[libvirt] [PATCH v2] polkit: Allow password-less access for 'libvirtadm' group

[Daniel P. Berrange]

On Wed, Apr 29, 2015 at 11:35:35AM -0400, Cole Robinson wrote:
> On 04/29/2015 11:28 AM, Daniel P. Berrange wrote:
> > On Wed, Apr 29, 2015 at 11:04:42AM -0400, Cole Robinson wrote:
> >> Many users, who admin their own machines, want to be able to access
> >> system libvirtd via tools like virt-manager without having to enter
> >> a root password. Just google 'virt-manager without password' and
> >> you'll find many hits. I've read at least 5 blog posts over the years
> >> describing slightly different ways of achieving this goal.
> >>
> >> Let's finally add official support for this.
> >>
> >> Install a polkit-1 rules file granting password-less auth for any user
> >> in the new 'libvirtadm' group. Create the group on RPM install
> >>
> >> https://bugzilla.redhat.com/show_bug.cgi?id=957300
> >> ---
> >> v2:
> >> - Name the group libvirtadm (danpb)
> >> - Name the source file libvirt.rules and rename on install (eblake)
> >>
> >>  daemon/Makefile.am   | 13 +++++++++++++
> >>  daemon/libvirt.rules |  9 +++++++++
> >>  libvirt.spec.in      | 15 +++++++++++++--
> >>  3 files changed, 35 insertions(+), 2 deletions(-)
> >>  create mode 100644 daemon/libvirt.rules
> >>
> >> diff --git a/daemon/Makefile.am b/daemon/Makefile.am
> >> index 300b9a5..974feed 100644
> >> --- a/daemon/Makefile.am
> >> +++ b/daemon/Makefile.am
> >> @@ -53,6 +53,7 @@ EXTRA_DIST =						\
> >>  	libvirtd.init.in				\
> >>  	libvirtd.upstart				\
> >>  	libvirtd.policy.in				\
> >> +	libvirt.rules					\
> >>  	libvirtd.sasl					\
> >>  	libvirtd.service.in				\
> >>  	libvirtd.socket.in				\
> >> @@ -233,6 +234,8 @@ policyauth = auth_admin_keep_session
> >>  else ! WITH_POLKIT0
> >>  policydir = $(datadir)/polkit-1/actions
> >>  policyauth = auth_admin_keep
> >> +rulesdir = $(datadir)/polkit-1/rules.d
> >> +rulesfile = libvirt.rules
> >>  endif ! WITH_POLKIT0
> >>  endif WITH_POLKIT
> >>  
> >> @@ -263,9 +266,19 @@ if WITH_POLKIT
> >>  install-data-polkit::
> >>  	$(MKDIR_P) $(DESTDIR)$(policydir)
> >>  	$(INSTALL_DATA) libvirtd.policy $(DESTDIR)$(policydir)/org.libvirt.unix.policy
> >> +if ! WITH_POLKIT0
> >> +	$(MKDIR_P) $(DESTDIR)$(rulesdir)
> >> +	$(INSTALL_DATA) $(srcdir)/$(rulesfile) $(DESTDIR)$(rulesdir)/50-libvirt.rules
> >> +endif ! WITH_POLKIT0
> >> +
> >>  uninstall-data-polkit::
> >>  	rm -f $(DESTDIR)$(policydir)/org.libvirt.unix.policy
> >>  	rmdir $(DESTDIR)$(policydir) || :
> >> +if ! WITH_POLKIT0
> >> +	rm -f $(DESTDIR)$(rulesdir)/50-libvirt.rules
> >> +	rmdir $(DESTDIR)$(rulesdir) || :
> >> +endif ! WITH_POLKIT0
> >> +
> >>  else ! WITH_POLKIT
> >>  install-data-polkit::
> >>  uninstall-data-polkit::
> >> diff --git a/daemon/libvirt.rules b/daemon/libvirt.rules
> >> new file mode 100644
> >> index 0000000..e70c09b
> >> --- /dev/null
> >> +++ b/daemon/libvirt.rules
> >> @@ -0,0 +1,9 @@
> >> +// Allow any user in the 'libvirtadm' group to connect to system libvirtd
> >> +// without entering a password.
> >> +
> >> +polkit.addRule(function(action, subject) {
> >> +    if (action.id == "org.libvirt.unix.manage" &&
> >> +        subject.isInGroup("libvirtadm")) {
> >> +        return polkit.Result.YES;
> >> +    }
> >> +});
> >> diff --git a/libvirt.spec.in b/libvirt.spec.in
> >> index 20af502..10a28a2 100644
> >> --- a/libvirt.spec.in
> >> +++ b/libvirt.spec.in
> >> @@ -1645,9 +1645,9 @@ then
> >>  fi
> >>  
> >>  %if %{with_libvirtd}
> >> +%pre daemon
> >>      %if ! %{with_driver_modules}
> >>          %if %{with_qemu}
> >> -%pre daemon
> >>              %if 0%{?fedora} || 0%{?rhel} >= 6
> >>  # We want soft static allocation of well-known ids, as disk images
> >>  # are commonly shared across NFS mounts by id rather than name; see
> >> @@ -1661,11 +1661,21 @@ if ! getent passwd qemu >/dev/null; then
> >>      useradd -r -g qemu -G kvm -d / -s /sbin/nologin -c "qemu user" qemu
> >>    fi
> >>  fi
> >> -exit 0
> >>              %endif
> >>          %endif
> >>      %endif
> >>  
> >> +    %if %{with_polkit}
> >> +        %if 0%{?fedora} || 0%{?rhel} >= 6
> >> +# 'libvirtadm' group is just to allow password-less polkit access to
> >> +# libvirtd. The uid number is irrelevant, so we use dynamic allocation
> >> +# described at the above link.
> >> +getent group libvirtadm >/dev/null || groupadd -r libvirtadm
> > 
> > Hmm, you know I think we should probably file a bug against the
> > 'setup' RPM in Fedora to request allocation of a group ID value
> > for this, so we can default to using a fixed group ID, as we do
> > for other users/groups we create
> > 
> 
> The recommendations don't seem to suggest that:
> 
> https://fedoraproject.org/wiki/Packaging:UsersAndGroups?rd=Packaging/UsersAndGroups#Allocation_Strategies
> 
> Quote:  Soft static allocation is only appropriate for packages where the UID
> or GID values are shared between computers
> 
> I can't think of a good case when we would need that for libvirtadm...
> cetainly no files need to be owned by it

Ah, ok then. ACK

Regards,
Daniel
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