security-and-privacy/gnupg
security-and-privacy/gnupg
1
0
Fork 0
mirror of git://git.gnupg.org/gnupg.git synced 2024-12-23 10:29:58 +01:00
Code Activity
gnupg/dirmngr/dns-stuff.c
Werner Koch 9695124016
dirmngr: Make sure Tor mode is also set for DNS on SIGHUP. 
* dirmngr/dns-stuff.c (enable_dns_tormode): Always succeed.
(reload_dns_stuff): Reset tor port.
* dirmngr/dirmngr.c (set_tor_mode): Also enable Tor mode for DNS.
(main): Remove warning that Tor mode may not fully work.
* dirmngr/server.c (cmd_dns_cert): Remove explicit Tor for DNS
initialization.
* dirmngr/t-dns-stuff.c (main): Remove option --new-circuit and error
checking for enable_dns_tormode.
--

This patch also resets the port on SIGHUP so that after starting Tor
SIGHUP is sufficient to use Tor.  Without the SIGHUP and when not
using the Tor browser Dirmngr would keep on trying the Tor browser
port.

Signed-off-by: Werner Koch <wk@gnupg.org>
2017-01-03 12:43:33 +01:00

2035 lines
51 KiB
C
Raw Blame History

This file contains invisible Unicode characters

This file contains invisible Unicode characters that are indistinguishable to humans but may be processed differently by a computer. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

/* 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
#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 "util.h"
#include "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
#ifndef T_CERT
# define T_CERT 37
#endif
/* 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
/* 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;
/* 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];
#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;
}
/* Set verbosity and debug mode for this module. */
void
set_dns_verbose (int verbose, int debug)
{
opt_verbose = verbose;
opt_debug = debug;
}
/* 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*/
#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 = "/etc/resolv.conf";
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)
{
log_error ("failed to load '%s': %s\n", fname, gpg_strerror (err));
goto leave;
}
#endif /* Unix */
}
ld.hosts = dns_hosts_open (&derr);
if (!ld.hosts)
{
log_error ("failed to load hosts file: %s\n", gpg_strerror (err));
err = libdns_error_to_gpg_error (derr);
goto leave;
}
/* 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)
{
log_error ("failed to load DNS hints: %s\n", gpg_strerror (err));
err = libdns_error_to_gpg_error (derr);
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
}
#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;
*r_res = NULL;
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,
dns_opts (.socks_host = &libdns.socks_host,
.socks_user = tor_socks_user,
.socks_password = tor_socks_password ),
&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;
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;
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 + ent->ai_addrlen -1);
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;
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 (port)
snprintf (portstr, sizeof portstr, "%hu", port);
else
*portstr = 0;
/* We can't use the 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;
dai = xtrymalloc (sizeof *dai + ai->ai_addrlen - 1);
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;
}
/* Resolve an address using the standard system function. */
static gpg_error_t
resolve_addr_standard (const struct sockaddr *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 (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->sa_family == AF_INET6 && (flags & DNS_WITHBRACKET))
{
*p++ = '[';
buflen -= 2;
}
ec = getnameinfo (addr, addrlen, p, buflen, NULL, 0, NI_NUMERICHOST);
if (!ec && addr->sa_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;
}
/* 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;
}
gpg_error_t
resolve_dns_addr (const struct sockaddr *addr, int addrlen,
unsigned int flags, char **r_name)
{
return resolve_addr_standard (addr, addrlen, flags, r_name);
}
/* Check whether NAME is an IP address. Returns true if it is either
an IPv6 or IPv4 numerical address. */
int
is_ip_address (const char *name)
{
const char *s;
int ndots, dblcol, n;
if (*name == '[')
return 1; /* yes: A legal DNS name may not contain this character;
this mut 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 1; /* 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: Douple 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);
}
/* 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;
/* Gte 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, ans);
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 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, ans);
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);
}
*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*/
}
/* Note that we do not return NONAME but simply store 0 at R_COUNT. */
gpg_error_t
get_dns_srv (const char *name, struct srventry **list, unsigned int *r_count)
{
gpg_error_t err;
unsigned int srvcount;
int i;
*list = NULL;
*r_count = 0;
srvcount = 0;
#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;
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;
}
View Git Blame Copy Permalink