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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
34static const char hmac_alg[] = "hmac(sha1)";
35static const char hash_alg[] = "sha1";
36
37struct sdesc {
38 struct shash_desc shash;
39 char ctx[];
40};
41
42static struct crypto_shash *hashalg;
43static struct crypto_shash *hmacalg;
44
45static 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
59static 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
76static 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);
115out:
116 kfree(sdesc);
117 return ret;
118}
119
120/*
121 * calculate authorization info fields to send to TPM
122 */
123static 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);
166out:
167 kfree(sdesc);
168 return ret;
169}
170
171/*
172 * verify the AUTH1_COMMAND (Seal) result from TPM
173 */
174static 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;
247out:
248 kfree(sdesc);
249 return ret;
250}
251
252/*
253 * verify the AUTH2_COMMAND (unseal) result from TPM
254 */
255static 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;
348out:
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 */
357static 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 * get a random value from TPM
373 */
374static int tpm_get_random(struct tpm_buf *tb, unsigned char *buf, uint32_t len)
375{
376 int ret;
377
378 INIT_BUF(tb);
379 store16(tb, TPM_TAG_RQU_COMMAND);
380 store32(tb, TPM_GETRANDOM_SIZE);
381 store32(tb, TPM_ORD_GETRANDOM);
382 store32(tb, len);
383 ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, sizeof tb->data);
384 if (!ret)
385 memcpy(buf, tb->data + TPM_GETRANDOM_SIZE, len);
386 return ret;
387}
388
389static int my_get_random(unsigned char *buf, int len)
390{
391 struct tpm_buf *tb;
392 int ret;
393
394 tb = kmalloc(sizeof *tb, GFP_KERNEL);
395 if (!tb)
396 return -ENOMEM;
397 ret = tpm_get_random(tb, buf, len);
398
399 kfree(tb);
400 return ret;
401}
402
403/*
404 * Lock a trusted key, by extending a selected PCR.
405 *
406 * Prevents a trusted key that is sealed to PCRs from being accessed.
407 * This uses the tpm driver's extend function.
408 */
409static int pcrlock(const int pcrnum)
410{
411 unsigned char hash[SHA1_DIGEST_SIZE];
412 int ret;
413
414 if (!capable(CAP_SYS_ADMIN))
415 return -EPERM;
416 ret = my_get_random(hash, SHA1_DIGEST_SIZE);
417 if (ret < 0)
418 return ret;
419 return tpm_pcr_extend(TPM_ANY_NUM, pcrnum, hash) ? -EINVAL : 0;
420}
421
422/*
423 * Create an object specific authorisation protocol (OSAP) session
424 */
425static int osap(struct tpm_buf *tb, struct osapsess *s,
426 const unsigned char *key, uint16_t type, uint32_t handle)
427{
428 unsigned char enonce[TPM_NONCE_SIZE];
429 unsigned char ononce[TPM_NONCE_SIZE];
430 int ret;
431
432 ret = tpm_get_random(tb, ononce, TPM_NONCE_SIZE);
433 if (ret < 0)
434 return ret;
435
436 INIT_BUF(tb);
437 store16(tb, TPM_TAG_RQU_COMMAND);
438 store32(tb, TPM_OSAP_SIZE);
439 store32(tb, TPM_ORD_OSAP);
440 store16(tb, type);
441 store32(tb, handle);
442 storebytes(tb, ononce, TPM_NONCE_SIZE);
443
444 ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE);
445 if (ret < 0)
446 return ret;
447
448 s->handle = LOAD32(tb->data, TPM_DATA_OFFSET);
449 memcpy(s->enonce, &(tb->data[TPM_DATA_OFFSET + sizeof(uint32_t)]),
450 TPM_NONCE_SIZE);
451 memcpy(enonce, &(tb->data[TPM_DATA_OFFSET + sizeof(uint32_t) +
452 TPM_NONCE_SIZE]), TPM_NONCE_SIZE);
453 return TSS_rawhmac(s->secret, key, SHA1_DIGEST_SIZE, TPM_NONCE_SIZE,
454 enonce, TPM_NONCE_SIZE, ononce, 0, 0);
455}
456
457/*
458 * Create an object independent authorisation protocol (oiap) session
459 */
460static int oiap(struct tpm_buf *tb, uint32_t *handle, unsigned char *nonce)
461{
462 int ret;
463
464 INIT_BUF(tb);
465 store16(tb, TPM_TAG_RQU_COMMAND);
466 store32(tb, TPM_OIAP_SIZE);
467 store32(tb, TPM_ORD_OIAP);
468 ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE);
469 if (ret < 0)
470 return ret;
471
472 *handle = LOAD32(tb->data, TPM_DATA_OFFSET);
473 memcpy(nonce, &tb->data[TPM_DATA_OFFSET + sizeof(uint32_t)],
474 TPM_NONCE_SIZE);
475 return 0;
476}
477
478struct tpm_digests {
479 unsigned char encauth[SHA1_DIGEST_SIZE];
480 unsigned char pubauth[SHA1_DIGEST_SIZE];
481 unsigned char xorwork[SHA1_DIGEST_SIZE * 2];
482 unsigned char xorhash[SHA1_DIGEST_SIZE];
483 unsigned char nonceodd[TPM_NONCE_SIZE];
484};
485
486/*
487 * Have the TPM seal(encrypt) the trusted key, possibly based on
488 * Platform Configuration Registers (PCRs). AUTH1 for sealing key.
