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__init__.py
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__init__.py
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#!/usr/bin/python3
#
# This tool helps me to check the Linux kernel Kconfig option list
# against my security hardening preferences for X86_64, ARM64, X86_32, and ARM.
# Let the computers do their job!
#
# Author: Alexander Popov <alex.popov@linux.com>
#
# Please don't cry if my Python code looks like C.
#
#
# N.B Hardening command line parameters:
# slab_nomerge
# page_alloc.shuffle=1
# iommu=force (does it help against DMA attacks?)
# slub_debug=FZ (slow)
# init_on_alloc=1 (since v5.3)
# init_on_free=1 (since v5.3, otherwise slub_debug=P and page_poison=1)
# loadpin.enforce=1
# debugfs=no-mount (or off if possible)
#
# Mitigations of CPU vulnerabilities:
# Аrch-independent:
# mitigations=auto,nosmt (nosmt is slow)
# X86:
# spectre_v2=on
# pti=on
# spec_store_bypass_disable=on
# l1tf=full,force
# mds=full,nosmt
# tsx=off
# ARM64:
# kpti=on
# ssbd=force-on
#
# Should NOT be set:
# nokaslr
# arm64.nobti
# arm64.nopauth
#
# N.B. Hardening sysctls:
# kernel.kptr_restrict=2 (or 1?)
# kernel.dmesg_restrict=1 (also see the kconfig option)
# kernel.perf_event_paranoid=3
# kernel.kexec_load_disabled=1
# kernel.yama.ptrace_scope=3
# user.max_user_namespaces=0
# what about bpf_jit_enable?
# kernel.unprivileged_bpf_disabled=1
# net.core.bpf_jit_harden=2
#
# vm.unprivileged_userfaultfd=0
# (at first, it disabled unprivileged userfaultfd,
# and since v5.11 it enables unprivileged userfaultfd for user-mode only)
#
# dev.tty.ldisc_autoload=0
# fs.protected_symlinks=1
# fs.protected_hardlinks=1
# fs.protected_fifos=2
# fs.protected_regular=2
# fs.suid_dumpable=0
# kernel.modules_disabled=1
# pylint: disable=missing-module-docstring,missing-class-docstring,missing-function-docstring
# pylint: disable=line-too-long,invalid-name,too-many-branches,too-many-statements
import sys
from argparse import ArgumentParser
from collections import OrderedDict
import re
import json
from .__about__ import __version__
class OptCheck:
def __init__(self, reason, decision, name, expected):
self.name = name
self.expected = expected
self.decision = decision
self.reason = reason
self.state = None
self.result = None
def check(self):
if self.expected == self.state:
self.result = 'OK'
elif self.state is None:
if self.expected == 'is not set':
self.result = 'OK: not found'
else:
self.result = 'FAIL: not found'
else:
self.result = 'FAIL: "' + self.state + '"'
if self.result.startswith('OK'):
return True
return False
def table_print(self, _mode, with_results):
print('CONFIG_{:<38}|{:^13}|{:^10}|{:^20}'.format(self.name, self.expected, self.decision, self.reason), end='')
if with_results:
print('| {}'.format(self.result), end='')
class VerCheck:
def __init__(self, ver_expected):
self.ver_expected = ver_expected
self.ver = ()
self.result = None
def check(self):
if self.ver[0] > self.ver_expected[0]:
self.result = 'OK: version >= ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
return True
if self.ver[0] < self.ver_expected[0]:
self.result = 'FAIL: version < ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
return False
if self.ver[1] >= self.ver_expected[1]:
self.result = 'OK: version >= ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
return True
self.result = 'FAIL: version < ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
return False
def table_print(self, _mode, with_results):
ver_req = 'kernel version >= ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
print('{:<91}'.format(ver_req), end='')
if with_results:
print('| {}'.format(self.result), end='')
class PresenceCheck:
def __init__(self, name):
self.name = name
self.state = None
self.result = None
def check(self):
if self.state is None:
self.result = 'FAIL: not present'
return False
self.result = 'OK: is present'
return True
def table_print(self, _mode, with_results):
print('CONFIG_{:<84}'.format(self.name + ' is present'), end='')
if with_results:
print('| {}'.format(self.result), end='')
class ComplexOptCheck:
def __init__(self, *opts):
self.opts = opts
if not self.opts:
sys.exit('[!] ERROR: empty {} check'.format(self.__class__.__name__))
if not isinstance(opts[0], OptCheck):
sys.exit('[!] ERROR: invalid {} check: {}'.format(self.__class__.__name__, opts))
self.result = None
@property
def name(self):
return self.opts[0].name
@property
def expected(self):
return self.opts[0].expected
@property
def decision(self):
return self.opts[0].decision
@property
def reason(self):
return self.opts[0].reason
def table_print(self, mode, with_results):
if mode == 'verbose':
print(' {:87}'.format('<<< ' + self.__class__.__name__ + ' >>>'), end='')
if with_results:
print('| {}'.format(self.result), end='')
for o in self.opts:
print()
o.table_print(mode, with_results)
else:
o = self.opts[0]
o.table_print(mode, False)
if with_results:
print('| {}'.format(self.result), end='')
class OR(ComplexOptCheck):
