#!/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.
+# 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>
# pti=on
# spec_store_bypass_disable=on
# l1tf=full,force
+# l1d_flush=on (a part of the l1tf option)
# mds=full,nosmt
# tsx=off
-# l1d_flush=on
# ARM64:
# kpti=on
# ssbd=force-on
import json
from .__about__ import __version__
+TYPES_OF_CHECKS = ('kconfig', 'version')
class OptCheck:
def __init__(self, reason, decision, name, expected):
else:
self.result = 'FAIL: "' + self.state + '"'
- if self.result.startswith('OK'):
- return True
- return False
+ def table_print(self, _mode, with_results):
+ print('{:<40}|{:^7}|{:^12}|{:^10}|{:^18}'.format(self.name, self.type, self.expected, self.decision, self.reason), end='')
+ if with_results:
+ print('| {}'.format(self.result), end='')
class KconfigCheck(OptCheck):
+ def __init__(self, *args, **kwargs):
+ super().__init__(*args, **kwargs)
+ self.name = 'CONFIG_' + self.name
+
@property
def type(self):
- return "kconfig"
+ return 'kconfig'
- def table_print(self, _mode, with_results):
- print('CONFIG_{:<33}|{:^7}|{:^12}|{:^10}|{:^18}'.format(self.name, self.type, self.expected, self.decision, self.reason), end='')
+ def json_dump(self, with_results):
+ dump = [self.name, self.type, self.expected, self.decision, self.reason]
if with_results:
- print('| {}'.format(self.result), end='')
+ dump.append(self.result)
+ return dump
-class VerCheck:
+class VersionCheck:
def __init__(self, ver_expected):
self.ver_expected = ver_expected
self.ver = ()
self.result = None
+ @property
+ def type(self):
+ return 'version'
+
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
+ return
if self.ver[0] < self.ver_expected[0]:
self.result = 'FAIL: version < ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
- return False
+ return
if self.ver[1] >= self.ver_expected[1]:
self.result = 'OK: version >= ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
- return True
+ return
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])
class PresenceCheck:
- def __init__(self, name):
- self.name = name
+ def __init__(self, name, type):
+ self.type = type
+ if self.type == 'kconfig':
+ self.name = 'CONFIG_' + name
+ else:
+ sys.exit('[!] ERROR: unsupported type "{}" for {}'.format(type, self.__class__.__name__))
self.state = None
self.result = None
def check(self):
if self.state is None:
self.result = 'FAIL: not present'
- return False
+ return
self.result = 'OK: is present'
- return True
def table_print(self, _mode, with_results):
- print('CONFIG_{:<84}'.format(self.name + ' is present'), end='')
+ print('{:<91}'.format(self.name + ' is present'), end='')
if with_results:
print('| {}'.format(self.result), end='')
self.opts = opts
if not self.opts:
sys.exit('[!] ERROR: empty {} check'.format(self.__class__.__name__))
+ if len(self.opts) == 1:
+ sys.exit('[!] ERROR: useless {} check'.format(self.__class__.__name__))
if not isinstance(opts[0], KconfigCheck):
sys.exit('[!] ERROR: invalid {} check: {}'.format(self.__class__.__name__, opts))
self.result = None
@property
def type(self):
- return self.opts[0].type
+ return 'complex'
@property
def expected(self):
if with_results:
print('| {}'.format(self.result), end='')
+ def json_dump(self, with_results):
+ dump = self.opts[0].json_dump(False)
+ if with_results:
+ dump.append(self.result)
+ return dump
+
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
+ opt.check()
+ if opt.result.startswith('OK'):
+ if opt.result == 'OK' and i != 0:
+ # Simple OK is not enough for additional checks, add more info:
+ self.result = 'OK: {} "{}"'.format(opt.name, opt.expected)
else:
- # Simple OK is not enough for additional checks.
