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
|
;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2014, 2015 Ludovic Courtès <ludo@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 services ssh)
#:use-module (guix gexp)
#:use-module (guix store)
#:use-module (gnu services)
#:use-module (gnu system linux) ; 'pam-service'
#:use-module (gnu packages lsh)
#:export (lsh-service))
;;; Commentary:
;;;
;;; This module implements secure shell (SSH) services.
;;;
;;; Code:
(define %yarrow-seed
"/var/spool/lsh/yarrow-seed-file")
(define (activation lsh host-key)
"Return the gexp to activate the LSH service for HOST-KEY."
#~(begin
(unless (file-exists? #$%yarrow-seed)
(system* (string-append #$lsh "/bin/lsh-make-seed")
"--sloppy" "-o" #$%yarrow-seed))
(unless (file-exists? #$host-key)
(mkdir-p (dirname #$host-key))
(format #t "creating SSH host key '~a'...~%" #$host-key)
;; FIXME: We're just doing a simple pipeline, but 'system' cannot be
;; used yet because /bin/sh might be dangling; factorize this somehow.
(let* ((in+out (pipe))
(keygen (primitive-fork)))
(case keygen
((0)
(close-port (car in+out))
(close-fdes 1)
(dup2 (fileno (cdr in+out)) 1)
(execl (string-append #$lsh "/bin/lsh-keygen")
"lsh-keygen" "--server"))
(else
(let ((write-key (primitive-fork)))
(case write-key
((0)
(close-port (cdr in+out))
(close-fdes 0)
(dup2 (fileno (car in+out)) 0)
(execl (string-append #$lsh "/bin/lsh-writekey")
"lsh-writekey" "--server" "-o" #$host-key))
(else
(close-port (car in+out))
(close-port (cdr in+out))
(waitpid keygen)
(waitpid write-key))))))))))
(define* (lsh-service #:key
(lsh lsh)
(daemonic? #t)
(host-key "/etc/lsh/host-key")
(interfaces '())
(port-number 22)
(allow-empty-passwords? #f)
(root-login? #f)
(syslog-output? #t)
(pid-file? #f)
(pid-file "/var/run/lshd.pid")
(x11-forwarding? #t)
(tcp/ip-forwarding? #t)
(password-authentication? #t)
(public-key-authentication? #t)
(initialize? #t))
"Run the @command{lshd} program from @var{lsh} to listen on port @var{port-number}.
@var{host-key} must designate a file containing the host key, and readable
only by root.
When @var{daemonic?} is true, @command{lshd} will detach from the
controlling terminal and log its output to syslogd, unless one sets
@var{syslog-output?} to false. Obviously, it also makes lsh-service
depend on existence of syslogd service. When @var{pid-file?} is true,
@command{lshd} writes its PID to the file called @var{pid-file}.
When @var{initialize?} is true, automatically create the seed and host key
upon service activation if they do not exist yet. This may take long and
require interaction.
When @var{initialize?} is false, it is up to the user to initialize the
randomness generator (@pxref{lsh-make-seed,,, lsh, LSH Manual}), and to create
a key pair with the private key stored in file @var{host-key} (@pxref{lshd
basics,,, lsh, LSH Manual}).
When @var{interfaces} is empty, lshd listens for connections on all the
network interfaces; otherwise, @var{interfaces} must be a list of host names
or addresses.
@var{allow-empty-passwords?} specifies whether to accept log-ins with empty
passwords, and @var{root-login?} specifies whether to accept log-ins as
root.
The other options should be self-descriptive."
(define lsh-command
(append
(cons #~(string-append #$lsh "/sbin/lshd")
(if daemonic?
(let ((syslog (if syslog-output? '()
(list "--no-syslog"))))
(cons "--daemonic"
(if pid-file?
(cons #~(string-append "--pid-file=" #$pid-file)
syslog)
(cons "--no-pid-file" syslog))))
(if pid-file?
(list #~(string-append "--pid-file=" #$pid-file))
'())))
(cons* #~(string-append "--host-key=" #$host-key)
#~(string-append "--password-helper=" #$lsh "/sbin/lsh-pam-checkpw")
#~(string-append "--subsystems=sftp=" #$lsh "/sbin/sftp-server")
"-p" (number->string port-number)
(if password-authentication? "--password" "--no-password")
(if public-key-authentication?
"--publickey" "--no-publickey")
(if root-login?
"--root-login" "--no-root-login")
(if x11-forwarding?
"--x11-forward" "--no-x11-forward")
(if tcp/ip-forwarding?
"--tcpip-forward" "--no-tcpip-forward")
(if (null? interfaces)
'()
(list (string-append "--interfaces="
(string-join interfaces ",")))))))
(define requires
(if (and daemonic? syslog-output?)
'(networking syslogd)
'(networking)))
(service
(documentation "GNU lsh SSH server")
(provision '(ssh-daemon))
(requirement requires)
(start #~(make-forkexec-constructor (list #$@lsh-command)))
(stop #~(make-kill-destructor))
(pam-services
(list (unix-pam-service
"lshd"
#:allow-empty-passwords? allow-empty-passwords?)))
(activate #~(begin
(use-modules (guix build utils))
(mkdir-p "/var/spool/lsh")
#$(if initialize?
(activation lsh host-key)
#t)))))
;;; ssh.scm ends here
|
