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 # Constructor without the 'expected' parameter is for option presence checks (any value is OK)
90 def __init__(self, reason, decision, name, expected=None):
91 if not reason or not decision or not name:
92 sys.exit('[!] ERROR: invalid {} check for "{}"'.format(self.__class__.__name__, name))
94 self.expected = expected
95 self.decision = decision
101 # handle the option presence check
102 if self.expected is None:
103 if self.state is None:
104 self.result = 'FAIL: not present'
106 self.result = 'OK: is present'
109 # handle the option value check
110 if self.expected == self.state:
112 elif self.state is None:
113 if self.expected == 'is not set':
114 self.result = 'OK: not found'
116 self.result = 'FAIL: not found'
118 self.result = 'FAIL: "' + self.state + '"'
120 def table_print(self, _mode, with_results):
121 if self.expected is None:
124 expected = self.expected
125 print('{:<40}|{:^7}|{:^12}|{:^10}|{:^18}'.format(self.name, self.type, expected, self.decision, self.reason), end='')
127 print('| {}'.format(self.result), end='')
130 class KconfigCheck(OptCheck):
131 def __init__(self, *args, **kwargs):
132 super().__init__(*args, **kwargs)
133 self.name = 'CONFIG_' + self.name
139 def json_dump(self, with_results):
140 dump = [self.name, self.type, self.expected, self.decision, self.reason]
142 dump.append(self.result)
147 def __init__(self, ver_expected):
148 self.ver_expected = ver_expected
157 if self.ver[0] > self.ver_expected[0]:
158 self.result = 'OK: version >= ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
160 if self.ver[0] < self.ver_expected[0]:
161 self.result = 'FAIL: version < ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
163 if self.ver[1] >= self.ver_expected[1]:
164 self.result = 'OK: version >= ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
166 self.result = 'FAIL: version < ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
168 def table_print(self, _mode, with_results):
169 ver_req = 'kernel version >= ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
170 print('{:<91}'.format(ver_req), end='')
172 print('| {}'.format(self.result), end='')
175 class ComplexOptCheck:
176 def __init__(self, *opts):
179 sys.exit('[!] ERROR: empty {} check'.format(self.__class__.__name__))
180 if len(self.opts) == 1:
181 sys.exit('[!] ERROR: useless {} check'.format(self.__class__.__name__))
182 if not isinstance(opts[0], KconfigCheck):
183 sys.exit('[!] ERROR: invalid {} check: {}'.format(self.__class__.__name__, opts))
188 return self.opts[0].name
196 return self.opts[0].expected
200 return self.opts[0].decision
204 return self.opts[0].reason
206 def table_print(self, mode, with_results):
207 if mode == 'verbose':
208 print(' {:87}'.format('<<< ' + self.__class__.__name__ + ' >>>'), end='')
210 print('| {}'.format(self.result), end='')
213 o.table_print(mode, with_results)
216 o.table_print(mode, False)
218 print('| {}'.format(self.result), end='')
220 def json_dump(self, with_results):
221 dump = self.opts[0].json_dump(False)
223 dump.append(self.result)
227 class OR(ComplexOptCheck):
228 # self.opts[0] is the option that this OR-check is about.
230 # OR(<X_is_hardened>, <X_is_disabled>)
231 # OR(<X_is_hardened>, <old_X_is_hardened>)
234 sys.exit('[!] ERROR: invalid OR check')
235 for i, opt in enumerate(self.opts):
237 if opt.result.startswith('OK'):
238 if opt.result == 'OK' and i != 0:
239 # Simple OK is not enough for additional checks, add more info:
240 self.result = 'OK: {} "{}"'.format(opt.name, opt.expected)
242 self.result = opt.result
244 self.result = self.opts[0].result
247 class AND(ComplexOptCheck):
248 # self.opts[0] is the option that this AND-check is about.
250 # AND(<suboption>, <main_option>)
251 # Suboption is not checked if checking of the main_option is failed.
252 # AND(<X_is_disabled>, <old_X_is_disabled>)
254 for i, opt in reversed(list(enumerate(self.opts))):
257 self.result = opt.result
259 if not opt.result.startswith('OK'):
260 # This FAIL is caused by additional checks,
261 # and not by the main option that this AND-check is about.
262 # Describe the reason of the FAIL.
263 if opt.result.startswith('FAIL: \"') or opt.result == 'FAIL: not found':
264 self.result = 'FAIL: {} not "{}"'.format(opt.name, opt.expected)
265 elif opt.result == 'FAIL: not present':
266 self.result = 'FAIL: {} not present'.format(opt.name)
268 # This FAIL message is self-explaining.
269 self.result = opt.result
271 sys.exit('[!] ERROR: invalid AND check')
274 def detect_arch(fname, archs):
275 with open(fname, 'r') as f:
276 arch_pattern = re.compile("CONFIG_[a-zA-Z0-9_]*=y")
278 for line in f.readlines():
279 if arch_pattern.match(line):
280 option, _ = line[7:].split('=', 1)
285 return None, 'more than one supported architecture is detected'
287 return None, 'failed to detect architecture'
291 def detect_version(fname):
292 with open(fname, 'r') as f:
293 ver_pattern = re.compile("# Linux/.* Kernel Configuration")
294 for line in f.readlines():
295 if ver_pattern.match(line):
299 ver_numbers = ver_str.split('.')
