594 lines
13 KiB
C
594 lines
13 KiB
C
/*
|
|
* Copyright (c) 1996 by Internet Software Consortium.
|
|
*
|
|
* Permission to use, copy, modify, and distribute this software for any
|
|
* purpose with or without fee is hereby granted, provided that the above
|
|
* copyright notice and this permission notice appear in all copies.
|
|
*
|
|
* THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
|
|
* ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
|
|
* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
|
|
* CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
|
|
* DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
|
|
* PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
|
|
* ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
|
|
* SOFTWARE.
|
|
*/
|
|
|
|
#ifndef lint
|
|
static char rcsid[] = "$FreeBSD$";
|
|
#endif
|
|
|
|
#include <sys/types.h>
|
|
|
|
#include <netinet/in.h>
|
|
#include <arpa/nameser.h>
|
|
|
|
#include <errno.h>
|
|
#include <resolv.h>
|
|
#include <string.h>
|
|
|
|
/* Data. */
|
|
|
|
static char digits[] = "0123456789";
|
|
|
|
/* Forward. */
|
|
|
|
static int special(int);
|
|
static int printable(int);
|
|
static int dn_find(const u_char *, const u_char *,
|
|
const u_char * const *,
|
|
const u_char * const *);
|
|
|
|
/* Public. */
|
|
|
|
/*
|
|
* ns_name_ntop(src, dst, dstsiz)
|
|
* Convert an encoded domain name to printable ascii as per RFC1035.
|
|
* return:
|
|
* Number of bytes written to buffer, or -1 (with errno set)
|
|
* notes:
|
|
* The root is returned as "."
|
|
* All other domains are returned in non absolute form
|
|
*/
|
|
int
|
|
ns_name_ntop(const u_char *src, char *dst, size_t dstsiz) {
|
|
const u_char *cp;
|
|
char *dn, *eom;
|
|
u_char c;
|
|
u_int n;
|
|
|
|
cp = src;
|
|
dn = dst;
|
|
eom = dst + dstsiz;
|
|
|
|
while ((n = *cp++) != 0) {
|
|
if ((n & NS_CMPRSFLGS) != 0) {
|
|
/* Some kind of compression pointer. */
|
|
errno = EMSGSIZE;
|
|
return (-1);
|
|
}
|
|
if (dn != dst) {
|
|
if (dn >= eom) {
|
|
errno = EMSGSIZE;
|
|
return (-1);
|
|
}
|
|
*dn++ = '.';
|
|
}
|
|
if (dn + n >= eom) {
|
|
errno = EMSGSIZE;
|
|
return (-1);
|
|
}
|
|
for ((void)NULL; n > 0; n--) {
|
|
c = *cp++;
|
|
if (special(c)) {
|
|
if (dn + 1 >= eom) {
|
|
errno = EMSGSIZE;
|
|
return (-1);
|
|
}
|
|
*dn++ = '\\';
|
|
*dn++ = (char)c;
|
|
} else if (!printable(c)) {
|
|
if (dn + 3 >= eom) {
|
|
errno = EMSGSIZE;
|
|
return (-1);
|
|
}
|
|
*dn++ = '\\';
|
|
*dn++ = digits[c / 100];
|
|
*dn++ = digits[(c % 100) / 10];
|
|
*dn++ = digits[c % 10];
|
|
} else {
|
|
if (dn >= eom) {
|
|
errno = EMSGSIZE;
|
|
return (-1);
|
|
}
|
|
*dn++ = (char)c;
|
|
}
|
|
}
|
|
}
|
|
if (dn == dst) {
|
|
if (dn >= eom) {
|
|
errno = EMSGSIZE;
|
|
return (-1);
|
|
}
|
|
*dn++ = '.';
|
|
}
|
|
if (dn >= eom) {
|
|
errno = EMSGSIZE;
|
|
return (-1);
|
|
}
|
|
*dn++ = '\0';
|
|
return (dn - dst);
|
|
}
|
|
|
|
/*
|
|
* ns_name_pton(src, dst, dstsiz)
|
|
* Convert a ascii string into an encoded domain name as per RFC1035.
