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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 | ||
bb5c7730 YW |
21 | static EtcHostsItemByAddress *etc_hosts_item_by_address_free(EtcHostsItemByAddress *item) { |
22 | if (!item) | |
23 | return NULL; | |
24 | ||
37b7cc8d | 25 | strv_free(item->names); |
bb5c7730 | 26 | return mfree(item); |
37b7cc8d | 27 | } |
dd0bc0f1 | 28 | |
e4e34099 YW |
29 | DEFINE_TRIVIAL_CLEANUP_FUNC(EtcHostsItemByAddress*, etc_hosts_item_by_address_free); |
30 | ||
bb5c7730 YW |
31 | static EtcHostsItemByName *etc_hosts_item_by_name_free(EtcHostsItemByName *item) { |
32 | if (!item) | |
33 | return NULL; | |
34 | ||
37b7cc8d ZJS |
35 | free(item->name); |
36 | free(item->addresses); | |
bb5c7730 | 37 | return mfree(item); |
37b7cc8d | 38 | } |
dd0bc0f1 | 39 | |
e4e34099 YW |
40 | DEFINE_TRIVIAL_CLEANUP_FUNC(EtcHostsItemByName*, etc_hosts_item_by_name_free); |
41 | ||
0f7bdf35 YW |
42 | void etc_hosts_clear(EtcHosts *hosts) { |
43 | assert(hosts); | |
44 | ||
133eedad | 45 | hosts->by_address = hashmap_free_with_destructor(hosts->by_address, etc_hosts_item_by_address_free); |
37b7cc8d | 46 | hosts->by_name = hashmap_free_with_destructor(hosts->by_name, etc_hosts_item_by_name_free); |
fd373593 | 47 | hosts->no_address = set_free_free(hosts->no_address); |
37b7cc8d | 48 | } |
dd0bc0f1 | 49 | |
37b7cc8d | 50 | void manager_etc_hosts_flush(Manager *m) { |
0f7bdf35 | 51 | etc_hosts_clear(&m->etc_hosts); |
36d892b7 | 52 | m->etc_hosts_stat = (struct stat) {}; |
dd0bc0f1 LP |
53 | } |
54 | ||
37b7cc8d | 55 | static int parse_line(EtcHosts *hosts, unsigned nr, const char *line) { |
0351eb11 YW |
56 | _cleanup_free_ char *address_str = NULL; |
57 | struct in_addr_data address = {}; | |
fd373593 | 58 | bool found = false; |
133eedad | 59 | EtcHostsItemByAddress *item; |
dd0bc0f1 LP |
60 | int r; |
61 | ||
37b7cc8d | 62 | assert(hosts); |
0351eb11 | 63 | assert(line); |
dd0bc0f1 | 64 | |
0351eb11 YW |
65 | r = extract_first_word(&line, &address_str, NULL, EXTRACT_RELAX); |
66 | if (r < 0) | |
bd005277 ZJS |
67 | return log_error_errno(r, "/etc/hosts:%u: failed to extract address: %m", nr); |
68 | assert(r > 0); /* We already checked that the line is not empty, so it should contain *something* */ | |
0351eb11 | 69 | |
7bf8c3de | 70 | r = in_addr_ifindex_from_string_auto(address_str, &address.family, &address.address, NULL); |
bd005277 ZJS |
71 | if (r < 0) { |
72 | log_warning_errno(r, "/etc/hosts:%u: address '%s' is invalid, ignoring: %m", nr, address_str); | |
73 | return 0; | |
74 | } | |
0351eb11 | 75 | |
94876904 | 76 | r = in_addr_data_is_null(&address); |
bd005277 ZJS |
77 | if (r < 0) { |
78 | log_warning_errno(r, "/etc/hosts:%u: address '%s' is invalid, ignoring: %m", nr, address_str); | |
79 | return 0; | |
80 | } | |
dd0bc0f1 LP |
