FreeBSD/Linux Kernel Cross Reference
sys/kern/vfs_acl.c
1 /*-
2 * Copyright (c) 1999-2006 Robert N. M. Watson
3 * All rights reserved.
4 *
5 * This software was developed by Robert Watson for the TrustedBSD Project.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28 /*
29 * Developed by the TrustedBSD Project.
30 *
31 * ACL system calls and other functions common across different ACL types.
32 * Type-specific routines go into subr_acl_<type>.c.
33 */
34
35 #include <sys/cdefs.h>
36 __FBSDID("$FreeBSD$");
37
38 #include <sys/param.h>
39 #include <sys/systm.h>
40 #include <sys/sysproto.h>
41 #include <sys/fcntl.h>
42 #include <sys/kernel.h>
43 #include <sys/malloc.h>
44 #include <sys/mount.h>
45 #include <sys/vnode.h>
46 #include <sys/lock.h>
47 #include <sys/mutex.h>
48 #include <sys/namei.h>
49 #include <sys/file.h>
50 #include <sys/filedesc.h>
51 #include <sys/proc.h>
52 #include <sys/sysent.h>
53 #include <sys/acl.h>
54
55 #include <security/mac/mac_framework.h>
56
57 CTASSERT(ACL_MAX_ENTRIES >= OLDACL_MAX_ENTRIES);
58
59 MALLOC_DEFINE(M_ACL, "acl", "Access Control Lists");
60
61 static int vacl_set_acl(struct thread *td, struct vnode *vp,
62 acl_type_t type, struct acl *aclp);
63 static int vacl_get_acl(struct thread *td, struct vnode *vp,
64 acl_type_t type, struct acl *aclp);
65 static int vacl_aclcheck(struct thread *td, struct vnode *vp,
66 acl_type_t type, struct acl *aclp);
67
68 int
69 acl_copy_oldacl_into_acl(const struct oldacl *source, struct acl *dest)
70 {
71 int i;
72
73 if (source->acl_cnt < 0 || source->acl_cnt > OLDACL_MAX_ENTRIES)
74 return (EINVAL);
75
76 bzero(dest, sizeof(*dest));
77
78 dest->acl_cnt = source->acl_cnt;
79 dest->acl_maxcnt = ACL_MAX_ENTRIES;
80
81 for (i = 0; i < dest->acl_cnt; i++) {
82 dest->acl_entry[i].ae_tag = source->acl_entry[i].ae_tag;
83 dest->acl_entry[i].ae_id = source->acl_entry[i].ae_id;
84 dest->acl_entry[i].ae_perm = source->acl_entry[i].ae_perm;
85 }
86
87 return (0);
88 }
89
90 int
91 acl_copy_acl_into_oldacl(const struct acl *source, struct oldacl *dest)
92 {
93 int i;
94
95 if (source->acl_cnt < 0 || source->acl_cnt > OLDACL_MAX_ENTRIES)
96 return (EINVAL);
97
98 bzero(dest, sizeof(*dest));
99
100 dest->acl_cnt = source->acl_cnt;
101
102 for (i = 0; i < dest->acl_cnt; i++) {
103 dest->acl_entry[i].ae_tag = source->acl_entry[i].ae_tag;
104 dest->acl_entry[i].ae_id = source->acl_entry[i].ae_id;
105 dest->acl_entry[i].ae_perm = source->acl_entry[i].ae_perm;
106 }
107
108 return (0);
109 }
110
111 /*
112 * At one time, "struct ACL" was extended in order to add support for NFSv4
113 * ACLs. Instead of creating compatibility versions of all the ACL-related
114 * syscalls, they were left intact. It's possible to find out what the code
115 * calling these syscalls (libc) expects basing on "type" argument - if it's
116 * either ACL_TYPE_ACCESS_OLD or ACL_TYPE_DEFAULT_OLD (which previously were
117 * known as ACL_TYPE_ACCESS and ACL_TYPE_DEFAULT), then it's the "struct
118 * oldacl". If it's something else, then it's the new "struct acl". In the
119 * latter case, the routines below just copyin/copyout the contents. In the
120 * former case, they copyin the "struct oldacl" and convert it to the new
121 * format.
