xref: /freebsd/sys/kern/subr_acl_nfs4.c (revision 10b9d77bf1ccf2f3affafa6261692cb92cf7e992)
1 /*-
2  * Copyright (c) 2008-2010 Edward Tomasz Napierała <trasz@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  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  */
26 
27 /*
28  * ACL support routines specific to NFSv4 access control lists.  These are
29  * utility routines for code common across file systems implementing NFSv4
30  * ACLs.
31  */
32 
33 #ifdef _KERNEL
34 #include <sys/cdefs.h>
35 __FBSDID("$FreeBSD$");
36 
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/mount.h>
40 #include <sys/priv.h>
41 #include <sys/vnode.h>
42 #include <sys/errno.h>
43 #include <sys/stat.h>
44 #include <sys/sysctl.h>
45 #include <sys/acl.h>
46 #else
47 #include <errno.h>
48 #include <assert.h>
49 #include <sys/acl.h>
50 #include <sys/stat.h>
51 #define KASSERT(a, b) assert(a)
52 #define CTASSERT(a)
53 
54 void		acl_nfs4_trivial_from_mode(struct acl *aclp, mode_t mode);
55 
56 #endif /* !_KERNEL */
57 
58 static int	acl_nfs4_old_semantics = 1;
59 
60 #ifdef _KERNEL
61 
62 SYSCTL_INT(_vfs, OID_AUTO, acl_nfs4_old_semantics, CTLFLAG_RW,
63     &acl_nfs4_old_semantics, 1, "Use pre-PSARC/2010/029 NFSv4 ACL semantics");
64 
65 static struct {
66 	accmode_t accmode;
67 	int mask;
68 } accmode2mask[] = {{VREAD, ACL_READ_DATA},
69 		    {VWRITE, ACL_WRITE_DATA},
70 		    {VAPPEND, ACL_APPEND_DATA},
71 		    {VEXEC, ACL_EXECUTE},
72 		    {VREAD_NAMED_ATTRS, ACL_READ_NAMED_ATTRS},
73 		    {VWRITE_NAMED_ATTRS, ACL_WRITE_NAMED_ATTRS},
74 		    {VDELETE_CHILD, ACL_DELETE_CHILD},
75 		    {VREAD_ATTRIBUTES, ACL_READ_ATTRIBUTES},
76 		    {VWRITE_ATTRIBUTES, ACL_WRITE_ATTRIBUTES},
77 		    {VDELETE, ACL_DELETE},
78 		    {VREAD_ACL, ACL_READ_ACL},
79 		    {VWRITE_ACL, ACL_WRITE_ACL},
80 		    {VWRITE_OWNER, ACL_WRITE_OWNER},
81 		    {VSYNCHRONIZE, ACL_SYNCHRONIZE},
82 		    {0, 0}};
83 
84 static int
85 _access_mask_from_accmode(accmode_t accmode)
86 {
87 	int access_mask = 0, i;
88 
89 	for (i = 0; accmode2mask[i].accmode != 0; i++) {
90 		if (accmode & accmode2mask[i].accmode)
91 			access_mask |= accmode2mask[i].mask;
92 	}
93 
94 	/*
95 	 * VAPPEND is just a modifier for VWRITE; if the caller asked
96 	 * for 'VAPPEND | VWRITE', we want to check for ACL_APPEND_DATA only.
97 	 */
98 	if (access_mask & ACL_APPEND_DATA)
99 		access_mask &= ~ACL_WRITE_DATA;
100 
101 	return (access_mask);
102 }
103 
104 /*
105  * Return 0, iff access is allowed, 1 otherwise.
106  */
107 static int
108 _acl_denies(const struct acl *aclp, int access_mask, struct ucred *cred,
109     int file_uid, int file_gid, int *denied_explicitly)
110 {
111 	int i;
112 	const struct acl_entry *entry;
113 
114 	if (denied_explicitly != NULL)
115 		*denied_explicitly = 0;
116 
117 	KASSERT(aclp->acl_cnt > 0, ("aclp->acl_cnt > 0"));
118 	KASSERT(aclp->acl_cnt <= ACL_MAX_ENTRIES,
119 	    ("aclp->acl_cnt <= ACL_MAX_ENTRIES"));
120 
121 	for (i = 0; i < aclp->acl_cnt; i++) {
122 		entry = &(aclp->acl_entry[i]);
123 
124 		if (entry->ae_entry_type != ACL_ENTRY_TYPE_ALLOW &&
125 		    entry->ae_entry_type != ACL_ENTRY_TYPE_DENY)
126 			continue;
127 		if (entry->ae_flags & ACL_ENTRY_INHERIT_ONLY)
128 			continue;
129 		switch (entry->ae_tag) {
130 		case ACL_USER_OBJ:
131 			if (file_uid != cred->cr_uid)
132 				continue;
133 			break;
134 		case ACL_USER:
135 			if (entry->ae_id != cred->cr_uid)
136 				continue;
137 			break;
138 		case ACL_GROUP_OBJ:
139 			if (!groupmember(file_gid, cred))
140 				continue;
141 			break;
142 		case ACL_GROUP:
143 			if (!groupmember(entry->ae_id, cred))
144 				continue;
145 			break;
146 		default:
147 			KASSERT(entry->ae_tag == ACL_EVERYONE,
148 			    ("entry->ae_tag == ACL_EVERYONE"));
149 		}
150 
151 		if (entry->ae_entry_type == ACL_ENTRY_TYPE_DENY) {
152 			if (entry->ae_perm & access_mask) {
153 				if (denied_explicitly != NULL)
154 					*denied_explicitly = 1;
155 				return (1);
156 			}
157 		}
158 
159 		access_mask &= ~(entry->ae_perm);
160 		if (access_mask == 0)
161 			return (0);
162 	}
163 
164 	return (1);
165 }
166 
167 int
168 vaccess_acl_nfs4(enum vtype type, uid_t file_uid, gid_t file_gid,
169     struct acl *aclp, accmode_t accmode, struct ucred *cred, int *privused)
170 {
171 	accmode_t priv_granted = 0;
172 	int denied, explicitly_denied, access_mask, is_directory,
173 	    must_be_owner = 0;
174 	mode_t file_mode = 0;
175 
176 	KASSERT((accmode & ~(VEXEC | VWRITE | VREAD | VADMIN | VAPPEND |
177 	    VEXPLICIT_DENY | VREAD_NAMED_ATTRS | VWRITE_NAMED_ATTRS |
178 	    VDELETE_CHILD | VREAD_ATTRIBUTES | VWRITE_ATTRIBUTES | VDELETE |
179 	    VREAD_ACL | VWRITE_ACL | VWRITE_OWNER | VSYNCHRONIZE)) == 0,
180 	    ("invalid bit in accmode"));
181 	KASSERT((accmode & VAPPEND) == 0 || (accmode & VWRITE),
182 	    	("VAPPEND without VWRITE"));
183 
184 	if (privused != NULL)
185 		*privused = 0;
186 
187 	if (accmode & VADMIN)
188 		must_be_owner = 1;
189 
190 	/*
191 	 * Ignore VSYNCHRONIZE permission.
192 	 */
193 	accmode &= ~VSYNCHRONIZE;
194 
195 	access_mask = _access_mask_from_accmode(accmode);
196 
197 	if (type == VDIR)
198 		is_directory = 1;
199 	else
200 		is_directory = 0;
201 
202 	/*
203 	 * File owner is always allowed to read and write the ACL
204 	 * and basic attributes.  This is to prevent a situation
205 	 * where user would change ACL in a way that prevents him
206 	 * from undoing the change.
