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
|
/* ========================================================================
* Copyright 2019-2021 Eduardo Chappa
* Copyright 2008-2009 Mark Crispin
* ========================================================================
*/
/*
* Program: SSL authentication/encryption module
*
* Author: Mark Crispin
*
* Date: 22 September 1998
* Last Edited: 8 November 2009
*
* Previous versions of this file were
*
* Copyright 1988-2008 University of Washington
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
*/
#define crypt ssl_private_crypt
#define STRING OPENSSL_STRING
#include <x509v3.h>
#include <ssl.h>
#include <err.h>
#include <pem.h>
#include <buffer.h>
#include <bio.h>
#include <crypto.h>
#include <rand.h>
#ifdef OPENSSL_1_1_0
#include <rsa.h>
#include <bn.h>
#endif /* OPENSSL_1_1_0 */
#undef STRING
#undef crypt
#define SSLBUFLEN 8192
/*
* PCI auditing compliance, disable:
* SSLv2
* anonymous D-H (no certificate
* export encryption ciphers (40 and 56 bits)
* low encryption cipher suites (40 and 56 bits, excluding export)
* null encryption (disabling implied by "ALL")
*
* UW imapd just disables low-grade and null ("ALL:!LOW"). This setting
* will break clients that attempt to use the newly-prohibited mechanisms.
*
* I question the value of disabling SSLv2, as opposed to disabling the SSL
* ports (e.g., 993 for IMAP, 995 for POP3) and using TLS exclusively.
*/
#define SSLCIPHERLIST "ALL:!SSLv2:!ADH:!EXP:!LOW"
/* SSL I/O stream */
typedef struct ssl_stream {
TCPSTREAM *tcpstream; /* TCP stream */
SSL_CTX *context; /* SSL context */
SSL *con; /* SSL connection */
int ictr; /* input counter */
char *iptr; /* input pointer */
char ibuf[SSLBUFLEN]; /* input buffer */
} SSLSTREAM;
#include "sslio.h"
/* Function prototypes */
int ssl_disable_mask(int ssl_version, int direction);
const SSL_METHOD *ssl_connect_mthd(int flag, int *minv, int *maxv);
static SSLSTREAM *ssl_start(TCPSTREAM *tstream,char *host,unsigned long flags);
static char *ssl_start_work (SSLSTREAM *stream,char *host,unsigned long flags);
static int ssl_open_verify (int ok,X509_STORE_CTX *ctx);
static char *ssl_validate_cert (X509 *cert,char *host);
static long ssl_compare_hostnames (unsigned char *s,unsigned char *pat);
static char *ssl_getline_work (SSLSTREAM *stream,unsigned long *size,
long *contd);
static long ssl_abort (SSLSTREAM *stream);
#ifdef OPENSSL_1_1_0
#define SSL_CTX_TYPE SSL_CTX
#else
#define SSL_CTX_TYPE SSL
#endif /* OPENSSL_1_1_0 */
static RSA *ssl_genkey (SSL_CTX_TYPE *con,int export,int keylength);
typedef struct ssl_versions_s {
char *name;
int version;
} SSL_VERSIONS_S;
int
pith_ssl_encryption_version(char *s)
{
SSL_VERSIONS_S ssl_versions[] = {
{ "no_min", 0 },
{ "ssl3", SSL3_VERSION },
{ "tls1", TLS1_VERSION },
{ "tls1_1", TLS1_1_VERSION },
{ "tls1_2", TLS1_2_VERSION },
#ifdef TLS1_3_VERSION
{ "tls1_3", TLS1_3_VERSION },
#endif /* TLS1_3_VERSION */
{ "no_max", 0 }, /* set this last in the list */
{ NULL, 0 },
};
int i;
if (s == NULL || *s == '\0')
return -1;
for (i = 0; ssl_versions[i].name != NULL; i++)
if (strcmp(ssl_versions[i].name, s) == 0)
break;
if (strcmp(s, "no_max") == 0) i--;
return ssl_versions[i].name != NULL ? ssl_versions[i].version : -1;
}
/* Secure Sockets Layer network driver dispatch */
static struct ssl_driver ssldriver = {
ssl_open, /* open connection */
ssl_aopen, /* open preauthenticated connection */
ssl_getline, /* get a line */
ssl_getbuffer, /* get a buffer */
ssl_soutr, /* output pushed data */
ssl_sout, /* output string */
ssl_close, /* close connection */
ssl_host, /* return host name */
ssl_remotehost, /* return remote host name */
ssl_port, /* return port number */
ssl_localhost, /* return local host name */
ssl_getsize /* return needed number of bytes */
};
/* non-NIL if doing SSL primary I/O */
static SSLSTDIOSTREAM *sslstdio = NIL;
