/*

 * Copyright 2004-2023 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

 */

#include "internal/cryptlib.h"

#include <openssl/trace.h>

#include <openssl/x509.h>

#include <openssl/x509v3.h>

#include "pcy_local.h"

/*

 * If the maximum number of nodes in the policy tree isn't defined, set it to

 * a generous default of 1000 nodes.

 *

 * Defining this to be zero means unlimited policy tree growth which opens the

 * door on CVE-2023-0464.

 */

#ifndef OPENSSL_POLICY_TREE_NODES_MAX

#define OPENSSL_POLICY_TREE_NODES_MAX 1000

#endif

static void exnode_free(X509_POLICY_NODE *node);

static void expected_print(BIO *channel,

    X509_POLICY_LEVEL *lev, X509_POLICY_NODE *node,

    int indent)

{

    if ((lev->flags & X509_V_FLAG_INHIBIT_MAP)

        || !(node->data->flags & POLICY_DATA_FLAG_MAP_MASK))

        BIO_puts(channel, "  Not Mapped\n");

    else {

        int i;

        STACK_OF(ASN1_OBJECT) *pset = node->data->expected_policy_set;

        ASN1_OBJECT *oid;

        BIO_puts(channel, "  Expected: ");

        for (i = 0; i < sk_ASN1_OBJECT_num(pset); i++) {

            oid = sk_ASN1_OBJECT_value(pset, i);

            if (i)

                BIO_puts(channel, ", ");

            i2a_ASN1_OBJECT(channel, oid);

        }

        BIO_puts(channel, "\n");

    }

}

static void tree_print(BIO *channel,

    char *str, X509_POLICY_TREE *tree,

    X509_POLICY_LEVEL *curr)

{

    X509_POLICY_LEVEL *plev;

    if (!curr)

        curr = tree->levels + tree->nlevel;

    else

        curr++;

    BIO_printf(channel, "Level print after %s\n", str);

    BIO_printf(channel, "Printing Up to Level %ld\n",

        (long)(curr - tree->levels));

    for (plev = tree->levels; plev != curr; plev++) {

        int i;

        BIO_printf(channel, "Level %ld, flags = %x\n",

            (long)(plev - tree->levels), plev->flags);

        for (i = 0; i < sk_X509_POLICY_NODE_num(plev->nodes); i++) {

            X509_POLICY_NODE *node = sk_X509_POLICY_NODE_value(plev->nodes, i);

            X509_POLICY_NODE_print(channel, node, 2);

            expected_print(channel, plev, node, 2);

            BIO_printf(channel, "  Flags: %x\n", node->data->flags);

        }

        if (plev->anyPolicy)

            X509_POLICY_NODE_print(channel, plev->anyPolicy, 2);

    }

}

#define TREE_PRINT(str, tree, curr)                             \

    OSSL_TRACE_BEGIN(X509V3_POLICY)                             \

    {                                                           \

        tree_print(trc_out, "before tree_prune()", tree, curr); \

    }                                                           \

    OSSL_TRACE_END(X509V3_POLICY)

/*-

 * Return value: <= 0 on error, or positive bit mask:

 *

 * X509_PCY_TREE_VALID: valid tree

 * X509_PCY_TREE_EMPTY: empty tree (including bare TA case)

 * X509_PCY_TREE_EXPLICIT: explicit policy required

 */

static int tree_init(X509_POLICY_TREE **ptree, STACK_OF(X509) *certs,

    unsigned int flags)

{

    X509_POLICY_TREE *tree;

    X509_POLICY_LEVEL *level;

    const X509_POLICY_CACHE *cache;

    X509_POLICY_DATA *data = NULL;

    int ret = X509_PCY_TREE_VALID;

    int n = sk_X509_num(certs) - 1; /* RFC5280 paths omit the TA */

    int explicit_policy = (flags & X509_V_FLAG_EXPLICIT_POLICY) ? 0 : n + 1;

    int any_skip = (flags & X509_V_FLAG_INHIBIT_ANY) ? 0 : n + 1;

    int map_skip = (flags & X509_V_FLAG_INHIBIT_MAP) ? 0 : n + 1;

    int i;

    *ptree = NULL;

    /* Can't do anything with just a trust anchor */

    if (n == 0)

        return X509_PCY_TREE_EMPTY;

    /*

     * First setup the policy cache in all n non-TA certificates, this will be

     * used in X509_verify_cert() which will invoke the verify callback for all

     * certificates with invalid policy extensions.

