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> | |
6 | * Copyright (C) 2002, 2003, 2004 Wayne Davison | |
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 | * | |
e7c67065 WD |
18 | * You should have received a copy of the GNU General Public License along |
19 | * with this program; if not, write to the Free Software Foundation, Inc., | |
20 | * 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA. | |
0f78b815 WD |
21 | */ |
22 | ||
23 | /* | |
0cd2f407 MP |
24 | * This file is now converted to use the new-style getaddrinfo() |
25 | * interface, which supports IPv6 but is also supported on recent | |
26 | * IPv4-only machines. On systems that don't have that interface, we | |
27 | * emulate it using the KAME implementation. | |
0f78b815 | 28 | */ |
0cd2f407 MP |
29 | |
30 | #include "rsync.h" | |
31 | ||
32 | static const char default_name[] = "UNKNOWN"; | |
542ad675 | 33 | extern int am_server; |
0cd2f407 MP |
34 | |
35 | ||
36 | /** | |
c1e7217f | 37 | * Return the IP addr of the client as a string |
0cd2f407 MP |
38 | **/ |
39 | char *client_addr(int fd) | |
40 | { | |
0cd2f407 MP |
41 | static char addr_buf[100]; |
42 | static int initialised; | |
b2ef4f61 WD |
43 | struct sockaddr_storage ss; |
44 | socklen_t length = sizeof ss; | |
45 | char *ssh_info, *p; | |
0cd2f407 | 46 | |
4cfa6156 WD |
47 | if (initialised) |
48 | return addr_buf; | |
0cd2f407 MP |
49 | |
50 | initialised = 1; | |
51 | ||
706c7530 | 52 | if (am_server) { /* daemon over --rsh mode */ |
55410368 | 53 | strlcpy(addr_buf, "0.0.0.0", sizeof addr_buf); |
b2ef4f61 WD |
54 | if ((ssh_info = getenv("SSH_CONNECTION")) != NULL |
55 | || (ssh_info = getenv("SSH_CLIENT")) != NULL | |
56 | || (ssh_info = getenv("SSH2_CLIENT")) != NULL) { | |
57 | strlcpy(addr_buf, ssh_info, sizeof addr_buf); | |
58 | /* Truncate the value to just the IP address. */ | |
59 | if ((p = strchr(addr_buf, ' ')) != NULL) | |
60 | *p = '\0'; | |
542ad675 | 61 | } |
3b5f6214 | 62 | } else { |
09021eab | 63 | client_sockaddr(fd, &ss, &length); |
3b5f6214 WD |
64 | getnameinfo((struct sockaddr *)&ss, length, |
65 | addr_buf, sizeof addr_buf, NULL, 0, NI_NUMERICHOST); | |
66 | } | |
09021eab | 67 | |
0cd2f407 MP |
68 | return addr_buf; |
69 | } | |
70 | ||
71 | ||
72 | static int get_sockaddr_family(const struct sockaddr_storage *ss) | |
73 | { | |
74 | return ((struct sockaddr *) ss)->sa_family; | |
75 | } | |
76 | ||
77 | ||
78 | /** | |
79 | * Return the DNS name of the client. | |
80 | * | |
81 | * The name is statically cached so that repeated lookups are quick, | |
82 | * so there is a limit of one lookup per customer. | |
83 | * | |
84 | * If anything goes wrong, including the name->addr->name check, then | |
85 | * we just use "UNKNOWN", so you can use that value in hosts allow | |
86 | * lines. | |
6c92af20 MP |
87 | * |
88 | * After translation from sockaddr to name we do a forward lookup to | |
89 | * make sure nobody is spoofing PTR records. | |
0cd2f407 MP |
90 | **/ |
91 | char *client_name(int fd) | |
92 | { | |
0cd2f407 MP |
93 | static char name_buf[100]; |
94 | static char port_buf[100]; | |
95 | static int initialised; | |
706c7530 | 96 | struct sockaddr_storage ss; |
1e736b8f | 97 | socklen_t ss_len; |
