#!/usr/bin/python3
-#
-# This tool helps me to check the Linux kernel Kconfig option list
-# against my 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:
-# slub_debug=FZP
-# slab_nomerge
-# page_alloc.shuffle=1
-# iommu=force (does it help against DMA attacks?)
-# page_poison=1 (if enabled)
-# init_on_alloc=1
-# init_on_free=1
-# loadpin.enforce=1
-#
-# Mitigations of CPU vulnerabilities:
-# Аrch-independent:
-# mitigations=auto,nosmt
-# 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
-#
-# N.B. Hardening sysctls:
-# kernel.kptr_restrict=2
-# kernel.dmesg_restrict=1
-# 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
-#
-# 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
+"""
+This tool helps me to check Linux kernel options 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>
+This module performs input/output.
+"""
+
+# pylint: disable=missing-function-docstring,line-too-long,invalid-name,too-many-branches,too-many-statements
+
+import gzip
import sys
from argparse import ArgumentParser
from collections import OrderedDict
import re
import json
from .__about__ import __version__
+from .checks import add_kconfig_checks, add_cmdline_checks, normalize_cmdline_options
+from .engine import populate_with_data, perform_checks
-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 _open(file: str, *args, **kwargs):
+ open_method = open
+ if file.endswith(".gz"):
+ open_method = gzip.open
- 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.
- if opt.result.startswith('FAIL: \"'):
- # Describe the reason of the FAIL.
- self.result = 'FAIL: CONFIG_{} not "{}"'.format(opt.name, opt.expected)
- else:
- # This FAIL message is self-explaining.
- self.result = opt.result
- return False
-
- sys.exit('[!] ERROR: invalid AND check')
+ return open_method(file, *args, **kwargs)
def detect_arch(fname, archs):
- with open(fname, 'r') as f:
+ with _open(fname, 'rt', encoding='utf-8') 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:
+ if arch is None:
arch = option
else:
return None, 'more than one supported architecture is detected'
- if not arch:
+ if arch is None:
return None, 'failed to detect architecture'
return arch, 'OK'
-def detect_version(fname):
- with open(fname, 'r') as f:
+def detect_kernel_version(fname):
+ with _open(fname, 'rt', encoding='utf-8') as f:
ver_pattern = re.compile("# Linux/.* Kernel Configuration")
for line in f.readlines():
if ver_pattern.match(line):
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 + '"'
+ msg = f'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', '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 == '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'),
- VerCheck((5,9)))] # HARDEN_EL2_VECTORS was removed in v5.9
- l += [OptCheck('self_protection', 'defconfig', 'RODATA_FULL_DEFAULT_ENABLED', 'y')]
- l += [OptCheck('self_protection', 'defconfig', 'ARM64_PTR_AUTH', 'y')]
- if arch in ('X86_64', 'ARM64'):
- l += [OptCheck('self_protection', 'defconfig', 'VMAP_STACK', 'y')]
- 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 == 'ARM':
- l += [OptCheck('self_protection', 'defconfig', 'CPU_SW_DOMAIN_PAN', 'y')]
- l += [OptCheck('self_protection', 'defconfig', 'STACKPROTECTOR_PER_TASK', 'y')]
- if arch in ('ARM64', 'ARM'):
- l += [OptCheck('self_protection', 'defconfig', 'HARDEN_BRANCH_PREDICTOR', 'y')]
-
- # 'self_protection', 'kspp'
- 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', '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', 'y'))] # before v5.3
- 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 == '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')]
- if arch == 'ARM64':
- l += [OptCheck('self_protection', 'kspp', 'ARM64_SW_TTBR0_PAN', 'y')]
- if arch in ('ARM64', 'ARM'):
- l += [OptCheck('self_protection', 'kspp', 'SYN_COOKIES', 'y')] # another reason?
- l += [OptCheck('self_protection', 'kspp', 'DEFAULT_MMAP_MIN_ADDR', '32768')]
-
- # 'self_protection', 'clipos'
- l += [OptCheck('self_protection', 'clipos', 'SECURITY_DMESG_RESTRICT', 'y')]
- 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_SVM', 'y'),
- iommu_support_is_set)]
- l += [AND(OptCheck('self_protection', 'clipos', 'INTEL_IOMMU_DEFAULT_ON', '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 += [OptCheck('self_protection', 'my', 'SLUB_DEBUG_ON', 'y')] # TODO: is it better to set that via kernel cmd?
