xref: /freebsd/sys/kern/subr_acl_nfs4.c (revision 22cf89c938886d14f5796fc49f9f020c23ea8eaf)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2008-2010 Edward Tomasz Napierała <trasz@FreeBSD.org>
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
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 AND CONTRIBUTORS ``AS IS'' AND
16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25  * SUCH DAMAGE.
26  */
27 
28 /*
29  * ACL support routines specific to NFSv4 access control lists.  These are
30  * utility routines for code common across file systems implementing NFSv4
31  * ACLs.
32  */
33 
34 #ifdef _KERNEL
35 #include <sys/cdefs.h>
36 #include <sys/param.h>
37 #include <sys/kernel.h>
38 #include <sys/module.h>
39 #include <sys/systm.h>
40 #include <sys/mount.h>
41 #include <sys/priv.h>
42 #include <sys/vnode.h>
43 #include <sys/errno.h>
44 #include <sys/stat.h>
45 #include <sys/sysctl.h>
46 #include <sys/acl.h>
47 #else
48 #include <errno.h>
49 #include <assert.h>
50 #include <sys/acl.h>
51 #include <sys/stat.h>
52 #define KASSERT(a, b) assert(a)
53 #define CTASSERT(a)
54 
55 #endif /* !_KERNEL */
56 
57 #ifdef _KERNEL
58 
59 static void	acl_nfs4_trivial_from_mode(struct acl *aclp, mode_t mode);
60 
61 static int	acl_nfs4_old_semantics = 0;
62 
63 SYSCTL_INT(_vfs, OID_AUTO, acl_nfs4_old_semantics, CTLFLAG_RW,
64     &acl_nfs4_old_semantics, 0, "Use pre-PSARC/2010/029 NFSv4 ACL semantics");
65 
66 static struct {
67 	accmode_t accmode;
68 	int mask;
69 } accmode2mask[] = {{VREAD, ACL_READ_DATA},
70 		    {VWRITE, ACL_WRITE_DATA},
71 		    {VAPPEND, ACL_APPEND_DATA},
72 		    {VEXEC, ACL_EXECUTE},
73 		    {VREAD_NAMED_ATTRS, ACL_READ_NAMED_ATTRS},
74 		    {VWRITE_NAMED_ATTRS, ACL_WRITE_NAMED_ATTRS},
75 		    {VDELETE_CHILD, ACL_DELETE_CHILD},
76 		    {VREAD_ATTRIBUTES, ACL_READ_ATTRIBUTES},
77 		    {VWRITE_ATTRIBUTES, ACL_WRITE_ATTRIBUTES},
78 		    {VDELETE, ACL_DELETE},
79 		    {VREAD_ACL, ACL_READ_ACL},
80 		    {VWRITE_ACL, ACL_WRITE_ACL},
81 		    {VWRITE_OWNER, ACL_WRITE_OWNER},
82 		    {VSYNCHRONIZE, ACL_SYNCHRONIZE},
83 		    {0, 0}};
84 
85 static int
86 _access_mask_from_accmode(accmode_t accmode)
87 {
88 	int access_mask = 0, i;
89 
90 	for (i = 0; accmode2mask[i].accmode != 0; i++) {
91 		if (accmode & accmode2mask[i].accmode)
92 			access_mask |= accmode2mask[i].mask;
93 	}
94 
95 	/*
96 	 * VAPPEND is just a modifier for VWRITE; if the caller asked
97 	 * for 'VAPPEND | VWRITE', we want to check for ACL_APPEND_DATA only.
98 	 */
99 	if (access_mask & ACL_APPEND_DATA)
100 		access_mask &= ~ACL_WRITE_DATA;
101 
102 	return (access_mask);
103 }
104 
105 /*
106  * Return 0, iff access is allowed, 1 otherwise.
107  */
108 static int
109 _acl_denies(const struct acl *aclp, int access_mask, struct ucred *cred,
110     int file_uid, int file_gid, int *denied_explicitly)
111 {
112 	int i;
113 	const struct acl_entry *entry;
114 
115 	if (denied_explicitly != NULL)
116 		*denied_explicitly = 0;
117 
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 	if (access_mask == 0)
165 		return (0);
166 
167 	return (1);
168 }
169 
170 int
171 vaccess_acl_nfs4(__enum_uint8(vtype) type, uid_t file_uid, gid_t file_gid,
172     struct acl *aclp, accmode_t accmode, struct ucred *cred)
173 {
174 	accmode_t priv_granted = 0;
175 	int denied, explicitly_denied, access_mask, is_directory,
176 	    must_be_owner = 0;
177 	mode_t file_mode = 0;
178 
179 	KASSERT((accmode & ~(VEXEC | VWRITE | VREAD | VADMIN | VAPPEND |
180 	    VEXPLICIT_DENY | VREAD_NAMED_ATTRS | VWRITE_NAMED_ATTRS |
181 	    VDELETE_CHILD | VREAD_ATTRIBUTES | VWRITE_ATTRIBUTES | VDELETE |
182 	    VREAD_ACL | VWRITE_ACL | VWRITE_OWNER | VSYNCHRONIZE)) == 0,
183 	    ("invalid bit in accmode"));
184 	KASSERT((accmode & VAPPEND) == 0 || (accmode & VWRITE),
185 	    	("VAPPEND without VWRITE"));
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, PRIV_VFS_LOOKUP))
257 			priv_granted |= VEXEC;
258 	} else {
259 		/*
260 		 * Ensure that at least one execute bit is on. Otherwise,
261 		 * a privileged user will always succeed, and we don't want
262 		 * this to happen unless the file really is executable.
