xref: /freebsd/sys/kern/subr_acl_nfs4.c (revision 675be9115aae86ad6b3d877155d4fd7822892105)
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 #endif /* !_KERNEL */
55 
56 #ifdef _KERNEL
57 
58 static void	acl_nfs4_trivial_from_mode(struct acl *aclp, mode_t mode);
59 
60 static int	acl_nfs4_old_semantics = 0;
61 
62 SYSCTL_INT(_vfs, OID_AUTO, acl_nfs4_old_semantics, CTLFLAG_RW,
63     &acl_nfs4_old_semantics, 0, "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 <= ACL_MAX_ENTRIES,
118 	    ("aclp->acl_cnt <= ACL_MAX_ENTRIES"));
119 
120 	for (i = 0; i < aclp->acl_cnt; i++) {
121 		entry = &(aclp->acl_entry[i]);
122 
123 		if (entry->ae_entry_type != ACL_ENTRY_TYPE_ALLOW &&
124 		    entry->ae_entry_type != ACL_ENTRY_TYPE_DENY)
125 			continue;
126 		if (entry->ae_flags & ACL_ENTRY_INHERIT_ONLY)
127 			continue;
128 		switch (entry->ae_tag) {
129 		case ACL_USER_OBJ:
130 			if (file_uid != cred->cr_uid)
131 				continue;
132 			break;
133 		case ACL_USER:
134 			if (entry->ae_id != cred->cr_uid)
135 				continue;
136 			break;
137 		case ACL_GROUP_OBJ:
138 			if (!groupmember(file_gid, cred))
139 				continue;
140 			break;
141 		case ACL_GROUP:
142 			if (!groupmember(entry->ae_id, cred))
143 				continue;
144 			break;
145 		default:
146 			KASSERT(entry->ae_tag == ACL_EVERYONE,
147 			    ("entry->ae_tag == ACL_EVERYONE"));
148 		}
149 
150 		if (entry->ae_entry_type == ACL_ENTRY_TYPE_DENY) {
151 			if (entry->ae_perm & access_mask) {
152 				if (denied_explicitly != NULL)
153 					*denied_explicitly = 1;
154 				return (1);
155 			}
156 		}
157 
158 		access_mask &= ~(entry->ae_perm);
159 		if (access_mask == 0)
160 			return (0);
161 	}
162 
163 	return (1);
164 }
165 
166 int
167 vaccess_acl_nfs4(enum vtype type, uid_t file_uid, gid_t file_gid,
168     struct acl *aclp, accmode_t accmode, struct ucred *cred, int *privused)
169 {
170 	accmode_t priv_granted = 0;
171 	int denied, explicitly_denied, access_mask, is_directory,
172 	    must_be_owner = 0;
173 	mode_t file_mode = 0;
174 
175 	KASSERT((accmode & ~(VEXEC | VWRITE | VREAD | VADMIN | VAPPEND |
176 	    VEXPLICIT_DENY | VREAD_NAMED_ATTRS | VWRITE_NAMED_ATTRS |
177 	    VDELETE_CHILD | VREAD_ATTRIBUTES | VWRITE_ATTRIBUTES | VDELETE |
178 	    VREAD_ACL | VWRITE_ACL | VWRITE_OWNER | VSYNCHRONIZE)) == 0,
179 	    ("invalid bit in accmode"));
180 	KASSERT((accmode & VAPPEND) == 0 || (accmode & VWRITE),
181 	    	("VAPPEND without VWRITE"));
182 
183 	if (privused != NULL)
184 		*privused = 0;
185 
186 	if (accmode & VADMIN)
187 		must_be_owner = 1;
188 
189 	/*
190 	 * Ignore VSYNCHRONIZE permission.
191 	 */
192 	accmode &= ~VSYNCHRONIZE;
193 
194 	access_mask = _access_mask_from_accmode(accmode);
195 
196 	if (type == VDIR)
197 		is_directory = 1;
198 	else
199 		is_directory = 0;
200 
201 	/*
202 	 * File owner is always allowed to read and write the ACL
203 	 * and basic attributes.  This is to prevent a situation
204 	 * where user would change ACL in a way that prevents him
205 	 * from undoing the change.
206 	 */
207 	if (file_uid == cred->cr_uid)
208 		access_mask &= ~(ACL_READ_ACL | ACL_WRITE_ACL |
209 		    ACL_READ_ATTRIBUTES | ACL_WRITE_ATTRIBUTES);
210 
211 	/*
212 	 * Ignore append permission for regular files; use write
213 	 * permission instead.
