--- /dev/null
+
+
+# central usermanagement
+
+...using ldap and kerberos
+
+
+# motivation
+
+warum:
+
+* skaliert
+* sicherheit
+* komfort (single sign on)
+warum nicht:
+
+* fehlerquelle komplexitaet
+* gefahr single point of failure / break in
+-> infrastruktur!
+
+
+# theorie
+
+recommended reading:
+
+* [[http://www.openinput.com/auth-howto/index.html|http://www.openinput.com/auth-howto/index.html]]
+* [[http://www.pdc.kth.se/heimdal/|http://www.pdc.kth.se/heimdal/]]
+* [[http://www.openldap.org/doc/admin23/|http://www.openldap.org/doc/admin23/]]
+architektur:
+
+* trusted third party, der KDC. hat gemeinsames secret mit allen hosts/services/usern. "principals". generiert auf anfrage ticket mit zeit, ip, und welcher user zu welchem service.
+design decisions:
+
+* keine passwoerter im ldap, alles via kerberos, rueckwaertskompatibilitaet via pam_krb, nicht sasl oder pam_ldap.
+* kerberos datenbank im ldap, keine seperate replikation noetig (nur mit heimdal).
+* eigene ldap range fuer uid/groupid, root und systemuser bleiben lokal falls das netzwerk spinnt.
+
+# required software
+
+zutaten am server:
+
+* heimdal kerberos (ldap), alternativen: mit, shishi
+* openldap, alternativ: mysql, postgresql
+* wohlgepflegtes dns und reverse-dns
+* schwer empfohlen: replikation und redundanz
+
+[[!format txt """
+sudo aptitude install slapd heimdal-kdc
+"""]]
+zutaten am host:
+
+* libnss-ldap
+* pam-krb5
+* sasl mit gssapi provider
+* richtige zeit, zb. openntpd (kann aber nicht stratum faken fuer windows)
+* kerberized client/serversoftware (zb. openssh, apache2)
+
+[[!format txt """
+sudo aptitude install libnss-ldap libpam-krb5 libsasl2-gssapi-mit heimdal-clients
+"""]]
+
+# vorbereitung: domain name service
+
+config im dns (da gibts uebrigens auch welche mit ldap/sql backend ;):
+
+aka "srv records rock! - for kerberos but not for ldap :("
+
+config file /etc/krb5.conf auf allen hosts ident!
+
+was ist ein "canonical hostname"?
+
+zonefile mm-karton.com (snippet):
+[[!format txt """
+$ORIGIN mm-karton.com.
+kerberos A 10.128.0.24
+kerberos-1 A 10.128.0.25
+ldap CNAME srv-vie-26.vie.mm-karton.com.
+ldap-1 CNAME srv-vie-27.vie.mm-karton.com.
+
+_kerberos TXT "MM-KARTON.COM"
+_kerberos-master._tcp SRV 10 1 88 kerberos
+_kerberos-master._udp SRV 10 1 88 kerberos
+_kpasswd._udp SRV 10 1 464 kerberos
+_kerberos-adm._tcp SRV 10 1 749 kerberos
+_kerberos._tcp SRV 10 1 88 kerberos
+_kerberos._udp SRV 10 1 88 kerberos
+_kerberos._tcp SRV 20 1 88 kerberos-1
+_kerberos._udp SRV 20 1 88 kerberos-1
+
+_ldap._tcp SRV 10 1 88 ldap
+_ldap._tcp SRV 20 1 88 ldap-1
+"""]]
+zonefile mm-karton.net (snippet), afaik heimdal specific:
+[[!format txt """
+_kerberos TXT "MM-KARTON.COM"
+"""]]
+
+# config am server
+
+/etc/ldap/slapd.conf
+
+
+[[!format txt """
+# This is the main slapd configuration file. See slapd.conf(5) for more
+# info on the configuration options.
