mirror of
git://git.gnupg.org/gnupg.git
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d879c287ac
The goal is to have the ECDH code more uniform with the other algorithms. Also make error messages and variable names more similar to other places.
289 lines
7.9 KiB
C
289 lines
7.9 KiB
C
/* pkglue.c - public key operations glue code
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* Copyright (C) 2000, 2003, 2010 Free Software Foundation, Inc.
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*
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* This file is part of GnuPG.
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*
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* GnuPG is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 3 of the License, or
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* (at your option) any later version.
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*
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* GnuPG is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <http://www.gnu.org/licenses/>.
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*/
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#include <config.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <errno.h>
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#include <assert.h>
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#include "gpg.h"
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#include "util.h"
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#include "pkglue.h"
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#include "main.h"
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#include "options.h"
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/* FIXME: Better chnage the fucntion name because mpi_ is used by
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gcrypt macros. */
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gcry_mpi_t
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mpi_from_sexp (gcry_sexp_t sexp, const char * item)
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{
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gcry_sexp_t list;
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gcry_mpi_t data;
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list = gcry_sexp_find_token (sexp, item, 0);
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assert (list);
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data = gcry_sexp_nth_mpi (list, 1, 0);
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assert (data);
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gcry_sexp_release (list);
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return data;
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}
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/****************
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* Emulate our old PK interface here - sometime in the future we might
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* change the internal design to directly fit to libgcrypt.
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*/
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int
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pk_verify (int algo, gcry_mpi_t hash, gcry_mpi_t *data, gcry_mpi_t *pkey)
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{
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gcry_sexp_t s_sig, s_hash, s_pkey;
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int rc;
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const int pkalgo = map_pk_openpgp_to_gcry (algo);
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/* Make a sexp from pkey. */
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if (pkalgo == GCRY_PK_DSA)
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{
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rc = gcry_sexp_build (&s_pkey, NULL,
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"(public-key(dsa(p%m)(q%m)(g%m)(y%m)))",
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pkey[0], pkey[1], pkey[2], pkey[3]);
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}
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else if (pkalgo == GCRY_PK_ELG || pkalgo == GCRY_PK_ELG_E)
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{
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rc = gcry_sexp_build (&s_pkey, NULL,
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"(public-key(elg(p%m)(g%m)(y%m)))",
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pkey[0], pkey[1], pkey[2]);
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}
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else if (pkalgo == GCRY_PK_RSA || pkalgo == GCRY_PK_RSA_S)
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{
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rc = gcry_sexp_build (&s_pkey, NULL,
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"(public-key(rsa(n%m)(e%m)))", pkey[0], pkey[1]);
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}
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else if (pkalgo == GCRY_PK_ECDSA) /* Same as GCRY_PK_ECDH */
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{
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rc = gcry_sexp_build (&s_pkey, NULL,
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"(public-key(ecdsa(c%m)(q%m)))", pkey[0], pkey[1]);
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}
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else
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return GPG_ERR_PUBKEY_ALGO;
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if (rc)
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BUG (); /* gcry_sexp_build should never fail. */
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/* Put hash into a S-Exp s_hash. */
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if (gcry_sexp_build (&s_hash, NULL, "%m", hash))
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BUG (); /* gcry_sexp_build should never fail. */
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/* Put data into a S-Exp s_sig. */
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s_sig = NULL;
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if (pkalgo == GCRY_PK_DSA)
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{
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if (!data[0] || !data[1])
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rc = gpg_error (GPG_ERR_BAD_MPI);
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else
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rc = gcry_sexp_build (&s_sig, NULL,
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"(sig-val(dsa(r%m)(s%m)))", data[0], data[1]);
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}
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else if (pkalgo == GCRY_PK_ECDSA)
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{
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if (!data[0] || !data[1])
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rc = gpg_error (GPG_ERR_BAD_MPI);
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else
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rc = gcry_sexp_build (&s_sig, NULL,
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"(sig-val(ecdsa(r%m)(s%m)))", data[0], data[1]);
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}
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else if (pkalgo == GCRY_PK_ELG || pkalgo == GCRY_PK_ELG_E)
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{
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if (!data[0] || !data[1])
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rc = gpg_error (GPG_ERR_BAD_MPI);
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else
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rc = gcry_sexp_build (&s_sig, NULL,
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"(sig-val(elg(r%m)(s%m)))", data[0], data[1]);
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}
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else if (pkalgo == GCRY_PK_RSA || pkalgo == GCRY_PK_RSA_S)
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{
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if (!data[0])
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rc = gpg_error (GPG_ERR_BAD_MPI);
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else
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rc = gcry_sexp_build (&s_sig, NULL, "(sig-val(rsa(s%m)))", data[0]);
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}
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else
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BUG ();
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if (!rc)
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rc = gcry_pk_verify (s_sig, s_hash, s_pkey);
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gcry_sexp_release (s_sig);
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gcry_sexp_release (s_hash);
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gcry_sexp_release (s_pkey);
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return rc;
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}
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/****************
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* Emulate our old PK interface here - sometime in the future we might
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* change the internal design to directly fit to libgcrypt.
