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 }
696
697 keymaster_tag_type_t type = keymaster_tag_get_type(entry.tag);
698 switch (type) {
699 case KM_ENUM:
700 case KM_ENUM_REP:
701 case KM_UINT:
702 case KM_UINT_REP: {
703 ASSERT_OR_RETURN_ERROR((keymaster_tag_repeatable(entry.tag) && integer_set) ||
704 (!keymaster_tag_repeatable(entry.tag) && integer_ptr),
705 KM_ERROR_INVALID_TAG);
706
707 UniquePtr<ASN1_INTEGER, ASN1_INTEGER_Delete> value(ASN1_INTEGER_new());
708 if (!value.get()) {
709 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
710 }
711 if (!ASN1_INTEGER_set(value.get(), get_uint32_value(entry))) {
712 return TranslateLastOpenSslError();
713 }
714
715 insert_integer(value.release(), integer_ptr, integer_set);
716 break;
717 }
718
719 case KM_ULONG:
720 case KM_ULONG_REP:
721 case KM_DATE: {
722 ASSERT_OR_RETURN_ERROR((keymaster_tag_repeatable(entry.tag) && integer_set) ||
723 (!keymaster_tag_repeatable(entry.tag) && integer_ptr),
724 KM_ERROR_INVALID_TAG);
725
726 UniquePtr<BIGNUM, BIGNUM_Delete> bn_value(BN_new());
727 if (!bn_value.get()) {
728 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
729 }
730
731 if (type == KM_DATE) {
732 if (!BN_set_u64(bn_value.get(), entry.date_time)) {
733 return TranslateLastOpenSslError();
734 }
735 } else {
736 if (!BN_set_u64(bn_value.get(), entry.long_integer)) {
737 return TranslateLastOpenSslError();
738 }
739 }
740
741 UniquePtr<ASN1_INTEGER, ASN1_INTEGER_Delete> value(
742 BN_to_ASN1_INTEGER(bn_value.get(), nullptr));
743 if (!value.get()) {
744 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
745 }
746
747 insert_integer(value.release(), integer_ptr, integer_set);
748 break;
749 }
750
751 case KM_BOOL:
752 ASSERT_OR_RETURN_ERROR(bool_ptr, KM_ERROR_INVALID_TAG);
753 if (!*bool_ptr) *bool_ptr = ASN1_NULL_new();
754 if (!*bool_ptr) return KM_ERROR_MEMORY_ALLOCATION_FAILED;
755 break;
756
757 /* Byte arrays*/
758 case KM_BYTES:
759 ASSERT_OR_RETURN_ERROR(string_ptr, KM_ERROR_INVALID_TAG);
760 if (!*string_ptr) {
761 *string_ptr = ASN1_OCTET_STRING_new();
762 }
763 if (!*string_ptr) {
764 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
765 }
766 if (!ASN1_OCTET_STRING_set(*string_ptr, entry.blob.data, entry.blob.data_length)) {
767 return TranslateLastOpenSslError();
768 }
769 break;
770
771 default:
772 return KM_ERROR_UNIMPLEMENTED;
773 }
774 }
775
776 keymaster_ec_curve_t ec_curve;
777 uint32_t key_size;
778 if (auth_list.Contains(TAG_ALGORITHM, KM_ALGORITHM_EC) && //
779 !auth_list.Contains(TAG_EC_CURVE) && //
780 auth_list.GetTagValue(TAG_KEY_SIZE, &key_size)) {
781 // This must be a keymaster1 key. It's an EC key with no curve. Insert the curve if we
782 // can unambiguously figure it out.
783
784 keymaster_error_t error = EcKeySizeToCurve(key_size, &ec_curve);
785 if (error != KM_ERROR_OK) return error;
786
787 UniquePtr<ASN1_INTEGER, ASN1_INTEGER_Delete> value(ASN1_INTEGER_new());
788 if (!value.get()) {
789 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
790 }
791
792 if (!ASN1_INTEGER_set(value.get(), ec_curve)) {
793 return TranslateLastOpenSslError();
794 }
795
796 insert_integer(value.release(), &record->ec_curve, nullptr);
797 }
798
799 return KM_ERROR_OK;
800 }
801
802 // Construct a CBOR-encoded attestation record containing the values from sw_enforced
803 // 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)804 keymaster_error_t build_eat_record(const AuthorizationSet& attestation_params,
805 AuthorizationSet sw_enforced, AuthorizationSet tee_enforced,
806 const AttestationContext& context,
807 std::vector<uint8_t>* eat_token) {
808 ASSERT_OR_RETURN_ERROR(eat_token, KM_ERROR_UNEXPECTED_NULL_POINTER);
809
810 cppbor::Map eat_record;
811 switch (context.GetSecurityLevel()) {
812 case KM_SECURITY_LEVEL_SOFTWARE:
813 eat_record.add(EatClaim::SECURITY_LEVEL, get_uint32_value(EatSecurityLevel::UNRESTRICTED));
814 break;
815 case KM_SECURITY_LEVEL_TRUSTED_ENVIRONMENT:
816 eat_record.add(EatClaim::SECURITY_LEVEL,
817 get_uint32_value(EatSecurityLevel::SECURE_RESTRICTED));
818 break;
819 case KM_SECURITY_LEVEL_STRONGBOX:
820 eat_record.add(EatClaim::SECURITY_LEVEL, get_uint32_value(EatSecurityLevel::HARDWARE));
821 break;
822 default:
823 return KM_ERROR_UNKNOWN_ERROR;
824 }
825
826 keymaster_error_t error;
827 const AttestationContext::VerifiedBootParams* vb_params = context.GetVerifiedBootParams(&error);
828 if (error != KM_ERROR_OK) return error;
829
830 if (vb_params->verified_boot_key.data_length) {
831 eat_record.add(EatClaim::VERIFIED_BOOT_KEY, blob_to_bstr(vb_params->verified_boot_key));
832 }
833 if (vb_params->verified_boot_hash.data_length) {
834 eat_record.add(EatClaim::VERIFIED_BOOT_HASH, blob_to_bstr(vb_params->verified_boot_hash));
835 }
836 if (vb_params->device_locked) {
837 eat_record.add(EatClaim::DEVICE_LOCKED, vb_params->device_locked);
838 }
839
840 bool verified_or_self_signed = (vb_params->verified_boot_state == KM_VERIFIED_BOOT_VERIFIED ||
841 vb_params->verified_boot_state == KM_VERIFIED_BOOT_SELF_SIGNED);
842 auto eat_boot_state = cppbor::Array()
843 .add(verified_or_self_signed) // secure-boot-enabled
844 .add(verified_or_self_signed) // debug-disabled
845 .add(verified_or_self_signed) // debug-disabled-since-boot
846 .add(verified_or_self_signed) // debug-permanent-disable
847 .add(false); // debug-full-permanent-disable (no way to verify)
848 eat_record.add(EatClaim::BOOT_STATE, std::move(eat_boot_state));
849 eat_record.add(EatClaim::OFFICIAL_BUILD,
850 vb_params->verified_boot_state == KM_VERIFIED_BOOT_VERIFIED);
851
852 eat_record.add(EatClaim::ATTESTATION_VERSION,
853 version_to_attestation_version(context.GetKmVersion()));
854 eat_record.add(EatClaim::KEYMASTER_VERSION,
855 version_to_attestation_km_version(context.GetKmVersion()));
856
857 keymaster_blob_t attestation_challenge = {nullptr, 0};
858 if (!attestation_params.GetTagValue(TAG_ATTESTATION_CHALLENGE, &attestation_challenge)) {
859 return KM_ERROR_ATTESTATION_CHALLENGE_MISSING;
860 }
861
862 if (!is_valid_attestation_challenge(attestation_challenge)) {
863 return KM_ERROR_INVALID_INPUT_LENGTH;
864 }
865
866 eat_record.add(EatClaim::NONCE, blob_to_bstr(attestation_challenge));
867
868 keymaster_blob_t attestation_app_id;
869 if (!attestation_params.GetTagValue(TAG_ATTESTATION_APPLICATION_ID, &attestation_app_id)) {
870 return KM_ERROR_ATTESTATION_APPLICATION_ID_MISSING;
871 }
872 // TODO: what should happen when sw_enforced already contains TAG_ATTESTATION_APPLICATION_ID?
