/src/libressl/crypto/x509/x509_addr.c

Source (jump to first uncovered line)
/*  $OpenBSD: x509_addr.c,v 1.83 2022/05/25 17:10:30 tb Exp $ */
/*
 * Contributed to the OpenSSL Project by the American Registry for
 * Internet Numbers ("ARIN").
 */
/* ====================================================================
 * Copyright (c) 2006-2016 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).
 */

/*
 * Implementation of RFC 3779 section 2.2.
 */

#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <openssl/asn1.h>
#include <openssl/asn1t.h>
#include <openssl/buffer.h>
#include <openssl/conf.h>
#include <openssl/err.h>
#include <openssl/x509.h>
#include <openssl/x509v3.h>

#include "asn1_locl.h"
#include "bytestring.h"
#include "x509_lcl.h"

#ifndef OPENSSL_NO_RFC3779

/*
 * OpenSSL ASN.1 template translation of RFC 3779 2.2.3.
 */

static const ASN1_TEMPLATE IPAddressRange_seq_tt[] = {
  {
    .flags = 0,
    .tag = 0,
    .offset = offsetof(IPAddressRange, min),
    .field_name = "min",
    .item = &ASN1_BIT_STRING_it,
  },
  {
    .flags = 0,
    .tag = 0,
    .offset = offsetof(IPAddressRange, max),
    .field_name = "max",
    .item = &ASN1_BIT_STRING_it,
  },
};

const ASN1_ITEM IPAddressRange_it = {
  .itype = ASN1_ITYPE_SEQUENCE,
  .utype = V_ASN1_SEQUENCE,
  .templates = IPAddressRange_seq_tt,
  .tcount = sizeof(IPAddressRange_seq_tt) / sizeof(ASN1_TEMPLATE),
  .funcs = NULL,
  .size = sizeof(IPAddressRange),
  .sname = "IPAddressRange",
};

static const ASN1_TEMPLATE IPAddressOrRange_ch_tt[] = {
  {
    .flags = 0,
    .tag = 0,
    .offset = offsetof(IPAddressOrRange, u.addressPrefix),
    .field_name = "u.addressPrefix",
    .item = &ASN1_BIT_STRING_it,
  },
  {
    .flags = 0,
    .tag = 0,
    .offset = offsetof(IPAddressOrRange, u.addressRange),
    .field_name = "u.addressRange",
    .item = &IPAddressRange_it,
  },
};

const ASN1_ITEM IPAddressOrRange_it = {
  .itype = ASN1_ITYPE_CHOICE,
  .utype = offsetof(IPAddressOrRange, type),
  .templates = IPAddressOrRange_ch_tt,
  .tcount = sizeof(IPAddressOrRange_ch_tt) / sizeof(ASN1_TEMPLATE),
  .funcs = NULL,
  .size = sizeof(IPAddressOrRange),
  .sname = "IPAddressOrRange",
};

static const ASN1_TEMPLATE IPAddressChoice_ch_tt[] = {
  {
    .flags = 0,
    .tag = 0,
    .offset = offsetof(IPAddressChoice, u.inherit),
    .field_name = "u.inherit",
    .item = &ASN1_NULL_it,
  },
  {
    .flags = ASN1_TFLG_SEQUENCE_OF,
    .tag = 0,
    .offset = offsetof(IPAddressChoice, u.addressesOrRanges),
    .field_name = "u.addressesOrRanges",
    .item = &IPAddressOrRange_it,
  },
};

const ASN1_ITEM IPAddressChoice_it = {
  .itype = ASN1_ITYPE_CHOICE,
  .utype = offsetof(IPAddressChoice, type),
  .templates = IPAddressChoice_ch_tt,
  .tcount = sizeof(IPAddressChoice_ch_tt) / sizeof(ASN1_TEMPLATE),
  .funcs = NULL,
  .size = sizeof(IPAddressChoice),
  .sname = "IPAddressChoice",
};

static const ASN1_TEMPLATE IPAddressFamily_seq_tt[] = {
  {
    .flags = 0,
    .tag = 0,
    .offset = offsetof(IPAddressFamily, addressFamily),
    .field_name = "addressFamily",
    .item = &ASN1_OCTET_STRING_it,
  },
  {
    .flags = 0,
    .tag = 0,
    .offset = offsetof(IPAddressFamily, ipAddressChoice),
    .field_name = "ipAddressChoice",
    .item = &IPAddressChoice_it,
  },
};

const ASN1_ITEM IPAddressFamily_it = {
  .itype = ASN1_ITYPE_SEQUENCE,
  .utype = V_ASN1_SEQUENCE,
  .templates = IPAddressFamily_seq_tt,
  .tcount = sizeof(IPAddressFamily_seq_tt) / sizeof(ASN1_TEMPLATE),
  .funcs = NULL,
  .size = sizeof(IPAddressFamily),
  .sname = "IPAddressFamily",
};

static const ASN1_TEMPLATE IPAddrBlocks_item_tt = {
  .flags = ASN1_TFLG_SEQUENCE_OF,
  .tag = 0,
  .offset = 0,
  .field_name = "IPAddrBlocks",
  .item = &IPAddressFamily_it,
};

static const ASN1_ITEM IPAddrBlocks_it = {
  .itype = ASN1_ITYPE_PRIMITIVE,
  .utype = -1,
  .templates = &IPAddrBlocks_item_tt,
  .tcount = 0,
  .funcs = NULL,
  .size = 0,
  .sname = "IPAddrBlocks",
};