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*/
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int
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pk_encrypt (int algo, gcry_mpi_t *resarr, gcry_mpi_t data,
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const byte pk_fp[MAX_FINGERPRINT_LEN], gcry_mpi_t *pkey)
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{
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gcry_sexp_t s_ciph, s_data, s_pkey;
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int rc;
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/* Make a sexp from pkey. */
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if (algo == GCRY_PK_ELG || algo == GCRY_PK_ELG_E)
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{
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rc = gcry_sexp_build (&s_pkey, NULL,
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"(public-key(elg(p%m)(g%m)(y%m)))",
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pkey[0], pkey[1], pkey[2]);
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/* Put DATA into a simplified S-expression. */
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if (rc || gcry_sexp_build (&s_data, NULL, "%m", data))
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BUG ();
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}
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else if (algo == GCRY_PK_RSA || algo == GCRY_PK_RSA_E)
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{
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rc = gcry_sexp_build (&s_pkey, NULL,
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"(public-key(rsa(n%m)(e%m)))",
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pkey[0], pkey[1]);
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/* Put DATA into a simplified S-expression. */
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if (rc || gcry_sexp_build (&s_data, NULL, "%m", data))
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BUG ();
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}
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else if (algo == PUBKEY_ALGO_ECDH)
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{
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gcry_mpi_t k;
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rc = pk_ecdh_generate_ephemeral_key (pkey, &k);
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if (rc)
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return rc;
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/* Now use the ephemeral secret to compute the shared point. */
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rc = gcry_sexp_build (&s_pkey, NULL,
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"(public-key(ecdh(c%m)(q%m)(p%m)))",
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pkey[0], pkey[1], pkey[2]);
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/* Put K into a simplified S-expression. */
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if (rc || gcry_sexp_build (&s_data, NULL, "%m", k))
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BUG ();
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}
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else
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return gpg_error (GPG_ERR_PUBKEY_ALGO);
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/* Pass it to libgcrypt. */
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rc = gcry_pk_encrypt (&s_ciph, s_data, s_pkey);
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gcry_sexp_release (s_data);
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gcry_sexp_release (s_pkey);
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if (rc)
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;
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else if (algo == PUBKEY_ALGO_ECDH)
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{
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gcry_mpi_t shared, public, result;
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/* Get the shared point and the ephemeral public key. */
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shared = mpi_from_sexp (s_ciph, "a");
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public = mpi_from_sexp (s_ciph, "b");
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gcry_sexp_release (s_ciph);
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s_ciph = NULL;
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if (DBG_CIPHER)
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{
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log_debug ("ECDH ephemeral key:");
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gcry_mpi_dump (public);
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log_printf ("\n");
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}
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result = NULL;
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rc = pk_ecdh_encrypt_with_shared_point (1 /*=encrypton*/, shared,
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pk_fp, data, pkey, &result);
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gcry_mpi_release (shared);
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if (!rc)
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{
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resarr[0] = public;
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resarr[1] = result;
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}
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else
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{
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gcry_mpi_release (public);
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gcry_mpi_release (result);
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}
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}
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else /* Elgamal or RSA case. */
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{ /* Fixme: Add better error handling or make gnupg use
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S-expressions directly. */
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resarr[0] = mpi_from_sexp (s_ciph, "a");
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if (algo != GCRY_PK_RSA && algo != GCRY_PK_RSA_E)
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resarr[1] = mpi_from_sexp (s_ciph, "b");
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}
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gcry_sexp_release (s_ciph);
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return rc;
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}
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/* Check whether SKEY is a suitable secret key. */
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int
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pk_check_secret_key (int algo, gcry_mpi_t *skey)
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{
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gcry_sexp_t s_skey;
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int rc;
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const int gcry_pkalgo = map_pk_openpgp_to_gcry( algo );
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if (gcry_pkalgo == GCRY_PK_DSA)
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{
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rc = gcry_sexp_build (&s_skey, NULL,
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"(private-key(dsa(p%m)(q%m)(g%m)(y%m)(x%m)))",
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skey[0], skey[1], skey[2], skey[3], skey[4]);
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}
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else if (gcry_pkalgo == GCRY_PK_ELG || gcry_pkalgo == GCRY_PK_ELG_E)
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{
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rc = gcry_sexp_build (&s_skey, NULL,
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"(private-key(elg(p%m)(g%m)(y%m)(x%m)))",
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skey[0], skey[1], skey[2], skey[3]);
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}
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else if (gcry_pkalgo == GCRY_PK_RSA
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|| gcry_pkalgo == GCRY_PK_RSA_S || gcry_pkalgo == GCRY_PK_RSA_E)
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{
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rc = gcry_sexp_build (&s_skey, NULL,
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"(private-key(rsa(n%m)(e%m)(d%m)(p%m)(q%m)(u%m)))",
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skey[0], skey[1], skey[2], skey[3], skey[4],
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skey[5]);
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}
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else if (gcry_pkalgo == GCRY_PK_ECDSA || gcry_pkalgo == GCRY_PK_ECDH)
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{
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rc = gcry_sexp_build (&s_skey, NULL,
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"(private-key(ecdsa(c%m)(q%m)(d%m)))",
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skey[0], skey[1], skey[2] );
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}
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else
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return GPG_ERR_PUBKEY_ALGO;
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if (!rc)
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{
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rc = gcry_pk_testkey (s_skey);
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gcry_sexp_release (s_skey);
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}
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return rc;
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}
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