1/*
  2 *  Common NFSv4 ACL handling code.
  3 *
  4 *  Copyright (c) 2002, 2003 The Regents of the University of Michigan.
  5 *  All rights reserved.
  6 *
  7 *  Marius Aamodt Eriksen <marius@umich.edu>
  8 *  Jeff Sedlak <jsedlak@umich.edu>
  9 *  J. Bruce Fields <bfields@umich.edu>
 10 *
 11 *  Redistribution and use in source and binary forms, with or without
 12 *  modification, are permitted provided that the following conditions
 13 *  are met:
 14 *
 15 *  1. Redistributions of source code must retain the above copyright
 16 *     notice, this list of conditions and the following disclaimer.
 17 *  2. Redistributions in binary form must reproduce the above copyright
 18 *     notice, this list of conditions and the following disclaimer in the
 19 *     documentation and/or other materials provided with the distribution.
 20 *  3. Neither the name of the University nor the names of its
 21 *     contributors may be used to endorse or promote products derived
 22 *     from this software without specific prior written permission.
 23 *
 24 *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
 25 *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 26 *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 27 *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 28 *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 29 *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 30 *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 31 *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 32 *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 33 *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 34 *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 35 */
 36
 37#include <linux/fs.h>
 38#include <linux/slab.h>
 39#include <linux/posix_acl.h>
 40
 41#include "nfsfh.h"
 42#include "nfsd.h"
 43#include "acl.h"
 44#include "vfs.h"
 45
 46#define NFS4_ACL_TYPE_DEFAULT	0x01
 47#define NFS4_ACL_DIR		0x02
 48#define NFS4_ACL_OWNER		0x04
 49
 50/* mode bit translations: */
 51#define NFS4_READ_MODE (NFS4_ACE_READ_DATA)
 52#define NFS4_WRITE_MODE (NFS4_ACE_WRITE_DATA | NFS4_ACE_APPEND_DATA)
 53#define NFS4_EXECUTE_MODE NFS4_ACE_EXECUTE
 54#define NFS4_ANYONE_MODE (NFS4_ACE_READ_ATTRIBUTES | NFS4_ACE_READ_ACL | NFS4_ACE_SYNCHRONIZE)
 55#define NFS4_OWNER_MODE (NFS4_ACE_WRITE_ATTRIBUTES | NFS4_ACE_WRITE_ACL)
 56
 57/* flags used to simulate posix default ACLs */
 58#define NFS4_INHERITANCE_FLAGS (NFS4_ACE_FILE_INHERIT_ACE \
 59		| NFS4_ACE_DIRECTORY_INHERIT_ACE)
 60
 61#define NFS4_SUPPORTED_FLAGS (NFS4_INHERITANCE_FLAGS \
 62		| NFS4_ACE_INHERIT_ONLY_ACE \
 63		| NFS4_ACE_IDENTIFIER_GROUP)
 64
 65static u32
 66mask_from_posix(unsigned short perm, unsigned int flags)
 67{
 68	int mask = NFS4_ANYONE_MODE;
 69
 70	if (flags & NFS4_ACL_OWNER)
 71		mask |= NFS4_OWNER_MODE;
 72	if (perm & ACL_READ)
 73		mask |= NFS4_READ_MODE;
 74	if (perm & ACL_WRITE)
 75		mask |= NFS4_WRITE_MODE;
 76	if ((perm & ACL_WRITE) && (flags & NFS4_ACL_DIR))
 77		mask |= NFS4_ACE_DELETE_CHILD;
 78	if (perm & ACL_EXECUTE)
 79		mask |= NFS4_EXECUTE_MODE;
 80	return mask;
 81}
 82
 83static u32