489 */
490static int tpm_seal(struct tpm_buf *tb, uint16_t keytype,
491 uint32_t keyhandle, const unsigned char *keyauth,
492 const unsigned char *data, uint32_t datalen,
493 unsigned char *blob, uint32_t *bloblen,
494 const unsigned char *blobauth,
495 const unsigned char *pcrinfo, uint32_t pcrinfosize)
496{
497 struct osapsess sess;
498 struct tpm_digests *td;
499 unsigned char cont;
500 uint32_t ordinal;
501 uint32_t pcrsize;
502 uint32_t datsize;
503 int sealinfosize;
504 int encdatasize;
505 int storedsize;
506 int ret;
507 int i;
508
509 /* alloc some work space for all the hashes */
510 td = kmalloc(sizeof *td, GFP_KERNEL);
511 if (!td)
512 return -ENOMEM;
513
514 /* get session for sealing key */
515 ret = osap(tb, &sess, keyauth, keytype, keyhandle);
516 if (ret < 0)
517 goto out;
518 dump_sess(&sess);
519
520 /* calculate encrypted authorization value */
521 memcpy(td->xorwork, sess.secret, SHA1_DIGEST_SIZE);
522 memcpy(td->xorwork + SHA1_DIGEST_SIZE, sess.enonce, SHA1_DIGEST_SIZE);
523 ret = TSS_sha1(td->xorwork, SHA1_DIGEST_SIZE * 2, td->xorhash);
524 if (ret < 0)
525 goto out;
526
527 ret = tpm_get_random(tb, td->nonceodd, TPM_NONCE_SIZE);
528 if (ret < 0)
529 goto out;
530 ordinal = htonl(TPM_ORD_SEAL);
531 datsize = htonl(datalen);
532 pcrsize = htonl(pcrinfosize);
533 cont = 0;
534
535 /* encrypt data authorization key */
536 for (i = 0; i < SHA1_DIGEST_SIZE; ++i)
537 td->encauth[i] = td->xorhash[i] ^ blobauth[i];
538
539 /* calculate authorization HMAC value */
540 if (pcrinfosize == 0) {
541 /* no pcr info specified */
542 ret = TSS_authhmac(td->pubauth, sess.secret, SHA1_DIGEST_SIZE,
543 sess.enonce, td->nonceodd, cont,
544 sizeof(uint32_t), &ordinal, SHA1_DIGEST_SIZE,
545 td->encauth, sizeof(uint32_t), &pcrsize,
546 sizeof(uint32_t), &datsize, datalen, data, 0,
547 0);
548 } else {
549 /* pcr info specified */
550 ret = TSS_authhmac(td->pubauth, sess.secret, SHA1_DIGEST_SIZE,
551 sess.enonce, td->nonceodd, cont,
552 sizeof(uint32_t), &ordinal, SHA1_DIGEST_SIZE,
553 td->encauth, sizeof(uint32_t), &pcrsize,
554 pcrinfosize, pcrinfo, sizeof(uint32_t),
555 &datsize, datalen, data, 0, 0);
556 }
557 if (ret < 0)
558 goto out;
559
560 /* build and send the TPM request packet */
561 INIT_BUF(tb);
562 store16(tb, TPM_TAG_RQU_AUTH1_COMMAND);
563 store32(tb, TPM_SEAL_SIZE + pcrinfosize + datalen);
564 store32(tb, TPM_ORD_SEAL);
565 store32(tb, keyhandle);
566 storebytes(tb, td->encauth, SHA1_DIGEST_SIZE);
567 store32(tb, pcrinfosize);
568 storebytes(tb, pcrinfo, pcrinfosize);
569 store32(tb, datalen);
570 storebytes(tb, data, datalen);
571 store32(tb, sess.handle);
572 storebytes(tb, td->nonceodd, TPM_NONCE_SIZE);
573 store8(tb, cont);
574 storebytes(tb, td->pubauth, SHA1_DIGEST_SIZE);
575
576 ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE);
577 if (ret < 0)
578 goto out;
579
580 /* calculate the size of the returned Blob */
581 sealinfosize = LOAD32(tb->data, TPM_DATA_OFFSET + sizeof(uint32_t));
582 encdatasize = LOAD32(tb->data, TPM_DATA_OFFSET + sizeof(uint32_t) +
