Commit | Line | Data |
---|---|---|
0f78b815 | 1 | /* |
0cd2f407 MP |
2 | * Functions for looking up the remote name or addr of a socket. |
3 | * | |
0f78b815 WD |
4 | * Copyright (C) 1992-2001 Andrew Tridgell <tridge@samba.org> |
5 | * Copyright (C) 2001, 2002 Martin Pool <mbp@samba.org> | |
ba2133d6 | 6 | * Copyright (C) 2002-2007 Wayne Davison |
0f78b815 WD |
7 | * |
8 | * This program is free software; you can redistribute it and/or modify | |
8e41b68e WD |
9 | * it under the terms of the GNU General Public License as published by |
10 | * the Free Software Foundation; either version 3 of the License, or | |
11 | * (at your option) any later version. | |
0f78b815 WD |
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 | * | |
e7c67065 | 18 | * You should have received a copy of the GNU General Public License along |
4fd842f9 | 19 | * with this program; if not, visit the http://fsf.org website. |
0f78b815 WD |
20 | */ |
21 | ||
22 | /* | |
0cd2f407 MP |
23 | * This file is now converted to use the new-style getaddrinfo() |
24 | * interface, which supports IPv6 but is also supported on recent | |
25 | * IPv4-only machines. On systems that don't have that interface, we | |
26 | * emulate it using the KAME implementation. | |
0f78b815 | 27 | */ |
0cd2f407 MP |
28 | |
29 | #include "rsync.h" | |
30 | ||
31 | static const char default_name[] = "UNKNOWN"; | |
542ad675 | 32 | extern int am_server; |
0cd2f407 MP |
33 | |
34 | ||
35 | /** | |
c1e7217f | 36 | * Return the IP addr of the client as a string |
0cd2f407 MP |
37 | **/ |
38 | char *client_addr(int fd) | |
39 | { | |
0cd2f407 MP |
40 | static char addr_buf[100]; |
41 | static int initialised; | |
b2ef4f61 WD |
42 | struct sockaddr_storage ss; |
43 | socklen_t length = sizeof ss; | |
44 | char *ssh_info, *p; | |
0cd2f407 | 45 | |
4cfa6156 WD |
46 | if (initialised) |
47 | return addr_buf; | |
0cd2f407 MP |
48 | |
49 | initialised = 1; | |
50 | ||
706c7530 | 51 | if (am_server) { /* daemon over --rsh mode */ |
55410368 | 52 | strlcpy(addr_buf, "0.0.0.0", sizeof addr_buf); |
b2ef4f61 WD |
53 | if ((ssh_info = getenv("SSH_CONNECTION")) != NULL |
54 | || (ssh_info = getenv("SSH_CLIENT")) != NULL | |
55 | || (ssh_info = getenv("SSH2_CLIENT")) != NULL) { | |
56 | strlcpy(addr_buf, ssh_info, sizeof addr_buf); | |
57 | /* Truncate the value to just the IP address. */ | |
58 | if ((p = strchr(addr_buf, ' ')) != NULL) | |
59 | *p = '\0'; | |
542ad675 | 60 | } |
3b5f6214 | 61 | } else { |
09021eab | 62 | client_sockaddr(fd, &ss, &length); |
3b5f6214 WD |
63 | getnameinfo((struct sockaddr *)&ss, length, |
64 | addr_buf, sizeof addr_buf, NULL, 0, NI_NUMERICHOST); | |
65 | } | |
09021eab | 66 | |
0cd2f407 MP |
67 | return addr_buf; |
68 | } | |
69 | ||
70 | ||
71 | static int get_sockaddr_family(const struct sockaddr_storage *ss) | |
72 | { | |
73 | return ((struct sockaddr *) ss)->sa_family; | |
74 | } | |
75 | ||
76 | ||
77 | /** | |
78 | * Return the DNS name of the client. | |
79 | * | |
80 | * The name is statically cached so that repeated lookups are quick, | |
81 | * so there is a limit of one lookup per customer. | |
82 | * | |
83 | * If anything goes wrong, including the name->addr->name check, then | |
84 | * we just use "UNKNOWN", so you can use that value in hosts allow | |
85 | * lines. | |
6c92af20 MP |
86 | * |
