For security reasons, Corda Server can only read appearance files, data files, PCXML files, and web documents from authorized locations. Likewise, it can only write image and document files to authorized locations. By default, Corda Server can only read from its document root directory and subdirectories, and the localhost (127.0.0.1) domain. It can only write to the images folder of the document root directory.

This means that you will need to authorize any other locations that you want Corda Server to read from or write to. For example, suppose that you wanted to load a web document from a web application server located at http://webapp.mycompany.com. Corda Server would need to be given permission to retrieve data from this location. Likewise, you would need to give Corda Server permission to load an appearance file from the C:\InetPub folder on the computer running the Corda Server

You can control which locations Corda Server can read or write from by editing the path.xml file. This file is located in the config directory. You can edit it in a text editor such as Microsoft Notepad, or you can edit it in the Administration Console.

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The Need for Security

To convince you of the need for a path.xml file, and also to keep you from defeating the purpose of this file, we should point out two ways by which an insecure server can be abused.

First of all, without Corda Server built-in security settings, Corda Server's save capabilities can be used to overwrite crucial system files. For example, Corda Embedder's saveToCordaServer(String) method allows a programmer to save images for future use to the machine running the Corda Server. A hacker could easily use this method to save an image over a system file, thus crashing your server, or to save an unrestricted number of files to disk, making you run short on critical disk space.

Note: You also need to specify a password to save images to Corda Server, so this could only happen if your password were insecure.

To prevent this from occurring, the path.xml file controls the directories to which Corda Server can write files. By default, the only directory to which images and documents can be saved is the images folder inside of the document root directory. Unless you have a really good reason to add another location, you should probably leave it this way.

The second security issue is that Corda Server can read files from URLs. Although this flexibility is one of Corda Server's most attractive features, it also opens up several possibilities. First of all, it makes it possible that your server can be used for denial of service attacks, by repeatedly requesting large documents from other web servers.

Also, it opens up the possibility for parasites—outside users who use your Corda Server to generate their own Corda images. For example, suppose the webmaster for a small website decides she wants the benefits of Corda Server, but doesn't want to buy it. All this webmaster has to do is figure out the address and port that your Corda Server runs on (which is easy to discover by viewing a web page's HTML), and she would instantly be able to use it to request and generate images for her own website. Of course, our more philanthropic customers might not mind lending a few graphs and maps to the less fortunate, but most users will have a problem with this behavior.

To prevent such abuse, the path.xml file allows you to specify a list of valid callback domains. The term callback describes any requests that Corda Server makes to an outside resource for information (appearance files, data, etc.).

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Modifying path.xml

To add or remove path and URL permissions for Corda Server, you should modify the path.xml file.

To add permission to read from a specified URL

To add permission to read from a specified local path

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