-
Notifications
You must be signed in to change notification settings - Fork 166
/
dns-stuff.c
2506 lines (2158 loc) · 64.2 KB
/
dns-stuff.c
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
/* dns-stuff.c - DNS related code including CERT RR (rfc-4398)
* Copyright (C) 2003, 2005, 2006, 2009 Free Software Foundation, Inc.
* Copyright (C) 2005, 2006, 2009, 2015. 2016 Werner Koch
*
* This file is part of GnuPG.
*
* This file is free software; you can redistribute it and/or modify
* it under the terms of either
*
* - the GNU Lesser General Public License as published by the Free
* Software Foundation; either version 3 of the License, or (at
* your option) any later version.
*
* or
*
* - the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at
* your option) any later version.
*
* or both in parallel, as here.
*
* This file is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <https://www.gnu.org/licenses/>.
*/
#include <config.h>
#include <sys/types.h>
#ifdef HAVE_W32_SYSTEM
# define WIN32_LEAN_AND_MEAN
# ifdef HAVE_WINSOCK2_H
# include <winsock2.h>
# include <ws2tcpip.h>
# endif
# include <windows.h>
# include <iphlpapi.h>
#else
# if HAVE_SYSTEM_RESOLVER
# include <netinet/in.h>
# include <arpa/nameser.h>
# include <resolv.h>
# endif
# include <netdb.h>
#endif
#ifdef HAVE_STAT
# include <sys/stat.h>
#endif
#include <string.h>
#include <unistd.h>
/* William Ahern's DNS library, included as a source copy. */
#ifdef USE_LIBDNS
# include "dns.h"
#endif
/* dns.c has a dns_p_free but it is not exported. We use our own
* wrapper here so that we do not accidentally use xfree which would
* be wrong for dns.c allocated data. */
#define dns_free(a) free ((a))
#ifdef WITHOUT_NPTH /* Give the Makefile a chance to build without Pth. */
# undef USE_NPTH
#endif
#ifdef USE_NPTH
# include <npth.h>
#endif
#include "./dirmngr-err.h"
#include "../common/util.h"
#include "../common/host2net.h"
#include "dirmngr-status.h"
#include "dns-stuff.h"
#ifdef USE_NPTH
# define my_unprotect() npth_unprotect ()
# define my_protect() npth_protect ()
#else
# define my_unprotect() do { } while(0)
# define my_protect() do { } while(0)
#endif
/* We allow the use of 0 instead of AF_UNSPEC - check this assumption. */
#if AF_UNSPEC != 0
# error AF_UNSPEC does not have the value 0
#endif
/* Windows does not support the AI_ADDRCONFIG flag - use zero instead. */
#ifndef AI_ADDRCONFIG
# define AI_ADDRCONFIG 0
#endif
/* Not every installation has gotten around to supporting SRVs or
CERTs yet... */
#ifndef T_SRV
#define T_SRV 33
#endif
#undef T_CERT
#define T_CERT 37
/* The standard SOCKS and TOR ports. */
#define SOCKS_PORT 1080
#define TOR_PORT 9050
#define TOR_PORT2 9150 /* (Used by the Tor browser) */
/* The default nameserver used in Tor mode. */
#define DEFAULT_NAMESERVER "8.8.8.8"
/* The default timeout in seconds for libdns requests. */
#define DEFAULT_TIMEOUT 30
#define RESOLV_CONF_NAME "/etc/resolv.conf"
/* Two flags to enable verbose and debug mode. */
static int opt_verbose;
static int opt_debug;
/* The timeout in seconds for libdns requests. */
static int opt_timeout;
/* The flag to disable IPv4 access - right now this only skips
* returned A records. */
static int opt_disable_ipv4;
/* The flag to disable IPv6 access - right now this only skips
* returned AAAA records. */
static int opt_disable_ipv6;
/* If set force the use of the standard resolver. */
static int standard_resolver;
/* If set use recursive resolver when available. */
static int recursive_resolver;
/* If set Tor mode shall be used. */
static int tor_mode;
/* A string with the nameserver IP address used with Tor.
