crypto/asn1/tasn_dec.c

   1 /* tasn_dec.c */
   2 /* Written by Dr Stephen N Henson (steve@openssl.org) 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, int depth);
  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, long len, const ASN1_ITEM *it)
 130         {
 131         ASN1_TLC c;
 132         ASN1_VALUE *ptmpval = NULL;
 133         if (!pval)
 134                 pval = &ptmpval;
 135         asn1_tlc_clear_nc(&c);
 136         if (ASN1_item_ex_d2i(pval, in, len, it, -1, 0, 0, &c) > 0)
 137                 return *pval;
 138         return NULL;
 139         }
 140
 141 int ASN1_template_d2i(ASN1_VALUE **pval,
 142                 const unsigned char **in, long len, const ASN1_TEMPLATE *tt)
 143         {
 144         ASN1_TLC c;
 145         asn1_tlc_clear_nc(&c);
 146         return asn1_template_ex_d2i(pval, in, len, tt, 0, &c);
 147         }
 148
 149
 150 /* Decode an item, taking care of IMPLICIT tagging, if any.
 151  * If 'opt' set and tag mismatch return -1 to handle OPTIONAL
 152  */
 153
 154 int ASN1_item_ex_d2i(ASN1_VALUE **pval, const unsigned char **in, long len,
 155                         const ASN1_ITEM *it,
 156                         int tag, int aclass, char opt, ASN1_TLC *ctx)
 157         {
 158         const ASN1_TEMPLATE *tt, *errtt = NULL;
 159         const ASN1_COMPAT_FUNCS *cf;
 160         const ASN1_EXTERN_FUNCS *ef;
 161         const ASN1_AUX *aux = it->funcs;
 162         ASN1_aux_cb *asn1_cb;
 163         const unsigned char *p = NULL, *q;
 164         unsigned char *wp=NULL; /* BIG FAT WARNING!  BREAKS CONST WHERE USED */
 165         unsigned char imphack = 0, oclass;
 166         char seq_eoc, seq_nolen, cst, isopt;
 167         long tmplen;
 168         int i;
 169         int otag;
 170         int ret = 0;
 171         ASN1_VALUE *pchval, **pchptr, *ptmpval;
 172         if (!pval)
 173                 return 0;
 174         if (aux && aux->asn1_cb)
 175                 asn1_cb = aux->asn1_cb;
 176         else asn1_cb = 0;
 177
 178         switch(it->itype)
 179                 {
 180                 case ASN1_ITYPE_PRIMITIVE:
 181                 if (it->templates)
 182                         {
 183                         /* tagging or OPTIONAL is currently illegal on an item
 184                          * template because the flags can't get passed down.
 185                          * In practice this isn't a problem: we include the
 186                          * relevant flags from the item template in the
 187                          * template itself.
 188                          */
 189                         if ((tag != -1) || opt)
 190                                 {
 191                                 ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
 192                                 ASN1_R_ILLEGAL_OPTIONS_ON_ITEM_TEMPLATE);
 193                                 goto err;
 194                                 }
 195                         return asn1_template_ex_d2i(pval, in, len,
 196                                         it->templates, opt, ctx);
 197                 }
 198                 return asn1_d2i_ex_primitive(pval, in, len, it,
 199                                                 tag, aclass, opt, ctx);
 200                 break;
 201
 202                 case ASN1_ITYPE_MSTRING:
 203                 p = *in;
 204                 /* Just read in tag and class */
 205                 ret = asn1_check_tlen(NULL, &otag, &oclass, NULL, NULL,
 206                                                 &p, len, -1, 0, 1, ctx);
 207                 if (!ret)
 208                         {
 209                         ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
 210                                         ERR_R_NESTED_ASN1_ERROR);
 211                         goto err;
 212                         }
 213
 214                 /* Must be UNIVERSAL class */
 215                 if (oclass != V_ASN1_UNIVERSAL)
 216                         {
 217                         /* If OPTIONAL, assume this is OK */
 218                         if (opt) return -1;
 219                         ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
 220                                         ASN1_R_MSTRING_NOT_UNIVERSAL);
 221                         goto err;
 222                         }
 223                 /* Check tag matches bit map */
 224                 if (!(ASN1_tag2bit(otag) & it->utype))
 225                         {
 226                         /* If OPTIONAL, assume this is OK */
 227                         if (opt)
 228                                 return -1;
 229                         ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
 230                                         ASN1_R_MSTRING_WRONG_TAG);
 231                         goto err;
 232                         }
 233                 return asn1_d2i_ex_primitive(pval, in, len,
 234                                                 it, otag, 0, 0, ctx);
 235
 236                 case ASN1_ITYPE_EXTERN:
 237                 /* Use new style d2i */
 238                 ef = it->funcs;
 239                 return ef->asn1_ex_d2i(pval, in, len,
 240                                                 it, tag, aclass, opt, ctx);
 241
 242                 case ASN1_ITYPE_COMPAT:
 243                 /* we must resort to old style evil hackery */
 244                 cf = it->funcs;
 245
 246                 /* If OPTIONAL see if it is there */
 247                 if (opt)
 248                         {
 249                         int exptag;
 250                         p = *in;
 251                         if (tag == -1)
 252                                 exptag = it->utype;
 253                         else exptag = tag;
 254                         /* Don't care about anything other than presence
 255                          * of expected tag */
 256
 257                         ret = asn1_check_tlen(NULL, NULL, NULL, NULL, NULL,
 258                                         &p, len, exptag, aclass, 1, ctx);
 259                         if (!ret)
 260                                 {
 261                                 ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
 262                                         ERR_R_NESTED_ASN1_ERROR);
 263                                 goto err;
 264                                 }
 265                         if (ret == -1)
 266                                 return -1;
 267                         }
 268
 269                 /* This is the old style evil hack IMPLICIT handling:
 270                  * since the underlying code is expecting a tag and
 271                  * class other than the one present we change the
 272                  * buffer temporarily then change it back afterwards.
