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
|
;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2010, 2011, 2013, 2014, 2016 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2013 Nikita Karetnikov <nikita@karetnikov.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 (guix gnupg)
#:use-module (ice-9 popen)
#:use-module (ice-9 match)
#:use-module (ice-9 regex)
#:use-module (ice-9 rdelim)
#:use-module (ice-9 i18n)
#:use-module (srfi srfi-1)
#:use-module (guix ui)
#:export (%gpg-command
%openpgp-key-server
gnupg-verify
gnupg-verify*
gnupg-status-good-signature?
gnupg-status-missing-key?))
;;; Commentary:
;;;
;;; GnuPG interface.
;;;
;;; Code:
(define %gpg-command
;; The GnuPG 2.x command-line program name.
(make-parameter (or (getenv "GUIX_GPG_COMMAND") "gpg")))
(define %openpgp-key-server
;; The default key server. Note that keys.gnupg.net appears to be
;; unreliable.
(make-parameter "pgp.mit.edu"))
(define (gnupg-verify sig file)
"Verify signature SIG for FILE. Return a status s-exp if GnuPG failed."
(define (status-line->sexp line)
;; See file `doc/DETAILS' in GnuPG.
(define sigid-rx
(make-regexp
"^\\[GNUPG:\\] SIG_ID ([A-Za-z0-9+/]+) ([[:digit:]]{4}-[[:digit:]]{2}-[[:digit:]]{2}) ([[:digit:]]+)"))
(define goodsig-rx
(make-regexp "^\\[GNUPG:\\] GOODSIG ([[:xdigit:]]+) (.+)$"))
(define validsig-rx
(make-regexp
"^\\[GNUPG:\\] VALIDSIG ([[:xdigit:]]+) ([[:digit:]]{4}-[[:digit:]]{2}-[[:digit:]]{2}) ([[:digit:]]+) .*$"))
(define expkeysig-rx ; good signature, but expired key
(make-regexp "^\\[GNUPG:\\] EXPKEYSIG ([[:xdigit:]]+) (.*)$"))
(define errsig-rx
(make-regexp
"^\\[GNUPG:\\] ERRSIG ([[:xdigit:]]+) ([^ ]+) ([^ ]+) ([^ ]+) ([[:digit:]]+) ([[:digit:]]+)"))
(cond ((regexp-exec sigid-rx line)
=>
(lambda (match)
`(signature-id ,(match:substring match 1) ; sig id
,(match:substring match 2) ; date
,(string->number ; timestamp
(match:substring match 3)))))
((regexp-exec goodsig-rx line)
=>
(lambda (match)
`(good-signature ,(match:substring match 1) ; key id
,(match:substring match 2)))) ; user name
((regexp-exec validsig-rx line)
=>
(lambda (match)
`(valid-signature ,(match:substring match 1) ; fingerprint
,(match:substring match 2) ; sig creation date
,(string->number ; timestamp
(match:substring match 3)))))
((regexp-exec expkeysig-rx line)
=>
(lambda (match)
`(expired-key-signature ,(match:substring match 1) ; fingerprint
,(match:substring match 2)))) ; user name
((regexp-exec errsig-rx line)
=>
(lambda (match)
`(signature-error ,(match:substring match 1) ; key id or fingerprint
,(match:substring match 2) ; pubkey algo
,(match:substring match 3) ; hash algo
,(match:substring match 4) ; sig class
,(string->number ; timestamp
(match:substring match 5))
,(let ((rc
(string->number ; return code
(match:substring match 6))))
(case rc
((9) 'missing-key)
((4) 'unknown-algorithm)
(else rc))))))
(else
`(unparsed-line ,line))))
(define (parse-status input)
(let loop ((line (read-line input))
(result '()))
(if (eof-object? line)
(reverse result)
(loop (read-line input)
(cons (status-line->sexp line) result)))))
(let* ((pipe (open-pipe* OPEN_READ (%gpg-command) "--status-fd=1"
"--verify" sig file))
(status (parse-status pipe)))
;; Ignore PIPE's exit status since STATUS above should contain all the
;; info we need.
(close-pipe pipe)
status))
(define (gnupg-status-good-signature? status)
"If STATUS, as returned by `gnupg-verify', denotes a good signature, return
a key-id/user pair; return #f otherwise."
(any (lambda (sexp)
(match sexp
(((or 'good-signature 'expired-key-signature) key-id user)
(cons key-id user))
(_ #f)))
status))
(define (gnupg-status-missing-key? status)
"If STATUS denotes a missing-key error, then return the key-id of the
missing key."
(any (lambda (sexp)
(match sexp
(('signature-error key-id _ ...)
key-id)
(_ #f)))
status))
(define (gnupg-receive-keys key-id server)
(system* (%gpg-command) "--keyserver" server "--recv-keys" key-id))
(define* (gnupg-verify* sig file
#:key (key-download 'interactive)
(server (%openpgp-key-server)))
"Like `gnupg-verify', but try downloading the public key if it's missing.
Return #t if the signature was good, #f otherwise. KEY-DOWNLOAD specifies a
download policy for missing OpenPGP keys; allowed values: 'always', 'never',
and 'interactive' (default)."
(let ((status (gnupg-verify sig file)))
(or (gnupg-status-good-signature? status)
(let ((missing (gnupg-status-missing-key? status)))
(define (download-and-try-again)
;; Download the missing key and try again.
(begin
(gnupg-receive-keys missing server)
(gnupg-status-good-signature? (gnupg-verify sig file))))
(define (receive?)
(let ((answer
(begin (format #t (G_ "~a~a~%")
"Would you like to download this key "
"and add it to your keyring?")
(read-line))))
(string-match (locale-yes-regexp) answer)))
(and missing
(case key-download
((never) #f)
((always)
(download-and-try-again))
(else
(and (receive?)
(download-and-try-again)))))))))
;;; gnupg.scm ends here
|
