1 /* $OpenBSD: parse.c,v 1.7 2004/09/16 18:35:43 deraadt 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 == RBRACE) { 71 if (brace_count) { 72 token = next_token(&val, cfile); 73 if (!--brace_count) 74 return; 75 } else 76 return; 77 } else if (token == LBRACE) { 78 brace_count++; 79 } else if (token == SEMI && !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 != SEMI) { 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 != STRING) { 122 parse_warn("filename must be a string"); 123 skip_to_semi(cfile); 124 return (NULL); 125 } 126 s = malloc(strlen(val) + 1); 127 if (!s) 128 error("no memory for string %s.", val); 129 strlcpy(s, val, strlen(val) + 1); 130 131 if (!parse_semi(cfile)) 132 return (NULL); 133 return (s); 134 } 135 136 /* 137 * hostname :== identifier | hostname DOT identifier 138 */ 139 char * 140 parse_host_name(FILE *cfile) 141 { 142 char *val, *s, *t; 143 int token, len = 0; 144 pair c = NULL; 145 146 /* Read a dotted hostname... */ 147 do { 148 /* Read a token, which should be an identifier. */ 149 token = next_token(&val, cfile); 150 if (!is_identifier(token) && token != NUMBER) { 151 parse_warn("expecting an identifier in hostname"); 152 skip_to_semi(cfile); 153 return (NULL); 154 } 155 /* Store this identifier... */ 156 if (!(s = malloc(strlen(val) + 1))) 157 error("can't allocate temp space for hostname."); 158 strlcpy(s, val, strlen(val) + 1); 159 c = cons((caddr_t) s, c); 160 len += strlen(s) + 1; 161 /* 162 * Look for a dot; if it's there, keep going, otherwise 163 * we're done. 164 */ 165 token = peek_token(&val, cfile); 166 if (token == DOT) 167 token = next_token(&val, cfile); 168 } while (token == DOT); 169 170 /* Assemble the hostname together into a string. */ 171 if (!(s = malloc(len))) 172 error("can't allocate space for hostname."); 173 t = s + len; 174 *--t = '\0'; 175 while (c) { 176 pair cdr = c->cdr; 177 int l = strlen((char *)c->car); 178 179 t -= l; 180 memcpy(t, (char *)c->car, l); 181 /* Free up temp space. */ 182 free(c->car); 183 free(c); 184 c = cdr; 185 if (t != s) 186 *--t = '.'; 187 } 188 return (s); 189 } 190 191 /* 192 * hardware-parameter :== HARDWARE ETHERNET csns SEMI 193 * csns :== NUMBER | csns COLON NUMBER 194 */ 195 void 196 parse_hardware_param(FILE *cfile, struct hardware *hardware) 197 { 198 char *val; 199 int token, hlen; 200 unsigned char *t; 201 202 token = next_token(&val, cfile); 203 switch (token) { 204 case ETHERNET: 205 hardware->htype = HTYPE_ETHER; 206 break; 207 case TOKEN_RING: 208 hardware->htype = HTYPE_IEEE802; 209 break; 210 case FDDI: 211 hardware->htype = HTYPE_FDDI; 212 break; 213 default: 214 parse_warn("expecting a network hardware type"); 215 skip_to_semi(cfile); 216 return; 217 } 218 219 /* 220 * Parse the hardware address information. Technically, it 221 * would make a lot of sense to restrict the length of the data 222 * we'll accept here to the length of a particular hardware 223 * address type. Unfortunately, there are some broken clients 224 * out there that put bogus data in the chaddr buffer, and we 225 * accept that data in the lease file rather than simply failing 226 * on such clients. Yuck. 227 */ 228 hlen = 0; 229 t = parse_numeric_aggregate(cfile, NULL, &hlen, COLON, 16, 8); 230 if (!t) 