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_safe(krb5_context context,
 38  	     krb5_auth_context auth_context,
 39  	     const krb5_data *userdata,
 40  	     krb5_data *outbuf,
 41  	     krb5_replay_data *outdata)
 42  {
 43      krb5_error_code ret;
 44      KRB_SAFE s;
 45      u_char *buf = NULL;
 46      size_t buf_size;
 47      size_t len = 0;
 48      krb5_crypto crypto;
 49      krb5_keyblock *key;
 50      krb5_replay_data rdata;
 51  
 52      if ((auth_context->flags &
 53  	 (KRB5_AUTH_CONTEXT_RET_TIME | KRB5_AUTH_CONTEXT_RET_SEQUENCE)) &&
 54  	outdata == NULL)
 55  	return KRB5_RC_REQUIRED; /* XXX better error, MIT returns this */
 56  
 57      if (auth_context->local_subkey)
 58  	key = auth_context->local_subkey;
 59      else if (auth_context->remote_subkey)
 60  	key = auth_context->remote_subkey;
 61      else
 62  	key = auth_context->keyblock;
 63  
 64      s.pvno = 5;
 65      s.msg_type = krb_safe;
 66  
 67      memset(&rdata, 0, sizeof(rdata));
 68  
 69      s.safe_body.user_data = *userdata;
 70  
 71      krb5_us_timeofday (context, &rdata.timestamp, &rdata.usec);
 72  
 73      if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_TIME) {
 74  	s.safe_body.timestamp  = &rdata.timestamp;
 75  	s.safe_body.usec       = &rdata.usec;
 76      } else {
 77  	s.safe_body.timestamp  = NULL;
 78  	s.safe_body.usec       = NULL;
 79      }
 80  
 81      if (auth_context->flags & KRB5_AUTH_CONTEXT_RET_TIME) {
 82  	outdata->timestamp = rdata.timestamp;
 83  	outdata->usec = rdata.usec;
 84      }
 85  
 86      if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_SEQUENCE) {
 87  	rdata.seq = auth_context->local_seqnumber;
 88  	s.safe_body.seq_number = &rdata.seq;
 89      } else
 90  	s.safe_body.seq_number = NULL;
 91  
 92      if (auth_context->flags & KRB5_AUTH_CONTEXT_RET_SEQUENCE)
 93  	outdata->seq = auth_context->local_seqnumber;
 94  
 95      s.safe_body.s_address = auth_context->local_address;
 96      s.safe_body.r_address = auth_context->remote_address;
 97  
 98      s.cksum.cksumtype       = 0;
 99      s.cksum.checksum.data   = NULL;
100      s.cksum.checksum.length = 0;
101  
102      ASN1_MALLOC_ENCODE(KRB_SAFE, buf, buf_size, &s, &len, ret);
103      if (ret)
104  	return ret;
105      if(buf_size != len)
106  	krb5_abortx(context, "internal error in ASN.1 encoder");
107      ret = krb5_crypto_init(context, key, 0, &crypto);
108      if (ret) {
109  	free (buf);
110  	return ret;
111      }
112      ret = krb5_create_checksum(context,
113  			       crypto,
114  			       KRB5_KU_KRB_SAFE_CKSUM,
115  			       0,
116  			       buf,
117  			       len,
118  			       &s.cksum);
119      krb5_crypto_destroy(context, crypto);
120      if (ret) {
121  	free (buf);
122  	return ret;
123      }
124  
125      free(buf);
126      ASN1_MALLOC_ENCODE(KRB_SAFE, buf, buf_size, &s, &len, ret);
127      free_Checksum (&s.cksum);
128      if(ret)
129  	return ret;
130      if(buf_size != len)
131  	krb5_abortx(context, "internal error in ASN.1 encoder");
132  
133      outbuf->length = len;
134      outbuf->data   = buf;
135      if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_SEQUENCE)
136  	auth_context->local_seqnumber =
137  	    (auth_context->local_seqnumber + 1) & 0xFFFFFFFF;
138      return 0;
139  }