92abc4c610
AppArmor only requires a few patches to the 3.2 and 3.4 kernels in order to work properly (with the minor catch grsecurity -stable includes the 3.2 patches.) This adds them to the kernel builds by default, removes features.apparmor (since it's always true) and makes it the default MAC system. Signed-off-by: Austin Seipp <aseipp@pobox.com>
441 lines
16 KiB
Nix
441 lines
16 KiB
Nix
{ config, lib, pkgs, ... }:
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with lib;
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let
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cfg = config.security.grsecurity;
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mkKernel = kernel: patch:
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assert patch.kversion == kernel.version;
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{ inherit kernel patch;
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inherit (patch) grversion revision;
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};
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stable-patch = with pkgs.kernelPatches;
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if cfg.vserver then grsecurity_vserver else grsecurity_stable;
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stableKernel = mkKernel pkgs.linux_3_2 stable-patch;
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testKernel = mkKernel pkgs.linux_3_14 pkgs.kernelPatches.grsecurity_unstable;
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## -- grsecurity configuration -----------------------------------------------
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grsecPrioCfg =
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if cfg.config.priority == "security" then
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"GRKERNSEC_CONFIG_PRIORITY_SECURITY y"
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else
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"GRKERNSEC_CONFIG_PRIORITY_PERF y";
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grsecSystemCfg =
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if cfg.config.system == "desktop" then
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"GRKERNSEC_CONFIG_DESKTOP y"
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else
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"GRKERNSEC_CONFIG_SERVER y";
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grsecVirtCfg =
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if cfg.config.virtualisationConfig == "none" then
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"GRKERNSEC_CONFIG_VIRT_NONE y"
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else if cfg.config.virtualisationConfig == "host" then
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"GRKERNSEC_CONFIG_VIRT_HOST y"
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else
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"GRKERNSEC_CONFIG_VIRT_GUEST y";
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grsecHwvirtCfg = if cfg.config.virtualisationConfig == "none" then "" else
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if cfg.config.hardwareVirtualisation == true then
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"GRKERNSEC_CONFIG_VIRT_EPT y"
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else
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"GRKERNSEC_CONFIG_VIRT_SOFT y";
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grsecVirtswCfg =
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let virtCfg = opt: "GRKERNSEC_CONFIG_VIRT_"+opt+" y";
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in
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if cfg.config.virtualisationConfig == "none" then ""
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else if cfg.config.virtualisationSoftware == "xen" then virtCfg "XEN"
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else if cfg.config.virtualisationSoftware == "kvm" then virtCfg "KVM"
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else if cfg.config.virtualisationSoftware == "vmware" then virtCfg "VMWARE"
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else virtCfg "VIRTUALBOX";
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grsecMainConfig = if cfg.config.mode == "custom" then "" else ''
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GRKERNSEC_CONFIG_AUTO y
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${grsecPrioCfg}
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${grsecSystemCfg}
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${grsecVirtCfg}
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${grsecHwvirtCfg}
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${grsecVirtswCfg}
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'';
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grsecConfig =
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let boolToKernOpt = b: if b then "y" else "n";
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# Disable RANDSTRUCT under virtualbox, as it has some kind of
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# breakage with the vbox guest drivers
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randstruct = optionalString config.services.virtualbox.enable
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"GRKERNSEC_RANDSTRUCT n";
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# Disable restricting links under the testing kernel, as something
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# has changed causing it to fail miserably during boot.
