#
#
# N.B Hardening command line parameters:
-# slab_nomerge
# page_alloc.shuffle=1
# iommu=force (does it help against DMA attacks?)
-# iommu.passthrough=0
-# iommu.strict=1
# slub_debug=FZ (slow)
-# init_on_alloc=1 (since v5.3)
-# init_on_free=1 (since v5.3, otherwise slub_debug=P and page_poison=1)
# loadpin.enforce=1
# debugfs=no-mount (or off if possible)
-# randomize_kstack_offset=1
#
# Mitigations of CPU vulnerabilities:
# Аrch-independent:
# mitigations=auto,nosmt (nosmt is slow)
# X86:
# spectre_v2=on
-# pti=on
# spec_store_bypass_disable=on
# l1tf=full,force
# l1d_flush=on (a part of the l1tf option)
#
# Should NOT be set:
# nokaslr
-# rodata=off
# sysrq_always_enabled
# arm64.nobti
# arm64.nopauth
# vm.unprivileged_userfaultfd=0
# (at first, it disabled unprivileged userfaultfd,
# and since v5.11 it enables unprivileged userfaultfd for user-mode only)
+# vm.mmap_min_addr has a good value
# dev.tty.ldisc_autoload=0
# fs.protected_symlinks=1
# fs.protected_hardlinks=1
import json
from .__about__ import __version__
-TYPES_OF_CHECKS = ('kconfig', 'version')
+SIMPLE_OPTION_TYPES = ('kconfig', 'version', 'cmdline')
class OptCheck:
# Constructor without the 'expected' parameter is for option presence checks (any value is OK)
def __init__(self, reason, decision, name, expected=None):
- if not reason or not decision or not name:
- sys.exit('[!] ERROR: invalid {} check for "{}"'.format(self.__class__.__name__, name))
+ assert(reason and decision and name), \
+ 'invalid {} check for "{}"'.format(self.__class__.__name__, name)
self.name = name
self.expected = expected
self.decision = decision
class ComplexOptCheck:
def __init__(self, *opts):
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) and not isinstance(opts[0], CmdlineCheck):
- sys.exit('[!] ERROR: invalid {} check: {}'.format(self.__class__.__name__, opts))
+ assert(self.opts), \
+ 'empty {} check'.format(self.__class__.__name__)
+ assert(len(self.opts) != 1), \
+ 'useless {} check: {}'.format(self.__class__.__name__, opts)
+ assert(isinstance(opts[0], (KconfigCheck, CmdlineCheck))), \
+ 'invalid {} check: {}'.format(self.__class__.__name__, opts)
self.result = None
- @property
- def name(self):
- return self.opts[0].name
-
@property
def type(self):
return 'complex'
@property
- def expected(self):
- return self.opts[0].expected
-
- @property
- def decision(self):
- return self.opts[0].decision
+ def name(self):
+ return self.opts[0].name
@property
- def reason(self):
- return self.opts[0].reason
+ def expected(self):
+ return self.opts[0].expected
def table_print(self, mode, with_results):
if mode == 'verbose':
# 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):
opt.check()
if opt.result.startswith('OK'):
self.result = 'OK: {} not found'.format(opt.name)
elif opt.result == 'OK: is present':
self.result = 'OK: {} is present'.format(opt.name)
- # VersionCheck provides enough info
- elif not opt.result.startswith('OK: version'):
- sys.exit('[!] ERROR: unexpected OK description "{}"'.format(opt.result))
+ else:
+ # VersionCheck provides enough info
+ assert(opt.result.startswith('OK: version')), \
+ 'unexpected OK description "{}"'.format(opt.result)
return
self.result = self.opts[0].result
else:
# VersionCheck provides enough info
self.result = opt.result
- if not opt.result.startswith('FAIL: version'):
- sys.exit('[!] ERROR: unexpected FAIL description "{}"'.format(opt.result))
+ assert(opt.result.startswith('FAIL: version')), \
+ 'unexpected FAIL description "{}"'.format(opt.result)
return
- sys.exit('[!] ERROR: invalid AND check')
def detect_arch(fname, archs):
def add_kconfig_checks(l, arch):
# Calling the KconfigCheck class constructor:
# KconfigCheck(reason, decision, name, expected)
+ #
+ # [!] Don't add CmdlineChecks in add_kconfig_checks() to avoid wrong results
+ # when the tool doesn't check the cmdline.
