summaryrefslogtreecommitdiff
path: root/src/openvpn/ssl_verify.c
blob: e651a8e0f52f76ad50e6190066d13f2ec307d942 (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
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
/*
 *  OpenVPN -- An application to securely tunnel IP networks
 *             over a single TCP/UDP port, with support for SSL/TLS-based
 *             session authentication and key exchange,
 *             packet encryption, packet authentication, and
 *             packet compression.
 *
 *  Copyright (C) 2002-2010 OpenVPN Technologies, Inc. <sales@openvpn.net>
 *  Copyright (C) 2010 Fox Crypto B.V. <openvpn@fox-it.com>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2
 *  as published by the Free Software Foundation.
 *
 *  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 (see the file COPYING included with this
 *  distribution); if not, write to the Free Software Foundation, Inc.,
 *  59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

/**
 * @file Control Channel Verification Module
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#elif defined(_MSC_VER)
#include "config-msvc.h"
#endif

#include "syshead.h"

#if defined(ENABLE_CRYPTO) && defined(ENABLE_SSL)

#include "misc.h"
#include "manage.h"
#include "ssl_verify.h"
#include "ssl_verify_backend.h"

#ifdef ENABLE_CRYPTO_OPENSSL
#include "ssl_verify_openssl.h"
#endif

/** Maximum length of common name */
#define TLS_USERNAME_LEN 64

/** Legal characters in an X509 name with --compat-names */
#define X509_NAME_CHAR_CLASS   (CC_ALNUM|CC_UNDERBAR|CC_DASH|CC_DOT|CC_AT|CC_SLASH|CC_COLON|CC_EQUAL)

/** Legal characters in a common name with --compat-names */
#define COMMON_NAME_CHAR_CLASS (CC_ALNUM|CC_UNDERBAR|CC_DASH|CC_DOT|CC_AT|CC_SLASH)

static void
string_mod_remap_name (char *str, const unsigned int restrictive_flags)
{
  if (compat_flag (COMPAT_FLAG_QUERY | COMPAT_NAMES)
      && !compat_flag (COMPAT_FLAG_QUERY | COMPAT_NO_NAME_REMAPPING))
    string_mod (str, restrictive_flags, 0, '_');
  else
    string_mod (str, CC_PRINT, CC_CRLF, '_');
}

/*
 * Export the untrusted IP address and port to the environment
 */
static void
setenv_untrusted (struct tls_session *session)
{
  setenv_link_socket_actual (session->opt->es, "untrusted", &session->untrusted_addr, SA_IP_PORT);
}

/*
 * Remove authenticated state from all sessions in the given tunnel
 */
static void
tls_deauthenticate (struct tls_multi *multi)
{
  if (multi)
    {
      int i, j;
      for (i = 0; i < TM_SIZE; ++i)
	for (j = 0; j < KS_SIZE; ++j)
	  multi->session[i].key[j].authenticated = false;
    }
}

/*
 * Set the given session's common_name
 */
static void
set_common_name (struct tls_session *session, const char *common_name)
{
  if (session->common_name)
    {
      free (session->common_name);
      session->common_name = NULL;
#ifdef ENABLE_PF
      session->common_name_hashval = 0;
#endif
    }
  if (common_name)
    {
      /* FIXME: Last alloc will never be freed */
      session->common_name = string_alloc (common_name, NULL);
#ifdef ENABLE_PF
      {
	const uint32_t len = (uint32_t) strlen (common_name);
	if (len)
	  session->common_name_hashval = hash_func ((const uint8_t*)common_name, len+1, 0);
	else
	  session->common_name_hashval = 0;
      }
#endif
    }
}

/*
 * Retrieve the common name for the given tunnel's active session. If the
 * common name is NULL or empty, return NULL if null is true, or "UNDEF" if
 * null is false.
 */
const char *
tls_common_name (const struct tls_multi *multi, const bool null)
{
  const char *ret = NULL;
  if (multi)
    ret = multi->session[TM_ACTIVE].common_name;
  if (ret && strlen (ret))
    return ret;
  else if (null)
    return NULL;
  else
    return "UNDEF";
}

/*
 * Lock the common name for the given tunnel.
 */
void
tls_lock_common_name (struct tls_multi *multi)
{
  const char *cn = multi->session[TM_ACTIVE].common_name;
  if (cn && !multi->locked_cn)
    multi->locked_cn = string_alloc (cn, NULL);
}

/*
 * Lock the username for the given tunnel
 */
static bool
tls_lock_username (struct tls_multi *multi, const char *username)
{
  if (multi->locked_username)
    {
      if (!username || strcmp (username, multi->locked_username))
	{
	  msg (D_TLS_ERRORS, "TLS Auth Error: username attempted to change from '%s' to '%s' -- tunnel disabled",
	       multi->locked_username,
	       np(username));

