bn_print.c revision 306336 
1/* crypto/bn/bn_print.c */
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 <stdio.h>
60#include <ctype.h>
61#include <limits.h>
62#include "cryptlib.h"
63#include <openssl/buffer.h>
64#include "bn_lcl.h"
65
66static const char Hex[] = "0123456789ABCDEF";
67
68/* Must 'OPENSSL_free' the returned data */
69char *BN_bn2hex(const BIGNUM *a)
70{
71    int i, j, v, z = 0;
72    char *buf;
73    char *p;
74
75    if (a->neg && BN_is_zero(a)) {
76        /* "-0" == 3 bytes including NULL terminator */
77        buf = OPENSSL_malloc(3);
78    } else {
79        buf = OPENSSL_malloc(a->top * BN_BYTES * 2 + 2);
80    }
81    if (buf == NULL) {
82        BNerr(BN_F_BN_BN2HEX, ERR_R_MALLOC_FAILURE);
83        goto err;
84    }
85    p = buf;
86    if (a->neg)
87        *(p++) = '-';
88    if (BN_is_zero(a))
89        *(p++) = '0';
90    for (i = a->top - 1; i >= 0; i--) {
91        for (j = BN_BITS2 - 8; j >= 0; j -= 8) {
92            /* strip leading zeros */
93            v = ((int)(a->d[i] >> (long)j)) & 0xff;
94            if (z || (v != 0)) {
95                *(p++) = Hex[v >> 4];
96                *(p++) = Hex[v & 0x0f];
97                z = 1;
98            }
99        }
100    }
101    *p = '\0';
102 err:
103    return (buf);
104}
105
106/* Must 'OPENSSL_free' the returned data */
107char *BN_bn2dec(const BIGNUM *a)
108{
109    int i = 0, num, ok = 0;
110    char *buf = NULL;
111    char *p;
112    BIGNUM *t = NULL;
113    BN_ULONG *bn_data = NULL, *lp;
114    int bn_data_num;
115
116    /*-
117     * get an upper bound for the length of the decimal integer
118     * num <= (BN_num_bits(a) + 1) * log(2)
119     *     <= 3 * BN_num_bits(a) * 0.1001 + log(2) + 1     (rounding error)
120     *     <= BN_num_bits(a)/10 + BN_num_bits/1000 + 1 + 1
121     */
122    i = BN_num_bits(a) * 3;
123    num = (i / 10 + i / 1000 + 1) + 1;
124    bn_data_num = num / BN_DEC_NUM + 1;
125    bn_data = OPENSSL_malloc(bn_data_num * sizeof(BN_ULONG));
126    buf = (char *)OPENSSL_malloc(num + 3);
127    if ((buf == NULL) || (bn_data == NULL)) {
128        BNerr(BN_F_BN_BN2DEC, ERR_R_MALLOC_FAILURE);
129        goto err;
130    }
131    if ((t = BN_dup(a)) == NULL)
132        goto err;
133
134#define BUF_REMAIN (num+3 - (size_t)(p - buf))
135    p = buf;
136    lp = bn_data;
137    if (BN_is_zero(t)) {
138        *(p++) = '0';
139        *(p++) = '\0';
140    } else {
141        if (BN_is_negative(t))
142            *p++ = '-';
143
144        while (!BN_is_zero(t)) {
145            if (lp - bn_data >= bn_data_num)
146                goto err;
147            *lp = BN_div_word(t, BN_DEC_CONV);
148            if (*lp == (BN_ULONG)-1)
149                goto err;
150            lp++;
151        }
152        lp--;
153        /*
154         * We now have a series of blocks, BN_DEC_NUM chars in length, where
155         * the last one needs truncation. The blocks need to be reversed in
156         * order.