207 	 */
208 	if (file_uid == cred->cr_uid)
209 		access_mask &= ~(ACL_READ_ACL | ACL_WRITE_ACL |
210 		    ACL_READ_ATTRIBUTES | ACL_WRITE_ATTRIBUTES);
211 
212 	/*
213 	 * Ignore append permission for regular files; use write
214 	 * permission instead.
215 	 */
216 	if (!is_directory && (access_mask & ACL_APPEND_DATA)) {
217 		access_mask &= ~ACL_APPEND_DATA;
218 		access_mask |= ACL_WRITE_DATA;
219 	}
220 
221 	denied = _acl_denies(aclp, access_mask, cred, file_uid, file_gid,
222 	    &explicitly_denied);
223 
224 	if (must_be_owner) {
225 		if (file_uid != cred->cr_uid)
226 			denied = EPERM;
227 	}
228 
229 	/*
230 	 * For VEXEC, ensure that at least one execute bit is set for
231 	 * non-directories. We have to check the mode here to stay
232 	 * consistent with execve(2). See the test in
233 	 * exec_check_permissions().
234 	 */
235 	acl_nfs4_sync_mode_from_acl(&file_mode, aclp);
236 	if (!denied && !is_directory && (accmode & VEXEC) &&
237 	    (file_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) == 0)
238 		denied = EACCES;
239 
240 	if (!denied)
241 		return (0);
242 
243 	/*
244 	 * Access failed.  Iff it was not denied explicitly and
245 	 * VEXPLICIT_DENY flag was specified, allow access.
246 	 */
247 	if ((accmode & VEXPLICIT_DENY) && explicitly_denied == 0)
248 		return (0);
249 
250 	accmode &= ~VEXPLICIT_DENY;
251 
252 	/*
253 	 * No match.  Try to use privileges, if there are any.
254 	 */
255 	if (is_directory) {
256 		if ((accmode & VEXEC) && !priv_check_cred(cred,
257 		    PRIV_VFS_LOOKUP, 0))
258 			priv_granted |= VEXEC;
259 	} else {
260 		/*
261 		 * Ensure that at least one execute bit is on. Otherwise,
262 		 * a privileged user will always succeed, and we don't want
263 		 * this to happen unless the file really is executable.
264 		 */
265 		if ((accmode & VEXEC) && (file_mode &
266 		    (S_IXUSR | S_IXGRP | S_IXOTH)) != 0 &&
267 		    !priv_check_cred(cred, PRIV_VFS_EXEC, 0))
268 			priv_granted |= VEXEC;
269 	}
270 
271 	if ((accmode & VREAD) && !priv_check_cred(cred, PRIV_VFS_READ, 0))
272 		priv_granted |= VREAD;
273 
274 	if ((accmode & (VWRITE | VAPPEND | VDELETE_CHILD)) &&
275 	    !priv_check_cred(cred, PRIV_VFS_WRITE, 0))
276 		priv_granted |= (VWRITE | VAPPEND | VDELETE_CHILD);
277 
278 	if ((accmode & VADMIN_PERMS) &&
279 	    !priv_check_cred(cred, PRIV_VFS_ADMIN, 0))
280 		priv_granted |= VADMIN_PERMS;
281 
282 	if ((accmode & VSTAT_PERMS) &&
283 	    !priv_check_cred(cred, PRIV_VFS_STAT, 0))
284 		priv_granted |= VSTAT_PERMS;
285 
286 	if ((accmode & priv_granted) == accmode) {
287 		if (privused != NULL)
288 			*privused = 1;
289 
290 		return (0);
291 	}
292 
293 	if (accmode & (VADMIN_PERMS | VDELETE_CHILD | VDELETE))
294 		denied = EPERM;
295 	else
296 		denied = EACCES;
297 
298 	return (denied);
299 }
300 #endif /* _KERNEL */
301 
302 static int
303 _acl_entry_matches(struct acl_entry *entry, acl_tag_t tag, acl_perm_t perm,
304     acl_entry_type_t entry_type)
305 {
306 	if (entry->ae_tag != tag)
307 		return (0);
308 
309 	if (entry->ae_id != ACL_UNDEFINED_ID)
310 		return (0);
311 
312 	if (entry->ae_perm != perm)
313 		return (0);
314 
315 	if (entry->ae_entry_type != entry_type)
316 		return (0);
317 
318 	if (entry->ae_flags != 0)
319 		return (0);
320 
321 	return (1);
322 }
323 
324 static struct acl_entry *
325 _acl_append(struct acl *aclp, acl_tag_t tag, acl_perm_t perm,
326     acl_entry_type_t entry_type)
327 {
328 	struct acl_entry *entry;
329 
330 	KASSERT(aclp->acl_cnt + 1 <= ACL_MAX_ENTRIES,
331 	    ("aclp->acl_cnt + 1 <= ACL_MAX_ENTRIES"));
332 
333 	entry = &(aclp->acl_entry[aclp->acl_cnt]);
334 	aclp->acl_cnt++;
335 
336 	entry->ae_tag = tag;
337 	entry->ae_id = ACL_UNDEFINED_ID;
338 	entry->ae_perm = perm;
339 	entry->ae_entry_type = entry_type;
340 	entry->ae_flags = 0;
341 
342 	return (entry);
343 }
344 
345 static struct acl_entry *
346 _acl_duplicate_entry(struct acl *aclp, int entry_index)
347 {
348 	int i;
349 
350 	KASSERT(aclp->acl_cnt + 1 <= ACL_MAX_ENTRIES,
351 	    ("aclp->acl_cnt + 1 <= ACL_MAX_ENTRIES"));
352 
353 	for (i = aclp->acl_cnt; i > entry_index; i--)
354 		aclp->acl_entry[i] = aclp->acl_entry[i - 1];
355 
356 	aclp->acl_cnt++;
357 
358 	return (&(aclp->acl_entry[entry_index + 1]));
359 }
360 
361 static void
362 acl_nfs4_sync_acl_from_mode_draft(struct acl *aclp, mode_t mode,
363     int file_owner_id)
364 {
365 	int i, meets, must_append;
366 	struct acl_entry *entry, *copy, *previous,
367 	    *a1, *a2, *a3, *a4, *a5, *a6;
368 	mode_t amode;
369 	const int READ = 04;
370 	const int WRITE = 02;
371 	const int EXEC = 01;
372 
373 	KASSERT(aclp->acl_cnt <= ACL_MAX_ENTRIES,
374 	    ("aclp->acl_cnt <= ACL_MAX_ENTRIES"));
375 
376 	/*
377 	 * NFSv4 Minor Version 1, draft-ietf-nfsv4-minorversion1-03.txt
378 	 *
379 	 * 3.16.6.3. Applying a Mode to an Existing ACL
380 	 */
381 
382 	/*
383 	 * 1. For each ACE:
384 	 */
385 	for (i = 0; i < aclp->acl_cnt; i++) {
386 		entry = &(aclp->acl_entry[i]);
387 
388 		/*
389 		 * 1.1. If the type is neither ALLOW or DENY - skip.
390 		 */
391 		if (entry->ae_entry_type != ACL_ENTRY_TYPE_ALLOW &&
392 		    entry->ae_entry_type != ACL_ENTRY_TYPE_DENY)
393 			continue;
394 
395 		/*
396 		 * 1.2. If ACL_ENTRY_INHERIT_ONLY is set - skip.
