Loading...
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
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 espect 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
124struct ace_container {
125 struct nfs4_ace *ace;
126 struct list_head ace_l;
127};
128
129static short ace2type(struct nfs4_ace *);
130static void _posix_to_nfsv4_one(struct posix_acl *, struct nfs4_acl *,
131 unsigned int);
132
133struct nfs4_acl *
134nfs4_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
165struct 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
174static void
175summarize_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. */
218static 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
348static void
349sort_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
369static void
370sort_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: */
395struct posix_ace_state {
396 u32 allow;
397 u32 deny;
398};
399
400struct posix_user_ace_state {
401 uid_t uid;
402 struct posix_ace_state perms;
403};
404
405struct 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
414struct 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
425static int
426init_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
450static void
451free_state(struct posix_acl_state *state) {
452 kfree(state->users);
453 kfree(state->groups);
454}
455
456static 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
480static 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
491static struct posix_acl *
492posix_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;
573out_err:
574 posix_acl_release(pacl);
575 return ERR_PTR(error);
576}
577
578static 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
584static 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
590static 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
606static 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
614static 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
622static 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
693int 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;
747out_dstate:
748 free_state(&default_acl_state);
749out_estate:
750 free_state(&effective_acl_state);
751 return ret;
752}
753
754static short
755ace2type(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
772EXPORT_SYMBOL(nfs4_acl_posix_to_nfsv4);
773EXPORT_SYMBOL(nfs4_acl_nfsv4_to_posix);
774
775struct nfs4_acl *
776nfs4_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
787static 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
809int
810nfs4_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
822int
823nfs4_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
837EXPORT_SYMBOL(nfs4_acl_new);
838EXPORT_SYMBOL(nfs4_acl_get_whotype);
839EXPORT_SYMBOL(nfs4_acl_write_who);
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 "acl.h"
40
41
42/* mode bit translations: */
43#define NFS4_READ_MODE (NFS4_ACE_READ_DATA)
44#define NFS4_WRITE_MODE (NFS4_ACE_WRITE_DATA | NFS4_ACE_APPEND_DATA)
45#define NFS4_EXECUTE_MODE NFS4_ACE_EXECUTE
46#define NFS4_ANYONE_MODE (NFS4_ACE_READ_ATTRIBUTES | NFS4_ACE_READ_ACL | NFS4_ACE_SYNCHRONIZE)
47#define NFS4_OWNER_MODE (NFS4_ACE_WRITE_ATTRIBUTES | NFS4_ACE_WRITE_ACL)
48
49/* We don't support these bits; insist they be neither allowed nor denied */
50#define NFS4_MASK_UNSUPP (NFS4_ACE_DELETE | NFS4_ACE_WRITE_OWNER \
51 | NFS4_ACE_READ_NAMED_ATTRS | NFS4_ACE_WRITE_NAMED_ATTRS)
52
53/* flags used to simulate posix default ACLs */
54#define NFS4_INHERITANCE_FLAGS (NFS4_ACE_FILE_INHERIT_ACE \
55 | NFS4_ACE_DIRECTORY_INHERIT_ACE)
56
57#define NFS4_SUPPORTED_FLAGS (NFS4_INHERITANCE_FLAGS \
58 | NFS4_ACE_INHERIT_ONLY_ACE \
59 | NFS4_ACE_IDENTIFIER_GROUP)
60
61#define MASK_EQUAL(mask1, mask2) \
62 ( ((mask1) & NFS4_ACE_MASK_ALL) == ((mask2) & NFS4_ACE_MASK_ALL) )
63
64static u32
65mask_from_posix(unsigned short perm, unsigned int flags)
66{
67 int mask = NFS4_ANYONE_MODE;
68
69 if (flags & NFS4_ACL_OWNER)
70 mask |= NFS4_OWNER_MODE;
71 if (perm & ACL_READ)
72 mask |= NFS4_READ_MODE;
