1 /* $OpenBSD: tasn_dec.c,v 1.37.10.1 2020/12/08 15:08:47 tb Exp $ */ 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 /* Constructed types with a recursive definition (such as can be found in PKCS7) 69 * could eventually exceed the stack given malicious input with excessive 70 * recursion. Therefore we limit the stack depth. 71 */ 72 #define ASN1_MAX_CONSTRUCTED_NEST 30 73 74 static int asn1_check_eoc(const unsigned char **in, long len); 75 static int asn1_find_end(const unsigned char **in, long len, char inf); 76 77 static int asn1_collect(BUF_MEM *buf, const unsigned char **in, long len, 78 char inf, int tag, int aclass, int depth); 79 80 static int collect_data(BUF_MEM *buf, const unsigned char **p, long plen); 81 82 static int asn1_check_tlen(long *olen, int *otag, unsigned char *oclass, 83 char *inf, char *cst, const unsigned char **in, long len, int exptag, 84 int expclass, char opt, ASN1_TLC *ctx); 85 86 static int asn1_template_ex_d2i(ASN1_VALUE **pval, const unsigned char **in, 87 long len, const ASN1_TEMPLATE *tt, char opt, ASN1_TLC *ctx, int depth); 88 static int asn1_template_noexp_d2i(ASN1_VALUE **val, const unsigned char **in, 89 long len, const ASN1_TEMPLATE *tt, char opt, ASN1_TLC *ctx, int depth); 90 static int asn1_d2i_ex_primitive(ASN1_VALUE **pval, const unsigned char **in, 91 long len, const ASN1_ITEM *it, int tag, int aclass, char opt, 92 ASN1_TLC *ctx); 93 94 /* Table to convert tags to bit values, used for MSTRING type */ 95 static const unsigned long tag2bit[32] = { 96 0, 0, 0, B_ASN1_BIT_STRING, /* tags 0 - 3 */ 97 B_ASN1_OCTET_STRING, 0, 0, B_ASN1_UNKNOWN,/* tags 4- 7 */ 98 B_ASN1_UNKNOWN, B_ASN1_UNKNOWN, B_ASN1_UNKNOWN, B_ASN1_UNKNOWN,/* tags 8-11 */ 99 B_ASN1_UTF8STRING,B_ASN1_UNKNOWN,B_ASN1_UNKNOWN,B_ASN1_UNKNOWN,/* tags 12-15 */ 100 B_ASN1_SEQUENCE,0,B_ASN1_NUMERICSTRING,B_ASN1_PRINTABLESTRING, /* tags 16-19 */ 101 B_ASN1_T61STRING,B_ASN1_VIDEOTEXSTRING,B_ASN1_IA5STRING, /* tags 20-22 */ 102 B_ASN1_UTCTIME, B_ASN1_GENERALIZEDTIME, /* tags 23-24 */ 103 B_ASN1_GRAPHICSTRING,B_ASN1_ISO64STRING,B_ASN1_GENERALSTRING, /* tags 25-27 */ 104 B_ASN1_UNIVERSALSTRING,B_ASN1_UNKNOWN,B_ASN1_BMPSTRING,B_ASN1_UNKNOWN, /* tags 28-31 */ 105 }; 106 107 unsigned long 108 ASN1_tag2bit(int tag) 109 { 110 if ((tag < 0) || (tag > 30)) 111 return 0; 112 return tag2bit[tag]; 113 } 114 115 /* Macro to initialize and invalidate the cache */ 116 117 #define asn1_tlc_clear(c) if (c) (c)->valid = 0 118 /* Version to avoid compiler warning about 'c' always non-NULL */ 119 #define asn1_tlc_clear_nc(c) (c)->valid = 0 120 121 /* Decode an ASN1 item, this currently behaves just 122 * like a standard 'd2i' function. 'in' points to 123 * a buffer to read the data from, in future we will 124 * have more advanced versions that can input data 125 * a piece at a time and this will simply be a special 126 * case. 127 */ 128 129 ASN1_VALUE * 130 ASN1_item_d2i(ASN1_VALUE **pval, const unsigned char **in, long len, 131 const ASN1_ITEM *it) 132 { 133 ASN1_TLC c; 134 ASN1_VALUE *ptmpval = NULL; 135 136 if (!pval) 137 pval = &ptmpval; 138 asn1_tlc_clear_nc(&c); 139 if (ASN1_item_ex_d2i(pval, in, len, it, -1, 0, 0, &c) > 0) 140 return *pval; 141 return NULL; 142 } 143 144 int 145 ASN1_template_d2i(ASN1_VALUE **pval, const unsigned char **in, long len, 146 const ASN1_TEMPLATE *tt) 147 { 148 ASN1_TLC c; 149 150 asn1_tlc_clear_nc(&c); 151 return asn1_template_ex_d2i(pval, in, len, tt, 0, &c, 0); 152 } 153 154 155 /* Decode an item, taking care of IMPLICIT tagging, if any. 156 * If 'opt' set and tag mismatch return -1 to handle OPTIONAL 157 */ 158 159 static int 160 asn1_item_ex_d2i(ASN1_VALUE **pval, const unsigned char **in, long len, 161 const ASN1_ITEM *it, int tag, int