1 /* $OpenBSD: bn_print.c,v 1.32 2021/08/31 11:19:19 tb Exp $ */
2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
3 * All rights reserved.
4 *
5 * This package is an SSL implementation written
6 * by Eric Young (eay@cryptsoft.com).
7 * The implementation was written so as to conform with Netscapes SSL.
8 *
9 * This library is free for commercial and non-commercial use as long as
10 * the following conditions are aheared to. The following conditions
11 * apply to all code found in this distribution, be it the RC4, RSA,
12 * lhash, DES, etc., code; not just the SSL code. The SSL documentation
13 * included with this distribution is covered by the same copyright terms
14 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
15 *
16 * Copyright remains Eric Young's, and as such any Copyright notices in
17 * the code are not to be removed.
18 * If this package is used in a product, Eric Young should be given attribution
19 * as the author of the parts of the library used.
20 * This can be in the form of a textual message at program startup or
21 * in documentation (online or textual) provided with the package.
22 *
23 * Redistribution and use in source and binary forms, with or without
24 * modification, are permitted provided that the following conditions
25 * are met:
26 * 1. Redistributions of source code must retain the copyright
27 * notice, this list of conditions and the following disclaimer.
28 * 2. Redistributions in binary form must reproduce the above copyright
29 * notice, this list of conditions and the following disclaimer in the
30 * documentation and/or other materials provided with the distribution.
31 * 3. All advertising materials mentioning features or use of this software
32 * must display the following acknowledgement:
33 * "This product includes cryptographic software written by
34 * Eric Young (eay@cryptsoft.com)"
35 * The word 'cryptographic' can be left out if the rouines from the library
36 * being used are not cryptographic related :-).
37 * 4. If you include any Windows specific code (or a derivative thereof) from
38 * the apps directory (application code) you must include an acknowledgement:
39 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
40 *
41 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
42 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
43 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
44 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
45 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
46 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
47 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
49 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
50 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
51 * SUCH DAMAGE.
52 *
53 * The licence and distribution terms for any publically available version or
54 * derivative of this code cannot be changed. i.e. this code cannot simply be
55 * copied and put under another distribution licence
56 * [including the GNU Public Licence.]
57 */
58
59 #include <ctype.h>
60 #include <limits.h>
61 #include <stdio.h>
62
63 #include <openssl/opensslconf.h>
64
65 #include <openssl/bio.h>
66 #include <openssl/buffer.h>
67 #include <openssl/err.h>
68
69 #include "bn_lcl.h"
70
71 static const char Hex[]="0123456789ABCDEF";
72
73 /* Must 'free' the returned data */
74 char *
BN_bn2hex(const BIGNUM * a)75 BN_bn2hex(const BIGNUM *a)
76 {
77 int i, j, v, z = 0;
78 char *buf;
79 char *p;
80
81 buf = malloc(BN_is_negative(a) + a->top * BN_BYTES * 2 + 2);
82 if (buf == NULL) {
83 BNerror(ERR_R_MALLOC_FAILURE);
84 goto err;
85 }
86 p = buf;
87 if (BN_is_negative(a))
88 *p++ = '-';
89 if (BN_is_zero(a))
90 *p++ = '0';
91 for (i = a->top - 1; i >=0; i--) {
92 for (j = BN_BITS2 - 8; j >= 0; j -= 8) {
93 /* strip leading zeros */
94 v = ((int)(a->d[i] >> (long)j)) & 0xff;
95 if (z || (v != 0)) {
96 *p++ = Hex[v >> 4];
97 *p++ = Hex[v & 0x0f];
98 z = 1;
99 }
100 }
101 }
102 *p = '\0';
