1 /*- 2 * Copyright (c) 2008 Sean C. Farley <scf@FreeBSD.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer, 10 * without modification, immediately at the beginning of the file. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27 #include <sys/cdefs.h> 28 __FBSDID("$FreeBSD$"); 29 30 #include <sys/param.h> 31 #include <sys/errno.h> 32 #include <sys/stat.h> 33 34 #include <ctype.h> 35 #include <err.h> 36 #include <fcntl.h> 37 #include <grp.h> 38 #include <inttypes.h> 39 #include <libutil.h> 40 #include <paths.h> 41 #include <stdbool.h> 42 #include <stdio.h> 43 #include <stdlib.h> 44 #include <string.h> 45 #include <unistd.h> 46 47 static int lockfd = -1; 48 static char group_dir[PATH_MAX]; 49 static char group_file[PATH_MAX]; 50 static char tempname[PATH_MAX]; 51 static int initialized; 52 53 /* 54 * Initialize statics 55 */ 56 int 57 gr_init(const char *dir, const char *group) 58 { 59 60 if (dir == NULL) { 61 strcpy(group_dir, _PATH_ETC); 62 } else { 63 if (strlen(dir) >= sizeof(group_dir)) { 64 errno = ENAMETOOLONG; 65 return (-1); 66 } 67 strcpy(group_dir, dir); 68 } 69 70 if (group == NULL) { 71 if (dir == NULL) { 72 strcpy(group_file, _PATH_GROUP); 73 } else if (snprintf(group_file, sizeof(group_file), "%s/group", 74 group_dir) > (int)sizeof(group_file)) { 75 errno = ENAMETOOLONG; 76 return (-1); 77 } 78 } else { 79 if (strlen(group) >= sizeof(group_file)) { 80 errno = ENAMETOOLONG; 81 return (-1); 82 } 83 strcpy(group_file, group); 84 } 85 86 initialized = 1; 87 return (0); 88 } 89 90 /* 91 * Lock the group file 92 */ 93 int 94 gr_lock(void) 95 { 96 if (*group_file == '\0') 97 return (-1); 98 99 for (;;) { 100 struct stat st; 101 102 lockfd = flopen(group_file, O_RDONLY|O_NONBLOCK|O_CLOEXEC, 0); 103 if (lockfd == -1) { 104 if (errno == EWOULDBLOCK) { 105 errx(1, "the group file is busy"); 106 } else { 107 err(1, "could not lock the group file: "); 108 } 109 } 110 if (fstat(lockfd, &st) == -1) 111 err(1, "fstat() failed: "); 112 if (st.st_nlink != 0) 113 break; 114 close(lockfd); 115 lockfd = -1; 116 } 117 return (lockfd); 118 } 119 120 /* 121 * Create and open a presmuably safe temp file for editing group data 122 */ 123 int 124 gr_tmp(int mfd) 125 { 126 char buf[8192]; 127 ssize_t nr; 128 const char *p; 129 int tfd; 130 131 if (*group_file == '\0') 132 return (-1); 133 if ((p = strrchr(group_file, '/'))) 134 ++p; 135 else 136 p = group_file; 137 if (snprintf(tempname, sizeof(tempname), "%.*sgroup.XXXXXX", 138 (int)(p - group_file), group_file) >= (int)sizeof(tempname)) { 139 errno = ENAMETOOLONG; 140 return (-1); 141 } 142 if ((tfd = mkstemp(tempname)) == -1) 143 return (-1); 144 if (mfd != -1) { 145 while ((nr = read(mfd, buf, sizeof(buf))) > 0) 146 if (write(tfd, buf, (size_t)nr) != nr) 147 break; 148 if (nr != 0) { 149 unlink(tempname); 150 *tempname = '\0'; 151 close(tfd); 152 return (-1); 153 } 154 } 155 return (tfd); 156 } 157 158 /* 159 * Copy the group file from one descriptor to another, replacing, deleting 160 * or adding a single record on the way. 161 */ 162 int 163 gr_copy(int ffd, int tfd, const struct group *gr, struct group *old_gr) 164 { 165 char buf[8192], *end, *line, *p, *q, *r, t; 166 struct group *fgr; 167 const struct group *sgr; 168 