Root/
1 | /* |
2 | * Copyright (C) 2010 IBM Corporation |
3 | * |
4 | * Author: |
5 | * David Safford <safford@us.ibm.com> |
6 | * |
7 | * This program is free software; you can redistribute it and/or modify |
8 | * it under the terms of the GNU General Public License as published by |
9 | * the Free Software Foundation, version 2 of the License. |
10 | * |
11 | * See Documentation/security/keys-trusted-encrypted.txt |
12 | */ |
13 | |
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 <linux/key-type.h> |
24 | #include <linux/rcupdate.h> |
25 | #include <linux/crypto.h> |
26 | #include <crypto/hash.h> |
27 | #include <crypto/sha.h> |
28 | #include <linux/capability.h> |
29 | #include <linux/tpm.h> |
30 | #include <linux/tpm_command.h> |
31 | |
32 | #include "trusted.h" |
33 | |
34 | static const char hmac_alg[] = "hmac(sha1)"; |
35 | static const char hash_alg[] = "sha1"; |
36 | |
37 | struct sdesc { |
38 | struct shash_desc shash; |
39 | char ctx[]; |
40 | }; |
41 | |
42 | static struct crypto_shash *hashalg; |
43 | static struct crypto_shash *hmacalg; |
44 | |
45 | static struct sdesc *init_sdesc(struct crypto_shash *alg) |
46 | { |
47 | struct sdesc *sdesc; |
48 | int size; |
49 | |
50 | size = sizeof(struct shash_desc) + crypto_shash_descsize(alg); |
51 | sdesc = kmalloc(size, GFP_KERNEL); |
52 | if (!sdesc) |
53 | return ERR_PTR(-ENOMEM); |
54 | sdesc->shash.tfm = alg; |
55 | sdesc->shash.flags = 0x0; |
56 | return sdesc; |
57 | } |
58 | |
59 | static int TSS_sha1(const unsigned char *data, unsigned int datalen, |
60 | unsigned char *digest) |
61 | { |
62 | struct sdesc *sdesc; |
63 | int ret; |
64 | |
65 | sdesc = init_sdesc(hashalg); |
66 | if (IS_ERR(sdesc)) { |
67 | pr_info("trusted_key: can't alloc %s\n", hash_alg); |
68 | return PTR_ERR(sdesc); |
69 | } |
70 | |
71 | ret = crypto_shash_digest(&sdesc->shash, data, datalen, digest); |
72 | kfree(sdesc); |
73 | return ret; |
74 | } |
75 | |
76 | static int TSS_rawhmac(unsigned char *digest, const unsigned char *key, |
77 | unsigned int keylen, ...) |
78 | { |
79 | struct sdesc *sdesc; |
80 | va_list argp; |
81 | unsigned int dlen; |
82 | unsigned char *data; |
83 | int ret; |
84 | |
85 | sdesc = init_sdesc(hmacalg); |
86 | if (IS_ERR(sdesc)) { |
87 | pr_info("trusted_key: can't alloc %s\n", hmac_alg); |
88 | return PTR_ERR(sdesc); |
89 | } |
90 | |
91 | ret = crypto_shash_setkey(hmacalg, key, keylen); |
92 | if (ret < 0) |
93 | goto out; |
94 | ret = crypto_shash_init(&sdesc->shash); |
95 | if (ret < 0) |
96 | goto out; |
97 | |
98 | va_start(argp, keylen); |
99 | for (;;) { |
100 | dlen = va_arg(argp, unsigned int); |
101 | if (dlen == 0) |
102 | break; |
103 | data = va_arg(argp, unsigned char *); |
104 | if (data == NULL) { |
105 | ret = -EINVAL; |
106 | break; |
107 | } |
108 | ret = crypto_shash_update(&sdesc->shash, data, dlen); |
109 | if (ret < 0) |
110 | break; |
111 | } |
112 | va_end(argp); |
113 | if (!ret) |
114 | ret = crypto_shash_final(&sdesc->shash, digest); |
115 | out: |
116 | kfree(sdesc); |
117 | return ret; |
118 | } |
119 | |
120 | /* |
121 | * calculate authorization info fields to send to TPM |
122 | */ |
123 | static int TSS_authhmac(unsigned char *digest, const unsigned char *key, |
124 | unsigned int keylen, unsigned char *h1, |
125 | unsigned char *h2, unsigned char h3, ...) |
126 | { |
127 | unsigned char paramdigest[SHA1_DIGEST_SIZE]; |
128 | struct sdesc *sdesc; |
129 | unsigned int dlen; |
130 | unsigned char *data; |
131 | unsigned char c; |
132 | int ret; |
133 | va_list argp; |
134 | |
135 | sdesc = init_sdesc(hashalg); |
136 | if (IS_ERR(sdesc)) { |
137 | pr_info("trusted_key: can't alloc %s\n", hash_alg); |
138 | return PTR_ERR(sdesc); |
139 | } |
140 | |
141 | c = h3; |
142 | ret = crypto_shash_init(&sdesc->shash); |
143 | if (ret < 0) |
144 | goto out; |
145 | va_start(argp, h3); |
146 | for (;;) { |
147 | dlen = va_arg(argp, unsigned int); |
148 | if (dlen == 0) |
149 | break; |
150 | data = va_arg(argp, unsigned char *); |
151 | if (!data) { |
152 | ret = -EINVAL; |
153 | break; |
154 | } |
155 | ret = crypto_shash_update(&sdesc->shash, data, dlen); |
156 | if (ret < 0) |
157 | break; |
158 | } |
159 | va_end(argp); |
160 | if (!ret) |
161 | ret = crypto_shash_final(&sdesc->shash, paramdigest); |
162 | if (!ret) |
163 | ret = TSS_rawhmac(digest, key, keylen, SHA1_DIGEST_SIZE, |
164 | paramdigest, TPM_NONCE_SIZE, h1, |
165 | TPM_NONCE_SIZE, h2, 1, &c, 0, 0); |
166 | out: |
