crypto/asn1/tasn_enc.c

   1 /*
   2  * Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the OpenSSL license (the "License").  You may not use
   5  * this file except in compliance with the License.  You can obtain a copy
   6  * in the file LICENSE in the source distribution or at
   7  * https://www.openssl.org/source/license.html
   8  */
   9
  10 #include <stddef.h>
  11 #include <string.h>
  12 #include "internal/cryptlib.h"
  13 #include <openssl/asn1.h>
  14 #include <openssl/asn1t.h>
  15 #include <openssl/objects.h>
  16 #include "internal/asn1_int.h"
  17 #include "asn1_locl.h"
  18
  19 static int asn1_i2d_ex_primitive(ASN1_VALUE **pval, unsigned char **out,
  20                                  const ASN1_ITEM *it, int tag, int aclass);
  21 static int asn1_set_seq_out(STACK_OF(ASN1_VALUE) *sk, unsigned char **out,
  22                             int skcontlen, const ASN1_ITEM *item,
  23                             int do_sort, int iclass);
  24 static int asn1_template_ex_i2d(ASN1_VALUE **pval, unsigned char **out,
  25                                 const ASN1_TEMPLATE *tt, int tag, int aclass);
  26 static int asn1_item_flags_i2d(ASN1_VALUE *val, unsigned char **out,
  27                                const ASN1_ITEM *it, int flags);
  28 static int asn1_ex_i2c(ASN1_VALUE **pval, unsigned char *cout, int *putype,
  29                        const ASN1_ITEM *it);
  30
  31 /*
  32  * Top level i2d equivalents: the 'ndef' variant instructs the encoder to use
  33  * indefinite length constructed encoding, where appropriate
  34  */
  35
  36 int ASN1_item_ndef_i2d(ASN1_VALUE *val, unsigned char **out,
  37                        const ASN1_ITEM *it)
  38 {
  39     return asn1_item_flags_i2d(val, out, it, ASN1_TFLG_NDEF);
  40 }
  41
  42 int ASN1_item_i2d(ASN1_VALUE *val, unsigned char **out, const ASN1_ITEM *it)
  43 {
  44     return asn1_item_flags_i2d(val, out, it, 0);
  45 }
  46
  47 /*
  48  * Encode an ASN1 item, this is use by the standard 'i2d' function. 'out'
  49  * points to a buffer to output the data to. The new i2d has one additional
  50  * feature. If the output buffer is NULL (i.e. *out == NULL) then a buffer is
  51  * allocated and populated with the encoding.
  52  */
  53
  54 static int asn1_item_flags_i2d(ASN1_VALUE *val, unsigned char **out,
  55                                const ASN1_ITEM *it, int flags)
  56 {
  57     if (out && !*out) {
  58         unsigned char *p, *buf;
  59         int len;
  60         len = ASN1_item_ex_i2d(&val, NULL, it, -1, flags);
  61         if (len <= 0)
  62             return len;
  63         buf = OPENSSL_malloc(len);
  64         if (buf == NULL)
  65             return -1;
  66         p = buf;
  67         ASN1_item_ex_i2d(&val, &p, it, -1, flags);
  68         *out = buf;
  69         return len;
  70     }
  71
  72     return ASN1_item_ex_i2d(&val, out, it, -1, flags);
  73 }
  74
  75 /*
  76  * Encode an item, taking care of IMPLICIT tagging (if any). This function
  77  * performs the normal item handling: it can be used in external types.