static char *start_tls = NIL; /* non-NIL if start TLS requested */
/* One-time SSL initialization */
static int sslonceonly = 0;
void ssl_onceonlyinit (void)
{
if (!sslonceonly++) { /* only need to call it once */
int fd;
char tmp[MAILTMPLEN];
struct stat sbuf;
/* if system doesn't have /dev/urandom */
if (stat ("/dev/urandom",&sbuf)) {
strcpy(tmp, "SSLXXXXXX");
while ((fd = mkstemp(tmp)) < 0) sleep (1);
fstat (fd,&sbuf); /* get information about the file */
close (fd); /* flush descriptor */
unlink (tmp); /* don't need the file */
/* not great but it'll have to do */
sprintf (tmp + strlen (tmp),"%.80s%lx%.80s%lx%lx%lx%lx%lx",
tcp_serveraddr (),(unsigned long) tcp_serverport (),
tcp_clientaddr (),(unsigned long) tcp_clientport (),
(unsigned long) sbuf.st_ino,(unsigned long) time (0),
(unsigned long) gethostid (),(unsigned long) getpid ());
RAND_seed (tmp,strlen (tmp));
}
/* apply runtime linkage */
mail_parameters (NIL,SET_SSLDRIVER,(void *) &ssldriver);
mail_parameters (NIL,SET_SSLSTART,(void *) ssl_start);
#ifdef OPENSSL_1_1_0
OPENSSL_init_ssl(0, NULL);
#else
SSL_library_init (); /* add all algorithms */
#endif /* OPENSSL_1_1_0 */
}
}
/* SSL open
* Accepts: host name
* contact service name
* contact port number
* Returns: SSL stream if success else NIL
*/
SSLSTREAM *ssl_open (char *host,char *service,unsigned long port)
{
TCPSTREAM *stream = tcp_open (host,service,port);
return stream ? ssl_start (stream,host,port) : NIL;
}
/* SSL authenticated open
* Accepts: host name
* service name
* returned user name buffer
* Returns: SSL stream if success else NIL
*/
SSLSTREAM *ssl_aopen (NETMBX *mb,char *service,char *usrbuf)
{
return NIL; /* don't use this mechanism with SSL */
}
typedef struct ssl_disable_s {
int version;
int disable_code;
} SSL_DISABLE_S;
SSL_DISABLE_S ssl_disable[] = {
{SSL2_VERSION, SSL_OP_NO_SSLv2},
{SSL3_VERSION, SSL_OP_NO_SSLv3},
{TLS1_VERSION, SSL_OP_NO_TLSv1},
{TLS1_1_VERSION, SSL_OP_NO_TLSv1_1},
{TLS1_2_VERSION, SSL_OP_NO_TLSv1_2},
#ifdef TLS1_3_VERSION
{TLS1_3_VERSION, SSL_OP_NO_TLSv1_3},
#endif /* TLS1_3_VERSION */
{0, 0}
};
#define NUMBER_SSL_VERSIONS (sizeof(ssl_disable)/sizeof(ssl_disable[0]) - 1)
/* returns the mask to disable a specific version.
* If version not found, returns 0.
*
* Arguments: version, and direction.
* If direction is -1, returns mask to disable versions less than given version.
* If direction is +1, returns mask to disable versions bigger than given version.
*/
int ssl_disable_mask(int ssl_version, int direction)
{
int rv = 0;
int i;
for(i = 0; ssl_disable[i].version != 0
&& ssl_disable[i].version != ssl_version; i++);
if(i == 0
|| i == NUMBER_SSL_VERSIONS - 1
|| ssl_disable[i].version == 0)
return rv;
i += direction; /* move in the direction */
for(; i >= 0 && i <= NUMBER_SSL_VERSIONS - 1; i += direction)
rv |= ssl_disable[i].disable_code;
return rv;
}
/* ssl_connect_mthd: returns a context pointer to the connection to
* a ssl server
*/
const SSL_METHOD *ssl_connect_mthd(int flag, int *minv, int *maxv)
{
int client_request;
client_request = (flag & NET_TRYTLS1) ? TLS1_VERSION
: (flag & NET_TRYTLS1_1) ? TLS1_1_VERSION
: (flag & NET_TRYTLS1_2) ? TLS1_2_VERSION
#ifdef TLS1_3_VERSION
: (flag & NET_TRYTLS1_3) ? TLS1_3_VERSION
#else
: (flag & NET_TRYTLS1_3) ? -2
#endif
: 0;
*minv = *(int *) mail_parameters(NULL, GET_ENCRYPTION_RANGE_MIN, NULL);
*maxv = *(int *) mail_parameters(NULL, GET_ENCRYPTION_RANGE_MAX, NULL);
/*
* if no special request, negotiate the maximum the client is configured
* to negotiate
*/
if(client_request == 0)
client_request = *maxv;
if(client_request < *minv || client_request > *maxv)
return NIL; /* out of range? bail out */
/* Some Linux distributors seem to believe that it is ok to disable some of
* these methods for their users, so we have to test that every requested
* method has actually been compiled in into their openssl/libressl library.
* Oh well...
