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_lshift, 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) == NULL) {
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 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) == NULL) {
111 return 0;
112 }
113 r->top = a->top;
114 } else {
115 if (bn_wexpand(r, a->top + 1) == NULL) {
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_rshift, 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) == NULL) {
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 return 1;
186 }
187
BN_rshift1(BIGNUM * r,const BIGNUM * a)188 int BN_rshift1(BIGNUM *r, const BIGNUM *a) {
189 BN_ULONG *ap, *rp, t, c;
190 int i, j;
191
192 if (BN_is_zero(a)) {
193 BN_zero(r);
194 return 1;
195 }
196 i = a->top;
197 ap = a->d;
198 j = i - (ap[i - 1] == 1);
199 if (a != r) {
200 if (bn_wexpand(r, j) == NULL) {
201 return 0;
202 }
203 r->neg = a->neg;
204 }
205 rp = r->d;
206 t = ap[--i];
207 c = (t & 1) ? BN_TBIT : 0;
208 if (t >>= 1) {
209 rp[i] = t;
210 }
211 while (i > 0) {
212 t = ap[--i];
213 rp[i] = ((t >> 1) & BN_MASK2) | c;
214 c = (t & 1) ? BN_TBIT : 0;
215 }
216 r->top = j;
217
218 return 1;
219 }
220
BN_set_bit(BIGNUM * a,int n)221 int BN_set_bit(BIGNUM *a, int n) {
222 int i, j, k;
223
224 if (n < 0) {
225 return 0;
226 }
227
228 i = n / BN_BITS2;
229 j = n % BN_BITS2;
230 if (a->top <= i) {
231 if (bn_wexpand(a, i + 1) == NULL) {
232 return 0;
233 }
234 for (k = a->top; k < i + 1; k++) {
235 a->d[k] = 0;
236 }
237 a->top = i + 1;
238 }
239
240 a->d[i] |= (((BN_ULONG)1) << j);
241
242 return 1;
243 }
244
BN_clear_bit(BIGNUM * a,int n)245 int BN_clear_bit(BIGNUM *a, int n) {
246 int i, j;
247
248 if (n < 0) {
249 return 0;
250 }
251
252 i = n / BN_BITS2;
253 j = n % BN_BITS2;
254 if (a->top <= i) {
255 return 0;
256 }
257
258 a->d[i] &= (~(((BN_ULONG)1) << j));
259 bn_correct_top(a);
260 return 1;
261 }
262
BN_is_bit_set(const BIGNUM * a,int n)263 int BN_is_bit_set(const BIGNUM *a, int n) {
264 int i, j;
265
266 if (n < 0) {
267 return 0;
268 }
269 i = n / BN_BITS2;
270 j = n % BN_BITS2;
271 if (a->top <= i) {
272 return 0;
273 }
274
275 return (a->d[i]>>j)&1;
276 }
277
BN_mask_bits(BIGNUM * a,int n)278 int BN_mask_bits(BIGNUM *a, int n) {
279 int b, w;
280
281 if (n < 0) {
282 return 0;
283 }
284
285 w = n / BN_BITS2;
286 b = n % BN_BITS2;
287 if (w >= a->top) {
288 return 0;
289 }
290 if (b == 0) {
291 a->top = w;
292 } else {
293 a->top = w + 1;
294 a->d[w] &= ~(BN_MASK2 << b);
295 }
296
297 bn_correct_top(a);
298 return 1;
299 }
300