Manual Pages  — KRB5_GET_CREDENTIALS

krb5_get_credentials, krb5_get_credentials_with_flags, krb5_get_kdc_cred, krb5_get_renewed_creds – get credentials from the KDC using krbtgt

LIBRARY SYNOPSIS DESCRIPTION EXAMPLES SEE ALSO

Kerberos 5 Library (libkrb5, -lkrb5)

#include <krb5.h>

krb5_error_code
krb5_get_credentials(krb5_context context, krb5_flags options, krb5_ccache ccache, krb5_creds *in_creds, krb5_creds **out_creds);

krb5_error_code
krb5_get_credentials_with_flags(krb5_context context, krb5_flags options, krb5_kdc_flags flags, krb5_ccache ccache, krb5_creds *in_creds, krb5_creds **out_creds);

krb5_error_code
krb5_get_kdc_cred(krb5_context context, krb5_ccache id, krb5_kdc_flags flags, krb5_addresses *addresses, Ticket *second_ticket, krb5_creds *in_creds, krb5_creds **out_creds);

krb5_error_code
krb5_get_renewed_creds(krb5_context context, krb5_creds *creds, krb5_const_principal client, krb5_ccache ccache, const char *in_tkt_service);

krb5_get_credentials_with_flags() get credentials specified by in_creds->server and in_creds->client (the rest of the in_creds structure is ignored) by first looking in the ccache and if doesn't exists or is expired, fetch the credential from the KDC using the krbtgt in ccache. The credential is returned in out_creds and should be freed using the function krb5_free_creds().

Valid flags to pass into options argument 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 option 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.

Flags are KDCOptions, note the caller must fill in the bit-field and not use the integer associated structure.

krb5_get_credentials() works the same way as krb5_get_credentials_with_flags() except that the flags field is missing.

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.

krb5_get_renewed_creds() renews a credential given by in_tkt_service (if NULL the default krbtgt) using the credential cache ccache. The result is stored in creds and should be freed using krb5_free_creds.

Here is a example function that get a credential from a credential cache id or the KDC and returns it to the caller.

#include <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;
}