a_int.c revision 296341
1/* crypto/asn1/a_int.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 "cryptlib.h" 61#include <openssl/asn1.h> 62#include <openssl/bn.h> 63 64ASN1_INTEGER *ASN1_INTEGER_dup(const ASN1_INTEGER *x) 65{ 66 return M_ASN1_INTEGER_dup(x); 67} 68 69int ASN1_INTEGER_cmp(const ASN1_INTEGER *x, const ASN1_INTEGER *y) 70{ 71 int neg, ret; 72 /* Compare signs */ 73 neg = x->type & V_ASN1_NEG; 74 if (neg != (y->type & V_ASN1_NEG)) { 75 if (neg) 76 return -1; 77 else 78 return 1; 79 } 80 81 ret = ASN1_STRING_cmp(x, y); 82 83 if (neg) 84 return -ret; 85 else 86 return ret; 87} 88 89/*- 90 * This converts an ASN1 INTEGER into its content encoding. 91 * The internal representation is an ASN1_STRING whose data is a big endian 92 * representation of the value, ignoring the sign. The sign is determined by 93 * the type: V_ASN1_INTEGER for positive and V_ASN1_NEG_INTEGER for negative. 94 * 95 * Positive integers are no problem: they are almost the same as the DER 96 * encoding, except if the first byte is >= 0x80 we need to add a zero pad. 97 * 98 * Negative integers are a bit trickier... 99 * The DER representation of negative integers is in 2s complement form. 100 * The internal form is converted by complementing each octet and finally 101 * adding one to the result. This can be done less messily with a little trick. 102 * If the internal form has trailing zeroes then they will become FF by the 103 * complement and 0 by the add one (due to carry) so just copy as many trailing 104 * zeros to the destination as there are in the source. The carry will add one 105 * to the last none zero octet: so complement this octet and add one and finally 106 * complement any left over until you get to the start of the string. 107 * 108 * Padding is a little trickier too. If the first bytes is > 0x80 then we pad 109 * with 0xff. However if the first byte is 0x80 and one of the following bytes 110 * is non-zero we pad with 0xff. The reason for this distinction is that 0x80 111 * followed by optional zeros isn't padded. 112 */ 113 114int i2c_ASN1_INTEGER(ASN1_INTEGER *a, unsigned char **pp) 115{ 116 int pad = 0, ret, i, neg; 117 unsigned char *p, *n, pb = 0; 118 119 if (a == NULL) 120 return (0); 121 neg = a->type & V_ASN1_NEG; 122 if (a->length == 0) 123 ret = 1; 124 else { 125 ret = a->length; 126 i = a->data[0]; 127 if (ret == 1 && i == 0) 128 neg = 0; 129 if (!neg && (i > 127)) { 130 pad = 1; 131 pb = 0; 132 } else if (neg) { 133 if (i > 128) { 134 pad = 1; 135 pb = 0xFF; 136 } else if (i == 128) { 137 /* 138 * Special case: if any other bytes non zero we pad: 139 * otherwise we don't. 140 */ 141 for (i = 1; i < a->length; i++) 142 if (a->data[i]) { 143 pad = 1; 144 pb = 0xFF; 145 break; 146 } 147 } 148 } 149 ret += pad; 150 } 151 if (pp == NULL) 152 return (ret); 153 p = *pp; 154 155 if (pad) 156 *(p++) = pb; 157 if (a->length == 0) 158 *(p++) = 0; 159 else if (!neg) 160 memcpy(p, a->data, (unsigned int)a->length); 161 else { 162 /* Begin at the end of the encoding */ 163 n = a->data + a->length - 1; 164 p += a->length - 1; 165 i = a->length; 166 /* Copy zeros to destination as long as source is zero */ 167 while (!