Head

GCC Code Coverage Report

Directory:	./		Exec	Total	Coverage
File:	lib/libcrypto/crypto/../../libssl/src/crypto/bn/bn_exp2.c	Lines:	81	115	70.4 %
Date:	2016-12-06	Branches:	67	114	58.8 %


/* $OpenBSD: bn_exp2.c,v 1.10 2015/02/09 15:49:22 jsing Exp $ */
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 *
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 *
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 *
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */
/* ====================================================================
 * Copyright (c) 1998-2000 The OpenSSL Project.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
 *
 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    openssl-core@openssl.org.
 *
 * 5. Products derived from this software may not be called "OpenSSL"
 *    nor may "OpenSSL" appear in their names without prior written
 *    permission of the OpenSSL Project.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
 *
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 * ====================================================================
 *
 * This product includes cryptographic software written by Eric Young
 * (eay@cryptsoft.com).  This product includes software written by Tim
 * Hudson (tjh@cryptsoft.com).
 *
 */

#include <stdio.h>

#include <openssl/err.h>

#include "bn_lcl.h"

#define TABLE_SIZE	32

int
BN_mod_exp2_mont(BIGNUM *rr, const BIGNUM *a1, const BIGNUM *p1,
    const BIGNUM *a2, const BIGNUM *p2, const BIGNUM *m, BN_CTX *ctx,
    BN_MONT_CTX *in_mont)
{
	int i, j, bits, b, bits1, bits2, ret = 0, wpos1, wpos2, window1, window2, wvalue1, wvalue2;
	int r_is_one = 1;
	BIGNUM *d, *r;
	const BIGNUM *a_mod_m;
	/* Tables of variables obtained from 'ctx' */
	BIGNUM *val1[TABLE_SIZE], *val2[TABLE_SIZE];
	BN_MONT_CTX *mont = NULL;

	bn_check_top(a1);
	bn_check_top(p1);
	bn_check_top(a2);
	bn_check_top(p2);
	bn_check_top(m);

	if (!(m->d[0] & 1)) {
		BNerr(BN_F_BN_MOD_EXP2_MONT, BN_R_CALLED_WITH_EVEN_MODULUS);
		return (0);
	}
	bits1 = BN_num_bits(p1);
	bits2 = BN_num_bits(p2);
	if ((bits1 == 0) && (bits2 == 0)) {
		ret = BN_one(rr);
		return ret;
	}

	bits = (bits1 > bits2) ? bits1 : bits2;

	BN_CTX_start(ctx);
	if ((d = BN_CTX_get(ctx)) == NULL)
		goto err;
	if ((r = BN_CTX_get(ctx)) == NULL)
		goto err;
	if ((val1[0] = BN_CTX_get(ctx)) == NULL)
		goto err;
	if ((val2[0] = BN_CTX_get(ctx)) == NULL)
		goto err;

	if (in_mont != NULL)
		mont = in_mont;
	else {
		if ((mont = BN_MONT_CTX_new()) == NULL)
			goto err;
		if (!BN_MONT_CTX_set(mont, m, ctx))
			goto err;
	}

	window1 = BN_window_bits_for_exponent_size(bits1);
	window2 = BN_window_bits_for_exponent_size(bits2);

	/*
	 * Build table for a1:   val1[i] := a1^(2*i + 1) mod m  for i = 0 .. 2^(window1-1)
	 */
	if (a1->neg || BN_ucmp(a1, m) >= 0) {
		if (!BN_mod(val1[0], a1, m, ctx))
			goto err;
		a_mod_m = val1[0];
	} else
		a_mod_m = a1;
	if (BN_is_zero(a_mod_m)) {
		BN_zero(rr);
		ret = 1;
		goto err;
	}

	if (!BN_to_montgomery(val1[0], a_mod_m, mont, ctx))
		goto err;
	if (window1 > 1) {
		if (!BN_mod_mul_montgomery(d, val1[0], val1[0], mont, ctx))
			goto err;

		j = 1 << (window1 - 1);
		for (i = 1; i < j; i++) {
			if (((val1[i] = BN_CTX_get(ctx)) == NULL) ||
			    !BN_mod_mul_montgomery(val1[i], val1[i - 1],
			    d, mont, ctx))
				goto err;
		}
	}


