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 #ifndef lint
19 static const char rcsid[] = "$Id: ns_name.c,v 1.11 2009/01/23 19:59:16 each Exp $";
20 #endif
21 #include <sys/cdefs.h>
22 __FBSDID("$FreeBSD$");
23
24 #include "port_before.h"
25
26 #include <sys/types.h>
27
28 #include <netinet/in.h>
29 #include <arpa/nameser.h>
30
31 #include <errno.h>
32 #include <resolv.h>
33 #include <string.h>
34 #include <ctype.h>
35 #include <stdlib.h>
36 #include <limits.h>
37
38 #include "port_after.h"
39
40 #ifdef SPRINTF_CHAR
41 # define SPRINTF(x) strlen(sprintf/**/x)
42 #else
43 # define SPRINTF(x) ((size_t)sprintf x)
44 #endif
45
46 #define NS_TYPE_ELT 0x40 /*%< EDNS0 extended label type */
47 #define DNS_LABELTYPE_BITSTRING 0x41
48
49 /* Data. */
50
51 static const char digits[] = "0123456789";
52
53 static const char digitvalue[256] = {
54 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*16*/
55 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*32*/
56 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*48*/
57 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -1, -1, -1, -1, -1, -1, /*64*/
58 -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*80*/
59 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*96*/
60 -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*112*/
61 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*128*/
62 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
63 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
64 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
65 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
66 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
67 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
68 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
69 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*256*/
70 };
71
72 /* Forward. */
73
74 static int special(int);
75 static int printable(int);
76 static int dn_find(const u_char *, const u_char *,
77 const u_char * const *,
78 const u_char * const *);
79 static int encode_bitsring(const char **, const char *,
80 unsigned char **, unsigned char **,
81 unsigned const char *);
82 static int labellen(const u_char *);
83 static int decode_bitstring(const unsigned char **,
84 char *, const char *);
85
86 /* Public. */
87
88 /*%
89 * Convert an encoded domain name to printable ascii as per RFC1035.
90
91 * return:
92 *\li Number of bytes written to buffer, or -1 (with errno set)
93 *
94 * notes:
95 *\li The root is returned as "."
96 *\li All other domains are returned in non absolute form
97 */
98 int
ns_name_ntop(const u_char * src,char * dst,size_t dstsiz)99 ns_name_ntop(const u_char *src, char *dst, size_t dstsiz)
100 {
101 const u_char *cp;
102 char *dn, *eom;
103 u_char c;
104 u_int n;
105 int l;
106
107 cp = src;
108 dn = dst;
109 eom = dst + dstsiz;
110
111 while ((n = *cp++) != 0) {
112 if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
113 /* Some kind of compression pointer. */
114 errno = EMSGSIZE;
115 return (-1);
116 }
117 if (dn != dst) {
118 if (dn >= eom) {
119 errno = EMSGSIZE;
120 return (-1);
121 }
122 *dn++ = '.';
123 }
124 if ((l = labellen(cp - 1)) < 0) {
125 errno = EMSGSIZE; /*%< XXX */
126 return (-1);
127 }
128 if (dn + l >= eom) {
129 errno = EMSGSIZE;
130 return (-1);
131 }
132 if ((n & NS_CMPRSFLGS) == NS_TYPE_ELT) {
133 int m;
134
135 if (n != DNS_LABELTYPE_BITSTRING) {
136 /* XXX: labellen should reject this case */
137 errno = EINVAL;
138 return (-1);
139 }
140 if ((m = decode_bitstring(&cp, dn, eom)) < 0)
141 {
142 errno = EMSGSIZE;
143 return (-1);
144 }
145 dn += m;
146 continue;
147 }
148 for ((void)NULL; l > 0; l--) {
149 c = *cp++;
150 if (special(c)) {
151 if (dn + 1 >= eom) {
152 errno = EMSGSIZE;
153 return (-1);
154 }
155 *dn++ = '\\';
156 *dn++ = (char)c;
157 } else if (!printable(c)) {
158 if (dn + 3 >= eom) {
159 errno = EMSGSIZE;
160 return (-1);
161 }
162 *dn++ = '\\';
163 *dn++ = digits[c / 100];
164 *dn++ = digits[(c % 100) / 10];
165 *dn++ = digits[c % 10];
166 } else {
167 if (dn >= eom) {
168 errno = EMSGSIZE;
169 return (-1);
170 }
171 *dn++ = (char)c;
172 }
173 }
174 }
175 if (dn == dst) {
176 if (dn >= eom) {
177 errno = EMSGSIZE;
178 return (-1);
179 }
180 *dn++ = '.';
181 }
182 if (dn >= eom) {
183 errno = EMSGSIZE;
184 return (-1);
185 }
186 *dn++ = '\0';
187 return (dn - dst);
188 }
189
190 /*%
191 * Convert a ascii string into an encoded domain name as per RFC1035.