	  /* disable the tunnel */
	  tls_deauthenticate (multi);
	  return false;
	}
    }
  else
    {
      if (username)
	multi->locked_username = string_alloc (username, NULL);
    }
  return true;
}

const char *
tls_username (const struct tls_multi *multi, const bool null)
{
  const char *ret = NULL;
  if (multi)
    ret = multi->locked_username;
  if (ret && strlen (ret))
    return ret;
  else if (null)
    return NULL;
  else
    return "UNDEF";
}

void
cert_hash_remember (struct tls_session *session, const int error_depth, const unsigned char *sha1_hash)
{
  if (error_depth >= 0 && error_depth < MAX_CERT_DEPTH)
    {
      if (!session->cert_hash_set)
	ALLOC_OBJ_CLEAR (session->cert_hash_set, struct cert_hash_set);
      if (!session->cert_hash_set->ch[error_depth])
	ALLOC_OBJ (session->cert_hash_set->ch[error_depth], struct cert_hash);
      {
	struct cert_hash *ch = session->cert_hash_set->ch[error_depth];
	memcpy (ch->sha1_hash, sha1_hash, SHA_DIGEST_LENGTH);
      }
    }
}

#if 0
static void
cert_hash_print (const struct cert_hash_set *chs, int msglevel)
{
  struct gc_arena gc = gc_new ();
  msg (msglevel, "CERT_HASH");
  if (chs)
    {
      int i;
      for (i = 0; i < MAX_CERT_DEPTH; ++i)
	{
	  const struct cert_hash *ch = chs->ch[i];
	  if (ch)
	    msg (msglevel, "%d:%s", i, format_hex(ch->sha1_hash, SHA_DIGEST_LENGTH, 0, &gc));
	}
    }
  gc_free (&gc);
}
#endif

void
cert_hash_free (struct cert_hash_set *chs)
{
  if (chs)
    {
      int i;
      for (i = 0; i < MAX_CERT_DEPTH; ++i)
	free (chs->ch[i]);
      free (chs);
    }
}

static bool
cert_hash_compare (const struct cert_hash_set *chs1, const struct cert_hash_set *chs2)
{
  if (chs1 && chs2)
    {
      int i;
      for (i = 0; i < MAX_CERT_DEPTH; ++i)
	{
	  const struct cert_hash *ch1 = chs1->ch[i];
	  const struct cert_hash *ch2 = chs2->ch[i];

	  if (!ch1 && !ch2)
	    continue;
	  else if (ch1 && ch2 && !memcmp (ch1->sha1_hash, ch2->sha1_hash, SHA_DIGEST_LENGTH))
	    continue;
	  else
	    return false;
	}
      return true;
    }
  else if (!chs1 && !chs2)
    return true;
  else
    return false;
}

static struct cert_hash_set *
cert_hash_copy (const struct cert_hash_set *chs)
{
  struct cert_hash_set *dest = NULL;
  if (chs)
    {
      int i;
      ALLOC_OBJ_CLEAR (dest, struct cert_hash_set);
      for (i = 0; i < MAX_CERT_DEPTH; ++i)
	{
	  const struct cert_hash *ch = chs->ch[i];
	  if (ch)
	    {
	      ALLOC_OBJ (dest->ch[i], struct cert_hash);
	      memcpy (dest->ch[i]->sha1_hash, ch->sha1_hash, SHA_DIGEST_LENGTH);
	    }
	}
    }
  return dest;
}
void
tls_lock_cert_hash_set (struct tls_multi *multi)
{
  const struct cert_hash_set *chs = multi->session[TM_ACTIVE].cert_hash_set;
  if (chs && !multi->locked_cert_hash_set)
    multi->locked_cert_hash_set = cert_hash_copy (chs);
}

/*
 * Returns the string associated with the given certificate type.
 */
static const char *
print_nsCertType (int type)
{
  switch (type)
    {
    case NS_CERT_CHECK_SERVER:
      return "SERVER";
    case NS_CERT_CHECK_CLIENT:
      return "CLIENT";
    default:
      return "?";
    }
}

/*
 * Verify the peer's certificate fields.
 *
 * @param opt the tls options to verify against
 * @param peer_cert the peer's certificate
 * @param subject the peer's extracted subject name
 * @param subject the peer's extracted common name
 */
static result_t
verify_peer_cert(const struct tls_options *opt, openvpn_x509_cert_t *peer_cert,
    const char *subject, const char *common_name)
{
  /* verify certificate nsCertType */
  if (opt->ns_cert_type != NS_CERT_CHECK_NONE)
    {
      if (SUCCESS == x509_verify_ns_cert_type (peer_cert, opt->ns_cert_type))
	{
	  msg (D_HANDSHAKE, "VERIFY OK: nsCertType=%s",
	       print_nsCertType (opt->ns_cert_type));
	}
      else
	{
	  msg (D_HANDSHAKE, "VERIFY nsCertType ERROR: %s, require nsCertType=%s",
	       subject, print_nsCertType (opt->ns_cert_type));
	  return FAILURE;		/* Reject connection */
	}
    }

#if OPENSSL_VERSION_NUMBER >= 0x00907000L || ENABLE_CRYPTO_POLARSSL

  /* verify certificate ku */
  if (opt->remote_cert_ku[0] != 0)
    {
      if (SUCCESS == x509_verify_cert_ku (peer_cert, opt->remote_cert_ku, MAX_PARMS))
	{
	  msg (D_HANDSHAKE, "VERIFY KU OK");
	}
        else
        {
	  msg (D_HANDSHAKE, "VERIFY KU ERROR");
          return FAILURE;		/* Reject connection */
	}
    }

