summaryrefslogtreecommitdiff
path: root/gnu/home/services/ssh.scm
blob: 34b1fe46584d496297ac9538481bb2dd01106bf1 (about) (plain)
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
460
461
462
463
;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2022 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2023 Janneke Nieuwenhuizen <janneke@gnu.org>
;;; Copyright © 2023 Nicolas Graves <ngraves@ngraves.fr>
;;; Copyright © 2023 Efraim Flashner <efraim@flashner.co.il>
;;;
;;; This file is part of GNU Guix.
;;;
;;; GNU Guix is free software; you can redistribute it and/or modify it
;;; under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 3 of the License, or (at
;;; your option) any later version.
;;;
;;; GNU Guix is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;;; GNU General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.

(define-module (gnu home services ssh)
  #:use-module (guix gexp)
  #:use-module (guix records)
  #:use-module (guix deprecation)
  #:use-module (guix diagnostics)
  #:use-module (guix i18n)
  #:use-module (gnu services)
  #:use-module (gnu services configuration)
  #:use-module (guix modules)
  #:use-module (gnu home services)
  #:use-module (gnu home services shepherd)
  #:use-module ((gnu home services utils)
                #:select (object->camel-case-string))
  #:autoload   (gnu packages base) (glibc-utf8-locales)
  #:use-module (gnu packages ssh)
  #:use-module (srfi srfi-1)
  #:use-module (srfi srfi-9)
  #:use-module (srfi srfi-9 gnu)
  #:use-module (srfi srfi-34)
  #:use-module (srfi srfi-35)
  #:use-module (ice-9 match)
  #:autoload   (ice-9 regex) (string-match match:substring)
  #:export (home-openssh-configuration
            home-openssh-configuration-authorized-keys
            home-openssh-configuration-known-hosts
            home-openssh-configuration-hosts
            home-openssh-configuration-add-keys-to-agent
            home-openssh-configuration?

            home-ssh-agent-configuration
            home-ssh-agent-openssh
            home-ssh-agent-socket-directory
            home-ssh-agent-extra-options
            home-ssh-agent-configuration?

            openssh-host
            openssh-host-host-name
            openssh-host-match-criteria
            openssh-host-identity-file
            openssh-host-name
            openssh-host-port
            openssh-host-user
            openssh-host-forward-x11?
            openssh-host-forward-x11-trusted?
            openssh-host-forward-agent?
            openssh-host-compression?
            openssh-host-proxy-command
            openssh-host-host-key-algorithms
            openssh-host-accepted-key-types
            openssh-host-extra-content
            proxy-jump
            proxy-jump-host-name
            proxy-jump-port
            proxy-jump-user
            proxy-command
            proxy-command->string

            home-openssh-service-type
            home-ssh-agent-service-type))

(define (serialize-field-name name)
  (match name
    ('accepted-key-types "PubkeyAcceptedKeyTypes")
    (_
     (let ((name (let ((str (symbol->string name)))
                   (if (string-suffix? "?" str)
                       (string->symbol (string-drop-right str 1))
                       name))))
       (object->camel-case-string name 'upper)))))

(define (serialize-string field value)
  (string-append "  " (serialize-field-name field)
                 " " value "\n"))

(define (address-family? obj)
  (memv obj (list AF_INET AF_INET6)))

(define-maybe address-family)

(define (serialize-address-family field family)
  (if (maybe-value-set? family)
      (string-append "  " (serialize-field-name field) " "
                     (cond ((= family AF_INET) "inet")
                           ((= family AF_INET6) "inet6")
                           ;; The 'else' branch is unreachable.
                           (else
                            (raise
                             (formatted-message
                              (G_ "~s: invalid address family value")
                              family))))
                     "\n")
      ""))

(define (natural-number? obj)
  (and (integer? obj) (exact? obj) (> obj 0)))

(define (serialize-natural-number field value)
  (string-append "  " (serialize-field-name field) " "
                 (number->string value) "\n"))

(define-maybe boolean)

(define (serialize-boolean field value)
  (string-append "  " (serialize-field-name field) " "
                 (if value "yes" "no") "\n"))

(define-maybe string)
(define-maybe natural-number)

(define (serialize-raw-configuration-string field value)
  (string-append value "\n"))
(define raw-configuration-string? string?)

