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'):
109 def table_print(self, _mode, with_results):
110 print('CONFIG_{:<38}|{:^13}|{:^10}|{:^20}'.format(self.name, self.expected, self.decision, self.reason), end='')
112 print('| {}'.format(self.result), end='')
116 def __init__(self, ver_expected):
117 self.ver_expected = ver_expected
122 if self.ver[0] > self.ver_expected[0]:
123 self.result = 'OK: version >= ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
125 if self.ver[0] < self.ver_expected[0]:
126 self.result = 'FAIL: version < ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
128 if self.ver[1] >= self.ver_expected[1]:
129 self.result = 'OK: version >= ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
131 self.result = 'FAIL: version < ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
134 def table_print(self, _mode, with_results):
135 ver_req = 'kernel version >= ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
136 print('{:<91}'.format(ver_req), end='')
138 print('| {}'.format(self.result), end='')
142 def __init__(self, name):
148 if self.state is None:
149 self.result = 'FAIL: not present'
151 self.result = 'OK: is present'
154 def table_print(self, _mode, with_results):
155 print('CONFIG_{:<84}'.format(self.name + ' is present'), end='')
157 print('| {}'.format(self.result), end='')
160 class ComplexOptCheck:
161 def __init__(self, *opts):
164 sys.exit('[!] ERROR: empty {} check'.format(self.__class__.__name__))
165 if not isinstance(opts[0], OptCheck):
166 sys.exit('[!] ERROR: invalid {} check: {}'.format(self.__class__.__name__, opts))
171 return self.opts[0].name
175 return self.opts[0].expected
179 return self.opts[0].decision
183 return self.opts[0].reason
185 def table_print(self, mode, with_results):
186 if mode == 'verbose':
187 print(' {:87}'.format('<<< ' + self.__class__.__name__ + ' >>>'), end='')
189 print('| {}'.format(self.result), end='')
192 o.table_print(mode, with_results)
195 o.table_print(mode, False)
197 print('| {}'.format(self.result), end='')
200 class OR(ComplexOptCheck):
201 # self.opts[0] is the option that this OR-check is about.
203 # OR(<X_is_hardened>, <X_is_disabled>)
204 # OR(<X_is_hardened>, <old_X_is_hardened>)
208 sys.exit('[!] ERROR: invalid OR check')
210 for i, opt in enumerate(self.opts):
213 if opt.result != 'OK' or i == 0:
214 # Preserve additional explanation of this OK result.
215 # Simple OK is enough only for the main option that
216 # this OR-check is about.
217 self.result = opt.result
219 # Simple OK is not enough for additional checks.
220 self.result = 'OK: CONFIG_{} "{}"'.format(opt.name, opt.expected)
222 self.result = self.opts[0].result
226 class AND(ComplexOptCheck):
227 # self.opts[0] is the option that this AND-check is about.
229 # AND(<suboption>, <main_option>)
230 # Suboption is not checked if checking of the main_option is failed.
231 # AND(<X_is_disabled>, <old_X_is_disabled>)
234 for i, opt in reversed(list(enumerate(self.opts))):
237 self.result = opt.result
240 # This FAIL is caused by additional checks,
241 # and not by the main option that this AND-check is about.
242 # Describe the reason of the FAIL.
243 if opt.result.startswith('FAIL: \"') or opt.result == 'FAIL: not found':
244 self.result = 'FAIL: CONFIG_{} not "{}"'.format(opt.name, opt.expected)
245 elif opt.result == 'FAIL: not present':
246 self.result = 'FAIL: CONFIG_{} not present'.format(opt.name)
248 # This FAIL message is self-explaining.
249 self.result = opt.result
252 sys.exit('[!] ERROR: invalid AND check')
255 def detect_arch(fname, archs):
256 with open(fname, 'r') as f:
257 arch_pattern = re.compile("CONFIG_[a-zA-Z0-9_]*=y")
259 for line in f.readlines():
260 if arch_pattern.match(line):
261 option, _ = line[7:].split('=', 1)
266 return None, 'more than one supported architecture is detected'
268 return None, 'failed to detect architecture'
272 def detect_version(fname):
273 with open(fname, 'r') as f:
274 ver_pattern = re.compile("# Linux/.* Kernel Configuration")
275 for line in f.readlines():
276 if ver_pattern.match(line):
280 ver_numbers = ver_str.split('.')
