openssh unix dev - Nov 2008 - openssh on interix

Hi openssh developers,

I'm trying to port openssh to Interix. See [1] for more on this.

For Interix sshd needs to be patched to not use setuid()/setgid(), but 
an Interix specific function setuser(). See [2] why it is needed. 
Unfortunately, setuser() needs the clear-text password of the user to 
be fully functional (If you use password-less setuser(), then the 
user doesn't have network access rights, e.g. no access to a network 
home dir).

The problem is now: How to get the clear-text password from
   auth-passwd.c:auth_password()
to
   uidswap.c:permanently_set_uid()
where it would be needed as argument for setuser()?

See [3] for the patch I'm currently using. My first idea would be to 
use the struct passwd pw_passwd field that is passed to 
permanently_set_uid() for storing the clear-text password after 
successful (password-)authentication.

Before looking into details I just want to ask:
Would such use of struct passwd be a security issue?


Many thanks in advance

Martin


[1] http://www.debian-interix.net/
[2]
http://www.suacommunity.com/forum/tm.aspx?m=4663&mpage=1&key=setuser&#7061
[3]
http://www.debian-interix.net/debian-interix/pool/unreleased35/main/o/openssh/openssh_4.7p1-9_4.7p1-9+interix.2.interdiff.gz

Martin Koeppe wrote:
> Hi openssh developers,
> 
> I'm trying to port openssh to Interix. See [1] for more on this.
> 
> For Interix sshd needs to be patched to not use setuid()/setgid(), but 
> an Interix specific function setuser(). See [2] why it is needed. 
> Unfortunately, setuser() needs the clear-text password of the user to 
> be fully functional (If you use password-less setuser(), then the 
> user doesn't have network access rights, e.g. no access to a network 
> home dir).
Sounds like what you are trying to do is run the sshd on a Windows
machine, and get the user's windows password so they can "login"
to Windows?

If the sshd could use the GSSAPI and delegated credentials, it might
be possible to pass the Kerberos ticket into the LSA.  This could give
you single sign on.
I believe with a registry setting, the Kerberos for Windows can do
something like this. You might want to ask on the kerberos at mit.edu list

http://www.vandyke.com/products/vshell/index.html
might be another possibility.
> 
> The problem is now: How to get the clear-text password from
>    auth-passwd.c:auth_password()
> to
>    uidswap.c:permanently_set_uid()
> where it would be needed as argument for setuser()?
> 
> See [3] for the patch I'm currently using. My first idea would be to 
> use the struct passwd pw_passwd field that is passed to 
> permanently_set_uid() for storing the clear-text password after 
> successful (password-)authentication.
> 
> Before looking into details I just want to ask:
> Would such use of struct passwd be a security issue?
> 
> 
> Many thanks in advance
> 
> Martin
> 
> 
> [1] http://www.debian-interix.net/
> [2]
http://www.suacommunity.com/forum/tm.aspx?m=4663&mpage=1&key=setuser&#7061
> [3]
http://www.debian-interix.net/debian-interix/pool/unreleased35/main/o/openssh/openssh_4.7p1-9_4.7p1-9+interix.2.interdiff.gz
> _______________________________________________
> openssh-unix-dev mailing list
> openssh-unix-dev at mindrot.org
> https://lists.mindrot.org/mailman/listinfo/openssh-unix-dev
> 
> 
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  Douglas E. Engert  <DEEngert at anl.gov>
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