crypto/asn1/tasn_enc.c

   1 /*
   2  * Copyright 2000-2018 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the Apache License 2.0 (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 "crypto/asn1.h"
  17 #include "asn1_local.h"
  18
  19 static int asn1_i2d_ex_primitive(const ASN1_VALUE **pval, unsigned char **out,
  20                                  const ASN1_ITEM *it, int tag, int aclass);
  21 static int asn1_set_seq_out(STACK_OF(const_ASN1_VALUE) *sk,
  22                             unsigned char **out,
  23                             int skcontlen, const ASN1_ITEM *item,
  24                             int do_sort, int iclass);
  25 static int asn1_template_ex_i2d(const ASN1_VALUE **pval, unsigned char **out,
  26                                 const ASN1_TEMPLATE *tt, int tag, int aclass);
  27 static int asn1_item_flags_i2d(const ASN1_VALUE *val, unsigned char **out,
  28                                const ASN1_ITEM *it, int flags);
  29 static int asn1_ex_i2c(const ASN1_VALUE **pval, unsigned char *cout, int *putype,
  30                        const ASN1_ITEM *it);
  31
  32 /*
  33  * Top level i2d equivalents: the 'ndef' variant instructs the encoder to use
  34  * indefinite length constructed encoding, where appropriate
  35  */
  36
  37 int ASN1_item_ndef_i2d(const ASN1_VALUE *val, unsigned char **out,
  38                        const ASN1_ITEM *it)
  39 {
  40     return asn1_item_flags_i2d(val, out, it, ASN1_TFLG_NDEF);
  41 }
  42
  43 int ASN1_item_i2d(const ASN1_VALUE *val, unsigned char **out, const ASN1_ITEM *it)
  44 {
  45     return asn1_item_flags_i2d(val, out, it, 0);
  46 }
  47
  48 /*
  49  * Encode an ASN1 item, this is use by the standard 'i2d' function. 'out'
  50  * points to a buffer to output the data to. The new i2d has one additional
  51  * feature. If the output buffer is NULL (i.e. *out == NULL) then a buffer is
  52  * allocated and populated with the encoding.
  53  */
  54
  55 static int asn1_item_flags_i2d(const ASN1_VALUE *val, unsigned char **out,
  56                                const ASN1_ITEM *it, int flags)
  57 {
  58     if (out && !*out) {
  59         unsigned char *p, *buf;
  60         int len;
  61
  62         len = ASN1_item_ex_i2d(&val, NULL, it, -1, flags);
  63         if (len <= 0)
  64             return len;
  65         if ((buf = OPENSSL_malloc(len)) == NULL) {
  66             ASN1err(ASN1_F_ASN1_ITEM_FLAGS_I2D, ERR_R_MALLOC_FAILURE);
  67             return -1;
  68         }
  69         p = buf;
  70         ASN1_item_ex_i2d(&val, &p, it, -1, flags);
  71         *out = buf;
  72         return len;
  73     }
  74
  75     return ASN1_item_ex_i2d(&val, out, it, -1, flags);
  76 }
  77
  78 /*
  79  * Encode an item, taking care of IMPLICIT tagging (if any). This function
  80  * performs the normal item handling: it can be used in external types.
