X-Git-Url: https://jxself.org/git/?a=blobdiff_plain;ds=inline;f=README.md;h=93307f99e3e725ac21c7ec9c95aa117d81508eaa;hb=fa15cc9530d65565b379892b8449d4d760fa6610;hp=4a8f2ed4ca3783361927e8a13db6ebd35ae5984e;hpb=60a83b77a98aeb52dd1cb262febee0e15a99f302;p=kconfig-hardened-check.git
diff --git a/README.md b/README.md
index 4a8f2ed..93307f9 100644
--- a/README.md
+++ b/README.md
@@ -1,19 +1,47 @@
-# Kconfig hardened check
+# kernel-hardening-checker (formerly kconfig-hardened-check)
+
+[![GitHub tag (latest by date)](https://img.shields.io/github/v/tag/a13xp0p0v/kernel-hardening-checker?label=release)](https://github.com/a13xp0p0v/kernel-hardening-checker/tags)
+[![functional test](https://github.com/a13xp0p0v/kernel-hardening-checker/workflows/functional%20test/badge.svg)](https://github.com/a13xp0p0v/kernel-hardening-checker/actions/workflows/functional_test.yml)
+[![functional test coverage](https://codecov.io/gh/a13xp0p0v/kernel-hardening-checker/graph/badge.svg?flag=functional_test)](https://codecov.io/gh/a13xp0p0v/kernel-hardening-checker)
+[![engine unit-test](https://github.com/a13xp0p0v/kernel-hardening-checker/workflows/engine%20unit-test/badge.svg)](https://github.com/a13xp0p0v/kernel-hardening-checker/actions/workflows/engine_unit-test.yml)
+[![unit-test coverage](https://codecov.io/gh/a13xp0p0v/kernel-hardening-checker/graph/badge.svg?flag=engine_unit-test)](https://codecov.io/gh/a13xp0p0v/kernel-hardening-checker)
## Motivation
-There are plenty of Linux kernel hardening config options. A lot of them are
+There are plenty of security hardening options for the Linux kernel. 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, which are based on the
-[KSPP recommended settings][1] and last public [grsecurity][2] patch (options
-which they disable).
+__kernel-hardening-checker__ is a tool for checking the security hardening options of the Linux kernel. It supports checking:
+
+ - Kconfig options (compile-time)
+ - Kernel cmdline arguments (boot-time)
+ - Sysctl parameters (runtime)
+
+The security hardening recommendations are based on:
+
+ - [KSPP recommended settings][1]
+ - [CLIP OS kernel configuration][2]
+ - Last public [grsecurity][3] patch (options which they disable)
+ - [SECURITY_LOCKDOWN_LSM][5] patchset
+ - [Direct feedback from the Linux kernel maintainers][23]
+
+I also created the [__Linux Kernel Defence Map__][4], which is a graphical representation of the
+relationships between security hardening features and the corresponding vulnerability classes
+or exploitation techniques.
+
+__Attention!__ Changing Linux kernel security parameters may also affect system performance
+and functionality of userspace software. So for choosing these parameters, consider
+the threat model of your Linux-based information system and perform thorough testing
+of its typical workload.
+
+## Repositories
-Please don't cry if my Python code looks like C. I'm just a kernel developer.
+ - Main at GitHub
+ - Mirror at Codeberg:
+ - Mirror at GitFlic:
## Supported microarchitectures
@@ -22,144 +50,435 @@ Please don't cry if my Python code looks like C. I'm just a kernel developer.
- ARM64
- ARM
-## Script output examples
+TODO: RISC-V (issue [#56][22])
+
+## Installation
+
+You can install the package:
+
+```
+pip install git+https://github.com/a13xp0p0v/kernel-hardening-checker
+```
+
+or simply run `./bin/kernel-hardening-checker` from the cloned repository.
-### Usage
+Some Linux distributions also provide `kernel-hardening-checker` as a package.
+
+## Usage
```
-#usage: kconfig-hardened-check.py [-h] [-p {X86_64,X86_32,ARM64,ARM}]
- [-c CONFIG] [--debug]
+usage: kernel-hardening-checker [-h] [--version] [-m {verbose,json,show_ok,show_fail}]
+ [-c CONFIG] [-l CMDLINE] [-s SYSCTL]
+ [-p {X86_64,X86_32,ARM64,ARM}]
+ [-g {X86_64,X86_32,ARM64,ARM}]
-Checks the hardening options in the Linux kernel config
+A tool for checking the security hardening options of the Linux kernel
-optional arguments:
+options:
-h, --help show this help message and exit
- -p {X86_64,X86_32,ARM64,ARM}, --print {X86_64,X86_32,ARM64,ARM}
- print hardening preferences for selected architecture
+ --version show program's version number and exit
+ -m {verbose,json,show_ok,show_fail}, --mode {verbose,json,show_ok,show_fail}
+ choose the report mode
-c CONFIG, --config CONFIG
- check the config_file against these preferences
- --debug enable internal debug mode
+ check the security hardening options in the kernel Kconfig file
+ (also supports *.gz files)
+ -l CMDLINE, --cmdline CMDLINE
+ check the security hardening options in the kernel cmdline file
+ (contents of /proc/cmdline)
+ -s SYSCTL, --sysctl SYSCTL
+ check the security hardening options in the sysctl output file
+ (`sudo sysctl -a > file`)
+ -p {X86_64,X86_32,ARM64,ARM}, --print {X86_64,X86_32,ARM64,ARM}
+ print the security hardening recommendations for the selected
+ microarchitecture
+ -g {X86_64,X86_32,ARM64,ARM}, --generate {X86_64,X86_32,ARM64,ARM}
+ generate a Kconfig fragment with the security hardening options
+ for the selected microarchitecture
+```
+## Output modes
+
+ - no `-m` argument for the default output mode (see the example below)
+ - `-m verbose` for printing additional info:
+ - config options without a corresponding check
+ - internals of complex checks with AND/OR, like this:
+```
+-------------------------------------------------------------------------------------------
+ <<< OR >>>
+CONFIG_STRICT_DEVMEM |kconfig| y |defconfig |cut_attack_surface
+CONFIG_DEVMEM |kconfig| is not set | kspp |cut_attack_surface
+-------------------------------------------------------------------------------------------
```
+ - `-m show_fail` for showing only the failed checks
+ - `-m show_ok` for showing only the successful checks
+ - `-m json` for printing the results in JSON format (for combining `kernel-hardening-checker` with other tools)
-### Script output for `Ubuntu 18.04 (Bionic Beaver)` kernel config
+## Example output for `Fedora 38` kernel configuration
```
-#./kconfig-hardened-check.py -c config_files/distros/ubuntu-bionic-generic.config
-[+] Trying to detect architecture in "config_files/distros/ubuntu-bionic-generic.config"...
