4 # This tool helps me to check the Linux kernel Kconfig option list
5 # against my 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:
16 # page_alloc.shuffle=1
17 # iommu=force (does it help against DMA attacks?)
18 # page_poison=1 (if enabled)
23 # Mitigations of CPU vulnerabilities:
25 # mitigations=auto,nosmt
29 # spec_store_bypass_disable=on
37 # N.B. Hardening sysctls:
38 # kernel.kptr_restrict=2
39 # kernel.dmesg_restrict=1
40 # kernel.perf_event_paranoid=3
41 # kernel.kexec_load_disabled=1
42 # kernel.yama.ptrace_scope=3
43 # user.max_user_namespaces=0
44 # what about bpf_jit_enable?
45 # kernel.unprivileged_bpf_disabled=1
46 # net.core.bpf_jit_harden=2
48 # vm.unprivileged_userfaultfd=0
50 # dev.tty.ldisc_autoload=0
51 # fs.protected_symlinks=1
52 # fs.protected_hardlinks=1
53 # fs.protected_fifos=2
54 # fs.protected_regular=2
56 # kernel.modules_disabled=1
59 # pylint: disable=missing-module-docstring,missing-class-docstring,missing-function-docstring
60 # pylint: disable=line-too-long,invalid-name,too-many-branches,too-many-statements
64 from argparse import ArgumentParser
65 from collections import OrderedDict
68 from .__about__ import __version__
72 def __init__(self, reason, decision, name, expected):
74 self.expected = expected
75 self.decision = decision
81 if self.expected == self.state:
83 elif self.state is None:
84 if self.expected == 'is not set':
85 self.result = 'OK: not found'
87 self.result = 'FAIL: not found'
89 self.result = 'FAIL: "' + self.state + '"'
91 if self.result.startswith('OK'):
95 def table_print(self, _mode, with_results):
96 print('CONFIG_{:<38}|{:^13}|{:^10}|{:^20}'.format(self.name, self.expected, self.decision, self.reason), end='')
98 print('| {}'.format(self.result), end='')
102 def __init__(self, ver_expected):
103 self.ver_expected = ver_expected
108 if self.ver[0] > self.ver_expected[0]:
109 self.result = 'OK: version >= ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
111 if self.ver[0] < self.ver_expected[0]:
112 self.result = 'FAIL: version < ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
114 if self.ver[1] >= self.ver_expected[1]:
115 self.result = 'OK: version >= ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
117 self.result = 'FAIL: version < ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
120 def table_print(self, _mode, with_results):
121 ver_req = 'kernel version >= ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
122 print('{:<91}'.format(ver_req), end='')
124 print('| {}'.format(self.result), end='')
128 def __init__(self, name):
134 if self.state is None:
135 self.result = 'FAIL: not present'
137 self.result = 'OK: is present'
140 def table_print(self, _mode, with_results):
141 print('CONFIG_{:<84}'.format(self.name + ' is present'), end='')
143 print('| {}'.format(self.result), end='')
146 class ComplexOptCheck:
147 def __init__(self, *opts):
150 sys.exit('[!] ERROR: empty {} check'.format(self.__class__.__name__))
151 if not isinstance(opts[0], OptCheck):
152 sys.exit('[!] ERROR: invalid {} check: {}'.format(self.__class__.__name__, opts))
157 return self.opts[0].name
161 return self.opts[0].expected
165 return self.opts[0].decision
169 return self.opts[0].reason
171 def table_print(self, mode, with_results):
172 if mode == 'verbose':
173 print(' {:87}'.format('<<< ' + self.__class__.__name__ + ' >>>'), end='')
175 print('| {}'.format(self.result), end='')
178 o.table_print(mode, with_results)
181 o.table_print(mode, False)
183 print('| {}'.format(self.result), end='')
186 class OR(ComplexOptCheck):
187 # self.opts[0] is the option that this OR-check is about.
189 # OR(<X_is_hardened>, <X_is_disabled>)
190 # OR(<X_is_hardened>, <old_X_is_hardened>)
194 sys.exit('[!] ERROR: invalid OR check')
196 for i, opt in enumerate(self.opts):
199 if opt.result != 'OK' or i == 0:
200 # Preserve additional explanation of this OK result.
201 # Simple OK is enough only for the main option that
202 # this OR-check is about.
203 self.result = opt.result
205 # Simple OK is not enough for additional checks.
