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 # kernel.unprivileged_bpf_disabled=1
45 # net.core.bpf_jit_harden=2
47 # vm.unprivileged_userfaultfd=0
49 # dev.tty.ldisc_autoload=0
50 # fs.protected_symlinks=1
51 # fs.protected_hardlinks=1
52 # fs.protected_fifos=2
53 # fs.protected_regular=2
55 # kernel.modules_disabled=1
58 from argparse import ArgumentParser
59 from collections import OrderedDict
62 from .__about__ import __version__
64 # pylint: disable=line-too-long,bad-whitespace,too-many-branches
65 # pylint: disable=too-many-statements,global-statement
69 def __init__(self, reason, decision, name, expected):
71 self.expected = expected
72 self.decision = decision
78 if self.expected == self.state:
80 elif self.state is None:
81 if self.expected == 'is not set':
82 self.result = 'OK: not found'
84 self.result = 'FAIL: not found'
86 self.result = 'FAIL: "' + self.state + '"'
88 if self.result.startswith('OK'):
92 def table_print(self, mode, with_results):
93 print('CONFIG_{:<38}|{:^13}|{:^10}|{:^20}'.format(self.name, self.expected, self.decision, self.reason), end='')
95 print('| {}'.format(self.result), end='')
99 def __init__(self, ver_expected):
100 self.ver_expected = ver_expected
105 if self.ver[0] > self.ver_expected[0]:
106 self.result = 'OK: version >= ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
108 if self.ver[0] < self.ver_expected[0]:
109 self.result = 'FAIL: version < ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
111 if self.ver[1] >= self.ver_expected[1]:
112 self.result = 'OK: version >= ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
114 self.result = 'FAIL: version < ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
117 def table_print(self, mode, with_results):
118 ver_req = 'kernel version >= ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
119 print('{:<91}'.format(ver_req), end='')
121 print('| {}'.format(self.result), end='')
125 def __init__(self, name):
131 if self.state is None:
132 self.result = 'FAIL: not present'
134 self.result = 'OK: is present'
137 def table_print(self, mode, with_results):
138 print('CONFIG_{:<84}'.format(self.name + ' is present'), end='')
140 print('| {}'.format(self.result), end='')
143 class ComplexOptCheck:
144 def __init__(self, *opts):
150 return self.opts[0].name
154 return self.opts[0].expected
158 return self.opts[0].decision
162 return self.opts[0].reason
164 def table_print(self, mode, with_results):
165 if mode == 'verbose':
166 print(' {:87}'.format('<<< ' + self.__class__.__name__ + ' >>>'), end='')
168 print('| {}'.format(self.result), end='')
171 o.table_print(mode, with_results)
174 o.table_print(mode, False)
176 print('| {}'.format(self.result), end='')
179 class OR(ComplexOptCheck):
180 # self.opts[0] is the option that this OR-check is about.
182 # OR(<X_is_hardened>, <X_is_disabled>)
183 # OR(<X_is_hardened>, <old_X_is_hardened>)
187 sys.exit('[!] ERROR: invalid OR check')
189 for i, opt in enumerate(self.opts):
192 if i == 0 or not hasattr(opt, 'expected'):
193 self.result = opt.result
195 self.result = 'OK: CONFIG_{} "{}"'.format(opt.name, opt.expected)
197 self.result = self.opts[0].result
201 class AND(ComplexOptCheck):
202 # self.opts[0] is the option that this AND-check is about.
204 # AND(<suboption>, <main_option>)
205 # Suboption is not checked if checking of the main_option is failed.
206 # AND(<X_is_disabled>, <old_X_is_disabled>)
209 for i, opt in reversed(list(enumerate(self.opts))):
212 self.result = opt.result
215 if hasattr(opt, 'expected'):
216 self.result = 'FAIL: CONFIG_{} not "{}"'.format(opt.name, opt.expected)
218 self.result = opt.result
221 sys.exit('[!] ERROR: invalid AND check')
224 def detect_arch(fname, archs):
225 with open(fname, 'r') as f:
226 arch_pattern = re.compile("CONFIG_[a-zA-Z0-9_]*=y")
228 for line in f.readlines():
229 if arch_pattern.match(line):
230 option, _ = line[7:].split('=', 1)
235 return None, 'more than one supported architecture is detected'
237 return None, 'failed to detect architecture'
241 def detect_version(fname):
242 with open(fname, 'r') as f:
243 ver_pattern = re.compile("# Linux/.* Kernel Configuration")
244 for line in f.readlines():
245 if ver_pattern.match(line):
249 ver_numbers = ver_str.split('.')
