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/*
* %CopyrightBegin%
*
* Copyright Ericsson AB 2010-2018. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* %CopyrightEnd%
*/
#include "dh.h"
#include "bn.h"
ERL_NIF_TERM dh_generate_key_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* (PrivKey|undefined, DHParams=[P,G], Mpint, Len|0) */
DH *dh_params = NULL;
unsigned int mpint; /* 0 or 4 */
ERL_NIF_TERM head, tail;
BIGNUM *dh_p = NULL;
BIGNUM *dh_p_shared;
BIGNUM *dh_g = NULL;
BIGNUM *priv_key_in = NULL;
unsigned long len = 0;
unsigned char *pub_ptr, *prv_ptr;
int pub_len, prv_len;
ERL_NIF_TERM ret_pub, ret_prv, ret;
const BIGNUM *pub_key_gen, *priv_key_gen;
#ifdef HAS_EVP_PKEY_CTX
EVP_PKEY_CTX *ctx = NULL;
EVP_PKEY *dhkey = NULL, *params = NULL;
#endif
ASSERT(argc == 4);
if (argv[0] != atom_undefined) {
if (!get_bn_from_bin(env, argv[0], &priv_key_in))
goto bad_arg;
}
if (!enif_get_list_cell(env, argv[1], &head, &tail))
goto bad_arg;
if (!get_bn_from_bin(env, head, &dh_p))
goto bad_arg;
if (!enif_get_list_cell(env, tail, &head, &tail))
goto bad_arg;
if (!get_bn_from_bin(env, head, &dh_g))
goto bad_arg;
if (!enif_is_empty_list(env, tail))
goto bad_arg;
if (!enif_get_uint(env, argv[2], &mpint))
goto bad_arg;
if (mpint != 0 && mpint != 4)
goto bad_arg;
if (!enif_get_ulong(env, argv[3], &len))
goto bad_arg;
if (len > LONG_MAX)
goto bad_arg;
/* Load dh_params with values to use by the generator.
Mem mgmnt transfered from dh_p etc to dh_params */
if ((dh_params = DH_new()) == NULL)
goto bad_arg;
if (priv_key_in) {
if (!DH_set0_key(dh_params, NULL, priv_key_in))
goto bad_arg;
/* On success, dh_params owns priv_key_in */
priv_key_in = NULL;
}
if (!DH_set0_pqg(dh_params, dh_p, NULL, dh_g))
goto bad_arg;
dh_p_shared = dh_p; /* Don't free this because dh_params owns it */
/* On success, dh_params owns dh_p and dh_g */
dh_p = NULL;
dh_g = NULL;
if (len) {
int bn_len;
if ((bn_len = BN_num_bits(dh_p_shared)) < 0)
goto bad_arg;
dh_p_shared = NULL; /* dh_params owns the reference */
if (len >= (size_t)bn_len)
goto bad_arg;
if (!DH_set_length(dh_params, (long)len))
goto bad_arg;
}
#ifdef HAS_EVP_PKEY_CTX
if ((params = EVP_PKEY_new()) == NULL)
goto err;
/* set the key referenced by params to dh_params... */
if (EVP_PKEY_set1_DH(params, dh_params) != 1)
goto err;
if ((ctx = EVP_PKEY_CTX_new(params, NULL)) == NULL)
goto err;
if (EVP_PKEY_keygen_init(ctx) != 1)
goto err;
if ((dhkey = EVP_PKEY_new()) == NULL)
goto err;
/* key gen op, key written to ppkey (=last arg) */
if (EVP_PKEY_keygen(ctx, &dhkey) != 1)
goto err;
DH_free(dh_params);
if ((dh_params = EVP_PKEY_get1_DH(dhkey)) == NULL)
goto err;
#else
if (!DH_generate_key(dh_params))
goto err;
#endif
DH_get0_key(dh_params, &pub_key_gen, &priv_key_gen);
if ((pub_len = BN_num_bytes(pub_key_gen)) < 0)
goto err;
if ((prv_len = BN_num_bytes(priv_key_gen)) < 0)
goto err;
if ((pub_ptr = enif_make_new_binary(env, (size_t)pub_len+mpint, &ret_pub)) == NULL)
goto err;
if ((prv_ptr = enif_make_new_binary(env, (size_t)prv_len+mpint, &ret_prv)) == NULL)
