selabel_db(5)						     SELinux API documentation						     selabel_db(5)

NAME

       selabel_db - userspace SELinux labeling interface and configuration file format for the RDBMS objects context backend.

SYNOPSIS

       int selabel_lookup(struct selabel_handle *hnd,
			  security_context_t *context,
			  const char *object_name, int object_type);

       int selabel_lookup_raw(struct selabel_handle *hnd,
			  security_context_t *context,
			  const char *object_name, int object_type);

DESCRIPTION

       The  DB	contexts  backend maps from a pair of object name and class into security contexts. It is used to find the appropriate context for
       database objects when relabeling a certain database. The returned context must be freed using freecon(3).
       selabel_lookup(3) describes the function with its return and error codes.

       The object_name should be a fully qualified name using the hierarchy of database objects. For example, the pg_class table in  the  postgres
       database and pg_catalog schema should be qualified as:
	      Bpostgres.pg_catalog.pg_class

       The NOTES section has further information on database support for namespace hierarchies.

       The object_type argument should be set to one of the following values:

	      SELABEL_DB_DATABASE
		     The object_name argument specifies the name of a database itself, such as "postgres".

	      SELABEL_DB_SCHEMA
		     The object_name argument specifies the name of a schema object, such as "postgres.public".

	      SELABEL_DB_TABLE
		     The object_name argument specifies the name of a table object, such as "postgres.public.my_table"

	      SELABEL_DB_COLUMN
		     The object_name argument specifies the name of a column object, such as "postgres.public.my_table.user_id"

	      SELABEL_DB_TUPLE
		     The  object_name  argument  specifies  the  name  of a table object which contains the tuples to be relabeled, such as "post-
		     gresql.public.my_table". Note that we have no way to identify individual tuple objects, except for WHERE clause on DML state-
		     ments, because it has no name.

	      SELABEL_DB_PROCEDURE
		     The object_name argument specifies the name of a procedure object, such as "postgres.public.my_func". Note that we don't sup-
		     port lookup of individual security contexts for procedures which have the same name but different arguments.

	      SELABEL_DB_SEQUENCE
		     The object_name argument specifies the name of a sequence object, such as "postgres.public.my_seq".

	      SELABEL_DB_BLOB
		     The object_name argument specifies the name of a large object, such as "postgres.16308".  Note that a large object  does  not
		     have a name, so it is identified by its identifier value.

	      SELABEL_DB_VIEW
		     The object_name argument specifies the name of a view object, such as "postgres.public.my_view".

	      SELABEL_DB_LANGUAGE
		     The object_name argument specifies the name of a language object, such as "postgres.public.tcl".

       Any messages generated by selabel_lookup are sent to stderr by default, although this can be changed by selinux_set_callback(3).

       selabel_lookup_raw behaves identically to selabel_lookup but does not perform context translation.

       The FILES section details the configuration files used to determine the database object context.

OPTIONS

       In addition to the global options described in selabel_open(3), this backend recognizes the following options:

	      SELABEL_OPT_PATH
		     A non-null value for this option specifies a path to a file that will be opened in lieu of the standard DB contexts file.	It
		     tries to open the specfile designed for SE-PostgreSQL as default, so if another RDBMS uses this interface, it needs  to  give
		     an explicit specfile designed for that RDBMS (see the FILES section for details).

FILES

       The database context file used to retrieve a context depends on the SELABEL_OPT_PATH parameter passed to selabel_open(3). If NULL, then the
       SELABEL_OPT_PATH value will default to the active policy database contexts location (as returned by selinux_sepgsql_context_path(3)),  oth-
       erwise the actual SELABEL_OPT_PATH value specified is used (this option must be used to support databases other than SE-PostgreSQL).

       The default database object contexts file is:
	      /etc/selinux/{SELINUXTYPE}/contexts/sepgsql_context

       Where {SELINUXTYPE} is the entry from the selinux configuration file config (see selinux_config(5)).

       The entries within the database contexts file are shown in the Object Name String Values and FILE FORMAT sections.

Object Name String Values
       The string name assigned to each object_type argument that can be present in the database contexts file are:

							  +---------------------+--------------+
							  |object_type		| Text Name    |
							  +---------------------+--------------+
							  |SELABEL_DB_DATABASE	| db_database  |
							  +---------------------+--------------+
							  |SELABEL_DB_SCHEMA	| db_schema    |
							  +---------------------+--------------+
							  |SELABEL_DB_VIEW	| db_view      |
							  +---------------------+--------------+
							  |SELABEL_DB_LANGUAGE	| db_language  |
							  +---------------------+--------------+
							  |SELABEL_DB_TABLE	| db_table     |
							  +---------------------+--------------+
							  |SELABEL_DB_COLUMN	| db_column    |
							  +---------------------+--------------+
							  |SELABEL_DB_TUPLE	| db_tuple     |
							  +---------------------+--------------+
							  |SELABEL_DB_PROCEDURE | db_procedure |
							  +---------------------+--------------+
							  |SELABEL_DB_SEQUENCE	| db_sequence  |
							  +---------------------+--------------+
							  |SELABEL_DB_BLOB	| db_blob      |
							  +---------------------+--------------+

FILE FORMAT

       Each line within the database contexts file is as follows:
	      object_type object_name context

       Where:
	      object_type
		     This is the string representation of the object type shown in the Object Name String Values section.
	      object_name
		     The key used to obtain the context based on the object_type.

		     The entry can contain '*' for wildcard matching or '?' for substitution.

		     Note that if the '*' is used, then be aware that the order of entries in the file is important. The '*' on its own is used to
		     ensure a default fallback context is assigned and should be the last entry in the object_type block.
	      context
		     The security context that will be applied to the object.

       The following example is for SE-PostgreSQL:

       # ./contexts/sepgsql_contexts file
       # object_type  object_name   context
       db_database    my_database   system_u:object_r:sepgsql_db_t:s0
       db_database    * 	    system_u:object_r:sepgsql_db_t:s0
       db_schema      *.*	    system_u:object_r:sepgsql_schema_t:s0
       db_tuple       row_low	    system_u:object_r:sepgsql_table_t:s0
       db_tuple       row_high	    system_u:object_r:sepgsql_table_t:s0:c1023
       db_tuple       *.*.*	    system_u:object_r:sepgsql_table_t:s0

NOTES

       1.  A suitable database contexts file needs to be written for the target RDBMS and the  SELABEL_OPT_PATH  option  must  be  used  in  sela-
	   bel_open(3) to load it.

       2.  The hierarchy of the namespace for database objects depends on the RDBMS, however the selabel* interfaces do not have any specific sup-
	   port for a namespace hierarchy.

	   SE-PostgreSQL has a namespace hierarchy where a database is the top level object with the schema being the next level. Under the schema
	   object there can be other types of objects such as tables and procedures. This hierarchy is supported as follows:

		  If  a  security  context  is required for "my_table" table in the "public" schema within the "postgres" database, then the sela-
		  bel_lookup parameters for object_type would be SELABEL_DB_TABLE and the object_name  would  be  "postgres.public.my_table",  the
		  security context (if available), would be returned in context.

       3.  If contexts are to be validated, then the global option SELABEL_OPT_VALIDATE must be set before calling selabel_open(3). If this is not
	   set, then it is possible for an invalid context to be returned.

SEE ALSO

       selinux(8),  selabel_open(3),  selabel_lookup(3),   selabel_stats(3),   selabel_close(3),   selinux_set_callback(3),   selinux_sepgsql_con-
       text_path(3), freecon(3), selinux_config(5)

Security Enhanced Linux 					    01 DEC 2011 						     selabel_db(5)