250 if len(ver_numbers) < 3 or not ver_numbers[0].isdigit() or not ver_numbers[1].isdigit():
251 msg = 'failed to parse the version "' + ver_str + '"'
253 return (int(ver_numbers[0]), int(ver_numbers[1])), None
254 return None, 'no kernel version detected'
257 def construct_checklist(l, arch):
258 modules_not_set = OptCheck('cut_attack_surface', 'kspp', 'MODULES', 'is not set')
259 devmem_not_set = OptCheck('cut_attack_surface', 'kspp', 'DEVMEM', 'is not set') # refers to LOCKDOWN
261 # 'self_protection', 'defconfig'
262 l += [OptCheck('self_protection', 'defconfig', 'BUG', 'y')]
263 l += [OptCheck('self_protection', 'defconfig', 'SLUB_DEBUG', 'y')]
264 l += [OptCheck('self_protection', 'defconfig', 'GCC_PLUGINS', 'y')]
265 l += [OR(OptCheck('self_protection', 'defconfig', 'STACKPROTECTOR_STRONG', 'y'),
266 OptCheck('self_protection', 'defconfig', 'CC_STACKPROTECTOR_STRONG', 'y'))]
267 l += [OR(OptCheck('self_protection', 'defconfig', 'STRICT_KERNEL_RWX', 'y'),
268 OptCheck('self_protection', 'defconfig', 'DEBUG_RODATA', 'y'))] # before v4.11
269 l += [OR(OptCheck('self_protection', 'defconfig', 'STRICT_MODULE_RWX', 'y'),
270 OptCheck('self_protection', 'defconfig', 'DEBUG_SET_MODULE_RONX', 'y'),
271 modules_not_set)] # DEBUG_SET_MODULE_RONX was before v4.11
272 l += [OR(OptCheck('self_protection', 'defconfig', 'REFCOUNT_FULL', 'y'),
273 VerCheck((5, 5)))] # REFCOUNT_FULL is enabled by default since v5.5
274 iommu_support_is_set = OptCheck('self_protection', 'defconfig', 'IOMMU_SUPPORT', 'y')
275 l += [iommu_support_is_set] # is needed for mitigating DMA attacks
276 if arch in ('X86_64', 'X86_32'):
277 l += [OptCheck('self_protection', 'defconfig', 'MICROCODE', 'y')] # is needed for mitigating CPU bugs
278 l += [OptCheck('self_protection', 'defconfig', 'RETPOLINE', 'y')]
279 l += [OptCheck('self_protection', 'defconfig', 'X86_SMAP', 'y')]
280 l += [OptCheck('self_protection', 'defconfig', 'SYN_COOKIES', 'y')] # another reason?
