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> |
David Zeuthen | 28edb10 | 2020-04-28 18:54:55 -0400 | [diff] [blame] | 28 | #include <android-base/stringprintf.h> |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 29 | |
| 30 | #include <cppbor.h> |
| 31 | #include <cppbor_parse.h> |
| 32 | |
| 33 | namespace aidl::android::hardware::identity { |
| 34 | |
| 35 | using ::aidl::android::hardware::keymaster::Timestamp; |
David Zeuthen | 28edb10 | 2020-04-28 18:54:55 -0400 | [diff] [blame] | 36 | using ::android::base::StringPrintf; |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 37 | using ::std::optional; |
| 38 | |
| 39 | using namespace ::android::hardware::identity; |
| 40 | |
| 41 | int IdentityCredential::initialize() { |
David Zeuthen | 2e4533e | 2020-06-20 17:04:41 -0400 | [diff] [blame^] | 42 | if (credentialData_.size() == 0) { |
| 43 | LOG(ERROR) << "CredentialData is empty"; |
| 44 | return IIdentityCredentialStore::STATUS_INVALID_DATA; |
| 45 | } |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 46 | auto [item, _, message] = cppbor::parse(credentialData_); |
| 47 | if (item == nullptr) { |
| 48 | LOG(ERROR) << "CredentialData is not valid CBOR: " << message; |
| 49 | return IIdentityCredentialStore::STATUS_INVALID_DATA; |
| 50 | } |
| 51 | |
| 52 | const cppbor::Array* arrayItem = item->asArray(); |
| 53 | if (arrayItem == nullptr || arrayItem->size() != 3) { |
| 54 | LOG(ERROR) << "CredentialData is not an array with three elements"; |
| 55 | return IIdentityCredentialStore::STATUS_INVALID_DATA; |
| 56 | } |
| 57 | |
| 58 | const cppbor::Tstr* docTypeItem = (*arrayItem)[0]->asTstr(); |
| 59 | const cppbor::Bool* testCredentialItem = |
| 60 | ((*arrayItem)[1]->asSimple() != nullptr ? ((*arrayItem)[1]->asSimple()->asBool()) |
| 61 | : nullptr); |
| 62 | const cppbor::Bstr* encryptedCredentialKeysItem = (*arrayItem)[2]->asBstr(); |
| 63 | if (docTypeItem == nullptr || testCredentialItem == nullptr || |
| 64 | encryptedCredentialKeysItem == nullptr) { |
| 65 | LOG(ERROR) << "CredentialData unexpected item types"; |
| 66 | return IIdentityCredentialStore::STATUS_INVALID_DATA; |
| 67 | } |
| 68 | |
| 69 | docType_ = docTypeItem->value(); |
| 70 | testCredential_ = testCredentialItem->value(); |
| 71 | |
| 72 | vector<uint8_t> hardwareBoundKey; |
| 73 | if (testCredential_) { |
| 74 | hardwareBoundKey = support::getTestHardwareBoundKey(); |
| 75 | } else { |
| 76 | hardwareBoundKey = getHardwareBoundKey(); |
| 77 | } |
| 78 | |
| 79 | const vector<uint8_t>& encryptedCredentialKeys = encryptedCredentialKeysItem->value(); |
| 80 | const vector<uint8_t> docTypeVec(docType_.begin(), docType_.end()); |
| 81 | optional<vector<uint8_t>> decryptedCredentialKeys = |
| 82 | support::decryptAes128Gcm(hardwareBoundKey, encryptedCredentialKeys, docTypeVec); |
| 83 | if (!decryptedCredentialKeys) { |
| 84 | LOG(ERROR) << "Error decrypting CredentialKeys"; |
| 85 | return IIdentityCredentialStore::STATUS_INVALID_DATA; |
| 86 | } |
| 87 | |
| 88 | auto [dckItem, dckPos, dckMessage] = cppbor::parse(decryptedCredentialKeys.value()); |
| 89 | if (dckItem == nullptr) { |
| 90 | LOG(ERROR) << "Decrypted CredentialKeys is not valid CBOR: " << dckMessage; |
| 91 | return IIdentityCredentialStore::STATUS_INVALID_DATA; |
| 92 | } |
| 93 | const cppbor::Array* dckArrayItem = dckItem->asArray(); |
| 94 | if (dckArrayItem == nullptr || dckArrayItem->size() != 2) { |
| 95 | LOG(ERROR) << "Decrypted CredentialKeys is not an array with two elements"; |
| 96 | return IIdentityCredentialStore::STATUS_INVALID_DATA; |
| 97 | } |
| 98 | const cppbor::Bstr* storageKeyItem = (*dckArrayItem)[0]->asBstr(); |
| 99 | const cppbor::Bstr* credentialPrivKeyItem = (*dckArrayItem)[1]->asBstr(); |
| 100 | if (storageKeyItem == nullptr || credentialPrivKeyItem == nullptr) { |
| 101 | LOG(ERROR) << "CredentialKeys unexpected item types"; |
| 102 | return IIdentityCredentialStore::STATUS_INVALID_DATA; |
| 103 | } |
| 104 | storageKey_ = storageKeyItem->value(); |
| 105 | credentialPrivKey_ = credentialPrivKeyItem->value(); |
| 106 | |
| 107 | return IIdentityCredentialStore::STATUS_OK; |
| 108 | } |
| 109 | |
| 110 | ndk::ScopedAStatus IdentityCredential::deleteCredential( |
Jooyung Han | 17be89b | 2020-02-21 21:17:06 +0900 | [diff] [blame] | 111 | vector<uint8_t>* outProofOfDeletionSignature) { |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 112 | cppbor::Array array = {"ProofOfDeletion", docType_, testCredential_}; |
| 113 | vector<uint8_t> proofOfDeletion = array.encode(); |
| 114 | |
| 115 | optional<vector<uint8_t>> signature = support::coseSignEcDsa(credentialPrivKey_, |
| 116 | proofOfDeletion, // payload |
| 117 | {}, // additionalData |
| 118 | {}); // certificateChain |
| 119 | if (!signature) { |
| 120 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 121 | IIdentityCredentialStore::STATUS_FAILED, "Error signing data")); |
| 122 | } |
| 123 | |
Jooyung Han | 17be89b | 2020-02-21 21:17:06 +0900 | [diff] [blame] | 124 | *outProofOfDeletionSignature = signature.value(); |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 125 | return ndk::ScopedAStatus::ok(); |
| 126 | } |
| 127 | |
Jooyung Han | 17be89b | 2020-02-21 21:17:06 +0900 | [diff] [blame] | 128 | ndk::ScopedAStatus IdentityCredential::createEphemeralKeyPair(vector<uint8_t>* outKeyPair) { |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 129 | optional<vector<uint8_t>> kp = support::createEcKeyPair(); |