 84deny_mask_from_posix(unsigned short perm, u32 flags)
 85{
 86	u32 mask = 0;
 87
 88	if (perm & ACL_READ)
 89		mask |= NFS4_READ_MODE;
 90	if (perm & ACL_WRITE)
 91		mask |= NFS4_WRITE_MODE;
 92	if ((perm & ACL_WRITE) && (flags & NFS4_ACL_DIR))
 93		mask |= NFS4_ACE_DELETE_CHILD;
 94	if (perm & ACL_EXECUTE)
 95		mask |= NFS4_EXECUTE_MODE;
 96	return mask;
 97}
 98
 99/* XXX: modify functions to return NFS errors; they're only ever
100 * used by nfs code, after all.... */
101
102/* We only map from NFSv4 to POSIX ACLs when setting ACLs, when we err on the
103 * side of being more restrictive, so the mode bit mapping below is
104 * pessimistic.  An optimistic version would be needed to handle DENY's,
105 * but we expect to coalesce all ALLOWs and DENYs before mapping to mode
106 * bits. */
107
108static void
109low_mode_from_nfs4(u32 perm, unsigned short *mode, unsigned int flags)
110{
111	u32 write_mode = NFS4_WRITE_MODE;
112
113	if (flags & NFS4_ACL_DIR)
114		write_mode |= NFS4_ACE_DELETE_CHILD;
115	*mode = 0;
116	if ((perm & NFS4_READ_MODE) == NFS4_READ_MODE)
117		*mode |= ACL_READ;
118	if ((perm & write_mode) == write_mode)
119		*mode |= ACL_WRITE;
120	if ((perm & NFS4_EXECUTE_MODE) == NFS4_EXECUTE_MODE)
121		*mode |= ACL_EXECUTE;
122}
123
124static short ace2type(struct nfs4_ace *);
125static void _posix_to_nfsv4_one(struct posix_acl *, struct nfs4_acl *,
126				unsigned int);
127
128int
129nfsd4_get_nfs4_acl(struct svc_rqst *rqstp, struct dentry *dentry,
130		struct nfs4_acl **acl)
131{
132	struct inode *inode = d_inode(dentry);
133	int error = 0;
134	struct posix_acl *pacl = NULL, *dpacl = NULL;
135	unsigned int flags = 0;
136	int size = 0;
137
138	pacl = get_inode_acl(inode, ACL_TYPE_ACCESS);
139	if (!pacl)
140		pacl = posix_acl_from_mode(inode->i_mode, GFP_KERNEL);
141
142	if (IS_ERR(pacl))
143		return PTR_ERR(pacl);
144
145	/* allocate for worst case: one (deny, allow) pair each: */
146	size += 2 * pacl->a_count;
147
148	if (S_ISDIR(inode->i_mode)) {
149		flags = NFS4_ACL_DIR;
150		dpacl = get_inode_acl(inode, ACL_TYPE_DEFAULT);
151		if (IS_ERR(dpacl)) {
152			error = PTR_ERR(dpacl);
153			goto rel_pacl;
154		}
155
156		if (dpacl)
157			size += 2 * dpacl->a_count;
158	}
159
160	*acl = kmalloc(nfs4_acl_bytes(size), GFP_KERNEL);
161	if (*acl == NULL) {
162		error = -ENOMEM;
163		goto out;
164	}
165	(*acl)->naces = 0;
166
167	_posix_to_nfsv4_one(pacl, *acl, flags & ~NFS4_ACL_TYPE_DEFAULT);
168
169	if (dpacl)
170		_posix_to_nfsv4_one(dpacl, *acl, flags | NFS4_ACL_TYPE_DEFAULT);
171
172out:
173	posix_acl_release(dpacl);
174rel_pacl:
175	posix_acl_release(pacl);
176	return error;
177}
178
179struct posix_acl_summary {
180	unsigned short owner;
181	unsigned short users;
182	unsigned short group;
183	unsigned short groups;
184	unsigned short other;
185	unsigned short mask;
186};
187
188static void
189summarize_posix_acl(struct posix_acl *acl, struct posix_acl_summary *pas)
190{
191	struct posix_acl_entry *pa, *pe;
192
193	/*
194	 * Only pas.users and pas.groups need initialization; previous
195	 * posix_acl_valid() calls ensure that the other fields will be
