crypto/asn1/tasn_dec.c

   1 /* tasn_dec.c */
   2 /* Written by Dr Stephen N Henson (shenson@bigfoot.com) for the OpenSSL
   3  * project 2000.
   4  */
   5 /* ====================================================================
   6  * Copyright (c) 2000-2005 The OpenSSL Project.  All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  *
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  *
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in
  17  *    the documentation and/or other materials provided with the
  18  *    distribution.
  19  *
  20  * 3. All advertising materials mentioning features or use of this
  21  *    software must display the following acknowledgment:
  22  *    "This product includes software developed by the OpenSSL Project
  23  *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
  24  *
  25  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
  26  *    endorse or promote products derived from this software without
  27  *    prior written permission. For written permission, please contact
  28  *    licensing@OpenSSL.org.
  29  *
  30  * 5. Products derived from this software may not be called "OpenSSL"
  31  *    nor may "OpenSSL" appear in their names without prior written
  32  *    permission of the OpenSSL Project.
  33  *
  34  * 6. Redistributions of any form whatsoever must retain the following
  35  *    acknowledgment:
  36  *    "This product includes software developed by the OpenSSL Project
  37  *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
  38  *
  39  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
  40  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  41  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  42  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
  43  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  44  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  45  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  46  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  47  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  48  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  49  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  50  * OF THE POSSIBILITY OF SUCH DAMAGE.
  51  * ====================================================================
  52  *
  53  * This product includes cryptographic software written by Eric Young
  54  * (eay@cryptsoft.com).  This product includes software written by Tim
  55  * Hudson (tjh@cryptsoft.com).
  56  *
  57  */
  58
  59
  60 #include <stddef.h>
  61 #include <string.h>
  62 #include <openssl/asn1.h>
  63 #include <openssl/asn1t.h>
  64 #include <openssl/objects.h>
  65 #include <openssl/buffer.h>
  66 #include <openssl/err.h>
  67
  68 static int asn1_check_eoc(const unsigned char **in, long len);
  69 static int asn1_find_end(const unsigned char **in, long len, char inf);
  70
  71 static int asn1_collect(BUF_MEM *buf, const unsigned char **in, long len,
  72                                 char inf, int tag, int aclass);
  73
  74 static int collect_data(BUF_MEM *buf, const unsigned char **p, long plen);
  75
  76 static int asn1_check_tlen(long *olen, int *otag, unsigned char *oclass,
  77                                 char *inf, char *cst,
  78                                 const unsigned char **in, long len,
  79                                 int exptag, int expclass, char opt,
  80                                 ASN1_TLC *ctx);
  81
  82 static int asn1_template_ex_d2i(ASN1_VALUE **pval,
  83                                 const unsigned char **in, long len,
  84                                 const ASN1_TEMPLATE *tt, char opt,
  85                                 ASN1_TLC *ctx);
  86 static int asn1_template_noexp_d2i(ASN1_VALUE **val,
  87                                 const unsigned char **in, long len,
  88                                 const ASN1_TEMPLATE *tt, char opt,
  89                                 ASN1_TLC *ctx);
  90 static int asn1_d2i_ex_primitive(ASN1_VALUE **pval,
  91                                 const unsigned char **in, long len,
  92                                 const ASN1_ITEM *it,
  93                                 int tag, int aclass, char opt, ASN1_TLC *ctx);
  94
  95 /* Table to convert tags to bit values, used for MSTRING type */
  96 static const unsigned long tag2bit[32] = {
  97 0,      0,      0,      B_ASN1_BIT_STRING,      /* tags  0 -  3 */
  98 B_ASN1_OCTET_STRING,    0,      0,              B_ASN1_UNKNOWN,/* tags  4- 7 */
  99 B_ASN1_UNKNOWN, B_ASN1_UNKNOWN, B_ASN1_UNKNOWN, B_ASN1_UNKNOWN,/* tags  8-11 */
 100 B_ASN1_UTF8STRING,B_ASN1_UNKNOWN,B_ASN1_UNKNOWN,B_ASN1_UNKNOWN,/* tags 12-15 */
 101 B_ASN1_SEQUENCE,0,B_ASN1_NUMERICSTRING,B_ASN1_PRINTABLESTRING, /* tags 16-19 */
 102 B_ASN1_T61STRING,B_ASN1_VIDEOTEXSTRING,B_ASN1_IA5STRING,       /* tags 20-22 */
 103 B_ASN1_UTCTIME, B_ASN1_GENERALIZEDTIME,                        /* tags 23-24 */
 104 B_ASN1_GRAPHICSTRING,B_ASN1_ISO64STRING,B_ASN1_GENERALSTRING,  /* tags 25-27 */
 105 B_ASN1_UNIVERSALSTRING,B_ASN1_UNKNOWN,B_ASN1_BMPSTRING,B_ASN1_UNKNOWN, /* tags 28-31 */
 106         };
 107
 108 unsigned long ASN1_tag2bit(int tag)
 109         {
 110         if ((tag < 0) || (tag > 30)) return 0;
 111         return tag2bit[tag];
 112         }
 113
 114 /* Macro to initialize and invalidate the cache */
 115
 116 #define asn1_tlc_clear(c)       if (c) (c)->valid = 0
 117 /* Version to avoid compiler warning about 'c' always non-NULL */
 118 #define asn1_tlc_clear_nc(c)    (c)->valid = 0
 119
 120 /* Decode an ASN1 item, this currently behaves just
 121  * like a standard 'd2i' function. 'in' points to
 122  * a buffer to read the data from, in future we will
 123  * have more advanced versions that can input data
 124  * a piece at a time and this will simply be a special
 125  * case.
 126  */
 127
 128 ASN1_VALUE *ASN1_item_d2i(ASN1_VALUE **pval,
 129                           const unsigned char **in, size_t len,
 130                           const ASN1_ITEM *it)
 131         {
 132         ASN1_TLC c;
 133         ASN1_VALUE *ptmpval = NULL;
 134         if (!pval)
 135                 pval = &ptmpval;
 136         asn1_tlc_clear_nc(&c);
 137         if (ASN1_item_ex_d2i(pval, in, len, it, -1, 0, 0, &c) > 0)
 138                 return *pval;
 139         return NULL;
 140         }
 141
 142 int ASN1_template_d2i(ASN1_VALUE **pval,
 143                 const unsigned char **in, long len, const ASN1_TEMPLATE *tt)
 144         {
 145         ASN1_TLC c;
 146         asn1_tlc_clear_nc(&c);
 147         return asn1_template_ex_d2i(pval, in, len, tt, 0, &c);
 148         }
 149
 150
 151 /* Decode an item, taking care of IMPLICIT tagging, if any.
