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;
184 libdns_reinit_pending = 1;
188 /* Return true iff the recursive resolver is used. */
190 recursive_resolver_p (void)
193 return !standard_resolver && recursive_resolver;
200 /* Sets the module in Tor mode. Returns 0 is this is possible or an
203 enable_dns_tormode (int new_circuit)
205 if (!*tor_socks_user || new_circuit)
207 static unsigned int counter;
209 gpgrt_snprintf (tor_socks_user, sizeof tor_socks_user,
210 "dirmngr-%lu", (unsigned long)getpid ());
211 gpgrt_snprintf (tor_socks_password, sizeof tor_socks_password,
220 /* Set verbosity and debug mode for this module. */
222 set_dns_verbose (int verbose, int debug)
224 opt_verbose = verbose;
229 /* Set the timeout for libdns requests to SECONDS. A value of 0 sets
230 * the default timeout and values are capped at 10 minutes. */
232 set_dns_timeout (int seconds)
235 seconds = DEFAULT_TIMEOUT;
236 else if (seconds < 1)
238 else if (seconds > 600)
241 opt_timeout = seconds;
245 /* Change the default IP address of the nameserver to IPADDR. The
246 address needs to be a numerical IP address and will be used for the
247 next DNS query. Note that this is only used in Tor mode. */
249 set_dns_nameserver (const char *ipaddr)
251 strncpy (tor_nameserver, ipaddr? ipaddr : DEFAULT_NAMESERVER,
252 sizeof tor_nameserver -1);
253 tor_nameserver[sizeof tor_nameserver -1] = 0;
254 libdns_reinit_pending = 1;
255 libdns_tor_port = 0; /* Start again with the default port. */
259 /* Free an addressinfo linked list as returned by resolve_dns_name. */
261 free_dns_addrinfo (dns_addrinfo_t ai)
265 dns_addrinfo_t next = ai->next;
272 #ifndef HAVE_W32_SYSTEM
273 /* Return H_ERRNO mapped to a gpg-error code. Will never return 0. */
275 get_h_errno_as_gpg_error (void)
281 case HOST_NOT_FOUND: ec = GPG_ERR_UNKNOWN_HOST; break;
282 case TRY_AGAIN: ec = GPG_ERR_TRY_LATER; break;
283 case NO_RECOVERY: ec = GPG_ERR_SERVER_FAILED; break;
284 case NO_DATA: ec = GPG_ERR_NO_DATA; break;
285 default: ec = GPG_ERR_UNKNOWN_ERRNO; break;
287 return gpg_error (ec);
289 #endif /*!HAVE_W32_SYSTEM*/
292 map_eai_to_gpg_error (int ec)
298 case EAI_AGAIN: err = gpg_error (GPG_ERR_EAGAIN); break;
299 case EAI_BADFLAGS: err = gpg_error (GPG_ERR_INV_FLAG); break;
300 case EAI_FAIL: err = gpg_error (GPG_ERR_SERVER_FAILED); break;
301 case EAI_MEMORY: err = gpg_error (GPG_ERR_ENOMEM); break;
303 case EAI_NODATA: err = gpg_error (GPG_ERR_NO_DATA); break;
305 case EAI_NONAME: err = gpg_error (GPG_ERR_NO_NAME); break;
306 case EAI_SERVICE: err = gpg_error (GPG_ERR_NOT_SUPPORTED); break;
307 case EAI_FAMILY: err = gpg_error (GPG_ERR_EAFNOSUPPORT); break;
308 case EAI_SOCKTYPE: err = gpg_error (GPG_ERR_ESOCKTNOSUPPORT); break;
309 #ifndef HAVE_W32_SYSTEM
310 # ifdef EAI_ADDRFAMILY
311 case EAI_ADDRFAMILY:err = gpg_error (GPG_ERR_EADDRNOTAVAIL); break;
313 case EAI_SYSTEM: err = gpg_error_from_syserror (); break;
315 default: err = gpg_error (GPG_ERR_UNKNOWN_ERRNO); break;
323 libdns_error_to_gpg_error (int serr)
329 case 0: ec = 0; break;
331 case DNS_ENOBUFS: ec = GPG_ERR_BUFFER_TOO_SHORT; break;
332 case DNS_EILLEGAL: ec = GPG_ERR_INV_OBJ; break;
333 case DNS_EORDER: ec = GPG_ERR_INV_ORDER; break;
334 case DNS_ESECTION: ec = GPG_ERR_DNS_SECTION; break;
335 case DNS_EUNKNOWN: ec = GPG_ERR_DNS_UNKNOWN; break;
336 case DNS_EADDRESS: ec = GPG_ERR_DNS_ADDRESS; break;
337 case DNS_ENOQUERY: ec = GPG_ERR_DNS_NO_QUERY; break;
338 case DNS_ENOANSWER:ec = GPG_ERR_DNS_NO_ANSWER; break;
339 case DNS_EFETCHED: ec = GPG_ERR_ALREADY_FETCHED; break;
340 case DNS_ESERVICE: ec = GPG_ERR_NOT_SUPPORTED; break;
341 case DNS_ENONAME: ec = GPG_ERR_NO_NAME; break;