300 if len(ver_numbers) < 3 or not ver_numbers[0].isdigit() or not ver_numbers[1].isdigit():
301 msg = 'failed to parse the version "' + ver_str + '"'
303 return (int(ver_numbers[0]), int(ver_numbers[1])), None
304 return None, 'no kernel version detected'
307 def add_kconfig_checks(l, arch):
308 # Calling the KconfigCheck class constructor:
309 # KconfigCheck(reason, decision, name, expected)
311 modules_not_set = KconfigCheck('cut_attack_surface', 'kspp', 'MODULES', 'is not set')
312 devmem_not_set = KconfigCheck('cut_attack_surface', 'kspp', 'DEVMEM', 'is not set') # refers to LOCKDOWN
313 bpf_syscall_not_set = KconfigCheck('cut_attack_surface', 'lockdown', 'BPF_SYSCALL', 'is not set') # refers to LOCKDOWN
314 efi_not_set = KconfigCheck('cut_attack_surface', 'my', 'EFI', 'is not set')
316 # 'self_protection', 'defconfig'
317 l += [KconfigCheck('self_protection', 'defconfig', 'BUG', 'y')]
318 l += [KconfigCheck('self_protection', 'defconfig', 'SLUB_DEBUG', 'y')]
319 l += [KconfigCheck('self_protection', 'defconfig', 'GCC_PLUGINS', 'y')]
320 l += [OR(KconfigCheck('self_protection', 'defconfig', 'STACKPROTECTOR_STRONG', 'y'),
321 KconfigCheck('self_protection', 'defconfig', 'CC_STACKPROTECTOR_STRONG', 'y'))]
322 l += [OR(KconfigCheck('self_protection', 'defconfig', 'STRICT_KERNEL_RWX', 'y'),
323 KconfigCheck('self_protection', 'defconfig', 'DEBUG_RODATA', 'y'))] # before v4.11
324 l += [OR(KconfigCheck('self_protection', 'defconfig', 'STRICT_MODULE_RWX', 'y'),
325 KconfigCheck('self_protection', 'defconfig', 'DEBUG_SET_MODULE_RONX', 'y'),
326 modules_not_set)] # DEBUG_SET_MODULE_RONX was before v4.11
327 l += [OR(KconfigCheck('self_protection', 'defconfig', 'REFCOUNT_FULL', 'y'),
328 VersionCheck((5, 5)))] # REFCOUNT_FULL is enabled by default since v5.5
329 l += [KconfigCheck('self_protection', 'defconfig', 'THREAD_INFO_IN_TASK', 'y')]
330 iommu_support_is_set = KconfigCheck('self_protection', 'defconfig', 'IOMMU_SUPPORT', 'y')
331 l += [iommu_support_is_set] # is needed for mitigating DMA attacks
332 if arch in ('X86_64', 'ARM64', 'X86_32'):
333 l += [KconfigCheck('self_protection', 'defconfig', 'RANDOMIZE_BASE', 'y')]
334 if arch in ('X86_64', 'ARM64'):
335 l += [KconfigCheck('self_protection', 'defconfig', 'VMAP_STACK', 'y')]
336 if arch in ('X86_64', 'X86_32'):
337 l += [KconfigCheck('self_protection', 'defconfig', 'MICROCODE', 'y')] # is needed for mitigating CPU bugs
338 l += [KconfigCheck('self_protection', 'defconfig', 'RETPOLINE', 'y')]
339 l += [KconfigCheck('self_protection', 'defconfig', 'X86_SMAP', 'y')]
340 l += [KconfigCheck('self_protection', 'defconfig', 'SYN_COOKIES', 'y')] # another reason?
341 l += [OR(KconfigCheck('self_protection', 'defconfig', 'X86_UMIP', 'y'),
342 KconfigCheck('self_protection', 'defconfig', 'X86_INTEL_UMIP', 'y'))]
343 if arch in ('ARM64', 'ARM'):
344 l += [KconfigCheck('self_protection', 'defconfig', 'STACKPROTECTOR_PER_TASK', 'y')]
346 l += [KconfigCheck('self_protection', 'defconfig', 'PAGE_TABLE_ISOLATION', 'y')]
347 l += [KconfigCheck('self_protection', 'defconfig', 'RANDOMIZE_MEMORY', 'y')]
348 l += [AND(KconfigCheck('self_protection', 'defconfig', 'INTEL_IOMMU', 'y'),
349 iommu_support_is_set)]
350 l += [AND(KconfigCheck('self_protection', 'defconfig', 'AMD_IOMMU', 'y'),
351 iommu_support_is_set)]
353 l += [KconfigCheck('self_protection', 'defconfig', 'ARM64_PAN', 'y')]
354 l += [KconfigCheck('self_protection', 'defconfig', 'ARM64_EPAN', 'y')]
355 l += [KconfigCheck('self_protection', 'defconfig', 'UNMAP_KERNEL_AT_EL0', 'y')]
356 l += [OR(KconfigCheck('self_protection', 'defconfig', 'HARDEN_EL2_VECTORS', 'y'),
357 AND(KconfigCheck('self_protection', 'defconfig', 'RANDOMIZE_BASE', 'y'),
