lib/libc/nameser/ns_parse.c

   1 /*      $NetBSD: ns_parse.c,v 1.7 2009/04/12 17:07:17 christos Exp $    */
   2
   3 /*
   4  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
   5  * Copyright (c) 1996,1999 by Internet Software Consortium.
   6  *
   7  * Permission to use, copy, modify, and distribute this software for any
   8  * purpose with or without fee is hereby granted, provided that the above
   9  * copyright notice and this permission notice appear in all copies.
  10  *
  11  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
  12  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  13  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
  14  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  15  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  16  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
  17  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  18  */
  19
  20 #include <sys/cdefs.h>
  21 #ifndef lint
  22 #ifdef notdef
  23 static const char rcsid[] = "Id: ns_parse.c,v 1.10 2009/01/23 19:59:16 each Exp";
  24 #else
  25 __RCSID("$NetBSD: ns_parse.c,v 1.7 2009/04/12 17:07:17 christos Exp $");
  26 #endif
  27 #endif
  28
  29 /* Import. */
  30
  31 #include "port_before.h"
  32
  33 #include <sys/types.h>
  34
  35 #include <netinet/in.h>
  36 #include <arpa/nameser.h>
  37
  38 #include <errno.h>
  39 #include <resolv.h>
  40 #include <string.h>
  41
  42 #include "port_after.h"
  43
  44 /* Forward. */
  45
  46 static void     setsection(ns_msg *msg, ns_sect sect);
  47
  48 /* Macros. */
  49
  50 #if !defined(SOLARIS2) || defined(__COVERITY__)
  51 #define RETERR(err) do { errno = (err); return (-1); } while (/*NOTREACHED*//*CONSTCOND*/0)
  52 #else
  53 #define RETERR(err) \
  54         do { errno = (err); if (errno == errno) return (-1); } while (0)
  55 #endif
  56
  57 #define PARSE_FMT_PRESO 0       /* Parse using presentation-format names */
  58 #define PARSE_FMT_WIRE 1        /* Parse using network-format names */
  59
  60 /* Public. */
  61
  62 /* These need to be in the same order as the nres.h:ns_flag enum. */
  63 struct _ns_flagdata _ns_flagdata[16] = {
  64         { 0x8000, 15 },         /*%< qr. */
  65         { 0x7800, 11 },         /*%< opcode. */
  66         { 0x0400, 10 },         /*%< aa. */
  67         { 0x0200, 9 },          /*%< tc. */
  68         { 0x0100, 8 },          /*%< rd. */
  69         { 0x0080, 7 },          /*%< ra. */
  70         { 0x0040, 6 },          /*%< z. */
  71         { 0x0020, 5 },          /*%< ad. */
  72         { 0x0010, 4 },          /*%< cd. */
  73         { 0x000f, 0 },          /*%< rcode. */
  74         { 0x0000, 0 },          /*%< expansion (1/6). */
  75         { 0x0000, 0 },          /*%< expansion (2/6). */
  76         { 0x0000, 0 },          /*%< expansion (3/6). */
  77         { 0x0000, 0 },          /*%< expansion (4/6). */
  78         { 0x0000, 0 },          /*%< expansion (5/6). */
  79         { 0x0000, 0 },          /*%< expansion (6/6). */
  80 };
  81
  82 int ns_msg_getflag(ns_msg handle, int flag) {
  83         return((u_int32_t)((handle)._flags & _ns_flagdata[flag].mask) >> _ns_flagdata[flag].shift);
  84 }
  85
  86 int
  87 ns_skiprr(const u_char *ptr, const u_char *eom, ns_sect section, int count) {
  88         const u_char *optr = ptr;
  89
  90         for (; count > 0; count--) {
  91                 int b, rdlength;
  92
  93                 b = dn_skipname(ptr, eom);
  94                 if (b < 0)
  95                         RETERR(EMSGSIZE);
  96                 ptr += b/*Name*/ + NS_INT16SZ/*Type*/ + NS_INT16SZ/*Class*/;
  97                 if (section != ns_s_qd) {
  98                         if (ptr + NS_INT32SZ + NS_INT16SZ > eom)
  99                                 RETERR(EMSGSIZE);
 100                         ptr += NS_INT32SZ/*TTL*/;
 101                         NS_GET16(rdlength, ptr);
 102                         ptr += rdlength/*RData*/;
