1 /* -*- c-file-style: "linux" -*-
3 rsync -- fast file replication program
5 Copyright (C) 1992-2001 by Andrew Tridgell <tridge@samba.org>
6 Copyright (C) 2001, 2002 by Martin Pool <mbp@samba.org>
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
19 along with this program; if not, write to the Free Software
20 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
26 * Functions for looking up the remote name or addr of a socket.
28 * This file is now converted to use the new-style getaddrinfo()
29 * interface, which supports IPv6 but is also supported on recent
30 * IPv4-only machines. On systems that don't have that interface, we
31 * emulate it using the KAME implementation.
36 static const char default_name[] = "UNKNOWN";
42 * Return the IP addr of the client as a string
44 char *client_addr(int fd)
46 static char addr_buf[100];
47 static int initialised;
48 struct sockaddr_storage ss;
49 socklen_t length = sizeof ss;
57 if (am_server) { /* daemon over --rsh mode */
58 strcpy(addr_buf, "0.0.0.0");
59 if ((ssh_info = getenv("SSH_CONNECTION")) != NULL
60 || (ssh_info = getenv("SSH_CLIENT")) != NULL
61 || (ssh_info = getenv("SSH2_CLIENT")) != NULL) {
62 strlcpy(addr_buf, ssh_info, sizeof addr_buf);
63 /* Truncate the value to just the IP address. */
64 if ((p = strchr(addr_buf, ' ')) != NULL)
68 client_sockaddr(fd, &ss, &length);
69 getnameinfo((struct sockaddr *)&ss, length,
70 addr_buf, sizeof addr_buf, NULL, 0, NI_NUMERICHOST);
77 static int get_sockaddr_family(const struct sockaddr_storage *ss)
79 return ((struct sockaddr *) ss)->sa_family;
84 * Return the DNS name of the client.
86 * The name is statically cached so that repeated lookups are quick,
87 * so there is a limit of one lookup per customer.
89 * If anything goes wrong, including the name->addr->name check, then
90 * we just use "UNKNOWN", so you can use that value in hosts allow
93 * After translation from sockaddr to name we do a forward lookup to
94 * make sure nobody is spoofing PTR records.
96 char *client_name(int fd)
98 static char name_buf[100];
99 static char port_buf[100];
100 static int initialised;
101 struct sockaddr_storage ss;
107 strcpy(name_buf, default_name);
110 memset(&ss, 0, sizeof ss);
112 if (am_server) { /* daemon over --rsh mode */
113 char *addr = client_addr(fd);
114 struct addrinfo hint, *answer;
117 memset(&hint, 0, sizeof hint);
119 #ifdef AI_NUMERICHOST
120 hint.ai_flags = AI_NUMERICHOST;
122 hint.ai_socktype = SOCK_STREAM;
124 if ((err = getaddrinfo(addr, NULL, &hint, &answer)) != 0) {
125 rprintf(FLOG, "malformed address %s: %s\n",
126 addr, gai_strerror(err));
130 switch (answer->ai_family) {
132 ss_len = sizeof (struct sockaddr_in);
133 memcpy(&ss, answer->ai_addr, ss_len);
137 ss_len = sizeof (struct sockaddr_in6);
138 memcpy(&ss, answer->ai_addr, ss_len);
142 freeaddrinfo(answer);
145 client_sockaddr(fd, &ss, &ss_len);
148 if (lookup_name(fd, &ss, ss_len, name_buf, sizeof name_buf,
149 port_buf, sizeof port_buf) == 0)
150 check_name(fd, &ss, name_buf);
158 * Get the sockaddr for the client.
160 * If it comes in as an ipv4 address mapped into IPv6 format then we
161 * convert it back to a regular IPv4.
163 void client_sockaddr(int fd,
164 struct sockaddr_storage *ss,
167 memset(ss, 0, sizeof *ss);
169 if (getpeername(fd, (struct sockaddr *) ss, ss_len)) {
170 /* FIXME: Can we really not continue? */
171 rsyserr(FLOG, errno, "getpeername on fd%d failed", fd);
172 exit_cleanup(RERR_SOCKETIO);
176 if (get_sockaddr_family(ss) == AF_INET6 &&
177 IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)ss)->sin6_addr)) {
178 /* OK, so ss is in the IPv6 family, but it is really
179 * an IPv4 address: something like
180 * "::ffff:10.130.1.2". If we use it as-is, then the
181 * reverse lookup might fail or perhaps something else
182 * bad might happen. So instead we convert it to an
183 * equivalent address in the IPv4 address family. */
184 struct sockaddr_in6 sin6;
185 struct sockaddr_in *sin;
187 memcpy(&sin6, ss, sizeof sin6);
188 sin = (struct sockaddr_in *)ss;
189 memset(sin, 0, sizeof *sin);
190 sin->sin_family = AF_INET;
191 *ss_len = sizeof (struct sockaddr_in);
192 #ifdef HAVE_SOCKADDR_IN_LEN
193 sin->sin_len = *ss_len;
195 sin->sin_port = sin6.sin6_port;
197 /* There is a macro to extract the mapped part
198 * (IN6_V4MAPPED_TO_SINADDR ?), but it does not seem
199 * to be present in the Linux headers. */
200 memcpy(&sin->sin_addr, &sin6.sin6_addr.s6_addr[12],
201 sizeof sin->sin_addr);
208 * Look up a name from @p ss into @p name_buf.
