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 struct group_storage { 48 struct group gr; 49 char *members[]; 50 }; 51 52 static int lockfd = -1; 53 static char group_dir[PATH_MAX]; 54 static char group_file[PATH_MAX]; 55 static char tempname[PATH_MAX]; 56 static int initialized; 57 58 static const char group_line_format[] = "%s:%s:%ju:"; 59 60 /* 61 * Initialize statics 62 */ 63 int 64 gr_init(const char *dir, const char *group) 65 { 66 67 if (dir == NULL) { 68 strcpy(group_dir, _PATH_ETC); 69 } else { 70 if (strlen(dir) >= sizeof(group_dir)) { 71 errno = ENAMETOOLONG; 72 return (-1); 73 } 74 strcpy(group_dir, dir); 75 } 76 77 if (group == NULL) { 78 if (dir == NULL) { 79 strcpy(group_file, _PATH_GROUP); 80 } else if (snprintf(group_file, sizeof(group_file), "%s/group", 81 group_dir) > (int)sizeof(group_file)) { 82 errno = ENAMETOOLONG; 83 return (-1); 84 } 85 } else { 86 if (strlen(group) >= sizeof(group_file)) { 87 errno = ENAMETOOLONG; 88 return (-1); 89 } 90 strcpy(group_file, group); 91 } 92 93 initialized = 1; 94 return (0); 95 } 96 97 /* 98 * Lock the group file 99 */ 100 int 101 gr_lock(void) 102 { 103 if (*group_file == '\0') 104 return (-1); 105 106 for (;;) { 107 struct stat st; 108 109 lockfd = open(group_file, O_RDONLY, 0); 110 if (lockfd < 0 || fcntl(lockfd, F_SETFD, 1) == -1) 111 err(1, "%s", group_file); 112 if (flock(lockfd, LOCK_EX|LOCK_NB) == -1) { 113 if (errno == EWOULDBLOCK) { 114 errx(1, "the group file is busy"); 115 } else { 116 err(1, "could not lock the group file: "); 117 } 118 } 119 if (fstat(lockfd, &st) == -1) 120 err(1, "fstat() failed: "); 121 if (st.st_nlink != 0) 122 break; 123 close(lockfd); 124 lockfd = -1; 125 } 126 return (lockfd); 127 } 128 129 /* 130 * Create and open a presmuably safe temp file for editing group data 131 */ 132 int 133 gr_tmp(int mfd) 134 { 135 char buf[8192]; 136 ssize_t nr; 137 const char *p; 138 int tfd; 139 140 if (*group_file == '\0') 141 return (-1); 142 if ((p = strrchr(group_file, '/'))) 143 ++p; 144 else 145 p = group_file; 146 if (snprintf(tempname, sizeof(tempname), "%.*sgroup.XXXXXX", 147 (int)(p - group_file), group_file) >= (int)sizeof(tempname)) { 148 errno = ENAMETOOLONG; 149 return (-1); 150 } 151 if ((tfd = mkstemp(tempname)) == -1) 152 return (-1); 153 if (mfd != -1) { 154 while ((nr = read(mfd, buf, sizeof(buf))) > 0) 155 if (write(tfd, buf, (size_t)nr) != nr) 156 break; 157 if (nr != 0) { 158 unlink(tempname); 159 *tempname = '\0'; 160 close(tfd); 161 return (-1); 162 } 163 } 164 return (tfd); 165 } 166 167 /* 168 * Copy the group file from one descriptor to another, replacing, deleting 169 * or adding a single record on the way. 170 */ 171 int 172 gr_copy(int ffd, int tfd, const struct group *gr, struct group *old_gr) 173 { 174 char buf[8192], *end, *line, *p, *q, *r, t; 175 struct group *fgr; 176 const struct group *sgr; 177 size_t len; 178 int eof, readlen; 179 180 sgr = gr; 181 if (gr == NULL) { 182 line = NULL; 183 if (old_gr == NULL) 184 return (-1); 185 sgr = old_gr; 186 } else if ((line = gr_make(gr)) == NULL) 187 return (-1); 188 189 eof = 0; 190 len = 0; 191 p = q = end = buf; 192 for (;;) { 193 /* find the end of the current line */ 194 for (p = q; q < end && *q != '\0'; ++q) 195 if (*q == '\n') 196 break; 197 198 /* if we don't have a complete line, fill up the buffer */ 199 if (q >= end) { 200 if (eof) 201 break; 202 if ((size_t)(q - p) >= sizeof(buf)) { 203 warnx("group line too long"); 204 errno = EINVAL; /* hack */ 205 goto err; 206 } 207 if (p < end) { 208 q = memmove(buf, p, end -p); 209 end -= p - buf; 210 } else { 211 p = q = end = buf; 212 } 213 readlen = read(ffd, end, sizeof(buf) - (end -buf)); 214 if (readlen == -1) 215 goto err; 216 else 217 len = (size_t)readlen; 218 if (len == 0 && p == buf) 219 break; 220 end += len; 221 len = end - buf; 222 if (len < (ssize_t)sizeof(buf)) { 223 eof = 1; 224 if (len > 0 && buf[len -1] != '\n') 225 ++len, *end++ = '\n'; 226 } 227 continue; 228 } 229 230 /* is it a blank line or a comment? */ 231 for (r = p; r < q && isspace(*r); ++r) 232 /* nothing */; 233 if (r == q || *r == '#') { 234 /* yep */ 235 if (write(tfd, p, q -p + 1) != q - p + 1) 236 goto err; 237 ++q; 238 continue; 239 } 240 241 /* is it the one we're looking for? */ 242 243 t = *q; 244 *q = '\0'; 245 246 fgr = gr_scan(r); 247 248 /* fgr is either a struct group for the current line, 249 * or NULL if the line is malformed. 250 */ 251 252 *q = t; 253 if (fgr == NULL || fgr->gr_gid != sgr->gr_gid) { 254 /* nope */ 255 if (fgr != NULL) 256 free(fgr); 257 if (write(tfd, p, q - p + 1) != q - p + 1) 258 goto err; 259 ++q; 260 continue; 261 } 262 if (old_gr && !gr_equal(fgr, old_gr)) { 263 warnx("entry inconsistent"); 264 free(fgr); 265 errno = EINVAL; /* hack */ 266 goto err; 267 } 268 free(fgr); 269 270 /* it is, replace or remove it */ 271 if (line != NULL) { 272 len = strlen(line); 273 if (write(tfd, line, len) != (int) len) 274 goto err; 275 } else { 276 /* when removed, avoid the \n */ 277 q++; 278 } 279 /* we're done, just copy the rest over */ 280 for (;;) { 281 if (write(tfd, q, end - q) != end - q) 282 goto err; 283 q = buf; 284 readlen = read(ffd, buf, sizeof(buf)); 285 if (readlen == 0) 286 break; 287 else 288 len = (size_t)readlen; 289 if (readlen == -1) 290 goto err; 291 end = buf + len; 292 } 293 goto done; 294 } 295 296 /* if we got here, we didn't find the old entry */ 297 if (line == NULL) { 298 errno = ENOENT; 299 goto err; 300 } 301 len = strlen(line); 302 if ((size_t)write(tfd, line, len) != len || 303 write(tfd, "\n", 1) != 1) 304 goto err; 305 done: 306 if (line != NULL) 307 free(line); 308 return (0); 309 err: 310 if (line != NULL) 311 free(line); 312 return (-1); 313 } 314 315 /* 316 * Regenerate the group file 317 */ 318 int 319 gr_mkdb(void) 320 { 321 if (chmod(tempname, 0644) != 0) 322 return (-1); 323 324 return (rename(tempname, group_file)); 325 } 326 327 /* 328 * Clean up. Preserver errno for the caller's convenience. 