PAM_WINBIND(8) 8 PAM_WINBIND(8)

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.

SEE ALSO

pam_winbind.conf(5), wbinfo(1), winbindd(8), smb.conf(5)

VERSION

This man page is part of version 4.18.11 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.

Samba 4.18.11 03/13/2024 PAM_WINBIND(8)