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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/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 FOREACH_ACL_ENTRY(pa, acl, pe) {
202 switch (pa->e_tag) {
203 case ACL_USER_OBJ:
204 pas->owner = pa->e_perm;
205 break;
206 case ACL_GROUP_OBJ:
207 pas->group = pa->e_perm;
208 break;
209 case ACL_USER:
210 pas->users |= pa->e_perm;
211 break;
212 case ACL_GROUP:
213 pas->groups |= pa->e_perm;
214 break;
215 case ACL_OTHER:
216 pas->other = pa->e_perm;
217 break;
218 case ACL_MASK:
219 pas->mask = pa->e_perm;
220 break;
221 }
222 }
223 /* We'll only care about effective permissions: */
224 pas->users &= pas->mask;
225 pas->group &= pas->mask;
226 pas->groups &= pas->mask;
227}
228
229/* We assume the acl has been verified with posix_acl_valid. */
230static void
231_posix_to_nfsv4_one(struct posix_acl *pacl, struct nfs4_acl *acl,
232 unsigned int flags)
233{
234 struct posix_acl_entry *pa, *group_owner_entry;
235 struct nfs4_ace *ace;
236 struct posix_acl_summary pas;
237 unsigned short deny;
238 int eflag = ((flags & NFS4_ACL_TYPE_DEFAULT) ?
239 NFS4_INHERITANCE_FLAGS | NFS4_ACE_INHERIT_ONLY_ACE : 0);
240
241 BUG_ON(pacl->a_count < 3);
242 summarize_posix_acl(pacl, &pas);
243
244 pa = pacl->a_entries;
245 ace = acl->aces + acl->naces;
246
247 /* We could deny everything not granted by the owner: */
248 deny = ~pas.owner;
249 /*
250 * but it is equivalent (and simpler) to deny only what is not
251 * granted by later entries:
252 */
253 deny &= pas.users | pas.group | pas.groups | pas.other;
254 if (deny) {
255 ace->type = NFS4_ACE_ACCESS_DENIED_ACE_TYPE;
256 ace->flag = eflag;
257 ace->access_mask = deny_mask_from_posix(deny, flags);
258 ace->whotype = NFS4_ACL_WHO_OWNER;
259 ace++;
260 acl->naces++;
261 }
262
263 ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
264 ace->flag = eflag;
265 ace->access_mask = mask_from_posix(pa->e_perm, flags | NFS4_ACL_OWNER);
266 ace->whotype = NFS4_ACL_WHO_OWNER;
267 ace++;
268 acl->naces++;
269 pa++;
270
271 while (pa->e_tag == ACL_USER) {
272 deny = ~(pa->e_perm & pas.mask);
273 deny &= pas.groups | pas.group | pas.other;
274 if (deny) {
275 ace->type = NFS4_ACE_ACCESS_DENIED_ACE_TYPE;
276 ace->flag = eflag;
277 ace->access_mask = deny_mask_from_posix(deny, flags);
278 ace->whotype = NFS4_ACL_WHO_NAMED;
279 ace->who_uid = pa->e_uid;
280 ace++;
281 acl->naces++;
282 }
283 ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
284 ace->flag = eflag;
285 ace->access_mask = mask_from_posix(pa->e_perm & pas.mask,
286 flags);
287 ace->whotype = NFS4_ACL_WHO_NAMED;
288 ace->who_uid = pa->e_uid;
289 ace++;
290 acl->naces++;
291 pa++;
292 }
293
294 /* In the case of groups, we apply allow ACEs first, then deny ACEs,
295 * since a user can be in more than one group. */
296
297 /* allow ACEs */
298
299 group_owner_entry = pa;
300
301 ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
302 ace->flag = eflag;
303 ace->access_mask = mask_from_posix(pas.group, flags);
304 ace->whotype = NFS4_ACL_WHO_GROUP;
305 ace++;
306 acl->naces++;
307 pa++;
308
309 while (pa->e_tag == ACL_GROUP) {
310 ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
311 ace->flag = eflag | NFS4_ACE_IDENTIFIER_GROUP;
312 ace->access_mask = mask_from_posix(pa->e_perm & pas.mask,
313 flags);
314 ace->whotype = NFS4_ACL_WHO_NAMED;
315 ace->who_gid = pa->e_gid;
316 ace++;
317 acl->naces++;
318 pa++;
319 }
320
321 /* deny ACEs */
322
323 pa = group_owner_entry;
324
325 deny = ~pas.group & pas.other;
326 if (deny) {
327 ace->type = NFS4_ACE_ACCESS_DENIED_ACE_TYPE;
328 ace->flag = eflag;
329 ace->access_mask = deny_mask_from_posix(deny, flags);
330 ace->whotype = NFS4_ACL_WHO_GROUP;
331 ace++;
332 acl->naces++;
333 }
334 pa++;
335
336 while (pa->e_tag == ACL_GROUP) {
337 deny = ~(pa->e_perm & pas.mask);
338 deny &= pas.other;
339 if (deny) {
340 ace->type = NFS4_ACE_ACCESS_DENIED_ACE_TYPE;
341 ace->flag = eflag | NFS4_ACE_IDENTIFIER_GROUP;
342 ace->access_mask = deny_mask_from_posix(deny, flags);
343 ace->whotype = NFS4_ACL_WHO_NAMED;
344 ace->who_gid = pa->e_gid;
345 ace++;
346 acl->naces++;
347 }
348 pa++;
349 }
350
351 if (pa->e_tag == ACL_MASK)
352 pa++;
353 ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
354 ace->flag = eflag;
355 ace->access_mask = mask_from_posix(pa->e_perm, flags);
356 ace->whotype = NFS4_ACL_WHO_EVERYONE;
357 acl->naces++;
358}
359
360static bool
361pace_gt(struct posix_acl_entry *pace1, struct posix_acl_entry *pace2)
362{
363 if (pace1->e_tag != pace2->e_tag)
364 return pace1->e_tag > pace2->e_tag;
365 if (pace1->e_tag == ACL_USER)
366 return uid_gt(pace1->e_uid, pace2->e_uid);
367 if (pace1->e_tag == ACL_GROUP)
368 return gid_gt(pace1->e_gid, pace2->e_gid);
369 return false;
370}
371
372static void
373sort_pacl_range(struct posix_acl *pacl, int start, int end) {
374 int sorted = 0, i;
375
376 /* We just do a bubble sort; easy to do in place, and we're not
377 * expecting acl's to be long enough to justify anything more. */
378 while (!sorted) {
379 sorted = 1;
380 for (i = start; i < end; i++) {
381 if (pace_gt(&pacl->a_entries[i],
382 &pacl->a_entries[i+1])) {
383 sorted = 0;
384 swap(pacl->a_entries[i],
385 pacl->a_entries[i + 1]);
386 }
387 }
388 }
389}
390
391static void
392sort_pacl(struct posix_acl *pacl)
393{
394 /* posix_acl_valid requires that users and groups be in order
395 * by uid/gid. */
396 int i, j;
397
398 /* no users or groups */
399 if (!pacl || pacl->a_count <= 4)
400 return;
401
402 i = 1;
403 while (pacl->a_entries[i].e_tag == ACL_USER)
404 i++;
405 sort_pacl_range(pacl, 1, i-1);
406
