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