1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * Copyright (C) 2010 IBM Corporation |
4 | * Copyright (c) 2019-2021, Linaro Limited |
5 | * |
6 | * See Documentation/security/keys/trusted-encrypted.rst |
7 | */ |
8 | |
9 | #include <crypto/hash_info.h> |
10 | #include <linux/init.h> |
11 | #include <linux/slab.h> |
12 | #include <linux/parser.h> |
13 | #include <linux/string.h> |
14 | #include <linux/err.h> |
15 | #include <keys/trusted-type.h> |
16 | #include <linux/key-type.h> |
17 | #include <linux/crypto.h> |
18 | #include <crypto/hash.h> |
19 | #include <crypto/sha1.h> |
20 | #include <linux/tpm.h> |
21 | #include <linux/tpm_command.h> |
22 | |
23 | #include <keys/trusted_tpm.h> |
24 | |
25 | static const char hmac_alg[] = "hmac(sha1)" ; |
26 | static const char hash_alg[] = "sha1" ; |
27 | static struct tpm_chip *chip; |
28 | static struct tpm_digest *digests; |
29 | |
30 | struct sdesc { |
31 | struct shash_desc shash; |
32 | char ctx[]; |
33 | }; |
34 | |
35 | static struct crypto_shash *hashalg; |
36 | static struct crypto_shash *hmacalg; |
37 | |
38 | static struct sdesc *init_sdesc(struct crypto_shash *alg) |
39 | { |
40 | struct sdesc *sdesc; |
41 | int size; |
42 | |
43 | size = sizeof(struct shash_desc) + crypto_shash_descsize(tfm: alg); |
44 | sdesc = kmalloc(size, GFP_KERNEL); |
45 | if (!sdesc) |
46 | return ERR_PTR(error: -ENOMEM); |
47 | sdesc->shash.tfm = alg; |
48 | return sdesc; |
49 | } |
50 | |
51 | static int TSS_sha1(const unsigned char *data, unsigned int datalen, |
52 | unsigned char *digest) |
53 | { |
54 | struct sdesc *sdesc; |
55 | int ret; |
56 | |
57 | sdesc = init_sdesc(alg: hashalg); |
58 | if (IS_ERR(ptr: sdesc)) { |
59 | pr_info("can't alloc %s\n" , hash_alg); |
60 | return PTR_ERR(ptr: sdesc); |
61 | } |
62 | |
63 | ret = crypto_shash_digest(desc: &sdesc->shash, data, len: datalen, out: digest); |
64 | kfree_sensitive(objp: sdesc); |
65 | return ret; |
66 | } |
67 | |
68 | static int TSS_rawhmac(unsigned char *digest, const unsigned char *key, |
69 | unsigned int keylen, ...) |
70 | { |
71 | struct sdesc *sdesc; |
72 | va_list argp; |
73 | unsigned int dlen; |
74 | unsigned char *data; |
75 | int ret; |
76 | |
77 | sdesc = init_sdesc(alg: hmacalg); |
78 | if (IS_ERR(ptr: sdesc)) { |
79 | pr_info("can't alloc %s\n" , hmac_alg); |
80 | return PTR_ERR(ptr: sdesc); |
81 | } |
82 | |
83 | ret = crypto_shash_setkey(tfm: hmacalg, key, keylen); |
84 | if (ret < 0) |
85 | goto out; |
86 | ret = crypto_shash_init(desc: &sdesc->shash); |
87 | if (ret < 0) |
88 | goto out; |
89 | |
90 | va_start(argp, keylen); |
91 | for (;;) { |
92 | dlen = va_arg(argp, unsigned int); |
93 | if (dlen == 0) |
94 | break; |
95 | data = va_arg(argp, unsigned char *); |
96 | if (data == NULL) { |
97 | ret = -EINVAL; |
98 | break; |
99 | } |
100 | ret = crypto_shash_update(desc: &sdesc->shash, data, len: dlen); |
101 | if (ret < 0) |
102 | break; |
103 | } |
104 | va_end(argp); |
105 | if (!ret) |
106 | ret = crypto_shash_final(desc: &sdesc->shash, out: digest); |
107 | out: |
108 | kfree_sensitive(objp: sdesc); |
109 | return ret; |
110 | } |
111 | |
112 | /* |
113 | * calculate authorization info fields to send to TPM |
114 | */ |
115 | int TSS_authhmac(unsigned char *digest, const unsigned char *key, |
116 | unsigned int keylen, unsigned char *h1, |
117 | unsigned char *h2, unsigned int h3, ...) |
118 | { |
119 | unsigned char paramdigest[SHA1_DIGEST_SIZE]; |
120 | struct sdesc *sdesc; |
121 | unsigned int dlen; |
122 | unsigned char *data; |
123 | unsigned char c; |
124 | int ret; |
125 | va_list argp; |
126 | |
127 | if (!chip) |
128 | return -ENODEV; |
129 | |
130 | sdesc = init_sdesc(alg: hashalg); |
131 | if (IS_ERR(ptr: sdesc)) { |
132 | pr_info("can't alloc %s\n" , hash_alg); |
133 | return PTR_ERR(ptr: sdesc); |
134 | } |
135 | |
136 | c = !!h3; |
137 | ret = crypto_shash_init(desc: &sdesc->shash); |
138 | if (ret < 0) |
139 | goto out; |
140 | va_start(argp, h3); |
141 | for (;;) { |
142 | dlen = va_arg(argp, unsigned int); |
143 | if (dlen == 0) |
144 | break; |
145 | data = va_arg(argp, unsigned char *); |
146 | if (!data) { |