157         */
158        BIO_snprintf(p, BUF_REMAIN, BN_DEC_FMT1, *lp);
159        while (*p)
160            p++;
161        while (lp != bn_data) {
162            lp--;
163            BIO_snprintf(p, BUF_REMAIN, BN_DEC_FMT2, *lp);
164            while (*p)
165                p++;
166        }
167    }
168    ok = 1;
169 err:
170    if (bn_data != NULL)
171        OPENSSL_free(bn_data);
172    if (t != NULL)
173        BN_free(t);
174    if (!ok && buf) {
175        OPENSSL_free(buf);
176        buf = NULL;
177    }
178
179    return (buf);
180}
181
182int BN_hex2bn(BIGNUM **bn, const char *a)
183{
184    BIGNUM *ret = NULL;
185    BN_ULONG l = 0;
186    int neg = 0, h, m, i, j, k, c;
187    int num;
188
189    if ((a == NULL) || (*a == '\0'))
190        return (0);
191
192    if (*a == '-') {
193        neg = 1;
194        a++;
195    }
196
197    for (i = 0; i <= (INT_MAX/4) && isxdigit((unsigned char)a[i]); i++)
198        continue;
199
200    if (i > INT_MAX/4)
201        goto err;
202
203    num = i + neg;
204    if (bn == NULL)
205        return (num);
206
207    /* a is the start of the hex digits, and it is 'i' long */
208    if (*bn == NULL) {
209        if ((ret = BN_new()) == NULL)
210            return (0);
211    } else {
212        ret = *bn;
213        BN_zero(ret);
214    }
215
216    /* i is the number of hex digits */
217    if (bn_expand(ret, i * 4) == NULL)
218        goto err;
219
220    j = i;                      /* least significant 'hex' */
221    m = 0;
222    h = 0;
223    while (j > 0) {
224        m = ((BN_BYTES * 2) <= j) ? (BN_BYTES * 2) : j;
225        l = 0;
226        for (;;) {
227            c = a[j - m];
228            if ((c >= '0') && (c <= '9'))
229                k = c - '0';
230            else if ((c >= 'a') && (c <= 'f'))
231                k = c - 'a' + 10;
232            else if ((c >= 'A') && (c <= 'F'))
233                k = c - 'A' + 10;
234            else
235                k = 0;          /* paranoia */
236            l = (l << 4) | k;
237
238            if (--m <= 0) {
239                ret->d[h++] = l;
240                break;
241            }
242        }
243        j -= (BN_BYTES * 2);
244    }
245    ret->top = h;
246    bn_correct_top(ret);
247    ret->neg = neg;
248
249    *bn = ret;
250    bn_check_top(ret);
251    return (num);
252 err:
253    if (*bn == NULL)
254        BN_free(ret);
255    return (0);
256}
257
258int BN_dec2bn(BIGNUM **bn, const char *a)
259{
260    BIGNUM *ret = NULL;
261    BN_ULONG l = 0;
262    int neg = 0, i, j;
263    int num;
264
265    if ((a == NULL) || (*a == '\0'))
266        return (0);
267    if (*a == '-') {
268        neg = 1;
269        a++;
270    }
271
272    for (i = 0; i <= (INT_MAX/4) && isdigit((unsigned char)a[i]); i++)
273        continue;
274
275    if (i > INT_MAX/4)
276        goto err;
277
278    num = i + neg;
279    if (bn == NULL)
280        return (num);
281
282    /*
283     * a is the start of the digits, and it is 'i' long. We chop it into
284     * BN_DEC_NUM digits at a time
285     */
286    if (*bn == NULL) {
287        if ((ret = BN_new()) == NULL)
288            return (0);
289    } else {
290        ret = *bn;
291        BN_zero(ret);
292    }
293
294    /* i is the number of digits, a bit of an over expand */
295    if (bn_expand(ret, i * 4) == NULL)
296        goto err;
297
298    j = BN_DEC_NUM - (i % BN_DEC_NUM);
299    if (j == BN_DEC_NUM)
300        j = 0;
301    l = 0;
302    while (*a) {
303        l *= 10;
304        l += *a - '0';
305        a++;
306        if (++j == BN_DEC_NUM) {
307            BN_mul_word(ret, BN_DEC_CONV);
308            BN_add_word(ret, l);
309            l = 0;
310            j = 0;
311        }
312    }
313    ret->neg = neg;
314
315    bn_correct_top(ret);
316    *bn = ret;
317    bn_check_top(ret);
318    return (num);
319 err:
320    if (*bn == NULL)
321        BN_free(ret);
322    return (0);
323}
324
325#ifndef OPENSSL_NO_BIO
326# ifndef OPENSSL_NO_FP_API
327int BN_print_fp(FILE *fp, const BIGNUM *a)
328{
329    BIO *b;
330    int ret;
331
332    if ((b = BIO_new(BIO_s_file())) == NULL)
333        return (0);
334    BIO_set_fp(b, fp, BIO_NOCLOSE);
335    ret = BN_print(b, a);
336    BIO_free(b);
337    return (ret);
338}
339# endif
340
341int BN_print(BIO *bp, const BIGNUM *a)
342{
343    int i, j, v, z = 0;
344    int ret = 0;
345
346    if ((a->neg) && (BIO_write(bp, "-", 1) != 1))
347        goto end;
348    if (BN_is_zero(a) && (BIO_write(bp, "0", 1) != 1))
349        goto end;
350    for (i = a->top - 1; i >= 0; i--) {
351        for (j = BN_BITS2 - 4; j >= 0; j -= 4) {
352            /* strip leading zeros */
353            v = ((int)(a->d[i] >> (long)j)) & 0x0f;
354            if (z || (v != 0)) {
355                if (BIO_write(bp, &(Hex[v]), 1) != 1)
356                    goto end;
357                z = 1;
358            }
359        }
360    }
361    ret = 1;
362 end:
363    return (ret);
364}
365#endif
366