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Commit | Line | Data |
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db9ecf05 | 1 | /* SPDX-License-Identifier: LGPL-2.1-or-later */ |
dd0bc0f1 | 2 | |
ca78ad1d ZJS |
3 | #include <sys/stat.h> |
4 | #include <sys/types.h> | |
5 | #include <unistd.h> | |
6 | ||
dd0bc0f1 LP |
7 | #include "fd-util.h" |
8 | #include "fileio.h" | |
9 | #include "hostname-util.h" | |
dd0bc0f1 | 10 | #include "resolved-dns-synthesize.h" |
7c777a77 | 11 | #include "resolved-etc-hosts.h" |
5c3fa98d | 12 | #include "socket-netlink.h" |
36d892b7 | 13 | #include "stat-util.h" |
dd0bc0f1 LP |
14 | #include "string-util.h" |
15 | #include "strv.h" | |
16 | #include "time-util.h" | |
17 | ||
18 | /* Recheck /etc/hosts at most once every 2s */ | |
19 | #define ETC_HOSTS_RECHECK_USEC (2*USEC_PER_SEC) | |
20 | ||
133eedad | 21 | static void etc_hosts_item_by_address_free(EtcHostsItemByAddress *item) { |
37b7cc8d ZJS |
22 | strv_free(item->names); |
23 | free(item); | |
24 | } | |
dd0bc0f1 | 25 | |
a1e92eee | 26 | static void etc_hosts_item_by_name_free(EtcHostsItemByName *item) { |
37b7cc8d ZJS |
27 | free(item->name); |
28 | free(item->addresses); | |
29 | free(item); | |
30 | } | |
dd0bc0f1 | 31 | |
0f7bdf35 YW |
32 | void etc_hosts_clear(EtcHosts *hosts) { |
33 | assert(hosts); | |
34 | ||
133eedad | 35 | hosts->by_address = hashmap_free_with_destructor(hosts->by_address, etc_hosts_item_by_address_free); |
37b7cc8d | 36 | hosts->by_name = hashmap_free_with_destructor(hosts->by_name, etc_hosts_item_by_name_free); |
fd373593 | 37 | hosts->no_address = set_free_free(hosts->no_address); |
37b7cc8d | 38 | } |
dd0bc0f1 | 39 | |
37b7cc8d | 40 | void manager_etc_hosts_flush(Manager *m) { |
0f7bdf35 | 41 | etc_hosts_clear(&m->etc_hosts); |
36d892b7 | 42 | m->etc_hosts_stat = (struct stat) {}; |
dd0bc0f1 LP |
43 | } |
44 | ||
37b7cc8d | 45 | static int parse_line(EtcHosts *hosts, unsigned nr, const char *line) { |
0351eb11 YW |
46 | _cleanup_free_ char *address_str = NULL; |
47 | struct in_addr_data address = {}; | |
fd373593 | 48 | bool found = false; |
133eedad | 49 | EtcHostsItemByAddress *item; |
dd0bc0f1 LP |
50 | int r; |
51 | ||
37b7cc8d | 52 | assert(hosts); |
0351eb11 | 53 | assert(line); |
dd0bc0f1 | 54 | |
0351eb11 YW |
55 | r = extract_first_word(&line, &address_str, NULL, EXTRACT_RELAX); |
56 | if (r < 0) | |
bd005277 ZJS |
57 | return log_error_errno(r, "/etc/hosts:%u: failed to extract address: %m", nr); |
58 | assert(r > 0); /* We already checked that the line is not empty, so it should contain *something* */ | |
0351eb11 | 59 | |
7bf8c3de | 60 | r = in_addr_ifindex_from_string_auto(address_str, &address.family, &address.address, NULL); |
bd005277 ZJS |
61 | if (r < 0) { |
62 | log_warning_errno(r, "/etc/hosts:%u: address '%s' is invalid, ignoring: %m", nr, address_str); | |
