4 # This tool helps me to check Linux kernel options against
5 # my security hardening preferences for X86_64, ARM64, X86_32, and ARM.
6 # Let the computers do their job!
8 # Author: Alexander Popov <alex.popov@linux.com>
10 # Please don't cry if my Python code looks like C.
13 # N.B Hardening command line parameters:
15 # page_alloc.shuffle=1
16 # iommu=force (does it help against DMA attacks?)
19 # slub_debug=FZ (slow)
20 # init_on_alloc=1 (since v5.3)
21 # init_on_free=1 (since v5.3, otherwise slub_debug=P and page_poison=1)
23 # debugfs=no-mount (or off if possible)
24 # randomize_kstack_offset=1
26 # Mitigations of CPU vulnerabilities:
28 # mitigations=auto,nosmt (nosmt is slow)
32 # spec_store_bypass_disable=on
34 # l1d_flush=on (a part of the l1tf option)
46 # Hardware tag-based KASAN with arm64 Memory Tagging Extension (MTE):
48 # kasan.stacktrace=off
51 # N.B. Hardening sysctls:
52 # kernel.kptr_restrict=2 (or 1?)
53 # kernel.dmesg_restrict=1 (also see the kconfig option)
54 # kernel.perf_event_paranoid=3
55 # kernel.kexec_load_disabled=1
56 # kernel.yama.ptrace_scope=3
57 # user.max_user_namespaces=0
58 # what about bpf_jit_enable?
59 # kernel.unprivileged_bpf_disabled=1
60 # net.core.bpf_jit_harden=2
62 # vm.unprivileged_userfaultfd=0
63 # (at first, it disabled unprivileged userfaultfd,
64 # and since v5.11 it enables unprivileged userfaultfd for user-mode only)
66 # dev.tty.ldisc_autoload=0
67 # fs.protected_symlinks=1
68 # fs.protected_hardlinks=1
69 # fs.protected_fifos=2
70 # fs.protected_regular=2
72 # kernel.modules_disabled=1
75 # pylint: disable=missing-module-docstring,missing-class-docstring,missing-function-docstring
76 # pylint: disable=line-too-long,invalid-name,too-many-branches,too-many-statements
80 from argparse import ArgumentParser
81 from collections import OrderedDict
84 from .__about__ import __version__
86 TYPES_OF_CHECKS = ('kconfig', 'version')
89 def __init__(self, reason, decision, name, expected):
91 self.expected = expected
92 self.decision = decision
98 if self.expected == self.state:
100 elif self.state is None:
101 if self.expected == 'is not set':
102 self.result = 'OK: not found'
104 self.result = 'FAIL: not found'
106 self.result = 'FAIL: "' + self.state + '"'
108 def table_print(self, _mode, with_results):
109 print('{:<40}|{:^7}|{:^12}|{:^10}|{:^18}'.format(self.name, self.type, self.expected, self.decision, self.reason), end='')
111 print('| {}'.format(self.result), end='')
114 class KconfigCheck(OptCheck):
115 def __init__(self, *args, **kwargs):
116 super().__init__(*args, **kwargs)
117 self.name = 'CONFIG_' + self.name
123 def json_dump(self, with_results):
124 dump = [self.name, self.type, self.expected, self.decision, self.reason]
126 dump.append(self.result)
131 def __init__(self, ver_expected):
132 self.ver_expected = ver_expected
141 if self.ver[0] > self.ver_expected[0]:
142 self.result = 'OK: version >= ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
144 if self.ver[0] < self.ver_expected[0]:
145 self.result = 'FAIL: version < ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
147 if self.ver[1] >= self.ver_expected[1]:
148 self.result = 'OK: version >= ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
150 self.result = 'FAIL: version < ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
152 def table_print(self, _mode, with_results):
153 ver_req = 'kernel version >= ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
154 print('{:<91}'.format(ver_req), end='')
156 print('| {}'.format(self.result), end='')
160 def __init__(self, name, type):
162 if self.type == 'kconfig':
163 self.name = 'CONFIG_' + name
165 sys.exit('[!] ERROR: unsupported type "{}" for {}'.format(type, self.__class__.__name__))
170 if self.state is None:
171 self.result = 'FAIL: not present'
173 self.result = 'OK: is present'
175 def table_print(self, _mode, with_results):
176 print('{:<91}'.format(self.name + ' is present'), end='')
178 print('| {}'.format(self.result), end='')
181 class ComplexOptCheck:
182 def __init__(self, *opts):
185 sys.exit('[!] ERROR: empty {} check'.format(self.__class__.__name__))
186 if len(self.opts) == 1:
187 sys.exit('[!] ERROR: useless {} check'.format(self.__class__.__name__))
188 if not isinstance(opts[0], KconfigCheck):
189 sys.exit('[!] ERROR: invalid {} check: {}'.format(self.__class__.__name__, opts))
194 return self.opts[0].name
202 return self.opts[0].expected
206 return self.opts[0].decision
210 return self.opts[0].reason
212 def table_print(self, mode, with_results):
213 if mode == 'verbose':
214 print(' {:87}'.format('<<< ' + self.__class__.__name__ + ' >>>'), end='')
216 print('| {}'.format(self.result), end='')
219 o.table_print(mode, with_results)
222 o.table_print(mode, False)
224 print('| {}'.format(self.result), end='')
226 def json_dump(self, with_results):
227 dump = self.opts[0].json_dump(False)
229 dump.append(self.result)
233 class OR(ComplexOptCheck):
234 # self.opts[0] is the option that this OR-check is about.