122 */
123 static int
124 acl_copyin(void *user_acl, struct acl *kernel_acl, acl_type_t type)
125 {
126 int error;
127 struct oldacl old;
128
129 switch (type) {
130 case ACL_TYPE_ACCESS_OLD:
131 case ACL_TYPE_DEFAULT_OLD:
132 error = copyin(user_acl, &old, sizeof(old));
133 if (error != 0)
134 break;
135 acl_copy_oldacl_into_acl(&old, kernel_acl);
136 break;
137
138 default:
139 error = copyin(user_acl, kernel_acl, sizeof(*kernel_acl));
140 if (kernel_acl->acl_maxcnt != ACL_MAX_ENTRIES)
141 return (EINVAL);
142 }
143
144 return (error);
145 }
146
147 static int
148 acl_copyout(struct acl *kernel_acl, void *user_acl, acl_type_t type)
149 {
150 int error;
151 struct oldacl old;
152
153 switch (type) {
154 case ACL_TYPE_ACCESS_OLD:
155 case ACL_TYPE_DEFAULT_OLD:
156 error = acl_copy_acl_into_oldacl(kernel_acl, &old);
157 if (error != 0)
158 break;
159
160 error = copyout(&old, user_acl, sizeof(old));
161 break;
162
163 default:
164 if (fuword32((char *)user_acl +
165 offsetof(struct acl, acl_maxcnt)) != ACL_MAX_ENTRIES)
166 return (EINVAL);
167
168 error = copyout(kernel_acl, user_acl, sizeof(*kernel_acl));
169 }
170
171 return (error);
172 }
173
174 /*
175 * Convert "old" type - ACL_TYPE_{ACCESS,DEFAULT}_OLD - into its "new"
176 * counterpart. It's required for old (pre-NFSv4 ACLs) libc to work
177 * with new kernel. Fixing 'type' for old binaries with new libc
178 * is being done in lib/libc/posix1e/acl_support.c:_acl_type_unold().
179 */
180 static int
181 acl_type_unold(int type)
182 {
183 switch (type) {
184 case ACL_TYPE_ACCESS_OLD:
185 return (ACL_TYPE_ACCESS);
186
187 case ACL_TYPE_DEFAULT_OLD:
188 return (ACL_TYPE_DEFAULT);
189
190 default:
191 return (type);
192 }
193 }
194
195 /*
196 * These calls wrap the real vnode operations, and are called by the syscall
197 * code once the syscall has converted the path or file descriptor to a vnode
198 * (unlocked). The aclp pointer is assumed still to point to userland, so
199 * this should not be consumed within the kernel except by syscall code.
200 * Other code should directly invoke VOP_{SET,GET}ACL.
201 */
202
203 /*
204 * Given a vnode, set its ACL.
205 */
206 static int
207 vacl_set_acl(struct thread *td, struct vnode *vp, acl_type_t type,
208 struct acl *aclp)
209 {
210 struct acl *inkernelacl;
211 struct mount *mp;
212 int error;
213
214 inkernelacl = acl_alloc(M_WAITOK);
215 error = acl_copyin(aclp, inkernelacl, type);
216 if (error)
217 goto out;
218 error = vn_start_write(vp, &mp, V_WAIT | PCATCH);
219 if (error != 0)
220 goto out;
221 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
222 #ifdef MAC
223 error = mac_vnode_check_setacl(td->td_ucred, vp, type, inkernelacl);
224 if (error != 0)
225 goto out_unlock;
226 #endif
227 error = VOP_SETACL(vp, acl_type_unold(type), inkernelacl,
228 td->td_ucred, td);
229 #ifdef MAC
230 out_unlock:
231 #endif
232 VOP_UNLOCK(vp, 0);
233 vn_finished_write(mp);
234 out:
235 acl_free(inkernelacl);
236 return(error);
237 }
238
239 /*
240 * Given a vnode, get its ACL.