192 *
193 * return:
194 *
195 *\li -1 if it fails
196 *\li 1 if string was fully qualified
197 *\li 0 is string was not fully qualified
198 *
199 * notes:
200 *\li Enforces label and domain length limits.
201 */
202 int
ns_name_pton(const char * src,u_char * dst,size_t dstsiz)203 ns_name_pton(const char *src, u_char *dst, size_t dstsiz) {
204 return (ns_name_pton2(src, dst, dstsiz, NULL));
205 }
206
207 /*
208 * ns_name_pton2(src, dst, dstsiz, *dstlen)
209 * Convert a ascii string into an encoded domain name as per RFC1035.
210 * return:
211 * -1 if it fails
212 * 1 if string was fully qualified
213 * 0 is string was not fully qualified
214 * side effects:
215 * fills in *dstlen (if non-NULL)
216 * notes:
217 * Enforces label and domain length limits.
218 */
219 int
ns_name_pton2(const char * src,u_char * dst,size_t dstsiz,size_t * dstlen)220 ns_name_pton2(const char *src, u_char *dst, size_t dstsiz, size_t *dstlen) {
221 u_char *label, *bp, *eom;
222 int c, n, escaped, e = 0;
223 char *cp;
224
225 escaped = 0;
226 bp = dst;
227 eom = dst + dstsiz;
228 label = bp++;
229
230 while ((c = *src++) != 0) {
231 if (escaped) {
232 if (c == '[') { /*%< start a bit string label */
233 if ((cp = strchr(src, ']')) == NULL) {
234 errno = EINVAL; /*%< ??? */
235 return (-1);
236 }
237 if ((e = encode_bitsring(&src, cp + 2,
238 &label, &bp, eom))
239 != 0) {
240 errno = e;
241 return (-1);
242 }
243 escaped = 0;
244 label = bp++;
245 if ((c = *src++) == 0)
246 goto done;
247 else if (c != '.') {
248 errno = EINVAL;
249 return (-1);
250 }
251 continue;
252 }
253 else if ((cp = strchr(digits, c)) != NULL) {
254 n = (cp - digits) * 100;
255 if ((c = *src++) == 0 ||
256 (cp = strchr(digits, c)) == NULL) {
257 errno = EMSGSIZE;
258 return (-1);
259 }
260 n += (cp - digits) * 10;
261 if ((c = *src++) == 0 ||
262 (cp = strchr(digits, c)) == NULL) {
263 errno = EMSGSIZE;
264 return (-1);
265 }
266 n += (cp - digits);
267 if (n > 255) {
268 errno = EMSGSIZE;
269 return (-1);
270 }
271 c = n;
272 }
273 escaped = 0;
274 } else if (c == '\\') {
275 escaped = 1;
276 continue;
277 } else if (c == '.') {
278 c = (bp - label - 1);
279 if ((c & NS_CMPRSFLGS) != 0) { /*%< Label too big. */
280 errno = EMSGSIZE;
281 return (-1);
282 }
283 if (label >= eom) {
284 errno = EMSGSIZE;
285 return (-1);
286 }
287 *label = c;
288 /* Fully qualified ? */
289 if (*src == '\0') {
290 if (c != 0) {
291 if (bp >= eom) {
292 errno = EMSGSIZE;
293 return (-1);
294 }
295 *bp++ = '\0';
296 }
297 if ((bp - dst) > MAXCDNAME) {
298 errno = EMSGSIZE;
299 return (-1);
300 }
301 if (dstlen != NULL)
302 *dstlen = (bp - dst);
303 return (1);
304 }
305 if (c == 0 || *src == '.') {
306 errno = EMSGSIZE;
307 return (-1);
308 }
309 label = bp++;
310 continue;
311 }
312 if (bp >= eom) {
313 errno = EMSGSIZE;
314 return (-1);
315 }
316 *bp++ = (u_char)c;
317 }
318 c = (bp - label - 1);
319 if ((c & NS_CMPRSFLGS) != 0) { /*%< Label too big. */
320 errno = EMSGSIZE;
321 return (-1);
322 }
323 done:
324 if (label >= eom) {
325 errno = EMSGSIZE;
326 return (-1);
327 }
328 *label = c;
329 if (c != 0) {
330 if (bp >= eom) {
331 errno = EMSGSIZE;
332 return (-1);
333 }
334 *bp++ = 0;
335 }
336 if ((bp - dst) > MAXCDNAME) { /*%< src too big */
337 errno = EMSGSIZE;
338 return (-1);
339 }
340 if (dstlen != NULL)
341 *dstlen = (bp - dst);
342 return (0);
343 }
344
345 /*%
346 * Convert a network strings labels into all lowercase.