281 l += [OR(OptCheck('self_protection', 'defconfig', 'X86_UMIP', 'y'),
282 OptCheck('self_protection', 'defconfig', 'X86_INTEL_UMIP', 'y'))]
284 l += [OptCheck('self_protection', 'defconfig', 'PAGE_TABLE_ISOLATION', 'y')]
285 l += [OptCheck('self_protection', 'defconfig', 'RANDOMIZE_MEMORY', 'y')]
286 l += [AND(OptCheck('self_protection', 'defconfig', 'INTEL_IOMMU', 'y'),
287 iommu_support_is_set)]
288 l += [AND(OptCheck('self_protection', 'defconfig', 'AMD_IOMMU', 'y'),
289 iommu_support_is_set)]
291 l += [OptCheck('self_protection', 'defconfig', 'ARM64_PAN', 'y')]
292 l += [OptCheck('self_protection', 'defconfig', 'UNMAP_KERNEL_AT_EL0', 'y')]
293 l += [OptCheck('self_protection', 'defconfig', 'HARDEN_EL2_VECTORS', 'y')]
294 l += [OptCheck('self_protection', 'defconfig', 'RODATA_FULL_DEFAULT_ENABLED', 'y')]
295 l += [OptCheck('self_protection', 'defconfig', 'ARM64_PTR_AUTH', 'y')]
296 if arch in ('X86_64', 'ARM64'):
297 l += [OptCheck('self_protection', 'defconfig', 'VMAP_STACK', 'y')]
298 if arch in ('X86_64', 'ARM64', 'X86_32'):
299 l += [OptCheck('self_protection', 'defconfig', 'RANDOMIZE_BASE', 'y')]
300 l += [OptCheck('self_protection', 'defconfig', 'THREAD_INFO_IN_TASK', 'y')]
302 l += [OptCheck('self_protection', 'defconfig', 'CPU_SW_DOMAIN_PAN', 'y')]
303 l += [OptCheck('self_protection', 'defconfig', 'STACKPROTECTOR_PER_TASK', 'y')]
304 if arch in ('ARM64', 'ARM'):
305 l += [OptCheck('self_protection', 'defconfig', 'HARDEN_BRANCH_PREDICTOR', 'y')]
307 # 'self_protection', 'kspp'
308 l += [OptCheck('self_protection', 'kspp', 'BUG_ON_DATA_CORRUPTION', 'y')]
309 l += [OptCheck('self_protection', 'kspp', 'DEBUG_WX', 'y')]
310 l += [OptCheck('self_protection', 'kspp', 'SCHED_STACK_END_CHECK', 'y')]
311 l += [OptCheck('self_protection', 'kspp', 'SLAB_FREELIST_HARDENED', 'y')]
312 l += [OptCheck('self_protection', 'kspp', 'SLAB_FREELIST_RANDOM', 'y')]
313 l += [OptCheck('self_protection', 'kspp', 'SHUFFLE_PAGE_ALLOCATOR', 'y')]
314 l += [OptCheck('self_protection', 'kspp', 'FORTIFY_SOURCE', 'y')]
315 l += [OptCheck('self_protection', 'kspp', 'DEBUG_LIST', 'y')]
