X-Git-Url: https://jxself.org/git/?a=blobdiff_plain;f=kconfig_hardened_check%2Fchecks.py;h=d857ad132c5658f04641564208920c0feea2a95e;hb=78675ceec3da0a4e99fe9cf5389078e50c14ef95;hp=8942124ef64a7aeb7dca0aac9ccfab321df054b3;hpb=798f7d4570224f03e21cceea10d5b6b3c5260da1;p=kconfig-hardened-check.git diff --git a/kconfig_hardened_check/checks.py b/kconfig_hardened_check/checks.py index 8942124..d857ad1 100644 --- a/kconfig_hardened_check/checks.py +++ b/kconfig_hardened_check/checks.py @@ -1,50 +1,15 @@ #!/usr/bin/python3 """ -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! +This tool is for checking the security hardening options of the Linux kernel. Author: Alexander Popov This module contains knowledge for checks. """ -# N.B. Hardening sysctls: -# kernel.kptr_restrict=2 (or 1?) -# kernel.dmesg_restrict=1 (also see the kconfig option) -# kernel.perf_event_paranoid=2 (or 3 with a custom patch, see https://lwn.net/Articles/696216/) -# kernel.kexec_load_disabled=1 -# kernel.yama.ptrace_scope=3 -# user.max_user_namespaces=0 -# what about bpf_jit_enable? -# kernel.unprivileged_bpf_disabled=1 -# net.core.bpf_jit_harden=2 -# 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 -# 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 -# -# Think of these boot params: -# module.sig_enforce=1 -# lockdown=confidentiality -# mce=0 -# nosmt=force -# intel_iommu=on -# amd_iommu=on -# efi=disable_early_pci_dma - -# pylint: disable=missing-module-docstring,missing-class-docstring,missing-function-docstring -# pylint: disable=line-too-long,invalid-name,too-many-branches,too-many-statements +# pylint: disable=missing-function-docstring,line-too-long,invalid-name +# pylint: disable=too-many-branches,too-many-statements from .engine import KconfigCheck, CmdlineCheck, VersionCheck, OR, AND @@ -110,6 +75,7 @@ def add_kconfig_checks(l, arch): 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 += [AND(KconfigCheck('self_protection', 'defconfig', 'INTEL_IOMMU', 'y'), iommu_support_is_set)] l += [AND(KconfigCheck('self_protection', 'defconfig', 'AMD_IOMMU', 'y'), @@ -134,6 +100,7 @@ def add_kconfig_checks(l, arch): 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')] + l += [KconfigCheck('self_protection', 'defconfig', 'DEBUG_ALIGN_RODATA', 'y')] # 'self_protection', 'kspp' l += [KconfigCheck('self_protection', 'kspp', 'BUG_ON_DATA_CORRUPTION', 'y')] @@ -161,9 +128,9 @@ def add_kconfig_checks(l, arch): hardened_usercopy_is_set = KconfigCheck('self_protection', 'kspp', 'HARDENED_USERCOPY', 'y') l += [hardened_usercopy_is_set] l += [AND(KconfigCheck('self_protection', 'kspp', 'HARDENED_USERCOPY_FALLBACK', 'is not set'), - hardened_usercopy_is_set)] + hardened_usercopy_is_set)] # usercopy whitelist violations should be prohibited l += [AND(KconfigCheck('self_protection', 'kspp', 'HARDENED_USERCOPY_PAGESPAN', 'is not set'), - hardened_usercopy_is_set)] + hardened_usercopy_is_set)] # this debugging for HARDENED_USERCOPY is not needed for security l += [AND(KconfigCheck('self_protection', 'kspp', 'GCC_PLUGIN_LATENT_ENTROPY', 'y'), gcc_plugins_support_is_set)] l += [OR(KconfigCheck('self_protection', 'kspp', 'MODULE_SIG', 'y'), @@ -251,9 +218,9 @@ def add_kconfig_checks(l, arch): # 'security_policy' if arch in ('X86_64', 'ARM64', 'X86_32'): - l += [KconfigCheck('security_policy', 'defconfig', 'SECURITY', 'y')] # and choose your favourite LSM + l += [KconfigCheck('security_policy', 