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0cd2f407 MP |
1 | /* -*- c-file-style: "linux" -*- |
2 | ||
3 | rsync -- fast file replication program | |
4 | ||
5 | Copyright (C) 1992-2001 by Andrew Tridgell <tridge@samba.org> | |
6 | Copyright (C) 2001, 2002 by Martin Pool <mbp@samba.org> | |
7 | ||
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. | |
12 | ||
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. | |
17 | ||
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 | |
25 | * | |
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 | /** | |
42 | * Return the IP addr of the client as a string | |
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 | ||
53 | if (initialised) return addr_buf; | |
54 | ||
55 | initialised = 1; | |
56 | ||
542ad675 DD |
57 | if (am_server) { |
58 | /* daemon over --rsh mode */ | |
59 | strcpy(addr_buf, "0.0.0.0"); | |
60 | if ((ssh_client = getenv("SSH_CLIENT")) != NULL) { | |
61 | /* truncate SSH_CLIENT to just IP address */ | |
62 | p = strchr(ssh_client, ' '); | |
63 | if (p) { | |
64 | len = MIN((unsigned int) (p - ssh_client), | |
65 | sizeof(addr_buf) - 1); | |
66 | strncpy(addr_buf, ssh_client, len); | |
67 | *(addr_buf + len) = '\0'; | |
68 | } | |
69 | } | |
3b5f6214 | 70 | } else { |
09021eab | 71 | client_sockaddr(fd, &ss, &length); |
3b5f6214 WD |
72 | getnameinfo((struct sockaddr *)&ss, length, |
73 | addr_buf, sizeof addr_buf, NULL, 0, NI_NUMERICHOST); | |
74 | } | |
09021eab | 75 | |
0cd2f407 MP |
76 | return addr_buf; |
77 | } | |
78 | ||
79 | ||
80 | static int get_sockaddr_family(const struct sockaddr_storage *ss) | |
81 | { | |
82 | return ((struct sockaddr *) ss)->sa_family; | |
83 | } | |
84 | ||
85 | ||
86 | /** | |
87 | * Return the DNS name of the client. | |
88 | * | |
89 | * The name is statically cached so that repeated lookups are quick, | |
90 | * so there is a limit of one lookup per customer. | |
91 | * | |
92 | * If anything goes wrong, including the name->addr->name check, then | |
93 | * we just use "UNKNOWN", so you can use that value in hosts allow | |
94 | * lines. | |
6c92af20 MP |
95 | * |
96 | * After translation from sockaddr to name we do a forward lookup to | |
97 | * make sure nobody is spoofing PTR records. | |
0cd2f407 MP |
98 | **/ |
99 | char *client_name(int fd) | |
100 | { | |
0cd2f407 MP |
101 | static char name_buf[100]; |
102 | static char port_buf[100]; | |
103 | static int initialised; | |
3b5f6214 WD |
104 | struct sockaddr_storage ss, *ssp; |
105 | struct sockaddr_in sin; | |
106 | #ifdef INET6 | |
107 | struct sockaddr_in6 sin6; | |
108 | #endif | |
1e736b8f | 109 | socklen_t ss_len; |
0cd2f407 MP |
110 | |
111 | if (initialised) return name_buf; | |
112 | ||
113 | strcpy(name_buf, default_name); | |
114 | initialised = 1; | |
115 | ||
542ad675 DD |
116 | if (am_server) { |
117 | /* daemon over --rsh mode */ | |
118 | ||
1e736b8f | 119 | char *addr = client_addr(fd); |
a6d8c3f3 | 120 | #ifdef INET6 |
1e736b8f DD |
121 | int dots = 0; |
122 | char *p; | |
1e736b8f | 123 | |
3b5f6214 | 124 | for (p = addr; *p && (dots <= 3); p++) { |
1e736b8f DD |
125 | if (*p == '.') |
126 | dots++; | |
127 | } | |
128 | if (dots > 3) { | |
129 | /* more than 4 parts to IP address, must be ipv6 */ | |
130 | ssp = (struct sockaddr_storage *) &sin6; | |
131 | ss_len = sizeof sin6; | |
132 | memset(ssp, 0, ss_len); | |
aaf375d0 | 133 | inet_pton(AF_INET6, addr, &sin6.sin6_addr); |
1e736b8f DD |
134 | sin6.sin6_family = AF_INET6; |
135 | } else | |
a6d8c3f3 | 136 | #endif |
1e736b8f DD |
137 | { |
138 | ssp = (struct sockaddr_storage *) &sin; | |
139 | ss_len = sizeof sin; | |
140 | memset(ssp, 0, ss_len); | |
aaf375d0 | 141 | inet_pton(AF_INET, addr, &sin.sin_addr); |
1e736b8f DD |
142 | sin.sin_family = AF_INET; |
143 | } | |
09021eab | 144 | |
09021eab | 145 | } else { |
1e736b8f DD |
146 | ss_len = sizeof ss; |
147 | ssp = &ss; | |
