This source file includes following definitions.
- aes_get_sizes
- valid_ecryptfs_desc
- valid_master_desc
- datablob_parse
- datablob_format
- request_user_key
- calc_hash
- calc_hmac
- get_derived_key
- init_skcipher_req
- request_master_key
- derived_key_encrypt
- datablob_hmac_append
- datablob_hmac_verify
- derived_key_decrypt
- encrypted_key_alloc
- encrypted_key_decrypt
- __ekey_init
- encrypted_init
- encrypted_instantiate
- encrypted_rcu_free
- encrypted_update
- encrypted_read
- encrypted_destroy
- init_encrypted
- cleanup_encrypted
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14 #include <linux/uaccess.h>
15 #include <linux/module.h>
16 #include <linux/init.h>
17 #include <linux/slab.h>
18 #include <linux/parser.h>
19 #include <linux/string.h>
20 #include <linux/err.h>
21 #include <keys/user-type.h>
22 #include <keys/trusted-type.h>
23 #include <keys/encrypted-type.h>
24 #include <linux/key-type.h>
25 #include <linux/random.h>
26 #include <linux/rcupdate.h>
27 #include <linux/scatterlist.h>
28 #include <linux/ctype.h>
29 #include <crypto/aes.h>
30 #include <crypto/algapi.h>
31 #include <crypto/hash.h>
32 #include <crypto/sha.h>
33 #include <crypto/skcipher.h>
34
35 #include "encrypted.h"
36 #include "ecryptfs_format.h"
37
38 static const char KEY_TRUSTED_PREFIX[] = "trusted:";
39 static const char KEY_USER_PREFIX[] = "user:";
40 static const char hash_alg[] = "sha256";
41 static const char hmac_alg[] = "hmac(sha256)";
42 static const char blkcipher_alg[] = "cbc(aes)";
43 static const char key_format_default[] = "default";
44 static const char key_format_ecryptfs[] = "ecryptfs";
45 static const char key_format_enc32[] = "enc32";
46 static unsigned int ivsize;
47 static int blksize;
48
49 #define KEY_TRUSTED_PREFIX_LEN (sizeof (KEY_TRUSTED_PREFIX) - 1)
50 #define KEY_USER_PREFIX_LEN (sizeof (KEY_USER_PREFIX) - 1)
51 #define KEY_ECRYPTFS_DESC_LEN 16
52 #define HASH_SIZE SHA256_DIGEST_SIZE
53 #define MAX_DATA_SIZE 4096
54 #define MIN_DATA_SIZE 20
55 #define KEY_ENC32_PAYLOAD_LEN 32
56
57 static struct crypto_shash *hash_tfm;
58
59 enum {
60 Opt_new, Opt_load, Opt_update, Opt_err
61 };
62
63 enum {
64 Opt_default, Opt_ecryptfs, Opt_enc32, Opt_error
65 };
66
67 static const match_table_t key_format_tokens = {
68 {Opt_default, "default"},
69 {Opt_ecryptfs, "ecryptfs"},
70 {Opt_enc32, "enc32"},
71 {Opt_error, NULL}
72 };
73
74 static const match_table_t key_tokens = {
75 {Opt_new, "new"},
76 {Opt_load, "load"},
77 {Opt_update, "update"},
78 {Opt_err, NULL}
79 };
80
81 static int aes_get_sizes(void)
82 {
83 struct crypto_skcipher *tfm;
84
85 tfm = crypto_alloc_skcipher(blkcipher_alg, 0, CRYPTO_ALG_ASYNC);
86 if (IS_ERR(tfm)) {
87 pr_err("encrypted_key: failed to alloc_cipher (%ld)\n",
88 PTR_ERR(tfm));
89 return PTR_ERR(tfm);
90 }
91 ivsize = crypto_skcipher_ivsize(tfm);
92 blksize = crypto_skcipher_blocksize(tfm);
93 crypto_free_skcipher(tfm);
94 return 0;
95 }
96
97
98
99
100
101
102
103
104 static int valid_ecryptfs_desc(const char *ecryptfs_desc)
105 {
106 int i;
107
108 if (strlen(ecryptfs_desc) != KEY_ECRYPTFS_DESC_LEN) {
109 pr_err("encrypted_key: key description must be %d hexadecimal "
110 "characters long\n", KEY_ECRYPTFS_DESC_LEN);
111 return -EINVAL;
112 }
113
114 for (i = 0; i < KEY_ECRYPTFS_DESC_LEN; i++) {
115 if (!isxdigit(ecryptfs_desc[i])) {