263 		 */
264 		if ((accmode & VEXEC) && (file_mode &
265 		    (S_IXUSR | S_IXGRP | S_IXOTH)) != 0 &&
266 		    !priv_check_cred(cred, PRIV_VFS_EXEC))
267 			priv_granted |= VEXEC;
268 	}
269 
270 	if ((accmode & VREAD) && !priv_check_cred(cred, PRIV_VFS_READ))
271 		priv_granted |= VREAD;
272 
273 	if ((accmode & (VWRITE | VAPPEND | VDELETE_CHILD)) &&
274 	    !priv_check_cred(cred, PRIV_VFS_WRITE))
275 		priv_granted |= (VWRITE | VAPPEND | VDELETE_CHILD);
276 
277 	if ((accmode & VADMIN_PERMS) &&
278 	    !priv_check_cred(cred, PRIV_VFS_ADMIN))
279 		priv_granted |= VADMIN_PERMS;
280 
281 	if ((accmode & VSTAT_PERMS) &&
282 	    !priv_check_cred(cred, PRIV_VFS_STAT))
283 		priv_granted |= VSTAT_PERMS;
284 
285 	if ((accmode & priv_granted) == accmode) {
286 		return (0);
287 	}
288 
289 	if (accmode & (VADMIN_PERMS | VDELETE_CHILD | VDELETE))
290 		denied = EPERM;
291 	else
292 		denied = EACCES;
293 
294 	return (denied);
295 }
296 #endif /* _KERNEL */
297 
298 static int
299 _acl_entry_matches(struct acl_entry *entry, acl_tag_t tag, acl_perm_t perm,
300     acl_entry_type_t entry_type)
301 {
302 	if (entry->ae_tag != tag)
303 		return (0);
304 
305 	if (entry->ae_id != ACL_UNDEFINED_ID)
306 		return (0);
307 
308 	if (entry->ae_perm != perm)
309 		return (0);
310 
311 	if (entry->ae_entry_type != entry_type)
312 		return (0);
313 
314 	if (entry->ae_flags != 0)
315 		return (0);
316 
317 	return (1);
318 }
319 
320 static struct acl_entry *
321 _acl_append(struct acl *aclp, acl_tag_t tag, acl_perm_t perm,
322     acl_entry_type_t entry_type)
323 {
324 	struct acl_entry *entry;
325 
326 	KASSERT(aclp->acl_cnt + 1 <= ACL_MAX_ENTRIES,
327 	    ("aclp->acl_cnt + 1 <= ACL_MAX_ENTRIES"));
328 
329 	entry = &(aclp->acl_entry[aclp->acl_cnt]);
330 	aclp->acl_cnt++;
331 
332 	entry->ae_tag = tag;
333 	entry->ae_id = ACL_UNDEFINED_ID;
334 	entry->ae_perm = perm;
335 	entry->ae_entry_type = entry_type;
336 	entry->ae_flags = 0;
337 
338 	return (entry);
339 }
340 
341 static struct acl_entry *
342 _acl_duplicate_entry(struct acl *aclp, unsigned entry_index)
343 {
344 	unsigned i;
345 
346 	KASSERT(aclp->acl_cnt + 1 <= ACL_MAX_ENTRIES,
347 	    ("aclp->acl_cnt + 1 <= ACL_MAX_ENTRIES"));
348 
349 	for (i = aclp->acl_cnt; i > entry_index; i--)
350 		aclp->acl_entry[i] = aclp->acl_entry[i - 1];
351 
352 	aclp->acl_cnt++;
353 
354 	return (&(aclp->acl_entry[entry_index + 1]));
355 }
356 
357 static void
358 acl_nfs4_sync_acl_from_mode_draft(struct acl *aclp, mode_t mode,
359     int file_owner_id)
360 {
361 	int meets, must_append;
362 	unsigned i;
363 	struct acl_entry *entry, *copy, *previous,
364 	    *a1, *a2, *a3, *a4, *a5, *a6;
365 	mode_t amode;
366 	const int READ = 04;
367 	const int WRITE = 02;
368 	const int EXEC = 01;
369 
370 	KASSERT(aclp->acl_cnt <= ACL_MAX_ENTRIES,
371 	    ("aclp->acl_cnt <= ACL_MAX_ENTRIES"));
372 
373 	/*
374 	 * NFSv4 Minor Version 1, draft-ietf-nfsv4-minorversion1-03.txt
375 	 *
376 	 * 3.16.6.3. Applying a Mode to an Existing ACL
377 	 */
378 
379 	/*
380 	 * 1. For each ACE:
381 	 */
382 	for (i = 0; i < aclp->acl_cnt; i++) {
383 		entry = &(aclp->acl_entry[i]);
384 
385 		/*
386 		 * 1.1. If the type is neither ALLOW or DENY - skip.
387 		 */
388 		if (entry->ae_entry_type != ACL_ENTRY_TYPE_ALLOW &&
389 		    entry->ae_entry_type != ACL_ENTRY_TYPE_DENY)
390 			continue;
391 
392 		/*
393 		 * 1.2. If ACL_ENTRY_INHERIT_ONLY is set - skip.
394 		 */
395 		if (entry->ae_flags & ACL_ENTRY_INHERIT_ONLY)
396 			continue;
397 
398 		/*
399 		 * 1.3. If ACL_ENTRY_FILE_INHERIT or ACL_ENTRY_DIRECTORY_INHERIT
400 		 *      are set:
401 		 */
402 		if (entry->ae_flags &
403 		    (ACL_ENTRY_FILE_INHERIT | ACL_ENTRY_DIRECTORY_INHERIT)) {
404 			/*
405 			 * 1.3.1. A copy of the current ACE is made, and placed
406 			 *        in the ACL immediately following the current
407 			 *        ACE.
408 			 */
409 			copy = _acl_duplicate_entry(aclp, i);
410 
411 			/*
412 			 * 1.3.2. In the first ACE, the flag
413 			 *        ACL_ENTRY_INHERIT_ONLY is set.
414 			 */
415 			entry->ae_flags |= ACL_ENTRY_INHERIT_ONLY;
416 
417 			/*
418 			 * 1.3.3. In the second ACE, the following flags
419 			 *        are cleared:
420 			 *        ACL_ENTRY_FILE_INHERIT,
421 			 *        ACL_ENTRY_DIRECTORY_INHERIT,
422 			 *        ACL_ENTRY_NO_PROPAGATE_INHERIT.
423 			 */
424 			copy->ae_flags &= ~(ACL_ENTRY_FILE_INHERIT |
425 			    ACL_ENTRY_DIRECTORY_INHERIT |
426 			    ACL_ENTRY_NO_PROPAGATE_INHERIT);
427 
428 			/*
429 			 * The algorithm continues on with the second ACE.
430 			 */
431 			i++;
432 			entry = copy;
433 		}
434 
435 		/*
436 		 * 1.4. If it's owner@, group@ or everyone@ entry, clear
437 		 *      ACL_READ_DATA, ACL_WRITE_DATA, ACL_APPEND_DATA
438 		 *      and ACL_EXECUTE.  Continue to the next entry.
439 		 */
440 		if (entry->ae_tag == ACL_USER_OBJ ||
441 		    entry->ae_tag == ACL_GROUP_OBJ ||
442 		    entry->ae_tag == ACL_EVERYONE) {
443 			entry->ae_perm &= ~(ACL_READ_DATA | ACL_WRITE_DATA |
444 			    ACL_APPEND_DATA | ACL_EXECUTE);
445 			continue;
446 		}
447 
448 		/*
449 		 * 1.5. Otherwise, if the "who" field did not match one
450 		 *      of OWNER@, GROUP@, EVERYONE@:
451 		 *
452 		 * 1.5.1. If the type is ALLOW, check the preceding ACE.
