text: /*
   * Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
   * project.
   */
  /* ====================================================================
   * Copyright (c) 1999-2003 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).
   *
   */
  /* X509 v3 extension utilities */
  
  #include <stdio.h>
  #include <ctype.h>
  #include "internal/cryptlib.h"
  #include <openssl/conf.h>
  #include <openssl/x509v3.h>
  #include "internal/x509_int.h"
  #include <openssl/bn.h>
  
  static char *strip_spaces(char *name);
  static int sk_strcmp(const char *const *a, const char *const *b);
  static STACK_OF(OPENSSL_STRING) *get_email(X509_NAME *name,
                                             GENERAL_NAMES *gens);
  static void str_free(OPENSSL_STRING str);
  static int append_ia5(STACK_OF(OPENSSL_STRING) **sk, ASN1_IA5STRING *email);
  
  static int ipv4_from_asc(unsigned char *v4, const char *in);
  static int ipv6_from_asc(unsigned char *v6, const char *in);
  static int ipv6_cb(const char *elem, int len, void *usr);
  static int ipv6_hex(unsigned char *out, const char *in, int inlen);
  
  /* Add a CONF_VALUE name value pair to stack */
  
  int X509V3_add_value(const char *name, const char *value,
                       STACK_OF(CONF_VALUE) **extlist)
  {
      CONF_VALUE *vtmp = NULL;
      char *tname = NULL, *tvalue = NULL;
  
      if (name && (tname = OPENSSL_strdup(name)) == NULL)
          goto err;
      if (value && (tvalue = OPENSSL_strdup(value)) == NULL)
          goto err;
      if ((vtmp = OPENSSL_malloc(sizeof(*vtmp))) == NULL)
          goto err;
      if (*extlist == NULL && (*extlist = sk_CONF_VALUE_new_null()) == NULL)
          goto err;
      vtmp->section = NULL;
      vtmp->name = tname;
      vtmp->value = tvalue;
      if (!sk_CONF_VALUE_push(*extlist, vtmp))
          goto err;
      return 1;
   err:
      X509V3err(X509V3_F_X509V3_ADD_VALUE, ERR_R_MALLOC_FAILURE);
      OPENSSL_free(vtmp);
      OPENSSL_free(tname);
      OPENSSL_free(tvalue);
      return 0;
  }
  
  int X509V3_add_value_uchar(const char *name, const unsigned char *value,
                             STACK_OF(CONF_VALUE) **extlist)
  {
      return X509V3_add_value(name, (const char *)value, extlist);
  }
  
  /* Free function for STACK_OF(CONF_VALUE) */
  
  void X509V3_conf_free(CONF_VALUE *conf)
  {
      if (!conf)
          return;
      OPENSSL_free(conf->name);
      OPENSSL_free(conf->value);
      OPENSSL_free(conf->section);
      OPENSSL_free(conf);
  }
  
  int X509V3_add_value_bool(const char *name, int asn1_bool,
                            STACK_OF(CONF_VALUE) **extlist)
  {
      if (asn1_bool)
          return X509V3_add_value(name, "TRUE", extlist);
      return X509V3_add_value(name, "FALSE", extlist);
  }
  
  int X509V3_add_value_bool_nf(char *name, int asn1_bool,
                               STACK_OF(CONF_VALUE) **extlist)
  {
      if (asn1_bool)
          return X509V3_add_value(name, "TRUE", extlist);
      return 1;
  }
  
  char *i2s_ASN1_ENUMERATED(X509V3_EXT_METHOD *method, ASN1_ENUMERATED *a)
  {
      BIGNUM *bntmp = NULL;
      char *strtmp = NULL;
  
      if (!a)
          return NULL;
      if ((bntmp = ASN1_ENUMERATED_to_BN(a, NULL)) == NULL
          || (strtmp = BN_bn2dec(bntmp)) == NULL)
          X509V3err(X509V3_F_I2S_ASN1_ENUMERATED, ERR_R_MALLOC_FAILURE);
      BN_free(bntmp);
      return strtmp;
  }
  
  char *i2s_ASN1_INTEGER(X509V3_EXT_METHOD *method, ASN1_INTEGER *a)
  {
      BIGNUM *bntmp = NULL;
      char *strtmp = NULL;
  
      if (!a)
          return NULL;
      if ((bntmp = ASN1_INTEGER_to_BN(a, NULL)) == NULL
          || (strtmp = BN_bn2dec(bntmp)) == NULL)
          X509V3err(X509V3_F_I2S_ASN1_INTEGER, ERR_R_MALLOC_FAILURE);
      BN_free(bntmp);
      return strtmp;
  }
  
