June 15, 2006 KRB5_GET_CREDS 3

### NAME

krb5_get_creds, krb5_get_creds_opt_add_options, krb5_get_creds_opt_alloc, krb5_get_creds_opt_free, krb5_get_creds_opt_set_enctype, krb5_get_creds_opt_set_impersonate, krb5_get_creds_opt_set_options, krb5_get_creds_opt_set_ticket - get credentials from the KDC

### LIBRARY

Kerberos 5 Library (libkrb5, -lkrb5)

### SYNOPSIS

```krb5_error_code` krb5_get_creds(`` ```krb5_context context` ```krb5_get_creds_opt opt` ```krb5_ccache ccache` ```krb5_const_principal inprinc` ```krb5_creds **out_creds` )
```void` krb5_get_creds_opt_add_options(`` ```krb5_context context` ```krb5_get_creds_opt opt` ```krb5_flags options` )
```krb5_error_code` krb5_get_creds_opt_alloc(`` ```krb5_context context` ```krb5_get_creds_opt *opt` )
```void` krb5_get_creds_opt_free(`` ```krb5_context context` ```krb5_get_creds_opt opt` )
```void` krb5_get_creds_opt_set_enctype(`` ```krb5_context context` ```krb5_get_creds_opt opt` ```krb5_enctype enctype` )
```krb5_error_code` krb5_get_creds_opt_set_impersonate(`` ```krb5_context context` ```krb5_get_creds_opt opt` ```krb5_const_principal self` )
```void` krb5_get_creds_opt_set_options(`` ```krb5_context context` ```krb5_get_creds_opt opt` ```krb5_flags options` )
```krb5_error_code` krb5_get_creds_opt_set_ticket(`` ```krb5_context context` ```krb5_get_creds_opt opt` ```const Ticket *ticket` )

### DESCRIPTION

krb5_get_creds(``) fetches credentials specified by ```opt` by first looking in the ```ccache`, and then it doesn't exists, fetch the credential from the KDC using the krbtgts in ```ccache`. The credential is returned in ```out_creds` and should be freed using the function krb5_free_creds(``).

The structure ```krb5_get_creds_opt` controls the behavior of krb5_get_creds(``). The structure is opaque to consumers that can set the content of the structure with accessors functions. All accessor functions make copies of the data that is passed into accessor functions, so external consumers free the memory before calling krb5_get_creds(``).

The structure ```krb5_get_creds_opt` is allocated with krb5_get_creds_opt_alloc(``) and freed with krb5_get_creds_opt_free(``). The free function also frees the content of the structure set by the accessor functions.

krb5_get_creds_opt_add_options(``) and krb5_get_creds_opt_set_options(``) adds and sets options to the structure . The possible options to set are

KRB5_GC_CACHED
  Only check the ```ccache`, don't got out on network to fetch credential.
KRB5_GC_USER_USER
  request a user to user ticket. This options doesn't store the resulting user to user credential in the ```ccache`.
KRB5_GC_EXPIRED_OK
  returns the credential even if it is expired, default behavior is trying to refetch the credential from the KDC.
KRB5_GC_NO_STORE
  Do not store the resulting credentials in the ```ccache`.

krb5_get_creds_opt_set_enctype(``) sets the preferred encryption type of the application. Don't set this unless you have to since if there is no match in the KDC, the function call will fail.

krb5_get_creds_opt_set_impersonate(``) sets the principal to impersonate., Returns a ticket that have the impersonation principal as a client and the requestor as the service. Note that the requested principal have to be the same as the client principal in the krbtgt.

krb5_get_creds_opt_set_ticket(``) sets the extra ticket used in user-to-user or contrained delegation use case.

### SEE ALSO

krb5(3), krb5_get_credentials(3), krb5.conf(5)