87 | * After translation from sockaddr to name we do a forward lookup to | |
88 | * make sure nobody is spoofing PTR records. | |
0cd2f407 MP |
89 | **/ |
90 | char *client_name(int fd) | |
91 | { | |
0cd2f407 MP |
92 | static char name_buf[100]; |
93 | static char port_buf[100]; | |
94 | static int initialised; | |
706c7530 | 95 | struct sockaddr_storage ss; |
1e736b8f | 96 | socklen_t ss_len; |
0cd2f407 | 97 | |
4cfa6156 WD |
98 | if (initialised) |
99 | return name_buf; | |
0cd2f407 | 100 | |
55410368 | 101 | strlcpy(name_buf, default_name, sizeof name_buf); |
0cd2f407 MP |
102 | initialised = 1; |
103 | ||
706c7530 WD |
104 | memset(&ss, 0, sizeof ss); |
105 | ||
2b284ee3 | 106 | if (am_server) { /* daemon over --rsh mode */ |
1e736b8f | 107 | char *addr = client_addr(fd); |
706c7530 WD |
108 | struct addrinfo hint, *answer; |
109 | int err; | |
1e736b8f | 110 | |
706c7530 WD |
111 | memset(&hint, 0, sizeof hint); |
112 | ||
6a6d2113 | 113 | #ifdef AI_NUMERICHOST |
706c7530 | 114 | hint.ai_flags = AI_NUMERICHOST; |
6a6d2113 | 115 | #endif |
706c7530 WD |
116 | hint.ai_socktype = SOCK_STREAM; |
117 | ||
118 | if ((err = getaddrinfo(addr, NULL, &hint, &answer)) != 0) { | |
fde045cd | 119 | rprintf(FLOG, "malformed address %s: %s\n", |
706c7530 WD |
120 | addr, gai_strerror(err)); |
121 | return name_buf; | |
1e736b8f | 122 | } |
706c7530 WD |
123 | |
124 | switch (answer->ai_family) { | |
125 | case AF_INET: | |
126 | ss_len = sizeof (struct sockaddr_in); | |
127 | memcpy(&ss, answer->ai_addr, ss_len); | |
128 | break; | |
4f5b0756 | 129 | #ifdef INET6 |
706c7530 WD |
130 | case AF_INET6: |
131 | ss_len = sizeof (struct sockaddr_in6); | |
132 | memcpy(&ss, answer->ai_addr, ss_len); | |
133 | break; | |
a6d8c3f3 | 134 | #endif |
55410368 WD |
135 | default: |
136 | exit_cleanup(RERR_SOCKETIO); | |
1e736b8f | 137 | } |
706c7530 | 138 | freeaddrinfo(answer); |
09021eab | 139 | } else { |
1e736b8f | 140 | ss_len = sizeof ss; |
09021eab | 141 | client_sockaddr(fd, &ss, &ss_len); |
09021eab | 142 | } |
0cd2f407 | 143 | |
fde045cd WD |
144 | if (lookup_name(fd, &ss, ss_len, name_buf, sizeof name_buf, |
145 | port_buf, sizeof port_buf) == 0) | |
55410368 | 146 | check_name(fd, &ss, name_buf, sizeof name_buf); |
1e736b8f | 147 | |
0cd2f407 MP |
148 | return name_buf; |
149 | } | |
150 | ||
151 | ||
152 | ||
153 | /** | |
af32f69e MP |
154 | * Get the sockaddr for the client. |
155 | * | |
156 | * If it comes in as an ipv4 address mapped into IPv6 format then we | |
157 | * convert it back to a regular IPv4. | |
0cd2f407 MP |
158 | **/ |
159 | void client_sockaddr(int fd, | |
160 | struct sockaddr_storage *ss, | |
161 | socklen_t *ss_len) | |
162 | { | |
c1e7217f | 163 | memset(ss, 0, sizeof *ss); |
bc2b4963 | 164 | |
0cd2f407 MP |
165 | if (getpeername(fd, (struct sockaddr *) ss, ss_len)) { |
166 | /* FIXME: Can we really not continue? */ | |
fde045cd | 167 | rsyserr(FLOG, errno, "getpeername on fd%d failed", fd); |
0cd2f407 MP |
168 | exit_cleanup(RERR_SOCKETIO); |
169 | } | |
170 | ||
4f5b0756 | 171 | #ifdef INET6 |
2b284ee3 | 172 | if (get_sockaddr_family(ss) == AF_INET6 && |
0cd2f407 MP |
173 | IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)ss)->sin6_addr)) { |
174 | /* OK, so ss is in the IPv6 family, but it is really | |
175 | * an IPv4 address: something like | |
176 | * "::ffff:10.130.1.2". If we use it as-is, then the | |
