lib/krb5/rd_cred.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 static krb5_error_code
  37 compare_addrs(krb5_context context,
  38               krb5_address *a,
  39               krb5_address *b,
  40               const char *message)
  41 {
  42     char a_str[64], b_str[64];
  43     size_t len;
  44
  45     if(krb5_address_compare (context, a, b))
  46         return 0;
  47
  48     krb5_print_address (a, a_str, sizeof(a_str), &len);
  49     krb5_print_address (b, b_str, sizeof(b_str), &len);
  50     krb5_set_error_message(context, KRB5KRB_AP_ERR_BADADDR,
  51                            "%s: %s != %s", message, b_str, a_str);
  52     return KRB5KRB_AP_ERR_BADADDR;
  53 }
  54
  55 krb5_error_code KRB5_LIB_FUNCTION
  56 krb5_rd_cred(krb5_context context,
  57              krb5_auth_context auth_context,
  58              krb5_data *in_data,
  59              krb5_creds ***ret_creds,
  60              krb5_replay_data *outdata)
  61 {
  62     krb5_error_code ret;
  63     size_t len;
  64     KRB_CRED cred;
  65     EncKrbCredPart enc_krb_cred_part;
  66     krb5_data enc_krb_cred_part_data;
  67     krb5_crypto crypto;
  68     int i;
  69
  70     memset(&enc_krb_cred_part, 0, sizeof(enc_krb_cred_part));
  71
  72     if ((auth_context->flags &
  73          (KRB5_AUTH_CONTEXT_RET_TIME | KRB5_AUTH_CONTEXT_RET_SEQUENCE)) &&
  74         outdata == NULL)
  75         return KRB5_RC_REQUIRED; /* XXX better error, MIT returns this */
  76
  77     *ret_creds = NULL;
  78
  79     ret = decode_KRB_CRED(in_data->data, in_data->length,
  80                           &cred, &len);
  81     if(ret) {
  82         krb5_clear_error_message(context);
  83         return ret;
  84     }
  85
  86     if (cred.pvno != 5) {
  87         ret = KRB5KRB_AP_ERR_BADVERSION;
  88         krb5_clear_error_message (context);
  89         goto out;
  90     }
  91
  92     if (cred.msg_type != krb_cred) {
  93         ret = KRB5KRB_AP_ERR_MSG_TYPE;
  94         krb5_clear_error_message (context);
  95         goto out;
  96     }
  97
  98     if (cred.enc_part.etype == ETYPE_NULL) {
  99         /* DK: MIT GSS-API Compatibility */
 100         enc_krb_cred_part_data.length = cred.enc_part.cipher.length;
 101         enc_krb_cred_part_data.data   = cred.enc_part.cipher.data;
 102     } else {
 103         /* Try both subkey and session key.
 104          *
 105          * RFC4120 claims we should use the session key, but Heimdal
 106          * before 0.8 used the remote subkey if it was send in the
 107          * auth_context.
