ssh connection wait forever

[Rich Ireland]

Matt Johnston wrote:
> On Fri, Mar 18, 2005 at 05:46:56AM -0800, Gavinux wrote:
> 
>>I compiled dropbear for my embedded system
>>(linux-2.4.27, glibc-2.2.5, busybox-1.00). I boot my
>>system from NFS server, then, I use ssh from Redhat
>>7.3 or putty from Win2k to connect to my embedded
>>system, and the ssh client (or putty) wait forever,
>>nothing displayed, until I press some keys on my
>>embedded system's keyboard. and then the cilent
>>prompts username and password.
>>But if I boot my embedded system from local disk,
>>everything is fine.
>>Anything I didn't setup correctly?
>>P.S. The file system and kernel are the same in local
>>disk and NFS server.
> 
> 
> It's probably still the same problem about lack of random
> data (see
> http://lists.ucc.gu.uwa.edu.au/pipermail/dropbear/2005q1/000151.html
> ).
> 
> The solutions are to make sure that there's enough entropy
> and use urandom (if you don't make sure, you'll end up with
> an insecure system), or perhaps look at patches for the
> kernel to get random input from network card timings etc.
> 
> Since you're trusting the NFS link anyway, you could
> probably arrange something with getting entropy from the
> Redhat box - though _only_ if you know that you can trust
> that path.

I concur with Matt's assessment.  These are identical symptoms that I 
encountered on a Cogent CSB337 last month.

If you are using uClibc/buildroot, you can use the patch I recently 
submitted to add a 'low entropy' build option for dropbear.

http://bugs.uclibc.org/view.php?id=138

-- 
Rich Ireland
Firmware Engineer - Perforce Advocate
Idaho Technology, Inc.
http://www.idahotech.com/
mailto:rich.ireland at idahotech.com