  81  */
  82
  83 int ASN1_item_ex_i2d(const ASN1_VALUE **pval, unsigned char **out,
  84                      const ASN1_ITEM *it, int tag, int aclass)
  85 {
  86     const ASN1_TEMPLATE *tt = NULL;
  87     int i, seqcontlen, seqlen, ndef = 1;
  88     const ASN1_EXTERN_FUNCS *ef;
  89     const ASN1_AUX *aux = it->funcs;
  90     ASN1_aux_const_cb *asn1_cb = NULL;
  91
  92     if ((it->itype != ASN1_ITYPE_PRIMITIVE) && !*pval)
  93         return 0;
  94
  95     if (aux != NULL) {
  96         asn1_cb = ((aux->flags & ASN1_AFLG_CONST_CB) != 0) ? aux->asn1_const_cb
  97             : (ASN1_aux_const_cb *)aux->asn1_cb; /* backward compatibility */
  98     }
  99
 100     switch (it->itype) {
 101
 102     case ASN1_ITYPE_PRIMITIVE:
 103         if (it->templates)
 104             return asn1_template_ex_i2d(pval, out, it->templates,
 105                                         tag, aclass);
 106         return asn1_i2d_ex_primitive(pval, out, it, tag, aclass);
 107
 108     case ASN1_ITYPE_MSTRING:
 109         return asn1_i2d_ex_primitive(pval, out, it, -1, aclass);
 110
 111     case ASN1_ITYPE_CHOICE:
 112         if (asn1_cb && !asn1_cb(ASN1_OP_I2D_PRE, pval, it, NULL))
 113             return 0;
 114         i = asn1_get_choice_selector_const(pval, it);
 115         if ((i >= 0) && (i < it->tcount)) {
 116             const ASN1_VALUE **pchval;
 117             const ASN1_TEMPLATE *chtt;
 118             chtt = it->templates + i;
 119             pchval = asn1_get_const_field_ptr(pval, chtt);
 120             return asn1_template_ex_i2d(pchval, out, chtt, -1, aclass);
 121         }
 122         /* Fixme: error condition if selector out of range */
 123         if (asn1_cb && !asn1_cb(ASN1_OP_I2D_POST, pval, it, NULL))
 124             return 0;
 125         break;
 126
 127     case ASN1_ITYPE_EXTERN:
 128         /* If new style i2d it does all the work */
 129         ef = it->funcs;
 130         return ef->asn1_ex_i2d(pval, out, it, tag, aclass);
 131
 132     case ASN1_ITYPE_NDEF_SEQUENCE:
 133         /* Use indefinite length constructed if requested */
 134         if (aclass & ASN1_TFLG_NDEF)
 135             ndef = 2;
 136         /* fall through */
 137
 138     case ASN1_ITYPE_SEQUENCE:
 139         i = asn1_enc_restore(&seqcontlen, out, pval, it);
 140         /* An error occurred */
 141         if (i < 0)
 142             return 0;
 143         /* We have a valid cached encoding... */
 144         if (i > 0)
 145             return seqcontlen;
 146         /* Otherwise carry on */
 147         seqcontlen = 0;
 148         /* If no IMPLICIT tagging set to SEQUENCE, UNIVERSAL */
 149         if (tag == -1) {
 150             tag = V_ASN1_SEQUENCE;
 151             /* Retain any other flags in aclass */
 152             aclass = (aclass & ~ASN1_TFLG_TAG_CLASS)
 153                 | V_ASN1_UNIVERSAL;
 154         }
 155         if (asn1_cb && !asn1_cb(ASN1_OP_I2D_PRE, pval, it, NULL))
 156             return 0;
 157         /* First work out sequence content length */
 158         for (i = 0, tt = it->templates; i < it->tcount; tt++, i++) {
 159             const ASN1_TEMPLATE *seqtt;
 160             const ASN1_VALUE **pseqval;
 161             int tmplen;
 162             seqtt = asn1_do_adb(*pval, tt, 1);
 163             if (!seqtt)
 164                 return 0;
 165             pseqval = asn1_get_const_field_ptr(pval, seqtt);
 166             tmplen = asn1_template_ex_i2d(pseqval, NULL, seqtt, -1, aclass);
 167             if (tmplen == -1 || (tmplen > INT_MAX - seqcontlen))
 168                 return -1;
 169             seqcontlen += tmplen;
 170         }
 171
 172         seqlen = ASN1_object_size(ndef, seqcontlen, tag);
 173         if (!out || seqlen == -1)
 174             return seqlen;
 175         /* Output SEQUENCE header */
 176         ASN1_put_object(out, ndef, seqcontlen, tag, aclass);
 177         for (i = 0, tt = it->templates; i < it->tcount; tt++, i++) {
 178             const ASN1_TEMPLATE *seqtt;
 179             const ASN1_VALUE **pseqval;
 180             seqtt = asn1_do_adb(*pval, tt, 1);
 181             if (!seqtt)
 182                 return 0;
 183             pseqval = asn1_get_const_field_ptr(pval, seqtt);
 184             /* FIXME: check for errors in enhanced version */
 185             asn1_template_ex_i2d(pseqval, out, seqtt, -1, aclass);
 186         }
 187         if (ndef == 2)
 188             ASN1_put_eoc(out);
 189         if (asn1_cb && !asn1_cb(ASN1_OP_I2D_POST, pval, it, NULL))
 190             return 0;
 191         return seqlen;
 192
 193     default:
 194         return 0;
 195
 196     }
 197     return 0;
 198 }
 199
 200 static int asn1_template_ex_i2d(const ASN1_VALUE **pval, unsigned char **out,
 201                                 const ASN1_TEMPLATE *tt, int tag, int iclass)
 202 {
 203     int i, ret, flags, ttag, tclass, ndef;
 204     const ASN1_VALUE *tval;
 205     flags = tt->flags;
 206
 207     /*
 208      * If field is embedded then val needs fixing so it is a pointer to
 209      * a pointer to a field.