167 | kfree(sdesc); |
168 | return ret; |
169 | } |
170 | |
171 | /* |
172 | * verify the AUTH1_COMMAND (Seal) result from TPM |
173 | */ |
174 | static int TSS_checkhmac1(unsigned char *buffer, |
175 | const uint32_t command, |
176 | const unsigned char *ononce, |
177 | const unsigned char *key, |
178 | unsigned int keylen, ...) |
179 | { |
180 | uint32_t bufsize; |
181 | uint16_t tag; |
182 | uint32_t ordinal; |
183 | uint32_t result; |
184 | unsigned char *enonce; |
185 | unsigned char *continueflag; |
186 | unsigned char *authdata; |
187 | unsigned char testhmac[SHA1_DIGEST_SIZE]; |
188 | unsigned char paramdigest[SHA1_DIGEST_SIZE]; |
189 | struct sdesc *sdesc; |
190 | unsigned int dlen; |
191 | unsigned int dpos; |
192 | va_list argp; |
193 | int ret; |
194 | |
195 | bufsize = LOAD32(buffer, TPM_SIZE_OFFSET); |
196 | tag = LOAD16(buffer, 0); |
197 | ordinal = command; |
198 | result = LOAD32N(buffer, TPM_RETURN_OFFSET); |
199 | if (tag == TPM_TAG_RSP_COMMAND) |
200 | return 0; |
201 | if (tag != TPM_TAG_RSP_AUTH1_COMMAND) |
202 | return -EINVAL; |
203 | authdata = buffer + bufsize - SHA1_DIGEST_SIZE; |
204 | continueflag = authdata - 1; |
205 | enonce = continueflag - TPM_NONCE_SIZE; |
206 | |
207 | sdesc = init_sdesc(hashalg); |
208 | if (IS_ERR(sdesc)) { |
209 | pr_info("trusted_key: can't alloc %s\n", hash_alg); |
210 | return PTR_ERR(sdesc); |
211 | } |
212 | ret = crypto_shash_init(&sdesc->shash); |
213 | if (ret < 0) |
214 | goto out; |
215 | ret = crypto_shash_update(&sdesc->shash, (const u8 *)&result, |
216 | sizeof result); |
217 | if (ret < 0) |
218 | goto out; |
219 | ret = crypto_shash_update(&sdesc->shash, (const u8 *)&ordinal, |
220 | sizeof ordinal); |
221 | if (ret < 0) |
222 | goto out; |
223 | va_start(argp, keylen); |
224 | for (;;) { |
225 | dlen = va_arg(argp, unsigned int); |
226 | if (dlen == 0) |
227 | break; |
228 | dpos = va_arg(argp, unsigned int); |
229 | ret = crypto_shash_update(&sdesc->shash, buffer + dpos, dlen); |
230 | if (ret < 0) |
231 | break; |
232 | } |
233 | va_end(argp); |
234 | if (!ret) |
235 | ret = crypto_shash_final(&sdesc->shash, paramdigest); |
236 | if (ret < 0) |
237 | goto out; |
238 | |
239 | ret = TSS_rawhmac(testhmac, key, keylen, SHA1_DIGEST_SIZE, paramdigest, |
240 | TPM_NONCE_SIZE, enonce, TPM_NONCE_SIZE, ononce, |
241 | 1, continueflag, 0, 0); |
242 | if (ret < 0) |
243 | goto out; |
244 | |
245 | if (memcmp(testhmac, authdata, SHA1_DIGEST_SIZE)) |
246 | ret = -EINVAL; |
247 | out: |
248 | kfree(sdesc); |
249 | return ret; |
250 | } |
251 | |
252 | /* |
253 | * verify the AUTH2_COMMAND (unseal) result from TPM |
254 | */ |
255 | static int TSS_checkhmac2(unsigned char *buffer, |
256 | const uint32_t command, |
257 | const unsigned char *ononce, |
258 | const unsigned char *key1, |
259 | unsigned int keylen1, |
260 | const unsigned char *key2, |
261 | unsigned int keylen2, ...) |
262 | { |
263 | uint32_t bufsize; |
264 | uint16_t tag; |
265 | uint32_t ordinal; |
266 | uint32_t result; |
267 | unsigned char *enonce1; |
268 | unsigned char *continueflag1; |
269 | unsigned char *authdata1; |
270 | unsigned char *enonce2; |
271 | unsigned char *continueflag2; |
272 | unsigned char *authdata2; |
273 | unsigned char testhmac1[SHA1_DIGEST_SIZE]; |
274 | unsigned char testhmac2[SHA1_DIGEST_SIZE]; |
275 | unsigned char paramdigest[SHA1_DIGEST_SIZE]; |
276 | struct sdesc *sdesc; |
277 | unsigned int dlen; |
278 | unsigned int dpos; |
279 | va_list argp; |
280 | int ret; |
281 | |
282 | bufsize = LOAD32(buffer, TPM_SIZE_OFFSET); |
283 | tag = LOAD16(buffer, 0); |
284 | ordinal = command; |
285 | result = LOAD32N(buffer, TPM_RETURN_OFFSET); |
286 | |
287 | if (tag == TPM_TAG_RSP_COMMAND) |
288 | return 0; |
289 | if (tag != TPM_TAG_RSP_AUTH2_COMMAND) |
290 | return -EINVAL; |
291 | authdata1 = buffer + bufsize - (SHA1_DIGEST_SIZE + 1 |
292 | + SHA1_DIGEST_SIZE + SHA1_DIGEST_SIZE); |
293 | authdata2 = buffer + bufsize - (SHA1_DIGEST_SIZE); |
294 | continueflag1 = authdata1 - 1; |
295 | continueflag2 = authdata2 - 1; |
296 | enonce1 = continueflag1 - TPM_NONCE_SIZE; |
297 | enonce2 = continueflag2 - TPM_NONCE_SIZE; |
298 | |
299 | sdesc = init_sdesc(hashalg); |
300 | if (IS_ERR(sdesc)) { |
301 | pr_info("trusted_key: can't alloc %s\n", hash_alg); |
302 | return PTR_ERR(sdesc); |
303 | } |
304 | ret = crypto_shash_init(&sdesc->shash); |
305 | if (ret < 0) |
306 | goto out; |
307 | ret = crypto_shash_update(&sdesc->shash, (const u8 *)&result, |