|
|
* return:
|
|
* -1 if it fails
|
|
* 1 if string was fully qualified
|
|
* 0 is string was not fully qualified
|
|
* notes:
|
|
* Enforces label and domain length limits.
|
|
*/
|
|
|
|
int
|
|
ns_name_pton(const char *src, u_char *dst, size_t dstsiz) {
|
|
u_char *label, *bp, *eom;
|
|
int c, n, escaped;
|
|
char *cp;
|
|
|
|
escaped = 0;
|
|
bp = dst;
|
|
eom = dst + dstsiz;
|
|
label = bp++;
|
|
|
|
while ((c = *src++) != 0) {
|
|
if (escaped) {
|
|
if ((cp = strchr(digits, c)) != NULL) {
|
|
n = (cp - digits) * 100;
|
|
if ((c = *src++) == 0 ||
|
|
(cp = strchr(digits, c)) == NULL) {
|
|
errno = EMSGSIZE;
|
|
return (-1);
|
|
}
|
|
n += (cp - digits) * 10;
|
|
if ((c = *src++) == 0 ||
|
|
(cp = strchr(digits, c)) == NULL) {
|
|
errno = EMSGSIZE;
|
|
return (-1);
|
|
}
|
|
n += (cp - digits);
|
|
if (n > 255) {
|
|
errno = EMSGSIZE;
|
|
return (-1);
|
|
}
|
|
c = n;
|
|
}
|
|
escaped = 0;
|
|
} else if (c == '\\') {
|
|
escaped = 1;
|
|
continue;
|
|
} else if (c == '.') {
|
|
c = (bp - label - 1);
|
|
if ((c & NS_CMPRSFLGS) != 0) { /* Label too big. */
|
|
errno = EMSGSIZE;
|
|
return (-1);
|
|
}
|
|
if (label >= eom) {
|
|
errno = EMSGSIZE;
|
|
return (-1);
|
|
}
|
|
*label = c;
|
|
/* Fully qualified ? */
|
|
if (*src == '\0') {
|
|
if (c != 0) {
|
|
if (bp >= eom) {
|
|
errno = EMSGSIZE;
|
|
return (-1);
|
|
}
|
|
*bp++ = '\0';
|
|
}
|
|
if ((bp - dst) > MAXCDNAME) {
|
|
errno = EMSGSIZE;
|
|
return (-1);
|
|
}
|
|
return (1);
|
|
}
|
|
if (c == 0) {
|
|
errno = EMSGSIZE;
|
|
return (-1);
|
|
}
|
|
label = bp++;
|
|
continue;
|
|
}
|
|
if (bp >= eom) {
|
|
errno = EMSGSIZE;
|
|
return (-1);
|
|
}
|
|
*bp++ = (u_char)c;
|
|
}
|
|
c = (bp - label - 1);
|
|
if ((c & NS_CMPRSFLGS) != 0) { /* Label too big. */
|
|
errno = EMSGSIZE;
|
|
return (-1);
|
|
}
|
|
if (label >= eom) {
|
|
errno = EMSGSIZE;
|
|
return (-1);
|
|
}
|
|
*label = c;
|
|
if (c != 0) {
|
|
if (bp >= eom) {
|
|
errno = EMSGSIZE;
|
|
return (-1);
|
|
}
|
|
*bp++ = 0;
|
|
}
|
|
if ((bp - dst) > MAXCDNAME) { /* src too big */
|
|
errno = EMSGSIZE;
|
|
return (-1);
|
|
}
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* ns_name_unpack(msg, eom, src, dst, dstsiz)
|
|
* Unpack a domain name from a message, source may be compressed.
|
|
* return:
|
|
* -1 if it fails, or consumed octets if it succeeds.