196	 * initialized in the following loop.  But, just to placate gcc:
197	 */
198	memset(pas, 0, sizeof(*pas));
199	pas->mask = 07;
200
201	pe = acl->a_entries + acl->a_count;
202
203	FOREACH_ACL_ENTRY(pa, acl, pe) {
204		switch (pa->e_tag) {
205			case ACL_USER_OBJ:
206				pas->owner = pa->e_perm;
207				break;
208			case ACL_GROUP_OBJ:
209				pas->group = pa->e_perm;
210				break;
211			case ACL_USER:
212				pas->users |= pa->e_perm;
213				break;
214			case ACL_GROUP:
215				pas->groups |= pa->e_perm;
216				break;
217			case ACL_OTHER:
218				pas->other = pa->e_perm;
219				break;
220			case ACL_MASK:
221				pas->mask = pa->e_perm;
222				break;
223		}
224	}
225	/* We'll only care about effective permissions: */
226	pas->users &= pas->mask;
227	pas->group &= pas->mask;
228	pas->groups &= pas->mask;
229}
230
231/* We assume the acl has been verified with posix_acl_valid. */
232static void
233_posix_to_nfsv4_one(struct posix_acl *pacl, struct nfs4_acl *acl,
234						unsigned int flags)
235{
236	struct posix_acl_entry *pa, *group_owner_entry;
237	struct nfs4_ace *ace;
238	struct posix_acl_summary pas;
239	unsigned short deny;
240	int eflag = ((flags & NFS4_ACL_TYPE_DEFAULT) ?
241		NFS4_INHERITANCE_FLAGS | NFS4_ACE_INHERIT_ONLY_ACE : 0);
242
243	BUG_ON(pacl->a_count < 3);
244	summarize_posix_acl(pacl, &pas);
245
246	pa = pacl->a_entries;
247	ace = acl->aces + acl->naces;
248
249	/* We could deny everything not granted by the owner: */
250	deny = ~pas.owner;
251	/*
252	 * but it is equivalent (and simpler) to deny only what is not
253	 * granted by later entries:
254	 */
255	deny &= pas.users | pas.group | pas.groups | pas.other;
256	if (deny) {
257		ace->type = NFS4_ACE_ACCESS_DENIED_ACE_TYPE;
258		ace->flag = eflag;
259		ace->access_mask = deny_mask_from_posix(deny, flags);
260		ace->whotype = NFS4_ACL_WHO_OWNER;
261		ace++;
262		acl->naces++;
263	}
264
265	ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
266	ace->flag = eflag;
267	ace->access_mask = mask_from_posix(pa->e_perm, flags | NFS4_ACL_OWNER);
268	ace->whotype = NFS4_ACL_WHO_OWNER;
269	ace++;
270	acl->naces++;
271	pa++;
272
273	while (pa->e_tag == ACL_USER) {
274		deny = ~(pa->e_perm & pas.mask);
275		deny &= pas.groups | pas.group | pas.other;
276		if (deny) {
277			ace->type = NFS4_ACE_ACCESS_DENIED_ACE_TYPE;
278			ace->flag = eflag;
279			ace->access_mask = deny_mask_from_posix(deny, flags);
280			ace->whotype = NFS4_ACL_WHO_NAMED;
281			ace->who_uid = pa->e_uid;
282			ace++;
283			acl->naces++;
284		}
285		ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
286		ace->flag = eflag;
287		ace->access_mask = mask_from_posix(pa->e_perm & pas.mask,
288						   flags);
289		ace->whotype = NFS4_ACL_WHO_NAMED;
290		ace->who_uid = pa->e_uid;
291		ace++;
292		acl->naces++;
293		pa++;
294	}
295
296	/* In the case of groups, we apply allow ACEs first, then deny ACEs,
297	 * since a user can be in more than one group.  */
298
299	/* allow ACEs */
300
301	group_owner_entry = pa;
302
303	ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
304	ace->flag = eflag;
305	ace->access_mask = mask_from_posix(pas.group, flags);