- 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)]
-
- # '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', '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 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 detect_compiler(fname):
+ gcc_version = None
+ clang_version = None
+ with _open(fname, 'rt', encoding='utf-8') as f:
+ gcc_version_pattern = re.compile("CONFIG_GCC_VERSION=[0-9]*")
+ clang_version_pattern = re.compile("CONFIG_CLANG_VERSION=[0-9]*")
+ for line in f.readlines():
+ if gcc_version_pattern.match(line):
+ gcc_version = line[19:-1]
+ if clang_version_pattern.match(line):
+ clang_version = line[21:-1]
+ if gcc_version is None or clang_version is None:
+ return None, 'no CONFIG_GCC_VERSION or CONFIG_CLANG_VERSION'
+ if gcc_version == '0' and clang_version != '0':
+ return 'CLANG ' + clang_version, 'OK'
+ if gcc_version != '0' and clang_version == '0':
+ return 'GCC ' + gcc_version, 'OK'
+ sys.exit(f'[!] ERROR: invalid GCC_VERSION and CLANG_VERSION: {gcc_version} {clang_version}')
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 o1 in checklist:
+ if o1.type != 'complex':
+ known_options.append(o1.name)
+ continue
+ for o2 in o1.opts:
+ if o2.type != 'complex':
+ if hasattr(o2, 'name'):
+ known_options.append(o2.name)
+ continue
+ for o3 in o2.opts:
+ assert(o3.type != 'complex'), \
+ f'unexpected ComplexOptCheck inside {o2.name}'
+ if hasattr(o3, 'name'):
+ known_options.append(o3.name)
+
for option, value in parsed_options.items():
if option not in known_options:
- print('[?] No rule for option {} ({})'.format(option, value))
+ print(f'[?] No check for option {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))
+ output = []
+ for opt in checklist:
+ output.append(opt.json_dump(with_results))
+ print(json.dumps(output))
return
# table header
if with_results:
sep_line_len += 30
print('=' * sep_line_len)
- print('{:^45}|{:^13}|{:^10}|{:^20}'.format('option name', 'desired val', 'decision', 'reason'), end='')
+ print(f'{"option name":^40}|{"type":^7}|{"desired val":^12}|{"decision":^10}|{"reason":^18}', end='')
if with_results:
- print('| {}'.format('check result'), end='')
+ print('| check result', end='')
print()
print('=' * sep_line_len)
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)
+ print(f'[+] Config check is finished: \'OK\' - {ok_count}{ok_suppressed} / \'FAIL\' - {fail_count}{fail_suppressed}')
-def parse_config_file(parsed_options, fname):
- with open(fname, 'r') as f:
+def parse_kconfig_file(parsed_options, fname):
+ with _open(fname, 'rt', encoding='utf-8') 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")
value = None
if opt_is_on.match(line):
- option, value = line[7:].split('=', 1)
+ option, value = line.split('=', 1)
+ if value == 'is not set':
+ sys.exit(f'[!] ERROR: bad enabled kconfig option "{line}"')
elif opt_is_off.match(line):
- option, value = line[9:].split(' ', 1)
+ option, value = line[2:].split(' ', 1)
if value != 'is not set':
- sys.exit('[!] ERROR: bad disabled config option "{}"'.format(line))
+ sys.exit(f'[!] ERROR: bad disabled kconfig option "{line}"')
if option in parsed_options:
- sys.exit('[!] ERROR: config option "{}" exists multiple times'.format(line))
+ sys.exit(f'[!] ERROR: kconfig option "{line}" exists multiple times')
if option:
parsed_options[option] = value
- return parsed_options
+
+def parse_cmdline_file(parsed_options, fname):
+ with open(fname, 'r', encoding='utf-8') as f:
+ line = f.readline()
+ opts = line.split()
+
+ line = f.readline()
+ if line:
+ sys.exit(f'[!] ERROR: more than one line in "{fname}"')
+
+ for opt in opts:
+ if '=' in opt:
+ name, value = opt.split('=', 1)
+ else:
+ name = opt
+ value = '' # '' is not None
+ value = normalize_cmdline_options(name, value)
+ parsed_options[name] = value
def main():
# Report modes:
# * verbose mode for
- # - reporting about unknown kernel options in the config
+ # - reporting about unknown kernel options in the kconfig
# - 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='Checks the hardening options in the Linux kernel config')
+ 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 hardening preferences for selected architecture')
