Bug 999914

Summary:	libvirtd is not relabelling the FD from virDomainOpenGraphics
Product:	Red Hat Enterprise Linux 6	Reporter:	Daniel Berrangé <berrange>
Component:	libvirt	Assignee:	Daniel Berrangé <berrange>
Status:	CLOSED NOTABUG	QA Contact:	Virtualization Bugs <virt-bugs>
Severity:	unspecified	Docs Contact:
Priority:	unspecified
Version:	6.6	CC:	acathrow, codong, dyuan, jdenemar, lcui, ydu, zhwang
Target Milestone:	rc
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:
Clones:	999925 (view as bug list)		Environment:
Last Closed:	2013-09-05 17:28:15 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:
Bug Depends On:
Bug Blocks:	999292

Description Daniel Berrangé 2013-08-22 11:18:03 UTC

Description of problem:
When virt-viewer attempts to run virDomainOpenGraphics, strace shows sendmsg() sending the FD, but QEMU never gets it with recvmsg(). THis leads to this error


2013-08-22 10:02:48.263+0000: 11573: debug : virDomainOpenGraphics:21172 : dom=0x1283e10, (VM: name=demo, uuid=62e2a27e-2f92-5545-2c8e-38b2cec76487), idx=0, fd=15, flags=1
(virt-viewer:11573): virt-viewer-DEBUG: Error internal error: unable to execute QEMU command 'getfd': No file descriptor supplied via SCM_RIGHTS


The problem is that the FD libvirt gets is from an unconfined app. It passes this onto QEMU, which will be forbidden to access it. Libvirt needs to relabel it to the svirt image label to allow QEMU access.


Version-Release number of selected component (if applicable):
libvirt-0.10.2-22

How reproducible:
Always

Steps to Reproduce:
1. virt-viewer -c qemu:///session --debug --attach guestname
2.
3.

Actual results:
See the error message
(virt-viewer:11573): virt-viewer-DEBUG: Error internal error: unable to execute QEMU command 'getfd': No file descriptor supplied via SCM_RIGHTS

Expected results:
virDomainOpenGraphics completes without error

Additional info:

Comment 2 Daniel Berrangé 2013-08-22 12:36:24 UTC

commit b6b94374b3bf6b44633ee99a68868141b6cd9ed8
Author: Daniel P. Berrange <berrange>
Date:   Thu Aug 22 12:38:26 2013 +0100

    Set security label on FD for virDomainOpenGraphics

Comment 4 Jiri Denemark 2013-09-05 17:28:15 UTC

As Daniel pointed out in the patch review:

Turns out the RHEL-6 QEMU lacks the monitor command to support this API,
so adding the patch to libvirt is pointless.

We can close this bug then.