Long delay during login

[Avner Flesch]

Hi,

I used dropbear that was ported to tomsfastmath library(instead of
tommath).
I reduced the login delay on my machine (powerpc 8xx 50MHz) to 5
seconds!

I would like to reduce the delay more. Is anyone has any idea?

Thanks

Avner

-----Original Message-----
From: Avner Flesch <avnerf at web-silicon.com>
To: Rob Landley <rob at landley.net>
Cc: Gary <gmart at coinet.com>, dropbear at ucc.asn.au
Subject: Re: Long delay during login
Date: Tue, 11 Oct 2011 18:05:01 +0200

Hi,

I have also the same issue with dropbear version 0.53.1 on powerpc 50MHz
32bits the login took more then 30 seconds.
After I updated the libtomath library to version 0.42 and libtomcrypt
version to 1.17
I reduced the delay to 13 seconds.

But it still not enough - after a research I found that the delay is in
the routine "mp_exptmod_fast" from libtommath, there is a for(;;) loop
that take a while.
Is anyone know how can I overcome this issue?

Thanks

Avner

-----Original Message-----
From: Rob Landley <rob at landley.net>
To: Gary <gmart at coinet.com>
Cc: dropbear at ucc.asn.au
Subject: Re: Long delay during login
Date: Sat, 01 Oct 2011 14:00:28 -0500


On 09/28/2011 01:31 PM, Gary wrote:
> Matt Johnston <matt <at> ucc.asn.au> writes:
> 
> On Mon, Jun 13, 2005 at 10:21:53AM +0100, Simon Rowe wrote:
>> We're seeing a long delay when logging in using dropbear on to our embedded 
>> system (60MHz PowerPC). Looking at the debug from the client end it appears 
>> that the issue is the Diffie-Hellman key negotiation within dropbear
>>
>> debug1: expecting SSH2_MSG_KEXDH_REPLY
>>
>> [delay of about 8 seconds]
>>
>> Is there anything we can change to reduce this delay?
> 
> 
> Same problem here.  My bet is that it's blocking on the random 
> device.  For me ssh'ng to a busy machine is fast, ssh'ng to an
> idle machine almost always has a BIG delay.

Switch from /dev/random to /dev/urandom perhaps?

Rob




-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.ucc.gu.uwa.edu.au/pipermail/dropbear/attachments/20111023/3af68003/attachment.htm