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 static krb5_error_code
  37 add_addrs(krb5_context context,
  38           krb5_addresses *addr,
  39           struct addrinfo *ai)
  40 {
  41     krb5_error_code ret;
  42     unsigned n, i;
  43     void *tmp;
  44     struct addrinfo *a;
  45
  46     n = 0;
  47     for (a = ai; a != NULL; a = a->ai_next)
  48         ++n;
  49
  50     tmp = realloc(addr->val, (addr->len + n) * sizeof(*addr->val));
  51     if (tmp == NULL && (addr->len + n) != 0) {
  52         ret = krb5_enomem(context);
  53         goto fail;
  54     }
  55     addr->val = tmp;
  56     for (i = addr->len; i < (addr->len + n); ++i) {
  57         addr->val[i].addr_type = 0;
  58         krb5_data_zero(&addr->val[i].address);
  59     }
  60     i = addr->len;
  61     for (a = ai; a != NULL; a = a->ai_next) {
  62         krb5_address ad;
  63
  64         ret = krb5_sockaddr2address (context, a->ai_addr, &ad);
  65         if (ret == 0) {
  66             if (krb5_address_search(context, &ad, addr))
  67                 krb5_free_address(context, &ad);
  68             else
  69                 addr->val[i++] = ad;
  70         }
  71         else if (ret == KRB5_PROG_ATYPE_NOSUPP)
  72             krb5_clear_error_message (context);
  73         else
  74             goto fail;
  75         addr->len = i;
  76     }
  77     return 0;
  78 fail:
  79     krb5_free_addresses (context, addr);
  80     return ret;
  81 }
  82
  83 /**
  84  * Forward credentials for client to host hostname , making them
  85  * forwardable if forwardable, and returning the blob of data to sent
  86  * in out_data.  If hostname == NULL, pick it from server.
  87  *
  88  * @param context A kerberos 5 context.
  89  * @param auth_context the auth context with the key to encrypt the out_data.
  90  * @param hostname the host to forward the tickets too.
  91  * @param client the client to delegate from.
  92  * @param server the server to delegate the credential too.
  93  * @param ccache credential cache to use.
  94  * @param forwardable make the forwarded ticket forwabledable.
  95  * @param out_data the resulting credential.
  96  *
  97  * @return Return an error code or 0.
  98  *
  99  * @ingroup krb5_credential
 100  */
 101
 102 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
 103 krb5_fwd_tgt_creds (krb5_context        context,
 104                     krb5_auth_context   auth_context,
 105                     const char          *hostname,
 106                     krb5_principal      client,
 107                     krb5_principal      server,
 108                     krb5_ccache         ccache,
 109                     int                 forwardable,
 110                     krb5_data           *out_data)
 111 {
 112     krb5_flags flags = 0;
 113     krb5_creds creds;
 114     krb5_error_code ret;
 115     krb5_const_realm client_realm;
 116
 117     flags |= KDC_OPT_FORWARDED;
 118
 119     if (forwardable)
 120         flags |= KDC_OPT_FORWARDABLE;
 121
 122     if (hostname == NULL &&
 123         krb5_principal_get_type(context, server) == KRB5_NT_SRV_HST) {
 124         const char *inst = krb5_principal_get_comp_string(context, server, 0);
 125         const char *host = krb5_principal_get_comp_string(context, server, 1);
 126
 127         if (inst != NULL &&
 128             strcmp(inst, "host") == 0 &&
 129             host != NULL &&
 130             krb5_principal_get_comp_string(context, server, 2) == NULL)
 131             hostname = host;
 132     }
 133
 134     client_realm = krb5_principal_get_realm(context, client);
 135
 136     memset (&creds, 0, sizeof(creds));
 137     creds.client = client;
 138
 139     ret = krb5_make_principal(context,
 140                               &creds.server,
 141                               client_realm,
 142                               KRB5_TGS_NAME,
 143                               client_realm,
 144                               NULL);
 145     if (ret)
 146         return ret;
 147
 148     ret = krb5_get_forwarded_creds (context,
 149                                     auth_context,
 150                                     ccache,
 151                                     flags,
 152                                     hostname,
 153                                     &creds,
 154                                     out_data);
 155     return ret;
 156 }
 157
 158 /**
 159  * Gets tickets forwarded to hostname. If the tickets that are
 160  * forwarded are address-less, the forwarded tickets will also be
 161  * address-less.
