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

1 files changed, 324 insertions, 0 deletions

diff --git a/identity/aidl/default/FakeSecureHardwareProxy.cpp b/identity/aidl/default/FakeSecureHardwareProxy.cpp
new file mode 100644
index 0000000000..de6762fc2e
--- /dev/null
+++ b/identity/aidl/default/FakeSecureHardwareProxy.cpp
@@ -0,0 +1,324 @@
+/*
+ * Copyright 2020, 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 "FakeSecureHardwareProxy"
+
+#include "FakeSecureHardwareProxy.h"
+
+#include <android/hardware/identity/support/IdentityCredentialSupport.h>
+
+#include <android-base/logging.h>
+#include <android-base/stringprintf.h>
+#include <string.h>
+
+#include <openssl/sha.h>
+
+#include <openssl/aes.h>
+#include <openssl/bn.h>
+#include <openssl/crypto.h>
+#include <openssl/ec.h>
+#include <openssl/err.h>
+#include <openssl/evp.h>
+#include <openssl/hkdf.h>
+#include <openssl/hmac.h>
+#include <openssl/objects.h>
+#include <openssl/pem.h>
+#include <openssl/pkcs12.h>
+#include <openssl/rand.h>
+#include <openssl/x509.h>
+#include <openssl/x509_vfy.h>
+
+#include <libeic.h>
+
+using ::std::optional;
+using ::std::string;
+using ::std::tuple;
+using ::std::vector;
+
+namespace android::hardware::identity {
+
+// ----------------------------------------------------------------------
+
+FakeSecureHardwareProvisioningProxy::FakeSecureHardwareProvisioningProxy() {}
+
+FakeSecureHardwareProvisioningProxy::~FakeSecureHardwareProvisioningProxy() {}
+
+bool FakeSecureHardwareProvisioningProxy::shutdown() {
+    LOG(INFO) << "FakeSecureHardwarePresentationProxy shutdown";
+    return true;
+}
+
+bool FakeSecureHardwareProvisioningProxy::initialize(bool testCredential) {
+    LOG(INFO) << "FakeSecureHardwareProvisioningProxy created, sizeof(EicProvisioning): "
+              << sizeof(EicProvisioning);
+    return eicProvisioningInit(&ctx_, testCredential);
+}
+
+// Returns public key certificate.
+optional<vector<uint8_t>> FakeSecureHardwareProvisioningProxy::createCredentialKey(
+        const vector<uint8_t>& challenge, const vector<uint8_t>& applicationId) {
+    uint8_t publicKeyCert[4096];
+    size_t publicKeyCertSize = sizeof publicKeyCert;
+    if (!eicProvisioningCreateCredentialKey(&ctx_, challenge.data(), challenge.size(),
+                                            applicationId.data(), applicationId.size(),
+                                            publicKeyCert, &publicKeyCertSize)) {
+        return {};
+    }
+    vector<uint8_t> pubKeyCert(publicKeyCertSize);
+    memcpy(pubKeyCert.data(), publicKeyCert, publicKeyCertSize);
+    return pubKeyCert;
+}
+
+bool FakeSecureHardwareProvisioningProxy::startPersonalization(
+        int accessControlProfileCount, vector<int> entryCounts, const string& docType,
+        size_t expectedProofOfProvisioningSize) {
+    if (!eicProvisioningStartPersonalization(&ctx_, accessControlProfileCount, entryCounts.data(),
+                                             entryCounts.size(), docType.c_str(),
+                                             expectedProofOfProvisioningSize)) {
+        return false;
+    }
+    return true;
+}
+
+// Returns MAC (28 bytes).