873 // (as is the case in android_keymaster_test.cpp). For now, we will ignore the provided one in
874 // attestation_params if that's the case.
875 keymaster_blob_t existing_app_id;
876 if (!sw_enforced.GetTagValue(TAG_ATTESTATION_APPLICATION_ID, &existing_app_id)) {
877 sw_enforced.push_back(TAG_ATTESTATION_APPLICATION_ID, attestation_app_id);
878 }
879
880 error = context.VerifyAndCopyDeviceIds(
881 attestation_params,
882 context.GetSecurityLevel() == KM_SECURITY_LEVEL_SOFTWARE ? &sw_enforced : &tee_enforced);
883 if (error == KM_ERROR_UNIMPLEMENTED) {
884 // The KeymasterContext implementation does not support device ID attestation. Bail out if
885 // device ID attestation is being attempted.
886 for (const auto& tag : kDeviceAttestationTags) {
887 if (attestation_params.find(tag) != -1) {
888 return KM_ERROR_CANNOT_ATTEST_IDS;
889 }
890 }
891 } else if (error != KM_ERROR_OK) {
892 return error;
893 }
894
895 if (attestation_params.Contains(TAG_DEVICE_UNIQUE_ATTESTATION) &&
896 context.GetSecurityLevel() == KM_SECURITY_LEVEL_STRONGBOX) {
897 eat_record.add(EatClaim::DEVICE_UNIQUE_ATTESTATION, true);
898 }
899
900 cppbor::Map software_submod;
901 error = build_eat_submod(sw_enforced, EatSecurityLevel::UNRESTRICTED, &software_submod);
902 if (error != KM_ERROR_OK) return error;
903
904 cppbor::Map tee_submod;
905 error = build_eat_submod(tee_enforced, EatSecurityLevel::SECURE_RESTRICTED, &tee_submod);
906 if (error != KM_ERROR_OK) return error;
907
908 if (software_submod.size() + tee_submod.size() > 0) {
909 cppbor::Map submods;
910 if (software_submod.size() > 0) {
911 submods.add(kEatSubmodNameSoftware, std::move(software_submod));
912 }
913 if (tee_submod.size() > 0) {
914 submods.add(kEatSubmodNameTee, std::move(tee_submod));
915 }
916
917 eat_record.add(EatClaim::SUBMODS, std::move(submods));
918 }
919
920 if (attestation_params.GetTagValue(TAG_INCLUDE_UNIQUE_ID)) {
921 uint64_t creation_datetime;
922 // Only check sw_enforced for TAG_CREATION_DATETIME, since it shouldn't be in tee_enforced,
923 // since this implementation has no secure wall clock.
924 if (!sw_enforced.GetTagValue(TAG_CREATION_DATETIME, &creation_datetime)) {
925 LOG_E("Unique ID cannot be created without creation datetime", 0);
926 return KM_ERROR_INVALID_KEY_BLOB;
927 }
928
929 Buffer unique_id = context.GenerateUniqueId(
930 creation_datetime, attestation_app_id,
931 attestation_params.GetTagValue(TAG_RESET_SINCE_ID_ROTATION), &error);
932 if (error != KM_ERROR_OK) return error;
933
934 eat_record.add(EatClaim::CTI,
935 cppbor::Bstr(std::pair(unique_id.begin(), unique_id.available_read())));
936 }
937
938 *eat_token = eat_record.encode();
939
940 return KM_ERROR_OK;
941 }
942
build_unique_id_input(uint64_t creation_date_time,const keymaster_blob_t & application_id,bool reset_since_rotation,Buffer * input_data)943 keymaster_error_t build_unique_id_input(uint64_t creation_date_time,
944 const keymaster_blob_t& application_id,
945 bool reset_since_rotation, Buffer* input_data) {
946 if (input_data == nullptr) {
947 return KM_ERROR_UNEXPECTED_NULL_POINTER;
948 }
949 uint64_t rounded_date = creation_date_time / 2592000000LLU;
950 uint8_t* serialized_date = reinterpret_cast<uint8_t*>(&rounded_date);
951 uint8_t reset_byte = (reset_since_rotation ? 1 : 0);
952
953 if (!input_data->Reinitialize(sizeof(rounded_date) + application_id.data_length + 1) ||
954 !input_data->write(serialized_date, sizeof(rounded_date)) ||
955 !input_data->write(application_id.data, application_id.data_length) ||
956 !input_data->write(&reset_byte, 1)) {
957 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
958 }
959 return KM_ERROR_OK;
960 }
961
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)962 keymaster_error_t generate_unique_id(const std::vector<uint8_t>& hbk, uint64_t creation_date_time,
963 const keymaster_blob_t& application_id,
964 bool reset_since_rotation, Buffer* unique_id) {
965 if (unique_id == nullptr) {
966 return KM_ERROR_UNEXPECTED_NULL_POINTER;
967 }
968 HmacSha256 hmac;
969 hmac.Init(hbk.data(), hbk.size());
970
971 Buffer input;
972 keymaster_error_t error =
973 build_unique_id_input(creation_date_time, application_id, reset_since_rotation, &input);
974 if (error != KM_ERROR_OK) {
975 return error;
976 }
977 if (!unique_id->Reinitialize(UNIQUE_ID_SIZE)) {
978 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
979 }
980 hmac.Sign(input.peek_read(), input.available_read(), unique_id->peek_write(),
981 unique_id->available_write());
982 unique_id->advance_write(UNIQUE_ID_SIZE);
983 return KM_ERROR_OK;
984 }
985
986 // Construct an ASN1.1 DER-encoded attestation record containing the values from sw_enforced and
987 // 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)988 keymaster_error_t build_attestation_record(const AuthorizationSet& attestation_params, //
989 AuthorizationSet sw_enforced,
990 AuthorizationSet tee_enforced,
991 const AttestationContext& context,
992 UniquePtr<uint8_t[]>* asn1_key_desc,
993 size_t* asn1_key_desc_len) {
994 ASSERT_OR_RETURN_ERROR(asn1_key_desc && asn1_key_desc_len, KM_ERROR_UNEXPECTED_NULL_POINTER);
995
996 UniquePtr<KM_KEY_DESCRIPTION, KM_KEY_DESCRIPTION_Delete> key_desc(KM_KEY_DESCRIPTION_new());
997 if (!key_desc.get()) return KM_ERROR_MEMORY_ALLOCATION_FAILED;
998
999 KM_ROOT_OF_TRUST* root_of_trust = nullptr;
1000 if (context.GetSecurityLevel() == KM_SECURITY_LEVEL_SOFTWARE) {
1001 key_desc->software_enforced->root_of_trust = KM_ROOT_OF_TRUST_new();