IPAddressRange *
d2i_IPAddressRange(IPAddressRange **a, const unsigned char **in, long len)
{
  return (IPAddressRange *)ASN1_item_d2i((ASN1_VALUE **)a, in, len,
      &IPAddressRange_it);
}

int
i2d_IPAddressRange(IPAddressRange *a, unsigned char **out)
{
  return ASN1_item_i2d((ASN1_VALUE *)a, out, &IPAddressRange_it);
}

IPAddressRange *
IPAddressRange_new(void)
{
  return (IPAddressRange *)ASN1_item_new(&IPAddressRange_it);
}

void
IPAddressRange_free(IPAddressRange *a)
{
  ASN1_item_free((ASN1_VALUE *)a, &IPAddressRange_it);
}

IPAddressOrRange *
d2i_IPAddressOrRange(IPAddressOrRange **a, const unsigned char **in, long len)
{
  return (IPAddressOrRange *)ASN1_item_d2i((ASN1_VALUE **)a, in, len,
      &IPAddressOrRange_it);
}

int
i2d_IPAddressOrRange(IPAddressOrRange *a, unsigned char **out)
{
  return ASN1_item_i2d((ASN1_VALUE *)a, out, &IPAddressOrRange_it);
}

IPAddressOrRange *
IPAddressOrRange_new(void)
{
  return (IPAddressOrRange *)ASN1_item_new(&IPAddressOrRange_it);
}

void
IPAddressOrRange_free(IPAddressOrRange *a)
{
  ASN1_item_free((ASN1_VALUE *)a, &IPAddressOrRange_it);
}

IPAddressChoice *
d2i_IPAddressChoice(IPAddressChoice **a, const unsigned char **in, long len)
{
  return (IPAddressChoice *)ASN1_item_d2i((ASN1_VALUE **)a, in, len,
      &IPAddressChoice_it);
}

int
i2d_IPAddressChoice(IPAddressChoice *a, unsigned char **out)
{
  return ASN1_item_i2d((ASN1_VALUE *)a, out, &IPAddressChoice_it);
}

IPAddressChoice *
IPAddressChoice_new(void)
{
  return (IPAddressChoice *)ASN1_item_new(&IPAddressChoice_it);
}

void
IPAddressChoice_free(IPAddressChoice *a)
{
  ASN1_item_free((ASN1_VALUE *)a, &IPAddressChoice_it);
}

IPAddressFamily *
d2i_IPAddressFamily(IPAddressFamily **a, const unsigned char **in, long len)
{
  return (IPAddressFamily *)ASN1_item_d2i((ASN1_VALUE **)a, in, len,
      &IPAddressFamily_it);
}

int
i2d_IPAddressFamily(IPAddressFamily *a, unsigned char **out)
{
  return ASN1_item_i2d((ASN1_VALUE *)a, out, &IPAddressFamily_it);
}

IPAddressFamily *
IPAddressFamily_new(void)
{
  return (IPAddressFamily *)ASN1_item_new(&IPAddressFamily_it);
}

void
IPAddressFamily_free(IPAddressFamily *a)
{
  ASN1_item_free((ASN1_VALUE *)a, &IPAddressFamily_it);
}

/*
 * Convenience accessors for IPAddressFamily.
 */

static int
IPAddressFamily_type(IPAddressFamily *af)
{
  /* XXX - can af->ipAddressChoice == NULL actually happen? */
  if (af == NULL || af->ipAddressChoice == NULL)
    return -1;

  switch (af->ipAddressChoice->type) {
  case IPAddressChoice_inherit:
  case IPAddressChoice_addressesOrRanges:
    return af->ipAddressChoice->type;
  default:
    return -1;
  }
}

static IPAddressOrRanges *
IPAddressFamily_addressesOrRanges(IPAddressFamily *af)
{
  if (IPAddressFamily_type(af) == IPAddressChoice_addressesOrRanges)
    return af->ipAddressChoice->u.addressesOrRanges;

  return NULL;
}

static ASN1_NULL *
IPAddressFamily_inheritance(IPAddressFamily *af)
{
  if (IPAddressFamily_type(af) == IPAddressChoice_inherit)
    return af->ipAddressChoice->u.inherit;

  return NULL;
}

static int
IPAddressFamily_set_inheritance(IPAddressFamily *af)
{
  if (IPAddressFamily_addressesOrRanges(af) != NULL)
    return 0;

  if (IPAddressFamily_inheritance(af) != NULL)
    return 1;

  if ((af->ipAddressChoice->u.inherit = ASN1_NULL_new()) == NULL)
    return 0;
  af->ipAddressChoice->type = IPAddressChoice_inherit;

  return 1;
}

/*
 * 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;
  }
}

/*
 * Get AFI and optional SAFI from an IPAddressFamily. All three out arguments
 * are optional; if |out_safi| is non-NULL, |safi_is_set| must be non-NULL.
 */
static int
IPAddressFamily_afi_safi(const IPAddressFamily *af, uint16_t *out_afi,
    uint8_t *out_safi, int *safi_is_set)
{
  CBS cbs;
  uint16_t afi;
  uint8_t safi = 0;
  int got_safi = 0;

  CBS_init(&cbs, af->addressFamily->data, af->addressFamily->length);

  if (!CBS_get_u16(&cbs, &afi))
    return 0;

  /* Fetch the optional SAFI. */
  if (CBS_len(&cbs) != 0) {
    if (!CBS_get_u8(&cbs, &safi))
      return 0;
    got_safi = 1;
  }

