text: /*
   * Copyright 2006-2020 The OpenSSL Project Authors. All Rights Reserved.
   *
   * Licensed under the Apache License 2.0 (the "License").  You may not use
   * this file except in compliance with the License.  You can obtain a copy
   * in the file LICENSE in the source distribution or at
   * https://www.openssl.org/source/license.html
   */
  
  /*
   * Implementation of RFC 3779 section 2.2.
   */
  
  #include <stdio.h>
  #include <stdlib.h>
  
  #include "internal/cryptlib.h"
  #include <openssl/conf.h>
  #include <openssl/asn1.h>
  #include <openssl/asn1t.h>
  #include <openssl/buffer.h>
  #include <openssl/x509v3.h>
  #include "crypto/x509.h"
  #include "ext_dat.h"
  #include "x509_local.h"
  
  #ifndef OPENSSL_NO_RFC3779
  
  /*
   * OpenSSL ASN.1 template translation of RFC 3779 2.2.3.
   */
  
  ASN1_SEQUENCE(IPAddressRange) = {
    ASN1_SIMPLE(IPAddressRange, min, ASN1_BIT_STRING),
    ASN1_SIMPLE(IPAddressRange, max, ASN1_BIT_STRING)
  } ASN1_SEQUENCE_END(IPAddressRange)
  
  ASN1_CHOICE(IPAddressOrRange) = {
    ASN1_SIMPLE(IPAddressOrRange, u.addressPrefix, ASN1_BIT_STRING),
    ASN1_SIMPLE(IPAddressOrRange, u.addressRange,  IPAddressRange)
  } ASN1_CHOICE_END(IPAddressOrRange)
  
  ASN1_CHOICE(IPAddressChoice) = {
    ASN1_SIMPLE(IPAddressChoice,      u.inherit,           ASN1_NULL),
    ASN1_SEQUENCE_OF(IPAddressChoice, u.addressesOrRanges, IPAddressOrRange)
  } ASN1_CHOICE_END(IPAddressChoice)
  
  ASN1_SEQUENCE(IPAddressFamily) = {
    ASN1_SIMPLE(IPAddressFamily, addressFamily,   ASN1_OCTET_STRING),
    ASN1_SIMPLE(IPAddressFamily, ipAddressChoice, IPAddressChoice)
  } ASN1_SEQUENCE_END(IPAddressFamily)
  
  ASN1_ITEM_TEMPLATE(IPAddrBlocks) =
    ASN1_EX_TEMPLATE_TYPE(ASN1_TFLG_SEQUENCE_OF, 0,
                          IPAddrBlocks, IPAddressFamily)
  static_ASN1_ITEM_TEMPLATE_END(IPAddrBlocks)
  
  IMPLEMENT_ASN1_FUNCTIONS(IPAddressRange)
  IMPLEMENT_ASN1_FUNCTIONS(IPAddressOrRange)
  IMPLEMENT_ASN1_FUNCTIONS(IPAddressChoice)
  IMPLEMENT_ASN1_FUNCTIONS(IPAddressFamily)
  
  /*
   * How much buffer space do we need for a raw address?
   */
  #define ADDR_RAW_BUF_LEN        16
  
  /*
   * What's the address length associated with this AFI?
   */
  static int length_from_afi(const unsigned afi)
  {
      switch (afi) {
      case IANA_AFI_IPV4:
          return 4;
      case IANA_AFI_IPV6:
          return 16;
      default:
          return 0;
      }
  }
  
  /*
   * Extract the AFI from an IPAddressFamily.
   */
  unsigned int X509v3_addr_get_afi(const IPAddressFamily *f)
  {
      if (f == NULL
              || f->addressFamily == NULL
              || f->addressFamily->data == NULL
              || f->addressFamily->length < 2)
          return 0;
      return (f->addressFamily->data[0] << 8) | f->addressFamily->data[1];
  }
  
  /*
   * Expand the bitstring form of an address into a raw byte array.
   * At the moment this is coded for simplicity, not speed.
   */
  static int addr_expand(unsigned char *addr,
                         const ASN1_BIT_STRING *bs,
                         const int length, const unsigned char fill)
  {
      if (bs->length < 0 || bs->length > length)
          return 0;
      if (bs->length > 0) {
          memcpy(addr, bs->data, bs->length);
          if ((bs->flags & 7) != 0) {
              unsigned char mask = 0xFF >> (8 - (bs->flags & 7));
              if (fill == 0)
                  addr[bs->length - 1] &= ~mask;
              else
                  addr[bs->length - 1] |= mask;
          }
      }
      memset(addr + bs->length, fill, length - bs->length);
      return 1;
  }
  
  /*
   * Extract the prefix length from a bitstring.
   */
  #define addr_prefixlen(bs) ((int) ((bs)->length * 8 - ((bs)->flags & 7)))
  
  /*
   * i2r handler for one address bitstring.
   */
  static int i2r_address(BIO *out,
                         const unsigned afi,
                         const unsigned char fill, const ASN1_BIT_STRING *bs)
  {
      unsigned char addr[ADDR_RAW_BUF_LEN];
      int i, n;
  
      if (bs->length < 0)
          return 0;
      switch (afi) {
      case IANA_AFI_IPV4:
          if (!addr_expand(addr, bs, 4, fill))
              return 0;
          BIO_printf(out, "%d.%d.%d.%d", addr[0], addr[1], addr[2], addr[3]);
          break;
          /* TODO possibly combine with ipaddr_to_asc() */
      case IANA_AFI_IPV6:
          if (!addr_expand(addr, bs, 16, fill))
              return 0;
          for (n = 16; n > 1 && addr[n - 1] == 0x00 && addr[n - 2] == 0x00;
               n -= 2) ;
          for (i = 0; i < n; i += 2)
              BIO_printf(out, "%x%s", (addr[i] << 8) | addr[i + 1],
                         (i < 14 ? ":" : ""));
          if (i < 16)
              BIO_puts(out, ":");
          if (i == 0)
              BIO_puts(out, ":");
          break;
      default:
          for (i = 0; i < bs->length; i++)
              BIO_printf(out, "%s%02x", (i > 0 ? ":" : ""), bs->data[i]);
          BIO_printf(out, "[%d]", (int)(bs->flags & 7));
          break;
      }
      return 1;
  }
  
