.\"	$NetBSD: krb5_get_credentials.3,v 1.2 2017/01/28 21:31:49 christos Exp $
.\"
.\" Copyright (c) 2004 - 2005 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.
.\"
.\" Id
.\"
.Dd July 26, 2004
.Dt KRB5_GET_CREDENTIALS 3
.Os
.Sh NAME
.Nm krb5_get_credentials ,
.Nm krb5_get_credentials_with_flags ,
.Nm krb5_get_kdc_cred ,
.Nm krb5_get_renewed_creds
.Nd get credentials from the KDC using krbtgt
.Sh LIBRARY
Kerberos 5 Library (libkrb5, -lkrb5)
.Sh SYNOPSIS
.In krb5/krb5.h
.Ft krb5_error_code
.Fo krb5_get_credentials
.Fa "krb5_context context"
.Fa "krb5_flags options"
.Fa "krb5_ccache ccache"
.Fa "krb5_creds *in_creds"
.Fa "krb5_creds **out_creds"
.Fc
.Ft krb5_error_code
.Fo krb5_get_credentials_with_flags
.Fa "krb5_context context"
.Fa "krb5_flags options"
.Fa "krb5_kdc_flags flags"
.Fa "krb5_ccache ccache"
.Fa "krb5_creds *in_creds"
.Fa "krb5_creds **out_creds"
.Fc
.Ft krb5_error_code
.Fo krb5_get_kdc_cred
.Fa "krb5_context context"
.Fa "krb5_ccache id"
.Fa "krb5_kdc_flags flags"
.Fa "krb5_addresses *addresses"
.Fa "Ticket  *second_ticket"
.Fa "krb5_creds *in_creds"
.Fa "krb5_creds **out_creds"
.Fc
.Ft krb5_error_code
.Fo krb5_get_renewed_creds
.Fa "krb5_context context"
.Fa "krb5_creds *creds"
.Fa "krb5_const_principal client"
.Fa "krb5_ccache ccache"
.Fa "const char *in_tkt_service"
.Fc
.Sh DESCRIPTION
.Fn krb5_get_credentials_with_flags
get credentials specified by
.Fa in_creds->server
and
.Fa in_creds->client
(the rest of the
.Fa in_creds
structure is ignored)
by first looking in the
.Fa ccache
and if doesn't exists or is expired, fetch the credential from the KDC
using the krbtgt in
.Fa ccache .
The credential is returned in
.Fa out_creds
and should be freed using the function
.Fn krb5_free_creds .
.Pp
Valid flags to pass into
.Fa options
argument are:
.Pp
.Bl -tag -width "KRB5_GC_EXPIRED_OK" -compact
.It KRB5_GC_CACHED
Only check the
.Fa ccache ,
don't got out on network to fetch credential.
.It KRB5_GC_USER_USER
Request a user to user ticket.
This option doesn't store the resulting user to user credential in
the
.Fa ccache .
.It KRB5_GC_EXPIRED_OK
returns the credential even if it is expired, default behavior is trying
to refetch the credential from the KDC.
.El
.Pp
.Fa Flags
are KDCOptions, note the caller must fill in the bit-field and not
use the integer associated structure.
.Pp
.Fn krb5_get_credentials
works the same way as
.Fn krb5_get_credentials_with_flags
except that the
.Fa flags
field is missing.
.Pp
.Fn krb5_get_kdc_cred
does the same as the functions above, but the caller must fill in all
the information andits closer to the wire protocol.
.Pp
.Fn krb5_get_renewed_creds
renews a credential given by
.Fa in_tkt_service
(if
.Dv NULL
the default
.Li krbtgt )
using the credential cache
.Fa ccache .
The result is stored in
.Fa creds
and should be freed using
.Fa krb5_free_creds .
.Sh EXAMPLES
Here is a example function that get a credential from a credential cache
.Fa id
or the KDC and returns it to the caller.
.Bd -literal
#include <krb5/krb5.h>

int
getcred(krb5_context context, krb5_ccache id, krb5_creds **creds)
{
    krb5_error_code ret;
    krb5_creds in;

    ret = krb5_parse_name(context, "client@EXAMPLE.COM",
			  &in.client);
    if (ret)
	krb5_err(context, 1, ret, "krb5_parse_name");

    ret = krb5_parse_name(context, "host/server.example.com@EXAMPLE.COM",
			  &in.server);
    if (ret)
	krb5_err(context, 1, ret, "krb5_parse_name");

    ret = krb5_get_credentials(context, 0, id, &in, creds);
    if (ret)
	krb5_err(context, 1, ret, "krb5_get_credentials");

    return 0;
}
.Ed
.Sh SEE ALSO
.Xr krb5 3 ,
.Xr krb5_get_forwarded_creds 3 ,
.Xr krb5.conf 5