Support for multiple passwords?

Rick Romero
Wed, 18 Mar 2015 20:10:59 -0000

Quoting Reindl Harald <h.reindl at thelounge.net>:

> Am 18.03.2015 um 20:56 schrieb Conrad Kostecki:
>> Am 2015-03-18 20:46, schrieb Reindl Harald:
>>> Am 18.03.2015 um 20:40 schrieb Conrad Kostecki:
>>>> Hi!
>>>> Currently, the passwords are stored in plaintext for my
dovecot, as I
>>>> am
>>>> still using cram-md5 AND digest-md5.
>>>> I have still to offer that, as I have some deprecated clients,
>>>> therefore, I am unable to hash at least those passwords for
that
>>>> accounts.
>>>>
>>>> I've found on the Wiki:
>>>>> In future it's possible that Dovecot could support
multiple passwords
>>>>> in different schemes for a single user.
>>>>
>>>> Is there any news about this? Are there still any plans to
support
this
>>>> maybe in future?
>>>> For my understanding, that would solve my problem, that I could
>>>> define a
>>>> password in both schemes (cram and digest) and don't have
to use
>>>> plaintext password?
>>>
>>> if you would read http://en.wikipedia.org/wiki/CRAM-MD5 and
understand
>>> how CRAM-MD5 works you would know that you just can't store
cram
>>> because the whole purpose is that it changes all the time
>>
>> Maybe I am totally wrong,
>> but according to the Wiki, if I would be use using CRAM-MD5 without
>> DIGEST-MD5, the password could be stored not in plain text but instead
>> in a cram-md5 scheme?
>> At least, that had worked for me in a test setup. But I will have a
look.
>
> only in a broken and unsecure implementation - or how do you store
> "arbitrary string of random digits, a timestamp"?
>
> http://en.wikipedia.org/wiki/CRAM-MD5
>
> Challenge: The server sends a base64-encoded string to the client.
> Before encoding, it could be any random string, but the standard that
> currently defines CRAM-MD5 says that it is in the format of a Message-ID
> email header value (including angle brackets) and includes an arbitrary
> string of random digits, a timestamp, and the server's fully qualified
> domain name.
>

Too much irrelevant information.  Goal: Don't store cleartext passwords.

Question: Do your clients support PLAIN authentication and SSL?

The authentication method is (mostly) independent of the storage
method.  Only CRAM requires either a clear text password or Dovecot's
CRAM 'cleartext workaround'.

If you use PLAIN, then your passwords can be stored encrypted.  If the
clients support SSL, then you can require SSL/TLS and encrypt the
password (and ALL the content) at the transport layer.

Rick