sign local repo based on key generated using spongycastle

This makes it so the local repo is always signed by a locally generated and
stored key.  That key will become the unique ID that represents a given
local repo.  It should seamlessly upgrade any existing unsigned local repo
next time that the user makes any changes to their local repo.

fixes #3380 https://dev.guardianproject.info/issues/3380

res/values/strings.xml

@@ -175,6 +175,7 @@
 	<string name="deleting_repo">Deleting current repo&#8230;</string>
 	<string name="adding_apks_format">Adding %s to repo&#8230;</string>
 	<string name="writing_index_xml">Writing raw index file (index.xml)&#8230;</string>
+	<string name="writing_index_jar">Writing signed index file (index.jar)&#8230;</string>
 	<string name="linking_apks">Linking APKs into the repo&#8230;</string>
 	<string name="copying_icons">Copying app icons into the repo&#8230;</string>
 	<string name="updated_local_repo">Finished updating local repo</string>

src/org/fdroid/fdroid/localrepo/LocalRepoKeyStore.java

@@ -211,30 +211,6 @@ public class LocalRepoKeyStore {
         return null;
     }
 
-    // This is take from FDroid: org.fdroid.fdroid.DB.calcFingerprint()
-    // TODO once this code is part of FDroid, replace this with DB.calcFingerprint()
-    public String getFingerprint() {
-        String ret = null;
-        try {
-            Certificate cert = getCertificate();
-            if (cert != null) {
-                MessageDigest digest = MessageDigest.getInstance("SHA-256");
-                digest.update(cert.getEncoded());
-                byte[] fingerprint = digest.digest();
-                Formatter formatter = new Formatter(new StringBuilder());
-                for (int i = 0; i < fingerprint.length; i++) {
-                    formatter.format("%02X", fingerprint[i]);
-                }
-                ret = formatter.toString();
-                formatter.close();
-            }
-        } catch (Exception e) {
-            e.printStackTrace();
-        }
-
-        return ret;
-    }
-
     public Certificate getCertificate() {
         try {
             Key key = keyStore.getKey(INDEX_CERT_ALIAS, "".toCharArray());

src/org/fdroid/fdroid/localrepo/LocalRepoManager.java

@@ -16,9 +16,9 @@ import android.preference.PreferenceManager;
 import android.text.TextUtils;
 import android.util.Log;
 
+import org.fdroid.fdroid.Hasher;
 import org.fdroid.fdroid.Preferences;
 import org.fdroid.fdroid.Utils;
-import org.fdroid.fdroid.data.Apk;
 import org.fdroid.fdroid.data.App;
 import org.w3c.dom.Document;
 import org.w3c.dom.Element;
@@ -28,6 +28,8 @@ import java.security.cert.CertificateEncodingException;
 import java.text.SimpleDateFormat;
 import java.util.*;
 import java.util.Map.Entry;
+import java.util.jar.JarEntry;
+import java.util.jar.JarOutputStream;
 
 import javax.xml.parsers.DocumentBuilder;
 import javax.xml.parsers.DocumentBuilderFactory;
@@ -42,6 +44,7 @@ public class LocalRepoManager {
     // For ref, official F-droid repo presently uses a maxage of 14 days
     private static final String DEFAULT_REPO_MAX_AGE_DAYS = "14";
 
+    private final Context context;
     private final PackageManager pm;
     private final AssetManager assetManager;
     private final SharedPreferences prefs;
@@ -53,12 +56,15 @@ public class LocalRepoManager {
     private Map<String, App> apps = new HashMap<String, App>();
 
     public final File xmlIndex;
+    private File xmlIndexJar = null;
+    private File xmlIndexJarUnsigned = null;
     public final File webRoot;
     public final File fdroidDir;
     public final File repoDir;
     public final File iconsDir;
 
