1 | /* Copyright (C) 1996-2018 Free Software Foundation, Inc. |
2 | This file is part of the GNU C Library. |
3 | Extended from original form by Ulrich Drepper <drepper@cygnus.com>, 1996. |
4 | |
5 | The GNU C Library is free software; you can redistribute it and/or |
6 | modify it under the terms of the GNU Lesser General Public |
7 | License as published by the Free Software Foundation; either |
8 | version 2.1 of the License, or (at your option) any later version. |
9 | |
10 | The GNU C Library is distributed in the hope that it will be useful, |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
13 | Lesser General Public License for more details. |
14 | |
15 | You should have received a copy of the GNU Lesser General Public |
16 | License along with the GNU C Library; if not, see |
17 | <http://www.gnu.org/licenses/>. */ |
18 | |
19 | /* Parts of this file are plain copies of the file `gethtnamadr.c' from |
20 | the bind package and it has the following copyright. */ |
21 | |
22 | /* |
23 | * ++Copyright++ 1985, 1988, 1993 |
24 | * - |
25 | * Copyright (c) 1985, 1988, 1993 |
26 | * The Regents of the University of California. All rights reserved. |
27 | * |
28 | * Redistribution and use in source and binary forms, with or without |
29 | * modification, are permitted provided that the following conditions |
30 | * are met: |
31 | * 1. Redistributions of source code must retain the above copyright |
32 | * notice, this list of conditions and the following disclaimer. |
33 | * 2. Redistributions in binary form must reproduce the above copyright |
34 | * notice, this list of conditions and the following disclaimer in the |
35 | * documentation and/or other materials provided with the distribution. |
36 | * 4. Neither the name of the University nor the names of its contributors |
37 | * may be used to endorse or promote products derived from this software |
38 | * without specific prior written permission. |
39 | * |
40 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
41 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
42 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
43 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
44 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
45 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
46 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
47 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
48 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
49 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
50 | * SUCH DAMAGE. |
51 | * - |
52 | * Portions Copyright (c) 1993 by Digital Equipment Corporation. |
53 | * |
54 | * Permission to use, copy, modify, and distribute this software for any |
55 | * purpose with or without fee is hereby granted, provided that the above |
56 | * copyright notice and this permission notice appear in all copies, and that |
57 | * the name of Digital Equipment Corporation not be used in advertising or |
58 | * publicity pertaining to distribution of the document or software without |
59 | * specific, written prior permission. |
60 | * |
61 | * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL |
62 | * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES |
63 | * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT |
64 | * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL |
65 | * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR |
66 | * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS |
67 | * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS |
68 | * SOFTWARE. |
69 | * - |
70 | * --Copyright-- |
71 | */ |
72 | |
73 | #include <assert.h> |
74 | #include <ctype.h> |
75 | #include <errno.h> |
76 | #include <netdb.h> |
77 | #include <stdio.h> |
78 | #include <stdlib.h> |
79 | #include <stddef.h> |
80 | #include <string.h> |
81 | |
82 | #include "nsswitch.h" |
83 | #include <arpa/nameser.h> |
84 | |
85 | #include <resolv/resolv-internal.h> |
86 | #include <resolv/resolv_context.h> |
87 | |
88 | /* Get implementations of some internal functions. */ |
89 | #include <resolv/mapv4v6addr.h> |
90 | #include <resolv/mapv4v6hostent.h> |
91 | |
92 | #define RESOLVSORT |
93 | |
94 | #if PACKETSZ > 65536 |
95 | # define MAXPACKET PACKETSZ |
96 | #else |
97 | # define MAXPACKET 65536 |
98 | #endif |
99 | /* As per RFC 1034 and 1035 a host name cannot exceed 255 octets in length. */ |
100 | #ifdef MAXHOSTNAMELEN |
101 | # undef MAXHOSTNAMELEN |
102 | #endif |
103 | #define MAXHOSTNAMELEN 256 |
104 | |
105 | /* We need this time later. */ |
106 | typedef union querybuf |
107 | { |
108 | HEADER hdr; |
109 | u_char buf[MAXPACKET]; |
110 | } querybuf; |
111 | |
112 | static enum nss_status getanswer_r (struct resolv_context *ctx, |
113 | const querybuf *answer, int anslen, |
114 | const char *qname, int qtype, |
115 | struct hostent *result, char *buffer, |
116 | size_t buflen, int *errnop, int *h_errnop, |
117 | int map, int32_t *ttlp, char **canonp); |
118 | |
119 | static enum nss_status gaih_getanswer (const querybuf *answer1, int anslen1, |
120 | const querybuf *answer2, int anslen2, |
121 | const char *qname, |
122 | struct gaih_addrtuple **pat, |
123 | char *buffer, size_t buflen, |
124 | int *errnop, int *h_errnop, |
125 | int32_t *ttlp); |
126 | |
127 | static enum nss_status gethostbyname3_context (struct resolv_context *ctx, |
128 | const char *name, int af, |
129 | struct hostent *result, |
130 | char *buffer, size_t buflen, |
131 | int *errnop, int *h_errnop, |
132 | int32_t *ttlp, |
133 | char **canonp); |
134 | |