09021eab DD |
148 | |
149 | client_sockaddr(fd, &ss, &ss_len); | |
150 | ||
09021eab | 151 | } |
0cd2f407 | 152 | |
1e736b8f DD |
153 | if (!lookup_name(fd, ssp, ss_len, name_buf, sizeof name_buf, |
154 | port_buf, sizeof port_buf)) | |
155 | check_name(fd, ssp, name_buf); | |
156 | ||
0cd2f407 MP |
157 | return name_buf; |
158 | } | |
159 | ||
160 | ||
161 | ||
162 | /** | |
af32f69e MP |
163 | * Get the sockaddr for the client. |
164 | * | |
165 | * If it comes in as an ipv4 address mapped into IPv6 format then we | |
166 | * convert it back to a regular IPv4. | |
0cd2f407 MP |
167 | **/ |
168 | void client_sockaddr(int fd, | |
169 | struct sockaddr_storage *ss, | |
170 | socklen_t *ss_len) | |
171 | { | |
bc2b4963 DD |
172 | memset(ss, 0, sizeof(*ss)); |
173 | ||
0cd2f407 MP |
174 | if (getpeername(fd, (struct sockaddr *) ss, ss_len)) { |
175 | /* FIXME: Can we really not continue? */ | |
176 | rprintf(FERROR, RSYNC_NAME ": getpeername on fd%d failed: %s\n", | |
177 | fd, strerror(errno)); | |
178 | exit_cleanup(RERR_SOCKETIO); | |
179 | } | |
180 | ||
181 | #ifdef INET6 | |
182 | if (get_sockaddr_family(ss) == AF_INET6 && | |
183 | IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)ss)->sin6_addr)) { | |
184 | /* OK, so ss is in the IPv6 family, but it is really | |
185 | * an IPv4 address: something like | |
186 | * "::ffff:10.130.1.2". If we use it as-is, then the | |
187 | * reverse lookup might fail or perhaps something else | |
188 | * bad might happen. So instead we convert it to an | |
189 | * equivalent address in the IPv4 address family. */ | |
190 | struct sockaddr_in6 sin6; | |
191 | struct sockaddr_in *sin; | |
192 | ||
193 | memcpy(&sin6, ss, sizeof(sin6)); | |
194 | sin = (struct sockaddr_in *)ss; | |
195 | memset(sin, 0, sizeof(*sin)); | |
196 | sin->sin_family = AF_INET; | |
197 | *ss_len = sizeof(struct sockaddr_in); | |
ac7aa922 | 198 | #if HAVE_SOCKADDR_SIN_LEN |
0cd2f407 MP |
199 | sin->sin_len = *ss_len; |
200 | #endif | |
201 | sin->sin_port = sin6.sin6_port; | |
202 | ||
203 | /* There is a macro to extract the mapped part | |
204 | * (IN6_V4MAPPED_TO_SINADDR ?), but it does not seem | |
205 | * to be present in the Linux headers. */ | |
206 | memcpy(&sin->sin_addr, &sin6.sin6_addr.s6_addr[12], | |
207 | sizeof(sin->sin_addr)); | |
208 | } | |
209 | #endif | |
210 | } | |
211 | ||
212 | ||
213 | /** | |
214 | * Look up a name from @p ss into @p name_buf. | |
6c92af20 MP |
215 | * |
216 | * @param fd file descriptor for client socket. | |
0cd2f407 MP |
217 | **/ |
218 | int lookup_name(int fd, const struct sockaddr_storage *ss, | |
219 | socklen_t ss_len, | |
220 | char *name_buf, size_t name_buf_len, | |
221 | char *port_buf, size_t port_buf_len) | |
222 | { | |
223 | int name_err; | |
224 | ||
225 | /* reverse lookup */ | |
226 | name_err = getnameinfo((struct sockaddr *) ss, ss_len, | |
227 | name_buf, name_buf_len, | |
228 | port_buf, port_buf_len, | |
229 | NI_NAMEREQD | NI_NUMERICSERV); | |
230 | if (name_err != 0) { | |
231 | strcpy(name_buf, default_name); | |
232 | rprintf(FERROR, RSYNC_NAME ": name lookup failed for %s: %s\n", | |
233 | client_addr(fd), | |
234 | gai_strerror(name_err)); | |
235 | return name_err; | |
236 | } | |
237 | ||
238 | return 0; | |
239 | } | |
240 | ||
241 | ||
242 | ||
974f27e7 MP |
243 | /** |
244 | * Compare an addrinfo from the resolver to a sockinfo. | |
245 | * | |
246 | * Like strcmp, returns 0 for identical. | |
247 | **/ | |
248 | int compare_addrinfo_sockaddr(const struct addrinfo *ai, | |
249 | const struct sockaddr_storage *ss) | |
250 | { | |
251 | int ss_family = get_sockaddr_family(ss); | |
252 | const char fn[] = "compare_addrinfo_sockaddr"; | |
253 | ||
254 | if (ai->ai_family != ss_family) { | |
255 | rprintf(FERROR, | |
256 | "%s: response family %d != %d\n", | |
257 | fn, ai->ai_family, ss_family); | |
258 | return 1; | |
259 | } | |
260 | ||
