nixpkgs/nixos/modules/security/acme.nix
2019-08-31 10:04:20 +02:00

313 lines
11 KiB
Nix

{ config, lib, pkgs, ... }:
with lib;
let
cfg = config.security.acme;
certOpts = { name, ... }: {
options = {
webroot = mkOption {
type = types.str;
example = "/var/lib/acme/acme-challenges";
description = ''
Where the webroot of the HTTP vhost is located.
<filename>.well-known/acme-challenge/</filename> directory
will be created below the webroot if it doesn't exist.
<literal>http://example.org/.well-known/acme-challenge/</literal> must also
be available (notice unencrypted HTTP).
'';
};
domain = mkOption {
type = types.str;
default = name;
description = "Domain to fetch certificate for (defaults to the entry name)";
};
email = mkOption {
type = types.nullOr types.str;
default = null;
description = "Contact email address for the CA to be able to reach you.";
};
user = mkOption {
type = types.str;
default = "root";
description = "User running the ACME client.";
};
group = mkOption {
type = types.str;
default = "root";
description = "Group running the ACME client.";
};
allowKeysForGroup = mkOption {
type = types.bool;
default = false;
description = ''
Give read permissions to the specified group
(<option>security.acme.cert.&lt;name&gt;.group</option>) to read SSL private certificates.
'';
};
postRun = mkOption {
type = types.lines;
default = "";
example = "systemctl reload nginx.service";
description = ''
Commands to run after new certificates go live. Typically
the web server and other servers using certificates need to
be reloaded.
Executed in the same directory with the new certificate.
'';
};
plugins = mkOption {
type = types.listOf (types.enum [
"cert.der" "cert.pem" "chain.pem" "external.sh"
"fullchain.pem" "full.pem" "key.der" "key.pem" "account_key.json"
]);
default = [ "fullchain.pem" "full.pem" "key.pem" "account_key.json" ];
description = ''
Plugins to enable. With default settings simp_le will
store public certificate bundle in <filename>fullchain.pem</filename>,
private key in <filename>key.pem</filename> and those two previous
files combined in <filename>full.pem</filename> in its state directory.
'';
};
directory = mkOption {
type = types.str;
readOnly = true;
default = "/var/lib/acme/${name}";
description = "Directory where certificate and other state is stored.";
};
extraDomains = mkOption {
type = types.attrsOf (types.nullOr types.str);
default = {};
example = literalExample ''
{
"example.org" = "/srv/http/nginx";
"mydomain.org" = null;
}
'';
description = ''
A list of extra domain names, which are included in the one certificate to be issued, with their
own server roots if needed.
'';
};
};
};
in
{
###### interface
options = {
security.acme = {
validMin = mkOption {
type = types.int;
default = 30 * 24 * 3600;
description = "Minimum remaining validity before renewal in seconds.";
};
renewInterval = mkOption {
type = types.str;
default = "weekly";
description = ''
Systemd calendar expression when to check for renewal. See
<citerefentry><refentrytitle>systemd.time</refentrytitle>
<manvolnum>7</manvolnum></citerefentry>.
'';
};
preliminarySelfsigned = mkOption {
type = types.bool;
default = true;
description = ''
Whether a preliminary self-signed certificate should be generated before
doing ACME requests. This can be useful when certificates are required in
a webserver, but ACME needs the webserver to make its requests.
With preliminary self-signed certificate the webserver can be started and
can later reload the correct ACME certificates.
'';
};
production = mkOption {
type = types.bool;
default = true;
description = ''
If set to true, use Let's Encrypt's production environment
instead of the staging environment. The main benefit of the
staging environment is to get much higher rate limits.
See
<literal>https://letsencrypt.org/docs/staging-environment</literal>
for more detail.
'';
};
certs = mkOption {
default = { };
type = with types; attrsOf (submodule certOpts);
description = ''
Attribute set of certificates to get signed and renewed. Creates
<literal>acme-''${cert}.{service,timer}</literal> systemd units for
each certificate defined here. Other services can add dependencies
to those units if they rely on the certificates being present,
or trigger restarts of the service if certificates get renewed.
