1 /* $OpenBSD: parse.c,v 1.26 2017/02/16 00:24:43 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 <sys/types.h> 44 #include <sys/socket.h> 45 46 #include <net/if.h> 47 48 #include <netinet/in.h> 49 50 #include <ctype.h> 51 #include <errno.h> 52 #include <stdarg.h> 53 #include <stdint.h> 54 #include <stdio.h> 55 #include <stdlib.h> 56 #include <string.h> 57 #include <syslog.h> 58 #include <time.h> 59 #include <unistd.h> 60 61 #include "dhcp.h" 62 #include "tree.h" 63 #include "dhcpd.h" 64 #include "dhctoken.h" 65 #include "log.h" 66 67 /* 68 * Skip to the semicolon ending the current statement. If we encounter 69 * braces, the matching closing brace terminates the statement. If we 70 * encounter a right brace but haven't encountered a left brace, return 71 * leaving the brace in the token buffer for the caller. If we see a 72 * semicolon and haven't seen a left brace, return. This lets us skip 73 * over: 74 * 75 * statement; 76 * statement foo bar { } 77 * statement foo bar { statement { } } 78 * statement} 79 * 80 * ...et cetera. 81 */ 82 void 83 skip_to_semi(FILE *cfile) 84 { 85 int token; 86 char *val; 87 int brace_count = 0; 88 89 do { 90 token = peek_token(&val, cfile); 91 if (token == '}') { 92 if (brace_count) { 93 token = next_token(&val, cfile); 94 if (!--brace_count) 95 return; 96 } else 97 return; 98 } else if (token == '{') { 99 brace_count++; 100 } else if (token == ';' && !brace_count) { 101 token = next_token(&val, cfile); 102 return; 103 } else if (token == '\n') { 104 /* 105 * EOL only happens when parsing 106 * /etc/resolv.conf, and we treat it like a 107 * semicolon because the resolv.conf file is 108 * line-oriented. 109 */ 110 token = next_token(&val, cfile); 111 return; 112 } 113 token = next_token(&val, cfile); 114 } while (token != EOF); 115 } 116 117 int 118 parse_semi(FILE *cfile) 119 { 120 int token; 121 char *val; 122 123 token = next_token(&val, cfile); 124 if (token != ';') { 125 parse_warn("semicolon expected."); 126 skip_to_semi(cfile); 127 return (0); 128 } 129 return (1); 130 } 131 132 /* 133 * string-parameter :== STRING SEMI 134 */ 135 char * 136 parse_string(FILE *cfile) 137 { 138 char *val, *s; 139 int token; 140 141 token = next_token(&val, cfile); 142 if (token != TOK_STRING) { 143 parse_warn("filename must be a string"); 144 skip_to_semi(cfile); 145 return (NULL); 146 } 147 s = strdup(val); 148 if (s == NULL) 149 fatalx("no memory for string %s.", val); 150 151 if (!parse_semi(cfile)) { 152 free(s); 153 return (NULL); 154 } 155 return (s); 156 } 157 158 /* 159 * hostname :== identifier | hostname DOT identifier 160 */ 161 char * 162 parse_host_name(FILE *cfile) 163 { 164 char *val, *s, *t; 165 int token, len = 0; 166 pair c = NULL; 167 168 /* Read a dotted hostname... */ 169 do { 170 /* Read a token, which should be an identifier. */ 171 token = next_token(&val, cfile); 172 if (!is_identifier(token)) { 173 parse_warn("expecting an identifier in hostname"); 174 skip_to_semi(cfile); 175 return (NULL); 176 } 177 /* Store this identifier... */ 178 s = strdup(val); 179 if (s == NULL) 180 fatalx("can't allocate temp space for hostname."); 181 c = cons((caddr_t) s, c); 182 len += strlen(s) + 1; 183 /* 184 * Look for a dot; if it's there, keep going, otherwise 185 * we're done. 186 */ 187 token = peek_token(&val, cfile); 188 if (token == '.') 