| 130 | if (!kp) { |
| 131 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 132 | IIdentityCredentialStore::STATUS_FAILED, "Error creating ephemeral key pair")); |
| 133 | } |
| 134 | |
| 135 | // Stash public key of this key-pair for later check in startRetrieval(). |
| 136 | optional<vector<uint8_t>> publicKey = support::ecKeyPairGetPublicKey(kp.value()); |
| 137 | if (!publicKey) { |
| 138 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 139 | IIdentityCredentialStore::STATUS_FAILED, |
| 140 | "Error getting public part of ephemeral key pair")); |
| 141 | } |
| 142 | ephemeralPublicKey_ = publicKey.value(); |
| 143 | |
Jooyung Han | 17be89b | 2020-02-21 21:17:06 +0900 | [diff] [blame] | 144 | *outKeyPair = kp.value(); |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 145 | return ndk::ScopedAStatus::ok(); |
| 146 | } |
| 147 | |
| 148 | ndk::ScopedAStatus IdentityCredential::setReaderEphemeralPublicKey( |
Jooyung Han | 17be89b | 2020-02-21 21:17:06 +0900 | [diff] [blame] | 149 | const vector<uint8_t>& publicKey) { |
| 150 | readerPublicKey_ = publicKey; |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 151 | return ndk::ScopedAStatus::ok(); |
| 152 | } |
| 153 | |
| 154 | ndk::ScopedAStatus IdentityCredential::createAuthChallenge(int64_t* outChallenge) { |
| 155 | uint64_t challenge = 0; |
| 156 | while (challenge == 0) { |
| 157 | optional<vector<uint8_t>> bytes = support::getRandom(8); |
| 158 | if (!bytes) { |
| 159 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 160 | IIdentityCredentialStore::STATUS_FAILED, |
| 161 | "Error getting random data for challenge")); |
| 162 | } |
| 163 | |
| 164 | challenge = 0; |
| 165 | for (size_t n = 0; n < bytes.value().size(); n++) { |
| 166 | challenge |= ((bytes.value())[n] << (n * 8)); |
| 167 | } |
| 168 | } |
| 169 | |
| 170 | *outChallenge = challenge; |
David Zeuthen | ef73951 | 2020-06-03 13:24:52 -0400 | [diff] [blame] | 171 | authChallenge_ = challenge; |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 172 | return ndk::ScopedAStatus::ok(); |
| 173 | } |
| 174 | |
| 175 | // TODO: this could be a lot faster if we did all the splitting and pubkey extraction |
| 176 | // ahead of time. |
| 177 | bool checkReaderAuthentication(const SecureAccessControlProfile& profile, |
| 178 | const vector<uint8_t>& readerCertificateChain) { |
Jooyung Han | 17be89b | 2020-02-21 21:17:06 +0900 | [diff] [blame] | 179 | optional<vector<uint8_t>> acpPubKey = |
| 180 | support::certificateChainGetTopMostKey(profile.readerCertificate.encodedCertificate); |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 181 | if (!acpPubKey) { |
| 182 | LOG(ERROR) << "Error extracting public key from readerCertificate in profile"; |
| 183 | return false; |
| 184 | } |
| 185 | |
| 186 | optional<vector<vector<uint8_t>>> certificatesInChain = |
| 187 | support::certificateChainSplit(readerCertificateChain); |
| 188 | if (!certificatesInChain) { |
| 189 | LOG(ERROR) << "Error splitting readerCertificateChain"; |
| 190 | return false; |
| 191 | } |
| 192 | for (const vector<uint8_t>& certInChain : certificatesInChain.value()) { |
| 193 | optional<vector<uint8_t>> certPubKey = support::certificateChainGetTopMostKey(certInChain); |
| 194 | if (!certPubKey) { |
| 195 | LOG(ERROR) |
| 196 | << "Error extracting public key from certificate in chain presented by reader"; |
| 197 | return false; |
| 198 | } |
| 199 | if (acpPubKey.value() == certPubKey.value()) { |
| 200 | return true; |
| 201 | } |
| 202 | } |
| 203 | return false; |
| 204 | } |
| 205 | |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 206 | bool checkUserAuthentication(const SecureAccessControlProfile& profile, |
David Zeuthen | a8ed82c | 2020-05-08 10:03:28 -0400 | [diff] [blame] | 207 | const VerificationToken& verificationToken, |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 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 | |
David Zeuthen | a8ed82c | 2020-05-08 10:03:28 -0400 | [diff] [blame] | 215 | if (verificationToken.timestamp.milliSeconds == 0) { |
| 216 | LOG(ERROR) << "VerificationToken is not set"; |
| 217 | return false; |
| 218 | } |
| 219 | if (authToken.timestamp.milliSeconds == 0) { |
| 220 | LOG(ERROR) << "AuthToken is not set"; |
| 221 | return false; |
| 222 | } |
| 223 | |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 224 | if (profile.timeoutMillis == 0) { |
| 225 | if (authToken.challenge == 0) { |
| 226 | LOG(ERROR) << "No challenge in authToken"; |
| 227 | return false; |
| 228 | } |
| 229 | |
| 230 | if (authToken.challenge != int64_t(authChallenge)) { |
David Zeuthen | ef73951 | 2020-06-03 13:24:52 -0400 | [diff] [blame] | 231 | LOG(ERROR) << "Challenge in authToken (" << uint64_t(authToken.challenge) << ") " |
| 232 | << "doesn't match the challenge we created (" << authChallenge << ")"; |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 233 | return false; |
| 234 | } |
| 235 | return true; |
| 236 | } |
| 237 | |
David Zeuthen | a8ed82c | 2020-05-08 10:03:28 -0400 | [diff] [blame] | 238 | // Timeout-based user auth follows. The verification token conveys what the |
| 239 | // time is right now in the environment which generated the auth token. This |
| 240 | // is what makes it possible to do timeout-based checks. |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 241 | // |
