1 /* 2 * Copyright (c) 1992, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Rick Macklem at The University of Guelph. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37 #if defined(LIBC_SCCS) && !defined(lint) 38 static char sccsid[] = "@(#)getnetgrent.c 8.2 (Berkeley) 4/27/95"; 39 #endif /* LIBC_SCCS and not lint */ 40 #include <sys/cdefs.h> 41 __FBSDID("$FreeBSD$"); 42 43 #include <ctype.h> 44 #include <stdio.h> 45 #include <stdlib.h> 46 #include <string.h> 47 #include <unistd.h> 48 49 #ifdef YP 50 /* 51 * Notes: 52 * We want to be able to use NIS netgroups properly while retaining 53 * the ability to use a local /etc/netgroup file. Unfortunately, you 54 * can't really do both at the same time - at least, not efficiently. 55 * NetBSD deals with this problem by creating a netgroup database 56 * using Berkeley DB (just like the password database) that allows 57 * for lookups using netgroup, netgroup.byuser or netgroup.byhost 58 * searches. This is a neat idea, but I don't have time to implement 59 * something like that now. (I think ultimately it would be nice 60 * if we DB-fied the group and netgroup stuff all in one shot, but 61 * for now I'm satisfied just to have something that works well 62 * without requiring massive code changes.) 63 * 64 * Therefore, to still permit the use of the local file and maintain 65 * optimum NIS performance, we allow for the following conditions: 66 * 67 * - If /etc/netgroup does not exist and NIS is turned on, we use 68 * NIS netgroups only. 69 * 70 * - If /etc/netgroup exists but is empty, we use NIS netgroups 71 * only. 72 * 73 * - If /etc/netgroup exists and contains _only_ a '+', we use 74 * NIS netgroups only. 75 * 76 * - If /etc/netgroup exists, contains locally defined netgroups 77 * and a '+', we use a mixture of NIS and the local entries. 78 * This method should return the same NIS data as just using 79 * NIS alone, but it will be slower if the NIS netgroup database 80 * is large (innetgr() in particular will suffer since extra 81 * processing has to be done in order to determine memberships 82 * using just the raw netgroup data). 83 * 84 * - If /etc/netgroup exists and contains only locally defined 85 * netgroup entries, we use just those local entries and ignore 86 * NIS (this is the original, pre-NIS behavior). 87 */ 88 89 #include <rpc/rpc.h> 90 #include <rpcsvc/yp_prot.h> 91 #include <rpcsvc/ypclnt.h> 92 #include <sys/types.h> 93 #include <sys/stat.h> 94 #include <sys/param.h> 95 #include <sys/errno.h> 96 static char *_netgr_yp_domain; 97 int _use_only_yp; 98 static int _netgr_yp_enabled; 99 static int _yp_innetgr; 100 #endif 101 102 #ifndef _PATH_NETGROUP 103 #define _PATH_NETGROUP "/etc/netgroup" 104 #endif 105 106 /* 107 * Static Variables and functions used by setnetgrent(), getnetgrent() and 108 * endnetgrent(). 