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	+'''
	8	+$ sudo apt install krb5-kdc-ldap krb5-admin-server schema2ldif
	9	+'''
10	10
11		-**The guide is for illustration. Expectation is that you do not follow it verbatim but adapt it to your needs.**
	11	+Then load the ##kerberos## schema:
12	12
	13	+'''
	14	+$ 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
	15	+Password:
13	13
14		-===== Install packages: =====
	17	+adding new entry "cn=kerberos,cn=schema,cn=config"
	18	+'''
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.
18	18
19		-(% style="color:#400" %)
20		-##{{{$ sudo apt install krb5-kdc-ldap krb5-admin-server schema2ldif}}}##
21	21
	22	+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:
22	22
23		-===== Load ##kerberos LDAP## schema: =====
	24	+{{{# ldapmodify -H ldap:~/~/nas.fqhn <<EOF
24	24
25		-Now you need to load the kerberos schema into the LDAP server on the Synology. And here you need to use the ##cn=config## DN.
	26	+dn: olcDatabase={1}bdb,cn=config
26	26
27		-(% style="color:#400" %)
28		-##{{{$ zcat /usr/share/doc/krb5-kdc-ldap/kerberos.openldap.ldif.gz | ldapadd -H ldaps://nas.example.com/ -D cn=config -W}}}##
29		-##{{{Enter LDAP Password:}}}##
30		-##{{{adding new entry "cn=kerberos,cn=schema,cn=config"}}}##
31		-##{{{$}}}##
	28	+add: olcDbIndex
32	32
	30	+olcDbIndex: krbPrincipalName eq,pres,sub
33	33
34		-===== Create Index on krbPrincipalName: =====
	32	+EOF
35	35
36		-Having an index on the ##krbPrincipalName## improves performance and also suppresses some log messages if ##slapd## is configured to log more than default for the database(s) where you intend to store Kerberos data. As this is OpenLDAP on the Synology, it does not use ##mdb## format, it uses ##bdb##. If you install ##slapd## on Debian, it uses ##mdb## format. It is different database format, but the principle is the same. Again, as you are modifying config, the DN is ##cn=config##. Interestingly, it is still the main password you set for the Synology LDAP server.
	34	+modifying entry "olcDatabase={1}bdb,cn=config"
37	37
38		-(% style="color:#400" %)
39		-##{{{$ ldapmodify -H ldaps://nas.example.com/ -D cn=config -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		-##{{{$}}}##
	36	+}}}
47	47
48	48
49		-===== Create principals kadmin and kdc: =====
	39	+Next, you need to create and configure two entries which will be used by the Kerberos servers to connect to OpenLDAP. If you are running Kerberos and OpenLDAP on the same system, these steps are optional, but recommended. In order to keep things nicely separated, everything will be created under a separate ##organizationalUnit##. Note that a simple bind (##-x -D##) is used instead of an ##EXTERNAL## bind since write access to the dc=example,dc=com DIT is necessary:
50	50
51		-Next, you create and configure two entries which will be used by the Kerberos servers to connect to OpenLDAP. As you will not run the Kerberos KDC and Admin Server on the same host as OpenLDAP, these steps are required. In order to keep things nicely separated, everything will be created under a separate ##organizationalUnit##. I diverge from the official Debian guide here as I do not agree with the DN they use. I also had to make changes to the DNs of ##kdc## and ##kadmin## due to ##pwdPolicy## applied by Synology to their LDAP server. The official guide will have you use placeholder passwords and that does not work with the Synology LDAP server. You need to generate them upfront with ##slappasswd -h {SSHA}##.
