lib/krb5/get_addrs.c

   1 /*
   2  * Copyright (c) 1997 - 2002 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 #ifdef __osf__
  37 /* hate */
  38 struct rtentry;
  39 struct mbuf;
  40 #endif
  41 #ifdef HAVE_NET_IF_H
  42 #include <net/if.h>
  43 #endif
  44 #include <ifaddrs.h>
  45
  46 static krb5_error_code
  47 gethostname_fallback (krb5_context context, krb5_addresses *res)
  48 {
  49     krb5_error_code ret;
  50     char hostname[MAXHOSTNAMELEN];
  51     struct hostent *hostent;
  52
  53     if (krb5_config_get_bool(context, NULL, "libdefaults", "block_dns",
  54             NULL)) {
  55         ret = ENXIO;
  56         krb5_set_error_message(context, ret,
  57             "DNS blocked in gethostname fallback");
  58         return ret;
  59     }
  60
  61     if (gethostname (hostname, sizeof(hostname))) {
  62         ret = errno;
  63         krb5_set_error_message(context, ret, "gethostname: %s", strerror(ret));
  64         return ret;
  65     }
  66     hostent = roken_gethostbyname (hostname);
  67     if (hostent == NULL) {
  68         ret = errno;
  69         krb5_set_error_message (context, ret, "gethostbyname %s: %s",
  70                                 hostname, strerror(ret));
  71         return ret;
  72     }
  73     res->len = 1;
  74     res->val = malloc (sizeof(*res->val));
  75     if (res->val == NULL)
  76         return krb5_enomem(context);
  77     res->val[0].addr_type = hostent->h_addrtype;
  78     res->val[0].address.data = NULL;
  79     res->val[0].address.length = 0;
  80     ret = krb5_data_copy (&res->val[0].address,
  81                           hostent->h_addr,
  82                           hostent->h_length);
  83     if (ret) {
  84         free (res->val);
  85         return ret;
  86     }
  87     return 0;
  88 }
  89
  90 enum {
  91     LOOP            = 1,        /* do include loopback addrs */
  92     LOOP_IF_NONE    = 2,        /* include loopback addrs if no others */
  93     EXTRA_ADDRESSES = 4,        /* include extra addresses */
  94     SCAN_INTERFACES = 8         /* scan interfaces for addresses */
  95 };
  96
  97 /*
  98  * Try to figure out the addresses of all configured interfaces with a
  99  * lot of magic ioctls.
 100  */
 101
 102 static krb5_error_code
 103 find_all_addresses (krb5_context context, krb5_addresses *res, int flags)
 104 {
 105     struct sockaddr sa_zero;
 106     struct ifaddrs *ifa0, *ifa;
 107     krb5_error_code ret = ENXIO;
 108     unsigned int num, idx;
 109     krb5_addresses ignore_addresses;
 110
 111     if (getifaddrs(&ifa0) == -1) {
 112         ret = errno;
 113         krb5_set_error_message(context, ret, "getifaddrs: %s", strerror(ret));
 114         return (ret);
 115     }
 116
 117     memset(&sa_zero, 0, sizeof(sa_zero));
 118
 119     /* First, count all the ifaddrs. */
 120     for (ifa = ifa0, num = 0; ifa != NULL; ifa = ifa->ifa_next, num++)
 121         /* nothing */;
 122
 123     if (num == 0) {
 124         freeifaddrs(ifa0);
 125         krb5_set_error_message(context, ENXIO, N_("no addresses found", ""));
 126         return (ENXIO);
 127     }
 128
 129     if (flags & EXTRA_ADDRESSES) {
 130         /* we'll remove the addresses we don't care about */
 131         ret = krb5_get_ignore_addresses(context, &ignore_addresses);
 132         if(ret)
 133             return ret;
 134     }
 135
 136     /* Allocate storage for them. */
 137     res->val = calloc(num, sizeof(*res->val));
 138     if (res->val == NULL) {
 139         if (flags & EXTRA_ADDRESSES)
 140             krb5_free_addresses(context, &ignore_addresses);
 141         freeifaddrs(ifa0);
 142         return krb5_enomem(context);
 143     }
 144
 145     /* Now traverse the list. */
 146     for (ifa = ifa0, idx = 0; ifa != NULL; ifa = ifa->ifa_next) {
 147         if ((ifa->ifa_flags & IFF_UP) == 0)
 148             continue;
 149         if (ifa->ifa_addr == NULL)
 150             continue;
 151         if (memcmp(ifa->ifa_addr, &sa_zero, sizeof(sa_zero)) == 0)
 152             continue;
 153         if (krb5_sockaddr_uninteresting(ifa->ifa_addr))
 154             continue;
 155         if (krb5_sockaddr_is_loopback(ifa->ifa_addr) && (flags & LOOP) == 0)
 156             /* We'll deal with the LOOP_IF_NONE case later. */
 157             continue;
 158
 159         ret = krb5_sockaddr2address(context, ifa->ifa_addr, &res->val[idx]);
 160         if (ret) {
 161             /*
 162              * The most likely error here is going to be "Program
 163              * lacks support for address type".  This is no big
 164              * deal -- just continue, and we'll listen on the
 165              * addresses who's type we *do* support.