397 		 */
398 		if (entry->ae_flags & ACL_ENTRY_INHERIT_ONLY)
399 			continue;
400 
401 		/*
402 		 * 1.3. If ACL_ENTRY_FILE_INHERIT or ACL_ENTRY_DIRECTORY_INHERIT
403 		 *      are set:
404 		 */
405 		if (entry->ae_flags &
406 		    (ACL_ENTRY_FILE_INHERIT | ACL_ENTRY_DIRECTORY_INHERIT)) {
407 			/*
408 			 * 1.3.1. A copy of the current ACE is made, and placed
409 			 *        in the ACL immediately following the current
410 			 *        ACE.
411 			 */
412 			copy = _acl_duplicate_entry(aclp, i);
413 
414 			/*
415 			 * 1.3.2. In the first ACE, the flag
416 			 *        ACL_ENTRY_INHERIT_ONLY is set.
417 			 */
418 			entry->ae_flags |= ACL_ENTRY_INHERIT_ONLY;
419 
420 			/*
421 			 * 1.3.3. In the second ACE, the following flags
422 			 *        are cleared:
423 			 *        ACL_ENTRY_FILE_INHERIT,
424 			 *        ACL_ENTRY_DIRECTORY_INHERIT,
425 			 *        ACL_ENTRY_NO_PROPAGATE_INHERIT.
426 			 */
427 			copy->ae_flags &= ~(ACL_ENTRY_FILE_INHERIT |
428 			    ACL_ENTRY_DIRECTORY_INHERIT |
429 			    ACL_ENTRY_NO_PROPAGATE_INHERIT);
430 
431 			/*
432 			 * The algorithm continues on with the second ACE.
433 			 */
434 			i++;
435 			entry = copy;
436 		}
437 
438 		/*
439 		 * 1.4. If it's owner@, group@ or everyone@ entry, clear
440 		 *      ACL_READ_DATA, ACL_WRITE_DATA, ACL_APPEND_DATA
441 		 *      and ACL_EXECUTE.  Continue to the next entry.
442 		 */
443 		if (entry->ae_tag == ACL_USER_OBJ ||
444 		    entry->ae_tag == ACL_GROUP_OBJ ||
445 		    entry->ae_tag == ACL_EVERYONE) {
446 			entry->ae_perm &= ~(ACL_READ_DATA | ACL_WRITE_DATA |
447 			    ACL_APPEND_DATA | ACL_EXECUTE);
448 			continue;
449 		}
450 
451 		/*
452 		 * 1.5. Otherwise, if the "who" field did not match one
453 		 *      of OWNER@, GROUP@, EVERYONE@:
454 		 *
455 		 * 1.5.1. If the type is ALLOW, check the preceding ACE.
456 		 *        If it does not meet all of the following criteria:
457 		 */
458 		if (entry->ae_entry_type != ACL_ENTRY_TYPE_ALLOW)
459 			continue;
460 
461 		meets = 0;
462 		if (i > 0) {
463 			meets = 1;
464 			previous = &(aclp->acl_entry[i - 1]);
465 
466 			/*
467 			 * 1.5.1.1. The type field is DENY,
468 			 */
469 			if (previous->ae_entry_type != ACL_ENTRY_TYPE_DENY)
470 				meets = 0;
471 
472 			/*
473 			 * 1.5.1.2. The "who" field is the same as the current
474 			 *          ACE,
475 			 *
476 			 * 1.5.1.3. The flag bit ACE4_IDENTIFIER_GROUP
477 			 *          is the same as it is in the current ACE,
478 			 *          and no other flag bits are set,
479 			 */
480 			if (previous->ae_id != entry->ae_id ||
481 			    previous->ae_tag != entry->ae_tag)
482 				meets = 0;
483 
484 			if (previous->ae_flags)
485 				meets = 0;
486 
487 			/*
488 			 * 1.5.1.4. The mask bits are a subset of the mask bits
489 			 *          of the current ACE, and are also subset of
490 			 *          the following: ACL_READ_DATA,
491 			 *          ACL_WRITE_DATA, ACL_APPEND_DATA, ACL_EXECUTE
492 			 */
493 			if (previous->ae_perm & ~(entry->ae_perm))
494 				meets = 0;
495 
496 			if (previous->ae_perm & ~(ACL_READ_DATA |
497 			    ACL_WRITE_DATA | ACL_APPEND_DATA | ACL_EXECUTE))
498 				meets = 0;
499 		}
500 
501 		if (!meets) {
502 			/*
503 		 	 * Then the ACE of type DENY, with a who equal
504 			 * to the current ACE, flag bits equal to
505 			 * (<current ACE flags> & <ACE_IDENTIFIER_GROUP>)
506 			 * and no mask bits, is prepended.
507 			 */
508 			previous = entry;
509 			entry = _acl_duplicate_entry(aclp, i);
510 
511 			/* Adjust counter, as we've just added an entry. */
512 			i++;
513 
514 			previous->ae_tag = entry->ae_tag;
515 			previous->ae_id = entry->ae_id;
516 			previous->ae_flags = entry->ae_flags;
517 			previous->ae_perm = 0;
518 			previous->ae_entry_type = ACL_ENTRY_TYPE_DENY;
519 		}
520 
521 		/*
522 		 * 1.5.2. The following modifications are made to the prepended
523 		 *        ACE.  The intent is to mask the following ACE
524 		 *        to disallow ACL_READ_DATA, ACL_WRITE_DATA,
525 		 *        ACL_APPEND_DATA, or ACL_EXECUTE, based upon the group
526 		 *        permissions of the new mode.  As a special case,
527 		 *        if the ACE matches the current owner of the file,
528 		 *        the owner bits are used, rather than the group bits.
529 		 *        This is reflected in the algorithm below.
530 		 */
531 		amode = mode >> 3;
532 
533 		/*
534 		 * If ACE4_IDENTIFIER_GROUP is not set, and the "who" field
535 		 * in ACE matches the owner of the file, we shift amode three
536 		 * more bits, in order to have the owner permission bits
537 		 * placed in the three low order bits of amode.
538 		 */
539 		if (entry->ae_tag == ACL_USER && entry->ae_id == file_owner_id)
540 			amode = amode >> 3;
541 
542 		if (entry->ae_perm & ACL_READ_DATA) {
543 			if (amode & READ)
544 				previous->ae_perm &= ~ACL_READ_DATA;
545 			else
546 				previous->ae_perm |= ACL_READ_DATA;
547 		}
548 
549 		if (entry->ae_perm & ACL_WRITE_DATA) {
550 			if (amode & WRITE)
551 				previous->ae_perm &= ~ACL_WRITE_DATA;
552 			else
553 				previous->ae_perm |= ACL_WRITE_DATA;
554 		}
555 
556 		if (entry->ae_perm & ACL_APPEND_DATA) {
557 			if (amode & WRITE)
558 				previous->ae_perm &= ~ACL_APPEND_DATA;
559 			else
560 				previous->ae_perm |= ACL_APPEND_DATA;
561 		}
562 
563 		if (entry->ae_perm & ACL_EXECUTE) {
564 			if (amode & EXEC)
565 				previous->ae_perm &= ~ACL_EXECUTE;
566 			else
567 				previous->ae_perm |= ACL_EXECUTE;
568 		}
569 
570 		/*
571 		 * 1.5.3. If ACE4_IDENTIFIER_GROUP is set in the flags
572 		 *        of the ALLOW ace:
573 		 *
574 		 * XXX: This point is not there in the Falkner's draft.
