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author | Julien Moutinho <julm+nixpkgs@sourcephile.fr> | 2020-10-18 15:36:24 +0200 |
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committer | Julien Moutinho <julm+nixpkgs@sourcephile.fr> | 2021-04-23 07:17:55 +0200 |
commit | 05d334cfe265f021b16c41375e3e5a4c4a07fc74 (patch) | |
tree | 0d00c946f6f9ed0492ec74725261a44d59bfd067 /nixos/modules/security/apparmor.nix | |
parent | d239bc36439f4f1457c5c70ad59f8a737989d79a (diff) | |
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Revert "Revert "apparmor: fix and improve the service""
This reverts commit 420f89ceb267b461eed5d025b6c3c0e57703cc5c.
Diffstat (limited to 'nixos/modules/security/apparmor.nix')
-rw-r--r-- | nixos/modules/security/apparmor.nix | 241 |
1 files changed, 190 insertions, 51 deletions
diff --git a/nixos/modules/security/apparmor.nix b/nixos/modules/security/apparmor.nix index cfc65b347bc..3bf1e0fefc3 100644 --- a/nixos/modules/security/apparmor.nix +++ b/nixos/modules/security/apparmor.nix @@ -1,59 +1,198 @@ { config, lib, pkgs, ... }: let - inherit (lib) mkIf mkOption types concatMapStrings; + inherit (builtins) attrNames head map match readFile; + inherit (lib) types; + inherit (config.environment) etc; cfg = config.security.apparmor; + mkDisableOption = name: lib.mkEnableOption name // { + default = true; + example = false; + }; + enabledPolicies = lib.filterAttrs (n: p: p.enable) cfg.policies; in { - options = { - security.apparmor = { - enable = mkOption { - type = types.bool; - default = false; - description = "Enable the AppArmor Mandatory Access Control system."; - }; - profiles = mkOption { - type = types.listOf types.path; - default = []; - description = "List of files containing AppArmor profiles."; - }; - packages = mkOption { - type = types.listOf types.package; - default = []; - description = "List of packages to be added to apparmor's include path"; - }; - }; - }; - - config = mkIf cfg.enable { - environment.systemPackages = [ pkgs.apparmor-utils ]; - - boot.kernelParams = [ "apparmor=1" "security=apparmor" ]; - - systemd.services.apparmor = let - paths = concatMapStrings (s: " -I ${s}/etc/apparmor.d") - ([ pkgs.apparmor-profiles ] ++ cfg.packages); - in { - after = [ "local-fs.target" ]; - before = [ "sysinit.target" ]; - wantedBy = [ "multi-user.target" ]; - unitConfig = { - DefaultDependencies = "no"; - }; - serviceConfig = { - Type = "oneshot"; - RemainAfterExit = "yes"; - ExecStart = map (p: - ''${pkgs.apparmor-parser}/bin/apparmor_parser -rKv ${paths} "${p}"'' - ) cfg.profiles; - ExecStop = map (p: - ''${pkgs.apparmor-parser}/bin/apparmor_parser -Rv "${p}"'' - ) cfg.profiles; - ExecReload = map (p: - ''${pkgs.apparmor-parser}/bin/apparmor_parser --reload ${paths} "${p}"'' - ) cfg.profiles; - }; - }; - }; + imports = [ + (lib.mkRenamedOptionModule [ "security" "virtualization" "flushL1DataCache" ] [ "security" "virtualisation" "flushL1DataCache" ]) + (lib.mkRemovedOptionModule [ "security" "apparmor" "confineSUIDApplications" ] "Please use the new options: `security.apparmor.policies.<policy>.enable'.") + (lib.mkRemovedOptionModule [ "security" "apparmor" "profiles" ] "Please use the new option: `security.apparmor.policies'.") + apparmor/includes.nix + apparmor/profiles.nix + ]; + + options = { + security.apparmor = { + enable = lib.mkEnableOption ''the AppArmor Mandatory Access Control system. + + If you're enabling this module on a running system, + note that a reboot will be required to activate AppArmor in the kernel. + + Also, beware that enabling this module will by default + try to kill unconfined but confinable running processes, + in order to obtain a confinement matching what is declared in the NixOS configuration. + This will happen when upgrading to a NixOS revision + introducing an AppArmor profile for the executable of a running process. + This is because enabling an AppArmor profile for an executable + can only confine new or already confined processes of that executable, + but leaves already running processes unconfined. + Set <link linkend="opt-security.apparmor.killUnconfinedConfinables">killUnconfinedConfinables</link> + to <literal>false</literal> if you prefer to leave those processes running''; + policies = lib.mkOption { + description = '' + AppArmor policies. + ''; + type = types.attrsOf (types.submodule ({ name, config, ... }: { + options = { + enable = mkDisableOption "loading of the profile into the kernel"; + enforce = mkDisableOption "enforcing of the policy or only complain in the logs"; + profile = lib.mkOption { + description = "The policy of the profile."; + type = types.lines; + apply = pkgs.writeText name; + }; + }; + })); + default = {}; + }; + includes = lib.mkOption { + type = types.attrsOf types.lines; + default = {}; + description = '' + List of paths to be added to AppArmor's searched paths + when resolving <literal>include</literal> directives. + ''; + apply = lib.mapAttrs pkgs.writeText; + }; + packages = lib.mkOption { + type = types.listOf types.package; + default = []; + description = "List of packages to be added to AppArmor's include path"; + }; + enableCache = lib.mkEnableOption ''caching of AppArmor policies + in <literal>/var/cache/apparmor/</literal>. + + Beware that AppArmor policies almost always contain Nix store paths, + and thus produce at each change of these paths + a new cached version accumulating in the cache''; + killUnconfinedConfinables = mkDisableOption ''killing of processes + which have an AppArmor profile enabled + (in <link linkend="opt-security.apparmor.policies">policies</link>) + but are not confined (because AppArmor can only confine new processes). + Beware that due to a current limitation of AppArmor, + only profiles with exact paths (and no name) can enable such kills''; + }; + }; + + config = lib.mkIf cfg.enable { + assertions = map (policy: + { assertion = match ".