WifiBackupRestore: Handle network UIDs

Don't save creatorUID element for backup/restore. All networks will be
restored with the System UID set as the creatorUID. The creator UID is
hard to preserve across backup/restore.

Also, since the creatorUID is not being backed, there are genuine cases
where the configKey mismatch might occur. So, move the |configKey|
mismatch check out of |XmlUtil| and let backup/restore & config store
handle it differently as needed.

PS: Need to also figure out if we should stop backing up all networks
not saved by settings agent (creatorUid != SYSTEM_UD). Will wait for
discussions in b/29201888 to decide on that.

BUG: 29201888
TEST: Unit-tests
Change-Id: I668281893de9260a803872c04646b5af28ee45e5

5 files changed, 83 insertions, 28 deletions

diff --git a/service/java/com/android/server/wifi/WifiBackupRestore.java b/service/java/com/android/server/wifi/WifiBackupRestore.java
index d17b777d0..02954d4a8 100644
--- a/service/java/com/android/server/wifi/WifiBackupRestore.java
+++ b/service/java/com/android/server/wifi/WifiBackupRestore.java
@@ -20,6 +20,7 @@ import android.net.IpConfiguration;
 import android.net.wifi.WifiConfiguration;
 import android.net.wifi.WifiEnterpriseConfig;
 import android.util.Log;
+import android.util.Pair;
 import android.util.SparseArray;
 import android.util.Xml;
 
@@ -259,6 +260,36 @@ public class WifiBackupRestore {
     }
 
     /**
+     * Helper method to parse the WifiConfiguration object and validate the configKey parsed.
+     */
+    private WifiConfiguration parseWifiConfigurationFromXmlAndValidateConfigKey(
+            XmlPullParser in, int outerTagDepth)
+            throws XmlPullParserException, IOException {
+        Pair<String, WifiConfiguration> parsedConfig =
+                WifiConfigurationXmlUtil.parseWifiConfigurationFromXml(in, outerTagDepth);
+        if (parsedConfig == null || parsedConfig.first == null || parsedConfig.second == null) {
+            return null;
+        }
+        String configKeyParsed = parsedConfig.first;
+        WifiConfiguration configuration = parsedConfig.second;
+        String configKeyCalculated = configuration.configKey();
+        if (!configKeyParsed.equals(configKeyCalculated)) {
+            String configKeyMismatchLog =
+                    "Configuration key does not match. Retrieved: " + configKeyParsed
+                            + ", Calculated: " + configKeyCalculated;
+            if (configuration.shared) {
+                Log.e(TAG, configKeyMismatchLog);
+                return null;
+            } else {
+                // ConfigKey mismatches are expected for private networks because the
+                // UID is not preserved across backup/restore.
+                Log.w(TAG, configKeyMismatchLog);
+            }
+        }
+       return configuration;
+    }
+
+    /**
      * Parses the configuration data elements from the provided XML stream to a Configuration.
      *
      * @param in            XmlPullParser instance pointing to the XML stream.
@@ -278,7 +309,7 @@ public class WifiBackupRestore {
                     in, XML_TAG_SECTION_HEADER_WIFI_CONFIGURATION, networkTagDepth)) {
                 int configTagDepth = networkTagDepth + 1;
                 configuration =
-                        WifiConfigurationXmlUtil.parseWifiConfigurationFromXml(in, configTagDepth);
+                        parseWifiConfigurationFromXmlAndValidateConfigKey(in, configTagDepth);
                 if (configuration == null) {
                     return null;
                 }
@@ -661,13 +692,12 @@ public class WifiBackupRestore {
                     String idString =
                             mParsedIdStrLine.substring(mParsedIdStrLine.indexOf('=') + 1);
                     Map<String, String> extras = WifiNative.parseNetworkExtra(idString);
-                    configuration.creatorUid =
-                            Integer.valueOf(extras.get(WifiConfigStore.ID_STRING_KEY_CREATOR_UID));
                     String configKey = extras.get(WifiConfigStore.ID_STRING_KEY_CONFIG_KEY);
                     if (!configKey.equals(configuration.configKey())) {
-                        Log.e(TAG, "Configuration key does not match. Retrieved: " + configKey
+                        // ConfigKey mismatches are expected for private networks because the
+                        // UID is not preserved across backup/restore.
+                        Log.w(TAG, "Configuration key does not match. Retrieved: " + configKey
                                 + ", Calculated: " + configuration.configKey());
-                        return null;
                     }
                 }
                 return configuration;
diff --git a/service/java/com/android/server/wifi/util/XmlUtil.java b/service/java/com/android/server/wifi/util/XmlUtil.java
index 4b8fec308..c5f7a9eed 100644
--- a/service/java/com/android/server/wifi/util/XmlUtil.java
+++ b/service/java/com/android/server/wifi/util/XmlUtil.java
@@ -26,6 +26,7 @@ import android.net.RouteInfo;
 import android.net.StaticIpConfiguration;
 import android.net.wifi.WifiConfiguration;
 import android.util.Log;
+import android.util.Pair;
 
 import com.android.internal.util.XmlUtils;
 
