Identity Credential: Switch default implementation to use libeic.
Introduce platform-neutral C library ("libeic") which can be used to
implement an Identity Credential Trusted Application/Applet in Secure
Hardware.
The libeic library is intentionally low-level, has no dependencies
(not even libc), uses very little run-time memory (less than 500 bytes
during a provisioning or presentation session), and doesn't
dynamically allocate any memory. Crypto routines are provided by the
library user through a simple crypto interface defined in EicOps.
Also provide an Android-side HAL implementation designed to
communicate with libeic running in Secure Hardware outside
Android. Abstract out communications between HAL and TA in a couple of
SecureHardwareProxy* classes which mimic libeic 1:1.
The default implementation of the HAL is a combination of the
aforementioned HAL using libeic in-process backed by BoringSSL for the
crypto bits.
Test: atest VtsHalIdentityTargetTest
Test: atest android.security.identity.cts
Bug: 170146643
Change-Id: I3bf43fa7fd9362f94023052591801f2094a04607
diff --git a/identity/aidl/default/common/IdentityCredential.cpp b/identity/aidl/default/common/IdentityCredential.cpp
new file mode 100644
index 0000000..270fcfa
--- /dev/null
+++ b/identity/aidl/default/common/IdentityCredential.cpp
@@ -0,0 +1,836 @@
+/*
+ * 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 <android/hardware/identity/support/IdentityCredentialSupport.h>
+
+#include <string.h>
+
+#include <android-base/logging.h>
+#include <android-base/stringprintf.h>
+
+#include <cppbor.h>
+#include <cppbor_parse.h>
+
+#include "FakeSecureHardwareProxy.h"
+
+namespace aidl::android::hardware::identity {
+
+using ::aidl::android::hardware::keymaster::Timestamp;
+using ::android::base::StringPrintf;
+using ::std::optional;
+
+using namespace ::android::hardware::identity;
+
+int IdentityCredential::initialize() {
+ if (credentialData_.size() == 0) {
+ LOG(ERROR) << "CredentialData is empty";
+ return IIdentityCredentialStore::STATUS_INVALID_DATA;
+ }
+ 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();
+
+ const vector<uint8_t>& encryptedCredentialKeys = encryptedCredentialKeysItem->value();
+
+ if (encryptedCredentialKeys.size() != 80) {
+ LOG(ERROR) << "Unexpected size for encrypted CredentialKeys";
+ return IIdentityCredentialStore::STATUS_INVALID_DATA;
+ }
+
+ if (!hwProxy_->initialize(testCredential_, docType_, encryptedCredentialKeys)) {
+ LOG(ERROR) << "hwProxy->initialize failed";
+ return false;
+ }
+
+ return IIdentityCredentialStore::STATUS_OK;
+}
+
+ndk::ScopedAStatus IdentityCredential::deleteCredential(
+ vector<uint8_t>* outProofOfDeletionSignature) {
+ cppbor::Array array = {"ProofOfDeletion", docType_, testCredential_};
+ vector<uint8_t> proofOfDeletionCbor = array.encode();
+ vector<uint8_t> podDigest = support::sha256(proofOfDeletionCbor);
+
+ optional<vector<uint8_t>> signatureOfToBeSigned =
+ hwProxy_->deleteCredential(docType_, proofOfDeletionCbor.size());
+ if (!signatureOfToBeSigned) {
+ return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage(
+ IIdentityCredentialStore::STATUS_FAILED, "Error signing ProofOfDeletion"));
+ }
+
+ optional<vector<uint8_t>> signature =
+ support::coseSignEcDsaWithSignature(signatureOfToBeSigned.value(),
+ proofOfDeletionCbor, // data
+ {}); // 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>> ephemeralPriv = hwProxy_->createEphemeralKeyPair();
+ if (!ephemeralPriv) {
+ return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage(
+ IIdentityCredentialStore::STATUS_FAILED, "Error creating ephemeral key"));
+ }
+ optional<vector<uint8_t>> keyPair = support::ecPrivateKeyToKeyPair(ephemeralPriv.value());
+ if (!keyPair) {
+ 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(keyPair.value());
+ if (!publicKey) {
+ LOG(ERROR) << "Error getting public part of ephemeral key pair";
+ return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage(
+ IIdentityCredentialStore::STATUS_FAILED,
+ "Error getting public part of ephemeral key pair"));
+ }
+ ephemeralPublicKey_ = publicKey.value();
+
+ *outKeyPair = keyPair.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) {
+ optional<uint64_t> challenge = hwProxy_->createAuthChallenge();
+ if (!challenge) {
+ return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage(
+ IIdentityCredentialStore::STATUS_FAILED, "Error generating challenge"));
+ }
+ *outChallenge = challenge.value();
+ return ndk::ScopedAStatus::ok();
+}
+
+ndk::ScopedAStatus IdentityCredential::setRequestedNamespaces(
+ const vector<RequestNamespace>& requestNamespaces) {
+ requestNamespaces_ = requestNamespaces;
+ return ndk::ScopedAStatus::ok();
+}
+
+ndk::ScopedAStatus IdentityCredential::setVerificationToken(
+ const VerificationToken& verificationToken) {
+ verificationToken_ = verificationToken;
+ return ndk::ScopedAStatus::ok();
+}
+
+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) {
+ std::unique_ptr<cppbor::Item> sessionTranscriptItem;
+ 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) {
+ LOG(ERROR) << "Session Transcript changed";
+ return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage(
+ IIdentityCredentialStore::STATUS_SESSION_TRANSCRIPT_MISMATCH,
+ "Passed-in SessionTranscript doesn't match previously used SessionTranscript"));
+ }
+ }
+ sessionTranscript_ = sessionTranscript;
+
+ // This resets various state in the TA...
