Changes for page KerberosAndLDAP

Summary

• Page properties (1 modified, 0 added, 0 removed)

Details

Page properties

Content

...	...	@@ -1,218 +5,65 @@
1		-{{box cssClass="floatinginfobox" title="**Contents**"}}
2		-{{toc/}}
3		-{{/box}}
4		-
5	5	= Debian =
6	6
7		-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.
8	8
9		-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:
10	10
11		-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	+{{{# apt install krb5-kdc-ldap krb5-admin-server schema2ldif}}}
12	12
13		-**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:
14	14
15	15
16		-===== Install packages: =====
	12	+{{{# zcat /usr/share/doc/krb5-kdc-ldap/kerberos.openldap.ldif.gz | ldapadd -Q -Y EXTERNAL -H ldapi:///
	13	+adding new entry "cn=kerberos,cn=schema,cn=config"}}}
17	17
18		-(% class="wikigeneratedid" %)
19		-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	+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:
20	20
21		-(% style="color:#400" %)
22		-##{{{$ sudo apt install krb5-kdc-ldap krb5-admin-server schema2ldif}}}##
23	23
	18	+{{{# ldapmodify -Q -Y EXTERNAL -H ldapi:/// <<EOF
	19	+dn: olcDatabase={1}mdb,cn=config
	20	+add: olcDbIndex
	21	+olcDbIndex: krbPrincipalName eq,pres,sub
	22	+EOF
24	24
25		-===== Load ##kerberos LDAP## schema: =====
	24	+modifying entry "olcDatabase={1}mdb,cn=config"}}}
26	26
27		-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	+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:
28	28
29		-(% style="color:#400" %)
30		-##{{{$ zcat /usr/share/doc/krb5-kdc-ldap/kerberos.openldap.ldif.gz | ldapadd -H ldaps://nas.example.com/ -D cn=config -W}}}##
31		-##{{{Enter LDAP Password:}}}##
32		-##{{{adding new entry "cn=kerberos,cn=schema,cn=config"}}}##
33		-##{{{$}}}##
34	34
	29	+{{{# ldapadd -x -D cn=admin,dc=example,dc=com -W <<EOF
	30	+dn: ou=Services,dc=example,dc=com
	31	+objectClass: organizationalUnit
	32	+objectClass: top
	33	+ou: Services
35	35
36		-===== Create Index on krbPrincipalName: =====
	35	+dn: ou=kerberos,ou=Services,dc=example,dc=com
	36	+objectClass: organizationalUnit
	37	+objectClass: top
	38	+ou: kerberos
37	37
38		-Having an index on the ##krbPrincipalName## improves performance and also suppresses some log messages if ##slapd## is configured to log more than default for the database(s) where you intend to store Kerberos data. As this is OpenLDAP on the Synology, it does not use ##mdb## format, it uses ##bdb##. If you install ##slapd## on Debian, it uses ##mdb## format. It is different database format, but the principle is the same. Again, as you are modifying config, the DN is ##cn=config##. Interestingly, it is still the main password you set for the Synology LDAP server.
	40	+dn: uid=kdc,ou=kerberos,ou=Services,dc=example,dc=com
	41	+uid: kdc
	42	+objectClass: account
	43	+objectClass: simpleSecurityObject
	44	+userPassword: {CRYPT}x
	45	+description: Kerberos KDC Account
39	39
40		-(% style="color:#400" %)
41		-##{{{$ ldapmodify -H ldaps://nas.example.com/ -D cn=config -W <<EOF}}}##
42		-##{{{dn: olcDatabase={1}bdb,cn=config}}}##
43		-##{{{add: olcDbIndex}}}##
44		-##{{{olcDbIndex: krbPrincipalName eq,pres,sub}}}##
45		-##{{{EOF}}}##
46		-##{{{Enter LDAP Password:}}}##
47		-##{{{modifying entry "olcDatabase={1}bdb,cn=config"}}}##
48		-##{{{$}}}##
49		-
50		-
51		-===== Create principals kadmin and kdc: =====
52		-