407 BUG_ON(pacl->a_entries[i].e_tag != ACL_GROUP_OBJ);
408 j = ++i;
409 while (pacl->a_entries[j].e_tag == ACL_GROUP)
410 j++;
411 sort_pacl_range(pacl, i, j-1);
412 return;
413}
414
415/*
416 * While processing the NFSv4 ACE, this maintains bitmasks representing
417 * which permission bits have been allowed and which denied to a given
418 * entity: */
419struct posix_ace_state {
420 u32 allow;
421 u32 deny;
422};
423
424struct posix_user_ace_state {
425 union {
426 kuid_t uid;
427 kgid_t gid;
428 };
429 struct posix_ace_state perms;
430};
431
432struct posix_ace_state_array {
433 int n;
434 struct posix_user_ace_state aces[];
435};
436
437/*
438 * While processing the NFSv4 ACE, this maintains the partial permissions
439 * calculated so far: */
440
441struct posix_acl_state {
442 unsigned char valid;
443 struct posix_ace_state owner;
444 struct posix_ace_state group;
445 struct posix_ace_state other;
446 struct posix_ace_state everyone;
447 struct posix_ace_state mask; /* Deny unused in this case */
448 struct posix_ace_state_array *users;
449 struct posix_ace_state_array *groups;
450};
451
452static int
453init_state(struct posix_acl_state *state, int cnt)
454{
455 int alloc;
456
457 memset(state, 0, sizeof(struct posix_acl_state));
458 /*
459 * In the worst case, each individual acl could be for a distinct
460 * named user or group, but we don't know which, so we allocate
461 * enough space for either:
462 */
463 alloc = sizeof(struct posix_ace_state_array)
464 + cnt*sizeof(struct posix_user_ace_state);
465 state->users = kzalloc(alloc, GFP_KERNEL);
466 if (!state->users)
467 return -ENOMEM;
468 state->groups = kzalloc(alloc, GFP_KERNEL);
469 if (!state->groups) {
470 kfree(state->users);
471 return -ENOMEM;
472 }
473 return 0;
474}
475
476static void
477free_state(struct posix_acl_state *state) {
478 kfree(state->users);
479 kfree(state->groups);
480}
481
482static inline void add_to_mask(struct posix_acl_state *state, struct posix_ace_state *astate)
483{
484 state->mask.allow |= astate->allow;
485}
486
487static struct posix_acl *
488posix_state_to_acl(struct posix_acl_state *state, unsigned int flags)
489{
490 struct posix_acl_entry *pace;
491 struct posix_acl *pacl;
492 int nace;
493 int i;
494
495 /*
496 * ACLs with no ACEs are treated differently in the inheritable
497 * and effective cases: when there are no inheritable ACEs,
498 * calls ->set_acl with a NULL ACL structure.
499 */
500 if (!state->valid && (flags & NFS4_ACL_TYPE_DEFAULT))
501 return NULL;
502
503 /*
504 * When there are no effective ACEs, the following will end
505 * up setting a 3-element effective posix ACL with all
506 * permissions zero.
507 */
508 if (!state->users->n && !state->groups->n)
509 nace = 3;
510 else /* Note we also include a MASK ACE in this case: */
511 nace = 4 + state->users->n + state->groups->n;
512 pacl = posix_acl_alloc(nace, GFP_KERNEL);
513 if (!pacl)
514 return ERR_PTR(-ENOMEM);
515
516 pace = pacl->a_entries;
517 pace->e_tag = ACL_USER_OBJ;
518 low_mode_from_nfs4(state->owner.allow, &pace->e_perm, flags);
519
520 for (i=0; i < state->users->n; i++) {
521 pace++;
522 pace->e_tag = ACL_USER;
523 low_mode_from_nfs4(state->users->aces[i].perms.allow,
524 &pace->e_perm, flags);
525 pace->e_uid = state->users->aces[i].uid;
526 add_to_mask(state, &state->users->aces[i].perms);
527 }
528
529 pace++;
530 pace->e_tag = ACL_GROUP_OBJ;
531 low_mode_from_nfs4(state->group.allow, &pace->e_perm, flags);
532 add_to_mask(state, &state->group);
533
534 for (i=0; i < state->groups->n; i++) {
535 pace++;
536 pace->e_tag = ACL_GROUP;
537 low_mode_from_nfs4(state->groups->aces[i].perms.allow,
538 &pace->e_perm, flags);
539 pace->e_gid = state->groups->aces[i].gid;
540 add_to_mask(state, &state->groups->aces[i].perms);
541 }
542
543 if (state->users->n || state->groups->n) {
544 pace++;
545 pace->e_tag = ACL_MASK;
546 low_mode_from_nfs4(state->mask.allow, &pace->e_perm, flags);
547 }
548
549 pace++;
550 pace->e_tag = ACL_OTHER;
551 low_mode_from_nfs4(state->other.allow, &pace->e_perm, flags);
552
553 return pacl;
554}
555
556static inline void allow_bits(struct posix_ace_state *astate, u32 mask)
557{
558 /* Allow all bits in the mask not already denied: */
559 astate->allow |= mask & ~astate->deny;
560}
561
562static inline void deny_bits(struct posix_ace_state *astate, u32 mask)
563{
564 /* Deny all bits in the mask not already allowed: */
565 astate->deny |= mask & ~astate->allow;
566}
567
568static int find_uid(struct posix_acl_state *state, kuid_t uid)
569{
570 struct posix_ace_state_array *a = state->users;
571 int i;
572
573 for (i = 0; i < a->n; i++)
574 if (uid_eq(a->aces[i].uid, uid))
575 return i;
576 /* Not found: */
577 a->n++;
578 a->aces[i].uid = uid;
579 a->aces[i].perms.allow = state->everyone.allow;
580 a->aces[i].perms.deny = state->everyone.deny;
581
582 return i;
583}
584
585static int find_gid(struct posix_acl_state *state, kgid_t gid)
586{
587 struct posix_ace_state_array *a = state->groups;
588 int i;
589
590 for (i = 0; i < a->n; i++)
591 if (gid_eq(a->aces[i].gid, gid))
592 return i;
593 /* Not found: */
594 a->n++;
595 a->aces[i].gid = gid;
596 a->aces[i].perms.allow = state->everyone.allow;
597 a->aces[i].perms.deny = state->everyone.deny;
598
599 return i;
600}
601
602static void deny_bits_array(struct posix_ace_state_array *a, u32 mask)
603{
604 int i;
605
606 for (i=0; i < a->n; i++)
607 deny_bits(&a->aces[i].perms, mask);
608}
609
610static void allow_bits_array(struct posix_ace_state_array *a, u32 mask)
611{
612 int i;
613
614 for (i=0; i < a->n; i++)
615 allow_bits(&a->aces[i].perms, mask);
616}
617
