utils: Basic support for ptrace rules

Bug: https://bugs.launchpad.net/bugs/1300317

This patch does bare bones parsing of ptrace rules and stores the raw
strings for writing them out later. It is meant to be a simple change to
prevent aa.py from emitting a traceback when encountering ptrace rules.

Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Acked-by: Steve Beattie <steve@nxnw.org>
Acked-By: Christian Boltz <apparmor@cboltz.de>

utils/apparmor/aa.py

@@ -2625,6 +2625,7 @@ RE_NETWORK_FAMILY = re.compile('\s+(\S+)\s*,$')
 RE_PROFILE_DBUS = re.compile('^\s*(audit\s+)?(allow\s+|deny\s+)?(dbus[^#]*\s*,)\s*(#.*)?$')
 RE_PROFILE_MOUNT = re.compile('^\s*(audit\s+)?(allow\s+|deny\s+)?((mount|remount|umount)[^#]*\s*,)\s*(#.*)?$')
 RE_PROFILE_SIGNAL = re.compile('^\s*(audit\s+)?(allow\s+|deny\s+)?((signal)[^#]*\s*,)\s*(#.*)?$')
+RE_PROFILE_PTRACE = re.compile('^\s*(audit\s+)?(allow\s+|deny\s+)?((ptrace)[^#]*\s*,)\s*(#.*)?$')
 
 # match anything that's not " or #, or matching quotes with anything except quotes inside
 __re_no_or_quoted_hash = '([^#"]|"[^"]*")*'
@@ -2704,6 +2705,7 @@ def parse_profile_data(data, file, do_include):
             profile_data[profile][hat]['allow']['dbus'] = list()
             profile_data[profile][hat]['allow']['mount'] = list()
             profile_data[profile][hat]['allow']['signal'] = list()
+            profile_data[profile][hat]['allow']['ptrace'] = list()
             # Save the initial comment
             if initial_comment:
                 profile_data[profile][hat]['initial_comment'] = initial_comment
@@ -3086,6 +3088,28 @@ def parse_profile_data(data, file, do_include):
             signal_rules.append(signal_rule)
             profile_data[profile][hat][allow]['signal'] = signal_rules
 
+        elif RE_PROFILE_PTRACE.search(line):
+            matches = RE_PROFILE_PTRACE.search(line).groups()
+
+            if not profile:
+                raise AppArmorException(_('Syntax Error: Unexpected ptrace entry found in file: %s line: %s') % (file, lineno + 1))
+
+            audit = False
+            if matches[0]:
+                audit = True
+            allow = 'allow'
+            if matches[1] and matches[1].strip() == 'deny':
+                allow = 'deny'
+            ptrace = matches[2].strip()
+
+            ptrace_rule = parse_ptrace_rule(ptrace)
+            ptrace_rule.audit = audit
+            ptrace_rule.deny = (allow == 'deny')
+
+            ptrace_rules = profile_data[profile][hat][allow].get('ptrace', list())
+            ptrace_rules.append(ptrace_rule)
+            profile_data[profile][hat][allow]['ptrace'] = ptrace_rules
+
         elif RE_PROFILE_CHANGE_HAT.search(line):
             matches = RE_PROFILE_CHANGE_HAT.search(line).groups()
 
@@ -3188,6 +3212,10 @@ def parse_signal_rule(line):
     # XXX Do real parsing here
     return aarules.Raw_Signal_Rule(line)
 
+def parse_ptrace_rule(line):
+    # XXX Do real parsing here
+    return aarules.Raw_Ptrace_Rule(line)
+
 def separate_vars(vs):
     """Returns a list of all the values for a variable"""
     data = []
@@ -3435,6 +3463,24 @@ def write_signal(prof_data, depth):
     data += write_signal_rules(prof_data, depth, 'allow')
     return data
 
