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 * $Id: ns_parse.c,v 1.9 2007/08/27 03:32:26 marka Exp $ 18 */ 19 20 /* Import. */ 21 22 #include "port_before.h" 23 24 #include <sys/types.h> 25 26 #include <netinet/in.h> 27 #include <arpa/nameser.h> 28 29 #include <errno.h> 30 #include <resolv.h> 31 #include <string.h> 32 33 #include "port_after.h" 34 35 /* Forward. */ 36 37 static void setsection(ns_msg *msg, ns_sect sect); 38 39 /* Macros. */ 40 41 #if !defined(SOLARIS2) || defined(__COVERITY__) 42 #define RETERR(err) do { errno = (err); return (-1); } while (0) 43 #else 44 #define RETERR(err) \ 45 do { errno = (err); if (errno == errno) return (-1); } while (0) 46 #endif 47 48 /* Public. */ 49 50 /* These need to be in the same order as the nres.h:ns_flag enum. */ 51 struct _ns_flagdata _ns_flagdata[16] = { 52 { 0x8000, 15 }, /*%< qr. */ 53 { 0x7800, 11 }, /*%< opcode. */ 54 { 0x0400, 10 }, /*%< aa. */ 55 { 0x0200, 9 }, /*%< tc. */ 56 { 0x0100, 8 }, /*%< rd. */ 57 { 0x0080, 7 }, /*%< ra. */ 58 { 0x0040, 6 }, /*%< z. */ 59 { 0x0020, 5 }, /*%< ad. */ 60 { 0x0010, 4 }, /*%< cd. */ 61 { 0x000f, 0 }, /*%< rcode. */ 62 { 0x0000, 0 }, /*%< expansion (1/6). */ 63 { 0x0000, 0 }, /*%< expansion (2/6). */ 64 { 0x0000, 0 }, /*%< expansion (3/6). */ 65 { 0x0000, 0 }, /*%< expansion (4/6). */ 66 { 0x0000, 0 }, /*%< expansion (5/6). */ 67 { 0x0000, 0 }, /*%< expansion (6/6). */ 68 }; 69 70 int ns_msg_getflag(ns_msg handle, int flag) { 71 return(((handle)._flags & _ns_flagdata[flag].mask) >> _ns_flagdata[flag].shift); 72 } 73 74 int 75 ns_skiprr(const u_char *ptr, const u_char *eom, ns_sect section, int count) { 76 const u_char *optr = ptr; 77 78 for ((void)NULL; count > 0; count--) { 79 int b, rdlength; 80 81 b = dn_skipname(ptr, eom); 82 if (b < 0) 83 RETERR(EMSGSIZE); 84 ptr += b/*Name*/ + NS_INT16SZ/*Type*/ + NS_INT16SZ/*Class*/; 85 if (section != ns_s_qd) { 86 if (ptr + NS_INT32SZ + NS_INT16SZ > eom) 87 RETERR(EMSGSIZE); 88 ptr += NS_INT32SZ/*TTL*/; 89 NS_GET16(rdlength, ptr); 90 ptr += rdlength/*RData*/; 91 } 92 } 93 if (ptr > eom) 94 RETERR(EMSGSIZE); 95 return (ptr - optr); 96 } 97 98 int 99 ns_initparse(const u_char *msg, int msglen, ns_msg *handle) { 100 const u_char *eom = msg + msglen; 101 int i; 102 103 memset(handle, 0x5e, sizeof *handle); 104 handle->_msg = msg; 105 handle->_eom = eom; 106 if (msg + NS_INT16SZ > eom) 107 RETERR(EMSGSIZE); 108 NS_GET16(handle->_id, msg); 109 if (msg + NS_INT16SZ > eom) 110 RETERR(EMSGSIZE); 111 NS_GET16(handle->_flags, msg); 112 for (i = 0; i < ns_s_max; i++) { 113 if (msg + NS_INT16SZ > eom) 114 RETERR(EMSGSIZE); 115 NS_GET16(handle->_counts[i], msg); 116 } 117 for (i = 0; i < ns_s_max; i++) 118 if (handle->_counts[i] == 0) 119 handle->_sections[i] = NULL; 120 else { 121 int b = ns_skiprr(msg, eom, (ns_sect)i, 122 handle->_counts[i]); 123 124 if (b < 0) 125 return (-1); 126 handle->_sections[i] = msg; 127 msg += b; 128 } 129 if (msg != eom) 130 RETERR(EMSGSIZE); 131 setsection(handle, ns_s_max); 132 return (0); 133 } 134 135 int 136 ns_parserr(ns_msg *handle, ns_sect section, int rrnum, ns_rr *rr) { 137 int b; 138 int tmp; 139 140 /* Make section right. */ 141 tmp = section; 142 if (tmp < 0 || section >= ns_s_max) 143 RETERR(ENODEV); 144 if (section != handle->_sect) 145 setsection(handle, section); 146 147 /* Make rrnum right. */ 148 if (rrnum == -1) 149 rrnum = handle->_rrnum; 150 if (rrnum < 0 || rrnum >= handle->_counts[(int)section]) 151 RETERR(ENODEV); 152 if (rrnum < handle->_rrnum) 153 setsection(handle, section); 154 if (rrnum > handle->_rrnum) { 155 b = ns_skiprr(handle->_msg_ptr, handle->_eom, section, 156 rrnum - handle->_rrnum); 157 158 if (b < 0) 159 return (-1); 160 handle->_msg_ptr += b; 161 handle->_rrnum = rrnum; 162 } 163 164 /* Do the parse. */ 165 b = dn_expand(handle->_msg, handle->_eom, 166 handle->_msg_ptr, rr->name, NS_MAXDNAME); 167 if (b < 0) 168 return (-1); 169 handle->_msg_ptr += b; 170 if (handle->_msg_ptr + NS_INT16SZ + NS_INT16SZ > handle->_eom) 171 RETERR(EMSGSIZE); 172 NS_GET16(rr->type, handle->_msg_ptr); 173 NS_GET16(rr->rr_class, handle->_msg_ptr); 174 if (section == ns_s_qd) { 175 rr->ttl = 0; 176 rr->rdlength = 0; 177 rr->rdata = NULL; 178 } else { 179 if (handle->_msg_ptr + NS_INT32SZ + NS_INT16SZ > handle->_eom) 180 RETERR(EMSGSIZE); 181 NS_GET32(rr->ttl, handle->_msg_ptr); 182 NS_GET16(rr->rdlength, handle->_msg_ptr); 183 if (handle->_msg_ptr + rr->rdlength > handle->_eom) 184 RETERR(EMSGSIZE); 185 rr->rdata = handle->_msg_ptr; 186 handle->_msg_ptr += rr->rdlength; 187 } 188 if (++handle->_rrnum > handle->_counts[(int)section]) 189 setsection(handle, (ns_sect)((int)section + 1)); 190 191 /* All done. */ 192 return (0); 193 } 194 195 /* Private. */ 196 197 static void 198 setsection(ns_msg *msg, ns_sect sect) { 199 msg->_sect = sect; 200 if (sect == ns_s_max) { 201 msg->_rrnum = -1; 202 msg->_msg_ptr = NULL; 203 } else { 204 msg->_rrnum = 0; 205 msg->_msg_ptr = msg->_sections[(int)sect]; 206 } 207 } 208 209 /*! \file */ 210