1 /* dns-stuff.c - DNS related code including CERT RR (rfc-4398)
2 * Copyright (C) 2003, 2005, 2006, 2009 Free Software Foundation, Inc.
3 * Copyright (C) 2005, 2006, 2009, 2015. 2016 Werner Koch
5 * This file is part of GnuPG.
7 * This file is free software; you can redistribute it and/or modify
8 * it under the terms of either
10 * - the GNU Lesser General Public License as published by the Free
11 * Software Foundation; either version 3 of the License, or (at
12 * your option) any later version.
16 * - the GNU General Public License as published by the Free
17 * Software Foundation; either version 2 of the License, or (at
18 * your option) any later version.
20 * or both in parallel, as here.
22 * This file is distributed in the hope that it will be useful,
23 * but WITHOUT ANY WARRANTY; without even the implied warranty of
24 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
25 * GNU General Public License for more details.
27 * You should have received a copy of the GNU General Public License
28 * along with this program; if not, see <https://www.gnu.org/licenses/>.
32 #include <sys/types.h>
33 #ifdef HAVE_W32_SYSTEM
34 # define WIN32_LEAN_AND_MEAN
35 # ifdef HAVE_WINSOCK2_H
36 # include <winsock2.h>
39 # include <iphlpapi.h>
41 # if HAVE_SYSTEM_RESOLVER
42 # include <netinet/in.h>
43 # include <arpa/nameser.h>
52 /* William Ahern's DNS library, included as a source copy. */
57 /* dns.c has a dns_p_free but it is not exported. We use our own
58 * wrapper here so that we do not accidentally use xfree which would
59 * be wrong for dns.c allocated data. */
60 #define dns_free(a) free ((a))
63 #ifdef WITHOUT_NPTH /* Give the Makefile a chance to build without Pth. */
70 #include "./dirmngr-err.h"
73 #include "dns-stuff.h"
76 # define my_unprotect() npth_unprotect ()
77 # define my_protect() npth_protect ()
79 # define my_unprotect() do { } while(0)
80 # define my_protect() do { } while(0)
83 /* We allow the use of 0 instead of AF_UNSPEC - check this assumption. */
85 # error AF_UNSPEC does not have the value 0
88 /* Windows does not support the AI_ADDRCONFIG flag - use zero instead. */
90 # define AI_ADDRCONFIG 0
93 /* Not every installation has gotten around to supporting SRVs or
102 /* The standard SOCKS and TOR ports. */
103 #define SOCKS_PORT 1080
104 #define TOR_PORT 9050
105 #define TOR_PORT2 9150 /* (Used by the Tor browser) */
108 /* The default nameserver used in Tor mode. */
109 #define DEFAULT_NAMESERVER "8.8.8.8"
111 /* The default timeout in seconds for libdns requests. */
112 #define DEFAULT_TIMEOUT 30
115 /* Two flags to enable verbose and debug mode. */
116 static int opt_verbose;
117 static int opt_debug;
119 /* The timeout in seconds for libdns requests. */
120 static int opt_timeout;
122 /* If set force the use of the standard resolver. */
123 static int standard_resolver;
125 /* If set use recursive resolver when available. */
126 static int recursive_resolver;
128 /* If set Tor mode shall be used. */
131 /* A string with the nameserver IP address used with Tor.
132 (40 should be sufficient for v6 but we add some extra for a scope.) */
133 static char tor_nameserver[40+20];
135 /* Two strings to hold the credentials presented to Tor. */
136 static char tor_socks_user[30];
137 static char tor_socks_password[20];
141 /* Libdns gobal data. */
144 struct dns_resolv_conf *resolv_conf;
145 struct dns_hosts *hosts;
146 struct dns_hints *hints;
148 struct sockaddr_storage socks_host;
151 /* If this flag is set, libdns shall be reinited for the next use. */
152 static int libdns_reinit_pending;
154 /* The Tor port to be used. */
155 static int libdns_tor_port;
157 #endif /*USE_LIBDNS*/
160 /* Calling this function with YES set to True forces the use of the
161 * standard resolver even if dirmngr has been built with support for
162 * an alternative resolver. */
164 enable_standard_resolver (int yes)
166 standard_resolver = yes;
170 /* Return true if the standard resolver is used. */
172 standard_resolver_p (void)
174 return standard_resolver;
178 /* Calling this function with YES switches libdns into recursive mode.
