/* $OpenBSD: x509_trs.c,v 1.25 2021/11/01 20:53:08 tb Exp $ */
/* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
 * project 1999.
 */
/* ====================================================================
 * Copyright (c) 1999 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).
 *
 */

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

#include <openssl/err.h>
#include <openssl/x509v3.h>

#include "x509_lcl.h"

static int tr_cmp(const X509_TRUST * const *a, const X509_TRUST * const *b);
static void trtable_free(X509_TRUST *p);

static int trust_1oidany(X509_TRUST *trust, X509 *x, int flags);
static int trust_1oid(X509_TRUST *trust, X509 *x, int flags);
static int trust_compat(X509_TRUST *trust, X509 *x, int flags);

static int obj_trust(int id, X509 *x, int flags);
static int (*default_trust)(int id, X509 *x, int flags) = obj_trust;

/* WARNING: the following table should be kept in order of trust
 * and without any gaps so we can just subtract the minimum trust
 * value to get an index into the table
 */

static X509_TRUST trstandard[] = {
        {X509_TRUST_COMPAT, 0, trust_compat, "compatible", 0, NULL},
        {X509_TRUST_SSL_CLIENT, 0, trust_1oidany, "SSL Client", NID_client_auth, NULL},
        {X509_TRUST_SSL_SERVER, 0, trust_1oidany, "SSL Server", NID_server_auth, NULL},
        {X509_TRUST_EMAIL, 0, trust_1oidany, "S/MIME email", NID_email_protect, NULL},
        {X509_TRUST_OBJECT_SIGN, 0, trust_1oidany, "Object Signer", NID_code_sign, NULL},
        {X509_TRUST_OCSP_SIGN, 0, trust_1oid, "OCSP responder", NID_OCSP_sign, NULL},
        {X509_TRUST_OCSP_REQUEST, 0, trust_1oid, "OCSP request", NID_ad_OCSP, NULL},
        {X509_TRUST_TSA, 0, trust_1oidany, "TSA server", NID_time_stamp, NULL}
};

#define X509_TRUST_COUNT        (sizeof(trstandard)/sizeof(X509_TRUST))

static STACK_OF(X509_TRUST) *trtable = NULL;

static int
tr_cmp(const X509_TRUST * const *a, const X509_TRUST * const *b)
{
        return (*a)->trust - (*b)->trust;
}

int
(*X509_TRUST_set_default(int (*trust)(int , X509 *, int)))(int, X509 *, int)
{
        int (*oldtrust)(int , X509 *, int);

        oldtrust = default_trust;
        default_trust = trust;
        return oldtrust;
}

int
X509_check_trust(X509 *x, int id, int flags)
{
        X509_TRUST *pt;
        int idx;

        if (id == -1)
                return 1;
        /*
         * XXX beck/jsing This enables self signed certs to be trusted for
         * an unspecified id/trust flag value (this is NOT the
         * X509_TRUST_DEFAULT), which was the longstanding
         * openssl behaviour. boringssl does not have this behaviour.
         *
         * This should be revisited, but changing the default "not default"
         * may break things.
         */
        if (id == 0) {
                int rv;
                rv = obj_trust(NID_anyExtendedKeyUsage, x, 0);
                if (rv != X509_TRUST_UNTRUSTED)
                        return rv;
                return trust_compat(NULL, x, 0);
        }
        idx = X509_TRUST_get_by_id(id);
        if (idx == -1)
                return default_trust(id, x, flags);
        pt = X509_TRUST_get0(idx);
        return pt->check_trust(pt, x, flags);
}

int
X509_TRUST_get_count(void)
{
        if (!trtable)
                return X509_TRUST_COUNT;
        return sk_X509_TRUST_num(trtable) + X509_TRUST_COUNT;
}

X509_TRUST *
X509_TRUST_get0(int idx)
{
        if (idx < 0)
                return NULL;
        if (idx < (int)X509_TRUST_COUNT)
                return trstandard + idx;
        return sk_X509_TRUST_value(trtable, idx - X509_TRUST_COUNT);
}

int
X509_TRUST_get_by_id(int id)
{
        X509_TRUST tmp;
        int idx;

        if ((id >= X509_TRUST_MIN) && (id <= X509_TRUST_MAX))
                return id - X509_TRUST_MIN;
        tmp.trust = id;
        if (!trtable)
                return -1;
        idx = sk_X509_TRUST_find(trtable, &tmp);
        if (idx == -1)
                return -1;
        return idx + X509_TRUST_COUNT;
}

int
X509_TRUST_set(int *t, int trust)
{
        if (X509_TRUST_get_by_id(trust) == -1) {
                X509error(X509_R_INVALID_TRUST);
                return 0;
        }
        *t = trust;
        return 1;
}

int
X509_TRUST_add(int id, int flags, int (*ck)(X509_TRUST *, X509 *, int),
    const char *name, int arg1, void *arg2)
{
        int idx;
        X509_TRUST *trtmp;
        char *name_dup;