241 */
242 static int
243 vacl_get_acl(struct thread *td, struct vnode *vp, acl_type_t type,
244 struct acl *aclp)
245 {
246 struct acl *inkernelacl;
247 int error;
248
249 inkernelacl = acl_alloc(M_WAITOK | M_ZERO);
250 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
251 #ifdef MAC
252 error = mac_vnode_check_getacl(td->td_ucred, vp, type);
253 if (error != 0)
254 goto out;
255 #endif
256 error = VOP_GETACL(vp, acl_type_unold(type), inkernelacl,
257 td->td_ucred, td);
258
259 #ifdef MAC
260 out:
261 #endif
262 VOP_UNLOCK(vp, 0);
263 if (error == 0)
264 error = acl_copyout(inkernelacl, aclp, type);
265 acl_free(inkernelacl);
266 return (error);
267 }
268
269 /*
270 * Given a vnode, delete its ACL.
271 */
272 static int
273 vacl_delete(struct thread *td, struct vnode *vp, acl_type_t type)
274 {
275 struct mount *mp;
276 int error;
277
278 error = vn_start_write(vp, &mp, V_WAIT | PCATCH);
279 if (error)
280 return (error);
281 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
282 #ifdef MAC
283 error = mac_vnode_check_deleteacl(td->td_ucred, vp, type);
284 if (error)
285 goto out;
286 #endif
287 error = VOP_SETACL(vp, acl_type_unold(type), 0, td->td_ucred, td);
288 #ifdef MAC
289 out:
290 #endif
291 VOP_UNLOCK(vp, 0);
292 vn_finished_write(mp);
293 return (error);
294 }
295
296 /*
297 * Given a vnode, check whether an ACL is appropriate for it
298 */
299 static int
300 vacl_aclcheck(struct thread *td, struct vnode *vp, acl_type_t type,
301 struct acl *aclp)
302 {
303 struct acl *inkernelacl;
304 int error;
305
306 inkernelacl = acl_alloc(M_WAITOK);
307 error = acl_copyin(aclp, inkernelacl, type);
308 if (error)
309 goto out;
310 error = VOP_ACLCHECK(vp, acl_type_unold(type), inkernelacl,
311 td->td_ucred, td);
312 out:
313 acl_free(inkernelacl);
314 return (error);
315 }
316
317 /*
318 * syscalls -- convert the path/fd to a vnode, and call vacl_whatever. Don't
319 * need to lock, as the vacl_ code will get/release any locks required.
320 */
321
322 /*
323 * Given a file path, get an ACL for it
324 */
325 int
326 __acl_get_file(struct thread *td, struct __acl_get_file_args *uap)
327 {
328 struct nameidata nd;
329 int vfslocked, error;
330
331 NDINIT(&nd, LOOKUP, MPSAFE|FOLLOW, UIO_USERSPACE, uap->path, td);
332 error = namei(&nd);
333 vfslocked = NDHASGIANT(&nd);
334 if (error == 0) {
335 error = vacl_get_acl(td, nd.ni_vp, uap->type, uap->aclp);
336 NDFREE(&nd, 0);
337 }
338 VFS_UNLOCK_GIANT(vfslocked);
339 return (error);
340 }
341
342 /*
343 * Given a file path, get an ACL for it; don't follow links.
344 */
345 int
346 __acl_get_link(struct thread *td, struct __acl_get_link_args *uap)
347 {
348 struct nameidata nd;
349 int vfslocked, error;
350
351 NDINIT(&nd, LOOKUP, MPSAFE|NOFOLLOW, UIO_USERSPACE, uap->path, td);
352 error = namei(&nd);
353 vfslocked = NDHASGIANT(&nd);
354 if (error == 0) {
355 error = vacl_get_acl(td, nd.ni_vp, uap->type, uap->aclp);
356 NDFREE(&nd, 0);
357 }
358 VFS_UNLOCK_GIANT(vfslocked);
359 return (error);
360 }
361
362 /*
363 * Given a file path, set an ACL for it.
