/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2005 Doug Rabson
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS 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 AUTHOR OR 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.
 */

#include <gssapi/gssapi.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>

#include "mech_switch.h"
#include "utils.h"
#include "name.h"

static OM_uint32
_gss_import_export_name(OM_uint32 *minor_status,
    const gss_buffer_t input_name_buffer,
    gss_name_t *output_name)
{
        OM_uint32 major_status;
        unsigned char *p = input_name_buffer->value;
        size_t len = input_name_buffer->length;
        size_t t;
        gss_OID_desc mech_oid;
        struct _gss_mech_switch *m;
        struct _gss_name *name;
        gss_name_t new_canonical_name;

        *minor_status = 0;
        *output_name = 0;

        /*
         * Make sure that TOK_ID is {4, 1}.
         */
        if (len < 2)
                return (GSS_S_BAD_NAME);
        if (p[0] != 4 || p[1] != 1)
                return (GSS_S_BAD_NAME);
        p += 2;
        len -= 2;

        /*
         * Get the mech length and the name length and sanity
         * check the size of of the buffer.
         */
        if (len < 2)
                return (GSS_S_BAD_NAME);
        t = (p[0] << 8) + p[1];
        p += 2;
        len -= 2;

        /*
         * Check the DER encoded OID to make sure it agrees with the
         * length we just decoded.
         */
        if (p[0] != 6)          /* 6=OID */
                return (GSS_S_BAD_NAME);
        p++;
        len--;
        t--;
        if (p[0] & 0x80) {
                int digits = p[0];
                p++;
                len--;
                t--;
                mech_oid.length = 0;
                while (digits--) {
                        mech_oid.length = (mech_oid.length << 8) | p[0];
                        p++;
                        len--;
                        t--;
                }
        } else {
                mech_oid.length = p[0];
                p++;
                len--;
                t--;
        }
        if (mech_oid.length != t)
                return (GSS_S_BAD_NAME);

        mech_oid.elements = p;

        if (len < t + 4)
                return (GSS_S_BAD_NAME);
        p += t;
        len -= t;

        t = (p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3];
        p += 4;
        len -= 4;

        if (len != t)
                return (GSS_S_BAD_NAME);

        m = _gss_find_mech_switch(&mech_oid);
        if (!m)
                return (GSS_S_BAD_MECH);

        /*
         * Ask the mechanism to import the name.
         */
        major_status = m->gm_import_name(minor_status,
            input_name_buffer, GSS_C_NT_EXPORT_NAME, &new_canonical_name);
        if (major_status != GSS_S_COMPLETE) {
                _gss_mg_error(m, major_status, *minor_status);
                return (major_status);
        }

        /*
         * Now we make a new name and mark it as an MN.
         */
        name = _gss_make_name(m, new_canonical_name);
        if (!name) {
                m->gm_release_name(minor_status, &new_canonical_name);
                return (GSS_S_FAILURE);
        }

        *output_name = (gss_name_t) name;

        *minor_status = 0;
        return (GSS_S_COMPLETE);
}

OM_uint32
gss_import_name(OM_uint32 *minor_status,
    const gss_buffer_t input_name_buffer,
    const gss_OID input_name_type,
    gss_name_t *output_name)
{
        gss_OID                 name_type = input_name_type;
        OM_uint32               major_status;
        struct _gss_name        *name;

        *output_name = GSS_C_NO_NAME;

        if (input_name_buffer->length == 0) {
                *minor_status = 0;
                return (GSS_S_BAD_NAME);
        }

        /*
         * Use GSS_NT_USER_NAME as default name type.
         */
        if (name_type == GSS_C_NO_OID)
                name_type = GSS_C_NT_USER_NAME;

        /*
         * If this is an exported name, we need to parse it to find
         * the mechanism and then import it as an MN. See RFC 2743
         * section 3.2 for a description of the format.
         */
        if (gss_oid_equal(name_type, GSS_C_NT_EXPORT_NAME)) {
                return _gss_import_export_name(minor_status,
                    input_name_buffer, output_name);
        }

        /*
         * Only allow certain name types. This is pretty bogus - we
         * should figure out the list of supported name types using
         * gss_inquire_names_for_mech.
         */
        if (!gss_oid_equal(name_type, GSS_C_NT_USER_NAME)
            && !gss_oid_equal(name_type, GSS_C_NT_MACHINE_UID_NAME)
            && !gss_oid_equal(name_type, GSS_C_NT_STRING_UID_NAME)
            && !gss_oid_equal(name_type, GSS_C_NT_HOSTBASED_SERVICE_X)
            && !gss_oid_equal(name_type, GSS_C_NT_HOSTBASED_SERVICE)
            && !gss_oid_equal(name_type, GSS_C_NT_ANONYMOUS)
            && !gss_oid_equal(name_type, GSS_KRB5_NT_PRINCIPAL_NAME)) {
                *minor_status = 0;
                return (GSS_S_BAD_NAMETYPE);
        }

        *minor_status = 0;
        name = malloc(sizeof(struct _gss_name));
        if (!name) {
                *minor_status = ENOMEM;
                return (GSS_S_FAILURE);
        }
        memset(name, 0, sizeof(struct _gss_name));

        major_status = _gss_copy_oid(minor_status,
            name_type, &name->gn_type);
        if (major_status) {
                free(name);
                return (GSS_S_FAILURE);
        }

        major_status = _gss_copy_buffer(minor_status,
            input_name_buffer, &name->gn_value);
        if (major_status) {
                gss_name_t rname = (gss_name_t)name;
                gss_release_name(minor_status, &rname);
                return (GSS_S_FAILURE);
        }

        SLIST_INIT(&name->gn_mn);

        *output_name = (gss_name_t) name;
        return (GSS_S_COMPLETE);
}