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1 /* crypto/dsa/dsa_gen.c */ | |
2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) | |
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 #undef GENUINE_DSA | |
60 | |
61 #ifdef GENUINE_DSA | |
62 /* Parameter generation follows the original release of FIPS PUB 186, | |
63 * Appendix 2.2 (i.e. use SHA as defined in FIPS PUB 180) */ | |
64 #define HASH EVP_sha() | |
65 #else | |
66 /* Parameter generation follows the updated Appendix 2.2 for FIPS PUB 186, | |
67 * also Appendix 2.2 of FIPS PUB 186-1 (i.e. use SHA as defined in | |
68 * FIPS PUB 180-1) */ | |
69 #define HASH EVP_sha1() | |
70 #endif | |
71 | |
72 #include <openssl/opensslconf.h> /* To see if OPENSSL_NO_SHA is defined */ | |
73 | |
74 #ifndef OPENSSL_NO_SHA | |
75 | |
76 #include <stdio.h> | |
77 #include "cryptlib.h" | |
78 #include <openssl/evp.h> | |
79 #include <openssl/bn.h> | |
80 #include <openssl/rand.h> | |
81 #include <openssl/sha.h> | |
82 #include "dsa_locl.h" | |
83 | |
84 #ifdef OPENSSL_FIPS | |
85 #include <openssl/fips.h> | |
86 #endif | |
87 | |
88 int DSA_generate_parameters_ex(DSA *ret, int bits, | |
89 const unsigned char *seed_in, int seed_len, | |
90 int *counter_ret, unsigned long *h_ret, BN_GENCB *cb) | |
91 { | |
92 #ifdef OPENSSL_FIPS | |
93 if (FIPS_mode() && !(ret->meth->flags & DSA_FLAG_FIPS_METHOD) | |
94 && !(ret->flags & DSA_FLAG_NON_FIPS_ALLOW)) | |
95 { | |
96 DSAerr(DSA_F_DSA_GENERATE_PARAMETERS_EX, DSA_R_NON_FIPS_DSA_METH
OD); | |
97 return 0; | |
98 } | |
99 #endif | |
100 if(ret->meth->dsa_paramgen) | |
101 return ret->meth->dsa_paramgen(ret, bits, seed_in, seed_len, | |
102 counter_ret, h_ret, cb); | |
103 #ifdef OPENSSL_FIPS | |
104 else if (FIPS_mode()) | |
105 { | |
106 return FIPS_dsa_generate_parameters_ex(ret, bits, | |
107 seed_in, seed_len, | |
108 counter_ret, h_ret, cb); | |
109 } | |
110 #endif | |
111 else | |
112 { | |
113 const EVP_MD *evpmd; | |
114 size_t qbits = bits >= 2048 ? 256 : 160; | |
115 | |
116 if (bits >= 2048) | |
117 { | |
118 qbits = 256; | |
119 evpmd = EVP_sha256(); | |
120 } | |
121 else | |
122 { | |
123 qbits = 160; | |
124 evpmd = EVP_sha1(); | |
125 } | |
126 | |
127 return dsa_builtin_paramgen(ret, bits, qbits, evpmd, | |
128 seed_in, seed_len, NULL, counter_ret, h_ret, cb); | |
129 } | |
130 } | |
131 | |
132 int dsa_builtin_paramgen(DSA *ret, size_t bits, size_t qbits, | |
133 const EVP_MD *evpmd, const unsigned char *seed_in, size_t seed_len, | |
134 unsigned char *seed_out, | |
135 int *counter_ret, unsigned long *h_ret, BN_GENCB *cb) | |
136 { | |
137 int ok=0; | |
138 unsigned char seed[SHA256_DIGEST_LENGTH]; | |
139 unsigned char md[SHA256_DIGEST_LENGTH]; | |
140 unsigned char buf[SHA256_DIGEST_LENGTH],buf2[SHA256_DIGEST_LENGTH]; | |
141 BIGNUM *r0,*W,*X,*c,*test; | |
142 BIGNUM *g=NULL,*q=NULL,*p=NULL; | |
143 BN_MONT_CTX *mont=NULL; | |
144 int i, k, n=0, m=0, qsize = qbits >> 3; | |
