bn_print.c revision 306195 
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 (BN_is_zero(a))
76        return OPENSSL_strdup("0");
77    buf = OPENSSL_malloc(a->top * BN_BYTES * 2 + 2);
78    if (buf == NULL) {
79        BNerr(BN_F_BN_BN2HEX, ERR_R_MALLOC_FAILURE);
80        goto err;
81    }
82    p = buf;
83    if (a->neg)
84        *(p++) = '-';
85    if (BN_is_zero(a))
86        *(p++) = '0';
87    for (i = a->top - 1; i >= 0; i--) {
88        for (j = BN_BITS2 - 8; j >= 0; j -= 8) {
89            /* strip leading zeros */
90            v = ((int)(a->d[i] >> (long)j)) & 0xff;
91            if (z || (v != 0)) {
92                *(p++) = Hex[v >> 4];
93                *(p++) = Hex[v & 0x0f];
94                z = 1;
95            }
96        }
97    }
98    *p = '\0';
99 err:
100    return (buf);
101}
102
103/* Must 'OPENSSL_free' the returned data */
104char *BN_bn2dec(const BIGNUM *a)
105{
106    int i = 0, num, ok = 0;
107    char *buf = NULL;
108    char *p;
109    BIGNUM *t = NULL;
110    BN_ULONG *bn_data = NULL, *lp;
111    int bn_data_num;
112
113    /*-
114     * get an upper bound for the length of the decimal integer
115     * num <= (BN_num_bits(a) + 1) * log(2)
116     *     <= 3 * BN_num_bits(a) * 0.1001 + log(2) + 1     (rounding error)
117     *     <= BN_num_bits(a)/10 + BN_num_bits/1000 + 1 + 1
118     */
119    i = BN_num_bits(a) * 3;
120    num = (i / 10 + i / 1000 + 1) + 1;
121    bn_data_num = num / BN_DEC_NUM + 1;
122    bn_data = OPENSSL_malloc(bn_data_num * sizeof(BN_ULONG));
123    buf = OPENSSL_malloc(num + 3);
124    if ((buf == NULL) || (bn_data == NULL)) {
125        BNerr(BN_F_BN_BN2DEC, ERR_R_MALLOC_FAILURE);
126        goto err;
127    }
128    if ((t = BN_dup(a)) == NULL)
129        goto err;
130
131#define BUF_REMAIN (num+3 - (size_t)(p - buf))
132    p = buf;
133    lp = bn_data;
134    if (BN_is_zero(t)) {
135        *(p++) = '0';
136        *(p++) = '\0';
137    } else {
138        if (BN_is_negative(t))
139            *p++ = '-';
140
141        while (!BN_is_zero(t)) {
142            if (lp - bn_data >= bn_data_num)
143                goto err;
144            *lp = BN_div_word(t, BN_DEC_CONV);
145            if (*lp == (BN_ULONG)-1)
146                goto err;
147            lp++;
148        }
149        lp--;
150        /*
151         * We now have a series of blocks, BN_DEC_NUM chars in length, where
152         * the last one needs truncation. The blocks need to be reversed in
153         * order.
154         */
155        BIO_snprintf(p, BUF_REMAIN, BN_DEC_FMT1, *lp);
156        while (*p)
157            p++;
158        while (lp != bn_data) {
159            lp--;
160            BIO_snprintf(p, BUF_REMAIN, BN_DEC_FMT2, *lp);
161            while (*p)
162                p++;
163        }
164    }
165    ok = 1;
166 err:
167    if (bn_data != NULL)
168        OPENSSL_free(bn_data);
169    if (t != NULL)
170        BN_free(t);
171    if (!ok && buf) {
172        OPENSSL_free(buf);
173        buf = NULL;
174    }
175
176    return (buf);
177}
178
179int BN_hex2bn(BIGNUM **bn, const char *a)
180{
181    BIGNUM *ret = NULL;
182    BN_ULONG l = 0;
183    int neg = 0, h, m, i, j, k, c;
184    int num;
185
186    if ((a == NULL) || (*a == '\0'))
187        return (0);
188
189    if (*a == '-') {
190        neg = 1;
191        a++;
192    }
193
194    for (i = 0; i <= (INT_MAX/4) && isxdigit((unsigned char)a[i]); i++)
195        continue;
196
197    if (i > INT_MAX/4)
198        goto err;
199
200    num = i + neg;
201    if (bn == NULL)
202        return (num);
203
204    /* a is the start of the hex digits, and it is 'i' long */
205    if (*bn == NULL) {
206        if ((ret = BN_new()) == NULL)
207            return (0);
208    } else {
209        ret = *bn;
210        BN_zero(ret);
211    }
212
213    /* i is the number of hex digits */
214    if (bn_expand(ret, i * 4) == NULL)
215        goto err;
216
217    j = i;                      /* least significant 'hex' */
218    m = 0;
219    h = 0;
220    while (j > 0) {
221        m = ((BN_BYTES * 2) <= j) ? (BN_BYTES * 2) : j;
222        l = 0;
223        for (;;) {
224            c = a[j - m];
225            if ((c >= '0') && (c <= '9'))
226                k = c - '0';
227            else if ((c >= 'a') && (c <= 'f'))