  /* If there's anything left, it's garbage. */
  if (CBS_len(&cbs) != 0)
    return 0;

  /* XXX - error on reserved AFI/SAFI? */

  if (out_afi != NULL)
    *out_afi = afi;

  if (out_safi != NULL) {
    *out_safi = safi;
    *safi_is_set = got_safi;
  }

  return 1;
}

static int
IPAddressFamily_afi(const IPAddressFamily *af, uint16_t *out_afi)
{
  return IPAddressFamily_afi_safi(af, out_afi, NULL, NULL);
}

static int
IPAddressFamily_afi_is_valid(const IPAddressFamily *af)
{
  return IPAddressFamily_afi_safi(af, NULL, NULL, NULL);
}

static int
IPAddressFamily_afi_length(const IPAddressFamily *af, int *out_length)
{
  uint16_t afi;

  *out_length = 0;

  if (!IPAddressFamily_afi(af, &afi))
    return 0;

  *out_length = length_from_afi(afi);

  return 1;
}

#define MINIMUM(a, b) (((a) < (b)) ? (a) : (b))

/*
 * 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, cmp;

  len = MINIMUM(a->length, b->length);

  if ((cmp = memcmp(a->data, b->data, len)) != 0)
    return cmp;

  return a->length - b->length;
}

static IPAddressFamily *
IPAddressFamily_find_in_parent(IPAddrBlocks *parent, IPAddressFamily *child_af)
{
  int index;

  (void)sk_IPAddressFamily_set_cmp_func(parent, IPAddressFamily_cmp);

  if ((index = sk_IPAddressFamily_find(parent, child_af)) < 0)
    return NULL;

  return sk_IPAddressFamily_value(parent, index);
}

/*
 * Extract the AFI from an IPAddressFamily.
 *
 * This is public API. It uses the reserved AFI 0 as an in-band error
 * while it doesn't care about the reserved AFI 65535...
 */
unsigned int
X509v3_addr_get_afi(const IPAddressFamily *af)
{
  uint16_t afi;

  /*
   * XXX are these NULL checks really sensible? If af is non-NULL, it
   * should have both addressFamily and ipAddressChoice...
   */
  if (af == NULL || af->addressFamily == NULL ||
      af->addressFamily->data == NULL)
    return 0;

  if (!IPAddressFamily_afi(af, &afi))
    return 0;

  return afi;
}

/*
 * Expand the bitstring form (RFC 3779, section 2.1.2) of an address into
 * a raw byte array.  At the moment this is coded for simplicity, not speed.
 *
 * Unused bits in the last octet of |bs| and all bits in subsequent bytes
 * of |addr| are set to 0 or 1 depending on whether |fill| is 0 or not.
 */
static int
addr_expand(unsigned char *addr, const ASN1_BIT_STRING *bs, const int length,
    uint8_t fill)
{
  if (bs->length < 0 || bs->length > length)
    return 0;

  if (fill != 0)
    fill = 0xff;

  if (bs->length > 0) {
    /* XXX - shouldn't this check ASN1_STRING_FLAG_BITS_LEFT? */
    uint8_t unused_bits = bs->flags & 7;
    uint8_t mask = (1 << unused_bits) - 1;

    memcpy(addr, bs->data, bs->length);

    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: 8 * length - unused bits.
 */
#define addr_prefix_len(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;
  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)
      continue;
    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)
{
  const IPAddressOrRange *aor;
  const ASN1_BIT_STRING *prefix;
  const IPAddressRange *range;
  int i;

  for (i = 0; i < sk_IPAddressOrRange_num(aors); i++) {
    aor = sk_IPAddressOrRange_value(aors, i);

    BIO_printf(out, "%*s", indent, "");

    switch (aor->type) {
    case IPAddressOrRange_addressPrefix:
      prefix = aor->u.addressPrefix;

      if (!i2r_address(out, afi, 0x00, prefix))
        return 0;
      BIO_printf(out, "/%d\n", addr_prefix_len(prefix));
      continue;
    case IPAddressOrRange_addressRange:
      range = aor->u.addressRange;

      if (!i2r_address(out, afi, 0x00, range->min))
        return 0;
      BIO_puts(out, "-");
      if (!i2r_address(out, afi, 0xff, range->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;
  IPAddressFamily *af;
  uint16_t afi;
  uint8_t safi;
  int i, safi_is_set;

  for (i = 0; i < sk_IPAddressFamily_num(addr); i++) {
    af = sk_IPAddressFamily_value(addr, i);

    if (!IPAddressFamily_afi_safi(af, &afi, &safi, &safi_is_set))
      goto print_addresses;

    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 (safi_is_set) {
      switch (safi) {
      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)", safi);
        break;
      }
    }

 print_addresses:
    switch (IPAddressFamily_type(af)) {
    case IPAddressChoice_inherit:
      BIO_puts(out, ": inherit\n");
      break;
    case IPAddressChoice_addressesOrRanges:
      BIO_puts(out, ":\n");
      if (!i2r_IPAddressOrRanges(out, indent + 2,
          IPAddressFamily_addressesOrRanges(af), afi))
        return 0;
      break;
    /* XXX - how should we handle -1 here? */
    }
  }
  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 prefix_len_a = 0, prefix_len_b = 0;
  int r;