'';
example = literalExample ''
{
"example.com" = {
webroot = "/var/www/challenges/";
email = "foo@example.com";
extraDomains = { "www.example.com" = null; "foo.example.com" = "/var/www/foo/"; };
};
"bar.example.com" = {
webroot = "/var/www/challenges/";
email = "bar@example.com";
};
}
'';
};
};
};
###### implementation
config = mkMerge [
(mkIf (cfg.certs != { }) {
systemd.services = let
services = concatLists servicesLists;
servicesLists = mapAttrsToList certToServices cfg.certs;
certToServices = cert: data:
let
lpath = "acme/${cert}";
rights = if data.allowKeysForGroup then "750" else "700";
cmdline = [ "-v" "-d" data.domain "--default_root" data.webroot "--valid_min" cfg.validMin ]
++ optionals (data.email != null) [ "--email" data.email ]
++ concatMap (p: [ "-f" p ]) data.plugins
++ concatLists (mapAttrsToList (name: root: [ "-d" (if root == null then name else "${name}:${root}")]) data.extraDomains)
++ optionals (!cfg.production) ["--server" "https://acme-staging.api.letsencrypt.org/directory"];
acmeService = {
description = "Renew ACME Certificate for ${cert}";
after = [ "network.target" "network-online.target" ];
wants = [ "network-online.target" ];
serviceConfig = {
Type = "oneshot";
SuccessExitStatus = [ "0" "1" ];
User = data.user;
Group = data.group;
PrivateTmp = true;
StateDirectory = lpath;
StateDirectoryMode = rights;
WorkingDirectory = "/var/lib/${lpath}";
ExecStart = "${pkgs.simp_le}/bin/simp_le ${escapeShellArgs cmdline}";
ExecStopPost =
let
script = pkgs.writeScript "acme-post-stop" ''
#!${pkgs.runtimeShell} -e
${data.postRun}
'';
in
"+${script}";
};
};
selfsignedService = {
description = "Create preliminary self-signed certificate for ${cert}";
path = [ pkgs.openssl ];
script =
''
workdir="$(mktemp -d)"
# Create CA
openssl genrsa -des3 -passout pass:xxxx -out $workdir/ca.pass.key 2048
openssl rsa -passin pass:xxxx -in $workdir/ca.pass.key -out $workdir/ca.key
openssl req -new -key $workdir/ca.key -out $workdir/ca.csr \
-subj "/C=UK/ST=Warwickshire/L=Leamington/O=OrgName/OU=Security Department/CN=example.com"
openssl x509 -req -days 1 -in $workdir/ca.csr -signkey $workdir/ca.key -out $workdir/ca.crt
# Create key
openssl genrsa -des3 -passout pass:xxxx -out $workdir/server.pass.key 2048
openssl rsa -passin pass:xxxx -in $workdir/server.pass.key -out $workdir/server.key
openssl req -new -key $workdir/server.key -out $workdir/server.csr \
-subj "/C=UK/ST=Warwickshire/L=Leamington/O=OrgName/OU=IT Department/CN=example.com"
openssl x509 -req -days 1 -in $workdir/server.csr -CA $workdir/ca.crt \
-CAkey $workdir/ca.key -CAserial $workdir/ca.srl -CAcreateserial \
-out $workdir/server.crt
# Copy key to destination
cp $workdir/server.key /var/lib/${lpath}/key.pem
# Create fullchain.pem (same format as "simp_le ... -f fullchain.pem" creates)
cat $workdir/{server.crt,ca.crt} > "/var/lib/${lpath}/fullchain.pem"
# Create full.pem for e.g. lighttpd
cat $workdir/{server.key,server.crt,ca.crt} > "/var/lib/${lpath}/full.pem"
# Give key acme permissions
chown '${data.user}:${data.group}' "/var/lib/${lpath}/"{key,fullchain,full}.pem
chmod ${rights} "/var/lib/${lpath}/"{key,fullchain,full}.pem
'';
serviceConfig = {
Type = "oneshot";
PrivateTmp = true;
StateDirectory = lpath;
User = data.user;
Group = data.group;
};
unitConfig = {
# Do not create self-signed key when key already exists
ConditionPathExists = "!/var/lib/${lpath}/key.pem";
};
};
in (
[ { name = "acme-${cert}"; value = acmeService; } ]
++ optional cfg.preliminarySelfsigned { name = "acme-selfsigned-${cert}"; value = selfsignedService; }
);
servicesAttr = listToAttrs services;
in
servicesAttr;
systemd.tmpfiles.rules =
flip mapAttrsToList cfg.certs
(cert: data: "d ${data.webroot}/.well-known/acme-challenge - ${data.user} ${data.group}");
systemd.timers = flip mapAttrs' cfg.certs (cert: data: nameValuePair
("acme-${cert}")
({
description = "Renew ACME Certificate for ${cert}";
wantedBy = [ "timers.target" ];
timerConfig = {
OnCalendar = cfg.renewInterval;
Unit = "acme-${cert}.service";
Persistent = "yes";
AccuracySec = "5m";
RandomizedDelaySec = "1h";
};
})
);
systemd.targets.acme-selfsigned-certificates = mkIf cfg.preliminarySelfsigned {};
systemd.targets.acme-certificates = {};
})
];
meta = {
maintainers = with lib.maintainers; [ abbradar fpletz globin ];
doc = ./acme.xml;
};
}