bn_print.c revision 331638 
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    for (i = a->top - 1; i >= 0; i--) {
86        for (j = BN_BITS2 - 8; j >= 0; j -= 8) {
87            /* strip leading zeros */
88            v = ((int)(a->d[i] >> (long)j)) & 0xff;
89            if (z || (v != 0)) {
90                *(p++) = Hex[v >> 4];
91                *(p++) = Hex[v & 0x0f];
92                z = 1;
93            }
94        }
95    }
96    *p = '\0';
97 err:
98    return (buf);
99}
100
101/* Must 'OPENSSL_free' the returned data */
102char *BN_bn2dec(const BIGNUM *a)
103{
104    int i = 0, num, ok = 0;
105    char *buf = NULL;
106    char *p;
107    BIGNUM *t = NULL;
108    BN_ULONG *bn_data = NULL, *lp;
109    int bn_data_num;
110
111    /*-
112     * get an upper bound for the length of the decimal integer
113     * num <= (BN_num_bits(a) + 1) * log(2)
114     *     <= 3 * BN_num_bits(a) * 0.1001 + log(2) + 1     (rounding error)
115     *     <= BN_num_bits(a)/10 + BN_num_bits/1000 + 1 + 1
116     */
117    i = BN_num_bits(a) * 3;
118    num = (i / 10 + i / 1000 + 1) + 1;
119    bn_data_num = num / BN_DEC_NUM + 1;
120    bn_data = OPENSSL_malloc(bn_data_num * sizeof(BN_ULONG));
121    buf = OPENSSL_malloc(num + 3);
122    if ((buf == NULL) || (bn_data == NULL)) {
123        BNerr(BN_F_BN_BN2DEC, ERR_R_MALLOC_FAILURE);
124        goto err;
125    }
126    if ((t = BN_dup(a)) == NULL)
127        goto err;
128
129#define BUF_REMAIN (num+3 - (size_t)(p - buf))
130    p = buf;
131    lp = bn_data;
132    if (BN_is_zero(t)) {
133        *(p++) = '0';
134        *(p++) = '\0';
135    } else {
136        if (BN_is_negative(t))
137            *p++ = '-';
138
139        while (!BN_is_zero(t)) {
140            if (lp - bn_data >= bn_data_num)
141                goto err;
142            *lp = BN_div_word(t, BN_DEC_CONV);
143            if (*lp == (BN_ULONG)-1)
144                goto err;
145            lp++;
146        }
147        lp--;
148        /*
149         * We now have a series of blocks, BN_DEC_NUM chars in length, where
150         * the last one needs truncation. The blocks need to be reversed in
151         * order.
152         */
153        BIO_snprintf(p, BUF_REMAIN, BN_DEC_FMT1, *lp);
154        while (*p)
155            p++;
156        while (lp != bn_data) {
157            lp--;
158            BIO_snprintf(p, BUF_REMAIN, BN_DEC_FMT2, *lp);
159            while (*p)
160                p++;
161        }
162    }
163    ok = 1;
164 err:
165    if (bn_data != NULL)
166        OPENSSL_free(bn_data);
167    if (t != NULL)
168        BN_free(t);
169    if (!ok && buf) {
170        OPENSSL_free(buf);
171        buf = NULL;
172    }
173
174    return (buf);
175}
176
177int BN_hex2bn(BIGNUM **bn, const char *a)
178{
179    BIGNUM *ret = NULL;
180    BN_ULONG l = 0;
181    int neg = 0, h, m, i, j, k, c;
182    int num;
183
184    if ((a == NULL) || (*a == '\0'))
185        return (0);
186
187    if (*a == '-') {
188        neg = 1;
189        a++;
190    }
191
192    for (i = 0; i <= (INT_MAX/4) && isxdigit((unsigned char)a[i]); i++)
193        continue;
194
195    if (i > INT_MAX/4)
196        goto err;
197
198    num = i + neg;
199    if (bn == NULL)
200        return (num);
201
202    /* a is the start of the hex digits, and it is 'i' long */
203    if (*bn == NULL) {
204        if ((ret = BN_new()) == NULL)
205            return (0);
206    } else {
207        ret = *bn;
208        BN_zero(ret);
209    }
210
211    /* i is the number of hex digits */
212    if (bn_expand(ret, i * 4) == NULL)
213        goto err;
214
215    j = i;                      /* least significant 'hex' */
216    m = 0;
217    h = 0;
218    while (j > 0) {
219        m = ((BN_BYTES * 2) <= j) ? (BN_BYTES * 2) : j;
220        l = 0;
221        for (;;) {
222            c = a[j - m];
223            if ((c >= '0') && (c <= '9'))
224                k = c - '0';
225            else if ((c >= 'a') && (c <= 'f'))
226                k = c - 'a' + 10;
227            else if ((c >= 'A') && (c <= 'F'))
228                k = c - 'A' + 10;
229            else
230                k = 0;          /* paranoia */