618static void process_one_v4_ace(struct posix_acl_state *state,
619 struct nfs4_ace *ace)
620{
621 u32 mask = ace->access_mask;
622 short type = ace2type(ace);
623 int i;
624
625 state->valid |= type;
626
627 switch (type) {
628 case ACL_USER_OBJ:
629 if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
630 allow_bits(&state->owner, mask);
631 } else {
632 deny_bits(&state->owner, mask);
633 }
634 break;
635 case ACL_USER:
636 i = find_uid(state, ace->who_uid);
637 if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
638 allow_bits(&state->users->aces[i].perms, mask);
639 } else {
640 deny_bits(&state->users->aces[i].perms, mask);
641 mask = state->users->aces[i].perms.deny;
642 deny_bits(&state->owner, mask);
643 }
644 break;
645 case ACL_GROUP_OBJ:
646 if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
647 allow_bits(&state->group, mask);
648 } else {
649 deny_bits(&state->group, mask);
650 mask = state->group.deny;
651 deny_bits(&state->owner, mask);
652 deny_bits(&state->everyone, mask);
653 deny_bits_array(state->users, mask);
654 deny_bits_array(state->groups, mask);
655 }
656 break;
657 case ACL_GROUP:
658 i = find_gid(state, ace->who_gid);
659 if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
660 allow_bits(&state->groups->aces[i].perms, mask);
661 } else {
662 deny_bits(&state->groups->aces[i].perms, mask);
663 mask = state->groups->aces[i].perms.deny;
664 deny_bits(&state->owner, mask);
665 deny_bits(&state->group, mask);
666 deny_bits(&state->everyone, mask);
667 deny_bits_array(state->users, mask);
668 deny_bits_array(state->groups, mask);
669 }
670 break;
671 case ACL_OTHER:
672 if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
673 allow_bits(&state->owner, mask);
674 allow_bits(&state->group, mask);
675 allow_bits(&state->other, mask);
676 allow_bits(&state->everyone, mask);
677 allow_bits_array(state->users, mask);
678 allow_bits_array(state->groups, mask);
679 } else {
680 deny_bits(&state->owner, mask);
681 deny_bits(&state->group, mask);
682 deny_bits(&state->other, mask);
683 deny_bits(&state->everyone, mask);
684 deny_bits_array(state->users, mask);
685 deny_bits_array(state->groups, mask);
686 }
687 }
688}
689
690static int nfs4_acl_nfsv4_to_posix(struct nfs4_acl *acl,
691 struct posix_acl **pacl, struct posix_acl **dpacl,
692 unsigned int flags)
693{
694 struct posix_acl_state effective_acl_state, default_acl_state;
695 struct nfs4_ace *ace;
696 int ret;
697
698 ret = init_state(&effective_acl_state, acl->naces);
699 if (ret)
700 return ret;
701 ret = init_state(&default_acl_state, acl->naces);
702 if (ret)
703 goto out_estate;
704 ret = -EINVAL;
705 for (ace = acl->aces; ace < acl->aces + acl->naces; ace++) {
706 if (ace->type != NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE &&
707 ace->type != NFS4_ACE_ACCESS_DENIED_ACE_TYPE)
708 goto out_dstate;
709 if (ace->flag & ~NFS4_SUPPORTED_FLAGS)
710 goto out_dstate;
711 if ((ace->flag & NFS4_INHERITANCE_FLAGS) == 0) {
712 process_one_v4_ace(&effective_acl_state, ace);
713 continue;
714 }
715 if (!(flags & NFS4_ACL_DIR))
716 goto out_dstate;
717 /*
718 * Note that when only one of FILE_INHERIT or DIRECTORY_INHERIT
719 * is set, we're effectively turning on the other. That's OK,
720 * according to rfc 3530.
721 */
722 process_one_v4_ace(&default_acl_state, ace);
723
724 if (!(ace->flag & NFS4_ACE_INHERIT_ONLY_ACE))
725 process_one_v4_ace(&effective_acl_state, ace);
726 }
727
728 /*
729 * At this point, the default ACL may have zeroed-out entries for owner,
730 * group and other. That usually results in a non-sensical resulting ACL
731 * that denies all access except to any ACE that was explicitly added.
732 *
733 * The setfacl command solves a similar problem with this logic:
734 *
735 * "If a Default ACL entry is created, and the Default ACL contains
736 * no owner, owning group, or others entry, a copy of the ACL
737 * owner, owning group, or others entry is added to the Default ACL."
738 *
739 * Copy any missing ACEs from the effective set, if any ACEs were
740 * explicitly set.
741 */
742 if (default_acl_state.valid) {
743 if (!(default_acl_state.valid & ACL_USER_OBJ))
744 default_acl_state.owner = effective_acl_state.owner;
745 if (!(default_acl_state.valid & ACL_GROUP_OBJ))
746 default_acl_state.group = effective_acl_state.group;
747 if (!(default_acl_state.valid & ACL_OTHER))
748 default_acl_state.other = effective_acl_state.other;
749 }
750
751 *pacl = posix_state_to_acl(&effective_acl_state, flags);
752 if (IS_ERR(*pacl)) {
753 ret = PTR_ERR(*pacl);
754 *pacl = NULL;
755 goto out_dstate;
756 }
757 *dpacl = posix_state_to_acl(&default_acl_state,
758 flags | NFS4_ACL_TYPE_DEFAULT);
759 if (IS_ERR(*dpacl)) {
760 ret = PTR_ERR(*dpacl);
761 *dpacl = NULL;
762 posix_acl_release(*pacl);
763 *pacl = NULL;
764 goto out_dstate;
765 }
766 sort_pacl(*pacl);
767 sort_pacl(*dpacl);
768 ret = 0;
769out_dstate:
770 free_state(&default_acl_state);
771out_estate:
772 free_state(&effective_acl_state);
773 return ret;
774}
775
776__be32 nfsd4_acl_to_attr(enum nfs_ftype4 type, struct nfs4_acl *acl,
777 struct nfsd_attrs *attr)
778{
779 int host_error;
780 unsigned int flags = 0;
781
782 if (!acl)
783 return nfs_ok;
784
785 if (type == NF4DIR)
786 flags = NFS4_ACL_DIR;
787
788 host_error = nfs4_acl_nfsv4_to_posix(acl, &attr->na_pacl,
789 &attr->na_dpacl, flags);
790 if (host_error == -EINVAL)
791 return nfserr_attrnotsupp;
792 else
793 return nfserrno(host_error);
794}
795
796static short
797ace2type(struct nfs4_ace *ace)
798{
799 switch (ace->whotype) {
800 case NFS4_ACL_WHO_NAMED:
801 return (ace->flag & NFS4_ACE_IDENTIFIER_GROUP ?
