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
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
|
{ config, lib, pkgs, ... }:
with lib;
let
cfg = config.security.acme;
certOpts = { name, ... }: {
options = {
webroot = mkOption {
type = types.nullOr types.str;
default = null;
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).
'';
};
server = mkOption {
type = types.nullOr types.str;
default = null;
description = ''
ACME Directory Resource URI. Defaults to let's encrypt
production endpoint,
https://acme-v02.api.letsencrypt.org/directory, if unset.
'';
};
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 = cfg.email;
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.<name>.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.
'';
};
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.
'';
};
keyType = mkOption {
type = types.str;
default = "ec384";
description = ''
Key type to use for private keys.
For an up to date list of supported values check the --key-type option
at https://go-acme.github.io/lego/usage/cli/#usage.
'';
};
dnsProvider = mkOption {
type = types.nullOr types.str;
default = null;
example = "route53";
description = ''
DNS Challenge provider. For a list of supported providers, see the "code"
field of the DNS providers listed at https://go-acme.github.io/lego/dns/.
'';
};
credentialsFile = mkOption {
type = types.path;
description = ''
Path to an EnvironmentFile for the cert's service containing any required and
optional environment variables for your selected dnsProvider.
To find out what values you need to set, consult the documentation at
https://go-acme.github.io/lego/dns/ for the corresponding dnsProvider.
'';
example = "/var/src/secrets/example.org-route53-api-token";
};
dnsPropagationCheck = mkOption {
type = types.bool;
default = true;
description = ''
Toggles lego DNS propagation check, which is used alongside DNS-01
challenge to ensure the DNS entries required are available.
'';
};
ocspMustStaple = mkOption {
type = types.bool;
default = false;
description = ''
Turns on the OCSP Must-Staple TLS extension.
Make sure you know what you're doing! See:
<itemizedlist>
<listitem><para><link xlink:href="https://blog.apnic.net/2019/01/15/is-the-web-ready-for-ocsp-must-staple/" /></para></listitem>
<listitem><para><link xlink:href="https://blog.hboeck.de/archives/886-The-Problem-with-OCSP-Stapling-and-Must-Staple-and-why-Certificate-Revocation-is-still-broken.html" /></para></listitem>
</itemizedlist>
'';
};
extraLegoRenewFlags = mkOption {
type = types.listOf types.str;
default = [];
description = ''
Additional flags to pass to lego renew.
'';
};
};
};
in
{
###### interface
imports = [
(mkRemovedOptionModule [ "security" "acme" "production" ] ''
Use security.acme.server to define your staging ACME server URL instead.
To use the let's encrypt staging server, use security.acme.server =
"https://acme-staging-v02.api.letsencrypt.org/directory".
''
)
(mkRemovedOptionModule [ "security" "acme" "directory"] "ACME Directory is now hardcoded to /var/lib/acme and its permisisons are managed by systemd. See https://github.com/NixOS/nixpkgs/issues/53852 for more info.")
(mkRemovedOptionModule [ "security" "acme" "preDelay"] "This option has been removed. If you want to make sure that something executes before certificates are provisioned, add a RequiredBy=acme-\${cert}.service to the service you want to execute before the cert renewal")
(mkRemovedOptionModule [ "security" "acme" "activationDelay"] "This option has been removed. If you want to make sure that something executes before certificates are provisioned, add a RequiredBy=acme-\${cert}.service to the service you want to execute before the cert renewal")
(mkChangedOptionModule [ "security" "acme" "validMin"] [ "security" "acme" "validMinDays"] (config: config.security.acme.validMin / (24 * 3600)))
];
options = {
security.acme = {
validMinDays = mkOption {
type = types.int;
default = 30;
description = "Minimum remaining validity before renewal in days.";
};
email = mkOption {
type = types.nullOr types.str;
default = null;
description = "Contact email address for the CA to be able to reach you.";
};
renewInterval = mkOption {
type = types.str;
default = "daily";
description = ''
Systemd calendar expression when to check for renewal. See
<citerefentry><refentrytitle>systemd.time</refentrytitle>
<manvolnum>7</manvolnum></citerefentry>.
'';
};
server = mkOption {
type = types.nullOr types.str;
default = null;
description = ''
ACME Directory Resource URI. Defaults to let's encrypt
production endpoint,
<literal>https://acme-v02.api.letsencrypt.org/directory</literal>, if unset.
'';
};
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.
'';
};
acceptTerms = mkOption {
type = types.bool;
default = false;
description = ''
Accept the CA's terms of service. The default provier is Let's Encrypt,
you can find their ToS at https://letsencrypt.org/repository/
'';
};
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 != { }) {
assertions = let
certs = (mapAttrsToList (k: v: v) cfg.certs);
in [
{
assertion = all (certOpts: certOpts.dnsProvider == null || certOpts.webroot == null) certs;
message = ''
Options `security.acme.certs.<name>.dnsProvider` and
`security.acme.certs.<name>.webroot` are mutually exclusive.
'';
}
{
assertion = cfg.email != null || all (certOpts: certOpts.email != null) certs;
message = ''
You must define `security.acme.certs.<name>.email` or
`security.acme.email` to register with the CA.
