]>
git.ipfire.org Git - thirdparty/rsync.git/blob - clientname.c
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 if ((ssh_client
= getenv("SSH_CLIENT")) != NULL
) {
55 strlcpy(addr_buf
, ssh_client
, sizeof(addr_buf
));
56 /* truncate SSH_CLIENT to just IP address */
57 p
= strchr(addr_buf
, ' ');
61 strlcpy(addr_buf
, "0.0.0.0", sizeof("0.0.0.0"));
63 client_sockaddr(fd
, &ss
, &length
);
65 getnameinfo((struct sockaddr
*)&ss
, length
,
66 addr_buf
, sizeof(addr_buf
), NULL
, 0, NI_NUMERICHOST
);
72 static int get_sockaddr_family(const struct sockaddr_storage
*ss
)
74 return ((struct sockaddr
*) ss
)->sa_family
;
79 * Return the DNS name of the client.
81 * The name is statically cached so that repeated lookups are quick,
82 * so there is a limit of one lookup per customer.
84 * If anything goes wrong, including the name->addr->name check, then
85 * we just use "UNKNOWN", so you can use that value in hosts allow
88 * After translation from sockaddr to name we do a forward lookup to
89 * make sure nobody is spoofing PTR records.
91 char *client_name(int fd
)
93 static char name_buf
[100];
94 static char port_buf
[100];
95 static int initialised
;
97 if (initialised
) return name_buf
;
99 strcpy(name_buf
, default_name
);
102 if (getenv("SSH_CLIENT") != NULL
) {
103 /* Look up name of IP address given in $SSH_CLIENT */
106 struct sockaddr_in6 sin
;
109 struct sockaddr_in sin
;
111 socklen_t sin_len
= sizeof sin
;
113 memset(&sin
, 0, sin_len
);
116 sin
.sin6_family
= af
;
117 inet_pton(af
, client_addr(fd
), &sin
.sin6_addr
.s6_addr
);
120 inet_pton(af
, client_addr(fd
), &sin
.sin_addr
.s_addr
);
123 if (!lookup_name(fd
, (struct sockaddr_storage
*)&sin
, sin_len
,
124 name_buf
, sizeof name_buf
, port_buf
, sizeof port_buf
))
125 check_name(fd
, (struct sockaddr_storage
*)&sin
, name_buf
);
127 struct sockaddr_storage ss
;
128 socklen_t ss_len
= sizeof ss
;
130 client_sockaddr(fd
, &ss
, &ss_len
);
132 if (!lookup_name(fd
, &ss
, ss_len
, name_buf
, sizeof name_buf
,
133 port_buf
, sizeof port_buf
))
134 check_name(fd
, &ss
, name_buf
);
143 * Get the sockaddr for the client.
145 * If it comes in as an ipv4 address mapped into IPv6 format then we
146 * convert it back to a regular IPv4.
148 void client_sockaddr(int fd
,
149 struct sockaddr_storage
*ss
,
152 if (getpeername(fd
, (struct sockaddr
*) ss
, ss_len
)) {
153 /* FIXME: Can we really not continue? */
154 rprintf(FERROR
, RSYNC_NAME
": getpeername on fd%d failed: %s\n",
155 fd
, strerror(errno
));
156 exit_cleanup(RERR_SOCKETIO
);
160 if (get_sockaddr_family(ss
) == AF_INET6
&&
161 IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6
*)ss
)->sin6_addr
)) {
162 /* OK, so ss is in the IPv6 family, but it is really
163 * an IPv4 address: something like
164 * "::ffff:10.130.1.2". If we use it as-is, then the
165 * reverse lookup might fail or perhaps something else
166 * bad might happen. So instead we convert it to an
167 * equivalent address in the IPv4 address family. */
168 struct sockaddr_in6 sin6
;
169 struct sockaddr_in
*sin
;
171 memcpy(&sin6
, ss
, sizeof(sin6
));
172 sin
= (struct sockaddr_in
*)ss
;
173 memset(sin
, 0, sizeof(*sin
));
174 sin
->sin_family
= AF_INET
;
175 *ss_len
= sizeof(struct sockaddr_in
);
176 #ifdef HAVE_SOCKADDR_LEN
177 sin
->sin_len
= *ss_len
;
179 sin
->sin_port
= sin6
.sin6_port
;
181 /* There is a macro to extract the mapped part
182 * (IN6_V4MAPPED_TO_SINADDR ?), but it does not seem
183 * to be present in the Linux headers. */
184 memcpy(&sin
->sin_addr
, &sin6
.sin6_addr
.s6_addr
[12],
185 sizeof(sin
->sin_addr
));
192 * Look up a name from @p ss into @p name_buf.