81 | if (r > 0) |
82 | /* This is an 0.0.0.0 or :: item, which we assume means that we shall map the specified hostname to | |
83 | * nothing. */ | |
84 | item = NULL; | |
85 | else { | |
78fc21a1 | 86 | /* If this is a normal address, then simply add entry mapping it to the specified names */ |
dd0bc0f1 | 87 | |
37b7cc8d | 88 | item = hashmap_get(hosts->by_address, &address); |
0351eb11 | 89 | if (!item) { |
e4e34099 | 90 | _cleanup_(etc_hosts_item_by_address_freep) EtcHostsItemByAddress *new_item = NULL; |
dd0bc0f1 | 91 | |
e4e34099 YW |
92 | new_item = new(EtcHostsItemByAddress, 1); |
93 | if (!new_item) | |
dd0bc0f1 LP |
94 | return log_oom(); |
95 | ||
e4e34099 | 96 | *new_item = (EtcHostsItemByAddress) { |
1ed31408 LP |
97 | .address = address, |
98 | }; | |
dd0bc0f1 | 99 | |
e4e34099 YW |
100 | r = hashmap_ensure_put(&hosts->by_address, &in_addr_data_hash_ops, &new_item->address, new_item); |
101 | if (r < 0) | |
dd0bc0f1 | 102 | return log_oom(); |
e4e34099 YW |
103 | |
104 | item = TAKE_PTR(new_item); | |
dd0bc0f1 LP |
105 | } |
106 | } | |
107 | ||
0351eb11 YW |
108 | for (;;) { |
109 | _cleanup_free_ char *name = NULL; | |
dd0bc0f1 LP |
110 | EtcHostsItemByName *bn; |
111 | ||
0351eb11 YW |
112 | r = extract_first_word(&line, &name, NULL, EXTRACT_RELAX); |
113 | if (r < 0) | |
38b38500 | 114 | return log_error_errno(r, "/etc/hosts:%u: couldn't extract hostname: %m", nr); |
0351eb11 YW |
115 | if (r == 0) |
116 | break; | |
117 | ||
7470cc4c | 118 | r = dns_name_is_valid_ldh(name); |
bd005277 | 119 | if (r <= 0) { |
98b1eb71 YW |
120 | if (r < 0) |
121 | log_warning_errno(r, "/etc/hosts:%u: Failed to check the validity of hostname \"%s\", ignoring: %m", nr, name); | |
122 | else | |
123 | log_warning("/etc/hosts:%u: hostname \"%s\" is not valid, ignoring.", nr, name); | |
bd005277 ZJS |
124 | continue; |
125 | } | |
126 | ||
10b0c818 YW |
127 | found = true; |
128 | ||
fd373593 ZJS |
129 | if (!item) { |
130 | /* Optimize the case where we don't need to store any addresses, by storing | |
131 | * only the name in a dedicated Set instead of the hashmap */ | |
132 | ||
ab9dd0b9 | 133 | r = set_ensure_consume(&hosts->no_address, &dns_name_hash_ops, TAKE_PTR(name)); |
fd373593 | 134 | if (r < 0) |
10b0c818 | 135 | return log_oom(); |
fd373593 | 136 | |
fd373593 | 137 | continue; |
0351eb11 YW |
138 | } |
139 | ||
eb164c51 | 140 | r = strv_extend_with_size(&item->names, &item->n_names, name); |
fd373593 ZJS |
141 | if (r < 0) |
142 | return log_oom(); | |
143 | ||
37b7cc8d | 144 | bn = hashmap_get(hosts->by_name, name); |
dd0bc0f1 | 145 | if (!bn) { |
e4e34099 | 146 | _cleanup_(etc_hosts_item_by_name_freep) EtcHostsItemByName *new_item = NULL; |
dd0bc0f1 | 147 | |
e4e34099 YW |
148 | new_item = new(EtcHostsItemByName, 1); |
149 | if (!new_item) | |
dd0bc0f1 LP |
