/*
 * Copyright (c) 1997 - 2002 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 "gssapi_locl.h"

RCSID("$Id: acquire_cred.c,v 1.10 2002/08/20 12:02:45 nectar Exp $");

static krb5_error_code
get_keytab(krb5_keytab *keytab)
{
    char kt_name[256];
    krb5_error_code kret;

    if (gssapi_krb5_keytab != NULL) {
	kret = krb5_kt_get_name(gssapi_krb5_context,
				gssapi_krb5_keytab,
				kt_name, sizeof(kt_name));
	if (kret == 0)
	    kret = krb5_kt_resolve(gssapi_krb5_context, kt_name, keytab);
    } else
	kret = krb5_kt_default(gssapi_krb5_context, keytab);
    return (kret);
}

static OM_uint32 acquire_initiator_cred
		  (OM_uint32 * minor_status,
		   const gss_name_t desired_name,
		   OM_uint32 time_req,
		   const gss_OID_set desired_mechs,
		   gss_cred_usage_t cred_usage,
		   gss_cred_id_t handle,
		   gss_OID_set * actual_mechs,
		   OM_uint32 * time_rec
		  )
{
    OM_uint32 ret;
    krb5_creds cred;
    krb5_principal def_princ;
    krb5_get_init_creds_opt opt;
    krb5_ccache ccache;
    krb5_keytab keytab;
    krb5_error_code kret;

    keytab = NULL;
    ccache = NULL;
    def_princ = NULL;
    ret = GSS_S_FAILURE;
    memset(&cred, 0, sizeof(cred));

    kret = krb5_cc_default(gssapi_krb5_context, &ccache);
    if (kret)
	goto end;
    kret = krb5_cc_get_principal(gssapi_krb5_context, ccache,
	&def_princ);
    if (kret != 0) {
	/* we'll try to use a keytab below */
	krb5_cc_destroy(gssapi_krb5_context, ccache);
	ccache = NULL;
	kret = 0;
    } else if (handle->principal == NULL)  {
	kret = krb5_copy_principal(gssapi_krb5_context, def_princ,
	    &handle->principal);
	if (kret)
	    goto end;
    } else if (handle->principal != NULL &&
	krb5_principal_compare(gssapi_krb5_context, handle->principal,
	def_princ) == FALSE) {
	kret = KRB5_PRINC_NOMATCH;
	goto end;
    }
    if (def_princ == NULL) {
	/* We have no existing credentials cache,
	 * so attempt to get a TGT using a keytab.
	 */
	if (handle->principal == NULL) {
	    kret = krb5_get_default_principal(gssapi_krb5_context,
		&handle->principal);
	    if (kret)
		goto end;
	}
	kret = get_keytab(&keytab);
	if (kret)
	    goto end;
	krb5_get_init_creds_opt_init(&opt);
	kret = krb5_get_init_creds_keytab(gssapi_krb5_context, &cred,
	    handle->principal, keytab, 0, NULL, &opt);
	if (kret)
	    goto end;
	kret = krb5_cc_gen_new(gssapi_krb5_context, &krb5_mcc_ops,
		&ccache);
	if (kret)
	    goto end;
	kret = krb5_cc_initialize(gssapi_krb5_context, ccache, cred.client);
	if (kret)
	    goto end;
	kret = krb5_cc_store_cred(gssapi_krb5_context, ccache, &cred);
	if (kret)
	    goto end;
    }
    handle->ccache = ccache;
    ret = GSS_S_COMPLETE;

end:
    if (cred.client != NULL)
	krb5_free_creds_contents(gssapi_krb5_context, &cred);
    if (def_princ != NULL)
	krb5_free_principal(gssapi_krb5_context, def_princ);
    if (keytab != NULL)
	krb5_kt_close(gssapi_krb5_context, keytab);
    if (ret != GSS_S_COMPLETE) {
	if (ccache != NULL)
	    krb5_cc_close(gssapi_krb5_context, ccache);
	if (kret != 0) {
	    *minor_status = kret;
	    gssapi_krb5_set_error_string ();
	}
    }
    return (ret);
}

static OM_uint32 acquire_acceptor_cred
		  (OM_uint32 * minor_status,
		   const gss_name_t desired_name,
		   OM_uint32 time_req,
		   const gss_OID_set desired_mechs,
		   gss_cred_usage_t cred_usage,
		   gss_cred_id_t handle,
		   gss_OID_set * actual_mechs,
		   OM_uint32 * time_rec
		  )
{
    OM_uint32 ret;
    krb5_error_code kret;

    kret = 0;
    ret = GSS_S_FAILURE;
    kret = get_keytab(&handle->keytab);
    if (kret)
	goto end;
    ret = GSS_S_COMPLETE;
 
end:
    if (ret != GSS_S_COMPLETE) {
	if (handle->keytab != NULL)
	    krb5_kt_close(gssapi_krb5_context, handle->keytab);
	if (kret != 0) {
	    *minor_status = kret;
	    gssapi_krb5_set_error_string ();
	}
    }
    return (ret);
}

OM_uint32 gss_acquire_cred
           (OM_uint32 * minor_status,
            const gss_name_t desired_name,
            OM_uint32 time_req,
            const gss_OID_set desired_mechs,
            gss_cred_usage_t cred_usage,
            gss_cred_id_t * output_cred_handle,
            gss_OID_set * actual_mechs,
            OM_uint32 * time_rec
           )
{
    gss_cred_id_t handle;
    OM_uint32 ret;

    gssapi_krb5_init ();

    *minor_status = 0;
    handle = (gss_cred_id_t)malloc(sizeof(*handle));
    if (handle == GSS_C_NO_CREDENTIAL)
        return (GSS_S_FAILURE);

    memset(handle, 0, sizeof (*handle));

    if (desired_name != GSS_C_NO_NAME) {
	ret = gss_duplicate_name(minor_status, desired_name,
	    &handle->principal);
	if (ret != GSS_S_COMPLETE) {
	    free(handle);
	    return (ret);
	}
    }
    if (cred_usage == GSS_C_INITIATE || cred_usage == GSS_C_BOTH) {
	ret = acquire_initiator_cred(minor_status, desired_name, time_req,
	    desired_mechs, cred_usage, handle, actual_mechs, time_rec);
    	if (ret != GSS_S_COMPLETE) {
	    free(handle);
	    return (ret);
	}
    }
    if (cred_usage == GSS_C_ACCEPT || cred_usage == GSS_C_BOTH) {
	ret = acquire_acceptor_cred(minor_status, desired_name, time_req,
	    desired_mechs, cred_usage, handle, actual_mechs, time_rec);
	if (ret != GSS_S_COMPLETE) {
	    free(handle);
	    return (ret);
	}
    }
    ret = gss_create_empty_oid_set(minor_status, &handle->mechanisms);
    if (ret == GSS_S_COMPLETE)
    	ret = gss_add_oid_set_member(minor_status, GSS_KRB5_MECHANISM,
				 &handle->mechanisms);
    if (ret == GSS_S_COMPLETE)
    	ret = gss_inquire_cred(minor_status, handle, NULL, time_rec, NULL,
			   actual_mechs);
    if (ret != GSS_S_COMPLETE) {
	if (handle->mechanisms != NULL)
		gss_release_oid_set(NULL, &handle->mechanisms);
	free(handle);
	return (ret);
    } 
    /* XXX */
    handle->lifetime = time_req;
    handle->usage = cred_usage;
    *output_cred_handle = handle;
    return (GSS_S_COMPLETE);
}