Adam Langley | 95c29f3 | 2014-06-20 12:00:00 -0700 | [diff] [blame^] | 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 "internal.h" |
| 60 | |
| 61 | int BN_lshift(BIGNUM *r, const BIGNUM *a, int n) { |
| 62 | int i, nw, lb, rb; |
| 63 | BN_ULONG *t, *f; |
| 64 | BN_ULONG l; |
| 65 | |
| 66 | r->neg = a->neg; |
| 67 | nw = n / BN_BITS2; |
| 68 | if (bn_wexpand(r, a->top + nw + 1) == NULL) { |
| 69 | return 0; |
| 70 | } |
| 71 | lb = n % BN_BITS2; |
| 72 | rb = BN_BITS2 - lb; |
| 73 | f = a->d; |
| 74 | t = r->d; |
| 75 | t[a->top + nw] = 0; |
| 76 | if (lb == 0) { |
| 77 | for (i = a->top - 1; i >= 0; i--) { |
| 78 | t[nw + i] = f[i]; |
| 79 | } |
| 80 | } else { |
| 81 | for (i = a->top - 1; i >= 0; i--) { |
| 82 | l = f[i]; |
| 83 | t[nw + i + 1] |= (l >> rb) & BN_MASK2; |
| 84 | t[nw + i] = (l << lb) & BN_MASK2; |
| 85 | } |
| 86 | } |
| 87 | memset(t, 0, nw * sizeof(t[0])); |
| 88 | r->top = a->top + nw + 1; |
| 89 | bn_correct_top(r); |
| 90 | |
| 91 | return 1; |
| 92 | } |
| 93 | |
| 94 | int BN_lshift1(BIGNUM *r, const BIGNUM *a) { |
| 95 | BN_ULONG *ap, *rp, t, c; |
| 96 | int i; |
| 97 | |
| 98 | if (r != a) { |
| 99 | r->neg = a->neg; |
| 100 | if (bn_wexpand(r, a->top + 1) == NULL) { |
| 101 | return 0; |
| 102 | } |
| 103 | r->top = a->top; |
| 104 | } else { |
| 105 | if (bn_wexpand(r, a->top + 1) == NULL) { |
| 106 | return 0; |
| 107 | } |
| 108 | } |
| 109 | ap = a->d; |
| 110 | rp = r->d; |
| 111 | c = 0; |
| 112 | for (i = 0; i < a->top; i++) { |
| 113 | t = *(ap++); |
| 114 | *(rp++) = ((t << 1) | c) & BN_MASK2; |
| 115 | c = (t & BN_TBIT) ? 1 : 0; |
| 116 | } |
| 117 | if (c) { |
| 118 | *rp = 1; |
| 119 | r->top++; |
| 120 | } |
| 121 | |
| 122 | return 1; |
| 123 | } |
| 124 | |
| 125 | int BN_rshift(BIGNUM *r, const BIGNUM *a, int n) { |
| 126 | int i, j, nw, lb, rb; |
| 127 | BN_ULONG *t, *f; |
| 128 | BN_ULONG l, tmp; |
| 129 | |
| 130 | nw = n / BN_BITS2; |
| 131 | rb = n % BN_BITS2; |
| 132 | lb = BN_BITS2 - rb; |
| 133 | if (nw >= a->top || a->top == 0) { |
| 134 | BN_zero(r); |
| 135 | return 1; |
| 136 | } |
| 137 | i = (BN_num_bits(a) - n + (BN_BITS2 - 1)) / BN_BITS2; |
| 138 | if (r != a) { |
| 139 | r->neg = a->neg; |
| 140 | if (bn_wexpand(r, i) == NULL) { |
| 141 | return 0; |
| 142 | } |
| 143 | } else { |
| 144 | if (n == 0) { |
| 145 | return 1; /* or the copying loop will go berserk */ |
| 146 | } |
| 147 | } |
| 148 | |
| 149 | f = &(a->d[nw]); |
| 150 | t = r->d; |
| 151 | j = a->top - nw; |
| 152 | r->top = i; |
| 153 | |
| 154 | if (rb == 0) { |
| 155 | for (i = j; i != 0; i--) { |
| 156 | *(t++) = *(f++); |
| 157 | } |
| 158 | } else { |
| 159 | l = *(f++); |
| 160 | for (i = j - 1; i != 0; i--) { |
| 161 | tmp = (l >> rb) & BN_MASK2; |