206 self.result = 'OK: CONFIG_{} "{}"'.format(opt.name, opt.expected)
208 self.result = self.opts[0].result
212 class AND(ComplexOptCheck):
213 # self.opts[0] is the option that this AND-check is about.
215 # AND(<suboption>, <main_option>)
216 # Suboption is not checked if checking of the main_option is failed.
217 # AND(<X_is_disabled>, <old_X_is_disabled>)
220 for i, opt in reversed(list(enumerate(self.opts))):
223 self.result = opt.result
226 # This FAIL is caused by additional checks,
227 # and not by the main option that this AND-check is about.
228 if opt.result.startswith('FAIL: \"'):
229 # Describe the reason of the FAIL.
230 self.result = 'FAIL: CONFIG_{} not "{}"'.format(opt.name, opt.expected)
232 # This FAIL message is self-explaining.
233 self.result = opt.result
236 sys.exit('[!] ERROR: invalid AND check')
239 def detect_arch(fname, archs):
240 with open(fname, 'r') as f:
241 arch_pattern = re.compile("CONFIG_[a-zA-Z0-9_]*=y")
243 for line in f.readlines():
244 if arch_pattern.match(line):
245 option, _ = line[7:].split('=', 1)
250 return None, 'more than one supported architecture is detected'
252 return None, 'failed to detect architecture'
256 def detect_version(fname):
257 with open(fname, 'r') as f:
258 ver_pattern = re.compile("# Linux/.* Kernel Configuration")
259 for line in f.readlines():
260 if ver_pattern.match(line):
264 ver_numbers = ver_str.split('.')
265 if len(ver_numbers) < 3 or not ver_numbers[0].isdigit() or not ver_numbers[1].isdigit():
266 msg = 'failed to parse the version "' + ver_str + '"'
268 return (int(ver_numbers[0]), int(ver_numbers[1])), None
269 return None, 'no kernel version detected'
272 def construct_checklist(l, arch):
273 modules_not_set = OptCheck('cut_attack_surface', 'kspp', 'MODULES', 'is not set')
274 devmem_not_set = OptCheck('cut_attack_surface', 'kspp', 'DEVMEM', 'is not set') # refers to LOCKDOWN
276 # 'self_protection', 'defconfig'
277 l += [OptCheck('self_protection', 'defconfig', 'BUG', 'y')]
278 l += [OptCheck('self_protection', 'defconfig', 'SLUB_DEBUG', 'y')]
279 l += [OptCheck('self_protection', 'defconfig', 'GCC_PLUGINS', 'y')]
280 l += [OR(OptCheck('self_protection', 'defconfig', 'STACKPROTECTOR_STRONG', 'y'),
281 OptCheck('self_protection', 'defconfig', 'CC_STACKPROTECTOR_STRONG', 'y'))]
282 l += [OR(OptCheck('self_protection', 'defconfig', 'STRICT_KERNEL_RWX', 'y'),
283 OptCheck('self_protection', 'defconfig', 'DEBUG_RODATA', 'y'))] # before v4.11
284 l += [OR(OptCheck('self_protection', 'defconfig', 'STRICT_MODULE_RWX', 'y'),
285 OptCheck('self_protection', 'defconfig', 'DEBUG_SET_MODULE_RONX', 'y'),
286 modules_not_set)] # DEBUG_SET_MODULE_RONX was before v4.11
287 l += [OR(OptCheck('self_protection', 'defconfig', 'REFCOUNT_FULL', 'y'),
288 VerCheck((5, 5)))] # REFCOUNT_FULL is enabled by default since v5.5
289 iommu_support_is_set = OptCheck('self_protection', 'defconfig', 'IOMMU_SUPPORT', 'y')
290 l += [iommu_support_is_set] # is needed for mitigating DMA attacks
291 if arch in ('X86_64', 'X86_32'):
292 l += [OptCheck('self_protection', 'defconfig', 'MICROCODE', 'y')] # is needed for mitigating CPU bugs
293 l += [OptCheck('self_protection', 'defconfig', 'RETPOLINE', 'y')]
294 l += [OptCheck('self_protection', 'defconfig', 'X86_SMAP', 'y')]
295 l += [OptCheck('self_protection', 'defconfig', 'SYN_COOKIES', 'y')] # another reason?