316 l += [OptCheck('self_protection', 'kspp', 'DEBUG_SG', 'y')]
317 l += [OptCheck('self_protection', 'kspp', 'DEBUG_CREDENTIALS', 'y')]
318 l += [OptCheck('self_protection', 'kspp', 'DEBUG_NOTIFIERS', 'y')]
319 l += [OptCheck('self_protection', 'kspp', 'INIT_ON_ALLOC_DEFAULT_ON', 'y')]
320 l += [OptCheck('self_protection', 'kspp', 'GCC_PLUGIN_LATENT_ENTROPY', 'y')]
321 randstruct_is_set = OptCheck('self_protection', 'kspp', 'GCC_PLUGIN_RANDSTRUCT', 'y')
322 l += [randstruct_is_set]
323 hardened_usercopy_is_set = OptCheck('self_protection', 'kspp', 'HARDENED_USERCOPY', 'y')
324 l += [hardened_usercopy_is_set]
325 l += [AND(OptCheck('self_protection', 'kspp', 'HARDENED_USERCOPY_FALLBACK', 'is not set'),
326 hardened_usercopy_is_set)]
327 l += [OR(OptCheck('self_protection', 'kspp', 'MODULE_SIG', 'y'),
329 l += [OR(OptCheck('self_protection', 'kspp', 'MODULE_SIG_ALL', 'y'),
331 l += [OR(OptCheck('self_protection', 'kspp', 'MODULE_SIG_SHA512', 'y'),
333 l += [OR(OptCheck('self_protection', 'kspp', 'MODULE_SIG_FORCE', 'y'),
334 modules_not_set)] # refers to LOCKDOWN
335 l += [OR(OptCheck('self_protection', 'kspp', 'INIT_STACK_ALL', 'y'),
336 OptCheck('self_protection', 'kspp', 'GCC_PLUGIN_STRUCTLEAK_BYREF_ALL', 'y'))]
337 l += [OR(OptCheck('self_protection', 'kspp', 'INIT_ON_FREE_DEFAULT_ON', 'y'),
338 OptCheck('self_protection', 'kspp', 'PAGE_POISONING', 'y'))] # before v5.3
339 if arch in ('X86_64', 'ARM64', 'X86_32'):
340 stackleak_is_set = OptCheck('self_protection', 'kspp', 'GCC_PLUGIN_STACKLEAK', 'y')
341 l += [stackleak_is_set]
342 if arch in ('X86_64', 'X86_32'):
343 l += [OptCheck('self_protection', 'kspp', 'DEFAULT_MMAP_MIN_ADDR', '65536')]
345 l += [OptCheck('self_protection', 'kspp', 'PAGE_TABLE_ISOLATION', 'y')]
346 l += [OptCheck('self_protection', 'kspp', 'HIGHMEM64G', 'y')]
347 l += [OptCheck('self_protection', 'kspp', 'X86_PAE', 'y')]
349 l += [OptCheck('self_protection', 'kspp', 'ARM64_SW_TTBR0_PAN', 'y')]
350 if arch in ('ARM64', 'ARM'):
351 l += [OptCheck('self_protection', 'kspp', 'SYN_COOKIES', 'y')] # another reason?