  78  */
  79
  80 int ASN1_item_ex_i2d(ASN1_VALUE **pval, unsigned char **out,
  81                      const ASN1_ITEM *it, int tag, int aclass)
  82 {
  83     const ASN1_TEMPLATE *tt = NULL;
  84     int i, seqcontlen, seqlen, ndef = 1;
  85     const ASN1_EXTERN_FUNCS *ef;
  86     const ASN1_AUX *aux = it->funcs;
  87     ASN1_aux_cb *asn1_cb = 0;
  88
  89     if ((it->itype != ASN1_ITYPE_PRIMITIVE) && !*pval)
  90         return 0;
  91
  92     if (aux && aux->asn1_cb)
  93         asn1_cb = aux->asn1_cb;
  94
  95     switch (it->itype) {
  96
  97     case ASN1_ITYPE_PRIMITIVE:
  98         if (it->templates)
  99             return asn1_template_ex_i2d(pval, out, it->templates,
 100                                         tag, aclass);
 101         return asn1_i2d_ex_primitive(pval, out, it, tag, aclass);
 102
 103     case ASN1_ITYPE_MSTRING:
 104         return asn1_i2d_ex_primitive(pval, out, it, -1, aclass);
 105
 106     case ASN1_ITYPE_CHOICE:
 107         if (asn1_cb && !asn1_cb(ASN1_OP_I2D_PRE, pval, it, NULL))
 108             return 0;
 109         i = asn1_get_choice_selector(pval, it);
 110         if ((i >= 0) && (i < it->tcount)) {
 111             ASN1_VALUE **pchval;
 112             const ASN1_TEMPLATE *chtt;
 113             chtt = it->templates + i;
 114             pchval = asn1_get_field_ptr(pval, chtt);
 115             return asn1_template_ex_i2d(pchval, out, chtt, -1, aclass);
 116         }
 117         /* Fixme: error condition if selector out of range */
 118         if (asn1_cb && !asn1_cb(ASN1_OP_I2D_POST, pval, it, NULL))
 119             return 0;
 120         break;
 121
 122     case ASN1_ITYPE_EXTERN:
 123         /* If new style i2d it does all the work */
 124         ef = it->funcs;
 125         return ef->asn1_ex_i2d(pval, out, it, tag, aclass);
 126
 127     case ASN1_ITYPE_NDEF_SEQUENCE:
 128         /* Use indefinite length constructed if requested */
 129         if (aclass & ASN1_TFLG_NDEF)
 130             ndef = 2;
 131         /* fall through */
 132
 133     case ASN1_ITYPE_SEQUENCE:
 134         i = asn1_enc_restore(&seqcontlen, out, pval, it);
 135         /* An error occurred */
 136         if (i < 0)
 137             return 0;
 138         /* We have a valid cached encoding... */
 139         if (i > 0)
 140             return seqcontlen;
 141         /* Otherwise carry on */
 142         seqcontlen = 0;
 143         /* If no IMPLICIT tagging set to SEQUENCE, UNIVERSAL */
 144         if (tag == -1) {
 145             tag = V_ASN1_SEQUENCE;
 146             /* Retain any other flags in aclass */
 147             aclass = (aclass & ~ASN1_TFLG_TAG_CLASS)
 148                 | V_ASN1_UNIVERSAL;
 149         }
 150         if (asn1_cb && !asn1_cb(ASN1_OP_I2D_PRE, pval, it, NULL))
 151             return 0;
 152         /* First work out sequence content length */
 153         for (i = 0, tt = it->templates; i < it->tcount; tt++, i++) {
 154             const ASN1_TEMPLATE *seqtt;
 155             ASN1_VALUE **pseqval;
 156             seqtt = asn1_do_adb(pval, tt, 1);
 157             if (!seqtt)
 158                 return 0;
 159             pseqval = asn1_get_field_ptr(pval, seqtt);
 160             /* FIXME: check for errors in enhanced version */
 161             seqcontlen += asn1_template_ex_i2d(pseqval, NULL, seqtt,
 162                                                -1, aclass);
 163         }
 164
 165         seqlen = ASN1_object_size(ndef, seqcontlen, tag);
 166         if (!out)
 167             return seqlen;
 168         /* Output SEQUENCE header */
 169         ASN1_put_object(out, ndef, seqcontlen, tag, aclass);
 170         for (i = 0, tt = it->templates; i < it->tcount; tt++, i++) {
 171             const ASN1_TEMPLATE *seqtt;
 172             ASN1_VALUE **pseqval;
 173             seqtt = asn1_do_adb(pval, tt, 1);
 174             if (!seqtt)
 175                 return 0;
 176             pseqval = asn1_get_field_ptr(pval, seqtt);
 177             /* FIXME: check for errors in enhanced version */
 178             asn1_template_ex_i2d(pseqval, out, seqtt, -1, aclass);
 179         }
 180         if (ndef == 2)
 181             ASN1_put_eoc(out);
 182         if (asn1_cb && !asn1_cb(ASN1_OP_I2D_POST, pval, it, NULL))
 183             return 0;
 184         return seqlen;
 185
 186     default:
 187         return 0;
 188
 189     }
 190     return 0;
 191 }
 192
 193 static int asn1_template_ex_i2d(ASN1_VALUE **pval, unsigned char **out,
 194                                 const ASN1_TEMPLATE *tt, int tag, int iclass)
 195 {
 196     int i, ret, flags, ttag, tclass, ndef;
 197     ASN1_VALUE *tval;
 198     flags = tt->flags;
 199
 200     /*
 201      * If field is embedded then val needs fixing so it is a pointer to
 202      * a pointer to a field.