	/*
	 * Build table for a2:   val2[i] := a2^(2*i + 1) mod m  for i = 0 .. 2^(window2-1)
	 */
	if (a2->neg || BN_ucmp(a2, m) >= 0) {
		if (!BN_mod(val2[0], a2, m, ctx))
			goto err;
		a_mod_m = val2[0];
	} else
		a_mod_m = a2;
	if (BN_is_zero(a_mod_m)) {
		BN_zero(rr);
		ret = 1;
		goto err;
	}
	if (!BN_to_montgomery(val2[0], a_mod_m, mont, ctx))
		goto err;
	if (window2 > 1) {
		if (!BN_mod_mul_montgomery(d, val2[0], val2[0], mont, ctx))
			goto err;

		j = 1 << (window2 - 1);
		for (i = 1; i < j; i++) {
			if (((val2[i] = BN_CTX_get(ctx)) == NULL) ||
			    !BN_mod_mul_montgomery(val2[i], val2[i - 1],
			    d, mont, ctx))
				goto err;
		}
	}


	/* Now compute the power product, using independent windows. */
	r_is_one = 1;
	wvalue1 = 0;  /* The 'value' of the first window */
	wvalue2 = 0;  /* The 'value' of the second window */
	wpos1 = 0;    /* If wvalue1 > 0, the bottom bit of the first window */
	wpos2 = 0;    /* If wvalue2 > 0, the bottom bit of the second window */

	if (!BN_to_montgomery(r, BN_value_one(), mont, ctx))
		goto err;
	for (b = bits - 1; b >= 0; b--) {
		if (!r_is_one) {
			if (!BN_mod_mul_montgomery(r, r,r, mont, ctx))
				goto err;
		}

		if (!wvalue1)
			if (BN_is_bit_set(p1, b)) {
			/* consider bits b-window1+1 .. b for this window */
			i = b - window1 + 1;
			while (!BN_is_bit_set(p1, i)) /* works for i<0 */
				i++;
			wpos1 = i;
			wvalue1 = 1;
			for (i = b - 1; i >= wpos1; i--) {
				wvalue1 <<= 1;
				if (BN_is_bit_set(p1, i))
					wvalue1++;
			}
		}

		if (!wvalue2)
			if (BN_is_bit_set(p2, b)) {
			/* consider bits b-window2+1 .. b for this window */
			i = b - window2 + 1;
			while (!BN_is_bit_set(p2, i))
				i++;
			wpos2 = i;
			wvalue2 = 1;
			for (i = b - 1; i >= wpos2; i--) {
				wvalue2 <<= 1;
				if (BN_is_bit_set(p2, i))
					wvalue2++;
			}
		}

		if (wvalue1 && b == wpos1) {
			/* wvalue1 is odd and < 2^window1 */
			if (!BN_mod_mul_montgomery(r, r, val1[wvalue1 >> 1],
			    mont, ctx))
				goto err;
			wvalue1 = 0;
			r_is_one = 0;
		}

		if (wvalue2 && b == wpos2) {
			/* wvalue2 is odd and < 2^window2 */
			if (!BN_mod_mul_montgomery(r, r, val2[wvalue2 >> 1],
			    mont, ctx))
				goto err;
			wvalue2 = 0;
			r_is_one = 0;
		}
	}
	if (!BN_from_montgomery(rr, r,mont, ctx))
		goto err;
	ret = 1;

err:
	if ((in_mont == NULL) && (mont != NULL))
		BN_MONT_CTX_free(mont);
	BN_CTX_end(ctx);
	bn_check_top(rr);
	return (ret);
}


Generated by: GCOVR (Version 3.3)

