This module contains knowledge for checks.
"""
-# pylint: disable=missing-function-docstring,line-too-long,invalid-name
+# pylint: disable=missing-function-docstring,line-too-long
# pylint: disable=too-many-branches,too-many-statements,too-many-locals
-from .engine import KconfigCheck, CmdlineCheck, SysctlCheck, VersionCheck, OR, AND
+from typing import List
+from .engine import StrOrNone, ChecklistObjType, KconfigCheck, CmdlineCheck, SysctlCheck, VersionCheck, OR, AND
-def add_kconfig_checks(l, arch):
+def add_kconfig_checks(l: List[ChecklistObjType], arch: str) -> None:
assert(arch), 'empty arch'
# Calling the KconfigCheck class constructor:
efi_not_set = KconfigCheck('-', '-', 'EFI', 'is not set')
cc_is_gcc = KconfigCheck('-', '-', 'CC_IS_GCC', 'y') # exists since v4.18
cc_is_clang = KconfigCheck('-', '-', 'CC_IS_CLANG', 'y') # exists since v4.18
+ if arch in ('X86_64', 'X86_32'):
+ cpu_sup_amd_not_set = KconfigCheck('-', '-', 'CPU_SUP_AMD', 'is not set')
+ cpu_sup_intel_not_set = KconfigCheck('-', '-', 'CPU_SUP_INTEL', 'is not set')
modules_not_set = KconfigCheck('cut_attack_surface', 'kspp', 'MODULES', 'is not set') # radical, but may be useful in some cases
devmem_not_set = KconfigCheck('cut_attack_surface', 'kspp', 'DEVMEM', 'is not set') # refers to LOCKDOWN
if arch in ('X86_64', 'ARM64', 'ARM'):
l += [vmap_stack_is_set]
if arch in ('X86_64', 'X86_32'):
- l += [KconfigCheck('self_protection', 'defconfig', 'SPECULATION_MITIGATIONS', 'y')]
l += [KconfigCheck('self_protection', 'defconfig', 'DEBUG_WX', 'y')]
l += [KconfigCheck('self_protection', 'defconfig', 'WERROR', 'y')]
l += [KconfigCheck('self_protection', 'defconfig', 'X86_MCE', 'y')]
- l += [KconfigCheck('self_protection', 'defconfig', 'X86_MCE_INTEL', 'y')]
- l += [KconfigCheck('self_protection', 'defconfig', 'X86_MCE_AMD', 'y')]
- l += [KconfigCheck('self_protection', 'defconfig', 'RETPOLINE', 'y')]
l += [KconfigCheck('self_protection', 'defconfig', 'SYN_COOKIES', 'y')] # another reason?
microcode_is_set = KconfigCheck('self_protection', 'defconfig', 'MICROCODE', 'y')
l += [microcode_is_set] # is needed for mitigating CPU bugs
l += [OR(KconfigCheck('self_protection', 'defconfig', 'MICROCODE_INTEL', 'y'),
+ cpu_sup_intel_not_set,
AND(microcode_is_set,
VersionCheck((6, 6, 0))))] # MICROCODE_INTEL was included in MICROCODE since v6.6
l += [OR(KconfigCheck('self_protection', 'defconfig', 'MICROCODE_AMD', 'y'),
+ cpu_sup_amd_not_set,
AND(microcode_is_set,
VersionCheck((6, 6, 0))))] # MICROCODE_AMD was included in MICROCODE since v6.6
l += [OR(KconfigCheck('self_protection', 'defconfig', 'X86_SMAP', 'y'),
VersionCheck((5, 19, 0)))] # X86_SMAP is enabled by default since v5.19
l += [OR(KconfigCheck('self_protection', 'defconfig', 'X86_UMIP', 'y'),
KconfigCheck('self_protection', 'defconfig', 'X86_INTEL_UMIP', 'y'))]
+ l += [OR(KconfigCheck('self_protection', 'defconfig', 'X86_MCE_INTEL', 'y'),
+ cpu_sup_intel_not_set)]
