Head

GCC Code Coverage Report

Directory:	./		Exec	Total	Coverage
File:	lib/libcrypto/bn/bn_sqr.c	Lines:	82	94	87.2 %
Date:	2017-11-07	Branches:	42	53	79.2 %


/* $OpenBSD: bn_sqr.c,v 1.12 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.]
 */

#include <stdio.h>
#include <string.h>

#include "bn_lcl.h"

/* r must not be a */
/* I've just gone over this and it is now %20 faster on x86 - eay - 27 Jun 96 */
int
BN_sqr(BIGNUM *r, const BIGNUM *a, BN_CTX *ctx)
{
	int max, al;
	int ret = 0;
	BIGNUM *tmp, *rr;

#ifdef BN_COUNT
	fprintf(stderr, "BN_sqr %d * %d\n", a->top, a->top);
#endif
	bn_check_top(a);

	al = a->top;
	if (al <= 0) {
		r->top = 0;
		r->neg = 0;
		return 1;
	}

	BN_CTX_start(ctx);
	rr = (a != r) ? r : BN_CTX_get(ctx);
	tmp = BN_CTX_get(ctx);
	if (rr == NULL || tmp == NULL)
		goto err;

	max = 2 * al; /* Non-zero (from above) */
	if (bn_wexpand(rr, max) == NULL)
		goto err;

	if (al == 4) {
#ifndef BN_SQR_COMBA
		BN_ULONG t[8];
		bn_sqr_normal(rr->d, a->d, 4, t);
#else
		bn_sqr_comba4(rr->d, a->d);
#endif
	} else if (al == 8) {
#ifndef BN_SQR_COMBA
		BN_ULONG t[16];
		bn_sqr_normal(rr->d, a->d, 8, t);
#else
		bn_sqr_comba8(rr->d, a->d);
#endif
	} else {
#if defined(BN_RECURSION)
		if (al < BN_SQR_RECURSIVE_SIZE_NORMAL) {
			BN_ULONG t[BN_SQR_RECURSIVE_SIZE_NORMAL*2];
			bn_sqr_normal(rr->d, a->d, al, t);
		} else {
			int j, k;

			j = BN_num_bits_word((BN_ULONG)al);
			j = 1 << (j - 1);
			k = j + j;
			if (al == j) {
				if (bn_wexpand(tmp, k * 2) == NULL)
					goto err;
				bn_sqr_recursive(rr->d, a->d, al, tmp->d);
			} else {
				if (bn_wexpand(tmp, max) == NULL)
					goto err;
				bn_sqr_normal(rr->d, a->d, al, tmp->d);
			}
		}
#else
		if (bn_wexpand(tmp, max) == NULL)
			goto err;
		bn_sqr_normal(rr->d, a->d, al, tmp->d);
#endif
	}

	rr->neg = 0;
	/* If the most-significant half of the top word of 'a' is zero, then
	 * the square of 'a' will max-1 words. */
	if (a->d[al - 1] == (a->d[al - 1] & BN_MASK2l))
		rr->top = max - 1;
	else
		rr->top = max;
	if (rr != r)
		BN_copy(r, rr);
	ret = 1;

err:
	bn_check_top(rr);
	bn_check_top(tmp);
	BN_CTX_end(ctx);
	return (ret);
}

/* tmp must have 2*n words */
void
bn_sqr_normal(BN_ULONG *r, const BN_ULONG *a, int n, BN_ULONG *tmp)
{
	int i, j, max;
	const BN_ULONG *ap;
	BN_ULONG *rp;

	max = n * 2;
	ap = a;
	rp = r;
	rp[0] = rp[max - 1] = 0;
	rp++;
	j = n;

	if (--j > 0) {
		ap++;
		rp[j] = bn_mul_words(rp, ap, j, ap[-1]);
		rp += 2;
	}

	for (i = n - 2; i > 0; i--) {
		j--;
		ap++;
		rp[j] = bn_mul_add_words(rp, ap, j, ap[-1]);
		rp += 2;
	}

	bn_add_words(r, r, r, max);

