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):
111 def table_print(self, _mode, with_results):
112 print('CONFIG_{:<33}|{:^11}|{:^10}|{:^18}'.format(self.name, self.expected, self.decision, self.reason), end='')
114 print('| {}'.format(self.result), end='')
118 def __init__(self, ver_expected):
119 self.ver_expected = ver_expected
124 if self.ver[0] > self.ver_expected[0]:
125 self.result = 'OK: version >= ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
127 if self.ver[0] < self.ver_expected[0]:
128 self.result = 'FAIL: version < ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
130 if self.ver[1] >= self.ver_expected[1]:
131 self.result = 'OK: version >= ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
133 self.result = 'FAIL: version < ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
136 def table_print(self, _mode, with_results):
137 ver_req = 'kernel version >= ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
138 print('{:<82}'.format(ver_req), end='')
140 print('| {}'.format(self.result), end='')
144 def __init__(self, name):
150 if self.state is None:
151 self.result = 'FAIL: not present'
153 self.result = 'OK: is present'
156 def table_print(self, _mode, with_results):
157 print('CONFIG_{:<75}'.format(self.name + ' is present'), end='')
159 print('| {}'.format(self.result), end='')
162 class ComplexOptCheck:
163 def __init__(self, *opts):
166 sys.exit('[!] ERROR: empty {} check'.format(self.__class__.__name__))
167 if not isinstance(opts[0], KconfigCheck):
168 sys.exit('[!] ERROR: invalid {} check: {}'.format(self.__class__.__name__, opts))
173 return self.opts[0].name
177 return self.opts[0].expected
181 return self.opts[0].decision
185 return self.opts[0].reason
187 def table_print(self, mode, with_results):
188 if mode == 'verbose':
189 print(' {:78}'.format('<<< ' + self.__class__.__name__ + ' >>>'), end='')
191 print('| {}'.format(self.result), end='')
194 o.table_print(mode, with_results)
197 o.table_print(mode, False)
199 print('| {}'.format(self.result), end='')
202 class OR(ComplexOptCheck):
203 # self.opts[0] is the option that this OR-check is about.
205 # OR(<X_is_hardened>, <X_is_disabled>)
206 # OR(<X_is_hardened>, <old_X_is_hardened>)
210 sys.exit('[!] ERROR: invalid OR check')
212 for i, opt in enumerate(self.opts):
215 if opt.result != 'OK' or i == 0:
216 # Preserve additional explanation of this OK result.
217 # Simple OK is enough only for the main option that
218 # this OR-check is about.
219 self.result = opt.result
221 # Simple OK is not enough for additional checks.
222 self.result = 'OK: CONFIG_{} "{}"'.format(opt.name, opt.expected)
224 self.result = self.opts[0].result
228 class AND(ComplexOptCheck):
229 # self.opts[0] is the option that this AND-check is about.
231 # AND(<suboption>, <main_option>)
232 # Suboption is not checked if checking of the main_option is failed.
233 # AND(<X_is_disabled>, <old_X_is_disabled>)
236 for i, opt in reversed(list(enumerate(self.opts))):
239 self.result = opt.result
242 # This FAIL is caused by additional checks,
243 # and not by the main option that this AND-check is about.
244 # Describe the reason of the FAIL.
245 if opt.result.startswith('FAIL: \"') or opt.result == 'FAIL: not found':
246 self.result = 'FAIL: CONFIG_{} not "{}"'.format(opt.name, opt.expected)
247 elif opt.result == 'FAIL: not present':
248 self.result = 'FAIL: CONFIG_{} not present'.format(opt.name)
250 # This FAIL message is self-explaining.
251 self.result = opt.result
254 sys.exit('[!] ERROR: invalid AND check')
257 def detect_arch(fname, archs):
258 with open(fname, 'r') as f:
259 arch_pattern = re.compile("CONFIG_[a-zA-Z0-9_]*=y")
261 for line in f.readlines():
262 if arch_pattern.match(line):
263 option, _ = line[7:].split('=', 1)
268 return None, 'more than one supported architecture is detected'
270 return None, 'failed to detect architecture'
274 def detect_version(fname):
275 with open(fname, 'r') as f:
276 ver_pattern = re.compile("# Linux/.* Kernel Configuration")
277 for line in f.readlines():
278 if ver_pattern.match(line):
282 ver_numbers = ver_str.split('.')
