Report the true value of more RoR metrics

Design ErrorCode for errors of loadRebootEscrowData. Also report
the status of vbmeta digest, as we plan to associate k_k with
vbmeta in the future.

Bug: 179105110
Test: atest FrameworksServicesTests:RebootEscrowManagerTests
Change-Id: I07168a7bc4fd20d41df9b87136e1e5158129d7f6

2 files changed, 142 insertions, 14 deletions

diff --git a/services/core/java/com/android/server/locksettings/RebootEscrowManager.java b/services/core/java/com/android/server/locksettings/RebootEscrowManager.java
index 6e99cba6ea91..62156a89392e 100644
--- a/services/core/java/com/android/server/locksettings/RebootEscrowManager.java
+++ b/services/core/java/com/android/server/locksettings/RebootEscrowManager.java
@@ -15,14 +15,17 @@
  */
 
 package com.android.server.locksettings;
+
 import static android.os.UserHandle.USER_SYSTEM;
 
+import android.annotation.IntDef;
 import android.annotation.NonNull;
 import android.annotation.UserIdInt;
 import android.content.Context;
 import android.content.pm.UserInfo;
 import android.os.Handler;
 import android.os.SystemClock;
+import android.os.SystemProperties;
 import android.os.UserManager;
 import android.provider.DeviceConfig;
 import android.provider.Settings;
@@ -35,6 +38,8 @@ import com.android.internal.util.IndentingPrintWriter;
 import com.android.internal.widget.RebootEscrowListener;
 
 import java.io.IOException;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
 import java.text.SimpleDateFormat;
 import java.util.ArrayList;
 import java.util.Date;
@@ -67,6 +72,21 @@ class RebootEscrowManager {
     static final String REBOOT_ESCROW_KEY_ARMED_TIMESTAMP = "reboot_escrow_key_stored_timestamp";
 
     /**
+     * The verified boot 2.0 vbmeta digest of the current slot, the property value is always
+     * available after boot.
+     */
+    static final String VBMETA_DIGEST_PROP_NAME = "ro.boot.vbmeta.digest";
+    /**
+     * The system prop contains vbmeta digest of the inactive slot. The build property is set after
+     * an OTA update. RebootEscrowManager will store it in disk before the OTA reboot, so the value
+     * is available for vbmeta digest verification after the device reboots.
+     */
+    static final String OTHER_VBMETA_DIGEST_PROP_NAME = "ota.other.vbmeta_digest";
+    static final String REBOOT_ESCROW_KEY_VBMETA_DIGEST = "reboot_escrow_key_vbmeta_digest";
+    static final String REBOOT_ESCROW_KEY_OTHER_VBMETA_DIGEST =
+            "reboot_escrow_key_other_vbmeta_digest";
+
+    /**
      * Number of boots until we consider the escrow data to be stale for the purposes of metrics.
      * <p>
      * If the delta between the current boot number and the boot number stored when the mechanism
@@ -86,6 +106,27 @@ class RebootEscrowManager {
     private static final int DEFAULT_LOAD_ESCROW_DATA_RETRY_COUNT = 3;
     private static final int DEFAULT_LOAD_ESCROW_DATA_RETRY_INTERVAL_SECONDS = 30;
 
+    @IntDef(prefix = {"ERROR_"}, value = {
+            ERROR_NONE,
+            ERROR_UNKNOWN,
+            ERROR_NO_PROVIDER,
+            ERROR_LOAD_ESCROW_KEY,
+            ERROR_RETRY_COUNT_EXHAUSTED,
+            ERROR_UNLOCK_ALL_USERS,
+    })
+    @Retention(RetentionPolicy.SOURCE)
+    @interface RebootEscrowErrorCode {
+    }
+
+    static final int ERROR_NONE = 0;
+    static final int ERROR_UNKNOWN = 1;
+    static final int ERROR_NO_PROVIDER = 2;
+    static final int ERROR_LOAD_ESCROW_KEY = 3;
+    static final int ERROR_RETRY_COUNT_EXHAUSTED = 4;
+    static final int ERROR_UNLOCK_ALL_USERS = 5;
+
+    private @RebootEscrowErrorCode int mLoadEscrowDataErrorCode = ERROR_NONE;
+
     /**
      * Logs events for later debugging in bugreports.
      */
@@ -199,6 +240,10 @@ class RebootEscrowManager {
                     0);
         }
 
