summaryrefslogtreecommitdiffstats
path: root/ssl_openssl.c
blob: 093ccf3a9a72faa2ee0602a0c25318a79336bd52 (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
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
/*
 *  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 OpenSSL Backend
 */

#include "syshead.h"
#include "errlevel.h"
#include "buffer.h"
#include "misc.h"
#include "manage.h"
#include "memdbg.h"
#include "ssl_backend.h"
#include "ssl_common.h"

#include "ssl_verify_openssl.h"

#include <openssl/err.h>
#include <openssl/pkcs12.h>
#include <openssl/x509.h>
#include <openssl/crypto.h>

/*
 * Allocate space in SSL objects in which to store a struct tls_session
 * pointer back to parent.
 *
 */

int mydata_index; /* GLOBAL */

void
tls_init_lib()
{
  SSL_library_init();
  SSL_load_error_strings();
  OpenSSL_add_all_algorithms ();

  mydata_index = SSL_get_ex_new_index(0, "struct session *", NULL, NULL, NULL);
  ASSERT (mydata_index >= 0);
}

void
tls_free_lib()
{
  EVP_cleanup();
  ERR_free_strings();
}

void
tls_clear_error()
{
  ERR_clear_error ();
}

/*
 * OpenSSL callback to get a temporary RSA key, mostly
 * used for export ciphers.
 */
static RSA *
tmp_rsa_cb (SSL * s, int is_export, int keylength)
{
  static RSA *rsa_tmp = NULL;
  if (rsa_tmp == NULL)
    {
      msg (D_HANDSHAKE, "Generating temp (%d bit) RSA key", keylength);
      rsa_tmp = RSA_generate_key (keylength, RSA_F4, NULL, NULL);
    }
  return (rsa_tmp);
}

void
tls_ctx_server_new(struct tls_root_ctx *ctx)
{
  ASSERT(NULL != ctx);

  ctx->ctx = SSL_CTX_new (TLSv1_server_method ());

  if (ctx->ctx == NULL)
    msg (M_SSLERR, "SSL_CTX_new TLSv1_server_method");

  SSL_CTX_set_tmp_rsa_callback (ctx->ctx, tmp_rsa_cb);
}

void
tls_ctx_client_new(struct tls_root_ctx *ctx)
{
  ASSERT(NULL != ctx);

  ctx->ctx = SSL_CTX_new (TLSv1_client_method ());

  if (ctx->ctx == NULL)
    msg (M_SSLERR, "SSL_CTX_new TLSv1_client_method");
}

void
tls_ctx_free(struct tls_root_ctx *ctx)
{
  ASSERT(NULL != ctx);
  if (NULL != ctx->ctx)
    SSL_CTX_free (ctx->ctx);
  ctx->ctx = NULL;
}

bool tls_ctx_initialised(struct tls_root_ctx *ctx)
{
  ASSERT(NULL != ctx);
  return NULL != ctx->ctx;
}

/*
 * Print debugging information on SSL/TLS session negotiation.
 */

#ifndef INFO_CALLBACK_SSL_CONST
#define INFO_CALLBACK_SSL_CONST const
#endif
static void
info_callback (INFO_CALLBACK_SSL_CONST SSL * s, int where, int ret)
{
  if (where & SSL_CB_LOOP)
    {
      dmsg (D_HANDSHAKE_VERBOSE, "SSL state (%s): %s",
	   where & SSL_ST_CONNECT ? "connect" :
	   where & SSL_ST_ACCEPT ? "accept" :
	   "undefined", SSL_state_string_long (s));
    }
  else if (where & SSL_CB_ALERT)
    {
      dmsg (D_HANDSHAKE_VERBOSE, "SSL alert (%s): %s: %s",
	   where & SSL_CB_READ ? "read" : "write",
	   SSL_alert_type_string_long (ret),
	   SSL_alert_desc_string_long (ret));
    }
}

void
tls_ctx_set_options (struct tls_root_ctx *ctx, unsigned int ssl_flags)
{
  ASSERT(NULL != ctx);

  SSL_CTX_set_session_cache_mode (ctx->ctx, SSL_SESS_CACHE_OFF);
  SSL_CTX_set_options (ctx->ctx, SSL_OP_SINGLE_DH_USE);
  SSL_CTX_set_default_passwd_cb (ctx->ctx, pem_password_callback);

  /* Require peer certificate verification */
#if P2MP_SERVER
  if (ssl_flags & SSLF_CLIENT_CERT_NOT_REQUIRED)
    {
      msg (M_WARN, "WARNING: POTENTIALLY DANGEROUS OPTION "
	  "--client-cert-not-required may accept clients which do not present "
	  "a certificate");
    }
  else
#endif
  SSL_CTX_set_verify (ctx->ctx, SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT,
		      verify_callback);