364 */
365 int
366 __acl_set_file(struct thread *td, struct __acl_set_file_args *uap)
367 {
368 struct nameidata nd;
369 int vfslocked, error;
370
371 NDINIT(&nd, LOOKUP, MPSAFE|FOLLOW, UIO_USERSPACE, uap->path, td);
372 error = namei(&nd);
373 vfslocked = NDHASGIANT(&nd);
374 if (error == 0) {
375 error = vacl_set_acl(td, nd.ni_vp, uap->type, uap->aclp);
376 NDFREE(&nd, 0);
377 }
378 VFS_UNLOCK_GIANT(vfslocked);
379 return (error);
380 }
381
382 /*
383 * Given a file path, set an ACL for it; don't follow links.
384 */
385 int
386 __acl_set_link(struct thread *td, struct __acl_set_link_args *uap)
387 {
388 struct nameidata nd;
389 int vfslocked, error;
390
391 NDINIT(&nd, LOOKUP, MPSAFE|NOFOLLOW, UIO_USERSPACE, uap->path, td);
392 error = namei(&nd);
393 vfslocked = NDHASGIANT(&nd);
394 if (error == 0) {
395 error = vacl_set_acl(td, nd.ni_vp, uap->type, uap->aclp);
396 NDFREE(&nd, 0);
397 }
398 VFS_UNLOCK_GIANT(vfslocked);
399 return (error);
400 }
401
402 /*
403 * Given a file descriptor, get an ACL for it.
404 */
405 int
406 __acl_get_fd(struct thread *td, struct __acl_get_fd_args *uap)
407 {
408 struct file *fp;
409 int vfslocked, error;
410
411 error = getvnode(td->td_proc->p_fd, uap->filedes, &fp);
412 if (error == 0) {
413 vfslocked = VFS_LOCK_GIANT(fp->f_vnode->v_mount);
414 error = vacl_get_acl(td, fp->f_vnode, uap->type, uap->aclp);
415 fdrop(fp, td);
416 VFS_UNLOCK_GIANT(vfslocked);
417 }
418 return (error);
419 }
420
421 /*
422 * Given a file descriptor, set an ACL for it.
423 */
424 int
425 __acl_set_fd(struct thread *td, struct __acl_set_fd_args *uap)
426 {
427 struct file *fp;
428 int vfslocked, error;
429
430 error = getvnode(td->td_proc->p_fd, uap->filedes, &fp);
431 if (error == 0) {
432 vfslocked = VFS_LOCK_GIANT(fp->f_vnode->v_mount);
433 error = vacl_set_acl(td, fp->f_vnode, uap->type, uap->aclp);
434 fdrop(fp, td);
435 VFS_UNLOCK_GIANT(vfslocked);
436 }
437 return (error);
438 }
439
440 /*
441 * Given a file path, delete an ACL from it.
442 */
443 int
444 __acl_delete_file(struct thread *td, struct __acl_delete_file_args *uap)
445 {
446 struct nameidata nd;
447 int vfslocked, error;
448
449 NDINIT(&nd, LOOKUP, MPSAFE|FOLLOW, UIO_USERSPACE, uap->path, td);
450 error = namei(&nd);
451 vfslocked = NDHASGIANT(&nd);
452 if (error == 0) {
453 error = vacl_delete(td, nd.ni_vp, uap->type);
454 NDFREE(&nd, 0);
455 }
456 VFS_UNLOCK_GIANT(vfslocked);
457 return (error);
458 }
459
460 /*
461 * Given a file path, delete an ACL from it; don't follow links.