David Zeuthen | a8ed82c | 2020-05-08 10:03:28 -0400 | [diff] [blame] | 242 | const Timestamp now = verificationToken.timestamp; |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 243 | if (authToken.timestamp.milliSeconds > now.milliSeconds) { |
| 244 | LOG(ERROR) << "Timestamp in authToken (" << authToken.timestamp.milliSeconds |
| 245 | << ") is in the future (now: " << now.milliSeconds << ")"; |
| 246 | return false; |
| 247 | } |
| 248 | if (now.milliSeconds > authToken.timestamp.milliSeconds + profile.timeoutMillis) { |
| 249 | LOG(ERROR) << "Deadline for authToken (" << authToken.timestamp.milliSeconds << " + " |
| 250 | << profile.timeoutMillis << " = " |
| 251 | << (authToken.timestamp.milliSeconds + profile.timeoutMillis) |
| 252 | << ") is in the past (now: " << now.milliSeconds << ")"; |
| 253 | return false; |
| 254 | } |
| 255 | return true; |
| 256 | } |
| 257 | |
David Zeuthen | 28edb10 | 2020-04-28 18:54:55 -0400 | [diff] [blame] | 258 | ndk::ScopedAStatus IdentityCredential::setRequestedNamespaces( |
| 259 | const vector<RequestNamespace>& requestNamespaces) { |
| 260 | requestNamespaces_ = requestNamespaces; |
| 261 | return ndk::ScopedAStatus::ok(); |
| 262 | } |
| 263 | |
David Zeuthen | a8ed82c | 2020-05-08 10:03:28 -0400 | [diff] [blame] | 264 | ndk::ScopedAStatus IdentityCredential::setVerificationToken( |
| 265 | const VerificationToken& verificationToken) { |
| 266 | verificationToken_ = verificationToken; |
| 267 | return ndk::ScopedAStatus::ok(); |
| 268 | } |
| 269 | |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 270 | ndk::ScopedAStatus IdentityCredential::startRetrieval( |
| 271 | const vector<SecureAccessControlProfile>& accessControlProfiles, |
Jooyung Han | 17be89b | 2020-02-21 21:17:06 +0900 | [diff] [blame] | 272 | const HardwareAuthToken& authToken, const vector<uint8_t>& itemsRequest, |
| 273 | const vector<uint8_t>& signingKeyBlob, const vector<uint8_t>& sessionTranscript, |
| 274 | const vector<uint8_t>& readerSignature, const vector<int32_t>& requestCounts) { |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 275 | if (sessionTranscript.size() > 0) { |
| 276 | auto [item, _, message] = cppbor::parse(sessionTranscript); |
| 277 | if (item == nullptr) { |
| 278 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 279 | IIdentityCredentialStore::STATUS_INVALID_DATA, |
| 280 | "SessionTranscript contains invalid CBOR")); |
| 281 | } |
| 282 | sessionTranscriptItem_ = std::move(item); |
| 283 | } |
| 284 | if (numStartRetrievalCalls_ > 0) { |
| 285 | if (sessionTranscript_ != sessionTranscript) { |
| 286 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 287 | IIdentityCredentialStore::STATUS_SESSION_TRANSCRIPT_MISMATCH, |
| 288 | "Passed-in SessionTranscript doesn't match previously used SessionTranscript")); |
| 289 | } |
| 290 | } |
| 291 | sessionTranscript_ = sessionTranscript; |
| 292 | |
| 293 | // If there is a signature, validate that it was made with the top-most key in the |
| 294 | // certificate chain embedded in the COSE_Sign1 structure. |
| 295 | optional<vector<uint8_t>> readerCertificateChain; |
| 296 | if (readerSignature.size() > 0) { |
| 297 | readerCertificateChain = support::coseSignGetX5Chain(readerSignature); |
| 298 | if (!readerCertificateChain) { |
| 299 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 300 | IIdentityCredentialStore::STATUS_READER_SIGNATURE_CHECK_FAILED, |
| 301 | "Unable to get reader certificate chain from COSE_Sign1")); |
| 302 | } |
| 303 | |
| 304 | if (!support::certificateChainValidate(readerCertificateChain.value())) { |
| 305 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 306 | IIdentityCredentialStore::STATUS_READER_SIGNATURE_CHECK_FAILED, |
| 307 | "Error validating reader certificate chain")); |
| 308 | } |
| 309 | |
| 310 | optional<vector<uint8_t>> readerPublicKey = |
| 311 | support::certificateChainGetTopMostKey(readerCertificateChain.value()); |
| 312 | if (!readerPublicKey) { |
| 313 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 314 | IIdentityCredentialStore::STATUS_READER_SIGNATURE_CHECK_FAILED, |
| 315 | "Unable to get public key from reader certificate chain")); |
| 316 | } |
| 317 | |
| 318 | const vector<uint8_t>& itemsRequestBytes = itemsRequest; |
David Zeuthen | 2e4533e | 2020-06-20 17:04:41 -0400 | [diff] [blame^] | 319 | vector<uint8_t> encodedReaderAuthentication = |
| 320 | cppbor::Array() |
| 321 | .add("ReaderAuthentication") |
| 322 | .add(sessionTranscriptItem_->clone()) |
| 323 | .add(cppbor::Semantic(24, itemsRequestBytes)) |
| 324 | .encode(); |
| 325 | vector<uint8_t> encodedReaderAuthenticationBytes = |
| 326 | cppbor::Semantic(24, encodedReaderAuthentication).encode(); |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 327 | if (!support::coseCheckEcDsaSignature(readerSignature, |
David Zeuthen | 2e4533e | 2020-06-20 17:04:41 -0400 | [diff] [blame^] | 328 | encodedReaderAuthenticationBytes, // detached content |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 329 | readerPublicKey.value())) { |
| 330 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 331 | IIdentityCredentialStore::STATUS_READER_SIGNATURE_CHECK_FAILED, |
| 332 | "readerSignature check failed")); |
| 333 | } |
| 334 | } |
| 335 | |
| 336 | // Here's where we would validate the passed-in |authToken| to assure ourselves |
| 337 | // that it comes from the e.g. biometric hardware and wasn't made up by an attacker. |
