dns.subproj/res_comp.c

   1 /*
   2  * Copyright (c) 2018 Apple Inc. All rights reserved.
   3  */
   4 /*
   5  * ++Copyright++ 1985, 1993
   6  * -
   7  * Copyright (c) 1985, 1993
   8  *    The Regents of the University of California.  All rights reserved.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. All advertising materials mentioning features or use of this software
  19  *    must display the following acknowledgement:
  20  *      This product includes software developed by the University of
  21  *      California, Berkeley and its contributors.
  22  * 4. Neither the name of the University nor the names of its contributors
  23  *    may be used to endorse or promote products derived from this software
  24  *    without specific prior written permission.
  25  *
  26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  36  * SUCH DAMAGE.
  37  * -
  38  * Portions Copyright (c) 1993 by Digital Equipment Corporation.
  39  *
  40  * Permission to use, copy, modify, and distribute this software for any
  41  * purpose with or without fee is hereby granted, provided that the above
  42  * copyright notice and this permission notice appear in all copies, and that
  43  * the name of Digital Equipment Corporation not be used in advertising or
  44  * publicity pertaining to distribution of the document or software without
  45  * specific, written prior permission.
  46  *
  47  * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
  48  * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
  49  * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
  50  * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  51  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  52  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  53  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  54  * SOFTWARE.
  55  * -
  56  * --Copyright--
  57  */
  58
  59 #if defined(LIBC_SCCS) && !defined(lint)
  60 static char sccsid[] = "@(#)res_comp.c  8.1 (Berkeley) 6/4/93";
  61 static char rcsid[] = "$Id: res_comp.c,v 1.4 2003/02/18 17:29:24 majka Exp $";
  62 #endif /* LIBC_SCCS and not lint */
  63
  64 #include "libinfo_common.h"
  65
  66 #include <sys/param.h>
  67 #include <netinet/in.h>
  68
  69 #include <stdio.h>
  70 #include <ctype.h>
  71
  72 #include <arpa/nameser_compat.h>
  73 #include <nameser.h>
  74
  75 /*
  76  * Expand compressed domain name 'comp_dn' to full domain name.
  77  * 'msg' is a pointer to the begining of the message,
  78  * 'eomorig' points to the first location after the message,
  79  * 'exp_dn' is a pointer to a buffer of size 'length' for the result.
  80  * Return size of compressed name or -1 if there was an error.
  81  */
  82 LIBINFO_EXPORT
  83 int
  84 dn_expand(const u_char *msg, const u_char *eomorig, const u_char *comp_dn, char *exp_dn, int length)
  85 {
  86         register const u_char *cp;
  87         register char *dn;
  88         register int n, c;
  89         char *eom;
  90         int len = -1, checked = 0;
  91
  92         dn = exp_dn;
  93         cp = comp_dn;
  94         eom = exp_dn + length;
  95         /*
  96          * fetch next label in domain name
  97          */
  98         while ((n = *cp++)) {
  99                 /*
 100                  * Check for indirection
 101                  */
 102                 switch (n & INDIR_MASK) {
 103                 case 0:
 104                         if (dn != exp_dn) {
 105                                 if (dn >= eom)
 106                                         return (-1);
 107                                 *dn++ = '.';
 108                         }
 109                         if (dn+n >= eom)
 110                                 return (-1);
 111                         checked += n + 1;
 112                         while (--n >= 0) {
 113                                 if ((c = *cp++) == '.') {
 114                                         if (dn + n + 2 >= eom)
 115                                                 return (-1);
 116                                         *dn++ = '\\';
 117                                 }
 118                                 *dn++ = c;
 119                                 if (cp >= eomorig)      /* out of range */
 120                                         return (-1);
 121                         }
 122                         break;
 123
 124                 case INDIR_MASK:
 125                         if (len < 0)
 126                                 len = cp - comp_dn + 1;
 127                         cp = msg + (((n & 0x3f) << 8) | (*cp & 0xff));
 128                         if (cp < msg || cp >= eomorig)  /* out of range */
 129                                 return (-1);
 130                         checked += 2;
 131                         /*
 132                          * Check for loops in the compressed name;
 133                          * if we've looked at the whole message,
 134                          * there must be a loop.
 135                          */
 136                         if (checked >= eomorig - msg)
 137                                 return (-1);
 138                         break;
 139
 140                 default:
 141                         return (-1);                    /* flag error */
 142                 }
 143         }
 144         *dn = '\0';
 145         for (dn = exp_dn; (c = *dn) != '\0'; dn++)
 146                 if (isascii(c) && isspace(c))
 147                         return (-1);
 148         if (len < 0)
 149                 len = cp - comp_dn;
 150         return (len);
 151 }
 152
 153 /*
 154  * Skip over a compressed domain name. Return the size or -1.
 155  */
 156 LIBINFO_EXPORT
 157 int
 158 __dn_skipname(const u_char *comp_dn, const u_char *eom)
 159 {
 160         register const u_char *cp;
 161         register int n;
 162
 163         cp = comp_dn;
 164         while (cp < eom && (n = *cp++)) {
 165                 /*
 166                  * check for indirection
 167                  */
 168                 switch (n & INDIR_MASK) {
 169                 case 0:                 /* normal case, n == len */
 170                         cp += n;
 171                         continue;
 172                 case INDIR_MASK:        /* indirection */
 173                         cp++;
 174                         break;
 175                 default:                /* illegal type */
 176                         return (-1);
 177                 }
 178                 break;
 179         }
 180         if (cp > eom)
 181                 return (-1);
 182         return (cp - comp_dn);
 183 }
 184
 185 /*
 186  * Routines to insert/extract short/long's.
 187  */
 188
 189 LIBINFO_EXPORT
 190 u_int16_t
 191 _getshort(const u_char *msgp)
 192 {
 193         u_int16_t u;
 194         GETSHORT(u, msgp);
 195         return u;
 196 }
 197
 198 LIBINFO_EXPORT
 199 u_int32_t
 200 _getlong(const u_char *msgp)
 201 {
 202         u_int32_t u;
 203         GETLONG(u, msgp);
 204         return u;
 205 }