1 /* $OpenBSD: parse.c,v 1.14 2013/04/17 19:26:10 krw Exp $ */ 2 3 /* Common parser code for dhcpd and dhclient. */ 4 5 /* 6 * Copyright (c) 1995, 1996, 1997, 1998 The Internet Software Consortium. 7 * All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of The Internet Software Consortium nor the names 19 * of its contributors may be used to endorse or promote products derived 20 * from this software without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM AND 23 * CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, 24 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 25 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 26 * DISCLAIMED. IN NO EVENT SHALL THE INTERNET SOFTWARE CONSORTIUM OR 27 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 28 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 29 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF 30 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 31 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 32 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 33 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * This software has been written for the Internet Software Consortium 37 * by Ted Lemon <mellon@fugue.com> in cooperation with Vixie 38 * Enterprises. To learn more about the Internet Software Consortium, 39 * see ``http://www.vix.com/isc''. To learn more about Vixie 40 * Enterprises, see ``http://www.vix.com''. 41 */ 42 43 #include "dhcpd.h" 44 #include "dhctoken.h" 45 46 /* 47 * Skip to the semicolon ending the current statement. If we encounter 48 * braces, the matching closing brace terminates the statement. If we 49 * encounter a right brace but haven't encountered a left brace, return 50 * leaving the brace in the token buffer for the caller. If we see a 51 * semicolon and haven't seen a left brace, return. This lets us skip 52 * over: 53 * 54 * statement; 55 * statement foo bar { } 56 * statement foo bar { statement { } } 57 * statement} 58 * 59 * ...et cetera. 60 */ 61 void 62 skip_to_semi(FILE *cfile) 63 { 64 int token; 65 char *val; 66 int brace_count = 0; 67 68 do { 69 token = peek_token(&val, cfile); 70 if (token == '}') { 71 if (brace_count) { 72 token = next_token(&val, cfile); 73 if (!--brace_count) 74 return; 75 } else 76 return; 77 } else if (token == '{') { 78 brace_count++; 79 } else if (token == ';' && !brace_count) { 80 token = next_token(&val, cfile); 81 return; 82 } else if (token == '\n') { 83 /* 84 * EOL only happens when parsing 85 * /etc/resolv.conf, and we treat it like a 86 * semicolon because the resolv.conf file is 87 * line-oriented. 88 */ 89 token = next_token(&val, cfile); 90 return; 91 } 92 token = next_token(&val, cfile); 93 } while (token != EOF); 94 } 95 96 int 97 parse_semi(FILE *cfile) 98 { 99 int token; 100 char *val; 101 102 token = next_token(&val, cfile); 103 if (token != ';') { 104 parse_warn("semicolon expected."); 105 skip_to_semi(cfile); 106 return (0); 107 } 108 return (1); 109 } 110 111 /* 112 * string-parameter :== STRING SEMI 113 */ 114 char * 115 parse_string(FILE *cfile) 116 { 117 char *val, *s; 118 int token; 119 120 token = next_token(&val, cfile); 121 if (token != TOK_STRING) { 122 parse_warn("filename must be a string"); 123 skip_to_semi(cfile); 124 return (NULL); 125 } 126 s = strdup(val); 127 if (s == NULL) 128 error("no memory for string %s.", val); 129 130 if (!parse_semi(cfile)) { 131 free(s); 132 return (NULL); 133 } 134 return (s); 135 } 136 137 /* 138 * hostname :== identifier | hostname DOT identifier 139 */ 140 char * 141 parse_host_name(FILE *cfile) 142 { 143 char *val, *s, *t; 144 int token, len = 0; 145 pair c = NULL; 146 147 /* Read a dotted hostname... */ 148 do { 149 /* Read a token, which should be an identifier. */ 150 token = next_token(&val, cfile); 151 if (!is_identifier(token) && token != TOK_NUMBER) { 152 parse_warn("expecting an identifier in hostname"); 153 skip_to_semi(cfile); 154 return (NULL); 155 } 156 /* Store this identifier... */ 157 s = strdup(val); 158 if (s == NULL) 159 error("can't allocate temp space for hostname."); 160 c = cons((caddr_t) s, c); 161 len += strlen(s) + 1; 162 /* 163 * Look for a dot; if it's there, keep going, otherwise 164 * we're done. 165 */ 166 token = peek_token(&val, cfile); 167 if (token == '.') 