'defconfig', 'SECURITY', 'y')] if arch == 'ARM': - l += [KconfigCheck('security_policy', 'kspp', 'SECURITY', 'y')] # and choose your favourite LSM + l += [KconfigCheck('security_policy', 'kspp', 'SECURITY', 'y')] l += [KconfigCheck('security_policy', 'kspp', 'SECURITY_YAMA', 'y')] l += [KconfigCheck('security_policy', 'kspp', 'SECURITY_LANDLOCK', 'y')] l += [KconfigCheck('security_policy', 'kspp', 'SECURITY_SELINUX_DISABLE', 'is not set')] @@ -263,6 +230,10 @@ def add_kconfig_checks(l, arch): l += [KconfigCheck('security_policy', 'kspp', 'SECURITY_LOCKDOWN_LSM_EARLY', 'y')] l += [KconfigCheck('security_policy', 'kspp', 'LOCK_DOWN_KERNEL_FORCE_CONFIDENTIALITY', 'y')] l += [KconfigCheck('security_policy', 'kspp', 'SECURITY_WRITABLE_HOOKS', 'is not set')] # refers to SECURITY_SELINUX_DISABLE + l += [OR(KconfigCheck('security_policy', 'my', 'SECURITY_SELINUX', 'y'), + KconfigCheck('security_policy', 'my', 'SECURITY_APPARMOR', 'y'), + KconfigCheck('security_policy', 'my', 'SECURITY_SMACK', 'y'), + KconfigCheck('security_policy', 'my', 'SECURITY_TOMOYO', 'y'))] # one of major LSMs implementing MAC # 'cut_attack_surface', 'defconfig' l += [KconfigCheck('cut_attack_surface', 'defconfig', 'SECCOMP', 'y')] @@ -280,7 +251,6 @@ def add_kconfig_checks(l, arch): 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('cut_attack_surface', 'kspp', 'COMPAT_VDSO', 'is not set')] l += [KconfigCheck('cut_attack_surface', 'kspp', 'BINFMT_MISC', 'is not set')] l += [KconfigCheck('cut_attack_surface', 'kspp', 'INET_DIAG', 'is not set')] l += [KconfigCheck('cut_attack_surface', 'kspp', 'KEXEC', 'is not set')] # refers to LOCKDOWN @@ -300,8 +270,10 @@ def add_kconfig_checks(l, arch): devmem_not_set)] # refers to LOCKDOWN l += [AND(KconfigCheck('cut_attack_surface', 'kspp', 'LDISC_AUTOLOAD', 'is not set'), KconfigCheck('cut_attack_surface', 'kspp', 'LDISC_AUTOLOAD', 'is present'))] - if arch == 'X86_64': - l += [KconfigCheck('cut_attack_surface', 'kspp', 'LEGACY_VSYSCALL_NONE', 'y')] # 'vsyscall=none' + if arch in ('X86_64', 'X86_32'): + 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 == 'ARM': l += [OR(KconfigCheck('cut_attack_surface', 'kspp', 'STRICT_DEVMEM', 'y'), devmem_not_set)] # refers to LOCKDOWN @@ -360,7 +332,6 @@ def add_kconfig_checks(l, arch): l += [KconfigCheck('cut_attack_surface', 'clipos', 'STAGING', 'is not set')] l += [KconfigCheck('cut_attack_surface', 'clipos', 'KSM', 'is not set')] # to prevent FLUSH+RELOAD attack l += [KconfigCheck('cut_attack_surface', 'clipos', 'KALLSYMS', 'is not set')] - l += [KconfigCheck('cut_attack_surface', 'clipos', 'X86_VSYSCALL_EMULATION', 'is not set')] l += [KconfigCheck('cut_attack_surface', 'clipos', 'MAGIC_SYSRQ', 'is not set')] l += [KconfigCheck('cut_attack_surface', 'clipos', 'KEXEC_FILE', 'is not set')] # refers to LOCKDOWN (permissive) l += [KconfigCheck('cut_attack_surface', 'clipos', 'USER_NS', 'is not set')] # user.max_user_namespaces=0 @@ -370,6 +341,11 @@ def add_kconfig_checks(l, arch): 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 @@ -378,6 +354,7 @@ def add_kconfig_checks(l, arch): l += [bpf_syscall_not_set] # refers to LOCKDOWN # 'cut_attack_surface', 'my' + l += [KconfigCheck('cut_attack_surface', 'my', 'LEGACY_TIOCSTI', 'is not set')] l += [KconfigCheck('cut_attack_surface', 'my', 'MMIOTRACE', 'is not set')] # refers to LOCKDOWN (permissive) l += [KconfigCheck('cut_attack_surface', 'my', 'LIVEPATCH', 