/*      $OpenBSD: x509_asid.c,v 1.46 2025/05/10 05:54:39 tb Exp $ */
/*
 * Contributed to the OpenSSL Project by the American Registry for
 * Internet Numbers ("ARIN").
 */
/* ====================================================================
 * Copyright (c) 2006-2018 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 3.2.
 */

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

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

#include "err_local.h"
#include "x509_local.h"

#ifndef OPENSSL_NO_RFC3779

static const ASN1_TEMPLATE ASRange_seq_tt[] = {
        {
                .flags = 0,
                .tag = 0,
                .offset = offsetof(ASRange, min),
                .field_name = "min",
                .item = &ASN1_INTEGER_it,
        },
        {
                .flags = 0,
                .tag = 0,
                .offset = offsetof(ASRange, max),
                .field_name = "max",
                .item = &ASN1_INTEGER_it,
        },
};

const ASN1_ITEM ASRange_it = {
        .itype = ASN1_ITYPE_SEQUENCE,
        .utype = V_ASN1_SEQUENCE,
        .templates = ASRange_seq_tt,
        .tcount = sizeof(ASRange_seq_tt) / sizeof(ASN1_TEMPLATE),
        .funcs = NULL,
        .size = sizeof(ASRange),
        .sname = "ASRange",
};
LCRYPTO_ALIAS(ASRange_it);

static const ASN1_TEMPLATE ASIdOrRange_ch_tt[] = {
        {
                .flags = 0,
                .tag = 0,
                .offset = offsetof(ASIdOrRange, u.id),
                .field_name = "u.id",
                .item = &ASN1_INTEGER_it,
        },
        {
                .flags = 0,
                .tag = 0,
                .offset = offsetof(ASIdOrRange, u.range),
                .field_name = "u.range",
                .item = &ASRange_it,
        },
};

const ASN1_ITEM ASIdOrRange_it = {
        .itype = ASN1_ITYPE_CHOICE,
        .utype = offsetof(ASIdOrRange, type),
        .templates = ASIdOrRange_ch_tt,
        .tcount = sizeof(ASIdOrRange_ch_tt) / sizeof(ASN1_TEMPLATE),
        .funcs = NULL,
        .size = sizeof(ASIdOrRange),
        .sname = "ASIdOrRange",
};
LCRYPTO_ALIAS(ASIdOrRange_it);

static const ASN1_TEMPLATE ASIdentifierChoice_ch_tt[] = {
        {
                .flags = 0,
                .tag = 0,
                .offset = offsetof(ASIdentifierChoice, u.inherit),
                .field_name = "u.inherit",
                .item = &ASN1_NULL_it,
        },
        {
                .flags = ASN1_TFLG_SEQUENCE_OF,
                .tag = 0,
                .offset = offsetof(ASIdentifierChoice, u.asIdsOrRanges),
                .field_name = "u.asIdsOrRanges",
                .item = &ASIdOrRange_it,
        },
};

const ASN1_ITEM ASIdentifierChoice_it = {
        .itype = ASN1_ITYPE_CHOICE,
        .utype = offsetof(ASIdentifierChoice, type),
        .templates = ASIdentifierChoice_ch_tt,
        .tcount = sizeof(ASIdentifierChoice_ch_tt) / sizeof(ASN1_TEMPLATE),
        .funcs = NULL,
        .size = sizeof(ASIdentifierChoice),
        .sname = "ASIdentifierChoice",
};
LCRYPTO_ALIAS(ASIdentifierChoice_it);

static const ASN1_TEMPLATE ASIdentifiers_seq_tt[] = {
        {
                .flags = ASN1_TFLG_EXPLICIT | ASN1_TFLG_OPTIONAL,
                .tag = 0,
                .offset = offsetof(ASIdentifiers, asnum),
                .field_name = "asnum",
                .item = &ASIdentifierChoice_it,
        },
        {
                .flags = ASN1_TFLG_EXPLICIT | ASN1_TFLG_OPTIONAL,
                .tag = 1,
                .offset = offsetof(ASIdentifiers, rdi),
                .field_name = "rdi",
                .item = &ASIdentifierChoice_it,
        },
};

const ASN1_ITEM ASIdentifiers_it = {
        .itype = ASN1_ITYPE_SEQUENCE,
        .utype = V_ASN1_SEQUENCE,
        .templates = ASIdentifiers_seq_tt,
        .tcount = sizeof(ASIdentifiers_seq_tt) / sizeof(ASN1_TEMPLATE),
        .funcs = NULL,
        .size = sizeof(ASIdentifiers),
        .sname = "ASIdentifiers",
};
LCRYPTO_ALIAS(ASIdentifiers_it);

