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Linux/fs/nfsd/nfs4acl.c

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  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/slab.h>
 38 #include <linux/nfs_fs.h>
 39 #include <linux/export.h>
 40 #include "acl.h"
 41 
 42 
 43 /* mode bit translations: */
 44 #define NFS4_READ_MODE (NFS4_ACE_READ_DATA)
 45 #define NFS4_WRITE_MODE (NFS4_ACE_WRITE_DATA | NFS4_ACE_APPEND_DATA)
 46 #define NFS4_EXECUTE_MODE NFS4_ACE_EXECUTE
 47 #define NFS4_ANYONE_MODE (NFS4_ACE_READ_ATTRIBUTES | NFS4_ACE_READ_ACL | NFS4_ACE_SYNCHRONIZE)
 48 #define NFS4_OWNER_MODE (NFS4_ACE_WRITE_ATTRIBUTES | NFS4_ACE_WRITE_ACL)
 49 
 50 /* We don't support these bits; insist they be neither allowed nor denied */
 51 #define NFS4_MASK_UNSUPP (NFS4_ACE_DELETE | NFS4_ACE_WRITE_OWNER \
 52                 | NFS4_ACE_READ_NAMED_ATTRS | NFS4_ACE_WRITE_NAMED_ATTRS)
 53 
 54 /* flags used to simulate posix default ACLs */
 55 #define NFS4_INHERITANCE_FLAGS (NFS4_ACE_FILE_INHERIT_ACE \
 56                 | NFS4_ACE_DIRECTORY_INHERIT_ACE)
 57 
 58 #define NFS4_SUPPORTED_FLAGS (NFS4_INHERITANCE_FLAGS \
 59                 | NFS4_ACE_INHERIT_ONLY_ACE \
 60                 | NFS4_ACE_IDENTIFIER_GROUP)
 61 
 62 #define MASK_EQUAL(mask1, mask2) \
 63         ( ((mask1) & NFS4_ACE_MASK_ALL) == ((mask2) & NFS4_ACE_MASK_ALL) )
 64 
 65 static u32
 66 mask_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 
 83 static u32
 84 deny_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 espect to coalesce all ALLOWs and DENYs before mapping to mode
106  * bits. */
107 
108 static void
109 low_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 
124 struct ace_container {
125         struct nfs4_ace  *ace;
126         struct list_head  ace_l;
127 };
128 
129 static short ace2type(struct nfs4_ace *);
130 static void _posix_to_nfsv4_one(struct posix_acl *, struct nfs4_acl *,
131                                 unsigned int);
132 
133 struct nfs4_acl *
134 nfs4_acl_posix_to_nfsv4(struct posix_acl *pacl, struct posix_acl *dpacl,
135                         unsigned int flags)
136 {
137         struct nfs4_acl *acl;
138         int size = 0;
139 
140         if (pacl) {
141                 if (posix_acl_valid(pacl) < 0)
142                         return ERR_PTR(-EINVAL);
143                 size += 2*pacl->a_count;
144         }
145         if (dpacl) {
146                 if (posix_acl_valid(dpacl) < 0)
147                         return ERR_PTR(-EINVAL);
148                 size += 2*dpacl->a_count;
149         }
150 
151         /* Allocate for worst case: one (deny, allow) pair each: */
152         acl = nfs4_acl_new(size);
153         if (acl == NULL)
154                 return ERR_PTR(-ENOMEM);
155 
156         if (pacl)
157                 _posix_to_nfsv4_one(pacl, acl, flags & ~NFS4_ACL_TYPE_DEFAULT);
158 
159         if (dpacl)
160                 _posix_to_nfsv4_one(dpacl, acl, flags | NFS4_ACL_TYPE_DEFAULT);
161 
162         return acl;
163 }
164 
165 struct posix_acl_summary {
166         unsigned short owner;
167         unsigned short users;
168         unsigned short group;
169         unsigned short groups;
170         unsigned short other;
171         unsigned short mask;
172 };
173 
174 static void
175 summarize_posix_acl(struct posix_acl *acl, struct posix_acl_summary *pas)
176 {
177         struct posix_acl_entry *pa, *pe;
178 
179         /*
180          * Only pas.users and pas.groups need initialization; previous
181          * posix_acl_valid() calls ensure that the other fields will be
182          * initialized in the following loop.  But, just to placate gcc:
183          */
184         memset(pas, 0, sizeof(*pas));
185         pas->mask = 07;
186 
187         pe = acl->a_entries + acl->a_count;
188 
189         FOREACH_ACL_ENTRY(pa, acl, pe) {
190                 switch (pa->e_tag) {
191                         case ACL_USER_OBJ:
192                                 pas->owner = pa->e_perm;
193                                 break;
194                         case ACL_GROUP_OBJ:
195                                 pas->group = pa->e_perm;
196                                 break;
197                         case ACL_USER:
198                                 pas->users |= pa->e_perm;
199                                 break;
200                         case ACL_GROUP:
201                                 pas->groups |= pa->e_perm;
202                                 break;
203                         case ACL_OTHER:
204                                 pas->other = pa->e_perm;
205                                 break;
206                         case ACL_MASK:
207                                 pas->mask = pa->e_perm;
