1 /*        $NetBSD: get_addrs.c,v 1.2 2017/01/28 21:31:49 christos Exp $         */
2 
3 /*
4  * Copyright (c) 1997 - 2002 Kungliga Tekniska Högskolan
5  * (Royal Institute of Technology, Stockholm, Sweden).
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  *
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  *
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  *
19  * 3. Neither the name of the Institute nor the names of its contributors
20  *    may be used to endorse or promote products derived from this software
21  *    without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  */
35 
36 #include "krb5_locl.h"
37 
38 #ifdef __osf__
39 /* hate */
40 struct rtentry;
41 struct mbuf;
42 #endif
43 #ifdef HAVE_NET_IF_H
44 #include <net/if.h>
45 #endif
46 #include <ifaddrs.h>
47 
48 static krb5_error_code
gethostname_fallback(krb5_context context,krb5_addresses * res)49 gethostname_fallback (krb5_context context, krb5_addresses *res)
50 {
51     krb5_error_code ret;
52     char hostname[MAXHOSTNAMELEN];
53     struct hostent *hostent;
54 
55     if (gethostname (hostname, sizeof(hostname))) {
56           ret = errno;
57           krb5_set_error_message(context, ret, "gethostname: %s", strerror(ret));
58           return ret;
59     }
60     hostent = roken_gethostbyname (hostname);
61     if (hostent == NULL) {
62           ret = errno;
63           krb5_set_error_message (context, ret, "gethostbyname %s: %s",
64                                         hostname, strerror(ret));
65           return ret;
66     }
67     res->len = 1;
68     res->val = malloc (sizeof(*res->val));
69     if (res->val == NULL)
70           return krb5_enomem(context);
71     res->val[0].addr_type = hostent->h_addrtype;
72     res->val[0].address.data = NULL;
73     res->val[0].address.length = 0;
74     ret = krb5_data_copy (&res->val[0].address,
75                                 hostent->h_addr,
76                                 hostent->h_length);
77     if (ret) {
78           free (res->val);
79           return ret;
80     }
81     return 0;
82 }
83 
84 enum {
85     LOOP            = 1,      /* do include loopback addrs */
86     LOOP_IF_NONE    = 2,      /* include loopback addrs if no others */
87     EXTRA_ADDRESSES = 4,      /* include extra addresses */
88     SCAN_INTERFACES = 8                 /* scan interfaces for addresses */
89 };
90 
91 /*
92  * Try to figure out the addresses of all configured interfaces with a
93  * lot of magic ioctls.
94  */
95 
96 static krb5_error_code
find_all_addresses(krb5_context context,krb5_addresses * res,int flags)97 find_all_addresses (krb5_context context, krb5_addresses *res, int flags)
98 {
99     struct sockaddr sa_zero;
100     struct ifaddrs *ifa0, *ifa;
101     krb5_error_code ret = ENXIO;
102     unsigned int num, idx;
103     krb5_addresses ignore_addresses;
104 
105     if (getifaddrs(&ifa0) == -1) {
106           ret = errno;
107           krb5_set_error_message(context, ret, "getifaddrs: %s", strerror(ret));
108           return (ret);
109     }
110 
111     memset(&sa_zero, 0, sizeof(sa_zero));
112 
113     /* First, count all the ifaddrs. */
114     for (ifa = ifa0, num = 0; ifa != NULL; ifa = ifa->ifa_next, num++)
115           /* nothing */;
116 
117     if (num == 0) {
118           freeifaddrs(ifa0);
119           krb5_set_error_message(context, ENXIO, N_("no addresses found", ""));
120           return (ENXIO);
121     }
122 
123     if (flags & EXTRA_ADDRESSES) {
124           /* we'll remove the addresses we don't care about */
125           ret = krb5_get_ignore_addresses(context, &ignore_addresses);
126           if(ret)
127               return ret;
128     }
129 
130     /* Allocate storage for them. */
131     res->val = calloc(num, sizeof(*res->val));
132     if (res->val == NULL) {
133           if (flags & EXTRA_ADDRESSES)
134               krb5_free_addresses(context, &ignore_addresses);
135           freeifaddrs(ifa0);
136           return krb5_enomem(context);
137     }
138 
139     /* Now traverse the list. */
140     for (ifa = ifa0, idx = 0; ifa != NULL; ifa = ifa->ifa_next) {
141           if ((ifa->ifa_flags & IFF_UP) == 0)
142               continue;
143           if (ifa->ifa_addr == NULL)
144               continue;
145           if (memcmp(ifa->ifa_addr, &sa_zero, sizeof(sa_zero)) == 0)
146               continue;
147           if (krb5_sockaddr_uninteresting(ifa->ifa_addr))
148               continue;
149           if (krb5_sockaddr_is_loopback(ifa->ifa_addr) && (flags & LOOP) == 0)
150               /* We'll deal with the LOOP_IF_NONE case later. */
151               continue;
152 
153           ret = krb5_sockaddr2address(context, ifa->ifa_addr, &res->val[idx]);
154           if (ret) {
155               /*
156                * The most likely error here is going to be "Program
157                * lacks support for address type".  This is no big
158                * deal -- just continue, and we'll listen on the
159                * addresses who's type we *do* support.