231 return; 232 if (hlen > sizeof(hardware->haddr)) { 233 free(t); 234 parse_warn("hardware address too long"); 235 } else { 236 hardware->hlen = hlen; 237 memcpy((unsigned char *)&hardware->haddr[0], t, hardware->hlen); 238 if (hlen < sizeof(hardware->haddr)) 239 memset(&hardware->haddr[hlen], 0, 240 sizeof(hardware->haddr) - hlen); 241 free(t); 242 } 243 244 token = next_token(&val, cfile); 245 if (token != SEMI) { 246 parse_warn("expecting semicolon."); 247 skip_to_semi(cfile); 248 } 249 } 250 251 /* 252 * lease-time :== NUMBER SEMI 253 */ 254 void 255 parse_lease_time(FILE *cfile, time_t *timep) 256 { 257 char *val; 258 int token; 259 260 token = next_token(&val, cfile); 261 if (token != NUMBER) { 262 parse_warn("Expecting numeric lease time"); 263 skip_to_semi(cfile); 264 return; 265 } 266 convert_num((unsigned char *)timep, val, 10, 32); 267 /* Unswap the number - convert_num returns stuff in NBO. */ 268 *timep = ntohl(*timep); /* XXX */ 269 270 parse_semi(cfile); 271 } 272 273 /* 274 * No BNF for numeric aggregates - that's defined by the caller. What 275 * this function does is to parse a sequence of numbers separated by the 276 * token specified in separator. If max is zero, any number of numbers 277 * will be parsed; otherwise, exactly max numbers are expected. Base 278 * and size tell us how to internalize the numbers once they've been 279 * tokenized. 280 */ 281 unsigned char * 282 parse_numeric_aggregate(FILE *cfile, unsigned char *buf, int *max, 283 int separator, int base, int size) 284 { 285 char *val, *t; 286 int token, count = 0; 287 unsigned char *bufp = buf, *s = NULL; 288 pair c = NULL; 289 290 if (!bufp && *max) { 291 bufp = malloc(*max * size / 8); 292 if (!bufp) 293 error("can't allocate space for numeric aggregate"); 294 } else 295 s = bufp; 296 297 do { 298 if (count) { 299 token = peek_token(&val, cfile); 300 if (token != separator) { 301 if (!*max) 302 break; 303 if (token != RBRACE && token != LBRACE) 304 token = next_token(&val, cfile); 305 parse_warn("too few numbers."); 306 if (token != SEMI) 307 skip_to_semi(cfile); 308 return (NULL); 309 } 310 token = next_token(&val, cfile); 311 } 312 token = next_token(&val, cfile); 313 314 if (token == EOF) { 315 parse_warn("unexpected end of file"); 316 break; 317 } 318 /* Allow NUMBER_OR_NAME if base is 16. */ 319 if (token != NUMBER && 320 (base != 16 || token != NUMBER_OR_NAME)) { 321 parse_warn("expecting numeric value."); 322 skip_to_semi(cfile); 323 return (NULL); 324 } 325 /* 326 * If we can, convert the number now; otherwise, build a 327 * linked list of all the numbers. 328 */ 329 if (s) { 330 convert_num(s, val, base, size); 331 s += size / 8; 332 } else { 333 t = malloc(strlen(val) + 1); 334 if (!t) 335 error("no temp space for number."); 336 strlcpy(t, val, strlen(val) + 1); 337 c = cons(t, c); 338 } 339 } while (++count != *max); 340 341 /* If we had to cons up a list, convert it now. */ 342 if (c) { 343 bufp = malloc(count * size / 8); 344 if (!bufp) 345 error("can't allocate space for numeric aggregate."); 346 s = bufp + count - size / 8; 347 *max = count; 348 } 349 while (c) { 350 pair cdr = c->cdr; 351 convert_num(s, (char *)c->car, base, size); 352 s -= size / 8; 353 /* Free up temp space. */ 354 