296 l += [OR(OptCheck('self_protection', 'defconfig', 'X86_UMIP', 'y'),
297 OptCheck('self_protection', 'defconfig', 'X86_INTEL_UMIP', 'y'))]
299 l += [OptCheck('self_protection', 'defconfig', 'PAGE_TABLE_ISOLATION', 'y')]
300 l += [OptCheck('self_protection', 'defconfig', 'RANDOMIZE_MEMORY', 'y')]
301 l += [AND(OptCheck('self_protection', 'defconfig', 'INTEL_IOMMU', 'y'),
302 iommu_support_is_set)]
303 l += [AND(OptCheck('self_protection', 'defconfig', 'AMD_IOMMU', 'y'),
304 iommu_support_is_set)]
306 l += [OptCheck('self_protection', 'defconfig', 'ARM64_PAN', 'y')]
307 l += [OptCheck('self_protection', 'defconfig', 'UNMAP_KERNEL_AT_EL0', 'y')]
308 l += [OptCheck('self_protection', 'defconfig', 'HARDEN_EL2_VECTORS', 'y')]
309 l += [OptCheck('self_protection', 'defconfig', 'RODATA_FULL_DEFAULT_ENABLED', 'y')]
310 l += [OptCheck('self_protection', 'defconfig', 'ARM64_PTR_AUTH', 'y')]
311 if arch in ('X86_64', 'ARM64'):
312 l += [OptCheck('self_protection', 'defconfig', 'VMAP_STACK', 'y')]
313 if arch in ('X86_64', 'ARM64', 'X86_32'):
314 l += [OptCheck('self_protection', 'defconfig', 'RANDOMIZE_BASE', 'y')]
315 l += [OptCheck('self_protection', 'defconfig', 'THREAD_INFO_IN_TASK', 'y')]
317 l += [OptCheck('self_protection', 'defconfig', 'CPU_SW_DOMAIN_PAN', 'y')]
318 l += [OptCheck('self_protection', 'defconfig', 'STACKPROTECTOR_PER_TASK', 'y')]
319 if arch in ('ARM64', 'ARM'):
320 l += [OptCheck('self_protection', 'defconfig', 'HARDEN_BRANCH_PREDICTOR', 'y')]
322 # 'self_protection', 'kspp'
323 l += [OptCheck('self_protection', 'kspp', 'BUG_ON_DATA_CORRUPTION', 'y')]
324 l += [OptCheck('self_protection', 'kspp', 'DEBUG_WX', 'y')]
325 l += [OptCheck('self_protection', 'kspp', 'SCHED_STACK_END_CHECK', 'y')]
326 l += [OptCheck('self_protection', 'kspp', 'SLAB_FREELIST_HARDENED', 'y')]
327 l += [OptCheck('self_protection', 'kspp', 'SLAB_FREELIST_RANDOM', 'y')]
328 l += [OptCheck('self_protection', 'kspp', 'SHUFFLE_PAGE_ALLOCATOR', 'y')]
329 l += [OptCheck('self_protection', 'kspp', 'FORTIFY_SOURCE', 'y')]
330 l += [OptCheck('self_protection', 'kspp', 'DEBUG_LIST', 'y')]
331 l += [OptCheck('self_protection', 'kspp', 'DEBUG_SG', 'y')]
332 l += [OptCheck('self_protection', 'kspp', 'DEBUG_CREDENTIALS', 'y')]
333 l += [OptCheck('self_protection', 'kspp', 'DEBUG_NOTIFIERS', 'y')]
334 l += [OptCheck('self_protection', 'kspp', 'INIT_ON_ALLOC_DEFAULT_ON', 'y')]
335 l += [OptCheck('self_protection', 'kspp', 'GCC_PLUGIN_LATENT_ENTROPY', 'y')]
336 randstruct_is_set = OptCheck('self_protection', 'kspp', 'GCC_PLUGIN_RANDSTRUCT', 'y')
337 l += [randstruct_is_set]
338 hardened_usercopy_is_set = OptCheck('self_protection', 'kspp', 'HARDENED_USERCOPY', 'y')
339 l += [hardened_usercopy_is_set]
340 l += [AND(OptCheck('self_protection', 'kspp', 'HARDENED_USERCOPY_FALLBACK', 'is not set'),
341 hardened_usercopy_is_set)]
