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?)
17 # slub_debug=FZ (slow)
18 # init_on_alloc=1 (since v5.3)
19 # init_on_free=1 (since v5.3, otherwise slub_debug=P and page_poison=1)
21 # debugfs=no-mount (or off if possible)
22 # randomize_kstack_offset=1
24 # Mitigations of CPU vulnerabilities:
26 # mitigations=auto,nosmt (nosmt is slow)
30 # spec_store_bypass_disable=on
44 # Hardware tag-based KASAN with arm64 Memory Tagging Extension (MTE):
46 # kasan.stacktrace=off
49 # N.B. Hardening sysctls:
50 # kernel.kptr_restrict=2 (or 1?)
51 # kernel.dmesg_restrict=1 (also see the kconfig option)
52 # kernel.perf_event_paranoid=3
53 # kernel.kexec_load_disabled=1
54 # kernel.yama.ptrace_scope=3
55 # user.max_user_namespaces=0
56 # what about bpf_jit_enable?
57 # kernel.unprivileged_bpf_disabled=1
58 # net.core.bpf_jit_harden=2
60 # vm.unprivileged_userfaultfd=0
61 # (at first, it disabled unprivileged userfaultfd,
62 # and since v5.11 it enables unprivileged userfaultfd for user-mode only)
64 # dev.tty.ldisc_autoload=0
65 # fs.protected_symlinks=1
66 # fs.protected_hardlinks=1
67 # fs.protected_fifos=2
68 # fs.protected_regular=2
70 # kernel.modules_disabled=1
73 # pylint: disable=missing-module-docstring,missing-class-docstring,missing-function-docstring
74 # pylint: disable=line-too-long,invalid-name,too-many-branches,too-many-statements
78 from argparse import ArgumentParser
79 from collections import OrderedDict
82 from .__about__ import __version__
86 def __init__(self, reason, decision, name, expected):
88 self.expected = expected
89 self.decision = decision
95 if self.expected == self.state:
97 elif self.state is None:
98 if self.expected == 'is not set':
99 self.result = 'OK: not found'
101 self.result = 'FAIL: not found'
103 self.result = 'FAIL: "' + self.state + '"'
105 if self.result.startswith('OK'):
109 def table_print(self, _mode, with_results):
110 print('{:<40}|{:^7}|{:^12}|{:^10}|{:^18}'.format(self.name, self.type, self.expected, self.decision, self.reason), end='')
112 print('| {}'.format(self.result), end='')
115 class KconfigCheck(OptCheck):
116 def __init__(self, *args, **kwargs):
117 super().__init__(*args, **kwargs)
118 self.name = 'CONFIG_' + self.name
126 def __init__(self, ver_expected):
127 self.ver_expected = ver_expected
132 if self.ver[0] > self.ver_expected[0]:
133 self.result = 'OK: version >= ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
135 if self.ver[0] < self.ver_expected[0]:
136 self.result = 'FAIL: version < ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
138 if self.ver[1] >= self.ver_expected[1]:
139 self.result = 'OK: version >= ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
141 self.result = 'FAIL: version < ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
144 def table_print(self, _mode, with_results):
145 ver_req = 'kernel version >= ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
146 print('{:<91}'.format(ver_req), end='')
148 print('| {}'.format(self.result), end='')
152 def __init__(self, name, type):
153 if type == 'kconfig':
154 self.name = 'CONFIG_' + name
161 if self.state is None:
162 self.result = 'FAIL: not present'
164 self.result = 'OK: is present'
167 def table_print(self, _mode, with_results):
168 print('{:<91}'.format(self.name + ' is present'), end='')
170 print('| {}'.format(self.result), end='')
173 class ComplexOptCheck:
174 def __init__(self, *opts):
177 sys.exit('[!] ERROR: empty {} check'.format(self.__class__.__name__))
178 if not isinstance(opts[0], KconfigCheck):
179 sys.exit('[!] ERROR: invalid {} check: {}'.format(self.__class__.__name__, opts))
184 return self.opts[0].name
188 return self.opts[0].type
192 return self.opts[0].expected
196 return self.opts[0].decision
200 return self.opts[0].reason
202 def table_print(self, mode, with_results):
203 if mode == 'verbose':
204 print(' {:87}'.format('<<< ' + self.__class__.__name__ + ' >>>'), end='')
206 print('| {}'.format(self.result), end='')
209 o.table_print(mode, with_results)
212 o.table_print(mode, False)
214 print('| {}'.format(self.result), end='')
217 class OR(ComplexOptCheck):
218 # self.opts[0] is the option that this OR-check is about.
220 # OR(<X_is_hardened>, <X_is_disabled>)
221 # OR(<X_is_hardened>, <old_X_is_hardened>)
225 sys.exit('[!] ERROR: invalid OR check')
227 for i, opt in enumerate(self.opts):
230 if opt.result == 'OK' and i != 0:
231 # Simple OK is not enough for additional checks, add more info:
232 self.result = 'OK: {} "{}"'.format(opt.name, opt.expected)
234 self.result = opt.result
236 self.result = self.opts[0].result
240 class AND(ComplexOptCheck):
241 # self.opts[0] is the option that this AND-check is about.
243 # AND(<suboption>, <main_option>)
244 # Suboption is not checked if checking of the main_option is failed.
