DevicePolicyManager: Add key generation functionality.

This is the crux of the Verified Access feature implementation:
Adding the ability to generate KeyChain keys directly by the
secure hardware, rather than installing software-generated keys
into KeyChain.

Add generateKeyPair to the DevicePolicyManager, which delegates key
generation (via the DevicePolicyManagerService) to the KeyChainService.

Design highlights:
* The key generation is delegated via the DevicePolicyManagerService to
  check that only authorized callers request key generation in KeyChain.
* KeyChainService performs the actual key generation so it owns the key
  in Keystore outright.
* DevicePolicyManagerService then grants the calling app access to the
  Keystore key, so it can actually be used.
* Loading the public/private key pair, as well as attestation
  certificate chain, is done in the client code (DevicePolicyManager)
  to save parceling / unparceling those objects across process
  boundaries twice (for no good reason).

NOTE: The key attestation functionality (that includes Device ID) is
missing/untested. Will be added in a follow-up CL as this one is quite
big already.

HIGHLIGHT FOR REVIEWERS:
* API: New API in DevicePolicyManager.

Bug: 63388672
Test: cts-tradefed run commandAndExit cts-dev -a armeabi-v7a -m CtsDevicePolicyManagerTestCases -t com.android.cts.devicepolicy.DeviceOwnerTest#testKeyManagement -l DEBUG; adb shell am instrument 'android.security.tests/android.support.test.runner.AndroidJUnitRunner' (After building the KeystoreTests target and installing the apk)
Change-Id: I73762c9123f32a94d454ba4f8b533883b55c44cc

1 files changed, 75 insertions, 0 deletions

diff --git a/keystore/java/android/security/AttestedKeyPair.java b/keystore/java/android/security/AttestedKeyPair.java
new file mode 100644
index 000000000000..c6bff5c11a5d
--- /dev/null
+++ b/keystore/java/android/security/AttestedKeyPair.java
@@ -0,0 +1,75 @@
+/*
+ * Copyright (C) 2017 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;
+
+import java.security.KeyPair;
+import java.security.cert.Certificate;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+/**
+ * The {@code AttestedKeyPair} class contains a {@code KeyPair} instance of
+ * keys generated by Keystore and owned by KeyChain, as well as an attestation
+ * record for the key.
+ *
+ * <p>Such keys can be obtained by calling
+ * {@link android.app.admin.DevicePolicyManager#generateKeyPair}.
+ */
+
+public final class AttestedKeyPair {
+    private final KeyPair mKeyPair;
+    private final Certificate[] mAttestationRecord;
+
+    /**
+     * @hide Only created by the platform, no need to expose as public API.
+     */
+    public AttestedKeyPair(KeyPair keyPair, Certificate[] attestationRecord) {
+        mKeyPair = keyPair;
+        mAttestationRecord = attestationRecord;
+    }
+
+    /**
+     * Returns the generated key pair associated with the attestation record
+     * in this instance.
+     */
+    public KeyPair getKeyPair() {
+        return mKeyPair;
+    }
+
+    /**
+     * Returns the attestation record for the key pair in this instance.
+     *
+     * The attestation record is a chain of certificates. The leaf certificate links to the public
+     * key of this key pair and other properties of the key or the device. If the key is in secure
+     * hardware, and if the secure hardware supports attestation, the leaf certificate will be
+     * signed by a chain of certificates rooted at a trustworthy CA key. Otherwise the chain will be
+     * rooted at an untrusted certificate.
+     *
+     * The attestation record could be for properties of the key, or include device identifiers.
+     *
+     * See {@link android.security.keystore.KeyGenParameterSpec.Builder#setAttestationChallenge}
+     * and  <a href="https://developer.android.com/training/articles/security-key-attestation.html">
+     * Key Attestation</a> for the format of the attestation record inside the certificate.
+     */
+    public List<Certificate> getAttestationRecord() {
+        if (mAttestationRecord == null) {
+            return new ArrayList();
+        }
+        return Arrays.asList(mAttestationRecord);
+    }
+}