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