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