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
|
#!/usr/bin/perl -T
#----------------------------------------------------------------------
# ACME client written with process isolation and minimal privileges in mind
# (account key manager)
# Copyright © 2015-2021 Guilhem Moulin <guilhem@fripost.org>
#
# This program 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.
#
# This program 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 this program. If not, see <https://www.gnu.org/licenses/>.
#----------------------------------------------------------------------
use v5.14.2;
use strict;
use warnings;
our $VERSION = '0.3';
my $PROTOCOL_VERSION = 1;
my $NAME = 'lacme-accountd';
use Errno 'EINTR';
use Getopt::Long qw/:config posix_default no_ignore_case gnu_getopt auto_version/;
use List::Util 'first';
use MIME::Base64 'encode_base64url';
use Socket qw/PF_UNIX SOCK_STREAM SHUT_RDWR/;
use Config::Tiny ();
use JSON ();
# Clean up PATH
$ENV{PATH} = join ':', qw{/usr/bin /bin};
delete @ENV{qw/IFS CDPATH ENV BASH_ENV/};
my ($SOCKNAME, $S, %OPTS);
$SIG{$_} = sub() { exit } foreach qw/INT TERM/; # run the END block upon SIGINT/SIGTERM
#############################################################################
# Parse and validate configuration
#
sub usage(;$$) {
my $rv = shift // 0;
if ($rv) {
my $msg = shift;
print STDERR $msg."\n" if defined $msg;
print STDERR "Try '$NAME --help' or consult the manpage for more information.\n";
}
else {
print STDERR "Usage: $NAME [--config=FILE] [--privkey=ARG] [--socket=PATH] [--quiet]\n"
."Consult the manpage for more information.\n";
}
exit $rv;
}
usage(1) unless GetOptions(\%OPTS, qw/config=s privkey=s socket=s conn-fd=i quiet|q debug help|h/);
usage(0) if $OPTS{help};
do {
my $conffile = $OPTS{config} // first { -f $_ }
( ($ENV{XDG_CONFIG_HOME} // "$ENV{HOME}/.config") . "/lacme/$NAME.conf"
, "@@sysconfdir@@/lacme/$NAME.conf"
);
die "Error: Can't find configuration file\n" unless defined $conffile;
print STDERR "Using configuration file: $conffile\n" if $OPTS{debug};
my $h = Config::Tiny::->read($conffile) or die Config::Tiny::->errstr()."\n";
my $h2 = delete $h->{_} // {};
die "Invalid section(s): ".join(', ', keys %$h)."\n" if %$h;
my %h = map { $_ => delete $h2->{$_} } qw/privkey gpg socket quiet/;
die "Unknown option(s): ".join(', ', keys %$h2)."\n" if %$h2;
$h{quiet} = lc $h{quiet} eq 'yes' ? 1 : 0 if defined $h{quiet};
$OPTS{$_} //= $h{$_} foreach grep {defined $h{$_}} keys %h;
$OPTS{quiet} = 0 if $OPTS{debug};
die "Error: 'privkey' is not specified\n" unless defined $OPTS{privkey};
};
#############################################################################
# Build the JSON Web Key (RFC 7517) from the account key's public parameters,
# and determine the signing method $SIGN.
#
my ($JWK, $SIGN);
if ($OPTS{privkey} =~ /\A(file|gpg):(\p{Print}+)\z/) {
my ($method, $filename) = ($1,$2);
my ($fh, @command);
if ($method eq 'file') {
# generate with `openssl genpkey -algorithm RSA`
open $fh, '<', $filename or die "Error: Can't open $filename: $!\n";
}
elsif ($method eq 'gpg') {
@command = split /\s+/, ($OPTS{gpg} // 'gpg --quiet');
open $fh, '-|', @command, qw/-o - --decrypt --/, $filename or die "fork: $!";
}
else {
die; # impossible
}
my $str = do {local $/ = undef; <$fh>};
close $fh or die $! ?