281 if len(ver_numbers) < 3 or not ver_numbers[0].isdigit() or not ver_numbers[1].isdigit():
282 msg = 'failed to parse the version "' + ver_str + '"'
284 return (int(ver_numbers[0]), int(ver_numbers[1])), None
285 return None, 'no kernel version detected'
288 def construct_checklist(l, arch):
289 # Calling the OptCheck class constructor:
290 # OptCheck(reason, decision, name, expected)
292 modules_not_set = OptCheck('cut_attack_surface', 'kspp', 'MODULES', 'is not set')
293 devmem_not_set = OptCheck('cut_attack_surface', 'kspp', 'DEVMEM', 'is not set') # refers to LOCKDOWN
295 # 'self_protection', 'defconfig'
296 l += [OptCheck('self_protection', 'defconfig', 'BUG', 'y')]
297 l += [OptCheck('self_protection', 'defconfig', 'SLUB_DEBUG', 'y')]
298 l += [OptCheck('self_protection', 'defconfig', 'GCC_PLUGINS', 'y')]
299 l += [OR(OptCheck('self_protection', 'defconfig', 'STACKPROTECTOR_STRONG', 'y'),
300 OptCheck('self_protection', 'defconfig', 'CC_STACKPROTECTOR_STRONG', 'y'))]
301 l += [OR(OptCheck('self_protection', 'defconfig', 'STRICT_KERNEL_RWX', 'y'),
302 OptCheck('self_protection', 'defconfig', 'DEBUG_RODATA', 'y'))] # before v4.11
303 l += [OR(OptCheck('self_protection', 'defconfig', 'STRICT_MODULE_RWX', 'y'),
304 OptCheck('self_protection', 'defconfig', 'DEBUG_SET_MODULE_RONX', 'y'),
305 modules_not_set)] # DEBUG_SET_MODULE_RONX was before v4.11
306 l += [OR(OptCheck('self_protection', 'defconfig', 'REFCOUNT_FULL', 'y'),
307 VerCheck((5, 5)))] # REFCOUNT_FULL is enabled by default since v5.5
308 iommu_support_is_set = OptCheck('self_protection', 'defconfig', 'IOMMU_SUPPORT', 'y')
309 l += [iommu_support_is_set] # is needed for mitigating DMA attacks
310 if arch in ('X86_64', 'ARM64', 'X86_32'):
311 l += [OptCheck('self_protection', 'defconfig', 'RANDOMIZE_BASE', 'y')]
312 l += [OptCheck('self_protection', 'defconfig', 'THREAD_INFO_IN_TASK', 'y')]
313 if arch in ('X86_64', 'ARM64'):
314 l += [OptCheck('self_protection', 'defconfig', 'VMAP_STACK', 'y')]
315 if arch in ('X86_64', 'X86_32'):
316 l += [OptCheck('self_protection', 'defconfig', 'MICROCODE', 'y')] # is needed for mitigating CPU bugs
317 l += [OptCheck('self_protection', 'defconfig', 'RETPOLINE', 'y')]
318 l += [OptCheck('self_protection', 'defconfig', 'X86_SMAP', 'y')]
319 l += [OptCheck('self_protection', 'defconfig', 'SYN_COOKIES', 'y')] # another reason?
320 l += [OR(OptCheck('self_protection', 'defconfig', 'X86_UMIP', 'y'),
321 OptCheck('self_protection', 'defconfig', 'X86_INTEL_UMIP', 'y'))]
322 if arch in ('ARM64', 'ARM'):
323 l += [OptCheck('self_protection', 'defconfig', 'STACKPROTECTOR_PER_TASK', 'y')]
325 l += [OptCheck('self_protection', 'defconfig', 'PAGE_TABLE_ISOLATION', 'y')]
326 l += [OptCheck('self_protection', 'defconfig', 'RANDOMIZE_MEMORY', 'y')]
327 l += [AND(OptCheck('self_protection', 'defconfig', 'INTEL_IOMMU', 'y'),
328 iommu_support_is_set)]
329 l += [AND(OptCheck('self_protection', 'defconfig', 'AMD_IOMMU', 'y'),
330 iommu_support_is_set)]
332 l += [OptCheck('self_protection', 'defconfig', 'ARM64_PAN', 'y')]
333 l += [OptCheck('self_protection', 'defconfig', 'ARM64_EPAN', 'y')]
334 l += [OptCheck('self_protection', 'defconfig', 'UNMAP_KERNEL_AT_EL0', 'y')]
335 l += [OR(OptCheck('self_protection', 'defconfig', 'HARDEN_EL2_VECTORS', 'y'),
336 AND(OptCheck('self_protection', 'defconfig', 'RANDOMIZE_BASE', 'y'),
337 VerCheck((5, 9))))] # HARDEN_EL2_VECTORS was included in RANDOMIZE_BASE in v5.9
338 l += [OptCheck('self_protection', 'defconfig', 'RODATA_FULL_DEFAULT_ENABLED', 'y')]
339 l += [OptCheck('self_protection', 'defconfig', 'ARM64_PTR_AUTH_KERNEL', 'y')]
