1 | /* |
2 | * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC") |
3 | * Copyright (c) 1996,1999 by Internet Software Consortium. |
4 | * |
5 | * Permission to use, copy, modify, and distribute this software for any |
6 | * purpose with or without fee is hereby granted, provided that the above |
7 | * copyright notice and this permission notice appear in all copies. |
8 | * |
9 | * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES |
10 | * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF |
11 | * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR |
12 | * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
13 | * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN |
14 | * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT |
15 | * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
16 | */ |
17 | |
18 | #if !defined(_LIBC) && !defined(lint) |
19 | static const char rcsid[] = "$BINDId: ns_name.c,v 8.15 2000/03/30 22:53:46 vixie Exp $" ; |
20 | #endif |
21 | |
22 | #include <sys/types.h> |
23 | |
24 | #include <netinet/in.h> |
25 | #include <arpa/nameser.h> |
26 | |
27 | #include <errno.h> |
28 | #include <resolv.h> |
29 | #include <string.h> |
30 | #include <ctype.h> |
31 | #include <stdlib.h> |
32 | #include <limits.h> |
33 | |
34 | # define SPRINTF(x) ((size_t)sprintf x) |
35 | |
36 | #define NS_TYPE_ELT 0x40 /*%< EDNS0 extended label type */ |
37 | #define DNS_LABELTYPE_BITSTRING 0x41 |
38 | |
39 | /* Data. */ |
40 | |
41 | static const char digits[] = "0123456789" ; |
42 | |
43 | static const char digitvalue[256] = { |
44 | -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*16*/ |
45 | -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*32*/ |
46 | -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*48*/ |
47 | 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -1, -1, -1, -1, -1, -1, /*64*/ |
48 | -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*80*/ |
49 | -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*96*/ |
50 | -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*112*/ |
51 | -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*128*/ |
52 | -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, |
53 | -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, |
54 | -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, |
55 | -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, |
56 | -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, |
57 | -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, |
58 | -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, |
59 | -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*256*/ |
60 | }; |
61 | |
62 | /* Forward. */ |
63 | |
64 | static int special(int); |
65 | static int printable(int); |
66 | static int dn_find(const u_char *, const u_char *, |
67 | const u_char * const *, |
68 | const u_char * const *); |
69 | static int encode_bitstring(const char **, const char *, |
70 | unsigned char **, unsigned char **, |
71 | unsigned const char *); |
72 | static int labellen(const u_char *); |
73 | static int decode_bitstring(const unsigned char **, |
74 | char *, const char *); |
75 | |
76 | /* Public. */ |
77 | |
78 | /*% |
79 | * Convert an encoded domain name to printable ascii as per RFC1035. |
80 | |
81 | * return: |
82 | *\li Number of bytes written to buffer, or -1 (with errno set) |
83 | * |
84 | * notes: |
