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[deliverable/linux.git] / security / keys / trusted_defined.c
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d00a1c72
MZ		 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/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>
93ae86e7 20#include <linux/err.h>
d00a1c72
MZ		 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_defined.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, const 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 const 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 return -EINVAL;
106 ret = crypto_shash_update(&sdesc->shash, data, dlen);
107 if (ret < 0)
108 goto out;
109 }
110 va_end(argp);
111 ret = crypto_shash_final(&sdesc->shash, digest);
112out:
113 kfree(sdesc);
114 return ret;
115}
116
117/*
118 * calculate authorization info fields to send to TPM
119 */
120static uint32_t TSS_authhmac(unsigned char *digest, const unsigned char *key,
121 const unsigned int keylen, unsigned char *h1,
122 unsigned char *h2, unsigned char h3, ...)
123{
124 unsigned char paramdigest[SHA1_DIGEST_SIZE];
125 struct sdesc *sdesc;
126 unsigned int dlen;
127 unsigned char *data;
128 unsigned char c;
129 int ret;
130 va_list argp;
131
132 sdesc = init_sdesc(hashalg);
133 if (IS_ERR(sdesc)) {
134 pr_info("trusted_key: can't alloc %s\n", hash_alg);
135 return PTR_ERR(sdesc);
136 }
137
138 c = h3;
139 ret = crypto_shash_init(&sdesc->shash);
140 if (ret < 0)
141 goto out;
142 va_start(argp, h3);
143 for (;;) {
144 dlen = va_arg(argp, unsigned int);
145 if (dlen == 0)
146 break;
147 data = va_arg(argp, unsigned char *);
148 ret = crypto_shash_update(&sdesc->shash, data, dlen);
149 if (ret < 0)
150 goto out;
151 }
152 va_end(argp);
153 ret = crypto_shash_final(&sdesc->shash, paramdigest);
154 if (!ret)
155 TSS_rawhmac(digest, key, keylen, SHA1_DIGEST_SIZE,
156 paramdigest, TPM_NONCE_SIZE, h1,
157 TPM_NONCE_SIZE, h2, 1, &c, 0, 0);
158out:
159 kfree(sdesc);
160 return ret;
161}
162
163/*
164 * verify the AUTH1_COMMAND (Seal) result from TPM
165 */
166static uint32_t TSS_checkhmac1(unsigned char *buffer,
167 const uint32_t command,
168 const unsigned char *ononce,
169 const unsigned char *key,
170 const unsigned int keylen, ...)
171{
172 uint32_t bufsize;
173 uint16_t tag;
174 uint32_t ordinal;
175 uint32_t result;
176 unsigned char *enonce;
177 unsigned char *continueflag;
178 unsigned char *authdata;
179 unsigned char testhmac[SHA1_DIGEST_SIZE];
180 unsigned char paramdigest[SHA1_DIGEST_SIZE];
181 struct sdesc *sdesc;
182 unsigned int dlen;
183 unsigned int dpos;
184 va_list argp;
185 int ret;
186
187 bufsize = LOAD32(buffer, TPM_SIZE_OFFSET);
188 tag = LOAD16(buffer, 0);
189 ordinal = command;
190 result = LOAD32N(buffer, TPM_RETURN_OFFSET);
191 if (tag == TPM_TAG_RSP_COMMAND)
192 return 0;
193 if (tag != TPM_TAG_RSP_AUTH1_COMMAND)
194 return -EINVAL;
195 authdata = buffer + bufsize - SHA1_DIGEST_SIZE;
196 continueflag = authdata - 1;
197 enonce = continueflag - TPM_NONCE_SIZE;
198
199 sdesc = init_sdesc(hashalg);
200 if (IS_ERR(sdesc)) {
201 pr_info("trusted_key: can't alloc %s\n", hash_alg);
202 return PTR_ERR(sdesc);
203 }
204 ret = crypto_shash_init(&sdesc->shash);
205 if (ret < 0)
206 goto out;
207 ret = crypto_shash_update(&sdesc->shash, (const u8 *)&result,
208 sizeof result);
209 if (ret < 0)
210 goto out;
211 ret = crypto_shash_update(&sdesc->shash, (const u8 *)&ordinal,
212 sizeof ordinal);
213 if (ret < 0)
214 goto out;
215 va_start(argp, keylen);
216 for (;;) {
217 dlen = va_arg(argp, unsigned int);
218 if (dlen == 0)
219 break;
220 dpos = va_arg(argp, unsigned int);
221 ret = crypto_shash_update(&sdesc->shash, buffer + dpos, dlen);
222 if (ret < 0)
223 goto out;
224 }
225 va_end(argp);
226 ret = crypto_shash_final(&sdesc->shash, paramdigest);
227 if (ret < 0)
228 goto out;
229 ret = TSS_rawhmac(testhmac, key, keylen, SHA1_DIGEST_SIZE, paramdigest,
230 TPM_NONCE_SIZE, enonce, TPM_NONCE_SIZE, ononce,
231 1, continueflag, 0, 0);
232 if (ret < 0)
233 goto out;
234 if (memcmp(testhmac, authdata, SHA1_DIGEST_SIZE))
235 ret = -EINVAL;
236out:
237 kfree(sdesc);
238 return ret;
239}
240
241/*
242 * verify the AUTH2_COMMAND (unseal) result from TPM
243 */
244static uint32_t TSS_checkhmac2(unsigned char *buffer,
245 const uint32_t command,
246 const unsigned char *ononce,
247 const unsigned char *key1,
248 const unsigned int keylen1,
249 const unsigned char *key2,
250 const unsigned int keylen2, ...)