- self.result = 'OK: CONFIG_{} "{}"'.format(opt.name, opt.expected)
- return True
+ self.result = opt.result
+ return
self.result = self.opts[0].result
- return False
class AND(ComplexOptCheck):
# 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()
+ opt.check()
if i == 0:
self.result = opt.result
- return ret
- if not ret:
+ return
+ if not opt.result.startswith('OK'):
# 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)
+ self.result = 'FAIL: {} not "{}"'.format(opt.name, opt.expected)
elif opt.result == 'FAIL: not present':
- self.result = 'FAIL: CONFIG_{} not present'.format(opt.name)
+ self.result = 'FAIL: {} not present'.format(opt.name)
else:
# This FAIL message is self-explaining.
self.result = opt.result
- return False
-
+ return
sys.exit('[!] ERROR: invalid AND check')
modules_not_set = KconfigCheck('cut_attack_surface', 'kspp', 'MODULES', 'is not set')
devmem_not_set = KconfigCheck('cut_attack_surface', 'kspp', 'DEVMEM', 'is not set') # refers to LOCKDOWN
+ bpf_syscall_not_set = KconfigCheck('cut_attack_surface', 'lockdown', 'BPF_SYSCALL', 'is not set') # refers to LOCKDOWN
+ efi_not_set = KconfigCheck('cut_attack_surface', 'my', 'EFI', 'is not set')
# 'self_protection', 'defconfig'
l += [KconfigCheck('self_protection', 'defconfig', 'BUG', 'y')]
KconfigCheck('self_protection', 'defconfig', 'DEBUG_SET_MODULE_RONX', 'y'),
modules_not_set)] # DEBUG_SET_MODULE_RONX was before v4.11
l += [OR(KconfigCheck('self_protection', 'defconfig', 'REFCOUNT_FULL', 'y'),
- VerCheck((5, 5)))] # REFCOUNT_FULL is enabled by default since v5.5
+ VersionCheck((5, 5)))] # REFCOUNT_FULL is enabled by default since v5.5
+ l += [KconfigCheck('self_protection', 'defconfig', 'THREAD_INFO_IN_TASK', 'y')]
iommu_support_is_set = KconfigCheck('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 += [KconfigCheck('self_protection', 'defconfig', 'RANDOMIZE_BASE', 'y')]
- l += [KconfigCheck('self_protection', 'defconfig', 'THREAD_INFO_IN_TASK', 'y')]
if arch in ('X86_64', 'ARM64'):
l += [KconfigCheck('self_protection', 'defconfig', 'VMAP_STACK', 'y')]
if arch in ('X86_64', 'X86_32'):
l += [KconfigCheck('self_protection', 'defconfig', 'UNMAP_KERNEL_AT_EL0', 'y')]
l += [OR(KconfigCheck('self_protection', 'defconfig', 'HARDEN_EL2_VECTORS', 'y'),
AND(KconfigCheck('self_protection', 'defconfig', 'RANDOMIZE_BASE', 'y'),
- VerCheck((5, 9))))] # HARDEN_EL2_VECTORS was included in RANDOMIZE_BASE in v5.9
+ VersionCheck((5, 9))))] # HARDEN_EL2_VECTORS was included in RANDOMIZE_BASE in v5.9
l += [KconfigCheck('self_protection', 'defconfig', 'RODATA_FULL_DEFAULT_ENABLED', 'y')]
l += [KconfigCheck('self_protection', 'defconfig', 'ARM64_PTR_AUTH_KERNEL', 'y')]
l += [KconfigCheck('self_protection', 'defconfig', 'ARM64_BTI_KERNEL', 'y')]
l += [OR(KconfigCheck('self_protection', 'defconfig', 'HARDEN_BRANCH_PREDICTOR', 'y'),
- VerCheck((5, 10)))] # HARDEN_BRANCH_PREDICTOR is enabled by default since v5.10
+ VersionCheck((5, 10)))] # HARDEN_BRANCH_PREDICTOR is enabled by default since v5.10
+ l += [KconfigCheck('self_protection', 'defconfig', 'MITIGATE_SPECTRE_BRANCH_HISTORY', 'y')]
l += [KconfigCheck('self_protection', 'defconfig', 'ARM64_MTE', 'y')]
if arch == 'ARM':
l += [KconfigCheck('self_protection', 'defconfig', 'CPU_SW_DOMAIN_PAN', 'y')]
l += [KconfigCheck('self_protection', 'defconfig', 'HARDEN_BRANCH_PREDICTOR', 'y')]
+ l += [KconfigCheck('self_protection', 'defconfig', 'HARDEN_BRANCH_HISTORY', 'y')]
# 'self_protection', 'kspp'
l += [KconfigCheck('self_protection', 'kspp', 'SECURITY_DMESG_RESTRICT', 'y')]
l += [KconfigCheck('self_protection', 'kspp', 'DEBUG_NOTIFIERS', 'y')]
