David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 2019, 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 | #define LOG_TAG "IdentityCredential" |
| 18 | |
| 19 | #include "IdentityCredential.h" |
| 20 | #include "IdentityCredentialStore.h" |
| 21 | #include "Util.h" |
| 22 | |
| 23 | #include <android/hardware/identity/support/IdentityCredentialSupport.h> |
| 24 | |
| 25 | #include <string.h> |
| 26 | |
| 27 | #include <android-base/logging.h> |
| 28 | |
| 29 | #include <cppbor.h> |
| 30 | #include <cppbor_parse.h> |
| 31 | |
| 32 | namespace aidl::android::hardware::identity { |
| 33 | |
| 34 | using ::aidl::android::hardware::keymaster::Timestamp; |
| 35 | using ::std::optional; |
| 36 | |
| 37 | using namespace ::android::hardware::identity; |
| 38 | |
| 39 | int IdentityCredential::initialize() { |
| 40 | auto [item, _, message] = cppbor::parse(credentialData_); |
| 41 | if (item == nullptr) { |
| 42 | LOG(ERROR) << "CredentialData is not valid CBOR: " << message; |
| 43 | return IIdentityCredentialStore::STATUS_INVALID_DATA; |
| 44 | } |
| 45 | |
| 46 | const cppbor::Array* arrayItem = item->asArray(); |
| 47 | if (arrayItem == nullptr || arrayItem->size() != 3) { |
| 48 | LOG(ERROR) << "CredentialData is not an array with three elements"; |
| 49 | return IIdentityCredentialStore::STATUS_INVALID_DATA; |
| 50 | } |
| 51 | |
| 52 | const cppbor::Tstr* docTypeItem = (*arrayItem)[0]->asTstr(); |
| 53 | const cppbor::Bool* testCredentialItem = |
| 54 | ((*arrayItem)[1]->asSimple() != nullptr ? ((*arrayItem)[1]->asSimple()->asBool()) |
| 55 | : nullptr); |
| 56 | const cppbor::Bstr* encryptedCredentialKeysItem = (*arrayItem)[2]->asBstr(); |
| 57 | if (docTypeItem == nullptr || testCredentialItem == nullptr || |
| 58 | encryptedCredentialKeysItem == nullptr) { |
| 59 | LOG(ERROR) << "CredentialData unexpected item types"; |
| 60 | return IIdentityCredentialStore::STATUS_INVALID_DATA; |
| 61 | } |
| 62 | |
| 63 | docType_ = docTypeItem->value(); |
| 64 | testCredential_ = testCredentialItem->value(); |
| 65 | |
| 66 | vector<uint8_t> hardwareBoundKey; |
| 67 | if (testCredential_) { |
| 68 | hardwareBoundKey = support::getTestHardwareBoundKey(); |
| 69 | } else { |
| 70 | hardwareBoundKey = getHardwareBoundKey(); |
| 71 | } |
| 72 | |
| 73 | const vector<uint8_t>& encryptedCredentialKeys = encryptedCredentialKeysItem->value(); |
| 74 | const vector<uint8_t> docTypeVec(docType_.begin(), docType_.end()); |
| 75 | optional<vector<uint8_t>> decryptedCredentialKeys = |
| 76 | support::decryptAes128Gcm(hardwareBoundKey, encryptedCredentialKeys, docTypeVec); |
| 77 | if (!decryptedCredentialKeys) { |
| 78 | LOG(ERROR) << "Error decrypting CredentialKeys"; |
| 79 | return IIdentityCredentialStore::STATUS_INVALID_DATA; |
| 80 | } |
| 81 | |
| 82 | auto [dckItem, dckPos, dckMessage] = cppbor::parse(decryptedCredentialKeys.value()); |
| 83 | if (dckItem == nullptr) { |
| 84 | LOG(ERROR) << "Decrypted CredentialKeys is not valid CBOR: " << dckMessage; |
| 85 | return IIdentityCredentialStore::STATUS_INVALID_DATA; |
| 86 | } |
| 87 | const cppbor::Array* dckArrayItem = dckItem->asArray(); |
| 88 | if (dckArrayItem == nullptr || dckArrayItem->size() != 2) { |
| 89 | LOG(ERROR) << "Decrypted CredentialKeys is not an array with two elements"; |
| 90 | return IIdentityCredentialStore::STATUS_INVALID_DATA; |
| 91 | } |
| 92 | const cppbor::Bstr* storageKeyItem = (*dckArrayItem)[0]->asBstr(); |
| 93 | const cppbor::Bstr* credentialPrivKeyItem = (*dckArrayItem)[1]->asBstr(); |
| 94 | if (storageKeyItem == nullptr || credentialPrivKeyItem == nullptr) { |
| 95 | LOG(ERROR) << "CredentialKeys unexpected item types"; |
| 96 | return IIdentityCredentialStore::STATUS_INVALID_DATA; |
| 97 | } |
| 98 | storageKey_ = storageKeyItem->value(); |
| 99 | credentialPrivKey_ = credentialPrivKeyItem->value(); |
| 100 | |
| 101 | return IIdentityCredentialStore::STATUS_OK; |
| 102 | } |
| 103 | |
| 104 | ndk::ScopedAStatus IdentityCredential::deleteCredential( |
| 105 | vector<int8_t>* outProofOfDeletionSignature) { |
| 106 | cppbor::Array array = {"ProofOfDeletion", docType_, testCredential_}; |
| 107 | vector<uint8_t> proofOfDeletion = array.encode(); |
| 108 | |
| 109 | optional<vector<uint8_t>> signature = support::coseSignEcDsa(credentialPrivKey_, |
| 110 | proofOfDeletion, // payload |
| 111 | {}, // additionalData |
| 112 | {}); // certificateChain |
