bn_print.c revision 306230 
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        i = 0;
145        while (!BN_is_zero(t)) {
146            *lp = BN_div_word(t, BN_DEC_CONV);
147            if (*lp == (BN_ULONG)-1)
148                goto err;
149            lp++;
150            if (lp - bn_data >= bn_data_num)
151                goto err;
152        }
153        lp--;
154        /*
155         * We now have a series of blocks, BN_DEC_NUM chars in length, where
156         * the last one needs truncation. The blocks need to be reversed in
157         * order.
158         */
159        BIO_snprintf(p, BUF_REMAIN, BN_DEC_FMT1, *lp);
160        while (*p)
161            p++;
162        while (lp != bn_data) {
163            lp--;
164            BIO_snprintf(p, BUF_REMAIN, BN_DEC_FMT2, *lp);
165            while (*p)
166                p++;
167        }
168    }
169    ok = 1;
170 err:
171    if (bn_data != NULL)
172        OPENSSL_free(bn_data);
173    if (t != NULL)
174        BN_free(t);
175    if (!ok && buf) {
176        OPENSSL_free(buf);
177        buf = NULL;
178    }
179
180    return (buf);
181}
182
183int BN_hex2bn(BIGNUM **bn, const char *a)
184{
185    BIGNUM *ret = NULL;
186    BN_ULONG l = 0;
187    int neg = 0, h, m, i, j, k, c;
188    int num;
189
190    if ((a == NULL) || (*a == '\0'))
191        return (0);
192
193    if (*a == '-') {
194        neg = 1;
195        a++;
196    }
197
198    for (i = 0; i <= (INT_MAX/4) && isxdigit((unsigned char)a[i]); i++)
199        continue;
200
201    if (i > INT_MAX/4)
202        goto err;
203
204    num = i + neg;
205    if (bn == NULL)
206        return (num);
207
208    /* a is the start of the hex digits, and it is 'i' long */
209    if (*bn == NULL) {
210        if ((ret = BN_new()) == NULL)
211            return (0);
212    } else {
213        ret = *bn;
214        BN_zero(ret);
215    }
216
217    /* i is the number of hex digits */
218    if (bn_expand(ret, i * 4) == NULL)
219        goto err;
220
221    j = i;                      /* least significant 'hex' */
222    m = 0;
223    h = 0;
224    while (j > 0) {
225        m = ((BN_BYTES * 2) <= j) ? (BN_BYTES * 2) : j;
226        l = 0;
227        for (;;) {
228            c = a[j - m];
229            if ((c >= '0') && (c <= '9'))
230                k = c - '0';
231            else if ((c >= 'a') && (c <= 'f'))
232                k = c - 'a' + 10;
233            else if ((c >= 'A') && (c <= 'F'))
234                k = c - 'A' + 10;
235            else
236                k = 0;          /* paranoia */
237            l = (l << 4) | k;
238
239            if (--m <= 0) {
240                ret->d[h++] = l;
241                break;
242            }
243        }
244        j -= (BN_BYTES * 2);
245    }
246    ret->top = h;
247    bn_correct_top(ret);
248    ret->neg = neg;
249
250    *bn = ret;
251    bn_check_top(ret);
252    return (num);
253 err:
254    if (*bn == NULL)
255        BN_free(ret);
256    return (0);
257}
258
259int BN_dec2bn(BIGNUM **bn, const char *a)
260{
261    BIGNUM *ret = NULL;
262    BN_ULONG l = 0;
263    int neg = 0, i, j;
264    int num;
265
266    if ((a == NULL) || (*a == '\0'))
267        return (0);
268    if (*a == '-') {
269        neg = 1;
270        a++;
271    }
272
273    for (i = 0; i <= (INT_MAX/4) && isdigit((unsigned char)a[i]); i++)
274        continue;
275
276    if (i > INT_MAX/4)
277        goto err;
278
279    num = i + neg;
280    if (bn == NULL)
281        return (num);
282
283    /*
284     * a is the start of the digits, and it is 'i' long. We chop it into
285     * BN_DEC_NUM digits at a time
286     */
287    if (*bn == NULL) {
288        if ((ret = BN_new()) == NULL)
289            return (0);
290    } else {
291        ret = *bn;
292        BN_zero(ret);
293    }
294
295    /* i is the number of digits, a bit of an over expand */
296    if (bn_expand(ret, i * 4) == NULL)
297        goto err;
298
299    j = BN_DEC_NUM - (i % BN_DEC_NUM);
300    if (j == BN_DEC_NUM)
301        j = 0;
302    l = 0;
303    while (*a) {
304        l *= 10;
305        l += *a - '0';
306        a++;
307        if (++j == BN_DEC_NUM) {
308            BN_mul_word(ret, BN_DEC_CONV);
309            BN_add_word(ret, l);
310            l = 0;
311            j = 0;
312        }
313    }
314    ret->neg = neg;
315
316    bn_correct_top(ret);
317    *bn = ret;
318    bn_check_top(ret);
319    return (num);
320 err:
321    if (*bn == NULL)
322        BN_free(ret);
323    return (0);
324}
325
326#ifndef OPENSSL_NO_BIO
327# ifndef OPENSSL_NO_FP_API
328int BN_print_fp(FILE *fp, const BIGNUM *a)
329{
330    BIO *b;
331    int ret;
332
333    if ((b = BIO_new(BIO_s_file())) == NULL)
334        return (0);
335    BIO_set_fp(b, fp, BIO_NOCLOSE);
336    ret = BN_print(b, a);
337    BIO_free(b);
338    return (ret);
339}
340# endif
341
342int BN_print(BIO *bp, const BIGNUM *a)
343{
344    int i, j, v, z = 0;
345    int ret = 0;
346
347    if ((a->neg) && (BIO_write(bp, "-", 1) != 1))
348        goto end;
349    if (BN_is_zero(a) && (BIO_write(bp, "0", 1) != 1))
350        goto end;
351    for (i = a->top - 1; i >= 0; i--) {
352        for (j = BN_BITS2 - 4; j >= 0; j -= 4) {
353            /* strip leading zeros */
354            v = ((int)(a->d[i] >> (long)j)) & 0x0f;
355            if (z || (v != 0)) {
356                if (BIO_write(bp, &(Hex[v]), 1) != 1)
357                    goto end;
358                z = 1;
359            }
360        }
361    }
362    ret = 1;
363 end:
364    return (ret);
365}
366#endif
367