1 /* Copyright (C) 1995-1998 Eric Young (eay (at) cryptsoft.com) 2 * All rights reserved. 3 * 4 * This package is an SSL implementation written 5 * by Eric Young (eay (at) cryptsoft.com). 6 * The implementation was written so as to conform with Netscapes SSL. 7 * 8 * This library is free for commercial and non-commercial use as long as 9 * the following conditions are aheared to. The following conditions 10 * apply to all code found in this distribution, be it the RC4, RSA, 11 * lhash, DES, etc., code; not just the SSL code. The SSL documentation 12 * included with this distribution is covered by the same copyright terms 13 * except that the holder is Tim Hudson (tjh (at) cryptsoft.com). 14 * 15 * Copyright remains Eric Young's, and as such any Copyright notices in 16 * the code are not to be removed. 17 * If this package is used in a product, Eric Young should be given attribution 18 * as the author of the parts of the library used. 19 * This can be in the form of a textual message at program startup or 20 * in documentation (online or textual) provided with the package. 21 * 22 * Redistribution and use in source and binary forms, with or without 23 * modification, are permitted provided that the following conditions 24 * are met: 25 * 1. Redistributions of source code must retain the copyright 26 * notice, this list of conditions and the following disclaimer. 27 * 2. Redistributions in binary form must reproduce the above copyright 28 * notice, this list of conditions and the following disclaimer in the 29 * documentation and/or other materials provided with the distribution. 30 * 3. All advertising materials mentioning features or use of this software 31 * must display the following acknowledgement: 32 * "This product includes cryptographic software written by 33 * Eric Young (eay (at) cryptsoft.com)" 34 * The word 'cryptographic' can be left out if the rouines from the library 35 * being used are not cryptographic related :-). 36 * 4. If you include any Windows specific code (or a derivative thereof) from 37 * the apps directory (application code) you must include an acknowledgement: 38 * "This product includes software written by Tim Hudson (tjh (at) cryptsoft.com)" 39 * 40 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND 41 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 42 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 43 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 44 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 45 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 46 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 47 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 48 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 49 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 50 * SUCH DAMAGE. 