aclass, char opt, ASN1_TLC *ctx, 162 int depth) 163 { 164 const ASN1_TEMPLATE *tt, *errtt = NULL; 165 const ASN1_EXTERN_FUNCS *ef; 166 const ASN1_AUX *aux = it->funcs; 167 ASN1_aux_cb *asn1_cb = NULL; 168 const unsigned char *p = NULL, *q; 169 unsigned char oclass; 170 char seq_eoc, seq_nolen, cst, isopt; 171 long tmplen; 172 int i; 173 int otag; 174 int ret = 0; 175 ASN1_VALUE **pchptr; 176 int combine; 177 178 combine = aclass & ASN1_TFLG_COMBINE; 179 aclass &= ~ASN1_TFLG_COMBINE; 180 181 if (!pval) 182 return 0; 183 184 if (aux && aux->asn1_cb) 185 asn1_cb = aux->asn1_cb; 186 187 if (++depth > ASN1_MAX_CONSTRUCTED_NEST) { 188 ASN1error(ASN1_R_NESTED_TOO_DEEP); 189 goto err; 190 } 191 192 switch (it->itype) { 193 case ASN1_ITYPE_PRIMITIVE: 194 if (it->templates) { 195 /* tagging or OPTIONAL is currently illegal on an item 196 * template because the flags can't get passed down. 197 * In practice this isn't a problem: we include the 198 * relevant flags from the item template in the 199 * template itself. 200 */ 201 if ((tag != -1) || opt) { 202 ASN1error(ASN1_R_ILLEGAL_OPTIONS_ON_ITEM_TEMPLATE); 203 goto err; 204 } 205 return asn1_template_ex_d2i(pval, in, len, 206 it->templates, opt, ctx, depth); 207 } 208 return asn1_d2i_ex_primitive(pval, in, len, it, 209 tag, aclass, opt, ctx); 210 break; 211 212 case ASN1_ITYPE_MSTRING: 213 /* 214 * It never makes sense for multi-strings to have implicit 215 * tagging, so if tag != -1, then this looks like an error in 216 * the template. 217 */ 218 if (tag != -1) { 219 ASN1error(ASN1_R_BAD_TEMPLATE); 220 goto err; 221 } 222 223 p = *in; 224 /* Just read in tag and class */ 225 ret = asn1_check_tlen(NULL, &otag, &oclass, NULL, NULL, 226 &p, len, -1, 0, 1, ctx); 227 if (!ret) { 228 ASN1error(ERR_R_NESTED_ASN1_ERROR); 229 goto err; 230 } 231 232 /* Must be UNIVERSAL class */ 233 if (oclass != V_ASN1_UNIVERSAL) { 234 /* If OPTIONAL, assume this is OK */ 235 if (opt) 236 return -1; 237 ASN1error(ASN1_R_MSTRING_NOT_UNIVERSAL); 238 goto err; 239 } 240 /* Check tag matches bit map */ 241 if (!(ASN1_tag2bit(otag) & it->utype)) { 242 /* If OPTIONAL, assume this is OK */ 243 if (opt) 244 return -1; 245 ASN1error(ASN1_R_MSTRING_WRONG_TAG); 246 goto err; 247 } 248 return asn1_d2i_ex_primitive(pval, in, len, 249 it, otag, 0, 0, ctx); 250 251 case ASN1_ITYPE_EXTERN: 252 /* Use new style d2i */ 253 ef = it->funcs; 254 return ef->asn1_ex_d2i(pval, in, len, 255 it, tag, aclass, opt, ctx); 256 257 case ASN1_ITYPE_CHOICE: 258 /* 259 * It never makes sense for CHOICE types to have implicit 260 * tagging, so if tag != -1, then this looks like an error in 261 * the template. 262 */ 263 if (tag != -1) { 264 ASN1error(ASN1_R_BAD_TEMPLATE); 265 goto err; 266 } 267 268 if (asn1_cb && !asn1_cb(ASN1_OP_D2I_PRE, pval, it, NULL)) 269 goto auxerr; 270 271 if (*pval) { 272 /* Free up and zero CHOICE value if initialised */ 273 i = asn1_get_choice_selector(pval, it); 274 if ((i >= 0) && (i < it->tcount)) { 275 tt = it->templates + i; 276 pchptr = asn1_get_field_ptr(pval, tt); 277 ASN1_template_free(pchptr, tt); 278 asn1_set_choice_selector(pval, -1, it); 279 } 280 } else if (!ASN1_item_ex_new(pval, it)) { 281 ASN1error(ERR_R_NESTED_ASN1_ERROR); 282 goto err; 283 } 284 /* CHOICE type, try each possibility in turn */ 285 p = *in; 286 for (i = 0, tt = it->templates; i < it->tcount; i++, tt++) { 287 pchptr = asn1_get_field_ptr(pval, tt); 288 /* We mark field as OPTIONAL so its absence 289 * can be recognised. 