73 if (perm & ACL_WRITE)
74 mask |= NFS4_WRITE_MODE;
75 if ((perm & ACL_WRITE) && (flags & NFS4_ACL_DIR))
76 mask |= NFS4_ACE_DELETE_CHILD;
77 if (perm & ACL_EXECUTE)
78 mask |= NFS4_EXECUTE_MODE;
79 return mask;
80}
81
82static u32
83deny_mask_from_posix(unsigned short perm, u32 flags)
84{
85 u32 mask = 0;
86
87 if (perm & ACL_READ)
88 mask |= NFS4_READ_MODE;
89 if (perm & ACL_WRITE)
90 mask |= NFS4_WRITE_MODE;
91 if ((perm & ACL_WRITE) && (flags & NFS4_ACL_DIR))
92 mask |= NFS4_ACE_DELETE_CHILD;
93 if (perm & ACL_EXECUTE)
94 mask |= NFS4_EXECUTE_MODE;
95 return mask;
96}
97
98/* XXX: modify functions to return NFS errors; they're only ever
99 * used by nfs code, after all.... */
100
101/* We only map from NFSv4 to POSIX ACLs when setting ACLs, when we err on the
102 * side of being more restrictive, so the mode bit mapping below is
103 * pessimistic. An optimistic version would be needed to handle DENY's,
104 * but we espect to coalesce all ALLOWs and DENYs before mapping to mode
105 * bits. */
106
107static void
108low_mode_from_nfs4(u32 perm, unsigned short *mode, unsigned int flags)
109{
110 u32 write_mode = NFS4_WRITE_MODE;
111
112 if (flags & NFS4_ACL_DIR)
113 write_mode |= NFS4_ACE_DELETE_CHILD;
114 *mode = 0;
115 if ((perm & NFS4_READ_MODE) == NFS4_READ_MODE)
116 *mode |= ACL_READ;
117 if ((perm & write_mode) == write_mode)
118 *mode |= ACL_WRITE;
119 if ((perm & NFS4_EXECUTE_MODE) == NFS4_EXECUTE_MODE)
120 *mode |= ACL_EXECUTE;
121}
122
123struct ace_container {
124 struct nfs4_ace *ace;
125 struct list_head ace_l;
126};
127
128static short ace2type(struct nfs4_ace *);
129static void _posix_to_nfsv4_one(struct posix_acl *, struct nfs4_acl *,
130 unsigned int);
131
132struct nfs4_acl *
133nfs4_acl_posix_to_nfsv4(struct posix_acl *pacl, struct posix_acl *dpacl,
134 unsigned int flags)
135{
136 struct nfs4_acl *acl;
137 int size = 0;
138
139 if (pacl) {
140 if (posix_acl_valid(pacl) < 0)
141 return ERR_PTR(-EINVAL);
142 size += 2*pacl->a_count;
143 }
144 if (dpacl) {
145 if (posix_acl_valid(dpacl) < 0)
146 return ERR_PTR(-EINVAL);
147 size += 2*dpacl->a_count;
148 }
149
150 /* Allocate for worst case: one (deny, allow) pair each: */
151 acl = nfs4_acl_new(size);
152 if (acl == NULL)
153 return ERR_PTR(-ENOMEM);
154
155 if (pacl)
156 _posix_to_nfsv4_one(pacl, acl, flags & ~NFS4_ACL_TYPE_DEFAULT);
157
158 if (dpacl)
159 _posix_to_nfsv4_one(dpacl, acl, flags | NFS4_ACL_TYPE_DEFAULT);
160
161 return acl;
162}
163
164struct posix_acl_summary {
165 unsigned short owner;
166 unsigned short users;
167 unsigned short group;
168 unsigned short groups;
169 unsigned short other;
170 unsigned short mask;
171};
172
173static void
174summarize_posix_acl(struct posix_acl *acl, struct posix_acl_summary *pas)
175{
176 struct posix_acl_entry *pa, *pe;
177
178 /*
179 * Only pas.users and pas.groups need initialization; previous
180 * posix_acl_valid() calls ensure that the other fields will be
181 * initialized in the following loop. But, just to placate gcc:
182 */
183 memset(pas, 0, sizeof(*pas));
184 pas->mask = 07;
185
186 pe = acl->a_entries + acl->a_count;
187
188 FOREACH_ACL_ENTRY(pa, acl, pe) {
189 switch (pa->e_tag) {
190 case ACL_USER_OBJ:
191 pas->owner = pa->e_perm;
192 break;
193 case ACL_GROUP_OBJ:
194 pas->group = pa->e_perm;
195 break;
196 case ACL_USER:
197 pas->users |= pa->e_perm;
198 break;
199 case ACL_GROUP:
200 pas->groups |= pa->e_perm;
201 break;
202 case ACL_OTHER:
203 pas->other = pa->e_perm;
204 break;
205 case ACL_MASK:
206 pas->mask = pa->e_perm;
207 break;
208 }
209 }
210 /* We'll only care about effective permissions: */
211 pas->users &= pas->mask;
212 pas->group &= pas->mask;
213 pas->groups &= pas->mask;
214}
215
216/* We assume the acl has been verified with posix_acl_valid. */
217static void
218_posix_to_nfsv4_one(struct posix_acl *pacl, struct nfs4_acl *acl,
219 unsigned int flags)
220{
221 struct posix_acl_entry *pa, *group_owner_entry;
222 struct nfs4_ace *ace;
223 struct posix_acl_summary pas;
224 unsigned short deny;
225 int eflag = ((flags & NFS4_ACL_TYPE_DEFAULT) ?