189 token = next_token(&val, cfile); 190 } while (token == '.'); 191 192 /* Assemble the hostname together into a string. */ 193 if (!(s = malloc(len))) 194 fatalx("can't allocate space for hostname."); 195 t = s + len; 196 *--t = '\0'; 197 while (c) { 198 pair cdr = c->cdr; 199 int l = strlen((char *)c->car); 200 201 t -= l; 202 memcpy(t, (char *)c->car, l); 203 /* Free up temp space. */ 204 free(c->car); 205 free(c); 206 c = cdr; 207 if (t != s) 208 *--t = '.'; 209 } 210 return (s); 211 } 212 213 /* 214 * hardware-parameter :== HARDWARE ETHERNET csns SEMI 215 * csns :== NUMBER | csns COLON NUMBER 216 */ 217 void 218 parse_hardware_param(FILE *cfile, struct hardware *hardware) 219 { 220 char *val; 221 int token, hlen; 222 unsigned char *t; 223 224 token = next_token(&val, cfile); 225 switch (token) { 226 case TOK_ETHERNET: 227 hardware->htype = HTYPE_ETHER; 228 break; 229 case TOK_IPSEC_TUNNEL: 230 hardware->htype = HTYPE_IPSEC_TUNNEL; 231 break; 232 default: 233 parse_warn("expecting a network hardware type"); 234 skip_to_semi(cfile); 235 return; 236 } 237 238 /* 239 * Parse the hardware address information. Technically, it 240 * would make a lot of sense to restrict the length of the data 241 * we'll accept here to the length of a particular hardware 242 * address type. Unfortunately, there are some broken clients 243 * out there that put bogus data in the chaddr buffer, and we 244 * accept that data in the lease file rather than simply failing 245 * on such clients. Yuck. 246 */ 247 hlen = 0; 248 t = parse_numeric_aggregate(cfile, NULL, &hlen, ':', 16, 8); 249 if (!t) 250 return; 251 if (hlen > sizeof(hardware->haddr)) { 252 free(t); 253 parse_warn("hardware address too long"); 254 } else { 255 hardware->hlen = hlen; 256 memcpy((unsigned char *)&hardware->haddr[0], t, 257 hardware->hlen); 258 if (hlen < sizeof(hardware->haddr)) 259 memset(&hardware->haddr[hlen], 0, 260 sizeof(hardware->haddr) - hlen); 261 free(t); 262 } 263 264 token = next_token(&val, cfile); 265 if (token != ';') { 266 parse_warn("expecting semicolon."); 267 skip_to_semi(cfile); 268 } 269 } 270 271 /* 272 * lease-time :== NUMBER SEMI 273 */ 274 void 275 parse_lease_time(FILE *cfile, time_t *timep) 276 { 277 const char *errstr; 278 char *val; 279 uint32_t value; 280 int token; 281 282 token = next_token(&val, cfile); 283 284 value = strtonum(val, 0, UINT32_MAX, &errstr); 285 if (errstr) { 286 parse_warn("lease time is %s: %s", errstr, val); 287 skip_to_semi(cfile); 288 return; 289 } 290 291 *timep = value; 292 293 parse_semi(cfile); 294 } 295 296 /* 297 * No BNF for numeric aggregates - that's defined by the caller. What 298 * this function does is to parse a sequence of numbers separated by the 299 * token specified in separator. If max is zero, any number of numbers 300 * will be parsed; otherwise, exactly max numbers are expected. Base 301 * and size tell us how to internalize the numbers once they've been 302 * tokenized. 