1 /* Copyright (C) 1995-1998 Eric Young (eay (at) cryptsoft.com) 2 * All rights reserved. 3 * 4 * This package is an SSL implementation written 5 * by Eric Young (eay (at) 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 (at) 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 (at) 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 (at) 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 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 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 } 134 135 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 } 154 155 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 } 176 177 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 } 187 188 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 } 198 199 int BN_is_zero(const BIGNUM *bn) { 200 return bn->top == 0; 201 } 202 203 int BN_is_one(const BIGNUM *bn) { 204 return bn->neg == 0 && BN_abs_is_word(bn, 1); 205 } 206 207 int BN_is_word(const BIGNUM *bn, BN_ULONG w) { 208 return BN_abs_is_word(bn, w) && (w == 0 || bn->neg == 0); 209 } 210 211 int BN_is_odd(const BIGNUM *bn) { 212 return bn->top > 0 && (bn->d[0] & 1) == 1; 213 } 214 215 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 } 228 229 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