+        public long getCurrentTimeMillis() {
+            return System.currentTimeMillis();
+        }
+
         public int getLoadEscrowDataRetryLimit() {
             return DeviceConfig.getInt(DeviceConfig.NAMESPACE_OTA,
                     "load_escrow_data_retry_count", DEFAULT_LOAD_ESCROW_DATA_RETRY_COUNT);
@@ -221,6 +266,11 @@ class RebootEscrowManager {
         public RebootEscrowEventLog getEventLog() {
             return new RebootEscrowEventLog();
         }
+
+        public String getVbmetaDigest(boolean other) {
+            return other ? SystemProperties.get(OTHER_VBMETA_DIGEST_PROP_NAME)
+                    : SystemProperties.get(VBMETA_DIGEST_PROP_NAME);
+        }
     }
 
     RebootEscrowManager(Context context, Callbacks callbacks, LockSettingsStorage storage) {
@@ -261,6 +311,7 @@ class RebootEscrowManager {
         if (rebootEscrowUsers.isEmpty()) {
             Slog.i(TAG, "No reboot escrow data found for users,"
                     + " skipping loading escrow data");
+            clearMetricsStorage();
             return;
         }
 
@@ -284,6 +335,7 @@ class RebootEscrowManager {
         }
 
         Slog.w(TAG, "Failed to load reboot escrow data after " + attemptNumber + " attempts");
+        mLoadEscrowDataErrorCode = ERROR_RETRY_COUNT_EXHAUSTED;
         onGetRebootEscrowKeyFailed(users, attemptNumber);
     }
 
@@ -307,6 +359,9 @@ class RebootEscrowManager {
         }
 
         if (escrowKey == null) {
+            if (mLoadEscrowDataErrorCode == ERROR_NONE) {
+                mLoadEscrowDataErrorCode = ERROR_LOAD_ESCROW_KEY;
+            }
             onGetRebootEscrowKeyFailed(users, attemptNumber + 1);
             return;
         }
@@ -321,9 +376,48 @@ class RebootEscrowManager {
         // Clear the old key in keystore. A new key will be generated by new RoR requests.
         mKeyStoreManager.clearKeyStoreEncryptionKey();
 
+        if (!allUsersUnlocked && mLoadEscrowDataErrorCode == ERROR_NONE) {
+            mLoadEscrowDataErrorCode = ERROR_UNLOCK_ALL_USERS;
+        }
         onEscrowRestoreComplete(allUsersUnlocked, attemptNumber + 1);
     }
 
+    private void clearMetricsStorage() {
+        mStorage.removeKey(REBOOT_ESCROW_ARMED_KEY, USER_SYSTEM);
+        mStorage.removeKey(REBOOT_ESCROW_KEY_ARMED_TIMESTAMP, USER_SYSTEM);
+        mStorage.removeKey(REBOOT_ESCROW_KEY_VBMETA_DIGEST, USER_SYSTEM);
+        mStorage.removeKey(REBOOT_ESCROW_KEY_OTHER_VBMETA_DIGEST, USER_SYSTEM);
+    }
+
+    private int getVbmetaDigestStatusOnRestoreComplete() {
+        String currentVbmetaDigest = mInjector.getVbmetaDigest(false);
+        String vbmetaDigestStored = mStorage.getString(REBOOT_ESCROW_KEY_VBMETA_DIGEST,
+                "", USER_SYSTEM);
+        String vbmetaDigestOtherStored = mStorage.getString(REBOOT_ESCROW_KEY_OTHER_VBMETA_DIGEST,
+                "", USER_SYSTEM);
+
+        // The other vbmeta digest is never set, assume no slot switch is attempted.
+        if (vbmetaDigestOtherStored.isEmpty()) {
+            if (currentVbmetaDigest.equals(vbmetaDigestStored)) {
+                return FrameworkStatsLog
+                        .REBOOT_ESCROW_RECOVERY_REPORTED__VBMETA_DIGEST_STATUS__MATCH_EXPECTED_SLOT;
+            }
+            return FrameworkStatsLog
+                    .REBOOT_ESCROW_RECOVERY_REPORTED__VBMETA_DIGEST_STATUS__MISMATCH;
+        }
+
+        // The other vbmeta digest is set, we expect to boot into the new slot.
+        if (currentVbmetaDigest.equals(vbmetaDigestOtherStored)) {
+            return FrameworkStatsLog
+                    .REBOOT_ESCROW_RECOVERY_REPORTED__VBMETA_DIGEST_STATUS__MATCH_EXPECTED_SLOT;
+        } else if (currentVbmetaDigest.equals(vbmetaDigestStored)) {
+            return FrameworkStatsLog
+                    .REBOOT_ESCROW_RECOVERY_REPORTED__VBMETA_DIGEST_STATUS__MATCH_FALLBACK_SLOT;
+        }
+        return FrameworkStatsLog
+                .REBOOT_ESCROW_RECOVERY_REPORTED__VBMETA_DIGEST_STATUS__MISMATCH;
+    }
+
     private void reportMetricOnRestoreComplete(boolean success, int attemptCount) {
         int serviceType = mInjector.serverBasedResumeOnReboot()
                 ? FrameworkStatsLog.REBOOT_ESCROW_RECOVERY_REPORTED__TYPE__SERVER_BASED
@@ -331,26 +425,31 @@ class RebootEscrowManager {
 