 210      */
 211     if (flags & ASN1_TFLG_EMBED) {
 212         tval = (ASN1_VALUE *)pval;
 213         pval = &tval;
 214     }
 215     /*
 216      * Work out tag and class to use: tagging may come either from the
 217      * template or the arguments, not both because this would create
 218      * ambiguity. Additionally the iclass argument may contain some
 219      * additional flags which should be noted and passed down to other
 220      * levels.
 221      */
 222     if (flags & ASN1_TFLG_TAG_MASK) {
 223         /* Error if argument and template tagging */
 224         if (tag != -1)
 225             /* FIXME: error code here */
 226             return -1;
 227         /* Get tagging from template */
 228         ttag = tt->tag;
 229         tclass = flags & ASN1_TFLG_TAG_CLASS;
 230     } else if (tag != -1) {
 231         /* No template tagging, get from arguments */
 232         ttag = tag;
 233         tclass = iclass & ASN1_TFLG_TAG_CLASS;
 234     } else {
 235         ttag = -1;
 236         tclass = 0;
 237     }
 238     /*
 239      * Remove any class mask from iflag.
 240      */
 241     iclass &= ~ASN1_TFLG_TAG_CLASS;
 242
 243     /*
 244      * At this point 'ttag' contains the outer tag to use, 'tclass' is the
 245      * class and iclass is any flags passed to this function.
 246      */
 247
 248     /* if template and arguments require ndef, use it */
 249     if ((flags & ASN1_TFLG_NDEF) && (iclass & ASN1_TFLG_NDEF))
 250         ndef = 2;
 251     else
 252         ndef = 1;
 253
 254     if (flags & ASN1_TFLG_SK_MASK) {
 255         /* SET OF, SEQUENCE OF */
 256         STACK_OF(const_ASN1_VALUE) *sk = (STACK_OF(const_ASN1_VALUE) *)*pval;
 257         int isset, sktag, skaclass;
 258         int skcontlen, sklen;
 259         const ASN1_VALUE *skitem;
 260
 261         if (!*pval)
 262             return 0;
 263
 264         if (flags & ASN1_TFLG_SET_OF) {
 265             isset = 1;
 266             /* 2 means we reorder */
 267             if (flags & ASN1_TFLG_SEQUENCE_OF)
 268                 isset = 2;
 269         } else
 270             isset = 0;
 271
 272         /*
 273          * Work out inner tag value: if EXPLICIT or no tagging use underlying
 274          * type.
