Ubuntu Manpage: pam_winbind - PAM module for Winbind

Provided by: libpam-winbind_4.15.13+dfsg-0ubuntu0.20.04.8_amd64

NAME

       pam_winbind - PAM module for Winbind

DESCRIPTION

       This tool is part of the samba(7) suite.

       pam_winbind is a PAM module that can authenticate users against the local domain by
       talking to the Winbind daemon.

SYNOPSIS

       Edit the PAM system config /etc/pam.d/service and modify it as the following example
       shows:

                              ...
                              auth      required        pam_env.so
                              auth      sufficient      pam_unix2.so
                          +++ auth      required        pam_winbind.so  use_first_pass
                              account   requisite       pam_unix2.so
                          +++ account   required        pam_winbind.so  use_first_pass
                          +++ password  sufficient      pam_winbind.so
                              password  requisite       pam_pwcheck.so  cracklib
                              password  required        pam_unix2.so    use_authtok
                              session   required        pam_unix2.so
                          +++ session   required        pam_winbind.so
                              ...

       Make sure that pam_winbind is one of the first modules in the session part. It may
       retrieve kerberos tickets which are needed by other modules.

OPTIONS

pam_winbind supports several options which can either be set in the PAM configuration
files or in the pam_winbind configuration file situated at /etc/security/pam_winbind.conf.
Options from the PAM configuration file take precedence to those from the configuration
file. See pam_winbind.conf(5) for further details.

debug
Gives debugging output to syslog.

debug_state
Gives detailed PAM state debugging output to syslog.

require_membership_of=[SID or NAME]
If this option is set, pam_winbind will only succeed if the user is a member of the
given SID or NAME. A SID can be either a group-SID, an alias-SID or even an user-SID.
It is also possible to give a NAME instead of the SID. That name must have the form:
MYDOMAIN\mygroup or MYDOMAIN\myuser (where '\' character corresponds to the value of
winbind separator parameter). It is also possible to use a UPN in the form user@REALM
or group@REALM. pam_winbind will, in that case, lookup the SID internally. Note that
NAME may not contain any spaces. It is thus recommended to only use SIDs. You can
verify the list of SIDs a user is a member of with wbinfo --user-sids=SID.

This option must only be specified on a auth module declaration, as it only operates
in conjunction with password authentication.

use_first_pass
By default, pam_winbind tries to get the authentication token from a previous module.
If no token is available it asks the user for the old password. With this option,
pam_winbind aborts with an error if no authentication token from a previous module is
available.

try_first_pass
Same as the use_first_pass option (previous item), except that if the primary password
is not valid, PAM will prompt for a password.

use_authtok
Set the new password to the one provided by the previously stacked password module. If
this option is not set pam_winbind will ask the user for the new password.

try_authtok
Same as the use_authtok option (previous item), except that if the new password is not
valid, PAM will prompt for a password.

krb5_auth
pam_winbind can authenticate using Kerberos when winbindd is talking to an Active
Directory domain controller. Kerberos authentication must be enabled with this
parameter. When Kerberos authentication can not succeed (e.g. due to clock skew),
winbindd will fallback to samlogon authentication over MSRPC. When this parameter is
used in conjunction with winbind refresh tickets, winbind will keep your Ticket
Granting Ticket (TGT) up-to-date by refreshing it whenever necessary.

krb5_ccache_type=[type]
When pam_winbind is configured to try kerberos authentication by enabling the
krb5_auth option, it can store the retrieved Ticket Granting Ticket (TGT) in a
credential cache. The type of credential cache can be controlled with this option. The
supported values are: KCM or KEYRING (when supported by the system's Kerberos library
and operating system), FILE and DIR (when the DIR type is supported by the system's
Kerberos library). In case of FILE a credential cache in the form of /tmp/krb5cc_UID
will be created - in case of DIR you NEED to specify a directory which must exist, the
UID directory will be created in the specified directory. In all cases UID is replaced
with the numeric user id. Check the details of the Kerberos implementation.

When using the KEYRING type, the supported mechanism is “KEYRING:persistent:UID”,
which uses the Linux kernel keyring to store credentials on a per-UID basis. KEYRING
has limitations. For example, it is secure kernel memory, so bulk storage of
credentials is not possible.

When using the KCM type, the supported mechanism is “KCM:UID”, which uses a Kerberos
credential manager to store credentials on a per-UID basis similar to KEYRING. This is
the recommended choice on latest Linux distributions that offer a Kerberos Credential
Manager. If not, we suggest to use KEYRING, as those are the most secure and
predictable method.

It is also possible to define custom filepaths and use the "%u" pattern in order to
substitute the numeric user id. Examples:

krb5_ccache_type = DIR:/run/user/%u/krb5cc
This will create a credential cache file in the specified directory.

krb5_ccache_type = FILE:/tmp/krb5cc_%u
This will create a credential cache file.

Leave empty to just do kerberos authentication without having a ticket cache after the
logon has succeeded. This setting is empty by default.

cached_login
Winbind allows one to logon using cached credentials when winbind offline logon is
enabled. To use this feature from the PAM module this option must be set.

silent
Do not emit any messages.

mkhomedir
Create homedirectory for a user on-the-fly, option is valid in PAM session block.

warn_pwd_expire
Defines number of days before pam_winbind starts to warn about passwords that are
going to expire. Defaults to 14 days.

PAM DATA EXPORTS

       This section describes the data exported in the PAM stack which could be used in other PAM
       modules.

       PAM_WINBIND_HOMEDIR
           This is the Windows Home Directory set in the profile tab in the user settings on the
           Active Directory Server. This could be a local path or a directory on a share mapped
           to a drive.

       PAM_WINBIND_LOGONSCRIPT
           The path to the logon script which should be executed if a user logs in. This is
           normally a relative path to the script stored on the server.

       PAM_WINBIND_LOGONSERVER
           This exports the Active Directory server we are authenticating against. This can be
           used as a variable later.

       PAM_WINBIND_PROFILEPATH
           This is the profile path set in the profile tab in the user settings. Normally the
           home directory is synced with this directory on a share.

VERSION

       This man page is part of version 4.15.13-Ubuntu of Samba.

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.

       This manpage was written by Jelmer Vernooij and Guenther Deschner.