GUACAMOLE-362: Implement new CipherGuacamoleProperty and move cipher functionality to it.

guacamole-ext/src/main/java/org/apache/guacamole/properties/CipherGuacamoleProperty.java

@@ -0,0 +1,92 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.guacamole.properties;
+
+import java.io.BufferedInputStream;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
+import java.io.InputStream;
+import java.io.IOException;
+import java.lang.IllegalArgumentException;
+import java.security.InvalidKeyException;
+import java.security.KeyFactory;
+import java.security.NoSuchAlgorithmException;
+import java.security.PrivateKey;
+import java.security.spec.InvalidKeySpecException;
+import java.security.spec.KeySpec;
+import java.security.spec.PKCS8EncodedKeySpec;
+import javax.crypto.Cipher;
+import javax.crypto.NoSuchPaddingException;
+import org.apache.guacamole.GuacamoleException;
+import org.apache.guacamole.environment.Environment;
+import org.apache.guacamole.environment.LocalEnvironment;
+
+/**
+ * A GuacamoleProperty whose value is derived from a private key file.
+ */
+public abstract class CipherGuacamoleProperty implements GuacamoleProperty<Cipher>  {
+
+    @Override
+    public Cipher parseValue(String value) throws GuacamoleException {
+
+        try {
+
+            final Environment environment = new LocalEnvironment();
+
+            // Open and read the file specified in the configuration.
+            File keyFile = new File(environment.getGuacamoleHome(), value);
+            InputStream keyInput = new BufferedInputStream(new FileInputStream(keyFile));
+            final byte[] keyBytes = new byte[(int) keyFile.length()];
+            keyInput.read(keyBytes);
+            keyInput.close();
+
+            // Set up decryption infrastructure
+            KeyFactory keyFactory = KeyFactory.getInstance("RSA");
+            KeySpec keySpec = new PKCS8EncodedKeySpec(keyBytes);
+            final PrivateKey privateKey = keyFactory.generatePrivate(keySpec);
+            final Cipher cipher = Cipher.getInstance(privateKey.getAlgorithm());
+            cipher.init(Cipher.DECRYPT_MODE, privateKey);
+
+            return cipher;
+
+        }
+        catch (FileNotFoundException e) {
+            throw new GuacamoleException("Could not find the specified key file.", e);
+        }
+        catch (IOException e) {
+            throw new GuacamoleException("Could not read in the specified key file.", e);
+        }
+        catch (NoSuchAlgorithmException e) {
+            throw new GuacamoleException("Specified algorithm does not exist.", e);
+        }
+        catch (InvalidKeyException e) {
+            throw new GuacamoleException("Specified key is invalid.", e);
+        }
+        catch (InvalidKeySpecException e) {
+            throw new GuacamoleException("Invalid KeySpec initialization.", e);
+        }
+        catch (NoSuchPaddingException e) {
+            throw new GuacamoleException("No such padding exception.", e);
+        }
+
+    }
+
+}