340 l += [OptCheck('self_protection', 'defconfig', 'ARM64_BTI_KERNEL', 'y')]
341 l += [OR(OptCheck('self_protection', 'defconfig', 'HARDEN_BRANCH_PREDICTOR', 'y'),
342 VerCheck((5, 10)))] # HARDEN_BRANCH_PREDICTOR is enabled by default since v5.10
343 l += [OptCheck('self_protection', 'defconfig', 'ARM64_MTE', 'y')]
345 l += [OptCheck('self_protection', 'defconfig', 'CPU_SW_DOMAIN_PAN', 'y')]
346 l += [OptCheck('self_protection', 'defconfig', 'HARDEN_BRANCH_PREDICTOR', 'y')]
348 # 'self_protection', 'kspp'
349 l += [OptCheck('self_protection', 'kspp', 'SECURITY_DMESG_RESTRICT', 'y')]
350 l += [OptCheck('self_protection', 'kspp', 'BUG_ON_DATA_CORRUPTION', 'y')]
351 l += [OptCheck('self_protection', 'kspp', 'DEBUG_WX', 'y')]
352 l += [OptCheck('self_protection', 'kspp', 'SCHED_STACK_END_CHECK', 'y')]
353 l += [OptCheck('self_protection', 'kspp', 'SLAB_FREELIST_HARDENED', 'y')]
354 l += [OptCheck('self_protection', 'kspp', 'SLAB_FREELIST_RANDOM', 'y')]
355 l += [OptCheck('self_protection', 'kspp', 'SHUFFLE_PAGE_ALLOCATOR', 'y')]
356 l += [OptCheck('self_protection', 'kspp', 'FORTIFY_SOURCE', 'y')]
357 l += [OptCheck('self_protection', 'kspp', 'DEBUG_LIST', 'y')]
358 l += [OptCheck('self_protection', 'kspp', 'DEBUG_SG', 'y')]
359 l += [OptCheck('self_protection', 'kspp', 'DEBUG_CREDENTIALS', 'y')]
360 l += [OptCheck('self_protection', 'kspp', 'DEBUG_NOTIFIERS', 'y')]
361 l += [OptCheck('self_protection', 'kspp', 'INIT_ON_ALLOC_DEFAULT_ON', 'y')]
362 l += [OptCheck('self_protection', 'kspp', 'GCC_PLUGIN_LATENT_ENTROPY', 'y')]
363 randstruct_is_set = OptCheck('self_protection', 'kspp', 'GCC_PLUGIN_RANDSTRUCT', 'y')
364 l += [randstruct_is_set]
365 hardened_usercopy_is_set = OptCheck('self_protection', 'kspp', 'HARDENED_USERCOPY', 'y')
366 l += [hardened_usercopy_is_set]
367 l += [AND(OptCheck('self_protection', 'kspp', 'HARDENED_USERCOPY_FALLBACK', 'is not set'),
368 hardened_usercopy_is_set)]
369 l += [AND(OptCheck('self_protection', 'kspp', 'HARDENED_USERCOPY_PAGESPAN', 'is not set'),
370 hardened_usercopy_is_set)]
371 l += [OR(OptCheck('self_protection', 'kspp', 'MODULE_SIG', 'y'),
373 l += [OR(OptCheck('self_protection', 'kspp', 'MODULE_SIG_ALL', 'y'),
375 l += [OR(OptCheck('self_protection', 'kspp', 'MODULE_SIG_SHA512', 'y'),
377 l += [OR(OptCheck('self_protection', 'kspp', 'MODULE_SIG_FORCE', 'y'),
378 modules_not_set)] # refers to LOCKDOWN
379 l += [OR(OptCheck('self_protection', 'kspp', 'INIT_STACK_ALL_ZERO', 'y'),
380 OptCheck('self_protection', 'kspp', 'GCC_PLUGIN_STRUCTLEAK_BYREF_ALL', 'y'))]
381 l += [OR(OptCheck('self_protection', 'kspp', 'INIT_ON_FREE_DEFAULT_ON', 'y'),
382 OptCheck('self_protection', 'kspp', 'PAGE_POISONING_ZERO', 'y'))]
383 # CONFIG_INIT_ON_FREE_DEFAULT_ON was added in v5.3.
384 # CONFIG_PAGE_POISONING_ZERO was removed in v5.11.
385 # Starting from v5.11 CONFIG_PAGE_POISONING unconditionally checks
386 # the 0xAA poison pattern on allocation.
387 # That brings higher performance penalty.
388 if arch in ('X86_64', 'ARM64', 'X86_32'):
389 stackleak_is_set = OptCheck('self_protection', 'kspp', 'GCC_PLUGIN_STACKLEAK', 'y')
390 l += [stackleak_is_set]
391 l += [OptCheck('self_protection', 'kspp', 'RANDOMIZE_KSTACK_OFFSET_DEFAULT', 'y')]
392 if arch in ('X86_64', 'X86_32'):
393 l += [OptCheck('self_protection', 'kspp', 'DEFAULT_MMAP_MIN_ADDR', '65536')]
394 if arch in ('ARM64', 'ARM'):
395 l += [OptCheck('self_protection', 'kspp', 'DEFAULT_MMAP_MIN_ADDR', '32768')]
396 l += [OptCheck('self_protection', 'kspp', 'SYN_COOKIES', 'y')] # another reason?
