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, KM_TAG_ATTESTATION_ID_PRODUCT,
51 KM_TAG_ATTESTATION_ID_SERIAL, KM_TAG_ATTESTATION_ID_IMEI, KM_TAG_ATTESTATION_ID_MEID,
52 KM_TAG_ATTESTATION_ID_MANUFACTURER, KM_TAG_ATTESTATION_ID_MODEL,
53 };
54
55 struct KM_AUTH_LIST_Delete {
operator ()keymaster::KM_AUTH_LIST_Delete56 void operator()(KM_AUTH_LIST* p) { KM_AUTH_LIST_free(p); }
57 };
58
59 struct KM_KEY_DESCRIPTION_Delete {
operator ()keymaster::KM_KEY_DESCRIPTION_Delete60 void operator()(KM_KEY_DESCRIPTION* p) { KM_KEY_DESCRIPTION_free(p); }
61 };
62
63 struct KM_ROOT_OF_TRUST_Delete {
operator ()keymaster::KM_ROOT_OF_TRUST_Delete64 void operator()(KM_ROOT_OF_TRUST* p) { KM_ROOT_OF_TRUST_free(p); }
65 };
66
blob_to_bstr(const keymaster_blob_t & blob)67 static cppbor::Bstr blob_to_bstr(const keymaster_blob_t& blob) {
68 return cppbor::Bstr(std::pair(blob.data, blob.data_length));
69 }
70
bstr_to_blob(const cppbor::Bstr * bstr,keymaster_blob_t * blob)71 static keymaster_error_t bstr_to_blob(const cppbor::Bstr* bstr, keymaster_blob_t* blob) {
72 ASSERT_OR_RETURN_ERROR(bstr, KM_ERROR_INVALID_TAG);
73 const std::vector<uint8_t>& vec = bstr->value();
74 uint8_t* data = (uint8_t*)calloc(vec.size(), sizeof(uint8_t));
75 if (data == nullptr) {
76 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
77 }
78
79 std::copy(vec.begin(), vec.end(), data);
80 blob->data = data;
81 blob->data_length = vec.size();
82
83 return KM_ERROR_OK;
84 }
85
get_uint32_value(const keymaster_key_param_t & param)86 static uint32_t get_uint32_value(const keymaster_key_param_t& param) {
87 switch (keymaster_tag_get_type(param.tag)) {
88 case KM_ENUM:
89 case KM_ENUM_REP:
90 return param.enumerated;
91 case KM_UINT:
92 case KM_UINT_REP:
93 return param.integer;
94 default:
95 ASSERT_OR_RETURN_ERROR(false, 0xFFFFFFFF);
96 }
97 }
98
get_uint32_value(EatSecurityLevel level)99 static int64_t get_uint32_value(EatSecurityLevel level) {
100 return static_cast<int64_t>(level);
101 }
102
103 // 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)104 static keymaster_error_t insert_integer(ASN1_INTEGER* value, ASN1_INTEGER** dest_integer,
105 ASN1_INTEGER_SET** dest_integer_set) {
106 ASSERT_OR_RETURN_ERROR((dest_integer == nullptr) ^ (dest_integer_set == nullptr),
107 KM_ERROR_UNEXPECTED_NULL_POINTER);
108 ASSERT_OR_RETURN_ERROR(value, KM_ERROR_INVALID_ARGUMENT);
109
110 if (dest_integer_set) {
111 if (!*dest_integer_set) {
112 *dest_integer_set = sk_ASN1_INTEGER_new_null();
113 }
114 if (!*dest_integer_set) {
115 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
116 }
117 if (!sk_ASN1_INTEGER_push(*dest_integer_set, value)) {
118 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
119 }
120 return KM_ERROR_OK;
121
122 } else if (dest_integer) {
123 if (*dest_integer) {
124 ASN1_INTEGER_free(*dest_integer);
125 }
126 *dest_integer = value;
127 return KM_ERROR_OK;
128 }
129
130 ASSERT_OR_RETURN_ERROR(false, KM_ERROR_UNKNOWN_ERROR); // Should never get here.
131 }
132
133 // 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)134 static void add_repeating_enum(EatClaim key, uint32_t value,
135 std::unordered_map<EatClaim, cppbor::Array>* fields_map) {
136 auto field = fields_map->find(key);
137 if (field != fields_map->end()) {
138 field->second.add(value);
139 } else {
140 fields_map->insert({key, cppbor::Array().add(value)});
141 }
142 }
143
144 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)145 insert_unknown_tag(const keymaster_key_param_t& param, cppbor::Map* dest_map,
146 std::unordered_map<EatClaim, cppbor::Array>* fields_map) {
147 EatClaim private_eat_tag = static_cast<EatClaim>(convert_to_eat_claim(param.tag));
148 switch (keymaster_tag_get_type(param.tag)) {
149 case KM_ENUM:
150 dest_map->add(private_eat_tag, param.enumerated);
151 break;
152 case KM_ENUM_REP:
153 add_repeating_enum(private_eat_tag, param.enumerated, fields_map);
154 break;
155 case KM_UINT:
156 dest_map->add(private_eat_tag, param.integer);
157 break;
158 case KM_UINT_REP:
159 add_repeating_enum(private_eat_tag, param.integer, fields_map);
160 break;
161 case KM_ULONG:
162 dest_map->add(private_eat_tag, param.long_integer);
163 break;
164 case KM_ULONG_REP:
165 add_repeating_enum(private_eat_tag, param.long_integer, fields_map);
166 break;
167 case KM_DATE:
168 dest_map->add(private_eat_tag, param.date_time);
169 break;
170 case KM_BOOL:
171 dest_map->add(private_eat_tag, true);
172 break;
173 case KM_BIGNUM:
174 case KM_BYTES:
175 dest_map->add(private_eat_tag, blob_to_bstr(param.blob));
176 break;
177 default:
178 ASSERT_OR_RETURN_ERROR(false, KM_ERROR_INVALID_TAG);
179 }
180 return KM_ERROR_OK;
181 }
182
183 /**
184 * Convert an IMEI encoded as a string of numbers into the UEID format defined in
185 * https://tools.ietf.org/html/draft-ietf-rats-eat.
186 * The resulting format is a bstr encoded as follows:
187 * - Type byte: 0x03
188 * - IMEI (without check digit), encoded as byte string of length 14 with each byte as the digit's
189 * value. The IMEI value encoded SHALL NOT include Luhn checksum or SVN information.
190 */
imei_to_ueid(const keymaster_blob_t & imei_blob,cppbor::Bstr * out)191 keymaster_error_t imei_to_ueid(const keymaster_blob_t& imei_blob, cppbor::Bstr* out) {
192 ASSERT_OR_RETURN_ERROR(imei_blob.data_length == kImeiBlobLength, KM_ERROR_INVALID_TAG);
193
194 uint8_t ueid[kUeidLength];
195 ueid[0] = kImeiTypeByte;
196 // imei_blob corresponds to android.telephony.TelephonyManager#getDeviceId(), which is the
197 // 15-digit IMEI (including the check digit), encoded as a string.
198 for (size_t i = 1; i < kUeidLength; i++) {
199 // Convert each character to its numeric value.
200 ueid[i] = imei_blob.data[i - 1] - '0'; // Intentionally skip check digit at last position.
201 }
202
203 *out = cppbor::Bstr(std::pair(ueid, sizeof(ueid)));
204 return KM_ERROR_OK;
205 }
206
ueid_to_imei_blob(const cppbor::Bstr * ueid,keymaster_blob_t * out)207 keymaster_error_t ueid_to_imei_blob(const cppbor::Bstr* ueid, keymaster_blob_t* out) {
208 ASSERT_OR_RETURN_ERROR(ueid, KM_ERROR_INVALID_TAG);
209 const std::vector<uint8_t>& ueid_vec = ueid->value();
210 ASSERT_OR_RETURN_ERROR(ueid_vec.size() == kUeidLength, KM_ERROR_INVALID_TAG);
211 ASSERT_OR_RETURN_ERROR(ueid_vec[0] == kImeiTypeByte, KM_ERROR_INVALID_TAG);
212
213 uint8_t* imei_string = (uint8_t*)calloc(kImeiBlobLength, sizeof(uint8_t));
214 // Fill string from left to right, and calculate Luhn check digit.
215 int luhn_digit_sum = 0;
216 for (size_t i = 0; i < kImeiBlobLength - 1; i++) {
217 uint8_t digit_i = ueid_vec[i + 1];
218 // Convert digit to its string value.
219 imei_string[i] = '0' + digit_i;
220 luhn_digit_sum += i % 2 == 0 ? digit_i : digit_i * 2 / 10 + (digit_i * 2) % 10;
221 }
222 imei_string[kImeiBlobLength - 1] = '0' + (10 - luhn_digit_sum % 10) % 10;
223
224 *out = {.data = imei_string, .data_length = kImeiBlobLength};
225 return KM_ERROR_OK;
226 }
227
ec_key_size_to_eat_curve(uint32_t key_size_bits,int * curve)228 keymaster_error_t ec_key_size_to_eat_curve(uint32_t key_size_bits, int* curve) {
229 switch (key_size_bits) {
230 default:
231 return KM_ERROR_UNSUPPORTED_KEY_SIZE;
232
233 case 224:
234 *curve = (int)EatEcCurve::P_224;
235 break;
236
237 case 256:
238 *curve = (int)EatEcCurve::P_256;
239 break;
240
241 case 384:
242 *curve = (int)EatEcCurve::P_384;
243 break;
244
245 case 521:
246 *curve = (int)EatEcCurve::P_521;
247 break;
248 }
249
250 return KM_ERROR_OK;
251 }
252
is_valid_attestation_challenge(const keymaster_blob_t & attestation_challenge)253 bool is_valid_attestation_challenge(const keymaster_blob_t& attestation_challenge) {
254 // TODO(171864369): Limit apps targeting >= API 30 to attestations in the range of
255 // [0, 128] bytes.
256 return (attestation_challenge.data_length <= kMaximumAttestationChallengeLength);
257 }
258
259 // 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)260 keymaster_error_t build_eat_submod(const AuthorizationSet& auth_list,
261 const EatSecurityLevel security_level, cppbor::Map* submod) {
262 ASSERT_OR_RETURN_ERROR(submod, KM_ERROR_UNEXPECTED_NULL_POINTER);
263
264 if (auth_list.empty()) return KM_ERROR_OK;
265
266 submod->add(EatClaim::SECURITY_LEVEL, get_uint32_value(security_level));
267
268 // Keep repeating fields in a separate map for easy lookup.
269 // Add them to submod map in postprocessing.
270 std::unordered_map<EatClaim, cppbor::Array> repeating_fields =
271 std::unordered_map<EatClaim, cppbor::Array>();
272
273 for (auto entry : auth_list) {
274
275 switch (entry.tag) {
276
277 default:
278 // Unknown tags should only be included if they're software-enforced.