  /* verify certificate eku */
  if (opt->remote_cert_eku != NULL)
    {
      if (SUCCESS == x509_verify_cert_eku (peer_cert, opt->remote_cert_eku))
        {
	  msg (D_HANDSHAKE, "VERIFY EKU OK");
	}
      else
	{
	  msg (D_HANDSHAKE, "VERIFY EKU ERROR");
          return FAILURE;		/* Reject connection */
	}
    }

#endif /* OPENSSL_VERSION_NUMBER */

  /* verify X509 name or username against --verify-x509-[user]name */
  if (opt->verify_x509_type != VERIFY_X509_NONE)
    {
      if ( (opt->verify_x509_type == VERIFY_X509_SUBJECT_DN
            && strcmp (opt->verify_x509_name, subject) == 0)
        || (opt->verify_x509_type == VERIFY_X509_SUBJECT_RDN
            && strcmp (opt->verify_x509_name, common_name) == 0)
        || (opt->verify_x509_type == VERIFY_X509_SUBJECT_RDN_PREFIX
            && strncmp (opt->verify_x509_name, common_name,
                        strlen (opt->verify_x509_name)) == 0) )
	msg (D_HANDSHAKE, "VERIFY X509NAME OK: %s", subject);
      else
	{
	  msg (D_HANDSHAKE, "VERIFY X509NAME ERROR: %s, must be %s",
	       subject, opt->verify_x509_name);
	  return FAILURE;		/* Reject connection */
	}
    }

  return SUCCESS;
}

/*
 * Export the subject, common_name, and raw certificate fields to the
 * environment for later verification by scripts and plugins.
 */
static void
verify_cert_set_env(struct env_set *es, openvpn_x509_cert_t *peer_cert, int cert_depth,
    const char *subject, const char *common_name
#ifdef ENABLE_X509_TRACK
    , const struct x509_track *x509_track
#endif
    )
{
  char envname[64];
  char *serial = NULL;
  struct gc_arena gc = gc_new ();

  /* Save X509 fields in environment */
#ifdef ENABLE_X509_TRACK
  if (x509_track)
    x509_setenv_track (x509_track, es, cert_depth, peer_cert);
  else
#endif
    x509_setenv (es, cert_depth, peer_cert);

  /* export subject name string as environmental variable */
  openvpn_snprintf (envname, sizeof(envname), "tls_id_%d", cert_depth);
  setenv_str (es, envname, subject);

#if 0
  /* export common name string as environmental variable */
  openvpn_snprintf (envname, sizeof(envname), "tls_common_name_%d", cert_depth);
  setenv_str (es, envname, common_name);
#endif

#ifdef ENABLE_EUREPHIA
  /* export X509 cert SHA1 fingerprint */
  {
    unsigned char *sha1_hash = x509_get_sha1_hash(peer_cert, &gc);

    openvpn_snprintf (envname, sizeof(envname), "tls_digest_%d", cert_depth);
    setenv_str (es, envname, format_hex_ex(sha1_hash, SHA_DIGEST_LENGTH, 0, 1,
					  ":", &gc));
  }
#endif

  /* export serial number as environmental variable */
  serial = x509_get_serial(peer_cert, &gc);
  openvpn_snprintf (envname, sizeof(envname), "tls_serial_%d", cert_depth);
  setenv_str (es, envname, serial);

  gc_free(&gc);
}

/*
 * call --tls-verify plug-in(s)
 */
static result_t
verify_cert_call_plugin(const struct plugin_list *plugins, struct env_set *es,
    int cert_depth, openvpn_x509_cert_t *cert, char *subject)
{
  if (plugin_defined (plugins, OPENVPN_PLUGIN_TLS_VERIFY))
    {
      int ret;
      struct argv argv = argv_new ();

      argv_printf (&argv, "%d %s", cert_depth, subject);

      ret = plugin_call_ssl (plugins, OPENVPN_PLUGIN_TLS_VERIFY, &argv, NULL, es, cert_depth, cert);

      argv_reset (&argv);

      if (ret == OPENVPN_PLUGIN_FUNC_SUCCESS)
	{
	  msg (D_HANDSHAKE, "VERIFY PLUGIN OK: depth=%d, %s",
	      cert_depth, subject);
	}
      else
	{
	  msg (D_HANDSHAKE, "VERIFY PLUGIN ERROR: depth=%d, %s",
	      cert_depth, subject);
	  return FAILURE;		/* Reject connection */
	}
    }
  return SUCCESS;
}

static const char *
verify_cert_export_cert(openvpn_x509_cert_t *peercert, const char *tmp_dir, struct gc_arena *gc)
{
  FILE *peercert_file;
  const char *peercert_filename="";

  if(!tmp_dir)
      return NULL;

  /* create tmp file to store peer cert */
  peercert_filename = create_temp_file (tmp_dir, "pcf", gc);