# self.opts[0] is the option that this OR-check is about.
# Use cases:
# OR(<X_is_hardened>, <X_is_disabled>)
# OR(<X_is_hardened>, <old_X_is_hardened>)
def check(self):
if not self.opts:
sys.exit('[!] ERROR: invalid OR check')
for i, opt in enumerate(self.opts):
ret = opt.check()
if ret:
if opt.result != 'OK' or i == 0:
# Preserve additional explanation of this OK result.
# Simple OK is enough only for the main option that
# this OR-check is about.
self.result = opt.result
else:
# Simple OK is not enough for additional checks.
self.result = 'OK: CONFIG_{} "{}"'.format(opt.name, opt.expected)
return True
self.result = self.opts[0].result
return False
class AND(ComplexOptCheck):
# self.opts[0] is the option that this AND-check is about.
# Use cases:
# AND(<suboption>, <main_option>)
# Suboption is not checked if checking of the main_option is failed.
# AND(<X_is_disabled>, <old_X_is_disabled>)
def check(self):
for i, opt in reversed(list(enumerate(self.opts))):
ret = opt.check()
if i == 0:
self.result = opt.result
return ret
if not ret:
# This FAIL is caused by additional checks,
# and not by the main option that this AND-check is about.
# Describe the reason of the FAIL.
if opt.result.startswith('FAIL: \"') or opt.result == 'FAIL: not found':
self.result = 'FAIL: CONFIG_{} not "{}"'.format(opt.name, opt.expected)
elif opt.result == 'FAIL: not present':
self.result = 'FAIL: CONFIG_{} not present'.format(opt.name)
else:
# This FAIL message is self-explaining.
self.result = opt.result
return False
sys.exit('[!] ERROR: invalid AND check')
def detect_arch(fname, archs):
with open(fname, 'r') as f:
arch_pattern = re.compile("CONFIG_[a-zA-Z0-9_]*=y")
arch = None
for line in f.readlines():
if arch_pattern.match(line):
option, _ = line[7:].split('=', 1)
if option in archs:
if not arch:
arch = option
else:
return None, 'more than one supported architecture is detected'
if not arch:
return None, 'failed to detect architecture'
return arch, 'OK'
def detect_version(fname):
with open(fname, 'r') as f:
ver_pattern = re.compile("# Linux/.* Kernel Configuration")
for line in f.readlines():
if ver_pattern.match(line):
line = line.strip()
parts = line.split()
ver_str = parts[2]
ver_numbers = ver_str.split('.')
if len(ver_numbers) < 3 or not ver_numbers[0].isdigit() or not ver_numbers[1].isdigit():
msg = 'failed to parse the version "' + ver_str + '"'
return None, msg
return (int(ver_numbers[0]), int(ver_numbers[1])), None
return None, 'no kernel version detected'
def construct_checklist(l, arch):
modules_not_set = OptCheck('cut_attack_surface', 'kspp', 'MODULES', 'is not set')
devmem_not_set = OptCheck('cut_attack_surface', 'kspp', 'DEVMEM', 'is not set') # refers to LOCKDOWN
# 'self_protection', 'defconfig'
l += [OptCheck('self_protection', 'defconfig', 'BUG', 'y')]
l += [OptCheck('self_protection', 'defconfig', 'SLUB_DEBUG', 'y')]
l += [OptCheck('self_protection', 'defconfig', 'GCC_PLUGINS', 'y')]
l += [OR(OptCheck('self_protection', 'defconfig', 'STACKPROTECTOR_STRONG', 'y'),
OptCheck('self_protection', 'defconfig', 'CC_STACKPROTECTOR_STRONG', 'y'))]
l += [OR(OptCheck('self_protection', 'defconfig', 'STRICT_KERNEL_RWX', 'y'),
OptCheck('self_protection', 'defconfig', 'DEBUG_RODATA', 'y'))] # before v4.11
l += [OR(OptCheck('self_protection', 'defconfig', 'STRICT_MODULE_RWX', 'y'),
OptCheck('self_protection', 'defconfig', 'DEBUG_SET_MODULE_RONX', 'y'),
modules_not_set)] # DEBUG_SET_MODULE_RONX was before v4.11
l += [OR(OptCheck('self_protection', 'defconfig', 'REFCOUNT_FULL', 'y'),
VerCheck((5, 5)))] # REFCOUNT_FULL is enabled by default since v5.5
iommu_support_is_set = OptCheck('self_protection', 'defconfig', 'IOMMU_SUPPORT', 'y')
l += [iommu_support_is_set] # is needed for mitigating DMA attacks
if arch in ('X86_64', 'ARM64', 'X86_32'):
l += [OptCheck('self_protection', 'defconfig', 'RANDOMIZE_BASE', 'y')]
l += [OptCheck('self_protection', 'defconfig', 'THREAD_INFO_IN_TASK', 'y')]
if arch in ('X86_64', 'ARM64'):
l += [OptCheck('self_protection', 'defconfig', 'VMAP_STACK', 'y')]
if arch in ('X86_64', 'X86_32'):
l += [OptCheck('self_protection', 'defconfig', 'MICROCODE', 'y')] # is needed for mitigating CPU bugs
l += [OptCheck('self_protection', 'defconfig', 'RETPOLINE', 'y')]
l += [OptCheck('self_protection', 'defconfig', 'X86_SMAP', 'y')]
l += [OptCheck('self_protection', 'defconfig', 'SYN_COOKIES', 'y')] # another reason?