53		-Next, you create and configure two entries which will be used by the Kerberos servers to connect to OpenLDAP. As you will not run the Kerberos KDC and Admin Server on the same host as OpenLDAP, these steps are required. In order to keep things nicely separated, everything will be created under a separate ##organizationalUnit##. I diverge from the official Debian guide here as I do not agree with the DN they use. I also had to make changes to the DNs of ##kdc## and ##kadmin## due to ##pwdPolicy## applied by Synology to their LDAP server. The official guide will have you use placeholder passwords and that does not work with the Synology LDAP server. You need to generate them upfront with ##slappasswd -h {SSHA}##.
54		-
55		-(% style="color:#400" %)
56		-##{{{$ ldapadd -H ldap://nas.example.com/ -D uid=root,cn=users,dc=example,dc=com -W <<EOF}}}##
57		-##{{{dn: ou=kerberos,dc=example,dc=com}}}##
58		-##{{{objectClass: organizationalUnit}}}##
59		-##{{{objectClass: top}}}##
60		-##{{{ou: kerberos}}}##
61		-
62		-(% style="color:#400" %)
63		-##{{{dn: cn=kdc,ou=kerberos,dc=example,dc=com}}}##
64		-##{{{cn: kdc}}}##
65		-##{{{sn: kdc}}}##
66		-##{{{objectClass: person}}}##
67		-##{{{objectClass: pwdPolicy}}}##
68		-##{{{pwdAttribute: userPassword}}}##
69		-##{{{pwdMinLength: 8}}}##
70		-##{{{pwdCheckQuality: 2}}}##
71		-##{{{pwdPolicySubentry: cn=kdc,ou=kerberos,dc=example,dc=com}}}##
72		-##{{{userPassword: {SSHA}<password-hash>}}}##
73		-##{{{description: Kerberos KDC Account}}}##
74		-
75		-(% style="color:#400" %)
76		-##{{{dn: cn=kadmin,ou=kerberos,dc=example,dc=com}}}##
77		-##{{{cn: kadmin}}}##
78		-##{{{sn: kadmin}}}##
79		-##{{{objectClass: person}}}##
80		-##{{{objectClass: pwdPolicy}}}##
81		-##{{{pwdAttribute: userPassword}}}##
82		-##{{{pwdMinLength: 8}}}##
83		-##{{{pwdCheckQuality: 2}}}##
84		-##{{{pwdPolicySubentry: cn=kadmin,ou=kerberos,dc=example,dc=com}}}##
85		-##{{{userPassword: {SSHA}<password-hash>}}}##
86		-##{{{description: Kerberos KDC Account}}}##
87		-##{{{EOF}}}##
88		-##{{{Enter LDAP Password:}}}##
89		-
90		-(% style="color:#400" %)
91		-##{{{adding new entry "ou=kerberos,dc=example,dc=com"}}}##
92		-
93		-(% style="color:#400" %)
94		-##{{{adding new entry "cn=kdc,ou=kerberos,dc=example,dc=com"}}}##
95		-
96		-(% style="color:#400" %)
97		-##{{{adding new entry "cn=kadmin,ou=kerberos,dc=example,dc=com"}}}##
98		-
99		-
100		-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.
101		-
102		-
103		-===== Grant kdc and kadmin permissions: =====
104		-
105		-This switches back to the ##cn=config## DN as you are changing the permissions.
106		-
107		-$ ldapmodify -H ldaps:~/~/ds723.trudheim.com -W -D cn=config <<EOF
108		-
109		-dn: olcDatabase={1}bdb,cn=config
110		-add: olcAccess
111		-olcAccess: {0}to attrs=krbPrincipalKey
112		- by anonymous auth
113		- by dn.exact="cn=kdc,ou=kerberos,dc=trudheim,dc=com" write
114		- by dn.exact="cn=kadmin,ou=kerberos,dc=trudheim,dc=com" write
115		- by self write
116		- by * none
117		--
118		-add: olcAccess
119		-olcAccess: {1}to dn.subtree="cn=krbContainer,ou=kerberos,dc=example,dc=com"
120		- by dn.exact="cn=kdc,ou=kerberos,dc=trudheim,dc=com" write
121		- by dn.exact="cn=kadmin,ou=kerberos,dc=trudheim,dc=com" write
122		- by * none
123		-
	47	+dn: uid=kadmin,ou=kerberos,ou=Services,dc=example,dc=com
	48	+uid: kadmin
	49	+objectClass: account