(40 should be sufficient for v6 but we add some extra for a scope.) */
static char tor_nameserver[40+20];
/* Two strings to hold the credentials presented to Tor. */
static char tor_socks_user[30];
static char tor_socks_password[20];
/* To avoid checking the interface too often we cache the result. */
static struct
{
unsigned int valid:1;
unsigned int v4:1;
unsigned int v6:1;
} cached_inet_support;
#ifdef USE_LIBDNS
/* Libdns global data. */
struct libdns_s
{
struct dns_resolv_conf *resolv_conf;
struct dns_hosts *hosts;
struct dns_hints *hints;
struct sockaddr_storage socks_host;
} libdns;
/* If this flag is set, libdns shall be reinited for the next use. */
static int libdns_reinit_pending;
/* The Tor port to be used. */
static int libdns_tor_port;
#endif /*USE_LIBDNS*/
/* Calling this function with YES set to True forces the use of the
* standard resolver even if dirmngr has been built with support for
* an alternative resolver. */
void
enable_standard_resolver (int yes)
{
standard_resolver = yes;
}
/* Return true if the standard resolver is used. */
int
standard_resolver_p (void)
{
return standard_resolver;
}
/* Calling this function with YES switches libdns into recursive mode.
* It has no effect on the standard resolver. */
void
enable_recursive_resolver (int yes)
{
recursive_resolver = yes;
#ifdef USE_LIBDNS
libdns_reinit_pending = 1;
#endif
}
/* Return true iff the recursive resolver is used. */
int
recursive_resolver_p (void)
{
#if USE_LIBDNS
return !standard_resolver && recursive_resolver;
#else
return 0;
#endif
}
/* Puts this module eternally into Tor mode. When called agained with
* NEW_CIRCUIT request a new TOR circuit for the next DNS query. */
void
enable_dns_tormode (int new_circuit)
{
if (!*tor_socks_user || new_circuit)
{
static unsigned int counter;
gpgrt_snprintf (tor_socks_user, sizeof tor_socks_user,
"dirmngr-%lu", (unsigned long)getpid ());
gpgrt_snprintf (tor_socks_password, sizeof tor_socks_password,
"p%u", counter);
counter++;
}
tor_mode = 1;
}
/* Disable tor mode. */
void
disable_dns_tormode (void)
{
tor_mode = 0;
}
/* Set verbosity and debug mode for this module. */
void
set_dns_verbose (int verbose, int debug)
{
opt_verbose = verbose;
opt_debug = debug;
}
/* Set the Disable-IPv4 flag so that the name resolver does not return
* A addresses. */
void
set_dns_disable_ipv4 (int yes)
{
opt_disable_ipv4 = !!yes;
}
/* Set the Disable-IPv6 flag so that the name resolver does not return
* AAAA addresses. */
void
set_dns_disable_ipv6 (int yes)
{
opt_disable_ipv6 = !!yes;
}
/* Set the timeout for libdns requests to SECONDS. A value of 0 sets
* the default timeout and values are capped at 10 minutes. */
void
set_dns_timeout (int seconds)
{
if (!seconds)
seconds = DEFAULT_TIMEOUT;
else if (seconds < 1)
seconds = 1;
else if (seconds > 600)
seconds = 600;
opt_timeout = seconds;
}
/* Change the default IP address of the nameserver to IPADDR. The
address needs to be a numerical IP address and will be used for the
next DNS query. Note that this is only used in Tor mode. */
void
set_dns_nameserver (const char *ipaddr)
{
strncpy (tor_nameserver, ipaddr? ipaddr : DEFAULT_NAMESERVER,
sizeof tor_nameserver -1);
tor_nameserver[sizeof tor_nameserver -1] = 0;
