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d02b48c6 | 1 | /* crypto/dh/dh_key.c */ |
58964a49 | 2 | /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) |
d02b48c6 RE |
3 | * All rights reserved. |
4 | * | |
5 | * This package is an SSL implementation written | |
6 | * by Eric Young (eay@cryptsoft.com). | |
7 | * The implementation was written so as to conform with Netscapes SSL. | |
8 | * | |
9 | * This library is free for commercial and non-commercial use as long as | |
10 | * the following conditions are aheared to. The following conditions | |
11 | * apply to all code found in this distribution, be it the RC4, RSA, | |
12 | * lhash, DES, etc., code; not just the SSL code. The SSL documentation | |
13 | * included with this distribution is covered by the same copyright terms | |
14 | * except that the holder is Tim Hudson (tjh@cryptsoft.com). | |
15 | * | |
16 | * Copyright remains Eric Young's, and as such any Copyright notices in | |
17 | * the code are not to be removed. | |
18 | * If this package is used in a product, Eric Young should be given attribution | |
19 | * as the author of the parts of the library used. | |
20 | * This can be in the form of a textual message at program startup or | |
21 | * in documentation (online or textual) provided with the package. | |
22 | * | |
23 | * Redistribution and use in source and binary forms, with or without | |
24 | * modification, are permitted provided that the following conditions | |
25 | * are met: | |
26 | * 1. Redistributions of source code must retain the copyright | |
27 | * notice, this list of conditions and the following disclaimer. | |
28 | * 2. Redistributions in binary form must reproduce the above copyright | |
29 | * notice, this list of conditions and the following disclaimer in the | |
30 | * documentation and/or other materials provided with the distribution. | |
31 | * 3. All advertising materials mentioning features or use of this software | |
32 | * must display the following acknowledgement: | |
33 | * "This product includes cryptographic software written by | |
34 | * Eric Young (eay@cryptsoft.com)" | |
35 | * The word 'cryptographic' can be left out if the rouines from the library | |
36 | * being used are not cryptographic related :-). | |
37 | * 4. If you include any Windows specific code (or a derivative thereof) from | |
38 | * the apps directory (application code) you must include an acknowledgement: | |
39 | * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" | |
40 | * | |
41 | * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND | |
42 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
43 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
44 | * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE | |
45 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
46 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
47 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
48 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
49 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
50 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
51 | * SUCH DAMAGE. | |
52 | * | |
53 | * The licence and distribution terms for any publically available version or | |
54 | * derivative of this code cannot be changed. i.e. this code cannot simply be | |
55 | * copied and put under another distribution licence | |
56 | * [including the GNU Public Licence.] | |
57 | */ | |
58 | ||
14ae26f2 DSH |
59 | #define OPENSSL_FIPSAPI |
60 | ||
d02b48c6 RE |
61 | #include <stdio.h> |
62 | #include "cryptlib.h" | |
ec577822 BM |
63 | #include <openssl/bn.h> |
64 | #include <openssl/rand.h> | |
