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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2010 IBM Corporation
4 *
5 * Author:
6 * David Safford <safford@us.ibm.com>
7 *
8 * See Documentation/security/keys/trusted-encrypted.rst
9 */
10
11#include <crypto/hash_info.h>
12#include <linux/uaccess.h>
13#include <linux/module.h>
14#include <linux/init.h>
15#include <linux/slab.h>
16#include <linux/parser.h>
17#include <linux/string.h>
18#include <linux/err.h>
19#include <keys/user-type.h>
20#include <keys/trusted-type.h>
21#include <linux/key-type.h>
22#include <linux/rcupdate.h>
23#include <linux/crypto.h>
24#include <crypto/hash.h>
25#include <crypto/sha.h>
26#include <linux/capability.h>
27#include <linux/tpm.h>
28#include <linux/tpm_command.h>
29
30#include <keys/trusted_tpm.h>
31
32static const char hmac_alg[] = "hmac(sha1)";
33static const char hash_alg[] = "sha1";
34static struct tpm_chip *chip;
35static struct tpm_digest *digests;
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 return sdesc;
56}
57
58static int TSS_sha1(const unsigned char *data, unsigned int datalen,
59 unsigned char *digest)
60{
61 struct sdesc *sdesc;
62 int ret;
63
64 sdesc = init_sdesc(hashalg);
65 if (IS_ERR(sdesc)) {
66 pr_info("trusted_key: can't alloc %s\n", hash_alg);
67 return PTR_ERR(sdesc);
68 }
69
70 ret = crypto_shash_digest(&sdesc->shash, data, datalen, digest);
71 kfree_sensitive(sdesc);
72 return ret;
73}
74
75static int TSS_rawhmac(unsigned char *digest, const unsigned char *key,
76 unsigned int keylen, ...)
77{
78 struct sdesc *sdesc;
79 va_list argp;
80 unsigned int dlen;
81 unsigned char *data;
82 int ret;
83
84 sdesc = init_sdesc(hmacalg);
85 if (IS_ERR(sdesc)) {
86 pr_info("trusted_key: can't alloc %s\n", hmac_alg);
87 return PTR_ERR(sdesc);
88 }
89
90 ret = crypto_shash_setkey(hmacalg, key, keylen);
91 if (ret < 0)
92 goto out;
93 ret = crypto_shash_init(&sdesc->shash);
94 if (ret < 0)
95 goto out;
96
97 va_start(argp, keylen);
98 for (;;) {
99 dlen = va_arg(argp, unsigned int);
100 if (dlen == 0)
101 break;
102 data = va_arg(argp, unsigned char *);
103 if (data == NULL) {
104 ret = -EINVAL;
105 break;
106 }
107 ret = crypto_shash_update(&sdesc->shash, data, dlen);
108 if (ret < 0)
109 break;
110 }
111 va_end(argp);
112 if (!ret)
113 ret = crypto_shash_final(&sdesc->shash, digest);
114out:
115 kfree_sensitive(sdesc);
116 return ret;
117}
118
119/*
120 * calculate authorization info fields to send to TPM
121 */
122int TSS_authhmac(unsigned char *digest, const unsigned char *key,
123 unsigned int keylen, unsigned char *h1,
124 unsigned char *h2, unsigned int h3, ...)
125{
126 unsigned char paramdigest[SHA1_DIGEST_SIZE];
127 struct sdesc *sdesc;
128 unsigned int dlen;
129 unsigned char *data;
130 unsigned char c;
131 int ret;
132 va_list argp;
133
134 if (!chip)
135 return -ENODEV;
136
137 sdesc = init_sdesc(hashalg);
138 if (IS_ERR(sdesc)) {
139 pr_info("trusted_key: can't alloc %s\n", hash_alg);
140 return PTR_ERR(sdesc);
141 }
142
143 c = !!h3;
144 ret = crypto_shash_init(&sdesc->shash);
145 if (ret < 0)
146 goto out;
147 va_start(argp, h3);
148 for (;;) {
149 dlen = va_arg(argp, unsigned int);
150 if (dlen == 0)
151 break;
152 data = va_arg(argp, unsigned char *);
153 if (!data) {
154 ret = -EINVAL;
155 break;
156 }
157 ret = crypto_shash_update(&sdesc->shash, data, dlen);
158 if (ret < 0)
159 break;
160 }
161 va_end(argp);
162 if (!ret)
163 ret = crypto_shash_final(&sdesc->shash, paramdigest);
164 if (!ret)
165 ret = TSS_rawhmac(digest, key, keylen, SHA1_DIGEST_SIZE,
166 paramdigest, TPM_NONCE_SIZE, h1,
167 TPM_NONCE_SIZE, h2, 1, &c, 0, 0);
168out:
169 kfree_sensitive(sdesc);
170 return ret;
171}
172EXPORT_SYMBOL_GPL(TSS_authhmac);
173
174/*
175 * verify the AUTH1_COMMAND (Seal) result from TPM
176 */
177int TSS_checkhmac1(unsigned char *buffer,
178 const uint32_t command,
179 const unsigned char *ononce,
180 const unsigned char *key,
181 unsigned int keylen, ...)
