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