l += [OR(OptCheck('self_protection', 'defconfig', 'X86_UMIP', 'y'),
OptCheck('self_protection', 'defconfig', 'X86_INTEL_UMIP', 'y'))]
if arch in ('ARM64', 'ARM'):
l += [OptCheck('self_protection', 'defconfig', 'STACKPROTECTOR_PER_TASK', 'y')]
if arch == 'X86_64':
l += [OptCheck('self_protection', 'defconfig', 'PAGE_TABLE_ISOLATION', 'y')]
l += [OptCheck('self_protection', 'defconfig', 'RANDOMIZE_MEMORY', 'y')]
l += [AND(OptCheck('self_protection', 'defconfig', 'INTEL_IOMMU', 'y'),
iommu_support_is_set)]
l += [AND(OptCheck('self_protection', 'defconfig', 'AMD_IOMMU', 'y'),
iommu_support_is_set)]
if arch == 'ARM64':
l += [OptCheck('self_protection', 'defconfig', 'ARM64_PAN', 'y')]
l += [OptCheck('self_protection', 'defconfig', 'UNMAP_KERNEL_AT_EL0', 'y')]
l += [OR(OptCheck('self_protection', 'defconfig', 'HARDEN_EL2_VECTORS', 'y'),
AND(OptCheck('self_protection', 'defconfig', 'RANDOMIZE_BASE', 'y'),
VerCheck((5, 9))))] # HARDEN_EL2_VECTORS was included in RANDOMIZE_BASE in v5.9
l += [OptCheck('self_protection', 'defconfig', 'RODATA_FULL_DEFAULT_ENABLED', 'y')]
l += [OptCheck('self_protection', 'defconfig', 'ARM64_PTR_AUTH', 'y')]
l += [OptCheck('self_protection', 'defconfig', 'ARM64_BTI_KERNEL', 'y')]
l += [OR(OptCheck('self_protection', 'defconfig', 'HARDEN_BRANCH_PREDICTOR', 'y'),
VerCheck((5, 10)))] # HARDEN_BRANCH_PREDICTOR is enabled by default since v5.10
if arch == 'ARM':
l += [OptCheck('self_protection', 'defconfig', 'CPU_SW_DOMAIN_PAN', 'y')]
l += [OptCheck('self_protection', 'defconfig', 'HARDEN_BRANCH_PREDICTOR', 'y')]
# 'self_protection', 'kspp'
l += [OptCheck('self_protection', 'kspp', 'SECURITY_DMESG_RESTRICT', 'y')]
l += [OptCheck('self_protection', 'kspp', 'BUG_ON_DATA_CORRUPTION', 'y')]
l += [OptCheck('self_protection', 'kspp', 'DEBUG_WX', 'y')]
l += [OptCheck('self_protection', 'kspp', 'SCHED_STACK_END_CHECK', 'y')]
l += [OptCheck('self_protection', 'kspp', 'SLAB_FREELIST_HARDENED', 'y')]
l += [OptCheck('self_protection', 'kspp', 'SLAB_FREELIST_RANDOM', 'y')]
l += [OptCheck('self_protection', 'kspp', 'SHUFFLE_PAGE_ALLOCATOR', 'y')]
l += [OptCheck('self_protection', 'kspp', 'FORTIFY_SOURCE', 'y')]
l += [OptCheck('self_protection', 'kspp', 'DEBUG_LIST', 'y')]
l += [OptCheck('self_protection', 'kspp', 'DEBUG_SG', 'y')]
l += [OptCheck('self_protection', 'kspp', 'DEBUG_CREDENTIALS', 'y')]
l += [OptCheck('self_protection', 'kspp', 'DEBUG_NOTIFIERS', 'y')]
l += [OptCheck('self_protection', 'kspp', 'INIT_ON_ALLOC_DEFAULT_ON', 'y')]
l += [OptCheck('self_protection', 'kspp', 'GCC_PLUGIN_LATENT_ENTROPY', 'y')]
randstruct_is_set = OptCheck('self_protection', 'kspp', 'GCC_PLUGIN_RANDSTRUCT', 'y')
l += [randstruct_is_set]
hardened_usercopy_is_set = OptCheck('self_protection', 'kspp', 'HARDENED_USERCOPY', 'y')
l += [hardened_usercopy_is_set]
l += [AND(OptCheck('self_protection', 'kspp', 'HARDENED_USERCOPY_FALLBACK', 'is not set'),
hardened_usercopy_is_set)]