308 | sizeof result); |
309 | if (ret < 0) |
310 | goto out; |
311 | ret = crypto_shash_update(&sdesc->shash, (const u8 *)&ordinal, |
312 | sizeof ordinal); |
313 | if (ret < 0) |
314 | goto out; |
315 | |
316 | va_start(argp, keylen2); |
317 | for (;;) { |
318 | dlen = va_arg(argp, unsigned int); |
319 | if (dlen == 0) |
320 | break; |
321 | dpos = va_arg(argp, unsigned int); |
322 | ret = crypto_shash_update(&sdesc->shash, buffer + dpos, dlen); |
323 | if (ret < 0) |
324 | break; |
325 | } |
326 | va_end(argp); |
327 | if (!ret) |
328 | ret = crypto_shash_final(&sdesc->shash, paramdigest); |
329 | if (ret < 0) |
330 | goto out; |
331 | |
332 | ret = TSS_rawhmac(testhmac1, key1, keylen1, SHA1_DIGEST_SIZE, |
333 | paramdigest, TPM_NONCE_SIZE, enonce1, |
334 | TPM_NONCE_SIZE, ononce, 1, continueflag1, 0, 0); |
335 | if (ret < 0) |
336 | goto out; |
337 | if (memcmp(testhmac1, authdata1, SHA1_DIGEST_SIZE)) { |
338 | ret = -EINVAL; |
339 | goto out; |
340 | } |
341 | ret = TSS_rawhmac(testhmac2, key2, keylen2, SHA1_DIGEST_SIZE, |
342 | paramdigest, TPM_NONCE_SIZE, enonce2, |
343 | TPM_NONCE_SIZE, ononce, 1, continueflag2, 0, 0); |
344 | if (ret < 0) |
345 | goto out; |
346 | if (memcmp(testhmac2, authdata2, SHA1_DIGEST_SIZE)) |
347 | ret = -EINVAL; |
348 | out: |
349 | kfree(sdesc); |
350 | return ret; |
351 | } |
352 | |
353 | /* |
354 | * For key specific tpm requests, we will generate and send our |
355 | * own TPM command packets using the drivers send function. |
356 | */ |
357 | static int trusted_tpm_send(const u32 chip_num, unsigned char *cmd, |
358 | size_t buflen) |
359 | { |
360 | int rc; |
361 | |
362 | dump_tpm_buf(cmd); |
363 | rc = tpm_send(chip_num, cmd, buflen); |
364 | dump_tpm_buf(cmd); |
365 | if (rc > 0) |
366 | /* Can't return positive return codes values to keyctl */ |
367 | rc = -EPERM; |
368 | return rc; |
369 | } |
370 | |
371 | /* |
372 | * Lock a trusted key, by extending a selected PCR. |
373 | * |
374 | * Prevents a trusted key that is sealed to PCRs from being accessed. |
375 | * This uses the tpm driver's extend function. |
376 | */ |
377 | static int pcrlock(const int pcrnum) |
378 | { |
379 | unsigned char hash[SHA1_DIGEST_SIZE]; |
380 | int ret; |
381 | |
382 | if (!capable(CAP_SYS_ADMIN)) |
383 | return -EPERM; |
384 | ret = tpm_get_random(TPM_ANY_NUM, hash, SHA1_DIGEST_SIZE); |
385 | if (ret != SHA1_DIGEST_SIZE) |
386 | return ret; |
387 | return tpm_pcr_extend(TPM_ANY_NUM, pcrnum, hash) ? -EINVAL : 0; |
388 | } |
389 | |
390 | /* |
391 | * Create an object specific authorisation protocol (OSAP) session |
392 | */ |
393 | static int osap(struct tpm_buf *tb, struct osapsess *s, |
394 | const unsigned char *key, uint16_t type, uint32_t handle) |
395 | { |
396 | unsigned char enonce[TPM_NONCE_SIZE]; |
397 | unsigned char ononce[TPM_NONCE_SIZE]; |
398 | int ret; |
399 | |
400 | ret = tpm_get_random(TPM_ANY_NUM, ononce, TPM_NONCE_SIZE); |
401 | if (ret != TPM_NONCE_SIZE) |
402 | return ret; |
403 | |
404 | INIT_BUF(tb); |
405 | store16(tb, TPM_TAG_RQU_COMMAND); |
406 | store32(tb, TPM_OSAP_SIZE); |
407 | store32(tb, TPM_ORD_OSAP); |
408 | store16(tb, type); |
409 | store32(tb, handle); |
410 | storebytes(tb, ononce, TPM_NONCE_SIZE); |
411 | |
412 | ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE); |
413 | if (ret < 0) |
414 | return ret; |
415 | |
416 | s->handle = LOAD32(tb->data, TPM_DATA_OFFSET); |
417 | memcpy(s->enonce, &(tb->data[TPM_DATA_OFFSET + sizeof(uint32_t)]), |
418 | TPM_NONCE_SIZE); |
419 | memcpy(enonce, &(tb->data[TPM_DATA_OFFSET + sizeof(uint32_t) + |
420 | TPM_NONCE_SIZE]), TPM_NONCE_SIZE); |
421 | return TSS_rawhmac(s->secret, key, SHA1_DIGEST_SIZE, TPM_NONCE_SIZE, |
422 | enonce, TPM_NONCE_SIZE, ononce, 0, 0); |
423 | } |
424 | |
425 | /* |
426 | * Create an object independent authorisation protocol (oiap) session |
427 | */ |
428 | static int oiap(struct tpm_buf *tb, uint32_t *handle, unsigned char *nonce) |
429 | { |
430 | int ret; |
431 | |
432 | INIT_BUF(tb); |
433 | store16(tb, TPM_TAG_RQU_COMMAND); |
434 | store32(tb, TPM_OIAP_SIZE); |
435 | store32(tb, TPM_ORD_OIAP); |
436 | ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE); |
437 | if (ret < 0) |
438 | return ret; |
439 | |
440 | *handle = LOAD32(tb->data, TPM_DATA_OFFSET); |
441 | memcpy(nonce, &tb->data[TPM_DATA_OFFSET + sizeof(uint32_t)], |
442 | TPM_NONCE_SIZE); |
443 | return 0; |
444 | } |
445 | |
446 | struct tpm_digests { |