168 token = next_token(&val, cfile); 169 } while (token == '.'); 170 171 /* Assemble the hostname together into a string. */ 172 if (!(s = malloc(len))) 173 error("can't allocate space for hostname."); 174 t = s + len; 175 *--t = '\0'; 176 while (c) { 177 pair cdr = c->cdr; 178 int l = strlen((char *)c->car); 179 180 t -= l; 181 memcpy(t, (char *)c->car, l); 182 /* Free up temp space. */ 183 free(c->car); 184 free(c); 185 c = cdr; 186 if (t != s) 187 *--t = '.'; 188 } 189 return (s); 190 } 191 192 /* 193 * hardware-parameter :== HARDWARE ETHERNET csns SEMI 194 * csns :== NUMBER | csns COLON NUMBER 195 */ 196 void 197 parse_hardware_param(FILE *cfile, struct hardware *hardware) 198 { 199 char *val; 200 int token, hlen; 201 unsigned char *t; 202 203 token = next_token(&val, cfile); 204 switch (token) { 205 case TOK_ETHERNET: 206 hardware->htype = HTYPE_ETHER; 207 break; 208 case TOK_TOKEN_RING: 209 hardware->htype = HTYPE_IEEE802; 210 break; 211 case TOK_FDDI: 212 hardware->htype = HTYPE_FDDI; 213 break; 214 case TOK_IPSEC_TUNNEL: 215 hardware->htype = HTYPE_IPSEC_TUNNEL; 216 break; 217 default: 218 parse_warn("expecting a network hardware type"); 219 skip_to_semi(cfile); 220 return; 221 } 222 223 /* 224 * Parse the hardware address information. Technically, it 225 * would make a lot of sense to restrict the length of the data 226 * we'll accept here to the length of a particular hardware 227 * address type. Unfortunately, there are some broken clients 228 * out there that put bogus data in the chaddr buffer, and we 229 * accept that data in the lease file rather than simply failing 230 * on such clients. Yuck. 231 */ 232 hlen = 0; 233 t = parse_numeric_aggregate(cfile, NULL, &hlen, ':', 16, 8); 234 if (!t) 235 return; 236 if (hlen > sizeof(hardware->haddr)) { 237 free(t); 238 parse_warn("hardware address too long"); 239 } else { 240 hardware->hlen = hlen; 241 memcpy((unsigned char *)&hardware->haddr[0], t, hardware->hlen); 242 if (hlen < sizeof(hardware->haddr)) 243 memset(&hardware->haddr[hlen], 0, 244 sizeof(hardware->haddr) - hlen); 245 free(t); 246 } 247 248 token = next_token(&val, cfile); 249 if (token != ';') { 250 parse_warn("expecting semicolon."); 251 skip_to_semi(cfile); 252 } 253 } 254 255 /* 256 * lease-time :== NUMBER SEMI 257 */ 258 void 259 parse_lease_time(FILE *cfile, time_t *timep) 260 { 261 char *val; 262 uint32_t value; 263 int token; 264 265 token = next_token(&val, cfile); 266 if (token != TOK_NUMBER) { 267 parse_warn("Expecting numeric lease time"); 268 skip_to_semi(cfile); 269 return; 270 } 271 convert_num((unsigned char *)&value, val, 10, 32); 272 /* Unswap the number - convert_num returns stuff in NBO. */ 273 *timep = ntohl(value); /* XXX */ 274 275 parse_semi(cfile); 276 } 277 278 /* 279 * No BNF for numeric aggregates - that's defined by the caller. What 280 * this function does is to parse a sequence of numbers separated by the 281 * token specified in separator. If max is zero, any number of numbers 282 * will be parsed; otherwise, exactly max numbers are expected. Base 283 * and size tell us how to internalize the numbers once they've been 284 * tokenized. 285 */ 286 unsigned char * 287 parse_numeric_aggregate(FILE *cfile, unsigned char *buf, int *max, 288 int separator, int base, int size) 289 { 290 char *val, *t; 291 int token, count = 0; 292 unsigned char *bufp = buf, *s = NULL; 293 pair c = NULL; 294 295 if (!bufp && *max) { 296 bufp = malloc(*max * size / 8); 297 if (!bufp) 298 error("can't allocate space for numeric aggregate"); 299 } else 300 s = bufp; 301 302 do { 303 if (count) { 304 token = peek_token(&val, cfile); 305 if (token != separator) { 306 if (!*max) 307 break; 308 if (token != '{' && token != '}') 309 token = next_token(&val, cfile); 310 parse_warn("too few numbers."); 311 if (token != ';') 312 skip_to_semi(cfile); 313 return (NULL); 314 } 315 token = next_token(&val, cfile); 316 } 317 token = next_token(&val, cfile); 318 319 if (token == EOF) { 320 parse_warn("unexpected end of file"); 321 break; 322 } 323 /* Allow NUMBER_OR_NAME if base is 16. */ 324 if (token != TOK_NUMBER && 325 (base != 16 || token != TOK_NUMBER_OR_NAME)) { 326 parse_warn("expecting numeric value."); 327 skip_to_semi(cfile); 328 return (NULL); 329 } 330 /* 331 * If we can, convert the number now; otherwise, build a 332 * linked list of all the numbers. 