347 *
348 * return:
349 *\li Number of bytes written to buffer, or -1 (with errno set)
350 *
351 * notes:
352 *\li Enforces label and domain length limits.
353 */
354
355 int
ns_name_ntol(const u_char * src,u_char * dst,size_t dstsiz)356 ns_name_ntol(const u_char *src, u_char *dst, size_t dstsiz)
357 {
358 const u_char *cp;
359 u_char *dn, *eom;
360 u_char c;
361 u_int n;
362 int l;
363
364 cp = src;
365 dn = dst;
366 eom = dst + dstsiz;
367
368 if (dn >= eom) {
369 errno = EMSGSIZE;
370 return (-1);
371 }
372 while ((n = *cp++) != 0) {
373 if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
374 /* Some kind of compression pointer. */
375 errno = EMSGSIZE;
376 return (-1);
377 }
378 *dn++ = n;
379 if ((l = labellen(cp - 1)) < 0) {
380 errno = EMSGSIZE;
381 return (-1);
382 }
383 if (dn + l >= eom) {
384 errno = EMSGSIZE;
385 return (-1);
386 }
387 for ((void)NULL; l > 0; l--) {
388 c = *cp++;
389 if (isascii(c) && isupper(c))
390 *dn++ = tolower(c);
391 else
392 *dn++ = c;
393 }
394 }
395 *dn++ = '\0';
396 return (dn - dst);
397 }
398
399 /*%
400 * Unpack a domain name from a message, source may be compressed.
401 *
402 * return:
403 *\li -1 if it fails, or consumed octets if it succeeds.
404 */
405 int
ns_name_unpack(const u_char * msg,const u_char * eom,const u_char * src,u_char * dst,size_t dstsiz)406 ns_name_unpack(const u_char *msg, const u_char *eom, const u_char *src,
407 u_char *dst, size_t dstsiz)
408 {
409 return (ns_name_unpack2(msg, eom, src, dst, dstsiz, NULL));
410 }
411
412 /*
413 * ns_name_unpack2(msg, eom, src, dst, dstsiz, *dstlen)
414 * Unpack a domain name from a message, source may be compressed.
415 * return:
416 * -1 if it fails, or consumed octets if it succeeds.
417 * side effect:
418 * fills in *dstlen (if non-NULL).
419 */
420 int
ns_name_unpack2(const u_char * msg,const u_char * eom,const u_char * src,u_char * dst,size_t dstsiz,size_t * dstlen)421 ns_name_unpack2(const u_char *msg, const u_char *eom, const u_char *src,
422 u_char *dst, size_t dstsiz, size_t *dstlen)
423 {
424 const u_char *srcp, *dstlim;
425 u_char *dstp;
426 int n, len, checked, l;
427
428 len = -1;
429 checked = 0;
430 dstp = dst;
431 srcp = src;
432 dstlim = dst + dstsiz;
433 if (srcp < msg || srcp >= eom) {
434 errno = EMSGSIZE;
435 return (-1);
436 }
437 /* Fetch next label in domain name. */
438 while ((n = *srcp++) != 0) {
439 /* Check for indirection. */
440 switch (n & NS_CMPRSFLGS) {
441 case 0:
442 case NS_TYPE_ELT:
443 /* Limit checks. */
444 if ((l = labellen(srcp - 1)) < 0) {
445 errno = EMSGSIZE;
446 return (-1);
447 }
448 if (dstp + l + 1 >= dstlim || srcp + l >= eom) {
449 errno = EMSGSIZE;
450 return (-1);
451 }
452 checked += l + 1;
453 *dstp++ = n;
454 memcpy(dstp, srcp, l);
455 dstp += l;
456 srcp += l;
457 break;
458
459 case NS_CMPRSFLGS:
460 if (srcp >= eom) {
461 errno = EMSGSIZE;
462 return (-1);
463 }
464 if (len < 0)
465 len = srcp - src + 1;
466 l = ((n & 0x3f) << 8) | (*srcp & 0xff);
467 if (l >= eom - msg) { /*%< Out of range. */
468 errno = EMSGSIZE;
469 return (-1);
470 }
471 srcp = msg + l;
472 checked += 2;
473 /*
474 * Check for loops in the compressed name;
475 * if we've looked at the whole message,
476 * there must be a loop.