358 VersionCheck((5, 9))))] # HARDEN_EL2_VECTORS was included in RANDOMIZE_BASE in v5.9
359 l += [KconfigCheck('self_protection', 'defconfig', 'RODATA_FULL_DEFAULT_ENABLED', 'y')]
360 l += [KconfigCheck('self_protection', 'defconfig', 'ARM64_PTR_AUTH_KERNEL', 'y')]
361 l += [KconfigCheck('self_protection', 'defconfig', 'ARM64_BTI_KERNEL', 'y')]
362 l += [OR(KconfigCheck('self_protection', 'defconfig', 'HARDEN_BRANCH_PREDICTOR', 'y'),
363 VersionCheck((5, 10)))] # HARDEN_BRANCH_PREDICTOR is enabled by default since v5.10
364 l += [KconfigCheck('self_protection', 'defconfig', 'MITIGATE_SPECTRE_BRANCH_HISTORY', 'y')]
365 l += [KconfigCheck('self_protection', 'defconfig', 'ARM64_MTE', 'y')]
367 l += [KconfigCheck('self_protection', 'defconfig', 'CPU_SW_DOMAIN_PAN', 'y')]
368 l += [KconfigCheck('self_protection', 'defconfig', 'HARDEN_BRANCH_PREDICTOR', 'y')]
369 l += [KconfigCheck('self_protection', 'defconfig', 'HARDEN_BRANCH_HISTORY', 'y')]
371 # 'self_protection', 'kspp'
372 l += [KconfigCheck('self_protection', 'kspp', 'SECURITY_DMESG_RESTRICT', 'y')]
373 l += [KconfigCheck('self_protection', 'kspp', 'BUG_ON_DATA_CORRUPTION', 'y')]
374 l += [KconfigCheck('self_protection', 'kspp', 'DEBUG_WX', 'y')]
375 l += [KconfigCheck('self_protection', 'kspp', 'SCHED_STACK_END_CHECK', 'y')]
376 l += [KconfigCheck('self_protection', 'kspp', 'SLAB_FREELIST_HARDENED', 'y')]
377 l += [KconfigCheck('self_protection', 'kspp', 'SLAB_FREELIST_RANDOM', 'y')]
378 l += [KconfigCheck('self_protection', 'kspp', 'SHUFFLE_PAGE_ALLOCATOR', 'y')]
379 l += [KconfigCheck('self_protection', 'kspp', 'FORTIFY_SOURCE', 'y')]
380 l += [KconfigCheck('self_protection', 'kspp', 'DEBUG_LIST', 'y')]
381 l += [KconfigCheck('self_protection', 'kspp', 'DEBUG_SG', 'y')]
382 l += [KconfigCheck('self_protection', 'kspp', 'DEBUG_CREDENTIALS', 'y')]
383 l += [KconfigCheck('self_protection', 'kspp', 'DEBUG_NOTIFIERS', 'y')]
384 l += [KconfigCheck('self_protection', 'kspp', 'INIT_ON_ALLOC_DEFAULT_ON', 'y')]
385 l += [KconfigCheck('self_protection', 'kspp', 'GCC_PLUGIN_LATENT_ENTROPY', 'y')]
386 l += [KconfigCheck('self_protection', 'kspp', 'KFENCE', 'y')]
387 l += [KconfigCheck('self_protection', 'kspp', 'WERROR', 'y')]
388 l += [KconfigCheck('self_protection', 'kspp', 'IOMMU_DEFAULT_DMA_STRICT', 'y')]
389 randstruct_is_set = KconfigCheck('self_protection', 'kspp', 'GCC_PLUGIN_RANDSTRUCT', 'y')
390 l += [randstruct_is_set]
391 hardened_usercopy_is_set = KconfigCheck('self_protection', 'kspp', 'HARDENED_USERCOPY', 'y')
392 l += [hardened_usercopy_is_set]
393 l += [AND(KconfigCheck('self_protection', 'kspp', 'HARDENED_USERCOPY_FALLBACK', 'is not set'),
394 hardened_usercopy_is_set)]
395 l += [AND(KconfigCheck('self_protection', 'kspp', 'HARDENED_USERCOPY_PAGESPAN', 'is not set'),
396 hardened_usercopy_is_set)]
397 l += [OR(KconfigCheck('self_protection', 'kspp', 'MODULE_SIG', 'y'),
399 l += [OR(KconfigCheck('self_protection', 'kspp', 'MODULE_SIG_ALL', 'y'),
401 l += [OR(KconfigCheck('self_protection', 'kspp', 'MODULE_SIG_SHA512', 'y'),
403 l += [OR(KconfigCheck('self_protection', 'kspp', 'MODULE_SIG_FORCE', 'y'),
404 modules_not_set)] # refers to LOCKDOWN
405 l += [OR(KconfigCheck('self_protection', 'kspp', 'INIT_STACK_ALL_ZERO', 'y'),
406 KconfigCheck('self_protection', 'kspp', 'GCC_PLUGIN_STRUCTLEAK_BYREF_ALL', 'y'))]
407 l += [OR(KconfigCheck('self_protection', 'kspp', 'INIT_ON_FREE_DEFAULT_ON', 'y'),
408 KconfigCheck('self_protection', 'kspp', 'PAGE_POISONING_ZERO', 'y'))]
409 # CONFIG_INIT_ON_FREE_DEFAULT_ON was added in v5.3.
410 # CONFIG_PAGE_POISONING_ZERO was removed in v5.11.
411 # Starting from v5.11 CONFIG_PAGE_POISONING unconditionally checks
412 # the 0xAA poison pattern on allocation.
413 # That brings higher performance penalty.
