selabel_db(5) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | OPTIONS | FILES | Object Name String Values | FILE FORMAT | NOTES | SEE ALSO | COLOPHON

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 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 "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".

              SELABEL_DB_EXCEPTION
                     The object_name argument specifies the name of a
                     exception object.

              SELABEL_DB_DATATYPE
                     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:

              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         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:
              /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         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

       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         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 found at 
       ⟨https://github.com/SELinuxProject/selinux/wiki⟩.  If you have a
       bug report for this manual page, see
       ⟨https://github.com/SELinuxProject/selinux/wiki/Contributing⟩.
       This page was obtained from the project's upstream Git repository
       ⟨https://github.com/SELinuxProject/selinux⟩ on 2021-04-01.  (At
       that time, the date of the most recent commit that was found in
       the repository was 2021-03-18.)  If you discover any rendering
       problems in this HTML version of the page, or you believe there
       is a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to
       man-pages@man7.org

Security Enhanced Linux        01 DEC 2011                 selabel_db(5)

Pages that refer to this page: selabel_open(3)