l += [OR(OptCheck('self_protection', 'kspp', 'MODULE_SIG', 'y'),
modules_not_set)]
l += [OR(OptCheck('self_protection', 'kspp', 'MODULE_SIG_ALL', 'y'),
modules_not_set)]
l += [OR(OptCheck('self_protection', 'kspp', 'MODULE_SIG_SHA512', 'y'),
modules_not_set)]
l += [OR(OptCheck('self_protection', 'kspp', 'MODULE_SIG_FORCE', 'y'),
modules_not_set)] # refers to LOCKDOWN
l += [OR(OptCheck('self_protection', 'kspp', 'INIT_STACK_ALL_ZERO', 'y'),
OptCheck('self_protection', 'kspp', 'GCC_PLUGIN_STRUCTLEAK_BYREF_ALL', 'y'))]
l += [OR(OptCheck('self_protection', 'kspp', 'INIT_ON_FREE_DEFAULT_ON', 'y'),
OptCheck('self_protection', 'kspp', 'PAGE_POISONING_ZERO', 'y'))]
# CONFIG_INIT_ON_FREE_DEFAULT_ON was added in v5.3.
# CONFIG_PAGE_POISONING_ZERO was removed in v5.11.
# Starting from v5.11 CONFIG_PAGE_POISONING unconditionally checks
# the 0xAA poison pattern on allocation.
# That brings higher performance penalty.
if arch in ('X86_64', 'ARM64', 'X86_32'):
stackleak_is_set = OptCheck('self_protection', 'kspp', 'GCC_PLUGIN_STACKLEAK', 'y')
l += [stackleak_is_set]
if arch in ('X86_64', 'X86_32'):
l += [OptCheck('self_protection', 'kspp', 'DEFAULT_MMAP_MIN_ADDR', '65536')]
if arch in ('ARM64', 'ARM'):
l += [OptCheck('self_protection', 'kspp', 'DEFAULT_MMAP_MIN_ADDR', '32768')]
l += [OptCheck('self_protection', 'kspp', 'SYN_COOKIES', 'y')] # another reason?
if arch == 'ARM64':
l += [OptCheck('self_protection', 'kspp', 'ARM64_SW_TTBR0_PAN', 'y')]
if arch == 'X86_32':
l += [OptCheck('self_protection', 'kspp', 'PAGE_TABLE_ISOLATION', 'y')]
l += [OptCheck('self_protection', 'kspp', 'HIGHMEM64G', 'y')]
l += [OptCheck('self_protection', 'kspp', 'X86_PAE', 'y')]
# 'self_protection', 'clipos'
l += [OptCheck('self_protection', 'clipos', 'DEBUG_VIRTUAL', 'y')]
l += [OptCheck('self_protection', 'clipos', 'STATIC_USERMODEHELPER', 'y')] # needs userspace support
l += [OptCheck('self_protection', 'clipos', 'EFI_DISABLE_PCI_DMA', 'y')]
l += [OptCheck('self_protection', 'clipos', 'SLAB_MERGE_DEFAULT', 'is not set')] # slab_nomerge
l += [OptCheck('self_protection', 'clipos', 'RANDOM_TRUST_BOOTLOADER', 'is not set')]
l += [OptCheck('self_protection', 'clipos', 'RANDOM_TRUST_CPU', 'is not set')]
l += [AND(OptCheck('self_protection', 'clipos', 'GCC_PLUGIN_RANDSTRUCT_PERFORMANCE', 'is not set'),
randstruct_is_set)]
if arch in ('X86_64', 'ARM64', 'X86_32'):
l += [AND(OptCheck('self_protection', 'clipos', 'STACKLEAK_METRICS', 'is not set'),
stackleak_is_set)]
l += [AND(OptCheck('self_protection', 'clipos', 'STACKLEAK_RUNTIME_DISABLE', 'is not set'),
stackleak_is_set)]
if arch in ('X86_64', 'X86_32'):
l += [AND(OptCheck('self_protection', 'clipos', 'INTEL_IOMMU_DEFAULT_ON', 'y'),
iommu_support_is_set)]
if arch == 'X86_64':
l += [AND(OptCheck('self_protection', 'clipos', 'INTEL_IOMMU_SVM', 'y'),
iommu_support_is_set)]
if arch == 'X86_32':
l += [AND(OptCheck('self_protection', 'clipos', 'INTEL_IOMMU', 'y'),
iommu_support_is_set)]