  SSL_CTX_set_info_callback (ctx->ctx, info_callback);
}

void
tls_ctx_restrict_ciphers(struct tls_root_ctx *ctx, const char *ciphers)
{
  ASSERT(NULL != ctx);

  if(!SSL_CTX_set_cipher_list(ctx->ctx, ciphers))
    msg(M_SSLERR, "Failed to set restricted TLS cipher list: %s", ciphers);
}

void
tls_ctx_load_dh_params (struct tls_root_ctx *ctx, const char *dh_file
#if ENABLE_INLINE_FILES
    , const char *dh_file_inline
#endif /* ENABLE_INLINE_FILES */
    )
{
  DH *dh;
  BIO *bio;

  ASSERT(NULL != ctx);

#if ENABLE_INLINE_FILES
  if (!strcmp (dh_file, INLINE_FILE_TAG) && dh_file_inline)
    {
      if (!(bio = BIO_new_mem_buf ((char *)dh_file_inline, -1)))
	msg (M_SSLERR, "Cannot open memory BIO for inline DH parameters");
    }
  else
#endif /* ENABLE_INLINE_FILES */
    {
      /* Get Diffie Hellman Parameters */
      if (!(bio = BIO_new_file (dh_file, "r")))
	msg (M_SSLERR, "Cannot open %s for DH parameters", dh_file);
    }

  dh = PEM_read_bio_DHparams (bio, NULL, NULL, NULL);
  BIO_free (bio);

  if (!dh)
    msg (M_SSLERR, "Cannot load DH parameters from %s", dh_file);
  if (!SSL_CTX_set_tmp_dh (ctx->ctx, dh))
    msg (M_SSLERR, "SSL_CTX_set_tmp_dh");

  msg (D_TLS_DEBUG_LOW, "Diffie-Hellman initialized with %d bit key",
       8 * DH_size (dh));

  DH_free (dh);
}

int
tls_ctx_load_pkcs12(struct tls_root_ctx *ctx, const char *pkcs12_file,
#if ENABLE_INLINE_FILES
    const char *pkcs12_file_inline,
#endif /* ENABLE_INLINE_FILES */
    bool load_ca_file
    )
{
  FILE *fp;
  EVP_PKEY *pkey;
  X509 *cert;
  STACK_OF(X509) *ca = NULL;
  PKCS12 *p12;
  int i;
  char password[256];

  ASSERT(NULL != ctx);

#if ENABLE_INLINE_FILES
  if (!strcmp (pkcs12_file, INLINE_FILE_TAG) && pkcs12_file_inline)
    {
      BIO *b64 = BIO_new(BIO_f_base64());
      BIO *bio = BIO_new_mem_buf((void *) pkcs12_file_inline,
	  (int) strlen(pkcs12_file_inline));
      ASSERT(b64 && bio);
      BIO_push(b64, bio);
      p12 = d2i_PKCS12_bio(b64, NULL);
      if (!p12)
	msg(M_SSLERR, "Error reading inline PKCS#12 file");
      BIO_free(b64);
      BIO_free(bio);
    }
  else
#endif
    {
      /* Load the PKCS #12 file */
      if (!(fp = fopen(pkcs12_file, "rb")))
	msg(M_SSLERR, "Error opening file %s", pkcs12_file);
      p12 = d2i_PKCS12_fp(fp, NULL);
      fclose(fp);
      if (!p12)
	msg(M_SSLERR, "Error reading PKCS#12 file %s", pkcs12_file);
    }

  /* Parse the PKCS #12 file */
  if (!PKCS12_parse(p12, "", &pkey, &cert, &ca))
   {
     pem_password_callback (password, sizeof(password) - 1, 0, NULL);
     /* Reparse the PKCS #12 file with password */
     ca = NULL;
     if (!PKCS12_parse(p12, password, &pkey, &cert, &ca))
      {
#ifdef ENABLE_MANAGEMENT
	      if (management && (ERR_GET_REASON (ERR_peek_error()) == PKCS12_R_MAC_VERIFY_FAILURE))
		management_auth_failure (management, UP_TYPE_PRIVATE_KEY, NULL);
#endif
	PKCS12_free(p12);
	return 1;
      }
   }
  PKCS12_free(p12);

  /* Load Certificate */
  if (!SSL_CTX_use_certificate (ctx->ctx, cert))
   msg (M_SSLERR, "Cannot use certificate");

  /* Load Private Key */
  if (!SSL_CTX_use_PrivateKey (ctx->ctx, pkey))
   msg (M_SSLERR, "Cannot use private key");
  warn_if_group_others_accessible (pkcs12_file);

  /* Check Private Key */
  if (!SSL_CTX_check_private_key (ctx->ctx))
   msg (M_SSLERR, "Private key does not match the certificate");

  /* Set Certificate Verification chain */
  if (load_ca_file)
   {
     if (ca && sk_X509_num(ca))
      {
	for (i = 0; i < sk_X509_num(ca); i++)
	  {
	      if (!X509_STORE_add_cert(ctx->ctx->cert_store,sk_X509_value(ca, i)))
	      msg (M_SSLERR, "Cannot add certificate to certificate chain (X509_STORE_add_cert)");
	    if (!SSL_CTX_add_client_CA(ctx->ctx, sk_X509_value(ca, i)))
	      msg (M_SSLERR, "Cannot add certificate to client CA list (SSL_CTX_add_client_CA)");
	  }
      }
   }
  return 0;
}

