1 /*
2 * Copyright 2016 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include <keymaster/km_openssl/attestation_record.h>
18
19 #include <assert.h>
20 #include <math.h>
21
22 #include <unordered_map>
23
24 #include <cppbor_parse.h>
25 #include <openssl/asn1t.h>
26
27 #include <keymaster/android_keymaster_utils.h>
28 #include <keymaster/attestation_context.h>
29 #include <keymaster/km_openssl/hmac.h>
30 #include <keymaster/km_openssl/openssl_err.h>
31 #include <keymaster/km_openssl/openssl_utils.h>
32
33 #define ASSERT_OR_RETURN_ERROR(stmt, error) \
34 do { \
35 assert(stmt); \
36 if (!(stmt)) { \
37 return error; \
38 } \
39 } while (0)
40
41 namespace keymaster {
42
43 constexpr size_t kMaximumAttestationChallengeLength = 128;
44
45 IMPLEMENT_ASN1_FUNCTIONS(KM_ROOT_OF_TRUST);
46 IMPLEMENT_ASN1_FUNCTIONS(KM_AUTH_LIST);
47 IMPLEMENT_ASN1_FUNCTIONS(KM_KEY_DESCRIPTION);
48
49 static const keymaster_tag_t kDeviceAttestationTags[] = {
50 KM_TAG_ATTESTATION_ID_BRAND, KM_TAG_ATTESTATION_ID_DEVICE,
51 KM_TAG_ATTESTATION_ID_PRODUCT, KM_TAG_ATTESTATION_ID_SERIAL,
52 KM_TAG_ATTESTATION_ID_IMEI, KM_TAG_ATTESTATION_ID_MEID,
53 KM_TAG_ATTESTATION_ID_MANUFACTURER, KM_TAG_ATTESTATION_ID_MODEL,
54 KM_TAG_ATTESTATION_ID_SECOND_IMEI};
55
56 struct KM_AUTH_LIST_Delete {
operator ()keymaster::KM_AUTH_LIST_Delete57 void operator()(KM_AUTH_LIST* p) { KM_AUTH_LIST_free(p); }
58 };
59
60 struct KM_KEY_DESCRIPTION_Delete {
operator ()keymaster::KM_KEY_DESCRIPTION_Delete61 void operator()(KM_KEY_DESCRIPTION* p) { KM_KEY_DESCRIPTION_free(p); }
62 };
63
64 struct KM_ROOT_OF_TRUST_Delete {
operator ()keymaster::KM_ROOT_OF_TRUST_Delete65 void operator()(KM_ROOT_OF_TRUST* p) { KM_ROOT_OF_TRUST_free(p); }
66 };
67
blob_to_bstr(const keymaster_blob_t & blob)68 static cppbor::Bstr blob_to_bstr(const keymaster_blob_t& blob) {
69 return cppbor::Bstr(std::pair(blob.data, blob.data_length));
70 }
71
bstr_to_blob(const cppbor::Bstr * bstr,keymaster_blob_t * blob)72 static keymaster_error_t bstr_to_blob(const cppbor::Bstr* bstr, keymaster_blob_t* blob) {
73 ASSERT_OR_RETURN_ERROR(bstr, KM_ERROR_INVALID_TAG);
74 const std::vector<uint8_t>& vec = bstr->value();
75 uint8_t* data = (uint8_t*)calloc(vec.size(), sizeof(uint8_t));
76 if (data == nullptr) {
77 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
78 }
79
80 std::copy(vec.begin(), vec.end(), data);
81 blob->data = data;
82 blob->data_length = vec.size();
83
84 return KM_ERROR_OK;
85 }
86
get_uint32_value(const keymaster_key_param_t & param)87 static uint32_t get_uint32_value(const keymaster_key_param_t& param) {
88 switch (keymaster_tag_get_type(param.tag)) {
89 case KM_ENUM:
90 case KM_ENUM_REP:
91 return param.enumerated;
92 case KM_UINT:
93 case KM_UINT_REP:
94 return param.integer;
95 default:
96 ASSERT_OR_RETURN_ERROR(false, 0xFFFFFFFF);
97 }
98 }
99
get_uint32_value(EatSecurityLevel level)100 static int64_t get_uint32_value(EatSecurityLevel level) {
101 return static_cast<int64_t>(level);
102 }
103
104 // Insert value in either the dest_integer or the dest_integer_set, whichever is provided.
insert_integer(ASN1_INTEGER * value,ASN1_INTEGER ** dest_integer,ASN1_INTEGER_SET ** dest_integer_set)105 static keymaster_error_t insert_integer(ASN1_INTEGER* value, ASN1_INTEGER** dest_integer,
106 ASN1_INTEGER_SET** dest_integer_set) {
107 ASSERT_OR_RETURN_ERROR((dest_integer == nullptr) ^ (dest_integer_set == nullptr),
108 KM_ERROR_UNEXPECTED_NULL_POINTER);
109 ASSERT_OR_RETURN_ERROR(value, KM_ERROR_INVALID_ARGUMENT);
110
111 if (dest_integer_set) {
112 if (!*dest_integer_set) {
113 *dest_integer_set = sk_ASN1_INTEGER_new_null();
114 }
115 if (!*dest_integer_set) {
116 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
117 }
118 if (!sk_ASN1_INTEGER_push(*dest_integer_set, value)) {
119 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
120 }
121 return KM_ERROR_OK;
122
123 } else if (dest_integer) {
124 if (*dest_integer) {
125 ASN1_INTEGER_free(*dest_integer);
126 }
127 *dest_integer = value;
128 return KM_ERROR_OK;
129 }
130
131 ASSERT_OR_RETURN_ERROR(false, KM_ERROR_UNKNOWN_ERROR); // Should never get here.
132 }
133
134 // Add a repeating enum to a map going mapping its key to list of values.
add_repeating_enum(EatClaim key,uint32_t value,std::unordered_map<EatClaim,cppbor::Array> * fields_map)135 static void add_repeating_enum(EatClaim key, uint32_t value,
136 std::unordered_map<EatClaim, cppbor::Array>* fields_map) {
137 auto field = fields_map->find(key);
138 if (field != fields_map->end()) {
139 field->second.add(value);
140 } else {
141 fields_map->insert({key, cppbor::Array().add(value)});
142 }
143 }
144
145 static keymaster_error_t
insert_unknown_tag(const keymaster_key_param_t & param,cppbor::Map * dest_map,std::unordered_map<EatClaim,cppbor::Array> * fields_map)146 insert_unknown_tag(const keymaster_key_param_t& param, cppbor::Map* dest_map,
147 std::unordered_map<EatClaim, cppbor::Array>* fields_map) {
148 EatClaim private_eat_tag = static_cast<EatClaim>(convert_to_eat_claim(param.tag));
149 switch (keymaster_tag_get_type(param.tag)) {
150 case KM_ENUM:
151 dest_map->add(private_eat_tag, param.enumerated);
152 break;
153 case KM_ENUM_REP:
154 add_repeating_enum(private_eat_tag, param.enumerated, fields_map);
155 break;
156 case KM_UINT:
157 dest_map->add(private_eat_tag, param.integer);
158 break;
159 case KM_UINT_REP:
160 add_repeating_enum(private_eat_tag, param.integer, fields_map);
161 break;
162 case KM_ULONG:
163 dest_map->add(private_eat_tag, param.long_integer);
164 break;
165 case KM_ULONG_REP:
166 add_repeating_enum(private_eat_tag, param.long_integer, fields_map);
167 break;
168 case KM_DATE:
169 dest_map->add(private_eat_tag, param.date_time);
170 break;
171 case KM_BOOL:
172 dest_map->add(private_eat_tag, true);
173 break;
174 case KM_BIGNUM:
175 case KM_BYTES:
176 dest_map->add(private_eat_tag, blob_to_bstr(param.blob));
177 break;
178 default:
179 ASSERT_OR_RETURN_ERROR(false, KM_ERROR_INVALID_TAG);
180 }
181 return KM_ERROR_OK;
182 }
183
184 /**
185 * Convert an IMEI encoded as a string of numbers into the UEID format defined in
186 * https://tools.ietf.org/html/draft-ietf-rats-eat.
187 * The resulting format is a bstr encoded as follows:
188 * - Type byte: 0x03
189 * - IMEI (without check digit), encoded as byte string of length 14 with each byte as the digit's
190 * value. The IMEI value encoded SHALL NOT include Luhn checksum or SVN information.
191 */
imei_to_ueid(const keymaster_blob_t & imei_blob,cppbor::Bstr * out)192 keymaster_error_t imei_to_ueid(const keymaster_blob_t& imei_blob, cppbor::Bstr* out) {
193 ASSERT_OR_RETURN_ERROR(imei_blob.data_length == kImeiBlobLength, KM_ERROR_INVALID_TAG);
194
195 uint8_t ueid[kUeidLength];
196 ueid[0] = kImeiTypeByte;
197 // imei_blob corresponds to android.telephony.TelephonyManager#getDeviceId(), which is the
198 // 15-digit IMEI (including the check digit), encoded as a string.
199 for (size_t i = 1; i < kUeidLength; i++) {
200 // Convert each character to its numeric value.
201 ueid[i] = imei_blob.data[i - 1] - '0'; // Intentionally skip check digit at last position.
202 }
203
204 *out = cppbor::Bstr(std::pair(ueid, sizeof(ueid)));
205 return KM_ERROR_OK;
206 }
207
ueid_to_imei_blob(const cppbor::Bstr * ueid,keymaster_blob_t * out)208 keymaster_error_t ueid_to_imei_blob(const cppbor::Bstr* ueid, keymaster_blob_t* out) {
209 ASSERT_OR_RETURN_ERROR(ueid, KM_ERROR_INVALID_TAG);
210 const std::vector<uint8_t>& ueid_vec = ueid->value();
211 ASSERT_OR_RETURN_ERROR(ueid_vec.size() == kUeidLength, KM_ERROR_INVALID_TAG);
212 ASSERT_OR_RETURN_ERROR(ueid_vec[0] == kImeiTypeByte, KM_ERROR_INVALID_TAG);
213
214 uint8_t* imei_string = (uint8_t*)calloc(kImeiBlobLength, sizeof(uint8_t));
215 // Fill string from left to right, and calculate Luhn check digit.
216 int luhn_digit_sum = 0;
217 for (size_t i = 0; i < kImeiBlobLength - 1; i++) {
218 uint8_t digit_i = ueid_vec[i + 1];
219 // Convert digit to its string value.
220 imei_string[i] = '0' + digit_i;
221 luhn_digit_sum += i % 2 == 0 ? digit_i : digit_i * 2 / 10 + (digit_i * 2) % 10;
222 }
223 imei_string[kImeiBlobLength - 1] = '0' + (10 - luhn_digit_sum % 10) % 10;
224
225 *out = {.data = imei_string, .data_length = kImeiBlobLength};
226 return KM_ERROR_OK;
227 }
228
ec_key_size_to_eat_curve(uint32_t key_size_bits,int * curve)229 keymaster_error_t ec_key_size_to_eat_curve(uint32_t key_size_bits, int* curve) {
230 switch (key_size_bits) {
231 default:
232 return KM_ERROR_UNSUPPORTED_KEY_SIZE;
233
234 case 224:
235 *curve = (int)EatEcCurve::P_224;
236 break;
237
238 case 256:
239 *curve = (int)EatEcCurve::P_256;
240 break;
241
242 case 384:
243 *curve = (int)EatEcCurve::P_384;
244 break;
245
246 case 521:
247 *curve = (int)EatEcCurve::P_521;
248 break;
249 }
250
251 return KM_ERROR_OK;
252 }
253
is_valid_attestation_challenge(const keymaster_blob_t & attestation_challenge)254 bool is_valid_attestation_challenge(const keymaster_blob_t& attestation_challenge) {
255 // TODO(171864369): Limit apps targeting >= API 30 to attestations in the range of
256 // [0, 128] bytes.
