added kernel configs + mklocalmodule, edited config of non-critical host to use it for testing
This commit is contained in:
parent
9c0691d133
commit
2d8a53db82
4 changed files with 377 additions and 23 deletions
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@ -8,6 +8,7 @@
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./../../meta/profiles/vm.nix
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];
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lyn.sops.secrets."hosts/forgejo-ci/forgejo_ci_token" = {};
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lyn.kernel = enable ["latest" "hardened"];
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# Use UEFI
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boot.loader.systemd-boot.enable = true;
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302
kernel/hardened.nix
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302
kernel/hardened.nix
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@ -0,0 +1,302 @@
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{lib, pkgs, config, ...}: let
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ifApparmor = config.l.kernel.lsm.apparmor.enable;
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in config.l.lib.mkLocalModule ./hardened.nix "custom hardened linux kernel" {
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boot.kernelPackages = let
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kernel = pkgs.linux-libre;
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llvm = pkgs.llvmPackages_latest;
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version = pkgs.kernelPatches.hardened${kernel.meta.branch}.version;
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major = lib.versions.major version;
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sha256 = pkgs.kernelPatches.hardened.${kernel.meta.branch}.sha256;
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modDirVer = lib.replaceStrings
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[ kernel.version ]
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[ version ]
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kernel.modDirVersion;
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in lib.mkDefault (pkgs.linuxPackagesFor (kernel.override {
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stdenv = llvm.stdenv;
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extraMakeFlags = [ "LLVM=${llvm.bintools-unwrapped}/bin/" ];
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kernelPatches = kernel.kernelPatches
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++ [ pkgs.kernelPatches.hardened.${kernel.meta.branch} ];
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modDirVersionArg =
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modDirVer +
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(pkgs.kernelPatches.hardened.${kernel.meta.branch}).extra;
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isHardened = true;
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argsOverride = {
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inherit version;
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src = pkgs.fetchurl {
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url =
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"mirror://kernel/linux/kernel/v${major}.x/linux-${version}.tar.xz";
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inherit sha256;
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};
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};
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structuredExtraConfig = with lib.kernel; {
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# report BUG() conditions and kill the offending process
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BUG = yes;
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# safer page access permissions to prevent code injection
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DEBUG_RODATA = yes;
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SET_MODULE_RONX = yes;
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# validation of commonly targeted structures
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DEBUG_CREDENTIALS = yes;
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DEBUG_NOTIFIERS = yes;
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DEBUG_PLIST = yes;
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DEBUG_SG = yes;
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SCHED_STACK_END_CHECK = yes;
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# randomize page allocator when page_alloc.shuffle=1
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SHUFFLE_PAGE_ALLOCATOR = yes;
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# allow enabling slub/slab free poisoning with slub_debug=P
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SLUB_DEBUG = yes;
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# wipe higher-level memory allocations on free() with page_poison=1
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PAGE_POISONING = yes;
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PAGE_POISONING_NO_SANITY = yes;
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PAGE_POISONING_ZERO = yes;
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# reboot devices immediately when the kernel panics
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PANIC_TIMEOUT = freeform "-1";
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## GCC options (i use LLVM btw) ##
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# GCC_PLUGINS = yes; # Enable gcc plugin options
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# Gather additional entropy at boot time for systems that may not
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# have appropriate entropy sources.
