MemorizingTrustManager.java

  1/* MemorizingTrustManager - a TrustManager which asks the user about invalid
  2 *  certificates and memorizes their decision.
  3 *
  4 * Copyright (c) 2010 Georg Lukas <georg@op-co.de>
  5 *
  6 * MemorizingTrustManager.java contains the actual trust manager and interface
  7 * code to create a MemorizingActivity and obtain the results.
  8 *
  9 * Permission is hereby granted, free of charge, to any person obtaining a copy
 10 * of this software and associated documentation files (the "Software"), to deal
 11 * in the Software without restriction, including without limitation the rights
 12 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 13 * copies of the Software, and to permit persons to whom the Software is
 14 * furnished to do so, subject to the following conditions:
 15 *
 16 * The above copyright notice and this permission notice shall be included in
 17 * all copies or substantial portions of the Software.
 18 *
 19 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 20 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 21 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 22 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 23 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 24 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 25 * THE SOFTWARE.
 26 */
 27package eu.siacs.conversations.services;
 28
 29import android.app.Application;
 30import android.app.NotificationManager;
 31import android.app.Service;
 32import android.content.Context;
 33import android.content.Intent;
 34import android.content.SharedPreferences;
 35import android.net.Uri;
 36import android.os.Handler;
 37import android.preference.PreferenceManager;
 38import android.util.Base64;
 39import android.util.Log;
 40import android.util.SparseArray;
 41
 42import androidx.appcompat.app.AppCompatActivity;
 43
 44import com.google.common.base.Charsets;
 45import com.google.common.io.CharStreams;
 46
 47import org.json.JSONArray;
 48import org.json.JSONException;
 49import org.json.JSONObject;
 50
 51import java.io.BufferedReader;
 52import java.io.File;
 53import java.io.FileInputStream;
 54import java.io.FileNotFoundException;
 55import java.io.FileOutputStream;
 56import java.io.IOException;
 57import java.io.InputStream;
 58import java.io.InputStreamReader;
 59import java.security.KeyStore;
 60import java.security.KeyStoreException;
 61import java.security.MessageDigest;
 62import java.security.NoSuchAlgorithmException;
 63import java.security.cert.Certificate;
 64import java.security.cert.CertificateEncodingException;
 65import java.security.cert.CertificateException;
 66import java.security.cert.CertificateExpiredException;
 67import java.security.cert.CertificateParsingException;
 68import java.security.cert.X509Certificate;
 69import java.text.SimpleDateFormat;
 70import java.util.ArrayList;
 71import java.util.Collection;
 72import java.util.Enumeration;
 73import java.util.List;
 74import java.util.Locale;
 75import java.util.logging.Level;
 76import java.util.logging.Logger;
 77import java.util.regex.Pattern;
 78
 79import javax.net.ssl.HostnameVerifier;
 80import javax.net.ssl.SSLSession;
 81import javax.net.ssl.TrustManager;
 82import javax.net.ssl.TrustManagerFactory;
 83import javax.net.ssl.X509TrustManager;
 84
 85import eu.siacs.conversations.R;
 86import eu.siacs.conversations.crypto.DomainHostnameVerifier;
 87import eu.siacs.conversations.entities.MTMDecision;
 88import eu.siacs.conversations.http.HttpConnectionManager;
 89import eu.siacs.conversations.persistance.FileBackend;
 90import eu.siacs.conversations.ui.MemorizingActivity;
 91
 92/**
 93 * A X509 trust manager implementation which asks the user about invalid
 94 * certificates and memorizes their decision.
 95 * <p>
 96 * The certificate validity is checked using the system default X509
 97 * TrustManager, creating a query Dialog if the check fails.
 98 * <p>
 99 * <b>WARNING:</b> This only works if a dedicated thread is used for
100 * opening sockets!