 152  * If 'opt' set and tag mismatch return -1 to handle OPTIONAL
 153  */
 154
 155 int ASN1_item_ex_d2i(ASN1_VALUE **pval, const unsigned char **in, long len,
 156                         const ASN1_ITEM *it,
 157                         int tag, int aclass, char opt, ASN1_TLC *ctx)
 158         {
 159         const ASN1_TEMPLATE *tt, *errtt = NULL;
 160         const ASN1_COMPAT_FUNCS *cf;
 161         const ASN1_EXTERN_FUNCS *ef;
 162         const ASN1_AUX *aux = it->funcs;
 163         ASN1_aux_cb *asn1_cb;
 164         const unsigned char *p = NULL, *q;
 165         unsigned char *wp=NULL; /* BIG FAT WARNING!  BREAKS CONST WHERE USED */
 166         unsigned char imphack = 0, oclass;
 167         char seq_eoc, seq_nolen, cst, isopt;
 168         long tmplen;
 169         int i;
 170         int otag;
 171         int ret = 0;
 172         ASN1_VALUE *pchval, **pchptr, *ptmpval;
 173         if (!pval)
 174                 return 0;
 175         if (aux && aux->asn1_cb)
 176                 asn1_cb = aux->asn1_cb;
 177         else asn1_cb = 0;
 178
 179         switch(it->itype)
 180                 {
 181                 case ASN1_ITYPE_PRIMITIVE:
 182                 if (it->templates)
 183                         {
 184                         /* tagging or OPTIONAL is currently illegal on an item
 185                          * template because the flags can't get passed down.
 186                          * In practice this isn't a problem: we include the
 187                          * relevant flags from the item template in the
 188                          * template itself.
 189                          */
 190                         if ((tag != -1) || opt)
 191                                 {
 192                                 ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
 193                                 ASN1_R_ILLEGAL_OPTIONS_ON_ITEM_TEMPLATE);
 194                                 goto err;
 195                                 }
 196                         return asn1_template_ex_d2i(pval, in, len,
 197                                         it->templates, opt, ctx);
 198                 }
 199                 return asn1_d2i_ex_primitive(pval, in, len, it,
 200                                                 tag, aclass, opt, ctx);
 201                 break;
 202
 203                 case ASN1_ITYPE_MSTRING:
 204                 p = *in;
 205                 /* Just read in tag and class */
 206                 ret = asn1_check_tlen(NULL, &otag, &oclass, NULL, NULL,
 207                                                 &p, len, -1, 0, 1, ctx);
 208                 if (!ret)
 209                         {
 210                         ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
 211                                         ERR_R_NESTED_ASN1_ERROR);
 212                         goto err;
 213                         }
 214
 215                 /* Must be UNIVERSAL class */
 216                 if (oclass != V_ASN1_UNIVERSAL)
 217                         {
 218                         /* If OPTIONAL, assume this is OK */
 219                         if (opt) return -1;
 220                         ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
 221                                         ASN1_R_MSTRING_NOT_UNIVERSAL);
 222                         goto err;
 223                         }
 224                 /* Check tag matches bit map */
 225                 if (!(ASN1_tag2bit(otag) & it->utype))
 226                         {
 227                         /* If OPTIONAL, assume this is OK */
 228                         if (opt)
 229                                 return -1;
 230                         ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
 231                                         ASN1_R_MSTRING_WRONG_TAG);
 232                         goto err;
 233                         }
 234                 return asn1_d2i_ex_primitive(pval, in, len,
 235                                                 it, otag, 0, 0, ctx);
 236
 237                 case ASN1_ITYPE_EXTERN:
 238                 /* Use new style d2i */
 239                 ef = it->funcs;
 240                 return ef->asn1_ex_d2i(pval, in, len,
 241                                                 it, tag, aclass, opt, ctx);
 242
 243                 case ASN1_ITYPE_COMPAT:
 244                 /* we must resort to old style evil hackery */
 245                 cf = it->funcs;
 246
 247                 /* If OPTIONAL see if it is there */
 248                 if (opt)
 249                         {
 250                         int exptag;
 251                         p = *in;
 252                         if (tag == -1)
 253                                 exptag = it->utype;
 254                         else exptag = tag;
 255                         /* Don't care about anything other than presence
 256                          * of expected tag */
 257
 258                         ret = asn1_check_tlen(NULL, NULL, NULL, NULL, NULL,
 259                                         &p, len, exptag, aclass, 1, ctx);
 260                         if (!ret)
 261                                 {
 262                                 ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
 263                                         ERR_R_NESTED_ASN1_ERROR);
 264                                 goto err;
 265                                 }
 266                         if (ret == -1)
 267                                 return -1;
 268                         }
 269
 270                 /* This is the old style evil hack IMPLICIT handling:
 271                  * since the underlying code is expecting a tag and
 272                  * class other than the one present we change the
 273                  * buffer temporarily then change it back afterwards.
 274                  * This doesn't and never did work for tags > 30.
 275                  *
 276                  * Yes this is *horrible* but it is only needed for
 277                  * old style d2i which will hopefully not be around
 278                  * for much longer.
 279                  * FIXME: should copy the buffer then modify it so
 280                  * the input buffer can be const: we should *always*
 281                  * copy because the old style d2i might modify the
 282                  * buffer.