179 * It has no effect on the standard resolver. */
181 enable_recursive_resolver (int yes)
183 recursive_resolver = yes;
185 libdns_reinit_pending = 1;
190 /* Return true iff the recursive resolver is used. */
192 recursive_resolver_p (void)
195 return !standard_resolver && recursive_resolver;
202 /* Puts this module eternally into Tor mode. When called agained with
203 * NEW_CIRCUIT request a new TOR circuit for the next DNS query. */
205 enable_dns_tormode (int new_circuit)
207 if (!*tor_socks_user || new_circuit)
209 static unsigned int counter;
211 gpgrt_snprintf (tor_socks_user, sizeof tor_socks_user,
212 "dirmngr-%lu", (unsigned long)getpid ());
213 gpgrt_snprintf (tor_socks_password, sizeof tor_socks_password,
221 /* Set verbosity and debug mode for this module. */
223 set_dns_verbose (int verbose, int debug)
225 opt_verbose = verbose;
230 /* Set the timeout for libdns requests to SECONDS. A value of 0 sets
231 * the default timeout and values are capped at 10 minutes. */
233 set_dns_timeout (int seconds)
236 seconds = DEFAULT_TIMEOUT;
237 else if (seconds < 1)
239 else if (seconds > 600)
242 opt_timeout = seconds;
246 /* Change the default IP address of the nameserver to IPADDR. The
247 address needs to be a numerical IP address and will be used for the
248 next DNS query. Note that this is only used in Tor mode. */
250 set_dns_nameserver (const char *ipaddr)
252 strncpy (tor_nameserver, ipaddr? ipaddr : DEFAULT_NAMESERVER,
253 sizeof tor_nameserver -1);
254 tor_nameserver[sizeof tor_nameserver -1] = 0;
256 libdns_reinit_pending = 1;
257 libdns_tor_port = 0; /* Start again with the default port. */
262 /* Free an addressinfo linked list as returned by resolve_dns_name. */
264 free_dns_addrinfo (dns_addrinfo_t ai)
268 dns_addrinfo_t next = ai->next;
275 #ifndef HAVE_W32_SYSTEM
276 /* Return H_ERRNO mapped to a gpg-error code. Will never return 0. */
278 get_h_errno_as_gpg_error (void)
284 case HOST_NOT_FOUND: ec = GPG_ERR_NO_NAME; break;
285 case TRY_AGAIN: ec = GPG_ERR_TRY_LATER; break;
286 case NO_RECOVERY: ec = GPG_ERR_SERVER_FAILED; break;
287 case NO_DATA: ec = GPG_ERR_NO_DATA; break;
288 default: ec = GPG_ERR_UNKNOWN_ERRNO; break;
290 return gpg_error (ec);
292 #endif /*!HAVE_W32_SYSTEM*/
295 map_eai_to_gpg_error (int ec)
301 case EAI_AGAIN: err = gpg_error (GPG_ERR_EAGAIN); break;
302 case EAI_BADFLAGS: err = gpg_error (GPG_ERR_INV_FLAG); break;
303 case EAI_FAIL: err = gpg_error (GPG_ERR_SERVER_FAILED); break;
304 case EAI_MEMORY: err = gpg_error (GPG_ERR_ENOMEM); break;
306 case EAI_NODATA: err = gpg_error (GPG_ERR_NO_DATA); break;
308 case EAI_NONAME: err = gpg_error (GPG_ERR_NO_NAME); break;
309 case EAI_SERVICE: err = gpg_error (GPG_ERR_NOT_SUPPORTED); break;
310 case EAI_FAMILY: err = gpg_error (GPG_ERR_EAFNOSUPPORT); break;
311 case EAI_SOCKTYPE: err = gpg_error (GPG_ERR_ESOCKTNOSUPPORT); break;
312 #ifndef HAVE_W32_SYSTEM
313 # ifdef EAI_ADDRFAMILY
314 case EAI_ADDRFAMILY:err = gpg_error (GPG_ERR_EADDRNOTAVAIL); break;
316 case EAI_SYSTEM: err = gpg_error_from_syserror (); break;
318 default: err = gpg_error (GPG_ERR_UNKNOWN_ERRNO); break;
326 libdns_error_to_gpg_error (int serr)
332 case 0: ec = 0; break;
334 case DNS_ENOBUFS: ec = GPG_ERR_BUFFER_TOO_SHORT; break;
335 case DNS_EILLEGAL: ec = GPG_ERR_INV_OBJ; break;
336 case DNS_EORDER: ec = GPG_ERR_INV_ORDER; break;
337 case DNS_ESECTION: ec = GPG_ERR_DNS_SECTION; break;
338 case DNS_EUNKNOWN: ec = GPG_ERR_DNS_UNKNOWN; break;
339 case DNS_EADDRESS: ec = GPG_ERR_DNS_ADDRESS; break;
340 case DNS_ENOQUERY: ec = GPG_ERR_DNS_NO_QUERY; break;
341 case DNS_ENOANSWER:ec = GPG_ERR_DNS_NO_ANSWER; break;
342 case DNS_EFETCHED: ec = GPG_ERR_ALREADY_FETCHED; break;
343 case DNS_ESERVICE: ec = GPG_ERR_NOT_SUPPORTED; break;
344 case DNS_ENONAME: ec = GPG_ERR_NO_NAME; break;
345 case DNS_EFAIL: ec = GPG_ERR_SERVER_FAILED; break;
346 case DNS_ECONNFIN: ec = GPG_ERR_DNS_CLOSED; break;
347 case DNS_EVERIFY: ec = GPG_ERR_DNS_VERIFY; break;
351 ec = gpg_err_code_from_errno (serr);
353 ec = GPG_ERR_DNS_UNKNOWN;
356 return gpg_error (ec);
358 #endif /*USE_LIBDNS*/
362 /* Initialize libdns. Returns 0 on success; prints a diagnostic and
363 * returns an error code on failure. */
372 if (libdns.resolv_conf)
373 return 0; /* Already initialized. */
375 memset (&ld, 0, sizeof ld);
377 ld.resolv_conf = dns_resconf_open (&derr);
380 err = libdns_error_to_gpg_error (derr);
381 log_error ("failed to allocate DNS resconf object: %s\n",
388 if (!*tor_nameserver)
389 set_dns_nameserver (NULL);
391 if (!libdns_tor_port)
392 libdns_tor_port = TOR_PORT;
394 cfgstr = xtryasprintf ("[%s]:53", tor_nameserver);
396 err = gpg_error_from_syserror ();
398 err = libdns_error_to_gpg_error
399 (dns_resconf_pton (&ld.resolv_conf->nameserver[0], cfgstr));
401 log_error ("failed to set nameserver '%s': %s\n",
402 cfgstr, gpg_strerror (err));
406 ld.resolv_conf->options.tcp = DNS_RESCONF_TCP_SOCKS;
409 cfgstr = xtryasprintf ("[%s]:%d", "127.0.0.1", libdns_tor_port);
411 err = gpg_error_from_syserror ();
413 err = libdns_error_to_gpg_error
414 (dns_resconf_pton (&ld.socks_host, cfgstr));
417 log_error ("failed to set socks server '%s': %s\n",
418 cfgstr, gpg_strerror (err));
424 #ifdef HAVE_W32_SYSTEM
