tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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.rst
12 */
13
14#include <crypto/hash_info.h>
15#include <linux/uaccess.h>
16#include <linux/module.h>
17#include <linux/init.h>
18#include <linux/slab.h>
19#include <linux/parser.h>
20#include <linux/string.h>
21#include <linux/err.h>
22#include <keys/user-type.h>
23#include <keys/trusted-type.h>
24#include <linux/key-type.h>
25#include <linux/rcupdate.h>
26#include <linux/crypto.h>
27#include <crypto/hash.h>
28#include <crypto/sha.h>
29#include <linux/capability.h>
30#include <linux/tpm.h>
31#include <linux/tpm_command.h>
32
33#include "trusted.h"
34
35static const char hmac_alg[] = "hmac(sha1)";
36static const char hash_alg[] = "sha1";
37
38struct sdesc {
39 struct shash_desc shash;
40 char ctx[];
41};
42
43static struct crypto_shash *hashalg;
44static struct crypto_shash *hmacalg;
45
46static struct sdesc *init_sdesc(struct crypto_shash *alg)
47{
48 struct sdesc *sdesc;
49 int size;
50
51 size = sizeof(struct shash_desc) + crypto_shash_descsize(alg);
52 sdesc = kmalloc(size, GFP_KERNEL);
53 if (!sdesc)
54 return ERR_PTR(-ENOMEM);
55 sdesc->shash.tfm = alg;
56 sdesc->shash.flags = 0x0;
57 return sdesc;
58}
59
60static int TSS_sha1(const unsigned char *data, unsigned int datalen,
61 unsigned char *digest)
62{
63 struct sdesc *sdesc;
64 int ret;
65
66 sdesc = init_sdesc(hashalg);
67 if (IS_ERR(sdesc)) {
68 pr_info("trusted_key: can't alloc %s\n", hash_alg);
69 return PTR_ERR(sdesc);
70 }
71
72 ret = crypto_shash_digest(&sdesc->shash, data, datalen, digest);
73 kzfree(sdesc);
74 return ret;
75}
76
77static int TSS_rawhmac(unsigned char *digest, const unsigned char *key,
78 unsigned int keylen, ...)
79{
80 struct sdesc *sdesc;
81 va_list argp;
82 unsigned int dlen;
83 unsigned char *data;
84 int ret;
85
86 sdesc = init_sdesc(hmacalg);
87 if (IS_ERR(sdesc)) {
88 pr_info("trusted_key: can't alloc %s\n", hmac_alg);
89 return PTR_ERR(sdesc);
90 }
91
92 ret = crypto_shash_setkey(hmacalg, key, keylen);
93 if (ret < 0)
94 goto out;
95 ret = crypto_shash_init(&sdesc->shash);
96 if (ret < 0)
97 goto out;
98
99 va_start(argp, keylen);
100 for (;;) {
101 dlen = va_arg(argp, unsigned int);
102 if (dlen == 0)
103 break;
104 data = va_arg(argp, unsigned char *);
105 if (data == NULL) {
106 ret = -EINVAL;
107 break;
108 }
109 ret = crypto_shash_update(&sdesc->shash, data, dlen);
110 if (ret < 0)
111 break;
112 }
113 va_end(argp);
114 if (!ret)
115 ret = crypto_shash_final(&sdesc->shash, digest);
116out:
117 kzfree(sdesc);
118 return ret;
119}
120
121/*
122 * calculate authorization info fields to send to TPM
123 */
124static int TSS_authhmac(unsigned char *digest, const unsigned char *key,
125 unsigned int keylen, unsigned char *h1,
126 unsigned char *h2, unsigned char h3, ...)