  ASN1_INTEGER *s2i_ASN1_INTEGER(X509V3_EXT_METHOD *method, char *value)
  {
      BIGNUM *bn = NULL;
      ASN1_INTEGER *aint;
      int isneg, ishex;
      int ret;
      if (value == NULL) {
          X509V3err(X509V3_F_S2I_ASN1_INTEGER, X509V3_R_INVALID_NULL_VALUE);
          return NULL;
      }
      bn = BN_new();
      if (bn == NULL) {
          X509V3err(X509V3_F_S2I_ASN1_INTEGER, ERR_R_MALLOC_FAILURE);
          return NULL;
      }
      if (value[0] == '-') {
          value++;
          isneg = 1;
      } else
          isneg = 0;
  
      if (value[0] == '0' && ((value[1] == 'x') || (value[1] == 'X'))) {
          value += 2;
          ishex = 1;
      } else
          ishex = 0;
  
      if (ishex)
          ret = BN_hex2bn(&bn, value);
      else
          ret = BN_dec2bn(&bn, value);
  
      if (!ret || value[ret]) {
          BN_free(bn);
          X509V3err(X509V3_F_S2I_ASN1_INTEGER, X509V3_R_BN_DEC2BN_ERROR);
          return NULL;
      }
  
      if (isneg && BN_is_zero(bn))
          isneg = 0;
  
      aint = BN_to_ASN1_INTEGER(bn, NULL);
      BN_free(bn);
      if (!aint) {
          X509V3err(X509V3_F_S2I_ASN1_INTEGER,
                    X509V3_R_BN_TO_ASN1_INTEGER_ERROR);
          return NULL;
      }
      if (isneg)
          aint->type |= V_ASN1_NEG;
      return aint;
  }
  
  int X509V3_add_value_int(const char *name, ASN1_INTEGER *aint,
                           STACK_OF(CONF_VALUE) **extlist)
  {
      char *strtmp;
      int ret;
  
      if (!aint)
          return 1;
      if ((strtmp = i2s_ASN1_INTEGER(NULL, aint)) == NULL)
          return 0;
      ret = X509V3_add_value(name, strtmp, extlist);
      OPENSSL_free(strtmp);
      return ret;
  }
  
  int X509V3_get_value_bool(CONF_VALUE *value, int *asn1_bool)
  {
      char *btmp;
  
      if ((btmp = value->value) == NULL)
          goto err;
      if (strcmp(btmp, "TRUE") == 0
          || strcmp(btmp, "true") == 0
          || strcmp(btmp, "Y") == 0
          || strcmp(btmp, "y") == 0
          || strcmp(btmp, "YES") == 0
          || strcmp(btmp, "yes") == 0) {
          *asn1_bool = 0xff;
          return 1;
      }
      if (strcmp(btmp, "FALSE") == 0
          || strcmp(btmp, "false") == 0
          || strcmp(btmp, "N") == 0
          || strcmp(btmp, "n") == 0
          || strcmp(btmp, "NO") == 0
          || strcmp(btmp, "no") == 0) {
          *asn1_bool = 0;
          return 1;
      }
   err:
      X509V3err(X509V3_F_X509V3_GET_VALUE_BOOL,
                X509V3_R_INVALID_BOOLEAN_STRING);
      X509V3_conf_err(value);
      return 0;
  }
  
  int X509V3_get_value_int(CONF_VALUE *value, ASN1_INTEGER **aint)
  {
      ASN1_INTEGER *itmp;
  
      if ((itmp = s2i_ASN1_INTEGER(NULL, value->value)) == NULL) {
          X509V3_conf_err(value);
          return 0;
      }
      *aint = itmp;
      return 1;
  }
  
  #define HDR_NAME        1
  #define HDR_VALUE       2
  
  /*
   * #define DEBUG
   */
  
  STACK_OF(CONF_VALUE) *X509V3_parse_list(const char *line)
  {
      char *p, *q, c;
      char *ntmp, *vtmp;
      STACK_OF(CONF_VALUE) *values = NULL;
      char *linebuf;
      int state;
      /* We are going to modify the line so copy it first */
      linebuf = OPENSSL_strdup(line);
      if (linebuf == NULL) {
          X509V3err(X509V3_F_X509V3_PARSE_LIST, ERR_R_MALLOC_FAILURE);
          goto err;
      }
      state = HDR_NAME;
      ntmp = NULL;
      /* Go through all characters */
      for (p = linebuf, q = linebuf; (c = *p) && (c != '\r') && (c != '\n');
           p++) {
  
          switch (state) {
          case HDR_NAME:
              if (c == ':') {
                  state = HDR_VALUE;
                  *p = 0;
                  ntmp = strip_spaces(q);
                  if (!ntmp) {
                      X509V3err(X509V3_F_X509V3_PARSE_LIST,
                                X509V3_R_INVALID_NULL_NAME);
                      goto err;
                  }
                  q = p + 1;
              } else if (c == ',') {
                  *p = 0;
                  ntmp = strip_spaces(q);
                  q = p + 1;
                  if (!ntmp) {
                      X509V3err(X509V3_F_X509V3_PARSE_LIST,
                                X509V3_R_INVALID_NULL_NAME);
                      goto err;
                  }
                  X509V3_add_value(ntmp, NULL, &values);
              }
              break;
  
          case HDR_VALUE:
              if (c == ',') {
                  state = HDR_NAME;
                  *p = 0;
                  vtmp = strip_spaces(q);
                  if (!vtmp) {
                      X509V3err(X509V3_F_X509V3_PARSE_LIST,
                                X509V3_R_INVALID_NULL_VALUE);
                      goto err;
                  }
                  X509V3_add_value(ntmp, vtmp, &values);
                  ntmp = NULL;
                  q = p + 1;
              }
  
          }
      }
  
      if (state == HDR_VALUE) {
          vtmp = strip_spaces(q);
          if (!vtmp) {
              X509V3err(X509V3_F_X509V3_PARSE_LIST,
                        X509V3_R_INVALID_NULL_VALUE);
              goto err;
          }
          X509V3_add_value(ntmp, vtmp, &values);
      } else {
          ntmp = strip_spaces(q);
          if (!ntmp) {
              X509V3err(X509V3_F_X509V3_PARSE_LIST, X509V3_R_INVALID_NULL_NAME);
              goto err;
          }
          X509V3_add_value(ntmp, NULL, &values);
      }
      OPENSSL_free(linebuf);
      return values;
  
   err:
      OPENSSL_free(linebuf);
      sk_CONF_VALUE_pop_free(values, X509V3_conf_free);
      return NULL;
  