ASRange *
d2i_ASRange(ASRange **a, const unsigned char **in, long len)
{
        return (ASRange *)ASN1_item_d2i((ASN1_VALUE **)a, in, len,
            &ASRange_it);
}
LCRYPTO_ALIAS(d2i_ASRange);

int
i2d_ASRange(ASRange *a, unsigned char **out)
{
        return ASN1_item_i2d((ASN1_VALUE *)a, out, &ASRange_it);
}
LCRYPTO_ALIAS(i2d_ASRange);

ASRange *
ASRange_new(void)
{
        return (ASRange *)ASN1_item_new(&ASRange_it);
}
LCRYPTO_ALIAS(ASRange_new);

void
ASRange_free(ASRange *a)
{
        ASN1_item_free((ASN1_VALUE *)a, &ASRange_it);
}
LCRYPTO_ALIAS(ASRange_free);

ASIdOrRange *
d2i_ASIdOrRange(ASIdOrRange **a, const unsigned char **in, long len)
{
        return (ASIdOrRange *)ASN1_item_d2i((ASN1_VALUE **)a, in, len,
            &ASIdOrRange_it);
}
LCRYPTO_ALIAS(d2i_ASIdOrRange);

int
i2d_ASIdOrRange(ASIdOrRange *a, unsigned char **out)
{
        return ASN1_item_i2d((ASN1_VALUE *)a, out, &ASIdOrRange_it);
}
LCRYPTO_ALIAS(i2d_ASIdOrRange);

ASIdOrRange *
ASIdOrRange_new(void)
{
        return (ASIdOrRange *)ASN1_item_new(&ASIdOrRange_it);
}
LCRYPTO_ALIAS(ASIdOrRange_new);

void
ASIdOrRange_free(ASIdOrRange *a)
{
        ASN1_item_free((ASN1_VALUE *)a, &ASIdOrRange_it);
}
LCRYPTO_ALIAS(ASIdOrRange_free);

ASIdentifierChoice *
d2i_ASIdentifierChoice(ASIdentifierChoice **a, const unsigned char **in,
    long len)
{
        return (ASIdentifierChoice *)ASN1_item_d2i((ASN1_VALUE **)a, in, len,
            &ASIdentifierChoice_it);
}
LCRYPTO_ALIAS(d2i_ASIdentifierChoice);

int
i2d_ASIdentifierChoice(ASIdentifierChoice *a, unsigned char **out)
{
        return ASN1_item_i2d((ASN1_VALUE *)a, out, &ASIdentifierChoice_it);
}
LCRYPTO_ALIAS(i2d_ASIdentifierChoice);

ASIdentifierChoice *
ASIdentifierChoice_new(void)
{
        return (ASIdentifierChoice *)ASN1_item_new(&ASIdentifierChoice_it);
}
LCRYPTO_ALIAS(ASIdentifierChoice_new);

void
ASIdentifierChoice_free(ASIdentifierChoice *a)
{
        ASN1_item_free((ASN1_VALUE *)a, &ASIdentifierChoice_it);
}
LCRYPTO_ALIAS(ASIdentifierChoice_free);

ASIdentifiers *
d2i_ASIdentifiers(ASIdentifiers **a, const unsigned char **in, long len)
{
        return (ASIdentifiers *)ASN1_item_d2i((ASN1_VALUE **)a, in, len,
            &ASIdentifiers_it);
}
LCRYPTO_ALIAS(d2i_ASIdentifiers);

int
i2d_ASIdentifiers(ASIdentifiers *a, unsigned char **out)
{
        return ASN1_item_i2d((ASN1_VALUE *)a, out, &ASIdentifiers_it);
}
LCRYPTO_ALIAS(i2d_ASIdentifiers);

ASIdentifiers *
ASIdentifiers_new(void)
{
        return (ASIdentifiers *)ASN1_item_new(&ASIdentifiers_it);
}
LCRYPTO_ALIAS(ASIdentifiers_new);

void
ASIdentifiers_free(ASIdentifiers *a)
{
        ASN1_item_free((ASN1_VALUE *)a, &ASIdentifiers_it);
}
LCRYPTO_ALIAS(ASIdentifiers_free);