414 if arch in ('X86_64', 'ARM64', 'X86_32'):
415 stackleak_is_set = KconfigCheck('self_protection', 'kspp', 'GCC_PLUGIN_STACKLEAK', 'y')
416 l += [stackleak_is_set]
417 l += [KconfigCheck('self_protection', 'kspp', 'RANDOMIZE_KSTACK_OFFSET_DEFAULT', 'y')]
418 l += [KconfigCheck('self_protection', 'kspp', 'SCHED_CORE', 'y')]
419 if arch in ('X86_64', 'X86_32'):
420 l += [KconfigCheck('self_protection', 'kspp', 'DEFAULT_MMAP_MIN_ADDR', '65536')]
421 if arch in ('ARM64', 'ARM'):
422 l += [KconfigCheck('self_protection', 'kspp', 'DEFAULT_MMAP_MIN_ADDR', '32768')]
423 l += [KconfigCheck('self_protection', 'kspp', 'SYN_COOKIES', 'y')] # another reason?
425 l += [KconfigCheck('self_protection', 'kspp', 'ARM64_SW_TTBR0_PAN', 'y')]
427 l += [KconfigCheck('self_protection', 'kspp', 'PAGE_TABLE_ISOLATION', 'y')]
428 l += [KconfigCheck('self_protection', 'kspp', 'HIGHMEM64G', 'y')]
429 l += [KconfigCheck('self_protection', 'kspp', 'X86_PAE', 'y')]
431 # 'self_protection', 'maintainer'
432 ubsan_bounds_is_set = KconfigCheck('self_protection', 'maintainer', 'UBSAN_BOUNDS', 'y') # only array index bounds checking
433 l += [ubsan_bounds_is_set] # recommended by Kees Cook in /issues/53
434 if arch in ('X86_64', 'ARM64', 'X86_32'): # ARCH_HAS_UBSAN_SANITIZE_ALL is not enabled for ARM
435 l += [AND(KconfigCheck('self_protection', 'maintainer', 'UBSAN_SANITIZE_ALL', 'y'),
436 ubsan_bounds_is_set)] # recommended by Kees Cook in /issues/53
437 l += [AND(KconfigCheck('self_protection', 'maintainer', 'UBSAN_TRAP', 'y'),
438 ubsan_bounds_is_set)] # recommended by Kees Cook in /issues/53
440 # 'self_protection', 'clipos'
441 l += [KconfigCheck('self_protection', 'clipos', 'DEBUG_VIRTUAL', 'y')]
442 l += [KconfigCheck('self_protection', 'clipos', 'STATIC_USERMODEHELPER', 'y')] # needs userspace support
443 l += [OR(KconfigCheck('self_protection', 'clipos', 'EFI_DISABLE_PCI_DMA', 'y'),
445 l += [KconfigCheck('self_protection', 'clipos', 'SLAB_MERGE_DEFAULT', 'is not set')] # slab_nomerge
446 l += [KconfigCheck('self_protection', 'clipos', 'RANDOM_TRUST_BOOTLOADER', 'is not set')]
447 l += [KconfigCheck('self_protection', 'clipos', 'RANDOM_TRUST_CPU', 'is not set')]
448 l += [AND(KconfigCheck('self_protection', 'clipos', 'GCC_PLUGIN_RANDSTRUCT_PERFORMANCE', 'is not set'),
450 if arch in ('X86_64', 'ARM64', 'X86_32'):
451 l += [AND(KconfigCheck('self_protection', 'clipos', 'STACKLEAK_METRICS', 'is not set'),
453 l += [AND(KconfigCheck('self_protection', 'clipos', 'STACKLEAK_RUNTIME_DISABLE', 'is not set'),
455 if arch in ('X86_64', 'X86_32'):
456 l += [AND(KconfigCheck('self_protection', 'clipos', 'INTEL_IOMMU_DEFAULT_ON', 'y'),
457 iommu_support_is_set)]
459 l += [AND(KconfigCheck('self_protection', 'clipos', 'INTEL_IOMMU_SVM', 'y'),
460 iommu_support_is_set)]
462 l += [AND(KconfigCheck('self_protection', 'clipos', 'INTEL_IOMMU', 'y'),
463 iommu_support_is_set)]
465 # 'self_protection', 'my'
466 l += [OR(KconfigCheck('self_protection', 'my', 'RESET_ATTACK_MITIGATION', 'y'),
467 efi_not_set)] # needs userspace support (systemd)
469 l += [KconfigCheck('self_protection', 'my', 'SLS', 'y')] # vs CVE-2021-26341 in Straight-Line-Speculation
470 l += [AND(KconfigCheck('self_protection', 'my', 'AMD_IOMMU_V2', 'y'),
471 iommu_support_is_set)]
473 l += [KconfigCheck('self_protection', 'my', 'SHADOW_CALL_STACK', 'y')] # depends on clang, maybe it's alternative to STACKPROTECTOR_STRONG
474 l += [KconfigCheck('self_protection', 'my', 'KASAN_HW_TAGS', 'y')]
475 cfi_clang_is_set = KconfigCheck('self_protection', 'my', 'CFI_CLANG', 'y')
476 l += [cfi_clang_is_set]
477 l += [AND(KconfigCheck('self_protection', 'my', 'CFI_PERMISSIVE', 'is not set'),