63 | return 0; | |
64 | } | |
0351eb11 | 65 | |
94876904 | 66 | r = in_addr_data_is_null(&address); |
bd005277 ZJS |
67 | if (r < 0) { |
68 | log_warning_errno(r, "/etc/hosts:%u: address '%s' is invalid, ignoring: %m", nr, address_str); | |
69 | return 0; | |
70 | } | |
dd0bc0f1 LP |
71 | if (r > 0) |
72 | /* This is an 0.0.0.0 or :: item, which we assume means that we shall map the specified hostname to | |
73 | * nothing. */ | |
74 | item = NULL; | |
75 | else { | |
78fc21a1 | 76 | /* If this is a normal address, then simply add entry mapping it to the specified names */ |
dd0bc0f1 | 77 | |
37b7cc8d | 78 | item = hashmap_get(hosts->by_address, &address); |
0351eb11 | 79 | if (!item) { |
37b7cc8d | 80 | r = hashmap_ensure_allocated(&hosts->by_address, &in_addr_data_hash_ops); |
dd0bc0f1 LP |
81 | if (r < 0) |
82 | return log_oom(); | |
83 | ||
133eedad | 84 | item = new(EtcHostsItemByAddress, 1); |
dd0bc0f1 LP |
85 | if (!item) |
86 | return log_oom(); | |
87 | ||
133eedad | 88 | *item = (EtcHostsItemByAddress) { |
1ed31408 LP |
89 | .address = address, |
90 | }; | |
dd0bc0f1 | 91 | |
37b7cc8d | 92 | r = hashmap_put(hosts->by_address, &item->address, item); |
dd0bc0f1 LP |
93 | if (r < 0) { |
94 | free(item); | |
95 | return log_oom(); | |
96 | } | |
97 | } | |
98 | } | |
99 | ||
0351eb11 YW |
100 | for (;;) { |
101 | _cleanup_free_ char *name = NULL; | |
dd0bc0f1 LP |
102 | EtcHostsItemByName *bn; |
103 | ||
0351eb11 YW |
104 | r = extract_first_word(&line, &name, NULL, EXTRACT_RELAX); |
105 | if (r < 0) | |
38b38500 | 106 | return log_error_errno(r, "/etc/hosts:%u: couldn't extract hostname: %m", nr); |
0351eb11 YW |
107 | if (r == 0) |
108 | break; | |
109 | ||
fd373593 ZJS |
110 | found = true; |
111 | ||
7470cc4c | 112 | r = dns_name_is_valid_ldh(name); |
bd005277 | 113 | if (r <= 0) { |
98b1eb71 YW |
114 | if (r < 0) |
115 | log_warning_errno(r, "/etc/hosts:%u: Failed to check the validity of hostname \"%s\", ignoring: %m", nr, name); | |
116 | else | |
117 | log_warning("/etc/hosts:%u: hostname \"%s\" is not valid, ignoring.", nr, name); | |
bd005277 ZJS |
118 | continue; |
119 | } | |
120 | ||
fd373593 ZJS |
121 | if (!item) { |
122 | /* Optimize the case where we don't need to store any addresses, by storing | |
123 | * only the name in a dedicated Set instead of the hashmap */ | |
124 | ||
ab9dd0b9 | 125 | r = set_ensure_consume(&hosts->no_address, &dns_name_hash_ops, TAKE_PTR(name)); |
fd373593 ZJS |
126 | if (r < 0) |
127 | return r; | |
128 | ||
fd373593 | 129 | continue; |
0351eb11 YW |
130 | } |
131 | ||
eb164c51 | 132 | r = strv_extend_with_size(&item->names, &item->n_names, name); |
fd373593 ZJS |
133 | if (r < 0) |
134 | return log_oom(); | |
135 | ||
37b7cc8d | 136 | bn = hashmap_get(hosts->by_name, name); |
dd0bc0f1 | 137 | if (!bn) { |
