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      1 /*	$NetBSD: mk_rep.c,v 1.2 2017/01/28 21:31:49 christos Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1997 - 2003 Kungliga Tekniska Hgskolan
      5  * (Royal Institute of Technology, Stockholm, Sweden).
      6  * All rights reserved.
      7  *
      8  * Redistribution and use in source and binary forms, with or without
      9  * modification, are permitted provided that the following conditions
     10  * are met:
     11  *
     12  * 1. Redistributions of source code must retain the above copyright
     13  *    notice, this list of conditions and the following disclaimer.
     14  *
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * 3. Neither the name of the Institute nor the names of its contributors
     20  *    may be used to endorse or promote products derived from this software
     21  *    without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
     24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
     27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     33  * SUCH DAMAGE.
     34  */
     35 
     36 #include "krb5_locl.h"
     37 
     38 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
     39 krb5_mk_rep(krb5_context context,
     40 	    krb5_auth_context auth_context,
     41 	    krb5_data *outbuf)
     42 {
     43     krb5_error_code ret;
     44     AP_REP ap;
     45     EncAPRepPart body;
     46     u_char *buf = NULL;
     47     size_t buf_size;
     48     size_t len = 0;
     49     krb5_crypto crypto;
     50 
     51     ap.pvno = 5;
     52     ap.msg_type = krb_ap_rep;
     53 
     54     memset (&body, 0, sizeof(body));
     55 
     56     body.ctime = auth_context->authenticator->ctime;
     57     body.cusec = auth_context->authenticator->cusec;
     58     if (auth_context->flags & KRB5_AUTH_CONTEXT_USE_SUBKEY) {
     59 	if (auth_context->local_subkey == NULL) {
     60 	    ret = krb5_auth_con_generatelocalsubkey(context,
     61 						    auth_context,
     62 						    auth_context->keyblock);
     63 	    if(ret) {
     64 		free_EncAPRepPart(&body);
     65 		return ret;
     66 	    }
     67 	}
     68 	ret = krb5_copy_keyblock(context, auth_context->local_subkey,
     69 				 &body.subkey);
     70 	if (ret) {
     71 	    free_EncAPRepPart(&body);
     72 	    return krb5_enomem(context);
     73 	}
     74     } else
     75 	body.subkey = NULL;
     76     if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_SEQUENCE) {
     77 	if(auth_context->local_seqnumber == 0)
     78 	    krb5_generate_seq_number (context,
     79 				      auth_context->keyblock,
     80 				      &auth_context->local_seqnumber);
     81 	ALLOC(body.seq_number, 1);
     82 	if (body.seq_number == NULL) {
     83 	    free_EncAPRepPart(&body);
     84 	    return krb5_enomem(context);
     85 	}
     86 	*(body.seq_number) = auth_context->local_seqnumber;
     87     } else
     88 	body.seq_number = NULL;
     89 
     90     ap.enc_part.etype = auth_context->keyblock->keytype;
     91     ap.enc_part.kvno  = NULL;
     92 
     93     ASN1_MALLOC_ENCODE(EncAPRepPart, buf, buf_size, &body, &len, ret);
     94     free_EncAPRepPart (&body);
     95     if(ret)
     96 	return ret;
     97     if (buf_size != len)
     98 	krb5_abortx(context, "internal error in ASN.1 encoder");
     99     ret = krb5_crypto_init(context, auth_context->keyblock,
    100 			   0 /* ap.enc_part.etype */, &crypto);
    101     if (ret) {
    102 	free (buf);
    103 	return ret;
    104     }
    105     ret = krb5_encrypt (context,
    106 			crypto,
    107 			KRB5_KU_AP_REQ_ENC_PART,
    108 			buf + buf_size - len,
    109 			len,
    110 			&ap.enc_part.cipher);
    111     krb5_crypto_destroy(context, crypto);
    112     free(buf);
    113     if (ret)
    114 	return ret;
    115 
    116     ASN1_MALLOC_ENCODE(AP_REP, outbuf->data, outbuf->length, &ap, &len, ret);
    117     if (ret == 0 && outbuf->length != len)
    118 	krb5_abortx(context, "internal error in ASN.1 encoder");
    119     free_AP_REP (&ap);
    120     return ret;
    121 }
    122