453 		 *        If it does not meet all of the following criteria:
454 		 */
455 		if (entry->ae_entry_type != ACL_ENTRY_TYPE_ALLOW)
456 			continue;
457 
458 		meets = 0;
459 		if (i > 0) {
460 			meets = 1;
461 			previous = &(aclp->acl_entry[i - 1]);
462 
463 			/*
464 			 * 1.5.1.1. The type field is DENY,
465 			 */
466 			if (previous->ae_entry_type != ACL_ENTRY_TYPE_DENY)
467 				meets = 0;
468 
469 			/*
470 			 * 1.5.1.2. The "who" field is the same as the current
471 			 *          ACE,
472 			 *
473 			 * 1.5.1.3. The flag bit ACE4_IDENTIFIER_GROUP
474 			 *          is the same as it is in the current ACE,
475 			 *          and no other flag bits are set,
476 			 */
477 			if (previous->ae_id != entry->ae_id ||
478 			    previous->ae_tag != entry->ae_tag)
479 				meets = 0;
480 
481 			if (previous->ae_flags)
482 				meets = 0;
483 
484 			/*
485 			 * 1.5.1.4. The mask bits are a subset of the mask bits
486 			 *          of the current ACE, and are also subset of
487 			 *          the following: ACL_READ_DATA,
488 			 *          ACL_WRITE_DATA, ACL_APPEND_DATA, ACL_EXECUTE
489 			 */
490 			if (previous->ae_perm & ~(entry->ae_perm))
491 				meets = 0;
492 
493 			if (previous->ae_perm & ~(ACL_READ_DATA |
494 			    ACL_WRITE_DATA | ACL_APPEND_DATA | ACL_EXECUTE))
495 				meets = 0;
496 		}
497 
498 		if (!meets) {
499 			/*
500 		 	 * Then the ACE of type DENY, with a who equal
501 			 * to the current ACE, flag bits equal to
502 			 * (<current ACE flags> & <ACE_IDENTIFIER_GROUP>)
503 			 * and no mask bits, is prepended.
504 			 */
505 			previous = entry;
506 			entry = _acl_duplicate_entry(aclp, i);
507 
508 			/* Adjust counter, as we've just added an entry. */
509 			i++;
510 
511 			previous->ae_tag = entry->ae_tag;
512 			previous->ae_id = entry->ae_id;
513 			previous->ae_flags = entry->ae_flags;
514 			previous->ae_perm = 0;
515 			previous->ae_entry_type = ACL_ENTRY_TYPE_DENY;
516 		}
517 
518 		/*
519 		 * 1.5.2. The following modifications are made to the prepended
520 		 *        ACE.  The intent is to mask the following ACE
521 		 *        to disallow ACL_READ_DATA, ACL_WRITE_DATA,
522 		 *        ACL_APPEND_DATA, or ACL_EXECUTE, based upon the group
523 		 *        permissions of the new mode.  As a special case,
524 		 *        if the ACE matches the current owner of the file,
525 		 *        the owner bits are used, rather than the group bits.
526 		 *        This is reflected in the algorithm below.
527 		 */
528 		amode = mode >> 3;
529 
530 		/*
531 		 * If ACE4_IDENTIFIER_GROUP is not set, and the "who" field
532 		 * in ACE matches the owner of the file, we shift amode three
533 		 * more bits, in order to have the owner permission bits
534 		 * placed in the three low order bits of amode.
535 		 */
536 		if (entry->ae_tag == ACL_USER && entry->ae_id == file_owner_id)
537 			amode = amode >> 3;
538 
539 		if (entry->ae_perm & ACL_READ_DATA) {
540 			if (amode & READ)
541 				previous->ae_perm &= ~ACL_READ_DATA;
542 			else
543 				previous->ae_perm |= ACL_READ_DATA;
544 		}
545 
546 		if (entry->ae_perm & ACL_WRITE_DATA) {
547 			if (amode & WRITE)
548 				previous->ae_perm &= ~ACL_WRITE_DATA;
549 			else
550 				previous->ae_perm |= ACL_WRITE_DATA;
551 		}
552 
553 		if (entry->ae_perm & ACL_APPEND_DATA) {
554 			if (amode & WRITE)
555 				previous->ae_perm &= ~ACL_APPEND_DATA;
556 			else
557 				previous->ae_perm |= ACL_APPEND_DATA;
558 		}
559 
560 		if (entry->ae_perm & ACL_EXECUTE) {
561 			if (amode & EXEC)
562 				previous->ae_perm &= ~ACL_EXECUTE;
563 			else
564 				previous->ae_perm |= ACL_EXECUTE;
565 		}
566 
567 		/*
568 		 * 1.5.3. If ACE4_IDENTIFIER_GROUP is set in the flags
569 		 *        of the ALLOW ace:
570 		 *
571 		 * XXX: This point is not there in the Falkner's draft.
572 		 */
573 		if (entry->ae_tag == ACL_GROUP &&
574 		    entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW) {
575 			mode_t extramode, ownermode;
576 			extramode = (mode >> 3) & 07;
577 			ownermode = mode >> 6;
578 			extramode &= ~ownermode;
579 
580 			if (extramode) {
581 				if (extramode & READ) {
582 					entry->ae_perm &= ~ACL_READ_DATA;
583 					previous->ae_perm &= ~ACL_READ_DATA;
584 				}
585 
586 				if (extramode & WRITE) {
587 					entry->ae_perm &=
588 					    ~(ACL_WRITE_DATA | ACL_APPEND_DATA);
589 					previous->ae_perm &=
590 					    ~(ACL_WRITE_DATA | ACL_APPEND_DATA);
591 				}
592 
593 				if (extramode & EXEC) {
594 					entry->ae_perm &= ~ACL_EXECUTE;
595 					previous->ae_perm &= ~ACL_EXECUTE;
596 				}
597 			}
598 		}
599 	}
600 
601 	/*
602 	 * 2. If there at least six ACEs, the final six ACEs are examined.
603 	 *    If they are not equal to what we want, append six ACEs.