303 */ 304 unsigned char * 305 parse_numeric_aggregate(FILE *cfile, unsigned char *buf, int *max, 306 int separator, int base, int size) 307 { 308 char *val, *t; 309 int token, count = 0; 310 unsigned char *bufp = buf, *s = NULL; 311 pair c = NULL; 312 313 if (!bufp && *max) { 314 bufp = malloc(*max * size / 8); 315 if (!bufp) 316 fatalx("can't allocate space for numeric aggregate"); 317 } else 318 s = bufp; 319 320 do { 321 if (count) { 322 token = peek_token(&val, cfile); 323 if (token != separator) { 324 if (!*max) 325 break; 326 if (token != '{' && token != '}') 327 token = next_token(&val, cfile); 328 parse_warn("too few numbers."); 329 if (token != ';') 330 skip_to_semi(cfile); 331 return (NULL); 332 } 333 token = next_token(&val, cfile); 334 } 335 token = next_token(&val, cfile); 336 337 if (token == EOF) { 338 parse_warn("unexpected end of file"); 339 break; 340 } 341 if (token != TOK_NUMBER && token != TOK_NUMBER_OR_NAME) { 342 parse_warn("expecting numeric value."); 343 skip_to_semi(cfile); 344 return (NULL); 345 } 346 /* 347 * If we can, convert the number now; otherwise, build a 348 * linked list of all the numbers. 349 */ 350 if (s) { 351 convert_num(s, val, base, size); 352 s += size / 8; 353 } else { 354 t = strdup(val); 355 if (t == NULL) 356 fatalx("no temp space for number."); 357 c = cons(t, c); 358 } 359 } while (++count != *max); 360 361 /* If we had to cons up a list, convert it now. */ 362 if (c) { 363 bufp = malloc(count * size / 8); 364 if (!bufp) 365 fatalx("can't allocate space for numeric aggregate."); 366 s = bufp + count - size / 8; 367 *max = count; 368 } 369 while (c) { 370 pair cdr = c->cdr; 371 convert_num(s, (char *)c->car, base, size); 372 s -= size / 8; 373 /* Free up temp space. */ 374 free(c->car); 375 free(c); 376 c = cdr; 377 } 378 return (bufp); 379 } 380 381 void 382 convert_num(unsigned char *buf, char *str, int base, int size) 383 { 384 int negative = 0, tval, max; 385 u_int32_t val = 0; 386 char *ptr = str; 387 388 if (*ptr == '-') { 389 negative = 1; 390 ptr++; 391 } 392 393 /* If base wasn't specified, figure it out from the data. */ 394 if (!base) { 395 if (ptr[0] == '0') { 396 if (ptr[1] == 'x') { 397 base = 16; 398 ptr += 2; 399 } else if (isascii((unsigned char)ptr[1]) && 400 isdigit((unsigned char)ptr[1])) { 401 base = 8; 402 ptr += 1; 403 } else 404 base = 10; 405 } else 406 base = 10; 407 } 408 409 do { 410 tval = *ptr++; 411 /* XXX assumes ASCII... */ 412 if (tval >= 'a') 413 tval = tval - 'a' + 10; 414 else if (tval >= 'A') 415 tval = tval - 'A' + 10; 416 else if (tval >= '0') 417 tval -= '0'; 418 else { 419 log_warnx("Bogus number: %s.", str); 420 break; 421 } 422 if (tval >= base) { 423 log_warnx("Bogus number: %s: digit %d not in base %d", 424 str, tval, base); 425 break; 426 } 427 val = val * base + tval; 428 } while (*ptr); 429 430 if (negative) 431 max = (1 << (size - 1)); 432 else 433 max = (1 << (size - 1)) + ((1 << (size - 1)) - 1); 434 if (val > max) { 435 switch (base) { 436 case 8: 437 log_warnx("value %s%o exceeds max (%d) for precision.", 438 negative ? "-" : "", val, max); 439 break; 