251{
252 uint32_t bufsize;
253 uint16_t tag;
254 uint32_t ordinal;
255 uint32_t result;
256 unsigned char *enonce1;
257 unsigned char *continueflag1;
258 unsigned char *authdata1;
259 unsigned char *enonce2;
260 unsigned char *continueflag2;
261 unsigned char *authdata2;
262 unsigned char testhmac1[SHA1_DIGEST_SIZE];
263 unsigned char testhmac2[SHA1_DIGEST_SIZE];
264 unsigned char paramdigest[SHA1_DIGEST_SIZE];
265 struct sdesc *sdesc;
266 unsigned int dlen;
267 unsigned int dpos;
268 va_list argp;
269 int ret;
270
271 bufsize = LOAD32(buffer, TPM_SIZE_OFFSET);
272 tag = LOAD16(buffer, 0);
273 ordinal = command;
274 result = LOAD32N(buffer, TPM_RETURN_OFFSET);
275
276 if (tag == TPM_TAG_RSP_COMMAND)
277 return 0;
278 if (tag != TPM_TAG_RSP_AUTH2_COMMAND)
279 return -EINVAL;
280 authdata1 = buffer + bufsize - (SHA1_DIGEST_SIZE + 1
281 + SHA1_DIGEST_SIZE + SHA1_DIGEST_SIZE);
282 authdata2 = buffer + bufsize - (SHA1_DIGEST_SIZE);
283 continueflag1 = authdata1 - 1;
284 continueflag2 = authdata2 - 1;
285 enonce1 = continueflag1 - TPM_NONCE_SIZE;
286 enonce2 = continueflag2 - TPM_NONCE_SIZE;
287
288 sdesc = init_sdesc(hashalg);
289 if (IS_ERR(sdesc)) {
290 pr_info("trusted_key: can't alloc %s\n", hash_alg);
291 return PTR_ERR(sdesc);
292 }
293 ret = crypto_shash_init(&sdesc->shash);
294 if (ret < 0)
295 goto out;
296 ret = crypto_shash_update(&sdesc->shash, (const u8 *)&result,
297 sizeof result);
298 if (ret < 0)
299 goto out;
300 ret = crypto_shash_update(&sdesc->shash, (const u8 *)&ordinal,
301 sizeof ordinal);
302 if (ret < 0)
303 goto out;
304
305 va_start(argp, keylen2);
306 for (;;) {
307 dlen = va_arg(argp, unsigned int);
308 if (dlen == 0)
309 break;
310 dpos = va_arg(argp, unsigned int);
311 ret = crypto_shash_update(&sdesc->shash, buffer + dpos, dlen);
312 if (ret < 0)
313 goto out;
314 }
315 ret = crypto_shash_final(&sdesc->shash, paramdigest);
316 if (ret < 0)
317 goto out;
318
319 ret = TSS_rawhmac(testhmac1, key1, keylen1, SHA1_DIGEST_SIZE,
320 paramdigest, TPM_NONCE_SIZE, enonce1,
321 TPM_NONCE_SIZE, ononce, 1, continueflag1, 0, 0);
322 if (memcmp(testhmac1, authdata1, SHA1_DIGEST_SIZE)) {
323 ret = -EINVAL;
324 goto out;
325 }
326 ret = TSS_rawhmac(testhmac2, key2, keylen2, SHA1_DIGEST_SIZE,
327 paramdigest, TPM_NONCE_SIZE, enonce2,
328 TPM_NONCE_SIZE, ononce, 1, continueflag2, 0, 0);
329 if (memcmp(testhmac2, authdata2, SHA1_DIGEST_SIZE))
330 ret = -EINVAL;
331out:
332 kfree(sdesc);
333 return ret;
334}
335
336/*
337 * For key specific tpm requests, we will generate and send our
338 * own TPM command packets using the drivers send function.
