aboutsummaryrefslogtreecommitdiffstats
path: root/lib/crypto/c_src/dh.c
blob: 38eb534d9923bd34b3f7b6b4dcbe8b8d1abcadca (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
/*
 * %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;
}