OpenPgpApi.java

  1/*
  2 * Copyright (C) 2014 Dominik Schürmann <dominik@dominikschuermann.de>
  3 *
  4 * Licensed under the Apache License, Version 2.0 (the "License");
  5 * you may not use this file except in compliance with the License.
  6 * You may obtain a copy of the License at
  7 *
  8 *      http://www.apache.org/licenses/LICENSE-2.0
  9 *
 10 * Unless required by applicable law or agreed to in writing, software
 11 * distributed under the License is distributed on an "AS IS" BASIS,
 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 13 * See the License for the specific language governing permissions and
 14 * limitations under the License.
 15 */
 16
 17package org.openintents.openpgp.util;
 18
 19import android.annotation.TargetApi;
 20import android.content.Context;
 21import android.content.Intent;
 22import android.os.AsyncTask;
 23import android.os.Build;
 24import android.os.ParcelFileDescriptor;
 25import android.util.Log;
 26
 27import org.openintents.openpgp.IOpenPgpService;
 28import org.openintents.openpgp.OpenPgpError;
 29
 30import java.io.InputStream;
 31import java.io.OutputStream;
 32
 33public class OpenPgpApi {
 34
 35    public static final String TAG = "OpenPgp API";
 36
 37    public static final String SERVICE_INTENT = "org.openintents.openpgp.IOpenPgpService";
 38
 39    /**
 40     * Version history
 41     * ---------------
 42     * <p/>
 43     * 3:
 44     * - first public stable version
 45     * <p/>
 46     * 4:
 47     * - No changes to existing methods -> backward compatible
 48     * - Introduction of ACTION_DECRYPT_METADATA, RESULT_METADATA, EXTRA_ORIGINAL_FILENAME, and OpenPgpMetadata parcel
 49     * - Introduction of internal NFC extras: EXTRA_NFC_SIGNED_HASH, EXTRA_NFC_SIG_CREATION_TIMESTAMP
 50     * 5:
 51     * - OpenPgpSignatureResult: new SIGNATURE_KEY_REVOKED and SIGNATURE_KEY_EXPIRED
 52     */
 53    public static final int API_VERSION = 5;
 54
 55    /**
 56     * General extras
 57     * --------------
 58     *
 59     * required extras:
 60     * int           EXTRA_API_VERSION           (always required)
 61     *
 62     * returned extras:
 63     * int           RESULT_CODE                 (RESULT_CODE_ERROR, RESULT_CODE_SUCCESS or RESULT_CODE_USER_INTERACTION_REQUIRED)
 64     * OpenPgpError  RESULT_ERROR                (if RESULT_CODE == RESULT_CODE_ERROR)
 65     * PendingIntent RESULT_INTENT               (if RESULT_CODE == RESULT_CODE_USER_INTERACTION_REQUIRED)
 66     */
 67
 68    /**
 69     * Sign only
 70     * <p/>
 71     * optional extras:
 72     * boolean       EXTRA_REQUEST_ASCII_ARMOR   (request ascii armor for output)
 73     * String        EXTRA_PASSPHRASE            (key passphrase)
 74     */
 75    public static final String ACTION_SIGN = "org.openintents.openpgp.action.SIGN";
 76
 77    /**
 78     * Encrypt
 79     * <p/>
 80     * required extras:
 81     * String[]      EXTRA_USER_IDS              (=emails of recipients, if more than one key has a user_id, a PendingIntent is returned via RESULT_INTENT)
 82     * or
 83     * long[]        EXTRA_KEY_IDS
 84     * <p/>
 85     * optional extras:
 86     * boolean       EXTRA_REQUEST_ASCII_ARMOR   (request ascii armor for output)
 87     * String        EXTRA_PASSPHRASE            (key passphrase)
 88     * String        EXTRA_ORIGINAL_FILENAME     (original filename to be encrypted as metadata)
 89     */
 90    public static final String ACTION_ENCRYPT = "org.openintents.openpgp.action.ENCRYPT";
 91
 92    /**
 93     * Sign and encrypt
 94     * <p/>
 95     * required extras:
 96     * String[]      EXTRA_USER_IDS              (=emails of recipients, if more than one key has a user_id, a PendingIntent is returned via RESULT_INTENT)
 97     * or
 98     * long[]        EXTRA_KEY_IDS
 99     * <p/>
100     * optional extras:
101     * boolean       EXTRA_REQUEST_ASCII_ARMOR   (request ascii armor for output)
102     * String        EXTRA_PASSPHRASE            (key passphrase)
103     * String        EXTRA_ORIGINAL_FILENAME     (original filename to be encrypted as metadata)
104     */
105    public static final String ACTION_SIGN_AND_ENCRYPT = "org.openintents.openpgp.action.SIGN_AND_ENCRYPT";
106
107    /**
108     * Decrypts and verifies given input stream. This methods handles encrypted-only, signed-and-encrypted,
109     * and also signed-only input.