0cd2f407 | 98 | |
4cfa6156 WD |
99 | if (initialised) |
100 | return name_buf; | |
0cd2f407 | 101 | |
55410368 | 102 | strlcpy(name_buf, default_name, sizeof name_buf); |
0cd2f407 MP |
103 | initialised = 1; |
104 | ||
706c7530 WD |
105 | memset(&ss, 0, sizeof ss); |
106 | ||
2b284ee3 | 107 | if (am_server) { /* daemon over --rsh mode */ |
1e736b8f | 108 | char *addr = client_addr(fd); |
706c7530 WD |
109 | struct addrinfo hint, *answer; |
110 | int err; | |
1e736b8f | 111 | |
706c7530 WD |
112 | memset(&hint, 0, sizeof hint); |
113 | ||
6a6d2113 | 114 | #ifdef AI_NUMERICHOST |
706c7530 | 115 | hint.ai_flags = AI_NUMERICHOST; |
6a6d2113 | 116 | #endif |
706c7530 WD |
117 | hint.ai_socktype = SOCK_STREAM; |
118 | ||
119 | if ((err = getaddrinfo(addr, NULL, &hint, &answer)) != 0) { | |
fde045cd | 120 | rprintf(FLOG, "malformed address %s: %s\n", |
706c7530 WD |
121 | addr, gai_strerror(err)); |
122 | return name_buf; | |
1e736b8f | 123 | } |
706c7530 WD |
124 | |
125 | switch (answer->ai_family) { | |
126 | case AF_INET: | |
127 | ss_len = sizeof (struct sockaddr_in); | |
128 | memcpy(&ss, answer->ai_addr, ss_len); | |
129 | break; | |
4f5b0756 | 130 | #ifdef INET6 |
706c7530 WD |
131 | case AF_INET6: |
132 | ss_len = sizeof (struct sockaddr_in6); | |
133 | memcpy(&ss, answer->ai_addr, ss_len); | |
134 | break; | |
a6d8c3f3 | 135 | #endif |
55410368 WD |
136 | default: |
137 | exit_cleanup(RERR_SOCKETIO); | |
1e736b8f | 138 | } |
706c7530 | 139 | freeaddrinfo(answer); |
09021eab | 140 | } else { |
1e736b8f | 141 | ss_len = sizeof ss; |
09021eab | 142 | client_sockaddr(fd, &ss, &ss_len); |
09021eab | 143 | } |
0cd2f407 | 144 | |
fde045cd WD |
145 | if (lookup_name(fd, &ss, ss_len, name_buf, sizeof name_buf, |
146 | port_buf, sizeof port_buf) == 0) | |
55410368 | 147 | check_name(fd, &ss, name_buf, sizeof name_buf); |
1e736b8f | 148 | |
0cd2f407 MP |
149 | return name_buf; |
150 | } | |
151 | ||
152 | ||
153 | ||
154 | /** | |
af32f69e MP |
155 | * Get the sockaddr for the client. |
156 | * | |
157 | * If it comes in as an ipv4 address mapped into IPv6 format then we | |
158 | * convert it back to a regular IPv4. | |
0cd2f407 MP |
159 | **/ |
160 | void client_sockaddr(int fd, | |
161 | struct sockaddr_storage *ss, | |
162 | socklen_t *ss_len) | |
163 | { | |
c1e7217f | 164 | memset(ss, 0, sizeof *ss); |
bc2b4963 | 165 | |
0cd2f407 MP |
166 | if (getpeername(fd, (struct sockaddr *) ss, ss_len)) { |
167 | /* FIXME: Can we really not continue? */ | |
fde045cd | 168 | rsyserr(FLOG, errno, "getpeername on fd%d failed", fd); |
0cd2f407 MP |
169 | exit_cleanup(RERR_SOCKETIO); |
170 | } | |
171 | ||
4f5b0756 | 172 | #ifdef INET6 |
2b284ee3 | 173 | if (get_sockaddr_family(ss) == AF_INET6 && |
0cd2f407 MP |
174 | IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)ss)->sin6_addr)) { |
175 | /* OK, so ss is in the IPv6 family, but it is really | |
176 | * an IPv4 address: something like | |
177 | * "::ffff:10.130.1.2". If we use it as-is, then the | |
178 | * reverse lookup might fail or perhaps something else | |
179 | * bad might happen. So instead we convert it to an | |
180 | * equivalent address in the IPv4 address family. */ | |
181 | struct sockaddr_in6 sin6; | |