+ l += [OR(KconfigCheck('self_protection', 'defconfig', 'X86_MCE_AMD', 'y'),
+ cpu_sup_amd_not_set)]
+ l += [OR(KconfigCheck('self_protection', 'defconfig', 'CPU_MITIGATIONS', 'y'),
+ KconfigCheck('self_protection', 'defconfig', 'SPECULATION_MITIGATIONS', 'y'))]
+ l += [OR(KconfigCheck('self_protection', 'defconfig', 'MITIGATION_RETPOLINE', 'y'),
+ KconfigCheck('self_protection', 'defconfig', 'RETPOLINE', 'y'))]
+ l += [OR(KconfigCheck('self_protection', 'defconfig', 'MITIGATION_RFDS', 'y'),
+ cpu_sup_intel_not_set)]
+ l += [OR(KconfigCheck('self_protection', 'defconfig', 'MITIGATION_SPECTRE_BHI', 'y'),
+ cpu_sup_intel_not_set)]
if arch in ('ARM64', 'ARM'):
l += [KconfigCheck('self_protection', 'defconfig', 'HW_RANDOM_TPM', 'y')]
l += [KconfigCheck('self_protection', 'defconfig', 'IOMMU_DEFAULT_DMA_STRICT', 'y')]
l += [KconfigCheck('self_protection', 'defconfig', 'IOMMU_DEFAULT_PASSTHROUGH', 'is not set')] # true if IOMMU_DEFAULT_DMA_STRICT is set
l += [KconfigCheck('self_protection', 'defconfig', 'STACKPROTECTOR_PER_TASK', 'y')]
if arch == 'X86_64':
- l += [KconfigCheck('self_protection', 'defconfig', 'PAGE_TABLE_ISOLATION', 'y')]
l += [KconfigCheck('self_protection', 'defconfig', 'RANDOMIZE_MEMORY', 'y')]
l += [KconfigCheck('self_protection', 'defconfig', 'X86_KERNEL_IBT', 'y')]
- l += [KconfigCheck('self_protection', 'defconfig', 'CPU_SRSO', 'y')]
+ l += [OR(KconfigCheck('self_protection', 'defconfig', 'MITIGATION_PAGE_TABLE_ISOLATION', 'y'),
+ KconfigCheck('self_protection', 'defconfig', 'PAGE_TABLE_ISOLATION', 'y'))]
+ l += [OR(KconfigCheck('self_protection', 'defconfig', 'MITIGATION_SRSO', 'y'),
+ KconfigCheck('self_protection', 'defconfig', 'CPU_SRSO', 'y'),
+ cpu_sup_amd_not_set)]
l += [AND(KconfigCheck('self_protection', 'defconfig', 'INTEL_IOMMU', 'y'),
iommu_support_is_set)]
l += [AND(KconfigCheck('self_protection', 'defconfig', 'AMD_IOMMU', 'y'),
VersionCheck((6, 6, 8)))] # DEBUG_CREDENTIALS was dropped in v6.6.8
l += [OR(KconfigCheck('self_protection', 'kspp', 'DEBUG_NOTIFIERS', 'y'),
AND(cfi_clang_is_set,
- cfi_clang_permissive_not_set))]
+ cfi_clang_permissive_not_set,
+ cc_is_clang))]
l += [OR(KconfigCheck('self_protection', 'kspp', 'SCHED_STACK_END_CHECK', 'y'),
vmap_stack_is_set)]
kfence_is_set = KconfigCheck('self_protection', 'kspp', 'KFENCE', 'y')
cc_is_gcc)]
l += [KconfigCheck('self_protection', 'kspp', 'RANDOMIZE_KSTACK_OFFSET_DEFAULT', 'y')]
if arch in ('X86_64', 'ARM64'):
- l += [cfi_clang_is_set]
+ l += [AND(cfi_clang_is_set,
+ cc_is_clang)]
l += [AND(cfi_clang_permissive_not_set,
- cfi_clang_is_set)]
+ cfi_clang_is_set,
+ cc_is_clang)]
if arch in ('X86_64', 'X86_32'):
l += [KconfigCheck('self_protection', 'kspp', 'HW_RANDOM_TPM', 'y')]
l += [KconfigCheck('self_protection', 'kspp', 'DEFAULT_MMAP_MIN_ADDR', '65536')]
l += [KconfigCheck('self_protection', 'kspp', 'DEFAULT_MMAP_MIN_ADDR', '32768')]
l += [KconfigCheck('self_protection', 'kspp', 'SYN_COOKIES', 'y')] # another reason?