135 | /* Return the expected RDATA length for an address record type (A or |
136 | AAAA). */ |
137 | static int |
138 | rrtype_to_rdata_length (int type) |
139 | { |
140 | switch (type) |
141 | { |
142 | case T_A: |
143 | return INADDRSZ; |
144 | case T_AAAA: |
145 | return IN6ADDRSZ; |
146 | default: |
147 | return -1; |
148 | } |
149 | } |
150 | |
151 | |
152 | enum nss_status |
153 | _nss_dns_gethostbyname3_r (const char *name, int af, struct hostent *result, |
154 | char *buffer, size_t buflen, int *errnop, |
155 | int *h_errnop, int32_t *ttlp, char **canonp) |
156 | { |
157 | struct resolv_context *ctx = __resolv_context_get (); |
158 | if (ctx == NULL) |
159 | { |
160 | *errnop = errno; |
161 | *h_errnop = NETDB_INTERNAL; |
162 | return NSS_STATUS_UNAVAIL; |
163 | } |
164 | enum nss_status status = gethostbyname3_context |
165 | (ctx, name, af, result, buffer, buflen, errnop, h_errnop, ttlp, canonp); |
166 | __resolv_context_put (ctx); |
167 | return status; |
168 | } |
169 | |
170 | static enum nss_status |
171 | gethostbyname3_context (struct resolv_context *ctx, |
172 | const char *name, int af, struct hostent *result, |
173 | char *buffer, size_t buflen, int *errnop, |
174 | int *h_errnop, int32_t *ttlp, char **canonp) |
175 | { |
176 | union |
177 | { |
178 | querybuf *buf; |
179 | u_char *ptr; |
180 | } host_buffer; |
181 | querybuf *orig_host_buffer; |
182 | char tmp[NS_MAXDNAME]; |
183 | int size, type, n; |
184 | const char *cp; |
185 | int map = 0; |
186 | int olderr = errno; |
187 | enum nss_status status; |
188 | |
189 | switch (af) { |
190 | case AF_INET: |
191 | size = INADDRSZ; |
192 | type = T_A; |
193 | break; |
194 | case AF_INET6: |
195 | size = IN6ADDRSZ; |
196 | type = T_AAAA; |
197 | break; |
198 | default: |
199 | *h_errnop = NO_DATA; |
200 | *errnop = EAFNOSUPPORT; |
201 | return NSS_STATUS_UNAVAIL; |
202 | } |
203 | |
204 | result->h_addrtype = af; |
205 | result->h_length = size; |
206 | |
207 | /* |
208 | * if there aren't any dots, it could be a user-level alias. |
209 | * this is also done in res_query() since we are not the only |
210 | * function that looks up host names. |
211 | */ |
212 | if (strchr (name, '.') == NULL |
213 | && (cp = __res_context_hostalias (ctx, name, tmp, sizeof (tmp))) != NULL) |
214 | name = cp; |
215 | |
216 | host_buffer.buf = orig_host_buffer = (querybuf *) alloca (1024); |
217 | |
218 | n = __res_context_search (ctx, name, C_IN, type, host_buffer.buf->buf, |
219 | 1024, &host_buffer.ptr, NULL, NULL, NULL, NULL); |
220 | if (n < 0) |
221 | { |
222 | switch (errno) |
223 | { |
224 | case ESRCH: |
225 | status = NSS_STATUS_TRYAGAIN; |
226 | h_errno = TRY_AGAIN; |
227 | break; |
228 | /* System has run out of file descriptors. */ |
229 | case EMFILE: |
230 | case ENFILE: |
231 | h_errno = NETDB_INTERNAL; |
232 | /* Fall through. */ |
233 | case ECONNREFUSED: |
234 | case ETIMEDOUT: |
235 | status = NSS_STATUS_UNAVAIL; |
236 | break; |
237 | default: |
238 | status = NSS_STATUS_NOTFOUND; |
239 | break; |
240 | } |
241 | *h_errnop = h_errno; |
242 | if (h_errno == TRY_AGAIN) |
243 | *errnop = EAGAIN; |
244 | else |
245 | __set_errno (olderr); |
246 | |
247 | /* If we are looking for an IPv6 address and mapping is enabled |
248 | by having the RES_USE_INET6 bit in _res.options set, we try |
249 | another lookup. */ |
250 | if (af == AF_INET6 && res_use_inet6 ()) |
251 | n = __res_context_search (ctx, name, C_IN, T_A, host_buffer.buf->buf, |
252 | host_buffer.buf != orig_host_buffer |
253 | ? MAXPACKET : 1024, &host_buffer.ptr, |
254 | NULL, NULL, NULL, NULL); |
255 | |
256 | if (n < 0) |
257 | { |
258 | if (host_buffer.buf != orig_host_buffer) |
259 | free (host_buffer.buf); |
260 | return status; |
261 | } |
262 | |
263 | map = 1; |
264 | |
265 | result->h_addrtype = AF_INET; |
266 | result->h_length = INADDRSZ; |
267 | } |
268 | |
269 | status = getanswer_r |
270 | (ctx, host_buffer.buf, n, name, type, result, buffer, buflen, |
271 | errnop, h_errnop, map, ttlp, canonp); |
272 | if (host_buffer.buf != orig_host_buffer) |
273 | free (host_buffer.buf); |
274 | return status; |
275 | } |
276 | |
277 | enum nss_status |
278 | _nss_dns_gethostbyname2_r (const char *name, int af, struct hostent *result, |
279 | char *buffer, size_t buflen, int *errnop, |
280 | int *h_errnop) |
281 | { |
282 | return _nss_dns_gethostbyname3_r (name, af, result, buffer, buflen, errnop, |
283 | h_errnop, NULL, NULL); |
284 | } |
285 | |
286 | |
287 | enum nss_status |
288 | _nss_dns_gethostbyname_r (const char *name, struct hostent *result, |
289 | char *buffer, size_t buflen, int *errnop, |
290 | int *h_errnop) |
291 | { |
292 | struct resolv_context *ctx = __resolv_context_get (); |
293 | if (ctx == NULL) |
294 | { |
295 | *errnop = errno; |
296 | *h_errnop = NETDB_INTERNAL; |
297 | return NSS_STATUS_UNAVAIL; |
298 | } |
299 | enum nss_status status = NSS_STATUS_NOTFOUND; |
300 | if (res_use_inet6 ()) |
301 | status = gethostbyname3_context (ctx, name, AF_INET6, result, buffer, |
302 | buflen, errnop, h_errnop, NULL, NULL); |
303 | if (status == NSS_STATUS_NOTFOUND) |
304 | status = gethostbyname3_context (ctx, name, AF_INET, result, buffer, |
305 | buflen, errnop, h_errnop, NULL, NULL); |
306 | __resolv_context_put (ctx); |
307 | return status; |
308 | } |
309 | |
310 | |
311 | enum nss_status |
312 | _nss_dns_gethostbyname4_r (const char *name, struct gaih_addrtuple **pat, |
313 | char *buffer, size_t buflen, int *errnop, |
314 | int *herrnop, int32_t *ttlp) |
315 | { |
316 | struct resolv_context *ctx = __resolv_context_get (); |
317 | if (ctx == NULL) |