65 | #include <openssl/dh.h> | |
83c3410b DSH |
66 | #ifdef OPENSSL_FIPS |
67 | #include <openssl/fips.h> | |
68 | #endif | |
d02b48c6 | 69 | |
13066cee | 70 | static int generate_key(DH *dh); |
f971ccb2 RL |
71 | static int compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh); |
72 | static int dh_bn_mod_exp(const DH *dh, BIGNUM *r, | |
73 | const BIGNUM *a, const BIGNUM *p, | |
13066cee DSH |
74 | const BIGNUM *m, BN_CTX *ctx, |
75 | BN_MONT_CTX *m_ctx); | |
76 | static int dh_init(DH *dh); | |
77 | static int dh_finish(DH *dh); | |
78 | ||
6b691a5c | 79 | int DH_generate_key(DH *dh) |
13066cee | 80 | { |
cb78486d | 81 | return dh->meth->generate_key(dh); |
13066cee DSH |
82 | } |
83 | ||
f971ccb2 | 84 | int DH_compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh) |
13066cee | 85 | { |
cb78486d | 86 | return dh->meth->compute_key(key, pub_key, dh); |
13066cee DSH |
87 | } |
88 | ||
89 | static DH_METHOD dh_ossl = { | |
90 | "OpenSSL DH Method", | |
91 | generate_key, | |
92 | compute_key, | |
93 | dh_bn_mod_exp, | |
94 | dh_init, | |
95 | dh_finish, | |
96 | 0, | |
0e4aa0d2 | 97 | NULL, |
13066cee DSH |
98 | NULL |
99 | }; | |
100 | ||
f971ccb2 | 101 | const DH_METHOD *DH_OpenSSL(void) |
13066cee DSH |
102 | { |
103 | return &dh_ossl; | |
104 | } | |
105 | ||
106 | static int generate_key(DH *dh) | |
d02b48c6 RE |
107 | { |
108 | int ok=0; | |
924875e5 | 109 | int generate_new_key=0; |
6aecef81 | 110 | unsigned l; |
c62b26fd | 111 | BN_CTX *ctx; |
3cc54008 | 112 | BN_MONT_CTX *mont=NULL; |
d02b48c6 RE |
113 | BIGNUM *pub_key=NULL,*priv_key=NULL; |
114 | ||
83c3410b DSH |
115 | #ifdef OPENSSL_FIPS |
116 | if (FIPS_mode() && (BN_num_bits(dh->p) < OPENSSL_DH_FIPS_MIN_MODULUS_BITS)) | |
117 | { | |
118 | DHerr(DH_F_GENERATE_KEY, DH_R_KEY_SIZE_TOO_SMALL); | |
119 | return 0; | |
120 | } | |
121 | #endif | |
122 | ||
c62b26fd BM |
123 | ctx = BN_CTX_new(); |
124 | if (ctx == NULL) goto err; | |
d02b48c6 RE |
125 | |
126 | if (dh->priv_key == NULL) | |
127 | { | |
d02b48c6 RE |
128 | priv_key=BN_new(); |
129 | if (priv_key == NULL) goto err; | |
924875e5 | 130 | generate_new_key=1; |
d02b48c6 RE |
131 | } |
132 | else | |
133 | priv_key=dh->priv_key; | |
134 | ||
135 | if (dh->pub_key == NULL) | |
136 | { | |
137 | pub_key=BN_new(); | |
138 | if (pub_key == NULL) goto err; | |
139 | } | |
140 | else | |
141 | pub_key=dh->pub_key; | |
142 | ||
6ec8e63a DSH |
143 | |
144 | if (dh->flags & DH_FLAG_CACHE_MONT_P) | |
dfeab068 | 145 | { |
879b1980 | 146 | mont = BN_MONT_CTX_set_locked(&dh->method_mont_p, |
6ec8e63a DSH |
147 | CRYPTO_LOCK_DH, dh->p, ctx); |
148 | if (!mont) | |
149 | goto err; | |
dfeab068 | 150 | } |
dfeab068 | 151 | |
924875e5 BM |
152 | if (generate_new_key) |
153 | { | |
de3333ba | 154 | l = dh->length ? dh->length : BN_num_bits(dh->p)-1; /* secret exponent length */ |
924875e5 BM |
155 | if (!BN_rand(priv_key, l, 0, 0)) goto err; |
156 | } | |
46a64376 BM |
157 | |
158 | { | |
159 | BIGNUM local_prk; | |
160 | BIGNUM *prk; | |
161 | ||
162 | if ((dh->flags & DH_FLAG_NO_EXP_CONSTTIME) == 0) | |
163 | { | |
a28a5d9c | 164 | BN_init(&local_prk); |
46a64376 | 165 | prk = &local_prk; |
bd31fb21 | 166 | BN_with_flags(prk, priv_key, BN_FLG_CONSTTIME); |
46a64376 BM |
167 | } |
168 | else | |
169 | prk = priv_key; | |
170 | ||
171 | if (!dh->meth->bn_mod_exp(dh, pub_key, dh->g, prk, dh->p, ctx, mont)) goto err; | |
172 | } | |
d02b48c6 RE |
173 | |
174 | dh->pub_key=pub_key; | |
175 | dh->priv_key=priv_key; | |
176 | ok=1; | |
177 | err: | |
178 | if (ok != 1) | |
aa4ce731 | 179 | DHerr(DH_F_GENERATE_KEY,ERR_R_BN_LIB); |
d02b48c6 RE |