127{
128 unsigned char paramdigest[SHA1_DIGEST_SIZE];
129 struct sdesc *sdesc;
130 unsigned int dlen;
131 unsigned char *data;
132 unsigned char c;
133 int ret;
134 va_list argp;
135
136 sdesc = init_sdesc(hashalg);
137 if (IS_ERR(sdesc)) {
138 pr_info("trusted_key: can't alloc %s\n", hash_alg);
139 return PTR_ERR(sdesc);
140 }
141
142 c = h3;
143 ret = crypto_shash_init(&sdesc->shash);
144 if (ret < 0)
145 goto out;
146 va_start(argp, h3);
147 for (;;) {
148 dlen = va_arg(argp, unsigned int);
149 if (dlen == 0)
150 break;
151 data = va_arg(argp, unsigned char *);
152 if (!data) {
153 ret = -EINVAL;
154 break;
155 }
156 ret = crypto_shash_update(&sdesc->shash, data, dlen);
157 if (ret < 0)
158 break;
159 }
160 va_end(argp);
161 if (!ret)
162 ret = crypto_shash_final(&sdesc->shash, paramdigest);
163 if (!ret)
164 ret = TSS_rawhmac(digest, key, keylen, SHA1_DIGEST_SIZE,
165 paramdigest, TPM_NONCE_SIZE, h1,
166 TPM_NONCE_SIZE, h2, 1, &c, 0, 0);
167out:
168 kzfree(sdesc);
169 return ret;
170}
171
172/*
173 * verify the AUTH1_COMMAND (Seal) result from TPM
174 */
175static int TSS_checkhmac1(unsigned char *buffer,
176 const uint32_t command,
177 const unsigned char *ononce,
178 const unsigned char *key,
179 unsigned int keylen, ...)
180{
181 uint32_t bufsize;
182 uint16_t tag;
183 uint32_t ordinal;
184 uint32_t result;
185 unsigned char *enonce;
186 unsigned char *continueflag;
187 unsigned char *authdata;
188 unsigned char testhmac[SHA1_DIGEST_SIZE];
189 unsigned char paramdigest[SHA1_DIGEST_SIZE];
190 struct sdesc *sdesc;
191 unsigned int dlen;
192 unsigned int dpos;
193 va_list argp;
194 int ret;
195
196 bufsize = LOAD32(buffer, TPM_SIZE_OFFSET);
197 tag = LOAD16(buffer, 0);
198 ordinal = command;
199 result = LOAD32N(buffer, TPM_RETURN_OFFSET);
200 if (tag == TPM_TAG_RSP_COMMAND)
201 return 0;
202 if (tag != TPM_TAG_RSP_AUTH1_COMMAND)
203 return -EINVAL;
204 authdata = buffer + bufsize - SHA1_DIGEST_SIZE;
205 continueflag = authdata - 1;
206 enonce = continueflag - TPM_NONCE_SIZE;
207
208 sdesc = init_sdesc(hashalg);
209 if (IS_ERR(sdesc)) {
210 pr_info("trusted_key: can't alloc %s\n", hash_alg);
211 return PTR_ERR(sdesc);
212 }
213 ret = crypto_shash_init(&sdesc->shash);
214 if (ret < 0)
215 goto out;
216 ret = crypto_shash_update(&sdesc->shash, (const u8 *)&result,
217 sizeof result);
218 if (ret < 0)
219 goto out;
220 ret = crypto_shash_update(&sdesc->shash, (const u8 *)&ordinal,
221 sizeof ordinal);
222 if (ret < 0)
223 goto out;
224 va_start(argp, keylen);
225 for (;;) {
226 dlen = va_arg(argp, unsigned int);
227 if (dlen == 0)
228 break;
229 dpos = va_arg(argp, unsigned int);
230 ret = crypto_shash_update(&sdesc->shash, buffer + dpos, dlen);
231 if (ret < 0)
232 break;
233 }
234 va_end(argp);
235 if (!ret)
236 ret = crypto_shash_final(&sdesc->shash, paramdigest);
237 if (ret < 0)
238 goto out;
239
240 ret = TSS_rawhmac(testhmac, key, keylen, SHA1_DIGEST_SIZE, paramdigest,
241 TPM_NONCE_SIZE, enonce, TPM_NONCE_SIZE, ononce,
242 1, continueflag, 0, 0);
243 if (ret < 0)
244 goto out;
245
246 if (memcmp(testhmac, authdata, SHA1_DIGEST_SIZE))
247 ret = -EINVAL;
248out:
249 kzfree(sdesc);
250 return ret;
251}
252
253/*
254 * verify the AUTH2_COMMAND (unseal) result from TPM
255 */
256static int TSS_checkhmac2(unsigned char *buffer,
257 const uint32_t command,
258 const unsigned char *ononce,
259 const unsigned char *key1,
260 unsigned int keylen1,
261 const unsigned char *key2,
262 unsigned int keylen2, ...)