"Can't close: $!" :
"Error: $command[0] exited with value ".($? >> 8)."\n";
require 'Crypt/OpenSSL/RSA.pm';
my $rsa = Crypt::OpenSSL::RSA->new_private_key($str);
undef $str;
die "Error: $filename: Not a private key\n" unless $rsa->is_private();
die "Error: $filename: Invalid key\n" unless $rsa->check_key();
$rsa->use_sha256_hash();
require 'Crypt/OpenSSL/Bignum.pm';
my ($n, $e) = $rsa->get_key_parameters(); # don't include private params!
$_ = encode_base64url($_->to_bin()) foreach ($n, $e);
$JWK = { kty => 'RSA', n => $n, e => $e };
$SIGN = sub($) { $rsa->sign($_[0]) };
}
else {
die "Error: unsupported method: $OPTS{privkey}\n";
}
my $JWK_STR = JSON::->new->encode($JWK);
#############################################################################
# Create the server UNIX socket and bind(2) against it.
# NOTE: We don't use the abstract namespace so we can rely on the file
# permissions to keep other users out. (Also, OpenSSH 7.1 doesn't seem
# to support the abstract namespace.) The downside is that we have to
# delete the file manually.
#
if (defined $OPTS{'conn-fd'}) {
die "Invalid file descriptor" unless $OPTS{'conn-fd'} =~ /\A(\d+)\z/;
# untaint and fdopen(3) our end of the socket pair
open ($S, '+<&=', $1+0) or die "fdopen $1: $!";
} else {
my $sockname = $OPTS{socket} // (defined $ENV{XDG_RUNTIME_DIR} ? "$ENV{XDG_RUNTIME_DIR}/S.lacme" : undef);
die "Missing socket option\n" unless defined $sockname;
$sockname = $sockname =~ /\A(\p{Print}+)\z/ ? $1 : die "Invalid socket name\n"; # untaint $sockname
# ensure we're the only user with write access to the parent dir
my $dirname = $sockname =~ s/[^\/]+$//r;
my @stat = stat($dirname) or die "Can't stat $dirname: $!";
die "Error: insecure permissions on $dirname\n" if ($stat[2] & 0022) != 0;
my $umask = umask(0177) // die "umask: $!";
print STDERR "Starting lacme Account Key Manager at $sockname\n" unless $OPTS{quiet};
socket(my $sock, PF_UNIX, SOCK_STREAM, 0) or die "socket: $!";
my $sockaddr = Socket::sockaddr_un($sockname) // die;
bind($sock, $sockaddr) or die "bind: $!";
($SOCKNAME, $S) = ($sockname, $sock);
listen($S, 1) or die "listen: $!";
umask($umask) // die "umask: $!";
};
#############################################################################
# For each new connection, send the protocol version and the account key's
# public parameters, then sign whatever comes in
#
sub conn($;$) {
my $conn = shift;
my $count = shift;
$conn->printflush( "$PROTOCOL_VERSION OK", "\r\n", $JWK_STR, "\r\n" );
# sign whatever comes in
while (defined (my $data = $conn->getline())) {
$data =~ s/\r\n\z// or die;
print STDERR "[$count] >>> Issuing SHA-256 signature for: $data\n" unless $OPTS{quiet};
my $sig = $SIGN->($data);
$conn->printflush( encode_base64url($sig), "\r\n" );
}
}
if (defined $OPTS{'conn-fd'}) {
conn($S, $$);
} else {
$SIG{PIPE} = 'IGNORE'; # ignore broken pipes
for (my $count = 0;; $count++) {
accept(my $conn, $S) or do {
next if $! == EINTR; # try again if accept(2) was interrupted by a signal
die "accept: $!";
};
print STDERR "[$count] >>> Accepted new connection\n" unless $OPTS{quiet};
conn($conn, $count);
print STDERR "[$count] >>> Connection terminated\n" unless $OPTS{quiet};
close $conn or warn "Can't close: $!";
}
}
#############################################################################
#
END {
if (defined $SOCKNAME and -S $SOCKNAME) {
print STDERR "Unlinking $SOCKNAME\n" if $OPTS{debug};
unlink $SOCKNAME or print STDERR "Can't unlink $SOCKNAME: $!\n";
}
if (defined $S) {
print STDERR "Shutting down and closing lacme Account Key Manager\n" unless $OPTS{quiet};
shutdown($S, SHUT_RDWR) or warn "shutdown: $!";
close $S or print STDERR "Can't close: $!\n";
}
}
|