283 if len(ver_numbers) < 3 or not ver_numbers[0].isdigit() or not ver_numbers[1].isdigit():
284 msg = 'failed to parse the version "' + ver_str + '"'
286 return (int(ver_numbers[0]), int(ver_numbers[1])), None
287 return None, 'no kernel version detected'
290 def construct_checklist(l, arch):
291 # Calling the KconfigCheck class constructor:
292 # KconfigCheck(reason, decision, name, expected)
294 modules_not_set = KconfigCheck('cut_attack_surface', 'kspp', 'MODULES', 'is not set')
295 devmem_not_set = KconfigCheck('cut_attack_surface', 'kspp', 'DEVMEM', 'is not set') # refers to LOCKDOWN
297 # 'self_protection', 'defconfig'
298 l += [KconfigCheck('self_protection', 'defconfig', 'BUG', 'y')]
299 l += [KconfigCheck('self_protection', 'defconfig', 'SLUB_DEBUG', 'y')]
300 l += [KconfigCheck('self_protection', 'defconfig', 'GCC_PLUGINS', 'y')]
301 l += [OR(KconfigCheck('self_protection', 'defconfig', 'STACKPROTECTOR_STRONG', 'y'),
302 KconfigCheck('self_protection', 'defconfig', 'CC_STACKPROTECTOR_STRONG', 'y'))]
303 l += [OR(KconfigCheck('self_protection', 'defconfig', 'STRICT_KERNEL_RWX', 'y'),
304 KconfigCheck('self_protection', 'defconfig', 'DEBUG_RODATA', 'y'))] # before v4.11
305 l += [OR(KconfigCheck('self_protection', 'defconfig', 'STRICT_MODULE_RWX', 'y'),
306 KconfigCheck('self_protection', 'defconfig', 'DEBUG_SET_MODULE_RONX', 'y'),
307 modules_not_set)] # DEBUG_SET_MODULE_RONX was before v4.11
308 l += [OR(KconfigCheck('self_protection', 'defconfig', 'REFCOUNT_FULL', 'y'),
309 VerCheck((5, 5)))] # REFCOUNT_FULL is enabled by default since v5.5
310 iommu_support_is_set = KconfigCheck('self_protection', 'defconfig', 'IOMMU_SUPPORT', 'y')
311 l += [iommu_support_is_set] # is needed for mitigating DMA attacks
312 if arch in ('X86_64', 'ARM64', 'X86_32'):
313 l += [KconfigCheck('self_protection', 'defconfig', 'RANDOMIZE_BASE', 'y')]
314 l += [KconfigCheck('self_protection', 'defconfig', 'THREAD_INFO_IN_TASK', 'y')]
315 if arch in ('X86_64', 'ARM64'):
316 l += [KconfigCheck('self_protection', 'defconfig', 'VMAP_STACK', 'y')]
317 if arch in ('X86_64', 'X86_32'):
318 l += [KconfigCheck('self_protection', 'defconfig', 'MICROCODE', 'y')] # is needed for mitigating CPU bugs
319 l += [KconfigCheck('self_protection', 'defconfig', 'RETPOLINE', 'y')]
320 l += [KconfigCheck('self_protection', 'defconfig', 'X86_SMAP', 'y')]
321 l += [KconfigCheck('self_protection', 'defconfig', 'SYN_COOKIES', 'y')] # another reason?
322 l += [OR(KconfigCheck('self_protection', 'defconfig', 'X86_UMIP', 'y'),
323 KconfigCheck('self_protection', 'defconfig', 'X86_INTEL_UMIP', 'y'))]
324 if arch in ('ARM64', 'ARM'):
325 l += [KconfigCheck('self_protection', 'defconfig', 'STACKPROTECTOR_PER_TASK', 'y')]
327 l += [KconfigCheck('self_protection', 'defconfig', 'PAGE_TABLE_ISOLATION', 'y')]
328 l += [KconfigCheck('self_protection', 'defconfig', 'RANDOMIZE_MEMORY', 'y')]
329 l += [AND(KconfigCheck('self_protection', 'defconfig', 'INTEL_IOMMU', 'y'),
330 iommu_support_is_set)]
331 l += [AND(KconfigCheck('self_protection', 'defconfig', 'AMD_IOMMU', 'y'),
332 iommu_support_is_set)]
334 l += [KconfigCheck('self_protection', 'defconfig', 'ARM64_PAN', 'y')]
335 l += [KconfigCheck('self_protection', 'defconfig', 'ARM64_EPAN', 'y')]
336 l += [KconfigCheck('self_protection', 'defconfig', 'UNMAP_KERNEL_AT_EL0', 'y')]
337 l += [OR(KconfigCheck('self_protection', 'defconfig', 'HARDEN_EL2_VECTORS', 'y'),
