4 # This tool helps me to check the Linux kernel Kconfig option list
5 # against 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}|{:^11}|{:^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('{:<90}'.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_{:<83}'.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].expected
185 return self.opts[0].decision
189 return self.opts[0].reason
191 def table_print(self, mode, with_results):
192 if mode == 'verbose':
193 print(' {:86}'.format('<<< ' + self.__class__.__name__ + ' >>>'), end='')
195 print('| {}'.format(self.result), end='')
198 o.table_print(mode, with_results)
201 o.table_print(mode, False)
203 print('| {}'.format(self.result), end='')
206 class OR(ComplexOptCheck):
207 # self.opts[0] is the option that this OR-check is about.
209 # OR(<X_is_hardened>, <X_is_disabled>)
210 # OR(<X_is_hardened>, <old_X_is_hardened>)
214 sys.exit('[!] ERROR: invalid OR check')
216 for i, opt in enumerate(self.opts):
219 if opt.result != 'OK' or i == 0:
220 # Preserve additional explanation of this OK result.
221 # Simple OK is enough only for the main option that
222 # this OR-check is about.
223 self.result = opt.result
225 # Simple OK is not enough for additional checks.
226 self.result = 'OK: CONFIG_{} "{}"'.format(opt.name, opt.expected)
228 self.result = self.opts[0].result
232 class AND(ComplexOptCheck):
233 # self.opts[0] is the option that this AND-check is about.
235 # AND(<suboption>, <main_option>)
236 # Suboption is not checked if checking of the main_option is failed.
237 # AND(<X_is_disabled>, <old_X_is_disabled>)
240 for i, opt in reversed(list(enumerate(self.opts))):
243 self.result = opt.result
246 # This FAIL is caused by additional checks,
247 # and not by the main option that this AND-check is about.
248 # Describe the reason of the FAIL.
249 if opt.result.startswith('FAIL: \"') or opt.result == 'FAIL: not found':
250 self.result = 'FAIL: CONFIG_{} not "{}"'.format(opt.name, opt.expected)
251 elif opt.result == 'FAIL: not present':
252 self.result = 'FAIL: CONFIG_{} not present'.format(opt.name)
254 # This FAIL message is self-explaining.
255 self.result = opt.result
258 sys.exit('[!] ERROR: invalid AND check')
261 def detect_arch(fname, archs):
262 with open(fname, 'r') as f:
263 arch_pattern = re.compile("CONFIG_[a-zA-Z0-9_]*=y")
265 for line in f.readlines():
266 if arch_pattern.match(line):
267 option, _ = line[7:].split('=', 1)
272 return None, 'more than one supported architecture is detected'
274 return None, 'failed to detect architecture'
278 def detect_version(fname):
279 with open(fname, 'r') as f:
280 ver_pattern = re.compile("# Linux/.* Kernel Configuration")
281 for line in f.readlines():
282 if ver_pattern.match(line):
286 ver_numbers = ver_str.split('.')
287 if len(ver_numbers) < 3 or not ver_numbers[0].isdigit() or not ver_numbers[1].isdigit():
288 msg = 'failed to parse the version "' + ver_str + '"'
290 return (int(ver_numbers[0]), int(ver_numbers[1])), None
291 return None, 'no kernel version detected'
294 def construct_checklist(l, arch):
295 # Calling the KconfigCheck class constructor:
296 # KconfigCheck(reason, decision, name, expected)
298 modules_not_set = KconfigCheck('cut_attack_surface', 'kspp', 'MODULES', 'is not set')
299 devmem_not_set = KconfigCheck('cut_attack_surface', 'kspp', 'DEVMEM', 'is not set') # refers to LOCKDOWN
301 # 'self_protection', 'defconfig'
