1 /* $NetBSD: ns_name.c,v 1.11 2014/03/07 01:07:01 christos Exp $ */
2
3 /*
4 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
5 * Copyright (c) 1996,1999 by Internet Software Consortium.
6 *
7 * Permission to use, copy, modify, and distribute this software for any
8 * purpose with or without fee is hereby granted, provided that the above
9 * copyright notice and this permission notice appear in all copies.
10 *
11 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
12 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
13 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
14 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
15 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
16 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
17 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18 */
19
20 #include <sys/cdefs.h>
21 #ifndef lint
22 #ifdef notdef
23 static const char rcsid[] = "Id: ns_name.c,v 1.11 2009/01/23 19:59:16 each Exp";
24 #else
25 __RCSID("$NetBSD: ns_name.c,v 1.11 2014/03/07 01:07:01 christos Exp $");
26 #endif
27 #endif
28
29 #include "port_before.h"
30
31 #include <sys/types.h>
32
33 #include <netinet/in.h>
34 #include <arpa/nameser.h>
35
36 #include <assert.h>
37 #include <errno.h>
38 #include <resolv.h>
39 #include <string.h>
40 #include <ctype.h>
41 #include <stdlib.h>
42 #include <limits.h>
43
44 #include "port_after.h"
45
46 #ifdef SPRINTF_CHAR
47 # define SPRINTF(x) ((int)strlen(sprintf/**/x))
48 #else
49 # define SPRINTF(x) (sprintf x)
50 #endif
51
52 #define NS_TYPE_ELT 0x40 /*%< EDNS0 extended label type */
53 #define DNS_LABELTYPE_BITSTRING 0x41
54
55 /* Data. */
56
57 static const char digits[] = "0123456789";
58
59 static const char digitvalue[256] = {
60 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*16*/
61 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*32*/
62 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*48*/
63 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -1, -1, -1, -1, -1, -1, /*64*/
64 -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*80*/
65 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*96*/
66 -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*112*/
67 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*128*/
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,
70 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
71 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
72 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
73 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
74 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
75 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*256*/
76 };
77
78 /* Forward. */
79
80 static int special(int);
81 static int printable(int);
82 static int dn_find(const u_char *, const u_char *,
83 const u_char * const *,
84 const u_char * const *);
85 static int encode_bitsring(const char **, const char *,
86 unsigned char **, unsigned char **,
87 unsigned const char *);
88 static int labellen(const u_char *);
89 static int decode_bitstring(const unsigned char **,
90 char *, const char *);
91
92 /* Public. */
93
94 /*%
95 * Convert an encoded domain name to printable ascii as per RFC1035.
96
97 * return:
98 *\li Number of bytes written to buffer, or -1 (with errno set)
99 *
100 * notes:
101 *\li The root is returned as "."
102 *\li All other domains are returned in non absolute form
103 */
104 int
ns_name_ntop(const u_char * src,char * dst,size_t dstsiz)105 ns_name_ntop(const u_char *src, char *dst, size_t dstsiz)
106 {
107 const u_char *cp;
108 char *dn, *eom;
109 u_char c;
110 u_int n;
111 int l;
112
113 cp = src;
114 dn = dst;
115 eom = dst + dstsiz;
116
117 while ((n = *cp++) != 0) {
118 if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
119 /* Some kind of compression pointer. */
120 errno = EMSGSIZE;
121 return (-1);
122 }
123 if (dn != dst) {
124 if (dn >= eom) {
125 errno = EMSGSIZE;
126 return (-1);
127 }
128 *dn++ = '.';
129 }
130 if ((l = labellen(cp - 1)) < 0) {
131 errno = EMSGSIZE; /*%< XXX */
132 return (-1);
133 }
134 if (dn + l >= eom) {
135 errno = EMSGSIZE;
136 return (-1);
137 }
138 if ((n & NS_CMPRSFLGS) == NS_TYPE_ELT) {
139 int m;
140
141 if (n != DNS_LABELTYPE_BITSTRING) {
142 /* XXX: labellen should reject this case */
143 errno = EINVAL;
144 return (-1);
145 }
146 if ((m = decode_bitstring(&cp, dn, eom)) < 0)
147 {
148 errno = EMSGSIZE;
149 return (-1);
150 }
151 dn += m;
152 continue;
153 }
154 for (; l > 0; l--) {
155 c = *cp++;
156 if (special(c)) {
157 if (dn + 1 >= eom) {
158 errno = EMSGSIZE;
159 return (-1);
160 }
161 *dn++ = '\\';
162 *dn++ = (char)c;
163 } else if (!printable(c)) {
164 if (dn + 3 >= eom) {
165 errno = EMSGSIZE;
166 return (-1);
167 }
168 *dn++ = '\\';
169 *dn++ = digits[c / 100];
170 *dn++ = digits[(c % 100) / 10];
171 *dn++ = digits[c % 10];
172 } else {
173 if (dn >= eom) {
174 errno = EMSGSIZE;
175 return (-1);
176 }
177 *dn++ = (char)c;
178 }
179 }
180 }
181 if (dn == dst) {
182 if (dn >= eom) {
183 errno = EMSGSIZE;
184 return (-1);
185 }
186 *dn++ = '.';
187 }
188 if (dn >= eom) {
189 errno = EMSGSIZE;
190 return (-1);
191 }
192 *dn++ = '\0';
193 _DIAGASSERT(__type_fit(int, dn - dst));
194 return (int)(dn - dst);
195 }
196
197 /*%
198 * Convert a ascii string into an encoded domain name as per RFC1035.