583 sizeof(uint32_t) + sealinfosize);
584 storedsize = sizeof(uint32_t) + sizeof(uint32_t) + sealinfosize +
585 sizeof(uint32_t) + encdatasize;
586
587 /* check the HMAC in the response */
588 ret = TSS_checkhmac1(tb->data, ordinal, td->nonceodd, sess.secret,
589 SHA1_DIGEST_SIZE, storedsize, TPM_DATA_OFFSET, 0,
590 0);
591
592 /* copy the returned blob to caller */
593 if (!ret) {
594 memcpy(blob, tb->data + TPM_DATA_OFFSET, storedsize);
595 *bloblen = storedsize;
596 }
597out:
598 kfree(td);
599 return ret;
600}
601
602/*
603 * use the AUTH2_COMMAND form of unseal, to authorize both key and blob
604 */
605static int tpm_unseal(struct tpm_buf *tb,
606 uint32_t keyhandle, const unsigned char *keyauth,
607 const unsigned char *blob, int bloblen,
608 const unsigned char *blobauth,
609 unsigned char *data, unsigned int *datalen)
610{
611 unsigned char nonceodd[TPM_NONCE_SIZE];
612 unsigned char enonce1[TPM_NONCE_SIZE];
613 unsigned char enonce2[TPM_NONCE_SIZE];
614 unsigned char authdata1[SHA1_DIGEST_SIZE];
615 unsigned char authdata2[SHA1_DIGEST_SIZE];
616 uint32_t authhandle1 = 0;
617 uint32_t authhandle2 = 0;
618 unsigned char cont = 0;
619 uint32_t ordinal;
620 uint32_t keyhndl;
621 int ret;
622
623 /* sessions for unsealing key and data */
624 ret = oiap(tb, &authhandle1, enonce1);
625 if (ret < 0) {
626 pr_info("trusted_key: oiap failed (%d)\n", ret);
627 return ret;
628 }
629 ret = oiap(tb, &authhandle2, enonce2);
630 if (ret < 0) {
631 pr_info("trusted_key: oiap failed (%d)\n", ret);
632 return ret;
633 }
634
635 ordinal = htonl(TPM_ORD_UNSEAL);
636 keyhndl = htonl(SRKHANDLE);
637 ret = tpm_get_random(tb, nonceodd, TPM_NONCE_SIZE);
638 if (ret < 0) {
639 pr_info("trusted_key: tpm_get_random failed (%d)\n", ret);
640 return ret;
641 }
642 ret = TSS_authhmac(authdata1, keyauth, TPM_NONCE_SIZE,
643 enonce1, nonceodd, cont, sizeof(uint32_t),
644 &ordinal, bloblen, blob, 0, 0);
645 if (ret < 0)
646 return ret;
647 ret = TSS_authhmac(authdata2, blobauth, TPM_NONCE_SIZE,
648 enonce2, nonceodd, cont, sizeof(uint32_t),
649 &ordinal, bloblen, blob, 0, 0);
650 if (ret < 0)
651 return ret;
652
653 /* build and send TPM request packet */
654 INIT_BUF(tb);
655 store16(tb, TPM_TAG_RQU_AUTH2_COMMAND);
656 store32(tb, TPM_UNSEAL_SIZE + bloblen);
657 store32(tb, TPM_ORD_UNSEAL);
658 store32(tb, keyhandle);
659 storebytes(tb, blob, bloblen);
660 store32(tb, authhandle1);
661 storebytes(tb, nonceodd, TPM_NONCE_SIZE);
662 store8(tb, cont);
663 storebytes(tb, authdata1, SHA1_DIGEST_SIZE);
664 store32(tb, authhandle2);
665 storebytes(tb, nonceodd, TPM_NONCE_SIZE);
666 store8(tb, cont);
667 storebytes(tb, authdata2, SHA1_DIGEST_SIZE);
668
669 ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE);
670 if (ret < 0) {
671 pr_info("trusted_key: authhmac failed (%d)\n", ret);
672 return ret;
673 }
674
675 *datalen = LOAD32(tb->data, TPM_DATA_OFFSET);
676 ret = TSS_checkhmac2(tb->data, ordinal, nonceodd,
677 keyauth, SHA1_DIGEST_SIZE,
678 blobauth, SHA1_DIGEST_SIZE,