	/* There will not be a carry */

	bn_sqr_words(tmp, a, n);

	bn_add_words(r, r, tmp, max);
}

#ifdef BN_RECURSION
/* r is 2*n words in size,
 * a and b are both n words in size.    (There's not actually a 'b' here ...)
 * n must be a power of 2.
 * We multiply and return the result.
 * t must be 2*n words in size
 * We calculate
 * a[0]*b[0]
 * a[0]*b[0]+a[1]*b[1]+(a[0]-a[1])*(b[1]-b[0])
 * a[1]*b[1]
 */
void
bn_sqr_recursive(BN_ULONG *r, const BN_ULONG *a, int n2, BN_ULONG *t)
{
	int n = n2 / 2;
	int zero, c1;
	BN_ULONG ln, lo, *p;

#ifdef BN_COUNT
	fprintf(stderr, " bn_sqr_recursive %d * %d\n", n2, n2);
#endif
	if (n2 == 4) {
#ifndef BN_SQR_COMBA
		bn_sqr_normal(r, a, 4, t);
#else
		bn_sqr_comba4(r, a);
#endif
		return;
	} else if (n2 == 8) {
#ifndef BN_SQR_COMBA
		bn_sqr_normal(r, a, 8, t);
#else
		bn_sqr_comba8(r, a);
#endif
		return;
	}
	if (n2 < BN_SQR_RECURSIVE_SIZE_NORMAL) {
		bn_sqr_normal(r, a, n2, t);
		return;
	}
	/* r=(a[0]-a[1])*(a[1]-a[0]) */
	c1 = bn_cmp_words(a, &(a[n]), n);
	zero = 0;
	if (c1 > 0)
		bn_sub_words(t, a, &(a[n]), n);
	else if (c1 < 0)
		bn_sub_words(t, &(a[n]), a, n);
	else
		zero = 1;

	/* The result will always be negative unless it is zero */
	p = &(t[n2*2]);

	if (!zero)
		bn_sqr_recursive(&(t[n2]), t, n, p);
	else
		memset(&(t[n2]), 0, n2 * sizeof(BN_ULONG));
	bn_sqr_recursive(r, a, n, p);
	bn_sqr_recursive(&(r[n2]), &(a[n]), n, p);

	/* t[32] holds (a[0]-a[1])*(a[1]-a[0]), it is negative or zero
	 * r[10] holds (a[0]*b[0])
	 * r[32] holds (b[1]*b[1])
	 */

	c1 = (int)(bn_add_words(t, r, &(r[n2]), n2));

	/* t[32] is negative */
	c1 -= (int)(bn_sub_words(&(t[n2]), t, &(t[n2]), n2));

	/* t[32] holds (a[0]-a[1])*(a[1]-a[0])+(a[0]*a[0])+(a[1]*a[1])
	 * r[10] holds (a[0]*a[0])
	 * r[32] holds (a[1]*a[1])
	 * c1 holds the carry bits
	 */
	c1 += (int)(bn_add_words(&(r[n]), &(r[n]), &(t[n2]), n2));
	if (c1) {
		p = &(r[n + n2]);
		lo= *p;
		ln = (lo + c1) & BN_MASK2;
		*p = ln;

		/* The overflow will stop before we over write
		 * words we should not overwrite */
		if (ln < (BN_ULONG)c1) {
			do {
				p++;
				lo= *p;
				ln = (lo + 1) & BN_MASK2;
				*p = ln;
			} while (ln == 0);
		}
	}
}
#endif


Generated by: GCOVR (Version 3.3)

