common.c

/*
 * 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 */