xref: /openbmc/linux/fs/nfsd/nfs4acl.c (revision d5cb9783536a41df9f9cba5b0a1d78047ed787f7)
1 /*
2  *  fs/nfs4acl/acl.c
3  *
4  *  Common NFSv4 ACL handling code.
5  *
6  *  Copyright (c) 2002, 2003 The Regents of the University of Michigan.
7  *  All rights reserved.
8  *
9  *  Marius Aamodt Eriksen <marius@umich.edu>
10  *  Jeff Sedlak <jsedlak@umich.edu>
11  *  J. Bruce Fields <bfields@umich.edu>
12  *
13  *  Redistribution and use in source and binary forms, with or without
14  *  modification, are permitted provided that the following conditions
15  *  are met:
16  *
17  *  1. Redistributions of source code must retain the above copyright
18  *     notice, this list of conditions and the following disclaimer.
19  *  2. Redistributions in binary form must reproduce the above copyright
20  *     notice, this list of conditions and the following disclaimer in the
21  *     documentation and/or other materials provided with the distribution.
22  *  3. Neither the name of the University nor the names of its
23  *     contributors may be used to endorse or promote products derived
24  *     from this software without specific prior written permission.
25  *
26  *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
27  *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
28  *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
29  *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30  *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31  *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32  *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
33  *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
34  *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
35  *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
36  *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
37  */
38 
39 #include <linux/string.h>
40 #include <linux/slab.h>
41 #include <linux/list.h>
42 #include <linux/types.h>
43 #include <linux/fs.h>
44 #include <linux/module.h>
45 #include <linux/nfs_fs.h>
46 #include <linux/posix_acl.h>
47 #include <linux/nfs4.h>
48 #include <linux/nfs4_acl.h>
49 
50 
51 /* mode bit translations: */
52 #define NFS4_READ_MODE (NFS4_ACE_READ_DATA)
53 #define NFS4_WRITE_MODE (NFS4_ACE_WRITE_DATA | NFS4_ACE_APPEND_DATA)
54 #define NFS4_EXECUTE_MODE NFS4_ACE_EXECUTE
55 #define NFS4_ANYONE_MODE (NFS4_ACE_READ_ATTRIBUTES | NFS4_ACE_READ_ACL | NFS4_ACE_SYNCHRONIZE)
56 #define NFS4_OWNER_MODE (NFS4_ACE_WRITE_ATTRIBUTES | NFS4_ACE_WRITE_ACL)
57 
58 /* We don't support these bits; insist they be neither allowed nor denied */
59 #define NFS4_MASK_UNSUPP (NFS4_ACE_DELETE | NFS4_ACE_WRITE_OWNER \
60 		| NFS4_ACE_READ_NAMED_ATTRS | NFS4_ACE_WRITE_NAMED_ATTRS)
61 
62 /* flags used to simulate posix default ACLs */
63 #define NFS4_INHERITANCE_FLAGS (NFS4_ACE_FILE_INHERIT_ACE \
64 		| NFS4_ACE_DIRECTORY_INHERIT_ACE | NFS4_ACE_INHERIT_ONLY_ACE)
65 
66 #define MASK_EQUAL(mask1, mask2) \
67 	( ((mask1) & NFS4_ACE_MASK_ALL) == ((mask2) & NFS4_ACE_MASK_ALL) )
68 
69 static u32
70 mask_from_posix(unsigned short perm, unsigned int flags)
71 {
72 	int mask = NFS4_ANYONE_MODE;
73 
74 	if (flags & NFS4_ACL_OWNER)
75 		mask |= NFS4_OWNER_MODE;
76 	if (perm & ACL_READ)
77 		mask |= NFS4_READ_MODE;
78 	if (perm & ACL_WRITE)
79 		mask |= NFS4_WRITE_MODE;
