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/param.h> 28 #include <sys/errno.h> 29 #include <sys/stat.h> 30 31 #include <ctype.h> 32 #include <err.h> 33 #include <fcntl.h> 34 #include <grp.h> 35 #include <inttypes.h> 36 #include <libutil.h> 37 #include <paths.h> 38 #include <stdbool.h> 39 #include <stdio.h> 40 #include <stdlib.h> 41 #include <string.h> 42 #include <unistd.h> 43 44 struct group_storage { 45 struct group gr; 46 char *members[]; 47 }; 48 49 static int lockfd = -1; 50 static char group_dir[PATH_MAX]; 51 static char group_file[PATH_MAX]; 52 static char tempname[PATH_MAX]; 53 static int initialized; 54 55 static const char group_line_format[] = "%s:%s:%ju:"; 56 57 /* 58 * Initialize statics 59 */ 60 int 61 gr_init(const char *dir, const char *group) 62 { 63 64 if (dir == NULL) { 65 strcpy(group_dir, _PATH_ETC); 66 } else { 67 if (strlen(dir) >= sizeof(group_dir)) { 68 errno = ENAMETOOLONG; 69 return (-1); 70 } 71 strcpy(group_dir, dir); 72 } 73 74 if (group == NULL) { 75 if (dir == NULL) { 76 strcpy(group_file, _PATH_GROUP); 77 } else if (snprintf(group_file, sizeof(group_file), "%s/group", 78 group_dir) > (int)sizeof(group_file)) { 79 errno = ENAMETOOLONG; 80 return (-1); 81 } 82 } else { 83 if (strlen(group) >= sizeof(group_file)) { 84 errno = ENAMETOOLONG; 85 return (-1); 86 } 87 strcpy(group_file, group); 88 } 89 90 initialized = 1; 91 return (0); 92 } 93 94 /* 95 * Lock the group file 96 */ 97 int 98 gr_lock(void) 99 { 100 if (*group_file == '\0') 101 return (-1); 102 103 for (;;) { 104 struct stat st; 105 106 lockfd = open(group_file, O_RDONLY, 0); 107 if (lockfd < 0 || fcntl(lockfd, F_SETFD, 1) == -1) 108 err(1, "%s", group_file); 109 if (flock(lockfd, LOCK_EX|LOCK_NB) == -1) { 110 if (errno == EWOULDBLOCK) { 111 errx(1, "the group file is busy"); 112 } else { 113 err(1, "could not lock the group file: "); 114 } 115 } 116 if (fstat(lockfd, &st) == -1) 117 err(1, "fstat() failed: "); 118 if (st.st_nlink != 0) 119 break; 120 close(lockfd); 121 lockfd = -1; 122 } 123 return (lockfd); 124 } 125 126 /* 127 * Create and open a presmuably safe temp file for editing group data 128 */ 129 int 130 gr_tmp(int mfd) 131 { 132 char buf[8192]; 133 ssize_t nr; 134 const char *p; 135 int tfd; 136 137 if (*group_file == '\0') 138 return (-1); 139 if ((p = strrchr(group_file, '/'))) 140 ++p; 141 else 142 p = group_file; 143 if (snprintf(tempname, sizeof(tempname), "%.*sgroup.XXXXXX", 144 (int)(p - group_file), group_file) >= (int)sizeof(tempname)) { 145 errno = ENAMETOOLONG; 146 return (-1); 147 } 148 if ((tfd = mkstemp(tempname)) == -1) 149 return (-1); 150 if (mfd != -1) { 151 while ((nr = read(mfd, buf, sizeof(buf))) > 0) 152 if (write(tfd, buf, (size_t)nr) != nr) 153 break; 154 if (nr != 0) { 155 unlink(tempname); 156 *tempname = '\0'; 157 close(tfd); 158 return (-1); 159 } 160 } 161 return (tfd); 162 } 163 164 /* 165 * Copy the group file from one descriptor to