Sweden-Number/dlls/dnsapi/ns_name.c

448 lines
8.8 KiB
C

/*
* 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.
*/
#include "config.h"
#ifdef HAVE_RESOLV
#include <sys/types.h>
#ifdef HAVE_NETINET_IN_H
# include <netinet/in.h>
#endif
#ifdef HAVE_ARPA_NAMESER_H
# include <arpa/nameser.h>
#endif
#include <ctype.h>
#include <errno.h>
#ifdef HAVE_RESOLV_H
# include <resolv.h>
#endif
#include <string.h>
/* Data. */
static const char digits[] = "0123456789";
/* Forward. */
static int special(int);
static int printable(int);
/* Public. */
/*
* dns_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
dns_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 && n != 0x41) {
/* Some kind of compression pointer. */
return (-1);
}
if (dn != dst) {
if (dn >= eom) {
return (-1);
}
*dn++ = '.';
}
if (n == 0x41) {
n = *cp++ / 8;
if (dn + n * 2 + 4 >= eom) {
return (-1);
}
*dn++ = '\\';
*dn++ = '[';
*dn++ = 'x';
while (n-- > 0) {
unsigned u;
c = *cp++;
u = c >> 4;
*dn++ = u > 9 ? 'a' + u - 10 : '0' + u;
u = c & 0xf;
*dn++ = u > 9 ? 'a' + u - 10 : '0' + u;
}
*dn++ = ']';
continue;
}
if (dn + n >= eom) {
return (-1);
}
while (n-- > 0) {
c = *cp++;
if (special(c)) {
if (dn + 1 >= eom) {
return (-1);
}
*dn++ = '\\';
*dn++ = (char)c;
} else if (!printable(c)) {
if (dn + 3 >= eom) {
return (-1);
}
*dn++ = '\\';
*dn++ = digits[c / 100];
*dn++ = digits[(c % 100) / 10];
*dn++ = digits[c % 10];
} else {
if (dn >= eom) {
return (-1);
}
*dn++ = (char)c;
}
}
}
if (dn == dst) {
if (dn >= eom) {
return (-1);
}
*dn++ = '.';
}
if (dn >= eom) {
return (-1);
}
*dn++ = '\0';
return (dn - dst);
}
/*
* dns_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
dns_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) {
return (-1);
}
n += (cp - digits) * 10;
if ((c = *src++) == 0 ||
(cp = strchr(digits, c)) == NULL) {
return (-1);
}
n += (cp - digits);
if (n > 255) {
return (-1);
}
c = n;
} else if (c == '[' && label == bp - 1 && *src == 'x') {
/* Theoretically we would have to handle \[o
as well but we do not since we do not need
it internally. */
*label = 0x41;
label = bp++;
++src;
while (isxdigit (*src)) {
n = *src > '9' ? *src - 'a' + 10 : *src - '0';
++src;
if (! isxdigit(*src)) {
return (-1);
}
n <<= 4;
n += *src > '9' ? *src - 'a' + 10 : *src - '0';
if (bp + 1 >= eom) {
return (-1);
}
*bp++ = n;
++src;
}
*label = (bp - label - 1) * 8;
if (*src++ != ']' || *src++ != '.') {
return (-1);
}
escaped = 0;
label = bp++;
if (bp >= eom) {
return (-1);
}
continue;
}
escaped = 0;
} else if (c == '\\') {
escaped = 1;
continue;
} else if (c == '.') {
c = (bp - label - 1);
if ((c & NS_CMPRSFLGS) != 0) { /* Label too big. */
return (-1);
}
if (label >= eom) {
return (-1);
}
*label = c;
/* Fully qualified ? */
if (*src == '\0') {
if (c != 0) {
if (bp >= eom) {
return (-1);
}
*bp++ = '\0';
}
if ((bp - dst) > NS_MAXCDNAME) {
return (-1);
}
return (1);
}
if (c == 0 || *src == '.') {
return (-1);
}
label = bp++;
continue;
}
if (bp >= eom) {
return (-1);
}
*bp++ = (u_char)c;
}
c = (bp - label - 1);
if ((c & NS_CMPRSFLGS) != 0) { /* Label too big. */
return (-1);
}
if (label >= eom) {
return (-1);
}
*label = c;
if (c != 0) {
if (bp >= eom) {
return (-1);
}
*bp++ = 0;
}
if ((bp - dst) > NS_MAXCDNAME) { /* src too big */
return (-1);
}
return (0);
}
/*
* dns_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.
*/
static int
dns_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, len, checked;
len = -1;
checked = 0;
dstp = dst;
srcp = src;
dstlim = dst + dstsiz;
if (srcp < msg || srcp >= eom) {
return (-1);
}
/* Fetch next label in domain name. */
while ((n = *srcp++) != 0) {
/* Check for indirection. */
switch (n & NS_CMPRSFLGS) {
case 0x40:
if (n == 0x41) {
if (dstp + 1 >= dstlim) {
return (-1);
}
*dstp++ = 0x41;
n = *srcp++ / 8;
++checked;
} else {
return (-1); /* flag error */
}
/* FALLTHROUGH */
case 0:
/* Limit checks. */
if (dstp + n + 1 >= dstlim || srcp + n >= eom) {
return (-1);
}
checked += n + 1;
dstp = memcpy(dstp, srcp - 1, n + 1);
dstp += n + 1;
srcp += n;
break;
case NS_CMPRSFLGS:
if (srcp >= eom) {
return (-1);
}
if (len < 0)
len = srcp - src + 1;
srcp = msg + (((n & 0x3f) << 8) | (*srcp & 0xff));
if (srcp < msg || srcp >= eom) { /* Out of range. */
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) {
return (-1);
}
break;
default:
return (-1); /* flag error */
}
}
*dstp = '\0';
if (len < 0)
len = srcp - src;
return (len);
}
/*
* dns_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
dns_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 = dns_ns_name_unpack(msg, eom, src, tmp, sizeof tmp)) == -1)
return (-1);
if (dns_ns_name_ntop(tmp, dst, dstsiz) == -1)
return (-1);
return (n);
}
/*
* dns_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
dns_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 */
return (-1);
}
break;
}
if (cp > eom) {
return (-1);
}
*ptrptr = cp;
return (0);
}
/* Private. */
/*
* special(ch)
* Thinking in noninternationalized USASCII (per the DNS spec),
* is this character 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);
}
#endif /* HAVE_RESOLV */