679 sizeof(uint32_t), TPM_DATA_OFFSET,
680 *datalen, TPM_DATA_OFFSET + sizeof(uint32_t), 0,
681 0);
682 if (ret < 0) {
683 pr_info("trusted_key: TSS_checkhmac2 failed (%d)\n", ret);
684 return ret;
685 }
686 memcpy(data, tb->data + TPM_DATA_OFFSET + sizeof(uint32_t), *datalen);
687 return 0;
688}
689
690/*
691 * Have the TPM seal(encrypt) the symmetric key
692 */
693static int key_seal(struct trusted_key_payload *p,
694 struct trusted_key_options *o)
695{
696 struct tpm_buf *tb;
697 int ret;
698
699 tb = kzalloc(sizeof *tb, GFP_KERNEL);
700 if (!tb)
701 return -ENOMEM;
702
703 /* include migratable flag at end of sealed key */
704 p->key[p->key_len] = p->migratable;
705
706 ret = tpm_seal(tb, o->keytype, o->keyhandle, o->keyauth,
707 p->key, p->key_len + 1, p->blob, &p->blob_len,
708 o->blobauth, o->pcrinfo, o->pcrinfo_len);
709 if (ret < 0)
710 pr_info("trusted_key: srkseal failed (%d)\n", ret);
711
712 kfree(tb);
713 return ret;
714}
715
716/*
717 * Have the TPM unseal(decrypt) the symmetric key
718 */
719static int key_unseal(struct trusted_key_payload *p,
720 struct trusted_key_options *o)
721{
722 struct tpm_buf *tb;
723 int ret;
724
725 tb = kzalloc(sizeof *tb, GFP_KERNEL);
726 if (!tb)
727 return -ENOMEM;
728
729 ret = tpm_unseal(tb, o->keyhandle, o->keyauth, p->blob, p->blob_len,
730 o->blobauth, p->key, &p->key_len);
731 if (ret < 0)
732 pr_info("trusted_key: srkunseal failed (%d)\n", ret);
733 else
734 /* pull migratable flag out of sealed key */
735 p->migratable = p->key[--p->key_len];
736
737 kfree(tb);
738 return ret;
739}
740
741enum {
742 Opt_err = -1,
743 Opt_new, Opt_load, Opt_update,
744 Opt_keyhandle, Opt_keyauth, Opt_blobauth,
745 Opt_pcrinfo, Opt_pcrlock, Opt_migratable
746};
747
748static const match_table_t key_tokens = {
749 {Opt_new, "new"},
750 {Opt_load, "load"},
751 {Opt_update, "update"},
752 {Opt_keyhandle, "keyhandle=%s"},
753 {Opt_keyauth, "keyauth=%s"},
754 {Opt_blobauth, "blobauth=%s"},
755 {Opt_pcrinfo, "pcrinfo=%s"},
756 {Opt_pcrlock, "pcrlock=%s"},
757 {Opt_migratable, "migratable=%s"},
758 {Opt_err, NULL}
759};
760
761/* can have zero or more token= options */
762static int getoptions(char *c, struct trusted_key_payload *pay,
763 struct trusted_key_options *opt)
764{
765 substring_t args[MAX_OPT_ARGS];
766 char *p = c;
767 int token;
768 int res;
769 unsigned long handle;
770 unsigned long lock;
771
772 while ((p = strsep(&c, " \t"))) {
773 if (*p == '\0' || *p == ' ' || *p == '\t')
774 continue;
775 token = match_token(p, key_tokens, args);
776
777 switch (token) {
778 case Opt_pcrinfo:
779 opt->pcrinfo_len = strlen(args[0].from) / 2;
780 if (opt->pcrinfo_len > MAX_PCRINFO_SIZE)
781 return -EINVAL;
782 hex2bin(opt->pcrinfo, args[0].from, opt->pcrinfo_len);
783 break;
784 case Opt_keyhandle:
785 res = strict_strtoul(args[0].from, 16, &handle);
786 if (res < 0)
787 return -EINVAL;
788 opt->keytype = SEAL_keytype;
789 opt->keyhandle = handle;
790 break;
791 case Opt_keyauth:
792 if (strlen(args[0].from) != 2 * SHA1_DIGEST_SIZE)