318 | { |
319 | *errnop = errno; |
320 | *herrnop = NETDB_INTERNAL; |
321 | return NSS_STATUS_UNAVAIL; |
322 | } |
323 | |
324 | /* |
325 | * if there aren't any dots, it could be a user-level alias. |
326 | * this is also done in res_query() since we are not the only |
327 | * function that looks up host names. |
328 | */ |
329 | if (strchr (name, '.') == NULL) |
330 | { |
331 | char *tmp = alloca (NS_MAXDNAME); |
332 | const char *cp = __res_context_hostalias (ctx, name, tmp, NS_MAXDNAME); |
333 | if (cp != NULL) |
334 | name = cp; |
335 | } |
336 | |
337 | union |
338 | { |
339 | querybuf *buf; |
340 | u_char *ptr; |
341 | } host_buffer; |
342 | querybuf *orig_host_buffer; |
343 | host_buffer.buf = orig_host_buffer = (querybuf *) alloca (2048); |
344 | u_char *ans2p = NULL; |
345 | int nans2p = 0; |
346 | int resplen2 = 0; |
347 | int ans2p_malloced = 0; |
348 | |
349 | int olderr = errno; |
350 | enum nss_status status; |
351 | int n = __res_context_search (ctx, name, C_IN, T_QUERY_A_AND_AAAA, |
352 | host_buffer.buf->buf, 2048, &host_buffer.ptr, |
353 | &ans2p, &nans2p, &resplen2, &ans2p_malloced); |
354 | if (n >= 0) |
355 | { |
356 | status = gaih_getanswer (host_buffer.buf, n, (const querybuf *) ans2p, |
357 | resplen2, name, pat, buffer, buflen, |
358 | errnop, herrnop, ttlp); |
359 | } |
360 | else |
361 | { |
362 | switch (errno) |
363 | { |
364 | case ESRCH: |
365 | status = NSS_STATUS_TRYAGAIN; |
366 | h_errno = TRY_AGAIN; |
367 | break; |
368 | /* System has run out of file descriptors. */ |
369 | case EMFILE: |
370 | case ENFILE: |
371 | h_errno = NETDB_INTERNAL; |
372 | /* Fall through. */ |
373 | case ECONNREFUSED: |
374 | case ETIMEDOUT: |
375 | status = NSS_STATUS_UNAVAIL; |
376 | break; |
377 | default: |
378 | status = NSS_STATUS_NOTFOUND; |
379 | break; |
380 | } |
381 | |
382 | *herrnop = h_errno; |
383 | if (h_errno == TRY_AGAIN) |
384 | *errnop = EAGAIN; |
385 | else |
386 | __set_errno (olderr); |
387 | } |
388 | |
389 | /* Check whether ans2p was separately allocated. */ |
390 | if (ans2p_malloced) |
391 | free (ans2p); |
392 | |
393 | if (host_buffer.buf != orig_host_buffer) |
394 | free (host_buffer.buf); |
395 | |
396 | __resolv_context_put (ctx); |
397 | return status; |
398 | } |
399 | |
400 | |
401 | extern enum nss_status _nss_dns_gethostbyaddr2_r (const void *addr, |
402 | socklen_t len, int af, |
403 | struct hostent *result, |
404 | char *buffer, size_t buflen, |
405 | int *errnop, int *h_errnop, |
406 | int32_t *ttlp); |
407 | hidden_proto (_nss_dns_gethostbyaddr2_r) |
408 | |
409 | enum nss_status |
410 | _nss_dns_gethostbyaddr2_r (const void *addr, socklen_t len, int af, |
411 | struct hostent *result, char *buffer, size_t buflen, |
412 | int *errnop, int *h_errnop, int32_t *ttlp) |
413 | { |
414 | static const u_char mapped[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0xff,0xff }; |
415 | static const u_char tunnelled[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0,0 }; |
416 | static const u_char v6local[] = { 0,0, 0,1 }; |
417 | const u_char *uaddr = (const u_char *)addr; |
418 | struct host_data |
419 | { |
420 | char *aliases[MAX_NR_ALIASES]; |
421 | unsigned char host_addr[16]; /* IPv4 or IPv6 */ |
422 | char *h_addr_ptrs[MAX_NR_ADDRS + 1]; |
423 | char linebuffer[0]; |
424 | } *host_data = (struct host_data *) buffer; |
425 | union |
426 | { |
427 | querybuf *buf; |
428 | u_char *ptr; |
429 | } host_buffer; |
430 | querybuf *orig_host_buffer; |
431 | char qbuf[MAXDNAME+1], *qp = NULL; |
432 | size_t size; |
433 | int n, status; |
434 | int olderr = errno; |
435 | |
436 | uintptr_t pad = -(uintptr_t) buffer % __alignof__ (struct host_data); |
437 | buffer += pad; |
438 | buflen = buflen > pad ? buflen - pad : 0; |
439 | |
440 | if (__glibc_unlikely (buflen < sizeof (struct host_data))) |
441 | { |
442 | *errnop = ERANGE; |
443 | *h_errnop = NETDB_INTERNAL; |
444 | return NSS_STATUS_TRYAGAIN; |
445 | } |
446 | |
447 | host_data = (struct host_data *) buffer; |
448 | |
449 | struct resolv_context *ctx = __resolv_context_get (); |
450 | if (ctx == NULL) |
451 | { |
452 | *errnop = errno; |
453 | *h_errnop = NETDB_INTERNAL; |
454 | return NSS_STATUS_UNAVAIL; |
455 | } |
456 | |
457 | if (af == AF_INET6 && len == IN6ADDRSZ |
458 | && (memcmp (uaddr, mapped, sizeof mapped) == 0 |
459 | || (memcmp (uaddr, tunnelled, sizeof tunnelled) == 0 |
460 | && memcmp (&uaddr[sizeof tunnelled], v6local, sizeof v6local)))) |
461 | { |
462 | /* Unmap. */ |
463 | addr += sizeof mapped; |
464 | uaddr += sizeof mapped; |
465 | af = AF_INET; |
466 | len = INADDRSZ; |
467 | } |
468 | |
469 | switch (af) |
470 | { |
471 | case AF_INET: |
472 | size = INADDRSZ; |
473 | break; |
474 | case AF_INET6: |
475 | size = IN6ADDRSZ; |
476 | break; |
477 | default: |
478 | *errnop = EAFNOSUPPORT; |
479 | *h_errnop = NETDB_INTERNAL; |
480 | __resolv_context_put (ctx); |
481 | return NSS_STATUS_UNAVAIL; |
482 | } |
483 | if (size > len) |
484 | { |
485 | *errnop = EAFNOSUPPORT; |
486 | *h_errnop = NETDB_INTERNAL; |
487 | __resolv_context_put (ctx); |
488 | return NSS_STATUS_UNAVAIL; |
489 | } |
490 | |
491 | host_buffer.buf = orig_host_buffer = (querybuf *) alloca (1024); |
492 | |
493 | switch (af) |
494 | { |
495 | case AF_INET: |
496 | sprintf (qbuf, "%u.%u.%u.%u.in-addr.arpa" , (uaddr[3] & 0xff), |
497 | (uaddr[2] & 0xff), (uaddr[1] & 0xff), (uaddr[0] & 0xff)); |
498 | break; |
499 | case AF_INET6: |
500 | qp = qbuf; |
501 | for (n = IN6ADDRSZ - 1; n >= 0; n--) |
502 | { |
503 | static const char nibblechar[16] = "0123456789abcdef" ; |
