2 * Functions for looking up the remote name or addr of a socket.
4 * Copyright (C) 1992-2001 Andrew Tridgell <tridge@samba.org>
5 * Copyright (C) 2001, 2002 Martin Pool <mbp@samba.org>
6 * Copyright (C) 2002, 2003, 2004 Wayne Davison
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
18 * You should have received a copy of the GNU General Public License along
19 * with this program; if not, write to the Free Software Foundation, Inc.,
20 * 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.
24 * This file is now converted to use the new-style getaddrinfo()
25 * interface, which supports IPv6 but is also supported on recent
26 * IPv4-only machines. On systems that don't have that interface, we
27 * emulate it using the KAME implementation.
32 static const char default_name[] = "UNKNOWN";
37 * Return the IP addr of the client as a string
39 char *client_addr(int fd)
41 static char addr_buf[100];
42 static int initialised;
43 struct sockaddr_storage ss;
44 socklen_t length = sizeof ss;
52 if (am_server) { /* daemon over --rsh mode */
53 strlcpy(addr_buf, "0.0.0.0", sizeof addr_buf);
54 if ((ssh_info = getenv("SSH_CONNECTION")) != NULL
55 || (ssh_info = getenv("SSH_CLIENT")) != NULL
56 || (ssh_info = getenv("SSH2_CLIENT")) != NULL) {
57 strlcpy(addr_buf, ssh_info, sizeof addr_buf);
58 /* Truncate the value to just the IP address. */
59 if ((p = strchr(addr_buf, ' ')) != NULL)
63 client_sockaddr(fd, &ss, &length);
64 getnameinfo((struct sockaddr *)&ss, length,
65 addr_buf, sizeof addr_buf, NULL, 0, NI_NUMERICHOST);
72 static int get_sockaddr_family(const struct sockaddr_storage *ss)
74 return ((struct sockaddr *) ss)->sa_family;
79 * Return the DNS name of the client.
81 * The name is statically cached so that repeated lookups are quick,
82 * so there is a limit of one lookup per customer.
84 * If anything goes wrong, including the name->addr->name check, then
85 * we just use "UNKNOWN", so you can use that value in hosts allow
88 * After translation from sockaddr to name we do a forward lookup to
89 * make sure nobody is spoofing PTR records.
91 char *client_name(int fd)
93 static char name_buf[100];
94 static char port_buf[100];
95 static int initialised;
96 struct sockaddr_storage ss;
102 strlcpy(name_buf, default_name, sizeof name_buf);
105 memset(&ss, 0, sizeof ss);
107 if (am_server) { /* daemon over --rsh mode */
108 char *addr = client_addr(fd);
109 struct addrinfo hint, *answer;
112 memset(&hint, 0, sizeof hint);
114 #ifdef AI_NUMERICHOST
115 hint.ai_flags = AI_NUMERICHOST;
117 hint.ai_socktype = SOCK_STREAM;
119 if ((err = getaddrinfo(addr, NULL, &hint, &answer)) != 0) {
120 rprintf(FLOG, "malformed address %s: %s\n",
121 addr, gai_strerror(err));
125 switch (answer->ai_family) {
127 ss_len = sizeof (struct sockaddr_in);
128 memcpy(&ss, answer->ai_addr, ss_len);
132 ss_len = sizeof (struct sockaddr_in6);
133 memcpy(&ss, answer->ai_addr, ss_len);
137 exit_cleanup(RERR_SOCKETIO);
139 freeaddrinfo(answer);
142 client_sockaddr(fd, &ss, &ss_len);
145 if (lookup_name(fd, &ss, ss_len, name_buf, sizeof name_buf,
146 port_buf, sizeof port_buf) == 0)
147 check_name(fd, &ss, name_buf, sizeof name_buf);
155 * Get the sockaddr for the client.
157 * If it comes in as an ipv4 address mapped into IPv6 format then we
158 * convert it back to a regular IPv4.
160 void client_sockaddr(int fd,
161 struct sockaddr_storage *ss,
164 memset(ss, 0, sizeof *ss);
166 if (getpeername(fd, (struct sockaddr *) ss, ss_len)) {
167 /* FIXME: Can we really not continue? */
168 rsyserr(FLOG, errno, "getpeername on fd%d failed", fd);
169 exit_cleanup(RERR_SOCKETIO);
173 if (get_sockaddr_family(ss) == AF_INET6 &&
174 IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)ss)->sin6_addr)) {
175 /* OK, so ss is in the IPv6 family, but it is really
176 * an IPv4 address: something like
177 * "::ffff:10.130.1.2". If we use it as-is, then the
178 * reverse lookup might fail or perhaps something else
179 * bad might happen. So instead we convert it to an
180 * equivalent address in the IPv4 address family. */
181 struct sockaddr_in6 sin6;
182 struct sockaddr_in *sin;
184 memcpy(&sin6, ss, sizeof sin6);
185 sin = (struct sockaddr_in *)ss;
186 memset(sin, 0, sizeof *sin);
187 sin->sin_family = AF_INET;
188 *ss_len = sizeof (struct sockaddr_in);
189 #ifdef HAVE_SOCKADDR_IN_LEN
190 sin->sin_len = *ss_len;
192 sin->sin_port = sin6.sin6_port;
194 /* There is a macro to extract the mapped part
195 * (IN6_V4MAPPED_TO_SINADDR ?), but it does not seem
196 * to be present in the Linux headers. */
197 memcpy(&sin->sin_addr, &sin6.sin6_addr.s6_addr[12],
198 sizeof sin->sin_addr);
205 * Look up a name from @p ss into @p name_buf.