342 case DNS_EFAIL: ec = GPG_ERR_SERVER_FAILED; break;
343 case DNS_ECONNFIN: ec = GPG_ERR_DNS_CLOSED; break;
344 case DNS_EVERIFY: ec = GPG_ERR_DNS_VERIFY; break;
348 ec = gpg_err_code_from_errno (serr);
350 ec = GPG_ERR_DNS_UNKNOWN;
353 return gpg_error (ec);
355 #endif /*USE_LIBDNS*/
359 /* Initialize libdns. Returns 0 on success; prints a diagnostic and
360 * returns an error code on failure. */
369 if (libdns.resolv_conf)
370 return 0; /* Already initialized. */
372 memset (&ld, 0, sizeof ld);
374 ld.resolv_conf = dns_resconf_open (&derr);
377 err = libdns_error_to_gpg_error (derr);
378 log_error ("failed to allocate DNS resconf object: %s\n",
385 if (!*tor_nameserver)
386 set_dns_nameserver (NULL);
388 if (!libdns_tor_port)
389 libdns_tor_port = TOR_PORT;
391 cfgstr = xtryasprintf ("[%s]:53", tor_nameserver);
393 err = gpg_error_from_syserror ();
395 err = libdns_error_to_gpg_error
396 (dns_resconf_pton (&ld.resolv_conf->nameserver[0], cfgstr));
398 log_error ("failed to set nameserver '%s': %s\n",
399 cfgstr, gpg_strerror (err));
403 ld.resolv_conf->options.tcp = DNS_RESCONF_TCP_SOCKS;
406 cfgstr = xtryasprintf ("[%s]:%d", "127.0.0.1", libdns_tor_port);
408 err = gpg_error_from_syserror ();
410 err = libdns_error_to_gpg_error
411 (dns_resconf_pton (&ld.socks_host, cfgstr));
414 log_error ("failed to set socks server '%s': %s\n",
415 cfgstr, gpg_strerror (err));
421 #ifdef HAVE_W32_SYSTEM
428 ninfo = xtrymalloc (ninfo_len);
431 err = gpg_error_from_syserror ();
435 if (GetNetworkParams (ninfo, &ninfo_len))
437 log_error ("GetNetworkParms failed: %s\n", w32_strerror (-1));
438 err = gpg_error (GPG_ERR_GENERAL);
443 for (idx=0, pip = &(ninfo->DnsServerList);
444 pip && idx < DIM (ld.resolv_conf->nameserver);
448 log_debug ("dns: dnsserver[%d] '%s'\n", idx, pip->IpAddress.String);
449 err = libdns_error_to_gpg_error
450 (dns_resconf_pton (&ld.resolv_conf->nameserver[idx],
451 pip->IpAddress.String));
453 log_error ("failed to set nameserver[%d] '%s': %s\n",
454 idx, pip->IpAddress.String, gpg_strerror (err));
463 fname = "/etc/resolv.conf";
464 err = libdns_error_to_gpg_error
465 (dns_resconf_loadpath (ld.resolv_conf, fname));
468 log_error ("failed to load '%s': %s\n", fname, gpg_strerror (err));
472 fname = "/etc/nsswitch.conf";
473 err = libdns_error_to_gpg_error
474 (dns_nssconf_loadpath (ld.resolv_conf, fname));
477 log_error ("failed to load '%s': %s\n", fname, gpg_strerror (err));
484 ld.hosts = dns_hosts_open (&derr);
487 log_error ("failed to load hosts file: %s\n", gpg_strerror (err));
488 err = libdns_error_to_gpg_error (derr);
492 /* dns_hints_local for stub mode, dns_hints_root for recursive. */
493 ld.hints = (recursive_resolver
494 ? dns_hints_root (ld.resolv_conf, &derr)
495 : dns_hints_local (ld.resolv_conf, &derr));
498 log_error ("failed to load DNS hints: %s\n", gpg_strerror (err));
499 err = libdns_error_to_gpg_error (derr);
503 /* All fine. Make the data global. */
510 #endif /*USE_LIBDNS*/
514 /* Deinitialize libdns. */
520 if (!libdns.resolv_conf)
521 return; /* Not initialized. */
524 memset (&libdns, 0, sizeof libdns);
525 dns_hints_close (ld.hints);
526 dns_hosts_close (ld.hosts);
527 dns_resconf_close (ld.resolv_conf);
529 #endif /*USE_LIBDNS*/
532 /* SIGHUP action handler for this module. With FORCE set objects are
533 * all immediately released. */
535 reload_dns_stuff (int force)
542 libdns_reinit_pending = 0;
545 libdns_reinit_pending = 1;
551 * Initialize libdns if needed and open a dns_resolver context.
552 * Returns 0 on success and stores the new context at R_RES. On
553 * failure an error code is returned and NULL stored at R_RES.
