vlmcsd/ns_name.c

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7.4 KiB
C
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2015-11-29 09:30:52 +00:00
/*
* Copyright (c) 1996,1999 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.
*/
/*
* Modified by Hotbird64 for use with vlmcs.
*/
#ifndef CONFIG
#define CONFIG "config.h"
#endif // CONFIG
#include CONFIG
#ifdef DNS_PARSER_INTERNAL
#ifndef NO_DNS
#include <sys/types.h>
#include <errno.h>
#include <string.h>
#include <ctype.h>
#include <stdlib.h>
#include <stdio.h>
#include <limits.h>
#include "types.h"
#include "ns_name.h"
#ifdef SPRINTF_CHAR
# define SPRINTF(x) strlen(sprintf/**/x)
#else
# define SPRINTF(x) ((size_t)sprintf x)
#endif
#define NS_TYPE_ELT 0x40 /* EDNS0 extended label type */
#define DNS_LABELTYPE_BITSTRING 0x41
#define NS_MAXCDNAME 255
#define NS_CMPRSFLGS 0xc0
/* Data. */
static char digits[] = "0123456789";
/* Forward. */
static int special_vlmcsd(int);
static int printable_vlmcsd(int);
static int labellen_vlmcsd(const uint8_t *);
static int decode_bitstring_vlmcsd(const char **, char *, const char *);
/*
* 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
*/
static int
ns_name_ntop_vlmcsd(const uint8_t *src, char *dst, size_t dstsiz)
{
const uint8_t *cp;
char *dn, *eom;
uint8_t c;
uint32_t n;
int l;
cp = src;
dn = dst;
eom = dst + dstsiz;
while ((n = *cp++) != 0) {
if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
/* Some kind of compression pointer. */
errno = EMSGSIZE;
return (-1);
}
if (dn != dst) {
if (dn >= eom) {
errno = EMSGSIZE;
return (-1);
}
*dn++ = '.';
}
if ((l = labellen_vlmcsd(cp - 1)) < 0) {
errno = EMSGSIZE; /* XXX */
return(-1);
}
if (dn + l >= eom) {
errno = EMSGSIZE;
return (-1);
}
if ((n & NS_CMPRSFLGS) == NS_TYPE_ELT) {
int m;
if (n != DNS_LABELTYPE_BITSTRING) {
/* XXX: labellen should reject this case */
errno = EINVAL;
return(-1);
}
if ((m = decode_bitstring_vlmcsd((const char **)&cp, dn, eom)) < 0)
{
errno = EMSGSIZE;
return(-1);
}
dn += m;
continue;
}
for ((void)NULL; l > 0; l--) {
c = *cp++;
if (special_vlmcsd(c)) {
if (dn + 1 >= eom) {
errno = EMSGSIZE;
return (-1);
}
*dn++ = '\\';
*dn++ = (char)c;
} else if (!printable_vlmcsd(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);
}
static int
ns_name_unpack_vlmcsd(const uint8_t *msg, const uint8_t *eom, const uint8_t *src,
uint8_t *dst, size_t dstsiz)
{
const uint8_t *srcp, *dstlim;
uint8_t *dstp;
int n, len, checked, l;
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:
case NS_TYPE_ELT:
/* Limit checks. */
if ((l = labellen_vlmcsd(srcp - 1)) < 0) {
errno = EMSGSIZE;
return(-1);
}
if (dstp + l + 1 >= dstlim || srcp + l >= eom) {
errno = EMSGSIZE;
return (-1);
}
checked += l + 1;
*dstp++ = n;
memcpy(dstp, srcp, l);
dstp += l;
srcp += l;
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_uncompress_vlmcsd(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_vlmcsd(const uint8_t *msg, const uint8_t *eom, const uint8_t *src,
char *dst, size_t dstsiz)
{
uint8_t tmp[NS_MAXCDNAME];
int n;
if ((n = ns_name_unpack_vlmcsd(msg, eom, src, tmp, sizeof tmp)) == -1)
return (-1);
if (ns_name_ntop_vlmcsd(tmp, dst, dstsiz) == -1)
return (-1);
return (n);
}
/*
* special(ch)
* Thinking in noninternationalized USASCII (per the DNS spec),
* is this characted special ("in need of quoting") ?
* return:
* boolean.
*/
static int
special_vlmcsd(int ch) {
switch (ch) {
case 0x22: /* '"' */
case 0x2E: /* '.' */
case 0x3B: /* ';' */
case 0x5C: /* '\\' */
case 0x28: /* '(' */
case 0x29: /* ')' */
/* 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_vlmcsd(int ch) {
return (ch > 0x20 && ch < 0x7f);
}
static int
decode_bitstring_vlmcsd(const char **cpp, char *dn, const char *eom)
{
const char *cp = *cpp;
char *beg = dn, tc;
int b, blen, plen;
if ((blen = (*cp & 0xff)) == 0)
blen = 256;
plen = (blen + 3) / 4;
plen += sizeof("\\[x/]") + (blen > 99 ? 3 : (blen > 9) ? 2 : 1);
if (dn + plen >= eom)
return(-1);
cp++;
dn += SPRINTF((dn, "\\[x"));
for (b = blen; b > 7; b -= 8, cp++)
dn += SPRINTF((dn, "%02x", *cp & 0xff));
if (b > 4) {
tc = *cp++;
dn += SPRINTF((dn, "%02x", tc & (0xff << (8 - b))));
} else if (b > 0) {
tc = *cp++;
dn += SPRINTF((dn, "%1x",
((tc >> 4) & 0x0f) & (0x0f << (4 - b))));
}
dn += SPRINTF((dn, "/%d]", blen));
*cpp = cp;
return(dn - beg);
}
static int
labellen_vlmcsd(const uint8_t *lp)
{
int bitlen;
uint8_t l = *lp;
if ((l & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
/* should be avoided by the caller */
return(-1);
}
if ((l & NS_CMPRSFLGS) == NS_TYPE_ELT) {
if (l == DNS_LABELTYPE_BITSTRING) {
if ((bitlen = *(lp + 1)) == 0)
bitlen = 256;
return((bitlen + 7 ) / 8 + 1);
}
return(-1); /* unknwon ELT */
}
return(l);
}
#endif // !NO_DNS
#endif // DNS_PARSER_INTERNAL