  /*
   * i2r handler for a sequence of addresses and ranges.
   */
  static int i2r_IPAddressOrRanges(BIO *out,
                                   const int indent,
                                   const IPAddressOrRanges *aors,
                                   const unsigned afi)
  {
      int i;
      for (i = 0; i < sk_IPAddressOrRange_num(aors); i++) {
          const IPAddressOrRange *aor = sk_IPAddressOrRange_value(aors, i);
          BIO_printf(out, "%*s", indent, "");
          switch (aor->type) {
          case IPAddressOrRange_addressPrefix:
              if (!i2r_address(out, afi, 0x00, aor->u.addressPrefix))
                  return 0;
              BIO_printf(out, "/%d\n", addr_prefixlen(aor->u.addressPrefix));
              continue;
          case IPAddressOrRange_addressRange:
              if (!i2r_address(out, afi, 0x00, aor->u.addressRange->min))
                  return 0;
              BIO_puts(out, "-");
              if (!i2r_address(out, afi, 0xFF, aor->u.addressRange->max))
                  return 0;
              BIO_puts(out, "\n");
              continue;
          }
      }
      return 1;
  }
  
  /*
   * i2r handler for an IPAddrBlocks extension.
   */
  static int i2r_IPAddrBlocks(const X509V3_EXT_METHOD *method,
                              void *ext, BIO *out, int indent)
  {
      const IPAddrBlocks *addr = ext;
      int i;
      for (i = 0; i < sk_IPAddressFamily_num(addr); i++) {
          IPAddressFamily *f = sk_IPAddressFamily_value(addr, i);
          const unsigned int afi = X509v3_addr_get_afi(f);
          switch (afi) {
          case IANA_AFI_IPV4:
              BIO_printf(out, "%*sIPv4", indent, "");
              break;
          case IANA_AFI_IPV6:
              BIO_printf(out, "%*sIPv6", indent, "");
              break;
          default:
              BIO_printf(out, "%*sUnknown AFI %u", indent, "", afi);
              break;
          }
          if (f->addressFamily->length > 2) {
              switch (f->addressFamily->data[2]) {
              case 1:
                  BIO_puts(out, " (Unicast)");
                  break;
              case 2:
                  BIO_puts(out, " (Multicast)");
                  break;
              case 3:
                  BIO_puts(out, " (Unicast/Multicast)");
                  break;
              case 4:
                  BIO_puts(out, " (MPLS)");
                  break;
              case 64:
                  BIO_puts(out, " (Tunnel)");
                  break;
              case 65:
                  BIO_puts(out, " (VPLS)");
                  break;
              case 66:
                  BIO_puts(out, " (BGP MDT)");
                  break;
              case 128:
                  BIO_puts(out, " (MPLS-labeled VPN)");
                  break;
              default:
                  BIO_printf(out, " (Unknown SAFI %u)",
                             (unsigned)f->addressFamily->data[2]);
                  break;
              }
          }
          switch (f->ipAddressChoice->type) {
          case IPAddressChoice_inherit:
              BIO_puts(out, ": inherit\n");
              break;
          case IPAddressChoice_addressesOrRanges:
              BIO_puts(out, ":\n");
              if (!i2r_IPAddressOrRanges(out,
                                         indent + 2,
                                         f->ipAddressChoice->
                                         u.addressesOrRanges, afi))
                  return 0;
              break;
          }
      }
      return 1;
  }
  
  /*
   * Sort comparison function for a sequence of IPAddressOrRange
   * elements.
   *
   * There's no sane answer we can give if addr_expand() fails, and an
   * assertion failure on externally supplied data is seriously uncool,
   * so we just arbitrarily declare that if given invalid inputs this
   * function returns -1.  If this messes up your preferred sort order
   * for garbage input, tough noogies.
   */
  static int IPAddressOrRange_cmp(const IPAddressOrRange *a,
                                  const IPAddressOrRange *b, const int length)
  {
      unsigned char addr_a[ADDR_RAW_BUF_LEN], addr_b[ADDR_RAW_BUF_LEN];
      int prefixlen_a = 0, prefixlen_b = 0;
      int r;
  
      switch (a->type) {
      case IPAddressOrRange_addressPrefix:
          if (!addr_expand(addr_a, a->u.addressPrefix, length, 0x00))
              return -1;
          prefixlen_a = addr_prefixlen(a->u.addressPrefix);
          break;
      case IPAddressOrRange_addressRange:
          if (!addr_expand(addr_a, a->u.addressRange->min, length, 0x00))
              return -1;
          prefixlen_a = length * 8;
          break;
      }
  
      switch (b->type) {
      case IPAddressOrRange_addressPrefix:
          if (!addr_expand(addr_b, b->u.addressPrefix, length, 0x00))
              return -1;
          prefixlen_b = addr_prefixlen(b->u.addressPrefix);
          break;
      case IPAddressOrRange_addressRange:
          if (!addr_expand(addr_b, b->u.addressRange->min, length, 0x00))
              return -1;
          prefixlen_b = length * 8;
          break;
      }
  
      if ((r = memcmp(addr_a, addr_b, length)) != 0)
          return r;
      else
          return prefixlen_a - prefixlen_b;
  }
  
  /*
   * IPv4-specific closure over IPAddressOrRange_cmp, since sk_sort()
   * comparison routines are only allowed two arguments.
   */
  static int v4IPAddressOrRange_cmp(const IPAddressOrRange *const *a,
                                    const IPAddressOrRange *const *b)
  {
      return IPAddressOrRange_cmp(*a, *b, 4);
  }
  