116 pr_err("encrypted_key: key description must contain "
117 "only hexadecimal characters\n");
118 return -EINVAL;
119 }
120 }
121
122 return 0;
123 }
124
125
126
127
128
129
130
131
132
133
134
135
136
137 static int valid_master_desc(const char *new_desc, const char *orig_desc)
138 {
139 int prefix_len;
140
141 if (!strncmp(new_desc, KEY_TRUSTED_PREFIX, KEY_TRUSTED_PREFIX_LEN))
142 prefix_len = KEY_TRUSTED_PREFIX_LEN;
143 else if (!strncmp(new_desc, KEY_USER_PREFIX, KEY_USER_PREFIX_LEN))
144 prefix_len = KEY_USER_PREFIX_LEN;
145 else
146 return -EINVAL;
147
148 if (!new_desc[prefix_len])
149 return -EINVAL;
150
151 if (orig_desc && strncmp(new_desc, orig_desc, prefix_len))
152 return -EINVAL;
153
154 return 0;
155 }
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171 static int datablob_parse(char *datablob, const char **format,
172 char **master_desc, char **decrypted_datalen,
173 char **hex_encoded_iv)
174 {
175 substring_t args[MAX_OPT_ARGS];
176 int ret = -EINVAL;
177 int key_cmd;
178 int key_format;
179 char *p, *keyword;
180
181 keyword = strsep(&datablob, " \t");
182 if (!keyword) {
183 pr_info("encrypted_key: insufficient parameters specified\n");
184 return ret;
185 }
186 key_cmd = match_token(keyword, key_tokens, args);
187
188
189 p = strsep(&datablob, " \t");
190 if (!p) {
191 pr_err("encrypted_key: insufficient parameters specified\n");
192 return ret;
193 }
194
195 key_format = match_token(p, key_format_tokens, args);
196 switch (key_format) {
197 case Opt_ecryptfs:
198 case Opt_enc32:
199 case Opt_default:
200 *format = p;
201 *master_desc = strsep(&datablob, " \t");
202 break;
203 case Opt_error:
204 *master_desc = p;
205 break;
206 }
207
208 if (!*master_desc) {
209 pr_info("encrypted_key: master key parameter is missing\n");
210 goto out;
211 }
212
213 if (valid_master_desc(*master_desc, NULL) < 0) {
214 pr_info("encrypted_key: master key parameter \'%s\' "
215 "is invalid\n", *master_desc);
216 goto out;
217 }
218
219 if (decrypted_datalen) {
220 *decrypted_datalen = strsep(&datablob, " \t");
221 if (!*decrypted_datalen) {
222 pr_info("encrypted_key: keylen parameter is missing\n");
223 goto out;
224 }
225 }
226
227 switch (key_cmd) {
228 case Opt_new:
229 if (!decrypted_datalen) {
230 pr_info("encrypted_key: keyword \'%s\' not allowed "
231 "when called from .update method\n", keyword);
232 break;
233 }
234 ret = 0;
235 break;
236 case Opt_load:
237 if (!decrypted_datalen) {
238 pr_info("encrypted_key: keyword \'%s\' not allowed "
239 "when called from .update method\n", keyword);
240 break;
241 }
242 *hex_encoded_iv = strsep(&datablob, " \t");
243 if (!*hex_encoded_iv) {
244 pr_info("encrypted_key: hex blob is missing\n");
245 break;
246 }
247 ret = 0;
248 break;
249 case Opt_update:
250 if (decrypted_datalen) {
251 pr_info("encrypted_key: keyword \'%s\' not allowed "
252 "when called from .instantiate method\n",
253 keyword);
254 break;
255 }
256 ret = 0;
257 break;
258 case Opt_err:
259 pr_info("encrypted_key: keyword \'%s\' not recognized\n",
260 keyword);
261 break;
262 }
263 out:
264 return ret;
265 }
266
267
268
269
270 static char *datablob_format(struct encrypted_key_payload *epayload,
271 size_t asciiblob_len)
272 {
273 char *ascii_buf, *bufp;
274 u8 *iv = epayload->iv;
275 int len;
276 int i;
277