504 | *qp++ = nibblechar[uaddr[n] & 0xf]; |
505 | *qp++ = '.'; |
506 | *qp++ = nibblechar[(uaddr[n] >> 4) & 0xf]; |
507 | *qp++ = '.'; |
508 | } |
509 | strcpy(qp, "ip6.arpa" ); |
510 | break; |
511 | default: |
512 | /* Cannot happen. */ |
513 | break; |
514 | } |
515 | |
516 | n = __res_context_query (ctx, qbuf, C_IN, T_PTR, host_buffer.buf->buf, |
517 | 1024, &host_buffer.ptr, NULL, NULL, NULL, NULL); |
518 | if (n < 0) |
519 | { |
520 | *h_errnop = h_errno; |
521 | __set_errno (olderr); |
522 | if (host_buffer.buf != orig_host_buffer) |
523 | free (host_buffer.buf); |
524 | __resolv_context_put (ctx); |
525 | return errno == ECONNREFUSED ? NSS_STATUS_UNAVAIL : NSS_STATUS_NOTFOUND; |
526 | } |
527 | |
528 | status = getanswer_r |
529 | (ctx, host_buffer.buf, n, qbuf, T_PTR, result, buffer, buflen, |
530 | errnop, h_errnop, 0 /* XXX */, ttlp, NULL); |
531 | if (host_buffer.buf != orig_host_buffer) |
532 | free (host_buffer.buf); |
533 | if (status != NSS_STATUS_SUCCESS) |
534 | { |
535 | __resolv_context_put (ctx); |
536 | return status; |
537 | } |
538 | |
539 | result->h_addrtype = af; |
540 | result->h_length = len; |
541 | memcpy (host_data->host_addr, addr, len); |
542 | host_data->h_addr_ptrs[0] = (char *) host_data->host_addr; |
543 | host_data->h_addr_ptrs[1] = NULL; |
544 | *h_errnop = NETDB_SUCCESS; |
545 | __resolv_context_put (ctx); |
546 | return NSS_STATUS_SUCCESS; |
547 | } |
548 | hidden_def (_nss_dns_gethostbyaddr2_r) |
549 | |
550 | |
551 | enum nss_status |
552 | _nss_dns_gethostbyaddr_r (const void *addr, socklen_t len, int af, |
553 | struct hostent *result, char *buffer, size_t buflen, |
554 | int *errnop, int *h_errnop) |
555 | { |
556 | return _nss_dns_gethostbyaddr2_r (addr, len, af, result, buffer, buflen, |
557 | errnop, h_errnop, NULL); |
558 | } |
559 | |
560 | static void |
561 | addrsort (struct resolv_context *ctx, char **ap, int num) |
562 | { |
563 | int i, j; |
564 | char **p; |
565 | short aval[MAX_NR_ADDRS]; |
566 | int needsort = 0; |
567 | size_t nsort = __resolv_context_sort_count (ctx); |
568 | |
569 | p = ap; |
570 | if (num > MAX_NR_ADDRS) |
571 | num = MAX_NR_ADDRS; |
572 | for (i = 0; i < num; i++, p++) |
573 | { |
574 | for (j = 0 ; (unsigned)j < nsort; j++) |
575 | { |
576 | struct resolv_sortlist_entry e |
577 | = __resolv_context_sort_entry (ctx, j); |
578 | if (e.addr.s_addr == (((struct in_addr *)(*p))->s_addr & e.mask)) |
579 | break; |
580 | } |
581 | aval[i] = j; |
582 | if (needsort == 0 && i > 0 && j < aval[i-1]) |
583 | needsort = i; |
584 | } |
585 | if (!needsort) |
586 | return; |
587 | |
588 | while (needsort++ < num) |
589 | for (j = needsort - 2; j >= 0; j--) |
590 | if (aval[j] > aval[j+1]) |
591 | { |
592 | char *hp; |
593 | |
594 | i = aval[j]; |
595 | aval[j] = aval[j+1]; |
596 | aval[j+1] = i; |
597 | |
598 | hp = ap[j]; |
599 | ap[j] = ap[j+1]; |
600 | ap[j+1] = hp; |
601 | } |
602 | else |
603 | break; |
604 | } |
605 | |
606 | static enum nss_status |
607 | getanswer_r (struct resolv_context *ctx, |
608 | const querybuf *answer, int anslen, const char *qname, int qtype, |
609 | struct hostent *result, char *buffer, size_t buflen, |
610 | int *errnop, int *h_errnop, int map, int32_t *ttlp, char **canonp) |
611 | { |
612 | struct host_data |
613 | { |
614 | char *aliases[MAX_NR_ALIASES]; |
615 | unsigned char host_addr[16]; /* IPv4 or IPv6 */ |
616 | char *h_addr_ptrs[0]; |
617 | } *host_data; |
618 | int linebuflen; |
619 | const HEADER *hp; |
620 | const u_char *end_of_message, *cp; |
621 | int n, ancount, qdcount; |
622 | int haveanswer, had_error; |
623 | char *bp, **ap, **hap; |
624 | char tbuf[MAXDNAME]; |
625 | const char *tname; |
626 | int (*name_ok) (const char *); |
627 | u_char packtmp[NS_MAXCDNAME]; |
628 | int have_to_map = 0; |
629 | uintptr_t pad = -(uintptr_t) buffer % __alignof__ (struct host_data); |
630 | buffer += pad; |
631 | buflen = buflen > pad ? buflen - pad : 0; |
632 | if (__glibc_unlikely (buflen < sizeof (struct host_data))) |
633 | { |
634 | /* The buffer is too small. */ |
635 | too_small: |
636 | *errnop = ERANGE; |
637 | *h_errnop = NETDB_INTERNAL; |
638 | return NSS_STATUS_TRYAGAIN; |
639 | } |
640 | host_data = (struct host_data *) buffer; |
641 | linebuflen = buflen - sizeof (struct host_data); |
642 | if (buflen - sizeof (struct host_data) != linebuflen) |
643 | linebuflen = INT_MAX; |
644 | |
645 | tname = qname; |
646 | result->h_name = NULL; |
647 | end_of_message = answer->buf + anslen; |
648 | switch (qtype) |
649 | { |
650 | case T_A: |
651 | case T_AAAA: |
652 | name_ok = res_hnok; |
653 | break; |
654 | case T_PTR: |
655 | name_ok = res_dnok; |
656 | break; |
657 | default: |
658 | *errnop = ENOENT; |
659 | return NSS_STATUS_UNAVAIL; /* XXX should be abort(); */ |
660 | } |
661 | |
662 | /* |
663 | * find first satisfactory answer |
664 | */ |
665 | hp = &answer->hdr; |
666 | ancount = ntohs (hp->ancount); |
667 | qdcount = ntohs (hp->qdcount); |
668 | cp = answer->buf + HFIXEDSZ; |
669 | if (__glibc_unlikely (qdcount != 1)) |
670 | { |
671 | *h_errnop = NO_RECOVERY; |
672 | return NSS_STATUS_UNAVAIL; |
673 | } |
674 | if (sizeof (struct host_data) + (ancount + 1) * sizeof (char *) >= buflen) |
675 | goto too_small; |
676 | bp = (char *) &host_data->h_addr_ptrs[ancount + 1]; |
677 | linebuflen -= (ancount + 1) * sizeof (char *); |
678 | |
679 | n = __ns_name_unpack (answer->buf, end_of_message, cp, |
680 | packtmp, sizeof packtmp); |
681 | if (n != -1 && __ns_name_ntop (packtmp, bp, linebuflen) == -1) |
682 | { |