556 libdns_res_open (struct dns_resolver **r_res)
559 struct dns_resolver *res;
564 if (libdns_reinit_pending)
566 libdns_reinit_pending = 0;
570 err = libdns_init ();
577 res = dns_res_open (libdns.resolv_conf, libdns.hosts, libdns.hints, NULL,
578 dns_opts (.socks_host = &libdns.socks_host,
579 .socks_user = tor_socks_user,
580 .socks_password = tor_socks_password ),
583 return libdns_error_to_gpg_error (derr);
588 #endif /*USE_LIBDNS*/
592 /* Helper to test whether we need totry again after having swicthed
595 libdns_switch_port_p (gpg_error_t err)
597 if (tor_mode && gpg_err_code (err) == GPG_ERR_ECONNREFUSED
598 && libdns_tor_port == TOR_PORT)
600 /* Switch port and try again. */
602 log_debug ("dns: switching from SOCKS port %d to %d\n",
603 TOR_PORT, TOR_PORT2);
604 libdns_tor_port = TOR_PORT2;
605 libdns_reinit_pending = 1;
610 #endif /*USE_LIBDNS*/
614 /* Wrapper around dns_res_submit. */
616 libdns_res_submit (struct dns_resolver *res, const char *qname,
617 enum dns_type qtype, enum dns_class qclass)
619 return libdns_error_to_gpg_error (dns_res_submit (res, qname, qtype, qclass));
621 #endif /*USE_LIBDNS*/
625 /* Standard event handling loop. */
627 libdns_res_wait (struct dns_resolver *res)
631 while ((err = libdns_error_to_gpg_error (dns_res_check (res)))
632 && gpg_err_code (err) == GPG_ERR_EAGAIN)
634 if (dns_res_elapsed (res) > opt_timeout)
636 err = gpg_error (GPG_ERR_DNS_TIMEOUT);
641 dns_res_poll (res, 1);
647 #endif /*USE_LIBDNS*/
652 resolve_name_libdns (const char *name, unsigned short port,
653 int want_family, int want_socktype,
654 dns_addrinfo_t *r_dai, char **r_canonname)
657 dns_addrinfo_t daihead = NULL;
659 struct dns_resolver *res = NULL;
660 struct dns_addrinfo *ai = NULL;
661 struct addrinfo hints;
662 struct addrinfo *ent;
664 char *portstr = NULL;
671 memset (&hints, 0, sizeof hints);
672 hints.ai_family = want_family;
673 hints.ai_socktype = want_socktype;
674 hints.ai_flags = AI_ADDRCONFIG;
676 hints.ai_flags |= AI_CANONNAME;
680 snprintf (portstr_, sizeof portstr_, "%hu", port);
684 err = libdns_res_open (&res);
688 ai = dns_ai_open (name, portstr, 0, &hints, res, &derr);
691 err = libdns_error_to_gpg_error (derr);
695 /* Loop over all records. */
698 err = libdns_error_to_gpg_error (dns_ai_nextent (&ent, ai));
699 if (gpg_err_code (err) == GPG_ERR_ENOENT)
702 err = 0; /* We got some results, we're good. */
705 if (gpg_err_code (err) == GPG_ERR_EAGAIN)
707 if (dns_ai_elapsed (ai) > opt_timeout)
709 err = gpg_error (GPG_ERR_DNS_TIMEOUT);
721 if (r_canonname && ! *r_canonname && ent && ent->ai_canonname)
723 *r_canonname = xtrystrdup (ent->ai_canonname);
726 err = gpg_error_from_syserror ();
731 dai = xtrymalloc (sizeof *dai + ent->ai_addrlen -1);
734 err = gpg_error_from_syserror ();
738 dai->family = ent->ai_family;
739 dai->socktype = ent->ai_socktype;
740 dai->protocol = ent->ai_protocol;
741 dai->addrlen = ent->ai_addrlen;
742 memcpy (dai->addr, ent->ai_addr, ent->ai_addrlen);
757 xfree (*r_canonname);
760 free_dns_addrinfo (daihead);
767 #endif /*USE_LIBDNS*/
770 /* Resolve a name using the standard system function. */
772 resolve_name_standard (const char *name, unsigned short port,
773 int want_family, int want_socktype,
774 dns_addrinfo_t *r_dai, char **r_canonname)
777 dns_addrinfo_t daihead = NULL;
779 struct addrinfo *aibuf = NULL;
780 struct addrinfo hints, *ai;
788 memset (&hints, 0, sizeof hints);
789 hints.ai_family = want_family;
790 hints.ai_socktype = want_socktype;
791 hints.ai_flags = AI_ADDRCONFIG;
793 hints.ai_flags |= AI_CANONNAME;
796 snprintf (portstr, sizeof portstr, "%hu", port);
800 /* We can't use the the AI_IDN flag because that does the conversion
801 using the current locale. However, GnuPG always used UTF-8. To
802 support IDN we would need to make use of the libidn API. */
803 ret = getaddrinfo (name, *portstr? portstr : NULL, &hints, &aibuf);
807 err = map_eai_to_gpg_error (ret);
808 if (gpg_err_code (err) == GPG_ERR_NO_NAME)
810 /* There seems to be a bug in the glibc getaddrinfo function
811 if the CNAME points to a long list of A and AAAA records