80 	if ((perm & ACL_WRITE) && (flags & NFS4_ACL_DIR))
81 		mask |= NFS4_ACE_DELETE_CHILD;
82 	if (perm & ACL_EXECUTE)
83 		mask |= NFS4_EXECUTE_MODE;
84 	return mask;
85 }
86 
87 static u32
88 deny_mask(u32 allow_mask, unsigned int flags)
89 {
90 	u32 ret = ~allow_mask & ~NFS4_MASK_UNSUPP;
91 	if (!(flags & NFS4_ACL_DIR))
92 		ret &= ~NFS4_ACE_DELETE_CHILD;
93 	return ret;
94 }
95 
96 /* XXX: modify functions to return NFS errors; they're only ever
97  * used by nfs code, after all.... */
98 
99 static int
100 mode_from_nfs4(u32 perm, unsigned short *mode, unsigned int flags)
101 {
102 	u32 ignore = 0;
103 
104 	if (!(flags & NFS4_ACL_DIR))
105 		ignore |= NFS4_ACE_DELETE_CHILD; /* ignore it */
106 	perm |= ignore;
107 	*mode = 0;
108 	if ((perm & NFS4_READ_MODE) == NFS4_READ_MODE)
109 		*mode |= ACL_READ;
110 	if ((perm & NFS4_WRITE_MODE) == NFS4_WRITE_MODE)
111 		*mode |= ACL_WRITE;
112 	if ((perm & NFS4_EXECUTE_MODE) == NFS4_EXECUTE_MODE)
113 		*mode |= ACL_EXECUTE;
114 	if (!MASK_EQUAL(perm, ignore|mask_from_posix(*mode, flags)))
115 		return -EINVAL;
116 	return 0;
117 }
118 
119 struct ace_container {
120 	struct nfs4_ace  *ace;
121 	struct list_head  ace_l;
122 };
123 
124 static short ace2type(struct nfs4_ace *);
125 static int _posix_to_nfsv4_one(struct posix_acl *, struct nfs4_acl *, unsigned int);
126 static struct posix_acl *_nfsv4_to_posix_one(struct nfs4_acl *, unsigned int);
127 int nfs4_acl_add_ace(struct nfs4_acl *, u32, u32, u32, int, uid_t);
128 static int nfs4_acl_split(struct nfs4_acl *, struct nfs4_acl *);
129 
130 struct nfs4_acl *
131 nfs4_acl_posix_to_nfsv4(struct posix_acl *pacl, struct posix_acl *dpacl,
132 			unsigned int flags)
133 {
134 	struct nfs4_acl *acl;
135 	int error = -EINVAL;
136 
137 	if ((pacl != NULL &&
138 		(posix_acl_valid(pacl) < 0 || pacl->a_count == 0)) ||
139 	    (dpacl != NULL &&
140 		(posix_acl_valid(dpacl) < 0 || dpacl->a_count == 0)))
141 		goto out_err;
142 
143 	acl = nfs4_acl_new();
144 	if (acl == NULL) {
145 		error = -ENOMEM;
146 		goto out_err;
147 	}
148 
149 	if (pacl != NULL) {
150 		error = _posix_to_nfsv4_one(pacl, acl,
151 						flags & ~NFS4_ACL_TYPE_DEFAULT);
152 		if (error < 0)
153 			goto out_acl;
154 	}
155 
156 	if (dpacl != NULL) {
157 		error = _posix_to_nfsv4_one(dpacl, acl,
158 						flags | NFS4_ACL_TYPE_DEFAULT);
159 		if (error < 0)
160 			goto out_acl;
161 	}
162 
163 	return acl;
164 
165 out_acl:
166 	nfs4_acl_free(acl);
167 out_err:
168 	acl = ERR_PTR(error);
169 
170 	return acl;
171 }
172 
173 static int
174 nfs4_acl_add_pair(struct nfs4_acl *acl, int eflag, u32 mask, int whotype,
175 		uid_t owner, unsigned int flags)
176 {
177 	int error;
178 
179 	error = nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE,
180 				 eflag, mask, whotype, owner);
181 	if (error < 0)
182 		return error;
183 	error = nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_DENIED_ACE_TYPE,
184 				eflag, deny_mask(mask, flags), whotype, owner);
185 	return error;
186 }
187 
188 /* We assume the acl has been verified with posix_acl_valid. */
189 static int
190 _posix_to_nfsv4_one(struct posix_acl *pacl, struct nfs4_acl *acl,
191 						unsigned int flags)
192 {
193 	struct posix_acl_entry *pa, *pe, *group_owner_entry;
194 	int error = -EINVAL;
195 	u32 mask, mask_mask;
196 	int eflag = ((flags & NFS4_ACL_TYPE_DEFAULT) ?
