-# Kconfig hardened check
+# kconfig-hardened-check
+
+
+[](https://codecov.io/gh/a13xp0p0v/kconfig-hardened-check)
## Motivation
-There are plenty of Linux kernel hardening config options. A lot of them are
+There are plenty of security hardening options in 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 for `x86_64`, which are based on the
-[KSPP recommended settings][1] and last public [grsecurity][2] patch (options
-which they disable).
+against my security hardening preferences, which are based on the
+
+ - [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 Linux kernel maintainers (Daniel Vetter in [issue #38][6]).
+
+I also created [__Linux Kernel Defence Map__][4] that is a graphical representation of the
+relationships between security hardening features and the corresponding vulnerability classes
+or exploitation techniques.
+
+## Supported microarchitectures
+
+ - X86_64
+ - X86_32
+ - ARM64
+ - ARM
-Please don't cry if my Python code looks like C. I'm just a kernel developer.
+## Installation
-## Script output examples
+You can install the package:
-### Usage
```
-#./kconfig-hardened-check.py
-usage: kconfig-hardened-check.py [-h] [-p] [-c CONFIG] [--debug]
+pip install git+https://github.com/a13xp0p0v/kconfig-hardened-check
+```
+
+or simply run `./bin/kconfig-hardened-check` from the cloned repository.
-Checks the hardening options in the Linux kernel config
+## Usage
+```
+usage: kconfig-hardened-check [-h] [--version] [-p {X86_64,X86_32,ARM64,ARM}]
+ [-c CONFIG]
+ [-m {verbose,json,show_ok,show_fail}]
+
+A tool for checking the security hardening options of the Linux kernel
optional arguments:
-h, --help show this help message and exit
- -p, --print print hardening preferences
+ --version show program's version number and exit
+ -p {X86_64,X86_32,ARM64,ARM}, --print {X86_64,X86_32,ARM64,ARM}
+ print security hardening preferences for the selected architecture
-c CONFIG, --config CONFIG
- check the config_file against these preferences
- --debug enable internal debug mode
+ check the kernel config file against these preferences
+ -m {verbose,json,show_ok,show_fail}, --mode {verbose,json,show_ok,show_fail}
+ choose the report mode
```
-### Script output for `Ubuntu 18.04 (Bionic Beaver)` kernel config
+## Output for `Ubuntu 20.04 LTS (Focal Fossa)` kernel config
```
-#./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_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_RANDOMIZE_BASE | y | ubuntu18 | self_protection || OK
- CONFIG_RANDOMIZE_MEMORY | y | ubuntu18 | self_protection || OK
- CONFIG_CC_STACKPROTECTOR | y | ubuntu18 | self_protection || OK
- CONFIG_CC_STACKPROTECTOR_STRONG | y | ubuntu18 | self_protection || OK
- 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_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_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_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_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_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_PROFILING | 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_ARCH_MMAP_RND_BITS | 32 | my |userspace_protection|| FAIL: "28"
- CONFIG_LKDTM | m | my | feature_test || FAIL: "is not set"
-
-[-] config check is NOT PASSED: 52 errors
+$ ./bin/kconfig-hardened-check -c kconfig_hardened_check/config_files/distros/ubuntu-focal.config
+[+] Config file to check: kconfig_hardened_check/config_files/distros/ubuntu-focal.config
+[+] Detected architecture: X86_64
+[+] Detected kernel version: 5.4
+=========================================================================================================================
+ option name | desired val | decision | reason | check result
+=========================================================================================================================
+CONFIG_BUG | y |defconfig | self_protection | OK
+CONFIG_SLUB_DEBUG | y |defconfig | self_protection | OK
+CONFIG_GCC_PLUGINS | y |defconfig | self_protection | FAIL: not found
+CONFIG_STACKPROTECTOR_STRONG | y |defconfig | self_protection | OK
+CONFIG_STRICT_KERNEL_RWX | y |defconfig | self_protection | OK
+CONFIG_STRICT_MODULE_RWX | y |defconfig | self_protection | OK