/*
 * i2r method for an ASIdentifierChoice.
 */
static int
i2r_ASIdentifierChoice(BIO *out, ASIdentifierChoice *choice, int indent,
    const char *msg)
{
        int i;
        char *s;
        if (choice == NULL)
                return 1;
        BIO_printf(out, "%*s%s:\n", indent, "", msg);
        switch (choice->type) {
        case ASIdentifierChoice_inherit:
                BIO_printf(out, "%*sinherit\n", indent + 2, "");
                break;
        case ASIdentifierChoice_asIdsOrRanges:
                for (i = 0; i < sk_ASIdOrRange_num(choice->u.asIdsOrRanges);
                    i++) {
                        ASIdOrRange *aor =
                            sk_ASIdOrRange_value(choice->u.asIdsOrRanges, i);
                        switch (aor->type) {
                        case ASIdOrRange_id:
                                if ((s = i2s_ASN1_INTEGER(NULL, aor->u.id)) ==
                                    NULL)
                                        return 0;
                                BIO_printf(out, "%*s%s\n", indent + 2, "", s);
                                free(s);
                                break;
                        case ASIdOrRange_range:
                                if ((s = i2s_ASN1_INTEGER(NULL,
                                    aor->u.range->min)) == NULL)
                                        return 0;
                                BIO_printf(out, "%*s%s-", indent + 2, "", s);
                                free(s);
                                if ((s = i2s_ASN1_INTEGER(NULL,
                                    aor->u.range->max)) == NULL)
                                        return 0;
                                BIO_printf(out, "%s\n", s);
                                free(s);
                                break;
                        default:
                                return 0;
                        }
                }
                break;
        default:
                return 0;
        }
        return 1;
}

/*
 * i2r method for an ASIdentifier extension.
 */
static int
i2r_ASIdentifiers(const X509V3_EXT_METHOD *method, void *ext, BIO *out,
    int indent)
{
        ASIdentifiers *asid = ext;
        return (i2r_ASIdentifierChoice(out, asid->asnum, indent,
            "Autonomous System Numbers") &&
            i2r_ASIdentifierChoice(out, asid->rdi, indent,
            "Routing Domain Identifiers"));
}

/*
 * Sort comparison function for a sequence of ASIdOrRange elements.
 */
static int
ASIdOrRange_cmp(const ASIdOrRange *const *a_, const ASIdOrRange *const *b_)
{
        const ASIdOrRange *a = *a_, *b = *b_;

        /* XXX: these asserts need to be replaced */
        OPENSSL_assert((a->type == ASIdOrRange_id && a->u.id != NULL) ||
            (a->type == ASIdOrRange_range && a->u.range != NULL &&
             a->u.range->min != NULL && a->u.range->max != NULL));

        OPENSSL_assert((b->type == ASIdOrRange_id && b->u.id != NULL) ||
            (b->type == ASIdOrRange_range && b->u.range != NULL &&
             b->u.range->min != NULL && b->u.range->max != NULL));

        if (a->type == ASIdOrRange_id && b->type == ASIdOrRange_id)
                return ASN1_INTEGER_cmp(a->u.id, b->u.id);

        if (a->type == ASIdOrRange_range && b->type == ASIdOrRange_range) {
                int r = ASN1_INTEGER_cmp(a->u.range->min, b->u.range->min);
                return r != 0 ? r : ASN1_INTEGER_cmp(a->u.range->max,
                    b->u.range->max);
        }

        if (a->type == ASIdOrRange_id)
                return ASN1_INTEGER_cmp(a->u.id, b->u.range->min);
        else
                return ASN1_INTEGER_cmp(a->u.range->min, b->u.id);
}

/*
 * Add an inherit element.
 */
int
X509v3_asid_add_inherit(ASIdentifiers *asid, int which)
{
        ASIdentifierChoice **choice;
        ASIdentifierChoice *aic = NULL;
        int ret = 0;

        if (asid == NULL)
                goto err;

        switch (which) {
        case V3_ASID_ASNUM:
                choice = &asid->asnum;
                break;
        case V3_ASID_RDI:
                choice = &asid->rdi;
                break;
        default:
                goto err;
        }

        if (*choice != NULL) {
                if ((*choice)->type != ASIdentifierChoice_inherit)
                        goto err;
        } else {
                if ((aic = ASIdentifierChoice_new()) == NULL)
                        goto err;
                if ((aic->u.inherit = ASN1_NULL_new()) == NULL)
                        goto err;
                aic->type = ASIdentifierChoice_inherit;

                *choice = aic;
                aic = NULL;
        }

        ret = 1;

 err:
        ASIdentifierChoice_free(aic);

        return ret;
}
LCRYPTO_ALIAS(X509v3_asid_add_inherit);

static int
ASIdOrRanges_add_id_or_range(ASIdOrRanges *aors, ASN1_INTEGER *min,
    ASN1_INTEGER *max)
{
        ASIdOrRange *aor = NULL;
        ASRange *asr = NULL;
        int ret = 0;