#ifdef USE_LIBDNS
libdns_reinit_pending = 1;
libdns_tor_port = 0; /* Start again with the default port. */
#endif
}
/* Free an addressinfo linked list as returned by resolve_dns_name. */
void
free_dns_addrinfo (dns_addrinfo_t ai)
{
while (ai)
{
dns_addrinfo_t next = ai->next;
xfree (ai);
ai = next;
}
}
#ifndef HAVE_W32_SYSTEM
/* Return H_ERRNO mapped to a gpg-error code. Will never return 0. */
static gpg_error_t
get_h_errno_as_gpg_error (void)
{
gpg_err_code_t ec;
switch (h_errno)
{
case HOST_NOT_FOUND: ec = GPG_ERR_NO_NAME; break;
case TRY_AGAIN: ec = GPG_ERR_TRY_LATER; break;
case NO_RECOVERY: ec = GPG_ERR_SERVER_FAILED; break;
case NO_DATA: ec = GPG_ERR_NO_DATA; break;
default: ec = GPG_ERR_UNKNOWN_ERRNO; break;
}
return gpg_error (ec);
}
#endif /*!HAVE_W32_SYSTEM*/
static gpg_error_t
map_eai_to_gpg_error (int ec)
{
gpg_error_t err;
switch (ec)
{
case EAI_AGAIN: err = gpg_error (GPG_ERR_EAGAIN); break;
case EAI_BADFLAGS: err = gpg_error (GPG_ERR_INV_FLAG); break;
case EAI_FAIL: err = gpg_error (GPG_ERR_SERVER_FAILED); break;
case EAI_MEMORY: err = gpg_error (GPG_ERR_ENOMEM); break;
#ifdef EAI_NODATA
case EAI_NODATA: err = gpg_error (GPG_ERR_NO_DATA); break;
#endif
case EAI_NONAME: err = gpg_error (GPG_ERR_NO_NAME); break;
case EAI_SERVICE: err = gpg_error (GPG_ERR_NOT_SUPPORTED); break;
case EAI_FAMILY: err = gpg_error (GPG_ERR_EAFNOSUPPORT); break;
case EAI_SOCKTYPE: err = gpg_error (GPG_ERR_ESOCKTNOSUPPORT); break;
#ifndef HAVE_W32_SYSTEM
# ifdef EAI_ADDRFAMILY
case EAI_ADDRFAMILY:err = gpg_error (GPG_ERR_EADDRNOTAVAIL); break;
# endif
case EAI_SYSTEM: err = gpg_error_from_syserror (); break;
#endif
default: err = gpg_error (GPG_ERR_UNKNOWN_ERRNO); break;
}
return err;
}
#ifdef USE_LIBDNS
static gpg_error_t
libdns_error_to_gpg_error (int serr)
{
gpg_err_code_t ec;
switch (serr)
{
case 0: ec = 0; break;
case DNS_ENOBUFS: ec = GPG_ERR_BUFFER_TOO_SHORT; break;
case DNS_EILLEGAL: ec = GPG_ERR_INV_OBJ; break;
case DNS_EORDER: ec = GPG_ERR_INV_ORDER; break;
case DNS_ESECTION: ec = GPG_ERR_DNS_SECTION; break;
case DNS_EUNKNOWN: ec = GPG_ERR_DNS_UNKNOWN; break;
case DNS_EADDRESS: ec = GPG_ERR_DNS_ADDRESS; break;
case DNS_ENOQUERY: ec = GPG_ERR_DNS_NO_QUERY; break;
case DNS_ENOANSWER:ec = GPG_ERR_DNS_NO_ANSWER; break;
case DNS_EFETCHED: ec = GPG_ERR_ALREADY_FETCHED; break;
case DNS_ESERVICE: ec = GPG_ERR_NOT_SUPPORTED; break;
case DNS_ENONAME: ec = GPG_ERR_NO_NAME; break;
case DNS_EFAIL: ec = GPG_ERR_SERVER_FAILED; break;
case DNS_ECONNFIN: ec = GPG_ERR_DNS_CLOSED; break;
case DNS_EVERIFY: ec = GPG_ERR_DNS_VERIFY; break;
default:
if (serr >= 0)
ec = gpg_err_code_from_errno (serr);
else
ec = GPG_ERR_DNS_UNKNOWN;
break;
}
return gpg_error (ec);
}
#endif /*USE_LIBDNS*/
/* Return true if resolve.conf changed since it was last loaded. */
#ifdef USE_LIBDNS
static int
resolv_conf_changed_p (void)
{
#if defined(HAVE_W32_SYSTEM) || !defined(HAVE_STAT)
return 0;
#else
static time_t last_mtime;
const char *fname = RESOLV_CONF_NAME;
struct stat statbuf;
int changed = 0;
if (stat (fname, &statbuf))
{
log_error ("stat'ing '%s' failed: %s\n",
fname, gpg_strerror (gpg_error_from_syserror ()));
last_mtime = 1; /* Force a "changed" result the next time stat
* works. */
}
else if (!last_mtime)
