Github user mike-jumper commented on a diff in the pull request:
https://github.com/apache/incubator-guacamole-client/pull/183#discussion_r140011656
--- Diff:
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);
+ }
+
--- End diff --
> ... so instead of returning null, here, I'm throwing GuacamoleException.
Sounds good. I'm always in favor of strict error handling, though
[`GuacamoleServerException`](http://guacamole.incubator.apache.org/doc/guacamole-common/org/apache/guacamole/GuacamoleServerException.html)
may be a better choice.
> This means that, if those exceptions are thrown while CAS is using this
property, it'll kill CAS authentication if this Cipher property fails to parse
for one of these reasons. I consider that behavior less desirable than just not
having the password available to the user, as authentication has technically
still succeeded.
Is it expected that this will occasionally fail under normal (not
misconfigured) conditions? If not, I'd think the administrator would rather be
able to rely on all-or-nothing, predictable behavior, particularly if relying
on this feature.
> I suppose I could capture the GuacamoleException inside the CAS module
when pulling this property and just return null instead of allowing the
GuacamoleException to pass through...
That would depend on which is worse: having a partially-functional system,
where explicitly-enabled functionality is mysteriously non-functional, or
having a disabled system, where authentication fails entirely until everything
which has been explicitly enabled is actually functional.
---