     public LocalRepoManager(Context c) {
+        context = c;
         pm = c.getPackageManager();
         assetManager = c.getAssets();
         prefs = PreferenceManager.getDefaultSharedPreferences(c);
@@ -70,6 +76,8 @@ public class LocalRepoManager {
         repoDir = new File(fdroidDir, "repo");
         iconsDir = new File(repoDir, "icons");
         xmlIndex = new File(repoDir, "index.xml");
+        xmlIndexJar = new File(repoDir, "index.jar");
+        xmlIndexJarUnsigned = new File(repoDir, "index.unsigned.jar");
 
         if (!fdroidDir.exists())
             if (!fdroidDir.mkdir())
@@ -278,6 +286,7 @@ public class LocalRepoManager {
         repo.setAttribute("icon", "blah.png");
         repo.setAttribute("maxage", String.valueOf(repoMaxAge));
         repo.setAttribute("name", repoName + " on " + ipAddressString);
+        repo.setAttribute("pubkey", Hasher.hex(LocalRepoKeyStore.get(context).getCertificate()));
         long timestamp = System.currentTimeMillis() / 1000L;
         repo.setAttribute("timestamp", String.valueOf(timestamp));
         repo.setAttribute("url", uriString);
@@ -417,4 +426,30 @@ public class LocalRepoManager {
 
         transformer.transform(domSource, result);
     }
+
+    public void writeIndexJar() throws IOException {
+        BufferedOutputStream bo = new BufferedOutputStream(
+                new FileOutputStream(xmlIndexJarUnsigned));
+        JarOutputStream jo = new JarOutputStream(bo);
+
+        BufferedInputStream bi = new BufferedInputStream(new FileInputStream(xmlIndex));
+
+        JarEntry je = new JarEntry("index.xml");
+        jo.putNextEntry(je);
+
+        byte[] buf = new byte[1024];
+        int bytesRead;
+
+        while ((bytesRead = bi.read(buf)) != -1) {
+            jo.write(buf, 0, bytesRead);
+        }
+
+        bi.close();
+        jo.close();
+        bo.close();
+
+        LocalRepoKeyStore.get(context).signZip(xmlIndexJarUnsigned, xmlIndexJar);
+
+        xmlIndexJarUnsigned.delete();
+    }
 }

src/org/fdroid/fdroid/localrepo/LocalRepoService.java

@@ -201,7 +201,7 @@ public class LocalRepoService extends Service {
         values.put("path", "/fdroid/repo");
         values.put("name", repoName);
         // TODO set type based on "use HTTPS" pref
-        // values.put("fingerprint", FDroidApp.repo.fingerprint);
+        values.put("fingerprint", FDroidApp.repo.fingerprint);
         values.put("type", "fdroidrepo");
         pairService = ServiceInfo.create("_http._tcp.local.",
                 repoName, FDroidApp.port, 0, 0, values);

src/org/fdroid/fdroid/net/WifiStateChangeService.java

@@ -2,7 +2,6 @@
 package org.fdroid.fdroid.net;
 
 import android.app.Service;
-import android.content.Context;
 import android.content.Intent;
 import android.content.SharedPreferences;
 import android.net.wifi.WifiInfo;
@@ -16,7 +15,9 @@ import android.util.Log;
 import org.fdroid.fdroid.FDroidApp;
 import org.fdroid.fdroid.Preferences;
 import org.fdroid.fdroid.Utils;
+import org.fdroid.fdroid.localrepo.LocalRepoKeyStore;
 
