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-rw-r--r--dirmngr/dns-stuff.c2478
1 files changed, 2478 insertions, 0 deletions
diff --git a/dirmngr/dns-stuff.c b/dirmngr/dns-stuff.c
new file mode 100644
index 0000000..4a50d75
--- /dev/null
+++ b/dirmngr/dns-stuff.c
@@ -0,0 +1,2478 @@
+/* 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>
+# 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 "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 gobal 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 (void)
+{
+ gpg_error_t err;
+ struct libdns_s ld;
+ int derr;
+ char *cfgstr = 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 */
+ const char *fname;
+
+ 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));
+ 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:
+ 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 (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 ();
+ 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 (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 (&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 (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)
+ snprintf (portstr, sizeof portstr, "%hu", port);
+ else
+ *portstr = 0;
+
+ /* We can't use the AI_IDN flag because that does the conversion
+ using the current locale. However, GnuPG always used UTF-8. To
+ support IDN we would need to make use of the libidn API. */
+ ret = getaddrinfo (name, *portstr? portstr : NULL, &hints, &aibuf);
+ if (ret)
+ {
+ aibuf = NULL;
+ err = map_eai_to_gpg_error (ret);
+ if (gpg_err_code (err) == GPG_ERR_NO_NAME)
+ {
+ /* There seems to be a bug in the glibc getaddrinfo function
+ if the CNAME points to a long list of A and AAAA records
+ in which case the function return NO_NAME. Let's do the
+ CNAME redirection again. */
+ char *cname;
+
+ if (get_dns_cname (name, &cname))
+ goto leave; /* Still no success. */
+
+ ret = getaddrinfo (cname, *portstr? portstr : NULL, &hints, &aibuf);
+ xfree (cname);
+ if (ret)
+ {
+ aibuf = NULL;
+ err = map_eai_to_gpg_error (ret);
+ goto leave;
+ }
+ err = 0; /* Yep, now it worked. */
+ }
+ else
+ goto leave;
+ }
+
+ if (r_canonname && aibuf && aibuf->ai_canonname)
+ {
+ *r_canonname = xtrystrdup (aibuf->ai_canonname);
+ if (!*r_canonname)
+ {
+ err = gpg_error_from_syserror ();
+ goto leave;
+ }
+ }
+
+ for (ai = aibuf; ai; ai = ai->ai_next)
+ {
+ if (ai->ai_family != AF_INET6 && ai->ai_family != AF_INET)
+ continue;
+ if (opt_disable_ipv4 && ai->ai_family == AF_INET)
+ continue;
+ if (opt_disable_ipv6 && ai->ai_family == AF_INET6)
+ continue;
+
+ dai = xtrymalloc (sizeof *dai);
+ dai->family = ai->ai_family;
+ dai->socktype = ai->ai_socktype;
+ dai->protocol = ai->ai_protocol;
+ dai->addrlen = ai->ai_addrlen;
+ memcpy (dai->addr, ai->ai_addr, ai->ai_addrlen);
+ dai->next = daihead;
+ daihead = dai;
+ }
+
+ leave:
+ if (aibuf)
+ freeaddrinfo (aibuf);
+ if (err)
+ {
+ if (r_canonname)
+ {
+ xfree (*r_canonname);
+ *r_canonname = NULL;
+ }
+ free_dns_addrinfo (daihead);
+ }
+ else
+ *r_dai = daihead;
+ return err;
+}
+
+
+/* This a wrapper around getaddrinfo with slightly different semantics.
+ NAME is the name to resolve.
+ PORT is the requested port or 0.
+ WANT_FAMILY is either 0 (AF_UNSPEC), AF_INET6, or AF_INET4.
+ WANT_SOCKETTYPE is either SOCK_STREAM or SOCK_DGRAM.
+
+ On success the result is stored in a linked list with the head
+ stored at the address R_AI; the caller must call gpg_addrinfo_free
+ on this. If R_CANONNAME is not NULL the official name of the host
+ is stored there as a malloced string; if that name is not available
+ NULL is stored. */
+gpg_error_t
+resolve_dns_name (const char *name, unsigned short port,
+ int want_family, int want_socktype,
+ dns_addrinfo_t *r_ai, char **r_canonname)
+{
+ gpg_error_t err;
+
+#ifdef USE_LIBDNS
+ if (!standard_resolver)
+ {
+ err = resolve_name_libdns (name, port, want_family, want_socktype,
+ r_ai, r_canonname);
+ if (err && libdns_switch_port_p (err))
+ err = resolve_name_libdns (name, port, want_family, want_socktype,
+ r_ai, r_canonname);
+ }
+ else
+#endif /*USE_LIBDNS*/
+ err = resolve_name_standard (name, port, want_family, want_socktype,
+ r_ai, r_canonname);
+ if (opt_debug)
+ log_debug ("dns: resolve_dns_name(%s): %s\n", name, gpg_strerror (err));
+ return err;
+}
+
+
+#ifdef USE_LIBDNS
+/* Resolve an address using libdns. */
+static gpg_error_t
+resolve_addr_libdns (const struct sockaddr_storage *addr, int addrlen,
+ unsigned int flags, char **r_name)
+{
+ gpg_error_t err;
+ char host[DNS_D_MAXNAME + 1];
+ struct dns_resolver *res = NULL;
+ struct dns_packet *ans = NULL;
+ struct dns_ptr ptr;
+ int derr;
+
+ *r_name = NULL;
+
+ /* First we turn ADDR into a DNS name (with ".arpa" suffix). */
+ err = 0;
+ if (addr->ss_family == AF_INET6)
+ {
