4 * Common NFSv4 ACL handling code.
6 * Copyright (c) 2002, 2003 The Regents of the University of Michigan.
9 * Marius Aamodt Eriksen <marius@umich.edu>
10 * Jeff Sedlak <jsedlak@umich.edu>
11 * J. Bruce Fields <bfields@umich.edu>
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
17 * 1. Redistributions of source code must retain the above copyright
18 * notice, this list of conditions and the following disclaimer.
19 * 2. Redistributions in binary form must reproduce the above copyright
20 * notice, this list of conditions and the following disclaimer in the
21 * documentation and/or other materials provided with the distribution.
22 * 3. Neither the name of the University nor the names of its
23 * contributors may be used to endorse or promote products derived
24 * from this software without specific prior written permission.
26 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
27 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
28 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
29 * DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
33 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
34 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
35 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
36 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
39 #include <linux/string.h>
40 #include <linux/slab.h>
41 #include <linux/list.h>
42 #include <linux/types.h>
44 #include <linux/module.h>
45 #include <linux/nfs_fs.h>
46 #include <linux/posix_acl.h>
47 #include <linux/nfs4.h>
48 #include <linux/nfs4_acl.h>
51 /* mode bit translations: */
52 #define NFS4_READ_MODE (NFS4_ACE_READ_DATA)
53 #define NFS4_WRITE_MODE (NFS4_ACE_WRITE_DATA | NFS4_ACE_APPEND_DATA)
54 #define NFS4_EXECUTE_MODE NFS4_ACE_EXECUTE
55 #define NFS4_ANYONE_MODE (NFS4_ACE_READ_ATTRIBUTES | NFS4_ACE_READ_ACL | NFS4_ACE_SYNCHRONIZE)
56 #define NFS4_OWNER_MODE (NFS4_ACE_WRITE_ATTRIBUTES | NFS4_ACE_WRITE_ACL)
58 /* We don't support these bits; insist they be neither allowed nor denied */
59 #define NFS4_MASK_UNSUPP (NFS4_ACE_DELETE | NFS4_ACE_WRITE_OWNER \
60 | NFS4_ACE_READ_NAMED_ATTRS | NFS4_ACE_WRITE_NAMED_ATTRS)
62 /* flags used to simulate posix default ACLs */
63 #define NFS4_INHERITANCE_FLAGS (NFS4_ACE_FILE_INHERIT_ACE \
64 | NFS4_ACE_DIRECTORY_INHERIT_ACE)
66 #define NFS4_SUPPORTED_FLAGS (NFS4_INHERITANCE_FLAGS \
67 | NFS4_ACE_INHERIT_ONLY_ACE \
68 | NFS4_ACE_IDENTIFIER_GROUP)
70 #define MASK_EQUAL(mask1, mask2) \
71 ( ((mask1) & NFS4_ACE_MASK_ALL) == ((mask2) & NFS4_ACE_MASK_ALL) )
74 mask_from_posix(unsigned short perm, unsigned int flags)
76 int mask = NFS4_ANYONE_MODE;
78 if (flags & NFS4_ACL_OWNER)
79 mask |= NFS4_OWNER_MODE;
81 mask |= NFS4_READ_MODE;
83 mask |= NFS4_WRITE_MODE;
84 if ((perm & ACL_WRITE) && (flags & NFS4_ACL_DIR))
85 mask |= NFS4_ACE_DELETE_CHILD;
86 if (perm & ACL_EXECUTE)
87 mask |= NFS4_EXECUTE_MODE;
92 deny_mask(u32 allow_mask, unsigned int flags)
94 u32 ret = ~allow_mask & ~NFS4_MASK_UNSUPP;
95 if (!(flags & NFS4_ACL_DIR))
96 ret &= ~NFS4_ACE_DELETE_CHILD;
100 /* XXX: modify functions to return NFS errors; they're only ever
101 * used by nfs code, after all.... */
103 /* We only map from NFSv4 to POSIX ACLs when setting ACLs, when we err on the
104 * side of being more restrictive, so the mode bit mapping below is
105 * pessimistic. An optimistic version would be needed to handle DENY's,