683 | if (__glibc_unlikely (errno == EMSGSIZE)) |
684 | goto too_small; |
685 | |
686 | n = -1; |
687 | } |
688 | |
689 | if (n > 0 && bp[0] == '.') |
690 | bp[0] = '\0'; |
691 | |
692 | if (__glibc_unlikely (n < 0)) |
693 | { |
694 | *errnop = errno; |
695 | *h_errnop = NO_RECOVERY; |
696 | return NSS_STATUS_UNAVAIL; |
697 | } |
698 | if (__glibc_unlikely (name_ok (bp) == 0)) |
699 | { |
700 | errno = EBADMSG; |
701 | *errnop = EBADMSG; |
702 | *h_errnop = NO_RECOVERY; |
703 | return NSS_STATUS_UNAVAIL; |
704 | } |
705 | cp += n + QFIXEDSZ; |
706 | |
707 | if (qtype == T_A || qtype == T_AAAA) |
708 | { |
709 | /* res_send() has already verified that the query name is the |
710 | * same as the one we sent; this just gets the expanded name |
711 | * (i.e., with the succeeding search-domain tacked on). |
712 | */ |
713 | n = strlen (bp) + 1; /* for the \0 */ |
714 | if (n >= MAXHOSTNAMELEN) |
715 | { |
716 | *h_errnop = NO_RECOVERY; |
717 | *errnop = ENOENT; |
718 | return NSS_STATUS_TRYAGAIN; |
719 | } |
720 | result->h_name = bp; |
721 | bp += n; |
722 | linebuflen -= n; |
723 | if (linebuflen < 0) |
724 | goto too_small; |
725 | /* The qname can be abbreviated, but h_name is now absolute. */ |
726 | qname = result->h_name; |
727 | } |
728 | |
729 | ap = host_data->aliases; |
730 | *ap = NULL; |
731 | result->h_aliases = host_data->aliases; |
732 | hap = host_data->h_addr_ptrs; |
733 | *hap = NULL; |
734 | result->h_addr_list = host_data->h_addr_ptrs; |
735 | haveanswer = 0; |
736 | had_error = 0; |
737 | |
738 | while (ancount-- > 0 && cp < end_of_message && had_error == 0) |
739 | { |
740 | int type, class; |
741 | |
742 | n = __ns_name_unpack (answer->buf, end_of_message, cp, |
743 | packtmp, sizeof packtmp); |
744 | if (n != -1 && __ns_name_ntop (packtmp, bp, linebuflen) == -1) |
745 | { |
746 | if (__glibc_unlikely (errno == EMSGSIZE)) |
747 | goto too_small; |
748 | |
749 | n = -1; |
750 | } |
751 | |
752 | if (__glibc_unlikely (n < 0 || (*name_ok) (bp) == 0)) |
753 | { |
754 | ++had_error; |
755 | continue; |
756 | } |
757 | cp += n; /* name */ |
758 | |
759 | if (__glibc_unlikely (cp + 10 > end_of_message)) |
760 | { |
761 | ++had_error; |
762 | continue; |
763 | } |
764 | |
765 | type = __ns_get16 (cp); |
766 | cp += INT16SZ; /* type */ |
767 | class = __ns_get16 (cp); |
768 | cp += INT16SZ; /* class */ |
769 | int32_t ttl = __ns_get32 (cp); |
770 | cp += INT32SZ; /* TTL */ |
771 | n = __ns_get16 (cp); |
772 | cp += INT16SZ; /* len */ |
773 | |
774 | if (end_of_message - cp < n) |
775 | { |
776 | /* RDATA extends beyond the end of the packet. */ |
777 | ++had_error; |
778 | continue; |
779 | } |
780 | |
781 | if (__glibc_unlikely (class != C_IN)) |
782 | { |
783 | /* XXX - debug? syslog? */ |
784 | cp += n; |
785 | continue; /* XXX - had_error++ ? */ |
786 | } |
787 | |
788 | if ((qtype == T_A || qtype == T_AAAA) && type == T_CNAME) |
789 | { |
790 | /* A CNAME could also have a TTL entry. */ |
791 | if (ttlp != NULL && ttl < *ttlp) |
792 | *ttlp = ttl; |
793 | |
794 | if (ap >= &host_data->aliases[MAX_NR_ALIASES - 1]) |
795 | continue; |
796 | n = dn_expand (answer->buf, end_of_message, cp, tbuf, sizeof tbuf); |
797 | if (__glibc_unlikely (n < 0 || (*name_ok) (tbuf) == 0)) |
798 | { |
799 | ++had_error; |
800 | continue; |
801 | } |
802 | cp += n; |
803 | /* Store alias. */ |
804 | *ap++ = bp; |
805 | n = strlen (bp) + 1; /* For the \0. */ |
806 | if (__glibc_unlikely (n >= MAXHOSTNAMELEN)) |
807 | { |
808 | ++had_error; |
809 | continue; |
810 | } |
811 | bp += n; |
812 | linebuflen -= n; |
813 | /* Get canonical name. */ |
814 | n = strlen (tbuf) + 1; /* For the \0. */ |
815 | if (__glibc_unlikely (n > linebuflen)) |
816 | goto too_small; |
817 | if (__glibc_unlikely (n >= MAXHOSTNAMELEN)) |
818 | { |
819 | ++had_error; |
820 | continue; |
821 | } |
822 | result->h_name = bp; |
823 | bp = __mempcpy (bp, tbuf, n); /* Cannot overflow. */ |
824 | linebuflen -= n; |
825 | continue; |
826 | } |
827 | |
828 | if (qtype == T_PTR && type == T_CNAME) |
829 | { |
830 | /* A CNAME could also have a TTL entry. */ |
831 | if (ttlp != NULL && ttl < *ttlp) |
832 | *ttlp = ttl; |
833 | |
834 | n = dn_expand (answer->buf, end_of_message, cp, tbuf, sizeof tbuf); |
835 | if (__glibc_unlikely (n < 0 || res_dnok (tbuf) == 0)) |
836 | { |
837 | ++had_error; |
838 | continue; |
839 | } |
840 | cp += n; |
841 | /* Get canonical name. */ |
842 | n = strlen (tbuf) + 1; /* For the \0. */ |
843 | if (__glibc_unlikely (n > linebuflen)) |
844 | goto too_small; |
845 | if (__glibc_unlikely (n >= MAXHOSTNAMELEN)) |
846 | { |
847 | ++had_error; |
848 | continue; |
849 | } |
850 | tname = bp; |
851 | bp = __mempcpy (bp, tbuf, n); /* Cannot overflow. */ |
852 | linebuflen -= n; |
853 | continue; |
854 | } |
855 | |
856 | if (type == T_A && qtype == T_AAAA && map) |
857 | have_to_map = 1; |
858 | else if (__glibc_unlikely (type != qtype)) |
859 | { |
860 | cp += n; |
861 | continue; /* XXX - had_error++ ? */ |
862 | } |
863 | |
864 | switch (type) |
865 | { |
866 | case T_PTR: |
867 | if (__glibc_unlikely (strcasecmp (tname, bp) != 0)) |
868 | { |
869 | cp += n; |
870 | continue; /* XXX - had_error++ ? */ |
871 | } |
872 | |
873 | n = __ns_name_unpack (answer->buf, end_of_message, cp, |
874 | packtmp, sizeof packtmp); |
875 | if (n != -1 && __ns_name_ntop (packtmp, bp, linebuflen) == -1) |
876 | { |
877 | if (__glibc_unlikely (errno == EMSGSIZE)) |
878 | goto too_small; |
879 | |
880 | n = -1; |
881 | } |
882 | |
883 | if (__glibc_unlikely (n < 0 || res_hnok (bp) == 0)) |
884 | { |
885 | ++had_error; |