 166              */
 167             continue;
 168         }
 169         /* possibly skip this address? */
 170         if((flags & EXTRA_ADDRESSES) &&
 171            krb5_address_search(context, &res->val[idx], &ignore_addresses)) {
 172             krb5_free_address(context, &res->val[idx]);
 173             flags &= ~LOOP_IF_NONE; /* we actually found an address,
 174                                        so don't add any loop-back
 175                                        addresses */
 176             continue;
 177         }
 178
 179         idx++;
 180     }
 181
 182     /*
 183      * If no addresses were found, and LOOP_IF_NONE is set, then find
 184      * the loopback addresses and add them to our list.
 185      */
 186     if ((flags & LOOP_IF_NONE) != 0 && idx == 0) {
 187         for (ifa = ifa0; ifa != NULL; ifa = ifa->ifa_next) {
 188             if ((ifa->ifa_flags & IFF_UP) == 0)
 189                 continue;
 190             if (ifa->ifa_addr == NULL)
 191                 continue;
 192             if (memcmp(ifa->ifa_addr, &sa_zero, sizeof(sa_zero)) == 0)
 193                 continue;
 194             if (krb5_sockaddr_uninteresting(ifa->ifa_addr))
 195                 continue;
 196             if (!krb5_sockaddr_is_loopback(ifa->ifa_addr))
 197                 continue;
 198             if ((ifa->ifa_flags & IFF_LOOPBACK) == 0)
 199                 /* Presumably loopback addrs are only used on loopback ifs! */
 200                 continue;
 201             ret = krb5_sockaddr2address(context,
 202                                         ifa->ifa_addr, &res->val[idx]);
 203             if (ret)
 204                 continue; /* We don't consider this failure fatal */
 205             if((flags & EXTRA_ADDRESSES) &&
 206                krb5_address_search(context, &res->val[idx],
 207                                    &ignore_addresses)) {
 208                 krb5_free_address(context, &res->val[idx]);
 209                 continue;
 210             }
 211             idx++;
 212         }
 213     }
 214
 215     if (flags & EXTRA_ADDRESSES)
 216         krb5_free_addresses(context, &ignore_addresses);
 217     freeifaddrs(ifa0);
 218     if (ret) {
 219         free(res->val);
 220         res->val = NULL;
 221     } else
 222         res->len = idx;        /* Now a count. */
 223     return (ret);
 224 }
 225
 226 static krb5_error_code
 227 get_addrs_int (krb5_context context, krb5_addresses *res, int flags)
 228 {
 229     krb5_error_code ret = -1;
 230
 231     res->len = 0;
 232     res->val = NULL;
 233
 234     if (flags & SCAN_INTERFACES) {
 235         ret = find_all_addresses (context, res, flags);
 236         if(ret || res->len == 0)
 237             ret = gethostname_fallback (context, res);
 238     } else {
 239         ret = 0;
 240     }
 241
 242     if(ret == 0 && (flags & EXTRA_ADDRESSES)) {
 243         krb5_addresses a;
 244         /* append user specified addresses */
 245         ret = krb5_get_extra_addresses(context, &a);
 246         if(ret) {
 247             krb5_free_addresses(context, res);
 248             return ret;
 249         }
 250         ret = krb5_append_addresses(context, res, &a);
 251         if(ret) {
 252             krb5_free_addresses(context, res);
 253             return ret;
 254         }
 255         krb5_free_addresses(context, &a);
 256     }
 257     if(res->len == 0) {
 258         free(res->val);
 259         res->val = NULL;
 260     }
 261     return ret;
 262 }
 263
 264 /*
 265  * Try to get all addresses, but return the one corresponding to
 266  * `hostname' if we fail.
 267  *
 268  * Only include loopback address if there are no other.
 269  */
 270
 271 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
 272 krb5_get_all_client_addrs (krb5_context context, krb5_addresses *res)
 273 {
 274     int flags = LOOP_IF_NONE | EXTRA_ADDRESSES;
 275
 276     if (context->scan_interfaces)
 277         flags |= SCAN_INTERFACES;
 278
 279     return get_addrs_int (context, res, flags);
 280 }
 281
 282 /*
 283  * Try to get all local addresses that a server should listen to.
 284  * If that fails, we return the address corresponding to `hostname'.
 285  */
 286
 287 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
 288 krb5_get_all_server_addrs (krb5_context context, krb5_addresses *res)
 289 {
 290     return get_addrs_int (context, res, LOOP | SCAN_INTERFACES);
 291 }