  }
  
  /* Delete leading and trailing spaces from a string */
  static char *strip_spaces(char *name)
  {
      char *p, *q;
      /* Skip over leading spaces */
      p = name;
      while (*p && isspace((unsigned char)*p))
          p++;
      if (!*p)
          return NULL;
      q = p + strlen(p) - 1;
      while ((q != p) && isspace((unsigned char)*q))
          q--;
      if (p != q)
          q[1] = 0;
      if (!*p)
          return NULL;
      return p;
  }
  
  /* hex string utilities */
  
  /*
   * Given a buffer of length 'len' return a OPENSSL_malloc'ed string with its
   * hex representation @@@ (Contents of buffer are always kept in ASCII, also
   * on EBCDIC machines)
   */
  
  char *hex_to_string(const unsigned char *buffer, long len)
  {
      char *tmp, *q;
      const unsigned char *p;
      int i;
      const static char hexdig[] = "0123456789ABCDEF";
      if (!buffer || !len)
          return NULL;
      if ((tmp = OPENSSL_malloc(len * 3 + 1)) == NULL) {
          X509V3err(X509V3_F_HEX_TO_STRING, ERR_R_MALLOC_FAILURE);
          return NULL;
      }
      q = tmp;
      for (i = 0, p = buffer; i < len; i++, p++) {
          *q++ = hexdig[(*p >> 4) & 0xf];
          *q++ = hexdig[*p & 0xf];
          *q++ = ':';
      }
      q[-1] = 0;
  #ifdef CHARSET_EBCDIC
      ebcdic2ascii(tmp, tmp, q - tmp - 1);
  #endif
  
      return tmp;
  }
  
  /*
   * Give a string of hex digits convert to a buffer
   */
  
  unsigned char *string_to_hex(const char *str, long *len)
  {
      unsigned char *hexbuf, *q;
      unsigned char ch, cl, *p;
      if (!str) {
          X509V3err(X509V3_F_STRING_TO_HEX, X509V3_R_INVALID_NULL_ARGUMENT);
          return NULL;
      }
      if ((hexbuf = OPENSSL_malloc(strlen(str) >> 1)) == NULL)
          goto err;
      for (p = (unsigned char *)str, q = hexbuf; *p;) {
          ch = *p++;
  #ifdef CHARSET_EBCDIC
          ch = os_toebcdic[ch];
  #endif
          if (ch == ':')
              continue;
          cl = *p++;
  #ifdef CHARSET_EBCDIC
          cl = os_toebcdic[cl];
  #endif
          if (!cl) {
              X509V3err(X509V3_F_STRING_TO_HEX, X509V3_R_ODD_NUMBER_OF_DIGITS);
              OPENSSL_free(hexbuf);
              return NULL;
          }
          if (isupper(ch))
              ch = tolower(ch);
          if (isupper(cl))
              cl = tolower(cl);
  
          if ((ch >= '0') && (ch <= '9'))
              ch -= '0';
          else if ((ch >= 'a') && (ch <= 'f'))
              ch -= 'a' - 10;
          else
              goto badhex;
  
          if ((cl >= '0') && (cl <= '9'))
              cl -= '0';
          else if ((cl >= 'a') && (cl <= 'f'))
              cl -= 'a' - 10;
          else
              goto badhex;
  
          *q++ = (ch << 4) | cl;
      }
  
      if (len)
          *len = q - hexbuf;
  
      return hexbuf;
  
   err:
      OPENSSL_free(hexbuf);
      X509V3err(X509V3_F_STRING_TO_HEX, ERR_R_MALLOC_FAILURE);
      return NULL;
  
   badhex:
      OPENSSL_free(hexbuf);
      X509V3err(X509V3_F_STRING_TO_HEX, X509V3_R_ILLEGAL_HEX_DIGIT);
      return NULL;
  
  }
  
  /*
   * V2I name comparison function: returns zero if 'name' matches cmp or cmp.*
   */
  
  int name_cmp(const char *name, const char *cmp)
  {
      int len, ret;
      char c;
      len = strlen(cmp);
      if ((ret = strncmp(name, cmp, len)))
          return ret;
      c = name[len];
      if (!c || (c == '.'))
          return 0;
      return 1;
  }
  
  static int sk_strcmp(const char *const *a, const char *const *b)
  {
      return strcmp(*a, *b);
  }
  
  STACK_OF(OPENSSL_STRING) *X509_get1_email(X509 *x)
  {
      GENERAL_NAMES *gens;
      STACK_OF(OPENSSL_STRING) *ret;
  
      gens = X509_get_ext_d2i(x, NID_subject_alt_name, NULL, NULL);
      ret = get_email(X509_get_subject_name(x), gens);
      sk_GENERAL_NAME_pop_free(gens, GENERAL_NAME_free);
      return ret;
  }
  
