some playing with content stream decryption and providing the result as content stream

src/org/thialfihar/android/apg/Apg.java

@@ -37,7 +37,6 @@ import java.util.Date;
 import java.util.GregorianCalendar;
 import java.util.HashMap;
 import java.util.Iterator;
-import java.util.List;
 import java.util.Map;
 import java.util.Vector;
 import java.util.regex.Pattern;
@@ -118,7 +117,8 @@ public class Apg {
     public static final String EXTRA_STATUS = "status";
     public static final String EXTRA_ERROR = "error";
     public static final String EXTRA_DECRYPTED_MESSAGE = "decryptedMessage";
-    public static final String EXTRA_ENCRYPTED_MESSAGE = "decryptedMessage";
+    public static final String EXTRA_ENCRYPTED_MESSAGE = "encryptedMessage";
+    public static final String EXTRA_RESULT_URI = "resultUri";
     public static final String EXTRA_SIGNATURE = "signature";
     public static final String EXTRA_SIGNATURE_KEY_ID = "signatureKeyId";
     public static final String EXTRA_SIGNATURE_USER_ID = "signatureUserId";
@@ -1851,4 +1851,43 @@ public class Apg {
     public static String getFullVersion(Context context) {
         return "APG v" + getVersion(context);
     }
+
+    public static String generateRandomString(int length) {
+        SecureRandom random = new SecureRandom();
+        /*
+        try {
+            random = SecureRandom.getInstance("SHA1PRNG", new BouncyCastleProvider());
+        } catch (NoSuchAlgorithmException e) {
+            // TODO: need to handle this case somehow
+            return null;
+        }*/
+        byte bytes[] = new byte[length];
+        random.nextBytes(bytes);
+        String result = "";
+        for (int i = 0; i < length; ++i) {
+            int v = ((int)bytes[i] + 256) % 64;
+            if (v < 10) {
+                result += (char)((int)'0' + v);
+            } else if (v < 36) {
+                result += (char)((int)'A' + v - 10);
+            } else if (v < 62) {
+                result += (char)((int)'a' + v - 36);
+            } else if (v == 62) {
+                result += '_';
+            } else if (v == 63) {
+                result += '.';
+            }
+        }
+        return result;
+    }
+
+    static long getLengthOfStream(InputStream in) throws IOException {
+        long size = 0;
+        long n = 0;
+        byte dummy[] = new byte[0x10000];
+        while ((n = in.read(dummy)) > 0) {
+            size += n;
+        }
+        return size;
+    }
 }

src/org/thialfihar/android/apg/DecryptActivity.java

@@ -31,6 +31,7 @@ import java.util.regex.Matcher;
 
 import org.bouncycastle2.jce.provider.BouncyCastleProvider;
 import org.bouncycastle2.openpgp.PGPException;
+import org.thialfihar.android.apg.provider.DataProvider;
 
 import android.app.Dialog;
 import android.content.ActivityNotFoundException;
@@ -86,6 +87,8 @@ public class DecryptActivity extends BaseActivity {
     private String mInputFilename = null;
     private String mOutputFilename = null;
 