197 					NFS4_INHERITANCE_FLAGS : 0);
198 
199 	BUG_ON(pacl->a_count < 3);
200 	pe = pacl->a_entries + pacl->a_count;
201 	pa = pe - 2; /* if mask entry exists, it's second from the last. */
202 	if (pa->e_tag == ACL_MASK)
203 		mask_mask = deny_mask(mask_from_posix(pa->e_perm, flags), flags);
204 	else
205 		mask_mask = 0;
206 
207 	pa = pacl->a_entries;
208 	BUG_ON(pa->e_tag != ACL_USER_OBJ);
209 	mask = mask_from_posix(pa->e_perm, flags | NFS4_ACL_OWNER);
210 	error = nfs4_acl_add_pair(acl, eflag, mask, NFS4_ACL_WHO_OWNER, 0, flags);
211 	if (error < 0)
212 		goto out;
213 	pa++;
214 
215 	while (pa->e_tag == ACL_USER) {
216 		mask = mask_from_posix(pa->e_perm, flags);
217 		error = nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_DENIED_ACE_TYPE,
218 				eflag,  mask_mask, NFS4_ACL_WHO_NAMED, pa->e_id);
219 		if (error < 0)
220 			goto out;
221 
222 
223 		error = nfs4_acl_add_pair(acl, eflag, mask,
224 				NFS4_ACL_WHO_NAMED, pa->e_id, flags);
225 		if (error < 0)
226 			goto out;
227 		pa++;
228 	}
229 
230 	/* In the case of groups, we apply allow ACEs first, then deny ACEs,
231 	 * since a user can be in more than one group.  */
232 
233 	/* allow ACEs */
234 
235 	if (pacl->a_count > 3) {
236 		BUG_ON(pa->e_tag != ACL_GROUP_OBJ);
237 		error = nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_DENIED_ACE_TYPE,
238 				NFS4_ACE_IDENTIFIER_GROUP | eflag, mask_mask,
239 				NFS4_ACL_WHO_GROUP, 0);
240 		if (error < 0)
241 			goto out;
242 	}
243 	group_owner_entry = pa;
244 	mask = mask_from_posix(pa->e_perm, flags);
245 	error = nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE,
246 			NFS4_ACE_IDENTIFIER_GROUP | eflag, mask,
247 			NFS4_ACL_WHO_GROUP, 0);
248 	if (error < 0)
249 		goto out;
250 	pa++;
251 
252 	while (pa->e_tag == ACL_GROUP) {
253 		mask = mask_from_posix(pa->e_perm, flags);
254 		error = nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_DENIED_ACE_TYPE,
255 				NFS4_ACE_IDENTIFIER_GROUP | eflag, mask_mask,
256 				NFS4_ACL_WHO_NAMED, pa->e_id);
257 		if (error < 0)
258 			goto out;
259 
260 		error = nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE,
261 		    		NFS4_ACE_IDENTIFIER_GROUP | eflag, mask,
262 		    		NFS4_ACL_WHO_NAMED, pa->e_id);
263 		if (error < 0)
264 			goto out;
265 		pa++;
266 	}
267 
268 	/* deny ACEs */
269 
270 	pa = group_owner_entry;
271 	mask = mask_from_posix(pa->e_perm, flags);
272 	error = nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_DENIED_ACE_TYPE,
273 			NFS4_ACE_IDENTIFIER_GROUP | eflag,
274 			deny_mask(mask, flags), NFS4_ACL_WHO_GROUP, 0);
275 	if (error < 0)
276 		goto out;
277 	pa++;
278 	while (pa->e_tag == ACL_GROUP) {
279 		mask = mask_from_posix(pa->e_perm, flags);
280 		error = nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_DENIED_ACE_TYPE,
281 		    		NFS4_ACE_IDENTIFIER_GROUP | eflag,
282 		    		deny_mask(mask, flags), NFS4_ACL_WHO_NAMED, pa->e_id);
283 		if (error < 0)
284 			goto out;
285 		pa++;
286 	}
287 
288 	if (pa->e_tag == ACL_MASK)
289 		pa++;
290 	BUG_ON(pa->e_tag != ACL_OTHER);
291 	mask = mask_from_posix(pa->e_perm, flags);
292 	error = nfs4_acl_add_pair(acl, eflag, mask, NFS4_ACL_WHO_EVERYONE, 0, flags);
293 
294 out:
295 	return error;
296 }
297 
298 static void
299 sort_pacl_range(struct posix_acl *pacl, int start, int end) {
300 	int sorted = 0, i;
301 	struct posix_acl_entry tmp;