  STACK_OF(OPENSSL_STRING) *X509_get1_ocsp(X509 *x)
  {
      AUTHORITY_INFO_ACCESS *info;
      STACK_OF(OPENSSL_STRING) *ret = NULL;
      int i;
  
      info = X509_get_ext_d2i(x, NID_info_access, NULL, NULL);
      if (!info)
          return NULL;
      for (i = 0; i < sk_ACCESS_DESCRIPTION_num(info); i++) {
          ACCESS_DESCRIPTION *ad = sk_ACCESS_DESCRIPTION_value(info, i);
          if (OBJ_obj2nid(ad->method) == NID_ad_OCSP) {
              if (ad->location->type == GEN_URI) {
                  if (!append_ia5
                      (&ret, ad->location->d.uniformResourceIdentifier))
                      break;
              }
          }
      }
      AUTHORITY_INFO_ACCESS_free(info);
      return ret;
  }
  
  STACK_OF(OPENSSL_STRING) *X509_REQ_get1_email(X509_REQ *x)
  {
      GENERAL_NAMES *gens;
      STACK_OF(X509_EXTENSION) *exts;
      STACK_OF(OPENSSL_STRING) *ret;
  
      exts = X509_REQ_get_extensions(x);
      gens = X509V3_get_d2i(exts, NID_subject_alt_name, NULL, NULL);
      ret = get_email(X509_REQ_get_subject_name(x), gens);
      sk_GENERAL_NAME_pop_free(gens, GENERAL_NAME_free);
      sk_X509_EXTENSION_pop_free(exts, X509_EXTENSION_free);
      return ret;
  }
  
  static STACK_OF(OPENSSL_STRING) *get_email(X509_NAME *name,
                                             GENERAL_NAMES *gens)
  {
      STACK_OF(OPENSSL_STRING) *ret = NULL;
      X509_NAME_ENTRY *ne;
      ASN1_IA5STRING *email;
      GENERAL_NAME *gen;
      int i;
      /* Now add any email address(es) to STACK */
      i = -1;
      /* First supplied X509_NAME */
      while ((i = X509_NAME_get_index_by_NID(name,
                                             NID_pkcs9_emailAddress, i)) >= 0) {
          ne = X509_NAME_get_entry(name, i);
          email = X509_NAME_ENTRY_get_data(ne);
          if (!append_ia5(&ret, email))
              return NULL;
      }
      for (i = 0; i < sk_GENERAL_NAME_num(gens); i++) {
          gen = sk_GENERAL_NAME_value(gens, i);
          if (gen->type != GEN_EMAIL)
              continue;
          if (!append_ia5(&ret, gen->d.ia5))
              return NULL;
      }
      return ret;
  }
  
  static void str_free(OPENSSL_STRING str)
  {
      OPENSSL_free(str);
  }
  
  static int append_ia5(STACK_OF(OPENSSL_STRING) **sk, ASN1_IA5STRING *email)
  {
      char *emtmp;
      /* First some sanity checks */
      if (email->type != V_ASN1_IA5STRING)
          return 1;
      if (!email->data || !email->length)
          return 1;
      if (*sk == NULL)
          *sk = sk_OPENSSL_STRING_new(sk_strcmp);
      if (*sk == NULL)
          return 0;
      /* Don't add duplicates */
      if (sk_OPENSSL_STRING_find(*sk, (char *)email->data) != -1)
          return 1;
      emtmp = OPENSSL_strdup((char *)email->data);
      if (emtmp == NULL || !sk_OPENSSL_STRING_push(*sk, emtmp)) {
          X509_email_free(*sk);
          *sk = NULL;
          return 0;
      }
      return 1;
  }
  
  void X509_email_free(STACK_OF(OPENSSL_STRING) *sk)
  {
      sk_OPENSSL_STRING_pop_free(sk, str_free);
  }
  
  typedef int (*equal_fn) (const unsigned char *pattern, size_t pattern_len,
                           const unsigned char *subject, size_t subject_len,
                           unsigned int flags);
  
  /* Skip pattern prefix to match "wildcard" subject */
  static void skip_prefix(const unsigned char **p, size_t *plen,
                          size_t subject_len,
                          unsigned int flags)
  {
      const unsigned char *pattern = *p;
      size_t pattern_len = *plen;
  
      /*
       * If subject starts with a leading '.' followed by more octets, and
       * pattern is longer, compare just an equal-length suffix with the
       * full subject (starting at the '.'), provided the prefix contains
       * no NULs.
       */
      if ((flags & _X509_CHECK_FLAG_DOT_SUBDOMAINS) == 0)
          return;
  
      while (pattern_len > subject_len && *pattern) {
          if ((flags & X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS) &&
              *pattern == '.')
              break;
          ++pattern;
          --pattern_len;
      }
  
      /* Skip if entire prefix acceptable */
      if (pattern_len == subject_len) {
          *p = pattern;
          *plen = pattern_len;
      }
  }
  
  /* Compare while ASCII ignoring case. */
  static int equal_nocase(const unsigned char *pattern, size_t pattern_len,
                          const unsigned char *subject, size_t subject_len,
                          unsigned int flags)
  {
      skip_prefix(&pattern, &pattern_len, subject_len, flags);
      if (pattern_len != subject_len)
          return 0;
      while (pattern_len) {
          unsigned char l = *pattern;
          unsigned char r = *subject;
          /* The pattern must not contain NUL characters. */
          if (l == 0)
              return 0;
          if (l != r) {
              if ('A' <= l && l <= 'Z')
                  l = (l - 'A') + 'a';
              if ('A' <= r && r <= 'Z')
                  r = (r - 'A') + 'a';
              if (l != r)
                  return 0;
          }
          ++pattern;
          ++subject;
          --pattern_len;
      }
      return 1;
  }
  
