| /* |
| * Copyright 2019, The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #define LOG_TAG "IdentityCredential" |
| |
| #include "IdentityCredential.h" |
| #include "IdentityCredentialStore.h" |
| #include "Util.h" |
| |
| #include <android/hardware/identity/support/IdentityCredentialSupport.h> |
| |
| #include <string.h> |
| |
| #include <android-base/logging.h> |
| |
| #include <cppbor.h> |
| #include <cppbor_parse.h> |
| |
| namespace aidl::android::hardware::identity { |
| |
| using ::aidl::android::hardware::keymaster::Timestamp; |
| using ::std::optional; |
| |
| using namespace ::android::hardware::identity; |
| |
| int IdentityCredential::initialize() { |
| auto [item, _, message] = cppbor::parse(credentialData_); |
| if (item == nullptr) { |
| LOG(ERROR) << "CredentialData is not valid CBOR: " << message; |
| return IIdentityCredentialStore::STATUS_INVALID_DATA; |
| } |
| |
| const cppbor::Array* arrayItem = item->asArray(); |
| if (arrayItem == nullptr || arrayItem->size() != 3) { |
| LOG(ERROR) << "CredentialData is not an array with three elements"; |
| return IIdentityCredentialStore::STATUS_INVALID_DATA; |
| } |
| |
| const cppbor::Tstr* docTypeItem = (*arrayItem)[0]->asTstr(); |
| const cppbor::Bool* testCredentialItem = |
| ((*arrayItem)[1]->asSimple() != nullptr ? ((*arrayItem)[1]->asSimple()->asBool()) |
| : nullptr); |
| const cppbor::Bstr* encryptedCredentialKeysItem = (*arrayItem)[2]->asBstr(); |
| if (docTypeItem == nullptr || testCredentialItem == nullptr || |
| encryptedCredentialKeysItem == nullptr) { |
| LOG(ERROR) << "CredentialData unexpected item types"; |
| return IIdentityCredentialStore::STATUS_INVALID_DATA; |
| } |
| |
| docType_ = docTypeItem->value(); |
| testCredential_ = testCredentialItem->value(); |
| |
| vector<uint8_t> hardwareBoundKey; |
| if (testCredential_) { |
| hardwareBoundKey = support::getTestHardwareBoundKey(); |
| } else { |
| hardwareBoundKey = getHardwareBoundKey(); |
| } |
| |
| const vector<uint8_t>& encryptedCredentialKeys = encryptedCredentialKeysItem->value(); |
| const vector<uint8_t> docTypeVec(docType_.begin(), docType_.end()); |
| optional<vector<uint8_t>> decryptedCredentialKeys = |
| support::decryptAes128Gcm(hardwareBoundKey, encryptedCredentialKeys, docTypeVec); |
| if (!decryptedCredentialKeys) { |
| LOG(ERROR) << "Error decrypting CredentialKeys"; |
| return IIdentityCredentialStore::STATUS_INVALID_DATA; |
| } |
| |
| auto [dckItem, dckPos, dckMessage] = cppbor::parse(decryptedCredentialKeys.value()); |
| if (dckItem == nullptr) { |
| LOG(ERROR) << "Decrypted CredentialKeys is not valid CBOR: " << dckMessage; |
| return IIdentityCredentialStore::STATUS_INVALID_DATA; |
| } |
| const cppbor::Array* dckArrayItem = dckItem->asArray(); |
| if (dckArrayItem == nullptr || dckArrayItem->size() != 2) { |
| LOG(ERROR) << "Decrypted CredentialKeys is not an array with two elements"; |
| return IIdentityCredentialStore::STATUS_INVALID_DATA; |
| } |
| const cppbor::Bstr* storageKeyItem = (*dckArrayItem)[0]->asBstr(); |
| const cppbor::Bstr* credentialPrivKeyItem = (*dckArrayItem)[1]->asBstr(); |
| if (storageKeyItem == nullptr || credentialPrivKeyItem == nullptr) { |
| LOG(ERROR) << "CredentialKeys unexpected item types"; |
| return IIdentityCredentialStore::STATUS_INVALID_DATA; |
| } |
| storageKey_ = storageKeyItem->value(); |
| credentialPrivKey_ = credentialPrivKeyItem->value(); |
| |
| return IIdentityCredentialStore::STATUS_OK; |
| } |
| |
| ndk::ScopedAStatus IdentityCredential::deleteCredential( |
| vector<uint8_t>* outProofOfDeletionSignature) { |
| cppbor::Array array = {"ProofOfDeletion", docType_, testCredential_}; |
| vector<uint8_t> proofOfDeletion = array.encode(); |
| |
