Changes for page KerberosAndLDAP

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1		-{{toc/}}
2		-
3	3	= Debian =
4	4
5		-The guide I followed was 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 from the upstream Debian Guide.
	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.
6	6
7		-Assumption is that you have installed the LDAP Server package on your NAS and gone through initial configuration steps, so it has a domain, there is a DN you can bind as and so forth. It is also assumed you have a Debian system (12.5 or later, though this guide should work with 11.x and likely 10.x as well) that will become your KDC and KAdmin server.
	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:
8	8
9		-Recommendation is that you create actual ##.ldif## files rather than use here-documents as used in this guide. It is far easier to make adjustments to things if you have a file to edit rather than having to type it all out again or paste it and then have to try and make edits to it without making mistakes.
	7	+{{{
10	10
11		-**The guide is for illustration. Expectation is that you do not follow it verbatim but adapt it to your needs.**
	9	+$ sudo apt install krb5-kdc-ldap krb5-admin-server schema2ldif
12	12
	11	+}}}
13	13
14		-===== Install packages: =====
15	15
16		-(% class="wikigeneratedid" %)
17		-The packages you need are [[krb5-kdc-ldap>>url:https://packages.debian.org/krb5-kdc-ldap]], [[krb5-admin-server>>url:https://packages.debian.org/krb5-admin-server]] for the actual KDC and [[schema2ldif>>url:https://packages.debian.org/schema2ldif]]  plus [[slapd>>https://packages.debian.org/search?keywords=slapd]] for adding the schema and ##slappasswd##. They are to be installed on your designated Debian host.
	14	+Then load the ##kerberos## schema:
18	18
19		-(% style="color:#400" %)
20		-##{{{$ sudo apt install krb5-kdc-ldap krb5-admin-server schema2ldif}}}##
	16	+{{{
21	21
	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
22	22
23		-===== Load ##kerberos LDAP## schema: =====
	20	+adding new entry "cn=kerberos,cn=schema,cn=config"
24	24
25		-Now you need to load the kerberos schema into the LDAP server on the Synology.
	22	+}}}
26	26
27		-(% style="color:#400" %)
28		-##{{{$ zcat /usr/share/doc/krb5-kdc-ldap/kerberos.openldap.ldif.gz | ldapadd -H ldap://nas.example.com/ -D uid=root,cn=users,dc=example,dc=com -W}}}##
29		-##{{{Enter LDAP Password:}}}##
30		-##{{{adding new entry "cn=kerberos,cn=schema,cn=config"}}}##
31		-##{{{$}}}##
32	32
	25	+And add an index on the ##krbPrincipalName## (improves performance and also suppresses some log messages if ##slapd## is configured to log more than default) for the database(s) where you intend to store Kerberos data:
33	33
34		-===== Create Index on krbPrincipalName: =====
	27	+{{{
35	35
36		-Having an index on the ##krbPrincipalName## improves performance and also suppresses some log messages if ##slapd## is configured to log more than default for the database(s) where you intend to store Kerberos data. As this is OpenLDAP on the Synology, it does not use ##mdb## format, it uses ##bdb##. If you install ##slapd## on Debian, it uses ##mdb## format. It is different database format, but the principle is the same.
	29	+# ldapmodify -H ldap:~/~/nas.fqhn <<EOF
37	37
38		-(% style="color:#400" %)
39		-##{{{$ ldapmodify -H ldap://nas.example.com/ -D uid=root,cn=users,dc=example,dc=com -W <<EOF}}}##
40		-##{{{dn: olcDatabase={1}bdb,cn=config}}}##
41		-##{{{add: olcDbIndex}}}##
42		-##{{{olcDbIndex: krbPrincipalName eq,pres,sub}}}##
43		-##{{{EOF}}}##
44		-##{{{Enter LDAP Password:}}}##
45		-##{{{modifying entry "olcDatabase={1}bdb,cn=config"}}}##
46		-##{{{$}}}##
	31	+dn: olcDatabase={1}bdb,cn=config
47	47
	33	+add: olcDbIndex
48	48
49		-===== Create principals kadmin and kdc: =====
	35	+olcDbIndex: krbPrincipalName eq,pres,sub
50	50
51		-Next, you create and configure two entries which will be used by the Kerberos servers to connect to OpenLDAP. As you will not run the Kerberos KDC and Admin Server on the same host as OpenLDAP, these steps are required. In order to keep things nicely separated, everything will be created under a separate ##organizationalUnit##. I diverge from the official Debian guide here as I do not agree with the DN they use. I also had to make changes to the DNs of ##kdc## and ##kadmin## due to ##pwdPolicy## applied by Synology to their LDAP server. The official guide will have you use placeholder passwords and that does not work with the Synology LDAP server. You need to generate them upfront with ##slappasswd##.
