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 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
  37 krb5_rd_priv(krb5_context context,
  38              krb5_auth_context auth_context,
  39              const krb5_data *inbuf,
  40              krb5_data *outbuf,
  41              krb5_replay_data *outdata)
  42 {
  43     krb5_error_code ret;
  44     KRB_PRIV priv;
  45     EncKrbPrivPart part;
  46     size_t len;
  47     krb5_data plain;
  48     krb5_keyblock *key;
  49     krb5_crypto crypto;
  50
  51     krb5_data_zero(outbuf);
  52
  53     if ((auth_context->flags &
  54          (KRB5_AUTH_CONTEXT_RET_TIME | KRB5_AUTH_CONTEXT_RET_SEQUENCE)))
  55     {
  56         if (outdata == NULL) {
  57             krb5_clear_error_message (context);
  58             return KRB5_RC_REQUIRED; /* XXX better error, MIT returns this */
  59         }
  60         /* if these fields are not present in the priv-part, silently
  61            return zero */
  62         memset(outdata, 0, sizeof(*outdata));
  63     }
  64
  65     memset(&priv, 0, sizeof(priv));
  66     ret = decode_KRB_PRIV (inbuf->data, inbuf->length, &priv, &len);
  67     if (ret) {
  68         krb5_clear_error_message (context);
  69         goto failure;
  70     }
  71     if (priv.pvno != 5) {
  72         krb5_clear_error_message (context);
  73         ret = KRB5KRB_AP_ERR_BADVERSION;
  74         goto failure;
  75     }
  76     if (priv.msg_type != krb_priv) {
  77         krb5_clear_error_message (context);
  78         ret = KRB5KRB_AP_ERR_MSG_TYPE;
  79         goto failure;
  80     }
  81
  82     if (auth_context->remote_subkey)
  83         key = auth_context->remote_subkey;
  84     else if (auth_context->local_subkey)
  85         key = auth_context->local_subkey;
  86     else
  87         key = auth_context->keyblock;
  88
  89     ret = krb5_crypto_init(context, key, 0, &crypto);
  90     if (ret)
  91         goto failure;
  92     ret = krb5_decrypt_EncryptedData(context,
  93                                      crypto,
  94                                      KRB5_KU_KRB_PRIV,
  95                                      &priv.enc_part,
  96                                      &plain);
  97     krb5_crypto_destroy(context, crypto);
  98     if (ret)
  99         goto failure;
 100
 101     ret = decode_EncKrbPrivPart (plain.data, plain.length, &part, &len);
 102     krb5_data_free (&plain);
 103     if (ret) {
 104         krb5_clear_error_message (context);
 105         goto failure;
 106     }
 107
 108     /* check sender address */
 109
 110     if (part.s_address
 111         && auth_context->remote_address
 112         && !krb5_address_compare (context,
 113                                   auth_context->remote_address,
 114                                   part.s_address)) {
 115         krb5_clear_error_message (context);
 116         ret = KRB5KRB_AP_ERR_BADADDR;
 117         goto failure_part;
 118     }
 119
 120     /* check receiver address */
 121
 122     if (part.r_address
 123         && auth_context->local_address
 124         && !krb5_address_compare (context,
 125                                   auth_context->local_address,
 126                                   part.r_address)) {
 127         krb5_clear_error_message (context);
 128         ret = KRB5KRB_AP_ERR_BADADDR;
 129         goto failure_part;
 130     }
 131
 132     /* check timestamp */
 133     if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_TIME) {
 134         krb5_timestamp sec;
 135
 136         krb5_timeofday (context, &sec);
 137         if (part.timestamp == NULL ||
 138             part.usec      == NULL ||
 139             labs(*part.timestamp - sec) > context->max_skew) {
 140             krb5_clear_error_message (context);
 141             ret = KRB5KRB_AP_ERR_SKEW;
 142             goto failure_part;
 143         }
 144     }
 145
 146     /* XXX - check replay cache */
 147
 148     /* check sequence number. since MIT krb5 cannot generate a sequence
 149        number of zero but instead generates no sequence number, we accept that
 150     */
 151
 152     if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_SEQUENCE) {
 153         if ((part.seq_number == NULL
 154              && auth_context->remote_seqnumber != 0)
 155             || (part.seq_number != NULL
 156                 && *part.seq_number != auth_context->remote_seqnumber)) {
 157             krb5_clear_error_message (context);
 158             ret = KRB5KRB_AP_ERR_BADORDER;
 159             goto failure_part;
 160         }
 161         auth_context->remote_seqnumber++;
 162     }
 163
 164     ret = krb5_data_copy (outbuf, part.user_data.data, part.user_data.length);
 165     if (ret)
 166         goto failure_part;
 167
 168     if ((auth_context->flags &
 169          (KRB5_AUTH_CONTEXT_RET_TIME | KRB5_AUTH_CONTEXT_RET_SEQUENCE))) {
 170         if(part.timestamp)
 171             outdata->timestamp = *part.timestamp;
 172         if(part.usec)
 173             outdata->usec = *part.usec;
 174         if(part.seq_number)
 175             outdata->seq = *part.seq_number;
 176     }
 177
 178   failure_part:
 179     free_EncKrbPrivPart (&part);
 180
 181   failure:
 182     free_KRB_PRIV (&priv);
 183     return ret;
 184 }