604 	 */
605 	must_append = 0;
606 	if (aclp->acl_cnt < 6) {
607 		must_append = 1;
608 	} else {
609 		a6 = &(aclp->acl_entry[aclp->acl_cnt - 1]);
610 		a5 = &(aclp->acl_entry[aclp->acl_cnt - 2]);
611 		a4 = &(aclp->acl_entry[aclp->acl_cnt - 3]);
612 		a3 = &(aclp->acl_entry[aclp->acl_cnt - 4]);
613 		a2 = &(aclp->acl_entry[aclp->acl_cnt - 5]);
614 		a1 = &(aclp->acl_entry[aclp->acl_cnt - 6]);
615 
616 		if (!_acl_entry_matches(a1, ACL_USER_OBJ, 0,
617 		    ACL_ENTRY_TYPE_DENY))
618 			must_append = 1;
619 		if (!_acl_entry_matches(a2, ACL_USER_OBJ, ACL_WRITE_ACL |
620 		    ACL_WRITE_OWNER | ACL_WRITE_ATTRIBUTES |
621 		    ACL_WRITE_NAMED_ATTRS, ACL_ENTRY_TYPE_ALLOW))
622 			must_append = 1;
623 		if (!_acl_entry_matches(a3, ACL_GROUP_OBJ, 0,
624 		    ACL_ENTRY_TYPE_DENY))
625 			must_append = 1;
626 		if (!_acl_entry_matches(a4, ACL_GROUP_OBJ, 0,
627 		    ACL_ENTRY_TYPE_ALLOW))
628 			must_append = 1;
629 		if (!_acl_entry_matches(a5, ACL_EVERYONE, ACL_WRITE_ACL |
630 		    ACL_WRITE_OWNER | ACL_WRITE_ATTRIBUTES |
631 		    ACL_WRITE_NAMED_ATTRS, ACL_ENTRY_TYPE_DENY))
632 			must_append = 1;
633 		if (!_acl_entry_matches(a6, ACL_EVERYONE, ACL_READ_ACL |
634 		    ACL_READ_ATTRIBUTES | ACL_READ_NAMED_ATTRS |
635 		    ACL_SYNCHRONIZE, ACL_ENTRY_TYPE_ALLOW))
636 			must_append = 1;
637 	}
638 
639 	if (must_append) {
640 		KASSERT(aclp->acl_cnt + 6 <= ACL_MAX_ENTRIES,
641 		    ("aclp->acl_cnt <= ACL_MAX_ENTRIES"));
642 
643 		a1 = _acl_append(aclp, ACL_USER_OBJ, 0, ACL_ENTRY_TYPE_DENY);
644 		a2 = _acl_append(aclp, ACL_USER_OBJ, ACL_WRITE_ACL |
645 		    ACL_WRITE_OWNER | ACL_WRITE_ATTRIBUTES |
646 		    ACL_WRITE_NAMED_ATTRS, ACL_ENTRY_TYPE_ALLOW);
647 		a3 = _acl_append(aclp, ACL_GROUP_OBJ, 0, ACL_ENTRY_TYPE_DENY);
648 		a4 = _acl_append(aclp, ACL_GROUP_OBJ, 0, ACL_ENTRY_TYPE_ALLOW);
649 		a5 = _acl_append(aclp, ACL_EVERYONE, ACL_WRITE_ACL |
650 		    ACL_WRITE_OWNER | ACL_WRITE_ATTRIBUTES |
651 		    ACL_WRITE_NAMED_ATTRS, ACL_ENTRY_TYPE_DENY);
652 		a6 = _acl_append(aclp, ACL_EVERYONE, ACL_READ_ACL |
653 		    ACL_READ_ATTRIBUTES | ACL_READ_NAMED_ATTRS |
654 		    ACL_SYNCHRONIZE, ACL_ENTRY_TYPE_ALLOW);
655 
656 		KASSERT(a1 != NULL && a2 != NULL && a3 != NULL && a4 != NULL &&
657 		    a5 != NULL && a6 != NULL, ("couldn't append to ACL."));
658 	}
659 
660 	/*
661 	 * 3. The final six ACEs are adjusted according to the incoming mode.
662 	 */
663 	if (mode & S_IRUSR)
664 		a2->ae_perm |= ACL_READ_DATA;
665 	else
666 		a1->ae_perm |= ACL_READ_DATA;
667 	if (mode & S_IWUSR)
668 		a2->ae_perm |= (ACL_WRITE_DATA | ACL_APPEND_DATA);
669 	else
670 		a1->ae_perm |= (ACL_WRITE_DATA | ACL_APPEND_DATA);
671 	if (mode & S_IXUSR)
672 		a2->ae_perm |= ACL_EXECUTE;
673 	else
674 		a1->ae_perm |= ACL_EXECUTE;
675 
676 	if (mode & S_IRGRP)
677 		a4->ae_perm |= ACL_READ_DATA;
678 	else
679 		a3->ae_perm |= ACL_READ_DATA;
680 	if (mode & S_IWGRP)
681 		a4->ae_perm |= (ACL_WRITE_DATA | ACL_APPEND_DATA);
682 	else
683 		a3->ae_perm |= (ACL_WRITE_DATA | ACL_APPEND_DATA);
684 	if (mode & S_IXGRP)
685 		a4->ae_perm |= ACL_EXECUTE;
686 	else
687 		a3->ae_perm |= ACL_EXECUTE;
688 
689 	if (mode & S_IROTH)
690 		a6->ae_perm |= ACL_READ_DATA;
691 	else
692 		a5->ae_perm |= ACL_READ_DATA;
693 	if (mode & S_IWOTH)
694 		a6->ae_perm |= (ACL_WRITE_DATA | ACL_APPEND_DATA);
695 	else
696 		a5->ae_perm |= (ACL_WRITE_DATA | ACL_APPEND_DATA);
697 	if (mode & S_IXOTH)
698 		a6->ae_perm |= ACL_EXECUTE;
699 	else
700 		a5->ae_perm |= ACL_EXECUTE;
701 }
702 
703 #ifdef _KERNEL
704 void
705 acl_nfs4_sync_acl_from_mode(struct acl *aclp, mode_t mode,
706     int file_owner_id)
707 {
708 
709 	if (acl_nfs4_old_semantics)
710 		acl_nfs4_sync_acl_from_mode_draft(aclp, mode, file_owner_id);
711 	else
712 		acl_nfs4_trivial_from_mode(aclp, mode);
713 }
714 #endif /* _KERNEL */
715 
716 void
717 acl_nfs4_sync_mode_from_acl(mode_t *_mode, const struct acl *aclp)
718 {
719 	int i;
720 	mode_t old_mode = *_mode, mode = 0, seen = 0;
721 	const struct acl_entry *entry;
722 
723 	KASSERT(aclp->acl_cnt <= ACL_MAX_ENTRIES,
724 	    ("aclp->acl_cnt <= ACL_MAX_ENTRIES"));
725 
726 	/*
727 	 * NFSv4 Minor Version 1, draft-ietf-nfsv4-minorversion1-03.txt
728 	 *
729 	 * 3.16.6.1. Recomputing mode upon SETATTR of ACL
730 	 */
731 
732 	for (i = 0; i < aclp->acl_cnt; i++) {
733 		entry = &(aclp->acl_entry[i]);
734 
735 		if (entry->ae_entry_type != ACL_ENTRY_TYPE_ALLOW &&
736 		    entry->ae_entry_type != ACL_ENTRY_TYPE_DENY)
737 			continue;
738 
739 		if (entry->ae_flags & ACL_ENTRY_INHERIT_ONLY)
740 			continue;
741 
742 		if (entry->ae_tag == ACL_USER_OBJ) {
743 			if ((entry->ae_perm & ACL_READ_DATA) &&
744 			    ((seen & S_IRUSR) == 0)) {
745 				seen |= S_IRUSR;
746 				if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
747 					mode |= S_IRUSR;
748 			}
749 			if ((entry->ae_perm & ACL_WRITE_DATA) &&
750 			     ((seen & S_IWUSR) == 0)) {
751 				seen |= S_IWUSR;
752 				if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
753 					mode |= S_IWUSR;
754 			}
755 			if ((entry->ae_perm & ACL_EXECUTE) &&
756 			    ((seen & S_IXUSR) == 0)) {
757 				seen |= S_IXUSR;
758 				if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
759 					mode |= S_IXUSR;
760 			}
761 		} else if (entry->ae_tag == ACL_GROUP_OBJ) {
762 			if ((entry->ae_perm & ACL_READ_DATA) &&
763 			    ((seen & S_IRGRP) == 0)) {
764 				seen |= S_IRGRP;
765 				if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