 283                  */
 284
 285                 if (tag != -1)
 286                         {
 287                         wp = *(unsigned char **)in;
 288                         imphack = *wp;
 289                         if (p == NULL)
 290                                 {
 291                                 ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
 292                                         ERR_R_NESTED_ASN1_ERROR);
 293                                 goto err;
 294                                 }
 295                         *wp = (unsigned char)((*p & V_ASN1_CONSTRUCTED)
 296                                                                 | it->utype);
 297                         }
 298
 299                 ptmpval = cf->asn1_d2i(pval, in, len);
 300
 301                 if (tag != -1)
 302                         *wp = imphack;
 303
 304                 if (ptmpval)
 305                         return 1;
 306
 307                 ASN1err(ASN1_F_ASN1_ITEM_EX_D2I, ERR_R_NESTED_ASN1_ERROR);
 308                 goto err;
 309
 310
 311                 case ASN1_ITYPE_CHOICE:
 312                 if (asn1_cb && !asn1_cb(ASN1_OP_D2I_PRE, pval, it, NULL))
 313                                 goto auxerr;
 314
 315                 /* Allocate structure */
 316                 if (!*pval && !ASN1_item_ex_new(pval, it))
 317                         {
 318                         ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
 319                                                 ERR_R_NESTED_ASN1_ERROR);
 320                         goto err;
 321                         }
 322                 /* CHOICE type, try each possibility in turn */
 323                 pchval = NULL;
 324                 p = *in;
 325                 for (i = 0, tt=it->templates; i < it->tcount; i++, tt++)
 326                         {
 327                         pchptr = asn1_get_field_ptr(pval, tt);
 328                         /* We mark field as OPTIONAL so its absence
 329                          * can be recognised.
 330                          */
 331                         ret = asn1_template_ex_d2i(pchptr, &p, len, tt, 1, ctx);
 332                         /* If field not present, try the next one */
 333                         if (ret == -1)
 334                                 continue;
 335                         /* If positive return, read OK, break loop */
 336                         if (ret > 0)
 337                                 break;
 338                         /* Otherwise must be an ASN1 parsing error */
 339                         errtt = tt;
 340                         ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
 341                                                 ERR_R_NESTED_ASN1_ERROR);
 342                         goto err;
 343                         }
 344
 345                 /* Did we fall off the end without reading anything? */
 346                 if (i == it->tcount)
 347                         {
 348                         /* If OPTIONAL, this is OK */
 349                         if (opt)
 350                                 {
 351                                 /* Free and zero it */
 352                                 ASN1_item_ex_free(pval, it);
 353                                 return -1;
 354                                 }
 355                         ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
 356                                         ASN1_R_NO_MATCHING_CHOICE_TYPE);
 357                         goto err;
 358                         }
 359
 360                 asn1_set_choice_selector(pval, i, it);
 361                 *in = p;
 362                 if (asn1_cb && !asn1_cb(ASN1_OP_D2I_POST, pval, it, NULL))
 363                                 goto auxerr;
 364                 return 1;
 365
 366                 case ASN1_ITYPE_NDEF_SEQUENCE:
 367                 case ASN1_ITYPE_SEQUENCE:
 368                 p = *in;
 369                 tmplen = len;
 370
 371                 /* If no IMPLICIT tagging set to SEQUENCE, UNIVERSAL */
 372                 if (tag == -1)
 373                         {
 374                         tag = V_ASN1_SEQUENCE;
 375                         aclass = V_ASN1_UNIVERSAL;
 376                         }
 377                 /* Get SEQUENCE length and update len, p */
 378                 ret = asn1_check_tlen(&len, NULL, NULL, &seq_eoc, &cst,
 379                                         &p, len, tag, aclass, opt, ctx);
 380                 if (!ret)
 381                         {
 382                         ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
 383                                         ERR_R_NESTED_ASN1_ERROR);
 384                         goto err;
 385                         }
 386                 else if (ret == -1)
 387                         return -1;
 388                 if (aux && (aux->flags & ASN1_AFLG_BROKEN))
 389                         {
 390                         len = tmplen - (p - *in);
 391                         seq_nolen = 1;
 392                         }
 393                 /* If indefinite we don't do a length check */
 394                 else seq_nolen = seq_eoc;
 395                 if (!cst)
 396                         {
 397                         ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
 398                                 ASN1_R_SEQUENCE_NOT_CONSTRUCTED);
 399                         goto err;
 400                         }
 401
 402                 if (!*pval && !ASN1_item_ex_new(pval, it))
 403                         {
 404                         ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
 405                                 ERR_R_NESTED_ASN1_ERROR);
 406                         goto err;
 407                         }
 408
 409                 if (asn1_cb && !asn1_cb(ASN1_OP_D2I_PRE, pval, it, NULL))
 410                                 goto auxerr;
 411
 412                 /* Get each field entry */
 413                 for (i = 0, tt = it->templates; i < it->tcount; i++, tt++)
 414                         {
 415                         const ASN1_TEMPLATE *seqtt;
 416                         ASN1_VALUE **pseqval;
 417                         seqtt = asn1_do_adb(pval, tt, 1);
 418                         if (!seqtt)
 419                                 goto err;
 420                         pseqval = asn1_get_field_ptr(pval, seqtt);
 421                         /* Have we ran out of data? */
 422                         if (!len)
 423                                 break;
 424                         q = p;
 425                         if (asn1_check_eoc(&p, len))
 426                                 {
 427                                 if (!seq_eoc)
 428                                         {
 429                                         ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
 430                                                         ASN1_R_UNEXPECTED_EOC);
 431                                         goto err;
 432                                         }
 433                                 len -= p - q;
 434                                 seq_eoc = 0;
 435                                 q = p;
 436                                 break;
 437                                 }
 438                         /* This determines the OPTIONAL flag value. The field
 439                          * cannot be omitted if it is the last of a SEQUENCE
 440                          * and there is still data to be read. This isn't
 441                          * strictly necessary but it increases efficiency in
 442                          * some cases.
 443                          */
 444                         if (i == (it->tcount - 1))
 445                                 isopt = 0;
 446                         else isopt = (char)(seqtt->flags & ASN1_TFLG_OPTIONAL);
 447                         /* attempt to read in field, allowing each to be
 448                          * OPTIONAL */
 449
 450                         ret = asn1_template_ex_d2i(pseqval, &p, len,
 451                                                         seqtt, isopt, ctx);
 452                         if (!ret)
 453                                 {
 454                                 errtt = seqtt;
 455                                 goto err;
 456                                 }
 457                         else if (ret == -1)
 458                                 {
 459                                 /* OPTIONAL component absent.
 460                                  * Free and zero the field.
 461                                  */
 462                                 ASN1_template_free(pseqval, seqtt);
 463                                 continue;
 464                                 }
 465                         /* Update length */
 466                         len -= p - q;
 467                         }
 468
 469                 /* Check for EOC if expecting one */
 470                 if (seq_eoc && !asn1_check_eoc(&p, len))
 471                         {
 472                         ASN1err(ASN1_F_ASN1_ITEM_EX_D2I, ASN1_R_MISSING_EOC);
 473                         goto err;
 474                         }
 475                 /* Check all data read */
 476                 if (!seq_nolen && len)
 477                         {
 478                         ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
 479                                         ASN1_R_SEQUENCE_LENGTH_MISMATCH);
 480                         goto err;
 481                         }
 482
 483                 /* If we get here we've got no more data in the SEQUENCE,
 484                  * however we may not have read all fields so check all
 485                  * remaining are OPTIONAL and clear any that are.