| 338 | // |
| 339 | // However this involves calculating the MAC. However this requires access |
| 340 | // to the key needed to a pre-shared key which we don't have... |
| 341 | // |
| 342 | |
| 343 | // To prevent replay-attacks, we check that the public part of the ephemeral |
| 344 | // key we previously created, is present in the DeviceEngagement part of |
| 345 | // SessionTranscript as a COSE_Key, in uncompressed form. |
| 346 | // |
| 347 | // We do this by just searching for the X and Y coordinates. |
| 348 | if (sessionTranscript.size() > 0) { |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 349 | auto [getXYSuccess, ePubX, ePubY] = support::ecPublicKeyGetXandY(ephemeralPublicKey_); |
| 350 | if (!getXYSuccess) { |
| 351 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 352 | IIdentityCredentialStore::STATUS_EPHEMERAL_PUBLIC_KEY_NOT_FOUND, |
| 353 | "Error extracting X and Y from ePub")); |
| 354 | } |
| 355 | if (sessionTranscript.size() > 0 && |
David Zeuthen | ef73951 | 2020-06-03 13:24:52 -0400 | [diff] [blame] | 356 | !(memmem(sessionTranscript.data(), sessionTranscript.size(), ePubX.data(), |
| 357 | ePubX.size()) != nullptr && |
| 358 | memmem(sessionTranscript.data(), sessionTranscript.size(), ePubY.data(), |
| 359 | ePubY.size()) != nullptr)) { |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 360 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 361 | IIdentityCredentialStore::STATUS_EPHEMERAL_PUBLIC_KEY_NOT_FOUND, |
| 362 | "Did not find ephemeral public key's X and Y coordinates in " |
| 363 | "SessionTranscript (make sure leading zeroes are not used)")); |
| 364 | } |
| 365 | } |
| 366 | |
| 367 | // itemsRequest: If non-empty, contains request data that may be signed by the |
| 368 | // reader. The content can be defined in the way appropriate for the |
| 369 | // credential, but there are three requirements that must be met to work with |
| 370 | // this HAL: |
| 371 | if (itemsRequest.size() > 0) { |
| 372 | // 1. The content must be a CBOR-encoded structure. |
| 373 | auto [item, _, message] = cppbor::parse(itemsRequest); |
| 374 | if (item == nullptr) { |
| 375 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 376 | IIdentityCredentialStore::STATUS_INVALID_ITEMS_REQUEST_MESSAGE, |
| 377 | "Error decoding CBOR in itemsRequest")); |
| 378 | } |
| 379 | |
| 380 | // 2. The CBOR structure must be a map. |
| 381 | const cppbor::Map* map = item->asMap(); |
| 382 | if (map == nullptr) { |
| 383 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 384 | IIdentityCredentialStore::STATUS_INVALID_ITEMS_REQUEST_MESSAGE, |
| 385 | "itemsRequest is not a CBOR map")); |
| 386 | } |
| 387 | |
| 388 | // 3. The map must contain a key "nameSpaces" whose value contains a map, as described in |
| 389 | // the example below. |
| 390 | // |
| 391 | // NameSpaces = { |
| 392 | // + NameSpace => DataElements ; Requested data elements for each NameSpace |
| 393 | // } |
| 394 | // |
| 395 | // NameSpace = tstr |
| 396 | // |
| 397 | // DataElements = { |
| 398 | // + DataElement => IntentToRetain |
| 399 | // } |
| 400 | // |
| 401 | // DataElement = tstr |
| 402 | // IntentToRetain = bool |
| 403 | // |
| 404 | // Here's an example of an |itemsRequest| CBOR value satisfying above requirements 1. |
| 405 | // through 3.: |
| 406 | // |
| 407 | // { |
| 408 | // 'docType' : 'org.iso.18013-5.2019', |
| 409 | // 'nameSpaces' : { |
| 410 | // 'org.iso.18013-5.2019' : { |
| 411 | // 'Last name' : false, |
| 412 | // 'Birth date' : false, |
| 413 | // 'First name' : false, |
| 414 | // 'Home address' : true |
| 415 | // }, |
| 416 | // 'org.aamva.iso.18013-5.2019' : { |
| 417 | // 'Real Id' : false |
| 418 | // } |
| 419 | // } |
| 420 | // } |
| 421 | // |
| 422 | const cppbor::Map* nsMap = nullptr; |
| 423 | for (size_t n = 0; n < map->size(); n++) { |
| 424 | const auto& [keyItem, valueItem] = (*map)[n]; |
| 425 | if (keyItem->type() == cppbor::TSTR && keyItem->asTstr()->value() == "nameSpaces" && |
| 426 | valueItem->type() == cppbor::MAP) { |
| 427 | nsMap = valueItem->asMap(); |
| 428 | break; |
| 429 | } |
| 430 | } |
| 431 | if (nsMap == nullptr) { |
| 432 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 433 | IIdentityCredentialStore::STATUS_INVALID_ITEMS_REQUEST_MESSAGE, |
| 434 | "No nameSpaces map in top-most map")); |
| 435 | } |
| 436 | |
| 437 | for (size_t n = 0; n < nsMap->size(); n++) { |
| 438 | auto [nsKeyItem, nsValueItem] = (*nsMap)[n]; |
| 439 | const cppbor::Tstr* nsKey = nsKeyItem->asTstr(); |
| 440 | const cppbor::Map* nsInnerMap = nsValueItem->asMap(); |
| 441 | if (nsKey == nullptr || nsInnerMap == nullptr) { |
| 442 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 443 | IIdentityCredentialStore::STATUS_INVALID_ITEMS_REQUEST_MESSAGE, |
| 444 | "Type mismatch in nameSpaces map")); |
| 445 | } |
| 446 | string requestedNamespace = nsKey->value(); |
David Zeuthen | 28edb10 | 2020-04-28 18:54:55 -0400 | [diff] [blame] | 447 | set<string> requestedKeys; |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 448 | for (size_t m = 0; m < nsInnerMap->size(); m++) { |
| 449 | const auto& [innerMapKeyItem, innerMapValueItem] = (*nsInnerMap)[m]; |
| 450 | const cppbor::Tstr* nameItem = innerMapKeyItem->asTstr(); |
| 451 | const cppbor::Simple* simple = innerMapValueItem->asSimple(); |
| 452 | const cppbor::Bool* intentToRetainItem = |
