lib/libcrypto/bn/bn_print.c

   1 /* $OpenBSD: bn_print.c,v 1.31 2017/01/29 17:49:22 beck 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 *
  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 *
 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
 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
 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
 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
 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
 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 *
 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 }