333 */ 334 if (s) { 335 convert_num(s, val, base, size); 336 s += size / 8; 337 } else { 338 t = strdup(val); 339 if (t == NULL) 340 error("no temp space for number."); 341 c = cons(t, c); 342 } 343 } while (++count != *max); 344 345 /* If we had to cons up a list, convert it now. */ 346 if (c) { 347 bufp = malloc(count * size / 8); 348 if (!bufp) 349 error("can't allocate space for numeric aggregate."); 350 s = bufp + count - size / 8; 351 *max = count; 352 } 353 while (c) { 354 pair cdr = c->cdr; 355 convert_num(s, (char *)c->car, base, size); 356 s -= size / 8; 357 /* Free up temp space. */ 358 free(c->car); 359 free(c); 360 c = cdr; 361 } 362 return (bufp); 363 } 364 365 void 366 convert_num(unsigned char *buf, char *str, int base, int size) 367 { 368 int negative = 0, tval, max; 369 u_int32_t val = 0; 370 char *ptr = str; 371 372 if (*ptr == '-') { 373 negative = 1; 374 ptr++; 375 } 376 377 /* If base wasn't specified, figure it out from the data. */ 378 if (!base) { 379 if (ptr[0] == '0') { 380 if (ptr[1] == 'x') { 381 base = 16; 382 ptr += 2; 383 } else if (isascii(ptr[1]) && isdigit(ptr[1])) { 384 base = 8; 385 ptr += 1; 386 } else 387 base = 10; 388 } else 389 base = 10; 390 } 391 392 do { 393 tval = *ptr++; 394 /* XXX assumes ASCII... */ 395 if (tval >= 'a') 396 tval = tval - 'a' + 10; 397 else if (tval >= 'A') 398 tval = tval - 'A' + 10; 399 else if (tval >= '0') 400 tval -= '0'; 401 else { 402 warning("Bogus number: %s.", str); 403 break; 404 } 405 if (tval >= base) { 406 warning("Bogus number: %s: digit %d not in base %d", 407 str, tval, base); 408 break; 409 } 410 val = val * base + tval; 411 } while (*ptr); 412 413 if (negative) 414 max = (1 << (size - 1)); 415 else 416 max = (1 << (size - 1)) + ((1 << (size - 1)) - 1); 417 if (val > max) { 418 switch (base) { 419 case 8: 420 warning("value %s%o exceeds max (%d) for precision.", 421 negative ? "-" : "", val, max); 422 break; 423 case 16: 424 warning("value %s%x exceeds max (%d) for precision.", 425 negative ? "-" : "", val, max); 426 break; 427 default: 428 warning("value %s%u exceeds max (%d) for precision.", 429 negative ? "-" : "", val, max); 430 break; 431 } 432 } 433 434 if (negative) { 435 switch (size) { 436 case 8: 437 *buf = -(unsigned long)val; 438 break; 439 case 16: 440 putShort(buf, -(unsigned long)val); 441 break; 442 case 32: 443 putLong(buf, -(unsigned long)val); 444 break; 445 default: 446 warning("Unexpected integer size: %d", size); 447 break; 448 } 449 } else { 450 switch (size) { 451 case 8: 452 *buf = (u_int8_t)val; 453 break; 454 case 16: 455 putUShort(buf, (u_int16_t)val); 456 break; 457 case 32: 458 putULong(buf, val); 459 break; 460 default: 461 warning("Unexpected integer size: %d", size); 462 break; 463 } 464 } 465 } 466 467 /* 468 * date :== NUMBER NUMBER SLASH NUMBER SLASH NUMBER 469 * NUMBER COLON NUMBER COLON NUMBER UTC SEMI 470 * 471 * Dates are always in UTC; first number is day of week; next is 472 * year/month/day; next is hours:minutes:seconds on a 24-hour 473 * clock. 474 */ 475 time_t 476 parse_date(FILE *cfile) 477 { 478 struct tm tm; 479 char timestr[26]; /* "w yyyy/mm/dd hh:mm:ss UTC" */ 480 char *val, *p; 481 size_t n; 482 time_t guess; 483 int token; 484 485 memset(timestr, 0, sizeof(timestr)); 486 487 do { 488 token = peek_token(NULL, cfile); 489 switch (token) { 490 case TOK_NAME: 491 case TOK_NUMBER: 492 case '/': 493 case ':': 494 token = next_token(&val, cfile); 495 n = strlcat(timestr, val, sizeof(timestr)); 496 if (n >= sizeof(timestr)) { 497 /* XXX Will break after year 9999! */ 498 parse_warn("time string too long"); 499 skip_to_semi(cfile); 500 return (0); 501 } 502 break; 503 case';': 504 break; 505 default: 506 parse_warn("invalid time string"); 507 skip_to_semi(cfile); 508 return (0); 509 } 510 } while (token != ';'); 511 512 parse_semi(cfile); 513 514 memset(&tm, 0, sizeof(tm)); /* 'cuz strptime ignores tm_isdt. */ 515 p = strptime(timestr, DB_TIMEFMT, &tm); 516 if (p == NULL || *p != '\0') { 517 p = strptime(timestr, OLD_DB_TIMEFMT, &tm); 518 if (p == NULL || *p != '\0') { 519 parse_warn("unparseable time string"); 520 return (0); 521 } 522 } 523 524 guess = timegm(&tm); 525 if (guess == -1) { 526 parse_warn("time could not be represented"); 527 return (0); 528 } 529 530 return (guess); 531 } 532