481 if arch in ('X86_64', 'ARM64', 'X86_32'):
482 l += [KconfigCheck('security_policy', 'defconfig', 'SECURITY', 'y')] # and choose your favourite LSM
484 l += [KconfigCheck('security_policy', 'kspp', 'SECURITY', 'y')] # and choose your favourite LSM
485 l += [KconfigCheck('security_policy', 'kspp', 'SECURITY_YAMA', 'y')]
486 l += [OR(KconfigCheck('security_policy', 'my', 'SECURITY_WRITABLE_HOOKS', 'is not set'),
487 KconfigCheck('security_policy', 'kspp', 'SECURITY_SELINUX_DISABLE', 'is not set'))]
488 l += [KconfigCheck('security_policy', 'clipos', 'SECURITY_LOCKDOWN_LSM', 'y')]
489 l += [KconfigCheck('security_policy', 'clipos', 'SECURITY_LOCKDOWN_LSM_EARLY', 'y')]
490 l += [KconfigCheck('security_policy', 'clipos', 'LOCK_DOWN_KERNEL_FORCE_CONFIDENTIALITY', 'y')]
491 l += [KconfigCheck('security_policy', 'my', 'SECURITY_SAFESETID', 'y')]
492 loadpin_is_set = KconfigCheck('security_policy', 'my', 'SECURITY_LOADPIN', 'y')
493 l += [loadpin_is_set] # needs userspace support
494 l += [AND(KconfigCheck('security_policy', 'my', 'SECURITY_LOADPIN_ENFORCE', 'y'),
497 # 'cut_attack_surface', 'defconfig'
498 l += [OR(KconfigCheck('cut_attack_surface', 'defconfig', 'BPF_UNPRIV_DEFAULT_OFF', 'y'),
499 bpf_syscall_not_set)] # see unprivileged_bpf_disabled
500 l += [KconfigCheck('cut_attack_surface', 'defconfig', 'SECCOMP', 'y')]
501 l += [KconfigCheck('cut_attack_surface', 'defconfig', 'SECCOMP_FILTER', 'y')]
502 if arch in ('X86_64', 'ARM64', 'X86_32'):
503 l += [OR(KconfigCheck('cut_attack_surface', 'defconfig', 'STRICT_DEVMEM', 'y'),
504 devmem_not_set)] # refers to LOCKDOWN
506 # 'cut_attack_surface', 'kspp'
507 l += [KconfigCheck('cut_attack_surface', 'kspp', 'ACPI_CUSTOM_METHOD', 'is not set')] # refers to LOCKDOWN
508 l += [KconfigCheck('cut_attack_surface', 'kspp', 'COMPAT_BRK', 'is not set')]
509 l += [KconfigCheck('cut_attack_surface', 'kspp', 'DEVKMEM', 'is not set')] # refers to LOCKDOWN
510 l += [KconfigCheck('cut_attack_surface', 'kspp', 'COMPAT_VDSO', 'is not set')]
511 l += [KconfigCheck('cut_attack_surface', 'kspp', 'BINFMT_MISC', 'is not set')]
512 l += [KconfigCheck('cut_attack_surface', 'kspp', 'INET_DIAG', 'is not set')]
513 l += [KconfigCheck('cut_attack_surface', 'kspp', 'KEXEC', 'is not set')] # refers to LOCKDOWN
514 l += [KconfigCheck('cut_attack_surface', 'kspp', 'PROC_KCORE', 'is not set')] # refers to LOCKDOWN
515 l += [KconfigCheck('cut_attack_surface', 'kspp', 'LEGACY_PTYS', 'is not set')]
516 l += [KconfigCheck('cut_attack_surface', 'kspp', 'HIBERNATION', 'is not set')] # refers to LOCKDOWN
517 l += [KconfigCheck('cut_attack_surface', 'kspp', 'IA32_EMULATION', 'is not set')]
518 l += [KconfigCheck('cut_attack_surface', 'kspp', 'X86_X32', 'is not set')]
519 l += [KconfigCheck('cut_attack_surface', 'kspp', 'MODIFY_LDT_SYSCALL', 'is not set')]
520 l += [KconfigCheck('cut_attack_surface', 'kspp', 'OABI_COMPAT', 'is not set')]
521 l += [modules_not_set]
522 l += [devmem_not_set]
523 l += [OR(KconfigCheck('cut_attack_surface', 'kspp', 'IO_STRICT_DEVMEM', 'y'),
524 devmem_not_set)] # refers to LOCKDOWN
526 l += [OR(KconfigCheck('cut_attack_surface', 'kspp', 'STRICT_DEVMEM', 'y'),
527 devmem_not_set)] # refers to LOCKDOWN
529 l += [KconfigCheck('cut_attack_surface', 'kspp', 'LEGACY_VSYSCALL_NONE', 'y')] # 'vsyscall=none'
531 # 'cut_attack_surface', 'grsec'
532 l += [KconfigCheck('cut_attack_surface', 'grsec', 'ZSMALLOC_STAT', 'is not set')]
533 l += [KconfigCheck('cut_attack_surface', 'grsec', 'PAGE_OWNER', 'is not set')]
534 l += [KconfigCheck('cut_attack_surface', 'grsec', 'DEBUG_KMEMLEAK', 'is not set')]
