text: /* tasn_enc.c */
  /*
   * Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL project
   * 2000.
   */
  /* ====================================================================
   * Copyright (c) 2000-2004 The OpenSSL Project.  All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   *
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in
   *    the documentation and/or other materials provided with the
   *    distribution.
   *
   * 3. All advertising materials mentioning features or use of this
   *    software must display the following acknowledgment:
   *    "This product includes software developed by the OpenSSL Project
   *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
   *
   * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
   *    endorse or promote products derived from this software without
   *    prior written permission. For written permission, please contact
   *    licensing@OpenSSL.org.
   *
   * 5. Products derived from this software may not be called "OpenSSL"
   *    nor may "OpenSSL" appear in their names without prior written
   *    permission of the OpenSSL Project.
   *
   * 6. Redistributions of any form whatsoever must retain the following
   *    acknowledgment:
   *    "This product includes software developed by the OpenSSL Project
   *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
   *
   * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
   * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
   * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
   * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
   * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
   * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
   * OF THE POSSIBILITY OF SUCH DAMAGE.
   * ====================================================================
   *
   * This product includes cryptographic software written by Eric Young
   * (eay@cryptsoft.com).  This product includes software written by Tim
   * Hudson (tjh@cryptsoft.com).
   *
   */
  
  #include <stddef.h>
  #include <string.h>
  #include "internal/cryptlib.h"
  #include <openssl/asn1.h>
  #include <openssl/asn1t.h>
  #include <openssl/objects.h>
  #include "internal/asn1_int.h"
  #include "asn1_locl.h"
  
  static int asn1_i2d_ex_primitive(ASN1_VALUE **pval, unsigned char **out,
                                   const ASN1_ITEM *it, int tag, int aclass);
  static int asn1_set_seq_out(STACK_OF(ASN1_VALUE) *sk, unsigned char **out,
                              int skcontlen, const ASN1_ITEM *item,
                              int do_sort, int iclass);
  static int asn1_template_ex_i2d(ASN1_VALUE **pval, unsigned char **out,
                                  const ASN1_TEMPLATE *tt, int tag, int aclass);
  static int asn1_item_flags_i2d(ASN1_VALUE *val, unsigned char **out,
                                 const ASN1_ITEM *it, int flags);
  static int asn1_ex_i2c(ASN1_VALUE **pval, unsigned char *cout, int *putype,
                         const ASN1_ITEM *it);
  
  /*
   * Top level i2d equivalents: the 'ndef' variant instructs the encoder to use
   * indefinite length constructed encoding, where appropriate
   */
  
  int ASN1_item_ndef_i2d(ASN1_VALUE *val, unsigned char **out,
                         const ASN1_ITEM *it)
  {
      return asn1_item_flags_i2d(val, out, it, ASN1_TFLG_NDEF);
  }
  
  int ASN1_item_i2d(ASN1_VALUE *val, unsigned char **out, const ASN1_ITEM *it)
  {
      return asn1_item_flags_i2d(val, out, it, 0);
  }
  
  /*
   * Encode an ASN1 item, this is use by the standard 'i2d' function. 'out'
   * points to a buffer to output the data to. The new i2d has one additional
   * feature. If the output buffer is NULL (i.e. *out == NULL) then a buffer is
   * allocated and populated with the encoding.
   */
  
  static int asn1_item_flags_i2d(ASN1_VALUE *val, unsigned char **out,
                                 const ASN1_ITEM *it, int flags)
  {
      if (out && !*out) {
          unsigned char *p, *buf;
          int len;
          len = ASN1_item_ex_i2d(&val, NULL, it, -1, flags);
          if (len <= 0)
              return len;
          buf = OPENSSL_malloc(len);
          if (!buf)
              return -1;
          p = buf;
          ASN1_item_ex_i2d(&val, &p, it, -1, flags);
          *out = buf;
          return len;
      }
  
      return ASN1_item_ex_i2d(&val, out, it, -1, flags);
  }
  
  /*
   * Encode an item, taking care of IMPLICIT tagging (if any). This function
   * performs the normal item handling: it can be used in external types.
   */
  
  int ASN1_item_ex_i2d(ASN1_VALUE **pval, unsigned char **out,
                       const ASN1_ITEM *it, int tag, int aclass)
  {
      const ASN1_TEMPLATE *tt = NULL;
      int i, seqcontlen, seqlen, ndef = 1;
      const ASN1_EXTERN_FUNCS *ef;
      const ASN1_AUX *aux = it->funcs;
      ASN1_aux_cb *asn1_cb = 0;
  
