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0cd2f407 | 1 | /* -*- c-file-style: "linux" -*- |
c1e7217f | 2 | |
0cd2f407 | 3 | rsync -- fast file replication program |
c1e7217f | 4 | |
0cd2f407 MP |
5 | Copyright (C) 1992-2001 by Andrew Tridgell <tridge@samba.org> |
6 | Copyright (C) 2001, 2002 by Martin Pool <mbp@samba.org> | |
c1e7217f | 7 | |
0cd2f407 MP |
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. | |
c1e7217f | 12 | |
0cd2f407 MP |
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. | |
c1e7217f | 17 | |
0cd2f407 MP |
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. | |
21 | */ | |
22 | ||
23 | /** | |
24 | * @file clientname.c | |
c1e7217f | 25 | * |
0cd2f407 MP |
26 | * Functions for looking up the remote name or addr of a socket. |
27 | * | |
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. | |
32 | **/ | |
33 | ||
34 | #include "rsync.h" | |
35 | ||
36 | static const char default_name[] = "UNKNOWN"; | |
542ad675 DD |
37 | extern int am_daemon; |
38 | extern int am_server; | |
0cd2f407 MP |
39 | |
40 | ||
41 | /** | |
c1e7217f | 42 | * Return the IP addr of the client as a string |
0cd2f407 MP |
43 | **/ |
44 | char *client_addr(int fd) | |
45 | { | |
46 | struct sockaddr_storage ss; | |
47 | socklen_t length = sizeof ss; | |
09021eab | 48 | char *ssh_client, *p; |
542ad675 | 49 | int len; |
0cd2f407 MP |
50 | static char addr_buf[100]; |
51 | static int initialised; | |
52 | ||
4cfa6156 WD |
53 | if (initialised) |
54 | return addr_buf; | |
0cd2f407 MP |
55 | |
56 | initialised = 1; | |
57 | ||
706c7530 | 58 | if (am_server) { /* daemon over --rsh mode */ |
542ad675 DD |
59 | strcpy(addr_buf, "0.0.0.0"); |
60 | if ((ssh_client = getenv("SSH_CLIENT")) != NULL) { | |
61 | /* truncate SSH_CLIENT to just IP address */ | |
2b284ee3 | 62 | if ((p = strchr(ssh_client, ' ')) != NULL) { |
c1e7217f WD |
63 | len = MIN((unsigned int) (p - ssh_client), |
64 | sizeof addr_buf - 1); | |
542ad675 DD |
65 | strncpy(addr_buf, ssh_client, len); |
66 | *(addr_buf + len) = '\0'; | |
67 | } | |
68 | } | |
3b5f6214 | 69 | } else { |
09021eab | 70 | client_sockaddr(fd, &ss, &length); |
3b5f6214 WD |
71 | getnameinfo((struct sockaddr *)&ss, length, |
72 | addr_buf, sizeof addr_buf, NULL, 0, NI_NUMERICHOST); | |
73 | } | |
09021eab | 74 | |
0cd2f407 MP |
75 | return addr_buf; |
76 | } | |
77 | ||
78 | ||
79 | static int get_sockaddr_family(const struct sockaddr_storage *ss) | |
80 | { | |
81 | return ((struct sockaddr *) ss)->sa_family; | |
82 | } | |
83 | ||
84 | ||
85 | /** | |
86 | * Return the DNS name of the client. | |
87 | * | |
88 | * The name is statically cached so that repeated lookups are quick, | |
89 | * so there is a limit of one lookup per customer. | |
90 | * | |
91 | * If anything goes wrong, including the name->addr->name check, then | |
92 | * we just use "UNKNOWN", so you can use that value in hosts allow | |
93 | * lines. | |
6c92af20 MP |
94 | * |
95 | * After translation from sockaddr to name we do a forward lookup to | |
96 | * make sure nobody is spoofing PTR records. | |
0cd2f407 MP |
97 | **/ |
98 | char *client_name(int fd) | |
99 | { | |
0cd2f407 MP |
100 | static char name_buf[100]; |