*/
#ifndef OPENSSL_1_1_0
if(client_request == SSL3_VERSION)
#ifndef OPENSSL_NO_SSL3_METHOD
return SSLv3_client_method();
#else
return NIL;
#endif /* OPENSSL_NO_SSL3_METHOD */
else if(client_request == TLS1_VERSION)
#ifndef OPENSSL_NO_TLS1_METHOD
return TLSv1_client_method();
#else
return NIL;
#endif /* OPENSSL_NO_TLS1_METHOD */
else if(client_request == TLS1_1_VERSION)
#ifndef OPENSSL_NO_TLS1_1_METHOD
return TLSv1_1_client_method();
#else
return NIL;
#endif /* OPENSSL_NO_TLS1_1_METHOD */
else if(client_request == TLS1_2_VERSION)
#ifndef OPENSSL_NO_TLS1_2_METHOD
return TLSv1_2_client_method();
#else
return NIL;
#endif /* OPENSSL_NO_TLS1_2_METHOD */
#ifdef TLS1_3_VERSION /* this is only reachable if TLS1_3 support exists */
else if(client_request == TLS1_3_VERSION)
#ifndef OPENSSL_NO_TLS1_3_METHOD
return TLS_client_method();
#else
return NIL;
#endif /* #ifndef OPENSSL_NO_TLS1_2_METHOD */
#endif /* TLS1_3_VERSION */
#endif /* ifndef OPENSSL_1_1_0 */
return SSLv23_client_method();
}
/* Start SSL/TLS negotiations
* Accepts: open TCP stream of session
* user's host name
* flags
* Returns: SSL stream if success else NIL
*/
static SSLSTREAM *ssl_start (TCPSTREAM *tstream,char *host,unsigned long flags)
{
char *reason,tmp[MAILTMPLEN];
sslfailure_t sf = (sslfailure_t) mail_parameters (NIL,GET_SSLFAILURE,NIL);
blocknotify_t bn = (blocknotify_t) mail_parameters (NIL,GET_BLOCKNOTIFY,NIL);
void *data = (*bn) (BLOCK_SENSITIVE,NIL);
SSLSTREAM *stream = (SSLSTREAM *) memset (fs_get (sizeof (SSLSTREAM)),0,
sizeof (SSLSTREAM));
stream->tcpstream = tstream; /* bind TCP stream */
/* do the work */
reason = ssl_start_work (stream,host,flags);
(*bn) (BLOCK_NONSENSITIVE,data);
if (reason) { /* failed? */
ssl_close (stream); /* failed to do SSL */
stream = NIL; /* no stream returned */
switch (*reason) { /* analyze reason */
case '*': /* certificate failure */
++reason; /* skip over certificate failure indication */
/* pass to error callback */
if (sf) (*sf) (host,reason,flags);
else { /* no error callback, build error message */
sprintf (tmp,"Certificate failure for %.80s: %.512s",host,reason);
mm_log (tmp,ERROR);
}
case '\0': /* user answered no to certificate callback */
if (flags & NET_TRYSSL) /* return dummy stream to stop tryssl */
stream = (SSLSTREAM *) memset (fs_get (sizeof (SSLSTREAM)),0,
sizeof (SSLSTREAM));
break;
default: /* non-certificate failure */
if (flags & NET_TRYSSL); /* no error output if tryssl */
/* pass to error callback */
else if (sf) (*sf) (host,reason,flags);
else { /* no error callback, build error message */
sprintf (tmp,"TLS/SSL failure for %.80s: %.512s",host,reason);
mm_log (tmp,ERROR);
}
break;
}
}
return stream;
}
/* Start SSL/TLS negotiations worker routine
* Accepts: SSL stream
* user's host name
* flags
* Returns: NIL if success, else error reason
*/
/* evil but I had no choice */
static char *ssl_last_error = NIL;
static char *ssl_last_host = NIL;
static char *ssl_start_work (SSLSTREAM *stream,char *host,unsigned long flags)
{
BIO *bio;
X509 *cert;
unsigned long sl,tl;
int minv, maxv;
int masklow, maskhigh;
char *s,*t,*err,tmp[MAILTMPLEN], buf[256];
char *CAfile, *CApath, *ciphers;
sslcertificatequery_t scq =
(sslcertificatequery_t) mail_parameters (NIL,GET_SSLCERTIFICATEQUERY,NIL);
sslclientcert_t scc =
(sslclientcert_t) mail_parameters (NIL,GET_SSLCLIENTCERT,NIL);
sslclientkey_t sck =
(sslclientkey_t) mail_parameters (NIL,GET_SSLCLIENTKEY,NIL);
if (ssl_last_error) fs_give ((void **) &ssl_last_error);
ssl_last_host = host;
if (!(stream->context = SSL_CTX_new (ssl_connect_mthd(flags, &minv, &maxv))))
return "SSL context failed";
SSL_CTX_set_options (stream->context,0);
masklow = ssl_disable_mask(minv, -1);
maskhigh = ssl_disable_mask(maxv, 1);
SSL_CTX_set_options(stream->context, masklow|maskhigh);
/* disable certificate validation? */
if (flags & NET_NOVALIDATECERT)
SSL_CTX_set_verify (stream->context,SSL_VERIFY_NONE,NIL);
else SSL_CTX_set_verify (stream->context,SSL_VERIFY_PEER,ssl_open_verify);
/* set cipher list */
ciphers = (char *) mail_parameters (NIL,GET_SSLCIPHERS,NIL);
if(ciphers != NIL
&& *ciphers != '\0'