199 *
200 * return:
201 *
202 *\li -1 if it fails
203 *\li 1 if string was fully qualified
204 *\li 0 is string was not fully qualified
205 *
206 * notes:
207 *\li Enforces label and domain length limits.
208 */
209 int
ns_name_pton(const char * src,u_char * dst,size_t dstsiz)210 ns_name_pton(const char *src, u_char *dst, size_t dstsiz) {
211 return (ns_name_pton2(src, dst, dstsiz, NULL));
212 }
213
214 /*
215 * ns_name_pton2(src, dst, dstsiz, *dstlen)
216 * Convert a ascii string into an encoded domain name as per RFC1035.
217 * return:
218 * -1 if it fails
219 * 1 if string was fully qualified
220 * 0 is string was not fully qualified
221 * side effects:
222 * fills in *dstlen (if non-NULL)
223 * notes:
224 * Enforces label and domain length limits.
225 */
226 int
ns_name_pton2(const char * src,u_char * dst,size_t dstsiz,size_t * dstlen)227 ns_name_pton2(const char *src, u_char *dst, size_t dstsiz, size_t *dstlen) {
228 u_char *label, *bp, *eom;
229 int c, n, escaped, e = 0;
230 char *cp;
231
232 escaped = 0;
233 bp = dst;
234 eom = dst + dstsiz;
235 label = bp++;
236
237 while ((c = *src++) != 0) {
238 if (escaped) {
239 if (c == '[') { /*%< start a bit string label */
240 if ((cp = strchr(src, ']')) == NULL) {
241 errno = EINVAL; /*%< ??? */
242 return (-1);
243 }
244 if ((e = encode_bitsring(&src, cp + 2,
245 &label, &bp, eom))
246 != 0) {
247 errno = e;
248 return (-1);
249 }
250 escaped = 0;
251 label = bp++;
252 if ((c = *src++) == 0)
253 goto done;
254 else if (c != '.') {
255 errno = EINVAL;
256 return (-1);
257 }
258 continue;
259 }
260 else if ((cp = strchr(digits, c)) != NULL) {
261 n = (int)(cp - digits) * 100;
262 if ((c = *src++) == 0 ||
263 (cp = strchr(digits, c)) == NULL) {
264 errno = EMSGSIZE;
265 return (-1);
266 }
267 n += (int)(cp - digits) * 10;
268 if ((c = *src++) == 0 ||
269 (cp = strchr(digits, c)) == NULL) {
270 errno = EMSGSIZE;
271 return (-1);
272 }
273 n += (int)(cp - digits);
274 if (n > 255) {
275 errno = EMSGSIZE;
276 return (-1);
277 }
278 c = n;
279 }
280 escaped = 0;
281 } else if (c == '\\') {
282 escaped = 1;
283 continue;
284 } else if (c == '.') {
285 c = (int)(bp - label - 1);
286 if ((c & NS_CMPRSFLGS) != 0) { /*%< Label too big. */
287 errno = EMSGSIZE;
288 return (-1);
289 }
290 if (label >= eom) {
291 errno = EMSGSIZE;
292 return (-1);
293 }
294 *label = c;
295 /* Fully qualified ? */
296 if (*src == '\0') {
297 if (c != 0) {
298 if (bp >= eom) {
299 errno = EMSGSIZE;
300 return (-1);
301 }
302 *bp++ = '\0';
303 }
304 if ((bp - dst) > MAXCDNAME) {
305 errno = EMSGSIZE;
306 return (-1);
307 }
308 if (dstlen != NULL)
309 *dstlen = (bp - dst);
310 return (1);
311 }
312 if (c == 0 || *src == '.') {
313 errno = EMSGSIZE;
314 return (-1);
315 }
316 label = bp++;
317 continue;
318 }
319 if (bp >= eom) {
320 errno = EMSGSIZE;
321 return (-1);
322 }
323 *bp++ = (u_char)c;
324 }
325 c = (int)(bp - label - 1);
326 if ((c & NS_CMPRSFLGS) != 0) { /*%< Label too big. */
327 errno = EMSGSIZE;
328 return (-1);
329 }
330 done:
331 if (label >= eom) {
332 errno = EMSGSIZE;
333 return (-1);
334 }
335 *label = c;
336 if (c != 0) {
337 if (bp >= eom) {
338 errno = EMSGSIZE;
339 return (-1);
340 }
341 *bp++ = 0;
342 }
343 if ((bp - dst) > MAXCDNAME) { /*%< src too big */
344 errno = EMSGSIZE;
345 return (-1);
346 }
347 if (dstlen != NULL)
348 *dstlen = (bp - dst);
349 return (0);
350 }
351
352 /*%
353 * Convert a network strings labels into all lowercase.