278 ascii_buf = kmalloc(asciiblob_len + 1, GFP_KERNEL);
279 if (!ascii_buf)
280 goto out;
281
282 ascii_buf[asciiblob_len] = '\0';
283
284
285 len = sprintf(ascii_buf, "%s %s %s ", epayload->format,
286 epayload->master_desc, epayload->datalen);
287
288
289 bufp = &ascii_buf[len];
290 for (i = 0; i < (asciiblob_len - len) / 2; i++)
291 bufp = hex_byte_pack(bufp, iv[i]);
292 out:
293 return ascii_buf;
294 }
295
296
297
298
299
300
301 static struct key *request_user_key(const char *master_desc, const u8 **master_key,
302 size_t *master_keylen)
303 {
304 const struct user_key_payload *upayload;
305 struct key *ukey;
306
307 ukey = request_key(&key_type_user, master_desc, NULL);
308 if (IS_ERR(ukey))
309 goto error;
310
311 down_read(&ukey->sem);
312 upayload = user_key_payload_locked(ukey);
313 if (!upayload) {
314
315 up_read(&ukey->sem);
316 key_put(ukey);
317 ukey = ERR_PTR(-EKEYREVOKED);
318 goto error;
319 }
320 *master_key = upayload->data;
321 *master_keylen = upayload->datalen;
322 error:
323 return ukey;
324 }
325
326 static int calc_hash(struct crypto_shash *tfm, u8 *digest,
327 const u8 *buf, unsigned int buflen)
328 {
329 SHASH_DESC_ON_STACK(desc, tfm);
330 int err;
331
332 desc->tfm = tfm;
333
334 err = crypto_shash_digest(desc, buf, buflen, digest);
335 shash_desc_zero(desc);
336 return err;
337 }
338
339 static int calc_hmac(u8 *digest, const u8 *key, unsigned int keylen,
340 const u8 *buf, unsigned int buflen)
341 {
342 struct crypto_shash *tfm;
343 int err;
344
345 tfm = crypto_alloc_shash(hmac_alg, 0, 0);
346 if (IS_ERR(tfm)) {
347 pr_err("encrypted_key: can't alloc %s transform: %ld\n",
348 hmac_alg, PTR_ERR(tfm));
349 return PTR_ERR(tfm);
350 }
351
352 err = crypto_shash_setkey(tfm, key, keylen);
353 if (!err)
354 err = calc_hash(tfm, digest, buf, buflen);
355 crypto_free_shash(tfm);
356 return err;
357 }
358
359 enum derived_key_type { ENC_KEY, AUTH_KEY };
360
361
362 static int get_derived_key(u8 *derived_key, enum derived_key_type key_type,
363 const u8 *master_key, size_t master_keylen)
364 {
365 u8 *derived_buf;
366 unsigned int derived_buf_len;
367 int ret;
368
369 derived_buf_len = strlen("AUTH_KEY") + 1 + master_keylen;
370 if (derived_buf_len < HASH_SIZE)
371 derived_buf_len = HASH_SIZE;
372
373 derived_buf = kzalloc(derived_buf_len, GFP_KERNEL);
374 if (!derived_buf)
375 return -ENOMEM;
376
377 if (key_type)
378 strcpy(derived_buf, "AUTH_KEY");
379 else
380 strcpy(derived_buf, "ENC_KEY");
381
382 memcpy(derived_buf + strlen(derived_buf) + 1, master_key,
383 master_keylen);
384 ret = calc_hash(hash_tfm, derived_key, derived_buf, derived_buf_len);
385 kzfree(derived_buf);
386 return ret;
387 }
388
389 static struct skcipher_request *init_skcipher_req(const u8 *key,
390 unsigned int key_len)
391 {
392 struct skcipher_request *req;
393 struct crypto_skcipher *tfm;
394 int ret;
395
396 tfm = crypto_alloc_skcipher(blkcipher_alg, 0, CRYPTO_ALG_ASYNC);
397 if (IS_ERR(tfm)) {
398 pr_err("encrypted_key: failed to load %s transform (%ld)\n",
399 blkcipher_alg, PTR_ERR(tfm));
400 return ERR_CAST(tfm);
401 }
402
403 ret = crypto_skcipher_setkey(tfm, key, key_len);
404 if (ret < 0) {
405 pr_err("encrypted_key: failed to setkey (%d)\n", ret);
406 crypto_free_skcipher(tfm);
407 return ERR_PTR(ret);
408 }
409
410 req = skcipher_request_alloc(tfm, GFP_KERNEL);
411 if (!req) {