812 in which case the function return NO_NAME. Let's do the
813 CNAME redirection again. */
816 if (get_dns_cname (name, &cname))
817 goto leave; /* Still no success. */
819 ret = getaddrinfo (cname, *portstr? portstr : NULL, &hints, &aibuf);
824 err = map_eai_to_gpg_error (ret);
827 err = 0; /* Yep, now it worked. */
833 if (r_canonname && aibuf && aibuf->ai_canonname)
835 *r_canonname = xtrystrdup (aibuf->ai_canonname);
838 err = gpg_error_from_syserror ();
843 for (ai = aibuf; ai; ai = ai->ai_next)
845 if (ai->ai_family != AF_INET6 && ai->ai_family != AF_INET)
848 dai = xtrymalloc (sizeof *dai + ai->ai_addrlen - 1);
849 dai->family = ai->ai_family;
850 dai->socktype = ai->ai_socktype;
851 dai->protocol = ai->ai_protocol;
852 dai->addrlen = ai->ai_addrlen;
853 memcpy (dai->addr, ai->ai_addr, ai->ai_addrlen);
860 freeaddrinfo (aibuf);
865 xfree (*r_canonname);
868 free_dns_addrinfo (daihead);
876 /* Resolve an address using the standard system function. */
878 resolve_addr_standard (const struct sockaddr *addr, int addrlen,
879 unsigned int flags, char **r_name)
889 buffer = xtrymalloc (buflen + 2 + 1);
891 return gpg_error_from_syserror ();
893 if ((flags & DNS_NUMERICHOST) || tor_mode)
896 ec = getnameinfo (addr, addrlen, buffer, buflen, NULL, 0, NI_NAMEREQD);
898 if (!ec && *buffer == '[')
899 ec = EAI_FAIL; /* A name may never start with a bracket. */
900 else if (ec == EAI_NONAME)
903 if (addr->sa_family == AF_INET6 && (flags & DNS_WITHBRACKET))
908 ec = getnameinfo (addr, addrlen, p, buflen, NULL, 0, NI_NUMERICHOST);
909 if (!ec && addr->sa_family == AF_INET6 && (flags & DNS_WITHBRACKET))
910 strcat (buffer, "]");
914 err = map_eai_to_gpg_error (ec);
917 p = xtryrealloc (buffer, strlen (buffer)+1);
919 err = gpg_error_from_syserror ();
936 /* This a wrapper around getaddrinfo with slightly different semantics.
937 NAME is the name to resolve.
938 PORT is the requested port or 0.
939 WANT_FAMILY is either 0 (AF_UNSPEC), AF_INET6, or AF_INET4.
940 WANT_SOCKETTYPE is either SOCK_STREAM or SOCK_DGRAM.
942 On success the result is stored in a linked list with the head
943 stored at the address R_AI; the caller must call gpg_addrinfo_free
944 on this. If R_CANONNAME is not NULL the official name of the host
945 is stored there as a malloced string; if that name is not available
948 resolve_dns_name (const char *name, unsigned short port,
949 int want_family, int want_socktype,
950 dns_addrinfo_t *r_ai, char **r_canonname)
955 if (!standard_resolver)
957 err = resolve_name_libdns (name, port, want_family, want_socktype,
959 if (err && libdns_switch_port_p (err))
960 err = resolve_name_libdns (name, port, want_family, want_socktype,
964 #endif /*USE_LIBDNS*/
965 err = resolve_name_standard (name, port, want_family, want_socktype,
968 log_debug ("dns: resolve_dns_name(%s): %s\n", name, gpg_strerror (err));
974 resolve_dns_addr (const struct sockaddr *addr, int addrlen,
975 unsigned int flags, char **r_name)
977 return resolve_addr_standard (addr, addrlen, flags, r_name);
981 /* Check whether NAME is an IP address. Returns true if it is either
982 an IPv6 or IPv4 numerical address. */
984 is_ip_address (const char *name)
987 int ndots, dblcol, n;
990 return 1; /* yes: A legal DNS name may not contain this character;
991 this mut be bracketed v6 address. */
993 return 0; /* No. A leading dot is not a valid IP address. */
995 /* Check whether this is a v6 address. */
996 ndots = n = dblcol = 0;
997 for (s=name; *s; s++)
1006 return 0; /* No: Only one "::" allowed. */
1015 else if (!strchr ("0123456789abcdefABCDEF", *s))
1016 return 0; /* No: Not a hex digit. */
1018 return 0; /* To many digits in a group. */
1021 return 0; /* No: Too many colons. */
1023 return 1; /* Yes: At least 2 colons indicate an v6 address. */
1026 /* Check whether it is legacy IP address. */
1028 for (s=name; *s; s++)
1033 return 0; /* No: Douple dot. */
1034 if (atoi (s+1) > 255)
1035 return 0; /* No: Ipv4 byte value too large. */
1039 else if (!strchr ("0123456789", *s))
1040 return 0; /* No: Not a digit. */
1042 return 0; /* No: More than 3 digits. */
1044 return !!(ndots == 3);