766 					mode |= S_IRGRP;
767 			}
768 			if ((entry->ae_perm & ACL_WRITE_DATA) &&
769 			    ((seen & S_IWGRP) == 0)) {
770 				seen |= S_IWGRP;
771 				if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
772 					mode |= S_IWGRP;
773 			}
774 			if ((entry->ae_perm & ACL_EXECUTE) &&
775 			    ((seen & S_IXGRP) == 0)) {
776 				seen |= S_IXGRP;
777 				if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
778 					mode |= S_IXGRP;
779 			}
780 		} else if (entry->ae_tag == ACL_EVERYONE) {
781 			if (entry->ae_perm & ACL_READ_DATA) {
782 				if ((seen & S_IRUSR) == 0) {
783 					seen |= S_IRUSR;
784 					if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
785 						mode |= S_IRUSR;
786 				}
787 				if ((seen & S_IRGRP) == 0) {
788 					seen |= S_IRGRP;
789 					if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
790 						mode |= S_IRGRP;
791 				}
792 				if ((seen & S_IROTH) == 0) {
793 					seen |= S_IROTH;
794 					if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
795 						mode |= S_IROTH;
796 				}
797 			}
798 			if (entry->ae_perm & ACL_WRITE_DATA) {
799 				if ((seen & S_IWUSR) == 0) {
800 					seen |= S_IWUSR;
801 					if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
802 						mode |= S_IWUSR;
803 				}
804 				if ((seen & S_IWGRP) == 0) {
805 					seen |= S_IWGRP;
806 					if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
807 						mode |= S_IWGRP;
808 				}
809 				if ((seen & S_IWOTH) == 0) {
810 					seen |= S_IWOTH;
811 					if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
812 						mode |= S_IWOTH;
813 				}
814 			}
815 			if (entry->ae_perm & ACL_EXECUTE) {
816 				if ((seen & S_IXUSR) == 0) {
817 					seen |= S_IXUSR;
818 					if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
819 						mode |= S_IXUSR;
820 				}
821 				if ((seen & S_IXGRP) == 0) {
822 					seen |= S_IXGRP;
823 					if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
824 						mode |= S_IXGRP;
825 				}
826 				if ((seen & S_IXOTH) == 0) {
827 					seen |= S_IXOTH;
828 					if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
829 						mode |= S_IXOTH;
830 				}
831 			}
832 		}
833 	}
834 
835 	*_mode = mode | (old_mode & ACL_PRESERVE_MASK);
836 }
837 
838 #ifdef _KERNEL
839 /*
840  * Calculate inherited ACL in a manner compatible with NFSv4 Minor Version 1,
841  * draft-ietf-nfsv4-minorversion1-03.txt.
842  */
843 static void
844 acl_nfs4_compute_inherited_acl_draft(const struct acl *parent_aclp,
845     struct acl *child_aclp, mode_t mode, int file_owner_id,
846     int is_directory)
847 {
848 	int i, flags;
849 	const struct acl_entry *parent_entry;
850 	struct acl_entry *entry, *copy;
851 
852 	KASSERT(child_aclp->acl_cnt == 0, ("child_aclp->acl_cnt == 0"));
853 	KASSERT(parent_aclp->acl_cnt <= ACL_MAX_ENTRIES,
854 	    ("parent_aclp->acl_cnt <= ACL_MAX_ENTRIES"));
855 
856 	/*
857 	 * NFSv4 Minor Version 1, draft-ietf-nfsv4-minorversion1-03.txt
858 	 *
859 	 * 3.16.6.2. Applying the mode given to CREATE or OPEN
860 	 *           to an inherited ACL
861 	 */
862 
863 	/*
864 	 * 1. Form an ACL that is the concatenation of all inheritable ACEs.
865 	 */
866 	for (i = 0; i < parent_aclp->acl_cnt; i++) {
867 		parent_entry = &(parent_aclp->acl_entry[i]);
868 		flags = parent_entry->ae_flags;
869 
870 		/*
871 		 * Entry is not inheritable at all.
872 		 */
873 		if ((flags & (ACL_ENTRY_DIRECTORY_INHERIT |
874 		    ACL_ENTRY_FILE_INHERIT)) == 0)
875 			continue;
876 
877 		/*
878 		 * We're creating a file, but entry is not inheritable
879 		 * by files.
880 		 */
881 		if (!is_directory && (flags & ACL_ENTRY_FILE_INHERIT) == 0)
882 			continue;
883 
884 		/*
885 		 * Entry is inheritable only by files, but has NO_PROPAGATE
886 		 * flag set, and we're creating a directory, so it wouldn't
887 		 * propagate to any file in that directory anyway.
888 		 */
889 		if (is_directory &&
890 		    (flags & ACL_ENTRY_DIRECTORY_INHERIT) == 0 &&
891 		    (flags & ACL_ENTRY_NO_PROPAGATE_INHERIT))
892 			continue;
893 
894 		KASSERT(child_aclp->acl_cnt + 1 <= ACL_MAX_ENTRIES,
895 		    ("child_aclp->acl_cnt + 1 <= ACL_MAX_ENTRIES"));
896 		child_aclp->acl_entry[child_aclp->acl_cnt] = *parent_entry;
897 		child_aclp->acl_cnt++;
898 	}
899 
900 	/*
901 	 * 2. For each entry in the new ACL, adjust its flags, possibly
902 	 *    creating two entries in place of one.
903 	 */
904 	for (i = 0; i < child_aclp->acl_cnt; i++) {
905 		entry = &(child_aclp->acl_entry[i]);
906 
907 		/*
908 		 * This is not in the specification, but SunOS
909 		 * apparently does that.
910 		 */
911 		if (((entry->ae_flags & ACL_ENTRY_NO_PROPAGATE_INHERIT) ||
912 		    !is_directory) &&
913 		    entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
914 			entry->ae_perm &= ~(ACL_WRITE_ACL | ACL_WRITE_OWNER);
915 
916 		/*
917 		 * 2.A. If the ACL_ENTRY_NO_PROPAGATE_INHERIT is set, or if the object
918 		 *      being created is not a directory, then clear the
919 		 *      following flags: ACL_ENTRY_NO_PROPAGATE_INHERIT,
920 		 *      ACL_ENTRY_FILE_INHERIT, ACL_ENTRY_DIRECTORY_INHERIT,
921 		 *      ACL_ENTRY_INHERIT_ONLY.
922 		 */
923 		if (entry->ae_flags & ACL_ENTRY_NO_PROPAGATE_INHERIT ||
924 		    !is_directory) {
925 			entry->ae_flags &= ~(ACL_ENTRY_NO_PROPAGATE_INHERIT |
926 			ACL_ENTRY_FILE_INHERIT | ACL_ENTRY_DIRECTORY_INHERIT |
927 			ACL_ENTRY_INHERIT_ONLY);
928 
929 			/*
930 			 * Continue on to the next ACE.
