/* $OpenBSD: x509_lib.c,v 1.4 2022/07/24 21:41:29 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).
 *
 */
/* X509 v3 extension utilities */

#include <stdio.h>

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

#include "ext_dat.h"
#include "x509_lcl.h"

static STACK_OF(X509V3_EXT_METHOD) *ext_list = NULL;

static int ext_cmp(const X509V3_EXT_METHOD * const *a,
    const X509V3_EXT_METHOD * const *b);
static void ext_list_free(X509V3_EXT_METHOD *ext);

int
X509V3_EXT_add(X509V3_EXT_METHOD *ext)
{
        if (!ext_list && !(ext_list = sk_X509V3_EXT_METHOD_new(ext_cmp))) {
                X509V3error(ERR_R_MALLOC_FAILURE);
                return 0;
        }
        if (!sk_X509V3_EXT_METHOD_push(ext_list, ext)) {
                X509V3error(ERR_R_MALLOC_FAILURE);
                return 0;
        }
        return 1;
}

static int
ext_cmp(const X509V3_EXT_METHOD * const *a, const X509V3_EXT_METHOD * const *b)
{
        return ((*a)->ext_nid - (*b)->ext_nid);
}

static int ext_cmp_BSEARCH_CMP_FN(const void *, const void *);
static int ext_cmp(const X509V3_EXT_METHOD * const *, const X509V3_EXT_METHOD * const *);
static const X509V3_EXT_METHOD * *OBJ_bsearch_ext(const X509V3_EXT_METHOD * *key, const X509V3_EXT_METHOD * const *base, int num);

static int
ext_cmp_BSEARCH_CMP_FN(const void *a_, const void *b_)
{
        const X509V3_EXT_METHOD * const *a = a_;
        const X509V3_EXT_METHOD * const *b = b_;
        return ext_cmp(a, b);
}

static const X509V3_EXT_METHOD **
OBJ_bsearch_ext(const X509V3_EXT_METHOD **key,
    const X509V3_EXT_METHOD *const *base, int num)
{
        return (const X509V3_EXT_METHOD **)OBJ_bsearch_(key, base, num,
            sizeof(const X509V3_EXT_METHOD *), ext_cmp_BSEARCH_CMP_FN);
}

const X509V3_EXT_METHOD *
X509V3_EXT_get_nid(int nid)
{
        X509V3_EXT_METHOD tmp;
        const X509V3_EXT_METHOD *t = &tmp, * const *ret;
        int idx;

        if (nid < 0)
                return NULL;
        tmp.ext_nid = nid;
        ret = OBJ_bsearch_ext(&t, standard_exts, STANDARD_EXTENSION_COUNT);
        if (ret)
                return *ret;
        if (!ext_list)
                return NULL;
        idx = sk_X509V3_EXT_METHOD_find(ext_list, &tmp);
        if (idx == -1)
                return NULL;
        return sk_X509V3_EXT_METHOD_value(ext_list, idx);
}

const X509V3_EXT_METHOD *
X509V3_EXT_get(X509_EXTENSION *ext)
{
        int nid;

        if ((nid = OBJ_obj2nid(ext->object)) == NID_undef)
                return NULL;
        return X509V3_EXT_get_nid(nid);
}

int
X509V3_EXT_add_list(X509V3_EXT_METHOD *extlist)
{
        for (; extlist->ext_nid!=-1; extlist++)
                if (!X509V3_EXT_add(extlist))
                        return 0;
        return 1;
}

int
X509V3_EXT_add_alias(int nid_to, int nid_from)
{
        const X509V3_EXT_METHOD *ext;
        X509V3_EXT_METHOD *tmpext;

        if (!(ext = X509V3_EXT_get_nid(nid_from))) {
                X509V3error(X509V3_R_EXTENSION_NOT_FOUND);
                return 0;
        }
        if (!(tmpext = malloc(sizeof(X509V3_EXT_METHOD)))) {
                X509V3error(ERR_R_MALLOC_FAILURE);
                return 0;
        }
        *tmpext = *ext;
        tmpext->ext_nid = nid_to;
        tmpext->ext_flags |= X509V3_EXT_DYNAMIC;
        if (!X509V3_EXT_add(tmpext)) {
                free(tmpext);
                return 0;
        }
        return 1;
}

void
X509V3_EXT_cleanup(void)
{
        sk_X509V3_EXT_METHOD_pop_free(ext_list, ext_list_free);
        ext_list = NULL;
}

static void
ext_list_free(X509V3_EXT_METHOD *ext)
{
        if (ext->ext_flags & X509V3_EXT_DYNAMIC)
                free(ext);
}