110     * <p/>
111     * If OpenPgpSignatureResult.getStatus() == OpenPgpSignatureResult.SIGNATURE_KEY_MISSING
112     * in addition a PendingIntent is returned via RESULT_INTENT to download missing keys.
113     * <p/>
114     * optional extras:
115     * boolean       EXTRA_REQUEST_ASCII_ARMOR   (request ascii armor for output)
116     * <p/>
117     * returned extras:
118     * OpenPgpSignatureResult   RESULT_SIGNATURE
119     * OpenPgpDecryptMetadata   RESULT_METADATA
120     */
121    public static final String ACTION_DECRYPT_VERIFY = "org.openintents.openpgp.action.DECRYPT_VERIFY";
122
123    /**
124     * Decrypts the header of an encrypted file to retrieve metadata such as original filename.
125     * <p/>
126     * This does not decrypt the actual content of the file.
127     * <p/>
128     * returned extras:
129     * OpenPgpDecryptMetadata   RESULT_METADATA
130     */
131    public static final String ACTION_DECRYPT_METADATA = "org.openintents.openpgp.action.DECRYPT_METADATA";
132
133    /**
134     * Get key ids based on given user ids (=emails)
135     * <p/>
136     * required extras:
137     * String[]      EXTRA_USER_IDS
138     * <p/>
139     * returned extras:
140     * long[]        RESULT_KEY_IDS
141     */
142    public static final String ACTION_GET_KEY_IDS = "org.openintents.openpgp.action.GET_KEY_IDS";
143
144    /**
145     * This action returns RESULT_CODE_SUCCESS if the OpenPGP Provider already has the key
146     * corresponding to the given key id in its database.
147     * <p/>
148     * It returns RESULT_CODE_USER_INTERACTION_REQUIRED if the Provider does not have the key.
149     * The PendingIntent from RESULT_INTENT can be used to retrieve those from a keyserver.
150     * <p/>
151     * required extras:
152     * long        EXTRA_KEY_ID
153     */
154    public static final String ACTION_GET_KEY = "org.openintents.openpgp.action.GET_KEY";
155
156    /* Intent extras */
157    public static final String EXTRA_API_VERSION = "api_version";
158
159    public static final String EXTRA_ACCOUNT_NAME = "account_name";
160
161    // SIGN, ENCRYPT, SIGN_AND_ENCRYPT, DECRYPT_VERIFY
162    // request ASCII Armor for output
163    // OpenPGP Radix-64, 33 percent overhead compared to binary, see http://tools.ietf.org/html/rfc4880#page-53)
164    public static final String EXTRA_REQUEST_ASCII_ARMOR = "ascii_armor";
165
166    // ENCRYPT, SIGN_AND_ENCRYPT
167    public static final String EXTRA_USER_IDS = "user_ids";
168    public static final String EXTRA_KEY_IDS = "key_ids";
169    // optional extras:
170    public static final String EXTRA_PASSPHRASE = "passphrase";
171    public static final String EXTRA_ORIGINAL_FILENAME = "original_filename";
172
173    // internal NFC states
174    public static final String EXTRA_NFC_SIGNED_HASH = "nfc_signed_hash";
175    public static final String EXTRA_NFC_SIG_CREATION_TIMESTAMP = "nfc_sig_creation_timestamp";
176
177    // GET_KEY
178    public static final String EXTRA_KEY_ID = "key_id";
179    public static final String RESULT_KEY_IDS = "key_ids";
180
181    /* Service Intent returns */
182    public static final String RESULT_CODE = "result_code";
183
184    // get actual error object from RESULT_ERROR
185    public static final int RESULT_CODE_ERROR = 0;
186    // success!
