Bug 905513

Summary:	Disable libssh2 transport support
Product:	Red Hat Enterprise Linux 7	Reporter:	Jiri Denemark <jdenemar>
Component:	libvirt	Assignee:	Jiri Denemark <jdenemar>
Status:	CLOSED CURRENTRELEASE	QA Contact:	Virtualization Bugs <virt-bugs>
Severity:	medium	Docs Contact:
Priority:	low
Version:	7.0	CC:	acathrow, berrange, cwei, dallan, dyuan, kdudka, mzhan, pkrempa, ydu
Target Milestone:	rc
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	libvirt-1.0.2-1.el7	Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2014-06-13 10:01:08 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description Jiri Denemark 2013-01-29 14:42:38 UTC

Description of problem:

libssh2 transport is implemented upstream but it is not stable/usable enough to be supportable in RHEL 7.0.

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

libvirt-1.0.1-1.el7

How reproducible:

100%

Steps to Reproduce:
1. virsh -c qemu+libssh2://127.0.0.1/system list
  
Actual results:

The command succeeds.


Expected results:

The command should fail with the following message:

error: libssh2 transport support was not enabled: Function not implemented
error: failed to connect to the hypervisor

Additional info:

Comment 1 Daniel Berrangé 2013-01-29 15:00:12 UTC

(In reply to comment #0)
> Description of problem:
> 
> libssh2 transport is implemented upstream but it is not stable/usable enough
> to be supportable in RHEL 7.0.

Please provide links with details of the problems seen, so that when someone looks at this bug in a year's time, we know what motivated us to disable it in the first place.

Comment 2 Jiri Denemark 2013-01-30 10:48:19 UTC

Dave/Peter can you shed some light on that?

Comment 3 Peter Krempa 2013-01-30 11:03:03 UTC

One of the main problems is caused by the incomplete support for host keys stored in the known_hosts file. Libssh2 doesn't support ECDSA keys and corrupts the known hosts file containing those. Commit

commit 225f280744e38fae883bd289ef34bb3f6db71c10
Author: Peter Krempa <pkrempa>
Date:   Tue Aug 21 17:54:26 2012 +0200

    client: Change default location of known_hosts file for libssh2 layer
    
    Unfortunately libssh2 doesn't support all types of host keys that can be
    saved in the known_hosts file. Also it does not report that parsing of
    the file failed. This results into truncated known_hosts files where the
    standard client stores keys also in other formats (eg.
    ecdsa-sha2-nistp256).
    
    This patch changes the default location of the known_hosts file into the
    libvirt private configuration directory, where it will be only written
    by the libssh2 layer itself. This prevents trashing user's known_host
    file.

workarounds that partially by using a separate known_hosts file, but this solution isn't ideal.

Comment 6 Huang Wenlong 2013-02-04 08:24:44 UTC

Verify this bug :
libvirt-1.0.2-1.el7.x86_64

# virsh -c qemu+libssh2://127.0.0.1/system list
error: failed to connect to the hypervisor
error: libssh2 transport support was not enabled: Function not implemented

Comment 8 Ludek Smid 2014-06-13 10:01:08 UTC

This request was resolved in Red Hat Enterprise Linux 7.0.

Contact your manager or support representative in case you have further questions about the request.