37b7cc8d | 138 | r = hashmap_ensure_allocated(&hosts->by_name, &dns_name_hash_ops); |
dd0bc0f1 LP |
139 | if (r < 0) |
140 | return log_oom(); | |
141 | ||
142 | bn = new0(EtcHostsItemByName, 1); | |
143 | if (!bn) | |
144 | return log_oom(); | |
145 | ||
37b7cc8d | 146 | r = hashmap_put(hosts->by_name, name, bn); |
dd0bc0f1 | 147 | if (r < 0) { |
dd0bc0f1 LP |
148 | free(bn); |
149 | return log_oom(); | |
150 | } | |
0351eb11 YW |
151 | |
152 | bn->name = TAKE_PTR(name); | |
dd0bc0f1 LP |
153 | } |
154 | ||
319a4f4b | 155 | if (!GREEDY_REALLOC(bn->addresses, bn->n_addresses + 1)) |
fd373593 | 156 | return log_oom(); |
dd0bc0f1 | 157 | |
fd373593 | 158 | bn->addresses[bn->n_addresses++] = &item->address; |
dd0bc0f1 LP |
159 | } |
160 | ||
baaa35ad | 161 | if (!found) |
38b38500 | 162 | log_warning("/etc/hosts:%u: line is missing any hostnames", nr); |
dd0bc0f1 | 163 | |
0351eb11 | 164 | return 0; |
dd0bc0f1 LP |
165 | } |
166 | ||
9ca875e8 LP |
167 | static void strip_localhost(EtcHosts *hosts) { |
168 | static const struct in_addr_data local_in_addrs[] = { | |
169 | { | |
170 | .family = AF_INET, | |
171 | #if __BYTE_ORDER == __LITTLE_ENDIAN | |
172 | /* We want constant expressions here, that's why we don't use htole32() here */ | |
173 | .address.in.s_addr = UINT32_C(0x0100007F), | |
174 | #else | |
175 | .address.in.s_addr = UINT32_C(0x7F000001), | |
176 | #endif | |
177 | }, | |
178 | { | |
179 | .family = AF_INET6, | |
180 | .address.in6 = IN6ADDR_LOOPBACK_INIT, | |
181 | }, | |
182 | }; | |
183 | ||
133eedad | 184 | EtcHostsItemByAddress *item; |
9ca875e8 LP |
185 | |
186 | assert(hosts); | |
187 | ||
188 | /* Removes the 'localhost' entry from what we loaded. But only if the mapping is exclusively between | |
189 | * 127.0.0.1 and localhost (or aliases to that we recognize). If there's any other name assigned to | |
190 | * it, we leave the entry in. | |
191 | * | |
192 | * This way our regular synthesizing can take over, but only if it would result in the exact same | |
193 | * mappings. */ | |
194 | ||
195 | for (size_t j = 0; j < ELEMENTSOF(local_in_addrs); j++) { | |
196 | bool all_localhost, in_order; | |
9ca875e8 LP |
197 | |
198 | item = hashmap_get(hosts->by_address, local_in_addrs + j); | |
199 | if (!item) | |
200 | continue; | |
201 | ||
202 | /* Check whether all hostnames the loopback address points to are localhost ones */ | |
203 | all_localhost = true; | |
204 | STRV_FOREACH(i, item->names) | |
205 | if (!is_localhost(*i)) { | |
206 | all_localhost = false; | |
207 | break; | |
208 | } | |
209 | ||
210 | if (!all_localhost) /* Not all names are localhost, hence keep the entries for this address. */ | |
211 | continue; | |
212 | ||
213 | /* Now check if the names listed for this address actually all point back just to this | |
214 | * address (or the other loopback address). If not, let's stay away from this too. */ | |
