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.
20 #include "port_before.h"
22 #include <sys/types.h>
24 #include <netinet/in.h>
25 #include <arpa/nameser.h>
34 #include "port_after.h"
37 # define SPRINTF(x) strlen(sprintf/**/x)
39 # define SPRINTF(x) ((size_t)sprintf x)
42 #define NS_TYPE_ELT 0x40 /*%< EDNS0 extended label type */
43 #define DNS_LABELTYPE_BITSTRING 0x41
47 static const char digits[] = "0123456789";
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*/
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 *);
85 * Convert an encoded domain name to printable ascii as per RFC1035.
88 *\li Number of bytes written to buffer, or -1 (with errno set)
91 *\li The root is returned as "."
92 *\li All other domains are returned in non absolute form
95 ns_name_ntop(const u_char *src, char *dst, size_t dstsiz)
107 while ((n = *cp++) != 0) {
108 if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
109 /* Some kind of compression pointer. */
120 if ((l = labellen(cp - 1)) < 0) {
121 errno = EMSGSIZE; /*%< XXX */
128 if ((n & NS_CMPRSFLGS) == NS_TYPE_ELT) {
131 if (n != DNS_LABELTYPE_BITSTRING) {
132 /* XXX: labellen should reject this case */
136 if ((m = decode_bitstring(&cp, dn, eom)) < 0)
144 for ((void)NULL; l > 0; l--) {
153 } else if (!printable(c)) {
159 *dn++ = digits[c / 100];
160 *dn++ = digits[(c % 100) / 10];
161 *dn++ = digits[c % 10];
187 * Convert a ascii string into an encoded domain name as per RFC1035.
192 *\li 1 if string was fully qualified
193 *\li 0 is string was not fully qualified
196 *\li Enforces label and domain length limits.
199 ns_name_pton(const char *src, u_char *dst, size_t dstsiz) {
200 return (ns_name_pton2(src, dst, dstsiz, NULL));
204 * ns_name_pton2(src, dst, dstsiz, *dstlen)
205 * Convert a ascii string into an encoded domain name as per RFC1035.
208 * 1 if string was fully qualified
209 * 0 is string was not fully qualified
211 * fills in *dstlen (if non-NULL)
213 * Enforces label and domain length limits.
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;
226 while ((c = *src++) != 0) {
228 if (c == '[') { /*%< start a bit string label */
229 if ((cp = strchr(src, ']')) == NULL) {
230 errno = EINVAL; /*%< ??? */
233 if ((e = encode_bitsring(&src, cp + 2,
241 if ((c = *src++) == 0)
249 else if ((cp = strchr(digits, c)) != NULL) {
250 n = (cp - digits) * 100;
251 if ((c = *src++) == 0 ||
252 (cp = strchr(digits, c)) == NULL) {
256 n += (cp - digits) * 10;
257 if ((c = *src++) == 0 ||
258 (cp = strchr(digits, c)) == NULL) {
270 } else if (c == '\\') {
273 } else if (c == '.') {
274 c = (bp - label - 1);
275 if ((c & NS_CMPRSFLGS) != 0) { /*%< Label too big. */
284 /* Fully qualified ? */
293 if ((bp - dst) > MAXCDNAME) {
298 *dstlen = (bp - dst);
301 if (c == 0 || *src == '.') {
314 c = (bp - label - 1);
315 if ((c & NS_CMPRSFLGS) != 0) { /*%< Label too big. */
332 if ((bp - dst) > MAXCDNAME) { /*%< src too big */
337 *dstlen = (bp - dst);
342 * Convert a network strings labels into all lowercase.
345 *\li Number of bytes written to buffer, or -1 (with errno set)
348 *\li Enforces label and domain length limits.
352 ns_name_ntol(const u_char *src, u_char *dst, size_t dstsiz)
368 while ((n = *cp++) != 0) {
369 if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
370 /* Some kind of compression pointer. */
375 if ((l = labellen(cp - 1)) < 0) {
383 for ((void)NULL; l > 0; l--) {
385 if (isascii(c) && isupper(c))
396 * Unpack a domain name from a message, source may be compressed.