# 'self_protection', 'my'
l += [AND(OptCheck('self_protection', 'my', 'UBSAN_BOUNDS', 'y'),
OptCheck('self_protection', 'my', 'UBSAN_MISC', 'is not set'),
OptCheck('self_protection', 'my', 'UBSAN_TRAP', 'y'))]
l += [OptCheck('self_protection', 'my', 'RESET_ATTACK_MITIGATION', 'y')] # needs userspace support (systemd)
if arch == 'X86_64':
l += [AND(OptCheck('self_protection', 'my', 'AMD_IOMMU_V2', 'y'),
iommu_support_is_set)]
if arch == 'ARM64':
l += [OptCheck('self_protection', 'my', 'SHADOW_CALL_STACK', 'y')] # depends on clang, maybe it's alternative to STACKPROTECTOR_STRONG
# 'security_policy'
if arch in ('X86_64', 'ARM64', 'X86_32'):
l += [OptCheck('security_policy', 'defconfig', 'SECURITY', 'y')] # and choose your favourite LSM
if arch == 'ARM':
l += [OptCheck('security_policy', 'kspp', 'SECURITY', 'y')] # and choose your favourite LSM
l += [OptCheck('security_policy', 'kspp', 'SECURITY_YAMA', 'y')]
l += [OR(OptCheck('security_policy', 'my', 'SECURITY_WRITABLE_HOOKS', 'is not set'),
OptCheck('security_policy', 'kspp', 'SECURITY_SELINUX_DISABLE', 'is not set'))]
l += [OptCheck('security_policy', 'clipos', 'SECURITY_LOCKDOWN_LSM', 'y')]
l += [OptCheck('security_policy', 'clipos', 'SECURITY_LOCKDOWN_LSM_EARLY', 'y')]
l += [OptCheck('security_policy', 'clipos', 'LOCK_DOWN_KERNEL_FORCE_CONFIDENTIALITY', 'y')]
l += [OptCheck('security_policy', 'my', 'SECURITY_SAFESETID', 'y')]
loadpin_is_set = OptCheck('security_policy', 'my', 'SECURITY_LOADPIN', 'y')
l += [loadpin_is_set] # needs userspace support
l += [AND(OptCheck('security_policy', 'my', 'SECURITY_LOADPIN_ENFORCE', 'y'),
loadpin_is_set)]
# 'cut_attack_surface', 'defconfig'
l += [OptCheck('cut_attack_surface', 'defconfig', 'SECCOMP', 'y')]
l += [OptCheck('cut_attack_surface', 'defconfig', 'SECCOMP_FILTER', 'y')]
if arch in ('X86_64', 'ARM64', 'X86_32'):
l += [OR(OptCheck('cut_attack_surface', 'defconfig', 'STRICT_DEVMEM', 'y'),
devmem_not_set)] # refers to LOCKDOWN
# 'cut_attack_surface', 'kspp'
l += [OptCheck('cut_attack_surface', 'kspp', 'ACPI_CUSTOM_METHOD', 'is not set')] # refers to LOCKDOWN
l += [OptCheck('cut_attack_surface', 'kspp', 'COMPAT_BRK', 'is not set')]
l += [OptCheck('cut_attack_surface', 'kspp', 'DEVKMEM', 'is not set')] # refers to LOCKDOWN
l += [OptCheck('cut_attack_surface', 'kspp', 'COMPAT_VDSO', 'is not set')]
l += [OptCheck('cut_attack_surface', 'kspp', 'BINFMT_MISC', 'is not set')]
l += [OptCheck('cut_attack_surface', 'kspp', 'INET_DIAG', 'is not set')]
l += [OptCheck('cut_attack_surface', 'kspp', 'KEXEC', 'is not set')] # refers to LOCKDOWN
l += [OptCheck('cut_attack_surface', 'kspp', 'PROC_KCORE', 'is not set')] # refers to LOCKDOWN
l += [OptCheck('cut_attack_surface', 'kspp', 'LEGACY_PTYS', 'is not set')]
l += [OptCheck('cut_attack_surface', 'kspp', 'HIBERNATION', 'is not set')] # refers to LOCKDOWN
l += [OptCheck('cut_attack_surface', 'kspp', 'IA32_EMULATION', 'is not set')]