412 pr_err("encrypted_key: failed to allocate request for %s\n",
413 blkcipher_alg);
414 crypto_free_skcipher(tfm);
415 return ERR_PTR(-ENOMEM);
416 }
417
418 skcipher_request_set_callback(req, 0, NULL, NULL);
419 return req;
420 }
421
422 static struct key *request_master_key(struct encrypted_key_payload *epayload,
423 const u8 **master_key, size_t *master_keylen)
424 {
425 struct key *mkey = ERR_PTR(-EINVAL);
426
427 if (!strncmp(epayload->master_desc, KEY_TRUSTED_PREFIX,
428 KEY_TRUSTED_PREFIX_LEN)) {
429 mkey = request_trusted_key(epayload->master_desc +
430 KEY_TRUSTED_PREFIX_LEN,
431 master_key, master_keylen);
432 } else if (!strncmp(epayload->master_desc, KEY_USER_PREFIX,
433 KEY_USER_PREFIX_LEN)) {
434 mkey = request_user_key(epayload->master_desc +
435 KEY_USER_PREFIX_LEN,
436 master_key, master_keylen);
437 } else
438 goto out;
439
440 if (IS_ERR(mkey)) {
441 int ret = PTR_ERR(mkey);
442
443 if (ret == -ENOTSUPP)
444 pr_info("encrypted_key: key %s not supported",
445 epayload->master_desc);
446 else
447 pr_info("encrypted_key: key %s not found",
448 epayload->master_desc);
449 goto out;
450 }
451
452 dump_master_key(*master_key, *master_keylen);
453 out:
454 return mkey;
455 }
456
457
458 static int derived_key_encrypt(struct encrypted_key_payload *epayload,
459 const u8 *derived_key,
460 unsigned int derived_keylen)
461 {
462 struct scatterlist sg_in[2];
463 struct scatterlist sg_out[1];
464 struct crypto_skcipher *tfm;
465 struct skcipher_request *req;
466 unsigned int encrypted_datalen;
467 u8 iv[AES_BLOCK_SIZE];
468 int ret;
469
470 encrypted_datalen = roundup(epayload->decrypted_datalen, blksize);
471
472 req = init_skcipher_req(derived_key, derived_keylen);
473 ret = PTR_ERR(req);
474 if (IS_ERR(req))
475 goto out;
476 dump_decrypted_data(epayload);
477
478 sg_init_table(sg_in, 2);
479 sg_set_buf(&sg_in[0], epayload->decrypted_data,
480 epayload->decrypted_datalen);
481 sg_set_page(&sg_in[1], ZERO_PAGE(0), AES_BLOCK_SIZE, 0);
482
483 sg_init_table(sg_out, 1);
484 sg_set_buf(sg_out, epayload->encrypted_data, encrypted_datalen);
485
486 memcpy(iv, epayload->iv, sizeof(iv));
487 skcipher_request_set_crypt(req, sg_in, sg_out, encrypted_datalen, iv);
488 ret = crypto_skcipher_encrypt(req);
489 tfm = crypto_skcipher_reqtfm(req);
490 skcipher_request_free(req);
491 crypto_free_skcipher(tfm);
492 if (ret < 0)
493 pr_err("encrypted_key: failed to encrypt (%d)\n", ret);
494 else
495 dump_encrypted_data(epayload, encrypted_datalen);
496 out:
497 return ret;
498 }
499
500 static int datablob_hmac_append(struct encrypted_key_payload *epayload,
501 const u8 *master_key, size_t master_keylen)
502 {
503 u8 derived_key[HASH_SIZE];
504 u8 *digest;
505 int ret;
506
507 ret = get_derived_key(derived_key, AUTH_KEY, master_key, master_keylen);
508 if (ret < 0)
509 goto out;
510
511 digest = epayload->format + epayload->datablob_len;
512 ret = calc_hmac(digest, derived_key, sizeof derived_key,
513 epayload->format, epayload->datablob_len);
514 if (!ret)
515 dump_hmac(NULL, digest, HASH_SIZE);
516 out:
517 memzero_explicit(derived_key, sizeof(derived_key));
518 return ret;
519 }
520
521
522 static int datablob_hmac_verify(struct encrypted_key_payload *epayload,
523 const u8 *format, const u8 *master_key,
524 size_t master_keylen)
525 {
526 u8 derived_key[HASH_SIZE];
