keystore: Pass verification token to credstore along with requested auth token.
This is needed because the Secure Areas backing the Identity
Credential HAL may exist in a different environment from where the
auth token is minted. In this case, the Secure Area needs a
verification token to make sense of the timestamp in the auth token.
Getting a verification token is an asynchronous operation so change
the binder method used by credstore to be asynchronous as well.
Bug: 156076333
Test: atest VtsHalIdentityTargetTest
Test: atest android.security.identity.cts
Change-Id: Id6cb6812a31d968069b7d72bd2b39b512d38d241
diff --git a/identity/Credential.cpp b/identity/Credential.cpp
index 49b412f..59a4d81 100644
--- a/identity/Credential.cpp
+++ b/identity/Credential.cpp
@@ -22,6 +22,7 @@
#include <android/security/identity/ICredentialStore.h>
+#include <android/security/keystore/BnCredstoreTokenCallback.h>
#include <android/security/keystore/IKeystoreService.h>
#include <binder/IPCThreadState.h>
#include <binder/IServiceManager.h>
@@ -29,6 +30,8 @@
#include <cppbor.h>
#include <cppbor_parse.h>
+#include <future>
+#include <tuple>
#include "Credential.h"
#include "CredentialData.h"
@@ -39,6 +42,8 @@
namespace identity {
using std::optional;
+using std::promise;
+using std::tuple;
using android::security::keystore::IKeystoreService;
@@ -48,7 +53,9 @@
using ::android::hardware::identity::support::sha256;
using android::hardware::keymaster::V4_0::HardwareAuthToken;
+using android::hardware::keymaster::V4_0::VerificationToken;
using AidlHardwareAuthToken = android::hardware::keymaster::HardwareAuthToken;
+using AidlVerificationToken = android::hardware::keymaster::VerificationToken;
Credential::Credential(CipherSuite cipherSuite, const std::string& dataPath,
const std::string& credentialName)
@@ -116,12 +123,22 @@
return Status::ok();
}
+class CredstoreTokenCallback : public android::security::keystore::BnCredstoreTokenCallback,
+ public promise<tuple<bool, vector<uint8_t>, vector<uint8_t>>> {
+ public:
+ CredstoreTokenCallback() {}
+ virtual Status onFinished(bool success, const vector<uint8_t>& authToken,
+ const vector<uint8_t>& verificationToken) override {
+ this->set_value({success, authToken, verificationToken});
+ return Status::ok();
+ }
+};
+
// Returns false if an error occurred communicating with keystore.
//
-// Sets |authToken| to the empty vector if an auth token couldn't be obtained.
-//
-bool getAuthTokenFromKeystore(uint64_t challenge, uint64_t secureUserId,
- unsigned int authTokenMaxAgeMillis, vector<uint8_t>& authToken) {
+bool getTokensFromKeystore(uint64_t challenge, uint64_t secureUserId,
+ unsigned int authTokenMaxAgeMillis, vector<uint8_t>& authToken,
+ vector<uint8_t>& verificationToken) {
sp<IServiceManager> sm = defaultServiceManager();
sp<IBinder> binder = sm->getService(String16("android.security.keystore"));
sp<IKeystoreService> keystore = interface_cast<IKeystoreService>(binder);
@@ -129,13 +146,27 @@
return false;
}
- vector<uint8_t> returnedAuthToken;
- Status ret = keystore->getAuthTokenForCredstore(challenge, secureUserId, authTokenMaxAgeMillis,
- &returnedAuthToken);
- if (!ret.isOk()) {
+ sp<CredstoreTokenCallback> callback = new CredstoreTokenCallback();
+ auto future = callback->get_future();
+
+ Status status =
+ keystore->getTokensForCredstore(challenge, secureUserId, authTokenMaxAgeMillis, callback);
+ if (!status.isOk()) {
+ return false;
+ }
+
+ auto fstatus = future.wait_for(std::chrono::milliseconds(5000));
+ if (fstatus != std::future_status::ready) {
+ LOG(ERROR) << "Waited 5 seconds from tokens for credstore, aborting";
+ return false;
+ }
+ auto [success, returnedAuthToken, returnedVerificationToken] = future.get();
+ if (!success) {
+ LOG(ERROR) << "Error getting tokens from credstore";
return false;
}
authToken = returnedAuthToken;
+ verificationToken = returnedVerificationToken;
return true;
}
@@ -217,16 +248,37 @@
authTokenMaxAgeMillis = 10 * 1000;
}
- // Only get an authToken if it's actually needed.
