULE_PARM_DESC(ahash_minsize, "Minimum file size for ahash use");
31
32
33 static int ima_maxorder;
34 static unsigned int ima_bufsize = PAGE_SIZE;
35
36 static int param_set_bufsize(const char *val, const struct kernel_param *kp)
37 {
38 unsigned long long size;
39 int order;
40
41 size = memparse(val, NULL);
42 order = get_order(size);
43 if (order >= MAX_ORDER)
44 return -EINVAL;
45 ima_maxorder = order;
46 ima_bufsize = PAGE_SIZE << order;
47 return 0;
48 }
49
50 static const struct kernel_param_ops param_ops_bufsize = {
51 .set = param_set_bufsize,
52 .get = param_get_uint,
53 };
54 #define param_check_bufsize(name, p) __param_check(name, p, unsigned int)
55
56 module_param_named(ahash_bufsize, ima_bufsize, bufsize, 0644);
57 MODULE_PARM_DESC(ahash_bufsize, "Maximum ahash buffer size");
58
59 static struct crypto_shash *ima_shash_tfm;
60 static struct crypto_ahash *ima_ahash_tfm;
61
62 int __init ima_init_crypto(void)
63 {
64 long rc;
65
66 ima_shash_tfm = crypto_alloc_shash(hash_algo_name[ima_hash_algo], 0, 0);
67 if (IS_ERR(ima_shash_tfm)) {
68 rc = PTR_ERR(ima_shash_tfm);
69 pr_err("Can not allocate %s (reason: %ld)\n",
70 hash_algo_name[ima_hash_algo], rc);
71 return rc;
72 }
73 pr_info("Allocated hash algorithm: %s\n",
74 hash_algo_name[ima_hash_algo]);
75 return 0;
76 }
77
78 static struct crypto_shash *ima_alloc_tfm(enum hash_algo algo)
79 {
80 struct crypto_shash *tfm = ima_shash_tfm;
81 int rc;
82
83 if (algo < 0 || algo >= HASH_ALGO__LAST)
84 algo = ima_hash_algo;
85
86 if (algo != ima_hash_algo) {
87 tfm = crypto_alloc_shash(hash_algo_name[algo], 0, 0);
88 if (IS_ERR(tfm)) {
89 rc = PTR_ERR(tfm);
90 pr_err("Can not allocate %s (reason: %d)\n",
91 hash_algo_name[algo], rc);
92 }
93 }
94 return tfm;
95 }
96
97 static void ima_free_tfm(struct crypto_shash *tfm)
98 {
99 if (tfm != ima_shash_tfm)
100 crypto_free_shash(tfm);
101 }
102
103
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115
116
117
118 static void *ima_alloc_pages(loff_t max_size, size_t *allocated_size,
119 int last_warn)
120 {
121 void *ptr;
122 int order = ima_maxorder;
123 gfp_t gfp_mask = __GFP_RECLAIM | __GFP_NOWARN | __GFP_NORETRY;
124
125 if (order)
126 order = min(get_order(max_size), order);
127
128 for (; order; order--) {
129 ptr = (void *)__get_free_pages(gfp_mask, order);
130 if (ptr) {
131 *allocated_size = PAGE_SIZE << order;
132 return ptr;
133 }
134 }
135
136
137
138 gfp_mask = GFP_KERNEL;
139
140 if (!last_warn)
141 gfp_mask |= __GFP_NOWARN;
142
143 ptr = (void *)__get_free_pages(gfp_mask, 0);
144 if (ptr) {
145 *allocated_size = PAGE_SIZE;
146 return ptr;
147 }
148
149 *allocated_size = 0;
150 return NULL;
151 }
152
153
154
155
156
157
158 static void ima_free_pages(void *ptr, size_t size)
159 {
160 if (!ptr)
161 return;
162 free_pages((unsigned long)ptr, get_order(size));
163 }
164