257 return (attestation_challenge.data_length <= kMaximumAttestationChallengeLength);
258 }
259
260 // Put the contents of the keymaster AuthorizationSet auth_list into the EAT record structure.
build_eat_submod(const AuthorizationSet & auth_list,const EatSecurityLevel security_level,cppbor::Map * submod)261 keymaster_error_t build_eat_submod(const AuthorizationSet& auth_list,
262 const EatSecurityLevel security_level, cppbor::Map* submod) {
263 ASSERT_OR_RETURN_ERROR(submod, KM_ERROR_UNEXPECTED_NULL_POINTER);
264
265 if (auth_list.empty()) return KM_ERROR_OK;
266
267 submod->add(EatClaim::SECURITY_LEVEL, get_uint32_value(security_level));
268
269 // Keep repeating fields in a separate map for easy lookup.
270 // Add them to submod map in postprocessing.
271 std::unordered_map<EatClaim, cppbor::Array> repeating_fields =
272 std::unordered_map<EatClaim, cppbor::Array>();
273
274 for (auto entry : auth_list) {
275
276 switch (entry.tag) {
277
278 default:
279 // Unknown tags should only be included if they're software-enforced.
280 if (security_level == EatSecurityLevel::UNRESTRICTED) {
281 keymaster_error_t error = insert_unknown_tag(entry, submod, &repeating_fields);
282 if (error != KM_ERROR_OK) {
283 return error;
284 }
285 }
286 break;
287
288 /* Tags ignored because they should never exist */
289 case KM_TAG_INVALID:
290
291 /* Tags ignored because they're not used. */
292 case KM_TAG_ALL_USERS:
293 case KM_TAG_EXPORTABLE:
294 case KM_TAG_ECIES_SINGLE_HASH_MODE:
295 case KM_TAG_KDF:
296
297 /* Tags ignored because they're used only to provide information to operations */
298 case KM_TAG_ASSOCIATED_DATA:
299 case KM_TAG_NONCE:
300 case KM_TAG_AUTH_TOKEN:
301 case KM_TAG_MAC_LENGTH:
302 case KM_TAG_ATTESTATION_CHALLENGE:
303 case KM_TAG_RESET_SINCE_ID_ROTATION:
304
305 /* Tags ignored because they have no meaning off-device */
306 case KM_TAG_USER_ID:
307 case KM_TAG_USER_SECURE_ID:
308 case KM_TAG_BLOB_USAGE_REQUIREMENTS:
309
310 /* Tags ignored because they're not usable by app keys */
311 case KM_TAG_BOOTLOADER_ONLY:
312 case KM_TAG_INCLUDE_UNIQUE_ID:
313 case KM_TAG_MAX_USES_PER_BOOT:
314 case KM_TAG_MIN_SECONDS_BETWEEN_OPS:
315 case KM_TAG_UNIQUE_ID:
316
317 /* Tags ignored because they contain data that should not be exported */
318 case KM_TAG_APPLICATION_DATA:
319 case KM_TAG_APPLICATION_ID:
320 case KM_TAG_ROOT_OF_TRUST:
321 continue;
322
323 /* Non-repeating enumerations */
324 case KM_TAG_ALGORITHM:
325 submod->add(EatClaim::ALGORITHM, get_uint32_value(entry));
326 break;
327 case KM_TAG_EC_CURVE:
328 submod->add(EatClaim::EC_CURVE, get_uint32_value(entry));
329 break;
330 case KM_TAG_USER_AUTH_TYPE:
331 submod->add(EatClaim::USER_AUTH_TYPE, get_uint32_value(entry));
332 break;
333 case KM_TAG_ORIGIN:
334 submod->add(EatClaim::ORIGIN, get_uint32_value(entry));
335 break;
336
337 /* Repeating enumerations */
338 case KM_TAG_PURPOSE:
339 add_repeating_enum(EatClaim::PURPOSE, get_uint32_value(entry), &repeating_fields);
340 break;
341 case KM_TAG_PADDING:
342 add_repeating_enum(EatClaim::PADDING, get_uint32_value(entry), &repeating_fields);
343 break;
344 case KM_TAG_DIGEST:
345 add_repeating_enum(EatClaim::DIGEST, get_uint32_value(entry), &repeating_fields);
346 break;
347 case KM_TAG_BLOCK_MODE:
348 add_repeating_enum(EatClaim::BLOCK_MODE, get_uint32_value(entry), &repeating_fields);
349 break;
350
351 /* Non-repeating unsigned integers */
352 case KM_TAG_KEY_SIZE:
353 submod->add(EatClaim::KEY_SIZE, get_uint32_value(entry));
354 break;
355 case KM_TAG_AUTH_TIMEOUT:
356 submod->add(EatClaim::AUTH_TIMEOUT, get_uint32_value(entry));
357 break;
358 case KM_TAG_OS_VERSION:
359 submod->add(EatClaim::OS_VERSION, get_uint32_value(entry));
360 break;
361 case KM_TAG_OS_PATCHLEVEL:
362 submod->add(EatClaim::OS_PATCHLEVEL, get_uint32_value(entry));
363 break;
364 case KM_TAG_VENDOR_PATCHLEVEL:
365 submod->add(EatClaim::VENDOR_PATCHLEVEL, get_uint32_value(entry));
366 break;
367 case KM_TAG_BOOT_PATCHLEVEL:
368 submod->add(EatClaim::BOOT_PATCHLEVEL, get_uint32_value(entry));
369 break;
370 case KM_TAG_MIN_MAC_LENGTH:
371 submod->add(EatClaim::MIN_MAC_LENGTH, get_uint32_value(entry));
372 break;
373
374 /* Non-repeating long unsigned integers */
375 case KM_TAG_RSA_PUBLIC_EXPONENT:
376 submod->add(EatClaim::RSA_PUBLIC_EXPONENT, entry.long_integer);
377 break;
378
379 /* Dates */
380 case KM_TAG_ACTIVE_DATETIME:
381 submod->add(EatClaim::ACTIVE_DATETIME, entry.date_time);
382 break;
383 case KM_TAG_ORIGINATION_EXPIRE_DATETIME:
384 submod->add(EatClaim::ORIGINATION_EXPIRE_DATETIME, entry.date_time);
385 break;
386 case KM_TAG_USAGE_EXPIRE_DATETIME:
387 submod->add(EatClaim::USAGE_EXPIRE_DATETIME, entry.date_time);
388 break;
389 case KM_TAG_CREATION_DATETIME:
390 submod->add(EatClaim::IAT, entry.date_time);
391 break;
392
393 /* Booleans */
394 case KM_TAG_NO_AUTH_REQUIRED:
395 submod->add(EatClaim::NO_AUTH_REQUIRED, true);
396 break;
397 case KM_TAG_ALL_APPLICATIONS:
398 submod->add(EatClaim::ALL_APPLICATIONS, true);
399 break;
400 case KM_TAG_ROLLBACK_RESISTANT:
401 submod->add(EatClaim::ROLLBACK_RESISTANT, true);
402 break;
403 case KM_TAG_ALLOW_WHILE_ON_BODY:
404 submod->add(EatClaim::ALLOW_WHILE_ON_BODY, true);
405 break;
406 case KM_TAG_UNLOCKED_DEVICE_REQUIRED:
407 submod->add(EatClaim::UNLOCKED_DEVICE_REQUIRED, true);
408 break;
409 case KM_TAG_CALLER_NONCE:
410 submod->add(EatClaim::CALLER_NONCE, true);
411 break;
412 case KM_TAG_TRUSTED_CONFIRMATION_REQUIRED:
413 submod->add(EatClaim::TRUSTED_CONFIRMATION_REQUIRED, true);
414 break;
415 case KM_TAG_EARLY_BOOT_ONLY:
416 submod->add(EatClaim::EARLY_BOOT_ONLY, true);
417 break;
418 case KM_TAG_DEVICE_UNIQUE_ATTESTATION:
419 submod->add(EatClaim::DEVICE_UNIQUE_ATTESTATION, true);
420 break;
421 case KM_TAG_IDENTITY_CREDENTIAL_KEY:
422 submod->add(EatClaim::IDENTITY_CREDENTIAL_KEY, true);
423 break;
424 case KM_TAG_TRUSTED_USER_PRESENCE_REQUIRED:
425 submod->add(EatClaim::TRUSTED_USER_PRESENCE_REQUIRED, true);
426 break;
427 case KM_TAG_STORAGE_KEY:
428 submod->add(EatClaim::STORAGE_KEY, true);
429 break;
430
431 /* Byte arrays*/
432 case KM_TAG_ATTESTATION_APPLICATION_ID:
433 submod->add(EatClaim::ATTESTATION_APPLICATION_ID, blob_to_bstr(entry.blob));
434 break;
435 case KM_TAG_ATTESTATION_ID_BRAND:
436 submod->add(EatClaim::ATTESTATION_ID_BRAND, blob_to_bstr(entry.blob));
437 break;
438 case KM_TAG_ATTESTATION_ID_DEVICE:
439 submod->add(EatClaim::ATTESTATION_ID_DEVICE, blob_to_bstr(entry.blob));
440 break;
441 case KM_TAG_ATTESTATION_ID_PRODUCT:
442 submod->add(EatClaim::ATTESTATION_ID_PRODUCT, blob_to_bstr(entry.blob));
443 break;
444 case KM_TAG_ATTESTATION_ID_SERIAL:
445 submod->add(EatClaim::ATTESTATION_ID_SERIAL, blob_to_bstr(entry.blob));
446 break;
447 case KM_TAG_ATTESTATION_ID_IMEI: {
448 cppbor::Bstr ueid("");
449 keymaster_error_t error = imei_to_ueid(entry.blob, &ueid);
450 if (error != KM_ERROR_OK) return error;
451 submod->add(EatClaim::UEID, ueid);
452 break;
453 }
454 case KM_TAG_ATTESTATION_ID_MEID:
455 submod->add(EatClaim::ATTESTATION_ID_MEID, blob_to_bstr(entry.blob));
456 break;
457 case KM_TAG_ATTESTATION_ID_MANUFACTURER:
458 submod->add(EatClaim::ATTESTATION_ID_MANUFACTURER, blob_to_bstr(entry.blob));
459 break;
460 case KM_TAG_ATTESTATION_ID_MODEL:
461 submod->add(EatClaim::ATTESTATION_ID_MODEL, blob_to_bstr(entry.blob));
462 break;
463 case KM_TAG_CONFIRMATION_TOKEN:
464 submod->add(EatClaim::CONFIRMATION_TOKEN, blob_to_bstr(entry.blob));
465 break;
466 }
467 }
468
469 // Move values from repeating enums into the submod map.
470 for (auto const& repeating_field : repeating_fields) {
471 EatClaim key = static_cast<EatClaim>(repeating_field.first);
472 submod->add(key, std::move(repeating_fields.at(key)));
473 }
474
475 int ec_curve;
476 uint32_t key_size;
477 if (auth_list.Contains(TAG_ALGORITHM, KM_ALGORITHM_EC) && !auth_list.Contains(TAG_EC_CURVE) &&
478 auth_list.GetTagValue(TAG_KEY_SIZE, &key_size)) {
479 // This must be a keymaster1 key. It's an EC key with no curve. Insert the curve.