215 | in_order = true; | |
216 | STRV_FOREACH(i, item->names) { | |
217 | EtcHostsItemByName *n; | |
218 | bool all_local_address; | |
219 | ||
220 | n = hashmap_get(hosts->by_name, *i); | |
221 | if (!n) /* No reverse entry? Then almost certainly the entry already got deleted from | |
222 | * the previous iteration of this loop, i.e. via the other protocol */ | |
223 | break; | |
224 | ||
225 | /* Now check if the addresses of this item are all localhost addresses */ | |
226 | all_local_address = true; | |
227 | for (size_t m = 0; m < n->n_addresses; m++) | |
228 | if (!in_addr_is_localhost(n->addresses[m]->family, &n->addresses[m]->address)) { | |
229 | all_local_address = false; | |
230 | break; | |
231 | } | |
232 | ||
233 | if (!all_local_address) { | |
234 | in_order = false; | |
235 | break; | |
236 | } | |
237 | } | |
238 | ||
239 | if (!in_order) | |
240 | continue; | |
241 | ||
242 | STRV_FOREACH(i, item->names) { | |
243 | EtcHostsItemByName *n; | |
244 | ||
245 | n = hashmap_remove(hosts->by_name, *i); | |
246 | if (n) | |
247 | etc_hosts_item_by_name_free(n); | |
248 | } | |
249 | ||
250 | assert_se(hashmap_remove(hosts->by_address, local_in_addrs + j) == item); | |
133eedad | 251 | etc_hosts_item_by_address_free(item); |
9ca875e8 LP |
252 | } |
253 | } | |
254 | ||
78fc21a1 | 255 | int etc_hosts_parse(EtcHosts *hosts, FILE *f) { |
0f7bdf35 | 256 | _cleanup_(etc_hosts_clear) EtcHosts t = {}; |
37b7cc8d ZJS |
257 | unsigned nr = 0; |
258 | int r; | |
259 | ||
7c777a77 LP |
260 | for (;;) { |
261 | _cleanup_free_ char *line = NULL; | |
37b7cc8d ZJS |
262 | char *l; |
263 | ||
7c777a77 LP |
264 | r = read_line(f, LONG_LINE_MAX, &line); |
265 | if (r < 0) | |
266 | return log_error_errno(r, "Failed to read /etc/hosts: %m"); | |
267 | if (r == 0) | |
268 | break; | |
269 | ||
37b7cc8d ZJS |
270 | nr++; |
271 | ||
bd005277 ZJS |
272 | l = strchr(line, '#'); |
273 | if (l) | |
274 | *l = '\0'; | |
275 | ||
37b7cc8d ZJS |
276 | l = strstrip(line); |
277 | if (isempty(l)) | |
278 | continue; | |
37b7cc8d ZJS |
279 | |
280 | r = parse_line(&t, nr, l); | |
281 | if (r < 0) | |
282 | return r; | |
283 | } | |
284 | ||
9ca875e8 LP |
285 | strip_localhost(&t); |
286 | ||
0f7bdf35 | 287 | etc_hosts_clear(hosts); |
37b7cc8d ZJS |
288 | *hosts = t; |
289 | t = (EtcHosts) {}; /* prevent cleanup */ | |
290 | return 0; | |
291 | } | |
292 | ||
452ca091 | 293 | static int manager_etc_hosts_read(Manager *m) { |
dd0bc0f1 | 294 | _cleanup_fclose_ FILE *f = NULL; |
dd0bc0f1 LP |
295 | struct stat st; |
296 | usec_t ts; | |
dd0bc0f1 LP |
297 | int r; |
298 | ||
ba4e0427 | 299 | assert_se(sd_event_now(m->event, CLOCK_BOOTTIME, &ts) >= 0); |
dd0bc0f1 LP |
300 | |
301 | /* See if we checked /etc/hosts recently already */ | |
302 | if (m->etc_hosts_last != USEC_INFINITY && m->etc_hosts_last + ETC_HOSTS_RECHECK_USEC > ts) | |
