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gnupg/g10/pkglue.c
Werner Koch b7f8dec632 gpg: Use only OpenPGP public key algo ids and add the EdDSA algo id.
* common/sexputil.c (get_pk_algo_from_canon_sexp): Change to return a
string.
* g10/keygen.c (check_keygrip): Adjust for change.
* sm/certreqgen-ui.c (check_keygrip): Likewise.

* agent/pksign.c (do_encode_dsa): Remove bogus map_pk_openpgp_to_gcry.

* g10/misc.c (map_pk_openpgp_to_gcry): Remove.
(openpgp_pk_test_algo): Change to a wrapper for openpgp_pk_test_algo2.
(openpgp_pk_test_algo2): Rewrite.
(openpgp_pk_algo_usage, pubkey_nbits): Add support for EdDSA.
(openpgp_pk_algo_name): Rewrite to remove need for gcry calls.
(pubkey_get_npkey, pubkey_get_nskey): Ditto.
(pubkey_get_nsig, pubkey_get_nenc): Ditto.
* g10/keygen.c(do_create_from_keygrip):  Support EdDSA.
(common_gen, gen_ecc, ask_keysize, generate_keypair): Ditto.
* g10/build-packet.c (do_key): Ditto.
* g10/export.c (transfer_format_to_openpgp): Ditto.
* g10/getkey.c (cache_public_key): Ditto.
* g10/import.c (transfer_secret_keys): Ditto.
* g10/keylist.c (list_keyblock_print, list_keyblock_colon): Ditto.
* g10/mainproc.c (proc_pubkey_enc): Ditto.
* g10/parse-packet.c (parse_key): Ditto,
* g10/sign.c (hash_for, sign_file, make_keysig_packet): Ditto.
* g10/keyserver.c (print_keyrec): Use openpgp_pk_algo_name.
* g10/pkglue.c (pk_verify, pk_encrypt, pk_check_secret_key): Use only
OpenPGP algo ids and support EdDSA.
* g10/pubkey-enc.c (get_it): Use only OpenPGP algo ids.
* g10/seskey.c (encode_md_value): Ditto.
--

This patch separates Libgcrypt and OpenPGP public key algorithms ids
and in most cases completely removes the Libgcrypt ones.  This is
useful because for Libgcrypt we specify the algorithm in the
S-expressions and the public key ids are not anymore needed.

This patch also adds some support for PUBKEY_ALGO_EDDSA which will
eventually be used instead of merging EdDSA with ECDSA.  As of now an
experimental algorithm id is used but the plan is to write an I-D so
that we can get a new id from the IETF.  Note that EdDSA (Ed25519)
does not yet work and that more changes are required.

The ECC support is still broken right now.  Needs to be fixed.