  switch (a->type) {
  case IPAddressOrRange_addressPrefix:
    if (!addr_expand(addr_a, a->u.addressPrefix, length, 0x00))
      return -1;
    prefix_len_a = addr_prefix_len(a->u.addressPrefix);
    break;
  case IPAddressOrRange_addressRange:
    if (!addr_expand(addr_a, a->u.addressRange->min, length, 0x00))
      return -1;
    prefix_len_a = length * 8;
    break;
  }

  switch (b->type) {
  case IPAddressOrRange_addressPrefix:
    if (!addr_expand(addr_b, b->u.addressPrefix, length, 0x00))
      return -1;
    prefix_len_b = addr_prefix_len(b->u.addressPrefix);
    break;
  case IPAddressOrRange_addressRange:
    if (!addr_expand(addr_b, b->u.addressRange->min, length, 0x00))
      return -1;
    prefix_len_b = length * 8;
    break;
  }

  if ((r = memcmp(addr_a, addr_b, length)) != 0)
    return r;
  else
    return prefix_len_a - prefix_len_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.
 *
 * It's the caller's responsibility to ensure that min <= max.
 */
static int
range_should_be_prefix(const unsigned char *min, const unsigned char *max,
    const int length)
{
  unsigned char mask;
  int i, j;

  for (i = 0; i < length && min[i] == max[i]; i++)
    continue;
  for (j = length - 1; j >= 0 && min[j] == 0x00 && max[j] == 0xff; j--)
    continue;
  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;
}

/*
 * Fill IPAddressOrRange with bit string encoding of a prefix - RFC 3779, 2.1.1.
 */
static int
make_addressPrefix(IPAddressOrRange **out_aor, uint8_t *addr, uint32_t afi,
    int prefix_len)
{
  IPAddressOrRange *aor = NULL;
  int afi_len, max_len, num_bits, num_octets;
  uint8_t unused_bits;

  if (prefix_len < 0)
    goto err;

  max_len = 16;
  if ((afi_len = length_from_afi(afi)) > 0)
    max_len = afi_len;
  if (prefix_len > 8 * max_len)
    goto err;

  num_octets = (prefix_len + 7) / 8;
  num_bits = prefix_len % 8;

  unused_bits = 0;
  if (num_bits > 0)
    unused_bits = 8 - num_bits;

  if ((aor = IPAddressOrRange_new()) == NULL)
    goto err;

  aor->type = IPAddressOrRange_addressPrefix;

  if ((aor->u.addressPrefix = ASN1_BIT_STRING_new()) == NULL)
    goto err;
  if (!ASN1_BIT_STRING_set(aor->u.addressPrefix, addr, num_octets))
    goto err;
  if (!asn1_abs_set_unused_bits(aor->u.addressPrefix, unused_bits))
    goto err;

  *out_aor = aor;
  return 1;

 err:
  IPAddressOrRange_free(aor);
  return 0;
}

static uint8_t
count_trailing_zeroes(uint8_t octet)
{
  uint8_t count = 0;

  if (octet == 0)
    return 8;

  while ((octet & (1 << count)) == 0)
    count++;

  return count;
}

static int
trim_end_u8(CBS *cbs, uint8_t trim)
{
  uint8_t octet;

  while (CBS_len(cbs) > 0) {
    if (!CBS_peek_last_u8(cbs, &octet))
      return 0;
    if (octet != trim)
      return 1;
    if (!CBS_get_last_u8(cbs, &octet))
      return 0;
  }

  return 1;
}

/*
 * Populate IPAddressOrRange with bit string encoding of a range, see
 * RFC 3779, 2.1.2.
 */
static int
make_addressRange(IPAddressOrRange **out_aor, uint8_t *min, uint8_t *max,
    uint32_t afi, int length)
{
  IPAddressOrRange *aor = NULL;
  IPAddressRange *range;
  int prefix_len;
  CBS cbs;
  size_t max_len, min_len;
  uint8_t unused_bits_min, unused_bits_max;
  uint8_t octet;

  if (memcmp(min, max, length) > 0)
    goto err;

  /*
   * RFC 3779, 2.2.3.6 - a range that can be expressed as a prefix
   * must be encoded as a prefix.
   */

  if ((prefix_len = range_should_be_prefix(min, max, length)) >= 0)
    return make_addressPrefix(out_aor, min, afi, prefix_len);

  /*
   * The bit string representing min is formed by removing all its
   * trailing zero bits, so remove all trailing zero octets and count
   * the trailing zero bits of the last octet.
   */

  CBS_init(&cbs, min, length);

  if (!trim_end_u8(&cbs, 0x00))
    goto err;

  unused_bits_min = 0;
  if ((min_len = CBS_len(&cbs)) > 0) {
    if (!CBS_peek_last_u8(&cbs, &octet))
      goto err;

    unused_bits_min = count_trailing_zeroes(octet);
  }

  /*
   * The bit string representing max is formed by removing all its
   * trailing one bits, so remove all trailing 0xff octets and count
   * the trailing ones of the last octet.
   */

  CBS_init(&cbs, max, length);

  if (!trim_end_u8(&cbs, 0xff))
    goto err;

  unused_bits_max = 0;
  if ((max_len = CBS_len(&cbs)) > 0) {
    if (!CBS_peek_last_u8(&cbs, &octet))
      goto err;

    unused_bits_max = count_trailing_zeroes(octet + 1);
  }

  /*
   * Populate IPAddressOrRange.
   */

  if ((aor = IPAddressOrRange_new()) == NULL)
    goto err;

  aor->type = IPAddressOrRange_addressRange;

  if ((range = aor->u.addressRange = IPAddressRange_new()) == NULL)
    goto err;

  if (!ASN1_BIT_STRING_set(range->min, min, min_len))
    goto err;
  if (!asn1_abs_set_unused_bits(range->min, unused_bits_min))
    goto err;

  if (!ASN1_BIT_STRING_set(range->max, max, max_len))
    goto err;
  if (!asn1_abs_set_unused_bits(range->max, unused_bits_max))
    goto err;