245 # AND(<X_is_disabled>, <old_X_is_disabled>)
248 for i, opt in reversed(list(enumerate(self.opts))):
251 self.result = opt.result
254 # This FAIL is caused by additional checks,
255 # and not by the main option that this AND-check is about.
256 # Describe the reason of the FAIL.
257 if opt.result.startswith('FAIL: \"') or opt.result == 'FAIL: not found':
258 self.result = 'FAIL: {} not "{}"'.format(opt.name, opt.expected)
259 elif opt.result == 'FAIL: not present':
260 self.result = 'FAIL: {} not present'.format(opt.name)
262 # This FAIL message is self-explaining.
263 self.result = opt.result
266 sys.exit('[!] ERROR: invalid AND check')
269 def detect_arch(fname, archs):
270 with open(fname, 'r') as f:
271 arch_pattern = re.compile("CONFIG_[a-zA-Z0-9_]*=y")
273 for line in f.readlines():
274 if arch_pattern.match(line):
275 option, _ = line[7:].split('=', 1)
280 return None, 'more than one supported architecture is detected'
282 return None, 'failed to detect architecture'
286 def detect_version(fname):
287 with open(fname, 'r') as f:
288 ver_pattern = re.compile("# Linux/.* Kernel Configuration")
289 for line in f.readlines():
290 if ver_pattern.match(line):
294 ver_numbers = ver_str.split('.')
295 if len(ver_numbers) < 3 or not ver_numbers[0].isdigit() or not ver_numbers[1].isdigit():
296 msg = 'failed to parse the version "' + ver_str + '"'
298 return (int(ver_numbers[0]), int(ver_numbers[1])), None
299 return None, 'no kernel version detected'
302 def add_kconfig_checks(l, arch):
303 # Calling the KconfigCheck class constructor:
304 # KconfigCheck(reason, decision, name, expected)
306 modules_not_set = KconfigCheck('cut_attack_surface', 'kspp', 'MODULES', 'is not set')
307 devmem_not_set = KconfigCheck('cut_attack_surface', 'kspp', 'DEVMEM', 'is not set') # refers to LOCKDOWN
309 # 'self_protection', 'defconfig'
310 l += [KconfigCheck('self_protection', 'defconfig', 'BUG', 'y')]
311 l += [KconfigCheck('self_protection', 'defconfig', 'SLUB_DEBUG', 'y')]
312 l += [KconfigCheck('self_protection', 'defconfig', 'GCC_PLUGINS', 'y')]
313 l += [OR(KconfigCheck('self_protection', 'defconfig', 'STACKPROTECTOR_STRONG', 'y'),
314 KconfigCheck('self_protection', 'defconfig', 'CC_STACKPROTECTOR_STRONG', 'y'))]
315 l += [OR(KconfigCheck('self_protection', 'defconfig', 'STRICT_KERNEL_RWX', 'y'),
316 KconfigCheck('self_protection', 'defconfig', 'DEBUG_RODATA', 'y'))] # before v4.11
317 l += [OR(KconfigCheck('self_protection', 'defconfig', 'STRICT_MODULE_RWX', 'y'),
318 KconfigCheck('self_protection', 'defconfig', 'DEBUG_SET_MODULE_RONX', 'y'),
319 modules_not_set)] # DEBUG_SET_MODULE_RONX was before v4.11
320 l += [OR(KconfigCheck('self_protection', 'defconfig', 'REFCOUNT_FULL', 'y'),
321 VerCheck((5, 5)))] # REFCOUNT_FULL is enabled by default since v5.5
322 iommu_support_is_set = KconfigCheck('self_protection', 'defconfig', 'IOMMU_SUPPORT', 'y')
323 l += [iommu_support_is_set] # is needed for mitigating DMA attacks
324 if arch in ('X86_64', 'ARM64', 'X86_32'):
325 l += [KconfigCheck('self_protection', 'defconfig', 'RANDOMIZE_BASE', 'y')]
326 l += [KconfigCheck('self_protection', 'defconfig', 'THREAD_INFO_IN_TASK', 'y')]
327 if arch in ('X86_64', 'ARM64'):
328 l += [KconfigCheck('self_protection', 'defconfig', 'VMAP_STACK', 'y')]
329 if arch in ('X86_64', 'X86_32'):
330 l += [KconfigCheck('self_protection', 'defconfig', 'MICROCODE', 'y')] # is needed for mitigating CPU bugs
331 l += [KconfigCheck('self_protection', 'defconfig', 'RETPOLINE', 'y')]
332 l += [KconfigCheck('self_protection', 'defconfig', 'X86_SMAP', 'y')]
333 l += [KconfigCheck('self_protection', 'defconfig', 'SYN_COOKIES', 'y')] # another reason?
