Re: [exim] Authentication using saslauthd <-> cyrus_sasl

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Author: Christian Schmidt
Date:  
To: exim-users
Subject: Re: [exim] Authentication using saslauthd <-> cyrus_sasl
Hello Andreas,

Andreas Metzler, 22.04.2006 (d.m.y):

> Christian Schmidt <christian@???> wrote:
>
> > I first tried it using:
>
> > sasl_cram_md5:
> > driver = cyrus_sasl
> > public_name = CRAM-MD5
> > server_realm = server.linau.de
> > server_set_id = $2
>
> CRAM-MD5 requires that server knows the clear-text password. If you
> are using PAM this probably not the case and therefore cannot work.


Ah, that wasn't clear to me.

> > sasl_plain:
> > driver = cyrus_sasl
> > public_name = PLAIN
> > server_realm = server.linau.de
> > server_set_id = $2
>
> > This did not work. I always got an error "535 Incorrect authentication
> > data".
>
> <quote>
> Where access to some kind of secret file is required, for example in
> GSSAPI or CRAM-MD5, it is worth noting that the authenticator runs as
> the Exim user, and that the Cyrus SASL library has no way of
> escalating privileges by default. You may also find you need to set
> environment variables, depending on the driver you are using.
> <unquote>
>
> I /guess/ this also applies to reading data from /etc/shadow.


When using saslauthd, there is no need for exim to access "some kind
of secret file", because this is saslauthd's part.
Or did I get that completely wrong?

But what I didn't yet understand is what the differences between the
following two authenticators are:

saslauthd_plain:
driver = plaintext
public_name = PLAIN
server_condition = ${if saslauthd{{$2}{$3}}{True}{False}}

sasl_plain:
driver = cyrus_sasl
public_name = PLAIN
server_realm = server.linau.de
server_set_id = $2

Or in other words: The first authenticator checks the authentication
data by doing a "saslauthd query". And the second one?

My (maybe wrong) imagination has been that the cyrus_sasl driver in
the second authenticator also queries saslauthd.

(I'm not yet familiar with Cyrus IMAPd, but at the moment I think that
Cyrus IMAP authentication works the same way.)


Regards,
Christian

-- 
Joey, los, klon Dich!
        -- Karsten Droste