| 453 | (simple != nullptr) ? simple->asBool() : nullptr; |
| 454 | if (nameItem == nullptr || intentToRetainItem == nullptr) { |
| 455 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 456 | IIdentityCredentialStore::STATUS_INVALID_ITEMS_REQUEST_MESSAGE, |
| 457 | "Type mismatch in value in nameSpaces map")); |
| 458 | } |
David Zeuthen | 28edb10 | 2020-04-28 18:54:55 -0400 | [diff] [blame] | 459 | requestedKeys.insert(nameItem->value()); |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 460 | } |
| 461 | requestedNameSpacesAndNames_[requestedNamespace] = requestedKeys; |
| 462 | } |
| 463 | } |
| 464 | |
David Zeuthen | 28edb10 | 2020-04-28 18:54:55 -0400 | [diff] [blame] | 465 | // Validate all the access control profiles in the requestData. |
David Zeuthen | ef73951 | 2020-06-03 13:24:52 -0400 | [diff] [blame] | 466 | bool haveAuthToken = (authToken.timestamp.milliSeconds != int64_t(0)); |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 467 | for (const auto& profile : accessControlProfiles) { |
| 468 | if (!secureAccessControlProfileCheckMac(profile, storageKey_)) { |
David Zeuthen | ef73951 | 2020-06-03 13:24:52 -0400 | [diff] [blame] | 469 | LOG(ERROR) << "Error checking MAC for profile"; |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 470 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 471 | IIdentityCredentialStore::STATUS_INVALID_DATA, |
| 472 | "Error checking MAC for profile")); |
| 473 | } |
| 474 | int accessControlCheck = IIdentityCredentialStore::STATUS_OK; |
| 475 | if (profile.userAuthenticationRequired) { |
David Zeuthen | a8ed82c | 2020-05-08 10:03:28 -0400 | [diff] [blame] | 476 | if (!haveAuthToken || |
| 477 | !checkUserAuthentication(profile, verificationToken_, authToken, authChallenge_)) { |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 478 | accessControlCheck = IIdentityCredentialStore::STATUS_USER_AUTHENTICATION_FAILED; |
| 479 | } |
| 480 | } else if (profile.readerCertificate.encodedCertificate.size() > 0) { |
| 481 | if (!readerCertificateChain || |
| 482 | !checkReaderAuthentication(profile, readerCertificateChain.value())) { |
| 483 | accessControlCheck = IIdentityCredentialStore::STATUS_READER_AUTHENTICATION_FAILED; |
| 484 | } |
| 485 | } |
| 486 | profileIdToAccessCheckResult_[profile.id] = accessControlCheck; |
| 487 | } |
| 488 | |
| 489 | deviceNameSpacesMap_ = cppbor::Map(); |
| 490 | currentNameSpaceDeviceNameSpacesMap_ = cppbor::Map(); |
| 491 | |
| 492 | requestCountsRemaining_ = requestCounts; |
| 493 | currentNameSpace_ = ""; |
| 494 | |
| 495 | itemsRequest_ = itemsRequest; |
Jooyung Han | 17be89b | 2020-02-21 21:17:06 +0900 | [diff] [blame] | 496 | signingKeyBlob_ = signingKeyBlob; |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 497 | |
David Zeuthen | 28edb10 | 2020-04-28 18:54:55 -0400 | [diff] [blame] | 498 | // Finally, calculate the size of DeviceNameSpaces. We need to know it ahead of time. |
| 499 | expectedDeviceNameSpacesSize_ = calcDeviceNameSpacesSize(); |
| 500 | |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 501 | numStartRetrievalCalls_ += 1; |
| 502 | return ndk::ScopedAStatus::ok(); |
| 503 | } |
| 504 | |
David Zeuthen | 28edb10 | 2020-04-28 18:54:55 -0400 | [diff] [blame] | 505 | size_t cborNumBytesForLength(size_t length) { |
| 506 | if (length < 24) { |
| 507 | return 0; |
| 508 | } else if (length <= 0xff) { |
| 509 | return 1; |
| 510 | } else if (length <= 0xffff) { |
| 511 | return 2; |
| 512 | } else if (length <= 0xffffffff) { |
| 513 | return 4; |
| 514 | } |
| 515 | return 8; |
| 516 | } |
| 517 | |
| 518 | size_t cborNumBytesForTstr(const string& value) { |
| 519 | return 1 + cborNumBytesForLength(value.size()) + value.size(); |
| 520 | } |
| 521 | |
| 522 | size_t IdentityCredential::calcDeviceNameSpacesSize() { |
| 523 | /* |
| 524 | * This is how DeviceNameSpaces is defined: |
| 525 | * |
| 526 | * DeviceNameSpaces = { |
| 527 | * * NameSpace => DeviceSignedItems |
| 528 | * } |
| 529 | * DeviceSignedItems = { |
| 530 | * + DataItemName => DataItemValue |
| 531 | * } |
| 532 | * |
| 533 | * Namespace = tstr |
| 534 | * DataItemName = tstr |
| 535 | * DataItemValue = any |
| 536 | * |
| 537 | * This function will calculate its length using knowledge of how CBOR is |
| 538 | * encoded. |
| 539 | */ |
| 540 | size_t ret = 0; |
| 541 | size_t numNamespacesWithValues = 0; |
| 542 | for (const RequestNamespace& rns : requestNamespaces_) { |
| 543 | vector<RequestDataItem> itemsToInclude; |
| 544 | |
| 545 | for (const RequestDataItem& rdi : rns.items) { |
| 546 | // If we have a CBOR request message, skip if item isn't in it |
| 547 | if (itemsRequest_.size() > 0) { |
| 548 | const auto& it = requestedNameSpacesAndNames_.find(rns.namespaceName); |
| 549 | if (it == requestedNameSpacesAndNames_.end()) { |
| 550 | continue; |
| 551 | } |
| 552 | const set<string>& dataItemNames = it->second; |
| 553 | if (dataItemNames.find(rdi.name) == dataItemNames.end()) { |
| 554 | continue; |
| 555 | } |
| 556 | } |
| 557 | |
| 558 | // Access is granted if at least one of the profiles grants access. |
| 559 | // |
| 560 | // If an item is configured without any profiles, access is denied. |
| 561 | // |
| 562 | bool authorized = false; |
| 563 | for (auto id : rdi.accessControlProfileIds) { |
| 564 | auto it = profileIdToAccessCheckResult_.find(id); |
| 565 | if (it != profileIdToAccessCheckResult_.end()) { |