399 *\li -1 if it fails, or consumed octets if it succeeds.
402 ns_name_unpack(const u_char *msg, const u_char *eom, const u_char *src,
403 u_char *dst, size_t dstsiz)
405 return (ns_name_unpack2(msg, eom, src, dst, dstsiz, NULL));
409 * ns_name_unpack2(msg, eom, src, dst, dstsiz, *dstlen)
410 * Unpack a domain name from a message, source may be compressed.
412 * -1 if it fails, or consumed octets if it succeeds.
414 * fills in *dstlen (if non-NULL).
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)
420 const u_char *srcp, *dstlim;
422 int n, len, checked, l;
428 dstlim = dst + dstsiz;
429 if (srcp < msg || srcp >= eom) {
433 /* Fetch next label in domain name. */
434 while ((n = *srcp++) != 0) {
435 /* Check for indirection. */
436 switch (n & NS_CMPRSFLGS) {
440 if ((l = labellen(srcp - 1)) < 0) {
444 if (dstp + l + 1 >= dstlim || srcp + l >= eom) {
450 memcpy(dstp, srcp, l);
461 len = srcp - src + 1;
462 l = ((n & 0x3f) << 8) | (*srcp & 0xff);
463 if (l >= eom - msg) { /*%< Out of range. */
470 * Check for loops in the compressed name;
471 * if we've looked at the whole message,
472 * there must be a loop.
474 if (checked >= eom - msg) {
482 return (-1); /*%< flag error */
487 *dstlen = dstp - dst;
494 * Pack domain name 'domain' into 'comp_dn'.
497 *\li Size of the compressed name, or -1.
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
503 *\li 'lastdnptr' is a pointer to the end of the array pointed to
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
513 ns_name_pack(const u_char *src, u_char *dst, int dstsiz,
514 const u_char **dnptrs, const u_char **lastdnptr)
517 const u_char **cpp, **lpp, *eob, *msg;
525 if (dnptrs != NULL) {
526 if ((msg = *dnptrs++) != NULL) {
527 for (cpp = dnptrs; *cpp != NULL; cpp++)
529 lpp = cpp; /*%< end of list to search */
534 /* make sure the domain we are about to add is legal */
540 if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
544 if ((l0 = labellen(srcp)) < 0) {
556 /* from here on we need to reset compression pointer array on error */
559 /* Look to see if we can use pointers. */
561 if (n != 0 && msg != NULL) {
562 l = dn_find(srcp, msg, (const u_char * const *)dnptrs,
563 (const u_char * const *)lpp);
565 if (dstp + 1 >= eob) {
568 *dstp++ = (l >> 8) | NS_CMPRSFLGS;
572 /* Not found, save it. */
573 if (lastdnptr != NULL && cpp < lastdnptr - 1 &&
574 (dstp - msg) < 0x4000 && first) {
580 /* copy label to buffer */
581 if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
582 /* Should not happen. */
586 if (dstp + 1 + n >= eob) {
589 memcpy(dstp, srcp, n + 1);
605 * Expand compressed domain name to presentation format.
608 *\li Number of bytes read out of `src', or -1 (with errno set).
611 *\li Root domain returns as "." not "".
614 ns_name_uncompress(const u_char *msg, const u_char *eom, const u_char *src,
615 char *dst, size_t dstsiz)
617 u_char tmp[NS_MAXCDNAME];
620 if ((n = ns_name_unpack(msg, eom, src, tmp, sizeof tmp)) == -1)
622 if (ns_name_ntop(tmp, dst, dstsiz) == -1)
628 * Compress a domain name into wire format, using compression pointers.
631 *\li Number of bytes consumed in `dst' or -1 (with errno set).
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.
