lib/krb5/mk_safe.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_safe(krb5_context context,
  40              krb5_auth_context auth_context,
  41              const krb5_data *userdata,
  42              krb5_data *outbuf,
  43              krb5_replay_data *outdata)
  44 {
  45     krb5_error_code ret;
  46     KRB_SAFE s;
  47     u_char *buf = NULL;
  48     size_t buf_size;
  49     size_t len;
  50     krb5_crypto crypto;
  51     krb5_keyblock *key;
  52     krb5_replay_data rdata;
  53
  54     if ((auth_context->flags &
  55          (KRB5_AUTH_CONTEXT_RET_TIME | KRB5_AUTH_CONTEXT_RET_SEQUENCE)) &&
  56         outdata == NULL)
  57         return KRB5_RC_REQUIRED; /* XXX better error, MIT returns this */
  58
  59     if (auth_context->local_subkey)
  60         key = auth_context->local_subkey;
  61     else if (auth_context->remote_subkey)
  62         key = auth_context->remote_subkey;
  63     else
  64         key = auth_context->keyblock;
  65
  66     s.pvno = 5;
  67     s.msg_type = krb_safe;
  68
  69     memset(&rdata, 0, sizeof(rdata));
  70
  71     s.safe_body.user_data = *userdata;
  72
  73     krb5_us_timeofday (context, &rdata.timestamp, &rdata.usec);
  74
  75     if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_TIME) {
  76         s.safe_body.timestamp  = &rdata.timestamp;
  77         s.safe_body.usec       = &rdata.usec;
  78     } else {
  79         s.safe_body.timestamp  = NULL;
  80         s.safe_body.usec       = NULL;
  81     }
  82
  83     if (auth_context->flags & KRB5_AUTH_CONTEXT_RET_TIME) {
  84         outdata->timestamp = rdata.timestamp;
  85         outdata->usec = rdata.usec;
  86     }
  87
  88     if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_SEQUENCE) {
  89         rdata.seq = auth_context->local_seqnumber;
  90         s.safe_body.seq_number = &rdata.seq;
  91     } else
  92         s.safe_body.seq_number = NULL;
  93
  94     if (auth_context->flags & KRB5_AUTH_CONTEXT_RET_SEQUENCE)
  95         outdata->seq = auth_context->local_seqnumber;
  96
  97     s.safe_body.s_address = auth_context->local_address;
  98     s.safe_body.r_address = auth_context->remote_address;
  99
 100     s.cksum.cksumtype       = 0;
 101     s.cksum.checksum.data   = NULL;
 102     s.cksum.checksum.length = 0;
 103
 104     ASN1_MALLOC_ENCODE(KRB_SAFE, buf, buf_size, &s, &len, ret);
 105     if (ret)
 106         return ret;
 107     if(buf_size != len)
 108         krb5_abortx(context, "internal error in ASN.1 encoder");
 109     ret = krb5_crypto_init(context, key, 0, &crypto);
 110     if (ret) {
 111         free (buf);
 112         return ret;
 113     }
 114     ret = krb5_create_checksum(context,
 115                                crypto,
 116                                KRB5_KU_KRB_SAFE_CKSUM,
 117                                0,
 118                                buf,
 119                                len,
 120                                &s.cksum);
 121     krb5_crypto_destroy(context, crypto);
 122     if (ret) {
 123         free (buf);
 124         return ret;
 125     }
 126
 127     free(buf);
 128     ASN1_MALLOC_ENCODE(KRB_SAFE, buf, buf_size, &s, &len, ret);
 129     free_Checksum (&s.cksum);
 130     if(ret)
 131         return ret;
 132     if(buf_size != len)
 133         krb5_abortx(context, "internal error in ASN.1 encoder");
 134
 135     outbuf->length = len;
 136     outbuf->data   = buf;
 137     if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_SEQUENCE)
 138         auth_context->local_seqnumber =
 139             (auth_context->local_seqnumber + 1) & 0xFFFFFFFF;
 140     return 0;
 141 }