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
l += [KconfigCheck('self_protection', 'defconfig', 'SLUB_DEBUG', 'y')]
l += [KconfigCheck('self_protection', 'defconfig', 'GCC_PLUGINS', 'y')]
l += [OR(KconfigCheck('self_protection', 'defconfig', 'STACKPROTECTOR', 'y'),
- KconfigCheck('self_protection', 'defconfig', 'CC_STACKPROTECTOR', 'y'))]
+ KconfigCheck('self_protection', 'defconfig', 'CC_STACKPROTECTOR', 'y'),
+ KconfigCheck('self_protection', 'defconfig', 'CC_STACKPROTECTOR_REGULAR', 'y'),
+ KconfigCheck('self_protection', 'defconfig', 'CC_STACKPROTECTOR_AUTO', 'y'),
+ KconfigCheck('self_protection', 'defconfig', 'CC_STACKPROTECTOR_STRONG', 'y'))]
l += [OR(KconfigCheck('self_protection', 'defconfig', 'STACKPROTECTOR_STRONG', 'y'),
KconfigCheck('self_protection', 'defconfig', 'CC_STACKPROTECTOR_STRONG', 'y'))]
l += [OR(KconfigCheck('self_protection', 'defconfig', 'STRICT_KERNEL_RWX', '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', 'BUG_ON_DATA_CORRUPTION', 'y')]
l += [KconfigCheck('self_protection', 'kspp', 'DEBUG_WX', 'y')]
l += [KconfigCheck('self_protection', 'kspp', 'SCHED_STACK_END_CHECK', 'y')]
l += [KconfigCheck('self_protection', 'kspp', 'KFENCE', 'y')]
l += [KconfigCheck('self_protection', 'kspp', 'WERROR', 'y')]
l += [KconfigCheck('self_protection', 'kspp', 'IOMMU_DEFAULT_DMA_STRICT', 'y')]
+ l += [KconfigCheck('self_protection', 'kspp', 'IOMMU_DEFAULT_PASSTHROUGH', 'is not set')] # true if IOMMU_DEFAULT_DMA_STRICT is set
l += [KconfigCheck('self_protection', 'kspp', 'ZERO_CALL_USED_REGS', 'y')]
randstruct_is_set = KconfigCheck('self_protection', 'kspp', 'GCC_PLUGIN_RANDSTRUCT', 'y')
l += [randstruct_is_set]
l += [KconfigCheck('self_protection', 'clipos', 'STATIC_USERMODEHELPER', 'y')] # needs userspace support
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', 'SLAB_MERGE_DEFAULT', 'is not set')]
l += [KconfigCheck('self_protection', 'clipos', 'RANDOM_TRUST_BOOTLOADER', 'is not set')]
l += [KconfigCheck('self_protection', 'clipos', 'RANDOM_TRUST_CPU', 'is not set')]
l += [AND(KconfigCheck('self_protection', 'clipos', 'GCC_PLUGIN_RANDSTRUCT_PERFORMANCE', 'is not set'),
devmem_not_set)] # refers to LOCKDOWN
# 'cut_attack_surface', 'kspp'
+ l += [KconfigCheck('cut_attack_surface', 'kspp', 'SECURITY_DMESG_RESTRICT', 'y')]
l += [KconfigCheck('cut_attack_surface', 'kspp', 'ACPI_CUSTOM_METHOD', 'is not set')] # refers to LOCKDOWN
l += [KconfigCheck('cut_attack_surface', 'kspp', 'COMPAT_BRK', 'is not set')]
l += [KconfigCheck('cut_attack_surface', 'kspp', 'DEVKMEM', 'is not set')] # refers to LOCKDOWN
l += [KconfigCheck('harden_userspace', 'defconfig', 'INTEGRITY', 'y')]
if arch == 'ARM':
l += [KconfigCheck('harden_userspace', 'my', 'INTEGRITY', 'y')]
+ if arch == 'ARM64':
+ l += [KconfigCheck('harden_userspace', 'defconfig', 'ARM64_PTR_AUTH', 'y')]
+ l += [KconfigCheck('harden_userspace', 'defconfig', 'ARM64_BTI', 'y')]
if arch in ('ARM', 'X86_32'):
l += [KconfigCheck('harden_userspace', 'defconfig', 'VMSPLIT_3G', 'y')]
if arch in ('X86_64', 'ARM64'):
if arch in ('X86_32', 'ARM'):
l += [KconfigCheck('harden_userspace', 'my', 'ARCH_MMAP_RND_BITS', '16')]
-# l += [KconfigCheck('feature_test', 'my', 'LKDTM', 'm')] # only for debugging!
-
def add_cmdline_checks(l, arch):
# Calling the CmdlineCheck class constructor:
# CmdlineCheck(reason, decision, name, expected)
+ #
+ # [!] Don't add CmdlineChecks in add_kconfig_checks() to avoid wrong results
+ # when the tool doesn't check the cmdline.