398 l += [OptCheck('self_protection', 'kspp', 'ARM64_SW_TTBR0_PAN', 'y')]
400 l += [OptCheck('self_protection', 'kspp', 'PAGE_TABLE_ISOLATION', 'y')]
401 l += [OptCheck('self_protection', 'kspp', 'HIGHMEM64G', 'y')]
402 l += [OptCheck('self_protection', 'kspp', 'X86_PAE', 'y')]
404 # 'self_protection', 'maintainer'
405 ubsan_bounds_is_set = OptCheck('self_protection', 'maintainer', 'UBSAN_BOUNDS', 'y') # only array index bounds checking
406 l += [ubsan_bounds_is_set] # recommended by Kees Cook in /issues/53
407 l += [AND(OptCheck('self_protection', 'maintainer', 'UBSAN_SANITIZE_ALL', 'y'),
408 ubsan_bounds_is_set)] # recommended by Kees Cook in /issues/53
409 l += [AND(OptCheck('self_protection', 'maintainer', 'UBSAN_TRAP', 'y'),
410 ubsan_bounds_is_set)] # recommended by Kees Cook in /issues/53
412 # 'self_protection', 'clipos'
413 l += [OptCheck('self_protection', 'clipos', 'DEBUG_VIRTUAL', 'y')]
414 l += [OptCheck('self_protection', 'clipos', 'STATIC_USERMODEHELPER', 'y')] # needs userspace support
415 l += [OptCheck('self_protection', 'clipos', 'EFI_DISABLE_PCI_DMA', 'y')]
416 l += [OptCheck('self_protection', 'clipos', 'SLAB_MERGE_DEFAULT', 'is not set')] # slab_nomerge
417 l += [OptCheck('self_protection', 'clipos', 'RANDOM_TRUST_BOOTLOADER', 'is not set')]
418 l += [OptCheck('self_protection', 'clipos', 'RANDOM_TRUST_CPU', 'is not set')]
419 l += [AND(OptCheck('self_protection', 'clipos', 'GCC_PLUGIN_RANDSTRUCT_PERFORMANCE', 'is not set'),
421 if arch in ('X86_64', 'ARM64', 'X86_32'):
422 l += [AND(OptCheck('self_protection', 'clipos', 'STACKLEAK_METRICS', 'is not set'),
424 l += [AND(OptCheck('self_protection', 'clipos', 'STACKLEAK_RUNTIME_DISABLE', 'is not set'),
426 if arch in ('X86_64', 'X86_32'):
427 l += [AND(OptCheck('self_protection', 'clipos', 'INTEL_IOMMU_DEFAULT_ON', 'y'),
428 iommu_support_is_set)]
430 l += [AND(OptCheck('self_protection', 'clipos', 'INTEL_IOMMU_SVM', 'y'),
431 iommu_support_is_set)]
433 l += [AND(OptCheck('self_protection', 'clipos', 'INTEL_IOMMU', 'y'),
434 iommu_support_is_set)]
436 # 'self_protection', 'my'
437 l += [OptCheck('self_protection', 'my', 'RESET_ATTACK_MITIGATION', 'y')] # needs userspace support (systemd)
439 l += [AND(OptCheck('self_protection', 'my', 'AMD_IOMMU_V2', 'y'),
440 iommu_support_is_set)]
442 l += [OptCheck('self_protection', 'my', 'SHADOW_CALL_STACK', 'y')] # depends on clang, maybe it's alternative to STACKPROTECTOR_STRONG
443 l += [OptCheck('self_protection', 'my', 'KASAN_HW_TAGS', 'y')]
444 cfi_clang_is_set = OptCheck('self_protection', 'my', 'CFI_CLANG', 'y')
445 l += [cfi_clang_is_set]
446 l += [AND(OptCheck('self_protection', 'my', 'CFI_PERMISSIVE', 'is not set'),
450 if arch in ('X86_64', 'ARM64', 'X86_32'):
451 l += [OptCheck('security_policy', 'defconfig', 'SECURITY', 'y')] # and choose your favourite LSM
453 l += [OptCheck('security_policy', 'kspp', 'SECURITY', 'y')] # and choose your favourite LSM
454 l += [OptCheck('security_policy', 'kspp', 'SECURITY_YAMA', 'y')]
455 l += [OR(OptCheck('security_policy', 'my', 'SECURITY_WRITABLE_HOOKS', 'is not set'),
456 OptCheck('security_policy', 'kspp', 'SECURITY_SELINUX_DISABLE', 'is not set'))]
457 l += [OptCheck('security_policy', 'clipos', 'SECURITY_LOCKDOWN_LSM', 'y')]
458 l += [OptCheck('security_policy', 'clipos', 'SECURITY_LOCKDOWN_LSM_EARLY', 'y')]