      if ((it->itype != ASN1_ITYPE_PRIMITIVE) && !*pval)
          return 0;
  
      if (aux && aux->asn1_cb)
          asn1_cb = aux->asn1_cb;
  
      switch (it->itype) {
  
      case ASN1_ITYPE_PRIMITIVE:
          if (it->templates)
              return asn1_template_ex_i2d(pval, out, it->templates,
                                          tag, aclass);
          return asn1_i2d_ex_primitive(pval, out, it, tag, aclass);
  
      case ASN1_ITYPE_MSTRING:
          return asn1_i2d_ex_primitive(pval, out, it, -1, aclass);
  
      case ASN1_ITYPE_CHOICE:
          if (asn1_cb && !asn1_cb(ASN1_OP_I2D_PRE, pval, it, NULL))
              return 0;
          i = asn1_get_choice_selector(pval, it);
          if ((i >= 0) && (i < it->tcount)) {
              ASN1_VALUE **pchval;
              const ASN1_TEMPLATE *chtt;
              chtt = it->templates + i;
              pchval = asn1_get_field_ptr(pval, chtt);
              return asn1_template_ex_i2d(pchval, out, chtt, -1, aclass);
          }
          /* Fixme: error condition if selector out of range */
          if (asn1_cb && !asn1_cb(ASN1_OP_I2D_POST, pval, it, NULL))
              return 0;
          break;
  
      case ASN1_ITYPE_EXTERN:
          /* If new style i2d it does all the work */
          ef = it->funcs;
          return ef->asn1_ex_i2d(pval, out, it, tag, aclass);
  
      case ASN1_ITYPE_NDEF_SEQUENCE:
          /* Use indefinite length constructed if requested */
          if (aclass & ASN1_TFLG_NDEF)
              ndef = 2;
          /* fall through */
  
      case ASN1_ITYPE_SEQUENCE:
          i = asn1_enc_restore(&seqcontlen, out, pval, it);
          /* An error occurred */
          if (i < 0)
              return 0;
          /* We have a valid cached encoding... */
          if (i > 0)
              return seqcontlen;
          /* Otherwise carry on */
          seqcontlen = 0;
          /* If no IMPLICIT tagging set to SEQUENCE, UNIVERSAL */
          if (tag == -1) {
              tag = V_ASN1_SEQUENCE;
              /* Retain any other flags in aclass */
              aclass = (aclass & ~ASN1_TFLG_TAG_CLASS)
                  | V_ASN1_UNIVERSAL;
          }
          if (asn1_cb && !asn1_cb(ASN1_OP_I2D_PRE, pval, it, NULL))
              return 0;
          /* First work out sequence content length */
          for (i = 0, tt = it->templates; i < it->tcount; tt++, i++) {
              const ASN1_TEMPLATE *seqtt;
              ASN1_VALUE **pseqval;
              seqtt = asn1_do_adb(pval, tt, 1);
              if (!seqtt)
                  return 0;
              pseqval = asn1_get_field_ptr(pval, seqtt);
              /* FIXME: check for errors in enhanced version */
              seqcontlen += asn1_template_ex_i2d(pseqval, NULL, seqtt,
                                                 -1, aclass);
          }
  
          seqlen = ASN1_object_size(ndef, seqcontlen, tag);
          if (!out)
              return seqlen;
          /* Output SEQUENCE header */
          ASN1_put_object(out, ndef, seqcontlen, tag, aclass);
          for (i = 0, tt = it->templates; i < it->tcount; tt++, i++) {
              const ASN1_TEMPLATE *seqtt;
              ASN1_VALUE **pseqval;
              seqtt = asn1_do_adb(pval, tt, 1);
              if (!seqtt)
                  return 0;
              pseqval = asn1_get_field_ptr(pval, seqtt);
              /* FIXME: check for errors in enhanced version */
              asn1_template_ex_i2d(pseqval, out, seqtt, -1, aclass);
          }
          if (ndef == 2)
              ASN1_put_eoc(out);
          if (asn1_cb && !asn1_cb(ASN1_OP_I2D_POST, pval, it, NULL))
              return 0;
          return seqlen;
  
      default:
          return 0;
  
