identity/WritableCredential.cpp - android_system_security - Gitiles

 /*
  * Copyright (c) 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 "WritableCredential"

 #include <android-base/logging.h>
 #include <android/hardware/identity/support/IdentityCredentialSupport.h>
 #include <android/security/identity/ICredentialStore.h>
 #include <binder/IPCThreadState.h>
 #include <cppbor.h>
 #include <cppbor_parse.h>
 #include <keystore/keystore_attestation_id.h>

 #include "CredentialData.h"
 #include "Util.h"
 #include "WritableCredential.h"

 namespace android {
 namespace security {
 namespace identity {

 using ::std::pair;

 using ::android::hardware::identity::SecureAccessControlProfile;

 using ::android::hardware::identity::support::chunkVector;

 WritableCredential::WritableCredential(const string& dataPath, const string& credentialName,
                                        const string& docType, size_t dataChunkSize,
                                        sp<IWritableIdentityCredential> halBinder)
     : dataPath_(dataPath), credentialName_(credentialName), docType_(docType),
       dataChunkSize_(dataChunkSize), halBinder_(halBinder) {}

 WritableCredential::~WritableCredential() {}

 Status WritableCredential::ensureAttestationCertificateExists(const vector<uint8_t>& challenge) {
     if (!attestationCertificate_.empty()) {
         return Status::ok();
     }

     const int32_t callingUid = IPCThreadState::self()->getCallingUid();
     auto asn1AttestationId = android::security::gather_attestation_application_id(callingUid);
     if (!asn1AttestationId.isOk()) {
         LOG(ERROR) << "Failed gathering AttestionApplicationId";
         return Status::fromServiceSpecificError(ICredentialStore::ERROR_GENERIC,
                                                 "Failed gathering AttestionApplicationId");
     }

     vector<Certificate> certificateChain;
     Status status = halBinder_->getAttestationCertificate(asn1AttestationId.value(), challenge,
                                                           &certificateChain);
     if (!status.isOk()) {
         LOG(ERROR) << "Error calling getAttestationCertificate()";
         return halStatusToGenericError(status);
     }

     vector<vector<uint8_t>> splitCerts;
     for (const auto& cert : certificateChain) {
         splitCerts.push_back(cert.encodedCertificate);
     }
     attestationCertificate_ =
         ::android::hardware::identity::support::certificateChainJoin(splitCerts);

     return Status::ok();
 }

 Status WritableCredential::getCredentialKeyCertificateChain(const vector<uint8_t>& challenge,
                                                             vector<uint8_t>* _aidl_return) {

     Status ensureStatus = ensureAttestationCertificateExists(challenge);
     if (!ensureStatus.isOk()) {
         return ensureStatus;
     }

     *_aidl_return = attestationCertificate_;
     return Status::ok();
 }

 ssize_t WritableCredential::calcExpectedProofOfProvisioningSize(
     const vector<AccessControlProfileParcel>& accessControlProfiles,
     const vector<EntryNamespaceParcel>& entryNamespaces) {

     // Right now, we calculate the size by simply just calculating the
     // CBOR. There's a little bit of overhead associated with this (as compared
     // to just adding up sizes) but it's a lot simpler and robust. In the future
     // if this turns out to be a problem, we can optimize it.
     //

     cppbor::Array acpArray;
     for (const AccessControlProfileParcel& profile : accessControlProfiles) {
         cppbor::Map map;
         map.add("id", profile.id);
         if (profile.readerCertificate.size() > 0) {
             map.add("readerCertificate", cppbor::Bstr(profile.readerCertificate));
         }
         if (profile.userAuthenticationRequired) {
             map.add("userAuthenticationRequired", profile.userAuthenticationRequired);
             map.add("timeoutMillis", profile.userAuthenticationTimeoutMillis);
         }
         acpArray.add(std::move(map));
     }

     cppbor::Map dataMap;
     for (const EntryNamespaceParcel& ensParcel : entryNamespaces) {
         cppbor::Array entriesArray;
         for (const EntryParcel& eParcel : ensParcel.entries) {
             // TODO: ideally do do this without parsing the data (but still validate data is valid
             // CBOR).
             auto [itemForValue, _, _2] = cppbor::parse(eParcel.value);
             if (itemForValue == nullptr) {
                 return -1;
             }
             cppbor::Map entryMap;
             entryMap.add("name", eParcel.name);
             entryMap.add("value", std::move(itemForValue));
             cppbor::Array acpIdsArray;
             for (int32_t id : eParcel.accessControlProfileIds) {
                 acpIdsArray.add(id);
             }
             entryMap.add("accessControlProfiles", std::move(acpIdsArray));
             entriesArray.add(std::move(entryMap));
         }
         dataMap.add(ensParcel.namespaceName, std::move(entriesArray));
     }

     cppbor::Array array;
     array.add("ProofOfProvisioning");
     array.add(docType_);
     array.add(std::move(acpArray));
     array.add(std::move(dataMap));
     array.add(false);  // testCredential
     return array.encode().size();
 }