 273                  * This doesn't and never did work for tags > 30.
 274                  *
 275                  * Yes this is *horrible* but it is only needed for
 276                  * old style d2i which will hopefully not be around
 277                  * for much longer.
 278                  * FIXME: should copy the buffer then modify it so
 279                  * the input buffer can be const: we should *always*
 280                  * copy because the old style d2i might modify the
 281                  * buffer.
 282                  */
 283
 284                 if (tag != -1)
 285                         {
 286                         wp = *(unsigned char **)in;
 287                         imphack = *wp;
 288                         if (p == NULL)
 289                                 {
 290                                 ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
 291                                         ERR_R_NESTED_ASN1_ERROR);
 292                                 goto err;
 293                                 }
 294                         *wp = (unsigned char)((*p & V_ASN1_CONSTRUCTED)
 295                                                                 | it->utype);
 296                         }
 297
 298                 ptmpval = cf->asn1_d2i(pval, in, len);
 299
 300                 if (tag != -1)
 301                         *wp = imphack;
 302
 303                 if (ptmpval)
 304                         return 1;
 305
 306                 ASN1err(ASN1_F_ASN1_ITEM_EX_D2I, ERR_R_NESTED_ASN1_ERROR);
 307                 goto err;
 308
 309
 310                 case ASN1_ITYPE_CHOICE:
 311                 if (asn1_cb && !asn1_cb(ASN1_OP_D2I_PRE, pval, it, NULL))
 312                                 goto auxerr;
 313
 314                 /* Allocate structure */
 315                 if (!*pval && !ASN1_item_ex_new(pval, it))
 316                         {
 317                         ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
 318                                                 ERR_R_NESTED_ASN1_ERROR);
 319                         goto err;
 320                         }
 321                 /* CHOICE type, try each possibility in turn */
 322                 pchval = NULL;
 323                 p = *in;
 324                 for (i = 0, tt=it->templates; i < it->tcount; i++, tt++)
 325                         {
 326                         pchptr = asn1_get_field_ptr(pval, tt);
 327                         /* We mark field as OPTIONAL so its absence
 328                          * can be recognised.
 329                          */
 330                         ret = asn1_template_ex_d2i(pchptr, &p, len, tt, 1, ctx);
 331                         /* If field not present, try the next one */
 332                         if (ret == -1)
 333                                 continue;
 334                         /* If positive return, read OK, break loop */
 335                         if (ret > 0)
 336                                 break;
 337                         /* Otherwise must be an ASN1 parsing error */
 338                         errtt = tt;
 339                         ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
 340                                                 ERR_R_NESTED_ASN1_ERROR);
 341                         goto err;
 342                         }
 343
 344                 /* Did we fall off the end without reading anything? */
 345                 if (i == it->tcount)
 346                         {
 347                         /* If OPTIONAL, this is OK */
 348                         if (opt)
 349                                 {
 350                                 /* Free and zero it */
 351                                 ASN1_item_ex_free(pval, it);
 352                                 return -1;
 353                                 }
 354                         ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
 355                                         ASN1_R_NO_MATCHING_CHOICE_TYPE);
 356                         goto err;
 357                         }
 358
 359                 asn1_set_choice_selector(pval, i, it);
 360                 *in = p;
 361                 if (asn1_cb && !asn1_cb(ASN1_OP_D2I_POST, pval, it, NULL))
 362                                 goto auxerr;
 363                 return 1;
 364
 365                 case ASN1_ITYPE_NDEF_SEQUENCE:
 366                 case ASN1_ITYPE_SEQUENCE:
 367                 p = *in;
 368                 tmplen = len;
 369
 370                 /* If no IMPLICIT tagging set to SEQUENCE, UNIVERSAL */
 371                 if (tag == -1)
 372                         {
 373                         tag = V_ASN1_SEQUENCE;
 374                         aclass = V_ASN1_UNIVERSAL;
 375                         }
 376                 /* Get SEQUENCE length and update len, p */
 377                 ret = asn1_check_tlen(&len, NULL, NULL, &seq_eoc, &cst,
 378                                         &p, len, tag, aclass, opt, ctx);
 379                 if (!ret)
 380                         {
 381                         ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
 382                                         ERR_R_NESTED_ASN1_ERROR);
 383                         goto err;
 384                         }
 385                 else if (ret == -1)
 386                         return -1;
 387                 if (aux && (aux->flags & ASN1_AFLG_BROKEN))
 388                         {
 389                         len = tmplen - (p - *in);
 390                         seq_nolen = 1;
 391                         }
 392                 /* If indefinite we don't do a length check */
 393                 else seq_nolen = seq_eoc;
 394                 if (!cst)
 395                         {
 396                         ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
 397                                 ASN1_R_SEQUENCE_NOT_CONSTRUCTED);
 398                         goto err;
 399                         }
 400
 401                 if (!*pval && !ASN1_item_ex_new(pval, it))
 402                         {
 403                         ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
 404                                 ERR_R_NESTED_ASN1_ERROR);
 405                         goto err;
 406                         }
 407
 408                 if (asn1_cb && !asn1_cb(ASN1_OP_D2I_PRE, pval, it, NULL))
 409                                 goto auxerr;
 410
 411                 /* Get each field entry */
 412                 for (i = 0, tt = it->templates; i < it->tcount; i++, tt++)
 413                         {
 414                         const ASN1_TEMPLATE *seqtt;
 415                         ASN1_VALUE **pseqval;
 416                         seqtt = asn1_do_adb(pval, tt, 1);
 417                         if (!seqtt)
 418                                 goto err;
 419                         pseqval = asn1_get_field_ptr(pval, seqtt);
 420                         /* Have we ran out of data? */
 421                         if (!len)
 422                                 break;
 423                         q = p;
 424                         if (asn1_check_eoc(&p, len))
 425                                 {
 426                                 if (!seq_eoc)
 427                                         {
 428                                         ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
 429                                                         ASN1_R_UNEXPECTED_EOC);
 430                                         goto err;
 431                                         }
 432                                 len -= p - q;
 433                                 seq_eoc = 0;
 434                                 q = p;
 435                                 break;
 436                                 }
 437                         /* This determines the OPTIONAL flag value. The field
 438                          * cannot be omitted if it is the last of a SEQUENCE
 439                          * and there is still data to be read. This isn't
 440                          * strictly necessary but it increases efficiency in
 441                          * some cases.