145 int counter=0; | |
146 int r=0; | |
147 BN_CTX *ctx=NULL; | |
148 unsigned int h=2; | |
149 | |
150 if (qsize != SHA_DIGEST_LENGTH && qsize != SHA224_DIGEST_LENGTH && | |
151 qsize != SHA256_DIGEST_LENGTH) | |
152 /* invalid q size */ | |
153 return 0; | |
154 | |
155 if (evpmd == NULL) | |
156 /* use SHA1 as default */ | |
157 evpmd = EVP_sha1(); | |
158 | |
159 if (bits < 512) | |
160 bits = 512; | |
161 | |
162 bits = (bits+63)/64*64; | |
163 | |
164 /* NB: seed_len == 0 is special case: copy generated seed to | |
165 * seed_in if it is not NULL. | |
166 */ | |
167 if (seed_len && (seed_len < (size_t)qsize)) | |
168 seed_in = NULL; /* seed buffer too small -- ignore */ | |
169 if (seed_len > (size_t)qsize) | |
170 seed_len = qsize; /* App. 2.2 of FIPS PUB 186 allows large
r SEED, | |
171 * but our internal buffers are restrict
ed to 160 bits*/ | |
172 if (seed_in != NULL) | |
173 memcpy(seed, seed_in, seed_len); | |
174 | |
175 if ((ctx=BN_CTX_new()) == NULL) | |
176 goto err; | |
177 | |
178 if ((mont=BN_MONT_CTX_new()) == NULL) | |
179 goto err; | |
180 | |
181 BN_CTX_start(ctx); | |
182 r0 = BN_CTX_get(ctx); | |
183 g = BN_CTX_get(ctx); | |
184 W = BN_CTX_get(ctx); | |
185 q = BN_CTX_get(ctx); | |
186 X = BN_CTX_get(ctx); | |
187 c = BN_CTX_get(ctx); | |
188 p = BN_CTX_get(ctx); | |
189 test = BN_CTX_get(ctx); | |
190 | |
191 if (!BN_lshift(test,BN_value_one(),bits-1)) | |
192 goto err; | |
193 | |
194 for (;;) | |
195 { | |
196 for (;;) /* find q */ | |
197 { | |
198 int seed_is_random; | |
199 | |
200 /* step 1 */ | |
201 if(!BN_GENCB_call(cb, 0, m++)) | |
202 goto err; | |
203 | |
204 if (!seed_len) | |
205 { | |
206 RAND_pseudo_bytes(seed, qsize); | |
207 seed_is_random = 1; | |
208 } | |
209 else | |
210 { | |
211 seed_is_random = 0; | |
212 seed_len=0; /* use random seed if 'seed_in' turn
s out to be bad*/ | |
213 } | |
214 memcpy(buf , seed, qsize); | |
215 memcpy(buf2, seed, qsize); | |
216 /* precompute "SEED + 1" for step 7: */ | |
217 for (i = qsize-1; i >= 0; i--) | |
218 { | |
219 buf[i]++; | |
220 if (buf[i] != 0) | |
221 break; | |
222 } | |
223 | |
224 /* step 2 */ | |
225 if (!EVP_Digest(seed, qsize, md, NULL, evpmd, NULL)) | |
226 goto err; | |
227 if (!EVP_Digest(buf, qsize, buf2, NULL, evpmd, NULL)) | |
228 goto err; | |
229 for (i = 0; i < qsize; i++) | |
230 md[i]^=buf2[i]; | |
231 | |
232 /* step 3 */ | |
233 md[0] |= 0x80; | |
234 md[qsize-1] |= 0x01; | |
235 if (!BN_bin2bn(md, qsize, q)) | |
236 goto err; | |
237 | |
238 /* step 4 */ | |
239 r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx, | |
240 seed_is_random, cb); | |
241 if (r > 0) | |
242 break; | |
243 if (r != 0) | |
244 goto err; | |
245 | |
246 /* do a callback call */ | |
247 /* step 5 */ | |
248 } | |
249 | |
250 if(!BN_GENCB_call(cb, 2, 0)) goto err; | |
251 if(!BN_GENCB_call(cb, 3, 0)) goto err; | |
252 | |
253 /* step 6 */ | |
254 counter=0; | |
255 /* "offset = 2" */ | |
256 | |
257 n=(bits-1)/160; | |
