2 * SPDX-License-Identifier: ISC
4 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
5 * Copyright (c) 1996,1999 by Internet Software Consortium.
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.
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.
21 static const char rcsid[] = "$Id: ns_name.c,v 1.11 2009/01/23 19:59:16 each Exp $";
23 #include <sys/cdefs.h>
24 __FBSDID("$FreeBSD$");
26 #include "port_before.h"
28 #include <sys/types.h>
30 #include <netinet/in.h>
31 #include <arpa/nameser.h>
40 #include "port_after.h"
43 # define SPRINTF(x) strlen(sprintf/**/x)
45 # define SPRINTF(x) ((size_t)sprintf x)
48 #define NS_TYPE_ELT 0x40 /*%< EDNS0 extended label type */
49 #define DNS_LABELTYPE_BITSTRING 0x41
53 static const char digits[] = "0123456789";
55 static const char digitvalue[256] = {
56 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*16*/
57 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*32*/
58 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*48*/
59 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -1, -1, -1, -1, -1, -1, /*64*/
60 -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*80*/
61 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*96*/
62 -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*112*/
63 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*128*/
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,
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, /*256*/
76 static int special(int);
77 static int printable(int);
78 static int dn_find(const u_char *, const u_char *,
79 const u_char * const *,
80 const u_char * const *);
81 static int encode_bitsring(const char **, const char *,
82 unsigned char **, unsigned char **,
83 unsigned const char *);
84 static int labellen(const u_char *);
85 static int decode_bitstring(const unsigned char **,
86 char *, const char *);
91 * Convert an encoded domain name to printable ascii as per RFC1035.
94 *\li Number of bytes written to buffer, or -1 (with errno set)
97 *\li The root is returned as "."
98 *\li All other domains are returned in non absolute form
101 ns_name_ntop(const u_char *src, char *dst, size_t dstsiz)
113 while ((n = *cp++) != 0) {
114 if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
115 /* Some kind of compression pointer. */
126 if ((l = labellen(cp - 1)) < 0) {
127 errno = EMSGSIZE; /*%< XXX */
134 if ((n & NS_CMPRSFLGS) == NS_TYPE_ELT) {
137 if (n != DNS_LABELTYPE_BITSTRING) {
138 /* XXX: labellen should reject this case */
142 if ((m = decode_bitstring(&cp, dn, eom)) < 0)
150 for ((void)NULL; l > 0; l--) {
159 } else if (!printable(c)) {
165 *dn++ = digits[c / 100];
166 *dn++ = digits[(c % 100) / 10];
167 *dn++ = digits[c % 10];
193 * Convert a ascii string into an encoded domain name as per RFC1035.
198 *\li 1 if string was fully qualified
199 *\li 0 is string was not fully qualified
202 *\li Enforces label and domain length limits.
205 ns_name_pton(const char *src, u_char *dst, size_t dstsiz) {
206 return (ns_name_pton2(src, dst, dstsiz, NULL));
210 * ns_name_pton2(src, dst, dstsiz, *dstlen)
211 * Convert a ascii string into an encoded domain name as per RFC1035.
214 * 1 if string was fully qualified
215 * 0 is string was not fully qualified
217 * fills in *dstlen (if non-NULL)
219 * Enforces label and domain length limits.