339 */
340static int trusted_tpm_send(const u32 chip_num, unsigned char *cmd,
341 size_t buflen)
342{
343 int rc;
344
345 dump_tpm_buf(cmd);
346 rc = tpm_send(chip_num, cmd, buflen);
347 dump_tpm_buf(cmd);
348 if (rc > 0)
349 /* Can't return positive return codes values to keyctl */
350 rc = -EPERM;
351 return rc;
352}
353
354/*
355 * get a random value from TPM
356 */
357static int tpm_get_random(struct tpm_buf *tb, unsigned char *buf, uint32_t len)
358{
359 int ret;
360
361 INIT_BUF(tb);
362 store16(tb, TPM_TAG_RQU_COMMAND);
363 store32(tb, TPM_GETRANDOM_SIZE);
364 store32(tb, TPM_ORD_GETRANDOM);
365 store32(tb, len);
366 ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, sizeof tb->data);
367 memcpy(buf, tb->data + TPM_GETRANDOM_SIZE, len);
368
369 return ret;
370}
371
372static int my_get_random(unsigned char *buf, int len)
373{
374 struct tpm_buf *tb;
375 int ret;
376
377 tb = kzalloc(sizeof *tb, GFP_KERNEL);
378 if (!tb)
379 return -ENOMEM;
380 ret = tpm_get_random(tb, buf, len);
381
382 kfree(tb);
383 return ret;
384}
385
386/*
387 * Lock a trusted key, by extending a selected PCR.
388 *
389 * Prevents a trusted key that is sealed to PCRs from being accessed.
390 * This uses the tpm driver's extend function.
391 */
392static int pcrlock(const int pcrnum)
393{
394 unsigned char hash[SHA1_DIGEST_SIZE];
395
396 if (!capable(CAP_SYS_ADMIN))
397 return -EPERM;
398 my_get_random(hash, SHA1_DIGEST_SIZE);
399 return tpm_pcr_extend(TPM_ANY_NUM, pcrnum, hash) ? -EINVAL : 0;
400}
401
402/*
403 * Create an object specific authorisation protocol (OSAP) session
404 */
405static int osap(struct tpm_buf *tb, struct osapsess *s,
406 const unsigned char *key, const uint16_t type,
407 const uint32_t handle)
408{
409 unsigned char enonce[TPM_NONCE_SIZE];
410 unsigned char ononce[TPM_NONCE_SIZE];
411 int ret;
412
413 ret = tpm_get_random(tb, ononce, TPM_NONCE_SIZE);
414 if (ret < 0)
415 return ret;
416
417 INIT_BUF(tb);
418 store16(tb, TPM_TAG_RQU_COMMAND);
419 store32(tb, TPM_OSAP_SIZE);
420 store32(tb, TPM_ORD_OSAP);
421 store16(tb, type);
422 store32(tb, handle);
423 storebytes(tb, ononce, TPM_NONCE_SIZE);
424
425 ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE);
426 if (ret < 0)
427 return ret;
428
429 s->handle = LOAD32(tb->data, TPM_DATA_OFFSET);
430 memcpy(s->enonce, &(tb->data[TPM_DATA_OFFSET + sizeof(uint32_t)]),
431 TPM_NONCE_SIZE);
432 memcpy(enonce, &(tb->data[TPM_DATA_OFFSET + sizeof(uint32_t) +
433 TPM_NONCE_SIZE]), TPM_NONCE_SIZE);
434 ret = TSS_rawhmac(s->secret, key, SHA1_DIGEST_SIZE, TPM_NONCE_SIZE,
435 enonce, TPM_NONCE_SIZE, ononce, 0, 0);
436 return ret;
437}
438
439/*
440 * Create an object independent authorisation protocol (oiap) session
441 */
442static int oiap(struct tpm_buf *tb, uint32_t *handle, unsigned char *nonce)
443{
444 int ret;
445
446 INIT_BUF(tb);
447 store16(tb, TPM_TAG_RQU_COMMAND);
448 store32(tb, TPM_OIAP_SIZE);
449 store32(tb, TPM_ORD_OIAP);
450 ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE);
451 if (ret < 0)
452 return ret;
453
454 *handle = LOAD32(tb->data, TPM_DATA_OFFSET);
455 memcpy(nonce, &tb->data[TPM_DATA_OFFSET + sizeof(uint32_t)],
456 TPM_NONCE_SIZE);
457 return ret;
458}
459
460struct tpm_digests {
461 unsigned char encauth[SHA1_DIGEST_SIZE];
462 unsigned char pubauth[SHA1_DIGEST_SIZE];
463 unsigned char xorwork[SHA1_DIGEST_SIZE * 2];
464 unsigned char xorhash[SHA1_DIGEST_SIZE];
465 unsigned char nonceodd[TPM_NONCE_SIZE];
466};
467
468/*
469 * Have the TPM seal(encrypt) the trusted key, possibly based on
470 * Platform Configuration Registers (PCRs). AUTH1 for sealing key.
