Commit | Line | Data |
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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 | { | |
0cd2f407 MP |
46 | static char addr_buf[100]; |
47 | static int initialised; | |
b2ef4f61 WD |
48 | struct sockaddr_storage ss; |
49 | socklen_t length = sizeof ss; | |
50 | char *ssh_info, *p; | |
0cd2f407 | 51 | |
4cfa6156 WD |
52 | if (initialised) |
53 | return addr_buf; | |
0cd2f407 MP |
54 | |
55 | initialised = 1; | |
56 | ||
706c7530 | 57 | if (am_server) { /* daemon over --rsh mode */ |
542ad675 | 58 | strcpy(addr_buf, "0.0.0.0"); |
b2ef4f61 WD |
59 | if ((ssh_info = getenv("SSH_CONNECTION")) != NULL |
60 | || (ssh_info = getenv("SSH_CLIENT")) != NULL | |
61 | || (ssh_info = getenv("SSH2_CLIENT")) != NULL) { | |
62 | strlcpy(addr_buf, ssh_info, sizeof addr_buf); | |
63 | /* Truncate the value to just the IP address. */ | |
64 | if ((p = strchr(addr_buf, ' ')) != NULL) | |
65 | *p = '\0'; | |
542ad675 | 66 | } |
3b5f6214 | 67 | } else { |
09021eab | 68 | client_sockaddr(fd, &ss, &length); |
3b5f6214 WD |
69 | getnameinfo((struct sockaddr *)&ss, length, |
70 | addr_buf, sizeof addr_buf, NULL, 0, NI_NUMERICHOST); | |
71 | } | |
09021eab | 72 | |
0cd2f407 MP |
73 | return addr_buf; |
74 | } | |
75 | ||
76 | ||
77 | static int get_sockaddr_family(const struct sockaddr_storage *ss) | |
78 | { | |
79 | return ((struct sockaddr *) ss)->sa_family; | |
80 | } | |
81 | ||
82 | ||
83 | /** | |
84 | * Return the DNS name of the client. | |
85 | * | |
86 | * The name is statically cached so that repeated lookups are quick, | |
87 | * so there is a limit of one lookup per customer. | |
88 | * | |
89 | * If anything goes wrong, including the name->addr->name check, then | |
90 | * we just use "UNKNOWN", so you can use that value in hosts allow | |
91 | * lines. | |
6c92af20 MP |
92 | * |
93 | * After translation from sockaddr to name we do a forward lookup to | |
94 | * make sure nobody is spoofing PTR records. | |
0cd2f407 MP |
95 | **/ |
96 | char *client_name(int fd) | |
97 | { | |
0cd2f407 MP |
98 | static char name_buf[100]; |
99 | static char port_buf[100]; | |
100 | static int initialised; | |
706c7530 | 101 | struct sockaddr_storage ss; |
1e736b8f | 102 | socklen_t ss_len; |
0cd2f407 | 103 | |
4cfa6156 WD |
104 | if (initialised) |
105 | return name_buf; | |
0cd2f407 MP |
106 | |
107 | strcpy(name_buf, default_name); | |
108 | initialised = 1; | |
109 | ||
706c7530 WD |
110 | memset(&ss, 0, sizeof ss); |
111 | ||
2b284ee3 | 112 | if (am_server) { /* daemon over --rsh mode */ |
1e736b8f | 113 | char *addr = client_addr(fd); |
706c7530 WD |
114 | struct addrinfo hint, *answer; |
115 | int err; | |
1e736b8f | 116 | |
706c7530 WD |
117 | memset(&hint, 0, sizeof hint); |
118 | ||
6a6d2113 | 119 | #ifdef AI_NUMERICHOST |
706c7530 | 120 | hint.ai_flags = AI_NUMERICHOST; |
6a6d2113 | 121 | #endif |
706c7530 WD |