802 ACL_GROUP : ACL_USER);
803 case NFS4_ACL_WHO_OWNER:
804 return ACL_USER_OBJ;
805 case NFS4_ACL_WHO_GROUP:
806 return ACL_GROUP_OBJ;
807 case NFS4_ACL_WHO_EVERYONE:
808 return ACL_OTHER;
809 }
810 BUG();
811 return -1;
812}
813
814/*
815 * return the size of the struct nfs4_acl required to represent an acl
816 * with @entries entries.
817 */
818int nfs4_acl_bytes(int entries)
819{
820 return sizeof(struct nfs4_acl) + entries * sizeof(struct nfs4_ace);
821}
822
823static struct {
824 char *string;
825 int stringlen;
826 int type;
827} s2t_map[] = {
828 {
829 .string = "OWNER@",
830 .stringlen = sizeof("OWNER@") - 1,
831 .type = NFS4_ACL_WHO_OWNER,
832 },
833 {
834 .string = "GROUP@",
835 .stringlen = sizeof("GROUP@") - 1,
836 .type = NFS4_ACL_WHO_GROUP,
837 },
838 {
839 .string = "EVERYONE@",
840 .stringlen = sizeof("EVERYONE@") - 1,
841 .type = NFS4_ACL_WHO_EVERYONE,
842 },
843};
844
845int
846nfs4_acl_get_whotype(char *p, u32 len)
847{
848 int i;
849
850 for (i = 0; i < ARRAY_SIZE(s2t_map); i++) {
851 if (s2t_map[i].stringlen == len &&
852 0 == memcmp(s2t_map[i].string, p, len))
853 return s2t_map[i].type;
854 }
855 return NFS4_ACL_WHO_NAMED;
856}
857
858__be32 nfs4_acl_write_who(struct xdr_stream *xdr, int who)
859{
860 __be32 *p;
861 int i;
862
863 for (i = 0; i < ARRAY_SIZE(s2t_map); i++) {
864 if (s2t_map[i].type != who)
865 continue;
866 p = xdr_reserve_space(xdr, s2t_map[i].stringlen + 4);
867 if (!p)
868 return nfserr_resource;
869 p = xdr_encode_opaque(p, s2t_map[i].string,
870 s2t_map[i].stringlen);
871 return 0;
872 }
873 WARN_ON_ONCE(1);
874 return nfserr_serverfault;
875}
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 "nfsfh.h"
41#include "nfsd.h"
42#include "acl.h"
43#include "vfs.h"
44
45#define NFS4_ACL_TYPE_DEFAULT 0x01
46#define NFS4_ACL_DIR 0x02
47#define NFS4_ACL_OWNER 0x04
48
49/* mode bit translations: */
50#define NFS4_READ_MODE (NFS4_ACE_READ_DATA)
51#define NFS4_WRITE_MODE (NFS4_ACE_WRITE_DATA | NFS4_ACE_APPEND_DATA)
52#define NFS4_EXECUTE_MODE NFS4_ACE_EXECUTE
53#define NFS4_ANYONE_MODE (NFS4_ACE_READ_ATTRIBUTES | NFS4_ACE_READ_ACL | NFS4_ACE_SYNCHRONIZE)
54#define NFS4_OWNER_MODE (NFS4_ACE_WRITE_ATTRIBUTES | NFS4_ACE_WRITE_ACL)
55
56/* We don't support these bits; insist they be neither allowed nor denied */
57#define NFS4_MASK_UNSUPP (NFS4_ACE_DELETE | NFS4_ACE_WRITE_OWNER \
58 | NFS4_ACE_READ_NAMED_ATTRS | NFS4_ACE_WRITE_NAMED_ATTRS)
59
60/* flags used to simulate posix default ACLs */
61#define NFS4_INHERITANCE_FLAGS (NFS4_ACE_FILE_INHERIT_ACE \
62 | NFS4_ACE_DIRECTORY_INHERIT_ACE)
63
64#define NFS4_SUPPORTED_FLAGS (NFS4_INHERITANCE_FLAGS \
65 | NFS4_ACE_INHERIT_ONLY_ACE \
66 | NFS4_ACE_IDENTIFIER_GROUP)
67
68#define MASK_EQUAL(mask1, mask2) \
69 ( ((mask1) & NFS4_ACE_MASK_ALL) == ((mask2) & NFS4_ACE_MASK_ALL) )
70
71static u32
72mask_from_posix(unsigned short perm, unsigned int flags)
73{
74 int mask = NFS4_ANYONE_MODE;
75
76 if (flags & NFS4_ACL_OWNER)
77 mask |= NFS4_OWNER_MODE;
78 if (perm & ACL_READ)
79 mask |= NFS4_READ_MODE;
80 if (perm & ACL_WRITE)
81 mask |= NFS4_WRITE_MODE;
82 if ((perm & ACL_WRITE) && (flags & NFS4_ACL_DIR))
83 mask |= NFS4_ACE_DELETE_CHILD;
84 if (perm & ACL_EXECUTE)
85 mask |= NFS4_EXECUTE_MODE;
86 return mask;
87}
88
89static u32
90deny_mask_from_posix(unsigned short perm, u32 flags)
91{
92 u32 mask = 0;
93
94 if (perm & ACL_READ)
95 mask |= NFS4_READ_MODE;
96 if (perm & ACL_WRITE)
97 mask |= NFS4_WRITE_MODE;
98 if ((perm & ACL_WRITE) && (flags & NFS4_ACL_DIR))
99 mask |= NFS4_ACE_DELETE_CHILD;
100 if (perm & ACL_EXECUTE)
101 mask |= NFS4_EXECUTE_MODE;
102 return mask;
103}
104
105/* XXX: modify functions to return NFS errors; they're only ever
106 * used by nfs code, after all.... */
107
108/* We only map from NFSv4 to POSIX ACLs when setting ACLs, when we err on the
109 * side of being more restrictive, so the mode bit mapping below is
110 * pessimistic. An optimistic version would be needed to handle DENY's,
111 * but we espect to coalesce all ALLOWs and DENYs before mapping to mode
112 * bits. */
113
114static void
115low_mode_from_nfs4(u32 perm, unsigned short *mode, unsigned int flags)
116{
117 u32 write_mode = NFS4_WRITE_MODE;
118
119 if (flags & NFS4_ACL_DIR)
120 write_mode |= NFS4_ACE_DELETE_CHILD;
121 *mode = 0;
122 if ((perm & NFS4_READ_MODE) == NFS4_READ_MODE)
123 *mode |= ACL_READ;
124 if ((perm & write_mode) == write_mode)
125 *mode |= ACL_WRITE;
126 if ((perm & NFS4_EXECUTE_MODE) == NFS4_EXECUTE_MODE)
127 *mode |= ACL_EXECUTE;
128}
129
130struct ace_container {
131 struct nfs4_ace *ace;
132 struct list_head ace_l;
133};
134
135static short ace2type(struct nfs4_ace *);
136static void _posix_to_nfsv4_one(struct posix_acl *, struct nfs4_acl *,
137 unsigned int);
138
139int
140nfsd4_get_nfs4_acl(struct svc_rqst *rqstp, struct dentry *dentry,
141 struct nfs4_acl **acl)
142{
143 struct inode *inode = dentry->d_inode;
144 int error = 0;
145 struct posix_acl *pacl = NULL, *dpacl = NULL;
146 unsigned int flags = 0;
147 int size = 0;
148
149 pacl = get_acl(inode, ACL_TYPE_ACCESS);
150 if (!pacl) {
151 pacl = posix_acl_from_mode(inode->i_mode, GFP_KERNEL);
152 if (IS_ERR(pacl))
153 return PTR_ERR(pacl);
154 }