187    public static final int RESULT_CODE_SUCCESS = 1;
188    // get PendingIntent from RESULT_INTENT, start PendingIntent with startIntentSenderForResult,
189    // and execute service method again in onActivityResult
190    public static final int RESULT_CODE_USER_INTERACTION_REQUIRED = 2;
191
192    public static final String RESULT_ERROR = "error";
193    public static final String RESULT_INTENT = "intent";
194
195    // DECRYPT_VERIFY
196    public static final String RESULT_SIGNATURE = "signature";
197    public static final String RESULT_METADATA = "metadata";
198
199    IOpenPgpService mService;
200    Context mContext;
201
202    public OpenPgpApi(Context context, IOpenPgpService service) {
203        this.mContext = context;
204        this.mService = service;
205    }
206
207    public interface IOpenPgpCallback {
208        void onReturn(final Intent result);
209    }
210
211    private class OpenPgpAsyncTask extends AsyncTask<Void, Integer, Intent> {
212        Intent data;
213        InputStream is;
214        OutputStream os;
215        IOpenPgpCallback callback;
216
217        private OpenPgpAsyncTask(Intent data, InputStream is, OutputStream os, IOpenPgpCallback callback) {
218            this.data = data;
219            this.is = is;
220            this.os = os;
221            this.callback = callback;
222        }
223
224        @Override
225        protected Intent doInBackground(Void... unused) {
226            return executeApi(data, is, os);
227        }
228
229        protected void onPostExecute(Intent result) {
230            callback.onReturn(result);
231        }
232
233    }
234
235    @TargetApi(Build.VERSION_CODES.HONEYCOMB)
236    public void executeApiAsync(Intent data, InputStream is, OutputStream os, IOpenPgpCallback callback) {
237        OpenPgpAsyncTask task = new OpenPgpAsyncTask(data, is, os, callback);
238
239        // don't serialize async tasks!
240        // http://commonsware.com/blog/2012/04/20/asynctask-threading-regression-confirmed.html
241        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
242            task.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR, (Void[]) null);
243        } else {
244            task.execute((Void[]) null);
245        }
246    }
247
248    public Intent executeApi(Intent data, InputStream is, OutputStream os) {
249        try {
250            data.putExtra(EXTRA_API_VERSION, OpenPgpApi.API_VERSION);
251
252            Intent result;
253
254            // pipe the input and output
255            ParcelFileDescriptor input = null;
256            if (is != null) {
257                input = ParcelFileDescriptorUtil.pipeFrom(is,
258                        new ParcelFileDescriptorUtil.IThreadListener() {
259
260                            @Override
261                            public void onThreadFinished(Thread thread) {
262                                //Log.d(OpenPgpApi.TAG, "Copy to service finished");
263                            }
264                        }
265                );
266            }
267            ParcelFileDescriptor output = null;
268            if (os != null) {
269                output = ParcelFileDescriptorUtil.pipeTo(os,
270                        new ParcelFileDescriptorUtil.IThreadListener() {
271
272                            @Override
273                            public void onThreadFinished(Thread thread) {
274                                //Log.d(OpenPgpApi.TAG, "Service finished writing!");
275                            }
276                        }
277                );
278            }
279
280            // blocks until result is ready
281            result = mService.execute(data, input, output);
282            // close() is required to halt the TransferThread
283            if (output != null) {
284                output.close();
285            }
286            // TODO: close input?
287
288            // set class loader to current context to allow unparcelling
289            // of OpenPgpError and OpenPgpSignatureResult
290            // http://stackoverflow.com/a/3806769
291            result.setExtrasClassLoader(mContext.getClassLoader());
292
293            return result;
294        } catch (Exception e) {
295            Log.e(OpenPgpApi.TAG, "Exception in executeApi call", e);
296            Intent result = new Intent();
297            result.putExtra(RESULT_CODE, RESULT_CODE_ERROR);
298            result.putExtra(RESULT_ERROR,
299                    new OpenPgpError(OpenPgpError.CLIENT_SIDE_ERROR, e.getMessage()));
300            return result;
301        }
302    }
303
304}