431 ninfo = xtrymalloc (ninfo_len);
434 err = gpg_error_from_syserror ();
438 if (GetNetworkParams (ninfo, &ninfo_len))
440 log_error ("GetNetworkParms failed: %s\n", w32_strerror (-1));
441 err = gpg_error (GPG_ERR_GENERAL);
446 for (idx=0, pip = &(ninfo->DnsServerList);
447 pip && idx < DIM (ld.resolv_conf->nameserver);
451 log_debug ("dns: dnsserver[%d] '%s'\n", idx, pip->IpAddress.String);
452 err = libdns_error_to_gpg_error
453 (dns_resconf_pton (&ld.resolv_conf->nameserver[idx],
454 pip->IpAddress.String));
456 log_error ("failed to set nameserver[%d] '%s': %s\n",
457 idx, pip->IpAddress.String, gpg_strerror (err));
466 fname = "/etc/resolv.conf";
467 err = libdns_error_to_gpg_error
468 (dns_resconf_loadpath (ld.resolv_conf, fname));
471 log_error ("failed to load '%s': %s\n", fname, gpg_strerror (err));
475 fname = "/etc/nsswitch.conf";
476 err = libdns_error_to_gpg_error
477 (dns_nssconf_loadpath (ld.resolv_conf, fname));
480 log_error ("failed to load '%s': %s\n", fname, gpg_strerror (err));
487 ld.hosts = dns_hosts_open (&derr);
490 log_error ("failed to load hosts file: %s\n", gpg_strerror (err));
491 err = libdns_error_to_gpg_error (derr);
495 /* dns_hints_local for stub mode, dns_hints_root for recursive. */
496 ld.hints = (recursive_resolver
497 ? dns_hints_root (ld.resolv_conf, &derr)
498 : dns_hints_local (ld.resolv_conf, &derr));
501 log_error ("failed to load DNS hints: %s\n", gpg_strerror (err));
502 err = libdns_error_to_gpg_error (derr);
506 /* All fine. Make the data global. */
510 log_debug ("dns: libdns initialized%s\n", tor_mode?" (tor mode)":"");
516 #endif /*USE_LIBDNS*/
520 /* Deinitialize libdns. */
526 if (!libdns.resolv_conf)
527 return; /* Not initialized. */
530 memset (&libdns, 0, sizeof libdns);
531 dns_hints_close (ld.hints);
532 dns_hosts_close (ld.hosts);
533 dns_resconf_close (ld.resolv_conf);
535 #endif /*USE_LIBDNS*/
538 /* SIGHUP action handler for this module. With FORCE set objects are
539 * all immediately released. */
541 reload_dns_stuff (int force)
547 libdns_reinit_pending = 0;
551 libdns_reinit_pending = 1;
552 libdns_tor_port = 0; /* Start again with the default port. */
562 * Initialize libdns if needed and open a dns_resolver context.
563 * Returns 0 on success and stores the new context at R_RES. On
564 * failure an error code is returned and NULL stored at R_RES.
567 libdns_res_open (struct dns_resolver **r_res)
570 struct dns_resolver *res;
575 if (libdns_reinit_pending)
577 libdns_reinit_pending = 0;
581 err = libdns_init ();
588 res = dns_res_open (libdns.resolv_conf, libdns.hosts, libdns.hints, NULL,
589 dns_opts (.socks_host = &libdns.socks_host,
590 .socks_user = tor_socks_user,
591 .socks_password = tor_socks_password ),
594 return libdns_error_to_gpg_error (derr);
599 #endif /*USE_LIBDNS*/
603 /* Helper to test whether we need to try again after having switched
606 libdns_switch_port_p (gpg_error_t err)
608 if (tor_mode && gpg_err_code (err) == GPG_ERR_ECONNREFUSED
609 && libdns_tor_port == TOR_PORT)
611 /* Switch port and try again. */
613 log_debug ("dns: switching from SOCKS port %d to %d\n",
614 TOR_PORT, TOR_PORT2);
615 libdns_tor_port = TOR_PORT2;
616 libdns_reinit_pending = 1;
621 #endif /*USE_LIBDNS*/
625 /* Wrapper around dns_res_submit. */
627 libdns_res_submit (struct dns_resolver *res, const char *qname,
628 enum dns_type qtype, enum dns_class qclass)
630 return libdns_error_to_gpg_error (dns_res_submit (res, qname, qtype, qclass));
632 #endif /*USE_LIBDNS*/
636 /* Standard event handling loop. */
638 libdns_res_wait (struct dns_resolver *res)
642 while ((err = libdns_error_to_gpg_error (dns_res_check (res)))
643 && gpg_err_code (err) == GPG_ERR_EAGAIN)
645 if (dns_res_elapsed (res) > opt_timeout)
647 err = gpg_error (GPG_ERR_DNS_TIMEOUT);
652 dns_res_poll (res, 1);
658 #endif /*USE_LIBDNS*/
663 resolve_name_libdns (const char *name, unsigned short port,
664 int want_family, int want_socktype,
665 dns_addrinfo_t *r_dai, char **r_canonname)
668 dns_addrinfo_t daihead = NULL;
670 struct dns_resolver *res = NULL;
671 struct dns_addrinfo *ai = NULL;
672 struct addrinfo hints;
673 struct addrinfo *ent;
675 char *portstr = NULL;
682 memset (&hints, 0, sizeof hints);
683 hints.ai_family = want_family;
684 hints.ai_socktype = want_socktype;
685 hints.ai_flags = AI_ADDRCONFIG;
687 hints.ai_flags |= AI_CANONNAME;
691 snprintf (portstr_, sizeof portstr_, "%hu", port);
695 err = libdns_res_open (&res);
699 ai = dns_ai_open (name, portstr, 0, &hints, res, &derr);
702 err = libdns_error_to_gpg_error (derr);
706 /* Loop over all records. */
709 err = libdns_error_to_gpg_error (dns_ai_nextent (&ent, ai));
710 if (gpg_err_code (err) == GPG_ERR_ENOENT)
713 err = 0; /* We got some results, we're good. */
716 if (gpg_err_code (err) == GPG_ERR_EAGAIN)
718 if (dns_ai_elapsed (ai) > opt_timeout)
720 err = gpg_error (GPG_ERR_DNS_TIMEOUT);
732 if (r_canonname && ! *r_canonname && ent && ent->ai_canonname)
734 *r_canonname = xtrystrdup (ent->ai_canonname);
737 err = gpg_error_from_syserror ();
740 /* Libdns appends the root zone part which is problematic
741 * for most other functions - strip it. */
742 if (**r_canonname && (*r_canonname)[strlen (*r_canonname)-1] == '.')
