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