[libvirt] [PATCH 0/5] qemu: invoke qemu-bridge-helper from libvirtd

Paolo Bonzini pbonzini at redhat.com
Mon Mar 25 14:25:27 UTC 2013


The <interface type='bridge'> is working mostly because of a bad design
decision in Linux.  Ideally, QEMU would run with an empty capability
bounding set and would not be able to do any privileged operation
(not even by running a helper program).  This is not the case because
dropping capabilities from the bounding set requires a capability of its
own, CAP_SETPCAP; thus QEMU does *not* run with an empty bounding set if
invoked via qemu:///session.

This series lets libvirtd invoke the privileged helper program on its own,
which is a cleaner design that would work even if the above Linux bug
was not there.  Also, this adds a <target dev='tap0'/> element to the
XML of an active domain using <interface type='bridge'>.

libvirt now needs to know the path to the helper (patch
3), and must not set permitted/effective capabilities on children when
running unprivileged (patches 1/2).  Apart from this, the recvfd and
virCommand APIs make the task almost trivial.

Paolo Bonzini (5):
  util: simplify virSetUIDGIDWithCaps
  util: allow using virCommandAllowCap with setuid helpers
  qemu_conf: add new configuration key bridge_helper
  virnetdevtap: add virNetDevTapGetName
  qemu: launch bridge helper from libvirtd

 src/libvirt_private.syms           |   1 +
 src/qemu/libvirtd_qemu.aug         |   1 +
 src/qemu/qemu.conf                 |   8 +++
 src/qemu/qemu_command.c            | 133 +++++++++++++++++++++++++++----------
 src/qemu/qemu_command.h            |   1 -
 src/qemu/qemu_conf.c               |   3 +
 src/qemu/qemu_conf.h               |   1 +
 src/qemu/qemu_hotplug.c            |  25 +++----
 src/qemu/test_libvirtd_qemu.aug.in |   1 +
 src/util/virnetdevtap.c            |  33 +++++++++
 src/util/virnetdevtap.h            |   3 +
 src/util/virutil.c                 |  36 +++++++---
 12 files changed, 183 insertions(+), 63 deletions(-)

-- 
1.8.1.4




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