85 | *\li The root is returned as "." |
86 | *\li All other domains are returned in non absolute form |
87 | */ |
88 | int |
89 | ns_name_ntop(const u_char *src, char *dst, size_t dstsiz) |
90 | { |
91 | const u_char *cp; |
92 | char *dn, *eom; |
93 | u_char c; |
94 | u_int n; |
95 | int l; |
96 | |
97 | cp = src; |
98 | dn = dst; |
99 | eom = dst + dstsiz; |
100 | |
101 | while ((n = *cp++) != 0) { |
102 | if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) { |
103 | /* Some kind of compression pointer. */ |
104 | __set_errno (EMSGSIZE); |
105 | return (-1); |
106 | } |
107 | if (dn != dst) { |
108 | if (dn >= eom) { |
109 | __set_errno (EMSGSIZE); |
110 | return (-1); |
111 | } |
112 | *dn++ = '.'; |
113 | } |
114 | if ((l = labellen(cp - 1)) < 0) { |
115 | __set_errno (EMSGSIZE); |
116 | return(-1); |
117 | } |
118 | if (dn + l >= eom) { |
119 | __set_errno (EMSGSIZE); |
120 | return (-1); |
121 | } |
122 | if ((n & NS_CMPRSFLGS) == NS_TYPE_ELT) { |
123 | int m; |
124 | |
125 | if (n != DNS_LABELTYPE_BITSTRING) { |
126 | /* XXX: labellen should reject this case */ |
127 | __set_errno (EINVAL); |
128 | return(-1); |
129 | } |
130 | if ((m = decode_bitstring(&cp, dn, eom)) < 0) |
131 | { |
132 | __set_errno (EMSGSIZE); |
133 | return(-1); |
134 | } |
135 | dn += m; |
136 | continue; |
137 | } |
138 | for ((void)NULL; l > 0; l--) { |
139 | c = *cp++; |
140 | if (special(c)) { |
141 | if (dn + 1 >= eom) { |
142 | __set_errno (EMSGSIZE); |
143 | return (-1); |
144 | } |
145 | *dn++ = '\\'; |
146 | *dn++ = (char)c; |
147 | } else if (!printable(c)) { |
148 | if (dn + 3 >= eom) { |
149 | __set_errno (EMSGSIZE); |
150 | return (-1); |
151 | } |
152 | *dn++ = '\\'; |
153 | *dn++ = digits[c / 100]; |
154 | *dn++ = digits[(c % 100) / 10]; |
155 | *dn++ = digits[c % 10]; |
156 | } else { |
157 | if (dn >= eom) { |
158 | __set_errno (EMSGSIZE); |
159 | return (-1); |
160 | } |
161 | *dn++ = (char)c; |
162 | } |
163 | } |
164 | } |
165 | if (dn == dst) { |
166 | if (dn >= eom) { |
167 | __set_errno (EMSGSIZE); |
168 | return (-1); |
169 | } |
170 | *dn++ = '.'; |
171 | } |
172 | if (dn >= eom) { |
173 | __set_errno (EMSGSIZE); |
174 | return (-1); |
175 | } |
176 | *dn++ = '\0'; |
177 | return (dn - dst); |
178 | } |
179 | libresolv_hidden_def (ns_name_ntop) |
180 | strong_alias (ns_name_ntop, __ns_name_ntop) |
181 | |
182 | /*% |
183 | * Convert an ascii string into an encoded domain name as per RFC1035. |
184 | * |
185 | * return: |
186 | * |
187 | *\li -1 if it fails |
188 | *\li 1 if string was fully qualified |
189 | *\li 0 is string was not fully qualified |
190 | * |
191 | * notes: |
192 | *\li Enforces label and domain length limits. |
193 | */ |
194 | |
195 | int |
196 | ns_name_pton(const char *src, u_char *dst, size_t dstsiz) |
197 | { |
198 | u_char *label, *bp, *eom; |
199 | int c, n, escaped, e = 0; |
200 | char *cp; |
201 | |
202 | escaped = 0; |
203 | bp = dst; |
204 | eom = dst + dstsiz; |
205 | label = bp++; |
206 | |
207 | while ((c = *src++) != 0) { |
208 | if (escaped) { |
209 | if (c == '[') { /*%< start a bit string label */ |
210 | if ((cp = strchr(src, ']')) == NULL) { |
211 | __set_errno (EINVAL); |
212 | return(-1); |
213 | } |
214 | if ((e = encode_bitstring(&src, cp + 2, |
215 | &label, &bp, eom)) |
216 | != 0) { |
217 | __set_errno (e); |
218 | return(-1); |
219 | } |
220 | escaped = 0; |
