summaryrefslogtreecommitdiff
path: root/Master/tlpkg/TeXLive/TLCrypto.pm
blob: a75c8507b8ab8926f0b5d3feacfa27626674da05 (plain)
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
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
# $Id$
# TeXLive::TLCrypto.pm - handle checksums and signatures.
# Copyright 2016-2021 Norbert Preining
# This file is licensed under the GNU General Public License version 2
# or any later version.

package TeXLive::TLCrypto;

use Digest::MD5;

use TeXLive::TLConfig;
use TeXLive::TLUtils qw(debug ddebug win32 which platform
                        conv_to_w32_path tlwarn tldie);

my $svnrev = '$Revision$';
my $_modulerevision = ($svnrev =~ m/: ([0-9]+) /) ? $1 : "unknown";
sub module_revision { return $_modulerevision; }

=pod

=head1 NAME

C<TeXLive::TLCrypto> -- TeX Live checksums and cryptographic signatures

=head1 SYNOPSIS

  use TeXLive::TLCrypto;  # requires Digest::MD5 and Digest::SHA

=head2 Setup

  TeXLive::TLCrypto::setup_checksum_method();

=head2 Checksums

  TeXLive::TLCrypto::tlchecksum($path);
  TeXLive::TLCrypto::verify_checksum($file, $url);
  TeXLive::TLCrypto::verify_checksum_and_check_return($file, $url);

=head2 Signatures

  TeXLive::TLCrypto::setup_gpg();
  TeXLive::TLCrypto::verify_signature($file, $url);

=head1 DESCRIPTION

=cut

BEGIN {
  use Exporter ();
  use vars qw(@ISA @EXPORT_OK @EXPORT);
  @ISA = qw(Exporter);
  @EXPORT_OK = qw(
    &tlchecksum
    &tl_short_digest
    &verify_checksum
    &verify_checksum_and_check_return
    &setup_gpg
    &verify_signature
    %VerificationStatusDescription
    $VS_VERIFIED $VS_CHECKSUM_ERROR $VS_SIGNATURE_ERROR $VS_CONNECTION_ERROR
    $VS_UNSIGNED $VS_GPG_UNAVAILABLE $VS_PUBKEY_MISSING $VS_UNKNOWN
    $VS_EXPKEYSIG $VS_REVKEYSIG
  );
  @EXPORT = qw(
    %VerificationStatusDescription
    $VS_VERIFIED $VS_CHECKSUM_ERROR $VS_SIGNATURE_ERROR $VS_CONNECTION_ERROR
    $VS_UNSIGNED $VS_GPG_UNAVAILABLE $VS_PUBKEY_MISSING $VS_UNKNOWN
    $VS_EXPKEYSIG $VS_REVKEYSIG
  );
}

=pod

=over 4

=item C<< setup_checksum_method() >>

Tries to find a checksum method: check usability of C<Digest::SHA>,
then the programs C<openssl>, C<sha512sum>, and C<shasum>, in that
order.  On old-enough Macs, C<openssl> is present but does not have
the option C<-sha512>, while the separate program C<shasum> does suffice.

Returns the checksum method as a string, and also sets
C<<$::checksum_method>>, or false if none found.

=cut

sub setup_checksum_method {
  # make it a noop if already defined
  # the checksum method could also be "" meaning that there
  # is none. We do not need to check again. Thus we check
  # on defined.
  return ($::checksum_method) if defined($::checksum_method);
  # default is no checksum
  $::checksum_method = "";
  # for debugging
  # $::checksum_method = "sha512sum";
  # return($::checksum_method);
  # try to load Digest::SHA, and if that fails, use our own slow modules
  eval { 
    require Digest::SHA;
    Digest::SHA->import('sha512_hex');
    debug("Using checksum method digest::sha\n");
    $::checksum_method = "digest::sha";
  };
  if ($@ && ($^O !~ /^MSWin/i)) {
    # for unix like environments we test other programs (openssl, sha512sum,
    # shasum), too
    my $ret;