-[+] Detected architecture: X86_64
-[+] Checking "config_files/distros/ubuntu-bionic-generic.config" against hardening preferences...
- option name | desired val | decision | reason || check result
- ===================================================================================================================
- CONFIG_BUG | y |defconfig | self_protection || OK
- CONFIG_STRICT_KERNEL_RWX | y |defconfig | self_protection || OK
- CONFIG_STACKPROTECTOR_STRONG | y |defconfig | self_protection ||CONFIG_CC_STACKPROTECTOR_STRONG: OK ("y")
- CONFIG_SLUB_DEBUG | y |defconfig | self_protection || OK
- CONFIG_STRICT_MODULE_RWX | y |defconfig | self_protection || OK
- CONFIG_PAGE_TABLE_ISOLATION | y |defconfig | self_protection || OK
- CONFIG_RANDOMIZE_MEMORY | y |defconfig | self_protection || OK
- CONFIG_RANDOMIZE_BASE | y |defconfig | self_protection || OK
- CONFIG_RETPOLINE | y |defconfig | self_protection || OK
- CONFIG_X86_SMAP | y |defconfig | self_protection || OK
- CONFIG_X86_INTEL_UMIP | y |defconfig | self_protection || OK
- CONFIG_SYN_COOKIES | y |defconfig | self_protection || OK
- CONFIG_VMAP_STACK | y |defconfig | self_protection || OK
- CONFIG_THREAD_INFO_IN_TASK | y |defconfig | self_protection || OK
- CONFIG_BUG_ON_DATA_CORRUPTION | y | kspp | self_protection || FAIL: "is not set"
- CONFIG_DEBUG_WX | y | kspp | self_protection || OK
- CONFIG_SCHED_STACK_END_CHECK | y | kspp | self_protection || OK
- CONFIG_PAGE_POISONING | y | kspp | self_protection || FAIL: "is not set"
- CONFIG_SLAB_FREELIST_HARDENED | y | kspp | self_protection || OK
- CONFIG_SLAB_FREELIST_RANDOM | y | kspp | self_protection || OK
- CONFIG_HARDENED_USERCOPY | y | kspp | self_protection || OK
- CONFIG_HARDENED_USERCOPY_FALLBACK | is not set | kspp | self_protection || OK: not found
- CONFIG_FORTIFY_SOURCE | y | kspp | self_protection || OK
- 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_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 | y | kspp | self_protection || OK
- CONFIG_MODULE_SIG_ALL | y | kspp | self_protection || OK
- CONFIG_MODULE_SIG_SHA512 | y | kspp | self_protection || OK
- CONFIG_MODULE_SIG_FORCE | y | kspp | self_protection || FAIL: "is not set"
- CONFIG_DEFAULT_MMAP_MIN_ADDR | 65536 | kspp | self_protection || OK
- CONFIG_REFCOUNT_FULL | y | kspp | self_protection || FAIL: "is not set"
- CONFIG_GCC_PLUGIN_STACKLEAK | y | my | self_protection || FAIL: not found
- CONFIG_LOCK_DOWN_KERNEL | y | my | self_protection || OK
- 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 |defconfig | security_policy || OK
- CONFIG_SECURITY_YAMA | y | kspp | security_policy || OK
- CONFIG_SECURITY_SELINUX_DISABLE | is not set | kspp | security_policy || OK
- CONFIG_SECCOMP | y |defconfig | cut_attack_surface || OK
- CONFIG_SECCOMP_FILTER | y |defconfig | cut_attack_surface || OK
- CONFIG_STRICT_DEVMEM | y |defconfig | cut_attack_surface || OK
- CONFIG_IO_STRICT_DEVMEM | y | kspp | cut_attack_surface || FAIL: "is not set"
- CONFIG_ACPI_CUSTOM_METHOD | is not set | kspp | cut_attack_surface || OK
- CONFIG_COMPAT_BRK | is not set | kspp | cut_attack_surface || OK
- CONFIG_DEVKMEM | is not set | kspp | cut_attack_surface || OK
- CONFIG_COMPAT_VDSO | is not set | kspp | cut_attack_surface || OK
- 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_HIBERNATION | is not set | kspp | cut_attack_surface || FAIL: "y"
- CONFIG_LEGACY_VSYSCALL_NONE | y | kspp | cut_attack_surface || FAIL: "is not set"
- 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_X86_PTDUMP | is not set |grsecurity| cut_attack_surface || OK
- CONFIG_ZSMALLOC_STAT | is not set |grsecurity| cut_attack_surface || OK
- CONFIG_PAGE_OWNER | is not set |grsecurity| cut_attack_surface || OK
- CONFIG_DEBUG_KMEMLEAK | is not set |grsecurity| cut_attack_surface || OK
- CONFIG_BINFMT_AOUT | is not set |grsecurity| cut_attack_surface || OK: not found
- 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_TEST | is not set | lockdown | cut_attack_surface || OK
- 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