177 | * reverse lookup might fail or perhaps something else | |
178 | * bad might happen. So instead we convert it to an | |
179 | * equivalent address in the IPv4 address family. */ | |
180 | struct sockaddr_in6 sin6; | |
181 | struct sockaddr_in *sin; | |
182 | ||
c1e7217f | 183 | memcpy(&sin6, ss, sizeof sin6); |
0cd2f407 | 184 | sin = (struct sockaddr_in *)ss; |
c1e7217f | 185 | memset(sin, 0, sizeof *sin); |
0cd2f407 | 186 | sin->sin_family = AF_INET; |
c1e7217f | 187 | *ss_len = sizeof (struct sockaddr_in); |
4f5b0756 | 188 | #ifdef HAVE_SOCKADDR_IN_LEN |
0cd2f407 MP |
189 | sin->sin_len = *ss_len; |
190 | #endif | |
191 | sin->sin_port = sin6.sin6_port; | |
192 | ||
193 | /* There is a macro to extract the mapped part | |
194 | * (IN6_V4MAPPED_TO_SINADDR ?), but it does not seem | |
195 | * to be present in the Linux headers. */ | |
196 | memcpy(&sin->sin_addr, &sin6.sin6_addr.s6_addr[12], | |
c1e7217f | 197 | sizeof sin->sin_addr); |
2b284ee3 | 198 | } |
0cd2f407 MP |
199 | #endif |
200 | } | |
201 | ||
202 | ||
203 | /** | |
204 | * Look up a name from @p ss into @p name_buf. | |
6c92af20 MP |
205 | * |
206 | * @param fd file descriptor for client socket. | |
0cd2f407 MP |
207 | **/ |
208 | int lookup_name(int fd, const struct sockaddr_storage *ss, | |
209 | socklen_t ss_len, | |
55410368 WD |
210 | char *name_buf, size_t name_buf_size, |
211 | char *port_buf, size_t port_buf_size) | |
0cd2f407 MP |
212 | { |
213 | int name_err; | |
4cfa6156 | 214 | |
0cd2f407 MP |
215 | /* reverse lookup */ |
216 | name_err = getnameinfo((struct sockaddr *) ss, ss_len, | |
55410368 WD |
217 | name_buf, name_buf_size, |
218 | port_buf, port_buf_size, | |
0cd2f407 MP |
219 | NI_NAMEREQD | NI_NUMERICSERV); |
220 | if (name_err != 0) { | |
55410368 | 221 | strlcpy(name_buf, default_name, name_buf_size); |
fde045cd WD |
222 | rprintf(FLOG, "name lookup failed for %s: %s\n", |
223 | client_addr(fd), gai_strerror(name_err)); | |
0cd2f407 MP |
224 | return name_err; |
225 | } | |
226 | ||
227 | return 0; | |
228 | } | |
229 | ||
230 | ||
231 | ||
974f27e7 MP |
232 | /** |
233 | * Compare an addrinfo from the resolver to a sockinfo. | |
234 | * | |
235 | * Like strcmp, returns 0 for identical. | |
236 | **/ | |
237 | int compare_addrinfo_sockaddr(const struct addrinfo *ai, | |
238 | const struct sockaddr_storage *ss) | |
239 | { | |
240 | int ss_family = get_sockaddr_family(ss); | |
241 | const char fn[] = "compare_addrinfo_sockaddr"; | |
c1e7217f | 242 | |
974f27e7 | 243 | if (ai->ai_family != ss_family) { |
fde045cd | 244 | rprintf(FLOG, "%s: response family %d != %d\n", |
974f27e7 MP |
245 | fn, ai->ai_family, ss_family); |
246 | return 1; | |
247 | } | |
248 | ||
39e01d2d MP |
249 | /* The comparison method depends on the particular AF. */ |
250 | if (ss_family == AF_INET) { | |
251 | const struct sockaddr_in *sin1, *sin2; | |
252 | ||
253 | sin1 = (const struct sockaddr_in *) ss; | |
254 | sin2 = (const struct sockaddr_in *) ai->ai_addr; | |
4cfa6156 | 255 | |
6780f720 MP |
256 | return memcmp(&sin1->sin_addr, &sin2->sin_addr, |
257 | sizeof sin1->sin_addr); | |
39e01d2d | 258 | } |
2b284ee3 | 259 | |
4f5b0756 | 260 | #ifdef INET6 |
2b284ee3 | 261 | if (ss_family == AF_INET6) { |
6780f720 MP |
262 | const struct sockaddr_in6 *sin1, *sin2; |
263 | ||
264 | sin1 = (const struct sockaddr_in6 *) ss; | |
