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'):
110 class KconfigCheck(OptCheck):
115 def table_print(self, _mode, with_results):
116 print('CONFIG_{:<33}|{:^7}|{:^12}|{:^10}|{:^18}'.format(self.name, self.type, self.expected, self.decision, self.reason), end='')
118 print('| {}'.format(self.result), end='')
122 def __init__(self, ver_expected):
123 self.ver_expected = ver_expected
128 if self.ver[0] > self.ver_expected[0]:
129 self.result = 'OK: version >= ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
131 if self.ver[0] < self.ver_expected[0]:
132 self.result = 'FAIL: version < ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
134 if self.ver[1] >= self.ver_expected[1]:
135 self.result = 'OK: version >= ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
137 self.result = 'FAIL: version < ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
140 def table_print(self, _mode, with_results):
141 ver_req = 'kernel version >= ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
142 print('{:<91}'.format(ver_req), end='')
144 print('| {}'.format(self.result), end='')
148 def __init__(self, name):
154 if self.state is None:
155 self.result = 'FAIL: not present'
157 self.result = 'OK: is present'
160 def table_print(self, _mode, with_results):
161 print('CONFIG_{:<84}'.format(self.name + ' is present'), end='')
163 print('| {}'.format(self.result), end='')
166 class ComplexOptCheck:
167 def __init__(self, *opts):
170 sys.exit('[!] ERROR: empty {} check'.format(self.__class__.__name__))
171 if not isinstance(opts[0], KconfigCheck):
172 sys.exit('[!] ERROR: invalid {} check: {}'.format(self.__class__.__name__, opts))
177 return self.opts[0].name
181 return self.opts[0].type
185 return self.opts[0].expected
189 return self.opts[0].decision
193 return self.opts[0].reason
195 def table_print(self, mode, with_results):
196 if mode == 'verbose':
197 print(' {:87}'.format('<<< ' + self.__class__.__name__ + ' >>>'), end='')
199 print('| {}'.format(self.result), end='')
202 o.table_print(mode, with_results)
205 o.table_print(mode, False)
207 print('| {}'.format(self.result), end='')
210 class OR(ComplexOptCheck):
211 # self.opts[0] is the option that this OR-check is about.
213 # OR(<X_is_hardened>, <X_is_disabled>)
214 # OR(<X_is_hardened>, <old_X_is_hardened>)
218 sys.exit('[!] ERROR: invalid OR check')
220 for i, opt in enumerate(self.opts):
223 if opt.result == 'OK' and i != 0:
224 # Simple OK is not enough for additional checks, add more info:
225 self.result = 'OK: CONFIG_{} "{}"'.format(opt.name, opt.expected)
227 self.result = opt.result
229 self.result = self.opts[0].result
233 class AND(ComplexOptCheck):
234 # self.opts[0] is the option that this AND-check is about.
236 # AND(<suboption>, <main_option>)
237 # Suboption is not checked if checking of the main_option is failed.
238 # AND(<X_is_disabled>, <old_X_is_disabled>)
241 for i, opt in reversed(list(enumerate(self.opts))):
244 self.result = opt.result
247 # This FAIL is caused by additional checks,
248 # and not by the main option that this AND-check is about.
249 # Describe the reason of the FAIL.
250 if opt.result.startswith('FAIL: \"') or opt.result == 'FAIL: not found':
251 self.result = 'FAIL: CONFIG_{} not "{}"'.format(opt.name, opt.expected)
252 elif opt.result == 'FAIL: not present':
253 self.result = 'FAIL: CONFIG_{} not present'.format(opt.name)
255 # This FAIL message is self-explaining.
256 self.result = opt.result
259 sys.exit('[!] ERROR: invalid AND check')
262 def detect_arch(fname, archs):
263 with open(fname, 'r') as f:
264 arch_pattern = re.compile("CONFIG_[a-zA-Z0-9_]*=y")
266 for line in f.readlines():
267 if arch_pattern.match(line):
268 option, _ = line[7:].split('=', 1)
273 return None, 'more than one supported architecture is detected'
275 return None, 'failed to detect architecture'
279 def detect_version(fname):
280 with open(fname, 'r') as f:
281 ver_pattern = re.compile("# Linux/.* Kernel Configuration")
282 for line in f.readlines():
283 if ver_pattern.match(line):
287 ver_numbers = ver_str.split('.')