236 # OR(<X_is_hardened>, <X_is_disabled>)
237 # OR(<X_is_hardened>, <old_X_is_hardened>)
240 sys.exit('[!] ERROR: invalid OR check')
241 for i, opt in enumerate(self.opts):
243 if opt.result.startswith('OK'):
244 if opt.result == 'OK' and i != 0:
245 # Simple OK is not enough for additional checks, add more info:
246 self.result = 'OK: {} "{}"'.format(opt.name, opt.expected)
248 self.result = opt.result
250 self.result = self.opts[0].result
253 class AND(ComplexOptCheck):
254 # self.opts[0] is the option that this AND-check is about.
256 # AND(<suboption>, <main_option>)
257 # Suboption is not checked if checking of the main_option is failed.
258 # AND(<X_is_disabled>, <old_X_is_disabled>)
260 for i, opt in reversed(list(enumerate(self.opts))):
263 self.result = opt.result
265 if not opt.result.startswith('OK'):
266 # This FAIL is caused by additional checks,
267 # and not by the main option that this AND-check is about.
268 # Describe the reason of the FAIL.
269 if opt.result.startswith('FAIL: \"') or opt.result == 'FAIL: not found':
270 self.result = 'FAIL: {} not "{}"'.format(opt.name, opt.expected)
271 elif opt.result == 'FAIL: not present':
272 self.result = 'FAIL: {} not present'.format(opt.name)
274 # This FAIL message is self-explaining.
275 self.result = opt.result
277 sys.exit('[!] ERROR: invalid AND check')
280 def detect_arch(fname, archs):
281 with open(fname, 'r') as f:
282 arch_pattern = re.compile("CONFIG_[a-zA-Z0-9_]*=y")
284 for line in f.readlines():
285 if arch_pattern.match(line):
286 option, _ = line[7:].split('=', 1)
291 return None, 'more than one supported architecture is detected'
293 return None, 'failed to detect architecture'
297 def detect_version(fname):
298 with open(fname, 'r') as f:
299 ver_pattern = re.compile("# Linux/.* Kernel Configuration")
300 for line in f.readlines():
301 if ver_pattern.match(line):
305 ver_numbers = ver_str.split('.')
306 if len(ver_numbers) < 3 or not ver_numbers[0].isdigit() or not ver_numbers[1].isdigit():
307 msg = 'failed to parse the version "' + ver_str + '"'
309 return (int(ver_numbers[0]), int(ver_numbers[1])), None
310 return None, 'no kernel version detected'
313 def add_kconfig_checks(l, arch):
314 # Calling the KconfigCheck class constructor:
315 # KconfigCheck(reason, decision, name, expected)
317 modules_not_set = KconfigCheck('cut_attack_surface', 'kspp', 'MODULES', 'is not set')
318 devmem_not_set = KconfigCheck('cut_attack_surface', 'kspp', 'DEVMEM', 'is not set') # refers to LOCKDOWN
319 bpf_syscall_not_set = KconfigCheck('cut_attack_surface', 'lockdown', 'BPF_SYSCALL', 'is not set') # refers to LOCKDOWN
320 efi_not_set = KconfigCheck('cut_attack_surface', 'my', 'EFI', 'is not set')
322 # 'self_protection', 'defconfig'
323 l += [KconfigCheck('self_protection', 'defconfig', 'BUG', 'y')]
324 l += [KconfigCheck('self_protection', 'defconfig', 'SLUB_DEBUG', 'y')]
325 l += [KconfigCheck('self_protection', 'defconfig', 'GCC_PLUGINS', 'y')]
326 l += [OR(KconfigCheck('self_protection', 'defconfig', 'STACKPROTECTOR_STRONG', 'y'),
327 KconfigCheck('self_protection', 'defconfig', 'CC_STACKPROTECTOR_STRONG', 'y'))]
328 l += [OR(KconfigCheck('self_protection', 'defconfig', 'STRICT_KERNEL_RWX', 'y'),
329 KconfigCheck('self_protection', 'defconfig', 'DEBUG_RODATA', 'y'))] # before v4.11
330 l += [OR(KconfigCheck('self_protection', 'defconfig', 'STRICT_MODULE_RWX', 'y'),
331 KconfigCheck('self_protection', 'defconfig', 'DEBUG_SET_MODULE_RONX', 'y'),
332 modules_not_set)] # DEBUG_SET_MODULE_RONX was before v4.11
333 l += [OR(KconfigCheck('self_protection', 'defconfig', 'REFCOUNT_FULL', 'y'),
334 VersionCheck((5, 5)))] # REFCOUNT_FULL is enabled by default since v5.5
335 l += [KconfigCheck('self_protection', 'defconfig', 'THREAD_INFO_IN_TASK', 'y')]
336 iommu_support_is_set = KconfigCheck('self_protection', 'defconfig', 'IOMMU_SUPPORT', 'y')
337 l += [iommu_support_is_set] # is needed for mitigating DMA attacks
338 if arch in ('X86_64', 'ARM64', 'X86_32'):
339 l += [KconfigCheck('self_protection', 'defconfig', 'RANDOMIZE_BASE', 'y')]
340 if arch in ('X86_64', 'ARM64'):
341 l += [KconfigCheck('self_protection', 'defconfig', 'VMAP_STACK', 'y')]
342 if arch in ('X86_64', 'X86_32'):
343 l += [KconfigCheck('self_protection', 'defconfig', 'MICROCODE', 'y')] # is needed for mitigating CPU bugs
344 l += [KconfigCheck('self_protection', 'defconfig', 'RETPOLINE', 'y')]
345 l += [KconfigCheck('self_protection', 'defconfig', 'X86_SMAP', 'y')]
346 l += [KconfigCheck('self_protection', 'defconfig', 'SYN_COOKIES', 'y')] # another reason?