334 l += [OR(KconfigCheck('self_protection', 'defconfig', 'X86_UMIP', 'y'),
335 KconfigCheck('self_protection', 'defconfig', 'X86_INTEL_UMIP', 'y'))]
336 if arch in ('ARM64', 'ARM'):
337 l += [KconfigCheck('self_protection', 'defconfig', 'STACKPROTECTOR_PER_TASK', 'y')]
339 l += [KconfigCheck('self_protection', 'defconfig', 'PAGE_TABLE_ISOLATION', 'y')]
340 l += [KconfigCheck('self_protection', 'defconfig', 'RANDOMIZE_MEMORY', 'y')]
341 l += [AND(KconfigCheck('self_protection', 'defconfig', 'INTEL_IOMMU', 'y'),
342 iommu_support_is_set)]
343 l += [AND(KconfigCheck('self_protection', 'defconfig', 'AMD_IOMMU', 'y'),
344 iommu_support_is_set)]
346 l += [KconfigCheck('self_protection', 'defconfig', 'ARM64_PAN', 'y')]
347 l += [KconfigCheck('self_protection', 'defconfig', 'ARM64_EPAN', 'y')]
348 l += [KconfigCheck('self_protection', 'defconfig', 'UNMAP_KERNEL_AT_EL0', 'y')]
349 l += [OR(KconfigCheck('self_protection', 'defconfig', 'HARDEN_EL2_VECTORS', 'y'),
350 AND(KconfigCheck('self_protection', 'defconfig', 'RANDOMIZE_BASE', 'y'),
351 VerCheck((5, 9))))] # HARDEN_EL2_VECTORS was included in RANDOMIZE_BASE in v5.9
352 l += [KconfigCheck('self_protection', 'defconfig', 'RODATA_FULL_DEFAULT_ENABLED', 'y')]
353 l += [KconfigCheck('self_protection', 'defconfig', 'ARM64_PTR_AUTH_KERNEL', 'y')]
354 l += [KconfigCheck('self_protection', 'defconfig', 'ARM64_BTI_KERNEL', 'y')]
355 l += [OR(KconfigCheck('self_protection', 'defconfig', 'HARDEN_BRANCH_PREDICTOR', 'y'),
356 VerCheck((5, 10)))] # HARDEN_BRANCH_PREDICTOR is enabled by default since v5.10
357 l += [KconfigCheck('self_protection', 'defconfig', 'ARM64_MTE', 'y')]
359 l += [KconfigCheck('self_protection', 'defconfig', 'CPU_SW_DOMAIN_PAN', 'y')]
360 l += [KconfigCheck('self_protection', 'defconfig', 'HARDEN_BRANCH_PREDICTOR', 'y')]
362 # 'self_protection', 'kspp'
363 l += [KconfigCheck('self_protection', 'kspp', 'SECURITY_DMESG_RESTRICT', 'y')]
364 l += [KconfigCheck('self_protection', 'kspp', 'BUG_ON_DATA_CORRUPTION', 'y')]
365 l += [KconfigCheck('self_protection', 'kspp', 'DEBUG_WX', 'y')]
366 l += [KconfigCheck('self_protection', 'kspp', 'SCHED_STACK_END_CHECK', 'y')]
367 l += [KconfigCheck('self_protection', 'kspp', 'SLAB_FREELIST_HARDENED', 'y')]
368 l += [KconfigCheck('self_protection', 'kspp', 'SLAB_FREELIST_RANDOM', 'y')]
369 l += [KconfigCheck('self_protection', 'kspp', 'SHUFFLE_PAGE_ALLOCATOR', 'y')]
370 l += [KconfigCheck('self_protection', 'kspp', 'FORTIFY_SOURCE', 'y')]
371 l += [KconfigCheck('self_protection', 'kspp', 'DEBUG_LIST', 'y')]
372 l += [KconfigCheck('self_protection', 'kspp', 'DEBUG_SG', 'y')]
373 l += [KconfigCheck('self_protection', 'kspp', 'DEBUG_CREDENTIALS', 'y')]
374 l += [KconfigCheck('self_protection', 'kspp', 'DEBUG_NOTIFIERS', 'y')]
375 l += [KconfigCheck('self_protection', 'kspp', 'INIT_ON_ALLOC_DEFAULT_ON', 'y')]
376 l += [KconfigCheck('self_protection', 'kspp', 'GCC_PLUGIN_LATENT_ENTROPY', 'y')]
377 randstruct_is_set = KconfigCheck('self_protection', 'kspp', 'GCC_PLUGIN_RANDSTRUCT', 'y')
378 l += [randstruct_is_set]
379 hardened_usercopy_is_set = KconfigCheck('self_protection', 'kspp', 'HARDENED_USERCOPY', 'y')
380 l += [hardened_usercopy_is_set]
381 l += [AND(KconfigCheck('self_protection', 'kspp', 'HARDENED_USERCOPY_FALLBACK', 'is not set'),
382 hardened_usercopy_is_set)]
383 l += [AND(KconfigCheck('self_protection', 'kspp', 'HARDENED_USERCOPY_PAGESPAN', 'is not set'),
384 hardened_usercopy_is_set)]
385 l += [OR(KconfigCheck('self_protection', 'kspp', 'MODULE_SIG', 'y'),
387 l += [OR(KconfigCheck('self_protection', 'kspp', 'MODULE_SIG_ALL', 'y'),
389 l += [OR(KconfigCheck('self_protection', 'kspp', 'MODULE_SIG_SHA512', 'y'),
391 l += [OR(KconfigCheck('self_protection', 'kspp', 'MODULE_SIG_FORCE', 'y'),
392 modules_not_set)] # refers to LOCKDOWN
393 l += [OR(KconfigCheck('self_protection', 'kspp', 'INIT_STACK_ALL_ZERO', 'y'),
394 KconfigCheck('self_protection', 'kspp', 'GCC_PLUGIN_STRUCTLEAK_BYREF_ALL', 'y'))]
395 l += [OR(KconfigCheck('self_protection', 'kspp', 'INIT_ON_FREE_DEFAULT_ON', 'y'),
396 KconfigCheck('self_protection', 'kspp', 'PAGE_POISONING_ZERO', 'y'))]
397 # CONFIG_INIT_ON_FREE_DEFAULT_ON was added in v5.3.