 103                 }
 104         }
 105         if (ptr > eom)
 106                 RETERR(EMSGSIZE);
 107         return (ptr - optr);
 108 }
 109
 110 int
 111 ns_initparse(const u_char *msg, int msglen, ns_msg *handle) {
 112         const u_char *eom = msg + msglen;
 113         int i;
 114
 115         handle->_msg = msg;
 116         handle->_eom = eom;
 117         if (msg + NS_INT16SZ > eom)
 118                 RETERR(EMSGSIZE);
 119         NS_GET16(handle->_id, msg);
 120         if (msg + NS_INT16SZ > eom)
 121                 RETERR(EMSGSIZE);
 122         NS_GET16(handle->_flags, msg);
 123         for (i = 0; i < ns_s_max; i++) {
 124                 if (msg + NS_INT16SZ > eom)
 125                         RETERR(EMSGSIZE);
 126                 NS_GET16(handle->_counts[i], msg);
 127         }
 128         for (i = 0; i < ns_s_max; i++)
 129                 if (handle->_counts[i] == 0)
 130                         handle->_sections[i] = NULL;
 131                 else {
 132                         int b = ns_skiprr(msg, eom, (ns_sect)i,
 133                                           handle->_counts[i]);
 134
 135                         if (b < 0)
 136                                 return (-1);
 137                         handle->_sections[i] = msg;
 138                         msg += b;
 139                 }
 140         if (msg != eom)
 141                 RETERR(EMSGSIZE);
 142         setsection(handle, ns_s_max);
 143         return (0);
 144 }
 145
 146 int
 147 ns_parserr(ns_msg *handle, ns_sect section, int rrnum, ns_rr *rr) {
 148         int b;
 149         int tmp;
 150
 151         /* Make section right. */
 152         tmp = section;
 153         if (tmp < 0 || section >= ns_s_max)
 154                 RETERR(ENODEV);
 155         if (section != handle->_sect)
 156                 setsection(handle, section);
 157
 158         /* Make rrnum right. */
 159         if (rrnum == -1)
 160                 rrnum = handle->_rrnum;
 161         if (rrnum < 0 || rrnum >= handle->_counts[(int)section])
 162                 RETERR(ENODEV);
 163         if (rrnum < handle->_rrnum)
 164                 setsection(handle, section);
 165         if (rrnum > handle->_rrnum) {
 166                 b = ns_skiprr(handle->_msg_ptr, handle->_eom, section,
 167                               rrnum - handle->_rrnum);
 168
 169                 if (b < 0)
 170                         return (-1);
 171                 handle->_msg_ptr += b;
 172                 handle->_rrnum = rrnum;
 173         }
 174
 175         /* Do the parse. */
 176         b = dn_expand(handle->_msg, handle->_eom,
 177                       handle->_msg_ptr, rr->name, NS_MAXDNAME);
 178         if (b < 0)
 179                 return (-1);
 180         handle->_msg_ptr += b;
 181         if (handle->_msg_ptr + NS_INT16SZ + NS_INT16SZ > handle->_eom)
 182                 RETERR(EMSGSIZE);
 183         NS_GET16(rr->type, handle->_msg_ptr);
 184         NS_GET16(rr->rr_class, handle->_msg_ptr);
 185         if (section == ns_s_qd) {
 186                 rr->ttl = 0;
 187                 rr->rdlength = 0;
 188                 rr->rdata = NULL;
 189         } else {
 190                 if (handle->_msg_ptr + NS_INT32SZ + NS_INT16SZ > handle->_eom)
 191                         RETERR(EMSGSIZE);
 192                 NS_GET32(rr->ttl, handle->_msg_ptr);
 193                 NS_GET16(rr->rdlength, handle->_msg_ptr);
 194                 if (handle->_msg_ptr + rr->rdlength > handle->_eom)
 195                         RETERR(EMSGSIZE);
 196                 rr->rdata = handle->_msg_ptr;
 197                 handle->_msg_ptr += rr->rdlength;
 198         }
 199         if (++handle->_rrnum > handle->_counts[(int)section])
 200                 setsection(handle, (ns_sect)((int)section + 1));
 201
 202         /* All done. */
 203         return (0);
 204 }
 205
 206 /*
 207  * This is identical to the above but uses network-format (uncompressed) names.
