Hello again,
Firstly, thanks to those who have taken time to shoot an e-mail my way
to try and help. It's greatly appreciated. Secondly, sorry to be
sending out another list mail but I notice that the suggestions I got
were all more or less the same -- look at PAM. I think I may not have
been clear enough in my last e-mail, so I'll try to explain again. I
also forgot to include version numbers and attach some config files.
Again, my apologies.
Also, I don't do much in the realm of mailing lists so I'm unsure if it
is expected that most people that write in are subscribed. I happen not
to be, so please reply directly to my address if you would.
Our servers are primarily running RHEL4:
`cat /etc/issue`
Red Hat Enterprise Linux AS release 4 (Nahant Update 7)
Kernel \r on an \m
Some important lib versions (I don't think I missed any but I am far
from an expert):
`rpm -qa | grep krb5`
krb5-workstation-1.3.4-60.el4
krb5-auth-dialog-0.2-1
krb5-libs-1.3.4-60.el4
pam_krb5-2.1.17-6.el4
`rpm -q "nss_ldap"`
nss_ldap-253-5.el4
Finally, a kernel version:
`uname -r`
2.6.9-78.ELsmp
The suggestions I got via e-mail were to look at my PAM configuration.
What I was attempting to convey before was that I have indeed gone over
PAM settings and here's what I have:
I can successfully get a Kerberos ticket (it is shown in `klist` after
login) **if ldap is not listed in nsswitch.conf**. Here's a snippet to
show what I mean:
passwd: files
shadow: files
group: files
The above works. However, I have to create a local user account for the
user I want to log in with. This is not something I'd like to have to
do. Now, here's a non-working snippet:
passwd: files ldap
shadow: files ldap
group: files ldap
The above causes `klist` to not show Kerberos tickets (and in fact they
aren't retrieved as users cannot access homes). Nothing in the PAM
configuration changed in this test.
I've provided somewhat censored versions of /etc/krb5.conf,
/etc/ldap.conf, /etc/pam.d/system-auth, and /etc/nsswitch.conf. I hope
these will be helpful if anyone would be kind enough to help. If
something else is needed, please do let me know.
John Koelndorfer wrote:
Hello everyone,
I've got a tricky problem that's been gnawing at me for the past few
days or so. First, a little background:
We're running an active directory setup with the usual Windows domain
controllers (they're Windows 2000, if it matters) but users' home
directories are stored on a Linux box running Samba. Our other Linux
servers will need to get at these homes for various reasons. Our setup
is fine with NFSv3, but we were looking to gain security and move up
to NFSv4 with Kerberos authentication. NFSv4 won't allow people to
access their home directories without a valid Kerberos ticket for
their principal. If this could be turned off somehow, that'd be one
way to fix this issue (all_squashing to root doesn't sound
particularly appealing) otherwise I need users to be able to get their
Kerberos ticket on login.
That works fine as long as ldap is not listed in nsswitch.conf. The
problem is we need to use ldap to fetch user info.
So, here's a quick example in case I wasn't clear enough:
I ssh to our server using my domain credentials, kdorf and password.
If I have a local user account on that machine and ldap is *not*
listed in nsswitch.conf, I can login using my domain password and a
valid Kerberos ticket is fetched for me -- I get access to my home.
If I don't have a local account on that machine and ldap *is* listed
in nsswitch.conf, I can login using my domain password but `klist`
shows that I do *not* have a valid Kerberos ticket. Home directory
access is denied.
I need to have valid Kerberos tickets fetched for ldap users.
Alternatively, I would like NFSv4 to not sweat people about Kerberos
tickets to access their homes. Is this possible?
Thanks in advance for your help.