263{
264 uint32_t bufsize;
265 uint16_t tag;
266 uint32_t ordinal;
267 uint32_t result;
268 unsigned char *enonce1;
269 unsigned char *continueflag1;
270 unsigned char *authdata1;
271 unsigned char *enonce2;
272 unsigned char *continueflag2;
273 unsigned char *authdata2;
274 unsigned char testhmac1[SHA1_DIGEST_SIZE];
275 unsigned char testhmac2[SHA1_DIGEST_SIZE];
276 unsigned char paramdigest[SHA1_DIGEST_SIZE];
277 struct sdesc *sdesc;
278 unsigned int dlen;
279 unsigned int dpos;
280 va_list argp;
281 int ret;
282
283 bufsize = LOAD32(buffer, TPM_SIZE_OFFSET);
284 tag = LOAD16(buffer, 0);
285 ordinal = command;
286 result = LOAD32N(buffer, TPM_RETURN_OFFSET);
287
288 if (tag == TPM_TAG_RSP_COMMAND)
289 return 0;
290 if (tag != TPM_TAG_RSP_AUTH2_COMMAND)
291 return -EINVAL;
292 authdata1 = buffer + bufsize - (SHA1_DIGEST_SIZE + 1
293 + SHA1_DIGEST_SIZE + SHA1_DIGEST_SIZE);
294 authdata2 = buffer + bufsize - (SHA1_DIGEST_SIZE);
295 continueflag1 = authdata1 - 1;
296 continueflag2 = authdata2 - 1;
297 enonce1 = continueflag1 - TPM_NONCE_SIZE;
298 enonce2 = continueflag2 - TPM_NONCE_SIZE;
299
300 sdesc = init_sdesc(hashalg);
301 if (IS_ERR(sdesc)) {
302 pr_info("trusted_key: can't alloc %s\n", hash_alg);
303 return PTR_ERR(sdesc);
304 }
305 ret = crypto_shash_init(&sdesc->shash);
306 if (ret < 0)
307 goto out;
308 ret = crypto_shash_update(&sdesc->shash, (const u8 *)&result,
309 sizeof result);
310 if (ret < 0)
311 goto out;
312 ret = crypto_shash_update(&sdesc->shash, (const u8 *)&ordinal,
313 sizeof ordinal);
314 if (ret < 0)
315 goto out;
316
317 va_start(argp, keylen2);
318 for (;;) {
319 dlen = va_arg(argp, unsigned int);
320 if (dlen == 0)
321 break;
322 dpos = va_arg(argp, unsigned int);
323 ret = crypto_shash_update(&sdesc->shash, buffer + dpos, dlen);
324 if (ret < 0)
325 break;
326 }
327 va_end(argp);
328 if (!ret)
329 ret = crypto_shash_final(&sdesc->shash, paramdigest);
330 if (ret < 0)
331 goto out;
332
333 ret = TSS_rawhmac(testhmac1, key1, keylen1, SHA1_DIGEST_SIZE,
334 paramdigest, TPM_NONCE_SIZE, enonce1,
335 TPM_NONCE_SIZE, ononce, 1, continueflag1, 0, 0);
336 if (ret < 0)
337 goto out;
338 if (memcmp(testhmac1, authdata1, SHA1_DIGEST_SIZE)) {
339 ret = -EINVAL;
340 goto out;
341 }
342 ret = TSS_rawhmac(testhmac2, key2, keylen2, SHA1_DIGEST_SIZE,
343 paramdigest, TPM_NONCE_SIZE, enonce2,
344 TPM_NONCE_SIZE, ononce, 1, continueflag2, 0, 0);
345 if (ret < 0)
346 goto out;
347 if (memcmp(testhmac2, authdata2, SHA1_DIGEST_SIZE))
348 ret = -EINVAL;
349out:
350 kzfree(sdesc);
351 return ret;
352}
353
354/*
355 * For key specific tpm requests, we will generate and send our
356 * own TPM command packets using the drivers send function.