147 | ret = -EINVAL; |
148 | break; |
149 | } |
150 | ret = crypto_shash_update(desc: &sdesc->shash, data, len: dlen); |
151 | if (ret < 0) |
152 | break; |
153 | } |
154 | va_end(argp); |
155 | if (!ret) |
156 | ret = crypto_shash_final(desc: &sdesc->shash, out: paramdigest); |
157 | if (!ret) |
158 | ret = TSS_rawhmac(digest, key, keylen, SHA1_DIGEST_SIZE, |
159 | paramdigest, TPM_NONCE_SIZE, h1, |
160 | TPM_NONCE_SIZE, h2, 1, &c, 0, 0); |
161 | out: |
162 | kfree_sensitive(objp: sdesc); |
163 | return ret; |
164 | } |
165 | EXPORT_SYMBOL_GPL(TSS_authhmac); |
166 | |
167 | /* |
168 | * verify the AUTH1_COMMAND (Seal) result from TPM |
169 | */ |
170 | int TSS_checkhmac1(unsigned char *buffer, |
171 | const uint32_t command, |
172 | const unsigned char *ononce, |
173 | const unsigned char *key, |
174 | unsigned int keylen, ...) |
175 | { |
176 | uint32_t bufsize; |
177 | uint16_t tag; |
178 | uint32_t ordinal; |
179 | uint32_t result; |
180 | unsigned char *enonce; |
181 | unsigned char *continueflag; |
182 | unsigned char *authdata; |
183 | unsigned char testhmac[SHA1_DIGEST_SIZE]; |
184 | unsigned char paramdigest[SHA1_DIGEST_SIZE]; |
185 | struct sdesc *sdesc; |
186 | unsigned int dlen; |
187 | unsigned int dpos; |
188 | va_list argp; |
189 | int ret; |
190 | |
191 | if (!chip) |
192 | return -ENODEV; |
193 | |
194 | bufsize = LOAD32(buffer, TPM_SIZE_OFFSET); |
195 | tag = LOAD16(buffer, 0); |
196 | ordinal = command; |
197 | result = LOAD32N(buffer, TPM_RETURN_OFFSET); |
198 | if (tag == TPM_TAG_RSP_COMMAND) |
199 | return 0; |
200 | if (tag != TPM_TAG_RSP_AUTH1_COMMAND) |
201 | return -EINVAL; |
202 | authdata = buffer + bufsize - SHA1_DIGEST_SIZE; |
203 | continueflag = authdata - 1; |
204 | enonce = continueflag - TPM_NONCE_SIZE; |
205 | |
206 | sdesc = init_sdesc(alg: hashalg); |
207 | if (IS_ERR(ptr: sdesc)) { |
208 | pr_info("can't alloc %s\n" , hash_alg); |
209 | return PTR_ERR(ptr: sdesc); |
210 | } |
211 | ret = crypto_shash_init(desc: &sdesc->shash); |
212 | if (ret < 0) |
213 | goto out; |
214 | ret = crypto_shash_update(desc: &sdesc->shash, data: (const u8 *)&result, |
215 | len: sizeof result); |
216 | if (ret < 0) |
217 | goto out; |
218 | ret = crypto_shash_update(desc: &sdesc->shash, data: (const u8 *)&ordinal, |
219 | len: sizeof ordinal); |
220 | if (ret < 0) |
221 | goto out; |
222 | va_start(argp, keylen); |
223 | for (;;) { |
224 | dlen = va_arg(argp, unsigned int); |
225 | if (dlen == 0) |
226 | break; |
227 | dpos = va_arg(argp, unsigned int); |
228 | ret = crypto_shash_update(desc: &sdesc->shash, data: buffer + dpos, len: dlen); |
229 | if (ret < 0) |
230 | break; |
231 | } |
232 | va_end(argp); |
233 | if (!ret) |
234 | ret = crypto_shash_final(desc: &sdesc->shash, out: paramdigest); |
235 | if (ret < 0) |
236 | goto out; |
237 | |
238 | ret = TSS_rawhmac(digest: testhmac, key, keylen, SHA1_DIGEST_SIZE, paramdigest, |
239 | TPM_NONCE_SIZE, enonce, TPM_NONCE_SIZE, ononce, |
240 | 1, continueflag, 0, 0); |
241 | if (ret < 0) |
242 | goto out; |
243 | |
244 | if (memcmp(p: testhmac, q: authdata, SHA1_DIGEST_SIZE)) |
245 | ret = -EINVAL; |
246 | out: |
247 | kfree_sensitive(objp: sdesc); |
248 | return ret; |
249 | } |
250 | EXPORT_SYMBOL_GPL(TSS_checkhmac1); |
251 | |
252 | /* |
253 | * verify the AUTH2_COMMAND (unseal) result from TPM |
254 | */ |
255 | static int TSS_checkhmac2(unsigned char *buffer, |
256 | const uint32_t command, |
257 | const unsigned char *ononce, |
258 | const unsigned char *key1, |
259 | unsigned int keylen1, |
260 | const unsigned char *key2, |
261 | unsigned int keylen2, ...) |
262 | { |
263 | uint32_t bufsize; |
264 | uint16_t tag; |
265 | uint32_t ordinal; |
266 | uint32_t result; |
267 | unsigned char *enonce1; |
268 | unsigned char *continueflag1; |
269 | unsigned char *authdata1; |
270 | unsigned char *enonce2; |
271 | unsigned char *continueflag2; |
272 | unsigned char *authdata2; |
273 | unsigned char testhmac1[SHA1_DIGEST_SIZE]; |
274 | unsigned char testhmac2[SHA1_DIGEST_SIZE]; |
275 | unsigned char paramdigest[SHA1_DIGEST_SIZE]; |
276 | struct sdesc *sdesc; |
277 | unsigned int dlen; |