221 | label = bp++; |
222 | if ((c = *src++) == 0) |
223 | goto done; |
224 | else if (c != '.') { |
225 | __set_errno (EINVAL); |
226 | return(-1); |
227 | } |
228 | continue; |
229 | } |
230 | else if ((cp = strchr(digits, c)) != NULL) { |
231 | n = (cp - digits) * 100; |
232 | if ((c = *src++) == 0 || |
233 | (cp = strchr(digits, c)) == NULL) { |
234 | __set_errno (EMSGSIZE); |
235 | return (-1); |
236 | } |
237 | n += (cp - digits) * 10; |
238 | if ((c = *src++) == 0 || |
239 | (cp = strchr(digits, c)) == NULL) { |
240 | __set_errno (EMSGSIZE); |
241 | return (-1); |
242 | } |
243 | n += (cp - digits); |
244 | if (n > 255) { |
245 | __set_errno (EMSGSIZE); |
246 | return (-1); |
247 | } |
248 | c = n; |
249 | } |
250 | escaped = 0; |
251 | } else if (c == '\\') { |
252 | escaped = 1; |
253 | continue; |
254 | } else if (c == '.') { |
255 | c = (bp - label - 1); |
256 | if ((c & NS_CMPRSFLGS) != 0) { /*%< Label too big. */ |
257 | __set_errno (EMSGSIZE); |
258 | return (-1); |
259 | } |
260 | if (label >= eom) { |
261 | __set_errno (EMSGSIZE); |
262 | return (-1); |
263 | } |
264 | *label = c; |
265 | /* Fully qualified ? */ |
266 | if (*src == '\0') { |
267 | if (c != 0) { |
268 | if (bp >= eom) { |
269 | __set_errno (EMSGSIZE); |
270 | return (-1); |
271 | } |
272 | *bp++ = '\0'; |
273 | } |
274 | if ((bp - dst) > MAXCDNAME) { |
275 | __set_errno (EMSGSIZE); |
276 | return (-1); |
277 | } |
278 | return (1); |
279 | } |
280 | if (c == 0 || *src == '.') { |
281 | __set_errno (EMSGSIZE); |
282 | return (-1); |
283 | } |
284 | label = bp++; |
285 | continue; |
286 | } |
287 | if (bp >= eom) { |
288 | __set_errno (EMSGSIZE); |
289 | return (-1); |
290 | } |
291 | *bp++ = (u_char)c; |
292 | } |
293 | c = (bp - label - 1); |
294 | if ((c & NS_CMPRSFLGS) != 0) { /*%< Label too big. */ |
295 | __set_errno (EMSGSIZE); |
296 | return (-1); |
297 | } |
298 | done: |
299 | if (label >= eom) { |
300 | __set_errno (EMSGSIZE); |
301 | return (-1); |
302 | } |
303 | *label = c; |
304 | if (c != 0) { |
305 | if (bp >= eom) { |
306 | __set_errno (EMSGSIZE); |
307 | return (-1); |
308 | } |
309 | *bp++ = 0; |
310 | } |
311 | if ((bp - dst) > MAXCDNAME) { /*%< src too big */ |
312 | __set_errno (EMSGSIZE); |
313 | return (-1); |
314 | } |
315 | return (0); |
316 | } |
317 | libresolv_hidden_def (ns_name_pton) |
318 | |
319 | /*% |
320 | * Convert a network strings labels into all lowercase. |
321 | * |
322 | * return: |
323 | *\li Number of bytes written to buffer, or -1 (with errno set) |
324 | * |
325 | * notes: |
326 | *\li Enforces label and domain length limits. |
327 | */ |
328 | |
329 | int |
330 | ns_name_ntol(const u_char *src, u_char *dst, size_t dstsiz) |
331 | { |
332 | const u_char *cp; |
333 | u_char *dn, *eom; |
334 | u_char c; |
335 | u_int n; |
336 | int l; |
337 | |
338 | cp = src; |
339 | dn = dst; |
340 | eom = dst + dstsiz; |
341 | |
342 | if (dn >= eom) { |
343 | __set_errno (EMSGSIZE); |
344 | return (-1); |
345 | } |
346 | while ((n = *cp++) != 0) { |
347 | if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) { |
348 | /* Some kind of compression pointer. */ |
349 | __set_errno (EMSGSIZE); |
350 | return (-1); |
351 | } |
352 | *dn++ = n; |
353 | if ((l = labellen(cp - 1)) < 0) { |
354 | __set_errno (EMSGSIZE); |
355 | return (-1); |
356 | } |
357 | if (dn + l >= eom) { |
358 | __set_errno (EMSGSIZE); |
