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gnupg/dirmngr/dns-cert.c
Werner Koch 154f3ed2bf
gpg: Move all DNS access to Dirmngr.
* common/dns-cert.h: Move to ../dirmngr/.
* common/dns-cert.c: Move to ../dirmngr/.  Change args to return the
key as a buffer.
* common/t-dns-cert.c: Move to ../dirmngr/.
* common/pka.c, common/pka.h, common/t-pka.c: Remove.

* dirmngr/server.c (data_line_cookie_write): Factor code out to
data_line_write and make it a wrapper for that.
(data_line_write): New.
(cmd_dns_cert): New.
(register_commands): Register new command.

* g10/Makefile.am (LDADD): Remove DNSLIBS.
* g10/call-dirmngr.c (dns_cert_parm_s): New.
(dns_cert_data_cb, dns_cert_status_cb): New.
(gpg_dirmngr_dns_cert): New.
(gpg_dirmngr_get_pka): New.
* g10/gpgv.c (gpg_dirmngr_get_pka): New dummy function.
* g10/keyserver.c (keyserver_import_cert): Replace get_dns_cert by
gpg_dirmngr_dns_cert.
(keyserver_import_pka): Replace get_pka_info by gpg_dirmngr_get_pka.
* g10/mainproc.c: Include call-dirmngr.h.
(pka_uri_from_sig): Add CTX arg. Replace get_pka_info by
gpg_dirmngr_get_pka.
--

With this patch gpg does not do any network access itself but uses
dirmngr for that.  Note that we need to keep linking to NETLIBS due to
the logging code and because we need TCP for our socket emulation
under Windows.  Probably also required for Solaris etc.