306	ace->whotype = NFS4_ACL_WHO_GROUP;
307	ace++;
308	acl->naces++;
309	pa++;
310
311	while (pa->e_tag == ACL_GROUP) {
312		ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
313		ace->flag = eflag | NFS4_ACE_IDENTIFIER_GROUP;
314		ace->access_mask = mask_from_posix(pa->e_perm & pas.mask,
315						   flags);
316		ace->whotype = NFS4_ACL_WHO_NAMED;
317		ace->who_gid = pa->e_gid;
318		ace++;
319		acl->naces++;
320		pa++;
321	}
322
323	/* deny ACEs */
324
325	pa = group_owner_entry;
326
327	deny = ~pas.group & pas.other;
328	if (deny) {
329		ace->type = NFS4_ACE_ACCESS_DENIED_ACE_TYPE;
330		ace->flag = eflag;
331		ace->access_mask = deny_mask_from_posix(deny, flags);
332		ace->whotype = NFS4_ACL_WHO_GROUP;
333		ace++;
334		acl->naces++;
335	}
336	pa++;
337
338	while (pa->e_tag == ACL_GROUP) {
339		deny = ~(pa->e_perm & pas.mask);
340		deny &= pas.other;
341		if (deny) {
342			ace->type = NFS4_ACE_ACCESS_DENIED_ACE_TYPE;
343			ace->flag = eflag | NFS4_ACE_IDENTIFIER_GROUP;
344			ace->access_mask = deny_mask_from_posix(deny, flags);
345			ace->whotype = NFS4_ACL_WHO_NAMED;
346			ace->who_gid = pa->e_gid;
347			ace++;
348			acl->naces++;
349		}
350		pa++;
351	}
352
353	if (pa->e_tag == ACL_MASK)
354		pa++;
355	ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
356	ace->flag = eflag;
357	ace->access_mask = mask_from_posix(pa->e_perm, flags);
358	ace->whotype = NFS4_ACL_WHO_EVERYONE;
359	acl->naces++;
360}
361
362static bool
363pace_gt(struct posix_acl_entry *pace1, struct posix_acl_entry *pace2)
364{
365	if (pace1->e_tag != pace2->e_tag)
366		return pace1->e_tag > pace2->e_tag;
367	if (pace1->e_tag == ACL_USER)
368		return uid_gt(pace1->e_uid, pace2->e_uid);
369	if (pace1->e_tag == ACL_GROUP)
370		return gid_gt(pace1->e_gid, pace2->e_gid);
371	return false;
372}
373
374static void
375sort_pacl_range(struct posix_acl *pacl, int start, int end) {
376	int sorted = 0, i;
377
378	/* We just do a bubble sort; easy to do in place, and we're not
379	 * expecting acl's to be long enough to justify anything more. */
380	while (!sorted) {
381		sorted = 1;
382		for (i = start; i < end; i++) {
383			if (pace_gt(&pacl->a_entries[i],
384				    &pacl->a_entries[i+1])) {
385				sorted = 0;
386				swap(pacl->a_entries[i],
387				     pacl->a_entries[i + 1]);
388			}
389		}
390	}
391}
392
393static void
394sort_pacl(struct posix_acl *pacl)
395{
396	/* posix_acl_valid requires that users and groups be in order
397	 * by uid/gid. */
398	int i, j;
399
400	/* no users or groups */
401	if (!pacl || pacl->a_count <= 4)
402		return;
403
404	i = 1;
405	while (pacl->a_entries[i].e_tag == ACL_USER)
406		i++;
407	sort_pacl_range(pacl, 1, i-1);
408
409	BUG_ON(pacl->a_entries[i].e_tag != ACL_GROUP_OBJ);
410	j = ++i;
411	while (pacl->a_entries[j].e_tag == ACL_GROUP)
412		j++;
413	sort_pacl_range(pacl, i, j-1);
414	return;
415}
416
417/*
418 * While processing the NFSv4 ACE, this maintains bitmasks representing
419 * which permission bits have been allowed and which denied to a given
420 * entity: */
421struct posix_ace_state {
422	u32 allow;
423	u32 deny;
424};
425
426struct posix_user_ace_state {
427	union {
428		kuid_t uid;