  /* Compare using memcmp. */
  static int equal_case(const unsigned char *pattern, size_t pattern_len,
                        const unsigned char *subject, size_t subject_len,
                        unsigned int flags)
  {
      skip_prefix(&pattern, &pattern_len, subject_len, flags);
      if (pattern_len != subject_len)
          return 0;
      return !memcmp(pattern, subject, pattern_len);
  }
  
  /*
   * RFC 5280, section 7.5, requires that only the domain is compared in a
   * case-insensitive manner.
   */
  static int equal_email(const unsigned char *a, size_t a_len,
                         const unsigned char *b, size_t b_len,
                         unsigned int unused_flags)
  {
      size_t i = a_len;
      if (a_len != b_len)
          return 0;
      /*
       * We search backwards for the '@' character, so that we do not have to
       * deal with quoted local-parts.  The domain part is compared in a
       * case-insensitive manner.
       */
      while (i > 0) {
          --i;
          if (a[i] == '@' || b[i] == '@') {
              if (!equal_nocase(a + i, a_len - i, b + i, a_len - i, 0))
                  return 0;
              break;
          }
      }
      if (i == 0)
          i = a_len;
      return equal_case(a, i, b, i, 0);
  }
  
  /*
   * Compare the prefix and suffix with the subject, and check that the
   * characters in-between are valid.
   */
  static int wildcard_match(const unsigned char *prefix, size_t prefix_len,
                            const unsigned char *suffix, size_t suffix_len,
                            const unsigned char *subject, size_t subject_len,
                            unsigned int flags)
  {
      const unsigned char *wildcard_start;
      const unsigned char *wildcard_end;
      const unsigned char *p;
      int allow_multi = 0;
      int allow_idna = 0;
  
      if (subject_len < prefix_len + suffix_len)
          return 0;
      if (!equal_nocase(prefix, prefix_len, subject, prefix_len, flags))
          return 0;
      wildcard_start = subject + prefix_len;
      wildcard_end = subject + (subject_len - suffix_len);
      if (!equal_nocase(wildcard_end, suffix_len, suffix, suffix_len, flags))
          return 0;
      /*
       * If the wildcard makes up the entire first label, it must match at
       * least one character.
       */
      if (prefix_len == 0 && *suffix == '.') {
          if (wildcard_start == wildcard_end)
              return 0;
          allow_idna = 1;
          if (flags & X509_CHECK_FLAG_MULTI_LABEL_WILDCARDS)
              allow_multi = 1;
      }
      /* IDNA labels cannot match partial wildcards */
      if (!allow_idna &&
          subject_len >= 4 && strncasecmp((char *)subject, "xn--", 4) == 0)
          return 0;
      /* The wildcard may match a literal '*' */
      if (wildcard_end == wildcard_start + 1 && *wildcard_start == '*')
          return 1;
      /*
       * Check that the part matched by the wildcard contains only
       * permitted characters and only matches a single label unless
       * allow_multi is set.
       */
      for (p = wildcard_start; p != wildcard_end; ++p)
          if (!(('0' <= *p && *p <= '9') ||
                ('A' <= *p && *p <= 'Z') ||
                ('a' <= *p && *p <= 'z') ||
                *p == '-' || (allow_multi && *p == '.')))
              return 0;
      return 1;
  }
  
  #define LABEL_START     (1 << 0)
  #define LABEL_END       (1 << 1)
  #define LABEL_HYPHEN    (1 << 2)
  #define LABEL_IDNA      (1 << 3)
  
  static const unsigned char *valid_star(const unsigned char *p, size_t len,
                                         unsigned int flags)
  {
      const unsigned char *star = 0;
      size_t i;
      int state = LABEL_START;
      int dots = 0;
      for (i = 0; i < len; ++i) {
          /*
           * Locate first and only legal wildcard, either at the start
           * or end of a non-IDNA first and not final label.
           */
          if (p[i] == '*') {
              int atstart = (state & LABEL_START);
              int atend = (i == len - 1 || p[i + 1] == '.');
              /*-
               * At most one wildcard per pattern.
               * No wildcards in IDNA labels.
               * No wildcards after the first label.
               */
              if (star != NULL || (state & LABEL_IDNA) != 0 || dots)
                  return NULL;
              /* Only full-label '*.example.com' wildcards? */
              if ((flags & X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS)
                  && (!atstart || !atend))
                  return NULL;
              /* No 'foo*bar' wildcards */
              if (!atstart && !atend)
                  return NULL;
              star = &p[i];
              state &= ~LABEL_START;
          } else if (('a' <= p[i] && p[i] <= 'z')
                     || ('A' <= p[i] && p[i] <= 'Z')
                     || ('0' <= p[i] && p[i] <= '9')) {
              if ((state & LABEL_START) != 0
                  && len - i >= 4 && strncasecmp((char *)&p[i], "xn--", 4) == 0)
                  state |= LABEL_IDNA;
              state &= ~(LABEL_HYPHEN | LABEL_START);
          } else if (p[i] == '.') {
              if ((state & (LABEL_HYPHEN | LABEL_START)) != 0)
                  return NULL;
              state = LABEL_START;
              ++dots;
          } else if (p[i] == '-') {
              /* no domain/subdomain starts with '-' */
              if ((state & LABEL_START) != 0)
                  return NULL;
              state |= LABEL_HYPHEN;
          } else
              return NULL;
      }
  
