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	+##$ sudo apt install krb5-kdc-ldap krb5-admin-server schema2ldif##
10	10
11		-**The guide is for illustration. Expectation is that you do not follow it verbatim but adapt it to your needs.**
	9	+Then load the ##kerberos## schema:
12	12
	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
13	13
14		-===== Install packages: =====
	13	+adding new entry "cn=kerberos,cn=schema,cn=config"
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.
	15	+}}}
18	18
19		-(% style="color:#400" %)
20		-##{{{$ sudo apt install krb5-kdc-ldap krb5-admin-server schema2ldif}}}##
21	21
	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:
22	22
23		-===== Load ##kerberos LDAP## schema: =====
	20	+{{{# 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.
	22	+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		-##{{{$}}}##
	24	+add: olcDbIndex
32	32
	26	+olcDbIndex: krbPrincipalName eq,pres,sub
33	33
34		-===== Create Index on krbPrincipalName: =====
35		-
36		-Having an index on the ##krbPrincipalName## improves performance and also suppresses some log messages if ##slapd## is configured to log more than default for the database(s) where you intend to store Kerberos data. As this is OpenLDAP on the Synology, it does not use ##mdb## format, it uses ##bdb##. If you install ##slapd## on Debian, it uses ##mdb## format. It is different database format, but the principle is the same. Again, as you are modifying config, the DN is ##cn=config##. Interestingly, it is still the main password you set for the Synology LDAP server.
37		-
38		-(% style="color:#400" %)
39		-##{{{$ 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		-##{{{$}}}##
47		-
48		-
49		-===== Create principals kadmin and kdc: =====
50		-
51		-Next, you create and configure two entries which will be used by the Kerberos servers to connect to OpenLDAP. As you will not run the Kerberos KDC and Admin Server on the same host as OpenLDAP, these steps are required. In order to keep things nicely separated, everything will be created under a separate ##organizationalUnit##. I diverge from the official Debian guide here as I do not agree with the DN they use. I also had to make changes to the DNs of ##kdc## and ##kadmin## due to ##pwdPolicy## applied by Synology to their LDAP server. The official guide will have you use placeholder passwords and that does not work with the Synology LDAP server. You need to generate them upfront with ##slappasswd -h {SSHA}##.
52		-
53		-(% style="color:#400" %)
54		-##{{{$ 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		-(% 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}}}##
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:}}}##
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		-
122	122	EOF
123	123
124		-Enter LDAP Password:
125	125	modifying entry "olcDatabase={1}bdb,cn=config"
126	126
127		-$
	32	+}}}
128	128
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.
	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:
131	131
132	132
133		-===== Create your krb5.conf: =====
	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
134	134
135		-Over to adjusting /etc/krb5.conf so that it will point to the right thing later. It should look something like this:
	44	+dn: ou=kerberos,ou=Services,dc=example,dc=com
	45	+objectClass: organizationalUnit
	46	+objectClass: top
	47	+ou: kerberos
136	136
	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
137	137
138		-{{{[libdefaults]
139		- default_realm = EXAMPLE.COM
140		- dns_lookup_realm = false
141		- dns_lookup_kdc = false
142		- ticket_lifetime = 24h
143		- forwardable = true
144		- proxiable = true
145		- rdns = false
	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
146	146
147		-[realms]
148		- EXAMPLE.COM = {
149		- kdc = debian.example.com
150		- admin_server = debian.example.com
151		- default_domain = example.com
152		- }
153		- [domain_realm]
154		- .example.com = EXAMPLE.COM
155		- example.com = EXAMPLE.COM}}}
	65	+adding new entry "ou=Services,dc=example,dc=com"
156	156
157		-Make sure your designated debian server have ports 88, 464 and 749 open, both for TCP and UDP, in its firewall. 88 is for the kdc, 464 and 749 is for kadmin.
	67	+adding new entry "ou=kerberos,ou=Services,dc=example,dc=com"
158	158
159		-Next, we need to write up /etc/krb5kdc/kdc.conf. Something like this should work
	69	+adding new entry "uid=kdc,ou=kerberos,ou=Services,dc=example,dc=com"
160	160
	71	+adding new entry "uid=kadmin,ou=kerberos,ou=Services,dc=example,dc=com"}}}
161	161
162		-[libdefaults]
163	163
164		-[realms]
165		- TRUDHEIM.COM = {
166		- database_module = openldap_ldapconf
167		- max_life = 7d
168		- max_renewable_life = 6d
169		- }
170		-
171		-[dbdefaults]
172		- ldap_kerberos_container_dn = cn=krbContainer,ou=kerberos,dc=trudheim,dc=com
173		-
174		-[dbmodules]
175		- openldap_ldapconf = {
176		- db_library = kldap
177		- disable_last_success = false
178		- disable_lockout = false
179		- ldap_conns_per_server = 5
180		- ldap_servers = ldaps:~/~/ds723.trudheim.com
181		- ldap_kdc_dn = "cn=kdc,ou=kerberos,dc=trudheim,dc=com"
182		- ldap_kadmind_dn = "cn=kadmin,ou=kerberos,dc=trudheim,dc=com"
183		- ldap_service_password_file = /etc/krb5kdc/service.keyfile
184		- }
185		-
186		-
187		-Then you need to create ##/etc/krb5kdc/kadm5.acl and put in it##
188		-
189		-
190		-##*/admin@EXAMPLE.COM *##
191		-
192		-
193		-so that administrator principals can run kadmin. Now we are ready to create the domain. And that we do with
194		-
195		-
196		-#
197		-
198		-kdb5_ldap_util -D uid=root,cn=users,dc=trudheim,dc=com -H ldaps:~/~/ds723.trudheim.com -r TRUDHEIM.COM create -subtrees dc=trudheim,dc=com -maxtktlife '7 Days' -maxrenewlife '6 Days' -s
199		-Password for "uid=root,cn=users,dc=trudheim,dc=com":
200		-Initializing database for realm 'TRUDHEIM.COM'
201		-You will be prompted for the database Master Password.
202		-It is important that you NOT FORGET this password.
203		-Enter KDC database master key:
204		-Re-enter KDC database master key to verify:
205		-
206		-kdb5_ldap_util -D uid=root,cn=users,dc=trudheim,dc=com -H ldaps:~/~/ds723.trudheim.com stashsrvpw -f /etc/krb5kdc/service.keyfile cn=kdc,ou=kerberos,dc=trudheim,dc=com
207		-Password for "uid=root,cn=users,dc=trudheim,dc=com":
208		-Password for "cn=kdc,ou=kerberos,dc=trudheim,dc=com":
209		-Re-enter password for "cn=kdc,ou=kerberos,dc=trudheim,dc=com":
210		-
211		-kdb5_ldap_util -D uid=root,cn=users,dc=trudheim,dc=com -H ldaps:~/~/ds723.trudheim.com stashsrvpw -f /etc/krb5kdc/service.keyfile cn=kadmin,ou=kerberos,dc=trudheim,dc=com
212		-Password for "uid=root,cn=users,dc=trudheim,dc=com":
213		-Password for "cn=kadmin,ou=kerberos,dc=trudheim,dc=com":
214		-Re-enter password for "cn=kadmin,ou=kerberos,dc=trudheim,dc=com":
215		-
216	216