+optional<vector<uint8_t>> FakeSecureHardwareProvisioningProxy::addAccessControlProfile(
+        int id, const vector<uint8_t>& readerCertificate, bool userAuthenticationRequired,
+        uint64_t timeoutMillis, uint64_t secureUserId) {
+    vector<uint8_t> mac(28);
+    if (!eicProvisioningAddAccessControlProfile(
+                &ctx_, id, readerCertificate.data(), readerCertificate.size(),
+                userAuthenticationRequired, timeoutMillis, secureUserId, mac.data())) {
+        return {};
+    }
+    return mac;
+}
+
+bool FakeSecureHardwareProvisioningProxy::beginAddEntry(const vector<int>& accessControlProfileIds,
+                                                        const string& nameSpace, const string& name,
+                                                        uint64_t entrySize) {
+    uint8_t scratchSpace[512];
+    return eicProvisioningBeginAddEntry(&ctx_, accessControlProfileIds.data(),
+                                        accessControlProfileIds.size(), nameSpace.c_str(),
+                                        name.c_str(), entrySize, scratchSpace, sizeof scratchSpace);
+}
+
+// Returns encryptedContent.
+optional<vector<uint8_t>> FakeSecureHardwareProvisioningProxy::addEntryValue(
+        const vector<int>& accessControlProfileIds, const string& nameSpace, const string& name,
+        const vector<uint8_t>& content) {
+    vector<uint8_t> eicEncryptedContent;
+    uint8_t scratchSpace[512];
+    eicEncryptedContent.resize(content.size() + 28);
+    if (!eicProvisioningAddEntryValue(
+                &ctx_, accessControlProfileIds.data(), accessControlProfileIds.size(),
+                nameSpace.c_str(), name.c_str(), content.data(), content.size(),
+                eicEncryptedContent.data(), scratchSpace, sizeof scratchSpace)) {
+        return {};
+    }
+    return eicEncryptedContent;
+}
+
+// Returns signatureOfToBeSigned (EIC_ECDSA_P256_SIGNATURE_SIZE bytes).
+optional<vector<uint8_t>> FakeSecureHardwareProvisioningProxy::finishAddingEntries() {
+    vector<uint8_t> signatureOfToBeSigned(EIC_ECDSA_P256_SIGNATURE_SIZE);
+    if (!eicProvisioningFinishAddingEntries(&ctx_, signatureOfToBeSigned.data())) {
+        return {};
+    }
+    return signatureOfToBeSigned;
+}
+
+// Returns encryptedCredentialKeys (80 bytes).
+optional<vector<uint8_t>> FakeSecureHardwareProvisioningProxy::finishGetCredentialData(
+        const string& docType) {
+    vector<uint8_t> encryptedCredentialKeys(80);
+    if (!eicProvisioningFinishGetCredentialData(&ctx_, docType.c_str(),
+                                                encryptedCredentialKeys.data())) {
+        return {};
+    }
+    return encryptedCredentialKeys;
+}
+
+// ----------------------------------------------------------------------
+
+FakeSecureHardwarePresentationProxy::FakeSecureHardwarePresentationProxy() {}
+
+FakeSecureHardwarePresentationProxy::~FakeSecureHardwarePresentationProxy() {}
+
+bool FakeSecureHardwarePresentationProxy::initialize(bool testCredential, string docType,
+                                                     vector<uint8_t> encryptedCredentialKeys) {
+    LOG(INFO) << "FakeSecureHardwarePresentationProxy created, sizeof(EicPresentation): "
+              << sizeof(EicPresentation);
+    return eicPresentationInit(&ctx_, testCredential, docType.c_str(),
+                               encryptedCredentialKeys.data());
+}
+
+// Returns publicKeyCert (1st component) and signingKeyBlob (2nd component)
+optional<pair<vector<uint8_t>, vector<uint8_t>>>
+FakeSecureHardwarePresentationProxy::generateSigningKeyPair(string docType, time_t now) {