398 # CONFIG_PAGE_POISONING_ZERO was removed in v5.11.
399 # Starting from v5.11 CONFIG_PAGE_POISONING unconditionally checks
400 # the 0xAA poison pattern on allocation.
401 # That brings higher performance penalty.
402 if arch in ('X86_64', 'ARM64', 'X86_32'):
403 stackleak_is_set = KconfigCheck('self_protection', 'kspp', 'GCC_PLUGIN_STACKLEAK', 'y')
404 l += [stackleak_is_set]
405 l += [KconfigCheck('self_protection', 'kspp', 'RANDOMIZE_KSTACK_OFFSET_DEFAULT', 'y')]
406 if arch in ('X86_64', 'X86_32'):
407 l += [KconfigCheck('self_protection', 'kspp', 'DEFAULT_MMAP_MIN_ADDR', '65536')]
408 if arch in ('ARM64', 'ARM'):
409 l += [KconfigCheck('self_protection', 'kspp', 'DEFAULT_MMAP_MIN_ADDR', '32768')]
410 l += [KconfigCheck('self_protection', 'kspp', 'SYN_COOKIES', 'y')] # another reason?
412 l += [KconfigCheck('self_protection', 'kspp', 'ARM64_SW_TTBR0_PAN', 'y')]
414 l += [KconfigCheck('self_protection', 'kspp', 'PAGE_TABLE_ISOLATION', 'y')]
415 l += [KconfigCheck('self_protection', 'kspp', 'HIGHMEM64G', 'y')]
416 l += [KconfigCheck('self_protection', 'kspp', 'X86_PAE', 'y')]
418 # 'self_protection', 'maintainer'
419 ubsan_bounds_is_set = KconfigCheck('self_protection', 'maintainer', 'UBSAN_BOUNDS', 'y') # only array index bounds checking
420 l += [ubsan_bounds_is_set] # recommended by Kees Cook in /issues/53
421 l += [AND(KconfigCheck('self_protection', 'maintainer', 'UBSAN_SANITIZE_ALL', 'y'),
422 ubsan_bounds_is_set)] # recommended by Kees Cook in /issues/53
423 l += [AND(KconfigCheck('self_protection', 'maintainer', 'UBSAN_TRAP', 'y'),
424 ubsan_bounds_is_set)] # recommended by Kees Cook in /issues/53
426 # 'self_protection', 'clipos'
427 l += [KconfigCheck('self_protection', 'clipos', 'DEBUG_VIRTUAL', 'y')]
428 l += [KconfigCheck('self_protection', 'clipos', 'STATIC_USERMODEHELPER', 'y')] # needs userspace support
429 l += [KconfigCheck('self_protection', 'clipos', 'EFI_DISABLE_PCI_DMA', 'y')]
430 l += [KconfigCheck('self_protection', 'clipos', 'SLAB_MERGE_DEFAULT', 'is not set')] # slab_nomerge
431 l += [KconfigCheck('self_protection', 'clipos', 'RANDOM_TRUST_BOOTLOADER', 'is not set')]
432 l += [KconfigCheck('self_protection', 'clipos', 'RANDOM_TRUST_CPU', 'is not set')]
433 l += [AND(KconfigCheck('self_protection', 'clipos', 'GCC_PLUGIN_RANDSTRUCT_PERFORMANCE', 'is not set'),
435 if arch in ('X86_64', 'ARM64', 'X86_32'):
436 l += [AND(KconfigCheck('self_protection', 'clipos', 'STACKLEAK_METRICS', 'is not set'),
438 l += [AND(KconfigCheck('self_protection', 'clipos', 'STACKLEAK_RUNTIME_DISABLE', 'is not set'),
440 if arch in ('X86_64', 'X86_32'):
441 l += [AND(KconfigCheck('self_protection', 'clipos', 'INTEL_IOMMU_DEFAULT_ON', 'y'),
442 iommu_support_is_set)]
444 l += [AND(KconfigCheck('self_protection', 'clipos', 'INTEL_IOMMU_SVM', 'y'),
445 iommu_support_is_set)]
447 l += [AND(KconfigCheck('self_protection', 'clipos', 'INTEL_IOMMU', 'y'),
448 iommu_support_is_set)]
450 # 'self_protection', 'my'
451 l += [KconfigCheck('self_protection', 'my', 'RESET_ATTACK_MITIGATION', 'y')] # needs userspace support (systemd)
453 l += [AND(KconfigCheck('self_protection', 'my', 'AMD_IOMMU_V2', 'y'),
454 iommu_support_is_set)]
456 l += [KconfigCheck('self_protection', 'my', 'SHADOW_CALL_STACK', 'y')] # depends on clang, maybe it's alternative to STACKPROTECTOR_STRONG
457 l += [KconfigCheck('self_protection', 'my', 'KASAN_HW_TAGS', 'y')]
458 cfi_clang_is_set = KconfigCheck('self_protection', 'my', 'CFI_CLANG', 'y')
459 l += [cfi_clang_is_set]
460 l += [AND(KconfigCheck('self_protection', 'my', 'CFI_PERMISSIVE', 'is not set'),