+def write_ptrace_rules(prof_data, depth, allow):
+    pre = '  ' * depth
+    data = []
+
+    # no ptrace rules, so return
+    if not prof_data[allow].get('ptrace', False):
+        return data
+
+    for ptrace_rule in prof_data[allow]['ptrace']:
+        data.append('%s%s' % (pre, ptrace_rule.serialize()))
+    data.append('')
+    return data
+
+def write_ptrace(prof_data, depth):
+    data = write_ptrace_rules(prof_data, depth, 'deny')
+    data += write_ptrace_rules(prof_data, depth, 'allow')
+    return data
+
 def write_link_rules(prof_data, depth, allow):
     pre = '  ' * depth
     data = []
@@ -3542,6 +3588,7 @@ def write_rules(prof_data, depth):
     data += write_dbus(prof_data, depth)
     data += write_mount(prof_data, depth)
     data += write_signal(prof_data, depth)
+    data += write_ptrace(prof_data, depth)
     data += write_links(prof_data, depth)
     data += write_paths(prof_data, depth)
     data += write_change_profile(prof_data, depth)
@@ -3692,6 +3739,7 @@ def serialize_profile_from_old_profile(profile_data, name, options):
                          'dbus': write_dbus,
                          'mount': write_mount,
                          'signal': write_signal,
+                         'ptrace': write_ptrace,
                          'link': write_links,
                          'path': write_paths,
                          'change_profile': write_change_profile,
@@ -3785,6 +3833,7 @@ def serialize_profile_from_old_profile(profile_data, name, options):
                     data += write_dbus(write_prof_data[name], depth)
                     data += write_mount(write_prof_data[name], depth)
                     data += write_signal(write_prof_data[name], depth)
+                    data += write_ptrace(write_prof_data[name], depth)
                     data += write_links(write_prof_data[name], depth)
                     data += write_paths(write_prof_data[name], depth)
                     data += write_change_profile(write_prof_data[name], depth)

utils/apparmor/rules.py

@@ -79,3 +79,15 @@ class Raw_Signal_Rule(object):
         return "%s%s%s" % ('audit ' if self.audit else '',
                            'deny '  if self.deny else '',
                            self.rule)
+
+class Raw_Ptrace_Rule(object):
+    audit = False
+    deny = False
+
+    def __init__(self, rule):
+        self.rule = rule
+
+    def serialize(self):
+        return "%s%s%s" % ('audit ' if self.audit else '',
+                           'deny '  if self.deny else '',
+                           self.rule)

utils/test/test-ptrace_parse.py

@@ -0,0 +1,53 @@
+#! /usr/bin/env python
+# ------------------------------------------------------------------
+#
+#    Copyright (C) 2014 Canonical Ltd.
+#
+#    This program is free software; you can redistribute it and/or
+#    modify it under the terms of version 2 of the GNU General Public
+#    License published by the Free Software Foundation.
+#
+# ------------------------------------------------------------------
+
+import apparmor.aa as aa
+import unittest
+
+class AAParsePtraceTest(unittest.TestCase):
+
+    def _test_parse_ptrace_rule(self, rule):
+        ptrace = aa.parse_ptrace_rule(rule)
+        self.assertEqual(rule, ptrace.serialize(),
+                'ptrace object returned "%s", expected "%s"' % (ptrace.serialize(), rule))
+
+    def test_parse_plain_ptrace_rule(self):
+        self._test_parse_ptrace_rule('ptrace,')
+
+    def test_parse_readby_ptrace_rule(self):
+        self._test_parse_ptrace_rule('ptrace (readby),')
+
+    def test_parse_trace_ptrace_rule(self):
+        self._test_parse_ptrace_rule('ptrace (trace),')
+
+    def test_parse_trace_read_ptrace_rule(self):
+        self._test_parse_ptrace_rule('ptrace (trace read),')
+
+    def test_parse_r_ptrace_rule(self):
+        self._test_parse_ptrace_rule('ptrace r,')
+
+    def test_parse_w_ptrace_rule(self):
+        self._test_parse_ptrace_rule('ptrace w,')
+
+    def test_parse_rw_ptrace_rule(self):
+        self._test_parse_ptrace_rule('ptrace rw,')
+
+    def test_parse_peer_1_ptrace_rule(self):
+        self._test_parse_ptrace_rule('ptrace read peer=foo,')
+
+    def test_parse_peer_2_ptrace_rule(self):
+        self._test_parse_ptrace_rule('ptrace (trace read) peer=/usr/bin/bar,')
+
+    def test_parse_peer_3_ptrace_rule(self):
+        self._test_parse_ptrace_rule('ptrace wr peer=/sbin/baz,')
+
+if __name__ == '__main__':
+    unittest.main()

utils/test/test-regex_matches.py

@@ -48,6 +48,11 @@ regex_has_comma_testcases = [
     ('signal (send, receive)%s', 'embedded parens signal 01'),
     ('signal (send, receive) set=(hup, quit)%s', 'embedded parens signal 02'),
 
+    ('ptrace%s', 'bare ptrace'),
+    ('ptrace trace%s', 'simple ptrace'),
+    ('ptrace (tracedby, readby)%s', 'embedded parens ptrace 01'),
+    ('ptrace (trace) peer=/usr/bin/foo%s', 'embedded parens ptrace 02'),
+
     # the following fail due to inadequacies in the regex
     # ('dbus (r, w, %s', 'incomplete dbus action'),
     # ('member="{Hello,AddMatch,RemoveMatch, %s', 'incomplete {} regex'),  # also invalid policy
@@ -106,6 +111,8 @@ regex_split_comment_testcases = [
     ('file /tmp/foo rw, # read-write', ('file /tmp/foo rw, ', '# read-write')),
     ('signal, # comment', ('signal, ', '# comment')),
     ('signal receive set=(usr1 usr2) peer=foo,', False),
+    ('ptrace, # comment', ('ptrace, ', '# comment')),
+    ('ptrace (trace read) peer=/usr/bin/foo,', False),
 ]
 
 def setup_split_comment_testcases():
@@ -365,6 +372,77 @@ class AARegexSignal(unittest.TestCase):
         self.assertEqual(parsed, rule, 'Expected signal rule "%s", got "%s"'
                          % (rule, parsed))
 