1048 /* Return true if NAME is an onion address. */
1050 is_onion_address (const char *name)
1054 len = name? strlen (name) : 0;
1055 if (len < 8 || strcmp (name + len - 6, ".onion"))
1057 /* Note that we require at least 2 characters before the suffix. */
1058 return 1; /* Yes. */
1062 /* libdns version of get_dns_cert. */
1065 get_dns_cert_libdns (const char *name, int want_certtype,
1066 void **r_key, size_t *r_keylen,
1067 unsigned char **r_fpr, size_t *r_fprlen, char **r_url)
1070 struct dns_resolver *res = NULL;
1071 struct dns_packet *ans = NULL;
1073 struct dns_rr_i rri;
1074 char host[DNS_D_MAXNAME + 1];
1078 /* Gte the query type from WANT_CERTTYPE (which in general indicates
1079 * the subtype we want). */
1080 qtype = (want_certtype < DNS_CERTTYPE_RRBASE
1082 : (want_certtype - DNS_CERTTYPE_RRBASE));
1085 err = libdns_res_open (&res);
1089 if (dns_d_anchor (host, sizeof host, name, strlen (name)) >= sizeof host)
1091 err = gpg_error (GPG_ERR_ENAMETOOLONG);
1095 err = libdns_res_submit (res, name, qtype, DNS_C_IN);
1099 err = libdns_res_wait (res);
1103 ans = dns_res_fetch (res, &derr);
1106 err = libdns_error_to_gpg_error (derr);
1110 /* Check the rcode. */
1111 switch (dns_p_rcode (ans))
1113 case DNS_RC_NOERROR: break;
1114 case DNS_RC_NXDOMAIN: err = gpg_error (GPG_ERR_NO_NAME); break;
1115 default: err = GPG_ERR_SERVER_FAILED; break;
1120 memset (&rri, 0, sizeof rri);
1121 dns_rr_i_init (&rri, ans);
1122 rri.section = DNS_S_ALL & ~DNS_S_QD;
1126 err = gpg_error (GPG_ERR_NOT_FOUND);
1127 while (dns_rr_grep (&rr, 1, &rri, ans, &derr))
1129 unsigned char *rp = ans->data + rr.rd.p;
1130 unsigned short len = rr.rd.len;
1135 /* Definitely too short - skip. */
1137 else if (want_certtype >= DNS_CERTTYPE_RRBASE
1138 && rr.type == (want_certtype - DNS_CERTTYPE_RRBASE)
1141 *r_key = xtrymalloc (len);
1143 err = gpg_error_from_syserror ();
1146 memcpy (*r_key, rp, len);
1152 else if (want_certtype >= DNS_CERTTYPE_RRBASE)
1154 /* We did not found the requested RR - skip. */
1156 else if (rr.type == T_CERT && len > 5)
1158 /* We got a CERT type. */
1159 subtype = buf16_to_u16 (rp);
1162 /* Skip the CERT key tag and algo which we don't need. */
1165 if (want_certtype && want_certtype != subtype)
1166 ; /* Not the requested subtype - skip. */
1167 else if (subtype == DNS_CERTTYPE_PGP && len && r_key && r_keylen)
1170 *r_key = xtrymalloc (len);
1172 err = gpg_error_from_syserror ();
1175 memcpy (*r_key, rp, len);
1181 else if (subtype == DNS_CERTTYPE_IPGP
1182 && len && len < 1023 && len >= rp[0] + 1)
1188 *r_fpr = xtrymalloc (*r_fprlen);
1191 err = gpg_error_from_syserror ();
1194 memcpy (*r_fpr, rp+1, *r_fprlen);
1199 if (len > *r_fprlen + 1)
1201 *r_url = xtrymalloc (len - (*r_fprlen + 1) + 1);
1204 err = gpg_error_from_syserror ();
1209 memcpy (*r_url, rp + *r_fprlen + 1, len - (*r_fprlen + 1));
1210 (*r_url)[len - (*r_fprlen + 1)] = 0;
1220 /* Unknown subtype or record too short - skip. */
1225 /* Not a requested type - skip. */
1231 dns_res_close (res);
1234 #endif /*USE_LIBDNS*/
1237 /* Standard resolver version of get_dns_cert. */
1239 get_dns_cert_standard (const char *name, int want_certtype,
1240 void **r_key, size_t *r_keylen,
1241 unsigned char **r_fpr, size_t *r_fprlen, char **r_url)
1243 #ifdef HAVE_SYSTEM_RESOLVER
1245 unsigned char *answer;
1249 /* Allocate a 64k buffer which is the limit for an DNS response. */
1250 answer = xtrymalloc (65536);
1252 return gpg_error_from_syserror ();
1254 err = gpg_error (GPG_ERR_NOT_FOUND);
1255 r = res_query (name, C_IN,
1256 (want_certtype < DNS_CERTTYPE_RRBASE
1258 : (want_certtype - DNS_CERTTYPE_RRBASE)),
1260 /* Not too big, not too small, no errors and at least 1 answer. */
1261 if (r >= sizeof (HEADER) && r <= 65536
1262 && (((HEADER *)(void *) answer)->rcode) == NOERROR
1263 && (count = ntohs (((HEADER *)(void *) answer)->ancount)))
1266 unsigned char *pt, *emsg;
1270 pt = &answer[sizeof (HEADER)];
1272 /* Skip over the query */
1274 rc = dn_skipname (pt, emsg);
1277 err = gpg_error (GPG_ERR_INV_OBJ);
1280 pt += rc + QFIXEDSZ;
1282 /* There are several possible response types for a CERT request.