359 | return (-1); |
360 | } |
361 | for ((void)NULL; l > 0; l--) { |
362 | c = *cp++; |
363 | if (isupper(c)) |
364 | *dn++ = tolower(c); |
365 | else |
366 | *dn++ = c; |
367 | } |
368 | } |
369 | *dn++ = '\0'; |
370 | return (dn - dst); |
371 | } |
372 | |
373 | /*% |
374 | * Unpack a domain name from a message, source may be compressed. |
375 | * |
376 | * return: |
377 | *\li -1 if it fails, or consumed octets if it succeeds. |
378 | */ |
379 | int |
380 | ns_name_unpack(const u_char *msg, const u_char *eom, const u_char *src, |
381 | u_char *dst, size_t dstsiz) |
382 | { |
383 | const u_char *srcp, *dstlim; |
384 | u_char *dstp; |
385 | int n, len, checked, l; |
386 | |
387 | len = -1; |
388 | checked = 0; |
389 | dstp = dst; |
390 | srcp = src; |
391 | dstlim = dst + dstsiz; |
392 | if (srcp < msg || srcp >= eom) { |
393 | __set_errno (EMSGSIZE); |
394 | return (-1); |
395 | } |
396 | /* Fetch next label in domain name. */ |
397 | while ((n = *srcp++) != 0) { |
398 | /* Check for indirection. */ |
399 | switch (n & NS_CMPRSFLGS) { |
400 | case 0: |
401 | case NS_TYPE_ELT: |
402 | /* Limit checks. */ |
403 | if ((l = labellen(srcp - 1)) < 0) { |
404 | __set_errno (EMSGSIZE); |
405 | return(-1); |
406 | } |
407 | if (dstp + l + 1 >= dstlim || srcp + l >= eom) { |
408 | __set_errno (EMSGSIZE); |
409 | return (-1); |
410 | } |
411 | checked += l + 1; |
412 | *dstp++ = n; |
413 | memcpy(dstp, srcp, l); |
414 | dstp += l; |
415 | srcp += l; |
416 | break; |
417 | |
418 | case NS_CMPRSFLGS: |
419 | if (srcp >= eom) { |
420 | __set_errno (EMSGSIZE); |
421 | return (-1); |
422 | } |
423 | if (len < 0) |
424 | len = srcp - src + 1; |
425 | srcp = msg + (((n & 0x3f) << 8) | (*srcp & 0xff)); |
426 | if (srcp < msg || srcp >= eom) { /*%< Out of range. */ |
427 | __set_errno (EMSGSIZE); |
428 | return (-1); |
429 | } |
430 | checked += 2; |
431 | /* |
432 | * Check for loops in the compressed name; |
433 | * if we've looked at the whole message, |
434 | * there must be a loop. |
435 | */ |
436 | if (checked >= eom - msg) { |
437 | __set_errno (EMSGSIZE); |
438 | return (-1); |
439 | } |
440 | break; |
441 | |
442 | default: |
443 | __set_errno (EMSGSIZE); |
444 | return (-1); /*%< flag error */ |
445 | } |
446 | } |
447 | *dstp = '\0'; |
448 | if (len < 0) |
449 | len = srcp - src; |
450 | return (len); |
451 | } |
452 | libresolv_hidden_def (ns_name_unpack) |
453 | strong_alias (ns_name_unpack, __ns_name_unpack) |
454 | |
455 | /*% |
456 | * Pack domain name 'domain' into 'comp_dn'. |
457 | * |
458 | * return: |
459 | *\li Size of the compressed name, or -1. |
460 | * |
461 | * notes: |
462 | *\li 'dnptrs' is an array of pointers to previous compressed names. |
463 | *\li dnptrs[0] is a pointer to the beginning of the message. The array |
464 | * ends with NULL. |
465 | *\li 'lastdnptr' is a pointer to the end of the array pointed to |
466 | * by 'dnptrs'. |
467 | * |
468 | * Side effects: |
469 | *\li The list of pointers in dnptrs is updated for labels inserted into |
470 | * the message as we compress the name. If 'dnptr' is NULL, we don't |
471 | * try to compress names. If 'lastdnptr' is NULL, we don't update the |
472 | * list. |
473 | */ |
474 | int |
475 | ns_name_pack(const u_char *src, u_char *dst, int dstsiz, |
476 | const u_char **dnptrs, const u_char **lastdnptr) |
477 | { |
478 | u_char *dstp; |
479 | const u_char **cpp, **lpp, *eob, *msg; |