288 if len(ver_numbers) < 3 or not ver_numbers[0].isdigit() or not ver_numbers[1].isdigit():
289 msg = 'failed to parse the version "' + ver_str + '"'
291 return (int(ver_numbers[0]), int(ver_numbers[1])), None
292 return None, 'no kernel version detected'
295 def add_kconfig_checks(l, arch):
296 # Calling the KconfigCheck class constructor:
297 # KconfigCheck(reason, decision, name, expected)
299 modules_not_set = KconfigCheck('cut_attack_surface', 'kspp', 'MODULES', 'is not set')
300 devmem_not_set = KconfigCheck('cut_attack_surface', 'kspp', 'DEVMEM', 'is not set') # refers to LOCKDOWN
302 # 'self_protection', 'defconfig'
303 l += [KconfigCheck('self_protection', 'defconfig', 'BUG', 'y')]
304 l += [KconfigCheck('self_protection', 'defconfig', 'SLUB_DEBUG', 'y')]
305 l += [KconfigCheck('self_protection', 'defconfig', 'GCC_PLUGINS', 'y')]
306 l += [OR(KconfigCheck('self_protection', 'defconfig', 'STACKPROTECTOR_STRONG', 'y'),
307 KconfigCheck('self_protection', 'defconfig', 'CC_STACKPROTECTOR_STRONG', 'y'))]
308 l += [OR(KconfigCheck('self_protection', 'defconfig', 'STRICT_KERNEL_RWX', 'y'),
309 KconfigCheck('self_protection', 'defconfig', 'DEBUG_RODATA', 'y'))] # before v4.11
310 l += [OR(KconfigCheck('self_protection', 'defconfig', 'STRICT_MODULE_RWX', 'y'),
311 KconfigCheck('self_protection', 'defconfig', 'DEBUG_SET_MODULE_RONX', 'y'),
312 modules_not_set)] # DEBUG_SET_MODULE_RONX was before v4.11
313 l += [OR(KconfigCheck('self_protection', 'defconfig', 'REFCOUNT_FULL', 'y'),
314 VerCheck((5, 5)))] # REFCOUNT_FULL is enabled by default since v5.5
315 iommu_support_is_set = KconfigCheck('self_protection', 'defconfig', 'IOMMU_SUPPORT', 'y')
316 l += [iommu_support_is_set] # is needed for mitigating DMA attacks
317 if arch in ('X86_64', 'ARM64', 'X86_32'):
318 l += [KconfigCheck('self_protection', 'defconfig', 'RANDOMIZE_BASE', 'y')]
319 l += [KconfigCheck('self_protection', 'defconfig', 'THREAD_INFO_IN_TASK', 'y')]
320 if arch in ('X86_64', 'ARM64'):
321 l += [KconfigCheck('self_protection', 'defconfig', 'VMAP_STACK', 'y')]
322 if arch in ('X86_64', 'X86_32'):
323 l += [KconfigCheck('self_protection', 'defconfig', 'MICROCODE', 'y')] # is needed for mitigating CPU bugs
324 l += [KconfigCheck('self_protection', 'defconfig', 'RETPOLINE', 'y')]
325 l += [KconfigCheck('self_protection', 'defconfig', 'X86_SMAP', 'y')]
326 l += [KconfigCheck('self_protection', 'defconfig', 'SYN_COOKIES', 'y')] # another reason?
327 l += [OR(KconfigCheck('self_protection', 'defconfig', 'X86_UMIP', 'y'),
328 KconfigCheck('self_protection', 'defconfig', 'X86_INTEL_UMIP', 'y'))]
329 if arch in ('ARM64', 'ARM'):
330 l += [KconfigCheck('self_protection', 'defconfig', 'STACKPROTECTOR_PER_TASK', 'y')]
332 l += [KconfigCheck('self_protection', 'defconfig', 'PAGE_TABLE_ISOLATION', 'y')]
333 l += [KconfigCheck('self_protection', 'defconfig', 'RANDOMIZE_MEMORY', 'y')]
334 l += [AND(KconfigCheck('self_protection', 'defconfig', 'INTEL_IOMMU', 'y'),
335 iommu_support_is_set)]
336 l += [AND(KconfigCheck('self_protection', 'defconfig', 'AMD_IOMMU', 'y'),
337 iommu_support_is_set)]
339 l += [KconfigCheck('self_protection', 'defconfig', 'ARM64_PAN', 'y')]
340 l += [KconfigCheck('self_protection', 'defconfig', 'ARM64_EPAN', 'y')]
341 l += [KconfigCheck('self_protection', 'defconfig', 'UNMAP_KERNEL_AT_EL0', 'y')]
342 l += [OR(KconfigCheck('self_protection', 'defconfig', 'HARDEN_EL2_VECTORS', 'y'),
343 AND(KconfigCheck('self_protection', 'defconfig', 'RANDOMIZE_BASE', 'y'),
344 VerCheck((5, 9))))] # HARDEN_EL2_VECTORS was included in RANDOMIZE_BASE in v5.9
345 l += [KconfigCheck('self_protection', 'defconfig', 'RODATA_FULL_DEFAULT_ENABLED', 'y')]
346 l += [KconfigCheck('self_protection', 'defconfig', 'ARM64_PTR_AUTH_KERNEL', 'y')]
