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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 | ||
59 | #include <stdio.h> | |
60 | #include "cryptlib.h" | |
ec577822 BM |
61 | #include <openssl/bn.h> |
62 | #include <openssl/rand.h> | |
63 | #include <openssl/dh.h> | |
d02b48c6 | 64 | |
13066cee | 65 | static int generate_key(DH *dh); |
f971ccb2 RL |
66 | static int compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh); |
67 | static int dh_bn_mod_exp(const DH *dh, BIGNUM *r, | |
68 | const BIGNUM *a, const BIGNUM *p, | |
13066cee DSH |
69 | const BIGNUM *m, BN_CTX *ctx, |
70 | BN_MONT_CTX *m_ctx); | |
71 | static int dh_init(DH *dh); | |
72 | static int dh_finish(DH *dh); | |
73 | ||
6b691a5c | 74 | int DH_generate_key(DH *dh) |
13066cee | 75 | { |
cb78486d | 76 | return dh->meth->generate_key(dh); |
13066cee DSH |
77 | } |
78 | ||
f971ccb2 | 79 | int DH_compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh) |
13066cee | 80 | { |
cb78486d | 81 | return dh->meth->compute_key(key, pub_key, dh); |
13066cee DSH |
82 | } |
83 | ||
84 | static DH_METHOD dh_ossl = { | |
85 | "OpenSSL DH Method", | |
86 | generate_key, | |
87 | compute_key, | |
88 | dh_bn_mod_exp, | |
89 | dh_init, | |
90 | dh_finish, | |
91 | 0, | |
0e4aa0d2 | 92 | NULL, |
13066cee DSH |
93 | NULL |
94 | }; | |
95 | ||
f971ccb2 | 96 | const DH_METHOD *DH_OpenSSL(void) |
13066cee DSH |
97 | { |
98 | return &dh_ossl; | |
99 | } | |
100 | ||
101 | static int generate_key(DH *dh) | |
d02b48c6 RE |
102 | { |
103 | int ok=0; | |
924875e5 | 104 | int generate_new_key=0; |
6aecef81 | 105 | unsigned l; |
c62b26fd | 106 | BN_CTX *ctx; |
dfeab068 | 107 | BN_MONT_CTX *mont; |
d02b48c6 RE |
108 | BIGNUM *pub_key=NULL,*priv_key=NULL; |
109 | ||
c62b26fd BM |
110 | ctx = BN_CTX_new(); |
111 | if (ctx == NULL) goto err; | |
d02b48c6 RE |
112 | |
113 | if (dh->priv_key == NULL) | |
114 | { | |
d02b48c6 RE |
115 | priv_key=BN_new(); |
116 | if (priv_key == NULL) goto err; | |
924875e5 | 117 | generate_new_key=1; |
d02b48c6 RE |
118 | } |
119 | else | |
120 | priv_key=dh->priv_key; | |
121 | ||
122 | if (dh->pub_key == NULL) | |
123 | { | |
124 | pub_key=BN_new(); | |
125 | if (pub_key == NULL) goto err; | |
126 | } | |
127 | else | |
128 | pub_key=dh->pub_key; | |
129 | ||
6ec8e63a DSH |
130 | |
131 | if (dh->flags & DH_FLAG_CACHE_MONT_P) | |
dfeab068 | 132 | { |
879b1980 | 133 | mont = BN_MONT_CTX_set_locked(&dh->method_mont_p, |
6ec8e63a DSH |
134 | CRYPTO_LOCK_DH, dh->p, ctx); |
135 | if (!mont) | |
136 | goto err; | |
dfeab068 | 137 | } |
dfeab068 | 138 | |
924875e5 BM |
139 | if (generate_new_key) |
140 | { | |
de3333ba | 141 | l = dh->length ? dh->length : BN_num_bits(dh->p)-1; /* secret exponent length */ |
924875e5 BM |