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restrictLinks = optionalString cfg.testing
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"GRKERNSEC_LINK n";
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in ''
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GRKERNSEC y
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${grsecMainConfig}
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${if cfg.config.restrictProc then
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"GRKERNSEC_PROC_USER y"
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else
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optionalString cfg.config.restrictProcWithGroup ''
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GRKERNSEC_PROC_USERGROUP y
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GRKERNSEC_PROC_GID ${toString cfg.config.unrestrictProcGid}
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''
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}
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GRKERNSEC_SYSCTL ${boolToKernOpt cfg.config.sysctl}
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GRKERNSEC_CHROOT_CHMOD ${boolToKernOpt cfg.config.denyChrootChmod}
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GRKERNSEC_NO_RBAC ${boolToKernOpt cfg.config.disableRBAC}
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${randstruct}
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${restrictLinks}
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${cfg.config.kernelExtraConfig}
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'';
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## -- grsecurity kernel packages ---------------------------------------------
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localver = grkern:
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"-grsec" + optionalString cfg.config.verboseVersion
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"-${grkern.grversion}-${grkern.revision}";
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grsecurityOverrider = args: grkern: {
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# Apparently as of gcc 4.6, gcc-plugin headers (which are needed by PaX plugins)
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# include libgmp headers, so we need these extra tweaks
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buildInputs = args.buildInputs ++ [ pkgs.gmp ];
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preConfigure = ''
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${args.preConfigure or ""}
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sed -i 's|-I|-I${pkgs.gmp}/include -I|' scripts/gcc-plugin.sh
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sed -i 's|HOST_EXTRACFLAGS +=|HOST_EXTRACFLAGS += -I${pkgs.gmp}/include|' tools/gcc/Makefile
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sed -i 's|HOST_EXTRACXXFLAGS +=|HOST_EXTRACXXFLAGS += -I${pkgs.gmp}/include|' tools/gcc/Makefile
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rm localversion-grsec
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echo ${localver grkern} > localversion-grsec
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'';
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};
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mkGrsecPkg = grkern:
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let kernelPkg = lowPrio (overrideDerivation (grkern.kernel.override (args: {
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kernelPatches = args.kernelPatches ++ [ grkern.patch pkgs.kernelPatches.grsec_fix_path ];
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argsOverride = {
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modDirVersion = "${grkern.kernel.modDirVersion}${localver grkern}";
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};
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extraConfig = grsecConfig;
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})) (args: grsecurityOverrider args grkern));
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in pkgs.linuxPackagesFor kernelPkg (mkGrsecPkg grkern);
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grsecPackage = mkGrsecPkg (if cfg.stable then stableKernel else testKernel);
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in
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{
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options = {
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security.grsecurity = {
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enable = mkOption {
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type = types.bool;
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default = false;
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description = ''
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Enable grsecurity support. This enables advanced exploit
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hardening for the Linux kernel, and adds support for
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administrative Role-Based Acess Control (RBAC) via
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<literal>gradm</literal>. It also includes traditional
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utilities for PaX.
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'';
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};
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stable = mkOption {
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type = types.bool;
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default = false;
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description = ''
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Enable the stable grsecurity patch, based on Linux 3.2.
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'';
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};
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vserver = mkOption {
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type = types.bool;
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default = false;
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description = ''
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Enable the stable grsecurity/vserver patches, based on Linux 3.2.
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'';
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};
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testing = mkOption {
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type = types.bool;
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default = false;
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description = ''
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Enable the testing grsecurity patch, based on Linux 3.13.
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'';
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};
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config = {
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mode = mkOption {
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type = types.str;
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default = "auto";
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example = "custom";
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description = ''
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grsecurity configuration mode. This specifies whether
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grsecurity is auto-configured or otherwise completely
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manually configured. Can either by
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<literal>custom</literal> or <literal>auto</literal>.
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<literal>auto</literal> is recommended.
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'';
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};
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priority = mkOption {
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type = types.str;
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default = "security";
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example = "performance";
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description = ''
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grsecurity configuration priority. This specifies whether
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the kernel configuration should emphasize speed or
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security. Can either by <literal>security</literal> or
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<literal>performance</literal>.
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'';
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};
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system = mkOption {
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type = types.str;
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default = "";
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example = "desktop";
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description = ''
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grsecurity system configuration. This specifies whether
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the kernel configuration should be suitable for a Desktop
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or a Server. Can either by <literal>server</literal> or
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<literal>desktop</literal>.
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'';
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};
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virtualisationConfig = mkOption {
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type = types.str;
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default = "none";
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example = "host";
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description = ''
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grsecurity virtualisation configuration. This specifies
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the virtualisation role of the machine - that is, whether
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it will be a virtual machine guest, a virtual machine
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host, or neither. Can be one of <literal>none</literal>,
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<literal>host</literal>, or <literal>guest</literal>.
