1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2004 IBM Corporation
4 * Copyright (C) 2014 Intel Corporation
5 */
6
7 #include <linux/asn1_encoder.h>
8 #include <linux/oid_registry.h>
9 #include <linux/string.h>
10 #include <linux/err.h>
11 #include <linux/tpm.h>
12 #include <linux/tpm_command.h>
13
14 #include <keys/trusted-type.h>
15 #include <keys/trusted_tpm.h>
16
17 #include <asm/unaligned.h>
18
19 #include "tpm2key.asn1.h"
20
21 static struct tpm2_hash tpm2_hash_map[] = {
22 {HASH_ALGO_SHA1, TPM_ALG_SHA1},
23 {HASH_ALGO_SHA256, TPM_ALG_SHA256},
24 {HASH_ALGO_SHA384, TPM_ALG_SHA384},
25 {HASH_ALGO_SHA512, TPM_ALG_SHA512},
26 {HASH_ALGO_SM3_256, TPM_ALG_SM3_256},
27 };
28
29 static u32 tpm2key_oid[] = { 2, 23, 133, 10, 1, 5 };
30
tpm2_key_encode(struct trusted_key_payload * payload,struct trusted_key_options * options,u8 * src,u32 len)31 static int tpm2_key_encode(struct trusted_key_payload *payload,
32 struct trusted_key_options *options,
33 u8 *src, u32 len)
34 {
35 const int SCRATCH_SIZE = PAGE_SIZE;
36 u8 *scratch = kmalloc(SCRATCH_SIZE, GFP_KERNEL);
37 u8 *work = scratch, *work1;
38 u8 *end_work = scratch + SCRATCH_SIZE;
39 u8 *priv, *pub;
40 u16 priv_len, pub_len;
41
42 priv_len = get_unaligned_be16(src) + 2;
43 priv = src;
44
45 src += priv_len;
46
47 pub_len = get_unaligned_be16(src) + 2;
48 pub = src;
49
50 if (!scratch)
51 return -ENOMEM;
52
53 work = asn1_encode_oid(work, end_work, tpm2key_oid,
54 asn1_oid_len(tpm2key_oid));
55
56 if (options->blobauth_len == 0) {
57 unsigned char bool[3], *w = bool;
58 /* tag 0 is emptyAuth */
59 w = asn1_encode_boolean(w, w + sizeof(bool), true);
60 if (WARN(IS_ERR(w), "BUG: Boolean failed to encode"))
61 return PTR_ERR(w);
62 work = asn1_encode_tag(work, end_work, 0, bool, w - bool);
63 }
64
65 /*
66 * Assume both octet strings will encode to a 2 byte definite length
67 *
68 * Note: For a well behaved TPM, this warning should never
69 * trigger, so if it does there's something nefarious going on
70 */
71 if (WARN(work - scratch + pub_len + priv_len + 14 > SCRATCH_SIZE,
72 "BUG: scratch buffer is too small"))
73 return -EINVAL;
74
75 work = asn1_encode_integer(work, end_work, options->keyhandle);
76 work = asn1_encode_octet_string(work, end_work, pub, pub_len);
77 work = asn1_encode_octet_string(work, end_work, priv, priv_len);
78
79 work1 = payload->blob;
80 work1 = asn1_encode_sequence(work1, work1 + sizeof(payload->blob),
81 scratch, work - scratch);
82 if (WARN(IS_ERR(work1), "BUG: ASN.1 encoder failed"))
83 return PTR_ERR(work1);
84
85 return work1 - payload->blob;
86 }
87
88 struct tpm2_key_context {
89 u32 parent;
90 const u8 *pub;
91 u32 pub_len;
92 const u8 *priv;
93 u32 priv_len;
94 };
95
tpm2_key_decode(struct trusted_key_payload * payload,struct trusted_key_options * options,u8 ** buf)96 static int tpm2_key_decode(struct trusted_key_payload *payload,
97 struct trusted_key_options *options,
98 u8 **buf)
99 {
100 int ret;
101 struct tpm2_key_context ctx;
102 u8 *blob;
103
104 memset(&ctx, 0, sizeof(ctx));
105
106 ret = asn1_ber_decoder(&tpm2key_decoder, &ctx, payload->blob,
107 payload->blob_len);
108 if (ret < 0)
109 return ret;
110
111 if (ctx.priv_len + ctx.pub_len > MAX_BLOB_SIZE)
112 return -EINVAL;
113