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# GCC_PLUGIN_LATENT_ENTROPY = yes;
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# GCC_PLUGIN_STRUCTLEAK = yes; # A port of the PaX structleak plugin
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# GCC_PLUGIN_STRUCTLEAK_BYREF_ALL = yes; # also cover structs passed by address
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# GCC_PLUGIN_STACKLEAK = yes; # A port of the PaX stackleak plugin
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# GCC_PLUGIN_RANDSTRUCT = yes; # A port of the PaX randstruct plugin
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# GCC_PLUGIN_RANDSTRUCT_PERFORMANCE = yes;
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# enable link-time optimisation
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LTO_CLANG_THIN = yes;
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# clear memory at reboot via EFI
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# https://trustedcomputinggroup.org/resource/pc-client-work-group-platform-reset-attack-mitigation-specification/
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# https://bugzilla.redhat.com/show_bug.cgi?id=1532058
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RESET_ATTACK_MITIGATION = yes;
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# kernel memory permission enforcement
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STRICT_KERNEL_RWX = yes;
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STRICT_MODULE_RWX = yes;
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VMAP_STACK = yes;
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# kernel image and memory ASLR
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RANDOMIZE_BASE = yes;
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RANDOMIZE_MEMORY = yes;
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# randomize allocator freelists, harden metadata
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SLAB_FREELIST_RANDOM = yes;
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SLAB_FREELIST_HARDENED = yes;
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SHUFFLE_PAGE_ALLOCATOR = yes;
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RANDOM_KMALLOC_CACHES = yes;
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# sanity check userspace page table mappings
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PAGE_TABLE_CHECK = yes;
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PAGE_TABLE_CHECK_ENFORCED = yes;
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# randomize kernel stack offset on syscall entry
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RANDOMIZE_KSTACK_OFFSET_DEFAULT = yes;
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# stack frame overflow protection
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STACKPROTECTOR = yes;
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STACKPROTECTOR_STRONG = yes;
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# buffer length bounds checking
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HARDENED_USERCOPY = yes;
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FORTIFY_SOURCE = yes;
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# array index bounds checking
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UBSAN = yes;
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UBSAN_TRAP = yes;
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UBSAN_BOUNDS = yes;
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UBSAN_ALIGNMENT = yes;
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## unaligned memory access is bad and evil!!
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## sanitizing this will cause lots of reports and warnings though
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## it works on x86 though i think
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UBSAN_SHIFT = unset;
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UBSAN_DIV_ZERO = unset;
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UBSAN_UNREACHABLE = unset;
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UBSAN_SIGNED_WRAP = unset;
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UBSAN_BOOL = unset;
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UBSAN_ENUM = unset;
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# sampling-based heap out-of-bounds and user-after-free detection
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KFENCE = yes;
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# linked list integrity checking
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LIST_HARDENED = yes;
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# zero-initialise heap variables on allocation
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INIT_ON_ALLOC_DEFAULT =yes;
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# zero-initialise stack variables on function entry
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INIT_STACK_ALL_ZERO = yes;
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# disable DMA between EFI hand-off and the kernel's IOMMU setup
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EFI_DISABLE_PCI_DMA = yes;
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# force IOMMU TLB invalidation so devices will never be able to
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# access stale data content
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IOMMU_SUPPORT = yes;
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IOMMU_DEFAULT_DMA_STRICT = yes;
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# do not allow direct physical memory access to non-device memory
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STRICT_DEVMEM = option no; # depends on DEVMEM
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IO_STRICT_DEVMEM = option no; # depends on DEVMEM
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# provide userspace with seccomp BPF API
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# for syscall attack surface reduction
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SECCOMP = yes;
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SECCOMP_FILTER = yes;
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# provides some protections against SYN flooding
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SYN_COOKIES = yes;
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# enable kernel control flow integrity (currently Clang only)
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CFI_CLANG = yes;
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# CFI_PERMISSIVE
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# attack surface reduction; do not autoload TTY line disciplines
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LDISC_AUTOLOAD = no;
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# dangerous; enabling this disables userpace brk ASLR
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COMPAT_BRK = no;
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# dangerous; exposes kernel text image layout
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PROC_KCORE = no;
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# dangerous; enabling this disables userspace VDSO ASLR
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COMPAT_VDSO = no;
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# attack surface reduction: use modern PTY interface (devpts) only
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LEGACY_PTYS = no;
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# dangerous; allows writing directly to physical memory
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ACPI_CUSTOM_METHOD = no;
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# attack surface reduction; has been used for heap based attacks
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INET_DIAG = no;
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# Security modules
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SECURITY_SELINUX = yes;
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SECURITY_APPARMOR = yes;
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SECURITY_SAFESETID = yes;
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DEFAULT_SECURITY_APPARMOR = lib.mkIf ifApparmor yes;
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DEFAULT_SECURITY = lib.mkIf ifApparmor (freeform "apparmor");