354 *
355 * return:
356 *\li Number of bytes written to buffer, or -1 (with errno set)
357 *
358 * notes:
359 *\li Enforces label and domain length limits.
360 */
361
362 int
ns_name_ntol(const u_char * src,u_char * dst,size_t dstsiz)363 ns_name_ntol(const u_char *src, u_char *dst, size_t dstsiz)
364 {
365 const u_char *cp;
366 u_char *dn, *eom;
367 u_char c;
368 u_int n;
369 int l;
370
371 cp = src;
372 dn = dst;
373 eom = dst + dstsiz;
374
375 if (dn >= eom) {
376 errno = EMSGSIZE;
377 return (-1);
378 }
379 while ((n = *cp++) != 0) {
380 if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
381 /* Some kind of compression pointer. */
382 errno = EMSGSIZE;
383 return (-1);
384 }
385 *dn++ = n;
386 if ((l = labellen(cp - 1)) < 0) {
387 errno = EMSGSIZE;
388 return (-1);
389 }
390 if (dn + l >= eom) {
391 errno = EMSGSIZE;
392 return (-1);
393 }
394 for (; l > 0; l--) {
395 c = *cp++;
396 if (isascii(c) && isupper(c))
397 *dn++ = tolower(c);
398 else
399 *dn++ = c;
400 }
401 }
402 *dn++ = '\0';
403 _DIAGASSERT(__type_fit(int, dn - dst));
404 return (int)(dn - dst);
405 }
406
407 /*%
408 * Unpack a domain name from a message, source may be compressed.
409 *
410 * return:
411 *\li -1 if it fails, or consumed octets if it succeeds.
412 */
413 int
ns_name_unpack(const u_char * msg,const u_char * eom,const u_char * src,u_char * dst,size_t dstsiz)414 ns_name_unpack(const u_char *msg, const u_char *eom, const u_char *src,
415 u_char *dst, size_t dstsiz)
416 {
417 return (ns_name_unpack2(msg, eom, src, dst, dstsiz, NULL));
418 }
419
420 /*
421 * ns_name_unpack2(msg, eom, src, dst, dstsiz, *dstlen)
422 * Unpack a domain name from a message, source may be compressed.
423 * return:
424 * -1 if it fails, or consumed octets if it succeeds.
425 * side effect:
426 * fills in *dstlen (if non-NULL).
427 */
428 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)429 ns_name_unpack2(const u_char *msg, const u_char *eom, const u_char *src,
430 u_char *dst, size_t dstsiz, size_t *dstlen)
431 {
432 const u_char *srcp, *dstlim;
433 u_char *dstp;
434 int n, len, checked, l;
435
436 len = -1;
437 checked = 0;
438 dstp = dst;
439 srcp = src;
440 dstlim = dst + dstsiz;
441 if (srcp < msg || srcp >= eom) {
442 errno = EMSGSIZE;
443 return (-1);
444 }
445 /* Fetch next label in domain name. */
446 while ((n = *srcp++) != 0) {
447 /* Check for indirection. */
448 switch (n & NS_CMPRSFLGS) {
449 case 0:
450 case NS_TYPE_ELT:
451 /* Limit checks. */
452 if ((l = labellen(srcp - 1)) < 0) {
453 errno = EMSGSIZE;
454 return (-1);
455 }
456 if (dstp + l + 1 >= dstlim || srcp + l >= eom) {
457 errno = EMSGSIZE;
458 return (-1);
459 }
460 checked += l + 1;
461 *dstp++ = n;
462 memcpy(dstp, srcp, (size_t)l);
463 dstp += l;
464 srcp += l;
465 break;
466
467 case NS_CMPRSFLGS:
468 if (srcp >= eom) {
469 errno = EMSGSIZE;
470 return (-1);
471 }
472 if (len < 0) {
473 _DIAGASSERT(__type_fit(int, srcp - src + 1));
474 len = (int)(srcp - src + 1);
475 }
476 n = ((n & 0x3f) << 8) | (*srcp & 0xff);
477 if (n >= eom - msg) { /*%< Out of range. */
478 errno = EMSGSIZE;
479 return (-1);
480 }
481 srcp = msg + n;
482 checked += 2;
483 /*
484 * Check for loops in the compressed name;
485 * if we've looked at the whole message,
486 * there must be a loop.