l += [OptCheck('cut_attack_surface', 'kspp', 'X86_X32', 'is not set')]
l += [OptCheck('cut_attack_surface', 'kspp', 'MODIFY_LDT_SYSCALL', 'is not set')]
l += [OptCheck('cut_attack_surface', 'kspp', 'OABI_COMPAT', 'is not set')]
l += [modules_not_set]
l += [devmem_not_set]
l += [OR(OptCheck('cut_attack_surface', 'kspp', 'IO_STRICT_DEVMEM', 'y'),
devmem_not_set)] # refers to LOCKDOWN
if arch == 'ARM':
l += [OR(OptCheck('cut_attack_surface', 'kspp', 'STRICT_DEVMEM', 'y'),
devmem_not_set)] # refers to LOCKDOWN
if arch == 'X86_64':
l += [OptCheck('cut_attack_surface', 'kspp', 'LEGACY_VSYSCALL_NONE', 'y')] # 'vsyscall=none'
# 'cut_attack_surface', 'grsecurity'
l += [OptCheck('cut_attack_surface', 'grsecurity', 'ZSMALLOC_STAT', 'is not set')]
l += [OptCheck('cut_attack_surface', 'grsecurity', 'PAGE_OWNER', 'is not set')]
l += [OptCheck('cut_attack_surface', 'grsecurity', 'DEBUG_KMEMLEAK', 'is not set')]
l += [OptCheck('cut_attack_surface', 'grsecurity', 'BINFMT_AOUT', 'is not set')]
l += [OptCheck('cut_attack_surface', 'grsecurity', 'KPROBES', 'is not set')] # refers to LOCKDOWN
l += [OptCheck('cut_attack_surface', 'grsecurity', 'UPROBES', 'is not set')]
l += [OptCheck('cut_attack_surface', 'grsecurity', 'GENERIC_TRACER', 'is not set')] # refers to LOCKDOWN
l += [OptCheck('cut_attack_surface', 'grsecurity', 'PROC_VMCORE', 'is not set')]
l += [OptCheck('cut_attack_surface', 'grsecurity', 'PROC_PAGE_MONITOR', 'is not set')]
l += [OptCheck('cut_attack_surface', 'grsecurity', 'USELIB', 'is not set')]
l += [OptCheck('cut_attack_surface', 'grsecurity', 'CHECKPOINT_RESTORE', 'is not set')]
l += [OptCheck('cut_attack_surface', 'grsecurity', 'USERFAULTFD', 'is not set')]
l += [OptCheck('cut_attack_surface', 'grsecurity', 'HWPOISON_INJECT', 'is not set')]
l += [OptCheck('cut_attack_surface', 'grsecurity', 'MEM_SOFT_DIRTY', 'is not set')]
l += [OptCheck('cut_attack_surface', 'grsecurity', 'DEVPORT', 'is not set')] # refers to LOCKDOWN
l += [OptCheck('cut_attack_surface', 'grsecurity', 'DEBUG_FS', 'is not set')] # refers to LOCKDOWN
l += [OptCheck('cut_attack_surface', 'grsecurity', 'NOTIFIER_ERROR_INJECTION', 'is not set')]
l += [AND(OptCheck('cut_attack_surface', 'grsecurity', 'X86_PTDUMP', 'is not set'),
OptCheck('cut_attack_surface', 'my', 'PTDUMP_DEBUGFS', 'is not set'))]
# 'cut_attack_surface', 'maintainer'
l += [OptCheck('cut_attack_surface', 'maintainer', 'DRM_LEGACY', 'is not set')]
l += [OptCheck('cut_attack_surface', 'maintainer', 'FB', 'is not set')]
l += [OptCheck('cut_attack_surface', 'maintainer', 'VT', 'is not set')]
# 'cut_attack_surface', 'grapheneos'
l += [OptCheck('cut_attack_surface', 'grapheneos', 'AIO', 'is not set')]
# 'cut_attack_surface', 'clipos'
l += [OptCheck('cut_attack_surface', 'clipos', 'STAGING', 'is not set')]
l += [OptCheck('cut_attack_surface', 'clipos', 'KSM', 'is not set')] # to prevent FLUSH+RELOAD attack