447 | unsigned char encauth[SHA1_DIGEST_SIZE]; |
448 | unsigned char pubauth[SHA1_DIGEST_SIZE]; |
449 | unsigned char xorwork[SHA1_DIGEST_SIZE * 2]; |
450 | unsigned char xorhash[SHA1_DIGEST_SIZE]; |
451 | unsigned char nonceodd[TPM_NONCE_SIZE]; |
452 | }; |
453 | |
454 | /* |
455 | * Have the TPM seal(encrypt) the trusted key, possibly based on |
456 | * Platform Configuration Registers (PCRs). AUTH1 for sealing key. |
457 | */ |
458 | static int tpm_seal(struct tpm_buf *tb, uint16_t keytype, |
459 | uint32_t keyhandle, const unsigned char *keyauth, |
460 | const unsigned char *data, uint32_t datalen, |
461 | unsigned char *blob, uint32_t *bloblen, |
462 | const unsigned char *blobauth, |
463 | const unsigned char *pcrinfo, uint32_t pcrinfosize) |
464 | { |
465 | struct osapsess sess; |
466 | struct tpm_digests *td; |
467 | unsigned char cont; |
468 | uint32_t ordinal; |
469 | uint32_t pcrsize; |
470 | uint32_t datsize; |
471 | int sealinfosize; |
472 | int encdatasize; |
473 | int storedsize; |
474 | int ret; |
475 | int i; |
476 | |
477 | /* alloc some work space for all the hashes */ |
478 | td = kmalloc(sizeof *td, GFP_KERNEL); |
479 | if (!td) |
480 | return -ENOMEM; |
481 | |
482 | /* get session for sealing key */ |
483 | ret = osap(tb, &sess, keyauth, keytype, keyhandle); |
484 | if (ret < 0) |
485 | goto out; |
486 | dump_sess(&sess); |
487 | |
488 | /* calculate encrypted authorization value */ |
489 | memcpy(td->xorwork, sess.secret, SHA1_DIGEST_SIZE); |
490 | memcpy(td->xorwork + SHA1_DIGEST_SIZE, sess.enonce, SHA1_DIGEST_SIZE); |
491 | ret = TSS_sha1(td->xorwork, SHA1_DIGEST_SIZE * 2, td->xorhash); |
492 | if (ret < 0) |
493 | goto out; |
494 | |
495 | ret = tpm_get_random(TPM_ANY_NUM, td->nonceodd, TPM_NONCE_SIZE); |
496 | if (ret != TPM_NONCE_SIZE) |
497 | goto out; |
498 | ordinal = htonl(TPM_ORD_SEAL); |
499 | datsize = htonl(datalen); |
500 | pcrsize = htonl(pcrinfosize); |
501 | cont = 0; |
502 | |
503 | /* encrypt data authorization key */ |
504 | for (i = 0; i < SHA1_DIGEST_SIZE; ++i) |
505 | td->encauth[i] = td->xorhash[i] ^ blobauth[i]; |
506 | |
507 | /* calculate authorization HMAC value */ |
508 | if (pcrinfosize == 0) { |
509 | /* no pcr info specified */ |
510 | ret = TSS_authhmac(td->pubauth, sess.secret, SHA1_DIGEST_SIZE, |
511 | sess.enonce, td->nonceodd, cont, |
512 | sizeof(uint32_t), &ordinal, SHA1_DIGEST_SIZE, |
513 | td->encauth, sizeof(uint32_t), &pcrsize, |
514 | sizeof(uint32_t), &datsize, datalen, data, 0, |
515 | 0); |
516 | } else { |
517 | /* pcr info specified */ |
518 | ret = TSS_authhmac(td->pubauth, sess.secret, SHA1_DIGEST_SIZE, |
519 | sess.enonce, td->nonceodd, cont, |
520 | sizeof(uint32_t), &ordinal, SHA1_DIGEST_SIZE, |
521 | td->encauth, sizeof(uint32_t), &pcrsize, |
522 | pcrinfosize, pcrinfo, sizeof(uint32_t), |
523 | &datsize, datalen, data, 0, 0); |
524 | } |
525 | if (ret < 0) |
526 | goto out; |
527 | |
528 | /* build and send the TPM request packet */ |
529 | INIT_BUF(tb); |
530 | store16(tb, TPM_TAG_RQU_AUTH1_COMMAND); |
531 | store32(tb, TPM_SEAL_SIZE + pcrinfosize + datalen); |
532 | store32(tb, TPM_ORD_SEAL); |
533 | store32(tb, keyhandle); |
534 | storebytes(tb, td->encauth, SHA1_DIGEST_SIZE); |
535 | store32(tb, pcrinfosize); |
536 | storebytes(tb, pcrinfo, pcrinfosize); |
537 | store32(tb, datalen); |
538 | storebytes(tb, data, datalen); |
539 | store32(tb, sess.handle); |
540 | storebytes(tb, td->nonceodd, TPM_NONCE_SIZE); |
541 | store8(tb, cont); |
542 | storebytes(tb, td->pubauth, SHA1_DIGEST_SIZE); |
543 | |
544 | ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE); |
545 | if (ret < 0) |
546 | goto out; |
547 | |
548 | /* calculate the size of the returned Blob */ |
549 | sealinfosize = LOAD32(tb->data, TPM_DATA_OFFSET + sizeof(uint32_t)); |
550 | encdatasize = LOAD32(tb->data, TPM_DATA_OFFSET + sizeof(uint32_t) + |
551 | sizeof(uint32_t) + sealinfosize); |
552 | storedsize = sizeof(uint32_t) + sizeof(uint32_t) + sealinfosize + |
553 | sizeof(uint32_t) + encdatasize; |
554 | |
555 | /* check the HMAC in the response */ |
556 | ret = TSS_checkhmac1(tb->data, ordinal, td->nonceodd, sess.secret, |
557 | SHA1_DIGEST_SIZE, storedsize, TPM_DATA_OFFSET, 0, |
558 | 0); |
559 | |
560 | /* copy the returned blob to caller */ |
561 | if (!ret) { |
562 | memcpy(blob, tb->data + TPM_DATA_OFFSET, storedsize); |
563 | *bloblen = storedsize; |
564 | } |
565 | out: |
566 | kfree(td); |
567 | return ret; |