+ const struct sockaddr_in6 *a6 = (const struct sockaddr_in6 *)addr;
+ if (!dns_aaaa_arpa (host, sizeof host, (void*)&a6->sin6_addr))
+ err = gpg_error (GPG_ERR_INV_OBJ);
+ }
+ else if (addr->ss_family == AF_INET)
+ {
+ const struct sockaddr_in *a4 = (const struct sockaddr_in *)addr;
+ if (!dns_a_arpa (host, sizeof host, (void*)&a4->sin_addr))
+ err = gpg_error (GPG_ERR_INV_OBJ);
+ }
+ else
+ err = gpg_error (GPG_ERR_EAFNOSUPPORT);
+ if (err)
+ goto leave;
+
+
+ err = libdns_res_open (&res);
+ if (err)
+ goto leave;
+
+ err = libdns_res_submit (res, host, DNS_T_PTR, DNS_C_IN);
+ if (err)
+ goto leave;
+
+ err = libdns_res_wait (res);
+ if (err)
+ goto leave;
+
+ ans = dns_res_fetch (res, &derr);
+ if (!ans)
+ {
+ err = libdns_error_to_gpg_error (derr);
+ goto leave;
+ }
+
+ /* Check the rcode. */
+ switch (dns_p_rcode (ans))
+ {
+ case DNS_RC_NOERROR:
+ break;
+ case DNS_RC_NXDOMAIN:
+ err = gpg_error (GPG_ERR_NO_NAME);
+ break;
+ default:
+ err = GPG_ERR_SERVER_FAILED;
+ goto leave;
+ }
+
+ /* Parse the result. */
+ if (!err)
+ {
+ struct dns_rr rr;
+ struct dns_rr_i rri;
+
+ memset (&rri, 0, sizeof rri);
+ dns_rr_i_init (&rri);
+ rri.section = DNS_S_ALL & ~DNS_S_QD;
+ rri.name = host;
+ rri.type = DNS_T_PTR;
+
+ if (!dns_rr_grep (&rr, 1, &rri, ans, &derr))
+ {
+ err = gpg_error (GPG_ERR_NOT_FOUND);
+ goto leave;
+ }
+
+ err = libdns_error_to_gpg_error (dns_ptr_parse (&ptr, &rr, ans));
+ if (err)
+ goto leave;
+
+ /* Copy result. */
+ *r_name = xtrystrdup (ptr.host);
+ if (!*r_name)
+ {
+ err = gpg_error_from_syserror ();
+ goto leave;
+ }
+ /* Libdns appends the root zone part which is problematic
+ * for most other functions - strip it. */
+ if (**r_name && (*r_name)[strlen (*r_name)-1] == '.')
+ (*r_name)[strlen (*r_name)-1] = 0;
+ }
+ else /* GPG_ERR_NO_NAME */
+ {
+ char *buffer, *p;
+ int buflen;
+ int ec;
+
+ buffer = ptr.host;
+ buflen = sizeof ptr.host;
+
+ p = buffer;
+ if (addr->ss_family == AF_INET6 && (flags & DNS_WITHBRACKET))
+ {
+ *p++ = '[';
+ buflen -= 2;
+ }
+ ec = getnameinfo ((const struct sockaddr *)addr,
+ addrlen, p, buflen, NULL, 0, NI_NUMERICHOST);
+ if (ec)
+ {
+ err = map_eai_to_gpg_error (ec);
+ goto leave;
+ }
+ if (addr->ss_family == AF_INET6 && (flags & DNS_WITHBRACKET))
+ strcat (buffer, "]");
+ }
+
+ leave:
+ dns_free (ans);
+ dns_res_close (res);
+ return err;
+}
+#endif /*USE_LIBDNS*/
+
+
+/* Resolve an address using the standard system function. */
+static gpg_error_t
+resolve_addr_standard (const struct sockaddr_storage *addr, int addrlen,
+ unsigned int flags, char **r_name)
+{
+ gpg_error_t err;
+ int ec;
+ char *buffer, *p;
+ int buflen;
+
+ *r_name = NULL;
+
+ buflen = NI_MAXHOST;
+ buffer = xtrymalloc (buflen + 2 + 1);
+ if (!buffer)
+ return gpg_error_from_syserror ();
+
+ if ((flags & DNS_NUMERICHOST) || tor_mode)
+ ec = EAI_NONAME;
+ else
+ ec = getnameinfo ((const struct sockaddr *)addr,
+ addrlen, buffer, buflen, NULL, 0, NI_NAMEREQD);
+
+ if (!ec && *buffer == '[')
+ ec = EAI_FAIL; /* A name may never start with a bracket. */
+ else if (ec == EAI_NONAME)
+ {
+ p = buffer;
+ if (addr->ss_family == AF_INET6 && (flags & DNS_WITHBRACKET))
+ {
+ *p++ = '[';
+ buflen -= 2;
+ }
+ ec = getnameinfo ((const struct sockaddr *)addr,
+ addrlen, p, buflen, NULL, 0, NI_NUMERICHOST);
+ if (!ec && addr->ss_family == AF_INET6 && (flags & DNS_WITHBRACKET))
+ strcat (buffer, "]");
+ }
+
+ if (ec)
+ err = map_eai_to_gpg_error (ec);
+ else
+ {
+ p = xtryrealloc (buffer, strlen (buffer)+1);
+ if (!p)
+ err = gpg_error_from_syserror ();
+ else
+ {
+ buffer = p;
+ err = 0;
+ }
+ }
+
+ if (err)
+ xfree (buffer);
+ else
+ *r_name = buffer;
+
+ return err;
+}
+
+
+/* A wrapper around getnameinfo. */
+gpg_error_t
+resolve_dns_addr (const struct sockaddr_storage *addr, int addrlen,
+ unsigned int flags, char **r_name)
+{
+ gpg_error_t err;
+
+#ifdef USE_LIBDNS
+ /* Note that we divert to the standard resolver for NUMERICHOST. */
+ if (!standard_resolver && !(flags & DNS_NUMERICHOST))
+ {
+ err = resolve_addr_libdns (addr, addrlen, flags, r_name);
+ if (err && libdns_switch_port_p (err))
+ err = resolve_addr_libdns (addr, addrlen, flags, r_name);
+ }
+ else
+#endif /*USE_LIBDNS*/
+ err = resolve_addr_standard (addr, addrlen, flags, r_name);
+
+ if (opt_debug)
+ log_debug ("dns: resolve_dns_addr(): %s\n", gpg_strerror (err));
+ return err;
+}
+
+
+/* Check whether NAME is an IP address. Returns a true if it is
+ * either an IPv6 or a IPv4 numerical address. The actual return
+ * values can also be used to identify whether it is v4 or v6: The
+ * true value will surprisingly be 4 for IPv4 and 6 for IPv6. */
+int
+is_ip_address (const char *name)
+{
+ const char *s;
+ int ndots, dblcol, n;
+
+ if (*name == '[')
+ return 6; /* yes: A legal DNS name may not contain this character;
+ this must be bracketed v6 address. */
+ if (*name == '.')
