extensible credential format

[dun]

The credential format v3 is not extensible. Supporting planned new features will require a new credential format. This format should be extensible to accommodate new features and functionality without having to update to another fixed format requiring backwards-compatibility to old formats.

Planned new features include:

• embedding multiple DEKs to facilitate key rotation (support for transitioning to a new key (aka key rotation) #19)
• embedding the SELinux security context (embed SELinux security context into credential metadata #70)
• restricting credential decoding based on the origin IP address (add MUNGE_OPT_ADDR_RESTRICTION context option #71)
• supporting 64-bit time_t values (support 64-bit time_t values #88)

[wickberg]

Hey Chris -

Just curious if you had any timeframe for working towards this, or even potential interest in an external submission working towards this.

In addition to the aforementioned SELinux security context issues, I have a potential use case for embedding the username (text string) within the credential, but this is obviously blocked by the current hard-coded credential format.

• Tim

[dun]

Hey Tim. This is at the top of my list when I cycle back to munge development (in the next couple of months?). This has been a blocker on new features for me as well. I need to finish thinking through the design to make sure it supports the future plans I have in mind. As part of this work, I'm envisioning adding a function to embed/extract custom payloads specified by an integer tag, buffer, and length. I think that would support your potential use case. I'll try to set aside some time in the next couple of weeks to poke at the design and post my plans here.

[victorusu]

Dear Chris,

I have the same questions as @wickberg.
Do you have any timeframe for working towards this?

Thanks.

[dun]

@victorusu: I'm currently busy adding functionality for our new cluster. Once that's working, I'll start on the next munge release. The new credential format is needed for much of the planned functionality going forward. Is there a particular feature or functionality you're interested in?