101 */
102public class MemorizingTrustManager {
103
104
105    final static String DECISION_INTENT = "de.duenndns.ssl.DECISION";
106    public final static String DECISION_INTENT_ID = DECISION_INTENT + ".decisionId";
107    public final static String DECISION_INTENT_CERT = DECISION_INTENT + ".cert";
108    public final static String DECISION_TITLE_ID = DECISION_INTENT + ".titleId";
109    final static String DECISION_INTENT_CHOICE = DECISION_INTENT + ".decisionChoice";
110    final static String NO_TRUST_ANCHOR = "Trust anchor for certification path not found.";
111    private static final Pattern PATTERN_IPV4 = Pattern.compile("\\A(25[0-5]|2[0-4]\\d|[0-1]?\\d?\\d)(\\.(25[0-5]|2[0-4]\\d|[0-1]?\\d?\\d)){3}\\z");
112    private static final Pattern PATTERN_IPV6_HEX4DECCOMPRESSED = Pattern.compile("\\A((?:[0-9A-Fa-f]{1,4}(?::[0-9A-Fa-f]{1,4})*)?) ::((?:[0-9A-Fa-f]{1,4}:)*)(25[0-5]|2[0-4]\\d|[0-1]?\\d?\\d)(\\.(25[0-5]|2[0-4]\\d|[0-1]?\\d?\\d)){3}\\z");
113    private static final Pattern PATTERN_IPV6_6HEX4DEC = Pattern.compile("\\A((?:[0-9A-Fa-f]{1,4}:){6,6})(25[0-5]|2[0-4]\\d|[0-1]?\\d?\\d)(\\.(25[0-5]|2[0-4]\\d|[0-1]?\\d?\\d)){3}\\z");
114    private static final Pattern PATTERN_IPV6_HEXCOMPRESSED = Pattern.compile("\\A((?:[0-9A-Fa-f]{1,4}(?::[0-9A-Fa-f]{1,4})*)?)::((?:[0-9A-Fa-f]{1,4}(?::[0-9A-Fa-f]{1,4})*)?)\\z");
115    private static final Pattern PATTERN_IPV6 = Pattern.compile("\\A(?:[0-9a-fA-F]{1,4}:){7}[0-9a-fA-F]{1,4}\\z");
116    private final static Logger LOGGER = Logger.getLogger(MemorizingTrustManager.class.getName());
117    private final static int NOTIFICATION_ID = 100509;
118    static String KEYSTORE_DIR = "KeyStore";
119    static String KEYSTORE_FILE = "KeyStore.bks";
120    private static int decisionId = 0;
121    private static final SparseArray<MTMDecision> openDecisions = new SparseArray<MTMDecision>();
122    Context master;
123    AppCompatActivity foregroundAct;
124    NotificationManager notificationManager;
125    Handler masterHandler;
126    private File keyStoreFile;
127    private KeyStore appKeyStore;
128    private final X509TrustManager defaultTrustManager;
129    private X509TrustManager appTrustManager;
130    private String poshCacheDir;
131
132    /**
133     * Creates an instance of the MemorizingTrustManager class that falls back to a custom TrustManager.
134     * <p>
135     * You need to supply the application context. This has to be one of:
136     * - Application
137     * - Activity
138     * - Service
139     * <p>
140     * The context is used for file management, to display the dialog /
141     * notification and for obtaining translated strings.
142     *
143     * @param m                   Context for the application.
144     * @param defaultTrustManager Delegate trust management to this TM. If null, the user must accept every certificate.
145     */
146    public MemorizingTrustManager(Context m, X509TrustManager defaultTrustManager) {
147        init(m);
148        this.appTrustManager = getTrustManager(appKeyStore);
149        this.defaultTrustManager = defaultTrustManager;
150    }
151
152    /**
153     * Creates an instance of the MemorizingTrustManager class using the system X509TrustManager.
154     * <p>
155     * You need to supply the application context. This has to be one of:
156     * - Application
157     * - Activity
158     * - Service
159     * <p>
160     * The context is used for file management, to display the dialog /
161     * notification and for obtaining translated strings.
162     *
163     * @param m Context for the application.
164     */
165    public MemorizingTrustManager(Context m) {
166        init(m);
167        this.appTrustManager = getTrustManager(appKeyStore);
168        this.defaultTrustManager = getTrustManager(null);
169    }
170
171    /**
172     * Changes the path for the KeyStore file.
173     * <p>
174     * The actual filename relative to the app's directory will be
175     * <code>app_<i>dirname</i>/<i>filename</i></code>.
176     *
177     * @param dirname  directory to store the KeyStore.
178     * @param filename file name for the KeyStore.