302 
303 	/* We just do a bubble sort; easy to do in place, and we're not
304 	 * expecting acl's to be long enough to justify anything more. */
305 	while (!sorted) {
306 		sorted = 1;
307 		for (i = start; i < end; i++) {
308 			if (pacl->a_entries[i].e_id
309 					> pacl->a_entries[i+1].e_id) {
310 				sorted = 0;
311 				tmp = pacl->a_entries[i];
312 				pacl->a_entries[i] = pacl->a_entries[i+1];
313 				pacl->a_entries[i+1] = tmp;
314 			}
315 		}
316 	}
317 }
318 
319 static void
320 sort_pacl(struct posix_acl *pacl)
321 {
322 	/* posix_acl_valid requires that users and groups be in order
323 	 * by uid/gid. */
324 	int i, j;
325 
326 	if (pacl->a_count <= 4)
327 		return; /* no users or groups */
328 	i = 1;
329 	while (pacl->a_entries[i].e_tag == ACL_USER)
330 		i++;
331 	sort_pacl_range(pacl, 1, i-1);
332 
333 	BUG_ON(pacl->a_entries[i].e_tag != ACL_GROUP_OBJ);
334 	j = i++;
335 	while (pacl->a_entries[j].e_tag == ACL_GROUP)
336 		j++;
337 	sort_pacl_range(pacl, i, j-1);
338 	return;
339 }
340 
341 static int
342 write_pace(struct nfs4_ace *ace, struct posix_acl *pacl,
343 		struct posix_acl_entry **pace, short tag, unsigned int flags)
344 {
345 	struct posix_acl_entry *this = *pace;
346 
347 	if (*pace == pacl->a_entries + pacl->a_count)
348 		return -EINVAL; /* fell off the end */
349 	(*pace)++;
350 	this->e_tag = tag;
351 	if (tag == ACL_USER_OBJ)
352 		flags |= NFS4_ACL_OWNER;
353 	if (mode_from_nfs4(ace->access_mask, &this->e_perm, flags))
354 		return -EINVAL;
355 	this->e_id = (tag == ACL_USER || tag == ACL_GROUP ?
356 			ace->who : ACL_UNDEFINED_ID);
357 	return 0;
358 }
359 
360 static struct nfs4_ace *
361 get_next_v4_ace(struct list_head **p, struct list_head *head)
362 {
363 	struct nfs4_ace *ace;
364 
365 	*p = (*p)->next;
366 	if (*p == head)
367 		return NULL;
368 	ace = list_entry(*p, struct nfs4_ace, l_ace);
369 
370 	return ace;
371 }
372 
373 int
374 nfs4_acl_nfsv4_to_posix(struct nfs4_acl *acl, struct posix_acl **pacl,
375 		struct posix_acl **dpacl, unsigned int flags)
376 {
377 	struct nfs4_acl *dacl;
378 	int error = -ENOMEM;
379 
380 	*pacl = NULL;
381 	*dpacl = NULL;
382 
383 	dacl = nfs4_acl_new();
384 	if (dacl == NULL)
385 		goto out;
386 
387 	error = nfs4_acl_split(acl, dacl);
388 	if (error < 0)
389 		goto out_acl;
390 
391 	if (pacl != NULL) {
392 		if (acl->naces == 0) {
393 			error = -ENODATA;
394 			goto try_dpacl;
395 		}
396 
397 		*pacl = _nfsv4_to_posix_one(acl, flags);
398 		if (IS_ERR(*pacl)) {
399 			error = PTR_ERR(*pacl);
400 			*pacl = NULL;
401 			goto out_acl;
402 		}
403 	}
404 
405 try_dpacl:
406 	if (dpacl != NULL) {
407 		if (dacl->naces == 0) {
408 			if (pacl == NULL || *pacl == NULL)
409 				error = -ENODATA;
410 			goto out_acl;
411 		}
412 
413 		error = 0;
414 		*dpacl = _nfsv4_to_posix_one(dacl, flags);
415 		if (IS_ERR(*dpacl)) {
416 			error = PTR_ERR(*dpacl);
417 			*dpacl = NULL;
418 			goto out_acl;
419 		}
420 	}
421 
422 out_acl:
423 	if (error && pacl) {
424 		posix_acl_release(*pacl);
425 		*pacl = NULL;
426 	}
427 	nfs4_acl_free(dacl);
428 out:
429 	return error;
430 }
431 
432 static int
433 same_who(struct nfs4_ace *a, struct nfs4_ace *b)
434 {
435 	return a->whotype == b->whotype &&
436 		(a->whotype != NFS4_ACL_WHO_NAMED || a->who == b->who);
437 }
438 
439 static int
440 complementary_ace_pair(struct nfs4_ace *allow, struct nfs4_ace *deny,