182{
183 uint32_t bufsize;
184 uint16_t tag;
185 uint32_t ordinal;
186 uint32_t result;
187 unsigned char *enonce;
188 unsigned char *continueflag;
189 unsigned char *authdata;
190 unsigned char testhmac[SHA1_DIGEST_SIZE];
191 unsigned char paramdigest[SHA1_DIGEST_SIZE];
192 struct sdesc *sdesc;
193 unsigned int dlen;
194 unsigned int dpos;
195 va_list argp;
196 int ret;
197
198 if (!chip)
199 return -ENODEV;
200
201 bufsize = LOAD32(buffer, TPM_SIZE_OFFSET);
202 tag = LOAD16(buffer, 0);
203 ordinal = command;
204 result = LOAD32N(buffer, TPM_RETURN_OFFSET);
205 if (tag == TPM_TAG_RSP_COMMAND)
206 return 0;
207 if (tag != TPM_TAG_RSP_AUTH1_COMMAND)
208 return -EINVAL;
209 authdata = buffer + bufsize - SHA1_DIGEST_SIZE;
210 continueflag = authdata - 1;
211 enonce = continueflag - TPM_NONCE_SIZE;
212
213 sdesc = init_sdesc(hashalg);
214 if (IS_ERR(sdesc)) {
215 pr_info("trusted_key: can't alloc %s\n", hash_alg);
216 return PTR_ERR(sdesc);
217 }
218 ret = crypto_shash_init(&sdesc->shash);
219 if (ret < 0)
220 goto out;
221 ret = crypto_shash_update(&sdesc->shash, (const u8 *)&result,
222 sizeof result);
223 if (ret < 0)
224 goto out;
225 ret = crypto_shash_update(&sdesc->shash, (const u8 *)&ordinal,
226 sizeof ordinal);
227 if (ret < 0)
228 goto out;
229 va_start(argp, keylen);
230 for (;;) {
231 dlen = va_arg(argp, unsigned int);
232 if (dlen == 0)
233 break;
234 dpos = va_arg(argp, unsigned int);
235 ret = crypto_shash_update(&sdesc->shash, buffer + dpos, dlen);
236 if (ret < 0)
237 break;
238 }
239 va_end(argp);
240 if (!ret)
241 ret = crypto_shash_final(&sdesc->shash, paramdigest);
242 if (ret < 0)
243 goto out;
244
245 ret = TSS_rawhmac(testhmac, key, keylen, SHA1_DIGEST_SIZE, paramdigest,
246 TPM_NONCE_SIZE, enonce, TPM_NONCE_SIZE, ononce,
247 1, continueflag, 0, 0);
248 if (ret < 0)
249 goto out;
250
251 if (memcmp(testhmac, authdata, SHA1_DIGEST_SIZE))
252 ret = -EINVAL;
253out:
254 kfree_sensitive(sdesc);
255 return ret;
256}
257EXPORT_SYMBOL_GPL(TSS_checkhmac1);
258
259/*
260 * verify the AUTH2_COMMAND (unseal) result from TPM
261 */
262static int TSS_checkhmac2(unsigned char *buffer,
263 const uint32_t command,
264 const unsigned char *ononce,
265 const unsigned char *key1,
266 unsigned int keylen1,
267 const unsigned char *key2,
268 unsigned int keylen2, ...)
269{
270 uint32_t bufsize;
271 uint16_t tag;
272 uint32_t ordinal;
273 uint32_t result;
274 unsigned char *enonce1;
275 unsigned char *continueflag1;
276 unsigned char *authdata1;
277 unsigned char *enonce2;
278 unsigned char *continueflag2;
279 unsigned char *authdata2;
280 unsigned char testhmac1[SHA1_DIGEST_SIZE];
281 unsigned char testhmac2[SHA1_DIGEST_SIZE];
282 unsigned char paramdigest[SHA1_DIGEST_SIZE];
283 struct sdesc *sdesc;
284 unsigned int dlen;
285 unsigned int dpos;
286 va_list argp;
287 int ret;
288
289 bufsize = LOAD32(buffer, TPM_SIZE_OFFSET);
290 tag = LOAD16(buffer, 0);
291 ordinal = command;
292 result = LOAD32N(buffer, TPM_RETURN_OFFSET);
293
294 if (tag == TPM_TAG_RSP_COMMAND)
295 return 0;
296 if (tag != TPM_TAG_RSP_AUTH2_COMMAND)
297 return -EINVAL;
298 authdata1 = buffer + bufsize - (SHA1_DIGEST_SIZE + 1
299 + SHA1_DIGEST_SIZE + SHA1_DIGEST_SIZE);
300 authdata2 = buffer + bufsize - (SHA1_DIGEST_SIZE);
301 continueflag1 = authdata1 - 1;
302 continueflag2 = authdata2 - 1;
303 enonce1 = continueflag1 - TPM_NONCE_SIZE;
304 enonce2 = continueflag2 - TPM_NONCE_SIZE;
305
306 sdesc = init_sdesc(hashalg);
307 if (IS_ERR(sdesc)) {
308 pr_info("trusted_key: can't alloc %s\n", hash_alg);
309 return PTR_ERR(sdesc);
310 }
311 ret = crypto_shash_init(&sdesc->shash);
312 if (ret < 0)
313 goto out;
314 ret = crypto_shash_update(&sdesc->shash, (const u8 *)&result,
315 sizeof result);
316 if (ret < 0)
317 goto out;
318 ret = crypto_shash_update(&sdesc->shash, (const u8 *)&ordinal,
319 sizeof ordinal);
320 if (ret < 0)
321 goto out;
322
323 va_start(argp, keylen2);
324 for (;;) {
325 dlen = va_arg(argp, unsigned int);
326 if (dlen == 0)
327 break;
328 dpos = va_arg(argp, unsigned int);
329 ret = crypto_shash_update(&sdesc->shash, buffer + dpos, dlen);
330 if (ret < 0)
331 break;
332 }
333 va_end(argp);
334 if (!ret)
335 ret = crypto_shash_final(&sdesc->shash, paramdigest);
336 if (ret < 0)
337 goto out;
338
339 ret = TSS_rawhmac(testhmac1, key1, keylen1, SHA1_DIGEST_SIZE,
340 paramdigest, TPM_NONCE_SIZE, enonce1,
341 TPM_NONCE_SIZE, ononce, 1, continueflag1, 0, 0);
342 if (ret < 0)
343 goto out;
344 if (memcmp(testhmac1, authdata1, SHA1_DIGEST_SIZE)) {
345 ret = -EINVAL;
346 goto out;
347 }
348 ret = TSS_rawhmac(testhmac2, key2, keylen2, SHA1_DIGEST_SIZE,
349 paramdigest, TPM_NONCE_SIZE, enonce2,
350 TPM_NONCE_SIZE, ononce, 1, continueflag2, 0, 0);
351 if (ret < 0)
352 goto out;
353 if (memcmp(testhmac2, authdata2, SHA1_DIGEST_SIZE))
354 ret = -EINVAL;
355out:
356 kfree_sensitive(sdesc);
357 return ret;
358}
359
360/*
361 * For key specific tpm requests, we will generate and send our
362 * own TPM command packets using the drivers send function.