51 * 52 * The licence and distribution terms for any publically available version or 53 * derivative of this code cannot be changed. i.e. this code cannot simply be 54 * copied and put under another distribution licence 55 * [including the GNU Public Licence.] */ 56 57 #include <openssl/asn1.h> 58 59 #include <string.h> 60 61 #include <openssl/err.h> 62 #include <openssl/mem.h> 63 64 #include "../internal.h" 65 66 67 ASN1_INTEGER *ASN1_INTEGER_dup(const ASN1_INTEGER *x) 68 { 69 return M_ASN1_INTEGER_dup(x); 70 } 71 72 int ASN1_INTEGER_cmp(const ASN1_INTEGER *x, const ASN1_INTEGER *y) 73 { 74 int neg, ret; 75 /* Compare signs */ 76 neg = x->type & V_ASN1_NEG; 77 if (neg != (y->type & V_ASN1_NEG)) { 78 if (neg) 79 return -1; 80 else 81 return 1; 82 } 83 84 ret = ASN1_STRING_cmp(x, y); 85 86 if (neg) 87 return -ret; 88 else 89 return ret; 90 } 91 92 /* 93 * This converts an ASN1 INTEGER into its content encoding. 94 * The internal representation is an ASN1_STRING whose data is a big endian 95 * representation of the value, ignoring the sign. The sign is determined by 96 * the type: V_ASN1_INTEGER for positive and V_ASN1_NEG_INTEGER for negative. 97 * 98 * Positive integers are no problem: they are almost the same as the DER 99 * encoding, except if the first byte is >= 0x80 we need to add a zero pad. 100 * 101 * Negative integers are a bit trickier... 102 * The DER representation of negative integers is in 2s complement form. 103 * The internal form is converted by complementing each octet and finally 104 * adding one to the result. This can be done less messily with a little trick. 105 * If the internal form has trailing zeroes then they will become FF by the 106 * complement and 0 by the add one (due to carry) so just copy as many trailing 107 * zeros to the destination as there are in the source. The carry will add one 108 * to the last none zero octet: so complement this octet and add one and finally 109 * complement any left over until you get to the start of the string. 110 * 111 * Padding is a little trickier too. If the first bytes is > 0x80 then we pad 112 * with 0xff. However if the first byte is 0x80 and one of the following bytes 113 * is non-zero we pad with 0xff. The reason for this distinction is that 0x80 114 * followed by optional zeros isn't padded. 115 */ 116 117 int i2c_ASN1_INTEGER(ASN1_INTEGER *a, unsigned char **pp) 118 { 119 int pad = 0, ret, i, neg; 120 unsigned char *p, *n, pb = 0; 121 122 if (a == NULL) 123 return (0); 124 neg = a->type & V_ASN1_NEG; 125 if (a->length == 0) 126 ret = 1; 127 else { 128 ret = a->length; 129 i = a->data[0]; 130 if (ret == 1 && i == 0) 131 neg = 0; 132 if (!neg && (i > 127)) { 133 pad = 1; 134 pb = 0; 135 } else if (neg) { 136 if (i > 128) { 137 pad = 1; 138 pb = 0xFF; 139 } else if (i == 128) { 140 /* 141 * Special case: if any other bytes non zero we pad: 142 * otherwise we don't. 143 */ 144 for (i = 1; i < a->length; i++) 145 if (a->data[i]) { 146 pad = 1; 147 pb = 0xFF; 148 break; 149 } 150 } 151 } 152 ret += pad; 153 } 154 if (pp == NULL) 155 return (ret); 156 p = *pp; 157 158 if (pad) 159 *(p++) = pb; 160 if (a->length == 0) 161 *(p++) = 0; 162 else if (!neg) 163 OPENSSL_memcpy(p, a->data, (unsigned int)a->length); 164 else { 165 /* Begin at the end of the encoding */ 166 n = a->data + a->length - 1; 167 p += a->length - 1; 168 i = a->length; 169 /* Copy zeros to destination as long as source is zero */ 170 while (!