487 */
488 if (checked >= eom - msg) {
489 errno = EMSGSIZE;
490 return (-1);
491 }
492 break;
493
494 default:
495 errno = EMSGSIZE;
496 return (-1); /*%< flag error */
497 }
498 }
499 *dstp++ = 0;
500 if (dstlen != NULL)
501 *dstlen = dstp - dst;
502 if (len < 0) {
503 _DIAGASSERT(__type_fit(int, srcp - src));
504 len = (int)(srcp - src);
505 }
506 return len;
507 }
508
509 /*%
510 * Pack domain name 'domain' into 'comp_dn'.
511 *
512 * return:
513 *\li Size of the compressed name, or -1.
514 *
515 * notes:
516 *\li 'dnptrs' is an array of pointers to previous compressed names.
517 *\li dnptrs[0] is a pointer to the beginning of the message. The array
518 * ends with NULL.
519 *\li 'lastdnptr' is a pointer to the end of the array pointed to
520 * by 'dnptrs'.
521 *
522 * Side effects:
523 *\li The list of pointers in dnptrs is updated for labels inserted into
524 * the message as we compress the name. If 'dnptr' is NULL, we don't
525 * try to compress names. If 'lastdnptr' is NULL, we don't update the
526 * list.
527 */
528 int
ns_name_pack(const u_char * src,u_char * dst,int dstsiz,const u_char ** dnptrs,const u_char ** lastdnptr)529 ns_name_pack(const u_char *src, u_char *dst, int dstsiz,
530 const u_char **dnptrs, const u_char **lastdnptr)
531 {
532 u_char *dstp;
533 const u_char **cpp, **lpp, *eob, *msg;
534 const u_char *srcp;
535 int n, l, first = 1;
536
537 srcp = src;
538 dstp = dst;
539 eob = dstp + dstsiz;
540 lpp = cpp = NULL;
541 if (dnptrs != NULL) {
542 if ((msg = *dnptrs++) != NULL) {
543 for (cpp = dnptrs; *cpp != NULL; cpp++)
544 continue;
545 lpp = cpp; /*%< end of list to search */
546 }
547 } else
548 msg = NULL;
549
550 /* make sure the domain we are about to add is legal */
551 l = 0;
552 do {
553 int l0;
554
555 n = *srcp;
556 if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
557 errno = EMSGSIZE;
558 return (-1);
559 }
560 if ((l0 = labellen(srcp)) < 0) {
561 errno = EINVAL;
562 return (-1);
563 }
564 l += l0 + 1;
565 if (l > MAXCDNAME) {
566 errno = EMSGSIZE;
567 return (-1);
568 }
569 srcp += l0 + 1;
570 } while (n != 0);
571
572 /* from here on we need to reset compression pointer array on error */
573 srcp = src;
574 do {
575 /* Look to see if we can use pointers. */
576 n = *srcp;
577 if (n != 0 && msg != NULL) {
578 l = dn_find(srcp, msg, (const u_char * const *)dnptrs,
579 (const u_char * const *)lpp);
580 if (l >= 0) {
581 if (dstp + 1 >= eob) {
582 goto cleanup;
583 }
584 *dstp++ = ((u_int32_t)l >> 8) | NS_CMPRSFLGS;
585 *dstp++ = l % 256;
586 _DIAGASSERT(__type_fit(int, dstp - dst));
587 return (int)(dstp - dst);
588 }
589 /* Not found, save it. */
590 if (lastdnptr != NULL && cpp < lastdnptr - 1 &&
591 (dstp - msg) < 0x4000 && first) {
592 *cpp++ = dstp;
593 *cpp = NULL;
594 first = 0;
595 }
596 }
597 /* copy label to buffer */
598 if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
599 /* Should not happen. */
600 goto cleanup;
601 }
602 n = labellen(srcp);
603 if (dstp + 1 + n >= eob) {
604 goto cleanup;
605 }
606 memcpy(dstp, srcp, (size_t)(n + 1));
607 srcp += n + 1;
608 dstp += n + 1;
609 } while (n != 0);
610
611 if (dstp > eob) {
612 cleanup:
613 if (msg != NULL)
614 *lpp = NULL;
615 errno = EMSGSIZE;
616 return (-1);
617 }
618 _DIAGASSERT(__type_fit(int, dstp - dst));
619 return (int)(dstp - dst);
620 }
621
622 /*%
623 * Expand compressed domain name to presentation format.