279 if (security_level == EatSecurityLevel::UNRESTRICTED) {
280 keymaster_error_t error = insert_unknown_tag(entry, submod, &repeating_fields);
281 if (error != KM_ERROR_OK) {
282 return error;
283 }
284 }
285 break;
286
287 /* Tags ignored because they should never exist */
288 case KM_TAG_INVALID:
289
290 /* Tags ignored because they're not used. */
291 case KM_TAG_ALL_USERS:
292 case KM_TAG_EXPORTABLE:
293 case KM_TAG_ECIES_SINGLE_HASH_MODE:
294 case KM_TAG_KDF:
295
296 /* Tags ignored because they're used only to provide information to operations */
297 case KM_TAG_ASSOCIATED_DATA:
298 case KM_TAG_NONCE:
299 case KM_TAG_AUTH_TOKEN:
300 case KM_TAG_MAC_LENGTH:
301 case KM_TAG_ATTESTATION_CHALLENGE:
302 case KM_TAG_RESET_SINCE_ID_ROTATION:
303
304 /* Tags ignored because they have no meaning off-device */
305 case KM_TAG_USER_ID:
306 case KM_TAG_USER_SECURE_ID:
307 case KM_TAG_BLOB_USAGE_REQUIREMENTS:
308
309 /* Tags ignored because they're not usable by app keys */
310 case KM_TAG_BOOTLOADER_ONLY:
311 case KM_TAG_INCLUDE_UNIQUE_ID:
312 case KM_TAG_MAX_USES_PER_BOOT:
313 case KM_TAG_MIN_SECONDS_BETWEEN_OPS:
314 case KM_TAG_UNIQUE_ID:
315
316 /* Tags ignored because they contain data that should not be exported */
317 case KM_TAG_APPLICATION_DATA:
318 case KM_TAG_APPLICATION_ID:
319 case KM_TAG_ROOT_OF_TRUST:
320 continue;
321
322 /* Non-repeating enumerations */
323 case KM_TAG_ALGORITHM:
324 submod->add(EatClaim::ALGORITHM, get_uint32_value(entry));
325 break;
326 case KM_TAG_EC_CURVE:
327 submod->add(EatClaim::EC_CURVE, get_uint32_value(entry));
328 break;
329 case KM_TAG_USER_AUTH_TYPE:
330 submod->add(EatClaim::USER_AUTH_TYPE, get_uint32_value(entry));
331 break;
332 case KM_TAG_ORIGIN:
333 submod->add(EatClaim::ORIGIN, get_uint32_value(entry));
334 break;
335
336 /* Repeating enumerations */
337 case KM_TAG_PURPOSE:
338 add_repeating_enum(EatClaim::PURPOSE, get_uint32_value(entry), &repeating_fields);
339 break;
340 case KM_TAG_PADDING:
341 add_repeating_enum(EatClaim::PADDING, get_uint32_value(entry), &repeating_fields);
342 break;
343 case KM_TAG_DIGEST:
344 add_repeating_enum(EatClaim::DIGEST, get_uint32_value(entry), &repeating_fields);
345 break;
346 case KM_TAG_BLOCK_MODE:
347 add_repeating_enum(EatClaim::BLOCK_MODE, get_uint32_value(entry), &repeating_fields);
348 break;
349
350 /* Non-repeating unsigned integers */
351 case KM_TAG_KEY_SIZE:
352 submod->add(EatClaim::KEY_SIZE, get_uint32_value(entry));
353 break;
354 case KM_TAG_AUTH_TIMEOUT:
355 submod->add(EatClaim::AUTH_TIMEOUT, get_uint32_value(entry));
356 break;
357 case KM_TAG_OS_VERSION:
358 submod->add(EatClaim::OS_VERSION, get_uint32_value(entry));
359 break;
360 case KM_TAG_OS_PATCHLEVEL:
361 submod->add(EatClaim::OS_PATCHLEVEL, get_uint32_value(entry));
362 break;
363 case KM_TAG_VENDOR_PATCHLEVEL:
364 submod->add(EatClaim::VENDOR_PATCHLEVEL, get_uint32_value(entry));
365 break;
366 case KM_TAG_BOOT_PATCHLEVEL:
367 submod->add(EatClaim::BOOT_PATCHLEVEL, get_uint32_value(entry));
368 break;
369 case KM_TAG_MIN_MAC_LENGTH:
370 submod->add(EatClaim::MIN_MAC_LENGTH, get_uint32_value(entry));
371 break;
372
373 /* Non-repeating long unsigned integers */
374 case KM_TAG_RSA_PUBLIC_EXPONENT:
375 submod->add(EatClaim::RSA_PUBLIC_EXPONENT, entry.long_integer);
376 break;
377
378 /* Dates */
379 case KM_TAG_ACTIVE_DATETIME:
380 submod->add(EatClaim::ACTIVE_DATETIME, entry.date_time);
381 break;
382 case KM_TAG_ORIGINATION_EXPIRE_DATETIME:
383 submod->add(EatClaim::ORIGINATION_EXPIRE_DATETIME, entry.date_time);
384 break;
385 case KM_TAG_USAGE_EXPIRE_DATETIME:
386 submod->add(EatClaim::USAGE_EXPIRE_DATETIME, entry.date_time);
387 break;
388 case KM_TAG_CREATION_DATETIME:
389 submod->add(EatClaim::IAT, entry.date_time);
390 break;
391
392 /* Booleans */
393 case KM_TAG_NO_AUTH_REQUIRED:
394 submod->add(EatClaim::NO_AUTH_REQUIRED, true);
395 break;
396 case KM_TAG_ALL_APPLICATIONS:
397 submod->add(EatClaim::ALL_APPLICATIONS, true);
398 break;
399 case KM_TAG_ROLLBACK_RESISTANT:
400 submod->add(EatClaim::ROLLBACK_RESISTANT, true);
401 break;
402 case KM_TAG_ALLOW_WHILE_ON_BODY:
403 submod->add(EatClaim::ALLOW_WHILE_ON_BODY, true);
404 break;
405 case KM_TAG_UNLOCKED_DEVICE_REQUIRED:
406 submod->add(EatClaim::UNLOCKED_DEVICE_REQUIRED, true);
407 break;
408 case KM_TAG_CALLER_NONCE:
409 submod->add(EatClaim::CALLER_NONCE, true);
410 break;
411 case KM_TAG_TRUSTED_CONFIRMATION_REQUIRED:
412 submod->add(EatClaim::TRUSTED_CONFIRMATION_REQUIRED, true);
413 break;
414 case KM_TAG_EARLY_BOOT_ONLY:
415 submod->add(EatClaim::EARLY_BOOT_ONLY, true);
416 break;
417 case KM_TAG_DEVICE_UNIQUE_ATTESTATION:
418 submod->add(EatClaim::DEVICE_UNIQUE_ATTESTATION, true);
419 break;
420 case KM_TAG_IDENTITY_CREDENTIAL_KEY:
421 submod->add(EatClaim::IDENTITY_CREDENTIAL_KEY, true);
422 break;
423 case KM_TAG_TRUSTED_USER_PRESENCE_REQUIRED:
424 submod->add(EatClaim::TRUSTED_USER_PRESENCE_REQUIRED, true);
425 break;
426 case KM_TAG_STORAGE_KEY:
427 submod->add(EatClaim::STORAGE_KEY, true);
428 break;
429
430 /* Byte arrays*/
431 case KM_TAG_ATTESTATION_APPLICATION_ID:
432 submod->add(EatClaim::ATTESTATION_APPLICATION_ID, blob_to_bstr(entry.blob));
433 break;
434 case KM_TAG_ATTESTATION_ID_BRAND:
435 submod->add(EatClaim::ATTESTATION_ID_BRAND, blob_to_bstr(entry.blob));
436 break;
437 case KM_TAG_ATTESTATION_ID_DEVICE:
438 submod->add(EatClaim::ATTESTATION_ID_DEVICE, blob_to_bstr(entry.blob));
439 break;
440 case KM_TAG_ATTESTATION_ID_PRODUCT:
441 submod->add(EatClaim::ATTESTATION_ID_PRODUCT, blob_to_bstr(entry.blob));
442 break;
443 case KM_TAG_ATTESTATION_ID_SERIAL:
444 submod->add(EatClaim::ATTESTATION_ID_SERIAL, blob_to_bstr(entry.blob));
445 break;
446 case KM_TAG_ATTESTATION_ID_IMEI: {
447 cppbor::Bstr ueid("");
448 keymaster_error_t error = imei_to_ueid(entry.blob, &ueid);
449 if (error != KM_ERROR_OK) return error;
450 submod->add(EatClaim::UEID, ueid);
451 break;
452 }
453 case KM_TAG_ATTESTATION_ID_MEID:
454 submod->add(EatClaim::ATTESTATION_ID_MEID, blob_to_bstr(entry.blob));
455 break;
456 case KM_TAG_ATTESTATION_ID_MANUFACTURER:
457 submod->add(EatClaim::ATTESTATION_ID_MANUFACTURER, blob_to_bstr(entry.blob));
458 break;
459 case KM_TAG_ATTESTATION_ID_MODEL:
460 submod->add(EatClaim::ATTESTATION_ID_MODEL, blob_to_bstr(entry.blob));
461 break;
462 case KM_TAG_CONFIRMATION_TOKEN:
463 submod->add(EatClaim::CONFIRMATION_TOKEN, blob_to_bstr(entry.blob));
464 break;
465 }
466 }
467
468 // Move values from repeating enums into the submod map.
469 for (auto const& repeating_field : repeating_fields) {
470 EatClaim key = static_cast<EatClaim>(repeating_field.first);
471 submod->add(key, std::move(repeating_fields.at(key)));
472 }
473
474 int ec_curve;
475 uint32_t key_size;
476 if (auth_list.Contains(TAG_ALGORITHM, KM_ALGORITHM_EC) && !auth_list.Contains(TAG_EC_CURVE) &&
477 auth_list.GetTagValue(TAG_KEY_SIZE, &key_size)) {
478 // This must be a keymaster1 key. It's an EC key with no curve. Insert the curve.