+ if (!hwProxy_->startRetrieveEntries()) {
+ return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage(
+ IIdentityCredentialStore::STATUS_FAILED, "Error starting retrieving entries"));
+ }
+
+ optional<vector<uint8_t>> signatureOfToBeSigned;
+ if (readerSignature.size() > 0) {
+ signatureOfToBeSigned = support::coseSignGetSignature(readerSignature);
+ if (!signatureOfToBeSigned) {
+ return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage(
+ IIdentityCredentialStore::STATUS_READER_SIGNATURE_CHECK_FAILED,
+ "Error extracting signatureOfToBeSigned from COSE_Sign1"));
+ }
+ }
+
+ // Feed the auth token to secure hardware.
+ if (!hwProxy_->setAuthToken(authToken.challenge, authToken.userId, authToken.authenticatorId,
+ int(authToken.authenticatorType), authToken.timestamp.milliSeconds,
+ authToken.mac, verificationToken_.challenge,
+ verificationToken_.timestamp.milliSeconds,
+ int(verificationToken_.securityLevel), verificationToken_.mac)) {
+ return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage(
+ IIdentityCredentialStore::STATUS_INVALID_DATA, "Invalid Auth Token"));
+ }
+
+ // We'll be feeding ACPs interleaved with certificates from the reader
+ // certificate chain...
+ vector<SecureAccessControlProfile> remainingAcps = accessControlProfiles;
+
+ // ... and we'll use those ACPs to build up a 32-bit mask indicating which
+ // of the possible 32 ACPs grants access.
+ uint32_t accessControlProfileMask = 0;
+
+ // 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"));
+ }
+
+ // First, feed all the reader certificates to the secure hardware. We start
+ // at the end..
+ optional<vector<vector<uint8_t>>> splitCerts =
+ support::certificateChainSplit(readerCertificateChain.value());
+ if (!splitCerts || splitCerts.value().size() == 0) {
+ return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage(
+ IIdentityCredentialStore::STATUS_READER_SIGNATURE_CHECK_FAILED,
+ "Error splitting certificate chain from COSE_Sign1"));
+ }
+ for (ssize_t n = splitCerts.value().size() - 1; n >= 0; --n) {
+ const vector<uint8_t>& x509Cert = splitCerts.value()[n];
+ if (!hwProxy_->pushReaderCert(x509Cert)) {
+ return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage(
+ IIdentityCredentialStore::STATUS_READER_SIGNATURE_CHECK_FAILED,
+ StringPrintf("Error validating reader certificate %zd", n).c_str()));
+ }
+
+ // If we have ACPs for that particular certificate, send them to the
+ // TA right now...
+ //
+ // Remember in this case certificate equality is done by comparing public keys,
+ // not bitwise comparison of the certificates.