575 		 */
576 		if (entry->ae_tag == ACL_GROUP &&
577 		    entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW) {
578 			mode_t extramode, ownermode;
579 			extramode = (mode >> 3) & 07;
580 			ownermode = mode >> 6;
581 			extramode &= ~ownermode;
582 
583 			if (extramode) {
584 				if (extramode & READ) {
585 					entry->ae_perm &= ~ACL_READ_DATA;
586 					previous->ae_perm &= ~ACL_READ_DATA;
587 				}
588 
589 				if (extramode & WRITE) {
590 					entry->ae_perm &=
591 					    ~(ACL_WRITE_DATA | ACL_APPEND_DATA);
592 					previous->ae_perm &=
593 					    ~(ACL_WRITE_DATA | ACL_APPEND_DATA);
594 				}
595 
596 				if (extramode & EXEC) {
597 					entry->ae_perm &= ~ACL_EXECUTE;
598 					previous->ae_perm &= ~ACL_EXECUTE;
599 				}
600 			}
601 		}
602 	}
603 
604 	/*
605 	 * 2. If there at least six ACEs, the final six ACEs are examined.
606 	 *    If they are not equal to what we want, append six ACEs.
607 	 */
608 	must_append = 0;
609 	if (aclp->acl_cnt < 6) {
610 		must_append = 1;
611 	} else {
612 		a6 = &(aclp->acl_entry[aclp->acl_cnt - 1]);
613 		a5 = &(aclp->acl_entry[aclp->acl_cnt - 2]);
614 		a4 = &(aclp->acl_entry[aclp->acl_cnt - 3]);
615 		a3 = &(aclp->acl_entry[aclp->acl_cnt - 4]);
616 		a2 = &(aclp->acl_entry[aclp->acl_cnt - 5]);
617 		a1 = &(aclp->acl_entry[aclp->acl_cnt - 6]);
618 
619 		if (!_acl_entry_matches(a1, ACL_USER_OBJ, 0,
620 		    ACL_ENTRY_TYPE_DENY))
621 			must_append = 1;
622 		if (!_acl_entry_matches(a2, ACL_USER_OBJ, ACL_WRITE_ACL |
623 		    ACL_WRITE_OWNER | ACL_WRITE_ATTRIBUTES |
624 		    ACL_WRITE_NAMED_ATTRS, ACL_ENTRY_TYPE_ALLOW))
625 			must_append = 1;
626 		if (!_acl_entry_matches(a3, ACL_GROUP_OBJ, 0,
627 		    ACL_ENTRY_TYPE_DENY))
628 			must_append = 1;
629 		if (!_acl_entry_matches(a4, ACL_GROUP_OBJ, 0,
630 		    ACL_ENTRY_TYPE_ALLOW))
631 			must_append = 1;
632 		if (!_acl_entry_matches(a5, ACL_EVERYONE, ACL_WRITE_ACL |
633 		    ACL_WRITE_OWNER | ACL_WRITE_ATTRIBUTES |
634 		    ACL_WRITE_NAMED_ATTRS, ACL_ENTRY_TYPE_DENY))
635 			must_append = 1;
636 		if (!_acl_entry_matches(a6, ACL_EVERYONE, ACL_READ_ACL |
637 		    ACL_READ_ATTRIBUTES | ACL_READ_NAMED_ATTRS |
638 		    ACL_SYNCHRONIZE, ACL_ENTRY_TYPE_ALLOW))
639 			must_append = 1;
640 	}
641 
642 	if (must_append) {
643 		KASSERT(aclp->acl_cnt + 6 <= ACL_MAX_ENTRIES,
644 		    ("aclp->acl_cnt <= ACL_MAX_ENTRIES"));
645 
646 		a1 = _acl_append(aclp, ACL_USER_OBJ, 0, ACL_ENTRY_TYPE_DENY);
647 		a2 = _acl_append(aclp, ACL_USER_OBJ, ACL_WRITE_ACL |
648 		    ACL_WRITE_OWNER | ACL_WRITE_ATTRIBUTES |
649 		    ACL_WRITE_NAMED_ATTRS, ACL_ENTRY_TYPE_ALLOW);
650 		a3 = _acl_append(aclp, ACL_GROUP_OBJ, 0, ACL_ENTRY_TYPE_DENY);
651 		a4 = _acl_append(aclp, ACL_GROUP_OBJ, 0, ACL_ENTRY_TYPE_ALLOW);
652 		a5 = _acl_append(aclp, ACL_EVERYONE, ACL_WRITE_ACL |
653 		    ACL_WRITE_OWNER | ACL_WRITE_ATTRIBUTES |
654 		    ACL_WRITE_NAMED_ATTRS, ACL_ENTRY_TYPE_DENY);
655 		a6 = _acl_append(aclp, ACL_EVERYONE, ACL_READ_ACL |
656 		    ACL_READ_ATTRIBUTES | ACL_READ_NAMED_ATTRS |
657 		    ACL_SYNCHRONIZE, ACL_ENTRY_TYPE_ALLOW);
658 
659 		KASSERT(a1 != NULL && a2 != NULL && a3 != NULL && a4 != NULL &&
660 		    a5 != NULL && a6 != NULL, ("couldn't append to ACL."));
661 	}
662 
663 	/*
664 	 * 3. The final six ACEs are adjusted according to the incoming mode.
