lib/libc/nameser/ns_parse.c

   1 /*      $NetBSD: ns_parse.c,v 1.9 2012/03/13 21:13:39 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 1.9 2012/03/13 21:13:39 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 <assert.h>
  39 #include <errno.h>
  40 #include <resolv.h>
  41 #include <string.h>
  42
  43 #include "port_after.h"
  44
  45 /* Forward. */
  46
  47 static void     setsection(ns_msg *msg, ns_sect sect);
  48
  49 /* Macros. */
  50
  51 #if !defined(SOLARIS2) || defined(__COVERITY__)
  52 #define RETERR(err) do { errno = (err); return (-1); } while (/*NOTREACHED*//*CONSTCOND*/0)
  53 #else
  54 #define RETERR(err) \
  55         do { errno = (err); if (errno == errno) return (-1); } while (0)
  56 #endif
  57
  58 #define PARSE_FMT_PRESO 0       /* Parse using presentation-format names */
  59 #define PARSE_FMT_WIRE 1        /* Parse using network-format names */
  60
  61 /* Public. */
  62
  63 /* These need to be in the same order as the nres.h:ns_flag enum. */
  64 struct _ns_flagdata _ns_flagdata[16] = {
  65         { 0x8000, 15 },         /*%< qr. */
  66         { 0x7800, 11 },         /*%< opcode. */
  67         { 0x0400, 10 },         /*%< aa. */
  68         { 0x0200, 9 },          /*%< tc. */
  69         { 0x0100, 8 },          /*%< rd. */
  70         { 0x0080, 7 },          /*%< ra. */
  71         { 0x0040, 6 },          /*%< z. */
  72         { 0x0020, 5 },          /*%< ad. */
  73         { 0x0010, 4 },          /*%< cd. */
  74         { 0x000f, 0 },          /*%< rcode. */
  75         { 0x0000, 0 },          /*%< expansion (1/6). */
  76         { 0x0000, 0 },          /*%< expansion (2/6). */
  77         { 0x0000, 0 },          /*%< expansion (3/6). */
  78         { 0x0000, 0 },          /*%< expansion (4/6). */
  79         { 0x0000, 0 },          /*%< expansion (5/6). */
  80         { 0x0000, 0 },          /*%< expansion (6/6). */
  81 };
  82
  83 int ns_msg_getflag(ns_msg handle, int flag) {
  84         return((u_int32_t)((handle)._flags & _ns_flagdata[flag].mask) >> _ns_flagdata[flag].shift);
  85 }
  86
  87 int
  88 ns_skiprr(const u_char *ptr, const u_char *eom, ns_sect section, int count) {
  89         const u_char *optr = ptr;
  90
  91         for (; count > 0; count--) {
  92                 int b, rdlength;
  93
  94                 b = dn_skipname(ptr, eom);
  95                 if (b < 0)
  96                         RETERR(EMSGSIZE);
  97                 ptr += b/*Name*/ + NS_INT16SZ/*Type*/ + NS_INT16SZ/*Class*/;
  98                 if (section != ns_s_qd) {
  99                         if (ptr + NS_INT32SZ + NS_INT16SZ > eom)
 100                                 RETERR(EMSGSIZE);
 101                         ptr += NS_INT32SZ/*TTL*/;
 102                         NS_GET16(rdlength, ptr);
 103                         ptr += rdlength/*RData*/;
 104                 }
 105         }
 106         if (ptr > eom)
 107                 RETERR(EMSGSIZE);
 108         _DIAGASSERT(__type_fit(int, ptr - optr));
 109         return (int)(ptr - optr);
 110 }
 111
 112 int
 113 ns_initparse(const u_char *msg, int msglen, ns_msg *handle) {
 114         const u_char *eom = msg + msglen;
 115         int i;
 116
 117         handle->_msg = msg;
 118         handle->_eom = eom;
 119         if (msg + NS_INT16SZ > eom)
 120                 RETERR(EMSGSIZE);
 121         NS_GET16(handle->_id, msg);
 122         if (msg + NS_INT16SZ > eom)
 123                 RETERR(EMSGSIZE);
 124         NS_GET16(handle->_flags, msg);
 125         for (i = 0; i < ns_s_max; i++) {
 126                 if (msg + NS_INT16SZ > eom)
 127                         RETERR(EMSGSIZE);
 128                 NS_GET16(handle->_counts[i], msg);
 129         }
 130         for (i = 0; i < ns_s_max; i++)
 131                 if (handle->_counts[i] == 0)
 132                         handle->_sections[i] = NULL;
 133                 else {
 134                         int b = ns_skiprr(msg, eom, (ns_sect)i,
 135                                           handle->_counts[i]);
 136
 137                         if (b < 0)
 138                                 return (-1);
 139                         handle->_sections[i] = msg;
 140                         msg += b;
 141                 }
 142         if (msg != eom)
 143                 RETERR(EMSGSIZE);
 144         setsection(handle, ns_s_max);
 145         return (0);
 146 }
 147
 148 int
 149 ns_parserr(ns_msg *handle, ns_sect section, int rrnum, ns_rr *rr) {
 150         int b;
 151         int tmp;
 152
 153         /* Make section right. */
 154         tmp = section;
 155         if (tmp < 0 || section >= ns_s_max)
 156                 RETERR(ENODEV);
 157         if (section != handle->_sect)
 158                 setsection(handle, section);
 159
 160         /* Make rrnum right. */
 161         if (rrnum == -1)