*n && i > 1) { 168 *(p--) = 0; 169 n--; 170 i--; 171 } 172 /* Complement and increment next octet */ 173 *(p--) = ((*(n--)) ^ 0xff) + 1; 174 i--; 175 /* Complement any octets left */ 176 for (; i > 0; i--) 177 *(p--) = *(n--) ^ 0xff; 178 } 179 180 *pp += ret; 181 return (ret); 182} 183 184/* Convert just ASN1 INTEGER content octets to ASN1_INTEGER structure */ 185 186ASN1_INTEGER *c2i_ASN1_INTEGER(ASN1_INTEGER **a, const unsigned char **pp, 187 long len) 188{ 189 ASN1_INTEGER *ret = NULL; 190 const unsigned char *p, *pend; 191 unsigned char *to, *s; 192 int i; 193 194 if ((a == NULL) || ((*a) == NULL)) { 195 if ((ret = M_ASN1_INTEGER_new()) == NULL) 196 return (NULL); 197 ret->type = V_ASN1_INTEGER; 198 } else 199 ret = (*a); 200 201 p = *pp; 202 pend = p + len; 203 204 /* 205 * We must OPENSSL_malloc stuff, even for 0 bytes otherwise it signifies 206 * a missing NULL parameter. 207 */ 208 s = (unsigned char *)OPENSSL_malloc((int)len + 1); 209 if (s == NULL) { 210 i = ERR_R_MALLOC_FAILURE; 211 goto err; 212 } 213 to = s; 214 if (!len) { 215 /* 216 * Strictly speaking this is an illegal INTEGER but we tolerate it. 217 */ 218 ret->type = V_ASN1_INTEGER; 219 } else if (*p & 0x80) { /* a negative number */ 220 ret->type = V_ASN1_NEG_INTEGER; 221 if ((*p == 0xff) && (len != 1)) { 222 p++; 223 len--; 224 } 225 i = len; 226 p += i - 1; 227 to += i - 1; 228 while ((!*p) && i) { 229 *(to--) = 0; 230 i--; 231 p--; 232 } 233 /* 234 * Special case: if all zeros then the number will be of the form FF 235 * followed by n zero bytes: this corresponds to 1 followed by n zero 236 * bytes. We've already written n zeros so we just append an extra 237 * one and set the first byte to a 1. This is treated separately 238 * because it is the only case where the number of bytes is larger 239 * than len. 240 */ 241 if (!i) { 242 *s = 1; 243 s[len] = 0; 244 len++; 245 } else { 246 *(to--) = (*(p--) ^ 0xff) + 1; 247 i--; 248 for (; i > 0; i--) 249 *(to--) = *(p--) ^ 0xff; 250 } 251 } else { 252 ret->type = V_ASN1_INTEGER; 253 if ((*p == 0) && (len != 1)) { 254 p++; 255 len--; 256 } 257 memcpy(s, p, (int)len); 258 } 259 260 if (ret->data != NULL) 261 OPENSSL_free(ret->data); 262 ret->data = s; 263 ret->length = (int)len; 264 if (a != NULL) 265 (*a) = ret; 266 *pp = pend; 267 return (ret); 268 err: 269 ASN1err(ASN1_F_C2I_ASN1_INTEGER, i); 270 if ((ret != NULL) && ((a == NULL) || (*a != ret))) 271 M_ASN1_INTEGER_free(ret); 272 return (NULL); 273} 274 275/* 276 * This is a version of d2i_ASN1_INTEGER that ignores the sign bit of ASN1 277 * integers: some broken software can encode a positive INTEGER with its MSB 278 * set as negative (it doesn't add a padding zero). 279 */ 280 281ASN1_INTEGER *d2i_ASN1_UINTEGER(ASN1_INTEGER **a, const unsigned char **pp, 282 long length) 283{ 284 ASN1_INTEGER *ret = NULL; 285 const unsigned char *p; 286 unsigned char *s; 287 long len; 288 int inf, tag, xclass; 289 int i; 290 291 if ((a == NULL) || ((*a) == NULL)) { 292 if ((ret = M_ASN1_INTEGER_new()) == NULL) 293 return (NULL); 294 ret->type = V_ASN1_INTEGER; 295 } else 296 ret = (*a); 297 298 p = *pp; 299 inf = ASN1_get_object(&p, &len, &tag, &xclass, length); 300 if (inf & 0x80) { 301 i = ASN1_R_BAD_OBJECT_HEADER; 302 goto err; 303 } 304 305 if (tag != V_ASN1_INTEGER) { 306 i = ASN1_R_EXPECTING_AN_INTEGER; 307 goto err; 308 } 309 310 /* 311 * We must OPENSSL_malloc stuff, even for 0 bytes otherwise it signifies 312 * a missing NULL parameter. 