 Status
 WritableCredential::personalize(const vector<AccessControlProfileParcel>& accessControlProfiles,
                                 const vector<EntryNamespaceParcel>& entryNamespaces,
                                 int64_t secureUserId, vector<uint8_t>* _aidl_return) {
     Status ensureStatus = ensureAttestationCertificateExists({0x00});  // Challenge cannot be empty.
     if (!ensureStatus.isOk()) {
         return ensureStatus;
     }

     uid_t callingUid = android::IPCThreadState::self()->getCallingUid();
     CredentialData data = CredentialData(dataPath_, callingUid, credentialName_);

     // Note: The value 0 is used to convey that no user-authentication is needed for this
     // credential. This is to allow creating credentials w/o user authentication on devices
     // where Secure lock screen is not enabled.
     data.setSecureUserId(secureUserId);

     data.setAttestationCertificate(attestationCertificate_);

     vector<int32_t> entryCounts;
     for (const EntryNamespaceParcel& ensParcel : entryNamespaces) {
         entryCounts.push_back(ensParcel.entries.size());
     }

     ssize_t expectedPoPSize =
         calcExpectedProofOfProvisioningSize(accessControlProfiles, entryNamespaces);
     if (expectedPoPSize < 0) {
         return Status::fromServiceSpecificError(ICredentialStore::ERROR_GENERIC,
                                                 "Data is not valid CBOR");
     }
     // This is not catastrophic, we might be dealing with a version 1 implementation which
     // doesn't have this method.
     Status status = halBinder_->setExpectedProofOfProvisioningSize(expectedPoPSize);
     if (!status.isOk()) {
         LOG(INFO) << "Failed setting expected ProofOfProvisioning size, assuming V1 HAL "
                   << "and continuing";
     }

     status = halBinder_->startPersonalization(accessControlProfiles.size(), entryCounts);
     if (!status.isOk()) {
         return halStatusToGenericError(status);
     }

     for (const AccessControlProfileParcel& acpParcel : accessControlProfiles) {
         Certificate certificate;
         certificate.encodedCertificate = acpParcel.readerCertificate;
         SecureAccessControlProfile profile;
         status = halBinder_->addAccessControlProfile(
             acpParcel.id, certificate, acpParcel.userAuthenticationRequired,
             acpParcel.userAuthenticationTimeoutMillis, secureUserId, &profile);
         if (!status.isOk()) {
             return halStatusToGenericError(status);
         }
         data.addSecureAccessControlProfile(profile);
     }

     for (const EntryNamespaceParcel& ensParcel : entryNamespaces) {
         for (const EntryParcel& eParcel : ensParcel.entries) {
             vector<vector<uint8_t>> chunks = chunkVector(eParcel.value, dataChunkSize_);

             vector<int32_t> ids;
             std::copy(eParcel.accessControlProfileIds.begin(),
                       eParcel.accessControlProfileIds.end(), std::back_inserter(ids));

             status = halBinder_->beginAddEntry(ids, ensParcel.namespaceName, eParcel.name,
                                                eParcel.value.size());
             if (!status.isOk()) {
                 return halStatusToGenericError(status);
             }

             vector<vector<uint8_t>> encryptedChunks;
             for (const auto& chunk : chunks) {
                 vector<uint8_t> encryptedChunk;
                 status = halBinder_->addEntryValue(chunk, &encryptedChunk);
                 if (!status.isOk()) {
                     return halStatusToGenericError(status);
                 }
                 encryptedChunks.push_back(encryptedChunk);
             }
             EntryData eData;
             eData.size = eParcel.value.size();
             eData.accessControlProfileIds = std::move(ids);
             eData.encryptedChunks = std::move(encryptedChunks);
             data.addEntryData(ensParcel.namespaceName, eParcel.name, eData);
         }
     }

     vector<uint8_t> credentialData;
     vector<uint8_t> proofOfProvisioningSignature;
     status = halBinder_->finishAddingEntries(&credentialData, &proofOfProvisioningSignature);
     if (!status.isOk()) {
         return halStatusToGenericError(status);
     }
     data.setCredentialData(credentialData);

     if (!data.saveToDisk()) {
         return Status::fromServiceSpecificError(ICredentialStore::ERROR_GENERIC,
                                                 "Error saving credential data to disk");
     }