338 AND(KconfigCheck('self_protection', 'defconfig', 'RANDOMIZE_BASE', 'y'),
339 VerCheck((5, 9))))] # HARDEN_EL2_VECTORS was included in RANDOMIZE_BASE in v5.9
340 l += [KconfigCheck('self_protection', 'defconfig', 'RODATA_FULL_DEFAULT_ENABLED', 'y')]
341 l += [KconfigCheck('self_protection', 'defconfig', 'ARM64_PTR_AUTH_KERNEL', 'y')]
342 l += [KconfigCheck('self_protection', 'defconfig', 'ARM64_BTI_KERNEL', 'y')]
343 l += [OR(KconfigCheck('self_protection', 'defconfig', 'HARDEN_BRANCH_PREDICTOR', 'y'),
344 VerCheck((5, 10)))] # HARDEN_BRANCH_PREDICTOR is enabled by default since v5.10
345 l += [KconfigCheck('self_protection', 'defconfig', 'ARM64_MTE', 'y')]
347 l += [KconfigCheck('self_protection', 'defconfig', 'CPU_SW_DOMAIN_PAN', 'y')]
348 l += [KconfigCheck('self_protection', 'defconfig', 'HARDEN_BRANCH_PREDICTOR', 'y')]
350 # 'self_protection', 'kspp'
351 l += [KconfigCheck('self_protection', 'kspp', 'SECURITY_DMESG_RESTRICT', 'y')]
352 l += [KconfigCheck('self_protection', 'kspp', 'BUG_ON_DATA_CORRUPTION', 'y')]
353 l += [KconfigCheck('self_protection', 'kspp', 'DEBUG_WX', 'y')]
354 l += [KconfigCheck('self_protection', 'kspp', 'SCHED_STACK_END_CHECK', 'y')]
355 l += [KconfigCheck('self_protection', 'kspp', 'SLAB_FREELIST_HARDENED', 'y')]
356 l += [KconfigCheck('self_protection', 'kspp', 'SLAB_FREELIST_RANDOM', 'y')]
357 l += [KconfigCheck('self_protection', 'kspp', 'SHUFFLE_PAGE_ALLOCATOR', 'y')]
358 l += [KconfigCheck('self_protection', 'kspp', 'FORTIFY_SOURCE', 'y')]
359 l += [KconfigCheck('self_protection', 'kspp', 'DEBUG_LIST', 'y')]
360 l += [KconfigCheck('self_protection', 'kspp', 'DEBUG_SG', 'y')]
361 l += [KconfigCheck('self_protection', 'kspp', 'DEBUG_CREDENTIALS', 'y')]
362 l += [KconfigCheck('self_protection', 'kspp', 'DEBUG_NOTIFIERS', 'y')]
363 l += [KconfigCheck('self_protection', 'kspp', 'INIT_ON_ALLOC_DEFAULT_ON', 'y')]
364 l += [KconfigCheck('self_protection', 'kspp', 'GCC_PLUGIN_LATENT_ENTROPY', 'y')]
365 randstruct_is_set = KconfigCheck('self_protection', 'kspp', 'GCC_PLUGIN_RANDSTRUCT', 'y')
366 l += [randstruct_is_set]
367 hardened_usercopy_is_set = KconfigCheck('self_protection', 'kspp', 'HARDENED_USERCOPY', 'y')
368 l += [hardened_usercopy_is_set]
369 l += [AND(KconfigCheck('self_protection', 'kspp', 'HARDENED_USERCOPY_FALLBACK', 'is not set'),
370 hardened_usercopy_is_set)]
371 l += [AND(KconfigCheck('self_protection', 'kspp', 'HARDENED_USERCOPY_PAGESPAN', 'is not set'),
372 hardened_usercopy_is_set)]
373 l += [OR(KconfigCheck('self_protection', 'kspp', 'MODULE_SIG', 'y'),
375 l += [OR(KconfigCheck('self_protection', 'kspp', 'MODULE_SIG_ALL', 'y'),
377 l += [OR(KconfigCheck('self_protection', 'kspp', 'MODULE_SIG_SHA512', 'y'),
379 l += [OR(KconfigCheck('self_protection', 'kspp', 'MODULE_SIG_FORCE', 'y'),
380 modules_not_set)] # refers to LOCKDOWN
381 l += [OR(KconfigCheck('self_protection', 'kspp', 'INIT_STACK_ALL_ZERO', 'y'),
382 KconfigCheck('self_protection', 'kspp', 'GCC_PLUGIN_STRUCTLEAK_BYREF_ALL', 'y'))]
383 l += [OR(KconfigCheck('self_protection', 'kspp', 'INIT_ON_FREE_DEFAULT_ON', 'y'),
384 KconfigCheck('self_protection', 'kspp', 'PAGE_POISONING_ZERO', 'y'))]
385 # CONFIG_INIT_ON_FREE_DEFAULT_ON was added in v5.3.
386 # CONFIG_PAGE_POISONING_ZERO was removed in v5.11.
387 # Starting from v5.11 CONFIG_PAGE_POISONING unconditionally checks
388 # the 0xAA poison pattern on allocation.