1002 root_of_trust = key_desc->software_enforced->root_of_trust;
1003 } else {
1004 key_desc->tee_enforced->root_of_trust = KM_ROOT_OF_TRUST_new();
1005 root_of_trust = key_desc->tee_enforced->root_of_trust;
1006 }
1007
1008 keymaster_error_t error;
1009 auto vb_params = context.GetVerifiedBootParams(&error);
1010 if (error != KM_ERROR_OK) return error;
1011 if (vb_params->verified_boot_key.data_length &&
1012 !ASN1_OCTET_STRING_set(root_of_trust->verified_boot_key, vb_params->verified_boot_key.data,
1013 vb_params->verified_boot_key.data_length)) {
1014 return TranslateLastOpenSslError();
1015 }
1016 if (vb_params->verified_boot_hash.data_length &&
1017 !ASN1_OCTET_STRING_set(root_of_trust->verified_boot_hash,
1018 vb_params->verified_boot_hash.data,
1019 vb_params->verified_boot_hash.data_length)) {
1020 return TranslateLastOpenSslError();
1021 }
1022
1023 root_of_trust->device_locked = vb_params->device_locked ? 0xFF : 0x00;
1024 if (!ASN1_ENUMERATED_set(root_of_trust->verified_boot_state, vb_params->verified_boot_state)) {
1025 return TranslateLastOpenSslError();
1026 }
1027
1028 if (!ASN1_INTEGER_set(key_desc->attestation_version,
1029 version_to_attestation_version(context.GetKmVersion())) ||
1030 !ASN1_ENUMERATED_set(key_desc->attestation_security_level, context.GetSecurityLevel()) ||
1031 !ASN1_INTEGER_set(key_desc->keymaster_version,
1032 version_to_attestation_km_version(context.GetKmVersion())) ||
1033 !ASN1_ENUMERATED_set(key_desc->keymaster_security_level, context.GetSecurityLevel())) {
1034 return TranslateLastOpenSslError();
1035 }
1036
1037 keymaster_blob_t attestation_challenge = {nullptr, 0};
1038 if (!attestation_params.GetTagValue(TAG_ATTESTATION_CHALLENGE, &attestation_challenge)) {
1039 return KM_ERROR_ATTESTATION_CHALLENGE_MISSING;
1040 }
1041
1042 if (!is_valid_attestation_challenge(attestation_challenge)) {
1043 return KM_ERROR_INVALID_INPUT_LENGTH;
1044 }
1045
1046 if (!ASN1_OCTET_STRING_set(key_desc->attestation_challenge, attestation_challenge.data,
1047 attestation_challenge.data_length)) {
1048 return TranslateLastOpenSslError();
1049 }
1050
1051 keymaster_blob_t attestation_app_id;
1052 if (!attestation_params.GetTagValue(TAG_ATTESTATION_APPLICATION_ID, &attestation_app_id)) {
1053 return KM_ERROR_ATTESTATION_APPLICATION_ID_MISSING;
1054 }
1055 sw_enforced.push_back(TAG_ATTESTATION_APPLICATION_ID, attestation_app_id);
1056
1057 error = context.VerifyAndCopyDeviceIds(
1058 attestation_params,
1059 context.GetSecurityLevel() == KM_SECURITY_LEVEL_SOFTWARE ? &sw_enforced : &tee_enforced);
1060 if (error == KM_ERROR_UNIMPLEMENTED) {
1061 // The KeymasterContext implementation does not support device ID attestation. Bail out if
1062 // device ID attestation is being attempted.
1063 for (const auto& tag : kDeviceAttestationTags) {
1064 if (attestation_params.find(tag) != -1) {
1065 return KM_ERROR_CANNOT_ATTEST_IDS;
1066 }
1067 }
1068 } else if (error != KM_ERROR_OK) {
1069 return error;
1070 }
1071
1072 if (attestation_params.Contains(TAG_DEVICE_UNIQUE_ATTESTATION) &&
1073 context.GetSecurityLevel() == KM_SECURITY_LEVEL_STRONGBOX) {
1074 tee_enforced.push_back(TAG_DEVICE_UNIQUE_ATTESTATION);
1075 };
1076
1077 error = build_auth_list(sw_enforced, key_desc->software_enforced);
1078 if (error != KM_ERROR_OK) return error;
1079
1080 error = build_auth_list(tee_enforced, key_desc->tee_enforced);
1081 if (error != KM_ERROR_OK) return error;
1082
1083 if (attestation_params.GetTagValue(TAG_INCLUDE_UNIQUE_ID)) {
1084 uint64_t creation_datetime;
1085 // Only check sw_enforced for TAG_CREATION_DATETIME, since it shouldn't be in tee_enforced,
1086 // since this implementation has no secure wall clock.
1087 if (!sw_enforced.GetTagValue(TAG_CREATION_DATETIME, &creation_datetime)) {
1088 LOG_E("Unique ID cannot be created without creation datetime", 0);
1089 return KM_ERROR_INVALID_KEY_BLOB;
1090 }
1091
1092 Buffer unique_id = context.GenerateUniqueId(
1093 creation_datetime, attestation_app_id,
1094 attestation_params.GetTagValue(TAG_RESET_SINCE_ID_ROTATION), &error);
1095 if (error != KM_ERROR_OK) return error;
1096
1097 key_desc->unique_id = ASN1_OCTET_STRING_new();
1098 if (!key_desc->unique_id ||
1099 !ASN1_OCTET_STRING_set(key_desc->unique_id, unique_id.peek_read(),
1100 unique_id.available_read()))
1101 return TranslateLastOpenSslError();
1102 }
1103
1104 int len = i2d_KM_KEY_DESCRIPTION(key_desc.get(), nullptr);
1105 if (len < 0) return TranslateLastOpenSslError();
1106 *asn1_key_desc_len = len;
1107 asn1_key_desc->reset(new (std::nothrow) uint8_t[*asn1_key_desc_len]);
1108 if (!asn1_key_desc->get()) return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1109 uint8_t* p = asn1_key_desc->get();
1110 len = i2d_KM_KEY_DESCRIPTION(key_desc.get(), &p);
1111 if (len < 0) return TranslateLastOpenSslError();
1112
1113 return KM_ERROR_OK;
1114 }
1115
1116 // 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)1117 static bool get_repeated_enums(const ASN1_INTEGER_SET* stack, keymaster_tag_t tag,
1118 AuthorizationSet* auth_list) {
1119 ASSERT_OR_RETURN_ERROR(keymaster_tag_get_type(tag) == KM_ENUM_REP, KM_ERROR_INVALID_TAG);
1120 for (size_t i = 0; i < sk_ASN1_INTEGER_num(stack); ++i) {
1121 if (!auth_list->push_back(
1122 keymaster_param_enum(tag, ASN1_INTEGER_get(sk_ASN1_INTEGER_value(stack, i)))))
1123 return false;
1124 }
1125 return true;
1126 }
1127
1128 // Add the specified integer tag/value pair to auth_list.