643 ns_name_compress(const char *src, u_char *dst, size_t dstsiz,
644 const u_char **dnptrs, const u_char **lastdnptr)
646 u_char tmp[NS_MAXCDNAME];
648 if (ns_name_pton(src, tmp, sizeof tmp) == -1)
650 return (ns_name_pack(tmp, dst, dstsiz, dnptrs, lastdnptr));
654 * Reset dnptrs so that there are no active references to pointers at or
658 ns_name_rollback(const u_char *src, const u_char **dnptrs,
659 const u_char **lastdnptr)
661 while (dnptrs < lastdnptr && *dnptrs != NULL) {
662 if (*dnptrs >= src) {
671 * Advance *ptrptr to skip over the compressed name it points at.
674 *\li 0 on success, -1 (with errno set) on failure.
677 ns_name_skip(const u_char **ptrptr, const u_char *eom)
684 while (cp < eom && (n = *cp++) != 0) {
685 /* Check for indirection. */
686 switch (n & NS_CMPRSFLGS) {
687 case 0: /*%< normal case, n == len */
690 case NS_TYPE_ELT: /*%< EDNS0 extended label */
691 if (cp < eom && (l = labellen(cp - 1)) < 0) {
692 errno = EMSGSIZE; /*%< XXX */
697 case NS_CMPRSFLGS: /*%< indirection */
700 default: /*%< illegal type */
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.))
719 ns_name_length(ns_nname_ct nname, size_t namesiz) {
720 ns_nname_ct orig = nname;
723 while (namesiz-- > 0 && (n = *nname++) != 0) {
724 if ((n & NS_CMPRSFLGS) != 0) {
735 return (nname - orig);
738 /* Compare two nname's for equality. Return -1 on error (setting errno).
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;
745 while (ac = *a, bc = *b, ac != 0 && bc != 0) {
746 if ((ac & NS_CMPRSFLGS) != 0 || (bc & NS_CMPRSFLGS) != 0) {
750 if (a + ac >= ae || b + bc >= be) {
754 if (ac != bc || strncasecmp((const char *) ++a,
755 (const char *) ++b, ac) != 0)
759 return (ac == 0 && bc == 0);
762 /* Is domain "A" owned by (at or below) domain "B"?
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. */
770 /* If they are unequal before the length of the shorter, A cannot... */
772 if (a->len != b->len ||
773 strncasecmp((const char *) a->base,
774 (const char *) b->base, a->len) != 0)
780 /* A might be longer or not, but either way, B owns it. */
784 /* Build an array of <base,len> tuples from an nname, top-down order.
785 * Return the number of tuples (labels) thus discovered.
788 ns_name_map(ns_nname_ct nname, size_t namelen, ns_namemap_t map, int mapsize) {
797 /* Extra data follows name? */
805 /* Compression pointer? */
806 if ((n & NS_CMPRSFLGS) != 0) {
811 /* Label too long? */
817 /* Recurse to get rest of name done first. */
818 l = ns_name_map(nname + n, namelen - n, map, mapsize);
822 /* Too many labels? */
824 errno = ENAMETOOLONG;
828 /* We're on our way back up-stack, store current map data. */
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().
838 ns_name_labels(ns_nname_ct nname, size_t namesiz) {
842 while (namesiz-- > 0 && (n = *nname++) != 0) {
843 if ((n & NS_CMPRSFLGS) != 0) {
861 * Thinking in noninternationalized USASCII (per the DNS spec),
862 * is this characted special ("in need of quoting") ?
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: /*%< '$' */
886 * Thinking in noninternationalized USASCII (per the DNS spec),
887 * is this character visible and not a space when printed ?
894 return (ch > 0x20 && ch < 0x7f);
898 * Thinking in noninternationalized USASCII (per the DNS spec),
899 * convert this character to lower case if it's upper case.
903 if (ch >= 0x41 && ch <= 0x5A)
909 * Search for the counted-label name in an array of compressed names.
912 *\li offset from msg if found, or -1.
915 *\li dnptrs is the pointer to the first name on the list,
916 *\li not the pointer to the start of the message.