 162  *
 163  * If the ticket have any address, hostname will be used for figure
 164  * out the address to forward the ticket too. This since this might
 165  * use DNS, its insecure and also doesn't represent configured all
 166  * addresses of the host. For example, the host might have two
 167  * adresses, one IPv4 and one IPv6 address where the later is not
 168  * published in DNS. This IPv6 address might be used communications
 169  * and thus the resulting ticket useless.
 170  *
 171  * @param context A kerberos 5 context.
 172  * @param auth_context the auth context with the key to encrypt the out_data.
 173  * @param ccache credential cache to use
 174  * @param flags the flags to control the resulting ticket flags
 175  * @param hostname the host to forward the tickets too.
 176  * @param in_creds the in client and server ticket names.  The client
 177  * and server components forwarded to the remote host.
 178  * @param out_data the resulting credential.
 179  *
 180  * @return Return an error code or 0.
 181  *
 182  * @ingroup krb5_credential
 183  */
 184
 185 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
 186 krb5_get_forwarded_creds (krb5_context      context,
 187                           krb5_auth_context auth_context,
 188                           krb5_ccache       ccache,
 189                           krb5_flags        flags,
 190                           const char        *hostname,
 191                           krb5_creds        *in_creds,
 192                           krb5_data         *out_data)
 193 {
 194     krb5_error_code ret;
 195     krb5_creds *out_creds;
 196     krb5_addresses addrs, *paddrs;
 197     KRB_CRED cred;
 198     KrbCredInfo *krb_cred_info;
 199     EncKrbCredPart enc_krb_cred_part;
 200     size_t len;
 201     unsigned char *buf;
 202     size_t buf_size;
 203     krb5_kdc_flags kdc_flags;
 204     krb5_crypto crypto;
 205     struct addrinfo *ai;
 206     krb5_creds *ticket;
 207
 208     paddrs = NULL;
 209     addrs.len = 0;
 210     addrs.val = NULL;
 211
 212     ret = krb5_get_credentials(context, 0, ccache, in_creds, &ticket);
 213     if(ret == 0) {
 214         if (ticket->addresses.len)
 215             paddrs = &addrs;
 216         krb5_free_creds (context, ticket);
 217     } else {
 218         krb5_boolean noaddr;
 219         krb5_appdefault_boolean(context, NULL,
 220                                 krb5_principal_get_realm(context,
 221                                                          in_creds->client),
 222                                 "no-addresses", KRB5_ADDRESSLESS_DEFAULT,
 223                                 &noaddr);
 224         if (!noaddr)
 225             paddrs = &addrs;
 226     }
 227
 228     /*
 229      * If tickets have addresses, get the address of the remote host.