459 l += [OptCheck('security_policy', 'clipos', 'LOCK_DOWN_KERNEL_FORCE_CONFIDENTIALITY', 'y')]
460 l += [OptCheck('security_policy', 'my', 'SECURITY_SAFESETID', 'y')]
461 loadpin_is_set = OptCheck('security_policy', 'my', 'SECURITY_LOADPIN', 'y')
462 l += [loadpin_is_set] # needs userspace support
463 l += [AND(OptCheck('security_policy', 'my', 'SECURITY_LOADPIN_ENFORCE', 'y'),
466 # 'cut_attack_surface', 'defconfig'
467 l += [OptCheck('cut_attack_surface', 'defconfig', 'SECCOMP', 'y')]
468 l += [OptCheck('cut_attack_surface', 'defconfig', 'SECCOMP_FILTER', 'y')]
469 if arch in ('X86_64', 'ARM64', 'X86_32'):
470 l += [OR(OptCheck('cut_attack_surface', 'defconfig', 'STRICT_DEVMEM', 'y'),
471 devmem_not_set)] # refers to LOCKDOWN
473 # 'cut_attack_surface', 'kspp'
474 l += [OptCheck('cut_attack_surface', 'kspp', 'ACPI_CUSTOM_METHOD', 'is not set')] # refers to LOCKDOWN
475 l += [OptCheck('cut_attack_surface', 'kspp', 'COMPAT_BRK', 'is not set')]
476 l += [OptCheck('cut_attack_surface', 'kspp', 'DEVKMEM', 'is not set')] # refers to LOCKDOWN
477 l += [OptCheck('cut_attack_surface', 'kspp', 'COMPAT_VDSO', 'is not set')]
478 l += [OptCheck('cut_attack_surface', 'kspp', 'BINFMT_MISC', 'is not set')]
479 l += [OptCheck('cut_attack_surface', 'kspp', 'INET_DIAG', 'is not set')]
480 l += [OptCheck('cut_attack_surface', 'kspp', 'KEXEC', 'is not set')] # refers to LOCKDOWN
481 l += [OptCheck('cut_attack_surface', 'kspp', 'PROC_KCORE', 'is not set')] # refers to LOCKDOWN
482 l += [OptCheck('cut_attack_surface', 'kspp', 'LEGACY_PTYS', 'is not set')]
483 l += [OptCheck('cut_attack_surface', 'kspp', 'HIBERNATION', 'is not set')] # refers to LOCKDOWN
484 l += [OptCheck('cut_attack_surface', 'kspp', 'IA32_EMULATION', 'is not set')]
485 l += [OptCheck('cut_attack_surface', 'kspp', 'X86_X32', 'is not set')]
486 l += [OptCheck('cut_attack_surface', 'kspp', 'MODIFY_LDT_SYSCALL', 'is not set')]
487 l += [OptCheck('cut_attack_surface', 'kspp', 'OABI_COMPAT', 'is not set')]
488 l += [modules_not_set]
489 l += [devmem_not_set]
490 l += [OR(OptCheck('cut_attack_surface', 'kspp', 'IO_STRICT_DEVMEM', 'y'),
491 devmem_not_set)] # refers to LOCKDOWN
493 l += [OR(OptCheck('cut_attack_surface', 'kspp', 'STRICT_DEVMEM', 'y'),
494 devmem_not_set)] # refers to LOCKDOWN
496 l += [OptCheck('cut_attack_surface', 'kspp', 'LEGACY_VSYSCALL_NONE', 'y')] # 'vsyscall=none'
498 # 'cut_attack_surface', 'grsecurity'
499 l += [OptCheck('cut_attack_surface', 'grsecurity', 'ZSMALLOC_STAT', 'is not set')]
500 l += [OptCheck('cut_attack_surface', 'grsecurity', 'PAGE_OWNER', 'is not set')]
501 l += [OptCheck('cut_attack_surface', 'grsecurity', 'DEBUG_KMEMLEAK', 'is not set')]
502 l += [OptCheck('cut_attack_surface', 'grsecurity', 'BINFMT_AOUT', 'is not set')]
503 l += [OptCheck('cut_attack_surface', 'grsecurity', 'KPROBE_EVENTS', 'is not set')]
504 l += [OptCheck('cut_attack_surface', 'grsecurity', 'UPROBE_EVENTS', 'is not set')]
505 l += [OptCheck('cut_attack_surface', 'grsecurity', 'GENERIC_TRACER', 'is not set')] # refers to LOCKDOWN
506 l += [OptCheck('cut_attack_surface', 'grsecurity', 'FUNCTION_TRACER', 'is not set')]
507 l += [OptCheck('cut_attack_surface', 'grsecurity', 'STACK_TRACER', 'is not set')]
508 l += [OptCheck('cut_attack_surface', 'grsecurity', 'HIST_TRIGGERS', 'is not set')]
