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 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 }