目标：使 OpenLDAP 服务器通过 GSSAPI 使用 Kerberos V 进行身份验证
设置：在新安装/更新的 Debian Squeeze 上运行的几台虚拟机
主 KDC 服务器
kdc.example.com
运行 OpenLDAP 的 LDAP 服务器
ldap.example.com
问题：
tom@ldap:~$ ldapsearch -b 'dc=example,dc=com'
SASL/GSSAPI authentication started
ldap_sasl_interactive_bind_s: Other (e.g., implementation specific) error (80)
additional info: SASL(-1): generic failure: GSSAPI Error: Unspecified GSS failure. Minor code may provide more information (Key table entry not found)
有人可能会建议添加那个该死的 keytab 条目，但真正的问题是：
ktutil: rkt /etc/ldap/ldap.keytab
ktutil: list
slot KVNO Principal
---- ---- ---------------------------------------------------------------------
1 2 ldap/[email protected]
2 2 ldap/[email protected]
3 2 ldap/[email protected]
4 2 ldap/[email protected]
因此，OpenLDAP 手册建议的条目确实存在。删除并重新创建 ldap.example.com 上的服务主体和密钥表没有帮助，我得到了同样的错误。在我使密钥表文件可供 openldap 读取之前，我得到了“权限被拒绝”错误，而不是主题中的错误。这意味着，正在访问正确的密钥表文件，如 /etc/default/slapd 中设置的那样。
我对 slapd 配置的以下部分有疑问：
root@ldap:~# cat /etc/ldap/slapd.d/cn\=config.ldif | grep -v "^#"
dn: cn=config
objectClass: olcGlobal
cn: config
olcArgsFile: /var/run/slapd/slapd.args
olcLogLevel: 256
olcPidFile: /var/run/slapd/slapd.pid
olcToolThreads: 1
structuralObjectClass: olcGlobal
entryUUID: d6737f5c-d321-1030-9dbe-27d2a7751e11
olcSaslHost: kdc.example.com
olcSaslRealm: EXAMPLE.COM
olcSaslSecProps: noplain,noactive,noanonymous,minssf=56
olcAuthzRegexp: {0}"uid=([^/]*),cn=EXAMPLE.COM,cn=GSSAPI,cn=auth" "uid=$1,ou=People,dc=example,dc=com"
olcAuthzRegexp: {1}"uid=host/([^/]*).example.com,cn=example.com,cn=gssapi,cn=auth" "cn=$1,ou=hosts,dc=example,dc=com"
HOWTO 网址https://help.ubuntu.com/community/OpenLDAPServer#Kerberos_Authentication含糊地提到：
此外，经常需要将授权 Kerberos 客户端的专有名称 (DN) 映射到 DIT 中的现有条目。
我不明白应该在树中的哪个位置定义它，应该使用什么模式，等等。经过几个小时的谷歌搜索，终于得到官方消息：我被困住了！请帮帮我。
检查的其他事项： Kerberos 本身工作得很好（在这个设置下，我可以不用密码 ssh 到任何机器）。这意味着应该没有与 DNS 相关的问题。
ldapsearch -b 'dc=example,dc=com' -x
工作正常。
SASL/GSSAPI 已使用以下工具进行测试
sasl-sample-server -m GSSAPI -s ldap
和
sasl-sample-client -s ldap -n ldap.example.com -u tom
没有错误：
root@ldap:~# sasl-sample-server -m GSSAPI -s ldap
Forcing use of mechanism GSSAPI
Sending list of 1 mechanism(s)
S: R1NTQVBJ
Waiting for client mechanism...
C: 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 'GSSAPI'
Sending response...
S: YIGZBgkqhkiG9xIBAgICAG+BiTCBhqADAgEFoQMCAQ+iejB4oAMCARKicQRvkxggi9pW+yJ1ExbTwLDclqw/VQ98aPq8mt39hkO6PPfcO2cB+t6vJ01xRKBrT9D2qF2XK0SWD4PQNb5UFbH4RM/bKAxDuCfZ1MHKgIWTLu4bK7VGZTbYydcckU2d910jIdvkkHhaRqUEM4cqp/cR
Waiting for client reply...
C: got ''
Sending response...
S: BQQF/wAMAAAAAAAAMBOWqQcACAAlCodrXW66ZObsEd4=
Waiting for client reply...
C: BQQE/wAMAAAAAAAAFUYbXQQACAB0b20VynB4uGH/iIzoRhw=got '?'
Negotiation complete
Username: tom
Realm: (NULL)
SSF: 56
sending encrypted message 'srv message 1'
S: AAAASgUEB/8AAAAAAAAAADATlqrqrBW0NRfPMXMdMz+zqY32YakrHqFps3o/vO6yDeyPSaSqprrhI+t7owk7iOsbrZ/idJRxCBm8Wazx
Waiting for encrypted message...
C: AAAATQUEBv8AAAAAAAAAABVGG17WC1+/kIV9xTMUdq6Y4qYmmTahHVCjidgGchTOOOrBLEwA9IqiTCdRFPVbK1EgJ34P/vxMQpV1v4WZpcztgot ''
recieved decoded message 'client message 1'
root@ldap:~# sasl-sample-client -s ldap -n ldap.example.com -u tom
service=ldap
Waiting for mechanism list from server...
S: R1NTQVBJrecieved 6 byte message
Choosing best mechanism from: GSSAPI
returning OK: tom
Using mechanism GSSAPI
Preparing initial.
Sending initial response...
C: 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
Waiting for server reply...
S: YIGZBgkqhkiG9xIBAgICAG+BiTCBhqADAgEFoQMCAQ+iejB4oAMCARKicQRvkxggi9pW+yJ1ExbTwLDclqw/VQ98aPq8mt39hkO6PPfcO2cB+t6vJ01xRKBrT9D2qF2XK0SWD4PQNb5UFbH4RM/bKAxDuCfZ1MHKgIWTLu4bK7VGZTbYydcckU2d910jIdvkkHhaRqUEM4cqp/cRrecieved 156 byte message
C:
Waiting for server reply...
S: BQQF/wAMAAAAAAAAMBOWqQcACAAlCodrXW66ZObsEd4=recieved 32 byte message
Sending response...
C: BQQE/wAMAAAAAAAAFUYbXQQACAB0b20VynB4uGH/iIzoRhw=
Negotiation complete
Username: tom
SSF: 56
Waiting for encoded message...
S: AAAASgUEB/8AAAAAAAAAADATlqrqrBW0NRfPMXMdMz+zqY32YakrHqFps3o/vO6yDeyPSaSqprrhI+t7owk7iOsbrZ/idJRxCBm8Wazxrecieved 78 byte message
recieved decoded message 'srv message 1'
sending encrypted message 'client message 1'
C: AAAATQUEBv8AAAAAAAAAABVGG17WC1+/kIV9xTMUdq6Y4qYmmTahHVCjidgGchTOOOrBLEwA9IqiTCdRFPVbK1EgJ34P/vxMQpV1v4WZpczt
答案1
Dan White 通过 OpenLDAP 邮件列表给出了答案。
环境
olcSaslHost: ldap.example.com
代替
olcSaslHost: kdc.example.com
解决了这个问题。
不幸的是，olcSaslHost 的 slapd-config(5) 描述有些模糊（至少对我来说）。
Ubuntu 教程页面完全是错误的，内容如下：
“#Kerberos KDC 的 FQDN。olcSaslHost
: kerberos.example.com”
在https://help.ubuntu.com/community/OpenLDAPServer#Kerberos_Authentication