RE: SSH key exchange in mid-session

["Mark Riordan" <mriordan@xxxxxxxxxxxx>]

Sorry - I missed this the first time around.

 

libssh does not support key re-exchange right now.  The fact that libssh has
the option of using openssl's cryptographic library does not help, as
openssl does not implement the SSH protocol.

I plan on implementing key re-exchange in libssh, but I'm busy with other
projects right now, so don't hold your breath.

 

Last I looked, it appeared to me that typically a key re-exchange
renegotiates everything from scratch, which I agree sounds excessive.
However, since it happens only every 1 GB (typically), it's not too much
overhead.

 

Mark R

 

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Mark Riordan

Sr Software Developer

T. 608.824.3632 |  <mailto:mriordan@xxxxxxxxxxxx> mriordan@xxxxxxxxxxxx

cid:image001.png@01CAF288.192A5840 
 <http://www.ipswitchft.com/> www.IpswitchFT.com

 

From: Aviv Zilberman [mailto:Aviv.Zilberman@xxxxxxxxxxx] 
Sent: Monday, May 14, 2012 2:26 AM
To: 'libssh@xxxxxxxxxx'
Subject: RE: SSH key exchange in mid-session

 

Any comment ?

Someone ?

 

From: Aviv Zilberman 
Sent: Tuesday, May 01, 2012 3:32 PM
To: libssh@xxxxxxxxxx
Subject: SSH key exchange in mid-session

 

Hello, 

 

I want to start using with libssh in order to achieve SSH communication.

The problem is that the target SSH server (not SFTP server in my case) is
also configuring to drop the session after 1G or 1 hour.

I notice the following limitation of libssh in below link and I have 2
questions :

http://www.libssh.org/archive/libssh/2012-04/0000001.html

1)     As far as I understood from the RFC only the symmetric session key
itself supposed to be exchange - no need to repeat the initialize handshake
include asymmetric keys.

I am right ? is it done automatically ? I think openssh support it so why
libssh not ?

2)     Assuming I would like to support it anyway. Is there a way to do so
using libssh ? if so, what it is ?

 

Thanks in advance,

Aviv      Zilberman.