  /*
   * IPv6-specific closure over IPAddressOrRange_cmp, since sk_sort()
   * comparison routines are only allowed two arguments.
   */
  static int v6IPAddressOrRange_cmp(const IPAddressOrRange *const *a,
                                    const IPAddressOrRange *const *b)
  {
      return IPAddressOrRange_cmp(*a, *b, 16);
  }
  
  /*
   * Calculate whether a range collapses to a prefix.
   * See last paragraph of RFC 3779 2.2.3.7.
   */
  static int range_should_be_prefix(const unsigned char *min,
                                    const unsigned char *max, const int length)
  {
      unsigned char mask;
      int i, j;
  
      if (memcmp(min, max, length) <= 0)
          return -1;
      for (i = 0; i < length && min[i] == max[i]; i++) ;
      for (j = length - 1; j >= 0 && min[j] == 0x00 && max[j] == 0xFF; j--) ;
      if (i < j)
          return -1;
      if (i > j)
          return i * 8;
      mask = min[i] ^ max[i];
      switch (mask) {
      case 0x01:
          j = 7;
          break;
      case 0x03:
          j = 6;
          break;
      case 0x07:
          j = 5;
          break;
      case 0x0F:
          j = 4;
          break;
      case 0x1F:
          j = 3;
          break;
      case 0x3F:
          j = 2;
          break;
      case 0x7F:
          j = 1;
          break;
      default:
          return -1;
      }
      if ((min[i] & mask) != 0 || (max[i] & mask) != mask)
          return -1;
      else
          return i * 8 + j;
  }
  
  /*
   * Construct a prefix.
   */
  static int make_addressPrefix(IPAddressOrRange **result,
                                unsigned char *addr, const int prefixlen)
  {
      int bytelen = (prefixlen + 7) / 8, bitlen = prefixlen % 8;
      IPAddressOrRange *aor = IPAddressOrRange_new();
  
      if (aor == NULL)
          return 0;
      aor->type = IPAddressOrRange_addressPrefix;
      if (aor->u.addressPrefix == NULL &&
          (aor->u.addressPrefix = ASN1_BIT_STRING_new()) == NULL)
          goto err;
      if (!ASN1_BIT_STRING_set(aor->u.addressPrefix, addr, bytelen))
          goto err;
      aor->u.addressPrefix->flags &= ~7;
      aor->u.addressPrefix->flags |= ASN1_STRING_FLAG_BITS_LEFT;
      if (bitlen > 0) {
          aor->u.addressPrefix->data[bytelen - 1] &= ~(0xFF >> bitlen);
          aor->u.addressPrefix->flags |= 8 - bitlen;
      }
  
      *result = aor;
      return 1;
  
   err:
      IPAddressOrRange_free(aor);
      return 0;
  }
  
  /*
   * Construct a range.  If it can be expressed as a prefix,
   * return a prefix instead.  Doing this here simplifies
   * the rest of the code considerably.
   */
  static int make_addressRange(IPAddressOrRange **result,
                               unsigned char *min,
                               unsigned char *max, const int length)
  {
      IPAddressOrRange *aor;
      int i, prefixlen;
  
      if ((prefixlen = range_should_be_prefix(min, max, length)) >= 0)
          return make_addressPrefix(result, min, prefixlen);
  
      if ((aor = IPAddressOrRange_new()) == NULL)
          return 0;
      aor->type = IPAddressOrRange_addressRange;
      if ((aor->u.addressRange = IPAddressRange_new()) == NULL)
          goto err;
      if (aor->u.addressRange->min == NULL &&
          (aor->u.addressRange->min = ASN1_BIT_STRING_new()) == NULL)
          goto err;
      if (aor->u.addressRange->max == NULL &&
          (aor->u.addressRange->max = ASN1_BIT_STRING_new()) == NULL)
          goto err;
  
      for (i = length; i > 0 && min[i - 1] == 0x00; --i) ;
      if (!ASN1_BIT_STRING_set(aor->u.addressRange->min, min, i))
          goto err;
      aor->u.addressRange->min->flags &= ~7;
      aor->u.addressRange->min->flags |= ASN1_STRING_FLAG_BITS_LEFT;
      if (i > 0) {
          unsigned char b = min[i - 1];
          int j = 1;
          while ((b & (0xFFU >> j)) != 0)
              ++j;
          aor->u.addressRange->min->flags |= 8 - j;
      }
  
      for (i = length; i > 0 && max[i - 1] == 0xFF; --i) ;
      if (!ASN1_BIT_STRING_set(aor->u.addressRange->max, max, i))
          goto err;
      aor->u.addressRange->max->flags &= ~7;
      aor->u.addressRange->max->flags |= ASN1_STRING_FLAG_BITS_LEFT;
      if (i > 0) {
          unsigned char b = max[i - 1];
          int j = 1;
          while ((b & (0xFFU >> j)) != (0xFFU >> j))
              ++j;
          aor->u.addressRange->max->flags |= 8 - j;
      }
  
      *result = aor;
      return 1;
  
   err:
      IPAddressOrRange_free(aor);
      return 0;
  }
  
  /*
   * Construct a new address family or find an existing one.
   */
  static IPAddressFamily *make_IPAddressFamily(IPAddrBlocks *addr,
                                               const unsigned afi,
                                               const unsigned *safi)
  {
      IPAddressFamily *f;
      unsigned char key[3];
      int keylen;
      int i;
  
      key[0] = (afi >> 8) & 0xFF;
      key[1] = afi & 0xFF;
      if (safi != NULL) {
          key[2] = *safi & 0xFF;
          keylen = 3;
      } else {
          keylen = 2;
      }
  
      for (i = 0; i < sk_IPAddressFamily_num(addr); i++) {
          f = sk_IPAddressFamily_value(addr, i);
          if (f->addressFamily->length == keylen &&
              !memcmp(f->addressFamily->data, key, keylen))
              return f;
      }
  
