crypto/dist/heimdal/lib/krb5/rd_priv.c

   1 /*
   2  * Copyright (c) 1997-2007 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("$Heimdal: rd_priv.c 21751 2007-07-31 20:42:20Z lha $"
  37         "$NetBSD$");
  38
  39 krb5_error_code KRB5_LIB_FUNCTION
  40 krb5_rd_priv(krb5_context context,
  41              krb5_auth_context auth_context,
  42              const krb5_data *inbuf,
  43              krb5_data *outbuf,
  44              krb5_replay_data *outdata)
  45 {
  46     krb5_error_code ret;
  47     KRB_PRIV priv;
  48     EncKrbPrivPart part;
  49     size_t len;
  50     krb5_data plain;
  51     krb5_keyblock *key;
  52     krb5_crypto crypto;
  53
  54     if (outbuf)
  55         krb5_data_zero(outbuf);
  56
  57     if ((auth_context->flags &
  58          (KRB5_AUTH_CONTEXT_RET_TIME | KRB5_AUTH_CONTEXT_RET_SEQUENCE)) &&
  59         outdata == NULL) {
  60         krb5_clear_error_string (context);
  61         return KRB5_RC_REQUIRED; /* XXX better error, MIT returns this */
  62     }
  63
  64     memset(&priv, 0, sizeof(priv));
  65     ret = decode_KRB_PRIV (inbuf->data, inbuf->length, &priv, &len);
  66     if (ret) {
  67         krb5_clear_error_string (context);
  68         goto failure;
  69     }
  70     if (priv.pvno != 5) {
  71         krb5_clear_error_string (context);
  72         ret = KRB5KRB_AP_ERR_BADVERSION;
  73         goto failure;
  74     }
  75     if (priv.msg_type != krb_priv) {
  76         krb5_clear_error_string (context);
  77         ret = KRB5KRB_AP_ERR_MSG_TYPE;
  78         goto failure;
  79     }
  80
  81     if (auth_context->remote_subkey)
  82         key = auth_context->remote_subkey;
  83     else if (auth_context->local_subkey)
  84         key = auth_context->local_subkey;
  85     else
  86         key = auth_context->keyblock;
  87
  88     ret = krb5_crypto_init(context, key, 0, &crypto);
  89     if (ret)
  90         goto failure;
  91     ret = krb5_decrypt_EncryptedData(context,
  92                                      crypto,
  93                                      KRB5_KU_KRB_PRIV,
  94                                      &priv.enc_part,
  95                                      &plain);
  96     krb5_crypto_destroy(context, crypto);
  97     if (ret)
  98         goto failure;
  99
 100     ret = decode_EncKrbPrivPart (plain.data, plain.length, &part, &len);
 101     krb5_data_free (&plain);
 102     if (ret) {
 103         krb5_clear_error_string (context);
 104         goto failure;
 105     }
 106
 107     /* check sender address */
 108
 109     if (part.s_address
 110         && auth_context->remote_address
 111         && !krb5_address_compare (context,
 112                                   auth_context->remote_address,
 113                                   part.s_address)) {
 114         krb5_clear_error_string (context);
 115         ret = KRB5KRB_AP_ERR_BADADDR;
 116         goto failure_part;
 117     }
 118
 119     /* check receiver address */
 120
 121     if (part.r_address
 122         && auth_context->local_address
 123         && !krb5_address_compare (context,
 124                                   auth_context->local_address,
 125                                   part.r_address)) {
 126         krb5_clear_error_string (context);
 127         ret = KRB5KRB_AP_ERR_BADADDR;
 128         goto failure_part;
 129     }
 130
 131     /* check timestamp */
 132     if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_TIME) {
 133         krb5_timestamp sec;
 134
 135         krb5_timeofday (context, &sec);
 136         if (part.timestamp == NULL ||
 137             part.usec      == NULL ||
 138             abs(*part.timestamp - sec) > context->max_skew) {
 139             krb5_clear_error_string (context);
 140             ret = KRB5KRB_AP_ERR_SKEW;
 141             goto failure_part;
 142         }
 143     }
 144
 145     /* XXX - check replay cache */
 146
 147     /* check sequence number. since MIT krb5 cannot generate a sequence
 148        number of zero but instead generates no sequence number, we accept that
 149     */
 150
 151     if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_SEQUENCE) {
 152         if ((part.seq_number == NULL
 153              && auth_context->remote_seqnumber != 0)
 154             || (part.seq_number != NULL
 155                 && *part.seq_number != auth_context->remote_seqnumber)) {
 156             krb5_clear_error_string (context);
 157             ret = KRB5KRB_AP_ERR_BADORDER;
 158             goto failure_part;
 159         }
 160         auth_context->remote_seqnumber++;
 161     }
 162
 163     ret = krb5_data_copy (outbuf, part.user_data.data, part.user_data.length);
 164     if (ret)
 165         goto failure_part;
 166
 167     if ((auth_context->flags &
 168          (KRB5_AUTH_CONTEXT_RET_TIME | KRB5_AUTH_CONTEXT_RET_SEQUENCE))) {
 169         /* if these fields are not present in the priv-part, silently
 170            return zero */
 171         memset(outdata, 0, sizeof(*outdata));
 172         if(part.timestamp)
 173             outdata->timestamp = *part.timestamp;
 174         if(part.usec)
 175             outdata->usec = *part.usec;
 176         if(part.seq_number)
 177             outdata->seq = *part.seq_number;
 178     }
 179
 180   failure_part:
 181     free_EncKrbPrivPart (&part);
 182
 183   failure:
 184     free_KRB_PRIV (&priv);
 185     return ret;
 186 }