last_mtime = statbuf.st_mtime;
else if (last_mtime != statbuf.st_mtime)
{
changed = 1;
last_mtime = statbuf.st_mtime;
}
return changed;
#endif
}
#endif /*USE_LIBDNS*/
#ifdef USE_LIBDNS
/* Initialize libdns. Returns 0 on success; prints a diagnostic and
* returns an error code on failure. */
static gpg_error_t
libdns_init (ctrl_t ctrl)
{
gpg_error_t err;
struct libdns_s ld;
int derr;
char *cfgstr = NULL;
const char *fname = NULL;
if (libdns.resolv_conf)
return 0; /* Already initialized. */
memset (&ld, 0, sizeof ld);
ld.resolv_conf = dns_resconf_open (&derr);
if (!ld.resolv_conf)
{
err = libdns_error_to_gpg_error (derr);
log_error ("failed to allocate DNS resconf object: %s\n",
gpg_strerror (err));
goto leave;
}
if (tor_mode)
{
if (!*tor_nameserver)
set_dns_nameserver (NULL);
if (!libdns_tor_port)
libdns_tor_port = TOR_PORT;
cfgstr = xtryasprintf ("[%s]:53", tor_nameserver);
if (!cfgstr)
err = gpg_error_from_syserror ();
else
err = libdns_error_to_gpg_error
(dns_resconf_pton (&ld.resolv_conf->nameserver[0], cfgstr));
if (err)
log_error ("failed to set nameserver '%s': %s\n",
cfgstr, gpg_strerror (err));
if (err)
goto leave;
ld.resolv_conf->options.tcp = DNS_RESCONF_TCP_SOCKS;
xfree (cfgstr);
cfgstr = xtryasprintf ("[%s]:%d", "127.0.0.1", libdns_tor_port);
if (!cfgstr)
err = gpg_error_from_syserror ();
else
err = libdns_error_to_gpg_error
(dns_resconf_pton (&ld.socks_host, cfgstr));
if (err)
{
log_error ("failed to set socks server '%s': %s\n",
cfgstr, gpg_strerror (err));
goto leave;
}
}
else
{
#ifdef HAVE_W32_SYSTEM
ULONG ninfo_len;
PFIXED_INFO ninfo;
PIP_ADDR_STRING pip;
int idx;
ninfo_len = 2048;
ninfo = xtrymalloc (ninfo_len);
if (!ninfo)
{
err = gpg_error_from_syserror ();
goto leave;
}
if (GetNetworkParams (ninfo, &ninfo_len))
{
log_error ("GetNetworkParms failed: %s\n", w32_strerror (-1));
err = gpg_error (GPG_ERR_GENERAL);
xfree (ninfo);
goto leave;
}
for (idx=0, pip = &(ninfo->DnsServerList);
pip && idx < DIM (ld.resolv_conf->nameserver);
pip = pip->Next)
{
if (opt_debug)
log_debug ("dns: dnsserver[%d] '%s'\n", idx, pip->IpAddress.String);
err = libdns_error_to_gpg_error
(dns_resconf_pton (&ld.resolv_conf->nameserver[idx],
pip->IpAddress.String));
if (err)
log_error ("failed to set nameserver[%d] '%s': %s\n",
idx, pip->IpAddress.String, gpg_strerror (err));
else
idx++;
}
xfree (ninfo);
#else /* Unix */
fname = RESOLV_CONF_NAME;
resolv_conf_changed_p (); /* Reset timestamp. */
err = libdns_error_to_gpg_error
(dns_resconf_loadpath (ld.resolv_conf, fname));
if (err)
{
log_error ("failed to load '%s': %s\n", fname, gpg_strerror (err));
goto leave;
}
fname = "/etc/nsswitch.conf";
err = libdns_error_to_gpg_error
(dns_nssconf_loadpath (ld.resolv_conf, fname));
if (err)
{
/* This is not a fatal error: nsswitch.conf is not used on
* all systems; assume classic behavior instead. */
if (gpg_err_code (err) != GPG_ERR_ENOENT)
log_error ("failed to load '%s': %s\n", fname, gpg_strerror (err));
if (opt_debug)
log_debug ("dns: fallback resolution order, files then DNS\n");
ld.resolv_conf->lookup[0] = 'f';
ld.resolv_conf->lookup[1] = 'b';
ld.resolv_conf->lookup[2] = '\0';
err = GPG_ERR_NO_ERROR;
}
else if (!strchr (ld.resolv_conf->lookup, 'b'))
{
