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