 203      */
 204     if (flags & ASN1_TFLG_EMBED) {
 205         tval = (ASN1_VALUE *)pval;
 206         pval = &tval;
 207     }
 208     /*
 209      * Work out tag and class to use: tagging may come either from the
 210      * template or the arguments, not both because this would create
 211      * ambiguity. Additionally the iclass argument may contain some
 212      * additional flags which should be noted and passed down to other
 213      * levels.
 214      */
 215     if (flags & ASN1_TFLG_TAG_MASK) {
 216         /* Error if argument and template tagging */
 217         if (tag != -1)
 218             /* FIXME: error code here */
 219             return -1;
 220         /* Get tagging from template */
 221         ttag = tt->tag;
 222         tclass = flags & ASN1_TFLG_TAG_CLASS;
 223     } else if (tag != -1) {
 224         /* No template tagging, get from arguments */
 225         ttag = tag;
 226         tclass = iclass & ASN1_TFLG_TAG_CLASS;
 227     } else {
 228         ttag = -1;
 229         tclass = 0;
 230     }
 231     /*
 232      * Remove any class mask from iflag.
 233      */
 234     iclass &= ~ASN1_TFLG_TAG_CLASS;
 235
 236     /*
 237      * At this point 'ttag' contains the outer tag to use, 'tclass' is the
 238      * class and iclass is any flags passed to this function.
 239      */
 240
 241     /* if template and arguments require ndef, use it */
 242     if ((flags & ASN1_TFLG_NDEF) && (iclass & ASN1_TFLG_NDEF))
 243         ndef = 2;
 244     else
 245         ndef = 1;
 246
 247     if (flags & ASN1_TFLG_SK_MASK) {
 248         /* SET OF, SEQUENCE OF */
 249         STACK_OF(ASN1_VALUE) *sk = (STACK_OF(ASN1_VALUE) *)*pval;
 250         int isset, sktag, skaclass;
 251         int skcontlen, sklen;
 252         ASN1_VALUE *skitem;
 253
 254         if (!*pval)
 255             return 0;
 256
 257         if (flags & ASN1_TFLG_SET_OF) {
 258             isset = 1;
 259             /* 2 means we reorder */
 260             if (flags & ASN1_TFLG_SEQUENCE_OF)
 261                 isset = 2;
 262         } else
 263             isset = 0;
 264
 265         /*
 266          * Work out inner tag value: if EXPLICIT or no tagging use underlying
 267          * type.