106 * but we espect to coalesce all ALLOWs and DENYs before mapping to mode
110 low_mode_from_nfs4(u32 perm, unsigned short *mode, unsigned int flags)
112 u32 write_mode = NFS4_WRITE_MODE;
114 if (flags & NFS4_ACL_DIR)
115 write_mode |= NFS4_ACE_DELETE_CHILD;
117 if ((perm & NFS4_READ_MODE) == NFS4_READ_MODE)
119 if ((perm & write_mode) == write_mode)
121 if ((perm & NFS4_EXECUTE_MODE) == NFS4_EXECUTE_MODE)
122 *mode |= ACL_EXECUTE;
125 struct ace_container {
126 struct nfs4_ace *ace;
127 struct list_head ace_l;
130 static short ace2type(struct nfs4_ace *);
131 static void _posix_to_nfsv4_one(struct posix_acl *, struct nfs4_acl *,
133 void nfs4_acl_add_ace(struct nfs4_acl *, u32, u32, u32, int, uid_t);
136 nfs4_acl_posix_to_nfsv4(struct posix_acl *pacl, struct posix_acl *dpacl,
139 struct nfs4_acl *acl;
143 if (posix_acl_valid(pacl) < 0)
144 return ERR_PTR(-EINVAL);
145 size += 2*pacl->a_count;
148 if (posix_acl_valid(dpacl) < 0)
149 return ERR_PTR(-EINVAL);
150 size += 2*dpacl->a_count;
153 /* Allocate for worst case: one (deny, allow) pair each: */
154 acl = nfs4_acl_new(size);
156 return ERR_PTR(-ENOMEM);
159 _posix_to_nfsv4_one(pacl, acl, flags & ~NFS4_ACL_TYPE_DEFAULT);
162 _posix_to_nfsv4_one(dpacl, acl, flags | NFS4_ACL_TYPE_DEFAULT);
168 nfs4_acl_add_pair(struct nfs4_acl *acl, int eflag, u32 mask, int whotype,
169 uid_t owner, unsigned int flags)
171 nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE,
172 eflag, mask, whotype, owner);
173 nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_DENIED_ACE_TYPE,
174 eflag, deny_mask(mask, flags), whotype, owner);
177 /* We assume the acl has been verified with posix_acl_valid. */
179 _posix_to_nfsv4_one(struct posix_acl *pacl, struct nfs4_acl *acl,
182 struct posix_acl_entry *pa, *pe, *group_owner_entry;
184 unsigned short mask_mask;
185 int eflag = ((flags & NFS4_ACL_TYPE_DEFAULT) ?
186 NFS4_INHERITANCE_FLAGS : 0);
188 BUG_ON(pacl->a_count < 3);
189 pe = pacl->a_entries + pacl->a_count;
190 pa = pe - 2; /* if mask entry exists, it's second from the last. */
191 if (pa->e_tag == ACL_MASK)
192 mask_mask = pa->e_perm;
196 pa = pacl->a_entries;
197 BUG_ON(pa->e_tag != ACL_USER_OBJ);
198 mask = mask_from_posix(pa->e_perm, flags | NFS4_ACL_OWNER);
199 nfs4_acl_add_pair(acl, eflag, mask, NFS4_ACL_WHO_OWNER, 0, flags);
202 while (pa->e_tag == ACL_USER) {
203 mask = mask_from_posix(pa->e_perm & mask_mask, flags);
204 nfs4_acl_add_pair(acl, eflag, mask,
205 NFS4_ACL_WHO_NAMED, pa->e_id, flags);
209 /* In the case of groups, we apply allow ACEs first, then deny ACEs,
210 * since a user can be in more than one group. */
214 group_owner_entry = pa;
215 mask = mask_from_posix(pa->e_perm & mask_mask, flags);
216 nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE,
217 NFS4_ACE_IDENTIFIER_GROUP | eflag, mask,
218 NFS4_ACL_WHO_GROUP, 0);
221 while (pa->e_tag == ACL_GROUP) {
222 mask = mask_from_posix(pa->e_perm & mask_mask, flags);
223 nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE,
224 NFS4_ACE_IDENTIFIER_GROUP | eflag, mask,
225 NFS4_ACL_WHO_NAMED, pa->e_id);
231 pa = group_owner_entry;
232 mask = mask_from_posix(pa->e_perm, flags);
233 nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_DENIED_ACE_TYPE,
234 NFS4_ACE_IDENTIFIER_GROUP | eflag,
235 deny_mask(mask, flags), NFS4_ACL_WHO_GROUP, 0);
237 while (pa->e_tag == ACL_GROUP) {
238 mask = mask_from_posix(pa->e_perm, flags);