155 /* allocate for worst case: one (deny, allow) pair each: */
156 size += 2 * pacl->a_count;
157
158 if (S_ISDIR(inode->i_mode)) {
159 flags = NFS4_ACL_DIR;
160 dpacl = get_acl(inode, ACL_TYPE_DEFAULT);
161 if (dpacl)
162 size += 2 * dpacl->a_count;
163 }
164
165 *acl = nfs4_acl_new(size);
166 if (*acl == NULL) {
167 error = -ENOMEM;
168 goto out;
169 }
170
171 _posix_to_nfsv4_one(pacl, *acl, flags & ~NFS4_ACL_TYPE_DEFAULT);
172
173 if (dpacl)
174 _posix_to_nfsv4_one(dpacl, *acl, flags | NFS4_ACL_TYPE_DEFAULT);
175
176 out:
177 posix_acl_release(pacl);
178 posix_acl_release(dpacl);
179 return error;
180}
181
182struct posix_acl_summary {
183 unsigned short owner;
184 unsigned short users;
185 unsigned short group;
186 unsigned short groups;
187 unsigned short other;
188 unsigned short mask;
189};
190
191static void
192summarize_posix_acl(struct posix_acl *acl, struct posix_acl_summary *pas)
193{
194 struct posix_acl_entry *pa, *pe;
195
196 /*
197 * Only pas.users and pas.groups need initialization; previous
198 * posix_acl_valid() calls ensure that the other fields will be
199 * initialized in the following loop. But, just to placate gcc:
200 */
201 memset(pas, 0, sizeof(*pas));
202 pas->mask = 07;
203
204 pe = acl->a_entries + acl->a_count;
205
206 FOREACH_ACL_ENTRY(pa, acl, pe) {
207 switch (pa->e_tag) {
208 case ACL_USER_OBJ:
209 pas->owner = pa->e_perm;
210 break;
211 case ACL_GROUP_OBJ:
212 pas->group = pa->e_perm;
213 break;
214 case ACL_USER:
215 pas->users |= pa->e_perm;
216 break;
217 case ACL_GROUP:
218 pas->groups |= pa->e_perm;
219 break;
220 case ACL_OTHER:
221 pas->other = pa->e_perm;
222 break;
223 case ACL_MASK:
224 pas->mask = pa->e_perm;
225 break;
226 }
227 }
228 /* We'll only care about effective permissions: */
229 pas->users &= pas->mask;
230 pas->group &= pas->mask;
231 pas->groups &= pas->mask;
232}
233
234/* We assume the acl has been verified with posix_acl_valid. */
235static void
236_posix_to_nfsv4_one(struct posix_acl *pacl, struct nfs4_acl *acl,
237 unsigned int flags)
238{
239 struct posix_acl_entry *pa, *group_owner_entry;
240 struct nfs4_ace *ace;
241 struct posix_acl_summary pas;
242 unsigned short deny;
243 int eflag = ((flags & NFS4_ACL_TYPE_DEFAULT) ?
244 NFS4_INHERITANCE_FLAGS | NFS4_ACE_INHERIT_ONLY_ACE : 0);
245
246 BUG_ON(pacl->a_count < 3);
247 summarize_posix_acl(pacl, &pas);
248
249 pa = pacl->a_entries;
250 ace = acl->aces + acl->naces;
251
252 /* We could deny everything not granted by the owner: */
253 deny = ~pas.owner;
254 /*
255 * but it is equivalent (and simpler) to deny only what is not
256 * granted by later entries:
257 */
258 deny &= pas.users | pas.group | pas.groups | pas.other;
259 if (deny) {
260 ace->type = NFS4_ACE_ACCESS_DENIED_ACE_TYPE;
261 ace->flag = eflag;
262 ace->access_mask = deny_mask_from_posix(deny, flags);
263 ace->whotype = NFS4_ACL_WHO_OWNER;
264 ace++;
265 acl->naces++;
266 }
267
268 ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
269 ace->flag = eflag;
270 ace->access_mask = mask_from_posix(pa->e_perm, flags | NFS4_ACL_OWNER);
271 ace->whotype = NFS4_ACL_WHO_OWNER;
272 ace++;
273 acl->naces++;
274 pa++;
275
276 while (pa->e_tag == ACL_USER) {
277 deny = ~(pa->e_perm & pas.mask);
278 deny &= pas.groups | pas.group | pas.other;
279 if (deny) {
280 ace->type = NFS4_ACE_ACCESS_DENIED_ACE_TYPE;
281 ace->flag = eflag;
282 ace->access_mask = deny_mask_from_posix(deny, flags);
283 ace->whotype = NFS4_ACL_WHO_NAMED;
284 ace->who_uid = pa->e_uid;
285 ace++;
286 acl->naces++;
287 }
288 ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
289 ace->flag = eflag;
290 ace->access_mask = mask_from_posix(pa->e_perm & pas.mask,
291 flags);
292 ace->whotype = NFS4_ACL_WHO_NAMED;
293 ace->who_uid = pa->e_uid;
294 ace++;
295 acl->naces++;
296 pa++;
297 }
298
299 /* In the case of groups, we apply allow ACEs first, then deny ACEs,
300 * since a user can be in more than one group. */
301
302 /* allow ACEs */
303
304 group_owner_entry = pa;
305
306 ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
307 ace->flag = eflag;
308 ace->access_mask = mask_from_posix(pas.group, flags);
309 ace->whotype = NFS4_ACL_WHO_GROUP;
310 ace++;
311 acl->naces++;
312 pa++;
313
314 while (pa->e_tag == ACL_GROUP) {
315 ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
316 ace->flag = eflag | NFS4_ACE_IDENTIFIER_GROUP;
317 ace->access_mask = mask_from_posix(pa->e_perm & pas.mask,
318 flags);
319 ace->whotype = NFS4_ACL_WHO_NAMED;
320 ace->who_gid = pa->e_gid;
321 ace++;
322 acl->naces++;
323 pa++;
324 }
325
326 /* deny ACEs */
327
328 pa = group_owner_entry;
329
330 deny = ~pas.group & pas.other;
331 if (deny) {
332 ace->type = NFS4_ACE_ACCESS_DENIED_ACE_TYPE;
333 ace->flag = eflag;
334 ace->access_mask = deny_mask_from_posix(deny, flags);
335 ace->whotype = NFS4_ACL_WHO_GROUP;
336 ace++;
337 acl->naces++;
338 }
339 pa++;
340
341 while (pa->e_tag == ACL_GROUP) {
342 deny = ~(pa->e_perm & pas.mask);
343 deny &= pas.other;
344 if (deny) {
345 ace->type = NFS4_ACE_ACCESS_DENIED_ACE_TYPE;
346 ace->flag = eflag | NFS4_ACE_IDENTIFIER_GROUP;
347 ace->access_mask = deny_mask_from_posix(deny, flags);
348 ace->whotype = NFS4_ACL_WHO_NAMED;
349 ace->who_gid = pa->e_gid;
350 ace++;
351 acl->naces++;
352 }
