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) 2002-2007 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 version 3 as
10 * published by the Free Software Foundation.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License along
18 * with this program; if not, visit the http://fsf.org website.
22 * This file is now converted to use the new-style getaddrinfo()
23 * interface, which supports IPv6 but is also supported on recent
24 * IPv4-only machines. On systems that don't have that interface, we
25 * emulate it using the KAME implementation.
30 static const char default_name[] = "UNKNOWN";
35 * Return the IP addr of the client as a string
37 char *client_addr(int fd)
39 static char addr_buf[100];
40 static int initialised;
41 struct sockaddr_storage ss;
42 socklen_t length = sizeof ss;
50 if (am_server) { /* daemon over --rsh mode */
51 strlcpy(addr_buf, "0.0.0.0", sizeof addr_buf);
52 if ((ssh_info = getenv("SSH_CONNECTION")) != NULL
53 || (ssh_info = getenv("SSH_CLIENT")) != NULL
54 || (ssh_info = getenv("SSH2_CLIENT")) != NULL) {
55 strlcpy(addr_buf, ssh_info, sizeof addr_buf);
56 /* Truncate the value to just the IP address. */
57 if ((p = strchr(addr_buf, ' ')) != NULL)
61 client_sockaddr(fd, &ss, &length);
62 getnameinfo((struct sockaddr *)&ss, length,
63 addr_buf, sizeof addr_buf, NULL, 0, NI_NUMERICHOST);
70 static int get_sockaddr_family(const struct sockaddr_storage *ss)
72 return ((struct sockaddr *) ss)->sa_family;
77 * Return the DNS name of the client.
79 * The name is statically cached so that repeated lookups are quick,
80 * so there is a limit of one lookup per customer.
82 * If anything goes wrong, including the name->addr->name check, then
83 * we just use "UNKNOWN", so you can use that value in hosts allow
86 * After translation from sockaddr to name we do a forward lookup to
87 * make sure nobody is spoofing PTR records.
89 char *client_name(int fd)
91 static char name_buf[100];
92 static char port_buf[100];
93 static int initialised;
94 struct sockaddr_storage ss;
100 strlcpy(name_buf, default_name, sizeof name_buf);
103 memset(&ss, 0, sizeof ss);
105 if (am_server) { /* daemon over --rsh mode */
106 char *addr = client_addr(fd);
107 struct addrinfo hint, *answer;
110 memset(&hint, 0, sizeof hint);
112 #ifdef AI_NUMERICHOST
113 hint.ai_flags = AI_NUMERICHOST;
115 hint.ai_socktype = SOCK_STREAM;
117 if ((err = getaddrinfo(addr, NULL, &hint, &answer)) != 0) {
118 rprintf(FLOG, "malformed address %s: %s\n",
119 addr, gai_strerror(err));
123 switch (answer->ai_family) {
125 ss_len = sizeof (struct sockaddr_in);
126 memcpy(&ss, answer->ai_addr, ss_len);
130 ss_len = sizeof (struct sockaddr_in6);
131 memcpy(&ss, answer->ai_addr, ss_len);
135 exit_cleanup(RERR_SOCKETIO);
137 freeaddrinfo(answer);
140 client_sockaddr(fd, &ss, &ss_len);
143 if (lookup_name(fd, &ss, ss_len, name_buf, sizeof name_buf,
144 port_buf, sizeof port_buf) == 0)
145 check_name(fd, &ss, name_buf, sizeof name_buf);
153 * Get the sockaddr for the client.
155 * If it comes in as an ipv4 address mapped into IPv6 format then we
156 * convert it back to a regular IPv4.
158 void client_sockaddr(int fd,
159 struct sockaddr_storage *ss,
162 memset(ss, 0, sizeof *ss);
164 if (getpeername(fd, (struct sockaddr *) ss, ss_len)) {
165 /* FIXME: Can we really not continue? */
166 rsyserr(FLOG, errno, "getpeername on fd%d failed", fd);
167 exit_cleanup(RERR_SOCKETIO);
171 if (get_sockaddr_family(ss) == AF_INET6 &&
172 IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)ss)->sin6_addr)) {
173 /* OK, so ss is in the IPv6 family, but it is really
174 * an IPv4 address: something like
175 * "::ffff:10.130.1.2". If we use it as-is, then the
176 * reverse lookup might fail or perhaps something else
177 * bad might happen. So instead we convert it to an
178 * equivalent address in the IPv4 address family. */
179 struct sockaddr_in6 sin6;
180 struct sockaddr_in *sin;
182 memcpy(&sin6, ss, sizeof sin6);
183 sin = (struct sockaddr_in *)ss;
184 memset(sin, 0, sizeof *sin);
185 sin->sin_family = AF_INET;
186 *ss_len = sizeof (struct sockaddr_in);
187 #ifdef HAVE_SOCKADDR_IN_LEN
188 sin->sin_len = *ss_len;
190 sin->sin_port = sin6.sin6_port;
192 /* There is a macro to extract the mapped part
193 * (IN6_V4MAPPED_TO_SINADDR ?), but it does not seem
194 * to be present in the Linux headers. */
195 memcpy(&sin->sin_addr, &sin6.sin6_addr.s6_addr[12],
196 sizeof sin->sin_addr);
203 * Look up a name from @p ss into @p name_buf.
