File: client

package info (click to toggle)
lacme 0.8.0-1
  • links: PTS, VCS
  • area: main
  • in suites: bullseye
  • size: 568 kB
  • sloc: perl: 1,242; sh: 225; makefile: 95
file content (429 lines) | stat: -rwxr-xr-x 16,129 bytes parent folder | download | duplicates (2)
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
#!/usr/bin/perl -T

#----------------------------------------------------------------------
# ACME client written with process isolation and minimal privileges in mind
# 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;

# Usage: client COMMAND CONFIG_FD SOCKET_FD [ARGUMENTS]
#
# fdopen(3) the file descriptor SOCKET_FD (corresponding to the
# listening lacme-accountd socket), connect(2) to it to retrieve the
# account key's public parameters and later send data to be signed by
# the master component (using the account key).
#
# CONFIG_FD is a read-only file descriptor associated with the
# configuration file at pos 0.  (This is needed since this process
# doesn't know its name and might not have read access to it.)
#
# NOTE: one needs to chdir(2) to an appropriate ACME challenge directory
# before running this program, since challenge tokens are (on purpose)
# only written to the current directory.  If COMMAND is challenge-less,
# one should chdir(2) to the root directory "/" instead.
#
# NOTE: one should run this program as an unprivileged user:group such
# as "nobody:nogroup"; bind(2)'ing to a restricted UNIX socket (for
# instance own by another user and created with umask 0177) is not a
# problem since SOCKET_FD can be bound as root prior to the execve(2).

our $VERSION = '0.8.0';
my $PROTOCOL_VERSION = 1;
my $NAME = 'lacme-client';

use Errno 'EEXIST';
use Fcntl qw/O_CREAT O_EXCL O_WRONLY/;
use Digest::SHA 'sha256';
use MIME::Base64 qw/encode_base64 encode_base64url/;

use Date::Parse ();
use LWP::UserAgent ();
use JSON ();

use Config::Tiny ();

# Clean up PATH
$ENV{PATH} = join ':', qw{/usr/bin /bin};
delete @ENV{qw/IFS CDPATH ENV BASH_ENV/};

my $COMMAND = shift @ARGV // die;

# Untaint and fdopen(3) the configuration file and listening socket
(shift @ARGV // die) =~ /\A(\d+)\z/ or die;
open (my $CONFFILE, '<&=', $1+0) or die "fdopen $1: $!";
(shift @ARGV // die) =~ /\A(\d+)\z/ or die;
open (my $S, '+<&=', $1+0) or die "fdopen $1: $!";

# JSON keys need to be sorted lexicographically (for instance in the thumbprint)
sub json() { JSON::->new->utf8->canonical(); }


#############################################################################
# Read the protocol version and JSON Web Key (RFC 7517) from the
# lacme-accountd socket
#

my ($JWK, $JWK_thumbprint, $ALG, $KID);
do {
    my $greeting = $S->getline();
    die "Error: Invalid client version\n" unless defined $greeting and
        $greeting =~ /\A(\d+) OK(?: (.*))?\r\n\z/ and $1 == $PROTOCOL_VERSION;
    if (defined (my $extra = $2)) {
        my $h = eval { JSON::->new->decode($extra) };
        if ($@ or !defined $h) {
            print STDERR "WARN: Ignoring extra greeting data from accountd \"$extra\"\n";
        } else {
            print STDERR "Received extra greeting data from accountd: $extra\n" if $ENV{DEBUG};
            ($JWK_thumbprint, $ALG, $KID) = @$h{qw/jwk-thumbprint alg kid/};
        }
    }
    my $jwk_str = $S->getline() // die "ERROR: No JWK from lacme-accountd\n";
    $JWK = JSON::->new->decode($jwk_str);
    $JWK_thumbprint //= encode_base64url(sha256(json()->encode($JWK))); # SHA-256 is hardcoded, see RFC 8555 sec. 8.1
    $ALG //= "RS256";
};