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'';
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};
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hardwareVirtualisation = mkOption {
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type = types.nullOr types.bool;
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default = null;
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example = true;
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description = ''
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grsecurity hardware virtualisation configuration. Set to
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<literal>true</literal> if your machine supports hardware
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accelerated virtualisation.
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'';
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};
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virtualisationSoftware = mkOption {
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type = types.str;
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default = "";
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example = "kvm";
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description = ''
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grsecurity virtualisation software. Set this to the
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specified virtual machine technology if the machine is
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running as a guest, or a host.
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Can be one of <literal>kvm</literal>,
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<literal>xen</literal>, <literal>vmware</literal> or
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<literal>virtualbox</literal>.
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'';
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};
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sysctl = mkOption {
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type = types.bool;
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default = false;
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description = ''
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If true, then set <literal>GRKERN_SYSCTL y</literal>. If
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enabled then grsecurity can be controlled using sysctl
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(and turned off). You are advised to *never* enable this,
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but if you do, make sure to always set the sysctl
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<literal>kernel.grsecurity.grsec_lock</literal> to
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non-zero as soon as all sysctl options are set. *THIS IS
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EXTREMELY IMPORTANT*!
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If disabled, this also turns off the
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<literal>systemd-sysctl</literal> service.
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'';
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};
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denyChrootChmod = mkOption {
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type = types.bool;
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default = false;
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description = ''
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If true, then set <literal>GRKERN_CHROOT_CHMOD
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y</literal>. If enabled, this denies processes inside a
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chroot from setting the suid or sgid bits using
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<literal>chmod</literal> or <literal>fchmod</literal>.
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By default this protection is disabled - it makes it
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impossible to use Nix to build software on your system,
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which is what most users want.
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If you are using NixOps to deploy your software to a
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remote machine, you're encouraged to enable this as you
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won't need to compile code.
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'';
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};
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restrictProc = mkOption {
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type = types.bool;
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default = false;
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description = ''
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If true, then set <literal>GRKERN_PROC_USER
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y</literal>. This restricts non-root users to only viewing
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their own processes and restricts network-related
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information, kernel symbols, and module information.
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'';
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};
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restrictProcWithGroup = mkOption {
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type = types.bool;
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default = true;
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description = ''
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If true, then set <literal>GRKERN_PROC_USERGROUP
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y</literal>. This is similar to
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<literal>restrictProc</literal> except it allows a special
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group (specified by <literal>unrestrictProcGid</literal>)
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to still access otherwise classified information in
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<literal>/proc</literal>.
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'';
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};
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unrestrictProcGid = mkOption {
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type = types.int;
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default = config.ids.gids.grsecurity;
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description = ''
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If set, specifies a GID which is exempt from
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<literal>/proc</literal> restrictions (set by
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<literal>GRKERN_PROC_USERGROUP</literal>). By default,
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this is set to the GID for <literal>grsecurity</literal>,
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a predefined NixOS group, which the
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<literal>root</literal> account is a member of. You may
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conveniently add other users to this group if you need
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access to <literal>/proc</literal>
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'';
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};
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disableRBAC = mkOption {
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type = types.bool;
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default = false;
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description = ''
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If true, then set <literal>GRKERN_NO_RBAC
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y</literal>. This disables the
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<literal>/dev/grsec</literal> device, which in turn
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disables the RBAC system (and <literal>gradm</literal>).
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'';
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};
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verboseVersion = mkOption {
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type = types.bool;
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default = false;
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description = "Use verbose version in kernel localversion.";
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};
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kernelExtraConfig = mkOption {
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type = types.str;
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default = "";
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description = "Extra kernel configuration parameters.";
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};
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};
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};
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};
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config = mkIf cfg.enable {
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assertions =
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[ { assertion = cfg.stable || cfg.testing;
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message = ''
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If grsecurity is enabled, you must select either the
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stable patch (with kernel 3.2), or the testing patch (with
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kernel 3.13) to continue.