150 | return log_oom(); |
151 | ||
e4e34099 YW |
152 | *new_item = (EtcHostsItemByName) { |
153 | .name = TAKE_PTR(name), | |
154 | }; | |
155 | ||
156 | r = hashmap_ensure_put(&hosts->by_name, &dns_name_hash_ops, new_item->name, new_item); | |
157 | if (r < 0) | |
dd0bc0f1 | 158 | return log_oom(); |
0351eb11 | 159 | |
e4e34099 | 160 | bn = TAKE_PTR(new_item); |
dd0bc0f1 LP |
161 | } |
162 | ||
319a4f4b | 163 | if (!GREEDY_REALLOC(bn->addresses, bn->n_addresses + 1)) |
fd373593 | 164 | return log_oom(); |
dd0bc0f1 | 165 | |
fd373593 | 166 | bn->addresses[bn->n_addresses++] = &item->address; |
dd0bc0f1 LP |
167 | } |
168 | ||
baaa35ad | 169 | if (!found) |
10b0c818 | 170 | log_warning("/etc/hosts:%u: line is missing any valid hostnames", nr); |
dd0bc0f1 | 171 | |
0351eb11 | 172 | return 0; |
dd0bc0f1 LP |
173 | } |
174 | ||
9ca875e8 LP |
175 | static void strip_localhost(EtcHosts *hosts) { |
176 | static const struct in_addr_data local_in_addrs[] = { | |
177 | { | |
178 | .family = AF_INET, | |
179 | #if __BYTE_ORDER == __LITTLE_ENDIAN | |
180 | /* We want constant expressions here, that's why we don't use htole32() here */ | |
181 | .address.in.s_addr = UINT32_C(0x0100007F), | |
182 | #else | |
183 | .address.in.s_addr = UINT32_C(0x7F000001), | |
184 | #endif | |
185 | }, | |
186 | { | |
187 | .family = AF_INET6, | |
188 | .address.in6 = IN6ADDR_LOOPBACK_INIT, | |
189 | }, | |
190 | }; | |
191 | ||
9ca875e8 LP |
192 | assert(hosts); |
193 | ||
194 | /* Removes the 'localhost' entry from what we loaded. But only if the mapping is exclusively between | |
195 | * 127.0.0.1 and localhost (or aliases to that we recognize). If there's any other name assigned to | |
196 | * it, we leave the entry in. | |
197 | * | |
198 | * This way our regular synthesizing can take over, but only if it would result in the exact same | |
199 | * mappings. */ | |
200 | ||
201 | for (size_t j = 0; j < ELEMENTSOF(local_in_addrs); j++) { | |
9f1a1f20 YW |
202 | bool all_localhost, all_local_address; |
203 | EtcHostsItemByAddress *item; | |
9ca875e8 LP |
204 | |
205 | item = hashmap_get(hosts->by_address, local_in_addrs + j); | |
206 | if (!item) | |
207 | continue; | |
208 | ||
209 | /* Check whether all hostnames the loopback address points to are localhost ones */ | |
210 | all_localhost = true; | |
211 | STRV_FOREACH(i, item->names) | |
212 | if (!is_localhost(*i)) { | |
213 | all_localhost = false; | |
214 | break; | |
215 | } | |
216 | ||
217 | if (!all_localhost) /* Not all names are localhost, hence keep the entries for this address. */ | |
218 | continue; | |
219 | ||
220 | /* Now check if the names listed for this address actually all point back just to this | |
221 | * address (or the other loopback address). If not, let's stay away from this too. */ | |
9f1a1f20 | 222 | all_local_address = true; |