122 | hint.ai_socktype = SOCK_STREAM; |
123 | ||
124 | if ((err = getaddrinfo(addr, NULL, &hint, &answer)) != 0) { | |
fde045cd | 125 | rprintf(FLOG, "malformed address %s: %s\n", |
706c7530 WD |
126 | addr, gai_strerror(err)); |
127 | return name_buf; | |
1e736b8f | 128 | } |
706c7530 WD |
129 | |
130 | switch (answer->ai_family) { | |
131 | case AF_INET: | |
132 | ss_len = sizeof (struct sockaddr_in); | |
133 | memcpy(&ss, answer->ai_addr, ss_len); | |
134 | break; | |
25ff0441 | 135 | #if INET6 |
706c7530 WD |
136 | case AF_INET6: |
137 | ss_len = sizeof (struct sockaddr_in6); | |
138 | memcpy(&ss, answer->ai_addr, ss_len); | |
139 | break; | |
a6d8c3f3 | 140 | #endif |
1e736b8f | 141 | } |
706c7530 | 142 | freeaddrinfo(answer); |
09021eab | 143 | } else { |
1e736b8f | 144 | ss_len = sizeof ss; |
09021eab | 145 | client_sockaddr(fd, &ss, &ss_len); |
09021eab | 146 | } |
0cd2f407 | 147 | |
fde045cd WD |
148 | if (lookup_name(fd, &ss, ss_len, name_buf, sizeof name_buf, |
149 | port_buf, sizeof port_buf) == 0) | |
706c7530 | 150 | check_name(fd, &ss, name_buf); |
1e736b8f | 151 | |
0cd2f407 MP |
152 | return name_buf; |
153 | } | |
154 | ||
155 | ||
156 | ||
157 | /** | |
af32f69e MP |
158 | * Get the sockaddr for the client. |
159 | * | |
160 | * If it comes in as an ipv4 address mapped into IPv6 format then we | |
161 | * convert it back to a regular IPv4. | |
0cd2f407 MP |
162 | **/ |
163 | void client_sockaddr(int fd, | |
164 | struct sockaddr_storage *ss, | |
165 | socklen_t *ss_len) | |
166 | { | |
c1e7217f | 167 | memset(ss, 0, sizeof *ss); |
bc2b4963 | 168 | |
0cd2f407 MP |
169 | if (getpeername(fd, (struct sockaddr *) ss, ss_len)) { |
170 | /* FIXME: Can we really not continue? */ | |
fde045cd | 171 | rsyserr(FLOG, errno, "getpeername on fd%d failed", fd); |
0cd2f407 MP |
172 | exit_cleanup(RERR_SOCKETIO); |
173 | } | |
174 | ||
25ff0441 | 175 | #if INET6 |
2b284ee3 | 176 | if (get_sockaddr_family(ss) == AF_INET6 && |
0cd2f407 MP |
177 | IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)ss)->sin6_addr)) { |
178 | /* OK, so ss is in the IPv6 family, but it is really | |
179 | * an IPv4 address: something like | |
180 | * "::ffff:10.130.1.2". If we use it as-is, then the | |
181 | * reverse lookup might fail or perhaps something else | |
182 | * bad might happen. So instead we convert it to an | |
183 | * equivalent address in the IPv4 address family. */ | |
184 | struct sockaddr_in6 sin6; | |
185 | struct sockaddr_in *sin; | |
186 | ||
c1e7217f | 187 | memcpy(&sin6, ss, sizeof sin6); |
0cd2f407 | 188 | sin = (struct sockaddr_in *)ss; |
c1e7217f | 189 | memset(sin, 0, sizeof *sin); |
0cd2f407 | 190 | sin->sin_family = AF_INET; |
c1e7217f | 191 | *ss_len = sizeof (struct sockaddr_in); |
16f72adc | 192 | #if HAVE_SOCKADDR_IN_LEN |
0cd2f407 MP |
193 | sin->sin_len = *ss_len; |
194 | #endif | |
195 | sin->sin_port = sin6.sin6_port; | |
196 | ||