| 113 | if (!signature) { |
| 114 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 115 | IIdentityCredentialStore::STATUS_FAILED, "Error signing data")); |
| 116 | } |
| 117 | |
| 118 | *outProofOfDeletionSignature = byteStringToSigned(signature.value()); |
| 119 | return ndk::ScopedAStatus::ok(); |
| 120 | } |
| 121 | |
| 122 | ndk::ScopedAStatus IdentityCredential::createEphemeralKeyPair(vector<int8_t>* outKeyPair) { |
| 123 | optional<vector<uint8_t>> kp = support::createEcKeyPair(); |
| 124 | if (!kp) { |
| 125 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 126 | IIdentityCredentialStore::STATUS_FAILED, "Error creating ephemeral key pair")); |
| 127 | } |
| 128 | |
| 129 | // Stash public key of this key-pair for later check in startRetrieval(). |
| 130 | optional<vector<uint8_t>> publicKey = support::ecKeyPairGetPublicKey(kp.value()); |
| 131 | if (!publicKey) { |
| 132 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 133 | IIdentityCredentialStore::STATUS_FAILED, |
| 134 | "Error getting public part of ephemeral key pair")); |
| 135 | } |
| 136 | ephemeralPublicKey_ = publicKey.value(); |
| 137 | |
| 138 | *outKeyPair = byteStringToSigned(kp.value()); |
| 139 | return ndk::ScopedAStatus::ok(); |
| 140 | } |
| 141 | |
| 142 | ndk::ScopedAStatus IdentityCredential::setReaderEphemeralPublicKey( |
| 143 | const vector<int8_t>& publicKey) { |
| 144 | readerPublicKey_ = byteStringToUnsigned(publicKey); |
| 145 | return ndk::ScopedAStatus::ok(); |
| 146 | } |
| 147 | |
| 148 | ndk::ScopedAStatus IdentityCredential::createAuthChallenge(int64_t* outChallenge) { |
| 149 | uint64_t challenge = 0; |
| 150 | while (challenge == 0) { |
| 151 | optional<vector<uint8_t>> bytes = support::getRandom(8); |
| 152 | if (!bytes) { |
| 153 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 154 | IIdentityCredentialStore::STATUS_FAILED, |
| 155 | "Error getting random data for challenge")); |
| 156 | } |
| 157 | |
| 158 | challenge = 0; |
| 159 | for (size_t n = 0; n < bytes.value().size(); n++) { |
| 160 | challenge |= ((bytes.value())[n] << (n * 8)); |
| 161 | } |
| 162 | } |
| 163 | |
| 164 | *outChallenge = challenge; |
| 165 | return ndk::ScopedAStatus::ok(); |
| 166 | } |
| 167 | |
| 168 | // TODO: this could be a lot faster if we did all the splitting and pubkey extraction |
| 169 | // ahead of time. |
| 170 | bool checkReaderAuthentication(const SecureAccessControlProfile& profile, |
| 171 | const vector<uint8_t>& readerCertificateChain) { |
| 172 | optional<vector<uint8_t>> acpPubKey = support::certificateChainGetTopMostKey( |
| 173 | byteStringToUnsigned(profile.readerCertificate.encodedCertificate)); |
| 174 | if (!acpPubKey) { |
| 175 | LOG(ERROR) << "Error extracting public key from readerCertificate in profile"; |
| 176 | return false; |
| 177 | } |
| 178 | |
| 179 | optional<vector<vector<uint8_t>>> certificatesInChain = |
| 180 | support::certificateChainSplit(readerCertificateChain); |
| 181 | if (!certificatesInChain) { |
| 182 | LOG(ERROR) << "Error splitting readerCertificateChain"; |
| 183 | return false; |
| 184 | } |
| 185 | for (const vector<uint8_t>& certInChain : certificatesInChain.value()) { |
| 186 | optional<vector<uint8_t>> certPubKey = support::certificateChainGetTopMostKey(certInChain); |
| 187 | if (!certPubKey) { |
| 188 | LOG(ERROR) |
| 189 | << "Error extracting public key from certificate in chain presented by reader"; |
| 190 | return false; |
| 191 | } |
| 192 | if (acpPubKey.value() == certPubKey.value()) { |
| 193 | return true; |
| 194 | } |
| 195 | } |
| 196 | return false; |
| 197 | } |
| 198 | |
| 199 | Timestamp clockGetTime() { |
| 200 | struct timespec time; |
| 201 | clock_gettime(CLOCK_MONOTONIC, &time); |
| 202 | Timestamp ts; |
| 203 | ts.milliSeconds = time.tv_sec * 1000 + time.tv_nsec / 1000000; |
| 204 | return ts; |
| 205 | } |
| 206 | |
| 207 | bool checkUserAuthentication(const SecureAccessControlProfile& profile, |
| 208 | const HardwareAuthToken& authToken, uint64_t authChallenge) { |
| 209 | if (profile.secureUserId != authToken.userId) { |
| 210 | LOG(ERROR) << "secureUserId in profile (" << profile.secureUserId |
| 211 | << ") differs from userId in authToken (" << authToken.userId << ")"; |
| 212 | return false; |
| 213 | } |
| 214 | |
| 215 | if (profile.timeoutMillis == 0) { |
| 216 | if (authToken.challenge == 0) { |
| 217 | LOG(ERROR) << "No challenge in authToken"; |