another, replacing, deleting 166 * or adding a single record on the way. 167 */ 168 int 169 gr_copy(int ffd, int tfd, const struct group *gr, struct group *old_gr) 170 { 171 char buf[8192], *end, *line, *p, *q, *r, t; 172 struct group *fgr; 173 const struct group *sgr; 174 size_t len; 175 int eof, readlen; 176 177 sgr = gr; 178 if (gr == NULL) { 179 line = NULL; 180 if (old_gr == NULL) 181 return (-1); 182 sgr = old_gr; 183 } else if ((line = gr_make(gr)) == NULL) 184 return (-1); 185 186 eof = 0; 187 len = 0; 188 p = q = end = buf; 189 for (;;) { 190 /* find the end of the current line */ 191 for (p = q; q < end && *q != '\0'; ++q) 192 if (*q == '\n') 193 break; 194 195 /* if we don't have a complete line, fill up the buffer */ 196 if (q >= end) { 197 if (eof) 198 break; 199 if ((size_t)(q - p) >= sizeof(buf)) { 200 warnx("group line too long"); 201 errno = EINVAL; /* hack */ 202 goto err; 203 } 204 if (p < end) { 205 q = memmove(buf, p, end -p); 206 end -= p - buf; 207 } else { 208 p = q = end = buf; 209 } 210 readlen = read(ffd, end, sizeof(buf) - (end -buf)); 211 if (readlen == -1) 212 goto err; 213 else 214 len = (size_t)readlen; 215 if (len == 0 && p == buf) 216 break; 217 end += len; 218 len = end - buf; 219 if (len < (ssize_t)sizeof(buf)) { 220 eof = 1; 221 if (len > 0 && buf[len -1] != '\n') 222 ++len, *end++ = '\n'; 223 } 224 continue; 225 } 226 227 /* is it a blank line or a comment? */ 228 for (r = p; r < q && isspace(*r); ++r) 229 /* nothing */; 230 if (r == q || *r == '#') { 231 /* yep */ 232 if (write(tfd, p, q -p + 1) != q - p + 1) 233 goto err; 234 ++q; 235 continue; 236 } 237 238 /* is it the one we're looking for? */ 239 240 t = *q; 241 *q = '\0'; 242 243 fgr = gr_scan(r); 244 245 /* fgr is either a struct group for the current line, 246 * or NULL if the line is malformed. 247 */ 248 249 *q = t; 250 if (fgr == NULL || fgr->gr_gid != sgr->gr_gid) { 251 /* nope */ 252 if (fgr != NULL) 253 free(fgr); 254 if (write(tfd, p, q - p + 1) != q - p + 1) 255 goto err; 256 ++q; 257 continue; 258 } 259 if (old_gr && !gr_equal(fgr, old_gr)) { 260 warnx("entry inconsistent"); 261 free(fgr); 262 errno = EINVAL; /* hack */ 263 goto err; 264 } 265 free(fgr); 266 267 /* it is, replace or remove it */ 268 if (line != NULL) { 269 len = strlen(line); 270 if (write(tfd, line, len) != (int) len) 271 goto err; 272 } else { 273 /* when removed, avoid the \n */ 274 q++; 275 } 276 /* we're done, just copy the rest over */ 277 for (;;) { 278 if (write(tfd, q, end - q) != end - q) 279 goto err; 280 q = buf; 281 readlen = read(ffd, buf, sizeof(buf)); 282 if (readlen == 0) 283 break; 284 else 285 len = (size_t)readlen; 286 if (readlen == -1) 287 goto err; 288 end = buf + len; 289 } 290 goto done; 291 } 292 293 /* if we got here, we didn't find the old entry */ 294 if (line == NULL) { 295 errno = ENOENT; 296 goto err; 297 } 298 len = strlen(line); 299 if ((size_t)write(tfd, line, len) != len || 300 write(tfd, "\n", 1) != 1) 301 goto err; 302 done: 303 if (line != NULL) 304 free(line); 305 return (0); 306 err: 307 if (line != NULL) 308 free(line); 309 return (-1); 310 } 311 312 /* 313 * Regenerate the group file 314 */ 315 int 316 gr_mkdb(void) 317 { 318 return (rename(tempname, group_file)); 319 } 320 321 /* 322 * Clean up. Preserver errno for the caller's convenience. 