479
480 keymaster_error_t error = ec_key_size_to_eat_curve(key_size, &ec_curve);
481 if (error != KM_ERROR_OK) return error;
482
483 submod->add(EatClaim::EC_CURVE, ec_curve);
484 }
485
486 return KM_ERROR_OK;
487 }
488
489 // Put the contents of the keymaster AuthorizationSet auth_list into the ASN.1 record structure,
490 // record.
build_auth_list(const AuthorizationSet & auth_list,KM_AUTH_LIST * record)491 keymaster_error_t build_auth_list(const AuthorizationSet& auth_list, KM_AUTH_LIST* record) {
492 ASSERT_OR_RETURN_ERROR(record, KM_ERROR_UNEXPECTED_NULL_POINTER);
493
494 if (auth_list.empty()) return KM_ERROR_OK;
495
496 for (auto entry : auth_list) {
497
498 ASN1_INTEGER_SET** integer_set = nullptr;
499 ASN1_INTEGER** integer_ptr = nullptr;
500 ASN1_OCTET_STRING** string_ptr = nullptr;
501 ASN1_NULL** bool_ptr = nullptr;
502
503 switch (entry.tag) {
504
505 /* Tags ignored because they should never exist */
506 case KM_TAG_INVALID:
507
508 /* Tags ignored because they're not used. */
509 case KM_TAG_ALL_USERS:
510 case KM_TAG_EXPORTABLE:
511 case KM_TAG_ECIES_SINGLE_HASH_MODE:
512
513 /* Tags ignored because they're used only to provide information to operations */
514 case KM_TAG_ASSOCIATED_DATA:
515 case KM_TAG_NONCE:
516 case KM_TAG_AUTH_TOKEN:
517 case KM_TAG_MAC_LENGTH:
518 case KM_TAG_ATTESTATION_CHALLENGE:
519 case KM_TAG_KDF:
520
521 /* Tags ignored because they're used only to provide for certificate generation */
522 case KM_TAG_CERTIFICATE_SERIAL:
523 case KM_TAG_CERTIFICATE_SUBJECT:
524 case KM_TAG_CERTIFICATE_NOT_BEFORE:
525 case KM_TAG_CERTIFICATE_NOT_AFTER:
526 case KM_TAG_INCLUDE_UNIQUE_ID:
527 case KM_TAG_RESET_SINCE_ID_ROTATION:
528
529 /* Tags ignored because they have no meaning off-device */
530 case KM_TAG_USER_ID:
531 case KM_TAG_USER_SECURE_ID:
532 case KM_TAG_BLOB_USAGE_REQUIREMENTS:
533
534 /* Tags ignored because they're not usable by app keys */
535 case KM_TAG_BOOTLOADER_ONLY:
536 case KM_TAG_MAX_BOOT_LEVEL:
537 case KM_TAG_MAX_USES_PER_BOOT:
538 case KM_TAG_MIN_SECONDS_BETWEEN_OPS:
539 case KM_TAG_STORAGE_KEY:
540 case KM_TAG_UNIQUE_ID:
541
542 /* Tags ignored because they contain data that should not be exported */
543 case KM_TAG_APPLICATION_DATA:
544 case KM_TAG_APPLICATION_ID:
545 case KM_TAG_CONFIRMATION_TOKEN:
546 case KM_TAG_ROOT_OF_TRUST:
547 continue;
548
549 /* Non-repeating enumerations */
550 case KM_TAG_ALGORITHM:
551 integer_ptr = &record->algorithm;
552 break;
553 case KM_TAG_EC_CURVE:
554 integer_ptr = &record->ec_curve;
555 break;
556 case KM_TAG_USER_AUTH_TYPE:
557 integer_ptr = &record->user_auth_type;
558 break;
559 case KM_TAG_ORIGIN:
560 integer_ptr = &record->origin;
561 break;
562
563 /* Repeating enumerations */
564 case KM_TAG_PURPOSE:
565 integer_set = &record->purpose;
566 break;
567 case KM_TAG_PADDING:
568 integer_set = &record->padding;
569 break;
570 case KM_TAG_DIGEST:
571 integer_set = &record->digest;
572 break;
573 case KM_TAG_BLOCK_MODE:
574 integer_set = &record->block_mode;
575 break;
576 case KM_TAG_RSA_OAEP_MGF_DIGEST:
577 integer_set = &record->mgf_digest;
578 break;
579
580 /* Non-repeating unsigned integers */
581 case KM_TAG_KEY_SIZE:
582 integer_ptr = &record->key_size;
583 break;
584 case KM_TAG_AUTH_TIMEOUT:
585 integer_ptr = &record->auth_timeout;
586 break;
587 case KM_TAG_OS_VERSION:
588 integer_ptr = &record->os_version;
589 break;
590 case KM_TAG_OS_PATCHLEVEL:
591 integer_ptr = &record->os_patchlevel;
592 break;
593 case KM_TAG_MIN_MAC_LENGTH:
594 integer_ptr = &record->min_mac_length;
595 break;
596 case KM_TAG_BOOT_PATCHLEVEL:
597 integer_ptr = &record->boot_patch_level;
598 break;
599 case KM_TAG_VENDOR_PATCHLEVEL:
600 integer_ptr = &record->vendor_patchlevel;
601 break;
602 case KM_TAG_USAGE_COUNT_LIMIT:
603 integer_ptr = &record->usage_count_limit;
604 break;
605
606 /* Non-repeating long unsigned integers */
607 case KM_TAG_RSA_PUBLIC_EXPONENT:
608 integer_ptr = &record->rsa_public_exponent;
609 break;
610
611 /* Dates */
612 case KM_TAG_ACTIVE_DATETIME:
613 integer_ptr = &record->active_date_time;
614 break;
615 case KM_TAG_ORIGINATION_EXPIRE_DATETIME:
616 integer_ptr = &record->origination_expire_date_time;
617 break;
618 case KM_TAG_USAGE_EXPIRE_DATETIME:
619 integer_ptr = &record->usage_expire_date_time;
620 break;
621 case KM_TAG_CREATION_DATETIME:
622 integer_ptr = &record->creation_date_time;
623 break;
624
625 /* Booleans */
626 case KM_TAG_NO_AUTH_REQUIRED:
627 bool_ptr = &record->no_auth_required;
628 break;
629 case KM_TAG_ALL_APPLICATIONS:
630 bool_ptr = &record->all_applications;
631 break;
632 case KM_TAG_ROLLBACK_RESISTANT:
633 bool_ptr = &record->rollback_resistant;
634 break;
635 case KM_TAG_ROLLBACK_RESISTANCE:
636 bool_ptr = &record->rollback_resistance;
637 break;
638 case KM_TAG_ALLOW_WHILE_ON_BODY:
639 bool_ptr = &record->allow_while_on_body;
640 break;
641 case KM_TAG_UNLOCKED_DEVICE_REQUIRED:
642 bool_ptr = &record->unlocked_device_required;
643 break;
644 case KM_TAG_CALLER_NONCE:
645 bool_ptr = &record->caller_nonce;
646 break;
647 case KM_TAG_TRUSTED_CONFIRMATION_REQUIRED:
648 bool_ptr = &record->trusted_confirmation_required;
649 break;
650 case KM_TAG_EARLY_BOOT_ONLY:
651 bool_ptr = &record->early_boot_only;
652 break;
653 case KM_TAG_DEVICE_UNIQUE_ATTESTATION:
654 bool_ptr = &record->device_unique_attestation;
655 break;
656 case KM_TAG_IDENTITY_CREDENTIAL_KEY:
657 bool_ptr = &record->identity_credential_key;
658 break;
659 case KM_TAG_TRUSTED_USER_PRESENCE_REQUIRED:
660 bool_ptr = &record->trusted_user_presence_required;
661 break;
662
663 /* Byte arrays*/
664 case KM_TAG_ATTESTATION_APPLICATION_ID:
665 string_ptr = &record->attestation_application_id;
666 break;
667 case KM_TAG_ATTESTATION_ID_BRAND:
668 string_ptr = &record->attestation_id_brand;
669 break;
670 case KM_TAG_ATTESTATION_ID_DEVICE:
671 string_ptr = &record->attestation_id_device;
672 break;
673 case KM_TAG_ATTESTATION_ID_PRODUCT:
674 string_ptr = &record->attestation_id_product;
675 break;
676 case KM_TAG_ATTESTATION_ID_SERIAL:
677 string_ptr = &record->attestation_id_serial;
678 break;
679 case KM_TAG_ATTESTATION_ID_IMEI:
680 string_ptr = &record->attestation_id_imei;
681 break;
682 case KM_TAG_ATTESTATION_ID_MEID:
683 string_ptr = &record->attestation_id_meid;
684 break;
685 case KM_TAG_ATTESTATION_ID_MANUFACTURER:
686 string_ptr = &record->attestation_id_manufacturer;
687 break;
688 case KM_TAG_ATTESTATION_ID_MODEL:
689 string_ptr = &record->attestation_id_model;
690 break;
691 }
692
693 keymaster_tag_type_t type = keymaster_tag_get_type(entry.tag);
694 switch (type) {
695 case KM_ENUM:
696 case KM_ENUM_REP:
697 case KM_UINT:
698 case KM_UINT_REP: {
699 ASSERT_OR_RETURN_ERROR((keymaster_tag_repeatable(entry.tag) && integer_set) ||
700 (!keymaster_tag_repeatable(entry.tag) && integer_ptr),
701 KM_ERROR_INVALID_TAG);
702
703 UniquePtr<ASN1_INTEGER, ASN1_INTEGER_Delete> value(ASN1_INTEGER_new());
704 if (!value.get()) {
705 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
706 }
707 if (!ASN1_INTEGER_set(value.get(), get_uint32_value(entry))) {
708 return TranslateLastOpenSslError();
709 }
710
711 insert_integer(value.release(), integer_ptr, integer_set);
712 break;
713 }
714
715 case KM_ULONG:
716 case KM_ULONG_REP:
717 case KM_DATE: {
718 ASSERT_OR_RETURN_ERROR((keymaster_tag_repeatable(entry.tag) && integer_set) ||
719 (!keymaster_tag_repeatable(entry.tag) && integer_ptr),
720 KM_ERROR_INVALID_TAG);
721
722 UniquePtr<BIGNUM, BIGNUM_Delete> bn_value(BN_new());
723 if (!bn_value.get()) {
724 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
725 }
726
727 if (type == KM_DATE) {
728 if (!BN_set_u64(bn_value.get(), entry.date_time)) {
729 return TranslateLastOpenSslError();
730 }
731 } else {
732 if (!BN_set_u64(bn_value.get(), entry.long_integer)) {
733 return TranslateLastOpenSslError();
734 }
735 }
736
737 UniquePtr<ASN1_INTEGER, ASN1_INTEGER_Delete> value(
738 BN_to_ASN1_INTEGER(bn_value.get(), nullptr));
739 if (!value.get()) {
740 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
741 }
742
743 insert_integer(value.release(), integer_ptr, integer_set);
744 break;
745 }
746
747 case KM_BOOL:
748 ASSERT_OR_RETURN_ERROR(bool_ptr, KM_ERROR_INVALID_TAG);
749 if (!*bool_ptr) *bool_ptr = ASN1_NULL_new();
750 if (!*bool_ptr) return KM_ERROR_MEMORY_ALLOCATION_FAILED;
751 break;
752
753 /* Byte arrays*/
754 case KM_BYTES:
755 ASSERT_OR_RETURN_ERROR(string_ptr, KM_ERROR_INVALID_TAG);
756 if (!*string_ptr) {
757 *string_ptr = ASN1_OCTET_STRING_new();
758 }
759 if (!*string_ptr) {
760 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
761 }
762 if (!ASN1_OCTET_STRING_set(*string_ptr, entry.blob.data, entry.blob.data_length)) {
763 return TranslateLastOpenSslError();
764 }
765 break;
766
767 default:
768 return KM_ERROR_UNIMPLEMENTED;
769 }
770 }
771
772 keymaster_ec_curve_t ec_curve;
773 uint32_t key_size;
774 if (auth_list.Contains(TAG_ALGORITHM, KM_ALGORITHM_EC) && //
775 !auth_list.Contains(TAG_EC_CURVE) && //
776 auth_list.GetTagValue(TAG_KEY_SIZE, &key_size)) {
777 // This must be a keymaster1 key. It's an EC key with no curve. Insert the curve.
