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

   1 /*
   2  * Copyright (c) 1997 - 2004 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: get_for_creds.c 22504 2008-01-21 15:49:58Z lha $"
  37         "$NetBSD$");
  38
  39 static krb5_error_code
  40 add_addrs(krb5_context context,
  41           krb5_addresses *addr,
  42           struct addrinfo *ai)
  43 {
  44     krb5_error_code ret;
  45     unsigned n, i;
  46     void *tmp;
  47     struct addrinfo *a;
  48
  49     n = 0;
  50     for (a = ai; a != NULL; a = a->ai_next)
  51         ++n;
  52
  53     tmp = realloc(addr->val, (addr->len + n) * sizeof(*addr->val));
  54     if (tmp == NULL && (addr->len + n) != 0) {
  55         krb5_set_error_string(context, "malloc: out of memory");
  56         ret = ENOMEM;
  57         goto fail;
  58     }
  59     addr->val = tmp;
  60     for (i = addr->len; i < (addr->len + n); ++i) {
  61         addr->val[i].addr_type = 0;
  62         krb5_data_zero(&addr->val[i].address);
  63     }
  64     i = addr->len;
  65     for (a = ai; a != NULL; a = a->ai_next) {
  66         krb5_address ad;
  67
  68         ret = krb5_sockaddr2address (context, a->ai_addr, &ad);
  69         if (ret == 0) {
  70             if (krb5_address_search(context, &ad, addr))
  71                 krb5_free_address(context, &ad);
  72             else
  73                 addr->val[i++] = ad;
  74         }
  75         else if (ret == KRB5_PROG_ATYPE_NOSUPP)
  76             krb5_clear_error_string (context);
  77         else
  78             goto fail;
  79         addr->len = i;
  80     }
  81     return 0;
  82 fail:
  83     krb5_free_addresses (context, addr);
  84     return ret;
  85 }
  86
  87 /**
  88  * Forward credentials for client to host hostname , making them
  89  * forwardable if forwardable, and returning the blob of data to sent
  90  * in out_data.  If hostname == NULL, pick it from server.
  91  *
  92  * @param context A kerberos 5 context.
  93  * @param auth_context the auth context with the key to encrypt the out_data.
  94  * @param hostname the host to forward the tickets too.
  95  * @param client the client to delegate from.
  96  * @param server the server to delegate the credential too.
  97  * @param ccache credential cache to use.
  98  * @param forwardable make the forwarded ticket forwabledable.
  99  * @param out_data the resulting credential.
 100  *
 101  * @return Return an error code or 0.
 102  *
 103  * @ingroup krb5_credential
 104  */
 105
 106 krb5_error_code KRB5_LIB_FUNCTION
 107 krb5_fwd_tgt_creds (krb5_context        context,
 108                     krb5_auth_context   auth_context,
 109                     const char          *hostname,
 110                     krb5_principal      client,
 111                     krb5_principal      server,
 112                     krb5_ccache         ccache,
 113                     int                 forwardable,
 114                     krb5_data           *out_data)
 115 {
 116     krb5_flags flags = 0;
 117     krb5_creds creds;
 118     krb5_error_code ret;
 119     krb5_const_realm client_realm;
 120
 121     flags |= KDC_OPT_FORWARDED;
 122
 123     if (forwardable)
 124         flags |= KDC_OPT_FORWARDABLE;
 125
 126     if (hostname == NULL &&
 127         krb5_principal_get_type(context, server) == KRB5_NT_SRV_HST) {
 128         const char *inst = krb5_principal_get_comp_string(context, server, 0);
 129         const char *host = krb5_principal_get_comp_string(context, server, 1);
 130
 131         if (inst != NULL &&
 132             strcmp(inst, "host") == 0 &&
 133             host != NULL &&
 134             krb5_principal_get_comp_string(context, server, 2) == NULL)
 135             hostname = host;
 136     }
 137
 138     client_realm = krb5_principal_get_realm(context, client);
 139
 140     memset (&creds, 0, sizeof(creds));
 141     creds.client = client;
 142
 143     ret = krb5_build_principal(context,
 144                                &creds.server,
 145                                strlen(client_realm),
 146                                client_realm,
 147                                KRB5_TGS_NAME,
 148                                client_realm,
 149                                NULL);
 150     if (ret)
 151         return ret;
 152
 153     ret = krb5_get_forwarded_creds (context,
 154                                     auth_context,
 155                                     ccache,
 156                                     flags,
 157                                     hostname,
 158                                     &creds,
 159                                     out_data);
 160     return ret;
 161 }
 162
 163 /**
 164  * Gets tickets forwarded to hostname. If the tickets that are
 165  * forwarded are address-less, the forwarded tickets will also be
 166  * address-less.
