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";
40 * Return the IP addr of the client as a string
42 char *client_addr(int fd)
44 struct sockaddr_storage ss;
45 socklen_t length = sizeof ss;
47 static char addr_buf[100];
48 static int initialised;
50 if (initialised) return addr_buf;
54 ssh_client = getenv("SSH_CLIENT");
55 if (ssh_client != NULL) {
56 strlcpy(addr_buf, ssh_client, sizeof(addr_buf));
57 /* truncate SSH_CLIENT to just IP address */
58 p = strchr(addr_buf, ' ');
62 strlcpy(addr_buf, "0.0.0.0", sizeof("0.0.0.0"));
64 client_sockaddr(fd, &ss, &length);
66 getnameinfo((struct sockaddr *)&ss, length,
67 addr_buf, sizeof(addr_buf), NULL, 0, NI_NUMERICHOST);
73 static int get_sockaddr_family(const struct sockaddr_storage *ss)
75 return ((struct sockaddr *) ss)->sa_family;
80 * Return the DNS name of the client.
82 * The name is statically cached so that repeated lookups are quick,
83 * so there is a limit of one lookup per customer.
85 * If anything goes wrong, including the name->addr->name check, then
86 * we just use "UNKNOWN", so you can use that value in hosts allow
89 * After translation from sockaddr to name we do a forward lookup to
90 * make sure nobody is spoofing PTR records.
92 char *client_name(int fd)
94 static char name_buf[100];
95 static char port_buf[100];
96 static int initialised;
98 if (initialised) return name_buf;
100 strcpy(name_buf, default_name);
103 if (getenv("SSH_CLIENT") != NULL) {
104 /* Look up name of IP address given in $SSH_CLIENT */
107 struct sockaddr_in6 sin;
110 struct sockaddr_in sin;
112 socklen_t sin_len = sizeof sin;
114 memset(&sin, 0, sin_len);
116 inet_pton(af, client_addr(fd), &sin.sin_addr.s_addr);
118 if (!lookup_name(fd, (struct sockaddr_storage *)&sin, sin_len,
119 name_buf, sizeof name_buf, port_buf, sizeof port_buf))
120 check_name(fd, (struct sockaddr_storage *)&sin, name_buf);
122 struct sockaddr_storage ss;
123 socklen_t ss_len = sizeof ss;
125 client_sockaddr(fd, &ss, &ss_len);
127 if (!lookup_name(fd, &ss, ss_len, name_buf, sizeof name_buf,
128 port_buf, sizeof port_buf))
129 check_name(fd, &ss, name_buf);
138 * Get the sockaddr for the client.
140 * If it comes in as an ipv4 address mapped into IPv6 format then we
141 * convert it back to a regular IPv4.
143 void client_sockaddr(int fd,
144 struct sockaddr_storage *ss,
147 if (getpeername(fd, (struct sockaddr *) ss, ss_len)) {
148 /* FIXME: Can we really not continue? */
149 rprintf(FERROR, RSYNC_NAME ": getpeername on fd%d failed: %s\n",
150 fd, strerror(errno));
151 exit_cleanup(RERR_SOCKETIO);
155 if (get_sockaddr_family(ss) == AF_INET6 &&
156 IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)ss)->sin6_addr)) {
157 /* OK, so ss is in the IPv6 family, but it is really
158 * an IPv4 address: something like
159 * "::ffff:10.130.1.2". If we use it as-is, then the
160 * reverse lookup might fail or perhaps something else
161 * bad might happen. So instead we convert it to an
162 * equivalent address in the IPv4 address family. */
163 struct sockaddr_in6 sin6;
164 struct sockaddr_in *sin;
166 memcpy(&sin6, ss, sizeof(sin6));
167 sin = (struct sockaddr_in *)ss;
168 memset(sin, 0, sizeof(*sin));
169 sin->sin_family = AF_INET;
170 *ss_len = sizeof(struct sockaddr_in);
171 #ifdef HAVE_SOCKADDR_LEN
172 sin->sin_len = *ss_len;
174 sin->sin_port = sin6.sin6_port;
176 /* There is a macro to extract the mapped part
177 * (IN6_V4MAPPED_TO_SINADDR ?), but it does not seem
178 * to be present in the Linux headers. */
179 memcpy(&sin->sin_addr, &sin6.sin6_addr.s6_addr[12],
180 sizeof(sin->sin_addr));
187 * Look up a name from @p ss into @p name_buf.