1283 We're interested in the PGP (a key) and IPGP (a URI) types.
1284 Skip all others. TODO: A key is better than a URI since
1285 we've gone through all this bother to fetch it, so favor that
1286 if we have both PGP and IPGP? */
1288 while (count-- > 0 && pt < emsg)
1290 u16 type, class, dlen, ctype;
1292 rc = dn_skipname (pt, emsg); /* the name we just queried for */
1295 err = gpg_error (GPG_ERR_INV_OBJ);
1301 /* Truncated message? 15 bytes takes us to the point where
1302 we start looking at the ctype. */
1303 if ((emsg - pt) < 15)
1306 type = buf16_to_u16 (pt);
1309 class = buf16_to_u16 (pt);
1319 dlen = buf16_to_u16 (pt);
1322 /* Check the type and parse. */
1323 if (want_certtype >= DNS_CERTTYPE_RRBASE
1324 && type == (want_certtype - DNS_CERTTYPE_RRBASE)
1327 *r_key = xtrymalloc (dlen);
1329 err = gpg_error_from_syserror ();
1332 memcpy (*r_key, pt, dlen);
1338 else if (want_certtype >= DNS_CERTTYPE_RRBASE)
1340 /* We did not found the requested RR. */
1343 else if (type == T_CERT)
1345 /* We got a CERT type. */
1346 ctype = buf16_to_u16 (pt);
1349 /* Skip the CERT key tag and algo which we don't need. */
1354 /* 15 bytes takes us to here */
1355 if (want_certtype && want_certtype != ctype)
1356 ; /* Not of the requested certtype. */
1357 else if (ctype == DNS_CERTTYPE_PGP && dlen && r_key && r_keylen)
1360 *r_key = xtrymalloc (dlen);
1362 err = gpg_error_from_syserror ();
1365 memcpy (*r_key, pt, dlen);
1371 else if (ctype == DNS_CERTTYPE_IPGP
1372 && dlen && dlen < 1023 && dlen >= pt[0] + 1)
1378 *r_fpr = xtrymalloc (*r_fprlen);
1381 err = gpg_error_from_syserror ();
1384 memcpy (*r_fpr, &pt[1], *r_fprlen);
1389 if (dlen > *r_fprlen + 1)
1391 *r_url = xtrymalloc (dlen - (*r_fprlen + 1) + 1);
1394 err = gpg_error_from_syserror ();
1399 memcpy (*r_url, &pt[*r_fprlen + 1],
1400 dlen - (*r_fprlen + 1));
1401 (*r_url)[dlen - (*r_fprlen + 1)] = '\0';
1410 /* No subtype matches, so continue with the next answer. */
1415 /* Not a requested type - might be a CNAME. Try next item. */
1425 #else /*!HAVE_SYSTEM_RESOLVER*/
1428 (void)want_certtype;
1434 return gpg_error (GPG_ERR_NOT_SUPPORTED);
1436 #endif /*!HAVE_SYSTEM_RESOLVER*/
1440 /* Returns 0 on success or an error code. If a PGP CERT record was
1441 found, the malloced data is returned at (R_KEY, R_KEYLEN) and
1442 the other return parameters are set to NULL/0. If an IPGP CERT
1443 record was found the fingerprint is stored as an allocated block at
1444 R_FPR and its length at R_FPRLEN; an URL is is allocated as a
1445 string and returned at R_URL. If WANT_CERTTYPE is 0 this function
1446 returns the first CERT found with a supported type; it is expected
1447 that only one CERT record is used. If WANT_CERTTYPE is one of the
1448 supported certtypes only records with this certtype are considered
1449 and the first found is returned. (R_KEY,R_KEYLEN) are optional. */
1451 get_dns_cert (const char *name, int want_certtype,
1452 void **r_key, size_t *r_keylen,
1453 unsigned char **r_fpr, size_t *r_fprlen, char **r_url)
1466 if (!standard_resolver)
1468 err = get_dns_cert_libdns (name, want_certtype, r_key, r_keylen,
1469 r_fpr, r_fprlen, r_url);
1470 if (err && libdns_switch_port_p (err))
1471 err = get_dns_cert_libdns (name, want_certtype, r_key, r_keylen,
1472 r_fpr, r_fprlen, r_url);
1475 #endif /*USE_LIBDNS*/
1476 err = get_dns_cert_standard (name, want_certtype, r_key, r_keylen,
1477 r_fpr, r_fprlen, r_url);
1480 log_debug ("dns: get_dns_cert(%s): %s\n", name, gpg_strerror (err));
1486 priosort(const void *a,const void *b)
1488 const struct srventry *sa=a,*sb=b;
1489 if(sa->priority>sb->priority)
1491 else if(sa->priority<sb->priority)
1498 /* Libdns based helper for getsrv. Note that it is expected that NULL
1499 * is stored at the address of LIST and 0 is stored at the address of
1503 getsrv_libdns (const char *name, struct srventry **list, unsigned int *r_count)
1506 struct dns_resolver *res = NULL;
1507 struct dns_packet *ans = NULL;
1509 struct dns_rr_i rri;
1510 char host[DNS_D_MAXNAME + 1];
1512 unsigned int srvcount = 0;
1514 err = libdns_res_open (&res);
1518 if (dns_d_anchor (host, sizeof host, name, strlen (name)) >= sizeof host)
1520 err = gpg_error (GPG_ERR_ENAMETOOLONG);
