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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 backendSYNOPSIS¶
#include <selinux/label.h> int selabel_lookup(struct selabel_handle *hnd,char **context,
int selabel_lookup_raw(struct selabel_handle *hnd,
char **context,
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).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 "postgresql.public.my_table". Note that we have no way to identify individual tuple objects, except for WHERE clause on DML statements, 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 support 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".
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)), otherwise 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
The following example is for SE-PostgreSQL:
# ./contexts/sepgsql_contexts file
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.
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 selabel_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 support 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
selabel_lookup(3) 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_context_path(3), freecon(3), selinux_config(5)01 DEC 2011 | Security Enhanced Linux |