-#!/usr/bin/python3
+#!/usr/bin/env python3
"""
This tool is for checking the security hardening options of the Linux kernel.
cc_is_gcc = KconfigCheck('-', '-', 'CC_IS_GCC', 'y') # exists since v4.18
cc_is_clang = KconfigCheck('-', '-', 'CC_IS_CLANG', 'y') # exists since v4.18
- modules_not_set = KconfigCheck('cut_attack_surface', 'kspp', 'MODULES', '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
bpf_syscall_not_set = KconfigCheck('cut_attack_surface', 'lockdown', 'BPF_SYSCALL', 'is not set') # refers to LOCKDOWN
if arch in ('X86_64', 'ARM64', 'ARM'):
l += [KconfigCheck('self_protection', 'defconfig', 'VMAP_STACK', 'y')]
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', 'MICROCODE', 'y')] # is needed for mitigating CPU bugs
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'),
+ AND(microcode_is_set,
+ VersionCheck((6, 6))))] # MICROCODE_INTEL was included in MICROCODE since v6.6
+ l += [OR(KconfigCheck('self_protection', 'defconfig', 'MICROCODE_AMD', 'y'),
+ AND(microcode_is_set,
+ VersionCheck((6, 6))))] # MICROCODE_AMD was included in MICROCODE since v6.6
l += [OR(KconfigCheck('self_protection', 'defconfig', 'X86_SMAP', 'y'),
VersionCheck((5, 19)))] # X86_SMAP is enabled by default since v5.19
l += [OR(KconfigCheck('self_protection', 'defconfig', 'X86_UMIP', 'y'),
l += [KconfigCheck('self_protection', 'kspp', 'DEBUG_CREDENTIALS', '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', 'KFENCE', 'y')]
- l += [KconfigCheck('self_protection', 'kspp', 'ZERO_CALL_USED_REGS', 'y')]
l += [KconfigCheck('self_protection', 'kspp', 'HW_RANDOM_TPM', 'y')]
l += [KconfigCheck('self_protection', 'kspp', 'STATIC_USERMODEHELPER', 'y')] # needs userspace support
+ kfence_is_set = KconfigCheck('self_protection', 'kspp', 'KFENCE', 'y')
+ l += [kfence_is_set]
+ l += [AND(KconfigCheck('self_protection', 'my', 'KFENCE_SAMPLE_INTERVAL', 'is not off'),
+ kfence_is_set)]
randstruct_is_set = OR(KconfigCheck('self_protection', 'kspp', 'RANDSTRUCT_FULL', 'y'),
KconfigCheck('self_protection', 'kspp', 'GCC_PLUGIN_RANDSTRUCT', 'y'))
l += [randstruct_is_set]
l += [KconfigCheck('cut_attack_surface', 'kspp', 'COMPAT_VDSO', 'is not set')]
# CONFIG_COMPAT_VDSO disabled ASLR of vDSO only on X86_64 and X86_32;
# on ARM64 this option has different meaning
+ if arch == 'X86_64':
+ l += [OR(KconfigCheck('cut_attack_surface', 'kspp', 'X86_VSYSCALL_EMULATION', 'is not set'),
+ KconfigCheck('cut_attack_surface', 'kspp', 'LEGACY_VSYSCALL_NONE', 'y'))]
+ # disabling X86_VSYSCALL_EMULATION turns vsyscall off completely,
+ # and LEGACY_VSYSCALL_NONE can be changed at boot time via the cmdline parameter
if arch == 'ARM':
l += [OR(KconfigCheck('cut_attack_surface', 'kspp', 'STRICT_DEVMEM', 'y'),
devmem_not_set)] # refers to LOCKDOWN
l += [KconfigCheck('cut_attack_surface', 'clipos', 'X86_IOPL_IOPERM', 'is not set')] # refers to LOCKDOWN
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 += [KconfigCheck('cut_attack_surface', 'clipos', 'COREDUMP', 'is not set')] # cut userspace attack surface
# l += [KconfigCheck('cut_attack_surface', 'clipos', 'IKCONFIG', 'is not set')] # no, IKCONFIG is needed for this check :)
- if arch == 'X86_64':
- l += [OR(KconfigCheck('cut_attack_surface', 'clipos', 'X86_VSYSCALL_EMULATION', 'is not set'),
- KconfigCheck('cut_attack_surface', 'kspp', 'LEGACY_VSYSCALL_NONE', 'y'))]
