1 /* ====================================================================
2 * Copyright (c) 2011 The OpenSSL Project. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 *
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in
13 * the documentation and/or other materials provided with the
14 * distribution.
15 *
16 * 3. All advertising materials mentioning features or use of this
17 * software must display the following acknowledgment:
18 * "This product includes software developed by the OpenSSL Project
19 * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
20 *
21 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
22 * endorse or promote products derived from this software without
23 * prior written permission. For written permission, please contact
24 * licensing@OpenSSL.org.
25 *
26 * 5. Products derived from this software may not be called "OpenSSL"
27 * nor may "OpenSSL" appear in their names without prior written
28 * permission of the OpenSSL Project.
29 *
30 * 6. Redistributions of any form whatsoever must retain the following
31 * acknowledgment:
32 * "This product includes software developed by the OpenSSL Project
33 * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
34 *
35 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
36 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
37 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
38 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
39 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
40 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
41 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
42 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
43 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
44 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
45 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
46 * OF THE POSSIBILITY OF SUCH DAMAGE.
47 * ====================================================================
48 *
49 * This product includes cryptographic software written by Eric Young
50 * (eay@cryptsoft.com). This product includes software written by Tim
51 * Hudson (tjh@cryptsoft.com). */
52
53 #include <openssl/dh.h>
54
55 #include <openssl/bn.h>
56 #include <openssl/err.h>
57 #include <openssl/mem.h>
58
59 #include "../fipsmodule/bn/internal.h"
60
61
BN_get_rfc3526_prime_1536(BIGNUM * ret)62 BIGNUM *BN_get_rfc3526_prime_1536(BIGNUM *ret) {
63 static const BN_ULONG kPrime1536Data[] = {
64 TOBN(0xffffffff, 0xffffffff), TOBN(0xf1746c08, 0xca237327),
65 TOBN(0x670c354e, 0x4abc9804), TOBN(0x9ed52907, 0x7096966d),
66 TOBN(0x1c62f356, 0x208552bb), TOBN(0x83655d23, 0xdca3ad96),
67 TOBN(0x69163fa8, 0xfd24cf5f), TOBN(0x98da4836, 0x1c55d39a),
68 TOBN(0xc2007cb8, 0xa163bf05), TOBN(0x49286651, 0xece45b3d),
69 TOBN(0xae9f2411, 0x7c4b1fe6), TOBN(0xee386bfb, 0x5a899fa5),
70 TOBN(0x0bff5cb6, 0xf406b7ed), TOBN(0xf44c42e9, 0xa637ed6b),
71 TOBN(0xe485b576, 0x625e7ec6), TOBN(0x4fe1356d, 0x6d51c245),
72 TOBN(0x302b0a6d, 0xf25f1437), TOBN(0xef9519b3, 0xcd3a431b),
73 TOBN(0x514a0879, 0x8e3404dd), TOBN(0x020bbea6, 0x3b139b22),
74 TOBN(0x29024e08, 0x8a67cc74), TOBN(0xc4c6628b, 0x80dc1cd1),
75 TOBN(0xc90fdaa2, 0x2168c234), TOBN(0xffffffff, 0xffffffff),
76 };
77
78 static const BIGNUM kPrime1536BN = STATIC_BIGNUM(kPrime1536Data);
79
80 BIGNUM *alloc = NULL;
81 if (ret == NULL) {
82 alloc = BN_new();
83 if (alloc == NULL) {
84 return NULL;
85 }
86 ret = alloc;
87 }
88
89 if (!BN_copy(ret, &kPrime1536BN)) {
90 BN_free(alloc);
91 return NULL;
92 }
93
94 return ret;
95 }
96
DH_generate_parameters_ex(DH * dh,int prime_bits,int generator,BN_GENCB * cb)97 int DH_generate_parameters_ex(DH *dh, int prime_bits, int generator,
98 BN_GENCB *cb) {
99 // We generate DH parameters as follows
100 // find a prime q which is prime_bits/2 bits long.
101 // p=(2*q)+1 or (p-1)/2 = q
102 // For this case, g is a generator if
103 // g^((p-1)/q) mod p != 1 for values of q which are the factors of p-1.
104 // Since the factors of p-1 are q and 2, we just need to check
105 // g^2 mod p != 1 and g^q mod p != 1.
106 //
107 // Having said all that,
108 // there is another special case method for the generators 2, 3 and 5.
109 // for 2, p mod 24 == 11
110 // for 3, p mod 12 == 5 <<<<< does not work for safe primes.
111 // for 5, p mod 10 == 3 or 7
112 //
113 // Thanks to Phil Karn <karn@qualcomm.com> for the pointers about the
114 // special generators and for answering some of my questions.