| 218 | return false; |
| 219 | } |
| 220 | |
| 221 | if (authToken.challenge != int64_t(authChallenge)) { |
| 222 | LOG(ERROR) << "Challenge in authToken doesn't match the challenge we created"; |
| 223 | return false; |
| 224 | } |
| 225 | return true; |
| 226 | } |
| 227 | |
| 228 | // Note that the Epoch for timestamps in HardwareAuthToken is at the |
| 229 | // discretion of the vendor: |
| 230 | // |
| 231 | // "[...] since some starting point (generally the most recent device |
| 232 | // boot) which all of the applications within one secure environment |
| 233 | // must agree upon." |
| 234 | // |
| 235 | // Therefore, if this software implementation is used on a device which isn't |
| 236 | // the emulator then the assumption that the epoch is the same as used in |
| 237 | // clockGetTime above will not hold. This is OK as this software |
| 238 | // implementation should never be used on a real device. |
| 239 | // |
| 240 | Timestamp now = clockGetTime(); |
| 241 | if (authToken.timestamp.milliSeconds > now.milliSeconds) { |
| 242 | LOG(ERROR) << "Timestamp in authToken (" << authToken.timestamp.milliSeconds |
| 243 | << ") is in the future (now: " << now.milliSeconds << ")"; |
| 244 | return false; |
| 245 | } |
| 246 | if (now.milliSeconds > authToken.timestamp.milliSeconds + profile.timeoutMillis) { |
| 247 | LOG(ERROR) << "Deadline for authToken (" << authToken.timestamp.milliSeconds << " + " |
| 248 | << profile.timeoutMillis << " = " |
| 249 | << (authToken.timestamp.milliSeconds + profile.timeoutMillis) |
| 250 | << ") is in the past (now: " << now.milliSeconds << ")"; |
| 251 | return false; |
| 252 | } |
| 253 | return true; |
| 254 | } |
| 255 | |
| 256 | ndk::ScopedAStatus IdentityCredential::startRetrieval( |
| 257 | const vector<SecureAccessControlProfile>& accessControlProfiles, |
| 258 | const HardwareAuthToken& authToken, const vector<int8_t>& itemsRequestS, |
David Zeuthen | e35797f | 2020-02-27 14:25:54 -0500 | [diff] [blame] | 259 | const vector<int8_t>& signingKeyBlobS, const vector<int8_t>& sessionTranscriptS, |
| 260 | const vector<int8_t>& readerSignatureS, const vector<int32_t>& requestCounts) { |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 261 | auto sessionTranscript = byteStringToUnsigned(sessionTranscriptS); |
| 262 | auto itemsRequest = byteStringToUnsigned(itemsRequestS); |
| 263 | auto readerSignature = byteStringToUnsigned(readerSignatureS); |
| 264 | |
| 265 | if (sessionTranscript.size() > 0) { |
| 266 | auto [item, _, message] = cppbor::parse(sessionTranscript); |
| 267 | if (item == nullptr) { |
| 268 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 269 | IIdentityCredentialStore::STATUS_INVALID_DATA, |
| 270 | "SessionTranscript contains invalid CBOR")); |
| 271 | } |
| 272 | sessionTranscriptItem_ = std::move(item); |
| 273 | } |
| 274 | if (numStartRetrievalCalls_ > 0) { |
| 275 | if (sessionTranscript_ != sessionTranscript) { |
| 276 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 277 | IIdentityCredentialStore::STATUS_SESSION_TRANSCRIPT_MISMATCH, |
| 278 | "Passed-in SessionTranscript doesn't match previously used SessionTranscript")); |
| 279 | } |
| 280 | } |
| 281 | sessionTranscript_ = sessionTranscript; |
| 282 | |
| 283 | // If there is a signature, validate that it was made with the top-most key in the |
| 284 | // certificate chain embedded in the COSE_Sign1 structure. |
| 285 | optional<vector<uint8_t>> readerCertificateChain; |
| 286 | if (readerSignature.size() > 0) { |
| 287 | readerCertificateChain = support::coseSignGetX5Chain(readerSignature); |
| 288 | if (!readerCertificateChain) { |
| 289 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 290 | IIdentityCredentialStore::STATUS_READER_SIGNATURE_CHECK_FAILED, |
| 291 | "Unable to get reader certificate chain from COSE_Sign1")); |
| 292 | } |
| 293 | |
| 294 | if (!support::certificateChainValidate(readerCertificateChain.value())) { |
| 295 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 296 | IIdentityCredentialStore::STATUS_READER_SIGNATURE_CHECK_FAILED, |
| 297 | "Error validating reader certificate chain")); |
| 298 | } |
| 299 | |
| 300 | optional<vector<uint8_t>> readerPublicKey = |
| 301 | support::certificateChainGetTopMostKey(readerCertificateChain.value()); |
| 302 | if (!readerPublicKey) { |