471 */
472static int tpm_seal(struct tpm_buf *tb, const uint16_t keytype,
473 const uint32_t keyhandle, const unsigned char *keyauth,
474 const unsigned char *data, const uint32_t datalen,
475 unsigned char *blob, uint32_t *bloblen,
476 const unsigned char *blobauth,
477 const unsigned char *pcrinfo, const uint32_t pcrinfosize)
478{
479 struct osapsess sess;
480 struct tpm_digests *td;
481 unsigned char cont;
482 uint32_t ordinal;
483 uint32_t pcrsize;
484 uint32_t datsize;
485 int sealinfosize;
486 int encdatasize;
487 int storedsize;
488 int ret;
489 int i;
490
491 /* alloc some work space for all the hashes */
492 td = kmalloc(sizeof *td, GFP_KERNEL);
493 if (!td)
494 return -ENOMEM;
495
496 /* get session for sealing key */
497 ret = osap(tb, &sess, keyauth, keytype, keyhandle);
498 if (ret < 0)
499 return ret;
500 dump_sess(&sess);
501
502 /* calculate encrypted authorization value */
503 memcpy(td->xorwork, sess.secret, SHA1_DIGEST_SIZE);
504 memcpy(td->xorwork + SHA1_DIGEST_SIZE, sess.enonce, SHA1_DIGEST_SIZE);
505 ret = TSS_sha1(td->xorwork, SHA1_DIGEST_SIZE * 2, td->xorhash);
506 if (ret < 0)
507 return ret;
508
509 ret = tpm_get_random(tb, td->nonceodd, TPM_NONCE_SIZE);
510 if (ret < 0)
511 return ret;
512 ordinal = htonl(TPM_ORD_SEAL);
513 datsize = htonl(datalen);
514 pcrsize = htonl(pcrinfosize);
515 cont = 0;
516
517 /* encrypt data authorization key */
518 for (i = 0; i < SHA1_DIGEST_SIZE; ++i)
519 td->encauth[i] = td->xorhash[i] ^ blobauth[i];
520
521 /* calculate authorization HMAC value */
522 if (pcrinfosize == 0) {
523 /* no pcr info specified */
524 TSS_authhmac(td->pubauth, sess.secret, SHA1_DIGEST_SIZE,
525 sess.enonce, td->nonceodd, cont, sizeof(uint32_t),
526 &ordinal, SHA1_DIGEST_SIZE, td->encauth,
527 sizeof(uint32_t), &pcrsize, sizeof(uint32_t),
528 &datsize, datalen, data, 0, 0);
529 } else {
530 /* pcr info specified */
531 TSS_authhmac(td->pubauth, sess.secret, SHA1_DIGEST_SIZE,
532 sess.enonce, td->nonceodd, cont, sizeof(uint32_t),
533 &ordinal, SHA1_DIGEST_SIZE, td->encauth,
534 sizeof(uint32_t), &pcrsize, pcrinfosize,
535 pcrinfo, sizeof(uint32_t), &datsize, datalen,
536 data, 0, 0);
537 }
538
539 /* build and send the TPM request packet */
540 INIT_BUF(tb);
541 store16(tb, TPM_TAG_RQU_AUTH1_COMMAND);
542 store32(tb, TPM_SEAL_SIZE + pcrinfosize + datalen);
543 store32(tb, TPM_ORD_SEAL);
544 store32(tb, keyhandle);
545 storebytes(tb, td->encauth, SHA1_DIGEST_SIZE);
546 store32(tb, pcrinfosize);
547 storebytes(tb, pcrinfo, pcrinfosize);
548 store32(tb, datalen);
549 storebytes(tb, data, datalen);
550 store32(tb, sess.handle);
551 storebytes(tb, td->nonceodd, TPM_NONCE_SIZE);
552 store8(tb, cont);
553 storebytes(tb, td->pubauth, SHA1_DIGEST_SIZE);
554
555 ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE);
556 if (ret < 0)
557 return ret;
558
559 /* calculate the size of the returned Blob */
560 sealinfosize = LOAD32(tb->data, TPM_DATA_OFFSET + sizeof(uint32_t));
561 encdatasize = LOAD32(tb->data, TPM_DATA_OFFSET + sizeof(uint32_t) +
562 sizeof(uint32_t) + sealinfosize);
563 storedsize = sizeof(uint32_t) + sizeof(uint32_t) + sealinfosize +
564 sizeof(uint32_t) + encdatasize;
565
566 /* check the HMAC in the response */
567 ret = TSS_checkhmac1(tb->data, ordinal, td->nonceodd, sess.secret,
568 SHA1_DIGEST_SIZE, storedsize, TPM_DATA_OFFSET, 0,
569 0);
570
571 /* copy the returned blob to caller */
572 memcpy(blob, tb->data + TPM_DATA_OFFSET, storedsize);
573 *bloblen = storedsize;
574 return ret;
575}
576
577/*
578 * use the AUTH2_COMMAND form of unseal, to authorize both key and blob
579 */
580static int tpm_unseal(struct tpm_buf *tb,
581 const uint32_t keyhandle, const unsigned char *keyauth,
582 const unsigned char *blob, const int bloblen,
583 const unsigned char *blobauth,
584 unsigned char *data, unsigned int *datalen)
585{
586 unsigned char nonceodd[TPM_NONCE_SIZE];