109 * There are two linked lists: 110 * - linelist is just used by setnetgrent() to parse the net group file via. 111 * parse_netgrp() 112 * - netgrp is the list of entries for the current netgroup 113 */ 114 struct linelist { 115 struct linelist *l_next; /* Chain ptr. */ 116 int l_parsed; /* Flag for cycles */ 117 char *l_groupname; /* Name of netgroup */ 118 char *l_line; /* Netgroup entrie(s) to be parsed */ 119 }; 120 121 struct netgrp { 122 struct netgrp *ng_next; /* Chain ptr */ 123 char *ng_str[3]; /* Field pointers, see below */ 124 }; 125 #define NG_HOST 0 /* Host name */ 126 #define NG_USER 1 /* User name */ 127 #define NG_DOM 2 /* and Domain name */ 128 129 static struct linelist *linehead = (struct linelist *)0; 130 static struct netgrp *nextgrp = (struct netgrp *)0; 131 static struct { 132 struct netgrp *gr; 133 char *grname; 134 } grouphead = { 135 (struct netgrp *)0, 136 (char *)0, 137 }; 138 static FILE *netf = (FILE *)0; 139 140 static int parse_netgrp(const char *); 141 static struct linelist *read_for_group(const char *); 142 void setnetgrent(const char *); 143 void endnetgrent(void); 144 int getnetgrent(char **, char **, char **); 145 int innetgr(const char *, const char *, const char *, const char *); 146 147 #define LINSIZ 1024 /* Length of netgroup file line */ 148 149 /* 150 * setnetgrent() 151 * Parse the netgroup file looking for the netgroup and build the list 152 * of netgrp structures. Let parse_netgrp() and read_for_group() do 153 * most of the work. 154 */ 155 void 156 setnetgrent(const char *group) 157 { 158 #ifdef YP 159 struct stat _yp_statp; 160 char _yp_plus; 161 #endif 162 163 /* Sanity check */ 164 165 if (group == NULL || !strlen(group)) 166 return; 167 168 if (grouphead.gr == (struct netgrp *)0 || 169 strcmp(group, grouphead.grname)) { 170 endnetgrent(); 171 #ifdef YP 172 /* Presumed guilty until proven innocent. */ 173 _use_only_yp = 0; 174 /* 175 * If /etc/netgroup doesn't exist or is empty, 176 * use NIS exclusively. 177 */ 178 if (((stat(_PATH_NETGROUP, &_yp_statp) < 0) && 179 errno == ENOENT) || _yp_statp.st_size == 0) 180 _use_only_yp = _netgr_yp_enabled = 1; 181 if ((netf = fopen(_PATH_NETGROUP,"r")) != NULL ||_use_only_yp){ 182 /* 183 * Icky: grab the first character of the netgroup file 184 * and turn on NIS if it's a '+'. rewind the stream 185 * afterwards so we don't goof up read_for_group() later. 186 */ 187 if (netf) { 188 fscanf(netf, "%c", &_yp_plus); 189 rewind(netf); 190 if (_yp_plus == '+') 191 _use_only_yp = _netgr_yp_enabled = 1; 192 } 193 /* 194 * If we were called specifically for an innetgr() 195 * lookup and we're in NIS-only mode, short-circuit 196 * parse_netgroup() and cut directly to the chase. 197 */ 198 if (_use_only_yp && _yp_innetgr) { 199 /* dohw! */ 200 if (netf != NULL) 201 fclose(netf); 202 return; 203 } 204 #else 205 if ((netf = fopen(_PATH_NETGROUP, "r"))) { 206 #endif 207 if (parse_netgrp(group)) 208 endnetgrent(); 209 else { 210 grouphead.grname = (char *) 211 malloc(strlen(group) + 1); 212 strcpy(grouphead.grname, group); 213 } 214 if (netf) 215 fclose(netf); 216 } 217 } 218 nextgrp = grouphead.gr; 219 } 220 221 /* 222 * Get the next netgroup off the list. 223 */ 224 int 225 getnetgrent(char **hostp, char **userp, char **domp) 226 { 227 #ifdef YP 228 _yp_innetgr = 0; 229 #endif 230 231 if (nextgrp) { 232 *hostp = nextgrp->ng_str[NG_HOST]; 233 *userp = nextgrp->ng_str[NG_USER]; 234 *domp = nextgrp->ng_str[NG_DOM]; 235 nextgrp = nextgrp->ng_next; 236 return (1); 237 } 238 return (0); 239 } 240 241 /* 242 * endnetgrent() - cleanup 