363 */
364int trusted_tpm_send(unsigned char *cmd, size_t buflen)
365{
366 int rc;
367
368 if (!chip)
369 return -ENODEV;
370
371 dump_tpm_buf(cmd);
372 rc = tpm_send(chip, cmd, buflen);
373 dump_tpm_buf(cmd);
374 if (rc > 0)
375 /* Can't return positive return codes values to keyctl */
376 rc = -EPERM;
377 return rc;
378}
379EXPORT_SYMBOL_GPL(trusted_tpm_send);
380
381/*
382 * Lock a trusted key, by extending a selected PCR.
383 *
384 * Prevents a trusted key that is sealed to PCRs from being accessed.
385 * This uses the tpm driver's extend function.
386 */
387static int pcrlock(const int pcrnum)
388{
389 if (!capable(CAP_SYS_ADMIN))
390 return -EPERM;
391
392 return tpm_pcr_extend(chip, pcrnum, digests) ? -EINVAL : 0;
393}
394
395/*
396 * Create an object specific authorisation protocol (OSAP) session
397 */
398static int osap(struct tpm_buf *tb, struct osapsess *s,
399 const unsigned char *key, uint16_t type, uint32_t handle)
400{
401 unsigned char enonce[TPM_NONCE_SIZE];
402 unsigned char ononce[TPM_NONCE_SIZE];
403 int ret;
404
405 ret = tpm_get_random(chip, ononce, TPM_NONCE_SIZE);
406 if (ret != TPM_NONCE_SIZE)
407 return ret;
408
409 tpm_buf_reset(tb, TPM_TAG_RQU_COMMAND, TPM_ORD_OSAP);
410 tpm_buf_append_u16(tb, type);
411 tpm_buf_append_u32(tb, handle);
412 tpm_buf_append(tb, ononce, TPM_NONCE_SIZE);
413
414 ret = trusted_tpm_send(tb->data, MAX_BUF_SIZE);
415 if (ret < 0)
416 return ret;
417
418 s->handle = LOAD32(tb->data, TPM_DATA_OFFSET);
419 memcpy(s->enonce, &(tb->data[TPM_DATA_OFFSET + sizeof(uint32_t)]),
420 TPM_NONCE_SIZE);
421 memcpy(enonce, &(tb->data[TPM_DATA_OFFSET + sizeof(uint32_t) +
422 TPM_NONCE_SIZE]), TPM_NONCE_SIZE);
423 return TSS_rawhmac(s->secret, key, SHA1_DIGEST_SIZE, TPM_NONCE_SIZE,
424 enonce, TPM_NONCE_SIZE, ononce, 0, 0);
425}
426
427/*
428 * Create an object independent authorisation protocol (oiap) session
429 */
430int oiap(struct tpm_buf *tb, uint32_t *handle, unsigned char *nonce)
431{
432 int ret;
433
434 if (!chip)
435 return -ENODEV;
436
437 tpm_buf_reset(tb, TPM_TAG_RQU_COMMAND, TPM_ORD_OIAP);
438 ret = trusted_tpm_send(tb->data, MAX_BUF_SIZE);
439 if (ret < 0)
440 return ret;
441
442 *handle = LOAD32(tb->data, TPM_DATA_OFFSET);
443 memcpy(nonce, &tb->data[TPM_DATA_OFFSET + sizeof(uint32_t)],
444 TPM_NONCE_SIZE);
445 return 0;
446}
447EXPORT_SYMBOL_GPL(oiap);
448
449struct tpm_digests {
450 unsigned char encauth[SHA1_DIGEST_SIZE];
451 unsigned char pubauth[SHA1_DIGEST_SIZE];
452 unsigned char xorwork[SHA1_DIGEST_SIZE * 2];
453 unsigned char xorhash[SHA1_DIGEST_SIZE];
454 unsigned char nonceodd[TPM_NONCE_SIZE];
455};
456
457/*
458 * Have the TPM seal(encrypt) the trusted key, possibly based on
459 * Platform Configuration Registers (PCRs). AUTH1 for sealing key.
