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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 
BN_BLINDING_new(const BIGNUM * A,const BIGNUM * Ai,BIGNUM * mod)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 
BN_BLINDING_free(BN_BLINDING * r)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 
BN_BLINDING_update(BN_BLINDING * b,BN_CTX * ctx)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 
BN_BLINDING_convert(BIGNUM * n,BN_BLINDING * b,BN_CTX * ctx)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 
BN_BLINDING_convert_ex(BIGNUM * n,BIGNUM * r,BN_BLINDING * b,BN_CTX * ctx)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 
BN_BLINDING_invert(BIGNUM * n,BN_BLINDING * b,BN_CTX * ctx)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 
BN_BLINDING_invert_ex(BIGNUM * n,const BIGNUM * r,BN_BLINDING * b,BN_CTX * ctx)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
BN_BLINDING_get_thread_id(const BN_BLINDING * b)280 unsigned long BN_BLINDING_get_thread_id(const BN_BLINDING *b)
281 	{
282 	return b->thread_id;
283 	}
284 
BN_BLINDING_set_thread_id(BN_BLINDING * b,unsigned long n)285 void BN_BLINDING_set_thread_id(BN_BLINDING *b, unsigned long n)
286 	{
287 	b->thread_id = n;
288 	}
289 #endif
290 
BN_BLINDING_thread_id(BN_BLINDING * b)291 CRYPTO_THREADID *BN_BLINDING_thread_id(BN_BLINDING *b)
292 	{
293 	return &b->tid;
294 	}
295 
BN_BLINDING_get_flags(const BN_BLINDING * b)296 unsigned long BN_BLINDING_get_flags(const BN_BLINDING *b)
297 	{
298 	return b->flags;
299 	}
300 
BN_BLINDING_set_flags(BN_BLINDING * b,unsigned long flags)301 void BN_BLINDING_set_flags(BN_BLINDING *b, unsigned long flags)
302 	{
303 	b->flags = flags;
304 	}
305 
BN_BLINDING_create_param(BN_BLINDING * b,const BIGNUM * e,BIGNUM * m,BN_CTX * ctx,int (* bn_mod_exp)(BIGNUM * r,const BIGNUM * a,const BIGNUM * p,const BIGNUM * m,BN_CTX * ctx,BN_MONT_CTX * m_ctx),BN_MONT_CTX * m_ctx)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 }
386