389 # That brings higher performance penalty.
390 if arch in ('X86_64', 'ARM64', 'X86_32'):
391 stackleak_is_set = KconfigCheck('self_protection', 'kspp', 'GCC_PLUGIN_STACKLEAK', 'y')
392 l += [stackleak_is_set]
393 l += [KconfigCheck('self_protection', 'kspp', 'RANDOMIZE_KSTACK_OFFSET_DEFAULT', 'y')]
394 if arch in ('X86_64', 'X86_32'):
395 l += [KconfigCheck('self_protection', 'kspp', 'DEFAULT_MMAP_MIN_ADDR', '65536')]
396 if arch in ('ARM64', 'ARM'):
397 l += [KconfigCheck('self_protection', 'kspp', 'DEFAULT_MMAP_MIN_ADDR', '32768')]
398 l += [KconfigCheck('self_protection', 'kspp', 'SYN_COOKIES', 'y')] # another reason?
400 l += [KconfigCheck('self_protection', 'kspp', 'ARM64_SW_TTBR0_PAN', 'y')]
402 l += [KconfigCheck('self_protection', 'kspp', 'PAGE_TABLE_ISOLATION', 'y')]
403 l += [KconfigCheck('self_protection', 'kspp', 'HIGHMEM64G', 'y')]
404 l += [KconfigCheck('self_protection', 'kspp', 'X86_PAE', 'y')]
406 # 'self_protection', 'maintainer'
407 ubsan_bounds_is_set = KconfigCheck('self_protection', 'maintainer', 'UBSAN_BOUNDS', 'y') # only array index bounds checking
408 l += [ubsan_bounds_is_set] # recommended by Kees Cook in /issues/53
409 l += [AND(KconfigCheck('self_protection', 'maintainer', 'UBSAN_SANITIZE_ALL', 'y'),
410 ubsan_bounds_is_set)] # recommended by Kees Cook in /issues/53
411 l += [AND(KconfigCheck('self_protection', 'maintainer', 'UBSAN_TRAP', 'y'),
412 ubsan_bounds_is_set)] # recommended by Kees Cook in /issues/53
414 # 'self_protection', 'clipos'
415 l += [KconfigCheck('self_protection', 'clipos', 'DEBUG_VIRTUAL', 'y')]
416 l += [KconfigCheck('self_protection', 'clipos', 'STATIC_USERMODEHELPER', 'y')] # needs userspace support
417 l += [KconfigCheck('self_protection', 'clipos', 'EFI_DISABLE_PCI_DMA', 'y')]
418 l += [KconfigCheck('self_protection', 'clipos', 'SLAB_MERGE_DEFAULT', 'is not set')] # slab_nomerge
419 l += [KconfigCheck('self_protection', 'clipos', 'RANDOM_TRUST_BOOTLOADER', 'is not set')]
420 l += [KconfigCheck('self_protection', 'clipos', 'RANDOM_TRUST_CPU', 'is not set')]
421 l += [AND(KconfigCheck('self_protection', 'clipos', 'GCC_PLUGIN_RANDSTRUCT_PERFORMANCE', 'is not set'),
423 if arch in ('X86_64', 'ARM64', 'X86_32'):
424 l += [AND(KconfigCheck('self_protection', 'clipos', 'STACKLEAK_METRICS', 'is not set'),
426 l += [AND(KconfigCheck('self_protection', 'clipos', 'STACKLEAK_RUNTIME_DISABLE', 'is not set'),
428 if arch in ('X86_64', 'X86_32'):
429 l += [AND(KconfigCheck('self_protection', 'clipos', 'INTEL_IOMMU_DEFAULT_ON', 'y'),
430 iommu_support_is_set)]
432 l += [AND(KconfigCheck('self_protection', 'clipos', 'INTEL_IOMMU_SVM', 'y'),
433 iommu_support_is_set)]
435 l += [AND(KconfigCheck('self_protection', 'clipos', 'INTEL_IOMMU', 'y'),
436 iommu_support_is_set)]
438 # 'self_protection', 'my'
439 l += [KconfigCheck('self_protection', 'my', 'RESET_ATTACK_MITIGATION', 'y')] # needs userspace support (systemd)
441 l += [AND(KconfigCheck('self_protection', 'my', 'AMD_IOMMU_V2', 'y'),
442 iommu_support_is_set)]
444 l += [KconfigCheck('self_protection', 'my', 'SHADOW_CALL_STACK', 'y')] # depends on clang, maybe it's alternative to STACKPROTECTOR_STRONG
445 l += [KconfigCheck('self_protection', 'my', 'KASAN_HW_TAGS', 'y')]
446 cfi_clang_is_set = KconfigCheck('self_protection', 'my', 'CFI_CLANG', 'y')
447 l += [cfi_clang_is_set]
448 l += [AND(KconfigCheck('self_protection', 'my', 'CFI_PERMISSIVE', 'is not set'),
452 if arch in ('X86_64', 'ARM64', 'X86_32'):
453 l += [KconfigCheck('security_policy', 'defconfig', 'SECURITY', 'y')] # and choose your favourite LSM
