session-android/src/org/thoughtcrime/securesms/transport/SmsTransport.java

/**
 * Copyright (C) 2013 Open Whisper Systems
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package org.thoughtcrime.securesms.transport;

import android.app.PendingIntent;
import android.content.Context;
import android.telephony.SmsManager;
import android.util.Log;

import org.thoughtcrime.securesms.crypto.IdentityKeyUtil;
import org.thoughtcrime.securesms.database.model.SmsMessageRecord;
import org.thoughtcrime.securesms.recipients.Recipient;
import org.thoughtcrime.securesms.service.SendReceiveService;
import org.thoughtcrime.securesms.service.SmsDeliveryListener;
import org.thoughtcrime.securesms.sms.MultipartSmsMessageHandler;
import org.thoughtcrime.securesms.sms.OutgoingPrekeyBundleMessage;
import org.thoughtcrime.securesms.sms.OutgoingTextMessage;
import org.thoughtcrime.securesms.sms.SmsTransportDetails;
import org.thoughtcrime.securesms.util.TextSecurePreferences;
import org.whispersystems.textsecure.crypto.IdentityKeyPair;
import org.whispersystems.textsecure.crypto.KeyUtil;
import org.whispersystems.textsecure.crypto.MasterSecret;
import org.whispersystems.textsecure.crypto.MessageCipher;
import org.whispersystems.textsecure.crypto.ecc.Curve;
import org.whispersystems.textsecure.crypto.ecc.ECPublicKey;
import org.whispersystems.textsecure.crypto.protocol.CiphertextMessage;
import org.whispersystems.textsecure.crypto.protocol.PreKeyBundleMessage;

import java.util.ArrayList;

public class SmsTransport extends BaseTransport {

  private final Context context;
  private final MasterSecret masterSecret;

  public SmsTransport(Context context, MasterSecret masterSecret) {
    this.context      = context.getApplicationContext();
    this.masterSecret = masterSecret;
  }

  public void deliver(SmsMessageRecord message) throws UndeliverableMessageException {
    if (message.isSecure() || message.isKeyExchange()) {
      deliverSecureMessage(message);
    } else {
      deliverPlaintextMessage(message);
    }
  }

  private void deliverSecureMessage(SmsMessageRecord message) throws UndeliverableMessageException {
    MultipartSmsMessageHandler multipartMessageHandler = new MultipartSmsMessageHandler();
    OutgoingTextMessage transportMessage               = OutgoingTextMessage.from(message);

    if (message.isSecure()) {
      transportMessage = getAsymmetricEncrypt(masterSecret, transportMessage);
    }

    ArrayList<String> messages                = multipartMessageHandler.divideMessage(transportMessage);
    ArrayList<PendingIntent> sentIntents      = constructSentIntents(message.getId(), message.getType(), messages);
    ArrayList<PendingIntent> deliveredIntents = constructDeliveredIntents(message.getId(), message.getType(), messages);

    Log.w("SmsTransport", "Secure divide into message parts: " + messages.size());

    for (int i=0;i<messages.size();i++) {
      // XXX moxie@thoughtcrime.org 1/7/11 -- There's apparently a bug where for some unknown recipients
      // and messages, this will throw an NPE.  I have no idea why, so I'm just catching it and marking
      // the message as a failure.  That way at least it doesn't repeatedly crash every time you start
      // the app.
      // d3sre 12/10/13 -- extended the log file to further analyse the problem
      try {
        SmsManager.getDefault().sendTextMessage(message.getIndividualRecipient().getNumber(), null, messages.get(i),
                                                sentIntents.get(i),
                                                deliveredIntents == null ? null : deliveredIntents.get(i));
      } catch (NullPointerException npe) {
        Log.w("SmsTransport", npe);
        Log.w("SmsTransport", "Recipient: " + message.getIndividualRecipient().getNumber());
        Log.w("SmsTransport", "Message Total Parts/Current: " + messages.size() + "/" + i);
        Log.w("SmsTransport", "Message Part Length: " + messages.get(i).getBytes().length);
        throw new UndeliverableMessageException(npe);
      } catch (IllegalArgumentException iae) {
        Log.w("SmsTransport", iae);
        throw new UndeliverableMessageException(iae);
      }
    }

