#!/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
-# 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
+"""
+This tool is for checking the security hardening options of the Linux kernel.
+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, add_sysctl_checks
+from .engine import populate_with_data, perform_checks, override_expected_value
-# pylint: disable=line-too-long,bad-whitespace,too-many-branches
-# pylint: disable=too-many-statements,global-statement
-
-# debug_mode enables:
-# - reporting about unknown kernel options in the config,
-# - verbose printing of ComplexOptChecks (OR, AND).
-debug_mode = False
-
-# json_mode is for printing results in JSON format
-json_mode = False
-
-supported_archs = ['X86_64', 'X86_32', 'ARM64', 'ARM']
-kernel_version = None
+def _open(file: str, *args, **kwargs):
+ open_method = open
+ if file.endswith(".gz"):
+ open_method = gzip.open
+ return open_method(file, *args, **kwargs)
-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, 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.result = None
-
- def check(self):
- if kernel_version[0] > self.ver_expected[0]:
- self.result = 'OK: version >= ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
- return True
- if kernel_version[0] < self.ver_expected[0]:
- self.result = 'FAIL: version < ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
- return False
- if kernel_version[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, 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, 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
- 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, with_results):
- if debug_mode:
- print(' {:87}'.format('<<< ' + self.__class__.__name__ + ' >>>'), end='')
- if with_results:
- print('| {}'.format(self.result), end='')
- for o in self.opts:
- print()
- o.table_print(with_results)
- else:
- o = self.opts[0]
- o.table_print(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 case:
- # OR(<X_is_hardened>, <X_is_disabled>)
- # OR(<X_is_hardened>, <X_is_hardened_old>)
-
- 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 i == 0 or not hasattr(opt, 'expected'):
- self.result = opt.result
- else:
- 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 case: AND(<suboption>, <main_option>)
- # Suboption is not checked if checking of the main_option is failed.
-
- 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:
- if hasattr(opt, 'expected'):
- self.result = 'FAIL: CONFIG_{} is needed'.format(opt.name)
- else:
- self.result = opt.result
- return False
-
- sys.exit('[!] ERROR: invalid AND check')
-
-
-def detect_arch(fname):
- with open(fname, 'r') as f:
- arch_pattern = re.compile("CONFIG_[a-zA-Z0-9_]*=y")
+def detect_arch(fname, archs):
+ with _open(fname, 'rt', encoding='utf-8') as f:
+ arch_pattern = re.compile("CONFIG_[a-zA-Z0-9_]+=y$")
arch = None
- if not json_mode:
- print('[+] Trying to detect architecture in "{}"...'.format(fname))
for line in f.readlines():
if arch_pattern.match(line):
option, _ = line[7:].split('=', 1)
- if option in supported_archs:
- if not arch:
+ if option in archs:
+ if arch is None:
arch = option
else:
- return None, 'more than one supported architecture is detected'
- if not arch:
- return None, 'failed to detect architecture'
+ return None, 'detected more than one microarchitecture'
+ if arch is None:
+ return None, 'failed to detect microarchitecture'
return arch, 'OK'
-def detect_version(fname):
- with open(fname, 'r') as f:
- ver_pattern = re.compile("# Linux/.* Kernel Configuration")
- if not json_mode:
- print('[+] Trying to detect kernel version in "{}"...'.format(fname))
+def detect_kernel_version(fname):
+ with _open(fname, 'rt', encoding='utf-8') as f:
+ ver_pattern = re.compile("# Linux/.+ Kernel Configuration$")
for line in f.readlines():
if ver_pattern.match(line):
line = line.strip()
- if not json_mode:
- print('[+] Found version line: "{}"'.format(line))
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 + '"'
+ 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(checklist, 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'
- checklist.append(OptCheck('self_protection', 'defconfig', 'BUG', 'y'))
- checklist.append(OR(OptCheck('self_protection', 'defconfig', 'STRICT_KERNEL_RWX', 'y'), \
- OptCheck('self_protection', 'defconfig', 'DEBUG_RODATA', 'y'))) # before v4.11
- checklist.append(OR(OptCheck('self_protection', 'defconfig', 'STACKPROTECTOR_STRONG', 'y'), \
- OptCheck('self_protection', 'defconfig', 'CC_STACKPROTECTOR_STRONG', 'y')))
- checklist.append(OptCheck('self_protection', 'defconfig', 'SLUB_DEBUG', 'y'))
- checklist.append(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
- checklist.append(OptCheck('self_protection', 'defconfig', 'GCC_PLUGINS', 'y'))
- checklist.append(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') # is needed for mitigating DMA attacks
- checklist.append(iommu_support_is_set)
- if arch in ('X86_64', 'X86_32'):
- checklist.append(OptCheck('self_protection', 'defconfig', 'MICROCODE', 'y')) # is needed for mitigating CPU bugs
- checklist.append(OptCheck('self_protection', 'defconfig', 'RETPOLINE', 'y'))
- checklist.append(OptCheck('self_protection', 'defconfig', 'X86_SMAP', 'y'))
- checklist.append(OR(OptCheck('self_protection', 'defconfig', 'X86_UMIP', 'y'), \
- OptCheck('self_protection', 'defconfig', 'X86_INTEL_UMIP', 'y')))
- checklist.append(OptCheck('self_protection', 'defconfig', 'SYN_COOKIES', 'y')) # another reason?