101 | static char port_buf[100]; | |
102 | static int initialised; | |
706c7530 | 103 | struct sockaddr_storage ss; |
1e736b8f | 104 | socklen_t ss_len; |
0cd2f407 | 105 | |
4cfa6156 WD |
106 | if (initialised) |
107 | return name_buf; | |
0cd2f407 MP |
108 | |
109 | strcpy(name_buf, default_name); | |
110 | initialised = 1; | |
111 | ||
706c7530 WD |
112 | memset(&ss, 0, sizeof ss); |
113 | ||
2b284ee3 | 114 | if (am_server) { /* daemon over --rsh mode */ |
1e736b8f | 115 | char *addr = client_addr(fd); |
706c7530 WD |
116 | struct addrinfo hint, *answer; |
117 | int err; | |
1e736b8f | 118 | |
706c7530 WD |
119 | memset(&hint, 0, sizeof hint); |
120 | ||
6a6d2113 | 121 | #ifdef AI_NUMERICHOST |
706c7530 | 122 | hint.ai_flags = AI_NUMERICHOST; |
6a6d2113 | 123 | #endif |
706c7530 WD |
124 | hint.ai_socktype = SOCK_STREAM; |
125 | ||
126 | if ((err = getaddrinfo(addr, NULL, &hint, &answer)) != 0) { | |
127 | rprintf(FERROR, RSYNC_NAME ": malformed address %s: %s\n", | |
128 | addr, gai_strerror(err)); | |
129 | return name_buf; | |
1e736b8f | 130 | } |
706c7530 WD |
131 | |
132 | switch (answer->ai_family) { | |
133 | case AF_INET: | |
134 | ss_len = sizeof (struct sockaddr_in); | |
135 | memcpy(&ss, answer->ai_addr, ss_len); | |
136 | break; | |
137 | #ifdef INET6 | |
138 | case AF_INET6: | |
139 | ss_len = sizeof (struct sockaddr_in6); | |
140 | memcpy(&ss, answer->ai_addr, ss_len); | |
141 | break; | |
a6d8c3f3 | 142 | #endif |
1e736b8f | 143 | } |
706c7530 | 144 | freeaddrinfo(answer); |
09021eab | 145 | } else { |
1e736b8f | 146 | ss_len = sizeof ss; |
09021eab | 147 | client_sockaddr(fd, &ss, &ss_len); |
09021eab | 148 | } |
0cd2f407 | 149 | |
706c7530 | 150 | if (!lookup_name(fd, &ss, ss_len, name_buf, sizeof name_buf, |
1e736b8f | 151 | port_buf, sizeof port_buf)) |
706c7530 | 152 | check_name(fd, &ss, name_buf); |
1e736b8f | 153 | |
0cd2f407 MP |
154 | return name_buf; |
155 | } | |
156 | ||
157 | ||
158 | ||
159 | /** | |
af32f69e MP |
160 | * Get the sockaddr for the client. |
161 | * | |
162 | * If it comes in as an ipv4 address mapped into IPv6 format then we | |
163 | * convert it back to a regular IPv4. | |
0cd2f407 MP |
164 | **/ |
165 | void client_sockaddr(int fd, | |
166 | struct sockaddr_storage *ss, | |
167 | socklen_t *ss_len) | |
168 | { | |
c1e7217f | 169 | memset(ss, 0, sizeof *ss); |
bc2b4963 | 170 | |
0cd2f407 MP |
171 | if (getpeername(fd, (struct sockaddr *) ss, ss_len)) { |
172 | /* FIXME: Can we really not continue? */ | |
173 | rprintf(FERROR, RSYNC_NAME ": getpeername on fd%d failed: %s\n", | |
174 | fd, strerror(errno)); | |
175 | exit_cleanup(RERR_SOCKETIO); | |
176 | } | |
177 | ||
178 | #ifdef INET6 | |
2b284ee3 | 179 | if (get_sockaddr_family(ss) == AF_INET6 && |
0cd2f407 MP |
180 | IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)ss)->sin6_addr)) { |
181 | /* OK, so ss is in the IPv6 family, but it is really | |
182 | * an IPv4 address: something like | |
183 | * "::ffff:10.130.1.2". If we use it as-is, then the | |
184 | * reverse lookup might fail or perhaps something else | |
185 | * bad might happen. So instead we convert it to an | |
186 | * equivalent address in the IPv4 address family. */ | |