'is not set')] l += [KconfigCheck('cut_attack_surface', 'my', 'IP_DCCP', 'is not set')] @@ -387,23 +364,18 @@ def add_kconfig_checks(l, arch): l += [KconfigCheck('cut_attack_surface', 'my', 'INPUT_EVBUG', 'is not set')] # Can be used as a keylogger l += [KconfigCheck('cut_attack_surface', 'my', 'KGDB', 'is not set')] l += [KconfigCheck('cut_attack_surface', 'my', 'AIO', 'is not set')] + l += [KconfigCheck('cut_attack_surface', 'my', 'CORESIGHT', 'is not set')] + 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)] # 'harden_userspace' - if arch in ('X86_64', 'ARM64', 'X86_32'): - 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'): - l += [KconfigCheck('harden_userspace', 'clipos', 'ARCH_MMAP_RND_BITS', '32')] - if arch in ('X86_32', 'ARM'): - l += [KconfigCheck('harden_userspace', 'my', 'ARCH_MMAP_RND_BITS', '16')] + l += [KconfigCheck('harden_userspace', 'my', 'ARCH_MMAP_RND_BITS', 'MAX')] # 'MAX' value is refined using ARCH_MMAP_RND_BITS_MAX def add_cmdline_checks(l, arch): @@ -439,41 +411,56 @@ def add_cmdline_checks(l, arch): 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', 'spectre_v2', 'is not off'), - CmdlineCheck('self_protection', 'defconfig', 'spectre_v2', 'is not set'))] + AND(CmdlineCheck('self_protection', 'kspp', 'mitigations', 'auto,nosmt'), + CmdlineCheck('self_protection', 'defconfig', 'spectre_v2', 'is not set')))] l += [OR(CmdlineCheck('self_protection', 'defconfig', 'spectre_v2_user', 'is not off'), - CmdlineCheck('self_protection', 'defconfig', 'spectre_v2_user', 'is not set'))] + AND(CmdlineCheck('self_protection', 'kspp', 'mitigations', 'auto,nosmt'), + CmdlineCheck('self_protection', 'defconfig', 'spectre_v2_user', 'is not set')))] l += [OR(CmdlineCheck('self_protection', 'defconfig', 'spec_store_bypass_disable', 'is not off'), - CmdlineCheck('self_protection', 'defconfig', 'spec_store_bypass_disable', 'is not set'))] + 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', 'l1tf', 'is not off'), - CmdlineCheck('self_protection', 'defconfig', 'l1tf', 'is not set'))] + AND(CmdlineCheck('self_protection', 'kspp', 'mitigations', 'auto,nosmt'), + CmdlineCheck('self_protection', 'defconfig', 'l1tf', 'is not set')))] l += [OR(CmdlineCheck('self_protection', 'defconfig', 'mds', 'is not off'), - CmdlineCheck('self_protection', 'defconfig', 'mds', 'is not set'))] + AND(CmdlineCheck('self_protection', 'kspp', 'mitigations', 'auto,nosmt'), + CmdlineCheck('self_protection', 'defconfig', 'mds', 'is not set')))] l += [OR(CmdlineCheck('self_protection', 'defconfig', 'tsx_async_abort', 'is not off'), - CmdlineCheck('self_protection', 'defconfig', 'tsx_async_abort', 'is not set'))] + AND(CmdlineCheck('self_protection', 'kspp', 'mitigations', 'auto,nosmt'), + CmdlineCheck('self_protection', 'defconfig', 'tsx_async_abort', 'is not set')))] l += [OR(CmdlineCheck('self_protection', 'defconfig', 'srbds', 'is not off'), - CmdlineCheck('self_protection', 'defconfig', 'srbds', 'is not set'))] + AND(CmdlineCheck('self_protection', 'kspp', 'mitigations', 'auto,nosmt'), + CmdlineCheck('self_protection', 'defconfig', 'srbds', 'is not set')))] l += [OR(CmdlineCheck('self_protection', 'defconfig', 'mmio_stale_data', 'is not off'), - CmdlineCheck('self_protection', 'defconfig', 'mmio_stale_data', 'is not set'))] + AND(CmdlineCheck('self_protection', 'kspp', 'mitigations', 'auto,nosmt'), + CmdlineCheck('self_protection', 'defconfig', 