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