347 l += [KconfigCheck('self_protection', 'defconfig', 'ARM64_BTI_KERNEL', 'y')]
348 l += [OR(KconfigCheck('self_protection', 'defconfig', 'HARDEN_BRANCH_PREDICTOR', 'y'),
349 VerCheck((5, 10)))] # HARDEN_BRANCH_PREDICTOR is enabled by default since v5.10
350 l += [KconfigCheck('self_protection', 'defconfig', 'ARM64_MTE', 'y')]
352 l += [KconfigCheck('self_protection', 'defconfig', 'CPU_SW_DOMAIN_PAN', 'y')]
353 l += [KconfigCheck('self_protection', 'defconfig', 'HARDEN_BRANCH_PREDICTOR', 'y')]
355 # 'self_protection', 'kspp'
356 l += [KconfigCheck('self_protection', 'kspp', 'SECURITY_DMESG_RESTRICT', 'y')]
357 l += [KconfigCheck('self_protection', 'kspp', 'BUG_ON_DATA_CORRUPTION', 'y')]
358 l += [KconfigCheck('self_protection', 'kspp', 'DEBUG_WX', 'y')]
359 l += [KconfigCheck('self_protection', 'kspp', 'SCHED_STACK_END_CHECK', 'y')]
360 l += [KconfigCheck('self_protection', 'kspp', 'SLAB_FREELIST_HARDENED', 'y')]
361 l += [KconfigCheck('self_protection', 'kspp', 'SLAB_FREELIST_RANDOM', 'y')]
362 l += [KconfigCheck('self_protection', 'kspp', 'SHUFFLE_PAGE_ALLOCATOR', 'y')]
363 l += [KconfigCheck('self_protection', 'kspp', 'FORTIFY_SOURCE', 'y')]
364 l += [KconfigCheck('self_protection', 'kspp', 'DEBUG_LIST', 'y')]
365 l += [KconfigCheck('self_protection', 'kspp', 'DEBUG_SG', 'y')]
366 l += [KconfigCheck('self_protection', 'kspp', 'DEBUG_CREDENTIALS', 'y')]
367 l += [KconfigCheck('self_protection', 'kspp', 'DEBUG_NOTIFIERS', 'y')]
368 l += [KconfigCheck('self_protection', 'kspp', 'INIT_ON_ALLOC_DEFAULT_ON', 'y')]
369 l += [KconfigCheck('self_protection', 'kspp', 'GCC_PLUGIN_LATENT_ENTROPY', 'y')]
370 randstruct_is_set = KconfigCheck('self_protection', 'kspp', 'GCC_PLUGIN_RANDSTRUCT', 'y')
371 l += [randstruct_is_set]
372 hardened_usercopy_is_set = KconfigCheck('self_protection', 'kspp', 'HARDENED_USERCOPY', 'y')
373 l += [hardened_usercopy_is_set]
374 l += [AND(KconfigCheck('self_protection', 'kspp', 'HARDENED_USERCOPY_FALLBACK', 'is not set'),
375 hardened_usercopy_is_set)]
376 l += [AND(KconfigCheck('self_protection', 'kspp', 'HARDENED_USERCOPY_PAGESPAN', 'is not set'),
377 hardened_usercopy_is_set)]
378 l += [OR(KconfigCheck('self_protection', 'kspp', 'MODULE_SIG', 'y'),
380 l += [OR(KconfigCheck('self_protection', 'kspp', 'MODULE_SIG_ALL', 'y'),
382 l += [OR(KconfigCheck('self_protection', 'kspp', 'MODULE_SIG_SHA512', 'y'),
384 l += [OR(KconfigCheck('self_protection', 'kspp', 'MODULE_SIG_FORCE', 'y'),
385 modules_not_set)] # refers to LOCKDOWN
386 l += [OR(KconfigCheck('self_protection', 'kspp', 'INIT_STACK_ALL_ZERO', 'y'),
387 KconfigCheck('self_protection', 'kspp', 'GCC_PLUGIN_STRUCTLEAK_BYREF_ALL', 'y'))]
388 l += [OR(KconfigCheck('self_protection', 'kspp', 'INIT_ON_FREE_DEFAULT_ON', 'y'),
389 KconfigCheck('self_protection', 'kspp', 'PAGE_POISONING_ZERO', 'y'))]
390 # CONFIG_INIT_ON_FREE_DEFAULT_ON was added in v5.3.
391 # CONFIG_PAGE_POISONING_ZERO was removed in v5.11.
392 # Starting from v5.11 CONFIG_PAGE_POISONING unconditionally checks
393 # the 0xAA poison pattern on allocation.
394 # That brings higher performance penalty.
395 if arch in ('X86_64', 'ARM64', 'X86_32'):
396 stackleak_is_set = KconfigCheck('self_protection', 'kspp', 'GCC_PLUGIN_STACKLEAK', 'y')
397 l += [stackleak_is_set]
398 l += [KconfigCheck('self_protection', 'kspp', 'RANDOMIZE_KSTACK_OFFSET_DEFAULT', 'y')]
399 if arch in ('X86_64', 'X86_32'):
400 l += [KconfigCheck('self_protection', 'kspp', 'DEFAULT_MMAP_MIN_ADDR', '65536')]
401 if arch in ('ARM64', 'ARM'):
402 l += [KconfigCheck('self_protection', 'kspp', 'DEFAULT_MMAP_MIN_ADDR', '32768')]
403 l += [KconfigCheck('self_protection', 'kspp', 'SYN_COOKIES', 'y')] # another reason?