| optional<vector<uint8_t>> signature = support::coseSignEcDsa(credentialPrivKey_, |
| proofOfDeletion, // payload |
| {}, // additionalData |
| {}); // certificateChain |
| if (!signature) { |
| return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| IIdentityCredentialStore::STATUS_FAILED, "Error signing data")); |
| } |
| |
| *outProofOfDeletionSignature = signature.value(); |
| return ndk::ScopedAStatus::ok(); |
| } |
| |
| ndk::ScopedAStatus IdentityCredential::createEphemeralKeyPair(vector<uint8_t>* outKeyPair) { |
| optional<vector<uint8_t>> kp = support::createEcKeyPair(); |
| if (!kp) { |
| return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| IIdentityCredentialStore::STATUS_FAILED, "Error creating ephemeral key pair")); |
| } |
| |
| // Stash public key of this key-pair for later check in startRetrieval(). |
| optional<vector<uint8_t>> publicKey = support::ecKeyPairGetPublicKey(kp.value()); |
| if (!publicKey) { |
| return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| IIdentityCredentialStore::STATUS_FAILED, |
| "Error getting public part of ephemeral key pair")); |
| } |
| ephemeralPublicKey_ = publicKey.value(); |
| |
| *outKeyPair = kp.value(); |
| return ndk::ScopedAStatus::ok(); |
| } |
| |
| ndk::ScopedAStatus IdentityCredential::setReaderEphemeralPublicKey( |
| const vector<uint8_t>& publicKey) { |
| readerPublicKey_ = publicKey; |
| return ndk::ScopedAStatus::ok(); |
| } |
| |
| ndk::ScopedAStatus IdentityCredential::createAuthChallenge(int64_t* outChallenge) { |
| uint64_t challenge = 0; |
| while (challenge == 0) { |
| optional<vector<uint8_t>> bytes = support::getRandom(8); |
| if (!bytes) { |
| return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| IIdentityCredentialStore::STATUS_FAILED, |
| "Error getting random data for challenge")); |
| } |
| |
| challenge = 0; |
| for (size_t n = 0; n < bytes.value().size(); n++) { |
| challenge |= ((bytes.value())[n] << (n * 8)); |
| } |
| } |
| |
| *outChallenge = challenge; |
| return ndk::ScopedAStatus::ok(); |
| } |
| |
| // TODO: this could be a lot faster if we did all the splitting and pubkey extraction |
| // ahead of time. |
| bool checkReaderAuthentication(const SecureAccessControlProfile& profile, |
| const vector<uint8_t>& readerCertificateChain) { |
| optional<vector<uint8_t>> acpPubKey = |
| support::certificateChainGetTopMostKey(profile.readerCertificate.encodedCertificate); |
| if (!acpPubKey) { |
| LOG(ERROR) << "Error extracting public key from readerCertificate in profile"; |
| return false; |
| } |
| |
| optional<vector<vector<uint8_t>>> certificatesInChain = |
| support::certificateChainSplit(readerCertificateChain); |
| if (!certificatesInChain) { |
| LOG(ERROR) << "Error splitting readerCertificateChain"; |
| return false; |
| } |
| for (const vector<uint8_t>& certInChain : certificatesInChain.value()) { |
| optional<vector<uint8_t>> certPubKey = support::certificateChainGetTopMostKey(certInChain); |
| if (!certPubKey) { |
| LOG(ERROR) |
| << "Error extracting public key from certificate in chain presented by reader"; |
| return false; |
| } |
| if (acpPubKey.value() == certPubKey.value()) { |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| Timestamp clockGetTime() { |
| struct timespec time; |
| clock_gettime(CLOCK_MONOTONIC, &time); |
| Timestamp ts; |
| ts.milliSeconds = time.tv_sec * 1000 + time.tv_nsec / 1000000; |
| return ts; |
| } |
| |
| bool checkUserAuthentication(const SecureAccessControlProfile& profile, |
| const HardwareAuthToken& authToken, uint64_t authChallenge) { |
| if (profile.secureUserId != authToken.userId) { |
| LOG(ERROR) << "secureUserId in profile (" << profile.secureUserId |
| << ") differs from userId in authToken (" << authToken.userId << ")"; |
| return false; |
| } |
| |