 268          */
 269         if ((ttag != -1) && !(flags & ASN1_TFLG_EXPTAG)) {
 270             sktag = ttag;
 271             skaclass = tclass;
 272         } else {
 273             skaclass = V_ASN1_UNIVERSAL;
 274             if (isset)
 275                 sktag = V_ASN1_SET;
 276             else
 277                 sktag = V_ASN1_SEQUENCE;
 278         }
 279
 280         /* Determine total length of items */
 281         skcontlen = 0;
 282         for (i = 0; i < sk_ASN1_VALUE_num(sk); i++) {
 283             skitem = sk_ASN1_VALUE_value(sk, i);
 284             skcontlen += ASN1_item_ex_i2d(&skitem, NULL,
 285                                           ASN1_ITEM_ptr(tt->item),
 286                                           -1, iclass);
 287         }
 288         sklen = ASN1_object_size(ndef, skcontlen, sktag);
 289         /* If EXPLICIT need length of surrounding tag */
 290         if (flags & ASN1_TFLG_EXPTAG)
 291             ret = ASN1_object_size(ndef, sklen, ttag);
 292         else
 293             ret = sklen;
 294
 295         if (!out)
 296             return ret;
 297
 298         /* Now encode this lot... */
 299         /* EXPLICIT tag */
 300         if (flags & ASN1_TFLG_EXPTAG)
 301             ASN1_put_object(out, ndef, sklen, ttag, tclass);
 302         /* SET or SEQUENCE and IMPLICIT tag */
 303         ASN1_put_object(out, ndef, skcontlen, sktag, skaclass);
 304         /* And the stuff itself */
 305         asn1_set_seq_out(sk, out, skcontlen, ASN1_ITEM_ptr(tt->item),
 306                          isset, iclass);
 307         if (ndef == 2) {
 308             ASN1_put_eoc(out);
 309             if (flags & ASN1_TFLG_EXPTAG)
 310                 ASN1_put_eoc(out);
 311         }
 312
 313         return ret;
 314     }
 315
 316     if (flags & ASN1_TFLG_EXPTAG) {
 317         /* EXPLICIT tagging */
 318         /* Find length of tagged item */
 319         i = ASN1_item_ex_i2d(pval, NULL, ASN1_ITEM_ptr(tt->item), -1, iclass);
 320         if (!i)
 321             return 0;
 322         /* Find length of EXPLICIT tag */
 323         ret = ASN1_object_size(ndef, i, ttag);
 324         if (out) {
 325             /* Output tag and item */
 326             ASN1_put_object(out, ndef, i, ttag, tclass);
 327             ASN1_item_ex_i2d(pval, out, ASN1_ITEM_ptr(tt->item), -1, iclass);
 328             if (ndef == 2)
 329                 ASN1_put_eoc(out);
 330         }
 331         return ret;
 332     }
 333
 334     /* Either normal or IMPLICIT tagging: combine class and flags */
 335     return ASN1_item_ex_i2d(pval, out, ASN1_ITEM_ptr(tt->item),
 336                             ttag, tclass | iclass);
 337
 338 }
 339
 340 /* Temporary structure used to hold DER encoding of items for SET OF */
 341
 342 typedef struct {
 343     unsigned char *data;
 344     int length;
 345     ASN1_VALUE *field;
 346 } DER_ENC;
 347
 348 static int der_cmp(const void *a, const void *b)
 349 {
 350     const DER_ENC *d1 = a, *d2 = b;
 351     int cmplen, i;
 352     cmplen = (d1->length < d2->length) ? d1->length : d2->length;
 353     i = memcmp(d1->data, d2->data, cmplen);
 354     if (i)
 355         return i;
 356     return d1->length - d2->length;
 357 }
 358
 359 /* Output the content octets of SET OF or SEQUENCE OF */
 360
 361 static int asn1_set_seq_out(STACK_OF(ASN1_VALUE) *sk, unsigned char **out,
 362                             int skcontlen, const ASN1_ITEM *item,
 363                             int do_sort, int iclass)
 364 {
 365     int i;
 366     ASN1_VALUE *skitem;
 367     unsigned char *tmpdat = NULL, *p = NULL;
 368     DER_ENC *derlst = NULL, *tder;
 369     if (do_sort) {