    # first for openssl dgst -sha512
    # old MacOS openssl does not support -sha512!
    $ret = system("openssl dgst -sha512 >/dev/null 2>&1 </dev/null" );
    if ($ret == 0) {
      debug("Using checksum method openssl\n");
      return($::checksum_method = "openssl");
    }

    # next for sha512sum, but this is not available on old MacOS
    if (TeXLive::TLUtils::which("sha512sum")) {
      debug("Using checksum method sha512sum\n");
      return($::checksum_method = "sha512sum");
    }

    # shasum for old Macs
    $ret = system("shasum -a 512 >/dev/null 2>&1 </dev/null" );
    if ($ret == 0) {
      debug("Using checksum method shasum\n");
      return($::checksum_method = "shasum");
    }

    debug("Cannot find usable checksum method!\n");
  }
  return($::checksum_method);
}


=pod

=item C<< tlchecksum($file) >>

Return checksum of C<$file>.

=cut

sub tlchecksum {
  my ($file) = @_;
  # this is here for the case that a script forgets to
  # set up the checksum method!
  if (!$::checksum_method) {
    setup_checksum_method();
  }
  tldie("TLCRYPTO::tlchecksum: no checksum method available\n")
    if (!$::checksum_method);

  if (-r $file) {
    my ($out, $ret);
    if ($::checksum_method eq "openssl") {
      ($out, $ret) = TeXLive::TLUtils::run_cmd("openssl dgst -sha512 $file");
      chomp($out);
    } elsif ($::checksum_method eq "sha512sum") {
      ($out, $ret) = TeXLive::TLUtils::run_cmd("sha512sum $file");
      chomp($out);
    } elsif ($::checksum_method eq "shasum") {
      ($out, $ret) = TeXLive::TLUtils::run_cmd("shasum -a 512 $file");
      chomp($out);
    } elsif ($::checksum_method eq "digest::sha") {
      open(FILE, $file) || die "open($file) failed: $!";
      binmode(FILE);
      $out = Digest::SHA->new(512)->addfile(*FILE)->hexdigest;
      close(FILE);
      $ret = 0;
    } else {
      tldie("TLCRYPTO::tlchecksum: unknown checksum program: $::checksum_method\n");
    }
    if ($ret != 0) {
      tlwarn("TLCRYPTO::tlchecksum: cannot compute checksum: $file\n");
      return "";
    }
    ddebug("tlchecksum: out = $out\n");
    my $cs;
    if ($::checksum_method eq "openssl") {
      (undef,$cs) = split(/= /,$out);
    } elsif ($::checksum_method eq "sha512sum") {
      ($cs,undef) = split(' ',$out);
    } elsif ($::checksum_method eq "shasum") {
      ($cs,undef) = split(' ',$out);
    } elsif ($::checksum_method eq "digest::sha") {
      $cs = $out;
    }
    debug("tlchecksum($file): ===$cs===\n");
    if (length($cs) != 128) {
      tlwarn("TLCRYPTO::tlchecksum: unexpected output from $::checksum_method:"
             . " $out\n");
      return "";
    }
    return $cs;
  } else {
    tlwarn("TLCRYPTO::tlchecksum: given file not readable: $file\n");
    return "";
  }
}

# sub tlchecksum {
#   my ($file) = @_;
#   if (-r $file) {
#     open(FILE, $file) || die "open($file) failed: $!";
#     binmode(FILE);
#     my $cshash = $dig->new(512)->addfile(*FILE)->hexdigest;
#     close(FILE);
#     return $cshash;
#   } else {
#     tlwarn("tlchecksum: given file not readable: $file\n");
#     return "";
#   }
# } 

=pod

=item C<< tl_short_digest($str) >>

Return short digest (MD5) of C<$str>.

=cut

sub tl_short_digest { return (Digest::MD5::md5_hex(shift)); }

# emacs-page
=pod

=item C<< verify_checksum_and_check_return($file, $tlpdburl [, $is_main, $localcopymode ]) >>

Calls C<<verify_checksum>> and checks the various return values
for critical errors, and dies if necessary.

If C<$is_main> is given and true, an unsigned tlpdb is considered
fatal. If C<$localcopymode> is given and true, do not die for 
checksum and connection errors, thus allowing for re-downloading
of a copy.