460 */
461static int tpm_seal(struct tpm_buf *tb, uint16_t keytype,
462 uint32_t keyhandle, const unsigned char *keyauth,
463 const unsigned char *data, uint32_t datalen,
464 unsigned char *blob, uint32_t *bloblen,
465 const unsigned char *blobauth,
466 const unsigned char *pcrinfo, uint32_t pcrinfosize)
467{
468 struct osapsess sess;
469 struct tpm_digests *td;
470 unsigned char cont;
471 uint32_t ordinal;
472 uint32_t pcrsize;
473 uint32_t datsize;
474 int sealinfosize;
475 int encdatasize;
476 int storedsize;
477 int ret;
478 int i;
479
480 /* alloc some work space for all the hashes */
481 td = kmalloc(sizeof *td, GFP_KERNEL);
482 if (!td)
483 return -ENOMEM;
484
485 /* get session for sealing key */
486 ret = osap(tb, &sess, keyauth, keytype, keyhandle);
487 if (ret < 0)
488 goto out;
489 dump_sess(&sess);
490
491 /* calculate encrypted authorization value */
492 memcpy(td->xorwork, sess.secret, SHA1_DIGEST_SIZE);
493 memcpy(td->xorwork + SHA1_DIGEST_SIZE, sess.enonce, SHA1_DIGEST_SIZE);
494 ret = TSS_sha1(td->xorwork, SHA1_DIGEST_SIZE * 2, td->xorhash);
495 if (ret < 0)
496 goto out;
497
498 ret = tpm_get_random(chip, td->nonceodd, TPM_NONCE_SIZE);
499 if (ret != TPM_NONCE_SIZE)
500 goto out;
501 ordinal = htonl(TPM_ORD_SEAL);
502 datsize = htonl(datalen);
503 pcrsize = htonl(pcrinfosize);
504 cont = 0;
505
506 /* encrypt data authorization key */
507 for (i = 0; i < SHA1_DIGEST_SIZE; ++i)
508 td->encauth[i] = td->xorhash[i] ^ blobauth[i];
509
510 /* calculate authorization HMAC value */
511 if (pcrinfosize == 0) {
512 /* no pcr info specified */
513 ret = TSS_authhmac(td->pubauth, sess.secret, SHA1_DIGEST_SIZE,
514 sess.enonce, td->nonceodd, cont,
515 sizeof(uint32_t), &ordinal, SHA1_DIGEST_SIZE,
516 td->encauth, sizeof(uint32_t), &pcrsize,
517 sizeof(uint32_t), &datsize, datalen, data, 0,
518 0);
519 } else {
520 /* pcr info specified */
521 ret = TSS_authhmac(td->pubauth, sess.secret, SHA1_DIGEST_SIZE,
522 sess.enonce, td->nonceodd, cont,
523 sizeof(uint32_t), &ordinal, SHA1_DIGEST_SIZE,
524 td->encauth, sizeof(uint32_t), &pcrsize,
525 pcrinfosize, pcrinfo, sizeof(uint32_t),
526 &datsize, datalen, data, 0, 0);
527 }
528 if (ret < 0)
529 goto out;
530
531 /* build and send the TPM request packet */
532 tpm_buf_reset(tb, TPM_TAG_RQU_AUTH1_COMMAND, TPM_ORD_SEAL);
533 tpm_buf_append_u32(tb, keyhandle);
534 tpm_buf_append(tb, td->encauth, SHA1_DIGEST_SIZE);
535 tpm_buf_append_u32(tb, pcrinfosize);
536 tpm_buf_append(tb, pcrinfo, pcrinfosize);
537 tpm_buf_append_u32(tb, datalen);
538 tpm_buf_append(tb, data, datalen);
539 tpm_buf_append_u32(tb, sess.handle);
540 tpm_buf_append(tb, td->nonceodd, TPM_NONCE_SIZE);
541 tpm_buf_append_u8(tb, cont);
542 tpm_buf_append(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 kfree_sensitive(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 int ret;
589
590 /* sessions for unsealing key and data */
591 ret = oiap(tb, &authhandle1, enonce1);
592 if (ret < 0) {
593 pr_info("trusted_key: oiap failed (%d)\n", ret);
594 return ret;
595 }
596 ret = oiap(tb, &authhandle2, enonce2);
597 if (ret < 0) {
598 pr_info("trusted_key: oiap failed (%d)\n", ret);
599 return ret;
600 }
601
602 ordinal = htonl(TPM_ORD_UNSEAL);
603 ret = tpm_get_random(chip, nonceodd, TPM_NONCE_SIZE);
604 if (ret != TPM_NONCE_SIZE) {
605 pr_info("trusted_key: tpm_get_random failed (%d)\n", ret);
606 return ret;
607 }
608 ret = TSS_authhmac(authdata1, keyauth, TPM_NONCE_SIZE,
609 enonce1, nonceodd, cont, sizeof(uint32_t),
610 &ordinal, bloblen, blob, 0, 0);
611 if (ret < 0)
612 return ret;
613 ret = TSS_authhmac(authdata2, blobauth, TPM_NONCE_SIZE,
614 enonce2, nonceodd, cont, sizeof(uint32_t),
615 &ordinal, bloblen, blob, 0, 0);
616 if (ret < 0)
617 return ret;
618
619 /* build and send TPM request packet */
620 tpm_buf_reset(tb, TPM_TAG_RQU_AUTH2_COMMAND, TPM_ORD_UNSEAL);
621 tpm_buf_append_u32(tb, keyhandle);
622 tpm_buf_append(tb, blob, bloblen);
623 tpm_buf_append_u32(tb, authhandle1);
624 tpm_buf_append(tb, nonceodd, TPM_NONCE_SIZE);
625 tpm_buf_append_u8(tb, cont);
626 tpm_buf_append(tb, authdata1, SHA1_DIGEST_SIZE);