342 l += [OR(OptCheck('self_protection', 'kspp', 'MODULE_SIG', 'y'),
344 l += [OR(OptCheck('self_protection', 'kspp', 'MODULE_SIG_ALL', 'y'),
346 l += [OR(OptCheck('self_protection', 'kspp', 'MODULE_SIG_SHA512', 'y'),
348 l += [OR(OptCheck('self_protection', 'kspp', 'MODULE_SIG_FORCE', 'y'),
349 modules_not_set)] # refers to LOCKDOWN
350 l += [OR(OptCheck('self_protection', 'kspp', 'INIT_STACK_ALL', 'y'),
351 OptCheck('self_protection', 'kspp', 'GCC_PLUGIN_STRUCTLEAK_BYREF_ALL', 'y'))]
352 l += [OR(OptCheck('self_protection', 'kspp', 'INIT_ON_FREE_DEFAULT_ON', 'y'),
353 OptCheck('self_protection', 'kspp', 'PAGE_POISONING', 'y'))] # before v5.3
354 if arch in ('X86_64', 'ARM64', 'X86_32'):
355 stackleak_is_set = OptCheck('self_protection', 'kspp', 'GCC_PLUGIN_STACKLEAK', 'y')
356 l += [stackleak_is_set]
357 if arch in ('X86_64', 'X86_32'):
358 l += [OptCheck('self_protection', 'kspp', 'DEFAULT_MMAP_MIN_ADDR', '65536')]
360 l += [OptCheck('self_protection', 'kspp', 'PAGE_TABLE_ISOLATION', 'y')]
361 l += [OptCheck('self_protection', 'kspp', 'HIGHMEM64G', 'y')]
362 l += [OptCheck('self_protection', 'kspp', 'X86_PAE', 'y')]
364 l += [OptCheck('self_protection', 'kspp', 'ARM64_SW_TTBR0_PAN', 'y')]
365 if arch in ('ARM64', 'ARM'):
366 l += [OptCheck('self_protection', 'kspp', 'SYN_COOKIES', 'y')] # another reason?
367 l += [OptCheck('self_protection', 'kspp', 'DEFAULT_MMAP_MIN_ADDR', '32768')]
369 # 'self_protection', 'clipos'
370 l += [OptCheck('self_protection', 'clipos', 'SECURITY_DMESG_RESTRICT', 'y')]
371 l += [OptCheck('self_protection', 'clipos', 'DEBUG_VIRTUAL', 'y')]
372 l += [OptCheck('self_protection', 'clipos', 'STATIC_USERMODEHELPER', 'y')] # needs userspace support
373 l += [OptCheck('self_protection', 'clipos', 'EFI_DISABLE_PCI_DMA', 'y')]
374 l += [OptCheck('self_protection', 'clipos', 'SLAB_MERGE_DEFAULT', 'is not set')] # slab_nomerge
375 l += [OptCheck('self_protection', 'clipos', 'RANDOM_TRUST_BOOTLOADER', 'is not set')]
376 l += [OptCheck('self_protection', 'clipos', 'RANDOM_TRUST_CPU', 'is not set')]
377 l += [AND(OptCheck('self_protection', 'clipos', 'GCC_PLUGIN_RANDSTRUCT_PERFORMANCE', 'is not set'),
379 if arch in ('X86_64', 'ARM64', 'X86_32'):
380 l += [AND(OptCheck('self_protection', 'clipos', 'STACKLEAK_METRICS', 'is not set'),
382 l += [AND(OptCheck('self_protection', 'clipos', 'STACKLEAK_RUNTIME_DISABLE', 'is not set'),
384 if arch in ('X86_64', 'X86_32'):
385 l += [AND(OptCheck('self_protection', 'clipos', 'INTEL_IOMMU_SVM', 'y'),
386 iommu_support_is_set)]
387 l += [AND(OptCheck('self_protection', 'clipos', 'INTEL_IOMMU_DEFAULT_ON', 'y'),
388 iommu_support_is_set)]
390 l += [AND(OptCheck('self_protection', 'clipos', 'INTEL_IOMMU', 'y'),
391 iommu_support_is_set)]
393 # 'self_protection', 'my'
394 l += [OptCheck('self_protection', 'my', 'SLUB_DEBUG_ON', 'y')] # TODO: is it better to set that via kernel cmd?