+ //
+ optional<vector<uint8_t>> x509CertPubKey =
+ support::certificateChainGetTopMostKey(x509Cert);
+ if (!x509CertPubKey) {
+ return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage(
+ IIdentityCredentialStore::STATUS_FAILED,
+ StringPrintf("Error getting public key from reader certificate %zd", n)
+ .c_str()));
+ }
+ vector<SecureAccessControlProfile>::iterator it = remainingAcps.begin();
+ while (it != remainingAcps.end()) {
+ const SecureAccessControlProfile& profile = *it;
+ if (profile.readerCertificate.encodedCertificate.size() == 0) {
+ ++it;
+ continue;
+ }
+ optional<vector<uint8_t>> profilePubKey = support::certificateChainGetTopMostKey(
+ profile.readerCertificate.encodedCertificate);
+ if (!profilePubKey) {
+ return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage(
+ IIdentityCredentialStore::STATUS_FAILED,
+ "Error getting public key from profile"));
+ }
+ if (profilePubKey.value() == x509CertPubKey.value()) {
+ optional<bool> res = hwProxy_->validateAccessControlProfile(
+ profile.id, profile.readerCertificate.encodedCertificate,
+ profile.userAuthenticationRequired, profile.timeoutMillis,
+ profile.secureUserId, profile.mac);
+ if (!res) {
+ return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage(
+ IIdentityCredentialStore::STATUS_INVALID_DATA,
+ "Error validating access control profile"));
+ }
+ if (res.value()) {
+ accessControlProfileMask |= (1 << profile.id);
+ }
+ it = remainingAcps.erase(it);
+ } else {
+ ++it;
+ }
+ }
+ }
+
+ // ... then pass the request message and have the TA check it's signed by the
+ // key in last certificate we pushed.
+ if (sessionTranscript.size() > 0 && itemsRequest.size() > 0 && readerSignature.size() > 0) {
+ optional<vector<uint8_t>> tbsSignature = support::coseSignGetSignature(readerSignature);
+ if (!tbsSignature) {
+ return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage(
+ IIdentityCredentialStore::STATUS_READER_SIGNATURE_CHECK_FAILED,
+ "Error extracting toBeSigned from COSE_Sign1"));
+ }
+ optional<int> coseSignAlg = support::coseSignGetAlg(readerSignature);
+ if (!coseSignAlg) {
+ return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage(
+ IIdentityCredentialStore::STATUS_READER_SIGNATURE_CHECK_FAILED,
+ "Error extracting signature algorithm from COSE_Sign1"));
+ }
+ if (!hwProxy_->validateRequestMessage(sessionTranscript, itemsRequest,
+ coseSignAlg.value(), tbsSignature.value())) {
+ return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage(
+ IIdentityCredentialStore::STATUS_READER_SIGNATURE_CHECK_FAILED,
+ "readerMessage is not signed by top-level certificate"));
+ }
+ }
+ }
+
+ // Feed remaining access control profiles...
+ for (const SecureAccessControlProfile& profile : remainingAcps) {
+ optional<bool> res = hwProxy_->validateAccessControlProfile(
+ profile.id, profile.readerCertificate.encodedCertificate,
+ profile.userAuthenticationRequired, profile.timeoutMillis, profile.secureUserId,
+ profile.mac);
+ if (!res) {
+ return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage(
+ IIdentityCredentialStore::STATUS_INVALID_DATA,
+ "Error validating access control profile"));
+ }
+ if (res.value()) {
+ accessControlProfileMask |= (1 << profile.id);
+ }
+ }
+
+ // TODO: move this check to the TA
+#if 1
+ // 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) {
+ 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(sessionTranscript.data(), sessionTranscript.size(), ePubX.data(),
+ ePubX.size()) != nullptr &&
+ memmem(sessionTranscript.data(), sessionTranscript.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)"));
+ }
+ }
+#endif
+
+ // 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();
+ set<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.insert(nameItem->value());
+ }
+ requestedNameSpacesAndNames_[requestedNamespace] = requestedKeys;
+ }
+ }
+
+ deviceNameSpacesMap_ = cppbor::Map();
+ currentNameSpaceDeviceNameSpacesMap_ = cppbor::Map();
+
+ requestCountsRemaining_ = requestCounts;
+ currentNameSpace_ = "";
+
+ itemsRequest_ = itemsRequest;
+ signingKeyBlob_ = signingKeyBlob;
+
+ // calculate the size of DeviceNameSpaces. We need to know it ahead of time.
+ calcDeviceNameSpacesSize(accessControlProfileMask);
+
+ // Count the number of non-empty namespaces
+ size_t numNamespacesWithValues = 0;
+ for (size_t n = 0; n < expectedNumEntriesPerNamespace_.size(); n++) {
+ if (expectedNumEntriesPerNamespace_[n] > 0) {
+ numNamespacesWithValues += 1;
+ }
+ }
+
+ // Finally, pass info so the HMAC key can be derived and the TA can start
+ // creating the DeviceNameSpaces CBOR...
+ if (sessionTranscript_.size() > 0 && readerPublicKey_.size() > 0 && signingKeyBlob.size() > 0) {
+ // We expect the reader ephemeral public key to be same size and curve
+ // as the ephemeral key we generated (e.g. P-256 key), otherwise ECDH
+ // won't work. So its length should be 65 bytes and it should be
+ // starting with 0x04.