1129 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)1130 static bool get_enum(const ASN1_INTEGER* asn1_int, TypedEnumTag<Type, Tag, KeymasterEnum> tag,
1131 AuthorizationSet* auth_list) {
1132 if (!asn1_int) return true;
1133 return auth_list->push_back(tag, static_cast<KeymasterEnum>(ASN1_INTEGER_get(asn1_int)));
1134 }
1135
1136 // Add the specified ulong tag/value pair to auth_list.
get_ulong(const ASN1_INTEGER * asn1_int,keymaster_tag_t tag,AuthorizationSet * auth_list)1137 static bool get_ulong(const ASN1_INTEGER* asn1_int, keymaster_tag_t tag,
1138 AuthorizationSet* auth_list) {
1139 if (!asn1_int) return true;
1140 UniquePtr<BIGNUM, BIGNUM_Delete> bn(ASN1_INTEGER_to_BN(asn1_int, nullptr));
1141 if (!bn.get()) return false;
1142 uint64_t ulong = 0;
1143 BN_get_u64(bn.get(), &ulong);
1144 return auth_list->push_back(keymaster_param_long(tag, ulong));
1145 }
1146
1147 // 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)1148 keymaster_error_t extract_auth_list(const KM_AUTH_LIST* record, AuthorizationSet* auth_list) {
1149 if (!record) return KM_ERROR_OK;
1150
1151 // Purpose
1152 if (!get_repeated_enums(record->purpose, TAG_PURPOSE, auth_list)) {
1153 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1154 }
1155
1156 // Algorithm
1157 if (!get_enum(record->algorithm, TAG_ALGORITHM, auth_list)) {
1158 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1159 }
1160
1161 // Key size
1162 if (record->key_size &&
1163 !auth_list->push_back(TAG_KEY_SIZE, ASN1_INTEGER_get(record->key_size))) {
1164 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1165 }
1166
1167 // Block mode
1168 if (!get_repeated_enums(record->block_mode, TAG_BLOCK_MODE, auth_list)) {
1169 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1170 }
1171
1172 // Digest
1173 if (!get_repeated_enums(record->digest, TAG_DIGEST, auth_list)) {
1174 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1175 }
1176
1177 // Padding
1178 if (!get_repeated_enums(record->padding, TAG_PADDING, auth_list)) {
1179 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1180 }
1181
1182 // Caller nonce
1183 if (record->caller_nonce && !auth_list->push_back(TAG_CALLER_NONCE)) {
1184 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1185 }
1186
1187 // Min mac length
1188 if (!get_ulong(record->min_mac_length, TAG_MIN_MAC_LENGTH, auth_list)) {
1189 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1190 }
1191
1192 // EC curve
1193 if (!get_enum(record->ec_curve, TAG_EC_CURVE, auth_list)) {
1194 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1195 }
1196
1197 // RSA public exponent
1198 if (!get_ulong(record->rsa_public_exponent, TAG_RSA_PUBLIC_EXPONENT, auth_list)) {
1199 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1200 }
1201
1202 // Rsa Oaep Mgf Digest
1203 if (!get_repeated_enums(record->mgf_digest, TAG_RSA_OAEP_MGF_DIGEST, auth_list)) {
1204 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1205 }
1206
1207 // Rollback resistance
1208 if (record->rollback_resistance && !auth_list->push_back(TAG_ROLLBACK_RESISTANCE)) {
1209 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1210 }
1211
1212 // Early boot only
1213 if (record->early_boot_only && !auth_list->push_back(TAG_EARLY_BOOT_ONLY)) {
1214 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1215 }
1216
1217 // Active date time
1218 if (!get_ulong(record->active_date_time, TAG_ACTIVE_DATETIME, auth_list)) {
1219 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1220 }
1221
1222 // Origination expire date time
1223 if (!get_ulong(record->origination_expire_date_time, TAG_ORIGINATION_EXPIRE_DATETIME,
1224 auth_list)) {
1225 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1226 }
1227
1228 // Usage Expire date time
1229 if (!get_ulong(record->usage_expire_date_time, TAG_USAGE_EXPIRE_DATETIME, auth_list)) {
1230 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1231 }
1232
1233 // Usage count limit
1234 if (record->usage_count_limit &&
1235 !auth_list->push_back(TAG_USAGE_COUNT_LIMIT, ASN1_INTEGER_get(record->usage_count_limit))) {
1236 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1237 }
1238
1239 // No auth required
1240 if (record->no_auth_required && !auth_list->push_back(TAG_NO_AUTH_REQUIRED)) {
1241 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1242 }
1243
1244 // User auth type
1245 if (!get_enum(record->user_auth_type, TAG_USER_AUTH_TYPE, auth_list)) {
1246 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1247 }
1248
1249 // Auth timeout
1250 if (record->auth_timeout &&
1251 !auth_list->push_back(TAG_AUTH_TIMEOUT, ASN1_INTEGER_get(record->auth_timeout))) {
1252 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1253 }
1254
1255 // Allow while on body
1256 if (record->allow_while_on_body && !auth_list->push_back(TAG_ALLOW_WHILE_ON_BODY)) {
1257 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1258 }
1259
1260 // trusted user presence required
1261 if (record->trusted_user_presence_required &&
1262 !auth_list->push_back(TAG_TRUSTED_USER_PRESENCE_REQUIRED)) {
1263 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1264 }
1265
1266 // trusted confirmation required
1267 if (record->trusted_confirmation_required &&
1268 !auth_list->push_back(TAG_TRUSTED_CONFIRMATION_REQUIRED)) {
1269 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1270 }
1271
1272 // Unlocked device required
1273 if (record->unlocked_device_required && !auth_list->push_back(TAG_UNLOCKED_DEVICE_REQUIRED)) {
1274 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1275 }
1276
1277 // All applications
1278 if (record->all_applications && !auth_list->push_back(TAG_ALL_APPLICATIONS)) {
1279 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1280 }
1281
1282 // Application ID
1283 if (record->application_id &&
1284 !auth_list->push_back(TAG_APPLICATION_ID, record->application_id->data,
1285 record->application_id->length)) {
1286 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1287 }
1288
1289 // Creation date time
1290 if (!get_ulong(record->creation_date_time, TAG_CREATION_DATETIME, auth_list)) {
1291 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1292 }
1293
1294 // Origin
1295 if (!get_enum(record->origin, TAG_ORIGIN, auth_list)) {
1296 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1297 }
1298
1299 // Rollback resistant
1300 if (record->rollback_resistant && !auth_list->push_back(TAG_ROLLBACK_RESISTANT)) {
1301 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1302 }
1303
1304 // Root of trust
1305 if (record->root_of_trust) {
1306 KM_ROOT_OF_TRUST* rot = record->root_of_trust;
1307 if (!rot->verified_boot_key) return KM_ERROR_INVALID_KEY_BLOB;
1308
1309 // Other root of trust fields are not mapped to auth set entries.