357 */
358static int trusted_tpm_send(unsigned char *cmd, size_t buflen)
359{
360 int rc;
361
362 dump_tpm_buf(cmd);
363 rc = tpm_send(NULL, 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(NULL, hash, SHA1_DIGEST_SIZE);
385 if (ret != SHA1_DIGEST_SIZE)
386 return ret;
387 return tpm_pcr_extend(NULL, 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(NULL, 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(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(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(NULL, 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(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 kzfree(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(NULL, 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(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 kzfree(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 kzfree(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 Opt_hash,
715 Opt_policydigest,
716 Opt_policyhandle,
717};
718
719static const match_table_t key_tokens = {
720 {Opt_new, "new"},
721 {Opt_load, "load"},
722 {Opt_update, "update"},
723 {Opt_keyhandle, "keyhandle=%s"},
724 {Opt_keyauth, "keyauth=%s"},
725 {Opt_blobauth, "blobauth=%s"},
726 {Opt_pcrinfo, "pcrinfo=%s"},
727 {Opt_pcrlock, "pcrlock=%s"},
728 {Opt_migratable, "migratable=%s"},
729 {Opt_hash, "hash=%s"},
730 {Opt_policydigest, "policydigest=%s"},
731 {Opt_policyhandle, "policyhandle=%s"},
732 {Opt_err, NULL}
733};
734
735/* can have zero or more token= options */
736static int getoptions(char *c, struct trusted_key_payload *pay,
737 struct trusted_key_options *opt)
738{
739 substring_t args[MAX_OPT_ARGS];
740 char *p = c;
741 int token;
742 int res;
743 unsigned long handle;
744 unsigned long lock;
745 unsigned long token_mask = 0;
746 unsigned int digest_len;
747 int i;
748 int tpm2;
749
750 tpm2 = tpm_is_tpm2(NULL);
751 if (tpm2 < 0)
752 return tpm2;
753
754 opt->hash = tpm2 ? HASH_ALGO_SHA256 : HASH_ALGO_SHA1;
755
756 while ((p = strsep(&c, " \t"))) {
757 if (*p == '\0' || *p == ' ' || *p == '\t')
758 continue;
759 token = match_token(p, key_tokens, args);
760 if (test_and_set_bit(token, &token_mask))
761 return -EINVAL;
762
763 switch (token) {
764 case Opt_pcrinfo:
765 opt->pcrinfo_len = strlen(args[0].from) / 2;
766 if (opt->pcrinfo_len > MAX_PCRINFO_SIZE)
767 return -EINVAL;
768 res = hex2bin(opt->pcrinfo, args[0].from,
769 opt->pcrinfo_len);
770 if (res < 0)
771 return -EINVAL;
772 break;
773 case Opt_keyhandle:
774 res = kstrtoul(args[0].from, 16, &handle);
775 if (res < 0)
776 return -EINVAL;
777 opt->keytype = SEAL_keytype;
778 opt->keyhandle = handle;
779 break;
780 case Opt_keyauth:
781 if (strlen(args[0].from) != 2 * SHA1_DIGEST_SIZE)
782 return -EINVAL;
783 res = hex2bin(opt->keyauth, args[0].from,
784 SHA1_DIGEST_SIZE);
785 if (res < 0)
786 return -EINVAL;
787 break;
788 case Opt_blobauth:
789 if (strlen(args[0].from) != 2 * SHA1_DIGEST_SIZE)
790 return -EINVAL;
791 res = hex2bin(opt->blobauth, args[0].from,
792 SHA1_DIGEST_SIZE);
793 if (res < 0)
794 return -EINVAL;
795 break;
796 case Opt_migratable:
797 if (*args[0].from == '0')
798 pay->migratable = 0;
799 else
800 return -EINVAL;
801 break;
802 case Opt_pcrlock:
803 res = kstrtoul(args[0].from, 10, &lock);
804 if (res < 0)
805 return -EINVAL;
806 opt->pcrlock = lock;
807 break;
808 case Opt_hash:
809 if (test_bit(Opt_policydigest, &token_mask))
810 return -EINVAL;
811 for (i = 0; i < HASH_ALGO__LAST; i++) {
812 if (!strcmp(args[0].from, hash_algo_name[i])) {
813 opt->hash = i;
814 break;
815 }
816 }
817 if (i == HASH_ALGO__LAST)
818 return -EINVAL;
819 if (!tpm2 && i != HASH_ALGO_SHA1) {
820 pr_info("trusted_key: TPM 1.x only supports SHA-1.\n");
821 return -EINVAL;
822 }
823 break;
824 case Opt_policydigest:
825 digest_len = hash_digest_size[opt->hash];
826 if (!tpm2 || strlen(args[0].from) != (2 * digest_len))
827 return -EINVAL;
828 res = hex2bin(opt->policydigest, args[0].from,
829 digest_len);
830 if (res < 0)
831 return -EINVAL;
832 opt->policydigest_len = digest_len;
833 break;
834 case Opt_policyhandle:
835 if (!tpm2)
836 return -EINVAL;
837 res = kstrtoul(args[0].from, 16, &handle);
838 if (res < 0)
839 return -EINVAL;
840 opt->policyhandle = handle;
841 break;
842 default:
843 return -EINVAL;
844 }
845 }
846 return 0;
847}
848
849/*
850 * datablob_parse - parse the keyctl data and fill in the
851 * payload and options structures
852 *
853 * On success returns 0, otherwise -EINVAL.