568 | } |
569 | |
570 | /* |
571 | * use the AUTH2_COMMAND form of unseal, to authorize both key and blob |
572 | */ |
573 | static int tpm_unseal(struct tpm_buf *tb, |
574 | uint32_t keyhandle, const unsigned char *keyauth, |
575 | const unsigned char *blob, int bloblen, |
576 | const unsigned char *blobauth, |
577 | unsigned char *data, unsigned int *datalen) |
578 | { |
579 | unsigned char nonceodd[TPM_NONCE_SIZE]; |
580 | unsigned char enonce1[TPM_NONCE_SIZE]; |
581 | unsigned char enonce2[TPM_NONCE_SIZE]; |
582 | unsigned char authdata1[SHA1_DIGEST_SIZE]; |
583 | unsigned char authdata2[SHA1_DIGEST_SIZE]; |
584 | uint32_t authhandle1 = 0; |
585 | uint32_t authhandle2 = 0; |
586 | unsigned char cont = 0; |
587 | uint32_t ordinal; |
588 | uint32_t keyhndl; |
589 | int ret; |
590 | |
591 | /* sessions for unsealing key and data */ |
592 | ret = oiap(tb, &authhandle1, enonce1); |
593 | if (ret < 0) { |
594 | pr_info("trusted_key: oiap failed (%d)\n", ret); |
595 | return ret; |
596 | } |
597 | ret = oiap(tb, &authhandle2, enonce2); |
598 | if (ret < 0) { |
599 | pr_info("trusted_key: oiap failed (%d)\n", ret); |
600 | return ret; |
601 | } |
602 | |
603 | ordinal = htonl(TPM_ORD_UNSEAL); |
604 | keyhndl = htonl(SRKHANDLE); |
605 | ret = tpm_get_random(TPM_ANY_NUM, nonceodd, TPM_NONCE_SIZE); |
606 | if (ret != TPM_NONCE_SIZE) { |
607 | pr_info("trusted_key: tpm_get_random failed (%d)\n", ret); |
608 | return ret; |
609 | } |
610 | ret = TSS_authhmac(authdata1, keyauth, TPM_NONCE_SIZE, |
611 | enonce1, nonceodd, cont, sizeof(uint32_t), |
612 | &ordinal, bloblen, blob, 0, 0); |
613 | if (ret < 0) |
614 | return ret; |
615 | ret = TSS_authhmac(authdata2, blobauth, TPM_NONCE_SIZE, |
616 | enonce2, nonceodd, cont, sizeof(uint32_t), |
617 | &ordinal, bloblen, blob, 0, 0); |
618 | if (ret < 0) |
619 | return ret; |
620 | |
621 | /* build and send TPM request packet */ |
622 | INIT_BUF(tb); |
623 | store16(tb, TPM_TAG_RQU_AUTH2_COMMAND); |
624 | store32(tb, TPM_UNSEAL_SIZE + bloblen); |
625 | store32(tb, TPM_ORD_UNSEAL); |
626 | store32(tb, keyhandle); |
627 | storebytes(tb, blob, bloblen); |
628 | store32(tb, authhandle1); |
629 | storebytes(tb, nonceodd, TPM_NONCE_SIZE); |
630 | store8(tb, cont); |
631 | storebytes(tb, authdata1, SHA1_DIGEST_SIZE); |
632 | store32(tb, authhandle2); |
633 | storebytes(tb, nonceodd, TPM_NONCE_SIZE); |
634 | store8(tb, cont); |
635 | storebytes(tb, authdata2, SHA1_DIGEST_SIZE); |
636 | |
637 | ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE); |
638 | if (ret < 0) { |
639 | pr_info("trusted_key: authhmac failed (%d)\n", ret); |
640 | return ret; |
641 | } |
642 | |
643 | *datalen = LOAD32(tb->data, TPM_DATA_OFFSET); |
644 | ret = TSS_checkhmac2(tb->data, ordinal, nonceodd, |
645 | keyauth, SHA1_DIGEST_SIZE, |
646 | blobauth, SHA1_DIGEST_SIZE, |
647 | sizeof(uint32_t), TPM_DATA_OFFSET, |
648 | *datalen, TPM_DATA_OFFSET + sizeof(uint32_t), 0, |
649 | 0); |
650 | if (ret < 0) { |
651 | pr_info("trusted_key: TSS_checkhmac2 failed (%d)\n", ret); |
652 | return ret; |
653 | } |
654 | memcpy(data, tb->data + TPM_DATA_OFFSET + sizeof(uint32_t), *datalen); |
655 | return 0; |
656 | } |
657 | |
658 | /* |
659 | * Have the TPM seal(encrypt) the symmetric key |
660 | */ |
661 | static int key_seal(struct trusted_key_payload *p, |
662 | struct trusted_key_options *o) |
663 | { |
664 | struct tpm_buf *tb; |
665 | int ret; |
666 | |
667 | tb = kzalloc(sizeof *tb, GFP_KERNEL); |
668 | if (!tb) |
669 | return -ENOMEM; |
670 | |
671 | /* include migratable flag at end of sealed key */ |
672 | p->key[p->key_len] = p->migratable; |
673 | |
674 | ret = tpm_seal(tb, o->keytype, o->keyhandle, o->keyauth, |
675 | p->key, p->key_len + 1, p->blob, &p->blob_len, |
676 | o->blobauth, o->pcrinfo, o->pcrinfo_len); |
677 | if (ret < 0) |
678 | pr_info("trusted_key: srkseal failed (%d)\n", ret); |
679 | |
680 | kfree(tb); |
681 | return ret; |
682 | } |
683 | |
684 | /* |
685 | * Have the TPM unseal(decrypt) the symmetric key |
686 | */ |
687 | static int key_unseal(struct trusted_key_payload *p, |
688 | struct trusted_key_options *o) |
689 | { |
690 | struct tpm_buf *tb; |
691 | int ret; |
692 | |
693 | tb = kzalloc(sizeof *tb, GFP_KERNEL); |
694 | if (!tb) |
695 | return -ENOMEM; |
696 | |
697 | ret = tpm_unseal(tb, o->keyhandle, o->keyauth, p->blob, p->blob_len, |
698 | o->blobauth, p->key, &p->key_len); |
699 | if (ret < 0) |
700 | pr_info("trusted_key: srkunseal failed (%d)\n", ret); |