*n && i > 1) { 171 *(p--) = 0; 172 n--; 173 i--; 174 } 175 /* Complement and increment next octet */ 176 *(p--) = ((*(n--)) ^ 0xff) + 1; 177 i--; 178 /* Complement any octets left */ 179 for (; i > 0; i--) 180 *(p--) = *(n--) ^ 0xff; 181 } 182 183 *pp += ret; 184 return (ret); 185 } 186 187 /* Convert just ASN1 INTEGER content octets to ASN1_INTEGER structure */ 188 189 ASN1_INTEGER *c2i_ASN1_INTEGER(ASN1_INTEGER **a, const unsigned char **pp, 190 long len) 191 { 192 ASN1_INTEGER *ret = NULL; 193 const unsigned char *p, *pend; 194 unsigned char *to, *s; 195 int i; 196 197 if ((a == NULL) || ((*a) == NULL)) { 198 if ((ret = M_ASN1_INTEGER_new()) == NULL) 199 return (NULL); 200 ret->type = V_ASN1_INTEGER; 201 } else 202 ret = (*a); 203 204 p = *pp; 205 pend = p + len; 206 207 /* 208 * We must OPENSSL_malloc stuff, even for 0 bytes otherwise it signifies 209 * a missing NULL parameter. 210 */ 211 s = (unsigned char *)OPENSSL_malloc((int)len + 1); 212 if (s == NULL) { 213 i = ERR_R_MALLOC_FAILURE; 214 goto err; 215 } 216 to = s; 217 if (!len) { 218 /* 219 * Strictly speaking this is an illegal INTEGER but we tolerate it. 220 */ 221 ret->type = V_ASN1_INTEGER; 222 } else if (*p & 0x80) { /* a negative number */ 223 ret->type = V_ASN1_NEG_INTEGER; 224 if ((*p == 0xff) && (len != 1)) { 225 p++; 226 len--; 227 } 228 i = len; 229 p += i - 1; 230 to += i - 1; 231 while ((!*p) && i) { 232 *(to--) = 0; 233 i--; 234 p--; 235 } 236 /* 237 * Special case: if all zeros then the number will be of the form FF 238 * followed by n zero bytes: this corresponds to 1 followed by n zero 239 * bytes. We've already written n zeros so we just append an extra 240 * one and set the first byte to a 1. This is treated separately 241 * because it is the only case where the number of bytes is larger 242 * than len. 243 */ 244 if (!i) { 245 *s = 1; 246 s[len] = 0; 247 len++; 248 } else { 249 *(to--) = (*(p--) ^ 0xff) + 1; 250 i--; 251 for (; i > 0; i--) 252 *(to--) = *(p--) ^ 0xff; 253 } 254 } else { 255 ret->type = V_ASN1_INTEGER; 256 if ((*p == 0) && (len != 1)) { 257 p++; 258 len--; 259 } 260 OPENSSL_memcpy(s, p, (int)len); 261 } 262 263 if (ret->data != NULL) 264 OPENSSL_free(ret->data); 265 ret->data = s; 266 ret->length = (int)len; 267 if (a != NULL) 268 (*a) = ret; 269 *pp = pend; 270 return (ret); 271 err: 272 OPENSSL_PUT_ERROR(ASN1, i); 273 if ((ret != NULL) && ((a == NULL) || (*a != ret))) 274 M_ASN1_INTEGER_free(ret); 275 return (NULL); 276 } 277 278 /* 279 * This is a version of d2i_ASN1_INTEGER that ignores the sign bit of ASN1 280 * integers: some broken software can encode a positive INTEGER with its MSB 281 * set as negative (it doesn't add a padding zero). 282 */ 283 284 ASN1_INTEGER *d2i_ASN1_UINTEGER(ASN1_INTEGER **a, const unsigned char **pp, 285 long length) 286 { 287 ASN1_INTEGER *ret = NULL; 288 const unsigned char *p; 289 unsigned char *s; 290 long len; 291 int inf, tag, xclass; 292 int i; 293 294 if ((a == NULL) || ((*a) == NULL)) { 295 if ((ret = M_ASN1_INTEGER_new()) == NULL) 296 return (NULL); 297 ret->type = V_ASN1_INTEGER; 298 } else 299 ret = (*a); 300 301 p = *pp; 302 inf = ASN1_get_object(&p, &len, &tag, &xclass, length); 303 if (inf & 0x80) { 304 i = ASN1_R_BAD_OBJECT_HEADER; 305 goto err; 306 } 307 308 if (tag != V_ASN1_INTEGER) { 309 i = ASN1_R_EXPECTING_AN_INTEGER; 310 goto err; 311 } 312 313 /* 314 * We must OPENSSL_malloc stuff, even for 0 bytes otherwise it signifies 315 * a missing NULL parameter. 