429		kgid_t gid;
430	};
431	struct posix_ace_state perms;
432};
433
434struct posix_ace_state_array {
435	int n;
436	struct posix_user_ace_state aces[];
437};
438
439/*
440 * While processing the NFSv4 ACE, this maintains the partial permissions
441 * calculated so far: */
442
443struct posix_acl_state {
444	unsigned char valid;
445	struct posix_ace_state owner;
446	struct posix_ace_state group;
447	struct posix_ace_state other;
448	struct posix_ace_state everyone;
449	struct posix_ace_state mask; /* Deny unused in this case */
450	struct posix_ace_state_array *users;
451	struct posix_ace_state_array *groups;
452};
453
454static int
455init_state(struct posix_acl_state *state, int cnt)
456{
457	int alloc;
458
459	memset(state, 0, sizeof(struct posix_acl_state));
 
460	/*
461	 * In the worst case, each individual acl could be for a distinct
462	 * named user or group, but we don't know which, so we allocate
463	 * enough space for either:
464	 */
465	alloc = sizeof(struct posix_ace_state_array)
466		+ cnt*sizeof(struct posix_user_ace_state);
467	state->users = kzalloc(alloc, GFP_KERNEL);
468	if (!state->users)
469		return -ENOMEM;
470	state->groups = kzalloc(alloc, GFP_KERNEL);
471	if (!state->groups) {
472		kfree(state->users);
473		return -ENOMEM;
474	}
475	return 0;
476}
477
478static void
479free_state(struct posix_acl_state *state) {
480	kfree(state->users);
481	kfree(state->groups);
482}
483
484static inline void add_to_mask(struct posix_acl_state *state, struct posix_ace_state *astate)
485{
486	state->mask.allow |= astate->allow;
487}
488
489static struct posix_acl *
490posix_state_to_acl(struct posix_acl_state *state, unsigned int flags)
491{
492	struct posix_acl_entry *pace;
493	struct posix_acl *pacl;
494	int nace;
495	int i;
496
497	/*
498	 * ACLs with no ACEs are treated differently in the inheritable
499	 * and effective cases: when there are no inheritable ACEs,
500	 * calls ->set_acl with a NULL ACL structure.
501	 */
502	if (!state->valid && (flags & NFS4_ACL_TYPE_DEFAULT))
503		return NULL;
504
505	/*
506	 * When there are no effective ACEs, the following will end
507	 * up setting a 3-element effective posix ACL with all
508	 * permissions zero.
509	 */
510	if (!state->users->n && !state->groups->n)
511		nace = 3;
512	else /* Note we also include a MASK ACE in this case: */
513		nace = 4 + state->users->n + state->groups->n;
514	pacl = posix_acl_alloc(nace, GFP_KERNEL);
515	if (!pacl)
516		return ERR_PTR(-ENOMEM);
517
518	pace = pacl->a_entries;
519	pace->e_tag = ACL_USER_OBJ;
520	low_mode_from_nfs4(state->owner.allow, &pace->e_perm, flags);
521
522	for (i=0; i < state->users->n; i++) {
523		pace++;
524		pace->e_tag = ACL_USER;
525		low_mode_from_nfs4(state->users->aces[i].perms.allow,
526					&pace->e_perm, flags);
527		pace->e_uid = state->users->aces[i].uid;
528		add_to_mask(state, &state->users->aces[i].perms);
529	}
530
531	pace++;
532	pace->e_tag = ACL_GROUP_OBJ;
533	low_mode_from_nfs4(state->group.allow, &pace->e_perm, flags);
534	add_to_mask(state, &state->group);
535
536	for (i=0; i < state->groups->n; i++) {
537		pace++;
538		pace->e_tag = ACL_GROUP;