| 566 | int accessControlForProfile = it->second; |
| 567 | if (accessControlForProfile == IIdentityCredentialStore::STATUS_OK) { |
| 568 | authorized = true; |
| 569 | break; |
| 570 | } |
| 571 | } |
| 572 | } |
| 573 | if (!authorized) { |
| 574 | continue; |
| 575 | } |
| 576 | |
| 577 | itemsToInclude.push_back(rdi); |
| 578 | } |
| 579 | |
| 580 | // If no entries are to be in the namespace, we don't include it... |
| 581 | if (itemsToInclude.size() == 0) { |
| 582 | continue; |
| 583 | } |
| 584 | |
| 585 | // Key: NameSpace |
| 586 | ret += cborNumBytesForTstr(rns.namespaceName); |
| 587 | |
| 588 | // Value: Open the DeviceSignedItems map |
| 589 | ret += 1 + cborNumBytesForLength(itemsToInclude.size()); |
| 590 | |
| 591 | for (const RequestDataItem& item : itemsToInclude) { |
| 592 | // Key: DataItemName |
| 593 | ret += cborNumBytesForTstr(item.name); |
| 594 | |
| 595 | // Value: DataItemValue - entryData.size is the length of serialized CBOR so we use |
| 596 | // that. |
| 597 | ret += item.size; |
| 598 | } |
| 599 | |
| 600 | numNamespacesWithValues++; |
| 601 | } |
| 602 | |
| 603 | // Now that we now the nunber of namespaces with values, we know how many |
| 604 | // bytes the DeviceNamespaces map in the beginning is going to take up. |
| 605 | ret += 1 + cborNumBytesForLength(numNamespacesWithValues); |
| 606 | |
| 607 | return ret; |
| 608 | } |
| 609 | |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 610 | ndk::ScopedAStatus IdentityCredential::startRetrieveEntryValue( |
| 611 | const string& nameSpace, const string& name, int32_t entrySize, |
| 612 | const vector<int32_t>& accessControlProfileIds) { |
| 613 | if (name.empty()) { |
| 614 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 615 | IIdentityCredentialStore::STATUS_INVALID_DATA, "Name cannot be empty")); |
| 616 | } |
| 617 | if (nameSpace.empty()) { |
| 618 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 619 | IIdentityCredentialStore::STATUS_INVALID_DATA, "Name space cannot be empty")); |
| 620 | } |
| 621 | |
| 622 | if (requestCountsRemaining_.size() == 0) { |
| 623 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 624 | IIdentityCredentialStore::STATUS_INVALID_DATA, |
| 625 | "No more name spaces left to go through")); |
| 626 | } |
| 627 | |
| 628 | if (currentNameSpace_ == "") { |
| 629 | // First call. |
| 630 | currentNameSpace_ = nameSpace; |
| 631 | } |
| 632 | |
| 633 | if (nameSpace == currentNameSpace_) { |
| 634 | // Same namespace. |
| 635 | if (requestCountsRemaining_[0] == 0) { |
| 636 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 637 | IIdentityCredentialStore::STATUS_INVALID_DATA, |
| 638 | "No more entries to be retrieved in current name space")); |
| 639 | } |
| 640 | requestCountsRemaining_[0] -= 1; |
| 641 | } else { |
| 642 | // New namespace. |
| 643 | if (requestCountsRemaining_[0] != 0) { |
| 644 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 645 | IIdentityCredentialStore::STATUS_INVALID_DATA, |
| 646 | "Moved to new name space but one or more entries need to be retrieved " |
| 647 | "in current name space")); |
| 648 | } |
| 649 | if (currentNameSpaceDeviceNameSpacesMap_.size() > 0) { |
| 650 | deviceNameSpacesMap_.add(currentNameSpace_, |
| 651 | std::move(currentNameSpaceDeviceNameSpacesMap_)); |
| 652 | } |
| 653 | currentNameSpaceDeviceNameSpacesMap_ = cppbor::Map(); |
| 654 | |
| 655 | requestCountsRemaining_.erase(requestCountsRemaining_.begin()); |
| 656 | currentNameSpace_ = nameSpace; |
| 657 | } |
| 658 | |
| 659 | // It's permissible to have an empty itemsRequest... but if non-empty you can |
| 660 | // only request what was specified in said itemsRequest. Enforce that. |
| 661 | if (itemsRequest_.size() > 0) { |
| 662 | const auto& it = requestedNameSpacesAndNames_.find(nameSpace); |
| 663 | if (it == requestedNameSpacesAndNames_.end()) { |
| 664 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 665 | IIdentityCredentialStore::STATUS_NOT_IN_REQUEST_MESSAGE, |
| 666 | "Name space was not requested in startRetrieval")); |
| 667 | } |
David Zeuthen | 28edb10 | 2020-04-28 18:54:55 -0400 | [diff] [blame] | 668 | const set<string>& dataItemNames = it->second; |
| 669 | if (dataItemNames.find(name) == dataItemNames.end()) { |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 670 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 671 | IIdentityCredentialStore::STATUS_NOT_IN_REQUEST_MESSAGE, |
| 672 | "Data item name in name space was not requested in startRetrieval")); |
| 673 | } |
| 674 | } |
| 675 | |
| 676 | // Enforce access control. |
| 677 | // |
| 678 | // Access is granted if at least one of the profiles grants access. |
| 679 | // |
| 680 | // If an item is configured without any profiles, access is denied. |
| 681 | // |
| 682 | int accessControl = IIdentityCredentialStore::STATUS_NO_ACCESS_CONTROL_PROFILES; |
| 683 | for (auto id : accessControlProfileIds) { |
| 684 | auto search = profileIdToAccessCheckResult_.find(id); |
| 685 | if (search == profileIdToAccessCheckResult_.end()) { |
| 686 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 687 | IIdentityCredentialStore::STATUS_INVALID_DATA, |
| 688 | "Requested entry with unvalidated profile id")); |
| 689 | } |
| 690 | int accessControlForProfile = search->second; |
| 691 | if (accessControlForProfile == IIdentityCredentialStore::STATUS_OK) { |
| 692 | accessControl = IIdentityCredentialStore::STATUS_OK; |