+    private Uri mContentUri = null;
+
     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
@@ -220,26 +223,29 @@ public class DecryptActivity extends BaseActivity {
                 mSource.showNext();
             }
         } else if (Apg.Intent.DECRYPT_AND_RETURN.equals(mIntent.getAction())) {
-            Bundle extras = mIntent.getExtras();
+            mContentUri = mIntent.getData();
-            if (extras == null) {
+            if (mContentUri == null) {
-                extras = new Bundle();
+                Bundle extras = mIntent.getExtras();
-            }
+                if (extras == null) {
-            String data = extras.getString(Apg.EXTRA_TEXT);
+                    extras = new Bundle();
-            if (data != null) {
+                }
-                Matcher matcher = Apg.PGP_MESSAGE.matcher(data);
+                String data = extras.getString(Apg.EXTRA_TEXT);
-                if (matcher.matches()) {
+                if (data != null) {
-                    data = matcher.group(1);
+                    Matcher matcher = Apg.PGP_MESSAGE.matcher(data);
-                    // replace non breakable spaces
-                    data = data.replaceAll("\\xa0", " ");
-                    mMessage.setText(data);
-                } else {
-                    matcher = Apg.PGP_SIGNED_MESSAGE.matcher(data);
                     if (matcher.matches()) {
                         data = matcher.group(1);
                         // replace non breakable spaces
                         data = data.replaceAll("\\xa0", " ");
                         mMessage.setText(data);
-                        mDecryptButton.setText(R.string.btn_verify);
+                    } else {
+                        matcher = Apg.PGP_SIGNED_MESSAGE.matcher(data);
+                        if (matcher.matches()) {
+                            data = matcher.group(1);
+                            // replace non breakable spaces
+                            data = data.replaceAll("\\xa0", " ");
+                            mMessage.setText(data);
+                            mDecryptButton.setText(R.string.btn_verify);
+                        }
                     }
                 }
             }
@@ -393,7 +399,9 @@ public class DecryptActivity extends BaseActivity {
         String error = null;
         try {
             InputStream in;
-            if (mDecryptTarget == Id.target.file) {
+            if (mContentUri != null) {
+                in = getContentResolver().openInputStream(mContentUri);
+            } else if (mDecryptTarget == Id.target.file) {
                 if (mInputFilename.startsWith("file")) {
                     in = new FileInputStream(mInputFilename);
                 } else {
@@ -412,7 +420,9 @@ public class DecryptActivity extends BaseActivity {
                 setSecretKeyId(Id.key.symmetric);
                 // look at the file/message again to check whether there's
                 // symmetric encryption data in there
-                if (mDecryptTarget == Id.target.file) {
+                if (mContentUri != null) {
+                    in = getContentResolver().openInputStream(mContentUri);
+                } else if (mDecryptTarget == Id.target.file) {
                     if (mInputFilename.startsWith("file")) {
                         in = new FileInputStream(mInputFilename);
                     } else {
@@ -494,22 +504,32 @@ public class DecryptActivity extends BaseActivity {
         try {
             PositionAwareInputStream in = null;
             OutputStream out = null;
+            String randomString = null;
             long size = 0;
 
-            if (mDecryptTarget == Id.target.message) {
+            if (mContentUri != null) {
+                in = new PositionAwareInputStream(getContentResolver().openInputStream(mContentUri));
+                size = Apg.getLengthOfStream(getContentResolver().openInputStream(mContentUri));
+                try {
+                    while (true) {
+                        randomString = Apg.generateRandomString(32);
+                        if (randomString == null) {
+                            throw new Apg.GeneralException("couldn't generate random file name");
+                        }
+                        this.openFileInput(randomString).close();
+                    }
+                } catch (FileNotFoundException e) {
+                    // found a name that isn't used yet
+                }
+                out = openFileOutput(randomString, MODE_PRIVATE);
+            } else if (mDecryptTarget == Id.target.message) {
                 String messageData = mMessage.getText().toString();
                 in = new PositionAwareInputStream(new ByteArrayInputStream(messageData.getBytes()));
                 out = new ByteArrayOutputStream();
                 size = messageData.getBytes().length;
             } else {
                 if (mInputFilename.startsWith("content")) {
-                    InputStream tmp = getContentResolver().openInputStream(Uri.parse(mInputFilename));
+                    size = Apg.getLengthOfStream(getContentResolver().openInputStream(Uri.parse(mInputFilename)));
-                    size = 0;
-                    long n = 0;
-                    byte dummy[] = new byte[0x10000];
-                    while ((n = tmp.read(dummy)) > 0) {
-                        size += n;
-                    }
                     in = new PositionAwareInputStream(
                             getContentResolver().openInputStream(Uri.parse(mInputFilename)));
                 } else {
@@ -528,7 +548,10 @@ public class DecryptActivity extends BaseActivity {
             }
 