114 blob = kmalloc(ctx.priv_len + ctx.pub_len + 4, GFP_KERNEL);
115 if (!blob)
116 return -ENOMEM;
117
118 *buf = blob;
119 options->keyhandle = ctx.parent;
120
121 memcpy(blob, ctx.priv, ctx.priv_len);
122 blob += ctx.priv_len;
123
124 memcpy(blob, ctx.pub, ctx.pub_len);
125
126 return 0;
127 }
128
tpm2_key_parent(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)129 int tpm2_key_parent(void *context, size_t hdrlen,
130 unsigned char tag,
131 const void *value, size_t vlen)
132 {
133 struct tpm2_key_context *ctx = context;
134 const u8 *v = value;
135 int i;
136
137 ctx->parent = 0;
138 for (i = 0; i < vlen; i++) {
139 ctx->parent <<= 8;
140 ctx->parent |= v[i];
141 }
142
143 return 0;
144 }
145
tpm2_key_type(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)146 int tpm2_key_type(void *context, size_t hdrlen,
147 unsigned char tag,
148 const void *value, size_t vlen)
149 {
150 enum OID oid = look_up_OID(value, vlen);
151
152 if (oid != OID_TPMSealedData) {
153 char buffer[50];
154
155 sprint_oid(value, vlen, buffer, sizeof(buffer));
156 pr_debug("OID is \"%s\" which is not TPMSealedData\n",
157 buffer);
158 return -EINVAL;
159 }
160
161 return 0;
162 }
163
tpm2_key_pub(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)164 int tpm2_key_pub(void *context, size_t hdrlen,
165 unsigned char tag,
166 const void *value, size_t vlen)
167 {
168 struct tpm2_key_context *ctx = context;
169
170 ctx->pub = value;
171 ctx->pub_len = vlen;
172
173 return 0;
174 }
175
tpm2_key_priv(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)176 int tpm2_key_priv(void *context, size_t hdrlen,
177 unsigned char tag,
178 const void *value, size_t vlen)
179 {
180 struct tpm2_key_context *ctx = context;
181
182 ctx->priv = value;
183 ctx->priv_len = vlen;
184
185 return 0;
186 }
187
188 /**
189 * tpm2_buf_append_auth() - append TPMS_AUTH_COMMAND to the buffer.
190 *
191 * @buf: an allocated tpm_buf instance
192 * @session_handle: session handle
193 * @nonce: the session nonce, may be NULL if not used
194 * @nonce_len: the session nonce length, may be 0 if not used
195 * @attributes: the session attributes
196 * @hmac: the session HMAC or password, may be NULL if not used
197 * @hmac_len: the session HMAC or password length, maybe 0 if not used
198 */
tpm2_buf_append_auth(struct tpm_buf * buf,u32 session_handle,const u8 * nonce,u16 nonce_len,u8 attributes,const u8 * hmac,u16 hmac_len)199 static void tpm2_buf_append_auth(struct tpm_buf *buf, u32 session_handle,
200 const u8 *nonce, u16 nonce_len,
201 u8 attributes,
202 const u8 *hmac, u16 hmac_len)
203 {
204 tpm_buf_append_u32(buf, 9 + nonce_len + hmac_len);
205 tpm_buf_append_u32(buf, session_handle);
206 tpm_buf_append_u16(buf, nonce_len);
207
208 if (nonce && nonce_len)
209 tpm_buf_append(buf, nonce, nonce_len);
210
211 tpm_buf_append_u8(buf, attributes);
212 tpm_buf_append_u16(buf, hmac_len);
213
214 if (hmac && hmac_len)
215 tpm_buf_append(buf, hmac, hmac_len);
216 }
217
218 /**
219 * tpm2_seal_trusted() - seal the payload of a trusted key
220 *
221 * @chip: TPM chip to use
222 * @payload: the key data in clear and encrypted form
223 * @options: authentication values and other options
224 *
225 * Return: < 0 on error and 0 on success.