+    uint8_t publicKeyCert[512];
+    size_t publicKeyCertSize = sizeof(publicKeyCert);
+    vector<uint8_t> signingKeyBlob(60);
+
+    if (!eicPresentationGenerateSigningKeyPair(&ctx_, docType.c_str(), now, publicKeyCert,
+                                               &publicKeyCertSize, signingKeyBlob.data())) {
+        return {};
+    }
+
+    vector<uint8_t> cert;
+    cert.resize(publicKeyCertSize);
+    memcpy(cert.data(), publicKeyCert, publicKeyCertSize);
+
+    return std::make_pair(cert, signingKeyBlob);
+}
+
+// Returns private key
+optional<vector<uint8_t>> FakeSecureHardwarePresentationProxy::createEphemeralKeyPair() {
+    vector<uint8_t> priv(EIC_P256_PRIV_KEY_SIZE);
+    if (!eicPresentationCreateEphemeralKeyPair(&ctx_, priv.data())) {
+        return {};
+    }
+    return priv;
+}
+
+optional<uint64_t> FakeSecureHardwarePresentationProxy::createAuthChallenge() {
+    uint64_t challenge;
+    if (!eicPresentationCreateAuthChallenge(&ctx_, &challenge)) {
+        return {};
+    }
+    return challenge;
+}
+
+bool FakeSecureHardwarePresentationProxy::shutdown() {
+    LOG(INFO) << "FakeSecureHardwarePresentationProxy shutdown";
+    return true;
+}
+
+bool FakeSecureHardwarePresentationProxy::pushReaderCert(const vector<uint8_t>& certX509) {
+    return eicPresentationPushReaderCert(&ctx_, certX509.data(), certX509.size());
+}
+
+bool FakeSecureHardwarePresentationProxy::validateRequestMessage(
+        const vector<uint8_t>& sessionTranscript, const vector<uint8_t>& requestMessage,
+        int coseSignAlg, const vector<uint8_t>& readerSignatureOfToBeSigned) {
+    return eicPresentationValidateRequestMessage(
+            &ctx_, sessionTranscript.data(), sessionTranscript.size(), requestMessage.data(),
+            requestMessage.size(), coseSignAlg, readerSignatureOfToBeSigned.data(),
+            readerSignatureOfToBeSigned.size());
+}
+
+bool FakeSecureHardwarePresentationProxy::setAuthToken(
+        uint64_t challenge, uint64_t secureUserId, uint64_t authenticatorId,
+        int hardwareAuthenticatorType, uint64_t timeStamp, const vector<uint8_t>& mac,
+        uint64_t verificationTokenChallenge, uint64_t verificationTokenTimestamp,
+        int verificationTokenSecurityLevel, const vector<uint8_t>& verificationTokenMac) {
+    return eicPresentationSetAuthToken(&ctx_, challenge, secureUserId, authenticatorId,
+                                       hardwareAuthenticatorType, timeStamp, mac.data(), mac.size(),
+                                       verificationTokenChallenge, verificationTokenTimestamp,
+                                       verificationTokenSecurityLevel, verificationTokenMac.data(),
+                                       verificationTokenMac.size());
+}
+
+optional<bool> FakeSecureHardwarePresentationProxy::validateAccessControlProfile(
+        int id, const vector<uint8_t>& readerCertificate, bool userAuthenticationRequired,
+        int timeoutMillis, uint64_t secureUserId, const vector<uint8_t>& mac) {
+    bool accessGranted = false;
+    if (!eicPresentationValidateAccessControlProfile(&ctx_, id, readerCertificate.data(),
+                                                     readerCertificate.size(),
+                                                     userAuthenticationRequired, timeoutMillis,
+                                                     secureUserId, mac.data(), &accessGranted)) {
+        return {};
+    }
+    return accessGranted;
+}
+
+bool FakeSecureHardwarePresentationProxy::startRetrieveEntries() {
+    return eicPresentationStartRetrieveEntries(&ctx_);
+}
+