1310 }
1311
1312 // OS Version
1313 if (record->os_version &&
1314 !auth_list->push_back(TAG_OS_VERSION, ASN1_INTEGER_get(record->os_version))) {
1315 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1316 }
1317
1318 // OS Patch level
1319 if (record->os_patchlevel &&
1320 !auth_list->push_back(TAG_OS_PATCHLEVEL, ASN1_INTEGER_get(record->os_patchlevel))) {
1321 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1322 }
1323
1324 // attestation application Id
1325 if (record->attestation_application_id &&
1326 !auth_list->push_back(TAG_ATTESTATION_APPLICATION_ID,
1327 record->attestation_application_id->data,
1328 record->attestation_application_id->length)) {
1329 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1330 }
1331
1332 // Brand name
1333 if (record->attestation_id_brand &&
1334 !auth_list->push_back(TAG_ATTESTATION_ID_BRAND, record->attestation_id_brand->data,
1335 record->attestation_id_brand->length)) {
1336 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1337 }
1338
1339 // Device name
1340 if (record->attestation_id_device &&
1341 !auth_list->push_back(TAG_ATTESTATION_ID_DEVICE, record->attestation_id_device->data,
1342 record->attestation_id_device->length)) {
1343 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1344 }
1345
1346 // Product name
1347 if (record->attestation_id_product &&
1348 !auth_list->push_back(TAG_ATTESTATION_ID_PRODUCT, record->attestation_id_product->data,
1349 record->attestation_id_product->length)) {
1350 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1351 }
1352
1353 // Serial number
1354 if (record->attestation_id_serial &&
1355 !auth_list->push_back(TAG_ATTESTATION_ID_SERIAL, record->attestation_id_serial->data,
1356 record->attestation_id_serial->length)) {
1357 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1358 }
1359
1360 // IMEI
1361 if (record->attestation_id_imei &&
1362 !auth_list->push_back(TAG_ATTESTATION_ID_IMEI, record->attestation_id_imei->data,
1363 record->attestation_id_imei->length)) {
1364 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1365 }
1366
1367 // MEID
1368 if (record->attestation_id_meid &&
1369 !auth_list->push_back(TAG_ATTESTATION_ID_MEID, record->attestation_id_meid->data,
1370 record->attestation_id_meid->length)) {
1371 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1372 }
1373
1374 // Manufacturer name
1375 if (record->attestation_id_manufacturer &&
1376 !auth_list->push_back(TAG_ATTESTATION_ID_MANUFACTURER,
1377 record->attestation_id_manufacturer->data,
1378 record->attestation_id_manufacturer->length)) {
1379 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1380 }
1381
1382 // Model name
1383 if (record->attestation_id_model &&
1384 !auth_list->push_back(TAG_ATTESTATION_ID_MODEL, record->attestation_id_model->data,
1385 record->attestation_id_model->length)) {
1386 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1387 }
1388
1389 // vendor patch level
1390 if (record->vendor_patchlevel &&
1391 !auth_list->push_back(TAG_VENDOR_PATCHLEVEL, ASN1_INTEGER_get(record->vendor_patchlevel))) {
1392 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1393 }
1394
1395 // boot patch level
1396 if (record->boot_patch_level &&
1397 !auth_list->push_back(TAG_BOOT_PATCHLEVEL, ASN1_INTEGER_get(record->boot_patch_level))) {
1398 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1399 }
1400
1401 // device unique attestation
1402 if (record->device_unique_attestation && !auth_list->push_back(TAG_DEVICE_UNIQUE_ATTESTATION)) {
1403 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1404 }
1405
1406 // identity credential key
1407 if (record->identity_credential_key && !auth_list->push_back(TAG_IDENTITY_CREDENTIAL_KEY)) {
1408 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1409 }
1410
1411 // Second IMEI
1412 if (record->attestation_id_second_imei &&
1413 !auth_list->push_back(TAG_ATTESTATION_ID_SECOND_IMEI,
1414 record->attestation_id_second_imei->data,
1415 record->attestation_id_second_imei->length)) {
1416 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1417 }
1418
1419 return KM_ERROR_OK;
1420 }
1421
1422 // Parse the DER-encoded attestation record, placing the results in keymaster_version,
1423 // 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)1424 keymaster_error_t parse_attestation_record(const uint8_t* asn1_key_desc, size_t asn1_key_desc_len,
1425 uint32_t* attestation_version, //
1426 keymaster_security_level_t* attestation_security_level,
1427 uint32_t* keymaster_version,
1428 keymaster_security_level_t* keymaster_security_level,
1429 keymaster_blob_t* attestation_challenge,
1430 AuthorizationSet* software_enforced,
1431 AuthorizationSet* tee_enforced,
1432 keymaster_blob_t* unique_id) {
1433 const uint8_t* p = asn1_key_desc;
1434 UniquePtr<KM_KEY_DESCRIPTION, KM_KEY_DESCRIPTION_Delete> record(
1435 d2i_KM_KEY_DESCRIPTION(nullptr, &p, asn1_key_desc_len));
1436 if (!record.get()) return TranslateLastOpenSslError();
1437
1438 *attestation_version = ASN1_INTEGER_get(record->attestation_version);
1439 *attestation_security_level = static_cast<keymaster_security_level_t>(
1440 ASN1_ENUMERATED_get(record->attestation_security_level));
1441 *keymaster_version = ASN1_INTEGER_get(record->keymaster_version);
1442 *keymaster_security_level = static_cast<keymaster_security_level_t>(
1443 ASN1_ENUMERATED_get(record->keymaster_security_level));
1444
1445 attestation_challenge->data =
1446 dup_buffer(record->attestation_challenge->data, record->attestation_challenge->length);
1447 attestation_challenge->data_length = record->attestation_challenge->length;
1448
1449 unique_id->data = dup_buffer(record->unique_id->data, record->unique_id->length);
1450 unique_id->data_length = record->unique_id->length;
1451
1452 keymaster_error_t error = extract_auth_list(record->software_enforced, software_enforced);
1453 if (error != KM_ERROR_OK) return error;
1454
1455 return extract_auth_list(record->tee_enforced, tee_enforced);
1456 }
1457
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)1458 keymaster_error_t parse_root_of_trust(const uint8_t* asn1_key_desc, size_t asn1_key_desc_len,
1459 keymaster_blob_t* verified_boot_key,
1460 keymaster_verified_boot_t* verified_boot_state,
1461 bool* device_locked) {
1462 const uint8_t* p = asn1_key_desc;
1463 UniquePtr<KM_KEY_DESCRIPTION, KM_KEY_DESCRIPTION_Delete> record(
1464 d2i_KM_KEY_DESCRIPTION(nullptr, &p, asn1_key_desc_len));
1465 if (!record.get()) {
1466 return TranslateLastOpenSslError();
1467 }
1468 if (!record->tee_enforced) {
1469 return KM_ERROR_INVALID_ARGUMENT;
1470 }
1471 if (!record->tee_enforced->root_of_trust) {
1472 return KM_ERROR_INVALID_ARGUMENT;
1473 }
1474 if (!record->tee_enforced->root_of_trust->verified_boot_key) {
1475 return KM_ERROR_INVALID_ARGUMENT;
1476 }
1477 KM_ROOT_OF_TRUST* root_of_trust = record->tee_enforced->root_of_trust;
1478 verified_boot_key->data = dup_buffer(root_of_trust->verified_boot_key->data,
1479 root_of_trust->verified_boot_key->length);
1480 verified_boot_key->data_length = root_of_trust->verified_boot_key->length;
1481 *verified_boot_state = static_cast<keymaster_verified_boot_t>(
1482 ASN1_ENUMERATED_get(root_of_trust->verified_boot_state));
1483 *device_locked = root_of_trust->device_locked;
1484 return KM_ERROR_OK;
1485 }
1486
1487 // Parse the EAT-encoded attestation record, placing the results in keymaster_version,
1488 // 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)1489 keymaster_error_t parse_eat_record(
1490 const uint8_t* eat_key_desc, size_t eat_key_desc_len, uint32_t* attestation_version,
1491 keymaster_security_level_t* attestation_security_level, uint32_t* keymaster_version,
1492 keymaster_security_level_t* keymaster_security_level, keymaster_blob_t* attestation_challenge,
1493 AuthorizationSet* software_enforced, AuthorizationSet* tee_enforced,
1494 keymaster_blob_t* unique_id, keymaster_blob_t* verified_boot_key,
1495 keymaster_verified_boot_t* verified_boot_state, bool* device_locked,
1496 std::vector<int64_t>* unexpected_claims) {
1497 auto [top_level_item, next_pos, error] = cppbor::parse(eat_key_desc, eat_key_desc_len);
1498 ASSERT_OR_RETURN_ERROR(top_level_item, KM_ERROR_INVALID_TAG);
1499 const cppbor::Map* eat_map = top_level_item->asMap();
1500 ASSERT_OR_RETURN_ERROR(eat_map, KM_ERROR_INVALID_TAG);
1501 bool verified_or_self_signed = false;
1502
1503 for (size_t i = 0; i < eat_map->size(); i++) {
1504 auto& [key_item, value_item] = (*eat_map)[i];
1505 const cppbor::Int* key = key_item->asInt();
1506 ASSERT_OR_RETURN_ERROR(key, (KM_ERROR_INVALID_TAG));
1507
1508 // The following values will either hold the typed value, or be null (if not the right
1509 // type).