if arch == 'X86_64':
- l += [KconfigCheck('self_protection', 'kspp', 'SLS', 'y')] # vs CVE-2021-26341 in Straight-Line-Speculation
+ l += [OR(KconfigCheck('self_protection', 'kspp', 'MITIGATION_SLS', 'y'),
+ KconfigCheck('self_protection', 'kspp', 'SLS', 'y'))] # vs CVE-2021-26341 in Straight-Line-Speculation
l += [AND(KconfigCheck('self_protection', 'kspp', 'INTEL_IOMMU_SVM', 'y'),
iommu_support_is_set)]
l += [AND(KconfigCheck('self_protection', 'kspp', 'AMD_IOMMU_V2', 'y'),
l += [KconfigCheck('self_protection', 'kspp', 'SHADOW_CALL_STACK', 'y')]
l += [KconfigCheck('self_protection', 'kspp', 'KASAN_HW_TAGS', 'y')] # see also: kasan=on, kasan.stacktrace=off, kasan.fault=panic
if arch == 'X86_32':
- l += [KconfigCheck('self_protection', 'kspp', 'PAGE_TABLE_ISOLATION', 'y')]
l += [KconfigCheck('self_protection', 'kspp', 'HIGHMEM64G', 'y')]
l += [KconfigCheck('self_protection', 'kspp', 'X86_PAE', 'y')]
+ l += [OR(KconfigCheck('self_protection', 'kspp', 'MITIGATION_PAGE_TABLE_ISOLATION', 'y'),
+ KconfigCheck('self_protection', 'kspp', 'PAGE_TABLE_ISOLATION', 'y'))]
l += [AND(KconfigCheck('self_protection', 'kspp', 'INTEL_IOMMU', 'y'),
iommu_support_is_set)]
l += [OR(KconfigCheck('cut_attack_surface', 'defconfig', 'STRICT_DEVMEM', 'y'),
devmem_not_set)] # refers to LOCKDOWN
if arch in ('X86_64', 'X86_32'):
- l += [KconfigCheck('cut_attack_surface', 'defconfig', 'X86_INTEL_TSX_MODE_OFF', 'y')] # tsx=off
+ l += [OR(KconfigCheck('cut_attack_surface', 'defconfig', 'X86_INTEL_TSX_MODE_OFF', 'y'),
+ cpu_sup_intel_not_set)] # tsx=off
# 'cut_attack_surface', 'kspp'
l += [KconfigCheck('cut_attack_surface', 'kspp', 'SECURITY_DMESG_RESTRICT', 'y')]
l += [KconfigCheck('cut_attack_surface', 'a13xp0p0v', 'KGDB', 'is not set')]
l += [KconfigCheck('cut_attack_surface', 'a13xp0p0v', 'CORESIGHT', 'is not set')]
l += [KconfigCheck('cut_attack_surface', 'a13xp0p0v', 'XFS_SUPPORT_V4', 'is not set')]
+ l += [KconfigCheck('cut_attack_surface', 'a13xp0p0v', 'MODULE_FORCE_LOAD', 'is not set')]
+ l += [KconfigCheck('cut_attack_surface', 'a13xp0p0v', 'BLK_DEV_WRITE_MOUNTED', 'is not set')]
l += [OR(KconfigCheck('cut_attack_surface', 'a13xp0p0v', 'TRIM_UNUSED_KSYMS', 'y'),
modules_not_set)]
- l += [KconfigCheck('cut_attack_surface', 'a13xp0p0v', 'MODULE_FORCE_LOAD', 'is not set')]
+
# 'harden_userspace'
if arch == 'ARM64':
l += [KconfigCheck('harden_userspace', 'defconfig', 'VMSPLIT_3G', 'y')]
l += [KconfigCheck('harden_userspace', 'clipos', 'COREDUMP', 'is not set')]
l += [KconfigCheck('harden_userspace', 'a13xp0p0v', 'ARCH_MMAP_RND_BITS', 'MAX')] # 'MAX' value is refined using ARCH_MMAP_RND_BITS_MAX
+ if arch == 'X86_64':
+ l += [KconfigCheck('harden_userspace', 'a13xp0p0v', 'X86_USER_SHADOW_STACK', 'y')]
-def add_cmdline_checks(l, arch):
+def add_cmdline_checks(l: List[ChecklistObjType], arch: str) -> None:
assert(arch), 'empty arch'
# Calling the CmdlineCheck class constructor:
l += [OR(CmdlineCheck('self_protection', 'defconfig', 'spectre_v2_user', 'is not off'),
AND(CmdlineCheck('self_protection', 'kspp', 'mitigations', 'auto,nosmt'),
CmdlineCheck('self_protection', 'defconfig', 'spectre_v2_user', 'is not set')))]
+ l += [OR(CmdlineCheck('self_protection', 'defconfig', 'spectre_bhi', 'is not off'),
+ AND(KconfigCheck('self_protection', 'defconfig', 'MITIGATION_SPECTRE_BHI', 'y'),
+ CmdlineCheck('self_protection', 'kspp', 'mitigations', 'auto,nosmt'),
+ CmdlineCheck('self_protection', 'defconfig', 'spectre_bhi', 'is not set')))]
l += [OR(CmdlineCheck('self_protection', 'defconfig', 'spec_store_bypass_disable', 'is not off'),