347 l += [OR(KconfigCheck('self_protection', 'defconfig', 'X86_UMIP', 'y'),
348 KconfigCheck('self_protection', 'defconfig', 'X86_INTEL_UMIP', 'y'))]
349 if arch in ('ARM64', 'ARM'):
350 l += [KconfigCheck('self_protection', 'defconfig', 'STACKPROTECTOR_PER_TASK', 'y')]
352 l += [KconfigCheck('self_protection', 'defconfig', 'PAGE_TABLE_ISOLATION', 'y')]
353 l += [KconfigCheck('self_protection', 'defconfig', 'RANDOMIZE_MEMORY', 'y')]
354 l += [AND(KconfigCheck('self_protection', 'defconfig', 'INTEL_IOMMU', 'y'),
355 iommu_support_is_set)]
356 l += [AND(KconfigCheck('self_protection', 'defconfig', 'AMD_IOMMU', 'y'),
357 iommu_support_is_set)]
359 l += [KconfigCheck('self_protection', 'defconfig', 'ARM64_PAN', 'y')]
360 l += [KconfigCheck('self_protection', 'defconfig', 'ARM64_EPAN', 'y')]
361 l += [KconfigCheck('self_protection', 'defconfig', 'UNMAP_KERNEL_AT_EL0', 'y')]
362 l += [OR(KconfigCheck('self_protection', 'defconfig', 'HARDEN_EL2_VECTORS', 'y'),
363 AND(KconfigCheck('self_protection', 'defconfig', 'RANDOMIZE_BASE', 'y'),
364 VersionCheck((5, 9))))] # HARDEN_EL2_VECTORS was included in RANDOMIZE_BASE in v5.9
365 l += [KconfigCheck('self_protection', 'defconfig', 'RODATA_FULL_DEFAULT_ENABLED', 'y')]
366 l += [KconfigCheck('self_protection', 'defconfig', 'ARM64_PTR_AUTH_KERNEL', 'y')]
367 l += [KconfigCheck('self_protection', 'defconfig', 'ARM64_BTI_KERNEL', 'y')]
368 l += [OR(KconfigCheck('self_protection', 'defconfig', 'HARDEN_BRANCH_PREDICTOR', 'y'),
369 VersionCheck((5, 10)))] # HARDEN_BRANCH_PREDICTOR is enabled by default since v5.10
370 l += [KconfigCheck('self_protection', 'defconfig', 'MITIGATE_SPECTRE_BRANCH_HISTORY', 'y')]
371 l += [KconfigCheck('self_protection', 'defconfig', 'ARM64_MTE', 'y')]
373 l += [KconfigCheck('self_protection', 'defconfig', 'CPU_SW_DOMAIN_PAN', 'y')]
374 l += [KconfigCheck('self_protection', 'defconfig', 'HARDEN_BRANCH_PREDICTOR', 'y')]
375 l += [KconfigCheck('self_protection', 'defconfig', 'HARDEN_BRANCH_HISTORY', 'y')]
377 # 'self_protection', 'kspp'
378 l += [KconfigCheck('self_protection', 'kspp', 'SECURITY_DMESG_RESTRICT', 'y')]
379 l += [KconfigCheck('self_protection', 'kspp', 'BUG_ON_DATA_CORRUPTION', 'y')]
380 l += [KconfigCheck('self_protection', 'kspp', 'DEBUG_WX', 'y')]
381 l += [KconfigCheck('self_protection', 'kspp', 'SCHED_STACK_END_CHECK', 'y')]
382 l += [KconfigCheck('self_protection', 'kspp', 'SLAB_FREELIST_HARDENED', 'y')]
383 l += [KconfigCheck('self_protection', 'kspp', 'SLAB_FREELIST_RANDOM', 'y')]
384 l += [KconfigCheck('self_protection', 'kspp', 'SHUFFLE_PAGE_ALLOCATOR', 'y')]
385 l += [KconfigCheck('self_protection', 'kspp', 'FORTIFY_SOURCE', 'y')]
386 l += [KconfigCheck('self_protection', 'kspp', 'DEBUG_LIST', 'y')]
387 l += [KconfigCheck('self_protection', 'kspp', 'DEBUG_SG', 'y')]
388 l += [KconfigCheck('self_protection', 'kspp', 'DEBUG_CREDENTIALS', 'y')]
389 l += [KconfigCheck('self_protection', 'kspp', 'DEBUG_NOTIFIERS', 'y')]
390 l += [KconfigCheck('self_protection', 'kspp', 'INIT_ON_ALLOC_DEFAULT_ON', 'y')]
391 l += [KconfigCheck('self_protection', 'kspp', 'GCC_PLUGIN_LATENT_ENTROPY', 'y')]
392 l += [KconfigCheck('self_protection', 'kspp', 'KFENCE', 'y')]
393 l += [KconfigCheck('self_protection', 'kspp', 'WERROR', 'y')]
394 l += [KconfigCheck('self_protection', 'kspp', 'IOMMU_DEFAULT_DMA_STRICT', 'y')]
395 randstruct_is_set = KconfigCheck('self_protection', 'kspp', 'GCC_PLUGIN_RANDSTRUCT', 'y')
396 l += [randstruct_is_set]
397 hardened_usercopy_is_set = KconfigCheck('self_protection', 'kspp', 'HARDENED_USERCOPY', 'y')
398 l += [hardened_usercopy_is_set]
399 l += [AND(KconfigCheck('self_protection', 'kspp', 'HARDENED_USERCOPY_FALLBACK', 'is not set'),
400 hardened_usercopy_is_set)]
401 l += [AND(KconfigCheck('self_protection', 'kspp', 'HARDENED_USERCOPY_PAGESPAN', 'is not set'),
402 hardened_usercopy_is_set)]
403 l += [OR(KconfigCheck('self_protection', 'kspp', 'MODULE_SIG', 'y'),
405 l += [OR(KconfigCheck('self_protection', 'kspp', 'MODULE_SIG_ALL', 'y'),
407 l += [OR(KconfigCheck('self_protection', 'kspp', 'MODULE_SIG_SHA512', 'y'),
409 l += [OR(KconfigCheck('self_protection', 'kspp', 'MODULE_SIG_FORCE', 'y'),
410 modules_not_set)] # refers to LOCKDOWN
411 l += [OR(KconfigCheck('self_protection', 'kspp', 'INIT_STACK_ALL_ZERO', 'y'),
412 KconfigCheck('self_protection', 'kspp', 'GCC_PLUGIN_STRUCTLEAK_BYREF_ALL', 'y'))]
413 l += [OR(KconfigCheck('self_protection', 'kspp', 'INIT_ON_FREE_DEFAULT_ON', 'y'),
414 KconfigCheck('self_protection', 'kspp', 'PAGE_POISONING_ZERO', 'y'))]
415 # CONFIG_INIT_ON_FREE_DEFAULT_ON was added in v5.3.