#ifdef ENABLE_CRYPTOAPI
void
tls_ctx_load_cryptoapi(struct tls_root_ctx *ctx, const char *cryptoapi_cert)
{
  ASSERT(NULL != ctx);

  /* Load Certificate and Private Key */
  if (!SSL_CTX_use_CryptoAPI_certificate (ctx->ctx, cryptoapi_cert))
    msg (M_SSLERR, "Cannot load certificate \"%s\" from Microsoft Certificate Store",
	   options->cryptoapi_cert);
}
#endif /* WIN32 */

/*
 * Based on SSL_CTX_use_certificate_file, return an x509 object for the
 * given file.
 */
static int
tls_ctx_read_certificate_file(SSL_CTX *ctx, const char *file, X509 **x509)
{
  int j;
  BIO *in;
  int ret=0;
  X509 *x=NULL;

  in=BIO_new(BIO_s_file_internal());
  if (in == NULL)
    {
      SSLerr(SSL_F_SSL_CTX_USE_CERTIFICATE_FILE, ERR_R_BUF_LIB);
      goto end;
    }

  if (BIO_read_filename(in,file) <= 0)
    {
      SSLerr(SSL_F_SSL_CTX_USE_CERTIFICATE_FILE, ERR_R_SYS_LIB);
      goto end;
    }

  x = PEM_read_bio_X509(in, NULL, ctx->default_passwd_callback,
    ctx->default_passwd_callback_userdata);
  if (x == NULL)
    {
      SSLerr(SSL_F_SSL_CTX_USE_CERTIFICATE_FILE, ERR_R_PEM_LIB);
      goto end;
    }

 end:
  if (in != NULL)
    BIO_free(in);
  if (x509)
    *x509 = x;
  else if (x)
    X509_free (x);
  return(ret);
}

void
tls_ctx_load_cert_file (struct tls_root_ctx *ctx, const char *cert_file,
#if ENABLE_INLINE_FILES
    const char *cert_file_inline,
#endif
    X509 **x509
    )
{
  ASSERT(NULL != ctx);
  if (NULL != x509)
    ASSERT(NULL == *x509);

#if ENABLE_INLINE_FILES
  if (!strcmp (cert_file, INLINE_FILE_TAG) && cert_file_inline)
    {
      BIO *in = NULL;
      X509 *x = NULL;
      int ret = 0;

      in = BIO_new_mem_buf ((char *)cert_file_inline, -1);
      if (in)
	{
	  x = PEM_read_bio_X509 (in,
			     NULL,
			     ctx->ctx->default_passwd_callback,
			     ctx->ctx->default_passwd_callback_userdata);
	  BIO_free (in);
	  if (x) {
	    ret = SSL_CTX_use_certificate(ctx->ctx, x);
	    if (x509)
	      *x509 = x;
	    else
	      X509_free (x);
	  }
	}

      if (!ret)
        msg (M_SSLERR, "Cannot load inline certificate file");
    }
  else
#endif /* ENABLE_INLINE_FILES */
    {
      if (!SSL_CTX_use_certificate_chain_file (ctx->ctx, cert_file))
	msg (M_SSLERR, "Cannot load certificate file %s", cert_file);
      if (x509)
	{
	  if (!tls_ctx_read_certificate_file(ctx->ctx, cert_file, x509))
	    msg (M_SSLERR, "Cannot load certificate file %s", cert_file);
	}
    }
}

void
tls_ctx_free_cert_file (X509 *x509)
{
  X509_free(x509);
}

#if ENABLE_INLINE_FILES
static int
use_inline_PrivateKey_file (SSL_CTX *ctx, const char *key_string)
{
  BIO *in = NULL;
  EVP_PKEY *pkey = NULL;
  int ret = 0;

  in = BIO_new_mem_buf ((char *)key_string, -1);
  if (!in)
    goto end;

  pkey = PEM_read_bio_PrivateKey (in,
				  NULL,
				  ctx->default_passwd_callback,
				  ctx->default_passwd_callback_userdata);
  if (!pkey)
    goto end;

  ret = SSL_CTX_use_PrivateKey (ctx, pkey);

 end:
  if (pkey)
    EVP_PKEY_free (pkey);
  if (in)
    BIO_free (in);
  return ret;
}
#endif /* ENABLE_INLINE_FILES */

int
tls_ctx_load_priv_file (struct tls_root_ctx *ctx, const char *priv_key_file
#if ENABLE_INLINE_FILES
    , const char *priv_key_file_inline
#endif
    )
{
  ASSERT(NULL != ctx);

  int status;