      if ((f = IPAddressFamily_new()) == NULL)
          goto err;
      if (f->ipAddressChoice == NULL &&
          (f->ipAddressChoice = IPAddressChoice_new()) == NULL)
          goto err;
      if (f->addressFamily == NULL &&
          (f->addressFamily = ASN1_OCTET_STRING_new()) == NULL)
          goto err;
      if (!ASN1_OCTET_STRING_set(f->addressFamily, key, keylen))
          goto err;
      if (!sk_IPAddressFamily_push(addr, f))
          goto err;
  
      return f;
  
   err:
      IPAddressFamily_free(f);
      return NULL;
  }
  
  /*
   * Add an inheritance element.
   */
  int X509v3_addr_add_inherit(IPAddrBlocks *addr,
                              const unsigned afi, const unsigned *safi)
  {
      IPAddressFamily *f = make_IPAddressFamily(addr, afi, safi);
      if (f == NULL ||
          f->ipAddressChoice == NULL ||
          (f->ipAddressChoice->type == IPAddressChoice_addressesOrRanges &&
           f->ipAddressChoice->u.addressesOrRanges != NULL))
          return 0;
      if (f->ipAddressChoice->type == IPAddressChoice_inherit &&
          f->ipAddressChoice->u.inherit != NULL)
          return 1;
      if (f->ipAddressChoice->u.inherit == NULL &&
          (f->ipAddressChoice->u.inherit = ASN1_NULL_new()) == NULL)
          return 0;
      f->ipAddressChoice->type = IPAddressChoice_inherit;
      return 1;
  }
  
  /*
   * Construct an IPAddressOrRange sequence, or return an existing one.
   */
  static IPAddressOrRanges *make_prefix_or_range(IPAddrBlocks *addr,
                                                 const unsigned afi,
                                                 const unsigned *safi)
  {
      IPAddressFamily *f = make_IPAddressFamily(addr, afi, safi);
      IPAddressOrRanges *aors = NULL;
  
      if (f == NULL ||
          f->ipAddressChoice == NULL ||
          (f->ipAddressChoice->type == IPAddressChoice_inherit &&
           f->ipAddressChoice->u.inherit != NULL))
          return NULL;
      if (f->ipAddressChoice->type == IPAddressChoice_addressesOrRanges)
          aors = f->ipAddressChoice->u.addressesOrRanges;
      if (aors != NULL)
          return aors;
      if ((aors = sk_IPAddressOrRange_new_null()) == NULL)
          return NULL;
      switch (afi) {
      case IANA_AFI_IPV4:
          (void)sk_IPAddressOrRange_set_cmp_func(aors, v4IPAddressOrRange_cmp);
          break;
      case IANA_AFI_IPV6:
          (void)sk_IPAddressOrRange_set_cmp_func(aors, v6IPAddressOrRange_cmp);
          break;
      }
      f->ipAddressChoice->type = IPAddressChoice_addressesOrRanges;
      f->ipAddressChoice->u.addressesOrRanges = aors;
      return aors;
  }
  
  /*
   * Add a prefix.
   */
  int X509v3_addr_add_prefix(IPAddrBlocks *addr,
                             const unsigned afi,
                             const unsigned *safi,
                             unsigned char *a, const int prefixlen)
  {
      IPAddressOrRanges *aors = make_prefix_or_range(addr, afi, safi);
      IPAddressOrRange *aor;
      if (aors == NULL || !make_addressPrefix(&aor, a, prefixlen))
          return 0;
      if (sk_IPAddressOrRange_push(aors, aor))
          return 1;
      IPAddressOrRange_free(aor);
      return 0;
  }
  
  /*
   * Add a range.
   */
  int X509v3_addr_add_range(IPAddrBlocks *addr,
                            const unsigned afi,
                            const unsigned *safi,
                            unsigned char *min, unsigned char *max)
  {
      IPAddressOrRanges *aors = make_prefix_or_range(addr, afi, safi);
      IPAddressOrRange *aor;
      int length = length_from_afi(afi);
      if (aors == NULL)
          return 0;
      if (!make_addressRange(&aor, min, max, length))
          return 0;
      if (sk_IPAddressOrRange_push(aors, aor))
          return 1;
      IPAddressOrRange_free(aor);
      return 0;
  }
  
  /*
   * Extract min and max values from an IPAddressOrRange.
   */
  static int extract_min_max(IPAddressOrRange *aor,
                             unsigned char *min, unsigned char *max, int length)
  {
      if (aor == NULL || min == NULL || max == NULL)
          return 0;
      switch (aor->type) {
      case IPAddressOrRange_addressPrefix:
          return (addr_expand(min, aor->u.addressPrefix, length, 0x00) &&
                  addr_expand(max, aor->u.addressPrefix, length, 0xFF));
      case IPAddressOrRange_addressRange:
          return (addr_expand(min, aor->u.addressRange->min, length, 0x00) &&
                  addr_expand(max, aor->u.addressRange->max, length, 0xFF));
      }
      return 0;
  }
  
  /*
   * Public wrapper for extract_min_max().
   */
  int X509v3_addr_get_range(IPAddressOrRange *aor,
                            const unsigned afi,
                            unsigned char *min,
                            unsigned char *max, const int length)
  {
      int afi_length = length_from_afi(afi);
      if (aor == NULL || min == NULL || max == NULL ||
          afi_length == 0 || length < afi_length ||
          (aor->type != IPAddressOrRange_addressPrefix &&
           aor->type != IPAddressOrRange_addressRange) ||
          !extract_min_max(aor, min, max, afi_length))
          return 0;
  
      return afi_length;
  }
  
  /*
   * Sort comparison function for a sequence of IPAddressFamily.
   *
   * The last paragraph of RFC 3779 2.2.3.3 is slightly ambiguous about
   * the ordering: I can read it as meaning that IPv6 without a SAFI
   * comes before IPv4 with a SAFI, which seems pretty weird.  The
   * examples in appendix B suggest that the author intended the
   * null-SAFI rule to apply only within a single AFI, which is what I
   * would have expected and is what the following code implements.
   */
  static int IPAddressFamily_cmp(const IPAddressFamily *const *a_,
                                 const IPAddressFamily *const *b_)
  {
      const ASN1_OCTET_STRING *a = (*a_)->addressFamily;
      const ASN1_OCTET_STRING *b = (*b_)->addressFamily;
      int len = ((a->length <= b->length) ? a->length : b->length);
      int cmp = memcmp(a->data, b->data, len);
      return cmp ? cmp : a->length - b->length;
  }
  
