Stephen Smalley wrote: > On Wed, 2008-05-28 at 10:13 +0900, KaiGai Kohei wrote: >> Stephen Smalley wrote: >>> On Tue, 2008-05-27 at 13:55 -0400, Christopher J. PeBenito wrote: >>>> On Tue, 2008-05-27 at 13:14 -0400, Stephen Smalley wrote: >>>>> On Mon, 2008-05-26 at 19:30 +0900, KaiGai Kohei wrote: >>>>>> Hello, >>>>>> >>>>>> The attached patch enables to obtain the default security context of newly >>>>>> created database, defined at /etc/selinux/*/contexts/postgresql_contexts . >>>>>> >>>>>> The format is as follows: >>>>>> -------- >>>>>> # >>>>>> # Config file for SE-PostgreSQL >>>>>> # >>>>>> # <domain of client> <type of newly created database> >>>>>> unconfined_t sepgsql_db_t >>>>>> * sepgsql_db_t >>>>>> -------- >>>>>> >>>>>> '*' means default security context, if given key is not matched for any entry. >>>>>> >>>>>> This API requires the security context of client as a key, and it returns >>>>>> a security context to be attached for a newly created database. >>>>>> It has a type field defined in the right-hand of config file, and inherits >>>>>> user and lower-range field of given security context as a key. >>>>>> >>>>>> e.g) >>>>>> selabel_lookup(sehandle, &context, "user_u:user_r:user_t:s0", 0); >>>>>> returns "user_u:object_r:sepgsql_db_t:s0". >>>>> Chris is investigating the use of roles on objects in order to provide >>>>> more fully featured RBAC support without requiring use of per-role >>>>> domains. Hardcoding the use of object_r won't be future compatible for >>>>> that situation, and more generally we don't want to hardcode policy >>>>> information in libselinux at all. >>>>> >>>>> I'm also unclear as to why type_transition rules aren't a better way of >>>>> expressing the above, although I know you've been discussing this with >>>>> Chris for some time. Logically I'd expect the client domain to be the >>>>> source type of the transition, and the type for the newly created >>>>> database to be the new/result type of the transition. What to use as >>>>> the target type is less clear; we'd have a similar issue if we were to >>>>> use type_transitions for e.g. sockets. It could either be the client >>>>> domain both as source and target (self relationship, no related object) >>>>> or the client domain as source and the object manager domain as target. >>>>> >>>>> Chris, what is the objection to using type transitions here, as they are >>>>> for labeling new objects and this seems to fit that situation? >>>> I think KaiGai took my idea a little to far. My issue was just to have >>>> postgres determine what the default label for its objects are via >>>> postgresql_contexts. A derived role/type still makes sense to be stated >>>> via (type|role)_transition. I suspect there was confusion on this >>>> point. I mainly had an issue with statements like: >>>> >>>> type_transition postgresql_t postgresql_t:db_database sepgsql_db_t; >>>> type_transition postgresql_t sepgsql_database_type:db_table sepgsql_sysobj_t; >>>> type_transition postgresql_t sepgsql_database_type:db_procedure sepgsql_proc_t; >>>> type_transition postgresql_t sepgsql_database_type:db_blob sepgsql_blob_t; >>>> type_transition sepgsql_client_type postgresql_t:db_database sepgsql_db_t; >>> The first four statements don't make sense to me; the last one does make >>> sense (i.e. when a postgres client creates a new database, where the >>> only related "object" in view is that object manager's context, label >>> the new database with sepgsql_db_t). That last instance seems valid as >>> a way of expressing types for new databases; the first four statements >>> seem to be more suited to this postgres contexts configuration (as they >>> are independent of client domain entirely). >> When SE-PostgreSQL initializes itself, a server process is a client process >> in same time. The first four rules are necessary to attach proper context >> of any system object on initialization. > > Hmm...in that case, type_transition makes sense for that initialization. > >> It does not means something default. >> >> In the "default" behavior, if we have no type_transition, >> - a newly created database inherits the type of server process >> - a newly created table/procedure/largeobject inherits the type of database >> - a newly created column/tuple inherits the type of table > > So is that "default" behavior fundamentally a problem? > Do we really need these other contexts at all? No, it is theoretically possible to share only one type for various object classes. (unlabeled_t can be an example for this case.) If a policy writer want, we can label all of database object with same security context and allows something for each object classes. However, it is rightly confusable policy. So, I defined object classes specific types, like sepgsql_table_t, sepgsql_proc_t, ... >>>> which I feel should be instead be expressed in a postgresql_contexts >>>> file that says the default context for a database is ::seqpgsql_db_t, >>>> default context for table is ::sepgsql_sysobj_t, etc. >>>> >>>> This makes perfect sense staying as a type_transition in the policy: >>>> >>>> type_transition staff_t sepgsql_sysobj_t:db_tuple staff_sepgsql_sysobj_t; -- KaiGai Kohei <kaigai@xxxxxxxxxxxx> -- This message was distributed to subscribers of the selinux mailing list. 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