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58964a49 | 1 | /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) |
d02b48c6 RE |
2 | * All rights reserved. |
3 | * | |
4 | * This package is an SSL implementation written | |
5 | * by Eric Young (eay@cryptsoft.com). | |
6 | * The implementation was written so as to conform with Netscapes SSL. | |
0f113f3e | 7 | * |
d02b48c6 RE |
8 | * This library is free for commercial and non-commercial use as long as |
9 | * the following conditions are aheared to. The following conditions | |
10 | * apply to all code found in this distribution, be it the RC4, RSA, | |
11 | * lhash, DES, etc., code; not just the SSL code. The SSL documentation | |
12 | * included with this distribution is covered by the same copyright terms | |
13 | * except that the holder is Tim Hudson (tjh@cryptsoft.com). | |
0f113f3e | 14 | * |
d02b48c6 RE |
15 | * Copyright remains Eric Young's, and as such any Copyright notices in |
16 | * the code are not to be removed. | |
17 | * If this package is used in a product, Eric Young should be given attribution | |
18 | * as the author of the parts of the library used. | |
19 | * This can be in the form of a textual message at program startup or | |
20 | * in documentation (online or textual) provided with the package. | |
0f113f3e | 21 | * |
d02b48c6 RE |
22 | * Redistribution and use in source and binary forms, with or without |
23 | * modification, are permitted provided that the following conditions | |
24 | * are met: | |
25 | * 1. Redistributions of source code must retain the copyright | |
26 | * notice, this list of conditions and the following disclaimer. | |
27 | * 2. Redistributions in binary form must reproduce the above copyright | |
28 | * notice, this list of conditions and the following disclaimer in the | |
29 | * documentation and/or other materials provided with the distribution. | |
30 | * 3. All advertising materials mentioning features or use of this software | |
31 | * must display the following acknowledgement: | |
32 | * "This product includes cryptographic software written by | |
33 | * Eric Young (eay@cryptsoft.com)" | |
34 | * The word 'cryptographic' can be left out if the rouines from the library | |
35 | * being used are not cryptographic related :-). | |
0f113f3e | 36 | * 4. If you include any Windows specific code (or a derivative thereof) from |
d02b48c6 RE |
37 | * the apps directory (application code) you must include an acknowledgement: |
38 | * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" | |
0f113f3e | 39 | * |
d02b48c6 RE |
40 | * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND |
41 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
42 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
43 | * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE | |
44 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
45 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
46 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
47 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
48 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
49 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
50 | * SUCH DAMAGE. | |
0f113f3e | 51 | * |
d02b48c6 RE |
52 | * The licence and distribution terms for any publically available version or |
53 | * derivative of this code cannot be changed. i.e. this code cannot simply be | |
54 | * copied and put under another distribution licence | |
55 | * [including the GNU Public Licence.] | |
56 | */ | |
57 | ||
58 | #include <stdio.h> | |
b39fc560 | 59 | #include "internal/cryptlib.h" |
ec577822 BM |
60 | #include <openssl/rand.h> |