743 (*r_canonname)[strlen (*r_canonname)-1] = 0;
746 dai = xtrymalloc (sizeof *dai + ent->ai_addrlen -1);
749 err = gpg_error_from_syserror ();
753 dai->family = ent->ai_family;
754 dai->socktype = ent->ai_socktype;
755 dai->protocol = ent->ai_protocol;
756 dai->addrlen = ent->ai_addrlen;
757 memcpy (dai->addr, ent->ai_addr, ent->ai_addrlen);
772 xfree (*r_canonname);
775 free_dns_addrinfo (daihead);
782 #endif /*USE_LIBDNS*/
785 /* Resolve a name using the standard system function. */
787 resolve_name_standard (const char *name, unsigned short port,
788 int want_family, int want_socktype,
789 dns_addrinfo_t *r_dai, char **r_canonname)
792 dns_addrinfo_t daihead = NULL;
794 struct addrinfo *aibuf = NULL;
795 struct addrinfo hints, *ai;
803 memset (&hints, 0, sizeof hints);
804 hints.ai_family = want_family;
805 hints.ai_socktype = want_socktype;
806 hints.ai_flags = AI_ADDRCONFIG;
808 hints.ai_flags |= AI_CANONNAME;
811 snprintf (portstr, sizeof portstr, "%hu", port);
815 /* We can't use the the AI_IDN flag because that does the conversion
816 using the current locale. However, GnuPG always used UTF-8. To
817 support IDN we would need to make use of the libidn API. */
818 ret = getaddrinfo (name, *portstr? portstr : NULL, &hints, &aibuf);
822 err = map_eai_to_gpg_error (ret);
823 if (gpg_err_code (err) == GPG_ERR_NO_NAME)
825 /* There seems to be a bug in the glibc getaddrinfo function
826 if the CNAME points to a long list of A and AAAA records
827 in which case the function return NO_NAME. Let's do the
828 CNAME redirection again. */
831 if (get_dns_cname (name, &cname))
832 goto leave; /* Still no success. */
834 ret = getaddrinfo (cname, *portstr? portstr : NULL, &hints, &aibuf);
839 err = map_eai_to_gpg_error (ret);
842 err = 0; /* Yep, now it worked. */
848 if (r_canonname && aibuf && aibuf->ai_canonname)
850 *r_canonname = xtrystrdup (aibuf->ai_canonname);
853 err = gpg_error_from_syserror ();
858 for (ai = aibuf; ai; ai = ai->ai_next)
860 if (ai->ai_family != AF_INET6 && ai->ai_family != AF_INET)
863 dai = xtrymalloc (sizeof *dai + ai->ai_addrlen - 1);
864 dai->family = ai->ai_family;
865 dai->socktype = ai->ai_socktype;
866 dai->protocol = ai->ai_protocol;
867 dai->addrlen = ai->ai_addrlen;
868 memcpy (dai->addr, ai->ai_addr, ai->ai_addrlen);
875 freeaddrinfo (aibuf);
880 xfree (*r_canonname);
883 free_dns_addrinfo (daihead);
891 /* Resolve an address using the standard system function. */
893 resolve_addr_standard (const struct sockaddr *addr, int addrlen,
894 unsigned int flags, char **r_name)
904 buffer = xtrymalloc (buflen + 2 + 1);
906 return gpg_error_from_syserror ();
908 if ((flags & DNS_NUMERICHOST) || tor_mode)
911 ec = getnameinfo (addr, addrlen, buffer, buflen, NULL, 0, NI_NAMEREQD);
913 if (!ec && *buffer == '[')
914 ec = EAI_FAIL; /* A name may never start with a bracket. */
915 else if (ec == EAI_NONAME)
918 if (addr->sa_family == AF_INET6 && (flags & DNS_WITHBRACKET))
923 ec = getnameinfo (addr, addrlen, p, buflen, NULL, 0, NI_NUMERICHOST);
924 if (!ec && addr->sa_family == AF_INET6 && (flags & DNS_WITHBRACKET))
925 strcat (buffer, "]");
929 err = map_eai_to_gpg_error (ec);
932 p = xtryrealloc (buffer, strlen (buffer)+1);
934 err = gpg_error_from_syserror ();
951 /* This a wrapper around getaddrinfo with slightly different semantics.