|
|
*/
|
|
int
|
|
ns_name_unpack(const u_char *msg, const u_char *eom, const u_char *src,
|
|
u_char *dst, size_t dstsiz)
|
|
{
|
|
const u_char *srcp, *dstlim;
|
|
u_char *dstp;
|
|
int n, c, len, checked;
|
|
|
|
len = -1;
|
|
checked = 0;
|
|
dstp = dst;
|
|
srcp = src;
|
|
dstlim = dst + dstsiz;
|
|
if (srcp < msg || srcp >= eom) {
|
|
errno = EMSGSIZE;
|
|
return (-1);
|
|
}
|
|
/* Fetch next label in domain name. */
|
|
while ((n = *srcp++) != 0) {
|
|
/* Check for indirection. */
|
|
switch (n & NS_CMPRSFLGS) {
|
|
case 0:
|
|
/* Limit checks. */
|
|
if (dstp + n + 1 >= dstlim || srcp + n >= eom) {
|
|
errno = EMSGSIZE;
|
|
return (-1);
|
|
}
|
|
checked += n + 1;
|
|
*dstp++ = n;
|
|
memcpy(dstp, srcp, n);
|
|
dstp += n;
|
|
srcp += n;
|
|
break;
|
|
|
|
case NS_CMPRSFLGS:
|
|
if (srcp >= eom) {
|
|
errno = EMSGSIZE;
|
|
return (-1);
|
|
}
|
|
if (len < 0)
|
|
len = srcp - src + 1;
|
|
srcp = msg + (((n & 0x3f) << 8) | (*srcp & 0xff));
|
|
if (srcp < msg || srcp >= eom) { /* Out of range. */
|
|
errno = EMSGSIZE;
|
|
return (-1);
|
|
}
|
|
checked += 2;
|
|
/*
|
|
* Check for loops in the compressed name;
|
|
* if we've looked at the whole message,
|
|
* there must be a loop.
|
|
*/
|
|
if (checked >= eom - msg) {
|
|
errno = EMSGSIZE;
|
|
return (-1);
|
|
}
|
|
break;
|
|
|
|
default:
|
|
errno = EMSGSIZE;
|
|
return (-1); /* flag error */
|
|
}
|
|
}
|
|
*dstp = '\0';
|
|
if (len < 0)
|
|
len = srcp - src;
|
|
return (len);
|
|
}
|
|
|
|
/*
|
|
* ns_name_pack(src, dst, dstsiz, dnptrs, lastdnptr)
|
|
* Pack domain name 'domain' into 'comp_dn'.
|
|
* return:
|
|
* Size of the compressed name, or -1.
|
|
* notes:
|
|
* 'dnptrs' is an array of pointers to previous compressed names.
|
|
* dnptrs[0] is a pointer to the beginning of the message. The array
|
|
* ends with NULL.
|
|
* 'lastdnptr' is a pointer to the end of the array pointed to
|
|
* by 'dnptrs'.
|
|
* Side effects:
|
|
* The list of pointers in dnptrs is updated for labels inserted into
|
|
* the message as we compress the name. If 'dnptr' is NULL, we don't
|
|
* try to compress names. If 'lastdnptr' is NULL, we don't update the
|
|
* list.
|
|
*/
|
|
int
|
|
ns_name_pack(const u_char *src, u_char *dst, int dstsiz,
|
|
const u_char **dnptrs, const u_char **lastdnptr)
|
|
{
|
|
u_char *dstp;
|
|
const u_char **cpp, **lpp, *eob, *msg;
|
|
const u_char *srcp;
|
|
int n, l;
|
|
|
|
srcp = src;
|
|
dstp = dst;
|
|
eob = dstp + dstsiz;
|
|
lpp = cpp = NULL;
|
|
if (dnptrs != NULL) {
|
|
if ((msg = *dnptrs++) != NULL) {
|
|
for (cpp = dnptrs; *cpp != NULL; cpp++)
|
|
(void)NULL;
|
|
lpp = cpp; /* end of list to search */
|
|
}
|
|
} else
|
|
msg = NULL;
|
|
|
|
/* make sure the domain we are about to add is legal */
|
|
l = 0;
|
|
do {
|
|
n = *srcp;
|
|
if ((n & NS_CMPRSFLGS) != 0) {
|
|
errno = EMSGSIZE;
|
|
return (-1);
|
|
}
|
|
l += n + 1;
|
|
if (l > MAXCDNAME) {