| 162 | l = *(f++); |
| 163 | *(t++) = (tmp | (l << lb)) & BN_MASK2; |
| 164 | } |
| 165 | if ((l = (l >> rb) & BN_MASK2)) { |
| 166 | *(t) = l; |
| 167 | } |
| 168 | } |
| 169 | |
| 170 | return 1; |
| 171 | } |
| 172 | |
| 173 | int BN_rshift1(BIGNUM *r, const BIGNUM *a) { |
| 174 | BN_ULONG *ap, *rp, t, c; |
| 175 | int i, j; |
| 176 | |
| 177 | if (BN_is_zero(a)) { |
| 178 | BN_zero(r); |
| 179 | return 1; |
| 180 | } |
| 181 | i = a->top; |
| 182 | ap = a->d; |
| 183 | j = i - (ap[i - 1] == 1); |
| 184 | if (a != r) { |
| 185 | if (bn_wexpand(r, j) == NULL) { |
| 186 | return 0; |
| 187 | } |
| 188 | r->neg = a->neg; |
| 189 | } |
| 190 | rp = r->d; |
| 191 | t = ap[--i]; |
| 192 | c = (t & 1) ? BN_TBIT : 0; |
| 193 | if (t >>= 1) { |
| 194 | rp[i] = t; |
| 195 | } |
| 196 | while (i > 0) { |
| 197 | t = ap[--i]; |
| 198 | rp[i] = ((t >> 1) & BN_MASK2) | c; |
| 199 | c = (t & 1) ? BN_TBIT : 0; |
| 200 | } |
| 201 | r->top = j; |
| 202 | |
| 203 | return 1; |
| 204 | } |
| 205 | |
| 206 | int BN_set_bit(BIGNUM *a, int n) { |
| 207 | int i, j, k; |
| 208 | |
| 209 | if (n < 0) { |
| 210 | return 0; |
| 211 | } |
| 212 | |
| 213 | i = n / BN_BITS2; |
| 214 | j = n % BN_BITS2; |
| 215 | if (a->top <= i) { |
| 216 | if (bn_wexpand(a, i + 1) == NULL) { |
| 217 | return 0; |
| 218 | } |
| 219 | for (k = a->top; k < i + 1; k++) { |
| 220 | a->d[k] = 0; |
| 221 | } |
| 222 | a->top = i + 1; |
| 223 | } |
| 224 | |
| 225 | a->d[i] |= (((BN_ULONG)1) << j); |
| 226 | |
| 227 | return 1; |
| 228 | } |
| 229 | |
| 230 | int BN_clear_bit(BIGNUM *a, int n) { |
| 231 | int i, j; |
| 232 | |
| 233 | if (n < 0) { |
| 234 | return 0; |
| 235 | } |
| 236 | |
| 237 | i = n / BN_BITS2; |
| 238 | j = n % BN_BITS2; |
| 239 | if (a->top <= i) { |
| 240 | return 0; |
| 241 | } |
| 242 | |
| 243 | a->d[i] &= (~(((BN_ULONG)1) << j)); |
| 244 | bn_correct_top(a); |
| 245 | return 1; |
| 246 | } |
| 247 | |
| 248 | int BN_is_bit_set(const BIGNUM *a, int n) { |
| 249 | int i, j; |
| 250 | |
| 251 | if (n < 0) { |
| 252 | return 0; |
| 253 | } |
| 254 | i = n / BN_BITS2; |
| 255 | j = n % BN_BITS2; |
| 256 | if (a->top <= i) { |
| 257 | return 0; |
| 258 | } |
| 259 | |
| 260 | return (a->d[i]>>j)&1; |
| 261 | } |
| 262 | |
| 263 | int BN_mask_bits(BIGNUM *a, int n) { |
| 264 | int b, w; |
| 265 | |
| 266 | if (n < 0) { |
| 267 | return 0; |
| 268 | } |
| 269 | |
| 270 | w = n / BN_BITS2; |
| 271 | b = n % BN_BITS2; |
| 272 | if (w >= a->top) { |
| 273 | return 0; |
| 274 | } |
| 275 | if (b == 0) { |
| 276 | a->top = w; |
| 277 | } else { |
| 278 | a->top = w + 1; |
| 279 | a->d[w] &= ~(BN_MASK2 << b); |
| 280 | } |
| 281 | |
| 282 | bn_correct_top(a); |
| 283 | return 1; |
| 284 | } |