455 l += [KconfigCheck('security_policy', 'kspp', 'SECURITY', 'y')] # and choose your favourite LSM
456 l += [KconfigCheck('security_policy', 'kspp', 'SECURITY_YAMA', 'y')]
457 l += [OR(KconfigCheck('security_policy', 'my', 'SECURITY_WRITABLE_HOOKS', 'is not set'),
458 KconfigCheck('security_policy', 'kspp', 'SECURITY_SELINUX_DISABLE', 'is not set'))]
459 l += [KconfigCheck('security_policy', 'clipos', 'SECURITY_LOCKDOWN_LSM', 'y')]
460 l += [KconfigCheck('security_policy', 'clipos', 'SECURITY_LOCKDOWN_LSM_EARLY', 'y')]
461 l += [KconfigCheck('security_policy', 'clipos', 'LOCK_DOWN_KERNEL_FORCE_CONFIDENTIALITY', 'y')]
462 l += [KconfigCheck('security_policy', 'my', 'SECURITY_SAFESETID', 'y')]
463 loadpin_is_set = KconfigCheck('security_policy', 'my', 'SECURITY_LOADPIN', 'y')
464 l += [loadpin_is_set] # needs userspace support
465 l += [AND(KconfigCheck('security_policy', 'my', 'SECURITY_LOADPIN_ENFORCE', 'y'),
468 # 'cut_attack_surface', 'defconfig'
469 l += [KconfigCheck('cut_attack_surface', 'defconfig', 'SECCOMP', 'y')]
470 l += [KconfigCheck('cut_attack_surface', 'defconfig', 'SECCOMP_FILTER', 'y')]
471 if arch in ('X86_64', 'ARM64', 'X86_32'):
472 l += [OR(KconfigCheck('cut_attack_surface', 'defconfig', 'STRICT_DEVMEM', 'y'),
473 devmem_not_set)] # refers to LOCKDOWN
475 # 'cut_attack_surface', 'kspp'
476 l += [KconfigCheck('cut_attack_surface', 'kspp', 'ACPI_CUSTOM_METHOD', 'is not set')] # refers to LOCKDOWN
477 l += [KconfigCheck('cut_attack_surface', 'kspp', 'COMPAT_BRK', 'is not set')]
478 l += [KconfigCheck('cut_attack_surface', 'kspp', 'DEVKMEM', 'is not set')] # refers to LOCKDOWN
479 l += [KconfigCheck('cut_attack_surface', 'kspp', 'COMPAT_VDSO', 'is not set')]
480 l += [KconfigCheck('cut_attack_surface', 'kspp', 'BINFMT_MISC', 'is not set')]
481 l += [KconfigCheck('cut_attack_surface', 'kspp', 'INET_DIAG', 'is not set')]
482 l += [KconfigCheck('cut_attack_surface', 'kspp', 'KEXEC', 'is not set')] # refers to LOCKDOWN
483 l += [KconfigCheck('cut_attack_surface', 'kspp', 'PROC_KCORE', 'is not set')] # refers to LOCKDOWN
484 l += [KconfigCheck('cut_attack_surface', 'kspp', 'LEGACY_PTYS', 'is not set')]
485 l += [KconfigCheck('cut_attack_surface', 'kspp', 'HIBERNATION', 'is not set')] # refers to LOCKDOWN
486 l += [KconfigCheck('cut_attack_surface', 'kspp', 'IA32_EMULATION', 'is not set')]
487 l += [KconfigCheck('cut_attack_surface', 'kspp', 'X86_X32', 'is not set')]
488 l += [KconfigCheck('cut_attack_surface', 'kspp', 'MODIFY_LDT_SYSCALL', 'is not set')]
489 l += [KconfigCheck('cut_attack_surface', 'kspp', 'OABI_COMPAT', 'is not set')]
490 l += [modules_not_set]
491 l += [devmem_not_set]
492 l += [OR(KconfigCheck('cut_attack_surface', 'kspp', 'IO_STRICT_DEVMEM', 'y'),
493 devmem_not_set)] # refers to LOCKDOWN
495 l += [OR(KconfigCheck('cut_attack_surface', 'kspp', 'STRICT_DEVMEM', 'y'),
496 devmem_not_set)] # refers to LOCKDOWN
498 l += [KconfigCheck('cut_attack_surface', 'kspp', 'LEGACY_VSYSCALL_NONE', 'y')] # 'vsyscall=none'
500 # 'cut_attack_surface', 'grsecurity'
501 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'ZSMALLOC_STAT', 'is not set')]
502 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'PAGE_OWNER', 'is not set')]
503 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'DEBUG_KMEMLEAK', 'is not set')]
504 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'BINFMT_AOUT', 'is not set')]
505 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'KPROBE_EVENTS', 'is not set')]
506 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'UPROBE_EVENTS', 'is not set')]