  *out_aor = 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 *af = NULL;
  CBB cbb;
  CBS cbs;
  uint8_t *key = NULL;
  size_t keylen;
  int i;

  if (!CBB_init(&cbb, 0))
    goto err;

  /* XXX - should afi <= 65535 and *safi <= 255 be checked here? */

  if (!CBB_add_u16(&cbb, afi))
    goto err;
  if (safi != NULL) {
    if (!CBB_add_u8(&cbb, *safi))
      goto err;
  }

  if (!CBB_finish(&cbb, &key, &keylen))
    goto err;

  for (i = 0; i < sk_IPAddressFamily_num(addr); i++) {
    af = sk_IPAddressFamily_value(addr, i);

    CBS_init(&cbs, af->addressFamily->data,
        af->addressFamily->length);
    if (CBS_mem_equal(&cbs, key, keylen))
      goto done;
  }

  if ((af = IPAddressFamily_new()) == NULL)
    goto err;
  if (!ASN1_OCTET_STRING_set(af->addressFamily, key, keylen))
    goto err;
  if (!sk_IPAddressFamily_push(addr, af))
    goto err;

 done:
  free(key);

  return af;

 err:
  CBB_cleanup(&cbb);
  free(key);
  IPAddressFamily_free(af);

  return NULL;
}

/*
 * Add an inheritance element.
 */
int
X509v3_addr_add_inherit(IPAddrBlocks *addr, const unsigned afi,
    const unsigned *safi)
{
  IPAddressFamily *af;

  if ((af = make_IPAddressFamily(addr, afi, safi)) == NULL)
    return 0;

  return IPAddressFamily_set_inheritance(af);
}

/*
 * Construct an IPAddressOrRange sequence, or return an existing one.
 */
static IPAddressOrRanges *
make_prefix_or_range(IPAddrBlocks *addr, const unsigned afi,
    const unsigned *safi)
{
  IPAddressFamily *af;
  IPAddressOrRanges *aors = NULL;

  if ((af = make_IPAddressFamily(addr, afi, safi)) == NULL)
    return NULL;

  if (IPAddressFamily_inheritance(af) != NULL)
    return NULL;

  if ((aors = IPAddressFamily_addressesOrRanges(af)) != 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;
  }

  af->ipAddressChoice->type = IPAddressChoice_addressesOrRanges;
  af->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 prefix_len)
{
  IPAddressOrRanges *aors;
  IPAddressOrRange *aor;

  if ((aors = make_prefix_or_range(addr, afi, safi)) == NULL)
    return 0;

  if (!make_addressPrefix(&aor, a, afi, prefix_len))
    return 0;

  if (sk_IPAddressOrRange_push(aors, aor) <= 0) {
    IPAddressOrRange_free(aor);
    return 0;
  }

  return 1;
}

/*
 * Add a range.
 */
int
X509v3_addr_add_range(IPAddrBlocks *addr, const unsigned afi,
    const unsigned *safi, unsigned char *min, unsigned char *max)
{
  IPAddressOrRanges *aors;
  IPAddressOrRange *aor;
  int length;

  if ((aors = make_prefix_or_range(addr, afi, safi)) == NULL)
    return 0;

  length = length_from_afi(afi);

  if (!make_addressRange(&aor, min, max, afi, length))
    return 0;

  if (sk_IPAddressOrRange_push(aors, aor) <= 0) {
    IPAddressOrRange_free(aor);
    return 0;
  }

  return 1;
}

static int
extract_min_max_bitstr(IPAddressOrRange *aor, ASN1_BIT_STRING **out_min,
    ASN1_BIT_STRING **out_max)
{
  switch (aor->type) {
  case IPAddressOrRange_addressPrefix:
    *out_min = *out_max = aor->u.addressPrefix;
    return 1;
  case IPAddressOrRange_addressRange:
    *out_min = aor->u.addressRange->min;
    *out_max = aor->u.addressRange->max;
    return 1;
  default:
    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)
{
  ASN1_BIT_STRING *min_bitstr, *max_bitstr;

  if (aor == NULL || min == NULL || max == NULL)
    return 0;

  if (!extract_min_max_bitstr(aor, &min_bitstr, &max_bitstr))
    return 0;

  if (!addr_expand(min, min_bitstr, length, 0))
    return 0;

  return addr_expand(max, max_bitstr, length, 1);
}

/*
 * 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_len;

  if ((afi_len = length_from_afi(afi)) == 0)
    return 0;

  if (length < afi_len)
    return 0;

  if (!extract_min_max(aor, min, max, afi_len))
    return 0;

  return afi_len;
}

/*
 * 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];
  IPAddressFamily *af;
  IPAddressOrRanges *aors;
  IPAddressOrRange *aor, *aor_a, *aor_b;
  int i, j, k, length;

  /*
   * 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);

    /* Check that both have valid AFIs before comparing them. */
    if (!IPAddressFamily_afi_is_valid(a))
      return 0;
    if (!IPAddressFamily_afi_is_valid(b))
      return 0;

    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++) {
    af = sk_IPAddressFamily_value(addr, i);

    if (!IPAddressFamily_afi_length(af, &length))
      return 0;

