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On 12/10/2010 10:49 AM, KaiGai Kohei wrote: The attached patch adds a few database object classes, as follows: * db_schema ------------ A schema object performs as a namespace in database; similar to directories in filesystem. It seems some of (but not all) database objects are stored within a certain schema logically. We can qualify these objects using schema name. For example, a table: "my_tbl" within a schema: "my_scm" is identified by "my_scm.my_tbl". This table is completely different from "your_scm.my_tbl" that it a table within a schema: "your_scm". Its characteristics is similar to a directory in filesystem, so it has similar permissions. The 'search' controls to resolve object name within a schema. The 'add_name' and 'remove_name' controls to add/remove an object to/from a schema. See also, http://developer.postgresql.org/pgdocs/postgres/sql-createschema.html In the past discussion, a rubix folks concerned about no object class definition for schema and catalog which is an upper level namespace. Since I'm not certain whether we have a disadvantage when 'db_schema' class is applied on catalog class, I don't add this definition yet. From my point of view, as a rubix folk, I see no disadvantage in using the db_schema class for catalogs. As we are now overloading the dir object class, using the db_schema for both schemata and catalogs is an improvement. For us in the foreseeable future, there is no functional distinction. I do think that the SQL spec does allow things to be associated with a named schema that may not be associated with a catalog. For instance, a character set. But, don't quote me on that:-) Forgive me for my ignorance, but when a patch like this is submitted to the refpolicy, will it eventually make it into Fedora and/or RHEL 6? Default security context of 'db_table' and 'db_procedure' classes get being computed using type_transition with 'db_schema' class, instead of 'db_database' class. It reflects logical hierarchy of database object more correctly. * db_view ---------- A view object performs as a virtual table. We can run SELECT statement on views, although it has no physical entities. The definition of views are expanded in run-time, so it allows us to describe complex queries with keeping readability. This object class uniquely provides 'expand' permission that controls whether user can expand this view, or not. The default security context shall be computed by type transition rule with a schema object that owning the view. See also, http://developer.postgresql.org/pgdocs/postgres/sql-createview.html * db_sequence -------------- A sequence object is a sequential number generator. This object class uniquely provides 'get_value', 'next_value' and 'set_value' permissions. The 'get_value' controls to reference the sequence object. The 'next_value' controls to fetch and increment the value of sequence object. The 'set_value' controls to set an arbitrary value. The default security context shall be computed by type transition rule with a schema object that owning the sequence. See also, http://developer.postgresql.org/pgdocs/postgres/sql-createsequence.html * db_language -------------- A language object is an installed engine to execute procedures. PostgreSQL supports to define SQL procedures using regular script languages; such as Perl, Tcl, not only SQL or binary modules. In addition, v9.0 or later supports DO statement. It allows us to execute a script statement on server side without defining a SQL procedure. It requires to control whether user can execute DO statement on this language, or not. This object class uniquely provides 'implement' and 'execute' permissions. The 'implement' controls whether a procedure can be implemented with this language, or not. So, it takes security context of the procedure as subject. The 'execute' controls to execute code block using DO statement. The default security context shall be computed by type transition rule with a database object, because it is not owned by a certain schema. In the default policy, we provide two types: 'sepgsql_lang_t' and 'sepgsql_safe_lang_t' that allows unpriv users to execute DO statement. The default is 'sepgsql_leng_t'. We assume newly installed language may be harm, so DBA has to relabel it explicitly, if he want user defined procedures using the language. See also, http://developer.postgresql.org/pgdocs/postgres/sql-createlanguage.html http://developer.postgresql.org/pgdocs/postgres/sql-do.html P.S) I found a bug in MCS. It didn't constraint 'relabelfrom' permission of 'db_procedure' class. IIRC, I fixed it before, but it might be only MLS side. Sorry. Thanks,_______________________________________________ refpolicy mailing list refpolicy@xxxxxxxxxxxxxx http://oss.tresys.com/mailman/listinfo/refpolicy |