free(c->car); 355 free(c); 356 c = cdr; 357 } 358 return (bufp); 359 } 360 361 void 362 convert_num(unsigned char *buf, char *str, int base, int size) 363 { 364 int negative = 0, tval, max; 365 char *ptr = str; 366 u_int32_t val = 0; 367 368 if (*ptr == '-') { 369 negative = 1; 370 ptr++; 371 } 372 /* If base wasn't specified, figure it out from the data. */ 373 if (!base) { 374 if (ptr[0] == '0') { 375 if (ptr[1] == 'x') { 376 base = 16; 377 ptr += 2; 378 } else if (isascii(ptr[1]) && isdigit(ptr[1])) { 379 base = 8; 380 ptr += 1; 381 } else 382 base = 10; 383 } else 384 base = 10; 385 } 386 do { 387 tval = *ptr++; 388 /* XXX assumes ASCII... */ 389 if (tval >= 'a') 390 tval = tval - 'a' + 10; 391 else if (tval >= 'A') 392 tval = tval - 'A' + 10; 393 else if (tval >= '0') 394 tval -= '0'; 395 else { 396 warning("Bogus number: %s.", str); 397 break; 398 } 399 if (tval >= base) { 400 warning("Bogus number: %s: digit %d not in base %d", 401 str, tval, base); 402 break; 403 } 404 val = val * base + tval; 405 } while (*ptr); 406 407 if (negative) 408 max = (1 << (size - 1)); 409 else 410 max = (1 << (size - 1)) + ((1 << (size - 1)) - 1); 411 if (val > max) { 412 switch (base) { 413 case 8: 414 warning("value %s%o exceeds max (%d) for precision.", 415 negative ? "-" : "", val, max); 416 break; 417 case 16: 418 warning("value %s%x exceeds max (%d) for precision.", 419 negative ? "-" : "", val, max); 420 break; 421 default: 422 warning("value %s%u exceeds max (%d) for precision.", 423 negative ? "-" : "", val, max); 424 break; 425 } 426 } 427 if (negative) { 428 switch (size) { 429 case 8: 430 *buf = -(unsigned long)val; 431 break; 432 case 16: 433 putShort(buf, -(unsigned long)val); 434 break; 435 case 32: 436 putLong(buf, -(unsigned long)val); 437 break; 438 default: 439 warning("Unexpected integer size: %d", size); 440 break; 441 } 442 } else { 443 switch (size) { 444 case 8: 445 *buf = (u_int8_t)val; 446 break; 447 case 16: 448 putUShort(buf, (u_int16_t)val); 449 break; 450 case 32: 451 putULong(buf, val); 452 break; 453 default: 454 warning("Unexpected integer size: %d", size); 455 break; 456 } 457 } 458 } 459 460 /* 461 * date :== NUMBER NUMBER SLASH NUMBER SLASH NUMBER 462 * NUMBER COLON NUMBER COLON NUMBER SEMI 463 * 464 * Dates are always in GMT; first number is day of week; next is 465 * year/month/day; next is hours:minutes:seconds on a 24-hour 466 * clock. 467 */ 468 time_t 469 parse_date(FILE * cfile) 470 { 471 struct tm tm; 472 int guess, token; 473 char *val; 474 static int months[11] = {31, 59, 90, 120, 151, 181, 475 212, 243, 273, 304, 334}; 476 477 /* Day of week... */ 478 token = next_token(&val, cfile); 479 if (token != NUMBER) { 480 parse_warn("numeric day of week expected."); 481 if (token != SEMI) 482 skip_to_semi(cfile); 483 return (NULL); 484 } 485 tm.tm_wday = atoi(val); 486 487 /* Year... */ 488 token = next_token(&val, cfile); 489 if (token != NUMBER) { 490 parse_warn("numeric year expected."); 491 if (token != SEMI) 492 skip_to_semi(cfile); 493 return (NULL); 494 } 495 tm.tm_year = atoi(val); 496 if (tm.tm_year > 1900) 497 tm.tm_year -= 1900; 498 499 /* Slash separating year from month... */ 500 token = next_token(&val, cfile); 501 if (token != SLASH) { 502 parse_warn("expected