 486                  */
 487                 for (; i < it->tcount; tt++, i++)
 488                         {
 489                         const ASN1_TEMPLATE *seqtt;
 490                         seqtt = asn1_do_adb(pval, tt, 1);
 491                         if (!seqtt)
 492                                 goto err;
 493                         if (seqtt->flags & ASN1_TFLG_OPTIONAL)
 494                                 {
 495                                 ASN1_VALUE **pseqval;
 496                                 pseqval = asn1_get_field_ptr(pval, seqtt);
 497                                 ASN1_template_free(pseqval, seqtt);
 498                                 }
 499                         else
 500                                 {
 501                                 errtt = seqtt;
 502                                 ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
 503                                                         ASN1_R_FIELD_MISSING);
 504                                 goto err;
 505                                 }
 506                         }
 507                 /* Save encoding */
 508                 if (!asn1_enc_save(pval, *in, p - *in, it))
 509                         goto auxerr;
 510                 *in = p;
 511                 if (asn1_cb && !asn1_cb(ASN1_OP_D2I_POST, pval, it, NULL))
 512                                 goto auxerr;
 513                 return 1;
 514
 515                 default:
 516                 return 0;
 517                 }
 518         auxerr:
 519         ASN1err(ASN1_F_ASN1_ITEM_EX_D2I, ASN1_R_AUX_ERROR);
 520         err:
 521         ASN1_item_ex_free(pval, it);
 522         if (errtt)
 523                 ERR_add_error_data(4, "Field=", errtt->field_name,
 524                                         ", Type=", it->sname);
 525         else
 526                 ERR_add_error_data(2, "Type=", it->sname);
 527         return 0;
 528         }
 529
 530 /* Templates are handled with two separate functions.
 531  * One handles any EXPLICIT tag and the other handles the rest.
 532  */
 533
 534 static int asn1_template_ex_d2i(ASN1_VALUE **val,
 535                                 const unsigned char **in, long inlen,
 536                                 const ASN1_TEMPLATE *tt, char opt,
 537                                                         ASN1_TLC *ctx)
 538         {
 539         int flags, aclass;
 540         int ret;
 541         long len;
 542         const unsigned char *p, *q;
 543         char exp_eoc;
 544         if (!val)
 545                 return 0;
 546         flags = tt->flags;
 547         aclass = flags & ASN1_TFLG_TAG_CLASS;
 548
 549         p = *in;
 550
 551         /* Check if EXPLICIT tag expected */
 552         if (flags & ASN1_TFLG_EXPTAG)
 553                 {
 554                 char cst;
 555                 /* Need to work out amount of data available to the inner
 556                  * content and where it starts: so read in EXPLICIT header to
 557                  * get the info.
 558                  */
 559                 ret = asn1_check_tlen(&len, NULL, NULL, &exp_eoc, &cst,
 560                                         &p, inlen, tt->tag, aclass, opt, ctx);
 561                 q = p;
 562                 if (!ret)
 563                         {
 564                         ASN1err(ASN1_F_ASN1_TEMPLATE_EX_D2I,
 565                                         ERR_R_NESTED_ASN1_ERROR);
 566                         return 0;
 567                         }
 568                 else if (ret == -1)
 569                         return -1;
 570                 if (!cst)
 571                         {
 572                         ASN1err(ASN1_F_ASN1_TEMPLATE_EX_D2I,
 573                                         ASN1_R_EXPLICIT_TAG_NOT_CONSTRUCTED);
 574                         return 0;
 575                         }
 576                 /* We've found the field so it can't be OPTIONAL now */
 577                 ret = asn1_template_noexp_d2i(val, &p, len, tt, 0, ctx);
 578                 if (!ret)
 579                         {
 580                         ASN1err(ASN1_F_ASN1_TEMPLATE_EX_D2I,
 581                                         ERR_R_NESTED_ASN1_ERROR);
 582                         return 0;
 583                         }
 584                 /* We read the field in OK so update length */
 585                 len -= p - q;
 586                 if (exp_eoc)
 587                         {
 588                         /* If NDEF we must have an EOC here */
 589                         if (!asn1_check_eoc(&p, len))
 590                                 {
 591                                 ASN1err(ASN1_F_ASN1_TEMPLATE_EX_D2I,
 592                                                 ASN1_R_MISSING_EOC);
 593                                 goto err;
 594                                 }
 595                         }
 596                 else
 597                         {
 598                         /* Otherwise we must hit the EXPLICIT tag end or its
 599                          * an error */
 600                         if (len)
 601                                 {
 602                                 ASN1err(ASN1_F_ASN1_TEMPLATE_EX_D2I,
 603                                         ASN1_R_EXPLICIT_LENGTH_MISMATCH);
 604                                 goto err;
 605                                 }
 606                         }
 607                 }
 608                 else
 609                         return asn1_template_noexp_d2i(val, in, inlen,
 610                                                                 tt, opt, ctx);
 611
 612         *in = p;
 613         return 1;
 614
 615         err:
 616         ASN1_template_free(val, tt);
 617         *val = NULL;
 618         return 0;
 619         }
 620
 621 static int asn1_template_noexp_d2i(ASN1_VALUE **val,
 622                                 const unsigned char **in, long len,
 623                                 const ASN1_TEMPLATE *tt, char opt,
 624                                 ASN1_TLC *ctx)
 625         {
 626         int flags, aclass;
 627         int ret;
 628         const unsigned char *p, *q;
 629         if (!val)
 630                 return 0;
 631         flags = tt->flags;
 632         aclass = flags & ASN1_TFLG_TAG_CLASS;
 633
 634         p = *in;
 635         q = p;
 636
 637         if (flags & ASN1_TFLG_SK_MASK)
 638                 {
 639                 /* SET OF, SEQUENCE OF */
 640                 int sktag, skaclass;
 641                 char sk_eoc;
 642                 /* First work out expected inner tag value */
 643                 if (flags & ASN1_TFLG_IMPTAG)
 644                         {
 645                         sktag = tt->tag;
 646                         skaclass = aclass;
 647                         }
 648                 else
 649                         {