587 unsigned char enonce1[TPM_NONCE_SIZE];
588 unsigned char enonce2[TPM_NONCE_SIZE];
589 unsigned char authdata1[SHA1_DIGEST_SIZE];
590 unsigned char authdata2[SHA1_DIGEST_SIZE];
591 uint32_t authhandle1 = 0;
592 uint32_t authhandle2 = 0;
593 unsigned char cont = 0;
594 uint32_t ordinal;
595 uint32_t keyhndl;
596 int ret;
597
598 /* sessions for unsealing key and data */
599 ret = oiap(tb, &authhandle1, enonce1);
600 if (ret < 0) {
601 pr_info("trusted_key: oiap failed (%d)\n", ret);
602 return ret;
603 }
604 ret = oiap(tb, &authhandle2, enonce2);
605 if (ret < 0) {
606 pr_info("trusted_key: oiap failed (%d)\n", ret);
607 return ret;
608 }
609
610 ordinal = htonl(TPM_ORD_UNSEAL);
611 keyhndl = htonl(SRKHANDLE);
612 ret = tpm_get_random(tb, nonceodd, TPM_NONCE_SIZE);
613 if (ret < 0) {
614 pr_info("trusted_key: tpm_get_random failed (%d)\n", ret);
615 return ret;
616 }
617 TSS_authhmac(authdata1, keyauth, TPM_NONCE_SIZE,
618 enonce1, nonceodd, cont, sizeof(uint32_t),
619 &ordinal, bloblen, blob, 0, 0);
620 TSS_authhmac(authdata2, blobauth, TPM_NONCE_SIZE,
621 enonce2, nonceodd, cont, sizeof(uint32_t),
622 &ordinal, bloblen, blob, 0, 0);
623
624 /* build and send TPM request packet */
625 INIT_BUF(tb);
626 store16(tb, TPM_TAG_RQU_AUTH2_COMMAND);
627 store32(tb, TPM_UNSEAL_SIZE + bloblen);
628 store32(tb, TPM_ORD_UNSEAL);
629 store32(tb, keyhandle);
630 storebytes(tb, blob, bloblen);
631 store32(tb, authhandle1);
632 storebytes(tb, nonceodd, TPM_NONCE_SIZE);
633 store8(tb, cont);
634 storebytes(tb, authdata1, SHA1_DIGEST_SIZE);
635 store32(tb, authhandle2);
636 storebytes(tb, nonceodd, TPM_NONCE_SIZE);
637 store8(tb, cont);
638 storebytes(tb, authdata2, SHA1_DIGEST_SIZE);
639
640 ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE);
641 if (ret < 0) {
642 pr_info("trusted_key: authhmac failed (%d)\n", ret);
643 return ret;
644 }
645
646 *datalen = LOAD32(tb->data, TPM_DATA_OFFSET);
647 ret = TSS_checkhmac2(tb->data, ordinal, nonceodd,
648 keyauth, SHA1_DIGEST_SIZE,
649 blobauth, SHA1_DIGEST_SIZE,
650 sizeof(uint32_t), TPM_DATA_OFFSET,
651 *datalen, TPM_DATA_OFFSET + sizeof(uint32_t), 0,
652 0);
653 if (ret < 0)
654 pr_info("trusted_key: TSS_checkhmac2 failed (%d)\n", ret);
655 memcpy(data, tb->data + TPM_DATA_OFFSET + sizeof(uint32_t), *datalen);
656 return ret;
657}
658
659/*
660 * Have the TPM seal(encrypt) the symmetric key
661 */
662static int key_seal(struct trusted_key_payload *p,
663 struct trusted_key_options *o)
664{
665 struct tpm_buf *tb;
666 int ret;
667
668 tb = kzalloc(sizeof *tb, GFP_KERNEL);
669 if (!tb)
670 return -ENOMEM;
671
672 /* include migratable flag at end of sealed key */
673 p->key[p->key_len] = p->migratable;
674
675 ret = tpm_seal(tb, o->keytype, o->keyhandle, o->keyauth,
676 p->key, p->key_len + 1, p->blob, &p->blob_len,
677 o->blobauth, o->pcrinfo, o->pcrinfo_len);
678 if (ret < 0)
679 pr_info("trusted_key: srkseal failed (%d)\n", ret);
680
681 kfree(tb);
682 return ret;
683}
684
685/*
686 * Have the TPM unseal(decrypt) the symmetric key
687 */
688static int key_unseal(struct trusted_key_payload *p,
689 struct trusted_key_options *o)
690{
691 struct tpm_buf *tb;
692 int ret;
693
694 tb = kzalloc(sizeof *tb, GFP_KERNEL);
695 if (!tb)
696 return -ENOMEM;
697
698 ret = tpm_unseal(tb, o->keyhandle, o->keyauth, p->blob, p->blob_len,
699 o->blobauth, p->key, &p->key_len);
700 /* pull migratable flag out of sealed key */
701 p->migratable = p->key[--p->key_len];
702
703 if (ret < 0)
704 pr_info("trusted_key: srkunseal failed (%d)\n", ret);
705
706 kfree(tb);
707 return ret;
708}
709
710enum {
711 Opt_err = -1,
712 Opt_new, Opt_load, Opt_update,
713 Opt_keyhandle, Opt_keyauth, Opt_blobauth,
714 Opt_pcrinfo, Opt_pcrlock, Opt_migratable
715};
716
717static const match_table_t key_tokens = {
718 {Opt_new, "new"},
719 {Opt_load, "load"},
720 {Opt_update, "update"},
721 {Opt_keyhandle, "keyhandle=%s"},
722 {Opt_keyauth, "keyauth=%s"},
723 {Opt_blobauth, "blobauth=%s"},
724 {Opt_pcrinfo, "pcrinfo=%s"},
725 {Opt_pcrlock, "pcrlock=%s"},
726 {Opt_migratable, "migratable=%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
741 while ((p = strsep(&c, " \t"))) {
742 if (*p == '\0' || *p == ' ' || *p == '\t')
743 continue;
744 token = match_token(p, key_tokens, args);
745
746 switch (token) {
747 case Opt_pcrinfo:
748 opt->pcrinfo_len = strlen(args[0].from) / 2;
749 if (opt->pcrinfo_len > MAX_PCRINFO_SIZE)
750 return -EINVAL;
751 hex2bin(opt->pcrinfo, args[0].from, opt->pcrinfo_len);
752 break;
753 case Opt_keyhandle:
754 res = strict_strtoul(args[0].from, 16, &handle);
755 if (res < 0)
756 return -EINVAL;
757 opt->keytype = SEAL_keytype;
758 opt->keyhandle = handle;
759 break;
760 case Opt_keyauth:
761 if (strlen(args[0].from) != 2 * SHA1_DIGEST_SIZE)
762 return -EINVAL;
763 hex2bin(opt->keyauth, args[0].from, SHA1_DIGEST_SIZE);
764 break;
765 case Opt_blobauth:
766 if (strlen(args[0].from) != 2 * SHA1_DIGEST_SIZE)
767 return -EINVAL;
768 hex2bin(opt->blobauth, args[0].from, SHA1_DIGEST_SIZE);
769 break;
770 case Opt_migratable:
771 if (*args[0].from == '0')
772 pay->migratable = 0;
773 else
774 return -EINVAL;
775 break;
776 case Opt_pcrlock:
777 res = strict_strtoul(args[0].from, 10, &lock);
778 if (res < 0)
779 return -EINVAL;
780 opt->pcrlock = lock;
781 break;
782 default:
783 return -EINVAL;
784 }
785 }
786 return 0;
787}
788
789/*
790 * datablob_parse - parse the keyctl data and fill in the
791 * payload and options structures
792 *
793 * On success returns 0, otherwise -EINVAL.
794 */
795static int datablob_parse(char *datablob, struct trusted_key_payload *p,
796 struct trusted_key_options *o)
797{
798 substring_t args[MAX_OPT_ARGS];
799 long keylen;
800 int ret = -EINVAL;
801 int key_cmd;
802 char *c;
803
804 /* main command */
805 c = strsep(&datablob, " \t");
806 if (!c)
807 return -EINVAL;
808 key_cmd = match_token(c, key_tokens, args);
809 switch (key_cmd) {
810 case Opt_new:
811 /* first argument is key size */
812 c = strsep(&datablob, " \t");
813 if (!c)
814 return -EINVAL;
815 ret = strict_strtol(c, 10, &keylen);
816 if (ret < 0 || keylen < MIN_KEY_SIZE || keylen > MAX_KEY_SIZE)
817 return -EINVAL;
818 p->key_len = keylen;
819 ret = getoptions(datablob, p, o);
820 if (ret < 0)
821 return ret;
822 ret = Opt_new;
823 break;
824 case Opt_load:
825 /* first argument is sealed blob */
826 c = strsep(&datablob, " \t");
827 if (!c)
828 return -EINVAL;
829 p->blob_len = strlen(c) / 2;
830 if (p->blob_len > MAX_BLOB_SIZE)
831 return -EINVAL;
832 hex2bin(p->blob, c, p->blob_len);
833 ret = getoptions(datablob, p, o);
834 if (ret < 0)
835 return ret;
836 ret = Opt_load;
837 break;
838 case Opt_update:
839 /* all arguments are options */
840 ret = getoptions(datablob, p, o);
841 if (ret < 0)
842 return ret;
843 ret = Opt_update;
844 break;
845 case Opt_err:
846 return -EINVAL;
847 break;
848 }
849 return ret;
850}
851
852static struct trusted_key_options *trusted_options_alloc(void)
853{
854 struct trusted_key_options *options;
855
856 options = kzalloc(sizeof *options, GFP_KERNEL);
857 if (!options)
858 return options;
859
860 /* set any non-zero defaults */
861 options->keytype = SRK_keytype;
862 options->keyhandle = SRKHANDLE;
863 return options;
864}
865
866static struct trusted_key_payload *trusted_payload_alloc(struct key *key)
867{
868 struct trusted_key_payload *p = NULL;
869 int ret;
870
871 ret = key_payload_reserve(key, sizeof *p);
872 if (ret < 0)
873 return p;
874 p = kzalloc(sizeof *p, GFP_KERNEL);
875
876 /* migratable by default */
877 p->migratable = 1;
878 return p;
879}
880
881/*
882 * trusted_instantiate - create a new trusted key
883 *
884 * Unseal an existing trusted blob or, for a new key, get a
885 * random key, then seal and create a trusted key-type key,
886 * adding it to the specified keyring.