+$ ./bin/kernel-hardening-checker -c kernel_hardening_checker/config_files/distros/fedora_38.config -l /proc/cmdline -s kernel_hardening_checker/config_files/distros/example_sysctls.txt
+[+] Kconfig file to check: kernel_hardening_checker/config_files/distros/fedora_38.config
+[+] Kernel cmdline file to check: /proc/cmdline
+[+] Sysctl output file to check: kernel_hardening_checker/config_files/distros/example_sysctls.txt
+[+] Detected microarchitecture: X86_64
+[+] Detected kernel version: 6.3
+[+] Detected compiler: GCC 130101
+=========================================================================================================================
+ option name | type |desired val | decision | reason | check result
+=========================================================================================================================
+CONFIG_BUG |kconfig| y |defconfig | self_protection | OK
+CONFIG_SLUB_DEBUG |kconfig| y |defconfig | self_protection | OK
+CONFIG_THREAD_INFO_IN_TASK |kconfig| y |defconfig | self_protection | OK
+CONFIG_GCC_PLUGINS |kconfig| y |defconfig | self_protection | FAIL: "is not set"
+CONFIG_IOMMU_SUPPORT |kconfig| y |defconfig | self_protection | OK
+CONFIG_STACKPROTECTOR |kconfig| y |defconfig | self_protection | OK
+CONFIG_STACKPROTECTOR_STRONG |kconfig| y |defconfig | self_protection | OK
+CONFIG_STRICT_KERNEL_RWX |kconfig| y |defconfig | self_protection | OK
+CONFIG_STRICT_MODULE_RWX |kconfig| y |defconfig | self_protection | OK
+CONFIG_REFCOUNT_FULL |kconfig| y |defconfig | self_protection | OK: version >= 5.5
+CONFIG_RANDOMIZE_BASE |kconfig| y |defconfig | self_protection | OK
+CONFIG_VMAP_STACK |kconfig| y |defconfig | self_protection | OK
+CONFIG_DEBUG_WX |kconfig| y |defconfig | self_protection | OK
+CONFIG_WERROR |kconfig| y |defconfig | self_protection | FAIL: "is not set"
+CONFIG_X86_MCE |kconfig| y |defconfig | self_protection | OK
+CONFIG_X86_MCE_INTEL |kconfig| y |defconfig | self_protection | OK
+CONFIG_X86_MCE_AMD |kconfig| y |defconfig | self_protection | OK
+CONFIG_MICROCODE |kconfig| y |defconfig | self_protection | OK
+CONFIG_RETPOLINE |kconfig| y |defconfig | self_protection | OK
+CONFIG_SYN_COOKIES |kconfig| y |defconfig | self_protection | OK
+CONFIG_X86_SMAP |kconfig| y |defconfig | self_protection | OK: version >= 5.19
+CONFIG_X86_UMIP |kconfig| y |defconfig | self_protection | OK
+CONFIG_PAGE_TABLE_ISOLATION |kconfig| y |defconfig | self_protection | OK
+CONFIG_RANDOMIZE_MEMORY |kconfig| y |defconfig | self_protection | OK
+CONFIG_X86_KERNEL_IBT |kconfig| y |defconfig | self_protection | OK
+CONFIG_INTEL_IOMMU |kconfig| y |defconfig | self_protection | OK
+CONFIG_AMD_IOMMU |kconfig| y |defconfig | self_protection | OK
+CONFIG_BUG_ON_DATA_CORRUPTION |kconfig| y | kspp | self_protection | OK
+CONFIG_SCHED_STACK_END_CHECK |kconfig| y | kspp | self_protection | OK
+CONFIG_SLAB_FREELIST_HARDENED |kconfig| y | kspp | self_protection | OK
+CONFIG_SLAB_FREELIST_RANDOM |kconfig| y | kspp | self_protection | OK
+CONFIG_SHUFFLE_PAGE_ALLOCATOR |kconfig| y | kspp | self_protection | OK
+CONFIG_FORTIFY_SOURCE |kconfig| y | kspp | self_protection | OK
+CONFIG_DEBUG_LIST |kconfig| y | kspp | self_protection | OK
+CONFIG_DEBUG_VIRTUAL |kconfig| y | kspp | self_protection | FAIL: "is not set"
+CONFIG_DEBUG_SG |kconfig| y | kspp | self_protection | FAIL: "is not set"
+CONFIG_DEBUG_CREDENTIALS |kconfig| y | kspp | self_protection | FAIL: "is not set"
+CONFIG_DEBUG_NOTIFIERS |kconfig| y | kspp | self_protection | FAIL: "is not set"
+CONFIG_INIT_ON_ALLOC_DEFAULT_ON |kconfig| y | kspp | self_protection | FAIL: "is not set"
+CONFIG_KFENCE |kconfig| y | kspp | self_protection | OK
+CONFIG_ZERO_CALL_USED_REGS |kconfig| y | kspp | self_protection | FAIL: "is not set"
+CONFIG_HW_RANDOM_TPM |kconfig| y | kspp | self_protection | OK
+CONFIG_STATIC_USERMODEHELPER |kconfig| y | kspp | self_protection | FAIL: "is not set"
+CONFIG_RANDSTRUCT_FULL |kconfig| y | kspp | self_protection | FAIL: is not found