Signed-off-by: Werner Koch <wk@gnupg.org>
2014-01-30 18:48:37 +01:00

365 lines
10 KiB
C

/* pkglue.c - public key operations glue code
* Copyright (C) 2000, 2003, 2010 Free Software Foundation, Inc.
* Copyright (C) 2014 Werner Koch
*
* This file is part of GnuPG.
*
* GnuPG is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* GnuPG 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 <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <assert.h>
#include "gpg.h"
#include "util.h"
#include "pkglue.h"
#include "main.h"
#include "options.h"
/* FIXME: Better chnage the fucntion name because mpi_ is used by
gcrypt macros. */
gcry_mpi_t
get_mpi_from_sexp (gcry_sexp_t sexp, const char *item, int mpifmt)
{
gcry_sexp_t list;
gcry_mpi_t data;
list = gcry_sexp_find_token (sexp, item, 0);
assert (list);
data = gcry_sexp_nth_mpi (list, 1, mpifmt);
assert (data);
gcry_sexp_release (list);
return data;
}
/****************
* Emulate our old PK interface here - sometime in the future we might
* change the internal design to directly fit to libgcrypt.
*/
int
pk_verify (pubkey_algo_t pkalgo, gcry_mpi_t hash,
gcry_mpi_t *data, gcry_mpi_t *pkey)
{
gcry_sexp_t s_sig, s_hash, s_pkey;
int rc;
/* Make a sexp from pkey. */
if (pkalgo == PUBKEY_ALGO_DSA)
{
rc = gcry_sexp_build (&s_pkey, NULL,
"(public-key(dsa(p%m)(q%m)(g%m)(y%m)))",
pkey[0], pkey[1], pkey[2], pkey[3]);
}
else if (pkalgo == PUBKEY_ALGO_ELGAMAL_E || pkalgo == PUBKEY_ALGO_ELGAMAL)
{
rc = gcry_sexp_build (&s_pkey, NULL,
"(public-key(elg(p%m)(g%m)(y%m)))",
pkey[0], pkey[1], pkey[2]);
}
else if (pkalgo == PUBKEY_ALGO_RSA || pkalgo == PUBKEY_ALGO_RSA_S)
{
rc = gcry_sexp_build (&s_pkey, NULL,
"(public-key(rsa(n%m)(e%m)))", pkey[0], pkey[1]);
}
else if (pkalgo == PUBKEY_ALGO_ECDSA)
{
char *curve = openpgp_oid_to_str (pkey[0]);
if (!curve)
rc = gpg_error_from_syserror ();
else
{
rc = gcry_sexp_build (&s_pkey, NULL,
"(public-key(ecdsa(curve %s)(q%m)))",
curve, pkey[1]);
xfree (curve);
}
}
else if (pkalgo == PUBKEY_ALGO_EDDSA)
{
char *curve = openpgp_oid_to_str (pkey[0]);
if (!curve)
rc = gpg_error_from_syserror ();
else
{
rc = gcry_sexp_build (&s_pkey, NULL,
"(public-key(ecc(curve %s)"
"(flags eddsa)(q%m)))",
curve, pkey[1]);
xfree (curve);
}
}
else
return GPG_ERR_PUBKEY_ALGO;
if (rc)
BUG (); /* gcry_sexp_build should never fail. */
/* Put hash into a S-Exp s_hash. */
if (pkalgo == PUBKEY_ALGO_EDDSA)
{
if (gcry_sexp_build (&s_hash, NULL,
"(data(flags eddsa)(hash-algo sha512)(value %m))",
hash))
BUG (); /* gcry_sexp_build should never fail. */
}
else
{
if (gcry_sexp_build (&s_hash, NULL, "%m", hash))
BUG (); /* gcry_sexp_build should never fail. */
}
/* Put data into a S-Exp s_sig. */
s_sig = NULL;
if (pkalgo == PUBKEY_ALGO_DSA)
{
if (!data[0] || !data[1])
rc = gpg_error (GPG_ERR_BAD_MPI);
else
rc = gcry_sexp_build (&s_sig, NULL,
"(sig-val(dsa(r%m)(s%m)))", data[0], data[1]);
}
else if (pkalgo == PUBKEY_ALGO_ECDSA)
{
if (!data[0] || !data[1])
rc = gpg_error (GPG_ERR_BAD_MPI);
else
rc = gcry_sexp_build (&s_sig, NULL,
"(sig-val(ecdsa(r%m)(s%m)))", data[0], data[1]);
}
else if (pkalgo == PUBKEY_ALGO_EDDSA)
{
if (!data[0] || !data[1])
rc = gpg_error (GPG_ERR_BAD_MPI);
else
rc = gcry_sexp_build (&s_sig, NULL,
"(sig-val(eddsa(r%M)(s%M)))", data[0], data[1]);
}
else if (pkalgo == PUBKEY_ALGO_ELGAMAL || pkalgo == PUBKEY_ALGO_ELGAMAL_E)
{
if (!data[0] || !data[1])
rc = gpg_error (GPG_ERR_BAD_MPI);
else
rc = gcry_sexp_build (&s_sig, NULL,
"(sig-val(elg(r%m)(s%m)))", data[0], data[1]);
}
else if (pkalgo == PUBKEY_ALGO_RSA || pkalgo == PUBKEY_ALGO_RSA_S)
{
if (!data[0])
rc = gpg_error (GPG_ERR_BAD_MPI);
else
rc = gcry_sexp_build (&s_sig, NULL, "(sig-val(rsa(s%m)))", data[0]);
}
else
BUG ();
if (!rc)
rc = gcry_pk_verify (s_sig, s_hash, s_pkey);
gcry_sexp_release (s_sig);
gcry_sexp_release (s_hash);
gcry_sexp_release (s_pkey);
return rc;
}
/****************
* Emulate our old PK interface here - sometime in the future we might
* change the internal design to directly fit to libgcrypt.
