lib/krb5/mk_rep.c

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