  /* write peer-cert in tmp-file */
  peercert_file = fopen(peercert_filename, "w+");
  if(!peercert_file)
    {
      msg (M_ERR, "Failed to open temporary file : %s", peercert_filename);
      return NULL;
    }

  if (SUCCESS != x509_write_pem(peercert_file, peercert))
      msg (M_ERR, "Error writing PEM file containing certificate");

  fclose(peercert_file);
  return peercert_filename;
}


/*
 * run --tls-verify script
 */
static result_t
verify_cert_call_command(const char *verify_command, struct env_set *es,
    int cert_depth, openvpn_x509_cert_t *cert, char *subject, const char *verify_export_cert)
{
  const char *tmp_file = NULL;
  int ret;
  struct gc_arena gc = gc_new();
  struct argv argv = argv_new ();

  setenv_str (es, "script_type", "tls-verify");

  if (verify_export_cert)
    {
      if ((tmp_file=verify_cert_export_cert(cert, verify_export_cert, &gc)))
       {
         setenv_str(es, "peer_cert", tmp_file);
       }
    }

  argv_printf (&argv, "%sc %d %s", verify_command, cert_depth, subject);

  argv_msg_prefix (D_TLS_DEBUG, &argv, "TLS: executing verify command");
  ret = openvpn_run_script (&argv, es, 0, "--tls-verify script");

  if (verify_export_cert)
    {
       if (tmp_file)
          platform_unlink(tmp_file);
    }

  gc_free(&gc);
  argv_reset (&argv);

  if (ret)
    {
      msg (D_HANDSHAKE, "VERIFY SCRIPT OK: depth=%d, %s",
	   cert_depth, subject);
      return SUCCESS;
    }

  msg (D_HANDSHAKE, "VERIFY SCRIPT ERROR: depth=%d, %s",
       cert_depth, subject);
  return FAILURE;		/* Reject connection */
}

/*
 * check peer cert against CRL directory
 */
static result_t
verify_check_crl_dir(const char *crl_dir, openvpn_x509_cert_t *cert)
{
  result_t ret = FAILURE;
  char fn[256];
  int fd = -1;
  struct gc_arena gc = gc_new();

  char *serial = x509_get_serial(cert, &gc);

  if (!openvpn_snprintf(fn, sizeof(fn), "%s%c%s", crl_dir, OS_SPECIFIC_DIRSEP, serial))
    {
      msg (D_HANDSHAKE, "VERIFY CRL: filename overflow");
      goto cleanup;
    }
  fd = platform_open (fn, O_RDONLY, 0);
  if (fd >= 0)
    {
      msg (D_HANDSHAKE, "VERIFY CRL: certificate serial number %s is revoked", serial);
      goto cleanup;
    }

  ret = SUCCESS;

cleanup:

  if (fd != -1)
    close(fd);
  gc_free(&gc);
  return ret;
}

result_t
verify_cert(struct tls_session *session, openvpn_x509_cert_t *cert, int cert_depth)
{
  result_t ret = FAILURE;
  char *subject = NULL;
  char common_name[TLS_USERNAME_LEN] = {0};
  const struct tls_options *opt;
  struct gc_arena gc = gc_new();

  opt = session->opt;
  ASSERT (opt);

  session->verified = false;

  /* get the X509 name */
  subject = x509_get_subject(cert, &gc);
  if (!subject)
    {
	msg (D_TLS_ERRORS, "VERIFY ERROR: depth=%d, could not extract X509 "
	    "subject string from certificate", cert_depth);
	goto cleanup;
    }

  /* enforce character class restrictions in X509 name */
  string_mod_remap_name (subject, X509_NAME_CHAR_CLASS);
  string_replace_leading (subject, '-', '_');

  /* extract the username (default is CN) */
  if (SUCCESS != x509_get_username (common_name, TLS_USERNAME_LEN,
      opt->x509_username_field, cert))
    {
      if (!cert_depth)
	{
	  msg (D_TLS_ERRORS, "VERIFY ERROR: could not extract %s from X509 "
	      "subject string ('%s') -- note that the username length is "
	      "limited to %d characters",
	       opt->x509_username_field,
		 subject,
		 TLS_USERNAME_LEN);
	  goto cleanup;
	}
    }

  /* enforce character class restrictions in common name */
  string_mod_remap_name (common_name, COMMON_NAME_CHAR_CLASS);

  /* warn if cert chain is too deep */
  if (cert_depth >= MAX_CERT_DEPTH)
    {
      msg (D_TLS_ERRORS, "TLS Error: Convoluted certificate chain detected with depth [%d] greater than %d", cert_depth, MAX_CERT_DEPTH);
      goto cleanup;			/* Reject connection */
    }

  /* verify level 1 cert, i.e. the CA that signed our leaf cert */
  if (cert_depth == 1 && opt->verify_hash)
    {
      unsigned char *sha1_hash = x509_get_sha1_hash(cert, &gc);
      if (memcmp (sha1_hash, opt->verify_hash, SHA_DIGEST_LENGTH))
      {
	msg (D_TLS_ERRORS, "TLS Error: level-1 certificate hash verification failed");
	goto cleanup;
      }
    }

  /* save common name in session object */
  if (cert_depth == 0)
    set_common_name (session, common_name);

  session->verify_maxlevel = max_int (session->verify_maxlevel, cert_depth);

  /* export certificate values to the environment */
  verify_cert_set_env(opt->es, cert, cert_depth, subject, common_name
#ifdef ENABLE_X509_TRACK
      , opt->x509_track
#endif
      );

  /* export current untrusted IP */
  setenv_untrusted (session);

