#
#
# N.B Hardening command line parameters:
-# page_alloc.shuffle=1
# iommu=force (does it help against DMA attacks?)
-# slub_debug=FZ (slow)
# loadpin.enforce=1
-# debugfs=no-mount (or off if possible)
#
# Mitigations of CPU vulnerabilities:
# Аrch-independent:
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
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.
+ #
+ # [!] 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.
+ # 'self_protection', 'defconfig'
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'))]
+ # 'self_protection', 'kspp'
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', 'iommu.passthrough', '0'),
AND(KconfigCheck('self_protection', 'kspp', 'IOMMU_DEFAULT_PASSTHROUGH', 'is not set'),
CmdlineCheck('self_protection', 'kspp', 'iommu.passthrough', 'is not set')))]
+ # The cmdline checks compatible with the kconfig recommendations of the KSPP project...
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')))]
+ CmdlineCheck('self_protection', 'kspp', 'slab_common.usercopy_fallback', 'is not set')))] # ... the end
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'),
if arch in ('X86_64', 'X86_32'):
l += [CmdlineCheck('self_protection', 'kspp', 'pti', 'on')]
+ # 'self_protection', 'clipos'
+ l += [CmdlineCheck('self_protection', 'clipos', 'page_alloc.shuffle', '1')]
+
+ # 'cut_attack_surface', 'kspp'
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')))]
- # TODO: add other
+ # 'cut_attack_surface', 'grsec'
+ # The cmdline checks compatible with the kconfig options disabled by grsecurity...
+ l += [OR(CmdlineCheck('cut_attack_surface', 'grsec', 'debugfs', 'off'),
+ KconfigCheck('cut_attack_surface', 'grsec', 'DEBUG_FS', 'is not set'))] # ... the end
def print_unknown_options(checklist, parsed_options):
parsed_options[option] = value
+def normalize_cmdline_options(option, value):
+ # Don't normalize the cmdline option values if
+ # the Linux kernel doesn't use kstrtobool() for them
+ if option == 'pti':
+ # See pti_check_boottime_disable() in linux/arch/x86/mm/pti.c
+ return value
+ if option == 'debugfs':
+ # See debugfs_kernel() in fs/debugfs/inode.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()
else:
name = opt
value = '' # '' is not None
+ value = normalize_cmdline_options(name, value)
parsed_options[name] = value
projects / kconfig-hardened-check.git / blobdiff