214 	 */
215 	if (!is_directory && (access_mask & ACL_APPEND_DATA)) {
216 		access_mask &= ~ACL_APPEND_DATA;
217 		access_mask |= ACL_WRITE_DATA;
218 	}
219 
220 	denied = _acl_denies(aclp, access_mask, cred, file_uid, file_gid,
221 	    &explicitly_denied);
222 
223 	if (must_be_owner) {
224 		if (file_uid != cred->cr_uid)
225 			denied = EPERM;
226 	}
227 
228 	/*
229 	 * For VEXEC, ensure that at least one execute bit is set for
230 	 * non-directories. We have to check the mode here to stay
231 	 * consistent with execve(2). See the test in
232 	 * exec_check_permissions().
233 	 */
234 	acl_nfs4_sync_mode_from_acl(&file_mode, aclp);
235 	if (!denied && !is_directory && (accmode & VEXEC) &&
236 	    (file_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) == 0)
237 		denied = EACCES;
238 
239 	if (!denied)
240 		return (0);
241 
242 	/*
243 	 * Access failed.  Iff it was not denied explicitly and
244 	 * VEXPLICIT_DENY flag was specified, allow access.
245 	 */
246 	if ((accmode & VEXPLICIT_DENY) && explicitly_denied == 0)
247 		return (0);
248 
249 	accmode &= ~VEXPLICIT_DENY;
250 
251 	/*
252 	 * No match.  Try to use privileges, if there are any.
253 	 */
254 	if (is_directory) {
255 		if ((accmode & VEXEC) && !priv_check_cred(cred,
256 		    PRIV_VFS_LOOKUP, 0))
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, 0))
267 			priv_granted |= VEXEC;
268 	}
269 
270 	if ((accmode & VREAD) && !priv_check_cred(cred, PRIV_VFS_READ, 0))
271 		priv_granted |= VREAD;
272 
273 	if ((accmode & (VWRITE | VAPPEND | VDELETE_CHILD)) &&
274 	    !priv_check_cred(cred, PRIV_VFS_WRITE, 0))
275 		priv_granted |= (VWRITE | VAPPEND | VDELETE_CHILD);
276 
277 	if ((accmode & VADMIN_PERMS) &&
278 	    !priv_check_cred(cred, PRIV_VFS_ADMIN, 0))
279 		priv_granted |= VADMIN_PERMS;
280 
281 	if ((accmode & VSTAT_PERMS) &&
282 	    !priv_check_cred(cred, PRIV_VFS_STAT, 0))
283 		priv_granted |= VSTAT_PERMS;
284 
285 	if ((accmode & priv_granted) == accmode) {
286 		if (privused != NULL)
287 			*privused = 1;
288 
289 		return (0);
290 	}
291 
292 	if (accmode & (VADMIN_PERMS | VDELETE_CHILD | VDELETE))
293 		denied = EPERM;
294 	else
295 		denied = EACCES;
296 
297 	return (denied);
298 }
299 #endif /* _KERNEL */
300 
301 static int
302 _acl_entry_matches(struct acl_entry *entry, acl_tag_t tag, acl_perm_t perm,
303     acl_entry_type_t entry_type)
304 {
305 	if (entry->ae_tag != tag)
306 		return (0);
307 
308 	if (entry->ae_id != ACL_UNDEFINED_ID)
309 		return (0);
310 
311 	if (entry->ae_perm != perm)
312 		return (0);
313 
314 	if (entry->ae_entry_type != entry_type)
315 		return (0);
316 
317 	if (entry->ae_flags != 0)
318 		return (0);
319 
320 	return (1);
321 }
322 
323 static struct acl_entry *
324 _acl_append(struct acl *aclp, acl_tag_t tag, acl_perm_t perm,
325     acl_entry_type_t entry_type)
326 {
327 	struct acl_entry *entry;
328 
329 	KASSERT(aclp->acl_cnt + 1 <= ACL_MAX_ENTRIES,
330 	    ("aclp->acl_cnt + 1 <= ACL_MAX_ENTRIES"));
331 
332 	entry = &(aclp->acl_entry[aclp->acl_cnt]);