210 * @param fd file descriptor for client socket.
212 int lookup_name(int fd, const struct sockaddr_storage *ss,
214 char *name_buf, size_t name_buf_len,
215 char *port_buf, size_t port_buf_len)
220 name_err = getnameinfo((struct sockaddr *) ss, ss_len,
221 name_buf, name_buf_len,
222 port_buf, port_buf_len,
223 NI_NAMEREQD | NI_NUMERICSERV);
225 strcpy(name_buf, default_name);
226 rprintf(FLOG, "name lookup failed for %s: %s\n",
227 client_addr(fd), gai_strerror(name_err));
237 * Compare an addrinfo from the resolver to a sockinfo.
239 * Like strcmp, returns 0 for identical.
241 int compare_addrinfo_sockaddr(const struct addrinfo *ai,
242 const struct sockaddr_storage *ss)
244 int ss_family = get_sockaddr_family(ss);
245 const char fn[] = "compare_addrinfo_sockaddr";
247 if (ai->ai_family != ss_family) {
248 rprintf(FLOG, "%s: response family %d != %d\n",
249 fn, ai->ai_family, ss_family);
253 /* The comparison method depends on the particular AF. */
254 if (ss_family == AF_INET) {
255 const struct sockaddr_in *sin1, *sin2;
257 sin1 = (const struct sockaddr_in *) ss;
258 sin2 = (const struct sockaddr_in *) ai->ai_addr;
260 return memcmp(&sin1->sin_addr, &sin2->sin_addr,
261 sizeof sin1->sin_addr);
265 if (ss_family == AF_INET6) {
266 const struct sockaddr_in6 *sin1, *sin2;
268 sin1 = (const struct sockaddr_in6 *) ss;
269 sin2 = (const struct sockaddr_in6 *) ai->ai_addr;
271 if (ai->ai_addrlen < sizeof (struct sockaddr_in6)) {
272 rprintf(FLOG, "%s: too short sockaddr_in6; length=%d\n",
277 if (memcmp(&sin1->sin6_addr, &sin2->sin6_addr,
278 sizeof sin1->sin6_addr))
281 #ifdef HAVE_SOCKADDR_IN6_SCOPE_ID
282 if (sin1->sin6_scope_id != sin2->sin6_scope_id)
295 * Do a forward lookup on @p name_buf and make sure it corresponds to
296 * @p ss -- otherwise we may be being spoofed. If we suspect we are,
297 * then we don't abort the connection but just emit a warning, and
298 * change @p name_buf to be "UNKNOWN".
300 * We don't do anything with the service when checking the name,
301 * because it doesn't seem that it could be spoofed in any way, and
302 * getaddrinfo on random service names seems to cause problems on AIX.
304 int check_name(int fd,
305 const struct sockaddr_storage *ss,
308 struct addrinfo hints, *res, *res0;
310 int ss_family = get_sockaddr_family(ss);
312 memset(&hints, 0, sizeof hints);
313 hints.ai_family = ss_family;
314 hints.ai_flags = AI_CANONNAME;
315 hints.ai_socktype = SOCK_STREAM;
316 error = getaddrinfo(name_buf, NULL, &hints, &res0);
318 rprintf(FLOG, "forward name lookup for %s failed: %s\n",
319 name_buf, gai_strerror(error));
320 strcpy(name_buf, default_name);
324 /* Given all these results, we expect that one of them will be
325 * the same as ss. The comparison is a bit complicated. */
326 for (res = res0; res; res = res->ai_next) {
327 if (!compare_addrinfo_sockaddr(res, ss))
328 break; /* OK, identical */
332 /* We hit the end of the list without finding an
333 * address that was the same as ss. */
334 rprintf(FLOG, "no known address for \"%s\": "
335 "spoofed address?\n", name_buf);
336 strcpy(name_buf, default_name);
337 } else if (res == NULL) {
338 /* We hit the end of the list without finding an
339 * address that was the same as ss. */
340 rprintf(FLOG, "%s is not a known address for \"%s\": "
341 "spoofed address?\n", client_addr(fd), name_buf);
342 strcpy(name_buf, default_name);