793 return -EINVAL;
794 hex2bin(opt->keyauth, args[0].from, SHA1_DIGEST_SIZE);
795 break;
796 case Opt_blobauth:
797 if (strlen(args[0].from) != 2 * SHA1_DIGEST_SIZE)
798 return -EINVAL;
799 hex2bin(opt->blobauth, args[0].from, SHA1_DIGEST_SIZE);
800 break;
801 case Opt_migratable:
802 if (*args[0].from == '0')
803 pay->migratable = 0;
804 else
805 return -EINVAL;
806 break;
807 case Opt_pcrlock:
808 res = strict_strtoul(args[0].from, 10, &lock);
809 if (res < 0)
810 return -EINVAL;
811 opt->pcrlock = lock;
812 break;
813 default:
814 return -EINVAL;
815 }
816 }
817 return 0;
818}
819
820/*
821 * datablob_parse - parse the keyctl data and fill in the
822 * payload and options structures
823 *
824 * On success returns 0, otherwise -EINVAL.
825 */
826static int datablob_parse(char *datablob, struct trusted_key_payload *p,
827 struct trusted_key_options *o)
828{
829 substring_t args[MAX_OPT_ARGS];
830 long keylen;
831 int ret = -EINVAL;
832 int key_cmd;
833 char *c;
834
835 /* main command */
836 c = strsep(&datablob, " \t");
837 if (!c)
838 return -EINVAL;
839 key_cmd = match_token(c, key_tokens, args);
840 switch (key_cmd) {
841 case Opt_new:
842 /* first argument is key size */
843 c = strsep(&datablob, " \t");
844 if (!c)
845 return -EINVAL;
846 ret = strict_strtol(c, 10, &keylen);
847 if (ret < 0 || keylen < MIN_KEY_SIZE || keylen > MAX_KEY_SIZE)
848 return -EINVAL;
849 p->key_len = keylen;
850 ret = getoptions(datablob, p, o);
851 if (ret < 0)
852 return ret;
853 ret = Opt_new;
854 break;
855 case Opt_load:
856 /* first argument is sealed blob */
857 c = strsep(&datablob, " \t");
858 if (!c)
859 return -EINVAL;
860 p->blob_len = strlen(c) / 2;
861 if (p->blob_len > MAX_BLOB_SIZE)
862 return -EINVAL;
863 hex2bin(p->blob, c, p->blob_len);
864 ret = getoptions(datablob, p, o);
865 if (ret < 0)
866 return ret;
867 ret = Opt_load;
868 break;
869 case Opt_update:
870 /* all arguments are options */
871 ret = getoptions(datablob, p, o);
872 if (ret < 0)
873 return ret;
874 ret = Opt_update;
875 break;
876 case Opt_err:
877 return -EINVAL;
878 break;
879 }
880 return ret;
881}
882
883static struct trusted_key_options *trusted_options_alloc(void)
884{
885 struct trusted_key_options *options;
886
887 options = kzalloc(sizeof *options, GFP_KERNEL);
888 if (options) {
889 /* set any non-zero defaults */
890 options->keytype = SRK_keytype;
891 options->keyhandle = SRKHANDLE;
892 }
893 return options;
894}
895
896static struct trusted_key_payload *trusted_payload_alloc(struct key *key)
897{
898 struct trusted_key_payload *p = NULL;
899 int ret;
900
901 ret = key_payload_reserve(key, sizeof *p);
902 if (ret < 0)
903 return p;
904 p = kzalloc(sizeof *p, GFP_KERNEL);
905 if (p)
906 p->migratable = 1; /* migratable by default */
907 return p;
908}
909
910/*
911 * trusted_instantiate - create a new trusted key
912 *
913 * Unseal an existing trusted blob or, for a new key, get a
914 * random key, then seal and create a trusted key-type key,
915 * adding it to the specified keyring.