509 l += [OptCheck('cut_attack_surface', 'grsecurity', 'BLK_DEV_IO_TRACE', 'is not set')]
510 l += [OptCheck('cut_attack_surface', 'grsecurity', 'PROC_VMCORE', 'is not set')]
511 l += [OptCheck('cut_attack_surface', 'grsecurity', 'PROC_PAGE_MONITOR', 'is not set')]
512 l += [OptCheck('cut_attack_surface', 'grsecurity', 'USELIB', 'is not set')]
513 l += [OptCheck('cut_attack_surface', 'grsecurity', 'CHECKPOINT_RESTORE', 'is not set')]
514 l += [OptCheck('cut_attack_surface', 'grsecurity', 'USERFAULTFD', 'is not set')]
515 l += [OptCheck('cut_attack_surface', 'grsecurity', 'HWPOISON_INJECT', 'is not set')]
516 l += [OptCheck('cut_attack_surface', 'grsecurity', 'MEM_SOFT_DIRTY', 'is not set')]
517 l += [OptCheck('cut_attack_surface', 'grsecurity', 'DEVPORT', 'is not set')] # refers to LOCKDOWN
518 l += [OptCheck('cut_attack_surface', 'grsecurity', 'DEBUG_FS', 'is not set')] # refers to LOCKDOWN
519 l += [OptCheck('cut_attack_surface', 'grsecurity', 'NOTIFIER_ERROR_INJECTION', 'is not set')]
520 l += [OptCheck('cut_attack_surface', 'grsecurity', 'FAIL_FUTEX', 'is not set')]
521 l += [OptCheck('cut_attack_surface', 'grsecurity', 'PUNIT_ATOM_DEBUG', 'is not set')]
522 l += [OptCheck('cut_attack_surface', 'grsecurity', 'ACPI_CONFIGFS', 'is not set')]
523 l += [OptCheck('cut_attack_surface', 'grsecurity', 'EDAC_DEBUG', 'is not set')]
524 l += [OptCheck('cut_attack_surface', 'grsecurity', 'DRM_I915_DEBUG', 'is not set')]
525 l += [OptCheck('cut_attack_surface', 'grsecurity', 'BCACHE_CLOSURES_DEBUG', 'is not set')]
526 l += [OptCheck('cut_attack_surface', 'grsecurity', 'DVB_C8SECTPFE', 'is not set')]
527 l += [OptCheck('cut_attack_surface', 'grsecurity', 'MTD_SLRAM', 'is not set')]
528 l += [OptCheck('cut_attack_surface', 'grsecurity', 'MTD_PHRAM', 'is not set')]
529 l += [OptCheck('cut_attack_surface', 'grsecurity', 'IO_URING', 'is not set')]
530 l += [OptCheck('cut_attack_surface', 'grsecurity', 'KCMP', 'is not set')]
531 l += [OptCheck('cut_attack_surface', 'grsecurity', 'RSEQ', 'is not set')]
532 l += [OptCheck('cut_attack_surface', 'grsecurity', 'LATENCYTOP', 'is not set')]
533 l += [OptCheck('cut_attack_surface', 'grsecurity', 'KCOV', 'is not set')]
534 l += [OptCheck('cut_attack_surface', 'grsecurity', 'PROVIDE_OHCI1394_DMA_INIT', 'is not set')]
535 l += [OptCheck('cut_attack_surface', 'grsecurity', 'SUNRPC_DEBUG', 'is not set')]
536 l += [AND(OptCheck('cut_attack_surface', 'grsecurity', 'PTDUMP_DEBUGFS', 'is not set'),
537 OptCheck('cut_attack_surface', 'grsecurity', 'X86_PTDUMP', 'is not set'))]
539 # 'cut_attack_surface', 'maintainer'
540 l += [OptCheck('cut_attack_surface', 'maintainer', 'DRM_LEGACY', 'is not set')] # recommended by Daniel Vetter in /issues/38
541 l += [OptCheck('cut_attack_surface', 'maintainer', 'FB', 'is not set')] # recommended by Daniel Vetter in /issues/38
542 l += [OptCheck('cut_attack_surface', 'maintainer', 'VT', 'is not set')] # recommended by Daniel Vetter in /issues/38
543 l += [OptCheck('cut_attack_surface', 'maintainer', 'BLK_DEV_FD', 'is not set')] # recommended by Denis Efremov in /pull/54
545 # 'cut_attack_surface', 'grapheneos'
546 l += [OptCheck('cut_attack_surface', 'grapheneos', 'AIO', 'is not set')]
548 # 'cut_attack_surface', 'clipos'
549 l += [OptCheck('cut_attack_surface', 'clipos', 'STAGING', 'is not set')]