302 l += [KconfigCheck('self_protection', 'defconfig', 'BUG', 'y')]
303 l += [KconfigCheck('self_protection', 'defconfig', 'SLUB_DEBUG', 'y')]
304 l += [KconfigCheck('self_protection', 'defconfig', 'GCC_PLUGINS', 'y')]
305 l += [OR(KconfigCheck('self_protection', 'defconfig', 'STACKPROTECTOR_STRONG', 'y'),
306 KconfigCheck('self_protection', 'defconfig', 'CC_STACKPROTECTOR_STRONG', 'y'))]
307 l += [OR(KconfigCheck('self_protection', 'defconfig', 'STRICT_KERNEL_RWX', 'y'),
308 KconfigCheck('self_protection', 'defconfig', 'DEBUG_RODATA', 'y'))] # before v4.11
309 l += [OR(KconfigCheck('self_protection', 'defconfig', 'STRICT_MODULE_RWX', 'y'),
310 KconfigCheck('self_protection', 'defconfig', 'DEBUG_SET_MODULE_RONX', 'y'),
311 modules_not_set)] # DEBUG_SET_MODULE_RONX was before v4.11
312 l += [OR(KconfigCheck('self_protection', 'defconfig', 'REFCOUNT_FULL', 'y'),
313 VerCheck((5, 5)))] # REFCOUNT_FULL is enabled by default since v5.5
314 iommu_support_is_set = KconfigCheck('self_protection', 'defconfig', 'IOMMU_SUPPORT', 'y')
315 l += [iommu_support_is_set] # is needed for mitigating DMA attacks
316 if arch in ('X86_64', 'ARM64', 'X86_32'):
317 l += [KconfigCheck('self_protection', 'defconfig', 'RANDOMIZE_BASE', 'y')]
318 l += [KconfigCheck('self_protection', 'defconfig', 'THREAD_INFO_IN_TASK', 'y')]
319 if arch in ('X86_64', 'ARM64'):
320 l += [KconfigCheck('self_protection', 'defconfig', 'VMAP_STACK', 'y')]
321 if arch in ('X86_64', 'X86_32'):
322 l += [KconfigCheck('self_protection', 'defconfig', 'MICROCODE', 'y')] # is needed for mitigating CPU bugs
323 l += [KconfigCheck('self_protection', 'defconfig', 'RETPOLINE', 'y')]
324 l += [KconfigCheck('self_protection', 'defconfig', 'X86_SMAP', 'y')]
325 l += [KconfigCheck('self_protection', 'defconfig', 'SYN_COOKIES', 'y')] # another reason?
326 l += [OR(KconfigCheck('self_protection', 'defconfig', 'X86_UMIP', 'y'),
327 KconfigCheck('self_protection', 'defconfig', 'X86_INTEL_UMIP', 'y'))]
328 if arch in ('ARM64', 'ARM'):
329 l += [KconfigCheck('self_protection', 'defconfig', 'STACKPROTECTOR_PER_TASK', 'y')]
331 l += [KconfigCheck('self_protection', 'defconfig', 'PAGE_TABLE_ISOLATION', 'y')]
332 l += [KconfigCheck('self_protection', 'defconfig', 'RANDOMIZE_MEMORY', 'y')]
333 l += [AND(KconfigCheck('self_protection', 'defconfig', 'INTEL_IOMMU', 'y'),
334 iommu_support_is_set)]
335 l += [AND(KconfigCheck('self_protection', 'defconfig', 'AMD_IOMMU', 'y'),
336 iommu_support_is_set)]
338 l += [KconfigCheck('self_protection', 'defconfig', 'ARM64_PAN', 'y')]
339 l += [KconfigCheck('self_protection', 'defconfig', 'ARM64_EPAN', 'y')]
340 l += [KconfigCheck('self_protection', 'defconfig', 'UNMAP_KERNEL_AT_EL0', 'y')]
341 l += [OR(KconfigCheck('self_protection', 'defconfig', 'HARDEN_EL2_VECTORS', 'y'),
342 AND(KconfigCheck('self_protection', 'defconfig', 'RANDOMIZE_BASE', 'y'),
343 VerCheck((5, 9))))] # HARDEN_EL2_VECTORS was included in RANDOMIZE_BASE in v5.9
344 l += [KconfigCheck('self_protection', 'defconfig', 'RODATA_FULL_DEFAULT_ENABLED', 'y')]
345 l += [KconfigCheck('self_protection', 'defconfig', 'ARM64_PTR_AUTH_KERNEL', 'y')]
346 l += [KconfigCheck('self_protection', 'defconfig', 'ARM64_BTI_KERNEL', 'y')]
347 l += [OR(KconfigCheck('self_protection', 'defconfig', 'HARDEN_BRANCH_PREDICTOR', 'y'),
348 VerCheck((5, 10)))] # HARDEN_BRANCH_PREDICTOR is enabled by default since v5.10