316 */ 317 s = (unsigned char *)OPENSSL_malloc((int)len + 1); 318 if (s == NULL) { 319 i = ERR_R_MALLOC_FAILURE; 320 goto err; 321 } 322 ret->type = V_ASN1_INTEGER; 323 if (len) { 324 if ((*p == 0) && (len != 1)) { 325 p++; 326 len--; 327 } 328 OPENSSL_memcpy(s, p, (int)len); 329 p += len; 330 } 331 332 if (ret->data != NULL) 333 OPENSSL_free(ret->data); 334 ret->data = s; 335 ret->length = (int)len; 336 if (a != NULL) 337 (*a) = ret; 338 *pp = p; 339 return (ret); 340 err: 341 OPENSSL_PUT_ERROR(ASN1, i); 342 if ((ret != NULL) && ((a == NULL) || (*a != ret))) 343 M_ASN1_INTEGER_free(ret); 344 return (NULL); 345 } 346 347 int ASN1_INTEGER_set(ASN1_INTEGER *a, long v) 348 { 349 int j, k; 350 unsigned int i; 351 unsigned char buf[sizeof(long) + 1]; 352 long d; 353 354 a->type = V_ASN1_INTEGER; 355 if (a->length < (int)(sizeof(long) + 1)) { 356 if (a->data != NULL) 357 OPENSSL_free(a->data); 358 if ((a->data = 359 (unsigned char *)OPENSSL_malloc(sizeof(long) + 1)) != NULL) 360 OPENSSL_memset((char *)a->data, 0, sizeof(long) + 1); 361 } 362 if (a->data == NULL) { 363 OPENSSL_PUT_ERROR(ASN1, ERR_R_MALLOC_FAILURE); 364 return (0); 365 } 366 d = v; 367 if (d < 0) { 368 d = -d; 369 a->type = V_ASN1_NEG_INTEGER; 370 } 371 372 for (i = 0; i < sizeof(long); i++) { 373 if (d == 0) 374 break; 375 buf[i] = (int)d & 0xff; 376 d >>= 8; 377 } 378 j = 0; 379 for (k = i - 1; k >= 0; k--) 380 a->data[j++] = buf[k]; 381 a->length = j; 382 return (1); 383 } 384 385 long ASN1_INTEGER_get(const ASN1_INTEGER *a) 386 { 387 int neg = 0, i; 388 long r = 0; 389 390 if (a == NULL) 391 return (0L); 392 i = a->type; 393 if (i == V_ASN1_NEG_INTEGER) 394 neg = 1; 395 else if (i != V_ASN1_INTEGER) 396 return -1; 397 398 if (a->length > (int)sizeof(long)) { 399 /* hmm... a bit ugly, return all ones */ 400 return -1; 401 } 402 if (a->data == NULL) 403 return 0; 404 405 for (i = 0; i < a->length; i++) { 406 r <<= 8; 407 r |= (unsigned char)a->data[i]; 408 } 409 if (neg) 410 r = -r; 411 return (r); 412 } 413 414 ASN1_INTEGER *BN_to_ASN1_INTEGER(const BIGNUM *bn, ASN1_INTEGER *ai) 415 { 416 ASN1_INTEGER *ret; 417 int len, j; 418 419 if (ai == NULL) 420 ret = M_ASN1_INTEGER_new(); 421 else 422 ret = ai; 423 if (ret == NULL) { 424 OPENSSL_PUT_ERROR(ASN1, ASN1_R_NESTED_ASN1_ERROR); 425 goto err; 426 } 427 if (BN_is_negative(bn) && !BN_is_zero(bn)) 428 ret->type = V_ASN1_NEG_INTEGER; 429 else 430 ret->type = V_ASN1_INTEGER; 431 j = BN_num_bits(bn); 432 len = ((j == 0) ? 0 : ((j / 8) + 1)); 433 if (ret->length < len + 4) { 434 unsigned char *new_data = OPENSSL_realloc(ret->data, len + 4); 435 if (!new_data) { 436 OPENSSL_PUT_ERROR(ASN1, ERR_R_MALLOC_FAILURE); 437 goto err; 438 } 439 ret->data = new_data; 440 } 441 ret->length = BN_bn2bin(bn, ret->data); 442 /* Correct zero case */ 443 if (!ret->length) { 444 ret->data[0] = 0; 445 ret->length = 1; 446 } 447 return (ret); 448 err: 449 if (ret != ai) 450 M_ASN1_INTEGER_free(ret); 451 return (NULL); 452 } 453 454 BIGNUM *ASN1_INTEGER_to_BN(const ASN1_INTEGER *ai, BIGNUM *bn) 455 { 456 BIGNUM *ret; 457 458 if ((ret = BN_bin2bn(ai->data, ai->length, bn)) == NULL) 459 OPENSSL_PUT_ERROR(ASN1, ASN1_R_BN_LIB); 460 else if (ai->type == V_ASN1_NEG_INTEGER) 461 BN_set_negative(ret, 1); 462 return (ret); 463 } 464