352 l += [OptCheck('self_protection', 'kspp', 'DEFAULT_MMAP_MIN_ADDR', '32768')]
354 # 'self_protection', 'clipos'
355 l += [OptCheck('self_protection', 'clipos', 'SECURITY_DMESG_RESTRICT', 'y')]
356 l += [OptCheck('self_protection', 'clipos', 'DEBUG_VIRTUAL', 'y')]
357 l += [OptCheck('self_protection', 'clipos', 'STATIC_USERMODEHELPER', 'y')] # needs userspace support
358 l += [OptCheck('self_protection', 'clipos', 'SLAB_MERGE_DEFAULT', 'is not set')] # slab_nomerge
359 l += [OptCheck('self_protection', 'clipos', 'RANDOM_TRUST_BOOTLOADER', 'is not set')]
360 l += [OptCheck('self_protection', 'clipos', 'RANDOM_TRUST_CPU', 'is not set')]
361 l += [AND(OptCheck('self_protection', 'clipos', 'GCC_PLUGIN_RANDSTRUCT_PERFORMANCE', 'is not set'),
363 if arch in ('X86_64', 'ARM64', 'X86_32'):
364 l += [AND(OptCheck('self_protection', 'clipos', 'STACKLEAK_METRICS', 'is not set'),
366 l += [AND(OptCheck('self_protection', 'clipos', 'STACKLEAK_RUNTIME_DISABLE', 'is not set'),
368 if arch in ('X86_64', 'X86_32'):
369 l += [AND(OptCheck('self_protection', 'clipos', 'INTEL_IOMMU_SVM', 'y'),
370 iommu_support_is_set)]
371 l += [AND(OptCheck('self_protection', 'clipos', 'INTEL_IOMMU_DEFAULT_ON', 'y'),
372 iommu_support_is_set)]
374 l += [AND(OptCheck('self_protection', 'clipos', 'INTEL_IOMMU', 'y'),
375 iommu_support_is_set)]
377 # 'self_protection', 'my'
378 l += [OptCheck('self_protection', 'my', 'SLUB_DEBUG_ON', 'y')]
379 l += [OptCheck('self_protection', 'my', 'RESET_ATTACK_MITIGATION', 'y')] # needs userspace support (systemd)
381 l += [AND(OptCheck('self_protection', 'my', 'AMD_IOMMU_V2', 'y'),
382 iommu_support_is_set)]
385 if arch in ('X86_64', 'ARM64', 'X86_32'):
386 l += [OptCheck('security_policy', 'defconfig', 'SECURITY', 'y')] # and choose your favourite LSM
388 l += [OptCheck('security_policy', 'kspp', 'SECURITY', 'y')] # and choose your favourite LSM
389 l += [OptCheck('security_policy', 'kspp', 'SECURITY_YAMA', 'y')]
390 l += [OR(OptCheck('security_policy', 'my', 'SECURITY_WRITABLE_HOOKS', 'is not set'),
391 OptCheck('security_policy', 'kspp', 'SECURITY_SELINUX_DISABLE', 'is not set'))]
392 l += [OptCheck('security_policy', 'clipos', 'SECURITY_LOCKDOWN_LSM', 'y')]
393 l += [OptCheck('security_policy', 'clipos', 'SECURITY_LOCKDOWN_LSM_EARLY', 'y')]
394 l += [OptCheck('security_policy', 'clipos', 'LOCK_DOWN_KERNEL_FORCE_CONFIDENTIALITY', 'y')]
395 l += [OptCheck('security_policy', 'my', 'SECURITY_SAFESETID', 'y')]
396 loadpin_is_set = OptCheck('security_policy', 'my', 'SECURITY_LOADPIN', 'y')
397 l += [loadpin_is_set] # needs userspace support
398 l += [AND(OptCheck('security_policy', 'my', 'SECURITY_LOADPIN_ENFORCE', 'y'),
401 # 'cut_attack_surface', 'defconfig'
402 l += [OptCheck('cut_attack_surface', 'defconfig', 'SECCOMP', 'y')]
403 l += [OptCheck('cut_attack_surface', 'defconfig', 'SECCOMP_FILTER', 'y')]
404 if arch in ('X86_64', 'ARM64', 'X86_32'):
405 l += [OR(OptCheck('cut_attack_surface', 'defconfig', 'STRICT_DEVMEM', 'y'),
406 devmem_not_set)] # refers to LOCKDOWN
408 # 'cut_attack_surface', 'kspp'
409 l += [OptCheck('cut_attack_surface', 'kspp', 'ACPI_CUSTOM_METHOD', 'is not set')] # refers to LOCKDOWN
410 l += [OptCheck('cut_attack_surface', 'kspp', 'COMPAT_BRK', 'is not set')]