 442                          */
 443                         if (i == (it->tcount - 1))
 444                                 isopt = 0;
 445                         else isopt = (char)(seqtt->flags & ASN1_TFLG_OPTIONAL);
 446                         /* attempt to read in field, allowing each to be
 447                          * OPTIONAL */
 448
 449                         ret = asn1_template_ex_d2i(pseqval, &p, len,
 450                                                         seqtt, isopt, ctx);
 451                         if (!ret)
 452                                 {
 453                                 errtt = seqtt;
 454                                 goto err;
 455                                 }
 456                         else if (ret == -1)
 457                                 {
 458                                 /* OPTIONAL component absent.
 459                                  * Free and zero the field.
 460                                  */
 461                                 ASN1_template_free(pseqval, seqtt);
 462                                 continue;
 463                                 }
 464                         /* Update length */
 465                         len -= p - q;
 466                         }
 467
 468                 /* Check for EOC if expecting one */
 469                 if (seq_eoc && !asn1_check_eoc(&p, len))
 470                         {
 471                         ASN1err(ASN1_F_ASN1_ITEM_EX_D2I, ASN1_R_MISSING_EOC);
 472                         goto err;
 473                         }
 474                 /* Check all data read */
 475                 if (!seq_nolen && len)
 476                         {
 477                         ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
 478                                         ASN1_R_SEQUENCE_LENGTH_MISMATCH);
 479                         goto err;
 480                         }
 481
 482                 /* If we get here we've got no more data in the SEQUENCE,
 483                  * however we may not have read all fields so check all
 484                  * remaining are OPTIONAL and clear any that are.
 485                  */
 486                 for (; i < it->tcount; tt++, i++)
 487                         {
 488                         const ASN1_TEMPLATE *seqtt;
 489                         seqtt = asn1_do_adb(pval, tt, 1);
 490                         if (!seqtt)
 491                                 goto err;
 492                         if (seqtt->flags & ASN1_TFLG_OPTIONAL)
 493                                 {
 494                                 ASN1_VALUE **pseqval;
 495                                 pseqval = asn1_get_field_ptr(pval, seqtt);
 496                                 ASN1_template_free(pseqval, seqtt);
 497                                 }
 498                         else
 499                                 {
 500                                 errtt = seqtt;
 501                                 ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
 502                                                         ASN1_R_FIELD_MISSING);
 503                                 goto err;
 504                                 }
 505                         }
 506                 /* Save encoding */
 507                 if (!asn1_enc_save(pval, *in, p - *in, it))
 508                         goto auxerr;
 509                 *in = p;
 510                 if (asn1_cb && !asn1_cb(ASN1_OP_D2I_POST, pval, it, NULL))
 511                                 goto auxerr;
 512                 return 1;
 513
 514                 default:
 515                 return 0;
 516                 }
 517         auxerr:
 518         ASN1err(ASN1_F_ASN1_ITEM_EX_D2I, ASN1_R_AUX_ERROR);
 519         err:
 520         ASN1_item_ex_free(pval, it);
 521         if (errtt)
 522                 ERR_add_error_data(4, "Field=", errtt->field_name,
 523                                         ", Type=", it->sname);
 524         else
 525                 ERR_add_error_data(2, "Type=", it->sname);
 526         return 0;
 527         }
 528
 529 /* Templates are handled with two separate functions.
 530  * One handles any EXPLICIT tag and the other handles the rest.
 531  */
 532
 533 static int asn1_template_ex_d2i(ASN1_VALUE **val,
 534                                 const unsigned char **in, long inlen,
 535                                 const ASN1_TEMPLATE *tt, char opt,
 536                                                         ASN1_TLC *ctx)
 537         {
 538         int flags, aclass;
 539         int ret;
 540         long len;
 541         const unsigned char *p, *q;
 542         char exp_eoc;
 543         if (!val)
 544                 return 0;
 545         flags = tt->flags;
 546         aclass = flags & ASN1_TFLG_TAG_CLASS;
 547
 548         p = *in;
 549
 550         /* Check if EXPLICIT tag expected */
 551         if (flags & ASN1_TFLG_EXPTAG)
 552                 {
 553                 char cst;
 554                 /* Need to work out amount of data available to the inner
 555                  * content and where it starts: so read in EXPLICIT header to
 556                  * get the info.