 275          */
 276         if ((ttag != -1) && !(flags & ASN1_TFLG_EXPTAG)) {
 277             sktag = ttag;
 278             skaclass = tclass;
 279         } else {
 280             skaclass = V_ASN1_UNIVERSAL;
 281             if (isset)
 282                 sktag = V_ASN1_SET;
 283             else
 284                 sktag = V_ASN1_SEQUENCE;
 285         }
 286
 287         /* Determine total length of items */
 288         skcontlen = 0;
 289         for (i = 0; i < sk_const_ASN1_VALUE_num(sk); i++) {
 290             int tmplen;
 291             skitem = sk_const_ASN1_VALUE_value(sk, i);
 292             tmplen = ASN1_item_ex_i2d(&skitem, NULL, ASN1_ITEM_ptr(tt->item),
 293                                       -1, iclass);
 294             if (tmplen == -1 || (skcontlen > INT_MAX - tmplen))
 295                 return -1;
 296             skcontlen += tmplen;
 297         }
 298         sklen = ASN1_object_size(ndef, skcontlen, sktag);
 299         if (sklen == -1)
 300             return -1;
 301         /* If EXPLICIT need length of surrounding tag */
 302         if (flags & ASN1_TFLG_EXPTAG)
 303             ret = ASN1_object_size(ndef, sklen, ttag);
 304         else
 305             ret = sklen;
 306
 307         if (!out || ret == -1)
 308             return ret;
 309
 310         /* Now encode this lot... */
 311         /* EXPLICIT tag */
 312         if (flags & ASN1_TFLG_EXPTAG)
 313             ASN1_put_object(out, ndef, sklen, ttag, tclass);
 314         /* SET or SEQUENCE and IMPLICIT tag */
 315         ASN1_put_object(out, ndef, skcontlen, sktag, skaclass);
 316         /* And the stuff itself */
 317         asn1_set_seq_out(sk, out, skcontlen, ASN1_ITEM_ptr(tt->item),
 318                          isset, iclass);
 319         if (ndef == 2) {
 320             ASN1_put_eoc(out);
 321             if (flags & ASN1_TFLG_EXPTAG)
 322                 ASN1_put_eoc(out);
 323         }
 324
 325         return ret;
 326     }
 327
 328     if (flags & ASN1_TFLG_EXPTAG) {
 329         /* EXPLICIT tagging */
 330         /* Find length of tagged item */
 331         i = ASN1_item_ex_i2d(pval, NULL, ASN1_ITEM_ptr(tt->item), -1, iclass);
 332         if (!i)
 333             return 0;
 334         /* Find length of EXPLICIT tag */
 335         ret = ASN1_object_size(ndef, i, ttag);
 336         if (out && ret != -1) {
 337             /* Output tag and item */
 338             ASN1_put_object(out, ndef, i, ttag, tclass);
 339             ASN1_item_ex_i2d(pval, out, ASN1_ITEM_ptr(tt->item), -1, iclass);
 340             if (ndef == 2)
 341                 ASN1_put_eoc(out);
 342         }
 343         return ret;
 344     }
 345
 346     /* Either normal or IMPLICIT tagging: combine class and flags */
 347     return ASN1_item_ex_i2d(pval, out, ASN1_ITEM_ptr(tt->item),
 348                             ttag, tclass | iclass);
 349
 350 }
 351
 352 /* Temporary structure used to hold DER encoding of items for SET OF */
 353
 354 typedef struct {
 355     unsigned char *data;
 356     int length;
 357     const ASN1_VALUE *field;
 358 } DER_ENC;
 359
 360 static int der_cmp(const void *a, const void *b)
 361 {
 362     const DER_ENC *d1 = a, *d2 = b;
 363     int cmplen, i;
 364     cmplen = (d1->length < d2->length) ? d1->length : d2->length;
 365     i = memcmp(d1->data, d2->data, cmplen);
 366     if (i)
 367         return i;
 368     return d1->length - d2->length;
 369 }
 370
 371 /* Output the content octets of SET OF or SEQUENCE OF */
 372
 373 static int asn1_set_seq_out(STACK_OF(const_ASN1_VALUE) *sk,
 374                             unsigned char **out,
 375                             int skcontlen, const ASN1_ITEM *item,
 376                             int do_sort, int iclass)
 377 {
 378     int i;
 379     const ASN1_VALUE *skitem;