| if (profile.timeoutMillis == 0) { |
| if (authToken.challenge == 0) { |
| LOG(ERROR) << "No challenge in authToken"; |
| return false; |
| } |
| |
| if (authToken.challenge != int64_t(authChallenge)) { |
| LOG(ERROR) << "Challenge in authToken doesn't match the challenge we created"; |
| return false; |
| } |
| return true; |
| } |
| |
| // Note that the Epoch for timestamps in HardwareAuthToken is at the |
| // discretion of the vendor: |
| // |
| // "[...] since some starting point (generally the most recent device |
| // boot) which all of the applications within one secure environment |
| // must agree upon." |
| // |
| // Therefore, if this software implementation is used on a device which isn't |
| // the emulator then the assumption that the epoch is the same as used in |
| // clockGetTime above will not hold. This is OK as this software |
| // implementation should never be used on a real device. |
| // |
| Timestamp now = clockGetTime(); |
| if (authToken.timestamp.milliSeconds > now.milliSeconds) { |
| LOG(ERROR) << "Timestamp in authToken (" << authToken.timestamp.milliSeconds |
| << ") is in the future (now: " << now.milliSeconds << ")"; |
| return false; |
| } |
| if (now.milliSeconds > authToken.timestamp.milliSeconds + profile.timeoutMillis) { |
| LOG(ERROR) << "Deadline for authToken (" << authToken.timestamp.milliSeconds << " + " |
| << profile.timeoutMillis << " = " |
| << (authToken.timestamp.milliSeconds + profile.timeoutMillis) |
| << ") is in the past (now: " << now.milliSeconds << ")"; |
| return false; |
| } |
| return true; |
| } |
| |
| ndk::ScopedAStatus IdentityCredential::startRetrieval( |
| const vector<SecureAccessControlProfile>& accessControlProfiles, |
| const HardwareAuthToken& authToken, const vector<uint8_t>& itemsRequest, |
| const vector<uint8_t>& signingKeyBlob, const vector<uint8_t>& sessionTranscript, |
| const vector<uint8_t>& readerSignature, const vector<int32_t>& requestCounts) { |
| if (sessionTranscript.size() > 0) { |
| auto [item, _, message] = cppbor::parse(sessionTranscript); |
| if (item == nullptr) { |
| return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| IIdentityCredentialStore::STATUS_INVALID_DATA, |
| "SessionTranscript contains invalid CBOR")); |
| } |
| sessionTranscriptItem_ = std::move(item); |
| } |
| if (numStartRetrievalCalls_ > 0) { |
| if (sessionTranscript_ != sessionTranscript) { |
| return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| IIdentityCredentialStore::STATUS_SESSION_TRANSCRIPT_MISMATCH, |
| "Passed-in SessionTranscript doesn't match previously used SessionTranscript")); |
| } |
| } |
| sessionTranscript_ = sessionTranscript; |
| |
| // If there is a signature, validate that it was made with the top-most key in the |
| // certificate chain embedded in the COSE_Sign1 structure. |
| optional<vector<uint8_t>> readerCertificateChain; |
| if (readerSignature.size() > 0) { |
| readerCertificateChain = support::coseSignGetX5Chain(readerSignature); |
| if (!readerCertificateChain) { |
| return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| IIdentityCredentialStore::STATUS_READER_SIGNATURE_CHECK_FAILED, |
| "Unable to get reader certificate chain from COSE_Sign1")); |
| } |
| |
| if (!support::certificateChainValidate(readerCertificateChain.value())) { |
| return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| IIdentityCredentialStore::STATUS_READER_SIGNATURE_CHECK_FAILED, |
| "Error validating reader certificate chain")); |
| } |
| |
| optional<vector<uint8_t>> readerPublicKey = |
| support::certificateChainGetTopMostKey(readerCertificateChain.value()); |
| if (!readerPublicKey) { |
| return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| IIdentityCredentialStore::STATUS_READER_SIGNATURE_CHECK_FAILED, |
