qemu-bridge-helper missing from qemu-kvm or elsewhere

Reported by Justin Cormack on 2013-07-18
This bug affects 6 people
Affects Status Importance Assigned to Milestone
qemu-kvm (Ubuntu)

Bug Description

1. Impact: qemu-bridge helper is not present for users to configure if they
2. Development fix: re-introduce the qemu-bridge-helper
3. Stable fix: same as development fix
4. Test case: ls -l /usr/lib/qemu-bridge-helper
5. Regression potential: none, we just re-add the file.

In Qantal the qemu-bridge-helper was in the qemu-kvm package, see http://packages.ubuntu.com/quantal/amd64/qemu-kvm/filelist

In Raring, it does not appear to be in any package, so it seems to be impossible to create a VM attached to a bridge.

Serge Hallyn (serge-hallyn) wrote :

Note that in quantal that file is shipped without CAP_NET_ADMIN and not suid-root. Therefore it was useless to its intended purpose there.

The point of that file is to allow unprivileged users to create tap devices for their VMs. You can create tap devices yourself for that purpose easily, or use libvirt to do it for you.

Shipping this file and a bridge.conf configuration file isn't out of the question, but would need to be vetted by the security team.

Changed in qemu-kvm (Ubuntu):
importance: Undecided → Wishlist
status: New → Triaged
Calendros (calendros) wrote :

It is great to have the qemu-bridge-helper binary though if someone like me does not want to use libvirt. With a note in a README in /usr/share/doc/ signaling the suid or cap_net_admin was missing, it would be more useful than just removing the binary.

In quantal, adding the right permission was easy. In raring I had to take the binary from quantal distribution (hopefully the binary and linked libraries are compatible).

So please consider to add the binary again in some package since someone could easily install the package and add the permission to qemu-bridge-helper if one wants to do it.

Serge Hallyn (serge-hallyn) wrote :

The debian bug for this is http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=691138 .

I hope to find time to help work out a better helper. In the meantime though, as people were using the helper, I will re-enable it in ubuntu (non-setuid-root). As soon as t opens I will push qemu 1.6 to it, and re-enable it there. Then I'll SRU that change to raring and saucy.

Changed in qemu-kvm (Ubuntu):
importance: Wishlist → Low
Serge Hallyn (serge-hallyn) wrote :

qemu in trusty again ships the helper.

As the priority is low, can someone please chime in asking for raised priority if they want it SRUd in saucy?

Changed in qemu-kvm (Ubuntu):
status: Triaged → Fix Released
Launchpad Janitor (janitor) wrote :

Status changed to 'Confirmed' because the bug affects multiple users.

Changed in qemu-kvm (Ubuntu Raring):
status: New → Confirmed
Changed in qemu-kvm (Ubuntu Saucy):
status: New → Confirmed
Thomas Klute (thomas2-klute) wrote :

I'm trying to build a network simulation using multiple VMs and bridges on my desktop system, and manually configuring TAP interfaces as requirements change is quite cumbersome. I had this working about a year ago using the helper with locally configured capabilities, so I'd very much like to see the qemu-bridge-helper added to saucy. I'm happy to provide a description of the capability configuration for a README if that helps.

Changed in qemu-kvm (Ubuntu):
importance: Low → Medium
Changed in qemu-kvm (Ubuntu Saucy):
importance: Undecided → Medium
no longer affects: qemu-kvm (Ubuntu Raring)
description: updated

Hello Justin, or anyone else affected,

Accepted qemu into saucy-proposed. The package will build now and be available at http://launchpad.net/ubuntu/+source/qemu/1.5.0+dfsg-3ubuntu5.2 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, and change the tag from verification-needed to verification-done. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed. In either case, details of your testing will help us make a better decision.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance!

tags: added: verification-needed
Magosányi Árpád (mag-magwas) wrote :

I can confirm that installing qemu-system-x86 version 1.5.0+dfsg-3ubuntu5.2 from saucy-proposed fixes this bug.

(The vm runs very slowly (maybe it is software emulation), but it must be an unrelated problem.)

tags: added: verification-done
removed: verification-needed
Changed in qemu-kvm (Ubuntu Saucy):
status: Confirmed → Fix Released

The verification of this Stable Release Update has completed successfully and the package has now been released to -updates. Subsequently, the Ubuntu Stable Release Updates Team is being unsubscribed and will not receive messages about this bug report. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regresssions.

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