464 if arch in ('X86_64', 'ARM64', 'X86_32'):
465 l += [KconfigCheck('security_policy', 'defconfig', 'SECURITY', 'y')] # and choose your favourite LSM
467 l += [KconfigCheck('security_policy', 'kspp', 'SECURITY', 'y')] # and choose your favourite LSM
468 l += [KconfigCheck('security_policy', 'kspp', 'SECURITY_YAMA', 'y')]
469 l += [OR(KconfigCheck('security_policy', 'my', 'SECURITY_WRITABLE_HOOKS', 'is not set'),
470 KconfigCheck('security_policy', 'kspp', 'SECURITY_SELINUX_DISABLE', 'is not set'))]
471 l += [KconfigCheck('security_policy', 'clipos', 'SECURITY_LOCKDOWN_LSM', 'y')]
472 l += [KconfigCheck('security_policy', 'clipos', 'SECURITY_LOCKDOWN_LSM_EARLY', 'y')]
473 l += [KconfigCheck('security_policy', 'clipos', 'LOCK_DOWN_KERNEL_FORCE_CONFIDENTIALITY', 'y')]
474 l += [KconfigCheck('security_policy', 'my', 'SECURITY_SAFESETID', 'y')]
475 loadpin_is_set = KconfigCheck('security_policy', 'my', 'SECURITY_LOADPIN', 'y')
476 l += [loadpin_is_set] # needs userspace support
477 l += [AND(KconfigCheck('security_policy', 'my', 'SECURITY_LOADPIN_ENFORCE', 'y'),
480 # 'cut_attack_surface', 'defconfig'
481 l += [KconfigCheck('cut_attack_surface', 'defconfig', 'SECCOMP', 'y')]
482 l += [KconfigCheck('cut_attack_surface', 'defconfig', 'SECCOMP_FILTER', 'y')]
483 if arch in ('X86_64', 'ARM64', 'X86_32'):
484 l += [OR(KconfigCheck('cut_attack_surface', 'defconfig', 'STRICT_DEVMEM', 'y'),
485 devmem_not_set)] # refers to LOCKDOWN
487 # 'cut_attack_surface', 'kspp'
488 l += [KconfigCheck('cut_attack_surface', 'kspp', 'ACPI_CUSTOM_METHOD', 'is not set')] # refers to LOCKDOWN
489 l += [KconfigCheck('cut_attack_surface', 'kspp', 'COMPAT_BRK', 'is not set')]
490 l += [KconfigCheck('cut_attack_surface', 'kspp', 'DEVKMEM', 'is not set')] # refers to LOCKDOWN
491 l += [KconfigCheck('cut_attack_surface', 'kspp', 'COMPAT_VDSO', 'is not set')]
492 l += [KconfigCheck('cut_attack_surface', 'kspp', 'BINFMT_MISC', 'is not set')]
493 l += [KconfigCheck('cut_attack_surface', 'kspp', 'INET_DIAG', 'is not set')]
494 l += [KconfigCheck('cut_attack_surface', 'kspp', 'KEXEC', 'is not set')] # refers to LOCKDOWN
495 l += [KconfigCheck('cut_attack_surface', 'kspp', 'PROC_KCORE', 'is not set')] # refers to LOCKDOWN
496 l += [KconfigCheck('cut_attack_surface', 'kspp', 'LEGACY_PTYS', 'is not set')]
497 l += [KconfigCheck('cut_attack_surface', 'kspp', 'HIBERNATION', 'is not set')] # refers to LOCKDOWN
498 l += [KconfigCheck('cut_attack_surface', 'kspp', 'IA32_EMULATION', 'is not set')]
499 l += [KconfigCheck('cut_attack_surface', 'kspp', 'X86_X32', 'is not set')]
500 l += [KconfigCheck('cut_attack_surface', 'kspp', 'MODIFY_LDT_SYSCALL', 'is not set')]
501 l += [KconfigCheck('cut_attack_surface', 'kspp', 'OABI_COMPAT', 'is not set')]
502 l += [modules_not_set]
503 l += [devmem_not_set]
504 l += [OR(KconfigCheck('cut_attack_surface', 'kspp', 'IO_STRICT_DEVMEM', 'y'),
505 devmem_not_set)] # refers to LOCKDOWN
507 l += [OR(KconfigCheck('cut_attack_surface', 'kspp', 'STRICT_DEVMEM', 'y'),
508 devmem_not_set)] # refers to LOCKDOWN
510 l += [KconfigCheck('cut_attack_surface', 'kspp', 'LEGACY_VSYSCALL_NONE', 'y')] # 'vsyscall=none'
512 # 'cut_attack_surface', 'grsec'
513 l += [KconfigCheck('cut_attack_surface', 'grsec', 'ZSMALLOC_STAT', 'is not set')]
514 l += [KconfigCheck('cut_attack_surface', 'grsec', 'PAGE_OWNER', 'is not set')]
515 l += [KconfigCheck('cut_attack_surface', 'grsec', 'DEBUG_KMEMLEAK', 'is not set')]
516 l += [KconfigCheck('cut_attack_surface', 'grsec', 'BINFMT_AOUT', 'is not set')]
517 l += [KconfigCheck('cut_attack_surface', 'grsec', 'KPROBE_EVENTS', 'is not set')]
