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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
;
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 char *client_name(int fd
)
80 struct sockaddr_storage ss
;
81 socklen_t ss_len
= sizeof ss
;
82 static char name_buf
[100];
83 static char port_buf
[100];
84 static int initialised
;
86 if (initialised
) return name_buf
;
88 strcpy(name_buf
, default_name
);
91 client_sockaddr(fd
, &ss
, &ss_len
);
93 if (!lookup_name(fd
, &ss
, ss_len
, name_buf
, sizeof name_buf
, port_buf
, sizeof port_buf
))
94 check_name(fd
, &ss
, ss_len
, name_buf
, port_buf
);
102 * Get the sockaddr for the client.
104 void client_sockaddr(int fd
,
105 struct sockaddr_storage
*ss
,
108 if (getpeername(fd
, (struct sockaddr
*) ss
, ss_len
)) {
109 /* FIXME: Can we really not continue? */
110 rprintf(FERROR
, RSYNC_NAME
": getpeername on fd%d failed: %s\n",
111 fd
, strerror(errno
));
112 exit_cleanup(RERR_SOCKETIO
);
116 if (get_sockaddr_family(ss
) == AF_INET6
&&
117 IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6
*)ss
)->sin6_addr
)) {
118 /* OK, so ss is in the IPv6 family, but it is really
119 * an IPv4 address: something like
120 * "::ffff:10.130.1.2". If we use it as-is, then the
121 * reverse lookup might fail or perhaps something else
122 * bad might happen. So instead we convert it to an
123 * equivalent address in the IPv4 address family. */
124 struct sockaddr_in6 sin6
;
125 struct sockaddr_in
*sin
;
127 memcpy(&sin6
, ss
, sizeof(sin6
));
128 sin
= (struct sockaddr_in
*)ss
;
129 memset(sin
, 0, sizeof(*sin
));
130 sin
->sin_family
= AF_INET
;
131 *ss_len
= sizeof(struct sockaddr_in
);
132 #ifdef HAVE_SOCKADDR_LEN
133 sin
->sin_len
= *ss_len
;
135 sin
->sin_port
= sin6
.sin6_port
;
137 /* There is a macro to extract the mapped part
138 * (IN6_V4MAPPED_TO_SINADDR ?), but it does not seem
139 * to be present in the Linux headers. */
140 memcpy(&sin
->sin_addr
, &sin6
.sin6_addr
.s6_addr
[12],
141 sizeof(sin
->sin_addr
));
148 * Look up a name from @p ss into @p name_buf.
150 int lookup_name(int fd
, const struct sockaddr_storage
*ss
,
152 char *name_buf
, size_t name_buf_len
,
153 char *port_buf
, size_t port_buf_len
)
158 name_err
= getnameinfo((struct sockaddr
*) ss
, ss_len
,
159 name_buf
, name_buf_len
,
160 port_buf
, port_buf_len
,
161 NI_NAMEREQD
| NI_NUMERICSERV
);
163 strcpy(name_buf
, default_name
);
164 rprintf(FERROR
, RSYNC_NAME
": name lookup failed for %s: %s\n",
166 gai_strerror(name_err
));
175 /* Do a forward lookup on name_buf and make sure it corresponds to ss
176 * -- otherwise we may be being spoofed. If we suspect we are, then
177 * we don't abort the connection but just emit a warning. */
178 int check_name(int fd
,
179 const struct sockaddr_storage
*ss
,
182 const char *port_buf
)
184 struct addrinfo hints
, *res
, *res0
;
186 int ss_family
= get_sockaddr_family(ss
);
188 memset(&hints
, 0, sizeof(hints
));
189 hints
.ai_family
= PF_UNSPEC
;
190 hints
.ai_flags
= ss_family
;
191 hints
.ai_socktype
= SOCK_STREAM
;
192 error
= getaddrinfo(name_buf
, port_buf
, &hints
, &res0
);
195 RSYNC_NAME
": forward name lookup for %s:%s failed: %s\n",
197 gai_strerror(error
));
198 strcpy(name_buf
, default_name
);
203 /* We expect that one of the results will be the same as ss. */
204 for (res
= res0
; res
; res
= res
->ai_next
) {
205 if (res
->ai_family
!= ss_family
) {
207 "check_name: response family %d != %d\n",
208 res
->ai_family
, ss_family
);
211 if (res
->ai_addrlen
!= ss_len
) {
213 "check_name: addrlen %d != %d\n",
214 res
->ai_addrlen
, ss_len
);
217 if (memcmp(res
->ai_addr
, ss
, res
->ai_addrlen
) == 0) {
219 "check_name: %d bytes of address identical\n",
224 "check_name: %d bytes of address NOT identical\n",
230 /* We hit the end of the list without finding an
231 * address that was the same as ss. */
232 rprintf(FERROR
, RSYNC_NAME
233 ": no known address for \"%s\": "
234 "spoofed address?\n",
236 strcpy(name_buf
, default_name
);
239 /* We hit the end of the list without finding an
240 * address that was the same as ss. */
241 rprintf(FERROR
, RSYNC_NAME
242 ": %s is not a known address for \"%s\": "
243 "spoofed address?\n",
246 strcpy(name_buf
, default_name
);