278 | unsigned int dpos; |
279 | va_list argp; |
280 | int ret; |
281 | |
282 | bufsize = LOAD32(buffer, TPM_SIZE_OFFSET); |
283 | tag = LOAD16(buffer, 0); |
284 | ordinal = command; |
285 | result = LOAD32N(buffer, TPM_RETURN_OFFSET); |
286 | |
287 | if (tag == TPM_TAG_RSP_COMMAND) |
288 | return 0; |
289 | if (tag != TPM_TAG_RSP_AUTH2_COMMAND) |
290 | return -EINVAL; |
291 | authdata1 = buffer + bufsize - (SHA1_DIGEST_SIZE + 1 |
292 | + SHA1_DIGEST_SIZE + SHA1_DIGEST_SIZE); |
293 | authdata2 = buffer + bufsize - (SHA1_DIGEST_SIZE); |
294 | continueflag1 = authdata1 - 1; |
295 | continueflag2 = authdata2 - 1; |
296 | enonce1 = continueflag1 - TPM_NONCE_SIZE; |
297 | enonce2 = continueflag2 - TPM_NONCE_SIZE; |
298 | |
299 | sdesc = init_sdesc(alg: hashalg); |
300 | if (IS_ERR(ptr: sdesc)) { |
301 | pr_info("can't alloc %s\n" , hash_alg); |
302 | return PTR_ERR(ptr: sdesc); |
303 | } |
304 | ret = crypto_shash_init(desc: &sdesc->shash); |
305 | if (ret < 0) |
306 | goto out; |
307 | ret = crypto_shash_update(desc: &sdesc->shash, data: (const u8 *)&result, |
308 | len: sizeof result); |
309 | if (ret < 0) |
310 | goto out; |
311 | ret = crypto_shash_update(desc: &sdesc->shash, data: (const u8 *)&ordinal, |
312 | len: sizeof ordinal); |
313 | if (ret < 0) |
314 | goto out; |
315 | |
316 | va_start(argp, keylen2); |
317 | for (;;) { |
318 | dlen = va_arg(argp, unsigned int); |
319 | if (dlen == 0) |
320 | break; |
321 | dpos = va_arg(argp, unsigned int); |
322 | ret = crypto_shash_update(desc: &sdesc->shash, data: buffer + dpos, len: dlen); |
323 | if (ret < 0) |
324 | break; |
325 | } |
326 | va_end(argp); |
327 | if (!ret) |
328 | ret = crypto_shash_final(desc: &sdesc->shash, out: paramdigest); |
329 | if (ret < 0) |
330 | goto out; |
331 | |
332 | ret = TSS_rawhmac(digest: testhmac1, key: key1, keylen: keylen1, SHA1_DIGEST_SIZE, |
333 | paramdigest, TPM_NONCE_SIZE, enonce1, |
334 | TPM_NONCE_SIZE, ononce, 1, continueflag1, 0, 0); |
335 | if (ret < 0) |
336 | goto out; |
337 | if (memcmp(p: testhmac1, q: authdata1, SHA1_DIGEST_SIZE)) { |
338 | ret = -EINVAL; |
339 | goto out; |
340 | } |
341 | ret = TSS_rawhmac(digest: testhmac2, key: key2, keylen: keylen2, SHA1_DIGEST_SIZE, |
342 | paramdigest, TPM_NONCE_SIZE, enonce2, |
343 | TPM_NONCE_SIZE, ononce, 1, continueflag2, 0, 0); |
344 | if (ret < 0) |
345 | goto out; |
346 | if (memcmp(p: testhmac2, q: authdata2, SHA1_DIGEST_SIZE)) |
347 | ret = -EINVAL; |
348 | out: |
349 | kfree_sensitive(objp: sdesc); |
350 | return ret; |
351 | } |
352 | |
353 | /* |
354 | * For key specific tpm requests, we will generate and send our |
355 | * own TPM command packets using the drivers send function. |
356 | */ |
357 | int trusted_tpm_send(unsigned char *cmd, size_t buflen) |
358 | { |
359 | int rc; |
360 | |
361 | if (!chip) |
362 | return -ENODEV; |
363 | |
364 | dump_tpm_buf(buf: cmd); |
365 | rc = tpm_send(chip, cmd, buflen); |
366 | dump_tpm_buf(buf: cmd); |
367 | if (rc > 0) |
368 | /* Can't return positive return codes values to keyctl */ |
369 | rc = -EPERM; |
370 | return rc; |
371 | } |
372 | EXPORT_SYMBOL_GPL(trusted_tpm_send); |
373 | |
374 | /* |
375 | * Lock a trusted key, by extending a selected PCR. |
376 | * |
377 | * Prevents a trusted key that is sealed to PCRs from being accessed. |
378 | * This uses the tpm driver's extend function. |
379 | */ |
380 | static int pcrlock(const int pcrnum) |
381 | { |
382 | if (!capable(CAP_SYS_ADMIN)) |
383 | return -EPERM; |
384 | |
385 | return tpm_pcr_extend(chip, pcr_idx: pcrnum, digests) ? -EINVAL : 0; |
386 | } |
387 | |
388 | /* |
389 | * Create an object specific authorisation protocol (OSAP) session |
390 | */ |
391 | static int osap(struct tpm_buf *tb, struct osapsess *s, |
392 | const unsigned char *key, uint16_t type, uint32_t handle) |
393 | { |
394 | unsigned char enonce[TPM_NONCE_SIZE]; |
395 | unsigned char ononce[TPM_NONCE_SIZE]; |
396 | int ret; |
397 | |
398 | ret = tpm_get_random(chip, data: ononce, TPM_NONCE_SIZE); |
399 | if (ret < 0) |
400 | return ret; |
401 | |
402 | if (ret != TPM_NONCE_SIZE) |
403 | return -EIO; |
404 | |