+ return 0; /* No. A leading dot is not a valid IP address. */
+
+ /* Check whether this is a v6 address. */
+ ndots = n = dblcol = 0;
+ for (s=name; *s; s++)
+ {
+ if (*s == ':')
+ {
+ ndots++;
+ if (s[1] == ':')
+ {
+ ndots++;
+ if (dblcol)
+ return 0; /* No: Only one "::" allowed. */
+ dblcol++;
+ if (s[1])
+ s++;
+ }
+ n = 0;
+ }
+ else if (*s == '.')
+ goto legacy;
+ else if (!strchr ("0123456789abcdefABCDEF", *s))
+ return 0; /* No: Not a hex digit. */
+ else if (++n > 4)
+ return 0; /* To many digits in a group. */
+ }
+ if (ndots > 7)
+ return 0; /* No: Too many colons. */
+ else if (ndots > 1)
+ return 6; /* Yes: At least 2 colons indicate an v6 address. */
+
+ legacy:
+ /* Check whether it is legacy IP address. */
+ ndots = n = 0;
+ for (s=name; *s; s++)
+ {
+ if (*s == '.')
+ {
+ if (s[1] == '.')
+ return 0; /* No: Double dot. */
+ if (atoi (s+1) > 255)
+ return 0; /* No: Ipv4 byte value too large. */
+ ndots++;
+ n = 0;
+ }
+ else if (!strchr ("0123456789", *s))
+ return 0; /* No: Not a digit. */
+ else if (++n > 3)
+ return 0; /* No: More than 3 digits. */
+ }
+ return (ndots == 3)? 4 : 0;
+}
+
+
+/* Return true if NAME is an onion address. */
+int
+is_onion_address (const char *name)
+{
+ size_t len;
+
+ len = name? strlen (name) : 0;
+ if (len < 8 || strcmp (name + len - 6, ".onion"))
+ return 0;
+ /* Note that we require at least 2 characters before the suffix. */
+ return 1; /* Yes. */
+}
+
+
+/* libdns version of get_dns_cert. */
+#ifdef USE_LIBDNS
+static gpg_error_t
+get_dns_cert_libdns (const char *name, int want_certtype,
+ void **r_key, size_t *r_keylen,
+ unsigned char **r_fpr, size_t *r_fprlen, char **r_url)
+{
+ gpg_error_t err;
+ struct dns_resolver *res = NULL;
+ struct dns_packet *ans = NULL;
+ struct dns_rr rr;
+ struct dns_rr_i rri;
+ char host[DNS_D_MAXNAME + 1];
+ int derr;
+ int qtype;
+
+ /* Get the query type from WANT_CERTTYPE (which in general indicates
+ * the subtype we want). */
+ qtype = (want_certtype < DNS_CERTTYPE_RRBASE
+ ? T_CERT
+ : (want_certtype - DNS_CERTTYPE_RRBASE));
+
+
+ err = libdns_res_open (&res);
+ if (err)
+ goto leave;
+
+ if (dns_d_anchor (host, sizeof host, name, strlen (name)) >= sizeof host)
+ {
+ err = gpg_error (GPG_ERR_ENAMETOOLONG);
+ goto leave;
+ }
+
+ err = libdns_res_submit (res, name, qtype, DNS_C_IN);
+ if (err)
+ goto leave;
+
+ err = libdns_res_wait (res);
+ if (err)
+ goto leave;
+
+ ans = dns_res_fetch (res, &derr);
+ if (!ans)
+ {
+ err = libdns_error_to_gpg_error (derr);
+ goto leave;
+ }
+
+ /* Check the rcode. */
+ switch (dns_p_rcode (ans))
+ {
+ case DNS_RC_NOERROR: break;
+ case DNS_RC_NXDOMAIN: err = gpg_error (GPG_ERR_NO_NAME); break;
+ default: err = GPG_ERR_SERVER_FAILED; break;
+ }
+ if (err)
+ goto leave;
+
+ memset (&rri, 0, sizeof rri);
+ dns_rr_i_init (&rri);
+ rri.section = DNS_S_ALL & ~DNS_S_QD;
+ rri.name = host;
+ rri.type = qtype;
+
+ err = gpg_error (GPG_ERR_NOT_FOUND);
+ while (dns_rr_grep (&rr, 1, &rri, ans, &derr))
+ {
+ unsigned char *rp = ans->data + rr.rd.p;
+ unsigned short len = rr.rd.len;
+ u16 subtype;
+
+ if (!len)
+ {
+ /* Definitely too short - skip. */
+ }
+ else if (want_certtype >= DNS_CERTTYPE_RRBASE
+ && rr.type == (want_certtype - DNS_CERTTYPE_RRBASE)
+ && r_key)
+ {
+ *r_key = xtrymalloc (len);
+ if (!*r_key)
+ err = gpg_error_from_syserror ();
+ else
+ {
+ memcpy (*r_key, rp, len);
+ *r_keylen = len;
+ err = 0;
+ }
+ goto leave;
+ }
+ else if (want_certtype >= DNS_CERTTYPE_RRBASE)
+ {
+ /* We did not found the requested RR - skip. */
+ }
+ else if (rr.type == T_CERT && len > 5)
+ {
+ /* We got a CERT type. */
+ subtype = buf16_to_u16 (rp);
+ rp += 2; len -= 2;
+
+ /* Skip the CERT key tag and algo which we don't need. */
+ rp += 3; len -= 3;
+
+ if (want_certtype && want_certtype != subtype)
+ ; /* Not the requested subtype - skip. */
+ else if (subtype == DNS_CERTTYPE_PGP && len && r_key && r_keylen)
+ {
+ /* PGP subtype */
+ *r_key = xtrymalloc (len);
+ if (!*r_key)
+ err = gpg_error_from_syserror ();
+ else
+ {
+ memcpy (*r_key, rp, len);
+ *r_keylen = len;
+ err = 0;
+ }
+ goto leave;
+ }
+ else if (subtype == DNS_CERTTYPE_IPGP
+ && len && len < 1023 && len >= rp[0] + 1)
+ {
+ /* IPGP type */
+ *r_fprlen = rp[0];
+ if (*r_fprlen)
+ {
+ *r_fpr = xtrymalloc (*r_fprlen);
+ if (!*r_fpr)
+ {
+ err = gpg_error_from_syserror ();