550 l += [OptCheck('cut_attack_surface', 'clipos', 'KSM', 'is not set')] # to prevent FLUSH+RELOAD attack
551 # l += [OptCheck('cut_attack_surface', 'clipos', 'IKCONFIG', 'is not set')] # no, IKCONFIG is needed for this check :)
552 l += [OptCheck('cut_attack_surface', 'clipos', 'KALLSYMS', 'is not set')]
553 l += [OptCheck('cut_attack_surface', 'clipos', 'X86_VSYSCALL_EMULATION', 'is not set')]
554 l += [OptCheck('cut_attack_surface', 'clipos', 'MAGIC_SYSRQ', 'is not set')]
555 l += [OptCheck('cut_attack_surface', 'clipos', 'KEXEC_FILE', 'is not set')] # refers to LOCKDOWN (permissive)
556 l += [OptCheck('cut_attack_surface', 'clipos', 'USER_NS', 'is not set')] # user.max_user_namespaces=0
557 l += [OptCheck('cut_attack_surface', 'clipos', 'X86_MSR', 'is not set')] # refers to LOCKDOWN
558 l += [OptCheck('cut_attack_surface', 'clipos', 'X86_CPUID', 'is not set')]
559 l += [OptCheck('cut_attack_surface', 'clipos', 'X86_IOPL_IOPERM', 'is not set')] # refers to LOCKDOWN
560 l += [OptCheck('cut_attack_surface', 'clipos', 'ACPI_TABLE_UPGRADE', 'is not set')] # refers to LOCKDOWN
561 l += [OptCheck('cut_attack_surface', 'clipos', 'EFI_CUSTOM_SSDT_OVERLAYS', 'is not set')]
562 l += [AND(OptCheck('cut_attack_surface', 'clipos', 'LDISC_AUTOLOAD', 'is not set'),
563 PresenceCheck('LDISC_AUTOLOAD'))]
564 if arch in ('X86_64', 'X86_32'):
565 l += [OptCheck('cut_attack_surface', 'clipos', 'X86_INTEL_TSX_MODE_OFF', 'y')] # tsx=off
567 # 'cut_attack_surface', 'lockdown'
568 l += [OptCheck('cut_attack_surface', 'lockdown', 'EFI_TEST', 'is not set')] # refers to LOCKDOWN
569 l += [OptCheck('cut_attack_surface', 'lockdown', 'BPF_SYSCALL', 'is not set')] # refers to LOCKDOWN
570 l += [OptCheck('cut_attack_surface', 'lockdown', 'MMIOTRACE_TEST', 'is not set')] # refers to LOCKDOWN
571 l += [OptCheck('cut_attack_surface', 'lockdown', 'KPROBES', 'is not set')] # refers to LOCKDOWN
573 # 'cut_attack_surface', 'my'
574 l += [OR(OptCheck('cut_attack_surface', 'my', 'TRIM_UNUSED_KSYMS', 'y'),
576 l += [OptCheck('cut_attack_surface', 'my', 'MMIOTRACE', 'is not set')] # refers to LOCKDOWN (permissive)
577 l += [OptCheck('cut_attack_surface', 'my', 'LIVEPATCH', 'is not set')]
578 l += [OptCheck('cut_attack_surface', 'my', 'IP_DCCP', 'is not set')]
579 l += [OptCheck('cut_attack_surface', 'my', 'IP_SCTP', 'is not set')]
580 l += [OptCheck('cut_attack_surface', 'my', 'FTRACE', 'is not set')] # refers to LOCKDOWN
581 l += [OptCheck('cut_attack_surface', 'my', 'VIDEO_VIVID', 'is not set')]
582 l += [OptCheck('cut_attack_surface', 'my', 'INPUT_EVBUG', 'is not set')] # Can be used as a keylogger
584 # 'userspace_hardening'
585 if arch in ('X86_64', 'ARM64', 'X86_32'):
586 l += [OptCheck('userspace_hardening', 'defconfig', 'INTEGRITY', 'y')]
588 l += [OptCheck('userspace_hardening', 'my', 'INTEGRITY', 'y')]
590 l += [OptCheck('userspace_hardening', 'defconfig', 'ARM64_MTE', 'y')]
591 if arch in ('ARM', 'X86_32'):
592 l += [OptCheck('userspace_hardening', 'defconfig', 'VMSPLIT_3G', 'y')]
593 if arch in ('X86_64', 'ARM64'):
594 l += [OptCheck('userspace_hardening', 'clipos', 'ARCH_MMAP_RND_BITS', '32')]
595 if arch in ('X86_32', 'ARM'):
596 l += [OptCheck('userspace_hardening', 'my', 'ARCH_MMAP_RND_BITS', '16')]
598 # l += [OptCheck('feature_test', 'my', 'LKDTM', 'm')] # only for debugging!