290 */ 291 ret = asn1_template_ex_d2i(pchptr, &p, len, tt, 1, ctx, 292 depth); 293 /* If field not present, try the next one */ 294 if (ret == -1) 295 continue; 296 /* If positive return, read OK, break loop */ 297 if (ret > 0) 298 break; 299 /* Otherwise must be an ASN1 parsing error */ 300 errtt = tt; 301 ASN1error(ERR_R_NESTED_ASN1_ERROR); 302 goto err; 303 } 304 305 /* Did we fall off the end without reading anything? */ 306 if (i == it->tcount) { 307 /* If OPTIONAL, this is OK */ 308 if (opt) { 309 /* Free and zero it */ 310 ASN1_item_ex_free(pval, it); 311 return -1; 312 } 313 ASN1error(ASN1_R_NO_MATCHING_CHOICE_TYPE); 314 goto err; 315 } 316 317 asn1_set_choice_selector(pval, i, it); 318 *in = p; 319 if (asn1_cb && !asn1_cb(ASN1_OP_D2I_POST, pval, it, NULL)) 320 goto auxerr; 321 return 1; 322 323 case ASN1_ITYPE_NDEF_SEQUENCE: 324 case ASN1_ITYPE_SEQUENCE: 325 p = *in; 326 tmplen = len; 327 328 /* If no IMPLICIT tagging set to SEQUENCE, UNIVERSAL */ 329 if (tag == -1) { 330 tag = V_ASN1_SEQUENCE; 331 aclass = V_ASN1_UNIVERSAL; 332 } 333 /* Get SEQUENCE length and update len, p */ 334 ret = asn1_check_tlen(&len, NULL, NULL, &seq_eoc, &cst, 335 &p, len, tag, aclass, opt, ctx); 336 if (!ret) { 337 ASN1error(ERR_R_NESTED_ASN1_ERROR); 338 goto err; 339 } else if (ret == -1) 340 return -1; 341 if (aux && (aux->flags & ASN1_AFLG_BROKEN)) { 342 len = tmplen - (p - *in); 343 seq_nolen = 1; 344 } 345 /* If indefinite we don't do a length check */ 346 else 347 seq_nolen = seq_eoc; 348 if (!cst) { 349 ASN1error(ASN1_R_SEQUENCE_NOT_CONSTRUCTED); 350 goto err; 351 } 352 353 if (!*pval && !ASN1_item_ex_new(pval, it)) { 354 ASN1error(ERR_R_NESTED_ASN1_ERROR); 355 goto err; 356 } 357 358 if (asn1_cb && !asn1_cb(ASN1_OP_D2I_PRE, pval, it, NULL)) 359 goto auxerr; 360 361 /* Free up and zero any ADB found */ 362 for (i = 0, tt = it->templates; i < it->tcount; i++, tt++) { 363 if (tt->flags & ASN1_TFLG_ADB_MASK) { 364 const ASN1_TEMPLATE *seqtt; 365 ASN1_VALUE **pseqval; 366 seqtt = asn1_do_adb(pval, tt, 1); 367 if (!seqtt) 368 goto err; 369 pseqval = asn1_get_field_ptr(pval, seqtt); 370 ASN1_template_free(pseqval, seqtt); 371 } 372 } 373 374 /* Get each field entry */ 375 for (i = 0, tt = it->templates; i < it->tcount; i++, tt++) { 376 const ASN1_TEMPLATE *seqtt; 377 ASN1_VALUE **pseqval; 378 seqtt = asn1_do_adb(pval, tt, 1); 379 if (!seqtt) 380 goto err; 381 pseqval = asn1_get_field_ptr(pval, seqtt); 382 /* Have we ran out of data? */ 383 if (!len) 384 break; 385 q = p; 386 if (asn1_check_eoc(&p, len)) { 387 if (!seq_eoc) { 388 ASN1error(ASN1_R_UNEXPECTED_EOC); 389 goto err; 390 } 391 len -= p - q; 392 seq_eoc = 0; 393 q = p; 394 break; 395 } 396 /* This determines the OPTIONAL flag value. The field 397 * cannot be omitted if it is the last of a SEQUENCE 398 * and there is still data to be read. This isn't 399 * strictly necessary but it increases efficiency in 400 * some cases. 401 */ 402 if (i == (it->tcount - 1)) 403 isopt = 0; 404 else 405 isopt = (char)(seqtt->flags & ASN1_TFLG_OPTIONAL); 406 /* attempt to read in field, allowing each to be 407 * OPTIONAL */ 408 409 ret = asn1_template_ex_d2i(pseqval, &p, len, 410 seqtt, isopt, ctx, depth); 411 if (!ret) { 412 errtt = seqtt; 413 goto err; 414 } else if (ret == -1) { 415 /* OPTIONAL component absent. 416 * Free and zero the field. 417 */ 418 ASN1_template_free(pseqval, seqtt); 419 continue; 420 } 421 /* Update length */ 422 len -= p - q; 423 } 424 425 /* Check for EOC if expecting one */ 426 if (seq_eoc && !asn1_check_eoc(&p, len)) { 427 ASN1error(ASN1_R_MISSING_EOC); 428 goto err; 429 } 430 /* Check all data read */ 431 if (!seq_nolen && len) { 432 ASN1error(ASN1_R_SEQUENCE_LENGTH_MISMATCH); 433 goto err; 434 } 435 436 /* If we get here we've got no more data in the SEQUENCE, 437 * however we may not have read all fields so check all 438 * remaining are OPTIONAL and clear any that are. 439 */ 440 for (; i < it->tcount; tt++, i++) { 441 const