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1/*
2 * Common NFSv4 ACL handling code.
3 *
4 * Copyright (c) 2002, 2003 The Regents of the University of Michigan.
5 * All rights reserved.
6 *
7 * Marius Aamodt Eriksen <marius@umich.edu>
8 * Jeff Sedlak <jsedlak@umich.edu>
9 * J. Bruce Fields <bfields@umich.edu>
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 *
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. Neither the name of the University nor the names of its
21 * contributors may be used to endorse or promote products derived
22 * from this software without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
25 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
26 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
27 * DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
29 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
30 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
31 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
32 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
33 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
34 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
35 */
36
37#include <linux/slab.h>
38#include <linux/nfs_fs.h>
39#include <linux/export.h>
40#include "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}
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);