diff options
Diffstat (limited to 'source4/heimdal/lib/des/dh-imath.c')
| -rw-r--r-- | source4/heimdal/lib/des/dh-imath.c | 243 |
1 files changed, 243 insertions, 0 deletions
diff --git a/source4/heimdal/lib/des/dh-imath.c b/source4/heimdal/lib/des/dh-imath.c new file mode 100644 index 0000000000..ebf02c72be --- /dev/null +++ b/source4/heimdal/lib/des/dh-imath.c @@ -0,0 +1,243 @@ +/* + * Copyright (c) 2006 Kungliga Tekniska Högskolan + * (Royal Institute of Technology, Stockholm, Sweden). + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * 3. Neither the name of the Institute nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#ifdef HAVE_CONFIG_H +#include <config.h> +#endif + +#include <stdio.h> +#include <stdlib.h> +#include <dh.h> + +#include <roken.h> + +#include "imath/imath.h" + +RCSID("$Id: dh-imath.c,v 1.6 2006/10/20 06:56:57 lha Exp $"); + +static void +BN2mpz(mpz_t *s, const BIGNUM *bn) +{ + size_t len; + void *p; + + len = BN_num_bytes(bn); + p = malloc(len); + BN_bn2bin(bn, p); + mp_int_read_unsigned(s, p, len); + free(p); +} + + +static BIGNUM * +mpz2BN(mpz_t *s) +{ + size_t size; + BIGNUM *bn; + void *p; + + size = mp_int_unsigned_len(s); + p = malloc(size); + if (p == NULL && size != 0) + return NULL; + mp_int_to_unsigned(s, p, size); + + bn = BN_bin2bn(p, size, NULL); + free(p); + return bn; +} + +/* + * + */ + +#define DH_NUM_TRIES 10 + +static int +dh_generate_key(DH *dh) +{ + mpz_t pub, priv_key, g, p; + int have_private_key = (dh->priv_key != NULL); + int codes, times = 0; + mp_result res; + + if (dh->p == NULL || dh->g == NULL) + return 0; + + while (times++ < DH_NUM_TRIES) { + if (!have_private_key) { + size_t bits = BN_num_bits(dh->p); + + if (dh->priv_key) + BN_free(dh->priv_key); + + dh->priv_key = BN_new(); + if (dh->priv_key == NULL) + return 0; + if (!BN_rand(dh->priv_key, bits - 1, 0, 0)) { + BN_clear_free(dh->priv_key); + dh->priv_key = NULL; + return 0; + } + } + if (dh->pub_key) + BN_free(dh->pub_key); + + mp_int_init(&pub); + mp_int_init(&priv_key); + mp_int_init(&g); + mp_int_init(&p); + + BN2mpz(&priv_key, dh->priv_key); + BN2mpz(&g, dh->g); + BN2mpz(&p, dh->p); + + res = mp_int_exptmod(&g, &priv_key, &p, &pub); + + mp_int_clear(&priv_key); + mp_int_clear(&g); + mp_int_clear(&p); + if (res != MP_OK) + continue; + + dh->pub_key = mpz2BN(&pub); + mp_int_clear(&pub); + if (dh->pub_key == NULL) + return 0; + + if (DH_check_pubkey(dh, dh->pub_key, &codes) && codes == 0) + break; + if (have_private_key) + return 0; + } + + if (times >= DH_NUM_TRIES) { + if (!have_private_key && dh->priv_key) { + BN_free(dh->priv_key); + dh->priv_key = NULL; + } + if (dh->pub_key) { + BN_free(dh->pub_key); + dh->pub_key = NULL; + } + return 0; + } + + return 1; +} + +static int +dh_compute_key(unsigned char *shared, const BIGNUM * pub, DH *dh) +{ + mpz_t s, priv_key, p, peer_pub; + size_t size = 0; + mp_result res; + + if (dh->pub_key == NULL || dh->g == NULL || dh->priv_key == NULL) + return -1; + + mp_int_init(&p); + BN2mpz(&p, dh->p); + + mp_int_init(&peer_pub); + BN2mpz(&peer_pub, pub); + + /* check if peers pubkey is reasonable */ + if (MP_SIGN(&peer_pub) == MP_NEG + || mp_int_compare(&peer_pub, &p) >= 0 + || mp_int_compare_value(&peer_pub, 1) <= 0) + { + mp_int_clear(&p); + mp_int_clear(&peer_pub); + return -1; + } + + mp_int_init(&priv_key); + BN2mpz(&priv_key, dh->priv_key); + + mp_int_init(&s); + + mp_int_exptmod(&peer_pub, &priv_key, &p, &s); + + mp_int_clear(&p); + mp_int_clear(&peer_pub); + mp_int_clear(&priv_key); + + size = mp_int_unsigned_len(&s); + res = mp_int_to_unsigned(&s, shared, size); + mp_int_clear(&s); + + return (res == MP_OK) ? size : -1; +} + +static int +dh_generate_params(DH *dh, int a, int b, BN_GENCB *callback) +{ + /* groups should already be known, we don't care about this */ + return 0; +} + +static int +dh_init(DH *dh) +{ + return 1; +} + +static int +dh_finish(DH *dh) +{ + return 1; +} + + +/* + * + */ + +const DH_METHOD hc_dh_imath_method = { + "hcrypto imath DH", + dh_generate_key, + dh_compute_key, + NULL, + dh_init, + dh_finish, + 0, + NULL, + dh_generate_params +}; + +const DH_METHOD * +DH_imath_method(void) +{ + return &hc_dh_imath_method; +} |