Changes for page KerberosAndLDAP
Last modified by Sirius Rayner-Karlsson on 2024/05/09 10:54
From version 18.1
edited by Sirius Rayner-Karlsson
on 2024/05/02 17:09
on 2024/05/02 17:09
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To version 4.1
edited by Sirius Rayner-Karlsson
on 2024/05/01 05:07
on 2024/05/01 05:07
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... ... @@ -2,89 +2,82 @@ 2 2 3 3 The guide I followed was [[https:~~/~~/wiki.debian.org/LDAP/OpenLDAPSetup#Kerberos>>https://wiki.debian.org/LDAP/OpenLDAPSetup#Kerberos]] which while it worked required some minor tweaks. I obtained edit privileges for the Debian Wiki and updated the guide with the fixes that I found. I however have a Synology NAS and that can run an LDAP Server. So this guide differs a little from the upstream Debian Guide. 4 4 5 - 6 6 First, install the packages containing the LDAP-enabled Kerberos servers ([[krb5-kdc-ldap>>url:https://packages.debian.org/krb5-kdc-ldap]] and [[krb5-admin-server>>url:https://packages.debian.org/krb5-admin-server]]) and the [[schema2ldif>>url:https://packages.debian.org/schema2ldif]] tool: 7 7 8 -(% style="color:red" %) 9 -##{{{$ sudo apt install krb5-kdc-ldap krb5-admin-server schema2ldif}}}## 7 +~{~{~{ 10 10 9 +$ sudo apt install krb5-kdc-ldap krb5-admin-server schema2ldif 11 11 11 +}}} 12 + 13 + 12 12 Then load the ##kerberos## schema: 13 13 14 -(% style="color:red" %) 15 -##{{{$ zcat /usr/share/doc/krb5-kdc-ldap/kerberos.openldap.ldif.gz | ldapadd -H ldap://nas.fqdn/ -D uid=root,cn=users,dc=example,dc=com -W}}}## 16 -##{{{Enter LDAP Password:}}}## 17 -##{{{adding new entry "cn=kerberos,cn=schema,cn=config"}}}## 18 -##{{{$}}}## 16 +~{~{~{ 19 19 18 +$ zcat /usr/share/doc/krb5-kdc-ldap/kerberos.openldap.ldif.gz | ldapadd -H ldap:~/~/nas.fqdn/ -D uid=root,cn=users,dc=example,dc=com 20 20 21 - Having an index on the ##krbPrincipalName## improves performance and also suppresses some logmessages if ##slapd## is configuredto log morethandefaultforthe database(s) whereyouintend to store Kerberosdata. As this is OpenLDAP on the Synology,it doesnot use##mdb## format,t uses ##bdb##:20 +adding new entry "cn=kerberos,cn=schema,cn=config" 22 22 23 -(% style="color:red" %) 24 -##{{{$ ldapmodify -H ldap://nas.fqhn/ -D uid=root,cn=users,dc=example,dc=com -W <<EOF}}}## 25 -##{{{dn: olcDatabase={1}bdb,cn=config}}}## 26 -##{{{add: olcDbIndex}}}## 27 -##{{{olcDbIndex: krbPrincipalName eq,pres,sub}}}## 28 -##{{{EOF}}}## 29 -##{{{Enter LDAP Password:}}}## 30 -##{{{modifying entry "olcDatabase={1}bdb,cn=config"}}}## 31 -##{{{$}}}## 22 +}}} 32 32 33 33 34 - Next, youneedto createandconfiguretwoentrieswhich will beused by the Kerberos serverstoconnecttoOpenLDAP. Asyouwill notrun theKerberosKDCandAdminServeronthesame host as OpenLDAP,these stepsarerequired.Inorderto keepthingsnicelyseparated,everythingwill be created underaseparate##organizationalUnit##.25 +And add an index on the ##krbPrincipalName## (improves performance and also suppresses some log messages if ##slapd## is configured to log more than default) for the database(s) where you intend to store Kerberos data: 35 35 36 -(% style="color:red" %) 37 -##{{{$ ldapadd -H ldap://nas.fqhn/ -D uid=root,cn=users,dc=example,dc=com -W <<EOF}}}## 38 -##{{{dn: ou=Services,dc=example,dc=com}}}## 39 -##{{{objectClass: organizationalUnit}}}## 40 -##{{{objectClass: top}}}## 41 -##{{{ou: Services}}}## 42 -## ## 43 -##{{{dn: ou=kerberos,ou=Services,dc=example,dc=com}}}## 44 -##{{{objectClass: organizationalUnit}}}## 45 -##{{{objectClass: top}}}## 46 -##{{{ou: kerberos}}}## 47 -## ## 48 -##{{{dn: uid=kdc,ou=kerberos,ou=Services,dc=example,dc=com}}}## 49 -##{{{uid: kdc}}}## 50 -##{{{objectClass: account}}}## 51 -##{{{objectClass: simpleSecurityObject}}}## 52 -##{{{userPassword: {CRYPT}x}}}## 53 -##{{{description: Kerberos KDC Account}}}## 54 -## ## 55 -##{{{dn: uid=kadmin,ou=kerberos,ou=Services,dc=example,dc=com}}}## 