395 l += [OptCheck('self_protection', 'my', 'RESET_ATTACK_MITIGATION', 'y')] # needs userspace support (systemd)
397 l += [AND(OptCheck('self_protection', 'my', 'AMD_IOMMU_V2', 'y'),
398 iommu_support_is_set)]
401 if arch in ('X86_64', 'ARM64', 'X86_32'):
402 l += [OptCheck('security_policy', 'defconfig', 'SECURITY', 'y')] # and choose your favourite LSM
404 l += [OptCheck('security_policy', 'kspp', 'SECURITY', 'y')] # and choose your favourite LSM
405 l += [OptCheck('security_policy', 'kspp', 'SECURITY_YAMA', 'y')]
406 l += [OR(OptCheck('security_policy', 'my', 'SECURITY_WRITABLE_HOOKS', 'is not set'),
407 OptCheck('security_policy', 'kspp', 'SECURITY_SELINUX_DISABLE', 'is not set'))]
408 l += [OptCheck('security_policy', 'clipos', 'SECURITY_LOCKDOWN_LSM', 'y')]
409 l += [OptCheck('security_policy', 'clipos', 'SECURITY_LOCKDOWN_LSM_EARLY', 'y')]
410 l += [OptCheck('security_policy', 'clipos', 'LOCK_DOWN_KERNEL_FORCE_CONFIDENTIALITY', 'y')]
411 l += [OptCheck('security_policy', 'my', 'SECURITY_SAFESETID', 'y')]
412 loadpin_is_set = OptCheck('security_policy', 'my', 'SECURITY_LOADPIN', 'y')
413 l += [loadpin_is_set] # needs userspace support
414 l += [AND(OptCheck('security_policy', 'my', 'SECURITY_LOADPIN_ENFORCE', 'y'),
417 # 'cut_attack_surface', 'defconfig'
418 l += [OptCheck('cut_attack_surface', 'defconfig', 'SECCOMP', 'y')]
419 l += [OptCheck('cut_attack_surface', 'defconfig', 'SECCOMP_FILTER', 'y')]
420 if arch in ('X86_64', 'ARM64', 'X86_32'):
421 l += [OR(OptCheck('cut_attack_surface', 'defconfig', 'STRICT_DEVMEM', 'y'),
422 devmem_not_set)] # refers to LOCKDOWN
424 # 'cut_attack_surface', 'kspp'
425 l += [OptCheck('cut_attack_surface', 'kspp', 'ACPI_CUSTOM_METHOD', 'is not set')] # refers to LOCKDOWN
426 l += [OptCheck('cut_attack_surface', 'kspp', 'COMPAT_BRK', 'is not set')]
427 l += [OptCheck('cut_attack_surface', 'kspp', 'DEVKMEM', 'is not set')] # refers to LOCKDOWN
428 l += [OptCheck('cut_attack_surface', 'kspp', 'COMPAT_VDSO', 'is not set')]
429 l += [OptCheck('cut_attack_surface', 'kspp', 'BINFMT_MISC', 'is not set')]
430 l += [OptCheck('cut_attack_surface', 'kspp', 'INET_DIAG', 'is not set')]
431 l += [OptCheck('cut_attack_surface', 'kspp', 'KEXEC', 'is not set')] # refers to LOCKDOWN
432 l += [OptCheck('cut_attack_surface', 'kspp', 'PROC_KCORE', 'is not set')] # refers to LOCKDOWN
433 l += [OptCheck('cut_attack_surface', 'kspp', 'LEGACY_PTYS', 'is not set')]
434 l += [OptCheck('cut_attack_surface', 'kspp', 'HIBERNATION', 'is not set')] # refers to LOCKDOWN
435 l += [OptCheck('cut_attack_surface', 'kspp', 'IA32_EMULATION', 'is not set')]
436 l += [OptCheck('cut_attack_surface', 'kspp', 'X86_X32', 'is not set')]
437 l += [OptCheck('cut_attack_surface', 'kspp', 'MODIFY_LDT_SYSCALL', 'is not set')]
438 l += [OptCheck('cut_attack_surface', 'kspp', 'OABI_COMPAT', 'is not set')]
439 l += [modules_not_set]
