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 <string.h>
60
61 #include <openssl/err.h>
62
63 #include "internal.h"
64
65
BN_lshift(BIGNUM * r,const BIGNUM * a,int n)66 int BN_lshift(BIGNUM *r, const BIGNUM *a, int n) {
67 int i, nw, lb, rb;
68 BN_ULONG *t, *f;
69 BN_ULONG l;
70
71 if (n < 0) {
72 OPENSSL_PUT_ERROR(BN, BN_R_NEGATIVE_NUMBER);
73 return 0;
74 }
75
76 r->neg = a->neg;
77 nw = n / BN_BITS2;
78 if (!bn_wexpand(r, a->top + nw + 1)) {
79 return 0;
80 }
81 lb = n % BN_BITS2;
82 rb = BN_BITS2 - lb;
83 f = a->d;
84 t = r->d;
85 t[a->top + nw] = 0;
86 if (lb == 0) {
87 for (i = a->top - 1; i >= 0; i--) {
88 t[nw + i] = f[i];
89 }
90 } else {
91 for (i = a->top - 1; i >= 0; i--) {
92 l = f[i];
93 t[nw + i + 1] |= (l >> rb) & BN_MASK2;
94 t[nw + i] = (l << lb) & BN_MASK2;
95 }
96 }
97 OPENSSL_memset(t, 0, nw * sizeof(t[0]));
98 r->top = a->top + nw + 1;
99 bn_correct_top(r);
100
101 return 1;
102 }
103
BN_lshift1(BIGNUM * r,const BIGNUM * a)104 int BN_lshift1(BIGNUM *r, const BIGNUM *a) {
105 BN_ULONG *ap, *rp, t, c;
106 int i;
107
108 if (r != a) {
109 r->neg = a->neg;
110 if (!bn_wexpand(r, a->top + 1)) {
111 return 0;
112 }
113 r->top = a->top;
114 } else {
115 if (!bn_wexpand(r, a->top + 1)) {
116 return 0;
117 }
118 }
119 ap = a->d;
120 rp = r->d;
121 c = 0;
122 for (i = 0; i < a->top; i++) {
123 t = *(ap++);
124 *(rp++) = ((t << 1) | c) & BN_MASK2;
125 c = (t & BN_TBIT) ? 1 : 0;
126 }
127 if (c) {
128 *rp = 1;
129 r->top++;
130 }
131
132 return 1;
133 }
134
BN_rshift(BIGNUM * r,const BIGNUM * a,int n)135 int BN_rshift(BIGNUM *r, const BIGNUM *a, int n) {
136 int i, j, nw, lb, rb;
137 BN_ULONG *t, *f;
138 BN_ULONG l, tmp;
139
140 if (n < 0) {
141 OPENSSL_PUT_ERROR(BN, BN_R_NEGATIVE_NUMBER);
142 return 0;
143 }
144
145 nw = n / BN_BITS2;
146 rb = n % BN_BITS2;
147 lb = BN_BITS2 - rb;
148 if (nw >= a->top || a->top == 0) {
149 BN_zero(r);
150 return 1;
151 }
152 i = (BN_num_bits(a) - n + (BN_BITS2 - 1)) / BN_BITS2;
153 if (r != a) {
154 r->neg = a->neg;
155 if (!bn_wexpand(r, i)) {
156 return 0;
157 }
158 } else {
159 if (n == 0) {
160 return 1; /* or the copying loop will go berserk */
161 }
162 }
163
164 f = &(a->d[nw]);
165 t = r->d;
166 j = a->top - nw;
167 r->top = i;
168
169 if (rb == 0) {
170 for (i = j; i != 0; i--) {
171 *(t++) = *(f++);
172 }
173 } else {
174 l = *(f++);
175 for (i = j - 1; i != 0; i--) {
176 tmp = (l >> rb) & BN_MASK2;
177 l = *(f++);
178 *(t++) = (tmp | (l << lb)) & BN_MASK2;
179 }
180 if ((l = (l >> rb) & BN_MASK2)) {
181 *(t) = l;
182 }
183 }
184
185 if (r->top == 0) {
186 r->neg = 0;
187 }
188
189 return 1;
190 }
191
BN_rshift1(BIGNUM * r,const BIGNUM * a)192 int BN_rshift1(BIGNUM *r, const BIGNUM *a) {
193 BN_ULONG *ap, *rp, t, c;
194 int i, j;
195
196 if (BN_is_zero(a)) {
197 BN_zero(r);
198 return 1;
199 }
200 i = a->top;
201 ap = a->d;
202 j = i - (ap[i - 1] == 1);
203 if (a != r) {
204 if (!bn_wexpand(r, j)) {
205 return 0;
206 }
207 r->neg = a->neg;
208 }
209 rp = r->d;
210 t = ap[--i];
211 c = (t & 1) ? BN_TBIT : 0;
212 if (t >>= 1) {
213 rp[i] = t;
214 }
215 while (i > 0) {
216 t = ap[--i];
217 rp[i] = ((t >> 1) & BN_MASK2) | c;
218 c = (t & 1) ? BN_TBIT : 0;
219 }
220 r->top = j;
221
222 if (r->top == 0) {
223 r->neg = 0;
224 }
225
226 return 1;
227 }
228
BN_set_bit(BIGNUM * a,int n)229 int BN_set_bit(BIGNUM *a, int n) {
230 int i, j, k;
231
232 if (n < 0) {
233 return 0;
234 }
235
236 i = n / BN_BITS2;
237 j = n % BN_BITS2;
238 if (a->top <= i) {
239 if (!bn_wexpand(a, i + 1)) {
240 return 0;
241 }
242 for (k = a->top; k < i + 1; k++) {
243 a->d[k] = 0;
244 }
245 a->top = i + 1;
246 }
247
248 a->d[i] |= (((BN_ULONG)1) << j);
249
250 return 1;
251 }
252
BN_clear_bit(BIGNUM * a,int n)253 int BN_clear_bit(BIGNUM *a, int n) {
254 int i, j;
255
256 if (n < 0) {
257 return 0;
258 }
259
260 i = n / BN_BITS2;
261 j = n % BN_BITS2;
262 if (a->top <= i) {
263 return 0;
264 }
265
266 a->d[i] &= (~(((BN_ULONG)1) << j));
267 bn_correct_top(a);
268 return 1;
269 }
270
BN_is_bit_set(const BIGNUM * a,int n)271 int BN_is_bit_set(const BIGNUM *a, int n) {
272 int i, j;
273
274 if (n < 0) {
275 return 0;
276 }
277 i = n / BN_BITS2;
278 j = n % BN_BITS2;
279 if (a->top <= i) {
280 return 0;
281 }
282
283 return (a->d[i]>>j)&1;
284 }
285
BN_mask_bits(BIGNUM * a,int n)286 int BN_mask_bits(BIGNUM *a, int n) {
287 int b, w;
288
289 if (n < 0) {
290 return 0;
291 }
292
293 w = n / BN_BITS2;
294 b = n % BN_BITS2;
295 if (w >= a->top) {
296 return 0;
297 }
298 if (b == 0) {
299 a->top = w;
300 } else {
301 a->top = w + 1;
302 a->d[w] &= ~(BN_MASK2 << b);
303 }
304
305 bn_correct_top(a);
306 return 1;
307 }
308