349 l += [KconfigCheck('self_protection', 'defconfig', 'ARM64_MTE', 'y')]
351 l += [KconfigCheck('self_protection', 'defconfig', 'CPU_SW_DOMAIN_PAN', 'y')]
352 l += [KconfigCheck('self_protection', 'defconfig', 'HARDEN_BRANCH_PREDICTOR', 'y')]
354 # 'self_protection', 'kspp'
355 l += [KconfigCheck('self_protection', 'kspp', 'SECURITY_DMESG_RESTRICT', 'y')]
356 l += [KconfigCheck('self_protection', 'kspp', 'BUG_ON_DATA_CORRUPTION', 'y')]
357 l += [KconfigCheck('self_protection', 'kspp', 'DEBUG_WX', 'y')]
358 l += [KconfigCheck('self_protection', 'kspp', 'SCHED_STACK_END_CHECK', 'y')]
359 l += [KconfigCheck('self_protection', 'kspp', 'SLAB_FREELIST_HARDENED', 'y')]
360 l += [KconfigCheck('self_protection', 'kspp', 'SLAB_FREELIST_RANDOM', 'y')]
361 l += [KconfigCheck('self_protection', 'kspp', 'SHUFFLE_PAGE_ALLOCATOR', 'y')]
362 l += [KconfigCheck('self_protection', 'kspp', 'FORTIFY_SOURCE', 'y')]
363 l += [KconfigCheck('self_protection', 'kspp', 'DEBUG_LIST', 'y')]
364 l += [KconfigCheck('self_protection', 'kspp', 'DEBUG_SG', 'y')]
365 l += [KconfigCheck('self_protection', 'kspp', 'DEBUG_CREDENTIALS', 'y')]
366 l += [KconfigCheck('self_protection', 'kspp', 'DEBUG_NOTIFIERS', 'y')]
367 l += [KconfigCheck('self_protection', 'kspp', 'INIT_ON_ALLOC_DEFAULT_ON', 'y')]
368 l += [KconfigCheck('self_protection', 'kspp', 'GCC_PLUGIN_LATENT_ENTROPY', 'y')]
369 randstruct_is_set = KconfigCheck('self_protection', 'kspp', 'GCC_PLUGIN_RANDSTRUCT', 'y')
370 l += [randstruct_is_set]
371 hardened_usercopy_is_set = KconfigCheck('self_protection', 'kspp', 'HARDENED_USERCOPY', 'y')
372 l += [hardened_usercopy_is_set]
373 l += [AND(KconfigCheck('self_protection', 'kspp', 'HARDENED_USERCOPY_FALLBACK', 'is not set'),
374 hardened_usercopy_is_set)]
375 l += [AND(KconfigCheck('self_protection', 'kspp', 'HARDENED_USERCOPY_PAGESPAN', 'is not set'),
376 hardened_usercopy_is_set)]
377 l += [OR(KconfigCheck('self_protection', 'kspp', 'MODULE_SIG', 'y'),
379 l += [OR(KconfigCheck('self_protection', 'kspp', 'MODULE_SIG_ALL', 'y'),
381 l += [OR(KconfigCheck('self_protection', 'kspp', 'MODULE_SIG_SHA512', 'y'),
383 l += [OR(KconfigCheck('self_protection', 'kspp', 'MODULE_SIG_FORCE', 'y'),
384 modules_not_set)] # refers to LOCKDOWN
385 l += [OR(KconfigCheck('self_protection', 'kspp', 'INIT_STACK_ALL_ZERO', 'y'),
386 KconfigCheck('self_protection', 'kspp', 'GCC_PLUGIN_STRUCTLEAK_BYREF_ALL', 'y'))]
387 l += [OR(KconfigCheck('self_protection', 'kspp', 'INIT_ON_FREE_DEFAULT_ON', 'y'),
388 KconfigCheck('self_protection', 'kspp', 'PAGE_POISONING_ZERO', 'y'))]
389 # CONFIG_INIT_ON_FREE_DEFAULT_ON was added in v5.3.
390 # CONFIG_PAGE_POISONING_ZERO was removed in v5.11.
391 # Starting from v5.11 CONFIG_PAGE_POISONING unconditionally checks
392 # the 0xAA poison pattern on allocation.
393 # That brings higher performance penalty.
394 if arch in ('X86_64', 'ARM64', 'X86_32'):
395 stackleak_is_set = KconfigCheck('self_protection', 'kspp', 'GCC_PLUGIN_STACKLEAK', 'y')
396 l += [stackleak_is_set]
397 l += [KconfigCheck('self_protection', 'kspp', 'RANDOMIZE_KSTACK_OFFSET_DEFAULT', 'y')]
398 if arch in ('X86_64', 'X86_32'):
399 l += [KconfigCheck('self_protection', 'kspp', 'DEFAULT_MMAP_MIN_ADDR', '65536')]
400 if arch in ('ARM64', 'ARM'):
401 l += [KconfigCheck('self_protection', 'kspp', 'DEFAULT_MMAP_MIN_ADDR', '32768')]
402 l += [KconfigCheck('self_protection', 'kspp', 'SYN_COOKIES', 'y')] # another reason?