         long armedTimestamp = mStorage.getLong(REBOOT_ESCROW_KEY_ARMED_TIMESTAMP, -1,
                 USER_SYSTEM);
-        mStorage.removeKey(REBOOT_ESCROW_KEY_ARMED_TIMESTAMP, USER_SYSTEM);
-        int escrowDurationInSeconds = armedTimestamp != -1
-                ? (int) (System.currentTimeMillis() - armedTimestamp) / 1000 : -1;
-
-        // TODO(b/179105110) design error code; and report the true value for other fields.
-        int vbmetaDigestStatus = FrameworkStatsLog
-                .REBOOT_ESCROW_RECOVERY_REPORTED__VBMETA_DIGEST_STATUS__MATCH_EXPECTED_SLOT;
+        int escrowDurationInSeconds = -1;
+        long currentTimeStamp = mInjector.getCurrentTimeMillis();
+        if (armedTimestamp != -1 && currentTimeStamp > armedTimestamp) {
+            escrowDurationInSeconds = (int) (currentTimeStamp - armedTimestamp) / 1000;
+        }
 
-        mInjector.reportMetric(success, 0 /* error code */, serviceType, attemptCount,
+        int vbmetaDigestStatus = getVbmetaDigestStatusOnRestoreComplete();
+        if (!success && mLoadEscrowDataErrorCode == ERROR_NONE) {
+            mLoadEscrowDataErrorCode = ERROR_UNKNOWN;
+        }
+        // TODO(179105110) report the duration since boot complete.
+        mInjector.reportMetric(success, mLoadEscrowDataErrorCode, serviceType, attemptCount,
                 escrowDurationInSeconds, vbmetaDigestStatus, -1);
+
+        mLoadEscrowDataErrorCode = ERROR_NONE;
     }
 
     private void onEscrowRestoreComplete(boolean success, int attemptCount) {
         int previousBootCount = mStorage.getInt(REBOOT_ESCROW_ARMED_KEY, -1, USER_SYSTEM);
-        mStorage.removeKey(REBOOT_ESCROW_ARMED_KEY, USER_SYSTEM);
 
         int bootCountDelta = mInjector.getBootCount() - previousBootCount;
         if (success || (previousBootCount != -1 && bootCountDelta <= BOOT_COUNT_TOLERANCE)) {
             reportMetricOnRestoreComplete(success, attemptCount);
         }
+        clearMetricsStorage();
     }
 
     private RebootEscrowKey getAndClearRebootEscrowKey(SecretKey kk) throws IOException {
@@ -358,6 +457,7 @@ class RebootEscrowManager {
         if (rebootEscrowProvider == null) {
             Slog.w(TAG,
                     "Had reboot escrow data for users, but RebootEscrowProvider is unavailable");
+            mLoadEscrowDataErrorCode = ERROR_NO_PROVIDER;
             return null;
         }
 
@@ -463,7 +563,7 @@ class RebootEscrowManager {
             return;
         }
 
-        mStorage.removeKey(REBOOT_ESCROW_ARMED_KEY, USER_SYSTEM);
+        clearMetricsStorage();
         rebootEscrowProvider.clearRebootEscrowKey();
 
         List<UserInfo> users = mUserManager.getUsers();
@@ -505,8 +605,13 @@ class RebootEscrowManager {
         boolean armedRebootEscrow = rebootEscrowProvider.storeRebootEscrowKey(escrowKey, kk);
         if (armedRebootEscrow) {
             mStorage.setInt(REBOOT_ESCROW_ARMED_KEY, mInjector.getBootCount(), USER_SYSTEM);
-            mStorage.setLong(REBOOT_ESCROW_KEY_ARMED_TIMESTAMP, System.currentTimeMillis(),
+            mStorage.setLong(REBOOT_ESCROW_KEY_ARMED_TIMESTAMP, mInjector.getCurrentTimeMillis(),
+                    USER_SYSTEM);
+            // Store the vbmeta digest of both slots.
+            mStorage.setString(REBOOT_ESCROW_KEY_VBMETA_DIGEST, mInjector.getVbmetaDigest(false),
                     USER_SYSTEM);
+            mStorage.setString(REBOOT_ESCROW_KEY_OTHER_VBMETA_DIGEST,
+                    mInjector.getVbmetaDigest(true), USER_SYSTEM);
             mEventLog.addEntry(RebootEscrowEvent.SET_ARMED_STATUS);
         }
 
diff --git a/services/tests/servicestests/src/com/android/server/locksettings/RebootEscrowManagerTests.java b/services/tests/servicestests/src/com/android/server/locksettings/RebootEscrowManagerTests.java
index 91342ce925f6..502b5e4c6633 100644
--- a/services/tests/servicestests/src/com/android/server/locksettings/RebootEscrowManagerTests.java
+++ b/services/tests/servicestests/src/com/android/server/locksettings/RebootEscrowManagerTests.java
@@ -21,6 +21,7 @@ import static android.content.pm.UserInfo.FLAG_PRIMARY;
 import static android.content.pm.UserInfo.FLAG_PROFILE;
 import static android.os.UserHandle.USER_SYSTEM;
 