353 pa++;
354 }
355
356 if (pa->e_tag == ACL_MASK)
357 pa++;
358 ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
359 ace->flag = eflag;
360 ace->access_mask = mask_from_posix(pa->e_perm, flags);
361 ace->whotype = NFS4_ACL_WHO_EVERYONE;
362 acl->naces++;
363}
364
365static bool
366pace_gt(struct posix_acl_entry *pace1, struct posix_acl_entry *pace2)
367{
368 if (pace1->e_tag != pace2->e_tag)
369 return pace1->e_tag > pace2->e_tag;
370 if (pace1->e_tag == ACL_USER)
371 return uid_gt(pace1->e_uid, pace2->e_uid);
372 if (pace1->e_tag == ACL_GROUP)
373 return gid_gt(pace1->e_gid, pace2->e_gid);
374 return false;
375}
376
377static void
378sort_pacl_range(struct posix_acl *pacl, int start, int end) {
379 int sorted = 0, i;
380 struct posix_acl_entry tmp;
381
382 /* We just do a bubble sort; easy to do in place, and we're not
383 * expecting acl's to be long enough to justify anything more. */
384 while (!sorted) {
385 sorted = 1;
386 for (i = start; i < end; i++) {
387 if (pace_gt(&pacl->a_entries[i],
388 &pacl->a_entries[i+1])) {
389 sorted = 0;
390 tmp = pacl->a_entries[i];
391 pacl->a_entries[i] = pacl->a_entries[i+1];
392 pacl->a_entries[i+1] = tmp;
393 }
394 }
395 }
396}
397
398static void
399sort_pacl(struct posix_acl *pacl)
400{
401 /* posix_acl_valid requires that users and groups be in order
402 * by uid/gid. */
403 int i, j;
404
405 /* no users or groups */
406 if (!pacl || pacl->a_count <= 4)
407 return;
408
409 i = 1;
410 while (pacl->a_entries[i].e_tag == ACL_USER)
411 i++;
412 sort_pacl_range(pacl, 1, i-1);
413
414 BUG_ON(pacl->a_entries[i].e_tag != ACL_GROUP_OBJ);
415 j = ++i;
416 while (pacl->a_entries[j].e_tag == ACL_GROUP)
417 j++;
418 sort_pacl_range(pacl, i, j-1);
419 return;
420}
421
422/*
423 * While processing the NFSv4 ACE, this maintains bitmasks representing
424 * which permission bits have been allowed and which denied to a given
425 * entity: */
426struct posix_ace_state {
427 u32 allow;
428 u32 deny;
429};
430
431struct posix_user_ace_state {
432 union {
433 kuid_t uid;
434 kgid_t gid;
435 };
436 struct posix_ace_state perms;
437};
438
439struct posix_ace_state_array {
440 int n;
441 struct posix_user_ace_state aces[];
442};
443
444/*
445 * While processing the NFSv4 ACE, this maintains the partial permissions
446 * calculated so far: */
447
448struct posix_acl_state {
449 int empty;
450 struct posix_ace_state owner;
451 struct posix_ace_state group;
452 struct posix_ace_state other;
453 struct posix_ace_state everyone;
454 struct posix_ace_state mask; /* Deny unused in this case */
455 struct posix_ace_state_array *users;
456 struct posix_ace_state_array *groups;
457};
458
459static int
460init_state(struct posix_acl_state *state, int cnt)
461{
462 int alloc;
463
464 memset(state, 0, sizeof(struct posix_acl_state));
465 state->empty = 1;
466 /*
467 * In the worst case, each individual acl could be for a distinct
468 * named user or group, but we don't no which, so we allocate
469 * enough space for either:
470 */
471 alloc = sizeof(struct posix_ace_state_array)
472 + cnt*sizeof(struct posix_user_ace_state);
473 state->users = kzalloc(alloc, GFP_KERNEL);
474 if (!state->users)
475 return -ENOMEM;
476 state->groups = kzalloc(alloc, GFP_KERNEL);
477 if (!state->groups) {
478 kfree(state->users);
479 return -ENOMEM;
480 }
481 return 0;
482}
483
484static void
485free_state(struct posix_acl_state *state) {
486 kfree(state->users);
487 kfree(state->groups);
488}
489
490static inline void add_to_mask(struct posix_acl_state *state, struct posix_ace_state *astate)
491{
492 state->mask.allow |= astate->allow;
493}
494
495/*
496 * Certain bits (SYNCHRONIZE, DELETE, WRITE_OWNER, READ/WRITE_NAMED_ATTRS,
497 * READ_ATTRIBUTES, READ_ACL) are currently unenforceable and don't translate
498 * to traditional read/write/execute permissions.
499 *
500 * It's problematic to reject acls that use certain mode bits, because it
501 * places the burden on users to learn the rules about which bits one
502 * particular server sets, without giving the user a lot of help--we return an
503 * error that could mean any number of different things. To make matters
504 * worse, the problematic bits might be introduced by some application that's
505 * automatically mapping from some other acl model.
506 *
507 * So wherever possible we accept anything, possibly erring on the side of
508 * denying more permissions than necessary.
509 *
510 * However we do reject *explicit* DENY's of a few bits representing
511 * permissions we could never deny:
512 */
513
514static inline int check_deny(u32 mask, int isowner)
515{
516 if (mask & (NFS4_ACE_READ_ATTRIBUTES | NFS4_ACE_READ_ACL))
517 return -EINVAL;
518 if (!isowner)
519 return 0;
520 if (mask & (NFS4_ACE_WRITE_ATTRIBUTES | NFS4_ACE_WRITE_ACL))
521 return -EINVAL;
522 return 0;
523}
524
525static struct posix_acl *
526posix_state_to_acl(struct posix_acl_state *state, unsigned int flags)
527{
528 struct posix_acl_entry *pace;
529 struct posix_acl *pacl;
530 int nace;
531 int i, error = 0;
532
533 /*
534 * ACLs with no ACEs are treated differently in the inheritable
535 * and effective cases: when there are no inheritable ACEs,
536 * calls ->set_acl with a NULL ACL structure.
