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
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
|
/*
* Copyright 1995-2019 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the Apache License 2.0 (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
/*
* DH low level APIs are deprecated for public use, but still ok for
* internal use.
*/
#include "internal/deprecated.h"
#include <stdio.h>
#include "internal/cryptlib.h"
#include <openssl/bn.h>
#include "dh_local.h"
#include "crypto/dh.h"
/*-
* Check that p and g are suitable enough
*
* p is odd
* 1 < g < p - 1
*/
int DH_check_params_ex(const DH *dh)
{
int errflags = 0;
if (!DH_check_params(dh, &errflags))
return 0;
if ((errflags & DH_CHECK_P_NOT_PRIME) != 0)
DHerr(DH_F_DH_CHECK_PARAMS_EX, DH_R_CHECK_P_NOT_PRIME);
if ((errflags & DH_NOT_SUITABLE_GENERATOR) != 0)
DHerr(DH_F_DH_CHECK_PARAMS_EX, DH_R_NOT_SUITABLE_GENERATOR);
if ((errflags & DH_MODULUS_TOO_SMALL) != 0)
DHerr(DH_F_DH_CHECK_PARAMS_EX, DH_R_MODULUS_TOO_SMALL);
if ((errflags & DH_MODULUS_TOO_LARGE) != 0)
DHerr(DH_F_DH_CHECK_PARAMS_EX, DH_R_MODULUS_TOO_LARGE);
return errflags == 0;
}
#ifdef FIPS_MODE
int DH_check_params(const DH *dh, int *ret)
{
int nid;
*ret = 0;
/*
* SP800-56A R3 Section 5.5.2 Assurances of Domain Parameter Validity
* (1a) The domain parameters correspond to any approved safe prime group.
*/
nid = DH_get_nid((DH *)dh);
if (nid != NID_undef)
return 1;
/*
* OR
* (2b) FFC domain params conform to FIPS-186-4 explicit domain param
* validity tests.
*/
return ffc_params_FIPS186_4_validate(&dh->params, FFC_PARAM_TYPE_DH, NULL,
FFC_PARAMS_VALIDATE_ALL, ret, NULL);
}
#else
int DH_check_params(const DH *dh, int *ret)
{
int ok = 0;
BIGNUM *tmp = NULL;
BN_CTX *ctx = NULL;
*ret = 0;
ctx = BN_CTX_new();
if (ctx == NULL)
goto err;
BN_CTX_start(ctx);
tmp = BN_CTX_get(ctx);
if (tmp == NULL)
goto err;
if (!BN_is_odd(dh->params.p))
*ret |= DH_CHECK_P_NOT_PRIME;
if (BN_is_negative(dh->params.g)
|| BN_is_zero(dh->params.g)
|| BN_is_one(dh->params.g))
*ret |= DH_NOT_SUITABLE_GENERATOR;
if (BN_copy(tmp, dh->params.p) == NULL || !BN_sub_word(tmp, 1))
goto err;
if (BN_cmp(dh->params.g, tmp) >= 0)
*ret |= DH_NOT_SUITABLE_GENERATOR;
if (BN_num_bits(dh->params.p) < DH_MIN_MODULUS_BITS)
*ret |= DH_MODULUS_TOO_SMALL;
if (BN_num_bits(dh->params.p) > OPENSSL_DH_MAX_MODULUS_BITS)
*ret |= DH_MODULUS_TOO_LARGE;
ok = 1;
err:
BN_CTX_end(ctx);
BN_CTX_free(ctx);
return ok;
}
#endif /* FIPS_MODE */
/*-
* Check that p is a safe prime and
* g is a suitable generator.
*/
int DH_check_ex(const DH *dh)
{
int errflags = 0;
if (!DH_check(dh, &errflags))
return 0;
if ((errflags & DH_NOT_SUITABLE_GENERATOR) != 0)
DHerr(DH_F_DH_CHECK_EX, DH_R_NOT_SUITABLE_GENERATOR);
if ((errflags & DH_CHECK_Q_NOT_PRIME) != 0)
DHerr(DH_F_DH_CHECK_EX, DH_R_CHECK_Q_NOT_PRIME);
if ((errflags & DH_CHECK_INVALID_Q_VALUE) != 0)
DHerr(DH_F_DH_CHECK_EX, DH_R_CHECK_INVALID_Q_VALUE);
if ((errflags & DH_CHECK_INVALID_J_VALUE) != 0)
DHerr(DH_F_DH_CHECK_EX, DH_R_CHECK_INVALID_J_VALUE);
if ((errflags & DH_UNABLE_TO_CHECK_GENERATOR) != 0)
DHerr(DH_F_DH_CHECK_EX, DH_R_UNABLE_TO_CHECK_GENERATOR);
if ((errflags & DH_CHECK_P_NOT_PRIME) != 0)
DHerr(DH_F_DH_CHECK_EX, DH_R_CHECK_P_NOT_PRIME);
if ((errflags & DH_CHECK_P_NOT_SAFE_PRIME) != 0)
DHerr(DH_F_DH_CHECK_EX, DH_R_CHECK_P_NOT_SAFE_PRIME);
if ((errflags & DH_MODULUS_TOO_SMALL) != 0)
DHerr(DH_F_DH_CHECK_EX, DH_R_MODULUS_TOO_SMALL);
if ((errflags & DH_MODULUS_TOO_LARGE) != 0)
DHerr(DH_F_DH_CHECK_EX, DH_R_MODULUS_TOO_LARGE);
return errflags == 0;
}
/* Note: according to documentation - this only checks the params */
int DH_check(const DH *dh, int *ret)
{
#ifdef FIPS_MODE
return DH_check_params(dh, ret);