527 u8 digest[HASH_SIZE];
528 int ret;
529 char *p;
530 unsigned short len;
531
532 ret = get_derived_key(derived_key, AUTH_KEY, master_key, master_keylen);
533 if (ret < 0)
534 goto out;
535
536 len = epayload->datablob_len;
537 if (!format) {
538 p = epayload->master_desc;
539 len -= strlen(epayload->format) + 1;
540 } else
541 p = epayload->format;
542
543 ret = calc_hmac(digest, derived_key, sizeof derived_key, p, len);
544 if (ret < 0)
545 goto out;
546 ret = crypto_memneq(digest, epayload->format + epayload->datablob_len,
547 sizeof(digest));
548 if (ret) {
549 ret = -EINVAL;
550 dump_hmac("datablob",
551 epayload->format + epayload->datablob_len,
552 HASH_SIZE);
553 dump_hmac("calc", digest, HASH_SIZE);
554 }
555 out:
556 memzero_explicit(derived_key, sizeof(derived_key));
557 return ret;
558 }
559
560 static int derived_key_decrypt(struct encrypted_key_payload *epayload,
561 const u8 *derived_key,
562 unsigned int derived_keylen)
563 {
564 struct scatterlist sg_in[1];
565 struct scatterlist sg_out[2];
566 struct crypto_skcipher *tfm;
567 struct skcipher_request *req;
568 unsigned int encrypted_datalen;
569 u8 iv[AES_BLOCK_SIZE];
570 u8 *pad;
571 int ret;
572
573
574 pad = kmalloc(AES_BLOCK_SIZE, GFP_KERNEL);
575 if (!pad)
576 return -ENOMEM;
577
578 encrypted_datalen = roundup(epayload->decrypted_datalen, blksize);
579 req = init_skcipher_req(derived_key, derived_keylen);
580 ret = PTR_ERR(req);
581 if (IS_ERR(req))
582 goto out;
583 dump_encrypted_data(epayload, encrypted_datalen);
584
585 sg_init_table(sg_in, 1);
586 sg_init_table(sg_out, 2);
587 sg_set_buf(sg_in, epayload->encrypted_data, encrypted_datalen);
588 sg_set_buf(&sg_out[0], epayload->decrypted_data,
589 epayload->decrypted_datalen);
590 sg_set_buf(&sg_out[1], pad, AES_BLOCK_SIZE);
591
592 memcpy(iv, epayload->iv, sizeof(iv));
593 skcipher_request_set_crypt(req, sg_in, sg_out, encrypted_datalen, iv);
594 ret = crypto_skcipher_decrypt(req);
595 tfm = crypto_skcipher_reqtfm(req);
596 skcipher_request_free(req);
597 crypto_free_skcipher(tfm);
598 if (ret < 0)
599 goto out;
600 dump_decrypted_data(epayload);
601 out:
602 kfree(pad);
603 return ret;
604 }
605
606
607 static struct encrypted_key_payload *encrypted_key_alloc(struct key *key,
608 const char *format,
609 const char *master_desc,
610 const char *datalen)
611 {
612 struct encrypted_key_payload *epayload = NULL;
613 unsigned short datablob_len;
614 unsigned short decrypted_datalen;
615 unsigned short payload_datalen;
616 unsigned int encrypted_datalen;
617 unsigned int format_len;
618 long dlen;
619 int ret;
620
621 ret = kstrtol(datalen, 10, &dlen);
622 if (ret < 0 || dlen < MIN_DATA_SIZE || dlen > MAX_DATA_SIZE)
623 return ERR_PTR(-EINVAL);
624
625 format_len = (!format) ? strlen(key_format_default) : strlen(format);
626 decrypted_datalen = dlen;
627 payload_datalen = decrypted_datalen;
628 if (format) {
629 if (!strcmp(format, key_format_ecryptfs)) {
630 if (dlen != ECRYPTFS_MAX_KEY_BYTES) {
631 pr_err("encrypted_key: keylen for the ecryptfs format must be equal to %d bytes\n",
632 ECRYPTFS_MAX_KEY_BYTES);
633 return ERR_PTR(-EINVAL);
634 }
635 decrypted_datalen = ECRYPTFS_MAX_KEY_BYTES;
636 payload_datalen = sizeof(struct ecryptfs_auth_tok);
637 } else if (!strcmp(format, key_format_enc32)) {
638 if (decrypted_datalen != KEY_ENC32_PAYLOAD_LEN) {