226 NFS4_INHERITANCE_FLAGS | NFS4_ACE_INHERIT_ONLY_ACE : 0);
227
228 BUG_ON(pacl->a_count < 3);
229 summarize_posix_acl(pacl, &pas);
230
231 pa = pacl->a_entries;
232 ace = acl->aces + acl->naces;
233
234 /* We could deny everything not granted by the owner: */
235 deny = ~pas.owner;
236 /*
237 * but it is equivalent (and simpler) to deny only what is not
238 * granted by later entries:
239 */
240 deny &= pas.users | pas.group | pas.groups | pas.other;
241 if (deny) {
242 ace->type = NFS4_ACE_ACCESS_DENIED_ACE_TYPE;
243 ace->flag = eflag;
244 ace->access_mask = deny_mask_from_posix(deny, flags);
245 ace->whotype = NFS4_ACL_WHO_OWNER;
246 ace++;
247 acl->naces++;
248 }
249
250 ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
251 ace->flag = eflag;
252 ace->access_mask = mask_from_posix(pa->e_perm, flags | NFS4_ACL_OWNER);
253 ace->whotype = NFS4_ACL_WHO_OWNER;
254 ace++;
255 acl->naces++;
256 pa++;
257
258 while (pa->e_tag == ACL_USER) {
259 deny = ~(pa->e_perm & pas.mask);
260 deny &= pas.groups | pas.group | pas.other;
261 if (deny) {
262 ace->type = NFS4_ACE_ACCESS_DENIED_ACE_TYPE;
263 ace->flag = eflag;
264 ace->access_mask = deny_mask_from_posix(deny, flags);
265 ace->whotype = NFS4_ACL_WHO_NAMED;
266 ace->who = pa->e_id;
267 ace++;
268 acl->naces++;
269 }
270 ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
271 ace->flag = eflag;
272 ace->access_mask = mask_from_posix(pa->e_perm & pas.mask,
273 flags);
274 ace->whotype = NFS4_ACL_WHO_NAMED;
275 ace->who = pa->e_id;
276 ace++;
277 acl->naces++;
278 pa++;
279 }
280
281 /* In the case of groups, we apply allow ACEs first, then deny ACEs,
282 * since a user can be in more than one group. */
283
284 /* allow ACEs */
285
286 group_owner_entry = pa;
287
288 ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
289 ace->flag = eflag;
290 ace->access_mask = mask_from_posix(pas.group, flags);
291 ace->whotype = NFS4_ACL_WHO_GROUP;
292 ace++;
293 acl->naces++;
294 pa++;
295
296 while (pa->e_tag == ACL_GROUP) {
297 ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
298 ace->flag = eflag | NFS4_ACE_IDENTIFIER_GROUP;
299 ace->access_mask = mask_from_posix(pa->e_perm & pas.mask,
300 flags);
301 ace->whotype = NFS4_ACL_WHO_NAMED;
302 ace->who = pa->e_id;
303 ace++;
304 acl->naces++;
305 pa++;
306 }
307
308 /* deny ACEs */
309
310 pa = group_owner_entry;
311
312 deny = ~pas.group & pas.other;
313 if (deny) {
314 ace->type = NFS4_ACE_ACCESS_DENIED_ACE_TYPE;
315 ace->flag = eflag;
316 ace->access_mask = deny_mask_from_posix(deny, flags);
317 ace->whotype = NFS4_ACL_WHO_GROUP;
318 ace++;
319 acl->naces++;
320 }
321 pa++;
322
323 while (pa->e_tag == ACL_GROUP) {
324 deny = ~(pa->e_perm & pas.mask);
325 deny &= pas.other;
326 if (deny) {
327 ace->type = NFS4_ACE_ACCESS_DENIED_ACE_TYPE;
328 ace->flag = eflag | NFS4_ACE_IDENTIFIER_GROUP;
329 ace->access_mask = deny_mask_from_posix(deny, flags);
330 ace->whotype = NFS4_ACL_WHO_NAMED;
331 ace->who = pa->e_id;
332 ace++;
333 acl->naces++;
334 }
335 pa++;
336 }
337
338 if (pa->e_tag == ACL_MASK)
339 pa++;
340 ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
341 ace->flag = eflag;
342 ace->access_mask = mask_from_posix(pa->e_perm, flags);
