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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | FILES | Object Name String Values | FILE FORMAT | NOTES | SEE ALSO | COLOPHON |
selabel_db(5) SELinux API documentation selabel_db(5)
selabel_db - userspace SELinux labeling interface and configuration
file format for the RDBMS objects context backend
#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);
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.
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).
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.
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 │
├─────────────────────┼──────────────┤
│SELABEL_DB_EXCEPTION │ db_exception │
├─────────────────────┼──────────────┤
│SELABEL_DB_DATATYPE │ db_datatype │
└─────────────────────┴──────────────┘
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
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.
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)
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 2017-07-05. 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)