405 l += [KconfigCheck('self_protection', 'kspp', 'ARM64_SW_TTBR0_PAN', 'y')]
407 l += [KconfigCheck('self_protection', 'kspp', 'PAGE_TABLE_ISOLATION', 'y')]
408 l += [KconfigCheck('self_protection', 'kspp', 'HIGHMEM64G', 'y')]
409 l += [KconfigCheck('self_protection', 'kspp', 'X86_PAE', 'y')]
411 # 'self_protection', 'maintainer'
412 ubsan_bounds_is_set = KconfigCheck('self_protection', 'maintainer', 'UBSAN_BOUNDS', 'y') # only array index bounds checking
413 l += [ubsan_bounds_is_set] # recommended by Kees Cook in /issues/53
414 l += [AND(KconfigCheck('self_protection', 'maintainer', 'UBSAN_SANITIZE_ALL', 'y'),
415 ubsan_bounds_is_set)] # recommended by Kees Cook in /issues/53
416 l += [AND(KconfigCheck('self_protection', 'maintainer', 'UBSAN_TRAP', 'y'),
417 ubsan_bounds_is_set)] # recommended by Kees Cook in /issues/53
419 # 'self_protection', 'clipos'
420 l += [KconfigCheck('self_protection', 'clipos', 'DEBUG_VIRTUAL', 'y')]
421 l += [KconfigCheck('self_protection', 'clipos', 'STATIC_USERMODEHELPER', 'y')] # needs userspace support
422 l += [KconfigCheck('self_protection', 'clipos', 'EFI_DISABLE_PCI_DMA', 'y')]
423 l += [KconfigCheck('self_protection', 'clipos', 'SLAB_MERGE_DEFAULT', 'is not set')] # slab_nomerge
424 l += [KconfigCheck('self_protection', 'clipos', 'RANDOM_TRUST_BOOTLOADER', 'is not set')]
425 l += [KconfigCheck('self_protection', 'clipos', 'RANDOM_TRUST_CPU', 'is not set')]
426 l += [AND(KconfigCheck('self_protection', 'clipos', 'GCC_PLUGIN_RANDSTRUCT_PERFORMANCE', 'is not set'),
428 if arch in ('X86_64', 'ARM64', 'X86_32'):
429 l += [AND(KconfigCheck('self_protection', 'clipos', 'STACKLEAK_METRICS', 'is not set'),
431 l += [AND(KconfigCheck('self_protection', 'clipos', 'STACKLEAK_RUNTIME_DISABLE', 'is not set'),
433 if arch in ('X86_64', 'X86_32'):
434 l += [AND(KconfigCheck('self_protection', 'clipos', 'INTEL_IOMMU_DEFAULT_ON', 'y'),
435 iommu_support_is_set)]
437 l += [AND(KconfigCheck('self_protection', 'clipos', 'INTEL_IOMMU_SVM', 'y'),
438 iommu_support_is_set)]
440 l += [AND(KconfigCheck('self_protection', 'clipos', 'INTEL_IOMMU', 'y'),
441 iommu_support_is_set)]
443 # 'self_protection', 'my'
444 l += [KconfigCheck('self_protection', 'my', 'RESET_ATTACK_MITIGATION', 'y')] # needs userspace support (systemd)
446 l += [AND(KconfigCheck('self_protection', 'my', 'AMD_IOMMU_V2', 'y'),
447 iommu_support_is_set)]
449 l += [KconfigCheck('self_protection', 'my', 'SHADOW_CALL_STACK', 'y')] # depends on clang, maybe it's alternative to STACKPROTECTOR_STRONG
450 l += [KconfigCheck('self_protection', 'my', 'KASAN_HW_TAGS', 'y')]
451 cfi_clang_is_set = KconfigCheck('self_protection', 'my', 'CFI_CLANG', 'y')
452 l += [cfi_clang_is_set]
453 l += [AND(KconfigCheck('self_protection', 'my', 'CFI_PERMISSIVE', 'is not set'),
457 if arch in ('X86_64', 'ARM64', 'X86_32'):
458 l += [KconfigCheck('security_policy', 'defconfig', 'SECURITY', 'y')] # and choose your favourite LSM
460 l += [KconfigCheck('security_policy', 'kspp', 'SECURITY', 'y')] # and choose your favourite LSM
461 l += [KconfigCheck('security_policy', 'kspp', 'SECURITY_YAMA', 'y')]
462 l += [OR(KconfigCheck('security_policy', 'my', 'SECURITY_WRITABLE_HOOKS', 'is not set'),
463 KconfigCheck('security_policy', 'kspp', 'SECURITY_SELINUX_DISABLE', 'is not set'))]
464 l += [KconfigCheck('security_policy', 'clipos', 'SECURITY_LOCKDOWN_LSM', 'y')]