115 //
116 // I've implemented the second simple method :-).
117 // Since DH should be using a safe prime (both p and q are prime),
118 // this generator function can take a very very long time to run.
119
120 // Actually there is no reason to insist that 'generator' be a generator.
121 // It's just as OK (and in some sense better) to use a generator of the
122 // order-q subgroup.
123
124 BIGNUM *t1, *t2;
125 int g, ok = 0;
126 BN_CTX *ctx = NULL;
127
128 ctx = BN_CTX_new();
129 if (ctx == NULL) {
130 goto err;
131 }
132 BN_CTX_start(ctx);
133 t1 = BN_CTX_get(ctx);
134 t2 = BN_CTX_get(ctx);
135 if (t1 == NULL || t2 == NULL) {
136 goto err;
137 }
138
139 // Make sure |dh| has the necessary elements
140 if (dh->p == NULL) {
141 dh->p = BN_new();
142 if (dh->p == NULL) {
143 goto err;
144 }
145 }
146 if (dh->g == NULL) {
147 dh->g = BN_new();
148 if (dh->g == NULL) {
149 goto err;
150 }
151 }
152
153 if (generator <= 1) {
154 OPENSSL_PUT_ERROR(DH, DH_R_BAD_GENERATOR);
155 goto err;
156 }
157 if (generator == DH_GENERATOR_2) {
158 if (!BN_set_word(t1, 24)) {
159 goto err;
160 }
161 if (!BN_set_word(t2, 11)) {
162 goto err;
163 }
164 g = 2;
165 } else if (generator == DH_GENERATOR_5) {
166 if (!BN_set_word(t1, 10)) {
167 goto err;
168 }
169 if (!BN_set_word(t2, 3)) {
170 goto err;
171 }
172 // BN_set_word(t3,7); just have to miss
173 // out on these ones :-(
174 g = 5;
175 } else {
176 // in the general case, don't worry if 'generator' is a
177 // generator or not: since we are using safe primes,
178 // it will generate either an order-q or an order-2q group,
179 // which both is OK
180 if (!BN_set_word(t1, 2)) {
181 goto err;
182 }
183 if (!BN_set_word(t2, 1)) {
184 goto err;
185 }
186 g = generator;
187 }
188
189 if (!BN_generate_prime_ex(dh->p, prime_bits, 1, t1, t2, cb)) {
190 goto err;
191 }
192 if (!BN_GENCB_call(cb, 3, 0)) {
193 goto err;
194 }
195 if (!BN_set_word(dh->g, g)) {
196 goto err;
197 }
198 ok = 1;
199
200 err:
201 if (!ok) {
202 OPENSSL_PUT_ERROR(DH, ERR_R_BN_LIB);
203 }
204
205 if (ctx != NULL) {
206 BN_CTX_end(ctx);
207 BN_CTX_free(ctx);
208 }
209 return ok;
210 }
211
int_dh_bn_cpy(BIGNUM ** dst,const BIGNUM * src)212 static int int_dh_bn_cpy(BIGNUM **dst, const BIGNUM *src) {
213 BIGNUM *a = NULL;
214
215 if (src) {
216 a = BN_dup(src);
217 if (!a) {
218 return 0;
219 }
220 }
221
222 BN_free(*dst);
223 *dst = a;
224 return 1;
225 }
226
int_dh_param_copy(DH * to,const DH * from,int is_x942)227 static int int_dh_param_copy(DH *to, const DH *from, int is_x942) {
228 if (is_x942 == -1) {
229 is_x942 = !!from->q;
230 }
231 if (!int_dh_bn_cpy(&to->p, from->p) ||
232 !int_dh_bn_cpy(&to->g, from->g)) {
233 return 0;
234 }
235
236 if (!is_x942) {
237 return 1;
238 }
239
240 if (!int_dh_bn_cpy(&to->q, from->q) ||
241 !int_dh_bn_cpy(&to->j, from->j)) {
242 return 0;
243 }
244
245 OPENSSL_free(to->seed);
246 to->seed = NULL;
247 to->seedlen = 0;
248
249 if (from->seed) {
250 to->seed = OPENSSL_memdup(from->seed, from->seedlen);
251 if (!to->seed) {
252 return 0;
253 }
254 to->seedlen = from->seedlen;
255 }
256
257 return 1;
258 }
259
DHparams_dup(const DH * dh)260 DH *DHparams_dup(const DH *dh) {
261 DH *ret = DH_new();
262 if (!ret) {
263 return NULL;
264 }
265
266 if (!int_dh_param_copy(ret, dh, -1)) {
267 DH_free(ret);
268 return NULL;
269 }
270
271 return ret;
272 }
273