404 l += [KconfigCheck('self_protection', 'kspp', 'ARM64_SW_TTBR0_PAN', 'y')]
406 l += [KconfigCheck('self_protection', 'kspp', 'PAGE_TABLE_ISOLATION', 'y')]
407 l += [KconfigCheck('self_protection', 'kspp', 'HIGHMEM64G', 'y')]
408 l += [KconfigCheck('self_protection', 'kspp', 'X86_PAE', 'y')]
410 # 'self_protection', 'maintainer'
411 ubsan_bounds_is_set = KconfigCheck('self_protection', 'maintainer', 'UBSAN_BOUNDS', 'y') # only array index bounds checking
412 l += [ubsan_bounds_is_set] # recommended by Kees Cook in /issues/53
413 l += [AND(KconfigCheck('self_protection', 'maintainer', 'UBSAN_SANITIZE_ALL', 'y'),
414 ubsan_bounds_is_set)] # recommended by Kees Cook in /issues/53
415 l += [AND(KconfigCheck('self_protection', 'maintainer', 'UBSAN_TRAP', 'y'),
416 ubsan_bounds_is_set)] # recommended by Kees Cook in /issues/53
418 # 'self_protection', 'clipos'
419 l += [KconfigCheck('self_protection', 'clipos', 'DEBUG_VIRTUAL', 'y')]
420 l += [KconfigCheck('self_protection', 'clipos', 'STATIC_USERMODEHELPER', 'y')] # needs userspace support
421 l += [KconfigCheck('self_protection', 'clipos', 'EFI_DISABLE_PCI_DMA', 'y')]
422 l += [KconfigCheck('self_protection', 'clipos', 'SLAB_MERGE_DEFAULT', 'is not set')] # slab_nomerge
423 l += [KconfigCheck('self_protection', 'clipos', 'RANDOM_TRUST_BOOTLOADER', 'is not set')]
424 l += [KconfigCheck('self_protection', 'clipos', 'RANDOM_TRUST_CPU', 'is not set')]
425 l += [AND(KconfigCheck('self_protection', 'clipos', 'GCC_PLUGIN_RANDSTRUCT_PERFORMANCE', 'is not set'),
427 if arch in ('X86_64', 'ARM64', 'X86_32'):
428 l += [AND(KconfigCheck('self_protection', 'clipos', 'STACKLEAK_METRICS', 'is not set'),
430 l += [AND(KconfigCheck('self_protection', 'clipos', 'STACKLEAK_RUNTIME_DISABLE', 'is not set'),
432 if arch in ('X86_64', 'X86_32'):
433 l += [AND(KconfigCheck('self_protection', 'clipos', 'INTEL_IOMMU_DEFAULT_ON', 'y'),
434 iommu_support_is_set)]
436 l += [AND(KconfigCheck('self_protection', 'clipos', 'INTEL_IOMMU_SVM', 'y'),
437 iommu_support_is_set)]
439 l += [AND(KconfigCheck('self_protection', 'clipos', 'INTEL_IOMMU', 'y'),
440 iommu_support_is_set)]
442 # 'self_protection', 'my'
443 l += [KconfigCheck('self_protection', 'my', 'RESET_ATTACK_MITIGATION', 'y')] # needs userspace support (systemd)
445 l += [AND(KconfigCheck('self_protection', 'my', 'AMD_IOMMU_V2', 'y'),
446 iommu_support_is_set)]
448 l += [KconfigCheck('self_protection', 'my', 'SHADOW_CALL_STACK', 'y')] # depends on clang, maybe it's alternative to STACKPROTECTOR_STRONG
449 l += [KconfigCheck('self_protection', 'my', 'KASAN_HW_TAGS', 'y')]
450 cfi_clang_is_set = KconfigCheck('self_protection', 'my', 'CFI_CLANG', 'y')
451 l += [cfi_clang_is_set]
452 l += [AND(KconfigCheck('self_protection', 'my', 'CFI_PERMISSIVE', 'is not set'),
456 if arch in ('X86_64', 'ARM64', 'X86_32'):
457 l += [KconfigCheck('security_policy', 'defconfig', 'SECURITY', 'y')] # and choose your favourite LSM
459 l += [KconfigCheck('security_policy', 'kspp', 'SECURITY', 'y')] # and choose your favourite LSM
460 l += [KconfigCheck('security_policy', 'kspp', 'SECURITY_YAMA', 'y')]
461 l += [OR(KconfigCheck('security_policy', 'my', 'SECURITY_WRITABLE_HOOKS', 'is not set'),
462 KconfigCheck('security_policy', 'kspp', 'SECURITY_SELINUX_DISABLE', 'is not set'))]
463 l += [KconfigCheck('security_policy', 'clipos', 'SECURITY_LOCKDOWN_LSM', 'y')]
464 l += [KconfigCheck('security_policy', 'clipos', 'SECURITY_LOCKDOWN_LSM_EARLY', 'y')]
