4 # pylint: disable=missing-module-docstring,missing-class-docstring,missing-function-docstring
5 # pylint: disable=line-too-long,invalid-name,too-many-branches,too-many-statements
7 This tool helps me to check Linux kernel options against
8 my security hardening preferences for X86_64, ARM64, X86_32, and ARM.
9 Let the computers do their job!
11 Author: Alexander Popov <alex.popov@linux.com>
13 This module performs input/output.
18 from argparse import ArgumentParser
19 from collections import OrderedDict
22 from .__about__ import __version__
23 from .checks import add_kconfig_checks, add_cmdline_checks, normalize_cmdline_options
24 from .engine import populate_with_data, perform_checks
27 def detect_arch(fname, archs):
28 with open(fname, 'r', encoding='utf-8') as f:
29 arch_pattern = re.compile("CONFIG_[a-zA-Z0-9_]*=y")
31 for line in f.readlines():
32 if arch_pattern.match(line):
33 option, _ = line[7:].split('=', 1)
38 return None, 'more than one supported architecture is detected'
40 return None, 'failed to detect architecture'
44 def detect_kernel_version(fname):
45 with open(fname, 'r', encoding='utf-8') as f:
46 ver_pattern = re.compile("# Linux/.* Kernel Configuration")
47 for line in f.readlines():
48 if ver_pattern.match(line):
52 ver_numbers = ver_str.split('.')
53 if len(ver_numbers) < 3 or not ver_numbers[0].isdigit() or not ver_numbers[1].isdigit():
54 msg = 'failed to parse the version "' + ver_str + '"'
56 return (int(ver_numbers[0]), int(ver_numbers[1])), None
57 return None, 'no kernel version detected'
60 def detect_compiler(fname):
63 with open(fname, 'r', encoding='utf-8') as f:
64 gcc_version_pattern = re.compile("CONFIG_GCC_VERSION=[0-9]*")
65 clang_version_pattern = re.compile("CONFIG_CLANG_VERSION=[0-9]*")
66 for line in f.readlines():
67 if gcc_version_pattern.match(line):
68 gcc_version = line[19:-1]
69 if clang_version_pattern.match(line):
70 clang_version = line[21:-1]
71 if not gcc_version or not clang_version:
72 return None, 'no CONFIG_GCC_VERSION or CONFIG_CLANG_VERSION'
73 if gcc_version == '0' and clang_version != '0':
74 return 'CLANG ' + clang_version, 'OK'
75 if gcc_version != '0' and clang_version == '0':
76 return 'GCC ' + gcc_version, 'OK'
77 sys.exit(f'[!] ERROR: invalid GCC_VERSION and CLANG_VERSION: {gcc_version} {clang_version}')
80 def print_unknown_options(checklist, parsed_options):
84 if o1.type != 'complex':
85 known_options.append(o1.name)
88 if o2.type != 'complex':
89 if hasattr(o2, 'name'):
90 known_options.append(o2.name)
93 assert(o3.type != 'complex'), \
94 f'unexpected ComplexOptCheck inside {o2.name}'
95 if hasattr(o3, 'name'):
96 known_options.append(o3.name)
98 for option, value in parsed_options.items():
99 if option not in known_options:
100 print(f'[?] No check for option {option} ({value})')
103 def print_checklist(mode, checklist, with_results):
107 output.append(o.json_dump(with_results))
108 print(json.dumps(output))
115 print('=' * sep_line_len)
116 print(f"{'option name':^40}|{'type':^7}|{'desired val':^12}|{'decision':^10}|{'reason':^18}", end='')
118 print('| check result', end='')
120 print('=' * sep_line_len)
123 for opt in checklist:
125 if mode == 'show_ok':
126 if not opt.result.startswith('OK'):
128 if mode == 'show_fail':
129 if not opt.result.startswith('FAIL'):
131 opt.table_print(mode, with_results)
133 if mode == 'verbose':
134 print('-' * sep_line_len)
139 fail_count = len(list(filter(lambda opt: opt.result.startswith('FAIL'), checklist)))
141 ok_count = len(list(filter(lambda opt: opt.result.startswith('OK'), checklist)))
143 if mode == 'show_ok':
144 fail_suppressed = ' (suppressed in output)'
145 if mode == 'show_fail':
146 ok_suppressed = ' (suppressed in output)'
148 print(f'[+] Config check is finished: \'OK\' - {ok_count}{ok_suppressed} / \'FAIL\' - {fail_count}{fail_suppressed}')
151 def parse_kconfig_file(parsed_options, fname):
152 with open(fname, 'r', encoding='utf-8') as f:
153 opt_is_on = re.compile("CONFIG_[a-zA-Z0-9_]*=[a-zA-Z0-9_\"]*")
154 opt_is_off = re.compile("# CONFIG_[a-zA-Z0-9_]* is not set")
156 for line in f.readlines():
161 if opt_is_on.match(line):