411 l += [OptCheck('cut_attack_surface', 'kspp', 'DEVKMEM', 'is not set')] # refers to LOCKDOWN
412 l += [OptCheck('cut_attack_surface', 'kspp', 'COMPAT_VDSO', 'is not set')]
413 l += [OptCheck('cut_attack_surface', 'kspp', 'BINFMT_MISC', 'is not set')]
414 l += [OptCheck('cut_attack_surface', 'kspp', 'INET_DIAG', 'is not set')]
415 l += [OptCheck('cut_attack_surface', 'kspp', 'KEXEC', 'is not set')] # refers to LOCKDOWN
416 l += [OptCheck('cut_attack_surface', 'kspp', 'PROC_KCORE', 'is not set')] # refers to LOCKDOWN
417 l += [OptCheck('cut_attack_surface', 'kspp', 'LEGACY_PTYS', 'is not set')]
418 l += [OptCheck('cut_attack_surface', 'kspp', 'HIBERNATION', 'is not set')] # refers to LOCKDOWN
419 l += [OptCheck('cut_attack_surface', 'kspp', 'IA32_EMULATION', 'is not set')]
420 l += [OptCheck('cut_attack_surface', 'kspp', 'X86_X32', 'is not set')]
421 l += [OptCheck('cut_attack_surface', 'kspp', 'MODIFY_LDT_SYSCALL', 'is not set')]
422 l += [OptCheck('cut_attack_surface', 'kspp', 'OABI_COMPAT', 'is not set')]
423 l += [modules_not_set]
424 l += [devmem_not_set]
425 l += [OR(OptCheck('cut_attack_surface', 'kspp', 'IO_STRICT_DEVMEM', 'y'),
426 devmem_not_set)] # refers to LOCKDOWN
428 l += [OR(OptCheck('cut_attack_surface', 'kspp', 'STRICT_DEVMEM', 'y'),
429 devmem_not_set)] # refers to LOCKDOWN
431 l += [OptCheck('cut_attack_surface', 'kspp', 'LEGACY_VSYSCALL_NONE', 'y')] # 'vsyscall=none'
433 # 'cut_attack_surface', 'grsecurity'
434 l += [OptCheck('cut_attack_surface', 'grsecurity', 'ZSMALLOC_STAT', 'is not set')]
435 l += [OptCheck('cut_attack_surface', 'grsecurity', 'PAGE_OWNER', 'is not set')]
436 l += [OptCheck('cut_attack_surface', 'grsecurity', 'DEBUG_KMEMLEAK', 'is not set')]
437 l += [OptCheck('cut_attack_surface', 'grsecurity', 'BINFMT_AOUT', 'is not set')]
438 l += [OptCheck('cut_attack_surface', 'grsecurity', 'KPROBES', 'is not set')] # refers to LOCKDOWN
439 l += [OptCheck('cut_attack_surface', 'grsecurity', 'UPROBES', 'is not set')]
440 l += [OptCheck('cut_attack_surface', 'grsecurity', 'GENERIC_TRACER', 'is not set')] # refers to LOCKDOWN
441 l += [OptCheck('cut_attack_surface', 'grsecurity', 'PROC_VMCORE', 'is not set')]
442 l += [OptCheck('cut_attack_surface', 'grsecurity', 'PROC_PAGE_MONITOR', 'is not set')]
443 l += [OptCheck('cut_attack_surface', 'grsecurity', 'USELIB', 'is not set')]
444 l += [OptCheck('cut_attack_surface', 'grsecurity', 'CHECKPOINT_RESTORE', 'is not set')]
445 l += [OptCheck('cut_attack_surface', 'grsecurity', 'USERFAULTFD', 'is not set')]
446 l += [OptCheck('cut_attack_surface', 'grsecurity', 'HWPOISON_INJECT', 'is not set')]
447 l += [OptCheck('cut_attack_surface', 'grsecurity', 'MEM_SOFT_DIRTY', 'is not set')]
448 l += [OptCheck('cut_attack_surface', 'grsecurity', 'DEVPORT', 'is not set')] # refers to LOCKDOWN
449 l += [OptCheck('cut_attack_surface', 'grsecurity', 'DEBUG_FS', 'is not set')] # refers to LOCKDOWN
450 l += [OptCheck('cut_attack_surface', 'grsecurity', 'NOTIFIER_ERROR_INJECTION','is not set')]
451 l += [AND(OptCheck('cut_attack_surface', 'grsecurity', 'X86_PTDUMP', 'is not set'),
452 OptCheck('cut_attack_surface', 'my', 'PTDUMP_DEBUGFS', 'is not set'))]
454 # 'cut_attack_surface', 'maintainer'
455 l += [OptCheck('cut_attack_surface', 'maintainer', 'DRM_LEGACY', 'is not set')]