639 pr_err("encrypted_key: enc32 key payload incorrect length: %d\n",
640 decrypted_datalen);
641 return ERR_PTR(-EINVAL);
642 }
643 }
644 }
645
646 encrypted_datalen = roundup(decrypted_datalen, blksize);
647
648 datablob_len = format_len + 1 + strlen(master_desc) + 1
649 + strlen(datalen) + 1 + ivsize + 1 + encrypted_datalen;
650
651 ret = key_payload_reserve(key, payload_datalen + datablob_len
652 + HASH_SIZE + 1);
653 if (ret < 0)
654 return ERR_PTR(ret);
655
656 epayload = kzalloc(sizeof(*epayload) + payload_datalen +
657 datablob_len + HASH_SIZE + 1, GFP_KERNEL);
658 if (!epayload)
659 return ERR_PTR(-ENOMEM);
660
661 epayload->payload_datalen = payload_datalen;
662 epayload->decrypted_datalen = decrypted_datalen;
663 epayload->datablob_len = datablob_len;
664 return epayload;
665 }
666
667 static int encrypted_key_decrypt(struct encrypted_key_payload *epayload,
668 const char *format, const char *hex_encoded_iv)
669 {
670 struct key *mkey;
671 u8 derived_key[HASH_SIZE];
672 const u8 *master_key;
673 u8 *hmac;
674 const char *hex_encoded_data;
675 unsigned int encrypted_datalen;
676 size_t master_keylen;
677 size_t asciilen;
678 int ret;
679
680 encrypted_datalen = roundup(epayload->decrypted_datalen, blksize);
681 asciilen = (ivsize + 1 + encrypted_datalen + HASH_SIZE) * 2;
682 if (strlen(hex_encoded_iv) != asciilen)
683 return -EINVAL;
684
685 hex_encoded_data = hex_encoded_iv + (2 * ivsize) + 2;
686 ret = hex2bin(epayload->iv, hex_encoded_iv, ivsize);
687 if (ret < 0)
688 return -EINVAL;
689 ret = hex2bin(epayload->encrypted_data, hex_encoded_data,
690 encrypted_datalen);
691 if (ret < 0)
692 return -EINVAL;
693
694 hmac = epayload->format + epayload->datablob_len;
695 ret = hex2bin(hmac, hex_encoded_data + (encrypted_datalen * 2),
696 HASH_SIZE);
697 if (ret < 0)
698 return -EINVAL;
699
700 mkey = request_master_key(epayload, &master_key, &master_keylen);
701 if (IS_ERR(mkey))
702 return PTR_ERR(mkey);
703
704 ret = datablob_hmac_verify(epayload, format, master_key, master_keylen);
705 if (ret < 0) {
706 pr_err("encrypted_key: bad hmac (%d)\n", ret);
707 goto out;
708 }
709
710 ret = get_derived_key(derived_key, ENC_KEY, master_key, master_keylen);
711 if (ret < 0)
712 goto out;
713
714 ret = derived_key_decrypt(epayload, derived_key, sizeof derived_key);
715 if (ret < 0)
716 pr_err("encrypted_key: failed to decrypt key (%d)\n", ret);
717 out:
718 up_read(&mkey->sem);
719 key_put(mkey);
720 memzero_explicit(derived_key, sizeof(derived_key));
721 return ret;
722 }
723
724 static void __ekey_init(struct encrypted_key_payload *epayload,
725 const char *format, const char *master_desc,
726 const char *datalen)
727 {
728 unsigned int format_len;
729
730 format_len = (!format) ? strlen(key_format_default) : strlen(format);
731 epayload->format = epayload->payload_data + epayload->payload_datalen;
732 epayload->master_desc = epayload->format + format_len + 1;
733 epayload->datalen = epayload->master_desc + strlen(master_desc) + 1;
734 epayload->iv = epayload->datalen + strlen(datalen) + 1;
735 epayload->encrypted_data = epayload->iv + ivsize + 1;
736 epayload->decrypted_data = epayload->payload_data;
737
738 if (!format)
739 memcpy(epayload->format, key_format_default, format_len);
740 else {
741 if (!strcmp(format, key_format_ecryptfs))
742 epayload->decrypted_data =