  /* If this is the peer's own certificate, verify it */
  if (cert_depth == 0 && SUCCESS != verify_peer_cert(opt, cert, subject, common_name))
    goto cleanup;

  /* call --tls-verify plug-in(s), if registered */
  if (SUCCESS != verify_cert_call_plugin(opt->plugins, opt->es, cert_depth, cert, subject))
    goto cleanup;

  /* run --tls-verify script */
  if (opt->verify_command && SUCCESS != verify_cert_call_command(opt->verify_command,
      opt->es, cert_depth, cert, subject, opt->verify_export_cert))
    goto cleanup;

  /* check peer cert against CRL */
  if (opt->crl_file)
    {
      if (opt->ssl_flags & SSLF_CRL_VERIFY_DIR)
      {
	if (SUCCESS != verify_check_crl_dir(opt->crl_file, cert))
	  goto cleanup;
      }
      else
      {
	if (SUCCESS != x509_verify_crl(opt->crl_file, cert, subject))
	  goto cleanup;
      }
    }

  msg (D_HANDSHAKE, "VERIFY OK: depth=%d, %s", cert_depth, subject);
  session->verified = true;
  ret = SUCCESS;

cleanup:

  if (ret != SUCCESS)
    {
      tls_clear_error(); /* always? */
      session->verified = false; /* double sure? */
    }
  gc_free(&gc);

  return ret;
}

/* ***************************************************************************
 * Functions for the management of deferred authentication when using
 * user/password authentication.
 *************************************************************************** */

#ifdef ENABLE_DEF_AUTH
/* key_state_test_auth_control_file return values,
   NOTE: acf_merge indexing depends on these values */
#define ACF_UNDEFINED 0
#define ACF_SUCCEEDED 1
#define ACF_DISABLED  2
#define ACF_FAILED    3
#endif

#ifdef MANAGEMENT_DEF_AUTH
void
man_def_auth_set_client_reason (struct tls_multi *multi, const char *client_reason)
{
  if (multi->client_reason)
    {
      free (multi->client_reason);
      multi->client_reason = NULL;
    }
  if (client_reason && strlen (client_reason))
    /* FIXME: Last alloc will never be freed */
    multi->client_reason = string_alloc (client_reason, NULL);
}

static inline unsigned int
man_def_auth_test (const struct key_state *ks)
{
  if (management_enable_def_auth (management))
    return ks->mda_status;
  else
    return ACF_DISABLED;
}
#endif

#ifdef PLUGIN_DEF_AUTH

/*
 * auth_control_file functions
 */

void
key_state_rm_auth_control_file (struct key_state *ks)
{
  if (ks && ks->auth_control_file)
    {
      platform_unlink (ks->auth_control_file);
      free (ks->auth_control_file);
      ks->auth_control_file = NULL;
    }
}

static void
key_state_gen_auth_control_file (struct key_state *ks, const struct tls_options *opt)
{
  struct gc_arena gc = gc_new ();
  const char *acf;

  key_state_rm_auth_control_file (ks);
  acf = create_temp_file (opt->tmp_dir, "acf", &gc);
  if (acf) {
    ks->auth_control_file = string_alloc (acf, NULL);
    setenv_str (opt->es, "auth_control_file", ks->auth_control_file);
  } /* FIXME: Should have better error handling? */

  gc_free (&gc);
}

static unsigned int
key_state_test_auth_control_file (struct key_state *ks)
{
  if (ks && ks->auth_control_file)
    {
      unsigned int ret = ks->auth_control_status;
      if (ret == ACF_UNDEFINED)
	{
	  FILE *fp = fopen (ks->auth_control_file, "r");
	  if (fp)
	    {
	      const int c = fgetc (fp);
	      if (c == '1')
		ret = ACF_SUCCEEDED;
	      else if (c == '0')
		ret = ACF_FAILED;
	      fclose (fp);
	      ks->auth_control_status = ret;
	    }
	}
      return ret;
    }
  return ACF_DISABLED;
}

#endif

/*
 * Return current session authentication state.  Return
 * value is TLS_AUTHENTICATION_x.
 */

int
tls_authentication_status (struct tls_multi *multi, const int latency)
{
  bool deferred = false;
  bool success = false;
  bool active = false;

#ifdef ENABLE_DEF_AUTH
  static const unsigned char acf_merge[] =
    {
      ACF_UNDEFINED, /* s1=ACF_UNDEFINED s2=ACF_UNDEFINED */
      ACF_UNDEFINED, /* s1=ACF_UNDEFINED s2=ACF_SUCCEEDED */
      ACF_UNDEFINED, /* s1=ACF_UNDEFINED s2=ACF_DISABLED */
      ACF_FAILED,    /* s1=ACF_UNDEFINED s2=ACF_FAILED */
      ACF_UNDEFINED, /* s1=ACF_SUCCEEDED s2=ACF_UNDEFINED */
      ACF_SUCCEEDED, /* s1=ACF_SUCCEEDED s2=ACF_SUCCEEDED */
      ACF_SUCCEEDED, /* s1=ACF_SUCCEEDED s2=ACF_DISABLED */
      ACF_FAILED,    /* s1=ACF_SUCCEEDED s2=ACF_FAILED */
      ACF_UNDEFINED, /* s1=ACF_DISABLED  s2=ACF_UNDEFINED */
      ACF_SUCCEEDED, /* s1=ACF_DISABLED  s2=ACF_SUCCEEDED */
      ACF_DISABLED,  /* s1=ACF_DISABLED  s2=ACF_DISABLED */
      ACF_FAILED,    /* s1=ACF_DISABLED  s2=ACF_FAILED */
      ACF_FAILED,    /* s1=ACF_FAILED    s2=ACF_UNDEFINED */
      ACF_FAILED,    /* s1=ACF_FAILED    s2=ACF_SUCCEEDED */
      ACF_FAILED,    /* s1=ACF_FAILED    s2=ACF_DISABLED */
      ACF_FAILED     /* s1=ACF_FAILED    s2=ACF_FAILED */
    };
#endif /* ENABLE_DEF_AUTH */