+CONFIG_RANDSTRUCT_PERFORMANCE |kconfig| is not set | kspp | self_protection | FAIL: CONFIG_RANDSTRUCT_FULL is not "y"
+CONFIG_HARDENED_USERCOPY |kconfig| y | kspp | self_protection | OK
+CONFIG_HARDENED_USERCOPY_FALLBACK |kconfig| is not set | kspp | self_protection | OK: is not found
+CONFIG_HARDENED_USERCOPY_PAGESPAN |kconfig| is not set | kspp | self_protection | OK: is not found
+CONFIG_GCC_PLUGIN_LATENT_ENTROPY |kconfig| y | kspp | self_protection | FAIL: CONFIG_GCC_PLUGINS is not "y"
+CONFIG_MODULE_SIG |kconfig| y | kspp | self_protection | OK
+CONFIG_MODULE_SIG_ALL |kconfig| y | kspp | self_protection | OK
+CONFIG_MODULE_SIG_SHA512 |kconfig| y | kspp | self_protection | OK
+CONFIG_MODULE_SIG_FORCE |kconfig| y | kspp | self_protection | FAIL: "is not set"
+CONFIG_INIT_STACK_ALL_ZERO |kconfig| y | kspp | self_protection | OK
+CONFIG_INIT_ON_FREE_DEFAULT_ON |kconfig| y | kspp | self_protection | FAIL: "is not set"
+CONFIG_EFI_DISABLE_PCI_DMA |kconfig| y | kspp | self_protection | FAIL: "is not set"
+CONFIG_RESET_ATTACK_MITIGATION |kconfig| y | kspp | self_protection | FAIL: "is not set"
+CONFIG_UBSAN_BOUNDS |kconfig| y | kspp | self_protection | FAIL: is not found
+CONFIG_UBSAN_LOCAL_BOUNDS |kconfig| y | kspp | self_protection | FAIL: is not found
+CONFIG_UBSAN_TRAP |kconfig| y | kspp | self_protection | FAIL: CONFIG_UBSAN_BOUNDS is not "y"
+CONFIG_UBSAN_SANITIZE_ALL |kconfig| y | kspp | self_protection | FAIL: CONFIG_UBSAN_BOUNDS is not "y"
+CONFIG_GCC_PLUGIN_STACKLEAK |kconfig| y | kspp | self_protection | FAIL: CONFIG_GCC_PLUGINS is not "y"
+CONFIG_STACKLEAK_METRICS |kconfig| is not set | kspp | self_protection | FAIL: CONFIG_GCC_PLUGINS is not "y"
+CONFIG_STACKLEAK_RUNTIME_DISABLE |kconfig| is not set | kspp | self_protection | FAIL: CONFIG_GCC_PLUGINS is not "y"
+CONFIG_RANDOMIZE_KSTACK_OFFSET_DEFAULT |kconfig| y | kspp | self_protection | OK
+CONFIG_CFI_CLANG |kconfig| y | kspp | self_protection | FAIL: is not found
+CONFIG_CFI_PERMISSIVE |kconfig| is not set | kspp | self_protection | FAIL: CONFIG_CFI_CLANG is not "y"
+CONFIG_SCHED_CORE |kconfig| y | kspp | self_protection | OK
+CONFIG_DEFAULT_MMAP_MIN_ADDR |kconfig| 65536 | kspp | self_protection | OK
+CONFIG_IOMMU_DEFAULT_DMA_STRICT |kconfig| y | kspp | self_protection | FAIL: "is not set"
+CONFIG_IOMMU_DEFAULT_PASSTHROUGH |kconfig| is not set | kspp | self_protection | OK
+CONFIG_INTEL_IOMMU_DEFAULT_ON |kconfig| y | kspp | self_protection | FAIL: "is not set"
+CONFIG_SLS |kconfig| y | kspp | self_protection | OK
+CONFIG_INTEL_IOMMU_SVM |kconfig| y | kspp | self_protection | OK
+CONFIG_AMD_IOMMU_V2 |kconfig| y | kspp | self_protection | FAIL: "m"
+CONFIG_SLAB_MERGE_DEFAULT |kconfig| is not set | clipos | self_protection | OK
+CONFIG_SECURITY |kconfig| y |defconfig | security_policy | OK
+CONFIG_SECURITY_YAMA |kconfig| y | kspp | security_policy | OK
+CONFIG_SECURITY_LANDLOCK |kconfig| y | kspp | security_policy | OK
+CONFIG_SECURITY_SELINUX_DISABLE |kconfig| is not set | kspp | security_policy | OK
+CONFIG_SECURITY_SELINUX_BOOTPARAM |kconfig| is not set | kspp | security_policy | FAIL: "y"
+CONFIG_SECURITY_SELINUX_DEVELOP |kconfig| is not set | kspp | security_policy | FAIL: "y"
+CONFIG_SECURITY_LOCKDOWN_LSM |kconfig| y | kspp | security_policy | OK
+CONFIG_SECURITY_LOCKDOWN_LSM_EARLY |kconfig| y | kspp | security_policy | OK
+CONFIG_LOCK_DOWN_KERNEL_FORCE_CONFIDENTIALITY|kconfig| y | kspp | security_policy | FAIL: "is not set"
+CONFIG_SECURITY_WRITABLE_HOOKS |kconfig| is not set | kspp | security_policy | OK: is not found
+CONFIG_SECURITY_SELINUX |kconfig| y | my | security_policy | OK
+CONFIG_SECCOMP |kconfig| y |defconfig |cut_attack_surface| OK
+CONFIG_SECCOMP_FILTER |kconfig| y |defconfig |cut_attack_surface| OK
+CONFIG_BPF_UNPRIV_DEFAULT_OFF |kconfig| y |defconfig |cut_attack_surface| OK
+CONFIG_STRICT_DEVMEM |kconfig| y |defconfig |cut_attack_surface| OK
+CONFIG_X86_INTEL_TSX_MODE_OFF |kconfig| y |defconfig |cut_attack_surface| OK
+CONFIG_SECURITY_DMESG_RESTRICT |kconfig| y | kspp |cut_attack_surface| FAIL: "is not set"