743 ecryptfs_get_auth_tok_key((struct ecryptfs_auth_tok *)epayload->payload_data);
744
745 memcpy(epayload->format, format, format_len);
746 }
747
748 memcpy(epayload->master_desc, master_desc, strlen(master_desc));
749 memcpy(epayload->datalen, datalen, strlen(datalen));
750 }
751
752
753
754
755
756
757
758 static int encrypted_init(struct encrypted_key_payload *epayload,
759 const char *key_desc, const char *format,
760 const char *master_desc, const char *datalen,
761 const char *hex_encoded_iv)
762 {
763 int ret = 0;
764
765 if (format && !strcmp(format, key_format_ecryptfs)) {
766 ret = valid_ecryptfs_desc(key_desc);
767 if (ret < 0)
768 return ret;
769
770 ecryptfs_fill_auth_tok((struct ecryptfs_auth_tok *)epayload->payload_data,
771 key_desc);
772 }
773
774 __ekey_init(epayload, format, master_desc, datalen);
775 if (!hex_encoded_iv) {
776 get_random_bytes(epayload->iv, ivsize);
777
778 get_random_bytes(epayload->decrypted_data,
779 epayload->decrypted_datalen);
780 } else
781 ret = encrypted_key_decrypt(epayload, format, hex_encoded_iv);
782 return ret;
783 }
784
785
786
787
788
789
790
791
792
793 static int encrypted_instantiate(struct key *key,
794 struct key_preparsed_payload *prep)
795 {
796 struct encrypted_key_payload *epayload = NULL;
797 char *datablob = NULL;
798 const char *format = NULL;
799 char *master_desc = NULL;
800 char *decrypted_datalen = NULL;
801 char *hex_encoded_iv = NULL;
802 size_t datalen = prep->datalen;
803 int ret;
804
805 if (datalen <= 0 || datalen > 32767 || !prep->data)
806 return -EINVAL;
807
808 datablob = kmalloc(datalen + 1, GFP_KERNEL);
809 if (!datablob)
810 return -ENOMEM;
811 datablob[datalen] = 0;
812 memcpy(datablob, prep->data, datalen);
813 ret = datablob_parse(datablob, &format, &master_desc,
814 &decrypted_datalen, &hex_encoded_iv);
815 if (ret < 0)
816 goto out;
817
818 epayload = encrypted_key_alloc(key, format, master_desc,
819 decrypted_datalen);
820 if (IS_ERR(epayload)) {
821 ret = PTR_ERR(epayload);
822 goto out;
823 }
824 ret = encrypted_init(epayload, key->description, format, master_desc,
825 decrypted_datalen, hex_encoded_iv);
826 if (ret < 0) {
827 kzfree(epayload);
828 goto out;
829 }
830
831 rcu_assign_keypointer(key, epayload);
832 out:
833 kzfree(datablob);
834 return ret;
835 }
836
837 static void encrypted_rcu_free(struct rcu_head *rcu)
838 {
839 struct encrypted_key_payload *epayload;
840
841 epayload = container_of(rcu, struct encrypted_key_payload, rcu);
842 kzfree(epayload);
843 }
844
845
846
847
848
849
850
851
852
853
854 static int encrypted_update(struct key *key, struct key_preparsed_payload *prep)
855 {
856 struct encrypted_key_payload *epayload = key->payload.data[0];
857 struct encrypted_key_payload *new_epayload;
858 char *buf;
859 char *new_master_desc = NULL;
860 const char *format = NULL;
861 size_t datalen = prep->datalen;
862 int ret = 0;
863
864 if (key_is_negative(key))
865 return -ENOKEY;
866 if (datalen <= 0 || datalen > 32767 || !prep->data)
867 return -EINVAL;
868
869 buf = kmalloc(datalen + 1, GFP_KERNEL);
870 if (!buf)
871 return -ENOMEM;
872
873 buf[datalen] = 0;
874 memcpy(buf, prep->data, datalen);
875 ret = datablob_parse(buf, &format, &new_master_desc, NULL, NULL);
876 if (ret < 0)
877 goto out;
878
879 ret = valid_master_desc(new_master_desc, epayload->master_desc);