ASN1_TEMPLATE *seqtt; 442 seqtt = asn1_do_adb(pval, tt, 1); 443 if (!seqtt) 444 goto err; 445 if (seqtt->flags & ASN1_TFLG_OPTIONAL) { 446 ASN1_VALUE **pseqval; 447 pseqval = asn1_get_field_ptr(pval, seqtt); 448 ASN1_template_free(pseqval, seqtt); 449 } else { 450 errtt = seqtt; 451 ASN1error(ASN1_R_FIELD_MISSING); 452 goto err; 453 } 454 } 455 /* Save encoding */ 456 if (!asn1_enc_save(pval, *in, p - *in, it)) { 457 ASN1error(ERR_R_MALLOC_FAILURE); 458 goto auxerr; 459 } 460 *in = p; 461 if (asn1_cb && !asn1_cb(ASN1_OP_D2I_POST, pval, it, NULL)) 462 goto auxerr; 463 return 1; 464 465 default: 466 return 0; 467 } 468 469 auxerr: 470 ASN1error(ASN1_R_AUX_ERROR); 471 err: 472 if (combine == 0) 473 ASN1_item_ex_free(pval, it); 474 if (errtt) 475 ERR_asprintf_error_data("Field=%s, Type=%s", errtt->field_name, 476 it->sname); 477 else 478 ERR_asprintf_error_data("Type=%s", it->sname); 479 return 0; 480 } 481 482 int 483 ASN1_item_ex_d2i(ASN1_VALUE **pval, const unsigned char **in, long len, 484 const ASN1_ITEM *it, int tag, int aclass, char opt, ASN1_TLC *ctx) 485 { 486 return asn1_item_ex_d2i(pval, in, len, it, tag, aclass, opt, ctx, 0); 487 } 488 489 /* Templates are handled with two separate functions. 490 * One handles any EXPLICIT tag and the other handles the rest. 491 */ 492 493 static int 494 asn1_template_ex_d2i(ASN1_VALUE **val, const unsigned char **in, long inlen, 495 const ASN1_TEMPLATE *tt, char opt, ASN1_TLC *ctx, int depth) 496 { 497 int flags, aclass; 498 int ret; 499 long len; 500 const unsigned char *p, *q; 501 char exp_eoc; 502 503 if (!val) 504 return 0; 505 flags = tt->flags; 506 aclass = flags & ASN1_TFLG_TAG_CLASS; 507 508 p = *in; 509 510 /* Check if EXPLICIT tag expected */ 511 if (flags & ASN1_TFLG_EXPTAG) { 512 char cst; 513 /* Need to work out amount of data available to the inner 514 * content and where it starts: so read in EXPLICIT header to 515 * get the info. 516 */ 517 ret = asn1_check_tlen(&len, NULL, NULL, &exp_eoc, &cst, 518 &p, inlen, tt->tag, aclass, opt, ctx); 519 q = p; 520 if (!ret) { 521 ASN1error(ERR_R_NESTED_ASN1_ERROR); 522 return 0; 523 } else if (ret == -1) 524 return -1; 525 if (!cst) { 526 ASN1error(ASN1_R_EXPLICIT_TAG_NOT_CONSTRUCTED); 527 return 0; 528 } 529 /* We've found the field so it can't be OPTIONAL now */ 530 ret = asn1_template_noexp_d2i(val, &p, len, tt, 0, ctx, depth); 531 if (!ret) { 532 ASN1error(ERR_R_NESTED_ASN1_ERROR); 533 return 0; 534 } 535 /* We read the field in OK so update length */ 536 len -= p - q; 537 if (exp_eoc) { 538 /* If NDEF we must have an EOC here */ 539 if (!asn1_check_eoc(&p, len)) { 540 ASN1error(ASN1_R_MISSING_EOC); 541 goto err; 542 } 543 } else { 544 /* Otherwise we must hit the EXPLICIT tag end or its 545 * an error */ 546 if (len) { 547 ASN1error(ASN1_R_EXPLICIT_LENGTH_MISMATCH); 548 goto err; 549 } 550 } 551 } else 552 return asn1_template_noexp_d2i(val, in, inlen, tt, opt, ctx, 553 depth); 554 555 *in = p; 556 return 1; 557 558 err: 559 ASN1_template_free(val, tt); 560 return 0; 561 } 562 563 static int 564 asn1_template_noexp_d2i(ASN1_VALUE **val, const unsigned char **in, long len, 565 const ASN1_TEMPLATE *tt, char opt, ASN1_TLC *ctx, int depth) 566 { 567 int flags, aclass; 568 int ret; 569 const unsigned char *p, *q; 570 571 if (!val) 572 return 0; 573 flags = tt->flags; 574 aclass = flags & ASN1_TFLG_TAG_CLASS; 575 576 p = *in; 577 q = p; 578 579 if (flags & ASN1_TFLG_SK_MASK) { 580 /* SET OF, SEQUENCE OF */ 581 int sktag, skaclass; 582 char sk_eoc; 583 /* First work out expected inner tag value */ 584 if (flags & ASN1_TFLG_IMPTAG) { 585 sktag = tt->tag; 586 skaclass = aclass; 587 } else { 588 skaclass = V_ASN1_UNIVERSAL; 589 if (flags & ASN1_TFLG_SET_OF) 590 sktag = V_ASN1_SET; 591 else 592 sktag = V_ASN1_SEQUENCE; 593 } 594 /* Get the tag */ 595 ret = asn1_check_tlen(&len, NULL, NULL, &sk_eoc, NULL, 596 &p, len, sktag, skaclass, opt, ctx); 597 if (!ret) { 598 ASN1error(ERR_R_NESTED_ASN1_ERROR); 599 return 0; 600 } else if (ret == -1) 601 return -1; 602 if (!