778
779 keymaster_error_t error = EcKeySizeToCurve(key_size, &ec_curve);
780 if (error != KM_ERROR_OK) return error;
781
782 UniquePtr<ASN1_INTEGER, ASN1_INTEGER_Delete> value(ASN1_INTEGER_new());
783 if (!value.get()) {
784 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
785 }
786
787 if (!ASN1_INTEGER_set(value.get(), ec_curve)) {
788 return TranslateLastOpenSslError();
789 }
790
791 insert_integer(value.release(), &record->ec_curve, nullptr);
792 }
793
794 return KM_ERROR_OK;
795 }
796
797 // Construct a CBOR-encoded attestation record containing the values from sw_enforced
798 // 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)799 keymaster_error_t build_eat_record(const AuthorizationSet& attestation_params,
800 AuthorizationSet sw_enforced, AuthorizationSet tee_enforced,
801 const AttestationContext& context,
802 std::vector<uint8_t>* eat_token) {
803 ASSERT_OR_RETURN_ERROR(eat_token, KM_ERROR_UNEXPECTED_NULL_POINTER);
804
805 cppbor::Map eat_record;
806 switch (context.GetSecurityLevel()) {
807 case KM_SECURITY_LEVEL_SOFTWARE:
808 eat_record.add(EatClaim::SECURITY_LEVEL, get_uint32_value(EatSecurityLevel::UNRESTRICTED));
809 break;
810 case KM_SECURITY_LEVEL_TRUSTED_ENVIRONMENT:
811 eat_record.add(EatClaim::SECURITY_LEVEL,
812 get_uint32_value(EatSecurityLevel::SECURE_RESTRICTED));
813 break;
814 case KM_SECURITY_LEVEL_STRONGBOX:
815 eat_record.add(EatClaim::SECURITY_LEVEL, get_uint32_value(EatSecurityLevel::HARDWARE));
816 break;
817 default:
818 return KM_ERROR_UNKNOWN_ERROR;
819 }
820
821 keymaster_error_t error;
822 const AttestationContext::VerifiedBootParams* vb_params = context.GetVerifiedBootParams(&error);
823 if (error != KM_ERROR_OK) return error;
824
825 if (vb_params->verified_boot_key.data_length) {
826 eat_record.add(EatClaim::VERIFIED_BOOT_KEY, blob_to_bstr(vb_params->verified_boot_key));
827 }
828 if (vb_params->verified_boot_hash.data_length) {
829 eat_record.add(EatClaim::VERIFIED_BOOT_HASH, blob_to_bstr(vb_params->verified_boot_hash));
830 }
831 if (vb_params->device_locked) {
832 eat_record.add(EatClaim::DEVICE_LOCKED, vb_params->device_locked);
833 }
834
835 bool verified_or_self_signed = (vb_params->verified_boot_state == KM_VERIFIED_BOOT_VERIFIED ||
836 vb_params->verified_boot_state == KM_VERIFIED_BOOT_SELF_SIGNED);
837 auto eat_boot_state = cppbor::Array()
838 .add(verified_or_self_signed) // secure-boot-enabled
839 .add(verified_or_self_signed) // debug-disabled
840 .add(verified_or_self_signed) // debug-disabled-since-boot
841 .add(verified_or_self_signed) // debug-permanent-disable
842 .add(false); // debug-full-permanent-disable (no way to verify)
843 eat_record.add(EatClaim::BOOT_STATE, std::move(eat_boot_state));
844 eat_record.add(EatClaim::OFFICIAL_BUILD,
845 vb_params->verified_boot_state == KM_VERIFIED_BOOT_VERIFIED);
846
847 eat_record.add(EatClaim::ATTESTATION_VERSION,
848 version_to_attestation_version(context.GetKmVersion()));
849 eat_record.add(EatClaim::KEYMASTER_VERSION,
850 version_to_attestation_km_version(context.GetKmVersion()));
851
852 keymaster_blob_t attestation_challenge = {nullptr, 0};
853 if (!attestation_params.GetTagValue(TAG_ATTESTATION_CHALLENGE, &attestation_challenge)) {
854 return KM_ERROR_ATTESTATION_CHALLENGE_MISSING;
855 }
856
857 if (!is_valid_attestation_challenge(attestation_challenge)) {
858 return KM_ERROR_INVALID_INPUT_LENGTH;
859 }
860
861 eat_record.add(EatClaim::NONCE, blob_to_bstr(attestation_challenge));
862
863 keymaster_blob_t attestation_app_id;
864 if (!attestation_params.GetTagValue(TAG_ATTESTATION_APPLICATION_ID, &attestation_app_id)) {
865 return KM_ERROR_ATTESTATION_APPLICATION_ID_MISSING;
866 }
867 // TODO: what should happen when sw_enforced already contains TAG_ATTESTATION_APPLICATION_ID?
868 // (as is the case in android_keymaster_test.cpp). For now, we will ignore the provided one in
869 // attestation_params if that's the case.
870 keymaster_blob_t existing_app_id;
871 if (!sw_enforced.GetTagValue(TAG_ATTESTATION_APPLICATION_ID, &existing_app_id)) {
872 sw_enforced.push_back(TAG_ATTESTATION_APPLICATION_ID, attestation_app_id);
873 }
874
875 error = context.VerifyAndCopyDeviceIds(
876 attestation_params,
877 context.GetSecurityLevel() == KM_SECURITY_LEVEL_SOFTWARE ? &sw_enforced : &tee_enforced);
878 if (error == KM_ERROR_UNIMPLEMENTED) {
879 // The KeymasterContext implementation does not support device ID attestation. Bail out if
880 // device ID attestation is being attempted.
881 for (const auto& tag : kDeviceAttestationTags) {
882 if (attestation_params.find(tag) != -1) {
883 return KM_ERROR_CANNOT_ATTEST_IDS;
884 }
885 }
886 } else if (error != KM_ERROR_OK) {
887 return error;
888 }
889
890 if (attestation_params.Contains(TAG_DEVICE_UNIQUE_ATTESTATION) &&
891 context.GetSecurityLevel() == KM_SECURITY_LEVEL_STRONGBOX) {
892 eat_record.add(EatClaim::DEVICE_UNIQUE_ATTESTATION, true);
893 }
894
895 cppbor::Map software_submod;
896 error = build_eat_submod(sw_enforced, EatSecurityLevel::UNRESTRICTED, &software_submod);
897 if (error != KM_ERROR_OK) return error;
898
899 cppbor::Map tee_submod;
900 error = build_eat_submod(tee_enforced, EatSecurityLevel::SECURE_RESTRICTED, &tee_submod);
901 if (error != KM_ERROR_OK) return error;
902
903 if (software_submod.size() + tee_submod.size() > 0) {
904 cppbor::Map submods;
905 if (software_submod.size() > 0) {
906 submods.add(kEatSubmodNameSoftware, std::move(software_submod));
907 }
908 if (tee_submod.size() > 0) {
909 submods.add(kEatSubmodNameTee, std::move(tee_submod));
910 }
911
912 eat_record.add(EatClaim::SUBMODS, std::move(submods));
913 }
914
915 if (attestation_params.GetTagValue(TAG_INCLUDE_UNIQUE_ID)) {
916 uint64_t creation_datetime;
917 // Only check sw_enforced for TAG_CREATION_DATETIME, since it shouldn't be in tee_enforced,
918 // since this implementation has no secure wall clock.