#if ENABLE_INLINE_FILES
  if (!strcmp (priv_key_file, INLINE_FILE_TAG) && priv_key_file_inline)
    {
      status = use_inline_PrivateKey_file (ctx->ctx, priv_key_file_inline);
    }
  else
#endif /* ENABLE_INLINE_FILES */
    {
      status = SSL_CTX_use_PrivateKey_file (ctx->ctx, priv_key_file, SSL_FILETYPE_PEM);
    }
  if (!status)
    {
#ifdef ENABLE_MANAGEMENT
      if (management && (ERR_GET_REASON (ERR_peek_error()) == EVP_R_BAD_DECRYPT))
	  management_auth_failure (management, UP_TYPE_PRIVATE_KEY, NULL);
#endif
      msg (M_WARN|M_SSL, "Cannot load private key file %s", priv_key_file);
      return 1;
    }
  warn_if_group_others_accessible (priv_key_file);

  /* Check Private Key */
  if (!SSL_CTX_check_private_key (ctx->ctx))
    msg (M_SSLERR, "Private key does not match the certificate");
  return 0;

}

#ifdef MANAGMENT_EXTERNAL_KEY

/* encrypt */
static int
rsa_pub_enc(int flen, const unsigned char *from, unsigned char *to, RSA *rsa, int padding)
{
  ASSERT(0);
  return -1;
}

/* verify arbitrary data */
static int
rsa_pub_dec(int flen, const unsigned char *from, unsigned char *to, RSA *rsa, int padding)
{
  ASSERT(0);
  return -1;
}

/* decrypt */
static int
rsa_priv_dec(int flen, const unsigned char *from, unsigned char *to, RSA *rsa, int padding)
{
  ASSERT(0);
  return -1;
}

/* called at RSA_free */
static int
rsa_finish(RSA *rsa)
{
  free ((void*)rsa->meth);
  rsa->meth = NULL;
  return 1;
}

/* sign arbitrary data */
static int
rsa_priv_enc(int flen, const unsigned char *from, unsigned char *to, RSA *rsa, int padding)
{
  /* optional app data in rsa->meth->app_data; */
  char *in_b64 = NULL;
  char *out_b64 = NULL;
  int ret = -1;
  int len;

  if (padding != RSA_PKCS1_PADDING)
    {
      RSAerr (RSA_F_RSA_EAY_PRIVATE_ENCRYPT, RSA_R_UNKNOWN_PADDING_TYPE);
      goto done;
    }

  /* convert 'from' to base64 */
  if (openvpn_base64_encode (from, flen, &in_b64) <= 0)
    goto done;

  /* call MI for signature */
  if (management)
    out_b64 = management_query_rsa_sig (management, in_b64);
  if (!out_b64)
    goto done;

  /* decode base64 signature to binary */
  len = RSA_size(rsa);
  ret = openvpn_base64_decode (out_b64, to, len);

  /* verify length */
  if (ret != len)
    ret = -1;

 done:
  if (in_b64)
    free (in_b64);
  if (out_b64)
    free (out_b64);
  return ret;
}

int
tls_ctx_use_external_private_key (struct tls_root_ctx *ctx, X509 *cert)
{
  RSA *rsa = NULL;
  RSA *pub_rsa;
  RSA_METHOD *rsa_meth;

  ASSERT (NULL != ctx);
  ASSERT (NULL != cert);

  /* allocate custom RSA method object */
  ALLOC_OBJ_CLEAR (rsa_meth, RSA_METHOD);
  rsa_meth->name = "OpenVPN external private key RSA Method";
  rsa_meth->rsa_pub_enc = rsa_pub_enc;
  rsa_meth->rsa_pub_dec = rsa_pub_dec;
  rsa_meth->rsa_priv_enc = rsa_priv_enc;
  rsa_meth->rsa_priv_dec = rsa_priv_dec;
  rsa_meth->init = NULL;
  rsa_meth->finish = rsa_finish;
  rsa_meth->flags = RSA_METHOD_FLAG_NO_CHECK;
  rsa_meth->app_data = NULL;

  /* allocate RSA object */
  rsa = RSA_new();
  if (rsa == NULL)
    {
      SSLerr(SSL_F_SSL_USE_PRIVATEKEY, ERR_R_MALLOC_FAILURE);
      goto err;
    }

  /* get the public key */
  ASSERT(cert->cert_info->key->pkey); /* NULL before SSL_CTX_use_certificate() is called */
  pub_rsa = cert->cert_info->key->pkey->pkey.rsa;

  /* initialize RSA object */
  rsa->n = BN_dup(pub_rsa->n);
  rsa->flags |= RSA_FLAG_EXT_PKEY;
  if (!RSA_set_method(rsa, rsa_meth))
    goto err;

  /* bind our custom RSA object to ssl_ctx */
  if (!SSL_CTX_use_RSAPrivateKey(ctx->ctx, rsa))
    goto err;

  RSA_free(rsa); /* doesn't necessarily free, just decrements refcount */
  return 1;

 err:
  if (rsa)
    RSA_free(rsa);
  else
    {
      if (rsa_meth)
	free(rsa_meth);
    }
  msg (M_SSLERR, "Cannot enable SSL external private key capability");
  return 0;
}