480
481 keymaster_error_t error = ec_key_size_to_eat_curve(key_size, &ec_curve);
482 if (error != KM_ERROR_OK) return error;
483
484 submod->add(EatClaim::EC_CURVE, ec_curve);
485 }
486
487 return KM_ERROR_OK;
488 }
489
490 // Put the contents of the keymaster AuthorizationSet auth_list into the ASN.1 record structure,
491 // record.
build_auth_list(const AuthorizationSet & auth_list,KM_AUTH_LIST * record)492 keymaster_error_t build_auth_list(const AuthorizationSet& auth_list, KM_AUTH_LIST* record) {
493 ASSERT_OR_RETURN_ERROR(record, KM_ERROR_UNEXPECTED_NULL_POINTER);
494
495 if (auth_list.empty()) return KM_ERROR_OK;
496
497 for (auto entry : auth_list) {
498
499 ASN1_INTEGER_SET** integer_set = nullptr;
500 ASN1_INTEGER** integer_ptr = nullptr;
501 ASN1_OCTET_STRING** string_ptr = nullptr;
502 ASN1_NULL** bool_ptr = nullptr;
503
504 switch (entry.tag) {
505
506 /* Tags ignored because they should never exist */
507 case KM_TAG_INVALID:
508
509 /* Tags ignored because they're not used. */
510 case KM_TAG_ALL_USERS:
511 case KM_TAG_EXPORTABLE:
512 case KM_TAG_ECIES_SINGLE_HASH_MODE:
513
514 /* Tags ignored because they're used only to provide information to operations */
515 case KM_TAG_ASSOCIATED_DATA:
516 case KM_TAG_NONCE:
517 case KM_TAG_AUTH_TOKEN:
518 case KM_TAG_MAC_LENGTH:
519 case KM_TAG_ATTESTATION_CHALLENGE:
520 case KM_TAG_KDF:
521
522 /* Tags ignored because they're used only to provide for certificate generation */
523 case KM_TAG_CERTIFICATE_SERIAL:
524 case KM_TAG_CERTIFICATE_SUBJECT:
525 case KM_TAG_CERTIFICATE_NOT_BEFORE:
526 case KM_TAG_CERTIFICATE_NOT_AFTER:
527 case KM_TAG_INCLUDE_UNIQUE_ID:
528 case KM_TAG_RESET_SINCE_ID_ROTATION:
529
530 /* Tags ignored because they have no meaning off-device */
531 case KM_TAG_USER_ID:
532 case KM_TAG_USER_SECURE_ID:
533 case KM_TAG_BLOB_USAGE_REQUIREMENTS:
534
535 /* Tags ignored because they're not usable by app keys */
536 case KM_TAG_BOOTLOADER_ONLY:
537 case KM_TAG_MAX_BOOT_LEVEL:
538 case KM_TAG_MAX_USES_PER_BOOT:
539 case KM_TAG_MIN_SECONDS_BETWEEN_OPS:
540 case KM_TAG_STORAGE_KEY:
541 case KM_TAG_UNIQUE_ID:
542
543 /* Tags ignored because they contain data that should not be exported */
544 case KM_TAG_APPLICATION_DATA:
545 case KM_TAG_APPLICATION_ID:
546 case KM_TAG_CONFIRMATION_TOKEN:
547 case KM_TAG_ROOT_OF_TRUST:
548 continue;
549
550 /* Non-repeating enumerations */
551 case KM_TAG_ALGORITHM:
552 integer_ptr = &record->algorithm;
553 break;
554 case KM_TAG_EC_CURVE:
555 integer_ptr = &record->ec_curve;
556 break;
557 case KM_TAG_USER_AUTH_TYPE:
558 integer_ptr = &record->user_auth_type;
559 break;
560 case KM_TAG_ORIGIN:
561 integer_ptr = &record->origin;
562 break;
563
564 /* Repeating enumerations */
565 case KM_TAG_PURPOSE:
566 integer_set = &record->purpose;
567 break;
568 case KM_TAG_PADDING:
569 integer_set = &record->padding;
570 break;
571 case KM_TAG_DIGEST:
572 integer_set = &record->digest;
573 break;
574 case KM_TAG_BLOCK_MODE:
575 integer_set = &record->block_mode;
576 break;
577 case KM_TAG_RSA_OAEP_MGF_DIGEST:
578 integer_set = &record->mgf_digest;
579 break;
580
581 /* Non-repeating unsigned integers */
582 case KM_TAG_KEY_SIZE:
583 integer_ptr = &record->key_size;
584 break;
585 case KM_TAG_AUTH_TIMEOUT:
586 integer_ptr = &record->auth_timeout;
587 break;
588 case KM_TAG_OS_VERSION:
589 integer_ptr = &record->os_version;
590 break;
591 case KM_TAG_OS_PATCHLEVEL:
592 integer_ptr = &record->os_patchlevel;
593 break;
594 case KM_TAG_MIN_MAC_LENGTH:
595 integer_ptr = &record->min_mac_length;
596 break;
597 case KM_TAG_BOOT_PATCHLEVEL:
598 integer_ptr = &record->boot_patch_level;
599 break;
600 case KM_TAG_VENDOR_PATCHLEVEL:
601 integer_ptr = &record->vendor_patchlevel;
602 break;
603 case KM_TAG_USAGE_COUNT_LIMIT:
604 integer_ptr = &record->usage_count_limit;
605 break;
606
607 /* Non-repeating long unsigned integers */
608 case KM_TAG_RSA_PUBLIC_EXPONENT:
609 integer_ptr = &record->rsa_public_exponent;
610 break;
611
612 /* Dates */
613 case KM_TAG_ACTIVE_DATETIME:
614 integer_ptr = &record->active_date_time;
615 break;
616 case KM_TAG_ORIGINATION_EXPIRE_DATETIME:
617 integer_ptr = &record->origination_expire_date_time;
618 break;
619 case KM_TAG_USAGE_EXPIRE_DATETIME:
620 integer_ptr = &record->usage_expire_date_time;
621 break;
622 case KM_TAG_CREATION_DATETIME:
623 integer_ptr = &record->creation_date_time;
624 break;
625
626 /* Booleans */
627 case KM_TAG_NO_AUTH_REQUIRED:
628 bool_ptr = &record->no_auth_required;
629 break;
630 case KM_TAG_ALL_APPLICATIONS:
631 bool_ptr = &record->all_applications;
632 break;
633 case KM_TAG_ROLLBACK_RESISTANT:
634 bool_ptr = &record->rollback_resistant;
635 break;
636 case KM_TAG_ROLLBACK_RESISTANCE:
637 bool_ptr = &record->rollback_resistance;
638 break;
639 case KM_TAG_ALLOW_WHILE_ON_BODY:
640 bool_ptr = &record->allow_while_on_body;
641 break;
642 case KM_TAG_UNLOCKED_DEVICE_REQUIRED:
643 bool_ptr = &record->unlocked_device_required;
644 break;
645 case KM_TAG_CALLER_NONCE:
646 bool_ptr = &record->caller_nonce;
647 break;
648 case KM_TAG_TRUSTED_CONFIRMATION_REQUIRED:
649 bool_ptr = &record->trusted_confirmation_required;
650 break;
651 case KM_TAG_EARLY_BOOT_ONLY:
652 bool_ptr = &record->early_boot_only;
653 break;
654 case KM_TAG_DEVICE_UNIQUE_ATTESTATION:
655 bool_ptr = &record->device_unique_attestation;
656 break;
657 case KM_TAG_IDENTITY_CREDENTIAL_KEY:
658 bool_ptr = &record->identity_credential_key;
659 break;
660 case KM_TAG_TRUSTED_USER_PRESENCE_REQUIRED:
661 bool_ptr = &record->trusted_user_presence_required;
662 break;
663
664 /* Byte arrays*/
665 case KM_TAG_ATTESTATION_APPLICATION_ID:
666 string_ptr = &record->attestation_application_id;
667 break;
668 case KM_TAG_ATTESTATION_ID_BRAND:
669 string_ptr = &record->attestation_id_brand;
670 break;
671 case KM_TAG_ATTESTATION_ID_DEVICE:
672 string_ptr = &record->attestation_id_device;
673 break;
674 case KM_TAG_ATTESTATION_ID_PRODUCT:
675 string_ptr = &record->attestation_id_product;
676 break;
677 case KM_TAG_ATTESTATION_ID_SERIAL:
678 string_ptr = &record->attestation_id_serial;
679 break;
680 case KM_TAG_ATTESTATION_ID_IMEI:
681 string_ptr = &record->attestation_id_imei;
682 break;
683 case KM_TAG_ATTESTATION_ID_SECOND_IMEI:
684 string_ptr = &record->attestation_id_second_imei;
685 break;
686 case KM_TAG_ATTESTATION_ID_MEID:
687 string_ptr = &record->attestation_id_meid;
688 break;
689 case KM_TAG_ATTESTATION_ID_MANUFACTURER:
690 string_ptr = &record->attestation_id_manufacturer;
691 break;
692 case KM_TAG_ATTESTATION_ID_MODEL:
693 string_ptr = &record->attestation_id_model;
694 break;
695 case KM_TAG_MODULE_HASH:
696 string_ptr = &record->module_hash;
697 break;
698 }
699
700 keymaster_tag_type_t type = keymaster_tag_get_type(entry.tag);
701 switch (type) {
702 case KM_ENUM:
703 case KM_ENUM_REP:
704 case KM_UINT:
705 case KM_UINT_REP: {
706 ASSERT_OR_RETURN_ERROR((keymaster_tag_repeatable(entry.tag) && integer_set) ||
707 (!keymaster_tag_repeatable(entry.tag) && integer_ptr),
708 KM_ERROR_INVALID_TAG);
709
710 UniquePtr<ASN1_INTEGER, ASN1_INTEGER_Delete> value(ASN1_INTEGER_new());
711 if (!value.get()) {
712 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
713 }
714 if (!ASN1_INTEGER_set(value.get(), get_uint32_value(entry))) {
715 return TranslateLastOpenSslError();
716 }
717
718 insert_integer(value.release(), integer_ptr, integer_set);
719 break;
720 }
721
722 case KM_ULONG:
723 case KM_ULONG_REP:
724 case KM_DATE: {
725 ASSERT_OR_RETURN_ERROR((keymaster_tag_repeatable(entry.tag) && integer_set) ||
726 (!keymaster_tag_repeatable(entry.tag) && integer_ptr),
727 KM_ERROR_INVALID_TAG);
728
729 UniquePtr<BIGNUM, BIGNUM_Delete> bn_value(BN_new());
730 if (!bn_value.get()) {
731 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
732 }
733
734 if (type == KM_DATE) {
735 if (!BN_set_u64(bn_value.get(), entry.date_time)) {
736 return TranslateLastOpenSslError();
737 }
738 } else {
739 if (!BN_set_u64(bn_value.get(), entry.long_integer)) {
740 return TranslateLastOpenSslError();
741 }
742 }
743
744 UniquePtr<ASN1_INTEGER, ASN1_INTEGER_Delete> value(
745 BN_to_ASN1_INTEGER(bn_value.get(), nullptr));
746 if (!value.get()) {
747 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
748 }
749
750 insert_integer(value.release(), integer_ptr, integer_set);
751 break;
752 }
753
754 case KM_BOOL:
755 ASSERT_OR_RETURN_ERROR(bool_ptr, KM_ERROR_INVALID_TAG);
756 if (!*bool_ptr) *bool_ptr = ASN1_NULL_new();
757 if (!*bool_ptr) return KM_ERROR_MEMORY_ALLOCATION_FAILED;
758 break;
759
760 /* Byte arrays*/
761 case KM_BYTES:
762 ASSERT_OR_RETURN_ERROR(string_ptr, KM_ERROR_INVALID_TAG);
763 if (!*string_ptr) {
764 *string_ptr = ASN1_OCTET_STRING_new();
765 }
766 if (!*string_ptr) {
767 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
768 }
769 if (!ASN1_OCTET_STRING_set(*string_ptr, entry.blob.data, entry.blob.data_length)) {
770 return TranslateLastOpenSslError();
771 }
772 break;
773
774 default:
775 return KM_ERROR_UNIMPLEMENTED;
776 }
777 }
778
779 keymaster_ec_curve_t ec_curve;
780 uint32_t key_size;
781 if (auth_list.Contains(TAG_ALGORITHM, KM_ALGORITHM_EC) && //
782 !auth_list.Contains(TAG_EC_CURVE) && //
783 auth_list.GetTagValue(TAG_KEY_SIZE, &key_size)) {
784 // This must be a keymaster1 key. It's an EC key with no curve. Insert the curve if we
785 // can unambiguously figure it out.