208                                 break;
209                 }
210         }
211         /* We'll only care about effective permissions: */
212         pas->users &= pas->mask;
213         pas->group &= pas->mask;
214         pas->groups &= pas->mask;
215 }
216 
217 /* We assume the acl has been verified with posix_acl_valid. */
218 static void
219 _posix_to_nfsv4_one(struct posix_acl *pacl, struct nfs4_acl *acl,
220                                                 unsigned int flags)
221 {
222         struct posix_acl_entry *pa, *group_owner_entry;
223         struct nfs4_ace *ace;
224         struct posix_acl_summary pas;
225         unsigned short deny;
226         int eflag = ((flags & NFS4_ACL_TYPE_DEFAULT) ?
227                 NFS4_INHERITANCE_FLAGS | NFS4_ACE_INHERIT_ONLY_ACE : 0);
228 
229         BUG_ON(pacl->a_count < 3);
230         summarize_posix_acl(pacl, &pas);
231 
232         pa = pacl->a_entries;
233         ace = acl->aces + acl->naces;
234 
235         /* We could deny everything not granted by the owner: */
236         deny = ~pas.owner;
237         /*
238          * but it is equivalent (and simpler) to deny only what is not
239          * granted by later entries:
240          */
241         deny &= pas.users | pas.group | pas.groups | pas.other;
242         if (deny) {
243                 ace->type = NFS4_ACE_ACCESS_DENIED_ACE_TYPE;
244                 ace->flag = eflag;
245                 ace->access_mask = deny_mask_from_posix(deny, flags);
246                 ace->whotype = NFS4_ACL_WHO_OWNER;
247                 ace++;
248                 acl->naces++;
249         }
250 
251         ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
252         ace->flag = eflag;
253         ace->access_mask = mask_from_posix(pa->e_perm, flags | NFS4_ACL_OWNER);
254         ace->whotype = NFS4_ACL_WHO_OWNER;
255         ace++;
256         acl->naces++;
257         pa++;
258 
259         while (pa->e_tag == ACL_USER) {
260                 deny = ~(pa->e_perm & pas.mask);
261                 deny &= pas.groups | pas.group | pas.other;
262                 if (deny) {
263                         ace->type = NFS4_ACE_ACCESS_DENIED_ACE_TYPE;
264                         ace->flag = eflag;
265                         ace->access_mask = deny_mask_from_posix(deny, flags);
266                         ace->whotype = NFS4_ACL_WHO_NAMED;
267                         ace->who = pa->e_id;
268                         ace++;
269                         acl->naces++;
270                 }
271                 ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
272                 ace->flag = eflag;
273                 ace->access_mask = mask_from_posix(pa->e_perm & pas.mask,
274                                                    flags);
275                 ace->whotype = NFS4_ACL_WHO_NAMED;
276                 ace->who = pa->e_id;
277                 ace++;
278                 acl->naces++;
279                 pa++;
280         }
281 
282         /* In the case of groups, we apply allow ACEs first, then deny ACEs,
283          * since a user can be in more than one group.  */
284 
285         /* allow ACEs */
286 
287         group_owner_entry = pa;
288 
289         ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
290         ace->flag = eflag;
291         ace->access_mask = mask_from_posix(pas.group, flags);
292         ace->whotype = NFS4_ACL_WHO_GROUP;
293         ace++;
294         acl->naces++;
295         pa++;
296 
297         while (pa->e_tag == ACL_GROUP) {
298                 ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
299                 ace->flag = eflag | NFS4_ACE_IDENTIFIER_GROUP;
300                 ace->access_mask = mask_from_posix(pa->e_perm & pas.mask,
301                                                    flags);
302                 ace->whotype = NFS4_ACL_WHO_NAMED;
303                 ace->who = pa->e_id;
304                 ace++;
305                 acl->naces++;
306                 pa++;
307         }
308 
309         /* deny ACEs */
310 
311         pa = group_owner_entry;
312 
313         deny = ~pas.group & pas.other;
314         if (deny) {
315                 ace->type = NFS4_ACE_ACCESS_DENIED_ACE_TYPE;
316                 ace->flag = eflag;
317                 ace->access_mask = deny_mask_from_posix(deny, flags);
318                 ace->whotype = NFS4_ACL_WHO_GROUP;
319                 ace++;
320                 acl->naces++;
321         }
322         pa++;
323 
324         while (pa->e_tag == ACL_GROUP) {
325                 deny = ~(pa->e_perm & pas.mask);
326                 deny &= pas.other;
327                 if (deny) {
328                         ace->type = NFS4_ACE_ACCESS_DENIED_ACE_TYPE;