+ goto leave;
+ }
+ memcpy (*r_fpr, rp+1, *r_fprlen);
+ }
+ else
+ *r_fpr = NULL;
+
+ if (len > *r_fprlen + 1)
+ {
+ *r_url = xtrymalloc (len - (*r_fprlen + 1) + 1);
+ if (!*r_url)
+ {
+ err = gpg_error_from_syserror ();
+ xfree (*r_fpr);
+ *r_fpr = NULL;
+ goto leave;
+ }
+ memcpy (*r_url, rp + *r_fprlen + 1, len - (*r_fprlen + 1));
+ (*r_url)[len - (*r_fprlen + 1)] = 0;
+ }
+ else
+ *r_url = NULL;
+
+ err = 0;
+ goto leave;
+ }
+ else
+ {
+ /* Unknown subtype or record too short - skip. */
+ }
+ }
+ else
+ {
+ /* Not a requested type - skip. */
+ }
+ }
+
+ leave:
+ dns_free (ans);
+ dns_res_close (res);
+ return err;
+}
+#endif /*USE_LIBDNS*/
+
+
+/* Standard resolver version of get_dns_cert. */
+static gpg_error_t
+get_dns_cert_standard (const char *name, int want_certtype,
+ void **r_key, size_t *r_keylen,
+ unsigned char **r_fpr, size_t *r_fprlen, char **r_url)
+{
+#ifdef HAVE_SYSTEM_RESOLVER
+ gpg_error_t err;
+ unsigned char *answer;
+ int r;
+ u16 count;
+
+ /* Allocate a 64k buffer which is the limit for an DNS response. */
+ answer = xtrymalloc (65536);
+ if (!answer)
+ return gpg_error_from_syserror ();
+
+ err = gpg_error (GPG_ERR_NOT_FOUND);
+ r = res_query (name, C_IN,
+ (want_certtype < DNS_CERTTYPE_RRBASE
+ ? T_CERT
+ : (want_certtype - DNS_CERTTYPE_RRBASE)),
+ answer, 65536);
+ /* Not too big, not too small, no errors and at least 1 answer. */
+ if (r >= sizeof (HEADER) && r <= 65536
+ && (((HEADER *)(void *) answer)->rcode) == NOERROR
+ && (count = ntohs (((HEADER *)(void *) answer)->ancount)))
+ {
+ int rc;
+ unsigned char *pt, *emsg;
+
+ emsg = &answer[r];
+
+ pt = &answer[sizeof (HEADER)];
+
+ /* Skip over the query */
+
+ rc = dn_skipname (pt, emsg);
+ if (rc == -1)
+ {
+ err = gpg_error (GPG_ERR_INV_OBJ);
+ goto leave;
+ }
+ pt += rc + QFIXEDSZ;
+
+ /* There are several possible response types for a CERT request.
+ We're interested in the PGP (a key) and IPGP (a URI) types.
+ Skip all others. TODO: A key is better than a URI since
+ we've gone through all this bother to fetch it, so favor that
+ if we have both PGP and IPGP? */
+
+ while (count-- > 0 && pt < emsg)
+ {
+ u16 type, class, dlen, ctype;
+
+ rc = dn_skipname (pt, emsg); /* the name we just queried for */
+ if (rc == -1)
+ {
+ err = gpg_error (GPG_ERR_INV_OBJ);
+ goto leave;
+ }
+
+ pt += rc;
+
+ /* Truncated message? 15 bytes takes us to the point where
+ we start looking at the ctype. */
+ if ((emsg - pt) < 15)
+ break;
+
+ type = buf16_to_u16 (pt);
+ pt += 2;
+
+ class = buf16_to_u16 (pt);
+ pt += 2;
+
+ if (class != C_IN)
+ break;
+
+ /* ttl */
+ pt += 4;
+
+ /* data length */
+ dlen = buf16_to_u16 (pt);
+ pt += 2;
+
+ /* Check the type and parse. */
+ if (want_certtype >= DNS_CERTTYPE_RRBASE
+ && type == (want_certtype - DNS_CERTTYPE_RRBASE)
+ && r_key)
+ {
+ *r_key = xtrymalloc (dlen);
+ if (!*r_key)
+ err = gpg_error_from_syserror ();
+ else
+ {
+ memcpy (*r_key, pt, dlen);
+ *r_keylen = dlen;
+ err = 0;
+ }
+ goto leave;
+ }
+ else if (want_certtype >= DNS_CERTTYPE_RRBASE)
+ {
+ /* We did not found the requested RR. */
+ pt += dlen;
+ }
+ else if (type == T_CERT)
+ {
+ /* We got a CERT type. */
+ ctype = buf16_to_u16 (pt);
+ pt += 2;
+
+ /* Skip the CERT key tag and algo which we don't need. */
+ pt += 3;
+
+ dlen -= 5;
+
+ /* 15 bytes takes us to here */
+ if (want_certtype && want_certtype != ctype)
+ ; /* Not of the requested certtype. */
+ else if (ctype == DNS_CERTTYPE_PGP && dlen && r_key && r_keylen)
+ {
+ /* PGP type */
+ *r_key = xtrymalloc (dlen);
+ if (!*r_key)
+ err = gpg_error_from_syserror ();
+ else
+ {
+ memcpy (*r_key, pt, dlen);
+ *r_keylen = dlen;
+ err = 0;
+ }
+ goto leave;
+ }
+ else if (ctype == DNS_CERTTYPE_IPGP
+ && dlen && dlen < 1023 && dlen >= pt[0] + 1)
+ {
+ /* IPGP type */
+ *r_fprlen = pt[0];
+ if (*r_fprlen)
+ {
+ *r_fpr = xtrymalloc (*r_fprlen);
+ if (!*r_fpr)
+ {
+ err = gpg_error_from_syserror ();
+ goto leave;
+ }
+ memcpy (*r_fpr, &pt[1], *r_fprlen);
+ }
+ else
+ *r_fpr = NULL;
+
+ if (dlen > *r_fprlen + 1)
+ {
+ *r_url = xtrymalloc (dlen - (*r_fprlen + 1) + 1);
+ if (!*r_url)
+ {
+ err = gpg_error_from_syserror ();
+ xfree (*r_fpr);
+ *r_fpr = NULL;
+ goto leave;
+ }
+ memcpy (*r_url, &pt[*r_fprlen + 1],
+ dlen - (*r_fprlen + 1));
+ (*r_url)[dlen - (*r_fprlen + 1)] = '\0';
+ }
+ else
+ *r_url = NULL;
+
