Exclude ephemeral networks from wifi backup

We compare the set of networks defined in the supplicant with the
set of networks described as "configured" by the Wifi Manager.  The
latter excludes ephemeral networks, so any network definition we
find in the supplicant data that we do not also find in the
configured network set, we ignore for backup purposes.

Bug 18917753

Change-Id: I8e0f258d0cdb72d7bf9482fafe64dc921419fcb2

1 files changed, 105 insertions, 29 deletions

diff --git a/packages/SettingsProvider/src/com/android/providers/settings/SettingsBackupAgent.java b/packages/SettingsProvider/src/com/android/providers/settings/SettingsBackupAgent.java
index 78af785..6b7ac8c 100644
--- a/packages/SettingsProvider/src/com/android/providers/settings/SettingsBackupAgent.java
+++ b/packages/SettingsProvider/src/com/android/providers/settings/SettingsBackupAgent.java
@@ -25,6 +25,8 @@ import android.content.ContentValues;
 import android.content.Context;
 import android.database.Cursor;
 import android.net.Uri;
+import android.net.wifi.WifiConfiguration;
+import android.net.wifi.WifiConfiguration.KeyMgmt;
 import android.net.wifi.WifiManager;
 import android.os.FileUtils;
 import android.os.Handler;
@@ -33,9 +35,12 @@ import android.os.Process;
 import android.provider.Settings;
 import android.util.Log;
 
+import libcore.io.IoUtils;
+
 import java.io.BufferedOutputStream;
 import java.io.BufferedReader;
 import java.io.BufferedWriter;
+import java.io.ByteArrayOutputStream;
 import java.io.CharArrayReader;
 import java.io.DataInputStream;
 import java.io.DataOutputStream;
@@ -48,11 +53,15 @@ import java.io.FileWriter;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
+import java.io.OutputStreamWriter;
 import java.io.Writer;
 import java.util.ArrayList;
+import java.util.BitSet;
 import java.util.HashMap;
 import java.util.HashSet;
+import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 import java.util.zip.CRC32;
 
 /**
@@ -138,6 +147,7 @@ public class SettingsBackupAgent extends BackupAgentHelper {
         String ssid = "";  // equals() and hashCode() need these to be non-null
         String key_mgmt = "";
         boolean certUsed = false;
+        boolean hasWepKey = false;
         final ArrayList<String> rawLines = new ArrayList<String>();
 
         public static Network readFromStream(BufferedReader in) {
@@ -164,9 +174,9 @@ public class SettingsBackupAgent extends BackupAgentHelper {
             rawLines.add(line);
 
             // remember the ssid and key_mgmt lines for duplicate culling
-            if (line.startsWith("ssid")) {
+            if (line.startsWith("ssid=")) {
                 ssid = line;
-            } else if (line.startsWith("key_mgmt")) {
+            } else if (line.startsWith("key_mgmt=")) {
                 key_mgmt = line;
             } else if (line.startsWith("client_cert=")) {
                 certUsed = true;
@@ -174,6 +184,8 @@ public class SettingsBackupAgent extends BackupAgentHelper {
                 certUsed = true;
             } else if (line.startsWith("ca_path=")) {
                 certUsed = true;
+            } else if (line.startsWith("wep_")) {
+                hasWepKey = true;
             }
         }
 
@@ -193,6 +205,56 @@ public class SettingsBackupAgent extends BackupAgentHelper {
             Log.v(TAG, "}");
         }
 
+        // Calculate the equivalent of WifiConfiguration's configKey()
+        public String configKey() {
+            if (ssid == null) {
+                // No SSID => malformed network definition
+                return null;
+            }
+
+            final String bareSsid = ssid.substring(ssid.indexOf('=') + 1);
+
+            final BitSet types = new BitSet();
+            if (key_mgmt == null) {
+                // no key_mgmt specified; this is defined as equivalent to "WPA-PSK WPA-EAP"
+                types.set(KeyMgmt.WPA_PSK);
+                types.set(KeyMgmt.WPA_EAP);
+            } else {
+                // Need to parse the key_mgmt line
+                final String bareKeyMgmt = key_mgmt.substring(key_mgmt.indexOf('=') + 1);
+                String[] typeStrings = bareKeyMgmt.split("\\s+");
+
+                // Parse out all the key management regimes permitted for this network.  The literal
+                // strings here are the standard values permitted in wpa_supplicant.conf.
+                for (int i = 0; i < typeStrings.length; i++) {
+                    final String ktype = typeStrings[i];
+                    if (ktype.equals("WPA-PSK")) {
+                        Log.v(TAG, "  + setting WPA_PSK bit");
+                        types.set(KeyMgmt.WPA_PSK);
+                    } else if (ktype.equals("WPA-EAP")) {
+                        Log.v(TAG, "  + setting WPA_EAP bit");
+                        types.set(KeyMgmt.WPA_EAP);
+                    } else if (ktype.equals("IEEE8021X")) {
+                        Log.v(TAG, "  + setting IEEE8021X bit");
+                        types.set(KeyMgmt.IEEE8021X);
+                    }
+                }
+            }
+
+            // Now build the canonical config key paralleling the WifiConfiguration semantics
+            final String key;
+            if (types.get(KeyMgmt.WPA_PSK)) {
+                key = bareSsid + KeyMgmt.strings[KeyMgmt.WPA_PSK];
+            } else if (types.get(KeyMgmt.WPA_EAP) || types.get(KeyMgmt.IEEE8021X)) {
+                key = bareSsid + KeyMgmt.strings[KeyMgmt.WPA_EAP];
+            } else if (hasWepKey) {
+                key = bareSsid + "WEP";  // hardcoded this way in WifiConfiguration
+            } else {
+                key = bareSsid + KeyMgmt.strings[KeyMgmt.NONE];
+            }
+            return key;
+        }
+
         // Same approach as Pair.equals() and Pair.hashCode()
         @Override
         public boolean equals(Object o) {
@@ -216,6 +278,17 @@ public class SettingsBackupAgent extends BackupAgentHelper {
         }
     }
 