Line	Branch	Exec	Source
1			/* $OpenBSD: bn_sqr.c,v 1.12 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			#include <stdio.h>
60			#include <string.h>
61
62			#include "bn_lcl.h"
63
64			/* r must not be a */
65			/* I've just gone over this and it is now %20 faster on x86 - eay - 27 Jun 96 */
66			int
67			BN_sqr(BIGNUM r, const BIGNUM a, BN_CTX *ctx)
68			{
69			int max, al;
70			int ret = 0;
71			BIGNUM tmp, rr;
72
73			#ifdef BN_COUNT
74			fprintf(stderr, "BN_sqr %d * %d\n", a->top, a->top);
75			#endif
76			bn_check_top(a);
77
78		4871654	al = a->top;
79	✓✓	2435827	if (al <= 0) {
80		11551	r->top = 0;
81		11551	r->neg = 0;
82		11551	return 1;
83			}
84
85		2424276	BN_CTX_start(ctx);
86	✓✓	7272828	rr = (a != r) ? r : BN_CTX_get(ctx);
87		2424276	tmp = BN_CTX_get(ctx);
88	✓✗	2424276	if (rr == NULL \|\| tmp == NULL)
89			goto err;
90
91		2424276	max = 2 * al; /* Non-zero (from above) */
92	✓✓✓✗	4890101	if (bn_wexpand(rr, max) == NULL)
93			goto err;
94
95	✓✓	2424276	if (al == 4) {
96			#ifndef BN_SQR_COMBA
97			BN_ULONG t[8];
98			bn_sqr_normal(rr->d, a->d, 4, t);
99			#else
100		58881	bn_sqr_comba4(rr->d, a->d);
101			#endif
102	✓✓	2424276	} else if (al == 8) {
103			#ifndef BN_SQR_COMBA
104			BN_ULONG t[16];
105			bn_sqr_normal(rr->d, a->d, 8, t);
106			#else
107		729405	bn_sqr_comba8(rr->d, a->d);
108			#endif
109		729405	} else {
110			#if defined(BN_RECURSION)
111	✓✓	1635990	if (al < BN_SQR_RECURSIVE_SIZE_NORMAL) {
112		1574889	BN_ULONG t[BN_SQR_RECURSIVE_SIZE_NORMAL*2];
113		1574889	bn_sqr_normal(rr->d, a->d, al, t);
114		1574889	} else {
115			int j, k;
116
117		61101	j = BN_num_bits_word((BN_ULONG)al);
118		61101	j = 1 << (j - 1);
119		61101	k = j + j;
120	✓✓	61101	if (al == j) {
121	✓✓✗✓	144315	if (bn_wexpand(tmp, k * 2) == NULL)
122			goto err;
123		60971	bn_sqr_recursive(rr->d, a->d, al, tmp->d);
124		60971	} else {
125	✓✓✗✓	328	if (bn_wexpand(tmp, max) == NULL)
126			goto err;
127		130	bn_sqr_normal(rr->d, a->d, al, tmp->d);
128			}
129	✓✓✓	61101	}
130			#else
131			if (bn_wexpand(tmp, max) == NULL)
132			goto err;
133			bn_sqr_normal(rr->d, a->d, al, tmp->d);
134			#endif
135			}
136
137		2424276	rr->neg = 0;
138			/* If the most-significant half of the top word of 'a' is zero, then
139			* the square of 'a' will max-1 words. */
140		4848552	if (a->d[al - 1] == (a->d[al - 1] & BN_MASK2l))
141		2424276	rr->top = max - 1;
142			else
143			rr->top = max;
144	✓✓	2424276	if (rr != r)
145		54132	BN_copy(r, rr);
146		2424276	ret = 1;
147
148			err:
149			bn_check_top(rr);
150			bn_check_top(tmp);
151		2424276	BN_CTX_end(ctx);
152		2424276	return (ret);
153		2435827	}
154
155			/* tmp must have 2n words /
156			void
157			bn_sqr_normal(BN_ULONG r, const BN_ULONG a, int n, BN_ULONG *tmp)
158			{
159			int i, j, max;
160			const BN_ULONG *ap;
161			BN_ULONG *rp;
162
163		3150038	max = n * 2;
164			ap = a;
165			rp = r;
166		1575019	rp[0] = rp[max - 1] = 0;
167		1575019	rp++;
168			j = n;
169
170	✓✓	1575019	if (--j > 0) {
171		383811	ap++;
172		383811	rp[j] = bn_mul_words(rp, ap, j, ap[-1]);