313 */ 314 s = (unsigned char *)OPENSSL_malloc((int)len + 1); 315 if (s == NULL) { 316 i = ERR_R_MALLOC_FAILURE; 317 goto err; 318 } 319 ret->type = V_ASN1_INTEGER; 320 if (len) { 321 if ((*p == 0) && (len != 1)) { 322 p++; 323 len--; 324 } 325 memcpy(s, p, (int)len); 326 p += len; 327 } 328 329 if (ret->data != NULL) 330 OPENSSL_free(ret->data); 331 ret->data = s; 332 ret->length = (int)len; 333 if (a != NULL) 334 (*a) = ret; 335 *pp = p; 336 return (ret); 337 err: 338 ASN1err(ASN1_F_D2I_ASN1_UINTEGER, i); 339 if ((ret != NULL) && ((a == NULL) || (*a != ret))) 340 M_ASN1_INTEGER_free(ret); 341 return (NULL); 342} 343 344int ASN1_INTEGER_set(ASN1_INTEGER *a, long v) 345{ 346 int j, k; 347 unsigned int i; 348 unsigned char buf[sizeof(long) + 1]; 349 long d; 350 351 a->type = V_ASN1_INTEGER; 352 if (a->length < (int)(sizeof(long) + 1)) { 353 if (a->data != NULL) 354 OPENSSL_free(a->data); 355 if ((a->data = 356 (unsigned char *)OPENSSL_malloc(sizeof(long) + 1)) != NULL) 357 memset((char *)a->data, 0, sizeof(long) + 1); 358 } 359 if (a->data == NULL) { 360 ASN1err(ASN1_F_ASN1_INTEGER_SET, ERR_R_MALLOC_FAILURE); 361 return (0); 362 } 363 d = v; 364 if (d < 0) { 365 d = -d; 366 a->type = V_ASN1_NEG_INTEGER; 367 } 368 369 for (i = 0; i < sizeof(long); i++) { 370 if (d == 0) 371 break; 372 buf[i] = (int)d & 0xff; 373 d >>= 8; 374 } 375 j = 0; 376 for (k = i - 1; k >= 0; k--) 377 a->data[j++] = buf[k]; 378 a->length = j; 379 return (1); 380} 381 382long ASN1_INTEGER_get(const ASN1_INTEGER *a) 383{ 384 int neg = 0, i; 385 long r = 0; 386 387 if (a == NULL) 388 return (0L); 389 i = a->type; 390 if (i == V_ASN1_NEG_INTEGER) 391 neg = 1; 392 else if (i != V_ASN1_INTEGER) 393 return -1; 394 395 if (a->length > (int)sizeof(long)) { 396 /* hmm... a bit ugly, return all ones */ 397 return -1; 398 } 399 if (a->data == NULL) 400 return 0; 401 402 for (i = 0; i < a->length; i++) { 403 r <<= 8; 404 r |= (unsigned char)a->data[i]; 405 } 406 if (neg) 407 r = -r; 408 return (r); 409} 410 411ASN1_INTEGER *BN_to_ASN1_INTEGER(const BIGNUM *bn, ASN1_INTEGER *ai) 412{ 413 ASN1_INTEGER *ret; 414 int len, j; 415 416 if (ai == NULL) 417 ret = M_ASN1_INTEGER_new(); 418 else 419 ret = ai; 420 if (ret == NULL) { 421 ASN1err(ASN1_F_BN_TO_ASN1_INTEGER, ERR_R_NESTED_ASN1_ERROR); 422 goto err; 423 } 424 if (BN_is_negative(bn) && !BN_is_zero(bn)) 425 ret->type = V_ASN1_NEG_INTEGER; 426 else 427 ret->type = V_ASN1_INTEGER; 428 j = BN_num_bits(bn); 429 len = ((j == 0) ? 0 : ((j / 8) + 1)); 430 if (ret->length < len + 4) { 431 unsigned char *new_data = OPENSSL_realloc(ret->data, len + 4); 432 if (!new_data) { 433 ASN1err(ASN1_F_BN_TO_ASN1_INTEGER, ERR_R_MALLOC_FAILURE); 434 goto err; 435 } 436 ret->data = new_data; 437 } 438 ret->length = BN_bn2bin(bn, ret->data); 439 /* Correct zero case */ 440 if (!ret->length) { 441 ret->data[0] = 0; 442 ret->length = 1; 443 } 444 return (ret); 445 err: 446 if (ret != ai) 447 M_ASN1_INTEGER_free(ret); 448 return (NULL); 449} 450 451BIGNUM *ASN1_INTEGER_to_BN(const ASN1_INTEGER *ai, BIGNUM *bn) 452{ 453 BIGNUM *ret; 454 455 if ((ret = BN_bin2bn(ai->data, ai->length, bn)) == NULL) 456 ASN1err(ASN1_F_ASN1_INTEGER_TO_BN, ASN1_R_BN_LIB); 457 else if (ai->type == V_ASN1_NEG_INTEGER) 458 BN_set_negative(ret, 1); 459 return (ret); 460} 461 462IMPLEMENT_STACK_OF(ASN1_INTEGER) 463 464IMPLEMENT_ASN1_SET_OF(ASN1_INTEGER) 465