Commit fbdcd0b8 authored by Daniel W. S. Almeida's avatar Daniel W. S. Almeida Committed by Jonathan Corbet

Documentation: nfs: idmapper: convert to ReST

Convert idmapper.txt to ReST and move it to admin-guide.
Content remains mostly unchanged otherwise.
Signed-off-by: default avatarDaniel W. S. Almeida <dwlsalmeida@gmail.com>
Link: https://lore.kernel.org/r/069e40cd551ea778538f8fe9ad15ee26e45fc748.1578697871.git.dwlsalmeida@gmail.comSigned-off-by: default avatarJonathan Corbet <corbet@lwn.net>
parent 0f3456ba
......@@ -9,3 +9,4 @@ NFS
nfsroot
nfs-rdma
nfsd-admin-interfaces
nfs-idmapper
=============
NFS ID Mapper
=============
=========
ID Mapper
=========
Id mapper is used by NFS to translate user and group ids into names, and to
translate user and group names into ids. Part of this translation involves
performing an upcall to userspace to request the information. There are two
......@@ -20,22 +20,24 @@ legacy rpc.idmap daemon for the id mapping. This result will be stored
in a custom NFS idmap cache.
===========
Configuring
===========
The file /etc/request-key.conf will need to be modified so /sbin/request-key can
direct the upcall. The following line should be added:
#OP TYPE DESCRIPTION CALLOUT INFO PROGRAM ARG1 ARG2 ARG3 ...
#====== ======= =============== =============== ===============================
create id_resolver * * /usr/sbin/nfs.idmap %k %d 600
``#OP TYPE DESCRIPTION CALLOUT INFO PROGRAM ARG1 ARG2 ARG3 ...``
``#====== ======= =============== =============== ===============================``
``create id_resolver * * /usr/sbin/nfs.idmap %k %d 600``
This will direct all id_resolver requests to the program /usr/sbin/nfs.idmap.
The last parameter, 600, defines how many seconds into the future the key will
expire. This parameter is optional for /usr/sbin/nfs.idmap. When the timeout
is not specified, nfs.idmap will default to 600 seconds.
id mapper uses for key descriptions:
id mapper uses for key descriptions::
uid: Find the UID for the given user
gid: Find the GID for the given group
user: Find the user name for the given UID
......@@ -45,23 +47,24 @@ You can handle any of these individually, rather than using the generic upcall
program. If you would like to use your own program for a uid lookup then you
would edit your request-key.conf so it look similar to this:
#OP TYPE DESCRIPTION CALLOUT INFO PROGRAM ARG1 ARG2 ARG3 ...
#====== ======= =============== =============== ===============================
create id_resolver uid:* * /some/other/program %k %d 600
create id_resolver * * /usr/sbin/nfs.idmap %k %d 600
``#OP TYPE DESCRIPTION CALLOUT INFO PROGRAM ARG1 ARG2 ARG3 ...``
``#====== ======= =============== =============== ===============================``
``create id_resolver uid:* * /some/other/program %k %d 600``
``create id_resolver * * /usr/sbin/nfs.idmap %k %d 600``
Notice that the new line was added above the line for the generic program.
request-key will find the first matching line and corresponding program. In
this case, /some/other/program will handle all uid lookups and
/usr/sbin/nfs.idmap will handle gid, user, and group lookups.
See <file:Documentation/security/keys/request-key.rst> for more information
See Documentation/security/keys/request-key.rst for more information
about the request-key function.
=========
nfs.idmap
=========
nfs.idmap is designed to be called by request-key, and should not be run "by
hand". This program takes two arguments, a serialized key and a key
description. The serialized key is first converted into a key_serial_t, and
......
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