/* No DNS resolution type found in the list. This might be
* due to systemd based systems which allow for custom
* keywords which are not known to us and thus we do not
* know whether DNS is wanted or not. Because DNS is
* important for our infrastructure, we forcefully append
* DNS to the end of the list. */
if (strlen (ld.resolv_conf->lookup)+2 < sizeof ld.resolv_conf->lookup)
{
if (opt_debug)
log_debug ("dns: appending DNS to resolution order\n");
strcat (ld.resolv_conf->lookup, "b");
}
else
log_error ("failed to append DNS to resolution order\n");
}
#endif /* Unix */
}
ld.hosts = dns_hosts_open (&derr);
if (!ld.hosts)
{
err = libdns_error_to_gpg_error (derr);
log_error ("failed to initialize hosts file: %s\n", gpg_strerror (err));
goto leave;
}
{
#if HAVE_W32_SYSTEM
char *hosts_path = xtryasprintf ("%s\\System32\\drivers\\etc\\hosts",
getenv ("SystemRoot"));
if (! hosts_path)
{
err = gpg_error_from_syserror ();
goto leave;
}
derr = dns_hosts_loadpath (ld.hosts, hosts_path);
xfree (hosts_path);
#else
derr = dns_hosts_loadpath (ld.hosts, "/etc/hosts");
#endif
if (derr)
{
err = libdns_error_to_gpg_error (derr);
log_error ("failed to load hosts file: %s\n", gpg_strerror (err));
err = 0; /* Do not bail out - having no /etc/hosts is legal. */
}
}
ld.resolv_conf->options.recurse = recursive_resolver_p ();
/* dns_hints_local for stub mode, dns_hints_root for recursive. */
ld.hints = (recursive_resolver
? dns_hints_root (ld.resolv_conf, &derr)
: dns_hints_local (ld.resolv_conf, &derr));
if (!ld.hints)
{
err = libdns_error_to_gpg_error (derr);
log_error ("failed to load DNS hints: %s\n", gpg_strerror (err));
fname = "[dns hints]";
goto leave;
}
/* All fine. Make the data global. */
libdns = ld;
if (opt_debug)
log_debug ("dns: libdns initialized%s\n", tor_mode?" (tor mode)":"");
leave:
if (!fname)
fname = cfgstr;
if (err && fname)
dirmngr_status_printf (ctrl, "WARNING",
"dns_config_problem %u"
" error accessing '%s': %s <%s>",
err, fname, gpg_strerror (err), gpg_strsource (err));
xfree (cfgstr);
return err;
}
#endif /*USE_LIBDNS*/
#ifdef USE_LIBDNS
/* Deinitialize libdns. */
static void
libdns_deinit (void)
{
struct libdns_s ld;
if (!libdns.resolv_conf)
return; /* Not initialized. */
ld = libdns;
memset (&libdns, 0, sizeof libdns);
dns_hints_close (ld.hints);
dns_hosts_close (ld.hosts);
dns_resconf_close (ld.resolv_conf);
}
#endif /*USE_LIBDNS*/
/* SIGHUP action handler for this module. With FORCE set objects are
* all immediately released. */
void
reload_dns_stuff (int force)
{
#ifdef USE_LIBDNS
if (force)
{
libdns_deinit ();
libdns_reinit_pending = 0;
}
else
{
libdns_reinit_pending = 1;
libdns_tor_port = 0; /* Start again with the default port. */
}
#else
(void)force;
#endif
/* We also flush the IPv4/v6 support flag cache. */
cached_inet_support.valid = 0;
}
/* Called from time to time from the housekeeping thread. */
void
dns_stuff_housekeeping (void)
{
/* With the current housekeeping interval of 10 minutes we flush
* that case so that a new or removed interface will be detected not
* later than 10 minutes after it changed. This way the user does
* not need a reload. */
cached_inet_support.valid = 0;
}
#ifdef USE_LIBDNS
/*
* Initialize libdns if needed and open a dns_resolver context.