 557                  */
 558                 ret = asn1_check_tlen(&len, NULL, NULL, &exp_eoc, &cst,
 559                                         &p, inlen, tt->tag, aclass, opt, ctx);
 560                 q = p;
 561                 if (!ret)
 562                         {
 563                         ASN1err(ASN1_F_ASN1_TEMPLATE_EX_D2I,
 564                                         ERR_R_NESTED_ASN1_ERROR);
 565                         return 0;
 566                         }
 567                 else if (ret == -1)
 568                         return -1;
 569                 if (!cst)
 570                         {
 571                         ASN1err(ASN1_F_ASN1_TEMPLATE_EX_D2I,
 572                                         ASN1_R_EXPLICIT_TAG_NOT_CONSTRUCTED);
 573                         return 0;
 574                         }
 575                 /* We've found the field so it can't be OPTIONAL now */
 576                 ret = asn1_template_noexp_d2i(val, &p, len, tt, 0, ctx);
 577                 if (!ret)
 578                         {
 579                         ASN1err(ASN1_F_ASN1_TEMPLATE_EX_D2I,
 580                                         ERR_R_NESTED_ASN1_ERROR);
 581                         return 0;
 582                         }
 583                 /* We read the field in OK so update length */
 584                 len -= p - q;
 585                 if (exp_eoc)
 586                         {
 587                         /* If NDEF we must have an EOC here */
 588                         if (!asn1_check_eoc(&p, len))
 589                                 {
 590                                 ASN1err(ASN1_F_ASN1_TEMPLATE_EX_D2I,
 591                                                 ASN1_R_MISSING_EOC);
 592                                 goto err;
 593                                 }
 594                         }
 595                 else
 596                         {
 597                         /* Otherwise we must hit the EXPLICIT tag end or its
 598                          * an error */
 599                         if (len)
 600                                 {
 601                                 ASN1err(ASN1_F_ASN1_TEMPLATE_EX_D2I,
 602                                         ASN1_R_EXPLICIT_LENGTH_MISMATCH);
 603                                 goto err;
 604                                 }
 605                         }
 606                 }
 607                 else
 608                         return asn1_template_noexp_d2i(val, in, inlen,
 609                                                                 tt, opt, ctx);
 610
 611         *in = p;
 612         return 1;
 613
 614         err:
 615         ASN1_template_free(val, tt);
 616         *val = NULL;
 617         return 0;
 618         }
 619
 620 static int asn1_template_noexp_d2i(ASN1_VALUE **val,
 621                                 const unsigned char **in, long len,
 622                                 const ASN1_TEMPLATE *tt, char opt,
 623                                 ASN1_TLC *ctx)
 624         {
 625         int flags, aclass;
 626         int ret;
 627         const unsigned char *p, *q;
 628         if (!val)
 629                 return 0;
 630         flags = tt->flags;
 631         aclass = flags & ASN1_TFLG_TAG_CLASS;
 632
 633         p = *in;
 634         q = p;
 635
 636         if (flags & ASN1_TFLG_SK_MASK)
 637                 {
 638                 /* SET OF, SEQUENCE OF */
 639                 int sktag, skaclass;
 640                 char sk_eoc;
 641                 /* First work out expected inner tag value */
 642                 if (flags & ASN1_TFLG_IMPTAG)
 643                         {
 644                         sktag = tt->tag;
 645                         skaclass = aclass;
 646                         }
 647                 else
 648                         {
 649                         skaclass = V_ASN1_UNIVERSAL;
 650                         if (flags & ASN1_TFLG_SET_OF)
 651                                 sktag = V_ASN1_SET;
 652                         else
 653                                 sktag = V_ASN1_SEQUENCE;
 654                         }
 655                 /* Get the tag */
 656                 ret = asn1_check_tlen(&len, NULL, NULL, &sk_eoc, NULL,
 657                                         &p, len, sktag, skaclass, opt, ctx);
 658                 if (!ret)
 659                         {
 660                         ASN1err(ASN1_F_ASN1_TEMPLATE_NOEXP_D2I,
 661                                                 ERR_R_NESTED_ASN1_ERROR);
 662                         return 0;
 663                         }
 664                 else if (ret == -1)
 665                         return -1;
 666                 if (!*val)
 667                         *val = (ASN1_VALUE *)sk_new_null();
 668                 else
 669                         {
 670                         /* We've got a valid STACK: free up any items present */
 671                         STACK_OF(ASN1_VALUE) *sktmp
 672                             = (STACK_OF(ASN1_VALUE) *)*val;
 673                         ASN1_VALUE *vtmp;
 674                         while(sk_ASN1_VALUE_num(sktmp) > 0)
 675                                 {
 676                                 vtmp = sk_ASN1_VALUE_pop(sktmp);
 677                                 ASN1_item_ex_free(&vtmp,
 678                                                 ASN1_ITEM_ptr(tt->item));
 679                                 }
 680                         }
 681
 682                 if (!*val)
 683                         {
 684                         ASN1err(ASN1_F_ASN1_TEMPLATE_NOEXP_D2I,
 685                                                 ERR_R_MALLOC_FAILURE);
 686                         goto err;
 687                         }
 688
 689                 /* Read as many items as we can */
 690                 while(len > 0)
 691                         {
 692                         ASN1_VALUE *skfield;
 693                         q = p;
 694                         /* See if EOC found */
 695                         if (asn1_check_eoc(&p, len))
 696                                 {
 697                                 if (!sk_eoc)
 698                                         {
 699                                         ASN1err(ASN1_F_ASN1_TEMPLATE_NOEXP_D2I,
 700                                                         ASN1_R_UNEXPECTED_EOC);
 701                                         goto err;
 702                                         }
 703                                 len -= p - q;
 704                                 sk_eoc = 0;
 705                                 break;
 706                                 }
 707                         skfield = NULL;
 708                         if (!ASN1_item_ex_d2i(&skfield, &p, len,
 709                                                 ASN1_ITEM_ptr(tt->item),
 710                                                 -1, 0, 0, ctx))
 711                                 {
 712                                 ASN1err(ASN1_F_ASN1_TEMPLATE_NOEXP_D2I,
 713                                         ERR_R_NESTED_ASN1_ERROR);