 230      */
 231
 232     if (paddrs != NULL) {
 233
 234         ret = getaddrinfo (hostname, NULL, NULL, &ai);
 235         if (ret) {
 236             krb5_error_code ret2 = krb5_eai_to_heim_errno(ret, errno);
 237             krb5_set_error_message(context, ret2,
 238                                    N_("resolving host %s failed: %s",
 239                                       "hostname, error"),
 240                                   hostname, gai_strerror(ret));
 241             return ret2;
 242         }
 243
 244         ret = add_addrs (context, &addrs, ai);
 245         freeaddrinfo (ai);
 246         if (ret)
 247             return ret;
 248     }
 249
 250     kdc_flags.b = int2KDCOptions(flags);
 251
 252     ret = krb5_get_kdc_cred (context,
 253                              ccache,
 254                              kdc_flags,
 255                              paddrs,
 256                              NULL,
 257                              in_creds,
 258                              &out_creds);
 259     krb5_free_addresses (context, &addrs);
 260     if (ret)
 261         return ret;
 262
 263     memset (&cred, 0, sizeof(cred));
 264     cred.pvno = 5;
 265     cred.msg_type = krb_cred;
 266     ALLOC_SEQ(&cred.tickets, 1);
 267     if (cred.tickets.val == NULL) {
 268         ret = krb5_enomem(context);
 269         goto out2;
 270     }
 271     ret = decode_Ticket(out_creds->ticket.data,
 272                         out_creds->ticket.length,
 273                         cred.tickets.val, &len);
 274     if (ret)
 275         goto out3;
 276
 277     memset (&enc_krb_cred_part, 0, sizeof(enc_krb_cred_part));
 278     ALLOC_SEQ(&enc_krb_cred_part.ticket_info, 1);
 279     if (enc_krb_cred_part.ticket_info.val == NULL) {
 280         ret = krb5_enomem(context);
 281         goto out4;
 282     }
 283
 284     if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_TIME) {
 285         krb5_timestamp sec;
 286         int32_t usec;
 287
 288         krb5_us_timeofday (context, &sec, &usec);
 289
 290         ALLOC(enc_krb_cred_part.timestamp, 1);
 291         if (enc_krb_cred_part.timestamp == NULL) {
 292             ret = krb5_enomem(context);
 293             goto out4;
 294         }
 295         *enc_krb_cred_part.timestamp = sec;
 296         ALLOC(enc_krb_cred_part.usec, 1);
 297         if (enc_krb_cred_part.usec == NULL) {
 298             ret = krb5_enomem(context);
 299             goto out4;
 300         }
 301         *enc_krb_cred_part.usec      = usec;
 302     } else {
 303         enc_krb_cred_part.timestamp = NULL;
 304         enc_krb_cred_part.usec = NULL;
 305     }
 306
 307     if (auth_context->local_address && auth_context->local_port && paddrs) {
 308
 309         ret = krb5_make_addrport (context,
 310                                   &enc_krb_cred_part.s_address,
 311                                   auth_context->local_address,
 312                                   auth_context->local_port);
 313         if (ret)
 314             goto out4;
 315     }
 316
 317     if (auth_context->remote_address) {
 318         if (auth_context->remote_port) {
 319             krb5_boolean noaddr;
 320             krb5_const_realm srealm;
 321
 322             srealm = krb5_principal_get_realm(context, out_creds->server);
 323             /* Is this correct, and should we use the paddrs == NULL
 324                trick here as well? Having an address-less ticket may
 325                indicate that we don't know our own global address, but
 326                it does not necessary mean that we don't know the
 327                server's. */
 328             krb5_appdefault_boolean(context, NULL, srealm, "no-addresses",
 329                                     FALSE, &noaddr);
 330             if (!noaddr) {
 331                 ret = krb5_make_addrport (context,
 332                                           &enc_krb_cred_part.r_address,
 333                                           auth_context->remote_address,
 334                                           auth_context->remote_port);
 335                 if (ret)
 336                     goto out4;
 337             }
 338         } else {
 339             ALLOC(enc_krb_cred_part.r_address, 1);
 340             if (enc_krb_cred_part.r_address == NULL) {
 341                 ret = krb5_enomem(context);