 370         /* Don't need to sort less than 2 items */
 371         if (sk_ASN1_VALUE_num(sk) < 2)
 372             do_sort = 0;
 373         else {
 374             derlst = OPENSSL_malloc(sk_ASN1_VALUE_num(sk)
 375                                     * sizeof(*derlst));
 376             if (derlst == NULL)
 377                 return 0;
 378             tmpdat = OPENSSL_malloc(skcontlen);
 379             if (tmpdat == NULL) {
 380                 OPENSSL_free(derlst);
 381                 return 0;
 382             }
 383         }
 384     }
 385     /* If not sorting just output each item */
 386     if (!do_sort) {
 387         for (i = 0; i < sk_ASN1_VALUE_num(sk); i++) {
 388             skitem = sk_ASN1_VALUE_value(sk, i);
 389             ASN1_item_ex_i2d(&skitem, out, item, -1, iclass);
 390         }
 391         return 1;
 392     }
 393     p = tmpdat;
 394
 395     /* Doing sort: build up a list of each member's DER encoding */
 396     for (i = 0, tder = derlst; i < sk_ASN1_VALUE_num(sk); i++, tder++) {
 397         skitem = sk_ASN1_VALUE_value(sk, i);
 398         tder->data = p;
 399         tder->length = ASN1_item_ex_i2d(&skitem, &p, item, -1, iclass);
 400         tder->field = skitem;
 401     }
 402
 403     /* Now sort them */
 404     qsort(derlst, sk_ASN1_VALUE_num(sk), sizeof(*derlst), der_cmp);
 405     /* Output sorted DER encoding */
 406     p = *out;
 407     for (i = 0, tder = derlst; i < sk_ASN1_VALUE_num(sk); i++, tder++) {
 408         memcpy(p, tder->data, tder->length);
 409         p += tder->length;
 410     }
 411     *out = p;
 412     /* If do_sort is 2 then reorder the STACK */
 413     if (do_sort == 2) {
 414         for (i = 0, tder = derlst; i < sk_ASN1_VALUE_num(sk); i++, tder++)
 415             (void)sk_ASN1_VALUE_set(sk, i, tder->field);
 416     }
 417     OPENSSL_free(derlst);
 418     OPENSSL_free(tmpdat);
 419     return 1;
 420 }
 421
 422 static int asn1_i2d_ex_primitive(ASN1_VALUE **pval, unsigned char **out,
 423                                  const ASN1_ITEM *it, int tag, int aclass)
 424 {
 425     int len;
 426     int utype;
 427     int usetag;
 428     int ndef = 0;
 429
 430     utype = it->utype;
 431
 432     /*
 433      * Get length of content octets and maybe find out the underlying type.
 434      */
 435
 436     len = asn1_ex_i2c(pval, NULL, &utype, it);
 437
 438     /*
 439      * If SEQUENCE, SET or OTHER then header is included in pseudo content
 440      * octets so don't include tag+length. We need to check here because the
 441      * call to asn1_ex_i2c() could change utype.
 442      */
 443     if ((utype == V_ASN1_SEQUENCE) || (utype == V_ASN1_SET) ||
 444         (utype == V_ASN1_OTHER))
 445         usetag = 0;
 446     else
 447         usetag = 1;
 448
 449     /* -1 means omit type */
 450
 451     if (len == -1)
 452         return 0;
 453
 454     /* -2 return is special meaning use ndef */
 455     if (len == -2) {
 456         ndef = 2;
 457         len = 0;
 458     }
 459
 460     /* If not implicitly tagged get tag from underlying type */
 461     if (tag == -1)
 462         tag = utype;
 463
 464     /* Output tag+length followed by content octets */
 465     if (out) {
 466         if (usetag)
 467             ASN1_put_object(out, ndef, len, tag, aclass);
 468         asn1_ex_i2c(pval, *out, &utype, it);
 469         if (ndef)
 470             ASN1_put_eoc(out);
 471         else
 472             *out += len;
 473     }
 474
 475     if (usetag)
 476         return ASN1_object_size(ndef, len, tag);
 477     return len;
 478 }
 479
 480 /* Produce content octets from a structure */
 481
 482 static int asn1_ex_i2c(ASN1_VALUE **pval, unsigned char *cout, int *putype,