258 | |
259 for (;;) | |
260 { | |
261 if ((counter != 0) && !BN_GENCB_call(cb, 0, counter)) | |
262 goto err; | |
263 | |
264 /* step 7 */ | |
265 BN_zero(W); | |
266 /* now 'buf' contains "SEED + offset - 1" */ | |
267 for (k=0; k<=n; k++) | |
268 { | |
269 /* obtain "SEED + offset + k" by incrementing: *
/ | |
270 for (i = qsize-1; i >= 0; i--) | |
271 { | |
272 buf[i]++; | |
273 if (buf[i] != 0) | |
274 break; | |
275 } | |
276 | |
277 if (!EVP_Digest(buf, qsize, md ,NULL, evpmd, | |
278 NULL)) | |
279 goto err; | |
280 | |
281 /* step 8 */ | |
282 if (!BN_bin2bn(md, qsize, r0)) | |
283 goto err; | |
284 if (!BN_lshift(r0,r0,(qsize << 3)*k)) goto err; | |
285 if (!BN_add(W,W,r0)) goto err; | |
286 } | |
287 | |
288 /* more of step 8 */ | |
289 if (!BN_mask_bits(W,bits-1)) goto err; | |
290 if (!BN_copy(X,W)) goto err; | |
291 if (!BN_add(X,X,test)) goto err; | |
292 | |
293 /* step 9 */ | |
294 if (!BN_lshift1(r0,q)) goto err; | |
295 if (!BN_mod(c,X,r0,ctx)) goto err; | |
296 if (!BN_sub(r0,c,BN_value_one())) goto err; | |
297 if (!BN_sub(p,X,r0)) goto err; | |
298 | |
299 /* step 10 */ | |
300 if (BN_cmp(p,test) >= 0) | |
301 { | |
302 /* step 11 */ | |
303 r = BN_is_prime_fasttest_ex(p, DSS_prime_checks, | |
304 ctx, 1, cb); | |
305 if (r > 0) | |
306 goto end; /* found it */ | |
307 if (r != 0) | |
308 goto err; | |
309 } | |
310 | |
311 /* step 13 */ | |
312 counter++; | |
313 /* "offset = offset + n + 1" */ | |
314 | |
315 /* step 14 */ | |
316 if (counter >= 4096) break; | |
317 } | |
318 } | |
319 end: | |
320 if(!BN_GENCB_call(cb, 2, 1)) | |
321 goto err; | |
322 | |
323 /* We now need to generate g */ | |
324 /* Set r0=(p-1)/q */ | |
325 if (!BN_sub(test,p,BN_value_one())) goto err; | |
326 if (!BN_div(r0,NULL,test,q,ctx)) goto err; | |
327 | |
328 if (!BN_set_word(test,h)) goto err; | |
329 if (!BN_MONT_CTX_set(mont,p,ctx)) goto err; | |
330 | |
331 for (;;) | |
332 { | |
333 /* g=test^r0%p */ | |
334 if (!BN_mod_exp_mont(g,test,r0,p,ctx,mont)) goto err; | |
335 if (!BN_is_one(g)) break; | |
336 if (!BN_add(test,test,BN_value_one())) goto err; | |
337 h++; | |
338 } | |
339 | |
340 if(!BN_GENCB_call(cb, 3, 1)) | |
341 goto err; | |
342 | |
343 ok=1; | |
344 err: | |
345 if (ok) | |
346 { | |
347 if(ret->p) BN_free(ret->p); | |
348 if(ret->q) BN_free(ret->q); | |
349 if(ret->g) BN_free(ret->g); | |
350 ret->p=BN_dup(p); | |
351 ret->q=BN_dup(q); | |
352 ret->g=BN_dup(g); | |
353 if (ret->p == NULL || ret->q == NULL || ret->g == NULL) | |
354 { | |
355 ok=0; | |
356 goto err; | |
357 } | |
358 if (counter_ret != NULL) *counter_ret=counter; | |
359 if (h_ret != NULL) *h_ret=h; | |
360 if (seed_out) | |
361 memcpy(seed_out, seed, qsize); | |
362 } | |
363 if(ctx) | |
364 { | |
365 BN_CTX_end(ctx); | |
366 BN_CTX_free(ctx); | |
367 } | |
368 if (mont != NULL) BN_MONT_CTX_free(mont); | |
369 return ok; | |
370 } | |
371 #endif | |
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