507 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'GENERIC_TRACER', 'is not set')] # refers to LOCKDOWN
508 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'FUNCTION_TRACER', 'is not set')]
509 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'STACK_TRACER', 'is not set')]
510 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'HIST_TRIGGERS', 'is not set')]
511 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'BLK_DEV_IO_TRACE', 'is not set')]
512 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'PROC_VMCORE', 'is not set')]
513 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'PROC_PAGE_MONITOR', 'is not set')]
514 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'USELIB', 'is not set')]
515 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'CHECKPOINT_RESTORE', 'is not set')]
516 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'USERFAULTFD', 'is not set')]
517 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'HWPOISON_INJECT', 'is not set')]
518 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'MEM_SOFT_DIRTY', 'is not set')]
519 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'DEVPORT', 'is not set')] # refers to LOCKDOWN
520 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'DEBUG_FS', 'is not set')] # refers to LOCKDOWN
521 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'NOTIFIER_ERROR_INJECTION', 'is not set')]
522 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'FAIL_FUTEX', 'is not set')]
523 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'PUNIT_ATOM_DEBUG', 'is not set')]
524 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'ACPI_CONFIGFS', 'is not set')]
525 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'EDAC_DEBUG', 'is not set')]
526 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'DRM_I915_DEBUG', 'is not set')]
527 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'BCACHE_CLOSURES_DEBUG', 'is not set')]
528 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'DVB_C8SECTPFE', 'is not set')]
529 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'MTD_SLRAM', 'is not set')]
530 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'MTD_PHRAM', 'is not set')]
531 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'IO_URING', 'is not set')]
532 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'KCMP', 'is not set')]
533 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'RSEQ', 'is not set')]
534 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'LATENCYTOP', 'is not set')]
535 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'KCOV', 'is not set')]
536 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'PROVIDE_OHCI1394_DMA_INIT', 'is not set')]
537 l += [KconfigCheck('cut_attack_surface', 'grsecurity', 'SUNRPC_DEBUG', 'is not set')]
538 l += [AND(KconfigCheck('cut_attack_surface', 'grsecurity', 'PTDUMP_DEBUGFS', 'is not set'),
539 KconfigCheck('cut_attack_surface', 'grsecurity', 'X86_PTDUMP', 'is not set'))]
541 # 'cut_attack_surface', 'maintainer'
542 l += [KconfigCheck('cut_attack_surface', 'maintainer', 'DRM_LEGACY', 'is not set')] # recommended by Daniel Vetter in /issues/38
543 l += [KconfigCheck('cut_attack_surface', 'maintainer', 'FB', 'is not set')] # recommended by Daniel Vetter in /issues/38
544 l += [KconfigCheck('cut_attack_surface', 'maintainer', 'VT', 'is not set')] # recommended by Daniel Vetter in /issues/38
545 l += [KconfigCheck('cut_attack_surface', 'maintainer', 'BLK_DEV_FD', 'is not set')] # recommended by Denis Efremov in /pull/54
547 # 'cut_attack_surface', 'grapheneos'