  }

  private void deliverPlaintextMessage(SmsMessageRecord message)
      throws UndeliverableMessageException
  {
    ArrayList<String> messages                = SmsManager.getDefault().divideMessage(message.getBody().getBody());
    ArrayList<PendingIntent> sentIntents      = constructSentIntents(message.getId(), message.getType(), messages);
    ArrayList<PendingIntent> deliveredIntents = constructDeliveredIntents(message.getId(), message.getType(), messages);
    String recipient                          = message.getIndividualRecipient().getNumber();

    // XXX moxie@thoughtcrime.org 1/7/11 -- There's apparently a bug where for some unknown recipients
    // and messages, this will throw an NPE.  I have no idea why, so I'm just catching it and marking
    // the message as a failure.  That way at least it doesn't repeatedly crash every time you start
    // the app.
    // d3sre 12/10/13 -- extended the log file to further analyse the problem
    try {
      SmsManager.getDefault().sendMultipartTextMessage(recipient, null, messages, sentIntents, deliveredIntents);
    } catch (NullPointerException npe) {
      Log.w("SmsTransport", npe);
      Log.w("SmsTransport", "Recipient: " + recipient);
      Log.w("SmsTransport", "Message Parts: " + messages.size());

      try {
        for (int i=0;i<messages.size();i++) {
          SmsManager.getDefault().sendTextMessage(recipient, null, messages.get(i),
                                                  sentIntents.get(i),
                                                  deliveredIntents == null ? null : deliveredIntents.get(i));
        }
      } catch (NullPointerException npe2) {
        Log.w("SmsTransport", npe);
        throw new UndeliverableMessageException(npe2);
      }
    }
  }

  private ArrayList<PendingIntent> constructSentIntents(long messageId, long type, ArrayList<String> messages) {
    ArrayList<PendingIntent> sentIntents = new ArrayList<PendingIntent>(messages.size());

    for (String ignored : messages) {
      sentIntents.add(PendingIntent.getBroadcast(context, 0,
                                                 constructSentIntent(context, messageId, type),
                                                 0));
    }

    return sentIntents;
  }

  private ArrayList<PendingIntent> constructDeliveredIntents(long messageId, long type, ArrayList<String> messages) {
    if (!TextSecurePreferences.isSmsDeliveryReportsEnabled(context)) {
      return null;
    }

    ArrayList<PendingIntent> deliveredIntents = new ArrayList<PendingIntent>(messages.size());

    for (String ignored : messages) {
      deliveredIntents.add(PendingIntent.getBroadcast(context, 0,
                                                      constructDeliveredIntent(context, messageId, type),
                                                      0));
    }

    return deliveredIntents;
  }

  private OutgoingTextMessage getAsymmetricEncrypt(MasterSecret masterSecret,
                                                   OutgoingTextMessage message)
  {
    Recipient           recipient        = message.getRecipients().getPrimaryRecipient();
    String              body             = message.getMessageBody();
    IdentityKeyPair     identityKey      = IdentityKeyUtil.getIdentityKeyPair(context, masterSecret,
                                                                              Curve.DJB_TYPE);

    SmsTransportDetails transportDetails = new SmsTransportDetails();

    if (KeyUtil.isNonPrekeySessionFor(context, masterSecret, recipient)) {
      Log.w("SmsTransport", "Delivering standard ciphertext...");

      MessageCipher       messageCipher     = new MessageCipher(context, masterSecret, identityKey);
      byte[]              paddedPlaintext   = transportDetails.getPaddedMessageBody(body.getBytes());
      CiphertextMessage   ciphertextMessage = messageCipher.encrypt(recipient, paddedPlaintext);
      String              ciphertxt         = new String(transportDetails.getEncodedMessage(ciphertextMessage.serialize()));

      return message.withBody(ciphertxt);
    } else {
      Log.w("SmsTransport", "Delivering prekeybundle ciphertext...");
      MessageCipher       messageCipher       = new MessageCipher(context, masterSecret, identityKey);
      CiphertextMessage   ciphertextMessage   = messageCipher.encrypt(recipient, body.getBytes());
      PreKeyBundleMessage preKeyBundleMessage = new PreKeyBundleMessage(ciphertextMessage, identityKey.getPublicKey());
      byte[]              cipherText          = preKeyBundleMessage.serialize();

      return new OutgoingPrekeyBundleMessage(message, new String(transportDetails.getEncodedMessage(cipherText)));
    }
  }
}