/*
 * Copyright (c) 1997-2004 Kungliga Tekniska Högskolan
 * (Royal Institute of Technology, Stockholm, Sweden).
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * 3. Neither the name of the Institute nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include "rsh_locl.h"
RCSID("$Id$");

#if defined(KRB5)

#ifdef KRB5
int key_usage = 1026;

void *ivec_in[2];
void *ivec_out[2];

void
init_ivecs(int client, int have_errsock)
{
    size_t blocksize;

    krb5_crypto_getblocksize(context, crypto, &blocksize);

    ivec_in[0] = malloc(blocksize);
    memset(ivec_in[0], client, blocksize);

    if(have_errsock) {
        ivec_in[1] = malloc(blocksize);
        memset(ivec_in[1], 2 | client, blocksize);
    } else
        ivec_in[1] = ivec_in[0];

    ivec_out[0] = malloc(blocksize);
    memset(ivec_out[0], !client, blocksize);

    if(have_errsock) {
        ivec_out[1] = malloc(blocksize);
        memset(ivec_out[1], 2 | !client, blocksize);
    } else
        ivec_out[1] = ivec_out[0];
}
#endif


ssize_t
do_read (int fd, void *buf, size_t sz, void *ivec)
{
    if (do_encrypt) {
#ifdef KRB5
        if(auth_method == AUTH_KRB5) {
            krb5_error_code ret;
            uint32_t len, outer_len;
            int status;
            krb5_data data;
            void *edata;

            ret = krb5_net_read (context, &fd, &len, 4);
            if (ret <= 0)
                return ret;
            len = ntohl(len);
            if (len > sz)
                abort ();
            /* ivec will be non null for protocol version 2 */
            if(ivec != NULL)
                outer_len = krb5_get_wrapped_length (context, crypto, len + 4);
            else
                outer_len = krb5_get_wrapped_length (context, crypto, len);
            edata = malloc (outer_len);
            if (edata == NULL)
                errx (1, "malloc: cannot allocate %u bytes", outer_len);
            ret = krb5_net_read (context, &fd, edata, outer_len);
            if (ret <= 0) {
                free(edata);
                return ret;
            }

            status = krb5_decrypt_ivec(context, crypto, key_usage,
                                       edata, outer_len, &data, ivec);
            free (edata);

            if (status)
                krb5_err (context, 1, status, "decrypting data");
            if(ivec != NULL) {
                unsigned long l;
                if(data.length < len + 4)
                    errx (1, "data received is too short");
                _krb5_get_int(data.data, &l, 4);
                if(l != len)
                    errx (1, "inconsistency in received data");
                memcpy (buf, (unsigned char *)data.data+4, len);
            } else
                memcpy (buf, data.data, len);
            krb5_data_free (&data);
            return len;
        } else
#endif /* KRB5 */
            abort ();
    } else
        return read (fd, buf, sz);
}

ssize_t
do_write (int fd, void *buf, size_t sz, void *ivec)
{
    if (do_encrypt) {
#ifdef KRB5
        if(auth_method == AUTH_KRB5) {
            krb5_error_code status;
            krb5_data data;
            unsigned char len[4];
            int ret;

            _krb5_put_int(len, sz, 4);
            if(ivec != NULL) {
                unsigned char *tmp = malloc(sz + 4);
                if(tmp == NULL)
                    err(1, "malloc");
                _krb5_put_int(tmp, sz, 4);
                memcpy(tmp + 4, buf, sz);
                status = krb5_encrypt_ivec(context, crypto, key_usage,
                                           tmp, sz + 4, &data, ivec);
                free(tmp);
            } else
                status = krb5_encrypt_ivec(context, crypto, key_usage,
                                           buf, sz, &data, ivec);

            if (status)
                krb5_err(context, 1, status, "encrypting data");

            ret = krb5_net_write (context, &fd, len, 4);
            if (ret != 4)
                return ret;
            ret = krb5_net_write (context, &fd, data.data, data.length);
            if (ret != data.length)
                return ret;
            free (data.data);
            return sz;
        } else
#endif /* KRB5 */
            abort();
    } else
        return write (fd, buf, sz);
}
#endif /* KRB5 */