539		low_mode_from_nfs4(state->groups->aces[i].perms.allow,
540					&pace->e_perm, flags);
541		pace->e_gid = state->groups->aces[i].gid;
542		add_to_mask(state, &state->groups->aces[i].perms);
543	}
544
545	if (state->users->n || state->groups->n) {
546		pace++;
547		pace->e_tag = ACL_MASK;
548		low_mode_from_nfs4(state->mask.allow, &pace->e_perm, flags);
549	}
550
551	pace++;
552	pace->e_tag = ACL_OTHER;
553	low_mode_from_nfs4(state->other.allow, &pace->e_perm, flags);
554
555	return pacl;
556}
557
558static inline void allow_bits(struct posix_ace_state *astate, u32 mask)
559{
560	/* Allow all bits in the mask not already denied: */
561	astate->allow |= mask & ~astate->deny;
562}
563
564static inline void deny_bits(struct posix_ace_state *astate, u32 mask)
565{
566	/* Deny all bits in the mask not already allowed: */
567	astate->deny |= mask & ~astate->allow;
568}
569
570static int find_uid(struct posix_acl_state *state, kuid_t uid)
571{
572	struct posix_ace_state_array *a = state->users;
573	int i;
574
575	for (i = 0; i < a->n; i++)
576		if (uid_eq(a->aces[i].uid, uid))
577			return i;
578	/* Not found: */
579	a->n++;
580	a->aces[i].uid = uid;
581	a->aces[i].perms.allow = state->everyone.allow;
582	a->aces[i].perms.deny  = state->everyone.deny;
583
584	return i;
585}
586
587static int find_gid(struct posix_acl_state *state, kgid_t gid)
588{
589	struct posix_ace_state_array *a = state->groups;
590	int i;
591
592	for (i = 0; i < a->n; i++)
593		if (gid_eq(a->aces[i].gid, gid))
594			return i;
595	/* Not found: */
596	a->n++;
597	a->aces[i].gid = gid;
598	a->aces[i].perms.allow = state->everyone.allow;
599	a->aces[i].perms.deny  = state->everyone.deny;
600
601	return i;
602}
603
604static void deny_bits_array(struct posix_ace_state_array *a, u32 mask)
605{
606	int i;
607
608	for (i=0; i < a->n; i++)
609		deny_bits(&a->aces[i].perms, mask);
610}
611
612static void allow_bits_array(struct posix_ace_state_array *a, u32 mask)
613{
614	int i;
615
616	for (i=0; i < a->n; i++)
617		allow_bits(&a->aces[i].perms, mask);
618}
619
620static void process_one_v4_ace(struct posix_acl_state *state,
621				struct nfs4_ace *ace)
622{
623	u32 mask = ace->access_mask;
624	short type = ace2type(ace);
625	int i;
626
627	state->valid |= type;
628
629	switch (type) {
630	case ACL_USER_OBJ:
631		if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
632			allow_bits(&state->owner, mask);
633		} else {
634			deny_bits(&state->owner, mask);
635		}
636		break;
637	case ACL_USER:
638		i = find_uid(state, ace->who_uid);
639		if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
640			allow_bits(&state->users->aces[i].perms, mask);
641		} else {
642			deny_bits(&state->users->aces[i].perms, mask);
643			mask = state->users->aces[i].perms.deny;
644			deny_bits(&state->owner, mask);
645		}
646		break;
647	case ACL_GROUP_OBJ:
648		if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
649			allow_bits(&state->group, mask);
650		} else {
651			deny_bits(&state->group, mask);
652			mask = state->group.deny;
653			deny_bits(&state->owner, mask);
654			deny_bits(&state->everyone, mask);
