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 struct sockaddr_storage ss;
47 socklen_t length = sizeof ss;
50 static char addr_buf[100];
51 static int initialised;
59 /* daemon over --rsh mode */
60 strcpy(addr_buf, "0.0.0.0");
61 if ((ssh_client = getenv("SSH_CLIENT")) != NULL) {
62 /* truncate SSH_CLIENT to just IP address */
63 p = strchr(ssh_client, ' ');
65 len = MIN((unsigned int) (p - ssh_client),
67 strncpy(addr_buf, ssh_client, len);
68 *(addr_buf + len) = '\0';
72 client_sockaddr(fd, &ss, &length);
73 getnameinfo((struct sockaddr *)&ss, length,
74 addr_buf, sizeof addr_buf, NULL, 0, NI_NUMERICHOST);
81 static int get_sockaddr_family(const struct sockaddr_storage *ss)
83 return ((struct sockaddr *) ss)->sa_family;
88 * Return the DNS name of the client.
90 * The name is statically cached so that repeated lookups are quick,
91 * so there is a limit of one lookup per customer.
93 * If anything goes wrong, including the name->addr->name check, then
94 * we just use "UNKNOWN", so you can use that value in hosts allow
97 * After translation from sockaddr to name we do a forward lookup to
98 * make sure nobody is spoofing PTR records.
100 char *client_name(int fd)
102 static char name_buf[100];
103 static char port_buf[100];
104 static int initialised;
105 struct sockaddr_storage ss, *ssp;
106 struct sockaddr_in sin;
108 struct sockaddr_in6 sin6;
115 strcpy(name_buf, default_name);
119 /* daemon over --rsh mode */
121 char *addr = client_addr(fd);
126 for (p = addr; *p && (dots <= 3); p++) {
131 /* more than 4 parts to IP address, must be ipv6 */
132 ssp = (struct sockaddr_storage *) &sin6;
133 ss_len = sizeof sin6;
134 memset(ssp, 0, ss_len);
135 inet_pton(AF_INET6, addr, &sin6.sin6_addr);
136 sin6.sin6_family = AF_INET6;
140 ssp = (struct sockaddr_storage *) &sin;
142 memset(ssp, 0, ss_len);
143 inet_pton(AF_INET, addr, &sin.sin_addr);
144 sin.sin_family = AF_INET;
151 client_sockaddr(fd, &ss, &ss_len);
155 if (!lookup_name(fd, ssp, ss_len, name_buf, sizeof name_buf,
156 port_buf, sizeof port_buf))
157 check_name(fd, ssp, name_buf);
165 * Get the sockaddr for the client.
167 * If it comes in as an ipv4 address mapped into IPv6 format then we
168 * convert it back to a regular IPv4.
170 void client_sockaddr(int fd,
171 struct sockaddr_storage *ss,
174 memset(ss, 0, sizeof *ss);
176 if (getpeername(fd, (struct sockaddr *) ss, ss_len)) {
177 /* FIXME: Can we really not continue? */
178 rprintf(FERROR, RSYNC_NAME ": getpeername on fd%d failed: %s\n",
179 fd, strerror(errno));
180 exit_cleanup(RERR_SOCKETIO);
184 if (get_sockaddr_family(ss) == AF_INET6 &&
185 IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)ss)->sin6_addr)) {
186 /* OK, so ss is in the IPv6 family, but it is really
187 * an IPv4 address: something like
188 * "::ffff:10.130.1.2". If we use it as-is, then the
189 * reverse lookup might fail or perhaps something else
190 * bad might happen. So instead we convert it to an
191 * equivalent address in the IPv4 address family. */
192 struct sockaddr_in6 sin6;
193 struct sockaddr_in *sin;
195 memcpy(&sin6, ss, sizeof sin6);
196 sin = (struct sockaddr_in *)ss;
197 memset(sin, 0, sizeof *sin);
198 sin->sin_family = AF_INET;
199 *ss_len = sizeof (struct sockaddr_in);
200 #if HAVE_SOCKADDR_IN_LEN
201 sin->sin_len = *ss_len;
203 sin->sin_port = sin6.sin6_port;
205 /* There is a macro to extract the mapped part
206 * (IN6_V4MAPPED_TO_SINADDR ?), but it does not seem
207 * to be present in the Linux headers. */
208 memcpy(&sin->sin_addr, &sin6.sin6_addr.s6_addr[12],
209 sizeof sin->sin_addr);
216 * Look up a name from @p ss into @p name_buf.
