[refpolicy] [RFC] Security policy reworks for SE-PostgreSQL

KaiGai Kohei kaigai at ak.jp.nec.com
Mon Apr 20 18:27:27 CDT 2009


Christopher J. PeBenito wrote:
> On Mon, 2009-04-06 at 11:15 +0900, KaiGai Kohei wrote:
>> The attached patch provides some of reworks and bugfuxes
>> except for new object classes and permissions.
>>
>> - rework: Add a comment of "not currently in use" for deprecated
>>   permissions, but its definitions are not removed.
> 
> "deprecated" should be sufficient.

OK

>> - rework: All the newly created database objects by unprivileged
>>   clients are prefixed with "user_", and these are controled via
>>   sepgsql_enable_users_ddl.
> 
> I don't think we should be mixing user content with other unpriv
> clients.

I would like to discriminate between a procedure declared by unpriv
client and by administrative client, because the policy allows the
unprefixed "sepgsql_proc_exec_t" to be installed as a system internal
component, but it is undesirable to install unpriv-user defined
procedures as is.

If the "user_" prefix is unpreferable, how do you think other prefixes
something like "anon_", "unpriv_" and so on?

>>   The current policy allows httpd_t to created a function labeled
>>   as sepgsql_proc_t which is also allowed to be installed as a
>>   system internal entity (db_procedure:{install}).
>>   It is a potentially risk for trojan horse.
>>
>> - rework: postgresql_role() shares most part of postgresql_unpriv_client().
> 
> See above comment.
> 
>> - bugfix: some of permissions in db_procedure class are allowed
>>   on sepgsql_trusted_proc_t, but it is a domain, not a procedure.
>>   It should allow them on sepgsql_trusted_proc_exec_t.
>>   I also aliased sepgsql_proc_t as sepgsql_proc_exec_t to avoid
>>   such kind of confusion, as Chris suggested before.
>>
>> - rework: we should not allow db_procedure:{install} on the
>>   sepgsql_trusted_proc_exec_t, because of a risk to invoke trusted
>>   procedure implicitly.
>>
>> - rework: db_table:{lock} is moved to reader side, because it makes
>>   impossible to refer read-only table with foreign-key constraint.
>>   (FK checks internally acquire explicit locks.)
>>
>> - bugfix: MLS policy dealt db_blob:{export} as writer-side permission,
>>   but it is required whrn the largeobject is refered.
>>
>> - bugfix: MLS policy didn't constrain the db_procedure class.
> 
> Seems ok.
> 
> It would be helpful to break up the patch into a set to make it easier
> to review in the future.

OK,

Thanks,
-- 
OSS Platform Development Division, NEC
KaiGai Kohei <kaigai at ak.jp.nec.com>


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