idmap_rid - Samba's idmap_rid Backend for Winbind
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.
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. A good value for the base_rid can be 1000, since user RIDs by
default start at 1000 (512 hexadecimal).
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.
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.
security = domain
workgroup = MAIN
idmap backend = tdb
idmap uid = 1000000-1999999
idmap gid = 1000000-1999999
idmap config MAIN : backend = rid
idmap config MAIN : range = 10000 - 49999
idmap config TRUSTED : backend = rid
idmap config TRUSTED : range = 50000 - 99999
idmap config TRUSTED : base_rid = 1000
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.