| 303 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 304 | IIdentityCredentialStore::STATUS_READER_SIGNATURE_CHECK_FAILED, |
| 305 | "Unable to get public key from reader certificate chain")); |
| 306 | } |
| 307 | |
| 308 | const vector<uint8_t>& itemsRequestBytes = itemsRequest; |
| 309 | vector<uint8_t> dataThatWasSigned = cppbor::Array() |
| 310 | .add("ReaderAuthentication") |
| 311 | .add(sessionTranscriptItem_->clone()) |
| 312 | .add(cppbor::Semantic(24, itemsRequestBytes)) |
| 313 | .encode(); |
| 314 | if (!support::coseCheckEcDsaSignature(readerSignature, |
| 315 | dataThatWasSigned, // detached content |
| 316 | readerPublicKey.value())) { |
| 317 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 318 | IIdentityCredentialStore::STATUS_READER_SIGNATURE_CHECK_FAILED, |
| 319 | "readerSignature check failed")); |
| 320 | } |
| 321 | } |
| 322 | |
| 323 | // Here's where we would validate the passed-in |authToken| to assure ourselves |
| 324 | // that it comes from the e.g. biometric hardware and wasn't made up by an attacker. |
| 325 | // |
| 326 | // However this involves calculating the MAC. However this requires access |
| 327 | // to the key needed to a pre-shared key which we don't have... |
| 328 | // |
| 329 | |
| 330 | // To prevent replay-attacks, we check that the public part of the ephemeral |
| 331 | // key we previously created, is present in the DeviceEngagement part of |
| 332 | // SessionTranscript as a COSE_Key, in uncompressed form. |
| 333 | // |
| 334 | // We do this by just searching for the X and Y coordinates. |
| 335 | if (sessionTranscript.size() > 0) { |
| 336 | const cppbor::Array* array = sessionTranscriptItem_->asArray(); |
| 337 | if (array == nullptr || array->size() != 2) { |
| 338 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 339 | IIdentityCredentialStore::STATUS_EPHEMERAL_PUBLIC_KEY_NOT_FOUND, |
| 340 | "SessionTranscript is not an array with two items")); |
| 341 | } |
| 342 | const cppbor::Semantic* taggedEncodedDE = (*array)[0]->asSemantic(); |
| 343 | if (taggedEncodedDE == nullptr || taggedEncodedDE->value() != 24) { |
| 344 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 345 | IIdentityCredentialStore::STATUS_EPHEMERAL_PUBLIC_KEY_NOT_FOUND, |
| 346 | "First item in SessionTranscript array is not a " |
| 347 | "semantic with value 24")); |
| 348 | } |
| 349 | const cppbor::Bstr* encodedDE = (taggedEncodedDE->child())->asBstr(); |
| 350 | if (encodedDE == nullptr) { |
| 351 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 352 | IIdentityCredentialStore::STATUS_EPHEMERAL_PUBLIC_KEY_NOT_FOUND, |
| 353 | "Child of semantic in first item in SessionTranscript " |
| 354 | "array is not a bstr")); |
| 355 | } |
| 356 | const vector<uint8_t>& bytesDE = encodedDE->value(); |
| 357 | |
| 358 | auto [getXYSuccess, ePubX, ePubY] = support::ecPublicKeyGetXandY(ephemeralPublicKey_); |
| 359 | if (!getXYSuccess) { |
| 360 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 361 | IIdentityCredentialStore::STATUS_EPHEMERAL_PUBLIC_KEY_NOT_FOUND, |
| 362 | "Error extracting X and Y from ePub")); |
| 363 | } |
| 364 | if (sessionTranscript.size() > 0 && |
| 365 | !(memmem(bytesDE.data(), bytesDE.size(), ePubX.data(), ePubX.size()) != nullptr && |
| 366 | memmem(bytesDE.data(), bytesDE.size(), ePubY.data(), ePubY.size()) != nullptr)) { |
| 367 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 368 | IIdentityCredentialStore::STATUS_EPHEMERAL_PUBLIC_KEY_NOT_FOUND, |
| 369 | "Did not find ephemeral public key's X and Y coordinates in " |
| 370 | "SessionTranscript (make sure leading zeroes are not used)")); |
| 371 | } |
| 372 | } |
| 373 | |
| 374 | // itemsRequest: If non-empty, contains request data that may be signed by the |
| 375 | // reader. The content can be defined in the way appropriate for the |
| 376 | // credential, but there are three requirements that must be met to work with |
| 377 | // this HAL: |
| 378 | if (itemsRequest.size() > 0) { |
| 379 | // 1. The content must be a CBOR-encoded structure. |
| 380 | auto [item, _, message] = cppbor::parse(itemsRequest); |
| 381 | if (item == nullptr) { |
| 382 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 383 | IIdentityCredentialStore::STATUS_INVALID_ITEMS_REQUEST_MESSAGE, |
| 384 | "Error decoding CBOR in itemsRequest")); |
| 385 | } |
| 386 | |
| 387 | // 2. The CBOR structure must be a map. |
| 388 | const cppbor::Map* map = item->asMap(); |