173		383811	rp += 2;
174		383811	}
175
176	✓✓	5571998	for (i = n - 2; i > 0; i--) {
177		1210980	j--;
178		1210980	ap++;
179		1210980	rp[j] = bn_mul_add_words(rp, ap, j, ap[-1]);
180		1210980	rp += 2;
181			}
182
183		1575019	bn_add_words(r, r, r, max);
184
185			/* There will not be a carry */
186
187		1575019	bn_sqr_words(tmp, a, n);
188
189		1575019	bn_add_words(r, r, tmp, max);
190		1575019	}
191
192			#ifdef BN_RECURSION
193			/* r is 2*n words in size,
194			* a and b are both n words in size. (There's not actually a 'b' here ...)
195			* n must be a power of 2.
196			* We multiply and return the result.
197			* t must be 2*n words in size
198			* We calculate
199			* a[0]*b[0]
200			* a[0]b[0]+a[1]b[1]+(a[0]-a[1])*(b[1]-b[0])
201			* a[1]*b[1]
202			*/
203			void
204			bn_sqr_recursive(BN_ULONG r, const BN_ULONG a, int n2, BN_ULONG *t)
205			{
206		1185664	int n = n2 / 2;
207			int zero, c1;
208			BN_ULONG ln, lo, *p;
209
210			#ifdef BN_COUNT
211			fprintf(stderr, " bn_sqr_recursive %d * %d\n", n2, n2);
212			#endif
213	✗✓	592832	if (n2 == 4) {
214			#ifndef BN_SQR_COMBA
215			bn_sqr_normal(r, a, 4, t);
216			#else
217			bn_sqr_comba4(r, a);
218			#endif
219			return;
220	✓✓	592832	} else if (n2 == 8) {
221			#ifndef BN_SQR_COMBA
222			bn_sqr_normal(r, a, 8, t);
223			#else
224		415545	bn_sqr_comba8(r, a);
225			#endif
226		415545	return;
227			}
228	✗✓	177287	if (n2 < BN_SQR_RECURSIVE_SIZE_NORMAL) {
229			bn_sqr_normal(r, a, n2, t);
230			return;
231			}
232			/* r=(a[0]-a[1])(a[1]-a[0]) /
233		177287	c1 = bn_cmp_words(a, &(a[n]), n);
234			zero = 0;
235	✓✓	177287	if (c1 > 0)
236		108583	bn_sub_words(t, a, &(a[n]), n);
237	✓✗	68704	else if (c1 < 0)
238		68704	bn_sub_words(t, &(a[n]), a, n);
239			else
240			zero = 1;
241
242			/* The result will always be negative unless it is zero */
243		177287	p = &(t[n2*2]);
244
245	✓✗	177287	if (!zero)
246		177287	bn_sqr_recursive(&(t[n2]), t, n, p);
247			else
248			memset(&(t[n2]), 0, n2 * sizeof(BN_ULONG));
249		177287	bn_sqr_recursive(r, a, n, p);
250		177287	bn_sqr_recursive(&(r[n2]), &(a[n]), n, p);
251
252			/* t[32] holds (a[0]-a[1])*(a[1]-a[0]), it is negative or zero
253			* r[10] holds (a[0]*b[0])
254			* r[32] holds (b[1]*b[1])
255			*/
256
257		177287	c1 = (int)(bn_add_words(t, r, &(r[n2]), n2));
258
259			/* t[32] is negative */
260		177287	c1 -= (int)(bn_sub_words(&(t[n2]), t, &(t[n2]), n2));
261
262			/* t[32] holds (a[0]-a[1])(a[1]-a[0])+(a[0]a[0])+(a[1]*a[1])
263			* r[10] holds (a[0]*a[0])
264			* r[32] holds (a[1]*a[1])
265			* c1 holds the carry bits
266			*/
267		177287	c1 += (int)(bn_add_words(&(r[n]), &(r[n]), &(t[n2]), n2));
268	✓✓	177287	if (c1) {
269		65404	p = &(r[n + n2]);
270		65404	lo= *p;
271		65404	ln = (lo + c1) & BN_MASK2;
272		65404	*p = ln;
273
274			/* The overflow will stop before we over write
275			* words we should not overwrite */
276	✗✓	65404	if (ln < (BN_ULONG)c1) {
277			do {
278			p++;
279			lo= *p;
280			ln = (lo + 1) & BN_MASK2;
281			*p = ln;
282			} while (ln == 0);
283			}
284			}
285		770119	}
286			#endif