+
+#######################################################################
+# Global Directives:
+
+include /etc/ldap/schema/core.schema
+include /etc/ldap/schema/cosine.schema
+include /etc/ldap/schema/nis.schema
+include /etc/ldap/schema/inetorgperson.schema
+
+include /etc/ldap/schema/hdb.schema
+
+
+TLSCACertificateFile /etc/ldap/ca_crt.pem
+TLSCertificateFile /etc/ldap/ldap.mm-karton.com_crt.pem
+TLSCertificateKeyFile /etc/ldap/ldap.mm-karton.com_key.pem
+TLSCipherSuite HIGH:MEDIUM:+SSLv2
+
+
+pidfile /var/run/slapd/slapd.pid
+argsfile /var/run/slapd/slapd.args
+
+loglevel 0
+
+modulepath /usr/lib/ldap
+moduleload back_bdb
+moduleload syncprov
+
+# The maximum number of entries that is returned for a search operation
+sizelimit 500
+
+
+
+
+#######################################################################
+# Specific Backend Directives for bdb:
+
+backend bdb
+checkpoint 512 30
+
+
+
+#######################################################################
+# main database
+database bdb
+suffix "dc=mm-karton,dc=com"
+rootdn "cn=ldapmaster@mm-karton.com,dc=mm-karton,dc=com"
+
+directory "/var/lib/ldap"
+dbconfig set_cachesize 0 33554432 0
+lastmod on
+
+
+index objectClass eq
+index cn,uid,displayName eq,sub,pres
+index krb5PrincipalName eq
+index associatedDomain pres,eq,sub
+index entryUUID,default,entryCSN eq
+
+
+# needed for syncrepl
+overlay syncprov
+syncprov-checkpoint 100 10
+syncprov-sessionlog 100
+
+limits dn.exact="cn=ldap/srv-vie-27.vie.mm-karton.com@mm-karton.com,ou=kdc,dc=mm-karton,dc=com" time.soft=unlimited time.hard=unlimited size.soft=unlimited size.hard=unlimited
+
+
+
+
+
+
+#######################################################################
+# sasl config
+
+sasl-secprops minssf=0
+security simple_bind=64
+
+sasl-regexp
+ uid=(.+),cn=.+,cn=auth
+ ldap:///dc=mm-karton,dc=com??sub?(|(uid=$1)(krb5PrincipalName=$1@MM-KARTON.COM))
+sasl-regexp "=0" "cn=ldapmaster@mm-karton.com,dc=mm-karton,dc=com"
+
+
+
+
+#######################################################################
+# access control
+
+# needed for certain auth stuff
+access to dn.base="" by * read
+access to dn.base="cn=Subschema" by * read
+
+access to attrs=krb5PrincipalName
+ by dn="cn=unki@mm-karton.com,dc=mm-karton,dc=com" write
+ by dn="cn=lefant@mm-karton.com,dc=mm-karton,dc=com" write
+ by dn="cn=ldap/srv-vie-27.vie.mm-karton.com@mm-karton.com,ou=kdc,dc=mm-karton,dc=com" read
+ by anonymous auth
+
+access to attrs=userPassword
+ by dn="cn=unki@mm-karton.com,dc=mm-karton,dc=com" write
+ by dn="cn=lefant@mm-karton.com,dc=mm-karton,dc=com" write
+ by dn="cn=ldap/srv-vie-27.vie.mm-karton.com@mm-karton.com,ou=kdc,dc=mm-karton,dc=com" read
+ by anonymous auth
+
+
+
+# Kerberos attributes only accessible to root/ldapmaster and the superadmins
+access to attrs=krb5KeyVersionNumber,krb5PrincipalRealm,krb5EncryptionType,krb5KDCFlags,krb5Key,krb5MaxLife,krb5MaxRenew,krb5PasswordEnd,krb5ValidEnd,krb5ValidStart,krb5RealmName
+ by dn="cn=unki@mm-karton.com,dc=mm-karton,dc=com" write
+ by dn="cn=lefant@mm-karton.com,dc=mm-karton,dc=com" write
+ by dn="cn=ldap/srv-vie-27.vie.mm-karton.com@mm-karton.com,ou=kdc,dc=mm-karton,dc=com" read
+ by * none
+
+
+
+# user info readable for nssproxy user
+access to dn.subtree="ou=users,dc=mm-karton,dc=com"
+ by dn="cn=unki@mm-karton.com,dc=mm-karton,dc=com" write
+ by dn="cn=lefant@mm-karton.com,dc=mm-karton,dc=com" write
+ by dn="cn=ldap/srv-vie-27.vie.mm-karton.com@mm-karton.com,ou=kdc,dc=mm-karton,dc=com" read
+ by dn="uid=nssproxy,dc=mm-karton,dc=com" read
+access to dn.subtree="ou=groups,dc=mm-karton,dc=com"
+ by dn="cn=unki@mm-karton.com,dc=mm-karton,dc=com" write
+ by dn="cn=lefant@mm-karton.com,dc=mm-karton,dc=com" write
+ by dn="cn=ldap/srv-vie-27.vie.mm-karton.com@mm-karton.com,ou=kdc,dc=mm-karton,dc=com" read
+ by dn="uid=nssproxy,dc=mm-karton,dc=com" read
+access to attrs=uid,uidNumber,gidNumber,gecos,homeDirectory,loginShell,memberUid
+ by dn="cn=unki@mm-karton.com,dc=mm-karton,dc=com" write
+ by dn="cn=lefant@mm-karton.com,dc=mm-karton,dc=com" write
+ by dn="cn=ldap/srv-vie-27.vie.mm-karton.com@mm-karton.com,ou=kdc,dc=mm-karton,dc=com" read
+ by dn="uid=nssproxy,dc=mm-karton,dc=com" read
+
+
+
+# all the rest
+access to dn.subtree="dc=mm-karton,dc=com"
+ by dn="cn=unki@mm-karton.com,dc=mm-karton,dc=com" write
+ by dn="cn=lefant@mm-karton.com,dc=mm-karton,dc=com" write
+ by dn="cn=ldap/srv-vie-27.vie.mm-karton.com@mm-karton.com,ou=kdc,dc=mm-karton,dc=com" read
+"""]]
+/etc/default/slapd
+[[!format txt """
+# Default location of the slapd.conf file
+SLAPD_CONF=
+
+# System account to run the slapd server under. If empty the server
+# will run as root.
