···
{ config, lib, pkgs, ... }:
+
inherit (lib) mkOption types;
cfg = config.security.dhparams;
+
bitType = types.addCheck types.int (b: b >= 16) // {
+
description = "integer of at least 16 bits";
+
paramsSubmodule = { name, config, ... }: {
+
options.bits = mkOption {
+
default = cfg.defaultBitSize;
+
The bit size for the prime that is used during a Diffie-Hellman
+
options.path = mkOption {
+
The resulting path of the generated Diffie-Hellman parameters
+
file for other services to reference. This could be either a
+
store path or a file inside the directory specified by
+
<option>security.dhparams.path</option>.
+
generated = pkgs.runCommand "dhparams-${name}.pem" {
+
nativeBuildInputs = [ pkgs.openssl ];
+
} "openssl dhparam -out \"$out\" ${toString config.bits}";
+
in if cfg.stateful then "${cfg.path}/${name}.pem" else generated;
+
Whether to generate new DH params and clean up old DH params.
+
coerce = bits: { inherit bits; };
+
in attrsOf (coercedTo int coerce (submodule paramsSubmodule));
+
example = lib.literalExample "{ nginx.bits = 3072; }";
+
Diffie-Hellman parameters to generate.
+
The value is the size (in bits) of the DH params to generate. The
+
generated DH params path can be found in
+
<literal>config.security.dhparams.params.<replaceable>name</replaceable>.path</literal>.
+
<note><para>The name of the DH params is taken as being the name of
+
the service it serves and the params will be generated before the
+
said service is started.</para></note>
+
<warning><para>If you are removing all dhparams from this list, you
+
have to leave <option>security.dhparams.enable</option> for at
+
least one activation in order to have them be cleaned up. This also
+
means if you rollback to a version without any dhparams the
+
existing ones won't be cleaned up. Of course this only applies if
+
<option>security.dhparams.stateful</option> is
+
<literal>true</literal>.</para></warning>
+
<note><title>For module implementers:</title><para>It's recommended
+
to not set a specific bit size here, so that users can easily
+
override this by setting
+
<option>security.dhparams.defaultBitSize</option>.</para></note>
+
Whether generation of Diffie-Hellman parameters should be stateful or
+
not. If this is enabled, PEM-encoded files for Diffie-Hellman
+
parameters are placed in the directory specified by
+
<option>security.dhparams.path</option>. Otherwise the files are
+
created within the Nix store.
+
<note><para>If this is <literal>false</literal> the resulting store
+
path will be non-deterministic and will be rebuilt every time the
+
<package>openssl</package> package changes.</para></note>
+
defaultBitSize = mkOption {
+
This allows to override the default bit size for all of the
+
Diffie-Hellman parameters set in
+
<option>security.dhparams.params</option>.
default = "/var/lib/dhparams";
+
Path to the directory in which Diffie-Hellman parameters will be
+
stored. This only is relevant if
+
<option>security.dhparams.stateful</option> is
+
<literal>true</literal>.
+
config = lib.mkIf (cfg.enable && cfg.stateful) {
+
description = "Clean Up Old Diffie-Hellman Parameters";
+
# Clean up even when no DH params is set
+
wantedBy = [ "multi-user.target" ];
+
serviceConfig.RemainAfterExit = true;
serviceConfig.Type = "oneshot";
+
if [ ! -d ${cfg.path} ]; then
+
for file in ${cfg.path}/*; do
+
if [ ! -f "$file" ]; then
+
${lib.concatStrings (lib.mapAttrsToList (name: { bits, path, ... }: ''
+
if [ "$file" = ${lib.escapeShellArg path} ] && \
+
${pkgs.openssl}/bin/openssl dhparam -in "$file" -text \
+
| head -n 1 | grep "(${toString bits} bit)" > /dev/null; then
+
# TODO: Ideally this would be removing the *former* cfg.path, though
+
# this does not seem really important as changes to it are quite
+
rmdir --ignore-fail-on-non-empty ${cfg.path}
+
} // lib.mapAttrs' (name: { bits, path, ... }: lib.nameValuePair "dhparams-gen-${name}" {
+
description = "Generate Diffie-Hellman Parameters for ${name}";
+
after = [ "dhparams-init.service" ];
+
before = [ "${name}.service" ];
+
wantedBy = [ "multi-user.target" ];
+
unitConfig.ConditionPathExists = "!${path}";
+
serviceConfig.Type = "oneshot";
+
mkdir -p ${lib.escapeShellArg cfg.path}
+
${pkgs.openssl}/bin/openssl dhparam -out ${lib.escapeShellArg path} \