919 dn_find(const u_char *domain, const u_char *msg,
920 const u_char * const *dnptrs,
921 const u_char * const *lastdnptr)
923 const u_char *dn, *cp, *sp;
924 const u_char * const *cpp;
927 for (cpp = dnptrs; cpp < lastdnptr; cpp++) {
930 * terminate search on:
932 * compression pointer
935 while (*sp != 0 && (*sp & NS_CMPRSFLGS) == 0 &&
936 (sp - msg) < 0x4000) {
939 while ((n = *cp++) != 0) {
941 * check for indirection
943 switch (n & NS_CMPRSFLGS) {
944 case 0: /*%< normal case, n == len */
945 n = labellen(cp - 1); /*%< XXX */
949 for ((void)NULL; n > 0; n--)
950 if (mklower(*dn++) !=
953 /* Is next root for both ? */
954 if (*dn == '\0' && *cp == '\0')
959 case NS_CMPRSFLGS: /*%< indirection */
960 cp = msg + (((n & 0x3f) << 8) | *cp);
963 default: /*%< illegal type */
977 decode_bitstring(const unsigned char **cpp, char *dn, const char *eom)
979 const unsigned char *cp = *cpp;
981 int b, blen, plen, i;
983 if ((blen = (*cp & 0xff)) == 0)
985 plen = (blen + 3) / 4;
986 plen += sizeof("\\[x/]") + (blen > 99 ? 3 : (blen > 9) ? 2 : 1);
987 if (dn + plen >= eom)
991 i = SPRINTF((dn, "\\[x"));
995 for (b = blen; b > 7; b -= 8, cp++) {
996 i = SPRINTF((dn, "%02x", *cp & 0xff));
1003 i = SPRINTF((dn, "%02x", tc & (0xff << (8 - b))));
1009 i = SPRINTF((dn, "%1x",
1010 ((tc >> 4) & 0x0f) & (0x0f << (4 - b))));
1015 i = SPRINTF((dn, "/%d]", blen));
1025 encode_bitsring(const char **bp, const char *end, unsigned char **labelp,
1026 unsigned char ** dst, unsigned const char *eom)
1029 const char *cp = *bp;
1032 const char *beg_blen;
1033 char *end_blen = NULL;
1034 int value = 0, count = 0, tbcount = 0, blen = 0;
1036 beg_blen = end_blen = NULL;
1038 /* a bitstring must contain at least 2 characters */
1042 /* XXX: currently, only hex strings are supported */
1045 if (!isxdigit((*cp) & 0xff)) /*%< reject '\[x/BLEN]' */
1048 for (tp = *dst + 1; cp < end && tp < eom; cp++) {
1050 case ']': /*%< end of the bitstring */
1052 if (beg_blen == NULL)
1054 blen = (int)strtol(beg_blen, &end_blen, 10);
1055 if (*end_blen != ']')
1059 *tp++ = ((value << 4) & 0xff);
1060 cp++; /*%< skip ']' */
1067 if (!isdigit(c&0xff))
1069 if (beg_blen == NULL) {
1072 /* blen never begings with 0 */
1078 if (!isxdigit(c&0xff))
1081 value += digitvalue[(int)c];
1095 if (cp >= end || tp >= eom)
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.
1109 if (((blen + 3) & ~3) != tbcount)
1111 traillen = tbcount - blen; /*%< between 0 and 3 */
1112 if (((value << (8 - traillen)) & 0xff) != 0)
1120 /* encode the type and the significant bit fields */
1121 **labelp = DNS_LABELTYPE_BITSTRING;
1131 labellen(const u_char *lp)
1136 if ((l & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
1137 /* should be avoided by the caller */
1141 if ((l & NS_CMPRSFLGS) == NS_TYPE_ELT) {
1142 if (l == DNS_LABELTYPE_BITSTRING) {
1143 if ((bitlen = *(lp + 1)) == 0)
1145 return ((bitlen + 7 ) / 8 + 1);
1147 return (-1); /*%< unknown ELT */