405 | tpm_buf_reset(buf: tb, TPM_TAG_RQU_COMMAND, TPM_ORD_OSAP); |
406 | tpm_buf_append_u16(buf: tb, value: type); |
407 | tpm_buf_append_u32(buf: tb, value: handle); |
408 | tpm_buf_append(buf: tb, new_data: ononce, TPM_NONCE_SIZE); |
409 | |
410 | ret = trusted_tpm_send(tb->data, MAX_BUF_SIZE); |
411 | if (ret < 0) |
412 | return ret; |
413 | |
414 | s->handle = LOAD32(tb->data, TPM_DATA_OFFSET); |
415 | memcpy(s->enonce, &(tb->data[TPM_DATA_OFFSET + sizeof(uint32_t)]), |
416 | TPM_NONCE_SIZE); |
417 | memcpy(enonce, &(tb->data[TPM_DATA_OFFSET + sizeof(uint32_t) + |
418 | TPM_NONCE_SIZE]), TPM_NONCE_SIZE); |
419 | return TSS_rawhmac(digest: s->secret, key, SHA1_DIGEST_SIZE, TPM_NONCE_SIZE, |
420 | enonce, TPM_NONCE_SIZE, ononce, 0, 0); |
421 | } |
422 | |
423 | /* |
424 | * Create an object independent authorisation protocol (oiap) session |
425 | */ |
426 | int oiap(struct tpm_buf *tb, uint32_t *handle, unsigned char *nonce) |
427 | { |
428 | int ret; |
429 | |
430 | if (!chip) |
431 | return -ENODEV; |
432 | |
433 | tpm_buf_reset(buf: tb, TPM_TAG_RQU_COMMAND, TPM_ORD_OIAP); |
434 | ret = trusted_tpm_send(tb->data, MAX_BUF_SIZE); |
435 | if (ret < 0) |
436 | return ret; |
437 | |
438 | *handle = LOAD32(tb->data, TPM_DATA_OFFSET); |
439 | memcpy(nonce, &tb->data[TPM_DATA_OFFSET + sizeof(uint32_t)], |
440 | TPM_NONCE_SIZE); |
441 | return 0; |
442 | } |
443 | EXPORT_SYMBOL_GPL(oiap); |
444 | |
445 | struct tpm_digests { |
446 | unsigned char encauth[SHA1_DIGEST_SIZE]; |
447 | unsigned char pubauth[SHA1_DIGEST_SIZE]; |
448 | unsigned char xorwork[SHA1_DIGEST_SIZE * 2]; |
449 | unsigned char xorhash[SHA1_DIGEST_SIZE]; |
450 | unsigned char nonceodd[TPM_NONCE_SIZE]; |
451 | }; |
452 | |
453 | /* |
454 | * Have the TPM seal(encrypt) the trusted key, possibly based on |
455 | * Platform Configuration Registers (PCRs). AUTH1 for sealing key. |
456 | */ |
457 | static int tpm_seal(struct tpm_buf *tb, uint16_t keytype, |
458 | uint32_t keyhandle, const unsigned char *keyauth, |
459 | const unsigned char *data, uint32_t datalen, |
460 | unsigned char *blob, uint32_t *bloblen, |
461 | const unsigned char *blobauth, |
462 | const unsigned char *pcrinfo, uint32_t pcrinfosize) |
463 | { |
464 | struct osapsess sess; |
465 | struct tpm_digests *td; |
466 | unsigned char cont; |
467 | uint32_t ordinal; |
468 | uint32_t pcrsize; |
469 | uint32_t datsize; |
470 | int sealinfosize; |
471 | int encdatasize; |
472 | int storedsize; |
473 | int ret; |
474 | int i; |
475 | |
476 | /* alloc some work space for all the hashes */ |
477 | td = kmalloc(size: sizeof *td, GFP_KERNEL); |
478 | if (!td) |
479 | return -ENOMEM; |
480 | |
481 | /* get session for sealing key */ |
482 | ret = osap(tb, s: &sess, key: keyauth, type: keytype, handle: keyhandle); |
483 | if (ret < 0) |
484 | goto out; |
485 | dump_sess(s: &sess); |
486 | |
487 | /* calculate encrypted authorization value */ |
488 | memcpy(td->xorwork, sess.secret, SHA1_DIGEST_SIZE); |
489 | memcpy(td->xorwork + SHA1_DIGEST_SIZE, sess.enonce, SHA1_DIGEST_SIZE); |
490 | ret = TSS_sha1(data: td->xorwork, SHA1_DIGEST_SIZE * 2, digest: td->xorhash); |
491 | if (ret < 0) |
492 | goto out; |
493 | |
494 | ret = tpm_get_random(chip, data: td->nonceodd, TPM_NONCE_SIZE); |
495 | if (ret < 0) |
496 | goto out; |
497 | |
498 | if (ret != TPM_NONCE_SIZE) { |
499 | ret = -EIO; |
500 | goto out; |
501 | } |
502 | |
503 | ordinal = htonl(TPM_ORD_SEAL); |
504 | datsize = htonl(datalen); |
505 | pcrsize = htonl(pcrinfosize); |
506 | cont = 0; |
507 | |
508 | /* encrypt data authorization key */ |
509 | for (i = 0; i < SHA1_DIGEST_SIZE; ++i) |
510 | td->encauth[i] = td->xorhash[i] ^ blobauth[i]; |
511 | |
512 | /* calculate authorization HMAC value */ |
513 | if (pcrinfosize == 0) { |
514 | /* no pcr info specified */ |
515 | ret = TSS_authhmac(td->pubauth, sess.secret, SHA1_DIGEST_SIZE, |
516 | sess.enonce, td->nonceodd, cont, |
517 | sizeof(uint32_t), &ordinal, SHA1_DIGEST_SIZE, |
518 | td->encauth, sizeof(uint32_t), &pcrsize, |
519 | sizeof(uint32_t), &datsize, datalen, data, 0, |
520 | 0); |
521 | } else { |
522 | /* pcr info specified */ |