- if arch == 'X86_64':
- checklist.append(OptCheck('self_protection', 'defconfig', 'PAGE_TABLE_ISOLATION', 'y'))
- checklist.append(OptCheck('self_protection', 'defconfig', 'RANDOMIZE_MEMORY', 'y'))
- checklist.append(AND(OptCheck('self_protection', 'defconfig', 'INTEL_IOMMU', 'y'), \
- iommu_support_is_set))
- checklist.append(AND(OptCheck('self_protection', 'defconfig', 'AMD_IOMMU', 'y'), \
- iommu_support_is_set))
- if arch == 'ARM64':
- checklist.append(OptCheck('self_protection', 'defconfig', 'UNMAP_KERNEL_AT_EL0', 'y'))
- checklist.append(OptCheck('self_protection', 'defconfig', 'HARDEN_EL2_VECTORS', 'y'))
- checklist.append(OptCheck('self_protection', 'defconfig', 'RODATA_FULL_DEFAULT_ENABLED', 'y'))
- checklist.append(OptCheck('self_protection', 'defconfig', 'ARM64_PTR_AUTH', 'y'))
- if arch in ('X86_64', 'ARM64'):
- checklist.append(OptCheck('self_protection', 'defconfig', 'VMAP_STACK', 'y'))
- if arch in ('X86_64', 'ARM64', 'X86_32'):
- checklist.append(OptCheck('self_protection', 'defconfig', 'RANDOMIZE_BASE', 'y'))
- checklist.append(OptCheck('self_protection', 'defconfig', 'THREAD_INFO_IN_TASK', 'y'))
- if arch == 'ARM':
- checklist.append(OptCheck('self_protection', 'defconfig', 'CPU_SW_DOMAIN_PAN', 'y'))
- checklist.append(OptCheck('self_protection', 'defconfig', 'STACKPROTECTOR_PER_TASK', 'y'))
- if arch in ('ARM64', 'ARM'):
- checklist.append(OptCheck('self_protection', 'defconfig', 'HARDEN_BRANCH_PREDICTOR', 'y'))
-
- # 'self_protection', 'kspp'
- checklist.append(OptCheck('self_protection', 'kspp', 'BUG_ON_DATA_CORRUPTION', 'y'))
- checklist.append(OptCheck('self_protection', 'kspp', 'DEBUG_WX', 'y'))
- checklist.append(OptCheck('self_protection', 'kspp', 'SCHED_STACK_END_CHECK', 'y'))
- checklist.append(OptCheck('self_protection', 'kspp', 'SLAB_FREELIST_HARDENED', 'y'))
- checklist.append(OptCheck('self_protection', 'kspp', 'SLAB_FREELIST_RANDOM', 'y'))
- checklist.append(OptCheck('self_protection', 'kspp', 'SHUFFLE_PAGE_ALLOCATOR', 'y'))
- checklist.append(OptCheck('self_protection', 'kspp', 'FORTIFY_SOURCE', 'y'))
- randstruct_is_set = OptCheck('self_protection', 'kspp', 'GCC_PLUGIN_RANDSTRUCT', 'y')
- checklist.append(randstruct_is_set)
- checklist.append(OptCheck('self_protection', 'kspp', 'GCC_PLUGIN_LATENT_ENTROPY', 'y'))
- checklist.append(OptCheck('self_protection', 'kspp', 'DEBUG_LIST', 'y'))
- checklist.append(OptCheck('self_protection', 'kspp', 'DEBUG_SG', 'y'))
- checklist.append(OptCheck('self_protection', 'kspp', 'DEBUG_CREDENTIALS', 'y'))
- checklist.append(OptCheck('self_protection', 'kspp', 'DEBUG_NOTIFIERS', 'y'))
- hardened_usercopy_is_set = OptCheck('self_protection', 'kspp', 'HARDENED_USERCOPY', 'y')
- checklist.append(hardened_usercopy_is_set)
- checklist.append(AND(OptCheck('self_protection', 'kspp', 'HARDENED_USERCOPY_FALLBACK', 'is not set'), \
- hardened_usercopy_is_set))
- checklist.append(OR(OptCheck('self_protection', 'kspp', 'MODULE_SIG', 'y'), \
- modules_not_set))
- checklist.append(OR(OptCheck('self_protection', 'kspp', 'MODULE_SIG_ALL', 'y'), \
- modules_not_set))
- checklist.append(OR(OptCheck('self_protection', 'kspp', 'MODULE_SIG_SHA512', 'y'), \
- modules_not_set))
- checklist.append(OR(OptCheck('self_protection', 'kspp', 'MODULE_SIG_FORCE', 'y'), \
- modules_not_set)) # refers to LOCKDOWN
- checklist.append(OR(OptCheck('self_protection', 'kspp', 'INIT_STACK_ALL', 'y'), \
- OptCheck('self_protection', 'kspp', 'GCC_PLUGIN_STRUCTLEAK_BYREF_ALL', 'y')))
- checklist.append(OptCheck('self_protection', 'kspp', 'INIT_ON_ALLOC_DEFAULT_ON', 'y'))
- checklist.append(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')
- checklist.append(stackleak_is_set)
