/*	$NetBSD: build_auth.c,v 1.3 2019/12/15 22:50:50 christos Exp $	*/

/*
 * Copyright (c) 1997 - 2003 Kungliga Tekniska Högskolan
 * (Royal Institute of Technology, Stockholm, Sweden).
 * 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. Neither the name of the Institute nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE 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 INSTITUTE 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 "krb5_locl.h"

static krb5_error_code
make_etypelist(krb5_context context,
	       krb5_authdata **auth_data)
{
    EtypeList etypes;
    krb5_error_code ret;
    krb5_authdata ad;
    u_char *buf;
    size_t len = 0;
    size_t buf_size;

    ret = _krb5_init_etype(context, KRB5_PDU_NONE,
			   &etypes.len, &etypes.val,
			   NULL);
    if (ret)
	return ret;

    ASN1_MALLOC_ENCODE(EtypeList, buf, buf_size, &etypes, &len, ret);
    if (ret) {
	free_EtypeList(&etypes);
	return ret;
    }
    if(buf_size != len)
	krb5_abortx(context, "internal error in ASN.1 encoder");
    free_EtypeList(&etypes);

    ALLOC_SEQ(&ad, 1);
    if (ad.val == NULL) {
	free(buf);
	return krb5_enomem(context);
    }

    ad.val[0].ad_type = KRB5_AUTHDATA_GSS_API_ETYPE_NEGOTIATION;
    ad.val[0].ad_data.length = len;
    ad.val[0].ad_data.data = buf;

    ASN1_MALLOC_ENCODE(AD_IF_RELEVANT, buf, buf_size, &ad, &len, ret);
    if (ret) {
	free_AuthorizationData(&ad);
	return ret;
    }
    if(buf_size != len)
	krb5_abortx(context, "internal error in ASN.1 encoder");
    free_AuthorizationData(&ad);

    ALLOC(*auth_data, 1);
    if (*auth_data == NULL) {
        free(buf);
	return krb5_enomem(context);
    }

    ALLOC_SEQ(*auth_data, 1);
    if ((*auth_data)->val == NULL) {
        free(*auth_data);
	free(buf);
	return krb5_enomem(context);
    }

    (*auth_data)->val[0].ad_type = KRB5_AUTHDATA_IF_RELEVANT;
    (*auth_data)->val[0].ad_data.length = len;
    (*auth_data)->val[0].ad_data.data = buf;

    return 0;
}

KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
_krb5_build_authenticator (krb5_context context,
			   krb5_auth_context auth_context,
			   krb5_enctype enctype,
			   krb5_creds *cred,
			   Checksum *cksum,
			   krb5_data *result,
			   krb5_key_usage usage)
{
    Authenticator auth;
    u_char *buf = NULL;
    size_t buf_size;
    size_t len = 0;
    krb5_error_code ret;
    krb5_crypto crypto;

    memset(&auth, 0, sizeof(auth));

    auth.authenticator_vno = 5;
    ret = copy_Realm(&cred->client->realm, &auth.crealm);
    if (ret)
	goto fail;
    ret = copy_PrincipalName(&cred->client->name, &auth.cname);
    if (ret)
	goto fail;

    krb5_us_timeofday (context, &auth.ctime, &auth.cusec);

    ret = krb5_auth_con_getlocalsubkey(context, auth_context, &auth.subkey);
    if(ret)
	goto fail;

    if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_SEQUENCE) {
	if(auth_context->local_seqnumber == 0)
	    krb5_generate_seq_number (context,
				      &cred->session,
				      &auth_context->local_seqnumber);
	ALLOC(auth.seq_number, 1);
	if(auth.seq_number == NULL) {
	    ret = krb5_enomem(context);
	    goto fail;
	}
	*auth.seq_number = auth_context->local_seqnumber;
    } else
	auth.seq_number = NULL;
    auth.authorization_data = NULL;

    if (cksum) {
	ALLOC(auth.cksum, 1);
	if (auth.cksum == NULL) {
	    ret = krb5_enomem(context);
	    goto fail;
	}
	ret = copy_Checksum(cksum, auth.cksum);
	if (ret)
	    goto fail;

	if (auth.cksum->cksumtype == CKSUMTYPE_GSSAPI) {
	    /*
	     * This is not GSS-API specific, we only enable it for
	     * GSS for now
	     */
	    ret = make_etypelist(context, &auth.authorization_data);
	    if (ret)
		goto fail;
	}
    }

    /* XXX - Copy more to auth_context? */

    auth_context->authenticator->ctime = auth.ctime;
    auth_context->authenticator->cusec = auth.cusec;

    ASN1_MALLOC_ENCODE(Authenticator, buf, buf_size, &auth, &len, ret);
    if (ret)
	goto fail;
    if(buf_size != len)
	krb5_abortx(context, "internal error in ASN.1 encoder");

    ret = krb5_crypto_init(context, &cred->session, enctype, &crypto);
    if (ret)
	goto fail;
    ret = krb5_encrypt (context,
			crypto,
			usage /* KRB5_KU_AP_REQ_AUTH */,
			buf,
			len,
			result);
    krb5_crypto_destroy(context, crypto);

    if (ret)
	goto fail;

 fail:
    free_Authenticator (&auth);
    free (buf);

    return ret;
}