701 | else |
702 | /* pull migratable flag out of sealed key */ |
703 | p->migratable = p->key[--p->key_len]; |
704 | |
705 | kfree(tb); |
706 | return ret; |
707 | } |
708 | |
709 | enum { |
710 | Opt_err = -1, |
711 | Opt_new, Opt_load, Opt_update, |
712 | Opt_keyhandle, Opt_keyauth, Opt_blobauth, |
713 | Opt_pcrinfo, Opt_pcrlock, Opt_migratable |
714 | }; |
715 | |
716 | static const match_table_t key_tokens = { |
717 | {Opt_new, "new"}, |
718 | {Opt_load, "load"}, |
719 | {Opt_update, "update"}, |
720 | {Opt_keyhandle, "keyhandle=%s"}, |
721 | {Opt_keyauth, "keyauth=%s"}, |
722 | {Opt_blobauth, "blobauth=%s"}, |
723 | {Opt_pcrinfo, "pcrinfo=%s"}, |
724 | {Opt_pcrlock, "pcrlock=%s"}, |
725 | {Opt_migratable, "migratable=%s"}, |
726 | {Opt_err, NULL} |
727 | }; |
728 | |
729 | /* can have zero or more token= options */ |
730 | static int getoptions(char *c, struct trusted_key_payload *pay, |
731 | struct trusted_key_options *opt) |
732 | { |
733 | substring_t args[MAX_OPT_ARGS]; |
734 | char *p = c; |
735 | int token; |
736 | int res; |
737 | unsigned long handle; |
738 | unsigned long lock; |
739 | |
740 | while ((p = strsep(&c, " \t"))) { |
741 | if (*p == '\0' || *p == ' ' || *p == '\t') |
742 | continue; |
743 | token = match_token(p, key_tokens, args); |
744 | |
745 | switch (token) { |
746 | case Opt_pcrinfo: |
747 | opt->pcrinfo_len = strlen(args[0].from) / 2; |
748 | if (opt->pcrinfo_len > MAX_PCRINFO_SIZE) |
749 | return -EINVAL; |
750 | res = hex2bin(opt->pcrinfo, args[0].from, |
751 | opt->pcrinfo_len); |
752 | if (res < 0) |
753 | return -EINVAL; |
754 | break; |
755 | case Opt_keyhandle: |
756 | res = strict_strtoul(args[0].from, 16, &handle); |
757 | if (res < 0) |
758 | return -EINVAL; |
759 | opt->keytype = SEAL_keytype; |
760 | opt->keyhandle = handle; |
761 | break; |
762 | case Opt_keyauth: |
763 | if (strlen(args[0].from) != 2 * SHA1_DIGEST_SIZE) |
764 | return -EINVAL; |
765 | res = hex2bin(opt->keyauth, args[0].from, |
766 | SHA1_DIGEST_SIZE); |
767 | if (res < 0) |
768 | return -EINVAL; |
769 | break; |
770 | case Opt_blobauth: |
771 | if (strlen(args[0].from) != 2 * SHA1_DIGEST_SIZE) |
772 | return -EINVAL; |
773 | res = hex2bin(opt->blobauth, args[0].from, |
774 | SHA1_DIGEST_SIZE); |
775 | if (res < 0) |
776 | return -EINVAL; |
777 | break; |
778 | case Opt_migratable: |
779 | if (*args[0].from == '0') |
780 | pay->migratable = 0; |
781 | else |
782 | return -EINVAL; |
783 | break; |
784 | case Opt_pcrlock: |
785 | res = strict_strtoul(args[0].from, 10, &lock); |
786 | if (res < 0) |
787 | return -EINVAL; |
788 | opt->pcrlock = lock; |
789 | break; |
790 | default: |
791 | return -EINVAL; |
792 | } |
793 | } |
794 | return 0; |
795 | } |
796 | |
797 | /* |
798 | * datablob_parse - parse the keyctl data and fill in the |
799 | * payload and options structures |
800 | * |
801 | * On success returns 0, otherwise -EINVAL. |
802 | */ |
803 | static int datablob_parse(char *datablob, struct trusted_key_payload *p, |
804 | struct trusted_key_options *o) |
805 | { |
806 | substring_t args[MAX_OPT_ARGS]; |
807 | long keylen; |
808 | int ret = -EINVAL; |
809 | int key_cmd; |
810 | char *c; |
811 | |
812 | /* main command */ |
813 | c = strsep(&datablob, " \t"); |
814 | if (!c) |
815 | return -EINVAL; |
816 | key_cmd = match_token(c, key_tokens, args); |
817 | switch (key_cmd) { |
818 | case Opt_new: |
819 | /* first argument is key size */ |
820 | c = strsep(&datablob, " \t"); |
821 | if (!c) |
822 | return -EINVAL; |
823 | ret = strict_strtol(c, 10, &keylen); |
824 | if (ret < 0 || keylen < MIN_KEY_SIZE || keylen > MAX_KEY_SIZE) |
825 | return -EINVAL; |
826 | p->key_len = keylen; |
827 | ret = getoptions(datablob, p, o); |
828 | if (ret < 0) |
829 | return ret; |
830 | ret = Opt_new; |
831 | break; |
832 | case Opt_load: |
833 | /* first argument is sealed blob */ |
834 | c = strsep(&datablob, " \t"); |
835 | if (!c) |
836 | return -EINVAL; |
837 | p->blob_len = strlen(c) / 2; |
838 | if (p->blob_len > MAX_BLOB_SIZE) |
839 | return -EINVAL; |
840 | ret = hex2bin(p->blob, c, p->blob_len); |
841 | if (ret < 0) |
842 | return -EINVAL; |
843 | ret = getoptions(datablob, p, o); |
844 | if (ret < 0) |
845 | return ret; |
846 | ret = Opt_load; |
847 | break; |
848 | case Opt_update: |
849 | /* all arguments are options */ |
850 | ret = getoptions(datablob, p, o); |
851 | if (ret < 0) |
852 | return ret; |
853 | ret = Opt_update; |
854 | break; |
