/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */

/*

 * Copyright (C) 2009 by the Massachusetts Institute of Technology.

 * All rights reserved.

 *

 * Export of this software from the United States of America may

 *   require a specific license from the United States Government.

 *   It is the responsibility of any person or organization contemplating

 *   export to obtain such a license before exporting.

 *

 * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and

 * distribute this software and its documentation for any purpose and

 * without fee is hereby granted, provided that the above copyright

 * notice appear in all copies and that both that copyright notice and

 * this permission notice appear in supporting documentation, and that

 * the name of M.I.T. not be used in advertising or publicity pertaining

 * to distribution of the software without specific, written prior

 * permission.  Furthermore if you modify this software you must label

 * your software as modified software and not distribute it in such a

 * fashion that it might be confused with the original M.I.T. software.

 * M.I.T. makes no representations about the suitability of

 * this software for any purpose.  It is provided "as is" without express

 * or implied warranty.

 *

 * Functions for manipulating krb5_key structures

 */

#include "crypto_int.h"

/*

 * The krb5_key data type wraps an exposed keyblock in an opaque data

 * structure, to allow for internal optimizations such as caching of

 * derived keys.

 */

/* Create a krb5_key from the enctype and key data in a keyblock. */

krb5_error_code KRB5_CALLCONV

krb5_k_create_key(krb5_context context, const krb5_keyblock *key_data,

                  krb5_key *out)

{

    krb5_key key = NULL;

    krb5_error_code code;

    *out = NULL;

    key = malloc(sizeof(*key));

    if (key == NULL)

        return ENOMEM;

    code = krb5int_c_copy_keyblock_contents(context, key_data, &key->keyblock);

    if (code)

        goto cleanup;

    key->refcount = 1;

    key->derived = NULL;

    key->cache = NULL;

    *out = key;

    return 0;

cleanup:

    free(key);

    return code;

}

void KRB5_CALLCONV

krb5_k_reference_key(krb5_context context, krb5_key key)

{

    if (key)

        key->refcount++;

}

/* Free the memory used by a krb5_key. */

void KRB5_CALLCONV

krb5_k_free_key(krb5_context context, krb5_key key)

{

    struct derived_key *dk;

    const struct krb5_keytypes *ktp;

    if (key == NULL || --key->refcount > 0)

        return;

    /* Free the derived key cache. */

    while ((dk = key->derived) != NULL) {

        key->derived = dk->next;

        free(dk->constant.data);

        krb5_k_free_key(context, dk->dkey);

        free(dk);

    }

    krb5int_c_free_keyblock_contents(context, &key->keyblock);

    if (key->cache) {

        ktp = find_enctype(key->keyblock.enctype);

        if (ktp && ktp->enc->key_cleanup)

            ktp->enc->key_cleanup(key);

    }

    free(key);

}

/* Retrieve a copy of the keyblock from a krb5_key. */

krb5_error_code KRB5_CALLCONV

krb5_k_key_keyblock(krb5_context context, krb5_key key,

                    krb5_keyblock **key_data)

{

    return krb5int_c_copy_keyblock(context, &key->keyblock, key_data);

}

/* Retrieve the enctype of a krb5_key. */

krb5_enctype KRB5_CALLCONV

krb5_k_key_enctype(krb5_context context, krb5_key key)

{

    return key->keyblock.enctype;

}