 342                 goto out4;
 343             }
 344
 345             ret = krb5_copy_address (context, auth_context->remote_address,
 346                                      enc_krb_cred_part.r_address);
 347             if (ret)
 348                 goto out4;
 349         }
 350     }
 351
 352     /* fill ticket_info.val[0] */
 353
 354     enc_krb_cred_part.ticket_info.len = 1;
 355
 356     krb_cred_info = enc_krb_cred_part.ticket_info.val;
 357
 358     copy_EncryptionKey (&out_creds->session, &krb_cred_info->key);
 359     ALLOC(krb_cred_info->prealm, 1);
 360     copy_Realm (&out_creds->client->realm, krb_cred_info->prealm);
 361     ALLOC(krb_cred_info->pname, 1);
 362     copy_PrincipalName(&out_creds->client->name, krb_cred_info->pname);
 363     ALLOC(krb_cred_info->flags, 1);
 364     *krb_cred_info->flags          = out_creds->flags.b;
 365     ALLOC(krb_cred_info->authtime, 1);
 366     *krb_cred_info->authtime       = out_creds->times.authtime;
 367     ALLOC(krb_cred_info->starttime, 1);
 368     *krb_cred_info->starttime      = out_creds->times.starttime;
 369     ALLOC(krb_cred_info->endtime, 1);
 370     *krb_cred_info->endtime        = out_creds->times.endtime;
 371     ALLOC(krb_cred_info->renew_till, 1);
 372     *krb_cred_info->renew_till = out_creds->times.renew_till;
 373     ALLOC(krb_cred_info->srealm, 1);
 374     copy_Realm (&out_creds->server->realm, krb_cred_info->srealm);
 375     ALLOC(krb_cred_info->sname, 1);
 376     copy_PrincipalName (&out_creds->server->name, krb_cred_info->sname);
 377     ALLOC(krb_cred_info->caddr, 1);
 378     copy_HostAddresses (&out_creds->addresses, krb_cred_info->caddr);
 379
 380     krb5_free_creds (context, out_creds);
 381
 382     /* encode EncKrbCredPart */
 383
 384     ASN1_MALLOC_ENCODE(EncKrbCredPart, buf, buf_size,
 385                        &enc_krb_cred_part, &len, ret);
 386     free_EncKrbCredPart (&enc_krb_cred_part);
 387     if (ret) {
 388         free_KRB_CRED(&cred);
 389         return ret;
 390     }
 391     if(buf_size != len)
 392         krb5_abortx(context, "internal error in ASN.1 encoder");
 393
 394     /**
 395      * Some older of the MIT gssapi library used clear-text tickets
 396      * (warped inside AP-REQ encryption), use the krb5_auth_context
 397      * flag KRB5_AUTH_CONTEXT_CLEAR_FORWARDED_CRED to support those
 398      * tickets. The session key is used otherwise to encrypt the
 399      * forwarded ticket.
 400      */
 401
 402     if (auth_context->flags & KRB5_AUTH_CONTEXT_CLEAR_FORWARDED_CRED) {
 403         cred.enc_part.etype = KRB5_ENCTYPE_NULL;
 404         cred.enc_part.kvno = NULL;
 405         cred.enc_part.cipher.data = buf;
 406         cred.enc_part.cipher.length = buf_size;
 407     } else {
 408         /*
 409          * Here older versions then 0.7.2 of Heimdal used the local or
 410          * remote subkey. That is wrong, the session key should be
 411          * used. Heimdal 0.7.2 and newer have code to try both in the
 412          * receiving end.
 413          */
 414
 415         ret = krb5_crypto_init(context, auth_context->keyblock, 0, &crypto);
 416         if (ret) {
 417             free(buf);
 418             free_KRB_CRED(&cred);
 419             return ret;
 420         }
 421         ret = krb5_encrypt_EncryptedData (context,
 422                                           crypto,
 423                                           KRB5_KU_KRB_CRED,
 424                                           buf,
 425                                           len,
 426                                           0,
 427                                           &cred.enc_part);
 428         free(buf);
 429         krb5_crypto_destroy(context, crypto);
 430         if (ret) {
 431             free_KRB_CRED(&cred);
 432             return ret;
 433         }
 434     }
 435
 436     ASN1_MALLOC_ENCODE(KRB_CRED, buf, buf_size, &cred, &len, ret);
 437     free_KRB_CRED (&cred);
 438     if (ret)
 439         return ret;
 440     if(buf_size != len)
 441         krb5_abortx(context, "internal error in ASN.1 encoder");
 442     out_data->length = len;
 443     out_data->data   = buf;
 444     return 0;
 445  out4:
 446     free_EncKrbCredPart(&enc_krb_cred_part);
 447  out3:
 448     free_KRB_CRED(&cred);
 449  out2:
 450     krb5_free_creds (context, out_creds);
 451     return ret;
 452 }