1 /* crypto/bn/bn_blind.c */
2 /* ====================================================================
3 * Copyright (c) 1998-2006 The OpenSSL Project. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 *
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in
14 * the documentation and/or other materials provided with the
15 * distribution.
16 *
17 * 3. All advertising materials mentioning features or use of this
18 * software must display the following acknowledgment:
19 * "This product includes software developed by the OpenSSL Project
20 * for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
21 *
22 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
23 * endorse or promote products derived from this software without
24 * prior written permission. For written permission, please contact
25 * openssl-core@openssl.org.
26 *
27 * 5. Products derived from this software may not be called "OpenSSL"
28 * nor may "OpenSSL" appear in their names without prior written
29 * permission of the OpenSSL Project.
30 *
31 * 6. Redistributions of any form whatsoever must retain the following
32 * acknowledgment:
33 * "This product includes software developed by the OpenSSL Project
34 * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
35 *
36 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
37 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
38 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
39 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
40 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
41 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
42 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
43 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
44 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
45 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
46 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
47 * OF THE POSSIBILITY OF SUCH DAMAGE.
48 * ====================================================================
49 *
50 * This product includes cryptographic software written by Eric Young
51 * (eay@cryptsoft.com). This product includes software written by Tim
52 * Hudson (tjh@cryptsoft.com).
53 *
54 */
55 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
56 * All rights reserved.
57 *
58 * This package is an SSL implementation written
59 * by Eric Young (eay@cryptsoft.com).
60 * The implementation was written so as to conform with Netscapes SSL.
61 *
62 * This library is free for commercial and non-commercial use as long as
63 * the following conditions are aheared to. The following conditions
64 * apply to all code found in this distribution, be it the RC4, RSA,
65 * lhash, DES, etc., code; not just the SSL code. The SSL documentation
66 * included with this distribution is covered by the same copyright terms
67 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
68 *
69 * Copyright remains Eric Young's, and as such any Copyright notices in
70 * the code are not to be removed.
71 * If this package is used in a product, Eric Young should be given attribution
72 * as the author of the parts of the library used.
73 * This can be in the form of a textual message at program startup or
74 * in documentation (online or textual) provided with the package.
75 *
76 * Redistribution and use in source and binary forms, with or without
77 * modification, are permitted provided that the following conditions
78 * are met:
79 * 1. Redistributions of source code must retain the copyright
80 * notice, this list of conditions and the following disclaimer.
81 * 2. Redistributions in binary form must reproduce the above copyright
82 * notice, this list of conditions and the following disclaimer in the
83 * documentation and/or other materials provided with the distribution.
84 * 3. All advertising materials mentioning features or use of this software
85 * must display the following acknowledgement:
86 * "This product includes cryptographic software written by
87 * Eric Young (eay@cryptsoft.com)"
88 * The word 'cryptographic' can be left out if the rouines from the library
89 * being used are not cryptographic related :-).
90 * 4. If you include any Windows specific code (or a derivative thereof) from
91 * the apps directory (application code) you must include an acknowledgement:
92 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
93 *
94 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
95 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
96 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
97 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
98 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
99 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
100 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
101 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
102 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
103 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
104 * SUCH DAMAGE.
105 *
106 * The licence and distribution terms for any publically available version or
107 * derivative of this code cannot be changed. i.e. this code cannot simply be
108 * copied and put under another distribution licence
109 * [including the GNU Public Licence.]