+ #
+ # [!] Make sure that values of the options in CmdlineChecks need normalization.
+ # For more info see normalize_cmdline_options().
+ #
+ # A common pattern for checking the 'param_x' cmdline parameter
+ # that __overrides__ the 'PARAM_X_DEFAULT' kconfig option:
+ # l += [OR(CmdlineCheck(reason, decision, 'param_x', '1'),
+ # AND(KconfigCheck(reason, decision, 'PARAM_X_DEFAULT_ON', 'y'),
+ # CmdlineCheck(reason, decision, 'param_x, 'is not set')))]
+ #
+ # Here we don't check the kconfig options or minimal kernel version
+ # required for the cmdline parameters. That would make the checks
+ # very complex and not give a 100% guarantee anyway.
+
+ if arch == 'ARM64':
+ l += [OR(CmdlineCheck('self_protection', 'defconfig', 'rodata', 'full'),
+ AND(KconfigCheck('self_protection', 'defconfig', 'RODATA_FULL_DEFAULT_ENABLED', 'y'),
+ CmdlineCheck('self_protection', 'defconfig', 'rodata', 'is not set')))]
+ else:
+ l += [OR(CmdlineCheck('self_protection', 'defconfig', 'rodata', '1'),
+ CmdlineCheck('self_protection', 'defconfig', 'rodata', 'is not set'))]
+
+ l += [OR(CmdlineCheck('self_protection', 'kspp', 'init_on_alloc', '1'),
+ AND(KconfigCheck('self_protection', 'kspp', 'INIT_ON_ALLOC_DEFAULT_ON', 'y'),
+ CmdlineCheck('self_protection', 'kspp', 'init_on_alloc', 'is not set')))]
+ l += [OR(CmdlineCheck('self_protection', 'kspp', 'init_on_free', '1'),
+ AND(KconfigCheck('self_protection', 'kspp', 'INIT_ON_FREE_DEFAULT_ON', 'y'),
+ CmdlineCheck('self_protection', 'kspp', 'init_on_free', 'is not set')),
+ AND(CmdlineCheck('self_protection', 'kspp', 'page_poison', '1'),
+ KconfigCheck('self_protection', 'kspp', 'PAGE_POISONING_ZERO', 'y'),
+ CmdlineCheck('self_protection', 'kspp', 'slub_debug', 'P')))]
+ l += [OR(CmdlineCheck('self_protection', 'kspp', 'slab_nomerge'),
+ AND(KconfigCheck('self_protection', 'clipos', 'SLAB_MERGE_DEFAULT', 'is not set'),
+ CmdlineCheck('self_protection', 'kspp', 'slab_merge', 'is not set')))] # option presence check
+ l += [OR(CmdlineCheck('self_protection', 'kspp', 'iommu.strict', '1'),
+ AND(KconfigCheck('self_protection', 'kspp', 'IOMMU_DEFAULT_DMA_STRICT', 'y'),
+ CmdlineCheck('self_protection', 'kspp', 'iommu.strict', 'is not set')))]
+ l += [OR(CmdlineCheck('self_protection', 'kspp', 'iommu.passthrough', '0'),
+ AND(KconfigCheck('self_protection', 'kspp', 'IOMMU_DEFAULT_PASSTHROUGH', 'is not set'),
+ CmdlineCheck('self_protection', 'kspp', 'iommu.passthrough', 'is not set')))]
+ l += [OR(CmdlineCheck('self_protection', 'kspp', 'hardened_usercopy', '1'),
+ AND(KconfigCheck('self_protection', 'kspp', 'HARDENED_USERCOPY', 'y'),
+ CmdlineCheck('self_protection', 'kspp', 'hardened_usercopy', 'is not set')))]
+ l += [OR(CmdlineCheck('self_protection', 'kspp', 'slab_common.usercopy_fallback', '0'),
+ AND(KconfigCheck('self_protection', 'kspp', 'HARDENED_USERCOPY_FALLBACK', 'is not set'),
+ CmdlineCheck('self_protection', 'kspp', 'slab_common.usercopy_fallback', 'is not set')))]
+ if arch in ('X86_64', 'ARM64', 'X86_32'):
+ l += [OR(CmdlineCheck('self_protection', 'kspp', 'randomize_kstack_offset', '1'),
+ AND(KconfigCheck('self_protection', 'kspp', 'RANDOMIZE_KSTACK_OFFSET_DEFAULT', 'y'),
+ CmdlineCheck('self_protection', 'kspp', 'randomize_kstack_offset', 'is not set')))]
+ if arch in ('X86_64', 'X86_32'):
+ l += [CmdlineCheck('self_protection', 'kspp', 'pti', 'on')]
+
+ if arch == 'X86_64':
+ l += [OR(CmdlineCheck('cut_attack_surface', 'kspp', 'vsyscall', 'none'),
+ AND(KconfigCheck('cut_attack_surface', 'kspp', 'LEGACY_VSYSCALL_NONE', 'y'),