John
[logging]
default = FILE:/var/log/krb5libs.log
kdc = FILE:/var/log/krb5kdc.log
admin_server = FILE:/var/log/kadmind.log
[libdefaults]
ticket_lifetime = 24000
dns_lookup_realm = false
dns_lookup_kdc = false
default_tgs_enctypes = des-cbc-md5, des-cbc-crc
default_tkt_enctypes = des-cbc-md5, des-cbc-crc
default_realm = OUR.REALM.HERE
forwardable = true
[realms]
CEMS.UMN.EDU = {
kdc = OUR.DC.HERE:88
admin_server = OUR.DC.HERE:749
default_domain = our.domain.here
}
[domain_realm]
.cems.umn.edu = OUR.REALM.HERE
cems.umn.edu = OUR.REALM.HERE
[appdefaults]
pam = {
debug = true
ticket_lifetime = 36000
renew_lifetime = 36000
forwardable = true
krb4_convert = false
}
# @(#)$Id: ldap.conf,v 2.35 2004/03/03 21:06:34 lukeh Exp $
#
# This is the configuration file for the LDAP nameservice
# switch library and the LDAP PAM module.
#
# PADL Software
# http://www.padl.com
#
# Your LDAP server. Must be resolvable without using LDAP.
# Multiple hosts may be specified, each separated by a
# space. How long nss_ldap takes to failover depends on
# whether your LDAP client library supports configurable
# network or connect timeouts (see bind_timelimit).
#host 134.84.166.6
# The distinguished name of the search base.
base dc=hidden,dc=for,dc=security
# Another way to specify your LDAP server is to provide an
# uri with the server name. This allows to use
# Unix Domain Sockets to connect to a local LDAP Server.
uri ldaps://our.dc.ip.here.1/ ldaps://our.dc.ip.here.2/
#uri ldaps://127.0.0.1/
#uri ldapi://%2fvar%2frun%2fldapi_sock/
# Note: %2f encodes the '/' used as directory separator
# The LDAP version to use (defaults to 3
# if supported by client library)
#ldap_version 3
# The distinguished name to bind to the server with.
# Optional: default is to bind anonymously.
binddn cn= # removed for security -- this is working
# The credentials to bind with.
# Optional: default is no credential.
bindpw ****************
# The distinguished name to bind to the server with
# if the effective user ID is root. Password is
# stored in /etc/ldap.secret (mode 600)
#rootbinddn cn=cemsadmin,cn=Users,dc=mikedom,dc=cems,dc=umn,dc=edu
# The port.
# Optional: default is 389.
#port 389
#port 636
# The search scope.
scope sub
#scope one
#scope base
# Search timelimit
#timelimit 1
# Bind/connect timelimit
#bind_timelimit 30
# Reconnect policy: hard (default) will retry connecting to
# the software with exponential backoff, soft will fail
# immediately.
#bind_policy hard
# Idle timelimit; client will close connections
# (nss_ldap only) if the server has not been contacted
# for the number of seconds specified below.
#idle_timelimit 3600
# Filter to AND with uid=%s
#pam_filter objectclass=account
# The user ID attribute (defaults to uid)
#pam_login_attribute uid
# Search the root DSE for the password policy (works
# with Netscape Directory Server)
#pam_lookup_policy yes
# Check the 'host' attribute for access control
# Default is no; if set to yes, and user has no
# value for the host attribute, and pam_ldap is
# configured for account management (authorization)
# then the user will not be allowed to login.
#pam_check_host_attr yes
# Check the 'authorizedService' attribute for access
# control
# Default is no; if set to yes, and the user has no
# value for the authorizedService attribute, and
# pam_ldap is configured for account management
# (authorization) then the user will not be allowed
# to login.
pam_check_service_attr yes
# Group to enforce membership of
#pam_groupdn cn=PAM,ou=Groups,dc=padl,dc=com
# Group member attribute
#pam_member_attribute uniquemember
# Specify a minium or maximum UID number allowed
#pam_min_uid 0
#pam_max_uid 0
# Template login attribute, default template user
# (can be overriden by value of former attribute
# in user's entry)
pam_login_attribute userPrincipalName
pam_template_login_attribute uid
pam_template_login nobody
# HEADS UP: the pam_crypt, pam_nds_passwd,
# and pam_ad_passwd options are no
# longer supported.
# Do not hash the password at all; presume
# the directory server will do it, if
# necessary. This is the default.
#pam_password clear
# Hash password locally; required for University of
# Michigan LDAP server, and works with Netscape
# Directory Server if you're using the UNIX-Crypt
# hash mechanism and not using the NT Synchronization
# service.
#pam_password crypt
# Remove old password first, then update in
# cleartext. Necessary for use with Novell
# Directory Services (NDS)
#pam_password nds
# Update Active Directory password, by
# creating Unicode password and updating
# unicodePwd attribute.
#pam_password ad
# Use the OpenLDAP password change
# extended operation to update the password.
#pam_password exop
# Redirect users to a URL or somesuch on password
# changes.
#pam_password_prohibit_message Please visit http://internal to change your
password.