886 | break; |
887 | } |
888 | if (ttlp != NULL && ttl < *ttlp) |
889 | *ttlp = ttl; |
890 | /* bind would put multiple PTR records as aliases, but we don't do |
891 | that. */ |
892 | result->h_name = bp; |
893 | *h_errnop = NETDB_SUCCESS; |
894 | return NSS_STATUS_SUCCESS; |
895 | case T_A: |
896 | case T_AAAA: |
897 | if (__glibc_unlikely (strcasecmp (result->h_name, bp) != 0)) |
898 | { |
899 | cp += n; |
900 | continue; /* XXX - had_error++ ? */ |
901 | } |
902 | |
903 | /* Stop parsing at a record whose length is incorrect. */ |
904 | if (n != rrtype_to_rdata_length (type)) |
905 | { |
906 | ++had_error; |
907 | break; |
908 | } |
909 | |
910 | /* Skip records of the wrong type. */ |
911 | if (n != result->h_length) |
912 | { |
913 | cp += n; |
914 | continue; |
915 | } |
916 | if (!haveanswer) |
917 | { |
918 | int nn; |
919 | |
920 | /* We compose a single hostent out of the entire chain of |
921 | entries, so the TTL of the hostent is essentially the lowest |
922 | TTL in the chain. */ |
923 | if (ttlp != NULL && ttl < *ttlp) |
924 | *ttlp = ttl; |
925 | if (canonp != NULL) |
926 | *canonp = bp; |
927 | result->h_name = bp; |
928 | nn = strlen (bp) + 1; /* for the \0 */ |
929 | bp += nn; |
930 | linebuflen -= nn; |
931 | } |
932 | |
933 | linebuflen -= sizeof (align) - ((u_long) bp % sizeof (align)); |
934 | bp += sizeof (align) - ((u_long) bp % sizeof (align)); |
935 | |
936 | if (__glibc_unlikely (n > linebuflen)) |
937 | goto too_small; |
938 | bp = __mempcpy (*hap++ = bp, cp, n); |
939 | cp += n; |
940 | linebuflen -= n; |
941 | break; |
942 | default: |
943 | abort (); |
944 | } |
945 | if (had_error == 0) |
946 | ++haveanswer; |
947 | } |
948 | |
949 | if (haveanswer > 0) |
950 | { |
951 | *ap = NULL; |
952 | *hap = NULL; |
953 | /* |
954 | * Note: we sort even if host can take only one address |
955 | * in its return structures - should give it the "best" |
956 | * address in that case, not some random one |
957 | */ |
958 | if (haveanswer > 1 && qtype == T_A |
959 | && __resolv_context_sort_count (ctx) > 0) |
960 | addrsort (ctx, host_data->h_addr_ptrs, haveanswer); |
961 | |
962 | if (result->h_name == NULL) |
963 | { |
964 | n = strlen (qname) + 1; /* For the \0. */ |
965 | if (n > linebuflen) |
966 | goto too_small; |
967 | if (n >= MAXHOSTNAMELEN) |
968 | goto no_recovery; |
969 | result->h_name = bp; |
970 | bp = __mempcpy (bp, qname, n); /* Cannot overflow. */ |
971 | linebuflen -= n; |
972 | } |
973 | |
974 | if (have_to_map) |
975 | if (map_v4v6_hostent (result, &bp, &linebuflen)) |
976 | goto too_small; |
977 | *h_errnop = NETDB_SUCCESS; |
978 | return NSS_STATUS_SUCCESS; |
979 | } |
980 | no_recovery: |
981 | *h_errnop = NO_RECOVERY; |
982 | *errnop = ENOENT; |
983 | /* Special case here: if the resolver sent a result but it only |
984 | contains a CNAME while we are looking for a T_A or T_AAAA record, |
985 | we fail with NOTFOUND instead of TRYAGAIN. */ |
986 | return ((qtype == T_A || qtype == T_AAAA) && ap != host_data->aliases |
987 | ? NSS_STATUS_NOTFOUND : NSS_STATUS_TRYAGAIN); |
988 | } |
989 | |
990 | |
991 | static enum nss_status |
992 | gaih_getanswer_slice (const querybuf *answer, int anslen, const char *qname, |
993 | struct gaih_addrtuple ***patp, |
994 | char **bufferp, size_t *buflenp, |
995 | int *errnop, int *h_errnop, int32_t *ttlp, int *firstp) |
996 | { |
997 | char *buffer = *bufferp; |
998 | size_t buflen = *buflenp; |
999 | |
1000 | struct gaih_addrtuple **pat = *patp; |
1001 | const HEADER *hp = &answer->hdr; |
1002 | int ancount = ntohs (hp->ancount); |
1003 | int qdcount = ntohs (hp->qdcount); |
1004 | const u_char *cp = answer->buf + HFIXEDSZ; |
1005 | const u_char *end_of_message = answer->buf + anslen; |
1006 | if (__glibc_unlikely (qdcount != 1)) |
1007 | { |
1008 | *h_errnop = NO_RECOVERY; |
1009 | return NSS_STATUS_UNAVAIL; |
1010 | } |
1011 | |
1012 | u_char packtmp[NS_MAXCDNAME]; |
1013 | int n = __ns_name_unpack (answer->buf, end_of_message, cp, |
1014 | packtmp, sizeof packtmp); |
1015 | /* We unpack the name to check it for validity. But we do not need |
1016 | it later. */ |
1017 | if (n != -1 && __ns_name_ntop (packtmp, buffer, buflen) == -1) |
1018 | { |
1019 | if (__glibc_unlikely (errno == EMSGSIZE)) |
1020 | { |
1021 | too_small: |
1022 | *errnop = ERANGE; |
1023 | *h_errnop = NETDB_INTERNAL; |
1024 | return NSS_STATUS_TRYAGAIN; |
1025 | } |
1026 | |
1027 | n = -1; |
1028 | } |
1029 | |
1030 | if (__glibc_unlikely (n < 0)) |
1031 | { |
1032 | *errnop = errno; |
1033 | *h_errnop = NO_RECOVERY; |
1034 | return NSS_STATUS_UNAVAIL; |
1035 | } |
1036 | if (__glibc_unlikely (res_hnok (buffer) == 0)) |
1037 | { |
1038 | errno = EBADMSG; |
1039 | *errnop = EBADMSG; |
1040 | *h_errnop = NO_RECOVERY; |
1041 | return NSS_STATUS_UNAVAIL; |
1042 | } |
1043 | cp += n + QFIXEDSZ; |
1044 | |
1045 | int haveanswer = 0; |
1046 | int had_error = 0; |
1047 | char *canon = NULL; |
1048 | char *h_name = NULL; |
1049 | int h_namelen = 0; |
1050 | |
1051 | if (ancount == 0) |
1052 | { |
1053 | *h_errnop = HOST_NOT_FOUND; |
1054 | return NSS_STATUS_NOTFOUND; |
1055 | } |
1056 | |
1057 | while (ancount-- > 0 && cp < end_of_message && had_error == 0) |
1058 | { |
1059 | n = __ns_name_unpack (answer->buf, end_of_message, cp, |
1060 | packtmp, sizeof packtmp); |
1061 | if (n != -1 && |
1062 | (h_namelen = __ns_name_ntop (packtmp, buffer, buflen)) == -1) |
1063 | { |
1064 | if (__glibc_unlikely (errno == EMSGSIZE)) |
1065 | goto too_small; |
1066 | |
1067 | n = -1; |
1068 | } |
1069 | if (__glibc_unlikely (n < 0 || res_hnok (buffer) == 0)) |