 167  *
 168  * If the ticket have any address, hostname will be used for figure
 169  * out the address to forward the ticket too. This since this might
 170  * use DNS, its insecure and also doesn't represent configured all
 171  * addresses of the host. For example, the host might have two
 172  * adresses, one IPv4 and one IPv6 address where the later is not
 173  * published in DNS. This IPv6 address might be used communications
 174  * and thus the resulting ticket useless.
 175  *
 176  * @param context A kerberos 5 context.
 177  * @param auth_context the auth context with the key to encrypt the out_data.
 178  * @param ccache credential cache to use
 179  * @param flags the flags to control the resulting ticket flags
 180  * @param hostname the host to forward the tickets too.
 181  * @param in_creds the in client and server ticket names.  The client
 182  * and server components forwarded to the remote host.
 183  * @param out_data the resulting credential.
 184  *
 185  * @return Return an error code or 0.
 186  *
 187  * @ingroup krb5_credential
 188  */
 189
 190 krb5_error_code KRB5_LIB_FUNCTION
 191 krb5_get_forwarded_creds (krb5_context      context,
 192                           krb5_auth_context auth_context,
 193                           krb5_ccache       ccache,
 194                           krb5_flags        flags,
 195                           const char        *hostname,
 196                           krb5_creds        *in_creds,
 197                           krb5_data         *out_data)
 198 {
 199     krb5_error_code ret;
 200     krb5_creds *out_creds;
 201     krb5_addresses addrs, *paddrs;
 202     KRB_CRED cred;
 203     KrbCredInfo *krb_cred_info;
 204     EncKrbCredPart enc_krb_cred_part;
 205     size_t len;
 206     unsigned char *buf;
 207     size_t buf_size;
 208     krb5_kdc_flags kdc_flags;
 209     krb5_crypto crypto;
 210     struct addrinfo *ai;
 211     int save_errno;
 212     krb5_creds *ticket;
 213
 214     paddrs = NULL;
 215     addrs.len = 0;
 216     addrs.val = NULL;
 217
 218     ret = krb5_get_credentials(context, 0, ccache, in_creds, &ticket);
 219     if(ret == 0) {
 220         if (ticket->addresses.len)
 221             paddrs = &addrs;
 222         krb5_free_creds (context, ticket);
 223     } else {
 224         krb5_boolean noaddr;
 225         krb5_appdefault_boolean(context, NULL,
 226                                 krb5_principal_get_realm(context,
 227                                                          in_creds->client),
 228                                 "no-addresses", KRB5_ADDRESSLESS_DEFAULT,
 229                                 &noaddr);
 230         if (!noaddr)
 231             paddrs = &addrs;
 232     }
 233
 234     /*
 235      * If tickets have addresses, get the address of the remote host.