	37	+EOF
52	52
53		-(% style="color:#400" %)
54		-##{{{$ ldapadd -H ldap://nas.example.com/ -D uid=root,cn=users,dc=example,dc=com -W <<EOF}}}##
55		-##{{{dn: ou=kerberos,dc=example,dc=com}}}##
56		-##{{{objectClass: organizationalUnit}}}##
57		-##{{{objectClass: top}}}##
58		-##{{{ou: kerberos}}}##
59		-## ##
60		-##{{{dn: uid=kdc,ou=kerberos,dc=example,dc=com}}}##
61		-##{{{uid: kdc}}}##
62		-##{{{objectClass: account}}}##
63		-##{{{objectClass: simpleSecurityObject}}}##
64		-##{{{userPassword: {CRYPT}x}}}##
65		-##{{{description: Kerberos KDC Account}}}##
66		-## ##
67		-##{{{dn: uid=kadmin,ou=kerberos,dc=example,dc=com}}}##
68		-##{{{uid: kadmin}}}##
69		-##{{{objectClass: account}}}##
70		-##{{{objectClass: simpleSecurityObject}}}##
71		-##{{{userPassword: {CRYPT}x}}}##
72		-##{{{description: Kerberos Admin Server Account}}}##
73		-##{{{EOF}}}##
74		-##{{{Enter LDAP Password:}}}##
75		-## ##
76		-##{{{adding new entry "ou=kerberos,dc=example,dc=com"}}}##
77		-## ##
78		-##{{{adding new entry "uid=kdc,ou=kerberos,dc=example,dc=com"}}}##
79		-## ##
80		-##{{{adding new entry "uid=kadmin,ou=kerberos,dc=example,dc=com"}}}##
	39	+modifying entry "olcDatabase={1}bdb,cn=config"
81	81
	41	+}}}
82	82
83		-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, because Synology puts in place password policies. I ended up working around it using a different construct:
84	84
85		-(% style="color:#400" %)
86		-##{{{dn: cn=kadmin,ou=kerberos,ou=Services,dc=example,dc=com}}}##
87		-##{{{sn: kadmin}}}##
88		-##{{{cn: kadmin}}}##
89		-##{{{objectClass: person}}}##
90		-##{{{objectClass: pwdPolicy}}}##
91		-##{{{pwdAttribute: userPassword}}}##
92		-##{{{pwdMinLength: 8}}}##
93		-##{{{pwdCheckQuality: 2}}}##
94		-##{{{pwdPolicySubentry: cn=kadmin,ou=kerberos,ou=Services,dc=example,dc=com}}}##
95		-##{{{userPassword: {SSHA}<hashed password>}}}##
96		-##{{{description: Kerberos Admin Server Account}}}##
	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:
97	97
98		-and that seems to have worked out fine as my KDC is fully functioning.
99	99
100		-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.
	47	+{{{
	48	+# ldapadd -x -D cn=admin,dc=example,dc=com -W <<EOF
	49	+dn: ou=Services,dc=example,dc=com
	50	+objectClass: organizationalUnit
	51	+objectClass: top
	52	+ou: Services
101	101
102		-A note on the above workaround. In order to add a password policy on ##kadmin## and ##kdc## in LDAP, they have to have an attribute that is "physical". And when adding that object class the entries could no longer be a ##uid##. Hence the ##sn## and ##cn## parts. I spent a fair time looking things up as whenever I thought I made progress, something else turned out to be a blocker. When you create the ##{SSHA}## password hash, use ##slappasswd## from the ##slapd## package.
	54	+dn: ou=kerberos,ou=Services,dc=example,dc=com
	55	+objectClass: organizationalUnit
	56	+objectClass: top
	57	+ou: kerberos
	58	+
	59	+dn: uid=kdc,ou=kerberos,ou=Services,dc=example,dc=com
	60	+uid: kdc
	61	+objectClass: account
	62	+objectClass: simpleSecurityObject
	63	+userPassword: {CRYPT}x
	64	+description: Kerberos KDC Account
	65	+
	66	+dn: uid=kadmin,ou=kerberos,ou=Services,dc=example,dc=com
	67	+uid: kadmin
	68	+objectClass: account
	69	+objectClass: simpleSecurityObject
	70	+userPassword: {CRYPT}x
	71	+description: Kerberos Admin Server Account
	72	+EOF
	73	+Enter LDAP Password: SECRET
	74	+
	75	+adding new entry "ou=Services,dc=example,dc=com"
	76	+
	77	+adding new entry "ou=kerberos,ou=Services,dc=example,dc=com"
	78	+
	79	+adding new entry "uid=kdc,ou=kerberos,ou=Services,dc=example,dc=com"
	80	+
	81	+adding new entry "uid=kadmin,ou=kerberos,ou=Services,dc=example,dc=com"}}}
	82	+
	83	+
	84	+