179     */
180    public static void setKeyStoreFile(String dirname, String filename) {
181        KEYSTORE_DIR = dirname;
182        KEYSTORE_FILE = filename;
183    }
184
185    private static boolean isIp(final String server) {
186        return server != null && (
187                PATTERN_IPV4.matcher(server).matches()
188                        || PATTERN_IPV6.matcher(server).matches()
189                        || PATTERN_IPV6_6HEX4DEC.matcher(server).matches()
190                        || PATTERN_IPV6_HEX4DECCOMPRESSED.matcher(server).matches()
191                        || PATTERN_IPV6_HEXCOMPRESSED.matcher(server).matches());
192    }
193
194    private static String getBase64Hash(X509Certificate certificate, String digest) throws CertificateEncodingException {
195        MessageDigest md;
196        try {
197            md = MessageDigest.getInstance(digest);
198        } catch (NoSuchAlgorithmException e) {
199            return null;
200        }
201        md.update(certificate.getEncoded());
202        return Base64.encodeToString(md.digest(), Base64.NO_WRAP);
203    }
204
205    private static String hexString(byte[] data) {
206        StringBuffer si = new StringBuffer();
207        for (int i = 0; i < data.length; i++) {
208            si.append(String.format("%02x", data[i]));
209            if (i < data.length - 1)
210                si.append(":");
211        }
212        return si.toString();
213    }
214
215    private static String certHash(final X509Certificate cert, String digest) {
216        try {
217            MessageDigest md = MessageDigest.getInstance(digest);
218            md.update(cert.getEncoded());
219            return hexString(md.digest());
220        } catch (java.security.cert.CertificateEncodingException e) {
221            return e.getMessage();
222        } catch (java.security.NoSuchAlgorithmException e) {
223            return e.getMessage();
224        }
225    }
226
227    public static void interactResult(int decisionId, int choice) {
228        MTMDecision d;
229        synchronized (openDecisions) {
230            d = openDecisions.get(decisionId);
231            openDecisions.remove(decisionId);
232        }
233        if (d == null) {
234            LOGGER.log(Level.SEVERE, "interactResult: aborting due to stale decision reference!");
235            return;
236        }
237        synchronized (d) {
238            d.state = choice;
239            d.notify();
240        }
241    }
242
243    void init(Context m) {
244        master = m;
245        masterHandler = new Handler(m.getMainLooper());
246        notificationManager = (NotificationManager) master.getSystemService(Context.NOTIFICATION_SERVICE);
247
248        Application app;
249        if (m instanceof Application) {
250            app = (Application) m;
251        } else if (m instanceof Service) {
252            app = ((Service) m).getApplication();
253        } else if (m instanceof AppCompatActivity) {
254            app = ((AppCompatActivity) m).getApplication();
255        } else
256            throw new ClassCastException("MemorizingTrustManager context must be either Activity or Service!");
257
258        File dir = app.getDir(KEYSTORE_DIR, Context.MODE_PRIVATE);
259        keyStoreFile = new File(dir + File.separator + KEYSTORE_FILE);
260
261        poshCacheDir = app.getCacheDir().getAbsolutePath() + "/posh_cache/";
262
263        appKeyStore = loadAppKeyStore();
264    }
265
266    /**
267     * Binds an Activity to the MTM for displaying the query dialog.
268     * <p>
269     * This is useful if your connection is run from a service that is
270     * triggered by user interaction -- in such cases the activity is
271     * visible and the user tends to ignore the service notification.
272     * <p>
273     * You should never have a hidden activity bound to MTM! Use this
274     * function in onResume() and @see unbindDisplayActivity in onPause().
275     *
276     * @param act Activity to be bound
277     */
278    public void bindDisplayActivity(AppCompatActivity act) {
279        foregroundAct = act;
280    }
281
282    /**
283     * Removes an Activity from the MTM display stack.
284     * <p>
285     * Always call this function when the Activity added with
286     * {@link #bindDisplayActivity(AppCompatActivity)} is hidden.
287     *
288     * @param act Activity to be unbound
289     */
290    public void unbindDisplayActivity(AppCompatActivity act) {
291        // do not remove if it was overridden by a different activity
292        if (foregroundAct == act)
293            foregroundAct = null;
294    }
295
296    /**
297     * Get a list of all certificate aliases stored in MTM.
298     *
299     * @return an {@link Enumeration} of all certificates
300     */
301    public Enumeration<String> getCertificates() {
302        try {
303            return appKeyStore.aliases();
304        } catch (KeyStoreException e) {
305            // this should never happen, however...
306            throw new RuntimeException(e);
307        }
308    }
309
310    /**
311     * Get a certificate for a given alias.
312     *
313     * @param alias the certificate's alias as returned by {@link #getCertificates()}.
314     * @return the certificate associated with the alias or <tt>null</tt> if none found.