329                         ace->flag = eflag | NFS4_ACE_IDENTIFIER_GROUP;
330                         ace->access_mask = deny_mask_from_posix(deny, flags);
331                         ace->whotype = NFS4_ACL_WHO_NAMED;
332                         ace->who = pa->e_id;
333                         ace++;
334                         acl->naces++;
335                 }
336                 pa++;
337         }
338 
339         if (pa->e_tag == ACL_MASK)
340                 pa++;
341         ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
342         ace->flag = eflag;
343         ace->access_mask = mask_from_posix(pa->e_perm, flags);
344         ace->whotype = NFS4_ACL_WHO_EVERYONE;
345         acl->naces++;
346 }
347 
348 static void
349 sort_pacl_range(struct posix_acl *pacl, int start, int end) {
350         int sorted = 0, i;
351         struct posix_acl_entry tmp;
352 
353         /* We just do a bubble sort; easy to do in place, and we're not
354          * expecting acl's to be long enough to justify anything more. */
355         while (!sorted) {
356                 sorted = 1;
357                 for (i = start; i < end; i++) {
358                         if (pacl->a_entries[i].e_id
359                                         > pacl->a_entries[i+1].e_id) {
360                                 sorted = 0;
361                                 tmp = pacl->a_entries[i];
362                                 pacl->a_entries[i] = pacl->a_entries[i+1];
363                                 pacl->a_entries[i+1] = tmp;
364                         }
365                 }
366         }
367 }
368 
369 static void
370 sort_pacl(struct posix_acl *pacl)
371 {
372         /* posix_acl_valid requires that users and groups be in order
373          * by uid/gid. */
374         int i, j;
375 
376         if (pacl->a_count <= 4)
377                 return; /* no users or groups */
378         i = 1;
379         while (pacl->a_entries[i].e_tag == ACL_USER)
380                 i++;
381         sort_pacl_range(pacl, 1, i-1);
382 
383         BUG_ON(pacl->a_entries[i].e_tag != ACL_GROUP_OBJ);
384         j = ++i;
385         while (pacl->a_entries[j].e_tag == ACL_GROUP)
386                 j++;
387         sort_pacl_range(pacl, i, j-1);
388         return;
389 }
390 
391 /*
392  * While processing the NFSv4 ACE, this maintains bitmasks representing
393  * which permission bits have been allowed and which denied to a given
394  * entity: */
395 struct posix_ace_state {
396         u32 allow;
397         u32 deny;
398 };
399 
400 struct posix_user_ace_state {
401         uid_t uid;
402         struct posix_ace_state perms;
403 };
404 
405 struct posix_ace_state_array {
406         int n;
407         struct posix_user_ace_state aces[];
408 };
409 
410 /*
411  * While processing the NFSv4 ACE, this maintains the partial permissions
412  * calculated so far: */
413 
414 struct posix_acl_state {
415         int empty;
416         struct posix_ace_state owner;
417         struct posix_ace_state group;
418         struct posix_ace_state other;
419         struct posix_ace_state everyone;
420         struct posix_ace_state mask; /* Deny unused in this case */
421         struct posix_ace_state_array *users;
422         struct posix_ace_state_array *groups;
423 };
424 
425 static int
426 init_state(struct posix_acl_state *state, int cnt)
427 {
428         int alloc;
429 
430         memset(state, 0, sizeof(struct posix_acl_state));
431         state->empty = 1;
432         /*
433          * In the worst case, each individual acl could be for a distinct
434          * named user or group, but we don't no which, so we allocate
435          * enough space for either:
436          */
437         alloc = sizeof(struct posix_ace_state_array)
438                 + cnt*sizeof(struct posix_user_ace_state);
439         state->users = kzalloc(alloc, GFP_KERNEL);
440         if (!state->users)
441                 return -ENOMEM;
442         state->groups = kzalloc(alloc, GFP_KERNEL);
443         if (!state->groups) {
444                 kfree(state->users);
445                 return -ENOMEM;
446         }
447         return 0;
448 }
449 
450 static void
451 free_state(struct posix_acl_state *state) {
452         kfree(state->users);
453         kfree(state->groups);
454 }
455 
456 static inline void add_to_mask(struct posix_acl_state *state, struct posix_ace_state *astate)
457 {
458         state->mask.allow |= astate->allow;
459 }
460 
461 /*
462  * Certain bits (SYNCHRONIZE, DELETE, WRITE_OWNER, READ/WRITE_NAMED_ATTRS,
463  * READ_ATTRIBUTES, READ_ACL) are currently unenforceable and don't translate
464  * to traditional read/write/execute permissions.