- checklist.append(AND(OptCheck('self_protection', 'clipos', 'STACKLEAK_METRICS', 'is not set'), \
- stackleak_is_set))
- checklist.append(AND(OptCheck('self_protection', 'clipos', 'STACKLEAK_RUNTIME_DISABLE', 'is not set'), \
- stackleak_is_set))
- if arch in ('X86_64', 'X86_32'):
- checklist.append(OptCheck('self_protection', 'kspp', 'DEFAULT_MMAP_MIN_ADDR', '65536'))
- if arch == 'X86_32':
- checklist.append(OptCheck('self_protection', 'kspp', 'PAGE_TABLE_ISOLATION', 'y'))
- checklist.append(OptCheck('self_protection', 'kspp', 'HIGHMEM64G', 'y'))
- checklist.append(OptCheck('self_protection', 'kspp', 'X86_PAE', 'y'))
- if arch == 'ARM64':
- checklist.append(OptCheck('self_protection', 'kspp', 'ARM64_SW_TTBR0_PAN', 'y'))
- if arch in ('ARM64', 'ARM'):
- checklist.append(OptCheck('self_protection', 'kspp', 'SYN_COOKIES', 'y')) # another reason?
- checklist.append(OptCheck('self_protection', 'kspp', 'DEFAULT_MMAP_MIN_ADDR', '32768'))
-
- # 'self_protection', 'clipos'
- checklist.append(OptCheck('self_protection', 'clipos', 'SECURITY_DMESG_RESTRICT', 'y'))
- checklist.append(OptCheck('self_protection', 'clipos', 'DEBUG_VIRTUAL', 'y'))
- checklist.append(OptCheck('self_protection', 'clipos', 'STATIC_USERMODEHELPER', 'y')) # needs userspace support
- checklist.append(OptCheck('self_protection', 'clipos', 'SLAB_MERGE_DEFAULT', 'is not set')) # slab_nomerge
- checklist.append(AND(OptCheck('self_protection', 'clipos', 'GCC_PLUGIN_RANDSTRUCT_PERFORMANCE', 'is not set'), \
- randstruct_is_set))
- checklist.append(OptCheck('self_protection', 'clipos', 'RANDOM_TRUST_BOOTLOADER', 'is not set'))
- checklist.append(OptCheck('self_protection', 'clipos', 'RANDOM_TRUST_CPU', 'is not set'))
- if arch in ('X86_64', 'X86_32'):
- checklist.append(AND(OptCheck('self_protection', 'clipos', 'INTEL_IOMMU_SVM', 'y'), \
- iommu_support_is_set))
- checklist.append(AND(OptCheck('self_protection', 'clipos', 'INTEL_IOMMU_DEFAULT_ON', 'y'), \
- iommu_support_is_set))
- if arch == 'X86_32':
- checklist.append(AND(OptCheck('self_protection', 'clipos', 'INTEL_IOMMU', 'y'), \
- iommu_support_is_set))
-
- # 'self_protection', 'my'
- checklist.append(OptCheck('self_protection', 'my', 'SLUB_DEBUG_ON', 'y'))
- checklist.append(OptCheck('self_protection', 'my', 'RESET_ATTACK_MITIGATION', 'y')) # needs userspace support (systemd)
- if arch == 'X86_64':
- checklist.append(AND(OptCheck('self_protection', 'my', 'AMD_IOMMU_V2', 'y'), \
- iommu_support_is_set))
-
- # 'security_policy'
- if arch in ('X86_64', 'ARM64', 'X86_32'):
- checklist.append(OptCheck('security_policy', 'defconfig', 'SECURITY', 'y')) # and choose your favourite LSM
- if arch == 'ARM':
- checklist.append(OptCheck('security_policy', 'kspp', 'SECURITY', 'y')) # and choose your favourite LSM
- checklist.append(OptCheck('security_policy', 'kspp', 'SECURITY_YAMA', 'y'))
- checklist.append(OR(OptCheck('security_policy', 'my', 'SECURITY_WRITABLE_HOOKS', 'is not set'), \
- OptCheck('security_policy', 'kspp', 'SECURITY_SELINUX_DISABLE', 'is not set')))
- checklist.append(OptCheck('security_policy', 'clipos', 'SECURITY_LOCKDOWN_LSM', 'y'))
- checklist.append(OptCheck('security_policy', 'clipos', 'SECURITY_LOCKDOWN_LSM_EARLY', 'y'))
- checklist.append(OptCheck('security_policy', 'clipos', 'LOCK_DOWN_KERNEL_FORCE_CONFIDENTIALITY', 'y'))
- loadpin_is_set = OptCheck('security_policy', 'my', 'SECURITY_LOADPIN', 'y') # needs userspace support
- checklist.append(loadpin_is_set)
- checklist.append(AND(OptCheck('security_policy', 'my', 'SECURITY_LOADPIN_ENFORCE', 'y'), \
- loadpin_is_set))
- checklist.append(OptCheck('security_policy', 'my', 'SECURITY_SAFESETID', 'y'))
-
- # 'cut_attack_surface', 'defconfig'
- checklist.append(OptCheck('cut_attack_surface', 'defconfig', 'SECCOMP', 'y'))