477 */
478 if (checked >= eom - msg) {
479 errno = EMSGSIZE;
480 return (-1);
481 }
482 break;
483
484 default:
485 errno = EMSGSIZE;
486 return (-1); /*%< flag error */
487 }
488 }
489 *dstp++ = 0;
490 if (dstlen != NULL)
491 *dstlen = dstp - dst;
492 if (len < 0)
493 len = srcp - src;
494 return (len);
495 }
496
497 /*%
498 * Pack domain name 'domain' into 'comp_dn'.
499 *
500 * return:
501 *\li Size of the compressed name, or -1.
502 *
503 * notes:
504 *\li 'dnptrs' is an array of pointers to previous compressed names.
505 *\li dnptrs[0] is a pointer to the beginning of the message. The array
506 * ends with NULL.
507 *\li 'lastdnptr' is a pointer to the end of the array pointed to
508 * by 'dnptrs'.
509 *
510 * Side effects:
511 *\li The list of pointers in dnptrs is updated for labels inserted into
512 * the message as we compress the name. If 'dnptr' is NULL, we don't
513 * try to compress names. If 'lastdnptr' is NULL, we don't update the
514 * list.
515 */
516 int
ns_name_pack(const u_char * src,u_char * dst,int dstsiz,const u_char ** dnptrs,const u_char ** lastdnptr)517 ns_name_pack(const u_char *src, u_char *dst, int dstsiz,
518 const u_char **dnptrs, const u_char **lastdnptr)
519 {
520 u_char *dstp;
521 const u_char **cpp, **lpp, *eob, *msg;
522 const u_char *srcp;
523 int n, l, first = 1;
524
525 srcp = src;
526 dstp = dst;
527 eob = dstp + dstsiz;
528 lpp = cpp = NULL;
529 if (dnptrs != NULL) {
530 if ((msg = *dnptrs++) != NULL) {
531 for (cpp = dnptrs; *cpp != NULL; cpp++)
532 (void)NULL;
533 lpp = cpp; /*%< end of list to search */
534 }
535 } else
536 msg = NULL;
537
538 /* make sure the domain we are about to add is legal */
539 l = 0;
540 do {
541 int l0;
542
543 n = *srcp;
544 if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
545 errno = EMSGSIZE;
546 return (-1);
547 }
548 if ((l0 = labellen(srcp)) < 0) {
549 errno = EINVAL;
550 return (-1);
551 }
552 l += l0 + 1;
553 if (l > MAXCDNAME) {
554 errno = EMSGSIZE;
555 return (-1);
556 }
557 srcp += l0 + 1;
558 } while (n != 0);
559
560 /* from here on we need to reset compression pointer array on error */
561 srcp = src;
562 do {
563 /* Look to see if we can use pointers. */
564 n = *srcp;
565 if (n != 0 && msg != NULL) {
566 l = dn_find(srcp, msg, (const u_char * const *)dnptrs,
567 (const u_char * const *)lpp);
568 if (l >= 0) {
569 if (dstp + 1 >= eob) {
570 goto cleanup;
571 }
572 *dstp++ = (l >> 8) | NS_CMPRSFLGS;
573 *dstp++ = l % 256;
574 return (dstp - dst);
575 }
576 /* Not found, save it. */
577 if (lastdnptr != NULL && cpp < lastdnptr - 1 &&
578 (dstp - msg) < 0x4000 && first) {
579 *cpp++ = dstp;
580 *cpp = NULL;
581 first = 0;
582 }
583 }
584 /* copy label to buffer */
585 if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
586 /* Should not happen. */
587 goto cleanup;
588 }
589 n = labellen(srcp);
590 if (dstp + 1 + n >= eob) {
591 goto cleanup;
592 }
593 memcpy(dstp, srcp, n + 1);
594 srcp += n + 1;
595 dstp += n + 1;
596 } while (n != 0);
597
598 if (dstp > eob) {
599 cleanup:
600 if (msg != NULL)
601 *lpp = NULL;
602 errno = EMSGSIZE;
603 return (-1);
604 }
605 return (dstp - dst);
606 }
607
608 /*%
609 * Expand compressed domain name to presentation format.
610 *
611 * return:
612 *\li Number of bytes read out of `src', or -1 (with errno set).
613 *
614 * note:
615 *\li Root domain returns as "." not "".
