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 return (rename(tempname, group_file)); 322 } 323 324 /* 325 * Clean up. Preserver errno for the caller's convenience. 326 */ 327 void 328 gr_fini(void) 329 { 330 int serrno; 331 332 if (!initialized) 333 return; 334 initialized = 0; 335 serrno = errno; 336 if (*tempname != '\0') { 337 unlink(tempname); 338 *tempname = '\0'; 339 } 340 if (lockfd != -1) 341 close(lockfd); 342 errno = serrno; 343 } 344 345 /* 346 * Compares two struct group's. 347 */ 348 int 349 gr_equal(const struct group *gr1, const struct group *gr2) 350 { 351 int gr1_ndx; 352 int gr2_ndx; 353 bool found; 354 355 /* Check that the non-member information is the same. */ 356 if (gr1->gr_name == NULL || gr2->gr_name == NULL) { 357 if (gr1->gr_name != gr2->gr_name) 358 return (false); 359 } else if (strcmp(gr1->gr_name, gr2->gr_name) != 0) 360 return (false); 361 if (gr1->gr_passwd == NULL || gr2->gr_passwd == NULL) { 362 if (gr1->gr_passwd != gr2->gr_passwd) 363 return (false); 364 } else if (strcmp(gr1->gr_passwd, gr2->gr_passwd) != 0) 365 return (false); 366 if (gr1->gr_gid != gr2->gr_gid) 367 return (false); 368 369 /* Check all members in both groups. */ 370 if (gr1->gr_mem == NULL || gr2->gr_mem == NULL) { 371 if (gr1->gr_mem != gr2->gr_mem) 372 return (false); 373 } else { 374 for (found = false, gr1_ndx = 0; gr1->gr_mem[gr1_ndx] != NULL; 375 gr1_ndx++) { 376 for (gr2_ndx = 0; gr2->gr_mem[gr2_ndx] != NULL; 377 gr2_ndx++) 378 if (strcmp(gr1->gr_mem[gr1_ndx], 379 gr2->gr_mem[gr2_ndx]) == 0) { 380 found = true; 381 break; 382 } 383 if (!found) 384 return (false); 385 } 386 387 /* Check that group2 does not have more members than group1. */ 388 if (gr2->gr_mem[gr1_ndx] != NULL) 389 return (false); 390 } 391 392 return (true); 393 } 394 395 /* 396 * Make a group line out of a struct group. 397 */ 398 char * 399 gr_make(const struct group *gr) 400 { 401 char *line; 402 size_t line_size; 403 int ndx; 404 405 /* Calculate the length of the group line. */ 406 line_size = snprintf(NULL, 0, group_line_format, gr->gr_name, 407 gr->gr_passwd, (uintmax_t)gr->gr_gid) + 1; 408 if (gr->gr_mem != NULL) { 409 for (ndx = 0; gr->gr_mem[ndx] != NULL; ndx++) 410 line_size += strlen(gr->gr_mem[ndx]) + 1; 411 if (ndx > 0) 412 line_size--; 413 } 414 415 /* Create the group line and fill it. */ 416 if ((line = malloc(line_size)) == NULL) 417 return (NULL); 418 snprintf(line, line_size, group_line_format, gr->gr_name, gr->gr_passwd, 419 (uintmax_t)gr->gr_gid); 420 if (gr->gr_mem != NULL) 421 for (ndx = 0; gr->gr_mem[ndx] != NULL; ndx++) { 422 strcat(line, gr->gr_mem[ndx]); 423 if (gr->gr_mem[ndx + 1] != NULL) 424 strcat(line, ","); 425 } 426 427 return (line); 428 } 429 430 /* 431 * Duplicate a struct group. 