     */

    for (i = n - 1; i >= 0; i--) {

        X509 *x = sk_X509_value(certs, i);

        /* Call for side-effect of computing hash and caching extensions */

        X509_check_purpose(x, -1, 0);

        /* If cache is NULL, likely ENOMEM: return immediately */

        if (ossl_policy_cache_set(x) == NULL)

            return X509_PCY_TREE_INTERNAL;

    }

    /*

     * At this point check for invalid policies and required explicit policy.

     * Note that the explicit_policy counter is a count-down to zero, with the

     * requirement kicking in if and once it does that.  The counter is

     * decremented for every non-self-issued certificate in the path, but may

     * be further reduced by policy constraints in a non-leaf certificate.

     *

     * The ultimate policy set is the intersection of all the policies along

     * the path, if we hit a certificate with an empty policy set, and explicit

     * policy is required we're done.

     */

    for (i = n - 1;

        i >= 0 && (explicit_policy > 0 || (ret & X509_PCY_TREE_EMPTY) == 0);

        i--) {

        X509 *x = sk_X509_value(certs, i);

        uint32_t ex_flags = X509_get_extension_flags(x);

        /* All the policies are already cached, we can return early */

        if (ex_flags & EXFLAG_INVALID_POLICY)

            return X509_PCY_TREE_INVALID;

        /* Access the cache which we now know exists */

        cache = ossl_policy_cache_set(x);

        if ((ret & X509_PCY_TREE_VALID) && cache->data == NULL)

            ret = X509_PCY_TREE_EMPTY;

        if (explicit_policy > 0) {

            if (!(ex_flags & EXFLAG_SI))

                explicit_policy--;

            if ((cache->explicit_skip >= 0)

                && (cache->explicit_skip < explicit_policy))

                explicit_policy = cache->explicit_skip;

        }

    }

    if (explicit_policy == 0)

        ret |= X509_PCY_TREE_EXPLICIT;

    if ((ret & X509_PCY_TREE_VALID) == 0)

        return ret;

    /* If we get this far initialize the tree */

    if ((tree = OPENSSL_zalloc(sizeof(*tree))) == NULL) {

        ERR_raise(ERR_LIB_X509V3, ERR_R_MALLOC_FAILURE);

        return X509_PCY_TREE_INTERNAL;

    }

    /* Limit the growth of the tree to mitigate CVE-2023-0464 */

    tree->node_maximum = OPENSSL_POLICY_TREE_NODES_MAX;

    /*

     * http://tools.ietf.org/html/rfc5280#section-6.1.2, figure 3.

     *

     * The top level is implicitly for the trust anchor with valid expected

     * policies of anyPolicy.  (RFC 5280 has the TA at depth 0 and the leaf at

     * depth n, we have the leaf at depth 0 and the TA at depth n).

     */

    if ((tree->levels = OPENSSL_zalloc(sizeof(*tree->levels) * (n + 1))) == NULL) {

        OPENSSL_free(tree);

        ERR_raise(ERR_LIB_X509V3, ERR_R_MALLOC_FAILURE);

        return X509_PCY_TREE_INTERNAL;

    }

    tree->nlevel = n + 1;

    level = tree->levels;

    if ((data = ossl_policy_data_new(NULL,

             OBJ_nid2obj(NID_any_policy), 0))

        == NULL)

        goto bad_tree;

    if (ossl_policy_level_add_node(level, data, NULL, tree, 1) == NULL) {

        ossl_policy_data_free(data);

        goto bad_tree;

    }

    /*

     * In this pass initialize all the tree levels and whether anyPolicy and

     * policy mapping are inhibited at each level.

     */

    for (i = n - 1; i >= 0; i--) {

        X509 *x = sk_X509_value(certs, i);

        uint32_t ex_flags = X509_get_extension_flags(x);

        /* Access the cache which we now know exists */

        cache = ossl_policy_cache_set(x);

        X509_up_ref(x);

        (++level)->cert = x;

        if (!cache->anyPolicy)

            level->flags |= X509_V_FLAG_INHIBIT_ANY;

        /* Determine inhibit any and inhibit map flags */

        if (any_skip == 0) {

            /*

             * Any matching allowed only if certificate is self issued and not

             * the last in the chain.