333 	aclp->acl_cnt++;
334 
335 	entry->ae_tag = tag;
336 	entry->ae_id = ACL_UNDEFINED_ID;
337 	entry->ae_perm = perm;
338 	entry->ae_entry_type = entry_type;
339 	entry->ae_flags = 0;
340 
341 	return (entry);
342 }
343 
344 static struct acl_entry *
345 _acl_duplicate_entry(struct acl *aclp, int entry_index)
346 {
347 	int i;
348 
349 	KASSERT(aclp->acl_cnt + 1 <= ACL_MAX_ENTRIES,
350 	    ("aclp->acl_cnt + 1 <= ACL_MAX_ENTRIES"));
351 
352 	for (i = aclp->acl_cnt; i > entry_index; i--)
353 		aclp->acl_entry[i] = aclp->acl_entry[i - 1];
354 
355 	aclp->acl_cnt++;
356 
357 	return (&(aclp->acl_entry[entry_index + 1]));
358 }
359 
360 static void
361 acl_nfs4_sync_acl_from_mode_draft(struct acl *aclp, mode_t mode,
362     int file_owner_id)
363 {
364 	int i, meets, must_append;
365 	struct acl_entry *entry, *copy, *previous,
366 	    *a1, *a2, *a3, *a4, *a5, *a6;
367 	mode_t amode;
368 	const int READ = 04;
369 	const int WRITE = 02;
370 	const int EXEC = 01;
371 
372 	KASSERT(aclp->acl_cnt <= ACL_MAX_ENTRIES,
373 	    ("aclp->acl_cnt <= ACL_MAX_ENTRIES"));
374 
375 	/*
376 	 * NFSv4 Minor Version 1, draft-ietf-nfsv4-minorversion1-03.txt
377 	 *
378 	 * 3.16.6.3. Applying a Mode to an Existing ACL
379 	 */
380 
381 	/*
382 	 * 1. For each ACE:
383 	 */
384 	for (i = 0; i < aclp->acl_cnt; i++) {
385 		entry = &(aclp->acl_entry[i]);
386 
387 		/*
388 		 * 1.1. If the type is neither ALLOW or DENY - skip.
389 		 */
390 		if (entry->ae_entry_type != ACL_ENTRY_TYPE_ALLOW &&
391 		    entry->ae_entry_type != ACL_ENTRY_TYPE_DENY)
392 			continue;
393 
394 		/*
395 		 * 1.2. If ACL_ENTRY_INHERIT_ONLY is set - skip.
396 		 */
397 		if (entry->ae_flags & ACL_ENTRY_INHERIT_ONLY)
398 			continue;
399 
400 		/*
401 		 * 1.3. If ACL_ENTRY_FILE_INHERIT or ACL_ENTRY_DIRECTORY_INHERIT
402 		 *      are set:
403 		 */
404 		if (entry->ae_flags &
405 		    (ACL_ENTRY_FILE_INHERIT | ACL_ENTRY_DIRECTORY_INHERIT)) {
406 			/*
407 			 * 1.3.1. A copy of the current ACE is made, and placed
408 			 *        in the ACL immediately following the current
409 			 *        ACE.
410 			 */
411 			copy = _acl_duplicate_entry(aclp, i);
412 
413 			/*
414 			 * 1.3.2. In the first ACE, the flag
415 			 *        ACL_ENTRY_INHERIT_ONLY is set.
416 			 */
417 			entry->ae_flags |= ACL_ENTRY_INHERIT_ONLY;
418 
419 			/*
420 			 * 1.3.3. In the second ACE, the following flags
421 			 *        are cleared:
422 			 *        ACL_ENTRY_FILE_INHERIT,
423 			 *        ACL_ENTRY_DIRECTORY_INHERIT,
424 			 *        ACL_ENTRY_NO_PROPAGATE_INHERIT.
425 			 */
426 			copy->ae_flags &= ~(ACL_ENTRY_FILE_INHERIT |
427 			    ACL_ENTRY_DIRECTORY_INHERIT |
428 			    ACL_ENTRY_NO_PROPAGATE_INHERIT);
429 
430 			/*
431 			 * The algorithm continues on with the second ACE.
432 			 */
433 			i++;
434 			entry = copy;
435 		}
436 
437 		/*
438 		 * 1.4. If it's owner@, group@ or everyone@ entry, clear
439 		 *      ACL_READ_DATA, ACL_WRITE_DATA, ACL_APPEND_DATA
440 		 *      and ACL_EXECUTE.  Continue to the next entry.