1510 const cppbor::Int* int_value = value_item->asInt();
1511 const cppbor::Bstr* bstr_value = value_item->asBstr();
1512 const cppbor::Simple* simple_value = value_item->asSimple();
1513 const cppbor::Array* array_value = value_item->asArray();
1514 const cppbor::Map* map_value = value_item->asMap();
1515
1516 keymaster_error_t error;
1517 switch ((EatClaim)key->value()) {
1518 default:
1519 unexpected_claims->push_back(key->value());
1520 break;
1521 case EatClaim::ATTESTATION_VERSION:
1522 ASSERT_OR_RETURN_ERROR(int_value, KM_ERROR_INVALID_TAG);
1523 *attestation_version = int_value->value();
1524 break;
1525 case EatClaim::SECURITY_LEVEL:
1526 ASSERT_OR_RETURN_ERROR(int_value, KM_ERROR_INVALID_TAG);
1527 switch ((EatSecurityLevel)int_value->value()) {
1528 // TODO: Is my assumption correct that the security level of the attestation data should
1529 // always be equal to the security level of keymint, as the attestation data always
1530 // lives in the top-level module?
1531 case EatSecurityLevel::UNRESTRICTED:
1532 *keymaster_security_level = *attestation_security_level =
1533 KM_SECURITY_LEVEL_SOFTWARE;
1534 break;
1535 case EatSecurityLevel::SECURE_RESTRICTED:
1536 *keymaster_security_level = *attestation_security_level =
1537 KM_SECURITY_LEVEL_TRUSTED_ENVIRONMENT;
1538 break;
1539 case EatSecurityLevel::HARDWARE:
1540 *keymaster_security_level = *attestation_security_level =
1541 KM_SECURITY_LEVEL_STRONGBOX;
1542 break;
1543 default:
1544 return KM_ERROR_INVALID_TAG;
1545 }
1546 break;
1547 case EatClaim::KEYMASTER_VERSION:
1548 ASSERT_OR_RETURN_ERROR(int_value, KM_ERROR_INVALID_TAG);
1549 *keymaster_version = int_value->value();
1550 break;
1551 case EatClaim::SUBMODS:
1552 ASSERT_OR_RETURN_ERROR(map_value, KM_ERROR_INVALID_TAG);
1553 for (size_t j = 0; j < map_value->size(); j++) {
1554 auto& [submod_key, submod_value] = (*map_value)[j];
1555 const cppbor::Map* submod_map = submod_value->asMap();
1556 ASSERT_OR_RETURN_ERROR(submod_map, KM_ERROR_INVALID_TAG);
1557 error = parse_eat_submod(submod_map, software_enforced, tee_enforced);
1558 if (error != KM_ERROR_OK) return error;
1559 }
1560 break;
1561 case EatClaim::CTI:
1562 error = bstr_to_blob(bstr_value, unique_id);
1563 if (error != KM_ERROR_OK) return error;
1564 break;
1565 case EatClaim::NONCE:
1566 error = bstr_to_blob(bstr_value, attestation_challenge);
1567 if (error != KM_ERROR_OK) return error;
1568 break;
1569 case EatClaim::VERIFIED_BOOT_KEY:
1570 error = bstr_to_blob(bstr_value, verified_boot_key);
1571 if (error != KM_ERROR_OK) return error;
1572 break;
1573 case EatClaim::VERIFIED_BOOT_HASH:
1574 // Not parsing this for now.
1575 break;
1576 case EatClaim::DEVICE_UNIQUE_ATTESTATION:
1577 if (value_item->asSimple() == nullptr || !value_item->asSimple()->asBool()->value()) {
1578 return KM_ERROR_INVALID_TAG;
1579 }
1580 // Not parsing this for now.
