Public Key Authorization Failure

Rob Landley rob at
Thu Jan 22 02:32:39 WST 2009

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/
> 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/ /tmp/
> B$ cat /tmp/ >> ~/.ssh/authorized_keys
> B$ services sshd restart
> Now attempt a passwordless login to B from A:
> A$ dbclient user at B
> [email protected]'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 

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


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