 380     unsigned char *tmpdat = NULL, *p = NULL;
 381     DER_ENC *derlst = NULL, *tder;
 382     if (do_sort) {
 383         /* Don't need to sort less than 2 items */
 384         if (sk_const_ASN1_VALUE_num(sk) < 2)
 385             do_sort = 0;
 386         else {
 387             derlst = OPENSSL_malloc(sk_const_ASN1_VALUE_num(sk)
 388                                     * sizeof(*derlst));
 389             if (derlst == NULL)
 390                 return 0;
 391             tmpdat = OPENSSL_malloc(skcontlen);
 392             if (tmpdat == NULL) {
 393                 OPENSSL_free(derlst);
 394                 return 0;
 395             }
 396         }
 397     }
 398     /* If not sorting just output each item */
 399     if (!do_sort) {
 400         for (i = 0; i < sk_const_ASN1_VALUE_num(sk); i++) {
 401             skitem = sk_const_ASN1_VALUE_value(sk, i);
 402             ASN1_item_ex_i2d(&skitem, out, item, -1, iclass);
 403         }
 404         return 1;
 405     }
 406     p = tmpdat;
 407
 408     /* Doing sort: build up a list of each member's DER encoding */
 409     for (i = 0, tder = derlst; i < sk_const_ASN1_VALUE_num(sk); i++, tder++) {
 410         skitem = sk_const_ASN1_VALUE_value(sk, i);
 411         tder->data = p;
 412         tder->length = ASN1_item_ex_i2d(&skitem, &p, item, -1, iclass);
 413         tder->field = skitem;
 414     }
 415
 416     /* Now sort them */
 417     qsort(derlst, sk_const_ASN1_VALUE_num(sk), sizeof(*derlst), der_cmp);
 418     /* Output sorted DER encoding */
 419     p = *out;
 420     for (i = 0, tder = derlst; i < sk_const_ASN1_VALUE_num(sk); i++, tder++) {
 421         memcpy(p, tder->data, tder->length);
 422         p += tder->length;
 423     }
 424     *out = p;
 425     /* If do_sort is 2 then reorder the STACK */
 426     if (do_sort == 2) {
 427         for (i = 0, tder = derlst; i < sk_const_ASN1_VALUE_num(sk); i++, tder++)
 428             (void)sk_const_ASN1_VALUE_set(sk, i, tder->field);
 429     }
 430     OPENSSL_free(derlst);
 431     OPENSSL_free(tmpdat);
 432     return 1;
 433 }
 434
 435 static int asn1_i2d_ex_primitive(const ASN1_VALUE **pval, unsigned char **out,
 436                                  const ASN1_ITEM *it, int tag, int aclass)
 437 {
 438     int len;
 439     int utype;
 440     int usetag;
 441     int ndef = 0;
 442
 443     utype = it->utype;
 444
 445     /*
 446      * Get length of content octets and maybe find out the underlying type.
 447      */
 448
 449     len = asn1_ex_i2c(pval, NULL, &utype, it);
 450
 451     /*
 452      * If SEQUENCE, SET or OTHER then header is included in pseudo content
 453      * octets so don't include tag+length. We need to check here because the
 454      * call to asn1_ex_i2c() could change utype.
 455      */
 456     if ((utype == V_ASN1_SEQUENCE) || (utype == V_ASN1_SET) ||
 457         (utype == V_ASN1_OTHER))
 458         usetag = 0;
 459     else
 460         usetag = 1;
 461
 462     /* -1 means omit type */
 463
 464     if (len == -1)
 465         return 0;
 466
 467     /* -2 return is special meaning use ndef */
 468     if (len == -2) {
 469         ndef = 2;
 470         len = 0;
 471     }
 472
 473     /* If not implicitly tagged get tag from underlying type */
 474     if (tag == -1)
 475         tag = utype;
 476
 477     /* Output tag+length followed by content octets */
 478     if (out) {
 479         if (usetag)
 480             ASN1_put_object(out, ndef, len, tag, aclass);
 481         asn1_ex_i2c(pval, *out, &utype, it);
 482         if (ndef)
 483             ASN1_put_eoc(out);
 484         else
 485             *out += len;
 486     }
 487
 488     if (usetag)
 489         return ASN1_object_size(ndef, len, tag);
 490     return len;
 491 }
 492
 493 /* Produce content octets from a structure */
 494