Signed-off-by: Werner Koch <wk@gnupg.org>
2015-04-23 15:52:39 +02:00

383 lines
11 KiB
C

/* dns-cert.c - DNS CERT code (rfc-4398)
* Copyright (C) 2005, 2006, 2009 Free Software Foundation, Inc.
*
* 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 <http://www.gnu.org/licenses/>.
*/
#include <config.h>
#include <sys/types.h>
#ifdef USE_DNS_CERT
# ifdef HAVE_W32_SYSTEM
# ifdef HAVE_WINSOCK2_H
# include <winsock2.h>
# endif
# include <windows.h>
# else
# include <netinet/in.h>
# include <arpa/nameser.h>
# include <resolv.h>
# endif
# include <string.h>
#endif
#ifdef USE_ADNS
# include <adns.h>
#endif
#include "util.h"
#include "host2net.h"
#include "dns-cert.h"
/* Not every installation has gotten around to supporting CERTs
yet... */
#ifndef T_CERT
#define T_CERT 37
#endif
/* ADNS has no support for CERT yet. */
#define my_adns_r_cert 37
/* 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 wih 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)
{
#ifdef USE_DNS_CERT
#ifdef USE_ADNS
gpg_error_t err;
adns_state state;
adns_answer *answer = NULL;
unsigned int ctype;
int count;
if (r_key)
*r_key = NULL;
if (r_keylen)
*r_keylen = 0;
*r_fpr = NULL;
*r_fprlen = 0;
*r_url = NULL;
if (adns_init (&state, adns_if_noerrprint, NULL))
{
err = gpg_err_make (default_errsource, gpg_err_code_from_syserror ());
log_error ("error initializing adns: %s\n", strerror (errno));
return err;
}
if (adns_synchronous (state, name, (adns_r_unknown | my_adns_r_cert),
adns_qf_quoteok_query, &answer))
{
err = gpg_err_make (default_errsource, gpg_err_code_from_syserror ());
/* log_error ("DNS query failed: %s\n", strerror (errno)); */
adns_finish (state);
return err;
}
if (answer->status != adns_s_ok)
{
/* log_error ("DNS query returned an error: %s (%s)\n", */
/* adns_strerror (answer->status), */
/* adns_errabbrev (answer->status)); */
err = gpg_err_make (default_errsource, GPG_ERR_NOT_FOUND);
goto leave;
}
err = gpg_err_make (default_errsource, GPG_ERR_NOT_FOUND);
for (count = 0; count < answer->nrrs; count++)
{
int datalen = answer->rrs.byteblock[count].len;
const unsigned char *data = answer->rrs.byteblock[count].data;
if (datalen < 5)
continue; /* Truncated CERT record - skip. */
ctype = buf16_to_uint (data);
/* (key tag and algorithm fields are not required.) */
data += 5;
datalen -= 5;
if (want_certtype && want_certtype != ctype)
; /* Not of the requested certtype. */
else if (ctype == DNS_CERTTYPE_PGP && datalen >= 11 && r_key && r_keylen)
{
/* CERT type is PGP. Gpg checks for a minimum length of 11,
thus we do the same. */
*r_key = xtrymalloc (datalen);
if (!*r_key)
err = gpg_err_make (default_errsource,
gpg_err_code_from_syserror ());
else
{
memcpy (*r_key, data, datalen);
*r_keylen = datalen;
err = 0;
}
goto leave;
}
else if (ctype == DNS_CERTTYPE_IPGP && datalen && datalen < 1023
&& datalen >= data[0] + 1 && r_fpr && r_fprlen && r_url)
{
/* CERT type is IPGP. We made sure that the data is
plausible and that the caller requested this
information. */
*r_fprlen = data[0];
if (*r_fprlen)
{
*r_fpr = xtrymalloc (*r_fprlen);
if (!*r_fpr)
{
err = gpg_err_make (default_errsource,
gpg_err_code_from_syserror ());
goto leave;
}
memcpy (*r_fpr, data + 1, *r_fprlen);
}
else
*r_fpr = NULL;
if (datalen > *r_fprlen + 1)
{
*r_url = xtrymalloc (datalen - (*r_fprlen + 1) + 1);
if (!*r_url)
{
err = gpg_err_make (default_errsource,
gpg_err_code_from_syserror ());
xfree (*r_fpr);
*r_fpr = NULL;
goto leave;
}
memcpy (*r_url,
data + (*r_fprlen + 1), datalen - (*r_fprlen + 1));
(*r_url)[datalen - (*r_fprlen + 1)] = '\0';
}
else
*r_url = NULL;
err = 0;
goto leave;
}
}
leave:
adns_free (answer);
adns_finish (state);
return err;
#else /*!USE_ADNS*/
gpg_error_t err;
unsigned char *answer;
int r;
u16 count;
if (r_key)
*r_key = NULL;
if (r_keylen)
*r_keylen = 0;
*r_fpr = NULL;
*r_fprlen = 0;
*r_url = NULL;
/* Allocate a 64k buffer which is the limit for an DNS response. */
answer = xtrymalloc (65536);
if (!answer)
return gpg_err_make (default_errsource, gpg_err_code_from_syserror ());
err = gpg_err_make (default_errsource, GPG_ERR_NOT_FOUND);
r = res_query (name, C_IN, T_CERT, answer, 65536);
/* Not too big, not too small, no errors and at least 1 answer. */
if (r >= sizeof (HEADER) && r <= 65536
&& (((HEADER *) answer)->rcode) == NOERROR
&& (count = ntohs (((HEADER *) 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_err_make (default_errsource, 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_err_make (default_errsource, 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;
/* We asked for CERT and got something else - might be a
CNAME, so loop around again. */
if (type != T_CERT)
{
pt += dlen;
continue;
}
/* The 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_err_make (default_errsource,
gpg_err_code_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_err_make (default_errsource,
gpg_err_code_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_fpr)
{
err = gpg_err_make (default_errsource,
gpg_err_code_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;
}
/* Neither type matches, so go around to the next answer. */
pt += dlen;
}
}
leave:
xfree (answer);
return err;
#endif /*!USE_ADNS */
#else /* !USE_DNS_CERT */
(void)name;
if (r_key)
*r_key = NULL;
if (r_keylen)
*r_keylen = NULL;
*r_fpr = NULL;
*r_fprlen = 0;
*r_url = NULL;
return gpg_err_make (default_errsource, GPG_ERR_NOT_SUPPORTED);
#endif
}