61 | #include <openssl/dh.h> | |
829ccf6a | 62 | #include "internal/bn_int.h" |
d02b48c6 | 63 | |
13066cee | 64 | static int generate_key(DH *dh); |
f971ccb2 RL |
65 | static int compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh); |
66 | static int dh_bn_mod_exp(const DH *dh, BIGNUM *r, | |
0f113f3e MC |
67 | const BIGNUM *a, const BIGNUM *p, |
68 | const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx); | |
13066cee DSH |
69 | static int dh_init(DH *dh); |
70 | static int dh_finish(DH *dh); | |
71 | ||
6b691a5c | 72 | int DH_generate_key(DH *dh) |
0f113f3e MC |
73 | { |
74 | return dh->meth->generate_key(dh); | |
75 | } | |
13066cee | 76 | |
f971ccb2 | 77 | int DH_compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh) |
0f113f3e MC |
78 | { |
79 | return dh->meth->compute_key(key, pub_key, dh); | |
80 | } | |
13066cee | 81 | |
bc91494e | 82 | int DH_compute_key_padded(unsigned char *key, const BIGNUM *pub_key, DH *dh) |
0f113f3e MC |
83 | { |
84 | int rv, pad; | |
85 | rv = dh->meth->compute_key(key, pub_key, dh); | |
86 | if (rv <= 0) | |
87 | return rv; | |
88 | pad = BN_num_bytes(dh->p) - rv; | |
89 | if (pad > 0) { | |
90 | memmove(key + pad, key, rv); | |
91 | memset(key, 0, pad); | |
92 | } | |
93 | return rv + pad; | |
94 | } | |
bc91494e | 95 | |
13066cee | 96 | static DH_METHOD dh_ossl = { |
0f113f3e MC |
97 | "OpenSSL DH Method", |
98 | generate_key, | |
99 | compute_key, | |
100 | dh_bn_mod_exp, | |
101 | dh_init, | |
102 | dh_finish, | |
103 | DH_FLAG_FIPS_METHOD, | |
104 | NULL, | |
105 | NULL | |
13066cee DSH |
106 | }; |
107 | ||
f971ccb2 | 108 | const DH_METHOD *DH_OpenSSL(void) |
13066cee | 109 | { |
0f113f3e | 110 | return &dh_ossl; |
13066cee DSH |
111 | } |
112 | ||
113 | static int generate_key(DH *dh) | |
0f113f3e MC |
114 | { |
115 | int ok = 0; | |
116 | int generate_new_key = 0; | |
117 | unsigned l; | |
118 | BN_CTX *ctx; | |
119 | BN_MONT_CTX *mont = NULL; | |
120 | BIGNUM *pub_key = NULL, *priv_key = NULL; | |
d02b48c6 | 121 | |
0f113f3e MC |
122 | ctx = BN_CTX_new(); |
123 | if (ctx == NULL) | |
124 | goto err; | |
d02b48c6 | 125 | |
0f113f3e | 126 | if (dh->priv_key == NULL) { |
74924dcb | 127 | priv_key = BN_secure_new(); |
0f113f3e MC |
128 | if (priv_key == NULL) |
129 | goto err; | |
130 | generate_new_key = 1; | |
131 | } else | |
132 | priv_key = dh->priv_key; | |
d02b48c6 | 133 | |
0f113f3e MC |
134 | if (dh->pub_key == NULL) { |
135 | pub_key = BN_new(); | |
136 | if (pub_key == NULL) | |
137 | goto err; | |
138 | } else | |
139 | pub_key = dh->pub_key; | |
d02b48c6 | 140 | |
0f113f3e MC |
141 | if (dh->flags & DH_FLAG_CACHE_MONT_P) { |
142 | mont = BN_MONT_CTX_set_locked(&dh->method_mont_p, | |
143 | CRYPTO_LOCK_DH, dh->p, ctx); | |
144 | if (!mont) | |
145 | goto err; | |
146 | } | |
6ec8e63a | 147 | |
0f113f3e MC |
148 | if (generate_new_key) { |
149 | if (dh->q) { | |
150 | do { | |
151 | if (!BN_rand_range(priv_key, dh->q)) | |
152 | goto err; | |
153 | } | |
154 | while (BN_is_zero(priv_key) || BN_is_one(priv_key)); | |
155 | } else { | |
156 | /* secret exponent length */ | |
157 | l = dh->length ? dh->length : BN_num_bits(dh->p) - 1; | |
158 | if (!BN_rand(priv_key, l, 0, 0)) | |
159 | goto err; | |
160 | } | |
161 | } | |
dfeab068 | 162 | |
0f113f3e MC |
163 | { |
164 | BIGNUM *local_prk = NULL; | |
165 | BIGNUM *prk; | |
46a64376 | 166 | |
0f113f3e MC |
167 | if ((dh->flags & DH_FLAG_NO_EXP_CONSTTIME) == 0) { |
168 | local_prk = prk = BN_new(); | |
90945fa3 MC |
169 | if (local_prk == NULL) |
170 | goto err; | |
0f113f3e | 171 | BN_with_flags(prk, priv_key, BN_FLG_CONSTTIME); |
fd7d2520 | 172 | } else { |