+CONFIG_ACPI_CUSTOM_METHOD |kconfig| is not set | kspp |cut_attack_surface| OK
+CONFIG_COMPAT_BRK |kconfig| is not set | kspp |cut_attack_surface| OK
+CONFIG_DEVKMEM |kconfig| is not set | kspp |cut_attack_surface| OK: is not found
+CONFIG_BINFMT_MISC |kconfig| is not set | kspp |cut_attack_surface| FAIL: "m"
+CONFIG_INET_DIAG |kconfig| is not set | kspp |cut_attack_surface| FAIL: "y"
+CONFIG_KEXEC |kconfig| is not set | kspp |cut_attack_surface| FAIL: "y"
+CONFIG_PROC_KCORE |kconfig| is not set | kspp |cut_attack_surface| FAIL: "y"
+CONFIG_LEGACY_PTYS |kconfig| is not set | kspp |cut_attack_surface| OK
+CONFIG_HIBERNATION |kconfig| is not set | kspp |cut_attack_surface| FAIL: "y"
+CONFIG_COMPAT |kconfig| is not set | kspp |cut_attack_surface| FAIL: "y"
+CONFIG_IA32_EMULATION |kconfig| is not set | kspp |cut_attack_surface| FAIL: "y"
+CONFIG_X86_X32 |kconfig| is not set | kspp |cut_attack_surface| OK: is not found
+CONFIG_X86_X32_ABI |kconfig| is not set | kspp |cut_attack_surface| OK
+CONFIG_MODIFY_LDT_SYSCALL |kconfig| is not set | kspp |cut_attack_surface| FAIL: "y"
+CONFIG_OABI_COMPAT |kconfig| is not set | kspp |cut_attack_surface| OK: is not found
+CONFIG_X86_MSR |kconfig| is not set | kspp |cut_attack_surface| FAIL: "y"
+CONFIG_MODULES |kconfig| is not set | kspp |cut_attack_surface| FAIL: "y"
+CONFIG_DEVMEM |kconfig| is not set | kspp |cut_attack_surface| FAIL: "y"
+CONFIG_IO_STRICT_DEVMEM |kconfig| y | kspp |cut_attack_surface| OK
+CONFIG_LDISC_AUTOLOAD |kconfig| is not set | kspp |cut_attack_surface| FAIL: "y"
+CONFIG_COMPAT_VDSO |kconfig| is not set | kspp |cut_attack_surface| OK
+CONFIG_ZSMALLOC_STAT |kconfig| is not set | grsec |cut_attack_surface| OK
+CONFIG_PAGE_OWNER |kconfig| is not set | grsec |cut_attack_surface| FAIL: "y"
+CONFIG_DEBUG_KMEMLEAK |kconfig| is not set | grsec |cut_attack_surface| OK
+CONFIG_BINFMT_AOUT |kconfig| is not set | grsec |cut_attack_surface| OK: is not found
+CONFIG_KPROBE_EVENTS |kconfig| is not set | grsec |cut_attack_surface| FAIL: "y"
+CONFIG_UPROBE_EVENTS |kconfig| is not set | grsec |cut_attack_surface| FAIL: "y"
+CONFIG_GENERIC_TRACER |kconfig| is not set | grsec |cut_attack_surface| FAIL: "y"
+CONFIG_FUNCTION_TRACER |kconfig| is not set | grsec |cut_attack_surface| FAIL: "y"
+CONFIG_STACK_TRACER |kconfig| is not set | grsec |cut_attack_surface| FAIL: "y"
+CONFIG_HIST_TRIGGERS |kconfig| is not set | grsec |cut_attack_surface| FAIL: "y"
+CONFIG_BLK_DEV_IO_TRACE |kconfig| is not set | grsec |cut_attack_surface| FAIL: "y"
+CONFIG_PROC_VMCORE |kconfig| is not set | grsec |cut_attack_surface| FAIL: "y"
+CONFIG_PROC_PAGE_MONITOR |kconfig| is not set | grsec |cut_attack_surface| FAIL: "y"
+CONFIG_USELIB |kconfig| is not set | grsec |cut_attack_surface| OK
+CONFIG_CHECKPOINT_RESTORE |kconfig| is not set | grsec |cut_attack_surface| FAIL: "y"
+CONFIG_USERFAULTFD |kconfig| is not set | grsec |cut_attack_surface| FAIL: "y"
+CONFIG_HWPOISON_INJECT |kconfig| is not set | grsec |cut_attack_surface| FAIL: "m"
+CONFIG_MEM_SOFT_DIRTY |kconfig| is not set | grsec |cut_attack_surface| FAIL: "y"
+CONFIG_DEVPORT |kconfig| is not set | grsec |cut_attack_surface| FAIL: "y"
+CONFIG_DEBUG_FS |kconfig| is not set | grsec |cut_attack_surface| FAIL: "y"
+CONFIG_NOTIFIER_ERROR_INJECTION |kconfig| is not set | grsec |cut_attack_surface| OK
+CONFIG_FAIL_FUTEX |kconfig| is not set | grsec |cut_attack_surface| OK: is not found
+CONFIG_PUNIT_ATOM_DEBUG |kconfig| is not set | grsec |cut_attack_surface| OK
+CONFIG_ACPI_CONFIGFS |kconfig| is not set | grsec |cut_attack_surface| OK
+CONFIG_EDAC_DEBUG |kconfig| is not set | grsec |cut_attack_surface| OK
+CONFIG_DRM_I915_DEBUG |kconfig| is not set | grsec |cut_attack_surface| OK: is not found
+CONFIG_BCACHE_CLOSURES_DEBUG |kconfig| is not set | grsec |cut_attack_surface| OK
+CONFIG_DVB_C8SECTPFE |kconfig| is not set | grsec |cut_attack_surface| OK: is not found
+CONFIG_MTD_SLRAM |kconfig| is not set | grsec |cut_attack_surface| OK
+CONFIG_MTD_PHRAM |kconfig| is not set | grsec |cut_attack_surface| OK