 483                        const ASN1_ITEM *it)
 484 {
 485     ASN1_BOOLEAN *tbool = NULL;
 486     ASN1_STRING *strtmp;
 487     ASN1_OBJECT *otmp;
 488     int utype;
 489     const unsigned char *cont;
 490     unsigned char c;
 491     int len;
 492     const ASN1_PRIMITIVE_FUNCS *pf;
 493     pf = it->funcs;
 494     if (pf && pf->prim_i2c)
 495         return pf->prim_i2c(pval, cout, putype, it);
 496
 497     /* Should type be omitted? */
 498     if ((it->itype != ASN1_ITYPE_PRIMITIVE)
 499         || (it->utype != V_ASN1_BOOLEAN)) {
 500         if (!*pval)
 501             return -1;
 502     }
 503
 504     if (it->itype == ASN1_ITYPE_MSTRING) {
 505         /* If MSTRING type set the underlying type */
 506         strtmp = (ASN1_STRING *)*pval;
 507         utype = strtmp->type;
 508         *putype = utype;
 509     } else if (it->utype == V_ASN1_ANY) {
 510         /* If ANY set type and pointer to value */
 511         ASN1_TYPE *typ;
 512         typ = (ASN1_TYPE *)*pval;
 513         utype = typ->type;
 514         *putype = utype;
 515         pval = &typ->value.asn1_value;
 516     } else
 517         utype = *putype;
 518
 519     switch (utype) {
 520     case V_ASN1_OBJECT:
 521         otmp = (ASN1_OBJECT *)*pval;
 522         cont = otmp->data;
 523         len = otmp->length;
 524         break;
 525
 526     case V_ASN1_NULL:
 527         cont = NULL;
 528         len = 0;
 529         break;
 530
 531     case V_ASN1_BOOLEAN:
 532         tbool = (ASN1_BOOLEAN *)pval;
 533         if (*tbool == -1)
 534             return -1;
 535         if (it->utype != V_ASN1_ANY) {
 536             /*
 537              * Default handling if value == size field then omit
 538              */
 539             if (*tbool && (it->size > 0))
 540                 return -1;
 541             if (!*tbool && !it->size)
 542                 return -1;
 543         }
 544         c = (unsigned char)*tbool;
 545         cont = &c;
 546         len = 1;
 547         break;
 548
 549     case V_ASN1_BIT_STRING:
 550         return i2c_ASN1_BIT_STRING((ASN1_BIT_STRING *)*pval,
 551                                    cout ? &cout : NULL);
 552
 553     case V_ASN1_INTEGER:
 554     case V_ASN1_ENUMERATED:
 555         /*
 556          * These are all have the same content format as ASN1_INTEGER
 557          */
 558         return i2c_ASN1_INTEGER((ASN1_INTEGER *)*pval, cout ? &cout : NULL);
 559
 560     case V_ASN1_OCTET_STRING:
 561     case V_ASN1_NUMERICSTRING:
 562     case V_ASN1_PRINTABLESTRING:
 563     case V_ASN1_T61STRING:
 564     case V_ASN1_VIDEOTEXSTRING:
 565     case V_ASN1_IA5STRING:
 566     case V_ASN1_UTCTIME:
 567     case V_ASN1_GENERALIZEDTIME:
 568     case V_ASN1_GRAPHICSTRING:
 569     case V_ASN1_VISIBLESTRING:
 570     case V_ASN1_GENERALSTRING:
 571     case V_ASN1_UNIVERSALSTRING:
 572     case V_ASN1_BMPSTRING:
 573     case V_ASN1_UTF8STRING:
 574     case V_ASN1_SEQUENCE:
 575     case V_ASN1_SET:
 576     default:
 577         /* All based on ASN1_STRING and handled the same */
 578         strtmp = (ASN1_STRING *)*pval;
 579         /* Special handling for NDEF */
 580         if ((it->size == ASN1_TFLG_NDEF)
 581             && (strtmp->flags & ASN1_STRING_FLAG_NDEF)) {
 582             if (cout) {
 583                 strtmp->data = cout;
 584                 strtmp->length = 0;
 585             }
 586             /* Special return code */
 587             return -2;
 588         }
 589         cont = strtmp->data;
 590         len = strtmp->length;
 591
 592         break;
 593
 594     }
 595     if (cout && len)
 596         memcpy(cout, cont, len);
 597     return len;
 598 }