624 *
625 * return:
626 *\li Number of bytes read out of `src', or -1 (with errno set).
627 *
628 * note:
629 *\li Root domain returns as "." not "".
630 */
631 int
ns_name_uncompress(const u_char * msg,const u_char * eom,const u_char * src,char * dst,size_t dstsiz)632 ns_name_uncompress(const u_char *msg, const u_char *eom, const u_char *src,
633 char *dst, size_t dstsiz)
634 {
635 u_char tmp[NS_MAXCDNAME];
636 int n;
637
638 if ((n = ns_name_unpack(msg, eom, src, tmp, sizeof tmp)) == -1)
639 return (-1);
640 if (ns_name_ntop(tmp, dst, dstsiz) == -1)
641 return (-1);
642 return (n);
643 }
644
645 /*%
646 * Compress a domain name into wire format, using compression pointers.
647 *
648 * return:
649 *\li Number of bytes consumed in `dst' or -1 (with errno set).
650 *
651 * notes:
652 *\li 'dnptrs' is an array of pointers to previous compressed names.
653 *\li dnptrs[0] is a pointer to the beginning of the message.
654 *\li The list ends with NULL. 'lastdnptr' is a pointer to the end of the
655 * array pointed to by 'dnptrs'. Side effect is to update the list of
656 * pointers for labels inserted into the message as we compress the name.
657 *\li If 'dnptr' is NULL, we don't try to compress names. If 'lastdnptr'
658 * is NULL, we don't update the list.
659 */
660 int
ns_name_compress(const char * src,u_char * dst,size_t dstsiz,const u_char ** dnptrs,const u_char ** lastdnptr)661 ns_name_compress(const char *src, u_char *dst, size_t dstsiz,
662 const u_char **dnptrs, const u_char **lastdnptr)
663 {
664 u_char tmp[NS_MAXCDNAME];
665
666 if (ns_name_pton(src, tmp, sizeof tmp) == -1)
667 return (-1);
668 return (ns_name_pack(tmp, dst, (int)dstsiz, dnptrs, lastdnptr));
669 }
670
671 /*%
672 * Reset dnptrs so that there are no active references to pointers at or
673 * after src.
674 */
675 void
ns_name_rollback(const u_char * src,const u_char ** dnptrs,const u_char ** lastdnptr)676 ns_name_rollback(const u_char *src, const u_char **dnptrs,
677 const u_char **lastdnptr)
678 {
679 while (dnptrs < lastdnptr && *dnptrs != NULL) {
680 if (*dnptrs >= src) {
681 *dnptrs = NULL;
682 break;
683 }
684 dnptrs++;
685 }
686 }
687
688 /*%
689 * Advance *ptrptr to skip over the compressed name it points at.
690 *
691 * return:
692 *\li 0 on success, -1 (with errno set) on failure.
693 */
694 int
ns_name_skip(const u_char ** ptrptr,const u_char * eom)695 ns_name_skip(const u_char **ptrptr, const u_char *eom)
696 {
697 const u_char *cp;
698 u_int n;
699 int l;
700
701 cp = *ptrptr;
702 while (cp < eom && (n = *cp++) != 0) {
703 /* Check for indirection. */
704 switch (n & NS_CMPRSFLGS) {
705 case 0: /*%< normal case, n == len */
706 cp += n;
707 continue;
708 case NS_TYPE_ELT: /*%< EDNS0 extended label */
709 if ((l = labellen(cp - 1)) < 0) {
710 errno = EMSGSIZE; /*%< XXX */
711 return (-1);
712 }
713 cp += l;
714 continue;
715 case NS_CMPRSFLGS: /*%< indirection */
716 cp++;
717 break;
718 default: /*%< illegal type */
719 errno = EMSGSIZE;
720 return (-1);
721 }
722 break;
723 }
724 if (cp > eom) {
725 errno = EMSGSIZE;
726 return (-1);
727 }
728 *ptrptr = cp;
729 return (0);
730 }
731
732 /* Find the number of octets an nname takes up, including the root label.
733 * (This is basically ns_name_skip() without compression-pointer support.)
734 * ((NOTE: can only return zero if passed-in namesiz argument is zero.))