952 NAME is the name to resolve.
953 PORT is the requested port or 0.
954 WANT_FAMILY is either 0 (AF_UNSPEC), AF_INET6, or AF_INET4.
955 WANT_SOCKETTYPE is either SOCK_STREAM or SOCK_DGRAM.
957 On success the result is stored in a linked list with the head
958 stored at the address R_AI; the caller must call gpg_addrinfo_free
959 on this. If R_CANONNAME is not NULL the official name of the host
960 is stored there as a malloced string; if that name is not available
963 resolve_dns_name (const char *name, unsigned short port,
964 int want_family, int want_socktype,
965 dns_addrinfo_t *r_ai, char **r_canonname)
970 if (!standard_resolver)
972 err = resolve_name_libdns (name, port, want_family, want_socktype,
974 if (err && libdns_switch_port_p (err))
975 err = resolve_name_libdns (name, port, want_family, want_socktype,
979 #endif /*USE_LIBDNS*/
980 err = resolve_name_standard (name, port, want_family, want_socktype,
983 log_debug ("dns: resolve_dns_name(%s): %s\n", name, gpg_strerror (err));
989 resolve_dns_addr (const struct sockaddr *addr, int addrlen,
990 unsigned int flags, char **r_name)
992 return resolve_addr_standard (addr, addrlen, flags, r_name);
996 /* Check whether NAME is an IP address. Returns true if it is either
997 an IPv6 or IPv4 numerical address. */
999 is_ip_address (const char *name)
1002 int ndots, dblcol, n;
1005 return 1; /* yes: A legal DNS name may not contain this character;
1006 this mut be bracketed v6 address. */
1008 return 0; /* No. A leading dot is not a valid IP address. */
1010 /* Check whether this is a v6 address. */
1011 ndots = n = dblcol = 0;
1012 for (s=name; *s; s++)
1021 return 0; /* No: Only one "::" allowed. */
1030 else if (!strchr ("0123456789abcdefABCDEF", *s))
1031 return 0; /* No: Not a hex digit. */
1033 return 0; /* To many digits in a group. */
1036 return 0; /* No: Too many colons. */
1038 return 1; /* Yes: At least 2 colons indicate an v6 address. */
1041 /* Check whether it is legacy IP address. */
1043 for (s=name; *s; s++)
1048 return 0; /* No: Douple dot. */
1049 if (atoi (s+1) > 255)
1050 return 0; /* No: Ipv4 byte value too large. */
1054 else if (!strchr ("0123456789", *s))
1055 return 0; /* No: Not a digit. */
1057 return 0; /* No: More than 3 digits. */
1059 return !!(ndots == 3);
1063 /* Return true if NAME is an onion address. */
1065 is_onion_address (const char *name)
1069 len = name? strlen (name) : 0;
1070 if (len < 8 || strcmp (name + len - 6, ".onion"))
1072 /* Note that we require at least 2 characters before the suffix. */
1073 return 1; /* Yes. */
1077 /* libdns version of get_dns_cert. */
1080 get_dns_cert_libdns (const char *name, int want_certtype,
1081 void **r_key, size_t *r_keylen,
1082 unsigned char **r_fpr, size_t *r_fprlen, char **r_url)
1085 struct dns_resolver *res = NULL;
1086 struct dns_packet *ans = NULL;
1088 struct dns_rr_i rri;
1089 char host[DNS_D_MAXNAME + 1];
1093 /* Gte the query type from WANT_CERTTYPE (which in general indicates
1094 * the subtype we want). */
1095 qtype = (want_certtype < DNS_CERTTYPE_RRBASE
1097 : (want_certtype - DNS_CERTTYPE_RRBASE));
1100 err = libdns_res_open (&res);
1104 if (dns_d_anchor (host, sizeof host, name, strlen (name)) >= sizeof host)
1106 err = gpg_error (GPG_ERR_ENAMETOOLONG);
1110 err = libdns_res_submit (res, name, qtype, DNS_C_IN);
1114 err = libdns_res_wait (res);
1118 ans = dns_res_fetch (res, &derr);
1121 err = libdns_error_to_gpg_error (derr);
1125 /* Check the rcode. */
1126 switch (dns_p_rcode (ans))
1128 case DNS_RC_NOERROR: break;
1129 case DNS_RC_NXDOMAIN: err = gpg_error (GPG_ERR_NO_NAME); break;
1130 default: err = GPG_ERR_SERVER_FAILED; break;
1135 memset (&rri, 0, sizeof rri);
1136 dns_rr_i_init (&rri, ans);
1137 rri.section = DNS_S_ALL & ~DNS_S_QD;
1141 err = gpg_error (GPG_ERR_NOT_FOUND);
1142 while (dns_rr_grep (&rr, 1, &rri, ans, &derr))
1144 unsigned char *rp = ans->data + rr.rd.p;
1145 unsigned short len = rr.rd.len;
1150 /* Definitely too short - skip. */
1152 else if (want_certtype >= DNS_CERTTYPE_RRBASE
1153 && rr.type == (want_certtype - DNS_CERTTYPE_RRBASE)
1156 *r_key = xtrymalloc (len);
1158 err = gpg_error_from_syserror ();
1161 memcpy (*r_key, rp, len);
1167 else if (want_certtype >= DNS_CERTTYPE_RRBASE)
1169 /* We did not found the requested RR - skip. */
1171 else if (rr.type == T_CERT && len > 5)
1173 /* We got a CERT type. */
1174 subtype = buf16_to_u16 (rp);
1177 /* Skip the CERT key tag and algo which we don't need. */
1180 if (want_certtype && want_certtype != subtype)
1181 ; /* Not the requested subtype - skip. */
1182 else if (subtype == DNS_CERTTYPE_PGP && len && r_key && r_keylen)
1185 *r_key = xtrymalloc (len);
1187 err = gpg_error_from_syserror ();
1190 memcpy (*r_key, rp, len);
1196 else if (subtype == DNS_CERTTYPE_IPGP
1197 && len && len < 1023 && len >= rp[0] + 1)
1203 *r_fpr = xtrymalloc (*r_fprlen);
1206 err = gpg_error_from_syserror ();
1209 memcpy (*r_fpr, rp+1, *r_fprlen);
1214 if (len > *r_fprlen + 1)
1216 *r_url = xtrymalloc (len - (*r_fprlen + 1) + 1);
1219 err = gpg_error_from_syserror ();
1224 memcpy (*r_url, rp + *r_fprlen + 1, len - (*r_fprlen + 1));
1225 (*r_url)[len - (*r_fprlen + 1)] = 0;
1235 /* Unknown subtype or record too short - skip. */
1240 /* Not a requested type - skip. */
1246 dns_res_close (res);
1249 #endif /*USE_LIBDNS*/
1252 /* Standard resolver version of get_dns_cert. */
1254 get_dns_cert_standard (const char *name, int want_certtype,
1255 void **r_key, size_t *r_keylen,
1256 unsigned char **r_fpr, size_t *r_fprlen, char **r_url)
1258 #ifdef HAVE_SYSTEM_RESOLVER
1260 unsigned char *answer;
1264 /* Allocate a 64k buffer which is the limit for an DNS response. */
1265 answer = xtrymalloc (65536);
1267 return gpg_error_from_syserror ();
1269 err = gpg_error (GPG_ERR_NOT_FOUND);
1270 r = res_query (name, C_IN,
1271 (want_certtype < DNS_CERTTYPE_RRBASE
1273 : (want_certtype - DNS_CERTTYPE_RRBASE)),
1275 /* Not too big, not too small, no errors and at least 1 answer. */
1276 if (r >= sizeof (HEADER) && r <= 65536
1277 && (((HEADER *)(void *) answer)->rcode) == NOERROR
1278 && (count = ntohs (((HEADER *)(void *) answer)->ancount)))
1281 unsigned char *pt, *emsg;
1285 pt = &answer[sizeof (HEADER)];
1287 /* Skip over the query */
1289 rc = dn_skipname (pt, emsg);
1292 err = gpg_error (GPG_ERR_INV_OBJ);
1295 pt += rc + QFIXEDSZ;
1297 /* There are several possible response types for a CERT request.