441 		unsigned int flags)
442 {
443 	int ignore = 0;
444 	if (!(flags & NFS4_ACL_DIR))
445 		ignore |= NFS4_ACE_DELETE_CHILD;
446 	return MASK_EQUAL(ignore|deny_mask(allow->access_mask, flags),
447 			  ignore|deny->access_mask) &&
448 		allow->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE &&
449 		deny->type == NFS4_ACE_ACCESS_DENIED_ACE_TYPE &&
450 		allow->flag == deny->flag &&
451 		same_who(allow, deny);
452 }
453 
454 static inline int
455 user_obj_from_v4(struct nfs4_acl *n4acl, struct list_head **p,
456 		struct posix_acl *pacl, struct posix_acl_entry **pace,
457 		unsigned int flags)
458 {
459 	int error = -EINVAL;
460 	struct nfs4_ace *ace, *ace2;
461 
462 	ace = get_next_v4_ace(p, &n4acl->ace_head);
463 	if (ace == NULL)
464 		goto out;
465 	if (ace2type(ace) != ACL_USER_OBJ)
466 		goto out;
467 	error = write_pace(ace, pacl, pace, ACL_USER_OBJ, flags);
468 	if (error < 0)
469 		goto out;
470 	error = -EINVAL;
471 	ace2 = get_next_v4_ace(p, &n4acl->ace_head);
472 	if (ace2 == NULL)
473 		goto out;
474 	if (!complementary_ace_pair(ace, ace2, flags))
475 		goto out;
476 	error = 0;
477 out:
478 	return error;
479 }
480 
481 static inline int
482 users_from_v4(struct nfs4_acl *n4acl, struct list_head **p,
483 		struct nfs4_ace **mask_ace,
484 		struct posix_acl *pacl, struct posix_acl_entry **pace,
485 		unsigned int flags)
486 {
487 	int error = -EINVAL;
488 	struct nfs4_ace *ace, *ace2;
489 
490 	ace = get_next_v4_ace(p, &n4acl->ace_head);
491 	if (ace == NULL)
492 		goto out;
493 	while (ace2type(ace) == ACL_USER) {
494 		if (ace->type != NFS4_ACE_ACCESS_DENIED_ACE_TYPE)
495 			goto out;
496 		if (*mask_ace &&
497 			!MASK_EQUAL(ace->access_mask, (*mask_ace)->access_mask))
498 			goto out;
499 		*mask_ace = ace;
500 		ace = get_next_v4_ace(p, &n4acl->ace_head);
501 		if (ace == NULL)
502 			goto out;
503 		if (ace->type != NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE)
504 			goto out;
505 		error = write_pace(ace, pacl, pace, ACL_USER, flags);
506 		if (error < 0)
507 			goto out;
508 		error = -EINVAL;
509 		ace2 = get_next_v4_ace(p, &n4acl->ace_head);
510 		if (ace2 == NULL)
511 			goto out;
512 		if (!complementary_ace_pair(ace, ace2, flags))
513 			goto out;
514 		if ((*mask_ace)->flag != ace2->flag ||
515 				!same_who(*mask_ace, ace2))
516 			goto out;
517 		ace = get_next_v4_ace(p, &n4acl->ace_head);
518 		if (ace == NULL)
519 			goto out;
520 	}
521 	error = 0;
522 out:
523 	return error;
524 }
525 
526 static inline int
527 group_obj_and_groups_from_v4(struct nfs4_acl *n4acl, struct list_head **p,
528 		struct nfs4_ace **mask_ace,
529 		struct posix_acl *pacl, struct posix_acl_entry **pace,
530 		unsigned int flags)
531 {
532 	int error = -EINVAL;
533 	struct nfs4_ace *ace, *ace2;
534 	struct ace_container *ac;
535 	struct list_head group_l;
536 
537 	INIT_LIST_HEAD(&group_l);
538 	ace = list_entry(*p, struct nfs4_ace, l_ace);
539 
540 	/* group owner (mask and allow aces) */
541 
542 	if (pacl->a_count != 3) {
543 		/* then the group owner should be preceded by mask */
544 		if (ace->type != NFS4_ACE_ACCESS_DENIED_ACE_TYPE)
545 			goto out;
546 		if (*mask_ace &&
547 			!MASK_EQUAL(ace->access_mask, (*mask_ace)->access_mask))
548 			goto out;
549 		*mask_ace = ace;
550 		ace = get_next_v4_ace(p, &n4acl->ace_head);
551 		if (ace == NULL)
552 			goto out;
553 
