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;
46 static char addr_buf[100];
47 static int initialised;
49 if (initialised) return addr_buf;
53 client_sockaddr(fd, &ss, &length);
55 getnameinfo((struct sockaddr *)&ss, length,
56 addr_buf, sizeof(addr_buf), NULL, 0, NI_NUMERICHOST);
62 static int get_sockaddr_family(const struct sockaddr_storage *ss)
64 return ((struct sockaddr *) ss)->sa_family;
69 * Return the DNS name of the client.
71 * The name is statically cached so that repeated lookups are quick,
72 * so there is a limit of one lookup per customer.
74 * If anything goes wrong, including the name->addr->name check, then
75 * we just use "UNKNOWN", so you can use that value in hosts allow
78 * After translation from sockaddr to name we do a forward lookup to
79 * make sure nobody is spoofing PTR records.
81 char *client_name(int fd)
83 struct sockaddr_storage ss;
84 socklen_t ss_len = sizeof ss;
85 static char name_buf[100];
86 static char port_buf[100];
87 static int initialised;
89 if (initialised) return name_buf;
91 strcpy(name_buf, default_name);
94 client_sockaddr(fd, &ss, &ss_len);
96 if (!lookup_name(fd, &ss, ss_len, name_buf, sizeof name_buf,
97 port_buf, sizeof port_buf))
98 check_name(fd, &ss, name_buf);
106 * Get the sockaddr for the client.
108 * If it comes in as an ipv4 address mapped into IPv6 format then we
109 * convert it back to a regular IPv4.
111 void client_sockaddr(int fd,
112 struct sockaddr_storage *ss,
115 if (getpeername(fd, (struct sockaddr *) ss, ss_len)) {
116 /* FIXME: Can we really not continue? */
117 rprintf(FERROR, RSYNC_NAME ": getpeername on fd%d failed: %s\n",
118 fd, strerror(errno));
119 exit_cleanup(RERR_SOCKETIO);
123 if (get_sockaddr_family(ss) == AF_INET6 &&
124 IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)ss)->sin6_addr)) {
125 /* OK, so ss is in the IPv6 family, but it is really
126 * an IPv4 address: something like
127 * "::ffff:10.130.1.2". If we use it as-is, then the
128 * reverse lookup might fail or perhaps something else
129 * bad might happen. So instead we convert it to an
130 * equivalent address in the IPv4 address family. */
131 struct sockaddr_in6 sin6;
132 struct sockaddr_in *sin;
134 memcpy(&sin6, ss, sizeof(sin6));
135 sin = (struct sockaddr_in *)ss;
136 memset(sin, 0, sizeof(*sin));
137 sin->sin_family = AF_INET;
138 *ss_len = sizeof(struct sockaddr_in);
139 #ifdef HAVE_SOCKADDR_LEN
140 sin->sin_len = *ss_len;
142 sin->sin_port = sin6.sin6_port;
144 /* There is a macro to extract the mapped part
145 * (IN6_V4MAPPED_TO_SINADDR ?), but it does not seem
146 * to be present in the Linux headers. */
147 memcpy(&sin->sin_addr, &sin6.sin6_addr.s6_addr[12],
148 sizeof(sin->sin_addr));
155 * Look up a name from @p ss into @p name_buf.
157 * @param fd file descriptor for client socket.
159 int lookup_name(int fd, const struct sockaddr_storage *ss,
161 char *name_buf, size_t name_buf_len,
162 char *port_buf, size_t port_buf_len)
167 name_err = getnameinfo((struct sockaddr *) ss, ss_len,
168 name_buf, name_buf_len,
169 port_buf, port_buf_len,
170 NI_NAMEREQD | NI_NUMERICSERV);
172 strcpy(name_buf, default_name);
173 rprintf(FERROR, RSYNC_NAME ": name lookup failed for %s: %s\n",
175 gai_strerror(name_err));
185 * Compare an addrinfo from the resolver to a sockinfo.
187 * Like strcmp, returns 0 for identical.
189 int compare_addrinfo_sockaddr(const struct addrinfo *ai,
190 const struct sockaddr_storage *ss)
192 int ss_family = get_sockaddr_family(ss);
193 const char fn[] = "compare_addrinfo_sockaddr";
195 if (ai->ai_family != ss_family) {
197 "%s: response family %d != %d\n",
198 fn, ai->ai_family, ss_family);
202 /* The comparison method depends on the particular AF. */
203 if (ss_family == AF_INET) {
204 const struct sockaddr_in *sin1, *sin2;
206 sin1 = (const struct sockaddr_in *) ss;
207 sin2 = (const struct sockaddr_in *) ai->ai_addr;
209 return memcmp(&sin1->sin_addr, &sin2->sin_addr,
210 sizeof sin1->sin_addr);
213 else if (ss_family == AF_INET6) {
214 const struct sockaddr_in6 *sin1, *sin2;
216 sin1 = (const struct sockaddr_in6 *) ss;
217 sin2 = (const struct sockaddr_in6 *) ai->ai_addr;
219 return memcmp(&sin1->sin6_addr, &sin2->sin6_addr,
220 sizeof sin1->sin6_addr);
231 * Do a forward lookup on @p name_buf and make sure it corresponds to
232 * @p ss -- otherwise we may be being spoofed. If we suspect we are,
233 * then we don't abort the connection but just emit a warning, and
234 * change @p name_buf to be "UNKNOWN".
236 * We don't do anything with the service when checking the name,
237 * because it doesn't seem that it could be spoofed in any way, and
238 * getaddrinfo on random service names seems to cause problems on AIX.
240 int check_name(int fd,
241 const struct sockaddr_storage *ss,
244 struct addrinfo hints, *res, *res0;
246 int ss_family = get_sockaddr_family(ss);
248 memset(&hints, 0, sizeof(hints));
249 hints.ai_family = ss_family;
250 hints.ai_flags = AI_CANONNAME;
251 hints.ai_socktype = SOCK_STREAM;
252 error = getaddrinfo(name_buf, NULL, &hints, &res0);
255 RSYNC_NAME ": forward name lookup for %s failed: %s\n",
256 name_buf, gai_strerror(error));
257 strcpy(name_buf, default_name);
262 /* Given all these results, we expect that one of them will be
263 * the same as ss. The comparison is a bit complicated. */
264 for (res = res0; res; res = res->ai_next) {
265 if (!compare_addrinfo_sockaddr(res, ss))
266 break; /* OK, identical */
270 /* We hit the end of the list without finding an
271 * address that was the same as ss. */
272 rprintf(FERROR, RSYNC_NAME
273 ": no known address for \"%s\": "
274 "spoofed address?\n",
276 strcpy(name_buf, default_name);
277 } else if (res == NULL) {
278 /* We hit the end of the list without finding an
279 * address that was the same as ss. */
280 rprintf(FERROR, RSYNC_NAME
281 ": %s is not a known address for \"%s\": "
282 "spoofed address?\n",
285 strcpy(name_buf, default_name);