456 l += [OptCheck('cut_attack_surface', 'maintainer', 'FB', 'is not set')]
457 l += [OptCheck('cut_attack_surface', 'maintainer', 'VT', 'is not set')]
459 # 'cut_attack_surface', 'lockdown'
460 l += [OptCheck('cut_attack_surface', 'lockdown', 'ACPI_TABLE_UPGRADE', 'is not set')] # refers to LOCKDOWN
461 l += [OptCheck('cut_attack_surface', 'lockdown', 'X86_IOPL_IOPERM', 'is not set')] # refers to LOCKDOWN
462 l += [OptCheck('cut_attack_surface', 'lockdown', 'EFI_TEST', 'is not set')] # refers to LOCKDOWN
463 l += [OptCheck('cut_attack_surface', 'lockdown', 'BPF_SYSCALL', 'is not set')] # refers to LOCKDOWN
464 l += [OptCheck('cut_attack_surface', 'lockdown', 'MMIOTRACE_TEST', 'is not set')] # refers to LOCKDOWN
466 # 'cut_attack_surface', 'clipos'
467 l += [OptCheck('cut_attack_surface', 'clipos', 'STAGING', 'is not set')]
468 l += [OptCheck('cut_attack_surface', 'clipos', 'KSM', 'is not set')] # to prevent FLUSH+RELOAD attack
469 # l += [OptCheck('cut_attack_surface', 'clipos', 'IKCONFIG', 'is not set')] # no, IKCONFIG is needed for this check :)
470 l += [OptCheck('cut_attack_surface', 'clipos', 'KALLSYMS', 'is not set')]
471 l += [OptCheck('cut_attack_surface', 'clipos', 'X86_VSYSCALL_EMULATION', 'is not set')]
472 l += [OptCheck('cut_attack_surface', 'clipos', 'MAGIC_SYSRQ', 'is not set')]
473 l += [OptCheck('cut_attack_surface', 'clipos', 'KEXEC_FILE', 'is not set')] # refers to LOCKDOWN (permissive)
474 l += [OptCheck('cut_attack_surface', 'clipos', 'USER_NS', 'is not set')] # user.max_user_namespaces=0
475 l += [OptCheck('cut_attack_surface', 'clipos', 'X86_MSR', 'is not set')] # refers to LOCKDOWN
476 l += [OptCheck('cut_attack_surface', 'clipos', 'X86_CPUID', 'is not set')]
477 l += [AND(OptCheck('cut_attack_surface', 'clipos', 'LDISC_AUTOLOAD', 'is not set'),
478 PresenceCheck('LDISC_AUTOLOAD'))]
479 if arch in ('X86_64', 'X86_32'):
480 l += [OptCheck('cut_attack_surface', 'clipos', 'X86_INTEL_TSX_MODE_OFF', 'y')] # tsx=off
482 # 'cut_attack_surface', 'grapheneos'
483 l += [OptCheck('cut_attack_surface', 'grapheneos', 'AIO', 'is not set')]
485 # 'cut_attack_surface', 'my'
486 l += [OptCheck('cut_attack_surface', 'my', 'MMIOTRACE', 'is not set')] # refers to LOCKDOWN (permissive)
487 l += [OptCheck('cut_attack_surface', 'my', 'LIVEPATCH', 'is not set')]
488 l += [OptCheck('cut_attack_surface', 'my', 'IP_DCCP', 'is not set')]
489 l += [OptCheck('cut_attack_surface', 'my', 'IP_SCTP', 'is not set')]
490 l += [OptCheck('cut_attack_surface', 'my', 'FTRACE', 'is not set')] # refers to LOCKDOWN
491 l += [OptCheck('cut_attack_surface', 'my', 'BPF_JIT', 'is not set')]
492 l += [OptCheck('cut_attack_surface', 'my', 'VIDEO_VIVID', 'is not set')]
493 l += [OptCheck('cut_attack_surface', 'my', 'INPUT_EVBUG', 'is not set')] # Can be used as a keylogger
495 # 'userspace_hardening'
496 l += [OptCheck('userspace_hardening', 'defconfig', 'INTEGRITY', 'y')]
497 if arch in ('ARM', 'X86_32'):
498 l += [OptCheck('userspace_hardening', 'defconfig', 'VMSPLIT_3G', 'y')]
499 if arch in ('X86_64', 'ARM64'):
500 l += [OptCheck('userspace_hardening', 'clipos', 'ARCH_MMAP_RND_BITS', '32')]
501 if arch in ('X86_32', 'ARM'):
502 l += [OptCheck('userspace_hardening', 'my', 'ARCH_MMAP_RND_BITS', '16')]
504 # l += [OptCheck('feature_test', 'my', 'LKDTM', 'm')] # only for debugging!