 208  */
 209 int
 210 ns_parserr2(ns_msg *handle, ns_sect section, int rrnum, ns_rr2 *rr) {
 211         int b;
 212         int tmp;
 213
 214         /* Make section right. */
 215         tmp = section;
 216         if (tmp < 0 || section >= ns_s_max)
 217                 RETERR(ENODEV);
 218         if (section != handle->_sect)
 219                 setsection(handle, section);
 220
 221         /* Make rrnum right. */
 222         if (rrnum == -1)
 223                 rrnum = handle->_rrnum;
 224         if (rrnum < 0 || rrnum >= handle->_counts[(int)section])
 225                 RETERR(ENODEV);
 226         if (rrnum < handle->_rrnum)
 227                 setsection(handle, section);
 228         if (rrnum > handle->_rrnum) {
 229                 b = ns_skiprr(handle->_msg_ptr, handle->_eom, section,
 230                               rrnum - handle->_rrnum);
 231
 232                 if (b < 0)
 233                         return (-1);
 234                 handle->_msg_ptr += b;
 235                 handle->_rrnum = rrnum;
 236         }
 237
 238         /* Do the parse. */
 239         b = ns_name_unpack2(handle->_msg, handle->_eom, handle->_msg_ptr,
 240                             rr->nname, NS_MAXNNAME, &rr->nnamel);
 241         if (b < 0)
 242                 return (-1);
 243         handle->_msg_ptr += b;
 244         if (handle->_msg_ptr + NS_INT16SZ + NS_INT16SZ > handle->_eom)
 245                 RETERR(EMSGSIZE);
 246         NS_GET16(rr->type, handle->_msg_ptr);
 247         NS_GET16(rr->rr_class, handle->_msg_ptr);
 248         if (section == ns_s_qd) {
 249                 rr->ttl = 0;
 250                 rr->rdlength = 0;
 251                 rr->rdata = NULL;
 252         } else {
 253                 if (handle->_msg_ptr + NS_INT32SZ + NS_INT16SZ > handle->_eom)
 254                         RETERR(EMSGSIZE);
 255                 NS_GET32(rr->ttl, handle->_msg_ptr);
 256                 NS_GET16(rr->rdlength, handle->_msg_ptr);
 257                 if (handle->_msg_ptr + rr->rdlength > handle->_eom)
 258                         RETERR(EMSGSIZE);
 259                 rr->rdata = handle->_msg_ptr;
 260                 handle->_msg_ptr += rr->rdlength;
 261         }
 262         if (++handle->_rrnum > handle->_counts[(int)section])
 263                 setsection(handle, (ns_sect)((int)section + 1));
 264
 265         /* All done. */
 266         return (0);
 267 }
 268
 269 /* Private. */
 270
 271 static void
 272 setsection(ns_msg *msg, ns_sect sect) {
 273         msg->_sect = sect;
 274         if (sect == ns_s_max) {
 275                 msg->_rrnum = -1;
 276                 msg->_msg_ptr = NULL;
 277         } else {
 278                 msg->_rrnum = 0;
 279                 msg->_msg_ptr = msg->_sections[(int)sect];
 280         }
 281 }
 282
 283 /*! \file */