343 ace->whotype = NFS4_ACL_WHO_EVERYONE;
344 acl->naces++;
345}
346
347static void
348sort_pacl_range(struct posix_acl *pacl, int start, int end) {
349 int sorted = 0, i;
350 struct posix_acl_entry tmp;
351
352 /* We just do a bubble sort; easy to do in place, and we're not
353 * expecting acl's to be long enough to justify anything more. */
354 while (!sorted) {
355 sorted = 1;
356 for (i = start; i < end; i++) {
357 if (pacl->a_entries[i].e_id
358 > pacl->a_entries[i+1].e_id) {
359 sorted = 0;
360 tmp = pacl->a_entries[i];
361 pacl->a_entries[i] = pacl->a_entries[i+1];
362 pacl->a_entries[i+1] = tmp;
363 }
364 }
365 }
366}
367
368static void
369sort_pacl(struct posix_acl *pacl)
370{
371 /* posix_acl_valid requires that users and groups be in order
372 * by uid/gid. */
373 int i, j;
374
375 if (pacl->a_count <= 4)
376 return; /* no users or groups */
377 i = 1;
378 while (pacl->a_entries[i].e_tag == ACL_USER)
379 i++;
380 sort_pacl_range(pacl, 1, i-1);
381
382 BUG_ON(pacl->a_entries[i].e_tag != ACL_GROUP_OBJ);
383 j = ++i;
384 while (pacl->a_entries[j].e_tag == ACL_GROUP)
385 j++;
386 sort_pacl_range(pacl, i, j-1);
387 return;
388}
389
390/*
391 * While processing the NFSv4 ACE, this maintains bitmasks representing
392 * which permission bits have been allowed and which denied to a given
393 * entity: */
394struct posix_ace_state {
395 u32 allow;
396 u32 deny;
397};
398
399struct posix_user_ace_state {
400 uid_t uid;
401 struct posix_ace_state perms;
402};
403
404struct posix_ace_state_array {
405 int n;
406 struct posix_user_ace_state aces[];
407};
408
409/*
410 * While processing the NFSv4 ACE, this maintains the partial permissions
411 * calculated so far: */
412
413struct posix_acl_state {
414 int empty;
415 struct posix_ace_state owner;
416 struct posix_ace_state group;
417 struct posix_ace_state other;
418 struct posix_ace_state everyone;
419 struct posix_ace_state mask; /* Deny unused in this case */
420 struct posix_ace_state_array *users;
421 struct posix_ace_state_array *groups;
422};
423
424static int
425init_state(struct posix_acl_state *state, int cnt)
426{
427 int alloc;
428
429 memset(state, 0, sizeof(struct posix_acl_state));
430 state->empty = 1;
431 /*
432 * In the worst case, each individual acl could be for a distinct
433 * named user or group, but we don't no which, so we allocate
434 * enough space for either:
435 */
436 alloc = sizeof(struct posix_ace_state_array)
437 + cnt*sizeof(struct posix_user_ace_state);
438 state->users = kzalloc(alloc, GFP_KERNEL);
439 if (!state->users)
440 return -ENOMEM;
441 state->groups = kzalloc(alloc, GFP_KERNEL);
442 if (!state->groups) {
443 kfree(state->users);
444 return -ENOMEM;
445 }
446 return 0;
447}
448
449static void
450free_state(struct posix_acl_state *state) {
451 kfree(state->users);
452 kfree(state->groups);
453}
454
455static inline void add_to_mask(struct posix_acl_state *state, struct posix_ace_state *astate)
456{
457 state->mask.allow |= astate->allow;
458}
459
460/*
461 * Certain bits (SYNCHRONIZE, DELETE, WRITE_OWNER, READ/WRITE_NAMED_ATTRS,
462 * READ_ATTRIBUTES, READ_ACL) are currently unenforceable and don't translate
463 * to traditional read/write/execute permissions.
