Public Key Authorization Failure

[Rob Landley]

On Monday 19 January 2009 14:43:13 Kyle Marx wrote:
> Hey,
>    Before anyone flames me, I've read every message in the archive.  That
> said, I am running v0.50 on a TS-7260 ARM9 embedded computer.
>    My problem is that I cannot produce passwordless login from the embedded
> device (A) to my server (B).  I have tried everthing listed.  I first used
> dropbearkey to create private and public keys on the embedded device (A). 
> I appended the pub key to authorized keys on the server (B).
>   My problem is similar to that of 2Q2008 by G*uillaume Dargaud*'s problem.
> Here is a rundown:
>
> Generate keys on the embedded device A:
> A$ dropbearkey -t rsa -f /etc/dropbear/dropbear_rsa_key
> A$ dropbearkey -y -f /etc/dropbear/dropbear_rsa_key | head -2 | tail -1 >
> /etc/dropbear/dropbear_rsa_key.pub
> A$ shutdown -r now
>
> I then append this public key to my authorized keys list on the server, B
> B$ scp user at A:/etc/dropbear/dropbear_rsa_key.pub /tmp/dropbear_rsa_key.pub
> B$ cat /tmp/dropbear_rsa_key.pub >> ~/.ssh/authorized_keys
> B$ services sshd restart
>
> Now attempt a passwordless login to B from A:
> A$ dbclient user at B
> userB@'s password:
>
> It still prompts for a password.  Is this broken?

If all else fails, you can cheese your way around a lot of debugging problems 
by:

A) trying to get it to work on your x86 laptop first.  (Just run it on 
loopback and connect to it from the same machine.)

B) Run it as "dropbear -F -E", and run it under strace.  (Huge amounts of 
debugging output, but you can see _everything_ it's doing.  If it tries to 
open a file, you see the filename.)

C) If all else fails, stick printf() calls into the source code.

> Kyle

Rob