182 | struct sockaddr_in *sin; | |
183 | ||
c1e7217f | 184 | memcpy(&sin6, ss, sizeof sin6); |
0cd2f407 | 185 | sin = (struct sockaddr_in *)ss; |
c1e7217f | 186 | memset(sin, 0, sizeof *sin); |
0cd2f407 | 187 | sin->sin_family = AF_INET; |
c1e7217f | 188 | *ss_len = sizeof (struct sockaddr_in); |
4f5b0756 | 189 | #ifdef HAVE_SOCKADDR_IN_LEN |
0cd2f407 MP |
190 | sin->sin_len = *ss_len; |
191 | #endif | |
192 | sin->sin_port = sin6.sin6_port; | |
193 | ||
194 | /* There is a macro to extract the mapped part | |
195 | * (IN6_V4MAPPED_TO_SINADDR ?), but it does not seem | |
196 | * to be present in the Linux headers. */ | |
197 | memcpy(&sin->sin_addr, &sin6.sin6_addr.s6_addr[12], | |
c1e7217f | 198 | sizeof sin->sin_addr); |
2b284ee3 | 199 | } |
0cd2f407 MP |
200 | #endif |
201 | } | |
202 | ||
203 | ||
204 | /** | |
205 | * Look up a name from @p ss into @p name_buf. | |
6c92af20 MP |
206 | * |
207 | * @param fd file descriptor for client socket. | |
0cd2f407 MP |
208 | **/ |
209 | int lookup_name(int fd, const struct sockaddr_storage *ss, | |
210 | socklen_t ss_len, | |
55410368 WD |
211 | char *name_buf, size_t name_buf_size, |
212 | char *port_buf, size_t port_buf_size) | |
0cd2f407 MP |
213 | { |
214 | int name_err; | |
4cfa6156 | 215 | |
0cd2f407 MP |
216 | /* reverse lookup */ |
217 | name_err = getnameinfo((struct sockaddr *) ss, ss_len, | |
55410368 WD |
218 | name_buf, name_buf_size, |
219 | port_buf, port_buf_size, | |
0cd2f407 MP |
220 | NI_NAMEREQD | NI_NUMERICSERV); |
221 | if (name_err != 0) { | |
55410368 | 222 | strlcpy(name_buf, default_name, name_buf_size); |
fde045cd WD |
223 | rprintf(FLOG, "name lookup failed for %s: %s\n", |
224 | client_addr(fd), gai_strerror(name_err)); | |
0cd2f407 MP |
225 | return name_err; |
226 | } | |
227 | ||
228 | return 0; | |
229 | } | |
230 | ||
231 | ||
232 | ||
974f27e7 MP |
233 | /** |
234 | * Compare an addrinfo from the resolver to a sockinfo. | |
235 | * | |
236 | * Like strcmp, returns 0 for identical. | |
237 | **/ | |
238 | int compare_addrinfo_sockaddr(const struct addrinfo *ai, | |
239 | const struct sockaddr_storage *ss) | |
240 | { | |
241 | int ss_family = get_sockaddr_family(ss); | |
242 | const char fn[] = "compare_addrinfo_sockaddr"; | |
c1e7217f | 243 | |
974f27e7 | 244 | if (ai->ai_family != ss_family) { |
fde045cd | 245 | rprintf(FLOG, "%s: response family %d != %d\n", |
974f27e7 MP |
246 | fn, ai->ai_family, ss_family); |
247 | return 1; | |
248 | } | |
249 | ||
39e01d2d MP |
250 | /* The comparison method depends on the particular AF. */ |
251 | if (ss_family == AF_INET) { | |
252 | const struct sockaddr_in *sin1, *sin2; | |
253 | ||
254 | sin1 = (const struct sockaddr_in *) ss; | |
255 | sin2 = (const struct sockaddr_in *) ai->ai_addr; | |
4cfa6156 | 256 | |
6780f720 MP |
257 | return memcmp(&sin1->sin_addr, &sin2->sin_addr, |
258 | sizeof sin1->sin_addr); | |
39e01d2d | 259 | } |
2b284ee3 | 260 | |
4f5b0756 | 261 | #ifdef INET6 |
2b284ee3 | 262 | if (ss_family == AF_INET6) { |
6780f720 MP |
263 | const struct sockaddr_in6 *sin1, *sin2; |
264 | ||
265 | sin1 = (const struct sockaddr_in6 *) ss; | |
266 | sin2 = (const struct sockaddr_in6 *) ai->ai_addr; | |
bc2b4963 | 267 | |