  if (multi)
    {
      int i;

#ifdef ENABLE_DEF_AUTH
      if (latency && multi->tas_last && multi->tas_last + latency >= now)
	return TLS_AUTHENTICATION_UNDEFINED;
      multi->tas_last = now;
#endif /* ENABLE_DEF_AUTH */

      for (i = 0; i < KEY_SCAN_SIZE; ++i)
	{
	  struct key_state *ks = multi->key_scan[i];
	  if (DECRYPT_KEY_ENABLED (multi, ks))
	    {
	      active = true;
	      if (ks->authenticated)
		{
#ifdef ENABLE_DEF_AUTH
		  unsigned int s1 = ACF_DISABLED;
		  unsigned int s2 = ACF_DISABLED;
#ifdef PLUGIN_DEF_AUTH
		  s1 = key_state_test_auth_control_file (ks);
#endif /* PLUGIN_DEF_AUTH */
#ifdef MANAGEMENT_DEF_AUTH
		  s2 = man_def_auth_test (ks);
#endif /* MANAGEMENT_DEF_AUTH */
		  ASSERT (s1 < 4 && s2 < 4);
		  switch (acf_merge[(s1<<2) + s2])
		    {
		    case ACF_SUCCEEDED:
		    case ACF_DISABLED:
		      success = true;
		      ks->auth_deferred = false;
		      break;
		    case ACF_UNDEFINED:
		      if (now < ks->auth_deferred_expire)
			deferred = true;
		      break;
		    case ACF_FAILED:
		      ks->authenticated = false;
		      break;
		    default:
		      ASSERT (0);
		    }
#else /* !ENABLE_DEF_AUTH */
		  success = true;
#endif /* ENABLE_DEF_AUTH */
		}
	    }
	}
    }

#if 0
  dmsg (D_TLS_ERRORS, "TAS: a=%d s=%d d=%d", active, success, deferred);
#endif

  if (success)
    return TLS_AUTHENTICATION_SUCCEEDED;
  else if (!active || deferred)
    return TLS_AUTHENTICATION_DEFERRED;
  else
    return TLS_AUTHENTICATION_FAILED;
}

#ifdef MANAGEMENT_DEF_AUTH
/*
 * For deferred auth, this is where the management interface calls (on server)
 * to indicate auth failure/success.
 */
bool
tls_authenticate_key (struct tls_multi *multi, const unsigned int mda_key_id, const bool auth, const char *client_reason)
{
  bool ret = false;
  if (multi)
    {
      int i;
      man_def_auth_set_client_reason (multi, client_reason);
      for (i = 0; i < KEY_SCAN_SIZE; ++i)
	{
	  struct key_state *ks = multi->key_scan[i];
	  if (ks->mda_key_id == mda_key_id)
	    {
	      ks->mda_status = auth ? ACF_SUCCEEDED : ACF_FAILED;
	      ret = true;
	    }
	}
    }
  return ret;
}
#endif


/* ****************************************************************************
 * Functions to verify username and password
 *
 * Authenticate a client using username/password.
 * Runs on server.
 *
 * If you want to add new authentication methods,
 * this is the place to start.
 *************************************************************************** */

/*
 * Verify the user name and password using a script
 */
static bool
verify_user_pass_script (struct tls_session *session, const struct user_pass *up)
{
  struct gc_arena gc = gc_new ();
  struct argv argv = argv_new ();
  const char *tmp_file = "";
  bool ret = false;

  /* Is username defined? */
  if ((session->opt->ssl_flags & SSLF_AUTH_USER_PASS_OPTIONAL) || strlen (up->username))
    {
      /* Set environmental variables prior to calling script */
      setenv_str (session->opt->es, "script_type", "user-pass-verify");

      if (session->opt->auth_user_pass_verify_script_via_file)
	{
	  struct status_output *so;

	  tmp_file = create_temp_file (session->opt->tmp_dir, "up", &gc);
          if( tmp_file ) {
	    so = status_open (tmp_file, 0, -1, NULL, STATUS_OUTPUT_WRITE);
	    status_printf (so, "%s", up->username);
	    status_printf (so, "%s", up->password);
	    if (!status_close (so))
	      {
		msg (D_TLS_ERRORS, "TLS Auth Error: could not write username/password to file: %s",
		     tmp_file);
		goto done;
	      }
          } else {
            msg (D_TLS_ERRORS, "TLS Auth Error: could not create write "
                 "username/password to temp file");
          }
	}
      else
	{
	  setenv_str (session->opt->es, "username", up->username);
	  setenv_str (session->opt->es, "password", up->password);
	}

