- acquire a handle for a pre-existing credential by name
cc [ flag... ] file... -lgss [ library... ] #include <gssapi/gssapi.h> OM_uint32 gss_acquire_cred(OM_uint32 *minor_status, const gss_name_t *desired_name, OM_uint32 time_req, const gss_OID_set desired_mech, gss_cred_usage_t cred_usage, gss_cred_id_t * output_cred_handle, gss_OID_set *actual_mechs, OM_uint32 *time_rec);
The gss_acquire_cred() function allows an application to acquire a handle for a pre-existing credential by name. This routine is not intended as a function to login to the network; a function for login to the network would involve creating new credentials rather than merely acquiring a handle to existing credentials.
If desired_name is GSS_C_NO_NAME, the call is interpreted as a request for a credential handle that will invoke default behavior when passed to gss_init_sec_context(3GSS) (if cred_usage is GSS_C_INITIATE or GSS_C_BOTH) or gss_accept_sec_context(3GSS) (if cred_usage is GSS_C_ACCEPT or GSS_C_BOTH).
Normally gss_acquire_cred() returns a credential that is valid only for the mechanisms requested by the desired_mechs argument. However, if multiple mechanisms can share a single credential element, the function returns all the mechanisms for which the credential is valid in the actual_mechs argument.
gss_acquire_cred() is intended to be used primarily by context acceptors, since the GSS-API routines obtain initiator credentials through the system login process. Accordingly, you may not acquire GSS_C_INITIATE or GSS_C_BOTH credentials by means of gss_acquire_cred() for any name other than GSS_C_NO_NAME. Alternatively, you may acquire GSS_C_INITIATE or GSS_C_BOTH credentials for a name produced when gss_inquire_cred(3GSS) is applied to a valid credential, or when gss_inquire_context(3GSS) is applied to an active context.
If credential acquisition is time-consuming for a mechanism, the mechanism may choose to delay the actual acquisition until the credential is required, for example, by gss_init_sec_context(3GSS) or by gss_accept_sec_context(3GSS). Such mechanism-specific implementations are, however, invisible to the calling application; thus a call of gss_inquire_cred(3GSS) immediately following the call of gss_acquire_cred() will return valid credential data and incur the overhead of a deferred credential acquisition.
The parameter descriptions for gss_acquire_cred() follow:
The name of the principal for which a credential should be acquired.
The number of seconds that credentials remain valid. Specify GSS_C_INDEFINITE to request that the credentials have the maximum permitted lifetime
The set of underlying security mechanisms that may be used. GSS_C_NO_OID_SET may be used to obtain a default.
A flag that indicates how this credential should be used. If the flag is GSS_C_ACCEPT, then credentials will be used only to accept security credentials. GSS_C_INITIATE indicates that credentials will be used only to initiate security credentials. If the flag is GSS_C_BOTH, then credentials may be used either to initiate or accept security contexts.
The returned credential handle. Resources associated with this credential handle must be released by the application after use with a call to gss_release_cred(3GSS)
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 gss_release_oid_set(3GSS). Specify NULL if not required.
Actual number of seconds for which the returned credentials will remain valid. Specify NULL if not required.
Mechanism specific status code.
gss_acquire_cred() may return the following status code:
An unavailable mechanism has been requested.
The type contained within the desired_name parameter is not supported.
The value supplied for desired_name parameter is ill formed.
The credentials could not be acquired because they have expired.
No credentials were found for the specified name.
The underlying mechanism detected an error for which no specific GSS status code is defined. The mechanism-specific status code reported by means of the minor_status parameter details the error condition.
See attributes(5) for descriptions of the following attributes: