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{ return M_ASN1_INTEGER_dup(x);} 66 67int ASN1_INTEGER_cmp(const ASN1_INTEGER *x, const ASN1_INTEGER *y) 68 { 69 int neg, ret; 70 /* Compare signs */ 71 neg = x->type & V_ASN1_NEG; 72 if (neg != (y->type & V_ASN1_NEG)) 73 { 74 if (neg) 75 return -1; 76 else 77 return 1; 78 } 79 80 ret = ASN1_STRING_cmp(x, y); 81 82 if (neg) 83 return -ret; 84 else 85 return ret; 86 } 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) return(0); 120 neg=a->type & V_ASN1_NEG; 121 if (a->length == 0) 122 ret=1; 123 else 124 { 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++) if(a->data[i]) { 140 pad=1; 141 pb=0xFF; 142 break; 143 } 144 } 145 } 146 ret+=pad; 147 } 148 if (pp == NULL) return(ret); 149 p= *pp; 150 151 if (pad) *(p++)=pb; 152 if (a->length == 0) *(p++)=0; 153 else if (!neg) memcpy(p,a->data,(unsigned int)a->length); 154 else { 155 /* Begin at the end of the encoding */ 156 n=a->data + a->length - 1; 157 p += a->length - 1; 158 i = a->length; 159 /* Copy zeros to destination as long as source is zero */ 160 while(!*n) { 161 *(p--) = 0; 162 n--; 163 i--; 164 } 165 /* Complement and increment next octet */ 166 *(p--) = ((*(n--)) ^ 0xff) + 1; 167 i--; 168 /* Complement any octets left */ 169 for(;i > 0; i--) *(p--) = *(n--) ^ 0xff; 170 } 171 172 *pp+=ret; 173 return(ret); 174 } 175 176/* Convert just ASN1 INTEGER content octets to ASN1_INTEGER structure */ 177 178ASN1_INTEGER *c2i_ASN1_INTEGER(ASN1_INTEGER **a, const unsigned char **pp, 179 long len) 180 { 181 ASN1_INTEGER *ret=NULL; 182 const unsigned char *p, *pend; 183 unsigned char *to,*s; 184 int i; 185 186 if ((a == NULL) || ((*a) == NULL)) 187 { 188 if ((ret=M_ASN1_INTEGER_new()) == NULL) return(NULL); 189 ret->type=V_ASN1_INTEGER; 190 } 191 else 192 ret=(*a); 193 194 p= *pp; 195 pend = p + len; 196 197 /* We must OPENSSL_malloc stuff, even for 0 bytes otherwise it 198 * signifies a missing NULL parameter. */ 199 s=(unsigned char *)OPENSSL_malloc((int)len+1); 200 if (s == NULL) 201 { 202 i=ERR_R_MALLOC_FAILURE; 203 goto err; 204 } 205 to=s; 206 if(!len) { 207 /* Strictly speaking this is an illegal INTEGER but we 208 * tolerate it. 209 */ 210 ret->type=V_ASN1_INTEGER; 211 } else if (*p & 0x80) /* a negative number */ 212 { 213 ret->type=V_ASN1_NEG_INTEGER; 214 if ((*p == 0xff) && (len != 1)) { 215 p++; 216 len--; 217 } 218 i = len; 219 p += i - 1; 220 to += i - 1; 221 while((!*p) && i) { 222 *(to--) = 0; 223 i--; 224 p--; 225 } 226 /* Special case: if all zeros then the number will be of 227 * the form FF followed by n zero bytes: this corresponds to 228 * 1 followed by n zero bytes. We've already written n zeros 229 * so we just append an extra one and set the first byte to 230 * a 1. This is treated separately because it is the only case 231 * where the number of bytes is larger than len. 232 */ 233 if(!i) { 234 *s = 1; 235 s[len] = 0; 236 len++; 237 } else { 238 *(to--) = (*(p--) ^ 0xff) + 1; 239 i--; 240 for(;i > 0; i--) *(to--) = *(p--) ^ 0xff; 241 } 242 } else { 243 ret->type=V_ASN1_INTEGER; 244 if ((*p == 0) && (len != 1)) 245 { 246 p++; 247 len--; 248 } 249 memcpy(s,p,(int)len); 250 } 251 252 if (ret->data != NULL) OPENSSL_free(ret->data); 253 ret->data=s; 254 ret->length=(int)len; 255 if (a != NULL) (*a)=ret; 256 *pp=pend; 257 return(ret); 258err: 259 ASN1err(ASN1_F_C2I_ASN1_INTEGER,i); 260 if ((ret != NULL) && ((a == NULL) || (*a != ret))) 261 M_ASN1_INTEGER_free(ret); 262 return(NULL); 263 } 264 265 266/* This is a version of d2i_ASN1_INTEGER that ignores the sign bit of 267 * ASN1 integers: some broken software can encode a positive INTEGER 268 * with its MSB set as negative (it doesn't add a padding zero). 