Re: Comprehensive Documentation on the Linux Audit Framework

[Steve Grubb <sgrubb@redhat.com>]

On Tuesday, June 6, 2023 6:31:55 PM EDT Vincent Abraham wrote:
> Thanks. Could you also point to portions in the codebase where these
> functions are called for monitoring file access?

I'll let Richard or Paul point to the place in the kernel if that's 
necessary. I think there's a fundamental mismatch and it might not matter.

> The reason I'm asking for this is that I'm trying to provide auditing for
> files of a specific type and I'm trying to understand how would that work.

The way the audit system works is there is a rule engine in the kernel. User 
space loads the rules and and listens for events. The kernel does all the 
work. This rule matching can be done by a limited set of attributes which for 
a file would be path, kind of access, who is accessing it, program accessing 
it, portions of se linux labeling, and a few other things.

You cannot match by type or anything that looks like a glob. You can arrange 
them in a directory and watch the whole directory. You can create a script 
that looks for files of a certain type and load rules specifically for them 
into the kernel (with a specific key so you can find them later). Or you can 
plug into auditd as a plugin and filter the events and write them to your own 
log.

There might be some other approaches such as using fanotify and filtering 
those events yourself.

-Steve


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