 650                         skaclass = V_ASN1_UNIVERSAL;
 651                         if (flags & ASN1_TFLG_SET_OF)
 652                                 sktag = V_ASN1_SET;
 653                         else
 654                                 sktag = V_ASN1_SEQUENCE;
 655                         }
 656                 /* Get the tag */
 657                 ret = asn1_check_tlen(&len, NULL, NULL, &sk_eoc, NULL,
 658                                         &p, len, sktag, skaclass, opt, ctx);
 659                 if (!ret)
 660                         {
 661                         ASN1err(ASN1_F_ASN1_TEMPLATE_NOEXP_D2I,
 662                                                 ERR_R_NESTED_ASN1_ERROR);
 663                         return 0;
 664                         }
 665                 else if (ret == -1)
 666                         return -1;
 667                 if (!*val)
 668                         *val = (ASN1_VALUE *)sk_new_null();
 669                 else
 670                         {
 671                         /* We've got a valid STACK: free up any items present */
 672                         STACK_OF(ASN1_VALUE) *sktmp
 673                             = (STACK_OF(ASN1_VALUE) *)*val;
 674                         ASN1_VALUE *vtmp;
 675                         while(sk_ASN1_VALUE_num(sktmp) > 0)
 676                                 {
 677                                 vtmp = sk_ASN1_VALUE_pop(sktmp);
 678                                 ASN1_item_ex_free(&vtmp,
 679                                                 ASN1_ITEM_ptr(tt->item));
 680                                 }
 681                         }
 682
 683                 if (!*val)
 684                         {
 685                         ASN1err(ASN1_F_ASN1_TEMPLATE_NOEXP_D2I,
 686                                                 ERR_R_MALLOC_FAILURE);
 687                         goto err;
 688                         }
 689
 690                 /* Read as many items as we can */
 691                 while(len > 0)
 692                         {
 693                         ASN1_VALUE *skfield;
 694                         q = p;
 695                         /* See if EOC found */
 696                         if (asn1_check_eoc(&p, len))
 697                                 {
 698                                 if (!sk_eoc)
 699                                         {
 700                                         ASN1err(ASN1_F_ASN1_TEMPLATE_NOEXP_D2I,
 701                                                         ASN1_R_UNEXPECTED_EOC);
 702                                         goto err;
 703                                         }
 704                                 len -= p - q;
 705                                 sk_eoc = 0;
 706                                 break;
 707                                 }
 708                         skfield = NULL;
 709                         if (!ASN1_item_ex_d2i(&skfield, &p, len,
 710                                                 ASN1_ITEM_ptr(tt->item),
 711                                                 -1, 0, 0, ctx))
 712                                 {
 713                                 ASN1err(ASN1_F_ASN1_TEMPLATE_NOEXP_D2I,
 714                                         ERR_R_NESTED_ASN1_ERROR);
 715                                 goto err;
 716                                 }
 717                         len -= p - q;
 718                         if (!sk_ASN1_VALUE_push((STACK_OF(ASN1_VALUE) *)*val,
 719                                                 skfield))
 720                                 {
 721                                 ASN1err(ASN1_F_ASN1_TEMPLATE_NOEXP_D2I,
 722                                                 ERR_R_MALLOC_FAILURE);
 723                                 goto err;
 724                                 }
 725                         }
 726                 if (sk_eoc)
 727                         {
 728                         ASN1err(ASN1_F_ASN1_TEMPLATE_NOEXP_D2I, ASN1_R_MISSING_EOC);
 729                         goto err;
 730                         }
 731                 }
 732         else if (flags & ASN1_TFLG_IMPTAG)
 733                 {
 734                 /* IMPLICIT tagging */
 735                 ret = ASN1_item_ex_d2i(val, &p, len,
 736                         ASN1_ITEM_ptr(tt->item), tt->tag, aclass, opt, ctx);
 737                 if (!ret)
 738                         {
 739                         ASN1err(ASN1_F_ASN1_TEMPLATE_NOEXP_D2I,
 740                                                 ERR_R_NESTED_ASN1_ERROR);
 741                         goto err;
 742                         }
 743                 else if (ret == -1)
 744                         return -1;
 745                 }
 746         else
 747                 {
 748                 /* Nothing special */
 749                 ret = ASN1_item_ex_d2i(val, &p, len, ASN1_ITEM_ptr(tt->item),
 750                                                         -1, 0, opt, ctx);
 751                 if (!ret)
 752                         {
 753                         ASN1err(ASN1_F_ASN1_TEMPLATE_NOEXP_D2I,
 754                                         ERR_R_NESTED_ASN1_ERROR);
 755                         goto err;
 756                         }
 757                 else if (ret == -1)
 758                         return -1;
 759                 }
 760
 761         *in = p;
 762         return 1;
 763
 764         err:
 765         ASN1_template_free(val, tt);
 766         *val = NULL;
 767         return 0;
 768         }
 769
 770 static int asn1_d2i_ex_primitive(ASN1_VALUE **pval,
 771                                 const unsigned char **in, long inlen,
 772                                 const ASN1_ITEM *it,
 773                                 int tag, int aclass, char opt, ASN1_TLC *ctx)
 774         {
 775         int ret = 0, utype;
 776         long plen;
 777         char cst, inf, free_cont = 0;
 778         const unsigned char *p;
 779         BUF_MEM buf;
 780         const unsigned char *cont = NULL;
 781         long len;
 782         if (!pval)
 783                 {
 784                 ASN1err(ASN1_F_ASN1_D2I_EX_PRIMITIVE, ASN1_R_ILLEGAL_NULL);
 785                 return 0; /* Should never happen */
 786                 }
 787
 788         if (it->itype == ASN1_ITYPE_MSTRING)
 789                 {
 790                 utype = tag;
 791                 tag = -1;
 792                 }
 793         else
 794                 utype = it->utype;
 795
 796         if (utype == V_ASN1_ANY)
 797                 {
 798                 /* If type is ANY need to figure out type from tag */
 799                 unsigned char oclass;
 800                 if (tag >= 0)
 801                         {
 802                         ASN1err(ASN1_F_ASN1_D2I_EX_PRIMITIVE,
 803                                         ASN1_R_ILLEGAL_TAGGED_ANY);