465  *
466  * It's problematic to reject acls that use certain mode bits, because it
467  * places the burden on users to learn the rules about which bits one
468  * particular server sets, without giving the user a lot of help--we return an
469  * error that could mean any number of different things.  To make matters
470  * worse, the problematic bits might be introduced by some application that's
471  * automatically mapping from some other acl model.
472  *
473  * So wherever possible we accept anything, possibly erring on the side of
474  * denying more permissions than necessary.
475  *
476  * However we do reject *explicit* DENY's of a few bits representing
477  * permissions we could never deny:
478  */
479 
480 static inline int check_deny(u32 mask, int isowner)
481 {
482         if (mask & (NFS4_ACE_READ_ATTRIBUTES | NFS4_ACE_READ_ACL))
483                 return -EINVAL;
484         if (!isowner)
485                 return 0;
486         if (mask & (NFS4_ACE_WRITE_ATTRIBUTES | NFS4_ACE_WRITE_ACL))
487                 return -EINVAL;
488         return 0;
489 }
490 
491 static struct posix_acl *
492 posix_state_to_acl(struct posix_acl_state *state, unsigned int flags)
493 {
494         struct posix_acl_entry *pace;
495         struct posix_acl *pacl;
496         int nace;
497         int i, error = 0;
498 
499         /*
500          * ACLs with no ACEs are treated differently in the inheritable
501          * and effective cases: when there are no inheritable ACEs, we
502          * set a zero-length default posix acl:
503          */
504         if (state->empty && (flags & NFS4_ACL_TYPE_DEFAULT)) {
505                 pacl = posix_acl_alloc(0, GFP_KERNEL);
506                 return pacl ? pacl : ERR_PTR(-ENOMEM);
507         }
508         /*
509          * When there are no effective ACEs, the following will end
510          * up setting a 3-element effective posix ACL with all
511          * permissions zero.
512          */
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         error = check_deny(state->owner.deny, 1);
521         if (error)
522                 goto out_err;
523         low_mode_from_nfs4(state->owner.allow, &pace->e_perm, flags);
524         pace->e_id = ACL_UNDEFINED_ID;
525 
526         for (i=0; i < state->users->n; i++) {
527                 pace++;
528                 pace->e_tag = ACL_USER;
529                 error = check_deny(state->users->aces[i].perms.deny, 0);
530                 if (error)
531                         goto out_err;
532                 low_mode_from_nfs4(state->users->aces[i].perms.allow,
533                                         &pace->e_perm, flags);
534                 pace->e_id = state->users->aces[i].uid;
535                 add_to_mask(state, &state->users->aces[i].perms);
536         }
537 
538         pace++;
539         pace->e_tag = ACL_GROUP_OBJ;
540         error = check_deny(state->group.deny, 0);
541         if (error)
542                 goto out_err;
543         low_mode_from_nfs4(state->group.allow, &pace->e_perm, flags);
544         pace->e_id = ACL_UNDEFINED_ID;
545         add_to_mask(state, &state->group);
546 
547         for (i=0; i < state->groups->n; i++) {
548                 pace++;
549                 pace->e_tag = ACL_GROUP;
550                 error = check_deny(state->groups->aces[i].perms.deny, 0);
551                 if (error)
552                         goto out_err;
553                 low_mode_from_nfs4(state->groups->aces[i].perms.allow,
554                                         &pace->e_perm, flags);
555                 pace->e_id = state->groups->aces[i].uid;
556                 add_to_mask(state, &state->groups->aces[i].perms);
557         }
558 
559         pace++;
560         pace->e_tag = ACL_MASK;
561         low_mode_from_nfs4(state->mask.allow, &pace->e_perm, flags);
562         pace->e_id = ACL_UNDEFINED_ID;
563 
564         pace++;
565         pace->e_tag = ACL_OTHER;
566         error = check_deny(state->other.deny, 0);
567         if (error)
568                 goto out_err;
569         low_mode_from_nfs4(state->other.allow, &pace->e_perm, flags);
570         pace->e_id = ACL_UNDEFINED_ID;
571 
572         return pacl;
573 out_err:
574         posix_acl_release(pacl);