416 # CONFIG_PAGE_POISONING_ZERO was removed in v5.11.
417 # Starting from v5.11 CONFIG_PAGE_POISONING unconditionally checks
418 # the 0xAA poison pattern on allocation.
419 # That brings higher performance penalty.
420 if arch in ('X86_64', 'ARM64', 'X86_32'):
421 stackleak_is_set = KconfigCheck('self_protection', 'kspp', 'GCC_PLUGIN_STACKLEAK', 'y')
422 l += [stackleak_is_set]
423 l += [KconfigCheck('self_protection', 'kspp', 'RANDOMIZE_KSTACK_OFFSET_DEFAULT', 'y')]
424 l += [KconfigCheck('self_protection', 'kspp', 'SCHED_CORE', 'y')]
425 if arch in ('X86_64', 'X86_32'):
426 l += [KconfigCheck('self_protection', 'kspp', 'DEFAULT_MMAP_MIN_ADDR', '65536')]
427 if arch in ('ARM64', 'ARM'):
428 l += [KconfigCheck('self_protection', 'kspp', 'DEFAULT_MMAP_MIN_ADDR', '32768')]
429 l += [KconfigCheck('self_protection', 'kspp', 'SYN_COOKIES', 'y')] # another reason?
431 l += [KconfigCheck('self_protection', 'kspp', 'ARM64_SW_TTBR0_PAN', 'y')]
433 l += [KconfigCheck('self_protection', 'kspp', 'PAGE_TABLE_ISOLATION', 'y')]
434 l += [KconfigCheck('self_protection', 'kspp', 'HIGHMEM64G', 'y')]
435 l += [KconfigCheck('self_protection', 'kspp', 'X86_PAE', 'y')]
437 # 'self_protection', 'maintainer'
438 ubsan_bounds_is_set = KconfigCheck('self_protection', 'maintainer', 'UBSAN_BOUNDS', 'y') # only array index bounds checking
439 l += [ubsan_bounds_is_set] # recommended by Kees Cook in /issues/53
440 if arch in ('X86_64', 'ARM64', 'X86_32'): # ARCH_HAS_UBSAN_SANITIZE_ALL is not enabled for ARM
441 l += [AND(KconfigCheck('self_protection', 'maintainer', 'UBSAN_SANITIZE_ALL', 'y'),
442 ubsan_bounds_is_set)] # recommended by Kees Cook in /issues/53
443 l += [AND(KconfigCheck('self_protection', 'maintainer', 'UBSAN_TRAP', 'y'),
444 ubsan_bounds_is_set)] # recommended by Kees Cook in /issues/53
446 # 'self_protection', 'clipos'
447 l += [KconfigCheck('self_protection', 'clipos', 'DEBUG_VIRTUAL', 'y')]
448 l += [KconfigCheck('self_protection', 'clipos', 'STATIC_USERMODEHELPER', 'y')] # needs userspace support
449 l += [OR(KconfigCheck('self_protection', 'clipos', 'EFI_DISABLE_PCI_DMA', 'y'),
451 l += [KconfigCheck('self_protection', 'clipos', 'SLAB_MERGE_DEFAULT', 'is not set')] # slab_nomerge
452 l += [KconfigCheck('self_protection', 'clipos', 'RANDOM_TRUST_BOOTLOADER', 'is not set')]
453 l += [KconfigCheck('self_protection', 'clipos', 'RANDOM_TRUST_CPU', 'is not set')]
454 l += [AND(KconfigCheck('self_protection', 'clipos', 'GCC_PLUGIN_RANDSTRUCT_PERFORMANCE', 'is not set'),
456 if arch in ('X86_64', 'ARM64', 'X86_32'):
457 l += [AND(KconfigCheck('self_protection', 'clipos', 'STACKLEAK_METRICS', 'is not set'),
459 l += [AND(KconfigCheck('self_protection', 'clipos', 'STACKLEAK_RUNTIME_DISABLE', 'is not set'),
461 if arch in ('X86_64', 'X86_32'):
462 l += [AND(KconfigCheck('self_protection', 'clipos', 'INTEL_IOMMU_DEFAULT_ON', 'y'),
463 iommu_support_is_set)]
465 l += [AND(KconfigCheck('self_protection', 'clipos', 'INTEL_IOMMU_SVM', 'y'),
466 iommu_support_is_set)]
468 l += [AND(KconfigCheck('self_protection', 'clipos', 'INTEL_IOMMU', 'y'),
469 iommu_support_is_set)]
471 # 'self_protection', 'my'
472 l += [OR(KconfigCheck('self_protection', 'my', 'RESET_ATTACK_MITIGATION', 'y'),
473 efi_not_set)] # needs userspace support (systemd)
475 l += [KconfigCheck('self_protection', 'my', 'SLS', 'y')] # vs CVE-2021-26341 in Straight-Line-Speculation
476 l += [AND(KconfigCheck('self_protection', 'my', 'AMD_IOMMU_V2', 'y'),
477 iommu_support_is_set)]
479 l += [KconfigCheck('self_protection', 'my', 'SHADOW_CALL_STACK', 'y')] # depends on clang, maybe it's alternative to STACKPROTECTOR_STRONG
480 l += [KconfigCheck('self_protection', 'my', 'KASAN_HW_TAGS', 'y')]