'';
}
{
assertion = cfg.acceptTerms;
message = ''
You must accept the CA's terms of service before using
the ACME module by setting `security.acme.acceptTerms`
to `true`. For Let's Encrypt's ToS see https://letsencrypt.org/repository/
'';
}
];
systemd.services = let
services = concatLists servicesLists;
servicesLists = mapAttrsToList certToServices cfg.certs;
certToServices = cert: data:
let
# StateDirectory must be relative, and will be created under /var/lib by systemd
lpath = "acme/${cert}";
apath = "/var/lib/${lpath}";
spath = "/var/lib/acme/.lego/${cert}";
fileMode = if data.allowKeysForGroup then "640" else "600";
globalOpts = [ "-d" data.domain "--email" data.email "--path" "." "--key-type" data.keyType ]
++ optionals (cfg.acceptTerms) [ "--accept-tos" ]
++ optionals (data.dnsProvider != null && !data.dnsPropagationCheck) [ "--dns.disable-cp" ]
++ concatLists (mapAttrsToList (name: root: [ "-d" name ]) data.extraDomains)
++ (if data.dnsProvider != null then [ "--dns" data.dnsProvider ] else [ "--http" "--http.webroot" data.webroot ])
++ optionals (cfg.server != null || data.server != null) ["--server" (if data.server == null then cfg.server else data.server)];
certOpts = optionals data.ocspMustStaple [ "--must-staple" ];
runOpts = escapeShellArgs (globalOpts ++ [ "run" ] ++ certOpts);
renewOpts = escapeShellArgs (globalOpts ++
[ "renew" "--days" (toString cfg.validMinDays) ] ++
certOpts ++ data.extraLegoRenewFlags);
acmeService = {
description = "Renew ACME Certificate for ${cert}";
after = [ "network.target" "network-online.target" ];
wants = [ "network-online.target" ];
wantedBy = mkIf (!config.boot.isContainer) [ "multi-user.target" ];
serviceConfig = {
Type = "oneshot";
User = data.user;
Group = data.group;
PrivateTmp = true;
StateDirectory = "acme/.lego/${cert} acme/.lego/accounts ${lpath}";
StateDirectoryMode = if data.allowKeysForGroup then "750" else "700";
WorkingDirectory = spath;
# Only try loading the credentialsFile if the dns challenge is enabled
EnvironmentFile = if data.dnsProvider != null then data.credentialsFile else null;
ExecStart = pkgs.writeScript "acme-start" ''
#!${pkgs.runtimeShell} -e
test -L ${spath}/accounts -o -d ${spath}/accounts || ln -s ../accounts ${spath}/accounts
${pkgs.lego}/bin/lego ${renewOpts} || ${pkgs.lego}/bin/lego ${runOpts}
'';
ExecStartPost =
let
keyName = builtins.replaceStrings ["*"] ["_"] data.domain;
script = pkgs.writeScript "acme-post-start" ''
#!${pkgs.runtimeShell} -e
cd ${apath}
# Test that existing cert is older than new cert
KEY=${spath}/certificates/${keyName}.key
if [ -e $KEY -a $KEY -nt key.pem ]; then
cp -p ${spath}/certificates/${keyName}.key key.pem
cp -p ${spath}/certificates/${keyName}.crt fullchain.pem
cp -p ${spath}/certificates/${keyName}.issuer.crt chain.pem
ln -sf fullchain.pem cert.pem
cat key.pem fullchain.pem > full.pem
fi
chmod ${fileMode} *.pem
chown '${data.user}:${data.group}' *.pem
${data.postRun}
'';
in
"+${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 ${apath}/key.pem
# Create fullchain.pem (same format as "simp_le ... -f fullchain.pem" creates)
cat $workdir/{server.crt,ca.crt} > "${apath}/fullchain.pem"
# Create full.pem for e.g. lighttpd
cat $workdir/{server.key,server.crt,ca.crt} > "${apath}/full.pem"
# Give key acme permissions
chown '${data.user}:${data.group}' "${apath}/"{key,fullchain,full}.pem
chmod ${fileMode} "${apath}/"{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 = "!${apath}/key.pem";
};
};
in (
[ { name = "acme-${cert}"; value = acmeService; } ]
++ optional cfg.preliminarySelfsigned { name = "acme-selfsigned-${cert}"; value = selfsignedService; }
);
servicesAttr = listToAttrs services;
in
servicesAttr;
systemd.tmpfiles.rules =
map (data: "d ${data.webroot}/.well-known/acme-challenge - ${data.user} ${data.group}") (filter (data: data.webroot != null) (attrValues cfg.certs));
systemd.timers = let
# Allow systemd to pick a convenient time within the day
# to run the check.
# This allows the coalescing of multiple timer jobs.
# We divide by the number of certificates so that if you
# have many certificates, the renewals are distributed over
# the course of the day to avoid rate limits.
numCerts = length (attrNames cfg.certs);
_24hSecs = 60 * 60 * 24;
AccuracySec = "${toString (_24hSecs / numCerts)}s";
in 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";
inherit AccuracySec;
# Skew randomly within the day, per https://letsencrypt.org/docs/integration-guide/.
RandomizedDelaySec = "24h";
};
})
);
systemd.targets.acme-selfsigned-certificates = mkIf cfg.preliminarySelfsigned {};
systemd.targets.acme-certificates = {};
})
];
meta = {
maintainers = with lib.maintainers; [ abbradar fpletz globin m1cr0man ];
doc = ./acme.xml;
};
}
|