+ // Reset tokens and only get them if they're actually needed, e.g. if user authentication
+ // is needed in any of the access control profiles for data items being requested.
+ //
AidlHardwareAuthToken aidlAuthToken;
+ AidlVerificationToken aidlVerificationToken;
+ aidlAuthToken.challenge = 0;
+ aidlAuthToken.userId = 0;
+ aidlAuthToken.authenticatorId = 0;
+ aidlAuthToken.authenticatorType =
+ ::android::hardware::keymaster::HardwareAuthenticatorType::NONE;
+ aidlAuthToken.timestamp.milliSeconds = 0;
+ aidlAuthToken.mac.clear();
+ aidlVerificationToken.challenge = 0;
+ aidlVerificationToken.timestamp.milliSeconds = 0;
+ aidlVerificationToken.securityLevel = ::android::hardware::keymaster::SecurityLevel::SOFTWARE;
+ aidlVerificationToken.mac.clear();
if (userAuthNeeded) {
vector<uint8_t> authTokenBytes;
- if (!getAuthTokenFromKeystore(selectedChallenge_, data_->getSecureUserId(),
- authTokenMaxAgeMillis, authTokenBytes)) {
- LOG(ERROR) << "Error getting auth token from keystore";
+ vector<uint8_t> verificationTokenBytes;
+ if (!getTokensFromKeystore(selectedChallenge_, data_->getSecureUserId(),
+ authTokenMaxAgeMillis, authTokenBytes, verificationTokenBytes)) {
+ LOG(ERROR) << "Error getting tokens from keystore";
return Status::fromServiceSpecificError(ICredentialStore::ERROR_GENERIC,
- "Error getting auth token from keystore");
+ "Error getting tokens from keystore");
}
+
+ // It's entirely possible getTokensFromKeystore() succeeded but didn't
+ // return any tokens (in which case the returned byte-vectors are
+ // empty). For example, this can happen if no auth token is available
+ // which satifies e.g. |authTokenMaxAgeMillis|.
+ //
if (authTokenBytes.size() > 0) {
HardwareAuthToken authToken =
android::hardware::keymaster::V4_0::support::hidlVec2AuthToken(authTokenBytes);
@@ -240,6 +292,22 @@
aidlAuthToken.timestamp.milliSeconds = int64_t(authToken.timestamp);
aidlAuthToken.mac = authToken.mac;
}
+
+ if (verificationTokenBytes.size() > 0) {
+ optional<VerificationToken> token =
+ android::hardware::keymaster::V4_0::support::deserializeVerificationToken(
+ verificationTokenBytes);
+ if (!token) {
+ LOG(ERROR) << "Error deserializing verification token";
+ return Status::fromServiceSpecificError(ICredentialStore::ERROR_GENERIC,
+ "Error deserializing verification token");
+ }
+ aidlVerificationToken.challenge = token->challenge;
+ aidlVerificationToken.timestamp.milliSeconds = token->timestamp;
+ aidlVerificationToken.securityLevel =
+ ::android::hardware::keymaster::SecurityLevel(token->securityLevel);
+ aidlVerificationToken.mac = token->mac;
+ }
}
// Note that the selectAuthKey() method is only called if a CryptoObject is involved at
@@ -285,7 +353,14 @@
// doesn't have this method.
Status status = halBinder_->setRequestedNamespaces(halRequestNamespaces);
if (!status.isOk()) {
- LOG(INFO) << "Failed setting expected requested namespaces assuming V1 HAL "
+ LOG(INFO) << "Failed setting expected requested namespaces, assuming V1 HAL "
+ << "and continuing";
+ }
+
+ // Pass the verification token. Failure is OK, this method isn't in the V1 HAL.