+bool FakeSecureHardwarePresentationProxy::calcMacKey(
+        const vector<uint8_t>& sessionTranscript, const vector<uint8_t>& readerEphemeralPublicKey,
+        const vector<uint8_t>& signingKeyBlob, const string& docType,
+        unsigned int numNamespacesWithValues, size_t expectedProofOfProvisioningSize) {
+    if (signingKeyBlob.size() != 60) {
+        eicDebug("Unexpected size %zd of signingKeyBlob, expected 60", signingKeyBlob.size());
+        return false;
+    }
+    return eicPresentationCalcMacKey(&ctx_, sessionTranscript.data(), sessionTranscript.size(),
+                                     readerEphemeralPublicKey.data(), signingKeyBlob.data(),
+                                     docType.c_str(), numNamespacesWithValues,
+                                     expectedProofOfProvisioningSize);
+}
+
+AccessCheckResult FakeSecureHardwarePresentationProxy::startRetrieveEntryValue(
+        const string& nameSpace, const string& name, unsigned int newNamespaceNumEntries,
+        int32_t entrySize, const vector<int32_t>& accessControlProfileIds) {
+    uint8_t scratchSpace[512];
+    EicAccessCheckResult result = eicPresentationStartRetrieveEntryValue(
+            &ctx_, nameSpace.c_str(), name.c_str(), newNamespaceNumEntries, entrySize,
+            accessControlProfileIds.data(), accessControlProfileIds.size(), scratchSpace,
+            sizeof scratchSpace);
+    switch (result) {
+        case EIC_ACCESS_CHECK_RESULT_OK:
+            return AccessCheckResult::kOk;
+        case EIC_ACCESS_CHECK_RESULT_NO_ACCESS_CONTROL_PROFILES:
+            return AccessCheckResult::kNoAccessControlProfiles;
+        case EIC_ACCESS_CHECK_RESULT_FAILED:
+            return AccessCheckResult::kFailed;
+        case EIC_ACCESS_CHECK_RESULT_USER_AUTHENTICATION_FAILED:
+            return AccessCheckResult::kUserAuthenticationFailed;
+        case EIC_ACCESS_CHECK_RESULT_READER_AUTHENTICATION_FAILED:
+            return AccessCheckResult::kReaderAuthenticationFailed;
+    }
+    eicDebug("Unknown result with code %d, returning kFailed", (int)result);
+    return AccessCheckResult::kFailed;
+}
+
+optional<vector<uint8_t>> FakeSecureHardwarePresentationProxy::retrieveEntryValue(
+        const vector<uint8_t>& encryptedContent, const string& nameSpace, const string& name,
+        const vector<int32_t>& accessControlProfileIds) {
+    uint8_t scratchSpace[512];
+    vector<uint8_t> content;
+    content.resize(encryptedContent.size() - 28);
+    if (!eicPresentationRetrieveEntryValue(
+                &ctx_, encryptedContent.data(), encryptedContent.size(), content.data(),
+                nameSpace.c_str(), name.c_str(), accessControlProfileIds.data(),
+                accessControlProfileIds.size(), scratchSpace, sizeof scratchSpace)) {
+        return {};
+    }
+    return content;
+}
+
+optional<vector<uint8_t>> FakeSecureHardwarePresentationProxy::finishRetrieval() {
+    vector<uint8_t> mac(32);
+    size_t macSize = 32;
+    if (!eicPresentationFinishRetrieval(&ctx_, mac.data(), &macSize)) {
+        return {};
+    }
+    mac.resize(macSize);
+    return mac;
+}
+
+optional<vector<uint8_t>> FakeSecureHardwarePresentationProxy::deleteCredential(
+        const string& docType, size_t proofOfDeletionCborSize) {
+    vector<uint8_t> signatureOfToBeSigned(EIC_ECDSA_P256_SIGNATURE_SIZE);
+    if (!eicPresentationDeleteCredential(&ctx_, docType.c_str(), proofOfDeletionCborSize,
+                                         signatureOfToBeSigned.data())) {
+        return {};
+    }
+    return signatureOfToBeSigned;
+}
+
+}  // namespace android::hardware::identity