/* Legacy function: we don't need to add standard extensions
 * any more because they are now kept in ext_dat.h.
 */

int
X509V3_add_standard_extensions(void)
{
        return 1;
}

/* Return an extension internal structure */

void *
X509V3_EXT_d2i(X509_EXTENSION *ext)
{
        const X509V3_EXT_METHOD *method;
        const unsigned char *p;

        if (!(method = X509V3_EXT_get(ext)))
                return NULL;
        p = ext->value->data;
        if (method->it)
                return ASN1_item_d2i(NULL, &p, ext->value->length,
                    method->it);
        return method->d2i(NULL, &p, ext->value->length);
}

/* Get critical flag and decoded version of extension from a NID.
 * The "idx" variable returns the last found extension and can
 * be used to retrieve multiple extensions of the same NID.
 * However multiple extensions with the same NID is usually
 * due to a badly encoded certificate so if idx is NULL we
 * choke if multiple extensions exist.
 * The "crit" variable is set to the critical value.
 * The return value is the decoded extension or NULL on
 * error. The actual error can have several different causes,
 * the value of *crit reflects the cause:
 * >= 0, extension found but not decoded (reflects critical value).
 * -1 extension not found.
 * -2 extension occurs more than once.
 */

void *
X509V3_get_d2i(const STACK_OF(X509_EXTENSION) *x, int nid, int *crit, int *idx)
{
        int lastpos, i;
        X509_EXTENSION *ex, *found_ex = NULL;

        if (!x) {
                if (idx)
                        *idx = -1;
                if (crit)
                        *crit = -1;
                return NULL;
        }
        if (idx)
                lastpos = *idx + 1;
        else
                lastpos = 0;
        if (lastpos < 0)
                lastpos = 0;
        for (i = lastpos; i < sk_X509_EXTENSION_num(x); i++) {
                ex = sk_X509_EXTENSION_value(x, i);
                if (OBJ_obj2nid(ex->object) == nid) {
                        if (idx) {
                                *idx = i;
                                found_ex = ex;
                                break;
                        } else if (found_ex) {
                                /* Found more than one */
                                if (crit)
                                        *crit = -2;
                                return NULL;
                        }
                        found_ex = ex;
                }
        }
        if (found_ex) {
                /* Found it */
                if (crit)
                        *crit = X509_EXTENSION_get_critical(found_ex);
                return X509V3_EXT_d2i(found_ex);
        }

        /* Extension not found */
        if (idx)
                *idx = -1;
        if (crit)
                *crit = -1;
        return NULL;
}

/* This function is a general extension append, replace and delete utility.
 * The precise operation is governed by the 'flags' value. The 'crit' and
 * 'value' arguments (if relevant) are the extensions internal structure.
 */

int
X509V3_add1_i2d(STACK_OF(X509_EXTENSION) **x, int nid, void *value,
    int crit, unsigned long flags)
{
        int extidx = -1;
        int errcode;
        X509_EXTENSION *ext, *extmp;
        unsigned long ext_op = flags & X509V3_ADD_OP_MASK;

        /* If appending we don't care if it exists, otherwise
         * look for existing extension.
         */
        if (ext_op != X509V3_ADD_APPEND)
                extidx = X509v3_get_ext_by_NID(*x, nid, -1);

        /* See if extension exists */
        if (extidx >= 0) {
                /* If keep existing, nothing to do */
                if (ext_op == X509V3_ADD_KEEP_EXISTING)
                        return 1;
                /* If default then its an error */
                if (ext_op == X509V3_ADD_DEFAULT) {
                        errcode = X509V3_R_EXTENSION_EXISTS;
                        goto err;
                }
                /* If delete, just delete it */
                if (ext_op == X509V3_ADD_DELETE) {
                        if ((extmp = sk_X509_EXTENSION_delete(*x, extidx)) == NULL)
                                return -1;
                        X509_EXTENSION_free(extmp);
                        return 1;
                }
        } else {
                /* If replace existing or delete, error since
                 * extension must exist
                 */
                if ((ext_op == X509V3_ADD_REPLACE_EXISTING) ||
                    (ext_op == X509V3_ADD_DELETE)) {
                        errcode = X509V3_R_EXTENSION_NOT_FOUND;
                        goto err;
                }
        }

        /* If we get this far then we have to create an extension:
         * could have some flags for alternative encoding schemes...
         */

        ext = X509V3_EXT_i2d(nid, crit, value);

        if (!ext) {
                X509V3error(X509V3_R_ERROR_CREATING_EXTENSION);
                return 0;
        }

        /* If extension exists replace it.. */
        if (extidx >= 0) {
                extmp = sk_X509_EXTENSION_value(*x, extidx);
                X509_EXTENSION_free(extmp);
                if (!sk_X509_EXTENSION_set(*x, extidx, ext))
                        return -1;
                return 1;
        }

        if (!*x && !(*x = sk_X509_EXTENSION_new_null()))
                return -1;
        if (!sk_X509_EXTENSION_push(*x, ext))
                return -1;

        return 1;

err:
        if (!(flags & X509V3_ADD_SILENT))
                X509V3error(errcode);
        return 0;
}