56 -##{{{uid: kadmin}}}## 57 -##{{{objectClass: account}}}## 58 -##{{{objectClass: simpleSecurityObject}}}## 59 -##{{{userPassword: {CRYPT}x}}}## 60 -##{{{description: Kerberos Admin Server Account}}}## 61 -##{{{EOF}}}## 62 -##{{{Enter LDAP Password:}}}## 63 -## ## 64 -##{{{adding new entry "ou=Services,dc=example,dc=com"}}}## 65 -## ## 66 -##{{{adding new entry "ou=kerberos,ou=Services,dc=example,dc=com"}}}## 67 -## ## 68 -##{{{adding new entry "uid=kdc,ou=kerberos,ou=Services,dc=example,dc=com"}}}## 69 -## ## 70 -##{{{adding new entry "uid=kadmin,ou=kerberos,ou=Services,dc=example,dc=com"}}}## 27 +~{~{~{ 71 71 29 +# ldapmodify -H ldap:~/~/nas.fqhn <<EOF 72 72 73 - Now, it was at this pointthat I had a problem, because the LDAP server on the Synology did not likeadding users with placeholder passwords. Iended up working aroundit usinga different construct:31 +dn: olcDatabase={1}bdb,cn=config 74 74 75 -(% style="color:red" %) 76 -##{{{dn: cn=kadmin,ou=kerberos,ou=Services,dc=example,dc=com}}}## 77 -##{{{sn: kadmin}}}## 78 -##{{{cn: kadmin}}}## 79 -##{{{objectClass: person}}}## 80 -##{{{objectClass: pwdPolicy}}}## 81 -##{{{pwdAttribute: userPassword}}}## 82 -##{{{pwdMinLength: 8}}}## 83 -##{{{pwdCheckQuality: 2}}}## 84 -##{{{pwdPolicySubentry: cn=kadmin,ou=kerberos,ou=Services,dc=example,dc=com}}}## 85 -##{{{userPassword: {SSHA}<hashed password>}}}## 86 -##{{{description: Kerberos Admin Server Account}}}## 33 +add: olcDbIndex 87 87 88 - and that seems tohave worked out fine as my KDC is fully functioning. It required modifying the rest of the guide with the fact that it no longer was ##uid=kadmin## and ##uid=kdc##,but rather ##cn=kadmin## and ##cn=kdc##. The most important thing is that it works. As an aside,Iamnot sure it is requiredto havetwo nested Organisation Units, ##Services## and ##kerberos## - so I will likely re-deploy and get rid of the ##Services## OrganisationalUnit altogether. It shortens the DN's used for binds to LDAPand limits therisk for typos. I also find it highly unlikely that deploying this in areal organisation that there would be an existing Organisational Unit called '##kerberos##' while the risk for there being an existing department called '##Services##' is much more likely.35 +olcDbIndex: krbPrincipalName eq,pres,sub 89 89 37 +EOF 38 + 39 +modifying entry "olcDatabase={1}bdb,cn=config" 40 + 41 +}}} 42 + 43 + 44 +Next, you need to create and configure two entries which will be used by the Kerberos servers to connect to OpenLDAP. If you are running Kerberos and OpenLDAP on the same system, these steps are optional, but recommended. In order to keep things nicely separated, everything will be created under a separate ##organizationalUnit##. Note that a simple bind (##-x -D##) is used instead of an ##EXTERNAL## bind since write access to the dc=example,dc=com DIT is necessary: 45 + 46 + 47 +{{{# ldapadd -x -D cn=admin,dc=example,dc=com -W <<EOF 48 +dn: ou=Services,dc=example,dc=com 49 +objectClass: organizationalUnit 50 +objectClass: top 51 +ou: Services 52 + 53 +dn: ou=kerberos,ou=Services,dc=example,dc=com 54 +objectClass: organizationalUnit 55 +objectClass: top 56 +ou: kerberos 57 + 58 +dn: uid=kdc,ou=kerberos,ou=Services,dc=example,dc=com 59 +uid: kdc 60 +objectClass: account 61 +objectClass: simpleSecurityObject 62 +userPassword: {CRYPT}x 63 +description: Kerberos KDC Account 64 + 65 +dn: uid=kadmin,ou=kerberos,ou=Services,dc=example,dc=com 66 +uid: kadmin 67 +objectClass: account 68 +objectClass: simpleSecurityObject 69 +userPassword: {CRYPT}x 70 +description: Kerberos Admin Server Account 71 +EOF 72 +Enter LDAP Password: SECRET 73 + 74 +adding new entry "ou=Services,dc=example,dc=com" 75 + 76 +adding new entry "ou=kerberos,ou=Services,dc=example,dc=com" 77 + 78 +adding new entry "uid=kdc,ou=kerberos,ou=Services,dc=example,dc=com" 79 + 80 +adding new entry "uid=kadmin,ou=kerberos,ou=Services,dc=example,dc=com"}}} 81 + 82 + 90 90