1070 | { |
1071 | ++had_error; |
1072 | continue; |
1073 | } |
1074 | if (*firstp && canon == NULL) |
1075 | { |
1076 | h_name = buffer; |
1077 | buffer += h_namelen; |
1078 | buflen -= h_namelen; |
1079 | } |
1080 | |
1081 | cp += n; /* name */ |
1082 | |
1083 | if (__glibc_unlikely (cp + 10 > end_of_message)) |
1084 | { |
1085 | ++had_error; |
1086 | continue; |
1087 | } |
1088 | |
1089 | int type = __ns_get16 (cp); |
1090 | cp += INT16SZ; /* type */ |
1091 | int class = __ns_get16 (cp); |
1092 | cp += INT16SZ; /* class */ |
1093 | int32_t ttl = __ns_get32 (cp); |
1094 | cp += INT32SZ; /* TTL */ |
1095 | n = __ns_get16 (cp); |
1096 | cp += INT16SZ; /* len */ |
1097 | |
1098 | if (end_of_message - cp < n) |
1099 | { |
1100 | /* RDATA extends beyond the end of the packet. */ |
1101 | ++had_error; |
1102 | continue; |
1103 | } |
1104 | |
1105 | if (class != C_IN) |
1106 | { |
1107 | cp += n; |
1108 | continue; |
1109 | } |
1110 | |
1111 | if (type == T_CNAME) |
1112 | { |
1113 | char tbuf[MAXDNAME]; |
1114 | |
1115 | /* A CNAME could also have a TTL entry. */ |
1116 | if (ttlp != NULL && ttl < *ttlp) |
1117 | *ttlp = ttl; |
1118 | |
1119 | n = dn_expand (answer->buf, end_of_message, cp, tbuf, sizeof tbuf); |
1120 | if (__glibc_unlikely (n < 0 || res_hnok (tbuf) == 0)) |
1121 | { |
1122 | ++had_error; |
1123 | continue; |
1124 | } |
1125 | cp += n; |
1126 | |
1127 | if (*firstp) |
1128 | { |
1129 | /* Reclaim buffer space. */ |
1130 | if (h_name + h_namelen == buffer) |
1131 | { |
1132 | buffer = h_name; |
1133 | buflen += h_namelen; |
1134 | } |
1135 | |
1136 | n = strlen (tbuf) + 1; |
1137 | if (__glibc_unlikely (n > buflen)) |
1138 | goto too_small; |
1139 | if (__glibc_unlikely (n >= MAXHOSTNAMELEN)) |
1140 | { |
1141 | ++had_error; |
1142 | continue; |
1143 | } |
1144 | |
1145 | canon = buffer; |
1146 | buffer = __mempcpy (buffer, tbuf, n); |
1147 | buflen -= n; |
1148 | h_namelen = 0; |
1149 | } |
1150 | continue; |
1151 | } |
1152 | |
1153 | /* Stop parsing if we encounter a record with incorrect RDATA |
1154 | length. */ |
1155 | if (type == T_A || type == T_AAAA) |
1156 | { |
1157 | if (n != rrtype_to_rdata_length (type)) |
1158 | { |
1159 | ++had_error; |
1160 | continue; |
1161 | } |
1162 | } |
1163 | else |
1164 | { |
1165 | /* Skip unknown records. */ |
1166 | cp += n; |
1167 | continue; |
1168 | } |
1169 | |
1170 | assert (type == T_A || type == T_AAAA); |
1171 | if (*pat == NULL) |
1172 | { |
1173 | uintptr_t pad = (-(uintptr_t) buffer |
1174 | % __alignof__ (struct gaih_addrtuple)); |
1175 | buffer += pad; |
1176 | buflen = buflen > pad ? buflen - pad : 0; |
1177 | |
1178 | if (__glibc_unlikely (buflen < sizeof (struct gaih_addrtuple))) |
1179 | goto too_small; |
1180 | |
1181 | *pat = (struct gaih_addrtuple *) buffer; |
1182 | buffer += sizeof (struct gaih_addrtuple); |
1183 | buflen -= sizeof (struct gaih_addrtuple); |
1184 | } |
1185 | |
1186 | (*pat)->name = NULL; |
1187 | (*pat)->next = NULL; |
1188 | |
1189 | if (*firstp) |
1190 | { |
1191 | /* We compose a single hostent out of the entire chain of |
1192 | entries, so the TTL of the hostent is essentially the lowest |
1193 | TTL in the chain. */ |
1194 | if (ttlp != NULL && ttl < *ttlp) |
1195 | *ttlp = ttl; |
1196 | |
1197 | (*pat)->name = canon ?: h_name; |
1198 | |
1199 | *firstp = 0; |
1200 | } |
1201 | |
1202 | (*pat)->family = type == T_A ? AF_INET : AF_INET6; |
1203 | memcpy ((*pat)->addr, cp, n); |
1204 | cp += n; |
1205 | (*pat)->scopeid = 0; |
1206 | |
1207 | pat = &((*pat)->next); |
1208 | |
1209 | haveanswer = 1; |
1210 | } |
1211 | |
1212 | if (haveanswer) |
1213 | { |
1214 | *patp = pat; |
1215 | *bufferp = buffer; |
1216 | *buflenp = buflen; |
1217 | |
1218 | *h_errnop = NETDB_SUCCESS; |
1219 | return NSS_STATUS_SUCCESS; |
1220 | } |
1221 | |
1222 | /* Special case here: if the resolver sent a result but it only |
1223 | contains a CNAME while we are looking for a T_A or T_AAAA record, |
1224 | we fail with NOTFOUND instead of TRYAGAIN. */ |
1225 | if (canon != NULL) |
1226 | { |
1227 | *h_errnop = HOST_NOT_FOUND; |
1228 | return NSS_STATUS_NOTFOUND; |
1229 | } |
1230 | |
1231 | *h_errnop = NETDB_INTERNAL; |
1232 | return NSS_STATUS_TRYAGAIN; |
1233 | } |
1234 | |
1235 | |
1236 | static enum nss_status |
1237 | gaih_getanswer (const querybuf *answer1, int anslen1, const querybuf *answer2, |
1238 | int anslen2, const char *qname, |
1239 | struct gaih_addrtuple **pat, char *buffer, size_t buflen, |
1240 | int *errnop, int *h_errnop, int32_t *ttlp) |
1241 | { |
1242 | int first = 1; |
1243 | |
1244 | enum nss_status status = NSS_STATUS_NOTFOUND; |
1245 | |
1246 | /* Combining the NSS status of two distinct queries requires some |
1247 | compromise and attention to symmetry (A or AAAA queries can be |
1248 | returned in any order). What follows is a breakdown of how this |
1249 | code is expected to work and why. We discuss only SUCCESS, |
1250 | TRYAGAIN, NOTFOUND and UNAVAIL, since they are the only returns |
1251 | that apply (though RETURN and MERGE exist). We make a distinction |
1252 | between TRYAGAIN (recoverable) and TRYAGAIN' (not-recoverable). |
1253 | A recoverable TRYAGAIN is almost always due to buffer size issues |
1254 | and returns ERANGE in errno and the caller is expected to retry |
1255 | with a larger buffer. |
1256 | |
1257 | Lastly, you may be tempted to make significant changes to the |
1258 | conditions in this code to bring about symmetry between responses. |
1259 | Please don't change anything without due consideration for |