916 *
917 * On success, return 0. Otherwise return errno.
918 */
919static int trusted_instantiate(struct key *key, const void *data,
920 size_t datalen)
921{
922 struct trusted_key_payload *payload = NULL;
923 struct trusted_key_options *options = NULL;
924 char *datablob;
925 int ret = 0;
926 int key_cmd;
927
928 if (datalen <= 0 || datalen > 32767 || !data)
929 return -EINVAL;
930
931 datablob = kmalloc(datalen + 1, GFP_KERNEL);
932 if (!datablob)
933 return -ENOMEM;
934 memcpy(datablob, data, datalen);
935 datablob[datalen] = '\0';
936
937 options = trusted_options_alloc();
938 if (!options) {
939 ret = -ENOMEM;
940 goto out;
941 }
942 payload = trusted_payload_alloc(key);
943 if (!payload) {
944 ret = -ENOMEM;
945 goto out;
946 }
947
948 key_cmd = datablob_parse(datablob, payload, options);
949 if (key_cmd < 0) {
950 ret = key_cmd;
951 goto out;
952 }
953
954 dump_payload(payload);
955 dump_options(options);
956
957 switch (key_cmd) {
958 case Opt_load:
959 ret = key_unseal(payload, options);
960 dump_payload(payload);
961 dump_options(options);
962 if (ret < 0)
963 pr_info("trusted_key: key_unseal failed (%d)\n", ret);
964 break;
965 case Opt_new:
966 ret = my_get_random(payload->key, payload->key_len);
967 if (ret < 0) {
968 pr_info("trusted_key: key_create failed (%d)\n", ret);
969 goto out;
970 }
971 ret = key_seal(payload, options);
972 if (ret < 0)
973 pr_info("trusted_key: key_seal failed (%d)\n", ret);
974 break;
975 default:
976 ret = -EINVAL;
977 goto out;
978 }
979 if (!ret && options->pcrlock)
980 ret = pcrlock(options->pcrlock);
981out:
982 kfree(datablob);
983 kfree(options);
984 if (!ret)
985 rcu_assign_pointer(key->payload.data, payload);
986 else
987 kfree(payload);
988 return ret;
989}
990
991static void trusted_rcu_free(struct rcu_head *rcu)
992{
993 struct trusted_key_payload *p;
994
995 p = container_of(rcu, struct trusted_key_payload, rcu);
996 memset(p->key, 0, p->key_len);
997 kfree(p);
998}
999
1000/*
1001 * trusted_update - reseal an existing key with new PCR values
1002 */
1003static int trusted_update(struct key *key, const void *data, size_t datalen)
1004{
1005 struct trusted_key_payload *p = key->payload.data;
1006 struct trusted_key_payload *new_p;
1007 struct trusted_key_options *new_o;
1008 char *datablob;
1009 int ret = 0;
1010
1011 if (!p->migratable)
1012 return -EPERM;
1013 if (datalen <= 0 || datalen > 32767 || !data)
1014 return -EINVAL;
1015
1016 datablob = kmalloc(datalen + 1, GFP_KERNEL);
1017 if (!datablob)
1018 return -ENOMEM;
1019 new_o = trusted_options_alloc();
1020 if (!new_o) {
1021 ret = -ENOMEM;
1022 goto out;
1023 }
1024 new_p = trusted_payload_alloc(key);
1025 if (!new_p) {
1026 ret = -ENOMEM;
1027 goto out;
1028 }
1029
1030 memcpy(datablob, data, datalen);
1031 datablob[datalen] = '\0';
1032 ret = datablob_parse(datablob, new_p, new_o);
1033 if (ret != Opt_update) {
1034 ret = -EINVAL;
1035 kfree(new_p);
1036 goto out;
1037 }
1038 /* copy old key values, and reseal with new pcrs */
1039 new_p->migratable = p->migratable;
1040 new_p->key_len = p->key_len;
1041 memcpy(new_p->key, p->key, p->key_len);
1042 dump_payload(p);
1043 dump_payload(new_p);
1044
1045 ret = key_seal(new_p, new_o);
1046 if (ret < 0) {
1047 pr_info("trusted_key: key_seal failed (%d)\n", ret);
1048 kfree(new_p);
1049 goto out;
1050 }
1051 if (new_o->pcrlock) {
1052 ret = pcrlock(new_o->pcrlock);
1053 if (ret < 0) {
1054 pr_info("trusted_key: pcrlock failed (%d)\n", ret);
1055 kfree(new_p);
1056 goto out;
1057 }
1058 }
1059 rcu_assign_pointer(key->payload.data, new_p);
1060 call_rcu(&p->rcu, trusted_rcu_free);
1061out:
1062 kfree(datablob);
1063 kfree(new_o);
1064 return ret;
1065}
1066
1067/*
1068 * trusted_read - copy the sealed blob data to userspace in hex.