| "Unable to get public key from reader certificate chain")); |
| } |
| |
| const vector<uint8_t>& itemsRequestBytes = itemsRequest; |
| vector<uint8_t> dataThatWasSigned = cppbor::Array() |
| .add("ReaderAuthentication") |
| .add(sessionTranscriptItem_->clone()) |
| .add(cppbor::Semantic(24, itemsRequestBytes)) |
| .encode(); |
| if (!support::coseCheckEcDsaSignature(readerSignature, |
| dataThatWasSigned, // detached content |
| readerPublicKey.value())) { |
| return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| IIdentityCredentialStore::STATUS_READER_SIGNATURE_CHECK_FAILED, |
| "readerSignature check failed")); |
| } |
| } |
| |
| // Here's where we would validate the passed-in |authToken| to assure ourselves |
| // that it comes from the e.g. biometric hardware and wasn't made up by an attacker. |
| // |
| // However this involves calculating the MAC. However this requires access |
| // to the key needed to a pre-shared key which we don't have... |
| // |
| |
| // To prevent replay-attacks, we check that the public part of the ephemeral |
| // key we previously created, is present in the DeviceEngagement part of |
| // SessionTranscript as a COSE_Key, in uncompressed form. |
| // |
| // We do this by just searching for the X and Y coordinates. |
| if (sessionTranscript.size() > 0) { |
| const cppbor::Array* array = sessionTranscriptItem_->asArray(); |
| if (array == nullptr || array->size() != 2) { |
| return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| IIdentityCredentialStore::STATUS_EPHEMERAL_PUBLIC_KEY_NOT_FOUND, |
| "SessionTranscript is not an array with two items")); |
| } |
| const cppbor::Semantic* taggedEncodedDE = (*array)[0]->asSemantic(); |
| if (taggedEncodedDE == nullptr || taggedEncodedDE->value() != 24) { |
| return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| IIdentityCredentialStore::STATUS_EPHEMERAL_PUBLIC_KEY_NOT_FOUND, |
| "First item in SessionTranscript array is not a " |
| "semantic with value 24")); |
| } |
| const cppbor::Bstr* encodedDE = (taggedEncodedDE->child())->asBstr(); |
| if (encodedDE == nullptr) { |
| return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| IIdentityCredentialStore::STATUS_EPHEMERAL_PUBLIC_KEY_NOT_FOUND, |
| "Child of semantic in first item in SessionTranscript " |
| "array is not a bstr")); |
| } |
| const vector<uint8_t>& bytesDE = encodedDE->value(); |
| |
| auto [getXYSuccess, ePubX, ePubY] = support::ecPublicKeyGetXandY(ephemeralPublicKey_); |
| if (!getXYSuccess) { |
| return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| IIdentityCredentialStore::STATUS_EPHEMERAL_PUBLIC_KEY_NOT_FOUND, |
| "Error extracting X and Y from ePub")); |
| } |
| if (sessionTranscript.size() > 0 && |
| !(memmem(bytesDE.data(), bytesDE.size(), ePubX.data(), ePubX.size()) != nullptr && |
| memmem(bytesDE.data(), bytesDE.size(), ePubY.data(), ePubY.size()) != nullptr)) { |
| return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| IIdentityCredentialStore::STATUS_EPHEMERAL_PUBLIC_KEY_NOT_FOUND, |
| "Did not find ephemeral public key's X and Y coordinates in " |
| "SessionTranscript (make sure leading zeroes are not used)")); |
| } |
| } |
| |
| // itemsRequest: If non-empty, contains request data that may be signed by the |
| // reader. The content can be defined in the way appropriate for the |
| // credential, but there are three requirements that must be met to work with |
| // this HAL: |
| if (itemsRequest.size() > 0) { |
| // 1. The content must be a CBOR-encoded structure. |
| auto [item, _, message] = cppbor::parse(itemsRequest); |
| if (item == nullptr) { |
| return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| IIdentityCredentialStore::STATUS_INVALID_ITEMS_REQUEST_MESSAGE, |