      }
      return 0;
  }
  
  static int asn1_template_ex_i2d(ASN1_VALUE **pval, unsigned char **out,
                                  const ASN1_TEMPLATE *tt, int tag, int iclass)
  {
      int i, ret, flags, ttag, tclass, ndef;
      flags = tt->flags;
      /*
       * Work out tag and class to use: tagging may come either from the
       * template or the arguments, not both because this would create
       * ambiguity. Additionally the iclass argument may contain some
       * additional flags which should be noted and passed down to other
       * levels.
       */
      if (flags & ASN1_TFLG_TAG_MASK) {
          /* Error if argument and template tagging */
          if (tag != -1)
              /* FIXME: error code here */
              return -1;
          /* Get tagging from template */
          ttag = tt->tag;
          tclass = flags & ASN1_TFLG_TAG_CLASS;
      } else if (tag != -1) {
          /* No template tagging, get from arguments */
          ttag = tag;
          tclass = iclass & ASN1_TFLG_TAG_CLASS;
      } else {
          ttag = -1;
          tclass = 0;
      }
      /*
       * Remove any class mask from iflag.
       */
      iclass &= ~ASN1_TFLG_TAG_CLASS;
  
      /*
       * At this point 'ttag' contains the outer tag to use, 'tclass' is the
       * class and iclass is any flags passed to this function.
       */
  
      /* if template and arguments require ndef, use it */
      if ((flags & ASN1_TFLG_NDEF) && (iclass & ASN1_TFLG_NDEF))
          ndef = 2;
      else
          ndef = 1;
  
      if (flags & ASN1_TFLG_SK_MASK) {
          /* SET OF, SEQUENCE OF */
          STACK_OF(ASN1_VALUE) *sk = (STACK_OF(ASN1_VALUE) *)*pval;
          int isset, sktag, skaclass;
          int skcontlen, sklen;
          ASN1_VALUE *skitem;
  
          if (!*pval)
              return 0;
  
          if (flags & ASN1_TFLG_SET_OF) {
              isset = 1;
              /* 2 means we reorder */
              if (flags & ASN1_TFLG_SEQUENCE_OF)
                  isset = 2;
          } else
              isset = 0;
  
          /*
           * Work out inner tag value: if EXPLICIT or no tagging use underlying
           * type.
           */
          if ((ttag != -1) && !(flags & ASN1_TFLG_EXPTAG)) {
              sktag = ttag;
              skaclass = tclass;
          } else {
              skaclass = V_ASN1_UNIVERSAL;
              if (isset)
                  sktag = V_ASN1_SET;
              else
                  sktag = V_ASN1_SEQUENCE;
          }
  
          /* Determine total length of items */
          skcontlen = 0;
          for (i = 0; i < sk_ASN1_VALUE_num(sk); i++) {
              skitem = sk_ASN1_VALUE_value(sk, i);
              skcontlen += ASN1_item_ex_i2d(&skitem, NULL,
                                            ASN1_ITEM_ptr(tt->item),
                                            -1, iclass);
          }
          sklen = ASN1_object_size(ndef, skcontlen, sktag);
          /* If EXPLICIT need length of surrounding tag */
          if (flags & ASN1_TFLG_EXPTAG)
              ret = ASN1_object_size(ndef, sklen, ttag);
          else
              ret = sklen;
  
          if (!out)
              return ret;
  
          /* Now encode this lot... */
          /* EXPLICIT tag */
          if (flags & ASN1_TFLG_EXPTAG)
              ASN1_put_object(out, ndef, sklen, ttag, tclass);
          /* SET or SEQUENCE and IMPLICIT tag */
          ASN1_put_object(out, ndef, skcontlen, sktag, skaclass);
          /* And the stuff itself */
          asn1_set_seq_out(sk, out, skcontlen, ASN1_ITEM_ptr(tt->item),
                           isset, iclass);
          if (ndef == 2) {
              ASN1_put_eoc(out);
              if (flags & ASN1_TFLG_EXPTAG)
                  ASN1_put_eoc(out);
          }
  
          return ret;
      }
  
      if (flags & ASN1_TFLG_EXPTAG) {
          /* EXPLICIT tagging */
          /* Find length of tagged item */
          i = ASN1_item_ex_i2d(pval, NULL, ASN1_ITEM_ptr(tt->item), -1, iclass);
          if (!i)
              return 0;
          /* Find length of EXPLICIT tag */
          ret = ASN1_object_size(ndef, i, ttag);
          if (out) {
              /* Output tag and item */
              ASN1_put_object(out, ndef, i, ttag, tclass);
              ASN1_item_ex_i2d(pval, out, ASN1_ITEM_ptr(tt->item), -1, iclass);
              if (ndef == 2)
                  ASN1_put_eoc(out);
          }
          return ret;
      }
  