#############################################################################
# Parse configuration (already validated by the master) and create the
# LWP::UserAgent object
#

my $CONFIG = do {
    my $conf = do { local $/ = undef; <$CONFFILE> };
    close $CONFFILE or die "close: $!";
    my $h = Config::Tiny::->read_string($conf) or die Config::Tiny::->errstr()."\n";
    $h->{_} //= {};
    $h->{client}->{$_} //= $h->{_}->{$_} foreach keys %{$h->{_}}; # add defaults
    $h->{client};
};
my $UA = do {
    my %args = %$CONFIG;
    my $verify = lc (delete $args{SSL_verify} // 'Yes') eq 'no' ? 0 : 1;
    my %ssl_opts = ( verify_hostname => $verify );
    $ssl_opts{$_} = $args{$_} foreach grep /^SSL_/, keys %args;
    LWP::UserAgent::->new( agent => "$NAME/$VERSION", ssl_opts => \%ssl_opts );
} // die "Can't create LWP::UserAgent object";
$UA->default_header( 'Accept-Language' => 'en' );
my $NONCE;


#############################################################################
# Send an HTTP request to the ACME server.  If $json is defined, send
# its encoding as the request content, with "application/jose+json" as
# Content-Type.
#
sub request($$;$) {
    my ($method, $uri, $json) = @_;
    print STDERR "[$$] >>> $method $uri <<<\n" if $ENV{DEBUG};

    my $req = HTTP::Request::->new($method => $uri) or die "Can't $method $uri";
    if (defined $json) {
        $req->content_type('application/jose+json');
        $req->content(json()->encode($json));
    }
    my $r = $UA->request($req) or die "Can't $method $uri";
    $NONCE //= $r->header('Replay-Nonce'); # undef $NONCE if the header is missing
    print STDERR "[$$] >>> ", $r->status_line, "\n", $r->headers->as_string("\n") if $ENV{DEBUG};
    return $r;
}

# The request's Status Line; if the Content-Type is
# application/problem+json (RFC 7807), parse the decoded content as JSON
# and add the value of the 'detail' field to the Status Line.
sub request_status_line($) {
    my $r = shift;
    my $msg = $r->status_line;
    if (!$r->is_success() and $r->content_type() eq 'application/problem+json') {
        my $content = json()->decode($r->decoded_content());
        print STDERR json()->pretty->encode($content), "\n" if $ENV{DEBUG};
        $msg .= " (".$content->{detail}.")" if defined $content->{detail};
    }
    return $msg;
}

# The request's Retry-After header (RFC 7231 sec. 7.1.3), converted to
# waiting time in seconds.
sub request_retry_after($) {
    my $r = shift;
    my $v = $r->header('Retry-After');
    if (defined $v and $v !~ /\A\d+\z/) {
        $v = Date::Parse::str2time($v);
        if (defined $v) {
            $v = $v - time;
            undef $v if $v <= 0;
        }
    }
    return $v;
}

# Parse and return the request's decoded content as JSON; or print the
# Status Line and fail if the request failed.
# If $dump is set, also pretty-print the decoded content.
sub request_json_decode($;$$) {
    my $r = shift;
    my $dump = shift || $ENV{DEBUG};
    my $fh = shift // \*STDERR;
    die request_status_line($r), "\n" unless $r->is_success();
    my $content = $r->decoded_content();

    die "Content-Type: ".$r->content_type()." is not application/json\n"
        unless $r->content_type() eq 'application/json';

    my $json = json()->decode($content);
    print $fh (-t $fh ? (json()->pretty->encode($json)."\n") : $content)
        if $dump;
    return $json;
}


#############################################################################
# JSON-encode the hash reference $payload and send it to the ACME server
# $url encapsulated it in a JSON Web Signature (JWS).  $header MUST
# contain either "jwk" (JSON Web Key) or "kid" per RFC 8555 sec. 6.2
# https://tools.ietf.org/html/rfc8555
#
sub acme2($$;$) {
    my ($url, $header, $payload) = @_;

    # Produce the JSON Web Signature: RFC 7515 section 5
    $header->{alg} = $ALG;
    $header->{nonce} = $NONCE // die "Missing nonce\n";
    $header->{url} = $url;
    my $protected = encode_base64url(json()->encode($header));
    $payload = defined $payload ? encode_base64url(json()->encode($payload)) : "";