735 */
736 ssize_t
ns_name_length(ns_nname_ct nname,size_t namesiz)737 ns_name_length(ns_nname_ct nname, size_t namesiz) {
738 ns_nname_ct orig = nname;
739 u_int n;
740
741 while (namesiz-- > 0 && (n = *nname++) != 0) {
742 if ((n & NS_CMPRSFLGS) != 0) {
743 errno = EISDIR;
744 return (-1);
745 }
746 if (n > namesiz) {
747 errno = EMSGSIZE;
748 return (-1);
749 }
750 nname += n;
751 namesiz -= n;
752 }
753 return (nname - orig);
754 }
755
756 /* Compare two nname's for equality. Return -1 on error (setting errno).
757 */
758 int
ns_name_eq(ns_nname_ct a,size_t as,ns_nname_ct b,size_t bs)759 ns_name_eq(ns_nname_ct a, size_t as, ns_nname_ct b, size_t bs) {
760 ns_nname_ct ae = a + as, be = b + bs;
761 int ac, bc;
762
763 while (ac = *a, bc = *b, ac != 0 && bc != 0) {
764 if ((ac & NS_CMPRSFLGS) != 0 || (bc & NS_CMPRSFLGS) != 0) {
765 errno = EISDIR;
766 return (-1);
767 }
768 if (a + ac >= ae || b + bc >= be) {
769 errno = EMSGSIZE;
770 return (-1);
771 }
772 if (ac != bc || strncasecmp((const char *) ++a,
773 (const char *) ++b,
774 (size_t)ac) != 0)
775 return (0);
776 a += ac, b += bc;
777 }
778 return (ac == 0 && bc == 0);
779 }
780
781 /* Is domain "A" owned by (at or below) domain "B"?
782 */
783 int
ns_name_owned(ns_namemap_ct a,int an,ns_namemap_ct b,int bn)784 ns_name_owned(ns_namemap_ct a, int an, ns_namemap_ct b, int bn) {
785 /* If A is shorter, it cannot be owned by B. */
786 if (an < bn)
787 return (0);
788
789 /* If they are unequal before the length of the shorter, A cannot... */
790 while (bn > 0) {
791 if (a->len != b->len ||
792 strncasecmp((const char *) a->base,
793 (const char *) b->base, (size_t)a->len) != 0)
794 return (0);
795 a++, an--;
796 b++, bn--;
797 }
798
799 /* A might be longer or not, but either way, B owns it. */
800 return (1);
801 }
802
803 /* Build an array of <base,len> tuples from an nname, top-down order.
804 * Return the number of tuples (labels) thus discovered.
805 */
806 int
ns_name_map(ns_nname_ct nname,size_t namelen,ns_namemap_t map,int mapsize)807 ns_name_map(ns_nname_ct nname, size_t namelen, ns_namemap_t map, int mapsize) {
808 u_int n;
809 int l;
810
811 n = *nname++;
812 namelen--;
813
814 /* Root zone? */
815 if (n == 0) {
816 /* Extra data follows name? */
817 if (namelen > 0) {
818 errno = EMSGSIZE;
819 return (-1);
820 }
821 return (0);
822 }
823
824 /* Compression pointer? */
825 if ((n & NS_CMPRSFLGS) != 0) {
826 errno = EISDIR;
827 return (-1);
828 }
829
830 /* Label too long? */
831 if (n > namelen) {
832 errno = EMSGSIZE;
833 return (-1);
834 }
835
836 /* Recurse to get rest of name done first. */
837 l = ns_name_map(nname + n, namelen - n, map, mapsize);
838 if (l < 0)
839 return (-1);
840
841 /* Too many labels? */
842 if (l >= mapsize) {
843 errno = ENAMETOOLONG;
844 return (-1);
845 }
846
847 /* We're on our way back up-stack, store current map data. */
848 map[l].base = nname;
849 map[l].len = n;
850 return (l + 1);
851 }
852
853 /* Count the labels in a domain name. Root counts, so COM. has two. This
854 * is to make the result comparable to the result of ns_name_map().
855 */
856 int
ns_name_labels(ns_nname_ct nname,size_t namesiz)857 ns_name_labels(ns_nname_ct nname, size_t namesiz) {
858 int ret = 0;
859 u_int n;
860
861 while (namesiz-- > 0 && (n = *nname++) != 0) {
862 if ((n & NS_CMPRSFLGS) != 0) {
863 errno = EISDIR;
864 return (-1);
865 }
866 if (n > namesiz) {
867 errno = EMSGSIZE;
868 return (-1);
869 }
870 nname += n;
871 namesiz -= n;
872 ret++;
873 }
874 return (ret + 1);
875 }
876
877 /* Private. */
878
879 /*%
880 * Thinking in noninternationalized USASCII (per the DNS spec),
881 * is this characted special ("in need of quoting") ?
882 *
883 * return:
884 *\li boolean.