465 l += [KconfigCheck('security_policy', 'clipos', 'SECURITY_LOCKDOWN_LSM_EARLY', 'y')]
466 l += [KconfigCheck('security_policy', 'clipos', 'LOCK_DOWN_KERNEL_FORCE_CONFIDENTIALITY', 'y')]
467 l += [KconfigCheck('security_policy', 'my', 'SECURITY_SAFESETID', 'y')]
468 loadpin_is_set = KconfigCheck('security_policy', 'my', 'SECURITY_LOADPIN', 'y')
469 l += [loadpin_is_set] # needs userspace support
470 l += [AND(KconfigCheck('security_policy', 'my', 'SECURITY_LOADPIN_ENFORCE', 'y'),
473 # 'cut_attack_surface', 'defconfig'
474 l += [KconfigCheck('cut_attack_surface', 'defconfig', 'SECCOMP', 'y')]
475 l += [KconfigCheck('cut_attack_surface', 'defconfig', 'SECCOMP_FILTER', 'y')]
476 if arch in ('X86_64', 'ARM64', 'X86_32'):
477 l += [OR(KconfigCheck('cut_attack_surface', 'defconfig', 'STRICT_DEVMEM', 'y'),
478 devmem_not_set)] # refers to LOCKDOWN
480 # 'cut_attack_surface', 'kspp'
481 l += [KconfigCheck('cut_attack_surface', 'kspp', 'ACPI_CUSTOM_METHOD', 'is not set')] # refers to LOCKDOWN
482 l += [KconfigCheck('cut_attack_surface', 'kspp', 'COMPAT_BRK', 'is not set')]
483 l += [KconfigCheck('cut_attack_surface', 'kspp', 'DEVKMEM', 'is not set')] # refers to LOCKDOWN
484 l += [KconfigCheck('cut_attack_surface', 'kspp', 'COMPAT_VDSO', 'is not set')]
485 l += [KconfigCheck('cut_attack_surface', 'kspp', 'BINFMT_MISC', 'is not set')]
486 l += [KconfigCheck('cut_attack_surface', 'kspp', 'INET_DIAG', 'is not set')]
487 l += [KconfigCheck('cut_attack_surface', 'kspp', 'KEXEC', 'is not set')] # refers to LOCKDOWN
488 l += [KconfigCheck('cut_attack_surface', 'kspp', 'PROC_KCORE', 'is not set')] # refers to LOCKDOWN
489 l += [KconfigCheck('cut_attack_surface', 'kspp', 'LEGACY_PTYS', 'is not set')]
490 l += [KconfigCheck('cut_attack_surface', 'kspp', 'HIBERNATION', 'is not set')] # refers to LOCKDOWN
491 l += [KconfigCheck('cut_attack_surface', 'kspp', 'IA32_EMULATION', 'is not set')]
492 l += [KconfigCheck('cut_attack_surface', 'kspp', 'X86_X32', 'is not set')]
493 l += [KconfigCheck('cut_attack_surface', 'kspp', 'MODIFY_LDT_SYSCALL', 'is not set')]
494 l += [KconfigCheck('cut_attack_surface', 'kspp', 'OABI_COMPAT', 'is not set')]
495 l += [modules_not_set]
496 l += [devmem_not_set]
497 l += [OR(KconfigCheck('cut_attack_surface', 'kspp', 'IO_STRICT_DEVMEM', 'y'),
498 devmem_not_set)] # refers to LOCKDOWN
500 l += [OR(KconfigCheck('cut_attack_surface', 'kspp', 'STRICT_DEVMEM', 'y'),
501 devmem_not_set)] # refers to LOCKDOWN
503 l += [KconfigCheck('cut_attack_surface', 'kspp', 'LEGACY_VSYSCALL_NONE', 'y')] # 'vsyscall=none'
505 # 'cut_attack_surface', 'grsec'
506 l += [KconfigCheck('cut_attack_surface', 'grsec', 'ZSMALLOC_STAT', 'is not set')]
507 l += [KconfigCheck('cut_attack_surface', 'grsec', 'PAGE_OWNER', 'is not set')]
508 l += [KconfigCheck('cut_attack_surface', 'grsec', 'DEBUG_KMEMLEAK', 'is not set')]
509 l += [KconfigCheck('cut_attack_surface', 'grsec', 'BINFMT_AOUT', 'is not set')]
510 l += [KconfigCheck('cut_attack_surface', 'grsec', 'KPROBE_EVENTS', 'is not set')]
511 l += [KconfigCheck('cut_attack_surface', 'grsec', 'UPROBE_EVENTS', 'is not set')]
512 l += [KconfigCheck('cut_attack_surface', 'grsec', 'GENERIC_TRACER', 'is not set')] # refers to LOCKDOWN
513 l += [KconfigCheck('cut_attack_surface', 'grsec', 'FUNCTION_TRACER', 'is not set')]
514 l += [KconfigCheck('cut_attack_surface', 'grsec', 'STACK_TRACER', 'is not set')]