 804                         return 0;
 805                         }
 806                 if (opt)
 807                         {
 808                         ASN1err(ASN1_F_ASN1_D2I_EX_PRIMITIVE,
 809                                         ASN1_R_ILLEGAL_OPTIONAL_ANY);
 810                         return 0;
 811                         }
 812                 p = *in;
 813                 ret = asn1_check_tlen(NULL, &utype, &oclass, NULL, NULL,
 814                                         &p, inlen, -1, 0, 0, ctx);
 815                 if (!ret)
 816                         {
 817                         ASN1err(ASN1_F_ASN1_D2I_EX_PRIMITIVE,
 818                                         ERR_R_NESTED_ASN1_ERROR);
 819                         return 0;
 820                         }
 821                 if (oclass != V_ASN1_UNIVERSAL)
 822                         utype = V_ASN1_OTHER;
 823                 }
 824         if (tag == -1)
 825                 {
 826                 tag = utype;
 827                 aclass = V_ASN1_UNIVERSAL;
 828                 }
 829         p = *in;
 830         /* Check header */
 831         ret = asn1_check_tlen(&plen, NULL, NULL, &inf, &cst,
 832                                 &p, inlen, tag, aclass, opt, ctx);
 833         if (!ret)
 834                 {
 835                 ASN1err(ASN1_F_ASN1_D2I_EX_PRIMITIVE, ERR_R_NESTED_ASN1_ERROR);
 836                 return 0;
 837                 }
 838         else if (ret == -1)
 839                 return -1;
 840         ret = 0;
 841         /* SEQUENCE, SET and "OTHER" are left in encoded form */
 842         if ((utype == V_ASN1_SEQUENCE)
 843                 || (utype == V_ASN1_SET) || (utype == V_ASN1_OTHER))
 844                 {
 845                 /* Clear context cache for type OTHER because the auto clear
 846                  * when we have a exact match wont work
 847                  */
 848                 if (utype == V_ASN1_OTHER)
 849                         {
 850                         asn1_tlc_clear(ctx);
 851                         }
 852                 /* SEQUENCE and SET must be constructed */
 853                 else if (!cst)
 854                         {
 855                         ASN1err(ASN1_F_ASN1_D2I_EX_PRIMITIVE,
 856                                 ASN1_R_TYPE_NOT_CONSTRUCTED);
 857                         return 0;
 858                         }
 859
 860                 cont = *in;
 861                 /* If indefinite length constructed find the real end */
 862                 if (inf)
 863                         {
 864                         if (!asn1_find_end(&p, plen, inf))
 865                                  goto err;
 866                         len = p - cont;
 867                         }
 868                 else
 869                         {
 870                         len = p - cont + plen;
 871                         p += plen;
 872                         buf.data = NULL;
 873                         }
 874                 }
 875         else if (cst)
 876                 {
 877                 buf.length = 0;
 878                 buf.max = 0;
 879                 buf.data = NULL;
 880                 /* Should really check the internal tags are correct but
 881                  * some things may get this wrong. The relevant specs
 882                  * say that constructed string types should be OCTET STRINGs
 883                  * internally irrespective of the type. So instead just check
 884                  * for UNIVERSAL class and ignore the tag.
 885                  */
 886                 if (!asn1_collect(&buf, &p, plen, inf, -1, V_ASN1_UNIVERSAL))
 887                         {
 888                         free_cont = 1;
 889                         goto err;
 890                         }
 891                 len = buf.length;
 892                 /* Append a final null to string */
 893                 if (!BUF_MEM_grow_clean(&buf, len + 1))
 894                         {
 895                         ASN1err(ASN1_F_ASN1_D2I_EX_PRIMITIVE,
 896                                                 ERR_R_MALLOC_FAILURE);
 897                         return 0;
 898                         }
 899                 buf.data[len] = 0;
 900                 cont = (const unsigned char *)buf.data;
 901                 free_cont = 1;
 902                 }
 903         else
 904                 {
 905                 cont = p;
 906                 len = plen;
 907                 p += plen;
 908                 }
 909
 910         /* We now have content length and type: translate into a structure */
 911         if (!asn1_ex_c2i(pval, cont, len, utype, &free_cont, it))
 912                 goto err;
 913
 914         *in = p;
 915         ret = 1;
 916         err:
 917         if (free_cont && buf.data) OPENSSL_free(buf.data);
 918         return ret;
 919         }
 920
 921 /* Translate ASN1 content octets into a structure */
 922
 923 int asn1_ex_c2i(ASN1_VALUE **pval, const unsigned char *cont, int len,
 924                         int utype, char *free_cont, const ASN1_ITEM *it)
 925         {
 926         ASN1_VALUE **opval = NULL;
 927         ASN1_STRING *stmp;
 928         ASN1_TYPE *typ = NULL;
 929         int ret = 0;
 930         const ASN1_PRIMITIVE_FUNCS *pf;
 931         ASN1_INTEGER **tint;
 932         pf = it->funcs;
 933
 934         if (pf && pf->prim_c2i)
 935                 return pf->prim_c2i(pval, cont, len, utype, free_cont, it);
 936         /* If ANY type clear type and set pointer to internal value */
 937         if (it->utype == V_ASN1_ANY)
 938                 {
 939                 if (!*pval)
 940                         {
 941                         typ = ASN1_TYPE_new();
 942                         if (typ == NULL)
 943                                 goto err;
 944                         *pval = (ASN1_VALUE *)typ;
 945                         }
 946                 else
 947                         typ = (ASN1_TYPE *)*pval;
 948
 949                 if (utype != typ->type)
 950                         ASN1_TYPE_set(typ, utype, NULL);
 951                 opval = pval;
 952                 pval = &typ->value.asn1_value;
 953                 }
 954         switch(utype)
 955                 {
 956                 case V_ASN1_OBJECT:
 957                 if (!c2i_ASN1_OBJECT((ASN1_OBJECT **)pval, &cont, len))
 958                         goto err;
 959                 break;
 960
 961                 case V_ASN1_NULL:
 962                 if (len)
 963                         {
 964                         ASN1err(ASN1_F_ASN1_EX_C2I,
 965                                                 ASN1_R_NULL_IS_WRONG_LENGTH);
 966                         goto err;
 967                         }
 968                 *pval = (ASN1_VALUE *)1;
 969                 break;
 970