854 */
855static int datablob_parse(char *datablob, struct trusted_key_payload *p,
856 struct trusted_key_options *o)
857{
858 substring_t args[MAX_OPT_ARGS];
859 long keylen;
860 int ret = -EINVAL;
861 int key_cmd;
862 char *c;
863
864 /* main command */
865 c = strsep(&datablob, " \t");
866 if (!c)
867 return -EINVAL;
868 key_cmd = match_token(c, key_tokens, args);
869 switch (key_cmd) {
870 case Opt_new:
871 /* first argument is key size */
872 c = strsep(&datablob, " \t");
873 if (!c)
874 return -EINVAL;
875 ret = kstrtol(c, 10, &keylen);
876 if (ret < 0 || keylen < MIN_KEY_SIZE || keylen > MAX_KEY_SIZE)
877 return -EINVAL;
878 p->key_len = keylen;
879 ret = getoptions(datablob, p, o);
880 if (ret < 0)
881 return ret;
882 ret = Opt_new;
883 break;
884 case Opt_load:
885 /* first argument is sealed blob */
886 c = strsep(&datablob, " \t");
887 if (!c)
888 return -EINVAL;
889 p->blob_len = strlen(c) / 2;
890 if (p->blob_len > MAX_BLOB_SIZE)
891 return -EINVAL;
892 ret = hex2bin(p->blob, c, p->blob_len);
893 if (ret < 0)
894 return -EINVAL;
895 ret = getoptions(datablob, p, o);
896 if (ret < 0)
897 return ret;
898 ret = Opt_load;
899 break;
900 case Opt_update:
901 /* all arguments are options */
902 ret = getoptions(datablob, p, o);
903 if (ret < 0)
904 return ret;
905 ret = Opt_update;
906 break;
907 case Opt_err:
908 return -EINVAL;
909 break;
910 }
911 return ret;
912}
913
914static struct trusted_key_options *trusted_options_alloc(void)
915{
916 struct trusted_key_options *options;
917 int tpm2;
918
919 tpm2 = tpm_is_tpm2(NULL);
920 if (tpm2 < 0)
921 return NULL;
922
923 options = kzalloc(sizeof *options, GFP_KERNEL);
924 if (options) {
925 /* set any non-zero defaults */
926 options->keytype = SRK_keytype;
927
928 if (!tpm2)
929 options->keyhandle = SRKHANDLE;
930 }
931 return options;
932}
933
934static struct trusted_key_payload *trusted_payload_alloc(struct key *key)
935{
936 struct trusted_key_payload *p = NULL;
937 int ret;
938
939 ret = key_payload_reserve(key, sizeof *p);
940 if (ret < 0)
941 return p;
942 p = kzalloc(sizeof *p, GFP_KERNEL);
943 if (p)
944 p->migratable = 1; /* migratable by default */
945 return p;
946}
947
948/*
949 * trusted_instantiate - create a new trusted key
950 *
951 * Unseal an existing trusted blob or, for a new key, get a
952 * random key, then seal and create a trusted key-type key,
953 * adding it to the specified keyring.
954 *
955 * On success, return 0. Otherwise return errno.