207 * @param fd file descriptor for client socket.
209 int lookup_name(int fd, const struct sockaddr_storage *ss,
211 char *name_buf, size_t name_buf_size,
212 char *port_buf, size_t port_buf_size)
217 name_err = getnameinfo((struct sockaddr *) ss, ss_len,
218 name_buf, name_buf_size,
219 port_buf, port_buf_size,
220 NI_NAMEREQD | NI_NUMERICSERV);
222 strlcpy(name_buf, default_name, name_buf_size);
223 rprintf(FLOG, "name lookup failed for %s: %s\n",
224 client_addr(fd), gai_strerror(name_err));
234 * Compare an addrinfo from the resolver to a sockinfo.
236 * Like strcmp, returns 0 for identical.
238 int compare_addrinfo_sockaddr(const struct addrinfo *ai,
239 const struct sockaddr_storage *ss)
241 int ss_family = get_sockaddr_family(ss);
242 const char fn[] = "compare_addrinfo_sockaddr";
244 if (ai->ai_family != ss_family) {
245 rprintf(FLOG, "%s: response family %d != %d\n",
246 fn, ai->ai_family, ss_family);
250 /* The comparison method depends on the particular AF. */
251 if (ss_family == AF_INET) {
252 const struct sockaddr_in *sin1, *sin2;
254 sin1 = (const struct sockaddr_in *) ss;
255 sin2 = (const struct sockaddr_in *) ai->ai_addr;
257 return memcmp(&sin1->sin_addr, &sin2->sin_addr,
258 sizeof sin1->sin_addr);
262 if (ss_family == AF_INET6) {
263 const struct sockaddr_in6 *sin1, *sin2;
265 sin1 = (const struct sockaddr_in6 *) ss;
266 sin2 = (const struct sockaddr_in6 *) ai->ai_addr;
268 if (ai->ai_addrlen < sizeof (struct sockaddr_in6)) {
269 rprintf(FLOG, "%s: too short sockaddr_in6; length=%d\n",
274 if (memcmp(&sin1->sin6_addr, &sin2->sin6_addr,
275 sizeof sin1->sin6_addr))
278 #ifdef HAVE_SOCKADDR_IN6_SCOPE_ID
279 if (sin1->sin6_scope_id != sin2->sin6_scope_id)
292 * Do a forward lookup on @p name_buf and make sure it corresponds to
293 * @p ss -- otherwise we may be being spoofed. If we suspect we are,
294 * then we don't abort the connection but just emit a warning, and
295 * change @p name_buf to be "UNKNOWN".
297 * We don't do anything with the service when checking the name,
298 * because it doesn't seem that it could be spoofed in any way, and
299 * getaddrinfo on random service names seems to cause problems on AIX.
301 int check_name(int fd,
302 const struct sockaddr_storage *ss,
303 char *name_buf, size_t name_buf_size)
305 struct addrinfo hints, *res, *res0;
307 int ss_family = get_sockaddr_family(ss);
309 memset(&hints, 0, sizeof hints);
310 hints.ai_family = ss_family;
311 hints.ai_flags = AI_CANONNAME;
312 hints.ai_socktype = SOCK_STREAM;
313 error = getaddrinfo(name_buf, NULL, &hints, &res0);
315 rprintf(FLOG, "forward name lookup for %s failed: %s\n",
316 name_buf, gai_strerror(error));
317 strlcpy(name_buf, default_name, name_buf_size);
321 /* Given all these results, we expect that one of them will be
322 * the same as ss. The comparison is a bit complicated. */
323 for (res = res0; res; res = res->ai_next) {
324 if (!compare_addrinfo_sockaddr(res, ss))
325 break; /* OK, identical */
329 /* We hit the end of the list without finding an
330 * address that was the same as ss. */
331 rprintf(FLOG, "no known address for \"%s\": "
332 "spoofed address?\n", name_buf);
333 strlcpy(name_buf, default_name, name_buf_size);
334 } else if (res == NULL) {
335 /* We hit the end of the list without finding an
336 * address that was the same as ss. */
337 rprintf(FLOG, "%s is not a known address for \"%s\": "
338 "spoofed address?\n", client_addr(fd), name_buf);
339 strlcpy(name_buf, default_name, name_buf_size);