- checklist.append(OptCheck('cut_attack_surface', 'defconfig', 'SECCOMP_FILTER', 'y'))
- if arch in ('X86_64', 'ARM64', 'X86_32'):
- checklist.append(OR(OptCheck('cut_attack_surface', 'defconfig', 'STRICT_DEVMEM', 'y'), \
- devmem_not_set)) # refers to LOCKDOWN
-
- # 'cut_attack_surface', 'kspp'
- checklist.append(modules_not_set)
- checklist.append(devmem_not_set)
- checklist.append(OR(OptCheck('cut_attack_surface', 'kspp', 'IO_STRICT_DEVMEM', 'y'), \
- devmem_not_set)) # refers to LOCKDOWN
- if arch == 'ARM':
- checklist.append(OR(OptCheck('cut_attack_surface', 'kspp', 'STRICT_DEVMEM', 'y'), \
- devmem_not_set)) # refers to LOCKDOWN
- if arch == 'X86_64':
- checklist.append(OptCheck('cut_attack_surface', 'kspp', 'LEGACY_VSYSCALL_NONE', 'y')) # 'vsyscall=none'
- checklist.append(OptCheck('cut_attack_surface', 'kspp', 'ACPI_CUSTOM_METHOD', 'is not set')) # refers to LOCKDOWN
- checklist.append(OptCheck('cut_attack_surface', 'kspp', 'COMPAT_BRK', 'is not set'))
- checklist.append(OptCheck('cut_attack_surface', 'kspp', 'DEVKMEM', 'is not set')) # refers to LOCKDOWN
- checklist.append(OptCheck('cut_attack_surface', 'kspp', 'COMPAT_VDSO', 'is not set'))
- checklist.append(OptCheck('cut_attack_surface', 'kspp', 'BINFMT_MISC', 'is not set'))
- checklist.append(OptCheck('cut_attack_surface', 'kspp', 'INET_DIAG', 'is not set'))
- checklist.append(OptCheck('cut_attack_surface', 'kspp', 'KEXEC', 'is not set')) # refers to LOCKDOWN
- checklist.append(OptCheck('cut_attack_surface', 'kspp', 'PROC_KCORE', 'is not set')) # refers to LOCKDOWN
- checklist.append(OptCheck('cut_attack_surface', 'kspp', 'LEGACY_PTYS', 'is not set'))
- checklist.append(OptCheck('cut_attack_surface', 'kspp', 'HIBERNATION', 'is not set')) # refers to LOCKDOWN
- checklist.append(OptCheck('cut_attack_surface', 'kspp', 'IA32_EMULATION', 'is not set'))
- checklist.append(OptCheck('cut_attack_surface', 'kspp', 'X86_X32', 'is not set'))
- checklist.append(OptCheck('cut_attack_surface', 'kspp', 'MODIFY_LDT_SYSCALL', 'is not set'))
- checklist.append(OptCheck('cut_attack_surface', 'kspp', 'OABI_COMPAT', 'is not set'))
-
- # 'cut_attack_surface', 'grsecurity'
- checklist.append(OptCheck('cut_attack_surface', 'grsecurity', 'X86_PTDUMP', 'is not set'))
- checklist.append(OptCheck('cut_attack_surface', 'grsecurity', 'ZSMALLOC_STAT', 'is not set'))
- checklist.append(OptCheck('cut_attack_surface', 'grsecurity', 'PAGE_OWNER', 'is not set'))
- checklist.append(OptCheck('cut_attack_surface', 'grsecurity', 'DEBUG_KMEMLEAK', 'is not set'))
- checklist.append(OptCheck('cut_attack_surface', 'grsecurity', 'BINFMT_AOUT', 'is not set'))
- checklist.append(OptCheck('cut_attack_surface', 'grsecurity', 'KPROBES', 'is not set')) # refers to LOCKDOWN
- checklist.append(OptCheck('cut_attack_surface', 'grsecurity', 'UPROBES', 'is not set'))
- checklist.append(OptCheck('cut_attack_surface', 'grsecurity', 'GENERIC_TRACER', 'is not set')) # refers to LOCKDOWN
- checklist.append(OptCheck('cut_attack_surface', 'grsecurity', 'PROC_VMCORE', 'is not set'))
- checklist.append(OptCheck('cut_attack_surface', 'grsecurity', 'PROC_PAGE_MONITOR', 'is not set'))
- checklist.append(OptCheck('cut_attack_surface', 'grsecurity', 'USELIB', 'is not set'))
- checklist.append(OptCheck('cut_attack_surface', 'grsecurity', 'CHECKPOINT_RESTORE', 'is not set'))
- checklist.append(OptCheck('cut_attack_surface', 'grsecurity', 'USERFAULTFD', 'is not set'))
- checklist.append(OptCheck('cut_attack_surface', 'grsecurity', 'HWPOISON_INJECT', 'is not set'))
- checklist.append(OptCheck('cut_attack_surface', 'grsecurity', 'MEM_SOFT_DIRTY', 'is not set'))
- checklist.append(OptCheck('cut_attack_surface', 'grsecurity', 'DEVPORT', 'is not set')) # refers to LOCKDOWN