103
104 err:
105 return (buf);
106 }
107
108 /* Must 'free' the returned data */
109 char *
BN_bn2dec(const BIGNUM * a)110 BN_bn2dec(const BIGNUM *a)
111 {
112 int i = 0, num, bn_data_num, ok = 0;
113 char *buf = NULL;
114 char *p;
115 BIGNUM *t = NULL;
116 BN_ULONG *bn_data = NULL, *lp;
117
118 if (BN_is_zero(a)) {
119 buf = malloc(BN_is_negative(a) + 2);
120 if (buf == NULL) {
121 BNerror(ERR_R_MALLOC_FAILURE);
122 goto err;
123 }
124 p = buf;
125 if (BN_is_negative(a))
126 *p++ = '-';
127 *p++ = '0';
128 *p++ = '\0';
129 return (buf);
130 }
131
132 /* get an upper bound for the length of the decimal integer
133 * num <= (BN_num_bits(a) + 1) * log(2)
134 * <= 3 * BN_num_bits(a) * 0.1001 + log(2) + 1 (rounding error)
135 * <= BN_num_bits(a)/10 + BN_num_bits/1000 + 1 + 1
136 */
137 i = BN_num_bits(a) * 3;
138 num = (i / 10 + i / 1000 + 1) + 1;
139 bn_data_num = num / BN_DEC_NUM + 1;
140 bn_data = reallocarray(NULL, bn_data_num, sizeof(BN_ULONG));
141 buf = malloc(num + 3);
142 if ((buf == NULL) || (bn_data == NULL)) {
143 BNerror(ERR_R_MALLOC_FAILURE);
144 goto err;
145 }
146 if ((t = BN_dup(a)) == NULL)
147 goto err;
148
149 #define BUF_REMAIN (num+3 - (size_t)(p - buf))
150 p = buf;
151 lp = bn_data;
152 if (BN_is_negative(t))
153 *p++ = '-';
154
155 while (!BN_is_zero(t)) {
156 if (lp - bn_data >= bn_data_num)
157 goto err;
158 *lp = BN_div_word(t, BN_DEC_CONV);
159 if (*lp == (BN_ULONG)-1)
160 goto err;
161 lp++;
162 }
163 lp--;
164 /* We now have a series of blocks, BN_DEC_NUM chars
165 * in length, where the last one needs truncation.
166 * The blocks need to be reversed in order. */
167 snprintf(p, BUF_REMAIN, BN_DEC_FMT1, *lp);
168 while (*p)
169 p++;
170 while (lp != bn_data) {
171 lp--;
172 snprintf(p, BUF_REMAIN, BN_DEC_FMT2, *lp);
173 while (*p)
174 p++;
175 }
176 ok = 1;
177
178 err:
179 free(bn_data);
180 BN_free(t);
181 if (!ok && buf) {
182 free(buf);
183 buf = NULL;
184 }
185
186 return (buf);
187 }
188
189 int
BN_hex2bn(BIGNUM ** bn,const char * a)190 BN_hex2bn(BIGNUM **bn, const char *a)
191 {
192 BIGNUM *ret = NULL;
193 BN_ULONG l = 0;
194 int neg = 0, h, m, i,j, k, c;
195 int num;
196
197 if ((a == NULL) || (*a == '\0'))
198 return (0);
199
200 if (*a == '-') {
201 neg = 1;
202 a++;
203 }
204
205 for (i = 0; i <= (INT_MAX / 4) && isxdigit((unsigned char)a[i]); i++)
206 ;
207 if (i > INT_MAX / 4)
208 goto err;
209
210 num = i + neg;
211 if (bn == NULL)
212 return (num);
213
214 /* a is the start of the hex digits, and it is 'i' long */
215 if (*bn == NULL) {
216 if ((ret = BN_new()) == NULL)
217 return (0);
218 } else {
219 ret = *bn;
220 BN_zero(ret);
221 }
222
223 /* i is the number of hex digits */
224 if (bn_expand(ret, i * 4) == NULL)
225 goto err;
226
227 j = i; /* least significant 'hex' */
228 m = 0;
229 h = 0;
230 while (j > 0) {
231 m = ((BN_BYTES * 2) <= j) ? (BN_BYTES * 2) : j;
232 l = 0;
233 for (;;) {
234 c = a[j - m];
235 if ((c >= '0') && (c <= '9'))
236 k = c - '0';
237 else if ((c >= 'a') && (c <= 'f'))
238 k = c - 'a' + 10;
239 else if ((c >= 'A') && (c <= 'F'))
240 k = c - 'A' + 10;
241 else
242 k = 0; /* paranoia */
243 l = (l << 4) | k;
244
245 if (--m <= 0) {
246 ret->d[h++] = l;
247 break;
248 }
249 }
250 j -= (BN_BYTES * 2);
251 }
252 ret->top = h;
253 bn_correct_top(ret);
254 ret->neg = neg;
255
256 *bn = ret;
257 bn_check_top(ret);
258 return (num);
259
260 err:
261 if (*bn == NULL)
262 BN_free(ret);
263 return (0);
264 }
265
266 int
BN_dec2bn(BIGNUM ** bn,const char * a)267 BN_dec2bn(BIGNUM **bn, const char *a)
268 {
269 BIGNUM *ret = NULL;
270 BN_ULONG l = 0;
271 int neg = 0, i, j;
272 int num;
273
274 if ((a == NULL) || (*a == '\0'))
275 return (0);
276 if (*a == '-') {
277 neg = 1;
278 a++;
279 }
280
281 for (i = 0; i <= (INT_MAX / 4) && isdigit((unsigned char)a[i]); i++)
282 ;
283 if (i > INT_MAX / 4)
284 goto err;
285
286 num = i + neg;
287 if (bn == NULL)
288 return (num);
289
290 /* a is the start of the digits, and it is 'i' long.