+ err = 0;
+ goto leave;
+ }
+
+ /* No subtype matches, so continue with the next answer. */
+ pt += dlen;
+ }
+ else
+ {
+ /* Not a requested type - might be a CNAME. Try next item. */
+ pt += dlen;
+ }
+ }
+ }
+
+ leave:
+ xfree (answer);
+ return err;
+
+#else /*!HAVE_SYSTEM_RESOLVER*/
+
+ (void)name;
+ (void)want_certtype;
+ (void)r_key;
+ (void)r_keylen;
+ (void)r_fpr;
+ (void)r_fprlen;
+ (void)r_url;
+ return gpg_error (GPG_ERR_NOT_SUPPORTED);
+
+#endif /*!HAVE_SYSTEM_RESOLVER*/
+}
+
+
+/* Returns 0 on success or an error code. If a PGP CERT record was
+ found, the malloced data is returned at (R_KEY, R_KEYLEN) and
+ the other return parameters are set to NULL/0. If an IPGP CERT
+ record was found the fingerprint is stored as an allocated block at
+ R_FPR and its length at R_FPRLEN; an URL is allocated as a
+ string and returned at R_URL. If WANT_CERTTYPE is 0 this function
+ returns the first CERT found with a supported type; it is expected
+ that only one CERT record is used. If WANT_CERTTYPE is one of the
+ supported certtypes only records with this certtype are considered
+ and the first found is returned. (R_KEY,R_KEYLEN) are optional. */
+gpg_error_t
+get_dns_cert (const char *name, int want_certtype,
+ void **r_key, size_t *r_keylen,
+ unsigned char **r_fpr, size_t *r_fprlen, char **r_url)
+{
+ gpg_error_t err;
+
+ if (r_key)
+ *r_key = NULL;
+ if (r_keylen)
+ *r_keylen = 0;
+ *r_fpr = NULL;
+ *r_fprlen = 0;
+ *r_url = NULL;
+
+#ifdef USE_LIBDNS
+ if (!standard_resolver)
+ {
+ err = get_dns_cert_libdns (name, want_certtype, r_key, r_keylen,
+ r_fpr, r_fprlen, r_url);
+ if (err && libdns_switch_port_p (err))
+ err = get_dns_cert_libdns (name, want_certtype, r_key, r_keylen,
+ r_fpr, r_fprlen, r_url);
+ }
+ else
+#endif /*USE_LIBDNS*/
+ err = get_dns_cert_standard (name, want_certtype, r_key, r_keylen,
+ r_fpr, r_fprlen, r_url);
+
+ if (opt_debug)
+ log_debug ("dns: get_dns_cert(%s): %s\n", name, gpg_strerror (err));
+ return err;
+}
+
+
+static int
+priosort(const void *a,const void *b)
+{
+ const struct srventry *sa=a,*sb=b;
+ if(sa->priority>sb->priority)
+ return 1;
+ else if(sa->priority<sb->priority)
+ return -1;
+ else
+ return 0;
+}
+
+
+/* Libdns based helper for getsrv. Note that it is expected that NULL
+ * is stored at the address of LIST and 0 is stored at the address of
+ * R_COUNT. */
+#ifdef USE_LIBDNS
+static gpg_error_t
+getsrv_libdns (const char *name, struct srventry **list, unsigned int *r_count)
+{
+ gpg_error_t err;
+ struct dns_resolver *res = NULL;
+ struct dns_packet *ans = NULL;
+ struct dns_rr rr;
+ struct dns_rr_i rri;
+ char host[DNS_D_MAXNAME + 1];
+ int derr;
+ unsigned int srvcount = 0;
+
+ err = libdns_res_open (&res);
+ if (err)
+ goto leave;
+
+ if (dns_d_anchor (host, sizeof host, name, strlen (name)) >= sizeof host)
+ {
+ err = gpg_error (GPG_ERR_ENAMETOOLONG);
+ goto leave;
+ }
+
+ err = libdns_res_submit (res, name, DNS_T_SRV, DNS_C_IN);
+ if (err)
+ goto leave;
+
+ err = libdns_res_wait (res);
+ if (err)
+ goto leave;
+
+ ans = dns_res_fetch (res, &derr);
+ if (!ans)
+ {
+ err = libdns_error_to_gpg_error (derr);
+ goto leave;
+ }
+
+ /* Check the rcode. */
+ switch (dns_p_rcode (ans))
+ {
+ case DNS_RC_NOERROR: break;
+ case DNS_RC_NXDOMAIN: err = gpg_error (GPG_ERR_NO_NAME); break;
+ default: err = GPG_ERR_SERVER_FAILED; break;
+ }
+ if (err)
+ goto leave;
+
+ memset (&rri, 0, sizeof rri);
+ dns_rr_i_init (&rri);
+ rri.section = DNS_S_ALL & ~DNS_S_QD;
+ rri.name = host;
+ rri.type = DNS_T_SRV;
+
+ while (dns_rr_grep (&rr, 1, &rri, ans, &derr))
+ {
+ struct dns_srv dsrv;
+ struct srventry *srv;
+ struct srventry *newlist;
+
+ err = libdns_error_to_gpg_error (dns_srv_parse(&dsrv, &rr, ans));
+ if (err)
+ goto leave;
+
+ newlist = xtryrealloc (*list, (srvcount+1)*sizeof(struct srventry));
+ if (!newlist)
+ {
+ err = gpg_error_from_syserror ();
+ goto leave;
+ }
+ *list = newlist;
+ memset (&(*list)[srvcount], 0, sizeof(struct srventry));
+ srv = &(*list)[srvcount];
+ srvcount++;
+ srv->priority = dsrv.priority;
+ srv->weight = dsrv.weight;
+ srv->port = dsrv.port;
+ mem2str (srv->target, dsrv.target, sizeof srv->target);
+ /* Libdns appends the root zone part which is problematic for
+ * most other functions - strip it. */
+ if (*srv->target && (srv->target)[strlen (srv->target)-1] == '.')