             */

            if (!(ex_flags & EXFLAG_SI) || (i == 0))

                level->flags |= X509_V_FLAG_INHIBIT_ANY;

        } else {

            if (!(ex_flags & EXFLAG_SI))

                any_skip--;

            if ((cache->any_skip >= 0) && (cache->any_skip < any_skip))

                any_skip = cache->any_skip;

        }

        if (map_skip == 0)

            level->flags |= X509_V_FLAG_INHIBIT_MAP;

        else {

            if (!(ex_flags & EXFLAG_SI))

                map_skip--;

            if ((cache->map_skip >= 0) && (cache->map_skip < map_skip))

                map_skip = cache->map_skip;

        }

    }

    *ptree = tree;

    return ret;

bad_tree:

    X509_policy_tree_free(tree);

    return X509_PCY_TREE_INTERNAL;

}

/*

 * Return value: 1 on success, 0 otherwise

 */

static int tree_link_matching_nodes(X509_POLICY_LEVEL *curr,

    X509_POLICY_DATA *data,

    X509_POLICY_TREE *tree)

{

    X509_POLICY_LEVEL *last = curr - 1;

    int i, matched = 0;

    /* Iterate through all in nodes linking matches */

    for (i = 0; i < sk_X509_POLICY_NODE_num(last->nodes); i++) {

        X509_POLICY_NODE *node = sk_X509_POLICY_NODE_value(last->nodes, i);

        if (ossl_policy_node_match(last, node, data->valid_policy)) {

            if (ossl_policy_level_add_node(curr, data, node, tree, 0) == NULL)

                return 0;

            matched = 1;

        }

    }

    if (!matched && last->anyPolicy) {

        if (ossl_policy_level_add_node(curr, data, last->anyPolicy, tree, 0) == NULL)

            return 0;

    }

    return 1;

}

/*

 * This corresponds to RFC3280 6.1.3(d)(1): link any data from

 * CertificatePolicies onto matching parent or anyPolicy if no match.

 *

 * Return value: 1 on success, 0 otherwise.

 */

static int tree_link_nodes(X509_POLICY_LEVEL *curr,

    const X509_POLICY_CACHE *cache,

    X509_POLICY_TREE *tree)

{

    int i;

    for (i = 0; i < sk_X509_POLICY_DATA_num(cache->data); i++) {

        X509_POLICY_DATA *data = sk_X509_POLICY_DATA_value(cache->data, i);

        /* Look for matching nodes in previous level */

        if (!tree_link_matching_nodes(curr, data, tree))

            return 0;

    }

    return 1;

}

/*

 * This corresponds to RFC3280 6.1.3(d)(2): Create new data for any unmatched

 * policies in the parent and link to anyPolicy.

 *

 * Return value: 1 on success, 0 otherwise.

 */

static int tree_add_unmatched(X509_POLICY_LEVEL *curr,

    const X509_POLICY_CACHE *cache,

    const ASN1_OBJECT *id,

    X509_POLICY_NODE *node, X509_POLICY_TREE *tree)

{

    X509_POLICY_DATA *data;

    if (id == NULL)

        id = node->data->valid_policy;

    /*

     * Create a new node with qualifiers from anyPolicy and id from unmatched

     * node.

     */

    if ((data = ossl_policy_data_new(NULL, id, node_critical(node))) == NULL)

        return 0;

    /* Curr may not have anyPolicy */

    data->qualifier_set = cache->anyPolicy->qualifier_set;

    data->flags |= POLICY_DATA_FLAG_SHARED_QUALIFIERS;

    if (ossl_policy_level_add_node(curr, data, node, tree, 1) == NULL) {

        ossl_policy_data_free(data);

        return 0;

    }

    return 1;

}

/*

 * Return value: 1 on success, 0 otherwise.

 */

static int tree_link_unmatched(X509_POLICY_LEVEL *curr,

    const X509_POLICY_CACHE *cache,

    X509_POLICY_NODE *node, X509_POLICY_TREE *tree)

{

    const X509_POLICY_LEVEL *last = curr - 1;

    int i;

    if ((last->flags & X509_V_FLAG_INHIBIT_MAP)

        || !(node->data->flags & POLICY_DATA_FLAG_MAPPED)) {

        /* If no policy mapping: matched if one child present */

        if (node->nchild)

            return 1;

        if (!tree_add_unmatched(curr, cache, NULL, node, tree))

            return 0;

        /* Add it */

    } else {

        /* If mapping: matched if one child per expected policy set */

        STACK_OF(ASN1_OBJECT) *expset = node->data->expected_policy_set;

        if (node->nchild == sk_ASN1_OBJECT_num(expset))

            return 1;