441 		 */
442 		if (entry->ae_tag == ACL_USER_OBJ ||
443 		    entry->ae_tag == ACL_GROUP_OBJ ||
444 		    entry->ae_tag == ACL_EVERYONE) {
445 			entry->ae_perm &= ~(ACL_READ_DATA | ACL_WRITE_DATA |
446 			    ACL_APPEND_DATA | ACL_EXECUTE);
447 			continue;
448 		}
449 
450 		/*
451 		 * 1.5. Otherwise, if the "who" field did not match one
452 		 *      of OWNER@, GROUP@, EVERYONE@:
453 		 *
454 		 * 1.5.1. If the type is ALLOW, check the preceding ACE.
455 		 *        If it does not meet all of the following criteria:
456 		 */
457 		if (entry->ae_entry_type != ACL_ENTRY_TYPE_ALLOW)
458 			continue;
459 
460 		meets = 0;
461 		if (i > 0) {
462 			meets = 1;
463 			previous = &(aclp->acl_entry[i - 1]);
464 
465 			/*
466 			 * 1.5.1.1. The type field is DENY,
467 			 */
468 			if (previous->ae_entry_type != ACL_ENTRY_TYPE_DENY)
469 				meets = 0;
470 
471 			/*
472 			 * 1.5.1.2. The "who" field is the same as the current
473 			 *          ACE,
474 			 *
475 			 * 1.5.1.3. The flag bit ACE4_IDENTIFIER_GROUP
476 			 *          is the same as it is in the current ACE,
477 			 *          and no other flag bits are set,
478 			 */
479 			if (previous->ae_id != entry->ae_id ||
480 			    previous->ae_tag != entry->ae_tag)
481 				meets = 0;
482 
483 			if (previous->ae_flags)
484 				meets = 0;
485 
486 			/*
487 			 * 1.5.1.4. The mask bits are a subset of the mask bits
488 			 *          of the current ACE, and are also subset of
489 			 *          the following: ACL_READ_DATA,
490 			 *          ACL_WRITE_DATA, ACL_APPEND_DATA, ACL_EXECUTE
491 			 */
492 			if (previous->ae_perm & ~(entry->ae_perm))
493 				meets = 0;
494 
495 			if (previous->ae_perm & ~(ACL_READ_DATA |
496 			    ACL_WRITE_DATA | ACL_APPEND_DATA | ACL_EXECUTE))
497 				meets = 0;
498 		}
499 
500 		if (!meets) {
501 			/*
502 		 	 * Then the ACE of type DENY, with a who equal
503 			 * to the current ACE, flag bits equal to
504 			 * (<current ACE flags> & <ACE_IDENTIFIER_GROUP>)
505 			 * and no mask bits, is prepended.
506 			 */
507 			previous = entry;
508 			entry = _acl_duplicate_entry(aclp, i);
509 
510 			/* Adjust counter, as we've just added an entry. */
511 			i++;
512 
513 			previous->ae_tag = entry->ae_tag;
514 			previous->ae_id = entry->ae_id;
515 			previous->ae_flags = entry->ae_flags;
516 			previous->ae_perm = 0;
517 			previous->ae_entry_type = ACL_ENTRY_TYPE_DENY;
518 		}
519 
520 		/*
521 		 * 1.5.2. The following modifications are made to the prepended
522 		 *        ACE.  The intent is to mask the following ACE
523 		 *        to disallow ACL_READ_DATA, ACL_WRITE_DATA,
524 		 *        ACL_APPEND_DATA, or ACL_EXECUTE, based upon the group
525 		 *        permissions of the new mode.  As a special case,
526 		 *        if the ACE matches the current owner of the file,
527 		 *        the owner bits are used, rather than the group bits.
528 		 *        This is reflected in the algorithm below.
529 		 */
530 		amode = mode >> 3;
531 
532 		/*
533 		 * If ACE4_IDENTIFIER_GROUP is not set, and the "who" field
534 		 * in ACE matches the owner of the file, we shift amode three
535 		 * more bits, in order to have the owner permission bits
536 		 * placed in the three low order bits of amode.