&& !SSL_CTX_set_cipher_list (stream->context,ciphers))
return "No listed ciphers recognized";
/* if a non-standard path desired */
CAfile = (char *) mail_parameters (NIL,GET_SSLCAFILE,NIL);
CApath = (char *) mail_parameters (NIL,GET_SSLCAPATH,NIL);
if (CAfile != NIL || CApath != NIL)
SSL_CTX_load_verify_locations (stream->context, CAfile, CApath);
else /* set default paths to CAs... */
SSL_CTX_set_default_verify_paths (stream->context);
/* Load app certificates */
CAfile = (char *) mail_parameters (NIL,GET_SSLAPPCAFILE,NIL);
CApath = (char *) mail_parameters (NIL,GET_SSLAPPCAPATH,NIL);
if (CAfile != NIL || CApath != NIL)
SSL_CTX_load_verify_locations (stream->context, CAfile, CApath);
/* want to send client certificate? */
if (scc && (s = (*scc) ()) && (sl = strlen (s))) {
if ((cert = PEM_read_bio_X509 (bio = BIO_new_mem_buf (s,sl),NIL,NIL,NIL)) != NULL) {
SSL_CTX_use_certificate (stream->context,cert);
X509_free (cert);
}
BIO_free (bio);
if (!cert) return "SSL client certificate failed";
/* want to supply private key? */
if ((t = (sck ? (*sck) () : s)) && (tl = strlen (t))) {
EVP_PKEY *key;
if ((key = PEM_read_bio_PrivateKey (bio = BIO_new_mem_buf (t,tl),
NIL,NIL,"")) != NULL) {
SSL_CTX_use_PrivateKey (stream->context,key);
EVP_PKEY_free (key);
}
BIO_free (bio);
memset (t,0,tl); /* erase key */
}
if (s != t) memset (s,0,sl);/* erase certificate if different from key */
}
/* create connection */
if (!(stream->con = (SSL *) SSL_new (stream->context)))
return "SSL connection failed";
if (host && !SSL_set_tlsext_host_name(stream->con, host)){
return "Server Name Identification (SNI) failed";
}
bio = BIO_new_socket (stream->tcpstream->tcpsi,BIO_NOCLOSE);
SSL_set_bio (stream->con,bio,bio);
SSL_set_connect_state (stream->con);
if (SSL_in_init (stream->con)) SSL_total_renegotiations (stream->con);
/* now negotiate SSL */
if (SSL_write (stream->con,"",0) < 0)
return ssl_last_error ? ssl_last_error : "SSL negotiation failed";
/* need to validate host names? */
cert = SSL_get_peer_certificate (stream->con);
if (!(flags & NET_NOVALIDATECERT) &&
(err = ssl_validate_cert (cert, host))) {
/* application callback */
X509_NAME_oneline (X509_get_subject_name(cert), buf, sizeof(buf));
if (scq) return (*scq) (err,host,cert ? buf : "???") ? NIL : "";
/* error message to return via mm_log() */
sprintf (tmp,"*%.128s: %.255s",err,cert ? buf : "???");
X509_free(cert);
return ssl_last_error = cpystr (tmp);
}
X509_free(cert);
return NIL;
}
/* SSL certificate verification callback
* Accepts: error flag
* X509 context
* Returns: error flag
*/
static int ssl_open_verify (int ok,X509_STORE_CTX *ctx)
{
char *err,cert[256],tmp[MAILTMPLEN];
sslcertificatequery_t scq =
(sslcertificatequery_t) mail_parameters (NIL,GET_SSLCERTIFICATEQUERY,NIL);
if (!ok) { /* in case failure */
err = (char *) X509_verify_cert_error_string
(X509_STORE_CTX_get_error (ctx));
X509_NAME_oneline (X509_get_subject_name
(X509_STORE_CTX_get_current_cert (ctx)),cert,255);
if (!scq) { /* mm_log() error message if no callback */
sprintf (tmp,"*%.128s: %.255s",err,cert);
ssl_last_error = cpystr (tmp);
}
/* ignore error if application says to */
else if ((*scq) (err,ssl_last_host,cert)) ok = T;
/* application wants punt */
else ssl_last_error = cpystr ("");
}
return ok;
}
/* SSL validate certificate
* Accepts: certificate
* host to validate against
* Returns: NIL if validated, else string of error message
*/
static char *ssl_validate_cert (X509 *cert,char *host)
{
int i,j,n, m = 0;
char *s=NULL,*t,*ret = NIL;
void *ext = NIL;
GENERAL_NAME *name;
X509_NAME *cname;
X509_NAME_ENTRY *e;
char buf[256];
/* make sure have a certificate */
if (!cert) return "No certificate from server";
/* Method 1: locate CN */
#ifndef OPENSSL_1_1_0
if (cert->name == NIL)
ret = "No name in certificate";
else if ((s = strstr (cert->name,"/CN=")) != NIL) {
m++; /* count that we tried this method */
if (t = strchr (s += 4,'/')) *t = '\0';
/* host name matches pattern? */
ret = ssl_compare_hostnames (host,s) ? NIL :
"Server name does not match certificate";
if (t) *t = '/'; /* restore smashed delimiter */
/* if mismatch, see if in extensions */