440 l += [devmem_not_set]
441 l += [OR(OptCheck('cut_attack_surface', 'kspp', 'IO_STRICT_DEVMEM', 'y'),
442 devmem_not_set)] # refers to LOCKDOWN
444 l += [OR(OptCheck('cut_attack_surface', 'kspp', 'STRICT_DEVMEM', 'y'),
445 devmem_not_set)] # refers to LOCKDOWN
447 l += [OptCheck('cut_attack_surface', 'kspp', 'LEGACY_VSYSCALL_NONE', 'y')] # 'vsyscall=none'
449 # 'cut_attack_surface', 'grsecurity'
450 l += [OptCheck('cut_attack_surface', 'grsecurity', 'ZSMALLOC_STAT', 'is not set')]
451 l += [OptCheck('cut_attack_surface', 'grsecurity', 'PAGE_OWNER', 'is not set')]
452 l += [OptCheck('cut_attack_surface', 'grsecurity', 'DEBUG_KMEMLEAK', 'is not set')]
453 l += [OptCheck('cut_attack_surface', 'grsecurity', 'BINFMT_AOUT', 'is not set')]
454 l += [OptCheck('cut_attack_surface', 'grsecurity', 'KPROBES', 'is not set')] # refers to LOCKDOWN
455 l += [OptCheck('cut_attack_surface', 'grsecurity', 'UPROBES', 'is not set')]
456 l += [OptCheck('cut_attack_surface', 'grsecurity', 'GENERIC_TRACER', 'is not set')] # refers to LOCKDOWN
457 l += [OptCheck('cut_attack_surface', 'grsecurity', 'PROC_VMCORE', 'is not set')]
458 l += [OptCheck('cut_attack_surface', 'grsecurity', 'PROC_PAGE_MONITOR', 'is not set')]
459 l += [OptCheck('cut_attack_surface', 'grsecurity', 'USELIB', 'is not set')]
460 l += [OptCheck('cut_attack_surface', 'grsecurity', 'CHECKPOINT_RESTORE', 'is not set')]
461 l += [OptCheck('cut_attack_surface', 'grsecurity', 'USERFAULTFD', 'is not set')]
462 l += [OptCheck('cut_attack_surface', 'grsecurity', 'HWPOISON_INJECT', 'is not set')]
463 l += [OptCheck('cut_attack_surface', 'grsecurity', 'MEM_SOFT_DIRTY', 'is not set')]
464 l += [OptCheck('cut_attack_surface', 'grsecurity', 'DEVPORT', 'is not set')] # refers to LOCKDOWN
465 l += [OptCheck('cut_attack_surface', 'grsecurity', 'DEBUG_FS', 'is not set')] # refers to LOCKDOWN
466 l += [OptCheck('cut_attack_surface', 'grsecurity', 'NOTIFIER_ERROR_INJECTION', 'is not set')]
467 l += [AND(OptCheck('cut_attack_surface', 'grsecurity', 'X86_PTDUMP', 'is not set'),
468 OptCheck('cut_attack_surface', 'my', 'PTDUMP_DEBUGFS', 'is not set'))]
470 # 'cut_attack_surface', 'maintainer'
471 l += [OptCheck('cut_attack_surface', 'maintainer', 'DRM_LEGACY', 'is not set')]
472 l += [OptCheck('cut_attack_surface', 'maintainer', 'FB', 'is not set')]
473 l += [OptCheck('cut_attack_surface', 'maintainer', 'VT', 'is not set')]
475 # 'cut_attack_surface', 'grapheneos'
476 l += [OptCheck('cut_attack_surface', 'grapheneos', 'AIO', 'is not set')]
478 # 'cut_attack_surface', 'clipos'
479 l += [OptCheck('cut_attack_surface', 'clipos', 'STAGING', 'is not set')]
480 l += [OptCheck('cut_attack_surface', 'clipos', 'KSM', 'is not set')] # to prevent FLUSH+RELOAD attack
481 # l += [OptCheck('cut_attack_surface', 'clipos', 'IKCONFIG', 'is not set')] # no, IKCONFIG is needed for this check :)