537 		 */
538 		if (entry->ae_tag == ACL_USER && entry->ae_id == file_owner_id)
539 			amode = amode >> 3;
540 
541 		if (entry->ae_perm & ACL_READ_DATA) {
542 			if (amode & READ)
543 				previous->ae_perm &= ~ACL_READ_DATA;
544 			else
545 				previous->ae_perm |= ACL_READ_DATA;
546 		}
547 
548 		if (entry->ae_perm & ACL_WRITE_DATA) {
549 			if (amode & WRITE)
550 				previous->ae_perm &= ~ACL_WRITE_DATA;
551 			else
552 				previous->ae_perm |= ACL_WRITE_DATA;
553 		}
554 
555 		if (entry->ae_perm & ACL_APPEND_DATA) {
556 			if (amode & WRITE)
557 				previous->ae_perm &= ~ACL_APPEND_DATA;
558 			else
559 				previous->ae_perm |= ACL_APPEND_DATA;
560 		}
561 
562 		if (entry->ae_perm & ACL_EXECUTE) {
563 			if (amode & EXEC)
564 				previous->ae_perm &= ~ACL_EXECUTE;
565 			else
566 				previous->ae_perm |= ACL_EXECUTE;
567 		}
568 
569 		/*
570 		 * 1.5.3. If ACE4_IDENTIFIER_GROUP is set in the flags
571 		 *        of the ALLOW ace:
572 		 *
573 		 * XXX: This point is not there in the Falkner's draft.
574 		 */
575 		if (entry->ae_tag == ACL_GROUP &&
576 		    entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW) {
577 			mode_t extramode, ownermode;
578 			extramode = (mode >> 3) & 07;
579 			ownermode = mode >> 6;
580 			extramode &= ~ownermode;
581 
582 			if (extramode) {
583 				if (extramode & READ) {
584 					entry->ae_perm &= ~ACL_READ_DATA;
585 					previous->ae_perm &= ~ACL_READ_DATA;
586 				}
587 
588 				if (extramode & WRITE) {
589 					entry->ae_perm &=
590 					    ~(ACL_WRITE_DATA | ACL_APPEND_DATA);
591 					previous->ae_perm &=
592 					    ~(ACL_WRITE_DATA | ACL_APPEND_DATA);
593 				}
594 
595 				if (extramode & EXEC) {
596 					entry->ae_perm &= ~ACL_EXECUTE;
597 					previous->ae_perm &= ~ACL_EXECUTE;
598 				}
599 			}
600 		}
601 	}
602 
603 	/*
604 	 * 2. If there at least six ACEs, the final six ACEs are examined.
605 	 *    If they are not equal to what we want, append six ACEs.
606 	 */
607 	must_append = 0;
608 	if (aclp->acl_cnt < 6) {
609 		must_append = 1;
610 	} else {
611 		a6 = &(aclp->acl_entry[aclp->acl_cnt - 1]);
612 		a5 = &(aclp->acl_entry[aclp->acl_cnt - 2]);
613 		a4 = &(aclp->acl_entry[aclp->acl_cnt - 3]);
614 		a3 = &(aclp->acl_entry[aclp->acl_cnt - 4]);
615 		a2 = &(aclp->acl_entry[aclp->acl_cnt - 5]);
616 		a1 = &(aclp->acl_entry[aclp->acl_cnt - 6]);
617 
618 		if (!_acl_entry_matches(a1, ACL_USER_OBJ, 0,
619 		    ACL_ENTRY_TYPE_DENY))
620 			must_append = 1;
621 		if (!_acl_entry_matches(a2, ACL_USER_OBJ, ACL_WRITE_ACL |
622 		    ACL_WRITE_OWNER | ACL_WRITE_ATTRIBUTES |
623 		    ACL_WRITE_NAMED_ATTRS, ACL_ENTRY_TYPE_ALLOW))
624 			must_append = 1;
625 		if (!_acl_entry_matches(a3, ACL_GROUP_OBJ, 0,
626 		    ACL_ENTRY_TYPE_DENY))
627 			must_append = 1;
628 		if (!_acl_entry_matches(a4, ACL_GROUP_OBJ, 0,
629 		    ACL_ENTRY_TYPE_ALLOW))
630 			must_append = 1;
631 		if (!_acl_entry_matches(a5, ACL_EVERYONE, ACL_WRITE_ACL |
632 		    ACL_WRITE_OWNER | ACL_WRITE_ATTRIBUTES |