480 | const u_char *srcp; |
481 | int n, l, first = 1; |
482 | |
483 | srcp = src; |
484 | dstp = dst; |
485 | eob = dstp + dstsiz; |
486 | lpp = cpp = NULL; |
487 | if (dnptrs != NULL) { |
488 | if ((msg = *dnptrs++) != NULL) { |
489 | for (cpp = dnptrs; *cpp != NULL; cpp++) |
490 | (void)NULL; |
491 | lpp = cpp; /*%< end of list to search */ |
492 | } |
493 | } else |
494 | msg = NULL; |
495 | |
496 | /* make sure the domain we are about to add is legal */ |
497 | l = 0; |
498 | do { |
499 | int l0; |
500 | |
501 | n = *srcp; |
502 | if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) { |
503 | __set_errno (EMSGSIZE); |
504 | return (-1); |
505 | } |
506 | if ((l0 = labellen(srcp)) < 0) { |
507 | __set_errno (EINVAL); |
508 | return(-1); |
509 | } |
510 | l += l0 + 1; |
511 | if (l > MAXCDNAME) { |
512 | __set_errno (EMSGSIZE); |
513 | return (-1); |
514 | } |
515 | srcp += l0 + 1; |
516 | } while (n != 0); |
517 | |
518 | /* from here on we need to reset compression pointer array on error */ |
519 | srcp = src; |
520 | do { |
521 | /* Look to see if we can use pointers. */ |
522 | n = *srcp; |
523 | if (n != 0 && msg != NULL) { |
524 | l = dn_find(srcp, msg, (const u_char * const *)dnptrs, |
525 | (const u_char * const *)lpp); |
526 | if (l >= 0) { |
527 | if (dstp + 1 >= eob) { |
528 | goto cleanup; |
529 | } |
530 | *dstp++ = (l >> 8) | NS_CMPRSFLGS; |
531 | *dstp++ = l % 256; |
532 | return (dstp - dst); |
533 | } |
534 | /* Not found, save it. */ |
535 | if (lastdnptr != NULL && cpp < lastdnptr - 1 && |
536 | (dstp - msg) < 0x4000 && first) { |
537 | *cpp++ = dstp; |
538 | *cpp = NULL; |
539 | first = 0; |
540 | } |
541 | } |
542 | /* copy label to buffer */ |
543 | if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) { |
544 | /* Should not happen. */ |
545 | goto cleanup; |
546 | } |
547 | n = labellen(srcp); |
548 | if (dstp + 1 + n >= eob) { |
549 | goto cleanup; |
550 | } |
551 | memcpy(dstp, srcp, n + 1); |
552 | srcp += n + 1; |
553 | dstp += n + 1; |
554 | } while (n != 0); |
555 | |
556 | if (dstp > eob) { |
557 | cleanup: |
558 | if (msg != NULL) |
559 | *lpp = NULL; |
560 | __set_errno (EMSGSIZE); |
561 | return (-1); |
562 | } |
563 | return (dstp - dst); |
564 | } |
565 | libresolv_hidden_def (ns_name_pack) |
566 | |
567 | /*% |
568 | * Expand compressed domain name to presentation format. |
569 | * |
570 | * return: |
571 | *\li Number of bytes read out of `src', or -1 (with errno set). |
572 | * |
573 | * note: |
574 | *\li Root domain returns as "." not "". |
575 | */ |
576 | int |
577 | ns_name_uncompress(const u_char *msg, const u_char *eom, const u_char *src, |
578 | char *dst, size_t dstsiz) |
579 | { |
580 | u_char tmp[NS_MAXCDNAME]; |
581 | int n; |
582 | |
583 | if ((n = ns_name_unpack(msg, eom, src, tmp, sizeof tmp)) == -1) |
584 | return (-1); |
585 | if (ns_name_ntop(tmp, dst, dstsiz) == -1) |
586 | return (-1); |
587 | return (n); |
588 | } |
589 | libresolv_hidden_def (ns_name_uncompress) |
590 | |
591 | /*% |
592 | * Compress a domain name into wire format, using compression pointers. |
593 | * |
594 | * return: |
595 | *\li Number of bytes consumed in `dst' or -1 (with errno set). |
596 | * |
597 | * notes: |
598 | *\li 'dnptrs' is an array of pointers to previous compressed names. |
599 | *\li dnptrs[0] is a pointer to the beginning of the message. |