+CONFIG_REFCOUNT_FULL | y |defconfig | self_protection | FAIL: "is not set"
+CONFIG_IOMMU_SUPPORT | y |defconfig | self_protection | OK
+CONFIG_RANDOMIZE_BASE | y |defconfig | self_protection | OK
+CONFIG_THREAD_INFO_IN_TASK | y |defconfig | self_protection | OK
+CONFIG_VMAP_STACK | y |defconfig | self_protection | OK
+CONFIG_MICROCODE | y |defconfig | self_protection | OK
+CONFIG_RETPOLINE | y |defconfig | self_protection | OK
+CONFIG_X86_SMAP | y |defconfig | self_protection | OK
+CONFIG_SYN_COOKIES | y |defconfig | self_protection | OK
+CONFIG_X86_UMIP | y |defconfig | self_protection | OK: CONFIG_X86_INTEL_UMIP "y"
+CONFIG_PAGE_TABLE_ISOLATION | y |defconfig | self_protection | OK
+CONFIG_RANDOMIZE_MEMORY | y |defconfig | self_protection | OK
+CONFIG_INTEL_IOMMU | y |defconfig | self_protection | OK
+CONFIG_AMD_IOMMU | y |defconfig | self_protection | OK
+CONFIG_SECURITY_DMESG_RESTRICT | y | kspp | self_protection | FAIL: "is not set"
+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_SLAB_FREELIST_HARDENED | y | kspp | self_protection | OK
+CONFIG_SLAB_FREELIST_RANDOM | y | kspp | self_protection | OK
+CONFIG_SHUFFLE_PAGE_ALLOCATOR | y | kspp | self_protection | OK
+CONFIG_FORTIFY_SOURCE | y | kspp | self_protection | OK
+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_INIT_ON_ALLOC_DEFAULT_ON | y | kspp | self_protection | OK
+CONFIG_GCC_PLUGIN_LATENT_ENTROPY | y | kspp | self_protection | FAIL: not found
+CONFIG_GCC_PLUGIN_RANDSTRUCT | y | kspp | self_protection | FAIL: not found
+CONFIG_HARDENED_USERCOPY | y | kspp | self_protection | OK
+CONFIG_HARDENED_USERCOPY_FALLBACK | is not set | kspp | self_protection | FAIL: "y"
+CONFIG_HARDENED_USERCOPY_PAGESPAN | is not set | kspp | self_protection | OK
+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_INIT_STACK_ALL_ZERO | y | kspp | self_protection | FAIL: not found
+CONFIG_INIT_ON_FREE_DEFAULT_ON | y | kspp | self_protection | OK: CONFIG_PAGE_POISONING_ZERO "y"
+CONFIG_GCC_PLUGIN_STACKLEAK | y | kspp | self_protection | FAIL: not found
+CONFIG_RANDOMIZE_KSTACK_OFFSET_DEFAULT | y | kspp | self_protection | FAIL: not found
+CONFIG_DEFAULT_MMAP_MIN_ADDR | 65536 | kspp | self_protection | OK
+CONFIG_UBSAN_BOUNDS | y |maintainer| self_protection | FAIL: not found
+CONFIG_UBSAN_SANITIZE_ALL | y |maintainer| self_protection | FAIL: CONFIG_UBSAN_BOUNDS not "y"
+CONFIG_UBSAN_TRAP | y |maintainer| self_protection | FAIL: CONFIG_UBSAN_BOUNDS not "y"
+CONFIG_DEBUG_VIRTUAL | y | clipos | self_protection | FAIL: "is not set"
+CONFIG_STATIC_USERMODEHELPER | y | clipos | self_protection | FAIL: "is not set"
+CONFIG_EFI_DISABLE_PCI_DMA | y | clipos | self_protection | FAIL: not found
+CONFIG_SLAB_MERGE_DEFAULT | is not set | clipos | self_protection | FAIL: "y"
+CONFIG_RANDOM_TRUST_BOOTLOADER | is not set | clipos | self_protection | FAIL: "y"
+CONFIG_RANDOM_TRUST_CPU | is not set | clipos | self_protection | FAIL: "y"
+CONFIG_GCC_PLUGIN_RANDSTRUCT_PERFORMANCE | is not set | clipos | self_protection | FAIL: CONFIG_GCC_PLUGIN_RANDSTRUCT not "y"
+CONFIG_STACKLEAK_METRICS | is not set | clipos | self_protection | FAIL: CONFIG_GCC_PLUGIN_STACKLEAK not "y"
+CONFIG_STACKLEAK_RUNTIME_DISABLE | is not set | clipos | self_protection | FAIL: CONFIG_GCC_PLUGIN_STACKLEAK not "y"
+CONFIG_INTEL_IOMMU_DEFAULT_ON | y | clipos | self_protection | FAIL: "is not set"
+CONFIG_INTEL_IOMMU_SVM | y | clipos | self_protection | OK
+CONFIG_RESET_ATTACK_MITIGATION | y | my | self_protection | OK
+CONFIG_AMD_IOMMU_V2 | y | my | self_protection | FAIL: "m"
+CONFIG_SECURITY | y |defconfig | security_policy | OK
+CONFIG_SECURITY_YAMA | y | kspp | security_policy | OK
+CONFIG_SECURITY_WRITABLE_HOOKS | is not set | my | security_policy | OK: not found
+CONFIG_SECURITY_LOCKDOWN_LSM | y | clipos | security_policy | OK
+CONFIG_SECURITY_LOCKDOWN_LSM_EARLY | y | clipos | security_policy | OK
+CONFIG_LOCK_DOWN_KERNEL_FORCE_CONFIDENTIALITY| y | clipos | security_policy | FAIL: "is not set"
+CONFIG_SECURITY_SAFESETID | y | my | security_policy | OK
+CONFIG_SECURITY_LOADPIN | y | my | security_policy | FAIL: "is not set"
+CONFIG_SECURITY_LOADPIN_ENFORCE | y | my | security_policy | FAIL: CONFIG_SECURITY_LOADPIN not "y"