197 | /* There is a macro to extract the mapped part | |
198 | * (IN6_V4MAPPED_TO_SINADDR ?), but it does not seem | |
199 | * to be present in the Linux headers. */ | |
200 | memcpy(&sin->sin_addr, &sin6.sin6_addr.s6_addr[12], | |
c1e7217f | 201 | sizeof sin->sin_addr); |
2b284ee3 | 202 | } |
0cd2f407 MP |
203 | #endif |
204 | } | |
205 | ||
206 | ||
207 | /** | |
208 | * Look up a name from @p ss into @p name_buf. | |
6c92af20 MP |
209 | * |
210 | * @param fd file descriptor for client socket. | |
0cd2f407 MP |
211 | **/ |
212 | int lookup_name(int fd, const struct sockaddr_storage *ss, | |
213 | socklen_t ss_len, | |
214 | char *name_buf, size_t name_buf_len, | |
215 | char *port_buf, size_t port_buf_len) | |
216 | { | |
217 | int name_err; | |
4cfa6156 | 218 | |
0cd2f407 MP |
219 | /* reverse lookup */ |
220 | name_err = getnameinfo((struct sockaddr *) ss, ss_len, | |
221 | name_buf, name_buf_len, | |
222 | port_buf, port_buf_len, | |
223 | NI_NAMEREQD | NI_NUMERICSERV); | |
224 | if (name_err != 0) { | |
225 | strcpy(name_buf, default_name); | |
fde045cd WD |
226 | rprintf(FLOG, "name lookup failed for %s: %s\n", |
227 | client_addr(fd), gai_strerror(name_err)); | |
0cd2f407 MP |
228 | return name_err; |
229 | } | |
230 | ||
231 | return 0; | |
232 | } | |
233 | ||
234 | ||
235 | ||
974f27e7 MP |
236 | /** |
237 | * Compare an addrinfo from the resolver to a sockinfo. | |
238 | * | |
239 | * Like strcmp, returns 0 for identical. | |
240 | **/ | |
241 | int compare_addrinfo_sockaddr(const struct addrinfo *ai, | |
242 | const struct sockaddr_storage *ss) | |
243 | { | |
244 | int ss_family = get_sockaddr_family(ss); | |
245 | const char fn[] = "compare_addrinfo_sockaddr"; | |
c1e7217f | 246 | |
974f27e7 | 247 | if (ai->ai_family != ss_family) { |
fde045cd | 248 | rprintf(FLOG, "%s: response family %d != %d\n", |
974f27e7 MP |
249 | fn, ai->ai_family, ss_family); |
250 | return 1; | |
251 | } | |
252 | ||
39e01d2d MP |
253 | /* The comparison method depends on the particular AF. */ |
254 | if (ss_family == AF_INET) { | |
255 | const struct sockaddr_in *sin1, *sin2; | |
256 | ||
257 | sin1 = (const struct sockaddr_in *) ss; | |
258 | sin2 = (const struct sockaddr_in *) ai->ai_addr; | |
4cfa6156 | 259 | |
6780f720 MP |
260 | return memcmp(&sin1->sin_addr, &sin2->sin_addr, |
261 | sizeof sin1->sin_addr); | |
39e01d2d | 262 | } |
2b284ee3 | 263 | |
25ff0441 | 264 | #if INET6 |
2b284ee3 | 265 | if (ss_family == AF_INET6) { |
6780f720 MP |
266 | const struct sockaddr_in6 *sin1, *sin2; |
267 | ||
268 | sin1 = (const struct sockaddr_in6 *) ss; | |
269 | sin2 = (const struct sockaddr_in6 *) ai->ai_addr; | |
bc2b4963 | 270 | |
c1e7217f | 271 | if (ai->ai_addrlen < sizeof (struct sockaddr_in6)) { |
fde045cd | 272 | rprintf(FLOG, "%s: too short sockaddr_in6; length=%d\n", |
bc2b4963 DD |
273 | fn, ai->ai_addrlen); |
274 | return 1; | |
275 | } | |
276 | ||