9ca875e8 LP |
223 | STRV_FOREACH(i, item->names) { |
224 | EtcHostsItemByName *n; | |
9ca875e8 LP |
225 | |
226 | n = hashmap_get(hosts->by_name, *i); | |
227 | if (!n) /* No reverse entry? Then almost certainly the entry already got deleted from | |
228 | * the previous iteration of this loop, i.e. via the other protocol */ | |
229 | break; | |
230 | ||
231 | /* Now check if the addresses of this item are all localhost addresses */ | |
9ca875e8 LP |
232 | for (size_t m = 0; m < n->n_addresses; m++) |
233 | if (!in_addr_is_localhost(n->addresses[m]->family, &n->addresses[m]->address)) { | |
234 | all_local_address = false; | |
235 | break; | |
236 | } | |
237 | ||
9f1a1f20 | 238 | if (!all_local_address) |
9ca875e8 | 239 | break; |
9ca875e8 LP |
240 | } |
241 | ||
9f1a1f20 | 242 | if (!all_local_address) |
9ca875e8 LP |
243 | continue; |
244 | ||
bb5c7730 YW |
245 | STRV_FOREACH(i, item->names) |
246 | etc_hosts_item_by_name_free(hashmap_remove(hosts->by_name, *i)); | |
9ca875e8 LP |
247 | |
248 | assert_se(hashmap_remove(hosts->by_address, local_in_addrs + j) == item); | |
133eedad | 249 | etc_hosts_item_by_address_free(item); |
9ca875e8 LP |
250 | } |
251 | } | |
252 | ||
78fc21a1 | 253 | int etc_hosts_parse(EtcHosts *hosts, FILE *f) { |
0f7bdf35 | 254 | _cleanup_(etc_hosts_clear) EtcHosts t = {}; |
37b7cc8d ZJS |
255 | unsigned nr = 0; |
256 | int r; | |
257 | ||
7c777a77 LP |
258 | for (;;) { |
259 | _cleanup_free_ char *line = NULL; | |
37b7cc8d ZJS |
260 | char *l; |
261 | ||
7c777a77 LP |
262 | r = read_line(f, LONG_LINE_MAX, &line); |
263 | if (r < 0) | |
264 | return log_error_errno(r, "Failed to read /etc/hosts: %m"); | |
265 | if (r == 0) | |
266 | break; | |
267 | ||
37b7cc8d ZJS |
268 | nr++; |
269 | ||
bd005277 ZJS |
270 | l = strchr(line, '#'); |
271 | if (l) | |
272 | *l = '\0'; | |
273 | ||
37b7cc8d ZJS |
274 | l = strstrip(line); |
275 | if (isempty(l)) | |
276 | continue; | |
37b7cc8d ZJS |
277 | |
278 | r = parse_line(&t, nr, l); | |
279 | if (r < 0) | |
280 | return r; | |
281 | } | |
282 | ||
9ca875e8 LP |
283 | strip_localhost(&t); |
284 | ||
0f7bdf35 | 285 | etc_hosts_clear(hosts); |
37b7cc8d ZJS |
286 | *hosts = t; |
287 | t = (EtcHosts) {}; /* prevent cleanup */ | |
288 | return 0; | |
289 | } | |
290 | ||
452ca091 | 291 | static int manager_etc_hosts_read(Manager *m) { |
dd0bc0f1 | 292 | _cleanup_fclose_ FILE *f = NULL; |
dd0bc0f1 LP |
293 | struct stat st; |
294 | usec_t ts; | |
dd0bc0f1 LP |
295 | int r; |
296 | ||
ba4e0427 | 297 | assert_se(sd_event_now(m->event, CLOCK_BOOTTIME, &ts) >= 0); |
dd0bc0f1 LP |
298 | |
299 | /* See if we checked /etc/hosts recently already */ | |
300 | if (m->etc_hosts_last != USEC_INFINITY && m->etc_hosts_last + ETC_HOSTS_RECHECK_USEC > ts) | |
301 | return 0; | |
302 | ||