 108          */
 109
 110         if (auth_context->remote_subkey) {
 111             ret = krb5_crypto_init(context, auth_context->remote_subkey,
 112                                    0, &crypto);
 113             if (ret)
 114                 goto out;
 115
 116             ret = krb5_decrypt_EncryptedData(context,
 117                                              crypto,
 118                                              KRB5_KU_KRB_CRED,
 119                                              &cred.enc_part,
 120                                              &enc_krb_cred_part_data);
 121
 122             krb5_crypto_destroy(context, crypto);
 123         }
 124
 125         /*
 126          * If there was not subkey, or we failed using subkey,
 127          * retry using the session key
 128          */
 129         if (auth_context->remote_subkey == NULL || ret == KRB5KRB_AP_ERR_BAD_INTEGRITY)
 130         {
 131
 132             ret = krb5_crypto_init(context, auth_context->keyblock,
 133                                    0, &crypto);
 134
 135             if (ret)
 136                 goto out;
 137
 138             ret = krb5_decrypt_EncryptedData(context,
 139                                              crypto,
 140                                              KRB5_KU_KRB_CRED,
 141                                              &cred.enc_part,
 142                                              &enc_krb_cred_part_data);
 143
 144             krb5_crypto_destroy(context, crypto);
 145         }
 146         if (ret)
 147             goto out;
 148     }
 149
 150     ret = decode_EncKrbCredPart(enc_krb_cred_part_data.data,
 151                                 enc_krb_cred_part_data.length,
 152                                 &enc_krb_cred_part,
 153                                 &len);
 154     if (enc_krb_cred_part_data.data != cred.enc_part.cipher.data)
 155         krb5_data_free(&enc_krb_cred_part_data);
 156     if (ret) {
 157         krb5_set_error_message(context, ret,
 158                                N_("Failed to decode "
 159                                   "encrypte credential part", ""));
 160         goto out;
 161     }
 162
 163     /* check sender address */
 164
 165     if (enc_krb_cred_part.s_address
 166         && auth_context->remote_address
 167         && auth_context->remote_port) {
 168         krb5_address *a;
 169
 170         ret = krb5_make_addrport (context, &a,
 171                                   auth_context->remote_address,
 172                                   auth_context->remote_port);
 173         if (ret)
 174             goto out;
 175
 176
 177         ret = compare_addrs(context, a, enc_krb_cred_part.s_address,
 178                             N_("sender address is wrong "
 179                                "in received creds", ""));
 180         krb5_free_address(context, a);
 181         free(a);
 182         if(ret)
 183             goto out;
 184     }
 185
 186     /* check receiver address */
 187
 188     if (enc_krb_cred_part.r_address
 189         && auth_context->local_address) {
 190         if(auth_context->local_port &&
 191            enc_krb_cred_part.r_address->addr_type == KRB5_ADDRESS_ADDRPORT) {
 192             krb5_address *a;
 193             ret = krb5_make_addrport (context, &a,
 194                                       auth_context->local_address,
 195                                       auth_context->local_port);
 196             if (ret)
 197                 goto out;
 198
 199             ret = compare_addrs(context, a, enc_krb_cred_part.r_address,
 200                                 N_("receiver address is wrong "
 201                                    "in received creds", ""));
 202             krb5_free_address(context, a);
 203             free(a);
 204             if(ret)
 205                 goto out;
 206         } else {
 207             ret = compare_addrs(context, auth_context->local_address,
 208                                 enc_krb_cred_part.r_address,
 209                                 N_("receiver address is wrong "
 210                                    "in received creds", ""));
 211             if(ret)
 212                 goto out;
 213         }
 214     }
 215
 216     /* check timestamp */
 217     if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_TIME) {
 218         krb5_timestamp sec;
 219
 220         krb5_timeofday (context, &sec);
 221
 222         if (enc_krb_cred_part.timestamp == NULL ||
 223             enc_krb_cred_part.usec      == NULL ||
 224             abs(*enc_krb_cred_part.timestamp - sec)