523 | ret = TSS_authhmac(td->pubauth, sess.secret, SHA1_DIGEST_SIZE, |
524 | sess.enonce, td->nonceodd, cont, |
525 | sizeof(uint32_t), &ordinal, SHA1_DIGEST_SIZE, |
526 | td->encauth, sizeof(uint32_t), &pcrsize, |
527 | pcrinfosize, pcrinfo, sizeof(uint32_t), |
528 | &datsize, datalen, data, 0, 0); |
529 | } |
530 | if (ret < 0) |
531 | goto out; |
532 | |
533 | /* build and send the TPM request packet */ |
534 | tpm_buf_reset(buf: tb, TPM_TAG_RQU_AUTH1_COMMAND, TPM_ORD_SEAL); |
535 | tpm_buf_append_u32(buf: tb, value: keyhandle); |
536 | tpm_buf_append(buf: tb, new_data: td->encauth, SHA1_DIGEST_SIZE); |
537 | tpm_buf_append_u32(buf: tb, value: pcrinfosize); |
538 | tpm_buf_append(buf: tb, new_data: pcrinfo, new_len: pcrinfosize); |
539 | tpm_buf_append_u32(buf: tb, value: datalen); |
540 | tpm_buf_append(buf: tb, new_data: data, new_len: datalen); |
541 | tpm_buf_append_u32(buf: tb, value: sess.handle); |
542 | tpm_buf_append(buf: tb, new_data: td->nonceodd, TPM_NONCE_SIZE); |
543 | tpm_buf_append_u8(buf: tb, value: cont); |
544 | tpm_buf_append(buf: tb, new_data: td->pubauth, SHA1_DIGEST_SIZE); |
545 | |
546 | ret = trusted_tpm_send(tb->data, MAX_BUF_SIZE); |
547 | if (ret < 0) |
548 | goto out; |
549 | |
550 | /* calculate the size of the returned Blob */ |
551 | sealinfosize = LOAD32(tb->data, TPM_DATA_OFFSET + sizeof(uint32_t)); |
552 | encdatasize = LOAD32(tb->data, TPM_DATA_OFFSET + sizeof(uint32_t) + |
553 | sizeof(uint32_t) + sealinfosize); |
554 | storedsize = sizeof(uint32_t) + sizeof(uint32_t) + sealinfosize + |
555 | sizeof(uint32_t) + encdatasize; |
556 | |
557 | /* check the HMAC in the response */ |
558 | ret = TSS_checkhmac1(tb->data, ordinal, td->nonceodd, sess.secret, |
559 | SHA1_DIGEST_SIZE, storedsize, TPM_DATA_OFFSET, 0, |
560 | 0); |
561 | |
562 | /* copy the returned blob to caller */ |
563 | if (!ret) { |
564 | memcpy(blob, tb->data + TPM_DATA_OFFSET, storedsize); |
565 | *bloblen = storedsize; |
566 | } |
567 | out: |
568 | kfree_sensitive(objp: td); |
569 | return ret; |
570 | } |
571 | |
572 | /* |
573 | * use the AUTH2_COMMAND form of unseal, to authorize both key and blob |
574 | */ |
575 | static int tpm_unseal(struct tpm_buf *tb, |
576 | uint32_t keyhandle, const unsigned char *keyauth, |
577 | const unsigned char *blob, int bloblen, |
578 | const unsigned char *blobauth, |
579 | unsigned char *data, unsigned int *datalen) |
580 | { |
581 | unsigned char nonceodd[TPM_NONCE_SIZE]; |
582 | unsigned char enonce1[TPM_NONCE_SIZE]; |
583 | unsigned char enonce2[TPM_NONCE_SIZE]; |
584 | unsigned char authdata1[SHA1_DIGEST_SIZE]; |
585 | unsigned char authdata2[SHA1_DIGEST_SIZE]; |
586 | uint32_t authhandle1 = 0; |
587 | uint32_t authhandle2 = 0; |
588 | unsigned char cont = 0; |
589 | uint32_t ordinal; |
590 | int ret; |
591 | |
592 | /* sessions for unsealing key and data */ |
593 | ret = oiap(tb, &authhandle1, enonce1); |
594 | if (ret < 0) { |
595 | pr_info("oiap failed (%d)\n" , ret); |
596 | return ret; |
597 | } |
598 | ret = oiap(tb, &authhandle2, enonce2); |
599 | if (ret < 0) { |
600 | pr_info("oiap failed (%d)\n" , ret); |
601 | return ret; |
602 | } |
603 | |
604 | ordinal = htonl(TPM_ORD_UNSEAL); |
605 | ret = tpm_get_random(chip, data: nonceodd, TPM_NONCE_SIZE); |
606 | if (ret < 0) |
607 | return ret; |
608 | |
609 | if (ret != TPM_NONCE_SIZE) { |
610 | pr_info("tpm_get_random failed (%d)\n" , ret); |
611 | return -EIO; |
612 | } |
613 | ret = TSS_authhmac(authdata1, keyauth, TPM_NONCE_SIZE, |
614 | enonce1, nonceodd, cont, sizeof(uint32_t), |
615 | &ordinal, bloblen, blob, 0, 0); |
616 | if (ret < 0) |
617 | return ret; |
618 | ret = TSS_authhmac(authdata2, blobauth, TPM_NONCE_SIZE, |
619 | enonce2, nonceodd, cont, sizeof(uint32_t), |
620 | &ordinal, bloblen, blob, 0, 0); |
621 | if (ret < 0) |
622 | return ret; |
623 | |
624 | /* build and send TPM request packet */ |
625 | tpm_buf_reset(buf: tb, TPM_TAG_RQU_AUTH2_COMMAND, TPM_ORD_UNSEAL); |
626 | tpm_buf_append_u32(buf: tb, value: keyhandle); |
627 | tpm_buf_append(buf: tb, new_data: blob, new_len: bloblen); |
628 | tpm_buf_append_u32(buf: tb, value: authhandle1); |