464 *
465 * It's problematic to reject acls that use certain mode bits, because it
466 * places the burden on users to learn the rules about which bits one
467 * particular server sets, without giving the user a lot of help--we return an
468 * error that could mean any number of different things. To make matters
469 * worse, the problematic bits might be introduced by some application that's
470 * automatically mapping from some other acl model.
471 *
472 * So wherever possible we accept anything, possibly erring on the side of
473 * denying more permissions than necessary.
474 *
475 * However we do reject *explicit* DENY's of a few bits representing
476 * permissions we could never deny:
477 */
478
479static inline int check_deny(u32 mask, int isowner)
480{
481 if (mask & (NFS4_ACE_READ_ATTRIBUTES | NFS4_ACE_READ_ACL))
482 return -EINVAL;
483 if (!isowner)
484 return 0;
485 if (mask & (NFS4_ACE_WRITE_ATTRIBUTES | NFS4_ACE_WRITE_ACL))
486 return -EINVAL;
487 return 0;
488}
489
490static struct posix_acl *
491posix_state_to_acl(struct posix_acl_state *state, unsigned int flags)
492{
493 struct posix_acl_entry *pace;
494 struct posix_acl *pacl;
495 int nace;
496 int i, error = 0;
497
498 /*
499 * ACLs with no ACEs are treated differently in the inheritable
500 * and effective cases: when there are no inheritable ACEs, we
501 * set a zero-length default posix acl:
502 */
503 if (state->empty && (flags & NFS4_ACL_TYPE_DEFAULT)) {
504 pacl = posix_acl_alloc(0, GFP_KERNEL);
505 return pacl ? pacl : ERR_PTR(-ENOMEM);
506 }
507 /*
508 * When there are no effective ACEs, the following will end
509 * up setting a 3-element effective posix ACL with all
510 * permissions zero.
511 */
512 nace = 4 + state->users->n + state->groups->n;
513 pacl = posix_acl_alloc(nace, GFP_KERNEL);
514 if (!pacl)
515 return ERR_PTR(-ENOMEM);
516
517 pace = pacl->a_entries;
518 pace->e_tag = ACL_USER_OBJ;
519 error = check_deny(state->owner.deny, 1);
520 if (error)
521 goto out_err;
522 low_mode_from_nfs4(state->owner.allow, &pace->e_perm, flags);
523 pace->e_id = ACL_UNDEFINED_ID;
524
525 for (i=0; i < state->users->n; i++) {
526 pace++;
527 pace->e_tag = ACL_USER;
528 error = check_deny(state->users->aces[i].perms.deny, 0);
529 if (error)
530 goto out_err;
531 low_mode_from_nfs4(state->users->aces[i].perms.allow,
532 &pace->e_perm, flags);
533 pace->e_id = state->users->aces[i].uid;
534 add_to_mask(state, &state->users->aces[i].perms);
535 }
536
537 pace++;
538 pace->e_tag = ACL_GROUP_OBJ;
539 error = check_deny(state->group.deny, 0);
540 if (error)
541 goto out_err;
542 low_mode_from_nfs4(state->group.allow, &pace->e_perm, flags);
543 pace->e_id = ACL_UNDEFINED_ID;
544 add_to_mask(state, &state->group);
545
546 for (i=0; i < state->groups->n; i++) {
547 pace++;
548 pace->e_tag = ACL_GROUP;
549 error = check_deny(state->groups->aces[i].perms.deny, 0);
550 if (error)
551 goto out_err;
552 low_mode_from_nfs4(state->groups->aces[i].perms.allow,
553 &pace->e_perm, flags);
554 pace->e_id = state->groups->aces[i].uid;
555 add_to_mask(state, &state->groups->aces[i].perms);
