1 /* Test whether a file has a nontrivial access control list. 2 3 Copyright (C) 2002-2003, 2005-2009 Free Software Foundation, Inc. 4 5 This program is free software: you can redistribute it and/or modify 6 it under the terms of the GNU General Public License as published by 7 the Free Software Foundation; either version 3 of the License, or 8 (at your option) any later version. 9 10 This program is distributed in the hope that it will be useful, 11 but WITHOUT ANY WARRANTY; without even the implied warranty of 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 GNU General Public License for more details. 14 15 You should have received a copy of the GNU General Public License 16 along with this program. If not, see <http://www.gnu.org/licenses/>. 17 18 Written by Paul Eggert, Andreas Grnbacher, and Bruno Haible. */ 19 20 #include <config.h> 21 22 #include "acl.h" 23 24 #include "acl-internal.h" 25 26 27 #if USE_ACL && HAVE_ACL_GET_FILE 28 29 # if HAVE_ACL_TYPE_EXTENDED /* MacOS X */ 30 31 /* ACL is an ACL, from a file, stored as type ACL_TYPE_EXTENDED. 32 Return 1 if the given ACL is non-trivial. 33 Return 0 if it is trivial. */ 34 int 35 acl_extended_nontrivial (acl_t acl) 36 { 37 /* acl is non-trivial if it is non-empty. */ 38 return (acl_entries (acl) > 0); 39 } 40 41 # else /* Linux, FreeBSD, IRIX, Tru64 */ 42 43 /* ACL is an ACL, from a file, stored as type ACL_TYPE_ACCESS. 44 Return 1 if the given ACL is non-trivial. 45 Return 0 if it is trivial, i.e. equivalent to a simple stat() mode. 46 Return -1 and set errno upon failure to determine it. */ 47 int 48 acl_access_nontrivial (acl_t acl) 49 { 50 /* acl is non-trivial if it has some entries other than for "user::", 51 "group::", and "other::". Normally these three should be present 52 at least, allowing us to write 53 return (3 < acl_entries (acl)); 54 but the following code is more robust. */ 55 # if HAVE_ACL_FIRST_ENTRY /* Linux, FreeBSD */ 56 57 acl_entry_t ace; 58 int got_one; 59 60 for (got_one = acl_get_entry (acl, ACL_FIRST_ENTRY, &ace); 61 got_one > 0; 62 got_one = acl_get_entry (acl, ACL_NEXT_ENTRY, &ace)) 63 { 64 acl_tag_t tag; 65 if (acl_get_tag_type (ace, &tag) < 0) 66 return -1; 67 if (!(tag == ACL_USER_OBJ || tag == ACL_GROUP_OBJ || tag == ACL_OTHER)) 68 return 1; 69 } 70 return got_one; 71 72 # else /* IRIX, Tru64 */ 73 # if HAVE_ACL_TO_SHORT_TEXT /* IRIX */ 74 /* Don't use acl_get_entry: it is undocumented. */ 75 76 int count = acl->acl_cnt; 77 int i; 78 79 for (i = 0; i < count; i++) 80 { 81 acl_entry_t ace = &acl->acl_entry[i]; 82 acl_tag_t tag = ace->ae_tag; 83 84 if (!(tag == ACL_USER_OBJ || tag == ACL_GROUP_OBJ 85 || tag == ACL_OTHER_OBJ)) 86 return 1; 87 } 88 return 0; 89 90 # endif 91 # if HAVE_ACL_FREE_TEXT /* Tru64 */ 92 /* Don't use acl_get_entry: it takes only one argument and does not work. */ 93 94 int count = acl->acl_num; 95 acl_entry_t ace; 96 97 for (ace = acl->acl_first; count > 0; ace = ace->next, count--) 98 { 99 acl_tag_t tag; 100 acl_perm_t perm; 101 102 tag = ace->entry->acl_type; 103 if (!(tag == ACL_USER_OBJ || tag == ACL_GROUP_OBJ || tag == ACL_OTHER)) 104 return 1; 105 106 perm = ace->entry->acl_perm; 107 /* On Tru64, perm can also contain non-standard bits such as 108 PERM_INSERT, PERM_DELETE, PERM_MODIFY, PERM_LOOKUP, ... */ 109 if ((perm & ~(ACL_READ | ACL_WRITE | ACL_EXECUTE)) != 0) 110 return 1; 111 } 112 return 0; 113 114 # endif 115 # endif 116 } 117 118 # endif 119 120 121 #elif USE_ACL && HAVE_ACL && defined GETACL /* Solaris, Cygwin, not HP-UX */ 122 123 # if !defined ACL_NO_TRIVIAL /* Solaris <= 10, Cygwin */ 124 125 /* Test an ACL retrieved with GETACL. 