mk_priv.c

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/*
 * Copyright (c) 1997 - 2003 Kungliga Tekniska H鰃skolan
 * (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 <krb5_locl.h>

RCSID("$Id: mk_priv.c 16680 2006-02-01 12:39:26Z lha $");

      
krb5_error_code KRB5_LIB_FUNCTION
krb5_mk_priv(krb5_context context,
	     krb5_auth_context auth_context,
	     const krb5_data *userdata,
	     krb5_data *outbuf,
	     krb5_replay_data *outdata)
{
    krb5_error_code ret;
    KRB_PRIV s;
    EncKrbPrivPart part;
    u_char *buf = NULL;
    size_t buf_size;
    size_t len;
    krb5_crypto crypto;
    krb5_keyblock *key;
    krb5_replay_data rdata;

    if ((auth_context->flags & 
	 (KRB5_AUTH_CONTEXT_RET_TIME | KRB5_AUTH_CONTEXT_RET_SEQUENCE)) &&
	outdata == NULL)
	return KRB5_RC_REQUIRED; /* XXX better error, MIT returns this */

    if (auth_context->local_subkey)
	key = auth_context->local_subkey;
    else if (auth_context->remote_subkey)
	key = auth_context->remote_subkey;
    else
	key = auth_context->keyblock;

    memset(&rdata, 0, sizeof(rdata));

    part.user_data = *userdata;

    krb5_us_timeofday (context, &rdata.timestamp, &rdata.usec);

    if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_TIME) {
	part.timestamp = &rdata.timestamp;
	part.usec      = &rdata.usec;
    } else {
	part.timestamp = NULL;
	part.usec      = NULL;
    }

    if (auth_context->flags & KRB5_AUTH_CONTEXT_RET_TIME) {
	outdata->timestamp = rdata.timestamp;
	outdata->usec = rdata.usec;
    }

    if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_SEQUENCE) {
	rdata.seq = auth_context->local_seqnumber;
	part.seq_number = &rdata.seq;
    } else
	part.seq_number = NULL;

    if (auth_context->flags & KRB5_AUTH_CONTEXT_RET_SEQUENCE)
	outdata->seq = auth_context->local_seqnumber;
    
    part.s_address = auth_context->local_address;
    part.r_address = auth_context->remote_address;

    krb5_data_zero (&s.enc_part.cipher);

    ASN1_MALLOC_ENCODE(EncKrbPrivPart, buf, buf_size, &part, &len, ret);
    if (ret)
	goto fail;
    if (buf_size != len)
	krb5_abortx(context, "internal error in ASN.1 encoder");

    s.pvno = 5;
    s.msg_type = krb_priv;
    s.enc_part.etype = key->keytype;
    s.enc_part.kvno = NULL;

    ret = krb5_crypto_init(context, key, 0, &crypto);
    if (ret) {
	free (buf);
	return ret;
    }
    ret = krb5_encrypt (context, 
			crypto,
			KRB5_KU_KRB_PRIV,
			buf + buf_size - len, 
			len,
			&s.enc_part.cipher);
    krb5_crypto_destroy(context, crypto);
    if (ret) {
	free(buf);
	return ret;
    }
    free(buf);


    ASN1_MALLOC_ENCODE(KRB_PRIV, buf, buf_size, &s, &len, ret);
    if (ret)
	goto fail;
    if (buf_size != len)
	krb5_abortx(context, "internal error in ASN.1 encoder");

    krb5_data_free (&s.enc_part.cipher);

    ret = krb5_data_copy(outbuf, buf + buf_size - len, len);
    if (ret) {
	krb5_set_error_string (context, "malloc: out of memory");
	free(buf);
	return ENOMEM;
    }
    free (buf);
    if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_SEQUENCE)
	auth_context->local_seqnumber =
	    (auth_context->local_seqnumber + 1) & 0xFFFFFFFF;
    return 0;

  fail:
    free (buf);
    krb5_data_free (&s.enc_part.cipher);
    return ret;
}