432 */ 433 struct group * 434 gr_dup(const struct group *gr) 435 { 436 char *dst; 437 size_t len; 438 struct group_storage *gs; 439 int ndx; 440 int num_mem; 441 442 /* Calculate size of the group. */ 443 len = sizeof(*gs); 444 if (gr->gr_name != NULL) 445 len += strlen(gr->gr_name) + 1; 446 if (gr->gr_passwd != NULL) 447 len += strlen(gr->gr_passwd) + 1; 448 if (gr->gr_mem != NULL) { 449 for (num_mem = 0; gr->gr_mem[num_mem] != NULL; num_mem++) 450 len += strlen(gr->gr_mem[num_mem]) + 1; 451 len += (num_mem + 1) * sizeof(*gr->gr_mem); 452 } else 453 num_mem = -1; 454 455 /* Create new group and copy old group into it. */ 456 if ((gs = calloc(1, len)) == NULL) 457 return (NULL); 458 dst = (char *)&gs->members[num_mem + 1]; 459 if (gr->gr_name != NULL) { 460 gs->gr.gr_name = dst; 461 dst = stpcpy(gs->gr.gr_name, gr->gr_name) + 1; 462 } 463 if (gr->gr_passwd != NULL) { 464 gs->gr.gr_passwd = dst; 465 dst = stpcpy(gs->gr.gr_passwd, gr->gr_passwd) + 1; 466 } 467 gs->gr.gr_gid = gr->gr_gid; 468 if (gr->gr_mem != NULL) { 469 gs->gr.gr_mem = gs->members; 470 for (ndx = 0; ndx < num_mem; ndx++) { 471 gs->gr.gr_mem[ndx] = dst; 472 dst = stpcpy(gs->gr.gr_mem[ndx], gr->gr_mem[ndx]) + 1; 473 } 474 gs->gr.gr_mem[ndx] = NULL; 475 } 476 477 return (&gs->gr); 478 } 479 480 /* 481 * Scan a line and place it into a group structure. 482 */ 483 static bool 484 __gr_scan(char *line, struct group *gr) 485 { 486 char *loc; 487 int ndx; 488 489 /* Assign non-member information to structure. */ 490 gr->gr_name = line; 491 if ((loc = strchr(line, ':')) == NULL) 492 return (false); 493 *loc = '\0'; 494 gr->gr_passwd = loc + 1; 495 if (*gr->gr_passwd == ':') 496 *gr->gr_passwd = '\0'; 497 else { 498 if ((loc = strchr(loc + 1, ':')) == NULL) 499 return (false); 500 *loc = '\0'; 501 } 502 if (sscanf(loc + 1, "%u", &gr->gr_gid) != 1) 503 return (false); 504 505 /* Assign member information to structure. */ 506 if ((loc = strchr(loc + 1, ':')) == NULL) 507 return (false); 508 line = loc + 1; 509 gr->gr_mem = NULL; 510 ndx = 0; 511 do { 512 gr->gr_mem = reallocf(gr->gr_mem, sizeof(*gr->gr_mem) * 513 (ndx + 1)); 514 if (gr->gr_mem == NULL) 515 return (false); 516 517 /* Skip locations without members (i.e., empty string). */ 518 do { 519 gr->gr_mem[ndx] = strsep(&line, ","); 520 } while (gr->gr_mem[ndx] != NULL && *gr->gr_mem[ndx] == '\0'); 521 } while (gr->gr_mem[ndx++] != NULL); 522 523 return (true); 524 } 525 526 /* 527 * Create a struct group from a line. 528 */ 529 struct group * 530 gr_scan(const char *line) 531 { 532 struct group gr; 533 char *line_copy; 534 struct group *new_gr; 535 536 if ((line_copy = strdup(line)) == NULL) 537 return (NULL); 538 if (!__gr_scan(line_copy, &gr)) { 539 free(line_copy); 540 return (NULL); 541 } 542 new_gr = gr_dup(&gr); 543 free(line_copy); 544 if (gr.gr_mem != NULL) 545 free(gr.gr_mem); 546 547 return (new_gr); 548 } 549