655			deny_bits_array(state->users, mask);
656			deny_bits_array(state->groups, mask);
657		}
658		break;
659	case ACL_GROUP:
660		i = find_gid(state, ace->who_gid);
661		if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
662			allow_bits(&state->groups->aces[i].perms, mask);
663		} else {
664			deny_bits(&state->groups->aces[i].perms, mask);
665			mask = state->groups->aces[i].perms.deny;
666			deny_bits(&state->owner, mask);
667			deny_bits(&state->group, mask);
668			deny_bits(&state->everyone, mask);
669			deny_bits_array(state->users, mask);
670			deny_bits_array(state->groups, mask);
671		}
672		break;
673	case ACL_OTHER:
674		if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
675			allow_bits(&state->owner, mask);
676			allow_bits(&state->group, mask);
677			allow_bits(&state->other, mask);
678			allow_bits(&state->everyone, mask);
679			allow_bits_array(state->users, mask);
680			allow_bits_array(state->groups, mask);
681		} else {
682			deny_bits(&state->owner, mask);
683			deny_bits(&state->group, mask);
684			deny_bits(&state->other, mask);
685			deny_bits(&state->everyone, mask);
686			deny_bits_array(state->users, mask);
687			deny_bits_array(state->groups, mask);
688		}
689	}
690}
691
692static int nfs4_acl_nfsv4_to_posix(struct nfs4_acl *acl,
693		struct posix_acl **pacl, struct posix_acl **dpacl,
694		unsigned int flags)
695{
696	struct posix_acl_state effective_acl_state, default_acl_state;
697	struct nfs4_ace *ace;
698	int ret;
699
700	ret = init_state(&effective_acl_state, acl->naces);
701	if (ret)
702		return ret;
703	ret = init_state(&default_acl_state, acl->naces);
704	if (ret)
705		goto out_estate;
706	ret = -EINVAL;
707	for (ace = acl->aces; ace < acl->aces + acl->naces; ace++) {
708		if (ace->type != NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE &&
709		    ace->type != NFS4_ACE_ACCESS_DENIED_ACE_TYPE)
710			goto out_dstate;
711		if (ace->flag & ~NFS4_SUPPORTED_FLAGS)
712			goto out_dstate;
713		if ((ace->flag & NFS4_INHERITANCE_FLAGS) == 0) {
714			process_one_v4_ace(&effective_acl_state, ace);
715			continue;
716		}
717		if (!(flags & NFS4_ACL_DIR))
718			goto out_dstate;
719		/*
720		 * Note that when only one of FILE_INHERIT or DIRECTORY_INHERIT
721		 * is set, we're effectively turning on the other.  That's OK,
722		 * according to rfc 3530.
723		 */
724		process_one_v4_ace(&default_acl_state, ace);
725
726		if (!(ace->flag & NFS4_ACE_INHERIT_ONLY_ACE))
727			process_one_v4_ace(&effective_acl_state, ace);
728	}
729
730	/*
731	 * At this point, the default ACL may have zeroed-out entries for owner,
732	 * group and other. That usually results in a non-sensical resulting ACL
733	 * that denies all access except to any ACE that was explicitly added.
734	 *
735	 * The setfacl command solves a similar problem with this logic:
736	 *
737	 * "If  a  Default  ACL  entry is created, and the Default ACL contains
738	 *  no owner, owning group, or others entry,  a  copy of  the  ACL
739	 *  owner, owning group, or others entry is added to the Default ACL."
740	 *
741	 * Copy any missing ACEs from the effective set, if any ACEs were
742	 * explicitly set.