616 */
617 int
ns_name_uncompress(const u_char * msg,const u_char * eom,const u_char * src,char * dst,size_t dstsiz)618 ns_name_uncompress(const u_char *msg, const u_char *eom, const u_char *src,
619 char *dst, size_t dstsiz)
620 {
621 u_char tmp[NS_MAXCDNAME];
622 int n;
623
624 if ((n = ns_name_unpack(msg, eom, src, tmp, sizeof tmp)) == -1)
625 return (-1);
626 if (ns_name_ntop(tmp, dst, dstsiz) == -1)
627 return (-1);
628 return (n);
629 }
630
631 /*%
632 * Compress a domain name into wire format, using compression pointers.
633 *
634 * return:
635 *\li Number of bytes consumed in `dst' or -1 (with errno set).
636 *
637 * notes:
638 *\li 'dnptrs' is an array of pointers to previous compressed names.
639 *\li dnptrs[0] is a pointer to the beginning of the message.
640 *\li The list ends with NULL. 'lastdnptr' is a pointer to the end of the
641 * array pointed to by 'dnptrs'. Side effect is to update the list of
642 * pointers for labels inserted into the message as we compress the name.
643 *\li If 'dnptr' is NULL, we don't try to compress names. If 'lastdnptr'
644 * is NULL, we don't update the list.
645 */
646 int
ns_name_compress(const char * src,u_char * dst,size_t dstsiz,const u_char ** dnptrs,const u_char ** lastdnptr)647 ns_name_compress(const char *src, u_char *dst, size_t dstsiz,
648 const u_char **dnptrs, const u_char **lastdnptr)
649 {
650 u_char tmp[NS_MAXCDNAME];
651
652 if (ns_name_pton(src, tmp, sizeof tmp) == -1)
653 return (-1);
654 return (ns_name_pack(tmp, dst, dstsiz, dnptrs, lastdnptr));
655 }
656
657 /*%
658 * Reset dnptrs so that there are no active references to pointers at or
659 * after src.
660 */
661 void
ns_name_rollback(const u_char * src,const u_char ** dnptrs,const u_char ** lastdnptr)662 ns_name_rollback(const u_char *src, const u_char **dnptrs,
663 const u_char **lastdnptr)
664 {
665 while (dnptrs < lastdnptr && *dnptrs != NULL) {
666 if (*dnptrs >= src) {
667 *dnptrs = NULL;
668 break;
669 }
670 dnptrs++;
671 }
672 }
673
674 /*%
675 * Advance *ptrptr to skip over the compressed name it points at.
676 *
677 * return:
678 *\li 0 on success, -1 (with errno set) on failure.
679 */
680 int
ns_name_skip(const u_char ** ptrptr,const u_char * eom)681 ns_name_skip(const u_char **ptrptr, const u_char *eom)
682 {
683 const u_char *cp;
684 u_int n;
685 int l;
686
687 cp = *ptrptr;
688 while (cp < eom && (n = *cp++) != 0) {
689 /* Check for indirection. */
690 switch (n & NS_CMPRSFLGS) {
691 case 0: /*%< normal case, n == len */
692 cp += n;
693 continue;
694 case NS_TYPE_ELT: /*%< EDNS0 extended label */
695 if ((l = labellen(cp - 1)) < 0) {
696 errno = EMSGSIZE; /*%< XXX */
697 return (-1);
698 }
699 cp += l;
700 continue;
701 case NS_CMPRSFLGS: /*%< indirection */
702 cp++;
703 break;
704 default: /*%< illegal type */
705 errno = EMSGSIZE;
706 return (-1);
707 }
708 break;
709 }
710 if (cp > eom) {
711 errno = EMSGSIZE;
712 return (-1);
713 }
714 *ptrptr = cp;
715 return (0);
716 }
717
718 /* Find the number of octets an nname takes up, including the root label.
719 * (This is basically ns_name_skip() without compression-pointer support.)
720 * ((NOTE: can only return zero if passed-in namesiz argument is zero.))
721 */
722 ssize_t
ns_name_length(ns_nname_ct nname,size_t namesiz)723 ns_name_length(ns_nname_ct nname, size_t namesiz) {
724 ns_nname_ct orig = nname;
725 u_int n;
726
727 while (namesiz-- > 0 && (n = *nname++) != 0) {
728 if ((n & NS_CMPRSFLGS) != 0) {
729 errno = EISDIR;
730 return (-1);
731 }
732 if (n > namesiz) {
733 errno = EMSGSIZE;
734 return (-1);
735 }
736 nname += n;
737 namesiz -= n;
738 }
739 return (nname - orig);
740 }
741
742 /* Compare two nname's for equality. Return -1 on error (setting errno).