627 tpm_buf_append_u32(tb, authhandle2);
628 tpm_buf_append(tb, nonceodd, TPM_NONCE_SIZE);
629 tpm_buf_append_u8(tb, cont);
630 tpm_buf_append(tb, authdata2, SHA1_DIGEST_SIZE);
631
632 ret = trusted_tpm_send(tb->data, MAX_BUF_SIZE);
633 if (ret < 0) {
634 pr_info("trusted_key: authhmac failed (%d)\n", ret);
635 return ret;
636 }
637
638 *datalen = LOAD32(tb->data, TPM_DATA_OFFSET);
639 ret = TSS_checkhmac2(tb->data, ordinal, nonceodd,
640 keyauth, SHA1_DIGEST_SIZE,
641 blobauth, SHA1_DIGEST_SIZE,
642 sizeof(uint32_t), TPM_DATA_OFFSET,
643 *datalen, TPM_DATA_OFFSET + sizeof(uint32_t), 0,
644 0);
645 if (ret < 0) {
646 pr_info("trusted_key: TSS_checkhmac2 failed (%d)\n", ret);
647 return ret;
648 }
649 memcpy(data, tb->data + TPM_DATA_OFFSET + sizeof(uint32_t), *datalen);
650 return 0;
651}
652
653/*
654 * Have the TPM seal(encrypt) the symmetric key
655 */
656static int key_seal(struct trusted_key_payload *p,
657 struct trusted_key_options *o)
658{
659 struct tpm_buf tb;
660 int ret;
661
662 ret = tpm_buf_init(&tb, 0, 0);
663 if (ret)
664 return ret;
665
666 /* include migratable flag at end of sealed key */
667 p->key[p->key_len] = p->migratable;
668
669 ret = tpm_seal(&tb, o->keytype, o->keyhandle, o->keyauth,
670 p->key, p->key_len + 1, p->blob, &p->blob_len,
671 o->blobauth, o->pcrinfo, o->pcrinfo_len);
672 if (ret < 0)
673 pr_info("trusted_key: srkseal failed (%d)\n", ret);
674
675 tpm_buf_destroy(&tb);
676 return ret;
677}
678
679/*
680 * Have the TPM unseal(decrypt) the symmetric key
681 */
682static int key_unseal(struct trusted_key_payload *p,
683 struct trusted_key_options *o)
684{
685 struct tpm_buf tb;
686 int ret;
687
688 ret = tpm_buf_init(&tb, 0, 0);
689 if (ret)
690 return ret;
691
692 ret = tpm_unseal(&tb, o->keyhandle, o->keyauth, p->blob, p->blob_len,
693 o->blobauth, p->key, &p->key_len);
694 if (ret < 0)
695 pr_info("trusted_key: srkunseal failed (%d)\n", ret);
696 else
697 /* pull migratable flag out of sealed key */
698 p->migratable = p->key[--p->key_len];
699
700 tpm_buf_destroy(&tb);
701 return ret;
702}
703
704enum {
705 Opt_err,
706 Opt_new, Opt_load, Opt_update,
707 Opt_keyhandle, Opt_keyauth, Opt_blobauth,
708 Opt_pcrinfo, Opt_pcrlock, Opt_migratable,
709 Opt_hash,
710 Opt_policydigest,
711 Opt_policyhandle,
712};
713
714static const match_table_t key_tokens = {
715 {Opt_new, "new"},
716 {Opt_load, "load"},
717 {Opt_update, "update"},
718 {Opt_keyhandle, "keyhandle=%s"},
719 {Opt_keyauth, "keyauth=%s"},
720 {Opt_blobauth, "blobauth=%s"},
721 {Opt_pcrinfo, "pcrinfo=%s"},
722 {Opt_pcrlock, "pcrlock=%s"},
723 {Opt_migratable, "migratable=%s"},
724 {Opt_hash, "hash=%s"},
725 {Opt_policydigest, "policydigest=%s"},
726 {Opt_policyhandle, "policyhandle=%s"},
727 {Opt_err, NULL}
728};
729
730/* can have zero or more token= options */
731static int getoptions(char *c, struct trusted_key_payload *pay,
732 struct trusted_key_options *opt)
733{
734 substring_t args[MAX_OPT_ARGS];
735 char *p = c;
736 int token;
737 int res;
738 unsigned long handle;
739 unsigned long lock;
740 unsigned long token_mask = 0;
741 unsigned int digest_len;
742 int i;
743 int tpm2;
744
745 tpm2 = tpm_is_tpm2(chip);
746 if (tpm2 < 0)
747 return tpm2;
748
749 opt->hash = tpm2 ? HASH_ALGO_SHA256 : HASH_ALGO_SHA1;
750
751 while ((p = strsep(&c, " \t"))) {
752 if (*p == '\0' || *p == ' ' || *p == '\t')
753 continue;
754 token = match_token(p, key_tokens, args);
755 if (test_and_set_bit(token, &token_mask))
756 return -EINVAL;
757
758 switch (token) {
759 case Opt_pcrinfo:
760 opt->pcrinfo_len = strlen(args[0].from) / 2;
761 if (opt->pcrinfo_len > MAX_PCRINFO_SIZE)
762 return -EINVAL;
763 res = hex2bin(opt->pcrinfo, args[0].from,
764 opt->pcrinfo_len);
765 if (res < 0)
766 return -EINVAL;
767 break;
768 case Opt_keyhandle:
769 res = kstrtoul(args[0].from, 16, &handle);
770 if (res < 0)
771 return -EINVAL;
772 opt->keytype = SEAL_keytype;
773 opt->keyhandle = handle;
774 break;
775 case Opt_keyauth:
776 if (strlen(args[0].from) != 2 * SHA1_DIGEST_SIZE)
777 return -EINVAL;
778 res = hex2bin(opt->keyauth, args[0].from,