+CONFIG_IO_URING |kconfig| is not set | grsec |cut_attack_surface| FAIL: "y"
+CONFIG_KCMP |kconfig| is not set | grsec |cut_attack_surface| FAIL: "y"
+CONFIG_RSEQ |kconfig| is not set | grsec |cut_attack_surface| FAIL: "y"
+CONFIG_LATENCYTOP |kconfig| is not set | grsec |cut_attack_surface| FAIL: "y"
+CONFIG_KCOV |kconfig| is not set | grsec |cut_attack_surface| OK
+CONFIG_PROVIDE_OHCI1394_DMA_INIT |kconfig| is not set | grsec |cut_attack_surface| FAIL: "y"
+CONFIG_SUNRPC_DEBUG |kconfig| is not set | grsec |cut_attack_surface| FAIL: "y"
+CONFIG_PTDUMP_DEBUGFS |kconfig| is not set | grsec |cut_attack_surface| OK
+CONFIG_DRM_LEGACY |kconfig| is not set |maintainer|cut_attack_surface| OK
+CONFIG_FB |kconfig| is not set |maintainer|cut_attack_surface| FAIL: "y"
+CONFIG_VT |kconfig| is not set |maintainer|cut_attack_surface| FAIL: "y"
+CONFIG_BLK_DEV_FD |kconfig| is not set |maintainer|cut_attack_surface| FAIL: "m"
+CONFIG_BLK_DEV_FD_RAWCMD |kconfig| is not set |maintainer|cut_attack_surface| OK
+CONFIG_NOUVEAU_LEGACY_CTX_SUPPORT |kconfig| is not set |maintainer|cut_attack_surface| OK: is not found
+CONFIG_STAGING |kconfig| is not set | clipos |cut_attack_surface| FAIL: "y"
+CONFIG_KSM |kconfig| is not set | clipos |cut_attack_surface| FAIL: "y"
+CONFIG_KALLSYMS |kconfig| is not set | clipos |cut_attack_surface| FAIL: "y"
+CONFIG_MAGIC_SYSRQ |kconfig| is not set | clipos |cut_attack_surface| FAIL: "y"
+CONFIG_KEXEC_FILE |kconfig| is not set | clipos |cut_attack_surface| FAIL: "y"
+CONFIG_USER_NS |kconfig| is not set | clipos |cut_attack_surface| FAIL: "y"
+CONFIG_X86_CPUID |kconfig| is not set | clipos |cut_attack_surface| FAIL: "y"
+CONFIG_X86_IOPL_IOPERM |kconfig| is not set | clipos |cut_attack_surface| FAIL: "y"
+CONFIG_ACPI_TABLE_UPGRADE |kconfig| is not set | clipos |cut_attack_surface| FAIL: "y"
+CONFIG_EFI_CUSTOM_SSDT_OVERLAYS |kconfig| is not set | clipos |cut_attack_surface| FAIL: "y"
+CONFIG_COREDUMP |kconfig| is not set | clipos |cut_attack_surface| FAIL: "y"
+CONFIG_X86_VSYSCALL_EMULATION |kconfig| is not set | clipos |cut_attack_surface| FAIL: "y"
+CONFIG_EFI_TEST |kconfig| is not set | lockdown |cut_attack_surface| FAIL: "m"
+CONFIG_MMIOTRACE_TEST |kconfig| is not set | lockdown |cut_attack_surface| OK
+CONFIG_KPROBES |kconfig| is not set | lockdown |cut_attack_surface| FAIL: "y"
+CONFIG_BPF_SYSCALL |kconfig| is not set | lockdown |cut_attack_surface| FAIL: "y"
+CONFIG_LEGACY_TIOCSTI |kconfig| is not set | my |cut_attack_surface| OK
+CONFIG_MMIOTRACE |kconfig| is not set | my |cut_attack_surface| FAIL: "y"
+CONFIG_LIVEPATCH |kconfig| is not set | my |cut_attack_surface| FAIL: "y"
+CONFIG_IP_DCCP |kconfig| is not set | my |cut_attack_surface| OK
+CONFIG_IP_SCTP |kconfig| is not set | my |cut_attack_surface| FAIL: "m"
+CONFIG_FTRACE |kconfig| is not set | my |cut_attack_surface| FAIL: "y"
+CONFIG_VIDEO_VIVID |kconfig| is not set | my |cut_attack_surface| FAIL: "m"
+CONFIG_INPUT_EVBUG |kconfig| is not set | my |cut_attack_surface| OK
+CONFIG_KGDB |kconfig| is not set | my |cut_attack_surface| FAIL: "y"
+CONFIG_AIO |kconfig| is not set | my |cut_attack_surface| FAIL: "y"
+CONFIG_CORESIGHT |kconfig| is not set | my |cut_attack_surface| OK: is not found
+CONFIG_XFS_SUPPORT_V4 |kconfig| is not set | my |cut_attack_surface| FAIL: "y"
+CONFIG_TRIM_UNUSED_KSYMS |kconfig| y | my |cut_attack_surface| FAIL: is not found
+CONFIG_ARCH_MMAP_RND_BITS |kconfig| 32 | my | harden_userspace | FAIL: "28"
+nosmep |cmdline| is not set |defconfig | self_protection | OK: is not found
+nosmap |cmdline| is not set |defconfig | self_protection | OK: is not found
+nokaslr |cmdline| is not set |defconfig | self_protection | OK: is not found
+nopti |cmdline| is not set |defconfig | self_protection | OK: is not found
+nospectre_v1 |cmdline| is not set |defconfig | self_protection | OK: is not found
+nospectre_v2 |cmdline| is not set |defconfig | self_protection | OK: is not found
+nospectre_bhb |cmdline| is not set |defconfig | self_protection | OK: is not found