665 	 */
666 	if (mode & S_IRUSR)
667 		a2->ae_perm |= ACL_READ_DATA;
668 	else
669 		a1->ae_perm |= ACL_READ_DATA;
670 	if (mode & S_IWUSR)
671 		a2->ae_perm |= (ACL_WRITE_DATA | ACL_APPEND_DATA);
672 	else
673 		a1->ae_perm |= (ACL_WRITE_DATA | ACL_APPEND_DATA);
674 	if (mode & S_IXUSR)
675 		a2->ae_perm |= ACL_EXECUTE;
676 	else
677 		a1->ae_perm |= ACL_EXECUTE;
678 
679 	if (mode & S_IRGRP)
680 		a4->ae_perm |= ACL_READ_DATA;
681 	else
682 		a3->ae_perm |= ACL_READ_DATA;
683 	if (mode & S_IWGRP)
684 		a4->ae_perm |= (ACL_WRITE_DATA | ACL_APPEND_DATA);
685 	else
686 		a3->ae_perm |= (ACL_WRITE_DATA | ACL_APPEND_DATA);
687 	if (mode & S_IXGRP)
688 		a4->ae_perm |= ACL_EXECUTE;
689 	else
690 		a3->ae_perm |= ACL_EXECUTE;
691 
692 	if (mode & S_IROTH)
693 		a6->ae_perm |= ACL_READ_DATA;
694 	else
695 		a5->ae_perm |= ACL_READ_DATA;
696 	if (mode & S_IWOTH)
697 		a6->ae_perm |= (ACL_WRITE_DATA | ACL_APPEND_DATA);
698 	else
699 		a5->ae_perm |= (ACL_WRITE_DATA | ACL_APPEND_DATA);
700 	if (mode & S_IXOTH)
701 		a6->ae_perm |= ACL_EXECUTE;
702 	else
703 		a5->ae_perm |= ACL_EXECUTE;
704 }
705 
706 void
707 acl_nfs4_sync_acl_from_mode(struct acl *aclp, mode_t mode,
708     int file_owner_id)
709 {
710 
711 	if (acl_nfs4_old_semantics)
712 		acl_nfs4_sync_acl_from_mode_draft(aclp, mode, file_owner_id);
713 	else
714 		acl_nfs4_trivial_from_mode(aclp, mode);
715 }
716 
717 void
718 acl_nfs4_sync_mode_from_acl(mode_t *_mode, const struct acl *aclp)
719 {
720 	int i;
721 	mode_t old_mode = *_mode, mode = 0, seen = 0;
722 	const struct acl_entry *entry;
723 
724 	KASSERT(aclp->acl_cnt > 0, ("aclp->acl_cnt > 0"));
725 	KASSERT(aclp->acl_cnt <= ACL_MAX_ENTRIES,
726 	    ("aclp->acl_cnt <= ACL_MAX_ENTRIES"));
727 
728 	/*
729 	 * NFSv4 Minor Version 1, draft-ietf-nfsv4-minorversion1-03.txt
730 	 *
731 	 * 3.16.6.1. Recomputing mode upon SETATTR of ACL
732 	 */
733 
734 	for (i = 0; i < aclp->acl_cnt; i++) {
735 		entry = &(aclp->acl_entry[i]);
736 
737 		if (entry->ae_entry_type != ACL_ENTRY_TYPE_ALLOW &&
738 		    entry->ae_entry_type != ACL_ENTRY_TYPE_DENY)
739 			continue;
740 
741 		if (entry->ae_flags & ACL_ENTRY_INHERIT_ONLY)
742 			continue;
743 
744 		if (entry->ae_tag == ACL_USER_OBJ) {
745 			if ((entry->ae_perm & ACL_READ_DATA) &&
746 			    ((seen & S_IRUSR) == 0)) {
747 				seen |= S_IRUSR;
748 				if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
749 					mode |= S_IRUSR;
750 			}
751 			if ((entry->ae_perm & ACL_WRITE_DATA) &&
752 			     ((seen & S_IWUSR) == 0)) {
753 				seen |= S_IWUSR;
754 				if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
755 					mode |= S_IWUSR;
756 			}
757 			if ((entry->ae_perm & ACL_EXECUTE) &&
758 			    ((seen & S_IXUSR) == 0)) {
759 				seen |= S_IXUSR;
760 				if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
761 					mode |= S_IXUSR;
762 			}
763 		} else if (entry->ae_tag == ACL_GROUP_OBJ) {
764 			if ((entry->ae_perm & ACL_READ_DATA) &&
765 			    ((seen & S_IRGRP) == 0)) {
766 				seen |= S_IRGRP;
767 				if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
768 					mode |= S_IRGRP;
769 			}
770 			if ((entry->ae_perm & ACL_WRITE_DATA) &&
771 			    ((seen & S_IWGRP) == 0)) {
772 				seen |= S_IWGRP;
773 				if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
774 					mode |= S_IWGRP;
775 			}
776 			if ((entry->ae_perm & ACL_EXECUTE) &&
777 			    ((seen & S_IXGRP) == 0)) {
778 				seen |= S_IXGRP;
779 				if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
780 					mode |= S_IXGRP;
781 			}
782 		} else if (entry->ae_tag == ACL_EVERYONE) {
783 			if (entry->ae_perm & ACL_READ_DATA) {
784 				if ((seen & S_IRUSR) == 0) {
785 					seen |= S_IRUSR;
786 					if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
787 						mode |= S_IRUSR;
788 				}
789 				if ((seen & S_IRGRP) == 0) {
790 					seen |= S_IRGRP;
791 					if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
792 						mode |= S_IRGRP;
793 				}
794 				if ((seen & S_IROTH) == 0) {
795 					seen |= S_IROTH;
796 					if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
797 						mode |= S_IROTH;
798 				}
799 			}
800 			if (entry->ae_perm & ACL_WRITE_DATA) {
801 				if ((seen & S_IWUSR) == 0) {
802 					seen |= S_IWUSR;
803 					if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
804 						mode |= S_IWUSR;
805 				}
806 				if ((seen & S_IWGRP) == 0) {
807 					seen |= S_IWGRP;
808 					if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
809 						mode |= S_IWGRP;
810 				}
811 				if ((seen & S_IWOTH) == 0) {
812 					seen |= S_IWOTH;
813 					if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
814 						mode |= S_IWOTH;
815 				}
816 			}
817 			if (entry->ae_perm & ACL_EXECUTE) {
818 				if ((seen & S_IXUSR) == 0) {
819 					seen |= S_IXUSR;
820 					if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
821 						mode |= S_IXUSR;
822 				}
823 				if ((seen & S_IXGRP) == 0) {
824 					seen |= S_IXGRP;
825 					if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
826 						mode |= S_IXGRP;
827 				}
828 				if ((seen & S_IXOTH) == 0) {
829 					seen |= S_IXOTH;
830 					if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
831 						mode |= S_IXOTH;
832 				}
833 			}
834 		}
835 	}
836 
837 	*_mode = mode | (old_mode & ACL_PRESERVE_MASK);
838 }
839 
840 /*
841  * Calculate inherited ACL in a manner compatible with NFSv4 Minor Version 1,
842  * draft-ietf-nfsv4-minorversion1-03.txt.
843  */
844 static void
845 acl_nfs4_compute_inherited_acl_draft(const struct acl *parent_aclp,
846     struct acl *child_aclp, mode_t mode, int file_owner_id,
847     int is_directory)
848 {
849 	int i, flags;
850 	const struct acl_entry *parent_entry;
851 	struct acl_entry *entry, *copy;
852 
853 	KASSERT(child_aclp->acl_cnt == 0, ("child_aclp->acl_cnt == 0"));
854 	KASSERT(parent_aclp->acl_cnt > 0, ("parent_aclp->acl_cnt > 0"));
855 	KASSERT(parent_aclp->acl_cnt <= ACL_MAX_ENTRIES,
856 	    ("parent_aclp->acl_cnt <= ACL_MAX_ENTRIES"));
857 
858 	/*
859 	 * NFSv4 Minor Version 1, draft-ietf-nfsv4-minorversion1-03.txt
860 	 *
861 	 * 3.16.6.2. Applying the mode given to CREATE or OPEN
862 	 *           to an inherited ACL
863 	 */
864 
865 	/*
866 	 * 1. Form an ACL that is the concatenation of all inheritable ACEs.
867 	 */
868 	for (i = 0; i < parent_aclp->acl_cnt; i++) {
869 		parent_entry = &(parent_aclp->acl_entry[i]);
870 		flags = parent_entry->ae_flags;
871 
872 		/*
873 		 * Entry is not inheritable at all.
874 		 */
875 		if ((flags & (ACL_ENTRY_DIRECTORY_INHERIT |
876 		    ACL_ENTRY_FILE_INHERIT)) == 0)
877 			continue;
878 
879 		/*
880 		 * We're creating a file, but entry is not inheritable
881 		 * by files.
882 		 */
883 		if (!is_directory && (flags & ACL_ENTRY_FILE_INHERIT) == 0)
884 			continue;
885 
886 		/*
887 		 * Entry is inheritable only by files, but has NO_PROPAGATE
888 		 * flag set, and we're creating a directory, so it wouldn't
889 		 * propagate to any file in that directory anyway.