548 l += [KconfigCheck('cut_attack_surface', 'grapheneos', 'AIO', 'is not set')]
550 # 'cut_attack_surface', 'clipos'
551 l += [KconfigCheck('cut_attack_surface', 'clipos', 'STAGING', 'is not set')]
552 l += [KconfigCheck('cut_attack_surface', 'clipos', 'KSM', 'is not set')] # to prevent FLUSH+RELOAD attack
553 # l += [KconfigCheck('cut_attack_surface', 'clipos', 'IKCONFIG', 'is not set')] # no, IKCONFIG is needed for this check :)
554 l += [KconfigCheck('cut_attack_surface', 'clipos', 'KALLSYMS', 'is not set')]
555 l += [KconfigCheck('cut_attack_surface', 'clipos', 'X86_VSYSCALL_EMULATION', 'is not set')]
556 l += [KconfigCheck('cut_attack_surface', 'clipos', 'MAGIC_SYSRQ', 'is not set')]
557 l += [KconfigCheck('cut_attack_surface', 'clipos', 'KEXEC_FILE', 'is not set')] # refers to LOCKDOWN (permissive)
558 l += [KconfigCheck('cut_attack_surface', 'clipos', 'USER_NS', 'is not set')] # user.max_user_namespaces=0
559 l += [KconfigCheck('cut_attack_surface', 'clipos', 'X86_MSR', 'is not set')] # refers to LOCKDOWN
560 l += [KconfigCheck('cut_attack_surface', 'clipos', 'X86_CPUID', 'is not set')]
561 l += [KconfigCheck('cut_attack_surface', 'clipos', 'X86_IOPL_IOPERM', 'is not set')] # refers to LOCKDOWN
562 l += [KconfigCheck('cut_attack_surface', 'clipos', 'ACPI_TABLE_UPGRADE', 'is not set')] # refers to LOCKDOWN
563 l += [KconfigCheck('cut_attack_surface', 'clipos', 'EFI_CUSTOM_SSDT_OVERLAYS', 'is not set')]
564 l += [AND(KconfigCheck('cut_attack_surface', 'clipos', 'LDISC_AUTOLOAD', 'is not set'),
565 PresenceCheck('LDISC_AUTOLOAD'))]
566 if arch in ('X86_64', 'X86_32'):
567 l += [KconfigCheck('cut_attack_surface', 'clipos', 'X86_INTEL_TSX_MODE_OFF', 'y')] # tsx=off
569 # 'cut_attack_surface', 'lockdown'
570 l += [KconfigCheck('cut_attack_surface', 'lockdown', 'EFI_TEST', 'is not set')] # refers to LOCKDOWN
571 l += [KconfigCheck('cut_attack_surface', 'lockdown', 'BPF_SYSCALL', 'is not set')] # refers to LOCKDOWN
572 l += [KconfigCheck('cut_attack_surface', 'lockdown', 'MMIOTRACE_TEST', 'is not set')] # refers to LOCKDOWN
573 l += [KconfigCheck('cut_attack_surface', 'lockdown', 'KPROBES', 'is not set')] # refers to LOCKDOWN
575 # 'cut_attack_surface', 'my'
576 l += [OR(KconfigCheck('cut_attack_surface', 'my', 'TRIM_UNUSED_KSYMS', 'y'),
578 l += [KconfigCheck('cut_attack_surface', 'my', 'MMIOTRACE', 'is not set')] # refers to LOCKDOWN (permissive)
579 l += [KconfigCheck('cut_attack_surface', 'my', 'LIVEPATCH', 'is not set')]
580 l += [KconfigCheck('cut_attack_surface', 'my', 'IP_DCCP', 'is not set')]
581 l += [KconfigCheck('cut_attack_surface', 'my', 'IP_SCTP', 'is not set')]
582 l += [KconfigCheck('cut_attack_surface', 'my', 'FTRACE', 'is not set')] # refers to LOCKDOWN
583 l += [KconfigCheck('cut_attack_surface', 'my', 'VIDEO_VIVID', 'is not set')]
584 l += [KconfigCheck('cut_attack_surface', 'my', 'INPUT_EVBUG', 'is not set')] # Can be used as a keylogger
587 if arch in ('X86_64', 'ARM64', 'X86_32'):
588 l += [KconfigCheck('harden_userspace', 'defconfig', 'INTEGRITY', 'y')]
590 l += [KconfigCheck('harden_userspace', 'my', 'INTEGRITY', 'y')]
592 l += [KconfigCheck('harden_userspace', 'defconfig', 'ARM64_MTE', 'y')]
593 if arch in ('ARM', 'X86_32'):
594 l += [KconfigCheck('harden_userspace', 'defconfig', 'VMSPLIT_3G', 'y')]
595 if arch in ('X86_64', 'ARM64'):
596 l += [KconfigCheck('harden_userspace', 'clipos', 'ARCH_MMAP_RND_BITS', '32')]
597 if arch in ('X86_32', 'ARM'):
598 l += [KconfigCheck('harden_userspace', 'my', 'ARCH_MMAP_RND_BITS', '16')]
600 # l += [KconfigCheck('feature_test', 'my', 'LKDTM', 'm')] # only for debugging!