+ (srv->target)[strlen (srv->target)-1] = 0;
+ }
+
+ *r_count = srvcount;
+
+ leave:
+ if (err)
+ {
+ xfree (*list);
+ *list = NULL;
+ }
+ dns_free (ans);
+ dns_res_close (res);
+ return err;
+}
+#endif /*USE_LIBDNS*/
+
+
+/* Standard resolver based helper for getsrv. Note that it is
+ * expected that NULL is stored at the address of LIST and 0 is stored
+ * at the address of R_COUNT. */
+static gpg_error_t
+getsrv_standard (const char *name,
+ struct srventry **list, unsigned int *r_count)
+{
+#ifdef HAVE_SYSTEM_RESOLVER
+ union {
+ unsigned char ans[2048];
+ HEADER header[1];
+ } res;
+ unsigned char *answer = res.ans;
+ HEADER *header = res.header;
+ unsigned char *pt, *emsg;
+ int r, rc;
+ u16 dlen;
+ unsigned int srvcount = 0;
+ u16 count;
+
+ /* Do not allow a query using the standard resolver in Tor mode. */
+ if (tor_mode)
+ return gpg_error (GPG_ERR_NOT_ENABLED);
+
+ my_unprotect ();
+ r = res_query (name, C_IN, T_SRV, answer, sizeof res.ans);
+ my_protect ();
+ if (r < 0)
+ return get_h_errno_as_gpg_error ();
+ if (r < sizeof (HEADER))
+ return gpg_error (GPG_ERR_SERVER_FAILED);
+ if (r > sizeof res.ans)
+ return gpg_error (GPG_ERR_SYSTEM_BUG);
+ if (header->rcode != NOERROR || !(count=ntohs (header->ancount)))
+ return gpg_error (GPG_ERR_NO_NAME); /* Error or no record found. */
+
+ emsg = &answer[r];
+ pt = &answer[sizeof(HEADER)];
+
+ /* Skip over the query */
+ rc = dn_skipname (pt, emsg);
+ if (rc == -1)
+ goto fail;
+
+ pt += rc + QFIXEDSZ;
+
+ while (count-- > 0 && pt < emsg)
+ {
+ struct srventry *srv;
+ u16 type, class;
+ struct srventry *newlist;
+
+ newlist = xtryrealloc (*list, (srvcount+1)*sizeof(struct srventry));
+ if (!newlist)
+ goto fail;
+ *list = newlist;
+ memset (&(*list)[srvcount], 0, sizeof(struct srventry));
+ srv = &(*list)[srvcount];
+ srvcount++;
+
+ rc = dn_skipname (pt, emsg); /* The name we just queried for. */
+ if (rc == -1)
+ goto fail;
+ pt += rc;
+
+ /* Truncated message? */
+ if ((emsg-pt) < 16)
+ goto fail;
+
+ type = buf16_to_u16 (pt);
+ pt += 2;
+ /* We asked for SRV and got something else !? */
+ if (type != T_SRV)
+ goto fail;
+
+ class = buf16_to_u16 (pt);
+ pt += 2;
+ /* We asked for IN and got something else !? */
+ if (class != C_IN)
+ goto fail;
+
+ pt += 4; /* ttl */
+ dlen = buf16_to_u16 (pt);
+ pt += 2;
+
+ srv->priority = buf16_to_ushort (pt);
+ pt += 2;
+ srv->weight = buf16_to_ushort (pt);
+ pt += 2;
+ srv->port = buf16_to_ushort (pt);
+ pt += 2;
+
+ /* Get the name. 2782 doesn't allow name compression, but
+ * dn_expand still works to pull the name out of the packet. */
+ rc = dn_expand (answer, emsg, pt, srv->target, sizeof srv->target);
+ if (rc == 1 && srv->target[0] == 0) /* "." */
+ {
+ xfree(*list);
+ *list = NULL;
+ return 0;
+ }
+ if (rc == -1)
+ goto fail;
+ pt += rc;
+ /* Corrupt packet? */
+ if (dlen != rc+6)
+ goto fail;
+ }
+
+ *r_count = srvcount;
+ return 0;
+
+ fail:
+ xfree (*list);
+ *list = NULL;
+ return gpg_error (GPG_ERR_GENERAL);
+
+#else /*!HAVE_SYSTEM_RESOLVER*/
+
+ (void)name;
+ (void)list;
+ (void)r_count;
+ return gpg_error (GPG_ERR_NOT_SUPPORTED);
+
+#endif /*!HAVE_SYSTEM_RESOLVER*/
+}
+
+
+/* Query a SRV record for SERVICE and PROTO for NAME. If SERVICE is
+ * NULL, NAME is expected to contain the full query name. Note that
+ * we do not return NONAME but simply store 0 at R_COUNT. On error an
+ * error code is returned and 0 stored at R_COUNT. */
+gpg_error_t
+get_dns_srv (const char *name, const char *service, const char *proto,
+ struct srventry **list, unsigned int *r_count)
+{
+ gpg_error_t err;
+ char *namebuffer = NULL;
+ unsigned int srvcount;
+ int i;
+
+ *list = NULL;
+ *r_count = 0;
+ srvcount = 0;
+
+ /* If SERVICE is given construct the query from it and PROTO. */