890 		 */
891 		if (is_directory &&
892 		    (flags & ACL_ENTRY_DIRECTORY_INHERIT) == 0 &&
893 		    (flags & ACL_ENTRY_NO_PROPAGATE_INHERIT))
894 			continue;
895 
896 		KASSERT(child_aclp->acl_cnt + 1 <= ACL_MAX_ENTRIES,
897 		    ("child_aclp->acl_cnt + 1 <= ACL_MAX_ENTRIES"));
898 		child_aclp->acl_entry[child_aclp->acl_cnt] = *parent_entry;
899 		child_aclp->acl_cnt++;
900 	}
901 
902 	/*
903 	 * 2. For each entry in the new ACL, adjust its flags, possibly
904 	 *    creating two entries in place of one.
905 	 */
906 	for (i = 0; i < child_aclp->acl_cnt; i++) {
907 		entry = &(child_aclp->acl_entry[i]);
908 
909 		/*
910 		 * This is not in the specification, but SunOS
911 		 * apparently does that.
912 		 */
913 		if (((entry->ae_flags & ACL_ENTRY_NO_PROPAGATE_INHERIT) ||
914 		    !is_directory) &&
915 		    entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
916 			entry->ae_perm &= ~(ACL_WRITE_ACL | ACL_WRITE_OWNER);
917 
918 		/*
919 		 * 2.A. If the ACL_ENTRY_NO_PROPAGATE_INHERIT is set, or if the object
920 		 *      being created is not a directory, then clear the
921 		 *      following flags: ACL_ENTRY_NO_PROPAGATE_INHERIT,
922 		 *      ACL_ENTRY_FILE_INHERIT, ACL_ENTRY_DIRECTORY_INHERIT,
923 		 *      ACL_ENTRY_INHERIT_ONLY.
924 		 */
925 		if (entry->ae_flags & ACL_ENTRY_NO_PROPAGATE_INHERIT ||
926 		    !is_directory) {
927 			entry->ae_flags &= ~(ACL_ENTRY_NO_PROPAGATE_INHERIT |
928 			ACL_ENTRY_FILE_INHERIT | ACL_ENTRY_DIRECTORY_INHERIT |
929 			ACL_ENTRY_INHERIT_ONLY);
930 
931 			/*
932 			 * Continue on to the next ACE.
933 			 */
934 			continue;
935 		}
936 
937 		/*
938 		 * 2.B. If the object is a directory and ACL_ENTRY_FILE_INHERIT
939 		 *      is set, but ACL_ENTRY_NO_PROPAGATE_INHERIT is not set, ensure
940 		 *      that ACL_ENTRY_INHERIT_ONLY is set.  Continue to the
941 		 *      next ACE.  Otherwise...
942 		 */
943 		/*
944 		 * XXX: Read it again and make sure what does the "otherwise"
945 		 *      apply to.
946 		 */
947 		if (is_directory &&
948 		    (entry->ae_flags & ACL_ENTRY_FILE_INHERIT) &&
949 		    ((entry->ae_flags & ACL_ENTRY_DIRECTORY_INHERIT) == 0)) {
950 			entry->ae_flags |= ACL_ENTRY_INHERIT_ONLY;
951 			continue;
952 		}
953 
954 		/*
955 		 * 2.C. If the type of the ACE is neither ALLOW nor deny,
956 		 *      then continue.
957 		 */
958 		if (entry->ae_entry_type != ACL_ENTRY_TYPE_ALLOW &&
959 		    entry->ae_entry_type != ACL_ENTRY_TYPE_DENY)
960 			continue;
961 
962 		/*
963 		 * 2.D. Copy the original ACE into a second, adjacent ACE.
964 		 */
965 		copy = _acl_duplicate_entry(child_aclp, i);
966 
967 		/*
968 		 * 2.E. On the first ACE, ensure that ACL_ENTRY_INHERIT_ONLY
969 		 *      is set.
970 		 */
971 		entry->ae_flags |= ACL_ENTRY_INHERIT_ONLY;
972 
973 		/*
974 		 * 2.F. On the second ACE, clear the following flags:
975 		 *      ACL_ENTRY_NO_PROPAGATE_INHERIT, ACL_ENTRY_FILE_INHERIT,
976 		 *      ACL_ENTRY_DIRECTORY_INHERIT, ACL_ENTRY_INHERIT_ONLY.
977 		 */
978 		copy->ae_flags &= ~(ACL_ENTRY_NO_PROPAGATE_INHERIT |
979 		    ACL_ENTRY_FILE_INHERIT | ACL_ENTRY_DIRECTORY_INHERIT |
980 		    ACL_ENTRY_INHERIT_ONLY);
981 
982 		/*
983 		 * 2.G. On the second ACE, if the type is ALLOW,
984 		 *      an implementation MAY clear the following
985 		 *      mask bits: ACL_WRITE_ACL, ACL_WRITE_OWNER.
986 		 */
987 		if (copy->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
988 			copy->ae_perm &= ~(ACL_WRITE_ACL | ACL_WRITE_OWNER);
989 
990 		/*
991 		 * Increment the counter to skip the copied entry.
992 		 */
993 		i++;
994 	}
995 
996 	/*
997 	 * 3. To ensure that the mode is honored, apply the algorithm describe
998 	 *    in Section 2.16.6.3, using the mode that is to be used for file
999 	 *    creation.
1000 	 */
1001 	acl_nfs4_sync_acl_from_mode(child_aclp, mode, file_owner_id);
1002 }
1003 
1004 /*
1005  * Populate the ACL with entries inherited from parent_aclp.
1006  */
1007 static void
1008 acl_nfs4_inherit_entries(const struct acl *parent_aclp,
1009     struct acl *child_aclp, mode_t mode, int file_owner_id,
1010     int is_directory)
1011 {
1012 	int i, flags, tag;
1013 	const struct acl_entry *parent_entry;
1014 	struct acl_entry *entry;
1015 
1016 	KASSERT(parent_aclp->acl_cnt > 0, ("parent_aclp->acl_cnt > 0"));
1017 	KASSERT(parent_aclp->acl_cnt <= ACL_MAX_ENTRIES,
1018 	    ("parent_aclp->acl_cnt <= ACL_MAX_ENTRIES"));
1019 
1020 	for (i = 0; i < parent_aclp->acl_cnt; i++) {
1021 		parent_entry = &(parent_aclp->acl_entry[i]);
1022 		flags = parent_entry->ae_flags;
1023 		tag = parent_entry->ae_tag;
1024 
1025 		/*
1026 		 * Don't inherit owner@, group@, or everyone@ entries.
1027 		 */
1028 		if (tag == ACL_USER_OBJ || tag == ACL_GROUP_OBJ ||
1029 		    tag == ACL_EVERYONE)
1030 			continue;
1031 
1032 		/*
1033 		 * Entry is not inheritable at all.
1034 		 */
1035 		if ((flags & (ACL_ENTRY_DIRECTORY_INHERIT |
1036 		    ACL_ENTRY_FILE_INHERIT)) == 0)
1037 			continue;
1038 
1039 		/*
1040 		 * We're creating a file, but entry is not inheritable
1041 		 * by files.
1042 		 */
1043 		if (!is_directory && (flags & ACL_ENTRY_FILE_INHERIT) == 0)
1044 			continue;
1045 
1046 		/*
1047 		 * Entry is inheritable only by files, but has NO_PROPAGATE
1048 		 * flag set, and we're creating a directory, so it wouldn't
1049 		 * propagate to any file in that directory anyway.