226 */
tpm2_seal_trusted(struct tpm_chip * chip,struct trusted_key_payload * payload,struct trusted_key_options * options)227 int tpm2_seal_trusted(struct tpm_chip *chip,
228 struct trusted_key_payload *payload,
229 struct trusted_key_options *options)
230 {
231 int blob_len = 0;
232 struct tpm_buf buf;
233 u32 hash;
234 u32 flags;
235 int i;
236 int rc;
237
238 for (i = 0; i < ARRAY_SIZE(tpm2_hash_map); i++) {
239 if (options->hash == tpm2_hash_map[i].crypto_id) {
240 hash = tpm2_hash_map[i].tpm_id;
241 break;
242 }
243 }
244
245 if (i == ARRAY_SIZE(tpm2_hash_map))
246 return -EINVAL;
247
248 if (!options->keyhandle)
249 return -EINVAL;
250
251 rc = tpm_try_get_ops(chip);
252 if (rc)
253 return rc;
254
255 rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_CREATE);
256 if (rc) {
257 tpm_put_ops(chip);
258 return rc;
259 }
260
261 tpm_buf_append_u32(&buf, options->keyhandle);
262 tpm2_buf_append_auth(&buf, TPM2_RS_PW,
263 NULL /* nonce */, 0,
264 0 /* session_attributes */,
265 options->keyauth /* hmac */,
266 TPM_DIGEST_SIZE);
267
268 /* sensitive */
269 tpm_buf_append_u16(&buf, 4 + options->blobauth_len + payload->key_len);
270
271 tpm_buf_append_u16(&buf, options->blobauth_len);
272 if (options->blobauth_len)
273 tpm_buf_append(&buf, options->blobauth, options->blobauth_len);
274
275 tpm_buf_append_u16(&buf, payload->key_len);
276 tpm_buf_append(&buf, payload->key, payload->key_len);
277
278 /* public */
279 tpm_buf_append_u16(&buf, 14 + options->policydigest_len);
280 tpm_buf_append_u16(&buf, TPM_ALG_KEYEDHASH);
281 tpm_buf_append_u16(&buf, hash);
282
283 /* key properties */
284 flags = 0;
285 flags |= options->policydigest_len ? 0 : TPM2_OA_USER_WITH_AUTH;
286 flags |= payload->migratable ? 0 : (TPM2_OA_FIXED_TPM |
287 TPM2_OA_FIXED_PARENT);
288 tpm_buf_append_u32(&buf, flags);
289
290 /* policy */
291 tpm_buf_append_u16(&buf, options->policydigest_len);
292 if (options->policydigest_len)
293 tpm_buf_append(&buf, options->policydigest,
294 options->policydigest_len);
295
296 /* public parameters */
297 tpm_buf_append_u16(&buf, TPM_ALG_NULL);
298 tpm_buf_append_u16(&buf, 0);
299
300 /* outside info */
301 tpm_buf_append_u16(&buf, 0);
302
303 /* creation PCR */
304 tpm_buf_append_u32(&buf, 0);
305
306 if (buf.flags & TPM_BUF_OVERFLOW) {
307 rc = -E2BIG;
308 goto out;
309 }
310
311 rc = tpm_transmit_cmd(chip, &buf, 4, "sealing data");
312 if (rc)
313 goto out;
314
315 blob_len = be32_to_cpup((__be32 *) &buf.data[TPM_HEADER_SIZE]);
316 if (blob_len > MAX_BLOB_SIZE) {
317 rc = -E2BIG;
318 goto out;
319 }
320 if (tpm_buf_length(&buf) < TPM_HEADER_SIZE + 4 + blob_len) {
321 rc = -EFAULT;
322 goto out;
323 }
324
325 blob_len = tpm2_key_encode(payload, options,
326 &buf.data[TPM_HEADER_SIZE + 4],
327 blob_len);
328
329 out:
330 tpm_buf_destroy(&buf);
331
332 if (rc > 0) {
333 if (tpm2_rc_value(rc) == TPM2_RC_HASH)
334 rc = -EINVAL;
335 else
336 rc = -EPERM;
337 }
338 if (blob_len < 0)
339 rc = blob_len;
340 else
341 payload->blob_len = blob_len;
342
343 tpm_put_ops(chip);
344 return rc;
345 }
346
347 /**
348 * tpm2_load_cmd() - execute a TPM2_Load command
349 *
350 * @chip: TPM chip to use
351 * @payload: the key data in clear and encrypted form
352 * @options: authentication values and other options
353 * @blob_handle: returned blob handle
354 *
355 * Return: 0 on success.