194 * @param fd file descriptor for client socket.
196 int lookup_name(int fd
, const struct sockaddr_storage
*ss
,
198 char *name_buf
, size_t name_buf_len
,
199 char *port_buf
, size_t port_buf_len
)
204 name_err
= getnameinfo((struct sockaddr
*) ss
, ss_len
,
205 name_buf
, name_buf_len
,
206 port_buf
, port_buf_len
,
207 NI_NAMEREQD
| NI_NUMERICSERV
);
209 strcpy(name_buf
, default_name
);
210 rprintf(FERROR
, RSYNC_NAME
": name lookup failed for %s: %s\n",
212 gai_strerror(name_err
));
222 * Compare an addrinfo from the resolver to a sockinfo.
224 * Like strcmp, returns 0 for identical.
226 int compare_addrinfo_sockaddr(const struct addrinfo
*ai
,
227 const struct sockaddr_storage
*ss
)
229 int ss_family
= get_sockaddr_family(ss
);
230 const char fn
[] = "compare_addrinfo_sockaddr";
232 if (ai
->ai_family
!= ss_family
) {
234 "%s: response family %d != %d\n",
235 fn
, ai
->ai_family
, ss_family
);
239 /* The comparison method depends on the particular AF. */
240 if (ss_family
== AF_INET
) {
241 const struct sockaddr_in
*sin1
, *sin2
;
243 sin1
= (const struct sockaddr_in
*) ss
;
244 sin2
= (const struct sockaddr_in
*) ai
->ai_addr
;
246 return memcmp(&sin1
->sin_addr
, &sin2
->sin_addr
,
247 sizeof sin1
->sin_addr
);
250 else if (ss_family
== AF_INET6
) {
251 const struct sockaddr_in6
*sin1
, *sin2
;
253 sin1
= (const struct sockaddr_in6
*) ss
;
254 sin2
= (const struct sockaddr_in6
*) ai
->ai_addr
;
256 return memcmp(&sin1
->sin6_addr
, &sin2
->sin6_addr
,
257 sizeof sin1
->sin6_addr
);
268 * Do a forward lookup on @p name_buf and make sure it corresponds to
269 * @p ss -- otherwise we may be being spoofed. If we suspect we are,
270 * then we don't abort the connection but just emit a warning, and
271 * change @p name_buf to be "UNKNOWN".
273 * We don't do anything with the service when checking the name,
274 * because it doesn't seem that it could be spoofed in any way, and
275 * getaddrinfo on random service names seems to cause problems on AIX.
277 int check_name(int fd
,
278 const struct sockaddr_storage
*ss
,
281 struct addrinfo hints
, *res
, *res0
;
283 int ss_family
= get_sockaddr_family(ss
);
285 memset(&hints
, 0, sizeof(hints
));
286 hints
.ai_family
= ss_family
;
287 hints
.ai_flags
= AI_CANONNAME
;
288 hints
.ai_socktype
= SOCK_STREAM
;
289 error
= getaddrinfo(name_buf
, NULL
, &hints
, &res0
);
292 RSYNC_NAME
": forward name lookup for %s failed: %s\n",
293 name_buf
, gai_strerror(error
));
294 strcpy(name_buf
, default_name
);
299 /* Given all these results, we expect that one of them will be
300 * the same as ss. The comparison is a bit complicated. */
301 for (res
= res0
; res
; res
= res
->ai_next
) {
302 if (!compare_addrinfo_sockaddr(res
, ss
))
303 break; /* OK, identical */
307 /* We hit the end of the list without finding an
308 * address that was the same as ss. */
309 rprintf(FERROR
, RSYNC_NAME
310 ": no known address for \"%s\": "
311 "spoofed address?\n",
313 strcpy(name_buf
, default_name
);
314 } else if (res
== NULL
) {
315 /* We hit the end of the list without finding an
316 * address that was the same as ss. */
317 rprintf(FERROR
, RSYNC_NAME
318 ": %s is not a known address for \"%s\": "
319 "spoofed address?\n",
322 strcpy(name_buf
, default_name
);