a_int.c revision 280304
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 (!neg && (i > 127)) { 128 pad = 1; 129 pb = 0; 130 } else if (neg) { 131 if (i > 128) { 132 pad = 1; 133 pb = 0xFF; 134 } else if (i == 128) { 135 /* 136 * Special case: if any other bytes non zero we pad: 137 * otherwise we don't. 138 */ 139 for (i = 1; i < a->length; i++) 140 if (a->data[i]) { 141 pad = 1; 142 pb = 0xFF; 143 break; 144 } 145 } 146 } 147 ret += pad; 148 } 149 if (pp == NULL) 150 return (ret); 151 p = *pp; 152 153 if (pad) 154 *(p++) = pb; 155 if (a->length == 0) 156 *(p++) = 0; 157 else if (!neg) 158 memcpy(p, a->data, (unsigned int)a->length); 159 else { 160 /* Begin at the end of the encoding */ 161 n = a->data + a->length - 1; 162 p += a->length - 1; 163 i = a->length; 164 /* Copy zeros to destination as long as source is zero */ 165 while (!*n) { 166 *(p--) = 0; 167 n--; 168 i--; 169 } 170 /* Complement and increment next octet */ 171 *(p--) = ((*(n--)) ^ 0xff) + 1; 172 i--; 173 /* Complement any octets left */ 174 for (; i > 0; i--) 175 *(p--) = *(n--) ^ 0xff; 176 } 177 178 *pp += ret; 179 return (ret); 180} 181 182/* Convert just ASN1 INTEGER content octets to ASN1_INTEGER structure */ 183 184ASN1_INTEGER *c2i_ASN1_INTEGER(ASN1_INTEGER **a, const unsigned char **pp, 185 long len) 186{ 187 ASN1_INTEGER *ret = NULL; 188 const unsigned char *p, *pend; 189 unsigned char *to, *s; 190 int i; 191 192 if ((a == NULL) || ((*a) == NULL)) { 193 if ((ret = M_ASN1_INTEGER_new()) == NULL) 194 return (NULL); 195 ret->type = V_ASN1_INTEGER; 196 } else 197 ret = (*a); 198 199 p = *pp; 200 pend = p + len; 201 202 /* 203 * We must OPENSSL_malloc stuff, even for 0 bytes otherwise it signifies 204 * a missing NULL parameter. 205 */ 206 s = (unsigned char *)OPENSSL_malloc((int)len + 1); 207 if (s == NULL) { 208 i = ERR_R_MALLOC_FAILURE; 209 goto err; 210 } 211 to = s; 212 if (!len) { 213 /* 214 * Strictly speaking this is an illegal INTEGER but we tolerate it. 215 */ 216 ret->type = V_ASN1_INTEGER; 217 } else if (*p & 0x80) { /* a negative number */ 218 ret->type = V_ASN1_NEG_INTEGER; 219 if ((*p == 0xff) && (len != 1)) { 220 p++; 221 len--; 222 } 223 i = len; 224 p += i - 1; 225 to += i - 1; 226 while ((!*p) && i) { 227 *(to--) = 0; 228 i--; 229 p--; 230 } 231 /* 232 * Special case: if all zeros then the number will be of the form FF 233 * followed by n zero bytes: this corresponds to 1 followed by n zero 234 * bytes. We've already written n zeros so we just append an extra 235 * one and set the first byte to a 1. This is treated separately 236 * because it is the only case where the number of bytes is larger 237 * than len. 238 */ 239 if (!i) { 240 *s = 1; 241 s[len] = 0; 242 len++; 243 } else { 244 *(to--) = (*(p--) ^ 0xff) + 1; 245 i--; 246 for (; i > 0; i--) 247 *(to--) = *(p--) ^ 0xff; 248 } 249 } else { 250 ret->type = V_ASN1_INTEGER; 251 if ((*p == 0) && (len != 1)) { 252 p++; 253 len--; 254 } 255 memcpy(s, p, (int)len); 256 } 257 258 if (ret->data != NULL) 259 OPENSSL_free(ret->data); 260 ret->data = s; 261 ret->length = (int)len; 262 if (a != NULL) 263 (*a) = ret; 264 *pp = pend; 265 return (ret); 266 err: 267 ASN1err(ASN1_F_C2I_ASN1_INTEGER, i); 268 if ((ret != NULL) && ((a == NULL) || (*a != ret))) 269 M_ASN1_INTEGER_free(ret); 270 return (NULL); 271} 272 273/* 274 * This is a version of d2i_ASN1_INTEGER that ignores the sign bit of ASN1 275 * integers: some broken software can encode a positive INTEGER with its MSB 276 * set as negative (it doesn't add a padding zero). 