205 * @param fd file descriptor for client socket.
207 int lookup_name(int fd, const struct sockaddr_storage *ss,
209 char *name_buf, size_t name_buf_size,
210 char *port_buf, size_t port_buf_size)
215 name_err = getnameinfo((struct sockaddr *) ss, ss_len,
216 name_buf, name_buf_size,
217 port_buf, port_buf_size,
218 NI_NAMEREQD | NI_NUMERICSERV);
220 strlcpy(name_buf, default_name, name_buf_size);
221 rprintf(FLOG, "name lookup failed for %s: %s\n",
222 client_addr(fd), gai_strerror(name_err));
232 * Compare an addrinfo from the resolver to a sockinfo.
234 * Like strcmp, returns 0 for identical.
236 int compare_addrinfo_sockaddr(const struct addrinfo *ai,
237 const struct sockaddr_storage *ss)
239 int ss_family = get_sockaddr_family(ss);
240 const char fn[] = "compare_addrinfo_sockaddr";
242 if (ai->ai_family != ss_family) {
243 rprintf(FLOG, "%s: response family %d != %d\n",
244 fn, ai->ai_family, ss_family);
248 /* The comparison method depends on the particular AF. */
249 if (ss_family == AF_INET) {
250 const struct sockaddr_in *sin1, *sin2;
252 sin1 = (const struct sockaddr_in *) ss;
253 sin2 = (const struct sockaddr_in *) ai->ai_addr;
255 return memcmp(&sin1->sin_addr, &sin2->sin_addr,
256 sizeof sin1->sin_addr);
260 if (ss_family == AF_INET6) {
261 const struct sockaddr_in6 *sin1, *sin2;
263 sin1 = (const struct sockaddr_in6 *) ss;
264 sin2 = (const struct sockaddr_in6 *) ai->ai_addr;
266 if (ai->ai_addrlen < sizeof (struct sockaddr_in6)) {
267 rprintf(FLOG, "%s: too short sockaddr_in6; length=%d\n",
272 if (memcmp(&sin1->sin6_addr, &sin2->sin6_addr,
273 sizeof sin1->sin6_addr))
276 #ifdef HAVE_SOCKADDR_IN6_SCOPE_ID
277 if (sin1->sin6_scope_id != sin2->sin6_scope_id)
290 * Do a forward lookup on @p name_buf and make sure it corresponds to
291 * @p ss -- otherwise we may be being spoofed. If we suspect we are,
292 * then we don't abort the connection but just emit a warning, and
293 * change @p name_buf to be "UNKNOWN".
295 * We don't do anything with the service when checking the name,
296 * because it doesn't seem that it could be spoofed in any way, and
297 * getaddrinfo on random service names seems to cause problems on AIX.
299 int check_name(int fd,
300 const struct sockaddr_storage *ss,
301 char *name_buf, size_t name_buf_size)
303 struct addrinfo hints, *res, *res0;
305 int ss_family = get_sockaddr_family(ss);
307 memset(&hints, 0, sizeof hints);
308 hints.ai_family = ss_family;
309 hints.ai_flags = AI_CANONNAME;
310 hints.ai_socktype = SOCK_STREAM;
311 error = getaddrinfo(name_buf, NULL, &hints, &res0);
313 rprintf(FLOG, "forward name lookup for %s failed: %s\n",
314 name_buf, gai_strerror(error));
315 strlcpy(name_buf, default_name, name_buf_size);
319 /* Given all these results, we expect that one of them will be
320 * the same as ss. The comparison is a bit complicated. */
321 for (res = res0; res; res = res->ai_next) {
322 if (!compare_addrinfo_sockaddr(res, ss))
323 break; /* OK, identical */
327 /* We hit the end of the list without finding an
328 * address that was the same as ss. */
329 rprintf(FLOG, "no known address for \"%s\": "
330 "spoofed address?\n", name_buf);
331 strlcpy(name_buf, default_name, name_buf_size);
332 } else if (res == NULL) {
333 /* We hit the end of the list without finding an
334 * address that was the same as ss. */
335 rprintf(FLOG, "%s is not a known address for \"%s\": "
336 "spoofed address?\n", client_addr(fd), name_buf);
337 strlcpy(name_buf, default_name, name_buf_size);