NAME

       cifs.idmap - Userspace helper for mapping ids for Common Internet File System (CIFS)

SYNOPSIS

       cifs.idmap [--help|-h] [--timeout|-t] [--version|-v] {keyid}

DESCRIPTION

       This tool is part of the cifs-utils suite.

       cifs.idmap is a userspace helper program for the linux CIFS client filesystem. There are a number of
       activities that the kernel cannot easily do itself. This program is a callout program that does these
       things for the kernel and then returns the result.

       cifs.idmap is generally intended to be run when the kernel calls request-key(8) for a particular key
       type. While it can be run directly from the command-line, it is not generally intended to be run that
       way.

       This program is only called if a share is mounted with the cifsacl mount option. The kernel will only
       upcall to do this conversion if that mount option is specified.

       cifs.idmap relies on a plugin to handle the ID mapping. If it can't find the plugin then it will not work
       properly. The plugin (or a symlink to it) must be at /etc/cifs-utils/idmap-plugin.

       In the case where cifs.idmap or the plugin are unavailable, file objects in a mounted share are assigned
       uid and gid of the credentials of the process that mounted the share. It is strongly recomemended to use
       mount options of uid and gid to specify a default uid and gid to map owner SIDs and group SIDs in this
       situation.

OPTIONS

       --help|-h
              Print the usage message and exit.

       --timeout|-t
           Set the expiration timer, in seconds on the key. The default is 600 seconds (10 minutes). Setting
           this to 0 will cause the key to never expire.

       --version|-v
           Print version number and exit.

CONFIGURATION FOR KEYCTL

       cifs.idmap is designed to be called from the kernel via the request-key callout program. This requires
       that request-key be told where and how to call this program. Currently cifs.idmap handles a key type of:

       cifs.idmap
           This keytype is for mapping a SID to either an uid or a gid

       To make this program useful for CIFS, you will need to set up entry for it in request-key.conf(5). Here
       is an example of an entry for this key type:

           #OPERATION  TYPE           D C PROGRAM ARG1 ARG2...
           #=========  =============  = = ================================
           create      cifs.idmap     * * /usr/sbin/cifs.idmap %k

       See request-key.conf(5) for more info on each field.

NOTES

       Support for upcalls to cifs.idmap was initially introduced in the 3.0 kernel.

SEE ALSO

       request-key.conf(5), mount.cifs(8)

AUTHOR

       Shirish Pargaonkar wrote the cifs.idmap program.

       The Linux CIFS Mailing list is the preferred place to ask questions regarding these programs.