#else
int ok = 0, r;
BN_CTX *ctx = NULL;
BIGNUM *t1 = NULL, *t2 = NULL;
int nid = DH_get_nid((DH *)dh);
*ret = 0;
if (nid != NID_undef)
return 1;
if (!DH_check_params(dh, ret))
return 0;
ctx = BN_CTX_new();
if (ctx == NULL)
goto err;
BN_CTX_start(ctx);
t1 = BN_CTX_get(ctx);
t2 = BN_CTX_get(ctx);
if (t2 == NULL)
goto err;
if (dh->params.q != NULL) {
if (BN_cmp(dh->params.g, BN_value_one()) <= 0)
*ret |= DH_NOT_SUITABLE_GENERATOR;
else if (BN_cmp(dh->params.g, dh->params.p) >= 0)
*ret |= DH_NOT_SUITABLE_GENERATOR;
else {
/* Check g^q == 1 mod p */
if (!BN_mod_exp(t1, dh->params.g, dh->params.q, dh->params.p, ctx))
goto err;
if (!BN_is_one(t1))
*ret |= DH_NOT_SUITABLE_GENERATOR;
}
r = BN_check_prime(dh->params.q, ctx, NULL);
if (r < 0)
goto err;
if (!r)
*ret |= DH_CHECK_Q_NOT_PRIME;
/* Check p == 1 mod q i.e. q divides p - 1 */
if (!BN_div(t1, t2, dh->params.p, dh->params.q, ctx))
goto err;
if (!BN_is_one(t2))
*ret |= DH_CHECK_INVALID_Q_VALUE;
if (dh->params.j != NULL
&& BN_cmp(dh->params.j, t1))
*ret |= DH_CHECK_INVALID_J_VALUE;
}
r = BN_check_prime(dh->params.p, ctx, NULL);
if (r < 0)
goto err;
if (!r)
*ret |= DH_CHECK_P_NOT_PRIME;
else if (dh->params.q == NULL) {
if (!BN_rshift1(t1, dh->params.p))
goto err;
r = BN_check_prime(t1, ctx, NULL);
if (r < 0)
goto err;
if (!r)
*ret |= DH_CHECK_P_NOT_SAFE_PRIME;
}
ok = 1;
err:
BN_CTX_end(ctx);
BN_CTX_free(ctx);
return ok;
#endif /* FIPS_MODE */
}
int DH_check_pub_key_ex(const DH *dh, const BIGNUM *pub_key)
{
int errflags = 0;
if (!DH_check_pub_key(dh, pub_key, &errflags))
return 0;
if ((errflags & DH_CHECK_PUBKEY_TOO_SMALL) != 0)
DHerr(DH_F_DH_CHECK_PUB_KEY_EX, DH_R_CHECK_PUBKEY_TOO_SMALL);
if ((errflags & DH_CHECK_PUBKEY_TOO_LARGE) != 0)
DHerr(DH_F_DH_CHECK_PUB_KEY_EX, DH_R_CHECK_PUBKEY_TOO_LARGE);
if ((errflags & DH_CHECK_PUBKEY_INVALID) != 0)
DHerr(DH_F_DH_CHECK_PUB_KEY_EX, DH_R_CHECK_PUBKEY_INVALID);
return errflags == 0;
}
/*
* See SP800-56Ar3 Section 5.6.2.3.1 : FFC Full public key validation.
*/
int DH_check_pub_key(const DH *dh, const BIGNUM *pub_key, int *ret)
{
return ffc_validate_public_key(&dh->params, pub_key, ret);
}
/*
* See SP800-56Ar3 Section 5.6.2.3.1 : FFC Partial public key validation.
* To only be used with ephemeral FFC public keys generated using the approved
* safe-prime groups.
*/
int dh_check_pub_key_partial(const DH *dh, const BIGNUM *pub_key, int *ret)
{
return ffc_validate_public_key_partial(&dh->params, pub_key, ret);
}
int dh_check_priv_key(const DH *dh, const BIGNUM *priv_key, int *ret)
{
int ok = 0;
BIGNUM *two_powN = NULL, *upper;
*ret = 0;
two_powN = BN_new();
if (two_powN == NULL)
return 0;
if (dh->params.q == NULL)
goto err;
upper = dh->params.q;
/* Is it from an approved Safe prime group ?*/
if (DH_get_nid((DH *)dh) != NID_undef) {
if (!BN_lshift(two_powN, BN_value_one(), dh->length))
goto err;
if (BN_cmp(two_powN, dh->params.q) < 0)
upper = two_powN;
}
if (!ffc_validate_private_key(upper, priv_key, ret))
goto err;
ok = 1;
err:
BN_free(two_powN);
return ok;
}
/*
* FFC pairwise check from SP800-56A R3.
* Section 5.6.2.1.4 Owner Assurance of Pair-wise Consistency
*/
int dh_check_pairwise(DH *dh)
{
int ret = 0;
BN_CTX *ctx = NULL;
BIGNUM *pub_key = NULL;
if (dh->params.p == NULL
|| dh->params.g == NULL
|| dh->priv_key == NULL
|| dh->pub_key == NULL)
return 0;
ctx = BN_CTX_new_ex(dh->libctx);
if (ctx == NULL)
goto err;
pub_key = BN_new();
if (pub_key == NULL)
goto err;
/* recalculate the public key = (g ^ priv) mod p */
if (!dh_generate_public_key(ctx, dh, dh->priv_key, pub_key))
goto err;
/* check it matches the existing pubic_key */
ret = BN_cmp(pub_key, dh->pub_key) == 0;
err:
BN_free(pub_key);
BN_CTX_free(ctx);
return ret;
}
|