1298 We're interested in the PGP (a key) and IPGP (a URI) types.
1299 Skip all others. TODO: A key is better than a URI since
1300 we've gone through all this bother to fetch it, so favor that
1301 if we have both PGP and IPGP? */
1303 while (count-- > 0 && pt < emsg)
1305 u16 type, class, dlen, ctype;
1307 rc = dn_skipname (pt, emsg); /* the name we just queried for */
1310 err = gpg_error (GPG_ERR_INV_OBJ);
1316 /* Truncated message? 15 bytes takes us to the point where
1317 we start looking at the ctype. */
1318 if ((emsg - pt) < 15)
1321 type = buf16_to_u16 (pt);
1324 class = buf16_to_u16 (pt);
1334 dlen = buf16_to_u16 (pt);
1337 /* Check the type and parse. */
1338 if (want_certtype >= DNS_CERTTYPE_RRBASE
1339 && type == (want_certtype - DNS_CERTTYPE_RRBASE)
1342 *r_key = xtrymalloc (dlen);
1344 err = gpg_error_from_syserror ();
1347 memcpy (*r_key, pt, dlen);
1353 else if (want_certtype >= DNS_CERTTYPE_RRBASE)
1355 /* We did not found the requested RR. */
1358 else if (type == T_CERT)
1360 /* We got a CERT type. */
1361 ctype = buf16_to_u16 (pt);
1364 /* Skip the CERT key tag and algo which we don't need. */
1369 /* 15 bytes takes us to here */
1370 if (want_certtype && want_certtype != ctype)
1371 ; /* Not of the requested certtype. */
1372 else if (ctype == DNS_CERTTYPE_PGP && dlen && r_key && r_keylen)
1375 *r_key = xtrymalloc (dlen);
1377 err = gpg_error_from_syserror ();
1380 memcpy (*r_key, pt, dlen);
1386 else if (ctype == DNS_CERTTYPE_IPGP
1387 && dlen && dlen < 1023 && dlen >= pt[0] + 1)
1393 *r_fpr = xtrymalloc (*r_fprlen);
1396 err = gpg_error_from_syserror ();
1399 memcpy (*r_fpr, &pt[1], *r_fprlen);
1404 if (dlen > *r_fprlen + 1)
1406 *r_url = xtrymalloc (dlen - (*r_fprlen + 1) + 1);
1409 err = gpg_error_from_syserror ();
1414 memcpy (*r_url, &pt[*r_fprlen + 1],
1415 dlen - (*r_fprlen + 1));
1416 (*r_url)[dlen - (*r_fprlen + 1)] = '\0';
1425 /* No subtype matches, so continue with the next answer. */
1430 /* Not a requested type - might be a CNAME. Try next item. */
1440 #else /*!HAVE_SYSTEM_RESOLVER*/
1443 (void)want_certtype;
1449 return gpg_error (GPG_ERR_NOT_SUPPORTED);
1451 #endif /*!HAVE_SYSTEM_RESOLVER*/
1455 /* Returns 0 on success or an error code. If a PGP CERT record was
1456 found, the malloced data is returned at (R_KEY, R_KEYLEN) and
1457 the other return parameters are set to NULL/0. If an IPGP CERT
1458 record was found the fingerprint is stored as an allocated block at
1459 R_FPR and its length at R_FPRLEN; an URL is is allocated as a
1460 string and returned at R_URL. If WANT_CERTTYPE is 0 this function
1461 returns the first CERT found with a supported type; it is expected
1462 that only one CERT record is used. If WANT_CERTTYPE is one of the
1463 supported certtypes only records with this certtype are considered
1464 and the first found is returned. (R_KEY,R_KEYLEN) are optional. */
1466 get_dns_cert (const char *name, int want_certtype,
1467 void **r_key, size_t *r_keylen,
1468 unsigned char **r_fpr, size_t *r_fprlen, char **r_url)
1481 if (!standard_resolver)
1483 err = get_dns_cert_libdns (name, want_certtype, r_key, r_keylen,
1484 r_fpr, r_fprlen, r_url);
1485 if (err && libdns_switch_port_p (err))
1486 err = get_dns_cert_libdns (name, want_certtype, r_key, r_keylen,
1487 r_fpr, r_fprlen, r_url);
1490 #endif /*USE_LIBDNS*/
1491 err = get_dns_cert_standard (name, want_certtype, r_key, r_keylen,
1492 r_fpr, r_fprlen, r_url);
1495 log_debug ("dns: get_dns_cert(%s): %s\n", name, gpg_strerror (err));
1501 priosort(const void *a,const void *b)
1503 const struct srventry *sa=a,*sb=b;
1504 if(sa->priority>sb->priority)
1506 else if(sa->priority<sb->priority)
1513 /* Libdns based helper for getsrv. Note that it is expected that NULL
1514 * is stored at the address of LIST and 0 is stored at the address of
1518 getsrv_libdns (const char *name, struct srventry **list, unsigned int *r_count)
1521 struct dns_resolver *res = NULL;
1522 struct dns_packet *ans = NULL;
1524 struct dns_rr_i rri;
1525 char host[DNS_D_MAXNAME + 1];
1527 unsigned int srvcount = 0;
1529 err = libdns_res_open (&res);
1533 if (dns_d_anchor (host, sizeof host, name, strlen (name)) >= sizeof host)
1535 err = gpg_error (GPG_ERR_ENAMETOOLONG);
1539 err = libdns_res_submit (res, name, DNS_T_SRV, DNS_C_IN);