556 }
557
558 pace++;
559 pace->e_tag = ACL_MASK;
560 low_mode_from_nfs4(state->mask.allow, &pace->e_perm, flags);
561 pace->e_id = ACL_UNDEFINED_ID;
562
563 pace++;
564 pace->e_tag = ACL_OTHER;
565 error = check_deny(state->other.deny, 0);
566 if (error)
567 goto out_err;
568 low_mode_from_nfs4(state->other.allow, &pace->e_perm, flags);
569 pace->e_id = ACL_UNDEFINED_ID;
570
571 return pacl;
572out_err:
573 posix_acl_release(pacl);
574 return ERR_PTR(error);
575}
576
577static inline void allow_bits(struct posix_ace_state *astate, u32 mask)
578{
579 /* Allow all bits in the mask not already denied: */
580 astate->allow |= mask & ~astate->deny;
581}
582
583static inline void deny_bits(struct posix_ace_state *astate, u32 mask)
584{
585 /* Deny all bits in the mask not already allowed: */
586 astate->deny |= mask & ~astate->allow;
587}
588
589static int find_uid(struct posix_acl_state *state, struct posix_ace_state_array *a, uid_t uid)
590{
591 int i;
592
593 for (i = 0; i < a->n; i++)
594 if (a->aces[i].uid == uid)
595 return i;
596 /* Not found: */
597 a->n++;
598 a->aces[i].uid = uid;
599 a->aces[i].perms.allow = state->everyone.allow;
600 a->aces[i].perms.deny = state->everyone.deny;
601
602 return i;
603}
604
605static void deny_bits_array(struct posix_ace_state_array *a, u32 mask)
606{
607 int i;
608
609 for (i=0; i < a->n; i++)
610 deny_bits(&a->aces[i].perms, mask);
611}
612
613static void allow_bits_array(struct posix_ace_state_array *a, u32 mask)
614{
615 int i;
616
617 for (i=0; i < a->n; i++)
618 allow_bits(&a->aces[i].perms, mask);
619}
620
621static void process_one_v4_ace(struct posix_acl_state *state,
622 struct nfs4_ace *ace)
623{
624 u32 mask = ace->access_mask;
625 int i;
626
627 state->empty = 0;
628
629 switch (ace2type(ace)) {
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, state->users, ace->who);
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_uid(state, state->groups, ace->who);
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
692int nfs4_acl_nfsv4_to_posix(struct nfs4_acl *acl, struct posix_acl **pacl,
693 struct posix_acl **dpacl, unsigned int flags)
694{
695 struct posix_acl_state effective_acl_state, default_acl_state;
696 struct nfs4_ace *ace;
697 int ret;
698
699 ret = init_state(&effective_acl_state, acl->naces);
700 if (ret)
701 return ret;
702 ret = init_state(&default_acl_state, acl->naces);
703 if (ret)
704 goto out_estate;
705 ret = -EINVAL;
706 for (ace = acl->aces; ace < acl->aces + acl->naces; ace++) {
707 if (ace->type != NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE &&
708 ace->type != NFS4_ACE_ACCESS_DENIED_ACE_TYPE)
709 goto out_dstate;
710 if (ace->flag & ~NFS4_SUPPORTED_FLAGS)
711 goto out_dstate;
712 if ((ace->flag & NFS4_INHERITANCE_FLAGS) == 0) {
713 process_one_v4_ace(&effective_acl_state, ace);
714 continue;
715 }
716 if (!(flags & NFS4_ACL_DIR))
717 goto out_dstate;
718 /*
719 * Note that when only one of FILE_INHERIT or DIRECTORY_INHERIT
720 * is set, we're effectively turning on the other. That's OK,
721 * according to rfc 3530.
