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Re: Disabling selinux question



On Friday 04 January 2008 06:32:27 Linus Walleij wrote:
> So every Fedora user must have these (right?):
> root      2219  0.0  0.0  12288   684 ?        S<sl 10:14   0:00 auditd
> root      2221  0.0  0.0  12200   708 ?        S<sl 10:14   0:00
> /sbin/audispd

You can turn it off if you want. :)


> What else, besides selinux, is using auditd in Fedora right now or in the
> immediate future? (Since we're a distribution we don't count theoretical
> use cases I hope...)

The audit logs are the collection point for all security relevant events from 
failed logins, to avcs, to raw sockets being opened, to apps that segfault. 
It collects everything that truly matters regarding security. It also has a 
simple utility that gives you a quick overview of security events, aureport. 
For an overview since Sunday, "aureport --start this-week"

Regarding the future, I have plans to add IDS/IPS plugin to audispd so that it 
can spot and react to suspicious events. I also plan to create a prelude 
plugin that can take events and send them to a prelude manager. 

The security audit tool that was announced yesterday will send any security 
issues it discovers to the audit system where it can be reported on. aide 
also sends a summary description of what it finds to the audit system.

If auditd is not running, these events wind up in syslog. Some people do not 
like all these events cluttering up syslog, so its simpler to just run the 
audit daemon. Sooner or later people need to research something related to 
security and the audit system has search and reporting tools.

> bash-3.2$ repoquery --whatrequires `repoquery --provides audit`
> setroubleshoot-server-0:2.0.0-3.fc9.noarch
> audispd-plugins-0:1.6.4-3.fc9.i386
> seedit-0:2.2.0-1.fc9.i386
> amtu-0:1.0.6-1.fc9.i386
> audit-0:1.6.4-3.fc9.i386
>
> auditspd-plugins, seedit and amtu are not default-installed, so on a
> Fedora default install, SELinux is really the only thing actually using
> auditd, am I right?

No, *everything* security related goes into the audit logs.


> If I read this correctly, we must have auditd running on any Fedora box
> everywhere, even without SELinux since:
>
> * auditspd-plugins may be installed and can monitor remote machines and
>    wouldn't work without auditd, so the entire network comes into the
>    picture here and it's hard for the UI to know what the user wants.
>
> * amtu may be installed, so then it is necessary to have.

Technically, amtu needs audit-libs. auditd just ensures amtu events windup in 
audit logs rather than syslog. auditd should not be required by amtu.


> As indeed if the user of system-config-services or anaconda previously
> disabled auditd, then installing the amtu or auditspd-plugins RPM will
> or should turn the service on again by some %post script or similar,
> right?

It should not. amtu is happy to send things to audit system which sees that 
auditd is not running and then forwards events to syslog for disposition.


> If this is NOT true, then the user should NOT be allowed to disable auditd
> under any circumstances, and shouldn't worry about it using a few KB of
> memory, it should have "# hide: true" added to /etc/init.d/auditd
> so it's not even shown in s-c-s right?
>
> There must be one of these things needing to have a bug filed.
>
> I could easily imagine things like AppArmour, TOMOYO or tripwire (not
> even in-kernel!) to use it in theory, though I don't know if they do in
> practice, and none of them are in Fedora, so please enlighten me if you
> know further use cases.

AppArmour does use the audit system. But we do not ship it. We have aide, not 
tripwire and it is modified. TOMOYO, I'm not familiar with, nor have they 
contacted me about reserving events. If you search on audit-libs, you will 
see the real breadth of what uses the audit system. auditdis just the 
collector, which may or may not be running or installed. All the apps need 
the audit-libs to send events to the kernel which ultimately sends events to 
the audit daemon.


> Okay!
> https://bugzilla.redhat.com/show_bug.cgi?id=427506
> (pending discussion as of whether auditd could actually be disabled too)

sigh...the services should exit if selinux is disabled. Its ok for them to 
start up.

-Steve


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