222 ns_name_pton2(const char *src, u_char *dst, size_t dstsiz, size_t *dstlen) {
223 u_char *label, *bp, *eom;
224 int c, n, escaped, e = 0;
232 while ((c = *src++) != 0) {
234 if (c == '[') { /*%< start a bit string label */
235 if ((cp = strchr(src, ']')) == NULL) {
236 errno = EINVAL; /*%< ??? */
239 if ((e = encode_bitsring(&src, cp + 2,
247 if ((c = *src++) == 0)
255 else if ((cp = strchr(digits, c)) != NULL) {
256 n = (cp - digits) * 100;
257 if ((c = *src++) == 0 ||
258 (cp = strchr(digits, c)) == NULL) {
262 n += (cp - digits) * 10;
263 if ((c = *src++) == 0 ||
264 (cp = strchr(digits, c)) == NULL) {
276 } else if (c == '\\') {
279 } else if (c == '.') {
280 c = (bp - label - 1);
281 if ((c & NS_CMPRSFLGS) != 0) { /*%< Label too big. */
290 /* Fully qualified ? */
299 if ((bp - dst) > MAXCDNAME) {
304 *dstlen = (bp - dst);
307 if (c == 0 || *src == '.') {
320 c = (bp - label - 1);
321 if ((c & NS_CMPRSFLGS) != 0) { /*%< Label too big. */
338 if ((bp - dst) > MAXCDNAME) { /*%< src too big */
343 *dstlen = (bp - dst);
348 * Convert a network strings labels into all lowercase.
351 *\li Number of bytes written to buffer, or -1 (with errno set)
354 *\li Enforces label and domain length limits.
358 ns_name_ntol(const u_char *src, u_char *dst, size_t dstsiz)
374 while ((n = *cp++) != 0) {
375 if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
376 /* Some kind of compression pointer. */
381 if ((l = labellen(cp - 1)) < 0) {
389 for ((void)NULL; l > 0; l--) {
391 if (isascii(c) && isupper(c))
402 * Unpack a domain name from a message, source may be compressed.
405 *\li -1 if it fails, or consumed octets if it succeeds.
408 ns_name_unpack(const u_char *msg, const u_char *eom, const u_char *src,
409 u_char *dst, size_t dstsiz)
411 return (ns_name_unpack2(msg, eom, src, dst, dstsiz, NULL));
415 * ns_name_unpack2(msg, eom, src, dst, dstsiz, *dstlen)
416 * Unpack a domain name from a message, source may be compressed.
418 * -1 if it fails, or consumed octets if it succeeds.
420 * fills in *dstlen (if non-NULL).
423 ns_name_unpack2(const u_char *msg, const u_char *eom, const u_char *src,
424 u_char *dst, size_t dstsiz, size_t *dstlen)
426 const u_char *srcp, *dstlim;
428 int n, len, checked, l;
434 dstlim = dst + dstsiz;
435 if (srcp < msg || srcp >= eom) {
439 /* Fetch next label in domain name. */
440 while ((n = *srcp++) != 0) {
441 /* Check for indirection. */
442 switch (n & NS_CMPRSFLGS) {
446 if ((l = labellen(srcp - 1)) < 0) {
450 if (dstp + l + 1 >= dstlim || srcp + l >= eom) {
456 memcpy(dstp, srcp, l);
467 len = srcp - src + 1;
468 l = ((n & 0x3f) << 8) | (*srcp & 0xff);
469 if (l >= eom - msg) { /*%< Out of range. */
476 * Check for loops in the compressed name;
477 * if we've looked at the whole message,
478 * there must be a loop.
480 if (checked >= eom - msg) {
488 return (-1); /*%< flag error */
493 *dstlen = dstp - dst;
500 * Pack domain name 'domain' into 'comp_dn'.
503 *\li Size of the compressed name, or -1.
506 *\li 'dnptrs' is an array of pointers to previous compressed names.