- checklist.append(OptCheck('cut_attack_surface', 'grsecurity', 'DEBUG_FS', 'is not set')) # refers to LOCKDOWN
- checklist.append(OptCheck('cut_attack_surface', 'grsecurity', 'NOTIFIER_ERROR_INJECTION','is not set'))
-
- # 'cut_attack_surface', 'maintainer'
- checklist.append(OptCheck('cut_attack_surface', 'maintainer', 'DRM_LEGACY', 'is not set'))
- checklist.append(OptCheck('cut_attack_surface', 'maintainer', 'FB', 'is not set'))
- checklist.append(OptCheck('cut_attack_surface', 'maintainer', 'VT', 'is not set'))
-
- # 'cut_attack_surface', 'lockdown'
- checklist.append(OptCheck('cut_attack_surface', 'lockdown', 'ACPI_TABLE_UPGRADE', 'is not set')) # refers to LOCKDOWN
- checklist.append(OptCheck('cut_attack_surface', 'lockdown', 'X86_IOPL_IOPERM', 'is not set')) # refers to LOCKDOWN
- checklist.append(OptCheck('cut_attack_surface', 'lockdown', 'EFI_TEST', 'is not set')) # refers to LOCKDOWN
- checklist.append(OptCheck('cut_attack_surface', 'lockdown', 'BPF_SYSCALL', 'is not set')) # refers to LOCKDOWN
- checklist.append(OptCheck('cut_attack_surface', 'lockdown', 'MMIOTRACE_TEST', 'is not set')) # refers to LOCKDOWN
-
- # 'cut_attack_surface', 'clipos'
- if arch in ('X86_64', 'X86_32'):
- checklist.append(OptCheck('cut_attack_surface', 'clipos', 'X86_INTEL_TSX_MODE_OFF', 'y')) # tsx=off
- checklist.append(OptCheck('cut_attack_surface', 'clipos', 'STAGING', 'is not set'))
- checklist.append(OptCheck('cut_attack_surface', 'clipos', 'KSM', 'is not set')) # to prevent FLUSH+RELOAD attack
-# checklist.append(OptCheck('cut_attack_surface', 'clipos', 'IKCONFIG', 'is not set')) # no, this info is needed for this check :)
- checklist.append(OptCheck('cut_attack_surface', 'clipos', 'KALLSYMS', 'is not set'))
- checklist.append(OptCheck('cut_attack_surface', 'clipos', 'X86_VSYSCALL_EMULATION', 'is not set'))
- checklist.append(OptCheck('cut_attack_surface', 'clipos', 'MAGIC_SYSRQ', 'is not set'))
- checklist.append(OptCheck('cut_attack_surface', 'clipos', 'KEXEC_FILE', 'is not set')) # refers to LOCKDOWN (permissive)
- checklist.append(OptCheck('cut_attack_surface', 'clipos', 'USER_NS', 'is not set')) # user.max_user_namespaces=0
- checklist.append(OptCheck('cut_attack_surface', 'clipos', 'X86_MSR', 'is not set')) # refers to LOCKDOWN
- checklist.append(OptCheck('cut_attack_surface', 'clipos', 'X86_CPUID', 'is not set'))
- checklist.append(AND(OptCheck('cut_attack_surface', 'clipos', 'LDISC_AUTOLOAD', 'is not set'), \
- PresenceCheck('LDISC_AUTOLOAD')))
-
- # 'cut_attack_surface', 'grapheneos'
- checklist.append(OptCheck('cut_attack_surface', 'grapheneos', 'AIO', 'is not set'))
-
- # 'cut_attack_surface', 'my'
- checklist.append(OptCheck('cut_attack_surface', 'my', 'MMIOTRACE', 'is not set')) # refers to LOCKDOWN (permissive)
- checklist.append(OptCheck('cut_attack_surface', 'my', 'LIVEPATCH', 'is not set'))
- checklist.append(OptCheck('cut_attack_surface', 'my', 'IP_DCCP', 'is not set'))
- checklist.append(OptCheck('cut_attack_surface', 'my', 'IP_SCTP', 'is not set'))
- checklist.append(OptCheck('cut_attack_surface', 'my', 'FTRACE', 'is not set')) # refers to LOCKDOWN
- checklist.append(OptCheck('cut_attack_surface', 'my', 'BPF_JIT', 'is not set'))
- checklist.append(OptCheck('cut_attack_surface', 'my', 'VIDEO_VIVID', 'is not set'))
- checklist.append(OptCheck('cut_attack_surface', 'my', 'INPUT_EVBUG', 'is not set')) # Can be used as a keylogger
-
- # 'userspace_hardening'
- checklist.append(OptCheck('userspace_hardening', 'defconfig', 'INTEGRITY', 'y'))
- if arch in ('ARM', 'X86_32'):
- checklist.append(OptCheck('userspace_hardening', 'defconfig', 'VMSPLIT_3G', 'y'))
- if arch in ('X86_64', 'ARM64'):