*val) 603 *val = (ASN1_VALUE *)sk_new_null(); 604 else { 605 /* We've got a valid STACK: free up any items present */ 606 STACK_OF(ASN1_VALUE) *sktmp = 607 (STACK_OF(ASN1_VALUE) *)*val; 608 ASN1_VALUE *vtmp; 609 while (sk_ASN1_VALUE_num(sktmp) > 0) { 610 vtmp = sk_ASN1_VALUE_pop(sktmp); 611 ASN1_item_ex_free(&vtmp, 612 tt->item); 613 } 614 } 615 616 if (!*val) { 617 ASN1error(ERR_R_MALLOC_FAILURE); 618 goto err; 619 } 620 621 /* Read as many items as we can */ 622 while (len > 0) { 623 ASN1_VALUE *skfield; 624 q = p; 625 /* See if EOC found */ 626 if (asn1_check_eoc(&p, len)) { 627 if (!sk_eoc) { 628 ASN1error(ASN1_R_UNEXPECTED_EOC); 629 goto err; 630 } 631 len -= p - q; 632 sk_eoc = 0; 633 break; 634 } 635 skfield = NULL; 636 if (!asn1_item_ex_d2i(&skfield, &p, len, 637 tt->item, -1, 0, 0, ctx, depth)) { 638 ASN1error(ERR_R_NESTED_ASN1_ERROR); 639 goto err; 640 } 641 len -= p - q; 642 if (!sk_ASN1_VALUE_push((STACK_OF(ASN1_VALUE) *)*val, 643 skfield)) { 644 ASN1error(ERR_R_MALLOC_FAILURE); 645 goto err; 646 } 647 } 648 if (sk_eoc) { 649 ASN1error(ASN1_R_MISSING_EOC); 650 goto err; 651 } 652 } else if (flags & ASN1_TFLG_IMPTAG) { 653 /* IMPLICIT tagging */ 654 ret = asn1_item_ex_d2i(val, &p, len, 655 tt->item, tt->tag, aclass, opt, ctx, depth); 656 if (!ret) { 657 ASN1error(ERR_R_NESTED_ASN1_ERROR); 658 goto err; 659 } else if (ret == -1) 660 return -1; 661 } else { 662 /* Nothing special */ 663 ret = asn1_item_ex_d2i(val, &p, len, tt->item, 664 -1, tt->flags & ASN1_TFLG_COMBINE, opt, ctx, depth); 665 if (!ret) { 666 ASN1error(ERR_R_NESTED_ASN1_ERROR); 667 goto err; 668 } else if (ret == -1) 669 return -1; 670 } 671 672 *in = p; 673 return 1; 674 675 err: 676 ASN1_template_free(val, tt); 677 return 0; 678 } 679 680 static int 681 asn1_d2i_ex_primitive(ASN1_VALUE **pval, const unsigned char **in, long inlen, 682 const ASN1_ITEM *it, int tag, int aclass, char opt, ASN1_TLC *ctx) 683 { 684 int ret = 0, utype; 685 long plen; 686 char cst, inf, free_cont = 0; 687 const unsigned char *p; 688 BUF_MEM buf; 689 const unsigned char *cont = NULL; 690 long len; 691 692 buf.length = 0; 693 buf.max = 0; 694 buf.data = NULL; 695 696 if (!pval) { 697 ASN1error(ASN1_R_ILLEGAL_NULL); 698 return 0; /* Should never happen */ 699 } 700 701 if (it->itype == ASN1_ITYPE_MSTRING) { 702 utype = tag; 703 tag = -1; 704 } else 705 utype = it->utype; 706 707 if (utype == V_ASN1_ANY) { 708 /* If type is ANY need to figure out type from tag */ 709 unsigned char oclass; 710 if (tag >= 0) { 711 ASN1error(ASN1_R_ILLEGAL_TAGGED_ANY); 712 return 0; 713 } 714 if (opt) { 715 ASN1error(ASN1_R_ILLEGAL_OPTIONAL_ANY); 716 return 0; 717 } 718 p = *in; 719 ret = asn1_check_tlen(NULL, &utype, &oclass, NULL, NULL, 720 &p, inlen, -1, 0, 0, ctx); 721 if (!ret) { 722 ASN1error(ERR_R_NESTED_ASN1_ERROR); 723 return 0; 724 } 725 if (oclass != V_ASN1_UNIVERSAL) 726 utype = V_ASN1_OTHER; 727 } 728 if (tag == -1) { 729 tag = utype; 730 aclass = V_ASN1_UNIVERSAL; 731 } 732 p = *in; 733 /* Check header */ 734 ret = asn1_check_tlen(&plen, NULL, NULL, &inf, &cst, 735 &p, inlen, tag, aclass, opt, ctx); 736 if (!ret) { 737 ASN1error(ERR_R_NESTED_ASN1_ERROR); 738 return 0; 739 } else if (ret == -1) 740 return -1; 741 ret = 0; 742 /* SEQUENCE, SET and "OTHER" are left in encoded form */ 743 if ((utype == V_ASN1_SEQUENCE) || (utype == V_ASN1_SET) || 744 (utype == V_ASN1_OTHER)) { 745 /* Clear context cache for type OTHER