126 Return 1 if the given ACL, consisting of COUNT entries, is non-trivial. 127 Return 0 if it is trivial, i.e. equivalent to a simple stat() mode. */ 128 int 129 acl_nontrivial (int count, aclent_t *entries) 130 { 131 int i; 132 133 for (i = 0; i < count; i++) 134 { 135 aclent_t *ace = &entries[i]; 136 137 /* Note: If ace->a_type = USER_OBJ, ace->a_id is the st_uid from stat(). 138 If ace->a_type = GROUP_OBJ, ace->a_id is the st_gid from stat(). 139 We don't need to check ace->a_id in these cases. */ 140 if (!(ace->a_type == USER_OBJ 141 || ace->a_type == GROUP_OBJ 142 || ace->a_type == OTHER_OBJ 143 /* Note: Cygwin does not return a CLASS_OBJ ("mask:") entry 144 sometimes. */ 145 || ace->a_type == CLASS_OBJ)) 146 return 1; 147 } 148 return 0; 149 } 150 151 # ifdef ACE_GETACL 152 153 /* Test an ACL retrieved with ACE_GETACL. 154 Return 1 if the given ACL, consisting of COUNT entries, is non-trivial. 155 Return 0 if it is trivial, i.e. equivalent to a simple stat() mode. */ 156 int 157 acl_ace_nontrivial (int count, ace_t *entries) 158 { 159 int i; 160 161 /* The flags in the ace_t structure changed in a binary incompatible way 162 when ACL_NO_TRIVIAL etc. were introduced in <sys/acl.h> version 1.15. 163 How to distinguish the two conventions at runtime? 164 In the old convention, usually three ACEs have a_flags = ACE_OWNER / 165 ACE_GROUP / ACE_OTHER, in the range 0x0100..0x0400. In the new 166 convention, these values are not used. */ 167 int old_convention = 0; 168 169 for (i = 0; i < count; i++) 170 if (entries[i].a_flags & (ACE_OWNER | ACE_GROUP | ACE_OTHER)) 171 { 172 old_convention = 1; 173 break; 174 } 175 176 if (old_convention) 177 /* Running on Solaris 10. */ 178 for (i = 0; i < count; i++) 179 { 180 ace_t *ace = &entries[i]; 181 182 /* Note: 183 If ace->a_flags = ACE_OWNER, ace->a_who is the st_uid from stat(). 184 If ace->a_flags = ACE_GROUP, ace->a_who is the st_gid from stat(). 185 We don't need to check ace->a_who in these cases. */ 186 if (!(ace->a_type == ALLOW 187 && (ace->a_flags == ACE_OWNER 188 || ace->a_flags == ACE_GROUP 189 || ace->a_flags == ACE_OTHER))) 190 return 1; 191 } 192 else 193 /* Running on Solaris 10 (newer version) or Solaris 11. */ 194 for (i = 0; i < count; i++) 195 { 196 ace_t *ace = &entries[i]; 197 198 if (!(ace->a_type == ACE_ACCESS_ALLOWED_ACE_TYPE 199 && (ace->a_flags == NEW_ACE_OWNER 200 || ace->a_flags 201 == (NEW_ACE_GROUP | NEW_ACE_IDENTIFIER_GROUP) 202 || ace->a_flags == ACE_EVERYONE) 203 && (ace->a_access_mask 204 & ~(NEW_ACE_READ_DATA | NEW_ACE_WRITE_DATA | NEW_ACE_EXECUTE)) 205 == 0)) 206 return 1; 207 } 208 209 return 0; 210 } 211 212 # endif 213 214 # endif 215 216 #elif USE_ACL && HAVE_GETACL /* HP-UX */ 217 218 /* Return 1 if the given ACL is non-trivial. 219 Return 0 if it is trivial, i.e. equivalent to a simple stat() mode. */ 220 int 221 acl_nontrivial (int count, struct acl_entry *entries, struct stat *sb) 222 { 223 int i; 224 225 for (i = 0; i < count; i++) 226 { 227 struct acl_entry *ace = &entries[i]; 228 229 if (!((ace->uid == sb->st_uid && ace->gid == ACL_NSGROUP) 230 || (ace->uid == ACL_NSUSER && ace->gid == sb->st_gid) 231 || (ace->uid == ACL_NSUSER && ace->gid == ACL_NSGROUP))) 232 return 1; 233 } 234 return 0; 235 } 236 237 #elif USE_ACL && HAVE_ACLX_GET && 0 /* AIX */ 238 239 /* TODO */ 240 241 #elif USE_ACL && HAVE_STATACL /* older AIX */ 242 243 /* Return 1 if the given ACL is non-trivial. 