1 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
2 * All rights reserved.
3 *
4 * This package is an SSL implementation written
5 * by Eric Young (eay@cryptsoft.com).
6 * The implementation was written so as to conform with Netscapes SSL.
7 *
8 * This library is free for commercial and non-commercial use as long as
9 * the following conditions are aheared to. The following conditions
10 * apply to all code found in this distribution, be it the RC4, RSA,
11 * lhash, DES, etc., code; not just the SSL code. The SSL documentation
12 * included with this distribution is covered by the same copyright terms
13 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
14 *
15 * Copyright remains Eric Young's, and as such any Copyright notices in
16 * the code are not to be removed.
17 * If this package is used in a product, Eric Young should be given attribution
18 * as the author of the parts of the library used.
19 * This can be in the form of a textual message at program startup or
20 * in documentation (online or textual) provided with the package.
21 *
22 * Redistribution and use in source and binary forms, with or without
23 * modification, are permitted provided that the following conditions
24 * are met:
25 * 1. Redistributions of source code must retain the copyright
26 * notice, this list of conditions and the following disclaimer.
27 * 2. Redistributions in binary form must reproduce the above copyright
28 * notice, this list of conditions and the following disclaimer in the
29 * documentation and/or other materials provided with the distribution.
30 * 3. All advertising materials mentioning features or use of this software
31 * must display the following acknowledgement:
32 * "This product includes cryptographic software written by
33 * Eric Young (eay@cryptsoft.com)"
34 * The word 'cryptographic' can be left out if the rouines from the library
35 * being used are not cryptographic related :-).
36 * 4. If you include any Windows specific code (or a derivative thereof) from
37 * the apps directory (application code) you must include an acknowledgement:
38 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
39 *
40 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
41 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
42 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
43 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
44 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
45 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
46 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
48 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
49 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
50 * SUCH DAMAGE.
51 *
52 * The licence and distribution terms for any publically available version or
53 * derivative of this code cannot be changed. i.e. this code cannot simply be
54 * copied and put under another distribution licence
55 * [including the GNU Public Licence.] */
56
57 #include <openssl/bn.h>
58
59 #include <openssl/mem.h>
60
61 #include "internal.h"
62
63
BN_ucmp(const BIGNUM * a,const BIGNUM * b)64 int BN_ucmp(const BIGNUM *a, const BIGNUM *b) {
65 int i;
66 BN_ULONG t1, t2, *ap, *bp;
67
68 i = a->top - b->top;
69 if (i != 0) {
70 return i;
71 }
72
73 ap = a->d;
74 bp = b->d;
75 for (i = a->top - 1; i >= 0; i--) {
76 t1 = ap[i];
77 t2 = bp[i];
78 if (t1 != t2) {
79 return (t1 > t2) ? 1 : -1;