      /* Either normal or IMPLICIT tagging: combine class and flags */
      return ASN1_item_ex_i2d(pval, out, ASN1_ITEM_ptr(tt->item),
                              ttag, tclass | iclass);
  
  }
  
  /* Temporary structure used to hold DER encoding of items for SET OF */
  
  typedef struct {
      unsigned char *data;
      int length;
      ASN1_VALUE *field;
  } DER_ENC;
  
  static int der_cmp(const void *a, const void *b)
  {
      const DER_ENC *d1 = a, *d2 = b;
      int cmplen, i;
      cmplen = (d1->length < d2->length) ? d1->length : d2->length;
      i = memcmp(d1->data, d2->data, cmplen);
      if (i)
          return i;
      return d1->length - d2->length;
  }
  
  /* Output the content octets of SET OF or SEQUENCE OF */
  
  static int asn1_set_seq_out(STACK_OF(ASN1_VALUE) *sk, unsigned char **out,
                              int skcontlen, const ASN1_ITEM *item,
                              int do_sort, int iclass)
  {
      int i;
      ASN1_VALUE *skitem;
      unsigned char *tmpdat = NULL, *p = NULL;
      DER_ENC *derlst = NULL, *tder;
      if (do_sort) {
          /* Don't need to sort less than 2 items */
          if (sk_ASN1_VALUE_num(sk) < 2)
              do_sort = 0;
          else {
              derlst = OPENSSL_malloc(sk_ASN1_VALUE_num(sk)
                                      * sizeof(*derlst));
              if (!derlst)
                  return 0;
              tmpdat = OPENSSL_malloc(skcontlen);
              if (!tmpdat) {
                  OPENSSL_free(derlst);
                  return 0;
              }
          }
      }
      /* If not sorting just output each item */
      if (!do_sort) {
          for (i = 0; i < sk_ASN1_VALUE_num(sk); i++) {
              skitem = sk_ASN1_VALUE_value(sk, i);
              ASN1_item_ex_i2d(&skitem, out, item, -1, iclass);
          }
          return 1;
      }
      p = tmpdat;
  
      /* Doing sort: build up a list of each member's DER encoding */
      for (i = 0, tder = derlst; i < sk_ASN1_VALUE_num(sk); i++, tder++) {
          skitem = sk_ASN1_VALUE_value(sk, i);
          tder->data = p;
          tder->length = ASN1_item_ex_i2d(&skitem, &p, item, -1, iclass);
          tder->field = skitem;
      }
  
      /* Now sort them */
      qsort(derlst, sk_ASN1_VALUE_num(sk), sizeof(*derlst), der_cmp);
      /* Output sorted DER encoding */
      p = *out;
      for (i = 0, tder = derlst; i < sk_ASN1_VALUE_num(sk); i++, tder++) {
          memcpy(p, tder->data, tder->length);
          p += tder->length;
      }
      *out = p;
      /* If do_sort is 2 then reorder the STACK */
      if (do_sort == 2) {
          for (i = 0, tder = derlst; i < sk_ASN1_VALUE_num(sk); i++, tder++)
              (void)sk_ASN1_VALUE_set(sk, i, tder->field);
      }
      OPENSSL_free(derlst);
      OPENSSL_free(tmpdat);
      return 1;
  }
  
  static int asn1_i2d_ex_primitive(ASN1_VALUE **pval, unsigned char **out,
                                   const ASN1_ITEM *it, int tag, int aclass)
  {
      int len;
      int utype;
      int usetag;
      int ndef = 0;
  
      utype = it->utype;
  
      /*
       * Get length of content octets and maybe find out the underlying type.
       */
  
      len = asn1_ex_i2c(pval, NULL, &utype, it);
  
      /*
       * If SEQUENCE, SET or OTHER then header is included in pseudo content
       * octets so don't include tag+length. We need to check here because the
       * call to asn1_ex_i2c() could change utype.
       */
      if ((utype == V_ASN1_SEQUENCE) || (utype == V_ASN1_SET) ||
          (utype == V_ASN1_OTHER))
          usetag = 0;
      else
          usetag = 1;
  
      /* -1 means omit type */
  
      if (len == -1)
          return 0;
  
      /* -2 return is special meaning use ndef */
      if (len == -2) {
          ndef = 2;
          len = 0;
      }
  
      /* If not implicitly tagged get tag from underlying type */
      if (tag == -1)
          tag = utype;
  