956 */
957static int trusted_instantiate(struct key *key,
958 struct key_preparsed_payload *prep)
959{
960 struct trusted_key_payload *payload = NULL;
961 struct trusted_key_options *options = NULL;
962 size_t datalen = prep->datalen;
963 char *datablob;
964 int ret = 0;
965 int key_cmd;
966 size_t key_len;
967 int tpm2;
968
969 tpm2 = tpm_is_tpm2(NULL);
970 if (tpm2 < 0)
971 return tpm2;
972
973 if (datalen <= 0 || datalen > 32767 || !prep->data)
974 return -EINVAL;
975
976 datablob = kmalloc(datalen + 1, GFP_KERNEL);
977 if (!datablob)
978 return -ENOMEM;
979 memcpy(datablob, prep->data, datalen);
980 datablob[datalen] = '\0';
981
982 options = trusted_options_alloc();
983 if (!options) {
984 ret = -ENOMEM;
985 goto out;
986 }
987 payload = trusted_payload_alloc(key);
988 if (!payload) {
989 ret = -ENOMEM;
990 goto out;
991 }
992
993 key_cmd = datablob_parse(datablob, payload, options);
994 if (key_cmd < 0) {
995 ret = key_cmd;
996 goto out;
997 }
998
999 if (!options->keyhandle) {
1000 ret = -EINVAL;
1001 goto out;
1002 }
1003
1004 dump_payload(payload);
1005 dump_options(options);
1006
1007 switch (key_cmd) {
1008 case Opt_load:
1009 if (tpm2)
1010 ret = tpm_unseal_trusted(NULL, payload, options);
1011 else
1012 ret = key_unseal(payload, options);
1013 dump_payload(payload);
1014 dump_options(options);
1015 if (ret < 0)
1016 pr_info("trusted_key: key_unseal failed (%d)\n", ret);
1017 break;
1018 case Opt_new:
1019 key_len = payload->key_len;
1020 ret = tpm_get_random(NULL, payload->key, key_len);
1021 if (ret != key_len) {
1022 pr_info("trusted_key: key_create failed (%d)\n", ret);
1023 goto out;
1024 }
1025 if (tpm2)
1026 ret = tpm_seal_trusted(NULL, payload, options);
1027 else
1028 ret = key_seal(payload, options);
1029 if (ret < 0)
1030 pr_info("trusted_key: key_seal failed (%d)\n", ret);
1031 break;
1032 default:
1033 ret = -EINVAL;
1034 goto out;
1035 }
1036 if (!ret && options->pcrlock)
1037 ret = pcrlock(options->pcrlock);
1038out:
1039 kzfree(datablob);
1040 kzfree(options);
1041 if (!ret)
1042 rcu_assign_keypointer(key, payload);
1043 else
1044 kzfree(payload);
1045 return ret;
1046}
1047
1048static void trusted_rcu_free(struct rcu_head *rcu)
1049{
1050 struct trusted_key_payload *p;
1051
1052 p = container_of(rcu, struct trusted_key_payload, rcu);
1053 kzfree(p);
1054}
1055
1056/*
1057 * trusted_update - reseal an existing key with new PCR values
1058 */
1059static int trusted_update(struct key *key, struct key_preparsed_payload *prep)
1060{
1061 struct trusted_key_payload *p;
1062 struct trusted_key_payload *new_p;
1063 struct trusted_key_options *new_o;
1064 size_t datalen = prep->datalen;
1065 char *datablob;
1066 int ret = 0;
1067
1068 if (key_is_negative(key))
1069 return -ENOKEY;
1070 p = key->payload.data[0];
1071 if (!p->migratable)
1072 return -EPERM;
1073 if (datalen <= 0 || datalen > 32767 || !prep->data)
1074 return -EINVAL;
1075
1076 datablob = kmalloc(datalen + 1, GFP_KERNEL);
1077 if (!datablob)
1078 return -ENOMEM;
1079 new_o = trusted_options_alloc();
1080 if (!new_o) {
1081 ret = -ENOMEM;
1082 goto out;
1083 }
1084 new_p = trusted_payload_alloc(key);
1085 if (!new_p) {
1086 ret = -ENOMEM;
1087 goto out;
1088 }
1089
1090 memcpy(datablob, prep->data, datalen);
1091 datablob[datalen] = '\0';
1092 ret = datablob_parse(datablob, new_p, new_o);
1093 if (ret != Opt_update) {
1094 ret = -EINVAL;
1095 kzfree(new_p);
1096 goto out;
1097 }
1098
1099 if (!new_o->keyhandle) {
1100 ret = -EINVAL;
1101 kzfree(new_p);
1102 goto out;
1103 }
1104
1105 /* copy old key values, and reseal with new pcrs */
1106 new_p->migratable = p->migratable;
1107 new_p->key_len = p->key_len;
1108 memcpy(new_p->key, p->key, p->key_len);
1109 dump_payload(p);
1110 dump_payload(new_p);
1111
1112 ret = key_seal(new_p, new_o);
1113 if (ret < 0) {
1114 pr_info("trusted_key: key_seal failed (%d)\n", ret);
1115 kzfree(new_p);
1116 goto out;
1117 }
1118 if (new_o->pcrlock) {
1119 ret = pcrlock(new_o->pcrlock);
1120 if (ret < 0) {
1121 pr_info("trusted_key: pcrlock failed (%d)\n", ret);
1122 kzfree(new_p);
1123 goto out;
1124 }
1125 }
1126 rcu_assign_keypointer(key, new_p);
1127 call_rcu(&p->rcu, trusted_rcu_free);
1128out:
1129 kzfree(datablob);
1130 kzfree(new_o);
1131 return ret;
1132}
1133
1134/*
1135 * trusted_read - copy the sealed blob data to userspace in hex.