518 l += [KconfigCheck('cut_attack_surface', 'grsec', 'UPROBE_EVENTS', 'is not set')]
519 l += [KconfigCheck('cut_attack_surface', 'grsec', 'GENERIC_TRACER', 'is not set')] # refers to LOCKDOWN
520 l += [KconfigCheck('cut_attack_surface', 'grsec', 'FUNCTION_TRACER', 'is not set')]
521 l += [KconfigCheck('cut_attack_surface', 'grsec', 'STACK_TRACER', 'is not set')]
522 l += [KconfigCheck('cut_attack_surface', 'grsec', 'HIST_TRIGGERS', 'is not set')]
523 l += [KconfigCheck('cut_attack_surface', 'grsec', 'BLK_DEV_IO_TRACE', 'is not set')]
524 l += [KconfigCheck('cut_attack_surface', 'grsec', 'PROC_VMCORE', 'is not set')]
525 l += [KconfigCheck('cut_attack_surface', 'grsec', 'PROC_PAGE_MONITOR', 'is not set')]
526 l += [KconfigCheck('cut_attack_surface', 'grsec', 'USELIB', 'is not set')]
527 l += [KconfigCheck('cut_attack_surface', 'grsec', 'CHECKPOINT_RESTORE', 'is not set')]
528 l += [KconfigCheck('cut_attack_surface', 'grsec', 'USERFAULTFD', 'is not set')]
529 l += [KconfigCheck('cut_attack_surface', 'grsec', 'HWPOISON_INJECT', 'is not set')]
530 l += [KconfigCheck('cut_attack_surface', 'grsec', 'MEM_SOFT_DIRTY', 'is not set')]
531 l += [KconfigCheck('cut_attack_surface', 'grsec', 'DEVPORT', 'is not set')] # refers to LOCKDOWN
532 l += [KconfigCheck('cut_attack_surface', 'grsec', 'DEBUG_FS', 'is not set')] # refers to LOCKDOWN
533 l += [KconfigCheck('cut_attack_surface', 'grsec', 'NOTIFIER_ERROR_INJECTION', 'is not set')]
534 l += [KconfigCheck('cut_attack_surface', 'grsec', 'FAIL_FUTEX', 'is not set')]
535 l += [KconfigCheck('cut_attack_surface', 'grsec', 'PUNIT_ATOM_DEBUG', 'is not set')]
536 l += [KconfigCheck('cut_attack_surface', 'grsec', 'ACPI_CONFIGFS', 'is not set')]
537 l += [KconfigCheck('cut_attack_surface', 'grsec', 'EDAC_DEBUG', 'is not set')]
538 l += [KconfigCheck('cut_attack_surface', 'grsec', 'DRM_I915_DEBUG', 'is not set')]
539 l += [KconfigCheck('cut_attack_surface', 'grsec', 'BCACHE_CLOSURES_DEBUG', 'is not set')]
540 l += [KconfigCheck('cut_attack_surface', 'grsec', 'DVB_C8SECTPFE', 'is not set')]
541 l += [KconfigCheck('cut_attack_surface', 'grsec', 'MTD_SLRAM', 'is not set')]
542 l += [KconfigCheck('cut_attack_surface', 'grsec', 'MTD_PHRAM', 'is not set')]
543 l += [KconfigCheck('cut_attack_surface', 'grsec', 'IO_URING', 'is not set')]
544 l += [KconfigCheck('cut_attack_surface', 'grsec', 'KCMP', 'is not set')]
545 l += [KconfigCheck('cut_attack_surface', 'grsec', 'RSEQ', 'is not set')]
546 l += [KconfigCheck('cut_attack_surface', 'grsec', 'LATENCYTOP', 'is not set')]
547 l += [KconfigCheck('cut_attack_surface', 'grsec', 'KCOV', 'is not set')]
548 l += [KconfigCheck('cut_attack_surface', 'grsec', 'PROVIDE_OHCI1394_DMA_INIT', 'is not set')]
549 l += [KconfigCheck('cut_attack_surface', 'grsec', 'SUNRPC_DEBUG', 'is not set')]
550 l += [AND(KconfigCheck('cut_attack_surface', 'grsec', 'PTDUMP_DEBUGFS', 'is not set'),
551 KconfigCheck('cut_attack_surface', 'grsec', 'X86_PTDUMP', 'is not set'))]
553 # 'cut_attack_surface', 'maintainer'
554 l += [KconfigCheck('cut_attack_surface', 'maintainer', 'DRM_LEGACY', 'is not set')] # recommended by Daniel Vetter in /issues/38
555 l += [KconfigCheck('cut_attack_surface', 'maintainer', 'FB', 'is not set')] # recommended by Daniel Vetter in /issues/38
556 l += [KconfigCheck('cut_attack_surface', 'maintainer', 'VT', 'is not set')] # recommended by Daniel Vetter in /issues/38
557 l += [KconfigCheck('cut_attack_surface', 'maintainer', 'BLK_DEV_FD', 'is not set')] # recommended by Denis Efremov in /pull/54
559 # 'cut_attack_surface', 'grapheneos'