if (ret && (ext = X509_get_ext_d2i (cert,NID_subject_alt_name,NIL,NIL)) &&
(n = sk_GENERAL_NAME_num (ext)))
/* older versions of OpenSSL use "ia5" instead of dNSName */
for (i = 0; ret && (i < n); i++)
if ((name = sk_GENERAL_NAME_value (ext,i)) &&
(name->type = GEN_DNS) && (s = name->d.ia5->data) &&
ssl_compare_hostnames (host,s)) ret = NIL;
if(ext) GENERAL_NAMES_free(ext);
}
#endif /* OPENSSL_1_1_0 */
/* Method 2, use cname */
if(m == 0 || ret != NIL){
cname = X509_get_subject_name(cert);
for(j = 0, ret = NIL; j < X509_NAME_entry_count(cname) && ret == NIL; j++){
if((e = X509_NAME_get_entry(cname, j)) != NULL){
X509_NAME_get_text_by_OBJ(cname, X509_NAME_ENTRY_get_object(e), buf, sizeof(buf));
s = (char *) buf;
}
else s = NIL;
if (s != NIL) {
/* host name matches pattern? */
ret = ssl_compare_hostnames (host,s) ? NIL :
"Server name does not match certificate";
/* if mismatch, see if in extensions */
if (ret && (ext = X509_get_ext_d2i (cert,NID_subject_alt_name,NIL,NIL)) &&
(n = sk_GENERAL_NAME_num (ext)))
/* older versions of OpenSSL use "ia5" instead of dNSName */
for (i = 0; ret && (i < n); i++)
if ((name = sk_GENERAL_NAME_value (ext,i)) &&
(name->type = GEN_DNS) && (s = name->d.ia5->data) &&
ssl_compare_hostnames (host,s)) ret = NIL;
if(ext) GENERAL_NAMES_free(ext);
}
}
}
if (ret == NIL
#ifndef OPENSSL_1_1_0
&& !cert->name
#endif /* OPENSSL_1_1_0 */
&& !X509_get_subject_name(cert))
ret = "No name in certificate";
if (ret == NIL && s == NIL)
ret = "Unable to locate common name in certificate";
return ret;
}
/* Case-independent wildcard pattern match
* Accepts: base string
* pattern string
* Returns: T if pattern matches base, else NIL
*/
static long ssl_compare_hostnames (unsigned char *s,unsigned char *pat)
{
long ret = NIL;
switch (*pat) {
case '*': /* wildcard */
if (pat[1]) { /* there must be a pattern suffix */
/* there is, scan base against it */
do if (ssl_compare_hostnames (s,pat+1)) ret = LONGT;
while (!ret && (*s != '.') && *s++);
}
break;
case '\0': /* end of pattern */
if (!*s) ret = LONGT; /* success if base is also at end */
break;
default: /* non-wildcard, recurse if match */
if (!compare_uchar (*pat,*s)) ret = ssl_compare_hostnames (s+1,pat+1);
break;
}
return ret;
}
/* SSL receive line
* Accepts: SSL stream
* Returns: text line string or NIL if failure
*/
char *ssl_getline (SSLSTREAM *stream)
{
unsigned long n,contd;
char *ret = ssl_getline_work (stream,&n,&contd);
if (ret && contd) { /* got a line needing continuation? */
STRINGLIST *stl = mail_newstringlist ();
STRINGLIST *stc = stl;
do { /* collect additional lines */
stc->text.data = (unsigned char *) ret;
stc->text.size = n;
stc = stc->next = mail_newstringlist ();
ret = ssl_getline_work (stream,&n,&contd);
} while (ret && contd);
if (ret) { /* stash final part of line on list */
stc->text.data = (unsigned char *) ret;
stc->text.size = n;
/* determine how large a buffer we need */
for (n = 0, stc = stl; stc; stc = stc->next) n += stc->text.size;
ret = fs_get (n + 1); /* copy parts into buffer */
for (n = 0, stc = stl; stc; n += stc->text.size, stc = stc->next)
memcpy (ret + n,stc->text.data,stc->text.size);
ret[n] = '\0';
}
mail_free_stringlist (&stl);/* either way, done with list */
}
return ret;
}
char *ssl_getsize (SSLSTREAM *stream, unsigned long size)
{
char *ret = NIL;
unsigned long got = 0L, need = size, n;
do {
if(!ssl_getdata (stream)) return ret; /* return what we have */
n = stream->ictr < need ? stream->ictr : need;
fs_resize((void **) &ret, (got + n + 1)*sizeof(char));
memcpy(ret + got, stream->iptr, n);
ret[got+n] = '\0';
got += n;
need -= n;
stream->iptr += n;
stream->ictr -= n;
} while (need > 0);
return ret;
}
/* SSL receive line or partial line
* Accepts: SSL stream
* pointer to return size
* pointer to return continuation flag
* Returns: text line string, size and continuation flag, or NIL if failure
*/
static char *ssl_getline_work (SSLSTREAM *stream,unsigned long *size,
long *contd)
{
unsigned long n;
char *s,*ret,c,d;
*contd = NIL; /* assume no continuation */
/* make sure have data */
if (!ssl_getdata (stream)) return NIL;
