lib/libc/nameser/ns_parse.c

   1 /*
   2  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
   3  * Copyright (c) 1996,1999 by Internet Software Consortium.
   4  *
   5  * Permission to use, copy, modify, and distribute this software for any
   6  * purpose with or without fee is hereby granted, provided that the above
   7  * copyright notice and this permission notice appear in all copies.
   8  *
   9  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
  10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  11  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
  12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
  15  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  16  */
  17
  18 #ifndef lint
  19 static const char rcsid[] = "$Id: ns_parse.c,v 1.9 2007/08/27 03:32:26 marka Exp $";
  20 #endif
  21
  22 /* Import. */
  23
  24 #include "port_before.h"
  25
  26 #include <sys/types.h>
  27
  28 #include <netinet/in.h>
  29 #include <arpa/nameser.h>
  30
  31 #include <errno.h>
  32 #include <resolv.h>
  33 #include <string.h>
  34
  35 #include "port_after.h"
  36
  37 /* Forward. */
  38
  39 static void     setsection(ns_msg *msg, ns_sect sect);
  40
  41 /* Macros. */
  42
  43 #if !defined(SOLARIS2) || defined(__COVERITY__)
  44 #define RETERR(err) do { errno = (err); return (-1); } while (0)
  45 #else
  46 #define RETERR(err) \
  47         do { errno = (err); if (errno == errno) return (-1); } while (0)
  48 #endif
  49
  50 /* Public. */
  51
  52 /* These need to be in the same order as the nres.h:ns_flag enum. */
  53 struct _ns_flagdata _ns_flagdata[16] = {
  54         { 0x8000, 15 },         /*%< qr. */
  55         { 0x7800, 11 },         /*%< opcode. */
  56         { 0x0400, 10 },         /*%< aa. */
  57         { 0x0200, 9 },          /*%< tc. */
  58         { 0x0100, 8 },          /*%< rd. */
  59         { 0x0080, 7 },          /*%< ra. */
  60         { 0x0040, 6 },          /*%< z. */
  61         { 0x0020, 5 },          /*%< ad. */
  62         { 0x0010, 4 },          /*%< cd. */
  63         { 0x000f, 0 },          /*%< rcode. */
  64         { 0x0000, 0 },          /*%< expansion (1/6). */
  65         { 0x0000, 0 },          /*%< expansion (2/6). */
  66         { 0x0000, 0 },          /*%< expansion (3/6). */
  67         { 0x0000, 0 },          /*%< expansion (4/6). */
  68         { 0x0000, 0 },          /*%< expansion (5/6). */
  69         { 0x0000, 0 },          /*%< expansion (6/6). */
  70 };
  71
  72 int ns_msg_getflag(ns_msg handle, int flag) {
  73         return(((handle)._flags & _ns_flagdata[flag].mask) >> _ns_flagdata[flag].shift);
  74 }
  75
  76 int
  77 ns_skiprr(const u_char *ptr, const u_char *eom, ns_sect section, int count) {
  78         const u_char *optr = ptr;
  79
  80         for ((void)NULL; count > 0; count--) {
  81                 int b, rdlength;
  82
  83                 b = dn_skipname(ptr, eom);
  84                 if (b < 0)
  85                         RETERR(EMSGSIZE);
  86                 ptr += b/*Name*/ + NS_INT16SZ/*Type*/ + NS_INT16SZ/*Class*/;
  87                 if (section != ns_s_qd) {
  88                         if (ptr + NS_INT32SZ + NS_INT16SZ > eom)
  89                                 RETERR(EMSGSIZE);
  90                         ptr += NS_INT32SZ/*TTL*/;
  91                         NS_GET16(rdlength, ptr);
  92                         ptr += rdlength/*RData*/;
  93                 }
  94         }
  95         if (ptr > eom)
  96                 RETERR(EMSGSIZE);
  97         return (ptr - optr);
  98 }
  99
 100 int
 101 ns_initparse(const u_char *msg, int msglen, ns_msg *handle) {
 102         const u_char *eom = msg + msglen;
 103         int i;
 104
 105         memset(handle, 0x5e, sizeof *handle);
 106         handle->_msg = msg;
 107         handle->_eom = eom;
 108         if (msg + NS_INT16SZ > eom)