243 */ 244 void 245 endnetgrent(void) 246 { 247 struct linelist *lp, *olp; 248 struct netgrp *gp, *ogp; 249 250 lp = linehead; 251 while (lp) { 252 olp = lp; 253 lp = lp->l_next; 254 free(olp->l_groupname); 255 free(olp->l_line); 256 free((char *)olp); 257 } 258 linehead = (struct linelist *)0; 259 if (grouphead.grname) { 260 free(grouphead.grname); 261 grouphead.grname = (char *)0; 262 } 263 gp = grouphead.gr; 264 while (gp) { 265 ogp = gp; 266 gp = gp->ng_next; 267 if (ogp->ng_str[NG_HOST]) 268 free(ogp->ng_str[NG_HOST]); 269 if (ogp->ng_str[NG_USER]) 270 free(ogp->ng_str[NG_USER]); 271 if (ogp->ng_str[NG_DOM]) 272 free(ogp->ng_str[NG_DOM]); 273 free((char *)ogp); 274 } 275 grouphead.gr = (struct netgrp *)0; 276 nextgrp = (struct netgrp *)0; 277 #ifdef YP 278 _netgr_yp_enabled = 0; 279 #endif 280 } 281 282 #ifdef YP 283 static int 284 _listmatch(const char *list, const char *group, int len) 285 { 286 const char *ptr = list; 287 const char *cptr; 288 int glen = strlen(group); 289 290 /* skip possible leading whitespace */ 291 while(isspace((unsigned char)*ptr)) 292 ptr++; 293 294 while (ptr < list + len) { 295 cptr = ptr; 296 while(*ptr != ',' && *ptr != '\0' && !isspace((unsigned char)*ptr)) 297 ptr++; 298 if (strncmp(cptr, group, glen) == 0 && glen == (ptr - cptr)) 299 return(1); 300 while(*ptr == ',' || isspace((unsigned char)*ptr)) 301 ptr++; 302 } 303 304 return(0); 305 } 306 307 static int 308 _buildkey(char *key, const char *str, const char *dom, int *rotation) 309 { 310 (*rotation)++; 311 if (*rotation > 4) 312 return(0); 313 switch(*rotation) { 314 case(1): sprintf((char *)key, "%s.%s", str, dom ? dom : "*"); 315 break; 316 case(2): sprintf((char *)key, "%s.*", str); 317 break; 318 case(3): sprintf((char *)key, "*.%s", dom ? dom : "*"); 319 break; 320 case(4): sprintf((char *)key, "*.*"); 321 break; 322 } 323 return(1); 324 } 325 #endif 326 327 /* 328 * Search for a match in a netgroup. 329 */ 330 int 331 innetgr(const char *group, const char *host, const char *user, const char *dom) 332 { 333 char *hst, *usr, *dm; 334 #ifdef YP 335 char *result; 336 int resultlen; 337 int rv; 338 #endif 339 /* Sanity check */ 340 341 if (group == NULL || !strlen(group)) 342 return (0); 343 344 #ifdef YP 345 _yp_innetgr = 1; 346 #endif 347 setnetgrent(group); 348 #ifdef YP 349 _yp_innetgr = 0; 350 /* 351 * If we're in NIS-only mode, do the search using 352 * NIS 'reverse netgroup' lookups. 353 */ 354 if (_use_only_yp) { 355 char _key[MAXHOSTNAMELEN]; 356 int rot = 0, y = 0; 357 358 if(yp_get_default_domain(&_netgr_yp_domain)) 359 return(0); 360 while(_buildkey(_key, user ? user : host, dom, &rot)) { 361 y = yp_match(_netgr_yp_domain, user? "netgroup.byuser": 362 "netgroup.byhost", _key, strlen(_key), &result, 363 &resultlen); 364 if (y) { 365 /* 366 * If we get an error other than 'no 367 * such key in map' then something is 368 * wrong and we should stop the search. 