- # disabling X86_VSYSCALL_EMULATION turns vsyscall off completely,
- # and LEGACY_VSYSCALL_NONE can be changed at boot time via the cmdline parameter
# 'cut_attack_surface', 'lockdown'
l += [KconfigCheck('cut_attack_surface', 'lockdown', 'EFI_TEST', 'is not set')] # refers to LOCKDOWN
l += [KconfigCheck('cut_attack_surface', 'my', 'XFS_SUPPORT_V4', 'is not set')]
l += [OR(KconfigCheck('cut_attack_surface', 'my', 'TRIM_UNUSED_KSYMS', 'y'),
modules_not_set)]
+ l += [KconfigCheck('cut_attack_surface', 'my', 'MODULE_FORCE_LOAD', 'is not set')]
# 'harden_userspace'
if arch == 'ARM64':
l += [KconfigCheck('harden_userspace', 'defconfig', 'ARM64_BTI', 'y')]
if arch in ('ARM', 'X86_32'):
l += [KconfigCheck('harden_userspace', 'defconfig', 'VMSPLIT_3G', 'y')]
+ l += [KconfigCheck('harden_userspace', 'clipos', 'COREDUMP', 'is not set')]
l += [KconfigCheck('harden_userspace', 'my', 'ARCH_MMAP_RND_BITS', 'MAX')] # 'MAX' value is refined using ARCH_MMAP_RND_BITS_MAX
l += [CmdlineCheck('self_protection', 'defconfig', 'nospectre_v2', 'is not set')]
l += [CmdlineCheck('self_protection', 'defconfig', 'nospectre_bhb', 'is not set')]
l += [CmdlineCheck('self_protection', 'defconfig', 'nospec_store_bypass_disable', 'is not set')]
+ l += [CmdlineCheck('self_protection', 'defconfig', 'dis_ucode_ldr', 'is not set')]
l += [CmdlineCheck('self_protection', 'defconfig', 'arm64.nobti', 'is not set')]
l += [CmdlineCheck('self_protection', 'defconfig', 'arm64.nopauth', 'is not set')]
l += [CmdlineCheck('self_protection', 'defconfig', 'arm64.nomte', 'is not set')]
l += [OR(CmdlineCheck('self_protection', 'defconfig', 'retbleed', 'is not off'),
AND(CmdlineCheck('self_protection', 'kspp', 'mitigations', 'auto,nosmt'),
CmdlineCheck('self_protection', 'defconfig', 'retbleed', 'is not set')))]
+ l += [OR(CmdlineCheck('self_protection', 'defconfig', 'spec_rstack_overflow', 'is not off'),
+ AND(CmdlineCheck('self_protection', 'kspp', 'mitigations', 'auto,nosmt'),
+ CmdlineCheck('self_protection', 'defconfig', 'spec_rstack_overflow', 'is not set')))]
if arch == 'ARM64':
l += [OR(CmdlineCheck('self_protection', 'defconfig', 'kpti', 'is not off'),
AND(CmdlineCheck('self_protection', 'kspp', 'mitigations', 'auto,nosmt'),
CmdlineCheck('self_protection', 'defconfig', 'rodata', 'is not set'))]
# 'self_protection', 'kspp'
- l += [CmdlineCheck('self_protection', 'kspp', 'nosmt', 'is present')]
- l += [CmdlineCheck('self_protection', 'kspp', 'mitigations', 'auto,nosmt')] # 'nosmt' by kspp + 'auto' by defconfig
+ l += [CmdlineCheck('self_protection', 'kspp', 'mitigations', 'auto,nosmt')]
l += [CmdlineCheck('self_protection', 'kspp', 'slab_merge', 'is not set')] # consequence of 'slab_nomerge' by kspp
l += [CmdlineCheck('self_protection', 'kspp', 'slub_merge', 'is not set')] # consequence of 'slab_nomerge' by kspp
+ l += [CmdlineCheck('self_protection', 'kspp', 'page_alloc.shuffle', '1')]
l += [OR(CmdlineCheck('self_protection', 'kspp', 'slab_nomerge', 'is present'),
AND(KconfigCheck('self_protection', 'clipos', 'SLAB_MERGE_DEFAULT', 'is not set'),
CmdlineCheck('self_protection', 'kspp', 'slab_merge', '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')))]
- # 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')))]
- # ... the end
+ l += [AND(CmdlineCheck('self_protection', 'kspp', 'slab_common.usercopy_fallback', 'is not set'),