 714                                 goto err;
 715                                 }
 716                         len -= p - q;
 717                         if (!sk_ASN1_VALUE_push((STACK_OF(ASN1_VALUE) *)*val,
 718                                                 skfield))
 719                                 {
 720                                 ASN1err(ASN1_F_ASN1_TEMPLATE_NOEXP_D2I,
 721                                                 ERR_R_MALLOC_FAILURE);
 722                                 goto err;
 723                                 }
 724                         }
 725                 if (sk_eoc)
 726                         {
 727                         ASN1err(ASN1_F_ASN1_TEMPLATE_NOEXP_D2I, ASN1_R_MISSING_EOC);
 728                         goto err;
 729                         }
 730                 }
 731         else if (flags & ASN1_TFLG_IMPTAG)
 732                 {
 733                 /* IMPLICIT tagging */
 734                 ret = ASN1_item_ex_d2i(val, &p, len,
 735                         ASN1_ITEM_ptr(tt->item), tt->tag, aclass, opt, ctx);
 736                 if (!ret)
 737                         {
 738                         ASN1err(ASN1_F_ASN1_TEMPLATE_NOEXP_D2I,
 739                                                 ERR_R_NESTED_ASN1_ERROR);
 740                         goto err;
 741                         }
 742                 else if (ret == -1)
 743                         return -1;
 744                 }
 745         else
 746                 {
 747                 /* Nothing special */
 748                 ret = ASN1_item_ex_d2i(val, &p, len, ASN1_ITEM_ptr(tt->item),
 749                                                         -1, 0, opt, ctx);
 750                 if (!ret)
 751                         {
 752                         ASN1err(ASN1_F_ASN1_TEMPLATE_NOEXP_D2I,
 753                                         ERR_R_NESTED_ASN1_ERROR);
 754                         goto err;
 755                         }
 756                 else if (ret == -1)
 757                         return -1;
 758                 }
 759
 760         *in = p;
 761         return 1;
 762
 763         err:
 764         ASN1_template_free(val, tt);
 765         *val = NULL;
 766         return 0;
 767         }
 768
 769 static int asn1_d2i_ex_primitive(ASN1_VALUE **pval,
 770                                 const unsigned char **in, long inlen,
 771                                 const ASN1_ITEM *it,
 772                                 int tag, int aclass, char opt, ASN1_TLC *ctx)
 773         {
 774         int ret = 0, utype;
 775         long plen;
 776         char cst, inf, free_cont = 0;
 777         const unsigned char *p;
 778         BUF_MEM buf;
 779         const unsigned char *cont = NULL;
 780         long len;
 781         if (!pval)
 782                 {
 783                 ASN1err(ASN1_F_ASN1_D2I_EX_PRIMITIVE, ASN1_R_ILLEGAL_NULL);
 784                 return 0; /* Should never happen */
 785                 }
 786
 787         if (it->itype == ASN1_ITYPE_MSTRING)
 788                 {
 789                 utype = tag;
 790                 tag = -1;
 791                 }
 792         else
 793                 utype = it->utype;
 794
 795         if (utype == V_ASN1_ANY)
 796                 {
 797                 /* If type is ANY need to figure out type from tag */
 798                 unsigned char oclass;
 799                 if (tag >= 0)
 800                         {
 801                         ASN1err(ASN1_F_ASN1_D2I_EX_PRIMITIVE,
 802                                         ASN1_R_ILLEGAL_TAGGED_ANY);
 803                         return 0;
 804                         }
 805                 if (opt)
 806                         {
 807                         ASN1err(ASN1_F_ASN1_D2I_EX_PRIMITIVE,
 808                                         ASN1_R_ILLEGAL_OPTIONAL_ANY);
 809                         return 0;
 810                         }
 811                 p = *in;
 812                 ret = asn1_check_tlen(NULL, &utype, &oclass, NULL, NULL,
 813                                         &p, inlen, -1, 0, 0, ctx);
 814                 if (!ret)
 815                         {
 816                         ASN1err(ASN1_F_ASN1_D2I_EX_PRIMITIVE,
 817                                         ERR_R_NESTED_ASN1_ERROR);
 818                         return 0;
 819                         }
 820                 if (oclass != V_ASN1_UNIVERSAL)
 821                         utype = V_ASN1_OTHER;
 822                 }
 823         if (tag == -1)
 824                 {
 825                 tag = utype;
 826                 aclass = V_ASN1_UNIVERSAL;
 827                 }
 828         p = *in;
 829         /* Check header */
 830         ret = asn1_check_tlen(&plen, NULL, NULL, &inf, &cst,
 831                                 &p, inlen, tag, aclass, opt, ctx);
 832         if (!ret)
 833                 {
 834                 ASN1err(ASN1_F_ASN1_D2I_EX_PRIMITIVE, ERR_R_NESTED_ASN1_ERROR);
 835                 return 0;
 836                 }
 837         else if (ret == -1)
 838                 return -1;
 839         ret = 0;
 840         /* SEQUENCE, SET and "OTHER" are left in encoded form */
 841         if ((utype == V_ASN1_SEQUENCE)
 842                 || (utype == V_ASN1_SET) || (utype == V_ASN1_OTHER))
 843                 {
 844                 /* Clear context cache for type OTHER because the auto clear
 845                  * when we have a exact match wont work
 846                  */
 847                 if (utype == V_ASN1_OTHER)
 848                         {
 849                         asn1_tlc_clear(ctx);
 850                         }
 851                 /* SEQUENCE and SET must be constructed */
 852                 else if (!cst)
 853                         {
 854                         ASN1err(ASN1_F_ASN1_D2I_EX_PRIMITIVE,
 855                                 ASN1_R_TYPE_NOT_CONSTRUCTED);
 856                         return 0;
 857                         }
 858
 859                 cont = *in;
 860                 /* If indefinite length constructed find the real end */
 861                 if (inf)
 862                         {
 863                         if (!asn1_find_end(&p, plen, inf))
 864                                  goto err;
 865                         len = p - cont;
 866                         }
 867                 else
 868                         {
 869                         len = p - cont + plen;
 870                         p += plen;
 871                         buf.data = NULL;
 872                         }
 873                 }
 874         else if (cst)
 875                 {
 876                 buf.length = 0;
 877                 buf.max = 0;
 878                 buf.data = NULL;
 879                 /* Should really check the internal tags are correct but
 880                  * some things may get this wrong. The relevant specs
 881                  * say that constructed string types should be OCTET STRINGs
 882                  * internally irrespective of the type. So instead just check
 883                  * for UNIVERSAL class and ignore the tag.
