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Diffstat (limited to 'source4/heimdal/lib/hcrypto/dh.c')
| -rw-r--r-- | source4/heimdal/lib/hcrypto/dh.c | 294 |
1 files changed, 294 insertions, 0 deletions
diff --git a/source4/heimdal/lib/hcrypto/dh.c b/source4/heimdal/lib/hcrypto/dh.c new file mode 100644 index 0000000000..b558eb901c --- /dev/null +++ b/source4/heimdal/lib/hcrypto/dh.c @@ -0,0 +1,294 @@ +/* + * 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 + +RCSID("$Id: dh.c 18618 2006-10-19 17:31:51Z lha $"); + +#include <stdio.h> +#include <stdlib.h> +#include <dh.h> + +#include <roken.h> + +/* + * + */ + +DH * +DH_new(void) +{ + return DH_new_method(NULL); +} + +DH * +DH_new_method(ENGINE *engine) +{ + DH *dh; + + dh = calloc(1, sizeof(*dh)); + if (dh == NULL) + return NULL; + + dh->references = 1; + + if (engine) { + ENGINE_up_ref(engine); + dh->engine = engine; + } else { + dh->engine = ENGINE_get_default_DH(); + } + + if (dh->engine) { + dh->meth = ENGINE_get_DH(dh->engine); + if (dh->meth == NULL) { + ENGINE_finish(engine); + free(dh); + return 0; + } + } + + if (dh->meth == NULL) + dh->meth = DH_get_default_method(); + + (*dh->meth->init)(dh); + + return dh; +} + +void +DH_free(DH *dh) +{ + if (dh->references <= 0) + abort(); + + if (--dh->references > 0) + return; + + (*dh->meth->finish)(dh); + + if (dh->engine) + ENGINE_finish(dh->engine); + +#define free_if(f) if (f) { BN_free(f); } + free_if(dh->p); + free_if(dh->g); + free_if(dh->pub_key); + free_if(dh->priv_key); + free_if(dh->q); + free_if(dh->j); + free_if(dh->counter); +#undef free_if + + memset(dh, 0, sizeof(*dh)); + free(dh); +} + +int +DH_up_ref(DH *dh) +{ + return ++dh->references; +} + +int +DH_size(const DH *dh) +{ + return BN_num_bytes(dh->p); +} + +int +DH_set_ex_data(DH *dh, int idx, void *data) +{ + dh->ex_data.sk = data; + return 1; +} + +void * +DH_get_ex_data(DH *dh, int idx) +{ + return dh->ex_data.sk; +} + +int +DH_generate_parameters_ex(DH *dh, int prime_len, int generator, BN_GENCB *cb) +{ + if (dh->meth->generate_params) + return dh->meth->generate_params(dh, prime_len, generator, cb); + return 0; +} + +/* + * Check that + * + * pub_key > 1 and pub_key < p - 1 + * + * to avoid small subgroups attack. + */ + +int +DH_check_pubkey(const DH *dh, const BIGNUM *pub_key, int *codes) +{ + BIGNUM *bn = NULL, *sum = NULL; + int ret = 0; + + *codes = 0; + + bn = BN_new(); + if (bn == NULL) + goto out; + + if (!BN_set_word(bn, 1)) + goto out; + + if (BN_cmp(bn, pub_key) >= 0) + *codes |= DH_CHECK_PUBKEY_TOO_SMALL; + + sum = BN_new(); + if (sum == NULL) + goto out; + + BN_uadd(sum, pub_key, bn); + + if (BN_cmp(sum, dh->p) >= 0) + *codes |= DH_CHECK_PUBKEY_TOO_LARGE; + + ret = 1; +out: + if (bn) + BN_free(bn); + if (sum) + BN_free(sum); + + return ret; +} + +int +DH_generate_key(DH *dh) +{ + return dh->meth->generate_key(dh); +} + +int +DH_compute_key(unsigned char *shared_key, + const BIGNUM *peer_pub_key, DH *dh) +{ + int codes; + + if (!DH_check_pubkey(dh, peer_pub_key, &codes) || codes != 0) + return -1; + + return dh->meth->compute_key(shared_key, peer_pub_key, dh); +} + +int +DH_set_method(DH *dh, const DH_METHOD *method) +{ + (*dh->meth->finish)(dh); + if (dh->engine) { + ENGINE_finish(dh->engine); + dh->engine = NULL; + } + dh->meth = method; + (*dh->meth->init)(dh); + return 1; +} + +/* + * + */ + +static int +dh_null_generate_key(DH *dh) +{ + return 0; +} + +static int +dh_null_compute_key(unsigned char *shared,const BIGNUM *pub, DH *dh) +{ + return 0; +} + +static int +dh_null_init(DH *dh) +{ + return 1; +} + +static int +dh_null_finish(DH *dh) +{ + return 1; +} + +static int +dh_null_generate_params(DH *dh, int prime_num, int len, BN_GENCB *cb) +{ + return 0; +} + +static const DH_METHOD dh_null_method = { + "hcrypto null DH", + dh_null_generate_key, + dh_null_compute_key, + NULL, + dh_null_init, + dh_null_finish, + 0, + NULL, + dh_null_generate_params +}; + +extern const DH_METHOD hc_dh_imath_method; +static const DH_METHOD *dh_default_method = &hc_dh_imath_method; + +const DH_METHOD * +DH_null_method(void) +{ + return &dh_null_method; +} + +void +DH_set_default_method(const DH_METHOD *meth) +{ + dh_default_method = meth; +} + +const DH_METHOD * +DH_get_default_method(void) +{ + return dh_default_method; +} + |