244 Return 0 if it is trivial, i.e. equivalent to a simple stat() mode. */ 245 int 246 acl_nontrivial (struct acl *a) 247 { 248 /* The normal way to iterate through an ACL is like this: 249 struct acl_entry *ace; 250 for (ace = a->acl_ext; ace != acl_last (a); ace = acl_nxt (ace)) 251 { 252 struct ace_id *aei; 253 switch (ace->ace_type) 254 { 255 case ACC_PERMIT: 256 case ACC_DENY: 257 case ACC_SPECIFY: 258 ...; 259 } 260 for (aei = ace->ace_id; aei != id_last (ace); aei = id_nxt (aei)) 261 ... 262 } 263 */ 264 return (acl_last (a) != a->acl_ext ? 1 : 0); 265 } 266 267 #endif 268 269 270 /* Return 1 if NAME has a nontrivial access control list, 0 if NAME 271 only has no or a base access control list, and -1 (setting errno) 272 on error. SB must be set to the stat buffer of FILE. */ 273 274 int 275 file_has_acl (char const *name, struct stat const *sb) 276 { 277 #if USE_ACL 278 if (! S_ISLNK (sb->st_mode)) 279 { 280 # if HAVE_ACL_GET_FILE 281 282 /* POSIX 1003.1e (draft 17 -- abandoned) specific version. */ 283 /* Linux, FreeBSD, MacOS X, IRIX, Tru64 */ 284 int ret; 285 286 if (HAVE_ACL_EXTENDED_FILE) /* Linux */ 287 { 288 /* On Linux, acl_extended_file is an optimized function: It only 289 makes two calls to getxattr(), one for ACL_TYPE_ACCESS, one for 290 ACL_TYPE_DEFAULT. */ 291 ret = acl_extended_file (name); 292 } 293 else /* FreeBSD, MacOS X, IRIX, Tru64 */ 294 { 295 # if HAVE_ACL_TYPE_EXTENDED /* MacOS X */ 296 /* On MacOS X, acl_get_file (name, ACL_TYPE_ACCESS) 297 and acl_get_file (name, ACL_TYPE_DEFAULT) 298 always return NULL / EINVAL. There is no point in making 299 these two useless calls. The real ACL is retrieved through 300 acl_get_file (name, ACL_TYPE_EXTENDED). */ 301 acl_t acl = acl_get_file (name, ACL_TYPE_EXTENDED); 302 if (acl) 303 { 304 ret = acl_extended_nontrivial (acl); 305 acl_free (acl); 306 } 307 else 308 ret = -1; 309 # else /* FreeBSD, IRIX, Tru64 */ 310 acl_t acl = acl_get_file (name, ACL_TYPE_ACCESS); 311 if (acl) 312 { 313 int saved_errno; 314 315 ret = acl_access_nontrivial (acl); 316 saved_errno = errno; 317 acl_free (acl); 318 errno = saved_errno; 319 # if HAVE_ACL_FREE_TEXT /* Tru64 */ 320 /* On OSF/1, acl_get_file (name, ACL_TYPE_DEFAULT) always 321 returns NULL with errno not set. There is no point in 322 making this call. */ 323 # else /* FreeBSD, IRIX */ 324 /* On Linux, FreeBSD, IRIX, acl_get_file (name, ACL_TYPE_ACCESS) 325 and acl_get_file (name, ACL_TYPE_DEFAULT) on a directory 326 either both succeed or both fail; it depends on the 327 filesystem. Therefore there is no point in making the second 328 call if the first one already failed. */ 329 if (ret == 0 && S_ISDIR (sb->st_mode)) 330 { 331 acl = acl_get_file (name, ACL_TYPE_DEFAULT); 332 if (acl) 333 { 334 ret = (0 < acl_entries (acl)); 335 acl_free (acl); 336 } 337 else 338 ret = -1; 339 } 340 # endif 341 } 342 else 343 ret = -1; 344 # endif 345 } 346 if (ret < 0) 347 return ACL_NOT_WELL_SUPPORTED (errno) ? 