303 | m->etc_hosts_last = ts; | |
304 | ||
36d892b7 | 305 | if (m->etc_hosts_stat.st_mode != 0) { |
dd0bc0f1 | 306 | if (stat("/etc/hosts", &st) < 0) { |
37b7cc8d ZJS |
307 | if (errno != ENOENT) |
308 | return log_error_errno(errno, "Failed to stat /etc/hosts: %m"); | |
dd0bc0f1 | 309 | |
37b7cc8d ZJS |
310 | manager_etc_hosts_flush(m); |
311 | return 0; | |
dd0bc0f1 LP |
312 | } |
313 | ||
aa5408e2 | 314 | /* Did the mtime or ino/dev change? If not, there's no point in re-reading the file. */ |
36d892b7 | 315 | if (stat_inode_unmodified(&m->etc_hosts_stat, &st)) |
dd0bc0f1 LP |
316 | return 0; |
317 | } | |
318 | ||
319 | f = fopen("/etc/hosts", "re"); | |
320 | if (!f) { | |
37b7cc8d ZJS |
321 | if (errno != ENOENT) |
322 | return log_error_errno(errno, "Failed to open /etc/hosts: %m"); | |
dd0bc0f1 | 323 | |
37b7cc8d ZJS |
324 | manager_etc_hosts_flush(m); |
325 | return 0; | |
dd0bc0f1 LP |
326 | } |
327 | ||
328 | /* Take the timestamp at the beginning of processing, so that any changes made later are read on the next | |
329 | * invocation */ | |
330 | r = fstat(fileno(f), &st); | |
331 | if (r < 0) | |
332 | return log_error_errno(errno, "Failed to fstat() /etc/hosts: %m"); | |
333 | ||
37b7cc8d | 334 | r = etc_hosts_parse(&m->etc_hosts, f); |
be19cdf3 | 335 | if (r < 0) |
37b7cc8d | 336 | return r; |
dd0bc0f1 | 337 | |
36d892b7 | 338 | m->etc_hosts_stat = st; |
dd0bc0f1 LP |
339 | m->etc_hosts_last = ts; |
340 | ||
341 | return 1; | |
dd0bc0f1 LP |
342 | } |
343 | ||
344 | int manager_etc_hosts_lookup(Manager *m, DnsQuestion* q, DnsAnswer **answer) { | |
345 | bool found_a = false, found_aaaa = false; | |
0351eb11 | 346 | struct in_addr_data k = {}; |
dd0bc0f1 | 347 | EtcHostsItemByName *bn; |
dd0bc0f1 LP |
348 | DnsResourceKey *t; |
349 | const char *name; | |
350 | unsigned i; | |
351 | int r; | |
352 | ||
353 | assert(m); | |
354 | assert(q); | |
355 | assert(answer); | |
356 | ||
86317087 YW |
357 | if (!m->read_etc_hosts) |
358 | return 0; | |
359 | ||
be19cdf3 | 360 | (void) manager_etc_hosts_read(m); |
dd0bc0f1 LP |
361 | |
362 | name = dns_question_first_name(q); | |
363 | if (!name) | |
364 | return 0; | |
365 | ||
366 | r = dns_name_address(name, &k.family, &k.address); | |
367 | if (r > 0) { | |
133eedad | 368 | EtcHostsItemByAddress *item; |
dd0bc0f1 LP |
369 | DnsResourceKey *found_ptr = NULL; |
370 | ||
37b7cc8d | 371 | item = hashmap_get(m->etc_hosts.by_address, &k); |
dd0bc0f1 LP |
372 | if (!item) |
373 | return 0; | |
374 | ||
375 | /* We have an address in /etc/hosts that matches the queried name. Let's return successful. Actual data | |
376 | * we'll only return if the request was for PTR. */ | |
377 | ||
378 | DNS_QUESTION_FOREACH(t, q) { | |
379 | if (!IN_SET(t->type, DNS_TYPE_PTR, DNS_TYPE_ANY)) | |
380 | continue; | |