600 | *\li The list ends with NULL. 'lastdnptr' is a pointer to the end of the |
601 | * array pointed to by 'dnptrs'. Side effect is to update the list of |
602 | * pointers for labels inserted into the message as we compress the name. |
603 | *\li If 'dnptr' is NULL, we don't try to compress names. If 'lastdnptr' |
604 | * is NULL, we don't update the list. |
605 | */ |
606 | int |
607 | ns_name_compress(const char *src, u_char *dst, size_t dstsiz, |
608 | const u_char **dnptrs, const u_char **lastdnptr) |
609 | { |
610 | u_char tmp[NS_MAXCDNAME]; |
611 | |
612 | if (ns_name_pton(src, tmp, sizeof tmp) == -1) |
613 | return (-1); |
614 | return (ns_name_pack(tmp, dst, dstsiz, dnptrs, lastdnptr)); |
615 | } |
616 | libresolv_hidden_def (ns_name_compress) |
617 | |
618 | /*% |
619 | * Reset dnptrs so that there are no active references to pointers at or |
620 | * after src. |
621 | */ |
622 | void |
623 | ns_name_rollback(const u_char *src, const u_char **dnptrs, |
624 | const u_char **lastdnptr) |
625 | { |
626 | while (dnptrs < lastdnptr && *dnptrs != NULL) { |
627 | if (*dnptrs >= src) { |
628 | *dnptrs = NULL; |
629 | break; |
630 | } |
631 | dnptrs++; |
632 | } |
633 | } |
634 | |
635 | /*% |
636 | * Advance *ptrptr to skip over the compressed name it points at. |
637 | * |
638 | * return: |
639 | *\li 0 on success, -1 (with errno set) on failure. |
640 | */ |
641 | int |
642 | ns_name_skip(const u_char **ptrptr, const u_char *eom) |
643 | { |
644 | const u_char *cp; |
645 | u_int n; |
646 | int l; |
647 | |
648 | cp = *ptrptr; |
649 | while (cp < eom && (n = *cp++) != 0) { |
650 | /* Check for indirection. */ |
651 | switch (n & NS_CMPRSFLGS) { |
652 | case 0: /*%< normal case, n == len */ |
653 | cp += n; |
654 | continue; |
655 | case NS_TYPE_ELT: /*%< EDNS0 extended label */ |
656 | if ((l = labellen(cp - 1)) < 0) { |
657 | __set_errno (EMSGSIZE); |
658 | return(-1); |
659 | } |
660 | cp += l; |
661 | continue; |
662 | case NS_CMPRSFLGS: /*%< indirection */ |
663 | cp++; |
664 | break; |
665 | default: /*%< illegal type */ |
666 | __set_errno (EMSGSIZE); |
667 | return (-1); |
668 | } |
669 | break; |
670 | } |
671 | if (cp > eom) { |
672 | __set_errno (EMSGSIZE); |
673 | return (-1); |
674 | } |
675 | *ptrptr = cp; |
676 | return (0); |
677 | } |
678 | libresolv_hidden_def (ns_name_skip) |
679 | |
680 | /* Private. */ |
681 | |
682 | /*% |
683 | * Thinking in noninternationalized USASCII (per the DNS spec), |
684 | * is this character special ("in need of quoting") ? |
685 | * |
686 | * return: |
687 | *\li boolean. |
688 | */ |
689 | static int |
690 | special(int ch) { |
691 | switch (ch) { |
692 | case 0x22: /*%< '"' */ |
693 | case 0x2E: /*%< '.' */ |
694 | case 0x3B: /*%< ';' */ |
695 | case 0x5C: /*%< '\\' */ |
696 | case 0x28: /*%< '(' */ |
697 | case 0x29: /*%< ')' */ |
698 | /* Special modifiers in zone files. */ |
699 | case 0x40: /*%< '@' */ |
700 | case 0x24: /*%< '$' */ |
701 | return (1); |
702 | default: |
703 | return (0); |
704 | } |
705 | } |
706 | |
707 | /*% |
708 | * Thinking in noninternationalized USASCII (per the DNS spec), |
709 | * is this character visible and not a space when printed ? |
710 | * |
711 | * return: |
712 | *\li boolean. |
713 | */ |
714 | static int |
715 | printable(int ch) { |
716 | return (ch > 0x20 && ch < 0x7f); |
717 | } |
718 | |
719 | /*% |