291 * We chop it into BN_DEC_NUM digits at a time */
292 if (*bn == NULL) {
293 if ((ret = BN_new()) == NULL)
294 return (0);
295 } else {
296 ret = *bn;
297 BN_zero(ret);
298 }
299
300 /* i is the number of digits, a bit of an over expand */
301 if (bn_expand(ret, i * 4) == NULL)
302 goto err;
303
304 j = BN_DEC_NUM - (i % BN_DEC_NUM);
305 if (j == BN_DEC_NUM)
306 j = 0;
307 l = 0;
308 while (*a) {
309 l *= 10;
310 l += *a - '0';
311 a++;
312 if (++j == BN_DEC_NUM) {
313 BN_mul_word(ret, BN_DEC_CONV);
314 BN_add_word(ret, l);
315 l = 0;
316 j = 0;
317 }
318 }
319 ret->neg = neg;
320
321 bn_correct_top(ret);
322 *bn = ret;
323 bn_check_top(ret);
324 return (num);
325
326 err:
327 if (*bn == NULL)
328 BN_free(ret);
329 return (0);
330 }
331
332 int
BN_asc2bn(BIGNUM ** bn,const char * a)333 BN_asc2bn(BIGNUM **bn, const char *a)
334 {
335 const char *p = a;
336 if (*p == '-')
337 p++;
338
339 if (p[0] == '0' && (p[1] == 'X' || p[1] == 'x')) {
340 if (!BN_hex2bn(bn, p + 2))
341 return 0;
342 } else {
343 if (!BN_dec2bn(bn, p))
344 return 0;
345 }
346 if (*a == '-')
347 (*bn)->neg = 1;
348 return 1;
349 }
350
351 #ifndef OPENSSL_NO_BIO
352 int
BN_print_fp(FILE * fp,const BIGNUM * a)353 BN_print_fp(FILE *fp, const BIGNUM *a)
354 {
355 BIO *b;
356 int ret;
357
358 if ((b = BIO_new(BIO_s_file())) == NULL)
359 return (0);
360 BIO_set_fp(b, fp, BIO_NOCLOSE);
361 ret = BN_print(b, a);
362 BIO_free(b);
363 return (ret);
364 }
365
366 int
BN_print(BIO * bp,const BIGNUM * a)367 BN_print(BIO *bp, const BIGNUM *a)
368 {
369 int i, j, v, z = 0;
370 int ret = 0;
371
372 if ((a->neg) && (BIO_write(bp, "-", 1) != 1))
373 goto end;
374 if (BN_is_zero(a) && (BIO_write(bp, "0", 1) != 1))
375 goto end;
376 for (i = a->top - 1; i >= 0; i--) {
377 for (j = BN_BITS2 - 4; j >= 0; j -= 4) {
378 /* strip leading zeros */
379 v = ((int)(a->d[i] >> (long)j)) & 0x0f;
380 if (z || (v != 0)) {
381 if (BIO_write(bp, &(Hex[v]), 1) != 1)
382 goto end;
383 z = 1;
384 }
385 }
386 }
387 ret = 1;
388
389 end:
390 return (ret);
391 }
392 #endif
393
394 char *
BN_options(void)395 BN_options(void)
396 {
397 static int init = 0;
398 static char data[16];
399
400 if (!init) {
401 init++;
402 #ifdef BN_LLONG
403 snprintf(data,sizeof data, "bn(%d,%d)",
404 (int)sizeof(BN_ULLONG) * 8, (int)sizeof(BN_ULONG) * 8);
405 #else
406 snprintf(data,sizeof data, "bn(%d,%d)",
407 (int)sizeof(BN_ULONG) * 8, (int)sizeof(BN_ULONG) * 8);
408 #endif
409 }
410 return (data);
411 }
412