575         return ERR_PTR(error);
576 }
577 
578 static inline void allow_bits(struct posix_ace_state *astate, u32 mask)
579 {
580         /* Allow all bits in the mask not already denied: */
581         astate->allow |= mask & ~astate->deny;
582 }
583 
584 static inline void deny_bits(struct posix_ace_state *astate, u32 mask)
585 {
586         /* Deny all bits in the mask not already allowed: */
587         astate->deny |= mask & ~astate->allow;
588 }
589 
590 static int find_uid(struct posix_acl_state *state, struct posix_ace_state_array *a, uid_t uid)
591 {
592         int i;
593 
594         for (i = 0; i < a->n; i++)
595                 if (a->aces[i].uid == uid)
596                         return i;
597         /* Not found: */
598         a->n++;
599         a->aces[i].uid = uid;
600         a->aces[i].perms.allow = state->everyone.allow;
601         a->aces[i].perms.deny  = state->everyone.deny;
602 
603         return i;
604 }
605 
606 static void deny_bits_array(struct posix_ace_state_array *a, u32 mask)
607 {
608         int i;
609 
610         for (i=0; i < a->n; i++)
611                 deny_bits(&a->aces[i].perms, mask);
612 }
613 
614 static void allow_bits_array(struct posix_ace_state_array *a, u32 mask)
615 {
616         int i;
617 
618         for (i=0; i < a->n; i++)
619                 allow_bits(&a->aces[i].perms, mask);
620 }
621 
622 static void process_one_v4_ace(struct posix_acl_state *state,
623                                 struct nfs4_ace *ace)
624 {
625         u32 mask = ace->access_mask;
626         int i;
627 
628         state->empty = 0;
629 
630         switch (ace2type(ace)) {
631         case ACL_USER_OBJ:
632                 if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
633                         allow_bits(&state->owner, mask);
634                 } else {
635                         deny_bits(&state->owner, mask);
636                 }
637                 break;
638         case ACL_USER:
639                 i = find_uid(state, state->users, ace->who);
640                 if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
641                         allow_bits(&state->users->aces[i].perms, mask);
642                 } else {
643                         deny_bits(&state->users->aces[i].perms, mask);
644                         mask = state->users->aces[i].perms.deny;
645                         deny_bits(&state->owner, mask);
646                 }
647                 break;
648         case ACL_GROUP_OBJ:
649                 if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
650                         allow_bits(&state->group, mask);
651                 } else {
652                         deny_bits(&state->group, mask);
653                         mask = state->group.deny;
654                         deny_bits(&state->owner, mask);
655                         deny_bits(&state->everyone, mask);
656                         deny_bits_array(state->users, mask);
657                         deny_bits_array(state->groups, mask);
658                 }
659                 break;
660         case ACL_GROUP:
661                 i = find_uid(state, state->groups, ace->who);
662                 if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
663                         allow_bits(&state->groups->aces[i].perms, mask);
664                 } else {
665                         deny_bits(&state->groups->aces[i].perms, mask);
666                         mask = state->groups->aces[i].perms.deny;
667                         deny_bits(&state->owner, mask);
668                         deny_bits(&state->group, mask);
669                         deny_bits(&state->everyone, mask);
670                         deny_bits_array(state->users, mask);
671                         deny_bits_array(state->groups, mask);
672                 }
673                 break;
674         case ACL_OTHER:
675                 if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
676                         allow_bits(&state->owner, mask);
677                         allow_bits(&state->group, mask);
678                         allow_bits(&state->other, mask);
679                         allow_bits(&state->everyone, mask);