507 def print_unknown_options(checklist, parsed_options):
509 for opt in checklist:
510 if hasattr(opt, 'opts'):
512 if hasattr(o, 'name'):
513 known_options.append(o.name)
515 known_options.append(opt.name)
516 for option, value in parsed_options.items():
517 if option not in known_options:
518 print('[?] No rule for option {} ({})'.format(option, value))
521 def print_checklist(mode, checklist, with_results):
525 opt = ['CONFIG_'+o.name, o.expected, o.decision, o.reason]
529 print(json.dumps(opts))
536 print('=' * sep_line_len)
537 print('{:^45}|{:^13}|{:^10}|{:^20}'.format('option name', 'desired val', 'decision', 'reason'), end='')
539 print('| {}'.format('check result'), end='')
541 print('=' * sep_line_len)
544 for opt in checklist:
546 if mode == 'show_ok':
547 if not opt.result.startswith('OK'):
549 if mode == 'show_fail':
550 if not opt.result.startswith('FAIL'):
552 opt.table_print(mode, with_results)
554 if mode == 'verbose':
555 print('-' * sep_line_len)
560 fail_count = len(list(filter(lambda opt: opt.result.startswith('FAIL'), checklist)))
562 ok_count = len(list(filter(lambda opt: opt.result.startswith('OK'), checklist)))
564 if mode == 'show_ok':
565 fail_suppressed = ' (suppressed in output)'
566 if mode == 'show_fail':
567 ok_suppressed = ' (suppressed in output)'
569 print('[+] Config check is finished: \'OK\' - {}{} / \'FAIL\' - {}{}'.format(ok_count, ok_suppressed, fail_count, fail_suppressed))
572 def perform_checks(checklist, parsed_options, kernel_version):
573 for opt in checklist:
574 if hasattr(opt, 'opts'):
575 # prepare ComplexOptCheck
577 if hasattr(o, 'state'):
578 o.state = parsed_options.get(o.name, None)
579 if hasattr(o, 'ver'):
580 o.ver = kernel_version
582 # prepare simple check
583 if not hasattr(opt, 'state'):
584 sys.exit('[!] ERROR: bad simple check {}'.format(vars(opt)))
585 opt.state = parsed_options.get(opt.name, None)
589 def parse_config_file(parsed_options, fname):
590 with open(fname, 'r') as f:
591 opt_is_on = re.compile("CONFIG_[a-zA-Z0-9_]*=[a-zA-Z0-9_\"]*")
592 opt_is_off = re.compile("# CONFIG_[a-zA-Z0-9_]* is not set")
594 for line in f.readlines():
599 if opt_is_on.match(line):
600 option, value = line[7:].split('=', 1)
601 elif opt_is_off.match(line):
602 option, value = line[9:].split(' ', 1)
603 if value != 'is not set':
604 sys.exit('[!] ERROR: bad disabled config option "{}"'.format(line))
606 if option in parsed_options:
607 sys.exit('[!] ERROR: config option "{}" exists multiple times'.format(line))
610 parsed_options[option] = value
612 return parsed_options
618 # - reporting about unknown kernel options in the config
619 # - verbose printing of ComplexOptCheck items
620 # * json mode for printing the results in JSON format
621 report_modes = ['verbose', 'json', 'show_ok', 'show_fail']
622 supported_archs = ['X86_64', 'X86_32', 'ARM64', 'ARM']
623 parser = ArgumentParser(prog='kconfig-hardened-check',
624 description='Checks the hardening options in the Linux kernel config')
625 parser.add_argument('--version', action='version', version='%(prog)s ' + __version__)
626 parser.add_argument('-p', '--print', choices=supported_archs,
627 help='print hardening preferences for selected architecture')
628 parser.add_argument('-c', '--config',
629 help='check the kernel config file against these preferences')
630 parser.add_argument('-m', '--mode', choices=report_modes,
631 help='choose the report mode')
632 args = parser.parse_args()
638 print("[+] Special report mode: {}".format(mode))
640 config_checklist = []
644 print('[+] Config file to check: {}'.format(args.config))
646 arch, msg = detect_arch(args.config, supported_archs)
648 sys.exit('[!] ERROR: {}'.format(msg))
650 print('[+] Detected architecture: {}'.format(arch))
652 kernel_version, msg = detect_version(args.config)
653 if not kernel_version:
654 sys.exit('[!] ERROR: {}'.format(msg))
656 print('[+] Detected kernel version: {}.{}'.format(kernel_version[0], kernel_version[1]))
658 construct_checklist(config_checklist, arch)
659 parsed_options = OrderedDict()
660 parse_config_file(parsed_options, args.config)
661 perform_checks(config_checklist, parsed_options, kernel_version)
663 if mode == 'verbose':
664 print_unknown_options(config_checklist, parsed_options)
665 print_checklist(mode, config_checklist, True)
670 if mode in ('show_ok', 'show_fail'):
671 sys.exit('[!] ERROR: please use "{}" mode for checking the kernel config'.format(mode))
673 construct_checklist(config_checklist, arch)
675 print('[+] Printing kernel hardening preferences for {}...'.format(arch))
676 print_checklist(mode, config_checklist, False)
682 if __name__ == '__main__':