277 | if (memcmp(&sin1->sin6_addr, &sin2->sin6_addr, | |
278 | sizeof sin1->sin6_addr)) | |
279 | return 1; | |
280 | ||
25ff0441 | 281 | #if HAVE_SOCKADDR_IN6_SCOPE_ID |
bc2b4963 DD |
282 | if (sin1->sin6_scope_id != sin2->sin6_scope_id) |
283 | return 1; | |
284 | #endif | |
285 | return 0; | |
39e01d2d MP |
286 | } |
287 | #endif /* INET6 */ | |
2b284ee3 WD |
288 | |
289 | /* don't know */ | |
290 | return 1; | |
974f27e7 MP |
291 | } |
292 | ||
293 | ||
af32f69e MP |
294 | /** |
295 | * Do a forward lookup on @p name_buf and make sure it corresponds to | |
296 | * @p ss -- otherwise we may be being spoofed. If we suspect we are, | |
297 | * then we don't abort the connection but just emit a warning, and | |
298 | * change @p name_buf to be "UNKNOWN". | |
6c92af20 MP |
299 | * |
300 | * We don't do anything with the service when checking the name, | |
301 | * because it doesn't seem that it could be spoofed in any way, and | |
302 | * getaddrinfo on random service names seems to cause problems on AIX. | |
af32f69e | 303 | **/ |
0cd2f407 MP |
304 | int check_name(int fd, |
305 | const struct sockaddr_storage *ss, | |
6c92af20 | 306 | char *name_buf) |
0cd2f407 MP |
307 | { |
308 | struct addrinfo hints, *res, *res0; | |
309 | int error; | |
310 | int ss_family = get_sockaddr_family(ss); | |
311 | ||
c1e7217f | 312 | memset(&hints, 0, sizeof hints); |
39e01d2d MP |
313 | hints.ai_family = ss_family; |
314 | hints.ai_flags = AI_CANONNAME; | |
0cd2f407 | 315 | hints.ai_socktype = SOCK_STREAM; |
6c92af20 | 316 | error = getaddrinfo(name_buf, NULL, &hints, &res0); |
0cd2f407 | 317 | if (error) { |
fde045cd | 318 | rprintf(FLOG, "forward name lookup for %s failed: %s\n", |
af32f69e | 319 | name_buf, gai_strerror(error)); |
0cd2f407 MP |
320 | strcpy(name_buf, default_name); |
321 | return error; | |
322 | } | |
323 | ||
324 | ||
974f27e7 MP |
325 | /* Given all these results, we expect that one of them will be |
326 | * the same as ss. The comparison is a bit complicated. */ | |
0cd2f407 | 327 | for (res = res0; res; res = res->ai_next) { |
974f27e7 MP |
328 | if (!compare_addrinfo_sockaddr(res, ss)) |
329 | break; /* OK, identical */ | |
0cd2f407 MP |
330 | } |
331 | ||
332 | if (!res0) { | |
333 | /* We hit the end of the list without finding an | |
334 | * address that was the same as ss. */ | |
fde045cd WD |
335 | rprintf(FLOG, "no known address for \"%s\": " |
336 | "spoofed address?\n", name_buf); | |
0cd2f407 | 337 | strcpy(name_buf, default_name); |
974f27e7 | 338 | } else if (res == NULL) { |
0cd2f407 MP |
339 | /* We hit the end of the list without finding an |
340 | * address that was the same as ss. */ | |
fde045cd WD |
341 | rprintf(FLOG, "%s is not a known address for \"%s\": " |
342 | "spoofed address?\n", client_addr(fd), name_buf); | |
0cd2f407 MP |
343 | strcpy(name_buf, default_name); |
344 | } | |
345 | ||
346 | freeaddrinfo(res0); | |
347 | return 0; | |
348 | } |