269 */ 270 271ASN1_INTEGER *d2i_ASN1_UINTEGER(ASN1_INTEGER **a, const unsigned char **pp, 272 long length) 273 { 274 ASN1_INTEGER *ret=NULL; 275 const unsigned char *p; 276 unsigned char *s; 277 long len; 278 int inf,tag,xclass; 279 int i; 280 281 if ((a == NULL) || ((*a) == NULL)) 282 { 283 if ((ret=M_ASN1_INTEGER_new()) == NULL) return(NULL); 284 ret->type=V_ASN1_INTEGER; 285 } 286 else 287 ret=(*a); 288 289 p= *pp; 290 inf=ASN1_get_object(&p,&len,&tag,&xclass,length); 291 if (inf & 0x80) 292 { 293 i=ASN1_R_BAD_OBJECT_HEADER; 294 goto err; 295 } 296 297 if (tag != V_ASN1_INTEGER) 298 { 299 i=ASN1_R_EXPECTING_AN_INTEGER; 300 goto err; 301 } 302 303 /* We must OPENSSL_malloc stuff, even for 0 bytes otherwise it 304 * signifies a missing NULL parameter. */ 305 s=(unsigned char *)OPENSSL_malloc((int)len+1); 306 if (s == NULL) 307 { 308 i=ERR_R_MALLOC_FAILURE; 309 goto err; 310 } 311 ret->type=V_ASN1_INTEGER; 312 if(len) { 313 if ((*p == 0) && (len != 1)) 314 { 315 p++; 316 len--; 317 } 318 memcpy(s,p,(int)len); 319 p+=len; 320 } 321 322 if (ret->data != NULL) OPENSSL_free(ret->data); 323 ret->data=s; 324 ret->length=(int)len; 325 if (a != NULL) (*a)=ret; 326 *pp=p; 327 return(ret); 328err: 329 ASN1err(ASN1_F_D2I_ASN1_UINTEGER,i); 330 if ((ret != NULL) && ((a == NULL) || (*a != ret))) 331 M_ASN1_INTEGER_free(ret); 332 return(NULL); 333 } 334 335int ASN1_INTEGER_set(ASN1_INTEGER *a, long v) 336 { 337 int j,k; 338 unsigned int i; 339 unsigned char buf[sizeof(long)+1]; 340 long d; 341 342 a->type=V_ASN1_INTEGER; 343 if (a->length < (int)(sizeof(long)+1)) 344 { 345 if (a->data != NULL) 346 OPENSSL_free(a->data); 347 if ((a->data=(unsigned char *)OPENSSL_malloc(sizeof(long)+1)) != NULL) 348 memset((char *)a->data,0,sizeof(long)+1); 349 } 350 if (a->data == NULL) 351 { 352 ASN1err(ASN1_F_ASN1_INTEGER_SET,ERR_R_MALLOC_FAILURE); 353 return(0); 354 } 355 d=v; 356 if (d < 0) 357 { 358 d= -d; 359 a->type=V_ASN1_NEG_INTEGER; 360 } 361 362 for (i=0; i<sizeof(long); i++) 363 { 364 if (d == 0) break; 365 buf[i]=(int)d&0xff; 366 d>>=8; 367 } 368 j=0; 369 for (k=i-1; k >=0; k--) 370 a->data[j++]=buf[k]; 371 a->length=j; 372 return(1); 373 } 374 375long ASN1_INTEGER_get(const ASN1_INTEGER *a) 376 { 377 int neg=0,i; 378 long r=0; 379 380 if (a == NULL) return(0L); 381 i=a->type; 382 if (i == V_ASN1_NEG_INTEGER) 383 neg=1; 384 else if (i != V_ASN1_INTEGER) 385 return -1; 386 387 if (a->length > (int)sizeof(long)) 388 { 389 /* hmm... a bit ugly, return all ones */ 390 return -1; 391 } 392 if (a->data == NULL) 393 return 0; 394 395 for (i=0; i<a->length; i++) 396 { 397 r<<=8; 398 r|=(unsigned char)a->data[i]; 399 } 400 if (neg) r= -r; 401 return(r); 402 } 403 404ASN1_INTEGER *BN_to_ASN1_INTEGER(const BIGNUM *bn, ASN1_INTEGER *ai) 405 { 406 ASN1_INTEGER *ret; 407 int len,j; 408 409 if (ai == NULL) 410 ret=M_ASN1_INTEGER_new(); 411 else 412 ret=ai; 413 if (ret == NULL) 414 { 415 ASN1err(ASN1_F_BN_TO_ASN1_INTEGER,ERR_R_NESTED_ASN1_ERROR); 416 goto err; 417 } 418 if (BN_is_negative(bn)) 419 ret->type = V_ASN1_NEG_INTEGER; 420 else ret->type=V_ASN1_INTEGER; 421 j=BN_num_bits(bn); 422 len=((j == 0)?0:((j/8)+1)); 423 if (ret->length < len+4) 424 { 425 unsigned char *new_data=OPENSSL_realloc(ret->data, len+4); 426 if (!new_data) 427 { 428 ASN1err(ASN1_F_BN_TO_ASN1_INTEGER,ERR_R_MALLOC_FAILURE); 429 goto err; 430 } 431 ret->data=new_data; 432 } 433 ret->length=BN_bn2bin(bn,ret->data); 434 /* Correct zero case */ 435 if(!ret->length) 436 { 437 ret->data[0] = 0; 438 ret->length = 1; 439 } 440 return(ret); 441err: 442 if (ret != ai) M_ASN1_INTEGER_free(ret); 443 return(NULL); 444 } 445 446BIGNUM *ASN1_INTEGER_to_BN(const ASN1_INTEGER *ai, BIGNUM *bn) 447 { 448 BIGNUM *ret; 449 450 if ((ret=BN_bin2bn(ai->data,ai->length,bn)) == NULL) 451 ASN1err(ASN1_F_ASN1_INTEGER_TO_BN,ASN1_R_BN_LIB); 452 else if(ai->type == V_ASN1_NEG_INTEGER) 453 BN_set_negative(ret, 1); 454 return(ret); 455 } 456 457IMPLEMENT_STACK_OF(ASN1_INTEGER) 458IMPLEMENT_ASN1_SET_OF(ASN1_INTEGER) 459