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 	unsigned 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 	ret->counter = BN_BLINDING_COUNTER;
164 	CRYPTO_THREADID_current(&ret->tid);
165 	return(ret);
166 err:
167 	if (ret != NULL) BN_BLINDING_free(ret);
168 	return(NULL);
169 	}
170 
171 void BN_BLINDING_free(BN_BLINDING *r)
172 	{
173 	if(r == NULL)
174 	    return;
175 
176 	if (r->A  != NULL) BN_free(r->A );
177 	if (r->Ai != NULL) BN_free(r->Ai);
178 	if (r->e  != NULL) BN_free(r->e );
179 	if (r->mod != NULL) BN_free(r->mod);
180 	OPENSSL_free(r);
181 	}
182 
183 int BN_BLINDING_update(BN_BLINDING *b, BN_CTX *ctx)
184 	{
185 	int ret=0;
186 
187 	if ((b->A == NULL) || (b->Ai == NULL))
188 		{
189 		BNerr(BN_F_BN_BLINDING_UPDATE,BN_R_NOT_INITIALIZED);
190 		goto err;
191 		}
192 
193 	if (--(b->counter) == 0 && b->e != NULL &&
194 		!(b->flags & BN_BLINDING_NO_RECREATE))
195 		{
196 		/* re-create blinding parameters */
197 		if (!BN_BLINDING_create_param(b, NULL, NULL, ctx, NULL, NULL))
198 			goto err;
199 		}
200 	else if (!(b->flags & BN_BLINDING_NO_UPDATE))
201 		{
202 		if (!BN_mod_mul(b->A,b->A,b->A,b->mod,ctx)) goto err;
203 		if (!BN_mod_mul(b->Ai,b->Ai,b->Ai,b->mod,ctx)) goto err;
204 		}
205 
206 	ret=1;
207 err:
208 	if (b->counter == 0)
209 		b->counter = BN_BLINDING_COUNTER;
210 	return(ret);
211 	}
212 
213 int BN_BLINDING_convert(BIGNUM *n, BN_BLINDING *b, BN_CTX *ctx)
214 	{
215 	return BN_BLINDING_convert_ex(n, NULL, b, ctx);
216 	}
217 
218 int BN_BLINDING_convert_ex(BIGNUM *n, BIGNUM *r, BN_BLINDING *b, BN_CTX *ctx)
219 	{
220 	int ret = 1;
221 
222 	bn_check_top(n);
223 
224 	if ((b->A == NULL) || (b->Ai == NULL))
225 		{
226 		BNerr(BN_F_BN_BLINDING_CONVERT_EX,BN_R_NOT_INITIALIZED);
227 		return(0);
228 		}
229 
230 	if (r != NULL)
231 		{
232 		if (!BN_copy(r, b->Ai)) ret=0;
233 		}
234 
235 	if (!BN_mod_mul(n,n,b->A,b->mod,ctx)) ret=0;
236 
237 	return ret;
238 	}
239 
240 int BN_BLINDING_invert(BIGNUM *n, BN_BLINDING *b, BN_CTX *ctx)
241 	{
242 	return BN_BLINDING_invert_ex(n, NULL, b, ctx);
243 	}
244 
245 int BN_BLINDING_invert_ex(BIGNUM *n, const BIGNUM *r, BN_BLINDING *b, BN_CTX *ctx)
246 	{
247 	int ret;
248 
249 	bn_check_top(n);
250 	if ((b->A == NULL) || (b->Ai == NULL))
251 		{
252 		BNerr(BN_F_BN_BLINDING_INVERT_EX,BN_R_NOT_INITIALIZED);
253 		return(0);
254 		}
255 
256 	if (r != NULL)
257 		ret = BN_mod_mul(n, n, r, b->mod, ctx);
258 	else
259 		ret = BN_mod_mul(n, n, b->Ai, b->mod, ctx);
260 
261 	if (ret >= 0)
262 		{
263 		if (!BN_BLINDING_update(b,ctx))
264 			return(0);
265 		}
266 	bn_check_top(n);
267 	return(ret);
268 	}
269 
270 #ifndef OPENSSL_NO_DEPRECATED
271 unsigned long BN_BLINDING_get_thread_id(const BN_BLINDING *b)
272 	{
273 	return b->thread_id;
274 	}
275 
276 void BN_BLINDING_set_thread_id(BN_BLINDING *b, unsigned long n)
277 	{
278 	b->thread_id = n;
279 	}
280 #endif
281 
282 CRYPTO_THREADID *BN_BLINDING_thread_id(BN_BLINDING *b)
283 	{
284 	return &b->tid;
285 	}
286 
287 unsigned long BN_BLINDING_get_flags(const BN_BLINDING *b)
288 	{
289 	return b->flags;
290 	}
291 
292 void BN_BLINDING_set_flags(BN_BLINDING *b, unsigned long flags)
293 	{
294 	b->flags = flags;
295 	}
296 
297 BN_BLINDING *BN_BLINDING_create_param(BN_BLINDING *b,
298 	const BIGNUM *e, BIGNUM *m, BN_CTX *ctx,
299 	int (*bn_mod_exp)(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
300 			  const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx),
301 	BN_MONT_CTX *m_ctx)
302 {
303 	int    retry_counter = 32;
304 	BN_BLINDING *ret = NULL;
305 
306 	if (b == NULL)
307 		ret = BN_BLINDING_new(NULL, NULL, m);
308 	else
309 		ret = b;
310 
311 	if (ret == NULL)
312 		goto err;
313 
314 	if (ret->A  == NULL && (ret->A  = BN_new()) == NULL)
315 		goto err;
316 	if (ret->Ai == NULL && (ret->Ai	= BN_new()) == NULL)
317 		goto err;
318 
319 	if (e != NULL)
320 		{
321 		if (ret->e != NULL)
322 			BN_free(ret->e);
323 		ret->e = BN_dup(e);
324 		}
325 	if (ret->e == NULL)
326 		goto err;
327 
328 	if (bn_mod_exp != NULL)
329 		ret->bn_mod_exp = bn_mod_exp;
330 	if (m_ctx != NULL)
331 		ret->m_ctx = m_ctx;
332 
333 	do {
334 		if (!BN_rand_range(ret->A, ret->mod)) goto err;
335 		if (BN_mod_inverse(ret->Ai, ret->A, ret->mod, ctx) == NULL)
336 			{
337 			/* this should almost never happen for good RSA keys */
338 			unsigned long error = ERR_peek_last_error();
339 			if (ERR_GET_REASON(error) == BN_R_NO_INVERSE)
340 				{
341 				if (retry_counter-- == 0)
342 				{
343 					BNerr(BN_F_BN_BLINDING_CREATE_PARAM,
344 						BN_R_TOO_MANY_ITERATIONS);
345 					goto err;
346 				}
347 				ERR_clear_error();
348 				}
349 			else
350 				goto err;
351 			}
352 		else
353 			break;
354 	} while (1);
355 
356 	if (ret->bn_mod_exp != NULL && ret->m_ctx != NULL)
357 		{
358 		if (!ret->bn_mod_exp(ret->A, ret->A, ret->e, ret->mod, ctx, ret->m_ctx))
359 			goto err;
360 		}
361 	else
362 		{
363 		if (!BN_mod_exp(ret->A, ret->A, ret->e, ret->mod, ctx))
364 			goto err;
365 		}
366 
367 	return ret;
368 err:
369 	if (b == NULL && ret != NULL)
370 		{
371 		BN_BLINDING_free(ret);
372 		ret = NULL;
373 		}
374 
375 	return ret;
376 }
377