| "Error decoding CBOR in itemsRequest")); |
| } |
| |
| // 2. The CBOR structure must be a map. |
| const cppbor::Map* map = item->asMap(); |
| if (map == nullptr) { |
| return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| IIdentityCredentialStore::STATUS_INVALID_ITEMS_REQUEST_MESSAGE, |
| "itemsRequest is not a CBOR map")); |
| } |
| |
| // 3. The map must contain a key "nameSpaces" whose value contains a map, as described in |
| // the example below. |
| // |
| // NameSpaces = { |
| // + NameSpace => DataElements ; Requested data elements for each NameSpace |
| // } |
| // |
| // NameSpace = tstr |
| // |
| // DataElements = { |
| // + DataElement => IntentToRetain |
| // } |
| // |
| // DataElement = tstr |
| // IntentToRetain = bool |
| // |
| // Here's an example of an |itemsRequest| CBOR value satisfying above requirements 1. |
| // through 3.: |
| // |
| // { |
| // 'docType' : 'org.iso.18013-5.2019', |
| // 'nameSpaces' : { |
| // 'org.iso.18013-5.2019' : { |
| // 'Last name' : false, |
| // 'Birth date' : false, |
| // 'First name' : false, |
| // 'Home address' : true |
| // }, |
| // 'org.aamva.iso.18013-5.2019' : { |
| // 'Real Id' : false |
| // } |
| // } |
| // } |
| // |
| const cppbor::Map* nsMap = nullptr; |
| for (size_t n = 0; n < map->size(); n++) { |
| const auto& [keyItem, valueItem] = (*map)[n]; |
| if (keyItem->type() == cppbor::TSTR && keyItem->asTstr()->value() == "nameSpaces" && |
| valueItem->type() == cppbor::MAP) { |
| nsMap = valueItem->asMap(); |
| break; |
| } |
| } |
| if (nsMap == nullptr) { |
| return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| IIdentityCredentialStore::STATUS_INVALID_ITEMS_REQUEST_MESSAGE, |
| "No nameSpaces map in top-most map")); |
| } |
| |
| for (size_t n = 0; n < nsMap->size(); n++) { |
| auto [nsKeyItem, nsValueItem] = (*nsMap)[n]; |
| const cppbor::Tstr* nsKey = nsKeyItem->asTstr(); |
| const cppbor::Map* nsInnerMap = nsValueItem->asMap(); |
| if (nsKey == nullptr || nsInnerMap == nullptr) { |
| return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| IIdentityCredentialStore::STATUS_INVALID_ITEMS_REQUEST_MESSAGE, |
| "Type mismatch in nameSpaces map")); |
| } |
| string requestedNamespace = nsKey->value(); |
| vector<string> requestedKeys; |
| for (size_t m = 0; m < nsInnerMap->size(); m++) { |
| const auto& [innerMapKeyItem, innerMapValueItem] = (*nsInnerMap)[m]; |
| const cppbor::Tstr* nameItem = innerMapKeyItem->asTstr(); |
| const cppbor::Simple* simple = innerMapValueItem->asSimple(); |
| const cppbor::Bool* intentToRetainItem = |
| (simple != nullptr) ? simple->asBool() : nullptr; |
| if (nameItem == nullptr || intentToRetainItem == nullptr) { |
| return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| IIdentityCredentialStore::STATUS_INVALID_ITEMS_REQUEST_MESSAGE, |
| "Type mismatch in value in nameSpaces map")); |
| } |
| requestedKeys.push_back(nameItem->value()); |
| } |
| requestedNameSpacesAndNames_[requestedNamespace] = requestedKeys; |
| } |
| } |
| |
| // Finally, validate all the access control profiles in the requestData. |
| bool haveAuthToken = (authToken.mac.size() > 0); |
| for (const auto& profile : accessControlProfiles) { |
| if (!secureAccessControlProfileCheckMac(profile, storageKey_)) { |
| return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| IIdentityCredentialStore::STATUS_INVALID_DATA, |
| "Error checking MAC for profile")); |
| } |
| int accessControlCheck = IIdentityCredentialStore::STATUS_OK; |
| if (profile.userAuthenticationRequired) { |
| if (!haveAuthToken || !checkUserAuthentication(profile, authToken, authChallenge_)) { |
| accessControlCheck = IIdentityCredentialStore::STATUS_USER_AUTHENTICATION_FAILED; |
| } |
| } else if (profile.readerCertificate.encodedCertificate.size() > 0) { |