880 if (ret < 0)
881 goto out;
882
883 new_epayload = encrypted_key_alloc(key, epayload->format,
884 new_master_desc, epayload->datalen);
885 if (IS_ERR(new_epayload)) {
886 ret = PTR_ERR(new_epayload);
887 goto out;
888 }
889
890 __ekey_init(new_epayload, epayload->format, new_master_desc,
891 epayload->datalen);
892
893 memcpy(new_epayload->iv, epayload->iv, ivsize);
894 memcpy(new_epayload->payload_data, epayload->payload_data,
895 epayload->payload_datalen);
896
897 rcu_assign_keypointer(key, new_epayload);
898 call_rcu(&epayload->rcu, encrypted_rcu_free);
899 out:
900 kzfree(buf);
901 return ret;
902 }
903
904
905
906
907
908
909
910
911
912 static long encrypted_read(const struct key *key, char *buffer,
913 size_t buflen)
914 {
915 struct encrypted_key_payload *epayload;
916 struct key *mkey;
917 const u8 *master_key;
918 size_t master_keylen;
919 char derived_key[HASH_SIZE];
920 char *ascii_buf;
921 size_t asciiblob_len;
922 int ret;
923
924 epayload = dereference_key_locked(key);
925
926
927 asciiblob_len = epayload->datablob_len + ivsize + 1
928 + roundup(epayload->decrypted_datalen, blksize)
929 + (HASH_SIZE * 2);
930
931 if (!buffer || buflen < asciiblob_len)
932 return asciiblob_len;
933
934 mkey = request_master_key(epayload, &master_key, &master_keylen);
935 if (IS_ERR(mkey))
936 return PTR_ERR(mkey);
937
938 ret = get_derived_key(derived_key, ENC_KEY, master_key, master_keylen);
939 if (ret < 0)
940 goto out;
941
942 ret = derived_key_encrypt(epayload, derived_key, sizeof derived_key);
943 if (ret < 0)
944 goto out;
945
946 ret = datablob_hmac_append(epayload, master_key, master_keylen);
947 if (ret < 0)
948 goto out;
949
950 ascii_buf = datablob_format(epayload, asciiblob_len);
951 if (!ascii_buf) {
952 ret = -ENOMEM;
953 goto out;
954 }
955
956 up_read(&mkey->sem);
957 key_put(mkey);
958 memzero_explicit(derived_key, sizeof(derived_key));
959
960 memcpy(buffer, ascii_buf, asciiblob_len);
961 kzfree(ascii_buf);
962
963 return asciiblob_len;
964 out:
965 up_read(&mkey->sem);
966 key_put(mkey);
967 memzero_explicit(derived_key, sizeof(derived_key));
968 return ret;
969 }
970
971
972
973
974 static void encrypted_destroy(struct key *key)
975 {
976 kzfree(key->payload.data[0]);
977 }
978
979 struct key_type key_type_encrypted = {
980 .name = "encrypted",
981 .instantiate = encrypted_instantiate,
982 .update = encrypted_update,
983 .destroy = encrypted_destroy,
984 .describe = user_describe,
985 .read = encrypted_read,
986 };
987 EXPORT_SYMBOL_GPL(key_type_encrypted);
988
989 static int __init init_encrypted(void)
990 {
991 int ret;
992
993 hash_tfm = crypto_alloc_shash(hash_alg, 0, 0);
994 if (IS_ERR(hash_tfm)) {
995 pr_err("encrypted_key: can't allocate %s transform: %ld\n",
996 hash_alg, PTR_ERR(hash_tfm));
997 return PTR_ERR(hash_tfm);
998 }
999
1000 ret = aes_get_sizes();
1001 if (ret < 0)
1002 goto out;
1003 ret = register_key_type(&key_type_encrypted);
1004 if (ret < 0)
1005 goto out;
1006 return 0;
1007 out:
1008 crypto_free_shash(hash_tfm);
1009 return ret;
1010
1011 }
1012
1013 static void __exit cleanup_encrypted(void)
1014 {
1015 crypto_free_shash(hash_tfm);
1016 unregister_key_type(&key_type_encrypted);
1017 }
1018
1019 late_initcall(init_encrypted);
1020 module_exit(cleanup_encrypted);
1021
1022 MODULE_LICENSE("GPL");