qubespolicy: add a tool to analyze policy in form of graph

Output possible connections between VMs in form of dot file.

Fixes QubesOS/qubes-issues#2873

doc/manpages/qrexec_policy_graph.rst

@@ -0,0 +1,73 @@
+.. program:: qrexec-policy-graph
+
+:program:`qrexec-policy-graph` -- Graph qrexec policy
+=====================================================
+
+Synopsis
+--------
+
+:command:`qrexec-policy-graph` skel-manpage.py [-h] [--include-ask] [--source *SOURCE* [*SOURCE* ...]] [--target *TARGET* [*TARGET* ...]] [--service *SERVICE* [*SERVICE* ...]] [--output *OUTPUT*] [--policy-dir POLICY_DIR] [--system-info SYSTEM_INFO]
+
+
+Options
+-------
+
+.. option:: --help, -h
+
+   show this help message and exit
+
+.. option:: --include-ask
+
+   Include `ask` action in graph. In most cases produce unreadable graphs
+   because many services contains `$anyvm $anyvm ask` rules. It's recommended to
+   limit graph using other options.
+
+.. option:: --source
+
+   Limit graph to calls from *source*. You can specify multiple names.
+
+.. option:: --target
+
+   Limit graph to calls to *target*. You can specify multiple names.
+
+.. option:: --service
+
+   Limit graph to *service*. You can specify multiple names. This can be either
+   bare service name, or service with argument (joined with `+`). If bare
+   service name is given, output will contain also policies for specific
+   arguments.
+
+.. option:: --output
+
+   Write to *output* instead of stdout. The file will be overwritten without
+   confirmation.
+
+.. option:: --policy-dir
+
+   Look for policy in *policy-dir*. This can be useful to process policy
+   extracted from other system. This option adjust only base directory, if any
+   policy file contains `$include:path` with absolute path, it will try to load
+   the file from that location.
+   See also --system-info option.
+
+.. option:: --system-info
+
+   Load system information from file instead of querying local qubesd instance.
+   The file should be in json format, as returned by `internal.GetSystemInfo`
+   qubesd method. This can be obtained by running in dom0:
+
+        qubesd-query -e -c /var/run/qubesd.internal.sock dom0 \
+        internal.GetSystemInfo dom0 | cut -b 3-
+
+.. option:: --skip-labels
+
+   Do not include service names on the graph. Also, include only a single
+   connection between qubes if any service call is allowed there.
+
+
+Authors
+-------
+
+| Marek Marczykowski-Górecki <marmarek at invisiblethingslab dot com>
+
+.. vim: ts=3 sw=3 et tw=80

qubes-rpc-policy/generate-admin-policy

@@ -29,7 +29,7 @@ import qubes.api.admin
 parser = argparse.ArgumentParser(
     description='Generate default Admin API policy')
 parser.add_argument('--include-base', action='store',
-    default='/etc/qubes-rpc/policy/include',
+    default='include',
     help='Base path for included paths (default: %(default)s)')
 parser.add_argument('--destdir', action='store',
     default='/etc/qubes-rpc/policy',