 495 static int asn1_ex_i2c(const ASN1_VALUE **pval, unsigned char *cout, int *putype,
 496                        const ASN1_ITEM *it)
 497 {
 498     ASN1_BOOLEAN *tbool = NULL;
 499     ASN1_STRING *strtmp;
 500     ASN1_OBJECT *otmp;
 501     int utype;
 502     const unsigned char *cont;
 503     unsigned char c;
 504     int len;
 505     const ASN1_PRIMITIVE_FUNCS *pf;
 506     pf = it->funcs;
 507     if (pf && pf->prim_i2c)
 508         return pf->prim_i2c(pval, cout, putype, it);
 509
 510     /* Should type be omitted? */
 511     if ((it->itype != ASN1_ITYPE_PRIMITIVE)
 512         || (it->utype != V_ASN1_BOOLEAN)) {
 513         if (!*pval)
 514             return -1;
 515     }
 516
 517     if (it->itype == ASN1_ITYPE_MSTRING) {
 518         /* If MSTRING type set the underlying type */
 519         strtmp = (ASN1_STRING *)*pval;
 520         utype = strtmp->type;
 521         *putype = utype;
 522     } else if (it->utype == V_ASN1_ANY) {
 523         /* If ANY set type and pointer to value */
 524         ASN1_TYPE *typ;
 525         typ = (ASN1_TYPE *)*pval;
 526         utype = typ->type;
 527         *putype = utype;
 528         pval = (const ASN1_VALUE **)&typ->value.asn1_value; /* actually is const */
 529     } else
 530         utype = *putype;
 531
 532     switch (utype) {
 533     case V_ASN1_OBJECT:
 534         otmp = (ASN1_OBJECT *)*pval;
 535         cont = otmp->data;
 536         len = otmp->length;
 537         if (cont == NULL || len == 0)
 538             return -1;
 539         break;
 540
 541     case V_ASN1_NULL:
 542         cont = NULL;
 543         len = 0;
 544         break;
 545
 546     case V_ASN1_BOOLEAN:
 547         tbool = (ASN1_BOOLEAN *)pval;
 548         if (*tbool == -1)
 549             return -1;
 550         if (it->utype != V_ASN1_ANY) {
 551             /*
 552              * Default handling if value == size field then omit
 553              */
 554             if (*tbool && (it->size > 0))
 555                 return -1;
 556             if (!*tbool && !it->size)
 557                 return -1;
 558         }
 559         c = (unsigned char)*tbool;
 560         cont = &c;
 561         len = 1;
 562         break;
 563
 564     case V_ASN1_BIT_STRING:
 565         return i2c_ASN1_BIT_STRING((ASN1_BIT_STRING *)*pval,
 566                                    cout ? &cout : NULL);
 567
 568     case V_ASN1_INTEGER:
 569     case V_ASN1_ENUMERATED:
 570         /*
 571          * These are all have the same content format as ASN1_INTEGER
 572          */
 573         return i2c_ASN1_INTEGER((ASN1_INTEGER *)*pval, cout ? &cout : NULL);
 574
 575     case V_ASN1_OCTET_STRING:
 576     case V_ASN1_NUMERICSTRING:
 577     case V_ASN1_PRINTABLESTRING:
 578     case V_ASN1_T61STRING:
 579     case V_ASN1_VIDEOTEXSTRING:
 580     case V_ASN1_IA5STRING:
 581     case V_ASN1_UTCTIME:
 582     case V_ASN1_GENERALIZEDTIME:
 583     case V_ASN1_GRAPHICSTRING:
 584     case V_ASN1_VISIBLESTRING:
 585     case V_ASN1_GENERALSTRING:
 586     case V_ASN1_UNIVERSALSTRING:
 587     case V_ASN1_BMPSTRING:
 588     case V_ASN1_UTF8STRING:
 589     case V_ASN1_SEQUENCE:
 590     case V_ASN1_SET:
 591     default:
 592         /* All based on ASN1_STRING and handled the same */
 593         strtmp = (ASN1_STRING *)*pval;
 594         /* Special handling for NDEF */
 595         if ((it->size == ASN1_TFLG_NDEF)
 596             && (strtmp->flags & ASN1_STRING_FLAG_NDEF)) {
 597             if (cout) {
 598                 strtmp->data = cout;
 599                 strtmp->length = 0;
 600             }
 601             /* Special return code */
 602             return -2;
 603         }
 604         cont = strtmp->data;
 605         len = strtmp->length;
 606
 607         break;
 608
 609     }
 610     if (cout && len)
 611         memcpy(cout, cont, len);
 612     return len;
 613 }