315     */
316    public Certificate getCertificate(String alias) {
317        try {
318            return appKeyStore.getCertificate(alias);
319        } catch (KeyStoreException e) {
320            // this should never happen, however...
321            throw new RuntimeException(e);
322        }
323    }
324
325    /**
326     * Removes the given certificate from MTMs key store.
327     *
328     * <p>
329     * <b>WARNING</b>: this does not immediately invalidate the certificate. It is
330     * well possible that (a) data is transmitted over still existing connections or
331     * (b) new connections are created using TLS renegotiation, without a new cert
332     * check.
333     * </p>
334     *
335     * @param alias the certificate's alias as returned by {@link #getCertificates()}.
336     * @throws KeyStoreException if the certificate could not be deleted.
337     */
338    public void deleteCertificate(String alias) throws KeyStoreException {
339        appKeyStore.deleteEntry(alias);
340        keyStoreUpdated();
341    }
342
343    /**
344     * Creates a new hostname verifier supporting user interaction.
345     *
346     * <p>This method creates a new {@link HostnameVerifier} that is bound to
347     * the given instance of {@link MemorizingTrustManager}, and leverages an
348     * existing {@link HostnameVerifier}. The returned verifier performs the
349     * following steps, returning as soon as one of them succeeds:
350     * /p>
351     * <ol>
352     * <li>Success, if the wrapped defaultVerifier accepts the certificate.</li>
353     * <li>Success, if the server certificate is stored in the keystore under the given hostname.</li>
354     * <li>Ask the user and return accordingly.</li>
355     * <li>Failure on exception.</li>
356     * </ol>
357     *
358     * @param defaultVerifier the {@link HostnameVerifier} that should perform the actual check
359     * @return a new hostname verifier using the MTM's key store
360     * @throws IllegalArgumentException if the defaultVerifier parameter is null
361     */
362    public DomainHostnameVerifier wrapHostnameVerifier(final HostnameVerifier defaultVerifier, final boolean interactive) {
363        if (defaultVerifier == null)
364            throw new IllegalArgumentException("The default verifier may not be null");
365
366        return new MemorizingHostnameVerifier(defaultVerifier, interactive);
367    }
368
369    X509TrustManager getTrustManager(KeyStore ks) {
370        try {
371            TrustManagerFactory tmf = TrustManagerFactory.getInstance("X509");
372            tmf.init(ks);
373            for (TrustManager t : tmf.getTrustManagers()) {
374                if (t instanceof X509TrustManager) {
375                    return (X509TrustManager) t;
376                }
377            }
378        } catch (Exception e) {
379            // Here, we are covering up errors. It might be more useful
380            // however to throw them out of the constructor so the
381            // embedding app knows something went wrong.
382            LOGGER.log(Level.SEVERE, "getTrustManager(" + ks + ")", e);
383        }
384        return null;
385    }
386
387    KeyStore loadAppKeyStore() {
388        KeyStore ks;
389        try {
390            ks = KeyStore.getInstance(KeyStore.getDefaultType());
391        } catch (KeyStoreException e) {
392            LOGGER.log(Level.SEVERE, "getAppKeyStore()", e);
393            return null;
394        }
395        FileInputStream fileInputStream = null;
396        try {
397            ks.load(null, null);
398            fileInputStream = new FileInputStream(keyStoreFile);
399            ks.load(fileInputStream, "MTM".toCharArray());
400        } catch (java.io.FileNotFoundException e) {
401            LOGGER.log(Level.INFO, "getAppKeyStore(" + keyStoreFile + ") - file does not exist");
402        } catch (Exception e) {
403            LOGGER.log(Level.SEVERE, "getAppKeyStore(" + keyStoreFile + ")", e);
404        } finally {
405            FileBackend.close(fileInputStream);
406        }
407        return ks;
408    }
409
410    void storeCert(String alias, Certificate cert) {
411        try {
412            appKeyStore.setCertificateEntry(alias, cert);
413        } catch (KeyStoreException e) {
414            LOGGER.log(Level.SEVERE, "storeCert(" + cert + ")", e);
415            return;
416        }
417        keyStoreUpdated();
418    }
419
420    void storeCert(X509Certificate cert) {
421        storeCert(cert.getSubjectDN().toString(), cert);
422    }
423
424    void keyStoreUpdated() {
425        // reload appTrustManager
426        appTrustManager = getTrustManager(appKeyStore);
427
428        // store KeyStore to file
429        java.io.FileOutputStream fos = null;
430        try {
431            fos = new java.io.FileOutputStream(keyStoreFile);
432            appKeyStore.store(fos, "MTM".toCharArray());
433        } catch (Exception e) {
434            LOGGER.log(Level.SEVERE, "storeCert(" + keyStoreFile + ")", e);
435        } finally {
436            if (fos != null) {
437                try {
438                    fos.close();