@@ -259,6 +260,7 @@ public class XmlUtil {
         public static final String XML_TAG_ALLOWED_AUTH_ALGOS = "AllowedAuthAlgos";
         public static final String XML_TAG_SHARED = "Shared";
         public static final String XML_TAG_CREATOR_UID = "CreatorUid";
+        public static final String XML_TAG_CREATOR_NAME = "CreatorName";
 
         /**
          * Write WepKeys to the XML stream.
@@ -314,7 +316,6 @@ public class XmlUtil {
                     out, XML_TAG_ALLOWED_AUTH_ALGOS,
                     configuration.allowedAuthAlgorithms.toByteArray());
             XmlUtil.writeNextValue(out, XML_TAG_SHARED, configuration.shared);
-            XmlUtil.writeNextValue(out, XML_TAG_CREATOR_UID, configuration.creatorUid);
         }
 
         /**
@@ -340,10 +341,13 @@ public class XmlUtil {
                 throws XmlPullParserException, IOException {
             writeCommonWifiConfigurationElementsToXml(out, configuration);
             // TODO: Will need to add more elements which needs to be persisted.
+            XmlUtil.writeNextValue(out, XML_TAG_CREATOR_UID, configuration.creatorUid);
+            XmlUtil.writeNextValue(out, XML_TAG_CREATOR_NAME, configuration.creatorName);
         }
 
         /**
          * Populate wepKeys array elements only if they were non-empty in the backup data.
+         *
          * @throws XmlPullParserException if parsing errors occur.
          */
         private static void populateWepKeysFromXmlValue(Object value, String[] wepKeys)
@@ -372,10 +376,11 @@ public class XmlUtil {
          *
          * @param in            XmlPullParser instance pointing to the XML stream.
          * @param outerTagDepth depth of the outer tag in the XML document.
-         * @return WifiConfiguration object if parsing is successful, null otherwise.
+         * @return Pair<Config key, WifiConfiguration object> if parsing is successful,
+         * null otherwise.
          */
-        public static WifiConfiguration parseWifiConfigurationFromXml(XmlPullParser in,
-                int outerTagDepth)
+        public static Pair<String, WifiConfiguration> parseWifiConfigurationFromXml(
+                XmlPullParser in, int outerTagDepth)
                 throws XmlPullParserException, IOException {
             WifiConfiguration configuration = new WifiConfiguration();
             String configKeyInData = null;
@@ -428,20 +433,15 @@ public class XmlUtil {
                     case XML_TAG_CREATOR_UID:
                         configuration.creatorUid = (int) value;
                         break;
+                    case XML_TAG_CREATOR_NAME:
+                        configuration.creatorName = (String) value;
+                        break;
                     default:
                         Log.e(TAG, "Unknown value name found: " + valueName[0]);
                         return null;
                 }
             }
-            // We should now have all the data to calculate the configKey. Compare it against the
-            // configKey stored in the XML data.
-            String configKeyCalculated = configuration.configKey();
-            if (configKeyInData == null || !configKeyInData.equals(configKeyCalculated)) {
-                Log.e(TAG, "Configuration key does not match. Retrieved: " + configKeyInData
-                        + ", Calculated: " + configKeyCalculated);
-                return null;
-            }
-            return configuration;
+            return Pair.create(configKeyInData, configuration);
         }
     }
 
diff --git a/tests/wifitests/src/com/android/server/wifi/WifiBackupRestoreTest.java b/tests/wifitests/src/com/android/server/wifi/WifiBackupRestoreTest.java
index 0ca9eab15..c813cfaf6 100644
--- a/tests/wifitests/src/com/android/server/wifi/WifiBackupRestoreTest.java
+++ b/tests/wifitests/src/com/android/server/wifi/WifiBackupRestoreTest.java
@@ -775,7 +775,7 @@ public class WifiBackupRestoreTest {
             for (WifiConfiguration actualConfiguration : actual) {
                 String actualConfigKey = actualConfiguration.configKey();
                 if (actualConfigKey.equals(expectedConfigKey)) {
-                    WifiConfigurationTestUtil.assertConfigurationEqual(
+                    WifiConfigurationTestUtil.assertConfigurationEqualForBackup(
                             expectedConfiguration, actualConfiguration);
                     didCompare = true;
                 }
diff --git a/tests/wifitests/src/com/android/server/wifi/WifiConfigurationTestUtil.java b/tests/wifitests/src/com/android/server/wifi/WifiConfigurationTestUtil.java
index 85fe81b58..a7e47ffae 100644
--- a/tests/wifitests/src/com/android/server/wifi/WifiConfigurationTestUtil.java
+++ b/tests/wifitests/src/com/android/server/wifi/WifiConfigurationTestUtil.java
@@ -96,9 +96,10 @@ public class WifiConfigurationTestUtil {
     }
 
