Guidelines for Updating Kerberos Passwords

The password of Kerberos principal should be periodically changed. To do this, you can either manually specify it by using kadmin.local or automatically randomize principal keys by using the config renew-keytab command of the securityconfig tool.

The syntax for this command is:

config renew-keytab -root <secroot> [-secdir <security dir>]
[-keysalt <enc:salt[,enc:salt,..]>]
[-kadmin-path <kadmin utility path>]
[-instance-name <database instance name>]
[-admin-principal <kerberos admin principal name>]
[-kadmin-keytab <keytab file> ]
[-kadmin-ccache <credential cache file>]

where:

-keysalt

Sets the list of encryption types and salt types to be used for any new keys created. The default value is des3-cbc-sha1:normal,aes128-cts-hmac-sha1-96:normal,arcfour-hmac:normal.
-kadmin-path

Indicates the absolute path of Kerberos kadmin utility. The default value is /usr/kerberos/sbin/kadmin.
-instance-name

Specifies the service principal name. The default value is the fully qualified domain name (FQDN) of the Storage Node where Oracle NoSQL Database is running.
-admin-principal

Specifies the principal used to login to the Kerberos admin interface. This is required while using kadmin keytab or password to connect to the admin interface.
-kadmin-keytab

Specifies the location of a Kerberos keytab file that stores Kerberos admin user principals and encrypted keys. The security configuration tool will use the specified keytab file to login to the Kerberos admin interface.

You need to specify the -admin-principal flag when using keytab to login to the Kerberos admin, otherwise the correct admin principal will not be recognized. This flag cannot be specified in conjunction with the -kadmin-ccache flag.
-kadmin-ccache

Specifies the complete path name to the Kerberos credentials cache file that should contain a service ticket for the kadmin/ADMINHOST. ADMINHOST is the fully-qualified hostname of the admin server or kadmin/admin service.

If not specified, the user is prompted to enter the password for principal while logging to the Kerberos admin interface. This flag cannot be specified in conjunction with the -kadmin-keytab flag.

To manually update the Kerberos principal password instead, you should follow these steps:

Use kadmin.local utility to change the service principal password:

kadmin.local: cpw nosql/myhost
Enter password for principal nosql/myhost@EXAMPLE.COM
Re-enter password for principal nosql/myhost@EXAMPLE.COM

Regenerate the keytab file for Oracle NoSQL Database service principal.
```
kadmin.local: ktadd –norandkey –k new.keytab 
```
Copy the new keytab file for Oracle NoSQL Database service principal to each Storage Node. For example:
```
scp new.keytab kvuser@mystore:KVROOT/security/store.keytab
...
```

Validate the keytab file by comparing the key version number (kvno):

kadmin.local:getprinc nosql/myhost@EXAMPLE.COM
Principal: nosql/myhost@EXAMPLE.COM
Expiration date: [never]
Last password change: Thu Jun 04 03:16:38 UTC 2015
Password expiration date: [none]
Maximum ticket life: 1 day 00:00:00
Maximum renewable life: 0 days 00:00:00
Last modified: Thu Jun 04 03:16:38 UTC 2015 
(root/admin@ORACLE.EXAMPLE.COM)
Last successful authentication: [never]
Last failed authentication: [never]
Failed password attempts: 0
Number of keys: 4
Key: vno 12, aes256-cts-hmac-sha1-96
Key: vno 12, aes128-cts-hmac-sha1-96
Key: vno 12, des3-cbc-sha1
Key: vno 12, arcfour-hmac
MKey: vno 1
Attributes:
Policy: [none]
Kadmin.local: quit
# klist –k new.keytab
KVNO Principal
---- ------------------------
12 nosql/myhost@EXAMPLE.COM
12 nosql/myhost@EXAMPLE.COM
12 nosql/myhost@EXAMPLE.COM
12 nosql/myhost@EXAMPLE.COM

Client side user principals require similar password rotation. Keytab or credential cache used to login to the database should be renewed. If kinit tool is used to create a credential cache, you should run kdestroy to clear cached tickets and re-run kinit to generate a new credential cache.

For example:

# kdestroy –c /tmp/krb5ccache
# kinit –c /tmp/krb5ccache