537 */
538 if (state->empty && (flags & NFS4_ACL_TYPE_DEFAULT))
539 return NULL;
540
541 /*
542 * When there are no effective ACEs, the following will end
543 * up setting a 3-element effective posix ACL with all
544 * permissions zero.
545 */
546 if (!state->users->n && !state->groups->n)
547 nace = 3;
548 else /* Note we also include a MASK ACE in this case: */
549 nace = 4 + state->users->n + state->groups->n;
550 pacl = posix_acl_alloc(nace, GFP_KERNEL);
551 if (!pacl)
552 return ERR_PTR(-ENOMEM);
553
554 pace = pacl->a_entries;
555 pace->e_tag = ACL_USER_OBJ;
556 error = check_deny(state->owner.deny, 1);
557 if (error)
558 goto out_err;
559 low_mode_from_nfs4(state->owner.allow, &pace->e_perm, flags);
560
561 for (i=0; i < state->users->n; i++) {
562 pace++;
563 pace->e_tag = ACL_USER;
564 error = check_deny(state->users->aces[i].perms.deny, 0);
565 if (error)
566 goto out_err;
567 low_mode_from_nfs4(state->users->aces[i].perms.allow,
568 &pace->e_perm, flags);
569 pace->e_uid = state->users->aces[i].uid;
570 add_to_mask(state, &state->users->aces[i].perms);
571 }
572
573 pace++;
574 pace->e_tag = ACL_GROUP_OBJ;
575 error = check_deny(state->group.deny, 0);
576 if (error)
577 goto out_err;
578 low_mode_from_nfs4(state->group.allow, &pace->e_perm, flags);
579 add_to_mask(state, &state->group);
580
581 for (i=0; i < state->groups->n; i++) {
582 pace++;
583 pace->e_tag = ACL_GROUP;
584 error = check_deny(state->groups->aces[i].perms.deny, 0);
585 if (error)
586 goto out_err;
587 low_mode_from_nfs4(state->groups->aces[i].perms.allow,
588 &pace->e_perm, flags);
589 pace->e_gid = state->groups->aces[i].gid;
590 add_to_mask(state, &state->groups->aces[i].perms);
591 }
592
593 if (state->users->n || state->groups->n) {
594 pace++;
595 pace->e_tag = ACL_MASK;
596 low_mode_from_nfs4(state->mask.allow, &pace->e_perm, flags);
597 }
598
599 pace++;
600 pace->e_tag = ACL_OTHER;
601 error = check_deny(state->other.deny, 0);
602 if (error)
603 goto out_err;
604 low_mode_from_nfs4(state->other.allow, &pace->e_perm, flags);
605
606 return pacl;
607out_err:
608 posix_acl_release(pacl);
609 return ERR_PTR(error);
610}
611
612static inline void allow_bits(struct posix_ace_state *astate, u32 mask)
613{
614 /* Allow all bits in the mask not already denied: */
615 astate->allow |= mask & ~astate->deny;
616}
617
618static inline void deny_bits(struct posix_ace_state *astate, u32 mask)
619{
620 /* Deny all bits in the mask not already allowed: */
621 astate->deny |= mask & ~astate->allow;
622}
623
624static int find_uid(struct posix_acl_state *state, kuid_t uid)
625{
626 struct posix_ace_state_array *a = state->users;
627 int i;
628
629 for (i = 0; i < a->n; i++)
630 if (uid_eq(a->aces[i].uid, uid))
631 return i;
632 /* Not found: */
633 a->n++;
634 a->aces[i].uid = uid;
635 a->aces[i].perms.allow = state->everyone.allow;
636 a->aces[i].perms.deny = state->everyone.deny;
637
638 return i;
639}
640
641static int find_gid(struct posix_acl_state *state, kgid_t gid)
642{
643 struct posix_ace_state_array *a = state->groups;
644 int i;
645
646 for (i = 0; i < a->n; i++)
647 if (gid_eq(a->aces[i].gid, gid))
648 return i;
649 /* Not found: */
650 a->n++;
651 a->aces[i].gid = gid;
652 a->aces[i].perms.allow = state->everyone.allow;
653 a->aces[i].perms.deny = state->everyone.deny;
654
655 return i;
656}
657
658static void deny_bits_array(struct posix_ace_state_array *a, u32 mask)
659{
660 int i;
661
662 for (i=0; i < a->n; i++)
663 deny_bits(&a->aces[i].perms, mask);
664}
665
666static void allow_bits_array(struct posix_ace_state_array *a, u32 mask)
667{
668 int i;
669
670 for (i=0; i < a->n; i++)
671 allow_bits(&a->aces[i].perms, mask);
672}
673
674static void process_one_v4_ace(struct posix_acl_state *state,
675 struct nfs4_ace *ace)
676{
677 u32 mask = ace->access_mask;
678 int i;
679
680 state->empty = 0;
681
682 switch (ace2type(ace)) {
683 case ACL_USER_OBJ:
684 if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
685 allow_bits(&state->owner, mask);
686 } else {
687 deny_bits(&state->owner, mask);
688 }
689 break;
690 case ACL_USER:
691 i = find_uid(state, ace->who_uid);
692 if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
693 allow_bits(&state->users->aces[i].perms, mask);
694 } else {
695 deny_bits(&state->users->aces[i].perms, mask);
696 mask = state->users->aces[i].perms.deny;
697 deny_bits(&state->owner, mask);
698 }
699 break;
700 case ACL_GROUP_OBJ:
701 if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
702 allow_bits(&state->group, mask);
703 } else {
704 deny_bits(&state->group, mask);
705 mask = state->group.deny;
706 deny_bits(&state->owner, mask);
707 deny_bits(&state->everyone, mask);
708 deny_bits_array(state->users, mask);
709 deny_bits_array(state->groups, mask);
710 }
711 break;
712 case ACL_GROUP:
713 i = find_gid(state, ace->who_gid);
714 if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
715 allow_bits(&state->groups->aces[i].perms, mask);
716 } else {
717 deny_bits(&state->groups->aces[i].perms, mask);
718 mask = state->groups->aces[i].perms.deny;
719 deny_bits(&state->owner, mask);
720 deny_bits(&state->group, mask);
721 deny_bits(&state->everyone, mask);
722 deny_bits_array(state->users, mask);
723 deny_bits_array(state->groups, mask);
724 }
725 break;
726 case ACL_OTHER:
727 if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
728 allow_bits(&state->owner, mask);
729 allow_bits(&state->group, mask);
730 allow_bits(&state->other, mask);
731 allow_bits(&state->everyone, mask);
732 allow_bits_array(state->users, mask);
733 allow_bits_array(state->groups, mask);
734 } else {
735 deny_bits(&state->owner, mask);
736 deny_bits(&state->group, mask);
737 deny_bits(&state->other, mask);
738 deny_bits(&state->everyone, mask);
739 deny_bits_array(state->users, mask);
740 deny_bits_array(state->groups, mask);
741 }
742 }
743}
744
745static int nfs4_acl_nfsv4_to_posix(struct nfs4_acl *acl,
746 struct posix_acl **pacl, struct posix_acl **dpacl,
747 unsigned int flags)
748{
749 struct posix_acl_state effective_acl_state, default_acl_state;
750 struct nfs4_ace *ace;
751 int ret;
752
753 ret = init_state(&effective_acl_state, acl->naces);
754 if (ret)
755 return ret;
756 ret = init_state(&default_acl_state, acl->naces);
757 if (ret)
758 goto out_estate;
759 ret = -EINVAL;
760 for (ace = acl->aces; ace < acl->aces + acl->naces; ace++) {
761 if (ace->type != NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE &&
762 ace->type != NFS4_ACE_ACCESS_DENIED_ACE_TYPE)
763 goto out_dstate;
764 if (ace->flag & ~NFS4_SUPPORTED_FLAGS)
765 goto out_dstate;
766 if ((ace->flag & NFS4_INHERITANCE_FLAGS) == 0) {
767 process_one_v4_ace(&effective_acl_state, ace);
768 continue;
769 }
770 if (!(flags & NFS4_ACL_DIR))
771 goto out_dstate;
772 /*
773 * Note that when only one of FILE_INHERIT or DIRECTORY_INHERIT
774 * is set, we're effectively turning on the other. That's OK,
775 * according to rfc 3530.