+ if (readerPublicKey_.size() != 65 || readerPublicKey_[0] != 0x04) {
+ return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage(
+ IIdentityCredentialStore::STATUS_FAILED,
+ "Reader public key is not in expected format"));
+ }
+ vector<uint8_t> pubKeyP256(readerPublicKey_.begin() + 1, readerPublicKey_.end());
+ if (!hwProxy_->calcMacKey(sessionTranscript_, pubKeyP256, signingKeyBlob, docType_,
+ numNamespacesWithValues, expectedDeviceNameSpacesSize_)) {
+ return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage(
+ IIdentityCredentialStore::STATUS_FAILED, "Error starting retrieving entries"));
+ }
+ }
+
+ numStartRetrievalCalls_ += 1;
+ return ndk::ScopedAStatus::ok();
+}
+
+size_t cborNumBytesForLength(size_t length) {
+ if (length < 24) {
+ return 0;
+ } else if (length <= 0xff) {
+ return 1;
+ } else if (length <= 0xffff) {
+ return 2;
+ } else if (length <= 0xffffffff) {
+ return 4;
+ }
+ return 8;
+}
+
+size_t cborNumBytesForTstr(const string& value) {
+ return 1 + cborNumBytesForLength(value.size()) + value.size();
+}
+
+void IdentityCredential::calcDeviceNameSpacesSize(uint32_t accessControlProfileMask) {
+ /*
+ * This is how DeviceNameSpaces is defined:
+ *
+ * DeviceNameSpaces = {
+ * * NameSpace => DeviceSignedItems
+ * }
+ * DeviceSignedItems = {
+ * + DataItemName => DataItemValue
+ * }
+ *
+ * Namespace = tstr
+ * DataItemName = tstr
+ * DataItemValue = any
+ *
+ * This function will calculate its length using knowledge of how CBOR is
+ * encoded.
+ */
+ size_t ret = 0;
+ vector<unsigned int> numEntriesPerNamespace;
+ for (const RequestNamespace& rns : requestNamespaces_) {
+ vector<RequestDataItem> itemsToInclude;
+
+ for (const RequestDataItem& rdi : rns.items) {
+ // If we have a CBOR request message, skip if item isn't in it
+ if (itemsRequest_.size() > 0) {
+ const auto& it = requestedNameSpacesAndNames_.find(rns.namespaceName);
+ if (it == requestedNameSpacesAndNames_.end()) {
+ continue;
+ }
+ const set<string>& dataItemNames = it->second;
+ if (dataItemNames.find(rdi.name) == dataItemNames.end()) {
+ continue;
+ }
+ }
+
+ // Access is granted if at least one of the profiles grants access.
+ //
+ // If an item is configured without any profiles, access is denied.
+ //
+ bool authorized = false;
+ for (auto id : rdi.accessControlProfileIds) {
+ if (accessControlProfileMask & (1 << id)) {
+ authorized = true;
+ break;
+ }
+ }
+ if (!authorized) {
+ continue;
+ }
+
+ itemsToInclude.push_back(rdi);
+ }
+
+ numEntriesPerNamespace.push_back(itemsToInclude.size());
+
+ // If no entries are to be in the namespace, we don't include it in
+ // the CBOR...
+ if (itemsToInclude.size() == 0) {
+ continue;
+ }
+
+ // Key: NameSpace
+ ret += cborNumBytesForTstr(rns.namespaceName);
+
+ // Value: Open the DeviceSignedItems map
+ ret += 1 + cborNumBytesForLength(itemsToInclude.size());
+
+ for (const RequestDataItem& item : itemsToInclude) {
+ // Key: DataItemName
+ ret += cborNumBytesForTstr(item.name);
+
+ // Value: DataItemValue - entryData.size is the length of serialized CBOR so we use
+ // that.
+ ret += item.size;
+ }
+ }
+
+ // Now that we know the number of namespaces with values, we know how many
+ // bytes the DeviceNamespaces map in the beginning is going to take up.
+ ret += 1 + cborNumBytesForLength(numEntriesPerNamespace.size());
+
+ expectedDeviceNameSpacesSize_ = ret;
+ expectedNumEntriesPerNamespace_ = numEntriesPerNamespace;
+}
+
+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"));
+ }
+
+ bool newNamespace;
+ if (currentNameSpace_ == "") {
+ // First call.