#endif

#if ENABLE_INLINE_FILES
static int
xname_cmp(const X509_NAME * const *a, const X509_NAME * const *b)
{
  return(X509_NAME_cmp(*a,*b));
}

static STACK_OF(X509_NAME) *
use_inline_load_client_CA_file (SSL_CTX *ctx, const char *ca_string)
{
  BIO *in = NULL;
  X509 *x = NULL;
  X509_NAME *xn = NULL;
  STACK_OF(X509_NAME) *ret = NULL, *sk;

  sk=sk_X509_NAME_new(xname_cmp);

  in = BIO_new_mem_buf ((char *)ca_string, -1);
  if (!in)
    goto err;

  if ((sk == NULL) || (in == NULL))
    goto err;

  for (;;)
    {
      if (PEM_read_bio_X509(in,&x,NULL,NULL) == NULL)
	break;
      if (ret == NULL)
	{
	  ret = sk_X509_NAME_new_null();
	  if (ret == NULL)
	    goto err;
	}
      if ((xn=X509_get_subject_name(x)) == NULL) goto err;
      /* check for duplicates */
      xn=X509_NAME_dup(xn);
      if (xn == NULL) goto err;
      if (sk_X509_NAME_find(sk,xn) >= 0)
	X509_NAME_free(xn);
      else
	{
	  sk_X509_NAME_push(sk,xn);
	  sk_X509_NAME_push(ret,xn);
	}
    }

  if (0)
    {
    err:
      if (ret != NULL) sk_X509_NAME_pop_free(ret,X509_NAME_free);
      ret=NULL;
    }
  if (sk != NULL) sk_X509_NAME_free(sk);
  if (in != NULL) BIO_free(in);
  if (x != NULL) X509_free(x);
  if (ret != NULL)
    ERR_clear_error();
  return(ret);
}

static int
use_inline_load_verify_locations (SSL_CTX *ctx, const char *ca_string)
{
  X509_STORE *store = NULL;
  X509* cert = NULL;
  BIO *in = NULL;
  int ret = 0;

  in = BIO_new_mem_buf ((char *)ca_string, -1);
  if (!in)
    goto err;

  for (;;)
    {
      if (!PEM_read_bio_X509 (in, &cert, 0, NULL))
	{
	  ret = 1;
	  break;
	}
      if (!cert)
	break;

      store = SSL_CTX_get_cert_store (ctx);
      if (!store)
	break;

      if (!X509_STORE_add_cert (store, cert))
	break;

      if (cert)
	{
	  X509_free (cert);
	  cert = NULL;
	}
    }

 err:
  if (cert)
    X509_free (cert);
  if (in)
    BIO_free (in);
  return ret;
}
#endif /* ENABLE_INLINE_FILES */

void
tls_ctx_load_ca (struct tls_root_ctx *ctx, const char *ca_file,
#if ENABLE_INLINE_FILES
    const char *ca_file_inline,
#endif
    const char *ca_path, bool tls_server
    )
{
  int status;

  ASSERT(NULL != ctx);

#if ENABLE_INLINE_FILES
  if (ca_file && !strcmp (ca_file, INLINE_FILE_TAG) && ca_file_inline)
	{
	  status = use_inline_load_verify_locations (ctx->ctx, ca_file_inline);
	}
  else
#endif
	{
	  /* Load CA file for verifying peer supplied certificate */
	  status = SSL_CTX_load_verify_locations (ctx->ctx, ca_file, ca_path);
	}

  if (!status)
	msg (M_SSLERR, "Cannot load CA certificate file %s path %s (SSL_CTX_load_verify_locations)", np(ca_file), np(ca_path));

  /* Set a store for certs (CA & CRL) with a lookup on the "capath" hash directory */
  if (ca_path) {
    X509_STORE *store = SSL_CTX_get_cert_store(ctx->ctx);

    if (store)
	  {
	    X509_LOOKUP *lookup = X509_STORE_add_lookup(store, X509_LOOKUP_hash_dir());
	    if (!X509_LOOKUP_add_dir(lookup, ca_path, X509_FILETYPE_PEM))
	      X509_LOOKUP_add_dir(lookup, NULL, X509_FILETYPE_DEFAULT);
	    else
	      msg(M_WARN, "WARNING: experimental option --capath %s", ca_path);
#if OPENSSL_VERSION_NUMBER >= 0x00907000L
	    X509_STORE_set_flags(store, X509_V_FLAG_CRL_CHECK | X509_V_FLAG_CRL_CHECK_ALL);
#else
	    msg(M_WARN, "WARNING: this version of OpenSSL cannot handle CRL files in capath");
#endif
	  }
	else
      msg(M_SSLERR, "Cannot get certificate store (SSL_CTX_get_cert_store)");
  }