        /* Locate unmatched nodes */

        for (i = 0; i < sk_ASN1_OBJECT_num(expset); i++) {

            ASN1_OBJECT *oid = sk_ASN1_OBJECT_value(expset, i);

            if (ossl_policy_level_find_node(curr, node, oid))

                continue;

            if (!tree_add_unmatched(curr, cache, oid, node, tree))

                return 0;

        }

    }

    return 1;

}

/*

 * Return value: 1 on success, 0 otherwise

 */

static int tree_link_any(X509_POLICY_LEVEL *curr,

    const X509_POLICY_CACHE *cache,

    X509_POLICY_TREE *tree)

{

    int i;

    X509_POLICY_NODE *node;

    X509_POLICY_LEVEL *last = curr - 1;

    for (i = 0; i < sk_X509_POLICY_NODE_num(last->nodes); i++) {

        node = sk_X509_POLICY_NODE_value(last->nodes, i);

        if (!tree_link_unmatched(curr, cache, node, tree))

            return 0;

    }

    /* Finally add link to anyPolicy */

    if (last->anyPolicy && ossl_policy_level_add_node(curr, cache->anyPolicy, last->anyPolicy, tree, 0) == NULL)

        return 0;

    return 1;

}

/*-

 * Prune the tree: delete any child mapped child data on the current level then

 * proceed up the tree deleting any data with no children. If we ever have no

 * data on a level we can halt because the tree will be empty.

 *

 * Return value: <= 0 error, otherwise one of:

 *

 * X509_PCY_TREE_VALID: valid tree

 * X509_PCY_TREE_EMPTY: empty tree

 */

static int tree_prune(X509_POLICY_TREE *tree, X509_POLICY_LEVEL *curr)

{

    STACK_OF(X509_POLICY_NODE) *nodes;

    X509_POLICY_NODE *node;

    int i;

    nodes = curr->nodes;

    if (curr->flags & X509_V_FLAG_INHIBIT_MAP) {

        for (i = sk_X509_POLICY_NODE_num(nodes) - 1; i >= 0; i--) {

            node = sk_X509_POLICY_NODE_value(nodes, i);

            /* Delete any mapped data: see RFC3280 XXXX */

            if (node->data->flags & POLICY_DATA_FLAG_MAP_MASK) {

                node->parent->nchild--;

                OPENSSL_free(node);

                (void)sk_X509_POLICY_NODE_delete(nodes, i);

            }

        }

    }

    for (;;) {

        --curr;

        nodes = curr->nodes;

        for (i = sk_X509_POLICY_NODE_num(nodes) - 1; i >= 0; i--) {

            node = sk_X509_POLICY_NODE_value(nodes, i);

            if (node->nchild == 0) {

                node->parent->nchild--;

                OPENSSL_free(node);

                (void)sk_X509_POLICY_NODE_delete(nodes, i);

            }

        }

        if (curr->anyPolicy && !curr->anyPolicy->nchild) {

            if (curr->anyPolicy->parent)

                curr->anyPolicy->parent->nchild--;

            OPENSSL_free(curr->anyPolicy);

            curr->anyPolicy = NULL;

        }

        if (curr == tree->levels) {

            /* If we zapped anyPolicy at top then tree is empty */

            if (!curr->anyPolicy)

                return X509_PCY_TREE_EMPTY;

            break;

        }

    }

    return X509_PCY_TREE_VALID;

}

/*

 * Return value: 1 on success, 0 otherwise.

 */

static int tree_add_auth_node(STACK_OF(X509_POLICY_NODE) **pnodes,

    X509_POLICY_NODE *pcy)

{

    if (*pnodes == NULL && (*pnodes = ossl_policy_node_cmp_new()) == NULL)

        return 0;

    if (sk_X509_POLICY_NODE_find(*pnodes, pcy) >= 0)

        return 1;

    return sk_X509_POLICY_NODE_push(*pnodes, pcy) != 0;

}

#define TREE_CALC_FAILURE 0

#define TREE_CALC_OK_NOFREE 1

#define TREE_CALC_OK_DOFREE 2

/*-

 * Calculate the authority set based on policy tree. The 'pnodes' parameter is

 * used as a store for the set of policy nodes used to calculate the user set.

 * If the authority set is not anyPolicy then pnodes will just point to the

 * authority set. If however the authority set is anyPolicy then the set of

 * valid policies (other than anyPolicy) is store in pnodes.