=cut

sub verify_checksum_and_check_return {
  my ($file, $path, $is_main, $localcopymode) = @_;
  my ($r, $m) = verify_checksum($file, "$path.$ChecksumExtension");
  if ($r == $VS_CHECKSUM_ERROR) {
    if (!$localcopymode) {
      tldie("$0: checksum error when downloading $file from $path: $m\n");
    }
    return(0, $r);
  } elsif ($r == $VS_SIGNATURE_ERROR) {
    tldie("$0: signature verification error of $file from $path: $m\n");
  } elsif ($r == $VS_CONNECTION_ERROR) {
    if ($localcopymode) {
      return(0, $r);
    } else {
      tldie("$0: cannot download: $m\n");
    }
  } elsif ($r == $VS_UNSIGNED) {
    if ($is_main) {
      tldie("$0: main database at $path is not signed: $m\n");
    }
    debug("$0: remote database checksum is not signed, continuing anyway\n");
    return(0, $r);
  } elsif ($r == $VS_EXPKEYSIG) {
    debug("$0: good signature bug gpg key expired, continuing anyway!\n");
    return(0, $r);
  } elsif ($r == $VS_REVKEYSIG) {
    debug("$0: good signature but from revoked gpg key, continuing anyway!\n");
    return(0, $r);
  } elsif ($r == $VS_GPG_UNAVAILABLE) {
    debug("$0: TLPDB: no gpg available, continuing anyway!\n");
    return(0, $r);
  } elsif ($r == $VS_PUBKEY_MISSING) {
    debug("$0: TLPDB: pubkey missing, continuing anyway!\n");
    return(0, $r);
  } elsif ($r == $VS_VERIFIED) {
    return(1, $r);
  } else {
    tldie("$0: unexpected return value from verify_checksum: $r\n");
  }
  # we should never come here, but just to be sure
  return(0, $r);
}



# emacs-page
=pod

=item C<< verify_checksum($file, $checksum_url) >>

Verifies that C<$file> has checksum C<$checksum_url>, and if gpg is
available also verifies that the checksum is signed.

Returns 
C<$VS_VERIFIED> on success, 
C<$VS_CONNECTION_ERROR> on connection error,
C<$VS_UNSIGNED> on missing signature file, 
C<$VS_GPG_UNAVAILABLE> if no gpg program is available,
C<$VS_PUBKEY_MISSING> if the pubkey is not available, 
C<$VS_CHECKSUM_ERROR> on checksum errors, 
C<$VS_EXPKEYSIG> if the signature is good but was made with an expired key,
C<$VS_REVKEYSIG> if the signature is good but was made with a revoked key,
and C<$VS_SIGNATURE_ERROR> on signature errors.
In case of errors returns an informal message as second argument.

=cut

sub verify_checksum {
  my ($file, $checksum_url) = @_;
  # don't do anything if we cannot determine a checksum method
  # return -2 which is as much as missing signature
  return($VS_UNSIGNED, "no checksum method found") if (!$::checksum_method);
  my $checksum_file
    = TeXLive::TLUtils::download_to_temp_or_file($checksum_url);

  # next step is verification of tlpdb checksum with checksum file
  # existenc of checksum_file was checked above
  if (!$checksum_file) {
    debug("verify_checksum: download did not succeed for $checksum_url\n");
    return($VS_CONNECTION_ERROR, "download did not succeed: $checksum_url");
  }

  # check that we have a non-trivial size for the checksum file
  # the size should be at least 128 + 1 + length(filename) > 129
  {
    my $css = -s $checksum_file;
    if ($css <= 128) {
      debug("verify_checksum: size of checksum file suspicious: $css\n");
      return($VS_CONNECTION_ERROR, "download corrupted: $checksum_url");
    }
  }

  # check the signature
  my ($ret, $msg) = verify_signature($checksum_file, $checksum_url);

  if ($ret != 0) {
    debug("verify_checksum: returning $ret and $msg\n");
    return ($ret, $msg)
  }