481 cfi_clang_is_set = KconfigCheck('self_protection', 'my', 'CFI_CLANG', 'y')
482 l += [cfi_clang_is_set]
483 l += [AND(KconfigCheck('self_protection', 'my', 'CFI_PERMISSIVE', 'is not set'),
487 if arch in ('X86_64', 'ARM64', 'X86_32'):
488 l += [KconfigCheck('security_policy', 'defconfig', 'SECURITY', 'y')] # and choose your favourite LSM
490 l += [KconfigCheck('security_policy', 'kspp', 'SECURITY', 'y')] # and choose your favourite LSM
491 l += [KconfigCheck('security_policy', 'kspp', 'SECURITY_YAMA', 'y')]
492 l += [OR(KconfigCheck('security_policy', 'my', 'SECURITY_WRITABLE_HOOKS', 'is not set'),
493 KconfigCheck('security_policy', 'kspp', 'SECURITY_SELINUX_DISABLE', 'is not set'))]
494 l += [KconfigCheck('security_policy', 'clipos', 'SECURITY_LOCKDOWN_LSM', 'y')]
495 l += [KconfigCheck('security_policy', 'clipos', 'SECURITY_LOCKDOWN_LSM_EARLY', 'y')]
496 l += [KconfigCheck('security_policy', 'clipos', 'LOCK_DOWN_KERNEL_FORCE_CONFIDENTIALITY', 'y')]
497 l += [KconfigCheck('security_policy', 'my', 'SECURITY_SAFESETID', 'y')]
498 loadpin_is_set = KconfigCheck('security_policy', 'my', 'SECURITY_LOADPIN', 'y')
499 l += [loadpin_is_set] # needs userspace support
500 l += [AND(KconfigCheck('security_policy', 'my', 'SECURITY_LOADPIN_ENFORCE', 'y'),
503 # 'cut_attack_surface', 'defconfig'
504 l += [OR(KconfigCheck('cut_attack_surface', 'defconfig', 'BPF_UNPRIV_DEFAULT_OFF', 'y'),
505 bpf_syscall_not_set)] # see unprivileged_bpf_disabled
506 l += [KconfigCheck('cut_attack_surface', 'defconfig', 'SECCOMP', 'y')]
507 l += [KconfigCheck('cut_attack_surface', 'defconfig', 'SECCOMP_FILTER', 'y')]
508 if arch in ('X86_64', 'ARM64', 'X86_32'):
509 l += [OR(KconfigCheck('cut_attack_surface', 'defconfig', 'STRICT_DEVMEM', 'y'),
510 devmem_not_set)] # refers to LOCKDOWN
512 # 'cut_attack_surface', 'kspp'
513 l += [KconfigCheck('cut_attack_surface', 'kspp', 'ACPI_CUSTOM_METHOD', 'is not set')] # refers to LOCKDOWN
514 l += [KconfigCheck('cut_attack_surface', 'kspp', 'COMPAT_BRK', 'is not set')]
515 l += [KconfigCheck('cut_attack_surface', 'kspp', 'DEVKMEM', 'is not set')] # refers to LOCKDOWN
516 l += [KconfigCheck('cut_attack_surface', 'kspp', 'COMPAT_VDSO', 'is not set')]
517 l += [KconfigCheck('cut_attack_surface', 'kspp', 'BINFMT_MISC', 'is not set')]
518 l += [KconfigCheck('cut_attack_surface', 'kspp', 'INET_DIAG', 'is not set')]
519 l += [KconfigCheck('cut_attack_surface', 'kspp', 'KEXEC', 'is not set')] # refers to LOCKDOWN
520 l += [KconfigCheck('cut_attack_surface', 'kspp', 'PROC_KCORE', 'is not set')] # refers to LOCKDOWN
521 l += [KconfigCheck('cut_attack_surface', 'kspp', 'LEGACY_PTYS', 'is not set')]
522 l += [KconfigCheck('cut_attack_surface', 'kspp', 'HIBERNATION', 'is not set')] # refers to LOCKDOWN
523 l += [KconfigCheck('cut_attack_surface', 'kspp', 'IA32_EMULATION', 'is not set')]
524 l += [KconfigCheck('cut_attack_surface', 'kspp', 'X86_X32', 'is not set')]
525 l += [KconfigCheck('cut_attack_surface', 'kspp', 'MODIFY_LDT_SYSCALL', 'is not set')]
526 l += [KconfigCheck('cut_attack_surface', 'kspp', 'OABI_COMPAT', 'is not set')]
527 l += [modules_not_set]
528 l += [devmem_not_set]
529 l += [OR(KconfigCheck('cut_attack_surface', 'kspp', 'IO_STRICT_DEVMEM', 'y'),
530 devmem_not_set)] # refers to LOCKDOWN
532 l += [OR(KconfigCheck('cut_attack_surface', 'kspp', 'STRICT_DEVMEM', 'y'),
533 devmem_not_set)] # refers to LOCKDOWN
535 l += [KconfigCheck('cut_attack_surface', 'kspp', 'LEGACY_VSYSCALL_NONE', 'y')] # 'vsyscall=none'
537 # 'cut_attack_surface', 'grsec'
538 l += [KconfigCheck('cut_attack_surface', 'grsec', 'ZSMALLOC_STAT', 'is not set')]
539 l += [KconfigCheck('cut_attack_surface', 'grsec', 'PAGE_OWNER', 'is not set')]