+ if (service)
+ {
+ namebuffer = xtryasprintf ("_%s._%s.%s",
+ service, proto? proto:"tcp", name);
+ if (!namebuffer)
+ {
+ err = gpg_error_from_syserror ();
+ goto leave;
+ }
+ name = namebuffer;
+ }
+
+
+#ifdef USE_LIBDNS
+ if (!standard_resolver)
+ {
+ err = getsrv_libdns (name, list, &srvcount);
+ if (err && libdns_switch_port_p (err))
+ err = getsrv_libdns (name, list, &srvcount);
+ }
+ else
+#endif /*USE_LIBDNS*/
+ err = getsrv_standard (name, list, &srvcount);
+
+ if (err)
+ {
+ if (gpg_err_code (err) == GPG_ERR_NO_NAME)
+ err = 0;
+ goto leave;
+ }
+
+ /* Now we have an array of all the srv records. */
+
+ /* Order by priority */
+ qsort(*list,srvcount,sizeof(struct srventry),priosort);
+
+ /* For each priority, move the zero-weighted items first. */
+ for (i=0; i < srvcount; i++)
+ {
+ int j;
+
+ for (j=i;j < srvcount && (*list)[i].priority == (*list)[j].priority; j++)
+ {
+ if((*list)[j].weight==0)
+ {
+ /* Swap j with i */
+ if(j!=i)
+ {
+ struct srventry temp;
+
+ memcpy (&temp,&(*list)[j],sizeof(struct srventry));
+ memcpy (&(*list)[j],&(*list)[i],sizeof(struct srventry));
+ memcpy (&(*list)[i],&temp,sizeof(struct srventry));
+ }
+
+ break;
+ }
+ }
+ }
+
+ /* Run the RFC-2782 weighting algorithm. We don't need very high
+ quality randomness for this, so regular libc srand/rand is
+ sufficient. */
+
+ {
+ static int done;
+ if (!done)
+ {
+ done = 1;
+ srand (time (NULL)*getpid());
+ }
+ }
+
+ for (i=0; i < srvcount; i++)
+ {
+ int j;
+ float prio_count=0,chose;
+
+ for (j=i; j < srvcount && (*list)[i].priority == (*list)[j].priority; j++)
+ {
+ prio_count+=(*list)[j].weight;
+ (*list)[j].run_count=prio_count;
+ }
+
+ chose=prio_count*rand()/RAND_MAX;
+
+ for (j=i;j<srvcount && (*list)[i].priority==(*list)[j].priority;j++)
+ {
+ if (chose<=(*list)[j].run_count)
+ {
+ /* Swap j with i */
+ if(j!=i)
+ {
+ struct srventry temp;
+
+ memcpy(&temp,&(*list)[j],sizeof(struct srventry));
+ memcpy(&(*list)[j],&(*list)[i],sizeof(struct srventry));
+ memcpy(&(*list)[i],&temp,sizeof(struct srventry));
+ }
+ break;
+ }
+ }
+ }
+
+ leave:
+ if (opt_debug)
+ {
+ if (err)
+ log_debug ("dns: getsrv(%s): %s\n", name, gpg_strerror (err));
+ else
+ log_debug ("dns: getsrv(%s) -> %u records\n", name, srvcount);
+ }
+ if (!err)
+ *r_count = srvcount;
+ xfree (namebuffer);
+ return err;
+}
+
+
+
+#ifdef USE_LIBDNS
+/* libdns version of get_dns_cname. */
+gpg_error_t
+get_dns_cname_libdns (const char *name, char **r_cname)
+{
+ gpg_error_t err;
+ struct dns_resolver *res;
+ struct dns_packet *ans = NULL;
+ struct dns_cname cname;
+ int derr;
+
+ err = libdns_res_open (&res);
+ if (err)
+ goto leave;
+
+ err = libdns_res_submit (res, name, DNS_T_CNAME, DNS_C_IN);
+ if (err)
+ goto leave;
+
+ err = libdns_res_wait (res);
+ if (err)
+ goto leave;
+
+ ans = dns_res_fetch (res, &derr);
+ if (!ans)
+ {
+ err = libdns_error_to_gpg_error (derr);
+ goto leave;
+ }
+
+ /* Check the rcode. */
+ switch (dns_p_rcode (ans))
+ {
+ case DNS_RC_NOERROR: break;
+ case DNS_RC_NXDOMAIN: err = gpg_error (GPG_ERR_NO_NAME); break;
+ default: err = GPG_ERR_SERVER_FAILED; break;
+ }
+ if (err)
+ goto leave;
+
+ /* Parse the result into CNAME. */
+ err = libdns_error_to_gpg_error (dns_p_study (ans));
+ if (err)
+ goto leave;
+
+ if (!dns_d_cname (&cname, sizeof cname, name, strlen (name), ans, &derr))
+ {
+ err = libdns_error_to_gpg_error (derr);
+ goto leave;
+ }
+
+ /* Copy result. */
+ *r_cname = xtrystrdup (cname.host);
+ if (!*r_cname)
+ err = gpg_error_from_syserror ();
+ else
+ {
+ /* Libdns appends the root zone part which is problematic
+ * for most other functions - strip it. */
+ if (**r_cname && (*r_cname)[strlen (*r_cname)-1] == '.')