  # verify local data
  open $cs_fh, "<$checksum_file" or die("cannot read file: $!");
  if (read ($cs_fh, $remote_digest, $ChecksumLength) != $ChecksumLength) {
    close($cs_fh);
    debug("verify_checksum: incomplete read from\n  $checksum_file\nfor\n  $file\nand\n  $checksum_url\n");
    return($VS_CHECKSUM_ERROR, "incomplete read from $checksum_file");
  } else {
    close($cs_fh);
    debug("verify_checksum: found remote digest\n  $remote_digest\nfrom\n  $checksum_file\nfor\n  $file\nand\n  $checksum_url\n");
  }
  $local_digest = tlchecksum($file);
  debug("verify_checksum: local_digest = $local_digest\n");
  if ($local_digest ne $remote_digest) {
    return($VS_CHECKSUM_ERROR, "digest disagree");
  }

  # we are still here, so checksum also succeeded
  debug("checksum of local copy identical with remote hash\n");

  return($VS_VERIFIED);
}

# emacs-page
=pod

=item C<< setup_gpg() >>

Tries to set up gpg command line C<$::gpg> used for verification of
downloads. Checks for the environment variable C<TL_GNUPG>; if that
envvar is not set, first C<gpg>, then C<gpg2>, then, on Windows only,
C<tlpkg/installer/gpg/gpg.exe> is looked for.  Further adaptation of the
invocation of C<gpg> can be done using the two enviroment variables
C<TL_GNUPGHOME>, which is passed to C<gpg> with C<--homedir>, and
C<TL_GNUPGARGS>, which replaces the default arguments
C<--no-secmem-warning --no-permission-warning>.

Returns 1/0 on success/failure.

=cut

sub setup_gpg {
  my $master = shift;
  my $found = 0;
  my $prg;
  if ($ENV{'TL_GNUPG'}) {
    # if envvar is set, don't look for anything else.
    $prg = test_one_gpg($ENV{'TL_GNUPG'});
    $found = 1 if ($prg);
  } else {
    # no envvar, look for gpg
    $prg = test_one_gpg('gpg');
    $found = 1 if ($prg);
  
    # no gpg, look for gpg2
    if (!$found) {
      $prg = test_one_gpg('gpg2');
      $found = 1 if ($prg);
    }
    if (!$found) {
      # test also a shipped version from tlgpg
      my $p = "$master/tlpkg/installer/gpg/gpg." .
        ($^O =~ /^MSWin/i ? "exe" : platform()) ;
      debug("Testing for gpg in $p\n");
      if (-r $p) {
        if ($^O =~ /^MSWin/i) {
          $prg = conv_to_w32_path($p);
        } else {
          $prg = "\"$p\"";
        }
        $found = 1;
      }
    }
  }
  return 0 if (!$found);

  # $prg is already properly quoted!

  # ok, we found one
  # Set up the gpg invocation:
  my $gpghome = ($ENV{'TL_GNUPGHOME'} ? $ENV{'TL_GNUPGHOME'} : 
                                        "$master/tlpkg/gpg" );
  $gpghome =~ s!/!\\!g if win32();
  my $gpghome_quote = "\"$gpghome\"";
  # mind the final space for following args
  $::gpg = "$prg --homedir $gpghome_quote ";
  #
  # check for additional keyring
  # originally we wanted to use TEXMFSYSCONFIG, but gnupg on Windows
  # is so stupid that it *prepends* GNUPGHOME to paths starting with
  # a drive letter like c:/
  # Thus we switch to using repository-keys.gpg in GNUPGHOME!
  my $addkr = "$gpghome/repository-keys.gpg";
  if (-r $addkr) {
    debug("setup_gpg: using additional keyring $addkr\n");
    $::gpg .= "--keyring repository-keys.gpg ";
  }
  if ($ENV{'TL_GNUPGARGS'}) {
    $::gpg .= $ENV{'TL_GNUPGARGS'};
  } else {
    $::gpg .= "--no-secmem-warning --no-permission-warning --lock-never ";
  }
  debug("gpg command line: $::gpg\n");
  return 1;
}

