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 */ 280