786
787 keymaster_error_t error = EcKeySizeToCurve(key_size, &ec_curve);
788 if (error != KM_ERROR_OK) return error;
789
790 UniquePtr<ASN1_INTEGER, ASN1_INTEGER_Delete> value(ASN1_INTEGER_new());
791 if (!value.get()) {
792 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
793 }
794
795 if (!ASN1_INTEGER_set(value.get(), ec_curve)) {
796 return TranslateLastOpenSslError();
797 }
798
799 insert_integer(value.release(), &record->ec_curve, nullptr);
800 }
801
802 return KM_ERROR_OK;
803 }
804
805 // Construct a CBOR-encoded attestation record containing the values from sw_enforced
806 // and tee_enforced.
build_eat_record(const AuthorizationSet & attestation_params,AuthorizationSet sw_enforced,AuthorizationSet tee_enforced,const AttestationContext & context,std::vector<uint8_t> * eat_token)807 keymaster_error_t build_eat_record(const AuthorizationSet& attestation_params,
808 AuthorizationSet sw_enforced, AuthorizationSet tee_enforced,
809 const AttestationContext& context,
810 std::vector<uint8_t>* eat_token) {
811 ASSERT_OR_RETURN_ERROR(eat_token, KM_ERROR_UNEXPECTED_NULL_POINTER);
812
813 cppbor::Map eat_record;
814 switch (context.GetSecurityLevel()) {
815 case KM_SECURITY_LEVEL_SOFTWARE:
816 eat_record.add(EatClaim::SECURITY_LEVEL, get_uint32_value(EatSecurityLevel::UNRESTRICTED));
817 break;
818 case KM_SECURITY_LEVEL_TRUSTED_ENVIRONMENT:
819 eat_record.add(EatClaim::SECURITY_LEVEL,
820 get_uint32_value(EatSecurityLevel::SECURE_RESTRICTED));
821 break;
822 case KM_SECURITY_LEVEL_STRONGBOX:
823 eat_record.add(EatClaim::SECURITY_LEVEL, get_uint32_value(EatSecurityLevel::HARDWARE));
824 break;
825 default:
826 return KM_ERROR_UNKNOWN_ERROR;
827 }
828
829 keymaster_error_t error;
830 const AttestationContext::VerifiedBootParams* vb_params = context.GetVerifiedBootParams(&error);
831 if (error != KM_ERROR_OK) return error;
832
833 if (vb_params->verified_boot_key.data_length) {
834 eat_record.add(EatClaim::VERIFIED_BOOT_KEY, blob_to_bstr(vb_params->verified_boot_key));
835 }
836 if (vb_params->verified_boot_hash.data_length) {
837 eat_record.add(EatClaim::VERIFIED_BOOT_HASH, blob_to_bstr(vb_params->verified_boot_hash));
838 }
839 if (vb_params->device_locked) {
840 eat_record.add(EatClaim::DEVICE_LOCKED, vb_params->device_locked);
841 }
842
843 bool verified_or_self_signed = (vb_params->verified_boot_state == KM_VERIFIED_BOOT_VERIFIED ||
844 vb_params->verified_boot_state == KM_VERIFIED_BOOT_SELF_SIGNED);
845 auto eat_boot_state = cppbor::Array()
846 .add(verified_or_self_signed) // secure-boot-enabled
847 .add(verified_or_self_signed) // debug-disabled
848 .add(verified_or_self_signed) // debug-disabled-since-boot
849 .add(verified_or_self_signed) // debug-permanent-disable
850 .add(false); // debug-full-permanent-disable (no way to verify)
851 eat_record.add(EatClaim::BOOT_STATE, std::move(eat_boot_state));
852 eat_record.add(EatClaim::OFFICIAL_BUILD,
853 vb_params->verified_boot_state == KM_VERIFIED_BOOT_VERIFIED);
854
855 eat_record.add(EatClaim::ATTESTATION_VERSION,
856 version_to_attestation_version(context.GetKmVersion()));
857 eat_record.add(EatClaim::KEYMASTER_VERSION,
858 version_to_attestation_km_version(context.GetKmVersion()));
859
860 keymaster_blob_t attestation_challenge = {nullptr, 0};
861 if (!attestation_params.GetTagValue(TAG_ATTESTATION_CHALLENGE, &attestation_challenge)) {
862 return KM_ERROR_ATTESTATION_CHALLENGE_MISSING;
863 }
864
865 if (!is_valid_attestation_challenge(attestation_challenge)) {
866 return KM_ERROR_INVALID_INPUT_LENGTH;
867 }
868
869 eat_record.add(EatClaim::NONCE, blob_to_bstr(attestation_challenge));
870
871 keymaster_blob_t attestation_app_id;
872 if (!attestation_params.GetTagValue(TAG_ATTESTATION_APPLICATION_ID, &attestation_app_id)) {
873 return KM_ERROR_ATTESTATION_APPLICATION_ID_MISSING;
874 }
875 // TODO: what should happen when sw_enforced already contains TAG_ATTESTATION_APPLICATION_ID?
876 // (as is the case in android_keymaster_test.cpp). For now, we will ignore the provided one in
877 // attestation_params if that's the case.
878 keymaster_blob_t existing_app_id;
879 if (!sw_enforced.GetTagValue(TAG_ATTESTATION_APPLICATION_ID, &existing_app_id)) {
880 sw_enforced.push_back(TAG_ATTESTATION_APPLICATION_ID, attestation_app_id);
881 }
882
883 error = context.VerifyAndCopyDeviceIds(
884 attestation_params,
885 context.GetSecurityLevel() == KM_SECURITY_LEVEL_SOFTWARE ? &sw_enforced : &tee_enforced);
886 if (error == KM_ERROR_UNIMPLEMENTED) {
887 // The KeymasterContext implementation does not support device ID attestation. Bail out if
888 // device ID attestation is being attempted.
889 for (const auto& tag : kDeviceAttestationTags) {
890 if (attestation_params.find(tag) != -1) {
891 return KM_ERROR_CANNOT_ATTEST_IDS;
892 }
893 }
894 } else if (error != KM_ERROR_OK) {
895 return error;
896 }
897
898 if (attestation_params.Contains(TAG_DEVICE_UNIQUE_ATTESTATION) &&
899 context.GetSecurityLevel() == KM_SECURITY_LEVEL_STRONGBOX) {
900 eat_record.add(EatClaim::DEVICE_UNIQUE_ATTESTATION, true);
901 }
902
903 cppbor::Map software_submod;
904 error = build_eat_submod(sw_enforced, EatSecurityLevel::UNRESTRICTED, &software_submod);
905 if (error != KM_ERROR_OK) return error;
906
907 cppbor::Map tee_submod;
908 error = build_eat_submod(tee_enforced, EatSecurityLevel::SECURE_RESTRICTED, &tee_submod);
909 if (error != KM_ERROR_OK) return error;
910
911 if (software_submod.size() + tee_submod.size() > 0) {
912 cppbor::Map submods;
913 if (software_submod.size() > 0) {
914 submods.add(kEatSubmodNameSoftware, std::move(software_submod));
915 }
916 if (tee_submod.size() > 0) {
917 submods.add(kEatSubmodNameTee, std::move(tee_submod));
918 }
919
920 eat_record.add(EatClaim::SUBMODS, std::move(submods));
921 }
922
923 if (attestation_params.GetTagValue(TAG_INCLUDE_UNIQUE_ID)) {
924 uint64_t creation_datetime;
925 // Only check sw_enforced for TAG_CREATION_DATETIME, since it shouldn't be in tee_enforced,
926 // since this implementation has no secure wall clock.
927 if (!sw_enforced.GetTagValue(TAG_CREATION_DATETIME, &creation_datetime)) {
928 LOG_E("Unique ID cannot be created without creation datetime");
929 return KM_ERROR_INVALID_KEY_BLOB;
930 }
931
932 Buffer unique_id = context.GenerateUniqueId(
933 creation_datetime, attestation_app_id,
934 attestation_params.GetTagValue(TAG_RESET_SINCE_ID_ROTATION), &error);
935 if (error != KM_ERROR_OK) return error;
936
937 eat_record.add(EatClaim::CTI,
938 cppbor::Bstr(std::pair(unique_id.begin(), unique_id.available_read())));
939 }
940
941 *eat_token = eat_record.encode();
942
943 return KM_ERROR_OK;
944 }
945
build_unique_id_input(uint64_t creation_date_time,const keymaster_blob_t & application_id,bool reset_since_rotation,Buffer * input_data)946 keymaster_error_t build_unique_id_input(uint64_t creation_date_time,
947 const keymaster_blob_t& application_id,
948 bool reset_since_rotation, Buffer* input_data) {
949 if (input_data == nullptr) {
950 return KM_ERROR_UNEXPECTED_NULL_POINTER;
951 }
952 uint64_t rounded_date = creation_date_time / 2592000000LLU;
953 uint8_t* serialized_date = reinterpret_cast<uint8_t*>(&rounded_date);
954 uint8_t reset_byte = (reset_since_rotation ? 1 : 0);
955
956 if (!input_data->Reinitialize(sizeof(rounded_date) + application_id.data_length + 1) ||
957 !input_data->write(serialized_date, sizeof(rounded_date)) ||
958 !input_data->write(application_id.data, application_id.data_length) ||
959 !input_data->write(&reset_byte, 1)) {
960 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
961 }
962 return KM_ERROR_OK;
963 }
964
generate_unique_id(const std::vector<uint8_t> & hbk,uint64_t creation_date_time,const keymaster_blob_t & application_id,bool reset_since_rotation,Buffer * unique_id)965 keymaster_error_t generate_unique_id(const std::vector<uint8_t>& hbk, uint64_t creation_date_time,
966 const keymaster_blob_t& application_id,
967 bool reset_since_rotation, Buffer* unique_id) {
968 if (unique_id == nullptr) {
969 return KM_ERROR_UNEXPECTED_NULL_POINTER;
970 }
971 HmacSha256 hmac;
972 hmac.Init(hbk.data(), hbk.size());
973
974 Buffer input;
975 keymaster_error_t error =
976 build_unique_id_input(creation_date_time, application_id, reset_since_rotation, &input);
977 if (error != KM_ERROR_OK) {
978 return error;
979 }
980 if (!unique_id->Reinitialize(UNIQUE_ID_SIZE)) {
981 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
982 }
983 hmac.Sign(input.peek_read(), input.available_read(), unique_id->peek_write(),
984 unique_id->available_write());
985 unique_id->advance_write(UNIQUE_ID_SIZE);
986 return KM_ERROR_OK;
987 }
988
989 // Construct an ASN1.1 DER-encoded attestation record containing the values from sw_enforced and
990 // tee_enforced.