162 option, value = line.split('=', 1)
163 if value == 'is not set':
164 sys.exit(f'[!] ERROR: bad enabled kconfig option "{line}"')
165 elif opt_is_off.match(line):
166 option, value = line[2:].split(' ', 1)
167 if value != 'is not set':
168 sys.exit(f'[!] ERROR: bad disabled kconfig option "{line}"')
170 if option in parsed_options:
171 sys.exit(f'[!] ERROR: kconfig option "{line}" exists multiple times')
174 parsed_options[option] = value
177 def parse_cmdline_file(parsed_options, fname):
178 with open(fname, 'r', encoding='utf-8') as f:
184 sys.exit(f'[!] ERROR: more than one line in "{fname}"')
188 name, value = opt.split('=', 1)
191 value = '' # '' is not None
192 value = normalize_cmdline_options(name, value)
193 parsed_options[name] = value
199 # - reporting about unknown kernel options in the kconfig
200 # - verbose printing of ComplexOptCheck items
201 # * json mode for printing the results in JSON format
202 report_modes = ['verbose', 'json', 'show_ok', 'show_fail']
203 supported_archs = ['X86_64', 'X86_32', 'ARM64', 'ARM']
204 parser = ArgumentParser(prog='kconfig-hardened-check',
205 description='A tool for checking the security hardening options of the Linux kernel')
206 parser.add_argument('--version', action='version', version='%(prog)s ' + __version__)
207 parser.add_argument('-p', '--print', choices=supported_archs,
208 help='print security hardening preferences for the selected architecture')
209 parser.add_argument('-c', '--config',
210 help='check the kernel kconfig file against these preferences')
211 parser.add_argument('-l', '--cmdline',
212 help='check the kernel cmdline file against these preferences')
213 parser.add_argument('-m', '--mode', choices=report_modes,
214 help='choose the report mode')
215 args = parser.parse_args()
221 print(f'[+] Special report mode: {mode}')
223 config_checklist = []
227 sys.exit('[!] ERROR: --config and --print can\'t be used together')
230 print(f'[+] Kconfig file to check: {args.config}')
232 print(f'[+] Kernel cmdline file to check: {args.cmdline}')
234 arch, msg = detect_arch(args.config, supported_archs)
236 sys.exit(f'[!] ERROR: {msg}')
238 print(f'[+] Detected architecture: {arch}')
240 kernel_version, msg = detect_kernel_version(args.config)
241 if not kernel_version:
242 sys.exit(f'[!] ERROR: {msg}')
244 print(f'[+] Detected kernel version: {kernel_version[0]}.{kernel_version[1]}')
246 compiler, msg = detect_compiler(args.config)
249 print(f'[+] Detected compiler: {compiler}')
251 print(f'[-] Can\'t detect the compiler: {msg}')
253 # add relevant kconfig checks to the checklist
254 add_kconfig_checks(config_checklist, arch)
257 # add relevant cmdline checks to the checklist
258 add_cmdline_checks(config_checklist, arch)
260 # populate the checklist with the parsed kconfig data
261 parsed_kconfig_options = OrderedDict()
262 parse_kconfig_file(parsed_kconfig_options, args.config)
263 populate_with_data(config_checklist, parsed_kconfig_options, 'kconfig')
264 populate_with_data(config_checklist, kernel_version, 'version')
267 # populate the checklist with the parsed kconfig data
268 parsed_cmdline_options = OrderedDict()
269 parse_cmdline_file(parsed_cmdline_options, args.cmdline)
270 populate_with_data(config_checklist, parsed_cmdline_options, 'cmdline')
272 # now everything is ready, perform the checks
273 perform_checks(config_checklist)
275 if mode == 'verbose':
276 # print the parsed options without the checks (for debugging)
277 all_parsed_options = parsed_kconfig_options # assignment does not copy
279 all_parsed_options.update(parsed_cmdline_options)
280 print_unknown_options(config_checklist, all_parsed_options)
282 # finally print the results
283 print_checklist(mode, config_checklist, True)
287 sys.exit('[!] ERROR: checking cmdline doesn\'t work without checking kconfig')
290 if mode in ('show_ok', 'show_fail'):
291 sys.exit(f'[!] ERROR: wrong mode "{mode}" for --print')
293 add_kconfig_checks(config_checklist, arch)
294 add_cmdline_checks(config_checklist, arch)
296 print(f'[+] Printing kernel security hardening preferences for {arch}...')
297 print_checklist(mode, config_checklist, False)