323 */ 324 void 325 gr_fini(void) 326 { 327 int serrno; 328 329 if (!initialized) 330 return; 331 initialized = 0; 332 serrno = errno; 333 if (*tempname != '\0') { 334 unlink(tempname); 335 *tempname = '\0'; 336 } 337 if (lockfd != -1) 338 close(lockfd); 339 errno = serrno; 340 } 341 342 /* 343 * Compares two struct group's. 344 */ 345 int 346 gr_equal(const struct group *gr1, const struct group *gr2) 347 { 348 int gr1_ndx; 349 int gr2_ndx; 350 bool found; 351 352 /* Check that the non-member information is the same. */ 353 if (gr1->gr_name == NULL || gr2->gr_name == NULL) { 354 if (gr1->gr_name != gr2->gr_name) 355 return (false); 356 } else if (strcmp(gr1->gr_name, gr2->gr_name) != 0) 357 return (false); 358 if (gr1->gr_passwd == NULL || gr2->gr_passwd == NULL) { 359 if (gr1->gr_passwd != gr2->gr_passwd) 360 return (false); 361 } else if (strcmp(gr1->gr_passwd, gr2->gr_passwd) != 0) 362 return (false); 363 if (gr1->gr_gid != gr2->gr_gid) 364 return (false); 365 366 /* Check all members in both groups. */ 367 if (gr1->gr_mem == NULL || gr2->gr_mem == NULL) { 368 if (gr1->gr_mem != gr2->gr_mem) 369 return (false); 370 } else { 371 for (found = false, gr1_ndx = 0; gr1->gr_mem[gr1_ndx] != NULL; 372 gr1_ndx++) { 373 for (gr2_ndx = 0; gr2->gr_mem[gr2_ndx] != NULL; 374 gr2_ndx++) 375 if (strcmp(gr1->gr_mem[gr1_ndx], 376 gr2->gr_mem[gr2_ndx]) == 0) { 377 found = true; 378 break; 379 } 380 if (!found) 381 return (false); 382 } 383 384 /* Check that group2 does not have more members than group1. */ 385 if (gr2->gr_mem[gr1_ndx] != NULL) 386 return (false); 387 } 388 389 return (true); 390 } 391 392 /* 393 * Make a group line out of a struct group. 394 */ 395 char * 396 gr_make(const struct group *gr) 397 { 398 char *line; 399 size_t line_size; 400 int ndx; 401 402 /* Calculate the length of the group line. */ 403 line_size = snprintf(NULL, 0, group_line_format, gr->gr_name, 404 gr->gr_passwd, (uintmax_t)gr->gr_gid) + 1; 405 if (gr->gr_mem != NULL) { 406 for (ndx = 0; gr->gr_mem[ndx] != NULL; ndx++) 407 line_size += strlen(gr->gr_mem[ndx]) + 1; 408 if (ndx > 0) 409 line_size--; 410 } 411 412 /* Create the group line and fill it. */ 413 if ((line = malloc(line_size)) == NULL) 414 return (NULL); 415 snprintf(line, line_size, group_line_format, gr->gr_name, gr->gr_passwd, 416 (uintmax_t)gr->gr_gid); 417 if (gr->gr_mem != NULL) 418 for (ndx = 0; gr->gr_mem[ndx] != NULL; ndx++) { 419 strcat(line, gr->gr_mem[ndx]); 420 if (gr->gr_mem[ndx + 1] != NULL) 421 strcat(line, ","); 422 } 423 424 return (line); 425 } 426 427 /* 428 * Duplicate a struct group. 