329 */ 330 void 331 gr_fini(void) 332 { 333 int serrno; 334 335 if (!initialized) 336 return; 337 initialized = 0; 338 serrno = errno; 339 if (*tempname != '\0') { 340 unlink(tempname); 341 *tempname = '\0'; 342 } 343 if (lockfd != -1) 344 close(lockfd); 345 errno = serrno; 346 } 347 348 /* 349 * Compares two struct group's. 350 */ 351 int 352 gr_equal(const struct group *gr1, const struct group *gr2) 353 { 354 int gr1_ndx; 355 int gr2_ndx; 356 bool found; 357 358 /* Check that the non-member information is the same. */ 359 if (gr1->gr_name == NULL || gr2->gr_name == NULL) { 360 if (gr1->gr_name != gr2->gr_name) 361 return (false); 362 } else if (strcmp(gr1->gr_name, gr2->gr_name) != 0) 363 return (false); 364 if (gr1->gr_passwd == NULL || gr2->gr_passwd == NULL) { 365 if (gr1->gr_passwd != gr2->gr_passwd) 366 return (false); 367 } else if (strcmp(gr1->gr_passwd, gr2->gr_passwd) != 0) 368 return (false); 369 if (gr1->gr_gid != gr2->gr_gid) 370 return (false); 371 372 /* Check all members in both groups. */ 373 if (gr1->gr_mem == NULL || gr2->gr_mem == NULL) { 374 if (gr1->gr_mem != gr2->gr_mem) 375 return (false); 376 } else { 377 for (found = false, gr1_ndx = 0; gr1->gr_mem[gr1_ndx] != NULL; 378 gr1_ndx++) { 379 for (gr2_ndx = 0; gr2->gr_mem[gr2_ndx] != NULL; 380 gr2_ndx++) 381 if (strcmp(gr1->gr_mem[gr1_ndx], 382 gr2->gr_mem[gr2_ndx]) == 0) { 383 found = true; 384 break; 385 } 386 if (!found) 387 return (false); 388 } 389 390 /* Check that group2 does not have more members than group1. */ 391 if (gr2->gr_mem[gr1_ndx] != NULL) 392 return (false); 393 } 394 395 return (true); 396 } 397 398 /* 399 * Make a group line out of a struct group. 400 */ 401 char * 402 gr_make(const struct group *gr) 403 { 404 char *line; 405 size_t line_size; 406 int ndx; 407 408 /* Calculate the length of the group line. */ 409 line_size = snprintf(NULL, 0, group_line_format, gr->gr_name, 410 gr->gr_passwd, (uintmax_t)gr->gr_gid) + 1; 411 if (gr->gr_mem != NULL) { 412 for (ndx = 0; gr->gr_mem[ndx] != NULL; ndx++) 413 line_size += strlen(gr->gr_mem[ndx]) + 1; 414 if (ndx > 0) 415 line_size--; 416 } 417 418 /* Create the group line and fill it. */ 419 if ((line = malloc(line_size)) == NULL) 420 return (NULL); 421 snprintf(line, line_size, group_line_format, gr->gr_name, gr->gr_passwd, 422 (uintmax_t)gr->gr_gid); 423 if (gr->gr_mem != NULL) 424 for (ndx = 0; gr->gr_mem[ndx] != NULL; ndx++) { 425 strcat(line, gr->gr_mem[ndx]); 426 if (gr->gr_mem[ndx + 1] != NULL) 427 strcat(line, ","); 428 } 429 430 return (line); 431 } 432 433 /* 434 * Duplicate a struct group. 