779 SHA1_DIGEST_SIZE);
780 if (res < 0)
781 return -EINVAL;
782 break;
783 case Opt_blobauth:
784 if (strlen(args[0].from) != 2 * SHA1_DIGEST_SIZE)
785 return -EINVAL;
786 res = hex2bin(opt->blobauth, args[0].from,
787 SHA1_DIGEST_SIZE);
788 if (res < 0)
789 return -EINVAL;
790 break;
791 case Opt_migratable:
792 if (*args[0].from == '0')
793 pay->migratable = 0;
794 else
795 return -EINVAL;
796 break;
797 case Opt_pcrlock:
798 res = kstrtoul(args[0].from, 10, &lock);
799 if (res < 0)
800 return -EINVAL;
801 opt->pcrlock = lock;
802 break;
803 case Opt_hash:
804 if (test_bit(Opt_policydigest, &token_mask))
805 return -EINVAL;
806 for (i = 0; i < HASH_ALGO__LAST; i++) {
807 if (!strcmp(args[0].from, hash_algo_name[i])) {
808 opt->hash = i;
809 break;
810 }
811 }
812 if (i == HASH_ALGO__LAST)
813 return -EINVAL;
814 if (!tpm2 && i != HASH_ALGO_SHA1) {
815 pr_info("trusted_key: TPM 1.x only supports SHA-1.\n");
816 return -EINVAL;
817 }
818 break;
819 case Opt_policydigest:
820 digest_len = hash_digest_size[opt->hash];
821 if (!tpm2 || strlen(args[0].from) != (2 * digest_len))
822 return -EINVAL;
823 res = hex2bin(opt->policydigest, args[0].from,
824 digest_len);
825 if (res < 0)
826 return -EINVAL;
827 opt->policydigest_len = digest_len;
828 break;
829 case Opt_policyhandle:
830 if (!tpm2)
831 return -EINVAL;
832 res = kstrtoul(args[0].from, 16, &handle);
833 if (res < 0)
834 return -EINVAL;
835 opt->policyhandle = handle;
836 break;
837 default:
838 return -EINVAL;
839 }
840 }
841 return 0;
842}
843
844/*
845 * datablob_parse - parse the keyctl data and fill in the
846 * payload and options structures
847 *
848 * On success returns 0, otherwise -EINVAL.
849 */
850static int datablob_parse(char *datablob, struct trusted_key_payload *p,
851 struct trusted_key_options *o)
852{
853 substring_t args[MAX_OPT_ARGS];
854 long keylen;
855 int ret = -EINVAL;
856 int key_cmd;
857 char *c;
858
859 /* main command */
860 c = strsep(&datablob, " \t");
861 if (!c)
862 return -EINVAL;
863 key_cmd = match_token(c, key_tokens, args);
864 switch (key_cmd) {
865 case Opt_new:
866 /* first argument is key size */
867 c = strsep(&datablob, " \t");
868 if (!c)
869 return -EINVAL;
870 ret = kstrtol(c, 10, &keylen);
871 if (ret < 0 || keylen < MIN_KEY_SIZE || keylen > MAX_KEY_SIZE)
872 return -EINVAL;
873 p->key_len = keylen;
874 ret = getoptions(datablob, p, o);
875 if (ret < 0)
876 return ret;
877 ret = Opt_new;
878 break;
879 case Opt_load:
880 /* first argument is sealed blob */
881 c = strsep(&datablob, " \t");
882 if (!c)
883 return -EINVAL;
884 p->blob_len = strlen(c) / 2;
885 if (p->blob_len > MAX_BLOB_SIZE)
886 return -EINVAL;
887 ret = hex2bin(p->blob, c, p->blob_len);
888 if (ret < 0)
889 return -EINVAL;
890 ret = getoptions(datablob, p, o);
891 if (ret < 0)
892 return ret;
893 ret = Opt_load;
894 break;
895 case Opt_update:
896 /* all arguments are options */
897 ret = getoptions(datablob, p, o);
898 if (ret < 0)
899 return ret;
900 ret = Opt_update;
901 break;
902 case Opt_err:
903 return -EINVAL;
904 break;
905 }
906 return ret;
907}
908
909static struct trusted_key_options *trusted_options_alloc(void)
910{
911 struct trusted_key_options *options;
912 int tpm2;
913
914 tpm2 = tpm_is_tpm2(chip);
915 if (tpm2 < 0)
916 return NULL;
917
918 options = kzalloc(sizeof *options, GFP_KERNEL);
919 if (options) {
920 /* set any non-zero defaults */
921 options->keytype = SRK_keytype;
922
923 if (!tpm2)
924 options->keyhandle = SRKHANDLE;
925 }
926 return options;
927}
928
929static struct trusted_key_payload *trusted_payload_alloc(struct key *key)
930{
931 struct trusted_key_payload *p = NULL;
932 int ret;
933
934 ret = key_payload_reserve(key, sizeof *p);
935 if (ret < 0)
936 return p;
937 p = kzalloc(sizeof *p, GFP_KERNEL);
938 if (p)
939 p->migratable = 1; /* migratable by default */
940 return p;
941}
942
943/*
944 * trusted_instantiate - create a new trusted key
945 *
946 * Unseal an existing trusted blob or, for a new key, get a
947 * random key, then seal and create a trusted key-type key,
948 * adding it to the specified keyring.