554 		if ((*mask_ace)->flag != ace->flag || !same_who(*mask_ace, ace))
555 			goto out;
556 	}
557 
558 	if (ace2type(ace) != ACL_GROUP_OBJ)
559 		goto out;
560 
561 	ac = kmalloc(sizeof(*ac), GFP_KERNEL);
562 	error = -ENOMEM;
563 	if (ac == NULL)
564 		goto out;
565 	ac->ace = ace;
566 	list_add_tail(&ac->ace_l, &group_l);
567 
568 	error = -EINVAL;
569 	if (ace->type != NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE)
570 		goto out;
571 
572 	error = write_pace(ace, pacl, pace, ACL_GROUP_OBJ, flags);
573 	if (error < 0)
574 		goto out;
575 
576 	error = -EINVAL;
577 	ace = get_next_v4_ace(p, &n4acl->ace_head);
578 	if (ace == NULL)
579 		goto out;
580 
581 	/* groups (mask and allow aces) */
582 
583 	while (ace2type(ace) == ACL_GROUP) {
584 		if (*mask_ace == NULL)
585 			goto out;
586 
587 		if (ace->type != NFS4_ACE_ACCESS_DENIED_ACE_TYPE ||
588 			!MASK_EQUAL(ace->access_mask, (*mask_ace)->access_mask))
589 			goto out;
590 		*mask_ace = ace;
591 
592 		ace = get_next_v4_ace(p, &n4acl->ace_head);
593 		if (ace == NULL)
594 			goto out;
595 		ac = kmalloc(sizeof(*ac), GFP_KERNEL);
596 		error = -ENOMEM;
597 		if (ac == NULL)
598 			goto out;
599 		error = -EINVAL;
600 		if (ace->type != NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE ||
601 				!same_who(ace, *mask_ace))
602 			goto out;
603 
604 		ac->ace = ace;
605 		list_add_tail(&ac->ace_l, &group_l);
606 
607 		error = write_pace(ace, pacl, pace, ACL_GROUP, flags);
608 		if (error < 0)
609 			goto out;
610 		error = -EINVAL;
611 		ace = get_next_v4_ace(p, &n4acl->ace_head);
612 		if (ace == NULL)
613 			goto out;
614 	}
615 
616 	/* group owner (deny ace) */
617 
618 	if (ace2type(ace) != ACL_GROUP_OBJ)
619 		goto out;
620 	ac = list_entry(group_l.next, struct ace_container, ace_l);
621 	ace2 = ac->ace;
622 	if (!complementary_ace_pair(ace2, ace, flags))
623 		goto out;
624 	list_del(group_l.next);
625 	kfree(ac);
626 
627 	/* groups (deny aces) */
628 
629 	while (!list_empty(&group_l)) {
630 		ace = get_next_v4_ace(p, &n4acl->ace_head);
631 		if (ace == NULL)
632 			goto out;
633 		if (ace2type(ace) != ACL_GROUP)
634 			goto out;
635 		ac = list_entry(group_l.next, struct ace_container, ace_l);
636 		ace2 = ac->ace;
637 		if (!complementary_ace_pair(ace2, ace, flags))
638 			goto out;
639 		list_del(group_l.next);
640 		kfree(ac);
641 	}
642 
643 	ace = get_next_v4_ace(p, &n4acl->ace_head);
644 	if (ace == NULL)
645 		goto out;
646 	if (ace2type(ace) != ACL_OTHER)
647 		goto out;
648 	error = 0;
649 out:
650 	while (!list_empty(&group_l)) {
651 		ac = list_entry(group_l.next, struct ace_container, ace_l);
652 		list_del(group_l.next);
653 		kfree(ac);
654 	}
655 	return error;
656 }
657 
658 static inline int
659 mask_from_v4(struct nfs4_acl *n4acl, struct list_head **p,
660 		struct nfs4_ace **mask_ace,
661 		struct posix_acl *pacl, struct posix_acl_entry **pace,
662 		unsigned int flags)
663 {
664 	int error = -EINVAL;
665 	struct nfs4_ace *ace;
666 
667 	ace = list_entry(*p, struct nfs4_ace, l_ace);
668 	if (pacl->a_count != 3) {
669 		if (*mask_ace == NULL)
670 			goto out;
671 		(*mask_ace)->access_mask = deny_mask((*mask_ace)->access_mask, flags);
672 		write_pace(*mask_ace, pacl, pace, ACL_MASK, flags);
673 	}
674 	error = 0;
675 out:
676 	return error;
677 }
678 
679 static inline int
680 other_from_v4(struct nfs4_acl *n4acl, struct list_head **p,