+ currentNameSpace_ = nameSpace;
+ newNamespace = true;
+ }
+
+ 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;
+ newNamespace = true;
+ }
+
+ // 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 set<string>& dataItemNames = it->second;
+ if (dataItemNames.find(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"));
+ }
+ }
+
+ unsigned int newNamespaceNumEntries = 0;
+ if (newNamespace) {
+ if (expectedNumEntriesPerNamespace_.size() == 0) {
+ return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage(
+ IIdentityCredentialStore::STATUS_INVALID_DATA,
+ "No more populated name spaces left to go through"));
+ }
+ newNamespaceNumEntries = expectedNumEntriesPerNamespace_[0];
+ expectedNumEntriesPerNamespace_.erase(expectedNumEntriesPerNamespace_.begin());
+ }
+
+ // Access control is enforced in the secure hardware.
+ //
+ // ... except for STATUS_NOT_IN_REQUEST_MESSAGE, that's handled above (TODO:
+ // consolidate).
+ //
+ AccessCheckResult res = hwProxy_->startRetrieveEntryValue(
+ nameSpace, name, newNamespaceNumEntries, entrySize, accessControlProfileIds);
+ switch (res) {
+ case AccessCheckResult::kOk:
+ /* Do nothing. */
+ break;
+ case AccessCheckResult::kFailed:
+ return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage(
+ IIdentityCredentialStore::STATUS_FAILED,
+ "Access control check failed (failed)"));
+ break;
+ case AccessCheckResult::kNoAccessControlProfiles:
+ return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage(
+ IIdentityCredentialStore::STATUS_NO_ACCESS_CONTROL_PROFILES,
+ "Access control check failed (no access control profiles)"));
+ break;
+ case AccessCheckResult::kUserAuthenticationFailed:
+ return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage(
+ IIdentityCredentialStore::STATUS_USER_AUTHENTICATION_FAILED,
+ "Access control check failed (user auth)"));
+ break;
+ case AccessCheckResult::kReaderAuthenticationFailed:
+ return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage(
+ IIdentityCredentialStore::STATUS_READER_AUTHENTICATION_FAILED,
+ "Access control check failed (reader auth)"));
+ break;
+ }
+
+ currentName_ = name;
+ currentAccessControlProfileIds_ = accessControlProfileIds;
+ 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 = hwProxy_->retrieveEntryValue(
+ encryptedContent, currentNameSpace_, currentName_, currentAccessControlProfileIds_);
+ 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 (encodedDeviceNameSpaces.size() != expectedDeviceNameSpacesSize_) {
+ LOG(ERROR) << "encodedDeviceNameSpaces is " << encodedDeviceNameSpaces.size() << " bytes, "
+ << "was expecting " << expectedDeviceNameSpacesSize_;
+ return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage(
+ IIdentityCredentialStore::STATUS_INVALID_DATA,
+ StringPrintf(
+ "Unexpected CBOR size %zd for encodedDeviceNameSpaces, was expecting %zd",
+ encodedDeviceNameSpaces.size(), expectedDeviceNameSpacesSize_)
+ .c_str()));
+ }
+
+ // 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) {
+ optional<vector<uint8_t>> digestToBeMaced = hwProxy_->finishRetrieval();
+ if (!digestToBeMaced || digestToBeMaced.value().size() != 32) {
+ return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage(
+ IIdentityCredentialStore::STATUS_INVALID_DATA,
+ "Error generating digestToBeMaced"));
+ }
+ // Now construct COSE_Mac0 from the returned MAC...
+ mac = support::coseMacWithDigest(digestToBeMaced.value(), {} /* data */);
+ }
+
+ *outMac = mac.value_or(vector<uint8_t>({}));
+ *outDeviceNameSpaces = encodedDeviceNameSpaces;
+ return ndk::ScopedAStatus::ok();
+}
+
+ndk::ScopedAStatus IdentityCredential::generateSigningKeyPair(
+ vector<uint8_t>* outSigningKeyBlob, Certificate* outSigningKeyCertificate) {
+ time_t now = time(NULL);
+ optional<pair<vector<uint8_t>, vector<uint8_t>>> pair =
+ hwProxy_->generateSigningKeyPair(docType_, now);
+ if (!pair) {
+ return ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage(
+ IIdentityCredentialStore::STATUS_FAILED, "Error creating signingKey"));
+ }
+
+ *outSigningKeyCertificate = Certificate();
+ outSigningKeyCertificate->encodedCertificate = pair->first;
+
+ *outSigningKeyBlob = pair->second;
+ return ndk::ScopedAStatus::ok();
+}
+
+} // namespace aidl::android::hardware::identity