build_attestation_record(const AuthorizationSet & attestation_params,AuthorizationSet sw_enforced,AuthorizationSet tee_enforced,const AttestationContext & context,UniquePtr<uint8_t[]> * asn1_key_desc,size_t * asn1_key_desc_len)991 keymaster_error_t build_attestation_record(const AuthorizationSet& attestation_params, //
992 AuthorizationSet sw_enforced,
993 AuthorizationSet tee_enforced,
994 const AttestationContext& context,
995 UniquePtr<uint8_t[]>* asn1_key_desc,
996 size_t* asn1_key_desc_len) {
997 ASSERT_OR_RETURN_ERROR(asn1_key_desc && asn1_key_desc_len, KM_ERROR_UNEXPECTED_NULL_POINTER);
998
999 UniquePtr<KM_KEY_DESCRIPTION, KM_KEY_DESCRIPTION_Delete> key_desc(KM_KEY_DESCRIPTION_new());
1000 if (!key_desc.get()) return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1001
1002 KM_ROOT_OF_TRUST* root_of_trust = nullptr;
1003 if (context.GetSecurityLevel() == KM_SECURITY_LEVEL_SOFTWARE) {
1004 key_desc->software_enforced->root_of_trust = KM_ROOT_OF_TRUST_new();
1005 root_of_trust = key_desc->software_enforced->root_of_trust;
1006 } else {
1007 key_desc->tee_enforced->root_of_trust = KM_ROOT_OF_TRUST_new();
1008 root_of_trust = key_desc->tee_enforced->root_of_trust;
1009 }
1010
1011 keymaster_error_t error;
1012 auto vb_params = context.GetVerifiedBootParams(&error);
1013 if (error != KM_ERROR_OK) return error;
1014 if (vb_params->verified_boot_key.data_length &&
1015 !ASN1_OCTET_STRING_set(root_of_trust->verified_boot_key, vb_params->verified_boot_key.data,
1016 vb_params->verified_boot_key.data_length)) {
1017 return TranslateLastOpenSslError();
1018 }
1019 if (vb_params->verified_boot_hash.data_length &&
1020 !ASN1_OCTET_STRING_set(root_of_trust->verified_boot_hash,
1021 vb_params->verified_boot_hash.data,
1022 vb_params->verified_boot_hash.data_length)) {
1023 return TranslateLastOpenSslError();
1024 }
1025
1026 root_of_trust->device_locked = vb_params->device_locked ? 0xFF : 0x00;
1027 if (!ASN1_ENUMERATED_set(root_of_trust->verified_boot_state, vb_params->verified_boot_state)) {
1028 return TranslateLastOpenSslError();
1029 }
1030
1031 if (!ASN1_INTEGER_set(key_desc->attestation_version,
1032 version_to_attestation_version(context.GetKmVersion())) ||
1033 !ASN1_ENUMERATED_set(key_desc->attestation_security_level, context.GetSecurityLevel()) ||
1034 !ASN1_INTEGER_set(key_desc->keymaster_version,
1035 version_to_attestation_km_version(context.GetKmVersion())) ||
1036 !ASN1_ENUMERATED_set(key_desc->keymaster_security_level, context.GetSecurityLevel())) {
1037 return TranslateLastOpenSslError();
1038 }
1039
1040 keymaster_blob_t attestation_challenge = {nullptr, 0};
1041 if (!attestation_params.GetTagValue(TAG_ATTESTATION_CHALLENGE, &attestation_challenge)) {
1042 return KM_ERROR_ATTESTATION_CHALLENGE_MISSING;
1043 }
1044
1045 if (!is_valid_attestation_challenge(attestation_challenge)) {
1046 return KM_ERROR_INVALID_INPUT_LENGTH;
1047 }
1048
1049 if (!ASN1_OCTET_STRING_set(key_desc->attestation_challenge, attestation_challenge.data,
1050 attestation_challenge.data_length)) {
1051 return TranslateLastOpenSslError();
1052 }
1053
1054 keymaster_blob_t attestation_app_id;
1055 if (!attestation_params.GetTagValue(TAG_ATTESTATION_APPLICATION_ID, &attestation_app_id)) {
1056 return KM_ERROR_ATTESTATION_APPLICATION_ID_MISSING;
1057 }
1058 sw_enforced.push_back(TAG_ATTESTATION_APPLICATION_ID, attestation_app_id);
1059
1060 error = context.VerifyAndCopyDeviceIds(
1061 attestation_params,
1062 context.GetSecurityLevel() == KM_SECURITY_LEVEL_SOFTWARE ? &sw_enforced : &tee_enforced);
1063 if (error == KM_ERROR_UNIMPLEMENTED) {
1064 // The KeymasterContext implementation does not support device ID attestation. Bail out if
1065 // device ID attestation is being attempted.
1066 for (const auto& tag : kDeviceAttestationTags) {
1067 if (attestation_params.find(tag) != -1) {
1068 return KM_ERROR_CANNOT_ATTEST_IDS;
1069 }
1070 }
1071 } else if (error != KM_ERROR_OK) {
1072 return error;
1073 }
1074
1075 if (attestation_params.Contains(TAG_DEVICE_UNIQUE_ATTESTATION) &&
1076 context.GetSecurityLevel() == KM_SECURITY_LEVEL_STRONGBOX) {
1077 tee_enforced.push_back(TAG_DEVICE_UNIQUE_ATTESTATION);
1078 };
1079
1080 error = build_auth_list(sw_enforced, key_desc->software_enforced);
1081 if (error != KM_ERROR_OK) return error;
1082
1083 error = build_auth_list(tee_enforced, key_desc->tee_enforced);
1084 if (error != KM_ERROR_OK) return error;
1085
1086 if (attestation_params.GetTagValue(TAG_INCLUDE_UNIQUE_ID)) {
1087 uint64_t creation_datetime;
1088 // Only check sw_enforced for TAG_CREATION_DATETIME, since it shouldn't be in tee_enforced,
1089 // since this implementation has no secure wall clock.
1090 if (!sw_enforced.GetTagValue(TAG_CREATION_DATETIME, &creation_datetime)) {
1091 LOG_E("Unique ID cannot be created without creation datetime");
1092 return KM_ERROR_INVALID_KEY_BLOB;
1093 }
1094
1095 Buffer unique_id = context.GenerateUniqueId(
1096 creation_datetime, attestation_app_id,
1097 attestation_params.GetTagValue(TAG_RESET_SINCE_ID_ROTATION), &error);
1098 if (error != KM_ERROR_OK) return error;
1099
1100 if (!ASN1_OCTET_STRING_set(key_desc->unique_id, unique_id.peek_read(),
1101 unique_id.available_read()))
1102 return TranslateLastOpenSslError();
1103 }
1104
1105 int len = i2d_KM_KEY_DESCRIPTION(key_desc.get(), nullptr);
1106 if (len < 0) return TranslateLastOpenSslError();
1107 *asn1_key_desc_len = len;
1108 asn1_key_desc->reset(new (std::nothrow) uint8_t[*asn1_key_desc_len]);
1109 if (!asn1_key_desc->get()) return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1110 uint8_t* p = asn1_key_desc->get();
1111 len = i2d_KM_KEY_DESCRIPTION(key_desc.get(), &p);
1112 if (len < 0) return TranslateLastOpenSslError();
1113
1114 return KM_ERROR_OK;
1115 }
1116
1117 // Copy all enumerated values with the specified tag from stack to auth_list.
get_repeated_enums(const ASN1_INTEGER_SET * stack,keymaster_tag_t tag,AuthorizationSet * auth_list)1118 static bool get_repeated_enums(const ASN1_INTEGER_SET* stack, keymaster_tag_t tag,
1119 AuthorizationSet* auth_list) {
1120 ASSERT_OR_RETURN_ERROR(keymaster_tag_get_type(tag) == KM_ENUM_REP, KM_ERROR_INVALID_TAG);
1121 for (size_t i = 0; i < sk_ASN1_INTEGER_num(stack); ++i) {
1122 if (!auth_list->push_back(
1123 keymaster_param_enum(tag, ASN1_INTEGER_get(sk_ASN1_INTEGER_value(stack, i)))))
1124 return false;
1125 }
1126 return true;
1127 }
1128
1129 // Add the specified integer tag/value pair to auth_list.
1130 template <keymaster_tag_type_t Type, keymaster_tag_t Tag, typename KeymasterEnum>
get_enum(const ASN1_INTEGER * asn1_int,TypedEnumTag<Type,Tag,KeymasterEnum> tag,AuthorizationSet * auth_list)1131 static bool get_enum(const ASN1_INTEGER* asn1_int, TypedEnumTag<Type, Tag, KeymasterEnum> tag,
1132 AuthorizationSet* auth_list) {
1133 if (!asn1_int) return true;
1134 return auth_list->push_back(tag, static_cast<KeymasterEnum>(ASN1_INTEGER_get(asn1_int)));
1135 }
1136
1137 // Add the specified ulong tag/value pair to auth_list.
get_ulong(const ASN1_INTEGER * asn1_int,keymaster_tag_t tag,AuthorizationSet * auth_list)1138 static bool get_ulong(const ASN1_INTEGER* asn1_int, keymaster_tag_t tag,
1139 AuthorizationSet* auth_list) {
1140 if (!asn1_int) return true;
1141 UniquePtr<BIGNUM, BIGNUM_Delete> bn(ASN1_INTEGER_to_BN(asn1_int, nullptr));
1142 if (!bn.get()) return false;
1143 uint64_t ulong = 0;
1144 BN_get_u64(bn.get(), &ulong);
1145 return auth_list->push_back(keymaster_param_long(tag, ulong));
1146 }
1147
1148 // Extract the values from the specified ASN.1 record and place them in auth_list.