681 		struct posix_acl *pacl, struct posix_acl_entry **pace,
682 		unsigned int flags)
683 {
684 	int error = -EINVAL;
685 	struct nfs4_ace *ace, *ace2;
686 
687 	ace = list_entry(*p, struct nfs4_ace, l_ace);
688 	if (ace->type != NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE)
689 		goto out;
690 	error = write_pace(ace, pacl, pace, ACL_OTHER, flags);
691 	if (error < 0)
692 		goto out;
693 	error = -EINVAL;
694 	ace2 = get_next_v4_ace(p, &n4acl->ace_head);
695 	if (ace2 == NULL)
696 		goto out;
697 	if (!complementary_ace_pair(ace, ace2, flags))
698 		goto out;
699 	error = 0;
700 out:
701 	return error;
702 }
703 
704 static int
705 calculate_posix_ace_count(struct nfs4_acl *n4acl)
706 {
707 	if (n4acl->naces == 6) /* owner, owner group, and other only */
708 		return 3;
709 	else { /* Otherwise there must be a mask entry. */
710 		/* Also, the remaining entries are for named users and
711 		 * groups, and come in threes (mask, allow, deny): */
712 		if (n4acl->naces < 7)
713 			return -1;
714 		if ((n4acl->naces - 7) % 3)
715 			return -1;
716 		return 4 + (n4acl->naces - 7)/3;
717 	}
718 }
719 
720 
721 static struct posix_acl *
722 _nfsv4_to_posix_one(struct nfs4_acl *n4acl, unsigned int flags)
723 {
724 	struct posix_acl *pacl;
725 	int error = -EINVAL, nace = 0;
726 	struct list_head *p;
727 	struct nfs4_ace *mask_ace = NULL;
728 	struct posix_acl_entry *pace;
729 
730 	nace = calculate_posix_ace_count(n4acl);
731 	if (nace < 0)
732 		goto out_err;
733 
734 	pacl = posix_acl_alloc(nace, GFP_KERNEL);
735 	error = -ENOMEM;
736 	if (pacl == NULL)
737 		goto out_err;
738 
739 	pace = &pacl->a_entries[0];
740 	p = &n4acl->ace_head;
741 
742 	error = user_obj_from_v4(n4acl, &p, pacl, &pace, flags);
743 	if (error)
744 		goto out_acl;
745 
746 	error = users_from_v4(n4acl, &p, &mask_ace, pacl, &pace, flags);
747 	if (error)
748 		goto out_acl;
749 
750 	error = group_obj_and_groups_from_v4(n4acl, &p, &mask_ace, pacl, &pace,
751 						flags);
752 	if (error)
753 		goto out_acl;
754 
755 	error = mask_from_v4(n4acl, &p, &mask_ace, pacl, &pace, flags);
756 	if (error)
757 		goto out_acl;
758 	error = other_from_v4(n4acl, &p, pacl, &pace, flags);
759 	if (error)
760 		goto out_acl;
761 
762 	error = -EINVAL;
763 	if (p->next != &n4acl->ace_head)
764 		goto out_acl;
765 	if (pace != pacl->a_entries + pacl->a_count)
766 		goto out_acl;
767 
768 	sort_pacl(pacl);
769 
770 	return pacl;
771 out_acl:
772 	posix_acl_release(pacl);
773 out_err:
774 	pacl = ERR_PTR(error);
775 	return pacl;
776 }
777 
778 static int
779 nfs4_acl_split(struct nfs4_acl *acl, struct nfs4_acl *dacl)
780 {
781 	struct list_head *h, *n;
782 	struct nfs4_ace *ace;
783 	int error = 0;
784 
785 	list_for_each_safe(h, n, &acl->ace_head) {
786 		ace = list_entry(h, struct nfs4_ace, l_ace);
787 
788 		if ((ace->flag & NFS4_INHERITANCE_FLAGS)
789 				!= NFS4_INHERITANCE_FLAGS)
790 			continue;
791 
792 		error = nfs4_acl_add_ace(dacl, ace->type, ace->flag,
793 				ace->access_mask, ace->whotype, ace->who) == -1;
794 		if (error < 0)
795 			goto out;
796 
797 		list_del(h);
798 		kfree(ace);
799 		acl->naces--;
800 	}
801 
802 out:
803 	return error;
804 }
805 
806 static short
807 ace2type(struct nfs4_ace *ace)
808 {
809 	switch (ace->whotype) {
810 		case NFS4_ACL_WHO_NAMED:
811 			return (ace->flag & NFS4_ACE_IDENTIFIER_GROUP ?