 884                  */
 885                 if (!asn1_collect(&buf, &p, plen, inf, -1, V_ASN1_UNIVERSAL, 0))
 886                         {
 887                         free_cont = 1;
 888                         goto err;
 889                         }
 890                 len = buf.length;
 891                 /* Append a final null to string */
 892                 if (!BUF_MEM_grow_clean(&buf, len + 1))
 893                         {
 894                         ASN1err(ASN1_F_ASN1_D2I_EX_PRIMITIVE,
 895                                                 ERR_R_MALLOC_FAILURE);
 896                         return 0;
 897                         }
 898                 buf.data[len] = 0;
 899                 cont = (const unsigned char *)buf.data;
 900                 free_cont = 1;
 901                 }
 902         else
 903                 {
 904                 cont = p;
 905                 len = plen;
 906                 p += plen;
 907                 }
 908
 909         /* We now have content length and type: translate into a structure */
 910         if (!asn1_ex_c2i(pval, cont, len, utype, &free_cont, it))
 911                 goto err;
 912
 913         *in = p;
 914         ret = 1;
 915         err:
 916         if (free_cont && buf.data) OPENSSL_free(buf.data);
 917         return ret;
 918         }
 919
 920 /* Translate ASN1 content octets into a structure */
 921
 922 int asn1_ex_c2i(ASN1_VALUE **pval, const unsigned char *cont, int len,
 923                         int utype, char *free_cont, const ASN1_ITEM *it)
 924         {
 925         ASN1_VALUE **opval = NULL;
 926         ASN1_STRING *stmp;
 927         ASN1_TYPE *typ = NULL;
 928         int ret = 0;
 929         const ASN1_PRIMITIVE_FUNCS *pf;
 930         ASN1_INTEGER **tint;
 931         pf = it->funcs;
 932
 933         if (pf && pf->prim_c2i)
 934                 return pf->prim_c2i(pval, cont, len, utype, free_cont, it);
 935         /* If ANY type clear type and set pointer to internal value */
 936         if (it->utype == V_ASN1_ANY)
 937                 {
 938                 if (!*pval)
 939                         {
 940                         typ = ASN1_TYPE_new();
 941                         if (typ == NULL)
 942                                 goto err;
 943                         *pval = (ASN1_VALUE *)typ;
 944                         }
 945                 else
 946                         typ = (ASN1_TYPE *)*pval;
 947
 948                 if (utype != typ->type)
 949                         ASN1_TYPE_set(typ, utype, NULL);
 950                 opval = pval;
 951                 pval = &typ->value.asn1_value;
 952                 }
 953         switch(utype)
 954                 {
 955                 case V_ASN1_OBJECT:
 956                 if (!c2i_ASN1_OBJECT((ASN1_OBJECT **)pval, &cont, len))
 957                         goto err;
 958                 break;
 959
 960                 case V_ASN1_NULL:
 961                 if (len)
 962                         {
 963                         ASN1err(ASN1_F_ASN1_EX_C2I,
 964                                                 ASN1_R_NULL_IS_WRONG_LENGTH);
 965                         goto err;
 966                         }
 967                 *pval = (ASN1_VALUE *)1;
 968                 break;
 969
 970                 case V_ASN1_BOOLEAN:
 971                 if (len != 1)
 972                         {
 973                         ASN1err(ASN1_F_ASN1_EX_C2I,
 974                                                 ASN1_R_BOOLEAN_IS_WRONG_LENGTH);
 975                         goto err;
 976                         }
 977                 else
 978                         {
 979                         ASN1_BOOLEAN *tbool;
 980                         tbool = (ASN1_BOOLEAN *)pval;
 981                         *tbool = *cont;
 982                         }
 983                 break;
 984
 985                 case V_ASN1_BIT_STRING:
 986                 if (!c2i_ASN1_BIT_STRING((ASN1_BIT_STRING **)pval, &cont, len))
 987                         goto err;
 988                 break;
 989
 990                 case V_ASN1_INTEGER:
 991                 case V_ASN1_NEG_INTEGER:
 992                 case V_ASN1_ENUMERATED:
 993                 case V_ASN1_NEG_ENUMERATED:
 994                 tint = (ASN1_INTEGER **)pval;
 995                 if (!c2i_ASN1_INTEGER(tint, &cont, len))
 996                         goto err;
 997                 /* Fixup type to match the expected form */
 998                 (*tint)->type = utype | ((*tint)->type & V_ASN1_NEG);
 999                 break;
1000
1001                 case V_ASN1_OCTET_STRING:
1002                 case V_ASN1_NUMERICSTRING:
1003                 case V_ASN1_PRINTABLESTRING:
1004                 case V_ASN1_T61STRING:
1005                 case V_ASN1_VIDEOTEXSTRING:
1006                 case V_ASN1_IA5STRING:
1007                 case V_ASN1_UTCTIME:
1008                 case V_ASN1_GENERALIZEDTIME:
1009                 case V_ASN1_GRAPHICSTRING:
1010                 case V_ASN1_VISIBLESTRING:
1011                 case V_ASN1_GENERALSTRING:
1012                 case V_ASN1_UNIVERSALSTRING:
1013                 case V_ASN1_BMPSTRING:
1014                 case V_ASN1_UTF8STRING:
1015                 case V_ASN1_OTHER:
