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 RCSID("$Id$");
  37
  38 krb5_error_code KRB5_LIB_FUNCTION
  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;
  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                 krb5_set_error_string (context,
  65                                        "krb5_mk_rep: generating subkey");
  66                 free_EncAPRepPart(&body);
  67                 return ret;
  68             }
  69         }
  70         ret = krb5_copy_keyblock(context, auth_context->local_subkey,
  71                                  &body.subkey);
  72         if (ret) {
  73             krb5_set_error_string (context,
  74                                    "krb5_copy_keyblock: out of memory");
  75             free_EncAPRepPart(&body);
  76             return ENOMEM;
  77         }
  78     } else
  79         body.subkey = NULL;
  80     if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_SEQUENCE) {
  81         if(auth_context->local_seqnumber == 0)
  82             krb5_generate_seq_number (context,
  83                                       auth_context->keyblock,
  84                                       &auth_context->local_seqnumber);
  85         ALLOC(body.seq_number, 1);
  86         if (body.seq_number == NULL) {
  87             krb5_set_error_string (context, "malloc: out of memory");
  88             free_EncAPRepPart(&body);
  89             return ENOMEM;
  90         }
  91         *(body.seq_number) = auth_context->local_seqnumber;
  92     } else
  93         body.seq_number = NULL;
  94
  95     ap.enc_part.etype = auth_context->keyblock->keytype;
  96     ap.enc_part.kvno  = NULL;
  97
  98     ASN1_MALLOC_ENCODE(EncAPRepPart, buf, buf_size, &body, &len, ret);
  99     free_EncAPRepPart (&body);
 100     if(ret)
 101         return ret;
 102     if (buf_size != len)
 103         krb5_abortx(context, "internal error in ASN.1 encoder");
 104     ret = krb5_crypto_init(context, auth_context->keyblock,
 105                            0 /* ap.enc_part.etype */, &crypto);
 106     if (ret) {
 107         free (buf);
 108         return ret;
 109     }
 110     ret = krb5_encrypt (context,
 111                         crypto,
 112                         KRB5_KU_AP_REQ_ENC_PART,
 113                         buf + buf_size - len,
 114                         len,
 115                         &ap.enc_part.cipher);
 116     krb5_crypto_destroy(context, crypto);
 117     free(buf);
 118     if (ret)
 119         return ret;
 120
 121     ASN1_MALLOC_ENCODE(AP_REP, outbuf->data, outbuf->length, &ap, &len, ret);
 122     if (ret == 0 && outbuf->length != len)
 123         krb5_abortx(context, "internal error in ASN.1 encoder");
 124     free_AP_REP (&ap);
 125     return ret;
 126 }