lib/libc/nameser/ns_parse.c

   1 /*-
   2  * SPDX-License-Identifier: ISC
   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 #ifndef lint
  21 static const char rcsid[] = "$Id: ns_parse.c,v 1.10 2009/01/23 19:59:16 each Exp $";
  22 #endif
  23 #include <sys/cdefs.h>
  24 __FBSDID("$FreeBSD$");
  25
  26 /* Import. */
  27
  28 #include "port_before.h"
  29
  30 #include <sys/types.h>
  31
  32 #include <netinet/in.h>
  33 #include <arpa/nameser.h>
  34
  35 #include <errno.h>
  36 #include <resolv.h>
  37 #include <string.h>
  38
  39 #include "port_after.h"
  40
  41 /* Forward. */
  42
  43 static void     setsection(ns_msg *msg, ns_sect sect);
  44
  45 /* Macros. */
  46
  47 #if !defined(SOLARIS2) || defined(__COVERITY__)
  48 #define RETERR(err) do { errno = (err); return (-1); } while (0)
  49 #else
  50 #define RETERR(err) \
  51         do { errno = (err); if (errno == errno) return (-1); } while (0)
  52 #endif
  53
  54 #define PARSE_FMT_PRESO 0       /* Parse using presentation-format names */
  55 #define PARSE_FMT_WIRE 1        /* Parse using network-format names */
  56
  57 /* Public. */
  58
  59 /* These need to be in the same order as the nres.h:ns_flag enum. */
  60 struct _ns_flagdata _ns_flagdata[16] = {
  61         { 0x8000, 15 },         /*%< qr. */
  62         { 0x7800, 11 },         /*%< opcode. */
  63         { 0x0400, 10 },         /*%< aa. */
  64         { 0x0200, 9 },          /*%< tc. */
  65         { 0x0100, 8 },          /*%< rd. */
  66         { 0x0080, 7 },          /*%< ra. */
  67         { 0x0040, 6 },          /*%< z. */
  68         { 0x0020, 5 },          /*%< ad. */
  69         { 0x0010, 4 },          /*%< cd. */
  70         { 0x000f, 0 },          /*%< rcode. */
  71         { 0x0000, 0 },          /*%< expansion (1/6). */
  72         { 0x0000, 0 },          /*%< expansion (2/6). */
  73         { 0x0000, 0 },          /*%< expansion (3/6). */
  74         { 0x0000, 0 },          /*%< expansion (4/6). */
  75         { 0x0000, 0 },          /*%< expansion (5/6). */
  76         { 0x0000, 0 },          /*%< expansion (6/6). */
  77 };
  78
  79 int ns_msg_getflag(ns_msg handle, int flag) {
  80         return(((handle)._flags & _ns_flagdata[flag].mask) >> _ns_flagdata[flag].shift);
  81 }
  82
  83 int
  84 ns_skiprr(const u_char *ptr, const u_char *eom, ns_sect section, int count) {
  85         const u_char *optr = ptr;
  86
  87         for ((void)NULL; count > 0; count--) {
  88                 int b, rdlength;
  89
  90                 b = dn_skipname(ptr, eom);
  91                 if (b < 0)
  92                         RETERR(EMSGSIZE);
  93                 ptr += b/*Name*/ + NS_INT16SZ/*Type*/ + NS_INT16SZ/*Class*/;
  94                 if (section != ns_s_qd) {
  95                         if (ptr + NS_INT32SZ + NS_INT16SZ > eom)
  96                                 RETERR(EMSGSIZE);
  97                         ptr += NS_INT32SZ/*TTL*/;
  98                         NS_GET16(rdlength, ptr);
  99                         ptr += rdlength/*RData*/;
 100                 }
 101         }
 102         if (ptr > eom)
 103                 RETERR(EMSGSIZE);
 104         return (ptr - optr);
 105 }
 106
 107 int
 108 ns_initparse(const u_char *msg, int msglen, ns_msg *handle) {
 109         const u_char *eom = msg + msglen;
 110         int i;
 111
 112         handle->_msg = msg;
 113         handle->_eom = eom;
 114         if (msg + NS_INT16SZ > eom)
 115                 RETERR(EMSGSIZE);
 116         NS_GET16(handle->_id, msg);
 117         if (msg + NS_INT16SZ > eom)
 118                 RETERR(EMSGSIZE);
 119         NS_GET16(handle->_flags, msg);
 120         for (i = 0; i < ns_s_max; i++) {
 121                 if (msg + NS_INT16SZ > eom)
 122                         RETERR(EMSGSIZE);
 123                 NS_GET16(handle->_counts[i], msg);
 124         }
 125         for (i = 0; i < ns_s_max; i++)
 126                 if (handle->_counts[i] == 0)
 127                         handle->_sections[i] = NULL;
 128                 else {
 129                         int b = ns_skiprr(msg, eom, (ns_sect)i,
 130                                           handle->_counts[i]);
 131
 132                         if (b < 0)
 133                                 return (-1);
 134                         handle->_sections[i] = msg;
 135                         msg += b;
 136                 }
 137         if (msg != eom)
 138                 RETERR(EMSGSIZE);
 139         setsection(handle, ns_s_max);
 140         return (0);
 141 }
 142
 143 int
 144 ns_parserr(ns_msg *handle, ns_sect section, int rrnum, ns_rr *rr) {
 145         int b;
 146         int tmp;
 147
 148         /* Make section right. */
 149         tmp = section;
 150         if (tmp < 0 || section >= ns_s_max)
 151                 RETERR(ENODEV);
 152         if (section != handle->_sect)
 153                 setsection(handle, section);
 154
