From: kaigai@kaigai.gr.jp (KaiGai Kohei)
Date: Thu, 22 Jan 2009 07:28:55 +0900
Subject: [refpolicy] [PATCH] Add a new permission to db_procedure
In-Reply-To: <4975E9A3.8060003@kaigai.gr.jp>
References: <4973468F.1010706@kaigai.gr.jp> <49758904.2070303@ak.jp.nec.com>
	<1232461874.10460.1.camel@gorn> <4975E9A3.8060003@kaigai.gr.jp>
Message-ID: <4977A1A7.60304@kaigai.gr.jp>
To: refpolicy@oss.tresys.com
List-Id: refpolicy.oss.tresys.com

Folks,

Do you have any opinion, question, approval or opposition for the new
permission to db_procedure class?

KaiGai Kohei wrote:
>> Changes to object classes need to be discussed on the SELinux list.
> 
> OK, I send the patch again for folks in selinux-list only.
> 
>>>> The attached patch add a new permission named as "install" to db_procedure.
>>>>
>>>> The purpose of this permission is to prevent malicious functions are invoked
>>>> as a part of server's internal tasks.
>>>>
>>>> PostgreSQL allows user-defined functions to use its internal tasks.
>>>> For example, it can be used to implement an output/input handler of new data
>>>> types, an index access method, implementation of operator classes and so on.
>>>>
>>>> When we defines a new type, it requires to specify its output/input handler
>>>> at least. No need to say, these functions should not be malicious ones,
>>>> because user implicitly invokes these function when he uses the type.
>>>> This permission is checked when we defines a new system catalog entry which
>>>> has a possibility to invoke user defined functions.
> 
> A supplement:
> PostgreSQL allows user to define his own data type, like "struct xxx" in C
> language, and he can also define its input/output handler. The input/output
> handler is invoked when user send a text representation, to translate it
> into internal data structure, implicitly. For example, a function similar
> to atoi() is configured for INTEGER type in default.
> 
> I'm worrying about a malicious one secretly installs a malicious function
> which leaks given information to somewhere as a implementation of type
> input/output handler, in typical scenario.
> 
> In addition, it allows to install user-defined functions to implement
> database index access methods, multibyte encoding conversions, operator
> classes and so on.
> 
>>>> In the attached patch, only sepgsql_proc_t is allowed to { install }, because
>>>> any other user defined functions are not checked by DBA, so it is not safe to
>>>> use it as a part of internal/common processes.
>>>> If DBA want to apply user defined functions as a part of internal task, he has
>>>> to confirm its safeness and relabel to sepgsql_proc_t at first.
>>>>
>>>> Please apply it, if no matter.
> 
> Thanks,


-- 
KaiGai Kohei <kaigai@kaigai.gr.jp>