110 */
111
112 #include <stdio.h>
113 #include "cryptlib.h"
114 #include "bn_lcl.h"
115
116 #define BN_BLINDING_COUNTER 32
117
118 struct bn_blinding_st
119 {
120 BIGNUM *A;
121 BIGNUM *Ai;
122 BIGNUM *e;
123 BIGNUM *mod; /* just a reference */
124 #ifndef OPENSSL_NO_DEPRECATED
125 unsigned long thread_id; /* added in OpenSSL 0.9.6j and 0.9.7b;
126 * used only by crypto/rsa/rsa_eay.c, rsa_lib.c */
127 #endif
128 CRYPTO_THREADID tid;
129 int counter;
130 unsigned long flags;
131 BN_MONT_CTX *m_ctx;
132 int (*bn_mod_exp)(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
133 const BIGNUM *m, BN_CTX *ctx,
134 BN_MONT_CTX *m_ctx);
135 };
136
137 BN_BLINDING *BN_BLINDING_new(const BIGNUM *A, const BIGNUM *Ai, BIGNUM *mod)
138 {
139 BN_BLINDING *ret=NULL;
140
141 bn_check_top(mod);
142
143 if ((ret=(BN_BLINDING *)OPENSSL_malloc(sizeof(BN_BLINDING))) == NULL)
144 {
145 BNerr(BN_F_BN_BLINDING_NEW,ERR_R_MALLOC_FAILURE);
146 return(NULL);
147 }
148 memset(ret,0,sizeof(BN_BLINDING));
149 if (A != NULL)
150 {
151 if ((ret->A = BN_dup(A)) == NULL) goto err;
152 }
153 if (Ai != NULL)
154 {
155 if ((ret->Ai = BN_dup(Ai)) == NULL) goto err;
156 }
157
158 /* save a copy of mod in the BN_BLINDING structure */
159 if ((ret->mod = BN_dup(mod)) == NULL) goto err;
160 if (BN_get_flags(mod, BN_FLG_CONSTTIME) != 0)
161 BN_set_flags(ret->mod, BN_FLG_CONSTTIME);
162
163 /* Set the counter to the special value -1
164 * to indicate that this is never-used fresh blinding
165 * that does not need updating before first use. */
166 ret->counter = -1;
167 CRYPTO_THREADID_current(&ret->tid);
168 return(ret);
169 err:
170 if (ret != NULL) BN_BLINDING_free(ret);
171 return(NULL);
172 }
173
174 void BN_BLINDING_free(BN_BLINDING *r)
175 {
176 if(r == NULL)
177 return;
178
179 if (r->A != NULL) BN_free(r->A );
180 if (r->Ai != NULL) BN_free(r->Ai);
181 if (r->e != NULL) BN_free(r->e );
182 if (r->mod != NULL) BN_free(r->mod);
183 OPENSSL_free(r);
184 }
185
186 int BN_BLINDING_update(BN_BLINDING *b, BN_CTX *ctx)
187 {
188 int ret=0;
189
190 if ((b->A == NULL) || (b->Ai == NULL))
191 {
192 BNerr(BN_F_BN_BLINDING_UPDATE,BN_R_NOT_INITIALIZED);
193 goto err;
194 }
195
196 if (b->counter == -1)
197 b->counter = 0;
198
199 if (++b->counter == BN_BLINDING_COUNTER && b->e != NULL &&
200 !(b->flags & BN_BLINDING_NO_RECREATE))
201 {
202 /* re-create blinding parameters */
203 if (!BN_BLINDING_create_param(b, NULL, NULL, ctx, NULL, NULL))
204 goto err;
205 }
206 else if (!(b->flags & BN_BLINDING_NO_UPDATE))
207 {
208 if (!BN_mod_mul(b->A,b->A,b->A,b->mod,ctx)) goto err;
209 if (!BN_mod_mul(b->Ai,b->Ai,b->Ai,b->mod,ctx)) goto err;
210 }
211
212 ret=1;
213 err:
214 if (b->counter == BN_BLINDING_COUNTER)
215 b->counter = 0;
216 return(ret);
217 }
218
219 int BN_BLINDING_convert(BIGNUM *n, BN_BLINDING *b, BN_CTX *ctx)
220 {
221 return BN_BLINDING_convert_ex(n, NULL, b, ctx);
222 }
223
224 int BN_BLINDING_convert_ex(BIGNUM *n, BIGNUM *r, BN_BLINDING *b, BN_CTX *ctx)
225 {
226 int ret = 1;
227
228 bn_check_top(n);
229
230 if ((b->A == NULL) || (b->Ai == NULL))
231 {
232 BNerr(BN_F_BN_BLINDING_CONVERT_EX,BN_R_NOT_INITIALIZED);
233 return(0);
234 }
235
236 if (b->counter == -1)