because the auto clear 746 * when we have a exact match wont work 747 */ 748 if (utype == V_ASN1_OTHER) { 749 asn1_tlc_clear(ctx); 750 } 751 /* SEQUENCE and SET must be constructed */ 752 else if (!cst) { 753 ASN1error(ASN1_R_TYPE_NOT_CONSTRUCTED); 754 return 0; 755 } 756 757 cont = *in; 758 /* If indefinite length constructed find the real end */ 759 if (inf) { 760 if (!asn1_find_end(&p, plen, inf)) 761 goto err; 762 len = p - cont; 763 } else { 764 len = p - cont + plen; 765 p += plen; 766 buf.data = NULL; 767 } 768 } else if (cst) { 769 /* Should really check the internal tags are correct but 770 * some things may get this wrong. The relevant specs 771 * say that constructed string types should be OCTET STRINGs 772 * internally irrespective of the type. So instead just check 773 * for UNIVERSAL class and ignore the tag. 774 */ 775 if (!asn1_collect(&buf, &p, plen, inf, -1, V_ASN1_UNIVERSAL, 0)) { 776 free_cont = 1; 777 goto err; 778 } 779 len = buf.length; 780 /* Append a final null to string */ 781 if (!BUF_MEM_grow_clean(&buf, len + 1)) { 782 ASN1error(ERR_R_MALLOC_FAILURE); 783 return 0; 784 } 785 buf.data[len] = 0; 786 cont = (const unsigned char *)buf.data; 787 free_cont = 1; 788 } else { 789 cont = p; 790 len = plen; 791 p += plen; 792 } 793 794 /* We now have content length and type: translate into a structure */ 795 if (!asn1_ex_c2i(pval, cont, len, utype, &free_cont, it)) 796 goto err; 797 798 *in = p; 799 ret = 1; 800 801 err: 802 if (free_cont && buf.data) 803 free(buf.data); 804 return ret; 805 } 806 807 /* Translate ASN1 content octets into a structure */ 808 809 int 810 asn1_ex_c2i(ASN1_VALUE **pval, const unsigned char *cont, int len, int utype, 811 char *free_cont, const ASN1_ITEM *it) 812 { 813 ASN1_VALUE **opval = NULL; 814 ASN1_STRING *stmp; 815 ASN1_TYPE *typ = NULL; 816 ASN1_INTEGER **tint; 817 int ret = 0; 818 819 if (it->funcs != NULL) { 820 const ASN1_PRIMITIVE_FUNCS *pf = it->funcs; 821 822 if (pf->prim_c2i == NULL) 823 return 0; 824 return pf->prim_c2i(pval, cont, len, utype, free_cont, it); 825 } 826 827 /* If ANY type clear type and set pointer to internal value */ 828 if (it->utype == V_ASN1_ANY) { 829 if (!*pval) { 830 typ = ASN1_TYPE_new(); 831 if (typ == NULL) 832 goto err; 833 *pval = (ASN1_VALUE *)typ; 834 } else 835 typ = (ASN1_TYPE *)*pval; 836 837 if (utype != typ->type) 838 ASN1_TYPE_set(typ, utype, NULL); 839 opval = pval; 840 pval = &typ->value.asn1_value; 841 } 842 switch (utype) { 843 case V_ASN1_OBJECT: 844 if (!c2i_ASN1_OBJECT((ASN1_OBJECT **)pval, &cont, len)) 845 goto err; 846 break; 847 848 case V_ASN1_NULL: 849 if (len) { 850 ASN1error(ASN1_R_NULL_IS_WRONG_LENGTH); 851 goto err; 852 } 853 *pval = (ASN1_VALUE *)1; 854 break; 855 856 case V_ASN1_BOOLEAN: 857 if (len != 1) { 858 ASN1error(ASN1_R_BOOLEAN_IS_WRONG_LENGTH); 859 goto err; 860 } else { 861 ASN1_BOOLEAN *tbool; 862 tbool = (ASN1_BOOLEAN *)pval; 863 *tbool = *cont; 864 } 865 break; 866 867 case V_ASN1_BIT_STRING: 868 if (!c2i_ASN1_BIT_STRING((ASN1_BIT_STRING **)pval, &cont, len)) 869 goto err; 870 break; 871 872 case V_ASN1_INTEGER: 873 case V_ASN1_ENUMERATED: 874 tint = (ASN1_INTEGER **)pval; 875 if (!c2i_ASN1_INTEGER(tint, &cont, len)) 876 goto err; 877 /* Fixup type to match the expected form */ 878 (*tint)->type = utype | ((*tint)->type & V_ASN1_NEG); 879 break; 880 881 case V_ASN1_OCTET_STRING: 882 case V_ASN1_NUMERICSTRING: 883 case V_ASN1_PRINTABLESTRING: 884 case V_ASN1_T61STRING: 885 case V_ASN1_VIDEOTEXSTRING: 886 case V_ASN1_IA5STRING: 887 case V_ASN1_UTCTIME: 888 case V_ASN1_GENERALIZEDTIME: 889 case V_ASN1_GRAPHICSTRING: 890 case V_ASN1_VISIBLESTRING: 891 case V_ASN1_GENERALSTRING: 892 case V_ASN1_UNIVERSALSTRING: 893 case V_ASN1_BMPSTRING: 894 case V_ASN1_UTF8STRING: 895 case V_ASN1_OTHER: 896 case V_ASN1_SET: 897 case V_ASN1_SEQUENCE: 898 default: 899 if (utype == V_ASN1_BMPSTRING && (len & 1)) { 900 ASN1error(ASN1_R_BMPSTRING_IS_WRONG_LENGTH); 901 goto err; 902 } 903 if (utype == V_ASN1_UNIVERSALSTRING && (len & 3)) { 904 ASN1error(ASN1_R_UNIVERSALSTRING_IS_WRONG_LENGTH); 905 goto err; 906 } 907 /* All based on ASN1_STRING and handled the same */ 908 if (!