- checklist.append(OptCheck('userspace_hardening', 'clipos', 'ARCH_MMAP_RND_BITS', '32'))
- if arch in ('X86_32', 'ARM'):
- checklist.append(OptCheck('userspace_hardening', 'my', 'ARCH_MMAP_RND_BITS', '16'))
-
-# checklist.append(OptCheck('feature_test', 'my', 'LKDTM', 'm')) # only for debugging!
-
-
-def print_checklist(checklist, with_results):
- if json_mode:
- 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))
+def detect_compiler(fname):
+ gcc_version = None
+ clang_version = None
+ with _open(fname, 'rt', encoding='utf-8') as f:
+ for line in f.readlines():
+ if line.startswith('CONFIG_GCC_VERSION='):
+ gcc_version = line[19:-1]
+ if line.startswith('CONFIG_CLANG_VERSION='):
+ 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 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(f'[?] No check for option {option} ({value})')
+
+
+def print_checklist(mode, checklist, with_results):
+ if mode == 'json':
+ 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)
# table contents
for opt in checklist:
- opt.table_print(with_results)
+ 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 debug_mode:
+ 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)'
+ print(f'[+] Config check is finished: \'OK\' - {ok_count}{ok_suppressed} / \'FAIL\' - {fail_count}{fail_suppressed}')
+
+
+def parse_kconfig_file(mode, parsed_options, fname):
+ with _open(fname, 'rt', encoding='utf-8') as f:
+ opt_is_on = re.compile("CONFIG_[a-zA-Z0-9_]+=.+$")
+ opt_is_off = re.compile("# CONFIG_[a-zA-Z0-9_]+ is not set$")
-def perform_checks(checklist, parsed_options):
- for opt in checklist:
- if hasattr(opt, 'opts'):
- # prepare ComplexOptCheck
- for o in opt.opts:
- if hasattr(o, 'state'):
- o.state = parsed_options.get(o.name, None)
- else:
- # prepare simple check
- 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 check_config_file(checklist, fname, arch):
- with open(fname, 'r') as f:
- parsed_options = OrderedDict()
- 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")
-
- if not json_mode:
- print('[+] Checking "{}" against {} hardening preferences...'.format(fname, arch))
for line in f.readlines():
line = line.strip()
option = None
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)
- if value != 'is not set':
- sys.exit('[!] ERROR: bad disabled config option "{}"'.format(line))
+ option, value = line[2:].split(' ', 1)
+ assert(value == 'is not set'), \
+ f'unexpected value of disabled Kconfig option "{line}"'
+ elif line != '' and not line.startswith('#') and mode != 'json':
+ print(f'[!] WARNING: strange line in Kconfig file: "{line}"')
if option in parsed_options:
- sys.exit('[!] ERROR: config option "{}" exists multiple times'.format(line))
+ sys.exit(f'[!] ERROR: Kconfig option "{line}" is found multiple times')
- if option is not None:
+ if option:
parsed_options[option] = value
- perform_checks(checklist, parsed_options)
- if debug_mode:
- 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('DEBUG: dunno about option {} ({})'.format(option, value))
+def parse_cmdline_file(mode, parsed_options, fname):
+ with open(fname, 'r', encoding='utf-8') as f:
+ line = f.readline()
+ opts = line.split()
- print_checklist(checklist, True)
+ line = f.readline()
+ if line:
+ sys.exit(f'[!] ERROR: more than one line in "{fname}"')
-def main():
- global debug_mode
- global json_mode
- global kernel_version
+ for opt in opts:
+ if '=' in opt:
+ name, value = opt.split('=', 1)
+ else:
+ name = opt
+ value = '' # '' is not None
+ if name in parsed_options and mode != 'json':
+ print(f'[!] WARNING: cmdline option "{name}" is found multiple times')
+ value = normalize_cmdline_options(name, value)
+ parsed_options[name] = value
- config_checklist = []
+def parse_sysctl_file(mode, parsed_options, fname):