     /**
-     * Asserts that the 2 WifiConfigurations are equal
+     * Asserts that the 2 WifiConfigurations are equal in the elements saved for both backup/restore
+     * and config store.
      */
-    public static void assertConfigurationEqual(
+    private static void assertCommonConfigurationElementsEqual(
             WifiConfiguration expected, WifiConfiguration actual) {
         assertEquals(expected.SSID, actual.SSID);
         assertEquals(expected.BSSID, actual.BSSID);
@@ -110,7 +111,26 @@ public class WifiConfigurationTestUtil {
         assertEquals(expected.allowedProtocols, actual.allowedProtocols);
         assertEquals(expected.allowedAuthAlgorithms, actual.allowedAuthAlgorithms);
         assertEquals(expected.shared, actual.shared);
-        assertEquals(expected.creatorUid, actual.creatorUid);
         assertEquals(expected.getIpConfiguration(), actual.getIpConfiguration());
     }
+
+    /**
+     * Asserts that the 2 WifiConfigurations are equal. This only compares the elements saved
+     * fpr backup/restore.
+     */
+    public static void assertConfigurationEqualForBackup(
+            WifiConfiguration expected, WifiConfiguration actual) {
+        assertCommonConfigurationElementsEqual(expected, actual);
+    }
+
+    /**
+     * Asserts that the 2 WifiConfigurations are equal. This compares all the elements saved for
+     * config store.
+     */
+    public static void assertConfigurationEqualForConfigStore(
+            WifiConfiguration expected, WifiConfiguration actual) {
+        assertCommonConfigurationElementsEqual(expected, actual);
+        assertEquals(expected.creatorUid, actual.creatorUid);
+        assertEquals(expected.creatorName, actual.creatorName);
+    }
 }
diff --git a/tests/wifitests/src/com/android/server/wifi/util/XmlUtilTest.java b/tests/wifitests/src/com/android/server/wifi/util/XmlUtilTest.java
index fd07ab2c1..d53c51384 100644
--- a/tests/wifitests/src/com/android/server/wifi/util/XmlUtilTest.java
+++ b/tests/wifitests/src/com/android/server/wifi/util/XmlUtilTest.java
@@ -23,6 +23,7 @@ import android.net.ProxyInfo;
 import android.net.StaticIpConfiguration;
 import android.net.wifi.WifiConfiguration;
 import android.test.suitebuilder.annotation.SmallTest;
+import android.util.Pair;
 import android.util.Xml;
 
 import com.android.internal.util.FastXmlSerializer;
@@ -286,7 +287,7 @@ public class XmlUtilTest {
         return outputStream.toByteArray();
     }
 
-    private WifiConfiguration deserializeWifiConfiguration(byte[] data)
+    private Pair<String, WifiConfiguration> deserializeWifiConfiguration(byte[] data)
             throws IOException, XmlPullParserException {
         // Deserialize the configuration object.
         final XmlPullParser in = Xml.newPullParser();
@@ -301,18 +302,22 @@ public class XmlUtilTest {
      */
     private void serializeDeserializeWifiConfiguration(WifiConfiguration configuration)
             throws IOException, XmlPullParserException {
-        WifiConfiguration retrievedConfiguration;
+        Pair<String, WifiConfiguration> retrieved;
         // Test serialization/deserialization for backup first.
-        retrievedConfiguration =
+        retrieved =
                 deserializeWifiConfiguration(
                         serializeWifiConfigurationForBackup(configuration));
-        WifiConfigurationTestUtil.assertConfigurationEqual(configuration, retrievedConfiguration);
+        assertEquals(retrieved.first, retrieved.second.configKey());
+        WifiConfigurationTestUtil.assertConfigurationEqualForBackup(
+                configuration, retrieved.second);
 
         // Test serialization/deserialization for config store.
-        retrievedConfiguration =
+        retrieved =
                 deserializeWifiConfiguration(
                         serializeWifiConfigurationForConfigStore(configuration));
-        WifiConfigurationTestUtil.assertConfigurationEqual(configuration, retrievedConfiguration);
+        assertEquals(retrieved.first, retrieved.second.configKey());
+        WifiConfigurationTestUtil.assertConfigurationEqualForConfigStore(
+                configuration, retrieved.second);
     }
 
     private void serializeDeserializeIpConfiguration(IpConfiguration configuration)