887 *
888 * On success, return 0. Otherwise return errno.
889 */
890static int trusted_instantiate(struct key *key, const void *data,
891 const size_t datalen)
892{
893 struct trusted_key_payload *payload = NULL;
894 struct trusted_key_options *options = NULL;
895 char *datablob;
896 int ret = 0;
897 int key_cmd;
898
899 if (datalen <= 0 || datalen > 32767 || !data)
900 return -EINVAL;
901
902 datablob = kmalloc(datalen + 1, GFP_KERNEL);
903 if (!datablob)
904 return -ENOMEM;
905 memcpy(datablob, data, datalen);
906 datablob[datalen] = '\0';
907
908 options = trusted_options_alloc();
909 if (!options) {
910 ret = -ENOMEM;
911 goto out;
912 }
913 payload = trusted_payload_alloc(key);
914 if (!payload) {
915 ret = -ENOMEM;
916 goto out;
917 }
918
919 key_cmd = datablob_parse(datablob, payload, options);
920 if (key_cmd < 0) {
921 ret = key_cmd;
922 goto out;
923 }
924
925 dump_payload(payload);
926 dump_options(options);
927
928 switch (key_cmd) {
929 case Opt_load:
930 ret = key_unseal(payload, options);
931 dump_payload(payload);
932 dump_options(options);
933 if (ret < 0)
934 pr_info("trusted_key: key_unseal failed (%d)\n", ret);
935 break;
936 case Opt_new:
937 ret = my_get_random(payload->key, payload->key_len);
938 if (ret < 0) {
939 pr_info("trusted_key: key_create failed (%d)\n", ret);
940 goto out;
941 }
942 ret = key_seal(payload, options);
943 if (ret < 0)
944 pr_info("trusted_key: key_seal failed (%d)\n", ret);
945 break;
946 default:
947 ret = -EINVAL;
948 goto out;
949 }
950 if (!ret && options->pcrlock)
951 ret = pcrlock(options->pcrlock);
952out:
953 kfree(datablob);
954 kfree(options);
955 if (!ret)
956 rcu_assign_pointer(key->payload.data, payload);
957 else
958 kfree(payload);
959 return ret;
960}
961
962static void trusted_rcu_free(struct rcu_head *rcu)
963{
964 struct trusted_key_payload *p;
965
966 p = container_of(rcu, struct trusted_key_payload, rcu);
967 memset(p->key, 0, p->key_len);
968 kfree(p);
969}
970
971/*
972 * trusted_update - reseal an existing key with new PCR values
973 */
974static int trusted_update(struct key *key, const void *data,
975 const size_t datalen)
976{
977 struct trusted_key_payload *p = key->payload.data;
978 struct trusted_key_payload *new_p;
979 struct trusted_key_options *new_o;
980 char *datablob;
981 int ret = 0;
982
983 if (!p->migratable)
984 return -EPERM;
985 if (datalen <= 0 || datalen > 32767 || !data)
986 return -EINVAL;
987
988 datablob = kmalloc(datalen + 1, GFP_KERNEL);
989 if (!datablob)
990 return -ENOMEM;
991 new_o = trusted_options_alloc();
992 if (!new_o) {
993 ret = -ENOMEM;
994 goto out;
995 }
996 new_p = trusted_payload_alloc(key);
997 if (!new_p) {
998 ret = -ENOMEM;
999 goto out;
1000 }
1001
1002 memcpy(datablob, data, datalen);
1003 datablob[datalen] = '\0';
1004 ret = datablob_parse(datablob, new_p, new_o);
1005 if (ret != Opt_update) {
1006 ret = -EINVAL;
1007 goto out;
1008 }
1009 /* copy old key values, and reseal with new pcrs */
1010 new_p->migratable = p->migratable;
1011 new_p->key_len = p->key_len;
1012 memcpy(new_p->key, p->key, p->key_len);
1013 dump_payload(p);
1014 dump_payload(new_p);
1015
1016 ret = key_seal(new_p, new_o);
1017 if (ret < 0) {
1018 pr_info("trusted_key: key_seal failed (%d)\n", ret);
1019 kfree(new_p);
1020 goto out;
1021 }
1022 if (new_o->pcrlock) {
1023 ret = pcrlock(new_o->pcrlock);
1024 if (ret < 0) {
1025 pr_info("trusted_key: pcrlock failed (%d)\n", ret);
1026 kfree(new_p);
1027 goto out;
1028 }
1029 }
1030 rcu_assign_pointer(key->payload.data, new_p);
1031 call_rcu(&p->rcu, trusted_rcu_free);
1032out:
1033 kfree(datablob);
1034 kfree(new_o);
1035 return ret;
1036}
1037
1038/*
1039 * trusted_read - copy the sealed blob data to userspace in hex.