| 693 | break; |
| 694 | } |
| 695 | accessControl = accessControlForProfile; |
| 696 | } |
| 697 | if (accessControl != IIdentityCredentialStore::STATUS_OK) { |
| 698 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 699 | int(accessControl), "Access control check failed")); |
| 700 | } |
| 701 | |
| 702 | entryAdditionalData_ = entryCreateAdditionalData(nameSpace, name, accessControlProfileIds); |
| 703 | |
| 704 | currentName_ = name; |
| 705 | entryRemainingBytes_ = entrySize; |
| 706 | entryValue_.resize(0); |
| 707 | |
| 708 | return ndk::ScopedAStatus::ok(); |
| 709 | } |
| 710 | |
Jooyung Han | 17be89b | 2020-02-21 21:17:06 +0900 | [diff] [blame] | 711 | ndk::ScopedAStatus IdentityCredential::retrieveEntryValue(const vector<uint8_t>& encryptedContent, |
| 712 | vector<uint8_t>* outContent) { |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 713 | optional<vector<uint8_t>> content = |
| 714 | support::decryptAes128Gcm(storageKey_, encryptedContent, entryAdditionalData_); |
| 715 | if (!content) { |
| 716 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 717 | IIdentityCredentialStore::STATUS_INVALID_DATA, "Error decrypting data")); |
| 718 | } |
| 719 | |
| 720 | size_t chunkSize = content.value().size(); |
| 721 | |
| 722 | if (chunkSize > entryRemainingBytes_) { |
| 723 | LOG(ERROR) << "Retrieved chunk of size " << chunkSize |
| 724 | << " is bigger than remaining space of size " << entryRemainingBytes_; |
| 725 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 726 | IIdentityCredentialStore::STATUS_INVALID_DATA, |
| 727 | "Retrieved chunk is bigger than remaining space")); |
| 728 | } |
| 729 | |
| 730 | entryRemainingBytes_ -= chunkSize; |
| 731 | if (entryRemainingBytes_ > 0) { |
| 732 | if (chunkSize != IdentityCredentialStore::kGcmChunkSize) { |
| 733 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 734 | IIdentityCredentialStore::STATUS_INVALID_DATA, |
| 735 | "Retrieved non-final chunk of size which isn't kGcmChunkSize")); |
| 736 | } |
| 737 | } |
| 738 | |
| 739 | entryValue_.insert(entryValue_.end(), content.value().begin(), content.value().end()); |
| 740 | |
| 741 | if (entryRemainingBytes_ == 0) { |
| 742 | auto [entryValueItem, _, message] = cppbor::parse(entryValue_); |
| 743 | if (entryValueItem == nullptr) { |
| 744 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 745 | IIdentityCredentialStore::STATUS_INVALID_DATA, |
| 746 | "Retrieved data which is invalid CBOR")); |
| 747 | } |
| 748 | currentNameSpaceDeviceNameSpacesMap_.add(currentName_, std::move(entryValueItem)); |
| 749 | } |
| 750 | |
Jooyung Han | 17be89b | 2020-02-21 21:17:06 +0900 | [diff] [blame] | 751 | *outContent = content.value(); |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 752 | return ndk::ScopedAStatus::ok(); |
| 753 | } |
| 754 | |
Jooyung Han | 17be89b | 2020-02-21 21:17:06 +0900 | [diff] [blame] | 755 | ndk::ScopedAStatus IdentityCredential::finishRetrieval(vector<uint8_t>* outMac, |
| 756 | vector<uint8_t>* outDeviceNameSpaces) { |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 757 | if (currentNameSpaceDeviceNameSpacesMap_.size() > 0) { |
| 758 | deviceNameSpacesMap_.add(currentNameSpace_, |
| 759 | std::move(currentNameSpaceDeviceNameSpacesMap_)); |
| 760 | } |
| 761 | vector<uint8_t> encodedDeviceNameSpaces = deviceNameSpacesMap_.encode(); |
| 762 | |
David Zeuthen | 28edb10 | 2020-04-28 18:54:55 -0400 | [diff] [blame] | 763 | if (encodedDeviceNameSpaces.size() != expectedDeviceNameSpacesSize_) { |
| 764 | LOG(ERROR) << "encodedDeviceNameSpaces is " << encodedDeviceNameSpaces.size() << " bytes, " |
| 765 | << "was expecting " << expectedDeviceNameSpacesSize_; |
| 766 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 767 | IIdentityCredentialStore::STATUS_INVALID_DATA, |
| 768 | StringPrintf( |
| 769 | "Unexpected CBOR size %zd for encodedDeviceNameSpaces, was expecting %zd", |
| 770 | encodedDeviceNameSpaces.size(), expectedDeviceNameSpacesSize_) |
| 771 | .c_str())); |
| 772 | } |
| 773 | |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 774 | // If there's no signing key or no sessionTranscript or no reader ephemeral |
| 775 | // public key, we return the empty MAC. |
| 776 | optional<vector<uint8_t>> mac; |
David Zeuthen | e35797f | 2020-02-27 14:25:54 -0500 | [diff] [blame] | 777 | if (signingKeyBlob_.size() > 0 && sessionTranscript_.size() > 0 && |
| 778 | readerPublicKey_.size() > 0) { |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 779 | cppbor::Array array; |
| 780 | array.add("DeviceAuthentication"); |
| 781 | array.add(sessionTranscriptItem_->clone()); |
| 782 | array.add(docType_); |
| 783 | array.add(cppbor::Semantic(24, encodedDeviceNameSpaces)); |
David Zeuthen | 2e4533e | 2020-06-20 17:04:41 -0400 | [diff] [blame^] | 784 | vector<uint8_t> deviceAuthenticationBytes = cppbor::Semantic(24, array.encode()).encode(); |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 785 | |
| 786 | vector<uint8_t> docTypeAsBlob(docType_.begin(), docType_.end()); |
| 787 | optional<vector<uint8_t>> signingKey = |
David Zeuthen | e35797f | 2020-02-27 14:25:54 -0500 | [diff] [blame] | 788 | support::decryptAes128Gcm(storageKey_, signingKeyBlob_, docTypeAsBlob); |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 789 | if (!signingKey) { |
| 790 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 791 | IIdentityCredentialStore::STATUS_INVALID_DATA, |