    $S->printflush($protected, ".", $payload, "\r\n");
    my $sig = $S->getline() // die "ERROR: No response from lacme-accountd\n";
    $sig =~ s/\r\n\z// or die;
    undef $NONCE; # consume the nonce

    # Flattened JSON Serialization, RFC 7515 section 7.2.2
    request(POST => $url, {
        payload => $payload,
        protected => $protected,
        signature => $sig
    });
}

# Like above, but always use "kid"
sub acme($;$) {
    my ($url, $payload) = @_;
    die "Missing KID\n" unless defined $KID;
    acme2($url, {kid => $KID}, $payload)
}

my $SERVER_URI = $CONFIG->{server} // '@@acmeapi_server@@';

my %RES;
# Get the resource URI from the directory
sub acme_resource($%) {
    my $r = shift;
    my %payload = @_;
    my %protected;

    unless (%RES) {
        # query the ACME directory to get resources URIs
        %RES = %{ request_json_decode(request(GET => $SERVER_URI)) };
        # send a HEAD request to the newNonce resource to get a fresh nonce
        die "Unknown resource 'newNonce'\n" unless defined $RES{newNonce};
        request(HEAD => $RES{newNonce});
    }
    my $uri = $RES{$r} // die "Unknown resource '$r'\n";

    if ($r eq "newAccount" or ($r eq "revokeCert" and !defined $KID)) {
        # per RFC 8555 sec. 6.2 these requests MUST have a JWK
        print STDERR "WARNING: lacme-accountd supplied an empty JWK; try removing 'keyid' ",
                     "setting from lacme-accountd.conf if the ACME resource request fails.\n"
            unless %$JWK;
        return acme2($uri, {jwk => $JWK}, \%payload);
    } else {
        # per RFC 8555 sec. 6.2 all other requests MUST have a KID
        return acme($uri, \%payload);
    }
}

# Set the key ID (registration URI)
sub set_kid(;$) {
    my $die = shift // 1;
    return if defined $KID; # already set
    my $r = acme_resource('newAccount', onlyReturnExisting => JSON::true );
    if ($r->is_success()) {
        $KID = $r->header('Location');
    } elsif ($die) {
        die request_status_line($r), "\n";
    }
}


#############################################################################
# account FLAGS [CONTACT ..]
#
if ($COMMAND eq 'account') {
    my $flags = shift @ARGV;

    my %h = ( contact => \@ARGV ) if @ARGV;
    $h{onlyReturnExisting}   = JSON::true    unless $flags & 0x01;
    $h{termsOfServiceAgreed} = JSON::true    if     $flags & 0x02;
    $h{status}               = "deactivated" if     $flags & 0x04;

    print STDERR "Requesting new registration ".(@ARGV ? ("for ".join(', ', @ARGV)) : "")."\n"
        if $flags & 0x01;

    my $r = acme_resource('newAccount', %h);
    # TODO: list account orders: https://github.com/letsencrypt/boulder/issues/3335

    print STDERR "Terms of Service: $RES{meta}->{termsOfService}\n"
        if defined $RES{meta} and defined $RES{meta}->{termsOfService};

    if ($r->is_success()) {
        $KID = $r->header('Location');
        print STDERR "Key ID: $KID\n";
        $r = acme($KID, \%h);
        request_json_decode($r, 1, \*STDOUT)
            if $r->is_success() and $r->content_type() eq 'application/json';
    }

    print STDERR request_status_line($r), "\n"
        if !$r->is_success() or $ENV{DEBUG};
    exit ($r->is_success() ? 0 : 1);
}


#############################################################################
# newOrder AUTHZ [AUTHZ ..]
#   Read the CSR (in DER format) from STDIN, print the cert (in PEM format
#   to STDOUT)
#
elsif ($COMMAND eq 'newOrder') {
    die unless @ARGV;
    my $timeout = $CONFIG->{timeout} // 30;
    my $csr = do { local $/ = undef; <STDIN> };

    set_kid();
    my @identifiers = map {{ type => 'dns', value => $_ }} @ARGV;
    my $r = acme_resource('newOrder', identifiers => \@identifiers);
    my $order = request_json_decode($r);
    my $orderurl = $r->header('Location');