1016                 case V_ASN1_SET:
1017                 case V_ASN1_SEQUENCE:
1018                 default:
1019                 /* All based on ASN1_STRING and handled the same */
1020                 if (!*pval)
1021                         {
1022                         stmp = ASN1_STRING_type_new(utype);
1023                         if (!stmp)
1024                                 {
1025                                 ASN1err(ASN1_F_ASN1_EX_C2I,
1026                                                         ERR_R_MALLOC_FAILURE);
1027                                 goto err;
1028                                 }
1029                         *pval = (ASN1_VALUE *)stmp;
1030                         }
1031                 else
1032                         {
1033                         stmp = (ASN1_STRING *)*pval;
1034                         stmp->type = utype;
1035                         }
1036                 /* If we've already allocated a buffer use it */
1037                 if (*free_cont)
1038                         {
1039                         if (stmp->data)
1040                                 OPENSSL_free(stmp->data);
1041                         stmp->data = (unsigned char *)cont; /* UGLY CAST! RL */
1042                         stmp->length = len;
1043                         *free_cont = 0;
1044                         }
1045                 else
1046                         {
1047                         if (!ASN1_STRING_set(stmp, cont, len))
1048                                 {
1049                                 ASN1err(ASN1_F_ASN1_EX_C2I,
1050                                                         ERR_R_MALLOC_FAILURE);
1051                                 ASN1_STRING_free(stmp);
1052                                 *pval = NULL;
1053                                 goto err;
1054                                 }
1055                         }
1056                 break;
1057                 }
1058         /* If ASN1_ANY and NULL type fix up value */
1059         if (typ && (utype == V_ASN1_NULL))
1060                  typ->value.ptr = NULL;
1061
1062         ret = 1;
1063         err:
1064         if (!ret)
1065                 {
1066                 ASN1_TYPE_free(typ);
1067                 if (opval)
1068                         *opval = NULL;
1069                 }
1070         return ret;
1071         }
1072
1073
1074 /* This function finds the end of an ASN1 structure when passed its maximum
1075  * length, whether it is indefinite length and a pointer to the content.
1076  * This is more efficient than calling asn1_collect because it does not
1077  * recurse on each indefinite length header.
1078  */
1079
1080 static int asn1_find_end(const unsigned char **in, long len, char inf)
1081         {
1082         int expected_eoc;
1083         long plen;
1084         const unsigned char *p = *in, *q;
1085         /* If not indefinite length constructed just add length */
1086         if (inf == 0)
1087                 {
1088                 *in += len;
1089                 return 1;
1090                 }
1091         expected_eoc = 1;
1092         /* Indefinite length constructed form. Find the end when enough EOCs
1093          * are found. If more indefinite length constructed headers
1094          * are encountered increment the expected eoc count otherwise just
1095          * skip to the end of the data.
1096          */
1097         while (len > 0)
1098                 {
1099                 if(asn1_check_eoc(&p, len))
1100                         {
1101                         expected_eoc--;
1102                         if (expected_eoc == 0)
1103                                 break;
1104                         len -= 2;
1105                         continue;
1106                         }
1107                 q = p;
1108                 /* Just read in a header: only care about the length */
1109                 if(!asn1_check_tlen(&plen, NULL, NULL, &inf, NULL, &p, len,
1110                                 -1, 0, 0, NULL))
1111                         {
1112                         ASN1err(ASN1_F_ASN1_FIND_END, ERR_R_NESTED_ASN1_ERROR);
1113                         return 0;
1114                         }
1115                 if (inf)
1116                         expected_eoc++;
1117                 else
1118                         p += plen;
1119                 len -= p - q;
1120                 }
1121         if (expected_eoc)
1122                 {
1123                 ASN1err(ASN1_F_ASN1_FIND_END, ASN1_R_MISSING_EOC);
1124                 return 0;
1125                 }
1126         *in = p;
1127         return 1;
1128         }
1129 /* This function collects the asn1 data from a constructred string
1130  * type into a buffer. The values of 'in' and 'len' should refer
1131  * to the contents of the constructed type and 'inf' should be set
1132  * if it is indefinite length.
1133  */
1134
1135 #ifndef ASN1_MAX_STRING_NEST
1136 /* This determines how many levels of recursion are permitted in ASN1
1137  * string types. If it is not limited stack overflows can occur. If set
1138  * to zero no recursion is allowed at all. Although zero should be adequate
1139  * examples exist that require a value of 1. So 5 should be more than enough.