extract_auth_list(const KM_AUTH_LIST * record,AuthorizationSet * auth_list)1149 keymaster_error_t extract_auth_list(const KM_AUTH_LIST* record, AuthorizationSet* auth_list) {
1150 if (!record) return KM_ERROR_OK;
1151
1152 // Purpose
1153 if (!get_repeated_enums(record->purpose, TAG_PURPOSE, auth_list)) {
1154 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1155 }
1156
1157 // Algorithm
1158 if (!get_enum(record->algorithm, TAG_ALGORITHM, auth_list)) {
1159 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1160 }
1161
1162 // Key size
1163 if (record->key_size &&
1164 !auth_list->push_back(TAG_KEY_SIZE, ASN1_INTEGER_get(record->key_size))) {
1165 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1166 }
1167
1168 // Block mode
1169 if (!get_repeated_enums(record->block_mode, TAG_BLOCK_MODE, auth_list)) {
1170 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1171 }
1172
1173 // Digest
1174 if (!get_repeated_enums(record->digest, TAG_DIGEST, auth_list)) {
1175 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1176 }
1177
1178 // Padding
1179 if (!get_repeated_enums(record->padding, TAG_PADDING, auth_list)) {
1180 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1181 }
1182
1183 // Caller nonce
1184 if (record->caller_nonce && !auth_list->push_back(TAG_CALLER_NONCE)) {
1185 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1186 }
1187
1188 // Min mac length
1189 if (!get_ulong(record->min_mac_length, TAG_MIN_MAC_LENGTH, auth_list)) {
1190 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1191 }
1192
1193 // EC curve
1194 if (!get_enum(record->ec_curve, TAG_EC_CURVE, auth_list)) {
1195 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1196 }
1197
1198 // RSA public exponent
1199 if (!get_ulong(record->rsa_public_exponent, TAG_RSA_PUBLIC_EXPONENT, auth_list)) {
1200 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1201 }
1202
1203 // Rsa Oaep Mgf Digest
1204 if (!get_repeated_enums(record->mgf_digest, TAG_RSA_OAEP_MGF_DIGEST, auth_list)) {
1205 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1206 }
1207
1208 // Rollback resistance
1209 if (record->rollback_resistance && !auth_list->push_back(TAG_ROLLBACK_RESISTANCE)) {
1210 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1211 }
1212
1213 // Early boot only
1214 if (record->early_boot_only && !auth_list->push_back(TAG_EARLY_BOOT_ONLY)) {
1215 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1216 }
1217
1218 // Active date time
1219 if (!get_ulong(record->active_date_time, TAG_ACTIVE_DATETIME, auth_list)) {
1220 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1221 }
1222
1223 // Origination expire date time
1224 if (!get_ulong(record->origination_expire_date_time, TAG_ORIGINATION_EXPIRE_DATETIME,
1225 auth_list)) {
1226 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1227 }
1228
1229 // Usage Expire date time
1230 if (!get_ulong(record->usage_expire_date_time, TAG_USAGE_EXPIRE_DATETIME, auth_list)) {
1231 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1232 }
1233
1234 // Usage count limit
1235 if (record->usage_count_limit &&
1236 !auth_list->push_back(TAG_USAGE_COUNT_LIMIT, ASN1_INTEGER_get(record->usage_count_limit))) {
1237 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1238 }
1239
1240 // No auth required
1241 if (record->no_auth_required && !auth_list->push_back(TAG_NO_AUTH_REQUIRED)) {
1242 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1243 }
1244
1245 // User auth type
1246 if (!get_enum(record->user_auth_type, TAG_USER_AUTH_TYPE, auth_list)) {
1247 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1248 }
1249
1250 // Auth timeout
1251 if (record->auth_timeout &&
1252 !auth_list->push_back(TAG_AUTH_TIMEOUT, ASN1_INTEGER_get(record->auth_timeout))) {
1253 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1254 }
1255
1256 // Allow while on body
1257 if (record->allow_while_on_body && !auth_list->push_back(TAG_ALLOW_WHILE_ON_BODY)) {
1258 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1259 }
1260
1261 // trusted user presence required
1262 if (record->trusted_user_presence_required &&
1263 !auth_list->push_back(TAG_TRUSTED_USER_PRESENCE_REQUIRED)) {
1264 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1265 }
1266
1267 // trusted confirmation required
1268 if (record->trusted_confirmation_required &&
1269 !auth_list->push_back(TAG_TRUSTED_CONFIRMATION_REQUIRED)) {
1270 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1271 }
1272
1273 // Unlocked device required
1274 if (record->unlocked_device_required && !auth_list->push_back(TAG_UNLOCKED_DEVICE_REQUIRED)) {
1275 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1276 }
1277
1278 // All applications
1279 if (record->all_applications && !auth_list->push_back(TAG_ALL_APPLICATIONS)) {
1280 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1281 }
1282
1283 // Application ID
1284 if (record->application_id &&
1285 !auth_list->push_back(TAG_APPLICATION_ID, record->application_id->data,
1286 record->application_id->length)) {
1287 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1288 }
1289
1290 // Creation date time
1291 if (!get_ulong(record->creation_date_time, TAG_CREATION_DATETIME, auth_list)) {
1292 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1293 }
1294
1295 // Origin
1296 if (!get_enum(record->origin, TAG_ORIGIN, auth_list)) {
1297 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1298 }
1299
1300 // Rollback resistant
1301 if (record->rollback_resistant && !auth_list->push_back(TAG_ROLLBACK_RESISTANT)) {
1302 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1303 }
1304
1305 // Root of trust
1306 if (record->root_of_trust) {
1307 KM_ROOT_OF_TRUST* rot = record->root_of_trust;
1308 if (!rot->verified_boot_key) return KM_ERROR_INVALID_KEY_BLOB;
1309
1310 // Other root of trust fields are not mapped to auth set entries.
1311 }
1312
1313 // OS Version
1314 if (record->os_version &&
1315 !auth_list->push_back(TAG_OS_VERSION, ASN1_INTEGER_get(record->os_version))) {
1316 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1317 }
1318
1319 // OS Patch level
1320 if (record->os_patchlevel &&
1321 !auth_list->push_back(TAG_OS_PATCHLEVEL, ASN1_INTEGER_get(record->os_patchlevel))) {
1322 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1323 }
1324
1325 // attestation application Id
1326 if (record->attestation_application_id &&
1327 !auth_list->push_back(TAG_ATTESTATION_APPLICATION_ID,
1328 record->attestation_application_id->data,
1329 record->attestation_application_id->length)) {
1330 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1331 }
1332
1333 // Brand name
1334 if (record->attestation_id_brand &&
1335 !auth_list->push_back(TAG_ATTESTATION_ID_BRAND, record->attestation_id_brand->data,
1336 record->attestation_id_brand->length)) {
1337 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1338 }
1339
1340 // Device name
1341 if (record->attestation_id_device &&
1342 !auth_list->push_back(TAG_ATTESTATION_ID_DEVICE, record->attestation_id_device->data,
1343 record->attestation_id_device->length)) {
1344 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1345 }
1346
1347 // Product name
1348 if (record->attestation_id_product &&
1349 !auth_list->push_back(TAG_ATTESTATION_ID_PRODUCT, record->attestation_id_product->data,
1350 record->attestation_id_product->length)) {
1351 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1352 }
1353
1354 // Serial number
1355 if (record->attestation_id_serial &&
1356 !auth_list->push_back(TAG_ATTESTATION_ID_SERIAL, record->attestation_id_serial->data,
1357 record->attestation_id_serial->length)) {
1358 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1359 }
1360
1361 // IMEI
1362 if (record->attestation_id_imei &&
1363 !auth_list->push_back(TAG_ATTESTATION_ID_IMEI, record->attestation_id_imei->data,
1364 record->attestation_id_imei->length)) {
1365 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1366 }
1367
1368 // MEID
1369 if (record->attestation_id_meid &&
1370 !auth_list->push_back(TAG_ATTESTATION_ID_MEID, record->attestation_id_meid->data,
1371 record->attestation_id_meid->length)) {
1372 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1373 }
1374
1375 // Manufacturer name
1376 if (record->attestation_id_manufacturer &&
1377 !auth_list->push_back(TAG_ATTESTATION_ID_MANUFACTURER,
1378 record->attestation_id_manufacturer->data,
1379 record->attestation_id_manufacturer->length)) {
1380 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1381 }
1382
1383 // Model name
1384 if (record->attestation_id_model &&
1385 !auth_list->push_back(TAG_ATTESTATION_ID_MODEL, record->attestation_id_model->data,
1386 record->attestation_id_model->length)) {
1387 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1388 }
1389
1390 // vendor patch level
1391 if (record->vendor_patchlevel &&
1392 !auth_list->push_back(TAG_VENDOR_PATCHLEVEL, ASN1_INTEGER_get(record->vendor_patchlevel))) {
1393 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1394 }
1395
1396 // boot patch level
1397 if (record->boot_patch_level &&
1398 !auth_list->push_back(TAG_BOOT_PATCHLEVEL, ASN1_INTEGER_get(record->boot_patch_level))) {
1399 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1400 }
1401
1402 // device unique attestation
1403 if (record->device_unique_attestation && !auth_list->push_back(TAG_DEVICE_UNIQUE_ATTESTATION)) {
1404 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1405 }
1406
1407 // identity credential key
1408 if (record->identity_credential_key && !auth_list->push_back(TAG_IDENTITY_CREDENTIAL_KEY)) {
1409 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1410 }
1411
1412 // Second IMEI
1413 if (record->attestation_id_second_imei &&
1414 !auth_list->push_back(TAG_ATTESTATION_ID_SECOND_IMEI,
1415 record->attestation_id_second_imei->data,
1416 record->attestation_id_second_imei->length)) {
1417 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1418 }
1419
1420 // Module hash
1421 if (record->module_hash && !auth_list->push_back(TAG_MODULE_HASH, record->module_hash->data,
1422 record->module_hash->length)) {
1423 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1424 }
1425
1426 return KM_ERROR_OK;
1427 }
1428
1429 // Parse the DER-encoded attestation record, placing the results in keymaster_version,
1430 // attestation_challenge, software_enforced, tee_enforced and unique_id.
parse_attestation_record(const uint8_t * asn1_key_desc,size_t asn1_key_desc_len,uint32_t * attestation_version,keymaster_security_level_t * attestation_security_level,uint32_t * keymaster_version,keymaster_security_level_t * keymaster_security_level,keymaster_blob_t * attestation_challenge,AuthorizationSet * software_enforced,AuthorizationSet * tee_enforced,keymaster_blob_t * unique_id)1431 keymaster_error_t parse_attestation_record(const uint8_t* asn1_key_desc, size_t asn1_key_desc_len,
1432 uint32_t* attestation_version, //
1433 keymaster_security_level_t* attestation_security_level,
1434 uint32_t* keymaster_version,
1435 keymaster_security_level_t* keymaster_security_level,
1436 keymaster_blob_t* attestation_challenge,
1437 AuthorizationSet* software_enforced,
1438 AuthorizationSet* tee_enforced,
1439 keymaster_blob_t* unique_id) {
1440 const uint8_t* p = asn1_key_desc;
1441 UniquePtr<KM_KEY_DESCRIPTION, KM_KEY_DESCRIPTION_Delete> record(
1442 d2i_KM_KEY_DESCRIPTION(nullptr, &p, asn1_key_desc_len));
1443 if (!record.get()) return TranslateLastOpenSslError();
1444
1445 *attestation_version = ASN1_INTEGER_get(record->attestation_version);
1446 *attestation_security_level = static_cast<keymaster_security_level_t>(
1447 ASN1_ENUMERATED_get(record->attestation_security_level));
1448 *keymaster_version = ASN1_INTEGER_get(record->keymaster_version);
1449 *keymaster_security_level = static_cast<keymaster_security_level_t>(
1450 ASN1_ENUMERATED_get(record->keymaster_security_level));
1451
1452 attestation_challenge->data =
1453 dup_buffer(record->attestation_challenge->data, record->attestation_challenge->length);
1454 attestation_challenge->data_length = record->attestation_challenge->length;
1455
1456 unique_id->data = dup_buffer(record->unique_id->data, record->unique_id->length);
1457 unique_id->data_length = record->unique_id->length;
1458
1459 keymaster_error_t error = extract_auth_list(record->software_enforced, software_enforced);
1460 if (error != KM_ERROR_OK) return error;
1461
1462 return extract_auth_list(record->tee_enforced, tee_enforced);
1463 }
1464
parse_root_of_trust(const uint8_t * asn1_key_desc,size_t asn1_key_desc_len,keymaster_blob_t * verified_boot_key,keymaster_verified_boot_t * verified_boot_state,bool * device_locked)1465 keymaster_error_t parse_root_of_trust(const uint8_t* asn1_key_desc, size_t asn1_key_desc_len,
1466 keymaster_blob_t* verified_boot_key,
1467 keymaster_verified_boot_t* verified_boot_state,
1468 bool* device_locked) {
1469 const uint8_t* p = asn1_key_desc;
1470 UniquePtr<KM_KEY_DESCRIPTION, KM_KEY_DESCRIPTION_Delete> record(
1471 d2i_KM_KEY_DESCRIPTION(nullptr, &p, asn1_key_desc_len));
1472 if (!record.get()) {
1473 return TranslateLastOpenSslError();
1474 }
1475 if (!record->tee_enforced) {
1476 return KM_ERROR_INVALID_ARGUMENT;
1477 }
1478 if (!record->tee_enforced->root_of_trust) {
1479 return KM_ERROR_INVALID_ARGUMENT;
1480 }
1481 if (!record->tee_enforced->root_of_trust->verified_boot_key) {
1482 return KM_ERROR_INVALID_ARGUMENT;
1483 }
1484 KM_ROOT_OF_TRUST* root_of_trust = record->tee_enforced->root_of_trust;
1485 verified_boot_key->data = dup_buffer(root_of_trust->verified_boot_key->data,
1486 root_of_trust->verified_boot_key->length);
1487 verified_boot_key->data_length = root_of_trust->verified_boot_key->length;
1488 *verified_boot_state = static_cast<keymaster_verified_boot_t>(
1489 ASN1_ENUMERATED_get(root_of_trust->verified_boot_state));
1490 *device_locked = root_of_trust->device_locked;
1491 return KM_ERROR_OK;
1492 }
1493
1494 // Parse the EAT-encoded attestation record, placing the results in keymaster_version,
1495 // attestation_challenge, software_enforced, tee_enforced and unique_id.