39e01d2d MP |
261 | /* The comparison method depends on the particular AF. */ |
262 | if (ss_family == AF_INET) { | |
263 | const struct sockaddr_in *sin1, *sin2; | |
264 | ||
265 | sin1 = (const struct sockaddr_in *) ss; | |
266 | sin2 = (const struct sockaddr_in *) ai->ai_addr; | |
267 | ||
6780f720 MP |
268 | return memcmp(&sin1->sin_addr, &sin2->sin_addr, |
269 | sizeof sin1->sin_addr); | |
39e01d2d | 270 | } |
974f27e7 | 271 | #ifdef INET6 |
39e01d2d | 272 | else if (ss_family == AF_INET6) { |
6780f720 MP |
273 | const struct sockaddr_in6 *sin1, *sin2; |
274 | ||
275 | sin1 = (const struct sockaddr_in6 *) ss; | |
276 | sin2 = (const struct sockaddr_in6 *) ai->ai_addr; | |
bc2b4963 DD |
277 | |
278 | if (ai->ai_addrlen < sizeof(struct sockaddr_in6)) { | |
279 | rprintf(FERROR, | |
280 | "%s: too short sockaddr_in6; length=%d\n", | |
281 | fn, ai->ai_addrlen); | |
282 | return 1; | |
283 | } | |
284 | ||
285 | if (memcmp(&sin1->sin6_addr, &sin2->sin6_addr, | |
286 | sizeof sin1->sin6_addr)) | |
287 | return 1; | |
288 | ||
289 | #ifdef HAVE_SOCKADDR_IN6_SCOPE_ID | |
290 | if (sin1->sin6_scope_id != sin2->sin6_scope_id) | |
291 | return 1; | |
292 | #endif | |
293 | return 0; | |
39e01d2d MP |
294 | } |
295 | #endif /* INET6 */ | |
296 | else { | |
297 | /* don't know */ | |
974f27e7 MP |
298 | return 1; |
299 | } | |
300 | } | |
301 | ||
302 | ||
af32f69e MP |
303 | /** |
304 | * Do a forward lookup on @p name_buf and make sure it corresponds to | |
305 | * @p ss -- otherwise we may be being spoofed. If we suspect we are, | |
306 | * then we don't abort the connection but just emit a warning, and | |
307 | * change @p name_buf to be "UNKNOWN". | |
6c92af20 MP |
308 | * |
309 | * We don't do anything with the service when checking the name, | |
310 | * because it doesn't seem that it could be spoofed in any way, and | |
311 | * getaddrinfo on random service names seems to cause problems on AIX. | |
af32f69e | 312 | **/ |
0cd2f407 MP |
313 | int check_name(int fd, |
314 | const struct sockaddr_storage *ss, | |
6c92af20 | 315 | char *name_buf) |
0cd2f407 MP |
316 | { |
317 | struct addrinfo hints, *res, *res0; | |
318 | int error; | |
319 | int ss_family = get_sockaddr_family(ss); | |
320 | ||
321 | memset(&hints, 0, sizeof(hints)); | |
39e01d2d MP |
322 | hints.ai_family = ss_family; |
323 | hints.ai_flags = AI_CANONNAME; | |
0cd2f407 | 324 | hints.ai_socktype = SOCK_STREAM; |
6c92af20 | 325 | error = getaddrinfo(name_buf, NULL, &hints, &res0); |
0cd2f407 MP |
326 | if (error) { |
327 | rprintf(FERROR, | |
af32f69e MP |
328 | RSYNC_NAME ": forward name lookup for %s failed: %s\n", |
329 | name_buf, gai_strerror(error)); | |
0cd2f407 MP |
330 | strcpy(name_buf, default_name); |
331 | return error; | |
332 | } | |
333 | ||
334 | ||
974f27e7 MP |
335 | /* Given all these results, we expect that one of them will be |
336 | * the same as ss. The comparison is a bit complicated. */ | |
0cd2f407 | 337 | for (res = res0; res; res = res->ai_next) { |
974f27e7 MP |
338 | if (!compare_addrinfo_sockaddr(res, ss)) |
339 | break; /* OK, identical */ | |
0cd2f407 MP |
340 | } |
341 | ||
342 | if (!res0) { | |
343 | /* We hit the end of the list without finding an | |
344 | * address that was the same as ss. */ | |
345 | rprintf(FERROR, RSYNC_NAME | |
346 | ": no known address for \"%s\": " | |
347 | "spoofed address?\n", | |
348 | name_buf); | |
349 | strcpy(name_buf, default_name); | |
974f27e7 | 350 | } else if (res == NULL) { |
0cd2f407 MP |
351 | /* We hit the end of the list without finding an |
352 | * address that was the same as ss. */ | |
353 | rprintf(FERROR, RSYNC_NAME | |
354 | ": %s is not a known address for \"%s\": " | |
355 | "spoofed address?\n", | |
356 | client_addr(fd), | |
357 | name_buf); | |
358 | strcpy(name_buf, default_name); | |
359 | } | |
360 | ||
361 | freeaddrinfo(res0); | |
362 | return 0; | |
363 | } | |
364 |