855 | case Opt_err: |
856 | return -EINVAL; |
857 | break; |
858 | } |
859 | return ret; |
860 | } |
861 | |
862 | static struct trusted_key_options *trusted_options_alloc(void) |
863 | { |
864 | struct trusted_key_options *options; |
865 | |
866 | options = kzalloc(sizeof *options, GFP_KERNEL); |
867 | if (options) { |
868 | /* set any non-zero defaults */ |
869 | options->keytype = SRK_keytype; |
870 | options->keyhandle = SRKHANDLE; |
871 | } |
872 | return options; |
873 | } |
874 | |
875 | static struct trusted_key_payload *trusted_payload_alloc(struct key *key) |
876 | { |
877 | struct trusted_key_payload *p = NULL; |
878 | int ret; |
879 | |
880 | ret = key_payload_reserve(key, sizeof *p); |
881 | if (ret < 0) |
882 | return p; |
883 | p = kzalloc(sizeof *p, GFP_KERNEL); |
884 | if (p) |
885 | p->migratable = 1; /* migratable by default */ |
886 | return p; |
887 | } |
888 | |
889 | /* |
890 | * trusted_instantiate - create a new trusted key |
891 | * |
892 | * Unseal an existing trusted blob or, for a new key, get a |
893 | * random key, then seal and create a trusted key-type key, |
894 | * adding it to the specified keyring. |
895 | * |
896 | * On success, return 0. Otherwise return errno. |
897 | */ |
898 | static int trusted_instantiate(struct key *key, |
899 | struct key_preparsed_payload *prep) |
900 | { |
901 | struct trusted_key_payload *payload = NULL; |
902 | struct trusted_key_options *options = NULL; |
903 | size_t datalen = prep->datalen; |
904 | char *datablob; |
905 | int ret = 0; |
906 | int key_cmd; |
907 | size_t key_len; |
908 | |
909 | if (datalen <= 0 || datalen > 32767 || !prep->data) |
910 | return -EINVAL; |
911 | |
912 | datablob = kmalloc(datalen + 1, GFP_KERNEL); |
913 | if (!datablob) |
914 | return -ENOMEM; |
915 | memcpy(datablob, prep->data, datalen); |
916 | datablob[datalen] = '\0'; |
917 | |
918 | options = trusted_options_alloc(); |
919 | if (!options) { |
920 | ret = -ENOMEM; |
921 | goto out; |
922 | } |
923 | payload = trusted_payload_alloc(key); |
924 | if (!payload) { |
925 | ret = -ENOMEM; |
926 | goto out; |
927 | } |
928 | |
929 | key_cmd = datablob_parse(datablob, payload, options); |
930 | if (key_cmd < 0) { |
931 | ret = key_cmd; |
932 | goto out; |
933 | } |
934 | |
935 | dump_payload(payload); |
936 | dump_options(options); |
937 | |
938 | switch (key_cmd) { |
939 | case Opt_load: |
940 | ret = key_unseal(payload, options); |
941 | dump_payload(payload); |
942 | dump_options(options); |
943 | if (ret < 0) |
944 | pr_info("trusted_key: key_unseal failed (%d)\n", ret); |
945 | break; |
946 | case Opt_new: |
947 | key_len = payload->key_len; |
948 | ret = tpm_get_random(TPM_ANY_NUM, payload->key, key_len); |
949 | if (ret != key_len) { |
950 | pr_info("trusted_key: key_create failed (%d)\n", ret); |
951 | goto out; |
952 | } |
953 | ret = key_seal(payload, options); |
954 | if (ret < 0) |
955 | pr_info("trusted_key: key_seal failed (%d)\n", ret); |
956 | break; |
957 | default: |
958 | ret = -EINVAL; |
959 | goto out; |
960 | } |
961 | if (!ret && options->pcrlock) |
962 | ret = pcrlock(options->pcrlock); |
963 | out: |
964 | kfree(datablob); |
965 | kfree(options); |
966 | if (!ret) |
967 | rcu_assign_keypointer(key, payload); |
968 | else |
969 | kfree(payload); |
970 | return ret; |
971 | } |
972 | |
973 | static void trusted_rcu_free(struct rcu_head *rcu) |
974 | { |
975 | struct trusted_key_payload *p; |
976 | |
977 | p = container_of(rcu, struct trusted_key_payload, rcu); |
978 | memset(p->key, 0, p->key_len); |
979 | kfree(p); |
980 | } |
981 | |
982 | /* |
983 | * trusted_update - reseal an existing key with new PCR values |
984 | */ |
985 | static int trusted_update(struct key *key, struct key_preparsed_payload *prep) |
986 | { |
987 | struct trusted_key_payload *p = key->payload.data; |
988 | struct trusted_key_payload *new_p; |
989 | struct trusted_key_options *new_o; |
990 | size_t datalen = prep->datalen; |
991 | char *datablob; |
992 | int ret = 0; |
993 | |
994 | if (!p->migratable) |
995 | return -EPERM; |
996 | if (datalen <= 0 || datalen > 32767 || !prep->data) |
997 | return -EINVAL; |
998 | |
999 | datablob = kmalloc(datalen + 1, GFP_KERNEL); |
1000 | if (!datablob) |
1001 | return -ENOMEM; |
1002 | new_o = trusted_options_alloc(); |
1003 | if (!new_o) { |
1004 | ret = -ENOMEM; |
1005 | goto out; |
1006 | } |
1007 | new_p = trusted_payload_alloc(key); |
1008 | if (!new_p) { |
1009 | ret = -ENOMEM; |
