> >> Anyway why doesn't write axspawn anything into the
> >> shadow file where the passwords normally are?
No, they aren't there "normally". Passwords are normally in
/etc/passwd. The shadow suite is an optional package intended
to make dictionary attacks against passwords harder.
Automatic account creation and telnet authentication raises some
serious security concerns:
- anyone can login with any login name he wants to
(okay, if you enable auto accounts you've decided to live with this,
after all doing so includes transmitting with a faked call sign which
is considered illegal in most countries)
- with empty/default/easy-to-guess passwords it would be possible for
anyone to change his own uid to that of another user: this does not
involve pirating someone's callsign per-se (as it is only local on
the machine) and -- worse -- allows users of non-ham accounts to
change their uid to that of an AX.25 user -- probably with the
privilege to connect to the packet radio network.
- transmitting plain text passwords over radio defeats any password
encryption completely, be they in /etc/passwd or /etc/shadow.
Adding AX.25 users to /etc/shadow under these circumstances is
plain ridicilous: it gives you a wrong sense of security.
(For similar reasons NIS and the shadow suite don't go along
very well, which is annyoing at first but intended: it forces you
to think about what you are doing.)
> But because I think nearly everyone is using shadow passwords
> nowadays,
Nearly everyone is using PAM nowadays, and you can easily turn of
shadow there. Let me repeat: Shadow login gives you at most only
slight security advantage and using it in an inherently insecure
environment like the AX.25 network is like securing your back door
and leaving the front door wide open.
Talking of PAM: I have a PAMized version of axspawn on
http://ftp.ccac.rwth-aachen.de/pub/jr/
However, I haven't tried to compile that with glibc...
> and there are some people who are using automatic
> user creation there should exist hams with already done solutions,
> so I do not have to code all on my own and reinvent the wheel.
Modify "passwd" to accept the "+" as a "null password" tag (as it
does with "!").
BTW, I've tried to add "shadow" support for axspawn, but I haven't
found a portable, race-condition-free way to do this.
> I only want to use axspawn for user creation. I don't want to give
> shell access as a default, therefore my standard shell will be
> ftponly.
Erm, you shouldn't use real user accounts for this anyway. I know
it is hard to convince ftp clients not to use /etc/passwd...
73,
Joerg Reuter http://poboxes.com/jreuter/
And I make my way to where the warm scent of soil fills the evening air.
Everything is waiting quietly out there.... (Anne Clark)
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