435 */ 436 struct group * 437 gr_dup(const struct group *gr) 438 { 439 char *dst; 440 size_t len; 441 struct group_storage *gs; 442 int ndx; 443 int num_mem; 444 445 /* Calculate size of the group. */ 446 len = sizeof(*gs); 447 if (gr->gr_name != NULL) 448 len += strlen(gr->gr_name) + 1; 449 if (gr->gr_passwd != NULL) 450 len += strlen(gr->gr_passwd) + 1; 451 if (gr->gr_mem != NULL) { 452 for (num_mem = 0; gr->gr_mem[num_mem] != NULL; num_mem++) 453 len += strlen(gr->gr_mem[num_mem]) + 1; 454 len += (num_mem + 1) * sizeof(*gr->gr_mem); 455 } else 456 num_mem = -1; 457 458 /* Create new group and copy old group into it. */ 459 if ((gs = calloc(1, len)) == NULL) 460 return (NULL); 461 dst = (char *)&gs->members[num_mem + 1]; 462 if (gr->gr_name != NULL) { 463 gs->gr.gr_name = dst; 464 dst = stpcpy(gs->gr.gr_name, gr->gr_name) + 1; 465 } 466 if (gr->gr_passwd != NULL) { 467 gs->gr.gr_passwd = dst; 468 dst = stpcpy(gs->gr.gr_passwd, gr->gr_passwd) + 1; 469 } 470 gs->gr.gr_gid = gr->gr_gid; 471 if (gr->gr_mem != NULL) { 472 gs->gr.gr_mem = gs->members; 473 for (ndx = 0; ndx < num_mem; ndx++) { 474 gs->gr.gr_mem[ndx] = dst; 475 dst = stpcpy(gs->gr.gr_mem[ndx], gr->gr_mem[ndx]) + 1; 476 } 477 gs->gr.gr_mem[ndx] = NULL; 478 } 479 480 return (&gs->gr); 481 } 482 483 /* 484 * Scan a line and place it into a group structure. 485 */ 486 static bool 487 __gr_scan(char *line, struct group *gr) 488 { 489 char *loc; 490 int ndx; 491 492 /* Assign non-member information to structure. */ 493 gr->gr_name = line; 494 if ((loc = strchr(line, ':')) == NULL) 495 return (false); 496 *loc = '\0'; 497 gr->gr_passwd = loc + 1; 498 if (*gr->gr_passwd == ':') 499 *gr->gr_passwd = '\0'; 500 else { 501 if ((loc = strchr(loc + 1, ':')) == NULL) 502 return (false); 503 *loc = '\0'; 504 } 505 if (sscanf(loc + 1, "%u", &gr->gr_gid) != 1) 506 return (false); 507 508 /* Assign member information to structure. */ 509 if ((loc = strchr(loc + 1, ':')) == NULL) 510 return (false); 511 line = loc + 1; 512 gr->gr_mem = NULL; 513 ndx = 0; 514 do { 515 gr->gr_mem = reallocf(gr->gr_mem, sizeof(*gr->gr_mem) * 516 (ndx + 1)); 517 if (gr->gr_mem == NULL) 518 return (false); 519 520 /* Skip locations without members (i.e., empty string). */ 521 do { 522 gr->gr_mem[ndx] = strsep(&line, ","); 523 } while (gr->gr_mem[ndx] != NULL && *gr->gr_mem[ndx] == '\0'); 524 } while (gr->gr_mem[ndx++] != NULL); 525 526 return (true); 527 } 528 529 /* 530 * Create a struct group from a line. 531 */ 532 struct group * 533 gr_scan(const char *line) 534 { 535 struct group gr; 536 char *line_copy; 537 struct group *new_gr; 538 539 if ((line_copy = strdup(line)) == NULL) 540 return (NULL); 541 if (!__gr_scan(line_copy, &gr)) { 542 free(line_copy); 543 return (NULL); 544 } 545 new_gr = gr_dup(&gr); 546 free(line_copy); 547 if (gr.gr_mem != NULL) 548 free(gr.gr_mem); 549 550 return (new_gr); 551 } 552