# l += [OptCheck('cut_attack_surface', 'clipos', 'IKCONFIG', 'is not set')] # no, IKCONFIG is needed for this check :)
l += [OptCheck('cut_attack_surface', 'clipos', 'KALLSYMS', 'is not set')]
l += [OptCheck('cut_attack_surface', 'clipos', 'X86_VSYSCALL_EMULATION', 'is not set')]
l += [OptCheck('cut_attack_surface', 'clipos', 'MAGIC_SYSRQ', 'is not set')]
l += [OptCheck('cut_attack_surface', 'clipos', 'KEXEC_FILE', 'is not set')] # refers to LOCKDOWN (permissive)
l += [OptCheck('cut_attack_surface', 'clipos', 'USER_NS', 'is not set')] # user.max_user_namespaces=0
l += [OptCheck('cut_attack_surface', 'clipos', 'X86_MSR', 'is not set')] # refers to LOCKDOWN
l += [OptCheck('cut_attack_surface', 'clipos', 'X86_CPUID', 'is not set')]
l += [OptCheck('cut_attack_surface', 'clipos', 'IO_URING', 'is not set')]
l += [OptCheck('cut_attack_surface', 'clipos', 'X86_IOPL_IOPERM', 'is not set')] # refers to LOCKDOWN
l += [OptCheck('cut_attack_surface', 'clipos', 'ACPI_TABLE_UPGRADE', 'is not set')] # refers to LOCKDOWN
l += [OptCheck('cut_attack_surface', 'clipos', 'EFI_CUSTOM_SSDT_OVERLAYS', 'is not set')]
l += [AND(OptCheck('cut_attack_surface', 'clipos', 'LDISC_AUTOLOAD', 'is not set'),
PresenceCheck('LDISC_AUTOLOAD'))]
if arch in ('X86_64', 'X86_32'):
l += [OptCheck('cut_attack_surface', 'clipos', 'X86_INTEL_TSX_MODE_OFF', 'y')] # tsx=off
# 'cut_attack_surface', 'lockdown'
l += [OptCheck('cut_attack_surface', 'lockdown', 'EFI_TEST', 'is not set')] # refers to LOCKDOWN
l += [OptCheck('cut_attack_surface', 'lockdown', 'BPF_SYSCALL', 'is not set')] # refers to LOCKDOWN
l += [OptCheck('cut_attack_surface', 'lockdown', 'MMIOTRACE_TEST', 'is not set')] # refers to LOCKDOWN
# 'cut_attack_surface', 'my'
l += [OptCheck('cut_attack_surface', 'my', 'TRIM_UNUSED_KSYMS', 'y')]
l += [OptCheck('cut_attack_surface', 'my', 'MMIOTRACE', 'is not set')] # refers to LOCKDOWN (permissive)
l += [OptCheck('cut_attack_surface', 'my', 'LIVEPATCH', 'is not set')]
l += [OptCheck('cut_attack_surface', 'my', 'IP_DCCP', 'is not set')]
l += [OptCheck('cut_attack_surface', 'my', 'IP_SCTP', 'is not set')]
l += [OptCheck('cut_attack_surface', 'my', 'FTRACE', 'is not set')] # refers to LOCKDOWN
l += [OptCheck('cut_attack_surface', 'my', 'VIDEO_VIVID', 'is not set')]
l += [OptCheck('cut_attack_surface', 'my', 'INPUT_EVBUG', 'is not set')] # Can be used as a keylogger
# 'userspace_hardening'
if arch in ('X86_64', 'ARM64', 'X86_32'):
l += [OptCheck('userspace_hardening', 'defconfig', 'INTEGRITY', 'y')]
if arch == 'ARM':
l += [OptCheck('userspace_hardening', 'my', 'INTEGRITY', 'y')]
if arch == 'ARM64':
l += [OptCheck('userspace_hardening', 'defconfig', 'ARM64_MTE', 'y')]
if arch in ('ARM', 'X86_32'):
l += [OptCheck('userspace_hardening', 'defconfig', 'VMSPLIT_3G', 'y')]
if arch in ('X86_64', 'ARM64'):
l += [OptCheck('userspace_hardening', 'clipos', 'ARCH_MMAP_RND_BITS', '32')]
if arch in ('X86_32', 'ARM'):
l += [OptCheck('userspace_hardening', 'my', 'ARCH_MMAP_RND_BITS', '16')]