    /*
     * If this family has an inheritance element, it is canonical.
     */
    if (IPAddressFamily_inheritance(af) != NULL)
      continue;

    /*
     * If this family has neither an inheritance element nor an
     * addressesOrRanges, we don't know what this is.
     */
    if ((aors = IPAddressFamily_addressesOrRanges(af)) == NULL)
      return 0;

    if (sk_IPAddressOrRange_num(aors) == 0)
      return 0;

    for (j = 0; j < sk_IPAddressOrRange_num(aors) - 1; j++) {
      aor_a = sk_IPAddressOrRange_value(aors, j);
      aor_b = sk_IPAddressOrRange_value(aors, j + 1);

      if (!extract_min_max(aor_a, a_min, a_max, length) ||
          !extract_min_max(aor_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--)
        continue;
      if (memcmp(a_max, b_min, length) >= 0)
        return 0;

      /*
       * Check for range that should be expressed as a prefix.
       */
      if (aor_a->type == IPAddressOrRange_addressPrefix)
        continue;

      if (range_should_be_prefix(a_min, a_max, length) >= 0)
        return 0;
    }

    /*
     * Check final range to see if it's inverted or should be a
     * prefix.
     */
    aor = sk_IPAddressOrRange_value(aors, j);
    if (aor->type == IPAddressOrRange_addressRange) {
      if (!extract_min_max(aor, a_min, a_max, length))
        return 0;
      if (memcmp(a_min, a_max, length) > 0)
        return 0;
      if (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)
{
  IPAddressOrRange *a, *b, *merged;
  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];
  int i, j, length;

  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++) {
    a = sk_IPAddressOrRange_value(aors, i);
    b = sk_IPAddressOrRange_value(aors, i + 1);

    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--)
      continue;

    if (memcmp(a_max, b_min, length) != 0)
      continue;

    if (!make_addressRange(&merged, a_min, b_max, afi, length))
      return 0;
    sk_IPAddressOrRange_set(aors, i, merged);
    (void)sk_IPAddressOrRange_delete(aors, i + 1);
    IPAddressOrRange_free(a);
    IPAddressOrRange_free(b);
    i--;
  }

  /*
   * Check for inverted final range.
   */
  a = sk_IPAddressOrRange_value(aors, i);
  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)
      return 0;
  }

  return 1;
}

/*
 * Whack an IPAddrBlocks extension into canonical form.
 */
int
X509v3_addr_canonize(IPAddrBlocks *addr)
{
  IPAddressFamily *af;
  IPAddressOrRanges *aors;
  uint16_t afi;
  int i;

  for (i = 0; i < sk_IPAddressFamily_num(addr); i++) {
    af = sk_IPAddressFamily_value(addr, i);

    /* Check AFI/SAFI here - IPAddressFamily_cmp() can't error. */
    if (!IPAddressFamily_afi(af, &afi))
      return 0;

    if ((aors = IPAddressFamily_addressesOrRanges(af)) == NULL)
      continue;

    if (!IPAddressOrRanges_canonize(aors, afi))
      return 0;
  }

  (void)sk_IPAddressFamily_set_cmp_func(addr, IPAddressFamily_cmp);
  sk_IPAddressFamily_sort(addr);

  return X509v3_addr_is_canonical(addr);
}

/*
 * 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) {
    X509V3error(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;
    const char *errstr;
    int prefix_len, i1, i2, delim, length;

    if (!name_cmp(val->name, "IPv4")) {
      afi = IANA_AFI_IPV4;
    } else if (!name_cmp(val->name, "IPv6")) {
      afi = IANA_AFI_IPV6;
    } else if (!name_cmp(val->name, "IPv4-SAFI")) {
      afi = IANA_AFI_IPV4;
      safi = &safi_;
    } else if (!name_cmp(val->name, "IPv6-SAFI")) {
      afi = IANA_AFI_IPV6;
      safi = &safi_;
    } else {
      X509V3error(X509V3_R_EXTENSION_NAME_ERROR);
      X509V3_conf_err(val);
      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 strdup() so we can null-terminate
     * the other input values.
     */
    if (safi != NULL) {
      unsigned long parsed_safi;
      int saved_errno = errno;

      errno = 0;
      parsed_safi = strtoul(val->value, &t, 0);

      /* Value must be present, then a tab, space or colon. */
      if (val->value[0] == '\0' ||
          (*t != '\t' && *t != ' ' && *t != ':')) {
        X509V3error(X509V3_R_INVALID_SAFI);
        X509V3_conf_err(val);
        goto err;
      }
      /* Range and overflow check. */
      if ((errno == ERANGE && parsed_safi == ULONG_MAX) ||
          parsed_safi > 0xff) {
        X509V3error(X509V3_R_INVALID_SAFI);
        X509V3_conf_err(val);
        goto err;
      }
      errno = saved_errno;

      *safi = parsed_safi;

      /* Check possible whitespace is followed by a colon. */
      t += strspn(t, " \t");
      if (*t != ':') {
        X509V3error(X509V3_R_INVALID_SAFI);
        X509V3_conf_err(val);
        goto err;
      }

      /* Skip over colon. */
      t++;