603 def print_unknown_options(checklist, parsed_options):
605 for opt in checklist:
606 if hasattr(opt, 'opts'):
608 if hasattr(o, 'name'):
609 known_options.append(o.name)
611 known_options.append(opt.name)
612 for option, value in parsed_options.items():
613 if option not in known_options:
614 print('[?] No rule for option {} ({})'.format(option, value))
617 def print_checklist(mode, checklist, with_results):
621 opt = ['CONFIG_'+o.name, o.expected, o.decision, o.reason]
625 print(json.dumps(opts))
632 print('=' * sep_line_len)
633 print('{:^40}|{:^11}|{:^10}|{:^18}'.format('kconfig option name', 'desired val', 'decision', 'reason'), end='')
635 print('| {}'.format('check result'), end='')
637 print('=' * sep_line_len)
640 for opt in checklist:
642 if mode == 'show_ok':
643 if not opt.result.startswith('OK'):
645 if mode == 'show_fail':
646 if not opt.result.startswith('FAIL'):
648 opt.table_print(mode, with_results)
650 if mode == 'verbose':
651 print('-' * sep_line_len)
656 fail_count = len(list(filter(lambda opt: opt.result.startswith('FAIL'), checklist)))
658 ok_count = len(list(filter(lambda opt: opt.result.startswith('OK'), checklist)))
660 if mode == 'show_ok':
661 fail_suppressed = ' (suppressed in output)'
662 if mode == 'show_fail':
663 ok_suppressed = ' (suppressed in output)'
665 print('[+] Config check is finished: \'OK\' - {}{} / \'FAIL\' - {}{}'.format(ok_count, ok_suppressed, fail_count, fail_suppressed))
668 def perform_check(opt, parsed_options, kernel_version):
669 if hasattr(opt, 'opts'):
670 # prepare ComplexOptCheck
672 if hasattr(o, 'opts'):
673 # Recursion for nested ComplexOptChecks
674 perform_check(o, parsed_options, kernel_version)
675 if hasattr(o, 'state'):
676 o.state = parsed_options.get(o.name, None)
677 if hasattr(o, 'ver'):
678 o.ver = kernel_version
680 # prepare simple check, opt.state is mandatory
681 if not hasattr(opt, 'state'):
682 sys.exit('[!] ERROR: bad simple check {}'.format(vars(opt)))
683 opt.state = parsed_options.get(opt.name, None)
687 def perform_checks(checklist, parsed_options, kernel_version):
688 for opt in checklist:
689 perform_check(opt, parsed_options, kernel_version)
692 def parse_config_file(parsed_options, fname):
693 with open(fname, 'r') as f:
694 opt_is_on = re.compile("CONFIG_[a-zA-Z0-9_]*=[a-zA-Z0-9_\"]*")
695 opt_is_off = re.compile("# CONFIG_[a-zA-Z0-9_]* is not set")
697 for line in f.readlines():
702 if opt_is_on.match(line):
703 option, value = line[7:].split('=', 1)
704 elif opt_is_off.match(line):
705 option, value = line[9:].split(' ', 1)
706 if value != 'is not set':
707 sys.exit('[!] ERROR: bad disabled config option "{}"'.format(line))
709 if option in parsed_options:
710 sys.exit('[!] ERROR: config option "{}" exists multiple times'.format(line))
713 parsed_options[option] = value
715 return parsed_options
721 # - reporting about unknown kernel options in the config
722 # - verbose printing of ComplexOptCheck items
723 # * json mode for printing the results in JSON format
724 report_modes = ['verbose', 'json', 'show_ok', 'show_fail']
725 supported_archs = ['X86_64', 'X86_32', 'ARM64', 'ARM']
726 parser = ArgumentParser(prog='kconfig-hardened-check',
727 description='A tool for checking the security hardening options of the Linux kernel')
728 parser.add_argument('--version', action='version', version='%(prog)s ' + __version__)
729 parser.add_argument('-p', '--print', choices=supported_archs,
730 help='print security hardening preferences for the selected architecture')
731 parser.add_argument('-c', '--config',
732 help='check the kernel config file against these preferences')
733 parser.add_argument('-m', '--mode', choices=report_modes,
734 help='choose the report mode')
735 args = parser.parse_args()
741 print("[+] Special report mode: {}".format(mode))
743 config_checklist = []
747 print('[+] Config file to check: {}'.format(args.config))
749 arch, msg = detect_arch(args.config, supported_archs)
751 sys.exit('[!] ERROR: {}'.format(msg))
753 print('[+] Detected architecture: {}'.format(arch))
755 kernel_version, msg = detect_version(args.config)
756 if not kernel_version:
757 sys.exit('[!] ERROR: {}'.format(msg))
759 print('[+] Detected kernel version: {}.{}'.format(kernel_version[0], kernel_version[1]))
761 construct_checklist(config_checklist, arch)
762 parsed_options = OrderedDict()
763 parse_config_file(parsed_options, args.config)
764 perform_checks(config_checklist, parsed_options, kernel_version)
766 if mode == 'verbose':
767 print_unknown_options(config_checklist, parsed_options)
768 print_checklist(mode, config_checklist, True)
773 if mode in ('show_ok', 'show_fail'):
774 sys.exit('[!] ERROR: please use "{}" mode for checking the kernel config'.format(mode))
776 construct_checklist(config_checklist, arch)
778 print('[+] Printing kernel security hardening preferences for {}...'.format(arch))
779 print_checklist(mode, config_checklist, False)
785 if __name__ == '__main__':