summary refs log tree commit diff
path: root/gnu/build/secret-service.scm
blob: 6697e6e1b01bdb4b1a1a099890f278307cfb257e (plain) (blame)
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
;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2020 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2020 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
;;;
;;; 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 build secret-service)
  #:use-module (guix build utils)

  #:use-module (srfi srfi-26)
  #:use-module (rnrs bytevectors)
  #:use-module (ice-9 binary-ports)
  #:use-module (ice-9 match)
  #:use-module (ice-9 rdelim)

  #:export (secret-service-receive-secrets
            secret-service-send-secrets))

;;; Commentary:
;;;
;;; Utility procedures for copying secrets into a VM.
;;;
;;; Code:

(define* (secret-service-send-secrets port secret-root #:key (retry 60))
  "Copy all files under SECRET-ROOT using TCP to secret-service listening at
local PORT.  If connect fails, sleep 1s and retry RETRY times."

  (define (file->file+size+mode file-name)
    (let ((stat (stat file-name))
          (target (substring file-name (string-length secret-root))))
      (list target (stat:size stat) (stat:mode stat))))

  (format (current-error-port) "sending secrets to ~a~%" port)
  (let ((sock (socket AF_INET SOCK_STREAM 0))
        (addr (make-socket-address AF_INET INADDR_LOOPBACK port)))
    ;; connect to wait for port
    (let loop ((retry retry))
      (catch 'system-error
        (cute connect sock addr)
        (lambda (key . args)
          (when (zero? retry)
            (apply throw key args))
          (format (current-error-port)
                  "secret service: retrying connection [~a attempts left]~%"
                  (- retry 1))
          (sleep 1)
          (loop (1- retry)))))

    (format (current-error-port)
            "secret service: connected; sending files in ~s~%"
            secret-root)
    (let* ((files (if secret-root (find-files secret-root) '()))
           (files-sizes-modes (map file->file+size+mode files))
           (secrets `(secrets
                      (version 0)
                      (files ,files-sizes-modes))))
      (write secrets sock)
      (for-each (lambda (file)
                  (call-with-input-file file
                    (lambda (input)
                      (dump-port input sock))))
                files))))

(define (secret-service-receive-secrets port)
  "Listen to local PORT and wait for a secret service client to send secrets.
Write them to the file system.  Return the list of files installed on success,
and #f otherwise."

  (define (wait-for-client port)
    ;; Wait for a TCP connection on PORT.  Note: We cannot use the
    ;; virtio-serial ports, which would be safer, because they are
    ;; (presumably) unsupported on GNU/Hurd.
    (let ((sock (socket AF_INET SOCK_STREAM 0)))
      (bind sock AF_INET INADDR_ANY port)
      (listen sock 1)
      (format (current-error-port)
              "secret service: waiting for secrets on port ~a...~%"
              port)
      (match (select (list sock) '() '() 60)
        (((_) () ())
         (match (accept sock)
           ((client . address)
            (format (current-error-port)
                    "secret service: client connection from ~a~%"
                    (inet-ntop (sockaddr:fam address)
                               (sockaddr:addr address)))
            (close-port sock)
            client)))
        ((() () ())
         (format (current-error-port)
                 "secret service: did not receive any secrets; time out~%")
         #f))))

  ;; TODO: Remove when (@ (guix build utils) dump-port) has a 'size'
  ;; parameter.
  (define (dump in out size)
    ;; Copy SIZE bytes from IN to OUT.
    (define buf-size 65536)
    (define buf (make-bytevector buf-size))

    (let loop ((left size))
      (if (<= left 0)
          0
          (let ((read (get-bytevector-n! in buf 0 (min left buf-size))))
            (if (eof-object? read)
                left
                (begin
                  (put-bytevector out buf 0 read)
                  (loop (- left read))))))))

  (define (read-secrets port)
    ;; Read secret files from PORT and install them.
    (match (false-if-exception (read port))
      (('secrets ('version 0)
                 ('files ((files sizes modes) ...)))
       (for-each (lambda (file size mode)
                   (format (current-error-port)
                           "secret service: \
installing file '~a' (~a bytes)...~%"
                           file size)
                   (mkdir-p (dirname file))
                   (call-with-output-file file
                     (lambda (output)
                       (dump port output size)
                       (chmod file mode))))
                 files sizes modes)
       files)
      (_
       (format (current-error-port)
               "secret service: invalid secrets received~%")
       #f)))

  (let* ((port   (wait-for-client port))
         (result (and=> port read-secrets)))
    (when port
      (close-port port))
    result))

;;; secret-service.scm ends here