277 */ 278 279ASN1_INTEGER *d2i_ASN1_UINTEGER(ASN1_INTEGER **a, const unsigned char **pp, 280 long length) 281{ 282 ASN1_INTEGER *ret = NULL; 283 const unsigned char *p; 284 unsigned char *s; 285 long len; 286 int inf, tag, xclass; 287 int i; 288 289 if ((a == NULL) || ((*a) == NULL)) { 290 if ((ret = M_ASN1_INTEGER_new()) == NULL) 291 return (NULL); 292 ret->type = V_ASN1_INTEGER; 293 } else 294 ret = (*a); 295 296 p = *pp; 297 inf = ASN1_get_object(&p, &len, &tag, &xclass, length); 298 if (inf & 0x80) { 299 i = ASN1_R_BAD_OBJECT_HEADER; 300 goto err; 301 } 302 303 if (tag != V_ASN1_INTEGER) { 304 i = ASN1_R_EXPECTING_AN_INTEGER; 305 goto err; 306 } 307 308 /* 309 * We must OPENSSL_malloc stuff, even for 0 bytes otherwise it signifies 310 * a missing NULL parameter. 311 */ 312 s = (unsigned char *)OPENSSL_malloc((int)len + 1); 313 if (s == NULL) { 314 i = ERR_R_MALLOC_FAILURE; 315 goto err; 316 } 317 ret->type = V_ASN1_INTEGER; 318 if (len) { 319 if ((*p == 0) && (len != 1)) { 320 p++; 321 len--; 322 } 323 memcpy(s, p, (int)len); 324 p += len; 325 } 326 327 if (ret->data != NULL) 328 OPENSSL_free(ret->data); 329 ret->data = s; 330 ret->length = (int)len; 331 if (a != NULL) 332 (*a) = ret; 333 *pp = p; 334 return (ret); 335 err: 336 ASN1err(ASN1_F_D2I_ASN1_UINTEGER, i); 337 if ((ret != NULL) && ((a == NULL) || (*a != ret))) 338 M_ASN1_INTEGER_free(ret); 339 return (NULL); 340} 341 342int ASN1_INTEGER_set(ASN1_INTEGER *a, long v) 343{ 344 int j, k; 345 unsigned int i; 346 unsigned char buf[sizeof(long) + 1]; 347 long d; 348 349 a->type = V_ASN1_INTEGER; 350 if (a->length < (int)(sizeof(long) + 1)) { 351 if (a->data != NULL) 352 OPENSSL_free(a->data); 353 if ((a->data = 354 (unsigned char *)OPENSSL_malloc(sizeof(long) + 1)) != NULL) 355 memset((char *)a->data, 0, sizeof(long) + 1); 356 } 357 if (a->data == NULL) { 358 ASN1err(ASN1_F_ASN1_INTEGER_SET, ERR_R_MALLOC_FAILURE); 359 return (0); 360 } 361 d = v; 362 if (d < 0) { 363 d = -d; 364 a->type = V_ASN1_NEG_INTEGER; 365 } 366 367 for (i = 0; i < sizeof(long); i++) { 368 if (d == 0) 369 break; 370 buf[i] = (int)d & 0xff; 371 d >>= 8; 372 } 373 j = 0; 374 for (k = i - 1; k >= 0; k--) 375 a->data[j++] = buf[k]; 376 a->length = j; 377 return (1); 378} 379 380long ASN1_INTEGER_get(const ASN1_INTEGER *a) 381{ 382 int neg = 0, i; 383 long r = 0; 384 385 if (a == NULL) 386 return (0L); 387 i = a->type; 388 if (i == V_ASN1_NEG_INTEGER) 389 neg = 1; 390 else if (i != V_ASN1_INTEGER) 391 return -1; 392 393 if (a->length > (int)sizeof(long)) { 394 /* hmm... a bit ugly, return all ones */ 395 return -1; 396 } 397 if (a->data == NULL) 398 return 0; 399 400 for (i = 0; i < a->length; i++) { 401 r <<= 8; 402 r |= (unsigned char)a->data[i]; 403 } 404 if (neg) 405 r = -r; 406 return (r); 407} 408 409ASN1_INTEGER *BN_to_ASN1_INTEGER(const BIGNUM *bn, ASN1_INTEGER *ai) 410{ 411 ASN1_INTEGER *ret; 412 int len, j; 413 414 if (ai == NULL) 415 ret = M_ASN1_INTEGER_new(); 416 else 417 ret = ai; 418 if (ret == NULL) { 419 ASN1err(ASN1_F_BN_TO_ASN1_INTEGER, ERR_R_NESTED_ASN1_ERROR); 420 goto err; 421 } 422 if (BN_is_negative(bn)) 423 ret->type = V_ASN1_NEG_INTEGER; 424 else 425 ret->type = V_ASN1_INTEGER; 426 j = BN_num_bits(bn); 427 len = ((j == 0) ? 0 : ((j / 8) + 1)); 428 if (ret->length < len + 4) { 429 unsigned char *new_data = OPENSSL_realloc(ret->data, len + 4); 430 if (!new_data) { 431 ASN1err(ASN1_F_BN_TO_ASN1_INTEGER, ERR_R_MALLOC_FAILURE); 432 goto err; 433 } 434 ret->data = new_data; 435 } 436 ret->length = BN_bn2bin(bn, ret->data); 437 /* Correct zero case */ 438 if (!ret->length) { 439 ret->data[0] = 0; 440 ret->length = 1; 441 } 442 return (ret); 443 err: 444 if (ret != ai) 445 M_ASN1_INTEGER_free(ret); 446 return (NULL); 447} 448 449BIGNUM *ASN1_INTEGER_to_BN(const ASN1_INTEGER *ai, BIGNUM *bn) 450{ 451 BIGNUM *ret; 452 453 if ((ret = BN_bin2bn(ai->data, ai->length, bn)) == NULL) 454 ASN1err(ASN1_F_ASN1_INTEGER_TO_BN, ASN1_R_BN_LIB); 455 else if (ai->type == V_ASN1_NEG_INTEGER) 456 BN_set_negative(ret, 1); 457 return (ret); 458} 459 460IMPLEMENT_STACK_OF(ASN1_INTEGER) 461 462IMPLEMENT_ASN1_SET_OF(ASN1_INTEGER) 463