 155         /* Make rrnum right. */
 156         if (rrnum == -1)
 157                 rrnum = handle->_rrnum;
 158         if (rrnum < 0 || rrnum >= handle->_counts[(int)section])
 159                 RETERR(ENODEV);
 160         if (rrnum < handle->_rrnum)
 161                 setsection(handle, section);
 162         if (rrnum > handle->_rrnum) {
 163                 b = ns_skiprr(handle->_msg_ptr, handle->_eom, section,
 164                               rrnum - handle->_rrnum);
 165
 166                 if (b < 0)
 167                         return (-1);
 168                 handle->_msg_ptr += b;
 169                 handle->_rrnum = rrnum;
 170         }
 171
 172         /* Do the parse. */
 173         b = dn_expand(handle->_msg, handle->_eom,
 174                       handle->_msg_ptr, rr->name, NS_MAXDNAME);
 175         if (b < 0)
 176                 return (-1);
 177         handle->_msg_ptr += b;
 178         if (handle->_msg_ptr + NS_INT16SZ + NS_INT16SZ > handle->_eom)
 179                 RETERR(EMSGSIZE);
 180         NS_GET16(rr->type, handle->_msg_ptr);
 181         NS_GET16(rr->rr_class, handle->_msg_ptr);
 182         if (section == ns_s_qd) {
 183                 rr->ttl = 0;
 184                 rr->rdlength = 0;
 185                 rr->rdata = NULL;
 186         } else {
 187                 if (handle->_msg_ptr + NS_INT32SZ + NS_INT16SZ > handle->_eom)
 188                         RETERR(EMSGSIZE);
 189                 NS_GET32(rr->ttl, handle->_msg_ptr);
 190                 NS_GET16(rr->rdlength, handle->_msg_ptr);
 191                 if (handle->_msg_ptr + rr->rdlength > handle->_eom)
 192                         RETERR(EMSGSIZE);
 193                 rr->rdata = handle->_msg_ptr;
 194                 handle->_msg_ptr += rr->rdlength;
 195         }
 196         if (++handle->_rrnum > handle->_counts[(int)section])
 197                 setsection(handle, (ns_sect)((int)section + 1));
 198
 199         /* All done. */
 200         return (0);
 201 }
 202
 203 /*
 204  * This is identical to the above but uses network-format (uncompressed) names.
 205  */
 206 int
 207 ns_parserr2(ns_msg *handle, ns_sect section, int rrnum, ns_rr2 *rr) {
 208         int b;
 209         int tmp;
 210
 211         /* Make section right. */
 212         if ((tmp = section) < 0 || section >= ns_s_max)
 213                 RETERR(ENODEV);
 214         if (section != handle->_sect)
 215                 setsection(handle, section);
 216
 217         /* Make rrnum right. */
 218         if (rrnum == -1)
 219                 rrnum = handle->_rrnum;
 220         if (rrnum < 0 || rrnum >= handle->_counts[(int)section])
 221                 RETERR(ENODEV);
 222         if (rrnum < handle->_rrnum)
 223                 setsection(handle, section);
 224         if (rrnum > handle->_rrnum) {
 225                 b = ns_skiprr(handle->_msg_ptr, handle->_eom, section,
 226                               rrnum - handle->_rrnum);
 227
 228                 if (b < 0)
 229                         return (-1);
 230                 handle->_msg_ptr += b;
 231                 handle->_rrnum = rrnum;
 232         }
 233
 234         /* Do the parse. */
 235         b = ns_name_unpack2(handle->_msg, handle->_eom, handle->_msg_ptr,
 236                             rr->nname, NS_MAXNNAME, &rr->nnamel);
 237         if (b < 0)
 238                 return (-1);
 239         handle->_msg_ptr += b;
 240         if (handle->_msg_ptr + NS_INT16SZ + NS_INT16SZ > handle->_eom)
 241                 RETERR(EMSGSIZE);
 242         NS_GET16(rr->type, handle->_msg_ptr);
 243         NS_GET16(rr->rr_class, handle->_msg_ptr);
 244         if (section == ns_s_qd) {
 245                 rr->ttl = 0;
 246                 rr->rdlength = 0;
 247                 rr->rdata = NULL;
 248         } else {
 249                 if (handle->_msg_ptr + NS_INT32SZ + NS_INT16SZ > handle->_eom)
 250                         RETERR(EMSGSIZE);
 251                 NS_GET32(rr->ttl, handle->_msg_ptr);
 252                 NS_GET16(rr->rdlength, handle->_msg_ptr);
 253                 if (handle->_msg_ptr + rr->rdlength > handle->_eom)
 254                         RETERR(EMSGSIZE);
 255                 rr->rdata = handle->_msg_ptr;
 256                 handle->_msg_ptr += rr->rdlength;
 257         }
 258         if (++handle->_rrnum > handle->_counts[(int)section])
 259                 setsection(handle, (ns_sect)((int)section + 1));
 260
 261         /* All done. */
 262         return (0);
 263 }
 264
 265 /* Private. */
 266
 267 static void
 268 setsection(ns_msg *msg, ns_sect sect) {
 269         msg->_sect = sect;
 270         if (sect == ns_s_max) {
 271                 msg->_rrnum = -1;
 272                 msg->_msg_ptr = NULL;
 273         } else {
 274                 msg->_rrnum = 0;
 275                 msg->_msg_ptr = msg->_sections[(int)sect];
 276         }
 277 }
 278
 279 /*! \file */