720 | * Thinking in noninternationalized USASCII (per the DNS spec), |
721 | * convert this character to lower case if it's upper case. |
722 | */ |
723 | static int |
724 | mklower(int ch) { |
725 | if (ch >= 0x41 && ch <= 0x5A) |
726 | return (ch + 0x20); |
727 | return (ch); |
728 | } |
729 | |
730 | /*% |
731 | * Search for the counted-label name in an array of compressed names. |
732 | * |
733 | * return: |
734 | *\li offset from msg if found, or -1. |
735 | * |
736 | * notes: |
737 | *\li dnptrs is the pointer to the first name on the list, |
738 | *\li not the pointer to the start of the message. |
739 | */ |
740 | static int |
741 | dn_find(const u_char *domain, const u_char *msg, |
742 | const u_char * const *dnptrs, |
743 | const u_char * const *lastdnptr) |
744 | { |
745 | const u_char *dn, *cp, *sp; |
746 | const u_char * const *cpp; |
747 | u_int n; |
748 | |
749 | for (cpp = dnptrs; cpp < lastdnptr; cpp++) { |
750 | sp = *cpp; |
751 | /* |
752 | * terminate search on: |
753 | * root label |
754 | * compression pointer |
755 | * unusable offset |
756 | */ |
757 | while (*sp != 0 && (*sp & NS_CMPRSFLGS) == 0 && |
758 | (sp - msg) < 0x4000) { |
759 | dn = domain; |
760 | cp = sp; |
761 | while ((n = *cp++) != 0) { |
762 | /* |
763 | * check for indirection |
764 | */ |
765 | switch (n & NS_CMPRSFLGS) { |
766 | case 0: /*%< normal case, n == len */ |
767 | n = labellen(cp - 1); /*%< XXX */ |
768 | if (n != *dn++) |
769 | goto next; |
770 | |
771 | for ((void)NULL; n > 0; n--) |
772 | if (mklower(*dn++) != |
773 | mklower(*cp++)) |
774 | goto next; |
775 | /* Is next root for both ? */ |
776 | if (*dn == '\0' && *cp == '\0') |
777 | return (sp - msg); |
778 | if (*dn) |
779 | continue; |
780 | goto next; |
781 | case NS_CMPRSFLGS: /*%< indirection */ |
782 | cp = msg + (((n & 0x3f) << 8) | *cp); |
783 | break; |
784 | |
785 | default: /*%< illegal type */ |
786 | __set_errno (EMSGSIZE); |
787 | return (-1); |
788 | } |
789 | } |
790 | next: ; |
791 | sp += *sp + 1; |
792 | } |
793 | } |
794 | __set_errno (ENOENT); |
795 | return (-1); |
796 | } |
797 | |
798 | static int |
799 | decode_bitstring(const unsigned char **cpp, char *dn, const char *eom) |
800 | { |
801 | const unsigned char *cp = *cpp; |
802 | char *beg = dn, tc; |
803 | int b, blen, plen, i; |
804 | |
805 | if ((blen = (*cp & 0xff)) == 0) |
806 | blen = 256; |
807 | plen = (blen + 3) / 4; |
808 | plen += sizeof("\\[x/]" ) + (blen > 99 ? 3 : (blen > 9) ? 2 : 1); |
809 | if (dn + plen >= eom) |
810 | return(-1); |
811 | |
812 | cp++; |
813 | i = SPRINTF((dn, "\\[x" )); |
814 | if (i < 0) |
815 | return (-1); |
816 | dn += i; |
817 | for (b = blen; b > 7; b -= 8, cp++) { |
818 | i = SPRINTF((dn, "%02x" , *cp & 0xff)); |
819 | if (i < 0) |
820 | return (-1); |
821 | dn += i; |
822 | } |
823 | if (b > 4) { |
824 | tc = *cp++; |
825 | i = SPRINTF((dn, "%02x" , tc & (0xff << (8 - b)))); |
826 | if (i < 0) |
827 | return (-1); |
828 | dn += i; |
829 | } else if (b > 0) { |
830 | tc = *cp++; |
831 | i = SPRINTF((dn, "%1x" , |
832 | ((tc >> 4) & 0x0f) & (0x0f << (4 - b)))); |
833 | if (i < 0) |
834 | return (-1); |
835 | dn += i; |
836 | } |
837 | i = SPRINTF((dn, "/%d]" , blen)); |
838 | if (i < 0) |
839 | return (-1); |
840 | dn += i; |
841 | |
842 | *cpp = cp; |
843 | return(dn - beg); |
844 | } |
845 | |
846 | static int |
847 | encode_bitstring(const char **bp, const char *end, unsigned char **labelp, |