AND(CmdlineCheck('self_protection', 'kspp', 'mitigations', 'auto,nosmt'),
CmdlineCheck('self_protection', 'defconfig', 'spec_store_bypass_disable', 'is not set')))]
l += [OR(CmdlineCheck('self_protection', 'defconfig', 'gather_data_sampling', 'is not off'),
AND(CmdlineCheck('self_protection', 'kspp', 'mitigations', 'auto,nosmt'),
CmdlineCheck('self_protection', 'defconfig', 'gather_data_sampling', 'is not set')))]
+ l += [OR(CmdlineCheck('self_protection', 'defconfig', 'reg_file_data_sampling', 'is not off'),
+ AND(KconfigCheck('self_protection', 'defconfig', 'MITIGATION_RFDS', 'y'),
+ CmdlineCheck('self_protection', 'kspp', 'mitigations', 'auto,nosmt'),
+ CmdlineCheck('self_protection', 'defconfig', 'reg_file_data_sampling', 'is not set')))]
if arch == 'ARM64':
l += [OR(CmdlineCheck('self_protection', 'defconfig', 'kpti', 'is not off'),
AND(CmdlineCheck('self_protection', 'kspp', 'mitigations', 'auto,nosmt'),
# 'cut_attack_surface', 'defconfig'
if arch in ('X86_64', 'X86_32'):
+ tsx_not_set = CmdlineCheck('cut_attack_surface', 'defconfig', 'tsx', 'is not set')
l += [OR(CmdlineCheck('cut_attack_surface', 'defconfig', 'tsx', 'off'),
AND(KconfigCheck('cut_attack_surface', 'defconfig', 'X86_INTEL_TSX_MODE_OFF', 'y'),
- CmdlineCheck('cut_attack_surface', 'defconfig', 'tsx', 'is not set')))]
+ tsx_not_set),
+ AND(KconfigCheck('-', '-', 'CPU_SUP_INTEL', 'is not set'),
+ tsx_not_set))]
# 'cut_attack_surface', 'kspp'
l += [CmdlineCheck('cut_attack_surface', 'kspp', 'nosmt', 'is present')] # slow (high performance penalty)
# 'cut_attack_surface', 'a13xp0p0v'
l += [CmdlineCheck('cut_attack_surface', 'a13xp0p0v', 'sysrq_always_enabled', 'is not set')]
+ l += [OR(CmdlineCheck('cut_attack_surface', 'a13xp0p0v', 'bdev_allow_write_mounted', '0'),
+ AND(KconfigCheck('cut_attack_surface', 'a13xp0p0v', 'BLK_DEV_WRITE_MOUNTED', 'is not set'),
+ CmdlineCheck('cut_attack_surface', 'a13xp0p0v', 'bdev_allow_write_mounted', 'is not set')))]
if arch == 'X86_64':
l += [OR(CmdlineCheck('cut_attack_surface', 'a13xp0p0v', 'ia32_emulation', '0'),
KconfigCheck('cut_attack_surface', 'kspp', 'IA32_EMULATION', 'is not set'),
'pti', # See pti_check_boottime_disable() in arch/x86/mm/pti.c
'spectre_v2', # See spectre_v2_parse_cmdline() in arch/x86/kernel/cpu/bugs.c
'spectre_v2_user', # See spectre_v2_parse_user_cmdline() in arch/x86/kernel/cpu/bugs.c
+ 'spectre_bhi', # See spectre_bhi_parse_cmdline() in arch/x86/kernel/cpu/bugs.c
'spec_store_bypass_disable', # See ssb_parse_cmdline() in arch/x86/kernel/cpu/bugs.c
'l1tf', # See l1tf_cmdline() in arch/x86/kernel/cpu/bugs.c
'mds', # See mds_cmdline() in arch/x86/kernel/cpu/bugs.c
'ssbd', # See parse_spectre_v4_param() in arch/arm64/kernel/proton-pack.c
'spec_rstack_overflow', # See srso_parse_cmdline() in arch/x86/kernel/cpu/bugs.c
'gather_data_sampling', # See gds_parse_cmdline() in arch/x86/kernel/cpu/bugs.c
+ 'reg_file_data_sampling', # See rfds_parse_cmdline() in arch/x86/kernel/cpu/bugs.c
'slub_debug', # See setup_slub_debug() in mm/slub.c
'iommu', # See iommu_setup() in arch/x86/kernel/pci-dma.c
'vsyscall', # See vsyscall_setup() in arch/x86/entry/vsyscall/vsyscall_64.c
]
-def normalize_cmdline_options(option, value):
+def normalize_cmdline_options(option: str, value: str) -> str:
# Don't normalize the cmdline option values if
# the Linux kernel doesn't use kstrtobool() for them
if option in no_kstrtobool_options:
return value
-# TODO: draft of security hardening sysctls:
+# Ideas of security hardening sysctls:
# what about bpf_jit_enable?
# vm.mmap_min_addr has a good value
# nosmt sysfs control file
# kernel.warn_limit (think about a proper value)
# net.ipv4.tcp_syncookies=1 (?)
-def add_sysctl_checks(l, _arch):
+def add_sysctl_checks(l: List[ChecklistObjType], _arch: StrOrNone) -> None:
# This function may be called with arch=None
# Calling the SysctlCheck class constructor:
# SysctlCheck(reason, decision, name, expected)
- l += [SysctlCheck('self_protection', 'kspp', 'net.core.bpf_jit_harden', '2')]
+ # Use an omnipresent kconfig symbol to see if we have a kconfig file for checking
+ have_kconfig = KconfigCheck('-', '-', 'LOCALVERSION', 'is present')
+
+ l += [OR(SysctlCheck('self_protection', 'kspp', 'net.core.bpf_jit_harden', '2'),
+ AND(KconfigCheck('-', '-', 'BPF_JIT', 'is not set'),
+ have_kconfig))]
l += [SysctlCheck('cut_attack_surface', 'kspp', 'kernel.dmesg_restrict', '1')]
l += [SysctlCheck('cut_attack_surface', 'kspp', 'kernel.perf_event_paranoid', '3')] # with a custom patch, see https://lwn.net/Articles/696216/
- l += [SysctlCheck('cut_attack_surface', 'kspp', 'kernel.kexec_load_disabled', '1')]
- l += [SysctlCheck('cut_attack_surface', 'kspp', 'user.max_user_namespaces', '0')]
+ l += [SysctlCheck('cut_attack_surface', 'kspp', 'user.max_user_namespaces', '0')] # may break the upower daemon in Ubuntu
l += [SysctlCheck('cut_attack_surface', 'kspp', 'dev.tty.ldisc_autoload', '0')]
- l += [SysctlCheck('cut_attack_surface', 'kspp', 'kernel.unprivileged_bpf_disabled', '1')]
l += [SysctlCheck('cut_attack_surface', 'kspp', 'kernel.kptr_restrict', '2')]
l += [SysctlCheck('cut_attack_surface', 'kspp', 'dev.tty.legacy_tiocsti', '0')]
- l += [SysctlCheck('cut_attack_surface', 'kspp', 'vm.unprivileged_userfaultfd', '0')]
+ l += [OR(SysctlCheck('cut_attack_surface', 'kspp', 'kernel.kexec_load_disabled', '1'),
+ AND(KconfigCheck('-', '-', 'KEXEC_CORE', 'is not set'),
+ have_kconfig))]
+ l += [OR(SysctlCheck('cut_attack_surface', 'kspp', 'kernel.unprivileged_bpf_disabled', '1'),
+ AND(KconfigCheck('cut_attack_surface', 'lockdown', 'BPF_SYSCALL', 'is not set'),
+ have_kconfig))]
+ l += [OR(SysctlCheck('cut_attack_surface', 'kspp', 'vm.unprivileged_userfaultfd', '0'),
+ AND(KconfigCheck('cut_attack_surface', 'grsec', 'USERFAULTFD', 'is not set'),
+ have_kconfig))]
# At first, it disabled unprivileged userfaultfd,
# and since v5.11 it enables unprivileged userfaultfd for user-mode only.
- l += [SysctlCheck('cut_attack_surface', 'clipos', 'kernel.modules_disabled', '1')] # radical, but may be useful in some cases
+ l += [OR(SysctlCheck('cut_attack_surface', 'clipos', 'kernel.modules_disabled', '1'),
+ AND(KconfigCheck('cut_attack_surface', 'kspp', 'MODULES', 'is not set'),
+ have_kconfig))] # radical, but may be useful in some cases
l += [SysctlCheck('harden_userspace', 'kspp', 'fs.protected_symlinks', '1')]
l += [SysctlCheck('harden_userspace', 'kspp', 'fs.protected_hardlinks', '1')]
projects / kconfig-hardened-check.git / blobdiff