239 nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_DENIED_ACE_TYPE,
240 NFS4_ACE_IDENTIFIER_GROUP | eflag,
241 deny_mask(mask, flags), NFS4_ACL_WHO_NAMED, pa->e_id);
245 if (pa->e_tag == ACL_MASK)
247 BUG_ON(pa->e_tag != ACL_OTHER);
248 mask = mask_from_posix(pa->e_perm, flags);
249 nfs4_acl_add_pair(acl, eflag, mask, NFS4_ACL_WHO_EVERYONE, 0, flags);
253 sort_pacl_range(struct posix_acl *pacl, int start, int end) {
255 struct posix_acl_entry tmp;
257 /* We just do a bubble sort; easy to do in place, and we're not
258 * expecting acl's to be long enough to justify anything more. */
261 for (i = start; i < end; i++) {
262 if (pacl->a_entries[i].e_id
263 > pacl->a_entries[i+1].e_id) {
265 tmp = pacl->a_entries[i];
266 pacl->a_entries[i] = pacl->a_entries[i+1];
267 pacl->a_entries[i+1] = tmp;
274 sort_pacl(struct posix_acl *pacl)
276 /* posix_acl_valid requires that users and groups be in order
280 if (pacl->a_count <= 4)
281 return; /* no users or groups */
283 while (pacl->a_entries[i].e_tag == ACL_USER)
285 sort_pacl_range(pacl, 1, i-1);
287 BUG_ON(pacl->a_entries[i].e_tag != ACL_GROUP_OBJ);
289 while (pacl->a_entries[j].e_tag == ACL_GROUP)
291 sort_pacl_range(pacl, i, j-1);
296 * While processing the NFSv4 ACE, this maintains bitmasks representing
297 * which permission bits have been allowed and which denied to a given
299 struct posix_ace_state {
304 struct posix_user_ace_state {
306 struct posix_ace_state perms;
309 struct posix_ace_state_array {
311 struct posix_user_ace_state aces[];
315 * While processing the NFSv4 ACE, this maintains the partial permissions
316 * calculated so far: */
318 struct posix_acl_state {
319 struct posix_ace_state owner;
320 struct posix_ace_state group;
321 struct posix_ace_state other;
322 struct posix_ace_state everyone;
323 struct posix_ace_state mask; /* Deny unused in this case */
324 struct posix_ace_state_array *users;
325 struct posix_ace_state_array *groups;
329 init_state(struct posix_acl_state *state, int cnt)
333 memset(state, 0, sizeof(struct posix_acl_state));
335 * In the worst case, each individual acl could be for a distinct
336 * named user or group, but we don't no which, so we allocate
337 * enough space for either:
339 alloc = sizeof(struct posix_ace_state_array)
340 + cnt*sizeof(struct posix_ace_state);
341 state->users = kzalloc(alloc, GFP_KERNEL);
344 state->groups = kzalloc(alloc, GFP_KERNEL);
345 if (!state->groups) {
353 free_state(struct posix_acl_state *state) {
355 kfree(state->groups);
358 static inline void add_to_mask(struct posix_acl_state *state, struct posix_ace_state *astate)
360 state->mask.allow |= astate->allow;
364 * Certain bits (SYNCHRONIZE, DELETE, WRITE_OWNER, READ/WRITE_NAMED_ATTRS,
365 * READ_ATTRIBUTES, READ_ACL) are currently unenforceable and don't translate
366 * to traditional read/write/execute permissions.
368 * It's problematic to reject acls that use certain mode bits, because it
369 * places the burden on users to learn the rules about which bits one
370 * particular server sets, without giving the user a lot of help--we return an
371 * error that could mean any number of different things. To make matters
372 * worse, the problematic bits might be introduced by some application that's
373 * automatically mapping from some other acl model.
375 * So wherever possible we accept anything, possibly erring on the side of
376 * denying more permissions than necessary.