189 * @param fd file descriptor for client socket.
191 int lookup_name(int fd, const struct sockaddr_storage *ss,
193 char *name_buf, size_t name_buf_len,
194 char *port_buf, size_t port_buf_len)
199 name_err = getnameinfo((struct sockaddr *) ss, ss_len,
200 name_buf, name_buf_len,
201 port_buf, port_buf_len,
202 NI_NAMEREQD | NI_NUMERICSERV);
204 strcpy(name_buf, default_name);
205 rprintf(FERROR, RSYNC_NAME ": name lookup failed for %s: %s\n",
207 gai_strerror(name_err));
217 * Compare an addrinfo from the resolver to a sockinfo.
219 * Like strcmp, returns 0 for identical.
221 int compare_addrinfo_sockaddr(const struct addrinfo *ai,
222 const struct sockaddr_storage *ss)
224 int ss_family = get_sockaddr_family(ss);
225 const char fn[] = "compare_addrinfo_sockaddr";
227 if (ai->ai_family != ss_family) {
229 "%s: response family %d != %d\n",
230 fn, ai->ai_family, ss_family);
234 /* The comparison method depends on the particular AF. */
235 if (ss_family == AF_INET) {
236 const struct sockaddr_in *sin1, *sin2;
238 sin1 = (const struct sockaddr_in *) ss;
239 sin2 = (const struct sockaddr_in *) ai->ai_addr;
241 return memcmp(&sin1->sin_addr, &sin2->sin_addr,
242 sizeof sin1->sin_addr);
245 else if (ss_family == AF_INET6) {
246 const struct sockaddr_in6 *sin1, *sin2;
248 sin1 = (const struct sockaddr_in6 *) ss;
249 sin2 = (const struct sockaddr_in6 *) ai->ai_addr;
251 return memcmp(&sin1->sin6_addr, &sin2->sin6_addr,
252 sizeof sin1->sin6_addr);
263 * Do a forward lookup on @p name_buf and make sure it corresponds to
264 * @p ss -- otherwise we may be being spoofed. If we suspect we are,
265 * then we don't abort the connection but just emit a warning, and
266 * change @p name_buf to be "UNKNOWN".
268 * We don't do anything with the service when checking the name,
269 * because it doesn't seem that it could be spoofed in any way, and
270 * getaddrinfo on random service names seems to cause problems on AIX.
272 int check_name(int fd,
273 const struct sockaddr_storage *ss,
276 struct addrinfo hints, *res, *res0;
278 int ss_family = get_sockaddr_family(ss);
280 memset(&hints, 0, sizeof(hints));
281 hints.ai_family = ss_family;
282 hints.ai_flags = AI_CANONNAME;
283 hints.ai_socktype = SOCK_STREAM;
284 error = getaddrinfo(name_buf, NULL, &hints, &res0);
287 RSYNC_NAME ": forward name lookup for %s failed: %s\n",
288 name_buf, gai_strerror(error));
289 strcpy(name_buf, default_name);
294 /* Given all these results, we expect that one of them will be
295 * the same as ss. The comparison is a bit complicated. */
296 for (res = res0; res; res = res->ai_next) {
297 if (!compare_addrinfo_sockaddr(res, ss))
298 break; /* OK, identical */
302 /* We hit the end of the list without finding an
303 * address that was the same as ss. */
304 rprintf(FERROR, RSYNC_NAME
305 ": no known address for \"%s\": "
306 "spoofed address?\n",
308 strcpy(name_buf, default_name);
309 } else if (res == NULL) {
310 /* We hit the end of the list without finding an
311 * address that was the same as ss. */
312 rprintf(FERROR, RSYNC_NAME
313 ": %s is not a known address for \"%s\": "
314 "spoofed address?\n",
317 strcpy(name_buf, default_name);