1136 * On success, return to userspace the trusted key datablob size.
1137 */
1138static long trusted_read(const struct key *key, char __user *buffer,
1139 size_t buflen)
1140{
1141 const struct trusted_key_payload *p;
1142 char *ascii_buf;
1143 char *bufp;
1144 int i;
1145
1146 p = dereference_key_locked(key);
1147 if (!p)
1148 return -EINVAL;
1149
1150 if (buffer && buflen >= 2 * p->blob_len) {
1151 ascii_buf = kmalloc_array(2, p->blob_len, GFP_KERNEL);
1152 if (!ascii_buf)
1153 return -ENOMEM;
1154
1155 bufp = ascii_buf;
1156 for (i = 0; i < p->blob_len; i++)
1157 bufp = hex_byte_pack(bufp, p->blob[i]);
1158 if (copy_to_user(buffer, ascii_buf, 2 * p->blob_len) != 0) {
1159 kzfree(ascii_buf);
1160 return -EFAULT;
1161 }
1162 kzfree(ascii_buf);
1163 }
1164 return 2 * p->blob_len;
1165}
1166
1167/*
1168 * trusted_destroy - clear and free the key's payload
1169 */
1170static void trusted_destroy(struct key *key)
1171{
1172 kzfree(key->payload.data[0]);
1173}
1174
1175struct key_type key_type_trusted = {
1176 .name = "trusted",
1177 .instantiate = trusted_instantiate,
1178 .update = trusted_update,
1179 .destroy = trusted_destroy,
1180 .describe = user_describe,
1181 .read = trusted_read,
1182};
1183
1184EXPORT_SYMBOL_GPL(key_type_trusted);
1185
1186static void trusted_shash_release(void)
1187{
1188 if (hashalg)
1189 crypto_free_shash(hashalg);
1190 if (hmacalg)
1191 crypto_free_shash(hmacalg);
1192}
1193
1194static int __init trusted_shash_alloc(void)
1195{
1196 int ret;
1197
1198 hmacalg = crypto_alloc_shash(hmac_alg, 0, CRYPTO_ALG_ASYNC);
1199 if (IS_ERR(hmacalg)) {
1200 pr_info("trusted_key: could not allocate crypto %s\n",
1201 hmac_alg);
1202 return PTR_ERR(hmacalg);
1203 }
1204
1205 hashalg = crypto_alloc_shash(hash_alg, 0, CRYPTO_ALG_ASYNC);
1206 if (IS_ERR(hashalg)) {
1207 pr_info("trusted_key: could not allocate crypto %s\n",
1208 hash_alg);
1209 ret = PTR_ERR(hashalg);
1210 goto hashalg_fail;
1211 }
1212
1213 return 0;
1214
1215hashalg_fail:
1216 crypto_free_shash(hmacalg);
1217 return ret;
1218}
1219
1220static int __init init_trusted(void)
1221{
1222 int ret;
1223
1224 ret = trusted_shash_alloc();
1225 if (ret < 0)
1226 return ret;
1227 ret = register_key_type(&key_type_trusted);
1228 if (ret < 0)
1229 trusted_shash_release();
1230 return ret;
1231}
1232
1233static void __exit cleanup_trusted(void)
1234{
1235 trusted_shash_release();
1236 unregister_key_type(&key_type_trusted);
1237}
1238
1239late_initcall(init_trusted);
1240module_exit(cleanup_trusted);
1241
1242MODULE_LICENSE("GPL");