931 			 */
932 			continue;
933 		}
934 
935 		/*
936 		 * 2.B. If the object is a directory and ACL_ENTRY_FILE_INHERIT
937 		 *      is set, but ACL_ENTRY_NO_PROPAGATE_INHERIT is not set, ensure
938 		 *      that ACL_ENTRY_INHERIT_ONLY is set.  Continue to the
939 		 *      next ACE.  Otherwise...
940 		 */
941 		/*
942 		 * XXX: Read it again and make sure what does the "otherwise"
943 		 *      apply to.
944 		 */
945 		if (is_directory &&
946 		    (entry->ae_flags & ACL_ENTRY_FILE_INHERIT) &&
947 		    ((entry->ae_flags & ACL_ENTRY_DIRECTORY_INHERIT) == 0)) {
948 			entry->ae_flags |= ACL_ENTRY_INHERIT_ONLY;
949 			continue;
950 		}
951 
952 		/*
953 		 * 2.C. If the type of the ACE is neither ALLOW nor deny,
954 		 *      then continue.
955 		 */
956 		if (entry->ae_entry_type != ACL_ENTRY_TYPE_ALLOW &&
957 		    entry->ae_entry_type != ACL_ENTRY_TYPE_DENY)
958 			continue;
959 
960 		/*
961 		 * 2.D. Copy the original ACE into a second, adjacent ACE.
962 		 */
963 		copy = _acl_duplicate_entry(child_aclp, i);
964 
965 		/*
966 		 * 2.E. On the first ACE, ensure that ACL_ENTRY_INHERIT_ONLY
967 		 *      is set.
968 		 */
969 		entry->ae_flags |= ACL_ENTRY_INHERIT_ONLY;
970 
971 		/*
972 		 * 2.F. On the second ACE, clear the following flags:
973 		 *      ACL_ENTRY_NO_PROPAGATE_INHERIT, ACL_ENTRY_FILE_INHERIT,
974 		 *      ACL_ENTRY_DIRECTORY_INHERIT, ACL_ENTRY_INHERIT_ONLY.
975 		 */
976 		copy->ae_flags &= ~(ACL_ENTRY_NO_PROPAGATE_INHERIT |
977 		    ACL_ENTRY_FILE_INHERIT | ACL_ENTRY_DIRECTORY_INHERIT |
978 		    ACL_ENTRY_INHERIT_ONLY);
979 
980 		/*
981 		 * 2.G. On the second ACE, if the type is ALLOW,
982 		 *      an implementation MAY clear the following
983 		 *      mask bits: ACL_WRITE_ACL, ACL_WRITE_OWNER.
984 		 */
985 		if (copy->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
986 			copy->ae_perm &= ~(ACL_WRITE_ACL | ACL_WRITE_OWNER);
987 
988 		/*
989 		 * Increment the counter to skip the copied entry.
990 		 */
991 		i++;
992 	}
993 
994 	/*
995 	 * 3. To ensure that the mode is honored, apply the algorithm describe
996 	 *    in Section 2.16.6.3, using the mode that is to be used for file
997 	 *    creation.
998 	 */
999 	acl_nfs4_sync_acl_from_mode(child_aclp, mode, file_owner_id);
1000 }
1001 #endif /* _KERNEL */
1002 
1003 /*
1004  * Populate the ACL with entries inherited from parent_aclp.
1005  */
1006 static void
1007 acl_nfs4_inherit_entries(const struct acl *parent_aclp,
1008     struct acl *child_aclp, mode_t mode, int file_owner_id,
1009     int is_directory)
1010 {
1011 	int i, flags, tag;
1012 	const struct acl_entry *parent_entry;
1013 	struct acl_entry *entry;
1014 
1015 	KASSERT(parent_aclp->acl_cnt <= ACL_MAX_ENTRIES,
1016 	    ("parent_aclp->acl_cnt <= ACL_MAX_ENTRIES"));
1017 
1018 	for (i = 0; i < parent_aclp->acl_cnt; i++) {
1019 		parent_entry = &(parent_aclp->acl_entry[i]);
1020 		flags = parent_entry->ae_flags;
1021 		tag = parent_entry->ae_tag;
1022 
1023 		/*
1024 		 * Don't inherit owner@, group@, or everyone@ entries.
1025 		 */
1026 		if (tag == ACL_USER_OBJ || tag == ACL_GROUP_OBJ ||
1027 		    tag == ACL_EVERYONE)
1028 			continue;
1029 
1030 		/*
1031 		 * Entry is not inheritable at all.
1032 		 */
1033 		if ((flags & (ACL_ENTRY_DIRECTORY_INHERIT |
1034 		    ACL_ENTRY_FILE_INHERIT)) == 0)
1035 			continue;
1036 
1037 		/*
1038 		 * We're creating a file, but entry is not inheritable
1039 		 * by files.
1040 		 */
1041 		if (!is_directory && (flags & ACL_ENTRY_FILE_INHERIT) == 0)
1042 			continue;
1043 
1044 		/*
1045 		 * Entry is inheritable only by files, but has NO_PROPAGATE
1046 		 * flag set, and we're creating a directory, so it wouldn't
1047 		 * propagate to any file in that directory anyway.
1048 		 */
1049 		if (is_directory &&
1050 		    (flags & ACL_ENTRY_DIRECTORY_INHERIT) == 0 &&
1051 		    (flags & ACL_ENTRY_NO_PROPAGATE_INHERIT))
1052 			continue;
1053 
1054 		/*
1055 		 * Entry qualifies for being inherited.
1056 		 */
1057 		KASSERT(child_aclp->acl_cnt + 1 <= ACL_MAX_ENTRIES,
1058 		    ("child_aclp->acl_cnt + 1 <= ACL_MAX_ENTRIES"));
1059 		entry = &(child_aclp->acl_entry[child_aclp->acl_cnt]);
1060 		*entry = *parent_entry;
1061 		child_aclp->acl_cnt++;
1062 
1063 		entry->ae_flags &= ~ACL_ENTRY_INHERIT_ONLY;
1064 		entry->ae_flags |= ACL_ENTRY_INHERITED;
1065 
1066 		/*
1067 		 * If the type of the ACE is neither ALLOW nor DENY,
1068 		 * then leave it as it is and proceed to the next one.
1069 		 */
1070 		if (entry->ae_entry_type != ACL_ENTRY_TYPE_ALLOW &&
1071 		    entry->ae_entry_type != ACL_ENTRY_TYPE_DENY)
1072 			continue;
1073 
1074 		/*
1075 		 * If the ACL_ENTRY_NO_PROPAGATE_INHERIT is set, or if
1076 		 * the object being created is not a directory, then clear
1077 		 * the following flags: ACL_ENTRY_NO_PROPAGATE_INHERIT,
1078 		 * ACL_ENTRY_FILE_INHERIT, ACL_ENTRY_DIRECTORY_INHERIT,
1079 		 * ACL_ENTRY_INHERIT_ONLY.