848 | unsigned char ** dst, unsigned const char *eom) |
849 | { |
850 | int afterslash = 0; |
851 | const char *cp = *bp; |
852 | unsigned char *tp; |
853 | char c; |
854 | const char *beg_blen; |
855 | char *end_blen = NULL; |
856 | int value = 0, count = 0, tbcount = 0, blen = 0; |
857 | |
858 | beg_blen = end_blen = NULL; |
859 | |
860 | /* a bitstring must contain at least 2 characters */ |
861 | if (end - cp < 2) |
862 | return(EINVAL); |
863 | |
864 | /* XXX: currently, only hex strings are supported */ |
865 | if (*cp++ != 'x') |
866 | return(EINVAL); |
867 | if (!isxdigit((*cp) & 0xff)) /*%< reject '\[x/BLEN]' */ |
868 | return(EINVAL); |
869 | |
870 | for (tp = *dst + 1; cp < end && tp < eom; cp++) { |
871 | switch((c = *cp)) { |
872 | case ']': /*%< end of the bitstring */ |
873 | if (afterslash) { |
874 | if (beg_blen == NULL) |
875 | return(EINVAL); |
876 | blen = (int)strtol(beg_blen, &end_blen, 10); |
877 | if (*end_blen != ']') |
878 | return(EINVAL); |
879 | } |
880 | if (count) |
881 | *tp++ = ((value << 4) & 0xff); |
882 | cp++; /*%< skip ']' */ |
883 | goto done; |
884 | case '/': |
885 | afterslash = 1; |
886 | break; |
887 | default: |
888 | if (afterslash) { |
889 | if (!isdigit(c&0xff)) |
890 | return(EINVAL); |
891 | if (beg_blen == NULL) { |
892 | |
893 | if (c == '0') { |
894 | /* blen never begings with 0 */ |
895 | return(EINVAL); |
896 | } |
897 | beg_blen = cp; |
898 | } |
899 | } else { |
900 | if (!isxdigit(c&0xff)) |
901 | return(EINVAL); |
902 | value <<= 4; |
903 | value += digitvalue[(int)c]; |
904 | count += 4; |
905 | tbcount += 4; |
906 | if (tbcount > 256) |
907 | return(EINVAL); |
908 | if (count == 8) { |
909 | *tp++ = value; |
910 | count = 0; |
911 | } |
912 | } |
913 | break; |
914 | } |
915 | } |
916 | done: |
917 | if (cp >= end || tp >= eom) |
918 | return(EMSGSIZE); |
919 | |
920 | /* |
921 | * bit length validation: |
922 | * If a <length> is present, the number of digits in the <bit-data> |
923 | * MUST be just sufficient to contain the number of bits specified |
924 | * by the <length>. If there are insignificant bits in a final |
925 | * hexadecimal or octal digit, they MUST be zero. |
926 | * RFC2673, Section 3.2. |
927 | */ |
928 | if (blen > 0) { |
929 | int traillen; |
930 | |
931 | if (((blen + 3) & ~3) != tbcount) |
932 | return(EINVAL); |
933 | traillen = tbcount - blen; /*%< between 0 and 3 */ |
934 | if (((value << (8 - traillen)) & 0xff) != 0) |
935 | return(EINVAL); |
936 | } |
937 | else |
938 | blen = tbcount; |
939 | if (blen == 256) |
940 | blen = 0; |
941 | |
942 | /* encode the type and the significant bit fields */ |
943 | **labelp = DNS_LABELTYPE_BITSTRING; |
944 | **dst = blen; |
945 | |
946 | *bp = cp; |
947 | *dst = tp; |
948 | |
949 | return(0); |
950 | } |
951 | |
952 | static int |
953 | labellen(const u_char *lp) |
954 | { |
955 | int bitlen; |
956 | u_char l = *lp; |
957 | |
958 | if ((l & NS_CMPRSFLGS) == NS_CMPRSFLGS) { |
959 | /* should be avoided by the caller */ |
960 | return(-1); |
961 | } |
962 | |
963 | if ((l & NS_CMPRSFLGS) == NS_TYPE_ELT) { |
964 | if (l == DNS_LABELTYPE_BITSTRING) { |
965 | if ((bitlen = *(lp + 1)) == 0) |
966 | bitlen = 256; |
967 | return((bitlen + 7 ) / 8 + 1); |
968 | } |
969 | return(-1); /*%< unknwon ELT */ |
970 | } |
971 | return(l); |
972 | } |
973 | |
974 | /*! \file */ |
975 | |