     *_aidl_return = proofOfProvisioningSignature;
     return Status::ok();
 }

 }  // namespace identity
 }  // namespace security
 }  // namespace android
	/*
	* Copyright (c) 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 "WritableCredential"

	#include <android-base/logging.h>
	#include <android/hardware/identity/support/IdentityCredentialSupport.h>
	#include <android/security/identity/ICredentialStore.h>
	#include <binder/IPCThreadState.h>
	#include <cppbor.h>
	#include <cppbor_parse.h>
	#include <keystore/keystore_attestation_id.h>

	#include "CredentialData.h"
	#include "Util.h"
	#include "WritableCredential.h"

	namespace android {
	namespace security {
	namespace identity {

	using ::std::pair;

	using ::android::hardware::identity::SecureAccessControlProfile;

	using ::android::hardware::identity::support::chunkVector;

	WritableCredential::WritableCredential(const string& dataPath, const string& credentialName,
	const string& docType, size_t dataChunkSize,
	sp<IWritableIdentityCredential> halBinder)
	: dataPath_(dataPath), credentialName_(credentialName), docType_(docType),
	dataChunkSize_(dataChunkSize), halBinder_(halBinder) {}

	WritableCredential::~WritableCredential() {}

	Status WritableCredential::ensureAttestationCertificateExists(const vector<uint8_t>& challenge) {
	if (!attestationCertificate_.empty()) {
	return Status::ok();
	}

	const int32_t callingUid = IPCThreadState::self()->getCallingUid();
	auto asn1AttestationId = android::security::gather_attestation_application_id(callingUid);
	if (!asn1AttestationId.isOk()) {
	LOG(ERROR) << "Failed gathering AttestionApplicationId";
	return Status::fromServiceSpecificError(ICredentialStore::ERROR_GENERIC,
	"Failed gathering AttestionApplicationId");
	}

	vector<Certificate> certificateChain;
	Status status = halBinder_->getAttestationCertificate(asn1AttestationId.value(), challenge,
	&certificateChain);
	if (!status.isOk()) {
	LOG(ERROR) << "Error calling getAttestationCertificate()";
	return halStatusToGenericError(status);
	}

	vector<vector<uint8_t>> splitCerts;
	for (const auto& cert : certificateChain) {
	splitCerts.push_back(cert.encodedCertificate);
	}
	attestationCertificate_ =
	::android::hardware::identity::support::certificateChainJoin(splitCerts);

	return Status::ok();
	}

	Status WritableCredential::getCredentialKeyCertificateChain(const vector<uint8_t>& challenge,
	vector<uint8_t>* _aidl_return) {

	Status ensureStatus = ensureAttestationCertificateExists(challenge);
	if (!ensureStatus.isOk()) {
	return ensureStatus;
	}

	*_aidl_return = attestationCertificate_;
	return Status::ok();
	}

	ssize_t WritableCredential::calcExpectedProofOfProvisioningSize(
	const vector<AccessControlProfileParcel>& accessControlProfiles,
	const vector<EntryNamespaceParcel>& entryNamespaces) {

	// Right now, we calculate the size by simply just calculating the
	// CBOR. There's a little bit of overhead associated with this (as compared
	// to just adding up sizes) but it's a lot simpler and robust. In the future
	// if this turns out to be a problem, we can optimize it.
	//

	cppbor::Array acpArray;
	for (const AccessControlProfileParcel& profile : accessControlProfiles) {
	cppbor::Map map;
	map.add("id", profile.id);
	if (profile.readerCertificate.size() > 0) {
	map.add("readerCertificate", cppbor::Bstr(profile.readerCertificate));
	}
	if (profile.userAuthenticationRequired) {
	map.add("userAuthenticationRequired", profile.userAuthenticationRequired);
	map.add("timeoutMillis", profile.userAuthenticationTimeoutMillis);
	}
	acpArray.add(std::move(map));
	}

	cppbor::Map dataMap;
	for (const EntryNamespaceParcel& ensParcel : entryNamespaces) {
	cppbor::Array entriesArray;
	for (const EntryParcel& eParcel : ensParcel.entries) {
	// TODO: ideally do do this without parsing the data (but still validate data is valid
	// CBOR).
	auto [itemForValue, _, _2] = cppbor::parse(eParcel.value);
	if (itemForValue == nullptr) {
	return -1;
	}
	cppbor::Map entryMap;
	entryMap.add("name", eParcel.name);
	entryMap.add("value", std::move(itemForValue));
	cppbor::Array acpIdsArray;
	for (int32_t id : eParcel.accessControlProfileIds) {
	acpIdsArray.add(id);
	}
	entryMap.add("accessControlProfiles", std::move(acpIdsArray));
	entriesArray.add(std::move(entryMap));
	}
	dataMap.add(ensParcel.namespaceName, std::move(entriesArray));
	}

	cppbor::Array array;
	array.add("ProofOfProvisioning");
	array.add(docType_);
	array.add(std::move(acpArray));
	array.add(std::move(dataMap));
	array.add(false); // testCredential
	return array.encode().size();
	}