160                */
161               continue;
162           }
163           /* possibly skip this address? */
164           if((flags & EXTRA_ADDRESSES) &&
165              krb5_address_search(context, &res->val[idx], &ignore_addresses)) {
166               krb5_free_address(context, &res->val[idx]);
167               flags &= ~LOOP_IF_NONE; /* we actually found an address,
168                                        so don't add any loop-back
169                                        addresses */
170               continue;
171           }
172 
173           idx++;
174     }
175 
176     /*
177      * If no addresses were found, and LOOP_IF_NONE is set, then find
178      * the loopback addresses and add them to our list.
179      */
180     if ((flags & LOOP_IF_NONE) != 0 && idx == 0) {
181           for (ifa = ifa0; ifa != NULL; ifa = ifa->ifa_next) {
182               if ((ifa->ifa_flags & IFF_UP) == 0)
183                     continue;
184               if (ifa->ifa_addr == NULL)
185                     continue;
186               if (memcmp(ifa->ifa_addr, &sa_zero, sizeof(sa_zero)) == 0)
187                     continue;
188               if (krb5_sockaddr_uninteresting(ifa->ifa_addr))
189                     continue;
190               if (!krb5_sockaddr_is_loopback(ifa->ifa_addr))
191                     continue;
192               if ((ifa->ifa_flags & IFF_LOOPBACK) == 0)
193                     /* Presumably loopback addrs are only used on loopback ifs! */
194                     continue;
195               ret = krb5_sockaddr2address(context,
196                                                   ifa->ifa_addr, &res->val[idx]);
197               if (ret)
198                     continue; /* We don't consider this failure fatal */
199               if((flags & EXTRA_ADDRESSES) &&
200                  krb5_address_search(context, &res->val[idx],
201                                            &ignore_addresses)) {
202                     krb5_free_address(context, &res->val[idx]);
203                     continue;
204               }
205               idx++;
206           }
207     }
208 
209     if (flags & EXTRA_ADDRESSES)
210           krb5_free_addresses(context, &ignore_addresses);
211     freeifaddrs(ifa0);
212     if (ret) {
213           free(res->val);
214           res->val = NULL;
215     } else
216           res->len = idx;        /* Now a count. */
217     return (ret);
218 }
219 
220 static krb5_error_code
get_addrs_int(krb5_context context,krb5_addresses * res,int flags)221 get_addrs_int (krb5_context context, krb5_addresses *res, int flags)
222 {
223     krb5_error_code ret = -1;
224 
225     res->len = 0;
226     res->val = NULL;
227 
228     if (flags & SCAN_INTERFACES) {
229           ret = find_all_addresses (context, res, flags);
230           if(ret || res->len == 0)
231               ret = gethostname_fallback (context, res);
232     } else {
233           ret = 0;
234     }
235 
236     if(ret == 0 && (flags & EXTRA_ADDRESSES)) {
237           krb5_addresses a;
238           /* append user specified addresses */
239           ret = krb5_get_extra_addresses(context, &a);
240           if(ret) {
241               krb5_free_addresses(context, res);
242               return ret;
243           }
244           ret = krb5_append_addresses(context, res, &a);
245           if(ret) {
246               krb5_free_addresses(context, res);
247               return ret;
248           }
249           krb5_free_addresses(context, &a);
250     }
251     if(res->len == 0) {
252           free(res->val);
253           res->val = NULL;
254     }
255     return ret;
256 }
257 
258 /*
259  * Try to get all addresses, but return the one corresponding to
260  * `hostname' if we fail.
261  *
262  * Only include loopback address if there are no other.
263  */
264 
265 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_get_all_client_addrs(krb5_context context,krb5_addresses * res)266 krb5_get_all_client_addrs (krb5_context context, krb5_addresses *res)
267 {
268     int flags = LOOP_IF_NONE | EXTRA_ADDRESSES;
269 
270     if (context->scan_interfaces)
271           flags |= SCAN_INTERFACES;
272 
273     return get_addrs_int (context, res, flags);
274 }
275 
276 /*
277  * Try to get all local addresses that a server should listen to.
278  * If that fails, we return the address corresponding to `hostname'.
279  */
280 
281 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_get_all_server_addrs(krb5_context context,krb5_addresses * res)282 krb5_get_all_server_addrs (krb5_context context, krb5_addresses *res)
283 {
284     return get_addrs_int (context, res, LOOP | SCAN_INTERFACES);
285 }
286