/usr/lib/python3/dist-packages/apparmor/rule/__init__.py is in python3-apparmor 2.10.95-0ubuntu2.6~14.04.4.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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# Copyright (C) 2013 Kshitij Gupta <kgupta8592@gmail.com>
# Copyright (C) 2014 Christian Boltz <apparmor@cboltz.de>
#
# 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 as published by the Free Software Foundation.
#
# 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.
#
# ----------------------------------------------------------------------
from apparmor.aare import AARE
from apparmor.common import AppArmorBug, type_is_str
# setup module translations
from apparmor.translations import init_translation
_ = init_translation()
class BaseRule(object):
'''Base class to handle and store a single rule'''
# type specific rules should inherit from this class.
# Methods that subclasses need to implement:
# __init__
# _match(cls, raw_rule) (as a class method)
# - parses a raw rule and returns a regex match object
# _parse(cls, raw_rule) (as a class method)
# - parses a raw rule and returns an object of the Rule subclass
# get_clean(depth)
# - return rule in clean format
# is_covered(self, other_rule)
# - check if other_rule is covered by this rule (i.e. is a
# subset of this rule's permissions)
# is_equal_localvars(self, other_rule)
# - equality check for the rule-specific fields
def __init__(self, audit=False, deny=False, allow_keyword=False,
comment='', log_event=None):
'''initialize variables needed by all rule types'''
self.audit = audit
self.deny = deny
self.allow_keyword = allow_keyword
self.comment = comment
self.log_event = log_event
# Set only in the parse() class method
self.raw_rule = None
def _aare_or_all(self, rulepart, partname, is_path, log_event):
'''checks rulepart and returns
- (AARE, False) if rulepart is a (non-empty) string
- (None, True) if rulepart is all_obj (typically *Rule.ALL)
- raises AppArmorBug if rulepart is an empty string or has a wrong type
Parameters:
- rulepart: the rule part to check (string or *Rule.ALL object)
- partname: the name of the rulepart (for example 'peer', used for exception messages)
- is_path (passed through to AARE)
- log_event (passed through to AARE)
'''
if rulepart == self.ALL:
return None, True
elif type_is_str(rulepart):
if len(rulepart.strip()) == 0:
raise AppArmorBug('Passed empty %(partname)s to %(classname)s: %(rulepart)s' %
{'partname': partname, 'classname': self.__class__.__name__, 'rulepart': str(rulepart)})
return AARE(rulepart, is_path=is_path, log_event=log_event), False
else:
raise AppArmorBug('Passed unknown %(partname)s to %(classname)s: %(rulepart)s'
% {'partname': partname, 'classname': self.__class__.__name__, 'rulepart': str(rulepart)})
def __repr__(self):
classname = self.__class__.__name__
try:
raw_content = self.get_raw() # will fail for BaseRule
return '<%s> %s' % (classname, raw_content)
except NotImplementedError:
return '<%s (NotImplementedError - get_clean() not implemented?)>' % classname
@classmethod
def match(cls, raw_rule):
'''return True if raw_rule matches the class (main) regex, False otherwise
Note: This function just provides an answer to "is this your job?".
It does not guarantee that the rule is completely valid.'''
if cls._match(raw_rule):
return True
else:
return False
# @abstractmethod FIXME - uncomment when python3 only
@classmethod
def _match(cls, raw_rule):
'''parse raw_rule and return regex match object'''
raise NotImplementedError("'%s' needs to implement _match(), but didn't" % (str(cls)))
@classmethod
def parse(cls, raw_rule):
'''parse raw_rule and return a rule object'''
rule = cls._parse(raw_rule)
rule.raw_rule = raw_rule.strip()
return rule
# @abstractmethod FIXME - uncomment when python3 only
@classmethod
def _parse(cls, raw_rule):
'''returns a Rule object created from parsing the raw rule.
required to be implemented by subclasses; raise exception if not'''
raise NotImplementedError("'%s' needs to implement _parse(), but didn't" % (str(cls)))
# @abstractmethod FIXME - uncomment when python3 only
def get_clean(self, depth=0):
'''return clean rule (with default formatting, and leading whitespace as specified in the depth parameter)'''
raise NotImplementedError("'%s' needs to implement get_clean(), but didn't" % (str(self.__class__)))
def get_raw(self, depth=0):
'''return raw rule (with original formatting, and leading whitespace in the depth parameter)'''
if self.raw_rule:
return '%s%s' % (' ' * depth, self.raw_rule)
else:
return self.get_clean(depth)
def is_covered(self, other_rule, check_allow_deny=True, check_audit=False):
'''check if other_rule is covered by this rule object'''
if not type(other_rule) == type(self):
raise AppArmorBug('Passes %s instead of %s' % (str(other_rule),self.__class__.__name__))
if check_allow_deny and self.deny != other_rule.deny:
return False
if other_rule.deny and not self.deny:
return False
if check_audit and other_rule.audit != self.audit:
return False
if other_rule.audit and not self.audit:
return False
# still here? -> then the common part is covered, check rule-specific things now
return self.is_covered_localvars(other_rule)
# @abstractmethod FIXME - uncomment when python3 only
def is_covered_localvars(self, other_rule):
'''check if the rule-specific parts of other_rule is covered by this rule object'''
raise NotImplementedError("'%s' needs to implement is_covered_localvars(), but didn't" % (str(self)))
def _is_covered_plain(self, self_value, self_all, other_value, other_all, cond_name):
'''check if other_* is covered by self_* - for plain str, int etc.'''