size_t len; 169 int eof, readlen; 170 171 sgr = gr; 172 if (gr == NULL) { 173 line = NULL; 174 if (old_gr == NULL) 175 return (-1); 176 sgr = old_gr; 177 } else if ((line = gr_make(gr)) == NULL) 178 return (-1); 179 180 eof = 0; 181 len = 0; 182 p = q = end = buf; 183 for (;;) { 184 /* find the end of the current line */ 185 for (p = q; q < end && *q != '\0'; ++q) 186 if (*q == '\n') 187 break; 188 189 /* if we don't have a complete line, fill up the buffer */ 190 if (q >= end) { 191 if (eof) 192 break; 193 if ((size_t)(q - p) >= sizeof(buf)) { 194 warnx("group line too long"); 195 errno = EINVAL; /* hack */ 196 goto err; 197 } 198 if (p < end) { 199 q = memmove(buf, p, end -p); 200 end -= p - buf; 201 } else { 202 p = q = end = buf; 203 } 204 readlen = read(ffd, end, sizeof(buf) - (end -buf)); 205 if (readlen == -1) 206 goto err; 207 else 208 len = (size_t)readlen; 209 if (len == 0 && p == buf) 210 break; 211 end += len; 212 len = end - buf; 213 if (len < (ssize_t)sizeof(buf)) { 214 eof = 1; 215 if (len > 0 && buf[len -1] != '\n') 216 ++len, *end++ = '\n'; 217 } 218 continue; 219 } 220 221 /* is it a blank line or a comment? */ 222 for (r = p; r < q && isspace(*r); ++r) 223 /* nothing */; 224 if (r == q || *r == '#') { 225 /* yep */ 226 if (write(tfd, p, q -p + 1) != q - p + 1) 227 goto err; 228 ++q; 229 continue; 230 } 231 232 /* is it the one we're looking for? */ 233 234 t = *q; 235 *q = '\0'; 236 237 fgr = gr_scan(r); 238 239 /* fgr is either a struct group for the current line, 240 * or NULL if the line is malformed. 241 */ 242 243 *q = t; 244 if (fgr == NULL || fgr->gr_gid != sgr->gr_gid) { 245 /* nope */ 246 if (fgr != NULL) 247 free(fgr); 248 if (write(tfd, p, q - p + 1) != q - p + 1) 249 goto err; 250 ++q; 251 continue; 252 } 253 if (old_gr && !gr_equal(fgr, old_gr)) { 254 warnx("entry inconsistent"); 255 free(fgr); 256 errno = EINVAL; /* hack */ 257 goto err; 258 } 259 free(fgr); 260 261 /* it is, replace or remove it */ 262 if (line != NULL) { 263 len = strlen(line); 264 if (write(tfd, line, len) != (int) len) 265 goto err; 266 } else { 267 /* when removed, avoid the \n */ 268 q++; 269 } 270 /* we're done, just copy the rest over */ 271 for (;;) { 272 if (write(tfd, q, end - q) != end - q) 273 goto err; 274 q = buf; 275 readlen = read(ffd, buf, sizeof(buf)); 276 if (readlen == 0) 277 break; 278 else 279 len = (size_t)readlen; 280 if (readlen == -1) 281 goto err; 282 end = buf + len; 283 } 284 goto done; 285 } 286 287 /* if we got here, we didn't find the old entry */ 288 if (line == NULL) { 289 errno = ENOENT; 290 goto err; 291 } 292 len = strlen(line); 293 if ((size_t)write(tfd, line, len) != len || 294 write(tfd, "\n", 1) != 1) 295 goto err; 296 done: 297 if (line != NULL) 298 free(line); 299 return (0); 300 err: 301 if (line != NULL) 302 free(line); 303 return (-1); 304 } 305 306 /* 307 * Regenerate the group file 308 */ 309 int 310 gr_mkdb(void) 311 { 312 if (chmod(tempname, 0644) != 0) 313 return (-1); 314 315 return (rename(tempname, group_file)); 316 } 317 318 /* 319 * Clean up. Preserves errno for the caller's convenience. 