165 static struct crypto_ahash *ima_alloc_atfm(enum hash_algo algo)
166 {
167 struct crypto_ahash *tfm = ima_ahash_tfm;
168 int rc;
169
170 if (algo < 0 || algo >= HASH_ALGO__LAST)
171 algo = ima_hash_algo;
172
173 if (algo != ima_hash_algo || !tfm) {
174 tfm = crypto_alloc_ahash(hash_algo_name[algo], 0, 0);
175 if (!IS_ERR(tfm)) {
176 if (algo == ima_hash_algo)
177 ima_ahash_tfm = tfm;
178 } else {
179 rc = PTR_ERR(tfm);
180 pr_err("Can not allocate %s (reason: %d)\n",
181 hash_algo_name[algo], rc);
182 }
183 }
184 return tfm;
185 }
186
187 static void ima_free_atfm(struct crypto_ahash *tfm)
188 {
189 if (tfm != ima_ahash_tfm)
190 crypto_free_ahash(tfm);
191 }
192
193 static inline int ahash_wait(int err, struct crypto_wait *wait)
194 {
195
196 err = crypto_wait_req(err, wait);
197
198 if (err)
199 pr_crit_ratelimited("ahash calculation failed: err: %d\n", err);
200
201 return err;
202 }
203
204 static int ima_calc_file_hash_atfm(struct file *file,
205 struct ima_digest_data *hash,
206 struct crypto_ahash *tfm)
207 {
208 loff_t i_size, offset;
209 char *rbuf[2] = { NULL, };
210 int rc, rbuf_len, active = 0, ahash_rc = 0;
211 struct ahash_request *req;
212 struct scatterlist sg[1];
213 struct crypto_wait wait;
214 size_t rbuf_size[2];
215
216 hash->length = crypto_ahash_digestsize(tfm);
217
218 req = ahash_request_alloc(tfm, GFP_KERNEL);
219 if (!req)
220 return -ENOMEM;
221
222 crypto_init_wait(&wait);
223 ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
224 CRYPTO_TFM_REQ_MAY_SLEEP,
225 crypto_req_done, &wait);
226
227 rc = ahash_wait(crypto_ahash_init(req), &wait);
228 if (rc)
229 goto out1;
230
231 i_size = i_size_read(file_inode(file));
232
233 if (i_size == 0)
234 goto out2;
235
236
237
238
239
240 rbuf[0] = ima_alloc_pages(i_size, &rbuf_size[0], 1);
241 if (!rbuf[0]) {
242 rc = -ENOMEM;
243 goto out1;
244 }
245
246
247 if (i_size > rbuf_size[0]) {
248
249
250
251
252
253 rbuf[1] = ima_alloc_pages(i_size - rbuf_size[0],
254 &rbuf_size[1], 0);
255 }
256
257 for (offset = 0; offset < i_size; offset += rbuf_len) {
258 if (!rbuf[1] && offset) {
259
260
261
262
263 rc = ahash_wait(ahash_rc, &wait);
264 if (rc)
265 goto out3;
266 }
267
268 rbuf_len = min_t(loff_t, i_size - offset, rbuf_size[active]);
269 rc = integrity_kernel_read(file, offset, rbuf[active],
270 rbuf_len);
271 if (rc != rbuf_len) {
272 if (rc >= 0)
273 rc = -EINVAL;
274
275
276
277
278 ahash_wait(ahash_rc, &wait);
279 goto out3;
280 }
281
282 if (rbuf[1] && offset) {
283
284
285
286
287 rc = ahash_wait(ahash_rc, &wait);
288 if (rc)
289 goto out3;
290 }
291
292 sg_init_one(&sg[0], rbuf[active], rbuf_len);
293 ahash_request_set_crypt(req, sg, NULL, rbuf_len);
294
295 ahash_rc = crypto_ahash_update(req);
296
297 if (rbuf[1])
298 active = !active;
299 }
300
301 rc = ahash_wait(ahash_rc, &wait);
302 out3:
303 ima_free_pages(rbuf[0], rbuf_size[0]);