439                } catch (IOException e) {
440                    LOGGER.log(Level.SEVERE, "storeCert(" + keyStoreFile + ")", e);
441                }
442            }
443        }
444    }
445
446    // if the certificate is stored in the app key store, it is considered "known"
447    private boolean isCertKnown(X509Certificate cert) {
448        try {
449            return appKeyStore.getCertificateAlias(cert) != null;
450        } catch (KeyStoreException e) {
451            return false;
452        }
453    }
454
455    private boolean isExpiredException(Throwable e) {
456        do {
457            if (e instanceof CertificateExpiredException)
458                return true;
459            e = e.getCause();
460        } while (e != null);
461        return false;
462    }
463
464    public void checkCertTrusted(X509Certificate[] chain, String authType, String domain, boolean isServer, boolean interactive)
465            throws CertificateException {
466        LOGGER.log(Level.FINE, "checkCertTrusted(" + chain + ", " + authType + ", " + isServer + ")");
467        try {
468            LOGGER.log(Level.FINE, "checkCertTrusted: trying appTrustManager");
469            if (isServer)
470                appTrustManager.checkServerTrusted(chain, authType);
471            else
472                appTrustManager.checkClientTrusted(chain, authType);
473        } catch (CertificateException ae) {
474            LOGGER.log(Level.FINER, "checkCertTrusted: appTrustManager failed", ae);
475            // if the cert is stored in our appTrustManager, we ignore expiredness
476            if (isExpiredException(ae)) {
477                LOGGER.log(Level.INFO, "checkCertTrusted: accepting expired certificate from keystore");
478                return;
479            }
480            if (isCertKnown(chain[0])) {
481                LOGGER.log(Level.INFO, "checkCertTrusted: accepting cert already stored in keystore");
482                return;
483            }
484            try {
485                if (defaultTrustManager == null)
486                    throw ae;
487                LOGGER.log(Level.FINE, "checkCertTrusted: trying defaultTrustManager");
488                if (isServer)
489                    defaultTrustManager.checkServerTrusted(chain, authType);
490                else
491                    defaultTrustManager.checkClientTrusted(chain, authType);
492            } catch (final CertificateException e) {
493                final SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(master);
494                final boolean trustSystemCAs = !preferences.getBoolean("dont_trust_system_cas", false);
495                if (domain != null && isServer && trustSystemCAs && !isIp(domain) && !domain.endsWith(".onion")) {
496                    final String hash = getBase64Hash(chain[0], "SHA-256");
497                    final List<String> fingerprints = getPoshFingerprints(domain);
498                    if (hash != null && fingerprints.size() > 0) {
499                        if (fingerprints.contains(hash)) {
500                            Log.d("mtm", "trusted cert fingerprint of " + domain + " via posh");
501                            return;
502                        } else {
503                            Log.d("mtm", "fingerprint " + hash + " not found in " + fingerprints);
504                        }
505                        if (getPoshCacheFile(domain).delete()) {
506                            Log.d("mtm", "deleted posh file for " + domain + " after not being able to verify");
507                        }
508                    }
509                }
510                if (interactive) {
511                    interactCert(chain, authType, e);
512                } else {
513                    throw e;
514                }
515            }
516        }
517    }
518
519    private List<String> getPoshFingerprints(String domain) {
520        final List<String> cached = getPoshFingerprintsFromCache(domain);
521        if (cached == null) {
522            return getPoshFingerprintsFromServer(domain);
523        } else {
524            return cached;
525        }
526    }
527
528    private List<String> getPoshFingerprintsFromServer(String domain) {
529        return getPoshFingerprintsFromServer(domain, "https://" + domain + "/.well-known/posh/xmpp-client.json", -1, true);
530    }
531
532    private List<String> getPoshFingerprintsFromServer(String domain, String url, int maxTtl, boolean followUrl) {
533        Log.d("mtm", "downloading json for " + domain + " from " + url);
534        final SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(master);
535        final boolean useTor = QuickConversationsService.isConversations() && preferences.getBoolean("use_tor", master.getResources().getBoolean(R.bool.use_tor));
536        try {
537            final List<String> results = new ArrayList<>();
538            final InputStream inputStream = HttpConnectionManager.open(url, useTor);
539            final String body = CharStreams.toString(new InputStreamReader(inputStream, Charsets.UTF_8));
540            final JSONObject jsonObject = new JSONObject(body);