        /* Preallocate since we must not fail after sk_ASIdOrRange_push(). */
        if (max != NULL) {
                if ((asr = ASRange_new()) == NULL)
                        goto err;
        }

        if ((aor = ASIdOrRange_new()) == NULL)
                goto err;
        if (sk_ASIdOrRange_push(aors, aor) <= 0)
                goto err;

        if (max == NULL) {
                aor->type = ASIdOrRange_id;
                aor->u.id = min;
        } else {
                ASN1_INTEGER_free(asr->min);
                asr->min = min;
                ASN1_INTEGER_free(asr->max);
                asr->max = max;

                aor->type = ASIdOrRange_range;
                aor->u.range = asr;
                asr = NULL;
        }

        aor = NULL;

        ret = 1;

 err:
        ASIdOrRange_free(aor);
        ASRange_free(asr);

        return ret;
}

/*
 * Add an ID or range to an ASIdentifierChoice.
 */
int
X509v3_asid_add_id_or_range(ASIdentifiers *asid, int which, ASN1_INTEGER *min,
    ASN1_INTEGER *max)
{
        ASIdentifierChoice **choice;
        ASIdentifierChoice *aic = NULL, *new_aic = NULL;
        int ret = 0;

        if (asid == NULL)
                goto err;

        switch (which) {
        case V3_ASID_ASNUM:
                choice = &asid->asnum;
                break;
        case V3_ASID_RDI:
                choice = &asid->rdi;
                break;
        default:
                goto err;
        }

        if ((aic = *choice) != NULL) {
                if (aic->type != ASIdentifierChoice_asIdsOrRanges)
                        goto err;
        } else {
                if ((aic = new_aic = ASIdentifierChoice_new()) == NULL)
                        goto err;
                aic->u.asIdsOrRanges = sk_ASIdOrRange_new(ASIdOrRange_cmp);
                if (aic->u.asIdsOrRanges == NULL)
                        goto err;
                aic->type = ASIdentifierChoice_asIdsOrRanges;
        }

        if (!ASIdOrRanges_add_id_or_range(aic->u.asIdsOrRanges, min, max))
                goto err;

        *choice = aic;
        aic = new_aic = NULL;

        ret = 1;

 err:
        ASIdentifierChoice_free(new_aic);

        return ret;
}
LCRYPTO_ALIAS(X509v3_asid_add_id_or_range);

/*
 * Extract min and max values from an ASIdOrRange.
 */
static int
extract_min_max(ASIdOrRange *aor, ASN1_INTEGER **min, ASN1_INTEGER **max)
{
        switch (aor->type) {
        case ASIdOrRange_id:
                *min = aor->u.id;
                *max = aor->u.id;
                return 1;
        case ASIdOrRange_range:
                *min = aor->u.range->min;
                *max = aor->u.range->max;
                return 1;
        }
        *min = NULL;
        *max = NULL;

        return 0;
}

/*
 * Check whether an ASIdentifierChoice is in canonical form.
 */
static int
ASIdentifierChoice_is_canonical(ASIdentifierChoice *choice)
{
        ASIdOrRange *a, *b;
        ASN1_INTEGER *a_min = NULL, *a_max = NULL, *b_min = NULL, *b_max = NULL;
        ASN1_INTEGER *a_max_plus_one = NULL;
        ASN1_INTEGER *orig;
        BIGNUM *bn = NULL;
        int i, ret = 0;

        /*
         * Empty element or inheritance is canonical.
         */
        if (choice == NULL || choice->type == ASIdentifierChoice_inherit)
                return 1;

        /*
         * If not a list, or if empty list, it's broken.
         */
        if (choice->type != ASIdentifierChoice_asIdsOrRanges ||
            sk_ASIdOrRange_num(choice->u.asIdsOrRanges) == 0)
                return 0;

        /*
         * It's a list, check it.
         */
        for (i = 0; i < sk_ASIdOrRange_num(choice->u.asIdsOrRanges) - 1; i++) {
                a = sk_ASIdOrRange_value(choice->u.asIdsOrRanges, i);
                b = sk_ASIdOrRange_value(choice->u.asIdsOrRanges, i + 1);

                if (!extract_min_max(a, &a_min, &a_max) ||
                    !extract_min_max(b, &b_min, &b_max))
                        goto done;

                /*
                 * Punt misordered list, overlapping start, or inverted range.
                 */
                if (ASN1_INTEGER_cmp(a_min, b_min) >= 0 ||
                    ASN1_INTEGER_cmp(a_min, a_max) > 0 ||
                    ASN1_INTEGER_cmp(b_min, b_max) > 0)
                        goto done;