*pval) { 909 stmp = ASN1_STRING_type_new(utype); 910 if (!stmp) { 911 ASN1error(ERR_R_MALLOC_FAILURE); 912 goto err; 913 } 914 *pval = (ASN1_VALUE *)stmp; 915 } else { 916 stmp = (ASN1_STRING *)*pval; 917 stmp->type = utype; 918 } 919 /* If we've already allocated a buffer use it */ 920 if (*free_cont) { 921 free(stmp->data); 922 stmp->data = (unsigned char *)cont; /* UGLY CAST! RL */ 923 stmp->length = len; 924 *free_cont = 0; 925 } else { 926 if (!ASN1_STRING_set(stmp, cont, len)) { 927 ASN1error(ERR_R_MALLOC_FAILURE); 928 ASN1_STRING_free(stmp); 929 *pval = NULL; 930 goto err; 931 } 932 } 933 break; 934 } 935 /* If ASN1_ANY and NULL type fix up value */ 936 if (typ && (utype == V_ASN1_NULL)) 937 typ->value.ptr = NULL; 938 939 ret = 1; 940 941 err: 942 if (!ret) { 943 ASN1_TYPE_free(typ); 944 if (opval) 945 *opval = NULL; 946 } 947 return ret; 948 } 949 950 951 /* This function finds the end of an ASN1 structure when passed its maximum 952 * length, whether it is indefinite length and a pointer to the content. 953 * This is more efficient than calling asn1_collect because it does not 954 * recurse on each indefinite length header. 955 */ 956 957 static int 958 asn1_find_end(const unsigned char **in, long len, char inf) 959 { 960 int expected_eoc; 961 long plen; 962 const unsigned char *p = *in, *q; 963 964 /* If not indefinite length constructed just add length */ 965 if (inf == 0) { 966 *in += len; 967 return 1; 968 } 969 expected_eoc = 1; 970 /* Indefinite length constructed form. Find the end when enough EOCs 971 * are found. If more indefinite length constructed headers 972 * are encountered increment the expected eoc count otherwise just 973 * skip to the end of the data. 974 */ 975 while (len > 0) { 976 if (asn1_check_eoc(&p, len)) { 977 expected_eoc--; 978 if (expected_eoc == 0) 979 break; 980 len -= 2; 981 continue; 982 } 983 q = p; 984 /* Just read in a header: only care about the length */ 985 if (!asn1_check_tlen(&plen, NULL, NULL, &inf, NULL, &p, len, 986 -1, 0, 0, NULL)) { 987 ASN1error(ERR_R_NESTED_ASN1_ERROR); 988 return 0; 989 } 990 if (inf) 991 expected_eoc++; 992 else 993 p += plen; 994 len -= p - q; 995 } 996 if (expected_eoc) { 997 ASN1error(ASN1_R_MISSING_EOC); 998 return 0; 999 } 1000 *in = p; 1001 return 1; 1002 } 1003 /* This function collects the asn1 data from a constructred string 1004 * type into a buffer. The values of 'in' and 'len' should refer 1005 * to the contents of the constructed type and 'inf' should be set 1006 * if it is indefinite length. 1007 */ 1008 1009 #ifndef ASN1_MAX_STRING_NEST 1010 /* This determines how many levels of recursion are permitted in ASN1 1011 * string types. If it is not limited stack overflows can occur. If set 1012 * to zero no recursion is allowed at all. Although zero should be adequate 1013 * examples exist that require a value of 1. So 5 should be more than enough. 