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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 * 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 */
377static 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 */
393static 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 */
428static 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
446struct 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 */
458static 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 }
565out:
566 kfree(td);
567 return ret;
568}
569
570/*
571 * use the AUTH2_COMMAND form of unseal, to authorize both key and blob
572 */
573static 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 */
661static 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 */
687static 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
709enum {
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
716static 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 */
730static 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 = kstrtoul(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 = kstrtoul(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 */
803static 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 = kstrtol(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
862static 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
875static 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 */
898static 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);
963out:
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
973static 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 */
985static 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);
1044out:
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 */
1054static 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 */
1085static 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
1095struct 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
1105EXPORT_SYMBOL_GPL(key_type_trusted);
1106
1107static void trusted_shash_release(void)
1108{
1109 if (hashalg)
1110 crypto_free_shash(hashalg);
1111 if (hmacalg)
1112 crypto_free_shash(hmacalg);
1113}
1114
1115static 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
1136hashalg_fail:
1137 crypto_free_shash(hmacalg);
1138 return ret;
1139}
1140
1141static 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
1154static void __exit cleanup_trusted(void)
1155{
1156 trusted_shash_release();
1157 unregister_key_type(&key_type_trusted);
1158}
1159
1160late_initcall(init_trusted);
1161module_exit(cleanup_trusted);
1162
1163MODULE_LICENSE("GPL");