885 */
886 static int
special(int ch)887 special(int ch) {
888 switch (ch) {
889 case 0x22: /*%< '"' */
890 case 0x2E: /*%< '.' */
891 case 0x3B: /*%< ';' */
892 case 0x5C: /*%< '\\' */
893 case 0x28: /*%< '(' */
894 case 0x29: /*%< ')' */
895 /* Special modifiers in zone files. */
896 case 0x40: /*%< '@' */
897 case 0x24: /*%< '$' */
898 return (1);
899 default:
900 return (0);
901 }
902 }
903
904 /*%
905 * Thinking in noninternationalized USASCII (per the DNS spec),
906 * is this character visible and not a space when printed ?
907 *
908 * return:
909 *\li boolean.
910 */
911 static int
printable(int ch)912 printable(int ch) {
913 return (ch > 0x20 && ch < 0x7f);
914 }
915
916 /*%
917 * Thinking in noninternationalized USASCII (per the DNS spec),
918 * convert this character to lower case if it's upper case.
919 */
920 static int
mklower(int ch)921 mklower(int ch) {
922 if (ch >= 0x41 && ch <= 0x5A)
923 return (ch + 0x20);
924 return (ch);
925 }
926
927 /*%
928 * Search for the counted-label name in an array of compressed names.
929 *
930 * return:
931 *\li offset from msg if found, or -1.
932 *
933 * notes:
934 *\li dnptrs is the pointer to the first name on the list,
935 *\li not the pointer to the start of the message.
936 */
937 static int
dn_find(const u_char * domain,const u_char * msg,const u_char * const * dnptrs,const u_char * const * lastdnptr)938 dn_find(const u_char *domain, const u_char *msg,
939 const u_char * const *dnptrs,
940 const u_char * const *lastdnptr)
941 {
942 const u_char *dn, *cp, *sp;
943 const u_char * const *cpp;
944 u_int n;
945
946 for (cpp = dnptrs; cpp < lastdnptr; cpp++) {
947 sp = *cpp;
948 /*
949 * terminate search on:
950 * root label
951 * compression pointer
952 * unusable offset
953 */
954 while (*sp != 0 && (*sp & NS_CMPRSFLGS) == 0 &&
955 (sp - msg) < 0x4000) {
956 dn = domain;
957 cp = sp;
958 while ((n = *cp++) != 0) {
959 /*
960 * check for indirection
961 */
962 switch (n & NS_CMPRSFLGS) {
963 case 0: /*%< normal case, n == len */
964 n = labellen(cp - 1); /*%< XXX */
965 if (n != *dn++)
966 goto next;
967
968 for (; n > 0; n--)
969 if (mklower(*dn++) !=
970 mklower(*cp++))
971 goto next;
972 /* Is next root for both ? */
973 if (*dn == '\0' && *cp == '\0') {
974 _DIAGASSERT(__type_fit(int,
975 sp - msg));
976 return (int)(sp - msg);
977 }
978 if (*dn)
979 continue;
980 goto next;
981 case NS_CMPRSFLGS: /*%< indirection */
982 cp = msg + (((n & 0x3f) << 8) | *cp);
983 break;
984
985 default: /*%< illegal type */
986 errno = EMSGSIZE;
987 return (-1);
988 }
989 }
990 next: ;
991 sp += *sp + 1;
992 }
993 }
994 errno = ENOENT;
995 return (-1);
996 }
997
998 static int
decode_bitstring(const unsigned char ** cpp,char * dn,const char * eom)999 decode_bitstring(const unsigned char **cpp, char *dn, const char *eom)
1000 {
1001 const unsigned char *cp = *cpp;
1002 char *beg = dn, tc;
1003 int b, blen, plen, i;
1004
1005 if ((blen = (*cp & 0xff)) == 0)
1006 blen = 256;
1007 plen = (blen + 3) / 4;
1008 plen += (int)sizeof("\\[x/]") + (blen > 99 ? 3 : (blen > 9) ? 2 : 1);
1009 if (dn + plen >= eom)
1010 return (-1);
1011
1012 cp++;
1013 i = SPRINTF((dn, "\\[x"));
1014 if (i < 0)
1015 return (-1);
1016 dn += i;
1017 for (b = blen; b > 7; b -= 8, cp++) {
1018 i = SPRINTF((dn, "%02x", *cp & 0xff));
1019 if (i < 0)
1020 return (-1);
1021 dn += i;
1022 }
1023 if (b > 4) {
1024 tc = *cp++;
1025 i = SPRINTF((dn, "%02x", tc & (0xff << (8 - b))));
1026 if (i < 0)
1027 return (-1);
1028 dn += i;
1029 } else if (b > 0) {
1030 tc = *cp++;
1031 i = SPRINTF((dn, "%1x",