142 | if (!BN_rand(priv_key, l, 0, 0)) goto err; |
143 | } | |
cb78486d GT |
144 | if (!dh->meth->bn_mod_exp(dh, pub_key, dh->g, priv_key,dh->p,ctx,mont)) |
145 | goto err; | |
d02b48c6 RE |
146 | |
147 | dh->pub_key=pub_key; | |
148 | dh->priv_key=priv_key; | |
149 | ok=1; | |
150 | err: | |
151 | if (ok != 1) | |
aa4ce731 | 152 | DHerr(DH_F_GENERATE_KEY,ERR_R_BN_LIB); |
d02b48c6 RE |
153 | |
154 | if ((pub_key != NULL) && (dh->pub_key == NULL)) BN_free(pub_key); | |
155 | if ((priv_key != NULL) && (dh->priv_key == NULL)) BN_free(priv_key); | |
c62b26fd | 156 | BN_CTX_free(ctx); |
d02b48c6 RE |
157 | return(ok); |
158 | } | |
159 | ||
f971ccb2 | 160 | static int compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh) |
d02b48c6 | 161 | { |
c62b26fd | 162 | BN_CTX *ctx; |
dfeab068 | 163 | BN_MONT_CTX *mont; |
d02b48c6 RE |
164 | BIGNUM *tmp; |
165 | int ret= -1; | |
166 | ||
c62b26fd BM |
167 | ctx = BN_CTX_new(); |
168 | if (ctx == NULL) goto err; | |
169 | BN_CTX_start(ctx); | |
170 | tmp = BN_CTX_get(ctx); | |
d02b48c6 RE |
171 | |
172 | if (dh->priv_key == NULL) | |
173 | { | |
aa4ce731 | 174 | DHerr(DH_F_COMPUTE_KEY,DH_R_NO_PRIVATE_VALUE); |
d02b48c6 RE |
175 | goto err; |
176 | } | |
6ec8e63a DSH |
177 | |
178 | if (dh->flags & DH_FLAG_CACHE_MONT_P) | |
dfeab068 | 179 | { |
879b1980 | 180 | mont = BN_MONT_CTX_set_locked(&dh->method_mont_p, |
6ec8e63a DSH |
181 | CRYPTO_LOCK_DH, dh->p, ctx); |
182 | if (!mont) | |
183 | goto err; | |
dfeab068 RE |
184 | } |
185 | ||
cb78486d | 186 | if (!dh->meth->bn_mod_exp(dh, tmp, pub_key, dh->priv_key,dh->p,ctx,mont)) |
d02b48c6 | 187 | { |
aa4ce731 | 188 | DHerr(DH_F_COMPUTE_KEY,ERR_R_BN_LIB); |
d02b48c6 RE |
189 | goto err; |
190 | } | |
191 | ||
192 | ret=BN_bn2bin(tmp,key); | |
193 | err: | |
c62b26fd BM |
194 | BN_CTX_end(ctx); |
195 | BN_CTX_free(ctx); | |
d02b48c6 RE |
196 | return(ret); |
197 | } | |
13066cee | 198 | |
f971ccb2 RL |
199 | static int dh_bn_mod_exp(const DH *dh, BIGNUM *r, |
200 | const BIGNUM *a, const BIGNUM *p, | |
13066cee DSH |
201 | const BIGNUM *m, BN_CTX *ctx, |
202 | BN_MONT_CTX *m_ctx) | |
6dad7bd6 BM |
203 | { |
204 | if (a->top == 1) | |
205 | { | |
206 | BN_ULONG A = a->d[0]; | |
207 | return BN_mod_exp_mont_word(r,A,p,m,ctx,m_ctx); | |
208 | } | |
209 | else | |
210 | return BN_mod_exp_mont(r,a,p,m,ctx,m_ctx); | |
211 | } | |
212 | ||
13066cee DSH |
213 | |
214 | static int dh_init(DH *dh) | |
6dad7bd6 | 215 | { |
13066cee DSH |
216 | dh->flags |= DH_FLAG_CACHE_MONT_P; |
217 | return(1); | |
6dad7bd6 | 218 | } |
13066cee DSH |
219 | |
220 | static int dh_finish(DH *dh) | |
6dad7bd6 | 221 | { |
13066cee | 222 | if(dh->method_mont_p) |
879b1980 | 223 | BN_MONT_CTX_free(dh->method_mont_p); |
13066cee | 224 | return(1); |
6dad7bd6 | 225 | } |