Changes for page KerberosAndLDAP
Last modified by Sirius Rayner-Karlsson on 2024/05/09 10:54
From version 9.1
edited by Sirius Rayner-Karlsson
on 2024/05/01 17:01
on 2024/05/01 17:01
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To version 18.1
edited by Sirius Rayner-Karlsson
on 2024/05/02 17:09
on 2024/05/02 17:09
Change comment:
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... ... @@ -2,73 +2,89 @@ 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 + 5 5 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: 6 6 7 -##$ sudo apt install krb5-kdc-ldap krb5-admin-server schema2ldif## 8 +(% style="color:red" %) 9 +##{{{$ sudo apt install krb5-kdc-ldap krb5-admin-server schema2ldif}}}## 8 8 11 + 9 9 Then load the ##kerberos## schema: 10 10 11 -{{{$ 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 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 +##{{{$}}}## 12 12 13 -adding new entry "cn=kerberos,cn=schema,cn=config" 14 14 15 - }}}21 +Having an index on the ##krbPrincipalName## improves performance and also suppresses some log messages if ##slapd## is configured to log more than default for the database(s) where you intend to store Kerberos data. As this is OpenLDAP on the Synology, it does not use ##mdb## format, it uses ##bdb##: 16 16 23 +(% style="color:red" %) 24 +##{{{$ 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 +##{{{$}}}## 17 17 18 -And add an index on the ##krbPrincipalName## (improves performance and also suppresses some log messages if ##slapd## is configured to log more than default) for the database(s) where you intend to store Kerberos data: 19 19 20 - {{{#ldapmodify-Hldap:~/~/nas.fqhn<<EOF34 +Next, you need to create and configure two entries which will be used by the Kerberos servers to connect to OpenLDAP. As you will not run the Kerberos KDC and Admin Server on the same host as OpenLDAP, these steps are required. In order to keep things nicely separated, everything will be created under a separate ##organizationalUnit##. 21 21 22 -dn: olcDatabase={1}bdb,cn=config 36 +(% style="color:red" %) 37 +##{{{$ 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"}}}## 23 23 24 -add: olcDbIndex 25 25 26 -o lcDbIndex:krbPrincipalName eq,pres,sub73 +Now, it was at this point that I had a problem, because the LDAP server on the Synology did not like adding users with placeholder passwords. I ended up working around it using a different construct: 27 27 28 -EOF 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}}}## 29 29 30 -modifying entr y"olcDatabase={1}bdb,cn=config"88 +and that seems to have 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, I am not sure it is required to have two nested Organisation Units, ##Services## and ##kerberos## - so I will likely re-deploy and get rid of the ##Services## Organisational Unit altogether. It shortens the DN's used for binds to LDAP and limits the risk for typos. I also find it highly unlikely that deploying this in a real 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. 31 31 32 -}}} 33 - 34 - 35 -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: 36 - 37 - 38 -{{{# ldapadd -x -D cn=admin,dc=example,dc=com -W <<EOF 39 -dn: ou=Services,dc=example,dc=com 40 -objectClass: organizationalUnit 41 -objectClass: top 42 -ou: Services 43 - 44 -dn: ou=kerberos,ou=Services,dc=example,dc=com 45 -objectClass: organizationalUnit 46 -objectClass: top 47 -ou: kerberos 48 - 49 -dn: uid=kdc,ou=kerberos,ou=Services,dc=example,dc=com 50 -uid: kdc 51 -objectClass: account 52 -objectClass: simpleSecurityObject 53 -userPassword: {CRYPT}x 54 -description: Kerberos KDC Account 55 - 56 -dn: uid=kadmin,ou=kerberos,ou=Services,dc=example,dc=com 57 -uid: kadmin 58 -objectClass: account 59 -objectClass: simpleSecurityObject 60 -userPassword: {CRYPT}x 61 -description: Kerberos Admin Server Account 62 -EOF 63 -Enter LDAP Password: SECRET 64 - 65 -adding new entry "ou=Services,dc=example,dc=com" 66 - 67 -adding new entry "ou=kerberos,ou=Services,dc=example,dc=com" 68 - 69 -adding new entry "uid=kdc,ou=kerberos,ou=Services,dc=example,dc=com" 70 - 71 -adding new entry "uid=kadmin,ou=kerberos,ou=Services,dc=example,dc=com"}}} 72 - 73 - 74 74