There are plenty of Linux kernel hardening config options. A lot of them are not enabled by the major distros. We have to enable these options ourselves to make our systems more secure.
But nobody likes checking configs manually. So let the computers do their job!
kconfig-hardened-check.py helps me to check the Linux kernel Kconfig option list
against my hardening preferences for x86_64, which are based on the
KSPP recommended settings and last public grsecurity patch (options
which they disable).
Please don't cry if my Python code looks like C. I'm just a kernel developer.
TODO: add hardening preferences for ARM.
#./kconfig-hardened-check.py
usage: kconfig-hardened-check.py [-h] [-p] [-c CONFIG] [--debug]
Checks the hardening options in the Linux kernel config
optional arguments:
-h, --help show this help message and exit
-p, --print print hardening preferences
-c CONFIG, --config CONFIG
check the config_file against these preferences
--debug enable internal debug mode
#./kconfig-hardened-check.py -c config_files/ubuntu-bionic-generic.config
[+] Checking "config_files/ubuntu-bionic-generic.config" against hardening preferences...
option name | desired val | decision | reason || check result
===================================================================================================================
CONFIG_BUG | y | ubuntu18 | self_protection || OK
CONFIG_PAGE_TABLE_ISOLATION | y | ubuntu18 | self_protection || OK
CONFIG_RETPOLINE | y | ubuntu18 | self_protection || OK
CONFIG_X86_64 | y | ubuntu18 | self_protection || OK
CONFIG_X86_SMAP | y | ubuntu18 | self_protection || OK
CONFIG_X86_INTEL_UMIP | y | ubuntu18 | self_protection || OK
CONFIG_STRICT_KERNEL_RWX | y | ubuntu18 | self_protection || OK
CONFIG_DEBUG_WX | y | ubuntu18 | self_protection || OK
CONFIG_RANDOMIZE_BASE | y | ubuntu18 | self_protection || OK
CONFIG_RANDOMIZE_MEMORY | y | ubuntu18 | self_protection || OK
CONFIG_STACKPROTECTOR_STRONG | y | ubuntu18 | self_protection ||CONFIG_CC_STACKPROTECTOR_STRONG: OK ("y")
CONFIG_VMAP_STACK | y | ubuntu18 | self_protection || OK
CONFIG_THREAD_INFO_IN_TASK | y | ubuntu18 | self_protection || OK
CONFIG_SCHED_STACK_END_CHECK | y | ubuntu18 | self_protection || OK
CONFIG_SLUB_DEBUG | y | ubuntu18 | self_protection || OK
CONFIG_SLAB_FREELIST_HARDENED | y | ubuntu18 | self_protection || OK
CONFIG_SLAB_FREELIST_RANDOM | y | ubuntu18 | self_protection || OK
CONFIG_HARDENED_USERCOPY | y | ubuntu18 | self_protection || OK
CONFIG_FORTIFY_SOURCE | y | ubuntu18 | self_protection || OK
CONFIG_LOCK_DOWN_KERNEL | y | ubuntu18 | self_protection || OK
CONFIG_STRICT_MODULE_RWX | y | ubuntu18 | self_protection || OK
CONFIG_MODULE_SIG | y | ubuntu18 | self_protection || OK
CONFIG_MODULE_SIG_ALL | y | ubuntu18 | self_protection || OK
CONFIG_MODULE_SIG_SHA512 | y | ubuntu18 | self_protection || OK
CONFIG_SYN_COOKIES | y | ubuntu18 | self_protection || OK
CONFIG_DEFAULT_MMAP_MIN_ADDR | 65536 | ubuntu18 | self_protection || OK