 109                 RETERR(EMSGSIZE);
 110         NS_GET16(handle->_id, msg);
 111         if (msg + NS_INT16SZ > eom)
 112                 RETERR(EMSGSIZE);
 113         NS_GET16(handle->_flags, msg);
 114         for (i = 0; i < ns_s_max; i++) {
 115                 if (msg + NS_INT16SZ > eom)
 116                         RETERR(EMSGSIZE);
 117                 NS_GET16(handle->_counts[i], msg);
 118         }
 119         for (i = 0; i < ns_s_max; i++)
 120                 if (handle->_counts[i] == 0)
 121                         handle->_sections[i] = NULL;
 122                 else {
 123                         int b = ns_skiprr(msg, eom, (ns_sect)i,
 124                                           handle->_counts[i]);
 125
 126                         if (b < 0)
 127                                 return (-1);
 128                         handle->_sections[i] = msg;
 129                         msg += b;
 130                 }
 131         if (msg != eom)
 132                 RETERR(EMSGSIZE);
 133         setsection(handle, ns_s_max);
 134         return (0);
 135 }
 136
 137 int
 138 ns_parserr(ns_msg *handle, ns_sect section, int rrnum, ns_rr *rr) {
 139         int b;
 140         int tmp;
 141
 142         /* Make section right. */
 143         tmp = section;
 144         if (tmp < 0 || section >= ns_s_max)
 145                 RETERR(ENODEV);
 146         if (section != handle->_sect)
 147                 setsection(handle, section);
 148
 149         /* Make rrnum right. */
 150         if (rrnum == -1)
 151                 rrnum = handle->_rrnum;
 152         if (rrnum < 0 || rrnum >= handle->_counts[(int)section])
 153                 RETERR(ENODEV);
 154         if (rrnum < handle->_rrnum)
 155                 setsection(handle, section);
 156         if (rrnum > handle->_rrnum) {
 157                 b = ns_skiprr(handle->_msg_ptr, handle->_eom, section,
 158                               rrnum - handle->_rrnum);
 159
 160                 if (b < 0)
 161                         return (-1);
 162                 handle->_msg_ptr += b;
 163                 handle->_rrnum = rrnum;
 164         }
 165
 166         /* Do the parse. */
 167         b = dn_expand(handle->_msg, handle->_eom,
 168                       handle->_msg_ptr, rr->name, NS_MAXDNAME);
 169         if (b < 0)
 170                 return (-1);
 171         handle->_msg_ptr += b;
 172         if (handle->_msg_ptr + NS_INT16SZ + NS_INT16SZ > handle->_eom)
 173                 RETERR(EMSGSIZE);
 174         NS_GET16(rr->type, handle->_msg_ptr);
 175         NS_GET16(rr->rr_class, handle->_msg_ptr);
 176         if (section == ns_s_qd) {
 177                 rr->ttl = 0;
 178                 rr->rdlength = 0;
 179                 rr->rdata = NULL;
 180         } else {
 181                 if (handle->_msg_ptr + NS_INT32SZ + NS_INT16SZ > handle->_eom)
 182                         RETERR(EMSGSIZE);
 183                 NS_GET32(rr->ttl, handle->_msg_ptr);
 184                 NS_GET16(rr->rdlength, handle->_msg_ptr);
 185                 if (handle->_msg_ptr + rr->rdlength > handle->_eom)
 186                         RETERR(EMSGSIZE);
 187                 rr->rdata = handle->_msg_ptr;
 188                 handle->_msg_ptr += rr->rdlength;
 189         }
 190         if (++handle->_rrnum > handle->_counts[(int)section])
 191                 setsection(handle, (ns_sect)((int)section + 1));
 192
 193         /* All done. */
 194         return (0);
 195 }
 196
 197 /* Private. */
 198
 199 static void
 200 setsection(ns_msg *msg, ns_sect sect) {
 201         msg->_sect = sect;
 202         if (sect == ns_s_max) {
 203                 msg->_rrnum = -1;
 204                 msg->_msg_ptr = NULL;
 205         } else {
 206                 msg->_rrnum = 0;
 207                 msg->_msg_ptr = msg->_sections[(int)sect];
 208         }
 209 }
 210
 211 /*! \file */