+SLAPD_USER="openldap"
+
+# System group to run the slapd server under. If empty the server will
+# run in the primary group of its user.
+SLAPD_GROUP="openldap"
+
+# Path to the pid file of the slapd server. If not set the init.d script
+# will try to figure it out from $SLAPD_CONF (/etc/ldap/slapd.conf)
+SLAPD_PIDFILE=
+
+# Configure if the slurpd daemon should be started. Possible values:
+# - yes: Always start slurpd
+# - no: Never start slurpd
+# - auto: Start slurpd if a replica option is found in slapd.conf (default)
+SLURPD_START=auto
+
+# slapd normally serves ldap only on all TCP-ports 389. slapd can also
+# service requests on TCP-port 636 (ldaps) and requests via unix
+# sockets.
+# Example usage:
+SLAPD_SERVICES="ldap://10.128.4.36/ ldapi:///"
+
+# Additional options to pass to slapd and slurpd
+SLAPD_OPTIONS=""
+SLURPD_OPTIONS=""
+
+export KRB5_KTNAME="FILE:/etc/ldap/ldap.keytab"
+
+[ -L /var/run/ldapi ] || ln -s /var/run/slapd/ldapi /var/run/ldapi
+"""]]
+/etc/heimdal-kdc/kadmin.acl
+[[!format txt """
+lefant/admin@MM-KARTON.COM all
+"""]]
+/etc/heimdal-kdc/kdc.conf
+[[!format txt """
+[kdc]
+ database = {
+ realm = MM-KARTON.COM
+ dbname = ldap:dc=mm-karton,dc=com
+ mkey_file = /var/lib/heimdal-kdc/m-key
+ acl_file = /etc/heimdal-kdc/kadmind.acl
+ }
+ addresses = 10.128.0.24
+"""]]
+
+[[!format txt """
+$ sudo kadmin -l
+init MY.REALM
+add lefant/admin
+"""]]
+
+# config am host
+
+/etc/libnss-ldap.conf
+[[!format txt """
+BASE dc=mm-karton, dc=com
+URI ldap://ldap.mm-karton.com/,ldap://ldap-1.mm-karton.com/
+
+ldap_version 3
+ssl start_tls
+tls_cacertfile /etc/ssl/certs/mmagca_crt.pem
+
+binddn uid=nssproxy,dc=mm-karton,dc=com
+bindpw XXXXXXXX
+
+scope sub
+pam_filter objectClass=posixAccount
+nss_base_passwd ou=users,dc=mm-karton,dc=com
+nss_base_group ou=groups,dc=mm-karton,dc=com
+
+# Search timelimit
+timelimit 10
+
+# Bind/connect timelimit
+bind_timelimit 2
+
+pam_min_uid 10000
+pam_max_uid 11000
+
+nss_reconnect_tries 1
+nss_reconnect_sleeptime 1
+nss_reconnect_maxsleeptime 2
+nss_reconnect_maxconntries 3
+nss_initgroups_ignoreusers arpwatch,asterisk,backup,bin,bind,clamav,cricket,daemon,Debian-exim,debianmirror,dovecot,fetchmail,ftp,games,gnats,identd,irc,list,lp,mail,man,messagebus,mysql,nagios,news,nobody,ntp,ntpd,nut,openvpn,pdns,proftpd,proxy,puppet,root,smmsp,smmta,smsd,snmp,snort,sshd,statd,sync,sys,uucp,www-data,zope
+"""]]
+/etc/nsswitch.conf
+[[!format txt """
+passwd: files ldap
+group: files ldap
+shadow: files
+
+hosts: files dns
+networks: files
+
+protocols: db files
+services: db files
+ethers: db files
+rpc: db files
+
+netgroup: nis
+"""]]
+/etc/krb5.conf
+[[!format txt """
+[libdefaults]
+ default_realm = MM-KARTON.COM
+ dns_lookup_realm = yes
+
+[logging]
+ default = SYSLOG:NOTICE:DAEMON
+ kdc = FILE:/var/log/kdc.log
+ kadmind = FILE:/var/log/kadmind.log
+
+[appdefaults]
+ pam = {
+ ticket_lifetime = 10h
+ renew_lifetime = 10h
+ forwardable = true
+ proxiable = false
+ retain_after_close = false
+ minimum_uid = 0
+ debug = false