+import java.security.cert.Certificate;
 import java.util.Locale;
 
 public class WifiStateChangeService extends Service {
@@ -67,6 +68,8 @@ public class WifiStateChangeService extends Service {
                 FDroidApp.repo.name = Preferences.get().getLocalRepoName();
                 FDroidApp.repo.address = String.format(Locale.ENGLISH, "%s://%s:%d/fdroid/repo",
                         scheme, FDroidApp.ipAddressString, FDroidApp.port);
+                Certificate localCert = LocalRepoKeyStore.get(getApplication()).getCertificate();
+                FDroidApp.repo.fingerprint = Utils.calcFingerprint(localCert);
                 FDroidApp.localRepo.setUriString(FDroidApp.repo.address);
                 FDroidApp.localRepo.writeIndexPage(
                         Utils.getSharingUri(WifiStateChangeService.this, FDroidApp.repo).toString());

src/org/fdroid/fdroid/views/LocalRepoActivity.java

@@ -22,9 +22,17 @@ import android.view.*;
 import android.widget.*;
 
 import org.fdroid.fdroid.*;
+import org.fdroid.fdroid.localrepo.LocalRepoKeyStore;
 import org.fdroid.fdroid.localrepo.LocalRepoService;
 import org.fdroid.fdroid.net.WifiStateChangeService;
+import org.spongycastle.operator.OperatorCreationException;
 
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.security.KeyStoreException;
+import java.security.NoSuchAlgorithmException;
+import java.security.UnrecoverableKeyException;
+import java.security.cert.CertificateException;
 import java.util.Locale;
 import java.util.Timer;
 import java.util.TimerTask;
@@ -252,6 +260,28 @@ public class LocalRepoActivity extends Activity {
             fingerprintTextView.setVisibility(View.GONE);
         }
 
+        // Once the IP address is known we need to generate a self signed
+        // certificate to use for HTTPS that has a CN field set to the
+        // ipAddressString. We'll generate it even if useHttps is false
+        // to simplify having to detect when that preference changes.
+        try {
+            LocalRepoKeyStore.get(this).setupHTTPSCertificate();
+        } catch (UnrecoverableKeyException e) {
+            e.printStackTrace();
+        } catch (CertificateException e) {
+            e.printStackTrace();
+        } catch (OperatorCreationException e) {
+            e.printStackTrace();
+        } catch (KeyStoreException e) {
+            e.printStackTrace();
+        } catch (NoSuchAlgorithmException e) {
+            e.printStackTrace();
+        } catch (FileNotFoundException e) {
+            e.printStackTrace();
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+
         // the required NFC API was added in 4.0 aka Ice Cream Sandwich
         if (Build.VERSION.SDK_INT >= 14) {
             NfcAdapter nfcAdapter = NfcAdapter.getDefaultAdapter(this);
@@ -300,6 +330,8 @@ public class LocalRepoActivity extends Activity {
                 FDroidApp.localRepo.writeIndexPage(sharingUri.toString());
                 publishProgress(getString(R.string.writing_index_xml));
                 FDroidApp.localRepo.writeIndexXML();
+                publishProgress(getString(R.string.writing_index_jar));
+                FDroidApp.localRepo.writeIndexJar();
                 publishProgress(getString(R.string.linking_apks));
                 FDroidApp.localRepo.copyApksToRepo();
                 publishProgress(getString(R.string.copying_icons));

src/org/fdroid/fdroid/views/fragments/RepoListFragment.java

@@ -200,8 +200,7 @@ public class RepoListFragment extends ListFragment
                 MenuItemCompat.SHOW_AS_ACTION_ALWAYS |
                         MenuItemCompat.SHOW_AS_ACTION_WITH_TEXT);
 
-        if (Build.VERSION.SDK_INT >= 16)
+        if (Build.VERSION.SDK_INT >= 16) {
-        {
             menu.add(Menu.NONE, SCAN_FOR_REPOS, 1, R.string.menu_scan_repo).setIcon(
                     android.R.drawable.ic_menu_search);
         }
@@ -271,8 +270,7 @@ public class RepoListFragment extends ListFragment
                     path = "/fdroid/repo";
                 String serviceUrl = protocol + serviceInfo.getInetAddresses()[0]
                         + ":" + serviceInfo.getPort() + path;
-                // TODO get fingerprint from TXT record
+                showAddRepo(serviceUrl, serviceInfo.getPropertyString("fingerprint"));
-                showAddRepo(serviceUrl, "");
             }
         });