+ (*r_cname)[strlen (*r_cname)-1] = 0;
+ }
+
+ leave:
+ dns_free (ans);
+ dns_res_close (res);
+ return err;
+}
+#endif /*USE_LIBDNS*/
+
+
+/* Standard resolver version of get_dns_cname. */
+gpg_error_t
+get_dns_cname_standard (const char *name, char **r_cname)
+{
+#ifdef HAVE_SYSTEM_RESOLVER
+ gpg_error_t err;
+ int rc;
+ union {
+ unsigned char ans[2048];
+ HEADER header[1];
+ } res;
+ unsigned char *answer = res.ans;
+ HEADER *header = res.header;
+ unsigned char *pt, *emsg;
+ int r;
+ char *cname;
+ int cnamesize = 1025;
+ u16 count;
+
+ /* Do not allow a query using the standard resolver in Tor mode. */
+ if (tor_mode)
+ return -1;
+
+ my_unprotect ();
+ r = res_query (name, C_IN, T_CERT, answer, sizeof res.ans);
+ my_protect ();
+ if (r < 0)
+ return get_h_errno_as_gpg_error ();
+ if (r < sizeof (HEADER))
+ return gpg_error (GPG_ERR_SERVER_FAILED);
+ if (r > sizeof res.ans)
+ return gpg_error (GPG_ERR_SYSTEM_BUG);
+ if (header->rcode != NOERROR || !(count=ntohs (header->ancount)))
+ return gpg_error (GPG_ERR_NO_NAME); /* Error or no record found. */
+ if (count != 1)
+ return gpg_error (GPG_ERR_SERVER_FAILED);
+
+ emsg = &answer[r];
+ pt = &answer[sizeof(HEADER)];
+ rc = dn_skipname (pt, emsg);
+ if (rc == -1)
+ return gpg_error (GPG_ERR_SERVER_FAILED);
+
+ pt += rc + QFIXEDSZ;
+ if (pt >= emsg)
+ return gpg_error (GPG_ERR_SERVER_FAILED);
+
+ rc = dn_skipname (pt, emsg);
+ if (rc == -1)
+ return gpg_error (GPG_ERR_SERVER_FAILED);
+ pt += rc + 2 + 2 + 4;
+ if (pt+2 >= emsg)
+ return gpg_error (GPG_ERR_SERVER_FAILED);
+ pt += 2; /* Skip rdlen */
+
+ cname = xtrymalloc (cnamesize);
+ if (!cname)
+ return gpg_error_from_syserror ();
+
+ rc = dn_expand (answer, emsg, pt, cname, cnamesize -1);
+ if (rc == -1)
+ {
+ xfree (cname);
+ return gpg_error (GPG_ERR_SERVER_FAILED);
+ }
+ *r_cname = xtryrealloc (cname, strlen (cname)+1);
+ if (!*r_cname)
+ {
+ err = gpg_error_from_syserror ();
+ xfree (cname);
+ return err;
+ }
+ return 0;
+
+#else /*!HAVE_SYSTEM_RESOLVER*/
+
+ (void)name;
+ (void)r_cname;
+ return gpg_error (GPG_ERR_NOT_IMPLEMENTED);
+
+#endif /*!HAVE_SYSTEM_RESOLVER*/
+}
+
+
+gpg_error_t
+get_dns_cname (const char *name, char **r_cname)
+{
+ gpg_error_t err;
+
+ *r_cname = NULL;
+
+#ifdef USE_LIBDNS
+ if (!standard_resolver)
+ {
+ err = get_dns_cname_libdns (name, r_cname);
+ if (err && libdns_switch_port_p (err))
+ err = get_dns_cname_libdns (name, r_cname);
+ return err;
+ }
+#endif /*USE_LIBDNS*/
+
+ err = get_dns_cname_standard (name, r_cname);
+ if (opt_debug)
+ log_debug ("get_dns_cname(%s)%s%s\n", name,
+ err ? ": " : " -> ",
+ err ? gpg_strerror (err) : *r_cname);
+ return err;
+}
+
+
+/* Check whether the machine has any usable inet devices up and
+ * running. We put this into dns because on Windows this is
+ * implemented using getaddrinfo and thus easiest done here. */
+void
+check_inet_support (int *r_v4, int *r_v6)
+{
+ if (cached_inet_support.valid)
+ {
+ *r_v4 = cached_inet_support.v4;
+ *r_v6 = cached_inet_support.v6;
+ return;
+ }
+
+ *r_v4 = *r_v6 = 0;
+
+#ifdef HAVE_W32_SYSTEM
+ {
+ gpg_error_t err;
+ int ret;
+ struct addrinfo *aibuf = NULL;
+ struct addrinfo *ai;
+
+ ret = getaddrinfo ("..localmachine", NULL, NULL, &aibuf);
+ if (ret)
+ {
+ err = map_eai_to_gpg_error (ret);
+ log_error ("%s: getaddrinfo failed: %s\n",__func__, gpg_strerror (err));
+ aibuf = NULL;
+ }
+
+ for (ai = aibuf; ai; ai = ai->ai_next)
+ {
+ if (opt_debug)
+ {
+ log_debug ("%s: family: %d\n", __func__, ai->ai_family);
+ if (ai->ai_family == AF_INET6 || ai->ai_family == AF_INET)
+ {
+ char buffer[46];
+ DWORD buflen;
+ buflen = sizeof buffer;
+ if (WSAAddressToString (ai->ai_addr, (DWORD)ai->ai_addrlen,
+ NULL, buffer, &buflen))
+ log_debug ("%s: WSAAddressToString failed: ec=%u\n",
+ __func__, (unsigned int)WSAGetLastError ());
+ else
+ log_debug ("%s: addr: %s\n", __func__, buffer);
+ }
+ }
+ if (ai->ai_family == AF_INET6)
+ {
+ struct sockaddr_in6 *v6addr = (struct sockaddr_in6 *)ai->ai_addr;
+ if (!IN6_IS_ADDR_LINKLOCAL (&v6addr->sin6_addr))
+ *r_v6 = 1;
+ }
+ else if (ai->ai_family == AF_INET)
+ {
+ *r_v4 = 1;
+ }
+ }
+
+ if (aibuf)
+ freeaddrinfo (aibuf);
+ }
+#else /*!HAVE_W32_SYSTEM*/
+ {
+ /* For now we assume that we have both protocols. */
+ *r_v4 = *r_v6 = 1;
+ }
+#endif /*!HAVE_W32_SYSTEM*/
+
+ if (opt_verbose)
+ log_info ("detected interfaces:%s%s\n",
+ *r_v4? " IPv4":"", *r_v6? " IPv6":"");
+
+ cached_inet_support.valid = 1;
+ cached_inet_support.v4 = *r_v4;
+ cached_inet_support.v6 = *r_v6;
+}