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SECURITY_APPARMOR_BOOTPARAM_VALUE = lib.mkIf ifApparmor (freeform "1";)
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# mark LSM hooks read-only after init
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SECURITY_WRITABLE_HOOKS = no;
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# enable BPF; may expose kernel to spray attacks though
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BPF_JIT_ALWAYS_ON = yes;
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# Replace menu governour with TEO
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CPU_IDLE_GOV_MENU = no;
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CPU_IDLE_GOV_TEO = yes;
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} // lib.optionalAttrs pkgs.stdenv.hostPlatform.isx86_64 {
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X86_EXTENDED_PLATFORM = no;
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# don't sanitize unaligned memory access resulting in
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# undefined behavior because x86 supports unalligned access
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UBSAN_ALIGNMENT = no;
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# enable chip-specific IOMMU support
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INTEL_IOMMU = yes;
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INTEL_IOMMU_DEFAULT_ON = yes;
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INTEL_IOMMU_SVM = yes;
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AMD_IOMMU = yes;
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# enforce CET Indirect Branch Tracking in the kernel
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X86_KERNEL_IBT = yes;
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# enable CET shadow stack for userspace
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X86_USER_SHADOW_STACK = yes;
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# disable legacy x86 interfaces
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STRICT_SIGALTSTACK_SIZE = yes;
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LEGACY_VSYSCALL_XONLY = no;
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# modern libc no longer needs a fixed-position mapping in userspace,
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# remove it as a possible target
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LEGACY_VSYSCALL_NONE = yes;
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# disable IO delay
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IO_DELAY_NONE = yes;
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};
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}))
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boot.kernelParams = [
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# set apparmor as the default security module
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(lib.mkIf ifApparmor "security=apparmor")
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# zero-fill page and slab allocations
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"init_on_free=1"
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# disable IO delay
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"io_delay=none"
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# enable page allocator free list randomization
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"page_alloc.shuffle=1"
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# overwrite free()'d pages
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"page_poison=1"
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# disable slab merging
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"slab_nomerge"
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# disable vsyscall mechanism
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"vsyscall=none"
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# enable transparent hugepages
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"transparent_hugepage=always"
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# disable debugfs
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"debugfs=off"
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# clear mlocked memory in case the program crashes
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"init_mlocked_on_free=1"
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];
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boot.kernel.sysctl = {
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# disable automatic loading of TTY line disciplines
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"dev.tty.ldisc_autoload" = 0;
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"kernel.ftrace_enabled" = lib.mkDefault false;
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# disable first 64 KiB of virtual memory for allocation
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"vm.mmap_min_addr" = 65536;
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# increase ASLR randomisation
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"vm.mmap_rnd_bits" = 32;
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"vm.mmap_rnd_compat_bits" = 16;
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# restrict ptrace()
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"kernel.yama.ptrace_scope" = 1;
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# hide kernel memory addresses
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"kernel.kptr_restrict" = 2;
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# enable hardened eBPF JIT
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"net.core.bpf_jit_enable" = 1;
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"net.core.bpf_jit_harden" = 1;
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# Dirty page cache ratio
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"vm.dirty_background_ratio" = 3;
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"vm.dirty_ratio" = 6;
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# Hide kptrs even for processes with CAP_SYSLOG
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"kernel.kptr_restrict" = lib.mkOverride 500 2;
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};
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}
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# references:
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# - https://github.com/NixOS/nixpkgs/blob/e6db435973160591fe7348876a5567c729495175/pkgs/os-specific/linux/kernel/hardened/config.nix
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# - https://nixos.wiki/wiki/Linux_kernel#Custom_configuration
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# - https://kspp.github.io/
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# - linux src/arch/x86/configs/hardening.config and src/kernel/configs/hardening.config
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# - trial and error
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# - illdef
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3
kernel/latest.nix
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3
kernel/latest.nix
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@ -0,0 +1,3 @@
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{lib, config, pkgs, ...}: config.lyn.lib.mkLocalModule ./latest.nix "latest linux kernel" {
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boot.kernelPackages = pkgs.linuxPackages_latest;
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}
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@ -1,23 +1,71 @@
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{lib, config, ...}: {
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lib.mkLocalModule = pathInterpolation: optDesc: config: let
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#example_input = ./some/subdir/MARKER/a/b/c/d/e/f/g;
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marker = "local-modules";
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splitAfterMarker = marker: input: builtins.foldl' (acc: new:
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{lib, ...}: { config.lyn.lib = rec {
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/**
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Split a string, and return all elements after a marker.