sub test_one_gpg {
  my $prg = shift;
  my $cmdline;
  debug("Testing for gpg in $prg\n");
  if ($^O =~ /^MSWin/i) {
    # Perl on Windows somehow does not allow calling a program
    # without a full path - at least a call to "gpg" tells me
    # that "c:/Users/norbert/gpg" is not recognized ...
    # consequence - use which!
    $prg = which($prg);
    return "" if (!$prg);
    $prg = conv_to_w32_path($prg);
    $cmdline = "$prg --version >nul 2>&1";
  } else {
    $cmdline = "$prg --version >/dev/null 2>&1";
  }
  my $ret = system($cmdline);
  if ($ret == 0) {
    debug(" ... gpg ok! [$cmdline]\n");
    return $prg;
  } else {
    debug(" ... gpg not ok! [$cmdline]\n");
    return "";
  }
}

# emacs-page
=pod

=item C<< verify_signature($file, $url) >>

Verifies a download of C<$url> into C<$file> by cheking the 
gpg signature in C<$url.asc>.

Returns 
$VS_VERIFIED on success, 
$VS_REVKEYSIG on good signature but from revoked key,
$VS_EXPKEYSIG on good signature but from expired key,
$VS_UNSIGNED on missing signature file, 
$VS_SIGNATURE_ERROR on signature error,
$VS_GPG_UNAVAILABLE if no gpg is available, and 
$VS_PUBKEY_MISSING if a pubkey is missing.
In case of errors returns an informal message as second argument.

=cut

sub verify_signature {
  my ($file, $url) = @_;
  my $signature_url = "$url.asc";

  # if we have $::gpg set, we try to verify cryptographic signatures
  if ($::gpg) {
    my $signature_file
      = TeXLive::TLUtils::download_to_temp_or_file($signature_url);
    if ($signature_file) {
      {
        # we expect a signature to be at least
        # 30 header line + 30 footer line + 256 > 300
        my $sigsize = -s $signature_file;
        if ($sigsize < 300) {
          debug("cryptographic signature seems to be corrupted (size $sigsize<300): $signature_url, $signature_file\n");
          return($VS_UNSIGNED, "cryptographic signature download seems to be corrupted (size $sigsize<300)");
        }
      }
      # check also the first line of the signature file for
      # -----BEGIN PGP SIGNATURE-----
      {
        open my $file, '<', $signature_file;
        chomp(my $firstLine = <$file>);
        close $file;
        if ($firstLine !~ m/^-----BEGIN PGP SIGNATURE-----/) {
          debug("cryptographic signature seems to be corrupted (first line not signature): $signature_url, $signature_file, $firstLine\n");
          return($VS_UNSIGNED, "cryptographic signature download seems to be corrupted (first line of $signature_url not signature: $firstLine)");
        }
      }
      my ($ret, $out) = gpg_verify_signature($file, $signature_file);
      if ($ret == $VS_VERIFIED) {
        # no need to show the output
        debug("cryptographic signature of $url verified\n");
        return($VS_VERIFIED);
      } elsif ($ret == $VS_PUBKEY_MISSING) {
        return($VS_PUBKEY_MISSING, $out);
      } elsif ($ret == $VS_EXPKEYSIG) {
        return($VS_EXPKEYSIG, $out);
      } elsif ($ret == $VS_REVKEYSIG) {
        return($VS_REVKEYSIG, $out);
      } else {
        return($VS_SIGNATURE_ERROR, <<GPGERROR);
cryptographic signature verification of
  $file
against
  $signature_url
failed. Output was:
$out
Please try from a different mirror and/or wait a few minutes
and try again; usually this is because of transient updates.
If problems persist, feel free to report to texlive\@tug.org.
GPGERROR
      }
    } else {
      debug("no access to cryptographic signature $signature_url\n");
      return($VS_UNSIGNED, "no access to cryptographic signature");
    }
  } else {
    debug("gpg prog not defined, no checking of signatures\n");
    # we return 0 (= success) if not gpg is available
    return($VS_GPG_UNAVAILABLE, "no gpg available");
  }
  # not reached
  return ($VS_UNKNOWN);
}

=pod

=item C<< gpg_verify_signature($file, $sig) >>

Internal routine running gpg to verify signature C<$sig> of C<$file>.