722 */
723 process_one_v4_ace(&default_acl_state, ace);
724
725 if (!(ace->flag & NFS4_ACE_INHERIT_ONLY_ACE))
726 process_one_v4_ace(&effective_acl_state, ace);
727 }
728 *pacl = posix_state_to_acl(&effective_acl_state, flags);
729 if (IS_ERR(*pacl)) {
730 ret = PTR_ERR(*pacl);
731 *pacl = NULL;
732 goto out_dstate;
733 }
734 *dpacl = posix_state_to_acl(&default_acl_state,
735 flags | NFS4_ACL_TYPE_DEFAULT);
736 if (IS_ERR(*dpacl)) {
737 ret = PTR_ERR(*dpacl);
738 *dpacl = NULL;
739 posix_acl_release(*pacl);
740 *pacl = NULL;
741 goto out_dstate;
742 }
743 sort_pacl(*pacl);
744 sort_pacl(*dpacl);
745 ret = 0;
746out_dstate:
747 free_state(&default_acl_state);
748out_estate:
749 free_state(&effective_acl_state);
750 return ret;
751}
752
753static short
754ace2type(struct nfs4_ace *ace)
755{
756 switch (ace->whotype) {
757 case NFS4_ACL_WHO_NAMED:
758 return (ace->flag & NFS4_ACE_IDENTIFIER_GROUP ?
759 ACL_GROUP : ACL_USER);
760 case NFS4_ACL_WHO_OWNER:
761 return ACL_USER_OBJ;
762 case NFS4_ACL_WHO_GROUP:
763 return ACL_GROUP_OBJ;
764 case NFS4_ACL_WHO_EVERYONE:
765 return ACL_OTHER;
766 }
767 BUG();
768 return -1;
769}
770
771EXPORT_SYMBOL(nfs4_acl_posix_to_nfsv4);
772EXPORT_SYMBOL(nfs4_acl_nfsv4_to_posix);
773
774struct nfs4_acl *
775nfs4_acl_new(int n)
776{
777 struct nfs4_acl *acl;
778
779 acl = kmalloc(sizeof(*acl) + n*sizeof(struct nfs4_ace), GFP_KERNEL);
780 if (acl == NULL)
781 return NULL;
782 acl->naces = 0;
783 return acl;
784}
785
786static struct {
787 char *string;
788 int stringlen;
789 int type;
790} s2t_map[] = {
791 {
792 .string = "OWNER@",
793 .stringlen = sizeof("OWNER@") - 1,
794 .type = NFS4_ACL_WHO_OWNER,
795 },
796 {
797 .string = "GROUP@",
798 .stringlen = sizeof("GROUP@") - 1,
799 .type = NFS4_ACL_WHO_GROUP,
800 },
801 {
802 .string = "EVERYONE@",
803 .stringlen = sizeof("EVERYONE@") - 1,
804 .type = NFS4_ACL_WHO_EVERYONE,
805 },
806};
807
808int
809nfs4_acl_get_whotype(char *p, u32 len)
810{
811 int i;
812
813 for (i = 0; i < ARRAY_SIZE(s2t_map); i++) {
814 if (s2t_map[i].stringlen == len &&
815 0 == memcmp(s2t_map[i].string, p, len))
816 return s2t_map[i].type;
817 }
818 return NFS4_ACL_WHO_NAMED;
819}
820
821int
822nfs4_acl_write_who(int who, char *p)
823{
824 int i;
825
826 for (i = 0; i < ARRAY_SIZE(s2t_map); i++) {
827 if (s2t_map[i].type == who) {
828 memcpy(p, s2t_map[i].string, s2t_map[i].stringlen);
829 return s2t_map[i].stringlen;
830 }
831 }
832 BUG();
833 return -1;
834}
835
836EXPORT_SYMBOL(nfs4_acl_new);
837EXPORT_SYMBOL(nfs4_acl_get_whotype);
838EXPORT_SYMBOL(nfs4_acl_write_who);