(define (string-list? lst)
  (and (pair? lst) (every string? lst)))
(define (serialize-string-list field lst)
  (string-append "  " (serialize-field-name field) " "
                 (string-join lst ",") "\n"))

(define-maybe string-list)

(define-record-type <proxy-command>
  (proxy-command command)
  proxy-command?
  (command proxy-command->string))

(set-record-type-printer! <proxy-command>
  (lambda (obj port)
    (format port "#<proxy-command ~s>" (proxy-command->string obj))))

(define-configuration/no-serialization proxy-jump
  (user
   maybe-string
   "User name on the remote host.")
  (host-name
   (string)
   "Host name---e.g., @code{foo.example.org} or @code{192.168.1.2}.")
  (port
   maybe-natural-number
   "TCP port number to connect to."))

(define (proxy-jump->string proxy-jump)
  (match-record proxy-jump <proxy-jump>
    (host-name user port)
    (string-append
      (if (maybe-value-set? user) (string-append user "@") "")
      host-name
      (if (maybe-value-set? port) (string-append ":" (number->string port)) ""))))

(define (proxy-command-or-jump-list? x)
  (or (proxy-command? x)
      (and (list? x)
           (every proxy-jump? x))))

(define (serialize-proxy-command-or-jump-list field value)
  (if (proxy-command? value)
    (serialize-string 'proxy-command (proxy-command->string value))
    (serialize-string-list 'proxy-jump (map proxy-jump->string value))))

(define-maybe proxy-command-or-jump-list)

(define (sanitize-proxy-command properties)
  (lambda (value)
  (when (maybe-value-set? value)
    (warn-about-deprecation 'proxy-command properties #:replacement 'proxy))
  (unless (maybe-string? value)
    (configuration-field-error (source-properties->location properties) 'proxy-command value))
  value))

(define ssh-match-keywords
  '(canonical final exec host originalhost user localuser))

(define (match-criteria? str)
  ;; Rule out the case of "all" keyword.
  (if (member str '("all"
                    "canonical all"
                    "final all"))
      #t
      (let* ((first (string-take str (string-index str #\ )))
             (keyword (string->symbol (if (string-prefix? "!" first)
                                          (string-drop first 1)
                                          first))))
        (memq keyword ssh-match-keywords))))

(define (serialize-match-criteria _ value)
  (string-append "Match " value "\n"))

(define-maybe match-criteria)

(define-configuration openssh-host
  (name
   maybe-string
   "Name of this host declaration.  A @code{openssh-host} must define only
@code{name} or @code{match-criteria}.  Use host-name @code{\"*\"} for
top-level options.")
  (host-name
   maybe-string
   "Host name---e.g., @code{\"foo.example.org\"} or @code{\"192.168.1.2\"}.")
  (match-criteria
   maybe-match-criteria
   "When specified, this string denotes the set of hosts to which the entry
applies, superseding the @code{host-name} field.  Its first element must be
all or one of @code{ssh-match-keywords}.  The rest of the elements are
arguments for the keyword, or other criteria.  A @code{openssh-host} must
define only @code{name} or @code{match-criteria}.  Other host configuration
options will apply to all hosts matching @code{match-criteria}.")
  (address-family
   maybe-address-family
   "Address family to use when connecting to this host: one of
@code{AF_INET} (for IPv4 only), @code{AF_INET6} (for IPv6 only).
Additionally, the field can be left unset to allow any address family.")
  (identity-file
   maybe-string
   "The identity file to use---e.g.,
@code{\"/home/charlie/.ssh/id_ed25519\"}.")
  (port
   maybe-natural-number
   "TCP port number to connect to.")
  (user
   maybe-string
   "User name on the remote host.")
  (forward-x11?
   maybe-boolean
   "Whether to forward remote client connections to the local X11 graphical
display.")
  (forward-x11-trusted?
   maybe-boolean
   "Whether remote X11 clients have full access to the original X11 graphical
display.")
  (forward-agent?
   maybe-boolean
   "Whether the authentication agent (if any) is forwarded to the remote
machine.")
  (compression?
   maybe-boolean
   "Whether to compress data in transit.")
  (proxy-command
   maybe-string
   "The command to use to connect to the server.  As an example, a command
to connect via an HTTP proxy at 192.0.2.0 would be: @code{\"nc -X
connect -x 192.0.2.0:8080 %h %p\"}.  Using 'proxy-command' is deprecated, use
'proxy' instead."
   (sanitizer (sanitize-proxy-command (current-source-location))))
  (proxy
   maybe-proxy-command-or-jump-list
   "The command to use to connect to the server or a list of SSH hosts to jump
through before connecting to the server.")
  (host-key-algorithms
   maybe-string-list
   "The list of accepted host key algorithms---e.g.,
@code{'(\"ssh-ed25519\")}.")
  (accepted-key-types
   maybe-string-list
   "The list of accepted user public key types.")
  (extra-content
   (raw-configuration-string "")
   "Extra content appended as-is to this @code{Host} block in
@file{~/.ssh/config}."))