 971                 case V_ASN1_BOOLEAN:
 972                 if (len != 1)
 973                         {
 974                         ASN1err(ASN1_F_ASN1_EX_C2I,
 975                                                 ASN1_R_BOOLEAN_IS_WRONG_LENGTH);
 976                         goto err;
 977                         }
 978                 else
 979                         {
 980                         ASN1_BOOLEAN *tbool;
 981                         tbool = (ASN1_BOOLEAN *)pval;
 982                         *tbool = *cont;
 983                         }
 984                 break;
 985
 986                 case V_ASN1_BIT_STRING:
 987                 if (!c2i_ASN1_BIT_STRING((ASN1_BIT_STRING **)pval, &cont, len))
 988                         goto err;
 989                 break;
 990
 991                 case V_ASN1_INTEGER:
 992                 case V_ASN1_NEG_INTEGER:
 993                 case V_ASN1_ENUMERATED:
 994                 case V_ASN1_NEG_ENUMERATED:
 995                 tint = (ASN1_INTEGER **)pval;
 996                 if (!c2i_ASN1_INTEGER(tint, &cont, len))
 997                         goto err;
 998                 /* Fixup type to match the expected form */
 999                 (*tint)->type = utype | ((*tint)->type & V_ASN1_NEG);
1000                 break;
1001
1002                 case V_ASN1_OCTET_STRING:
1003                 case V_ASN1_NUMERICSTRING:
1004                 case V_ASN1_PRINTABLESTRING:
1005                 case V_ASN1_T61STRING:
1006                 case V_ASN1_VIDEOTEXSTRING:
1007                 case V_ASN1_IA5STRING:
1008                 case V_ASN1_UTCTIME:
1009                 case V_ASN1_GENERALIZEDTIME:
1010                 case V_ASN1_GRAPHICSTRING:
1011                 case V_ASN1_VISIBLESTRING:
1012                 case V_ASN1_GENERALSTRING:
1013                 case V_ASN1_UNIVERSALSTRING:
1014                 case V_ASN1_BMPSTRING:
1015                 case V_ASN1_UTF8STRING:
1016                 case V_ASN1_OTHER:
1017                 case V_ASN1_SET:
1018                 case V_ASN1_SEQUENCE:
1019                 default:
1020                 /* All based on ASN1_STRING and handled the same */
1021                 if (!*pval)
1022                         {
1023                         stmp = ASN1_STRING_type_new(utype);
1024                         if (!stmp)
1025                                 {
1026                                 ASN1err(ASN1_F_ASN1_EX_C2I,
1027                                                         ERR_R_MALLOC_FAILURE);
1028                                 goto err;
1029                                 }
1030                         *pval = (ASN1_VALUE *)stmp;
1031                         }
1032                 else
1033                         {
1034                         stmp = (ASN1_STRING *)*pval;
1035                         stmp->type = utype;
1036                         }
1037                 /* If we've already allocated a buffer use it */
1038                 if (*free_cont)
1039                         {
1040                         if (stmp->data)
1041                                 OPENSSL_free(stmp->data);
1042                         stmp->data = (unsigned char *)cont; /* UGLY CAST! RL */
1043                         stmp->length = len;
1044                         *free_cont = 0;
1045                         }
1046                 else
1047                         {
1048                         if (!ASN1_STRING_set(stmp, cont, len))
1049                                 {
1050                                 ASN1err(ASN1_F_ASN1_EX_C2I,
1051                                                         ERR_R_MALLOC_FAILURE);
1052                                 ASN1_STRING_free(stmp);
1053                                 *pval = NULL;
1054                                 goto err;
1055                                 }
1056                         }
1057                 break;
1058                 }
1059         /* If ASN1_ANY and NULL type fix up value */
1060         if (typ && (utype == V_ASN1_NULL))
1061                  typ->value.ptr = NULL;
1062
1063         ret = 1;
1064         err:
1065         if (!ret)
1066                 {
1067                 ASN1_TYPE_free(typ);
1068                 if (opval)
1069                         *opval = NULL;
1070                 }
1071         return ret;
1072         }
1073
1074
1075 /* This function finds the end of an ASN1 structure when passed its maximum
1076  * length, whether it is indefinite length and a pointer to the content.
1077  * This is more efficient than calling asn1_collect because it does not
1078  * recurse on each indefinite length header.
1079  */
1080
1081 static int asn1_find_end(const unsigned char **in, long len, char inf)
1082         {
1083         int expected_eoc;
1084         long plen;
1085         const unsigned char *p = *in, *q;
1086         /* If not indefinite length constructed just add length */
1087         if (inf == 0)
1088                 {
1089                 *in += len;
1090                 return 1;
1091                 }
1092         expected_eoc = 1;
1093         /* Indefinite length constructed form. Find the end when enough EOCs
1094          * are found. If more indefinite length constructed headers
1095          * are encountered increment the expected eoc count otherwise just
1096          * skip to the end of the data.
1097          */
1098         while (len > 0)
1099                 {
1100                 if(asn1_check_eoc(&p, len))
1101                         {
1102                         expected_eoc--;
1103                         if (expected_eoc == 0)
1104                                 break;
1105                         len -= 2;
1106                         continue;
1107                         }
1108                 q = p;
1109                 /* Just read in a header: only care about the length */
1110                 if(!asn1_check_tlen(&plen, NULL, NULL, &inf, NULL, &p, len,
1111                                 -1, 0, 0, NULL))
1112                         {
1113                         ASN1err(ASN1_F_ASN1_FIND_END, ERR_R_NESTED_ASN1_ERROR);
1114                         return 0;
1115                         }
1116                 if (inf)
1117                         expected_eoc++;
1118                 else
1119                         p += plen;
1120                 len -= p - q;
1121                 }
1122         if (expected_eoc)
1123                 {
1124                 ASN1err(ASN1_F_ASN1_FIND_END, ASN1_R_MISSING_EOC);
1125                 return 0;
1126                 }
1127         *in = p;
1128         return 1;
1129         }
1130 /* This function collects the asn1 data from a constructred string
1131  * type into a buffer. The values of 'in' and 'len' should refer
1132  * to the contents of the constructed type and 'inf' should be set
1133  * if it is indefinite length.
