cpw ignoring password policies

Fri Aug 14 03:38:37 EDT 2020

Hi again Greg,

Please forget my last email. I already found the files that wwwrun should be able to run. I will create a special group for reading the files inside /var/lib/kerberos/krb5kdc/
Now wwwrun acquires correctly the ticket.

Thank you so much.
Kind Regards.

Dario Garcia
Díaz-Miguel
GGCS-SES Unit
GGCS SKMF Infrastructure Division
GMV
C\ de Isaac Newton, 11
28760, Tres Cantos, Madrid
España
+34 918 07 21 00
+34 918 07 21 99
www.gmv.com

-----Mensaje original-----
De: Dario García Díaz-Miguel
Enviado el: viernes, 14 de agosto de 2020 9:12
Para: Greg Hudson <ghudson at mit.edu>; kerberos at mit.edu
Asunto: RE: cpw ignoring password policies

Hi Greg,

Thank you so much for your Support and quick replies, really appreciated.

> That's true.  The kadmin server code deliberately only checks the minimum life if a principal is changing its own password.

Indeed. It makes sense.

> Right, LDAP password history is implemented in release 1.15 but not in 1.12.

I will discuss this point with the project leaders to see if we can upgrade the krb5 version since this is a requirement as well as some supported features in further version such as spake preauth or aes256.

> I guess you could print a kadmin ticket for the user from the KDB and then authenticate with it:
>
> kinit -k -c somefilename -t KDB: -S kadmin/admin username kadmin -c
> somefilename -q "cpw -pw password username"
> kinit -t KDB: support was added in release 1.9, so should be available.

Perfect. This seems to work for me when running the commands as root user. It checks the minimum password life and rejects the change.
But, since the user who ran the script files is wwwrun, I'm getting the following message:

$/usr/lib/mit/bin/kinit -k -c /home/wwwrun/arashimkrbcc -t KDB: -S kadmin/admin arashim
 kinit: No such file or directory while setting up KDB keytab for realm TEST.COM

I've tried with several users and path locations for the cache credentials file but not succedeed. Using sudo before command works flawlessly.
What files or directories this command checks other than the cache credentials created, requiring to grant some permissions to the user who is running it?
According to kinit man, the "KDB:" option looks directly inside the Kerberos Database. So, this should be a permissions issue to access to the Kerberos Database. But honestly, I don't know what files and which should I grant to read to wwwrun to make this work avoiding to hardcode the root password in plain text. I'm not being able to track it on logs either.
Since we built the Kerberos Database on OpenLDAP krbContainer, what file is the one which non-root user should be able to read in order to make this work?

Another option regarding with the idea you sent me could be create a keytab owned by wwwrun to store all users keys and use. However I would prefer to ask the ticket looking directly into the KDB instead of using another keytab for all users. It could be a headache to maintain and totally a bad practice.

Again, thank you so much for your help.
Kind Regards.

Dario Garcia
Díaz-Miguel
GGCS-SES Unit
GGCS SKMF Infrastructure Division
GMV
C\ de Isaac Newton, 11
28760, Tres Cantos, Madrid
España
+34 918 07 21 00
+34 918 07 21 99
www.gmv.com

-----Mensaje original-----
De: Greg Hudson [mailto:ghudson at mit.edu] Enviado el: jueves, 13 de agosto de 2020 17:36
Para: Dario García Díaz-Miguel <dgdiaz at gmv.com>; kerberos at mit.edu
Asunto: Re: cpw ignoring password policies

On 8/13/20 1:51 AM, Dario García Díaz-Miguel wrote:
> I can change all the time the password of the principal with that policy applied despite the minimum password life described.

That's true.  The kadmin server code deliberately only checks the minimum life if a principal is changing its own password.

> Also I'm able to apply old passwords and the history is not being respected, but I'm afraid that's the expected behavior because of the LDAP database module.

Right, LDAP password history is implemented in release 1.15 but not in 1.12.

> I understand that cpw is more like the administration password changing tool and in order to be able to change the password whenever it requires by the system administrator, the minimum password life is not being applied.
> But then, Any ideas about how could we proceed?

I guess you could print a kadmin ticket for the user from the KDB and then authenticate with it:

    kinit -k -c somefilename -t KDB: -S kadmin/admin username
    kadmin -c somefilename -q "cpw -pw password username"

kinit -t KDB: support was added in release 1.9, so should be available.

P Please consider the environment before printing this e-mail.