540 l += [KconfigCheck('cut_attack_surface', 'grsec', 'DEBUG_KMEMLEAK', 'is not set')]
541 l += [KconfigCheck('cut_attack_surface', 'grsec', 'BINFMT_AOUT', 'is not set')]
542 l += [KconfigCheck('cut_attack_surface', 'grsec', 'KPROBE_EVENTS', 'is not set')]
543 l += [KconfigCheck('cut_attack_surface', 'grsec', 'UPROBE_EVENTS', 'is not set')]
544 l += [KconfigCheck('cut_attack_surface', 'grsec', 'GENERIC_TRACER', 'is not set')] # refers to LOCKDOWN
545 l += [KconfigCheck('cut_attack_surface', 'grsec', 'FUNCTION_TRACER', 'is not set')]
546 l += [KconfigCheck('cut_attack_surface', 'grsec', 'STACK_TRACER', 'is not set')]
547 l += [KconfigCheck('cut_attack_surface', 'grsec', 'HIST_TRIGGERS', 'is not set')]
548 l += [KconfigCheck('cut_attack_surface', 'grsec', 'BLK_DEV_IO_TRACE', 'is not set')]
549 l += [KconfigCheck('cut_attack_surface', 'grsec', 'PROC_VMCORE', 'is not set')]
550 l += [KconfigCheck('cut_attack_surface', 'grsec', 'PROC_PAGE_MONITOR', 'is not set')]
551 l += [KconfigCheck('cut_attack_surface', 'grsec', 'USELIB', 'is not set')]
552 l += [KconfigCheck('cut_attack_surface', 'grsec', 'CHECKPOINT_RESTORE', 'is not set')]
553 l += [KconfigCheck('cut_attack_surface', 'grsec', 'USERFAULTFD', 'is not set')]
554 l += [KconfigCheck('cut_attack_surface', 'grsec', 'HWPOISON_INJECT', 'is not set')]
555 l += [KconfigCheck('cut_attack_surface', 'grsec', 'MEM_SOFT_DIRTY', 'is not set')]
556 l += [KconfigCheck('cut_attack_surface', 'grsec', 'DEVPORT', 'is not set')] # refers to LOCKDOWN
557 l += [KconfigCheck('cut_attack_surface', 'grsec', 'DEBUG_FS', 'is not set')] # refers to LOCKDOWN
558 l += [KconfigCheck('cut_attack_surface', 'grsec', 'NOTIFIER_ERROR_INJECTION', 'is not set')]
559 l += [KconfigCheck('cut_attack_surface', 'grsec', 'FAIL_FUTEX', 'is not set')]
560 l += [KconfigCheck('cut_attack_surface', 'grsec', 'PUNIT_ATOM_DEBUG', 'is not set')]
561 l += [KconfigCheck('cut_attack_surface', 'grsec', 'ACPI_CONFIGFS', 'is not set')]
562 l += [KconfigCheck('cut_attack_surface', 'grsec', 'EDAC_DEBUG', 'is not set')]
563 l += [KconfigCheck('cut_attack_surface', 'grsec', 'DRM_I915_DEBUG', 'is not set')]
564 l += [KconfigCheck('cut_attack_surface', 'grsec', 'BCACHE_CLOSURES_DEBUG', 'is not set')]
565 l += [KconfigCheck('cut_attack_surface', 'grsec', 'DVB_C8SECTPFE', 'is not set')]
566 l += [KconfigCheck('cut_attack_surface', 'grsec', 'MTD_SLRAM', 'is not set')]
567 l += [KconfigCheck('cut_attack_surface', 'grsec', 'MTD_PHRAM', 'is not set')]
568 l += [KconfigCheck('cut_attack_surface', 'grsec', 'IO_URING', 'is not set')]
569 l += [KconfigCheck('cut_attack_surface', 'grsec', 'KCMP', 'is not set')]
570 l += [KconfigCheck('cut_attack_surface', 'grsec', 'RSEQ', 'is not set')]
571 l += [KconfigCheck('cut_attack_surface', 'grsec', 'LATENCYTOP', 'is not set')]
572 l += [KconfigCheck('cut_attack_surface', 'grsec', 'KCOV', 'is not set')]
573 l += [KconfigCheck('cut_attack_surface', 'grsec', 'PROVIDE_OHCI1394_DMA_INIT', 'is not set')]
574 l += [KconfigCheck('cut_attack_surface', 'grsec', 'SUNRPC_DEBUG', 'is not set')]
575 l += [AND(KconfigCheck('cut_attack_surface', 'grsec', 'PTDUMP_DEBUGFS', 'is not set'),
576 KconfigCheck('cut_attack_surface', 'grsec', 'X86_PTDUMP', 'is not set'))]
578 # 'cut_attack_surface', 'maintainer'
579 l += [KconfigCheck('cut_attack_surface', 'maintainer', 'DRM_LEGACY', 'is not set')] # recommended by Daniel Vetter in /issues/38
580 l += [KconfigCheck('cut_attack_surface', 'maintainer', 'FB', 'is not set')] # recommended by Daniel Vetter in /issues/38
581 l += [KconfigCheck('cut_attack_surface', 'maintainer', 'VT', 'is not set')] # recommended by Daniel Vetter in /issues/38