    foreach (@{$order->{authorizations}}) {
        my $authz = request_json_decode(acme($_));
        next unless $authz->{status} eq 'pending';

        my $identifier = $authz->{identifier}->{value};
        my ($challenge) = grep {$_->{type} eq 'http-01'} @{$authz->{challenges} // []};
        die "Missing 'http-01' challenge in server response for '$identifier'\n"
            unless defined $challenge;

        die "Invalid challenge token ".($challenge->{token} // '')."\n"
            # ensure we don't write outside the cwd
            unless ($challenge->{token} // '') =~ /\A[A-Za-z0-9_\-]+\z/;

        my $keyAuthorization = $challenge->{token}.'.'.$JWK_thumbprint;

        # serve $keyAuthorization at http://$domain/.well-known/acme-challenge/$challenge->{token}
        if (sysopen(my $fh, $challenge->{token}, O_CREAT|O_EXCL|O_WRONLY, 0644)) {
            $fh->print($keyAuthorization);
            $fh->close() or die "close: $!";
        } elsif ($! == EEXIST) {
            print STDERR "WARNING: File exists: $challenge->{token}\n";
        } else {
            die "open($challenge->{token}): $!";
        }
        my $r = acme($challenge->{url}, {});
        request_json_decode($r);
    }

    # poll the order URL (to get the status of all challenges at once)
    # until the status become 'valid'
    my $orderstr = join(', ', map {uc($_->{type}) .":". $_->{value}} @identifiers);
    my $certuri;
    for (my $i = 0;;) {
        my $r = acme($orderurl);
        my $resp = request_json_decode($r);
        if (defined (my $problem = $resp->{error})) { # problem document (RFC 7807)
            my $msg = $problem->{status};
            $msg .= " " .$problem->{title}      if defined $problem->{title};
            $msg .= " (".$problem->{detail}.")" if defined $problem->{detail};
            die $msg, "\n";
        }
        my $status = $resp->{status};
        if (!defined $status or $status eq "invalid") {
            die "Error: Invalid order $orderstr\n";
        }
        elsif ($status eq "ready") {
            my $r = acme($order->{finalize}, {csr => encode_base64url($csr)});
            my $resp = request_json_decode($r);
            $certuri = $resp->{certificate};
            last;
        }
        elsif ($status eq "valid") {
            $certuri = $resp->{certificate} //
                die "Error: Missing \"certificate\" field in \"valid\" order\n";
            last;
        }
        elsif ($status ne "pending" and $status ne "processing") {
            warn "Unknown order status: $status\n";
        }

        my $retry_after = request_retry_after($r) // 1;
        print STDERR "Retrying after $retry_after seconds...\n";
        $i += $retry_after;
        die "Timeout exceeded while waiting for challenges to pass ($orderstr)\n"
            if $timeout > 0 and $i >= $timeout;
        sleep $retry_after;
    }

    # poll until the cert is available
    print STDERR "Certificate URI: $certuri\n";
    for (my $i = 0;;) {
        $r = acme($certuri);
        die request_status_line($r), "\n" unless $r->is_success();
        last unless $r->code == 202; # Accepted
        my $retry_after = request_retry_after($r) // 1;
        print STDERR "Retrying after $retry_after seconds...\n";
        $i += $retry_after;
        die "Timeout exceeded while waiting for certificate\n" if $timeout > 0 and $i >= $timeout;
        sleep $retry_after;
    }
    print $r->decoded_content();
}


#############################################################################
# revokeCert
#   The certificate to revoke is passed (in DER format) to STDIN; this
#   is needed since the ACME client might not have read access to the
#   X.509 file
#
elsif ($COMMAND eq 'revokeCert') {
    die if @ARGV;
    my $der = do { local $/ = undef; <STDIN> };
    close STDIN or die "close: $!";

    # RFC 8555 sec. 6.2: send a KID if the request is signed with the
    # acccount key, otherwise send a JWK
    # We have no way to know which of the account key or certificate key
    # is used, so we try to get a KID and fallback to sending the JWK
    set_kid(0);

    my $r = acme_resource('revokeCert', certificate => encode_base64url($der));
    exit 0 if $r->is_success();
    die request_status_line($r), "\n";
}