507 *\li dnptrs[0] is a pointer to the beginning of the message. The array
509 *\li 'lastdnptr' is a pointer to the end of the array pointed to
513 *\li The list of pointers in dnptrs is updated for labels inserted into
514 * the message as we compress the name. If 'dnptr' is NULL, we don't
515 * try to compress names. If 'lastdnptr' is NULL, we don't update the
519 ns_name_pack(const u_char *src, u_char *dst, int dstsiz,
520 const u_char **dnptrs, const u_char **lastdnptr)
523 const u_char **cpp, **lpp, *eob, *msg;
531 if (dnptrs != NULL) {
532 if ((msg = *dnptrs++) != NULL) {
533 for (cpp = dnptrs; *cpp != NULL; cpp++)
535 lpp = cpp; /*%< end of list to search */
540 /* make sure the domain we are about to add is legal */
546 if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
550 if ((l0 = labellen(srcp)) < 0) {
562 /* from here on we need to reset compression pointer array on error */
565 /* Look to see if we can use pointers. */
567 if (n != 0 && msg != NULL) {
568 l = dn_find(srcp, msg, (const u_char * const *)dnptrs,
569 (const u_char * const *)lpp);
571 if (dstp + 1 >= eob) {
574 *dstp++ = (l >> 8) | NS_CMPRSFLGS;
578 /* Not found, save it. */
579 if (lastdnptr != NULL && cpp < lastdnptr - 1 &&
580 (dstp - msg) < 0x4000 && first) {
586 /* copy label to buffer */
587 if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
588 /* Should not happen. */
592 if (dstp + 1 + n >= eob) {
595 memcpy(dstp, srcp, n + 1);
611 * Expand compressed domain name to presentation format.
614 *\li Number of bytes read out of `src', or -1 (with errno set).
617 *\li Root domain returns as "." not "".
620 ns_name_uncompress(const u_char *msg, const u_char *eom, const u_char *src,
621 char *dst, size_t dstsiz)
623 u_char tmp[NS_MAXCDNAME];
626 if ((n = ns_name_unpack(msg, eom, src, tmp, sizeof tmp)) == -1)
628 if (ns_name_ntop(tmp, dst, dstsiz) == -1)
634 * Compress a domain name into wire format, using compression pointers.
637 *\li Number of bytes consumed in `dst' or -1 (with errno set).
640 *\li 'dnptrs' is an array of pointers to previous compressed names.
641 *\li dnptrs[0] is a pointer to the beginning of the message.
642 *\li The list ends with NULL. 'lastdnptr' is a pointer to the end of the
643 * array pointed to by 'dnptrs'. Side effect is to update the list of
644 * pointers for labels inserted into the message as we compress the name.
645 *\li If 'dnptr' is NULL, we don't try to compress names. If 'lastdnptr'
646 * is NULL, we don't update the list.
649 ns_name_compress(const char *src, u_char *dst, size_t dstsiz,
650 const u_char **dnptrs, const u_char **lastdnptr)
652 u_char tmp[NS_MAXCDNAME];
654 if (ns_name_pton(src, tmp, sizeof tmp) == -1)
656 return (ns_name_pack(tmp, dst, dstsiz, dnptrs, lastdnptr));
660 * Reset dnptrs so that there are no active references to pointers at or
664 ns_name_rollback(const u_char *src, const u_char **dnptrs,
665 const u_char **lastdnptr)
667 while (dnptrs < lastdnptr && *dnptrs != NULL) {
668 if (*dnptrs >= src) {
677 * Advance *ptrptr to skip over the compressed name it points at.
680 *\li 0 on success, -1 (with errno set) on failure.
683 ns_name_skip(const u_char **ptrptr, const u_char *eom)
690 while (cp < eom && (n = *cp++) != 0) {
691 /* Check for indirection. */
692 switch (n & NS_CMPRSFLGS) {
693 case 0: /*%< normal case, n == len */
696 case NS_TYPE_ELT: /*%< EDNS0 extended label */
697 if ((l = labellen(cp - 1)) < 0) {
698 errno = EMSGSIZE; /*%< XXX */
703 case NS_CMPRSFLGS: /*%< indirection */
706 default: /*%< illegal type */
720 /* Find the number of octets an nname takes up, including the root label.
721 * (This is basically ns_name_skip() without compression-pointer support.)
722 * ((NOTE: can only return zero if passed-in namesiz argument is zero.))