      /* Output tag+length followed by content octets */
      if (out) {
          if (usetag)
              ASN1_put_object(out, ndef, len, tag, aclass);
          asn1_ex_i2c(pval, *out, &utype, it);
          if (ndef)
              ASN1_put_eoc(out);
          else
              *out += len;
      }
  
      if (usetag)
          return ASN1_object_size(ndef, len, tag);
      return len;
  }
  
  /* Produce content octets from a structure */
  
  static int asn1_ex_i2c(ASN1_VALUE **pval, unsigned char *cout, int *putype,
                         const ASN1_ITEM *it)
  {
      ASN1_BOOLEAN *tbool = NULL;
      ASN1_STRING *strtmp;
      ASN1_OBJECT *otmp;
      int utype;
      const unsigned char *cont;
      unsigned char c;
      int len;
      const ASN1_PRIMITIVE_FUNCS *pf;
      pf = it->funcs;
      if (pf && pf->prim_i2c)
          return pf->prim_i2c(pval, cout, putype, it);
  
      /* Should type be omitted? */
      if ((it->itype != ASN1_ITYPE_PRIMITIVE)
          || (it->utype != V_ASN1_BOOLEAN)) {
          if (!*pval)
              return -1;
      }
  
      if (it->itype == ASN1_ITYPE_MSTRING) {
          /* If MSTRING type set the underlying type */
          strtmp = (ASN1_STRING *)*pval;
          utype = strtmp->type;
          *putype = utype;
      } else if (it->utype == V_ASN1_ANY) {
          /* If ANY set type and pointer to value */
          ASN1_TYPE *typ;
          typ = (ASN1_TYPE *)*pval;
          utype = typ->type;
          *putype = utype;
          pval = &typ->value.asn1_value;
      } else
          utype = *putype;
  
      switch (utype) {
      case V_ASN1_OBJECT:
          otmp = (ASN1_OBJECT *)*pval;
          cont = otmp->data;
          len = otmp->length;
          break;
  
      case V_ASN1_NULL:
          cont = NULL;
          len = 0;
          break;
  
      case V_ASN1_BOOLEAN:
          tbool = (ASN1_BOOLEAN *)pval;
          if (*tbool == -1)
              return -1;
          if (it->utype != V_ASN1_ANY) {
              /*
               * Default handling if value == size field then omit
               */
              if (*tbool && (it->size > 0))
                  return -1;
              if (!*tbool && !it->size)
                  return -1;
          }
          c = (unsigned char)*tbool;
          cont = &c;
          len = 1;
          break;
  
      case V_ASN1_BIT_STRING:
          return i2c_ASN1_BIT_STRING((ASN1_BIT_STRING *)*pval,
                                     cout ? &cout : NULL);
  
      case V_ASN1_INTEGER:
      case V_ASN1_NEG_INTEGER:
      case V_ASN1_ENUMERATED:
      case V_ASN1_NEG_ENUMERATED:
          /*
           * These are all have the same content format as ASN1_INTEGER
           */
          return i2c_ASN1_INTEGER((ASN1_INTEGER *)*pval, cout ? &cout : NULL);
  
      case V_ASN1_OCTET_STRING:
      case V_ASN1_NUMERICSTRING:
      case V_ASN1_PRINTABLESTRING:
      case V_ASN1_T61STRING:
      case V_ASN1_VIDEOTEXSTRING:
      case V_ASN1_IA5STRING:
      case V_ASN1_UTCTIME:
      case V_ASN1_GENERALIZEDTIME:
      case V_ASN1_GRAPHICSTRING:
      case V_ASN1_VISIBLESTRING:
      case V_ASN1_GENERALSTRING:
      case V_ASN1_UNIVERSALSTRING:
      case V_ASN1_BMPSTRING:
      case V_ASN1_UTF8STRING:
      case V_ASN1_SEQUENCE:
      case V_ASN1_SET:
      default:
          /* All based on ASN1_STRING and handled the same */
          strtmp = (ASN1_STRING *)*pval;
          /* Special handling for NDEF */
          if ((it->size == ASN1_TFLG_NDEF)
              && (strtmp->flags & ASN1_STRING_FLAG_NDEF)) {
              if (cout) {
                  strtmp->data = cout;
                  strtmp->length = 0;
              }
              /* Special return code */
              return -2;
          }
          cont = strtmp->data;
          len = strtmp->length;
  
          break;
  
      }
      if (cout && len)
          memcpy(cout, cont, len);
      return len;
  }
  