Skip to main content

XPages and Java security troubles

This is more a rant than classic post, but I hope it may help someone or someone could prove me wrong, which would be even better.

In recent app I use  XPages Scaffolding from Jesse Gallagher. He does some magic in his code that relies on Java reflection to access classes that you can define in your NSF as your model. As my dev server had Java AllPermission grant in global block of java.policy everything worked just fine. But just until I moved the app to production server, where this setting is not possible.

I started to get Exceptions like:
java.lang.SecurityException: not allowed to access members in class 
class model.Problem
lotus.notes.AgentSecurityManager.checkMemberAccess(Unknown Source)
java.lang.Class.checkMemberAccess(Class.java:123)
java.lang.Class.getDeclaredFields(Class.java:601)
frostillicus.xsp.model.AbstractModelObject.getGenericType(AbstractMo
delObject.java:215)
frostillicus.xsp.model.domino.AbstractDominoModel.setValueImmediate
(AbstractDominoModel.java:271)
frostillicus.xsp.model.domino.AbstractDominoModel.initFromDatabase
(AbstractDominoModel.java:64)
model.Problem.initFromDatabase(Problem.java:56)

The stack trace shows that  the exception is thrown from internal Notes class that tries to enforce security.

I still thought that is is not a big deal, since I'm allowed to modify java.policy on this server, so I would just grant correct permission to my app using grant codeBase "xspnsf://" syntax. But it just don't work. I checked XPages Portable Command Guide and other sources to see if I spelled it correctly. I tried to debug the code and validate the permission in code, it just looked OK. But it had no impact on the exception. Than I found a note in release notes of Threads and Jobs project.
Note that the following does not work since the Java code is put as class in NSF as opposed to a jar file in the/lib directory:
grant codeBase "xspnsf://server:0/threadsjob.nsf/-" {
   permission java.security.AllPermission;
};
I'm not willing to put my code into a jar as it would make development much harder, so I had to look for another solution.

The problem is caused by using some reflection calls between classes that are loaded by different classloaders. To kill this check you have to play games with SecurityManager and currentClassLoader() . So I decided to use AccessController.doPriviledges and wrap all code that caused my troubles into PrivilegedActions.

It is not the nicest solution for code readability, but it solved my problem and I can continue to focus on my app and not fighting with the platform. 

It took me couple hours to solve this issue and if anyone uses Scaffolding and has similar problem, you can try to use my fork, where these changes are implemented - https://github.com/mpradny/XPages-Scaffolding/tree/feature/priviledged (code probably needs some refactoring, since this is still first version that worked)

If anyone can show me that java.policy setting for a nsf could solve this problems, let me know. I have seen many posts on Stackoverflow where people couldn't get it to work and probably just ended up with AllPermission in global block.

Comments

Popular posts from this blog

Microsoft Word black box in numbering issue

This is awkward post, primarily to save the solution for future me. I have seen many people mentioning this problem over years and as I've struggled with it several times, I needed to find final and permanent solution.


All editions of Microsoft Word from time to time suffer from bug in numbering. Instead of a number, black box is displayed. Sometimes it happens right after document is opened, sometimes during editing. Probably some internal structure of document gets corrupted, so based on level of corruption, different fixes could help. Many of them are listed at https://answers.microsoft.com/en-us/office/forum/office_2010-word/ms-word-header-styles-are-showing-black-boxes/c427b21c-dcda-46ce-a506-b9a16c9f2f3f


I took different approach. Since docx is just standard zip package with xml files, I decided to try if I can fix it manually. And it worked.

When I extracted the docx, there was file called numbering.xml in word folder. When I examined that file, I found strange section in h…

Using JAX-RS inside NSF

Last week Christian G├╝demann published new release of SmartNSF on OpenNTF that contains cool new feature that Christian tweeted before. With new CUSTOM strategy it allows direct execution
of Java code from REST API defined in router configuration. It's even better than it sounds as it initializes facesContext and XPages application if needed, so even access to beans works.

I needed to start to build new REST APIs for few databases, so I decided to test new SmartNSF option and also other available options for REST APIs on Domino (there are several, check references at the end for more info). Since CUSTOM strategy requires dependency on SmatNSF in NSF project and also implementation of CustomRestHandler interface, it'd force me to do more changes in my code that I wanted to. If I need to change my code, why not adjust it for JAX-RS spec anyway.

Existing Domino JAX-RS options had to packaged as plugins, which make it hard to call code that is currently in NSF. I could make it wor…

WSL, HCL Volt and some Docker

My list of new technologies to try was growing fast in past months, but now I finally can try to catch up with all the cool improvements that can be used to enhance my/your dev experience.
Microsoft has enhanced the Windows Subsystem for Linux this year and Docker completely changed the way Docker Desktop for Windows is integrated into the operating system. The most important change for me was that I can finally run Docker Desktop and VMWare Workstation on my machine in parallel. When I was looking for some good use cases to try how it works, HCL Domino was a logical choice. HCL started to even publish official Docker images for every release and some pre-releases are only available as Docker images. I have many test Domino machines running in VMs, but I had no HCL Volt. If you don't know that HCL Volt is - it's a new low-code platform that brings HCL Form Builder experience, now know as HCL Leap, to HCL Domino, which then serves as a data store and application server. When I…