237 /* Fresh blinding, doesn't need updating. */
238 b->counter = 0;
239 else if (!BN_BLINDING_update(b,ctx))
240 return(0);
241
242 if (r != NULL)
243 {
244 if (!BN_copy(r, b->Ai)) ret=0;
245 }
246
247 if (!BN_mod_mul(n,n,b->A,b->mod,ctx)) ret=0;
248
249 return ret;
250 }
251
252 int BN_BLINDING_invert(BIGNUM *n, BN_BLINDING *b, BN_CTX *ctx)
253 {
254 return BN_BLINDING_invert_ex(n, NULL, b, ctx);
255 }
256
257 int BN_BLINDING_invert_ex(BIGNUM *n, const BIGNUM *r, BN_BLINDING *b, BN_CTX *ctx)
258 {
259 int ret;
260
261 bn_check_top(n);
262
263 if (r != NULL)
264 ret = BN_mod_mul(n, n, r, b->mod, ctx);
265 else
266 {
267 if (b->Ai == NULL)
268 {
269 BNerr(BN_F_BN_BLINDING_INVERT_EX,BN_R_NOT_INITIALIZED);
270 return(0);
271 }
272 ret = BN_mod_mul(n, n, b->Ai, b->mod, ctx);
273 }
274
275 bn_check_top(n);
276 return(ret);
277 }
278
279 #ifndef OPENSSL_NO_DEPRECATED
280 unsigned long BN_BLINDING_get_thread_id(const BN_BLINDING *b)
281 {
282 return b->thread_id;
283 }
284
285 void BN_BLINDING_set_thread_id(BN_BLINDING *b, unsigned long n)
286 {
287 b->thread_id = n;
288 }
289 #endif
290
291 CRYPTO_THREADID *BN_BLINDING_thread_id(BN_BLINDING *b)
292 {
293 return &b->tid;
294 }
295
296 unsigned long BN_BLINDING_get_flags(const BN_BLINDING *b)
297 {
298 return b->flags;
299 }
300
301 void BN_BLINDING_set_flags(BN_BLINDING *b, unsigned long flags)
302 {
303 b->flags = flags;
304 }
305
306 BN_BLINDING *BN_BLINDING_create_param(BN_BLINDING *b,
307 const BIGNUM *e, BIGNUM *m, BN_CTX *ctx,
308 int (*bn_mod_exp)(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
309 const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx),
310 BN_MONT_CTX *m_ctx)
311 {
312 int retry_counter = 32;
313 BN_BLINDING *ret = NULL;
314
315 if (b == NULL)
316 ret = BN_BLINDING_new(NULL, NULL, m);
317 else
318 ret = b;
319
320 if (ret == NULL)
321 goto err;
322
323 if (ret->A == NULL && (ret->A = BN_new()) == NULL)
324 goto err;
325 if (ret->Ai == NULL && (ret->Ai = BN_new()) == NULL)
326 goto err;
327
328 if (e != NULL)
329 {
330 if (ret->e != NULL)
331 BN_free(ret->e);
332 ret->e = BN_dup(e);
333 }
334 if (ret->e == NULL)
335 goto err;
336
337 if (bn_mod_exp != NULL)
338 ret->bn_mod_exp = bn_mod_exp;
339 if (m_ctx != NULL)
340 ret->m_ctx = m_ctx;
341
342 do {
343 if (!BN_rand_range(ret->A, ret->mod)) goto err;
344 if (BN_mod_inverse(ret->Ai, ret->A, ret->mod, ctx) == NULL)
345 {
346 /* this should almost never happen for good RSA keys */
347 unsigned long error = ERR_peek_last_error();
348 if (ERR_GET_REASON(error) == BN_R_NO_INVERSE)
349 {
350 if (retry_counter-- == 0)
351 {
352 BNerr(BN_F_BN_BLINDING_CREATE_PARAM,
353 BN_R_TOO_MANY_ITERATIONS);
354 goto err;
355 }
356 ERR_clear_error();
357 }
358 else
359 goto err;
360 }
361 else
362 break;
363 } while (1);
364
365 if (ret->bn_mod_exp != NULL && ret->m_ctx != NULL)
366 {
367 if (!ret->bn_mod_exp(ret->A, ret->A, ret->e, ret->mod, ctx, ret->m_ctx))
368 goto err;
369 }
370 else
371 {
372 if (!BN_mod_exp(ret->A, ret->A, ret->e, ret->mod, ctx))
373 goto err;
374 }
375
376 return ret;
377 err:
378 if (b == NULL && ret != NULL)
379 {
380 BN_BLINDING_free(ret);
381 ret = NULL;
382 }
383
384 return ret;
385 }