| if (!readerCertificateChain || |
| !checkReaderAuthentication(profile, readerCertificateChain.value())) { |
| accessControlCheck = IIdentityCredentialStore::STATUS_READER_AUTHENTICATION_FAILED; |
| } |
| } |
| profileIdToAccessCheckResult_[profile.id] = accessControlCheck; |
| } |
| |
| deviceNameSpacesMap_ = cppbor::Map(); |
| currentNameSpaceDeviceNameSpacesMap_ = cppbor::Map(); |
| |
| requestCountsRemaining_ = requestCounts; |
| currentNameSpace_ = ""; |
| |
| itemsRequest_ = itemsRequest; |
| signingKeyBlob_ = signingKeyBlob; |
| |
| numStartRetrievalCalls_ += 1; |
| return ndk::ScopedAStatus::ok(); |
| } |
| |
| ndk::ScopedAStatus IdentityCredential::startRetrieveEntryValue( |
| const string& nameSpace, const string& name, int32_t entrySize, |
| const vector<int32_t>& accessControlProfileIds) { |
| if (name.empty()) { |
| return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| IIdentityCredentialStore::STATUS_INVALID_DATA, "Name cannot be empty")); |
| } |
| if (nameSpace.empty()) { |
| return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| IIdentityCredentialStore::STATUS_INVALID_DATA, "Name space cannot be empty")); |
| } |
| |
| if (requestCountsRemaining_.size() == 0) { |
| return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| IIdentityCredentialStore::STATUS_INVALID_DATA, |
| "No more name spaces left to go through")); |
| } |
| |
| if (currentNameSpace_ == "") { |
| // First call. |
| currentNameSpace_ = nameSpace; |
| } |
| |
| if (nameSpace == currentNameSpace_) { |
| // Same namespace. |
| if (requestCountsRemaining_[0] == 0) { |
| return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| IIdentityCredentialStore::STATUS_INVALID_DATA, |
| "No more entries to be retrieved in current name space")); |
| } |
| requestCountsRemaining_[0] -= 1; |
| } else { |
| // New namespace. |
| if (requestCountsRemaining_[0] != 0) { |
| return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| IIdentityCredentialStore::STATUS_INVALID_DATA, |
| "Moved to new name space but one or more entries need to be retrieved " |
| "in current name space")); |
| } |
| if (currentNameSpaceDeviceNameSpacesMap_.size() > 0) { |
| deviceNameSpacesMap_.add(currentNameSpace_, |
| std::move(currentNameSpaceDeviceNameSpacesMap_)); |
| } |
| currentNameSpaceDeviceNameSpacesMap_ = cppbor::Map(); |
| |
| requestCountsRemaining_.erase(requestCountsRemaining_.begin()); |
| currentNameSpace_ = nameSpace; |
| } |
| |
| // It's permissible to have an empty itemsRequest... but if non-empty you can |
| // only request what was specified in said itemsRequest. Enforce that. |
| if (itemsRequest_.size() > 0) { |
| const auto& it = requestedNameSpacesAndNames_.find(nameSpace); |
| if (it == requestedNameSpacesAndNames_.end()) { |
| return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| IIdentityCredentialStore::STATUS_NOT_IN_REQUEST_MESSAGE, |
| "Name space was not requested in startRetrieval")); |
| } |
| const auto& dataItemNames = it->second; |
| if (std::find(dataItemNames.begin(), dataItemNames.end(), name) == dataItemNames.end()) { |
| return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| IIdentityCredentialStore::STATUS_NOT_IN_REQUEST_MESSAGE, |
| "Data item name in name space was not requested in startRetrieval")); |
| } |
| } |
| |
| // Enforce access control. |
| // |
| // Access is granted if at least one of the profiles grants access. |
| // |
| // If an item is configured without any profiles, access is denied. |
| // |
| int accessControl = IIdentityCredentialStore::STATUS_NO_ACCESS_CONTROL_PROFILES; |
| for (auto id : accessControlProfileIds) { |
| auto search = profileIdToAccessCheckResult_.find(id); |
| if (search == profileIdToAccessCheckResult_.end()) { |