304 ima_free_pages(rbuf[1], rbuf_size[1]);
305 out2:
306 if (!rc) {
307 ahash_request_set_crypt(req, NULL, hash->digest, 0);
308 rc = ahash_wait(crypto_ahash_final(req), &wait);
309 }
310 out1:
311 ahash_request_free(req);
312 return rc;
313 }
314
315 static int ima_calc_file_ahash(struct file *file, struct ima_digest_data *hash)
316 {
317 struct crypto_ahash *tfm;
318 int rc;
319
320 tfm = ima_alloc_atfm(hash->algo);
321 if (IS_ERR(tfm))
322 return PTR_ERR(tfm);
323
324 rc = ima_calc_file_hash_atfm(file, hash, tfm);
325
326 ima_free_atfm(tfm);
327
328 return rc;
329 }
330
331 static int ima_calc_file_hash_tfm(struct file *file,
332 struct ima_digest_data *hash,
333 struct crypto_shash *tfm)
334 {
335 loff_t i_size, offset = 0;
336 char *rbuf;
337 int rc;
338 SHASH_DESC_ON_STACK(shash, tfm);
339
340 shash->tfm = tfm;
341
342 hash->length = crypto_shash_digestsize(tfm);
343
344 rc = crypto_shash_init(shash);
345 if (rc != 0)
346 return rc;
347
348 i_size = i_size_read(file_inode(file));
349
350 if (i_size == 0)
351 goto out;
352
353 rbuf = kzalloc(PAGE_SIZE, GFP_KERNEL);
354 if (!rbuf)
355 return -ENOMEM;
356
357 while (offset < i_size) {
358 int rbuf_len;
359
360 rbuf_len = integrity_kernel_read(file, offset, rbuf, PAGE_SIZE);
361 if (rbuf_len < 0) {
362 rc = rbuf_len;
363 break;
364 }
365 if (rbuf_len == 0)
366 break;
367 offset += rbuf_len;
368
369 rc = crypto_shash_update(shash, rbuf, rbuf_len);
370 if (rc)
371 break;
372 }
373 kfree(rbuf);
374 out:
375 if (!rc)
376 rc = crypto_shash_final(shash, hash->digest);
377 return rc;
378 }
379
380 static int ima_calc_file_shash(struct file *file, struct ima_digest_data *hash)
381 {
382 struct crypto_shash *tfm;
383 int rc;
384
385 tfm = ima_alloc_tfm(hash->algo);
386 if (IS_ERR(tfm))
387 return PTR_ERR(tfm);
388
389 rc = ima_calc_file_hash_tfm(file, hash, tfm);
390
391 ima_free_tfm(tfm);
392
393 return rc;
394 }
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407
408
409 int ima_calc_file_hash(struct file *file, struct ima_digest_data *hash)
410 {
411 loff_t i_size;
412 int rc;
413 struct file *f = file;
414 bool new_file_instance = false, modified_mode = false;
415
416
417
418
419
420 if (file->f_flags & O_DIRECT) {
421 hash->length = hash_digest_size[ima_hash_algo];
422 hash->algo = ima_hash_algo;
423 return -EINVAL;
424 }
425
426
427 if (!(file->f_mode & FMODE_READ)) {
428 int flags = file->f_flags & ~(O_WRONLY | O_APPEND |
429 O_TRUNC | O_CREAT | O_NOCTTY | O_EXCL);
430 flags |= O_RDONLY;
431 f = dentry_open(&file->f_path, flags, file->f_cred);
432 if (IS_ERR(f)) {
433
434
435
436
437 pr_info_ratelimited("Unable to reopen file for reading.\n");
438 f = file;
439 f->f_mode |= FMODE_READ;
440 modified_mode = true;
441 } else {
442 new_file_instance = true;
443 }
444 }
445
446 i_size = i_size_read(file_inode(f));
447
448 if (ima_ahash_minsize && i_size >= ima_ahash_minsize) {