+class AARegexPtrace(unittest.TestCase):
+    '''Tests for RE_PROFILE_PTRACE'''
+
+    def test_bare_ptrace_01(self):
+        '''test '   ptrace,' '''
+
+        rule = 'ptrace,'
+        line = '   %s' % rule
+        result = aa.RE_PROFILE_PTRACE.search(line)
+        self.assertTrue(result, 'Couldn\'t find ptrace rule in "%s"' % line)
+        parsed = result.groups()[2].strip()
+        self.assertEqual(parsed, rule, 'Expected ptrace rule "%s", got "%s"'
+                         % (rule, parsed))
+
+    def test_bare_ptrace_02(self):
+        '''test '   audit ptrace,' '''
+
+        rule = 'ptrace,'
+        line = '   audit %s' % rule
+        result = aa.RE_PROFILE_PTRACE.search(line)
+        self.assertTrue(result, 'Couldn\'t find ptrace rule in "%s"' % line)
+        self.assertTrue(result.groups()[0], 'Couldn\'t find audit modifier in "%s"' % line)
+        parsed = result.groups()[2].strip()
+        self.assertEqual(parsed, rule, 'Expected ptrace rule "%s", got "%s"'
+                         % (rule, parsed))
+
+    def test_simple_ptrace_01(self):
+        '''test '   ptrace trace,' '''
+
+        rule = 'ptrace trace,'
+        line = '   %s' % rule
+        result = aa.RE_PROFILE_PTRACE.search(line)
+        self.assertTrue(result, 'Couldn\'t find ptrace rule in "%s"' % line)
+        parsed = result.groups()[2].strip()
+        self.assertEqual(parsed, rule, 'Expected ptrace rule "%s", got "%s"'
+                         % (rule, parsed))
+
+    def test_simple_ptrace_02(self):
+        '''test '   ptrace (tracedby, readby),' '''
+
+        rule = 'ptrace (tracedby, readby),'
+        line = '   %s' % rule
+        result = aa.RE_PROFILE_PTRACE.search(line)
+        self.assertTrue(result, 'Couldn\'t find ptrace rule in "%s"' % line)
+        parsed = result.groups()[2].strip()
+        self.assertEqual(parsed, rule, 'Expected ptrace rule "%s", got "%s"'
+                         % (rule, parsed))
+
+    def test_simple_ptrace_03(self):
+        '''test '   audit ptrace (read),' '''
+
+        rule = 'ptrace (read),'
+        line = '   audit %s' % rule
+        result = aa.RE_PROFILE_PTRACE.search(line)
+        self.assertTrue(result, 'Couldn\'t find ptrace rule in "%s"' % line)
+        self.assertTrue(result.groups()[0], 'Couldn\'t find audit modifier in "%s"' % line)
+        parsed = result.groups()[2].strip()
+        self.assertEqual(parsed, rule, 'Expected ptrace rule "%s", got "%s"'
+                         % (rule, parsed))
+
+    def test_peer_ptrace_01(self):
+        '''test '   ptrace trace peer=/usr/sbin/daemon,' '''
+
+        rule = 'ptrace trace peer=/usr/sbin/daemon,'
+        line = '   %s' % rule
+        result = aa.RE_PROFILE_PTRACE.search(line)
+        self.assertTrue(result, 'Couldn\'t find ptrace rule in "%s"' % line)
+        parsed = result.groups()[2].strip()
+        self.assertEqual(parsed, rule, 'Expected ptrace rule "%s", got "%s"'
+                         % (rule, parsed))
+
 if __name__ == '__main__':
     verbosity = 2
 
@@ -378,6 +456,7 @@ if __name__ == '__main__':
     test_suite.addTest(unittest.TestLoader().loadTestsFromTestCase(AARegexPath))
     test_suite.addTest(unittest.TestLoader().loadTestsFromTestCase(AARegexFile))
     test_suite.addTest(unittest.TestLoader().loadTestsFromTestCase(AARegexSignal))
+    test_suite.addTest(unittest.TestLoader().loadTestsFromTestCase(AARegexPtrace))
     result = unittest.TextTestRunner(verbosity=verbosity).run(test_suite)
     if not result.wasSuccessful():
         exit(1)