 162                 rrnum = handle->_rrnum;
 163         if (rrnum < 0 || rrnum >= handle->_counts[(int)section])
 164                 RETERR(ENODEV);
 165         if (rrnum < handle->_rrnum)
 166                 setsection(handle, section);
 167         if (rrnum > handle->_rrnum) {
 168                 b = ns_skiprr(handle->_msg_ptr, handle->_eom, section,
 169                               rrnum - handle->_rrnum);
 170
 171                 if (b < 0)
 172                         return (-1);
 173                 handle->_msg_ptr += b;
 174                 handle->_rrnum = rrnum;
 175         }
 176
 177         /* Do the parse. */
 178         b = dn_expand(handle->_msg, handle->_eom,
 179                       handle->_msg_ptr, rr->name, NS_MAXDNAME);
 180         if (b < 0)
 181                 return (-1);
 182         handle->_msg_ptr += b;
 183         if (handle->_msg_ptr + NS_INT16SZ + NS_INT16SZ > handle->_eom)
 184                 RETERR(EMSGSIZE);
 185         NS_GET16(rr->type, handle->_msg_ptr);
 186         NS_GET16(rr->rr_class, handle->_msg_ptr);
 187         if (section == ns_s_qd) {
 188                 rr->ttl = 0;
 189                 rr->rdlength = 0;
 190                 rr->rdata = NULL;
 191         } else {
 192                 if (handle->_msg_ptr + NS_INT32SZ + NS_INT16SZ > handle->_eom)
 193                         RETERR(EMSGSIZE);
 194                 NS_GET32(rr->ttl, handle->_msg_ptr);
 195                 NS_GET16(rr->rdlength, handle->_msg_ptr);
 196                 if (handle->_msg_ptr + rr->rdlength > handle->_eom)
 197                         RETERR(EMSGSIZE);
 198                 rr->rdata = handle->_msg_ptr;
 199                 handle->_msg_ptr += rr->rdlength;
 200         }
 201         if (++handle->_rrnum > handle->_counts[(int)section])
 202                 setsection(handle, (ns_sect)((int)section + 1));
 203
 204         /* All done. */
 205         return (0);
 206 }
 207
 208 /*
 209  * This is identical to the above but uses network-format (uncompressed) names.
 210  */
 211 int
 212 ns_parserr2(ns_msg *handle, ns_sect section, int rrnum, ns_rr2 *rr) {
 213         int b;
 214         int tmp;
 215
 216         /* Make section right. */
 217         tmp = section;
 218         if (tmp < 0 || section >= ns_s_max)
 219                 RETERR(ENODEV);
 220         if (section != handle->_sect)
 221                 setsection(handle, section);
 222
 223         /* Make rrnum right. */
 224         if (rrnum == -1)
 225                 rrnum = handle->_rrnum;
 226         if (rrnum < 0 || rrnum >= handle->_counts[(int)section])
 227                 RETERR(ENODEV);
 228         if (rrnum < handle->_rrnum)
 229                 setsection(handle, section);
 230         if (rrnum > handle->_rrnum) {
 231                 b = ns_skiprr(handle->_msg_ptr, handle->_eom, section,
 232                               rrnum - handle->_rrnum);
 233
 234                 if (b < 0)
 235                         return (-1);
 236                 handle->_msg_ptr += b;
 237                 handle->_rrnum = rrnum;
 238         }
 239
 240         /* Do the parse. */
 241         b = ns_name_unpack2(handle->_msg, handle->_eom, handle->_msg_ptr,
 242                             rr->nname, NS_MAXNNAME, &rr->nnamel);
 243         if (b < 0)
 244                 return (-1);
 245         handle->_msg_ptr += b;
 246         if (handle->_msg_ptr + NS_INT16SZ + NS_INT16SZ > handle->_eom)
 247                 RETERR(EMSGSIZE);
 248         NS_GET16(rr->type, handle->_msg_ptr);
 249         NS_GET16(rr->rr_class, handle->_msg_ptr);
 250         if (section == ns_s_qd) {
 251                 rr->ttl = 0;
 252                 rr->rdlength = 0;
 253                 rr->rdata = NULL;
 254         } else {
 255                 if (handle->_msg_ptr + NS_INT32SZ + NS_INT16SZ > handle->_eom)
 256                         RETERR(EMSGSIZE);
 257                 NS_GET32(rr->ttl, handle->_msg_ptr);
 258                 NS_GET16(rr->rdlength, handle->_msg_ptr);
 259                 if (handle->_msg_ptr + rr->rdlength > handle->_eom)
 260                         RETERR(EMSGSIZE);
 261                 rr->rdata = handle->_msg_ptr;
 262                 handle->_msg_ptr += rr->rdlength;
 263         }
 264         if (++handle->_rrnum > handle->_counts[(int)section])
 265                 setsection(handle, (ns_sect)((int)section + 1));
 266
 267         /* All done. */
 268         return (0);
 269 }
 270
 271 /* Private. */
 272
 273 static void
 274 setsection(ns_msg *msg, ns_sect sect) {
 275         msg->_sect = sect;
 276         if (sect == ns_s_max) {
 277                 msg->_rrnum = -1;
 278                 msg->_msg_ptr = NULL;
 279         } else {
 280                 msg->_rrnum = 0;
 281                 msg->_msg_ptr = msg->_sections[(int)sect];
 282         }
 283 }
 284
 285 /*! \file */