'mmio_stale_data', 'is not set')))] l += [OR(CmdlineCheck('self_protection', 'defconfig', 'retbleed', 'is not off'), - CmdlineCheck('self_protection', 'defconfig', 'retbleed', 'is not set'))] + AND(CmdlineCheck('self_protection', 'kspp', 'mitigations', 'auto,nosmt'), + CmdlineCheck('self_protection', 'defconfig', 'retbleed', 'is not set')))] l += [OR(CmdlineCheck('self_protection', 'defconfig', 'kpti', 'is not off'), - CmdlineCheck('self_protection', 'defconfig', 'kpti', 'is not set'))] - l += [OR(CmdlineCheck('self_protection', 'defconfig', 'kvm.nx_huge_pages', 'is not off'), - CmdlineCheck('self_protection', 'defconfig', 'kvm.nx_huge_pages', 'is not set'))] + AND(CmdlineCheck('self_protection', 'kspp', 'mitigations', 'auto,nosmt'), + CmdlineCheck('self_protection', 'defconfig', 'kpti', 'is not set')))] if arch == 'ARM64': l += [OR(CmdlineCheck('self_protection', 'defconfig', 'ssbd', 'kernel'), CmdlineCheck('self_protection', 'my', 'ssbd', 'force-on'), - CmdlineCheck('self_protection', 'defconfig', 'ssbd', 'is not set'))] + AND(CmdlineCheck('self_protection', 'kspp', 'mitigations', 'auto,nosmt'), + CmdlineCheck('self_protection', 'defconfig', 'ssbd', 'is not set')))] 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'), + l += [OR(CmdlineCheck('self_protection', 'defconfig', 'rodata', 'on'), 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', '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 += [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'), + CmdlineCheck('self_protection', 'kspp', 'slub_merge', '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')))] @@ -483,10 +470,6 @@ def add_cmdline_checks(l, arch): 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', 'is present'), - AND(KconfigCheck('self_protection', 'clipos', 'SLAB_MERGE_DEFAULT', 'is not set'), - CmdlineCheck('self_protection', 'kspp', 'slab_merge', 'is not set'), - CmdlineCheck('self_protection', 'clipos', 'slub_merge', 'is not set')))] 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')))] @@ -523,8 +506,21 @@ def add_cmdline_checks(l, arch): # 'cut_attack_surface', 'kspp' if arch == 'X86_64': l += [OR(CmdlineCheck('cut_attack_surface', 'kspp', 'vsyscall', 'none'), + KconfigCheck('cut_attack_surface', 'clipos', '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'), + CmdlineCheck('cut_attack_surface', 'my', 'vdso32', '0'), + AND(KconfigCheck('cut_attack_surface', 'kspp', 'COMPAT_VDSO', 'is not set'), + CmdlineCheck('cut_attack_surface', 'my', 'vdso32', 'is not set')))] # the vdso32 parameter must not be 2 + if arch == 'X86_32': + l += [OR(CmdlineCheck('cut_attack_surface', 'my', 'vdso32', '1'), + CmdlineCheck('cut_attack_surface', 'my', 'vdso', '1'), + CmdlineCheck('cut_attack_surface', 'my', 'vdso32', '0'), + CmdlineCheck('cut_attack_surface', 'my', 'vdso', '0'), + AND(KconfigCheck('cut_attack_surface', 'kspp', 'COMPAT_VDSO', 'is not set'), + CmdlineCheck('cut_attack_surface', 'my', 'vdso32', 'is not set'), + CmdlineCheck('cut_attack_surface', 'my', 'vdso', 'is not set')))] # the vdso and vdso32 parameters must not be 2 # 'cut_attack_surface', 'grsec' # The cmdline checks compatible with the kconfig options disabled by grsecurity... @@ -534,55 +530,78 @@ def add_cmdline_checks(l, arch): # 'cut_attack_surface', 'my' l += [CmdlineCheck('cut_attack_surface', 'my', 'sysrq_always_enabled', 'is not set')] + # 'harden_userspace' + l += [CmdlineCheck('harden_userspace', 