l += [KconfigCheck('self_protection', 'kspp', 'INIT_ON_ALLOC_DEFAULT_ON', 'y')]
l += [KconfigCheck('self_protection', 'kspp', 'GCC_PLUGIN_LATENT_ENTROPY', 'y')]
+ l += [KconfigCheck('self_protection', 'kspp', 'KFENCE', 'y')]
+ l += [KconfigCheck('self_protection', 'kspp', 'WERROR', 'y')]
randstruct_is_set = KconfigCheck('self_protection', 'kspp', 'GCC_PLUGIN_RANDSTRUCT', 'y')
l += [randstruct_is_set]
hardened_usercopy_is_set = KconfigCheck('self_protection', 'kspp', 'HARDENED_USERCOPY', 'y')
# 'self_protection', 'maintainer'
ubsan_bounds_is_set = KconfigCheck('self_protection', 'maintainer', 'UBSAN_BOUNDS', 'y') # only array index bounds checking
l += [ubsan_bounds_is_set] # recommended by Kees Cook in /issues/53
- l += [AND(KconfigCheck('self_protection', 'maintainer', 'UBSAN_SANITIZE_ALL', 'y'),
- ubsan_bounds_is_set)] # recommended by Kees Cook in /issues/53
+ if arch in ('X86_64', 'ARM64', 'X86_32'): # ARCH_HAS_UBSAN_SANITIZE_ALL is not enabled for ARM
+ l += [AND(KconfigCheck('self_protection', 'maintainer', 'UBSAN_SANITIZE_ALL', 'y'),
+ ubsan_bounds_is_set)] # recommended by Kees Cook in /issues/53
l += [AND(KconfigCheck('self_protection', 'maintainer', 'UBSAN_TRAP', 'y'),
ubsan_bounds_is_set)] # recommended by Kees Cook in /issues/53
# 'self_protection', 'clipos'
l += [KconfigCheck('self_protection', 'clipos', 'DEBUG_VIRTUAL', 'y')]
l += [KconfigCheck('self_protection', 'clipos', 'STATIC_USERMODEHELPER', 'y')] # needs userspace support
- l += [KconfigCheck('self_protection', 'clipos', 'EFI_DISABLE_PCI_DMA', 'y')]
+ l += [OR(KconfigCheck('self_protection', 'clipos', 'EFI_DISABLE_PCI_DMA', 'y'),
+ efi_not_set)]
l += [KconfigCheck('self_protection', 'clipos', 'SLAB_MERGE_DEFAULT', 'is not set')] # slab_nomerge
l += [KconfigCheck('self_protection', 'clipos', 'RANDOM_TRUST_BOOTLOADER', 'is not set')]
l += [KconfigCheck('self_protection', 'clipos', 'RANDOM_TRUST_CPU', 'is not set')]
iommu_support_is_set)]
# 'self_protection', 'my'
- l += [KconfigCheck('self_protection', 'my', 'RESET_ATTACK_MITIGATION', 'y')] # needs userspace support (systemd)
+ l += [OR(KconfigCheck('self_protection', 'my', 'RESET_ATTACK_MITIGATION', 'y'),
+ efi_not_set)] # needs userspace support (systemd)
if arch == 'X86_64':
+ l += [KconfigCheck('self_protection', 'my', 'SLS', 'y')] # vs CVE-2021-26341 in Straight-Line-Speculation
l += [AND(KconfigCheck('self_protection', 'my', 'AMD_IOMMU_V2', 'y'),
iommu_support_is_set)]
if arch == 'ARM64':
loadpin_is_set)]
# 'cut_attack_surface', 'defconfig'
+ l += [OR(KconfigCheck('cut_attack_surface', 'defconfig', 'BPF_UNPRIV_DEFAULT_OFF', 'y'),
+ bpf_syscall_not_set)] # see unprivileged_bpf_disabled
l += [KconfigCheck('cut_attack_surface', 'defconfig', 'SECCOMP', 'y')]
l += [KconfigCheck('cut_attack_surface', 'defconfig', 'SECCOMP_FILTER', 'y')]
if arch in ('X86_64', 'ARM64', 'X86_32'):
l += [KconfigCheck('cut_attack_surface', 'clipos', 'ACPI_TABLE_UPGRADE', 'is not set')] # refers to LOCKDOWN
l += [KconfigCheck('cut_attack_surface', 'clipos', 'EFI_CUSTOM_SSDT_OVERLAYS', 'is not set')]
l += [AND(KconfigCheck('cut_attack_surface', 'clipos', 'LDISC_AUTOLOAD', 'is not set'),
- PresenceCheck('LDISC_AUTOLOAD'))]
+ PresenceCheck('LDISC_AUTOLOAD', 'kconfig'))]
if arch in ('X86_64', 'X86_32'):
l += [KconfigCheck('cut_attack_surface', 'clipos', 'X86_INTEL_TSX_MODE_OFF', 'y')] # tsx=off
# 'cut_attack_surface', 'lockdown'
+ l += [bpf_syscall_not_set] # refers to LOCKDOWN
l += [KconfigCheck('cut_attack_surface', 'lockdown', 'EFI_TEST', 'is not set')] # refers to LOCKDOWN