535 l += [KconfigCheck('cut_attack_surface', 'grsec', 'BINFMT_AOUT', 'is not set')]
536 l += [KconfigCheck('cut_attack_surface', 'grsec', 'KPROBE_EVENTS', 'is not set')]
537 l += [KconfigCheck('cut_attack_surface', 'grsec', 'UPROBE_EVENTS', 'is not set')]
538 l += [KconfigCheck('cut_attack_surface', 'grsec', 'GENERIC_TRACER', 'is not set')] # refers to LOCKDOWN
539 l += [KconfigCheck('cut_attack_surface', 'grsec', 'FUNCTION_TRACER', 'is not set')]
540 l += [KconfigCheck('cut_attack_surface', 'grsec', 'STACK_TRACER', 'is not set')]
541 l += [KconfigCheck('cut_attack_surface', 'grsec', 'HIST_TRIGGERS', 'is not set')]
542 l += [KconfigCheck('cut_attack_surface', 'grsec', 'BLK_DEV_IO_TRACE', 'is not set')]
543 l += [KconfigCheck('cut_attack_surface', 'grsec', 'PROC_VMCORE', 'is not set')]
544 l += [KconfigCheck('cut_attack_surface', 'grsec', 'PROC_PAGE_MONITOR', 'is not set')]
545 l += [KconfigCheck('cut_attack_surface', 'grsec', 'USELIB', 'is not set')]
546 l += [KconfigCheck('cut_attack_surface', 'grsec', 'CHECKPOINT_RESTORE', 'is not set')]
547 l += [KconfigCheck('cut_attack_surface', 'grsec', 'USERFAULTFD', 'is not set')]
548 l += [KconfigCheck('cut_attack_surface', 'grsec', 'HWPOISON_INJECT', 'is not set')]
549 l += [KconfigCheck('cut_attack_surface', 'grsec', 'MEM_SOFT_DIRTY', 'is not set')]
550 l += [KconfigCheck('cut_attack_surface', 'grsec', 'DEVPORT', 'is not set')] # refers to LOCKDOWN
551 l += [KconfigCheck('cut_attack_surface', 'grsec', 'DEBUG_FS', 'is not set')] # refers to LOCKDOWN
552 l += [KconfigCheck('cut_attack_surface', 'grsec', 'NOTIFIER_ERROR_INJECTION', 'is not set')]
553 l += [KconfigCheck('cut_attack_surface', 'grsec', 'FAIL_FUTEX', 'is not set')]
554 l += [KconfigCheck('cut_attack_surface', 'grsec', 'PUNIT_ATOM_DEBUG', 'is not set')]
555 l += [KconfigCheck('cut_attack_surface', 'grsec', 'ACPI_CONFIGFS', 'is not set')]
556 l += [KconfigCheck('cut_attack_surface', 'grsec', 'EDAC_DEBUG', 'is not set')]
557 l += [KconfigCheck('cut_attack_surface', 'grsec', 'DRM_I915_DEBUG', 'is not set')]
558 l += [KconfigCheck('cut_attack_surface', 'grsec', 'BCACHE_CLOSURES_DEBUG', 'is not set')]
559 l += [KconfigCheck('cut_attack_surface', 'grsec', 'DVB_C8SECTPFE', 'is not set')]
560 l += [KconfigCheck('cut_attack_surface', 'grsec', 'MTD_SLRAM', 'is not set')]
561 l += [KconfigCheck('cut_attack_surface', 'grsec', 'MTD_PHRAM', 'is not set')]
562 l += [KconfigCheck('cut_attack_surface', 'grsec', 'IO_URING', 'is not set')]
563 l += [KconfigCheck('cut_attack_surface', 'grsec', 'KCMP', 'is not set')]
564 l += [KconfigCheck('cut_attack_surface', 'grsec', 'RSEQ', 'is not set')]
565 l += [KconfigCheck('cut_attack_surface', 'grsec', 'LATENCYTOP', 'is not set')]
566 l += [KconfigCheck('cut_attack_surface', 'grsec', 'KCOV', 'is not set')]
567 l += [KconfigCheck('cut_attack_surface', 'grsec', 'PROVIDE_OHCI1394_DMA_INIT', 'is not set')]
568 l += [KconfigCheck('cut_attack_surface', 'grsec', 'SUNRPC_DEBUG', 'is not set')]
569 l += [AND(KconfigCheck('cut_attack_surface', 'grsec', 'PTDUMP_DEBUGFS', 'is not set'),
570 KconfigCheck('cut_attack_surface', 'grsec', 'X86_PTDUMP', 'is not set'))]
572 # 'cut_attack_surface', 'maintainer'
573 l += [KconfigCheck('cut_attack_surface', 'maintainer', 'DRM_LEGACY', 'is not set')] # recommended by Daniel Vetter in /issues/38
574 l += [KconfigCheck('cut_attack_surface', 'maintainer', 'FB', 'is not set')] # recommended by Daniel Vetter in /issues/38
575 l += [KconfigCheck('cut_attack_surface', 'maintainer', 'VT', 'is not set')] # recommended by Daniel Vetter in /issues/38
576 l += [KconfigCheck('cut_attack_surface', 'maintainer', 'BLK_DEV_FD', 'is not set')] # recommended by Denis Efremov in /pull/54