                /*
                 * Calculate a_max + 1 to check for adjacency.
                 */
                if ((bn == NULL && (bn = BN_new()) == NULL) ||
                    ASN1_INTEGER_to_BN(a_max, bn) == NULL ||
                    !BN_add_word(bn, 1)) {
                        X509V3error(ERR_R_MALLOC_FAILURE);
                        goto done;
                }

                if ((a_max_plus_one =
                    BN_to_ASN1_INTEGER(bn, orig = a_max_plus_one)) == NULL) {
                        a_max_plus_one = orig;
                        X509V3error(ERR_R_MALLOC_FAILURE);
                        goto done;
                }

                /*
                 * Punt if adjacent or overlapping.
                 */
                if (ASN1_INTEGER_cmp(a_max_plus_one, b_min) >= 0)
                        goto done;
        }

        /*
         * Check for inverted range.
         */
        i = sk_ASIdOrRange_num(choice->u.asIdsOrRanges) - 1;
        a = sk_ASIdOrRange_value(choice->u.asIdsOrRanges, i);
        if (a != NULL && a->type == ASIdOrRange_range) {
                if (!extract_min_max(a, &a_min, &a_max) ||
                    ASN1_INTEGER_cmp(a_min, a_max) > 0)
                        goto done;
        }

        ret = 1;

 done:
        ASN1_INTEGER_free(a_max_plus_one);
        BN_free(bn);
        return ret;
}

/*
 * Check whether an ASIdentifier extension is in canonical form.
 */
int
X509v3_asid_is_canonical(ASIdentifiers *asid)
{
        return (asid == NULL ||
            (ASIdentifierChoice_is_canonical(asid->asnum) &&
             ASIdentifierChoice_is_canonical(asid->rdi)));
}
LCRYPTO_ALIAS(X509v3_asid_is_canonical);

/*
 * Whack an ASIdentifierChoice into canonical form.
 */
static int
ASIdentifierChoice_canonize(ASIdentifierChoice *choice)
{
        ASIdOrRange *a, *b;
        ASN1_INTEGER *a_min = NULL, *a_max = NULL, *b_min = NULL, *b_max = NULL;
        ASN1_INTEGER *a_max_plus_one = NULL;
        ASN1_INTEGER *orig;
        BIGNUM *bn = NULL;
        int i, ret = 0;

        /*
         * Nothing to do for empty element or inheritance.
         */
        if (choice == NULL || choice->type == ASIdentifierChoice_inherit)
                return 1;

        /*
         * If not a list, or if empty list, it's broken.
         */
        if (choice->type != ASIdentifierChoice_asIdsOrRanges ||
            sk_ASIdOrRange_num(choice->u.asIdsOrRanges) == 0) {
                X509V3error(X509V3_R_EXTENSION_VALUE_ERROR);
                return 0;
        }

        /*
         * We have a non-empty list.  Sort it.
         */
        sk_ASIdOrRange_sort(choice->u.asIdsOrRanges);

        /*
         * Now check for errors and suboptimal encoding, rejecting the
         * former and fixing the latter.
         */
        for (i = 0; i < sk_ASIdOrRange_num(choice->u.asIdsOrRanges) - 1; i++) {
                a = sk_ASIdOrRange_value(choice->u.asIdsOrRanges, i);
                b = sk_ASIdOrRange_value(choice->u.asIdsOrRanges, i + 1);

                if (!extract_min_max(a, &a_min, &a_max) ||
                    !extract_min_max(b, &b_min, &b_max))
                        goto done;

                /*
                 * Make sure we're properly sorted (paranoia).
                 */
                if (ASN1_INTEGER_cmp(a_min, b_min) > 0)
                        goto done;

                /*
                 * Punt inverted ranges.
                 */
                if (ASN1_INTEGER_cmp(a_min, a_max) > 0 ||
                    ASN1_INTEGER_cmp(b_min, b_max) > 0)
                        goto done;

                /*
                 * Check for overlaps.
                 */
                if (ASN1_INTEGER_cmp(a_max, b_min) >= 0) {
                        X509V3error(X509V3_R_EXTENSION_VALUE_ERROR);
                        goto done;
                }

                /*
                 * Calculate a_max + 1 to check for adjacency.
                 */
                if ((bn == NULL && (bn = BN_new()) == NULL) ||
                    ASN1_INTEGER_to_BN(a_max, bn) == NULL ||
                    !BN_add_word(bn, 1)) {
                        X509V3error(ERR_R_MALLOC_FAILURE);
                        goto done;
                }

                if ((a_max_plus_one =
                    BN_to_ASN1_INTEGER(bn, orig = a_max_plus_one)) == NULL) {
                        a_max_plus_one = orig;
                        X509V3error(ERR_R_MALLOC_FAILURE);
                        goto done;
                }