320 */ 321 void 322 gr_fini(void) 323 { 324 int serrno; 325 326 if (!initialized) 327 return; 328 initialized = 0; 329 serrno = errno; 330 if (*tempname != '\0') { 331 unlink(tempname); 332 *tempname = '\0'; 333 } 334 if (lockfd != -1) 335 close(lockfd); 336 errno = serrno; 337 } 338 339 /* 340 * Compares two struct group's. 341 */ 342 int 343 gr_equal(const struct group *gr1, const struct group *gr2) 344 { 345 int gr1_ndx; 346 int gr2_ndx; 347 348 /* Check that the non-member information is the same. */ 349 if (gr1->gr_name == NULL || gr2->gr_name == NULL) { 350 if (gr1->gr_name != gr2->gr_name) 351 return (false); 352 } else if (strcmp(gr1->gr_name, gr2->gr_name) != 0) 353 return (false); 354 if (gr1->gr_passwd == NULL || gr2->gr_passwd == NULL) { 355 if (gr1->gr_passwd != gr2->gr_passwd) 356 return (false); 357 } else if (strcmp(gr1->gr_passwd, gr2->gr_passwd) != 0) 358 return (false); 359 if (gr1->gr_gid != gr2->gr_gid) 360 return (false); 361 362 /* Check all members in both groups. */ 363 if (gr1->gr_mem == NULL || gr2->gr_mem == NULL) { 364 if (gr1->gr_mem != gr2->gr_mem) 365 return (false); 366 } else { 367 for (gr1_ndx = 0; gr1->gr_mem[gr1_ndx] != NULL; gr1_ndx++) { 368 for (gr2_ndx = 0;; gr2_ndx++) { 369 if (gr2->gr_mem[gr2_ndx] == NULL) 370 return (false); 371 if (strcmp(gr1->gr_mem[gr1_ndx], 372 gr2->gr_mem[gr2_ndx]) == 0) { 373 break; 374 } 375 } 376 } 377 378 /* Check that group2 does not have more members than group1. */ 379 if (gr2->gr_mem[gr1_ndx] != NULL) 380 return (false); 381 } 382 383 return (true); 384 } 385 386 /* 387 * Make a group line out of a struct group. 388 */ 389 char * 390 gr_make(const struct group *gr) 391 { 392 const char *group_line_format = "%s:%s:%ju:"; 393 const char *sep; 394 char *line; 395 char *p; 396 size_t line_size; 397 int ndx; 398 399 /* Calculate the length of the group line. */ 400 line_size = snprintf(NULL, 0, group_line_format, gr->gr_name, 401 gr->gr_passwd, (uintmax_t)gr->gr_gid) + 1; 402 if (gr->gr_mem != NULL) { 403 for (ndx = 0; gr->gr_mem[ndx] != NULL; ndx++) 404 line_size += strlen(gr->gr_mem[ndx]) + 1; 405 if (ndx > 0) 406 line_size--; 407 } 408 409 /* Create the group line and fill it. */ 410 if ((line = p = malloc(line_size)) == NULL) 411 return (NULL); 412 p += sprintf(p, group_line_format, gr->gr_name, gr->gr_passwd, 413 (uintmax_t)gr->gr_gid); 414 if (gr->gr_mem != NULL) { 415 sep = ""; 416 for (ndx = 0; gr->gr_mem[ndx] != NULL; ndx++) { 417 p = stpcpy(p, sep); 418 p = stpcpy(p, gr->gr_mem[ndx]); 419 sep = ","; 420 } 421 } 422 423 return (line); 424 } 425 426 /* 427 * Duplicate a struct group. 428 */ 429 struct group * 430 gr_dup(const struct group *gr) 431 { 432 struct group *newgr; 433 char *dst; 434 size_t len; 435 int ndx; 436 int num_mem; 437 438 /* Calculate size of the group. */ 439 len = sizeof(*newgr); 440 if (gr->gr_name != NULL) 441 len += strlen(gr->gr_name) + 1; 442 if (gr->gr_passwd != NULL) 443 len += strlen(gr->gr_passwd) + 1; 444 if (gr->gr_mem != NULL) { 445 for (num_mem = 0; gr->gr_mem[num_mem] != NULL; num_mem++) 446 len += strlen(gr->gr_mem[num_mem]) + 1; 447 len += (num_mem + 1) * sizeof(*gr->gr_mem); 448 } else 449 num_mem = -1; 450 /* Create new group and copy old group into it. */ 451 if ((newgr = malloc(len)) == NULL) 452 return (NULL); 453 /* point new gr_mem to end of struct + 1 */ 454 if (gr->gr_mem != NULL) 