+ with open(fname, 'r', encoding='utf-8') as f:
+ sysctl_pattern = re.compile("[a-zA-Z0-9\._-]+ =.*$")
+ for line in f.readlines():
+ line = line.strip()
+ if not sysctl_pattern.match(line):
+ sys.exit(f'[!] ERROR: unexpected line in sysctl file: {line}')
+ option, value = line.split('=', 1)
+ option = option.strip()
+ value = value.strip()
+ # sysctl options may be found multiple times, let's save the last value:
+ parsed_options[option] = value
+
+ # let's check the presence of some ancient sysctl option
+ # to ensure that we are parsing the output of `sudo sysctl -a > file`
+ if 'kernel.printk' not in parsed_options:
+ sys.exit(f'[!] ERROR: {fname} doesn\'t look like a sysctl output file, please try `sudo sysctl -a > {fname}`')
+
+ # let's check the presence of a sysctl option available for root
+ if 'net.core.bpf_jit_harden' not in parsed_options and mode != 'json':
+ print(f'[!] WARNING: sysctl option "net.core.bpf_jit_harden" available for root is not found in {fname}, please try `sudo sysctl -a > {fname}`')
+
+
+def main():
+ # Report modes:
+ # * verbose mode for
+ # - 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')
- parser.add_argument('-p', '--print', choices=supported_archs,
- help='print hardening preferences for selected architecture')
- parser.add_argument('-c', '--config',
- help='check the config_file against these preferences')
- parser.add_argument('--debug', action='store_true',
- help='enable verbose debug mode')
- parser.add_argument('--json', action='store_true',
- help='print results in JSON format')
+ 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('-m', '--mode', choices=report_modes,
+ help='choose the report mode')
+ parser.add_argument('-c', '--config',
+ help='check the security hardening options in the kernel Kconfig file (also supports *.gz files)')
+ parser.add_argument('-l', '--cmdline',
+ help='check the security hardening options in the kernel cmdline file (contents of /proc/cmdline)')
+ parser.add_argument('-s', '--sysctl',
+ help='check the security hardening options in the sysctl output file (`sudo sysctl -a > file`)')
+ parser.add_argument('-p', '--print', choices=supported_archs,
+ help='print the security hardening recommendations for the selected microarchitecture')
+ parser.add_argument('-g', '--generate', choices=supported_archs,
+ help='generate a Kconfig fragment with the security hardening options for the selected microarchitecture')
args = parser.parse_args()
- if args.debug:
- debug_mode = True
- print('[!] WARNING: debug mode is enabled')
- if args.json:
- json_mode = True
- if debug_mode and json_mode:
- sys.exit('[!] ERROR: options --debug and --json cannot be used simultaneously')
+ mode = None
+ if args.mode:
+ mode = args.mode
+ if mode != 'json':
+ print(f'[+] Special report mode: {mode}')
+
+ config_checklist = []
if args.config:
- arch, msg = detect_arch(args.config)
- if not arch:
- sys.exit('[!] ERROR: {}'.format(msg))
- elif not json_mode:
- print('[+] Detected architecture: {}'.format(arch))
-
- kernel_version, msg = detect_version(args.config)
- if not kernel_version:
- sys.exit('[!] ERROR: {}'.format(msg))
- elif not json_mode:
- print('[+] Detected kernel version: {}.{}'.format(kernel_version[0], kernel_version[1]))
-
- construct_checklist(config_checklist, arch)
- check_config_file(config_checklist, args.config, arch)
- error_count = len(list(filter(lambda opt: opt.result.startswith('FAIL'), config_checklist)))
- ok_count = len(list(filter(lambda opt: opt.result.startswith('OK'), config_checklist)))
- if not debug_mode and not json_mode:
- print('[+] config check is finished: \'OK\' - {} / \'FAIL\' - {}'.format(ok_count, error_count))
+ if args.print:
+ sys.exit('[!] ERROR: --config and --print can\'t be used together')
+
+ if args.generate:
+ sys.exit('[!] ERROR: --config and --generate can\'t be used together')
+
+ if mode != 'json':
+ print(f'[+] Kconfig file to check: {args.config}')
+ if args.cmdline:
+ print(f'[+] Kernel cmdline file to check: {args.cmdline}')
+ if args.sysctl:
+ print(f'[+] Sysctl output file to check: {args.sysctl}')
+
+ arch, msg = detect_arch(args.config, supported_archs)
+ if arch is None:
+ sys.exit(f'[!] ERROR: {msg}')
+ if mode != 'json':
+ print(f'[+] Detected microarchitecture: {arch}')
+
+ kernel_version, msg = detect_kernel_version(args.config)
+ if kernel_version is None:
+ sys.exit(f'[!] ERROR: {msg}')
+ if mode != 'json':
+ print(f'[+] Detected kernel version: {kernel_version[0]}.{kernel_version[1]}')
+
+ 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)
+
+ if args.sysctl:
+ # add relevant sysctl checks to the checklist
+ add_sysctl_checks(config_checklist, arch)
+
+ # populate the checklist with the parsed Kconfig data
+ parsed_kconfig_options = OrderedDict()
+ parse_kconfig_file(mode, 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(mode, parsed_cmdline_options, args.cmdline)
+ populate_with_data(config_checklist, parsed_cmdline_options, 'cmdline')
+
+ if args.sysctl:
+ # populate the checklist with the parsed sysctl data
+ parsed_sysctl_options = OrderedDict()
+ parse_sysctl_file(mode, parsed_sysctl_options, args.sysctl)
+ populate_with_data(config_checklist, parsed_sysctl_options, 'sysctl')
+
+ # hackish refinement of the CONFIG_ARCH_MMAP_RND_BITS check
+ mmap_rnd_bits_max = parsed_kconfig_options.get('CONFIG_ARCH_MMAP_RND_BITS_MAX', None)
+ if mmap_rnd_bits_max:
+ override_expected_value(config_checklist, 'CONFIG_ARCH_MMAP_RND_BITS', mmap_rnd_bits_max)
+
+ # now everything is ready, perform the checks
+ perform_checks(config_checklist)
+
+ if mode == 'verbose':
+ # 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)
+ if args.sysctl:
+ all_parsed_options.update(parsed_sysctl_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 depends on checking Kconfig')
+ elif args.sysctl:
+ # TODO: sysctl check should also work separately
+ sys.exit('[!] ERROR: checking sysctl depends on checking Kconfig')
if args.print:
+ assert(args.config is None and args.cmdline is None and args.sysctl is None), 'unexpected args'
+ if mode and mode not in ('verbose', 'json'):
+ sys.exit(f'[!] ERROR: wrong mode "{mode}" for --print')
arch = args.print
- construct_checklist(config_checklist, arch)
- if not json_mode:
- print('[+] Printing kernel hardening preferences for {}...'.format(arch))
- print_checklist(config_checklist, False)
+ add_kconfig_checks(config_checklist, arch)
+ add_cmdline_checks(config_checklist, arch)
+ add_sysctl_checks(config_checklist, arch)
+ if mode != 'json':
+ print(f'[+] Printing kernel security hardening options for {arch}...')
+ print_checklist(mode, config_checklist, False)
+ sys.exit(0)
+
+ if args.generate:
+ assert(args.config is None and args.cmdline is None and args.sysctl is None), 'unexpected args'
+ if mode:
+ sys.exit(f'[!] ERROR: wrong mode "{mode}" for --generate')
+ arch = args.generate
+ add_kconfig_checks(config_checklist, arch)
+ print(f'CONFIG_{arch}=y') # the Kconfig fragment should describe the microarchitecture
+ for opt in config_checklist:
+ if opt.name == 'CONFIG_ARCH_MMAP_RND_BITS':
+ continue # don't add CONFIG_ARCH_MMAP_RND_BITS because its value needs refinement
+ if opt.expected == 'is not set':
+ print(f'# {opt.name} is not set')
+ else:
+ print(f'{opt.name}={opt.expected}')
sys.exit(0)
parser.print_help()
sys.exit(0)
-
-if __name__ == '__main__':
- main()
projects / kconfig-hardened-check.git / blobdiff