On Tue, Mar 26, 2019 at 12:49:28PM +0100, Andrea Bolognani wrote:
Our current defaults are root:wheel on FreeBSD and macOS, root:root everywhere else.
Looking at what downstream distributions actually do, we can see that these defaults are overriden the vast majority of the time, with a number of variations showing up in the wild:
* qemu:qemu -> Used by CentOS, Fedora, Gentoo, OpenSUSE, RHEL and... As it turns out, our very own spec file :)
* libvirt-qemu:libvirt-qemu -> Used by Debian.
* libvirt-qemu:kvm -> Used by Ubuntu.
* nobody:nobody -> Used by Arch Linux.
Based on the above, we can conclude that qemu:qemu are the preferred credentials to be used when spawning a QEMU process, while our current defaults get very little love.
Changing our defaults aligns with what most downstreams are actually doing, promotes running QEMU under a non-root user - which is a very good idea anyway - and shields random people building libvirt from source from unwittingly running their guests as root.
While I understand the motivation, this impl is problematic because it will guarantee that someone building & installing libvirt from source on Debian, Ubuntu and Arch will have a non-functional QEMU driver as it will try to use a "qemu:qemu" user/group which does not exist on those distros. If we want to change this, we must ensure that we honour the distro specific user/group names you show above, and fallback to root/root for distros we don't know about.
Note that there are a very small number of downstreams that don't override our defaults: Alpine Linux, FreeBSD and macOS. Of those, only Alpine Linux is affected by this change; all three should arguably have been setting --with-qemu-user and --with-qemu-group explicitly regardless of this change.
Signed-off-by: Andrea Bolognani <abologna@redhat.com> ---
Proof that I'm not making any of this up ;)
* Alpine Linux https://github.com/alpinelinux/aports/blob/master/main/libvirt/APKBUILD
* Arch Linux https://aur.archlinux.org/cgit/aur.git/tree/PKGBUILD?h=libvirt-git#n113
* CentOS https://git.centos.org/blob/rpms!libvirt.git/8d86411e5109d791edf49c7f43c08a0...
* Debian https://salsa.debian.org/libvirt-team/libvirt/blob/debian/sid/debian/rules#L...
* Fedora https://src.fedoraproject.org/rpms/libvirt/blob/f29/f/libvirt.spec#_204
* FreeBSD https://github.com/freebsd/freebsd-ports/blob/master/devel/libvirt/Makefile
* Gentoo https://github.com/gentoo/gentoo/blob/master/app-emulation/libvirt/libvirt-5...
* macOS (Homebrew) https://github.com/Homebrew/homebrew-core/blob/master/Formula/libvirt.rb
* OpenSUSE https://build.opensuse.org/package/view_file/openSUSE:Leap:15.0:Update/libvi...
* Ubuntu https://git.launchpad.net/ubuntu/+source/libvirt/tree/debian/rules?h=ubuntu/...
* Upstream https://libvirt.org/git/?p=libvirt.git;a=blob;f=libvirt.spec.in;h=b7a35a0fb1...
m4/virt-driver-qemu.m4 | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/m4/virt-driver-qemu.m4 b/m4/virt-driver-qemu.m4 index cb05c34265..2a1b86e891 100644 --- a/m4/virt-driver-qemu.m4 +++ b/m4/virt-driver-qemu.m4 @@ -44,8 +44,8 @@ AC_DEFUN([LIBVIRT_DRIVER_CHECK_QEMU], [ default_qemu_user=root default_qemu_group=wheel else - default_qemu_user=root - default_qemu_group=root + default_qemu_user=qemu + default_qemu_group=qemu
This would need to be much more clever Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|