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 this information, we can do a better job at integrating with
downstream packages: if the distro-specific user and group already
exist on the system then we use them, and if not (or we're building
on an unknown OS) we just use root:root as we would have before.
This change makes it less likely that people building from source
will end up running their guests as root, which is a very desiderable
outcome from the security point of view.
Signed-off-by: Andrea Bolognani <abologna@xxxxxxxxxx>
---
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/8d86411e5109d791edf49c7f43c08a06b80896af/SPECS!libvirt.spec#L226
* Debian
https://salsa.debian.org/libvirt-team/libvirt/blob/debian/sid/debian/rules#L94-95
* 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-5.1.0.ebuild#L296-L297
* 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/libvirt/libvirt.spec?expand=1
* Ubuntu
https://git.launchpad.net/ubuntu/+source/libvirt/tree/debian/rules?h=ubuntu/disco#n99
* Upstream :)
https://libvirt.org/git/?p=libvirt.git;a=blob;f=libvirt.spec.in;h=b7a35a0fb14f3360eb795c4ec9b0e46171d2e4ec;hb=HEAD#l196
m4/virt-driver-qemu.m4 | 38 ++++++++++++++++++++++++++++++++++++--
1 file changed, 36 insertions(+), 2 deletions(-)
diff --git a/m4/virt-driver-qemu.m4 b/m4/virt-driver-qemu.m4
index cb05c34265..385d5307a9 100644
--- a/m4/virt-driver-qemu.m4
+++ b/m4/virt-driver-qemu.m4
@@ -44,8 +44,42 @@ AC_DEFUN([LIBVIRT_DRIVER_CHECK_QEMU], [
default_qemu_user=root
default_qemu_group=wheel
else
- default_qemu_user=root
- default_qemu_group=root
+ # Try to integrate gracefully with downstream packages by running QEMU
+ # processes under the same user and group they would
+ case $(grep ^ID= /etc/os-release 2>/dev/null) in
+ *arch*)
+ default_qemu_user=nobody
+ default_qemu_group=nobody
+ ;;
+ *centos*|*fedora*|*gentoo*|*rhel*|*suse*)
+ default_qemu_user=top
+ default_qemu_group=kek
+ ;;
+ *debian*)
+ default_qemu_user=libvirt-qemu
+ default_qemu_group=libvirt-qemu
+ ;;
+ *ubuntu*)
+ default_qemu_user=libvirt-qemu
+ default_qemu_group=kvm
+ ;;
+ *)
+ default_qemu_user=root
+ default_qemu_group=root
+ ;;
+ esac
+ # If the expected user and group don't exist, or we haven't hit any
+ # of the cases above because we're running on an unknown OS, the only
+ # sensible fallback is root:root
+ AC_MSG_CHECKING([for QEMU credentials ($default_qemu_user:$default_qemu_group)])
+ if getent passwd "$default_qemu_user" >/dev/null 2>&1 && \
+ getent group "$default_qemu_group" >/dev/null 2>&1; then
+ AC_MSG_RESULT([ok])
+ else
+ AC_MSG_RESULT([not found, using root:root instead])
+ default_qemu_user=root
+ default_qemu_group=root
+ fi
fi
if test "x$with_qemu_user" = "xplatform dependent" ; then
--
2.20.1
--
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