* Returns 0 on success and stores the new context at R_RES. On
* failure an error code is returned and NULL stored at R_RES.
*/
static gpg_error_t
libdns_res_open (ctrl_t ctrl, struct dns_resolver **r_res)
{
gpg_error_t err;
struct dns_resolver *res;
int derr;
struct dns_options opts = { 0 };
opts.socks_host = &libdns.socks_host;
opts.socks_user = tor_socks_user;
opts.socks_password = tor_socks_password;
*r_res = NULL;
/* Force a reload if resolv.conf has changed. */
if (resolv_conf_changed_p ())
{
if (opt_debug)
log_debug ("dns: resolv.conf changed - forcing reload\n");
libdns_reinit_pending = 1;
}
if (libdns_reinit_pending)
{
libdns_reinit_pending = 0;
libdns_deinit ();
}
err = libdns_init (ctrl);
if (err)
return err;
if (!opt_timeout)
set_dns_timeout (0);
res = dns_res_open (libdns.resolv_conf, libdns.hosts, libdns.hints, NULL,
&opts, &derr);
if (!res)
return libdns_error_to_gpg_error (derr);
*r_res = res;
return 0;
}
#endif /*USE_LIBDNS*/
#ifdef USE_LIBDNS
/* Helper to test whether we need to try again after having switched
* the Tor port. */
static int
libdns_switch_port_p (gpg_error_t err)
{
if (tor_mode && gpg_err_code (err) == GPG_ERR_ECONNREFUSED
&& libdns_tor_port == TOR_PORT)
{
/* Switch port and try again. */
if (opt_debug)
log_debug ("dns: switching from SOCKS port %d to %d\n",
TOR_PORT, TOR_PORT2);
libdns_tor_port = TOR_PORT2;
libdns_reinit_pending = 1;
return 1;
}
return 0;
}
#endif /*USE_LIBDNS*/
#ifdef USE_LIBDNS
/* Wrapper around dns_res_submit. */
static gpg_error_t
libdns_res_submit (struct dns_resolver *res, const char *qname,
enum dns_type qtype, enum dns_class qclass)
{
return libdns_error_to_gpg_error (dns_res_submit (res, qname, qtype, qclass));
}
#endif /*USE_LIBDNS*/
#ifdef USE_LIBDNS
/* Standard event handling loop. */
gpg_error_t
libdns_res_wait (struct dns_resolver *res)
{
gpg_error_t err;
while ((err = libdns_error_to_gpg_error (dns_res_check (res)))
&& gpg_err_code (err) == GPG_ERR_EAGAIN)
{
if (dns_res_elapsed (res) > opt_timeout)
{
err = gpg_error (GPG_ERR_DNS_TIMEOUT);
break;
}
my_unprotect ();
dns_res_poll (res, 1);
my_protect ();
}
return err;
}
#endif /*USE_LIBDNS*/
#ifdef USE_LIBDNS
static gpg_error_t
resolve_name_libdns (ctrl_t ctrl, const char *name, unsigned short port,
int want_family, int want_socktype,
dns_addrinfo_t *r_dai, char **r_canonname)
{
gpg_error_t err;
dns_addrinfo_t daihead = NULL;
dns_addrinfo_t dai;
struct dns_resolver *res = NULL;
struct dns_addrinfo *ai = NULL;
struct addrinfo hints;
struct addrinfo *ent;
char portstr_[21];
char *portstr = NULL;
char *namebuf = NULL;
int derr;
*r_dai = NULL;
if (r_canonname)
*r_canonname = NULL;
memset (&hints, 0, sizeof hints);
hints.ai_family = want_family;
hints.ai_socktype = want_socktype;
hints.ai_flags = AI_ADDRCONFIG;