# l += [OptCheck('feature_test', 'my', 'LKDTM', 'm')] # only for debugging!
def print_unknown_options(checklist, parsed_options):
known_options = []
for opt in checklist:
if hasattr(opt, 'opts'):
for o in opt.opts:
if hasattr(o, 'name'):
known_options.append(o.name)
else:
known_options.append(opt.name)
for option, value in parsed_options.items():
if option not in known_options:
print('[?] No rule for option {} ({})'.format(option, value))
def print_checklist(mode, checklist, with_results):
if mode == 'json':
opts = []
for o in checklist:
opt = ['CONFIG_'+o.name, o.expected, o.decision, o.reason]
if with_results:
opt.append(o.result)
opts.append(opt)
print(json.dumps(opts))
return
# table header
sep_line_len = 91
if with_results:
sep_line_len += 30
print('=' * sep_line_len)
print('{:^45}|{:^13}|{:^10}|{:^20}'.format('option name', 'desired val', 'decision', 'reason'), end='')
if with_results:
print('| {}'.format('check result'), end='')
print()
print('=' * sep_line_len)
# table contents
for opt in checklist:
if with_results:
if mode == 'show_ok':
if not opt.result.startswith('OK'):
continue
if mode == 'show_fail':
if not opt.result.startswith('FAIL'):
continue
opt.table_print(mode, with_results)
print()
if mode == 'verbose':
print('-' * sep_line_len)
print()
# final score
if with_results:
fail_count = len(list(filter(lambda opt: opt.result.startswith('FAIL'), checklist)))
fail_suppressed = ''
ok_count = len(list(filter(lambda opt: opt.result.startswith('OK'), checklist)))
ok_suppressed = ''
if mode == 'show_ok':
fail_suppressed = ' (suppressed in output)'
if mode == 'show_fail':
ok_suppressed = ' (suppressed in output)'
if mode != 'json':
print('[+] Config check is finished: \'OK\' - {}{} / \'FAIL\' - {}{}'.format(ok_count, ok_suppressed, fail_count, fail_suppressed))
def perform_check(opt, parsed_options, kernel_version):
if hasattr(opt, 'opts'):
# prepare ComplexOptCheck
for o in opt.opts:
if hasattr(o, 'opts'):
# Recursion for nested ComplexOptChecks
perform_check(o, parsed_options, kernel_version)
if hasattr(o, 'state'):
o.state = parsed_options.get(o.name, None)
if hasattr(o, 'ver'):
o.ver = kernel_version
else:
# prepare simple check, opt.state is mandatory
if not hasattr(opt, 'state'):
sys.exit('[!] ERROR: bad simple check {}'.format(vars(opt)))
opt.state = parsed_options.get(opt.name, None)
opt.check()
def perform_checks(checklist, parsed_options, kernel_version):
for opt in checklist:
perform_check(opt, parsed_options, kernel_version)
def parse_config_file(parsed_options, fname):
with open(fname, 'r') as f:
opt_is_on = re.compile("CONFIG_[a-zA-Z0-9_]*=[a-zA-Z0-9_\"]*")
opt_is_off = re.compile("# CONFIG_[a-zA-Z0-9_]* is not set")
for line in f.readlines():
line = line.strip()
option = None
value = None
if opt_is_on.match(line):
option, value = line[7:].split('=', 1)
elif opt_is_off.match(line):
option, value = line[9:].split(' ', 1)
if value != 'is not set':
sys.exit('[!] ERROR: bad disabled config option "{}"'.format(line))
if option in parsed_options:
sys.exit('[!] ERROR: config option "{}" exists multiple times'.format(line))
if option:
parsed_options[option] = value
return parsed_options
def main():
# Report modes:
# * verbose mode for
# - reporting about unknown kernel options in the config
# - verbose printing of ComplexOptCheck items
# * json mode for printing the results in JSON format
report_modes = ['verbose', 'json', 'show_ok', 'show_fail']
supported_archs = ['X86_64', 'X86_32', 'ARM64', 'ARM']
parser = ArgumentParser(prog='kconfig-hardened-check',
description='A tool for checking the security hardening options of the Linux kernel')
parser.add_argument('--version', action='version', version='%(prog)s ' + __version__)
parser.add_argument('-p', '--print', choices=supported_archs,
help='print security hardening preferences for the selected architecture')
parser.add_argument('-c', '--config',
help='check the kernel config file against these preferences')
parser.add_argument('-m', '--mode', choices=report_modes,
help='choose the report mode')
args = parser.parse_args()
mode = None
if args.mode:
mode = args.mode
if mode != 'json':
print("[+] Special report mode: {}".format(mode))
config_checklist = []
if args.config:
if mode != 'json':
print('[+] Config file to check: {}'.format(args.config))
arch, msg = detect_arch(args.config, supported_archs)
if not arch:
sys.exit('[!] ERROR: {}'.format(msg))
if mode != 'json':
print('[+] Detected architecture: {}'.format(arch))
kernel_version, msg = detect_version(args.config)
if not kernel_version:
sys.exit('[!] ERROR: {}'.format(msg))
if mode != 'json':
print('[+] Detected kernel version: {}.{}'.format(kernel_version[0], kernel_version[1]))
construct_checklist(config_checklist, arch)
parsed_options = OrderedDict()
parse_config_file(parsed_options, args.config)
perform_checks(config_checklist, parsed_options, kernel_version)
if mode == 'verbose':
print_unknown_options(config_checklist, parsed_options)
print_checklist(mode, config_checklist, True)
sys.exit(0)
if args.print:
if mode in ('show_ok', 'show_fail'):
sys.exit('[!] ERROR: please use "{}" mode for checking the kernel config'.format(mode))
arch = args.print
construct_checklist(config_checklist, arch)
if mode != 'json':
print('[+] Printing kernel security hardening preferences for {}...'.format(arch))
print_checklist(mode, config_checklist, False)
sys.exit(0)
parser.print_help()
sys.exit(0)
if __name__ == '__main__':
main()