'defconfig', 'norandmaps', 'is not set')] + + +no_kstrtobool_options = [ + 'debugfs', # See debugfs_kernel() in fs/debugfs/inode.c + 'mitigations', # See mitigations_parse_cmdline() in kernel/cpu.c + '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 + '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 + 'tsx_async_abort', # See tsx_async_abort_parse_cmdline() in arch/x86/kernel/cpu/bugs.c + 'srbds', # See srbds_parse_cmdline() in arch/x86/kernel/cpu/bugs.c + 'mmio_stale_data', # See mmio_stale_data_parse_cmdline() in arch/x86/kernel/cpu/bugs.c + '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 + '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 + 'vdso32', # See vdso32_setup() in arch/x86/entry/vdso/vdso32-setup.c + 'vdso', # See vdso32_setup() in arch/x86/entry/vdso/vdso32-setup.c + 'tsx' # See tsx_init() in arch/x86/kernel/cpu/tsx.c +] + 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 == 'debugfs': - # See debugfs_kernel() in fs/debugfs/inode.c - return value - if option == 'mitigations': - # See mitigations_parse_cmdline() in kernel/cpu.c - return value - if option == 'pti': - # See pti_check_boottime_disable() in arch/x86/mm/pti.c - return value - if option == 'spectre_v2': - # See spectre_v2_parse_cmdline() in arch/x86/kernel/cpu/bugs.c - return value - if option == 'spectre_v2_user': - # See spectre_v2_parse_user_cmdline() in arch/x86/kernel/cpu/bugs.c - return value - if option == 'spec_store_bypass_disable': - # See ssb_parse_cmdline() in arch/x86/kernel/cpu/bugs.c - return value - if option == 'l1tf': - # See l1tf_cmdline() in arch/x86/kernel/cpu/bugs.c - return value - if option == 'mds': - # See mds_cmdline() in arch/x86/kernel/cpu/bugs.c - return value - if option == 'tsx_async_abort': - # See tsx_async_abort_parse_cmdline() in arch/x86/kernel/cpu/bugs.c - return value - if option == 'srbds': - # See srbds_parse_cmdline() in arch/x86/kernel/cpu/bugs.c - return value - if option == 'mmio_stale_data': - # See mmio_stale_data_parse_cmdline() in arch/x86/kernel/cpu/bugs.c - return value - if option == 'retbleed': - # See retbleed_parse_cmdline() in arch/x86/kernel/cpu/bugs.c - return value - if option == 'tsx': - # See tsx_init() in arch/x86/kernel/cpu/tsx.c + if option in no_kstrtobool_options: return value # Implement a limited part of the kstrtobool() logic - if value in ('1', 'on', 'On', 'ON', 'y', 'Y', 'yes', 'Yes', 'YES'): + if value.lower() in ('1', 'on', 'y', 'yes', 't', 'true'): return '1' - if value in ('0', 'off', 'Off', 'OFF', 'n', 'N', 'no', 'No', 'NO'): + if value.lower() in ('0', 'off', 'n', 'no', 'f', 'false'): return '0' # Preserve unique values return value + + +# def add_sysctl_checks(l, arch): +# TODO: draft of security hardening sysctls: +# kernel.kptr_restrict=2 (or 1?) +# kernel.dmesg_restrict=1 (also see the kconfig option) +# kernel.perf_event_paranoid=2 (or 3 with a custom patch, see https://lwn.net/Articles/696216/) +# kernel.kexec_load_disabled=1 +# kernel.yama.ptrace_scope=3 +# user.max_user_namespaces=0 (for Debian, also see kernel.unprivileged_userns_clone) +# what about bpf_jit_enable? +# kernel.unprivileged_bpf_disabled=1 +# net.core.bpf_jit_harden=2 +# 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 +# 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) +# kernel.oops_limit (think about a proper value) +# kernel.warn_limit (think about a proper value) +# net.ipv4.tcp_syncookies=1 (?)