 236      */
 237
 238     if (paddrs != NULL) {
 239
 240         ret = getaddrinfo (hostname, NULL, NULL, &ai);
 241         if (ret) {
 242             save_errno = errno;
 243             krb5_set_error_string(context, "resolving %s: %s",
 244                                   hostname, gai_strerror(ret));
 245             return krb5_eai_to_heim_errno(ret, save_errno);
 246         }
 247
 248         ret = add_addrs (context, &addrs, ai);
 249         freeaddrinfo (ai);
 250         if (ret)
 251             return ret;
 252     }
 253
 254     kdc_flags.b = int2KDCOptions(flags);
 255
 256     ret = krb5_get_kdc_cred (context,
 257                              ccache,
 258                              kdc_flags,
 259                              paddrs,
 260                              NULL,
 261                              in_creds,
 262                              &out_creds);
 263     krb5_free_addresses (context, &addrs);
 264     if (ret)
 265         return ret;
 266
 267     memset (&cred, 0, sizeof(cred));
 268     cred.pvno = 5;
 269     cred.msg_type = krb_cred;
 270     ALLOC_SEQ(&cred.tickets, 1);
 271     if (cred.tickets.val == NULL) {
 272         ret = ENOMEM;
 273         krb5_set_error_string(context, "malloc: out of memory");
 274         goto out2;
 275     }
 276     ret = decode_Ticket(out_creds->ticket.data,
 277                         out_creds->ticket.length,
 278                         cred.tickets.val, &len);
 279     if (ret)
 280         goto out3;
 281
 282     memset (&enc_krb_cred_part, 0, sizeof(enc_krb_cred_part));
 283     ALLOC_SEQ(&enc_krb_cred_part.ticket_info, 1);
 284     if (enc_krb_cred_part.ticket_info.val == NULL) {
 285         ret = ENOMEM;
 286         krb5_set_error_string(context, "malloc: out of memory");
 287         goto out4;
 288     }
 289
 290     if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_TIME) {
 291         krb5_timestamp sec;
 292         int32_t usec;
 293
 294         krb5_us_timeofday (context, &sec, &usec);
 295
 296         ALLOC(enc_krb_cred_part.timestamp, 1);
 297         if (enc_krb_cred_part.timestamp == NULL) {
 298             ret = ENOMEM;
 299             krb5_set_error_string(context, "malloc: out of memory");
 300             goto out4;
 301         }
 302         *enc_krb_cred_part.timestamp = sec;
 303         ALLOC(enc_krb_cred_part.usec, 1);
 304         if (enc_krb_cred_part.usec == NULL) {
 305             ret = ENOMEM;
 306             krb5_set_error_string(context, "malloc: out of memory");
 307             goto out4;
 308         }
 309         *enc_krb_cred_part.usec      = usec;
 310     } else {
 311         enc_krb_cred_part.timestamp = NULL;
 312         enc_krb_cred_part.usec = NULL;
 313     }
 314
 315     if (auth_context->local_address && auth_context->local_port && paddrs) {
 316
 317         ret = krb5_make_addrport (context,
 318                                   &enc_krb_cred_part.s_address,
 319                                   auth_context->local_address,
 320                                   auth_context->local_port);
 321         if (ret)
 322             goto out4;
 323     }
 324
 325     if (auth_context->remote_address) {
 326         if (auth_context->remote_port) {
 327             krb5_boolean noaddr;
 328             krb5_const_realm srealm;
 329
 330             srealm = krb5_principal_get_realm(context, out_creds->server);
 331             /* Is this correct, and should we use the paddrs == NULL
 332                trick here as well? Having an address-less ticket may
 333                indicate that we don't know our own global address, but
 334                it does not necessary mean that we don't know the
 335                server's. */
 336             krb5_appdefault_boolean(context, NULL, srealm, "no-addresses",
 337                                     FALSE, &noaddr);
 338             if (!noaddr) {
 339                 ret = krb5_make_addrport (context,
 340                                           &enc_krb_cred_part.r_address,
 341                                           auth_context->remote_address,
 342                                           auth_context->remote_port);
 343                 if (ret)
 344                     goto out4;
 345             }
 346         } else {
 347             ALLOC(enc_krb_cred_part.r_address, 1);
 348             if (enc_krb_cred_part.r_address == NULL) {
 349                 ret = ENOMEM;