slash separating year from month."); 503 if (token != SEMI) 504 skip_to_semi(cfile); 505 return (NULL); 506 } 507 /* Month... */ 508 token = next_token(&val, cfile); 509 if (token != NUMBER) { 510 parse_warn("numeric month expected."); 511 if (token != SEMI) 512 skip_to_semi(cfile); 513 return (NULL); 514 } 515 tm.tm_mon = atoi(val) - 1; 516 517 /* Slash separating month from day... */ 518 token = next_token(&val, cfile); 519 if (token != SLASH) { 520 parse_warn("expected slash separating month from day."); 521 if (token != SEMI) 522 skip_to_semi(cfile); 523 return (NULL); 524 } 525 /* Month... */ 526 token = next_token(&val, cfile); 527 if (token != NUMBER) { 528 parse_warn("numeric day of month expected."); 529 if (token != SEMI) 530 skip_to_semi(cfile); 531 return (NULL); 532 } 533 tm.tm_mday = atoi(val); 534 535 /* Hour... */ 536 token = next_token(&val, cfile); 537 if (token != NUMBER) { 538 parse_warn("numeric hour expected."); 539 if (token != SEMI) 540 skip_to_semi(cfile); 541 return (NULL); 542 } 543 tm.tm_hour = atoi(val); 544 545 /* Colon separating hour from minute... */ 546 token = next_token(&val, cfile); 547 if (token != COLON) { 548 parse_warn("expected colon separating hour from minute."); 549 if (token != SEMI) 550 skip_to_semi(cfile); 551 return (NULL); 552 } 553 /* Minute... */ 554 token = next_token(&val, cfile); 555 if (token != NUMBER) { 556 parse_warn("numeric minute expected."); 557 if (token != SEMI) 558 skip_to_semi(cfile); 559 return (NULL); 560 } 561 tm.tm_min = atoi(val); 562 563 /* Colon separating minute from second... */ 564 token = next_token(&val, cfile); 565 if (token != COLON) { 566 parse_warn("expected colon separating hour from minute."); 567 if (token != SEMI) 568 skip_to_semi(cfile); 569 return (NULL); 570 } 571 /* Minute... */ 572 token = next_token(&val, cfile); 573 if (token != NUMBER) { 574 parse_warn("numeric minute expected."); 575 if (token != SEMI) 576 skip_to_semi(cfile); 577 return (NULL); 578 } 579 tm.tm_sec = atoi(val); 580 tm.tm_isdst = 0; 581 582 /* XXX: We assume that mktime does not use tm_yday. */ 583 tm.tm_yday = 0; 584 585 /* Make sure the date ends in a semicolon... */ 586 token = next_token(&val, cfile); 587 if (token != SEMI) { 588 parse_warn("semicolon expected."); 589 skip_to_semi(cfile); 590 return (NULL); 591 } 592 /* Guess the time value... */ 593 guess = ((((((365 * (tm.tm_year - 70) + /* Days in years since '70 */ 594 (tm.tm_year - 69) / 4 + /* Leap days since '70 */ 595 (tm.tm_mon /* Days in months this year */ 596 ? months[tm.tm_mon - 1] : 0) + 597 (tm.tm_mon > 1 && /* Leap day this year */ 598 !((tm.tm_year - 72) & 3)) + 599 tm.tm_mday - 1) * 24) + /* Day of month */ 600 tm.tm_hour) * 60) + tm.tm_min) * 60) + tm.tm_sec; 601 602 /* 603 * This guess could be wrong because of leap seconds or other 604 * weirdness we don't know about that the system does. For 605 * now, we're just going to accept the guess, but at some point 606 * it might be nice to do a successive approximation here to get 607 * an exact value. Even if the error is small, if the server 608 * is restarted frequently (and thus the lease database is 609 * reread), the error could accumulate into something 610 * significant. 611 */ 612 return (guess); 613 } 614