578 # 'cut_attack_surface', 'grapheneos'
579 l += [KconfigCheck('cut_attack_surface', 'grapheneos', 'AIO', 'is not set')]
581 # 'cut_attack_surface', 'clipos'
582 l += [KconfigCheck('cut_attack_surface', 'clipos', 'STAGING', 'is not set')]
583 l += [KconfigCheck('cut_attack_surface', 'clipos', 'KSM', 'is not set')] # to prevent FLUSH+RELOAD attack
584 # l += [KconfigCheck('cut_attack_surface', 'clipos', 'IKCONFIG', 'is not set')] # no, IKCONFIG is needed for this check :)
585 l += [KconfigCheck('cut_attack_surface', 'clipos', 'KALLSYMS', 'is not set')]
586 l += [KconfigCheck('cut_attack_surface', 'clipos', 'X86_VSYSCALL_EMULATION', 'is not set')]
587 l += [KconfigCheck('cut_attack_surface', 'clipos', 'MAGIC_SYSRQ', 'is not set')]
588 l += [KconfigCheck('cut_attack_surface', 'clipos', 'KEXEC_FILE', 'is not set')] # refers to LOCKDOWN (permissive)
589 l += [KconfigCheck('cut_attack_surface', 'clipos', 'USER_NS', 'is not set')] # user.max_user_namespaces=0
590 l += [KconfigCheck('cut_attack_surface', 'clipos', 'X86_MSR', 'is not set')] # refers to LOCKDOWN
591 l += [KconfigCheck('cut_attack_surface', 'clipos', 'X86_CPUID', 'is not set')]
592 l += [KconfigCheck('cut_attack_surface', 'clipos', 'X86_IOPL_IOPERM', 'is not set')] # refers to LOCKDOWN
593 l += [KconfigCheck('cut_attack_surface', 'clipos', 'ACPI_TABLE_UPGRADE', 'is not set')] # refers to LOCKDOWN
594 l += [KconfigCheck('cut_attack_surface', 'clipos', 'EFI_CUSTOM_SSDT_OVERLAYS', 'is not set')]
595 l += [AND(KconfigCheck('cut_attack_surface', 'clipos', 'LDISC_AUTOLOAD', 'is not set'),
596 KconfigCheck('cut_attack_surface', 'clipos', 'LDISC_AUTOLOAD'))] # option presence check
597 if arch in ('X86_64', 'X86_32'):
598 l += [KconfigCheck('cut_attack_surface', 'clipos', 'X86_INTEL_TSX_MODE_OFF', 'y')] # tsx=off
600 # 'cut_attack_surface', 'lockdown'
601 l += [bpf_syscall_not_set] # refers to LOCKDOWN
602 l += [KconfigCheck('cut_attack_surface', 'lockdown', 'EFI_TEST', 'is not set')] # refers to LOCKDOWN
603 l += [KconfigCheck('cut_attack_surface', 'lockdown', 'MMIOTRACE_TEST', 'is not set')] # refers to LOCKDOWN
604 l += [KconfigCheck('cut_attack_surface', 'lockdown', 'KPROBES', 'is not set')] # refers to LOCKDOWN
606 # 'cut_attack_surface', 'my'
607 l += [OR(KconfigCheck('cut_attack_surface', 'my', 'TRIM_UNUSED_KSYMS', 'y'),
609 l += [KconfigCheck('cut_attack_surface', 'my', 'MMIOTRACE', 'is not set')] # refers to LOCKDOWN (permissive)
610 l += [KconfigCheck('cut_attack_surface', 'my', 'LIVEPATCH', 'is not set')]
611 l += [KconfigCheck('cut_attack_surface', 'my', 'IP_DCCP', 'is not set')]
612 l += [KconfigCheck('cut_attack_surface', 'my', 'IP_SCTP', 'is not set')]
613 l += [KconfigCheck('cut_attack_surface', 'my', 'FTRACE', 'is not set')] # refers to LOCKDOWN
614 l += [KconfigCheck('cut_attack_surface', 'my', 'VIDEO_VIVID', 'is not set')]
615 l += [KconfigCheck('cut_attack_surface', 'my', 'INPUT_EVBUG', 'is not set')] # Can be used as a keylogger
618 if arch in ('X86_64', 'ARM64', 'X86_32'):
619 l += [KconfigCheck('harden_userspace', 'defconfig', 'INTEGRITY', 'y')]
621 l += [KconfigCheck('harden_userspace', 'my', 'INTEGRITY', 'y')]
623 l += [KconfigCheck('harden_userspace', 'defconfig', 'ARM64_MTE', 'y')]
624 if arch in ('ARM', 'X86_32'):
625 l += [KconfigCheck('harden_userspace', 'defconfig', 'VMSPLIT_3G', 'y')]
626 if arch in ('X86_64', 'ARM64'):
627 l += [KconfigCheck('harden_userspace', 'clipos', 'ARCH_MMAP_RND_BITS', '32')]
628 if arch in ('X86_32', 'ARM'):
629 l += [KconfigCheck('harden_userspace', 'my', 'ARCH_MMAP_RND_BITS', '16')]
631 # l += [KconfigCheck('feature_test', 'my', 'LKDTM', 'm')] # only for debugging!