0f113f3e | 173 | prk = priv_key; |
fd7d2520 | 174 | } |
46a64376 | 175 | |
0f113f3e | 176 | if (!dh->meth->bn_mod_exp(dh, pub_key, dh->g, prk, dh->p, ctx, mont)) { |
23a1d5e9 | 177 | BN_free(local_prk); |
0f113f3e MC |
178 | goto err; |
179 | } | |
fd7d2520 | 180 | /* We MUST free local_prk before any further use of priv_key */ |
23a1d5e9 | 181 | BN_free(local_prk); |
0f113f3e | 182 | } |
46a64376 | 183 | |
0f113f3e MC |
184 | dh->pub_key = pub_key; |
185 | dh->priv_key = priv_key; | |
186 | ok = 1; | |
187 | err: | |
188 | if (ok != 1) | |
189 | DHerr(DH_F_GENERATE_KEY, ERR_R_BN_LIB); | |
d02b48c6 | 190 | |
23a1d5e9 | 191 | if (pub_key != dh->pub_key) |
0f113f3e | 192 | BN_free(pub_key); |
23a1d5e9 | 193 | if (priv_key != dh->priv_key) |
0f113f3e MC |
194 | BN_free(priv_key); |
195 | BN_CTX_free(ctx); | |
196 | return (ok); | |
197 | } | |
d02b48c6 | 198 | |
f971ccb2 | 199 | static int compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh) |
0f113f3e MC |
200 | { |
201 | BN_CTX *ctx = NULL; | |
202 | BN_MONT_CTX *mont = NULL; | |
203 | BIGNUM *tmp; | |
204 | int ret = -1; | |
205 | int check_result; | |
d02b48c6 | 206 | |
0f113f3e MC |
207 | if (BN_num_bits(dh->p) > OPENSSL_DH_MAX_MODULUS_BITS) { |
208 | DHerr(DH_F_COMPUTE_KEY, DH_R_MODULUS_TOO_LARGE); | |
209 | goto err; | |
210 | } | |
5e3225cc | 211 | |
0f113f3e MC |
212 | ctx = BN_CTX_new(); |
213 | if (ctx == NULL) | |
214 | goto err; | |
215 | BN_CTX_start(ctx); | |
216 | tmp = BN_CTX_get(ctx); | |
6ec8e63a | 217 | |
0f113f3e MC |
218 | if (dh->priv_key == NULL) { |
219 | DHerr(DH_F_COMPUTE_KEY, DH_R_NO_PRIVATE_VALUE); | |
220 | goto err; | |
221 | } | |
dfeab068 | 222 | |
0f113f3e MC |
223 | if (dh->flags & DH_FLAG_CACHE_MONT_P) { |
224 | mont = BN_MONT_CTX_set_locked(&dh->method_mont_p, | |
225 | CRYPTO_LOCK_DH, dh->p, ctx); | |
226 | if ((dh->flags & DH_FLAG_NO_EXP_CONSTTIME) == 0) { | |
227 | /* XXX */ | |
228 | BN_set_flags(dh->priv_key, BN_FLG_CONSTTIME); | |
229 | } | |
230 | if (!mont) | |
231 | goto err; | |
232 | } | |
bf3d6c0c | 233 | |
0f113f3e MC |
234 | if (!DH_check_pub_key(dh, pub_key, &check_result) || check_result) { |
235 | DHerr(DH_F_COMPUTE_KEY, DH_R_INVALID_PUBKEY); | |
236 | goto err; | |
237 | } | |
d02b48c6 | 238 | |
0f113f3e MC |
239 | if (!dh-> |
240 | meth->bn_mod_exp(dh, tmp, pub_key, dh->priv_key, dh->p, ctx, mont)) { | |
241 | DHerr(DH_F_COMPUTE_KEY, ERR_R_BN_LIB); | |
242 | goto err; | |
243 | } | |
13066cee | 244 | |
0f113f3e MC |
245 | ret = BN_bn2bin(tmp, key); |
246 | err: | |
247 | if (ctx != NULL) { | |
248 | BN_CTX_end(ctx); | |
249 | BN_CTX_free(ctx); | |
250 | } | |
251 | return (ret); | |
252 | } | |
6dad7bd6 | 253 | |
0f113f3e MC |
254 | static int dh_bn_mod_exp(const DH *dh, BIGNUM *r, |
255 | const BIGNUM *a, const BIGNUM *p, | |
256 | const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx) | |
257 | { | |
258 | /* | |
259 | * If a is only one word long and constant time is false, use the faster | |
260 | * exponenentiation function. | |
261 | */ | |
262 | if (bn_get_top(a) == 1 && ((dh->flags & DH_FLAG_NO_EXP_CONSTTIME) != 0)) { | |
263 | BN_ULONG A = bn_get_words(a)[0]; | |
264 | return BN_mod_exp_mont_word(r, A, p, m, ctx, m_ctx); | |
265 | } else | |
266 | return BN_mod_exp_mont(r, a, p, m, ctx, m_ctx); | |
267 | } | |
13066cee DSH |
268 | |
269 | static int dh_init(DH *dh) | |
0f113f3e MC |
270 | { |
271 | dh->flags |= DH_FLAG_CACHE_MONT_P; | |
272 | return (1); | |
273 | } | |
13066cee DSH |
274 | |
275 | static int dh_finish(DH *dh) | |
0f113f3e | 276 | { |
23a1d5e9 | 277 | BN_MONT_CTX_free(dh->method_mont_p); |
0f113f3e MC |
278 | return (1); |
279 | } |