CONFIG_BUG_ON_DATA_CORRUPTION | y | kspp | self_protection || FAIL: "is not set"
CONFIG_PAGE_POISONING | y | kspp | self_protection || FAIL: "is not set"
CONFIG_GCC_PLUGINS | y | kspp | self_protection || FAIL: "is not set"
CONFIG_GCC_PLUGIN_RANDSTRUCT | y | kspp | self_protection || FAIL: not found
CONFIG_GCC_PLUGIN_STRUCTLEAK | y | kspp | self_protection || FAIL: not found
CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL | y | kspp | self_protection || FAIL: not found
CONFIG_GCC_PLUGIN_LATENT_ENTROPY | y | kspp | self_protection || FAIL: not found
CONFIG_REFCOUNT_FULL | y | kspp | self_protection || FAIL: "is not set"
CONFIG_DEBUG_LIST | y | kspp | self_protection || FAIL: "is not set"
CONFIG_DEBUG_SG | y | kspp | self_protection || FAIL: "is not set"
CONFIG_DEBUG_CREDENTIALS | y | kspp | self_protection || FAIL: "is not set"
CONFIG_DEBUG_NOTIFIERS | y | kspp | self_protection || FAIL: "is not set"
CONFIG_MODULE_SIG_FORCE | y | kspp | self_protection || FAIL: "is not set"
CONFIG_HARDENED_USERCOPY_FALLBACK | is not set | kspp | self_protection || OK: not found
CONFIG_GCC_PLUGIN_STACKLEAK | y | my | self_protection || FAIL: not found
CONFIG_SLUB_DEBUG_ON | y | my | self_protection || FAIL: "is not set"
CONFIG_SECURITY_DMESG_RESTRICT | y | my | self_protection || FAIL: "is not set"
CONFIG_STATIC_USERMODEHELPER | y | my | self_protection || FAIL: "is not set"
CONFIG_SECURITY_LOADPIN | y | my | self_protection || FAIL: "is not set"
CONFIG_PAGE_POISONING_NO_SANITY | is not set | my | self_protection || OK: not found
CONFIG_PAGE_POISONING_ZERO | is not set | my | self_protection || OK: not found
CONFIG_SLAB_MERGE_DEFAULT | is not set | my | self_protection || FAIL: "y"
CONFIG_SECURITY | y | ubuntu18 | security_policy || OK
CONFIG_SECURITY_YAMA | y | ubuntu18 | security_policy || OK
CONFIG_SECURITY_SELINUX_DISABLE | is not set | ubuntu18 | security_policy || OK
CONFIG_SECCOMP | y | ubuntu18 | cut_attack_surface || OK
CONFIG_SECCOMP_FILTER | y | ubuntu18 | cut_attack_surface || OK
CONFIG_STRICT_DEVMEM | y | ubuntu18 | cut_attack_surface || OK
CONFIG_ACPI_CUSTOM_METHOD | is not set | ubuntu18 | cut_attack_surface || OK
CONFIG_COMPAT_BRK | is not set | ubuntu18 | cut_attack_surface || OK
CONFIG_DEVKMEM | is not set | ubuntu18 | cut_attack_surface || OK
CONFIG_COMPAT_VDSO | is not set | ubuntu18 | cut_attack_surface || OK
CONFIG_X86_PTDUMP | is not set | ubuntu18 | cut_attack_surface || OK
CONFIG_ZSMALLOC_STAT | is not set | ubuntu18 | cut_attack_surface || OK
CONFIG_PAGE_OWNER | is not set | ubuntu18 | cut_attack_surface || OK
CONFIG_DEBUG_KMEMLEAK | is not set | ubuntu18 | cut_attack_surface || OK
CONFIG_BINFMT_AOUT | is not set | ubuntu18 | cut_attack_surface || OK: not found
CONFIG_MMIOTRACE_TEST | is not set | ubuntu18 | cut_attack_surface || OK
CONFIG_IO_STRICT_DEVMEM | y | kspp | cut_attack_surface || FAIL: "is not set"
CONFIG_LEGACY_VSYSCALL_NONE | y | kspp | cut_attack_surface || FAIL: "is not set"
