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
Please don't cry if my Python code looks like C. I'm just a kernel developer.
#./kconfig-hardened-check.py
Usage: ./kconfig-hardened-check.py [-p | -c <config_file>]
-p, --print
print hardening preferences
-c <config_file>, --config=<config_file>
check the config_file against these preferences
./kconfig-hardened-check.py -c ubuntu-bionic-generic.config
[+] Checking "ubuntu-bionic-generic.config" against hardening preferences...
option name | desired val | decision | reason || check result
===========================================================================================================
CONFIG_FORTIFY_SOURCE | y | ubuntu18 | self_protection || OK
CONFIG_SLAB_FREELIST_HARDENED | y | ubuntu18 | self_protection || OK
CONFIG_PAGE_TABLE_ISOLATION | y | ubuntu18 | self_protection || OK
CONFIG_SLAB_FREELIST_RANDOM | y | ubuntu18 | self_protection || OK
CONFIG_RANDOMIZE_BASE | y | ubuntu18 | self_protection || OK
CONFIG_STRICT_KERNEL_RWX | y | ubuntu18 | self_protection || OK
CONFIG_STRICT_MODULE_RWX | y | ubuntu18 | self_protection || OK
CONFIG_DEBUG_WX | y | ubuntu18 | self_protection || OK
CONFIG_STRICT_DEVMEM | y | ubuntu18 | self_protection || OK
CONFIG_RETPOLINE | y | ubuntu18 | self_protection || OK
CONFIG_HARDENED_USERCOPY | y | ubuntu18 | self_protection || OK
CONFIG_VMAP_STACK | y | ubuntu18 | self_protection || OK
CONFIG_THREAD_INFO_IN_TASK | y | ubuntu18 | self_protection || OK
CONFIG_RANDOMIZE_BASE | y | ubuntu18 | self_protection || OK
CONFIG_RANDOMIZE_MEMORY | y | ubuntu18 | self_protection || OK
CONFIG_BUG | y | ubuntu18 | self_protection || OK
CONFIG_SYN_COOKIES | y | ubuntu18 | self_protection || OK
CONFIG_SECCOMP | y | ubuntu18 | self_protection || OK
CONFIG_SECCOMP_FILTER | y | ubuntu18 | self_protection || OK
CONFIG_SCHED_STACK_END_CHECK | 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_SLUB_DEBUG | y | ubuntu18 | self_protection || OK
CONFIG_CC_STACKPROTECTOR_STRONG | y | ubuntu18 | self_protection || OK
CONFIG_DEFAULT_MMAP_MIN_ADDR | 65536 | ubuntu18 | self_protection || OK
CONFIG_DEBUG_LIST | y | kspp | self_protection || FAIL: "is not set"
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_IO_STRICT_DEVMEM | y | kspp | self_protection || FAIL: "is not set"
CONFIG_REFCOUNT_FULL | 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 || FAIL: 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 | 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_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_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_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_MODIFY_LDT_SYSCALL | is not set | kspp | 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_NAMESPACES | is not set | my | cut_attack_surface || FAIL: "y"
CONFIG_IP_DCCP | is not set | my | cut_attack_surface || FAIL: "m"
CONFIG_FTRACE | is not set | my | cut_attack_surface || FAIL: "y"
CONFIG_KPROBES | is not set | my | cut_attack_surface || FAIL: "y"
CONFIG_PROFILING | is not set | my | cut_attack_surface || FAIL: "y"
CONFIG_UPROBES | is not set | my | cut_attack_surface || FAIL: "y"
CONFIG_BPF_JIT | is not set | my | cut_attack_surface || FAIL: "y"
CONFIG_BPF_SYSCALL | is not set | my | cut_attack_surface || FAIL: "y"
CONFIG_LKDTM | m | my | feature_test || FAIL: "is not set"
[-] config check is NOT PASSED: 36 errors
Go and fix them all!