743 */
744 int
ns_name_eq(ns_nname_ct a,size_t as,ns_nname_ct b,size_t bs)745 ns_name_eq(ns_nname_ct a, size_t as, ns_nname_ct b, size_t bs) {
746 ns_nname_ct ae = a + as, be = b + bs;
747 int ac, bc;
748
749 while (ac = *a, bc = *b, ac != 0 && bc != 0) {
750 if ((ac & NS_CMPRSFLGS) != 0 || (bc & NS_CMPRSFLGS) != 0) {
751 errno = EISDIR;
752 return (-1);
753 }
754 if (a + ac >= ae || b + bc >= be) {
755 errno = EMSGSIZE;
756 return (-1);
757 }
758 if (ac != bc || strncasecmp((const char *) ++a,
759 (const char *) ++b, ac) != 0)
760 return (0);
761 a += ac, b += bc;
762 }
763 return (ac == 0 && bc == 0);
764 }
765
766 /* Is domain "A" owned by (at or below) domain "B"?
767 */
768 int
ns_name_owned(ns_namemap_ct a,int an,ns_namemap_ct b,int bn)769 ns_name_owned(ns_namemap_ct a, int an, ns_namemap_ct b, int bn) {
770 /* If A is shorter, it cannot be owned by B. */
771 if (an < bn)
772 return (0);
773
774 /* If they are unequal before the length of the shorter, A cannot... */
775 while (bn > 0) {
776 if (a->len != b->len ||
777 strncasecmp((const char *) a->base,
778 (const char *) b->base, a->len) != 0)
779 return (0);
780 a++, an--;
781 b++, bn--;
782 }
783
784 /* A might be longer or not, but either way, B owns it. */
785 return (1);
786 }
787
788 /* Build an array of <base,len> tuples from an nname, top-down order.
789 * Return the number of tuples (labels) thus discovered.
790 */
791 int
ns_name_map(ns_nname_ct nname,size_t namelen,ns_namemap_t map,int mapsize)792 ns_name_map(ns_nname_ct nname, size_t namelen, ns_namemap_t map, int mapsize) {
793 u_int n;
794 int l;
795
796 n = *nname++;
797 namelen--;
798
799 /* Root zone? */
800 if (n == 0) {
801 /* Extra data follows name? */
802 if (namelen > 0) {
803 errno = EMSGSIZE;
804 return (-1);
805 }
806 return (0);
807 }
808
809 /* Compression pointer? */
810 if ((n & NS_CMPRSFLGS) != 0) {
811 errno = EISDIR;
812 return (-1);
813 }
814
815 /* Label too long? */
816 if (n > namelen) {
817 errno = EMSGSIZE;
818 return (-1);
819 }
820
821 /* Recurse to get rest of name done first. */
822 l = ns_name_map(nname + n, namelen - n, map, mapsize);
823 if (l < 0)
824 return (-1);
825
826 /* Too many labels? */
827 if (l >= mapsize) {
828 errno = ENAMETOOLONG;
829 return (-1);
830 }
831
832 /* We're on our way back up-stack, store current map data. */
833 map[l].base = nname;
834 map[l].len = n;
835 return (l + 1);
836 }
837
838 /* Count the labels in a domain name. Root counts, so COM. has two. This
839 * is to make the result comparable to the result of ns_name_map().
840 */
841 int
ns_name_labels(ns_nname_ct nname,size_t namesiz)842 ns_name_labels(ns_nname_ct nname, size_t namesiz) {
843 int ret = 0;
844 u_int n;
845
846 while (namesiz-- > 0 && (n = *nname++) != 0) {
847 if ((n & NS_CMPRSFLGS) != 0) {
848 errno = EISDIR;
849 return (-1);
850 }
851 if (n > namesiz) {
852 errno = EMSGSIZE;
853 return (-1);
854 }
855 nname += n;
856 namesiz -= n;
857 ret++;
858 }
859 return (ret + 1);
860 }
861
862 /* Private. */
863
864 /*%
865 * Thinking in noninternationalized USASCII (per the DNS spec),
866 * is this characted special ("in need of quoting") ?
867 *
868 * return:
869 *\li boolean.
