## Usage
```
-usage: kconfig-hardened-check [-h] [-p {X86_64,X86_32,ARM64,ARM}] [-c CONFIG]
- [--debug] [--json] [--version]
+usage: kconfig-hardened-check [-h] [--version] [-p {X86_64,X86_32,ARM64,ARM}]
+ [-c CONFIG]
+ [-m {verbose,json,show_ok,show_fail}]
Checks the hardening options in the Linux kernel config
optional arguments:
-h, --help show this help message and exit
+ --version show program's version number and exit
-p {X86_64,X86_32,ARM64,ARM}, --print {X86_64,X86_32,ARM64,ARM}
print hardening preferences for selected architecture
-c CONFIG, --config CONFIG
- check the config_file against these preferences
- --debug enable verbose debug mode
- --json print results in JSON format
- --version show program's version number and exit
+ 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
```
-## Output for `Ubuntu 18.04 (Bionic Beaver with HWE)` kernel config
+## Output for `Ubuntu 20.04 LTS (Focal Fossa)` kernel config
```
-$ ./bin/kconfig-hardened-check -c kconfig_hardened_check/config_files/distros/ubuntu-bionic-generic.config
-[+] Trying to detect architecture in "kconfig_hardened_check/config_files/distros/ubuntu-bionic-generic.config"...
+$ ./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
-[+] Trying to detect kernel version in "kconfig_hardened_check/config_files/distros/ubuntu-bionic-generic.config"...
-[+] Found version line: "# Linux/x86 5.3.0-28-generic Kernel Configuration"
-[+] Detected kernel version: 5.3
-[+] Checking "kconfig_hardened_check/config_files/distros/ubuntu-bionic-generic.config" against X86_64 hardening preferences...
+[+] Detected kernel version: 5.4
=========================================================================================================================
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 | OK
CONFIG_SLUB_DEBUG | y |defconfig | self_protection | OK
-CONFIG_STRICT_MODULE_RWX | 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_MICROCODE | y |defconfig | self_protection | OK
CONFIG_RETPOLINE | y |defconfig | self_protection | OK
CONFIG_X86_SMAP | y |defconfig | self_protection | OK
-CONFIG_X86_UMIP | y |defconfig | self_protection | OK: CONFIG_X86_INTEL_UMIP "y"
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_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_GCC_PLUGIN_RANDSTRUCT | 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_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_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 | y | kspp | self_protection | FAIL: not found
-CONFIG_INIT_ON_ALLOC_DEFAULT_ON | y | kspp | self_protection | OK
-CONFIG_INIT_ON_FREE_DEFAULT_ON | y | kspp | self_protection | OK: CONFIG_PAGE_POISONING "y"
+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_STACKLEAK_METRICS | is not set | clipos | self_protection | FAIL: CONFIG_GCC_PLUGIN_STACKLEAK is needed
-CONFIG_STACKLEAK_RUNTIME_DISABLE | is not set | clipos | self_protection | FAIL: CONFIG_GCC_PLUGIN_STACKLEAK is needed
CONFIG_DEFAULT_MMAP_MIN_ADDR | 65536 | kspp | self_protection | OK
CONFIG_SECURITY_DMESG_RESTRICT | y | clipos | self_protection | FAIL: "is not set"
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_GCC_PLUGIN_RANDSTRUCT_PERFORMANCE | is not set | clipos | self_protection | FAIL: CONFIG_GCC_PLUGIN_RANDSTRUCT is needed
-CONFIG_RANDOM_TRUST_BOOTLOADER | is not set | clipos | self_protection | OK: not found
+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_SVM | y | clipos | self_protection | OK
CONFIG_INTEL_IOMMU_DEFAULT_ON | y | clipos | self_protection | FAIL: "is not set"
+CONFIG_UBSAN_BOUNDS | y | my | self_protection | FAIL: CONFIG_UBSAN_TRAP not "y"
CONFIG_SLUB_DEBUG_ON | y | my | self_protection | FAIL: "is not set"
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 | FAIL: not found
-CONFIG_SECURITY_LOCKDOWN_LSM_EARLY | y | clipos | security_policy | FAIL: not found
-CONFIG_LOCK_DOWN_KERNEL_FORCE_CONFIDENTIALITY| y | clipos | security_policy | FAIL: not found
-CONFIG_SECURITY_LOADPIN | y | my | security_policy | FAIL: "is not set"
-CONFIG_SECURITY_LOADPIN_ENFORCE | y | my | security_policy | FAIL: CONFIG_SECURITY_LOADPIN is needed
+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_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_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_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_X86_PTDUMP | is not set |grsecurity| cut_attack_surface | OK
+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_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_ACPI_TABLE_UPGRADE | is not set | lockdown | cut_attack_surface | FAIL: "y"
-CONFIG_X86_IOPL_IOPERM | is not set | lockdown | cut_attack_surface | OK: not found
-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_X86_INTEL_TSX_MODE_OFF | y | clipos | cut_attack_surface | OK
+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_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_AIO | is not set |grapheneos| 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_BPF_JIT | 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' - 56 / 'FAIL' - 79
+[+] Config check is finished: 'OK' - 58 / 'FAIL' - 82
```
## kconfig-hardened-check versioning
- 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?
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 kernel 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://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