  /*
   * Check whether an IPAddrBLocks is in canonical form.
   */
  int X509v3_addr_is_canonical(IPAddrBlocks *addr)
  {
      unsigned char a_min[ADDR_RAW_BUF_LEN], a_max[ADDR_RAW_BUF_LEN];
      unsigned char b_min[ADDR_RAW_BUF_LEN], b_max[ADDR_RAW_BUF_LEN];
      IPAddressOrRanges *aors;
      int i, j, k;
  
      /*
       * Empty extension is canonical.
       */
      if (addr == NULL)
          return 1;
  
      /*
       * Check whether the top-level list is in order.
       */
      for (i = 0; i < sk_IPAddressFamily_num(addr) - 1; i++) {
          const IPAddressFamily *a = sk_IPAddressFamily_value(addr, i);
          const IPAddressFamily *b = sk_IPAddressFamily_value(addr, i + 1);
          if (IPAddressFamily_cmp(&a, &b) >= 0)
              return 0;
      }
  
      /*
       * Top level's ok, now check each address family.
       */
      for (i = 0; i < sk_IPAddressFamily_num(addr); i++) {
          IPAddressFamily *f = sk_IPAddressFamily_value(addr, i);
          int length = length_from_afi(X509v3_addr_get_afi(f));
  
          /*
           * Inheritance is canonical.  Anything other than inheritance or
           * a SEQUENCE OF IPAddressOrRange is an ASN.1 error or something.
           */
          if (f == NULL || f->ipAddressChoice == NULL)
              return 0;
          switch (f->ipAddressChoice->type) {
          case IPAddressChoice_inherit:
              continue;
          case IPAddressChoice_addressesOrRanges:
              break;
          default:
              return 0;
          }
  
          /*
           * It's an IPAddressOrRanges sequence, check it.
           */
          aors = f->ipAddressChoice->u.addressesOrRanges;
          if (sk_IPAddressOrRange_num(aors) == 0)
              return 0;
          for (j = 0; j < sk_IPAddressOrRange_num(aors) - 1; j++) {
              IPAddressOrRange *a = sk_IPAddressOrRange_value(aors, j);
              IPAddressOrRange *b = sk_IPAddressOrRange_value(aors, j + 1);
  
              if (!extract_min_max(a, a_min, a_max, length) ||
                  !extract_min_max(b, b_min, b_max, length))
                  return 0;
  
              /*
               * Punt misordered list, overlapping start, or inverted range.
               */
              if (memcmp(a_min, b_min, length) >= 0 ||
                  memcmp(a_min, a_max, length) > 0 ||
                  memcmp(b_min, b_max, length) > 0)
                  return 0;
  
              /*
               * Punt if adjacent or overlapping.  Check for adjacency by
               * subtracting one from b_min first.
               */
              for (k = length - 1; k >= 0 && b_min[k]-- == 0x00; k--) ;
              if (memcmp(a_max, b_min, length) >= 0)
                  return 0;
  
              /*
               * Check for range that should be expressed as a prefix.
               */
              if (a->type == IPAddressOrRange_addressRange &&
                  range_should_be_prefix(a_min, a_max, length) >= 0)
                  return 0;
          }
  
          /*
           * Check range to see if it's inverted or should be a
           * prefix.
           */
          j = sk_IPAddressOrRange_num(aors) - 1;
          {
              IPAddressOrRange *a = sk_IPAddressOrRange_value(aors, j);
              if (a != NULL && a->type == IPAddressOrRange_addressRange) {
                  if (!extract_min_max(a, a_min, a_max, length))
                      return 0;
                  if (memcmp(a_min, a_max, length) > 0 ||
                      range_should_be_prefix(a_min, a_max, length) >= 0)
                      return 0;
              }
          }
      }
  
      /*
       * If we made it through all that, we're happy.
       */
      return 1;
  }
  
  /*
   * Whack an IPAddressOrRanges into canonical form.
   */
  static int IPAddressOrRanges_canonize(IPAddressOrRanges *aors,
                                        const unsigned afi)
  {
      int i, j, length = length_from_afi(afi);
  
      /*
       * Sort the IPAddressOrRanges sequence.
       */
      sk_IPAddressOrRange_sort(aors);
  
      /*
       * Clean up representation issues, punt on duplicates or overlaps.
       */
      for (i = 0; i < sk_IPAddressOrRange_num(aors) - 1; i++) {
          IPAddressOrRange *a = sk_IPAddressOrRange_value(aors, i);
          IPAddressOrRange *b = sk_IPAddressOrRange_value(aors, i + 1);
          unsigned char a_min[ADDR_RAW_BUF_LEN], a_max[ADDR_RAW_BUF_LEN];
          unsigned char b_min[ADDR_RAW_BUF_LEN], b_max[ADDR_RAW_BUF_LEN];
  
          if (!extract_min_max(a, a_min, a_max, length) ||
              !extract_min_max(b, b_min, b_max, length))
              return 0;
  
          /*
           * Punt inverted ranges.
           */
          if (memcmp(a_min, a_max, length) > 0 ||
              memcmp(b_min, b_max, length) > 0)
              return 0;
  
          /*
           * Punt overlaps.
           */
          if (memcmp(a_max, b_min, length) >= 0)
              return 0;
  