1050 		 */
1051 		if (is_directory &&
1052 		    (flags & ACL_ENTRY_DIRECTORY_INHERIT) == 0 &&
1053 		    (flags & ACL_ENTRY_NO_PROPAGATE_INHERIT))
1054 			continue;
1055 
1056 		/*
1057 		 * Entry qualifies for being inherited.
1058 		 */
1059 		KASSERT(child_aclp->acl_cnt + 1 <= ACL_MAX_ENTRIES,
1060 		    ("child_aclp->acl_cnt + 1 <= ACL_MAX_ENTRIES"));
1061 		entry = &(child_aclp->acl_entry[child_aclp->acl_cnt]);
1062 		*entry = *parent_entry;
1063 		child_aclp->acl_cnt++;
1064 
1065 		entry->ae_flags &= ~ACL_ENTRY_INHERIT_ONLY;
1066 
1067 		/*
1068 		 * If the type of the ACE is neither ALLOW nor DENY,
1069 		 * then leave it as it is and proceed to the next one.
1070 		 */
1071 		if (entry->ae_entry_type != ACL_ENTRY_TYPE_ALLOW &&
1072 		    entry->ae_entry_type != ACL_ENTRY_TYPE_DENY)
1073 			continue;
1074 
1075 		/*
1076 		 * If the ACL_ENTRY_NO_PROPAGATE_INHERIT is set, or if
1077 		 * the object being created is not a directory, then clear
1078 		 * the following flags: ACL_ENTRY_NO_PROPAGATE_INHERIT,
1079 		 * ACL_ENTRY_FILE_INHERIT, ACL_ENTRY_DIRECTORY_INHERIT,
1080 		 * ACL_ENTRY_INHERIT_ONLY.
1081 		 */
1082 		if (entry->ae_flags & ACL_ENTRY_NO_PROPAGATE_INHERIT ||
1083 		    !is_directory) {
1084 			entry->ae_flags &= ~(ACL_ENTRY_NO_PROPAGATE_INHERIT |
1085 			ACL_ENTRY_FILE_INHERIT | ACL_ENTRY_DIRECTORY_INHERIT |
1086 			ACL_ENTRY_INHERIT_ONLY);
1087 		}
1088 
1089 		/*
1090 		 * If the object is a directory and ACL_ENTRY_FILE_INHERIT
1091 		 * is set, but ACL_ENTRY_DIRECTORY_INHERIT is not set, ensure
1092 		 * that ACL_ENTRY_INHERIT_ONLY is set.
1093 		 */
1094 		if (is_directory &&
1095 		    (entry->ae_flags & ACL_ENTRY_FILE_INHERIT) &&
1096 		    ((entry->ae_flags & ACL_ENTRY_DIRECTORY_INHERIT) == 0)) {
1097 			entry->ae_flags |= ACL_ENTRY_INHERIT_ONLY;
1098 		}
1099 
1100 		if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW &&
1101 		    (entry->ae_flags & ACL_ENTRY_INHERIT_ONLY) == 0) {
1102 			/*
1103 			 * Some permissions must never be inherited.
1104 			 */
1105 			entry->ae_perm &= ~(ACL_WRITE_ACL | ACL_WRITE_OWNER |
1106 			    ACL_WRITE_NAMED_ATTRS | ACL_WRITE_ATTRIBUTES);
1107 
1108 			/*
1109 			 * Others must be masked according to the file mode.
1110 			 */
1111 			if ((mode & S_IRGRP) == 0)
1112 				entry->ae_perm &= ~ACL_READ_DATA;
1113 			if ((mode & S_IWGRP) == 0)
1114 				entry->ae_perm &=
1115 				    ~(ACL_WRITE_DATA | ACL_APPEND_DATA);
1116 			if ((mode & S_IXGRP) == 0)
1117 				entry->ae_perm &= ~ACL_EXECUTE;
1118 		}
1119 	}
1120 }
1121 
1122 /*
1123  * Calculate inherited ACL in a manner compatible with PSARC/2010/029.
1124  * It's also being used to calculate a trivial ACL, by inheriting from
1125  * a NULL ACL.
1126  */
1127 static void
1128 acl_nfs4_compute_inherited_acl_psarc(const struct acl *parent_aclp,
1129     struct acl *aclp, mode_t mode, int file_owner_id, int is_directory)
1130 {
1131 	acl_perm_t user_allow_first = 0, user_deny = 0, group_deny = 0;
1132 	acl_perm_t user_allow, group_allow, everyone_allow;
1133 
1134 	KASSERT(aclp->acl_cnt == 0, ("aclp->acl_cnt == 0"));
1135 
1136 	user_allow = group_allow = everyone_allow = ACL_READ_ACL |
1137 	    ACL_READ_ATTRIBUTES | ACL_READ_NAMED_ATTRS | ACL_SYNCHRONIZE;
1138 	user_allow |= ACL_WRITE_ACL | ACL_WRITE_OWNER | ACL_WRITE_ATTRIBUTES |
1139 	    ACL_WRITE_NAMED_ATTRS;
1140 
1141 	if (mode & S_IRUSR)
1142 		user_allow |= ACL_READ_DATA;
1143 	if (mode & S_IWUSR)
1144 		user_allow |= (ACL_WRITE_DATA | ACL_APPEND_DATA);
1145 	if (mode & S_IXUSR)
1146 		user_allow |= ACL_EXECUTE;
1147 
1148 	if (mode & S_IRGRP)
1149 		group_allow |= ACL_READ_DATA;
1150 	if (mode & S_IWGRP)
1151 		group_allow |= (ACL_WRITE_DATA | ACL_APPEND_DATA);
1152 	if (mode & S_IXGRP)
1153 		group_allow |= ACL_EXECUTE;
1154 
1155 	if (mode & S_IROTH)
1156 		everyone_allow |= ACL_READ_DATA;
1157 	if (mode & S_IWOTH)
1158 		everyone_allow |= (ACL_WRITE_DATA | ACL_APPEND_DATA);
1159 	if (mode & S_IXOTH)
1160 		everyone_allow |= ACL_EXECUTE;
1161 
1162 	user_deny = ((group_allow | everyone_allow) & ~user_allow);
1163 	group_deny = everyone_allow & ~group_allow;
1164 	user_allow_first = group_deny & ~user_deny;
1165 
1166 	if (user_allow_first != 0)
1167 		_acl_append(aclp, ACL_USER_OBJ, user_allow_first,
1168 		    ACL_ENTRY_TYPE_ALLOW);
1169 	if (user_deny != 0)
1170 		_acl_append(aclp, ACL_USER_OBJ, user_deny,
1171 		    ACL_ENTRY_TYPE_DENY);
1172 	if (group_deny != 0)
1173 		_acl_append(aclp, ACL_GROUP_OBJ, group_deny,
1174 		    ACL_ENTRY_TYPE_DENY);
1175 
1176 	if (parent_aclp != NULL)
1177 		acl_nfs4_inherit_entries(parent_aclp, aclp, mode,
1178 		    file_owner_id, is_directory);
1179 
1180 	_acl_append(aclp, ACL_USER_OBJ, user_allow, ACL_ENTRY_TYPE_ALLOW);
1181 	_acl_append(aclp, ACL_GROUP_OBJ, group_allow, ACL_ENTRY_TYPE_ALLOW);
1182 	_acl_append(aclp, ACL_EVERYONE, everyone_allow, ACL_ENTRY_TYPE_ALLOW);
1183 }
1184 
1185 void
1186 acl_nfs4_compute_inherited_acl(const struct acl *parent_aclp,
1187     struct acl *child_aclp, mode_t mode, int file_owner_id,
1188     int is_directory)
1189 {
1190 
1191 	if (acl_nfs4_old_semantics)
1192 		acl_nfs4_compute_inherited_acl_draft(parent_aclp, child_aclp,
1193 		    mode, file_owner_id, is_directory);
1194 	else
1195 		acl_nfs4_compute_inherited_acl_psarc(parent_aclp, child_aclp,
1196 		    mode, file_owner_id, is_directory);
1197 }
1198 
1199 /*
1200  * Calculate trivial ACL in a manner compatible with PSARC/2010/029.