1010 | goto out; |
1011 | } |
1012 | |
1013 | memcpy(datablob, prep->data, datalen); |
1014 | datablob[datalen] = '\0'; |
1015 | ret = datablob_parse(datablob, new_p, new_o); |
1016 | if (ret != Opt_update) { |
1017 | ret = -EINVAL; |
1018 | kfree(new_p); |
1019 | goto out; |
1020 | } |
1021 | /* copy old key values, and reseal with new pcrs */ |
1022 | new_p->migratable = p->migratable; |
1023 | new_p->key_len = p->key_len; |
1024 | memcpy(new_p->key, p->key, p->key_len); |
1025 | dump_payload(p); |
1026 | dump_payload(new_p); |
1027 | |
1028 | ret = key_seal(new_p, new_o); |
1029 | if (ret < 0) { |
1030 | pr_info("trusted_key: key_seal failed (%d)\n", ret); |
1031 | kfree(new_p); |
1032 | goto out; |
1033 | } |
1034 | if (new_o->pcrlock) { |
1035 | ret = pcrlock(new_o->pcrlock); |
1036 | if (ret < 0) { |
1037 | pr_info("trusted_key: pcrlock failed (%d)\n", ret); |
1038 | kfree(new_p); |
1039 | goto out; |
1040 | } |
1041 | } |
1042 | rcu_assign_keypointer(key, new_p); |
1043 | call_rcu(&p->rcu, trusted_rcu_free); |
1044 | out: |
1045 | kfree(datablob); |
1046 | kfree(new_o); |
1047 | return ret; |
1048 | } |
1049 | |
1050 | /* |
1051 | * trusted_read - copy the sealed blob data to userspace in hex. |
1052 | * On success, return to userspace the trusted key datablob size. |
1053 | */ |
1054 | static long trusted_read(const struct key *key, char __user *buffer, |
1055 | size_t buflen) |
1056 | { |
1057 | struct trusted_key_payload *p; |
1058 | char *ascii_buf; |
1059 | char *bufp; |
1060 | int i; |
1061 | |
1062 | p = rcu_dereference_key(key); |
1063 | if (!p) |
1064 | return -EINVAL; |
1065 | if (!buffer || buflen <= 0) |
1066 | return 2 * p->blob_len; |
1067 | ascii_buf = kmalloc(2 * p->blob_len, GFP_KERNEL); |
1068 | if (!ascii_buf) |
1069 | return -ENOMEM; |
1070 | |
1071 | bufp = ascii_buf; |
1072 | for (i = 0; i < p->blob_len; i++) |
1073 | bufp = hex_byte_pack(bufp, p->blob[i]); |
1074 | if ((copy_to_user(buffer, ascii_buf, 2 * p->blob_len)) != 0) { |
1075 | kfree(ascii_buf); |
1076 | return -EFAULT; |
1077 | } |
1078 | kfree(ascii_buf); |
1079 | return 2 * p->blob_len; |
1080 | } |
1081 | |
1082 | /* |
1083 | * trusted_destroy - before freeing the key, clear the decrypted data |
1084 | */ |
1085 | static void trusted_destroy(struct key *key) |
1086 | { |
1087 | struct trusted_key_payload *p = key->payload.data; |
1088 | |
1089 | if (!p) |
1090 | return; |
1091 | memset(p->key, 0, p->key_len); |
1092 | kfree(key->payload.data); |
1093 | } |
1094 | |
1095 | struct key_type key_type_trusted = { |
1096 | .name = "trusted", |
1097 | .instantiate = trusted_instantiate, |
1098 | .update = trusted_update, |
1099 | .match = user_match, |
1100 | .destroy = trusted_destroy, |
1101 | .describe = user_describe, |
1102 | .read = trusted_read, |
1103 | }; |
1104 | |
1105 | EXPORT_SYMBOL_GPL(key_type_trusted); |
1106 | |
1107 | static void trusted_shash_release(void) |
1108 | { |
1109 | if (hashalg) |
1110 | crypto_free_shash(hashalg); |
1111 | if (hmacalg) |
1112 | crypto_free_shash(hmacalg); |
1113 | } |
1114 | |
1115 | static int __init trusted_shash_alloc(void) |
1116 | { |
1117 | int ret; |
1118 | |
1119 | hmacalg = crypto_alloc_shash(hmac_alg, 0, CRYPTO_ALG_ASYNC); |
1120 | if (IS_ERR(hmacalg)) { |
1121 | pr_info("trusted_key: could not allocate crypto %s\n", |
1122 | hmac_alg); |
1123 | return PTR_ERR(hmacalg); |
1124 | } |
1125 | |
1126 | hashalg = crypto_alloc_shash(hash_alg, 0, CRYPTO_ALG_ASYNC); |
1127 | if (IS_ERR(hashalg)) { |
1128 | pr_info("trusted_key: could not allocate crypto %s\n", |
1129 | hash_alg); |
1130 | ret = PTR_ERR(hashalg); |
1131 | goto hashalg_fail; |
1132 | } |
1133 | |
1134 | return 0; |
1135 | |
1136 | hashalg_fail: |
1137 | crypto_free_shash(hmacalg); |
1138 | return ret; |
1139 | } |
1140 | |
1141 | static int __init init_trusted(void) |
1142 | { |
1143 | int ret; |
1144 | |
1145 | ret = trusted_shash_alloc(); |
1146 | if (ret < 0) |
1147 | return ret; |
1148 | ret = register_key_type(&key_type_trusted); |
1149 | if (ret < 0) |
1150 | trusted_shash_release(); |
1151 | return ret; |
1152 | } |
1153 | |
1154 | static void __exit cleanup_trusted(void) |
1155 | { |
1156 | trusted_shash_release(); |
1157 | unregister_key_type(&key_type_trusted); |
1158 | } |
1159 | |
1160 | late_initcall(init_trusted); |
1161 | module_exit(cleanup_trusted); |
1162 | |
1163 | MODULE_LICENSE("GPL"); |
1164 |
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