1581 break;
1582 case EatClaim::DEVICE_LOCKED:
1583 ASSERT_OR_RETURN_ERROR(simple_value->asBool(), KM_ERROR_INVALID_TAG);
1584 *device_locked = simple_value->asBool()->value();
1585 break;
1586 case EatClaim::BOOT_STATE:
1587 ASSERT_OR_RETURN_ERROR(array_value, KM_ERROR_INVALID_TAG);
1588 ASSERT_OR_RETURN_ERROR(array_value->size() == 5, KM_ERROR_INVALID_TAG);
1589 ASSERT_OR_RETURN_ERROR((*array_value)[4]->asSimple()->asBool()->value() == false,
1590 KM_ERROR_INVALID_TAG);
1591 verified_or_self_signed = (*array_value)[0]->asSimple()->asBool()->value();
1592 ASSERT_OR_RETURN_ERROR(verified_or_self_signed ==
1593 (*array_value)[1]->asSimple()->asBool()->value(),
1594 KM_ERROR_INVALID_TAG);
1595 ASSERT_OR_RETURN_ERROR(verified_or_self_signed ==
1596 (*array_value)[2]->asSimple()->asBool()->value(),
1597 KM_ERROR_INVALID_TAG);
1598 ASSERT_OR_RETURN_ERROR(verified_or_self_signed ==
1599 (*array_value)[3]->asSimple()->asBool()->value(),
1600 KM_ERROR_INVALID_TAG);
1601 break;
1602 case EatClaim::OFFICIAL_BUILD:
1603 *verified_boot_state = KM_VERIFIED_BOOT_VERIFIED;
1604 break;
1605 }
1606 }
1607
1608 if (*verified_boot_state == KM_VERIFIED_BOOT_VERIFIED) {
1609 (void)(verified_boot_state);
1610 // TODO: re-enable this
1611 // ASSERT_OR_RETURN_ERROR(verified_or_self_signed, KM_ERROR_INVALID_TAG);
1612 } else {
1613 *verified_boot_state =
1614 verified_or_self_signed ? KM_VERIFIED_BOOT_SELF_SIGNED : KM_VERIFIED_BOOT_UNVERIFIED;
1615 }
1616
1617 return KM_ERROR_OK;
1618 }
1619
parse_submod_values(AuthorizationSetBuilder * set_builder,int * auth_set_security_level,const cppbor::Map * submod_map)1620 keymaster_error_t parse_submod_values(AuthorizationSetBuilder* set_builder,
1621 int* auth_set_security_level, const cppbor::Map* submod_map) {
1622 ASSERT_OR_RETURN_ERROR(set_builder, KM_ERROR_UNEXPECTED_NULL_POINTER);
1623 for (size_t i = 0; i < submod_map->size(); i++) {
1624 auto& [key_item, value_item] = (*submod_map)[i];
1625 const cppbor::Int* key_int = key_item->asInt();
1626 ASSERT_OR_RETURN_ERROR(key_int, KM_ERROR_INVALID_TAG);
1627 int key = key_int->value();
1628 keymaster_error_t error;
1629 keymaster_blob_t blob;
1630
1631 switch ((EatClaim)key) {
1632 default:
1633 return KM_ERROR_INVALID_TAG;
1634 case EatClaim::ALGORITHM:
1635 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1636 set_builder->Authorization(
1637 TAG_ALGORITHM, static_cast<keymaster_algorithm_t>(value_item->asInt()->value()));
1638 break;
1639 case EatClaim::EC_CURVE:
1640 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1641 set_builder->Authorization(
1642 TAG_EC_CURVE, static_cast<keymaster_ec_curve_t>(value_item->asInt()->value()));
1643 break;
1644 case EatClaim::USER_AUTH_TYPE:
1645 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1646 set_builder->Authorization(TAG_USER_AUTH_TYPE, static_cast<hw_authenticator_type_t>(
1647 value_item->asInt()->value()));
1648 break;
1649 case EatClaim::ORIGIN:
1650 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1651 set_builder->Authorization(
1652 TAG_ORIGIN, static_cast<keymaster_key_origin_t>(value_item->asInt()->value()));
1653 break;
1654 case EatClaim::PURPOSE:
1655 for (size_t j = 0; j < value_item->asArray()->size(); j++) {
1656 set_builder->Authorization(TAG_PURPOSE,
1657 static_cast<keymaster_purpose_t>(
1658 (*value_item->asArray())[j]->asInt()->value()));
1659 }
1660 break;
1661 case EatClaim::PADDING:
1662 for (size_t j = 0; j < value_item->asArray()->size(); j++) {
1663 set_builder->Authorization(TAG_PADDING,
1664 static_cast<keymaster_padding_t>(
1665 (*value_item->asArray())[j]->asInt()->value()));
1666 }
1667 break;
1668 case EatClaim::DIGEST:
1669 for (size_t j = 0; j < value_item->asArray()->size(); j++) {
1670 set_builder->Authorization(
1671 TAG_DIGEST,
1672 static_cast<keymaster_digest_t>((*value_item->asArray())[j]->asInt()->value()));
1673 }
1674 break;
1675 case EatClaim::BLOCK_MODE:
1676 for (size_t j = 0; j < value_item->asArray()->size(); j++) {
1677 set_builder->Authorization(TAG_BLOCK_MODE,
1678 static_cast<keymaster_block_mode_t>(
1679 (*value_item->asArray())[j]->asInt()->value()));
1680 }
1681 break;
1682 case EatClaim::KEY_SIZE:
1683 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1684 set_builder->Authorization(TAG_KEY_SIZE, value_item->asInt()->value());
1685 break;
1686 case EatClaim::AUTH_TIMEOUT:
1687 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1688 set_builder->Authorization(TAG_AUTH_TIMEOUT, value_item->asInt()->value());
1689 break;
1690 case EatClaim::OS_VERSION:
1691 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1692 set_builder->Authorization(TAG_OS_VERSION, value_item->asInt()->value());
1693 break;
1694 case EatClaim::OS_PATCHLEVEL:
1695 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1696 set_builder->Authorization(TAG_OS_PATCHLEVEL, value_item->asInt()->value());
1697 break;
1698 case EatClaim::MIN_MAC_LENGTH:
1699 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1700 set_builder->Authorization(TAG_MIN_MAC_LENGTH, value_item->asInt()->value());
1701 break;
1702 case EatClaim::BOOT_PATCHLEVEL:
1703 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1704 set_builder->Authorization(TAG_BOOT_PATCHLEVEL, value_item->asInt()->value());
1705 break;
1706 case EatClaim::VENDOR_PATCHLEVEL:
1707 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1708 set_builder->Authorization(TAG_VENDOR_PATCHLEVEL, value_item->asInt()->value());
1709 break;
1710 case EatClaim::RSA_PUBLIC_EXPONENT:
1711 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1712 set_builder->Authorization(TAG_RSA_PUBLIC_EXPONENT, value_item->asInt()->value());
1713 break;
1714 case EatClaim::ACTIVE_DATETIME:
1715 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1716 set_builder->Authorization(TAG_ACTIVE_DATETIME, value_item->asInt()->value());
1717 break;
1718 case EatClaim::ORIGINATION_EXPIRE_DATETIME:
1719 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1720 set_builder->Authorization(TAG_ORIGINATION_EXPIRE_DATETIME,
1721 value_item->asInt()->value());
1722 break;
1723 case EatClaim::USAGE_EXPIRE_DATETIME:
1724 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1725 set_builder->Authorization(TAG_USAGE_EXPIRE_DATETIME, value_item->asInt()->value());
1726 break;
1727 case EatClaim::IAT:
1728 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1729 set_builder->Authorization(TAG_CREATION_DATETIME, value_item->asInt()->value());
1730 break;
1731 case EatClaim::NO_AUTH_REQUIRED:
1732 if (value_item->asSimple() == nullptr || !value_item->asSimple()->asBool()->value()) {