303 | return 0; | |
304 | ||
305 | m->etc_hosts_last = ts; | |
306 | ||
36d892b7 | 307 | if (m->etc_hosts_stat.st_mode != 0) { |
dd0bc0f1 | 308 | if (stat("/etc/hosts", &st) < 0) { |
37b7cc8d ZJS |
309 | if (errno != ENOENT) |
310 | return log_error_errno(errno, "Failed to stat /etc/hosts: %m"); | |
dd0bc0f1 | 311 | |
37b7cc8d ZJS |
312 | manager_etc_hosts_flush(m); |
313 | return 0; | |
dd0bc0f1 LP |
314 | } |
315 | ||
aa5408e2 | 316 | /* Did the mtime or ino/dev change? If not, there's no point in re-reading the file. */ |
36d892b7 | 317 | if (stat_inode_unmodified(&m->etc_hosts_stat, &st)) |
dd0bc0f1 LP |
318 | return 0; |
319 | } | |
320 | ||
321 | f = fopen("/etc/hosts", "re"); | |
322 | if (!f) { | |
37b7cc8d ZJS |
323 | if (errno != ENOENT) |
324 | return log_error_errno(errno, "Failed to open /etc/hosts: %m"); | |
dd0bc0f1 | 325 | |
37b7cc8d ZJS |
326 | manager_etc_hosts_flush(m); |
327 | return 0; | |
dd0bc0f1 LP |
328 | } |
329 | ||
330 | /* Take the timestamp at the beginning of processing, so that any changes made later are read on the next | |
331 | * invocation */ | |
332 | r = fstat(fileno(f), &st); | |
333 | if (r < 0) | |
334 | return log_error_errno(errno, "Failed to fstat() /etc/hosts: %m"); | |
335 | ||
37b7cc8d | 336 | r = etc_hosts_parse(&m->etc_hosts, f); |
be19cdf3 | 337 | if (r < 0) |
37b7cc8d | 338 | return r; |
dd0bc0f1 | 339 | |
36d892b7 | 340 | m->etc_hosts_stat = st; |
dd0bc0f1 LP |
341 | m->etc_hosts_last = ts; |
342 | ||
343 | return 1; | |
dd0bc0f1 LP |
344 | } |
345 | ||
346 | int manager_etc_hosts_lookup(Manager *m, DnsQuestion* q, DnsAnswer **answer) { | |
347 | bool found_a = false, found_aaaa = false; | |
0351eb11 | 348 | struct in_addr_data k = {}; |
dd0bc0f1 | 349 | EtcHostsItemByName *bn; |
dd0bc0f1 LP |
350 | DnsResourceKey *t; |
351 | const char *name; | |
352 | unsigned i; | |
353 | int r; | |
354 | ||
355 | assert(m); | |
356 | assert(q); | |
357 | assert(answer); | |
358 | ||
86317087 YW |
359 | if (!m->read_etc_hosts) |
360 | return 0; | |
361 | ||
be19cdf3 | 362 | (void) manager_etc_hosts_read(m); |
dd0bc0f1 LP |
363 | |
364 | name = dns_question_first_name(q); | |
365 | if (!name) | |
366 | return 0; | |
367 | ||
368 | r = dns_name_address(name, &k.family, &k.address); | |
369 | if (r > 0) { | |
133eedad | 370 | EtcHostsItemByAddress *item; |
dd0bc0f1 LP |
371 | DnsResourceKey *found_ptr = NULL; |
372 | ||
37b7cc8d | 373 | item = hashmap_get(m->etc_hosts.by_address, &k); |
dd0bc0f1 LP |
374 | if (!item) |
375 | return 0; | |
376 | ||
377 | /* We have an address in /etc/hosts that matches the queried name. Let's return successful. Actual data | |
378 | * we'll only return if the request was for PTR. */ | |
379 | ||
380 | DNS_QUESTION_FOREACH(t, q) { | |
381 | if (!IN_SET(t->type, DNS_TYPE_PTR, DNS_TYPE_ANY)) | |
382 | continue; | |
