[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]

Re: [libvirt] [Qemu-devel] [PATCH v2 0/4] file descriptor passing using passfd

Please review this patch series if you could. I apologize for sending it more than once. Thanks!


On 06/08/2012 11:42 AM, Corey Bryant wrote:
libvirt's sVirt security driver provides SELinux MAC isolation for
Qemu guest processes and their corresponding image files.  In other
words, sVirt uses SELinux to prevent a QEMU process from opening
files that do not belong to it.

sVirt provides this support by labeling guests and resources with
security labels that are stored in file system extended attributes.
Some file systems, such as NFS, do not support the extended
attribute security namespace, and therefore cannot support sVirt

A solution to this problem is to provide fd passing support, where
libvirt opens files and passes file descriptors to QEMU.  This,
along with SELinux policy to prevent QEMU from opening files, can
provide image file isolation for NFS files stored on the same NFS

This patch series adds the passfd QMP monitor command, which allows
an fd to be passed via SCM_RIGHTS, and returns the received file
descriptor.  Support is also added to the block layer to allow QEMU
to dup the fd when the filename is of the /dev/fd/X format.  This
is useful if MAC policy prevents QEMU from opening specific types
of files.

One nice thing about this approach is that no new SELinux policy is
required to prevent open of NFS files (files with type nfs_t).  The
virt_use_nfs boolean type simply needs to be set to false, and open
will be prevented (and dup will be allowed).  For example:

     # setsebool virt_use_nfs 0
     # getsebool virt_use_nfs
     virt_use_nfs -->  off

Corey Bryant (4):
   qapi: Convert getfd and closefd
   qapi: Add passfd QMP command
   osdep: Enable qemu_open to dup pre-opened fd
   block: Convert open calls to qemu_open

  block/raw-posix.c |   18 +++++++++---------
  block/raw-win32.c |    4 ++--
  block/vdi.c       |    5 +++--
  block/vmdk.c      |   21 +++++++++------------
  block/vpc.c       |    2 +-
  block/vvfat.c     |   21 +++++++++++----------
  hmp-commands.hx   |    6 ++----
  hmp.c             |   18 ++++++++++++++++++
  hmp.h             |    2 ++
  monitor.c         |   36 ++++++++++++++++++++----------------
  osdep.c           |   13 +++++++++++++
  qapi-schema.json  |   44 ++++++++++++++++++++++++++++++++++++++++++++
  qmp-commands.hx   |   33 +++++++++++++++++++++++++++++----
  13 files changed, 163 insertions(+), 60 deletions(-)

[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]