      /* Then over any trailing whitespace. */
      t += strspn(t, " \t");

      s = strdup(t);
    } else {
      s = strdup(val->value);
    }
    if (s == NULL) {
      X509V3error(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)) {
        X509V3error(X509V3_R_INVALID_INHERITANCE);
        X509V3_conf_err(val);
        goto err;
      }
      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) {
      X509V3error(X509V3_R_INVALID_IPADDRESS);
      X509V3_conf_err(val);
      goto err;
    }

    switch (delim) {
    case '/':
      /* length contains the size of the address in bytes. */
      if (length != 4 && length != 16)
        goto err;
      prefix_len = strtonum(s + i2, 0, 8 * length, &errstr);
      if (errstr != NULL) {
        X509V3error(X509V3_R_EXTENSION_VALUE_ERROR);
        X509V3_conf_err(val);
        goto err;
      }
      if (!X509v3_addr_add_prefix(addr, afi, safi, min,
          prefix_len)) {
        X509V3error(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') {
        X509V3error(X509V3_R_EXTENSION_VALUE_ERROR);
        X509V3_conf_err(val);
        goto err;
      }
      if (a2i_ipadd(max, s + i1) != length) {
        X509V3error(X509V3_R_INVALID_IPADDRESS);
        X509V3_conf_err(val);
        goto err;
      }
      if (memcmp(min, max, length_from_afi(afi)) > 0) {
        X509V3error(X509V3_R_EXTENSION_VALUE_ERROR);
        X509V3_conf_err(val);
        goto err;
      }
      if (!X509v3_addr_add_range(addr, afi, safi, min, max)) {
        X509V3error(ERR_R_MALLOC_FAILURE);
        goto err;
      }
      break;
    case '\0':
      if (!X509v3_addr_add_prefix(addr, afi, safi, min,
          length * 8)) {
        X509V3error(ERR_R_MALLOC_FAILURE);
        goto err;
      }
      break;
    default:
      X509V3error(X509V3_R_EXTENSION_VALUE_ERROR);
      X509V3_conf_err(val);
      goto err;
    }

    free(s);
    s = NULL;
  }

  /*
   * Canonize the result, then we're done.
   */
  if (!X509v3_addr_canonize(addr))
    goto err;
  return addr;

 err:
  free(s);
  sk_IPAddressFamily_pop_free(addr, IPAddressFamily_free);
  return NULL;
}

/*
 * OpenSSL dispatch
 */
const X509V3_EXT_METHOD v3_addr = {
  .ext_nid = NID_sbgp_ipAddrBlock,
  .ext_flags = 0,
  .it = &IPAddrBlocks_it,
  .ext_new = NULL,
  .ext_free = NULL,
  .d2i = NULL,
  .i2d = NULL,
  .i2s = NULL,
  .s2i = NULL,
  .i2v = NULL,
  .v2i = v2i_IPAddrBlocks,
  .i2r = i2r_IPAddrBlocks,
  .r2i = NULL,
  .usr_data = NULL,
};

/*
 * Figure out whether extension uses inheritance.
 */
int
X509v3_addr_inherits(IPAddrBlocks *addr)
{
  IPAddressFamily *af;
  int i;

  if (addr == NULL)
    return 0;

  for (i = 0; i < sk_IPAddressFamily_num(addr); i++) {
    af = sk_IPAddressFamily_value(addr, i);

    if (IPAddressFamily_inheritance(af) != NULL)
      return 1;
  }

  return 0;
}

/*
 * Figure out whether parent contains child.
 *
 * This only works correctly if both parent and child are in canonical form.
 */
static int
addr_contains(IPAddressOrRanges *parent, IPAddressOrRanges *child, int length)
{
  IPAddressOrRange *child_aor, *parent_aor;
  uint8_t parent_min[ADDR_RAW_BUF_LEN], parent_max[ADDR_RAW_BUF_LEN];
  uint8_t child_min[ADDR_RAW_BUF_LEN], child_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++) {
    child_aor = sk_IPAddressOrRange_value(child, c);

    if (!extract_min_max(child_aor, child_min, child_max, length))
      return 0;

    for (;; p++) {
      if (p >= sk_IPAddressOrRange_num(parent))
        return 0;

      parent_aor = sk_IPAddressOrRange_value(parent, p);

      if (!extract_min_max(parent_aor, parent_min, parent_max,
          length))
        return 0;

      if (memcmp(parent_max, child_max, length) < 0)
        continue;
      if (memcmp(parent_min, child_min, length) > 0)
        return 0;
      break;
    }
  }

  return 1;
}

/*
 * Test whether |child| is a subset of |parent|.
 */
int
X509v3_addr_subset(IPAddrBlocks *child, IPAddrBlocks *parent)
{
  IPAddressFamily *child_af, *parent_af;
  IPAddressOrRanges *child_aor, *parent_aor;
  int i, length;

  if (child == NULL || child == parent)
    return 1;
  if (parent == NULL)
    return 0;

  if (X509v3_addr_inherits(child) || X509v3_addr_inherits(parent))
    return 0;

  for (i = 0; i < sk_IPAddressFamily_num(child); i++) {
    child_af = sk_IPAddressFamily_value(child, i);

    parent_af = IPAddressFamily_find_in_parent(parent, child_af);
    if (parent_af == NULL)
      return 0;

    if (!IPAddressFamily_afi_length(parent_af, &length))
      return 0;

    child_aor = IPAddressFamily_addressesOrRanges(child_af);
    parent_aor = IPAddressFamily_addressesOrRanges(parent_af);

    if (!addr_contains(parent_aor, child_aor, length))
      return 0;
  }
  return 1;
}

static int
verify_error(X509_STORE_CTX *ctx, X509 *cert, int error, int depth)
{
  if (ctx == NULL)
    return 0;

  ctx->current_cert = cert;
  ctx->error = error;
  ctx->error_depth = depth;

  return ctx->verify_cb(0, ctx);
}

/*
 * 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, *parent = NULL;
  IPAddressFamily *child_af, *parent_af;
  IPAddressOrRanges *child_aor, *parent_aor;
  X509 *cert = NULL;
  int depth = -1;
  int i;
  unsigned int length;
  int ret = 1;