+ help='print security hardening preferences for the selected architecture')
parser.add_argument('-c', '--config',
- help='check the kernel config file against these preferences')
+ help='check the kernel kconfig file against these preferences (also supports *.gz files)')
+ parser.add_argument('-l', '--cmdline',
+ help='check the kernel cmdline file against these preferences')
parser.add_argument('-m', '--mode', choices=report_modes,
help='choose the report mode')
args = parser.parse_args()
if args.mode:
mode = args.mode
if mode != 'json':
- print("[+] Special report mode: {}".format(mode))
+ print(f'[+] Special report mode: {mode}')
config_checklist = []
if args.config:
+ if args.print:
+ sys.exit('[!] ERROR: --config and --print can\'t be used together')
+
if mode != 'json':
- print('[+] Config file to check: {}'.format(args.config))
+ print(f'[+] Kconfig file to check: {args.config}')
+ if args.cmdline:
+ print(f'[+] Kernel cmdline file to check: {args.cmdline}')
arch, msg = detect_arch(args.config, supported_archs)
- if not arch:
- sys.exit('[!] ERROR: {}'.format(msg))
+ if arch is None:
+ sys.exit(f'[!] ERROR: {msg}')
if mode != 'json':
- print('[+] Detected architecture: {}'.format(arch))
+ print(f'[+] Detected architecture: {arch}')
- kernel_version, msg = detect_version(args.config)
- if not kernel_version:
- sys.exit('[!] ERROR: {}'.format(msg))
+ kernel_version, msg = detect_kernel_version(args.config)
+ if kernel_version is None:
+ sys.exit(f'[!] ERROR: {msg}')
if mode != 'json':
- print('[+] Detected kernel version: {}.{}'.format(kernel_version[0], kernel_version[1]))
+ print(f'[+] Detected kernel version: {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)
+ compiler, msg = detect_compiler(args.config)
+ if mode != 'json':
+ if compiler:
+ print(f'[+] Detected compiler: {compiler}')
+ else:
+ print(f'[-] Can\'t detect the compiler: {msg}')
+
+ # add relevant kconfig checks to the checklist
+ add_kconfig_checks(config_checklist, arch)
+
+ if args.cmdline:
+ # add relevant cmdline checks to the checklist
+ add_cmdline_checks(config_checklist, arch)
+
+ # populate the checklist with the parsed kconfig data
+ parsed_kconfig_options = OrderedDict()
+ parse_kconfig_file(parsed_kconfig_options, args.config)
+ populate_with_data(config_checklist, parsed_kconfig_options, 'kconfig')
+
+ # populate the checklist with the kernel version data
+ populate_with_data(config_checklist, kernel_version, 'version')
+
+ if args.cmdline:
+ # populate the checklist with the parsed cmdline data
+ parsed_cmdline_options = OrderedDict()
+ parse_cmdline_file(parsed_cmdline_options, args.cmdline)
+ populate_with_data(config_checklist, parsed_cmdline_options, 'cmdline')
+
+ # now everything is ready, perform the checks
+ perform_checks(config_checklist)
if mode == 'verbose':
- print_unknown_options(config_checklist, parsed_options)
+ # print the parsed options without the checks (for debugging)
+ all_parsed_options = parsed_kconfig_options # assignment does not copy
+ if args.cmdline:
+ all_parsed_options.update(parsed_cmdline_options)
+ print_unknown_options(config_checklist, all_parsed_options)
+
+ # finally print the results
print_checklist(mode, config_checklist, True)
sys.exit(0)
+ elif args.cmdline:
+ sys.exit('[!] ERROR: checking cmdline doesn\'t work without checking kconfig')
if args.print:
if mode in ('show_ok', 'show_fail'):
- sys.exit('[!] ERROR: please use "{}" mode for checking the kernel config'.format(mode))
+ sys.exit(f'[!] ERROR: wrong mode "{mode}" for --print')
arch = args.print
- construct_checklist(config_checklist, arch)
+ add_kconfig_checks(config_checklist, arch)
+ add_cmdline_checks(config_checklist, arch)
if mode != 'json':
- print('[+] Printing kernel hardening preferences for {}...'.format(arch))
+ print(f'[+] Printing kernel security hardening preferences for {arch}...')
print_checklist(mode, config_checklist, False)
sys.exit(0)
parser.print_help()
sys.exit(0)
-
-if __name__ == '__main__':
- main()