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/* Domain name processing functions.
Copyright (C) 1995-2018 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
/*
* Copyright (c) 1985, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*
* Portions Copyright (c) 1993 by Digital Equipment Corporation.
*
* 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, and that
* the name of Digital Equipment Corporation not be used in advertising or
* publicity pertaining to distribution of the document or software without
* specific, written prior permission.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
* WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT
* CORPORATION 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.
*/
/*
* Portions 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 <sys/types.h>
#include <sys/param.h>
#include <netinet/in.h>
#include <arpa/nameser.h>
#include <ctype.h>
#include <resolv.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
/*
* Expand compressed domain name 'comp_dn' to full domain name.
* 'msg' is a pointer to the beginning of the message,
* 'eomorig' points to the first location after the message,
* 'exp_dn' is a pointer to a buffer of size 'length' for the result.
* Return size of compressed name or -1 if there was an error.
*/
int
dn_expand(const u_char *msg, const u_char *eom, const u_char *src,
char *dst, int dstsiz)
{
int n = ns_name_uncompress(msg, eom, src, dst, (size_t)dstsiz);
if (n > 0 && dst[0] == '.')
dst[0] = '\0';
return (n);
}
libresolv_hidden_def (dn_expand)
/*
* Pack domain name 'exp_dn' in presentation form into 'comp_dn'.
* Return the size of the compressed name or -1.
* 'length' is the size of the array pointed to by 'comp_dn'.
*/
int
dn_comp(const char *src, u_char *dst, int dstsiz,
u_char **dnptrs, u_char **lastdnptr)
{
return (ns_name_compress(src, dst, (size_t)dstsiz,
(const u_char **)dnptrs,
(const u_char **)lastdnptr));
}
libresolv_hidden_def (dn_comp)
/*
* Skip over a compressed domain name. Return the size or -1.
*/
int
dn_skipname(const u_char *ptr, const u_char *eom) {
const u_char *saveptr = ptr;
if (ns_name_skip(&ptr, eom) == -1)
return (-1);
return (ptr - saveptr);
}
libresolv_hidden_def (dn_skipname)
/* Return true if the string consists of printable ASCII characters
only. */
static bool
printable_string (const char *dn)
{
while (true)
{
char ch = *dn;
if (ch == '\0')
return true;
if (ch <= ' ' || ch > '~')
return false;
++dn;
}
}
/* Return true if DN points to a name consisting only of [0-9a-zA-Z_-]
characters. DN must be in DNS wire format, without
compression. */
static bool
binary_hnok (const unsigned char *dn)
{
while (true)
{
size_t label_length = *dn;
if (label_length == 0)
break;
++dn;
const unsigned char *label_end = dn + label_length;
do
{
unsigned char ch = *dn;
if (!(('0' <= ch && ch <= '9')
|| ('A' <= ch && ch <= 'Z')
|| ('a' <= ch && ch <= 'z')
|| ch == '-' || ch == '_'))
return false;
++dn;
}
while (dn < label_end);
}
return true;
}
/* Return true if the binary domain name has a first labels which
starts with '-'. */
static inline bool
binary_leading_dash (const unsigned char *dn)
{
return dn[0] > 0 && dn[1] == '-';
}
/* Return 1 if res_hnok is a valid host name. Labels must only
contain [0-9a-zA-Z_-] characters, and the name must not start with
a '-'. The latter is to avoid confusion with program options. */
int
res_hnok (const char *dn)
{
unsigned char buf[NS_MAXCDNAME];
if (!printable_string (dn)
|| ns_name_pton (dn, buf, sizeof (buf)) < 0
|| binary_leading_dash (buf))
return 0;
return binary_hnok (buf);
}
libresolv_hidden_def (res_hnok)
/* Hostname-like (A, MX, WKS) owners can have "*" as their first label
but must otherwise be as a host name. */
int
res_ownok (const char *dn)
{
unsigned char buf[NS_MAXCDNAME];
if (!printable_string (dn)
|| ns_name_pton (dn, buf, sizeof (buf)) < 0
|| binary_leading_dash (buf))
return 0;
if (buf[0] == 1 && buf [1] == '*')
/* Skip over the leading "*." part. */
return binary_hnok (buf + 2);
else
return binary_hnok (buf);
}
/* SOA RNAMEs and RP RNAMEs can have any byte in their first label,
but the rest of the name has to look like a host name. */
int
res_mailok (const char *dn)
{
unsigned char buf[NS_MAXCDNAME];
if (!printable_string (dn)
|| ns_name_pton (dn, buf, sizeof (buf)) < 0)
return 0;
unsigned char label_length = buf[0];
/* "." is a valid missing representation */
if (label_length == 0)
return 1;
/* Skip over the first label. */
unsigned char *tail = buf + 1 + label_length;
if (*tail == 0)
/* More than one label is required (except for "."). */
return 0;
return binary_hnok (tail);
}
/* Return 1 if DN is a syntactically valid domain name. Empty names
are accepted. */
int
res_dnok (const char *dn)
{
unsigned char buf[NS_MAXCDNAME];
return printable_string (dn) && ns_name_pton (dn, buf, sizeof (buf)) >= 0;
}
libresolv_hidden_def (res_dnok)
/*
* This module must export the following externally-visible symbols:
* ___putlong
* ___putshort
* __getlong
* __getshort
* Note that one _ comes from C and the others come from us.
*/
void __putlong(uint32_t src, u_char *dst) { ns_put32(src, dst); }
libresolv_hidden_def (__putlong)
void __putshort(uint16_t src, u_char *dst) { ns_put16(src, dst); }
libresolv_hidden_def (__putshort)
uint32_t _getlong(const u_char *src) { return (ns_get32(src)); }
uint16_t _getshort(const u_char *src) { return (ns_get16(src)); }
#include <shlib-compat.h>
#if SHLIB_COMPAT(libresolv, GLIBC_2_0, GLIBC_2_2)
# undef dn_expand
weak_alias (__dn_expand, dn_expand);
#endif
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