1080 		 */
1081 		if (entry->ae_flags & ACL_ENTRY_NO_PROPAGATE_INHERIT ||
1082 		    !is_directory) {
1083 			entry->ae_flags &= ~(ACL_ENTRY_NO_PROPAGATE_INHERIT |
1084 			ACL_ENTRY_FILE_INHERIT | ACL_ENTRY_DIRECTORY_INHERIT |
1085 			ACL_ENTRY_INHERIT_ONLY);
1086 		}
1087 
1088 		/*
1089 		 * If the object is a directory and ACL_ENTRY_FILE_INHERIT
1090 		 * is set, but ACL_ENTRY_DIRECTORY_INHERIT is not set, ensure
1091 		 * that ACL_ENTRY_INHERIT_ONLY is set.
1092 		 */
1093 		if (is_directory &&
1094 		    (entry->ae_flags & ACL_ENTRY_FILE_INHERIT) &&
1095 		    ((entry->ae_flags & ACL_ENTRY_DIRECTORY_INHERIT) == 0)) {
1096 			entry->ae_flags |= ACL_ENTRY_INHERIT_ONLY;
1097 		}
1098 
1099 		if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW &&
1100 		    (entry->ae_flags & ACL_ENTRY_INHERIT_ONLY) == 0) {
1101 			/*
1102 			 * Some permissions must never be inherited.
1103 			 */
1104 			entry->ae_perm &= ~(ACL_WRITE_ACL | ACL_WRITE_OWNER |
1105 			    ACL_WRITE_NAMED_ATTRS | ACL_WRITE_ATTRIBUTES);
1106 
1107 			/*
1108 			 * Others must be masked according to the file mode.
1109 			 */
1110 			if ((mode & S_IRGRP) == 0)
1111 				entry->ae_perm &= ~ACL_READ_DATA;
1112 			if ((mode & S_IWGRP) == 0)
1113 				entry->ae_perm &=
1114 				    ~(ACL_WRITE_DATA | ACL_APPEND_DATA);
1115 			if ((mode & S_IXGRP) == 0)
1116 				entry->ae_perm &= ~ACL_EXECUTE;
1117 		}
1118 	}
1119 }
1120 
1121 /*
1122  * Calculate inherited ACL in a manner compatible with PSARC/2010/029.
1123  * It's also being used to calculate a trivial ACL, by inheriting from
1124  * a NULL ACL.
1125  */
1126 static void
1127 acl_nfs4_compute_inherited_acl_psarc(const struct acl *parent_aclp,
1128     struct acl *aclp, mode_t mode, int file_owner_id, int is_directory)
1129 {
1130 	acl_perm_t user_allow_first = 0, user_deny = 0, group_deny = 0;
1131 	acl_perm_t user_allow, group_allow, everyone_allow;
1132 
1133 	KASSERT(aclp->acl_cnt == 0, ("aclp->acl_cnt == 0"));
1134 
1135 	user_allow = group_allow = everyone_allow = ACL_READ_ACL |
1136 	    ACL_READ_ATTRIBUTES | ACL_READ_NAMED_ATTRS | ACL_SYNCHRONIZE;
1137 	user_allow |= ACL_WRITE_ACL | ACL_WRITE_OWNER | ACL_WRITE_ATTRIBUTES |
1138 	    ACL_WRITE_NAMED_ATTRS;
1139 
1140 	if (mode & S_IRUSR)
1141 		user_allow |= ACL_READ_DATA;
1142 	if (mode & S_IWUSR)
1143 		user_allow |= (ACL_WRITE_DATA | ACL_APPEND_DATA);
1144 	if (mode & S_IXUSR)
1145 		user_allow |= ACL_EXECUTE;
1146 
1147 	if (mode & S_IRGRP)
1148 		group_allow |= ACL_READ_DATA;
1149 	if (mode & S_IWGRP)
1150 		group_allow |= (ACL_WRITE_DATA | ACL_APPEND_DATA);
1151 	if (mode & S_IXGRP)
1152 		group_allow |= ACL_EXECUTE;
1153 
1154 	if (mode & S_IROTH)
1155 		everyone_allow |= ACL_READ_DATA;
1156 	if (mode & S_IWOTH)
1157 		everyone_allow |= (ACL_WRITE_DATA | ACL_APPEND_DATA);
1158 	if (mode & S_IXOTH)
1159 		everyone_allow |= ACL_EXECUTE;
1160 
1161 	user_deny = ((group_allow | everyone_allow) & ~user_allow);
1162 	group_deny = everyone_allow & ~group_allow;
1163 	user_allow_first = group_deny & ~user_deny;
1164 
1165 	if (user_allow_first != 0)
1166 		_acl_append(aclp, ACL_USER_OBJ, user_allow_first,
1167 		    ACL_ENTRY_TYPE_ALLOW);
1168 	if (user_deny != 0)
1169 		_acl_append(aclp, ACL_USER_OBJ, user_deny,
1170 		    ACL_ENTRY_TYPE_DENY);
1171 	if (group_deny != 0)
1172 		_acl_append(aclp, ACL_GROUP_OBJ, group_deny,
1173 		    ACL_ENTRY_TYPE_DENY);
1174 
1175 	if (parent_aclp != NULL)
1176 		acl_nfs4_inherit_entries(parent_aclp, aclp, mode,
1177 		    file_owner_id, is_directory);
1178 
1179 	_acl_append(aclp, ACL_USER_OBJ, user_allow, ACL_ENTRY_TYPE_ALLOW);
1180 	_acl_append(aclp, ACL_GROUP_OBJ, group_allow, ACL_ENTRY_TYPE_ALLOW);
1181 	_acl_append(aclp, ACL_EVERYONE, everyone_allow, ACL_ENTRY_TYPE_ALLOW);
1182 }
1183 
1184 #ifdef _KERNEL
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 #endif /* _KERNEL */
1199 
1200 /*
1201  * Calculate trivial ACL in a manner compatible with PSARC/2010/029.
1202  * Note that this results in an ACL different from (but semantically
1203  * equal to) the "canonical six" trivial ACL computed using algorithm
1204  * described in draft-ietf-nfsv4-minorversion1-03.txt, 3.16.6.2.
1205  */
1206 static void
1207 acl_nfs4_trivial_from_mode(struct acl *aclp, mode_t mode)
1208 {
1209 
1210 	aclp->acl_cnt = 0;
1211 	acl_nfs4_compute_inherited_acl_psarc(NULL, aclp, mode, -1, -1);
1212 }
1213 
1214 #ifndef _KERNEL
1215 /*
1216  * This routine is used by libc to implement acl_strip_np(3)
1217  * and acl_is_trivial_np(3).
