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

/*

 * Copyright (C) 1998 by the FundsXpress, INC.

 *

 * 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 FundsXpress. not be used in advertising or publicity pertaining

 * to distribution of the software without specific, written prior

 * permission.  FundsXpress makes no representations about the suitability of

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

 * or implied warranty.

 *

 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR

 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED

 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.

 */

#include "crypto_int.h"

krb5_error_code KRB5_CALLCONV

krb5_k_verify_checksum(krb5_context context, krb5_key key,

                       krb5_keyusage usage, const krb5_data *data,

                       const krb5_checksum *cksum, krb5_boolean *valid)

{

    const struct krb5_cksumtypes *ctp;

    krb5_cksumtype cksumtype;

    krb5_crypto_iov iov;

    krb5_error_code ret;

    krb5_data cksum_data;

    krb5_checksum computed;

    iov.flags = KRB5_CRYPTO_TYPE_DATA;

    iov.data = *data;

    /* A 0 checksum type means use the mandatory checksum. */

    cksumtype = cksum->checksum_type;

    if (cksumtype == 0 && key != NULL) {

        ret = krb5int_c_mandatory_cksumtype(context, key->keyblock.enctype,

                                            &cksumtype);

        if (ret)

            return ret;

    }

    ctp = find_cksumtype(cksumtype);

    if (ctp == NULL)

        return KRB5_BAD_ENCTYPE;

    ret = verify_key(ctp, key);

    if (ret != 0)

        return ret;

    /* If there's actually a verify function, call it. */

    cksum_data = make_data(cksum->contents, cksum->length);

    if (ctp->verify != NULL)

        return ctp->verify(ctp, key, usage, &iov, 1, &cksum_data, valid);

    /* Otherwise, make the checksum again, and compare. */

    if (cksum->length != ctp->output_size)

        return KRB5_BAD_MSIZE;

    ret = krb5_k_make_checksum(context, cksum->checksum_type, key, usage,

                               data, &computed);

    if (ret)

        return ret;

    *valid = (k5_bcmp(computed.contents, cksum->contents,

                      ctp->output_size) == 0);

    free(computed.contents);

    return 0;

}

krb5_error_code KRB5_CALLCONV

krb5_c_verify_checksum(krb5_context context, const krb5_keyblock *keyblock,

                       krb5_keyusage usage, const krb5_data *data,

                       const krb5_checksum *cksum, krb5_boolean *valid)

{

    krb5_key key = NULL;

    krb5_error_code ret;

    if (keyblock != NULL) {

        ret = krb5_k_create_key(context, keyblock, &key);

        if (ret != 0)

            return ret;

    }

    ret = krb5_k_verify_checksum(context, key, usage, data, cksum, valid);

    krb5_k_free_key(context, key);

    return ret;

}