parse_eat_record(const uint8_t * eat_key_desc,size_t eat_key_desc_len,uint32_t * attestation_version,keymaster_security_level_t * attestation_security_level,uint32_t * keymaster_version,keymaster_security_level_t * keymaster_security_level,keymaster_blob_t * attestation_challenge,AuthorizationSet * software_enforced,AuthorizationSet * tee_enforced,keymaster_blob_t * unique_id,keymaster_blob_t * verified_boot_key,keymaster_verified_boot_t * verified_boot_state,bool * device_locked,std::vector<int64_t> * unexpected_claims)1496 keymaster_error_t parse_eat_record(
1497 const uint8_t* eat_key_desc, size_t eat_key_desc_len, uint32_t* attestation_version,
1498 keymaster_security_level_t* attestation_security_level, uint32_t* keymaster_version,
1499 keymaster_security_level_t* keymaster_security_level, keymaster_blob_t* attestation_challenge,
1500 AuthorizationSet* software_enforced, AuthorizationSet* tee_enforced,
1501 keymaster_blob_t* unique_id, keymaster_blob_t* verified_boot_key,
1502 keymaster_verified_boot_t* verified_boot_state, bool* device_locked,
1503 std::vector<int64_t>* unexpected_claims) {
1504 auto [top_level_item, next_pos, error] = cppbor::parse(eat_key_desc, eat_key_desc_len);
1505 ASSERT_OR_RETURN_ERROR(top_level_item, KM_ERROR_INVALID_TAG);
1506 const cppbor::Map* eat_map = top_level_item->asMap();
1507 ASSERT_OR_RETURN_ERROR(eat_map, KM_ERROR_INVALID_TAG);
1508 bool verified_or_self_signed = false;
1509
1510 for (size_t i = 0; i < eat_map->size(); i++) {
1511 auto& [key_item, value_item] = (*eat_map)[i];
1512 const cppbor::Int* key = key_item->asInt();
1513 ASSERT_OR_RETURN_ERROR(key, (KM_ERROR_INVALID_TAG));
1514
1515 // The following values will either hold the typed value, or be null (if not the right
1516 // type).
1517 const cppbor::Int* int_value = value_item->asInt();
1518 const cppbor::Bstr* bstr_value = value_item->asBstr();
1519 const cppbor::Simple* simple_value = value_item->asSimple();
1520 const cppbor::Array* array_value = value_item->asArray();
1521 const cppbor::Map* map_value = value_item->asMap();
1522
1523 keymaster_error_t error;
1524 switch ((EatClaim)key->value()) {
1525 default:
1526 unexpected_claims->push_back(key->value());
1527 break;
1528 case EatClaim::ATTESTATION_VERSION:
1529 ASSERT_OR_RETURN_ERROR(int_value, KM_ERROR_INVALID_TAG);
1530 *attestation_version = int_value->value();
1531 break;
1532 case EatClaim::SECURITY_LEVEL:
1533 ASSERT_OR_RETURN_ERROR(int_value, KM_ERROR_INVALID_TAG);
1534 switch ((EatSecurityLevel)int_value->value()) {
1535 // TODO: Is my assumption correct that the security level of the attestation data should
1536 // always be equal to the security level of keymint, as the attestation data always
1537 // lives in the top-level module?
1538 case EatSecurityLevel::UNRESTRICTED:
1539 *keymaster_security_level = *attestation_security_level =
1540 KM_SECURITY_LEVEL_SOFTWARE;
1541 break;
1542 case EatSecurityLevel::SECURE_RESTRICTED:
1543 *keymaster_security_level = *attestation_security_level =
1544 KM_SECURITY_LEVEL_TRUSTED_ENVIRONMENT;
1545 break;
1546 case EatSecurityLevel::HARDWARE:
1547 *keymaster_security_level = *attestation_security_level =
1548 KM_SECURITY_LEVEL_STRONGBOX;
1549 break;
1550 default:
1551 return KM_ERROR_INVALID_TAG;
1552 }
1553 break;
1554 case EatClaim::KEYMASTER_VERSION:
1555 ASSERT_OR_RETURN_ERROR(int_value, KM_ERROR_INVALID_TAG);
1556 *keymaster_version = int_value->value();
1557 break;
1558 case EatClaim::SUBMODS:
1559 ASSERT_OR_RETURN_ERROR(map_value, KM_ERROR_INVALID_TAG);
1560 for (size_t j = 0; j < map_value->size(); j++) {
1561 auto& [submod_key, submod_value] = (*map_value)[j];
1562 const cppbor::Map* submod_map = submod_value->asMap();
1563 ASSERT_OR_RETURN_ERROR(submod_map, KM_ERROR_INVALID_TAG);
1564 error = parse_eat_submod(submod_map, software_enforced, tee_enforced);
1565 if (error != KM_ERROR_OK) return error;
1566 }
1567 break;
1568 case EatClaim::CTI:
1569 error = bstr_to_blob(bstr_value, unique_id);
1570 if (error != KM_ERROR_OK) return error;
1571 break;
1572 case EatClaim::NONCE:
1573 error = bstr_to_blob(bstr_value, attestation_challenge);
1574 if (error != KM_ERROR_OK) return error;
1575 break;
1576 case EatClaim::VERIFIED_BOOT_KEY:
1577 error = bstr_to_blob(bstr_value, verified_boot_key);
1578 if (error != KM_ERROR_OK) return error;
1579 break;
1580 case EatClaim::VERIFIED_BOOT_HASH:
1581 // Not parsing this for now.
1582 break;
1583 case EatClaim::DEVICE_UNIQUE_ATTESTATION:
1584 if (value_item->asSimple() == nullptr || !value_item->asSimple()->asBool()->value()) {
1585 return KM_ERROR_INVALID_TAG;
1586 }
1587 // Not parsing this for now.
1588 break;
1589 case EatClaim::DEVICE_LOCKED:
1590 ASSERT_OR_RETURN_ERROR(simple_value->asBool(), KM_ERROR_INVALID_TAG);
1591 *device_locked = simple_value->asBool()->value();
1592 break;
1593 case EatClaim::BOOT_STATE:
1594 ASSERT_OR_RETURN_ERROR(array_value, KM_ERROR_INVALID_TAG);
1595 ASSERT_OR_RETURN_ERROR(array_value->size() == 5, KM_ERROR_INVALID_TAG);
1596 ASSERT_OR_RETURN_ERROR((*array_value)[4]->asSimple()->asBool()->value() == false,
1597 KM_ERROR_INVALID_TAG);
1598 verified_or_self_signed = (*array_value)[0]->asSimple()->asBool()->value();
1599 ASSERT_OR_RETURN_ERROR(verified_or_self_signed ==
1600 (*array_value)[1]->asSimple()->asBool()->value(),
1601 KM_ERROR_INVALID_TAG);
1602 ASSERT_OR_RETURN_ERROR(verified_or_self_signed ==
1603 (*array_value)[2]->asSimple()->asBool()->value(),
1604 KM_ERROR_INVALID_TAG);
1605 ASSERT_OR_RETURN_ERROR(verified_or_self_signed ==
1606 (*array_value)[3]->asSimple()->asBool()->value(),
1607 KM_ERROR_INVALID_TAG);
1608 break;
1609 case EatClaim::OFFICIAL_BUILD:
1610 *verified_boot_state = KM_VERIFIED_BOOT_VERIFIED;
1611 break;
1612 }
1613 }
1614
1615 if (*verified_boot_state == KM_VERIFIED_BOOT_VERIFIED) {
1616 (void)(verified_boot_state);
1617 // TODO: re-enable this
1618 // ASSERT_OR_RETURN_ERROR(verified_or_self_signed, KM_ERROR_INVALID_TAG);
1619 } else {
1620 *verified_boot_state =
1621 verified_or_self_signed ? KM_VERIFIED_BOOT_SELF_SIGNED : KM_VERIFIED_BOOT_UNVERIFIED;
1622 }
1623
1624 return KM_ERROR_OK;
1625 }
1626
parse_submod_values(AuthorizationSetBuilder * set_builder,int * auth_set_security_level,const cppbor::Map * submod_map)1627 keymaster_error_t parse_submod_values(AuthorizationSetBuilder* set_builder,
1628 int* auth_set_security_level, const cppbor::Map* submod_map) {
1629 ASSERT_OR_RETURN_ERROR(set_builder, KM_ERROR_UNEXPECTED_NULL_POINTER);
1630 for (size_t i = 0; i < submod_map->size(); i++) {
1631 auto& [key_item, value_item] = (*submod_map)[i];
1632 const cppbor::Int* key_int = key_item->asInt();
1633 ASSERT_OR_RETURN_ERROR(key_int, KM_ERROR_INVALID_TAG);
1634 int key = key_int->value();
1635 keymaster_error_t error;
1636 keymaster_blob_t blob;
1637
1638 switch ((EatClaim)key) {
1639 default:
1640 return KM_ERROR_INVALID_TAG;
1641 case EatClaim::ALGORITHM:
1642 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1643 set_builder->Authorization(
1644 TAG_ALGORITHM, static_cast<keymaster_algorithm_t>(value_item->asInt()->value()));
1645 break;
1646 case EatClaim::EC_CURVE:
1647 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1648 set_builder->Authorization(
1649 TAG_EC_CURVE, static_cast<keymaster_ec_curve_t>(value_item->asInt()->value()));
1650 break;
1651 case EatClaim::USER_AUTH_TYPE:
1652 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1653 set_builder->Authorization(TAG_USER_AUTH_TYPE, static_cast<hw_authenticator_type_t>(
1654 value_item->asInt()->value()));
1655 break;
1656 case EatClaim::ORIGIN:
1657 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1658 set_builder->Authorization(
1659 TAG_ORIGIN, static_cast<keymaster_key_origin_t>(value_item->asInt()->value()));
1660 break;
1661 case EatClaim::PURPOSE:
1662 for (size_t j = 0; j < value_item->asArray()->size(); j++) {
1663 set_builder->Authorization(TAG_PURPOSE,
1664 static_cast<keymaster_purpose_t>(
1665 (*value_item->asArray())[j]->asInt()->value()));
1666 }
1667 break;
1668 case EatClaim::PADDING:
1669 for (size_t j = 0; j < value_item->asArray()->size(); j++) {
1670 set_builder->Authorization(TAG_PADDING,
1671 static_cast<keymaster_padding_t>(
1672 (*value_item->asArray())[j]->asInt()->value()));
1673 }
1674 break;
1675 case EatClaim::DIGEST:
1676 for (size_t j = 0; j < value_item->asArray()->size(); j++) {
1677 set_builder->Authorization(
1678 TAG_DIGEST,
1679 static_cast<keymaster_digest_t>((*value_item->asArray())[j]->asInt()->value()));
1680 }
1681 break;
1682 case EatClaim::BLOCK_MODE:
1683 for (size_t j = 0; j < value_item->asArray()->size(); j++) {
1684 set_builder->Authorization(TAG_BLOCK_MODE,
1685 static_cast<keymaster_block_mode_t>(
1686 (*value_item->asArray())[j]->asInt()->value()));
1687 }
1688 break;
1689 case EatClaim::KEY_SIZE:
1690 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1691 set_builder->Authorization(TAG_KEY_SIZE, value_item->asInt()->value());
1692 break;
1693 case EatClaim::AUTH_TIMEOUT:
1694 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1695 set_builder->Authorization(TAG_AUTH_TIMEOUT, value_item->asInt()->value());
1696 break;
1697 case EatClaim::OS_VERSION:
1698 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1699 set_builder->Authorization(TAG_OS_VERSION, value_item->asInt()->value());
1700 break;
1701 case EatClaim::OS_PATCHLEVEL:
1702 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1703 set_builder->Authorization(TAG_OS_PATCHLEVEL, value_item->asInt()->value());
1704 break;
1705 case EatClaim::MIN_MAC_LENGTH:
1706 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1707 set_builder->Authorization(TAG_MIN_MAC_LENGTH, value_item->asInt()->value());
1708 break;
1709 case EatClaim::BOOT_PATCHLEVEL:
1710 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1711 set_builder->Authorization(TAG_BOOT_PATCHLEVEL, value_item->asInt()->value());
1712 break;
1713 case EatClaim::VENDOR_PATCHLEVEL:
1714 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1715 set_builder->Authorization(TAG_VENDOR_PATCHLEVEL, value_item->asInt()->value());
1716 break;
1717 case EatClaim::RSA_PUBLIC_EXPONENT:
1718 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1719 set_builder->Authorization(TAG_RSA_PUBLIC_EXPONENT, value_item->asInt()->value());
1720 break;
1721 case EatClaim::ACTIVE_DATETIME:
1722 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1723 set_builder->Authorization(TAG_ACTIVE_DATETIME, value_item->asInt()->value());
1724 break;
1725 case EatClaim::ORIGINATION_EXPIRE_DATETIME:
1726 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1727 set_builder->Authorization(TAG_ORIGINATION_EXPIRE_DATETIME,
1728 value_item->asInt()->value());
1729 break;
1730 case EatClaim::USAGE_EXPIRE_DATETIME:
1731 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1732 set_builder->Authorization(TAG_USAGE_EXPIRE_DATETIME, value_item->asInt()->value());
1733 break;
1734 case EatClaim::IAT:
1735 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1736 set_builder->Authorization(TAG_CREATION_DATETIME, value_item->asInt()->value());
1737 break;
1738 case EatClaim::NO_AUTH_REQUIRED:
1739 if (value_item->asSimple() == nullptr || !value_item->asSimple()->asBool()->value()) {
1740 return KM_ERROR_INVALID_TAG;
1741 }
1742 set_builder->Authorization(TAG_NO_AUTH_REQUIRED);
1743 break;
1744 case EatClaim::ALL_APPLICATIONS:
1745 if (value_item->asSimple() == nullptr || !value_item->asSimple()->asBool()->value()) {
1746 return KM_ERROR_INVALID_TAG;
1747 }
1748 set_builder->Authorization(TAG_ALL_APPLICATIONS);
1749 break;
1750 case EatClaim::ROLLBACK_RESISTANT:
1751 if (value_item->asSimple() == nullptr || !value_item->asSimple()->asBool()->value()) {
1752 return KM_ERROR_INVALID_TAG;
1753 }
1754 set_builder->Authorization(TAG_ROLLBACK_RESISTANT);
1755 break;
1756 case EatClaim::ALLOW_WHILE_ON_BODY:
1757 if (value_item->asSimple() == nullptr || !value_item->asSimple()->asBool()->value()) {
1758 return KM_ERROR_INVALID_TAG;
1759 }
1760 set_builder->Authorization(TAG_ALLOW_WHILE_ON_BODY);
1761 break;
1762 case EatClaim::UNLOCKED_DEVICE_REQUIRED:
1763 if (value_item->asSimple() == nullptr || !value_item->asSimple()->asBool()->value()) {
1764 return KM_ERROR_INVALID_TAG;
1765 }
1766 set_builder->Authorization(TAG_UNLOCKED_DEVICE_REQUIRED);
1767 break;
1768 case EatClaim::CALLER_NONCE:
1769 if (value_item->asSimple() == nullptr || !value_item->asSimple()->asBool()->value()) {
1770 return KM_ERROR_INVALID_TAG;
1771 }
1772 set_builder->Authorization(TAG_CALLER_NONCE);
1773 break;
1774 case EatClaim::TRUSTED_CONFIRMATION_REQUIRED:
1775 if (value_item->asSimple() == nullptr || !value_item->asSimple()->asBool()->value()) {
1776 return KM_ERROR_INVALID_TAG;
1777 }
1778 set_builder->Authorization(TAG_TRUSTED_CONFIRMATION_REQUIRED);
1779 break;
1780 case EatClaim::EARLY_BOOT_ONLY:
1781 if (value_item->asSimple() == nullptr || !value_item->asSimple()->asBool()->value()) {
1782 return KM_ERROR_INVALID_TAG;
1783 }
1784 set_builder->Authorization(TAG_EARLY_BOOT_ONLY);
1785 break;
1786 case EatClaim::IDENTITY_CREDENTIAL_KEY:
1787 if (value_item->asSimple() == nullptr || !value_item->asSimple()->asBool()->value()) {
1788 return KM_ERROR_INVALID_TAG;
1789 }
1790 set_builder->Authorization(TAG_IDENTITY_CREDENTIAL_KEY);
1791 break;
1792 case EatClaim::STORAGE_KEY:
1793 if (value_item->asSimple() == nullptr || !value_item->asSimple()->asBool()->value()) {
1794 return KM_ERROR_INVALID_TAG;
1795 }
1796 set_builder->Authorization(TAG_STORAGE_KEY);
1797 break;
1798 case EatClaim::TRUSTED_USER_PRESENCE_REQUIRED:
1799 if (value_item->asSimple() == nullptr || !value_item->asSimple()->asBool()->value()) {
1800 return KM_ERROR_INVALID_TAG;
1801 }
1802 set_builder->Authorization(TAG_TRUSTED_USER_PRESENCE_REQUIRED);
1803 break;
1804 case EatClaim::DEVICE_UNIQUE_ATTESTATION:
1805 if (value_item->asSimple() == nullptr || !value_item->asSimple()->asBool()->value()) {
1806 return KM_ERROR_INVALID_TAG;
1807 }
1808 set_builder->Authorization(TAG_DEVICE_UNIQUE_ATTESTATION);
1809 break;
1810 case EatClaim::APPLICATION_ID:
1811 error = bstr_to_blob(value_item->asBstr(), &blob);
1812 if (error != KM_ERROR_OK) return error;
1813 set_builder->Authorization(TAG_APPLICATION_ID, blob);
1814 break;
1815 case EatClaim::ATTESTATION_APPLICATION_ID:
1816 error = bstr_to_blob(value_item->asBstr(), &blob);
1817 if (error != KM_ERROR_OK) return error;
1818 set_builder->Authorization(TAG_ATTESTATION_APPLICATION_ID, blob);
1819 break;
1820 case EatClaim::ATTESTATION_ID_BRAND:
1821 error = bstr_to_blob(value_item->asBstr(), &blob);
1822 if (error != KM_ERROR_OK) return error;
1823 set_builder->Authorization(TAG_ATTESTATION_ID_BRAND, blob);
1824 break;
1825 case EatClaim::ATTESTATION_ID_DEVICE:
1826 error = bstr_to_blob(value_item->asBstr(), &blob);
1827 if (error != KM_ERROR_OK) return error;
1828 set_builder->Authorization(TAG_ATTESTATION_ID_DEVICE, blob);
1829 break;
1830 case EatClaim::ATTESTATION_ID_PRODUCT:
1831 error = bstr_to_blob(value_item->asBstr(), &blob);
1832 if (error != KM_ERROR_OK) return error;
1833 set_builder->Authorization(TAG_ATTESTATION_ID_PRODUCT, blob);
1834 break;
1835 case EatClaim::ATTESTATION_ID_SERIAL:
1836 error = bstr_to_blob(value_item->asBstr(), &blob);
1837 if (error != KM_ERROR_OK) return error;
1838 set_builder->Authorization(TAG_ATTESTATION_ID_SERIAL, blob);
1839 break;
1840 case EatClaim::UEID:
1841 error = ueid_to_imei_blob(value_item->asBstr(), &blob);
1842 if (error != KM_ERROR_OK) return error;
1843 set_builder->Authorization(TAG_ATTESTATION_ID_IMEI, blob);
1844 break;
1845 case EatClaim::ATTESTATION_ID_MEID:
1846 error = bstr_to_blob(value_item->asBstr(), &blob);
1847 if (error != KM_ERROR_OK) return error;
1848 set_builder->Authorization(TAG_ATTESTATION_ID_MEID, blob);
1849 break;
1850 case EatClaim::ATTESTATION_ID_MANUFACTURER:
1851 error = bstr_to_blob(value_item->asBstr(), &blob);
1852 if (error != KM_ERROR_OK) return error;
1853 set_builder->Authorization(TAG_ATTESTATION_ID_MANUFACTURER, blob);
1854 break;
1855 case EatClaim::ATTESTATION_ID_MODEL:
1856 error = bstr_to_blob(value_item->asBstr(), &blob);
1857 if (error != KM_ERROR_OK) return error;
1858 set_builder->Authorization(TAG_ATTESTATION_ID_MODEL, blob);
1859 break;
1860 case EatClaim::CONFIRMATION_TOKEN:
1861 error = bstr_to_blob(value_item->asBstr(), &blob);
1862 if (error != KM_ERROR_OK) return error;
1863 set_builder->Authorization(TAG_CONFIRMATION_TOKEN, blob);
1864 break;
1865 case EatClaim::SECURITY_LEVEL:
1866 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1867 *auth_set_security_level = value_item->asInt()->value();
1868 }
1869 }
1870
1871 return KM_ERROR_OK;
1872 }
1873
parse_eat_submod(const cppbor::Map * submod_values,AuthorizationSet * software_enforced,AuthorizationSet * tee_enforced)1874 keymaster_error_t parse_eat_submod(const cppbor::Map* submod_values,
1875 AuthorizationSet* software_enforced,
1876 AuthorizationSet* tee_enforced) {
1877 AuthorizationSetBuilder auth_set_builder;
1878 int auth_set_security_level = 0;
1879 keymaster_error_t error =
1880 parse_submod_values(&auth_set_builder, &auth_set_security_level, submod_values);
1881 if (error) return error;
1882 switch ((EatSecurityLevel)auth_set_security_level) {
1883 case EatSecurityLevel::HARDWARE:
1884 // Hardware attestation should never occur in a submod of another EAT.
1885 [[fallthrough]];
1886 default:
1887 return KM_ERROR_INVALID_TAG;
1888 case EatSecurityLevel::UNRESTRICTED:
1889 *software_enforced = AuthorizationSet(auth_set_builder);
1890 break;
1891 case EatSecurityLevel::SECURE_RESTRICTED:
1892 *tee_enforced = AuthorizationSet(auth_set_builder);
1893 break;
1894 }
1895
1896 return KM_ERROR_OK;
1897 }
1898 } // namespace keymaster
1899