| 389 | if (map == nullptr) { |
| 390 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 391 | IIdentityCredentialStore::STATUS_INVALID_ITEMS_REQUEST_MESSAGE, |
| 392 | "itemsRequest is not a CBOR map")); |
| 393 | } |
| 394 | |
| 395 | // 3. The map must contain a key "nameSpaces" whose value contains a map, as described in |
| 396 | // the example below. |
| 397 | // |
| 398 | // NameSpaces = { |
| 399 | // + NameSpace => DataElements ; Requested data elements for each NameSpace |
| 400 | // } |
| 401 | // |
| 402 | // NameSpace = tstr |
| 403 | // |
| 404 | // DataElements = { |
| 405 | // + DataElement => IntentToRetain |
| 406 | // } |
| 407 | // |
| 408 | // DataElement = tstr |
| 409 | // IntentToRetain = bool |
| 410 | // |
| 411 | // Here's an example of an |itemsRequest| CBOR value satisfying above requirements 1. |
| 412 | // through 3.: |
| 413 | // |
| 414 | // { |
| 415 | // 'docType' : 'org.iso.18013-5.2019', |
| 416 | // 'nameSpaces' : { |
| 417 | // 'org.iso.18013-5.2019' : { |
| 418 | // 'Last name' : false, |
| 419 | // 'Birth date' : false, |
| 420 | // 'First name' : false, |
| 421 | // 'Home address' : true |
| 422 | // }, |
| 423 | // 'org.aamva.iso.18013-5.2019' : { |
| 424 | // 'Real Id' : false |
| 425 | // } |
| 426 | // } |
| 427 | // } |
| 428 | // |
| 429 | const cppbor::Map* nsMap = nullptr; |
| 430 | for (size_t n = 0; n < map->size(); n++) { |
| 431 | const auto& [keyItem, valueItem] = (*map)[n]; |
| 432 | if (keyItem->type() == cppbor::TSTR && keyItem->asTstr()->value() == "nameSpaces" && |
| 433 | valueItem->type() == cppbor::MAP) { |
| 434 | nsMap = valueItem->asMap(); |
| 435 | break; |
| 436 | } |
| 437 | } |
| 438 | if (nsMap == nullptr) { |
| 439 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 440 | IIdentityCredentialStore::STATUS_INVALID_ITEMS_REQUEST_MESSAGE, |
| 441 | "No nameSpaces map in top-most map")); |
| 442 | } |
| 443 | |
| 444 | for (size_t n = 0; n < nsMap->size(); n++) { |
| 445 | auto [nsKeyItem, nsValueItem] = (*nsMap)[n]; |
| 446 | const cppbor::Tstr* nsKey = nsKeyItem->asTstr(); |
| 447 | const cppbor::Map* nsInnerMap = nsValueItem->asMap(); |
| 448 | if (nsKey == nullptr || nsInnerMap == nullptr) { |
| 449 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 450 | IIdentityCredentialStore::STATUS_INVALID_ITEMS_REQUEST_MESSAGE, |
| 451 | "Type mismatch in nameSpaces map")); |
| 452 | } |
| 453 | string requestedNamespace = nsKey->value(); |
| 454 | vector<string> requestedKeys; |
| 455 | for (size_t m = 0; m < nsInnerMap->size(); m++) { |
| 456 | const auto& [innerMapKeyItem, innerMapValueItem] = (*nsInnerMap)[m]; |
| 457 | const cppbor::Tstr* nameItem = innerMapKeyItem->asTstr(); |
| 458 | const cppbor::Simple* simple = innerMapValueItem->asSimple(); |
| 459 | const cppbor::Bool* intentToRetainItem = |
| 460 | (simple != nullptr) ? simple->asBool() : nullptr; |
| 461 | if (nameItem == nullptr || intentToRetainItem == nullptr) { |
| 462 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 463 | IIdentityCredentialStore::STATUS_INVALID_ITEMS_REQUEST_MESSAGE, |
| 464 | "Type mismatch in value in nameSpaces map")); |
| 465 | } |
| 466 | requestedKeys.push_back(nameItem->value()); |
| 467 | } |
| 468 | requestedNameSpacesAndNames_[requestedNamespace] = requestedKeys; |
| 469 | } |
| 470 | } |
| 471 | |
| 472 | // Finally, validate all the access control profiles in the requestData. |
| 473 | bool haveAuthToken = (authToken.mac.size() > 0); |
| 474 | for (const auto& profile : accessControlProfiles) { |
| 475 | if (!secureAccessControlProfileCheckMac(profile, storageKey_)) { |
| 476 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 477 | IIdentityCredentialStore::STATUS_INVALID_DATA, |
| 478 | "Error checking MAC for profile")); |
| 479 | } |
| 480 | int accessControlCheck = IIdentityCredentialStore::STATUS_OK; |
| 481 | if (profile.userAuthenticationRequired) { |
| 482 | if (!haveAuthToken || !checkUserAuthentication(profile, authToken, authChallenge_)) { |
| 483 | accessControlCheck = IIdentityCredentialStore::STATUS_USER_AUTHENTICATION_FAILED; |
| 484 | } |
| 485 | } else if (profile.readerCertificate.encodedCertificate.size() > 0) { |
| 486 | if (!readerCertificateChain || |
| 487 | !checkReaderAuthentication(profile, readerCertificateChain.value())) { |
| 488 | accessControlCheck = IIdentityCredentialStore::STATUS_READER_AUTHENTICATION_FAILED; |
| 489 | } |
