X-Git-Url: https://jxself.org/git/?a=blobdiff_plain;f=kernel_hardening_checker%2Fchecks.py;h=fda5d46986f4f229c3e839f49f2107751005e907;hb=refs%2Fheads%2Fmaster;hp=f9b86d91c1d5d096bfc1e370b051f42c91ebc381;hpb=40b32a181e9657b2af3bd9ecb97c71c5fe855204;p=kconfig-hardened-check.git diff --git a/kernel_hardening_checker/checks.py b/kernel_hardening_checker/checks.py old mode 100644 new mode 100755 index f9b86d9..c2440cf --- a/kernel_hardening_checker/checks.py +++ b/kernel_hardening_checker/checks.py @@ -135,6 +135,9 @@ def add_kconfig_checks(l: List[ChecklistObjType], arch: str) -> None: l += [KconfigCheck('self_protection', 'defconfig', 'DEBUG_ALIGN_RODATA', 'y')] # 'self_protection', 'kspp' + l += [KconfigCheck('self_protection', 'kspp', 'LIST_HARDENED', 'y')] + l += [KconfigCheck('self_protection', 'kspp', 'RANDOM_KMALLOC_CACHES', 'y')] + l += [KconfigCheck('self_protection', 'kspp', 'SLAB_MERGE_DEFAULT', 'is not set')] l += [KconfigCheck('self_protection', 'kspp', 'PAGE_TABLE_CHECK', 'y')] l += [KconfigCheck('self_protection', 'kspp', 'PAGE_TABLE_CHECK_ENFORCED', 'y')] l += [KconfigCheck('self_protection', 'kspp', 'BUG_ON_DATA_CORRUPTION', 'y')] @@ -163,14 +166,14 @@ def add_kconfig_checks(l: List[ChecklistObjType], arch: str) -> None: vmap_stack_is_set)] kfence_is_set = KconfigCheck('self_protection', 'kspp', 'KFENCE', 'y') l += [kfence_is_set] - l += [AND(KconfigCheck('self_protection', 'a13xp0p0v', 'KFENCE_SAMPLE_INTERVAL', 'is not off'), + l += [AND(KconfigCheck('self_protection', 'kspp', '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 += [AND(KconfigCheck('self_protection', 'kspp', 'RANDSTRUCT_PERFORMANCE', 'is not set'), - KconfigCheck('self_protection', 'kspp', 'GCC_PLUGIN_RANDSTRUCT_PERFORMANCE', 'is not set'), - randstruct_is_set)] +# l += [AND(KconfigCheck('self_protection', 'kspp', 'RANDSTRUCT_PERFORMANCE', 'is not set'), +# KconfigCheck('self_protection', 'kspp', 'GCC_PLUGIN_RANDSTRUCT_PERFORMANCE', 'is not set'), +# randstruct_is_set)] # Comment this out for now: KSPP has revoked this recommendation 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'), @@ -263,13 +266,6 @@ def add_kconfig_checks(l: List[ChecklistObjType], arch: str) -> None: l += [AND(KconfigCheck('self_protection', 'kspp', 'INTEL_IOMMU', 'y'), iommu_support_is_set)] - # 'self_protection', 'clipos' - l += [KconfigCheck('self_protection', 'clipos', 'SLAB_MERGE_DEFAULT', 'is not set')] - - # 'self_protection', 'a13xp0p0v' - l += [KconfigCheck('self_protection', 'a13xp0p0v', 'LIST_HARDENED', 'y')] - l += [KconfigCheck('self_protection', 'a13xp0p0v', 'RANDOM_KMALLOC_CACHES', 'y')] - # 'security_policy' if arch in ('X86_64', 'ARM64', 'X86_32'): l += [KconfigCheck('security_policy', 'defconfig', 'SECURITY', 'y')] @@ -281,7 +277,7 @@ def add_kconfig_checks(l: List[ChecklistObjType], arch: str) -> None: l += [KconfigCheck('security_policy', 'kspp', 'SECURITY_SELINUX_BOOTPARAM', 'is not set')] l += [KconfigCheck('security_policy', 'kspp', 'SECURITY_SELINUX_DEVELOP', 'is not set')] l += [KconfigCheck('security_policy', 'kspp', 'SECURITY_WRITABLE_HOOKS', 'is not set')] # refers to SECURITY_SELINUX_DISABLE - l += [KconfigCheck('security_policy', 'a13xp0p0v', 'SECURITY_SELINUX_DEBUG', 'is not set')] + l += [KconfigCheck('security_policy', 'kspp', 'SECURITY_SELINUX_DEBUG', 'is not set')] l += [OR(KconfigCheck('security_policy', 'a13xp0p0v', 'SECURITY_SELINUX', 'y'), KconfigCheck('security_policy', 'a13xp0p0v', 'SECURITY_APPARMOR', 'y'), KconfigCheck('security_policy', 'a13xp0p0v', 'SECURITY_SMACK', 'y'), @@ -320,6 +316,7 @@ def add_kconfig_checks(l: List[ChecklistObjType], arch: str) -> None: l += [KconfigCheck('cut_attack_surface', 'kspp', 'OABI_COMPAT', 'is not set')] l += [KconfigCheck('cut_attack_surface', 'kspp', 'X86_MSR', 'is not set')] # refers to LOCKDOWN l += [KconfigCheck('cut_attack_surface', 