for (s = stream->iptr, n = 0, c = '\0'; stream->ictr--; n++, c = d) {
d = *stream->iptr++; /* slurp another character */
if ((c == '\015') && (d == '\012')) {
ret = (char *) fs_get (n--);
memcpy (ret,s,*size = n); /* copy into a free storage string */
ret[n] = '\0'; /* tie off string with null */
return ret;
}
}
/* copy partial string from buffer */
memcpy ((ret = (char *) fs_get (n)),s,*size = n);
/* get more data from the net */
if (!ssl_getdata (stream)) fs_give ((void **) &ret);
/* special case of newline broken by buffer */
else if ((c == '\015') && (*stream->iptr == '\012')) {
stream->iptr++; /* eat the line feed */
stream->ictr--;
ret[*size = --n] = '\0'; /* tie off string with null */
}
else *contd = LONGT; /* continuation needed */
return ret;
}
/* SSL receive buffer
* Accepts: SSL stream
* size in bytes
* buffer to read into
* Returns: T if success, NIL otherwise
*/
long ssl_getbuffer (SSLSTREAM *stream,unsigned long size,char *buffer)
{
unsigned long n;
while (size > 0) { /* until request satisfied */
if (!ssl_getdata (stream)) return NIL;
n = min (size,stream->ictr);/* number of bytes to transfer */
/* do the copy */
memcpy (buffer,stream->iptr,n);
buffer += n; /* update pointer */
stream->iptr += n;
size -= n; /* update # of bytes to do */
stream->ictr -= n;
}
buffer[0] = '\0'; /* tie off string */
return T;
}
/* SSL receive data
* Accepts: TCP/IP stream
* Returns: T if success, NIL otherwise
*/
long ssl_getdata (SSLSTREAM *stream)
{
int i,sock;
fd_set fds,efds;
struct timeval tmo;
tcptimeout_t tmoh = (tcptimeout_t) mail_parameters (NIL,GET_TIMEOUT,NIL);
long ttmo_read = (long) mail_parameters (NIL,GET_READTIMEOUT,NIL);
time_t t = time (0);
blocknotify_t bn = (blocknotify_t) mail_parameters (NIL,GET_BLOCKNOTIFY,NIL);
if (!stream->con || ((sock = SSL_get_fd (stream->con)) < 0)) return NIL;
/* tcp_unix should have prevented this */
if (sock >= FD_SETSIZE) fatal ("unselectable socket in ssl_getdata()");
(*bn) (BLOCK_TCPREAD,NIL);
while (stream->ictr < 1) { /* if nothing in the buffer */
time_t tl = time (0); /* start of request */
time_t now = tl;
int ti = ttmo_read ? now + ttmo_read : 0;
if (SSL_pending (stream->con)) i = 1;
else {
if (tcpdebug) mm_log ("Reading SSL data",TCPDEBUG);
tmo.tv_usec = 0;
FD_ZERO (&fds); /* initialize selection vector */
FD_ZERO (&efds); /* handle errors too */
FD_SET (sock,&fds); /* set bit in selection vector */
FD_SET (sock,&efds); /* set bit in error selection vector */
errno = NIL; /* block and read */
do { /* block under timeout */
tmo.tv_sec = ti ? ti - now : 0;
i = select (sock+1,&fds,0,&efds,ti ? &tmo : 0);
now = time (0); /* fake timeout if interrupt & time expired */
if ((i < 0) && (errno == EINTR) && ti && (ti <= now)) i = 0;
} while ((i < 0) && (errno == EINTR));
}
if (i) { /* non-timeout result from select? */
errno = 0; /* just in case */
if (i > 0) /* read what we can */
while (((i = SSL_read (stream->con,stream->ibuf,SSLBUFLEN)) < 0) &&
((errno == EINTR) ||
(SSL_get_error (stream->con,i) == SSL_ERROR_WANT_READ)));
if (i <= 0) { /* error seen? */
if (tcpdebug) {
char *s,tmp[MAILTMPLEN];
if (i) sprintf (s = tmp,"SSL data read I/O error %d SSL error %d",
errno,SSL_get_error (stream->con,i));
else s = "SSL data read end of file";
mm_log (s,TCPDEBUG);
}
return ssl_abort (stream);
}
stream->iptr = stream->ibuf;/* point at TCP buffer */
stream->ictr = i; /* set new byte count */
if (tcpdebug) mm_log ("Successfully read SSL data",TCPDEBUG);
}
/* timeout, punt unless told not to */
else if (!tmoh || !(*tmoh) (now - t,now - tl, stream->tcpstream->host)) {
if (tcpdebug) mm_log ("SSL data read timeout",TCPDEBUG);
return ssl_abort (stream);
}
}
(*bn) (BLOCK_NONE,NIL);
return T;
}
/* SSL send string as record
* Accepts: SSL stream
* string pointer
* Returns: T if success else NIL
*/
long ssl_soutr (SSLSTREAM *stream,char *string)
{
return ssl_sout (stream,string,(unsigned long) strlen (string));
}
/* SSL send string
* Accepts: SSL stream
* string pointer
* byte count
* Returns: T if success else NIL
*/
long ssl_sout (SSLSTREAM *stream,char *string,unsigned long size)
{
long i;