  /* Load names of CAs from file and use it as a client CA list */
  if (ca_file && tls_server) {
    STACK_OF(X509_NAME) *cert_names = NULL;
#if ENABLE_INLINE_FILES
	if (!strcmp (ca_file, INLINE_FILE_TAG) && ca_file_inline)
	  {
	    cert_names = use_inline_load_client_CA_file (ctx->ctx, ca_file_inline);
	  }
	else
#endif
	  {
	    cert_names = SSL_load_client_CA_file (ca_file);
	  }
    if (!cert_names)
      msg (M_SSLERR, "Cannot load CA certificate file %s (SSL_load_client_CA_file)", ca_file);
    SSL_CTX_set_client_CA_list (ctx->ctx, cert_names);
  }
}


void
tls_ctx_load_extra_certs (struct tls_root_ctx *ctx, const char *extra_certs_file
#if ENABLE_INLINE_FILES
    , const char *extra_certs_file_inline
#endif
    )
{
  BIO *bio;
  X509 *cert;
#if ENABLE_INLINE_FILES
  if (!strcmp (extra_certs_file, INLINE_FILE_TAG) && extra_certs_file_inline)
    {
      bio = BIO_new_mem_buf ((char *)extra_certs_file_inline, -1);
    }
  else
#endif
    {
      bio = BIO_new(BIO_s_file());
      if (BIO_read_filename(bio, extra_certs_file) <= 0)
	msg (M_SSLERR, "Cannot load extra-certs file: %s", extra_certs_file);
    }
  for (;;)
    {
      cert = NULL;
      if (!PEM_read_bio_X509 (bio, &cert, 0, NULL)) /* takes ownership of cert */
	break;
      if (!cert)
	msg (M_SSLERR, "Error reading extra-certs certificate");
      if (SSL_CTX_add_extra_chain_cert(ctx->ctx, cert) != 1)
	msg (M_SSLERR, "Error adding extra-certs certificate");
    }
  BIO_free (bio);
}

/* **************************************
 *
 * Key-state specific functions
 *
 ***************************************/
/*
 *
 * BIO functions
 *
 */

#ifdef BIO_DEBUG

#warning BIO_DEBUG defined

static FILE *biofp;                            /* GLOBAL */
static bool biofp_toggle;                      /* GLOBAL */
static time_t biofp_last_open;                 /* GLOBAL */
static const int biofp_reopen_interval = 600;  /* GLOBAL */

static void
close_biofp()
{
  if (biofp)
    {
      ASSERT (!fclose (biofp));
      biofp = NULL;
    }
}

static void
open_biofp()
{
  const time_t current = time (NULL);
  const pid_t pid = getpid ();

  if (biofp_last_open + biofp_reopen_interval < current)
    close_biofp();
  if (!biofp)
    {
      char fn[256];
      openvpn_snprintf(fn, sizeof(fn), "bio/%d-%d.log", pid, biofp_toggle);
      biofp = fopen (fn, "w");
      ASSERT (biofp);
      biofp_last_open = time (NULL);
      biofp_toggle ^= 1;
    }
}

static void
bio_debug_data (const char *mode, BIO *bio, const uint8_t *buf, int len, const char *desc)
{
  struct gc_arena gc = gc_new ();
  if (len > 0)
    {
      open_biofp();
      fprintf(biofp, "BIO_%s %s time=" time_format " bio=" ptr_format " len=%d data=%s\n",
	      mode, desc, time (NULL), (ptr_type)bio, len, format_hex (buf, len, 0, &gc));
      fflush (biofp);
    }
  gc_free (&gc);
}

static void
bio_debug_oc (const char *mode, BIO *bio)
{
  open_biofp();
  fprintf(biofp, "BIO %s time=" time_format " bio=" ptr_format "\n",
	  mode, time (NULL), (ptr_type)bio);
  fflush (biofp);
}

#endif

/*
 * OpenVPN's interface to SSL/TLS authentication,
 * encryption, and decryption is exclusively
 * through "memory BIOs".
 */
static BIO *
getbio (BIO_METHOD * type, const char *desc)
{
  BIO *ret;
  ret = BIO_new (type);
  if (!ret)
    msg (M_SSLERR, "Error creating %s BIO", desc);
  return ret;
}

/*
 * Write to an OpenSSL BIO in non-blocking mode.
 */
static int
bio_write (BIO *bio, const uint8_t *data, int size, const char *desc)
{
  int i;
  int ret = 0;
  ASSERT (size >= 0);
  if (size)
    {
      /*
       * Free the L_TLS lock prior to calling BIO routines
       * so that foreground thread can still call
       * tls_pre_decrypt or tls_pre_encrypt,
       * allowing tunnel packet forwarding to continue.
       */
#ifdef BIO_DEBUG
      bio_debug_data ("write", bio, data, size, desc);
#endif
      i = BIO_write (bio, data, size);

      if (i < 0)
	{
	  if (BIO_should_retry (bio))
	    {
	      ;
	    }
	  else
	    {
	      msg (D_TLS_ERRORS | M_SSL, "TLS ERROR: BIO write %s error",
		   desc);
	      ret = -1;
	      ERR_clear_error ();
	    }
	}
      else if (i != size)
	{
	  msg (D_TLS_ERRORS | M_SSL,
	       "TLS ERROR: BIO write %s incomplete %d/%d", desc, i, size);
	  ret = -1;
	  ERR_clear_error ();
	}
      else
	{			/* successful write */
	  dmsg (D_HANDSHAKE_VERBOSE, "BIO write %s %d bytes", desc, i);
	  ret = 1;
	}
    }
  return ret;
}