515 l += [KconfigCheck('cut_attack_surface', 'grsec', 'HIST_TRIGGERS', 'is not set')]
516 l += [KconfigCheck('cut_attack_surface', 'grsec', 'BLK_DEV_IO_TRACE', 'is not set')]
517 l += [KconfigCheck('cut_attack_surface', 'grsec', 'PROC_VMCORE', 'is not set')]
518 l += [KconfigCheck('cut_attack_surface', 'grsec', 'PROC_PAGE_MONITOR', 'is not set')]
519 l += [KconfigCheck('cut_attack_surface', 'grsec', 'USELIB', 'is not set')]
520 l += [KconfigCheck('cut_attack_surface', 'grsec', 'CHECKPOINT_RESTORE', 'is not set')]
521 l += [KconfigCheck('cut_attack_surface', 'grsec', 'USERFAULTFD', 'is not set')]
522 l += [KconfigCheck('cut_attack_surface', 'grsec', 'HWPOISON_INJECT', 'is not set')]
523 l += [KconfigCheck('cut_attack_surface', 'grsec', 'MEM_SOFT_DIRTY', 'is not set')]
524 l += [KconfigCheck('cut_attack_surface', 'grsec', 'DEVPORT', 'is not set')] # refers to LOCKDOWN
525 l += [KconfigCheck('cut_attack_surface', 'grsec', 'DEBUG_FS', 'is not set')] # refers to LOCKDOWN
526 l += [KconfigCheck('cut_attack_surface', 'grsec', 'NOTIFIER_ERROR_INJECTION', 'is not set')]
527 l += [KconfigCheck('cut_attack_surface', 'grsec', 'FAIL_FUTEX', 'is not set')]
528 l += [KconfigCheck('cut_attack_surface', 'grsec', 'PUNIT_ATOM_DEBUG', 'is not set')]
529 l += [KconfigCheck('cut_attack_surface', 'grsec', 'ACPI_CONFIGFS', 'is not set')]
530 l += [KconfigCheck('cut_attack_surface', 'grsec', 'EDAC_DEBUG', 'is not set')]
531 l += [KconfigCheck('cut_attack_surface', 'grsec', 'DRM_I915_DEBUG', 'is not set')]
532 l += [KconfigCheck('cut_attack_surface', 'grsec', 'BCACHE_CLOSURES_DEBUG', 'is not set')]
533 l += [KconfigCheck('cut_attack_surface', 'grsec', 'DVB_C8SECTPFE', 'is not set')]
534 l += [KconfigCheck('cut_attack_surface', 'grsec', 'MTD_SLRAM', 'is not set')]
535 l += [KconfigCheck('cut_attack_surface', 'grsec', 'MTD_PHRAM', 'is not set')]
536 l += [KconfigCheck('cut_attack_surface', 'grsec', 'IO_URING', 'is not set')]
537 l += [KconfigCheck('cut_attack_surface', 'grsec', 'KCMP', 'is not set')]
538 l += [KconfigCheck('cut_attack_surface', 'grsec', 'RSEQ', 'is not set')]
539 l += [KconfigCheck('cut_attack_surface', 'grsec', 'LATENCYTOP', 'is not set')]
540 l += [KconfigCheck('cut_attack_surface', 'grsec', 'KCOV', 'is not set')]
541 l += [KconfigCheck('cut_attack_surface', 'grsec', 'PROVIDE_OHCI1394_DMA_INIT', 'is not set')]
542 l += [KconfigCheck('cut_attack_surface', 'grsec', 'SUNRPC_DEBUG', 'is not set')]
543 l += [AND(KconfigCheck('cut_attack_surface', 'grsec', 'PTDUMP_DEBUGFS', 'is not set'),
544 KconfigCheck('cut_attack_surface', 'grsec', 'X86_PTDUMP', 'is not set'))]
546 # 'cut_attack_surface', 'maintainer'
547 l += [KconfigCheck('cut_attack_surface', 'maintainer', 'DRM_LEGACY', 'is not set')] # recommended by Daniel Vetter in /issues/38
548 l += [KconfigCheck('cut_attack_surface', 'maintainer', 'FB', 'is not set')] # recommended by Daniel Vetter in /issues/38
549 l += [KconfigCheck('cut_attack_surface', 'maintainer', 'VT', 'is not set')] # recommended by Daniel Vetter in /issues/38
550 l += [KconfigCheck('cut_attack_surface', 'maintainer', 'BLK_DEV_FD', 'is not set')] # recommended by Denis Efremov in /pull/54
552 # 'cut_attack_surface', 'grapheneos'
553 l += [KconfigCheck('cut_attack_surface', 'grapheneos', 'AIO', 'is not set')]
555 # 'cut_attack_surface', 'clipos'
556 l += [KconfigCheck('cut_attack_surface', 'clipos', 'STAGING', 'is not set')]