633 		    ACL_WRITE_NAMED_ATTRS, ACL_ENTRY_TYPE_DENY))
634 			must_append = 1;
635 		if (!_acl_entry_matches(a6, ACL_EVERYONE, ACL_READ_ACL |
636 		    ACL_READ_ATTRIBUTES | ACL_READ_NAMED_ATTRS |
637 		    ACL_SYNCHRONIZE, ACL_ENTRY_TYPE_ALLOW))
638 			must_append = 1;
639 	}
640 
641 	if (must_append) {
642 		KASSERT(aclp->acl_cnt + 6 <= ACL_MAX_ENTRIES,
643 		    ("aclp->acl_cnt <= ACL_MAX_ENTRIES"));
644 
645 		a1 = _acl_append(aclp, ACL_USER_OBJ, 0, ACL_ENTRY_TYPE_DENY);
646 		a2 = _acl_append(aclp, ACL_USER_OBJ, ACL_WRITE_ACL |
647 		    ACL_WRITE_OWNER | ACL_WRITE_ATTRIBUTES |
648 		    ACL_WRITE_NAMED_ATTRS, ACL_ENTRY_TYPE_ALLOW);
649 		a3 = _acl_append(aclp, ACL_GROUP_OBJ, 0, ACL_ENTRY_TYPE_DENY);
650 		a4 = _acl_append(aclp, ACL_GROUP_OBJ, 0, ACL_ENTRY_TYPE_ALLOW);
651 		a5 = _acl_append(aclp, ACL_EVERYONE, ACL_WRITE_ACL |
652 		    ACL_WRITE_OWNER | ACL_WRITE_ATTRIBUTES |
653 		    ACL_WRITE_NAMED_ATTRS, ACL_ENTRY_TYPE_DENY);
654 		a6 = _acl_append(aclp, ACL_EVERYONE, ACL_READ_ACL |
655 		    ACL_READ_ATTRIBUTES | ACL_READ_NAMED_ATTRS |
656 		    ACL_SYNCHRONIZE, ACL_ENTRY_TYPE_ALLOW);
657 
658 		KASSERT(a1 != NULL && a2 != NULL && a3 != NULL && a4 != NULL &&
659 		    a5 != NULL && a6 != NULL, ("couldn't append to ACL."));
660 	}
661 
662 	/*
663 	 * 3. The final six ACEs are adjusted according to the incoming mode.
664 	 */
665 	if (mode & S_IRUSR)
666 		a2->ae_perm |= ACL_READ_DATA;
667 	else
668 		a1->ae_perm |= ACL_READ_DATA;
669 	if (mode & S_IWUSR)
670 		a2->ae_perm |= (ACL_WRITE_DATA | ACL_APPEND_DATA);
671 	else
672 		a1->ae_perm |= (ACL_WRITE_DATA | ACL_APPEND_DATA);
673 	if (mode & S_IXUSR)
674 		a2->ae_perm |= ACL_EXECUTE;
675 	else
676 		a1->ae_perm |= ACL_EXECUTE;
677 
678 	if (mode & S_IRGRP)
679 		a4->ae_perm |= ACL_READ_DATA;
680 	else
681 		a3->ae_perm |= ACL_READ_DATA;
682 	if (mode & S_IWGRP)
683 		a4->ae_perm |= (ACL_WRITE_DATA | ACL_APPEND_DATA);
684 	else
685 		a3->ae_perm |= (ACL_WRITE_DATA | ACL_APPEND_DATA);
686 	if (mode & S_IXGRP)
687 		a4->ae_perm |= ACL_EXECUTE;
688 	else
689 		a3->ae_perm |= ACL_EXECUTE;
690 
691 	if (mode & S_IROTH)
692 		a6->ae_perm |= ACL_READ_DATA;
693 	else
694 		a5->ae_perm |= ACL_READ_DATA;
695 	if (mode & S_IWOTH)
696 		a6->ae_perm |= (ACL_WRITE_DATA | ACL_APPEND_DATA);
697 	else
698 		a5->ae_perm |= (ACL_WRITE_DATA | ACL_APPEND_DATA);
699 	if (mode & S_IXOTH)
700 		a6->ae_perm |= ACL_EXECUTE;
701 	else
702 		a5->ae_perm |= ACL_EXECUTE;
703 }
704 
705 #ifdef _KERNEL
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 #endif /* _KERNEL */
717 
718 void
719 acl_nfs4_sync_mode_from_acl(mode_t *_mode, const struct acl *aclp)
720 {
721 	int i;
722 	mode_t old_mode = *_mode, mode = 0, seen = 0;
723 	const struct acl_entry *entry;
724 
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 #ifdef _KERNEL
841 /*
842  * Calculate inherited ACL in a manner compatible with NFSv4 Minor Version 1,
843  * draft-ietf-nfsv4-minorversion1-03.txt.