560 l += [KconfigCheck('cut_attack_surface', 'grapheneos', 'AIO', 'is not set')]
562 # 'cut_attack_surface', 'clipos'
563 l += [KconfigCheck('cut_attack_surface', 'clipos', 'STAGING', 'is not set')]
564 l += [KconfigCheck('cut_attack_surface', 'clipos', 'KSM', 'is not set')] # to prevent FLUSH+RELOAD attack
565 # l += [KconfigCheck('cut_attack_surface', 'clipos', 'IKCONFIG', 'is not set')] # no, IKCONFIG is needed for this check :)
566 l += [KconfigCheck('cut_attack_surface', 'clipos', 'KALLSYMS', 'is not set')]
567 l += [KconfigCheck('cut_attack_surface', 'clipos', 'X86_VSYSCALL_EMULATION', 'is not set')]
568 l += [KconfigCheck('cut_attack_surface', 'clipos', 'MAGIC_SYSRQ', 'is not set')]
569 l += [KconfigCheck('cut_attack_surface', 'clipos', 'KEXEC_FILE', 'is not set')] # refers to LOCKDOWN (permissive)
570 l += [KconfigCheck('cut_attack_surface', 'clipos', 'USER_NS', 'is not set')] # user.max_user_namespaces=0
571 l += [KconfigCheck('cut_attack_surface', 'clipos', 'X86_MSR', 'is not set')] # refers to LOCKDOWN
572 l += [KconfigCheck('cut_attack_surface', 'clipos', 'X86_CPUID', 'is not set')]
573 l += [KconfigCheck('cut_attack_surface', 'clipos', 'X86_IOPL_IOPERM', 'is not set')] # refers to LOCKDOWN
574 l += [KconfigCheck('cut_attack_surface', 'clipos', 'ACPI_TABLE_UPGRADE', 'is not set')] # refers to LOCKDOWN
575 l += [KconfigCheck('cut_attack_surface', 'clipos', 'EFI_CUSTOM_SSDT_OVERLAYS', 'is not set')]
576 l += [AND(KconfigCheck('cut_attack_surface', 'clipos', 'LDISC_AUTOLOAD', 'is not set'),
577 PresenceCheck('LDISC_AUTOLOAD', 'kconfig'))]
578 if arch in ('X86_64', 'X86_32'):
579 l += [KconfigCheck('cut_attack_surface', 'clipos', 'X86_INTEL_TSX_MODE_OFF', 'y')] # tsx=off
581 # 'cut_attack_surface', 'lockdown'
582 l += [KconfigCheck('cut_attack_surface', 'lockdown', 'EFI_TEST', 'is not set')] # refers to LOCKDOWN
583 l += [KconfigCheck('cut_attack_surface', 'lockdown', 'BPF_SYSCALL', 'is not set')] # refers to LOCKDOWN
584 l += [KconfigCheck('cut_attack_surface', 'lockdown', 'MMIOTRACE_TEST', 'is not set')] # refers to LOCKDOWN
585 l += [KconfigCheck('cut_attack_surface', 'lockdown', 'KPROBES', 'is not set')] # refers to LOCKDOWN
587 # 'cut_attack_surface', 'my'
588 l += [OR(KconfigCheck('cut_attack_surface', 'my', 'TRIM_UNUSED_KSYMS', 'y'),
590 l += [KconfigCheck('cut_attack_surface', 'my', 'MMIOTRACE', 'is not set')] # refers to LOCKDOWN (permissive)
591 l += [KconfigCheck('cut_attack_surface', 'my', 'LIVEPATCH', 'is not set')]
592 l += [KconfigCheck('cut_attack_surface', 'my', 'IP_DCCP', 'is not set')]
593 l += [KconfigCheck('cut_attack_surface', 'my', 'IP_SCTP', 'is not set')]
594 l += [KconfigCheck('cut_attack_surface', 'my', 'FTRACE', 'is not set')] # refers to LOCKDOWN
595 l += [KconfigCheck('cut_attack_surface', 'my', 'VIDEO_VIVID', 'is not set')]
596 l += [KconfigCheck('cut_attack_surface', 'my', 'INPUT_EVBUG', 'is not set')] # Can be used as a keylogger
599 if arch in ('X86_64', 'ARM64', 'X86_32'):
600 l += [KconfigCheck('harden_userspace', 'defconfig', 'INTEGRITY', 'y')]
602 l += [KconfigCheck('harden_userspace', 'my', 'INTEGRITY', 'y')]
604 l += [KconfigCheck('harden_userspace', 'defconfig', 'ARM64_MTE', 'y')]
605 if arch in ('ARM', 'X86_32'):
606 l += [KconfigCheck('harden_userspace', 'defconfig', 'VMSPLIT_3G', 'y')]
607 if arch in ('X86_64', 'ARM64'):
608 l += [KconfigCheck('harden_userspace', 'clipos', 'ARCH_MMAP_RND_BITS', '32')]
609 if arch in ('X86_32', 'ARM'):
610 l += [KconfigCheck('harden_userspace', 'my', 'ARCH_MMAP_RND_BITS', '16')]
612 # l += [KconfigCheck('feature_test', 'my', 'LKDTM', 'm')] # only for debugging!