429 */ 430 struct group * 431 gr_dup(const struct group *gr) 432 { 433 char *dst; 434 size_t len; 435 struct group_storage *gs; 436 int ndx; 437 int num_mem; 438 439 /* Calculate size of the group. */ 440 len = sizeof(*gs); 441 if (gr->gr_name != NULL) 442 len += strlen(gr->gr_name) + 1; 443 if (gr->gr_passwd != NULL) 444 len += strlen(gr->gr_passwd) + 1; 445 if (gr->gr_mem != NULL) { 446 for (num_mem = 0; gr->gr_mem[num_mem] != NULL; num_mem++) 447 len += strlen(gr->gr_mem[num_mem]) + 1; 448 len += (num_mem + 1) * sizeof(*gr->gr_mem); 449 } else 450 num_mem = -1; 451 452 /* Create new group and copy old group into it. */ 453 if ((gs = calloc(1, len)) == NULL) 454 return (NULL); 455 dst = (char *)&gs->members[num_mem + 1]; 456 if (gr->gr_name != NULL) { 457 gs->gr.gr_name = dst; 458 dst = stpcpy(gs->gr.gr_name, gr->gr_name) + 1; 459 } 460 if (gr->gr_passwd != NULL) { 461 gs->gr.gr_passwd = dst; 462 dst = stpcpy(gs->gr.gr_passwd, gr->gr_passwd) + 1; 463 } 464 gs->gr.gr_gid = gr->gr_gid; 465 if (gr->gr_mem != NULL) { 466 gs->gr.gr_mem = gs->members; 467 for (ndx = 0; ndx < num_mem; ndx++) { 468 gs->gr.gr_mem[ndx] = dst; 469 dst = stpcpy(gs->gr.gr_mem[ndx], gr->gr_mem[ndx]) + 1; 470 } 471 gs->gr.gr_mem[ndx] = NULL; 472 } 473 474 return (&gs->gr); 475 } 476 477 /* 478 * Scan a line and place it into a group structure. 479 */ 480 static bool 481 __gr_scan(char *line, struct group *gr) 482 { 483 char *loc; 484 int ndx; 485 486 /* Assign non-member information to structure. */ 487 gr->gr_name = line; 488 if ((loc = strchr(line, ':')) == NULL) 489 return (false); 490 *loc = '\0'; 491 gr->gr_passwd = loc + 1; 492 if (*gr->gr_passwd == ':') 493 *gr->gr_passwd = '\0'; 494 else { 495 if ((loc = strchr(loc + 1, ':')) == NULL) 496 return (false); 497 *loc = '\0'; 498 } 499 if (sscanf(loc + 1, "%u", &gr->gr_gid) != 1) 500 return (false); 501 502 /* Assign member information to structure. */ 503 if ((loc = strchr(loc + 1, ':')) == NULL) 504 return (false); 505 line = loc + 1; 506 gr->gr_mem = NULL; 507 ndx = 0; 508 do { 509 gr->gr_mem = reallocf(gr->gr_mem, sizeof(*gr->gr_mem) * 510 (ndx + 1)); 511 if (gr->gr_mem == NULL) 512 return (false); 513 514 /* Skip locations without members (i.e., empty string). */ 515 do { 516 gr->gr_mem[ndx] = strsep(&line, ","); 517 } while (gr->gr_mem[ndx] != NULL && *gr->gr_mem[ndx] == '\0'); 518 } while (gr->gr_mem[ndx++] != NULL); 519 520 return (true); 521 } 522 523 /* 524 * Create a struct group from a line. 525 */ 526 struct group * 527 gr_scan(const char *line) 528 { 529 struct group gr; 530 char *line_copy; 531 struct group *new_gr; 532 533 if ((line_copy = strdup(line)) == NULL) 534 return (NULL); 535 if (!__gr_scan(line_copy, &gr)) { 536 free(line_copy); 537 return (NULL); 538 } 539 new_gr = gr_dup(&gr); 540 free(line_copy); 541 if (gr.gr_mem != NULL) 542 free(gr.gr_mem); 543 544 return (new_gr); 545 } 546