1524 err = libdns_res_submit (res, name, DNS_T_SRV, DNS_C_IN);
1528 err = libdns_res_wait (res);
1532 ans = dns_res_fetch (res, &derr);
1535 err = libdns_error_to_gpg_error (derr);
1539 /* Check the rcode. */
1540 switch (dns_p_rcode (ans))
1542 case DNS_RC_NOERROR: break;
1543 case DNS_RC_NXDOMAIN: err = gpg_error (GPG_ERR_NO_NAME); break;
1544 default: err = GPG_ERR_SERVER_FAILED; break;
1549 memset (&rri, 0, sizeof rri);
1550 dns_rr_i_init (&rri, ans);
1551 rri.section = DNS_S_ALL & ~DNS_S_QD;
1553 rri.type = DNS_T_SRV;
1555 while (dns_rr_grep (&rr, 1, &rri, ans, &derr))
1557 struct dns_srv dsrv;
1558 struct srventry *srv;
1559 struct srventry *newlist;
1561 err = libdns_error_to_gpg_error (dns_srv_parse(&dsrv, &rr, ans));
1565 newlist = xtryrealloc (*list, (srvcount+1)*sizeof(struct srventry));
1568 err = gpg_error_from_syserror ();
1572 memset (&(*list)[srvcount], 0, sizeof(struct srventry));
1573 srv = &(*list)[srvcount];
1575 srv->priority = dsrv.priority;
1576 srv->weight = dsrv.weight;
1577 srv->port = dsrv.port;
1578 mem2str (srv->target, dsrv.target, sizeof srv->target);
1581 *r_count = srvcount;
1590 dns_res_close (res);
1593 #endif /*USE_LIBDNS*/
1596 /* Standard resolver based helper for getsrv. Note that it is
1597 * expected that NULL is stored at the address of LIST and 0 is stored
1598 * at the address of R_COUNT. */
1600 getsrv_standard (const char *name,
1601 struct srventry **list, unsigned int *r_count)
1603 #ifdef HAVE_SYSTEM_RESOLVER
1605 unsigned char ans[2048];
1608 unsigned char *answer = res.ans;
1609 HEADER *header = res.header;
1610 unsigned char *pt, *emsg;
1613 unsigned int srvcount = 0;
1616 /* Do not allow a query using the standard resolver in Tor mode. */
1618 return gpg_error (GPG_ERR_NOT_ENABLED);
1621 r = res_query (name, C_IN, T_SRV, answer, sizeof res.ans);
1624 return get_h_errno_as_gpg_error ();
1625 if (r < sizeof (HEADER))
1626 return gpg_error (GPG_ERR_SERVER_FAILED);
1627 if (r > sizeof res.ans)
1628 return gpg_error (GPG_ERR_SYSTEM_BUG);
1629 if (header->rcode != NOERROR || !(count=ntohs (header->ancount)))
1630 return gpg_error (GPG_ERR_NO_NAME); /* Error or no record found. */
1633 pt = &answer[sizeof(HEADER)];
1635 /* Skip over the query */
1636 rc = dn_skipname (pt, emsg);
1640 pt += rc + QFIXEDSZ;
1642 while (count-- > 0 && pt < emsg)
1644 struct srventry *srv;
1646 struct srventry *newlist;
1648 newlist = xtryrealloc (*list, (srvcount+1)*sizeof(struct srventry));
1652 memset (&(*list)[srvcount], 0, sizeof(struct srventry));
1653 srv = &(*list)[srvcount];
1656 rc = dn_skipname (pt, emsg); /* The name we just queried for. */
1661 /* Truncated message? */
1665 type = buf16_to_u16 (pt);
1667 /* We asked for SRV and got something else !? */
1671 class = buf16_to_u16 (pt);
1673 /* We asked for IN and got something else !? */
1678 dlen = buf16_to_u16 (pt);
1681 srv->priority = buf16_to_ushort (pt);
1683 srv->weight = buf16_to_ushort (pt);
1685 srv->port = buf16_to_ushort (pt);
1688 /* Get the name. 2782 doesn't allow name compression, but
1689 * dn_expand still works to pull the name out of the packet. */
1690 rc = dn_expand (answer, emsg, pt, srv->target, sizeof srv->target);
1691 if (rc == 1 && srv->target[0] == 0) /* "." */
1700 /* Corrupt packet? */
1705 *r_count = srvcount;
1711 return gpg_error (GPG_ERR_GENERAL);
1713 #else /*!HAVE_SYSTEM_RESOLVER*/
1718 return gpg_error (GPG_ERR_NOT_SUPPORTED);
1720 #endif /*!HAVE_SYSTEM_RESOLVER*/
1724 /* Note that we do not return NONAME but simply store 0 at R_COUNT. */
1726 get_dns_srv (const char *name, struct srventry **list, unsigned int *r_count)
1729 unsigned int srvcount;
1736 if (!standard_resolver)
1738 err = getsrv_libdns (name, list, &srvcount);
1739 if (err && libdns_switch_port_p (err))
1740 err = getsrv_libdns (name, list, &srvcount);
1743 #endif /*USE_LIBDNS*/
1744 err = getsrv_standard (name, list, &srvcount);
1748 if (gpg_err_code (err) == GPG_ERR_NO_NAME)
1753 /* Now we have an array of all the srv records. */
1755 /* Order by priority */
1756 qsort(*list,srvcount,sizeof(struct srventry),priosort);
1758 /* For each priority, move the zero-weighted items first. */
1759 for (i=0; i < srvcount; i++)