1543 err = libdns_res_wait (res);
1547 ans = dns_res_fetch (res, &derr);
1550 err = libdns_error_to_gpg_error (derr);
1554 /* Check the rcode. */
1555 switch (dns_p_rcode (ans))
1557 case DNS_RC_NOERROR: break;
1558 case DNS_RC_NXDOMAIN: err = gpg_error (GPG_ERR_NO_NAME); break;
1559 default: err = GPG_ERR_SERVER_FAILED; break;
1564 memset (&rri, 0, sizeof rri);
1565 dns_rr_i_init (&rri, ans);
1566 rri.section = DNS_S_ALL & ~DNS_S_QD;
1568 rri.type = DNS_T_SRV;
1570 while (dns_rr_grep (&rr, 1, &rri, ans, &derr))
1572 struct dns_srv dsrv;
1573 struct srventry *srv;
1574 struct srventry *newlist;
1576 err = libdns_error_to_gpg_error (dns_srv_parse(&dsrv, &rr, ans));
1580 newlist = xtryrealloc (*list, (srvcount+1)*sizeof(struct srventry));
1583 err = gpg_error_from_syserror ();
1587 memset (&(*list)[srvcount], 0, sizeof(struct srventry));
1588 srv = &(*list)[srvcount];
1590 srv->priority = dsrv.priority;
1591 srv->weight = dsrv.weight;
1592 srv->port = dsrv.port;
1593 mem2str (srv->target, dsrv.target, sizeof srv->target);
1596 *r_count = srvcount;
1605 dns_res_close (res);
1608 #endif /*USE_LIBDNS*/
1611 /* Standard resolver based helper for getsrv. Note that it is
1612 * expected that NULL is stored at the address of LIST and 0 is stored
1613 * at the address of R_COUNT. */
1615 getsrv_standard (const char *name,
1616 struct srventry **list, unsigned int *r_count)
1618 #ifdef HAVE_SYSTEM_RESOLVER
1620 unsigned char ans[2048];
1623 unsigned char *answer = res.ans;
1624 HEADER *header = res.header;
1625 unsigned char *pt, *emsg;
1628 unsigned int srvcount = 0;
1631 /* Do not allow a query using the standard resolver in Tor mode. */
1633 return gpg_error (GPG_ERR_NOT_ENABLED);
1636 r = res_query (name, C_IN, T_SRV, answer, sizeof res.ans);
1639 return get_h_errno_as_gpg_error ();
1640 if (r < sizeof (HEADER))
1641 return gpg_error (GPG_ERR_SERVER_FAILED);
1642 if (r > sizeof res.ans)
1643 return gpg_error (GPG_ERR_SYSTEM_BUG);
1644 if (header->rcode != NOERROR || !(count=ntohs (header->ancount)))
1645 return gpg_error (GPG_ERR_NO_NAME); /* Error or no record found. */
1648 pt = &answer[sizeof(HEADER)];
1650 /* Skip over the query */
1651 rc = dn_skipname (pt, emsg);
1655 pt += rc + QFIXEDSZ;
1657 while (count-- > 0 && pt < emsg)
1659 struct srventry *srv;
1661 struct srventry *newlist;
1663 newlist = xtryrealloc (*list, (srvcount+1)*sizeof(struct srventry));
1667 memset (&(*list)[srvcount], 0, sizeof(struct srventry));
1668 srv = &(*list)[srvcount];
1671 rc = dn_skipname (pt, emsg); /* The name we just queried for. */
1676 /* Truncated message? */
1680 type = buf16_to_u16 (pt);
1682 /* We asked for SRV and got something else !? */
1686 class = buf16_to_u16 (pt);
1688 /* We asked for IN and got something else !? */
1693 dlen = buf16_to_u16 (pt);
1696 srv->priority = buf16_to_ushort (pt);
1698 srv->weight = buf16_to_ushort (pt);
1700 srv->port = buf16_to_ushort (pt);
1703 /* Get the name. 2782 doesn't allow name compression, but
1704 * dn_expand still works to pull the name out of the packet. */
1705 rc = dn_expand (answer, emsg, pt, srv->target, sizeof srv->target);
1706 if (rc == 1 && srv->target[0] == 0) /* "." */
1715 /* Corrupt packet? */
1720 *r_count = srvcount;
1726 return gpg_error (GPG_ERR_GENERAL);
1728 #else /*!HAVE_SYSTEM_RESOLVER*/
1733 return gpg_error (GPG_ERR_NOT_SUPPORTED);
1735 #endif /*!HAVE_SYSTEM_RESOLVER*/
1739 /* Note that we do not return NONAME but simply store 0 at R_COUNT. */
1741 get_dns_srv (const char *name, struct srventry **list, unsigned int *r_count)
1744 unsigned int srvcount;
1751 if (!standard_resolver)
1753 err = getsrv_libdns (name, list, &srvcount);
1754 if (err && libdns_switch_port_p (err))
1755 err = getsrv_libdns (name, list, &srvcount);
1758 #endif /*USE_LIBDNS*/
1759 err = getsrv_standard (name, list, &srvcount);
1763 if (gpg_err_code (err) == GPG_ERR_NO_NAME)
1768 /* Now we have an array of all the srv records. */
1770 /* Order by priority */
1771 qsort(*list,srvcount,sizeof(struct srventry),priosort);
1773 /* For each priority, move the zero-weighted items first. */
1774 for (i=0; i < srvcount; i++)
1778 for (j=i;j < srvcount && (*list)[i].priority == (*list)[j].priority; j++)
1780 if((*list)[j].weight==0)
1785 struct srventry temp;
