Bug 1294690 - git ssh issues with ssh-dss
Summary: git ssh issues with ssh-dss
Keywords:
Status: CLOSED EOL
Alias: None
Product: JBoss BRMS Platform 6
Classification: Retired
Component: Business Central
Version: 6.2.0
Hardware: Unspecified
OS: Unspecified
unspecified
unspecified
Target Milestone: DR1
: 6.3.0
Assignee: Alexandre Porcelli
QA Contact: Jiri Locker
URL:
Whiteboard:
: 1311731 (view as bug list)
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2015-12-29 17:29 UTC by Alessandro Lazarotti
Modified: 2020-03-27 20:01 UTC (History)
1 user (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed: 2020-03-27 20:01:20 UTC
Type: Bug
Embargoed:


Attachments (Terms of Use)

Description Alessandro Lazarotti 2015-12-29 17:29:45 UTC
Description of problem:
Some systems are not longer using ssh-dss by default, which results in some issues like:

Client side:
"[lazarotti@mackoy-note git-test]$ git clone ssh://lazarotti@localhost:8001/gss-repo
Cloning into 'gss-repo'...
Unable to negotiate with 127.0.0.1: no matching host key type found. Their offer: ssh-dss
fatal: Could not read from remote repository."

Server side:
14:58:31,856 WARN  [org.apache.sshd.server.session.ServerSession] (sshd-SshServer[847507d]-nio2-thread-2) Exception caught: java.lang.IllegalStateException: Unable to negotiate key exchange for server host key algorithms (client: ecdsa-sha2-nistp256-cert-v01,ecdsa-sha2-nistp384-cert-v01,ecdsa-sha2-nistp521-cert-v01,ssh-ed25519-cert-v01,ssh-rsa-cert-v01,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,ssh-ed25519,ssh-rsa / server: ssh-dss)
	at org.apache.sshd.common.session.AbstractSession.negotiate(AbstractSession.java:1109) [sshd-core-0.12.0.jar:0.12.0]
	at org.apache.sshd.common.session.AbstractSession.doHandleMessage(AbstractSession.java:357) [sshd-core-0.12.0.jar:0.12.0]
	at org.apache.sshd.common.session.AbstractSession.handleMessage(AbstractSession.java:295) [sshd-core-0.12.0.jar:0.12.0]




... while trying to clone a git repo from Business Central.
As mentioned by https://issues.jboss.org/browse/ENTESB-4427 as a longer term solution we should start considering moving away from ssh-dss since according to http://www.openssh.com/legacy.html it's considered insecure, thus deprecated:

> OpenSSH 7.0 and greater similarly disables the ssh-dss (DSA) public key algorithm. It too is weak and we recommend against its use.

Version-Release number of selected component (if applicable):
BRMS 6.2.0

How reproducible:
Always

Steps to Reproduce:
1. try to clone a project repository using standard Fedora 23.
I know it is not supported for BRMS 6.2.0, but it is how RHEL will be work soon.


Additional info:
Also from ENTESB-4427:

An immediate workaround is to alter the configuration of ssh client to accept that security configuration:
ssh -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -o PreferredAuthentications=password -oHostKeyAlgorithms=+ssh-dss  -l admin -p 8101 localhost

or:

Host localhost
    VerifyHostKeyDNS no
    StrictHostKeyChecking no
    HostKeyAlgorithms +ssh-dss
    UserKnownHostsFile /dev/null
can be added to ~/.ssh/config for a global configuration.

Comment 2 Alexandre Porcelli 2016-01-06 21:20:05 UTC
master:
https://github.com/uberfire/uberfire/commit/cec879f64

Comment 3 Alexandre Porcelli 2016-03-02 13:11:42 UTC
*** Bug 1311731 has been marked as a duplicate of this bug. ***

Comment 4 Jiri Locker 2016-04-05 13:23:41 UTC
Verified with BRMS 6.3.0.ER2 on Fedora 23.

Reproduced the described problem, applied global configuration via ~/.ssh/config and successfully cloned after that.

Comment 5 Justin Holmes 2016-05-17 01:21:58 UTC
Team,

What was actually verified here??? I'm testing with 6.3.0 GA and I get still get "no matching host key type found. Their offer: ssh-dss
fatal: Could not read from remote repository."

Alexandre's commit seems to add RSA support, but that does not appear to be in the product.

Comment 7 Alexandre Porcelli 2016-06-13 11:21:40 UTC
https://issues.jboss.org/browse/RHBRMS-243

Comment 8 Alessandro Lazarotti 2016-06-23 22:18:38 UTC
Justin, SFU, see please the Jira above. The Bouncy Castle JCE must be installed in applicaiton server to make it work


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