482 l += [OptCheck('cut_attack_surface', 'clipos', 'KALLSYMS', 'is not set')]
483 l += [OptCheck('cut_attack_surface', 'clipos', 'X86_VSYSCALL_EMULATION', 'is not set')]
484 l += [OptCheck('cut_attack_surface', 'clipos', 'MAGIC_SYSRQ', 'is not set')]
485 l += [OptCheck('cut_attack_surface', 'clipos', 'KEXEC_FILE', 'is not set')] # refers to LOCKDOWN (permissive)
486 l += [OptCheck('cut_attack_surface', 'clipos', 'USER_NS', 'is not set')] # user.max_user_namespaces=0
487 l += [OptCheck('cut_attack_surface', 'clipos', 'X86_MSR', 'is not set')] # refers to LOCKDOWN
488 l += [OptCheck('cut_attack_surface', 'clipos', 'X86_CPUID', 'is not set')]
489 l += [OptCheck('cut_attack_surface', 'clipos', 'IO_URING', 'is not set')]
490 l += [OptCheck('cut_attack_surface', 'clipos', 'X86_IOPL_IOPERM', 'is not set')] # refers to LOCKDOWN
491 l += [OptCheck('cut_attack_surface', 'clipos', 'ACPI_TABLE_UPGRADE', 'is not set')] # refers to LOCKDOWN
492 l += [OptCheck('cut_attack_surface', 'clipos', 'EFI_CUSTOM_SSDT_OVERLAYS', 'is not set')]
493 l += [AND(OptCheck('cut_attack_surface', 'clipos', 'LDISC_AUTOLOAD', 'is not set'),
494 PresenceCheck('LDISC_AUTOLOAD'))]
495 if arch in ('X86_64', 'X86_32'):
496 l += [OptCheck('cut_attack_surface', 'clipos', 'X86_INTEL_TSX_MODE_OFF', 'y')] # tsx=off
498 # 'cut_attack_surface', 'lockdown'
499 l += [OptCheck('cut_attack_surface', 'lockdown', 'EFI_TEST', 'is not set')] # refers to LOCKDOWN
500 l += [OptCheck('cut_attack_surface', 'lockdown', 'BPF_SYSCALL', 'is not set')] # refers to LOCKDOWN
501 l += [OptCheck('cut_attack_surface', 'lockdown', 'MMIOTRACE_TEST', 'is not set')] # refers to LOCKDOWN
503 # 'cut_attack_surface', 'my'
504 l += [OptCheck('cut_attack_surface', 'my', 'MMIOTRACE', 'is not set')] # refers to LOCKDOWN (permissive)
505 l += [OptCheck('cut_attack_surface', 'my', 'LIVEPATCH', 'is not set')]
506 l += [OptCheck('cut_attack_surface', 'my', 'IP_DCCP', 'is not set')]
507 l += [OptCheck('cut_attack_surface', 'my', 'IP_SCTP', 'is not set')]
508 l += [OptCheck('cut_attack_surface', 'my', 'FTRACE', 'is not set')] # refers to LOCKDOWN
509 l += [OptCheck('cut_attack_surface', 'my', 'VIDEO_VIVID', 'is not set')]
510 l += [OptCheck('cut_attack_surface', 'my', 'INPUT_EVBUG', 'is not set')] # Can be used as a keylogger
512 # 'userspace_hardening'
513 if arch in ('X86_64', 'ARM64', 'X86_32'):
514 l += [OptCheck('userspace_hardening', 'defconfig', 'INTEGRITY', 'y')]
516 l += [OptCheck('userspace_hardening', 'my', 'INTEGRITY', 'y')]
517 if arch in ('ARM', 'X86_32'):
518 l += [OptCheck('userspace_hardening', 'defconfig', 'VMSPLIT_3G', 'y')]
519 if arch in ('X86_64', 'ARM64'):
520 l += [OptCheck('userspace_hardening', 'clipos', 'ARCH_MMAP_RND_BITS', '32')]
521 if arch in ('X86_32', 'ARM'):
522 l += [OptCheck('userspace_hardening', 'my', 'ARCH_MMAP_RND_BITS', '16')]
524 # l += [OptCheck('feature_test', 'my', 'LKDTM', 'm')] # only for debugging!