             out.close();
-            if (mDecryptTarget == Id.target.message) {
+
+            if (randomString != null) {
+                data.putString(Apg.EXTRA_RESULT_URI, "content://" + DataProvider.AUTHORITY + "/data/" + randomString);
+            } else if (mDecryptTarget == Id.target.message) {
                 data.putString(Apg.EXTRA_DECRYPTED_MESSAGE,
                                new String(((ByteArrayOutputStream) out).toByteArray()));
             }
@@ -570,6 +593,14 @@ public class DecryptActivity extends BaseActivity {
         }
 
         Toast.makeText(this, R.string.decryptionSuccessful, Toast.LENGTH_SHORT).show();
+        if (mReturnResult) {
+            Intent intent = new Intent();
+            intent.putExtras(data);
+            setResult(RESULT_OK, intent);
+            finish();
+            return;
+        }
+
         switch (mDecryptTarget) {
             case Id.target.message: {
                 String decryptedMessage = data.getString(Apg.EXTRA_DECRYPTED_MESSAGE);
@@ -616,13 +647,6 @@ public class DecryptActivity extends BaseActivity {
             }
             mSignatureLayout.setVisibility(View.VISIBLE);
         }
-
-        if (mReturnResult) {
-            Intent intent = new Intent();
-            intent.putExtras(data);
-            setResult(RESULT_OK, intent);
-            finish();
-        }
     }
 
     @Override

src/org/thialfihar/android/apg/provider/DataProvider.java

@@ -16,6 +16,8 @@
 
 package org.thialfihar.android.apg.provider;
 
+import java.io.File;
+import java.io.FileNotFoundException;
 import java.util.HashMap;
 
 import org.thialfihar.android.apg.Id;
@@ -27,6 +29,7 @@ import android.database.Cursor;
 import android.database.DatabaseUtils;
 import android.database.sqlite.SQLiteQueryBuilder;
 import android.net.Uri;
+import android.os.ParcelFileDescriptor;
 import android.text.TextUtils;
 
 public class DataProvider extends ContentProvider {
@@ -50,6 +53,8 @@ public class DataProvider extends ContentProvider {
     private static final int SECRET_KEY_RING_USER_ID = 221;
     private static final int SECRET_KEY_RING_USER_ID_RANK = 222;
 
+    private static final int DATA_STREAM = 301;
+
     private static final String PUBLIC_KEY_RING_CONTENT_DIR_TYPE =
             "vnd.android.cursor.dir/vnd.thialfihar.apg.public.key_ring";
     private static final String PUBLIC_KEY_RING_CONTENT_ITEM_TYPE =
@@ -109,6 +114,8 @@ public class DataProvider extends ContentProvider {
 
         mUriMatcher.addURI(AUTHORITY, "key_rings/secret", SECRET_KEY_RING);
         mUriMatcher.addURI(AUTHORITY, "key_rings/secret/*", SECRET_KEY_RING_ID);
+
+        mUriMatcher.addURI(AUTHORITY, "data/*", DATA_STREAM);
     }
 
     @Override
@@ -360,4 +367,15 @@ public class DataProvider extends ContentProvider {
         // not supported
         return 0;
     }
+
+    @Override
+    public ParcelFileDescriptor openFile(Uri uri, String mode) throws FileNotFoundException {
+        int match = mUriMatcher.match(uri);
+        if (match != DATA_STREAM) {
+            throw new FileNotFoundException();
+        }
+        String fileName = uri.getPathSegments().get(1);
+        File file = new File(getContext().getFilesDir().getAbsolutePath(), fileName);
+        return ParcelFileDescriptor.open(file, ParcelFileDescriptor.MODE_READ_ONLY);
+    }
 }