                /*
                 * If a and b are adjacent, merge them.
                 */
                if (ASN1_INTEGER_cmp(a_max_plus_one, b_min) == 0) {
                        ASRange *r;
                        switch (a->type) {
                        case ASIdOrRange_id:
                                if ((r = calloc(1, sizeof(*r))) == NULL) {
                                        X509V3error(ERR_R_MALLOC_FAILURE);
                                        goto done;
                                }
                                r->min = a_min;
                                r->max = b_max;
                                a->type = ASIdOrRange_range;
                                a->u.range = r;
                                break;
                        case ASIdOrRange_range:
                                ASN1_INTEGER_free(a->u.range->max);
                                a->u.range->max = b_max;
                                break;
                        }
                        switch (b->type) {
                        case ASIdOrRange_id:
                                b->u.id = NULL;
                                break;
                        case ASIdOrRange_range:
                                b->u.range->max = NULL;
                                break;
                        }
                        ASIdOrRange_free(b);
                        (void)sk_ASIdOrRange_delete(choice->u.asIdsOrRanges,
                            i + 1);
                        i--;
                        continue;
                }
        }

        /*
         * Check for final inverted range.
         */
        i = sk_ASIdOrRange_num(choice->u.asIdsOrRanges) - 1;
        a = sk_ASIdOrRange_value(choice->u.asIdsOrRanges, i);
        if (a != NULL && a->type == ASIdOrRange_range) {
                if (!extract_min_max(a, &a_min, &a_max) ||
                    ASN1_INTEGER_cmp(a_min, a_max) > 0)
                        goto done;
        }

        /* Paranoia */
        if (!ASIdentifierChoice_is_canonical(choice))
                goto done;

        ret = 1;

 done:
        ASN1_INTEGER_free(a_max_plus_one);
        BN_free(bn);
        return ret;
}

/*
 * Whack an ASIdentifier extension into canonical form.
 */
int
X509v3_asid_canonize(ASIdentifiers *asid)
{
        if (asid == NULL)
                return 1;

        if (!ASIdentifierChoice_canonize(asid->asnum))
                return 0;

        return ASIdentifierChoice_canonize(asid->rdi);
}
LCRYPTO_ALIAS(X509v3_asid_canonize);

/*
 * v2i method for an ASIdentifier extension.
 */
static void *
v2i_ASIdentifiers(const struct v3_ext_method *method, struct v3_ext_ctx *ctx,
    STACK_OF(CONF_VALUE)*values)
{
        ASN1_INTEGER *min = NULL, *max = NULL;
        ASIdentifiers *asid = NULL;
        int i;

        if ((asid = ASIdentifiers_new()) == 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);
                int i1 = 0, i2 = 0, i3 = 0, is_range = 0, which = 0;

                /*
                 * Figure out whether this is an AS or an RDI.
                 */
                if (!name_cmp(val->name, "AS")) {
                        which = V3_ASID_ASNUM;
                } else if (!name_cmp(val->name, "RDI")) {
                        which = V3_ASID_RDI;
                } else {
                        X509V3error(X509V3_R_EXTENSION_NAME_ERROR);
                        X509V3_conf_err(val);
                        goto err;
                }

                /*
                 * Handle inheritance.
                 */
                if (strcmp(val->value, "inherit") == 0) {
                        if (X509v3_asid_add_inherit(asid, which))
                                continue;
                        X509V3error(X509V3_R_INVALID_INHERITANCE);
                        X509V3_conf_err(val);
                        goto err;
                }

                /*
                 * Number, range, or mistake, pick it apart and figure out which
                 */
                i1 = strspn(val->value, "0123456789");
                if (val->value[i1] == '\0') {
                        is_range = 0;
                } else {
                        is_range = 1;
                        i2 = i1 + strspn(val->value + i1, " \t");
                        if (val->value[i2] != '-') {
                                X509V3error(X509V3_R_INVALID_ASNUMBER);
                                X509V3_conf_err(val);
                                goto err;
                        }
                        i2++;
                        i2 = i2 + strspn(val->value + i2, " \t");
                        i3 = i2 + strspn(val->value + i2, "0123456789");
                        if (val->value[i3] != '\0') {
                                X509V3error(X509V3_R_INVALID_ASRANGE);
                                X509V3_conf_err(val);
                                goto err;
                        }
                }