* PK is only required to compute the fingerprint for ECDH.
*/
int
pk_encrypt (pubkey_algo_t algo, gcry_mpi_t *resarr, gcry_mpi_t data,
PKT_public_key *pk, gcry_mpi_t *pkey)
{
gcry_sexp_t s_ciph, s_data, s_pkey;
int rc;
/* Make a sexp from pkey. */
if (algo == PUBKEY_ALGO_ELGAMAL || algo == PUBKEY_ALGO_ELGAMAL_E)
{
rc = gcry_sexp_build (&s_pkey, NULL,
"(public-key(elg(p%m)(g%m)(y%m)))",
pkey[0], pkey[1], pkey[2]);
/* Put DATA into a simplified S-expression. */
if (rc || gcry_sexp_build (&s_data, NULL, "%m", data))
BUG ();
}
else if (algo == PUBKEY_ALGO_RSA || algo == PUBKEY_ALGO_RSA_E)
{
rc = gcry_sexp_build (&s_pkey, NULL,
"(public-key(rsa(n%m)(e%m)))",
pkey[0], pkey[1]);
/* Put DATA into a simplified S-expression. */
if (rc || gcry_sexp_build (&s_data, NULL, "%m", data))
BUG ();
}
else if (algo == PUBKEY_ALGO_ECDH)
{
gcry_mpi_t k;
char *curve;
rc = pk_ecdh_generate_ephemeral_key (pkey, &k);
if (rc)
return rc;
curve = openpgp_oid_to_str (pkey[0]);
if (!curve)
rc = gpg_error_from_syserror ();
else
{
/* Now use the ephemeral secret to compute the shared point. */
rc = gcry_sexp_build (&s_pkey, NULL,
"(public-key(ecdh(curve%s)(q%m)))",
curve, pkey[1]);
xfree (curve);
/* FIXME: Take care of RC. */
/* Put K into a simplified S-expression. */
if (rc || gcry_sexp_build (&s_data, NULL, "%m", k))
BUG ();
}
}
else
return gpg_error (GPG_ERR_PUBKEY_ALGO);
/* Pass it to libgcrypt. */
rc = gcry_pk_encrypt (&s_ciph, s_data, s_pkey);
gcry_sexp_release (s_data);
gcry_sexp_release (s_pkey);
if (rc)
;
else if (algo == PUBKEY_ALGO_ECDH)
{
gcry_mpi_t shared, public, result;
byte fp[MAX_FINGERPRINT_LEN];
size_t fpn;
/* Get the shared point and the ephemeral public key. */
shared = get_mpi_from_sexp (s_ciph, "s", GCRYMPI_FMT_USG);
public = get_mpi_from_sexp (s_ciph, "e", GCRYMPI_FMT_USG);
gcry_sexp_release (s_ciph);
s_ciph = NULL;
if (DBG_CIPHER)
{
log_debug ("ECDH ephemeral key:");
gcry_mpi_dump (public);
log_printf ("\n");
}
result = NULL;
fingerprint_from_pk (pk, fp, &fpn);
if (fpn != 20)
rc = gpg_error (GPG_ERR_INV_LENGTH);
else
rc = pk_ecdh_encrypt_with_shared_point (1 /*=encrypton*/, shared,
fp, data, pkey, &result);
gcry_mpi_release (shared);
if (!rc)
{
resarr[0] = public;
resarr[1] = result;
}
else
{
gcry_mpi_release (public);
gcry_mpi_release (result);
}
}
else /* Elgamal or RSA case. */
{ /* Fixme: Add better error handling or make gnupg use
S-expressions directly. */
resarr[0] = get_mpi_from_sexp (s_ciph, "a", GCRYMPI_FMT_USG);
if (!is_RSA (algo))
resarr[1] = get_mpi_from_sexp (s_ciph, "b", GCRYMPI_FMT_USG);
}
gcry_sexp_release (s_ciph);
return rc;
}
/* Check whether SKEY is a suitable secret key. */
int
pk_check_secret_key (pubkey_algo_t pkalgo, gcry_mpi_t *skey)
{
gcry_sexp_t s_skey;
int rc;
if (pkalgo == PUBKEY_ALGO_DSA)
{
rc = gcry_sexp_build (&s_skey, NULL,
"(private-key(dsa(p%m)(q%m)(g%m)(y%m)(x%m)))",
skey[0], skey[1], skey[2], skey[3], skey[4]);
}
else if (pkalgo == PUBKEY_ALGO_ELGAMAL || pkalgo == PUBKEY_ALGO_ELGAMAL_E)
{
rc = gcry_sexp_build (&s_skey, NULL,
"(private-key(elg(p%m)(g%m)(y%m)(x%m)))",
skey[0], skey[1], skey[2], skey[3]);
}
else if (is_RSA (pkalgo))
{
rc = gcry_sexp_build (&s_skey, NULL,
"(private-key(rsa(n%m)(e%m)(d%m)(p%m)(q%m)(u%m)))",
skey[0], skey[1], skey[2], skey[3], skey[4],
skey[5]);
}
else if (pkalgo == PUBKEY_ALGO_ECDSA || pkalgo == PUBKEY_ALGO_ECDH)
{
char *curve = openpgp_oid_to_str (skey[0]);
if (!curve)
rc = gpg_error_from_syserror ();
else
{
rc = gcry_sexp_build (&s_skey, NULL,
"(private-key(ecc(curve%s)(q%m)(d%m)))",
curve, skey[1], skey[2]);
xfree (curve);
}
}
else if (pkalgo == PUBKEY_ALGO_EDDSA)
{
char *curve = openpgp_oid_to_str (skey[0]);
if (!curve)
rc = gpg_error_from_syserror ();
else
{
rc = gcry_sexp_build (&s_skey, NULL,
"(private-key(ecc(curve %s)"
"(flags eddsa)(q%m)(d%m)))",
curve, skey[1], skey[2]);
xfree (curve);
}
}
else
return GPG_ERR_PUBKEY_ALGO;
if (!rc)
{
rc = gcry_pk_testkey (s_skey);
gcry_sexp_release (s_skey);
}
return rc;
}