462 */
463 int
464 __acl_delete_link(struct thread *td, struct __acl_delete_link_args *uap)
465 {
466 struct nameidata nd;
467 int vfslocked, error;
468
469 NDINIT(&nd, LOOKUP, MPSAFE|NOFOLLOW, UIO_USERSPACE, uap->path, td);
470 error = namei(&nd);
471 vfslocked = NDHASGIANT(&nd);
472 if (error == 0) {
473 error = vacl_delete(td, nd.ni_vp, uap->type);
474 NDFREE(&nd, 0);
475 }
476 VFS_UNLOCK_GIANT(vfslocked);
477 return (error);
478 }
479
480 /*
481 * Given a file path, delete an ACL from it.
482 */
483 int
484 __acl_delete_fd(struct thread *td, struct __acl_delete_fd_args *uap)
485 {
486 struct file *fp;
487 int vfslocked, error;
488
489 error = getvnode(td->td_proc->p_fd, uap->filedes, &fp);
490 if (error == 0) {
491 vfslocked = VFS_LOCK_GIANT(fp->f_vnode->v_mount);
492 error = vacl_delete(td, fp->f_vnode, uap->type);
493 fdrop(fp, td);
494 VFS_UNLOCK_GIANT(vfslocked);
495 }
496 return (error);
497 }
498
499 /*
500 * Given a file path, check an ACL for it.
501 */
502 int
503 __acl_aclcheck_file(struct thread *td, struct __acl_aclcheck_file_args *uap)
504 {
505 struct nameidata nd;
506 int vfslocked, error;
507
508 NDINIT(&nd, LOOKUP, MPSAFE|FOLLOW, UIO_USERSPACE, uap->path, td);
509 error = namei(&nd);
510 vfslocked = NDHASGIANT(&nd);
511 if (error == 0) {
512 error = vacl_aclcheck(td, nd.ni_vp, uap->type, uap->aclp);
513 NDFREE(&nd, 0);
514 }
515 VFS_UNLOCK_GIANT(vfslocked);
516 return (error);
517 }
518
519 /*
520 * Given a file path, check an ACL for it; don't follow links.
521 */
522 int
523 __acl_aclcheck_link(struct thread *td, struct __acl_aclcheck_link_args *uap)
524 {
525 struct nameidata nd;
526 int vfslocked, error;
527
528 NDINIT(&nd, LOOKUP, MPSAFE|NOFOLLOW, UIO_USERSPACE, uap->path, td);
529 error = namei(&nd);
530 vfslocked = NDHASGIANT(&nd);
531 if (error == 0) {
532 error = vacl_aclcheck(td, nd.ni_vp, uap->type, uap->aclp);
533 NDFREE(&nd, 0);
534 }
535 VFS_UNLOCK_GIANT(vfslocked);
536 return (error);
537 }
538
539 /*
540 * Given a file descriptor, check an ACL for it.
541 */
542 int
543 __acl_aclcheck_fd(struct thread *td, struct __acl_aclcheck_fd_args *uap)
544 {
545 struct file *fp;
546 int vfslocked, error;
547
548 error = getvnode(td->td_proc->p_fd, uap->filedes, &fp);
549 if (error == 0) {
550 vfslocked = VFS_LOCK_GIANT(fp->f_vnode->v_mount);
551 error = vacl_aclcheck(td, fp->f_vnode, uap->type, uap->aclp);
552 fdrop(fp, td);
553 VFS_UNLOCK_GIANT(vfslocked);
554 }
555 return (error);
556 }
557
558 struct acl *
559 acl_alloc(int flags)
560 {
561 struct acl *aclp;
562
563 aclp = malloc(sizeof(*aclp), M_ACL, flags);
564 aclp->acl_maxcnt = ACL_MAX_ENTRIES;
565
566 return (aclp);
567 }
568
569 void
570 acl_free(struct acl *aclp)
571 {
572
573 free(aclp, M_ACL);
574 }
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