378 * However we do reject *explicit* DENY's of a few bits representing
379 * permissions we could never deny:
382 static inline int check_deny(u32 mask, int isowner)
384 if (mask & (NFS4_ACE_READ_ATTRIBUTES | NFS4_ACE_READ_ACL))
388 if (mask & (NFS4_ACE_WRITE_ATTRIBUTES | NFS4_ACE_WRITE_ACL))
393 static struct posix_acl *
394 posix_state_to_acl(struct posix_acl_state *state, unsigned int flags)
396 struct posix_acl_entry *pace;
397 struct posix_acl *pacl;
401 nace = 4 + state->users->n + state->groups->n;
402 pacl = posix_acl_alloc(nace, GFP_KERNEL);
404 return ERR_PTR(-ENOMEM);
406 pace = pacl->a_entries;
407 pace->e_tag = ACL_USER_OBJ;
408 error = check_deny(state->owner.deny, 1);
411 low_mode_from_nfs4(state->owner.allow, &pace->e_perm, flags);
412 pace->e_id = ACL_UNDEFINED_ID;
414 for (i=0; i < state->users->n; i++) {
416 pace->e_tag = ACL_USER;
417 error = check_deny(state->users->aces[i].perms.deny, 0);
420 low_mode_from_nfs4(state->users->aces[i].perms.allow,
421 &pace->e_perm, flags);
422 pace->e_id = state->users->aces[i].uid;
423 add_to_mask(state, &state->users->aces[i].perms);
427 pace->e_tag = ACL_GROUP_OBJ;
428 error = check_deny(state->group.deny, 0);
431 low_mode_from_nfs4(state->group.allow, &pace->e_perm, flags);
432 pace->e_id = ACL_UNDEFINED_ID;
433 add_to_mask(state, &state->group);
435 for (i=0; i < state->groups->n; i++) {
437 pace->e_tag = ACL_GROUP;
438 error = check_deny(state->groups->aces[i].perms.deny, 0);
441 low_mode_from_nfs4(state->groups->aces[i].perms.allow,
442 &pace->e_perm, flags);
443 pace->e_id = state->groups->aces[i].uid;
444 add_to_mask(state, &state->groups->aces[i].perms);
448 pace->e_tag = ACL_MASK;
449 low_mode_from_nfs4(state->mask.allow, &pace->e_perm, flags);
450 pace->e_id = ACL_UNDEFINED_ID;
453 pace->e_tag = ACL_OTHER;
454 error = check_deny(state->other.deny, 0);
457 low_mode_from_nfs4(state->other.allow, &pace->e_perm, flags);
458 pace->e_id = ACL_UNDEFINED_ID;
462 posix_acl_release(pacl);
463 return ERR_PTR(error);
466 static inline void allow_bits(struct posix_ace_state *astate, u32 mask)
468 /* Allow all bits in the mask not already denied: */
469 astate->allow |= mask & ~astate->deny;
472 static inline void deny_bits(struct posix_ace_state *astate, u32 mask)
474 /* Deny all bits in the mask not already allowed: */
475 astate->deny |= mask & ~astate->allow;
478 static int find_uid(struct posix_acl_state *state, struct posix_ace_state_array *a, uid_t uid)
482 for (i = 0; i < a->n; i++)
483 if (a->aces[i].uid == uid)
487 a->aces[i].uid = uid;
488 a->aces[i].perms.allow = state->everyone.allow;
489 a->aces[i].perms.deny = state->everyone.deny;
494 static void deny_bits_array(struct posix_ace_state_array *a, u32 mask)
498 for (i=0; i < a->n; i++)
499 deny_bits(&a->aces[i].perms, mask);
502 static void allow_bits_array(struct posix_ace_state_array *a, u32 mask)
506 for (i=0; i < a->n; i++)
507 allow_bits(&a->aces[i].perms, mask);
510 static void process_one_v4_ace(struct posix_acl_state *state,
511 struct nfs4_ace *ace)
513 u32 mask = ace->access_mask;
516 switch (ace2type(ace)) {
518 if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
519 allow_bits(&state->owner, mask);
521 deny_bits(&state->owner, mask);
525 i = find_uid(state, state->users, ace->who);
526 if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
527 allow_bits(&state->users->aces[i].perms, mask);
529 deny_bits(&state->users->aces[i].perms, mask);
530 mask = state->users->aces[i].perms.deny;
531 deny_bits(&state->owner, mask);
535 if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
536 allow_bits(&state->group, mask);
538 deny_bits(&state->group, mask);
539 mask = state->group.deny;
540 deny_bits(&state->owner, mask);
541 deny_bits(&state->everyone, mask);
542 deny_bits_array(state->users, mask);
543 deny_bits_array(state->groups, mask);
