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Network Security Secure-Shell
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RE: Why am I sending the publickey?

Subject: RE: Why am I sending the publickey?
Date: Tue, 21 Mar 2006 17:12:22 -0500
No, I didn't need to, as removing the malformed ssh-rsa line in the
remote system's /root/.ssh/authorized_keys file solved the problem.

Thanks, again, for your help and suggestions.

-Kevin

-----Original Message-----
From: Gian G. Spicuzza [mailto:gianspi@gsent.org] 
Sent: Tuesday, March 21, 2006 4:04 PM
To: Zembower, Kevin; secureshell@securityfocus.com
Subject: Re: Why am I sending the publickey?

Did you increase the max retrys in sshd_config?
The default is:

MaxAuthTries 6 


Zembower, Kevin wrote:

Gian and Raz, thank you for your suggestions.

Gian, I'm able to logon with PreferredAuthentications=password.
However,
after I send my public key, I still can't make a connection:

[root@xxx2 ~]# cat ~/.ssh/id_rsa.pub | ssh -o
PreferredAuthentications=password xxx.xxx.xxx 'umask 022; cat
 

~/.ssh/authorized_keys'
     

root@xxx.xxx.xxx password: 
[root@xxx2 ~]# ssh xxx.xxx.xxx
Connection closed by xx.xxx.xxx.xxx
[root@xxx2 ~]#

Raz, I think you're on to something, suspecting that there's a problem.
I get this message in /var/log/auth.log when the connection fails:

Mar 21 11:42:20 main sshd[16735]: fatal: buffer_get: trying to get more
bytes 129 than in buffer 36
main:/var/log#

After searching on Google, I found this solution involving improper
line
endings in ~/.ssh/authorized_keys:
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=64972. Their
solution was to erase the key in question, which I had done previously.
However, I noticed that the key preceding the one in question seemed to
be malformed. It was much longer than the other ssh-rsa keys, and
contained spaces, which the other ones did not. Removing this key
solved
the problem. I can now log on using either password or public key.

Thank you all very much for your help and suggestions.

-Kevin Zembower

----Original Message-----
From: Roland Turner (Security Focus)
[mailto:raz.frphevglsbphf.pbz@raz.cx] 
Sent: Monday, March 20, 2006 11:15 AM
To: secureshell@securityfocus.com
Subject: Re: Why am I sending the publickey?

On Mon, 2006-03-20 at 10:12 -0500, Zembower, Kevin wrote:

 

debug1: Authentications that can continue:
publickey,password,keyboard-interactive
debug1: Next authentication method: publickey
debug1: Trying private key: /root/.ssh/identity
debug1: Offering public key: /root/.ssh/id_rsa
Connection closed by xx.xx.xx.xx
[root@xxx .ssh]#

I don't understand why it's trying the publickey method.

On the remote host, I've removed the lines in /root/.ssh/authorized
   

keys
 

for the host I'm coming from, and restarted sshd,
   


Your client is offering a key because your server is indicating a
willingness to accept one (this is controlled by sshd_config, not
authorized_keys).

There's some brokenness here though; it's not clear why the connection
is closing immediately after the public key is offered. It should
refuse
it, then move on to the other authorisation methods. A sudden closure
suggests that your server process is aborting (e.g. a segmentation
violation). How confident are you that your server build is reasonable?

- Raz



 


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