870 */
871 static int
special(int ch)872 special(int ch) {
873 switch (ch) {
874 case 0x22: /*%< '"' */
875 case 0x2E: /*%< '.' */
876 case 0x3B: /*%< ';' */
877 case 0x5C: /*%< '\\' */
878 case 0x28: /*%< '(' */
879 case 0x29: /*%< ')' */
880 /* Special modifiers in zone files. */
881 case 0x40: /*%< '@' */
882 case 0x24: /*%< '$' */
883 return (1);
884 default:
885 return (0);
886 }
887 }
888
889 /*%
890 * Thinking in noninternationalized USASCII (per the DNS spec),
891 * is this character visible and not a space when printed ?
892 *
893 * return:
894 *\li boolean.
895 */
896 static int
printable(int ch)897 printable(int ch) {
898 return (ch > 0x20 && ch < 0x7f);
899 }
900
901 /*%
902 * Thinking in noninternationalized USASCII (per the DNS spec),
903 * convert this character to lower case if it's upper case.
904 */
905 static int
mklower(int ch)906 mklower(int ch) {
907 if (ch >= 0x41 && ch <= 0x5A)
908 return (ch + 0x20);
909 return (ch);
910 }
911
912 /*%
913 * Search for the counted-label name in an array of compressed names.
914 *
915 * return:
916 *\li offset from msg if found, or -1.
917 *
918 * notes:
919 *\li dnptrs is the pointer to the first name on the list,
920 *\li not the pointer to the start of the message.
921 */
922 static int
dn_find(const u_char * domain,const u_char * msg,const u_char * const * dnptrs,const u_char * const * lastdnptr)923 dn_find(const u_char *domain, const u_char *msg,
924 const u_char * const *dnptrs,
925 const u_char * const *lastdnptr)
926 {
927 const u_char *dn, *cp, *sp;
928 const u_char * const *cpp;
929 u_int n;
930
931 for (cpp = dnptrs; cpp < lastdnptr; cpp++) {
932 sp = *cpp;
933 /*
934 * terminate search on:
935 * root label
936 * compression pointer
937 * unusable offset
938 */
939 while (*sp != 0 && (*sp & NS_CMPRSFLGS) == 0 &&
940 (sp - msg) < 0x4000) {
941 dn = domain;
942 cp = sp;
943 while ((n = *cp++) != 0) {
944 /*
945 * check for indirection
946 */
947 switch (n & NS_CMPRSFLGS) {
948 case 0: /*%< normal case, n == len */
949 n = labellen(cp - 1); /*%< XXX */
950 if (n != *dn++)
951 goto next;
952
953 for ((void)NULL; n > 0; n--)
954 if (mklower(*dn++) !=
955 mklower(*cp++))
956 goto next;
957 /* Is next root for both ? */
958 if (*dn == '\0' && *cp == '\0')
959 return (sp - msg);
960 if (*dn)
961 continue;
962 goto next;
963 case NS_CMPRSFLGS: /*%< indirection */
964 cp = msg + (((n & 0x3f) << 8) | *cp);
965 break;
966
967 default: /*%< illegal type */
968 errno = EMSGSIZE;
969 return (-1);
970 }
971 }
972 next: ;
973 sp += *sp + 1;
974 }
975 }
976 errno = ENOENT;
977 return (-1);
978 }
979
980 static int
decode_bitstring(const unsigned char ** cpp,char * dn,const char * eom)981 decode_bitstring(const unsigned char **cpp, char *dn, const char *eom)
982 {
983 const unsigned char *cp = *cpp;
984 char *beg = dn, tc;
985 int b, blen, plen, i;
986
987 if ((blen = (*cp & 0xff)) == 0)
988 blen = 256;
989 plen = (blen + 3) / 4;
990 plen += sizeof("\\[x/]") + (blen > 99 ? 3 : (blen > 9) ? 2 : 1);
991 if (dn + plen >= eom)
992 return (-1);
993
994 cp++;
995 i = SPRINTF((dn, "\\[x"));
996 if (i < 0)
997 return (-1);
998 dn += i;
999 for (b = blen; b > 7; b -= 8, cp++) {
1000 i = SPRINTF((dn, "%02x", *cp & 0xff));
1001 if (i < 0)
1002 return (-1);
1003 dn += i;
1004 }
1005 if (b > 4) {
1006 tc = *cp++;
1007 i = SPRINTF((dn, "%02x", tc & (0xff << (8 - b))));
1008 if (i < 0)
1009 return (-1);
1010 dn += i;
1011 } else if (b > 0) {
1012 tc = *cp++;
1013 i = SPRINTF((dn, "%1x",