 *

 * Return value:

 *  TREE_CALC_FAILURE on failure,

 *  TREE_CALC_OK_NOFREE on success and pnodes need not be freed,

 *  TREE_CALC_OK_DOFREE on success and pnodes needs to be freed

 */

static int tree_calculate_authority_set(X509_POLICY_TREE *tree,

    STACK_OF(X509_POLICY_NODE) **pnodes)

{

    X509_POLICY_LEVEL *curr;

    X509_POLICY_NODE *node, *anyptr;

    STACK_OF(X509_POLICY_NODE) **addnodes;

    int i, j;

    curr = tree->levels + tree->nlevel - 1;

    /* If last level contains anyPolicy set is anyPolicy */

    if (curr->anyPolicy) {

        if (!tree_add_auth_node(&tree->auth_policies, curr->anyPolicy))

            return TREE_CALC_FAILURE;

        addnodes = pnodes;

    } else

        /* Add policies to authority set */

        addnodes = &tree->auth_policies;

    curr = tree->levels;

    for (i = 1; i < tree->nlevel; i++) {

        /*

         * If no anyPolicy node on this level it can't appear on lower

         * levels so end search.

         */

        if ((anyptr = curr->anyPolicy) == NULL)

            break;

        curr++;

        for (j = 0; j < sk_X509_POLICY_NODE_num(curr->nodes); j++) {

            node = sk_X509_POLICY_NODE_value(curr->nodes, j);

            if ((node->parent == anyptr)

                && !tree_add_auth_node(addnodes, node)) {

                if (addnodes == pnodes) {

                    sk_X509_POLICY_NODE_free(*pnodes);

                    *pnodes = NULL;

                }

                return TREE_CALC_FAILURE;

            }

        }

    }

    if (addnodes == pnodes)

        return TREE_CALC_OK_DOFREE;

    *pnodes = tree->auth_policies;

    return TREE_CALC_OK_NOFREE;

}

/*

 * Return value: 1 on success, 0 otherwise.

 */

static int tree_calculate_user_set(X509_POLICY_TREE *tree,

    STACK_OF(ASN1_OBJECT) *policy_oids,

    STACK_OF(X509_POLICY_NODE) *auth_nodes)

{

    int i;

    X509_POLICY_NODE *node;

    ASN1_OBJECT *oid;

    X509_POLICY_NODE *anyPolicy;

    X509_POLICY_DATA *extra;

    /*

     * Check if anyPolicy present in authority constrained policy set: this

     * will happen if it is a leaf node.

     */

    if (sk_ASN1_OBJECT_num(policy_oids) <= 0)

        return 1;

    anyPolicy = tree->levels[tree->nlevel - 1].anyPolicy;

    for (i = 0; i < sk_ASN1_OBJECT_num(policy_oids); i++) {

        oid = sk_ASN1_OBJECT_value(policy_oids, i);

        if (OBJ_obj2nid(oid) == NID_any_policy) {

            tree->flags |= POLICY_FLAG_ANY_POLICY;

            return 1;

        }

    }

    for (i = 0; i < sk_ASN1_OBJECT_num(policy_oids); i++) {

        oid = sk_ASN1_OBJECT_value(policy_oids, i);

        node = ossl_policy_tree_find_sk(auth_nodes, oid);

        if (!node) {

            if (!anyPolicy)

                continue;

            /*

             * Create a new node with policy ID from user set and qualifiers

             * from anyPolicy.

             */

            extra = ossl_policy_data_new(NULL, oid, node_critical(anyPolicy));

            if (extra == NULL)

                return 0;

            extra->qualifier_set = anyPolicy->data->qualifier_set;

            extra->flags = POLICY_DATA_FLAG_SHARED_QUALIFIERS

                | POLICY_DATA_FLAG_EXTRA_NODE;

            node = ossl_policy_level_add_node(NULL, extra, anyPolicy->parent,

                tree, 1);

            if (node == NULL) {

                ossl_policy_data_free(extra);

                return 0;

            }

        }

        if (!tree->user_policies) {

            tree->user_policies = sk_X509_POLICY_NODE_new_null();

            if (!tree->user_policies) {

                exnode_free(node);

                return 0;

            }

        }

        if (!sk_X509_POLICY_NODE_push(tree->user_policies, node)) {

            exnode_free(node);

            return 0;

        }

    }

    return 1;

}

/*-

 * Return value: <= 0 error, otherwise one of:

 *  X509_PCY_TREE_VALID: valid tree

 *  X509_PCY_TREE_EMPTY: empty tree

 * (see tree_prune()).