356 * -E2BIG on wrong payload size.
357 * -EPERM on tpm error status.
358 * < 0 error from tpm_send.
359 */
tpm2_load_cmd(struct tpm_chip * chip,struct trusted_key_payload * payload,struct trusted_key_options * options,u32 * blob_handle)360 static int tpm2_load_cmd(struct tpm_chip *chip,
361 struct trusted_key_payload *payload,
362 struct trusted_key_options *options,
363 u32 *blob_handle)
364 {
365 struct tpm_buf buf;
366 unsigned int private_len;
367 unsigned int public_len;
368 unsigned int blob_len;
369 u8 *blob, *pub;
370 int rc;
371 u32 attrs;
372
373 rc = tpm2_key_decode(payload, options, &blob);
374 if (rc) {
375 /* old form */
376 blob = payload->blob;
377 payload->old_format = 1;
378 }
379
380 /* new format carries keyhandle but old format doesn't */
381 if (!options->keyhandle)
382 return -EINVAL;
383
384 /* must be big enough for at least the two be16 size counts */
385 if (payload->blob_len < 4)
386 return -EINVAL;
387
388 private_len = get_unaligned_be16(blob);
389
390 /* must be big enough for following public_len */
391 if (private_len + 2 + 2 > (payload->blob_len))
392 return -E2BIG;
393
394 public_len = get_unaligned_be16(blob + 2 + private_len);
395 if (private_len + 2 + public_len + 2 > payload->blob_len)
396 return -E2BIG;
397
398 pub = blob + 2 + private_len + 2;
399 /* key attributes are always at offset 4 */
400 attrs = get_unaligned_be32(pub + 4);
401
402 if ((attrs & (TPM2_OA_FIXED_TPM | TPM2_OA_FIXED_PARENT)) ==
403 (TPM2_OA_FIXED_TPM | TPM2_OA_FIXED_PARENT))
404 payload->migratable = 0;
405 else
406 payload->migratable = 1;
407
408 blob_len = private_len + public_len + 4;
409 if (blob_len > payload->blob_len)
410 return -E2BIG;
411
412 rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_LOAD);
413 if (rc)
414 return rc;
415
416 tpm_buf_append_u32(&buf, options->keyhandle);
417 tpm2_buf_append_auth(&buf, TPM2_RS_PW,
418 NULL /* nonce */, 0,
419 0 /* session_attributes */,
420 options->keyauth /* hmac */,
421 TPM_DIGEST_SIZE);
422
423 tpm_buf_append(&buf, blob, blob_len);
424
425 if (buf.flags & TPM_BUF_OVERFLOW) {
426 rc = -E2BIG;
427 goto out;
428 }
429
430 rc = tpm_transmit_cmd(chip, &buf, 4, "loading blob");
431 if (!rc)
432 *blob_handle = be32_to_cpup(
433 (__be32 *) &buf.data[TPM_HEADER_SIZE]);
434
435 out:
436 if (blob != payload->blob)
437 kfree(blob);
438 tpm_buf_destroy(&buf);
439
440 if (rc > 0)
441 rc = -EPERM;
442
443 return rc;
444 }
445
446 /**
447 * tpm2_unseal_cmd() - execute a TPM2_Unload command
448 *
449 * @chip: TPM chip to use
450 * @payload: the key data in clear and encrypted form
451 * @options: authentication values and other options