	50	+objectClass: simpleSecurityObject
	51	+userPassword: {CRYPT}x
	52	+description: Kerberos Admin Server Account
124	124	EOF
	54	+Enter LDAP Password: SECRET
125	125
126		-Enter LDAP Password:
127		-modifying entry "olcDatabase={1}bdb,cn=config"
	56	+adding new entry "ou=Services,dc=example,dc=com"
128	128
129		-$
	58	+adding new entry "ou=kerberos,ou=Services,dc=example,dc=com"
130	130
	60	+adding new entry "uid=kdc,ou=kerberos,ou=Services,dc=example,dc=com"
131	131
132		-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.
	62	+adding new entry "uid=kadmin,ou=kerberos,ou=Services,dc=example,dc=com"}}}
133	133
134	134
135		-===== Create your krb5.conf: =====
136		-
137		-Over to adjusting /etc/krb5.conf so that it will point to the right thing later. It should look something like this:
138		-
139		-
140		-{{{[libdefaults]
141		- default_realm = EXAMPLE.COM
142		- dns_lookup_realm = false
143		- dns_lookup_kdc = false
144		- ticket_lifetime = 24h
145		- forwardable = true
146		- proxiable = true
147		- rdns = false
148		-
149		-[realms]
150		- EXAMPLE.COM = {
151		- kdc = debian.example.com
152		- admin_server = debian.example.com
153		- default_domain = example.com
154		- }
155		- [domain_realm]
156		- .example.com = EXAMPLE.COM
157		- example.com = EXAMPLE.COM}}}
158		-
159		-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.
160		-
161		-Next, we need to write up /etc/krb5kdc/kdc.conf. Something like this should work
162		-
163		-
164		-[libdefaults]
165		-
166		-[realms]
167		- TRUDHEIM.COM = {
168		- database_module = openldap_ldapconf
169		- max_life = 7d
170		- max_renewable_life = 6d
171		- }
172		-
173		-[dbdefaults]
174		- ldap_kerberos_container_dn = cn=krbContainer,ou=kerberos,dc=trudheim,dc=com
175		-
176		-[dbmodules]
177		- openldap_ldapconf = {
178		- db_library = kldap
179		- disable_last_success = false
180		- disable_lockout = false
181		- ldap_conns_per_server = 5
182		- ldap_servers = ldaps:~/~/ds723.trudheim.com
183		- ldap_kdc_dn = "cn=kdc,ou=kerberos,dc=trudheim,dc=com"
184		- ldap_kadmind_dn = "cn=kadmin,ou=kerberos,dc=trudheim,dc=com"
185		- ldap_service_password_file = /etc/krb5kdc/service.keyfile
186		- }
187		-
188		-
189		-Then you need to create ##/etc/krb5kdc/kadm5.acl and put in it##
190		-
191		-
192		-##*/admin@EXAMPLE.COM *##
193		-
194		-
195		-so that administrator principals can run kadmin. Now we are ready to create the domain. And that we do with
196		-
197		-
198		-#
199		-
200		-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
201		-Password for "uid=root,cn=users,dc=trudheim,dc=com":
202		-Initializing database for realm 'TRUDHEIM.COM'
203		-You will be prompted for the database Master Password.
204		-It is important that you NOT FORGET this password.
205		-Enter KDC database master key:
206		-Re-enter KDC database master key to verify:
207		-
208		-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
209		-Password for "uid=root,cn=users,dc=trudheim,dc=com":
210		-Password for "cn=kdc,ou=kerberos,dc=trudheim,dc=com":
211		-Re-enter password for "cn=kdc,ou=kerberos,dc=trudheim,dc=com":
212		-
213		-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
214		-Password for "uid=root,cn=users,dc=trudheim,dc=com":
215		-Password for "cn=kadmin,ou=kerberos,dc=trudheim,dc=com":
216		-Re-enter password for "cn=kadmin,ou=kerberos,dc=trudheim,dc=com":
217		-
218	218