blob: ad88f1c0a4c3f5d5f05173aafba65f143e6ec0f2 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07002 * 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
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090037#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070038#include <linux/nfs_fs.h>
J. Bruce Fields2ca72e12011-01-04 17:37:15 -050039#include "acl.h"
Linus Torvalds1da177e2005-04-16 15:20:36 -070040
41
42/* mode bit translations: */
43#define NFS4_READ_MODE (NFS4_ACE_READ_DATA)
44#define NFS4_WRITE_MODE (NFS4_ACE_WRITE_DATA | NFS4_ACE_APPEND_DATA)
45#define NFS4_EXECUTE_MODE NFS4_ACE_EXECUTE
46#define NFS4_ANYONE_MODE (NFS4_ACE_READ_ATTRIBUTES | NFS4_ACE_READ_ACL | NFS4_ACE_SYNCHRONIZE)
47#define NFS4_OWNER_MODE (NFS4_ACE_WRITE_ATTRIBUTES | NFS4_ACE_WRITE_ACL)
48
49/* We don't support these bits; insist they be neither allowed nor denied */
50#define NFS4_MASK_UNSUPP (NFS4_ACE_DELETE | NFS4_ACE_WRITE_OWNER \
51 | NFS4_ACE_READ_NAMED_ATTRS | NFS4_ACE_WRITE_NAMED_ATTRS)
52
53/* flags used to simulate posix default ACLs */
54#define NFS4_INHERITANCE_FLAGS (NFS4_ACE_FILE_INHERIT_ACE \
J. Bruce Fields7bdfa682007-02-16 01:28:28 -080055 | NFS4_ACE_DIRECTORY_INHERIT_ACE)
Linus Torvalds1da177e2005-04-16 15:20:36 -070056
J. Bruce Fields7bdfa682007-02-16 01:28:28 -080057#define NFS4_SUPPORTED_FLAGS (NFS4_INHERITANCE_FLAGS \
58 | NFS4_ACE_INHERIT_ONLY_ACE \
59 | NFS4_ACE_IDENTIFIER_GROUP)
J.Bruce Fieldsb548edc2006-10-04 02:16:12 -070060
Linus Torvalds1da177e2005-04-16 15:20:36 -070061#define MASK_EQUAL(mask1, mask2) \
62 ( ((mask1) & NFS4_ACE_MASK_ALL) == ((mask2) & NFS4_ACE_MASK_ALL) )
63
64static u32
65mask_from_posix(unsigned short perm, unsigned int flags)
66{
67 int mask = NFS4_ANYONE_MODE;
68
69 if (flags & NFS4_ACL_OWNER)
70 mask |= NFS4_OWNER_MODE;
71 if (perm & ACL_READ)
72 mask |= NFS4_READ_MODE;
73 if (perm & ACL_WRITE)
74 mask |= NFS4_WRITE_MODE;
75 if ((perm & ACL_WRITE) && (flags & NFS4_ACL_DIR))
76 mask |= NFS4_ACE_DELETE_CHILD;
77 if (perm & ACL_EXECUTE)
78 mask |= NFS4_EXECUTE_MODE;
79 return mask;
80}
81
82static u32
J. Bruce Fieldsbec50c42007-02-16 01:28:36 -080083deny_mask_from_posix(unsigned short perm, u32 flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -070084{
J. Bruce Fieldsbec50c42007-02-16 01:28:36 -080085 u32 mask = 0;
86
87 if (perm & ACL_READ)
88 mask |= NFS4_READ_MODE;
89 if (perm & ACL_WRITE)
90 mask |= NFS4_WRITE_MODE;
91 if ((perm & ACL_WRITE) && (flags & NFS4_ACL_DIR))
92 mask |= NFS4_ACE_DELETE_CHILD;
93 if (perm & ACL_EXECUTE)
94 mask |= NFS4_EXECUTE_MODE;
95 return mask;
Linus Torvalds1da177e2005-04-16 15:20:36 -070096}
97
98/* XXX: modify functions to return NFS errors; they're only ever
99 * used by nfs code, after all.... */
100
J.Bruce Fields09229ed2006-10-04 02:16:11 -0700101/* We only map from NFSv4 to POSIX ACLs when setting ACLs, when we err on the
102 * side of being more restrictive, so the mode bit mapping below is
103 * pessimistic. An optimistic version would be needed to handle DENY's,
104 * but we espect to coalesce all ALLOWs and DENYs before mapping to mode
105 * bits. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106
J.Bruce Fields09229ed2006-10-04 02:16:11 -0700107static void
108low_mode_from_nfs4(u32 perm, unsigned short *mode, unsigned int flags)
109{
110 u32 write_mode = NFS4_WRITE_MODE;
111
112 if (flags & NFS4_ACL_DIR)
113 write_mode |= NFS4_ACE_DELETE_CHILD;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114 *mode = 0;
115 if ((perm & NFS4_READ_MODE) == NFS4_READ_MODE)
116 *mode |= ACL_READ;
J.Bruce Fields09229ed2006-10-04 02:16:11 -0700117 if ((perm & write_mode) == write_mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118 *mode |= ACL_WRITE;
119 if ((perm & NFS4_EXECUTE_MODE) == NFS4_EXECUTE_MODE)
120 *mode |= ACL_EXECUTE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121}
122
123struct ace_container {
124 struct nfs4_ace *ace;
125 struct list_head ace_l;
126};
127
128static short ace2type(struct nfs4_ace *);
J. Bruce Fields28e05dd2007-02-16 01:28:30 -0800129static void _posix_to_nfsv4_one(struct posix_acl *, struct nfs4_acl *,
130 unsigned int);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131