228                k = c - 'a' + 10;
229            else if ((c >= 'A') && (c <= 'F'))
230                k = c - 'A' + 10;
231            else
232                k = 0;          /* paranoia */
233            l = (l << 4) | k;
234
235            if (--m <= 0) {
236                ret->d[h++] = l;
237                break;
238            }
239        }
240        j -= (BN_BYTES * 2);
241    }
242    ret->top = h;
243    bn_correct_top(ret);
244
245    *bn = ret;
246    bn_check_top(ret);
247    /* Don't set the negative flag if it's zero. */
248    if (ret->top != 0)
249        ret->neg = neg;
250    return (num);
251 err:
252    if (*bn == NULL)
253        BN_free(ret);
254    return (0);
255}
256
257int BN_dec2bn(BIGNUM **bn, const char *a)
258{
259    BIGNUM *ret = NULL;
260    BN_ULONG l = 0;
261    int neg = 0, i, j;
262    int num;
263
264    if ((a == NULL) || (*a == '\0'))
265        return (0);
266    if (*a == '-') {
267        neg = 1;
268        a++;
269    }
270
271    for (i = 0; i <= (INT_MAX/4) && isdigit((unsigned char)a[i]); i++)
272        continue;
273
274    if (i > INT_MAX/4)
275        goto err;
276
277    num = i + neg;
278    if (bn == NULL)
279        return (num);
280
281    /*
282     * a is the start of the digits, and it is 'i' long. We chop it into
283     * BN_DEC_NUM digits at a time
284     */
285    if (*bn == NULL) {
286        if ((ret = BN_new()) == NULL)
287            return (0);
288    } else {
289        ret = *bn;
290        BN_zero(ret);
291    }
292
293    /* i is the number of digits, a bit of an over expand */
294    if (bn_expand(ret, i * 4) == NULL)
295        goto err;
296
297    j = BN_DEC_NUM - (i % BN_DEC_NUM);
298    if (j == BN_DEC_NUM)
299        j = 0;
300    l = 0;
301    while (--i >= 0) {
302        l *= 10;
303        l += *a - '0';
304        a++;
305        if (++j == BN_DEC_NUM) {
306            BN_mul_word(ret, BN_DEC_CONV);
307            BN_add_word(ret, l);
308            l = 0;
309            j = 0;
310        }
311    }
312
313    bn_correct_top(ret);
314    *bn = ret;
315    bn_check_top(ret);
316    /* Don't set the negative flag if it's zero. */
317    if (ret->top != 0)
318        ret->neg = neg;
319    return (num);
320 err:
321    if (*bn == NULL)
322        BN_free(ret);
323    return (0);
324}
325
326int BN_asc2bn(BIGNUM **bn, const char *a)
327{
328    const char *p = a;
329
330    if (*p == '-')
331        p++;
332
333    if (p[0] == '0' && (p[1] == 'X' || p[1] == 'x')) {
334        if (!BN_hex2bn(bn, p + 2))
335            return 0;
336    } else {
337        if (!BN_dec2bn(bn, p))
338            return 0;
339    }
340    /* Don't set the negative flag if it's zero. */
341    if (*a == '-' && (*bn)->top != 0)
342        (*bn)->neg = 1;
343    return 1;
344}
345
346#ifndef OPENSSL_NO_BIO
347# ifndef OPENSSL_NO_FP_API
348int BN_print_fp(FILE *fp, const BIGNUM *a)
349{
350    BIO *b;
351    int ret;
352
353    if ((b = BIO_new(BIO_s_file())) == NULL)
354        return (0);
355    BIO_set_fp(b, fp, BIO_NOCLOSE);
356    ret = BN_print(b, a);
357    BIO_free(b);
358    return (ret);
359}
360# endif
361
362int BN_print(BIO *bp, const BIGNUM *a)
363{
364    int i, j, v, z = 0;
365    int ret = 0;
366
367    if ((a->neg) && (BIO_write(bp, "-", 1) != 1))
368        goto end;
369    if (BN_is_zero(a) && (BIO_write(bp, "0", 1) != 1))
370        goto end;
371    for (i = a->top - 1; i >= 0; i--) {
372        for (j = BN_BITS2 - 4; j >= 0; j -= 4) {
373            /* strip leading zeros */
374            v = ((int)(a->d[i] >> (long)j)) & 0x0f;
375            if (z || (v != 0)) {
376                if (BIO_write(bp, &(Hex[v]), 1) != 1)
377                    goto end;
378                z = 1;
379            }
380        }
381    }
382    ret = 1;
383 end:
384    return (ret);
385}
386#endif
387
388char *BN_options(void)
389{
390    static int init = 0;
391    static char data[16];
392
393    if (!init) {
394        init++;
395#ifdef BN_LLONG
396        BIO_snprintf(data, sizeof data, "bn(%d,%d)",
397                     (int)sizeof(BN_ULLONG) * 8, (int)sizeof(BN_ULONG) * 8);
398#else
399        BIO_snprintf(data, sizeof data, "bn(%d,%d)",
400                     (int)sizeof(BN_ULONG) * 8, (int)sizeof(BN_ULONG) * 8);
401#endif
402    }
403    return (data);
404}
405