	Status
	WritableCredential::personalize(const vector<AccessControlProfileParcel>& accessControlProfiles,
	const vector<EntryNamespaceParcel>& entryNamespaces,
	int64_t secureUserId, vector<uint8_t>* _aidl_return) {
	Status ensureStatus = ensureAttestationCertificateExists({0x00}); // Challenge cannot be empty.
	if (!ensureStatus.isOk()) {
	return ensureStatus;
	}

	uid_t callingUid = android::IPCThreadState::self()->getCallingUid();
	CredentialData data = CredentialData(dataPath_, callingUid, credentialName_);

	// Note: The value 0 is used to convey that no user-authentication is needed for this
	// credential. This is to allow creating credentials w/o user authentication on devices
	// where Secure lock screen is not enabled.
	data.setSecureUserId(secureUserId);

	data.setAttestationCertificate(attestationCertificate_);

	vector<int32_t> entryCounts;
	for (const EntryNamespaceParcel& ensParcel : entryNamespaces) {
	entryCounts.push_back(ensParcel.entries.size());
	}

	ssize_t expectedPoPSize =
	calcExpectedProofOfProvisioningSize(accessControlProfiles, entryNamespaces);
	if (expectedPoPSize < 0) {
	return Status::fromServiceSpecificError(ICredentialStore::ERROR_GENERIC,
	"Data is not valid CBOR");
	}
	// This is not catastrophic, we might be dealing with a version 1 implementation which
	// doesn't have this method.
	Status status = halBinder_->setExpectedProofOfProvisioningSize(expectedPoPSize);
	if (!status.isOk()) {
	LOG(INFO) << "Failed setting expected ProofOfProvisioning size, assuming V1 HAL "
	<< "and continuing";
	}

	status = halBinder_->startPersonalization(accessControlProfiles.size(), entryCounts);
	if (!status.isOk()) {
	return halStatusToGenericError(status);
	}

	for (const AccessControlProfileParcel& acpParcel : accessControlProfiles) {
	Certificate certificate;
	certificate.encodedCertificate = acpParcel.readerCertificate;
	SecureAccessControlProfile profile;
	status = halBinder_->addAccessControlProfile(
	acpParcel.id, certificate, acpParcel.userAuthenticationRequired,
	acpParcel.userAuthenticationTimeoutMillis, secureUserId, &profile);
	if (!status.isOk()) {
	return halStatusToGenericError(status);
	}
	data.addSecureAccessControlProfile(profile);
	}

	for (const EntryNamespaceParcel& ensParcel : entryNamespaces) {
	for (const EntryParcel& eParcel : ensParcel.entries) {
	vector<vector<uint8_t>> chunks = chunkVector(eParcel.value, dataChunkSize_);

	vector<int32_t> ids;
	std::copy(eParcel.accessControlProfileIds.begin(),
	eParcel.accessControlProfileIds.end(), std::back_inserter(ids));

	status = halBinder_->beginAddEntry(ids, ensParcel.namespaceName, eParcel.name,
	eParcel.value.size());
	if (!status.isOk()) {
	return halStatusToGenericError(status);
	}

	vector<vector<uint8_t>> encryptedChunks;
	for (const auto& chunk : chunks) {
	vector<uint8_t> encryptedChunk;
	status = halBinder_->addEntryValue(chunk, &encryptedChunk);
	if (!status.isOk()) {
	return halStatusToGenericError(status);
	}
	encryptedChunks.push_back(encryptedChunk);
	}
	EntryData eData;
	eData.size = eParcel.value.size();
	eData.accessControlProfileIds = std::move(ids);
	eData.encryptedChunks = std::move(encryptedChunks);
	data.addEntryData(ensParcel.namespaceName, eParcel.name, eData);
	}
	}

	vector<uint8_t> credentialData;
	vector<uint8_t> proofOfProvisioningSignature;
	status = halBinder_->finishAddingEntries(&credentialData, &proofOfProvisioningSignature);
	if (!status.isOk()) {
	return halStatusToGenericError(status);
	}
	data.setCredentialData(credentialData);

	if (!data.saveToDisk()) {
	return Status::fromServiceSpecificError(ICredentialStore::ERROR_GENERIC,
	"Error saving credential data to disk");
	}

	*_aidl_return = proofOfProvisioningSignature;
	return Status::ok();
	}

	} // namespace identity
	} // namespace security
	} // namespace android