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

/* lib/crypto/krb/verify_checksum_iov.c */

/*

 * Copyright 2008 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.

 */

#include "crypto_int.h"

krb5_error_code KRB5_CALLCONV

krb5_k_verify_checksum_iov(krb5_context context,

                           krb5_cksumtype checksum_type,

                           krb5_key key,

                           krb5_keyusage usage,

                           const krb5_crypto_iov *data,

                           size_t num_data,

                           krb5_boolean *valid)

{

    const struct krb5_cksumtypes *ctp;

    krb5_error_code ret;

    krb5_data computed;

    krb5_crypto_iov *checksum;

    if (checksum_type == 0) {

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

                                            &checksum_type);

        if (ret != 0)

            return ret;

    }

    ctp = find_cksumtype(checksum_type);

    if (ctp == NULL)

        return KRB5_BAD_ENCTYPE;

    ret = verify_key(ctp, key);

    if (ret != 0)

        return ret;

    checksum = krb5int_c_locate_iov((krb5_crypto_iov *)data, num_data,

                                    KRB5_CRYPTO_TYPE_CHECKSUM);

    if (checksum == NULL || checksum->data.length != ctp->output_size)

        return KRB5_BAD_MSIZE;

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

    if (ctp->verify != NULL) {

        return ctp->verify(ctp, key, usage, data, num_data, &checksum->data,

                           valid);

    }

    ret = alloc_data(&computed, ctp->compute_size);

    if (ret != 0)

        return ret;

    ret = ctp->checksum(ctp, key, usage, data, num_data, &computed);

    if (ret == 0) {

        *valid = (k5_bcmp(computed.data, checksum->data.data,

                          ctp->output_size) == 0);

    }

    zapfree(computed.data, ctp->compute_size);

    return ret;

}

krb5_error_code KRB5_CALLCONV

krb5_c_verify_checksum_iov(krb5_context context,

                           krb5_cksumtype checksum_type,

                           const krb5_keyblock *keyblock,

                           krb5_keyusage usage,

                           const krb5_crypto_iov *data,

                           size_t num_data,

                           krb5_boolean *valid)

{

    krb5_key key;

    krb5_error_code ret;

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

    if (ret != 0)

        return ret;

    ret = krb5_k_verify_checksum_iov(context, checksum_type, key, usage, data,

                                     num_data, valid);

    krb5_k_free_key(context, key);

    return ret;

}