  /* We need a non-empty chain to test against. */
  if (sk_X509_num(chain) <= 0)
    goto err;
  /* We need either a store ctx or an extension to work with. */
  if (ctx == NULL && ext == NULL)
    goto err;
  /* If there is a store ctx, it needs a verify_cb. */
  if (ctx != NULL && ctx->verify_cb == NULL)
    goto err;

  /*
   * Figure out where to start. If we don't have an extension to check,
   * (either extracted from the leaf or passed by the caller), we're done.
   * Otherwise, check canonical form and set up for walking up the chain.
   */
  if (ext == NULL) {
    depth = 0;
    cert = sk_X509_value(chain, depth);
    if ((X509_get_extension_flags(cert) & EXFLAG_INVALID) != 0)
      goto done;
    if ((ext = cert->rfc3779_addr) == NULL)
      goto done;
  } else if (!X509v3_addr_is_canonical(ext)) {
    if ((ret = verify_error(ctx, cert,
        X509_V_ERR_INVALID_EXTENSION, depth)) == 0)
      goto done;
  }

  (void)sk_IPAddressFamily_set_cmp_func(ext, IPAddressFamily_cmp);
  if ((child = sk_IPAddressFamily_dup(ext)) == NULL) {
    X509V3error(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 (depth++; depth < sk_X509_num(chain); depth++) {
    cert = sk_X509_value(chain, depth);

    if ((X509_get_extension_flags(cert) & EXFLAG_INVALID) != 0) {
      if ((ret = verify_error(ctx, cert,
          X509_V_ERR_INVALID_EXTENSION, depth)) == 0)
        goto done;
    }

    if ((parent = cert->rfc3779_addr) == NULL) {
      for (i = 0; i < sk_IPAddressFamily_num(child); i++) {
        child_af = sk_IPAddressFamily_value(child, i);

        if (IPAddressFamily_inheritance(child_af) !=
            NULL)
          continue;

        if ((ret = verify_error(ctx, cert,
            X509_V_ERR_UNNESTED_RESOURCE, depth)) == 0)
          goto done;
        break;
      }
      continue;
    }

    /*
     * Check that the child's resources are covered by the parent.
     * Each covered resource is replaced with the parent's resource
     * covering it, so the next iteration will check that the
     * parent's resources are covered by the grandparent.
     */
    for (i = 0; i < sk_IPAddressFamily_num(child); i++) {
      child_af = sk_IPAddressFamily_value(child, i);

      if ((parent_af = IPAddressFamily_find_in_parent(parent,
          child_af)) == NULL) {
        /*
         * If we have no match in the parent and the
         * child inherits, that's fine.
         */
        if (IPAddressFamily_inheritance(child_af) !=
            NULL)
          continue;

        /* Otherwise the child isn't covered. */
        if ((ret = verify_error(ctx, cert,
            X509_V_ERR_UNNESTED_RESOURCE, depth)) == 0)
          goto done;
        break;
      }

      /* Parent inherits, nothing to do. */
      if (IPAddressFamily_inheritance(parent_af) != NULL)
        continue;

      /* Child inherits. Use parent's address family. */
      if (IPAddressFamily_inheritance(child_af) != NULL) {
        sk_IPAddressFamily_set(child, i, parent_af);
        continue;
      }

      child_aor = IPAddressFamily_addressesOrRanges(child_af);
      parent_aor =
          IPAddressFamily_addressesOrRanges(parent_af);

      /*
       * Child and parent are canonical and neither inherits.
       * If either addressesOrRanges is NULL, something's
       * very wrong.
       */
      if (child_aor == NULL || parent_aor == NULL)
        goto err;

      if (!IPAddressFamily_afi_length(child_af, &length))
        goto err;

      /* Now check containment and replace or error. */
      if (addr_contains(parent_aor, child_aor, length)) {
        sk_IPAddressFamily_set(child, i, parent_af);
        continue;
      }

      if ((ret = verify_error(ctx, cert,
          X509_V_ERR_UNNESTED_RESOURCE, depth)) == 0)
        goto done;
    }
  }

  /*
   * Trust anchor can't inherit.
   */
  if ((parent = cert->rfc3779_addr) != NULL) {
    for (i = 0; i < sk_IPAddressFamily_num(parent); i++) {
      parent_af = sk_IPAddressFamily_value(parent, i);

      if (IPAddressFamily_inheritance(parent_af) == NULL)
        continue;

      if ((ret = verify_error(ctx, cert,
          X509_V_ERR_UNNESTED_RESOURCE, depth)) == 0)
        goto done;
    }
  }

 done:
  sk_IPAddressFamily_free(child);
  return ret;

 err:
  sk_IPAddressFamily_free(child);

  if (ctx != NULL)
    ctx->error = X509_V_ERR_UNSPECIFIED;

  return 0;
}

/*
 * RFC 3779 2.3 path validation -- called from X509_verify_cert().
 */
int
X509v3_addr_validate_path(X509_STORE_CTX *ctx)
{
  if (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 (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 */

Coverage Report

Created: 2022-08-24 06:30