776 */
777 process_one_v4_ace(&default_acl_state, ace);
778
779 if (!(ace->flag & NFS4_ACE_INHERIT_ONLY_ACE))
780 process_one_v4_ace(&effective_acl_state, ace);
781 }
782 *pacl = posix_state_to_acl(&effective_acl_state, flags);
783 if (IS_ERR(*pacl)) {
784 ret = PTR_ERR(*pacl);
785 *pacl = NULL;
786 goto out_dstate;
787 }
788 *dpacl = posix_state_to_acl(&default_acl_state,
789 flags | NFS4_ACL_TYPE_DEFAULT);
790 if (IS_ERR(*dpacl)) {
791 ret = PTR_ERR(*dpacl);
792 *dpacl = NULL;
793 posix_acl_release(*pacl);
794 *pacl = NULL;
795 goto out_dstate;
796 }
797 sort_pacl(*pacl);
798 sort_pacl(*dpacl);
799 ret = 0;
800out_dstate:
801 free_state(&default_acl_state);
802out_estate:
803 free_state(&effective_acl_state);
804 return ret;
805}
806
807__be32
808nfsd4_set_nfs4_acl(struct svc_rqst *rqstp, struct svc_fh *fhp,
809 struct nfs4_acl *acl)
810{
811 __be32 error;
812 int host_error;
813 struct dentry *dentry;
814 struct inode *inode;
815 struct posix_acl *pacl = NULL, *dpacl = NULL;
816 unsigned int flags = 0;
817
818 /* Get inode */
819 error = fh_verify(rqstp, fhp, 0, NFSD_MAY_SATTR);
820 if (error)
821 return error;
822
823 dentry = fhp->fh_dentry;
824 inode = dentry->d_inode;
825
826 if (!inode->i_op->set_acl || !IS_POSIXACL(inode))
827 return nfserr_attrnotsupp;
828
829 if (S_ISDIR(inode->i_mode))
830 flags = NFS4_ACL_DIR;
831
832 host_error = nfs4_acl_nfsv4_to_posix(acl, &pacl, &dpacl, flags);
833 if (host_error == -EINVAL)
834 return nfserr_attrnotsupp;
835 if (host_error < 0)
836 goto out_nfserr;
837
838 host_error = inode->i_op->set_acl(inode, pacl, ACL_TYPE_ACCESS);
839 if (host_error < 0)
840 goto out_release;
841
842 if (S_ISDIR(inode->i_mode)) {
843 host_error = inode->i_op->set_acl(inode, dpacl,
844 ACL_TYPE_DEFAULT);
845 }
846
847out_release:
848 posix_acl_release(pacl);
849 posix_acl_release(dpacl);
850out_nfserr:
851 if (host_error == -EOPNOTSUPP)
852 return nfserr_attrnotsupp;
853 else
854 return nfserrno(host_error);
855}
856
857
858static short
859ace2type(struct nfs4_ace *ace)
860{
861 switch (ace->whotype) {
862 case NFS4_ACL_WHO_NAMED:
863 return (ace->flag & NFS4_ACE_IDENTIFIER_GROUP ?
864 ACL_GROUP : ACL_USER);
865 case NFS4_ACL_WHO_OWNER:
866 return ACL_USER_OBJ;
867 case NFS4_ACL_WHO_GROUP:
868 return ACL_GROUP_OBJ;
869 case NFS4_ACL_WHO_EVERYONE:
870 return ACL_OTHER;
871 }
872 BUG();
873 return -1;
874}
875
876struct nfs4_acl *
877nfs4_acl_new(int n)
878{
879 struct nfs4_acl *acl;
880
881 acl = kmalloc(sizeof(*acl) + n*sizeof(struct nfs4_ace), GFP_KERNEL);
882 if (acl == NULL)
883 return NULL;
884 acl->naces = 0;
885 return acl;
886}
887
888static struct {
889 char *string;
890 int stringlen;
891 int type;
892} s2t_map[] = {
893 {
894 .string = "OWNER@",
895 .stringlen = sizeof("OWNER@") - 1,
896 .type = NFS4_ACL_WHO_OWNER,
897 },
898 {
899 .string = "GROUP@",
900 .stringlen = sizeof("GROUP@") - 1,
901 .type = NFS4_ACL_WHO_GROUP,
902 },
903 {
904 .string = "EVERYONE@",
905 .stringlen = sizeof("EVERYONE@") - 1,
906 .type = NFS4_ACL_WHO_EVERYONE,
907 },
908};
909
910int
911nfs4_acl_get_whotype(char *p, u32 len)
912{
913 int i;
914
915 for (i = 0; i < ARRAY_SIZE(s2t_map); i++) {
916 if (s2t_map[i].stringlen == len &&
917 0 == memcmp(s2t_map[i].string, p, len))
918 return s2t_map[i].type;
919 }
920 return NFS4_ACL_WHO_NAMED;
921}
922
923__be32 nfs4_acl_write_who(int who, __be32 **p, int *len)
924{
925 int i;
926 int bytes;
927
928 for (i = 0; i < ARRAY_SIZE(s2t_map); i++) {
929 if (s2t_map[i].type != who)
930 continue;
931 bytes = 4 + (XDR_QUADLEN(s2t_map[i].stringlen) << 2);
932 if (bytes > *len)
933 return nfserr_resource;
934 *p = xdr_encode_opaque(*p, s2t_map[i].string,
935 s2t_map[i].stringlen);
936 *len -= bytes;
937 return 0;
938 }
939 WARN_ON_ONCE(1);
940 return -1;
941}