+ CmdlineCheck('cut_attack_surface', 'kspp', 'vsyscall', 'is not set')))]
- l += [CmdlineCheck('self_protection', 'kspp', 'randomize_kstack_offset', 'on')]
# TODO: add other
known_options.append(o2.name)
continue
for o3 in o2.opts:
- if o3.type == 'complex':
- sys.exit('[!] ERROR: unexpected ComplexOptCheck inside {}'.format(o2.name))
+ assert(o3.type != 'complex'), \
+ 'unexpected ComplexOptCheck inside {}'.format(o2.name)
if hasattr(o3, 'name'):
known_options.append(o3.name)
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 opt.type not in TYPES_OF_CHECKS:
- sys.exit('[!] ERROR: invalid opt type "{}" for {}'.format(opt.type, opt.name))
- if data_type not in TYPES_OF_CHECKS:
- sys.exit('[!] ERROR: invalid data type "{}"'.format(data_type))
+ assert(opt.type != 'complex'), \
+ 'unexpected ComplexOptCheck "{}"'.format(opt.name)
+ assert(opt.type in SIMPLE_OPTION_TYPES), \
+ 'invalid opt type "{}"'.format(opt.type)
+ assert(data_type in SIMPLE_OPTION_TYPES), \
+ 'invalid data type "{}"'.format(data_type)
if data_type != opt.type:
return
- if data_type == 'kconfig':
+ if data_type in ('kconfig', 'cmdline'):
opt.state = data.get(opt.name, None)
- elif data_type == 'version':
- opt.ver = data
else:
- sys.exit('[!] ERROR: unexpected data type "{}"'.format(data_type))
+ assert(data_type == 'version'), \
+ 'unexpected data type "{}"'.format(data_type)
+ opt.ver = data
def populate_opt_with_data(opt, data, data_type):
else:
populate_simple_opt_with_data(o, data, data_type)
else:
- if opt.type != 'kconfig':
- sys.exit('[!] ERROR: bad type "{}" for a simple check {}'.format(opt.type, opt.name))
+ assert(opt.type in ('kconfig', 'cmdline')), \
+ 'bad type "{}" for a simple check'.format(opt.type)
populate_simple_opt_with_data(opt, data, data_type)
if opt_is_on.match(line):
option, value = line.split('=', 1)
+ if value == 'is not set':
+ sys.exit('[!] ERROR: bad enabled kconfig option "{}"'.format(line))
elif opt_is_off.match(line):
option, value = line[2:].split(' ', 1)
if value != 'is not set':
parsed_options[option] = value
+def normalize_cmdline_options(option, value):
+ # Handle special cases
+ if option == 'pti':
+ # Don't normalize the pti value since
+ # the Linux kernel doesn't use kstrtobool() for pti.
+ # See pti_check_boottime_disable() in linux/arch/x86/mm/pti.c
+ return value
+
+ # Implement a limited part of the kstrtobool() logic
+ if value in ('1', 'on', 'On', 'ON', 'y', 'Y', 'yes', 'Yes', 'YES'):
+ return '1'
+ if value in ('0', 'off', 'Off', 'OFF', 'n', 'N', 'no', 'No', 'NO'):
+ return '0'
+
+ # Preserve unique values
+ return value
+
+
+def parse_cmdline_file(parsed_options, fname):
+ with open(fname, 'r') as f:
+ line = f.readline()
+ opts = line.split()
+
+ line = f.readline()
+ if line:
+ sys.exit('[!] ERROR: more than one line in "{}"'.format(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
config_checklist = []
if args.config:
+ if args.print:
+ sys.exit('[!] ERROR: --config and --print can\'t be used together')
+
if mode != 'json':
print('[+] Kconfig file to check: {}'.format(args.config))
if args.cmdline:
# 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_with_data(config_checklist, kernel_version, 'version')
+ if args.cmdline:
+ # populate the checklist with the parsed kconfig 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 for performing the checks
perform_checks(config_checklist)
parser.print_help()
sys.exit(0)
-
-if __name__ == '__main__':
- main()
projects / kconfig-hardened-check.git / blobdiff