          /*
           * Merge if a and b are adjacent.  We check for
           * adjacency by subtracting one from b_min first.
           */
          for (j = length - 1; j >= 0 && b_min[j]-- == 0x00; j--) ;
          if (memcmp(a_max, b_min, length) == 0) {
              IPAddressOrRange *merged;
              if (!make_addressRange(&merged, a_min, b_max, length))
                  return 0;
              (void)sk_IPAddressOrRange_set(aors, i, merged);
              (void)sk_IPAddressOrRange_delete(aors, i + 1);
              IPAddressOrRange_free(a);
              IPAddressOrRange_free(b);
              --i;
              continue;
          }
      }
  
      /*
       * Check for inverted final range.
       */
      j = sk_IPAddressOrRange_num(aors) - 1;
      {
          IPAddressOrRange *a = sk_IPAddressOrRange_value(aors, j);
          if (a != NULL && a->type == IPAddressOrRange_addressRange) {
              unsigned char a_min[ADDR_RAW_BUF_LEN], a_max[ADDR_RAW_BUF_LEN];
              if (!extract_min_max(a, a_min, a_max, length))
                  return 0;
              if (memcmp(a_min, a_max, length) > 0)
                  return 0;
          }
      }
  
      return 1;
  }
  
  /*
   * Whack an IPAddrBlocks extension into canonical form.
   */
  int X509v3_addr_canonize(IPAddrBlocks *addr)
  {
      int i;
      for (i = 0; i < sk_IPAddressFamily_num(addr); i++) {
          IPAddressFamily *f = sk_IPAddressFamily_value(addr, i);
          if (f->ipAddressChoice->type == IPAddressChoice_addressesOrRanges &&
              !IPAddressOrRanges_canonize(f->ipAddressChoice->
                                          u.addressesOrRanges,
                                          X509v3_addr_get_afi(f)))
              return 0;
      }
      (void)sk_IPAddressFamily_set_cmp_func(addr, IPAddressFamily_cmp);
      sk_IPAddressFamily_sort(addr);
      if (!ossl_assert(X509v3_addr_is_canonical(addr)))
          return 0;
      return 1;
  }
  
  /*
   * v2i handler for the IPAddrBlocks extension.
   */
  static void *v2i_IPAddrBlocks(const struct v3_ext_method *method,
                                struct v3_ext_ctx *ctx,
                                STACK_OF(CONF_VALUE) *values)
  {
      static const char v4addr_chars[] = "0123456789.";
      static const char v6addr_chars[] = "0123456789.:abcdefABCDEF";
      IPAddrBlocks *addr = NULL;
      char *s = NULL, *t;
      int i;
  
      if ((addr = sk_IPAddressFamily_new(IPAddressFamily_cmp)) == NULL) {
          ERR_raise(ERR_LIB_X509V3, ERR_R_MALLOC_FAILURE);
          return NULL;
      }
  
      for (i = 0; i < sk_CONF_VALUE_num(values); i++) {
          CONF_VALUE *val = sk_CONF_VALUE_value(values, i);
          unsigned char min[ADDR_RAW_BUF_LEN], max[ADDR_RAW_BUF_LEN];
          unsigned afi, *safi = NULL, safi_;
          const char *addr_chars = NULL;
          int prefixlen, i1, i2, delim, length;
  
          if (!v3_name_cmp(val->name, "IPv4")) {
              afi = IANA_AFI_IPV4;
          } else if (!v3_name_cmp(val->name, "IPv6")) {
              afi = IANA_AFI_IPV6;
          } else if (!v3_name_cmp(val->name, "IPv4-SAFI")) {
              afi = IANA_AFI_IPV4;
              safi = &safi_;
          } else if (!v3_name_cmp(val->name, "IPv6-SAFI")) {
              afi = IANA_AFI_IPV6;
              safi = &safi_;
          } else {
              ERR_raise_data(ERR_LIB_X509V3, X509V3_R_EXTENSION_NAME_ERROR,
                             "%s", val->name);
              goto err;
          }
  
          switch (afi) {
          case IANA_AFI_IPV4:
              addr_chars = v4addr_chars;
              break;
          case IANA_AFI_IPV6:
              addr_chars = v6addr_chars;
              break;
          }
  
          length = length_from_afi(afi);
  
          /*
           * Handle SAFI, if any, and OPENSSL_strdup() so we can null-terminate
           * the other input values.
           */
          if (safi != NULL) {
              *safi = strtoul(val->value, &t, 0);
              t += strspn(t, " \t");
              if (*safi > 0xFF || *t++ != ':') {
                  ERR_raise(ERR_LIB_X509V3, X509V3_R_INVALID_SAFI);
                  X509V3_conf_add_error_name_value(val);
                  goto err;
              }
              t += strspn(t, " \t");
              s = OPENSSL_strdup(t);
          } else {
              s = OPENSSL_strdup(val->value);
          }
          if (s == NULL) {
              ERR_raise(ERR_LIB_X509V3, ERR_R_MALLOC_FAILURE);
              goto err;
          }
  
          /*
           * Check for inheritance.  Not worth additional complexity to
           * optimize this (seldom-used) case.
           */
          if (strcmp(s, "inherit") == 0) {
              if (!X509v3_addr_add_inherit(addr, afi, safi)) {
                  ERR_raise(ERR_LIB_X509V3, X509V3_R_INVALID_INHERITANCE);
                  X509V3_conf_add_error_name_value(val);
                  goto err;
              }
              OPENSSL_free(s);
              s = NULL;
              continue;
          }
  
          i1 = strspn(s, addr_chars);
          i2 = i1 + strspn(s + i1, " \t");
          delim = s[i2++];
          s[i1] = '\0';
  
          if (a2i_ipadd(min, s) != length) {
              ERR_raise(ERR_LIB_X509V3, X509V3_R_INVALID_IPADDRESS);
              X509V3_conf_add_error_name_value(val);
              goto err;
          }
  