725 ns_name_length(ns_nname_ct nname, size_t namesiz) {
726 ns_nname_ct orig = nname;
729 while (namesiz-- > 0 && (n = *nname++) != 0) {
730 if ((n & NS_CMPRSFLGS) != 0) {
741 return (nname - orig);
744 /* Compare two nname's for equality. Return -1 on error (setting errno).
747 ns_name_eq(ns_nname_ct a, size_t as, ns_nname_ct b, size_t bs) {
748 ns_nname_ct ae = a + as, be = b + bs;
751 while (ac = *a, bc = *b, ac != 0 && bc != 0) {
752 if ((ac & NS_CMPRSFLGS) != 0 || (bc & NS_CMPRSFLGS) != 0) {
756 if (a + ac >= ae || b + bc >= be) {
760 if (ac != bc || strncasecmp((const char *) ++a,
761 (const char *) ++b, ac) != 0)
765 return (ac == 0 && bc == 0);
768 /* Is domain "A" owned by (at or below) domain "B"?
771 ns_name_owned(ns_namemap_ct a, int an, ns_namemap_ct b, int bn) {
772 /* If A is shorter, it cannot be owned by B. */
776 /* If they are unequal before the length of the shorter, A cannot... */
778 if (a->len != b->len ||
779 strncasecmp((const char *) a->base,
780 (const char *) b->base, a->len) != 0)
786 /* A might be longer or not, but either way, B owns it. */
790 /* Build an array of <base,len> tuples from an nname, top-down order.
791 * Return the number of tuples (labels) thus discovered.
794 ns_name_map(ns_nname_ct nname, size_t namelen, ns_namemap_t map, int mapsize) {
803 /* Extra data follows name? */
811 /* Compression pointer? */
812 if ((n & NS_CMPRSFLGS) != 0) {
817 /* Label too long? */
823 /* Recurse to get rest of name done first. */
824 l = ns_name_map(nname + n, namelen - n, map, mapsize);
828 /* Too many labels? */
830 errno = ENAMETOOLONG;
834 /* We're on our way back up-stack, store current map data. */
840 /* Count the labels in a domain name. Root counts, so COM. has two. This
841 * is to make the result comparable to the result of ns_name_map().
844 ns_name_labels(ns_nname_ct nname, size_t namesiz) {
848 while (namesiz-- > 0 && (n = *nname++) != 0) {
849 if ((n & NS_CMPRSFLGS) != 0) {
867 * Thinking in noninternationalized USASCII (per the DNS spec),
868 * is this characted special ("in need of quoting") ?
876 case 0x22: /*%< '"' */
877 case 0x2E: /*%< '.' */
878 case 0x3B: /*%< ';' */
879 case 0x5C: /*%< '\\' */
880 case 0x28: /*%< '(' */
881 case 0x29: /*%< ')' */
882 /* Special modifiers in zone files. */
883 case 0x40: /*%< '@' */
884 case 0x24: /*%< '$' */
892 * Thinking in noninternationalized USASCII (per the DNS spec),
893 * is this character visible and not a space when printed ?
900 return (ch > 0x20 && ch < 0x7f);
904 * Thinking in noninternationalized USASCII (per the DNS spec),
905 * convert this character to lower case if it's upper case.
909 if (ch >= 0x41 && ch <= 0x5A)
915 * Search for the counted-label name in an array of compressed names.
918 *\li offset from msg if found, or -1.
921 *\li dnptrs is the pointer to the first name on the list,
922 *\li not the pointer to the start of the message.
