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apparmor/utils/apparmor/regex.py

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# ----------------------------------------------------------------------
# Copyright (C) 2013 Kshitij Gupta <kgupta8592@gmail.com>
# Copyright (C) 2014-2015 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.
#
# ----------------------------------------------------------------------
import re
from apparmor.common import AppArmorBug, AppArmorException
from apparmor.translations import init_translation
_ = init_translation()
# Profile parsing Regex
RE_AUDIT_DENY = r'^\s*(?P<audit>audit\s+)?(?P<allow>allow\s+|deny\s+)?' # line start, optionally: leading whitespace, <audit> and <allow>/deny
RE_EOL = r'\s*(?P<comment>#.*?)?\s*$' # optional whitespace, optional <comment>, optional whitespace, end of the line
RE_COMMA_EOL = r'\s*,' + RE_EOL # optional whitespace, comma + RE_EOL
RE_PROFILE_NAME = r'(?P<%s>(\S+|"[^"]+"))' # string without spaces, or quoted string. %s is the match group name
RE_PATH = r'/\S*|"/[^"]*"' # filename (starting with '/') without spaces, or quoted filename.
RE_PROFILE_PATH = '(?P<%s>(' + RE_PATH + '))' # quoted or unquoted filename. %s is the match group name
RE_PROFILE_PATH_OR_VAR = '(?P<%s>(' + RE_PATH + r'|@{\S+}\S*|"@{\S+}[^"]*"))' # quoted or unquoted filename or variable. %s is the match group name
RE_SAFE_OR_UNSAFE = '(?P<execmode>(safe|unsafe))'
RE_XATTRS = r'(\s+xattrs\s*=\s*\((?P<xattrs>([^)=]+(=[^)=]+)?\s?)+)\)\s*)?'
RE_FLAGS = r'(\s+(flags\s*=\s*)?\((?P<flags>[^)]+)\))?'
RE_PROFILE_END = re.compile(r'^\s*\}' + RE_EOL)
RE_PROFILE_ALL = re.compile(RE_AUDIT_DENY + r'all' + RE_COMMA_EOL)
RE_PROFILE_CAP = re.compile(RE_AUDIT_DENY + r'capability(?P<capability>(\s+\S+)+)?' + RE_COMMA_EOL)
RE_PROFILE_ALIAS = re.compile(r'^\s*alias\s+(?P<orig_path>"??.+?"??)\s+->\s*(?P<target>"??.+?"??)' + RE_COMMA_EOL)
RE_PROFILE_RLIMIT = re.compile(r'^\s*set\s+rlimit\s+(?P<rlimit>[a-z]+)\s*<=\s*(?P<value>[^ ]+(\s+[a-zA-Z]+)?)' + RE_COMMA_EOL)
RE_PROFILE_BOOLEAN = re.compile(r'^\s*(?P<varname>\$\{?\w*\}?)\s*=\s*(?P<value>true|false)\s*,?' + RE_EOL, flags=re.IGNORECASE)
RE_PROFILE_VARIABLE = re.compile(r'^\s*(?P<varname>@\{?\w+\}?)\s*(?P<mode>\+?=)\s*(?P<values>@*.+?)' + RE_EOL)
RE_PROFILE_CONDITIONAL = re.compile(r'^\s*if\s+(not\s+)?(\$\{?\w*\}?)\s*\{' + RE_EOL)
RE_PROFILE_CONDITIONAL_VARIABLE = re.compile(r'^\s*if\s+(not\s+)?defined\s+(@\{?\w+\}?)\s*\{\s*(#.*)?$')
RE_PROFILE_CONDITIONAL_BOOLEAN = re.compile(r'^\s*if\s+(not\s+)?defined\s+(\$\{?\w+\}?)\s*\{\s*(#.*)?$')
RE_PROFILE_NETWORK = re.compile(RE_AUDIT_DENY + r'network(?P<details>\s+.*)?' + RE_COMMA_EOL)
RE_PROFILE_CHANGE_HAT = re.compile(r'^\s*\^("??.+?"??)' + RE_COMMA_EOL)
RE_PROFILE_HAT_DEF = re.compile(r'^(?P<leadingspace>\s*)(?P<hat_keyword>\^|hat\s+)(?P<hat>"??[^)]+?"??)' + RE_FLAGS + r'\s*\{' + RE_EOL)