465 l += [KconfigCheck('security_policy', 'clipos', 'LOCK_DOWN_KERNEL_FORCE_CONFIDENTIALITY', 'y')]
466 l += [KconfigCheck('security_policy', 'my', 'SECURITY_SAFESETID', 'y')]
467 loadpin_is_set = KconfigCheck('security_policy', 'my', 'SECURITY_LOADPIN', 'y')
468 l += [loadpin_is_set] # needs userspace support
469 l += [AND(KconfigCheck('security_policy', 'my', 'SECURITY_LOADPIN_ENFORCE', 'y'),
472 # 'cut_attack_surface', 'defconfig'
473 l += [KconfigCheck('cut_attack_surface', 'defconfig', 'SECCOMP', 'y')]
474 l += [KconfigCheck('cut_attack_surface', 'defconfig', 'SECCOMP_FILTER', 'y')]
475 if arch in ('X86_64', 'ARM64', 'X86_32'):
476 l += [OR(KconfigCheck('cut_attack_surface', 'defconfig', 'STRICT_DEVMEM', 'y'),
477 devmem_not_set)] # refers to LOCKDOWN
479 # 'cut_attack_surface', 'kspp'
480 l += [KconfigCheck('cut_attack_surface', 'kspp', 'ACPI_CUSTOM_METHOD', 'is not set')] # refers to LOCKDOWN
481 l += [KconfigCheck('cut_attack_surface', 'kspp', 'COMPAT_BRK', 'is not set')]
482 l += [KconfigCheck('cut_attack_surface', 'kspp', 'DEVKMEM', 'is not set')] # refers to LOCKDOWN
483 l += [KconfigCheck('cut_attack_surface', 'kspp', 'COMPAT_VDSO', 'is not set')]
484 l += [KconfigCheck('cut_attack_surface', 'kspp', 'BINFMT_MISC', 'is not set')]
485 l += [KconfigCheck('cut_attack_surface', 'kspp', 'INET_DIAG', 'is not set')]
486 l += [KconfigCheck('cut_attack_surface', 'kspp', 'KEXEC', 'is not set')] # refers to LOCKDOWN
487 l += [KconfigCheck('cut_attack_surface', 'kspp', 'PROC_KCORE', 'is not set')] # refers to LOCKDOWN
488 l += [KconfigCheck('cut_attack_surface', 'kspp', 'LEGACY_PTYS', 'is not set')]
489 l += [KconfigCheck('cut_attack_surface', 'kspp', 'HIBERNATION', 'is not set')] # refers to LOCKDOWN
490 l += [KconfigCheck('cut_attack_surface', 'kspp', 'IA32_EMULATION', 'is not set')]
491 l += [KconfigCheck('cut_attack_surface', 'kspp', 'X86_X32', 'is not set')]
492 l += [KconfigCheck('cut_attack_surface', 'kspp', 'MODIFY_LDT_SYSCALL', 'is not set')]
493 l += [KconfigCheck('cut_attack_surface', 'kspp', 'OABI_COMPAT', 'is not set')]
494 l += [modules_not_set]
495 l += [devmem_not_set]
496 l += [OR(KconfigCheck('cut_attack_surface', 'kspp', 'IO_STRICT_DEVMEM', 'y'),
497 devmem_not_set)] # refers to LOCKDOWN
499 l += [OR(KconfigCheck('cut_attack_surface', 'kspp', 'STRICT_DEVMEM', 'y'),
500 devmem_not_set)] # refers to LOCKDOWN
502 l += [KconfigCheck('cut_attack_surface', 'kspp', 'LEGACY_VSYSCALL_NONE', 'y')] # 'vsyscall=none'
504 # 'cut_attack_surface', 'grsecurity'
505 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'ZSMALLOC_STAT', 'is not set')]
506 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'PAGE_OWNER', 'is not set')]
507 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'DEBUG_KMEMLEAK', 'is not set')]
508 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'BINFMT_AOUT', 'is not set')]
509 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'KPROBE_EVENTS', 'is not set')]
510 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'UPROBE_EVENTS', 'is not set')]
511 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'GENERIC_TRACER', 'is not set')] # refers to LOCKDOWN
512 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'FUNCTION_TRACER', 'is not set')]
513 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'STACK_TRACER', 'is not set')]
514 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'HIST_TRIGGERS', 'is not set')]