925 dn_find(const u_char *domain, const u_char *msg,
926 const u_char * const *dnptrs,
927 const u_char * const *lastdnptr)
929 const u_char *dn, *cp, *sp;
930 const u_char * const *cpp;
933 for (cpp = dnptrs; cpp < lastdnptr; cpp++) {
936 * terminate search on:
938 * compression pointer
941 while (*sp != 0 && (*sp & NS_CMPRSFLGS) == 0 &&
942 (sp - msg) < 0x4000) {
945 while ((n = *cp++) != 0) {
947 * check for indirection
949 switch (n & NS_CMPRSFLGS) {
950 case 0: /*%< normal case, n == len */
951 n = labellen(cp - 1); /*%< XXX */
955 for ((void)NULL; n > 0; n--)
956 if (mklower(*dn++) !=
959 /* Is next root for both ? */
960 if (*dn == '\0' && *cp == '\0')
965 case NS_CMPRSFLGS: /*%< indirection */
966 cp = msg + (((n & 0x3f) << 8) | *cp);
969 default: /*%< illegal type */
983 decode_bitstring(const unsigned char **cpp, char *dn, const char *eom)
985 const unsigned char *cp = *cpp;
987 int b, blen, plen, i;
989 if ((blen = (*cp & 0xff)) == 0)
991 plen = (blen + 3) / 4;
992 plen += sizeof("\\[x/]") + (blen > 99 ? 3 : (blen > 9) ? 2 : 1);
993 if (dn + plen >= eom)
997 i = SPRINTF((dn, "\\[x"));
1001 for (b = blen; b > 7; b -= 8, cp++) {
1002 i = SPRINTF((dn, "%02x", *cp & 0xff));
1009 i = SPRINTF((dn, "%02x", tc & (0xff << (8 - b))));
1015 i = SPRINTF((dn, "%1x",
1016 ((tc >> 4) & 0x0f) & (0x0f << (4 - b))));
1021 i = SPRINTF((dn, "/%d]", blen));
1031 encode_bitsring(const char **bp, const char *end, unsigned char **labelp,
1032 unsigned char ** dst, unsigned const char *eom)
1035 const char *cp = *bp;
1038 const char *beg_blen;
1039 char *end_blen = NULL;
1040 int value = 0, count = 0, tbcount = 0, blen = 0;
1042 beg_blen = end_blen = NULL;
1044 /* a bitstring must contain at least 2 characters */
1048 /* XXX: currently, only hex strings are supported */
1051 if (!isxdigit((*cp) & 0xff)) /*%< reject '\[x/BLEN]' */
1054 for (tp = *dst + 1; cp < end && tp < eom; cp++) {
1056 case ']': /*%< end of the bitstring */
1058 if (beg_blen == NULL)
1060 blen = (int)strtol(beg_blen, &end_blen, 10);
1061 if (*end_blen != ']')
1065 *tp++ = ((value << 4) & 0xff);
1066 cp++; /*%< skip ']' */
1073 if (!isdigit(c&0xff))
1075 if (beg_blen == NULL) {
1078 /* blen never begings with 0 */
1084 if (!isxdigit(c&0xff))
1087 value += digitvalue[(int)c];
1101 if (cp >= end || tp >= eom)
1105 * bit length validation:
1106 * If a <length> is present, the number of digits in the <bit-data>
1107 * MUST be just sufficient to contain the number of bits specified
1108 * by the <length>. If there are insignificant bits in a final
1109 * hexadecimal or octal digit, they MUST be zero.
1110 * RFC2673, Section 3.2.
1115 if (((blen + 3) & ~3) != tbcount)
1117 traillen = tbcount - blen; /*%< between 0 and 3 */
1118 if (((value << (8 - traillen)) & 0xff) != 0)
1126 /* encode the type and the significant bit fields */
1127 **labelp = DNS_LABELTYPE_BITSTRING;
1137 labellen(const u_char *lp)
1142 if ((l & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
1143 /* should be avoided by the caller */
1147 if ((l & NS_CMPRSFLGS) == NS_TYPE_ELT) {
1148 if (l == DNS_LABELTYPE_BITSTRING) {
1149 if ((bitlen = *(lp + 1)) == 0)
1151 return ((bitlen + 7 ) / 8 + 1);
1153 return (-1); /*%< unknwon ELT */