265 | sin2 = (const struct sockaddr_in6 *) ai->ai_addr; | |
bc2b4963 | 266 | |
c1e7217f | 267 | if (ai->ai_addrlen < sizeof (struct sockaddr_in6)) { |
fde045cd | 268 | rprintf(FLOG, "%s: too short sockaddr_in6; length=%d\n", |
bc2b4963 DD |
269 | fn, ai->ai_addrlen); |
270 | return 1; | |
271 | } | |
272 | ||
273 | if (memcmp(&sin1->sin6_addr, &sin2->sin6_addr, | |
274 | sizeof sin1->sin6_addr)) | |
275 | return 1; | |
276 | ||
4f5b0756 | 277 | #ifdef HAVE_SOCKADDR_IN6_SCOPE_ID |
bc2b4963 DD |
278 | if (sin1->sin6_scope_id != sin2->sin6_scope_id) |
279 | return 1; | |
280 | #endif | |
281 | return 0; | |
39e01d2d MP |
282 | } |
283 | #endif /* INET6 */ | |
2b284ee3 WD |
284 | |
285 | /* don't know */ | |
286 | return 1; | |
974f27e7 MP |
287 | } |
288 | ||
289 | ||
af32f69e MP |
290 | /** |
291 | * Do a forward lookup on @p name_buf and make sure it corresponds to | |
292 | * @p ss -- otherwise we may be being spoofed. If we suspect we are, | |
293 | * then we don't abort the connection but just emit a warning, and | |
294 | * change @p name_buf to be "UNKNOWN". | |
6c92af20 MP |
295 | * |
296 | * We don't do anything with the service when checking the name, | |
297 | * because it doesn't seem that it could be spoofed in any way, and | |
298 | * getaddrinfo on random service names seems to cause problems on AIX. | |
af32f69e | 299 | **/ |
0cd2f407 MP |
300 | int check_name(int fd, |
301 | const struct sockaddr_storage *ss, | |
55410368 | 302 | char *name_buf, size_t name_buf_size) |
0cd2f407 MP |
303 | { |
304 | struct addrinfo hints, *res, *res0; | |
305 | int error; | |
306 | int ss_family = get_sockaddr_family(ss); | |
307 | ||
c1e7217f | 308 | memset(&hints, 0, sizeof hints); |
39e01d2d MP |
309 | hints.ai_family = ss_family; |
310 | hints.ai_flags = AI_CANONNAME; | |
0cd2f407 | 311 | hints.ai_socktype = SOCK_STREAM; |
6c92af20 | 312 | error = getaddrinfo(name_buf, NULL, &hints, &res0); |
0cd2f407 | 313 | if (error) { |
fde045cd | 314 | rprintf(FLOG, "forward name lookup for %s failed: %s\n", |
af32f69e | 315 | name_buf, gai_strerror(error)); |
55410368 | 316 | strlcpy(name_buf, default_name, name_buf_size); |
0cd2f407 MP |
317 | return error; |
318 | } | |
319 | ||
974f27e7 MP |
320 | /* Given all these results, we expect that one of them will be |
321 | * the same as ss. The comparison is a bit complicated. */ | |
0cd2f407 | 322 | for (res = res0; res; res = res->ai_next) { |
974f27e7 MP |
323 | if (!compare_addrinfo_sockaddr(res, ss)) |
324 | break; /* OK, identical */ | |
0cd2f407 MP |
325 | } |
326 | ||
327 | if (!res0) { | |
328 | /* We hit the end of the list without finding an | |
329 | * address that was the same as ss. */ | |
fde045cd WD |
330 | rprintf(FLOG, "no known address for \"%s\": " |
331 | "spoofed address?\n", name_buf); | |
55410368 | 332 | strlcpy(name_buf, default_name, name_buf_size); |
974f27e7 | 333 | } else if (res == NULL) { |
0cd2f407 MP |
334 | /* We hit the end of the list without finding an |
335 | * address that was the same as ss. */ | |
fde045cd WD |
336 | rprintf(FLOG, "%s is not a known address for \"%s\": " |
337 | "spoofed address?\n", client_addr(fd), name_buf); | |
55410368 | 338 | strlcpy(name_buf, default_name, name_buf_size); |
0cd2f407 MP |
339 | } |
340 | ||
341 | freeaddrinfo(res0); | |
342 | return 0; | |
343 | } |