| 490 | } |
| 491 | profileIdToAccessCheckResult_[profile.id] = accessControlCheck; |
| 492 | } |
| 493 | |
| 494 | deviceNameSpacesMap_ = cppbor::Map(); |
| 495 | currentNameSpaceDeviceNameSpacesMap_ = cppbor::Map(); |
| 496 | |
| 497 | requestCountsRemaining_ = requestCounts; |
| 498 | currentNameSpace_ = ""; |
| 499 | |
| 500 | itemsRequest_ = itemsRequest; |
David Zeuthen | e35797f | 2020-02-27 14:25:54 -0500 | [diff] [blame] | 501 | signingKeyBlob_ = byteStringToUnsigned(signingKeyBlobS); |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 502 | |
| 503 | numStartRetrievalCalls_ += 1; |
| 504 | return ndk::ScopedAStatus::ok(); |
| 505 | } |
| 506 | |
| 507 | ndk::ScopedAStatus IdentityCredential::startRetrieveEntryValue( |
| 508 | const string& nameSpace, const string& name, int32_t entrySize, |
| 509 | const vector<int32_t>& accessControlProfileIds) { |
| 510 | if (name.empty()) { |
| 511 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 512 | IIdentityCredentialStore::STATUS_INVALID_DATA, "Name cannot be empty")); |
| 513 | } |
| 514 | if (nameSpace.empty()) { |
| 515 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 516 | IIdentityCredentialStore::STATUS_INVALID_DATA, "Name space cannot be empty")); |
| 517 | } |
| 518 | |
| 519 | if (requestCountsRemaining_.size() == 0) { |
| 520 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 521 | IIdentityCredentialStore::STATUS_INVALID_DATA, |
| 522 | "No more name spaces left to go through")); |
| 523 | } |
| 524 | |
| 525 | if (currentNameSpace_ == "") { |
| 526 | // First call. |
| 527 | currentNameSpace_ = nameSpace; |
| 528 | } |
| 529 | |
| 530 | if (nameSpace == currentNameSpace_) { |
| 531 | // Same namespace. |
| 532 | if (requestCountsRemaining_[0] == 0) { |
| 533 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 534 | IIdentityCredentialStore::STATUS_INVALID_DATA, |
| 535 | "No more entries to be retrieved in current name space")); |
| 536 | } |
| 537 | requestCountsRemaining_[0] -= 1; |
| 538 | } else { |
| 539 | // New namespace. |
| 540 | if (requestCountsRemaining_[0] != 0) { |
| 541 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 542 | IIdentityCredentialStore::STATUS_INVALID_DATA, |
| 543 | "Moved to new name space but one or more entries need to be retrieved " |
| 544 | "in current name space")); |
| 545 | } |
| 546 | if (currentNameSpaceDeviceNameSpacesMap_.size() > 0) { |
| 547 | deviceNameSpacesMap_.add(currentNameSpace_, |
| 548 | std::move(currentNameSpaceDeviceNameSpacesMap_)); |
| 549 | } |
| 550 | currentNameSpaceDeviceNameSpacesMap_ = cppbor::Map(); |
| 551 | |
| 552 | requestCountsRemaining_.erase(requestCountsRemaining_.begin()); |
| 553 | currentNameSpace_ = nameSpace; |
| 554 | } |
| 555 | |
| 556 | // It's permissible to have an empty itemsRequest... but if non-empty you can |
| 557 | // only request what was specified in said itemsRequest. Enforce that. |
| 558 | if (itemsRequest_.size() > 0) { |
| 559 | const auto& it = requestedNameSpacesAndNames_.find(nameSpace); |
| 560 | if (it == requestedNameSpacesAndNames_.end()) { |
| 561 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 562 | IIdentityCredentialStore::STATUS_NOT_IN_REQUEST_MESSAGE, |
| 563 | "Name space was not requested in startRetrieval")); |
| 564 | } |
| 565 | const auto& dataItemNames = it->second; |
| 566 | if (std::find(dataItemNames.begin(), dataItemNames.end(), name) == dataItemNames.end()) { |
| 567 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 568 | IIdentityCredentialStore::STATUS_NOT_IN_REQUEST_MESSAGE, |
| 569 | "Data item name in name space was not requested in startRetrieval")); |
| 570 | } |
| 571 | } |
| 572 | |
| 573 | // Enforce access control. |
| 574 | // |
| 575 | // Access is granted if at least one of the profiles grants access. |
| 576 | // |
| 577 | // If an item is configured without any profiles, access is denied. |
| 578 | // |
| 579 | int accessControl = IIdentityCredentialStore::STATUS_NO_ACCESS_CONTROL_PROFILES; |
| 580 | for (auto id : accessControlProfileIds) { |
| 581 | auto search = profileIdToAccessCheckResult_.find(id); |
| 582 | if (search == profileIdToAccessCheckResult_.end()) { |
| 583 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 584 | IIdentityCredentialStore::STATUS_INVALID_DATA, |
| 585 | "Requested entry with unvalidated profile id")); |
| 586 | } |
| 587 | int accessControlForProfile = search->second; |