582 l += [KconfigCheck('cut_attack_surface', 'maintainer', 'BLK_DEV_FD', 'is not set')] # recommended by Denis Efremov in /pull/54
584 # 'cut_attack_surface', 'grapheneos'
585 l += [KconfigCheck('cut_attack_surface', 'grapheneos', 'AIO', 'is not set')]
587 # 'cut_attack_surface', 'clipos'
588 l += [KconfigCheck('cut_attack_surface', 'clipos', 'STAGING', 'is not set')]
589 l += [KconfigCheck('cut_attack_surface', 'clipos', 'KSM', 'is not set')] # to prevent FLUSH+RELOAD attack
590 # l += [KconfigCheck('cut_attack_surface', 'clipos', 'IKCONFIG', 'is not set')] # no, IKCONFIG is needed for this check :)
591 l += [KconfigCheck('cut_attack_surface', 'clipos', 'KALLSYMS', 'is not set')]
592 l += [KconfigCheck('cut_attack_surface', 'clipos', 'X86_VSYSCALL_EMULATION', 'is not set')]
593 l += [KconfigCheck('cut_attack_surface', 'clipos', 'MAGIC_SYSRQ', 'is not set')]
594 l += [KconfigCheck('cut_attack_surface', 'clipos', 'KEXEC_FILE', 'is not set')] # refers to LOCKDOWN (permissive)
595 l += [KconfigCheck('cut_attack_surface', 'clipos', 'USER_NS', 'is not set')] # user.max_user_namespaces=0
596 l += [KconfigCheck('cut_attack_surface', 'clipos', 'X86_MSR', 'is not set')] # refers to LOCKDOWN
597 l += [KconfigCheck('cut_attack_surface', 'clipos', 'X86_CPUID', 'is not set')]
598 l += [KconfigCheck('cut_attack_surface', 'clipos', 'X86_IOPL_IOPERM', 'is not set')] # refers to LOCKDOWN
599 l += [KconfigCheck('cut_attack_surface', 'clipos', 'ACPI_TABLE_UPGRADE', 'is not set')] # refers to LOCKDOWN
600 l += [KconfigCheck('cut_attack_surface', 'clipos', 'EFI_CUSTOM_SSDT_OVERLAYS', 'is not set')]
601 l += [AND(KconfigCheck('cut_attack_surface', 'clipos', 'LDISC_AUTOLOAD', 'is not set'),
602 PresenceCheck('LDISC_AUTOLOAD', 'kconfig'))]
603 if arch in ('X86_64', 'X86_32'):
604 l += [KconfigCheck('cut_attack_surface', 'clipos', 'X86_INTEL_TSX_MODE_OFF', 'y')] # tsx=off
606 # 'cut_attack_surface', 'lockdown'
607 l += [bpf_syscall_not_set] # refers to LOCKDOWN
608 l += [KconfigCheck('cut_attack_surface', 'lockdown', 'EFI_TEST', 'is not set')] # refers to LOCKDOWN
609 l += [KconfigCheck('cut_attack_surface', 'lockdown', 'MMIOTRACE_TEST', 'is not set')] # refers to LOCKDOWN
610 l += [KconfigCheck('cut_attack_surface', 'lockdown', 'KPROBES', 'is not set')] # refers to LOCKDOWN
612 # 'cut_attack_surface', 'my'
613 l += [OR(KconfigCheck('cut_attack_surface', 'my', 'TRIM_UNUSED_KSYMS', 'y'),
615 l += [KconfigCheck('cut_attack_surface', 'my', 'MMIOTRACE', 'is not set')] # refers to LOCKDOWN (permissive)
616 l += [KconfigCheck('cut_attack_surface', 'my', 'LIVEPATCH', 'is not set')]
617 l += [KconfigCheck('cut_attack_surface', 'my', 'IP_DCCP', 'is not set')]
618 l += [KconfigCheck('cut_attack_surface', 'my', 'IP_SCTP', 'is not set')]
619 l += [KconfigCheck('cut_attack_surface', 'my', 'FTRACE', 'is not set')] # refers to LOCKDOWN
620 l += [KconfigCheck('cut_attack_surface', 'my', 'VIDEO_VIVID', 'is not set')]
621 l += [KconfigCheck('cut_attack_surface', 'my', 'INPUT_EVBUG', 'is not set')] # Can be used as a keylogger
624 if arch in ('X86_64', 'ARM64', 'X86_32'):
625 l += [KconfigCheck('harden_userspace', 'defconfig', 'INTEGRITY', 'y')]
627 l += [KconfigCheck('harden_userspace', 'my', 'INTEGRITY', 'y')]
629 l += [KconfigCheck('harden_userspace', 'defconfig', 'ARM64_MTE', 'y')]
630 if arch in ('ARM', 'X86_32'):
631 l += [KconfigCheck('harden_userspace', 'defconfig', 'VMSPLIT_3G', 'y')]
632 if arch in ('X86_64', 'ARM64'):
633 l += [KconfigCheck('harden_userspace', 'clipos', 'ARCH_MMAP_RND_BITS', '32')]
634 if arch in ('X86_32', 'ARM'):
635 l += [KconfigCheck('harden_userspace', 'my', 'ARCH_MMAP_RND_BITS', '16')]
637 # l += [KconfigCheck('feature_test', 'my', 'LKDTM', 'm')] # only for debugging!