527 def print_unknown_options(checklist, parsed_options):
529 for opt in checklist:
530 if hasattr(opt, 'opts'):
532 if hasattr(o, 'name'):
533 known_options.append(o.name)
535 known_options.append(opt.name)
536 for option, value in parsed_options.items():
537 if option not in known_options:
538 print('[?] No rule for option {} ({})'.format(option, value))
541 def print_checklist(mode, checklist, with_results):
545 opt = ['CONFIG_'+o.name, o.expected, o.decision, o.reason]
549 print(json.dumps(opts))
556 print('=' * sep_line_len)
557 print('{:^45}|{:^13}|{:^10}|{:^20}'.format('option name', 'desired val', 'decision', 'reason'), end='')
559 print('| {}'.format('check result'), end='')
561 print('=' * sep_line_len)
564 for opt in checklist:
566 if mode == 'show_ok':
567 if not opt.result.startswith('OK'):
569 if mode == 'show_fail':
570 if not opt.result.startswith('FAIL'):
572 opt.table_print(mode, with_results)
574 if mode == 'verbose':
575 print('-' * sep_line_len)
580 fail_count = len(list(filter(lambda opt: opt.result.startswith('FAIL'), checklist)))
582 ok_count = len(list(filter(lambda opt: opt.result.startswith('OK'), checklist)))
584 if mode == 'show_ok':
585 fail_suppressed = ' (suppressed in output)'
586 if mode == 'show_fail':
587 ok_suppressed = ' (suppressed in output)'
589 print('[+] Config check is finished: \'OK\' - {}{} / \'FAIL\' - {}{}'.format(ok_count, ok_suppressed, fail_count, fail_suppressed))
592 def perform_check(opt, parsed_options, kernel_version):
593 if hasattr(opt, 'opts'):
594 # prepare ComplexOptCheck
596 if hasattr(o, 'opts'):
597 # Recursion for nested ComplexOptChecks
598 perform_check(o, parsed_options, kernel_version)
599 if hasattr(o, 'state'):
600 o.state = parsed_options.get(o.name, None)
601 if hasattr(o, 'ver'):
602 o.ver = kernel_version
604 # prepare simple check, opt.state is mandatory
605 if not hasattr(opt, 'state'):
606 sys.exit('[!] ERROR: bad simple check {}'.format(vars(opt)))
607 opt.state = parsed_options.get(opt.name, None)
611 def perform_checks(checklist, parsed_options, kernel_version):
612 for opt in checklist:
613 perform_check(opt, parsed_options, kernel_version)
616 def parse_config_file(parsed_options, fname):
617 with open(fname, 'r') as f:
618 opt_is_on = re.compile("CONFIG_[a-zA-Z0-9_]*=[a-zA-Z0-9_\"]*")
619 opt_is_off = re.compile("# CONFIG_[a-zA-Z0-9_]* is not set")
621 for line in f.readlines():
626 if opt_is_on.match(line):
627 option, value = line[7:].split('=', 1)
628 elif opt_is_off.match(line):
629 option, value = line[9:].split(' ', 1)
630 if value != 'is not set':
631 sys.exit('[!] ERROR: bad disabled config option "{}"'.format(line))
633 if option in parsed_options:
634 sys.exit('[!] ERROR: config option "{}" exists multiple times'.format(line))
637 parsed_options[option] = value
639 return parsed_options
645 # - reporting about unknown kernel options in the config
646 # - verbose printing of ComplexOptCheck items
647 # * json mode for printing the results in JSON format
648 report_modes = ['verbose', 'json', 'show_ok', 'show_fail']
649 supported_archs = ['X86_64', 'X86_32', 'ARM64', 'ARM']
650 parser = ArgumentParser(prog='kconfig-hardened-check',
651 description='Checks the hardening options in the Linux kernel config')
652 parser.add_argument('--version', action='version', version='%(prog)s ' + __version__)
653 parser.add_argument('-p', '--print', choices=supported_archs,
654 help='print hardening preferences for selected architecture')
655 parser.add_argument('-c', '--config',
656 help='check the kernel config file against these preferences')
657 parser.add_argument('-m', '--mode', choices=report_modes,
658 help='choose the report mode')
659 args = parser.parse_args()
665 print("[+] Special report mode: {}".format(mode))
667 config_checklist = []
671 print('[+] Config file to check: {}'.format(args.config))
673 arch, msg = detect_arch(args.config, supported_archs)
675 sys.exit('[!] ERROR: {}'.format(msg))
677 print('[+] Detected architecture: {}'.format(arch))
679 kernel_version, msg = detect_version(args.config)
680 if not kernel_version:
681 sys.exit('[!] ERROR: {}'.format(msg))
683 print('[+] Detected kernel version: {}.{}'.format(kernel_version[0], kernel_version[1]))
685 construct_checklist(config_checklist, arch)
686 parsed_options = OrderedDict()
687 parse_config_file(parsed_options, args.config)
688 perform_checks(config_checklist, parsed_options, kernel_version)
690 if mode == 'verbose':
691 print_unknown_options(config_checklist, parsed_options)
692 print_checklist(mode, config_checklist, True)
697 if mode in ('show_ok', 'show_fail'):
698 sys.exit('[!] ERROR: please use "{}" mode for checking the kernel config'.format(mode))
700 construct_checklist(config_checklist, arch)
702 print('[+] Printing kernel hardening preferences for {}...'.format(arch))
703 print_checklist(mode, config_checklist, False)
709 if __name__ == '__main__':