440 case 16: 441 log_warnx("value %s%x exceeds max (%d) for precision.", 442 negative ? "-" : "", val, max); 443 break; 444 default: 445 log_warnx("value %s%u exceeds max (%d) for precision.", 446 negative ? "-" : "", val, max); 447 break; 448 } 449 } 450 451 if (negative) { 452 switch (size) { 453 case 8: 454 *buf = -(unsigned long)val; 455 break; 456 case 16: 457 putShort(buf, -(unsigned long)val); 458 break; 459 case 32: 460 putLong(buf, -(unsigned long)val); 461 break; 462 default: 463 log_warnx("Unexpected integer size: %d", size); 464 break; 465 } 466 } else { 467 switch (size) { 468 case 8: 469 *buf = (u_int8_t)val; 470 break; 471 case 16: 472 putUShort(buf, (u_int16_t)val); 473 break; 474 case 32: 475 putULong(buf, val); 476 break; 477 default: 478 log_warnx("Unexpected integer size: %d", size); 479 break; 480 } 481 } 482 } 483 484 /* 485 * date :== NUMBER NUMBER SLASH NUMBER SLASH NUMBER 486 * NUMBER COLON NUMBER COLON NUMBER UTC SEMI 487 * 488 * Dates are always in UTC; first number is day of week; next is 489 * year/month/day; next is hours:minutes:seconds on a 24-hour 490 * clock. 491 */ 492 time_t 493 parse_date(FILE *cfile) 494 { 495 struct tm tm; 496 char timestr[26]; /* "w yyyy/mm/dd hh:mm:ss UTC" */ 497 char *val, *p; 498 size_t n; 499 time_t guess; 500 int token; 501 502 memset(timestr, 0, sizeof(timestr)); 503 504 do { 505 token = peek_token(NULL, cfile); 506 switch (token) { 507 case TOK_NAME: 508 case TOK_NUMBER: 509 case TOK_NUMBER_OR_NAME: 510 case '/': 511 case ':': 512 token = next_token(&val, cfile); 513 n = strlcat(timestr, val, sizeof(timestr)); 514 if (n >= sizeof(timestr)) { 515 /* XXX Will break after year 9999! */ 516 parse_warn("time string too long"); 517 skip_to_semi(cfile); 518 return (0); 519 } 520 break; 521 case';': 522 break; 523 default: 524 parse_warn("invalid time string"); 525 skip_to_semi(cfile); 526 return (0); 527 } 528 } while (token != ';'); 529 530 parse_semi(cfile); 531 532 memset(&tm, 0, sizeof(tm)); /* 'cuz strptime ignores tm_isdt. */ 533 p = strptime(timestr, DB_TIMEFMT, &tm); 534 if (p == NULL || *p != '\0') { 535 p = strptime(timestr, OLD_DB_TIMEFMT, &tm); 536 if (p == NULL || *p != '\0') { 537 parse_warn("unparseable time string"); 538 return (0); 539 } 540 } 541 542 guess = timegm(&tm); 543 if (guess == -1) { 544 parse_warn("time could not be represented"); 545 return (0); 546 } 547 548 return (guess); 549 } 550 551 int warnings_occurred; 552 553 int 554 parse_warn(char *fmt, ...) 555 { 556 static char fbuf[1024]; 557 static char mbuf[1024]; 558 static char spaces[81]; 559 va_list list; 560 int i; 561 562 snprintf(fbuf, sizeof(fbuf), "%s line %d: %s", tlname, lexline, mbuf); 563 va_start(list, fmt); 564 vsnprintf(mbuf, sizeof(mbuf), fbuf, list); 565 va_end(list); 566 567 log_warnx("%s", mbuf); 568 log_warnx("%s", token_line); 569 if (lexchar < sizeof(spaces)) { 570 memset(spaces, 0, sizeof(spaces)); 571 for (i = 0; i < lexchar - 1; i++) { 572 if (token_line[i] == '\t') 573 spaces[i] = '\t'; 574 else 575 spaces[i] = ' '; 576 } 577 } 578 log_warnx("%s^", spaces); 579 580 warnings_occurred = 1; 581 582 return (0); 583 } 584