          switch (delim) {
          case '/':
              prefixlen = (int)strtoul(s + i2, &t, 10);
              if (t == s + i2 || *t != '\0') {
                  ERR_raise(ERR_LIB_X509V3, X509V3_R_EXTENSION_VALUE_ERROR);
                  X509V3_conf_add_error_name_value(val);
                  goto err;
              }
              if (!X509v3_addr_add_prefix(addr, afi, safi, min, prefixlen)) {
                  ERR_raise(ERR_LIB_X509V3, ERR_R_MALLOC_FAILURE);
                  goto err;
              }
              break;
          case '-':
              i1 = i2 + strspn(s + i2, " \t");
              i2 = i1 + strspn(s + i1, addr_chars);
              if (i1 == i2 || s[i2] != '\0') {
                  ERR_raise(ERR_LIB_X509V3, X509V3_R_EXTENSION_VALUE_ERROR);
                  X509V3_conf_add_error_name_value(val);
                  goto err;
              }
              if (a2i_ipadd(max, s + i1) != length) {
                  ERR_raise(ERR_LIB_X509V3, X509V3_R_INVALID_IPADDRESS);
                  X509V3_conf_add_error_name_value(val);
                  goto err;
              }
              if (memcmp(min, max, length_from_afi(afi)) > 0) {
                  ERR_raise(ERR_LIB_X509V3, X509V3_R_EXTENSION_VALUE_ERROR);
                  X509V3_conf_add_error_name_value(val);
                  goto err;
              }
              if (!X509v3_addr_add_range(addr, afi, safi, min, max)) {
                  ERR_raise(ERR_LIB_X509V3, ERR_R_MALLOC_FAILURE);
                  goto err;
              }
              break;
          case '\0':
              if (!X509v3_addr_add_prefix(addr, afi, safi, min, length * 8)) {
                  ERR_raise(ERR_LIB_X509V3, ERR_R_MALLOC_FAILURE);
                  goto err;
              }
              break;
          default:
              ERR_raise(ERR_LIB_X509V3, X509V3_R_EXTENSION_VALUE_ERROR);
              X509V3_conf_add_error_name_value(val);
              goto err;
          }
  
          OPENSSL_free(s);
          s = NULL;
      }
  
      /*
       * Canonize the result, then we're done.
       */
      if (!X509v3_addr_canonize(addr))
          goto err;
      return addr;
  
   err:
      OPENSSL_free(s);
      sk_IPAddressFamily_pop_free(addr, IPAddressFamily_free);
      return NULL;
  }
  
  /*
   * OpenSSL dispatch
   */
  const X509V3_EXT_METHOD v3_addr = {
      NID_sbgp_ipAddrBlock,       /* nid */
      0,                          /* flags */
      ASN1_ITEM_ref(IPAddrBlocks), /* template */
      0, 0, 0, 0,                 /* old functions, ignored */
      0,                          /* i2s */
      0,                          /* s2i */
      0,                          /* i2v */
      v2i_IPAddrBlocks,           /* v2i */
      i2r_IPAddrBlocks,           /* i2r */
      0,                          /* r2i */
      NULL                        /* extension-specific data */
  };
  
  /*
   * Figure out whether extension sues inheritance.
   */
  int X509v3_addr_inherits(IPAddrBlocks *addr)
  {
      int i;
      if (addr == NULL)
          return 0;
      for (i = 0; i < sk_IPAddressFamily_num(addr); i++) {
          IPAddressFamily *f = sk_IPAddressFamily_value(addr, i);
          if (f->ipAddressChoice->type == IPAddressChoice_inherit)
              return 1;
      }
      return 0;
  }
  
  /*
   * Figure out whether parent contains child.
   */
  static int addr_contains(IPAddressOrRanges *parent,
                           IPAddressOrRanges *child, int length)
  {
      unsigned char p_min[ADDR_RAW_BUF_LEN], p_max[ADDR_RAW_BUF_LEN];
      unsigned char c_min[ADDR_RAW_BUF_LEN], c_max[ADDR_RAW_BUF_LEN];
      int p, c;
  
      if (child == NULL || parent == child)
          return 1;
      if (parent == NULL)
          return 0;
  
      p = 0;
      for (c = 0; c < sk_IPAddressOrRange_num(child); c++) {
          if (!extract_min_max(sk_IPAddressOrRange_value(child, c),
                               c_min, c_max, length))
              return -1;
          for (;; p++) {
              if (p >= sk_IPAddressOrRange_num(parent))
                  return 0;
              if (!extract_min_max(sk_IPAddressOrRange_value(parent, p),
                                   p_min, p_max, length))
                  return 0;
              if (memcmp(p_max, c_max, length) < 0)
                  continue;
              if (memcmp(p_min, c_min, length) > 0)
                  return 0;
              break;
          }
      }
  
      return 1;
  }
  
  /*
   * Test whether a is a subset of b.
   */
  int X509v3_addr_subset(IPAddrBlocks *a, IPAddrBlocks *b)
  {
      int i;
      if (a == NULL || a == b)
          return 1;
      if (b == NULL || X509v3_addr_inherits(a) || X509v3_addr_inherits(b))
          return 0;
      (void)sk_IPAddressFamily_set_cmp_func(b, IPAddressFamily_cmp);
      for (i = 0; i < sk_IPAddressFamily_num(a); i++) {
          IPAddressFamily *fa = sk_IPAddressFamily_value(a, i);
          int j = sk_IPAddressFamily_find(b, fa);
          IPAddressFamily *fb;
          fb = sk_IPAddressFamily_value(b, j);
          if (fb == NULL)
              return 0;
          if (!addr_contains(fb->ipAddressChoice->u.addressesOrRanges,
                             fa->ipAddressChoice->u.addressesOrRanges,
                             length_from_afi(X509v3_addr_get_afi(fb))))
              return 0;
      }
      return 1;
  }
  
  /*
   * Validation error handling via callback.
   */
  #define validation_err(_err_)           \
    do {                                  \
      if (ctx != NULL) {                  \
        ctx->error = _err_;               \
        ctx->error_depth = i;             \
        ctx->current_cert = x;            \
        ret = ctx->verify_cb(0, ctx);     \
      } else {                            \
        ret = 0;                          \
      }                                   \
      if (!ret)                           \
        goto done;                        \
    } while (0)
  
  /*
   * Core code for RFC 3779 2.3 path validation.
   *
   * Returns 1 for success, 0 on error.
   *
   * When returning 0, ctx->error MUST be set to an appropriate value other than
   * X509_V_OK.
   */
  static int addr_validate_path_internal(X509_STORE_CTX *ctx,
                                         STACK_OF(X509) *chain,
                                         IPAddrBlocks *ext)
  {
      IPAddrBlocks *child = NULL;
      int i, j, ret = 1;
      X509 *x;
  
      if (!ossl_assert(chain != NULL && sk_X509_num(chain) > 0)
              || !ossl_assert(ctx != NULL || ext != NULL)
              || !ossl_assert(ctx == NULL || ctx->verify_cb != NULL)) {
          if (ctx != NULL)
              ctx->error = X509_V_ERR_UNSPECIFIED;
          return 0;
      }
  
      /*
       * Figure out where to start.  If we don't have an extension to
       * check, we're done.  Otherwise, check canonical form and
       * set up for walking up the chain.
       */
      if (ext != NULL) {
          i = -1;
          x = NULL;
      } else {
          i = 0;
          x = sk_X509_value(chain, i);
          if ((ext = x->rfc3779_addr) == NULL)
              goto done;
      }
      if (!X509v3_addr_is_canonical(ext))
          validation_err(X509_V_ERR_INVALID_EXTENSION);
      (void)sk_IPAddressFamily_set_cmp_func(ext, IPAddressFamily_cmp);
      if ((child = sk_IPAddressFamily_dup(ext)) == NULL) {
          ERR_raise(ERR_LIB_X509V3, ERR_R_MALLOC_FAILURE);
          if (ctx != NULL)
              ctx->error = X509_V_ERR_OUT_OF_MEM;
          ret = 0;
          goto done;
      }
  
      /*
       * Now walk up the chain.  No cert may list resources that its
       * parent doesn't list.
       */
      for (i++; i < sk_X509_num(chain); i++) {
          x = sk_X509_value(chain, i);
          if (!X509v3_addr_is_canonical(x->rfc3779_addr))
              validation_err(X509_V_ERR_INVALID_EXTENSION);
          if (x->rfc3779_addr == NULL) {
              for (j = 0; j < sk_IPAddressFamily_num(child); j++) {
                  IPAddressFamily *fc = sk_IPAddressFamily_value(child, j);
                  if (fc->ipAddressChoice->type != IPAddressChoice_inherit) {
                      validation_err(X509_V_ERR_UNNESTED_RESOURCE);
                      break;
                  }
              }
              continue;
          }
          (void)sk_IPAddressFamily_set_cmp_func(x->rfc3779_addr,
                                                IPAddressFamily_cmp);
          for (j = 0; j < sk_IPAddressFamily_num(child); j++) {
              IPAddressFamily *fc = sk_IPAddressFamily_value(child, j);
              int k = sk_IPAddressFamily_find(x->rfc3779_addr, fc);
              IPAddressFamily *fp =
                  sk_IPAddressFamily_value(x->rfc3779_addr, k);
              if (fp == NULL) {
                  if (fc->ipAddressChoice->type ==
                      IPAddressChoice_addressesOrRanges) {
                      validation_err(X509_V_ERR_UNNESTED_RESOURCE);
                      break;
                  }
                  continue;
              }
              if (fp->ipAddressChoice->type ==
                  IPAddressChoice_addressesOrRanges) {
                  if (fc->ipAddressChoice->type == IPAddressChoice_inherit
                      || addr_contains(fp->ipAddressChoice->u.addressesOrRanges,
                                       fc->ipAddressChoice->u.addressesOrRanges,
                                       length_from_afi(X509v3_addr_get_afi(fc))))
                      (void)sk_IPAddressFamily_set(child, j, fp);
                  else
                      validation_err(X509_V_ERR_UNNESTED_RESOURCE);
              }
          }
      }
  
      /*
       * Trust anchor can't inherit.
       */
      if (x->rfc3779_addr != NULL) {
          for (j = 0; j < sk_IPAddressFamily_num(x->rfc3779_addr); j++) {
              IPAddressFamily *fp =
                  sk_IPAddressFamily_value(x->rfc3779_addr, j);
              if (fp->ipAddressChoice->type == IPAddressChoice_inherit
                  && sk_IPAddressFamily_find(child, fp) >= 0)
                  validation_err(X509_V_ERR_UNNESTED_RESOURCE);
          }
      }
  
   done:
      sk_IPAddressFamily_free(child);
      return ret;
  }
  
  #undef validation_err
  
  /*
   * RFC 3779 2.3 path validation -- called from X509_verify_cert().
   */
  int X509v3_addr_validate_path(X509_STORE_CTX *ctx)
  {
      if (ctx->chain == NULL
              || sk_X509_num(ctx->chain) == 0
              || ctx->verify_cb == NULL) {
          ctx->error = X509_V_ERR_UNSPECIFIED;
          return 0;
      }
      return addr_validate_path_internal(ctx, ctx->chain, NULL);
  }
  
  /*
   * RFC 3779 2.3 path validation of an extension.
   * Test whether chain covers extension.
   */
  int X509v3_addr_validate_resource_set(STACK_OF(X509) *chain,
                                    IPAddrBlocks *ext, int allow_inheritance)
  {
      if (ext == NULL)
          return 1;
      if (chain == NULL || sk_X509_num(chain) == 0)
          return 0;
      if (!allow_inheritance && X509v3_addr_inherits(ext))
          return 0;
      return addr_validate_path_internal(NULL, chain, ext);
  }
  
  #endif                          /* OPENSSL_NO_RFC3779 */
  