'kspp', 'LEGACY_TIOCSTI', 'is not set')] + l += [KconfigCheck('cut_attack_surface', 'kspp', 'MODULE_FORCE_LOAD', 'is not set')] l += [modules_not_set] l += [devmem_not_set] l += [OR(KconfigCheck('cut_attack_surface', 'kspp', 'IO_STRICT_DEVMEM', 'y'), @@ -393,7 +390,6 @@ def add_kconfig_checks(l: List[ChecklistObjType], arch: str) -> None: 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', '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 l += [KconfigCheck('cut_attack_surface', 'clipos', 'X86_CPUID', 'is not set')] @@ -402,6 +398,8 @@ def add_kconfig_checks(l: List[ChecklistObjType], arch: str) -> None: l += [KconfigCheck('cut_attack_surface', 'clipos', 'EFI_CUSTOM_SSDT_OVERLAYS', 'is not set')] l += [KconfigCheck('cut_attack_surface', 'clipos', 'AIO', 'is not set')] # l += [KconfigCheck('cut_attack_surface', 'clipos', 'IKCONFIG', 'is not set')] # no, IKCONFIG is needed for this check :) + l += [OR(KconfigCheck('cut_attack_surface', 'clipos', 'MAGIC_SYSRQ', 'is not set'), + KconfigCheck('cut_attack_surface', 'a13xp0p0v', 'MAGIC_SYSRQ_DEFAULT_ENABLE', '0x0'))] # 'cut_attack_surface', 'lockdown' l += [KconfigCheck('cut_attack_surface', 'lockdown', 'EFI_TEST', 'is not set')] # refers to LOCKDOWN @@ -420,11 +418,11 @@ def add_kconfig_checks(l: List[ChecklistObjType], arch: str) -> None: 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 += [OR(KconfigCheck('cut_attack_surface', 'a13xp0p0v', 'MAGIC_SYSRQ_SERIAL', 'is not set'), + KconfigCheck('cut_attack_surface', 'a13xp0p0v', 'MAGIC_SYSRQ_DEFAULT_ENABLE', '0x0'))] # 'harden_userspace' if arch == 'ARM64': @@ -435,7 +433,7 @@ def add_kconfig_checks(l: List[ChecklistObjType], arch: str) -> None: 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')] + l += [KconfigCheck('harden_userspace', 'kspp', 'X86_USER_SHADOW_STACK', 'y')] def add_cmdline_checks(l: List[ChecklistObjType], arch: str) -> None: @@ -535,6 +533,7 @@ def add_cmdline_checks(l: List[ChecklistObjType], arch: str) -> None: 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 += [CmdlineCheck('self_protection', 'kspp', 'cfi', 'kcfi')] 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'), @@ -677,10 +676,7 @@ def normalize_cmdline_options(option: str, value: str) -> str: # vm.mmap_min_addr has a good value # nosmt sysfs control file # 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 (?) def add_sysctl_checks(l: List[ChecklistObjType], _arch: StrOrNone) -> None: @@ -695,6 +691,12 @@ def add_sysctl_checks(l: List[ChecklistObjType], _arch: StrOrNone) -> None: l += [OR(SysctlCheck('self_protection', 'kspp', 'net.core.bpf_jit_harden', '2'), AND(KconfigCheck('-', '-', 'BPF_JIT', 'is not set'), have_kconfig))] + # Choosing a right value for 'kernel.oops_limit' and 'kernel.warn_limit' is not easy. + # A small value (e.g. 1, which is recommended by KSPP) allows easy DoS. + # A large value (e.g. 10000, which is default 'kernel.oops_limit') may miss the exploit attempt. + # Let's choose 100 as a reasonable compromise. + l += [SysctlCheck('self_protection', 'a13xp0p0v', 'kernel.oops_limit', '100')] + l += [SysctlCheck('self_protection', 'a13xp0p0v', 'kernel.warn_limit', '100')] 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/ @@ -714,10 +716,14 @@ def add_sysctl_checks(l: List[ChecklistObjType], _arch: StrOrNone) -> None: # At first, it disabled unprivileged userfaultfd, # and since v5.11 it enables unprivileged userfaultfd for user-mode only. - l += [OR(SysctlCheck('cut_attack_surface', 'clipos', 'kernel.modules_disabled', '1'), + l += [OR(SysctlCheck('cut_attack_surface', 'kspp', '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 += [OR(SysctlCheck('cut_attack_surface', 'a13xp0p0v', 'kernel.sysrq', '0'), + AND(KconfigCheck('cut_attack_surface', 'clipos', 'MAGIC_SYSRQ', 'is not set'), + have_kconfig))] + 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')]