| 588 | if (accessControlForProfile == IIdentityCredentialStore::STATUS_OK) { |
| 589 | accessControl = IIdentityCredentialStore::STATUS_OK; |
| 590 | break; |
| 591 | } |
| 592 | accessControl = accessControlForProfile; |
| 593 | } |
| 594 | if (accessControl != IIdentityCredentialStore::STATUS_OK) { |
| 595 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 596 | int(accessControl), "Access control check failed")); |
| 597 | } |
| 598 | |
| 599 | entryAdditionalData_ = entryCreateAdditionalData(nameSpace, name, accessControlProfileIds); |
| 600 | |
| 601 | currentName_ = name; |
| 602 | entryRemainingBytes_ = entrySize; |
| 603 | entryValue_.resize(0); |
| 604 | |
| 605 | return ndk::ScopedAStatus::ok(); |
| 606 | } |
| 607 | |
| 608 | ndk::ScopedAStatus IdentityCredential::retrieveEntryValue(const vector<int8_t>& encryptedContentS, |
| 609 | vector<int8_t>* outContent) { |
| 610 | auto encryptedContent = byteStringToUnsigned(encryptedContentS); |
| 611 | |
| 612 | optional<vector<uint8_t>> content = |
| 613 | support::decryptAes128Gcm(storageKey_, encryptedContent, entryAdditionalData_); |
| 614 | if (!content) { |
| 615 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 616 | IIdentityCredentialStore::STATUS_INVALID_DATA, "Error decrypting data")); |
| 617 | } |
| 618 | |
| 619 | size_t chunkSize = content.value().size(); |
| 620 | |
| 621 | if (chunkSize > entryRemainingBytes_) { |
| 622 | LOG(ERROR) << "Retrieved chunk of size " << chunkSize |
| 623 | << " is bigger than remaining space of size " << entryRemainingBytes_; |
| 624 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 625 | IIdentityCredentialStore::STATUS_INVALID_DATA, |
| 626 | "Retrieved chunk is bigger than remaining space")); |
| 627 | } |
| 628 | |
| 629 | entryRemainingBytes_ -= chunkSize; |
| 630 | if (entryRemainingBytes_ > 0) { |
| 631 | if (chunkSize != IdentityCredentialStore::kGcmChunkSize) { |
| 632 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 633 | IIdentityCredentialStore::STATUS_INVALID_DATA, |
| 634 | "Retrieved non-final chunk of size which isn't kGcmChunkSize")); |
| 635 | } |
| 636 | } |
| 637 | |
| 638 | entryValue_.insert(entryValue_.end(), content.value().begin(), content.value().end()); |
| 639 | |
| 640 | if (entryRemainingBytes_ == 0) { |
| 641 | auto [entryValueItem, _, message] = cppbor::parse(entryValue_); |
| 642 | if (entryValueItem == nullptr) { |
| 643 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 644 | IIdentityCredentialStore::STATUS_INVALID_DATA, |
| 645 | "Retrieved data which is invalid CBOR")); |
| 646 | } |
| 647 | currentNameSpaceDeviceNameSpacesMap_.add(currentName_, std::move(entryValueItem)); |
| 648 | } |
| 649 | |
| 650 | *outContent = byteStringToSigned(content.value()); |
| 651 | return ndk::ScopedAStatus::ok(); |
| 652 | } |
| 653 | |
David Zeuthen | e35797f | 2020-02-27 14:25:54 -0500 | [diff] [blame] | 654 | ndk::ScopedAStatus IdentityCredential::finishRetrieval(vector<int8_t>* outMac, |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 655 | vector<int8_t>* outDeviceNameSpaces) { |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 656 | if (currentNameSpaceDeviceNameSpacesMap_.size() > 0) { |
| 657 | deviceNameSpacesMap_.add(currentNameSpace_, |
| 658 | std::move(currentNameSpaceDeviceNameSpacesMap_)); |
| 659 | } |
| 660 | vector<uint8_t> encodedDeviceNameSpaces = deviceNameSpacesMap_.encode(); |
| 661 | |
| 662 | // If there's no signing key or no sessionTranscript or no reader ephemeral |
| 663 | // public key, we return the empty MAC. |
| 664 | optional<vector<uint8_t>> mac; |
David Zeuthen | e35797f | 2020-02-27 14:25:54 -0500 | [diff] [blame] | 665 | if (signingKeyBlob_.size() > 0 && sessionTranscript_.size() > 0 && |
| 666 | readerPublicKey_.size() > 0) { |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 667 | cppbor::Array array; |
| 668 | array.add("DeviceAuthentication"); |
| 669 | array.add(sessionTranscriptItem_->clone()); |
| 670 | array.add(docType_); |
| 671 | array.add(cppbor::Semantic(24, encodedDeviceNameSpaces)); |
| 672 | vector<uint8_t> encodedDeviceAuthentication = array.encode(); |
| 673 | |
| 674 | vector<uint8_t> docTypeAsBlob(docType_.begin(), docType_.end()); |
| 675 | optional<vector<uint8_t>> signingKey = |
David Zeuthen | e35797f | 2020-02-27 14:25:54 -0500 | [diff] [blame] | 676 | support::decryptAes128Gcm(storageKey_, signingKeyBlob_, docTypeAsBlob); |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 677 | if (!signingKey) { |