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'';
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}
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{ assertion = (cfg.stable -> !cfg.testing) || (cfg.testing -> !cfg.stable);
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message = ''
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You must select either the stable or testing patch, not
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both.
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'';
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}
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{ assertion = (cfg.testing -> !cfg.vserver);
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message = "The vserver patches are only supported in the stable kernel.";
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}
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{ assertion = (cfg.config.restrictProc -> !cfg.config.restrictProcWithGroup) ||
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(cfg.config.restrictProcWithGroup -> !cfg.config.restrictProc);
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message = "You cannot enable both restrictProc and restrictProcWithGroup";
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}
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{ assertion = config.boot.kernelPackages.kernel.features ? grsecurity
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&& config.boot.kernelPackages.kernel.features.grsecurity;
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message = "grsecurity enabled, but kernel doesn't have grsec support";
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}
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{ assertion = elem cfg.config.mode [ "auto" "custom" ];
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message = "grsecurity mode must either be 'auto' or 'custom'.";
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}
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{ assertion = cfg.config.mode == "auto" -> elem cfg.config.system [ "desktop" "server" ];
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message = "when using auto grsec mode, system must be either 'desktop' or 'server'";
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}
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{ assertion = cfg.config.mode == "auto" -> elem cfg.config.priority [ "performance" "security" ];
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message = "when using auto grsec mode, priority must be 'performance' or 'security'.";
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}
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{ assertion = cfg.config.mode == "auto" -> elem cfg.config.virtualisationConfig [ "host" "guest" "none" ];
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message = "when using auto grsec mode, 'virt' must be 'host', 'guest' or 'none'.";
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}
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{ assertion = (cfg.config.mode == "auto" && (elem cfg.config.virtualisationConfig [ "host" "guest" ])) ->
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cfg.config.hardwareVirtualisation != null;
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message = "when using auto grsec mode with virtualisation, you must specify if your hardware has virtualisation extensions";
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}
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{ assertion = (cfg.config.mode == "auto" && (elem cfg.config.virtualisationConfig [ "host" "guest" ])) ->
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elem cfg.config.virtualisationSoftware [ "kvm" "xen" "virtualbox" "vmware" ];
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message = "virtualisation software must be 'kvm', 'xen', 'vmware' or 'virtualbox'";
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}
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];
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systemd.services.grsec-lock = mkIf cfg.config.sysctl {
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description = "grsecurity sysctl-lock Service";
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requires = [ "sysctl.service" ];
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wantedBy = [ "multi-user.target" ];
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serviceConfig.Type = "oneshot";
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serviceConfig.RemainAfterExit = "yes";
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script = ''
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locked=`cat /proc/sys/kernel/grsecurity/grsec_lock`
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if [ "$locked" == "0" ]; then
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echo 1 > /proc/sys/kernel/grsecurity/grsec_lock
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echo grsecurity sysctl lock - enabled
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else
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echo grsecurity sysctl lock already enabled - doing nothing
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fi
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'';
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};
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# systemd.services.grsec-learn = {
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# description = "grsecurity learning Service";
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# wantedBy = [ "local-fs.target" ];
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# serviceConfig = {
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# Type = "oneshot";
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# RemainAfterExit = "yes";
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# ExecStart = "${pkgs.gradm}/sbin/gradm -VFL /etc/grsec/learning.logs";
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# ExecStop = "${pkgs.gradm}/sbin/gradm -D";
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# };
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# };
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system.activationScripts.grsec =
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''
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mkdir -p /etc/grsec
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if [ ! -f /etc/grsec/learn_config ]; then
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cp ${pkgs.gradm}/etc/grsec/learn_config /etc/grsec
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fi
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if [ ! -f /etc/grsec/policy ]; then
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cp ${pkgs.gradm}/etc/grsec/policy /etc/grsec
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fi
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chmod -R 0600 /etc/grsec
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'';
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# Enable AppArmor, gradm udev rules, and utilities
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security.apparmor.enable = true;
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boot.kernelPackages = grsecPackage;
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services.udev.packages = [ pkgs.gradm ];
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environment.systemPackages = [ pkgs.gradm pkgs.paxctl pkgs.pax-utils ];
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};
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}
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