1733 return KM_ERROR_INVALID_TAG;
1734 }
1735 set_builder->Authorization(TAG_NO_AUTH_REQUIRED);
1736 break;
1737 case EatClaim::ALL_APPLICATIONS:
1738 if (value_item->asSimple() == nullptr || !value_item->asSimple()->asBool()->value()) {
1739 return KM_ERROR_INVALID_TAG;
1740 }
1741 set_builder->Authorization(TAG_ALL_APPLICATIONS);
1742 break;
1743 case EatClaim::ROLLBACK_RESISTANT:
1744 if (value_item->asSimple() == nullptr || !value_item->asSimple()->asBool()->value()) {
1745 return KM_ERROR_INVALID_TAG;
1746 }
1747 set_builder->Authorization(TAG_ROLLBACK_RESISTANT);
1748 break;
1749 case EatClaim::ALLOW_WHILE_ON_BODY:
1750 if (value_item->asSimple() == nullptr || !value_item->asSimple()->asBool()->value()) {
1751 return KM_ERROR_INVALID_TAG;
1752 }
1753 set_builder->Authorization(TAG_ALLOW_WHILE_ON_BODY);
1754 break;
1755 case EatClaim::UNLOCKED_DEVICE_REQUIRED:
1756 if (value_item->asSimple() == nullptr || !value_item->asSimple()->asBool()->value()) {
1757 return KM_ERROR_INVALID_TAG;
1758 }
1759 set_builder->Authorization(TAG_UNLOCKED_DEVICE_REQUIRED);
1760 break;
1761 case EatClaim::CALLER_NONCE:
1762 if (value_item->asSimple() == nullptr || !value_item->asSimple()->asBool()->value()) {
1763 return KM_ERROR_INVALID_TAG;
1764 }
1765 set_builder->Authorization(TAG_CALLER_NONCE);
1766 break;
1767 case EatClaim::TRUSTED_CONFIRMATION_REQUIRED:
1768 if (value_item->asSimple() == nullptr || !value_item->asSimple()->asBool()->value()) {
1769 return KM_ERROR_INVALID_TAG;
1770 }
1771 set_builder->Authorization(TAG_TRUSTED_CONFIRMATION_REQUIRED);
1772 break;
1773 case EatClaim::EARLY_BOOT_ONLY:
1774 if (value_item->asSimple() == nullptr || !value_item->asSimple()->asBool()->value()) {
1775 return KM_ERROR_INVALID_TAG;
1776 }
1777 set_builder->Authorization(TAG_EARLY_BOOT_ONLY);
1778 break;
1779 case EatClaim::IDENTITY_CREDENTIAL_KEY:
1780 if (value_item->asSimple() == nullptr || !value_item->asSimple()->asBool()->value()) {
1781 return KM_ERROR_INVALID_TAG;
1782 }
1783 set_builder->Authorization(TAG_IDENTITY_CREDENTIAL_KEY);
1784 break;
1785 case EatClaim::STORAGE_KEY:
1786 if (value_item->asSimple() == nullptr || !value_item->asSimple()->asBool()->value()) {
1787 return KM_ERROR_INVALID_TAG;
1788 }
1789 set_builder->Authorization(TAG_STORAGE_KEY);
1790 break;
1791 case EatClaim::TRUSTED_USER_PRESENCE_REQUIRED:
1792 if (value_item->asSimple() == nullptr || !value_item->asSimple()->asBool()->value()) {
1793 return KM_ERROR_INVALID_TAG;
1794 }
1795 set_builder->Authorization(TAG_TRUSTED_USER_PRESENCE_REQUIRED);
1796 break;
1797 case EatClaim::DEVICE_UNIQUE_ATTESTATION:
1798 if (value_item->asSimple() == nullptr || !value_item->asSimple()->asBool()->value()) {
1799 return KM_ERROR_INVALID_TAG;
1800 }
1801 set_builder->Authorization(TAG_DEVICE_UNIQUE_ATTESTATION);
1802 break;
1803 case EatClaim::APPLICATION_ID:
1804 error = bstr_to_blob(value_item->asBstr(), &blob);
1805 if (error != KM_ERROR_OK) return error;
1806 set_builder->Authorization(TAG_APPLICATION_ID, blob);
1807 break;
1808 case EatClaim::ATTESTATION_APPLICATION_ID:
1809 error = bstr_to_blob(value_item->asBstr(), &blob);
1810 if (error != KM_ERROR_OK) return error;
1811 set_builder->Authorization(TAG_ATTESTATION_APPLICATION_ID, blob);
1812 break;
1813 case EatClaim::ATTESTATION_ID_BRAND:
1814 error = bstr_to_blob(value_item->asBstr(), &blob);
1815 if (error != KM_ERROR_OK) return error;
1816 set_builder->Authorization(TAG_ATTESTATION_ID_BRAND, blob);
1817 break;
1818 case EatClaim::ATTESTATION_ID_DEVICE:
1819 error = bstr_to_blob(value_item->asBstr(), &blob);
1820 if (error != KM_ERROR_OK) return error;
1821 set_builder->Authorization(TAG_ATTESTATION_ID_DEVICE, blob);
1822 break;
1823 case EatClaim::ATTESTATION_ID_PRODUCT:
1824 error = bstr_to_blob(value_item->asBstr(), &blob);
1825 if (error != KM_ERROR_OK) return error;
1826 set_builder->Authorization(TAG_ATTESTATION_ID_PRODUCT, blob);
1827 break;
1828 case EatClaim::ATTESTATION_ID_SERIAL:
1829 error = bstr_to_blob(value_item->asBstr(), &blob);
1830 if (error != KM_ERROR_OK) return error;
1831 set_builder->Authorization(TAG_ATTESTATION_ID_SERIAL, blob);
1832 break;
1833 case EatClaim::UEID:
1834 error = ueid_to_imei_blob(value_item->asBstr(), &blob);
1835 if (error != KM_ERROR_OK) return error;
1836 set_builder->Authorization(TAG_ATTESTATION_ID_IMEI, blob);
1837 break;
1838 case EatClaim::ATTESTATION_ID_MEID:
1839 error = bstr_to_blob(value_item->asBstr(), &blob);
1840 if (error != KM_ERROR_OK) return error;
1841 set_builder->Authorization(TAG_ATTESTATION_ID_MEID, blob);
1842 break;
1843 case EatClaim::ATTESTATION_ID_MANUFACTURER:
1844 error = bstr_to_blob(value_item->asBstr(), &blob);
1845 if (error != KM_ERROR_OK) return error;
1846 set_builder->Authorization(TAG_ATTESTATION_ID_MANUFACTURER, blob);
1847 break;
1848 case EatClaim::ATTESTATION_ID_MODEL:
1849 error = bstr_to_blob(value_item->asBstr(), &blob);
1850 if (error != KM_ERROR_OK) return error;
1851 set_builder->Authorization(TAG_ATTESTATION_ID_MODEL, blob);
1852 break;
1853 case EatClaim::CONFIRMATION_TOKEN:
1854 error = bstr_to_blob(value_item->asBstr(), &blob);
1855 if (error != KM_ERROR_OK) return error;
1856 set_builder->Authorization(TAG_CONFIRMATION_TOKEN, blob);
1857 break;
1858 case EatClaim::SECURITY_LEVEL:
1859 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1860 *auth_set_security_level = value_item->asInt()->value();
1861 }
1862 }
1863
1864 return KM_ERROR_OK;
1865 }
1866
parse_eat_submod(const cppbor::Map * submod_values,AuthorizationSet * software_enforced,AuthorizationSet * tee_enforced)1867 keymaster_error_t parse_eat_submod(const cppbor::Map* submod_values,
1868 AuthorizationSet* software_enforced,
1869 AuthorizationSet* tee_enforced) {
1870 AuthorizationSetBuilder auth_set_builder;
1871 int auth_set_security_level = 0;
1872 keymaster_error_t error =
1873 parse_submod_values(&auth_set_builder, &auth_set_security_level, submod_values);
1874 if (error) return error;
1875 switch ((EatSecurityLevel)auth_set_security_level) {
1876 case EatSecurityLevel::HARDWARE:
1877 // Hardware attestation should never occur in a submod of another EAT.
1878 [[fallthrough]];
1879 default:
1880 return KM_ERROR_INVALID_TAG;
1881 case EatSecurityLevel::UNRESTRICTED:
1882 *software_enforced = AuthorizationSet(auth_set_builder);
1883 break;
1884 case EatSecurityLevel::SECURE_RESTRICTED:
1885 *tee_enforced = AuthorizationSet(auth_set_builder);
1886 break;
1887 }
1888
1889 return KM_ERROR_OK;
1890 }
1891 } // namespace keymaster
1892