1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
|
{ config, lib, pkgs, ... }:
let
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
{
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 ];
}
|