1069 * On success, return to userspace the trusted key datablob size.
1070 */
1071static long trusted_read(const struct key *key, char __user *buffer,
1072 size_t buflen)
1073{
1074 struct trusted_key_payload *p;
1075 char *ascii_buf;
1076 char *bufp;
1077 int i;
1078
1079 p = rcu_dereference_key(key);
1080 if (!p)
1081 return -EINVAL;
1082 if (!buffer || buflen <= 0)
1083 return 2 * p->blob_len;
1084 ascii_buf = kmalloc(2 * p->blob_len, GFP_KERNEL);
1085 if (!ascii_buf)
1086 return -ENOMEM;
1087
1088 bufp = ascii_buf;
1089 for (i = 0; i < p->blob_len; i++)
1090 bufp = pack_hex_byte(bufp, p->blob[i]);
1091 if ((copy_to_user(buffer, ascii_buf, 2 * p->blob_len)) != 0) {
1092 kfree(ascii_buf);
1093 return -EFAULT;
1094 }
1095 kfree(ascii_buf);
1096 return 2 * p->blob_len;
1097}
1098
1099/*
1100 * trusted_destroy - before freeing the key, clear the decrypted data
1101 */
1102static void trusted_destroy(struct key *key)
1103{
1104 struct trusted_key_payload *p = key->payload.data;
1105
1106 if (!p)
1107 return;
1108 memset(p->key, 0, p->key_len);
1109 kfree(key->payload.data);
1110}
1111
1112struct key_type key_type_trusted = {
1113 .name = "trusted",
1114 .instantiate = trusted_instantiate,
1115 .update = trusted_update,
1116 .match = user_match,
1117 .destroy = trusted_destroy,
1118 .describe = user_describe,
1119 .read = trusted_read,
1120};
1121
1122EXPORT_SYMBOL_GPL(key_type_trusted);
1123
1124static void trusted_shash_release(void)
1125{
1126 if (hashalg)
1127 crypto_free_shash(hashalg);
1128 if (hmacalg)
1129 crypto_free_shash(hmacalg);
1130}
1131
1132static int __init trusted_shash_alloc(void)
1133{
1134 int ret;
1135
1136 hmacalg = crypto_alloc_shash(hmac_alg, 0, CRYPTO_ALG_ASYNC);
1137 if (IS_ERR(hmacalg)) {
1138 pr_info("trusted_key: could not allocate crypto %s\n",
1139 hmac_alg);
1140 return PTR_ERR(hmacalg);
1141 }
1142
1143 hashalg = crypto_alloc_shash(hash_alg, 0, CRYPTO_ALG_ASYNC);
1144 if (IS_ERR(hashalg)) {
1145 pr_info("trusted_key: could not allocate crypto %s\n",
1146 hash_alg);
1147 ret = PTR_ERR(hashalg);
1148 goto hashalg_fail;
1149 }
1150
1151 return 0;
1152
1153hashalg_fail:
1154 crypto_free_shash(hmacalg);
1155 return ret;
1156}
1157
1158static int __init init_trusted(void)
1159{
1160 int ret;
1161
1162 ret = trusted_shash_alloc();
1163 if (ret < 0)
1164 return ret;
1165 ret = register_key_type(&key_type_trusted);
1166 if (ret < 0)
1167 trusted_shash_release();
1168 return ret;
1169}
1170
1171static void __exit cleanup_trusted(void)
1172{
1173 trusted_shash_release();
1174 unregister_key_type(&key_type_trusted);
1175}
1176
1177late_initcall(init_trusted);
1178module_exit(cleanup_trusted);
1179
1180MODULE_LICENSE("GPL");