0 : -1; 348 return ret; 349 350 # elif HAVE_ACL && defined GETACLCNT /* Solaris, Cygwin, not HP-UX */ 351 352 # if defined ACL_NO_TRIVIAL 353 354 /* Solaris 10 (newer version), which has additional API declared in 355 <sys/acl.h> (acl_t) and implemented in libsec (acl_set, acl_trivial, 356 acl_fromtext, ...). */ 357 return acl_trivial (name); 358 359 # else /* Solaris, Cygwin, general case */ 360 361 /* Solaris 2.5 through Solaris 10, Cygwin, and contemporaneous versions 362 of Unixware. The acl() call returns the access and default ACL both 363 at once. */ 364 int count; 365 { 366 aclent_t *entries; 367 368 for (;;) 369 { 370 count = acl (name, GETACLCNT, 0, NULL); 371 372 if (count < 0) 373 { 374 if (errno == ENOSYS || errno == ENOTSUP) 375 break; 376 else 377 return -1; 378 } 379 380 if (count == 0) 381 break; 382 383 /* Don't use MIN_ACL_ENTRIES: It's set to 4 on Cygwin, but Cygwin 384 returns only 3 entries for files with no ACL. But this is safe: 385 If there are more than 4 entries, there cannot be only the 386 "user::", "group::", "other:", and "mask:" entries. */ 387 if (count > 4) 388 return 1; 389 390 entries = (aclent_t *) malloc (count * sizeof (aclent_t)); 391 if (entries == NULL) 392 { 393 errno = ENOMEM; 394 return -1; 395 } 396 if (acl (name, GETACL, count, entries) == count) 397 { 398 if (acl_nontrivial (count, entries)) 399 { 400 free (entries); 401 return 1; 402 } 403 free (entries); 404 break; 405 } 406 /* Huh? The number of ACL entries changed since the last call. 407 Repeat. */ 408 free (entries); 409 } 410 } 411 412 # ifdef ACE_GETACL 413 /* Solaris also has a different variant of ACLs, used in ZFS and NFSv4 414 file systems (whereas the other ones are used in UFS file systems). */ 415 { 416 ace_t *entries; 417 418 for (;;) 419 { 420 count = acl (name, ACE_GETACLCNT, 0, NULL); 421 422 if (count < 0) 423 { 424 if (errno == ENOSYS || errno == EINVAL) 425 break; 426 else 427 return -1; 428 } 429 430 if (count == 0) 431 break; 432 433 /* If there are more than 3 entries, there cannot be only the 434 ACE_OWNER, ACE_GROUP, ACE_OTHER entries. */ 435 if (count > 3) 436 return 1; 437 438 entries = (ace_t *) malloc (count * sizeof (ace_t)); 439 if (entries == NULL) 440 { 441 errno = ENOMEM; 442 return -1; 443 } 444 if (acl (name, ACE_GETACL, count, entries) == count) 445 { 446 if (acl_ace_nontrivial (count, entries)) 447 { 448 free (entries); 449 return 1; 450 } 451 free (entries); 452 break; 453 } 454 /* Huh? The number of ACL entries changed since the last call. 455 Repeat. */ 456 free (entries); 457 } 458 } 459 # endif 460 461 return 0; 462 # endif 463 464 # elif HAVE_GETACL /* HP-UX */ 465 466 int count; 467 struct acl_entry entries[NACLENTRIES]; 468 469 for (;;) 470 { 471 count = getacl (name, 0, NULL); 472 473 if (count < 0) 474 return (errno == ENOSYS || errno == EOPNOTSUPP ? 0 : -1); 475 476 if (count == 0) 477 return 0; 478 479 if (count > NACLENTRIES) 480 /* If NACLENTRIES cannot be trusted, use dynamic memory 481 allocation. */ 482 abort (); 483 484 /* If there are more than 3 entries, there cannot be only the 485 (uid,%), (%,gid), (%,%) entries. */ 486 if (count > 3) 487 return 1; 488 489 if (getacl (name, count, entries) == count) 490 { 491 struct stat statbuf; 492 493 if (stat (name, &statbuf) < 0) 494 return -1; 495 496 return acl_nontrivial (count, entries, &statbuf); 497 } 498 /* Huh? The number of ACL entries changed since the last call. 499 Repeat. */ 500 } 501 502 # elif HAVE_ACLX_GET && 0 /* AIX */ 503 504 /* TODO: use aclx_get(), and then? */ 505 506 # elif HAVE_STATACL /* older AIX */ 507 508 union { struct acl a; char room[4096]; } u; 509 510 if (statacl (name, STX_NORMAL, &u.a, sizeof (u)) < 0) 511 return -1; 512 513 return acl_nontrivial (&u.a); 514 515 # endif 516 } 517 #endif 518 519 return 0; 520 } 521