187 | struct sockaddr_in6 sin6; | |
188 | struct sockaddr_in *sin; | |
189 | ||
c1e7217f | 190 | memcpy(&sin6, ss, sizeof sin6); |
0cd2f407 | 191 | sin = (struct sockaddr_in *)ss; |
c1e7217f | 192 | memset(sin, 0, sizeof *sin); |
0cd2f407 | 193 | sin->sin_family = AF_INET; |
c1e7217f | 194 | *ss_len = sizeof (struct sockaddr_in); |
16f72adc | 195 | #if HAVE_SOCKADDR_IN_LEN |
0cd2f407 MP |
196 | sin->sin_len = *ss_len; |
197 | #endif | |
198 | sin->sin_port = sin6.sin6_port; | |
199 | ||
200 | /* There is a macro to extract the mapped part | |
201 | * (IN6_V4MAPPED_TO_SINADDR ?), but it does not seem | |
202 | * to be present in the Linux headers. */ | |
203 | memcpy(&sin->sin_addr, &sin6.sin6_addr.s6_addr[12], | |
c1e7217f | 204 | sizeof sin->sin_addr); |
2b284ee3 | 205 | } |
0cd2f407 MP |
206 | #endif |
207 | } | |
208 | ||
209 | ||
210 | /** | |
211 | * Look up a name from @p ss into @p name_buf. | |
6c92af20 MP |
212 | * |
213 | * @param fd file descriptor for client socket. | |
0cd2f407 MP |
214 | **/ |
215 | int lookup_name(int fd, const struct sockaddr_storage *ss, | |
216 | socklen_t ss_len, | |
217 | char *name_buf, size_t name_buf_len, | |
218 | char *port_buf, size_t port_buf_len) | |
219 | { | |
220 | int name_err; | |
4cfa6156 | 221 | |
0cd2f407 MP |
222 | /* reverse lookup */ |
223 | name_err = getnameinfo((struct sockaddr *) ss, ss_len, | |
224 | name_buf, name_buf_len, | |
225 | port_buf, port_buf_len, | |
226 | NI_NAMEREQD | NI_NUMERICSERV); | |
227 | if (name_err != 0) { | |
228 | strcpy(name_buf, default_name); | |
229 | rprintf(FERROR, RSYNC_NAME ": name lookup failed for %s: %s\n", | |
230 | client_addr(fd), | |
231 | gai_strerror(name_err)); | |
232 | return name_err; | |
233 | } | |
234 | ||
235 | return 0; | |
236 | } | |
237 | ||
238 | ||
239 | ||
974f27e7 MP |
240 | /** |
241 | * Compare an addrinfo from the resolver to a sockinfo. | |
242 | * | |
243 | * Like strcmp, returns 0 for identical. | |
244 | **/ | |
245 | int compare_addrinfo_sockaddr(const struct addrinfo *ai, | |
246 | const struct sockaddr_storage *ss) | |
247 | { | |
248 | int ss_family = get_sockaddr_family(ss); | |
249 | const char fn[] = "compare_addrinfo_sockaddr"; | |
c1e7217f | 250 | |
974f27e7 MP |
251 | if (ai->ai_family != ss_family) { |
252 | rprintf(FERROR, | |
253 | "%s: response family %d != %d\n", | |
254 | fn, ai->ai_family, ss_family); | |
255 | return 1; | |
256 | } | |
257 | ||
39e01d2d MP |
258 | /* The comparison method depends on the particular AF. */ |
259 | if (ss_family == AF_INET) { | |
260 | const struct sockaddr_in *sin1, *sin2; | |
261 | ||
262 | sin1 = (const struct sockaddr_in *) ss; | |
263 | sin2 = (const struct sockaddr_in *) ai->ai_addr; | |
4cfa6156 | 264 | |
6780f720 MP |
265 | return memcmp(&sin1->sin_addr, &sin2->sin_addr, |
266 | sizeof sin1->sin_addr); | |
39e01d2d | 267 | } |
2b284ee3 | 268 | |
974f27e7 | 269 | #ifdef INET6 |
2b284ee3 | 270 | if (ss_family == AF_INET6) { |
6780f720 MP |
271 | const struct sockaddr_in6 *sin1, *sin2; |
272 | ||
273 | sin1 = (const struct sockaddr_in6 *) ss; | |
274 | sin2 = (const struct sockaddr_in6 *) ai->ai_addr; | |
bc2b4963 | 275 | |