383 | if (!IN_SET(t->class, DNS_CLASS_IN, DNS_CLASS_ANY)) | |
384 | continue; | |
385 | ||
1c02e7ba | 386 | r = dns_name_equal(dns_resource_key_name(t), name); |
dd0bc0f1 LP |
387 | if (r < 0) |
388 | return r; | |
389 | if (r > 0) { | |
390 | found_ptr = t; | |
391 | break; | |
392 | } | |
393 | } | |
394 | ||
395 | if (found_ptr) { | |
eb164c51 | 396 | r = dns_answer_reserve(answer, item->n_names); |
dd0bc0f1 LP |
397 | if (r < 0) |
398 | return r; | |
399 | ||
400 | STRV_FOREACH(n, item->names) { | |
401 | _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL; | |
402 | ||
403 | rr = dns_resource_record_new(found_ptr); | |
404 | if (!rr) | |
405 | return -ENOMEM; | |
406 | ||
407 | rr->ptr.name = strdup(*n); | |
408 | if (!rr->ptr.name) | |
409 | return -ENOMEM; | |
410 | ||
04617bf8 | 411 | r = dns_answer_add(*answer, rr, 0, DNS_ANSWER_AUTHENTICATED, NULL); |
dd0bc0f1 LP |
412 | if (r < 0) |
413 | return r; | |
414 | } | |
415 | } | |
416 | ||
417 | return 1; | |
418 | } | |
419 | ||
37b7cc8d | 420 | bn = hashmap_get(m->etc_hosts.by_name, name); |
fd373593 ZJS |
421 | if (bn) { |
422 | r = dns_answer_reserve(answer, bn->n_addresses); | |
423 | if (r < 0) | |
424 | return r; | |
425 | } else { | |
426 | /* Check if name was listed with no address. If yes, continue to return an answer. */ | |
427 | if (!set_contains(m->etc_hosts.no_address, name)) | |
428 | return 0; | |
429 | } | |
dd0bc0f1 LP |
430 | |
431 | DNS_QUESTION_FOREACH(t, q) { | |
432 | if (!IN_SET(t->type, DNS_TYPE_A, DNS_TYPE_AAAA, DNS_TYPE_ANY)) | |
433 | continue; | |
434 | if (!IN_SET(t->class, DNS_CLASS_IN, DNS_CLASS_ANY)) | |
435 | continue; | |
436 | ||
1c02e7ba | 437 | r = dns_name_equal(dns_resource_key_name(t), name); |
dd0bc0f1 LP |
438 | if (r < 0) |
439 | return r; | |
440 | if (r == 0) | |
441 | continue; | |
442 | ||
443 | if (IN_SET(t->type, DNS_TYPE_A, DNS_TYPE_ANY)) | |
444 | found_a = true; | |
445 | if (IN_SET(t->type, DNS_TYPE_AAAA, DNS_TYPE_ANY)) | |
446 | found_aaaa = true; | |
447 | ||
448 | if (found_a && found_aaaa) | |
449 | break; | |
450 | } | |
451 | ||
fd373593 | 452 | for (i = 0; bn && i < bn->n_addresses; i++) { |
dd0bc0f1 LP |
453 | _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL; |
454 | ||
0351eb11 YW |
455 | if ((!found_a && bn->addresses[i]->family == AF_INET) || |
456 | (!found_aaaa && bn->addresses[i]->family == AF_INET6)) | |
dd0bc0f1 LP |
457 | continue; |
458 | ||
0351eb11 | 459 | r = dns_resource_record_new_address(&rr, bn->addresses[i]->family, &bn->addresses[i]->address, bn->name); |
dd0bc0f1 LP |
460 | if (r < 0) |
461 | return r; | |
462 | ||
04617bf8 | 463 | r = dns_answer_add(*answer, rr, 0, DNS_ANSWER_AUTHENTICATED, NULL); |
dd0bc0f1 LP |
464 | if (r < 0) |
465 | return r; | |
466 | } | |
467 | ||
4050e04b | 468 | return found_a || found_aaaa; |
dd0bc0f1 | 469 | } |