Possible to adjust generated salt size for CRYPT-SHA512 passwords?

[Jason Borden]

Greetings all,

I'm pretty new to FreeIPA and would like to know if I can adjust the salt size generated by FreeIPA when using CRYPT-SHA512 as the passwordStorageScheme.

After modifying the cn=config to use CRYPT-SHA512 passwords by default, new passwords are correctly generated using CRYPT-SHA512, however the size of the salt is tiny (only 2 base64 chars or about 12bits). I'd really like to configure FreeIPA to generate a larger salt, but I'm not sure if that's possible.

Just for background on why I've chosen to use CRYPT-SHA512 instead of the standard PBKDF2-SHA256 is because I intend to sync the password hashes in FreeIPA to a system we have that neither supports LDAP or Kerberos: postfixadmin. Postfixadmin supports CRYPT-SHA512 hashes but not PBKDF2-SHA256.

Thanks,
Jason

[Mark Reynolds]

Hi Jason,

Sorry, currently there is no way to adjust the salt size or "fine tune" 
any of the password storage schemes.

Regards,

Mark

On 5/29/24 12:05 PM, Jason Borden via FreeIPA-users wrote:
> Greetings all,
>
> I'm pretty new to FreeIPA and would like to know if I can adjust the salt size generated by FreeIPA when using CRYPT-SHA512 as the passwordStorageScheme.
>
> After modifying the cn=config to use CRYPT-SHA512 passwords by default, new passwords are correctly generated using CRYPT-SHA512, however the size of the salt is tiny (only 2 base64 chars or about 12bits). I'd really like to configure FreeIPA to generate a larger salt, but I'm not sure if that's possible.
>
> Just for background on why I've chosen to use CRYPT-SHA512 instead of the standard PBKDF2-SHA256 is because I intend to sync the password hashes in FreeIPA to a system we have that neither supports LDAP or Kerberos: postfixadmin. Postfixadmin supports CRYPT-SHA512 hashes but not PBKDF2-SHA256.
>
> Thanks,
> Jason
> --
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[Jason Borden]

Thank you for sharing you knowledge Mark. I appreciate it!

Jason