634 def print_unknown_options(checklist, parsed_options):
638 if o1.type != 'complex':
639 known_options.append(o1.name)
642 if o2.type != 'complex':
643 if hasattr(o2, 'name'):
644 known_options.append(o2.name)
647 if o3.type == 'complex':
648 sys.exit('[!] ERROR: unexpected ComplexOptCheck inside {}'.format(o2.name))
649 if hasattr(o3, 'name'):
650 known_options.append(o3.name)
652 for option, value in parsed_options.items():
653 if option not in known_options:
654 print('[?] No check for option {} ({})'.format(option, value))
657 def print_checklist(mode, checklist, with_results):
661 output.append(o.json_dump(with_results))
662 print(json.dumps(output))
669 print('=' * sep_line_len)
670 print('{:^40}|{:^7}|{:^12}|{:^10}|{:^18}'.format('option name', 'type', 'desired val', 'decision', 'reason'), end='')
672 print('| {}'.format('check result'), end='')
674 print('=' * sep_line_len)
677 for opt in checklist:
679 if mode == 'show_ok':
680 if not opt.result.startswith('OK'):
682 if mode == 'show_fail':
683 if not opt.result.startswith('FAIL'):
685 opt.table_print(mode, with_results)
687 if mode == 'verbose':
688 print('-' * sep_line_len)
693 fail_count = len(list(filter(lambda opt: opt.result.startswith('FAIL'), checklist)))
695 ok_count = len(list(filter(lambda opt: opt.result.startswith('OK'), checklist)))
697 if mode == 'show_ok':
698 fail_suppressed = ' (suppressed in output)'
699 if mode == 'show_fail':
700 ok_suppressed = ' (suppressed in output)'
702 print('[+] Config check is finished: \'OK\' - {}{} / \'FAIL\' - {}{}'.format(ok_count, ok_suppressed, fail_count, fail_suppressed))
705 def populate_simple_opt_with_data(opt, data, data_type):
706 if opt.type == 'complex':
707 sys.exit('[!] ERROR: unexpected ComplexOptCheck {}: {}'.format(opt.name, vars(opt)))
708 if data_type not in TYPES_OF_CHECKS:
709 sys.exit('[!] ERROR: invalid data type "{}"'.format(data_type))
711 if data_type != opt.type:
714 if data_type == 'kconfig':
715 opt.state = data.get(opt.name, None)
716 elif data_type == 'version':
719 sys.exit('[!] ERROR: unexpected data type "{}"'.format(data_type))
722 def populate_opt_with_data(opt, data, data_type):
723 if opt.type == 'complex':
725 if o.type == 'complex':
726 # Recursion for nested ComplexOptCheck objects
727 populate_opt_with_data(o, data, data_type)
729 populate_simple_opt_with_data(o, data, data_type)
731 if opt.type != 'kconfig':
732 sys.exit('[!] ERROR: bad type "{}" for a simple check {}'.format(opt.type, opt.name))
733 populate_simple_opt_with_data(opt, data, data_type)
736 def populate_with_data(checklist, data, data_type):
737 for opt in checklist:
738 populate_opt_with_data(opt, data, data_type)
741 def perform_checks(checklist):
742 for opt in checklist:
746 def parse_kconfig_file(parsed_options, fname):
747 with open(fname, 'r') as f:
748 opt_is_on = re.compile("CONFIG_[a-zA-Z0-9_]*=[a-zA-Z0-9_\"]*")
749 opt_is_off = re.compile("# CONFIG_[a-zA-Z0-9_]* is not set")
751 for line in f.readlines():
756 if opt_is_on.match(line):
757 option, value = line.split('=', 1)
758 elif opt_is_off.match(line):
759 option, value = line[2:].split(' ', 1)
760 if value != 'is not set':
761 sys.exit('[!] ERROR: bad disabled kconfig option "{}"'.format(line))
763 if option in parsed_options:
764 sys.exit('[!] ERROR: kconfig option "{}" exists multiple times'.format(line))
767 parsed_options[option] = value
773 # - reporting about unknown kernel options in the kconfig
774 # - verbose printing of ComplexOptCheck items
775 # * json mode for printing the results in JSON format
776 report_modes = ['verbose', 'json', 'show_ok', 'show_fail']
777 supported_archs = ['X86_64', 'X86_32', 'ARM64', 'ARM']
778 parser = ArgumentParser(prog='kconfig-hardened-check',
779 description='A tool for checking the security hardening options of the Linux kernel')
780 parser.add_argument('--version', action='version', version='%(prog)s ' + __version__)
781 parser.add_argument('-p', '--print', choices=supported_archs,
782 help='print security hardening preferences for the selected architecture')
783 parser.add_argument('-c', '--config',
784 help='check the kernel kconfig file against these preferences')
785 parser.add_argument('-m', '--mode', choices=report_modes,
786 help='choose the report mode')
787 args = parser.parse_args()
793 print('[+] Special report mode: {}'.format(mode))
795 config_checklist = []
799 print('[+] Kconfig file to check: {}'.format(args.config))
801 arch, msg = detect_arch(args.config, supported_archs)
803 sys.exit('[!] ERROR: {}'.format(msg))
805 print('[+] Detected architecture: {}'.format(arch))
807 kernel_version, msg = detect_version(args.config)
808 if not kernel_version:
809 sys.exit('[!] ERROR: {}'.format(msg))
811 print('[+] Detected kernel version: {}.{}'.format(kernel_version[0], kernel_version[1]))
813 # add relevant kconfig checks to the checklist
814 add_kconfig_checks(config_checklist, arch)
816 # populate the checklist with the parsed kconfig data
817 parsed_kconfig_options = OrderedDict()
818 parse_kconfig_file(parsed_kconfig_options, args.config)
819 populate_with_data(config_checklist, parsed_kconfig_options, 'kconfig')
820 populate_with_data(config_checklist, kernel_version, 'version')
822 # now everything is ready for performing the checks
823 perform_checks(config_checklist)
825 # finally print the results
826 if mode == 'verbose':
827 print_unknown_options(config_checklist, parsed_kconfig_options)
828 print_checklist(mode, config_checklist, True)
833 if mode in ('show_ok', 'show_fail'):
834 sys.exit('[!] ERROR: wrong mode "{}" for --print'.format(mode))
836 add_kconfig_checks(config_checklist, arch)
838 print('[+] Printing kernel security hardening preferences for {}...'.format(arch))
839 print_checklist(mode, config_checklist, False)
845 if __name__ == '__main__':