c1e7217f | 276 | if (ai->ai_addrlen < sizeof (struct sockaddr_in6)) { |
bc2b4963 DD |
277 | rprintf(FERROR, |
278 | "%s: too short sockaddr_in6; length=%d\n", | |
279 | fn, ai->ai_addrlen); | |
280 | return 1; | |
281 | } | |
282 | ||
283 | if (memcmp(&sin1->sin6_addr, &sin2->sin6_addr, | |
284 | sizeof sin1->sin6_addr)) | |
285 | return 1; | |
286 | ||
287 | #ifdef HAVE_SOCKADDR_IN6_SCOPE_ID | |
288 | if (sin1->sin6_scope_id != sin2->sin6_scope_id) | |
289 | return 1; | |
290 | #endif | |
291 | return 0; | |
39e01d2d MP |
292 | } |
293 | #endif /* INET6 */ | |
2b284ee3 WD |
294 | |
295 | /* don't know */ | |
296 | return 1; | |
974f27e7 MP |
297 | } |
298 | ||
299 | ||
af32f69e MP |
300 | /** |
301 | * Do a forward lookup on @p name_buf and make sure it corresponds to | |
302 | * @p ss -- otherwise we may be being spoofed. If we suspect we are, | |
303 | * then we don't abort the connection but just emit a warning, and | |
304 | * change @p name_buf to be "UNKNOWN". | |
6c92af20 MP |
305 | * |
306 | * We don't do anything with the service when checking the name, | |
307 | * because it doesn't seem that it could be spoofed in any way, and | |
308 | * getaddrinfo on random service names seems to cause problems on AIX. | |
af32f69e | 309 | **/ |
0cd2f407 MP |
310 | int check_name(int fd, |
311 | const struct sockaddr_storage *ss, | |
6c92af20 | 312 | char *name_buf) |
0cd2f407 MP |
313 | { |
314 | struct addrinfo hints, *res, *res0; | |
315 | int error; | |
316 | int ss_family = get_sockaddr_family(ss); | |
317 | ||
c1e7217f | 318 | memset(&hints, 0, sizeof hints); |
39e01d2d MP |
319 | hints.ai_family = ss_family; |
320 | hints.ai_flags = AI_CANONNAME; | |
0cd2f407 | 321 | hints.ai_socktype = SOCK_STREAM; |
6c92af20 | 322 | error = getaddrinfo(name_buf, NULL, &hints, &res0); |
0cd2f407 MP |
323 | if (error) { |
324 | rprintf(FERROR, | |
af32f69e MP |
325 | RSYNC_NAME ": forward name lookup for %s failed: %s\n", |
326 | name_buf, gai_strerror(error)); | |
0cd2f407 MP |
327 | strcpy(name_buf, default_name); |
328 | return error; | |
329 | } | |
330 | ||
331 | ||
974f27e7 MP |
332 | /* Given all these results, we expect that one of them will be |
333 | * the same as ss. The comparison is a bit complicated. */ | |
0cd2f407 | 334 | for (res = res0; res; res = res->ai_next) { |
974f27e7 MP |
335 | if (!compare_addrinfo_sockaddr(res, ss)) |
336 | break; /* OK, identical */ | |
0cd2f407 MP |
337 | } |
338 | ||
339 | if (!res0) { | |
340 | /* We hit the end of the list without finding an | |
341 | * address that was the same as ss. */ | |
342 | rprintf(FERROR, RSYNC_NAME | |
343 | ": no known address for \"%s\": " | |
344 | "spoofed address?\n", | |
345 | name_buf); | |
346 | strcpy(name_buf, default_name); | |
974f27e7 | 347 | } else if (res == NULL) { |
0cd2f407 MP |
348 | /* We hit the end of the list without finding an |
349 | * address that was the same as ss. */ | |
350 | rprintf(FERROR, RSYNC_NAME | |
351 | ": %s is not a known address for \"%s\": " | |
352 | "spoofed address?\n", | |
353 | client_addr(fd), | |
354 | name_buf); | |
355 | strcpy(name_buf, default_name); | |
356 | } | |
357 | ||
358 | freeaddrinfo(res0); | |
359 | return 0; | |
360 | } | |
361 |