/*
 * Inline functions for reading from and writing
 * to BIOs.
 */

static void
bio_write_post (const int status, struct buffer *buf)
{
  if (status == 1) /* success status return from bio_write? */
    {
      memset (BPTR (buf), 0, BLEN (buf)); /* erase data just written */
      buf->len = 0;
    }
}

/*
 * Read from an OpenSSL BIO in non-blocking mode.
 */
static int
bio_read (BIO *bio, struct buffer *buf, int maxlen, const char *desc)
{
  int i;
  int ret = 0;
  ASSERT (buf->len >= 0);
  if (buf->len)
    {
      ;
    }
  else
    {
      int len = buf_forward_capacity (buf);
      if (maxlen < len)
	len = maxlen;

      /*
       * BIO_read brackets most of the serious RSA
       * key negotiation number crunching.
       */
      i = BIO_read (bio, BPTR (buf), len);

      VALGRIND_MAKE_READABLE ((void *) &i, sizeof (i));

#ifdef BIO_DEBUG
      bio_debug_data ("read", bio, BPTR (buf), i, desc);
#endif
      if (i < 0)
	{
	  if (BIO_should_retry (bio))
	    {
	      ;
	    }
	  else
	    {
	      msg (D_TLS_ERRORS | M_SSL, "TLS_ERROR: BIO read %s error",
		   desc);
	      buf->len = 0;
	      ret = -1;
	      ERR_clear_error ();
	    }
	}
      else if (!i)
	{
	  buf->len = 0;
	}
      else
	{			/* successful read */
	  dmsg (D_HANDSHAKE_VERBOSE, "BIO read %s %d bytes", desc, i);
	  buf->len = i;
	  ret = 1;
	  VALGRIND_MAKE_READABLE ((void *) BPTR (buf), BLEN (buf));
	}
    }
  return ret;
}

void
key_state_ssl_init(struct key_state_ssl *ks_ssl, const struct tls_root_ctx *ssl_ctx, bool is_server, void *session)
{
  ASSERT(NULL != ssl_ctx);
  ASSERT(ks_ssl);
  CLEAR (*ks_ssl);

  ks_ssl->ssl = SSL_new (ssl_ctx->ctx);
  if (!ks_ssl->ssl)
    msg (M_SSLERR, "SSL_new failed");

  /* put session * in ssl object so we can access it
     from verify callback*/
  SSL_set_ex_data (ks_ssl->ssl, mydata_index, session);

  ks_ssl->ssl_bio = getbio (BIO_f_ssl (), "ssl_bio");
  ks_ssl->ct_in = getbio (BIO_s_mem (), "ct_in");
  ks_ssl->ct_out = getbio (BIO_s_mem (), "ct_out");

#ifdef BIO_DEBUG
  bio_debug_oc ("open ssl_bio", ks_ssl->ssl_bio);
  bio_debug_oc ("open ct_in", ks_ssl->ct_in);
  bio_debug_oc ("open ct_out", ks_ssl->ct_out);
#endif

  if (is_server)
    SSL_set_accept_state (ks_ssl->ssl);
  else
    SSL_set_connect_state (ks_ssl->ssl);

  SSL_set_bio (ks_ssl->ssl, ks_ssl->ct_in, ks_ssl->ct_out);
  BIO_set_ssl (ks_ssl->ssl_bio, ks_ssl->ssl, BIO_NOCLOSE);
}

void key_state_ssl_free(struct key_state_ssl *ks_ssl)
{
  if (ks_ssl->ssl) {
#ifdef BIO_DEBUG
    bio_debug_oc ("close ssl_bio", ks_ssl->ssl_bio);
    bio_debug_oc ("close ct_in", ks_ssl->ct_in);
    bio_debug_oc ("close ct_out", ks_ssl->ct_out);
#endif
    BIO_free_all(ks_ssl->ssl_bio);
    SSL_free (ks_ssl->ssl);
  }
}

int
key_state_write_plaintext (struct key_state_ssl *ks_ssl, struct buffer *buf)
{
  int ret = 0;
  perf_push (PERF_BIO_WRITE_PLAINTEXT);