541            int expires = jsonObject.getInt("expires");
542            if (expires <= 0) {
543                return new ArrayList<>();
544            }
545            if (maxTtl >= 0) {
546                expires = Math.min(maxTtl, expires);
547            }
548            String redirect;
549            try {
550                redirect = jsonObject.getString("url");
551            } catch (JSONException e) {
552                redirect = null;
553            }
554            if (followUrl && redirect != null && redirect.toLowerCase().startsWith("https")) {
555                return getPoshFingerprintsFromServer(domain, redirect, expires, false);
556            }
557            final JSONArray fingerprints = jsonObject.getJSONArray("fingerprints");
558            for (int i = 0; i < fingerprints.length(); i++) {
559                final JSONObject fingerprint = fingerprints.getJSONObject(i);
560                final String sha256 = fingerprint.getString("sha-256");
561                results.add(sha256);
562            }
563            writeFingerprintsToCache(domain, results, 1000L * expires + System.currentTimeMillis());
564            return results;
565        } catch (final Exception e) {
566            Log.d("mtm", "error fetching posh " + e.getMessage());
567            return new ArrayList<>();
568        }
569    }
570
571    private File getPoshCacheFile(String domain) {
572        return new File(poshCacheDir + domain + ".json");
573    }
574
575    private void writeFingerprintsToCache(String domain, List<String> results, long expires) {
576        final File file = getPoshCacheFile(domain);
577        file.getParentFile().mkdirs();
578        try {
579            file.createNewFile();
580            JSONObject jsonObject = new JSONObject();
581            jsonObject.put("expires", expires);
582            jsonObject.put("fingerprints", new JSONArray(results));
583            FileOutputStream outputStream = new FileOutputStream(file);
584            outputStream.write(jsonObject.toString().getBytes());
585            outputStream.flush();
586            outputStream.close();
587        } catch (Exception e) {
588            e.printStackTrace();
589        }
590    }
591
592    private List<String> getPoshFingerprintsFromCache(String domain) {
593        final File file = getPoshCacheFile(domain);
594        try {
595            final InputStream inputStream = new FileInputStream(file);
596            final String json = CharStreams.toString(new InputStreamReader(inputStream, Charsets.UTF_8));
597            final JSONObject jsonObject = new JSONObject(json);
598            long expires = jsonObject.getLong("expires");
599            long expiresIn = expires - System.currentTimeMillis();
600            if (expiresIn < 0) {
601                file.delete();
602                return null;
603            } else {
604                Log.d("mtm", "posh fingerprints expire in " + (expiresIn / 1000) + "s");
605            }
606            final List<String> result = new ArrayList<>();
607            final JSONArray jsonArray = jsonObject.getJSONArray("fingerprints");
608            for (int i = 0; i < jsonArray.length(); ++i) {
609                result.add(jsonArray.getString(i));
610            }
611            return result;
612        } catch (final IOException e) {
613            return null;
614        } catch (JSONException e) {
615            file.delete();
616            return null;
617        }
618    }
619
620    private X509Certificate[] getAcceptedIssuers() {
621        LOGGER.log(Level.FINE, "getAcceptedIssuers()");
622        return defaultTrustManager.getAcceptedIssuers();
623    }
624
625    private int createDecisionId(MTMDecision d) {
626        int myId;
627        synchronized (openDecisions) {
628            myId = decisionId;
629            openDecisions.put(myId, d);
630            decisionId += 1;
631        }
632        return myId;
633    }
634
635    private void certDetails(StringBuffer si, X509Certificate c) {
636        SimpleDateFormat validityDateFormater = new SimpleDateFormat("yyyy-MM-dd");
637        si.append("\n");
638        si.append(c.getSubjectDN().toString());
639        si.append("\n");
640        si.append(validityDateFormater.format(c.getNotBefore()));
641        si.append(" - ");
642        si.append(validityDateFormater.format(c.getNotAfter()));
643        si.append("\nSHA-256: ");
644        si.append(certHash(c, "SHA-256"));
645        si.append("\nSHA-1: ");
646        si.append(certHash(c, "SHA-1"));
647        si.append("\nSigned by: ");
648        si.append(c.getIssuerDN().toString());
649        si.append("\n");
650    }
651
652    private String certChainMessage(final X509Certificate[] chain, CertificateException cause) {
653        Throwable e = cause;
654        LOGGER.log(Level.FINE, "certChainMessage for " + e);
655        StringBuffer si = new StringBuffer();
656        if (e.getCause() != null) {
657            e = e.getCause();
658            // HACK: there is no sane way to check if the error is a "trust anchor
659            // not found", so we use string comparison.