Line	Branch	Exec	Source
1			/* $OpenBSD: bn_exp2.c,v 1.10 2015/02/09 15:49:22 jsing Exp $ */
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			* Copyright (c) 1998-2000 The OpenSSL Project. All rights reserved.
60			*
61			* Redistribution and use in source and binary forms, with or without
62			* modification, are permitted provided that the following conditions
63			* are met:
64			*
65			* 1. Redistributions of source code must retain the above copyright
66			* notice, this list of conditions and the following disclaimer.
67			*
68			* 2. Redistributions in binary form must reproduce the above copyright
69			* notice, this list of conditions and the following disclaimer in
70			* the documentation and/or other materials provided with the
71			* distribution.
72			*
73			* 3. All advertising materials mentioning features or use of this
74			* software must display the following acknowledgment:
75			* "This product includes software developed by the OpenSSL Project
76			* for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
77			*
78			* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
79			* endorse or promote products derived from this software without
80			* prior written permission. For written permission, please contact
81			* openssl-core@openssl.org.
82			*
83			* 5. Products derived from this software may not be called "OpenSSL"
84			* nor may "OpenSSL" appear in their names without prior written
85			* permission of the OpenSSL Project.
86			*
87			* 6. Redistributions of any form whatsoever must retain the following
88			* acknowledgment:
89			* "This product includes software developed by the OpenSSL Project
90			* for use in the OpenSSL Toolkit (http://www.openssl.org/)"
91			*
92			* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
93			* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
94			* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
95			* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
96			* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
97			* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
98			* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
99			* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
100			* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
101			* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
102			* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
103			* OF THE POSSIBILITY OF SUCH DAMAGE.
104			* ====================================================================
105			*
106			* This product includes cryptographic software written by Eric Young
107			* (eay@cryptsoft.com). This product includes software written by Tim
108			* Hudson (tjh@cryptsoft.com).
109			*
110			*/
111
112			#include <stdio.h>
113
114			#include <openssl/err.h>
115
116			#include "bn_lcl.h"
117
118			#define TABLE_SIZE 32
119
120			int
121			BN_mod_exp2_mont(BIGNUM rr, const BIGNUM a1, const BIGNUM *p1,
122			const BIGNUM a2, const BIGNUM p2, const BIGNUM m, BN_CTX ctx,
123			BN_MONT_CTX *in_mont)
124		2	{
125		2	int i, j, bits, b, bits1, bits2, ret = 0, wpos1, wpos2, window1, window2, wvalue1, wvalue2;
126		2	int r_is_one = 1;
127			BIGNUM d, r;
128			const BIGNUM *a_mod_m;
129			/* Tables of variables obtained from 'ctx' */
130			BIGNUM val1[TABLE_SIZE], val2[TABLE_SIZE];
131		2	BN_MONT_CTX *mont = NULL;
132
133			bn_check_top(a1);
134			bn_check_top(p1);
135			bn_check_top(a2);
136			bn_check_top(p2);
137			bn_check_top(m);
138
139	✗✓	2	if (!(m->d[0] & 1)) {
140			BNerr(BN_F_BN_MOD_EXP2_MONT, BN_R_CALLED_WITH_EVEN_MODULUS);
141			return (0);
142			}
143		2	bits1 = BN_num_bits(p1);
144		2	bits2 = BN_num_bits(p2);
145	✗✓	2	if ((bits1 == 0) && (bits2 == 0)) {
146			ret = BN_one(rr);
147			return ret;
148			}
149
150		2	bits = (bits1 > bits2) ? bits1 : bits2;
151
152		2	BN_CTX_start(ctx);
153	✗✓	2	if ((d = BN_CTX_get(ctx)) == NULL)
154			goto err;
155	✗✓	2	if ((r = BN_CTX_get(ctx)) == NULL)
156			goto err;
157	✗✓	2	if ((val1[0] = BN_CTX_get(ctx)) == NULL)
158			goto err;
159	✗✓	2	if ((val2[0] = BN_CTX_get(ctx)) == NULL)