blocknotify_t bn = (blocknotify_t) mail_parameters (NIL,GET_BLOCKNOTIFY,NIL);
if (!stream->con) return NIL;
(*bn) (BLOCK_TCPWRITE,NIL);
if (tcpdebug) mm_log ("Writing to SSL",TCPDEBUG);
/* until request satisfied */
for (i = 0; size > 0; string += i,size -= i)
/* write as much as we can */
if ((i = SSL_write (stream->con,string,(int) min (SSLBUFLEN,size))) < 0) {
if (tcpdebug) {
char tmp[MAILTMPLEN];
sprintf (tmp,"SSL data write I/O error %d SSL error %d",
errno,SSL_get_error (stream->con,i));
mm_log (tmp,TCPDEBUG);
}
return ssl_abort (stream);/* write failed */
}
if (tcpdebug) mm_log ("successfully wrote to TCP",TCPDEBUG);
(*bn) (BLOCK_NONE,NIL);
return LONGT; /* all done */
}
/* SSL close
* Accepts: SSL stream
*/
void ssl_close (SSLSTREAM *stream)
{
ssl_abort (stream); /* nuke the stream */
fs_give ((void **) &stream); /* flush the stream */
}
/* SSL abort stream
* Accepts: SSL stream
* Returns: NIL always
*/
static long ssl_abort (SSLSTREAM *stream)
{
blocknotify_t bn = (blocknotify_t) mail_parameters (NIL,GET_BLOCKNOTIFY,NIL);
if (stream->con) { /* close SSL connection */
SSL_shutdown (stream->con);
SSL_free (stream->con);
stream->con = NIL;
}
if (stream->context) { /* clean up context */
SSL_CTX_free (stream->context);
stream->context = NIL;
}
if (stream->tcpstream) { /* close TCP stream */
tcp_close (stream->tcpstream);
stream->tcpstream = NIL;
}
(*bn) (BLOCK_NONE,NIL);
return NIL;
}
/* SSL get host name
* Accepts: SSL stream
* Returns: host name for this stream
*/
char *ssl_host (SSLSTREAM *stream)
{
return stream ? tcp_host (stream->tcpstream) : "UNKNOWN";
}
/* SSL get remote host name
* Accepts: SSL stream
* Returns: host name for this stream
*/
char *ssl_remotehost (SSLSTREAM *stream)
{
return tcp_remotehost (stream->tcpstream);
}
/* SSL return port for this stream
* Accepts: SSL stream
* Returns: port number for this stream
*/
unsigned long ssl_port (SSLSTREAM *stream)
{
return tcp_port (stream->tcpstream);
}
/* SSL get local host name
* Accepts: SSL stream
* Returns: local host name
*/
char *ssl_localhost (SSLSTREAM *stream)
{
return tcp_localhost (stream->tcpstream);
}
/* Start TLS
* Accepts: /etc/services service name
* Returns: cpystr'd error string if TLS failed, else NIL for success
*/
char *ssl_start_tls (char *server)
{
char tmp[MAILTMPLEN];
struct stat sbuf;
if (sslstdio) return cpystr ("Already in an SSL session");
if (start_tls) return cpystr ("TLS already started");
if (server) { /* build specific certificate/key file name */
sprintf (tmp,"%s/%s-%s.pem",SSL_CERT_DIRECTORY,server,tcp_serveraddr ());
if (stat (tmp,&sbuf)) { /* use non-specific name if no specific file */
sprintf (tmp,"%s/%s.pem",SSL_CERT_DIRECTORY,server);
if (stat (tmp,&sbuf)) return cpystr ("Server certificate not installed");
}
start_tls = server; /* switch to STARTTLS mode */
}
return NIL;
}
/* Init server for SSL
* Accepts: server name
*/
void ssl_server_init (char *server)
{
char cert[MAILTMPLEN],key[MAILTMPLEN];
unsigned long i;
struct stat sbuf;
SSLSTREAM *stream = (SSLSTREAM *) memset (fs_get (sizeof (SSLSTREAM)),0,
sizeof (SSLSTREAM));
ssl_onceonlyinit (); /* make sure algorithms added */
#ifdef OPENSSL_1_1_0
OPENSSL_init_crypto(OPENSSL_INIT_LOAD_CRYPTO_STRINGS, NULL);
OPENSSL_init_ssl(OPENSSL_INIT_LOAD_SSL_STRINGS|OPENSSL_INIT_LOAD_CRYPTO_STRINGS, NULL);
#else
ERR_load_crypto_strings ();
SSL_load_error_strings ();
#endif /* OPENSSL_1_1_0 */
/* build specific certificate/key file names */
sprintf (cert,"%s/%s-%s.pem",SSL_CERT_DIRECTORY,server,tcp_serveraddr ());
sprintf (key,"%s/%s-%s.pem",SSL_KEY_DIRECTORY,server,tcp_serveraddr ());
/* use non-specific name if no specific cert */
if (stat (cert,&sbuf)) sprintf (cert,"%s/%s.pem",SSL_CERT_DIRECTORY,server);
if (stat (key,&sbuf)) { /* use non-specific name if no specific key */
sprintf (key,"%s/%s.pem",SSL_KEY_DIRECTORY,server);
/* use cert file as fallback for key */
if (stat (key,&sbuf)) strcpy (key,cert);
}
/* create context */
#ifdef OPENSSL_1_1_0
if (!(stream->context = SSL_CTX_new (start_tls ?
TLS_server_method () :
SSLv23_server_method ())))
#else
if (!(stream->context = SSL_CTX_new (start_tls ?