| 792 | "Error decrypting signingKeyBlob")); |
| 793 | } |
| 794 | |
| 795 | optional<vector<uint8_t>> sharedSecret = |
| 796 | support::ecdh(readerPublicKey_, signingKey.value()); |
| 797 | if (!sharedSecret) { |
| 798 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 799 | IIdentityCredentialStore::STATUS_FAILED, "Error doing ECDH")); |
| 800 | } |
| 801 | |
David Zeuthen | 2e4533e | 2020-06-20 17:04:41 -0400 | [diff] [blame^] | 802 | // Mix-in SessionTranscriptBytes |
| 803 | vector<uint8_t> sessionTranscriptBytes = cppbor::Semantic(24, sessionTranscript_).encode(); |
| 804 | vector<uint8_t> sharedSecretWithSessionTranscriptBytes = sharedSecret.value(); |
| 805 | std::copy(sessionTranscriptBytes.begin(), sessionTranscriptBytes.end(), |
| 806 | std::back_inserter(sharedSecretWithSessionTranscriptBytes)); |
| 807 | |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 808 | vector<uint8_t> salt = {0x00}; |
| 809 | vector<uint8_t> info = {}; |
David Zeuthen | 2e4533e | 2020-06-20 17:04:41 -0400 | [diff] [blame^] | 810 | optional<vector<uint8_t>> derivedKey = |
| 811 | support::hkdf(sharedSecretWithSessionTranscriptBytes, salt, info, 32); |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 812 | if (!derivedKey) { |
| 813 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 814 | IIdentityCredentialStore::STATUS_FAILED, |
| 815 | "Error deriving key from shared secret")); |
| 816 | } |
| 817 | |
David Zeuthen | 2e4533e | 2020-06-20 17:04:41 -0400 | [diff] [blame^] | 818 | mac = support::coseMac0(derivedKey.value(), {}, // payload |
| 819 | deviceAuthenticationBytes); // detached content |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 820 | if (!mac) { |
| 821 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 822 | IIdentityCredentialStore::STATUS_FAILED, "Error MACing data")); |
| 823 | } |
| 824 | } |
| 825 | |
Jooyung Han | 17be89b | 2020-02-21 21:17:06 +0900 | [diff] [blame] | 826 | *outMac = mac.value_or(vector<uint8_t>({})); |
| 827 | *outDeviceNameSpaces = encodedDeviceNameSpaces; |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 828 | return ndk::ScopedAStatus::ok(); |
| 829 | } |
| 830 | |
| 831 | ndk::ScopedAStatus IdentityCredential::generateSigningKeyPair( |
Jooyung Han | 17be89b | 2020-02-21 21:17:06 +0900 | [diff] [blame] | 832 | vector<uint8_t>* outSigningKeyBlob, Certificate* outSigningKeyCertificate) { |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 833 | string serialDecimal = "0"; // TODO: set serial to something unique |
| 834 | string issuer = "Android Open Source Project"; |
| 835 | string subject = "Android IdentityCredential Reference Implementation"; |
| 836 | time_t validityNotBefore = time(nullptr); |
| 837 | time_t validityNotAfter = validityNotBefore + 365 * 24 * 3600; |
| 838 | |
| 839 | optional<vector<uint8_t>> signingKeyPKCS8 = support::createEcKeyPair(); |
| 840 | if (!signingKeyPKCS8) { |
| 841 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 842 | IIdentityCredentialStore::STATUS_FAILED, "Error creating signingKey")); |
| 843 | } |
| 844 | |
| 845 | optional<vector<uint8_t>> signingPublicKey = |
| 846 | support::ecKeyPairGetPublicKey(signingKeyPKCS8.value()); |
| 847 | if (!signingPublicKey) { |
| 848 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 849 | IIdentityCredentialStore::STATUS_FAILED, |
| 850 | "Error getting public part of signingKey")); |
| 851 | } |
| 852 | |
| 853 | optional<vector<uint8_t>> signingKey = support::ecKeyPairGetPrivateKey(signingKeyPKCS8.value()); |
| 854 | if (!signingKey) { |
| 855 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 856 | IIdentityCredentialStore::STATUS_FAILED, |
| 857 | "Error getting private part of signingKey")); |
| 858 | } |
| 859 | |
| 860 | optional<vector<uint8_t>> certificate = support::ecPublicKeyGenerateCertificate( |
| 861 | signingPublicKey.value(), credentialPrivKey_, serialDecimal, issuer, subject, |
| 862 | validityNotBefore, validityNotAfter); |
| 863 | if (!certificate) { |
| 864 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 865 | IIdentityCredentialStore::STATUS_FAILED, "Error creating signingKey")); |
| 866 | } |
| 867 | |
| 868 | optional<vector<uint8_t>> nonce = support::getRandom(12); |
| 869 | if (!nonce) { |
| 870 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 871 | IIdentityCredentialStore::STATUS_FAILED, "Error getting random")); |
| 872 | } |
| 873 | vector<uint8_t> docTypeAsBlob(docType_.begin(), docType_.end()); |
| 874 | optional<vector<uint8_t>> encryptedSigningKey = support::encryptAes128Gcm( |
| 875 | storageKey_, nonce.value(), signingKey.value(), docTypeAsBlob); |
| 876 | if (!encryptedSigningKey) { |
| 877 | return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 878 | IIdentityCredentialStore::STATUS_FAILED, "Error encrypting signingKey")); |
| 879 | } |
Jooyung Han | 17be89b | 2020-02-21 21:17:06 +0900 | [diff] [blame] | 880 | *outSigningKeyBlob = encryptedSigningKey.value(); |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 881 | *outSigningKeyCertificate = Certificate(); |
Jooyung Han | 17be89b | 2020-02-21 21:17:06 +0900 | [diff] [blame] | 882 | outSigningKeyCertificate->encodedCertificate = certificate.value(); |
David Zeuthen | 8160315 | 2020-02-11 22:04:24 -0500 | [diff] [blame] | 883 | return ndk::ScopedAStatus::ok(); |
| 884 | } |
| 885 | |
| 886 | } // namespace aidl::android::hardware::identity |