(define (serialize-openssh-host config)
  (define (openssh-host-name-or-match-field? field)
    (or (eq? (configuration-field-name field) 'name)
        (eq? (configuration-field-name field) 'match-criteria)))

  (string-append
   (if (maybe-value-set? (openssh-host-name config))
       (if (maybe-value-set? (openssh-host-match-criteria config))
           (raise
            (formatted-message
             (G_ "define either 'name' or 'match-criteria', not both")))
           (string-append "Host " (openssh-host-name config) "\n"))
       (if (maybe-value-set? (openssh-host-match-criteria config))
           (serialize-match-criteria #t (openssh-host-match-criteria config))
           (raise
            (formatted-message
             (G_ "define either 'name' or 'match-criteria' once")))))
   (string-concatenate
    (map (lambda (field)
           ((configuration-field-serializer field)
            (configuration-field-name field)
            ((configuration-field-getter field) config)))
         (remove openssh-host-name-or-match-field?
                 openssh-host-fields)))))

(define-record-type* <home-openssh-configuration>
  home-openssh-configuration make-home-openssh-configuration
  home-openssh-configuration?
  (authorized-keys   home-openssh-configuration-authorized-keys ;list of file-like
                     (default #f))
  (known-hosts       home-openssh-configuration-known-hosts ;unspec | list of file-like
                     (default *unspecified*))
  (hosts             home-openssh-configuration-hosts   ;list of <openssh-host>
                     (default '()))
  (add-keys-to-agent home-openssh-configuration-add-keys-to-agent ;string with limited values
                     (default "no")))

(define (serialize-add-keys-to-agent value)
  (define (valid-time-string? str)
    (and (> (string-length str) 0)
         (equal?
          str
          (match:substring
           (string-match "\
[0-9]+|([0-9]+[Ww])?([0-9]+[Dd])?([0-9]+[Hh])?([0-9]+[Mm])?([0-9]+[Ss])?"
                         str)))))

  (string-append "AddKeysToAgent "
                 (cond ((member value '("yes" "no" "confirm" "ask")) value)
                       ((valid-time-string? value) value)
                       ((and (string-prefix? "confirm" value)
                             (valid-time-string?
                              (cdr (string-split value #\ )))) value)
                       ;; The 'else' branch is unreachable.
                       (else
                        (raise
                         (formatted-message
                          (G_ "~s: invalid 'add-keys-to-agent' value")
                          value))))))

(define (openssh-configuration->string config)
  (string-join
   (cons* (serialize-add-keys-to-agent
           (home-openssh-configuration-add-keys-to-agent config))
          (map serialize-openssh-host
               (home-openssh-configuration-hosts config)))
   "\n"))

(define* (file-join name files #:optional (delimiter " "))
  "Return a file in the store called @var{name} that is the concatenation
of all the file-like objects listed in @var{files}, with @var{delimited}
inserted after each of them."
  (computed-file name
                 (with-imported-modules '((guix build utils))
                   #~(begin
                       (use-modules (guix build utils))

                       ;; Support non-ASCII file names.
                       (setenv "GUIX_LOCPATH"
                               #+(file-append glibc-utf8-locales
                                              "/lib/locale"))
                       (setlocale LC_ALL "en_US.utf8")