80 }
81 }
82
83 return 0;
84 }
85
BN_cmp(const BIGNUM * a,const BIGNUM * b)86 int BN_cmp(const BIGNUM *a, const BIGNUM *b) {
87 int i;
88 int gt, lt;
89 BN_ULONG t1, t2;
90
91 if ((a == NULL) || (b == NULL)) {
92 if (a != NULL) {
93 return -1;
94 } else if (b != NULL) {
95 return 1;
96 } else {
97 return 0;
98 }
99 }
100
101 if (a->neg != b->neg) {
102 if (a->neg) {
103 return -1;
104 }
105 return 1;
106 }
107 if (a->neg == 0) {
108 gt = 1;
109 lt = -1;
110 } else {
111 gt = -1;
112 lt = 1;
113 }
114
115 if (a->top > b->top) {
116 return gt;
117 }
118 if (a->top < b->top) {
119 return lt;
120 }
121
122 for (i = a->top - 1; i >= 0; i--) {
123 t1 = a->d[i];
124 t2 = b->d[i];
125 if (t1 > t2) {
126 return gt;
127 } if (t1 < t2) {
128 return lt;
129 }
130 }
131
132 return 0;
133 }
134
bn_cmp_words(const BN_ULONG * a,const BN_ULONG * b,int n)135 int bn_cmp_words(const BN_ULONG *a, const BN_ULONG *b, int n) {
136 int i;
137 BN_ULONG aa, bb;
138
139 aa = a[n - 1];
140 bb = b[n - 1];
141 if (aa != bb) {
142 return (aa > bb) ? 1 : -1;
143 }
144
145 for (i = n - 2; i >= 0; i--) {
146 aa = a[i];
147 bb = b[i];
148 if (aa != bb) {
149 return (aa > bb) ? 1 : -1;
150 }
151 }
152 return 0;
153 }
154
bn_cmp_part_words(const BN_ULONG * a,const BN_ULONG * b,int cl,int dl)155 int bn_cmp_part_words(const BN_ULONG *a, const BN_ULONG *b, int cl, int dl) {
156 int n, i;
157 n = cl - 1;
158
159 if (dl < 0) {
160 for (i = dl; i < 0; i++) {
161 if (b[n - i] != 0) {
162 return -1; /* a < b */
163 }
164 }
165 }
166 if (dl > 0) {
167 for (i = dl; i > 0; i--) {
168 if (a[n + i] != 0) {
169 return 1; /* a > b */
170 }
171 }
172 }
173
174 return bn_cmp_words(a, b, cl);
175 }
176
BN_abs_is_word(const BIGNUM * bn,BN_ULONG w)177 int BN_abs_is_word(const BIGNUM *bn, BN_ULONG w) {
178 switch (bn->top) {
179 case 1:
180 return bn->d[0] == w;
181 case 0:
182 return w == 0;
183 default:
184 return 0;
185 }
186 }
187
BN_cmp_word(const BIGNUM * a,BN_ULONG b)188 int BN_cmp_word(const BIGNUM *a, BN_ULONG b) {
189 BIGNUM b_bn;
190 BN_init(&b_bn);
191
192 b_bn.d = &b;
193 b_bn.top = b > 0;
194 b_bn.dmax = 1;
195 b_bn.flags = BN_FLG_STATIC_DATA;
196 return BN_cmp(a, &b_bn);
197 }
198
BN_is_zero(const BIGNUM * bn)199 int BN_is_zero(const BIGNUM *bn) {
200 return bn->top == 0;
201 }
202
BN_is_one(const BIGNUM * bn)203 int BN_is_one(const BIGNUM *bn) {
204 return bn->neg == 0 && BN_abs_is_word(bn, 1);
205 }
206
BN_is_word(const BIGNUM * bn,BN_ULONG w)207 int BN_is_word(const BIGNUM *bn, BN_ULONG w) {
208 return BN_abs_is_word(bn, w) && (w == 0 || bn->neg == 0);
209 }
210
BN_is_odd(const BIGNUM * bn)211 int BN_is_odd(const BIGNUM *bn) {
212 return bn->top > 0 && (bn->d[0] & 1) == 1;
213 }
214
BN_is_pow2(const BIGNUM * bn)215 int BN_is_pow2(const BIGNUM *bn) {
216 if (bn->top == 0 || bn->neg) {
217 return 0;
218 }
219
220 for (int i = 0; i < bn->top - 1; i++) {
221 if (bn->d[i] != 0) {
222 return 0;
223 }
224 }
225
226 return 0 == (bn->d[bn->top-1] & (bn->d[bn->top-1] - 1));
227 }
228
BN_equal_consttime(const BIGNUM * a,const BIGNUM * b)229 int BN_equal_consttime(const BIGNUM *a, const BIGNUM *b) {
230 if (a->top != b->top) {
231 return 0;
232 }
233
234 int limbs_are_equal =
235 CRYPTO_memcmp(a->d, b->d, (size_t)a->top * sizeof(a->d[0])) == 0;
236
237 return constant_time_select_int(constant_time_eq_int(a->neg, b->neg),
238 limbs_are_equal, 0);
239 }
240