c1e7217f | 268 | if (ai->ai_addrlen < sizeof (struct sockaddr_in6)) { |
fde045cd | 269 | rprintf(FLOG, "%s: too short sockaddr_in6; length=%d\n", |
bc2b4963 DD |
270 | fn, ai->ai_addrlen); |
271 | return 1; | |
272 | } | |
273 | ||
274 | if (memcmp(&sin1->sin6_addr, &sin2->sin6_addr, | |
275 | sizeof sin1->sin6_addr)) | |
276 | return 1; | |
277 | ||
4f5b0756 | 278 | #ifdef HAVE_SOCKADDR_IN6_SCOPE_ID |
bc2b4963 DD |
279 | if (sin1->sin6_scope_id != sin2->sin6_scope_id) |
280 | return 1; | |
281 | #endif | |
282 | return 0; | |
39e01d2d MP |
283 | } |
284 | #endif /* INET6 */ | |
2b284ee3 WD |
285 | |
286 | /* don't know */ | |
287 | return 1; | |
974f27e7 MP |
288 | } |
289 | ||
290 | ||
af32f69e MP |
291 | /** |
292 | * Do a forward lookup on @p name_buf and make sure it corresponds to | |
293 | * @p ss -- otherwise we may be being spoofed. If we suspect we are, | |
294 | * then we don't abort the connection but just emit a warning, and | |
295 | * change @p name_buf to be "UNKNOWN". | |
6c92af20 MP |
296 | * |
297 | * We don't do anything with the service when checking the name, | |
298 | * because it doesn't seem that it could be spoofed in any way, and | |
299 | * getaddrinfo on random service names seems to cause problems on AIX. | |
af32f69e | 300 | **/ |
0cd2f407 MP |
301 | int check_name(int fd, |
302 | const struct sockaddr_storage *ss, | |
55410368 | 303 | char *name_buf, size_t name_buf_size) |
0cd2f407 MP |
304 | { |
305 | struct addrinfo hints, *res, *res0; | |
306 | int error; | |
307 | int ss_family = get_sockaddr_family(ss); | |
308 | ||
c1e7217f | 309 | memset(&hints, 0, sizeof hints); |
39e01d2d MP |
310 | hints.ai_family = ss_family; |
311 | hints.ai_flags = AI_CANONNAME; | |
0cd2f407 | 312 | hints.ai_socktype = SOCK_STREAM; |
6c92af20 | 313 | error = getaddrinfo(name_buf, NULL, &hints, &res0); |
0cd2f407 | 314 | if (error) { |
fde045cd | 315 | rprintf(FLOG, "forward name lookup for %s failed: %s\n", |
af32f69e | 316 | name_buf, gai_strerror(error)); |
55410368 | 317 | strlcpy(name_buf, default_name, name_buf_size); |
0cd2f407 MP |
318 | return error; |
319 | } | |
320 | ||
974f27e7 MP |
321 | /* Given all these results, we expect that one of them will be |
322 | * the same as ss. The comparison is a bit complicated. */ | |
0cd2f407 | 323 | for (res = res0; res; res = res->ai_next) { |
974f27e7 MP |
324 | if (!compare_addrinfo_sockaddr(res, ss)) |
325 | break; /* OK, identical */ | |
0cd2f407 MP |
326 | } |
327 | ||
328 | if (!res0) { | |
329 | /* We hit the end of the list without finding an | |
330 | * address that was the same as ss. */ | |
fde045cd WD |
331 | rprintf(FLOG, "no known address for \"%s\": " |
332 | "spoofed address?\n", name_buf); | |
55410368 | 333 | strlcpy(name_buf, default_name, name_buf_size); |
974f27e7 | 334 | } else if (res == NULL) { |
0cd2f407 MP |
335 | /* We hit the end of the list without finding an |
336 | * address that was the same as ss. */ | |
fde045cd WD |
337 | rprintf(FLOG, "%s is not a known address for \"%s\": " |
338 | "spoofed address?\n", client_addr(fd), name_buf); | |
55410368 | 339 | strlcpy(name_buf, default_name, name_buf_size); |
0cd2f407 MP |
340 | } |
341 | ||
342 | freeaddrinfo(res0); | |
343 | return 0; | |
344 | } |