Shutdown issues

Shutdown issues

[Justin Smith]

I am using Redhat 7.2 with the current version of SELinux (2.4.17
kernel) and have noticed some "issues" (sorry to introduce Microsoftese)
involving shutdown:

There are a number of access denied messages in shutdown that are hard
to catch because they don't appear on the message log (since the system
is shutting down).

In some cases, software (postgres and ipchains, for instance) is not
properly shut down due to these denials. 

I don't know whether this is related, but I get a kernel panic when
shutting down in enforcing mode. It's hard to note the details of this
problem because the system succeeds in shutting down anyway (so the
messages disappear from the screen). I just recall the phrase 'kernel
panic' appearing briefly. This is only a problem for my home computer
since it shut it down after every use.

In general, I solve all of these problems by using a shutdown script
that puts the system in permissive mode just before shutdown (this is
not a security problem since it's hard to hack a system that is shutting
down...)
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Re: Shutdown issues

[Shaun Savage]

There are two ways to fix this problem,
Easy:
	just toggle out of enforcing mode sometime during shutdown.
Hard:
	 move the shutdown of the syslog to later and try to capture the 
messages, then fix it.  Or you can via sysadm role shut down just the 
services.  The problem here is sysadm_t != initrc_t.  you have to do a 
runs as.  Also even with enforcing off you get messages.

Shaun


Justin Smith wrote:

> I am using Redhat 7.2 with the current version of SELinux (2.4.17
> kernel) and have noticed some "issues" (sorry to introduce Microsoftese)
> involving shutdown:
> 
> There are a number of access denied messages in shutdown that are hard
> to catch because they don't appear on the message log (since the system
> is shutting down).
> 
> In some cases, software (postgres and ipchains, for instance) is not
> properly shut down due to these denials. 
> 
> I don't know whether this is related, but I get a kernel panic when
> shutting down in enforcing mode. It's hard to note the details of this
> problem because the system succeeds in shutting down anyway (so the
> messages disappear from the screen). I just recall the phrase 'kernel
> panic' appearing briefly. This is only a problem for my home computer
> since it shut it down after every use.
> 
> In general, I solve all of these problems by using a shutdown script
> that puts the system in permissive mode just before shutdown (this is
> not a security problem since it's hard to hack a system that is shutting
> down...)
> 




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Re: Shutdown issues

[Stephen Smalley]

On Thu, 24 Jan 2002, Shaun Savage wrote:

> Or you can via sysadm role shut down just the
> services.  The problem here is sysadm_t != initrc_t.  you have to do a
> runs as.

You can use run_init to run any of the init scripts in the proper security
context.  So, you can use run_init to shut down the services manually
while the system is still logging to a file.

--
Stephen D. Smalley, NAI Labs
ssmalley@nai.com





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Re: Shutdown issues

[Stephen Smalley]

On 24 Jan 2002, Justin Smith wrote:

> In some cases, software (postgres and ipchains, for instance) is not
> properly shut down due to these denials.

Try shutting them down manually via run_init on their init scripts with
the 'stop' command, and see what denials get logged.  There is no postgres
domain in the example policy, so I don't know what the issue might be
there.  The ipchains domain was contributed, and it doesn't look complete
to me - I would have granted the entire 'create_socket_perms' macro for
rawip_socket rather than just create and setopt.

--
Stephen D. Smalley, NAI Labs
ssmalley@nai.com




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