557 l += [KconfigCheck('cut_attack_surface', 'clipos', 'KSM', 'is not set')] # to prevent FLUSH+RELOAD attack
558 # l += [KconfigCheck('cut_attack_surface', 'clipos', 'IKCONFIG', 'is not set')] # no, IKCONFIG is needed for this check :)
559 l += [KconfigCheck('cut_attack_surface', 'clipos', 'KALLSYMS', 'is not set')]
560 l += [KconfigCheck('cut_attack_surface', 'clipos', 'X86_VSYSCALL_EMULATION', 'is not set')]
561 l += [KconfigCheck('cut_attack_surface', 'clipos', 'MAGIC_SYSRQ', 'is not set')]
562 l += [KconfigCheck('cut_attack_surface', 'clipos', 'KEXEC_FILE', 'is not set')] # refers to LOCKDOWN (permissive)
563 l += [KconfigCheck('cut_attack_surface', 'clipos', 'USER_NS', 'is not set')] # user.max_user_namespaces=0
564 l += [KconfigCheck('cut_attack_surface', 'clipos', 'X86_MSR', 'is not set')] # refers to LOCKDOWN
565 l += [KconfigCheck('cut_attack_surface', 'clipos', 'X86_CPUID', 'is not set')]
566 l += [KconfigCheck('cut_attack_surface', 'clipos', 'X86_IOPL_IOPERM', 'is not set')] # refers to LOCKDOWN
567 l += [KconfigCheck('cut_attack_surface', 'clipos', 'ACPI_TABLE_UPGRADE', 'is not set')] # refers to LOCKDOWN
568 l += [KconfigCheck('cut_attack_surface', 'clipos', 'EFI_CUSTOM_SSDT_OVERLAYS', 'is not set')]
569 l += [AND(KconfigCheck('cut_attack_surface', 'clipos', 'LDISC_AUTOLOAD', 'is not set'),
570 PresenceCheck('LDISC_AUTOLOAD'))]
571 if arch in ('X86_64', 'X86_32'):
572 l += [KconfigCheck('cut_attack_surface', 'clipos', 'X86_INTEL_TSX_MODE_OFF', 'y')] # tsx=off
574 # 'cut_attack_surface', 'lockdown'
575 l += [KconfigCheck('cut_attack_surface', 'lockdown', 'EFI_TEST', 'is not set')] # refers to LOCKDOWN
576 l += [KconfigCheck('cut_attack_surface', 'lockdown', 'BPF_SYSCALL', 'is not set')] # refers to LOCKDOWN
577 l += [KconfigCheck('cut_attack_surface', 'lockdown', 'MMIOTRACE_TEST', 'is not set')] # refers to LOCKDOWN
578 l += [KconfigCheck('cut_attack_surface', 'lockdown', 'KPROBES', 'is not set')] # refers to LOCKDOWN
580 # 'cut_attack_surface', 'my'
581 l += [OR(KconfigCheck('cut_attack_surface', 'my', 'TRIM_UNUSED_KSYMS', 'y'),
583 l += [KconfigCheck('cut_attack_surface', 'my', 'MMIOTRACE', 'is not set')] # refers to LOCKDOWN (permissive)
584 l += [KconfigCheck('cut_attack_surface', 'my', 'LIVEPATCH', 'is not set')]
585 l += [KconfigCheck('cut_attack_surface', 'my', 'IP_DCCP', 'is not set')]
586 l += [KconfigCheck('cut_attack_surface', 'my', 'IP_SCTP', 'is not set')]
587 l += [KconfigCheck('cut_attack_surface', 'my', 'FTRACE', 'is not set')] # refers to LOCKDOWN
588 l += [KconfigCheck('cut_attack_surface', 'my', 'VIDEO_VIVID', 'is not set')]
589 l += [KconfigCheck('cut_attack_surface', 'my', 'INPUT_EVBUG', 'is not set')] # Can be used as a keylogger
592 if arch in ('X86_64', 'ARM64', 'X86_32'):
593 l += [KconfigCheck('harden_userspace', 'defconfig', 'INTEGRITY', 'y')]
595 l += [KconfigCheck('harden_userspace', 'my', 'INTEGRITY', 'y')]
597 l += [KconfigCheck('harden_userspace', 'defconfig', 'ARM64_MTE', 'y')]
598 if arch in ('ARM', 'X86_32'):
599 l += [KconfigCheck('harden_userspace', 'defconfig', 'VMSPLIT_3G', 'y')]
600 if arch in ('X86_64', 'ARM64'):
601 l += [KconfigCheck('harden_userspace', 'clipos', 'ARCH_MMAP_RND_BITS', '32')]
602 if arch in ('X86_32', 'ARM'):
603 l += [KconfigCheck('harden_userspace', 'my', 'ARCH_MMAP_RND_BITS', '16')]
605 # l += [KconfigCheck('feature_test', 'my', 'LKDTM', 'm')] # only for debugging!
