PAM_KRB5_MIGRATE(5)PAM_KRB5_MIGRATE(5)NAMEpam_krb5_migrate - authentication PAM module for the KerberosV5 auto-
migration of users feature
SYNOPSIS
/usr/lib/security/pam_krb5_migrate.so.1
DESCRIPTION
The KerberosV5 auto-migrate service module for PAM provides functional‐
ity for the PAM authentication component. The service module helps in
the automatic migration of PAM_USER to the client's local Kerberos
realm, using PAM_AUTHTOK (the PAM authentication token associated with
PAM_USER) as the new Kerberos principal's password.
KerberosV5 Auto-migrate Authentication Module
The KerberosV5 auto-migrate authentication component provides the
pam_sm_authenticate(3PAM) function to migrate a user who does not have
a corresponding krb5 principal account to the default Kerberos realm of
the client.
pam_sm_authenticate(3PAM) uses a host-based client service principal,
present in the local keytab (/etc/krb5/krb5.keytab) to authenticate to
kadmind(1M) (defaults to the host/nodename.fqdn service principal), for
the principal creation operation. Also, for successful creation of the
krb5 user principal account, the host-based client service principal
being used needs to be assigned the appropriate privilege on the master
KDC's kadm5.acl(4) file. kadmind(1M) checks for the appropriate privi‐
lege and validates the user password using PAM by calling pam_authenti‐
cate(3PAM) and pam_acct_mgmt(3PAM) for the k5migrate service.
If migration of the user to the KerberosV5 infrastructure is success‐
ful, the module will inform users about it by means of a PAM_TEXT_INFO
message, unless instructed otherwise by the presence of the quiet
option.
The authentication component always returns PAM_IGNORE and is meant to
be stacked in pam.conf with a requirement that it be listed below
pam_authtok_get(5) in the authentication stack. Also, if
pam_krb5_migrate is used in the authentication stack of a particular
service, it is mandatory that pam_krb5(5) be listed in the PAM account
stack of that service for proper operation (see EXAMPLES).
OPTIONS
The following options can be passed to the KerberosV5 auto-migrate
authentication module:
debug
Provides syslog(3C) debugging information at LOG_DEBUG level.
client_service=<service name>
Name of the service used to authenticate to kadmind(1M) defaults to
host. This means that the module uses host/<nodename.fqdn> as its
client service principal name, KerberosV5 user principal creation
operation or <service>/<nodename.fqdn> if this option is provided.
quiet
Do not explain KerberosV5 migration to the user.
This has the same effect as passing the PAM_SILENT flag to
pam_sm_authenticate(3PAM) and is useful where applications cannot
handle PAM_TEXT_INFO messages.
If not set, the authentication component will issue a PAM_TEXT_INFO
message after creation of the Kerberos V5 principal, indicating
that it has done so.
expire_pw
Causes the creation of KerberosV5 user principals with password
expiration set to now (current time).
EXAMPLES
Example 1 Sample Entries from pam.conf
The following entries from pam.conf(4) demonstrate the use of the
pam_krb5_migrate.so.1 module:
login auth requisite pam_authtok_get.so.1
login auth required pam_dhkeys.so.1
login auth required pam_unix_cred.so.1
login auth sufficient pam_krb5.so.1
login auth requisite pam_unix_auth.so.1
login auth optional pam_krb5_migrate.so.1 expire_pw
login auth required pam_dial_auth.so.1
other account requisite pam_roles.so.1
other account required pam_krb5.so.1
other account required pam_unix_account.so.1
The pam_krb5_migrate module can generally be present on the authentica‐
tion stack of any service where the application calls pam_sm_authenti‐
cate(3PAM) and an authentication token (in the preceding example, the
authentication token would be the user's Unix password) is available
for use as a Kerberos V5 password.
Example 2 Sample Entries from kadm5.acl
The following entries from kadm5.acl(4) permit or deny privileges to
the host client service principal:
host/*@ACME.COM U root
host/*@ACME.COM ui *
The preceding entries permit the pam_krb5_migrate add privilege to the
host client service principal of any machine in the ACME.COM KerberosV5
realm, but denies the add privilege to all host service principals for
addition of the root user account.
Example 3 Sample Entries in pam.conf of the Master KDC
The entries below enable kadmind(1M) on the master KDC to use the
k5migrate PAM service in order to validate Unix user passwords for
accounts that require migration to the Kerberos realm.
k5migrate auth required pam_unix_auth.so.1
k5migrate account required pam_unix_account.so.1
ATTRIBUTES
See attributes(5) for a description of the following attribute:
┌────────────────────┬─────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├────────────────────┼─────────────────┤
│Interface Stability │ Evolving │
└────────────────────┴─────────────────┘
SEE ALSOkadmind(1M), syslog(3C), pam_authenticate(3PAM), pam_acct_mgmt(3PAM),
pam_sm_authenticate(3PAM), kadm5.acl(4), pam.conf(4), attributes(5),
pam_authtok_get(5), pam_krb5(5)
Jul 29, 2004 PAM_KRB5_MIGRATE(5)