      /*
       * The final label must not end in a hyphen or ".", and
       * there must be at least two dots after the star.
       */
      if ((state & (LABEL_START | LABEL_HYPHEN)) != 0 || dots < 2)
          return NULL;
      return star;
  }
  
  /* Compare using wildcards. */
  static int equal_wildcard(const unsigned char *pattern, size_t pattern_len,
                            const unsigned char *subject, size_t subject_len,
                            unsigned int flags)
  {
      const unsigned char *star = NULL;
  
      /*
       * Subject names starting with '.' can only match a wildcard pattern
       * via a subject sub-domain pattern suffix match.
       */
      if (!(subject_len > 1 && subject[0] == '.'))
          star = valid_star(pattern, pattern_len, flags);
      if (star == NULL)
          return equal_nocase(pattern, pattern_len,
                              subject, subject_len, flags);
      return wildcard_match(pattern, star - pattern,
                            star + 1, (pattern + pattern_len) - star - 1,
                            subject, subject_len, flags);
  }
  
  /*
   * Compare an ASN1_STRING to a supplied string. If they match return 1. If
   * cmp_type > 0 only compare if string matches the type, otherwise convert it
   * to UTF8.
   */
  
  static int do_check_string(ASN1_STRING *a, int cmp_type, equal_fn equal,
                             unsigned int flags, const char *b, size_t blen,
                             char **peername)
  {
      int rv = 0;
  
      if (!a->data || !a->length)
          return 0;
      if (cmp_type > 0) {
          if (cmp_type != a->type)
              return 0;
          if (cmp_type == V_ASN1_IA5STRING)
              rv = equal(a->data, a->length, (unsigned char *)b, blen, flags);
          else if (a->length == (int)blen && !memcmp(a->data, b, blen))
              rv = 1;
          if (rv > 0 && peername)
              *peername = OPENSSL_strndup((char *)a->data, a->length);
      } else {
          int astrlen;
          unsigned char *astr;
          astrlen = ASN1_STRING_to_UTF8(&astr, a);
          if (astrlen < 0) {
              /*
               * -1 could be an internal malloc failure or a decoding error from
               * malformed input; we can't distinguish.
               */
              return -1;
          }
          rv = equal(astr, astrlen, (unsigned char *)b, blen, flags);
          if (rv > 0 && peername)
              *peername = OPENSSL_strndup((char *)astr, astrlen);
          OPENSSL_free(astr);
      }
      return rv;
  }
  
  static int do_x509_check(X509 *x, const char *chk, size_t chklen,
                           unsigned int flags, int check_type, char **peername)
  {
      GENERAL_NAMES *gens = NULL;
      X509_NAME *name = NULL;
      int i;
      int cnid = NID_undef;
      int alt_type;
      int san_present = 0;
      int rv = 0;
      equal_fn equal;
  
      /* See below, this flag is internal-only */
      flags &= ~_X509_CHECK_FLAG_DOT_SUBDOMAINS;
      if (check_type == GEN_EMAIL) {
          cnid = NID_pkcs9_emailAddress;
          alt_type = V_ASN1_IA5STRING;
          equal = equal_email;
      } else if (check_type == GEN_DNS) {
          cnid = NID_commonName;
          /* Implicit client-side DNS sub-domain pattern */
          if (chklen > 1 && chk[0] == '.')
              flags |= _X509_CHECK_FLAG_DOT_SUBDOMAINS;
          alt_type = V_ASN1_IA5STRING;
          if (flags & X509_CHECK_FLAG_NO_WILDCARDS)
              equal = equal_nocase;
          else
              equal = equal_wildcard;
      } else {
          alt_type = V_ASN1_OCTET_STRING;
          equal = equal_case;
      }
  
      if (chklen == 0)
          chklen = strlen(chk);
  
      gens = X509_get_ext_d2i(x, NID_subject_alt_name, NULL, NULL);
      if (gens) {
          for (i = 0; i < sk_GENERAL_NAME_num(gens); i++) {
              GENERAL_NAME *gen;
              ASN1_STRING *cstr;
              gen = sk_GENERAL_NAME_value(gens, i);
              if (gen->type != check_type)
                  continue;
              san_present = 1;
              if (check_type == GEN_EMAIL)
                  cstr = gen->d.rfc822Name;
              else if (check_type == GEN_DNS)
                  cstr = gen->d.dNSName;
              else
                  cstr = gen->d.iPAddress;
              /* Positive on success, negative on error! */
              if ((rv = do_check_string(cstr, alt_type, equal, flags,
                                        chk, chklen, peername)) != 0)
                  break;
          }
          GENERAL_NAMES_free(gens);
          if (rv != 0)
              return rv;
          if (cnid == NID_undef
              || (san_present
                  && !(flags & X509_CHECK_FLAG_ALWAYS_CHECK_SUBJECT)))
              return 0;
      }
  