1014 */ 1015 #define ASN1_MAX_STRING_NEST 5 1016 #endif 1017 1018 static int 1019 asn1_collect(BUF_MEM *buf, const unsigned char **in, long len, char inf, 1020 int tag, int aclass, int depth) 1021 { 1022 const unsigned char *p, *q; 1023 long plen; 1024 char cst, ininf; 1025 1026 p = *in; 1027 inf &= 1; 1028 /* If no buffer and not indefinite length constructed just pass over 1029 * the encoded data */ 1030 if (!buf && !inf) { 1031 *in += len; 1032 return 1; 1033 } 1034 while (len > 0) { 1035 q = p; 1036 /* Check for EOC */ 1037 if (asn1_check_eoc(&p, len)) { 1038 /* EOC is illegal outside indefinite length 1039 * constructed form */ 1040 if (!inf) { 1041 ASN1error(ASN1_R_UNEXPECTED_EOC); 1042 return 0; 1043 } 1044 inf = 0; 1045 break; 1046 } 1047 1048 if (!asn1_check_tlen(&plen, NULL, NULL, &ininf, &cst, &p, 1049 len, tag, aclass, 0, NULL)) { 1050 ASN1error(ERR_R_NESTED_ASN1_ERROR); 1051 return 0; 1052 } 1053 1054 /* If indefinite length constructed update max length */ 1055 if (cst) { 1056 if (depth >= ASN1_MAX_STRING_NEST) { 1057 ASN1error(ASN1_R_NESTED_ASN1_STRING); 1058 return 0; 1059 } 1060 if (!asn1_collect(buf, &p, plen, ininf, tag, aclass, 1061 depth + 1)) 1062 return 0; 1063 } else if (plen && !collect_data(buf, &p, plen)) 1064 return 0; 1065 len -= p - q; 1066 } 1067 if (inf) { 1068 ASN1error(ASN1_R_MISSING_EOC); 1069 return 0; 1070 } 1071 *in = p; 1072 return 1; 1073 } 1074 1075 static int 1076 collect_data(BUF_MEM *buf, const unsigned char **p, long plen) 1077 { 1078 int len; 1079 if (buf) { 1080 len = buf->length; 1081 if (!BUF_MEM_grow_clean(buf, len + plen)) { 1082 ASN1error(ERR_R_MALLOC_FAILURE); 1083 return 0; 1084 } 1085 memcpy(buf->data + len, *p, plen); 1086 } 1087 *p += plen; 1088 return 1; 1089 } 1090 1091 /* Check for ASN1 EOC and swallow it if found */ 1092 1093 static int 1094 asn1_check_eoc(const unsigned char **in, long len) 1095 { 1096 const unsigned char *p; 1097 1098 if (len < 2) 1099 return 0; 1100 p = *in; 1101 if (!p[0] && !p[1]) { 1102 *in += 2; 1103 return 1; 1104 } 1105 return 0; 1106 } 1107 1108 /* Check an ASN1 tag and length: a bit like ASN1_get_object 1109 * but it sets the length for indefinite length constructed 1110 * form, we don't know the exact length but we can set an 1111 * upper bound to the amount of data available minus the 1112 * header length just read. 1113 */ 1114 1115 static int 1116 asn1_check_tlen(long *olen, int *otag, unsigned char *oclass, char *inf, 1117 char *cst, const unsigned char **in, long len, int exptag, int expclass, 1118 char opt, ASN1_TLC *ctx) 1119 { 1120 int i; 1121 int ptag, pclass; 1122 long plen; 1123 const unsigned char *p, *q; 1124 1125 p = *in; 1126 q = p; 1127 1128 if (ctx && ctx->valid) { 1129 i = ctx->ret; 1130 plen = ctx->plen; 1131 pclass = ctx->pclass; 1132 ptag = ctx->ptag; 1133 p += ctx->hdrlen; 1134 } else { 1135 i = ASN1_get_object(&p, &plen, &ptag, &pclass, len); 1136 if (ctx) { 1137 ctx->ret = i; 1138 ctx->plen = plen; 1139 ctx->pclass = pclass; 1140 ctx->ptag = ptag; 1141 ctx->hdrlen = p - q; 1142 ctx->valid = 1; 1143 /* If definite length, and no error, length + 1144 * header can't exceed total amount of data available. 1145 */ 1146 if (!(i & 0x81) && ((plen + ctx->hdrlen) > len)) { 1147 ASN1error(ASN1_R_TOO_LONG); 1148 asn1_tlc_clear(ctx); 1149 return 0; 1150 } 1151 } 1152 } 1153 1154 if (i & 0x80) { 1155 ASN1error(ASN1_R_BAD_OBJECT_HEADER); 1156 asn1_tlc_clear(ctx); 1157 return 0; 1158 } 1159 if (exptag >= 0) { 1160 if ((exptag != ptag) || (expclass != pclass)) { 1161 /* If type is OPTIONAL, not an error: 1162 * indicate missing type. 1163 */ 1164 if (opt) 1165 return -1; 1166 asn1_tlc_clear(ctx); 1167 ASN1error(ASN1_R_WRONG_TAG); 1168 return 0; 1169 } 1170 /* We have a tag and class match: 1171 * assume we are going to do something with it */ 1172 asn1_tlc_clear(ctx); 1173 } 1174 1175 if (i & 1) 1176 plen = len - (p - q); 1177 if (inf) 1178 *inf = i & 1; 1179 if (cst) 1180 *cst = i & V_ASN1_CONSTRUCTED; 1181 if (olen) 1182 *olen = plen; 1183 if (oclass) 1184 *oclass = pclass; 1185 if (otag) 1186 *otag = ptag; 1187 1188 *in = p; 1189 return 1; 1190 } 1191