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Posted to dev@mina.apache.org by "Goldstein Lyor (JIRA)" <ji...@apache.org> on 2015/05/26 08:03:17 UTC
[jira] [Commented] (SSHD-474) Null pointer exception when
connecting with latest Dropbear's dbclient
[ https://issues.apache.org/jira/browse/SSHD-474?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14558714#comment-14558714 ]
Goldstein Lyor commented on SSHD-474:
-------------------------------------
The problem seems to be either an unknown EC curve or a malformed packet that contains an empty _W_ value. From my (incomplete) analysis I tend to favor the latter. Anyway, I added stricter validation checks at earlier stages that should help us diagnose the problem. As far as OpenSSH having no problems with this - it may be the case that it somehow ignores the (bad) KEX packet and re-attempts KEX somehow - we will need to look in our code and see how it handles the problem once we diagnose it better. If you wish to try again and perhaps provide more detailed information regarding the problem, clone and compile the 1.0.0 (snapshot) version (the current _master_ of the GIT repository).
> Null pointer exception when connecting with latest Dropbear's dbclient
> ----------------------------------------------------------------------
>
> Key: SSHD-474
> URL: https://issues.apache.org/jira/browse/SSHD-474
> Project: MINA SSHD
> Issue Type: Bug
> Affects Versions: 0.14.0
> Environment: Apache SSHD 0.14.0 binary distribution on a Redhat 6 system. Oracle Java 1.7.0_25. Dropbear 2015.67.
> Reporter: Andrew Danforth
> Attachments: dbclient.log, sshd.log
>
>
> SSHD throws a null pointer exception when using dbclient from Dropbear 2015.67 to connect. I believe this is due to dbclient attempting to reduce message exchange during key negotiation. If you compile dbclient and comment out #define USE_KEX_FIRST_FOLLOWS from sysoptions.h the session proceeds as expected. FWIW, this version of dbclient has no issues interacting with an OpenSSH daemon.
> I will attach a log of the SSHD output as well as the shell command to start dbclient.
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