515 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'BLK_DEV_IO_TRACE', 'is not set')]
516 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'PROC_VMCORE', 'is not set')]
517 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'PROC_PAGE_MONITOR', 'is not set')]
518 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'USELIB', 'is not set')]
519 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'CHECKPOINT_RESTORE', 'is not set')]
520 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'USERFAULTFD', 'is not set')]
521 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'HWPOISON_INJECT', 'is not set')]
522 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'MEM_SOFT_DIRTY', 'is not set')]
523 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'DEVPORT', 'is not set')] # refers to LOCKDOWN
524 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'DEBUG_FS', 'is not set')] # refers to LOCKDOWN
525 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'NOTIFIER_ERROR_INJECTION', 'is not set')]
526 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'FAIL_FUTEX', 'is not set')]
527 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'PUNIT_ATOM_DEBUG', 'is not set')]
528 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'ACPI_CONFIGFS', 'is not set')]
529 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'EDAC_DEBUG', 'is not set')]
530 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'DRM_I915_DEBUG', 'is not set')]
531 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'BCACHE_CLOSURES_DEBUG', 'is not set')]
532 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'DVB_C8SECTPFE', 'is not set')]
533 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'MTD_SLRAM', 'is not set')]
534 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'MTD_PHRAM', 'is not set')]
535 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'IO_URING', 'is not set')]
536 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'KCMP', 'is not set')]
537 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'RSEQ', 'is not set')]
538 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'LATENCYTOP', 'is not set')]
539 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'KCOV', 'is not set')]
540 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'PROVIDE_OHCI1394_DMA_INIT', 'is not set')]
541 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'SUNRPC_DEBUG', 'is not set')]
542 l += [AND(KconfigCheck('cut_attack_surface', 'grsecurity', 'PTDUMP_DEBUGFS', 'is not set'),
543 KconfigCheck('cut_attack_surface', 'grsecurity', 'X86_PTDUMP', 'is not set'))]
545 # 'cut_attack_surface', 'maintainer'
546 l += [KconfigCheck('cut_attack_surface', 'maintainer', 'DRM_LEGACY', 'is not set')] # recommended by Daniel Vetter in /issues/38
547 l += [KconfigCheck('cut_attack_surface', 'maintainer', 'FB', 'is not set')] # recommended by Daniel Vetter in /issues/38
548 l += [KconfigCheck('cut_attack_surface', 'maintainer', 'VT', 'is not set')] # recommended by Daniel Vetter in /issues/38
549 l += [KconfigCheck('cut_attack_surface', 'maintainer', 'BLK_DEV_FD', 'is not set')] # recommended by Denis Efremov in /pull/54
551 # 'cut_attack_surface', 'grapheneos'
552 l += [KconfigCheck('cut_attack_surface', 'grapheneos', 'AIO', 'is not set')]
554 # 'cut_attack_surface', 'clipos'
555 l += [KconfigCheck('cut_attack_surface', 'clipos', 'STAGING', 'is not set')]