+nospec_store_bypass_disable |cmdline| is not set |defconfig | self_protection | OK: is not found
+arm64.nobti |cmdline| is not set |defconfig | self_protection | OK: is not found
+arm64.nopauth |cmdline| is not set |defconfig | self_protection | OK: is not found
+arm64.nomte |cmdline| is not set |defconfig | self_protection | OK: is not found
+spectre_v2 |cmdline| is not off |defconfig | self_protection | FAIL: is off, not found
+spectre_v2_user |cmdline| is not off |defconfig | self_protection | FAIL: is off, not found
+spec_store_bypass_disable |cmdline| is not off |defconfig | self_protection | FAIL: is off, not found
+l1tf |cmdline| is not off |defconfig | self_protection | FAIL: is off, not found
+mds |cmdline| is not off |defconfig | self_protection | FAIL: is off, not found
+tsx_async_abort |cmdline| is not off |defconfig | self_protection | FAIL: is off, not found
+srbds |cmdline| is not off |defconfig | self_protection | FAIL: is off, not found
+mmio_stale_data |cmdline| is not off |defconfig | self_protection | FAIL: is off, not found
+retbleed |cmdline| is not off |defconfig | self_protection | FAIL: is off, not found
+kpti |cmdline| is not off |defconfig | self_protection | FAIL: is off, not found
+rodata |cmdline| on |defconfig | self_protection | OK: rodata is not found
+nosmt |cmdline| is present | kspp | self_protection | FAIL: is not present
+mitigations |cmdline| auto,nosmt | kspp | self_protection | FAIL: is not found
+slab_merge |cmdline| is not set | kspp | self_protection | OK: is not found
+slub_merge |cmdline| is not set | kspp | self_protection | OK: is not found
+slab_nomerge |cmdline| is present | kspp | self_protection | OK: CONFIG_SLAB_MERGE_DEFAULT is "is not set"
+init_on_alloc |cmdline| 1 | kspp | self_protection | FAIL: is not found
+init_on_free |cmdline| 1 | kspp | self_protection | FAIL: is not found
+iommu.strict |cmdline| 1 | kspp | self_protection | FAIL: is not found
+iommu.passthrough |cmdline| 0 | kspp | self_protection | OK: CONFIG_IOMMU_DEFAULT_PASSTHROUGH is "is not set"
+hardened_usercopy |cmdline| 1 | kspp | self_protection | OK: CONFIG_HARDENED_USERCOPY is "y"
+slab_common.usercopy_fallback |cmdline| 0 | kspp | self_protection | OK: CONFIG_HARDENED_USERCOPY_FALLBACK is not found
+randomize_kstack_offset |cmdline| 1 | kspp | self_protection | OK: CONFIG_RANDOMIZE_KSTACK_OFFSET_DEFAULT is "y"
+pti |cmdline| on | kspp | self_protection | FAIL: is not found
+page_alloc.shuffle |cmdline| 1 | clipos | self_protection | FAIL: is not found
+iommu |cmdline| force | clipos | self_protection | FAIL: is not found
+tsx |cmdline| off |defconfig |cut_attack_surface| OK: CONFIG_X86_INTEL_TSX_MODE_OFF is "y"
+vsyscall |cmdline| none | kspp |cut_attack_surface| FAIL: is not found
+vdso32 |cmdline| 1 | my |cut_attack_surface| OK: CONFIG_COMPAT_VDSO is "is not set"
+debugfs |cmdline| off | grsec |cut_attack_surface| FAIL: is not found
+sysrq_always_enabled |cmdline| is not set | my |cut_attack_surface| OK: is not found
+norandmaps |cmdline| is not set |defconfig | harden_userspace | OK: is not found
+net.core.bpf_jit_harden |sysctl | 2 | kspp | self_protection | FAIL: "0"
+kernel.dmesg_restrict |sysctl | 1 | kspp |cut_attack_surface| FAIL: "0"
+kernel.perf_event_paranoid |sysctl | 3 | kspp |cut_attack_surface| FAIL: "2"
+kernel.kexec_load_disabled |sysctl | 1 | kspp |cut_attack_surface| FAIL: "0"
+user.max_user_namespaces |sysctl | 0 | kspp |cut_attack_surface| FAIL: "31021"
+dev.tty.ldisc_autoload |sysctl | 0 | kspp |cut_attack_surface| FAIL: "1"
+kernel.unprivileged_bpf_disabled |sysctl | 1 | kspp |cut_attack_surface| OK
+kernel.kptr_restrict |sysctl | 1 | kspp |cut_attack_surface| FAIL: "0"
+kernel.yama.ptrace_scope |sysctl | 1 | kspp |cut_attack_surface| FAIL: "0"
+
+[+] Config check is finished: 'OK' - 118 / 'FAIL' - 122
```
-__Go and fix them all!__
+## Generating a Kconfig fragment with the security hardening options
+
+With the `-g` argument, the tool generates a Kconfig fragment with the security hardening options for the selected microarchitecture.