452 * @blob_handle: blob handle
453 *
454 * Return: 0 on success
455 * -EPERM on tpm error status
456 * < 0 error from tpm_send
457 */
tpm2_unseal_cmd(struct tpm_chip * chip,struct trusted_key_payload * payload,struct trusted_key_options * options,u32 blob_handle)458 static int tpm2_unseal_cmd(struct tpm_chip *chip,
459 struct trusted_key_payload *payload,
460 struct trusted_key_options *options,
461 u32 blob_handle)
462 {
463 struct tpm_buf buf;
464 u16 data_len;
465 u8 *data;
466 int rc;
467
468 rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_UNSEAL);
469 if (rc)
470 return rc;
471
472 tpm_buf_append_u32(&buf, blob_handle);
473 tpm2_buf_append_auth(&buf,
474 options->policyhandle ?
475 options->policyhandle : TPM2_RS_PW,
476 NULL /* nonce */, 0,
477 TPM2_SA_CONTINUE_SESSION,
478 options->blobauth /* hmac */,
479 options->blobauth_len);
480
481 rc = tpm_transmit_cmd(chip, &buf, 6, "unsealing");
482 if (rc > 0)
483 rc = -EPERM;
484
485 if (!rc) {
486 data_len = be16_to_cpup(
487 (__be16 *) &buf.data[TPM_HEADER_SIZE + 4]);
488 if (data_len < MIN_KEY_SIZE || data_len > MAX_KEY_SIZE) {
489 rc = -EFAULT;
490 goto out;
491 }
492
493 if (tpm_buf_length(&buf) < TPM_HEADER_SIZE + 6 + data_len) {
494 rc = -EFAULT;
495 goto out;
496 }
497 data = &buf.data[TPM_HEADER_SIZE + 6];
498
499 if (payload->old_format) {
500 /* migratable flag is at the end of the key */
501 memcpy(payload->key, data, data_len - 1);
502 payload->key_len = data_len - 1;
503 payload->migratable = data[data_len - 1];
504 } else {
505 /*
506 * migratable flag already collected from key
507 * attributes
508 */
509 memcpy(payload->key, data, data_len);
510 payload->key_len = data_len;
511 }
512 }
513
514 out:
515 tpm_buf_destroy(&buf);
516 return rc;
517 }
518
519 /**
520 * tpm2_unseal_trusted() - unseal the payload of a trusted key
521 *
522 * @chip: TPM chip to use
523 * @payload: the key data in clear and encrypted form
524 * @options: authentication values and other options
525 *
526 * Return: Same as with tpm_send.
527 */
tpm2_unseal_trusted(struct tpm_chip * chip,struct trusted_key_payload * payload,struct trusted_key_options * options)528 int tpm2_unseal_trusted(struct tpm_chip *chip,
529 struct trusted_key_payload *payload,
530 struct trusted_key_options *options)
531 {
532 u32 blob_handle;
533 int rc;
534
535 rc = tpm_try_get_ops(chip);
536 if (rc)
537 return rc;
538
539 rc = tpm2_load_cmd(chip, payload, options, &blob_handle);
540 if (rc)
541 goto out;
542
543 rc = tpm2_unseal_cmd(chip, payload, options, blob_handle);
544 tpm2_flush_context(chip, blob_handle);
545
546 out:
547 tpm_put_ops(chip);
548
549 return rc;
550 }
551