# RFC2307bis naming contexts
# Syntax:
# nss_base_XXX base?scope?filter
# where scope is {base,one,sub}
# and filter is a filter to be &'d with the
# default filter.
# You can omit the suffix eg:
# nss_base_passwd ou=People,
# to append the default base DN but this
# may incur a small performance impact.
nss_base_passwd dc=hidden,dc=for,dc=sec?sub
nss_base_shadow dc=hidden,dc=for,dc=sec?sub
#nss_base_group ou=Group,dc=padl,dc=com?sub
#nss_base_hosts ou=Hosts,dc=padl,dc=com?sub
#nss_base_services ou=Services,dc=padl,dc=com?one
#nss_base_networks ou=Networks,dc=padl,dc=com?one
#nss_base_protocols ou=Protocols,dc=padl,dc=com?one
#nss_base_rpc ou=Rpc,dc=padl,dc=com?one
#nss_base_ethers ou=Ethers,dc=padl,dc=com?one
#nss_base_netmasks ou=Networks,dc=padl,dc=com?ne
#nss_base_bootparams ou=Ethers,dc=padl,dc=com?one
#nss_base_aliases ou=Aliases,dc=padl,dc=com?one
#nss_base_netgroup ou=Netgroup,dc=padl,dc=com?one
# attribute/objectclass mapping
# Syntax:
#nss_map_attribute rfc2307attribute mapped_attribute
#nss_map_objectclass rfc2307objectclass mapped_objectclass
# configure --enable-nds is no longer supported.
# NDS mappings
#nss_map_attribute uniqueMember member
# Services for UNIX 3.5 mappings
nss_map_objectclass posixAccount User
nss_map_objectclass shadowAccount User
nss_map_attribute uid msSFU30Name
nss_map_attribute uidNumber msSFU30UidNumber
nss_map_attribute gidNumber msSFU30GidNumber
nss_map_attribute uniqueMember msSFU30PosixMember
nss_map_attribute userPassword msSFU30Password
nss_map_attribute homeDirectory msSFU30HomeDirectory
nss_map_attribute loginShell msSFU30LoginShell
nss_map_attribute gecos displayname
nss_map_objectclass posixGroup Group
pam_login_attribute msSFU30Name
pam_filter objectclass=User
pam_password ad
# configure --enable-mssfu-schema is no longer supported.
# Services for UNIX 2.0 mappings
#nss_map_objectclass posixAccount User
#nss_map_objectclass shadowAccount user
#nss_map_attribute uid msSFUName
#nss_map_attribute uniqueMember posixMember
#nss_map_attribute userPassword msSFUPassword
#nss_map_attribute homeDirectory msSFUHomeDirectory
#nss_map_attribute shadowLastChange pwdLastSet
#nss_map_objectclass posixGroup Group
#nss_map_attribute cn msSFUName
#pam_login_attribute msSFUName
#pam_filter objectclass=User
#pam_password ad
# RFC 2307 (AD) mappings
#nss_map_objectclass posixAccount user
#nss_map_objectclass shadowAccount user
#nss_map_attribute uid sAMAccountName
#nss_map_attribute homeDirectory unixHomeDirectory
#nss_map_attribute shadowLastChange pwdLastSet
#nss_map_objectclass posixGroup group
#nss_map_attribute uniqueMember member
#pam_login_attribute sAMAccountName
#pam_filter objectclass=User
#pam_password ad
# configure --enable-authpassword is no longer supported
# AuthPassword mappings
#nss_map_attribute userPassword authPassword
# AIX SecureWay mappings
#nss_map_objectclass posixAccount aixAccount
#nss_base_passwd ou=aixaccount,?one
#nss_map_attribute uid userName
#nss_map_attribute gidNumber gid
#nss_map_attribute uidNumber uid
#nss_map_attribute userPassword passwordChar
#nss_map_objectclass posixGroup aixAccessGroup
#nss_base_group ou=aixgroup,?one
#nss_map_attribute cn groupName
#nss_map_attribute uniqueMember member
#pam_login_attribute userName
#pam_filter objectclass=aixAccount
#pam_password clear
# Netscape SDK LDAPS
ssl on
# Netscape SDK SSL options
#sslpath /etc/ssl/certs/cert7.db