      /* setenv incoming cert common name for script */
      setenv_str (session->opt->es, "common_name", session->common_name);

      /* setenv client real IP address */
      setenv_untrusted (session);

      /* format command line */
      argv_printf (&argv, "%sc %s", session->opt->auth_user_pass_verify_script, tmp_file);

      /* call command */
      ret = openvpn_run_script (&argv, session->opt->es, 0,
				"--auth-user-pass-verify");

      if (!session->opt->auth_user_pass_verify_script_via_file)
	setenv_del (session->opt->es, "password");
    }
  else
    {
      msg (D_TLS_ERRORS, "TLS Auth Error: peer provided a blank username");
    }

 done:
  if (tmp_file && strlen (tmp_file) > 0)
    platform_unlink (tmp_file);

  argv_reset (&argv);
  gc_free (&gc);
  return ret;
}

/*
 * Verify the username and password using a plugin
 */
static int
verify_user_pass_plugin (struct tls_session *session, const struct user_pass *up, const char *raw_username)
{
  int retval = OPENVPN_PLUGIN_FUNC_ERROR;
  struct key_state *ks = &session->key[KS_PRIMARY]; 	   /* primary key */

  /* Is username defined? */
  if ((session->opt->ssl_flags & SSLF_AUTH_USER_PASS_OPTIONAL) || strlen (up->username))
    {
      /* set username/password in private env space */
      setenv_str (session->opt->es, "username", (raw_username ? raw_username : up->username));
      setenv_str (session->opt->es, "password", up->password);

      /* setenv incoming cert common name for script */
      setenv_str (session->opt->es, "common_name", session->common_name);

      /* setenv client real IP address */
      setenv_untrusted (session);

#ifdef PLUGIN_DEF_AUTH
      /* generate filename for deferred auth control file */
      key_state_gen_auth_control_file (ks, session->opt);
#endif

      /* call command */
      retval = plugin_call (session->opt->plugins, OPENVPN_PLUGIN_AUTH_USER_PASS_VERIFY, NULL, NULL, session->opt->es);

#ifdef PLUGIN_DEF_AUTH
      /* purge auth control filename (and file itself) for non-deferred returns */
      if (retval != OPENVPN_PLUGIN_FUNC_DEFERRED)
	key_state_rm_auth_control_file (ks);
#endif

      setenv_del (session->opt->es, "password");
      if (raw_username)
        setenv_str (session->opt->es, "username", up->username);
    }
  else
    {
      msg (D_TLS_ERRORS, "TLS Auth Error (verify_user_pass_plugin): peer provided a blank username");
    }

  return retval;
}


#ifdef MANAGEMENT_DEF_AUTH
/*
 * MANAGEMENT_DEF_AUTH internal ssl_verify.c status codes
 */
#define KMDA_ERROR   0
#define KMDA_SUCCESS 1
#define KMDA_UNDEF   2
#define KMDA_DEF     3

static int
verify_user_pass_management (struct tls_session *session, const struct user_pass *up, const char *raw_username)
{
  int retval = KMDA_ERROR;
  struct key_state *ks = &session->key[KS_PRIMARY]; 	   /* primary key */

  /* Is username defined? */
  if ((session->opt->ssl_flags & SSLF_AUTH_USER_PASS_OPTIONAL) || strlen (up->username))
    {
      /* set username/password in private env space */
      setenv_str (session->opt->es, "username", (raw_username ? raw_username : up->username));
      setenv_str (session->opt->es, "password", up->password);

      /* setenv incoming cert common name for script */
      setenv_str (session->opt->es, "common_name", session->common_name);

      /* setenv client real IP address */
      setenv_untrusted (session);

      if (management)
	management_notify_client_needing_auth (management, ks->mda_key_id, session->opt->mda_context, session->opt->es);

      setenv_del (session->opt->es, "password");
      if (raw_username)
        setenv_str (session->opt->es, "username", up->username);

      retval = KMDA_SUCCESS;
    }
  else
    {
      msg (D_TLS_ERRORS, "TLS Auth Error (verify_user_pass_management): peer provided a blank username");
    }

  return retval;
}
#endif

/*
 * Main username/password verification entry point
 */
void
verify_user_pass(struct user_pass *up, struct tls_multi *multi,
    struct tls_session *session)
{
  int s1 = OPENVPN_PLUGIN_FUNC_SUCCESS;
  bool s2 = true;
  struct key_state *ks = &session->key[KS_PRIMARY]; 	   /* primary key */

  struct gc_arena gc = gc_new ();
  char *raw_username = NULL;

#ifdef MANAGEMENT_DEF_AUTH
  int man_def_auth = KMDA_UNDEF;

  if (management_enable_def_auth (management))
    man_def_auth = KMDA_DEF;
#endif

  /*
   * Preserve the raw username before string_mod remapping, for plugins
   * and management clients when in --compat-names mode
   */
  if (compat_flag (COMPAT_FLAG_QUERY | COMPAT_NAMES))
    {
      ALLOC_ARRAY_CLEAR_GC (raw_username, char, USER_PASS_LEN, &gc);
      strcpy (raw_username, up->username);
      string_mod (raw_username, CC_PRINT, CC_CRLF, '_');
    }