if not other_value and not other_all:
raise AppArmorBug('No %(cond_name)s specified in other %(rule_name)s rule' % {'cond_name': cond_name, 'rule_name': self.rule_name})
if not self_all:
if other_all:
return False
if self_value != other_value:
return False
# still here? -> then it is covered
return True
def _is_covered_list(self, self_value, self_all, other_value, other_all, cond_name):
'''check if other_* is covered by self_* - for lists'''
if not other_value and not other_all:
raise AppArmorBug('No %(cond_name)s specified in other %(rule_name)s rule' % {'cond_name': cond_name, 'rule_name': self.rule_name})
if not self_all:
if other_all:
return False
if not other_value.issubset(self_value):
return False
# still here? -> then it is covered
return True
def _is_covered_aare(self, self_value, self_all, other_value, other_all, cond_name):
'''check if other_* is covered by self_* - for AARE'''
if not other_value and not other_all:
raise AppArmorBug('No %(cond_name)s specified in other %(rule_name)s rule' % {'cond_name': cond_name, 'rule_name': self.rule_name})
if not self_all:
if other_all:
return False
if not self_value.match(other_value.regex): # XXX should check against other_value (without .regex) - but that gives different (more strict) results
return False
# still here? -> then it is covered
return True
def is_equal(self, rule_obj, strict=False):
'''compare if rule_obj == self
Calls is_equal_localvars() to compare rule-specific variables'''
if self.audit != rule_obj.audit or self.deny != rule_obj.deny:
return False
if strict and (
self.allow_keyword != rule_obj.allow_keyword
or self.comment != rule_obj.comment
or self.raw_rule != rule_obj.raw_rule
):
return False
return self.is_equal_localvars(rule_obj)
def _is_equal_aare(self, self_value, self_all, other_value, other_all, cond_name):
'''check if other_* is the same as self_* - for AARE'''
if not other_value and not other_all:
raise AppArmorBug('No %(cond_name)s specified in other %(rule_name)s rule' % {'cond_name': cond_name, 'rule_name': self.rule_name})
if self_all != other_all:
return False
if self_value and not self_value.is_equal(other_value):
return False
# still here? -> then it is equal
return True
# @abstractmethod FIXME - uncomment when python3 only
def is_equal_localvars(self, other_rule):
'''compare if rule-specific variables are equal'''
raise NotImplementedError("'%s' needs to implement is_equal_localvars(), but didn't" % (str(self)))
def severity(self, sev_db):
'''return severity of this rule, which can be:
- a number between 0 and 10, where 0 means harmless and 10 means critical,
- "unknown" (to be exact: the value specified for "unknown" as set when loading the severity database), or
- sev_db.NOT_IMPLEMENTED if no severity check is implemented for this rule type.
sev_db must be an apparmor.severity.Severity object.'''
return sev_db.NOT_IMPLEMENTED
def logprof_header(self):
'''return the headers (human-readable version of the rule) to display in aa-logprof for this rule object
returns {'label1': 'value1', 'label2': 'value2'} '''
headers = []
qualifier = []
if self.audit:
qualifier += ['audit']
if self.deny:
qualifier += ['deny']
elif self.allow_keyword:
qualifier += ['allow']
if qualifier:
headers += [_('Qualifier'), ' '.join(qualifier)]
headers += self.logprof_header_localvars()
return headers
# @abstractmethod FIXME - uncomment when python3 only
def logprof_header_localvars(self):
'''return the headers (human-readable version of the rule) to display in aa-logprof for this rule object
returns {'label1': 'value1', 'label2': 'value2'} '''
raise NotImplementedError("'%s' needs to implement logprof_header(), but didn't" % (str(self)))
def modifiers_str(self):
'''return the allow/deny and audit keyword as string, including whitespace'''
if self.audit:
auditstr = 'audit '
else:
auditstr = ''
if self.deny:
allowstr = 'deny '
elif self.allow_keyword:
allowstr = 'allow '
else:
allowstr = ''
return '%s%s' % (auditstr, allowstr)
class BaseRuleset(object):
'''Base class to handle and store a collection of rules'''
# decides if the (G)lob and Glob w/ (E)xt options are displayed
can_glob = True
can_glob_ext = False
def __init__(self):
'''initialize variables needed by all ruleset types
Do not override in child class unless really needed - override _init_vars() instead'''
self.rules = []
self._init_vars()
def _init_vars(self):
'''called by __init__() and delete_all_rules() - override in child class to initialize more variables'''
pass
def __repr__(self):
classname = self.__class__.__name__
if self.rules:
return '<%s>\n' % classname + '\n'.join(self.get_raw(1)) + '</%s>' % classname
else:
return '<%s (empty) />' % classname
def add(self, rule):
'''add a rule object'''
self.rules.append(rule)
def get_raw(self, depth=0):
'''return all raw rules (if possible/not modified in their original formatting).
