IDMAP_RID(8) System Administration tools IDMAP_RID(8)

NAME

idmap_rid - Samba's idmap_rid Backend for Winbind

DESCRIPTION

The idmap_rid backend provides a way to use an algorithmic mapping
scheme to map UIDs/GIDs and SIDs. No database is required in this
case as the mapping is deterministic.

Currently, there should to be an explicit idmap configuration for
each domain that should use the idmap_rid backend, using disjoint
ranges.

NOTE: The idmap_rid backend can NOT bet used as the default backend.
One usually needs to define a writeable default idmap range, using a
backend like tdb or ldap that can create unix ids, in order to be
able to map the BUILTIN sids and other domains, and also in order to
be able to create group mappings. See the example below.

IDMAP OPTIONS

range = low - high
Defines the available matching uid and gid range for which the
backend is authoritative. Note that the range acts as a filter.
If algorithmically determined UID or GID fall outside the range,
they are ignored and the corresponding map is discarded. It is
intended as a way to avoid accidental UID/GID overlaps between
local and remotely defined IDs.

base_rid = INTEGER
Defines the base integer used to build SIDs out of a UID or a
GID, and to rebase the UID or GID to be obtained from a SID. This
means SIDs with a RID less than the base rid are filtered. The
default is not to restrict the allowed rids at all, i.e. a
base_rid value of 0.

Use of this parameter is deprecated.

THE MAPPING FORMULAS

The Unix ID for a RID is calculated this way:

ID = RID - BASE_RID + LOW_RANGE_ID.


Correspondingly, the formula for calculating the RID for a given Unix
ID is this:

RID = ID + BASE_RID - LOW_RANGE_ID.

EXAMPLES

This example shows how to configure two domains with idmap_rid, the
principal domain and a trusted domain, leaving the default id mapping
scheme at tdb. The example also demonstrates the use of the base_rid
parameter for the trusted domain.

[global]
security = domain
workgroup = MAIN

idmap config * : backend = tdb
idmap config * : range = 1000000-1999999

idmap config MAIN : backend = rid
idmap config MAIN : range = 10000 - 49999

idmap config TRUSTED : backend = rid
idmap config TRUSTED : range = 50000 - 99999

AUTHOR

The original Samba software and related utilities were created by
Andrew Tridgell. Samba is now developed by the Samba Team as an Open
Source project similar to the way the Linux kernel is developed.

Samba 4.18.11 03/13/2024 IDMAP_RID(8)