goto err;
if (mpint) {
put_uint32(pub_ptr, (unsigned int)pub_len);
pub_ptr += 4;
put_uint32(prv_ptr, (unsigned int)prv_len);
prv_ptr += 4;
}
if (BN_bn2bin(pub_key_gen, pub_ptr) < 0)
goto err;
if (BN_bn2bin(priv_key_gen, prv_ptr) < 0)
goto err;
ERL_VALGRIND_MAKE_MEM_DEFINED(pub_ptr, pub_len);
ERL_VALGRIND_MAKE_MEM_DEFINED(prv_ptr, prv_len);
ret = enif_make_tuple2(env, ret_pub, ret_prv);
goto done;
bad_arg:
ret = enif_make_badarg(env);
goto done;
err:
ret = atom_error;
done:
if (priv_key_in)
BN_free(priv_key_in);
if (dh_p)
BN_free(dh_p);
if (dh_g)
BN_free(dh_g);
if (dh_params)
DH_free(dh_params);
#ifdef HAS_EVP_PKEY_CTX
if (ctx)
EVP_PKEY_CTX_free(ctx);
if (dhkey)
EVP_PKEY_free(dhkey);
if (params)
EVP_PKEY_free(params);
#endif
return ret;
}
ERL_NIF_TERM dh_compute_key_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* (OthersPublicKey, MyPrivateKey, DHParams=[P,G]) */
BIGNUM *other_pub_key = NULL;
BIGNUM *dh_p = NULL;
BIGNUM *dh_g = NULL;
BIGNUM *dummy_pub_key = NULL;
BIGNUM *priv_key = NULL;
DH *dh_priv = NULL;
ERL_NIF_TERM head, tail, ret;
ErlNifBinary ret_bin;
int size;
int ret_bin_alloc = 0;
int dh_size;
/* Check the arguments and get
my private key (dh_priv),
the peer's public key (other_pub_key),
the parameters p & q
*/
ASSERT(argc == 3);
if (!get_bn_from_bin(env, argv[0], &other_pub_key))
goto bad_arg;
if (!get_bn_from_bin(env, argv[1], &priv_key))
goto bad_arg;
if (!enif_get_list_cell(env, argv[2], &head, &tail))
goto bad_arg;
if (!get_bn_from_bin(env, head, &dh_p))
goto bad_arg;
if (!enif_get_list_cell(env, tail, &head, &tail))
goto bad_arg;
if (!get_bn_from_bin(env, head, &dh_g))
goto bad_arg;
if (!enif_is_empty_list(env, tail))
goto bad_arg;
/* Note: DH_set0_key() does not allow setting only the
* private key, although DH_compute_key() does not use the
* public key. Work around this limitation by setting
* the public key to a copy of the private key.
*/
if ((dummy_pub_key = BN_dup(priv_key)) == NULL)
goto err;
if ((dh_priv = DH_new()) == NULL)
goto err;
if (!DH_set0_key(dh_priv, dummy_pub_key, priv_key))
goto err;
/* dh_priv owns dummy_pub_key and priv_key now */
dummy_pub_key = NULL;
priv_key = NULL;
if (!DH_set0_pqg(dh_priv, dh_p, NULL, dh_g))
goto err;
/* dh_priv owns dh_p and dh_g now */
dh_p = NULL;
dh_g = NULL;
if ((dh_size = DH_size(dh_priv)) < 0)
goto err;
if (!enif_alloc_binary((size_t)dh_size, &ret_bin))
goto err;
ret_bin_alloc = 1;
if ((size = DH_compute_key(ret_bin.data, other_pub_key, dh_priv)) < 0)
goto err;
if (size == 0)
goto err;
if ((size_t)size != ret_bin.size) {
if (!enif_realloc_binary(&ret_bin, (size_t)size))
goto err;
}
ret = enif_make_binary(env, &ret_bin);
ret_bin_alloc = 0;
goto done;
bad_arg:
err:
if (ret_bin_alloc)
enif_release_binary(&ret_bin);
ret = enif_make_badarg(env);
done:
if (other_pub_key)
BN_free(other_pub_key);
if (priv_key)
BN_free(priv_key);
if (dh_p)
BN_free(dh_p);
if (dh_g)
BN_free(dh_g);
if (dummy_pub_key)
BN_free(dummy_pub_key);
if (dh_priv)
DH_free(dh_priv);
return ret;
}
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