X-Git-Url: https://jxself.org/git/?a=blobdiff_plain;f=README.md;h=b918ebba46c879d12f3afa9bfd2e63526ca6d5f5;hb=3630552c4a7cb10c3fb449b1f38d629744a3f91a;hp=8f2271cdbb22271382ed8c8fed0319a9df9a3b5f;hpb=75cfda0e57b77c4dbdcb0f03ba34ab238878a557;p=kconfig-hardened-check.git diff --git a/README.md b/README.md index 8f2271c..b918ebb 100644 --- a/README.md +++ b/README.md @@ -9,129 +9,218 @@ 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 hardening preferences, which are based on the -Please don't cry if my Python code looks like C. I'm just a kernel developer. + - [KSPP recommended settings][1], + - [CLIP OS kernel configuration][2], + - last public [grsecurity][3] patch (options which they disable). + +I also created [__Linux Kernel Defence Map__][4] that is a graphical representation of the +relationships between these hardening features and the corresponding vulnerability classes +or exploitation techniques. + +## Supported microarchitectures + + - X86_64 + - X86_32 + - ARM64 + - ARM ## Script output examples ### Usage ``` -#./kconfig-hardened-check.py -Usage: ./kconfig-hardened-check.py [-p | -c ] - -p, --print - print hardening preferences - -c , --config= - check the config_file against these preferences +usage: kconfig-hardened-check.py [-h] [-p {X86_64,X86_32,ARM64,ARM}] + [-c CONFIG] [--debug] [--json] + +Checks the hardening options in the Linux kernel config + +optional arguments: + -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 + -c CONFIG, --config CONFIG + check the config_file against these preferences + --debug enable internal debug mode + --json print results in JSON format + ``` -### Script output for `Ubuntu 18.04 (Bionic Beaver)` kernel config +### Script output for `Ubuntu 18.04 (Bionic Beaver with HWE)` kernel config ``` -./kconfig-hardened-check.py -c config_files/ubuntu-bionic-generic.config -[+] Checking "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 +$ ./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 | OK +CONFIG_SLUB_DEBUG | y |defconfig | self_protection | OK +CONFIG_STRICT_MODULE_RWX | 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_IOMMU_SUPPORT | y |defconfig | self_protection | OK +CONFIG_SYN_COOKIES | y |defconfig | self_protection | OK +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_VMAP_STACK | y |defconfig | self_protection | OK +CONFIG_RANDOMIZE_BASE | 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_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_GCC_PLUGINS | y | kspp | self_protection | FAIL: not found +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_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_DEFAULT_MMAP_MIN_ADDR | 65536 | kspp | self_protection | OK +CONFIG_REFCOUNT_FULL | y | kspp | self_protection | FAIL: "is not set" +CONFIG_INIT_STACK_ALL | y | clipos | self_protection | FAIL: not found +CONFIG_INIT_ON_ALLOC_DEFAULT_ON | y | clipos | self_protection | OK +CONFIG_INIT_ON_FREE_DEFAULT_ON | y | clipos | self_protection | OK: CONFIG_PAGE_POISONING "y" +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_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_GCC_PLUGIN_STACKLEAK | y | clipos | 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_RANDOM_TRUST_CPU | is not set | clipos | self_protection | FAIL: "y" +CONFIG_INTEL_IOMMU_SVM | y | clipos | self_protection | OK +CONFIG_INTEL_IOMMU_DEFAULT_ON | y | clipos | self_protection | FAIL: "is not set" +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_WRITABLE_HOOKS | is not set |defconfig | security_policy | OK: not found +CONFIG_SECURITY_YAMA | y | kspp | security_policy | OK +CONFIG_SECURITY_LOADPIN | y | my | security_policy | FAIL: "is not set" +CONFIG_SECURITY_LOCKDOWN_LSM | y | my | security_policy | FAIL: not found +CONFIG_SECURITY_LOCKDOWN_LSM_EARLY | y | my | security_policy | FAIL: not found +CONFIG_LOCK_DOWN_KERNEL_FORCE_CONFIDENTIALITY| y | my | security_policy | FAIL: not found +CONFIG_SECURITY_SAFESETID | y | my | 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_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_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_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_LDISC_AUTOLOAD | is not set | clipos | cut_attack_surface | FAIL: "y" +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_ARCH_MMAP_RND_BITS | 32 | clipos |userspace_hardening | FAIL: "28" + +[+] config check is finished: 'OK' - 50 / 'FAIL' - 73 ``` -__Go and fix them all!__ +## kconfig-hardened-check versioning + +I usually update the kernel 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]__ + +The current version of `kconfig-hardened-check` is __0.5.3__, it's marked with the git tag. + + +## 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 script 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 + +
+ +__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. + +
+ +__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. [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