660            if (NO_TRUST_ANCHOR.equals(e.getMessage())) {
661                si.append(master.getString(R.string.mtm_trust_anchor));
662            } else
663                si.append(e.getLocalizedMessage());
664            si.append("\n");
665        }
666        si.append("\n");
667        si.append(master.getString(R.string.mtm_connect_anyway));
668        si.append("\n\n");
669        si.append(master.getString(R.string.mtm_cert_details));
670        for (X509Certificate c : chain) {
671            certDetails(si, c);
672        }
673        return si.toString();
674    }
675
676    private String hostNameMessage(X509Certificate cert, String hostname) {
677        StringBuffer si = new StringBuffer();
678
679        si.append(master.getString(R.string.mtm_hostname_mismatch, hostname));
680        si.append("\n\n");
681        try {
682            Collection<List<?>> sans = cert.getSubjectAlternativeNames();
683            if (sans == null) {
684                si.append(cert.getSubjectDN());
685                si.append("\n");
686            } else for (List<?> altName : sans) {
687                Object name = altName.get(1);
688                if (name instanceof String) {
689                    si.append("[");
690                    si.append(altName.get(0));
691                    si.append("] ");
692                    si.append(name);
693                    si.append("\n");
694                }
695            }
696        } catch (CertificateParsingException e) {
697            e.printStackTrace();
698            si.append("<Parsing error: ");
699            si.append(e.getLocalizedMessage());
700            si.append(">\n");
701        }
702        si.append("\n");
703        si.append(master.getString(R.string.mtm_connect_anyway));
704        si.append("\n\n");
705        si.append(master.getString(R.string.mtm_cert_details));
706        certDetails(si, cert);
707        return si.toString();
708    }
709
710    /**
711     * Returns the top-most entry of the activity stack.
712     *
713     * @return the Context of the currently bound UI or the master context if none is bound
714     */
715    Context getUI() {
716        return (foregroundAct != null) ? foregroundAct : master;
717    }
718
719    int interact(final String message, final int titleId) {
720        /* prepare the MTMDecision blocker object */
721        MTMDecision choice = new MTMDecision();
722        final int myId = createDecisionId(choice);
723
724        masterHandler.post(new Runnable() {
725            public void run() {
726                Intent ni = new Intent(master, MemorizingActivity.class);
727                ni.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
728                ni.setData(Uri.parse(MemorizingTrustManager.class.getName() + "/" + myId));
729                ni.putExtra(DECISION_INTENT_ID, myId);
730                ni.putExtra(DECISION_INTENT_CERT, message);
731                ni.putExtra(DECISION_TITLE_ID, titleId);
732
733                // we try to directly start the activity and fall back to
734                // making a notification
735                try {
736                    getUI().startActivity(ni);
737                } catch (Exception e) {
738                    LOGGER.log(Level.FINE, "startActivity(MemorizingActivity)", e);
739                }
740            }
741        });
742
743        LOGGER.log(Level.FINE, "openDecisions: " + openDecisions + ", waiting on " + myId);
744        try {
745            synchronized (choice) {
746                choice.wait();
747            }
748        } catch (InterruptedException e) {
749            LOGGER.log(Level.FINER, "InterruptedException", e);
750        }
751        LOGGER.log(Level.FINE, "finished wait on " + myId + ": " + choice.state);
752        return choice.state;
753    }
754
755    void interactCert(final X509Certificate[] chain, String authType, CertificateException cause)
756            throws CertificateException {
757        switch (interact(certChainMessage(chain, cause), R.string.mtm_accept_cert)) {
758            case MTMDecision.DECISION_ALWAYS:
759                storeCert(chain[0]); // only store the server cert, not the whole chain
760            case MTMDecision.DECISION_ONCE:
761                break;
762            default:
763                throw (cause);
764        }
765    }
766
767    boolean interactHostname(X509Certificate cert, String hostname) {
768        switch (interact(hostNameMessage(cert, hostname), R.string.mtm_accept_servername)) {
769            case MTMDecision.DECISION_ALWAYS:
770                storeCert(hostname, cert);
771            case MTMDecision.DECISION_ONCE:
772                return true;
773            default:
774                return false;