369 */ 370 if (y != YPERR_KEY) 371 break; 372 } else { 373 rv = _listmatch(result, group, resultlen); 374 free(result); 375 if (rv) 376 return(1); 377 else 378 return(0); 379 } 380 } 381 /* 382 * Couldn't match using NIS-exclusive mode. If the error 383 * was YPERR_MAP, then the failure happened because there 384 * was no netgroup.byhost or netgroup.byuser map. The odds 385 * are we are talking to a Sun NIS+ server in YP emulation 386 * mode; if this is the case, then we have to do the check 387 * the 'old-fashioned' way by grovelling through the netgroup 388 * map and resolving memberships on the fly. 389 */ 390 if (y != YPERR_MAP) 391 return(0); 392 } 393 394 setnetgrent(group); 395 #endif /* YP */ 396 397 while (getnetgrent(&hst, &usr, &dm)) 398 if ((host == NULL || hst == NULL || !strcmp(host, hst)) && 399 (user == NULL || usr == NULL || !strcmp(user, usr)) && 400 ( dom == NULL || dm == NULL || !strcmp(dom, dm))) { 401 endnetgrent(); 402 return (1); 403 } 404 endnetgrent(); 405 return (0); 406 } 407 408 /* 409 * Parse the netgroup file setting up the linked lists. 410 */ 411 static int 412 parse_netgrp(const char *group) 413 { 414 char *spos, *epos; 415 int len, strpos; 416 #ifdef DEBUG 417 int fields; 418 #endif 419 char *pos, *gpos; 420 struct netgrp *grp; 421 struct linelist *lp = linehead; 422 423 /* 424 * First, see if the line has already been read in. 425 */ 426 while (lp) { 427 if (!strcmp(group, lp->l_groupname)) 428 break; 429 lp = lp->l_next; 430 } 431 if (lp == (struct linelist *)0 && 432 (lp = read_for_group(group)) == (struct linelist *)0) 433 return (1); 434 if (lp->l_parsed) { 435 #ifdef DEBUG 436 /* 437 * This error message is largely superflous since the 438 * code handles the error condition sucessfully, and 439 * spewing it out from inside libc can actually hose 440 * certain programs. 441 */ 442 fprintf(stderr, "Cycle in netgroup %s\n", lp->l_groupname); 443 #endif 444 return (1); 445 } else 446 lp->l_parsed = 1; 447 pos = lp->l_line; 448 /* Watch for null pointer dereferences, dammit! */ 449 while (pos != NULL && *pos != '\0') { 450 if (*pos == '(') { 451 grp = (struct netgrp *)malloc(sizeof (struct netgrp)); 452 bzero((char *)grp, sizeof (struct netgrp)); 453 grp->ng_next = grouphead.gr; 454 grouphead.gr = grp; 455 pos++; 456 gpos = strsep(&pos, ")"); 457 #ifdef DEBUG 458 fields = 0; 459 #endif 460 for (strpos = 0; strpos < 3; strpos++) { 461 if ((spos = strsep(&gpos, ","))) { 462 #ifdef DEBUG 463 fields++; 464 #endif 465 while (*spos == ' ' || *spos == '\t') 466 spos++; 467 if ((epos = strpbrk(spos, " \t"))) { 468 *epos = '\0'; 469 len = epos - spos; 470 } else 471 len = strlen(spos); 472 if (len > 0) { 473 grp->ng_str[strpos] = (char *) 474 malloc(len + 1); 475 bcopy(spos, grp->ng_str[strpos], 476 len + 1); 477 } 478 } else { 479 /* 480 * All other systems I've tested 481 * return NULL for empty netgroup 482 * fields. It's up to user programs 483 * to handle the NULLs appropriately. 484 */ 485 grp->ng_str[strpos] = NULL; 486 } 487 } 488 #ifdef DEBUG 489 /* 490 * Note: on other platforms, malformed netgroup 491 * entries are not normally flagged. While we 492 * can catch bad entries and report them, we should 493 * stay silent by default for compatibility's sake. 494 */ 495 if (fields < 3) 496 fprintf(stderr, "Bad entry (%s%s%s%s%s) in netgroup \"%s\"\n", 497 grp->ng_str[NG_HOST] == NULL ? "" : grp->ng_str[NG_HOST], 498 grp->ng_str[NG_USER] == NULL ? "" : ",", 499 grp->ng_str[NG_USER] == NULL ? "" : grp->ng_str[NG_USER], 500 grp->ng_str[NG_DOM] == NULL ? "" : ",", 501 grp->ng_str[NG_DOM] == NULL ? "" : grp->ng_str[NG_DOM], 502 lp->l_groupname); 503 #endif 504 } else { 505 spos = strsep(&pos, ", \t"); 506 if (parse_netgrp(spos)) 507 continue; 508 } 509 if (pos == NULL) 510 break; 511 while (*pos == ' ' || *pos == ',' || *pos == '\t') 512 pos++; 513 } 514 return (0); 515 } 516 517 /* 518 * Read the netgroup file and save lines until the line for the netgroup 519 * is found. Return 1 if eof is encountered. 520 */ 521 static struct linelist * 522 read_for_group(const char *group) 523 { 524 char *pos, *spos, *linep, *olinep; 525 int len, olen; 526 int cont; 527 struct linelist *lp; 528 char line[LINSIZ + 2]; 529 #ifdef YP 530 char *result; 531 int resultlen; 532 533 while (_netgr_yp_enabled || fgets(line, LINSIZ, netf) != NULL) { 534 if (_netgr_yp_enabled) { 535 if(!_netgr_yp_domain) 536 if(yp_get_default_domain(&_netgr_yp_domain)) 537 continue; 538 if (yp_match(_netgr_yp_domain, "netgroup", group, 539 strlen(group), &result, &resultlen)) { 540 free(result); 541 if (_use_only_yp) 542 return ((struct linelist *)0); 543 else { 544 _netgr_yp_enabled = 0; 545 continue; 546 } 547 } 548 snprintf(line, LINSIZ, "%s %s", group, result); 549 free(result); 550 } 551 #else 552 while (fgets(line, LINSIZ, netf) != NULL) { 553 #endif 554 pos = (char *)&line; 555 #ifdef YP 556 if (*pos == '+') { 557 _netgr_yp_enabled = 1; 558 continue; 559 } 560 #endif 561 if (*pos == '#') 562 continue; 563 while (*pos == ' ' || *pos == '\t') 564 pos++; 565 spos = pos; 566 while (*pos != ' ' && *pos != '\t' && *pos != '\n' && 567 *pos != '\0') 568 pos++; 569 len = pos - spos; 570 while (*pos == ' ' || *pos == '\t') 571 pos++; 572 if (*pos != '\n' && *pos != '\0') { 573 lp = (struct linelist *)malloc(sizeof (*lp)); 574 lp->l_parsed = 0; 575 lp->l_groupname = (char *)malloc(len + 1); 576 bcopy(spos, lp->l_groupname, len); 577 *(lp->l_groupname + len) = '\0'; 578 len = strlen(pos); 579 olen = 0; 580 581 /* 582 * Loop around handling line continuations. 583 */ 584 do { 585 if (*(pos + len - 1) == '\n') 586 len--; 587 if (*(pos + len - 1) == '\\') { 588 len--; 589 cont = 1; 590 } else 591 cont = 0; 592 if (len > 0) { 593 linep = (char *)malloc(olen + len + 1); 594 if (olen > 0) { 595 bcopy(olinep, linep, olen); 596 free(olinep); 597 } 598 bcopy(pos, linep + olen, len); 599 olen += len; 600 *(linep + olen) = '\0'; 601 olinep = linep; 602 } 603 if (cont) { 604 if (fgets(line, LINSIZ, netf)) { 605 pos = line; 606 len = strlen(pos); 607 } else 608 cont = 0; 609 } 610 } while (cont); 611 lp->l_line = linep; 612 lp->l_next = linehead; 613 linehead = lp; 614 615 /* 616 * If this is the one we wanted, we are done. 617 */ 618 if (!strcmp(lp->l_groupname, group)) 619 return (lp); 620 } 621 } 622 #ifdef YP 623 /* 624 * Yucky. The recursive nature of this whole mess might require 625 * us to make more than one pass through the netgroup file. 626 * This might be best left outside the #ifdef YP, but YP is 627 * defined by default anyway, so I'll leave it like this 628 * until I know better. 629 */ 630 rewind(netf); 631 #endif 632 return ((struct linelist *)0); 633 } 634