if (r_canonname)
hints.ai_flags |= AI_CANONNAME;
if (port)
{
snprintf (portstr_, sizeof portstr_, "%hu", port);
portstr = portstr_;
}
err = libdns_res_open (ctrl, &res);
if (err)
goto leave;
if (is_ip_address (name))
{
hints.ai_flags |= AI_NUMERICHOST;
/* libdns does not grok brackets - remove them. */
if (*name == '[' && name[strlen(name)-1] == ']')
{
namebuf = xtrymalloc (strlen (name));
if (!namebuf)
{
err = gpg_error_from_syserror ();
goto leave;
}
strcpy (namebuf, name+1);
namebuf[strlen (namebuf)-1] = 0;
name = namebuf;
}
}
ai = dns_ai_open (name, portstr, 0, &hints, res, &derr);
if (!ai)
{
err = libdns_error_to_gpg_error (derr);
goto leave;
}
/* Loop over all records. */
for (;;)
{
err = libdns_error_to_gpg_error (dns_ai_nextent (&ent, ai));
if (gpg_err_code (err) == GPG_ERR_ENOENT)
{
if (daihead)
err = 0; /* We got some results, we're good. */
break; /* Ready. */
}
if (gpg_err_code (err) == GPG_ERR_EAGAIN)
{
if (dns_ai_elapsed (ai) > opt_timeout)
{
err = gpg_error (GPG_ERR_DNS_TIMEOUT);
goto leave;
}
my_unprotect ();
dns_ai_poll (ai, 1);
my_protect ();
continue;
}
if (err)
goto leave;
if (r_canonname && ! *r_canonname && ent && ent->ai_canonname)
{
*r_canonname = xtrystrdup (ent->ai_canonname);
if (!*r_canonname)
{
err = gpg_error_from_syserror ();
goto leave;
}
/* Libdns appends the root zone part which is problematic
* for most other functions - strip it. */
if (**r_canonname && (*r_canonname)[strlen (*r_canonname)-1] == '.')
(*r_canonname)[strlen (*r_canonname)-1] = 0;
}
dai = xtrymalloc (sizeof *dai);
if (dai == NULL)
{
err = gpg_error_from_syserror ();
goto leave;
}
dai->family = ent->ai_family;
dai->socktype = ent->ai_socktype;
dai->protocol = ent->ai_protocol;
dai->addrlen = ent->ai_addrlen;
memcpy (dai->addr, ent->ai_addr, ent->ai_addrlen);
dai->next = daihead;
daihead = dai;
xfree (ent);
}
leave:
dns_ai_close (ai);
dns_res_close (res);
if (err)
{
if (r_canonname)
{
xfree (*r_canonname);
*r_canonname = NULL;
}
free_dns_addrinfo (daihead);
}
else
*r_dai = daihead;
xfree (namebuf);
return err;
}
#endif /*USE_LIBDNS*/
/* Resolve a name using the standard system function. */
static gpg_error_t
resolve_name_standard (ctrl_t ctrl, const char *name, unsigned short port,
int want_family, int want_socktype,
dns_addrinfo_t *r_dai, char **r_canonname)
{
gpg_error_t err = 0;
dns_addrinfo_t daihead = NULL;
dns_addrinfo_t dai;
struct addrinfo *aibuf = NULL;
struct addrinfo hints, *ai;
char portstr[21];
int ret;
*r_dai = NULL;
if (r_canonname)
*r_canonname = NULL;
memset (&hints, 0, sizeof hints);
hints.ai_family = want_family;
hints.ai_socktype = want_socktype;
hints.ai_flags = AI_ADDRCONFIG;
if (r_canonname)
hints.ai_flags |= AI_CANONNAME;
if (is_ip_address (name))
hints.ai_flags |= AI_NUMERICHOST;
if (port)