CONFIG_BINFMT_MISC | is not set | kspp | cut_attack_surface || FAIL: "m"
CONFIG_INET_DIAG | is not set | kspp | cut_attack_surface || FAIL: "m"
CONFIG_KEXEC | is not set | kspp | cut_attack_surface || FAIL: "y"
CONFIG_PROC_KCORE | is not set | kspp | cut_attack_surface || FAIL: "y"
CONFIG_LEGACY_PTYS | is not set | kspp | cut_attack_surface || FAIL: "y"
CONFIG_IA32_EMULATION | is not set | kspp | cut_attack_surface || FAIL: "y"
CONFIG_X86_X32 | is not set | kspp | cut_attack_surface || FAIL: "y"
CONFIG_MODIFY_LDT_SYSCALL | is not set | kspp | cut_attack_surface || FAIL: "y"
CONFIG_HIBERNATION | is not set | kspp | cut_attack_surface || FAIL: "y"
CONFIG_KPROBES | is not set |grsecurity| cut_attack_surface || FAIL: "y"
CONFIG_UPROBES | is not set |grsecurity| cut_attack_surface || FAIL: "y"
CONFIG_GENERIC_TRACER | is not set |grsecurity| cut_attack_surface || FAIL: "y"
CONFIG_PROC_VMCORE | is not set |grsecurity| cut_attack_surface || FAIL: "y"
CONFIG_PROC_PAGE_MONITOR | is not set |grsecurity| cut_attack_surface || FAIL: "y"
CONFIG_USELIB | is not set |grsecurity| cut_attack_surface || FAIL: "y"
CONFIG_CHECKPOINT_RESTORE | is not set |grsecurity| cut_attack_surface || FAIL: "y"
CONFIG_USERFAULTFD | is not set |grsecurity| cut_attack_surface || FAIL: "y"
CONFIG_HWPOISON_INJECT | is not set |grsecurity| cut_attack_surface || FAIL: "m"
CONFIG_MEM_SOFT_DIRTY | is not set |grsecurity| cut_attack_surface || FAIL: "y"
CONFIG_DEVPORT | is not set |grsecurity| cut_attack_surface || FAIL: "y"
CONFIG_DEBUG_FS | is not set |grsecurity| cut_attack_surface || FAIL: "y"
CONFIG_NOTIFIER_ERROR_INJECTION | is not set |grsecurity| cut_attack_surface || FAIL: "m"
CONFIG_ACPI_TABLE_UPGRADE | is not set | lockdown | cut_attack_surface || FAIL: "y"
CONFIG_ACPI_APEI_EINJ | is not set | lockdown | cut_attack_surface || FAIL: "m"
CONFIG_PROFILING | is not set | lockdown | cut_attack_surface || FAIL: "y"
CONFIG_BPF_SYSCALL | is not set | lockdown | cut_attack_surface || FAIL: "y"
CONFIG_MMIOTRACE | is not set | my | cut_attack_surface || FAIL: "y"
CONFIG_KEXEC_FILE | is not set | my | cut_attack_surface || FAIL: "y"
CONFIG_LIVEPATCH | is not set | my | cut_attack_surface || FAIL: "y"
CONFIG_USER_NS | is not set | my | cut_attack_surface || FAIL: "y"
CONFIG_IP_DCCP | is not set | my | cut_attack_surface || FAIL: "m"
CONFIG_IP_SCTP | is not set | my | cut_attack_surface || FAIL: "m"
CONFIG_FTRACE | is not set | my | cut_attack_surface || FAIL: "y"
CONFIG_BPF_JIT | is not set | my | cut_attack_surface || FAIL: "y"
CONFIG_ARCH_MMAP_RND_BITS | 32 | my |userspace_protection|| FAIL: "28"
[-] config check is NOT PASSED: 56 errors
N.B. If CONFIG_GCC_PLUGIN* options are automatically disabled during your kernel compilation,
that means that your gcc doesn't support plugins. For example, if you have gcc-7 on Ubuntu,
try to install gcc-7-plugin-dev package, it should help.
Go and fix them all!
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