        /* This is set according to what we change: application can't set it */
        flags &= ~X509_TRUST_DYNAMIC;
        /* This will always be set for application modified trust entries */
        flags |= X509_TRUST_DYNAMIC_NAME;
        /* Get existing entry if any */
        idx = X509_TRUST_get_by_id(id);
        /* Need a new entry */
        if (idx == -1) {
                if (!(trtmp = malloc(sizeof(X509_TRUST)))) {
                        X509error(ERR_R_MALLOC_FAILURE);
                        return 0;
                }
                trtmp->flags = X509_TRUST_DYNAMIC;
        } else {
                trtmp = X509_TRUST_get0(idx);
                if (trtmp == NULL) {
                        X509error(X509_R_INVALID_TRUST);
                        return 0;
                }
        }

        if ((name_dup = strdup(name)) == NULL)
                goto err;

        /* free existing name if dynamic */
        if (trtmp->flags & X509_TRUST_DYNAMIC_NAME)
                free(trtmp->name);
        /* dup supplied name */
        trtmp->name = name_dup;
        /* Keep the dynamic flag of existing entry */
        trtmp->flags &= X509_TRUST_DYNAMIC;
        /* Set all other flags */
        trtmp->flags |= flags;

        trtmp->trust = id;
        trtmp->check_trust = ck;
        trtmp->arg1 = arg1;
        trtmp->arg2 = arg2;

        /* If it's a new entry, manage the dynamic table */
        if (idx == -1) {
                if (trtable == NULL &&
                    (trtable = sk_X509_TRUST_new(tr_cmp)) == NULL)
                        goto err;
                if (sk_X509_TRUST_push(trtable, trtmp) == 0)
                        goto err;
        }
        return 1;

err:
        free(name_dup);
        if (idx == -1)
                free(trtmp);
        X509error(ERR_R_MALLOC_FAILURE);
        return 0;
}

static void
trtable_free(X509_TRUST *p)
{
        if (!p)
                return;
        if (p->flags & X509_TRUST_DYNAMIC) {
                if (p->flags & X509_TRUST_DYNAMIC_NAME)
                        free(p->name);
                free(p);
        }
}

void
X509_TRUST_cleanup(void)
{
        sk_X509_TRUST_pop_free(trtable, trtable_free);
        trtable = NULL;
}

int
X509_TRUST_get_flags(const X509_TRUST *xp)
{
        return xp->flags;
}

char *
X509_TRUST_get0_name(const X509_TRUST *xp)
{
        return xp->name;
}

int
X509_TRUST_get_trust(const X509_TRUST *xp)
{
        return xp->trust;
}

static int
trust_1oidany(X509_TRUST *trust, X509 *x, int flags)
{
        if (x->aux && (x->aux->trust || x->aux->reject))
                return obj_trust(trust->arg1, x, flags);
        /* we don't have any trust settings: for compatibility
         * we return trusted if it is self signed
         */
        return trust_compat(trust, x, flags);
}

static int
trust_1oid(X509_TRUST *trust, X509 *x, int flags)
{
        if (x->aux)
                return obj_trust(trust->arg1, x, flags);
        return X509_TRUST_UNTRUSTED;
}

static int
trust_compat(X509_TRUST *trust, X509 *x, int flags)
{
        X509_check_purpose(x, -1, 0);
        if (x->ex_flags & EXFLAG_SS)
                return X509_TRUST_TRUSTED;
        else
                return X509_TRUST_UNTRUSTED;
}

static int
obj_trust(int id, X509 *x, int flags)
{
        ASN1_OBJECT *obj;
        int i;
        X509_CERT_AUX *ax;

        ax = x->aux;
        if (!ax)
                return X509_TRUST_UNTRUSTED;
        if (ax->reject) {
                for (i = 0; i < sk_ASN1_OBJECT_num(ax->reject); i++) {
                        obj = sk_ASN1_OBJECT_value(ax->reject, i);
                        if (OBJ_obj2nid(obj) == id)
                                return X509_TRUST_REJECTED;
                }
        }
        if (ax->trust) {
                for (i = 0; i < sk_ASN1_OBJECT_num(ax->trust); i++) {
                        obj = sk_ASN1_OBJECT_value(ax->trust, i);
                        if (OBJ_obj2nid(obj) == id)
                                return X509_TRUST_TRUSTED;
                }
        }
        return X509_TRUST_UNTRUSTED;
}