1260 | expected application behaviour. Some of the synthesized responses |
1261 | aren't very well thought out and sometimes appear to imply that |
1262 | IPv4 responses are always answer 1, and IPv6 responses are always |
1263 | answer 2, but that's not true (see the implementation of send_dg |
1264 | and send_vc to see response can arrive in any order, particularly |
1265 | for UDP). However, we expect it holds roughly enough of the time |
1266 | that this code works, but certainly needs to be fixed to make this |
1267 | a more robust implementation. |
1268 | |
1269 | ---------------------------------------------- |
1270 | | Answer 1 Status / | Synthesized | Reason | |
1271 | | Answer 2 Status | Status | | |
1272 | |--------------------------------------------| |
1273 | | SUCCESS/SUCCESS | SUCCESS | [1] | |
1274 | | SUCCESS/TRYAGAIN | TRYAGAIN | [5] | |
1275 | | SUCCESS/TRYAGAIN' | SUCCESS | [1] | |
1276 | | SUCCESS/NOTFOUND | SUCCESS | [1] | |
1277 | | SUCCESS/UNAVAIL | SUCCESS | [1] | |
1278 | | TRYAGAIN/SUCCESS | TRYAGAIN | [2] | |
1279 | | TRYAGAIN/TRYAGAIN | TRYAGAIN | [2] | |
1280 | | TRYAGAIN/TRYAGAIN' | TRYAGAIN | [2] | |
1281 | | TRYAGAIN/NOTFOUND | TRYAGAIN | [2] | |
1282 | | TRYAGAIN/UNAVAIL | TRYAGAIN | [2] | |
1283 | | TRYAGAIN'/SUCCESS | SUCCESS | [3] | |
1284 | | TRYAGAIN'/TRYAGAIN | TRYAGAIN | [3] | |
1285 | | TRYAGAIN'/TRYAGAIN' | TRYAGAIN' | [3] | |
1286 | | TRYAGAIN'/NOTFOUND | TRYAGAIN' | [3] | |
1287 | | TRYAGAIN'/UNAVAIL | UNAVAIL | [3] | |
1288 | | NOTFOUND/SUCCESS | SUCCESS | [3] | |
1289 | | NOTFOUND/TRYAGAIN | TRYAGAIN | [3] | |
1290 | | NOTFOUND/TRYAGAIN' | TRYAGAIN' | [3] | |
1291 | | NOTFOUND/NOTFOUND | NOTFOUND | [3] | |
1292 | | NOTFOUND/UNAVAIL | UNAVAIL | [3] | |
1293 | | UNAVAIL/SUCCESS | UNAVAIL | [4] | |
1294 | | UNAVAIL/TRYAGAIN | UNAVAIL | [4] | |
1295 | | UNAVAIL/TRYAGAIN' | UNAVAIL | [4] | |
1296 | | UNAVAIL/NOTFOUND | UNAVAIL | [4] | |
1297 | | UNAVAIL/UNAVAIL | UNAVAIL | [4] | |
1298 | ---------------------------------------------- |
1299 | |
1300 | [1] If the first response is a success we return success. |
1301 | This ignores the state of the second answer and in fact |
1302 | incorrectly sets errno and h_errno to that of the second |
1303 | answer. However because the response is a success we ignore |
1304 | *errnop and *h_errnop (though that means you touched errno on |
1305 | success). We are being conservative here and returning the |
1306 | likely IPv4 response in the first answer as a success. |
1307 | |
1308 | [2] If the first response is a recoverable TRYAGAIN we return |
1309 | that instead of looking at the second response. The |
1310 | expectation here is that we have failed to get an IPv4 response |
1311 | and should retry both queries. |
1312 | |
1313 | [3] If the first response was not a SUCCESS and the second |
1314 | response is not NOTFOUND (had a SUCCESS, need to TRYAGAIN, |
1315 | or failed entirely e.g. TRYAGAIN' and UNAVAIL) then use the |
1316 | result from the second response, otherwise the first responses |
1317 | status is used. Again we have some odd side-effects when the |
1318 | second response is NOTFOUND because we overwrite *errnop and |
1319 | *h_errnop that means that a first answer of NOTFOUND might see |
1320 | its *errnop and *h_errnop values altered. Whether it matters |
1321 | in practice that a first response NOTFOUND has the wrong |
1322 | *errnop and *h_errnop is undecided. |
1323 | |
1324 | [4] If the first response is UNAVAIL we return that instead of |
1325 | looking at the second response. The expectation here is that |
1326 | it will have failed similarly e.g. configuration failure. |
1327 | |
1328 | [5] Testing this code is complicated by the fact that truncated |
1329 | second response buffers might be returned as SUCCESS if the |
1330 | first answer is a SUCCESS. To fix this we add symmetry to |
1331 | TRYAGAIN with the second response. If the second response |
1332 | is a recoverable error we now return TRYAGIN even if the first |
1333 | response was SUCCESS. */ |
1334 | |
1335 | if (anslen1 > 0) |
1336 | status = gaih_getanswer_slice(answer1, anslen1, qname, |
1337 | &pat, &buffer, &buflen, |
1338 | errnop, h_errnop, ttlp, |
1339 | &first); |
1340 | |
1341 | if ((status == NSS_STATUS_SUCCESS || status == NSS_STATUS_NOTFOUND |
1342 | || (status == NSS_STATUS_TRYAGAIN |
1343 | /* We want to look at the second answer in case of an |
1344 | NSS_STATUS_TRYAGAIN only if the error is non-recoverable, i.e. |
1345 | *h_errnop is NO_RECOVERY. If not, and if the failure was due to |
1346 | an insufficient buffer (ERANGE), then we need to drop the results |
1347 | and pass on the NSS_STATUS_TRYAGAIN to the caller so that it can |
1348 | repeat the query with a larger buffer. */ |
1349 | && (*errnop != ERANGE || *h_errnop == NO_RECOVERY))) |
1350 | && answer2 != NULL && anslen2 > 0) |
1351 | { |
1352 | enum nss_status status2 = gaih_getanswer_slice(answer2, anslen2, qname, |
1353 | &pat, &buffer, &buflen, |
1354 | errnop, h_errnop, ttlp, |
1355 | &first); |
1356 | /* Use the second response status in some cases. */ |
1357 | if (status != NSS_STATUS_SUCCESS && status2 != NSS_STATUS_NOTFOUND) |
1358 | status = status2; |
1359 | /* Do not return a truncated second response (unless it was |
1360 | unavoidable e.g. unrecoverable TRYAGAIN). */ |
1361 | if (status == NSS_STATUS_SUCCESS |
1362 | && (status2 == NSS_STATUS_TRYAGAIN |
1363 | && *errnop == ERANGE && *h_errnop != NO_RECOVERY)) |
1364 | status = NSS_STATUS_TRYAGAIN; |
1365 | } |
1366 | |
1367 | return status; |
1368 | } |
1369 | |