+ }
+
+[domain_realm]
+ srv-pof-30.pof.mmk.mmdom.net = MM-KARTON.COM
+
+[realms]
+ MMK.MMDOM.NET = {
+ kdc = DC-VIE-50
+ kpasswd_server = DC-VIE-50
+ auth_to_local_names = {
+ lefant = invaliduser
+ unki = invaliduser
+ }
+ }
+ MM-KARTON.COM = {
+ admin_server = kerberos.mm-karton.com
+ auth_to_local = RULE:[1:$1@$0](^.*@MMK.MMDOM.NET$)s/@MMK.MMDOM.NET//
+ auth_to_local = DEFAULT
+ }
+"""]]
+/etc/pam.d/common-account
+[[!format txt """
+account required pam_access.so
+account sufficient pam_krb5.so forwardable realm=MMK.MMDOM.NET minimum_uid=20000
+account sufficient pam_krb5.so forwardable realm=MM-KARTON.COM minimum_uid=20000
+account required pam_unix.so
+"""]]
+/etc/pam.d/common-auth
+[[!format txt """
+auth optional pam_group.so
+auth sufficient pam_krb5.so forwardable realm=MMK.MMDOM.NET minimum_uid=20000 try_first_pass
+auth sufficient pam_krb5.so forwardable realm=MM-KARTON.COM minimum_uid=20000 try_first_pass
+auth required pam_unix.so try_first_pass
+"""]]
+/etc/pam.d/common-session
+[[!format txt """
+session required pam_mkhomedir.so umask=0022 skel=/etc/mmskel
+session sufficient pam_krb5.so forwardable realm=MMK.MMDOM.NET minimum_uid=20000
+session sufficient pam_krb5.so forwardable realm=MM-KARTON.COM minimum_uid=20000
+session required pam_unix.so
+"""]]
+restrict logins to certain users:
+
+/etc/security/access.conf
+[[!format txt """
+# first, to avoid delays when network is still unavailable
++:ALL:LOCAL
++:root:ALL
+
+# remote users and groups
++:bofh:ALL
+
+# deny everything else
+-:ALL:ALL
+"""]]
+/etc/adduser.conf (snippet)
+[[!format txt """
+# FIRST_[GU]ID to LAST_[GU]ID inclusive is the range of UIDs of dynamically
+# allocated user accounts/groups.
+FIRST_UID=1000
+LAST_UID=19999
+"""]]
+ldap client config (administration):
+
+/etc/ldap/ldap.conf
+[[!format txt """
+BASE dc=mm-karton, dc=com
+URI ldap://ldap.mm-karton.com/
+ssl start_tls
+tls_cacert /etc/ssl/certs/ca_crt.pem
+"""]]
+ldapwhoami, ldapsearch
+
+sudo, nopasswd, weil solches haben wir ja nicht...
+
+/etc/sudoers
+[[!format txt """
+lefant ALL=(ALL) NOPASSWD:ALL
+"""]]
+
+# single sign on fuer applikationen (gssapi support, das grosse fragezeichen)
+
+/etc/ssh/sshd_config (snippet)
+[[!format txt """
+GSSAPIAuthentication yes
+GSSAPIKeyExchange yes
+"""]]
+/etc/ssh/ssh_config (snippet)
+[[!format txt """
+host *
+ GSSAPIAuthentication yes
+ GSSAPIDelegateCredentials yes
+ GSSAPITrustDns yes
+"""]]
+firefox: out-of-the-box!
+
+apache: (apt-get install libapache2-mod-auth-kerb) config snippet
+[[!format txt """
+ <Location />
+ AuthType Kerberos
+ AuthName "MM Login (use windows login *without* mm\ prefix)"
+ KrbServiceName HTTP
+ Krb5Keytab /etc/apache2/keytab
+ KrbAuthRealms MMK.MMDOM.NET MM-KARTON.COM
+ AuthGroupFile /etc/wwwusers
+ Require group NocUsers
+ Order deny,allow
+ Deny from all
+ Allow from noc.mm-karton.com
+ Satisfy any
+ </Location>
+"""]]
+
+# misc stuff
+
+* tcpdump
+* strace
+* $HOME/.k5login
\ No newline at end of file
projects / debienna.git / blobdiff