+    boolean networkInWhitelist(Network net, List<WifiConfiguration> whitelist) {
+        final String netConfigKey = net.configKey();
+        final int N = whitelist.size();
+        for (int i = 0; i < N; i++) {
+            if (Objects.equals(netConfigKey, whitelist.get(i).configKey(true))) {
+                return true;
+            }
+        }
+        return false;
+    }
+
     // Ingest multiple wifi config file fragments, looking for network={} blocks
     // and eliminating duplicates
     class WifiNetworkSettings {
@@ -223,7 +296,7 @@ public class SettingsBackupAgent extends BackupAgentHelper {
         final HashSet<Network> mKnownNetworks = new HashSet<Network>();
         final ArrayList<Network> mNetworks = new ArrayList<Network>(8);
 
-        public void readNetworks(BufferedReader in) {
+        public void readNetworks(BufferedReader in, List<WifiConfiguration> whitelist) {
             try {
                 String line;
                 while (in.ready()) {
@@ -232,6 +305,15 @@ public class SettingsBackupAgent extends BackupAgentHelper {
                         // Parse out 'network=' decls so we can ignore duplicates
                         if (line.startsWith("network")) {
                             Network net = Network.readFromStream(in);
+                            if (whitelist != null) {
+                                if (!networkInWhitelist(net, whitelist)) {
+                                    if (DEBUG_BACKUP) {
+                                        Log.v(TAG, "Network not in whitelist, skipping: "
+                                                + net.ssid + " / " + net.key_mgmt);
+                                    }
+                                    continue;
+                                }
+                            }
                             if (! mKnownNetworks.contains(net)) {
                                 if (DEBUG_BACKUP) {
                                     Log.v(TAG, "Adding " + net.ssid + " / " + net.key_mgmt);
@@ -844,24 +926,23 @@ public class SettingsBackupAgent extends BackupAgentHelper {
         BufferedReader br = null;
         try {
             File file = new File(filename);
-            if (file.exists()) {
-                br = new BufferedReader(new FileReader(file));
-                StringBuffer relevantLines = new StringBuffer();
-                boolean started = false;
-                String line;
-                while ((line = br.readLine()) != null) {
-                    if (!started && line.startsWith("network")) {
-                        started = true;
-                    }
-                    if (started) {
-                        relevantLines.append(line).append("\n");
-                    }
-                }
-                if (relevantLines.length() > 0) {
-                    return relevantLines.toString().getBytes();
-                } else {
-                    return EMPTY_DATA;
-                }
+            if (!file.exists()) {
+                return EMPTY_DATA;
+            }
+
+            WifiManager wifi = (WifiManager) getSystemService(WIFI_SERVICE);
+            List<WifiConfiguration> configs = wifi.getConfiguredNetworks();
+
+            WifiNetworkSettings fromFile = new WifiNetworkSettings();
+            br = new BufferedReader(new FileReader(file));
+            fromFile.readNetworks(br, configs);
+
+            // Write the parsed networks into a packed byte array
+            if (fromFile.mKnownNetworks.size() > 0) {
+                ByteArrayOutputStream bos = new ByteArrayOutputStream();
+                OutputStreamWriter out = new OutputStreamWriter(bos);
+                fromFile.write(out);
+                return bos.toByteArray();
             } else {
                 return EMPTY_DATA;
             }
@@ -869,12 +950,7 @@ public class SettingsBackupAgent extends BackupAgentHelper {
             Log.w(TAG, "Couldn't backup " + filename);
             return EMPTY_DATA;
         } finally {
-            if (br != null) {
-                try {
-                    br.close();
-                } catch (IOException e) {
-                }
-            }
+            IoUtils.closeQuietly(br);
         }
     }
 
@@ -886,7 +962,7 @@ public class SettingsBackupAgent extends BackupAgentHelper {
             if (supplicantFile.exists()) {
                 // Retain the existing APs; we'll append the restored ones to them
                 BufferedReader in = new BufferedReader(new FileReader(FILE_WIFI_SUPPLICANT));
-                supplicantImage.readNetworks(in);
+                supplicantImage.readNetworks(in, null);
                 in.close();
 
                 supplicantFile.delete();
@@ -897,7 +973,7 @@ public class SettingsBackupAgent extends BackupAgentHelper {
                 char[] restoredAsBytes = new char[size];
                 for (int i = 0; i < size; i++) restoredAsBytes[i] = (char) bytes[i];
                 BufferedReader in = new BufferedReader(new CharArrayReader(restoredAsBytes));
-                supplicantImage.readNetworks(in);
+                supplicantImage.readNetworks(in, null);
 
                 if (DEBUG_BACKUP) {
                     Log.v(TAG, "Final AP list:");