52	52
53		-(% style="color:#400" %)
54		-##{{{$ 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}}}##
	42	+{{{# ldapadd -x -D cn=admin,dc=example,dc=com -W <<EOF
	43	+dn: ou=Services,dc=example,dc=com
	44	+objectClass: organizationalUnit
	45	+objectClass: top
	46	+ou: Services
59	59
60		-(% style="color:#400" %)
61		-##{{{dn: cn=kdc,ou=kerberos,dc=example,dc=com}}}##
62		-##{{{cn: kdc}}}##
63		-##{{{sn: kdc}}}##
64		-##{{{objectClass: person}}}##
65		-##{{{objectClass: pwdPolicy}}}##
66		-##{{{pwdAttribute: userPassword}}}##
67		-##{{{pwdMinLength: 8}}}##
68		-##{{{pwdCheckQuality: 2}}}##
69		-##{{{pwdPolicySubentry: cn=kdc,ou=kerberos,dc=example,dc=com}}}##
70		-##{{{userPassword: {SSHA}<password-hash>}}}##
71		-##{{{description: Kerberos KDC Account}}}##
	48	+dn: ou=kerberos,ou=Services,dc=example,dc=com
	49	+objectClass: organizationalUnit
	50	+objectClass: top
	51	+ou: kerberos
72	72
73		-(% style="color:#400" %)
74		-##{{{dn: cn=kadmin,ou=kerberos,dc=example,dc=com}}}##
75		-##{{{cn: kadmin}}}##
76		-##{{{sn: kadmin}}}##
77		-##{{{objectClass: person}}}##
78		-##{{{objectClass: pwdPolicy}}}##
79		-##{{{pwdAttribute: userPassword}}}##
80		-##{{{pwdMinLength: 8}}}##
81		-##{{{pwdCheckQuality: 2}}}##
82		-##{{{pwdPolicySubentry: cn=kadmin,ou=kerberos,dc=example,dc=com}}}##
83		-##{{{userPassword: {SSHA}<password-hash>}}}##
84		-##{{{description: Kerberos KDC Account}}}##
85		-##{{{EOF}}}##
86		-##{{{Enter LDAP Password:}}}##
	53	+dn: uid=kdc,ou=kerberos,ou=Services,dc=example,dc=com
	54	+uid: kdc
	55	+objectClass: account
	56	+objectClass: simpleSecurityObject
	57	+userPassword: {CRYPT}x
	58	+description: Kerberos KDC Account
87	87
88		-(% style="color:#400" %)
89		-##{{{adding new entry "ou=kerberos,dc=example,dc=com"}}}##
90		-
91		-(% style="color:#400" %)
92		-##{{{adding new entry "cn=kdc,ou=kerberos,dc=example,dc=com"}}}##
93		-
94		-(% style="color:#400" %)
95		-##{{{adding new entry "cn=kadmin,ou=kerberos,dc=example,dc=com"}}}##
96		-
97		-
98		-Synology LDAP server did not like adding users with placeholder passwords, because Synology puts in place password policies. Hence changing this to a ##cn## instead of a ##uid##. It seems to have worked out fine as my KDC is fully functioning.
99		-
100		-
101		-===== Grant kdc and kadmin permissions: =====
102		-
103		-This switches back to the ##cn=config## DN as you are changing the permissions.
104		-
105		-$ ldapmodify -H ldaps:~/~/ds723.trudheim.com -W -D cn=config <<EOF
106		-
107		-dn: olcDatabase={1}bdb,cn=config
108		-add: olcAccess
109		-olcAccess: {0}to attrs=krbPrincipalKey
110		- by anonymous auth
111		- by dn.exact="cn=kdc,ou=kerberos,dc=trudheim,dc=com" write
112		- by dn.exact="cn=kadmin,ou=kerberos,dc=trudheim,dc=com" write
113		- by self write
114		- by * none
115		--
116		-add: olcAccess
117		-olcAccess: {1}to dn.subtree="cn=krbContainer,ou=kerberos,dc=example,dc=com"
118		- by dn.exact="cn=kdc,ou=kerberos,dc=trudheim,dc=com" write
119		- by dn.exact="cn=kadmin,ou=kerberos,dc=trudheim,dc=com" write
120		- by * none
121		-
	60	+dn: uid=kadmin,ou=kerberos,ou=Services,dc=example,dc=com
	61	+uid: kadmin
	62	+objectClass: account
	63	+objectClass: simpleSecurityObject
	64	+userPassword: {CRYPT}x
	65	+description: Kerberos Admin Server Account
122	122	EOF
	67	+Enter LDAP Password: SECRET
123	123
124		-Enter LDAP Password:
125		-modifying entry "olcDatabase={1}bdb,cn=config"
	69	+adding new entry "ou=Services,dc=example,dc=com"
126	126
127		-$
	71	+adding new entry "ou=kerberos,ou=Services,dc=example,dc=com"
128	128
	73	+adding new entry "uid=kdc,ou=kerberos,ou=Services,dc=example,dc=com"
129	129
130		-Note that we now reference our kdc and kadmin accounts and we grant them permission to the krbContainer which will house all our kerberos principals. Give both of them write access, because we do want to have the ability to track last login and lock accounts if there are login failures. We like security.
	75	+adding new entry "uid=kadmin,ou=kerberos,ou=Services,dc=example,dc=com"}}}
131	131
	77	+
132	132