RE_PROFILE_DBUS = re.compile(RE_AUDIT_DENY + r'(dbus\s*,|dbus(?P<details>\s+[^#]*)\s*,)' + RE_EOL)
RE_PROFILE_MOUNT = re.compile(RE_AUDIT_DENY + r'((?P<operation>mount|remount|umount|unmount)(?P<details>\s+[^#]*)?\s*,)' + RE_EOL)
RE_PROFILE_SIGNAL = re.compile(RE_AUDIT_DENY + r'(signal\s*,|signal(?P<details>\s+[^#]*)\s*,)' + RE_EOL)
RE_PROFILE_PTRACE = re.compile(RE_AUDIT_DENY + r'(ptrace\s*,|ptrace(?P<details>\s+[^#]*)\s*,)' + RE_EOL)
RE_PROFILE_PIVOT_ROOT = re.compile(RE_AUDIT_DENY + r'(pivot_root\s*,|pivot_root\s+[^#]*\s*,)' + RE_EOL)
RE_PROFILE_UNIX = re.compile(RE_AUDIT_DENY + r'(unix\s*,|unix\s+[^#]*\s*,)' + RE_EOL)
RE_PROFILE_USERNS = re.compile(RE_AUDIT_DENY + r'(userns\s*,|userns(?P<details>\s+[^#]*)\s*,)' + RE_EOL)
RE_PROFILE_MQUEUE = re.compile(RE_AUDIT_DENY + r'(mqueue\s*,|mqueue(?P<details>\s+[^#]*)\s*,)' + RE_EOL)
RE_PROFILE_IO_URING = re.compile(RE_AUDIT_DENY + r'(io_uring\s*,|io_uring(?P<details>\s+[^#]*)\s*,)' + RE_EOL)
# match anything that's not " or #, or matching quotes with anything except quotes inside
__re_no_or_quoted_hash = '([^#"]|"[^"]*")*'
RE_RULE_HAS_COMMA = re.compile(
'^' + __re_no_or_quoted_hash
+ r',\s*(#.*)?$') # match comma plus any trailing comment
RE_HAS_COMMENT_SPLIT = re.compile(
'^(?P<not_comment>' + __re_no_or_quoted_hash + ')' # store in 'not_comment' group
+ '(?P<comment>#.*)$') # match trailing comment and store in 'comment' group
RE_PROFILE_START = re.compile(
r'^(?P<leadingspace>\s*)'
+ '('
+ RE_PROFILE_PATH_OR_VAR % 'plainprofile' # just a path
+ '|' # or
+ '(' + 'profile' + r'\s+' + RE_PROFILE_NAME % 'namedprofile' + r'(\s+' + RE_PROFILE_PATH_OR_VAR % 'attachment' + ')?' + ')' # 'profile', profile name, optionally attachment
+ ')'
+ RE_XATTRS
+ RE_FLAGS
+ r'\s*\{'
+ RE_EOL)
RE_PROFILE_CHANGE_PROFILE = re.compile(
RE_AUDIT_DENY
+ 'change_profile'
+ r'(\s+' + RE_SAFE_OR_UNSAFE + ')?' # optionally exec mode
+ r'(\s+' + RE_PROFILE_PATH_OR_VAR % 'execcond' + ')?' # optionally exec condition
+ r'(\s+->\s*' + RE_PROFILE_NAME % 'targetprofile' + ')?' # optionally '->' target profile
+ RE_COMMA_EOL)
# RE_PATH_PERMS is as restrictive as possible, but might still cause mismatches when adding different rule types.
# Therefore parsing code should match against file rules only after trying to match all other rule types.
RE_PATH_PERMS = '(?P<%s>[mrwalkPUCpucix]+)'
RE_PROFILE_FILE_ENTRY = re.compile(
RE_AUDIT_DENY
+ r'(?P<owner>owner\s+)?' # optionally: <owner>
+ '('
+ '(?P<bare_file>file)' # bare 'file,'
+ '|' # or
+ r'(?P<file_keyword>file\s+)?' # optional 'file' keyword
+ '('
+ RE_PROFILE_PATH_OR_VAR % 'path' + r'\s+' + RE_PATH_PERMS % 'perms' # path and perms
+ '|' # or
+ RE_PATH_PERMS % 'perms2' + r'\s+' + RE_PROFILE_PATH_OR_VAR % 'path2' # perms and path
+ ')'
+ r'(\s+->\s*' + RE_PROFILE_NAME % 'target' + ')?'
