Hash mismatch when SSHing to dropbear server

[Hans-Christian Egtvedt]

Matt Johnston wrote:
> On Thu, Aug 03, 2006 at 04:18:44PM +0200, Hans-Christian Egtvedt wrote:
>> I've compiled dropbear for the avr32 platform, the compilation goes
>> about without any problems, although there is alot of "differ in
>> signedness" warnings.
>>
>> The problem is that it works fine ssh'ing from the avr32 => avr32, but I
>> can't ssh from my workstation (Intel P4 running Ubuntu Dapper).
>>
>> Could the hash mismatch openssh reports on my workstation be related to
>> a big-endian vs. little-endian bug/issue in the dropbear software?
>> The avr32 is big-endian.
> 
>> hash mismatch
>> debug1: ssh_rsa_verify: signature incorrect
>> key_verify failed for server_host_key
> 
>> The same applies if I use a dss key.
> 
>> Any hints or tips to where I should start attacking would be great (-:
> 
> The error suggests that something is going wrong in the
> big-number code (libtommath) - I don't _think_ it's just a
> wrong-endianness issue. A first thing to try might be
> compiling with -O0 or -O2 (rather than -Os as the default?),
> and also trying -fno-strict-aliasing.

I tried most combinations, but they don't effect the result.

> You could also try setting MP_16BIT at the top of
> libtommath/tommath.h - that shouldn't make a difference, but
> it's worth checking.

Didn't do anything good.

> Let me know how it goes, if those don't help I'll have a
> look further.

FWIIW:
: root at 10 / # dbclient workstation -l user
dbclient: connection to user at workstation:22 exited: Bad hostkey signature

: root at 10 / # dbclient localhost

Host 'localhost' is not in the trusted hosts file.
(fingerprint md5 2a:8f:df:71:95:ed:ea:50:4a:fa:16:00:b1:47:c7:22)
Do you want to continue connecting? (y/n)
y
Password:
: root at 10 / #

So the error corrects it self when I ssh localhost, but external targets
is a no-go.

Could this be an alligment error?

-- 
With kind regards,
Med vennlig hilsen,

Hans-Christian Egtvedt
Applications Engineer - AVR Applications Lab
Atmel Norway