+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_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_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_OABI_COMPAT | is not set | kspp | cut_attack_surface | OK: not found
+CONFIG_MODULES | is not set | kspp | cut_attack_surface | FAIL: "y"
+CONFIG_DEVMEM | is not set | kspp | cut_attack_surface | FAIL: "y"
+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_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_X86_PTDUMP | is not set |grsecurity| cut_attack_surface | OK
+CONFIG_DRM_LEGACY | is not set |maintainer| cut_attack_surface | OK
+CONFIG_FB | is not set |maintainer| cut_attack_surface | FAIL: "y"
+CONFIG_VT | is not set |maintainer| cut_attack_surface | FAIL: "y"
+CONFIG_BLK_DEV_FD | is not set |maintainer| cut_attack_surface | FAIL: "m"
+CONFIG_AIO | is not set |grapheneos| cut_attack_surface | FAIL: "y"
+CONFIG_STAGING | is not set | clipos | cut_attack_surface | FAIL: "y"
+CONFIG_KSM | is not set | clipos | cut_attack_surface | FAIL: "y"
+CONFIG_KALLSYMS | is not set | clipos | cut_attack_surface | FAIL: "y"
+CONFIG_X86_VSYSCALL_EMULATION | is not set | clipos | cut_attack_surface | FAIL: "y"
+CONFIG_MAGIC_SYSRQ | is not set | clipos | cut_attack_surface | FAIL: "y"
+CONFIG_KEXEC_FILE | is not set | clipos | cut_attack_surface | FAIL: "y"
+CONFIG_USER_NS | is not set | clipos | cut_attack_surface | FAIL: "y"
+CONFIG_X86_MSR | is not set | clipos | cut_attack_surface | FAIL: "m"
+CONFIG_X86_CPUID | is not set | clipos | cut_attack_surface | FAIL: "m"
+CONFIG_IO_URING | is not set | clipos | cut_attack_surface | FAIL: "y"
+CONFIG_X86_IOPL_IOPERM | is not set | clipos | cut_attack_surface | OK: not found
+CONFIG_ACPI_TABLE_UPGRADE | is not set | clipos | cut_attack_surface | FAIL: "y"
+CONFIG_EFI_CUSTOM_SSDT_OVERLAYS | is not set | clipos | cut_attack_surface | OK: not found
+CONFIG_LDISC_AUTOLOAD | is not set | clipos | cut_attack_surface | FAIL: "y"
+CONFIG_X86_INTEL_TSX_MODE_OFF | y | clipos | cut_attack_surface | OK
+CONFIG_EFI_TEST | is not set | lockdown | cut_attack_surface | FAIL: "m"
+CONFIG_BPF_SYSCALL | is not set | lockdown | cut_attack_surface | FAIL: "y"
+CONFIG_MMIOTRACE_TEST | is not set | lockdown | cut_attack_surface | OK
+CONFIG_TRIM_UNUSED_KSYMS | y | my | cut_attack_surface | FAIL: not found
+CONFIG_MMIOTRACE | is not set | my | cut_attack_surface | FAIL: "y"
+CONFIG_LIVEPATCH | 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_VIDEO_VIVID | is not set | my | cut_attack_surface | FAIL: "m"
+CONFIG_INPUT_EVBUG | is not set | my | cut_attack_surface | FAIL: "m"
+CONFIG_INTEGRITY | y |defconfig |userspace_hardening | OK
+CONFIG_ARCH_MMAP_RND_BITS | 32 | clipos |userspace_hardening | FAIL: "28"
+
+[+] Config check is finished: 'OK' - 59 / 'FAIL' - 85
```
-__Go and fix them all!__
+## kconfig-hardened-check versioning
+
+I usually update the kernel security hardening recommendations after each Linux kernel release.
+
+So the version of `kconfig-hardened-check` is associated with the corresponding version of the kernel.
+
+The version format is: __[major_number].[kernel_version].[kernel_patchlevel]__
+
+
+## Questions and answers
+
+__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:
+
+ - A nice 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
+
+<br />
+
+__Q:__ Why `CONFIG_GCC_PLUGINS` is automatically disabled during the kernel compilation?
+
+__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.
+
+<br />
+
+__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 provides easy denial-of-service
+attacks for the whole system (kernel oops is not a rare situation). I think having `CONFIG_BUG` is enough here --
+if we have a kernel oops in the process context, the offending/attacking process is killed.
+
+<br />
+
+__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].
+
+<br />
+
+__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].
+
+<br />
+
+__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].
+
[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/kconfig-hardened-check/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
projects / kconfig-hardened-check.git / blobdiff