sepgsql_contexts(5) — Linux manual page


selabel_db(5)             SELinux API documentation            selabel_db(5)

NAME         top

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

SYNOPSIS         top

       #include <selinux/label.h>

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

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

DESCRIPTION         top

       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

       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:

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

       The object_type argument should be set to one of the following

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

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

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

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

                     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.

                     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.

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

                     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.

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

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

                     The object_name argument specifies the name of a
                     exception object.

                     The object_name argument specifies the name of a type
                     or domain object, such as postgres.public.my_type.

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

       selabel_lookup_raw(3) behaves identically to selabel_lookup(3) but
       does not perform context translation.

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

OPTIONS         top

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

                     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

FILES         top

       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:

       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         top

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

                       │object_typeText 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      │
                       │SELABEL_DB_EXCEPTION │ db_exception │
                       │SELABEL_DB_DATATYPE  │ db_datatype  │

FILE FORMAT         top

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

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

                     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.
                     The security context that will be applied to the

       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
       db_tuple       *.*.*         system_u:object_r:sepgsql_table_t:s0

NOTES         top

       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         top

       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)

COLOPHON         top

       This page is part of the selinux (Security-Enhanced Linux user-space
       libraries and tools) project.  Information about the project can be
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Security Enhanced Linux          01 DEC 2011                   selabel_db(5)