      /* We're done if CN-ID is not pertinent */
      if (cnid == NID_undef)
          return 0;
  
      i = -1;
      name = X509_get_subject_name(x);
      while ((i = X509_NAME_get_index_by_NID(name, cnid, i)) >= 0) {
          X509_NAME_ENTRY *ne;
          ASN1_STRING *str;
          ne = X509_NAME_get_entry(name, i);
          str = X509_NAME_ENTRY_get_data(ne);
          /* Positive on success, negative on error! */
          if ((rv = do_check_string(str, -1, equal, flags,
                                    chk, chklen, peername)) != 0)
              return rv;
      }
      return 0;
  }
  
  int X509_check_host(X509 *x, const char *chk, size_t chklen,
                      unsigned int flags, char **peername)
  {
      if (chk == NULL)
          return -2;
      /*
       * Embedded NULs are disallowed, except as the last character of a
       * string of length 2 or more (tolerate caller including terminating
       * NUL in string length).
       */
      if (chklen == 0)
          chklen = strlen(chk);
      else if (memchr(chk, '\0', chklen > 1 ? chklen - 1 : chklen))
          return -2;
      if (chklen > 1 && chk[chklen - 1] == '\0')
          --chklen;
      return do_x509_check(x, chk, chklen, flags, GEN_DNS, peername);
  }
  
  int X509_check_email(X509 *x, const char *chk, size_t chklen,
                       unsigned int flags)
  {
      if (chk == NULL)
          return -2;
      /*
       * Embedded NULs are disallowed, except as the last character of a
       * string of length 2 or more (tolerate caller including terminating
       * NUL in string length).
       */
      if (chklen == 0)
          chklen = strlen((char *)chk);
      else if (memchr(chk, '\0', chklen > 1 ? chklen - 1 : chklen))
          return -2;
      if (chklen > 1 && chk[chklen - 1] == '\0')
          --chklen;
      return do_x509_check(x, chk, chklen, flags, GEN_EMAIL, NULL);
  }
  
  int X509_check_ip(X509 *x, const unsigned char *chk, size_t chklen,
                    unsigned int flags)
  {
      if (chk == NULL)
          return -2;
      return do_x509_check(x, (char *)chk, chklen, flags, GEN_IPADD, NULL);
  }
  
  int X509_check_ip_asc(X509 *x, const char *ipasc, unsigned int flags)
  {
      unsigned char ipout[16];
      size_t iplen;
  
      if (ipasc == NULL)
          return -2;
      iplen = (size_t)a2i_ipadd(ipout, ipasc);
      if (iplen == 0)
          return -2;
      return do_x509_check(x, (char *)ipout, iplen, flags, GEN_IPADD, NULL);
  }
  
  /*
   * Convert IP addresses both IPv4 and IPv6 into an OCTET STRING compatible
   * with RFC3280.
   */
  
  ASN1_OCTET_STRING *a2i_IPADDRESS(const char *ipasc)
  {
      unsigned char ipout[16];
      ASN1_OCTET_STRING *ret;
      int iplen;
  
      /* If string contains a ':' assume IPv6 */
  
      iplen = a2i_ipadd(ipout, ipasc);
  
      if (!iplen)
          return NULL;
  
      ret = ASN1_OCTET_STRING_new();
      if (ret == NULL)
          return NULL;
      if (!ASN1_OCTET_STRING_set(ret, ipout, iplen)) {
          ASN1_OCTET_STRING_free(ret);
          return NULL;
      }
      return ret;
  }
  
  ASN1_OCTET_STRING *a2i_IPADDRESS_NC(const char *ipasc)
  {
      ASN1_OCTET_STRING *ret = NULL;
      unsigned char ipout[32];
      char *iptmp = NULL, *p;
      int iplen1, iplen2;
      p = strchr(ipasc, '/');
      if (!p)
          return NULL;
      iptmp = OPENSSL_strdup(ipasc);
      if (!iptmp)
          return NULL;
      p = iptmp + (p - ipasc);
      *p++ = 0;
  
      iplen1 = a2i_ipadd(ipout, iptmp);
  
      if (!iplen1)
          goto err;
  
      iplen2 = a2i_ipadd(ipout + iplen1, p);
  
      OPENSSL_free(iptmp);
      iptmp = NULL;
  
      if (!iplen2 || (iplen1 != iplen2))
          goto err;
  
      ret = ASN1_OCTET_STRING_new();
      if (ret == NULL)
          goto err;
      if (!ASN1_OCTET_STRING_set(ret, ipout, iplen1 + iplen2))
          goto err;
  
      return ret;
  
   err:
      OPENSSL_free(iptmp);
      ASN1_OCTET_STRING_free(ret);
      return NULL;
  }
  
  int a2i_ipadd(unsigned char *ipout, const char *ipasc)
  {
      /* If string contains a ':' assume IPv6 */
  
      if (strchr(ipasc, ':')) {
          if (!ipv6_from_asc(ipout, ipasc))
              return 0;
          return 16;
      } else {
          if (!ipv4_from_asc(ipout, ipasc))
              return 0;
          return 4;
      }
  }
  
  static int ipv4_from_asc(unsigned char *v4, const char *in)
  {
      int a0, a1, a2, a3;
      if (sscanf(in, "%d.%d.%d.%d", &a0, &a1, &a2, &a3) != 4)
          return 0;
      if ((a0 < 0) || (a0 > 255) || (a1 < 0) || (a1 > 255)
          || (a2 < 0) || (a2 > 255) || (a3 < 0) || (a3 > 255))
          return 0;
      v4[0] = a0;
      v4[1] = a1;
      v4[2] = a2;
      v4[3] = a3;
      return 1;
  }
  
  typedef struct {
      /* Temporary store for IPV6 output */
      unsigned char tmp[16];
      /* Total number of bytes in tmp */
      int total;
      /* The position of a zero (corresponding to '::') */
      int zero_pos;
      /* Number of zeroes */
      int zero_cnt;
  } IPV6_STAT;
  
  static int ipv6_from_asc(unsigned char *v6, const char *in)
  {
      IPV6_STAT v6stat;
      v6stat.total = 0;
      v6stat.zero_pos = -1;
      v6stat.zero_cnt = 0;
      /*
       * Treat the IPv6 representation as a list of values separated by ':'.
       * The presence of a '::' will parse as one, two or three zero length
       * elements.
       */
      if (!CONF_parse_list(in, ':', 0, ipv6_cb, &v6stat))
          return 0;
  