#ifdef USE_OPENSSL
  ASSERT (NULL != ks_ssl);

  ret = bio_write (ks_ssl->ssl_bio, BPTR(buf), BLEN(buf),
      "tls_write_plaintext");
  bio_write_post (ret, buf);
#endif /* USE_OPENSSL */

  perf_pop ();
  return ret;
}

int
key_state_write_plaintext_const (struct key_state_ssl *ks_ssl, const uint8_t *data, int len)
{
  int ret = 0;
  perf_push (PERF_BIO_WRITE_PLAINTEXT);

  ASSERT (NULL != ks_ssl);

  ret = bio_write (ks_ssl->ssl_bio, data, len, "tls_write_plaintext_const");

  perf_pop ();
  return ret;
}

int
key_state_read_ciphertext (struct key_state_ssl *ks_ssl, struct buffer *buf,
    int maxlen)
{
  int ret = 0;
  perf_push (PERF_BIO_READ_CIPHERTEXT);

  ASSERT (NULL != ks_ssl);

  ret = bio_read (ks_ssl->ct_out, buf, maxlen, "tls_read_ciphertext");

  perf_pop ();
  return ret;
}

int
key_state_write_ciphertext (struct key_state_ssl *ks_ssl, struct buffer *buf)
{
  int ret = 0;
  perf_push (PERF_BIO_WRITE_CIPHERTEXT);

  ASSERT (NULL != ks_ssl);

  ret = bio_write (ks_ssl->ct_in, BPTR(buf), BLEN(buf), "tls_write_ciphertext");
  bio_write_post (ret, buf);

  perf_pop ();
  return ret;
}

int
key_state_read_plaintext (struct key_state_ssl *ks_ssl, struct buffer *buf,
    int maxlen)
{
  int ret = 0;
  perf_push (PERF_BIO_READ_PLAINTEXT);

  ASSERT (NULL != ks_ssl);

  ret = bio_read (ks_ssl->ssl_bio, buf, maxlen, "tls_read_plaintext");

  perf_pop ();
  return ret;
}

/* **************************************
 *
 * Information functions
 *
 * Print information for the end user.
 *
 ***************************************/
void
print_details (struct key_state_ssl * ks_ssl, const char *prefix)
{
  SSL_CIPHER *ciph;
  X509 *cert;
  char s1[256];
  char s2[256];

  s1[0] = s2[0] = 0;
  ciph = SSL_get_current_cipher (ks_ssl->ssl);
  openvpn_snprintf (s1, sizeof (s1), "%s %s, cipher %s %s",
		    prefix,
		    SSL_get_version (ks_ssl->ssl),
		    SSL_CIPHER_get_version (ciph),
		    SSL_CIPHER_get_name (ciph));
  cert = SSL_get_peer_certificate (ks_ssl->ssl);
  if (cert != NULL)
    {
      EVP_PKEY *pkey = X509_get_pubkey (cert);
      if (pkey != NULL)
	{
	  if (pkey->type == EVP_PKEY_RSA && pkey->pkey.rsa != NULL
	      && pkey->pkey.rsa->n != NULL)
	    {
	      openvpn_snprintf (s2, sizeof (s2), ", %d bit RSA",
				BN_num_bits (pkey->pkey.rsa->n));
	    }
	  else if (pkey->type == EVP_PKEY_DSA && pkey->pkey.dsa != NULL
		   && pkey->pkey.dsa->p != NULL)
	    {
	      openvpn_snprintf (s2, sizeof (s2), ", %d bit DSA",
				BN_num_bits (pkey->pkey.dsa->p));
	    }
	  EVP_PKEY_free (pkey);
	}
      X509_free (cert);
    }
  /* The SSL API does not allow us to look at temporary RSA/DH keys,
   * otherwise we should print their lengths too */
  msg (D_HANDSHAKE, "%s%s", s1, s2);
}

void
show_available_tls_ciphers ()
{
  SSL_CTX *ctx;
  SSL *ssl;
  const char *cipher_name;
  int priority = 0;

  ctx = SSL_CTX_new (TLSv1_method ());
  if (!ctx)
    msg (M_SSLERR, "Cannot create SSL_CTX object");

  ssl = SSL_new (ctx);
  if (!ssl)
    msg (M_SSLERR, "Cannot create SSL object");

  printf ("Available TLS Ciphers,\n");
  printf ("listed in order of preference:\n\n");
  while ((cipher_name = SSL_get_cipher_list (ssl, priority++)))
    printf ("%s\n", cipher_name);
  printf ("\n");

  SSL_free (ssl);
  SSL_CTX_free (ctx);
}

void
get_highest_preference_tls_cipher (char *buf, int size)
{
  SSL_CTX *ctx;
  SSL *ssl;
  const char *cipher_name;

  ctx = SSL_CTX_new (TLSv1_method ());
  if (!ctx)
    msg (M_SSLERR, "Cannot create SSL_CTX object");
  ssl = SSL_new (ctx);
  if (!ssl)
    msg (M_SSLERR, "Cannot create SSL object");

  cipher_name = SSL_get_cipher_list (ssl, 0);
  strncpynt (buf, cipher_name, size);

  SSL_free (ssl);
  SSL_CTX_free (ctx);
}