# OpenLDAP SSL mechanism
# start_tls mechanism uses the normal LDAP port, LDAPS typically 636
#ssl start_tls
#ssl on
# OpenLDAP SSL options
# Require and verify server certificate (yes/no)
# Default is "no"
tls_checkpeer no
# CA certificates for server certificate verification
# At least one of these are required if tls_checkpeer is "yes"
#tls_cacertfile /etc/ssl/ca.cert
#tls_cacertdir /etc/ssl/certs
# Seed the PRNG if /dev/urandom is not provided
#tls_randfile /var/run/egd-pool
# SSL cipher suite
# See man ciphers for syntax
#tls_ciphers TLSv1
# Client certificate and key
# Use these, if your server requires client authentication.
#tls_cert
#tls_key
# Disable SASL security layers. This is needed for AD.
sasl_secprops maxssf=0 passcred
# Override the default Kerberos ticket cache location.
#krb5_ccname FILE:/etc/.ldapcache
tls_reqcert never
#
# /etc/nsswitch.conf
#
# An example Name Service Switch config file. This file should be
# sorted with the most-used services at the beginning.
#
# The entry '[NOTFOUND=return]' means that the search for an
# entry should stop if the search in the previous entry turned
# up nothing. Note that if the search failed due to some other reason
# (like no NIS server responding) then the search continues with the
# next entry.
#
# Legal entries are:
#
# nis or yp Use NIS (NIS version 2), also called YP
# dns Use DNS (Domain Name Service)
# files Use the local files
# db Use the local database (.db) files
# compat Use NIS on compat mode
# hesiod Use Hesiod for user lookups
# ldap Use LDAP (only if nss_ldap is installed)
# nisplus or nis+ Use NIS+ (NIS version 3), unsupported
# [NOTFOUND=return] Stop searching if not found so far
#
# To use db, put the "db" in front of "files" for entries you want to be
# looked up first in the databases
#
# Example:
#passwd: db files ldap nis
#shadow: db files ldap nis
#group: db files ldap nis
passwd: files ldap
shadow: files ldap
group: files ldap
#hosts: db files ldap nis dns
hosts: files dns
# Example - obey only what ldap tells us...
#services: ldap [NOTFOUND=return] files
#networks: ldap [NOTFOUND=return] files
#protocols: ldap [NOTFOUND=return] files
#rpc: ldap [NOTFOUND=return] files
#ethers: ldap [NOTFOUND=return] files
bootparams: files
ethers: files
netmasks: files
networks: files
protocols: files
rpc: files
services: files
netgroup: files
publickey: files
automount: files
aliases: files
#%PAM-1.0
# This file is auto-generated.
# User changes will be destroyed the next time authconfig is run.
auth required /lib/security/$ISA/pam_env.so
auth sufficient /lib/security/$ISA/pam_krb5.so use_first_pass debug
auth sufficient /lib/security/$ISA/pam_unix.so likeauth nullok
auth required /lib/security/$ISA/pam_deny.so
account required /lib/security/$ISA/pam_unix.so broken_shadow
account sufficient /lib/security/$ISA/pam_krb5.so use_first_pass debug
account sufficient /lib/security/$ISA/pam_succeed_if.so uid < 100 quiet
account required /lib/security/$ISA/pam_permit.so
password requisite /lib/security/$ISA/pam_cracklib.so retry=3
password sufficient /lib/security/$ISA/pam_unix.so nullok use_authtok md5
shadow
password required /lib/security/$ISA/pam_krb5.so use_authtok
minimum_uid=1000 debug
password required /lib/security/$ISA/pam_deny.so
session required /lib/security/$ISA/pam_limits.so
session required /lib/security/$ISA/pam_unix.so
session required /lib/security/$ISA/pam_krb5.so use_first_pass debug
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