 350                 krb5_set_error_string(context, "malloc: out of memory");
 351                 goto out4;
 352             }
 353
 354             ret = krb5_copy_address (context, auth_context->remote_address,
 355                                      enc_krb_cred_part.r_address);
 356             if (ret)
 357                 goto out4;
 358         }
 359     }
 360
 361     /* fill ticket_info.val[0] */
 362
 363     enc_krb_cred_part.ticket_info.len = 1;
 364
 365     krb_cred_info = enc_krb_cred_part.ticket_info.val;
 366
 367     copy_EncryptionKey (&out_creds->session, &krb_cred_info->key);
 368     ALLOC(krb_cred_info->prealm, 1);
 369     copy_Realm (&out_creds->client->realm, krb_cred_info->prealm);
 370     ALLOC(krb_cred_info->pname, 1);
 371     copy_PrincipalName(&out_creds->client->name, krb_cred_info->pname);
 372     ALLOC(krb_cred_info->flags, 1);
 373     *krb_cred_info->flags          = out_creds->flags.b;
 374     ALLOC(krb_cred_info->authtime, 1);
 375     *krb_cred_info->authtime       = out_creds->times.authtime;
 376     ALLOC(krb_cred_info->starttime, 1);
 377     *krb_cred_info->starttime      = out_creds->times.starttime;
 378     ALLOC(krb_cred_info->endtime, 1);
 379     *krb_cred_info->endtime        = out_creds->times.endtime;
 380     ALLOC(krb_cred_info->renew_till, 1);
 381     *krb_cred_info->renew_till = out_creds->times.renew_till;
 382     ALLOC(krb_cred_info->srealm, 1);
 383     copy_Realm (&out_creds->server->realm, krb_cred_info->srealm);
 384     ALLOC(krb_cred_info->sname, 1);
 385     copy_PrincipalName (&out_creds->server->name, krb_cred_info->sname);
 386     ALLOC(krb_cred_info->caddr, 1);
 387     copy_HostAddresses (&out_creds->addresses, krb_cred_info->caddr);
 388
 389     krb5_free_creds (context, out_creds);
 390
 391     /* encode EncKrbCredPart */
 392
 393     ASN1_MALLOC_ENCODE(EncKrbCredPart, buf, buf_size,
 394                        &enc_krb_cred_part, &len, ret);
 395     free_EncKrbCredPart (&enc_krb_cred_part);
 396     if (ret) {
 397         free_KRB_CRED(&cred);
 398         return ret;
 399     }
 400     if(buf_size != len)
 401         krb5_abortx(context, "internal error in ASN.1 encoder");
 402
 403     /**
 404      * Some older of the MIT gssapi library used clear-text tickets
 405      * (warped inside AP-REQ encryption), use the krb5_auth_context
 406      * flag KRB5_AUTH_CONTEXT_CLEAR_FORWARDED_CRED to support those
 407      * tickets. The session key is used otherwise to encrypt the
 408      * forwarded ticket.
 409      */
 410
 411     if (auth_context->flags & KRB5_AUTH_CONTEXT_CLEAR_FORWARDED_CRED) {
 412         cred.enc_part.etype = ENCTYPE_NULL;
 413         cred.enc_part.kvno = NULL;
 414         cred.enc_part.cipher.data = buf;
 415         cred.enc_part.cipher.length = buf_size;
 416     } else {
 417         /*
 418          * Here older versions then 0.7.2 of Heimdal used the local or
 419          * remote subkey. That is wrong, the session key should be
 420          * used. Heimdal 0.7.2 and newer have code to try both in the
 421          * receiving end.
 422          */
 423
 424         ret = krb5_crypto_init(context, auth_context->keyblock, 0, &crypto);
 425         if (ret) {
 426             free(buf);
 427             free_KRB_CRED(&cred);
 428             return ret;
 429         }
 430         ret = krb5_encrypt_EncryptedData (context,
 431                                           crypto,
 432                                           KRB5_KU_KRB_CRED,
 433                                           buf,
 434                                           len,
 435                                           0,
 436                                           &cred.enc_part);
 437         free(buf);
 438         krb5_crypto_destroy(context, crypto);
 439         if (ret) {
 440             free_KRB_CRED(&cred);
 441             return ret;
 442         }
 443     }
 444
 445     ASN1_MALLOC_ENCODE(KRB_CRED, buf, buf_size, &cred, &len, ret);
 446     free_KRB_CRED (&cred);
 447     if (ret)
 448         return ret;
 449     if(buf_size != len)
 450         krb5_abortx(context, "internal error in ASN.1 encoder");
 451     out_data->length = len;
 452     out_data->data   = buf;
 453     return 0;
 454  out4:
 455     free_EncKrbCredPart(&enc_krb_cred_part);
 456  out3:
 457     free_KRB_CRED(&cred);
 458  out2:
 459     krb5_free_creds (context, out_creds);
 460     return ret;
 461 }