601 def print_unknown_options(checklist, parsed_options):
603 for opt in checklist:
604 if hasattr(opt, 'opts'):
606 if hasattr(o, 'name'):
607 known_options.append(o.name)
609 known_options.append(opt.name)
610 for option, value in parsed_options.items():
611 if option not in known_options:
612 print('[?] No rule for option {} ({})'.format(option, value))
615 def print_checklist(mode, checklist, with_results):
619 opt = ['CONFIG_'+o.name, o.expected, o.decision, o.reason]
623 print(json.dumps(opts))
630 print('=' * sep_line_len)
631 print('{:^45}|{:^13}|{:^10}|{:^20}'.format('option name', 'desired val', 'decision', 'reason'), end='')
633 print('| {}'.format('check result'), end='')
635 print('=' * sep_line_len)
638 for opt in checklist:
640 if mode == 'show_ok':
641 if not opt.result.startswith('OK'):
643 if mode == 'show_fail':
644 if not opt.result.startswith('FAIL'):
646 opt.table_print(mode, with_results)
648 if mode == 'verbose':
649 print('-' * sep_line_len)
654 fail_count = len(list(filter(lambda opt: opt.result.startswith('FAIL'), checklist)))
656 ok_count = len(list(filter(lambda opt: opt.result.startswith('OK'), checklist)))
658 if mode == 'show_ok':
659 fail_suppressed = ' (suppressed in output)'
660 if mode == 'show_fail':
661 ok_suppressed = ' (suppressed in output)'
663 print('[+] Config check is finished: \'OK\' - {}{} / \'FAIL\' - {}{}'.format(ok_count, ok_suppressed, fail_count, fail_suppressed))
666 def perform_check(opt, parsed_options, kernel_version):
667 if hasattr(opt, 'opts'):
668 # prepare ComplexOptCheck
670 if hasattr(o, 'opts'):
671 # Recursion for nested ComplexOptChecks
672 perform_check(o, parsed_options, kernel_version)
673 if hasattr(o, 'state'):
674 o.state = parsed_options.get(o.name, None)
675 if hasattr(o, 'ver'):
676 o.ver = kernel_version
678 # prepare simple check, opt.state is mandatory
679 if not hasattr(opt, 'state'):
680 sys.exit('[!] ERROR: bad simple check {}'.format(vars(opt)))
681 opt.state = parsed_options.get(opt.name, None)
685 def perform_checks(checklist, parsed_options, kernel_version):
686 for opt in checklist:
687 perform_check(opt, parsed_options, kernel_version)
690 def parse_config_file(parsed_options, fname):
691 with open(fname, 'r') as f:
692 opt_is_on = re.compile("CONFIG_[a-zA-Z0-9_]*=[a-zA-Z0-9_\"]*")
693 opt_is_off = re.compile("# CONFIG_[a-zA-Z0-9_]* is not set")
695 for line in f.readlines():
700 if opt_is_on.match(line):
701 option, value = line[7:].split('=', 1)
702 elif opt_is_off.match(line):
703 option, value = line[9:].split(' ', 1)
704 if value != 'is not set':
705 sys.exit('[!] ERROR: bad disabled config option "{}"'.format(line))
707 if option in parsed_options:
708 sys.exit('[!] ERROR: config option "{}" exists multiple times'.format(line))
711 parsed_options[option] = value
713 return parsed_options
719 # - reporting about unknown kernel options in the config
720 # - verbose printing of ComplexOptCheck items
721 # * json mode for printing the results in JSON format
722 report_modes = ['verbose', 'json', 'show_ok', 'show_fail']
723 supported_archs = ['X86_64', 'X86_32', 'ARM64', 'ARM']
724 parser = ArgumentParser(prog='kconfig-hardened-check',
725 description='A tool for checking the security hardening options of the Linux kernel')
726 parser.add_argument('--version', action='version', version='%(prog)s ' + __version__)
727 parser.add_argument('-p', '--print', choices=supported_archs,
728 help='print security hardening preferences for the selected architecture')
729 parser.add_argument('-c', '--config',
730 help='check the kernel config file against these preferences')
731 parser.add_argument('-m', '--mode', choices=report_modes,
732 help='choose the report mode')
733 args = parser.parse_args()
739 print("[+] Special report mode: {}".format(mode))
741 config_checklist = []
745 print('[+] Config file to check: {}'.format(args.config))
747 arch, msg = detect_arch(args.config, supported_archs)
749 sys.exit('[!] ERROR: {}'.format(msg))
751 print('[+] Detected architecture: {}'.format(arch))
753 kernel_version, msg = detect_version(args.config)
754 if not kernel_version:
755 sys.exit('[!] ERROR: {}'.format(msg))
757 print('[+] Detected kernel version: {}.{}'.format(kernel_version[0], kernel_version[1]))
759 construct_checklist(config_checklist, arch)
760 parsed_options = OrderedDict()
761 parse_config_file(parsed_options, args.config)
762 perform_checks(config_checklist, parsed_options, kernel_version)
764 if mode == 'verbose':
765 print_unknown_options(config_checklist, parsed_options)
766 print_checklist(mode, config_checklist, True)
771 if mode in ('show_ok', 'show_fail'):
772 sys.exit('[!] ERROR: please use "{}" mode for checking the kernel config'.format(mode))
774 construct_checklist(config_checklist, arch)
776 print('[+] Printing kernel security hardening preferences for {}...'.format(arch))
777 print_checklist(mode, config_checklist, False)
783 if __name__ == '__main__':