1201  * Note that this results in an ACL different from (but semantically
1202  * equal to) the "canonical six" trivial ACL computed using algorithm
1203  * described in draft-ietf-nfsv4-minorversion1-03.txt, 3.16.6.2.
1204  *
1205  * This routine is not static only because the code is being used in libc.
1206  * Kernel code should call acl_nfs4_sync_acl_from_mode() instead.
1207  */
1208 void
1209 acl_nfs4_trivial_from_mode(struct acl *aclp, mode_t mode)
1210 {
1211 
1212 	aclp->acl_cnt = 0;
1213 	acl_nfs4_compute_inherited_acl_psarc(NULL, aclp, mode, -1, -1);
1214 }
1215 
1216 #ifdef _KERNEL
1217 static int
1218 _acls_are_equal(const struct acl *a, const struct acl *b)
1219 {
1220 	int i;
1221 	const struct acl_entry *entrya, *entryb;
1222 
1223 	if (a->acl_cnt != b->acl_cnt)
1224 		return (0);
1225 
1226 	for (i = 0; i < b->acl_cnt; i++) {
1227 		entrya = &(a->acl_entry[i]);
1228 		entryb = &(b->acl_entry[i]);
1229 
1230 		if (entrya->ae_tag != entryb->ae_tag ||
1231 		    entrya->ae_id != entryb->ae_id ||
1232 		    entrya->ae_perm != entryb->ae_perm ||
1233 		    entrya->ae_entry_type != entryb->ae_entry_type ||
1234 		    entrya->ae_flags != entryb->ae_flags)
1235 			return (0);
1236 	}
1237 
1238 	return (1);
1239 }
1240 
1241 /*
1242  * This routine is used to determine whether to remove extended attribute
1243  * that stores ACL contents.
1244  */
1245 int
1246 acl_nfs4_is_trivial(const struct acl *aclp, int file_owner_id)
1247 {
1248 	int trivial;
1249 	mode_t tmpmode = 0;
1250 	struct acl *tmpaclp;
1251 
1252 	if (aclp->acl_cnt > 6)
1253 		return (0);
1254 
1255 	/*
1256 	 * Compute the mode from the ACL, then compute new ACL from that mode.
1257 	 * If the ACLs are identical, then the ACL is trivial.
1258 	 *
1259 	 * XXX: I guess there is a faster way to do this.  However, even
1260 	 *      this slow implementation significantly speeds things up
1261 	 *      for files that don't have non-trivial ACLs - it's critical
1262 	 *      for performance to not use EA when they are not needed.
1263 	 *
1264 	 * First try the PSARC/2010/029 semantics.
1265 	 */
1266 	tmpaclp = acl_alloc(M_WAITOK | M_ZERO);
1267 	acl_nfs4_sync_mode_from_acl(&tmpmode, aclp);
1268 	acl_nfs4_trivial_from_mode(tmpaclp, tmpmode);
1269 	trivial = _acls_are_equal(aclp, tmpaclp);
1270 	if (trivial) {
1271 		acl_free(tmpaclp);
1272 		return (trivial);
1273 	}
1274 
1275 	/*
1276 	 * Check if it's a draft-ietf-nfsv4-minorversion1-03.txt trivial ACL.
1277 	 */
1278 	tmpaclp->acl_cnt = 0;
1279 	acl_nfs4_sync_acl_from_mode_draft(tmpaclp, tmpmode, file_owner_id);
1280 	trivial = _acls_are_equal(aclp, tmpaclp);
1281 	acl_free(tmpaclp);
1282 
1283 	return (trivial);
1284 }
1285 #endif /* _KERNEL */
1286 
1287 int
1288 acl_nfs4_check(const struct acl *aclp, int is_directory)
1289 {
1290 	int i;
1291 	const struct acl_entry *entry;
1292 
1293 	/*
1294 	 * The spec doesn't seem to say anything about ACL validity.
1295 	 * It seems there is not much to do here.  There is even no need
1296 	 * to count "owner@" or "everyone@" (ACL_USER_OBJ and ACL_EVERYONE)
1297 	 * entries, as there can be several of them and that's perfectly
1298 	 * valid.  There can be none of them too.  Really.
1299 	 */
1300 
1301 	if (aclp->acl_cnt > ACL_MAX_ENTRIES || aclp->acl_cnt <= 0)
1302 		return (EINVAL);
1303 
1304 	for (i = 0; i < aclp->acl_cnt; i++) {
1305 		entry = &(aclp->acl_entry[i]);
1306 
1307 		switch (entry->ae_tag) {
1308 		case ACL_USER_OBJ:
1309 		case ACL_GROUP_OBJ:
1310 		case ACL_EVERYONE:
1311 			if (entry->ae_id != ACL_UNDEFINED_ID)
1312 				return (EINVAL);
1313 			break;
1314 
1315 		case ACL_USER:
1316 		case ACL_GROUP:
1317 			if (entry->ae_id == ACL_UNDEFINED_ID)
1318 				return (EINVAL);
1319 			break;
1320 
1321 		default:
1322 			return (EINVAL);
1323 		}
1324 
1325 		if ((entry->ae_perm | ACL_NFS4_PERM_BITS) != ACL_NFS4_PERM_BITS)
1326 			return (EINVAL);
1327 
1328 		/*
1329 		 * Disallow ACL_ENTRY_TYPE_AUDIT and ACL_ENTRY_TYPE_ALARM for now.
1330 		 */
1331 		if (entry->ae_entry_type != ACL_ENTRY_TYPE_ALLOW &&
1332 		    entry->ae_entry_type != ACL_ENTRY_TYPE_DENY)
1333 			return (EINVAL);
1334 
1335 		if ((entry->ae_flags | ACL_FLAGS_BITS) != ACL_FLAGS_BITS)
1336 			return (EINVAL);
1337 
1338 		/* Disallow unimplemented flags. */
1339 		if (entry->ae_flags & (ACL_ENTRY_SUCCESSFUL_ACCESS |
1340 		    ACL_ENTRY_FAILED_ACCESS))
1341 			return (EINVAL);
1342 
1343 		/* Disallow flags not allowed for ordinary files. */
1344 		if (!is_directory) {
1345 			if (entry->ae_flags & (ACL_ENTRY_FILE_INHERIT |
1346 			    ACL_ENTRY_DIRECTORY_INHERIT |
1347 			    ACL_ENTRY_NO_PROPAGATE_INHERIT | ACL_ENTRY_INHERIT_ONLY))
1348 				return (EINVAL);
1349 		}
1350 	}
1351 
1352 	return (0);
1353 }
1354