ns_parse.c revision 270838
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 19static 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: stable/10/lib/libc/nameser/ns_parse.c 270838 2014-08-30 10:16:25Z ume $"); 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 41static 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. */ 58struct _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 77int ns_msg_getflag(ns_msg handle, int flag) { 78 return(((handle)._flags & _ns_flagdata[flag].mask) >> _ns_flagdata[flag].shift); 79} 80 81int 82ns_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 105int 106ns_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 141int 142ns_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 */ 204int 205ns_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 265static void 266setsection(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 */ 278