From: cpebenito@tresys.com (Christopher J. PeBenito)
Date: Tue, 22 Feb 2011 10:46:41 -0500
Subject: [refpolicy] [patch 1/3] Implementation of system conf type
In-Reply-To: <1298319075.11119.3.camel@tesla.lan>
References: <4D5E95C1.9080805@redhat.com>
	<20110219095711.GA6270@siphos.be>	<1298180267.3098.11.camel@tesla.lan>
	<4D62875A.8060006@redhat.com> <1298319075.11119.3.camel@tesla.lan>
Message-ID: <4D63DA61.3050705@tresys.com>
To: refpolicy@oss.tresys.com
List-Id: refpolicy.oss.tresys.com

On 02/21/11 15:11, Guido Trentalancia wrote:
> On Mon, 21/02/2011 at 10.40 -0500, Daniel J Walsh wrote:
>> On 02/20/2011 12:37 AM, Guido Trentalancia wrote:
>>> On Sat, 19/02/2011 at 10.57 +0100, Sven Vermeulen wrote:
>>>> On Fri, Feb 18, 2011 at 03:52:33PM +0000, Miroslav Grepl wrote:
>>>>> http://mgrepl.fedorapeople.org/F15/system_conf_implemantion_p1.patch
>>>>>
>>>>>      * Implementation of system conf type for manageable system 
>>>>> configuration files.
>>>>
>>>> Isn't a generic system configuration type a bit too broad for a security
>>>> policy? We already have etc_t.
>>>
>>> I agree with Sven, it appears to be rather useless (at least for the use
>>> that is being made so far in the patches that have been posted) and it
>>> just introduces a redundancy of types.
>>>
>>> But Sven, I believe this is stuff just intended for Fedora 15. It won't
>>> affect the rest of us. I don't even understand why it has been posted
>>> with the [PATCH] tag in the subject on this mailing list. Some stuff
>>> won't even build on refpolicy because there are missing bits (such as
>>> missing interfaces that have never been defined in refpolicy and that
>>> are only being used by Fedora as part of their customisations).
>>>
>>
>> When you have a type a domain needs to write, you do not want that type
>> to be etc_t.  In this case several confined domains needs to be able to
>> write firewall rules, I believe.  If we give tools like
>> system-config-firewall the ability to write etc_t, it can replace
>> /etc/passwd and other key config files.  So an exploit can be used to
>> take over the entire machine, if we add a new type, then
>> system-config-firewall will only be allowed to write firewall rules and
>> not most files within the /etc tree.

I am against system_conf_t as it is too generic.  Yes, we'd like to curb
writing to etc_t.  But creating another generic type is not the answer.
 In a year or two, we'd be in the same boat except with system_conf_t
instead of (or maybe in addition to) etc_t.

I don't understand why system-config-firewall would need to write to
etc_t, the iptables rules have their own labeling:

/etc/sysconfig/ip6?tables.*     --
gen_context(system_u:object_r:iptables_conf_t,s0)
/etc/sysconfig/system-config-firewall.* --
gen_context(system_u:object_r:iptables_conf_t,s0)

> Yes, this is very important. But isn't etc_runtime_t what is needed here
> then ?

No, the purpose of that type is for generated files such as /.autofsck
and /etc/motd.



-- 
Chris PeBenito
Tresys Technology, LLC
www.tresys.com | oss.tresys.com