1134  */
1135
1136 static int asn1_collect(BUF_MEM *buf, const unsigned char **in, long len,
1137                                 char inf, int tag, int aclass)
1138         {
1139         const unsigned char *p, *q;
1140         long plen;
1141         char cst, ininf;
1142         p = *in;
1143         inf &= 1;
1144         /* If no buffer and not indefinite length constructed just pass over
1145          * the encoded data */
1146         if (!buf && !inf)
1147                 {
1148                 *in += len;
1149                 return 1;
1150                 }
1151         while(len > 0)
1152                 {
1153                 q = p;
1154                 /* Check for EOC */
1155                 if (asn1_check_eoc(&p, len))
1156                         {
1157                         /* EOC is illegal outside indefinite length
1158                          * constructed form */
1159                         if (!inf)
1160                                 {
1161                                 ASN1err(ASN1_F_ASN1_COLLECT,
1162                                         ASN1_R_UNEXPECTED_EOC);
1163                                 return 0;
1164                                 }
1165                         inf = 0;
1166                         break;
1167                         }
1168
1169                 if (!asn1_check_tlen(&plen, NULL, NULL, &ininf, &cst, &p,
1170                                         len, tag, aclass, 0, NULL))
1171                         {
1172                         ASN1err(ASN1_F_ASN1_COLLECT, ERR_R_NESTED_ASN1_ERROR);
1173                         return 0;
1174                         }
1175
1176                 /* If indefinite length constructed update max length */
1177                 if (cst)
1178                         {
1179 #ifdef OPENSSL_ALLOW_NESTED_ASN1_STRINGS
1180                         if (!asn1_collect(buf, &p, plen, ininf, tag, aclass))
1181                                 return 0;
1182 #else
1183                         ASN1err(ASN1_F_ASN1_COLLECT, ASN1_R_NESTED_ASN1_STRING);
1184                         return 0;
1185 #endif
1186                         }
1187                 else if (plen && !collect_data(buf, &p, plen))
1188                         return 0;
1189                 len -= p - q;
1190                 }
1191         if (inf)
1192                 {
1193                 ASN1err(ASN1_F_ASN1_COLLECT, ASN1_R_MISSING_EOC);
1194                 return 0;
1195                 }
1196         *in = p;
1197         return 1;
1198         }
1199
1200 static int collect_data(BUF_MEM *buf, const unsigned char **p, long plen)
1201         {
1202         int len;
1203         if (buf)
1204                 {
1205                 len = buf->length;
1206                 if (!BUF_MEM_grow_clean(buf, len + plen))
1207                         {
1208                         ASN1err(ASN1_F_COLLECT_DATA, ERR_R_MALLOC_FAILURE);
1209                         return 0;
1210                         }
1211                 memcpy(buf->data + len, *p, plen);
1212                 }
1213         *p += plen;
1214         return 1;
1215         }
1216
1217 /* Check for ASN1 EOC and swallow it if found */
1218
1219 static int asn1_check_eoc(const unsigned char **in, long len)
1220         {
1221         const unsigned char *p;
1222         if (len < 2) return 0;
1223         p = *in;
1224         if (!p[0] && !p[1])
1225                 {
1226                 *in += 2;
1227                 return 1;
1228                 }
1229         return 0;
1230         }
1231
1232 /* Check an ASN1 tag and length: a bit like ASN1_get_object
1233  * but it sets the length for indefinite length constructed
1234  * form, we don't know the exact length but we can set an
1235  * upper bound to the amount of data available minus the
1236  * header length just read.
1237  */
1238
1239 static int asn1_check_tlen(long *olen, int *otag, unsigned char *oclass,
1240                                 char *inf, char *cst,
1241                                 const unsigned char **in, long len,
1242                                 int exptag, int expclass, char opt,
1243                                 ASN1_TLC *ctx)
1244         {
1245         int i;
1246         int ptag, pclass;
1247         size_t plen;
1248         const unsigned char *p, *q;
1249         p = *in;
1250         q = p;
1251
1252         if (ctx && ctx->valid)
1253                 {
1254                 i = ctx->ret;
1255                 plen = ctx->plen;
1256                 pclass = ctx->pclass;
1257                 ptag = ctx->ptag;
1258                 p += ctx->hdrlen;
1259                 }
1260         else
1261                 {
1262                 i = ASN1_get_object(&p, &plen, &ptag, &pclass, len);
1263                 if (ctx)
1264                         {
1265                         ctx->ret = i;
1266                         ctx->plen = plen;
1267                         ctx->pclass = pclass;
1268                         ctx->ptag = ptag;
1269                         ctx->hdrlen = p - q;
1270                         ctx->valid = 1;
1271                         /* If definite length, and no error, length +
1272                          * header can't exceed total amount of data available.
1273                          */
1274                         if (!(i & 0x81) && ((plen + ctx->hdrlen) > len))
1275                                 {
1276                                 ASN1err(ASN1_F_ASN1_CHECK_TLEN,
1277                                                         ASN1_R_TOO_LONG);
1278                                 asn1_tlc_clear(ctx);
1279                                 return 0;
1280                                 }
1281                         }
1282                 }
1283
1284         if (i & 0x80)
1285                 {
1286                 ASN1err(ASN1_F_ASN1_CHECK_TLEN, ASN1_R_BAD_OBJECT_HEADER);
1287                 asn1_tlc_clear(ctx);
1288                 return 0;
1289                 }
1290         if (exptag >= 0)
1291                 {
1292                 if ((exptag != ptag) || (expclass != pclass))
1293                         {
1294                         /* If type is OPTIONAL, not an error:
1295                          * indicate missing type.
1296                          */
1297                         if (opt) return -1;
1298                         asn1_tlc_clear(ctx);
1299                         ASN1err(ASN1_F_ASN1_CHECK_TLEN, ASN1_R_WRONG_TAG);
1300                         return 0;
1301                         }
1302                 /* We have a tag and class match:
1303                  * assume we are going to do something with it */
1304                 asn1_tlc_clear(ctx);
1305                 }
1306
1307         if (i & 1)
1308                 plen = len - (p - q);
1309
1310         if (inf)
1311                 *inf = i & 1;
1312
1313         if (cst)
1314                 *cst = i & V_ASN1_CONSTRUCTED;
1315
1316         if (olen)
1317                 *olen = plen;
1318
1319         if (oclass)
1320                 *oclass = pclass;
1321
1322         if (otag)
1323                 *otag = ptag;
1324
1325         *in = p;
1326         return 1;
1327         }