TLSv1_server_method () :
SSLv23_server_method ())))
#endif /* OPENSSL_1_1_0 */
syslog (LOG_ALERT,"Unable to create SSL context, host=%.80s",
tcp_clienthost ());
else { /* set context options */
SSL_CTX_set_options (stream->context,SSL_OP_ALL);
/* set cipher list */
if (!SSL_CTX_set_cipher_list (stream->context,SSLCIPHERLIST))
syslog (LOG_ALERT,"Unable to set cipher list %.80s, host=%.80s",
SSLCIPHERLIST,tcp_clienthost ());
/* load certificate */
else if (!SSL_CTX_use_certificate_chain_file (stream->context,cert))
syslog (LOG_ALERT,"Unable to load certificate from %.80s, host=%.80s",
cert,tcp_clienthost ());
/* load key */
else if (!(SSL_CTX_use_RSAPrivateKey_file (stream->context,key,
SSL_FILETYPE_PEM)))
syslog (LOG_ALERT,"Unable to load private key from %.80s, host=%.80s",
key,tcp_clienthost ());
else { /* generate key if needed */
#ifdef OPENSSL_1_1_0
if (0)
ssl_genkey(stream->context, 0, 0);
#else
if (SSL_CTX_need_tmp_RSA (stream->context))
SSL_CTX_set_tmp_rsa_callback (stream->context,ssl_genkey);
#endif /* OPENSSL_1_1_0 */
/* create new SSL connection */
if (!(stream->con = SSL_new (stream->context)))
syslog (LOG_ALERT,"Unable to create SSL connection, host=%.80s",
tcp_clienthost ());
else { /* set file descriptor */
SSL_set_fd (stream->con,0);
/* all OK if accepted */
if (SSL_accept (stream->con) < 0)
syslog (LOG_INFO,"Unable to accept SSL connection, host=%.80s",
tcp_clienthost ());
else { /* server set up */
sslstdio = (SSLSTDIOSTREAM *)
memset (fs_get (sizeof(SSLSTDIOSTREAM)),0,sizeof (SSLSTDIOSTREAM));
sslstdio->sslstream = stream;
/* available space in output buffer */
sslstdio->octr = SSLBUFLEN;
/* current output buffer pointer */
sslstdio->optr = sslstdio->obuf;
/* allow plaintext if disable value was 2 */
if ((long) mail_parameters (NIL,GET_DISABLEPLAINTEXT,NIL) > 1)
mail_parameters (NIL,SET_DISABLEPLAINTEXT,NIL);
/* unhide PLAIN SASL authenticator */
mail_parameters (NIL,UNHIDE_AUTHENTICATOR,"PLAIN");
mail_parameters (NIL,UNHIDE_AUTHENTICATOR,"LOGIN");
return;
}
}
}
}
while ((i = ERR_get_error ()) != 0L) /* SSL failure */
syslog (LOG_ERR,"SSL error status: %.80s",ERR_error_string (i,NIL));
ssl_close (stream); /* punt stream */
exit (1); /* punt this program too */
}
/* Generate one-time key for server
* Accepts: SSL connection
* export flag
* keylength
* Returns: generated key, always
*/
static RSA *ssl_genkey (SSL_CTX_TYPE *con,int export,int keylength)
{
unsigned long i;
static RSA *key = NIL;
if (!key) { /* if don't have a key already */
/* generate key */
#ifdef OPENSSL_1_1_0
BIGNUM *e = BN_new();
if (!RSA_generate_key_ex (key, export ? keylength : 1024, e,NIL)) {
#else
if (!(key = RSA_generate_key (export ? keylength : 1024,RSA_F4,NIL,NIL))) {
#endif /* OPENSSL_1_1_0 */
syslog (LOG_ALERT,"Unable to generate temp key, host=%.80s",
tcp_clienthost ());
while ((i = ERR_get_error ()) != 0L)
syslog (LOG_ALERT,"SSL error status: %s",ERR_error_string (i,NIL));
exit (1);
}
#ifdef OPENSSL_1_1_0
BN_free(e);
e = NULL;
#endif /* OPENSSL_1_1_0 */
}
return key;
}
/* Wait for stdin input
* Accepts: timeout in seconds
* Returns: T if have input on stdin, else NIL
*/
long ssl_server_input_wait (long seconds)
{
int i,sock;
fd_set fds,efd;
struct timeval tmo;
SSLSTREAM *stream;
if (!sslstdio) return server_input_wait (seconds);
/* input available in buffer */
if (((stream = sslstdio->sslstream)->ictr > 0) ||
!stream->con || ((sock = SSL_get_fd (stream->con)) < 0)) return LONGT;
/* sock ought to be 0 always */
if (sock >= FD_SETSIZE) fatal ("unselectable socket in ssl_getdata()");
/* input available from SSL */
if (SSL_pending (stream->con) &&
((i = SSL_read (stream->con,stream->ibuf,SSLBUFLEN)) > 0)) {
stream->iptr = stream->ibuf;/* point at TCP buffer */
stream->ictr = i; /* set new byte count */
return LONGT;
}
FD_ZERO (&fds); /* initialize selection vector */
FD_ZERO (&efd); /* initialize selection vector */
FD_SET (sock,&fds); /* set bit in selection vector */
FD_SET (sock,&efd); /* set bit in selection vector */
tmo.tv_sec = seconds; tmo.tv_usec = 0;
/* see if input available from the socket */
return select (sock+1,&fds,0,&efd,&tmo) ? LONGT : NIL;
}
#include "sslstdio.c"
|