949 *
950 * On success, return 0. Otherwise return errno.
951 */
952static int trusted_instantiate(struct key *key,
953 struct key_preparsed_payload *prep)
954{
955 struct trusted_key_payload *payload = NULL;
956 struct trusted_key_options *options = NULL;
957 size_t datalen = prep->datalen;
958 char *datablob;
959 int ret = 0;
960 int key_cmd;
961 size_t key_len;
962 int tpm2;
963
964 tpm2 = tpm_is_tpm2(chip);
965 if (tpm2 < 0)
966 return tpm2;
967
968 if (datalen <= 0 || datalen > 32767 || !prep->data)
969 return -EINVAL;
970
971 datablob = kmalloc(datalen + 1, GFP_KERNEL);
972 if (!datablob)
973 return -ENOMEM;
974 memcpy(datablob, prep->data, datalen);
975 datablob[datalen] = '\0';
976
977 options = trusted_options_alloc();
978 if (!options) {
979 ret = -ENOMEM;
980 goto out;
981 }
982 payload = trusted_payload_alloc(key);
983 if (!payload) {
984 ret = -ENOMEM;
985 goto out;
986 }
987
988 key_cmd = datablob_parse(datablob, payload, options);
989 if (key_cmd < 0) {
990 ret = key_cmd;
991 goto out;
992 }
993
994 if (!options->keyhandle) {
995 ret = -EINVAL;
996 goto out;
997 }
998
999 dump_payload(payload);
1000 dump_options(options);
1001
1002 switch (key_cmd) {
1003 case Opt_load:
1004 if (tpm2)
1005 ret = tpm2_unseal_trusted(chip, payload, options);
1006 else
1007 ret = key_unseal(payload, options);
1008 dump_payload(payload);
1009 dump_options(options);
1010 if (ret < 0)
1011 pr_info("trusted_key: key_unseal failed (%d)\n", ret);
1012 break;
1013 case Opt_new:
1014 key_len = payload->key_len;
1015 ret = tpm_get_random(chip, payload->key, key_len);
1016 if (ret != key_len) {
1017 pr_info("trusted_key: key_create failed (%d)\n", ret);
1018 goto out;
1019 }
1020 if (tpm2)
1021 ret = tpm2_seal_trusted(chip, payload, options);
1022 else
1023 ret = key_seal(payload, options);
1024 if (ret < 0)
1025 pr_info("trusted_key: key_seal failed (%d)\n", ret);
1026 break;
1027 default:
1028 ret = -EINVAL;
1029 goto out;
1030 }
1031 if (!ret && options->pcrlock)
1032 ret = pcrlock(options->pcrlock);
1033out:
1034 kfree_sensitive(datablob);
1035 kfree_sensitive(options);
1036 if (!ret)
1037 rcu_assign_keypointer(key, payload);
1038 else
1039 kfree_sensitive(payload);
1040 return ret;
1041}
1042
1043static void trusted_rcu_free(struct rcu_head *rcu)
1044{
1045 struct trusted_key_payload *p;
1046
1047 p = container_of(rcu, struct trusted_key_payload, rcu);
1048 kfree_sensitive(p);
1049}
1050
1051/*
1052 * trusted_update - reseal an existing key with new PCR values
1053 */
1054static int trusted_update(struct key *key, struct key_preparsed_payload *prep)
1055{
1056 struct trusted_key_payload *p;
1057 struct trusted_key_payload *new_p;
1058 struct trusted_key_options *new_o;
1059 size_t datalen = prep->datalen;
1060 char *datablob;
1061 int ret = 0;
1062
1063 if (key_is_negative(key))
1064 return -ENOKEY;
1065 p = key->payload.data[0];
1066 if (!p->migratable)
1067 return -EPERM;
1068 if (datalen <= 0 || datalen > 32767 || !prep->data)
1069 return -EINVAL;
1070
1071 datablob = kmalloc(datalen + 1, GFP_KERNEL);
1072 if (!datablob)
1073 return -ENOMEM;
1074 new_o = trusted_options_alloc();
1075 if (!new_o) {
1076 ret = -ENOMEM;
1077 goto out;
1078 }
1079 new_p = trusted_payload_alloc(key);
1080 if (!new_p) {
1081 ret = -ENOMEM;
1082 goto out;
1083 }
1084
1085 memcpy(datablob, prep->data, datalen);
1086 datablob[datalen] = '\0';
1087 ret = datablob_parse(datablob, new_p, new_o);
1088 if (ret != Opt_update) {
1089 ret = -EINVAL;
1090 kfree_sensitive(new_p);
1091 goto out;
1092 }
1093
1094 if (!new_o->keyhandle) {
1095 ret = -EINVAL;
1096 kfree_sensitive(new_p);
1097 goto out;
1098 }
1099
1100 /* copy old key values, and reseal with new pcrs */
1101 new_p->migratable = p->migratable;
1102 new_p->key_len = p->key_len;
1103 memcpy(new_p->key, p->key, p->key_len);
1104 dump_payload(p);
1105 dump_payload(new_p);
1106
1107 ret = key_seal(new_p, new_o);
1108 if (ret < 0) {
1109 pr_info("trusted_key: key_seal failed (%d)\n", ret);
1110 kfree_sensitive(new_p);
1111 goto out;
1112 }
1113 if (new_o->pcrlock) {
1114 ret = pcrlock(new_o->pcrlock);
1115 if (ret < 0) {
1116 pr_info("trusted_key: pcrlock failed (%d)\n", ret);
1117 kfree_sensitive(new_p);
1118 goto out;
1119 }
1120 }
1121 rcu_assign_keypointer(key, new_p);
1122 call_rcu(&p->rcu, trusted_rcu_free);
1123out:
1124 kfree_sensitive(datablob);
1125 kfree_sensitive(new_o);
1126 return ret;
1127}
1128
1129/*
1130 * trusted_read - copy the sealed blob data to userspace in hex.