743	 */
744	if (default_acl_state.valid) {
745		if (!(default_acl_state.valid & ACL_USER_OBJ))
746			default_acl_state.owner = effective_acl_state.owner;
747		if (!(default_acl_state.valid & ACL_GROUP_OBJ))
748			default_acl_state.group = effective_acl_state.group;
749		if (!(default_acl_state.valid & ACL_OTHER))
750			default_acl_state.other = effective_acl_state.other;
751	}
752
753	*pacl = posix_state_to_acl(&effective_acl_state, flags);
754	if (IS_ERR(*pacl)) {
755		ret = PTR_ERR(*pacl);
756		*pacl = NULL;
757		goto out_dstate;
758	}
759	*dpacl = posix_state_to_acl(&default_acl_state,
760						flags | NFS4_ACL_TYPE_DEFAULT);
761	if (IS_ERR(*dpacl)) {
762		ret = PTR_ERR(*dpacl);
763		*dpacl = NULL;
764		posix_acl_release(*pacl);
765		*pacl = NULL;
766		goto out_dstate;
767	}
768	sort_pacl(*pacl);
769	sort_pacl(*dpacl);
770	ret = 0;
771out_dstate:
772	free_state(&default_acl_state);
773out_estate:
774	free_state(&effective_acl_state);
775	return ret;
776}
777
778__be32 nfsd4_acl_to_attr(enum nfs_ftype4 type, struct nfs4_acl *acl,
779			 struct nfsd_attrs *attr)
 
780{
 
781	int host_error;
 
 
 
782	unsigned int flags = 0;
783
784	if (!acl)
785		return nfs_ok;
 
 
786
787	if (type == NF4DIR)
 
 
 
788		flags = NFS4_ACL_DIR;
789
790	host_error = nfs4_acl_nfsv4_to_posix(acl, &attr->na_pacl,
791					     &attr->na_dpacl, flags);
792	if (host_error == -EINVAL)
793		return nfserr_attrnotsupp;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
794	else
795		return nfserrno(host_error);
796}
 
797
798static short
799ace2type(struct nfs4_ace *ace)
800{
801	switch (ace->whotype) {
802		case NFS4_ACL_WHO_NAMED:
803			return (ace->flag & NFS4_ACE_IDENTIFIER_GROUP ?
804					ACL_GROUP : ACL_USER);
805		case NFS4_ACL_WHO_OWNER:
806			return ACL_USER_OBJ;
807		case NFS4_ACL_WHO_GROUP:
808			return ACL_GROUP_OBJ;
809		case NFS4_ACL_WHO_EVERYONE:
810			return ACL_OTHER;
811	}
812	BUG();
813	return -1;
814}
815
816/*
817 * return the size of the struct nfs4_acl required to represent an acl
818 * with @entries entries.
819 */
820int nfs4_acl_bytes(int entries)
821{
822	return sizeof(struct nfs4_acl) + entries * sizeof(struct nfs4_ace);
823}
824
825static struct {
826	char *string;
827	int   stringlen;
828	int type;
829} s2t_map[] = {
830	{
831		.string    = "OWNER@",
832		.stringlen = sizeof("OWNER@") - 1,
833		.type      = NFS4_ACL_WHO_OWNER,
834	},
835	{
836		.string    = "GROUP@",
837		.stringlen = sizeof("GROUP@") - 1,
838		.type      = NFS4_ACL_WHO_GROUP,
839	},
840	{
841		.string    = "EVERYONE@",
842		.stringlen = sizeof("EVERYONE@") - 1,
843		.type      = NFS4_ACL_WHO_EVERYONE,
844	},
845};
846
847int
848nfs4_acl_get_whotype(char *p, u32 len)
849{
850	int i;
851
852	for (i = 0; i < ARRAY_SIZE(s2t_map); i++) {
853		if (s2t_map[i].stringlen == len &&
854				0 == memcmp(s2t_map[i].string, p, len))
855			return s2t_map[i].type;
856	}
857	return NFS4_ACL_WHO_NAMED;
858}
859
860__be32 nfs4_acl_write_who(struct xdr_stream *xdr, int who)
861{
862	__be32 *p;
863	int i;
864
865	for (i = 0; i < ARRAY_SIZE(s2t_map); i++) {
866		if (s2t_map[i].type != who)
867			continue;
868		p = xdr_reserve_space(xdr, s2t_map[i].stringlen + 4);
869		if (!p)
870			return nfserr_resource;
871		p = xdr_encode_opaque(p, s2t_map[i].string,
872					s2t_map[i].stringlen);
873		return 0;
874	}
875	WARN_ON_ONCE(1);
876	return nfserr_serverfault;
877}