  /* enforce character class restrictions in username/password */
  string_mod_remap_name (up->username, COMMON_NAME_CHAR_CLASS);
  string_mod (up->password, CC_PRINT, CC_CRLF, '_');

  /* call plugin(s) and/or script */
#ifdef MANAGEMENT_DEF_AUTH
  if (man_def_auth == KMDA_DEF)
    man_def_auth = verify_user_pass_management (session, up, raw_username);
#endif
  if (plugin_defined (session->opt->plugins, OPENVPN_PLUGIN_AUTH_USER_PASS_VERIFY))
    s1 = verify_user_pass_plugin (session, up, raw_username);
  if (session->opt->auth_user_pass_verify_script)
    s2 = verify_user_pass_script (session, up);

  /* check sizing of username if it will become our common name */
  if ((session->opt->ssl_flags & SSLF_USERNAME_AS_COMMON_NAME) && strlen (up->username) >= TLS_USERNAME_LEN)
    {
      msg (D_TLS_ERRORS, "TLS Auth Error: --username-as-common name specified and username is longer than the maximum permitted Common Name length of %d characters", TLS_USERNAME_LEN);
      s1 = OPENVPN_PLUGIN_FUNC_ERROR;
    }

  /* auth succeeded? */
  if ((s1 == OPENVPN_PLUGIN_FUNC_SUCCESS
#ifdef PLUGIN_DEF_AUTH
       || s1 == OPENVPN_PLUGIN_FUNC_DEFERRED
#endif
       ) && s2
#ifdef MANAGEMENT_DEF_AUTH
       && man_def_auth != KMDA_ERROR
#endif
      && tls_lock_username (multi, up->username))
    {
      ks->authenticated = true;
#ifdef PLUGIN_DEF_AUTH
      if (s1 == OPENVPN_PLUGIN_FUNC_DEFERRED)
	ks->auth_deferred = true;
#endif
#ifdef MANAGEMENT_DEF_AUTH
      if (man_def_auth != KMDA_UNDEF)
	ks->auth_deferred = true;
#endif
      if ((session->opt->ssl_flags & SSLF_USERNAME_AS_COMMON_NAME))
	set_common_name (session, up->username);
#ifdef ENABLE_DEF_AUTH
      msg (D_HANDSHAKE, "TLS: Username/Password authentication %s for username '%s' %s",
	   ks->auth_deferred ? "deferred" : "succeeded",
	   up->username,
	   (session->opt->ssl_flags & SSLF_USERNAME_AS_COMMON_NAME) ? "[CN SET]" : "");
#else
      msg (D_HANDSHAKE, "TLS: Username/Password authentication %s for username '%s' %s",
	   "succeeded",
	   up->username,
	   (session->opt->ssl_flags & SSLF_USERNAME_AS_COMMON_NAME) ? "[CN SET]" : "");
#endif
    }
  else
    {
      msg (D_TLS_ERRORS, "TLS Auth Error: Auth Username/Password verification failed for peer");
    }

  gc_free (&gc);
}

void
verify_final_auth_checks(struct tls_multi *multi, struct tls_session *session)
{
  struct key_state *ks = &session->key[KS_PRIMARY]; 	   /* primary key */

  /* While it shouldn't really happen, don't allow the common name to be NULL */
  if (!session->common_name)
    set_common_name (session, "");

  /* Don't allow the CN to change once it's been locked */
  if (ks->authenticated && multi->locked_cn)
    {
      const char *cn = session->common_name;
      if (cn && strcmp (cn, multi->locked_cn))
	{
	  msg (D_TLS_ERRORS, "TLS Auth Error: TLS object CN attempted to change from '%s' to '%s' -- tunnel disabled",
	       multi->locked_cn,
	       cn);

	  /* change the common name back to its original value and disable the tunnel */
	  set_common_name (session, multi->locked_cn);
	  tls_deauthenticate (multi);
	}
    }

  /* Don't allow the cert hashes to change once they have been locked */
  if (ks->authenticated && multi->locked_cert_hash_set)
    {
      const struct cert_hash_set *chs = session->cert_hash_set;
      if (chs && !cert_hash_compare (chs, multi->locked_cert_hash_set))
	{
	  msg (D_TLS_ERRORS, "TLS Auth Error: TLS object CN=%s client-provided SSL certs unexpectedly changed during mid-session reauth",
	       session->common_name);

	  /* disable the tunnel */
	  tls_deauthenticate (multi);
	}
    }

  /* verify --client-config-dir based authentication */
  if (ks->authenticated && session->opt->client_config_dir_exclusive)
    {
      struct gc_arena gc = gc_new ();

      const char *cn = session->common_name;
      const char *path = gen_path (session->opt->client_config_dir_exclusive, cn, &gc);
      if (!cn || !strcmp (cn, CCD_DEFAULT) || !test_file (path))
	{
	  ks->authenticated = false;
	  msg (D_TLS_ERRORS, "TLS Auth Error: --client-config-dir authentication failed for common name '%s' file='%s'",
	       session->common_name,
	       path ? path : "UNDEF");
	}

      gc_free (&gc);
    }
}
#endif /* defined(ENABLE_CRYPTO) && defined(ENABLE_SSL) */