608 def print_unknown_options(checklist, parsed_options):
610 for opt in checklist:
611 if hasattr(opt, 'opts'):
613 if hasattr(o, 'name'):
614 known_options.append(o.name)
616 known_options.append(opt.name)
617 for option, value in parsed_options.items():
618 if option not in known_options:
619 print('[?] No rule for option {} ({})'.format(option, value))
622 def print_checklist(mode, checklist, with_results):
626 opt = ['CONFIG_'+o.name, o.type, o.expected, o.decision, o.reason]
630 print(json.dumps(opts))
637 print('=' * sep_line_len)
638 print('{:^40}|{:^7}|{:^12}|{:^10}|{:^18}'.format('option name', 'type', 'desired val', 'decision', 'reason'), end='')
640 print('| {}'.format('check result'), end='')
642 print('=' * sep_line_len)
645 for opt in checklist:
647 if mode == 'show_ok':
648 if not opt.result.startswith('OK'):
650 if mode == 'show_fail':
651 if not opt.result.startswith('FAIL'):
653 opt.table_print(mode, with_results)
655 if mode == 'verbose':
656 print('-' * sep_line_len)
661 fail_count = len(list(filter(lambda opt: opt.result.startswith('FAIL'), checklist)))
663 ok_count = len(list(filter(lambda opt: opt.result.startswith('OK'), checklist)))
665 if mode == 'show_ok':
666 fail_suppressed = ' (suppressed in output)'
667 if mode == 'show_fail':
668 ok_suppressed = ' (suppressed in output)'
670 print('[+] Config check is finished: \'OK\' - {}{} / \'FAIL\' - {}{}'.format(ok_count, ok_suppressed, fail_count, fail_suppressed))
673 def populate_opt_with_data(opt, parsed_options, kernel_version):
674 if hasattr(opt, 'opts'):
675 # prepare ComplexOptCheck
677 if hasattr(o, 'opts'):
678 # Recursion for nested ComplexOptChecks
679 populate_opt_with_data(o, parsed_options, kernel_version)
680 if hasattr(o, 'state'):
681 o.state = parsed_options.get(o.name, None)
682 if hasattr(o, 'ver'):
683 o.ver = kernel_version
685 # prepare simple check, opt.state is mandatory
686 if not hasattr(opt, 'state'):
687 sys.exit('[!] ERROR: bad simple check {}'.format(vars(opt)))
688 opt.state = parsed_options.get(opt.name, None)
691 def populate_with_data(checklist, parsed_options, kernel_version):
692 for opt in checklist:
693 populate_opt_with_data(opt, parsed_options, kernel_version)
696 def perform_checks(checklist):
697 for opt in checklist:
701 def parse_kconfig_file(parsed_options, fname):
702 with open(fname, 'r') as f:
703 opt_is_on = re.compile("CONFIG_[a-zA-Z0-9_]*=[a-zA-Z0-9_\"]*")
704 opt_is_off = re.compile("# CONFIG_[a-zA-Z0-9_]* is not set")
706 for line in f.readlines():
711 if opt_is_on.match(line):
712 option, value = line[7:].split('=', 1)
713 elif opt_is_off.match(line):
714 option, value = line[9:].split(' ', 1)
715 if value != 'is not set':
716 sys.exit('[!] ERROR: bad disabled kconfig option "{}"'.format(line))
718 if option in parsed_options:
719 sys.exit('[!] ERROR: kconfig option "{}" exists multiple times'.format(line))
722 parsed_options[option] = value
724 return parsed_options
730 # - reporting about unknown kernel options in the kconfig
731 # - verbose printing of ComplexOptCheck items
732 # * json mode for printing the results in JSON format
733 report_modes = ['verbose', 'json', 'show_ok', 'show_fail']
734 supported_archs = ['X86_64', 'X86_32', 'ARM64', 'ARM']
735 parser = ArgumentParser(prog='kconfig-hardened-check',
736 description='A tool for checking the security hardening options of the Linux kernel')
737 parser.add_argument('--version', action='version', version='%(prog)s ' + __version__)
738 parser.add_argument('-p', '--print', choices=supported_archs,
739 help='print security hardening preferences for the selected architecture')
740 parser.add_argument('-c', '--config',
741 help='check the kernel kconfig file against these preferences')
742 parser.add_argument('-m', '--mode', choices=report_modes,
743 help='choose the report mode')
744 args = parser.parse_args()
750 print("[+] Special report mode: {}".format(mode))
752 config_checklist = []
756 print('[+] Kconfig file to check: {}'.format(args.config))
758 arch, msg = detect_arch(args.config, supported_archs)
760 sys.exit('[!] ERROR: {}'.format(msg))
762 print('[+] Detected architecture: {}'.format(arch))
764 kernel_version, msg = detect_version(args.config)
765 if not kernel_version:
766 sys.exit('[!] ERROR: {}'.format(msg))
768 print('[+] Detected kernel version: {}.{}'.format(kernel_version[0], kernel_version[1]))
770 # add relevant kconfig checks to the checklist
771 add_kconfig_checks(config_checklist, arch)
773 # populate the checklist with the parsed kconfig data
774 parsed_kconfig_options = OrderedDict()
775 parse_kconfig_file(parsed_kconfig_options, args.config)
776 populate_with_data(config_checklist, parsed_kconfig_options, kernel_version)
778 # now everything is ready for performing the checks
779 perform_checks(config_checklist)
781 # finally print the results
782 if mode == 'verbose':
783 print_unknown_options(config_checklist, parsed_kconfig_options)
784 print_checklist(mode, config_checklist, True)
789 if mode in ('show_ok', 'show_fail'):
790 sys.exit('[!] ERROR: wrong mode "{}" for --print'.format(mode))
792 add_kconfig_checks(config_checklist, arch)
794 print('[+] Printing kernel security hardening preferences for {}...'.format(arch))
795 print_checklist(mode, config_checklist, False)
801 if __name__ == '__main__':