1140  */
1141 #define ASN1_MAX_STRING_NEST 5
1142 #endif
1143
1144
1145 static int asn1_collect(BUF_MEM *buf, const unsigned char **in, long len,
1146                         char inf, int tag, int aclass, int depth)
1147         {
1148         const unsigned char *p, *q;
1149         long plen;
1150         char cst, ininf;
1151         p = *in;
1152         inf &= 1;
1153         /* If no buffer and not indefinite length constructed just pass over
1154          * the encoded data */
1155         if (!buf && !inf)
1156                 {
1157                 *in += len;
1158                 return 1;
1159                 }
1160         while(len > 0)
1161                 {
1162                 q = p;
1163                 /* Check for EOC */
1164                 if (asn1_check_eoc(&p, len))
1165                         {
1166                         /* EOC is illegal outside indefinite length
1167                          * constructed form */
1168                         if (!inf)
1169                                 {
1170                                 ASN1err(ASN1_F_ASN1_COLLECT,
1171                                         ASN1_R_UNEXPECTED_EOC);
1172                                 return 0;
1173                                 }
1174                         inf = 0;
1175                         break;
1176                         }
1177
1178                 if (!asn1_check_tlen(&plen, NULL, NULL, &ininf, &cst, &p,
1179                                         len, tag, aclass, 0, NULL))
1180                         {
1181                         ASN1err(ASN1_F_ASN1_COLLECT, ERR_R_NESTED_ASN1_ERROR);
1182                         return 0;
1183                         }
1184
1185                 /* If indefinite length constructed update max length */
1186                 if (cst)
1187                         {
1188                         if (depth >= ASN1_MAX_STRING_NEST)
1189                                 {
1190                                 ASN1err(ASN1_F_ASN1_COLLECT,
1191                                         ASN1_R_NESTED_ASN1_STRING);
1192                                 return 0;
1193                                 }
1194                         if (!asn1_collect(buf, &p, plen, ininf, tag, aclass,
1195                                                 depth + 1))
1196                                 return 0;
1197                         }
1198                 else if (plen && !collect_data(buf, &p, plen))
1199                         return 0;
1200                 len -= p - q;
1201                 }
1202         if (inf)
1203                 {
1204                 ASN1err(ASN1_F_ASN1_COLLECT, ASN1_R_MISSING_EOC);
1205                 return 0;
1206                 }
1207         *in = p;
1208         return 1;
1209         }
1210
1211 static int collect_data(BUF_MEM *buf, const unsigned char **p, long plen)
1212         {
1213         int len;
1214         if (buf)
1215                 {
1216                 len = buf->length;
1217                 if (!BUF_MEM_grow_clean(buf, len + plen))
1218                         {
1219                         ASN1err(ASN1_F_COLLECT_DATA, ERR_R_MALLOC_FAILURE);
1220                         return 0;
1221                         }
1222                 memcpy(buf->data + len, *p, plen);
1223                 }
1224         *p += plen;
1225         return 1;
1226         }
1227
1228 /* Check for ASN1 EOC and swallow it if found */
1229
1230 static int asn1_check_eoc(const unsigned char **in, long len)
1231         {
1232         const unsigned char *p;
1233         if (len < 2) return 0;
1234         p = *in;
1235         if (!p[0] && !p[1])
1236                 {
1237                 *in += 2;
1238                 return 1;
1239                 }
1240         return 0;
1241         }
1242
1243 /* Check an ASN1 tag and length: a bit like ASN1_get_object
1244  * but it sets the length for indefinite length constructed
1245  * form, we don't know the exact length but we can set an
1246  * upper bound to the amount of data available minus the
1247  * header length just read.
1248  */
1249
1250 static int asn1_check_tlen(long *olen, int *otag, unsigned char *oclass,
1251                                 char *inf, char *cst,
1252                                 const unsigned char **in, long len,
1253                                 int exptag, int expclass, char opt,
1254                                 ASN1_TLC *ctx)
1255         {
1256         int i;
1257         int ptag, pclass;
1258         long plen;
1259         const unsigned char *p, *q;
1260         p = *in;
1261         q = p;
1262
1263         if (ctx && ctx->valid)
1264                 {
1265                 i = ctx->ret;
1266                 plen = ctx->plen;
1267                 pclass = ctx->pclass;
1268                 ptag = ctx->ptag;
1269                 p += ctx->hdrlen;
1270                 }
1271         else
1272                 {
1273                 i = ASN1_get_object(&p, &plen, &ptag, &pclass, len);
1274                 if (ctx)
1275                         {
1276                         ctx->ret = i;
1277                         ctx->plen = plen;
1278                         ctx->pclass = pclass;
1279                         ctx->ptag = ptag;
1280                         ctx->hdrlen = p - q;
1281                         ctx->valid = 1;
1282                         /* If definite length, and no error, length +
1283                          * header can't exceed total amount of data available.
1284                          */
1285                         if (!(i & 0x81) && ((plen + ctx->hdrlen) > len))
1286                                 {
1287                                 ASN1err(ASN1_F_ASN1_CHECK_TLEN,
1288                                                         ASN1_R_TOO_LONG);
1289                                 asn1_tlc_clear(ctx);
1290                                 return 0;
1291                                 }
1292                         }
1293                 }
1294
1295         if (i & 0x80)
1296                 {
1297                 ASN1err(ASN1_F_ASN1_CHECK_TLEN, ASN1_R_BAD_OBJECT_HEADER);
1298                 asn1_tlc_clear(ctx);
1299                 return 0;
1300                 }
1301         if (exptag >= 0)
1302                 {
1303                 if ((exptag != ptag) || (expclass != pclass))
1304                         {
1305                         /* If type is OPTIONAL, not an error:
1306                          * indicate missing type.
1307                          */
1308                         if (opt) return -1;
1309                         asn1_tlc_clear(ctx);
1310                         ASN1err(ASN1_F_ASN1_CHECK_TLEN, ASN1_R_WRONG_TAG);
1311                         return 0;
1312                         }
1313                 /* We have a tag and class match:
1314                  * assume we are going to do something with it */
1315                 asn1_tlc_clear(ctx);
1316                 }
1317
1318         if (i & 1)
1319                 plen = len - (p - q);
1320
1321         if (inf)
1322                 *inf = i & 1;
1323
1324         if (cst)
1325                 *cst = i & V_ASN1_CONSTRUCTED;
1326
1327         if (olen)
1328                 *olen = plen;
1329
1330         if (oclass)
1331                 *oclass = pclass;
1332
1333         if (otag)
1334                 *otag = ptag;
1335
1336         *in = p;
1337         return 1;
1338         }