Exemplo n.º 1
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def _validatePath(path, perms):
  """Validate a disk image or other ifle.

  _validatePath makes sure that the user requesting a privileged
  operation would have permission to interact with the file in
  question.

  Args:
    disk: A path to a disk image
    perms: A bitmask composed of os.R_OK, os.W_OK, and/or os.X_OK

  Raises:
    debmarshal.errors.AccessDenied if the unprivileged user doesn't
      have permission to interact with the path using perms.
  """
  # Start by setting the process uid to getCaller(). This is primarily
  # done to make sure we're respecting the abstraction introduced by
  # getCaller().
  #
  # This won't guarantee that we have the necessary bits for, e.g.,
  # AFS, where you need a separate token to prove your identity, but
  # it would work for most other cases.
  old_uid = os.getuid()
  os.setreuid(utils.getCaller(), 0)

  try:
    if not os.access(path, perms):
      raise errors.AccessDenied('UID %s does not have access to %s.' %
                                (utils.getCaller(), path))
  finally:
    # Reset the process uid that we changed earlier.
    os.setuid(old_uid)
Exemplo n.º 2
0
def _validateNetwork(net, virt_con=None):
  """Validate a debmarshal network.

  This function checks that the network name passed in is a network
  known to (i.e. created by) debmarshal. It also verifies that the
  network was created by the user calling the function.

  Args:
    net: The name of the debmarshal network.
    virt_con: A read-only libvirt.virConnect instance. We'll open one
      of our own if one isn't passed in. Since libvirt network
      information is shared across all hypervisors, virt_con can be a
      connection to any libvirt driver.

  Raises:
    debmarshal.errors.NetworkNotFound if the named network doesn't
      exist.
    debmarshal.errors.AccessDenied if the network isn't owned by the
      caller.
  """
  if not virt_con:
    virt_con = libvirt.open('qemu:///system')

  nets = networks.loadNetworkState(virt_con)

  if net not in nets:
    raise errors.NetworkNotFound("Network %s does not exist." % net)

  if nets[net] != utils.getCaller():
    raise errors.AccessDenied("Network %s is not owned by UID %s." %
      (net, utils.getCaller()))
Exemplo n.º 3
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  def testWrongUser(self):
    """Wrong user leads to an AcccessDenied exception."""
    self.mox.StubOutWithMock(utils, 'getCaller')
    utils.getCaller().MultipleTimes().AndReturn(500)

    self.mox.ReplayAll()

    self.assertRaises(errors.AccessDenied, domains._validateNetwork,
                      'debmarshal-1', self.virt_con)
Exemplo n.º 4
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  def testValidNetwork(self):
    """Valid network name from the right caller passes validation."""
    self.mox.StubOutWithMock(utils, 'getCaller')
    utils.getCaller().MultipleTimes().AndReturn(500)

    self.mox.ReplayAll()

    # Once again, we want a self.assertNoRaises, or something, but it
    # doesn't exist, so we just run the code
    domains._validateNetwork('debmarshal-0', self.virt_con)
Exemplo n.º 5
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  def testNoConnection(self):
    """_validateNetwork is able to open its own libvirt connection."""
    self.mox.StubOutWithMock(libvirt, 'open')
    libvirt.open(mox.IgnoreArg()).AndReturn(self.virt_con)

    self.mox.StubOutWithMock(utils, 'getCaller')
    utils.getCaller().MultipleTimes().AndReturn(500)

    self.mox.ReplayAll()

    domains._validateNetwork('debmarshal-0')
Exemplo n.º 6
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  def setUp(self):
    """Setup the getuid/setuid dance."""
    super(TestValidatePath, self).setUp()

    self.mox.StubOutWithMock(os, 'getuid')
    self.mox.StubOutWithMock(os, 'setreuid')
    self.mox.StubOutWithMock(os, 'setuid')
    self.mox.StubOutWithMock(utils, 'getCaller')

    os.getuid().MultipleTimes().AndReturn(0)
    utils.getCaller().MultipleTimes().AndReturn(500)
    os.setreuid(500, 0)
    os.setuid(0)