- l += [KconfigCheck('cut_attack_surface', 'lockdown', 'BPF_SYSCALL', 'is not set')] # refers to LOCKDOWN
l += [KconfigCheck('cut_attack_surface', 'lockdown', 'MMIOTRACE_TEST', 'is not set')] # refers to LOCKDOWN
l += [KconfigCheck('cut_attack_surface', 'lockdown', 'KPROBES', 'is not set')] # refers to LOCKDOWN
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:
+ if o3.type == 'complex':
+ sys.exit('[!] ERROR: unexpected ComplexOptCheck inside {}'.format(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('[?] No check for option {} ({})'.format(option, value))
def print_checklist(mode, checklist, with_results):
if mode == 'json':
- opts = []
+ output = []
for o in checklist:
- opt = ['CONFIG_'+o.name, o.type, o.expected, o.decision, o.reason]
- if with_results:
- opt.append(o.result)
- opts.append(opt)
- print(json.dumps(opts))
+ output.append(o.json_dump(with_results))
+ print(json.dumps(output))
return
# table header
print('[+] Config check is finished: \'OK\' - {}{} / \'FAIL\' - {}{}'.format(ok_count, ok_suppressed, fail_count, fail_suppressed))
-def populate_opt_with_data(opt, parsed_options, kernel_version):
- if hasattr(opt, 'opts'):
- # prepare ComplexOptCheck
+def populate_simple_opt_with_data(opt, data, data_type):
+ if opt.type == 'complex':
+ sys.exit('[!] ERROR: unexpected ComplexOptCheck {}: {}'.format(opt.name, vars(opt)))
+ if data_type not in TYPES_OF_CHECKS:
+ sys.exit('[!] ERROR: invalid data type "{}"'.format(data_type))
+
+ if data_type != opt.type:
+ return
+
+ if data_type == 'kconfig':
+ opt.state = data.get(opt.name, None)
+ elif data_type == 'version':
+ opt.ver = data
+
+
+def populate_opt_with_data(opt, data, data_type):
+ if opt.type == 'complex':
for o in opt.opts:
- if hasattr(o, 'opts'):
- # Recursion for nested ComplexOptChecks
- populate_opt_with_data(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
+ if o.type == 'complex':
+ # Recursion for nested ComplexOptCheck objects
+ populate_opt_with_data(o, data, data_type)
+ else:
+ populate_simple_opt_with_data(o, data, data_type)
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)
+ if opt.type != 'kconfig':
+ sys.exit('[!] ERROR: bad type "{}" for a simple check {}'.format(opt.type, opt.name))
+ populate_simple_opt_with_data(opt, data, data_type)
-def populate_with_data(checklist, parsed_options, kernel_version):
+def populate_with_data(checklist, data, data_type):
for opt in checklist:
- populate_opt_with_data(opt, parsed_options, kernel_version)
+ populate_opt_with_data(opt, data, data_type)
def perform_checks(checklist):
value = None
if opt_is_on.match(line):
- option, value = line[7:].split('=', 1)
+ option, value = line.split('=', 1)
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 kconfig option "{}"'.format(line))
if option:
parsed_options[option] = value
- return parsed_options
-
def main():
# Report modes:
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')
+ help='check the kernel kconfig 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('[+] Special report mode: {}'.format(mode))
config_checklist = []
if args.config:
if mode != 'json':
- print('[+] Config file to check: {}'.format(args.config))
+ print('[+] Kconfig file to check: {}'.format(args.config))
arch, msg = detect_arch(args.config, supported_archs)
if not 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, kernel_version)
+ populate_with_data(config_checklist, parsed_kconfig_options, 'kconfig')
+ populate_with_data(config_checklist, kernel_version, 'version')
# now everything is ready for performing the checks
perform_checks(config_checklist)
projects / kconfig-hardened-check.git / blobdiff