| 678 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 679 | IIdentityCredentialStore::STATUS_INVALID_DATA, |
| 680 | "Error decrypting signingKeyBlob")); |
| 681 | } |
| 682 | |
| 683 | optional<vector<uint8_t>> sharedSecret = |
| 684 | support::ecdh(readerPublicKey_, signingKey.value()); |
| 685 | if (!sharedSecret) { |
| 686 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 687 | IIdentityCredentialStore::STATUS_FAILED, "Error doing ECDH")); |
| 688 | } |
| 689 | |
| 690 | vector<uint8_t> salt = {0x00}; |
| 691 | vector<uint8_t> info = {}; |
| 692 | optional<vector<uint8_t>> derivedKey = support::hkdf(sharedSecret.value(), salt, info, 32); |
| 693 | if (!derivedKey) { |
| 694 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 695 | IIdentityCredentialStore::STATUS_FAILED, |
| 696 | "Error deriving key from shared secret")); |
| 697 | } |
| 698 | |
| 699 | mac = support::coseMac0(derivedKey.value(), {}, // payload |
| 700 | encodedDeviceAuthentication); // additionalData |
| 701 | if (!mac) { |
| 702 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 703 | IIdentityCredentialStore::STATUS_FAILED, "Error MACing data")); |
| 704 | } |
| 705 | } |
| 706 | |
| 707 | *outMac = byteStringToSigned(mac.value_or(vector<uint8_t>({}))); |
| 708 | *outDeviceNameSpaces = byteStringToSigned(encodedDeviceNameSpaces); |
| 709 | return ndk::ScopedAStatus::ok(); |
| 710 | } |
| 711 | |
| 712 | ndk::ScopedAStatus IdentityCredential::generateSigningKeyPair( |
| 713 | vector<int8_t>* outSigningKeyBlob, Certificate* outSigningKeyCertificate) { |
| 714 | string serialDecimal = "0"; // TODO: set serial to something unique |
| 715 | string issuer = "Android Open Source Project"; |
| 716 | string subject = "Android IdentityCredential Reference Implementation"; |
| 717 | time_t validityNotBefore = time(nullptr); |
| 718 | time_t validityNotAfter = validityNotBefore + 365 * 24 * 3600; |
| 719 | |
| 720 | optional<vector<uint8_t>> signingKeyPKCS8 = support::createEcKeyPair(); |
| 721 | if (!signingKeyPKCS8) { |
| 722 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 723 | IIdentityCredentialStore::STATUS_FAILED, "Error creating signingKey")); |
| 724 | } |
| 725 | |
| 726 | optional<vector<uint8_t>> signingPublicKey = |
| 727 | support::ecKeyPairGetPublicKey(signingKeyPKCS8.value()); |
| 728 | if (!signingPublicKey) { |
| 729 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 730 | IIdentityCredentialStore::STATUS_FAILED, |
| 731 | "Error getting public part of signingKey")); |
| 732 | } |
| 733 | |
| 734 | optional<vector<uint8_t>> signingKey = support::ecKeyPairGetPrivateKey(signingKeyPKCS8.value()); |
| 735 | if (!signingKey) { |
| 736 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 737 | IIdentityCredentialStore::STATUS_FAILED, |
| 738 | "Error getting private part of signingKey")); |
| 739 | } |
| 740 | |
| 741 | optional<vector<uint8_t>> certificate = support::ecPublicKeyGenerateCertificate( |
| 742 | signingPublicKey.value(), credentialPrivKey_, serialDecimal, issuer, subject, |
| 743 | validityNotBefore, validityNotAfter); |
| 744 | if (!certificate) { |
| 745 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 746 | IIdentityCredentialStore::STATUS_FAILED, "Error creating signingKey")); |
| 747 | } |
| 748 | |
| 749 | optional<vector<uint8_t>> nonce = support::getRandom(12); |
| 750 | if (!nonce) { |
| 751 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 752 | IIdentityCredentialStore::STATUS_FAILED, "Error getting random")); |
| 753 | } |
| 754 | vector<uint8_t> docTypeAsBlob(docType_.begin(), docType_.end()); |
| 755 | optional<vector<uint8_t>> encryptedSigningKey = support::encryptAes128Gcm( |
| 756 | storageKey_, nonce.value(), signingKey.value(), docTypeAsBlob); |
| 757 | if (!encryptedSigningKey) { |
| 758 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 759 | IIdentityCredentialStore::STATUS_FAILED, "Error encrypting signingKey")); |
| 760 | } |
| 761 | *outSigningKeyBlob = byteStringToSigned(encryptedSigningKey.value()); |
| 762 | *outSigningKeyCertificate = Certificate(); |
| 763 | outSigningKeyCertificate->encodedCertificate = byteStringToSigned(certificate.value()); |
| 764 | return ndk::ScopedAStatus::ok(); |
| 765 | } |
| 766 | |
| 767 | } // namespace aidl::android::hardware::identity |