GSS_ADD_CRED(3) Programmer's Manual GSS_ADD_CRED(3)NAMEgss_add_cred — Construct credentials incrementally
SYNOPSIS
#include <gssapi/gssapi.h>
OM_uint32
gss_add_cred(OM_uint32 *minor_status,
const gss_cred_id_t input_cred_handle, const gss_name_t desired_name,
const gss_OID desired_mech, gss_cred_usage_t cred_usage,
OM_uint32 initiator_time_req, OM_uint32 acceptor_time_req,
gss_cred_id_t *output_cred_handle, gss_OID_set *actual_mechs,
OM_uint32 *initiator_time_rec, OM_uint32 *acceptor_time_rec);
DESCRIPTION
Adds a credential-element to a credential. The credential-element is
identified by the name of the principal to which it refers. GSS-API
implementations must impose a local access-control policy on callers of
this routine to prevent unauthorized callers from acquiring credential-
elements 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 mechanism-specific authentication data,
rather than merely acquiring a GSS-API handle to existing data. Such
functions, if required, should be defined in implementation-specific
extensions to the API.
If desired_name is GSS_C_NO_NAME, the call is interpreted as a request to
add a credential element that will invoke default behavior when passed to
gss_init_sec_context() (if cred_usage is GSS_C_INITIATE or GSS_C_BOTH) or
gss_accept_sec_context() (if cred_usage is GSS_C_ACCEPT or GSS_C_BOTH ).
This routine is expected to be used primarily by context acceptors, since
implementations are likely to provide mechanism-specific ways of obtain‐
ing GSS-API initiator credentials from the system login process. Some
implementations may therefore not support the acquisition of
GSS_C_INITIATE or GSS_C_BOTH credentials via gss_acquire_cred() for any
name other than GSS_C_NO_NAME, or a name produced by applying either
gss_inquire_cred() to a valid credential, or gss_inquire_context() to an
active context.
If credential acquisition is time-consuming for a mechanism, the mecha‐
nism may choose to delay the actual acquisition until the credential is
required (e.g. by gss_init_sec_context() or gss_accept_sec_context().)
Such mechanism-specific implementation decisions should be invisible to
the calling application; thus a call of gss_inquire_cred() immediately
following the call of gss_add_cred() must return valid credential data,
and may therefore incur the overhead of a deferred credential acquisi‐
tion.
This routine can be used to either compose a new credential containing
all credential-elements of the original in addition to the newly-acquire
credential-element, or to add the new credential-element to an existing
credential. If NULL is specified for the output_cred_handle parameter
argument, the new credential-element will be added to the credential
identified by input_cred_handle; if a valid pointer is specified for the
output_cred_handle parameter, a new credential handle will be created.
If GSS_C_NO_CREDENTIAL is specified as the input_cred_handle,
gss_add_cred() will compose a credential (and set the output_cred_handle
parameter accordingly) based on default behavior. That is, the call will
have the same effect as if the application had first made a call to
gss_acquire_cred(), specifying the same usage and passing GSS_C_NO_NAME
as the desired_name parameter to obtain an explicit credential handle
embodying default behavior, passed this credential handle to
gss_add_cred(), and finally called gss_release_cred() on the first cre‐
dential handle.
If GSS_C_NO_CREDENTIAL is specified as the input_cred_handle parameter, a
non- NULL output_cred_handle must be supplied.
PARAMETERS
minor_status Mechanism specific status code.
input_cred_handle
The credential to which a credential-element will be added.
If GSS_C_NO_CREDENTIAL is specified, the routine will com‐
pose the new credential based on default behavior (see
description above). Note that, while the credential-handle
is not modified by gss_add_cred(), the underlying creden‐
tial will be modified if output_credential_handle is NULL.
desired_name Name of principal whose credential should be acquired.
desired_mech Underlying security mechanism with which the credential may
be used.
cred_usage
GSS_C_BOTH Credential may be used either to initiate
or accept security contexts.
GSS_C_INITIATE Credential will only be used to initiate
security contexts.
GSS_C_ACCEPT Credential will only be used to accept
security contexts.
initiator_time_req
Number of seconds that the credential should remain valid
for initiating security contexts. This argument is ignored
if the composed credentials are of type GSS_C_ACCEPT.
Specify GSS_C_INDEFINITE to request that the credentials
have the maximum permitted initiator lifetime.
acceptor_time_req
Number of seconds that the credential should remain valid
for accepting security contexts. This argument is ignored
if the composed credentials are of type GSS_C_INITIATE.
Specify GSS_C_INDEFINITE to request that the credentials
have the maximum permitted initiator lifetime.
output_cred_handle
The returned credential handle, containing the new creden‐
tial-element and all the credential-elements from
input_cred_handle. If a valid pointer to a gss_cred_id_t
is supplied for this parameter, gss_add_cred() creates a
new credential handle containing all credential-elements
from the input_cred_handle and the newly acquired creden‐
tial-element; if NULL is specified for this parameter, the
newly acquired credential-element will be added to the cre‐
dential identified by input_cred_handle.
The resources associated with any credential handle
returned via this parameter must be released by the appli‐
cation after use with a call to gss_release_cred().
actual_mechs The complete set of mechanisms for which the new credential
is valid. Storage for the returned OID-set must be freed
by the application after use with a call to
gss_release_oid_set(). Specify NULL if not required.
initiator_time_rec
Actual number of seconds for which the returned credentials
will remain valid for initiating contexts using the speci‐
fied mechanism. If the implementation or mechanism does
not support expiration of credentials, the value
GSS_C_INDEFINITE will be returned. Specify NULL if not
required.
acceptor_time_rec
Actual number of seconds for which the returned credentials
will remain valid for accepting security contexts using the
specified mechanism. If the implementation or mechanism
does not support expiration of credentials, the value
GSS_C_INDEFINITE will be returned. Specify NULL if not
required.
RETURN VALUES
GSS_S_COMPLETE
Successful completion.
GSS_S_BAD_MECH
Unavailable mechanism requested.
GSS_S_BAD_NAMETYPE
Type contained within desired_name parameter is not sup‐
ported
GSS_S_BAD_NAME
Value supplied for desired_name parameter is ill-formed.
GSS_S_DUPLICATE_ELEMENT
The credential already contains an element for the
requested mechanism with overlapping usage and validity
period.
GSS_S_CREDENTIALS_EXPIRED
The required credentials could not be added because they
have expired.
GSS_S_NO_CRED
No credentials were found for the specified name.
SEE ALSOgss_init_sec_context(3), gss_accept_sec_context(3), gss_acquire_cred(3),
gss_inquire_cred(3), gss_inquire_context(3), gss_release_cred(3),
gss_release_oid_set(3)STANDARDS
RFC 2743 Generic Security Service Application Program Interface Ver‐
sion 2, Update 1
RFC 2744 Generic Security Service API Version 2 : C-bindings
HISTORY
The gss_add_cred function first appeared in FreeBSD 7.0.
AUTHORS
John Wray, Iris Associates
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