919 if (!sw_enforced.GetTagValue(TAG_CREATION_DATETIME, &creation_datetime)) {
920 LOG_E("Unique ID cannot be created without creation datetime", 0);
921 return KM_ERROR_INVALID_KEY_BLOB;
922 }
923
924 Buffer unique_id = context.GenerateUniqueId(
925 creation_datetime, attestation_app_id,
926 attestation_params.GetTagValue(TAG_RESET_SINCE_ID_ROTATION), &error);
927 if (error != KM_ERROR_OK) return error;
928
929 eat_record.add(EatClaim::CTI,
930 cppbor::Bstr(std::pair(unique_id.begin(), unique_id.available_read())));
931 }
932
933 *eat_token = eat_record.encode();
934
935 return KM_ERROR_OK;
936 }
937
build_unique_id_input(uint64_t creation_date_time,const keymaster_blob_t & application_id,bool reset_since_rotation)938 std::vector<uint8_t> build_unique_id_input(uint64_t creation_date_time,
939 const keymaster_blob_t& application_id,
940 bool reset_since_rotation) {
941 uint64_t rounded_date = creation_date_time / 2592000000LLU;
942 uint8_t* serialized_date = reinterpret_cast<uint8_t*>(&rounded_date);
943
944 std::vector<uint8_t> input;
945 input.insert(input.end(), serialized_date, serialized_date + sizeof(rounded_date));
946 input.insert(input.end(), application_id.data,
947 application_id.data + application_id.data_length);
948 input.push_back(reset_since_rotation ? 1 : 0);
949 return input;
950 }
951
generate_unique_id(const std::vector<uint8_t> & hbk,uint64_t creation_date_time,const keymaster_blob_t & application_id,bool reset_since_rotation)952 Buffer generate_unique_id(const std::vector<uint8_t>& hbk, uint64_t creation_date_time,
953 const keymaster_blob_t& application_id, bool reset_since_rotation) {
954 HmacSha256 hmac;
955 hmac.Init(hbk.data(), hbk.size());
956
957 std::vector<uint8_t> input =
958 build_unique_id_input(creation_date_time, application_id, reset_since_rotation);
959 Buffer unique_id(UNIQUE_ID_SIZE);
960 hmac.Sign(input.data(), input.size(), unique_id.peek_write(), unique_id.available_write());
961 unique_id.advance_write(UNIQUE_ID_SIZE);
962 return unique_id;
963 }
964
965 // Construct an ASN1.1 DER-encoded attestation record containing the values from sw_enforced and
966 // 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)967 keymaster_error_t build_attestation_record(const AuthorizationSet& attestation_params, //
968 AuthorizationSet sw_enforced,
969 AuthorizationSet tee_enforced,
970 const AttestationContext& context,
971 UniquePtr<uint8_t[]>* asn1_key_desc,
972 size_t* asn1_key_desc_len) {
973 ASSERT_OR_RETURN_ERROR(asn1_key_desc && asn1_key_desc_len, KM_ERROR_UNEXPECTED_NULL_POINTER);
974
975 UniquePtr<KM_KEY_DESCRIPTION, KM_KEY_DESCRIPTION_Delete> key_desc(KM_KEY_DESCRIPTION_new());
976 if (!key_desc.get()) return KM_ERROR_MEMORY_ALLOCATION_FAILED;
977
978 KM_ROOT_OF_TRUST* root_of_trust = nullptr;
979 if (context.GetSecurityLevel() == KM_SECURITY_LEVEL_SOFTWARE) {
980 key_desc->software_enforced->root_of_trust = KM_ROOT_OF_TRUST_new();
981 root_of_trust = key_desc->software_enforced->root_of_trust;
982 } else {
983 key_desc->tee_enforced->root_of_trust = KM_ROOT_OF_TRUST_new();
984 root_of_trust = key_desc->tee_enforced->root_of_trust;
985 }
986
987 keymaster_error_t error;
988 auto vb_params = context.GetVerifiedBootParams(&error);
989 if (error != KM_ERROR_OK) return error;
990 if (vb_params->verified_boot_key.data_length &&
991 !ASN1_OCTET_STRING_set(root_of_trust->verified_boot_key, vb_params->verified_boot_key.data,
992 vb_params->verified_boot_key.data_length)) {
993 return TranslateLastOpenSslError();
994 }
995 if (vb_params->verified_boot_hash.data_length &&
996 !ASN1_OCTET_STRING_set(root_of_trust->verified_boot_hash,
997 vb_params->verified_boot_hash.data,
998 vb_params->verified_boot_hash.data_length)) {
999 return TranslateLastOpenSslError();
1000 }
1001
1002 root_of_trust->device_locked = vb_params->device_locked ? 0xFF : 0x00;
1003 if (!ASN1_ENUMERATED_set(root_of_trust->verified_boot_state, vb_params->verified_boot_state)) {
1004 return TranslateLastOpenSslError();
1005 }
1006
1007 if (!ASN1_INTEGER_set(key_desc->attestation_version,
1008 version_to_attestation_version(context.GetKmVersion())) ||
1009 !ASN1_ENUMERATED_set(key_desc->attestation_security_level, context.GetSecurityLevel()) ||
1010 !ASN1_INTEGER_set(key_desc->keymaster_version,
1011 version_to_attestation_km_version(context.GetKmVersion())) ||
1012 !ASN1_ENUMERATED_set(key_desc->keymaster_security_level, context.GetSecurityLevel())) {
1013 return TranslateLastOpenSslError();
1014 }
1015
1016 keymaster_blob_t attestation_challenge = {nullptr, 0};
1017 if (!attestation_params.GetTagValue(TAG_ATTESTATION_CHALLENGE, &attestation_challenge)) {
1018 return KM_ERROR_ATTESTATION_CHALLENGE_MISSING;
1019 }
1020
1021 if (!is_valid_attestation_challenge(attestation_challenge)) {
1022 return KM_ERROR_INVALID_INPUT_LENGTH;
1023 }
1024
1025 if (!ASN1_OCTET_STRING_set(key_desc->attestation_challenge, attestation_challenge.data,
1026 attestation_challenge.data_length)) {
1027 return TranslateLastOpenSslError();
1028 }
1029
1030 keymaster_blob_t attestation_app_id;
1031 if (!attestation_params.GetTagValue(TAG_ATTESTATION_APPLICATION_ID, &attestation_app_id)) {
1032 return KM_ERROR_ATTESTATION_APPLICATION_ID_MISSING;
1033 }
1034 sw_enforced.push_back(TAG_ATTESTATION_APPLICATION_ID, attestation_app_id);
1035
1036 error = context.VerifyAndCopyDeviceIds(
1037 attestation_params,
1038 context.GetSecurityLevel() == KM_SECURITY_LEVEL_SOFTWARE ? &sw_enforced : &tee_enforced);
1039 if (error == KM_ERROR_UNIMPLEMENTED) {
1040 // The KeymasterContext implementation does not support device ID attestation. Bail out if
1041 // device ID attestation is being attempted.
1042 for (const auto& tag : kDeviceAttestationTags) {
1043 if (attestation_params.find(tag) != -1) {
1044 return KM_ERROR_CANNOT_ATTEST_IDS;
1045 }
1046 }
1047 } else if (error != KM_ERROR_OK) {
1048 return error;
1049 }
1050
1051 if (attestation_params.Contains(TAG_DEVICE_UNIQUE_ATTESTATION) &&
1052 context.GetSecurityLevel() == KM_SECURITY_LEVEL_STRONGBOX) {
1053 tee_enforced.push_back(TAG_DEVICE_UNIQUE_ATTESTATION);
1054 };
1055
1056 error = build_auth_list(sw_enforced, key_desc->software_enforced);
1057 if (error != KM_ERROR_OK) return error;
1058
1059 error = build_auth_list(tee_enforced, key_desc->tee_enforced);
1060 if (error != KM_ERROR_OK) return error;
1061
1062 if (attestation_params.GetTagValue(TAG_INCLUDE_UNIQUE_ID)) {
1063 uint64_t creation_datetime;
1064 // Only check sw_enforced for TAG_CREATION_DATETIME, since it shouldn't be in tee_enforced,
1065 // since this implementation has no secure wall clock.
1066 if (!sw_enforced.GetTagValue(TAG_CREATION_DATETIME, &creation_datetime)) {
1067 LOG_E("Unique ID cannot be created without creation datetime", 0);
1068 return KM_ERROR_INVALID_KEY_BLOB;
1069 }
1070
1071 Buffer unique_id = context.GenerateUniqueId(
1072 creation_datetime, attestation_app_id,
1073 attestation_params.GetTagValue(TAG_RESET_SINCE_ID_ROTATION), &error);
1074 if (error != KM_ERROR_OK) return error;
1075
1076 key_desc->unique_id = ASN1_OCTET_STRING_new();
1077 if (!key_desc->unique_id ||
1078 !ASN1_OCTET_STRING_set(key_desc->unique_id, unique_id.peek_read(),
1079 unique_id.available_read()))
1080 return TranslateLastOpenSslError();
1081 }
1082
1083 int len = i2d_KM_KEY_DESCRIPTION(key_desc.get(), nullptr);
1084 if (len < 0) return TranslateLastOpenSslError();
1085 *asn1_key_desc_len = len;
1086 asn1_key_desc->reset(new (std::nothrow) uint8_t[*asn1_key_desc_len]);
1087 if (!asn1_key_desc->get()) return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1088 uint8_t* p = asn1_key_desc->get();
1089 len = i2d_KM_KEY_DESCRIPTION(key_desc.get(), &p);
1090 if (len < 0) return TranslateLastOpenSslError();
1091
1092 return KM_ERROR_OK;
1093 }
1094
1095 // 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)1096 static bool get_repeated_enums(const ASN1_INTEGER_SET* stack, keymaster_tag_t tag,
1097 AuthorizationSet* auth_list) {
1098 ASSERT_OR_RETURN_ERROR(keymaster_tag_get_type(tag) == KM_ENUM_REP, KM_ERROR_INVALID_TAG);
1099 for (size_t i = 0; i < sk_ASN1_INTEGER_num(stack); ++i) {
1100 if (!auth_list->push_back(
1101 keymaster_param_enum(tag, ASN1_INTEGER_get(sk_ASN1_INTEGER_value(stack, i)))))
1102 return false;
1103 }
1104 return true;
1105 }
1106
1107 // Add the specified integer tag/value pair to auth_list.
1108 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)1109 static bool get_enum(const ASN1_INTEGER* asn1_int, TypedEnumTag<Type, Tag, KeymasterEnum> tag,
1110 AuthorizationSet* auth_list) {
1111 if (!asn1_int) return true;
1112 return auth_list->push_back(tag, static_cast<KeymasterEnum>(ASN1_INTEGER_get(asn1_int)));
1113 }
1114
1115 // Add the specified ulong tag/value pair to auth_list.