+
+This Kconfig fragment can be merged with the existing Linux kernel config:
+```
+$ ./bin/kernel-hardening-checker -g X86_64 > /tmp/fragment
+$ cd ~/linux-src/
+$ ./scripts/kconfig/merge_config.sh .config /tmp/fragment
+Using .config as base
+Merging /tmp/fragment
+Value of CONFIG_BUG_ON_DATA_CORRUPTION is redefined by fragment /tmp/fragment:
+Previous value: # CONFIG_BUG_ON_DATA_CORRUPTION is not set
+New value: CONFIG_BUG_ON_DATA_CORRUPTION=y
+ ...
+```
+
+## Questions and answers
+
+__Q:__ How all these kernel parameters influence the Linux kernel security?
+
+__A:__ To answer this question, you can use the `kernel-hardening-checker` [sources of recommendations][24]
+and the [Linux Kernel Defence Map][4] with its references.
+
+
+
+__Q:__ How disabling `CONFIG_USER_NS` cuts the attack surface? It's needed for containers!
+
+__A:__ Yes, the `CONFIG_USER_NS` option provides some isolation between the userspace programs,
+but the tool recommends disabling it to cut the attack surface __of the kernel__.
+
+The rationale:
+
+ - An LWN article about the corresponding LKML discussion: https://lwn.net/Articles/673597/
+
+ - A twitter thread about `CONFIG_USER_NS` and security: https://twitter.com/robertswiecki/status/1095447678949953541
+
+ - A good overview of the trade-off between having user namespaces enabled, disabled and available only for root: https://github.com/NixOS/nixpkgs/pull/84522#issuecomment-614640601
+
+
+
+__Q:__ KSPP and CLIP OS recommend `CONFIG_PANIC_ON_OOPS=y`. Why doesn't this tool do the same?
+
+__A:__ I personally don't support this recommendation because:
+ - It decreases system safety (kernel oops is still not a rare situation)
+ - It allows easier denial-of-service attacks for the whole system
+
+I think having `CONFIG_BUG` is enough here.
+If a kernel oops happens in the process context, the offending/attacking process is killed.
+In other cases, the kernel panics, which is similar to `CONFIG_PANIC_ON_OOPS=y`.
+
+
+
+__Q:__ Why enabling `CONFIG_STATIC_USERMODEHELPER` breaks various things in my GNU/Linux system?
+Do I really need that feature?
+
+__A:__ Linux kernel usermode helpers can be used for privilege escalation in kernel exploits
+([example 1][9], [example 2][10]). `CONFIG_STATIC_USERMODEHELPER` prevents that method. But it
+requires the corresponding support in the userspace: see the [example implementation][11] by
+Tycho Andersen [@tych0][12].
+
+
+
+__Q:__ What about performance impact of these security hardening options?
+
+__A:__ Ike Devolder [@BlackIkeEagle][7] made some performance tests and described the results in [this article][8].
+A more detailed evaluation is in the TODO list (the issue [#66][21]).
+
+
+
+__Q:__ Can I easily check which kernel versions support some Kconfig option?
+
+__A:__ Yes. See the [LKDDb][18] project (Linux Kernel Driver Database) by Giacomo Catenazzi [@cateee][19].
+You can use it for the `mainline` or `stable` tree from [kernel.org][20] or for your custom kernel sources.
+
+
+
+__Q:__ Does my kernel have all those mitigations of Transient Execution Vulnerabilities in my hardware?
+
+__A:__ Checking the kernel config is not enough to answer this question.
+I highly recommend using [spectre-meltdown-checker][13] tool maintained by Stéphane Lesimple [@speed47][14].
+
+
+__Q:__ Why the `CONFIG_GCC_PLUGINS` option is automatically disabled during the kernel compilation?
-N.B. If `CONFIG_GCC_PLUGIN*` options are automatically disabled during your kernel compilation,
-then 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.
+__A:__ It 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.
[1]: http://kernsec.org/wiki/index.php/Kernel_Self_Protection_Project/Recommended_Settings
-[2]: https://grsecurity.net/
+[2]: https://docs.clip-os.org/clipos/kernel.html#configuration
+[3]: https://grsecurity.net/
+[4]: https://github.com/a13xp0p0v/linux-kernel-defence-map
+[5]: https://lwn.net/Articles/791863/
+[6]: https://github.com/a13xp0p0v/kernel-hardening-checker/issues/38
+[7]: https://github.com/BlackIkeEagle
+[8]: https://blog.herecura.eu/blog/2020-05-30-kconfig-hardening-tests/
+[9]: https://googleprojectzero.blogspot.com/2018/09/a-cache-invalidation-bug-in-linux.html
+[10]: https://a13xp0p0v.github.io/2020/02/15/CVE-2019-18683.html
+[11]: https://github.com/tych0/huldufolk
+[12]: https://github.com/tych0
+[13]: https://github.com/speed47/spectre-meltdown-checker
+[14]: https://github.com/speed47
+[15]: https://github.com/a13xp0p0v/kernel-hardening-checker/issues/53
+[16]: https://github.com/a13xp0p0v/kernel-hardening-checker/pull/54
+[17]: https://github.com/a13xp0p0v/kernel-hardening-checker/pull/62
+[18]: https://cateee.net/lkddb/web-lkddb/
+[19]: https://github.com/cateee/lkddb
+[20]: https://kernel.org/
+[21]: https://github.com/a13xp0p0v/kernel-hardening-checker/issues/66
+[22]: https://github.com/a13xp0p0v/kernel-hardening-checker/issues/56
+[23]: https://github.com/a13xp0p0v/kernel-hardening-checker/issues?q=label%3Akernel_maintainer_feedback
+[24]: https://github.com/a13xp0p0v/kernel-hardening-checker#motivation