844  */
845 static void
846 acl_nfs4_compute_inherited_acl_draft(const struct acl *parent_aclp,
847     struct acl *child_aclp, mode_t mode, int file_owner_id,
848     int is_directory)
849 {
850 	int i, flags;
851 	const struct acl_entry *parent_entry;
852 	struct acl_entry *entry, *copy;
853 
854 	KASSERT(child_aclp->acl_cnt == 0, ("child_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 #endif /* _KERNEL */
1004 
1005 /*
1006  * Populate the ACL with entries inherited from parent_aclp.
1007  */
1008 static void
1009 acl_nfs4_inherit_entries(const struct acl *parent_aclp,
1010     struct acl *child_aclp, mode_t mode, int file_owner_id,
1011     int is_directory)
1012 {
1013 	int i, flags, tag;
1014 	const struct acl_entry *parent_entry;
1015 	struct acl_entry *entry;
1016 
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 #ifdef _KERNEL
1186 void
1187 acl_nfs4_compute_inherited_acl(const struct acl *parent_aclp,
1188     struct acl *child_aclp, mode_t mode, int file_owner_id,
1189     int is_directory)
1190 {
1191 
1192 	if (acl_nfs4_old_semantics)
1193 		acl_nfs4_compute_inherited_acl_draft(parent_aclp, child_aclp,
1194 		    mode, file_owner_id, is_directory);
1195 	else
1196 		acl_nfs4_compute_inherited_acl_psarc(parent_aclp, child_aclp,
1197 		    mode, file_owner_id, is_directory);
1198 }
1199 #endif /* _KERNEL */
1200 
1201 /*
1202  * Calculate trivial ACL in a manner compatible with PSARC/2010/029.
1203  * Note that this results in an ACL different from (but semantically
1204  * equal to) the "canonical six" trivial ACL computed using algorithm
1205  * described in draft-ietf-nfsv4-minorversion1-03.txt, 3.16.6.2.
1206  */
1207 static void
1208 acl_nfs4_trivial_from_mode(struct acl *aclp, mode_t mode)
1209 {
1210 
1211 	aclp->acl_cnt = 0;
1212 	acl_nfs4_compute_inherited_acl_psarc(NULL, aclp, mode, -1, -1);
1213 }
1214 
1215 #ifndef _KERNEL
1216 /*
1217  * This routine is used by libc to implement acl_strip_np(3)
1218  * and acl_is_trivial_np(3).
1219  */
1220 void
1221 acl_nfs4_trivial_from_mode_libc(struct acl *aclp, int mode, int canonical_six)
1222 {
1223 
1224 	aclp->acl_cnt = 0;
1225 	if (canonical_six)
1226 		acl_nfs4_sync_acl_from_mode_draft(aclp, mode, -1);
1227 	else
1228 		acl_nfs4_trivial_from_mode(aclp, mode);
1229 }
1230 #endif /* !_KERNEL */
1231 
1232 #ifdef _KERNEL
1233 static int
1234 _acls_are_equal(const struct acl *a, const struct acl *b)
1235 {
1236 	int i;
1237 	const struct acl_entry *entrya, *entryb;
1238 
1239 	if (a->acl_cnt != b->acl_cnt)
1240 		return (0);
1241 
1242 	for (i = 0; i < b->acl_cnt; i++) {
1243 		entrya = &(a->acl_entry[i]);
1244 		entryb = &(b->acl_entry[i]);
1245 
1246 		if (entrya->ae_tag != entryb->ae_tag ||
1247 		    entrya->ae_id != entryb->ae_id ||
1248 		    entrya->ae_perm != entryb->ae_perm ||
1249 		    entrya->ae_entry_type != entryb->ae_entry_type ||
1250 		    entrya->ae_flags != entryb->ae_flags)
1251 			return (0);
1252 	}
1253 
1254 	return (1);
1255 }
1256 
1257 /*
1258  * This routine is used to determine whether to remove extended attribute
1259  * that stores ACL contents.
1260  */
1261 int
1262 acl_nfs4_is_trivial(const struct acl *aclp, int file_owner_id)
1263 {
1264 	int trivial;
1265 	mode_t tmpmode = 0;
1266 	struct acl *tmpaclp;
1267 
1268 	if (aclp->acl_cnt > 6)
1269 		return (0);
1270 
1271 	/*
1272 	 * Compute the mode from the ACL, then compute new ACL from that mode.
