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.Dd January 26, 2010
.Dt GSS_ACQUIRE_CRED 3 PRM
.Os
.Sh NAME
.Nm gss_acquire_cred
.Nd Obtain a GSS-API credential handle for pre-existing credentials
.\" This next command is for sections 2 and 3 only.
.\" .Sh LIBRARY
.Sh SYNOPSIS
.In "gssapi/gssapi.h"
.Ft OM_uint32
.Fo gss_acquire_cred
.Fa "OM_uint32 *minor_status"
.Fa "const gss_name_t desired_name"
.Fa "OM_uint32 time_req"
.Fa "const gss_OID_set desired_mechs"
.Fa "gss_cred_usage_t cred_usage"
.Fa "gss_cred_id_t *output_cred_handle"
.Fa "gss_OID_set *actual_mechs"
.Fa "OM_uint32 *time_rec"
.Fc
.Sh DESCRIPTION
Allows an application to acquire a handle for a pre-existing
credential by name.
GSS-API implementations must impose a local
access-control policy on callers of this routine to prevent
unauthorized callers from acquiring credentials to which they are not
entitled.
This routine is not intended to provide a "login to the
network" function, as such a function would involve the creation of
new credentials rather than merely acquiring a handle to existing
credentials.
Such functions, if required, should be defined in
implementation-specific extensions to the API.
.Pp
If desired_name is
.Dv GSS_C_NO_NAME ,
the call is interpreted as a
request for a credential handle that will invoke default behavior
when passed to
.Fn gss_init_sec_context
(if cred_usage is
.Dv GSS_C_INITIATE
or
.Dv GSS_C_BOTH )
or
.Fn gss_accept_sec_context
(if cred_usage is
.Dv GSS_C_ACCEPT
or
.Dv GSS_C_BOTH ).
.Pp
Mechanisms should honor the
.Fa desired_mechs
parameter,
and return a credential that is suitable to use only with the
requested mechanisms.
An exception to this is the case where one underlying credential
element can be shared by multiple mechanisms;
in this case it is permissible for an implementation to indicate all
mechanisms with which the credential element may be used.
If
.Fa desired_mechs
is an empty set, behavior is undefined.
.Pp
This routine is expected to be used primarily by context acceptors,
since implementations are likely to provide mechanism-specific ways
of obtaining GSS-API initiator credentials from the system login
process.
Some implementations may therefore not support the acquisition of
.Dv GSS_C_INITIATE
or
.Dv GSS_C_BOTH
credentials via
.Fn gss_acquire_cred
for any name other than
.Dv GSS_C_NO_NAME ,
or a name produced by applying either
.Fn gss_inquire_cred
to a valid credential, or
.Fn gss_inquire_context
to an active context.
.Pp
If credential acquisition is time-consuming for a mechanism,
the mechanism may choose to delay the actual acquisition until the
credential is required
(e.g. by
.Fn gss_init_sec_context
or
.Fn gss_accept_sec_context ).
Such mechanism-specific implementation
decisions should be invisible to the calling application;
thus a call of
.Fn gss_inquire_cred
immediately following the call of
.Fn gss_acquire_cred
must return valid credential data,
and may therefore incur the overhead of a deferred credential acquisition.
.Sh PARAMETERS
.Bl -tag -width ".It output_cred_handle"
.It desired_name
Name of principal whose credential should be acquired.
.It time_req
Number of seconds that credentials should remain valid.
Specify
.Dv GSS_C_INDEFINITE
to request that the credentials have the maximum
permitted lifetime.
.It desired_mechs
Set of underlying security mechanisms that may be used.
.Dv GSS_C_NO_OID_SET
may be used to obtain an implementation-specific default.
.It cred_usage
.Bl -tag -width "GSS_C_INITIATE"
.It GSS_C_BOTH
Credentials may be used either to initiate or accept security
contexts.
.It GSS_C_INITIATE
Credentials will only be used to initiate security contexts.
.It GSS_C_ACCEPT
Credentials will only be used to accept security contexts.
.El
.It output_cred_handle
The returned credential handle.
Resources
associated with this credential handle must be released by
the application after use with a call to
.Fn gss_release_cred .
.It actual_mechs
The set of mechanisms for which the credential is valid.
Storage associated with the returned OID-set must be released by the
application after use with a call to
.Fn gss_release_oid_set .
Specify
.Dv NULL if not required.
.It time_rec
Actual number of seconds for which the returned credentials will
remain valid.
If the implementation does not support expiration of credentials,
the value
.Dv GSS_C_INDEFINITE
will be returned.
Specify NULL if not required.
.It minor_status
Mechanism specific status code.
.El
.Sh RETURN VALUES
.Bl -tag -width ".It GSS_S_CREDENTIALS_EXPIRED"
.It GSS_S_COMPLETE
Successful completion.
.It GSS_S_BAD_MECH
Unavailable mechanism requested.
.It GSS_S_BAD_NAMETYPE
Type contained within desired_name parameter is not supported.
.It GSS_S_BAD_NAME
Value supplied for desired_name parameter is ill formed.
.It GSS_S_CREDENTIALS_EXPIRED
The credentials could not be acquired because they have expired.
.It GSS_S_NO_CRED
No credentials were found for the specified name.
.El
.Sh SEE ALSO
.Xr gss_accept_sec_context 3 ,
.Xr gss_init_sec_context 3 ,
.Xr gss_inquire_context 3 ,
.Xr gss_inquire_cred 3 ,
.Xr gss_release_cred 3 ,
.Xr gss_release_oid_set 3
.Sh STANDARDS
.Bl -tag -width ".It RFC 2743"
.It RFC 2743
Generic Security Service Application Program Interface Version 2, Update 1
.It RFC 2744
Generic Security Service API Version 2 : C-bindings
.El
.Sh HISTORY
The
.Nm
function first appeared in
.Fx 7.0 .
.Sh AUTHORS
John Wray, Iris Associates
.Sh COPYRIGHT
Copyright (C) The Internet Society (2000).  All Rights Reserved.
.Pp
This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph are
included on all such copies and derivative works.  However, this
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.Pp
The limited permissions granted above are perpetual and will not be
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.Pp
This document and the information contained herein is provided on an
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