*/.*" policy == null; + message = "`security.apparmor.policies.\"${policy}\"' must not contain a slash."; + # Because, for instance, aa-remove-unknown uses profiles_names_list() in rc.apparmor.functions + # which does not recurse into sub-directories. + } + ) (attrNames cfg.policies); + + environment.systemPackages = [ pkgs.apparmor-utils ]; + environment.etc."apparmor.d".source = pkgs.linkFarm "apparmor.d" ( + # It's important to put only enabledPolicies here and not all cfg.policies + # because aa-remove-unknown reads profiles from all /etc/apparmor.d/* + lib.mapAttrsToList (name: p: {inherit name; path=p.profile;}) enabledPolicies ++ + lib.mapAttrsToList (name: path: {inherit name path;}) cfg.includes + ); + environment.etc."apparmor/parser.conf".text = '' + ${if cfg.enableCache then "write-cache" else "skip-cache"} + cache-loc /var/cache/apparmor + Include /etc/apparmor.d + '' + + lib.concatMapStrings (p: "Include ${p}/etc/apparmor.d\n") cfg.packages; + # For aa-logprof + environment.etc."apparmor/apparmor.conf".text = '' + ''; + # For aa-logprof + environment.etc."apparmor/severity.db".source = pkgs.apparmor-utils + "/etc/apparmor/severity.db"; + environment.etc."apparmor/logprof.conf".text = '' + [settings] + # /etc/apparmor.d/ is read-only on NixOS + profiledir = /var/cache/apparmor/logprof + inactive_profiledir = /etc/apparmor.d/disable + # Use: journalctl -b --since today --grep audit: | aa-logprof + logfiles = /dev/stdin + + parser = ${pkgs.apparmor-parser}/bin/apparmor_parser + ldd = ${pkgs.glibc.bin}/bin/ldd + logger = ${pkgs.utillinux}/bin/logger + + # customize how file ownership permissions are presented + # 0 - off + # 1 - default of what ever mode the log reported + # 2 - force the new permissions to be user + # 3 - force all perms on the rule to be user + default_owner_prompt = 1 + + custom_includes = /etc/apparmor.d ${lib.concatMapStringsSep " " (p: "${p}/etc/apparmor.d") cfg.packages} + + [qualifiers] + ${pkgs.runtimeShell} = icnu + ${pkgs.bashInteractive}/bin/sh = icnu + ${pkgs.bashInteractive}/bin/bash = icnu + '' + head (match "^.*\\[qualifiers](.*)" # Drop the original [settings] section. + (readFile "${pkgs.apparmor-utils}/etc/apparmor/logprof.conf")); + + boot.kernelParams = [ "apparmor=1" "security=apparmor" ]; + + systemd.services.apparmor = { + after = [ + "local-fs.target" + "systemd-journald-audit.socket" + ]; + before = [ "sysinit.target" ]; + wantedBy = [ "multi-user.target" ]; + unitConfig = { + Description="Load AppArmor policies"; + DefaultDependencies = "no"; + ConditionSecurity = "apparmor"; + }; + # Reloading instead of restarting enables to load new AppArmor profiles + # without necessarily restarting all services which have Requires=apparmor.service + reloadIfChanged = true; + restartTriggers = [ + etc."apparmor/parser.conf".source + etc."apparmor.d".source + ]; + serviceConfig = let + killUnconfinedConfinables = pkgs.writeShellScript "apparmor-kill" '' + set -eu + ${pkgs.apparmor-utils}/bin/aa-status --json | + ${pkgs.jq}/bin/jq --raw-output '.processes | .[] | .[] | select (.status == "unconfined") | .pid' | + xargs --verbose --no-run-if-empty --delimiter='\n' \ + kill + ''; + commonOpts = p: "--verbose --show-cache ${lib.optionalString (!p.enforce) "--complain "}${p.profile}"; + in { + Type = "oneshot"; + RemainAfterExit = "yes"; + ExecStartPre = "${pkgs.apparmor-utils}/bin/aa-teardown"; + ExecStart = lib.mapAttrsToList (n: p: "${pkgs.apparmor-parser}/bin/apparmor_parser --add ${commonOpts p}") enabledPolicies; + ExecStartPost = lib.optional cfg.killUnconfinedConfinables killUnconfinedConfinables; + ExecReload = + # Add or replace into the kernel profiles in enabledPolicies + # (because AppArmor can do that without stopping the processes already confined). + lib.mapAttrsToList (n: p: "${pkgs.apparmor-parser}/bin/apparmor_parser --replace ${commonOpts p}") enabledPolicies ++ + # Remove from the kernel any profile whose name is not + # one of the names within the content of the profiles in enabledPolicies + # (indirectly read from /etc/apparmor.d/*, without recursing into sub-directory). + # Note that this does not remove profiles dynamically generated by libvirt. + [ "${pkgs.apparmor-utils}/bin/aa-remove-unknown" ] ++ + # Optionaly kill the processes which are unconfined but now have a profile loaded + # (because AppArmor can only start to confine new processes). + lib.optional cfg.killUnconfinedConfinables killUnconfinedConfinables; + ExecStop = "${pkgs.apparmor-utils}/bin/aa-teardown"; + CacheDirectory = [ "apparmor" "apparmor/logprof" ]; + CacheDirectoryMode = "0700"; + }; + }; + }; + + meta.maintainers = with lib.maintainers; [ julm ]; } |