qubespolicy/graph.py

@@ -0,0 +1,121 @@
+# -*- encoding: utf8 -*-
+#
+# The Qubes OS Project, http://www.qubes-os.org
+#
+# Copyright (C) 2017 Marek Marczykowski-Górecki
+#                               <[email protected]>
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with this program; if not, see <http://www.gnu.org/licenses/>.
+
+import argparse
+import json
+import os
+
+import sys
+
+import qubespolicy
+
+parser = argparse.ArgumentParser(description='Graph qrexec policy')
+parser.add_argument('--include-ask', action='store_true',
+    help='Include `ask` action in graph')
+parser.add_argument('--source', action='store', nargs='+',
+    help='Limit graph to calls from *source*')
+parser.add_argument('--target', action='store', nargs='+',
+    help='Limit graph to calls to *target*')
+parser.add_argument('--service', action='store', nargs='+',
+    help='Limit graph to *service*')
+parser.add_argument('--output', action='store',
+    help='Write to *output* instead of stdout')
+parser.add_argument('--policy-dir', action='store',
+    default=qubespolicy.POLICY_DIR,
+    help='Look for policy in *policy-dir*')
+parser.add_argument('--system-info', action='store',
+    help='Load system information from file instead of querying qubesd')
+parser.add_argument('--skip-labels', action='store_true',
+    help='Do not include service names on the graph, also deduplicate '
+         'connections.')
+
+def handle_single_action(args, action):
+    '''Get single policy action and output (or not) a line to add'''
+    if args.skip_labels:
+        service = ''
+    else:
+        service = action.service
+    if action.action == qubespolicy.Action.ask:
+        if args.include_ask:
+            # handle forced target=
+            if len(action.targets_for_ask) == 1:
+                return '  "{}" -> "{}" [label="{}" color=orange];\n'.format(
+                    action.source, action.targets_for_ask[0], service)
+            else:
+                return '  "{}" -> "{}" [label="{}" color=orange];\n'.format(
+                    action.source, action.original_target, service)
+    elif action.action == qubespolicy.Action.allow:
+        return '  "{}" -> "{}" [label="{}" color=red];\n'.format(
+                action.source, action.target, service)
+    return ''
+
+def main(args=None):
+    args = parser.parse_args(args)
+
+    output = sys.stdout
+    if args.output:
+        output = open(args.output, 'w')
+
+    if args.system_info:
+        with open(args.system_info) as f_system_info:
+            system_info = json.load(f_system_info)
+    else:
+        system_info = qubespolicy.get_system_info()
+
+    sources = list(system_info['domains'].keys())
+    if args.source:
+        sources = args.source
+
+    targets = list(system_info['domains'].keys())
+    if args.target:
+        targets = args.target
+    else:
+        targets.append('$dispvm')
+        targets.extend('$dispvm:' + dom for dom in system_info['domains']
+            if system_info['domains'][dom]['dispvm_allowed'])
+
+    connections = set()
+
+    output.write('digraph g {\n')
+    for service in os.listdir(args.policy_dir):
+        if args.service and service not in args.service and \
+                not any(service.startswith(srv + '+') for srv in args.service):
+            continue
+
+        policy = qubespolicy.Policy(service, args.policy_dir)
+        for source in sources:
+            for target in targets:
+                try:
+                    action = policy.evaluate(system_info, source, target)
+                    line = handle_single_action(args, action)
+                    if line in connections:
+                        continue
+                    if line:
+                        output.write(line)
+                    connections.add(line)
+                except qubespolicy.AccessDenied:
+                    continue
+
+    output.write('}\n')
+    if args.output:
+        output.close()
+
+if __name__ == '__main__':
+    sys.exit(main())

rpm_spec/core-dom0.spec

@@ -213,6 +213,7 @@ fi
 /usr/bin/qubesd*
 /usr/bin/qrexec-policy
 /usr/bin/qrexec-policy-agent
+/usr/bin/qrexec-policy-graph
 
 %{_mandir}/man1/qubes*.1*
 
@@ -372,6 +373,7 @@ fi
 %{python3_sitelib}/qubespolicy/gtkhelpers.py
 %{python3_sitelib}/qubespolicy/rpcconfirmation.py
 %{python3_sitelib}/qubespolicy/utils.py
+%{python3_sitelib}/qubespolicy/graph.py
 
 %dir %{python3_sitelib}/qubespolicy/tests
 %dir %{python3_sitelib}/qubespolicy/tests/__pycache__

setup.py

@@ -34,6 +34,7 @@ def get_console_scripts():
             'console_scripts': list(get_console_scripts()) + [
                 'qrexec-policy = qubespolicy.cli:main',
                 'qrexec-policy-agent = qubespolicy.agent:main',
+                'qrexec-policy-graph = qubespolicy.graph:main',
             ],
             'qubes.vm': [
                 'AppVM = qubes.vm.appvm:AppVM',