=cut

sub gpg_verify_signature {
  my ($file, $sig) = @_;
  my ($file_quote, $sig_quote);
  if (win32()) {
    $file =~ s!/!\\!g;
    $sig =~ s!/!\\!g;
  }
  $file_quote = TeXLive::TLUtils::quotify_path_with_spaces ($file);
  $sig_quote = TeXLive::TLUtils::quotify_path_with_spaces ($sig);
  my ($status_fh, $status_file) = TeXLive::TLUtils::tl_tmpfile();
  close($status_fh);
  my ($out, $ret)
    = TeXLive::TLUtils::run_cmd("$::gpg --status-file \"$status_file\" --verify $sig_quote $file_quote 2>&1");
  # read status file
  open($status_fd, "<", $status_file) || die("Cannot open status file: $!");
  my @status_lines = <$status_fd>;
  close($status_fd);
  chomp(@status_lines);
  debug(join("\n", "STATUS OUTPUT", @status_lines));
  if ($ret == 0) {
    # verification still might return success but key is expired!
    if (grep(/EXPKEYSIG/, @status_lines)) {
      return($VS_EXPKEYSIG, "expired key");
    }
    if (grep(/REVKEYSIG/, @status_lines)) {
      return($VS_REVKEYSIG, "revoked key");
    }
    debug("verification succeeded, output:\n$out\n");
    return ($VS_VERIFIED, $out);
  } else {
    my @nopb = grep(/^\[GNUPG:\] NO_PUBKEY /, @status_lines);
    if (@nopb) {
      my $mpk = $nopb[-1];
      $mpk =~ s/^\[GNUPG:\] NO_PUBKEY //;
      debug("missing pubkey $mpk\n");
      return ($VS_PUBKEY_MISSING, "missing pubkey $mpk");
    }
    # we could do more checks on what is the actual problem here!
    return ($VS_SIGNATURE_ERROR, $out);
  }
}

=pod

=item C<< %VerificationStatusDescription >>

Provides a textual representation for the verification status values.

=cut

our $VS_VERIFIED = 0;
our $VS_CHECKSUM_ERROR = 1;
our $VS_SIGNATURE_ERROR = 2;
our $VS_CONNECTION_ERROR = -1;
our $VS_UNSIGNED = -2;
our $VS_GPG_UNAVAILABLE = -3;
our $VS_PUBKEY_MISSING = -4;
our $VS_EXPKEYSIG = -5;
our $VS_EXPSIG = -6;
our $VS_REVKEYSIG = -7;
our $VS_UNKNOWN = -100;

our %VerificationStatusDescription = (
  $VS_VERIFIED         => 'verified',
  $VS_CHECKSUM_ERROR   => 'checksum error',
  $VS_SIGNATURE_ERROR  => 'signature error',
  $VS_CONNECTION_ERROR => 'connection error',
  $VS_UNSIGNED         => 'unsigned',
  $VS_GPG_UNAVAILABLE  => 'gpg unavailable',
  $VS_PUBKEY_MISSING   => 'pubkey missing',
  $VS_EXPKEYSIG        => 'valid signature with expired key',
  $VS_EXPSIG           => 'valid but expired signature',
  $VS_UNKNOWN          => 'unknown',
);

=back
=cut

1;
__END__

=head1 SEE ALSO

The modules L<TeXLive::Config>, L<TeXLive::TLUtils>, etc.,
and the documentation in the repository: C<Master/tlpkg/doc/>.
Also the standard modules L<Digest::MD5> and L<Digest::SHA>.

=head1 AUTHORS AND COPYRIGHT

This script and its documentation were written for the TeX Live
distribution (L<https://tug.org/texlive>) and both are licensed under the
GNU General Public License Version 2 or later.

=cut

### Local Variables:
### perl-indent-level: 2
### tab-width: 2
### indent-tabs-mode: nil
### End:
# vim:set tabstop=2 expandtab: #