1032 (((u_int32_t)tc >> 4) & 0x0f) & (0x0f << (4 - b))));
1033 if (i < 0)
1034 return (-1);
1035 dn += i;
1036 }
1037 i = SPRINTF((dn, "/%d]", blen));
1038 if (i < 0)
1039 return (-1);
1040 dn += i;
1041
1042 *cpp = cp;
1043 _DIAGASSERT(__type_fit(int, dn - beg));
1044 return (int)(dn - beg);
1045 }
1046
1047 static int
encode_bitsring(const char ** bp,const char * end,unsigned char ** labelp,unsigned char ** dst,unsigned const char * eom)1048 encode_bitsring(const char **bp, const char *end, unsigned char **labelp,
1049 unsigned char ** dst, unsigned const char *eom)
1050 {
1051 int afterslash = 0;
1052 const char *cp = *bp;
1053 unsigned char *tp;
1054 char c;
1055 const char *beg_blen;
1056 char *end_blen = NULL;
1057 int value = 0, count = 0, tbcount = 0, blen = 0;
1058
1059 beg_blen = end_blen = NULL;
1060
1061 /* a bitstring must contain at least 2 characters */
1062 if (end - cp < 2)
1063 return (EINVAL);
1064
1065 /* XXX: currently, only hex strings are supported */
1066 if (*cp++ != 'x')
1067 return (EINVAL);
1068 if (!isxdigit((*cp) & 0xff)) /*%< reject '\[x/BLEN]' */
1069 return (EINVAL);
1070
1071 for (tp = *dst + 1; cp < end && tp < eom; cp++) {
1072 switch((c = *cp)) {
1073 case ']': /*%< end of the bitstring */
1074 if (afterslash) {
1075 if (beg_blen == NULL)
1076 return (EINVAL);
1077 blen = (int)strtol(beg_blen, &end_blen, 10);
1078 if (*end_blen != ']')
1079 return (EINVAL);
1080 }
1081 if (count)
1082 *tp++ = ((value << 4) & 0xff);
1083 cp++; /*%< skip ']' */
1084 goto done;
1085 case '/':
1086 afterslash = 1;
1087 break;
1088 default:
1089 if (afterslash) {
1090 if (!isdigit(c&0xff))
1091 return (EINVAL);
1092 if (beg_blen == NULL) {
1093
1094 if (c == '0') {
1095 /* blen never begings with 0 */
1096 return (EINVAL);
1097 }
1098 beg_blen = cp;
1099 }
1100 } else {
1101 if (!isxdigit(c&0xff))
1102 return (EINVAL);
1103 value <<= 4;
1104 value += digitvalue[(int)c];
1105 count += 4;
1106 tbcount += 4;
1107 if (tbcount > 256)
1108 return (EINVAL);
1109 if (count == 8) {
1110 *tp++ = value;
1111 count = 0;
1112 }
1113 }
1114 break;
1115 }
1116 }
1117 done:
1118 if (cp >= end || tp >= eom)
1119 return (EMSGSIZE);
1120
1121 /*
1122 * bit length validation:
1123 * If a <length> is present, the number of digits in the <bit-data>
1124 * MUST be just sufficient to contain the number of bits specified
1125 * by the <length>. If there are insignificant bits in a final
1126 * hexadecimal or octal digit, they MUST be zero.
1127 * RFC2673, Section 3.2.
1128 */
1129 if (blen > 0) {
1130 int traillen;
1131
1132 if (((blen + 3) & ~3) != tbcount)
1133 return (EINVAL);
1134 traillen = tbcount - blen; /*%< between 0 and 3 */
1135 if (((value << (8 - traillen)) & 0xff) != 0)
1136 return (EINVAL);
1137 }
1138 else
1139 blen = tbcount;
1140 if (blen == 256)
1141 blen = 0;
1142
1143 /* encode the type and the significant bit fields */
1144 **labelp = DNS_LABELTYPE_BITSTRING;
1145 **dst = blen;
1146
1147 *bp = cp;
1148 *dst = tp;
1149
1150 return (0);
1151 }
1152
1153 static int
labellen(const u_char * lp)1154 labellen(const u_char *lp)
1155 {
1156 int bitlen;
1157 u_char l = *lp;
1158
1159 if ((l & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
1160 /* should be avoided by the caller */
1161 return (-1);
1162 }
1163
1164 if ((l & NS_CMPRSFLGS) == NS_TYPE_ELT) {
1165 if (l == DNS_LABELTYPE_BITSTRING) {
1166 if ((bitlen = *(lp + 1)) == 0)
1167 bitlen = 256;
1168 return ((bitlen + 7 ) / 8 + 1);
1169 }
1170 return (-1); /*%< unknwon ELT */
1171 }
1172 return (l);
1173 }
1174
1175 /*! \file */
1176