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# Example
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```
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splitAfterMarker "/" "modules" /home/user/flake/modules/abc/def
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== ["abc" "def"]
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```
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*/
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splitAfterMarker = splitter: marker: input: builtins.foldl' (acc: new:
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if acc == false then # marker not found yet
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if new == marker then [] else acc
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else # marker found
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if builtins.typeOf new == "string"
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then acc ++ [new]
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else acc
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) false (builtins.split "/" (builtins.toString input));
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path = splitAfterMarker marker pathInterpolation;
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inputs = {
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#optDesc = "enable this";
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inherit optDesc: config;
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};
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if new == marker then [] /* marker found */ else false
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else acc ++ [new] # marker already found, add to output list
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) false (lib.splitString splitter input);
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/**
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Make a Nix module, with its attrpath being the local path
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relative to a marker directory. Accepts a prefix, and removes `.nix` file endings.
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# Example
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```
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mkLocalModuleMarker "modules" ["myModules" "abc"] ./current-file.nix "enable something" {}
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{ myModules.abc.current.file.path.current-file.enable = true; }
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```
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*/
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mkLocalModuleMarker = marker: prefix: currentPath: optDesc: moduleConfig: let
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normalizedPath = removeSuffix ".nix" (builtins.toString currentPath);
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attrPath = prefix ++ (splitAfterMarker "/" marker normalizedPath);
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mod = {config, ...}: {
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options = lib.setAttrsByPath path (lib.mkEnableOption inputs.optDesc);
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config = lib.mkIf (lib.getAttrByPath path config) inputs.config;
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options = lib.setAttrsByPath attrPath (lib.mkEnableOption optDesc);
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config = lib.mkIf (lib.getAttrByPath attrPath config) moduleConfig;
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};
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in mod;
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}
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/**
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Find a folder or a parent folder containing a file.
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# Example
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```
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findFolderWithFile "flake.nix" ./.
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== /home/user/flake/
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```
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*/
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findFolderWithFile = file: arg:
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if builtins.pathExists (arg + "/" + file) then arg
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else if arg == /. then throw "could not find folder containing ${file}"
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else findRoot file (arg + "/..");
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/**
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Shorthand for mkLocalModuleMarker, setting marker to your flake and prefix to l.
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*/
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mkLocalModule = path: mkLocalModuleMarker (findFolderWithFile "flake.nix" path) ["lyn"] path;
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};}
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# foldl' op nul [x0 x1 x2 ...] = op (op (op nul x0) x1) x2) .... For example, foldl' (x: y: x + y) 0 [1 2 3]
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# input = /home/alina/flake/desktop/common
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# options.desktop.common
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# input' = /nix/store/aaa-flake/desktop/common
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# foldl' (split "/" input)
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# marker = flake
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# foldl' ([home alina flake modules audio.nix ])
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# acc = false false [] [modules] [modules audio.nix]
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# | ^ marker found
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# | marker not found yet
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# $ echo "abc\ndef" > readme
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# readPathsFromFile "readme" == [./abc ./def]
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