160			goto err;
161
162	✓✗	2	if (in_mont != NULL)
163		2	mont = in_mont;
164			else {
165			if ((mont = BN_MONT_CTX_new()) == NULL)
166			goto err;
167			if (!BN_MONT_CTX_set(mont, m, ctx))
168			goto err;
169			}
170
171	✓✗✓✗ ✗✓✗✗	2	window1 = BN_window_bits_for_exponent_size(bits1);
172	✓✗✓✗ ✗✓✗✗	2	window2 = BN_window_bits_for_exponent_size(bits2);
173
174			/*
175			* Build table for a1: val1[i] := a1^(2*i + 1) mod m for i = 0 .. 2^(window1-1)
176			*/
177	✓✗✗✓	2	if (a1->neg \|\| BN_ucmp(a1, m) >= 0) {
178			if (!BN_mod(val1[0], a1, m, ctx))
179			goto err;
180			a_mod_m = val1[0];
181			} else
182		2	a_mod_m = a1;
183	✗✓	2	if (BN_is_zero(a_mod_m)) {
184			BN_zero(rr);
185			ret = 1;
186			goto err;
187			}
188
189	✗✓	2	if (!BN_to_montgomery(val1[0], a_mod_m, mont, ctx))
190			goto err;
191	✓✗	2	if (window1 > 1) {
192	✗✓	2	if (!BN_mod_mul_montgomery(d, val1[0], val1[0], mont, ctx))
193			goto err;
194
195		2	j = 1 << (window1 - 1);
196	✓✓	16	for (i = 1; i < j; i++) {
197	✓✗✓✗	14	if (((val1[i] = BN_CTX_get(ctx)) == NULL) \|\|
198			!BN_mod_mul_montgomery(val1[i], val1[i - 1],
199			d, mont, ctx))
200			goto err;
201			}
202			}
203
204
205			/*
206			* Build table for a2: val2[i] := a2^(2*i + 1) mod m for i = 0 .. 2^(window2-1)
207			*/
208	✓✗✗✓	2	if (a2->neg \|\| BN_ucmp(a2, m) >= 0) {
209			if (!BN_mod(val2[0], a2, m, ctx))
210			goto err;
211			a_mod_m = val2[0];
212			} else
213		2	a_mod_m = a2;
214	✗✓	2	if (BN_is_zero(a_mod_m)) {
215			BN_zero(rr);
216			ret = 1;
217			goto err;
218			}
219	✗✓	2	if (!BN_to_montgomery(val2[0], a_mod_m, mont, ctx))
220			goto err;
221	✓✗	2	if (window2 > 1) {
222	✗✓	2	if (!BN_mod_mul_montgomery(d, val2[0], val2[0], mont, ctx))
223			goto err;
224
225		2	j = 1 << (window2 - 1);
226	✓✓	16	for (i = 1; i < j; i++) {
227	✓✗✓✗	14	if (((val2[i] = BN_CTX_get(ctx)) == NULL) \|\|
228			!BN_mod_mul_montgomery(val2[i], val2[i - 1],
229			d, mont, ctx))
230			goto err;
231			}
232			}
233
234
235			/* Now compute the power product, using independent windows. */
236		2	r_is_one = 1;
237		2	wvalue1 = 0; /* The 'value' of the first window */
238		2	wvalue2 = 0; /* The 'value' of the second window */
239		2	wpos1 = 0; /* If wvalue1 > 0, the bottom bit of the first window */
240		2	wpos2 = 0; /* If wvalue2 > 0, the bottom bit of the second window */
241
242	✗✓	2	if (!BN_to_montgomery(r, BN_value_one(), mont, ctx))
243			goto err;
244	✓✓	320	for (b = bits - 1; b >= 0; b--) {
245	✓✓	318	if (!r_is_one) {
246	✗✓	313	if (!BN_mod_mul_montgomery(r, r,r, mont, ctx))
247			goto err;
248			}
249
250	✓✓	318	if (!wvalue1)
251	✓✓	186	if (BN_is_bit_set(p1, b)) {
252			/* consider bits b-window1+1 .. b for this window */
253		65	i = b - window1 + 1;
254	✓✓	193	while (!BN_is_bit_set(p1, i)) /* works for i<0 */
255		63	i++;
256		65	wpos1 = i;
257		65	wvalue1 = 1;
258	✓✓	197	for (i = b - 1; i >= wpos1; i--) {
259		132	wvalue1 <<= 1;
260	✓✓	132	if (BN_is_bit_set(p1, i))
261		92	wvalue1++;
262			}
263			}
264
265	✓✓	318	if (!wvalue2)
266	✓✓	191	if (BN_is_bit_set(p2, b)) {
267			/* consider bits b-window2+1 .. b for this window */
268		62	i = b - window2 + 1;
269	✓✓	183	while (!BN_is_bit_set(p2, i))
270		59	i++;
271		62	wpos2 = i;
272		62	wvalue2 = 1;
273	✓✓	189	for (i = b - 1; i >= wpos2; i--) {
274		127	wvalue2 <<= 1;
275	✓✓	127	if (BN_is_bit_set(p2, i))
276		93	wvalue2++;
277			}
278			}
279
280	✓✓	318	if (wvalue1 && b == wpos1) {
281			/* wvalue1 is odd and < 2^window1 */
282	✗✓	65	if (!BN_mod_mul_montgomery(r, r, val1[wvalue1 >> 1],
283			mont, ctx))
284			goto err;
285		65	wvalue1 = 0;
286		65	r_is_one = 0;
287			}
288
289	✓✓	318	if (wvalue2 && b == wpos2) {
290			/* wvalue2 is odd and < 2^window2 */
291	✗✓	62	if (!BN_mod_mul_montgomery(r, r, val2[wvalue2 >> 1],
292			mont, ctx))
293			goto err;
294		62	wvalue2 = 0;
295		62	r_is_one = 0;
296			}
297			}
298	✗✓	2	if (!BN_from_montgomery(rr, r,mont, ctx))
299			goto err;
300		2	ret = 1;
301
302		2	err:
303	✗✓	2	if ((in_mont == NULL) && (mont != NULL))
304			BN_MONT_CTX_free(mont);
305		2	BN_CTX_end(ctx);
306			bn_check_top(rr);
307		2	return (ret);
308			}