680                         allow_bits_array(state->users, mask);
681                         allow_bits_array(state->groups, mask);
682                 } else {
683                         deny_bits(&state->owner, mask);
684                         deny_bits(&state->group, mask);
685                         deny_bits(&state->other, mask);
686                         deny_bits(&state->everyone, mask);
687                         deny_bits_array(state->users, mask);
688                         deny_bits_array(state->groups, mask);
689                 }
690         }
691 }
692 
693 int nfs4_acl_nfsv4_to_posix(struct nfs4_acl *acl, struct posix_acl **pacl,
694                             struct posix_acl **dpacl, 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         *pacl = posix_state_to_acl(&effective_acl_state, flags);
730         if (IS_ERR(*pacl)) {
731                 ret = PTR_ERR(*pacl);
732                 *pacl = NULL;
733                 goto out_dstate;
734         }
735         *dpacl = posix_state_to_acl(&default_acl_state,
736                                                 flags | NFS4_ACL_TYPE_DEFAULT);
737         if (IS_ERR(*dpacl)) {
738                 ret = PTR_ERR(*dpacl);
739                 *dpacl = NULL;
740                 posix_acl_release(*pacl);
741                 *pacl = NULL;
742                 goto out_dstate;
743         }
744         sort_pacl(*pacl);
745         sort_pacl(*dpacl);
746         ret = 0;
747 out_dstate:
748         free_state(&default_acl_state);
749 out_estate:
750         free_state(&effective_acl_state);
751         return ret;
752 }
753 
754 static short
755 ace2type(struct nfs4_ace *ace)
756 {
757         switch (ace->whotype) {
758                 case NFS4_ACL_WHO_NAMED:
759                         return (ace->flag & NFS4_ACE_IDENTIFIER_GROUP ?
760                                         ACL_GROUP : ACL_USER);
761                 case NFS4_ACL_WHO_OWNER:
762                         return ACL_USER_OBJ;
763                 case NFS4_ACL_WHO_GROUP:
764                         return ACL_GROUP_OBJ;
765                 case NFS4_ACL_WHO_EVERYONE:
766                         return ACL_OTHER;
767         }
768         BUG();
769         return -1;
770 }
771 
772 EXPORT_SYMBOL(nfs4_acl_posix_to_nfsv4);
773 EXPORT_SYMBOL(nfs4_acl_nfsv4_to_posix);
774 
775 struct nfs4_acl *
776 nfs4_acl_new(int n)
777 {
778         struct nfs4_acl *acl;
779 
780         acl = kmalloc(sizeof(*acl) + n*sizeof(struct nfs4_ace), GFP_KERNEL);
781         if (acl == NULL)
782                 return NULL;
783         acl->naces = 0;
784         return acl;
785 }
786 
787 static struct {
788         char *string;
789         int   stringlen;
790         int type;
791 } s2t_map[] = {
792         {
793                 .string    = "OWNER@",
794                 .stringlen = sizeof("OWNER@") - 1,
795                 .type      = NFS4_ACL_WHO_OWNER,
796         },
797         {
798                 .string    = "GROUP@",
799                 .stringlen = sizeof("GROUP@") - 1,
800                 .type      = NFS4_ACL_WHO_GROUP,
801         },
802         {
803                 .string    = "EVERYONE@",
804                 .stringlen = sizeof("EVERYONE@") - 1,
805                 .type      = NFS4_ACL_WHO_EVERYONE,
806         },
807 };
808 
809 int
810 nfs4_acl_get_whotype(char *p, u32 len)
811 {
812         int i;
813 
814         for (i = 0; i < ARRAY_SIZE(s2t_map); i++) {
815                 if (s2t_map[i].stringlen == len &&
816                                 0 == memcmp(s2t_map[i].string, p, len))
817                         return s2t_map[i].type;
818         }
819         return NFS4_ACL_WHO_NAMED;
820 }
821 
822 int
823 nfs4_acl_write_who(int who, char *p)
824 {
825         int i;
826 
827         for (i = 0; i < ARRAY_SIZE(s2t_map); i++) {
828                 if (s2t_map[i].type == who) {
829                         memcpy(p, s2t_map[i].string, s2t_map[i].stringlen);
830                         return s2t_map[i].stringlen;
831                 }
832         }
833         BUG();
834         return -1;
835 }
836 
837 EXPORT_SYMBOL(nfs4_acl_new);
838 EXPORT_SYMBOL(nfs4_acl_get_whotype);
839 EXPORT_SYMBOL(nfs4_acl_write_who);
840 

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