      /* Now for some sanity checks */
  
      if (v6stat.zero_pos == -1) {
          /* If no '::' must have exactly 16 bytes */
          if (v6stat.total != 16)
              return 0;
      } else {
          /* If '::' must have less than 16 bytes */
          if (v6stat.total == 16)
              return 0;
          /* More than three zeroes is an error */
          if (v6stat.zero_cnt > 3)
              return 0;
          /* Can only have three zeroes if nothing else present */
          else if (v6stat.zero_cnt == 3) {
              if (v6stat.total > 0)
                  return 0;
          }
          /* Can only have two zeroes if at start or end */
          else if (v6stat.zero_cnt == 2) {
              if ((v6stat.zero_pos != 0)
                  && (v6stat.zero_pos != v6stat.total))
                  return 0;
          } else
              /* Can only have one zero if *not* start or end */
          {
              if ((v6stat.zero_pos == 0)
                  || (v6stat.zero_pos == v6stat.total))
                  return 0;
          }
      }
  
      /* Format result */
  
      if (v6stat.zero_pos >= 0) {
          /* Copy initial part */
          memcpy(v6, v6stat.tmp, v6stat.zero_pos);
          /* Zero middle */
          memset(v6 + v6stat.zero_pos, 0, 16 - v6stat.total);
          /* Copy final part */
          if (v6stat.total != v6stat.zero_pos)
              memcpy(v6 + v6stat.zero_pos + 16 - v6stat.total,
                     v6stat.tmp + v6stat.zero_pos,
                     v6stat.total - v6stat.zero_pos);
      } else
          memcpy(v6, v6stat.tmp, 16);
  
      return 1;
  }
  
  static int ipv6_cb(const char *elem, int len, void *usr)
  {
      IPV6_STAT *s = usr;
      /* Error if 16 bytes written */
      if (s->total == 16)
          return 0;
      if (len == 0) {
          /* Zero length element, corresponds to '::' */
          if (s->zero_pos == -1)
              s->zero_pos = s->total;
          /* If we've already got a :: its an error */
          else if (s->zero_pos != s->total)
              return 0;
          s->zero_cnt++;
      } else {
          /* If more than 4 characters could be final a.b.c.d form */
          if (len > 4) {
              /* Need at least 4 bytes left */
              if (s->total > 12)
                  return 0;
              /* Must be end of string */
              if (elem[len])
                  return 0;
              if (!ipv4_from_asc(s->tmp + s->total, elem))
                  return 0;
              s->total += 4;
          } else {
              if (!ipv6_hex(s->tmp + s->total, elem, len))
                  return 0;
              s->total += 2;
          }
      }
      return 1;
  }
  
  /*
   * Convert a string of up to 4 hex digits into the corresponding IPv6 form.
   */
  
  static int ipv6_hex(unsigned char *out, const char *in, int inlen)
  {
      unsigned char c;
      unsigned int num = 0;
      if (inlen > 4)
          return 0;
      while (inlen--) {
          c = *in++;
          num <<= 4;
          if ((c >= '0') && (c <= '9'))
              num |= c - '0';
          else if ((c >= 'A') && (c <= 'F'))
              num |= c - 'A' + 10;
          else if ((c >= 'a') && (c <= 'f'))
              num |= c - 'a' + 10;
          else
              return 0;
      }
      out[0] = num >> 8;
      out[1] = num & 0xff;
      return 1;
  }
  
  int X509V3_NAME_from_section(X509_NAME *nm, STACK_OF(CONF_VALUE) *dn_sk,
                               unsigned long chtype)
  {
      CONF_VALUE *v;
      int i, mval, spec_char, plus_char;
      char *p, *type;
      if (!nm)
          return 0;
  
      for (i = 0; i < sk_CONF_VALUE_num(dn_sk); i++) {
          v = sk_CONF_VALUE_value(dn_sk, i);
          type = v->name;
          /*
           * Skip past any leading X. X: X, etc to allow for multiple instances
           */
          for (p = type; *p; p++) {
  #ifndef CHARSET_EBCDIC
              spec_char = ((*p == ':') || (*p == ',') || (*p == '.'));
  #else
              spec_char = ((*p == os_toascii[':']) || (*p == os_toascii[','])
                      || (*p == os_toascii['.']));
  #endif
              if (spec_char) {
                  p++;
                  if (*p)
                      type = p;
                  break;
              }
          }
  #ifndef CHARSET_EBCDIC
          plus_char = (*type == '+');
  #else
          plus_char = (*type == os_toascii['+']);
  #endif
          if (plus_char) {
              mval = -1;
              type++;
          } else
              mval = 0;
          if (!X509_NAME_add_entry_by_txt(nm, type, chtype,
                                          (unsigned char *)v->value, -1, -1,
                                          mval))
              return 0;
  
      }
      return 1;
  }
  