449 rc = ima_calc_file_ahash(f, hash);
450 if (!rc)
451 goto out;
452 }
453
454 rc = ima_calc_file_shash(f, hash);
455 out:
456 if (new_file_instance)
457 fput(f);
458 else if (modified_mode)
459 f->f_mode &= ~FMODE_READ;
460 return rc;
461 }
462
463
464
465
466 static int ima_calc_field_array_hash_tfm(struct ima_field_data *field_data,
467 struct ima_template_desc *td,
468 int num_fields,
469 struct ima_digest_data *hash,
470 struct crypto_shash *tfm)
471 {
472 SHASH_DESC_ON_STACK(shash, tfm);
473 int rc, i;
474
475 shash->tfm = tfm;
476
477 hash->length = crypto_shash_digestsize(tfm);
478
479 rc = crypto_shash_init(shash);
480 if (rc != 0)
481 return rc;
482
483 for (i = 0; i < num_fields; i++) {
484 u8 buffer[IMA_EVENT_NAME_LEN_MAX + 1] = { 0 };
485 u8 *data_to_hash = field_data[i].data;
486 u32 datalen = field_data[i].len;
487 u32 datalen_to_hash =
488 !ima_canonical_fmt ? datalen : cpu_to_le32(datalen);
489
490 if (strcmp(td->name, IMA_TEMPLATE_IMA_NAME) != 0) {
491 rc = crypto_shash_update(shash,
492 (const u8 *) &datalen_to_hash,
493 sizeof(datalen_to_hash));
494 if (rc)
495 break;
496 } else if (strcmp(td->fields[i]->field_id, "n") == 0) {
497 memcpy(buffer, data_to_hash, datalen);
498 data_to_hash = buffer;
499 datalen = IMA_EVENT_NAME_LEN_MAX + 1;
500 }
501 rc = crypto_shash_update(shash, data_to_hash, datalen);
502 if (rc)
503 break;
504 }
505
506 if (!rc)
507 rc = crypto_shash_final(shash, hash->digest);
508
509 return rc;
510 }
511
512 int ima_calc_field_array_hash(struct ima_field_data *field_data,
513 struct ima_template_desc *desc, int num_fields,
514 struct ima_digest_data *hash)
515 {
516 struct crypto_shash *tfm;
517 int rc;
518
519 tfm = ima_alloc_tfm(hash->algo);
520 if (IS_ERR(tfm))
521 return PTR_ERR(tfm);
522
523 rc = ima_calc_field_array_hash_tfm(field_data, desc, num_fields,
524 hash, tfm);
525
526 ima_free_tfm(tfm);
527
528 return rc;
529 }
530
531 static int calc_buffer_ahash_atfm(const void *buf, loff_t len,
532 struct ima_digest_data *hash,
533 struct crypto_ahash *tfm)
534 {
535 struct ahash_request *req;
536 struct scatterlist sg;
537 struct crypto_wait wait;
538 int rc, ahash_rc = 0;
539
540 hash->length = crypto_ahash_digestsize(tfm);
541
542 req = ahash_request_alloc(tfm, GFP_KERNEL);
543 if (!req)
544 return -ENOMEM;
545
546 crypto_init_wait(&wait);
547 ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
548 CRYPTO_TFM_REQ_MAY_SLEEP,
549 crypto_req_done, &wait);
550
551 rc = ahash_wait(crypto_ahash_init(req), &wait);
552 if (rc)
553 goto out;
554
555 sg_init_one(&sg, buf, len);
556 ahash_request_set_crypt(req, &sg, NULL, len);
557
558 ahash_rc = crypto_ahash_update(req);
559
560
561 rc = ahash_wait(ahash_rc, &wait);
562 if (!rc) {
563 ahash_request_set_crypt(req, NULL, hash->digest, 0);
564 rc = ahash_wait(crypto_ahash_final(req), &wait);