1131 * On success, return to userspace the trusted key datablob size.
1132 */
1133static long trusted_read(const struct key *key, char *buffer,
1134 size_t buflen)
1135{
1136 const struct trusted_key_payload *p;
1137 char *bufp;
1138 int i;
1139
1140 p = dereference_key_locked(key);
1141 if (!p)
1142 return -EINVAL;
1143
1144 if (buffer && buflen >= 2 * p->blob_len) {
1145 bufp = buffer;
1146 for (i = 0; i < p->blob_len; i++)
1147 bufp = hex_byte_pack(bufp, p->blob[i]);
1148 }
1149 return 2 * p->blob_len;
1150}
1151
1152/*
1153 * trusted_destroy - clear and free the key's payload
1154 */
1155static void trusted_destroy(struct key *key)
1156{
1157 kfree_sensitive(key->payload.data[0]);
1158}
1159
1160struct key_type key_type_trusted = {
1161 .name = "trusted",
1162 .instantiate = trusted_instantiate,
1163 .update = trusted_update,
1164 .destroy = trusted_destroy,
1165 .describe = user_describe,
1166 .read = trusted_read,
1167};
1168
1169EXPORT_SYMBOL_GPL(key_type_trusted);
1170
1171static void trusted_shash_release(void)
1172{
1173 if (hashalg)
1174 crypto_free_shash(hashalg);
1175 if (hmacalg)
1176 crypto_free_shash(hmacalg);
1177}
1178
1179static int __init trusted_shash_alloc(void)
1180{
1181 int ret;
1182
1183 hmacalg = crypto_alloc_shash(hmac_alg, 0, 0);
1184 if (IS_ERR(hmacalg)) {
1185 pr_info("trusted_key: could not allocate crypto %s\n",
1186 hmac_alg);
1187 return PTR_ERR(hmacalg);
1188 }
1189
1190 hashalg = crypto_alloc_shash(hash_alg, 0, 0);
1191 if (IS_ERR(hashalg)) {
1192 pr_info("trusted_key: could not allocate crypto %s\n",
1193 hash_alg);
1194 ret = PTR_ERR(hashalg);
1195 goto hashalg_fail;
1196 }
1197
1198 return 0;
1199
1200hashalg_fail:
1201 crypto_free_shash(hmacalg);
1202 return ret;
1203}
1204
1205static int __init init_digests(void)
1206{
1207 int i;
1208
1209 digests = kcalloc(chip->nr_allocated_banks, sizeof(*digests),
1210 GFP_KERNEL);
1211 if (!digests)
1212 return -ENOMEM;
1213
1214 for (i = 0; i < chip->nr_allocated_banks; i++)
1215 digests[i].alg_id = chip->allocated_banks[i].alg_id;
1216
1217 return 0;
1218}
1219
1220static int __init init_trusted(void)
1221{
1222 int ret;
1223
1224 /* encrypted_keys.ko depends on successful load of this module even if
1225 * TPM is not used.
1226 */
1227 chip = tpm_default_chip();
1228 if (!chip)
1229 return 0;
1230
1231 ret = init_digests();
1232 if (ret < 0)
1233 goto err_put;
1234 ret = trusted_shash_alloc();
1235 if (ret < 0)
1236 goto err_free;
1237 ret = register_key_type(&key_type_trusted);
1238 if (ret < 0)
1239 goto err_release;
1240 return 0;
1241err_release:
1242 trusted_shash_release();
1243err_free:
1244 kfree(digests);
1245err_put:
1246 put_device(&chip->dev);
1247 return ret;
1248}
1249
1250static void __exit cleanup_trusted(void)
1251{
1252 if (chip) {
1253 put_device(&chip->dev);
1254 kfree(digests);
1255 trusted_shash_release();
1256 unregister_key_type(&key_type_trusted);
1257 }
1258}
1259
1260late_initcall(init_trusted);
1261module_exit(cleanup_trusted);
1262
1263MODULE_LICENSE("GPL");