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