565 }
566 out:
567 ahash_request_free(req);
568 return rc;
569 }
570
571 static int calc_buffer_ahash(const void *buf, loff_t len,
572 struct ima_digest_data *hash)
573 {
574 struct crypto_ahash *tfm;
575 int rc;
576
577 tfm = ima_alloc_atfm(hash->algo);
578 if (IS_ERR(tfm))
579 return PTR_ERR(tfm);
580
581 rc = calc_buffer_ahash_atfm(buf, len, hash, tfm);
582
583 ima_free_atfm(tfm);
584
585 return rc;
586 }
587
588 static int calc_buffer_shash_tfm(const void *buf, loff_t size,
589 struct ima_digest_data *hash,
590 struct crypto_shash *tfm)
591 {
592 SHASH_DESC_ON_STACK(shash, tfm);
593 unsigned int len;
594 int rc;
595
596 shash->tfm = tfm;
597
598 hash->length = crypto_shash_digestsize(tfm);
599
600 rc = crypto_shash_init(shash);
601 if (rc != 0)
602 return rc;
603
604 while (size) {
605 len = size < PAGE_SIZE ? size : PAGE_SIZE;
606 rc = crypto_shash_update(shash, buf, len);
607 if (rc)
608 break;
609 buf += len;
610 size -= len;
611 }
612
613 if (!rc)
614 rc = crypto_shash_final(shash, hash->digest);
615 return rc;
616 }
617
618 static int calc_buffer_shash(const void *buf, loff_t len,
619 struct ima_digest_data *hash)
620 {
621 struct crypto_shash *tfm;
622 int rc;
623
624 tfm = ima_alloc_tfm(hash->algo);
625 if (IS_ERR(tfm))
626 return PTR_ERR(tfm);
627
628 rc = calc_buffer_shash_tfm(buf, len, hash, tfm);
629
630 ima_free_tfm(tfm);
631 return rc;
632 }
633
634 int ima_calc_buffer_hash(const void *buf, loff_t len,
635 struct ima_digest_data *hash)
636 {
637 int rc;
638
639 if (ima_ahash_minsize && len >= ima_ahash_minsize) {
640 rc = calc_buffer_ahash(buf, len, hash);
641 if (!rc)
642 return 0;
643 }
644
645 return calc_buffer_shash(buf, len, hash);
646 }
647
648 static void __init ima_pcrread(u32 idx, struct tpm_digest *d)
649 {
650 if (!ima_tpm_chip)
651 return;
652
653 if (tpm_pcr_read(ima_tpm_chip, idx, d) != 0)
654 pr_err("Error Communicating to TPM chip\n");
655 }
656
657
658
659
660 static int __init ima_calc_boot_aggregate_tfm(char *digest,
661 struct crypto_shash *tfm)
662 {
663 struct tpm_digest d = { .alg_id = TPM_ALG_SHA1, .digest = {0} };
664 int rc;
665 u32 i;
666 SHASH_DESC_ON_STACK(shash, tfm);
667
668 shash->tfm = tfm;
669
670 rc = crypto_shash_init(shash);
671 if (rc != 0)
672 return rc;
673
674
675 for (i = TPM_PCR0; i < TPM_PCR8; i++) {
676 ima_pcrread(i, &d);
677
678 rc = crypto_shash_update(shash, d.digest, TPM_DIGEST_SIZE);
679 }
680 if (!rc)
681 crypto_shash_final(shash, digest);
682 return rc;
683 }
684
685 int __init ima_calc_boot_aggregate(struct ima_digest_data *hash)
686 {
687 struct crypto_shash *tfm;
688 int rc;
689
690 tfm = ima_alloc_tfm(hash->algo);
691 if (IS_ERR(tfm))
692 return PTR_ERR(tfm);
693
694 hash->length = crypto_shash_digestsize(tfm);
695 rc = ima_calc_boot_aggregate_tfm(hash->digest, tfm);
696
697 ima_free_tfm(tfm);
698
699 return rc;
700 }