231            l = (l << 4) | k;
232
233            if (--m <= 0) {
234                ret->d[h++] = l;
235                break;
236            }
237        }
238        j -= (BN_BYTES * 2);
239    }
240    ret->top = h;
241    bn_correct_top(ret);
242
243    *bn = ret;
244    bn_check_top(ret);
245    /* Don't set the negative flag if it's zero. */
246    if (ret->top != 0)
247        ret->neg = neg;
248    return (num);
249 err:
250    if (*bn == NULL)
251        BN_free(ret);
252    return (0);
253}
254
255int BN_dec2bn(BIGNUM **bn, const char *a)
256{
257    BIGNUM *ret = NULL;
258    BN_ULONG l = 0;
259    int neg = 0, i, j;
260    int num;
261
262    if ((a == NULL) || (*a == '\0'))
263        return (0);
264    if (*a == '-') {
265        neg = 1;
266        a++;
267    }
268
269    for (i = 0; i <= (INT_MAX/4) && isdigit((unsigned char)a[i]); i++)
270        continue;
271
272    if (i > INT_MAX/4)
273        goto err;
274
275    num = i + neg;
276    if (bn == NULL)
277        return (num);
278
279    /*
280     * a is the start of the digits, and it is 'i' long. We chop it into
281     * BN_DEC_NUM digits at a time
282     */
283    if (*bn == NULL) {
284        if ((ret = BN_new()) == NULL)
285            return (0);
286    } else {
287        ret = *bn;
288        BN_zero(ret);
289    }
290
291    /* i is the number of digits, a bit of an over expand */
292    if (bn_expand(ret, i * 4) == NULL)
293        goto err;
294
295    j = BN_DEC_NUM - (i % BN_DEC_NUM);
296    if (j == BN_DEC_NUM)
297        j = 0;
298    l = 0;
299    while (--i >= 0) {
300        l *= 10;
301        l += *a - '0';
302        a++;
303        if (++j == BN_DEC_NUM) {
304            BN_mul_word(ret, BN_DEC_CONV);
305            BN_add_word(ret, l);
306            l = 0;
307            j = 0;
308        }
309    }
310
311    bn_correct_top(ret);
312    *bn = ret;
313    bn_check_top(ret);
314    /* Don't set the negative flag if it's zero. */
315    if (ret->top != 0)
316        ret->neg = neg;
317    return (num);
318 err:
319    if (*bn == NULL)
320        BN_free(ret);
321    return (0);
322}
323
324int BN_asc2bn(BIGNUM **bn, const char *a)
325{
326    const char *p = a;
327
328    if (*p == '-')
329        p++;
330
331    if (p[0] == '0' && (p[1] == 'X' || p[1] == 'x')) {
332        if (!BN_hex2bn(bn, p + 2))
333            return 0;
334    } else {
335        if (!BN_dec2bn(bn, p))
336            return 0;
337    }
338    /* Don't set the negative flag if it's zero. */
339    if (*a == '-' && (*bn)->top != 0)
340        (*bn)->neg = 1;
341    return 1;
342}
343
344#ifndef OPENSSL_NO_BIO
345# ifndef OPENSSL_NO_FP_API
346int BN_print_fp(FILE *fp, const BIGNUM *a)
347{
348    BIO *b;
349    int ret;
350
351    if ((b = BIO_new(BIO_s_file())) == NULL)
352        return (0);
353    BIO_set_fp(b, fp, BIO_NOCLOSE);
354    ret = BN_print(b, a);
355    BIO_free(b);
356    return (ret);
357}
358# endif
359
360int BN_print(BIO *bp, const BIGNUM *a)
361{
362    int i, j, v, z = 0;
363    int ret = 0;
364
365    if ((a->neg) && (BIO_write(bp, "-", 1) != 1))
366        goto end;
367    if (BN_is_zero(a) && (BIO_write(bp, "0", 1) != 1))
368        goto end;
369    for (i = a->top - 1; i >= 0; i--) {
370        for (j = BN_BITS2 - 4; j >= 0; j -= 4) {
371            /* strip leading zeros */
372            v = ((int)(a->d[i] >> (long)j)) & 0x0f;
373            if (z || (v != 0)) {
374                if (BIO_write(bp, &(Hex[v]), 1) != 1)
375                    goto end;
376                z = 1;
377            }
378        }
379    }
380    ret = 1;
381 end:
382    return (ret);
383}
384#endif
385
386char *BN_options(void)
387{
388    static int init = 0;
389    static char data[16];
390
391    if (!init) {
392        init++;
393#ifdef BN_LLONG
394        BIO_snprintf(data, sizeof(data), "bn(%d,%d)",
395                     (int)sizeof(BN_ULLONG) * 8, (int)sizeof(BN_ULONG) * 8);
396#else
397        BIO_snprintf(data, sizeof(data), "bn(%d,%d)",
398                     (int)sizeof(BN_ULONG) * 8, (int)sizeof(BN_ULONG) * 8);
399#endif
400    }
401    return (data);
402}
403