629 | tpm_buf_append(buf: tb, new_data: nonceodd, TPM_NONCE_SIZE); |
630 | tpm_buf_append_u8(buf: tb, value: cont); |
631 | tpm_buf_append(buf: tb, new_data: authdata1, SHA1_DIGEST_SIZE); |
632 | tpm_buf_append_u32(buf: tb, value: authhandle2); |
633 | tpm_buf_append(buf: tb, new_data: nonceodd, TPM_NONCE_SIZE); |
634 | tpm_buf_append_u8(buf: tb, value: cont); |
635 | tpm_buf_append(buf: tb, new_data: authdata2, SHA1_DIGEST_SIZE); |
636 | |
637 | ret = trusted_tpm_send(tb->data, MAX_BUF_SIZE); |
638 | if (ret < 0) { |
639 | pr_info("authhmac failed (%d)\n" , ret); |
640 | return ret; |
641 | } |
642 | |
643 | *datalen = LOAD32(tb->data, TPM_DATA_OFFSET); |
644 | ret = TSS_checkhmac2(buffer: tb->data, command: ordinal, ononce: nonceodd, |
645 | key1: keyauth, SHA1_DIGEST_SIZE, |
646 | key2: 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("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 | */ |
661 | static 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 | ret = tpm_buf_init(buf: &tb, tag: 0, ordinal: 0); |
668 | if (ret) |
669 | return ret; |
670 | |
671 | /* include migratable flag at end of sealed key */ |
672 | p->key[p->key_len] = p->migratable; |
673 | |
674 | ret = tpm_seal(tb: &tb, keytype: o->keytype, keyhandle: o->keyhandle, keyauth: o->keyauth, |
675 | data: p->key, datalen: p->key_len + 1, blob: p->blob, bloblen: &p->blob_len, |
676 | blobauth: o->blobauth, pcrinfo: o->pcrinfo, pcrinfosize: o->pcrinfo_len); |
677 | if (ret < 0) |
678 | pr_info("srkseal failed (%d)\n" , ret); |
679 | |
680 | tpm_buf_destroy(buf: &tb); |
681 | return ret; |
682 | } |
683 | |
684 | /* |
685 | * Have the TPM unseal(decrypt) the symmetric key |
686 | */ |
687 | static 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 | ret = tpm_buf_init(buf: &tb, tag: 0, ordinal: 0); |
694 | if (ret) |
695 | return ret; |
696 | |
697 | ret = tpm_unseal(tb: &tb, keyhandle: o->keyhandle, keyauth: o->keyauth, blob: p->blob, bloblen: p->blob_len, |
698 | blobauth: o->blobauth, data: p->key, datalen: &p->key_len); |
699 | if (ret < 0) |
700 | pr_info("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 | tpm_buf_destroy(buf: &tb); |
706 | return ret; |
707 | } |
708 | |
709 | enum { |
710 | Opt_err, |
711 | Opt_keyhandle, Opt_keyauth, Opt_blobauth, |
712 | Opt_pcrinfo, Opt_pcrlock, Opt_migratable, |
713 | Opt_hash, |
714 | Opt_policydigest, |
715 | Opt_policyhandle, |
716 | }; |
717 | |
718 | static const match_table_t key_tokens = { |
719 | {Opt_keyhandle, "keyhandle=%s" }, |
720 | {Opt_keyauth, "keyauth=%s" }, |
721 | {Opt_blobauth, "blobauth=%s" }, |
722 | {Opt_pcrinfo, "pcrinfo=%s" }, |
723 | {Opt_pcrlock, "pcrlock=%s" }, |
724 | {Opt_migratable, "migratable=%s" }, |
725 | {Opt_hash, "hash=%s" }, |
726 | {Opt_policydigest, "policydigest=%s" }, |
727 | {Opt_policyhandle, "policyhandle=%s" }, |
728 | {Opt_err, NULL} |
729 | }; |
730 | |
731 | /* can have zero or more token= options */ |
732 | static int getoptions(char *c, struct trusted_key_payload *pay, |
733 | struct trusted_key_options *opt) |
734 | { |
735 | substring_t args[MAX_OPT_ARGS]; |
736 | char *p = c; |
737 | int token; |
738 | int res; |
739 | unsigned long handle; |
740 | unsigned long lock; |
741 | unsigned long token_mask = 0; |
742 | unsigned int digest_len; |
743 | int i; |
744 | int tpm2; |
745 | |
746 | tpm2 = tpm_is_tpm2(chip); |
747 | if (tpm2 < 0) |
748 | return tpm2; |
749 | |
750 | opt->hash = tpm2 ? HASH_ALGO_SHA256 : HASH_ALGO_SHA1; |
751 | |
752 | if (!c) |
753 | return 0; |
754 | |
755 | while ((p = strsep(&c, " \t" ))) { |
756 | if (*p == '\0' || *p == ' ' || *p == '\t') |
757 | continue; |
758 | token = match_token(p, table: key_tokens, args); |
759 | if (test_and_set_bit(nr: token, addr: &token_mask)) |
760 | return -EINVAL; |
761 | |
762 | switch (token) { |
763 | case Opt_pcrinfo: |
764 | opt->pcrinfo_len = strlen(args[0].from) / 2; |
765 | if (opt->pcrinfo_len > MAX_PCRINFO_SIZE) |
766 | return -EINVAL; |
767 | res = hex2bin(dst: opt->pcrinfo, src: args[0].from, |
768 | count: opt->pcrinfo_len); |
769 | if (res < 0) |
770 | return -EINVAL; |
771 | break; |
772 | case Opt_keyhandle: |