547 i = find_uid(state, state->groups, ace->who);
548 if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
549 allow_bits(&state->groups->aces[i].perms, mask);
551 deny_bits(&state->groups->aces[i].perms, mask);
552 mask = state->groups->aces[i].perms.deny;
553 deny_bits(&state->owner, mask);
554 deny_bits(&state->group, mask);
555 deny_bits(&state->everyone, mask);
556 deny_bits_array(state->users, mask);
557 deny_bits_array(state->groups, mask);
561 if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
562 allow_bits(&state->owner, mask);
563 allow_bits(&state->group, mask);
564 allow_bits(&state->other, mask);
565 allow_bits(&state->everyone, mask);
566 allow_bits_array(state->users, mask);
567 allow_bits_array(state->groups, mask);
569 deny_bits(&state->owner, mask);
570 deny_bits(&state->group, mask);
571 deny_bits(&state->other, mask);
572 deny_bits(&state->everyone, mask);
573 deny_bits_array(state->users, mask);
574 deny_bits_array(state->groups, mask);
579 int nfs4_acl_nfsv4_to_posix(struct nfs4_acl *acl, struct posix_acl **pacl,
580 struct posix_acl **dpacl, unsigned int flags)
582 struct posix_acl_state effective_acl_state, default_acl_state;
583 struct nfs4_ace *ace;
586 ret = init_state(&effective_acl_state, acl->naces);
589 ret = init_state(&default_acl_state, acl->naces);
593 for (ace = acl->aces; ace < acl->aces + acl->naces; ace++) {
594 if (ace->type != NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE &&
595 ace->type != NFS4_ACE_ACCESS_DENIED_ACE_TYPE)
597 if (ace->flag & ~NFS4_SUPPORTED_FLAGS)
599 if ((ace->flag & NFS4_INHERITANCE_FLAGS) == 0) {
600 process_one_v4_ace(&effective_acl_state, ace);
603 if (!(flags & NFS4_ACL_DIR))
606 * Note that when only one of FILE_INHERIT or DIRECTORY_INHERIT
607 * is set, we're effectively turning on the other. That's OK,
608 * according to rfc 3530.
610 process_one_v4_ace(&default_acl_state, ace);
612 if (!(ace->flag & NFS4_ACE_INHERIT_ONLY_ACE))
613 process_one_v4_ace(&effective_acl_state, ace);
615 *pacl = posix_state_to_acl(&effective_acl_state, flags);
617 ret = PTR_ERR(*pacl);
620 *dpacl = posix_state_to_acl(&default_acl_state, flags);
621 if (IS_ERR(*dpacl)) {
622 ret = PTR_ERR(*dpacl);
623 posix_acl_release(*pacl);
630 free_state(&default_acl_state);
632 free_state(&effective_acl_state);
637 ace2type(struct nfs4_ace *ace)
639 switch (ace->whotype) {
640 case NFS4_ACL_WHO_NAMED:
641 return (ace->flag & NFS4_ACE_IDENTIFIER_GROUP ?
642 ACL_GROUP : ACL_USER);
643 case NFS4_ACL_WHO_OWNER:
645 case NFS4_ACL_WHO_GROUP:
646 return ACL_GROUP_OBJ;
647 case NFS4_ACL_WHO_EVERYONE:
654 EXPORT_SYMBOL(nfs4_acl_posix_to_nfsv4);
655 EXPORT_SYMBOL(nfs4_acl_nfsv4_to_posix);
660 struct nfs4_acl *acl;
662 acl = kmalloc(sizeof(*acl) + n*sizeof(struct nfs4_ace), GFP_KERNEL);
670 nfs4_acl_add_ace(struct nfs4_acl *acl, u32 type, u32 flag, u32 access_mask,
671 int whotype, uid_t who)
673 struct nfs4_ace *ace = acl->aces + acl->naces;
677 ace->access_mask = access_mask;
678 ace->whotype = whotype;
691 .stringlen = sizeof("OWNER@") - 1,
692 .type = NFS4_ACL_WHO_OWNER,
696 .stringlen = sizeof("GROUP@") - 1,
697 .type = NFS4_ACL_WHO_GROUP,
700 .string = "EVERYONE@",
701 .stringlen = sizeof("EVERYONE@") - 1,
702 .type = NFS4_ACL_WHO_EVERYONE,
707 nfs4_acl_get_whotype(char *p, u32 len)
711 for (i = 0; i < ARRAY_SIZE(s2t_map); i++) {
712 if (s2t_map[i].stringlen == len &&
713 0 == memcmp(s2t_map[i].string, p, len))
714 return s2t_map[i].type;
716 return NFS4_ACL_WHO_NAMED;
720 nfs4_acl_write_who(int who, char *p)
724 for (i = 0; i < ARRAY_SIZE(s2t_map); i++) {
725 if (s2t_map[i].type == who) {
726 memcpy(p, s2t_map[i].string, s2t_map[i].stringlen);
727 return s2t_map[i].stringlen;
734 EXPORT_SYMBOL(nfs4_acl_new);
735 EXPORT_SYMBOL(nfs4_acl_add_ace);
736 EXPORT_SYMBOL(nfs4_acl_get_whotype);
737 EXPORT_SYMBOL(nfs4_acl_write_who);