get_ulong(const ASN1_INTEGER * asn1_int,keymaster_tag_t tag,AuthorizationSet * auth_list)1116 static bool get_ulong(const ASN1_INTEGER* asn1_int, keymaster_tag_t tag,
1117 AuthorizationSet* auth_list) {
1118 if (!asn1_int) return true;
1119 UniquePtr<BIGNUM, BIGNUM_Delete> bn(ASN1_INTEGER_to_BN(asn1_int, nullptr));
1120 if (!bn.get()) return false;
1121 uint64_t ulong = 0;
1122 BN_get_u64(bn.get(), &ulong);
1123 return auth_list->push_back(keymaster_param_long(tag, ulong));
1124 }
1125
1126 // 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)1127 keymaster_error_t extract_auth_list(const KM_AUTH_LIST* record, AuthorizationSet* auth_list) {
1128 if (!record) return KM_ERROR_OK;
1129
1130 // Purpose
1131 if (!get_repeated_enums(record->purpose, TAG_PURPOSE, auth_list)) {
1132 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1133 }
1134
1135 // Algorithm
1136 if (!get_enum(record->algorithm, TAG_ALGORITHM, auth_list)) {
1137 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1138 }
1139
1140 // Key size
1141 if (record->key_size &&
1142 !auth_list->push_back(TAG_KEY_SIZE, ASN1_INTEGER_get(record->key_size))) {
1143 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1144 }
1145
1146 // Block mode
1147 if (!get_repeated_enums(record->block_mode, TAG_BLOCK_MODE, auth_list)) {
1148 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1149 }
1150
1151 // Digest
1152 if (!get_repeated_enums(record->digest, TAG_DIGEST, auth_list)) {
1153 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1154 }
1155
1156 // Padding
1157 if (!get_repeated_enums(record->padding, TAG_PADDING, auth_list)) {
1158 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1159 }
1160
1161 // Caller nonce
1162 if (record->caller_nonce && !auth_list->push_back(TAG_CALLER_NONCE)) {
1163 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1164 }
1165
1166 // Min mac length
1167 if (!get_ulong(record->min_mac_length, TAG_MIN_MAC_LENGTH, auth_list)) {
1168 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1169 }
1170
1171 // EC curve
1172 if (!get_enum(record->ec_curve, TAG_EC_CURVE, auth_list)) {
1173 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1174 }
1175
1176 // RSA public exponent
1177 if (!get_ulong(record->rsa_public_exponent, TAG_RSA_PUBLIC_EXPONENT, auth_list)) {
1178 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1179 }
1180
1181 // Rsa Oaep Mgf Digest
1182 if (!get_repeated_enums(record->mgf_digest, TAG_RSA_OAEP_MGF_DIGEST, auth_list)) {
1183 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1184 }
1185
1186 // Rollback resistance
1187 if (record->rollback_resistance && !auth_list->push_back(TAG_ROLLBACK_RESISTANCE)) {
1188 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1189 }
1190
1191 // Early boot only
1192 if (record->early_boot_only && !auth_list->push_back(TAG_EARLY_BOOT_ONLY)) {
1193 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1194 }
1195
1196 // Active date time
1197 if (!get_ulong(record->active_date_time, TAG_ACTIVE_DATETIME, auth_list)) {
1198 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1199 }
1200
1201 // Origination expire date time
1202 if (!get_ulong(record->origination_expire_date_time, TAG_ORIGINATION_EXPIRE_DATETIME,
1203 auth_list)) {
1204 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1205 }
1206
1207 // Usage Expire date time
1208 if (!get_ulong(record->usage_expire_date_time, TAG_USAGE_EXPIRE_DATETIME, auth_list)) {
1209 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1210 }
1211
1212 // Usage count limit
1213 if (record->usage_count_limit &&
1214 !auth_list->push_back(TAG_USAGE_COUNT_LIMIT, ASN1_INTEGER_get(record->usage_count_limit))) {
1215 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1216 }
1217
1218 // No auth required
1219 if (record->no_auth_required && !auth_list->push_back(TAG_NO_AUTH_REQUIRED)) {
1220 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1221 }
1222
1223 // User auth type
1224 if (!get_enum(record->user_auth_type, TAG_USER_AUTH_TYPE, auth_list)) {
1225 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1226 }
1227
1228 // Auth timeout
1229 if (record->auth_timeout &&
1230 !auth_list->push_back(TAG_AUTH_TIMEOUT, ASN1_INTEGER_get(record->auth_timeout))) {
1231 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1232 }
1233
1234 // Allow while on body
1235 if (record->allow_while_on_body && !auth_list->push_back(TAG_ALLOW_WHILE_ON_BODY)) {
1236 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1237 }
1238
1239 // trusted user presence required
1240 if (record->trusted_user_presence_required &&
1241 !auth_list->push_back(TAG_TRUSTED_USER_PRESENCE_REQUIRED)) {
1242 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1243 }
1244
1245 // trusted confirmation required
1246 if (record->trusted_confirmation_required &&
1247 !auth_list->push_back(TAG_TRUSTED_CONFIRMATION_REQUIRED)) {
1248 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1249 }
1250
1251 // Unlocked device required
1252 if (record->unlocked_device_required && !auth_list->push_back(TAG_UNLOCKED_DEVICE_REQUIRED)) {
1253 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1254 }
1255
1256 // All applications
1257 if (record->all_applications && !auth_list->push_back(TAG_ALL_APPLICATIONS)) {
1258 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1259 }
1260
1261 // Application ID
1262 if (record->application_id &&
1263 !auth_list->push_back(TAG_APPLICATION_ID, record->application_id->data,
1264 record->application_id->length)) {
1265 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1266 }
1267
1268 // Creation date time
1269 if (!get_ulong(record->creation_date_time, TAG_CREATION_DATETIME, auth_list)) {
1270 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1271 }
1272
1273 // Origin
1274 if (!get_enum(record->origin, TAG_ORIGIN, auth_list)) {
1275 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1276 }
1277
1278 // Rollback resistant
1279 if (record->rollback_resistant && !auth_list->push_back(TAG_ROLLBACK_RESISTANT)) {
1280 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1281 }
1282
1283 // Root of trust
1284 if (record->root_of_trust) {
1285 KM_ROOT_OF_TRUST* rot = record->root_of_trust;
1286 if (!rot->verified_boot_key) return KM_ERROR_INVALID_KEY_BLOB;
1287
1288 // Other root of trust fields are not mapped to auth set entries.
1289 }
1290
1291 // OS Version
1292 if (record->os_version &&
1293 !auth_list->push_back(TAG_OS_VERSION, ASN1_INTEGER_get(record->os_version))) {
1294 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1295 }
1296
1297 // OS Patch level
1298 if (record->os_patchlevel &&
1299 !auth_list->push_back(TAG_OS_PATCHLEVEL, ASN1_INTEGER_get(record->os_patchlevel))) {
1300 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1301 }
1302
1303 // attestation application Id
1304 if (record->attestation_application_id &&
1305 !auth_list->push_back(TAG_ATTESTATION_APPLICATION_ID,
1306 record->attestation_application_id->data,
1307 record->attestation_application_id->length)) {
1308 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1309 }
1310
1311 // Brand name
1312 if (record->attestation_id_brand &&
1313 !auth_list->push_back(TAG_ATTESTATION_ID_BRAND, record->attestation_id_brand->data,
1314 record->attestation_id_brand->length)) {
1315 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1316 }
1317
1318 // Device name
1319 if (record->attestation_id_device &&
1320 !auth_list->push_back(TAG_ATTESTATION_ID_DEVICE, record->attestation_id_device->data,
1321 record->attestation_id_device->length)) {
1322 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1323 }
1324
1325 // Product name
1326 if (record->attestation_id_product &&
1327 !auth_list->push_back(TAG_ATTESTATION_ID_PRODUCT, record->attestation_id_product->data,
1328 record->attestation_id_product->length)) {
1329 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1330 }
1331
1332 // Serial number
1333 if (record->attestation_id_serial &&
1334 !auth_list->push_back(TAG_ATTESTATION_ID_SERIAL, record->attestation_id_serial->data,
1335 record->attestation_id_serial->length)) {
1336 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1337 }
1338
1339 // IMEI
1340 if (record->attestation_id_imei &&
1341 !auth_list->push_back(TAG_ATTESTATION_ID_IMEI, record->attestation_id_imei->data,
1342 record->attestation_id_imei->length)) {
1343 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1344 }
1345
1346 // MEID
1347 if (record->attestation_id_meid &&
1348 !auth_list->push_back(TAG_ATTESTATION_ID_MEID, record->attestation_id_meid->data,
1349 record->attestation_id_meid->length)) {
1350 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1351 }
1352
1353 // Manufacturer name
1354 if (record->attestation_id_manufacturer &&
1355 !auth_list->push_back(TAG_ATTESTATION_ID_MANUFACTURER,
1356 record->attestation_id_manufacturer->data,
1357 record->attestation_id_manufacturer->length)) {
1358 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1359 }
1360
1361 // Model name
1362 if (record->attestation_id_model &&
1363 !auth_list->push_back(TAG_ATTESTATION_ID_MODEL, record->attestation_id_model->data,
1364 record->attestation_id_model->length)) {
1365 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1366 }
1367
1368 // vendor patch level
1369 if (record->vendor_patchlevel &&
1370 !auth_list->push_back(TAG_VENDOR_PATCHLEVEL, ASN1_INTEGER_get(record->vendor_patchlevel))) {
1371 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1372 }
1373
1374 // boot patch level
1375 if (record->boot_patch_level &&
1376 !auth_list->push_back(TAG_BOOT_PATCHLEVEL, ASN1_INTEGER_get(record->boot_patch_level))) {
1377 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1378 }
1379
1380 // device unique attestation
1381 if (record->device_unique_attestation && !auth_list->push_back(TAG_DEVICE_UNIQUE_ATTESTATION)) {
1382 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1383 }
1384
1385 // identity credential key
1386 if (record->identity_credential_key && !auth_list->push_back(TAG_IDENTITY_CREDENTIAL_KEY)) {
1387 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
1388 }
1389
1390 return KM_ERROR_OK;
1391 }
1392
1393 // Parse the DER-encoded attestation record, placing the results in keymaster_version,
1394 // 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)1395 keymaster_error_t parse_attestation_record(const uint8_t* asn1_key_desc, size_t asn1_key_desc_len,
1396 uint32_t* attestation_version, //
1397 keymaster_security_level_t* attestation_security_level,
1398 uint32_t* keymaster_version,
1399 keymaster_security_level_t* keymaster_security_level,
1400 keymaster_blob_t* attestation_challenge,
1401 AuthorizationSet* software_enforced,
1402 AuthorizationSet* tee_enforced,
1403 keymaster_blob_t* unique_id) {
1404 const uint8_t* p = asn1_key_desc;
1405 UniquePtr<KM_KEY_DESCRIPTION, KM_KEY_DESCRIPTION_Delete> record(
1406 d2i_KM_KEY_DESCRIPTION(nullptr, &p, asn1_key_desc_len));
1407 if (!record.get()) return TranslateLastOpenSslError();
1408
1409 *attestation_version = ASN1_INTEGER_get(record->attestation_version);
1410 *attestation_security_level = static_cast<keymaster_security_level_t>(
1411 ASN1_ENUMERATED_get(record->attestation_security_level));
1412 *keymaster_version = ASN1_INTEGER_get(record->keymaster_version);
1413 *keymaster_security_level = static_cast<keymaster_security_level_t>(
1414 ASN1_ENUMERATED_get(record->keymaster_security_level));
1415
1416 attestation_challenge->data =
1417 dup_buffer(record->attestation_challenge->data, record->attestation_challenge->length);
1418 attestation_challenge->data_length = record->attestation_challenge->length;
1419
1420 unique_id->data = dup_buffer(record->unique_id->data, record->unique_id->length);
1421 unique_id->data_length = record->unique_id->length;
1422
1423 keymaster_error_t error = extract_auth_list(record->software_enforced, software_enforced);
1424 if (error != KM_ERROR_OK) return error;
1425
1426 return extract_auth_list(record->tee_enforced, tee_enforced);
1427 }
1428
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)1429 keymaster_error_t parse_root_of_trust(const uint8_t* asn1_key_desc, size_t asn1_key_desc_len,
1430 keymaster_blob_t* verified_boot_key,
1431 keymaster_verified_boot_t* verified_boot_state,
1432 bool* device_locked) {
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()) {
1437 return TranslateLastOpenSslError();
1438 }
1439 if (!record->tee_enforced) {
1440 return KM_ERROR_INVALID_ARGUMENT;
1441 }
1442 if (!record->tee_enforced->root_of_trust) {
1443 return KM_ERROR_INVALID_ARGUMENT;
1444 }
1445 if (!record->tee_enforced->root_of_trust->verified_boot_key) {
1446 return KM_ERROR_INVALID_ARGUMENT;
1447 }
1448 KM_ROOT_OF_TRUST* root_of_trust = record->tee_enforced->root_of_trust;
1449 verified_boot_key->data = dup_buffer(root_of_trust->verified_boot_key->data,
1450 root_of_trust->verified_boot_key->length);
1451 verified_boot_key->data_length = root_of_trust->verified_boot_key->length;
1452 *verified_boot_state = static_cast<keymaster_verified_boot_t>(
1453 ASN1_ENUMERATED_get(root_of_trust->verified_boot_state));
1454 *device_locked = root_of_trust->device_locked;
1455 return KM_ERROR_OK;
1456 }
1457
1458 // Parse the EAT-encoded attestation record, placing the results in keymaster_version,
1459 // 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)1460 keymaster_error_t parse_eat_record(
1461 const uint8_t* eat_key_desc, size_t eat_key_desc_len, uint32_t* attestation_version,
1462 keymaster_security_level_t* attestation_security_level, uint32_t* keymaster_version,
1463 keymaster_security_level_t* keymaster_security_level, keymaster_blob_t* attestation_challenge,
1464 AuthorizationSet* software_enforced, AuthorizationSet* tee_enforced,
1465 keymaster_blob_t* unique_id, keymaster_blob_t* verified_boot_key,
1466 keymaster_verified_boot_t* verified_boot_state, bool* device_locked,
1467 std::vector<int64_t>* unexpected_claims) {
1468 auto [top_level_item, next_pos, error] = cppbor::parse(eat_key_desc, eat_key_desc_len);
1469 ASSERT_OR_RETURN_ERROR(top_level_item, KM_ERROR_INVALID_TAG);
1470 const cppbor::Map* eat_map = top_level_item->asMap();
1471 ASSERT_OR_RETURN_ERROR(eat_map, KM_ERROR_INVALID_TAG);
1472 bool verified_or_self_signed = false;
1473
1474 for (size_t i = 0; i < eat_map->size(); i++) {
1475 auto& [key_item, value_item] = (*eat_map)[i];
1476 const cppbor::Int* key = key_item->asInt();
1477 ASSERT_OR_RETURN_ERROR(key, (KM_ERROR_INVALID_TAG));
1478
1479 // The following values will either hold the typed value, or be null (if not the right
1480 // type).