556 l += [KconfigCheck('cut_attack_surface', 'clipos', 'KSM', 'is not set')] # to prevent FLUSH+RELOAD attack
557 # l += [KconfigCheck('cut_attack_surface', 'clipos', 'IKCONFIG', 'is not set')] # no, IKCONFIG is needed for this check :)
558 l += [KconfigCheck('cut_attack_surface', 'clipos', 'KALLSYMS', 'is not set')]
559 l += [KconfigCheck('cut_attack_surface', 'clipos', 'X86_VSYSCALL_EMULATION', 'is not set')]
560 l += [KconfigCheck('cut_attack_surface', 'clipos', 'MAGIC_SYSRQ', 'is not set')]
561 l += [KconfigCheck('cut_attack_surface', 'clipos', 'KEXEC_FILE', 'is not set')] # refers to LOCKDOWN (permissive)
562 l += [KconfigCheck('cut_attack_surface', 'clipos', 'USER_NS', 'is not set')] # user.max_user_namespaces=0
563 l += [KconfigCheck('cut_attack_surface', 'clipos', 'X86_MSR', 'is not set')] # refers to LOCKDOWN
564 l += [KconfigCheck('cut_attack_surface', 'clipos', 'X86_CPUID', 'is not set')]
565 l += [KconfigCheck('cut_attack_surface', 'clipos', 'X86_IOPL_IOPERM', 'is not set')] # refers to LOCKDOWN
566 l += [KconfigCheck('cut_attack_surface', 'clipos', 'ACPI_TABLE_UPGRADE', 'is not set')] # refers to LOCKDOWN
567 l += [KconfigCheck('cut_attack_surface', 'clipos', 'EFI_CUSTOM_SSDT_OVERLAYS', 'is not set')]
568 l += [AND(KconfigCheck('cut_attack_surface', 'clipos', 'LDISC_AUTOLOAD', 'is not set'),
569 PresenceCheck('LDISC_AUTOLOAD'))]
570 if arch in ('X86_64', 'X86_32'):
571 l += [KconfigCheck('cut_attack_surface', 'clipos', 'X86_INTEL_TSX_MODE_OFF', 'y')] # tsx=off
573 # 'cut_attack_surface', 'lockdown'
574 l += [KconfigCheck('cut_attack_surface', 'lockdown', 'EFI_TEST', 'is not set')] # refers to LOCKDOWN
575 l += [KconfigCheck('cut_attack_surface', 'lockdown', 'BPF_SYSCALL', 'is not set')] # refers to LOCKDOWN
576 l += [KconfigCheck('cut_attack_surface', 'lockdown', 'MMIOTRACE_TEST', 'is not set')] # refers to LOCKDOWN
577 l += [KconfigCheck('cut_attack_surface', 'lockdown', 'KPROBES', 'is not set')] # refers to LOCKDOWN
579 # 'cut_attack_surface', 'my'
580 l += [OR(KconfigCheck('cut_attack_surface', 'my', 'TRIM_UNUSED_KSYMS', 'y'),
582 l += [KconfigCheck('cut_attack_surface', 'my', 'MMIOTRACE', 'is not set')] # refers to LOCKDOWN (permissive)
583 l += [KconfigCheck('cut_attack_surface', 'my', 'LIVEPATCH', 'is not set')]
584 l += [KconfigCheck('cut_attack_surface', 'my', 'IP_DCCP', 'is not set')]
585 l += [KconfigCheck('cut_attack_surface', 'my', 'IP_SCTP', 'is not set')]
586 l += [KconfigCheck('cut_attack_surface', 'my', 'FTRACE', 'is not set')] # refers to LOCKDOWN
587 l += [KconfigCheck('cut_attack_surface', 'my', 'VIDEO_VIVID', 'is not set')]
588 l += [KconfigCheck('cut_attack_surface', 'my', 'INPUT_EVBUG', 'is not set')] # Can be used as a keylogger
591 if arch in ('X86_64', 'ARM64', 'X86_32'):
592 l += [KconfigCheck('harden_userspace', 'defconfig', 'INTEGRITY', 'y')]
594 l += [KconfigCheck('harden_userspace', 'my', 'INTEGRITY', 'y')]
596 l += [KconfigCheck('harden_userspace', 'defconfig', 'ARM64_MTE', 'y')]
597 if arch in ('ARM', 'X86_32'):
598 l += [KconfigCheck('harden_userspace', 'defconfig', 'VMSPLIT_3G', 'y')]
599 if arch in ('X86_64', 'ARM64'):
600 l += [KconfigCheck('harden_userspace', 'clipos', 'ARCH_MMAP_RND_BITS', '32')]
601 if arch in ('X86_32', 'ARM'):
602 l += [KconfigCheck('harden_userspace', 'my', 'ARCH_MMAP_RND_BITS', '16')]
604 # l += [KconfigCheck('feature_test', 'my', 'LKDTM', 'm')] # only for debugging!