|
|
errno = EMSGSIZE;
|
|
return (-1);
|
|
}
|
|
srcp += n + 1;
|
|
} while (n != 0);
|
|
|
|
srcp = src;
|
|
do {
|
|
/* Look to see if we can use pointers. */
|
|
n = *srcp;
|
|
if (n != 0 && msg != NULL) {
|
|
l = dn_find(srcp, msg, (const u_char * const *)dnptrs,
|
|
(const u_char * const *)lpp);
|
|
if (l >= 0) {
|
|
if (dstp + 1 >= eob) {
|
|
errno = EMSGSIZE;
|
|
return (-1);
|
|
}
|
|
*dstp++ = (l >> 8) | NS_CMPRSFLGS;
|
|
*dstp++ = l % 256;
|
|
return (dstp - dst);
|
|
}
|
|
/* Not found, save it. */
|
|
if (lastdnptr != NULL && cpp < lastdnptr - 1 &&
|
|
(dstp - msg) < 0x4000) {
|
|
*cpp++ = dstp;
|
|
*cpp = NULL;
|
|
}
|
|
}
|
|
/* copy label to buffer */
|
|
if (n & NS_CMPRSFLGS) { /* Should not happen. */
|
|
errno = EMSGSIZE;
|
|
return (-1);
|
|
}
|
|
if (dstp + 1 + n >= eob) {
|
|
errno = EMSGSIZE;
|
|
return (-1);
|
|
}
|
|
memcpy(dstp, srcp, n + 1);
|
|
srcp += n + 1;
|
|
dstp += n + 1;
|
|
} while (n != 0);
|
|
|
|
if (dstp > eob) {
|
|
if (msg != NULL)
|
|
*lpp = NULL;
|
|
errno = EMSGSIZE;
|
|
return (-1);
|
|
}
|
|
return (dstp - dst);
|
|
}
|
|
|
|
/*
|
|
* ns_name_uncompress(msg, eom, src, dst, dstsiz)
|
|
* Expand compressed domain name to presentation format.
|
|
* return:
|
|
* Number of bytes read out of `src', or -1 (with errno set).
|
|
* note:
|
|
* Root domain returns as "." not "".
|
|
*/
|
|
int
|
|
ns_name_uncompress(const u_char *msg, const u_char *eom, const u_char *src,
|
|
char *dst, size_t dstsiz)
|
|
{
|
|
u_char tmp[NS_MAXCDNAME];
|
|
int n;
|
|
|
|
if ((n = ns_name_unpack(msg, eom, src, tmp, sizeof tmp)) == -1)
|
|
return (-1);
|
|
if (ns_name_ntop(tmp, dst, dstsiz) == -1)
|
|
return (-1);
|
|
return (n);
|
|
}
|
|
|
|
/*
|
|
* ns_name_compress(src, dst, dstsiz, dnptrs, lastdnptr)
|
|
* Compress a domain name into wire format, using compression pointers.
|
|
* return:
|
|
* Number of bytes consumed in `dst' or -1 (with errno set).
|
|
* notes:
|
|
* 'dnptrs' is an array of pointers to previous compressed names.
|
|
* dnptrs[0] is a pointer to the beginning of the message.
|
|
* The list ends with NULL. 'lastdnptr' is a pointer to the end of the
|
|
* array pointed to by 'dnptrs'. Side effect is to update the list of
|
|
* pointers for labels inserted into the message as we compress the name.
|
|
* If 'dnptr' is NULL, we don't try to compress names. If 'lastdnptr'
|
|
* is NULL, we don't update the list.
|
|
*/
|
|
int
|
|
ns_name_compress(const char *src, u_char *dst, size_t dstsiz,
|
|
const u_char **dnptrs, const u_char **lastdnptr)
|
|
{
|
|
u_char tmp[NS_MAXCDNAME];
|
|
|
|
if (ns_name_pton(src, tmp, sizeof tmp) == -1)
|
|
return (-1);
|
|
return (ns_name_pack(tmp, dst, dstsiz, dnptrs, lastdnptr));
|
|
}
|
|
|
|
/*
|
|
* ns_name_skip(ptrptr, eom)
|
|
* Advance *ptrptr to skip over the compressed name it points at.
|
|
* return:
|
|
* 0 on success, -1 (with errno set) on failure.
