/*
 * 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>

RCSID("$Id: build_auth.c 17033 2006-04-10 08:53:21Z lha $");

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;
    size_t buf_size;
     
    ret = krb5_init_etype(context, &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);
	krb5_set_error_string(context, "malloc: out of memory");
	return ENOMEM;
    }

    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) {
	krb5_set_error_string(context, "malloc: out of memory");
	return ENOMEM;
    }

    ALLOC_SEQ(*auth_data, 1);
    if ((*auth_data)->val == NULL) {
	free(buf);
	krb5_set_error_string(context, "malloc: out of memory");
	return ENOMEM;
    }

    (*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_error_code KRB5_LIB_FUNCTION
krb5_build_authenticator (krb5_context context,
			  krb5_auth_context auth_context,
			  krb5_enctype enctype,
			  krb5_creds *cred,
			  Checksum *cksum,
			  Authenticator **auth_result,
			  krb5_data *result,
			  krb5_key_usage usage)
{
    Authenticator *auth;
    u_char *buf = NULL;
    size_t buf_size;
    size_t len;
    krb5_error_code ret;
    krb5_crypto crypto;

    auth = calloc(1, sizeof(*auth));
    if (auth == NULL) {
	krb5_set_error_string(context, "malloc: out of memory");
	return ENOMEM;
    }

    auth->authenticator_vno = 5;
    copy_Realm(&cred->client->realm, &auth->crealm);
    copy_PrincipalName(&cred->client->name, &auth->cname);

    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 = ENOMEM;
	    goto fail;
	}
	*auth->seq_number = auth_context->local_seqnumber;
    } else
	auth->seq_number = NULL;
    auth->authorization_data = NULL;
    auth->cksum = cksum;

    if (cksum != NULL && 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 + buf_size - len, 
			len,
			result);
    krb5_crypto_destroy(context, crypto);

    if (ret)
	goto fail;

    free (buf);

    if (auth_result)
	*auth_result = auth;
    else {
	/* Don't free the `cksum', it's allocated by the caller */
	auth->cksum = NULL;
	free_Authenticator (auth);
	free (auth);
    }
    return ret;
  fail:
    free_Authenticator (auth);
    free (auth);
    free (buf);
    return ret;
}