+ '|' # or
+ r'(?P<link_keyword>link\s+)' # 'link' keyword
+ r'(?P<subset_keyword>subset\s+)?' # optional 'subset' keyword
+ RE_PROFILE_PATH_OR_VAR % 'link_path' # path
+ r'\s+' + '->' + r'\s+' # ' -> '
+ RE_PROFILE_PATH_OR_VAR % 'link_target' # path
+ ')'
+ RE_COMMA_EOL)
def parse_profile_start_line(line, filename):
common_sections = ['leadingspace', 'flags', 'comment']
sections = ['plainprofile', 'namedprofile', 'attachment', 'xattrs'] + common_sections
matches = RE_PROFILE_START.search(line)
if not matches:
sections = ['hat_keyword', 'hat'] + common_sections
matches = RE_PROFILE_HAT_DEF.search(line)
if not matches:
raise AppArmorBug('The given line from file %(filename)s is not the start of a profile: %(line)s'
% {'filename': filename, 'line': line})
result = {}
for section in sections:
if matches.group(section):
result[section] = matches.group(section)
# sections with optional quotes
if section in ('plainprofile', 'namedprofile', 'attachment', 'hat'):
result[section] = strip_quotes(result[section])
else:
result[section] = None
if result['flags'] and not result['flags'].strip():
raise AppArmorException(
_('Invalid syntax in %(filename)s: Empty set of flags in line %(line)s.'
% {'filename': filename, 'line': line}))
result['is_hat'] = False
if result.get('hat'):
result['is_hat'] = True
result['profile'] = result['hat']
if result['hat_keyword'] == '^':
result['hat_keyword'] = False
else:
result['hat_keyword'] = True
result['profile_keyword'] = True
elif result['plainprofile']:
result['profile'] = result['plainprofile']
result['profile_keyword'] = False
else:
result['profile'] = result['namedprofile']
result['profile_keyword'] = True
return result
RE_MAGIC_OR_QUOTED_PATH = '(<(?P<magicpath>.*)>|"(?P<quotedpath>.*)"|(?P<unquotedpath>[^<>"]*))'
RE_ABI = re.compile(r'^\s*#?abi\s*' + RE_MAGIC_OR_QUOTED_PATH + RE_COMMA_EOL)
RE_INCLUDE = re.compile(r'^\s*#?include(?P<ifexists>\s+if\s+exists)?\s*' + RE_MAGIC_OR_QUOTED_PATH + RE_EOL)
def re_match_include_parse(line, rule_name):
"""Matches the path for include, include if exists and abi rules
rule_name can be 'include' or 'abi'
Returns a tuple with
- if the "if exists" condition is given
- the include/abi path
- if the path is a magic path (enclosed in <...>)
"""
if rule_name == 'include':
matches = RE_INCLUDE.search(line)
elif rule_name == 'abi':
matches = RE_ABI.search(line)
else:
raise AppArmorBug('re_match_include_parse() called with invalid rule name %s' % rule_name)
if not matches:
return None, None, None
path = None
ismagic = False
if matches.group('magicpath'):
path = matches.group('magicpath').strip()
ismagic = True
elif matches.group('unquotedpath'):
path = matches.group('unquotedpath').strip()
if re.search(r'\s', path):
raise AppArmorException(_('Syntax error: %s must use quoted path or <...>') % rule_name)
# LP: #1738879 - parser doesn't handle unquoted paths everywhere
if rule_name == 'include':
raise AppArmorException(_('Syntax error: %s must use quoted path or <...>') % rule_name)
elif matches.group('quotedpath'):
path = matches.group('quotedpath')
# LP: 1738880 - parser doesn't handle relative paths everywhere, and
# neither do we (see aa.py)
if rule_name == 'include' and path and not path.startswith('/'):
raise AppArmorException(_('Syntax error: %s must use quoted path or <...>') % rule_name)
if not path:
raise AppArmorException(_('Syntax error: %s rule with empty filename') % rule_name)
# LP: #1738877 - parser doesn't handle files with spaces in the name
if rule_name == 'include' and re.search(r'\s', path):
raise AppArmorException(_('Syntax error: %s rule filename cannot contain spaces') % rule_name)
ifexists = False
if rule_name == 'include' and matches.group('ifexists'):
ifexists = True
return path, ifexists, ismagic
def re_match_include(line):
"""return path of a 'include' rule"""
(path, ifexists, ismagic) = re_match_include_parse(line, 'include')
if not ifexists:
return path
return None
def strip_parenthesis(data):
"""strips parenthesis from the given string and returns the strip()ped result.
The parenthesis must be the first and last char, otherwise they won't be removed.
Even if no parenthesis get removed, the result will be strip()ped.
"""
if data.startswith('(') and data.endswith(')'):
return data[1:-1].strip()
else:
return data.strip()
def strip_quotes(data):
if len(data) > 1 and data.startswith('"') and data.endswith('"'):
return data[1:-1]
else:
return data
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