+ status = halBinder_->setVerificationToken(aidlVerificationToken);
+ if (!status.isOk()) {
+ LOG(INFO) << "Failed setting verification token, assuming V1 HAL "
<< "and continuing";
}
diff --git a/identity/main.cpp b/identity/main.cpp
index af03a30..8f4968d 100644
--- a/identity/main.cpp
+++ b/identity/main.cpp
@@ -53,6 +53,9 @@
CHECK(ret == ::android::OK) << "Couldn't register binder service";
LOG(ERROR) << "Registered binder service";
+ // This is needed for binder callbacks from keystore on a ICredstoreTokenCallback binder.
+ android::ProcessState::self()->startThreadPool();
+
IPCThreadState::self()->joinThreadPool();
return 0;
diff --git a/keystore/Android.bp b/keystore/Android.bp
index 6145047..b881757 100644
--- a/keystore/Android.bp
+++ b/keystore/Android.bp
@@ -294,6 +294,7 @@
name: "keystore_aidl",
srcs: [
"binder/android/security/IConfirmationPromptCallback.aidl",
+ "binder/android/security/keystore/ICredstoreTokenCallback.aidl",
"binder/android/security/keystore/IKeystoreCertificateChainCallback.aidl",
"binder/android/security/keystore/IKeystoreExportKeyCallback.aidl",
"binder/android/security/keystore/IKeystoreKeyCharacteristicsCallback.aidl",
diff --git a/keystore/binder/android/security/keystore/ICredstoreTokenCallback.aidl b/keystore/binder/android/security/keystore/ICredstoreTokenCallback.aidl
new file mode 100644
index 0000000..b42e3d4
--- /dev/null
+++ b/keystore/binder/android/security/keystore/ICredstoreTokenCallback.aidl
@@ -0,0 +1,25 @@
+/**
+ * Copyright (c) 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.
+ */
+
+package android.security.keystore;
+
+
+/**
+ * @hide
+ */
+oneway interface ICredstoreTokenCallback {
+ void onFinished(boolean success, in byte[] authToken, in byte[] verificationToken);
+}
diff --git a/keystore/binder/android/security/keystore/IKeystoreService.aidl b/keystore/binder/android/security/keystore/IKeystoreService.aidl
index fcea115..6edca56 100644
--- a/keystore/binder/android/security/keystore/IKeystoreService.aidl
+++ b/keystore/binder/android/security/keystore/IKeystoreService.aidl
@@ -19,6 +19,7 @@
import android.security.keymaster.KeymasterArguments;
import android.security.keymaster.KeymasterBlob;
import android.security.keymaster.OperationResult;
+import android.security.keystore.ICredstoreTokenCallback;
import android.security.keystore.IKeystoreResponseCallback;
import android.security.keystore.IKeystoreKeyCharacteristicsCallback;
import android.security.keystore.IKeystoreExportKeyCallback;
@@ -86,5 +87,6 @@
int listUidsOfAuthBoundKeys(out @utf8InCpp List<String> uids);
// Called by credstore (and only credstore).