218 * @param fd file descriptor for client socket.
220 int lookup_name(int fd, const struct sockaddr_storage *ss,
222 char *name_buf, size_t name_buf_len,
223 char *port_buf, size_t port_buf_len)
228 name_err = getnameinfo((struct sockaddr *) ss, ss_len,
229 name_buf, name_buf_len,
230 port_buf, port_buf_len,
231 NI_NAMEREQD | NI_NUMERICSERV);
233 strcpy(name_buf, default_name);
234 rprintf(FERROR, RSYNC_NAME ": name lookup failed for %s: %s\n",
236 gai_strerror(name_err));
246 * Compare an addrinfo from the resolver to a sockinfo.
248 * Like strcmp, returns 0 for identical.
250 int compare_addrinfo_sockaddr(const struct addrinfo *ai,
251 const struct sockaddr_storage *ss)
253 int ss_family = get_sockaddr_family(ss);
254 const char fn[] = "compare_addrinfo_sockaddr";
256 if (ai->ai_family != ss_family) {
258 "%s: response family %d != %d\n",
259 fn, ai->ai_family, ss_family);
263 /* The comparison method depends on the particular AF. */
264 if (ss_family == AF_INET) {
265 const struct sockaddr_in *sin1, *sin2;
267 sin1 = (const struct sockaddr_in *) ss;
268 sin2 = (const struct sockaddr_in *) ai->ai_addr;
270 return memcmp(&sin1->sin_addr, &sin2->sin_addr,
271 sizeof sin1->sin_addr);
274 else if (ss_family == AF_INET6) {
275 const struct sockaddr_in6 *sin1, *sin2;
277 sin1 = (const struct sockaddr_in6 *) ss;
278 sin2 = (const struct sockaddr_in6 *) ai->ai_addr;
280 if (ai->ai_addrlen < sizeof (struct sockaddr_in6)) {
282 "%s: too short sockaddr_in6; length=%d\n",
287 if (memcmp(&sin1->sin6_addr, &sin2->sin6_addr,
288 sizeof sin1->sin6_addr))
291 #ifdef HAVE_SOCKADDR_IN6_SCOPE_ID
292 if (sin1->sin6_scope_id != sin2->sin6_scope_id)
306 * Do a forward lookup on @p name_buf and make sure it corresponds to
307 * @p ss -- otherwise we may be being spoofed. If we suspect we are,
308 * then we don't abort the connection but just emit a warning, and
309 * change @p name_buf to be "UNKNOWN".
311 * We don't do anything with the service when checking the name,
312 * because it doesn't seem that it could be spoofed in any way, and
313 * getaddrinfo on random service names seems to cause problems on AIX.
315 int check_name(int fd,
316 const struct sockaddr_storage *ss,
319 struct addrinfo hints, *res, *res0;
321 int ss_family = get_sockaddr_family(ss);
323 memset(&hints, 0, sizeof hints);
324 hints.ai_family = ss_family;
325 hints.ai_flags = AI_CANONNAME;
326 hints.ai_socktype = SOCK_STREAM;
327 error = getaddrinfo(name_buf, NULL, &hints, &res0);
330 RSYNC_NAME ": forward name lookup for %s failed: %s\n",
331 name_buf, gai_strerror(error));
332 strcpy(name_buf, default_name);
337 /* Given all these results, we expect that one of them will be
338 * the same as ss. The comparison is a bit complicated. */
339 for (res = res0; res; res = res->ai_next) {
340 if (!compare_addrinfo_sockaddr(res, ss))
341 break; /* OK, identical */
345 /* We hit the end of the list without finding an
346 * address that was the same as ss. */
347 rprintf(FERROR, RSYNC_NAME
348 ": no known address for \"%s\": "
349 "spoofed address?\n",
351 strcpy(name_buf, default_name);
352 } else if (res == NULL) {
353 /* We hit the end of the list without finding an
354 * address that was the same as ss. */
355 rprintf(FERROR, RSYNC_NAME
356 ": %s is not a known address for \"%s\": "
357 "spoofed address?\n",
360 strcpy(name_buf, default_name);