607 def print_unknown_options(checklist, parsed_options):
609 for opt in checklist:
610 if hasattr(opt, 'opts'):
612 if hasattr(o, 'name'):
613 known_options.append(o.name)
615 known_options.append(opt.name)
616 for option, value in parsed_options.items():
617 if option not in known_options:
618 print('[?] No rule for option {} ({})'.format(option, value))
621 def print_checklist(mode, checklist, with_results):
625 opt = ['CONFIG_'+o.name, o.expected, o.decision, o.reason]
629 print(json.dumps(opts))
636 print('=' * sep_line_len)
637 print('{:^40}|{:^7}|{:^11}|{:^10}|{:^18}'.format('option name', 'type', 'desired val', 'decision', 'reason'), end='')
639 print('| {}'.format('check result'), end='')
641 print('=' * sep_line_len)
644 for opt in checklist:
646 if mode == 'show_ok':
647 if not opt.result.startswith('OK'):
649 if mode == 'show_fail':
650 if not opt.result.startswith('FAIL'):
652 opt.table_print(mode, with_results)
654 if mode == 'verbose':
655 print('-' * sep_line_len)
660 fail_count = len(list(filter(lambda opt: opt.result.startswith('FAIL'), checklist)))
662 ok_count = len(list(filter(lambda opt: opt.result.startswith('OK'), checklist)))
664 if mode == 'show_ok':
665 fail_suppressed = ' (suppressed in output)'
666 if mode == 'show_fail':
667 ok_suppressed = ' (suppressed in output)'
669 print('[+] Config check is finished: \'OK\' - {}{} / \'FAIL\' - {}{}'.format(ok_count, ok_suppressed, fail_count, fail_suppressed))
672 def perform_check(opt, parsed_options, kernel_version):
673 if hasattr(opt, 'opts'):
674 # prepare ComplexOptCheck
676 if hasattr(o, 'opts'):
677 # Recursion for nested ComplexOptChecks
678 perform_check(o, parsed_options, kernel_version)
679 if hasattr(o, 'state'):
680 o.state = parsed_options.get(o.name, None)
681 if hasattr(o, 'ver'):
682 o.ver = kernel_version
684 # prepare simple check, opt.state is mandatory
685 if not hasattr(opt, 'state'):
686 sys.exit('[!] ERROR: bad simple check {}'.format(vars(opt)))
687 opt.state = parsed_options.get(opt.name, None)
691 def perform_checks(checklist, parsed_options, kernel_version):
692 for opt in checklist:
693 perform_check(opt, parsed_options, kernel_version)
696 def parse_config_file(parsed_options, fname):
697 with open(fname, 'r') as f:
698 opt_is_on = re.compile("CONFIG_[a-zA-Z0-9_]*=[a-zA-Z0-9_\"]*")
699 opt_is_off = re.compile("# CONFIG_[a-zA-Z0-9_]* is not set")
701 for line in f.readlines():
706 if opt_is_on.match(line):
707 option, value = line[7:].split('=', 1)
708 elif opt_is_off.match(line):
709 option, value = line[9:].split(' ', 1)
710 if value != 'is not set':
711 sys.exit('[!] ERROR: bad disabled config option "{}"'.format(line))
713 if option in parsed_options:
714 sys.exit('[!] ERROR: config option "{}" exists multiple times'.format(line))
717 parsed_options[option] = value
719 return parsed_options
725 # - reporting about unknown kernel options in the config
726 # - verbose printing of ComplexOptCheck items
727 # * json mode for printing the results in JSON format
728 report_modes = ['verbose', 'json', 'show_ok', 'show_fail']
729 supported_archs = ['X86_64', 'X86_32', 'ARM64', 'ARM']
730 parser = ArgumentParser(prog='kconfig-hardened-check',
731 description='A tool for checking the security hardening options of the Linux kernel')
732 parser.add_argument('--version', action='version', version='%(prog)s ' + __version__)
733 parser.add_argument('-p', '--print', choices=supported_archs,
734 help='print security hardening preferences for the selected architecture')
735 parser.add_argument('-c', '--config',
736 help='check the kernel config file against these preferences')
737 parser.add_argument('-m', '--mode', choices=report_modes,
738 help='choose the report mode')
739 args = parser.parse_args()
745 print("[+] Special report mode: {}".format(mode))
747 config_checklist = []
751 print('[+] Config file to check: {}'.format(args.config))
753 arch, msg = detect_arch(args.config, supported_archs)
755 sys.exit('[!] ERROR: {}'.format(msg))
757 print('[+] Detected architecture: {}'.format(arch))
759 kernel_version, msg = detect_version(args.config)
760 if not kernel_version:
761 sys.exit('[!] ERROR: {}'.format(msg))
763 print('[+] Detected kernel version: {}.{}'.format(kernel_version[0], kernel_version[1]))
765 construct_checklist(config_checklist, arch)
766 parsed_options = OrderedDict()
767 parse_config_file(parsed_options, args.config)
768 perform_checks(config_checklist, parsed_options, kernel_version)
770 if mode == 'verbose':
771 print_unknown_options(config_checklist, parsed_options)
772 print_checklist(mode, config_checklist, True)
777 if mode in ('show_ok', 'show_fail'):
778 sys.exit('[!] ERROR: please use "{}" mode for checking the kernel config'.format(mode))
780 construct_checklist(config_checklist, arch)
782 print('[+] Printing kernel security hardening preferences for {}...'.format(arch))
783 print_checklist(mode, config_checklist, False)
789 if __name__ == '__main__':