455 newgr->gr_mem = (char **)(newgr + 1); 456 else 457 newgr->gr_mem = NULL; 458 /* point dst after the end of all the gr_mem pointers in newgr */ 459 dst = (char *)&newgr->gr_mem[num_mem + 1]; 460 if (gr->gr_name != NULL) { 461 newgr->gr_name = dst; 462 dst = stpcpy(dst, gr->gr_name) + 1; 463 } else { 464 newgr->gr_name = NULL; 465 } 466 if (gr->gr_passwd != NULL) { 467 newgr->gr_passwd = dst; 468 dst = stpcpy(dst, gr->gr_passwd) + 1; 469 } else { 470 newgr->gr_passwd = NULL; 471 } 472 newgr->gr_gid = gr->gr_gid; 473 if (gr->gr_mem != NULL) { 474 for (ndx = 0; ndx < num_mem; ndx++) { 475 newgr->gr_mem[ndx] = dst; 476 dst = stpcpy(dst, gr->gr_mem[ndx]) + 1; 477 } 478 newgr->gr_mem[ndx] = NULL; 479 } 480 return (newgr); 481 } 482 483 /* 484 * Add a new member name to a struct group. 485 */ 486 struct group * 487 gr_add(struct group *gr, char *newmember) 488 { 489 size_t mlen; 490 int num_mem=0; 491 char **members; 492 struct group *newgr; 493 494 if (newmember == NULL) 495 return(gr_dup(gr)); 496 497 if (gr->gr_mem != NULL) { 498 for (num_mem = 0; gr->gr_mem[num_mem] != NULL; num_mem++) { 499 if (strcmp(gr->gr_mem[num_mem], newmember) == 0) { 500 errno = EEXIST; 501 return (NULL); 502 } 503 } 504 } 505 /* Allocate enough for current pointers + 1 more and NULL marker */ 506 mlen = (num_mem + 2) * sizeof(*gr->gr_mem); 507 if ((members = malloc(mlen)) == NULL) 508 return (NULL); 509 memcpy(members, gr->gr_mem, num_mem * sizeof(*gr->gr_mem)); 510 members[num_mem++] = newmember; 511 members[num_mem] = NULL; 512 gr->gr_mem = members; 513 newgr = gr_dup(gr); 514 free(members); 515 return (newgr); 516 } 517 518 /* 519 * Scan a line and place it into a group structure. 520 */ 521 static bool 522 __gr_scan(char *line, struct group *gr) 523 { 524 char *loc; 525 int ndx; 526 527 /* Assign non-member information to structure. */ 528 gr->gr_name = line; 529 if ((loc = strchr(line, ':')) == NULL) 530 return (false); 531 *loc = '\0'; 532 gr->gr_passwd = loc + 1; 533 if (*gr->gr_passwd == ':') 534 *gr->gr_passwd = '\0'; 535 else { 536 if ((loc = strchr(loc + 1, ':')) == NULL) 537 return (false); 538 *loc = '\0'; 539 } 540 if (sscanf(loc + 1, "%u", &gr->gr_gid) != 1) 541 return (false); 542 543 /* Assign member information to structure. */ 544 if ((loc = strchr(loc + 1, ':')) == NULL) 545 return (false); 546 line = loc + 1; 547 gr->gr_mem = NULL; 548 ndx = 0; 549 do { 550 gr->gr_mem = reallocf(gr->gr_mem, sizeof(*gr->gr_mem) * 551 (ndx + 1)); 552 if (gr->gr_mem == NULL) 553 return (false); 554 555 /* Skip locations without members (i.e., empty string). */ 556 do { 557 gr->gr_mem[ndx] = strsep(&line, ","); 558 } while (gr->gr_mem[ndx] != NULL && *gr->gr_mem[ndx] == '\0'); 559 } while (gr->gr_mem[ndx++] != NULL); 560 561 return (true); 562 } 563 564 /* 565 * Create a struct group from a line. 566 */ 567 struct group * 568 gr_scan(const char *line) 569 { 570 struct group gr; 571 char *line_copy; 572 struct group *new_gr; 573 574 if ((line_copy = strdup(line)) == NULL) 575 return (NULL); 576 if (!__gr_scan(line_copy, &gr)) { 577 free(line_copy); 578 return (NULL); 579 } 580 new_gr = gr_dup(&gr); 581 free(line_copy); 582 if (gr.gr_mem != NULL) 583 free(gr.gr_mem); 584 585 return (new_gr); 586 } 587