773 | res = kstrtoul(s: args[0].from, base: 16, res: &handle); |
774 | if (res < 0) |
775 | return -EINVAL; |
776 | opt->keytype = SEAL_keytype; |
777 | opt->keyhandle = handle; |
778 | break; |
779 | case Opt_keyauth: |
780 | if (strlen(args[0].from) != 2 * SHA1_DIGEST_SIZE) |
781 | return -EINVAL; |
782 | res = hex2bin(dst: opt->keyauth, src: args[0].from, |
783 | SHA1_DIGEST_SIZE); |
784 | if (res < 0) |
785 | return -EINVAL; |
786 | break; |
787 | case Opt_blobauth: |
788 | /* |
789 | * TPM 1.2 authorizations are sha1 hashes passed in as |
790 | * hex strings. TPM 2.0 authorizations are simple |
791 | * passwords (although it can take a hash as well) |
792 | */ |
793 | opt->blobauth_len = strlen(args[0].from); |
794 | |
795 | if (opt->blobauth_len == 2 * TPM_DIGEST_SIZE) { |
796 | res = hex2bin(dst: opt->blobauth, src: args[0].from, |
797 | TPM_DIGEST_SIZE); |
798 | if (res < 0) |
799 | return -EINVAL; |
800 | |
801 | opt->blobauth_len = TPM_DIGEST_SIZE; |
802 | break; |
803 | } |
804 | |
805 | if (tpm2 && opt->blobauth_len <= sizeof(opt->blobauth)) { |
806 | memcpy(opt->blobauth, args[0].from, |
807 | opt->blobauth_len); |
808 | break; |
809 | } |
810 | |
811 | return -EINVAL; |
812 | |
813 | break; |
814 | |
815 | case Opt_migratable: |
816 | if (*args[0].from == '0') |
817 | pay->migratable = 0; |
818 | else if (*args[0].from != '1') |
819 | return -EINVAL; |
820 | break; |
821 | case Opt_pcrlock: |
822 | res = kstrtoul(s: args[0].from, base: 10, res: &lock); |
823 | if (res < 0) |
824 | return -EINVAL; |
825 | opt->pcrlock = lock; |
826 | break; |
827 | case Opt_hash: |
828 | if (test_bit(Opt_policydigest, &token_mask)) |
829 | return -EINVAL; |
830 | for (i = 0; i < HASH_ALGO__LAST; i++) { |
831 | if (!strcmp(args[0].from, hash_algo_name[i])) { |
832 | opt->hash = i; |
833 | break; |
834 | } |
835 | } |
836 | if (i == HASH_ALGO__LAST) |
837 | return -EINVAL; |
838 | if (!tpm2 && i != HASH_ALGO_SHA1) { |
839 | pr_info("TPM 1.x only supports SHA-1.\n" ); |
840 | return -EINVAL; |
841 | } |
842 | break; |
843 | case Opt_policydigest: |
844 | digest_len = hash_digest_size[opt->hash]; |
845 | if (!tpm2 || strlen(args[0].from) != (2 * digest_len)) |
846 | return -EINVAL; |
847 | res = hex2bin(dst: opt->policydigest, src: args[0].from, |
848 | count: digest_len); |
849 | if (res < 0) |
850 | return -EINVAL; |
851 | opt->policydigest_len = digest_len; |
852 | break; |
853 | case Opt_policyhandle: |
854 | if (!tpm2) |
855 | return -EINVAL; |
856 | res = kstrtoul(s: args[0].from, base: 16, res: &handle); |
857 | if (res < 0) |
858 | return -EINVAL; |
859 | opt->policyhandle = handle; |
860 | break; |
861 | default: |
862 | return -EINVAL; |
863 | } |
864 | } |
865 | return 0; |
866 | } |
867 | |
868 | static struct trusted_key_options *trusted_options_alloc(void) |
869 | { |
870 | struct trusted_key_options *options; |
871 | int tpm2; |
872 | |
873 | tpm2 = tpm_is_tpm2(chip); |
874 | if (tpm2 < 0) |
875 | return NULL; |
876 | |
877 | options = kzalloc(size: sizeof *options, GFP_KERNEL); |
878 | if (options) { |
879 | /* set any non-zero defaults */ |
880 | options->keytype = SRK_keytype; |
881 | |
882 | if (!tpm2) |
883 | options->keyhandle = SRKHANDLE; |
884 | } |
885 | return options; |
886 | } |
887 | |
888 | static int trusted_tpm_seal(struct trusted_key_payload *p, char *datablob) |
889 | { |
890 | struct trusted_key_options *options = NULL; |
891 | int ret = 0; |
892 | int tpm2; |
893 | |
894 | tpm2 = tpm_is_tpm2(chip); |
895 | if (tpm2 < 0) |
896 | return tpm2; |
897 | |
898 | options = trusted_options_alloc(); |
899 | if (!options) |
900 | return -ENOMEM; |
901 | |
902 | ret = getoptions(c: datablob, pay: p, opt: options); |
903 | if (ret < 0) |
904 | goto out; |
905 | dump_options(o: options); |
906 | |
907 | if (!options->keyhandle && !tpm2) { |
908 | ret = -EINVAL; |
909 | goto out; |
910 | } |
911 | |
912 | if (tpm2) |
913 | ret = tpm2_seal_trusted(chip, payload: p, options); |
914 | else |
915 | ret = key_seal(p, o: options); |
916 | if (ret < 0) { |
917 | pr_info("key_seal failed (%d)\n" , ret); |
918 | goto out; |
919 | } |
920 | |
921 | if (options->pcrlock) { |