                /*
                 * Syntax is ok, read and add it.
                 */
                if (!is_range) {
                        if (!X509V3_get_value_int(val, &min)) {
                                X509V3error(ERR_R_MALLOC_FAILURE);
                                goto err;
                        }
                } else {
                        char *s = strdup(val->value);
                        if (s == NULL) {
                                X509V3error(ERR_R_MALLOC_FAILURE);
                                goto err;
                        }
                        s[i1] = '\0';
                        min = s2i_ASN1_INTEGER(NULL, s);
                        max = s2i_ASN1_INTEGER(NULL, s + i2);
                        free(s);
                        if (min == NULL || max == NULL) {
                                X509V3error(ERR_R_MALLOC_FAILURE);
                                goto err;
                        }
                        if (ASN1_INTEGER_cmp(min, max) > 0) {
                                X509V3error(X509V3_R_EXTENSION_VALUE_ERROR);
                                goto err;
                        }
                }
                if (!X509v3_asid_add_id_or_range(asid, which, min, max)) {
                        X509V3error(ERR_R_MALLOC_FAILURE);
                        goto err;
                }
                min = max = NULL;
        }

        /*
         * Canonize the result, then we're done.
         */
        if (!X509v3_asid_canonize(asid))
                goto err;
        return asid;

 err:
        ASIdentifiers_free(asid);
        ASN1_INTEGER_free(min);
        ASN1_INTEGER_free(max);
        return NULL;
}

/*
 * OpenSSL dispatch.
 */
static const X509V3_EXT_METHOD x509v3_ext_sbgp_autonomousSysNum = {
        .ext_nid = NID_sbgp_autonomousSysNum,
        .ext_flags = 0,
        .it = &ASIdentifiers_it,
        .ext_new = NULL,
        .ext_free = NULL,
        .d2i = NULL,
        .i2d = NULL,
        .i2s = NULL,
        .s2i = NULL,
        .i2v = NULL,
        .v2i = v2i_ASIdentifiers,
        .i2r = i2r_ASIdentifiers,
        .r2i = NULL,
        .usr_data = NULL,
};

const X509V3_EXT_METHOD *
x509v3_ext_method_sbgp_autonomousSysNum(void)
{
        return &x509v3_ext_sbgp_autonomousSysNum;
}

/*
 * Figure out whether extension uses inheritance.
 */
int
X509v3_asid_inherits(ASIdentifiers *asid)
{
        if (asid == NULL)
                return 0;

        if (asid->asnum != NULL) {
                if (asid->asnum->type == ASIdentifierChoice_inherit)
                        return 1;
        }

        if (asid->rdi != NULL) {
                if (asid->rdi->type == ASIdentifierChoice_inherit)
                        return 1;
        }

        return 0;
}
LCRYPTO_ALIAS(X509v3_asid_inherits);

/*
 * Figure out whether parent contains child.
 */
static int
asid_contains(ASIdOrRanges *parent, ASIdOrRanges *child)
{
        ASN1_INTEGER *p_min = NULL, *p_max = NULL, *c_min = NULL, *c_max = NULL;
        int p, c;

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

        if (parent == NULL)
                return 0;

        p = 0;
        for (c = 0; c < sk_ASIdOrRange_num(child); c++) {
                if (!extract_min_max(sk_ASIdOrRange_value(child, c), &c_min,
                    &c_max))
                        return 0;
                for (;; p++) {
                        if (p >= sk_ASIdOrRange_num(parent))
                                return 0;
                        if (!extract_min_max(sk_ASIdOrRange_value(parent, p),
                            &p_min, &p_max))
                                return 0;
                        if (ASN1_INTEGER_cmp(p_max, c_max) < 0)
                                continue;
                        if (ASN1_INTEGER_cmp(p_min, c_min) > 0)
                                return 0;
                        break;
                }
        }

        return 1;
}

/*
 * Test whether child is a subset of parent.
 */
int
X509v3_asid_subset(ASIdentifiers *child, ASIdentifiers *parent)
{
        if (child == NULL || child == parent)
                return 1;

        if (parent == NULL)
                return 0;

        if (X509v3_asid_inherits(child) || X509v3_asid_inherits(parent))
                return 0;

        if (child->asnum != NULL) {
                if (parent->asnum == NULL)
                        return 0;

                if (!asid_contains(parent->asnum->u.asIdsOrRanges,
                    child->asnum->u.asIdsOrRanges))
                        return 0;
        }

        if (child->rdi != NULL) {
                if (parent->rdi == NULL)
                        return 0;

                if (!asid_contains(parent->rdi->u.asIdsOrRanges,
                    child->rdi->u.asIdsOrRanges))
                        return 0;
        }

        return 1;
}
LCRYPTO_ALIAS(X509v3_asid_subset);

/*
 * 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 3.3 path validation.
 */
static int
asid_validate_path_internal(X509_STORE_CTX *ctx, STACK_OF(X509) *chain,
    ASIdentifiers *ext)
{
        ASIdOrRanges *child_as = NULL, *child_rdi = NULL;
        int i, ret = 1, inherit_as = 0, inherit_rdi = 0;
        X509 *x;