1787 memcpy (&temp,&(*list)[j],sizeof(struct srventry));
1788 memcpy (&(*list)[j],&(*list)[i],sizeof(struct srventry));
1789 memcpy (&(*list)[i],&temp,sizeof(struct srventry));
1797 /* Run the RFC-2782 weighting algorithm. We don't need very high
1798 quality randomness for this, so regular libc srand/rand is
1806 srand (time (NULL)*getpid());
1810 for (i=0; i < srvcount; i++)
1813 float prio_count=0,chose;
1815 for (j=i; j < srvcount && (*list)[i].priority == (*list)[j].priority; j++)
1817 prio_count+=(*list)[j].weight;
1818 (*list)[j].run_count=prio_count;
1821 chose=prio_count*rand()/RAND_MAX;
1823 for (j=i;j<srvcount && (*list)[i].priority==(*list)[j].priority;j++)
1825 if (chose<=(*list)[j].run_count)
1830 struct srventry temp;
1832 memcpy(&temp,&(*list)[j],sizeof(struct srventry));
1833 memcpy(&(*list)[j],&(*list)[i],sizeof(struct srventry));
1834 memcpy(&(*list)[i],&temp,sizeof(struct srventry));
1845 log_debug ("dns: getsrv(%s): %s\n", name, gpg_strerror (err));
1847 log_debug ("dns: getsrv(%s) -> %u records\n", name, srvcount);
1850 *r_count = srvcount;
1857 /* libdns version of get_dns_cname. */
1859 get_dns_cname_libdns (const char *name, char **r_cname)
1862 struct dns_resolver *res;
1863 struct dns_packet *ans = NULL;
1864 struct dns_cname cname;
1867 err = libdns_res_open (&res);
1871 err = libdns_res_submit (res, name, DNS_T_CNAME, DNS_C_IN);
1875 err = libdns_res_wait (res);
1879 ans = dns_res_fetch (res, &derr);
1882 err = libdns_error_to_gpg_error (derr);
1886 /* Check the rcode. */
1887 switch (dns_p_rcode (ans))
1889 case DNS_RC_NOERROR: break;
1890 case DNS_RC_NXDOMAIN: err = gpg_error (GPG_ERR_NO_NAME); break;
1891 default: err = GPG_ERR_SERVER_FAILED; break;
1896 /* Parse the result into CNAME. */
1897 err = libdns_error_to_gpg_error (dns_p_study (ans));
1901 if (!dns_d_cname (&cname, sizeof cname, name, strlen (name), ans, &derr))
1903 err = libdns_error_to_gpg_error (derr);
1908 *r_cname = xtrystrdup (cname.host);
1910 err = gpg_error_from_syserror ();
1913 /* Libdns appends the root zone part which is problematic
1914 * for most other functions - strip it. */
1915 if (**r_cname && (*r_cname)[strlen (*r_cname)-1] == '.')
1916 (*r_cname)[strlen (*r_cname)-1] = 0;
1921 dns_res_close (res);
1924 #endif /*USE_LIBDNS*/
1927 /* Standard resolver version of get_dns_cname. */
1929 get_dns_cname_standard (const char *name, char **r_cname)
1931 #ifdef HAVE_SYSTEM_RESOLVER
1935 unsigned char ans[2048];
1938 unsigned char *answer = res.ans;
1939 HEADER *header = res.header;
1940 unsigned char *pt, *emsg;
1943 int cnamesize = 1025;
1946 /* Do not allow a query using the standard resolver in Tor mode. */
1951 r = res_query (name, C_IN, T_CERT, answer, sizeof res.ans);
1954 return get_h_errno_as_gpg_error ();
1955 if (r < sizeof (HEADER))
1956 return gpg_error (GPG_ERR_SERVER_FAILED);
1957 if (r > sizeof res.ans)
1958 return gpg_error (GPG_ERR_SYSTEM_BUG);
1959 if (header->rcode != NOERROR || !(count=ntohs (header->ancount)))
1960 return gpg_error (GPG_ERR_NO_NAME); /* Error or no record found. */
1962 return gpg_error (GPG_ERR_SERVER_FAILED);
1965 pt = &answer[sizeof(HEADER)];
1966 rc = dn_skipname (pt, emsg);
1968 return gpg_error (GPG_ERR_SERVER_FAILED);
1970 pt += rc + QFIXEDSZ;
1972 return gpg_error (GPG_ERR_SERVER_FAILED);
1974 rc = dn_skipname (pt, emsg);
1976 return gpg_error (GPG_ERR_SERVER_FAILED);
1977 pt += rc + 2 + 2 + 4;
1979 return gpg_error (GPG_ERR_SERVER_FAILED);
1980 pt += 2; /* Skip rdlen */
1982 cname = xtrymalloc (cnamesize);
1984 return gpg_error_from_syserror ();
1986 rc = dn_expand (answer, emsg, pt, cname, cnamesize -1);
1990 return gpg_error (GPG_ERR_SERVER_FAILED);
1992 *r_cname = xtryrealloc (cname, strlen (cname)+1);
1995 err = gpg_error_from_syserror ();
2001 #else /*!HAVE_SYSTEM_RESOLVER*/
2005 return gpg_error (GPG_ERR_NOT_IMPLEMENTED);
2007 #endif /*!HAVE_SYSTEM_RESOLVER*/
2012 get_dns_cname (const char *name, char **r_cname)
2019 if (!standard_resolver)
2021 err = get_dns_cname_libdns (name, r_cname);
2022 if (err && libdns_switch_port_p (err))
2023 err = get_dns_cname_libdns (name, r_cname);
2026 #endif /*USE_LIBDNS*/
2028 err = get_dns_cname_standard (name, r_cname);
2030 log_debug ("get_dns_cname(%s)%s%s\n", name,
2031 err ? ": " : " -> ",
2032 err ? gpg_strerror (err) : *r_cname);