1040 * On success, return to userspace the trusted key datablob size.
1041 */
1042static long trusted_read(const struct key *key, char __user *buffer,
1043 size_t buflen)
1044{
1045 struct trusted_key_payload *p;
1046 char *ascii_buf;
1047 char *bufp;
1048 int i;
1049
1050 p = rcu_dereference_protected(key->payload.data,
1051 rwsem_is_locked(&((struct key *)key)->sem));
1052 if (!p)
1053 return -EINVAL;
1054 if (!buffer || buflen <= 0)
1055 return 2 * p->blob_len;
1056 ascii_buf = kmalloc(2 * p->blob_len, GFP_KERNEL);
1057 if (!ascii_buf)
1058 return -ENOMEM;
1059
1060 bufp = ascii_buf;
1061 for (i = 0; i < p->blob_len; i++)
1062 bufp = pack_hex_byte(bufp, p->blob[i]);
1063 if ((copy_to_user(buffer, ascii_buf, 2 * p->blob_len)) != 0) {
1064 kfree(ascii_buf);
1065 return -EFAULT;
1066 }
1067 kfree(ascii_buf);
1068 return 2 * p->blob_len;
1069}
1070
1071/*
1072 * trusted_destroy - before freeing the key, clear the decrypted data
1073 */
1074static void trusted_destroy(struct key *key)
1075{
1076 struct trusted_key_payload *p = key->payload.data;
1077
1078 if (!p)
1079 return;
1080 memset(p->key, 0, p->key_len);
1081 kfree(key->payload.data);
1082}
1083
1084struct key_type key_type_trusted = {
1085 .name = "trusted",
1086 .instantiate = trusted_instantiate,
1087 .update = trusted_update,
1088 .match = user_match,
1089 .destroy = trusted_destroy,
1090 .describe = user_describe,
1091 .read = trusted_read,
1092};
1093
1094EXPORT_SYMBOL_GPL(key_type_trusted);
1095
1096static void trusted_shash_release(void)
1097{
1098 if (hashalg)
1099 crypto_free_shash(hashalg);
1100 if (hmacalg)
1101 crypto_free_shash(hmacalg);
1102}
1103
1104static int __init trusted_shash_alloc(void)
1105{
1106 int ret;
1107
1108 hmacalg = crypto_alloc_shash(hmac_alg, 0, CRYPTO_ALG_ASYNC);
1109 if (IS_ERR(hmacalg)) {
1110 pr_info("trusted_key: could not allocate crypto %s\n",
1111 hmac_alg);
1112 return PTR_ERR(hmacalg);
1113 }
1114
1115 hashalg = crypto_alloc_shash(hash_alg, 0, CRYPTO_ALG_ASYNC);
1116 if (IS_ERR(hashalg)) {
1117 pr_info("trusted_key: could not allocate crypto %s\n",
1118 hash_alg);
1119 ret = PTR_ERR(hashalg);
1120 goto hashalg_fail;
1121 }
1122
1123 return 0;
1124
1125hashalg_fail:
1126 crypto_free_shash(hmacalg);
1127 return ret;
1128}
1129
1130static int __init init_trusted(void)
1131{
1132 int ret;
1133
1134 ret = trusted_shash_alloc();
1135 if (ret < 0)
1136 return ret;
1137 ret = register_key_type(&key_type_trusted);
1138 if (ret < 0)
1139 trusted_shash_release();
1140 return ret;
1141}
1142
1143static void __exit cleanup_trusted(void)
1144{
1145 trusted_shash_release();
1146 unregister_key_type(&key_type_trusted);
1147}
1148
1149late_initcall(init_trusted);
1150module_exit(cleanup_trusted);
1151
1152MODULE_LICENSE("GPL");
Linux kernel - Deliverables
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