640 def print_unknown_options(checklist, parsed_options):
644 if o1.type != 'complex':
645 known_options.append(o1.name)
648 if o2.type != 'complex':
649 if hasattr(o2, 'name'):
650 known_options.append(o2.name)
653 if o3.type == 'complex':
654 sys.exit('[!] ERROR: unexpected ComplexOptCheck inside {}'.format(o2.name))
655 if hasattr(o3, 'name'):
656 known_options.append(o3.name)
658 for option, value in parsed_options.items():
659 if option not in known_options:
660 print('[?] No check for option {} ({})'.format(option, value))
663 def print_checklist(mode, checklist, with_results):
667 output.append(o.json_dump(with_results))
668 print(json.dumps(output))
675 print('=' * sep_line_len)
676 print('{:^40}|{:^7}|{:^12}|{:^10}|{:^18}'.format('option name', 'type', 'desired val', 'decision', 'reason'), end='')
678 print('| {}'.format('check result'), end='')
680 print('=' * sep_line_len)
683 for opt in checklist:
685 if mode == 'show_ok':
686 if not opt.result.startswith('OK'):
688 if mode == 'show_fail':
689 if not opt.result.startswith('FAIL'):
691 opt.table_print(mode, with_results)
693 if mode == 'verbose':
694 print('-' * sep_line_len)
699 fail_count = len(list(filter(lambda opt: opt.result.startswith('FAIL'), checklist)))
701 ok_count = len(list(filter(lambda opt: opt.result.startswith('OK'), checklist)))
703 if mode == 'show_ok':
704 fail_suppressed = ' (suppressed in output)'
705 if mode == 'show_fail':
706 ok_suppressed = ' (suppressed in output)'
708 print('[+] Config check is finished: \'OK\' - {}{} / \'FAIL\' - {}{}'.format(ok_count, ok_suppressed, fail_count, fail_suppressed))
711 def populate_simple_opt_with_data(opt, data, data_type):
712 if opt.type == 'complex':
713 sys.exit('[!] ERROR: unexpected ComplexOptCheck {}: {}'.format(opt.name, vars(opt)))
714 if data_type not in TYPES_OF_CHECKS:
715 sys.exit('[!] ERROR: invalid data type "{}"'.format(data_type))
717 if data_type != opt.type:
720 if data_type == 'kconfig':
721 opt.state = data.get(opt.name, None)
722 elif data_type == 'version':
726 def populate_opt_with_data(opt, data, data_type):
727 if opt.type == 'complex':
729 if o.type == 'complex':
730 # Recursion for nested ComplexOptCheck objects
731 populate_opt_with_data(o, data, data_type)
733 populate_simple_opt_with_data(o, data, data_type)
735 if opt.type != 'kconfig':
736 sys.exit('[!] ERROR: bad type "{}" for a simple check {}'.format(opt.type, opt.name))
737 populate_simple_opt_with_data(opt, data, data_type)
740 def populate_with_data(checklist, data, data_type):
741 for opt in checklist:
742 populate_opt_with_data(opt, data, data_type)
745 def perform_checks(checklist):
746 for opt in checklist:
750 def parse_kconfig_file(parsed_options, fname):
751 with open(fname, 'r') as f:
752 opt_is_on = re.compile("CONFIG_[a-zA-Z0-9_]*=[a-zA-Z0-9_\"]*")
753 opt_is_off = re.compile("# CONFIG_[a-zA-Z0-9_]* is not set")
755 for line in f.readlines():
760 if opt_is_on.match(line):
761 option, value = line.split('=', 1)
762 elif opt_is_off.match(line):
763 option, value = line[2:].split(' ', 1)
764 if value != 'is not set':
765 sys.exit('[!] ERROR: bad disabled kconfig option "{}"'.format(line))
767 if option in parsed_options:
768 sys.exit('[!] ERROR: kconfig option "{}" exists multiple times'.format(line))
771 parsed_options[option] = value
777 # - reporting about unknown kernel options in the kconfig
778 # - verbose printing of ComplexOptCheck items
779 # * json mode for printing the results in JSON format
780 report_modes = ['verbose', 'json', 'show_ok', 'show_fail']
781 supported_archs = ['X86_64', 'X86_32', 'ARM64', 'ARM']
782 parser = ArgumentParser(prog='kconfig-hardened-check',
783 description='A tool for checking the security hardening options of the Linux kernel')
784 parser.add_argument('--version', action='version', version='%(prog)s ' + __version__)
785 parser.add_argument('-p', '--print', choices=supported_archs,
786 help='print security hardening preferences for the selected architecture')
787 parser.add_argument('-c', '--config',
788 help='check the kernel kconfig file against these preferences')
789 parser.add_argument('-m', '--mode', choices=report_modes,
790 help='choose the report mode')
791 args = parser.parse_args()
797 print('[+] Special report mode: {}'.format(mode))
799 config_checklist = []
803 print('[+] Kconfig file to check: {}'.format(args.config))
805 arch, msg = detect_arch(args.config, supported_archs)
807 sys.exit('[!] ERROR: {}'.format(msg))
809 print('[+] Detected architecture: {}'.format(arch))
811 kernel_version, msg = detect_version(args.config)
812 if not kernel_version:
813 sys.exit('[!] ERROR: {}'.format(msg))
815 print('[+] Detected kernel version: {}.{}'.format(kernel_version[0], kernel_version[1]))
817 # add relevant kconfig checks to the checklist
818 add_kconfig_checks(config_checklist, arch)
820 # populate the checklist with the parsed kconfig data
821 parsed_kconfig_options = OrderedDict()
822 parse_kconfig_file(parsed_kconfig_options, args.config)
823 populate_with_data(config_checklist, parsed_kconfig_options, 'kconfig')
824 populate_with_data(config_checklist, kernel_version, 'version')
826 # now everything is ready for performing the checks
827 perform_checks(config_checklist)
829 # finally print the results
830 if mode == 'verbose':
831 print_unknown_options(config_checklist, parsed_kconfig_options)
832 print_checklist(mode, config_checklist, True)
837 if mode in ('show_ok', 'show_fail'):
838 sys.exit('[!] ERROR: wrong mode "{}" for --print'.format(mode))
840 add_kconfig_checks(config_checklist, arch)
842 print('[+] Printing kernel security hardening preferences for {}...'.format(arch))
843 print_checklist(mode, config_checklist, False)
849 if __name__ == '__main__':