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Bug 634810

Summary:	No authentication after changing VNC password
Product:	Red Hat Enterprise Linux 5	Reporter:	Amos Kong <akong>
Component:	kvm	Assignee:	Gerd Hoffmann <kraxel>
Status:	CLOSED NOTABUG	QA Contact:	Virtualization Bugs <virt-bugs>
Severity:	high	Docs Contact:
Priority:	medium
Version:	5.6	CC:	ailan, mkenneth, virt-maint, ykaul
Target Milestone:	rc
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2010-11-10 16:40:46 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	580948

Description Amos Kong 2010-09-17 04:40:39 UTC

Description of problem:
Boot up a VM and execute monitor command "change vnc password", re-connect vnc port, but there is no authentication.

Version-Release number of selected component (if applicable):
kvm version: kvm-83-193.el5

How reproducible:
100%

Steps to Reproduce:
1. boot up a guest
2. change vnc password
3. re-connect vnc port
  
Actual results:
no password authentication

Expected results:
need password authentication

Additional info:

# qemu-kvm -name 'vm1' -serial unix:'/tmp/serial-20100914-202648-KKQu',server,nowait -drive file='/home/devel/autotest/client/tests/kvm/images/win7-64-virtio.qcow2',index=0,if=virtio,media=disk,cache=none,boot=on,format=qcow2 -net nic,vlan=0,model=virtio,macaddr='02:8F:F3:8D:9e:1e' -net tap,vlan=0,ifname='virtio_0_8000',script='/home/devel/autotest/client/tests/kvm/scripts/qemu-ifup-switch',downscript='no' -m 3000 -smp 2 -drive file='/home/devel/autotest/client/tests/kvm/isos/windows/winutils.iso',media=cdrom,index=1 -cpu qemu64,+x2apic -soundhw ac97 -redir tcp:5000::10023 -vnc :0 -rtc-td-hack -M rhel5.5.0 -usbdevice tablet

Comment 1 Gerd Hoffmann 2010-11-10 16:40:46 UTC

Use '-vnc :0,password' to turn on password authentication.

Comment 2 Amos Kong 2010-11-11 04:46:43 UTC

(In reply to comment #1)
> Use '-vnc :0,password' to turn on password authentication.

Hi Hoffmann,

When I boot up guest with '-vnc :0' (without ',password') in RHEL6, the authentication also works. I'm not sure if it's normal.

Comment 3 Gerd Hoffmann 2010-11-11 09:45:06 UTC

Yes, the upstream qemu behavior has changed at some point that setting a password implicitly turns on password authentication.  RHEL-5 has the old behavior, RHEL-6 the new.

If you want a password-protected vnc session you are better explicitly say so using the password flag even in RHEL-6, otherwise there is a window (between starting qemu and setting the password) where it is possible to connect without authentication.

IMHO there is no good reason to make RHEL-5 match RHEL-6 behaviour, so I'll rather leave it as-is to avoid unpleasant surprises.