1218  */
1219 void
1220 acl_nfs4_trivial_from_mode_libc(struct acl *aclp, int mode, int canonical_six)
1221 {
1222 
1223 	aclp->acl_cnt = 0;
1224 	if (canonical_six)
1225 		acl_nfs4_sync_acl_from_mode_draft(aclp, mode, -1);
1226 	else
1227 		acl_nfs4_trivial_from_mode(aclp, mode);
1228 }
1229 #endif /* !_KERNEL */
1230 
1231 #ifdef _KERNEL
1232 static int
1233 _acls_are_equal(const struct acl *a, const struct acl *b)
1234 {
1235 	int i;
1236 	const struct acl_entry *entrya, *entryb;
1237 
1238 	if (a->acl_cnt != b->acl_cnt)
1239 		return (0);
1240 
1241 	for (i = 0; i < b->acl_cnt; i++) {
1242 		entrya = &(a->acl_entry[i]);
1243 		entryb = &(b->acl_entry[i]);
1244 
1245 		if (entrya->ae_tag != entryb->ae_tag ||
1246 		    entrya->ae_id != entryb->ae_id ||
1247 		    entrya->ae_perm != entryb->ae_perm ||
1248 		    entrya->ae_entry_type != entryb->ae_entry_type ||
1249 		    entrya->ae_flags != entryb->ae_flags)
1250 			return (0);
1251 	}
1252 
1253 	return (1);
1254 }
1255 
1256 /*
1257  * This routine is used to determine whether to remove extended attribute
1258  * that stores ACL contents.
1259  */
1260 int
1261 acl_nfs4_is_trivial(const struct acl *aclp, int file_owner_id)
1262 {
1263 	int trivial;
1264 	mode_t tmpmode = 0;
1265 	struct acl *tmpaclp;
1266 
1267 	if (aclp->acl_cnt > 6)
1268 		return (0);
1269 
1270 	/*
1271 	 * Compute the mode from the ACL, then compute new ACL from that mode.
1272 	 * If the ACLs are identical, then the ACL is trivial.
1273 	 *
1274 	 * XXX: I guess there is a faster way to do this.  However, even
1275 	 *      this slow implementation significantly speeds things up
1276 	 *      for files that don't have non-trivial ACLs - it's critical
1277 	 *      for performance to not use EA when they are not needed.
1278 	 *
1279 	 * First try the PSARC/2010/029 semantics.
1280 	 */
1281 	tmpaclp = acl_alloc(M_WAITOK | M_ZERO);
1282 	acl_nfs4_sync_mode_from_acl(&tmpmode, aclp);
1283 	acl_nfs4_trivial_from_mode(tmpaclp, tmpmode);
1284 	trivial = _acls_are_equal(aclp, tmpaclp);
1285 	if (trivial) {
1286 		acl_free(tmpaclp);
1287 		return (trivial);
1288 	}
1289 
1290 	/*
1291 	 * Check if it's a draft-ietf-nfsv4-minorversion1-03.txt trivial ACL.
1292 	 */
1293 	tmpaclp->acl_cnt = 0;
1294 	acl_nfs4_sync_acl_from_mode_draft(tmpaclp, tmpmode, file_owner_id);
1295 	trivial = _acls_are_equal(aclp, tmpaclp);
1296 	acl_free(tmpaclp);
1297 
1298 	return (trivial);
1299 }
1300 #endif /* _KERNEL */
1301 
1302 int
1303 acl_nfs4_check(const struct acl *aclp, int is_directory)
1304 {
1305 	int i;
1306 	const struct acl_entry *entry;
1307 
1308 	/*
1309 	 * The spec doesn't seem to say anything about ACL validity.
1310 	 * It seems there is not much to do here.  There is even no need
1311 	 * to count "owner@" or "everyone@" (ACL_USER_OBJ and ACL_EVERYONE)
1312 	 * entries, as there can be several of them and that's perfectly
1313 	 * valid.  There can be none of them too.  Really.
1314 	 */
1315 
1316 	if (aclp->acl_cnt > ACL_MAX_ENTRIES || aclp->acl_cnt <= 0)
1317 		return (EINVAL);
1318 
1319 	for (i = 0; i < aclp->acl_cnt; i++) {
1320 		entry = &(aclp->acl_entry[i]);
1321 
1322 		switch (entry->ae_tag) {
1323 		case ACL_USER_OBJ:
1324 		case ACL_GROUP_OBJ:
1325 		case ACL_EVERYONE:
1326 			if (entry->ae_id != ACL_UNDEFINED_ID)
1327 				return (EINVAL);
1328 			break;
1329 
1330 		case ACL_USER:
1331 		case ACL_GROUP:
1332 			if (entry->ae_id == ACL_UNDEFINED_ID)
1333 				return (EINVAL);
1334 			break;
1335 
1336 		default:
1337 			return (EINVAL);
1338 		}
1339 
1340 		if ((entry->ae_perm | ACL_NFS4_PERM_BITS) != ACL_NFS4_PERM_BITS)
1341 			return (EINVAL);
1342 
1343 		/*
1344 		 * Disallow ACL_ENTRY_TYPE_AUDIT and ACL_ENTRY_TYPE_ALARM for now.
1345 		 */
1346 		if (entry->ae_entry_type != ACL_ENTRY_TYPE_ALLOW &&
1347 		    entry->ae_entry_type != ACL_ENTRY_TYPE_DENY)
1348 			return (EINVAL);
1349 
1350 		if ((entry->ae_flags | ACL_FLAGS_BITS) != ACL_FLAGS_BITS)
1351 			return (EINVAL);
1352 
1353 		/* Disallow unimplemented flags. */
1354 		if (entry->ae_flags & (ACL_ENTRY_SUCCESSFUL_ACCESS |
1355 		    ACL_ENTRY_FAILED_ACCESS))
1356 			return (EINVAL);
1357 
1358 		/* Disallow flags not allowed for ordinary files. */
1359 		if (!is_directory) {
1360 			if (entry->ae_flags & (ACL_ENTRY_FILE_INHERIT |
1361 			    ACL_ENTRY_DIRECTORY_INHERIT |
1362 			    ACL_ENTRY_NO_PROPAGATE_INHERIT | ACL_ENTRY_INHERIT_ONLY))
1363 				return (EINVAL);
1364 		}
1365 	}
1366 
1367 	return (0);
1368 }
1369 
1370 #ifdef	_KERNEL
1371 static int
1372 acl_nfs4_modload(module_t module, int what, void *arg)
1373 {
1374 	int ret;
1375 
1376 	ret = 0;
1377 
1378 	switch (what) {
1379 	case MOD_LOAD:
1380 	case MOD_SHUTDOWN:
1381 		break;
1382 
1383 	case MOD_QUIESCE:
1384 		/* XXX TODO */
1385 		ret = 0;
1386 		break;
1387 
1388 	case MOD_UNLOAD:
1389 		/* XXX TODO */
1390 		ret = 0;
1391 		break;
1392 	default:
1393 		ret = EINVAL;
1394 		break;
1395 	}
1396 
1397 	return (ret);
1398 }
1399 
1400 static moduledata_t acl_nfs4_mod = {
1401 	"acl_nfs4",
1402 	acl_nfs4_modload,
1403 	NULL
1404 };
1405 
1406 /*
1407  * XXX TODO: which subsystem, order?
1408  */
1409 DECLARE_MODULE(acl_nfs4, acl_nfs4_mod, SI_SUB_VFS, SI_ORDER_FIRST);
1410 MODULE_VERSION(acl_nfs4, 1);
1411 #endif	/* _KERNEL */
1412