1481 const cppbor::Int* int_value = value_item->asInt();
1482 const cppbor::Bstr* bstr_value = value_item->asBstr();
1483 const cppbor::Simple* simple_value = value_item->asSimple();
1484 const cppbor::Array* array_value = value_item->asArray();
1485 const cppbor::Map* map_value = value_item->asMap();
1486
1487 keymaster_error_t error;
1488 switch ((EatClaim)key->value()) {
1489 default:
1490 unexpected_claims->push_back(key->value());
1491 break;
1492 case EatClaim::ATTESTATION_VERSION:
1493 ASSERT_OR_RETURN_ERROR(int_value, KM_ERROR_INVALID_TAG);
1494 *attestation_version = int_value->value();
1495 break;
1496 case EatClaim::SECURITY_LEVEL:
1497 ASSERT_OR_RETURN_ERROR(int_value, KM_ERROR_INVALID_TAG);
1498 switch ((EatSecurityLevel)int_value->value()) {
1499 // TODO: Is my assumption correct that the security level of the attestation data should
1500 // always be equal to the security level of keymint, as the attestation data always
1501 // lives in the top-level module?
1502 case EatSecurityLevel::UNRESTRICTED:
1503 *keymaster_security_level = *attestation_security_level =
1504 KM_SECURITY_LEVEL_SOFTWARE;
1505 break;
1506 case EatSecurityLevel::SECURE_RESTRICTED:
1507 *keymaster_security_level = *attestation_security_level =
1508 KM_SECURITY_LEVEL_TRUSTED_ENVIRONMENT;
1509 break;
1510 case EatSecurityLevel::HARDWARE:
1511 *keymaster_security_level = *attestation_security_level =
1512 KM_SECURITY_LEVEL_STRONGBOX;
1513 break;
1514 default:
1515 return KM_ERROR_INVALID_TAG;
1516 }
1517 break;
1518 case EatClaim::KEYMASTER_VERSION:
1519 ASSERT_OR_RETURN_ERROR(int_value, KM_ERROR_INVALID_TAG);
1520 *keymaster_version = int_value->value();
1521 break;
1522 case EatClaim::SUBMODS:
1523 ASSERT_OR_RETURN_ERROR(map_value, KM_ERROR_INVALID_TAG);
1524 for (size_t j = 0; j < map_value->size(); j++) {
1525 auto& [submod_key, submod_value] = (*map_value)[j];
1526 const cppbor::Map* submod_map = submod_value->asMap();
1527 ASSERT_OR_RETURN_ERROR(submod_map, KM_ERROR_INVALID_TAG);
1528 error = parse_eat_submod(submod_map, software_enforced, tee_enforced);
1529 if (error != KM_ERROR_OK) return error;
1530 }
1531 break;
1532 case EatClaim::CTI:
1533 error = bstr_to_blob(bstr_value, unique_id);
1534 if (error != KM_ERROR_OK) return error;
1535 break;
1536 case EatClaim::NONCE:
1537 error = bstr_to_blob(bstr_value, attestation_challenge);
1538 if (error != KM_ERROR_OK) return error;
1539 break;
1540 case EatClaim::VERIFIED_BOOT_KEY:
1541 error = bstr_to_blob(bstr_value, verified_boot_key);
1542 if (error != KM_ERROR_OK) return error;
1543 break;
1544 case EatClaim::VERIFIED_BOOT_HASH:
1545 // Not parsing this for now.
1546 break;
1547 case EatClaim::DEVICE_UNIQUE_ATTESTATION:
1548 if (value_item->asSimple() == nullptr || !value_item->asSimple()->asBool()->value()) {
1549 return KM_ERROR_INVALID_TAG;
1550 }
1551 // Not parsing this for now.
1552 break;
1553 case EatClaim::DEVICE_LOCKED:
1554 ASSERT_OR_RETURN_ERROR(simple_value->asBool(), KM_ERROR_INVALID_TAG);
1555 *device_locked = simple_value->asBool()->value();
1556 break;
1557 case EatClaim::BOOT_STATE:
1558 ASSERT_OR_RETURN_ERROR(array_value, KM_ERROR_INVALID_TAG);
1559 ASSERT_OR_RETURN_ERROR(array_value->size() == 5, KM_ERROR_INVALID_TAG);
1560 ASSERT_OR_RETURN_ERROR((*array_value)[4]->asSimple()->asBool()->value() == false,
1561 KM_ERROR_INVALID_TAG);
1562 verified_or_self_signed = (*array_value)[0]->asSimple()->asBool()->value();
1563 ASSERT_OR_RETURN_ERROR(verified_or_self_signed ==
1564 (*array_value)[1]->asSimple()->asBool()->value(),
1565 KM_ERROR_INVALID_TAG);
1566 ASSERT_OR_RETURN_ERROR(verified_or_self_signed ==
1567 (*array_value)[2]->asSimple()->asBool()->value(),
1568 KM_ERROR_INVALID_TAG);
1569 ASSERT_OR_RETURN_ERROR(verified_or_self_signed ==
1570 (*array_value)[3]->asSimple()->asBool()->value(),
1571 KM_ERROR_INVALID_TAG);
1572 break;
1573 case EatClaim::OFFICIAL_BUILD:
1574 *verified_boot_state = KM_VERIFIED_BOOT_VERIFIED;
1575 break;
1576 }
1577 }
1578
1579 if (*verified_boot_state == KM_VERIFIED_BOOT_VERIFIED) {
1580 (void)(verified_boot_state);
1581 // TODO: re-enable this
1582 // ASSERT_OR_RETURN_ERROR(verified_or_self_signed, KM_ERROR_INVALID_TAG);
1583 } else {
1584 *verified_boot_state =
1585 verified_or_self_signed ? KM_VERIFIED_BOOT_SELF_SIGNED : KM_VERIFIED_BOOT_UNVERIFIED;
1586 }
1587
1588 return KM_ERROR_OK;
1589 }
1590
parse_submod_values(AuthorizationSetBuilder * set_builder,int * auth_set_security_level,const cppbor::Map * submod_map)1591 keymaster_error_t parse_submod_values(AuthorizationSetBuilder* set_builder,
1592 int* auth_set_security_level, const cppbor::Map* submod_map) {
1593 ASSERT_OR_RETURN_ERROR(set_builder, KM_ERROR_UNEXPECTED_NULL_POINTER);
1594 for (size_t i = 0; i < submod_map->size(); i++) {
1595 auto& [key_item, value_item] = (*submod_map)[i];
1596 const cppbor::Int* key_int = key_item->asInt();
1597 ASSERT_OR_RETURN_ERROR(key_int, KM_ERROR_INVALID_TAG);
1598 int key = key_int->value();
1599 keymaster_error_t error;
1600 keymaster_blob_t blob;
1601
1602 switch ((EatClaim)key) {
1603 default:
1604 return KM_ERROR_INVALID_TAG;
1605 case EatClaim::ALGORITHM:
1606 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1607 set_builder->Authorization(
1608 TAG_ALGORITHM, static_cast<keymaster_algorithm_t>(value_item->asInt()->value()));
1609 break;
1610 case EatClaim::EC_CURVE:
1611 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1612 set_builder->Authorization(
1613 TAG_EC_CURVE, static_cast<keymaster_ec_curve_t>(value_item->asInt()->value()));
1614 break;
1615 case EatClaim::USER_AUTH_TYPE:
1616 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1617 set_builder->Authorization(TAG_USER_AUTH_TYPE, static_cast<hw_authenticator_type_t>(
1618 value_item->asInt()->value()));
1619 break;
1620 case EatClaim::ORIGIN:
1621 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1622 set_builder->Authorization(
1623 TAG_ORIGIN, static_cast<keymaster_key_origin_t>(value_item->asInt()->value()));
1624 break;
1625 case EatClaim::PURPOSE:
1626 for (size_t j = 0; j < value_item->asArray()->size(); j++) {
1627 set_builder->Authorization(TAG_PURPOSE,
1628 static_cast<keymaster_purpose_t>(
1629 (*value_item->asArray())[j]->asInt()->value()));
1630 }
1631 break;
1632 case EatClaim::PADDING:
1633 for (size_t j = 0; j < value_item->asArray()->size(); j++) {
1634 set_builder->Authorization(TAG_PADDING,
1635 static_cast<keymaster_padding_t>(
1636 (*value_item->asArray())[j]->asInt()->value()));
1637 }
1638 break;
1639 case EatClaim::DIGEST:
1640 for (size_t j = 0; j < value_item->asArray()->size(); j++) {
1641 set_builder->Authorization(
1642 TAG_DIGEST,
1643 static_cast<keymaster_digest_t>((*value_item->asArray())[j]->asInt()->value()));
1644 }
1645 break;
1646 case EatClaim::BLOCK_MODE:
1647 for (size_t j = 0; j < value_item->asArray()->size(); j++) {
1648 set_builder->Authorization(TAG_BLOCK_MODE,
1649 static_cast<keymaster_block_mode_t>(
1650 (*value_item->asArray())[j]->asInt()->value()));
1651 }
1652 break;
1653 case EatClaim::KEY_SIZE:
1654 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1655 set_builder->Authorization(TAG_KEY_SIZE, value_item->asInt()->value());
1656 break;
1657 case EatClaim::AUTH_TIMEOUT:
1658 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1659 set_builder->Authorization(TAG_AUTH_TIMEOUT, value_item->asInt()->value());
1660 break;
1661 case EatClaim::OS_VERSION:
1662 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1663 set_builder->Authorization(TAG_OS_VERSION, value_item->asInt()->value());
1664 break;
1665 case EatClaim::OS_PATCHLEVEL:
1666 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1667 set_builder->Authorization(TAG_OS_PATCHLEVEL, value_item->asInt()->value());
1668 break;
1669 case EatClaim::MIN_MAC_LENGTH:
1670 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1671 set_builder->Authorization(TAG_MIN_MAC_LENGTH, value_item->asInt()->value());
1672 break;
1673 case EatClaim::BOOT_PATCHLEVEL:
1674 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1675 set_builder->Authorization(TAG_BOOT_PATCHLEVEL, value_item->asInt()->value());
1676 break;
1677 case EatClaim::VENDOR_PATCHLEVEL:
1678 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1679 set_builder->Authorization(TAG_VENDOR_PATCHLEVEL, value_item->asInt()->value());
1680 break;
1681 case EatClaim::RSA_PUBLIC_EXPONENT:
1682 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1683 set_builder->Authorization(TAG_RSA_PUBLIC_EXPONENT, value_item->asInt()->value());
1684 break;
1685 case EatClaim::ACTIVE_DATETIME:
1686 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1687 set_builder->Authorization(TAG_ACTIVE_DATETIME, value_item->asInt()->value());
1688 break;
1689 case EatClaim::ORIGINATION_EXPIRE_DATETIME:
1690 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1691 set_builder->Authorization(TAG_ORIGINATION_EXPIRE_DATETIME,
1692 value_item->asInt()->value());
1693 break;
1694 case EatClaim::USAGE_EXPIRE_DATETIME:
1695 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1696 set_builder->Authorization(TAG_USAGE_EXPIRE_DATETIME, value_item->asInt()->value());
1697 break;
1698 case EatClaim::IAT:
1699 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1700 set_builder->Authorization(TAG_CREATION_DATETIME, value_item->asInt()->value());
1701 break;
1702 case EatClaim::NO_AUTH_REQUIRED:
1703 if (value_item->asSimple() == nullptr || !value_item->asSimple()->asBool()->value()) {
1704 return KM_ERROR_INVALID_TAG;
1705 }
1706 set_builder->Authorization(TAG_NO_AUTH_REQUIRED);
1707 break;
1708 case EatClaim::ALL_APPLICATIONS:
1709 if (value_item->asSimple() == nullptr || !value_item->asSimple()->asBool()->value()) {
1710 return KM_ERROR_INVALID_TAG;
1711 }
1712 set_builder->Authorization(TAG_ALL_APPLICATIONS);
1713 break;
1714 case EatClaim::ROLLBACK_RESISTANT:
1715 if (value_item->asSimple() == nullptr || !value_item->asSimple()->asBool()->value()) {
1716 return KM_ERROR_INVALID_TAG;
1717 }
1718 set_builder->Authorization(TAG_ROLLBACK_RESISTANT);
1719 break;
1720 case EatClaim::ALLOW_WHILE_ON_BODY:
1721 if (value_item->asSimple() == nullptr || !value_item->asSimple()->asBool()->value()) {
1722 return KM_ERROR_INVALID_TAG;
1723 }
1724 set_builder->Authorization(TAG_ALLOW_WHILE_ON_BODY);
1725 break;
1726 case EatClaim::UNLOCKED_DEVICE_REQUIRED:
1727 if (value_item->asSimple() == nullptr || !value_item->asSimple()->asBool()->value()) {
1728 return KM_ERROR_INVALID_TAG;
1729 }
1730 set_builder->Authorization(TAG_UNLOCKED_DEVICE_REQUIRED);
1731 break;
1732 case EatClaim::CALLER_NONCE:
1733 if (value_item->asSimple() == nullptr || !value_item->asSimple()->asBool()->value()) {
1734 return KM_ERROR_INVALID_TAG;
1735 }
1736 set_builder->Authorization(TAG_CALLER_NONCE);
1737 break;
1738 case EatClaim::TRUSTED_CONFIRMATION_REQUIRED:
1739 if (value_item->asSimple() == nullptr || !value_item->asSimple()->asBool()->value()) {
1740 return KM_ERROR_INVALID_TAG;
1741 }
1742 set_builder->Authorization(TAG_TRUSTED_CONFIRMATION_REQUIRED);
1743 break;
1744 case EatClaim::EARLY_BOOT_ONLY:
1745 if (value_item->asSimple() == nullptr || !value_item->asSimple()->asBool()->value()) {
1746 return KM_ERROR_INVALID_TAG;
1747 }
1748 set_builder->Authorization(TAG_EARLY_BOOT_ONLY);
1749 break;
1750 case EatClaim::IDENTITY_CREDENTIAL_KEY:
1751 if (value_item->asSimple() == nullptr || !value_item->asSimple()->asBool()->value()) {
1752 return KM_ERROR_INVALID_TAG;
1753 }
1754 set_builder->Authorization(TAG_IDENTITY_CREDENTIAL_KEY);
1755 break;
1756 case EatClaim::STORAGE_KEY:
1757 if (value_item->asSimple() == nullptr || !value_item->asSimple()->asBool()->value()) {
1758 return KM_ERROR_INVALID_TAG;
1759 }
1760 set_builder->Authorization(TAG_STORAGE_KEY);
1761 break;
1762 case EatClaim::TRUSTED_USER_PRESENCE_REQUIRED:
1763 if (value_item->asSimple() == nullptr || !value_item->asSimple()->asBool()->value()) {
1764 return KM_ERROR_INVALID_TAG;
1765 }
1766 set_builder->Authorization(TAG_TRUSTED_USER_PRESENCE_REQUIRED);
1767 break;
1768 case EatClaim::DEVICE_UNIQUE_ATTESTATION:
1769 if (value_item->asSimple() == nullptr || !value_item->asSimple()->asBool()->value()) {
1770 return KM_ERROR_INVALID_TAG;
1771 }
1772 set_builder->Authorization(TAG_DEVICE_UNIQUE_ATTESTATION);
1773 break;
1774 case EatClaim::APPLICATION_ID:
1775 error = bstr_to_blob(value_item->asBstr(), &blob);
1776 if (error != KM_ERROR_OK) return error;
1777 set_builder->Authorization(TAG_APPLICATION_ID, blob);
1778 break;
1779 case EatClaim::ATTESTATION_APPLICATION_ID:
1780 error = bstr_to_blob(value_item->asBstr(), &blob);
1781 if (error != KM_ERROR_OK) return error;
1782 set_builder->Authorization(TAG_ATTESTATION_APPLICATION_ID, blob);
1783 break;
1784 case EatClaim::ATTESTATION_ID_BRAND:
1785 error = bstr_to_blob(value_item->asBstr(), &blob);
1786 if (error != KM_ERROR_OK) return error;
1787 set_builder->Authorization(TAG_ATTESTATION_ID_BRAND, blob);
1788 break;
1789 case EatClaim::ATTESTATION_ID_DEVICE:
1790 error = bstr_to_blob(value_item->asBstr(), &blob);
1791 if (error != KM_ERROR_OK) return error;
1792 set_builder->Authorization(TAG_ATTESTATION_ID_DEVICE, blob);
1793 break;
1794 case EatClaim::ATTESTATION_ID_PRODUCT:
1795 error = bstr_to_blob(value_item->asBstr(), &blob);
1796 if (error != KM_ERROR_OK) return error;
1797 set_builder->Authorization(TAG_ATTESTATION_ID_PRODUCT, blob);
1798 break;
1799 case EatClaim::ATTESTATION_ID_SERIAL:
1800 error = bstr_to_blob(value_item->asBstr(), &blob);
1801 if (error != KM_ERROR_OK) return error;
1802 set_builder->Authorization(TAG_ATTESTATION_ID_SERIAL, blob);
1803 break;
1804 case EatClaim::UEID:
1805 error = ueid_to_imei_blob(value_item->asBstr(), &blob);
1806 if (error != KM_ERROR_OK) return error;
1807 set_builder->Authorization(TAG_ATTESTATION_ID_IMEI, blob);
1808 break;
1809 case EatClaim::ATTESTATION_ID_MEID:
1810 error = bstr_to_blob(value_item->asBstr(), &blob);
1811 if (error != KM_ERROR_OK) return error;
1812 set_builder->Authorization(TAG_ATTESTATION_ID_MEID, blob);
1813 break;
1814 case EatClaim::ATTESTATION_ID_MANUFACTURER:
1815 error = bstr_to_blob(value_item->asBstr(), &blob);
1816 if (error != KM_ERROR_OK) return error;
1817 set_builder->Authorization(TAG_ATTESTATION_ID_MANUFACTURER, blob);
1818 break;
1819 case EatClaim::ATTESTATION_ID_MODEL:
1820 error = bstr_to_blob(value_item->asBstr(), &blob);
1821 if (error != KM_ERROR_OK) return error;
1822 set_builder->Authorization(TAG_ATTESTATION_ID_MODEL, blob);
1823 break;
1824 case EatClaim::CONFIRMATION_TOKEN:
1825 error = bstr_to_blob(value_item->asBstr(), &blob);
1826 if (error != KM_ERROR_OK) return error;
1827 set_builder->Authorization(TAG_CONFIRMATION_TOKEN, blob);
1828 break;
1829 case EatClaim::SECURITY_LEVEL:
1830 ASSERT_OR_RETURN_ERROR(value_item->asInt(), KM_ERROR_INVALID_TAG);
1831 *auth_set_security_level = value_item->asInt()->value();
1832 }
1833 }
1834
1835 return KM_ERROR_OK;
1836 }
1837
parse_eat_submod(const cppbor::Map * submod_values,AuthorizationSet * software_enforced,AuthorizationSet * tee_enforced)1838 keymaster_error_t parse_eat_submod(const cppbor::Map* submod_values,
1839 AuthorizationSet* software_enforced,
1840 AuthorizationSet* tee_enforced) {
1841 AuthorizationSetBuilder auth_set_builder;
1842 int auth_set_security_level = 0;
1843 keymaster_error_t error =
1844 parse_submod_values(&auth_set_builder, &auth_set_security_level, submod_values);
1845 if (error) return error;
1846 switch ((EatSecurityLevel)auth_set_security_level) {
1847 case EatSecurityLevel::HARDWARE:
1848 // Hardware attestation should never occur in a submod of another EAT.
1849 [[fallthrough]];
1850 default:
1851 return KM_ERROR_INVALID_TAG;
1852 case EatSecurityLevel::UNRESTRICTED:
1853 *software_enforced = AuthorizationSet(auth_set_builder);
1854 break;
1855 case EatSecurityLevel::SECURE_RESTRICTED:
1856 *tee_enforced = AuthorizationSet(auth_set_builder);
1857 break;
1858 }
1859
1860 return KM_ERROR_OK;
1861 }
1862 } // namespace keymaster
1863