1763 for (j=i;j < srvcount && (*list)[i].priority == (*list)[j].priority; j++)
1765 if((*list)[j].weight==0)
1770 struct srventry temp;
1772 memcpy (&temp,&(*list)[j],sizeof(struct srventry));
1773 memcpy (&(*list)[j],&(*list)[i],sizeof(struct srventry));
1774 memcpy (&(*list)[i],&temp,sizeof(struct srventry));
1782 /* Run the RFC-2782 weighting algorithm. We don't need very high
1783 quality randomness for this, so regular libc srand/rand is
1791 srand (time (NULL)*getpid());
1795 for (i=0; i < srvcount; i++)
1798 float prio_count=0,chose;
1800 for (j=i; j < srvcount && (*list)[i].priority == (*list)[j].priority; j++)
1802 prio_count+=(*list)[j].weight;
1803 (*list)[j].run_count=prio_count;
1806 chose=prio_count*rand()/RAND_MAX;
1808 for (j=i;j<srvcount && (*list)[i].priority==(*list)[j].priority;j++)
1810 if (chose<=(*list)[j].run_count)
1815 struct srventry temp;
1817 memcpy(&temp,&(*list)[j],sizeof(struct srventry));
1818 memcpy(&(*list)[j],&(*list)[i],sizeof(struct srventry));
1819 memcpy(&(*list)[i],&temp,sizeof(struct srventry));
1830 log_debug ("dns: getsrv(%s): %s\n", name, gpg_strerror (err));
1832 log_debug ("dns: getsrv(%s) -> %u records\n", name, srvcount);
1835 *r_count = srvcount;
1842 /* libdns version of get_dns_cname. */
1844 get_dns_cname_libdns (const char *name, char **r_cname)
1847 struct dns_resolver *res;
1848 struct dns_packet *ans = NULL;
1849 struct dns_cname cname;
1852 err = libdns_res_open (&res);
1856 err = libdns_res_submit (res, name, DNS_T_CNAME, DNS_C_IN);
1860 err = libdns_res_wait (res);
1864 ans = dns_res_fetch (res, &derr);
1867 err = libdns_error_to_gpg_error (derr);
1871 /* Check the rcode. */
1872 switch (dns_p_rcode (ans))
1874 case DNS_RC_NOERROR: break;
1875 case DNS_RC_NXDOMAIN: err = gpg_error (GPG_ERR_NO_NAME); break;
1876 default: err = GPG_ERR_SERVER_FAILED; break;
1881 /* Parse the result into CNAME. */
1882 err = libdns_error_to_gpg_error (dns_p_study (ans));
1886 if (!dns_d_cname (&cname, sizeof cname, name, strlen (name), ans, &derr))
1888 err = libdns_error_to_gpg_error (derr);
1893 *r_cname = xtrystrdup (cname.host);
1895 err = gpg_error_from_syserror ();
1899 dns_res_close (res);
1902 #endif /*USE_LIBDNS*/
1905 /* Standard resolver version of get_dns_cname. */
1907 get_dns_cname_standard (const char *name, char **r_cname)
1909 #ifdef HAVE_SYSTEM_RESOLVER
1913 unsigned char ans[2048];
1916 unsigned char *answer = res.ans;
1917 HEADER *header = res.header;
1918 unsigned char *pt, *emsg;
1921 int cnamesize = 1025;
1924 /* Do not allow a query using the standard resolver in Tor mode. */
1929 r = res_query (name, C_IN, T_CERT, answer, sizeof res.ans);
1932 return get_h_errno_as_gpg_error ();
1933 if (r < sizeof (HEADER))
1934 return gpg_error (GPG_ERR_SERVER_FAILED);
1935 if (r > sizeof res.ans)
1936 return gpg_error (GPG_ERR_SYSTEM_BUG);
1937 if (header->rcode != NOERROR || !(count=ntohs (header->ancount)))
1938 return gpg_error (GPG_ERR_NO_NAME); /* Error or no record found. */
1940 return gpg_error (GPG_ERR_SERVER_FAILED);
1943 pt = &answer[sizeof(HEADER)];
1944 rc = dn_skipname (pt, emsg);
1946 return gpg_error (GPG_ERR_SERVER_FAILED);
1948 pt += rc + QFIXEDSZ;
1950 return gpg_error (GPG_ERR_SERVER_FAILED);
1952 rc = dn_skipname (pt, emsg);
1954 return gpg_error (GPG_ERR_SERVER_FAILED);
1955 pt += rc + 2 + 2 + 4;
1957 return gpg_error (GPG_ERR_SERVER_FAILED);
1958 pt += 2; /* Skip rdlen */
1960 cname = xtrymalloc (cnamesize);
1962 return gpg_error_from_syserror ();
1964 rc = dn_expand (answer, emsg, pt, cname, cnamesize -1);
1968 return gpg_error (GPG_ERR_SERVER_FAILED);
1970 *r_cname = xtryrealloc (cname, strlen (cname)+1);
1973 err = gpg_error_from_syserror ();
1979 #else /*!HAVE_SYSTEM_RESOLVER*/
1983 return gpg_error (GPG_ERR_NOT_IMPLEMENTED);
1985 #endif /*!HAVE_SYSTEM_RESOLVER*/
1990 get_dns_cname (const char *name, char **r_cname)
1997 if (!standard_resolver)
1999 err = get_dns_cname_libdns (name, r_cname);
2000 if (err && libdns_switch_port_p (err))
2001 err = get_dns_cname_libdns (name, r_cname);
2004 #endif /*USE_LIBDNS*/
2006 err = get_dns_cname_standard (name, r_cname);
2008 log_debug ("get_dns_cname(%s)%s%s\n", name,
2009 err ? ": " : " -> ",
2010 err ? gpg_strerror (err) : *r_cname);