 225             > context->max_skew) {
 226             krb5_clear_error_message (context);
 227             ret = KRB5KRB_AP_ERR_SKEW;
 228             goto out;
 229         }
 230     }
 231
 232     if ((auth_context->flags &
 233          (KRB5_AUTH_CONTEXT_RET_TIME | KRB5_AUTH_CONTEXT_RET_SEQUENCE))) {
 234         /* if these fields are not present in the cred-part, silently
 235            return zero */
 236         memset(outdata, 0, sizeof(*outdata));
 237         if(enc_krb_cred_part.timestamp)
 238             outdata->timestamp = *enc_krb_cred_part.timestamp;
 239         if(enc_krb_cred_part.usec)
 240             outdata->usec = *enc_krb_cred_part.usec;
 241         if(enc_krb_cred_part.nonce)
 242             outdata->seq = *enc_krb_cred_part.nonce;
 243     }
 244
 245     /* Convert to NULL terminated list of creds */
 246
 247     *ret_creds = calloc(enc_krb_cred_part.ticket_info.len + 1,
 248                         sizeof(**ret_creds));
 249
 250     if (*ret_creds == NULL) {
 251         ret = ENOMEM;
 252         krb5_set_error_message(context, ret,
 253                                N_("malloc: out of memory", ""));
 254         goto out;
 255     }
 256
 257     for (i = 0; i < enc_krb_cred_part.ticket_info.len; ++i) {
 258         KrbCredInfo *kci = &enc_krb_cred_part.ticket_info.val[i];
 259         krb5_creds *creds;
 260
 261         creds = calloc(1, sizeof(*creds));
 262         if(creds == NULL) {
 263             ret = ENOMEM;
 264             krb5_set_error_message(context, ret,
 265                                    N_("malloc: out of memory", ""));
 266             goto out;
 267         }
 268
 269         ASN1_MALLOC_ENCODE(Ticket, creds->ticket.data, creds->ticket.length,
 270                            &cred.tickets.val[i], &len, ret);
 271         if (ret) {
 272             free(creds);
 273             goto out;
 274         }
 275         if(creds->ticket.length != len)
 276             krb5_abortx(context, "internal error in ASN.1 encoder");
 277         copy_EncryptionKey (&kci->key, &creds->session);
 278         if (kci->prealm && kci->pname)
 279             _krb5_principalname2krb5_principal (context,
 280                                                 &creds->client,
 281                                                 *kci->pname,
 282                                                 *kci->prealm);
 283         if (kci->flags)
 284             creds->flags.b = *kci->flags;
 285         if (kci->authtime)
 286             creds->times.authtime = *kci->authtime;
 287         if (kci->starttime)
 288             creds->times.starttime = *kci->starttime;
 289         if (kci->endtime)
 290             creds->times.endtime = *kci->endtime;
 291         if (kci->renew_till)
 292             creds->times.renew_till = *kci->renew_till;
 293         if (kci->srealm && kci->sname)
 294             _krb5_principalname2krb5_principal (context,
 295                                                 &creds->server,
 296                                                 *kci->sname,
 297                                                 *kci->srealm);
 298         if (kci->caddr)
 299             krb5_copy_addresses (context,
 300                                  kci->caddr,
 301                                  &creds->addresses);
 302
 303         (*ret_creds)[i] = creds;
 304
 305     }
 306     (*ret_creds)[i] = NULL;
 307
 308     free_KRB_CRED (&cred);
 309     free_EncKrbCredPart(&enc_krb_cred_part);
 310
 311     return 0;
 312
 313   out:
 314     free_EncKrbCredPart(&enc_krb_cred_part);
 315     free_KRB_CRED (&cred);
 316     if(*ret_creds) {
 317         for(i = 0; (*ret_creds)[i]; i++)
 318             krb5_free_creds(context, (*ret_creds)[i]);
 319         free(*ret_creds);
 320         *ret_creds = NULL;
 321     }
 322     return ret;
 323 }
 324
 325 krb5_error_code KRB5_LIB_FUNCTION
 326 krb5_rd_cred2 (krb5_context      context,
 327                krb5_auth_context auth_context,
 328                krb5_ccache       ccache,
 329                krb5_data         *in_data)
 330 {
 331     krb5_error_code ret;
 332     krb5_creds **creds;
 333     int i;
 334
 335     ret = krb5_rd_cred(context, auth_context, in_data, &creds, NULL);
 336     if(ret)
 337         return ret;
 338
 339     /* Store the creds in the ccache */
 340
 341     for(i = 0; creds && creds[i]; i++) {
 342         krb5_cc_store_cred(context, ccache, creds[i]);
 343         krb5_free_creds(context, creds[i]);
 344     }
 345     free(creds);
 346     return 0;
 347 }