| return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| IIdentityCredentialStore::STATUS_INVALID_DATA, |
| "Requested entry with unvalidated profile id")); |
| } |
| int accessControlForProfile = search->second; |
| if (accessControlForProfile == IIdentityCredentialStore::STATUS_OK) { |
| accessControl = IIdentityCredentialStore::STATUS_OK; |
| break; |
| } |
| accessControl = accessControlForProfile; |
| } |
| if (accessControl != IIdentityCredentialStore::STATUS_OK) { |
| return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| int(accessControl), "Access control check failed")); |
| } |
| |
| entryAdditionalData_ = entryCreateAdditionalData(nameSpace, name, accessControlProfileIds); |
| |
| currentName_ = name; |
| entryRemainingBytes_ = entrySize; |
| entryValue_.resize(0); |
| |
| return ndk::ScopedAStatus::ok(); |
| } |
| |
| ndk::ScopedAStatus IdentityCredential::retrieveEntryValue(const vector<uint8_t>& encryptedContent, |
| vector<uint8_t>* outContent) { |
| optional<vector<uint8_t>> content = |
| support::decryptAes128Gcm(storageKey_, encryptedContent, entryAdditionalData_); |
| if (!content) { |
| return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| IIdentityCredentialStore::STATUS_INVALID_DATA, "Error decrypting data")); |
| } |
| |
| size_t chunkSize = content.value().size(); |
| |
| if (chunkSize > entryRemainingBytes_) { |
| LOG(ERROR) << "Retrieved chunk of size " << chunkSize |
| << " is bigger than remaining space of size " << entryRemainingBytes_; |
| return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| IIdentityCredentialStore::STATUS_INVALID_DATA, |
| "Retrieved chunk is bigger than remaining space")); |
| } |
| |
| entryRemainingBytes_ -= chunkSize; |
| if (entryRemainingBytes_ > 0) { |
| if (chunkSize != IdentityCredentialStore::kGcmChunkSize) { |
| return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| IIdentityCredentialStore::STATUS_INVALID_DATA, |
| "Retrieved non-final chunk of size which isn't kGcmChunkSize")); |
| } |
| } |
| |
| entryValue_.insert(entryValue_.end(), content.value().begin(), content.value().end()); |
| |
| if (entryRemainingBytes_ == 0) { |
| auto [entryValueItem, _, message] = cppbor::parse(entryValue_); |
| if (entryValueItem == nullptr) { |
| return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| IIdentityCredentialStore::STATUS_INVALID_DATA, |
| "Retrieved data which is invalid CBOR")); |
| } |
| currentNameSpaceDeviceNameSpacesMap_.add(currentName_, std::move(entryValueItem)); |
| } |
| |
| *outContent = content.value(); |
| return ndk::ScopedAStatus::ok(); |
| } |
| |
| ndk::ScopedAStatus IdentityCredential::finishRetrieval(vector<uint8_t>* outMac, |
| vector<uint8_t>* outDeviceNameSpaces) { |
| if (currentNameSpaceDeviceNameSpacesMap_.size() > 0) { |
| deviceNameSpacesMap_.add(currentNameSpace_, |
| std::move(currentNameSpaceDeviceNameSpacesMap_)); |
| } |
| vector<uint8_t> encodedDeviceNameSpaces = deviceNameSpacesMap_.encode(); |
| |
| // If there's no signing key or no sessionTranscript or no reader ephemeral |
| // public key, we return the empty MAC. |
| optional<vector<uint8_t>> mac; |
| if (signingKeyBlob_.size() > 0 && sessionTranscript_.size() > 0 && |
| readerPublicKey_.size() > 0) { |
| cppbor::Array array; |
| array.add("DeviceAuthentication"); |
| array.add(sessionTranscriptItem_->clone()); |
| array.add(docType_); |
| array.add(cppbor::Semantic(24, encodedDeviceNameSpaces)); |
| vector<uint8_t> encodedDeviceAuthentication = array.encode(); |
| |
| vector<uint8_t> docTypeAsBlob(docType_.begin(), docType_.end()); |
| optional<vector<uint8_t>> signingKey = |
| support::decryptAes128Gcm(storageKey_, signingKeyBlob_, docTypeAsBlob); |
| if (!signingKey) { |