|
|
*/
|
|
int
|
|
ns_name_skip(const u_char **ptrptr, const u_char *eom) {
|
|
const u_char *cp;
|
|
u_int n;
|
|
|
|
cp = *ptrptr;
|
|
while (cp < eom && (n = *cp++) != 0) {
|
|
/* Check for indirection. */
|
|
switch (n & NS_CMPRSFLGS) {
|
|
case 0: /* normal case, n == len */
|
|
cp += n;
|
|
continue;
|
|
case NS_CMPRSFLGS: /* indirection */
|
|
cp++;
|
|
break;
|
|
default: /* illegal type */
|
|
errno = EMSGSIZE;
|
|
return (-1);
|
|
}
|
|
break;
|
|
}
|
|
if (cp > eom) {
|
|
errno = EMSGSIZE;
|
|
return (-1);
|
|
}
|
|
*ptrptr = cp;
|
|
return (0);
|
|
}
|
|
|
|
/* Private. */
|
|
|
|
/*
|
|
* special(ch)
|
|
* Thinking in noninternationalized USASCII (per the DNS spec),
|
|
* is this characted special ("in need of quoting") ?
|
|
* return:
|
|
* boolean.
|
|
*/
|
|
static int
|
|
special(int ch) {
|
|
switch (ch) {
|
|
case 0x22: /* '"' */
|
|
case 0x2E: /* '.' */
|
|
case 0x3B: /* ';' */
|
|
case 0x5C: /* '\\' */
|
|
/* Special modifiers in zone files. */
|
|
case 0x40: /* '@' */
|
|
case 0x24: /* '$' */
|
|
return (1);
|
|
default:
|
|
return (0);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* printable(ch)
|
|
* Thinking in noninternationalized USASCII (per the DNS spec),
|
|
* is this character visible and not a space when printed ?
|
|
* return:
|
|
* boolean.
|
|
*/
|
|
static int
|
|
printable(int ch) {
|
|
return (ch > 0x20 && ch < 0x7f);
|
|
}
|
|
|
|
/*
|
|
* Thinking in noninternationalized USASCII (per the DNS spec),
|
|
* convert this character to lower case if it's upper case.
|
|
*/
|
|
static int
|
|
mklower(int ch) {
|
|
if (ch >= 0x41 && ch <= 0x5A)
|
|
return (ch + 0x20);
|
|
return (ch);
|
|
}
|
|
|
|
/*
|
|
* dn_find(domain, msg, dnptrs, lastdnptr)
|
|
* Search for the counted-label name in an array of compressed names.
|
|
* return:
|
|
* offset from msg if found, or -1.
|
|
* notes:
|
|
* dnptrs is the pointer to the first name on the list,
|
|
* not the pointer to the start of the message.
|
|
*/
|
|
static int
|
|
dn_find(const u_char *domain, const u_char *msg,
|
|
const u_char * const *dnptrs,
|
|
const u_char * const *lastdnptr)
|
|
{
|
|
const u_char *dn, *cp, *sp;
|
|
const u_char * const *cpp;
|
|
u_int n;
|
|
|
|
for (cpp = dnptrs; cpp < lastdnptr; cpp++) {
|
|
dn = domain;
|
|
sp = cp = *cpp;
|
|
while ((n = *cp++) != 0) {
|
|
/*
|
|
* check for indirection
|
|
*/
|
|
switch (n & NS_CMPRSFLGS) {
|
|
case 0: /* normal case, n == len */
|
|
if (n != *dn++)
|
|
goto next;
|
|
for ((void)NULL; n > 0; n--)
|
|
if (mklower(*dn++) != mklower(*cp++))
|
|
goto next;
|
|
/* Is next root for both ? */
|
|
if (*dn == '\0' && *cp == '\0')
|
|
return (sp - msg);
|
|
if (*dn)
|
|
continue;
|
|
goto next;
|
|
|
|
case NS_CMPRSFLGS: /* indirection */
|
|
cp = msg + (((n & 0x3f) << 8) | *cp);
|
|
break;
|
|
|
|
default: /* illegal type */
|
|
errno = EMSGSIZE;
|
|
return (-1);
|
|
}
|
|
}
|
|
next: ;
|
|
}
|
|
errno = ENOENT;
|
|
return (-1);
|
|
}
|