crypto/external/bsd/heimdal/dist/lib/krb5/rd_safe.c

   1 /*      $NetBSD: rd_safe.c,v 1.1.1.2 2014/04/24 12:45:51 pettai Exp $   */
   2
   3 /*
   4  * Copyright (c) 1997 - 2003 Kungliga Tekniska Högskolan
   5  * (Royal Institute of Technology, Stockholm, Sweden).
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  *
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  *
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * 3. Neither the name of the Institute nor the names of its contributors
  20  *    may be used to endorse or promote products derived from this software
  21  *    without specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  */
  35
  36 #include "krb5_locl.h"
  37
  38 static krb5_error_code
  39 verify_checksum(krb5_context context,
  40                 krb5_auth_context auth_context,
  41                 KRB_SAFE *safe)
  42 {
  43     krb5_error_code ret;
  44     u_char *buf;
  45     size_t buf_size;
  46     size_t len = 0;
  47     Checksum c;
  48     krb5_crypto crypto;
  49     krb5_keyblock *key;
  50
  51     c = safe->cksum;
  52     safe->cksum.cksumtype       = 0;
  53     safe->cksum.checksum.data   = NULL;
  54     safe->cksum.checksum.length = 0;
  55
  56     ASN1_MALLOC_ENCODE(KRB_SAFE, buf, buf_size, safe, &len, ret);
  57     if(ret)
  58         return ret;
  59     if(buf_size != len)
  60         krb5_abortx(context, "internal error in ASN.1 encoder");
  61
  62     if (auth_context->remote_subkey)
  63         key = auth_context->remote_subkey;
  64     else if (auth_context->local_subkey)
  65         key = auth_context->local_subkey;
  66     else
  67         key = auth_context->keyblock;
  68
  69     ret = krb5_crypto_init(context, key, 0, &crypto);
  70     if (ret)
  71         goto out;
  72     ret = krb5_verify_checksum (context,
  73                                 crypto,
  74                                 KRB5_KU_KRB_SAFE_CKSUM,
  75                                 buf + buf_size - len,
  76                                 len,
  77                                 &c);
  78     krb5_crypto_destroy(context, crypto);
  79 out:
  80     safe->cksum = c;
  81     free (buf);
  82     return ret;
  83 }
  84
  85 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
  86 krb5_rd_safe(krb5_context context,
  87              krb5_auth_context auth_context,
  88              const krb5_data *inbuf,
  89              krb5_data *outbuf,
  90              krb5_replay_data *outdata)
  91 {
  92     krb5_error_code ret;
  93     KRB_SAFE safe;
  94     size_t len;
  95
  96     krb5_data_zero(outbuf);
  97
  98     if ((auth_context->flags &
  99          (KRB5_AUTH_CONTEXT_RET_TIME | KRB5_AUTH_CONTEXT_RET_SEQUENCE)))
 100     {
 101         if (outdata == NULL) {
 102             krb5_set_error_message(context, KRB5_RC_REQUIRED,
 103                                    N_("rd_safe: need outdata "
 104                                       "to return data", ""));
 105             return KRB5_RC_REQUIRED; /* XXX better error, MIT returns this */
 106         }
 107         /* if these fields are not present in the safe-part, silently
 108            return zero */
 109         memset(outdata, 0, sizeof(*outdata));
 110     }
 111
 112     ret = decode_KRB_SAFE (inbuf->data, inbuf->length, &safe, &len);
 113     if (ret)
 114         return ret;
 115     if (safe.pvno != 5) {
 116         ret = KRB5KRB_AP_ERR_BADVERSION;
 117         krb5_clear_error_message (context);
 118         goto failure;
 119     }
 120     if (safe.msg_type != krb_safe) {
 121         ret = KRB5KRB_AP_ERR_MSG_TYPE;
 122         krb5_clear_error_message (context);
 123         goto failure;
 124     }
 125     if (!krb5_checksum_is_keyed(context, safe.cksum.cksumtype)
 126         || !krb5_checksum_is_collision_proof(context, safe.cksum.cksumtype)) {
 127         ret = KRB5KRB_AP_ERR_INAPP_CKSUM;
 128         krb5_clear_error_message (context);
 129         goto failure;
 130     }
 131
 132     /* check sender address */
 133
 134     if (safe.safe_body.s_address
 135         && auth_context->remote_address
 136         && !krb5_address_compare (context,
 137                                   auth_context->remote_address,
 138                                   safe.safe_body.s_address)) {
 139         ret = KRB5KRB_AP_ERR_BADADDR;
 140         krb5_clear_error_message (context);
 141         goto failure;
 142     }
 143
 144     /* check receiver address */
 145
 146     if (safe.safe_body.r_address
 147         && auth_context->local_address
 148         && !krb5_address_compare (context,
 149                                   auth_context->local_address,
 150                                   safe.safe_body.r_address)) {
 151         ret = KRB5KRB_AP_ERR_BADADDR;
 152         krb5_clear_error_message (context);
 153         goto failure;
 154     }
 155
 156     /* check timestamp */
 157     if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_TIME) {
 158         krb5_timestamp sec;
 159
 160         krb5_timeofday (context, &sec);
 161
 162         if (safe.safe_body.timestamp == NULL ||
 163             safe.safe_body.usec      == NULL ||
 164             abs(*safe.safe_body.timestamp - sec) > context->max_skew) {
 165             ret = KRB5KRB_AP_ERR_SKEW;
 166             krb5_clear_error_message (context);
 167             goto failure;
 168         }
 169     }
 170     /* XXX - check replay cache */
 171
 172     /* check sequence number. since MIT krb5 cannot generate a sequence
 173        number of zero but instead generates no sequence number, we accept that
 174     */
 175
 176     if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_SEQUENCE) {
 177         if ((safe.safe_body.seq_number == NULL
 178              && auth_context->remote_seqnumber != 0)
 179             || (safe.safe_body.seq_number != NULL
 180                 && *safe.safe_body.seq_number !=
 181                 auth_context->remote_seqnumber)) {
 182             ret = KRB5KRB_AP_ERR_BADORDER;
 183             krb5_clear_error_message (context);
 184             goto failure;
 185         }
 186         auth_context->remote_seqnumber++;
 187     }
 188
 189     ret = verify_checksum (context, auth_context, &safe);
 190     if (ret)
 191         goto failure;
 192
 193     outbuf->length = safe.safe_body.user_data.length;
 194     outbuf->data   = malloc(outbuf->length);
 195     if (outbuf->data == NULL && outbuf->length != 0) {
 196         ret = ENOMEM;
 197         krb5_set_error_message(context, ret, N_("malloc: out of memory", ""));
 198         krb5_data_zero(outbuf);
 199         goto failure;
 200     }
 201     memcpy (outbuf->data, safe.safe_body.user_data.data, outbuf->length);
 202
 203     if ((auth_context->flags &
 204          (KRB5_AUTH_CONTEXT_RET_TIME | KRB5_AUTH_CONTEXT_RET_SEQUENCE))) {
 205
 206         if(safe.safe_body.timestamp)
 207             outdata->timestamp = *safe.safe_body.timestamp;
 208         if(safe.safe_body.usec)
 209             outdata->usec = *safe.safe_body.usec;
 210         if(safe.safe_body.seq_number)
 211             outdata->seq = *safe.safe_body.seq_number;
 212     }
 213
 214   failure:
 215     free_KRB_SAFE (&safe);
 216     return ret;
 217 }