1014 ((tc >> 4) & 0x0f) & (0x0f << (4 - b))));
1015 if (i < 0)
1016 return (-1);
1017 dn += i;
1018 }
1019 i = SPRINTF((dn, "/%d]", blen));
1020 if (i < 0)
1021 return (-1);
1022 dn += i;
1023
1024 *cpp = cp;
1025 return (dn - beg);
1026 }
1027
1028 static int
encode_bitsring(const char ** bp,const char * end,unsigned char ** labelp,unsigned char ** dst,unsigned const char * eom)1029 encode_bitsring(const char **bp, const char *end, unsigned char **labelp,
1030 unsigned char ** dst, unsigned const char *eom)
1031 {
1032 int afterslash = 0;
1033 const char *cp = *bp;
1034 unsigned char *tp;
1035 char c;
1036 const char *beg_blen;
1037 char *end_blen = NULL;
1038 int value = 0, count = 0, tbcount = 0, blen = 0;
1039
1040 beg_blen = end_blen = NULL;
1041
1042 /* a bitstring must contain at least 2 characters */
1043 if (end - cp < 2)
1044 return (EINVAL);
1045
1046 /* XXX: currently, only hex strings are supported */
1047 if (*cp++ != 'x')
1048 return (EINVAL);
1049 if (!isxdigit((*cp) & 0xff)) /*%< reject '\[x/BLEN]' */
1050 return (EINVAL);
1051
1052 for (tp = *dst + 1; cp < end && tp < eom; cp++) {
1053 switch((c = *cp)) {
1054 case ']': /*%< end of the bitstring */
1055 if (afterslash) {
1056 if (beg_blen == NULL)
1057 return (EINVAL);
1058 blen = (int)strtol(beg_blen, &end_blen, 10);
1059 if (*end_blen != ']')
1060 return (EINVAL);
1061 }
1062 if (count)
1063 *tp++ = ((value << 4) & 0xff);
1064 cp++; /*%< skip ']' */
1065 goto done;
1066 case '/':
1067 afterslash = 1;
1068 break;
1069 default:
1070 if (afterslash) {
1071 if (!isdigit(c&0xff))
1072 return (EINVAL);
1073 if (beg_blen == NULL) {
1074
1075 if (c == '0') {
1076 /* blen never begings with 0 */
1077 return (EINVAL);
1078 }
1079 beg_blen = cp;
1080 }
1081 } else {
1082 if (!isxdigit(c&0xff))
1083 return (EINVAL);
1084 value <<= 4;
1085 value += digitvalue[(int)c];
1086 count += 4;
1087 tbcount += 4;
1088 if (tbcount > 256)
1089 return (EINVAL);
1090 if (count == 8) {
1091 *tp++ = value;
1092 count = 0;
1093 }
1094 }
1095 break;
1096 }
1097 }
1098 done:
1099 if (cp >= end || tp >= eom)
1100 return (EMSGSIZE);
1101
1102 /*
1103 * bit length validation:
1104 * If a <length> is present, the number of digits in the <bit-data>
1105 * MUST be just sufficient to contain the number of bits specified
1106 * by the <length>. If there are insignificant bits in a final
1107 * hexadecimal or octal digit, they MUST be zero.
1108 * RFC2673, Section 3.2.
1109 */
1110 if (blen > 0) {
1111 int traillen;
1112
1113 if (((blen + 3) & ~3) != tbcount)
1114 return (EINVAL);
1115 traillen = tbcount - blen; /*%< between 0 and 3 */
1116 if (((value << (8 - traillen)) & 0xff) != 0)
1117 return (EINVAL);
1118 }
1119 else
1120 blen = tbcount;
1121 if (blen == 256)
1122 blen = 0;
1123
1124 /* encode the type and the significant bit fields */
1125 **labelp = DNS_LABELTYPE_BITSTRING;
1126 **dst = blen;
1127
1128 *bp = cp;
1129 *dst = tp;
1130
1131 return (0);
1132 }
1133
1134 static int
labellen(const u_char * lp)1135 labellen(const u_char *lp)
1136 {
1137 int bitlen;
1138 u_char l = *lp;
1139
1140 if ((l & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
1141 /* should be avoided by the caller */
1142 return (-1);
1143 }
1144
1145 if ((l & NS_CMPRSFLGS) == NS_TYPE_ELT) {
1146 if (l == DNS_LABELTYPE_BITSTRING) {
1147 if ((bitlen = *(lp + 1)) == 0)
1148 bitlen = 256;
1149 return ((bitlen + 7 ) / 8 + 1);
1150 }
1151 return (-1); /*%< unknwon ELT */
1152 }
1153 return (l);
1154 }
1155
1156 /*! \file */
1157