+import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertTrue;
@@ -110,6 +111,8 @@ public class RebootEscrowManagerTests {
     public interface MockableRebootEscrowInjected {
         int getBootCount();
 
+        long getCurrentTimeMillis();
+
         void reportMetric(boolean success, int errorCode, int serviceType, int attemptCount,
                 int escrowDurationInSeconds, int vbmetaDigestStatus, int durationSinceBootComplete);
     }
@@ -205,6 +208,16 @@ public class RebootEscrowManagerTests {
         }
 
         @Override
+        public String getVbmetaDigest(boolean other) {
+            return other ? "" : "fake digest";
+        }
+
+        @Override
+        public long getCurrentTimeMillis() {
+            return mInjected.getCurrentTimeMillis();
+        }
+
+        @Override
         public void reportMetric(boolean success, int errorCode, int serviceType, int attemptCount,
                 int escrowDurationInSeconds, int vbmetaDigestStatus,
                 int durationSinceBootComplete) {
@@ -430,16 +443,21 @@ public class RebootEscrowManagerTests {
         // pretend reboot happens here
 
         when(mInjected.getBootCount()).thenReturn(1);
+        when(mInjected.getCurrentTimeMillis()).thenReturn(30000L);
+        mStorage.setLong(RebootEscrowManager.REBOOT_ESCROW_KEY_ARMED_TIMESTAMP, 10000L,
+                USER_SYSTEM);
         ArgumentCaptor<Boolean> metricsSuccessCaptor = ArgumentCaptor.forClass(Boolean.class);
         doNothing().when(mInjected).reportMetric(metricsSuccessCaptor.capture(),
                 eq(0) /* error code */, eq(1) /* HAL based */, eq(1) /* attempt count */,
-                anyInt(), anyInt(), anyInt());
+                eq(20), eq(0) /* vbmeta status */, anyInt());
         when(mRebootEscrow.retrieveKey()).thenAnswer(invocation -> keyByteCaptor.getValue());
 
         mService.loadRebootEscrowDataIfAvailable(null);
         verify(mRebootEscrow).retrieveKey();
         assertTrue(metricsSuccessCaptor.getValue());
         verify(mKeyStoreManager).clearKeyStoreEncryptionKey();
+        assertEquals(mStorage.getLong(RebootEscrowManager.REBOOT_ESCROW_KEY_ARMED_TIMESTAMP,
+                -1, USER_SYSTEM), -1);
     }
 
     @Test
@@ -468,7 +486,7 @@ public class RebootEscrowManagerTests {
         ArgumentCaptor<Boolean> metricsSuccessCaptor = ArgumentCaptor.forClass(Boolean.class);
         doNothing().when(mInjected).reportMetric(metricsSuccessCaptor.capture(),
                 eq(0) /* error code */, eq(2) /* Server based */, eq(1) /* attempt count */,
-                anyInt(), anyInt(), anyInt());
+                anyInt(), eq(0) /* vbmeta status */, anyInt());
 
         when(mServiceConnection.unwrap(any(), anyLong()))
                 .thenAnswer(invocation -> invocation.getArgument(0));
@@ -607,9 +625,14 @@ public class RebootEscrowManagerTests {
         when(mInjected.getBootCount()).thenReturn(10);
         when(mRebootEscrow.retrieveKey()).thenAnswer(invocation -> keyByteCaptor.getValue());
 
+        // Trigger a vbmeta digest mismatch
+        mStorage.setString(RebootEscrowManager.REBOOT_ESCROW_KEY_VBMETA_DIGEST,
+                "non sense value", USER_SYSTEM);
         mService.loadRebootEscrowDataIfAvailable(null);
         verify(mInjected).reportMetric(eq(true), eq(0) /* error code */, eq(1) /* HAL based */,
-                eq(1) /* attempt count */, anyInt(), anyInt(), anyInt());
+                eq(1) /* attempt count */, anyInt(), eq(2) /* vbmeta status */, anyInt());
+        assertEquals(mStorage.getString(RebootEscrowManager.REBOOT_ESCROW_KEY_VBMETA_DIGEST,
+                "", USER_SYSTEM), "");
     }
 
     @Test