From 54216d0d8366e74bf4a6e4a935b801a2cfe1e12a Mon Sep 17 00:00:00 2001 From: Alexander Popov Date: Mon, 14 Aug 2023 15:22:34 +0300 Subject: [PATCH] Update the README (add the --sysctl mode) --- README.md | 111 +++++++++++++++++++++++++++++++++--------------------- 1 file changed, 68 insertions(+), 43 deletions(-) diff --git a/README.md b/README.md index 714bb4a..f10ac37 100644 --- a/README.md +++ b/README.md @@ -14,8 +14,13 @@ make our systems more secure. But nobody likes checking configs manually. So let the computers do their job! -__kconfig-hardened-check__ is a tool for checking the security hardening options of the Linux kernel. -The recommendations are based on +__kconfig-hardened-check__ 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] @@ -23,14 +28,12 @@ The recommendations are based on - [SECURITY_LOCKDOWN_LSM][5] patchset - [Direct feedback from the Linux kernel maintainers][23] -This tool supports checking __Kconfig__ options and __kernel cmdline__ parameters. - 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 +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. @@ -64,7 +67,8 @@ Some Linux distributions also provide `kconfig-hardened-check` as a package. ## Usage ``` usage: kconfig-hardened-check [-h] [--version] [-m {verbose,json,show_ok,show_fail}] - [-c CONFIG] [-l CMDLINE] [-p {X86_64,X86_32,ARM64,ARM}] + [-c CONFIG] [-l CMDLINE] [-s SYSCTL] + [-p {X86_64,X86_32,ARM64,ARM}] [-g {X86_64,X86_32,ARM64,ARM}] A tool for checking the security hardening options of the Linux kernel @@ -80,6 +84,9 @@ options: -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 @@ -97,32 +104,33 @@ options: ``` ------------------------------------------------------------------------------------------- <<< OR >>> -CONFIG_STRICT_DEVMEM | y |defconfig | cut_attack_surface -CONFIG_DEVMEM | is not set | kspp | cut_attack_surface +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 `kconfig-hardened-check` with other tools) -## Example output for `Fedora 36` kernel configuration +## Example output for `Fedora 38` kernel configuration ``` -$ ./bin/kconfig-hardened-check -c /boot/config-6.0.18-200.fc36.x86_64 -l /proc/cmdline -[+] Kconfig file to check: /boot/config-6.0.18-200.fc36.x86_64 +$ ./bin/kconfig-hardened-check -c kconfig_hardened_check/config_files/distros/fedora_38.config -l /proc/cmdline -s kconfig_hardened_check/config_files/distros/example_sysctls.txt +[+] Kconfig file to check: kconfig_hardened_check/config_files/distros/fedora_38.config [+] Kernel cmdline file to check: /proc/cmdline -[+] Detected architecture: X86_64 -[+] Detected kernel version: 6.0 -[+] Detected compiler: GCC 120201 +[+] Sysctl output file to check: kconfig_hardened_check/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 | 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 | FAIL: "is not set" +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 @@ -140,6 +148,7 @@ CONFIG_X86_SMAP |kconfig| y |defconfig | self_p 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 @@ -158,12 +167,12 @@ CONFIG_KFENCE |kconfig| y | kspp | self_p 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 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: "is not set" +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 @@ -176,9 +185,9 @@ CONFIG_UBSAN_BOUNDS |kconfig| y | kspp | self_p 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: "is not set" -CONFIG_STACKLEAK_METRICS |kconfig| is not set | kspp | self_protection | FAIL: CONFIG_GCC_PLUGIN_STACKLEAK is not "y" -CONFIG_STACKLEAK_RUNTIME_DISABLE |kconfig| is not set | kspp | self_protection | FAIL: CONFIG_GCC_PLUGIN_STACKLEAK 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" @@ -201,6 +210,7 @@ CONFIG_SECURITY_LOCKDOWN_LSM |kconfig| y | kspp | securi 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 @@ -210,7 +220,6 @@ CONFIG_SECURITY_DMESG_RESTRICT |kconfig| y | kspp |cut_att 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_COMPAT_VDSO |kconfig| is not set | kspp |cut_attack_surface| OK 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" @@ -228,7 +237,7 @@ CONFIG_MODULES |kconfig| is not set | kspp |cut_att 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_LEGACY_VSYSCALL_NONE |kconfig| y | kspp |cut_attack_surface| FAIL: "is not set" +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 @@ -272,10 +281,10 @@ CONFIG_FB |kconfig| is not set |maintainer|cut_att 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_X86_VSYSCALL_EMULATION |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" @@ -284,21 +293,25 @@ CONFIG_X86_IOPL_IOPERM |kconfig| is not set | clipos |cut_att 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| OK: is not found +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_INTEGRITY |kconfig| y |defconfig | harden_userspace | OK -CONFIG_ARCH_MMAP_RND_BITS |kconfig| 32 | clipos | harden_userspace | FAIL: "28" +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 @@ -310,23 +323,24 @@ nospec_store_bypass_disable |cmdline| is not set |defconfig | self_p 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 -mitigations |cmdline| is not off |defconfig | self_protection | OK: mitigations is not found -spectre_v2 |cmdline| is not off |defconfig | self_protection | OK: spectre_v2 is not found -spectre_v2_user |cmdline| is not off |defconfig | self_protection | OK: spectre_v2_user is not found -spec_store_bypass_disable |cmdline| is not off |defconfig | self_protection | OK: spec_store_bypass_disable is not found -l1tf |cmdline| is not off |defconfig | self_protection | OK: l1tf is not found -mds |cmdline| is not off |defconfig | self_protection | OK: mds is not found -tsx_async_abort |cmdline| is not off |defconfig | self_protection | OK: tsx_async_abort is not found -srbds |cmdline| is not off |defconfig | self_protection | OK: srbds is not found -mmio_stale_data |cmdline| is not off |defconfig | self_protection | OK: mmio_stale_data is not found -retbleed |cmdline| is not off |defconfig | self_protection | OK: retbleed is not found -kpti |cmdline| is not off |defconfig | self_protection | OK: kpti is not found -kvm.nx_huge_pages |cmdline| is not off |defconfig | self_protection | OK: kvm.nx_huge_pages is not found -rodata |cmdline| 1 |defconfig | self_protection | OK: rodata 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 -slab_nomerge |cmdline| is present | kspp | self_protection | OK: CONFIG_SLAB_MERGE_DEFAULT is "is not set" 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" @@ -337,10 +351,21 @@ page_alloc.shuffle |cmdline| 1 | clipos | self_p 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 - -[+] Config check is finished: 'OK' - 122 / 'FAIL' - 101 +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 ``` ## Generating a Kconfig fragment with the security hardening options -- 2.31.1