                       (call-with-output-file #$output
                         (lambda (output)
                           (for-each (lambda (file)
                                       (call-with-input-file file
                                         (lambda (input)
                                           (dump-port input output)))
                                       (display #$delimiter output))
                                     '#$files)))))))

(define (openssh-configuration-files config)
  (let* ((ssh-config (plain-file "ssh.conf"
                                 (openssh-configuration->string config)))
         (known-hosts (home-openssh-configuration-known-hosts config))
         (authorized-keys (home-openssh-configuration-authorized-keys config))
         (authorized-keys (and
                           authorized-keys
                           (file-join "authorized_keys" authorized-keys "\n"))))
    `(,@(if authorized-keys
            `((".ssh/authorized_keys" ,authorized-keys))
            '())
      ,@(if (unspecified? known-hosts)
            '()
            `((".ssh/known_hosts"
               ,(file-join "known_hosts" known-hosts "\n"))))
      (".ssh/config" ,ssh-config))))

(define openssh-activation
  (with-imported-modules (source-module-closure
                          '((gnu build activation)))
    #~(begin
        (use-modules (gnu build activation))

        ;; Make sure ~/.ssh is #o700.
        (let* ((home (getenv "HOME"))
               (dot-ssh (string-append home "/.ssh")))
          (mkdir-p/perms dot-ssh (getpw (getuid)) #o700)))))

(define home-openssh-service-type
  (service-type
   (name 'home-openssh)
   (extensions
    (list (service-extension home-files-service-type
                             openssh-configuration-files)
          (service-extension home-activation-service-type
                             (const openssh-activation))))
   (description "Configure the OpenSSH @acronym{SSH, secure shell} client
by providing a @file{~/.ssh/config} file, which is honored by the OpenSSH
client,@command{ssh}, and by other tools such as @command{guix deploy}.")
   (default-value (home-openssh-configuration))))


;;;
;;; Ssh-agent.
;;;
(define-record-type* <home-ssh-agent-configuration>
  home-ssh-agent-configuration make-home-ssh-agent-configuration
  home-ssh-agent-configuration?
  (openssh          home-ssh-agent-openssh          ;file-like
                    (default openssh))
  (socket-directory home-ssh-agent-socket-directory ;string
                    (default #~(string-append %user-runtime-dir "/ssh-agent")))
  (extra-options    home-ssh-agent-extra-options    ;list of string
                    (default '())))

(define (home-ssh-agent-services config)
  "Return a <shepherd-service> for an ssh-agent with CONFIG."
  (match-record config <home-ssh-agent-configuration>
    (openssh socket-directory extra-options)
    (let* ((ssh-agent (file-append openssh "/bin/ssh-agent"))
           (socket-file #~(string-append #$socket-directory "/socket"))
           (command #~`(#$ssh-agent
                        "-D" "-a" ,#$socket-file
                        #$@extra-options))
           (log-file #~(string-append %user-log-dir "/ssh-agent.log")))
      (list (shepherd-service
             (documentation "Run the ssh-agent.")
             (provision '(ssh-agent))
             (modules '((shepherd support)))    ;for '%user-runtime-dir', etc.
             (start #~(lambda _
                        (unless (file-exists? #$socket-directory)
                          (mkdir-p #$socket-directory)
                          (chmod #$socket-directory #o700))
                        (fork+exec-command #$command #:log-file #$log-file)))
             (stop #~(make-kill-destructor)))))))

(define (home-ssh-agent-environment-variables config)
  '(("SSH_AUTH_SOCK"
     . "${SSH_AUTH_SOCK-${XDG_RUNTIME_DIR-$HOME/.cache}/ssh-agent/socket}")))

(define home-ssh-agent-service-type
  (service-type
   (name 'home-ssh-agent)
   (default-value (home-ssh-agent-configuration))
   (extensions
    (list (service-extension home-shepherd-service-type
                             home-ssh-agent-services)
          (service-extension home-environment-variables-service-type
                             home-ssh-agent-environment-variables)))
   (description
    "Install and configure @command{ssh-agent} as a Shepherd service.")))