381 | if (!IN_SET(t->class, DNS_CLASS_IN, DNS_CLASS_ANY)) | |
382 | continue; | |
383 | ||
1c02e7ba | 384 | r = dns_name_equal(dns_resource_key_name(t), name); |
dd0bc0f1 LP |
385 | if (r < 0) |
386 | return r; | |
387 | if (r > 0) { | |
388 | found_ptr = t; | |
389 | break; | |
390 | } | |
391 | } | |
392 | ||
393 | if (found_ptr) { | |
eb164c51 | 394 | r = dns_answer_reserve(answer, item->n_names); |
dd0bc0f1 LP |
395 | if (r < 0) |
396 | return r; | |
397 | ||
398 | STRV_FOREACH(n, item->names) { | |
399 | _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL; | |
400 | ||
401 | rr = dns_resource_record_new(found_ptr); | |
402 | if (!rr) | |
403 | return -ENOMEM; | |
404 | ||
405 | rr->ptr.name = strdup(*n); | |
406 | if (!rr->ptr.name) | |
407 | return -ENOMEM; | |
408 | ||
04617bf8 | 409 | r = dns_answer_add(*answer, rr, 0, DNS_ANSWER_AUTHENTICATED, NULL); |
dd0bc0f1 LP |
410 | if (r < 0) |
411 | return r; | |
412 | } | |
413 | } | |
414 | ||
415 | return 1; | |
416 | } | |
417 | ||
37b7cc8d | 418 | bn = hashmap_get(m->etc_hosts.by_name, name); |
fd373593 ZJS |
419 | if (bn) { |
420 | r = dns_answer_reserve(answer, bn->n_addresses); | |
421 | if (r < 0) | |
422 | return r; | |
423 | } else { | |
424 | /* Check if name was listed with no address. If yes, continue to return an answer. */ | |
425 | if (!set_contains(m->etc_hosts.no_address, name)) | |
426 | return 0; | |
427 | } | |
dd0bc0f1 LP |
428 | |
429 | DNS_QUESTION_FOREACH(t, q) { | |
430 | if (!IN_SET(t->type, DNS_TYPE_A, DNS_TYPE_AAAA, DNS_TYPE_ANY)) | |
431 | continue; | |
432 | if (!IN_SET(t->class, DNS_CLASS_IN, DNS_CLASS_ANY)) | |
433 | continue; | |
434 | ||
1c02e7ba | 435 | r = dns_name_equal(dns_resource_key_name(t), name); |
dd0bc0f1 LP |
436 | if (r < 0) |
437 | return r; | |
438 | if (r == 0) | |
439 | continue; | |
440 | ||
441 | if (IN_SET(t->type, DNS_TYPE_A, DNS_TYPE_ANY)) | |
442 | found_a = true; | |
443 | if (IN_SET(t->type, DNS_TYPE_AAAA, DNS_TYPE_ANY)) | |
444 | found_aaaa = true; | |
445 | ||
446 | if (found_a && found_aaaa) | |
447 | break; | |
448 | } | |
449 | ||
fd373593 | 450 | for (i = 0; bn && i < bn->n_addresses; i++) { |
dd0bc0f1 LP |
451 | _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL; |
452 | ||
0351eb11 YW |
453 | if ((!found_a && bn->addresses[i]->family == AF_INET) || |
454 | (!found_aaaa && bn->addresses[i]->family == AF_INET6)) | |
dd0bc0f1 LP |
455 | continue; |
456 | ||
0351eb11 | 457 | r = dns_resource_record_new_address(&rr, bn->addresses[i]->family, &bn->addresses[i]->address, bn->name); |
dd0bc0f1 LP |
458 | if (r < 0) |
459 | return r; | |
460 | ||
04617bf8 | 461 | r = dns_answer_add(*answer, rr, 0, DNS_ANSWER_AUTHENTICATED, NULL); |
dd0bc0f1 LP |
462 | if (r < 0) |
463 | return r; | |
464 | } | |
465 | ||
4050e04b | 466 | return found_a || found_aaaa; |
dd0bc0f1 | 467 | } |