[virt-tools-list] [virt-install PATCH v2] Support multiple seclabels

[Martin Kletzander]

Until now, virt-install supported only one seclabel and it was the
first one libvirt reported in capabilities.  This patch adds support
for more of them and also adds a functionality to try to match the
right one from the label given.  This is done by checking how many
colons the label has (precisely said, to how many parts it is split
by the colons).
---

I checked this without label as well as with selinux and DAC labels
and all worked as expected for me.  However DAC labels in libvirt
0.10.2 are supported only as uid:gid (e.g. 107:36), but that should be
handled in upper layers as we cannot know that the user/group exist on
remote machine.  Newer versions of libvirt (>1.0.0) support user:group
(e.g. qemu:kvm) completely.

v2:
 - Changed according to Cole's suggestions

 virtinst/CapabilitiesParser.py | 10 +++++++---
 virtinst/Seclabel.py           | 36 ++++++++++++++++++++++++++++++++----
 virtinst/VirtualDisk.py        |  8 ++------
 3 files changed, 41 insertions(+), 13 deletions(-)

diff --git a/virtinst/CapabilitiesParser.py b/virtinst/CapabilitiesParser.py
index 4c1398c..6585a15 100644
--- a/virtinst/CapabilitiesParser.py
+++ b/virtinst/CapabilitiesParser.py
@@ -1,7 +1,7 @@
 #
 # Some code for parsing libvirt's capabilities XML
 #
-# Copyright 2007  Red Hat, Inc.
+# Copyright 2007, 2012  Red Hat, Inc.
 # Mark McLoughlin <markmc at redhat.com>
 #
 # This program is free software; you can redistribute it and/or modify
@@ -260,11 +260,15 @@ class Host(object):
     def __init__(self, node=None):
         self.cpu = CPU()
         self.topology = None
-        self.secmodel = None
+        self.secmodels = []

         if not node is None:
             self.parseXML(node)

+    def get_secmodel(self):
+        return self.secmodels and self.secmodels[0] or None
+    secmodel = property(get_secmodel)
+
     # Back compat for CPU class
     def get_arch(self):
         return self.cpu.arch
@@ -285,7 +289,7 @@ class Host(object):
                 self.topology = Topology(child)

             if child.name == "secmodel":
-                self.secmodel = SecurityModel(child)
+                self.secmodels.append(SecurityModel(child))

             if child.name == "cpu":
                 self.cpu = CPU(child)
diff --git a/virtinst/Seclabel.py b/virtinst/Seclabel.py
index 7682664..8b3a199 100644
--- a/virtinst/Seclabel.py
+++ b/virtinst/Seclabel.py
@@ -1,5 +1,5 @@
 #
-# Copyright 2010  Red Hat, Inc.
+# Copyright 2010, 2012  Red Hat, Inc.
 # Cole Robinson <crobinso at redhat.com>
 #
 # This program is free software; you can redistribute it and/or modify
@@ -32,6 +32,11 @@ class Seclabel(XMLBuilderDomain.XMLBuilderDomain):

     MODEL_DEFAULT = "default"

+    SECLABEL_MODEL_SELINUX = "selinux"
+    SECLABEL_MODEL_DAC = "dac"
+    SECLABEL_MODEL_NONE = "none"
+    SECLABEL_MODELS = [ SECLABEL_MODEL_SELINUX, SECLABEL_MODEL_DAC, SECLABEL_MODEL_NONE ]
+
     _dumpxml_xpath = "/domain/seclabel"
     def __init__(self, conn, parsexml=None, parsexmlnode=None, caps=None):
         XMLBuilderDomain.XMLBuilderDomain.__init__(self, conn, parsexml,
@@ -50,7 +55,30 @@ class Seclabel(XMLBuilderDomain.XMLBuilderDomain):
         self.type = self.SECLABEL_TYPE_DEFAULT

     def _get_default_model(self):
-        return self._get_caps().host.secmodel.model
+        for model in self.SECLABEL_MODELS:
+            if model in [x.model for x in self._get_caps().host.secmodels]:
+                return model
+        raise RuntimeError("No supported model found in capabilities")
+
+    def _guess_secmodel(self, label, imagelabel):
+        if not label and not imagelabel:
+            return self._get_default_model()
+
+        lab_len = imglab_len = None
+        if label:
+            lab_len = min(3, len(label.split(':')))
+        if imagelabel:
+            imglab_len = min(3, len(imagelabel.split(':')))
+        if lab_len and imglab_len and lab_len != imglab_len:
+            raise ValueError("Label and Imagelabel are incompatible")
+
+        lab_len = lab_len or imglab_len
+        if lab_len == 3:
+            return self.SECLABEL_MODEL_SELINUX
+        elif lab_len == 2:
+            return self.SECLABEL_MODEL_DAC
+        else:
+            raise ValueError("Unknown model type for label '%s'" % self.label)

     def get_type(self):
         return self._type
@@ -100,8 +128,6 @@ class Seclabel(XMLBuilderDomain.XMLBuilderDomain):
         typ = self.type
         relabel = self.relabel

-        if model == self.MODEL_DEFAULT:
-            model = self._get_default_model()
         if typ == self.SECLABEL_TYPE_DEFAULT:
             typ = self.SECLABEL_TYPE_DYNAMIC

@@ -113,6 +139,8 @@ class Seclabel(XMLBuilderDomain.XMLBuilderDomain):
                 raise RuntimeError("A label must be specified for static "
                                    "security type.")

+        if model == self.MODEL_DEFAULT:
+            model = self._guess_secmodel(self.label, self.imagelabel)

         label_xml = ""
         xml = "  <seclabel type='%s' model='%s'" % (typ, model)
diff --git a/virtinst/VirtualDisk.py b/virtinst/VirtualDisk.py
index 2eeb43d..b5812b4 100644
--- a/virtinst/VirtualDisk.py
+++ b/virtinst/VirtualDisk.py
@@ -1,7 +1,7 @@
 #
 # Classes for building disk device xml
 #
-# Copyright 2006-2008  Red Hat, Inc.
+# Copyright 2006-2008, 2012  Red Hat, Inc.
 # Jeremy Katz <katzj at redhat.com>
 #
 # This program is free software; you can redistribute it and/or modify
@@ -1620,11 +1620,7 @@ class VirtualDisk(VirtualDevice):
         for selinux commands
         """
         caps = self._get_caps()
-        if (not caps and False):
-            #caps.host.secmodel is None or
-            #caps.host.secmodel.model != "selinux"):
-            # XXX: Libvirt support isn't strictly required, but all the
-            #      our label guesses are built with svirt in mind
+        if "selinux" not in [x.model for x in caps.host.secmodels]:
             return False

         elif self.is_remote():
--
1.8.0