775        }
776    }
777
778    public X509TrustManager getNonInteractive(String domain) {
779        return new NonInteractiveMemorizingTrustManager(domain);
780    }
781
782    public X509TrustManager getInteractive(String domain) {
783        return new InteractiveMemorizingTrustManager(domain);
784    }
785
786    public X509TrustManager getNonInteractive() {
787        return new NonInteractiveMemorizingTrustManager(null);
788    }
789
790    public X509TrustManager getInteractive() {
791        return new InteractiveMemorizingTrustManager(null);
792    }
793
794    class MemorizingHostnameVerifier implements DomainHostnameVerifier {
795        private final HostnameVerifier defaultVerifier;
796        private final boolean interactive;
797
798        public MemorizingHostnameVerifier(HostnameVerifier wrapped, boolean interactive) {
799            this.defaultVerifier = wrapped;
800            this.interactive = interactive;
801        }
802
803        @Override
804        public boolean verify(String domain, String hostname, SSLSession session) {
805            LOGGER.log(Level.FINE, "hostname verifier for " + domain + ", trying default verifier first");
806            // if the default verifier accepts the hostname, we are done
807            if (defaultVerifier instanceof DomainHostnameVerifier) {
808                if (((DomainHostnameVerifier) defaultVerifier).verify(domain, hostname, session)) {
809                    return true;
810                }
811            } else {
812                if (defaultVerifier.verify(domain, session)) {
813                    return true;
814                }
815            }
816
817
818            // otherwise, we check if the hostname is an alias for this cert in our keystore
819            try {
820                X509Certificate cert = (X509Certificate) session.getPeerCertificates()[0];
821                //Log.d(TAG, "cert: " + cert);
822                if (cert.equals(appKeyStore.getCertificate(domain.toLowerCase(Locale.US)))) {
823                    LOGGER.log(Level.FINE, "certificate for " + domain + " is in our keystore. accepting.");
824                    return true;
825                } else {
826                    LOGGER.log(Level.FINE, "server " + domain + " provided wrong certificate, asking user.");
827                    if (interactive) {
828                        return interactHostname(cert, domain);
829                    } else {
830                        return false;
831                    }
832                }
833            } catch (Exception e) {
834                e.printStackTrace();
835                return false;
836            }
837        }
838
839        @Override
840        public boolean verify(String domain, SSLSession sslSession) {
841            return verify(domain, null, sslSession);
842        }
843    }
844
845    private class NonInteractiveMemorizingTrustManager implements X509TrustManager {
846
847        private final String domain;
848
849        public NonInteractiveMemorizingTrustManager(String domain) {
850            this.domain = domain;
851        }
852
853        @Override
854        public void checkClientTrusted(X509Certificate[] chain, String authType) throws CertificateException {
855            MemorizingTrustManager.this.checkCertTrusted(chain, authType, domain, false, false);
856        }
857
858        @Override
859        public void checkServerTrusted(X509Certificate[] chain, String authType)
860                throws CertificateException {
861            MemorizingTrustManager.this.checkCertTrusted(chain, authType, domain, true, false);
862        }
863
864        @Override
865        public X509Certificate[] getAcceptedIssuers() {
866            return MemorizingTrustManager.this.getAcceptedIssuers();
867        }
868
869    }
870
871    private class InteractiveMemorizingTrustManager implements X509TrustManager {
872        private final String domain;
873
874        public InteractiveMemorizingTrustManager(String domain) {
875            this.domain = domain;
876        }
877
878        @Override
879        public void checkClientTrusted(X509Certificate[] chain, String authType) throws CertificateException {
880            MemorizingTrustManager.this.checkCertTrusted(chain, authType, domain, false, true);
881        }
882
883        @Override
884        public void checkServerTrusted(X509Certificate[] chain, String authType)
885                throws CertificateException {
886            MemorizingTrustManager.this.checkCertTrusted(chain, authType, domain, true, true);
887        }
888
889        @Override
890        public X509Certificate[] getAcceptedIssuers() {
891            return MemorizingTrustManager.this.getAcceptedIssuers();
892        }
893    }
894}