+ KconfigCheck('self_protection', 'kspp', 'HARDENED_USERCOPY_FALLBACK', 'is not set'))]
+ # don't require slab_common.usercopy_fallback=0,
+ # since HARDENED_USERCOPY_FALLBACK was removed in Linux v5.16
if arch in ('X86_64', 'ARM64', 'X86_32'):
l += [OR(CmdlineCheck('self_protection', 'kspp', 'iommu.strict', '1'),
AND(KconfigCheck('self_protection', 'kspp', 'IOMMU_DEFAULT_DMA_STRICT', 'y'),
CmdlineCheck('self_protection', 'defconfig', 'nopti', 'is not set'))]
# 'self_protection', 'clipos'
- l += [CmdlineCheck('self_protection', 'clipos', 'page_alloc.shuffle', '1')]
if arch in ('X86_64', 'X86_32'):
l += [CmdlineCheck('self_protection', 'clipos', 'iommu', 'force')]
+ # 'self_protection', 'my'
+ l += [OR(CmdlineCheck('self_protection', 'my', 'kfence.sample_interval', 'is not off'),
+ AND(KconfigCheck('self_protection', 'my', 'KFENCE_SAMPLE_INTERVAL', 'is not off'),
+ CmdlineCheck('self_protection', 'my', 'kfence.sample_interval', 'is not set')))]
+
# 'cut_attack_surface', 'defconfig'
if arch in ('X86_64', 'X86_32'):
l += [OR(CmdlineCheck('cut_attack_surface', 'defconfig', 'tsx', 'off'),
CmdlineCheck('cut_attack_surface', 'defconfig', 'tsx', 'is not set')))]
# 'cut_attack_surface', 'kspp'
+ l += [CmdlineCheck('cut_attack_surface', 'kspp', 'nosmt', 'is present')] # slow (high performance penalty)
if arch == 'X86_64':
l += [OR(CmdlineCheck('cut_attack_surface', 'kspp', 'vsyscall', 'none'),
- KconfigCheck('cut_attack_surface', 'clipos', 'X86_VSYSCALL_EMULATION', 'is not set'),
+ KconfigCheck('cut_attack_surface', 'kspp', 'X86_VSYSCALL_EMULATION', 'is not set'),
AND(KconfigCheck('cut_attack_surface', 'kspp', 'LEGACY_VSYSCALL_NONE', 'y'),
CmdlineCheck('cut_attack_surface', 'kspp', 'vsyscall', 'is not set')))]
l += [OR(CmdlineCheck('cut_attack_surface', 'my', 'vdso32', '1'),
'retbleed', # See retbleed_parse_cmdline() in arch/x86/kernel/cpu/bugs.c
'rodata', # See set_debug_rodata() in init/main.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
'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
# TODO: draft of security hardening sysctls:
-# kernel.kptr_restrict=2 (or 1?)
-# kernel.yama.ptrace_scope=3
# what about bpf_jit_enable?
-# 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
-# fs.protected_symlinks=1
-# fs.protected_hardlinks=1
-# fs.protected_fifos=2
-# fs.protected_regular=2
-# fs.suid_dumpable=0
-# kernel.modules_disabled=1
-# kernel.randomize_va_space=2
# nosmt sysfs control file
-# dev.tty.legacy_tiocsti=0
# vm.mmap_rnd_bits=max (?)
# kernel.sysrq=0
# abi.vsyscall32 (any value except 2)
l += [SysctlCheck('cut_attack_surface', 'kspp', 'user.max_user_namespaces', '0')]
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')]
+ # 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 += [SysctlCheck('harden_userspace', 'kspp', 'fs.protected_symlinks', '1')]
+ l += [SysctlCheck('harden_userspace', 'kspp', 'fs.protected_hardlinks', '1')]
+ l += [SysctlCheck('harden_userspace', 'kspp', 'fs.protected_fifos', '2')]
+ l += [SysctlCheck('harden_userspace', 'kspp', 'fs.protected_regular', '2')]
+ l += [SysctlCheck('harden_userspace', 'kspp', 'fs.suid_dumpable', '0')]
+ l += [SysctlCheck('harden_userspace', 'kspp', 'kernel.randomize_va_space', '2')]
+ l += [SysctlCheck('harden_userspace', 'kspp', 'kernel.yama.ptrace_scope', '3')]
projects / kconfig-hardened-check.git / blobdiff