Returns an array of lines, with depth * leading whitespace'''
data = []
for rule in self.rules:
data.append(rule.get_raw(depth))
if data:
data.append('')
return data
def get_clean(self, depth=0):
'''return all rules (in clean/default formatting)
Returns an array of lines, with depth * leading whitespace'''
allow_rules = []
deny_rules = []
for rule in self.rules:
if rule.deny:
deny_rules.append(rule.get_clean(depth))
else:
allow_rules.append(rule.get_clean(depth))
allow_rules.sort()
deny_rules.sort()
cleandata = []
if deny_rules:
cleandata += deny_rules
cleandata.append('')
if allow_rules:
cleandata += allow_rules
cleandata.append('')
return cleandata
def is_covered(self, rule, check_allow_deny=True, check_audit=False):
'''return True if rule is covered by existing rules, otherwise False'''
for r in self.rules:
if r.is_covered(rule, check_allow_deny, check_audit):
return True
return False
# def is_log_covered(self, parsed_log_event, check_allow_deny=True, check_audit=False):
# '''return True if parsed_log_event is covered by existing rules, otherwise False'''
#
# rule_obj = self.new_rule()
# rule_obj.set_log(parsed_log_event)
#
# return self.is_covered(rule_obj, check_allow_deny, check_audit)
def delete(self, rule):
'''Delete rule from rules'''
rule_to_delete = False
i = 0
for r in self.rules:
if r.is_equal(rule):
rule_to_delete = True
break
i = i + 1
if rule_to_delete:
self.rules.pop(i)
else:
raise AppArmorBug('Attempt to delete non-existing rule %s' % rule.get_raw(0))
def delete_duplicates(self, include_rules):
'''Delete duplicate rules.
include_rules must be a *_rules object or None'''
deleted = 0
# delete rules that are covered by include files
if include_rules:
for rule in self.rules:
if include_rules.is_covered(rule, True, True):
self.delete(rule)
deleted += 1
# de-duplicate rules inside the profile
deleted += self.delete_in_profile_duplicates()
self.rules.reverse()
deleted += self.delete_in_profile_duplicates() # search again in reverse order - this will find the remaining duplicates
self.rules.reverse() # restore original order for raw output
return deleted
def delete_in_profile_duplicates(self):
'''Delete duplicate rules inside a profile'''
deleted = 0
oldrules = self.rules
self.rules = []
for rule in oldrules:
if not self.is_covered(rule, True, False):
self.rules.append(rule)
else:
deleted += 1
return deleted
def get_glob_ext(self, path_or_rule):
'''returns the next possible glob with extension (for file rules only).
For all other rule types, raise an exception'''
raise NotImplementedError("get_glob_ext is not available for this rule type!")
def check_and_split_list(lst, allowed_keywords, all_obj, classname, keyword_name):
'''check if lst is all_obj or contains only items listed in allowed_keywords'''
if lst == all_obj:
return None, True, None
elif type_is_str(lst):
result_list = {lst}
elif (type(lst) == list or type(lst) == tuple) and len(lst) > 0:
result_list = set(lst)
else:
raise AppArmorBug('Passed unknown %(type)s object to %(classname)s: %(unknown_object)s' %
{'type': type(lst), 'classname': classname, 'unknown_object': str(lst)})
unknown_items = set()
for item in result_list:
if not item.strip():
raise AppArmorBug('Passed empty %(keyword_name)s to %(classname)s' %
{'keyword_name': keyword_name, 'classname': classname})
if item not in allowed_keywords:
unknown_items.add(item)
return result_list, False, unknown_items
def logprof_value_or_all(value, all_values):
'''helper for logprof_header() to return 'all' (if all_values is True) or the specified value.
For some types, the value is made more readable.'''
if all_values:
return _('ALL')
if type(value) == AARE:
return value.regex
elif type(value) == set or type(value) == list or type(value) == tuple:
return ' '.join(sorted(value))
else:
return value
def parse_comment(matches):
'''returns the comment (with a leading space) from the matches object'''
comment = ''
if matches.group('comment'):
# include a space so that we don't need to add it everywhere when writing the rule
comment = ' %s' % matches.group('comment')
return comment
def parse_modifiers(matches):
'''returns audit, deny, allow_keyword and comment from the matches object
- audit, deny and allow_keyword are True/False
- comment is the comment with a leading space'''
audit = False
if matches.group('audit'):
audit = True
deny = False
allow_keyword = False
allowstr = matches.group('allow')
if allowstr:
if allowstr.strip() == 'allow':
allow_keyword = True
elif allowstr.strip() == 'deny':
deny = True
else:
raise AppArmorBug("Invalid allow/deny keyword %s" % allowstr)
comment = parse_comment(matches)
return (audit, deny, allow_keyword, comment)
def quote_if_needed(data):
'''quote data if it contains whitespace'''
if ' ' in data:
data = '"' + data + '"'
return data
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