| return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| IIdentityCredentialStore::STATUS_INVALID_DATA, |
| "Error decrypting signingKeyBlob")); |
| } |
| |
| optional<vector<uint8_t>> sharedSecret = |
| support::ecdh(readerPublicKey_, signingKey.value()); |
| if (!sharedSecret) { |
| return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| IIdentityCredentialStore::STATUS_FAILED, "Error doing ECDH")); |
| } |
| |
| vector<uint8_t> salt = {0x00}; |
| vector<uint8_t> info = {}; |
| optional<vector<uint8_t>> derivedKey = support::hkdf(sharedSecret.value(), salt, info, 32); |
| if (!derivedKey) { |
| return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| IIdentityCredentialStore::STATUS_FAILED, |
| "Error deriving key from shared secret")); |
| } |
| |
| mac = support::coseMac0(derivedKey.value(), {}, // payload |
| encodedDeviceAuthentication); // additionalData |
| if (!mac) { |
| return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| IIdentityCredentialStore::STATUS_FAILED, "Error MACing data")); |
| } |
| } |
| |
| *outMac = mac.value_or(vector<uint8_t>({})); |
| *outDeviceNameSpaces = encodedDeviceNameSpaces; |
| return ndk::ScopedAStatus::ok(); |
| } |
| |
| ndk::ScopedAStatus IdentityCredential::generateSigningKeyPair( |
| vector<uint8_t>* outSigningKeyBlob, Certificate* outSigningKeyCertificate) { |
| string serialDecimal = "0"; // TODO: set serial to something unique |
| string issuer = "Android Open Source Project"; |
| string subject = "Android IdentityCredential Reference Implementation"; |
| time_t validityNotBefore = time(nullptr); |
| time_t validityNotAfter = validityNotBefore + 365 * 24 * 3600; |
| |
| optional<vector<uint8_t>> signingKeyPKCS8 = support::createEcKeyPair(); |
| if (!signingKeyPKCS8) { |
| return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| IIdentityCredentialStore::STATUS_FAILED, "Error creating signingKey")); |
| } |
| |
| optional<vector<uint8_t>> signingPublicKey = |
| support::ecKeyPairGetPublicKey(signingKeyPKCS8.value()); |
| if (!signingPublicKey) { |
| return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| IIdentityCredentialStore::STATUS_FAILED, |
| "Error getting public part of signingKey")); |
| } |
| |
| optional<vector<uint8_t>> signingKey = support::ecKeyPairGetPrivateKey(signingKeyPKCS8.value()); |
| if (!signingKey) { |
| return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| IIdentityCredentialStore::STATUS_FAILED, |
| "Error getting private part of signingKey")); |
| } |
| |
| optional<vector<uint8_t>> certificate = support::ecPublicKeyGenerateCertificate( |
| signingPublicKey.value(), credentialPrivKey_, serialDecimal, issuer, subject, |
| validityNotBefore, validityNotAfter); |
| if (!certificate) { |
| return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| IIdentityCredentialStore::STATUS_FAILED, "Error creating signingKey")); |
| } |
| |
| optional<vector<uint8_t>> nonce = support::getRandom(12); |
| if (!nonce) { |
| return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| IIdentityCredentialStore::STATUS_FAILED, "Error getting random")); |
| } |
| vector<uint8_t> docTypeAsBlob(docType_.begin(), docType_.end()); |
| optional<vector<uint8_t>> encryptedSigningKey = support::encryptAes128Gcm( |
| storageKey_, nonce.value(), signingKey.value(), docTypeAsBlob); |
| if (!encryptedSigningKey) { |
| return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| IIdentityCredentialStore::STATUS_FAILED, "Error encrypting signingKey")); |
| } |
| *outSigningKeyBlob = encryptedSigningKey.value(); |
| *outSigningKeyCertificate = Certificate(); |
| outSigningKeyCertificate->encodedCertificate = certificate.value(); |
| return ndk::ScopedAStatus::ok(); |
| } |
| |
| } // namespace aidl::android::hardware::identity |