180 | |
181 | if ((pub_key != NULL) && (dh->pub_key == NULL)) BN_free(pub_key); | |
182 | if ((priv_key != NULL) && (dh->priv_key == NULL)) BN_free(priv_key); | |
c62b26fd | 183 | BN_CTX_free(ctx); |
d02b48c6 RE |
184 | return(ok); |
185 | } | |
186 | ||
f971ccb2 | 187 | static int compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh) |
d02b48c6 | 188 | { |
c2cccfc5 | 189 | BN_CTX *ctx=NULL; |
3cc54008 | 190 | BN_MONT_CTX *mont=NULL; |
d02b48c6 RE |
191 | BIGNUM *tmp; |
192 | int ret= -1; | |
bf3d6c0c | 193 | int check_result; |
d02b48c6 | 194 | |
5e3225cc BM |
195 | if (BN_num_bits(dh->p) > OPENSSL_DH_MAX_MODULUS_BITS) |
196 | { | |
197 | DHerr(DH_F_COMPUTE_KEY,DH_R_MODULUS_TOO_LARGE); | |
198 | goto err; | |
199 | } | |
200 | ||
83c3410b DSH |
201 | #ifdef OPENSSL_FIPS |
202 | if (FIPS_mode() && (BN_num_bits(dh->p) < OPENSSL_DH_FIPS_MIN_MODULUS_BITS)) | |
203 | { | |
204 | DHerr(DH_F_COMPUTE_KEY, DH_R_KEY_SIZE_TOO_SMALL); | |
205 | goto err; | |
206 | } | |
207 | #endif | |
208 | ||
c62b26fd BM |
209 | ctx = BN_CTX_new(); |
210 | if (ctx == NULL) goto err; | |
211 | BN_CTX_start(ctx); | |
212 | tmp = BN_CTX_get(ctx); | |
d02b48c6 RE |
213 | |
214 | if (dh->priv_key == NULL) | |
215 | { | |
aa4ce731 | 216 | DHerr(DH_F_COMPUTE_KEY,DH_R_NO_PRIVATE_VALUE); |
d02b48c6 RE |
217 | goto err; |
218 | } | |
6ec8e63a DSH |
219 | |
220 | if (dh->flags & DH_FLAG_CACHE_MONT_P) | |
dfeab068 | 221 | { |
879b1980 | 222 | mont = BN_MONT_CTX_set_locked(&dh->method_mont_p, |
6ec8e63a | 223 | CRYPTO_LOCK_DH, dh->p, ctx); |
46a64376 BM |
224 | if ((dh->flags & DH_FLAG_NO_EXP_CONSTTIME) == 0) |
225 | { | |
226 | /* XXX */ | |
bd31fb21 | 227 | BN_set_flags(dh->priv_key, BN_FLG_CONSTTIME); |
46a64376 | 228 | } |
6ec8e63a DSH |
229 | if (!mont) |
230 | goto err; | |
dfeab068 RE |
231 | } |
232 | ||
bf3d6c0c BL |
233 | if (!DH_check_pub_key(dh, pub_key, &check_result) || check_result) |
234 | { | |
235 | DHerr(DH_F_COMPUTE_KEY,DH_R_INVALID_PUBKEY); | |
236 | goto err; | |
237 | } | |
238 | ||
cb78486d | 239 | if (!dh->meth->bn_mod_exp(dh, tmp, pub_key, dh->priv_key,dh->p,ctx,mont)) |
d02b48c6 | 240 | { |
aa4ce731 | 241 | DHerr(DH_F_COMPUTE_KEY,ERR_R_BN_LIB); |
d02b48c6 RE |
242 | goto err; |
243 | } | |
244 | ||
245 | ret=BN_bn2bin(tmp,key); | |
246 | err: | |
47d55666 NL |
247 | if (ctx != NULL) |
248 | { | |
249 | BN_CTX_end(ctx); | |
250 | BN_CTX_free(ctx); | |
251 | } | |
d02b48c6 RE |
252 | return(ret); |
253 | } | |
13066cee | 254 | |
f971ccb2 RL |
255 | static int dh_bn_mod_exp(const DH *dh, BIGNUM *r, |
256 | const BIGNUM *a, const BIGNUM *p, | |
13066cee DSH |
257 | const BIGNUM *m, BN_CTX *ctx, |
258 | BN_MONT_CTX *m_ctx) | |
6dad7bd6 | 259 | { |
46a64376 BM |
260 | /* If a is only one word long and constant time is false, use the faster |
261 | * exponenentiation function. | |
262 | */ | |
263 | if (a->top == 1 && ((dh->flags & DH_FLAG_NO_EXP_CONSTTIME) != 0)) | |
6dad7bd6 BM |
264 | { |
265 | BN_ULONG A = a->d[0]; | |
266 | return BN_mod_exp_mont_word(r,A,p,m,ctx,m_ctx); | |
267 | } | |
268 | else | |
269 | return BN_mod_exp_mont(r,a,p,m,ctx,m_ctx); | |
270 | } | |
271 | ||
13066cee DSH |
272 | |
273 | static int dh_init(DH *dh) | |
6dad7bd6 | 274 | { |
83c3410b DSH |
275 | #ifdef OPENSSL_FIPS |
276 | FIPS_selftest_check(); | |
277 | #endif | |
13066cee DSH |
278 | dh->flags |= DH_FLAG_CACHE_MONT_P; |
279 | return(1); | |
6dad7bd6 | 280 | } |
13066cee DSH |
281 | |
282 | static int dh_finish(DH *dh) | |
6dad7bd6 | 283 | { |
13066cee | 284 | if(dh->method_mont_p) |
879b1980 | 285 | BN_MONT_CTX_free(dh->method_mont_p); |
13066cee | 286 | return(1); |
6dad7bd6 | 287 | } |