 */

static int tree_evaluate(X509_POLICY_TREE *tree)

{

    int ret, i;

    X509_POLICY_LEVEL *curr = tree->levels + 1;

    const X509_POLICY_CACHE *cache;

    for (i = 1; i < tree->nlevel; i++, curr++) {

        cache = ossl_policy_cache_set(curr->cert);

        if (!tree_link_nodes(curr, cache, tree))

            return X509_PCY_TREE_INTERNAL;

        if (!(curr->flags & X509_V_FLAG_INHIBIT_ANY)

            && !tree_link_any(curr, cache, tree))

            return X509_PCY_TREE_INTERNAL;

        TREE_PRINT("before tree_prune()", tree, curr);

        ret = tree_prune(tree, curr);

        if (ret != X509_PCY_TREE_VALID)

            return ret;

    }

    return X509_PCY_TREE_VALID;

}

static void exnode_free(X509_POLICY_NODE *node)

{

    if (node->data && (node->data->flags & POLICY_DATA_FLAG_EXTRA_NODE))

        OPENSSL_free(node);

}

void X509_policy_tree_free(X509_POLICY_TREE *tree)

{

    X509_POLICY_LEVEL *curr;

    int i;

    if (!tree)

        return;

    sk_X509_POLICY_NODE_free(tree->auth_policies);

    sk_X509_POLICY_NODE_pop_free(tree->user_policies, exnode_free);

    for (i = 0, curr = tree->levels; i < tree->nlevel; i++, curr++) {

        X509_free(curr->cert);

        sk_X509_POLICY_NODE_pop_free(curr->nodes, ossl_policy_node_free);

        ossl_policy_node_free(curr->anyPolicy);

    }

    sk_X509_POLICY_DATA_pop_free(tree->extra_data, ossl_policy_data_free);

    OPENSSL_free(tree->levels);

    OPENSSL_free(tree);

}

/*-

 * Application policy checking function.

 * Return codes:

 *  X509_PCY_TREE_FAILURE:  Failure to satisfy explicit policy

 *  X509_PCY_TREE_INVALID:  Inconsistent or invalid extensions

 *  X509_PCY_TREE_INTERNAL: Internal error, most likely malloc

 *  X509_PCY_TREE_VALID:    Success (null tree if empty or bare TA)

 */

int X509_policy_check(X509_POLICY_TREE **ptree, int *pexplicit_policy,

    STACK_OF(X509) *certs,

    STACK_OF(ASN1_OBJECT) *policy_oids, unsigned int flags)

{

    int init_ret;

    int ret;

    int calc_ret;

    X509_POLICY_TREE *tree = NULL;

    STACK_OF(X509_POLICY_NODE) *nodes, *auth_nodes = NULL;

    *ptree = NULL;

    *pexplicit_policy = 0;

    init_ret = tree_init(&tree, certs, flags);

    if (init_ret <= 0)

        return init_ret;

    if ((init_ret & X509_PCY_TREE_EXPLICIT) == 0) {

        if (init_ret & X509_PCY_TREE_EMPTY) {

            X509_policy_tree_free(tree);

            return X509_PCY_TREE_VALID;

        }

    } else {

        *pexplicit_policy = 1;

        /* Tree empty and requireExplicit True: Error */

        if (init_ret & X509_PCY_TREE_EMPTY)

            return X509_PCY_TREE_FAILURE;

    }

    ret = tree_evaluate(tree);

    TREE_PRINT("tree_evaluate()", tree, NULL);

    if (ret <= 0)

        goto error;

    if (ret == X509_PCY_TREE_EMPTY) {

        X509_policy_tree_free(tree);

        if (init_ret & X509_PCY_TREE_EXPLICIT)

            return X509_PCY_TREE_FAILURE;

        return X509_PCY_TREE_VALID;

    }

    /* Tree is not empty: continue */

    if ((calc_ret = tree_calculate_authority_set(tree, &auth_nodes)) == 0)

        goto error;

    ret = tree_calculate_user_set(tree, policy_oids, auth_nodes);

    if (calc_ret == TREE_CALC_OK_DOFREE)

        sk_X509_POLICY_NODE_free(auth_nodes);

    if (!ret)

        goto error;

    *ptree = tree;

    if (init_ret & X509_PCY_TREE_EXPLICIT) {

        nodes = X509_policy_tree_get0_user_policies(tree);

        if (sk_X509_POLICY_NODE_num(nodes) <= 0)

            return X509_PCY_TREE_FAILURE;

    }

    return X509_PCY_TREE_VALID;

error:

    X509_policy_tree_free(tree);

    return X509_PCY_TREE_INTERNAL;

}