615 def print_unknown_options(checklist, parsed_options):
619 if not hasattr(o1, 'opts'):
620 known_options.append(o1.name)
623 if not hasattr(o2, 'opts'):
624 if hasattr(o2, 'name'):
625 known_options.append(o2.name)
628 if hasattr(o3, 'opts'):
629 sys.exit('[!] ERROR: unexpected ComplexOptCheck inside {}'.format(o2.name))
630 if hasattr(o3, 'name'):
631 known_options.append(o3.name)
633 for option, value in parsed_options.items():
634 if option not in known_options:
635 print('[?] No check for option {} ({})'.format(option, value))
638 def print_checklist(mode, checklist, with_results):
642 opt = [o.name, o.type, o.expected, o.decision, o.reason]
646 print(json.dumps(opts))
653 print('=' * sep_line_len)
654 print('{:^40}|{:^7}|{:^12}|{:^10}|{:^18}'.format('option name', 'type', 'desired val', 'decision', 'reason'), end='')
656 print('| {}'.format('check result'), end='')
658 print('=' * sep_line_len)
661 for opt in checklist:
663 if mode == 'show_ok':
664 if not opt.result.startswith('OK'):
666 if mode == 'show_fail':
667 if not opt.result.startswith('FAIL'):
669 opt.table_print(mode, with_results)
671 if mode == 'verbose':
672 print('-' * sep_line_len)
677 fail_count = len(list(filter(lambda opt: opt.result.startswith('FAIL'), checklist)))
679 ok_count = len(list(filter(lambda opt: opt.result.startswith('OK'), checklist)))
681 if mode == 'show_ok':
682 fail_suppressed = ' (suppressed in output)'
683 if mode == 'show_fail':
684 ok_suppressed = ' (suppressed in output)'
686 print('[+] Config check is finished: \'OK\' - {}{} / \'FAIL\' - {}{}'.format(ok_count, ok_suppressed, fail_count, fail_suppressed))
689 def populate_opt_with_data(opt, parsed_options, kernel_version):
690 if hasattr(opt, 'opts'):
691 # prepare ComplexOptCheck
693 if hasattr(o, 'opts'):
694 # Recursion for nested ComplexOptChecks
695 populate_opt_with_data(o, parsed_options, kernel_version)
696 if hasattr(o, 'state'):
697 o.state = parsed_options.get(o.name, None)
698 if hasattr(o, 'ver'):
699 o.ver = kernel_version
701 # prepare simple check, opt.state is mandatory
702 if not hasattr(opt, 'state'):
703 sys.exit('[!] ERROR: bad simple check {}'.format(vars(opt)))
704 opt.state = parsed_options.get(opt.name, None)
707 def populate_with_data(checklist, parsed_options, kernel_version):
708 for opt in checklist:
709 populate_opt_with_data(opt, parsed_options, kernel_version)
712 def perform_checks(checklist):
713 for opt in checklist:
717 def parse_kconfig_file(parsed_options, fname):
718 with open(fname, 'r') as f:
719 opt_is_on = re.compile("CONFIG_[a-zA-Z0-9_]*=[a-zA-Z0-9_\"]*")
720 opt_is_off = re.compile("# CONFIG_[a-zA-Z0-9_]* is not set")
722 for line in f.readlines():
727 if opt_is_on.match(line):
728 option, value = line.split('=', 1)
729 elif opt_is_off.match(line):
730 option, value = line[2:].split(' ', 1)
731 if value != 'is not set':
732 sys.exit('[!] ERROR: bad disabled kconfig option "{}"'.format(line))
734 if option in parsed_options:
735 sys.exit('[!] ERROR: kconfig option "{}" exists multiple times'.format(line))
738 parsed_options[option] = value
740 return parsed_options
746 # - reporting about unknown kernel options in the kconfig
747 # - verbose printing of ComplexOptCheck items
748 # * json mode for printing the results in JSON format
749 report_modes = ['verbose', 'json', 'show_ok', 'show_fail']
750 supported_archs = ['X86_64', 'X86_32', 'ARM64', 'ARM']
751 parser = ArgumentParser(prog='kconfig-hardened-check',
752 description='A tool for checking the security hardening options of the Linux kernel')
753 parser.add_argument('--version', action='version', version='%(prog)s ' + __version__)
754 parser.add_argument('-p', '--print', choices=supported_archs,
755 help='print security hardening preferences for the selected architecture')
756 parser.add_argument('-c', '--config',
757 help='check the kernel kconfig file against these preferences')
758 parser.add_argument('-m', '--mode', choices=report_modes,
759 help='choose the report mode')
760 args = parser.parse_args()
766 print('[+] Special report mode: {}'.format(mode))
768 config_checklist = []
772 print('[+] Kconfig file to check: {}'.format(args.config))
774 arch, msg = detect_arch(args.config, supported_archs)
776 sys.exit('[!] ERROR: {}'.format(msg))
778 print('[+] Detected architecture: {}'.format(arch))
780 kernel_version, msg = detect_version(args.config)
781 if not kernel_version:
782 sys.exit('[!] ERROR: {}'.format(msg))
784 print('[+] Detected kernel version: {}.{}'.format(kernel_version[0], kernel_version[1]))
786 # add relevant kconfig checks to the checklist
787 add_kconfig_checks(config_checklist, arch)
789 # populate the checklist with the parsed kconfig data
790 parsed_kconfig_options = OrderedDict()
791 parse_kconfig_file(parsed_kconfig_options, args.config)
792 populate_with_data(config_checklist, parsed_kconfig_options, kernel_version)
794 # now everything is ready for performing the checks
795 perform_checks(config_checklist)
797 # finally print the results
798 if mode == 'verbose':
799 print_unknown_options(config_checklist, parsed_kconfig_options)
800 print_checklist(mode, config_checklist, True)
805 if mode in ('show_ok', 'show_fail'):
806 sys.exit('[!] ERROR: wrong mode "{}" for --print'.format(mode))
808 add_kconfig_checks(config_checklist, arch)
810 print('[+] Printing kernel security hardening preferences for {}...'.format(arch))
811 print_checklist(mode, config_checklist, False)
817 if __name__ == '__main__':