812 					ACL_GROUP : ACL_USER);
813 		case NFS4_ACL_WHO_OWNER:
814 			return ACL_USER_OBJ;
815 		case NFS4_ACL_WHO_GROUP:
816 			return ACL_GROUP_OBJ;
817 		case NFS4_ACL_WHO_EVERYONE:
818 			return ACL_OTHER;
819 	}
820 	BUG();
821 	return -1;
822 }
823 
824 EXPORT_SYMBOL(nfs4_acl_posix_to_nfsv4);
825 EXPORT_SYMBOL(nfs4_acl_nfsv4_to_posix);
826 
827 struct nfs4_acl *
828 nfs4_acl_new(void)
829 {
830 	struct nfs4_acl *acl;
831 
832 	if ((acl = kmalloc(sizeof(*acl), GFP_KERNEL)) == NULL)
833 		return NULL;
834 
835 	acl->naces = 0;
836 	INIT_LIST_HEAD(&acl->ace_head);
837 
838 	return acl;
839 }
840 
841 void
842 nfs4_acl_free(struct nfs4_acl *acl)
843 {
844 	struct list_head *h;
845 	struct nfs4_ace *ace;
846 
847 	if (!acl)
848 		return;
849 
850 	while (!list_empty(&acl->ace_head)) {
851 		h = acl->ace_head.next;
852 		list_del(h);
853 		ace = list_entry(h, struct nfs4_ace, l_ace);
854 		kfree(ace);
855 	}
856 
857 	kfree(acl);
858 
859 	return;
860 }
861 
862 int
863 nfs4_acl_add_ace(struct nfs4_acl *acl, u32 type, u32 flag, u32 access_mask,
864 		int whotype, uid_t who)
865 {
866 	struct nfs4_ace *ace;
867 
868 	if ((ace = kmalloc(sizeof(*ace), GFP_KERNEL)) == NULL)
869 		return -1;
870 
871 	ace->type = type;
872 	ace->flag = flag;
873 	ace->access_mask = access_mask;
874 	ace->whotype = whotype;
875 	ace->who = who;
876 
877 	list_add_tail(&ace->l_ace, &acl->ace_head);
878 	acl->naces++;
879 
880 	return 0;
881 }
882 
883 static struct {
884 	char *string;
885 	int   stringlen;
886 	int type;
887 } s2t_map[] = {
888 	{
889 		.string    = "OWNER@",
890 		.stringlen = sizeof("OWNER@") - 1,
891 		.type      = NFS4_ACL_WHO_OWNER,
892 	},
893 	{
894 		.string    = "GROUP@",
895 		.stringlen = sizeof("GROUP@") - 1,
896 		.type      = NFS4_ACL_WHO_GROUP,
897 	},
898 	{
899 		.string    = "EVERYONE@",
900 		.stringlen = sizeof("EVERYONE@") - 1,
901 		.type      = NFS4_ACL_WHO_EVERYONE,
902 	},
903 };
904 
905 int
906 nfs4_acl_get_whotype(char *p, u32 len)
907 {
908 	int i;
909 
910 	for (i=0; i < sizeof(s2t_map) / sizeof(*s2t_map); i++) {
911 		if (s2t_map[i].stringlen == len &&
912 				0 == memcmp(s2t_map[i].string, p, len))
913 			return s2t_map[i].type;
914 	}
915 	return NFS4_ACL_WHO_NAMED;
916 }
917 
918 int
919 nfs4_acl_write_who(int who, char *p)
920 {
921 	int i;
922 
923 	for (i=0; i < sizeof(s2t_map) / sizeof(*s2t_map); i++) {
924 		if (s2t_map[i].type == who) {
925 			memcpy(p, s2t_map[i].string, s2t_map[i].stringlen);
926 			return s2t_map[i].stringlen;
927 		}
928 	}
929 	BUG();
930 	return -1;
931 }
932 
933 static inline int
934 match_who(struct nfs4_ace *ace, uid_t owner, gid_t group, uid_t who)
935 {
936 	switch (ace->whotype) {
937 		case NFS4_ACL_WHO_NAMED:
938 			return who == ace->who;
939 		case NFS4_ACL_WHO_OWNER:
940 			return who == owner;
941 		case NFS4_ACL_WHO_GROUP:
942 			return who == group;
943 		case NFS4_ACL_WHO_EVERYONE:
944 			return 1;
945 		default:
946 			return 0;
947 	}
948 }
949 
950 EXPORT_SYMBOL(nfs4_acl_new);
951 EXPORT_SYMBOL(nfs4_acl_free);
952 EXPORT_SYMBOL(nfs4_acl_add_ace);
953 EXPORT_SYMBOL(nfs4_acl_get_whotype);
954 EXPORT_SYMBOL(nfs4_acl_write_who);
955