        /* 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) {
                i = -1;
                x = NULL;
                if (!X509v3_asid_is_canonical(ext))
                        validation_err(X509_V_ERR_INVALID_EXTENSION);
        } else {
                i = 0;
                x = sk_X509_value(chain, i);
                if ((X509_get_extension_flags(x) & EXFLAG_INVALID) != 0)
                        goto done;
                if ((ext = x->rfc3779_asid) == NULL)
                        goto done;
        }
        if (ext->asnum != NULL) {
                switch (ext->asnum->type) {
                case ASIdentifierChoice_inherit:
                        inherit_as = 1;
                        break;
                case ASIdentifierChoice_asIdsOrRanges:
                        child_as = ext->asnum->u.asIdsOrRanges;
                        break;
                }
        }
        if (ext->rdi != NULL) {
                switch (ext->rdi->type) {
                case ASIdentifierChoice_inherit:
                        inherit_rdi = 1;
                        break;
                case ASIdentifierChoice_asIdsOrRanges:
                        child_rdi = ext->rdi->u.asIdsOrRanges;
                        break;
                }
        }

        /*
         * Now walk up the chain.  Extensions must be in canonical form, 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 ((X509_get_extension_flags(x) & EXFLAG_INVALID) != 0)
                        validation_err(X509_V_ERR_INVALID_EXTENSION);
                if (x->rfc3779_asid == NULL) {
                        if (child_as != NULL || child_rdi != NULL)
                                validation_err(X509_V_ERR_UNNESTED_RESOURCE);
                        continue;
                }
                if (x->rfc3779_asid->asnum == NULL && child_as != NULL) {
                        validation_err(X509_V_ERR_UNNESTED_RESOURCE);
                        child_as = NULL;
                        inherit_as = 0;
                }
                if (x->rfc3779_asid->asnum != NULL &&
                    x->rfc3779_asid->asnum->type ==
                    ASIdentifierChoice_asIdsOrRanges) {
                        if (inherit_as ||
                            asid_contains(x->rfc3779_asid->asnum->u.asIdsOrRanges,
                            child_as)) {
                                child_as = x->rfc3779_asid->asnum->u.asIdsOrRanges;
                                inherit_as = 0;
                        } else {
                                validation_err(X509_V_ERR_UNNESTED_RESOURCE);
                        }
                }
                if (x->rfc3779_asid->rdi == NULL && child_rdi != NULL) {
                        validation_err(X509_V_ERR_UNNESTED_RESOURCE);
                        child_rdi = NULL;
                        inherit_rdi = 0;
                }
                if (x->rfc3779_asid->rdi != NULL &&
                    x->rfc3779_asid->rdi->type == ASIdentifierChoice_asIdsOrRanges) {
                        if (inherit_rdi ||
                            asid_contains(x->rfc3779_asid->rdi->u.asIdsOrRanges,
                            child_rdi)) {
                                child_rdi = x->rfc3779_asid->rdi->u.asIdsOrRanges;
                                inherit_rdi = 0;
                        } else {
                                validation_err(X509_V_ERR_UNNESTED_RESOURCE);
                        }
                }
        }

        /*
         * Trust anchor can't inherit.
         */

        if (x == NULL)
                goto err;

        if (x->rfc3779_asid != NULL) {
                if (x->rfc3779_asid->asnum != NULL &&
                    x->rfc3779_asid->asnum->type == ASIdentifierChoice_inherit)
                        validation_err(X509_V_ERR_UNNESTED_RESOURCE);
                if (x->rfc3779_asid->rdi != NULL &&
                    x->rfc3779_asid->rdi->type == ASIdentifierChoice_inherit)
                        validation_err(X509_V_ERR_UNNESTED_RESOURCE);
        }

 done:
        return ret;

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

        return 0;
}

#undef validation_err

/*
 * RFC 3779 3.3 path validation -- called from X509_verify_cert().
 */
int
X509v3_asid_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 asid_validate_path_internal(ctx, ctx->chain, NULL);
}
LCRYPTO_ALIAS(X509v3_asid_validate_path);

/*
 * RFC 3779 3.3 path validation of an extension.
 * Test whether chain covers extension.
 */
int
X509v3_asid_validate_resource_set(STACK_OF(X509) *chain, ASIdentifiers *ext,
    int allow_inheritance)
{
        if (ext == NULL)
                return 1;
        if (sk_X509_num(chain) <= 0)
                return 0;
        if (!allow_inheritance && X509v3_asid_inherits(ext))
                return 0;
        return asid_validate_path_internal(NULL, chain, ext);
}
LCRYPTO_ALIAS(X509v3_asid_validate_resource_set);

#endif                          /* OPENSSL_NO_RFC3779 */