- byte[] getAuthTokenForCredstore(in long challenge, in long secureUserId, in int authTokenMaxAgeMillis);
+ void getTokensForCredstore(in long challenge, in long secureUserId, in int authTokenMaxAgeMillis,
+ in ICredstoreTokenCallback cb);
}
diff --git a/keystore/key_store_service.cpp b/keystore/key_store_service.cpp
index fc85616..583f5b6 100644
--- a/keystore/key_store_service.cpp
+++ b/keystore/key_store_service.cpp
@@ -57,6 +57,8 @@
namespace {
using ::android::binder::Status;
+using android::hardware::keymaster::V4_0::support::authToken2HidlVec;
+using android::hardware::keymaster::V4_0::support::serializeVerificationToken;
using android::security::keymaster::ExportResult;
using android::security::keymaster::KeymasterArguments;
using android::security::keymaster::KeymasterBlob;
@@ -64,6 +66,7 @@
using android::security::keymaster::operationFailed;
using android::security::keymaster::OperationResult;
using ConfirmationResponseCode = android::hardware::confirmationui::V1_0::ResponseCode;
+using ::android::security::keystore::ICredstoreTokenCallback;
using ::android::security::keystore::IKeystoreOperationResultCallback;
using ::android::security::keystore::IKeystoreResponseCallback;
using ::android::security::keystore::KeystoreResponse;
@@ -943,9 +946,9 @@
return Status::ok();
}
-Status KeyStoreService::getAuthTokenForCredstore(int64_t challenge, int64_t secureUserId,
- int32_t authTokenMaxAgeMillis,
- std::vector<uint8_t>* _aidl_return) {
+Status KeyStoreService::getTokensForCredstore(int64_t challenge, int64_t secureUserId,
+ int32_t authTokenMaxAgeMillis,
+ const ::android::sp<ICredstoreTokenCallback>& cb) {
uid_t callingUid = IPCThreadState::self()->getCallingUid();
if (callingUid != AID_CREDSTORE) {
return Status::fromServiceSpecificError(static_cast<int32_t>(0));
@@ -953,11 +956,48 @@
auto [err, authToken] = mKeyStore->getAuthTokenTable().FindAuthorizationForCredstore(
challenge, secureUserId, authTokenMaxAgeMillis);
- std::vector<uint8_t> ret;
- if (err == AuthTokenTable::OK) {
- ret = android::hardware::keymaster::V4_0::support::authToken2HidlVec(authToken);
+ // It's entirely possible we couldn't find an authToken (e.g. no user auth
+ // happened within the requested deadline) and in that case, we just
+ // callback immediately signaling success but just not returning any tokens.
+ if (err != AuthTokenTable::OK) {
+ cb->onFinished(true, {} /* serializedAuthToken */, {} /* serializedVerificationToken */);
+ return Status::ok();
}
- *_aidl_return = ret;
+
+ // If we did find an authToken, get a verificationToken as well...
+ //
+ std::vector<uint8_t> serializedAuthToken = authToken2HidlVec(authToken);
+ std::vector<uint8_t> serializedVerificationToken;
+ std::shared_ptr<KeymasterWorker> dev = mKeyStore->getDevice(SecurityLevel::TRUSTED_ENVIRONMENT);
+ if (!dev) {
+ LOG(ERROR) << "Unable to get KM device for SecurityLevel::TRUSTED_ENVIRONMENT";
+ dev = mKeyStore->getDevice(SecurityLevel::SOFTWARE);
+ if (!dev) {
+ LOG(ERROR) << "Unable to get KM device for SecurityLevel::SOFTWARE";
+ cb->onFinished(false, {}, {});
+ return Status::fromServiceSpecificError(static_cast<int32_t>(0));
+ }
+ }
+
+ dev->verifyAuthorization(
+ challenge, {} /* params */, authToken,
+ [serializedAuthToken, cb](KeyStoreServiceReturnCode rc, HardwareAuthToken,
+ VerificationToken verificationToken) {
+ if (rc != ErrorCode::OK) {
+ LOG(ERROR) << "verifyAuthorization failed, rc=" << rc;
+ cb->onFinished(false, {}, {});
+ return;
+ }
+ std::optional<std::vector<uint8_t>> serializedVerificationToken =
+ serializeVerificationToken(verificationToken);
+ if (!serializedVerificationToken) {
+ LOG(ERROR) << "Error serializing verificationToken";
+ cb->onFinished(false, {}, {});
+ return;
+ }
+ cb->onFinished(true, serializedAuthToken, serializedVerificationToken.value());
+ });
+