922 | ret = pcrlock(pcrnum: options->pcrlock); |
923 | if (ret < 0) { |
924 | pr_info("pcrlock failed (%d)\n" , ret); |
925 | goto out; |
926 | } |
927 | } |
928 | out: |
929 | kfree_sensitive(objp: options); |
930 | return ret; |
931 | } |
932 | |
933 | static int trusted_tpm_unseal(struct trusted_key_payload *p, char *datablob) |
934 | { |
935 | struct trusted_key_options *options = NULL; |
936 | int ret = 0; |
937 | int tpm2; |
938 | |
939 | tpm2 = tpm_is_tpm2(chip); |
940 | if (tpm2 < 0) |
941 | return tpm2; |
942 | |
943 | options = trusted_options_alloc(); |
944 | if (!options) |
945 | return -ENOMEM; |
946 | |
947 | ret = getoptions(c: datablob, pay: p, opt: options); |
948 | if (ret < 0) |
949 | goto out; |
950 | dump_options(o: options); |
951 | |
952 | if (!options->keyhandle && !tpm2) { |
953 | ret = -EINVAL; |
954 | goto out; |
955 | } |
956 | |
957 | if (tpm2) |
958 | ret = tpm2_unseal_trusted(chip, payload: p, options); |
959 | else |
960 | ret = key_unseal(p, o: options); |
961 | if (ret < 0) |
962 | pr_info("key_unseal failed (%d)\n" , ret); |
963 | |
964 | if (options->pcrlock) { |
965 | ret = pcrlock(pcrnum: options->pcrlock); |
966 | if (ret < 0) { |
967 | pr_info("pcrlock failed (%d)\n" , ret); |
968 | goto out; |
969 | } |
970 | } |
971 | out: |
972 | kfree_sensitive(objp: options); |
973 | return ret; |
974 | } |
975 | |
976 | static int trusted_tpm_get_random(unsigned char *key, size_t key_len) |
977 | { |
978 | return tpm_get_random(chip, data: key, max: key_len); |
979 | } |
980 | |
981 | static void trusted_shash_release(void) |
982 | { |
983 | if (hashalg) |
984 | crypto_free_shash(tfm: hashalg); |
985 | if (hmacalg) |
986 | crypto_free_shash(tfm: hmacalg); |
987 | } |
988 | |
989 | static int __init trusted_shash_alloc(void) |
990 | { |
991 | int ret; |
992 | |
993 | hmacalg = crypto_alloc_shash(alg_name: hmac_alg, type: 0, mask: 0); |
994 | if (IS_ERR(ptr: hmacalg)) { |
995 | pr_info("could not allocate crypto %s\n" , |
996 | hmac_alg); |
997 | return PTR_ERR(ptr: hmacalg); |
998 | } |
999 | |
1000 | hashalg = crypto_alloc_shash(alg_name: hash_alg, type: 0, mask: 0); |
1001 | if (IS_ERR(ptr: hashalg)) { |
1002 | pr_info("could not allocate crypto %s\n" , |
1003 | hash_alg); |
1004 | ret = PTR_ERR(ptr: hashalg); |
1005 | goto hashalg_fail; |
1006 | } |
1007 | |
1008 | return 0; |
1009 | |
1010 | hashalg_fail: |
1011 | crypto_free_shash(tfm: hmacalg); |
1012 | return ret; |
1013 | } |
1014 | |
1015 | static int __init init_digests(void) |
1016 | { |
1017 | int i; |
1018 | |
1019 | digests = kcalloc(n: chip->nr_allocated_banks, size: sizeof(*digests), |
1020 | GFP_KERNEL); |
1021 | if (!digests) |
1022 | return -ENOMEM; |
1023 | |
1024 | for (i = 0; i < chip->nr_allocated_banks; i++) |
1025 | digests[i].alg_id = chip->allocated_banks[i].alg_id; |
1026 | |
1027 | return 0; |
1028 | } |
1029 | |
1030 | static int __init trusted_tpm_init(void) |
1031 | { |
1032 | int ret; |
1033 | |
1034 | chip = tpm_default_chip(); |
1035 | if (!chip) |
1036 | return -ENODEV; |
1037 | |
1038 | ret = init_digests(); |
1039 | if (ret < 0) |
1040 | goto err_put; |
1041 | ret = trusted_shash_alloc(); |
1042 | if (ret < 0) |
1043 | goto err_free; |
1044 | ret = register_key_type(ktype: &key_type_trusted); |
1045 | if (ret < 0) |
1046 | goto err_release; |
1047 | return 0; |
1048 | err_release: |
1049 | trusted_shash_release(); |
1050 | err_free: |
1051 | kfree(objp: digests); |
1052 | err_put: |
1053 | put_device(dev: &chip->dev); |
1054 | return ret; |
1055 | } |
1056 | |
1057 | static void trusted_tpm_exit(void) |
1058 | { |
1059 | if (chip) { |
1060 | put_device(dev: &chip->dev); |
1061 | kfree(objp: digests); |
1062 | trusted_shash_release(); |
1063 | unregister_key_type(ktype: &key_type_trusted); |
1064 | } |
1065 | } |
1066 | |
1067 | struct trusted_key_ops trusted_key_tpm_ops = { |
1068 | .migratable = 1, /* migratable by default */ |
1069 | .init = trusted_tpm_init, |
1070 | .seal = trusted_tpm_seal, |
1071 | .unseal = trusted_tpm_unseal, |
1072 | .get_random = trusted_tpm_get_random, |
1073 | .exit = trusted_tpm_exit, |
1074 | }; |
1075 | |