1273 	 * If the ACLs are identical, then the ACL is trivial.
1274 	 *
1275 	 * XXX: I guess there is a faster way to do this.  However, even
1276 	 *      this slow implementation significantly speeds things up
1277 	 *      for files that don't have non-trivial ACLs - it's critical
1278 	 *      for performance to not use EA when they are not needed.
1279 	 *
1280 	 * First try the PSARC/2010/029 semantics.
1281 	 */
1282 	tmpaclp = acl_alloc(M_WAITOK | M_ZERO);
1283 	acl_nfs4_sync_mode_from_acl(&tmpmode, aclp);
1284 	acl_nfs4_trivial_from_mode(tmpaclp, tmpmode);
1285 	trivial = _acls_are_equal(aclp, tmpaclp);
1286 	if (trivial) {
1287 		acl_free(tmpaclp);
1288 		return (trivial);
1289 	}
1290 
1291 	/*
1292 	 * Check if it's a draft-ietf-nfsv4-minorversion1-03.txt trivial ACL.
1293 	 */
1294 	tmpaclp->acl_cnt = 0;
1295 	acl_nfs4_sync_acl_from_mode_draft(tmpaclp, tmpmode, file_owner_id);
1296 	trivial = _acls_are_equal(aclp, tmpaclp);
1297 	acl_free(tmpaclp);
1298 
1299 	return (trivial);
1300 }
1301 #endif /* _KERNEL */
1302 
1303 int
1304 acl_nfs4_check(const struct acl *aclp, int is_directory)
1305 {
1306 	int i;
1307 	const struct acl_entry *entry;
1308 
1309 	/*
1310 	 * The spec doesn't seem to say anything about ACL validity.
1311 	 * It seems there is not much to do here.  There is even no need
1312 	 * to count "owner@" or "everyone@" (ACL_USER_OBJ and ACL_EVERYONE)
1313 	 * entries, as there can be several of them and that's perfectly
1314 	 * valid.  There can be none of them too.  Really.
1315 	 */
1316 
1317 	if (aclp->acl_cnt > ACL_MAX_ENTRIES || aclp->acl_cnt <= 0)
1318 		return (EINVAL);
1319 
1320 	for (i = 0; i < aclp->acl_cnt; i++) {
1321 		entry = &(aclp->acl_entry[i]);
1322 
1323 		switch (entry->ae_tag) {
1324 		case ACL_USER_OBJ:
1325 		case ACL_GROUP_OBJ:
1326 		case ACL_EVERYONE:
1327 			if (entry->ae_id != ACL_UNDEFINED_ID)
1328 				return (EINVAL);
1329 			break;
1330 
1331 		case ACL_USER:
1332 		case ACL_GROUP:
1333 			if (entry->ae_id == ACL_UNDEFINED_ID)
1334 				return (EINVAL);
1335 			break;
1336 
1337 		default:
1338 			return (EINVAL);
1339 		}
1340 
1341 		if ((entry->ae_perm | ACL_NFS4_PERM_BITS) != ACL_NFS4_PERM_BITS)
1342 			return (EINVAL);
1343 
1344 		/*
1345 		 * Disallow ACL_ENTRY_TYPE_AUDIT and ACL_ENTRY_TYPE_ALARM for now.
1346 		 */
1347 		if (entry->ae_entry_type != ACL_ENTRY_TYPE_ALLOW &&
1348 		    entry->ae_entry_type != ACL_ENTRY_TYPE_DENY)
1349 			return (EINVAL);
1350 
1351 		if ((entry->ae_flags | ACL_FLAGS_BITS) != ACL_FLAGS_BITS)
1352 			return (EINVAL);
1353 
1354 		/* Disallow unimplemented flags. */
1355 		if (entry->ae_flags & (ACL_ENTRY_SUCCESSFUL_ACCESS |
1356 		    ACL_ENTRY_FAILED_ACCESS))
1357 			return (EINVAL);
1358 
1359 		/* Disallow flags not allowed for ordinary files. */
1360 		if (!is_directory) {
1361 			if (entry->ae_flags & (ACL_ENTRY_FILE_INHERIT |
1362 			    ACL_ENTRY_DIRECTORY_INHERIT |
1363 			    ACL_ENTRY_NO_PROPAGATE_INHERIT | ACL_ENTRY_INHERIT_ONLY))
1364 				return (EINVAL);
1365 		}
1366 	}
1367 
1368 	return (0);
1369 }
1370