return Status::ok();
}
diff --git a/keystore/key_store_service.h b/keystore/key_store_service.h
index 8c1d508..5fdddb9 100644
--- a/keystore/key_store_service.h
+++ b/keystore/key_store_service.h
@@ -132,9 +132,9 @@
const ::android::sp<::android::IBinder>& token, int32_t* _aidl_return) override;
::android::binder::Status addAuthToken(const ::std::vector<uint8_t>& authToken,
int32_t* _aidl_return) override;
- ::android::binder::Status
- getAuthTokenForCredstore(int64_t challenge, int64_t secureUserId, int32_t authTokenMaxAge,
- ::std::vector<uint8_t>* _aidl_return) override;
+ ::android::binder::Status getTokensForCredstore(
+ int64_t challenge, int64_t secureUserId, int32_t authTokenMaxAge,
+ const ::android::sp<::android::security::keystore::ICredstoreTokenCallback>& cb) override;
::android::binder::Status onUserAdded(int32_t userId, int32_t parentId,
int32_t* _aidl_return) override;
::android::binder::Status onUserRemoved(int32_t userId, int32_t* _aidl_return) override;
diff --git a/keystore/tests/Android.bp b/keystore/tests/Android.bp
index eac6fe6..883e020 100644
--- a/keystore/tests/Android.bp
+++ b/keystore/tests/Android.bp
@@ -13,6 +13,7 @@
"auth_token_formatting_test.cpp",
"blob_test.cpp",
"confirmationui_rate_limiting_test.cpp",
+ "verification_token_seralization_test.cpp",
"gtest_main.cpp",
],
name: "keystore_unit_tests",
diff --git a/keystore/tests/verification_token_seralization_test.cpp b/keystore/tests/verification_token_seralization_test.cpp
new file mode 100644
index 0000000..276541a
--- /dev/null
+++ b/keystore/tests/verification_token_seralization_test.cpp
@@ -0,0 +1,69 @@
+/*
+ * Copyright (C) 2015 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.
+ */
+
+#include <gtest/gtest.h>
+
+#include <keymasterV4_0/keymaster_utils.h>
+
+namespace keystore {
+namespace test {
+
+using android::hardware::keymaster::V4_0::SecurityLevel;
+using android::hardware::keymaster::V4_0::VerificationToken;
+using android::hardware::keymaster::V4_0::support::deserializeVerificationToken;
+using android::hardware::keymaster::V4_0::support::serializeVerificationToken;
+using std::optional;
+using std::vector;
+
+TEST(VerificationTokenSeralizationTest, SerializationTest) {
+ VerificationToken token;
+ token.challenge = 12345;
+ token.timestamp = 67890;
+ token.securityLevel = SecurityLevel::TRUSTED_ENVIRONMENT;
+ token.mac.resize(32);
+ for (size_t n = 0; n < 32; n++) {
+ token.mac[n] = n;
+ }
+ optional<vector<uint8_t>> serialized = serializeVerificationToken(token);
+ ASSERT_TRUE(serialized.has_value());
+ optional<VerificationToken> deserialized = deserializeVerificationToken(serialized.value());
+ ASSERT_TRUE(deserialized.has_value());
+ ASSERT_EQ(token.challenge, deserialized.value().challenge);
+ ASSERT_EQ(token.timestamp, deserialized.value().timestamp);
+ ASSERT_EQ(token.securityLevel, deserialized.value().securityLevel);
+ ASSERT_EQ(0u, deserialized.value().parametersVerified.size());
+ ASSERT_EQ(token.mac, deserialized.value().mac);
+}
+
+TEST(VerificationTokenSeralizationTest, SerializationTestNoMac) {
+ VerificationToken token;
+ token.challenge = 12345;
+ token.timestamp = 67890;
+ token.securityLevel = SecurityLevel::TRUSTED_ENVIRONMENT;
+ token.mac.resize(0);
+ optional<vector<uint8_t>> serialized = serializeVerificationToken(token);
+ ASSERT_TRUE(serialized.has_value());
+ optional<VerificationToken> deserialized = deserializeVerificationToken(serialized.value());
+ ASSERT_TRUE(deserialized.has_value());
+ ASSERT_EQ(token.challenge, deserialized.value().challenge);
+ ASSERT_EQ(token.timestamp, deserialized.value().timestamp);
+ ASSERT_EQ(token.securityLevel, deserialized.value().securityLevel);
+ ASSERT_EQ(0u, deserialized.value().parametersVerified.size());
+ ASSERT_EQ(token.mac, deserialized.value().mac);
+}
+
+} // namespace test
+} // namespace keystore