132struct nfs4_acl *
133nfs4_acl_posix_to_nfsv4(struct posix_acl *pacl, struct posix_acl *dpacl,
134 unsigned int flags)
135{
136 struct nfs4_acl *acl;
J. Bruce Fields28e05dd2007-02-16 01:28:30 -0800137 int size = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138
J. Bruce Fields28e05dd2007-02-16 01:28:30 -0800139 if (pacl) {
140 if (posix_acl_valid(pacl) < 0)
141 return ERR_PTR(-EINVAL);
142 size += 2*pacl->a_count;
143 }
144 if (dpacl) {
145 if (posix_acl_valid(dpacl) < 0)
146 return ERR_PTR(-EINVAL);
147 size += 2*dpacl->a_count;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700148 }
149
J. Bruce Fields28e05dd2007-02-16 01:28:30 -0800150 /* Allocate for worst case: one (deny, allow) pair each: */
151 acl = nfs4_acl_new(size);
152 if (acl == NULL)
153 return ERR_PTR(-ENOMEM);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154
J. Bruce Fields28e05dd2007-02-16 01:28:30 -0800155 if (pacl)
156 _posix_to_nfsv4_one(pacl, acl, flags & ~NFS4_ACL_TYPE_DEFAULT);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157
J. Bruce Fields28e05dd2007-02-16 01:28:30 -0800158 if (dpacl)
159 _posix_to_nfsv4_one(dpacl, acl, flags | NFS4_ACL_TYPE_DEFAULT);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160
161 return acl;
162}
163
J. Bruce Fieldsbec50c42007-02-16 01:28:36 -0800164struct posix_acl_summary {
165 unsigned short owner;
166 unsigned short users;
167 unsigned short group;
168 unsigned short groups;
169 unsigned short other;
170 unsigned short mask;
171};
172
J. Bruce Fields28e05dd2007-02-16 01:28:30 -0800173static void
J. Bruce Fieldsbec50c42007-02-16 01:28:36 -0800174summarize_posix_acl(struct posix_acl *acl, struct posix_acl_summary *pas)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175{
J. Bruce Fieldsbec50c42007-02-16 01:28:36 -0800176 struct posix_acl_entry *pa, *pe;
J. Bruce Fieldsf7fede42007-07-17 04:04:36 -0700177
178 /*
179 * Only pas.users and pas.groups need initialization; previous
180 * posix_acl_valid() calls ensure that the other fields will be
181 * initialized in the following loop. But, just to placate gcc:
182 */
183 memset(pas, 0, sizeof(*pas));
J. Bruce Fieldsbec50c42007-02-16 01:28:36 -0800184 pas->mask = 07;
185
186 pe = acl->a_entries + acl->a_count;
187
188 FOREACH_ACL_ENTRY(pa, acl, pe) {
189 switch (pa->e_tag) {
190 case ACL_USER_OBJ:
191 pas->owner = pa->e_perm;
192 break;
193 case ACL_GROUP_OBJ:
194 pas->group = pa->e_perm;
195 break;
196 case ACL_USER:
197 pas->users |= pa->e_perm;
198 break;
199 case ACL_GROUP:
200 pas->groups |= pa->e_perm;
201 break;
202 case ACL_OTHER:
203 pas->other = pa->e_perm;
204 break;
205 case ACL_MASK:
206 pas->mask = pa->e_perm;
207 break;
208 }
209 }
210 /* We'll only care about effective permissions: */
211 pas->users &= pas->mask;
212 pas->group &= pas->mask;
213 pas->groups &= pas->mask;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214}
215
216/* We assume the acl has been verified with posix_acl_valid. */
J. Bruce Fields28e05dd2007-02-16 01:28:30 -0800217static void
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218_posix_to_nfsv4_one(struct posix_acl *pacl, struct nfs4_acl *acl,
219 unsigned int flags)
220{
J. Bruce Fieldsbec50c42007-02-16 01:28:36 -0800221 struct posix_acl_entry *pa, *group_owner_entry;
222 struct nfs4_ace *ace;
223 struct posix_acl_summary pas;
224 unsigned short deny;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700225 int eflag = ((flags & NFS4_ACL_TYPE_DEFAULT) ?
Bruce Fields54c04402007-03-26 21:32:09 -0800226 NFS4_INHERITANCE_FLAGS | NFS4_ACE_INHERIT_ONLY_ACE : 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227
228 BUG_ON(pacl->a_count < 3);
J. Bruce Fieldsbec50c42007-02-16 01:28:36 -0800229 summarize_posix_acl(pacl, &pas);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230
231 pa = pacl->a_entries;
J. Bruce Fieldsbec50c42007-02-16 01:28:36 -0800232 ace = acl->aces + acl->naces;
233
234 /* We could deny everything not granted by the owner: */
235 deny = ~pas.owner;
236 /*
237 * but it is equivalent (and simpler) to deny only what is not
238 * granted by later entries:
239 */
240 deny &= pas.users | pas.group | pas.groups | pas.other;
241 if (deny) {
242 ace->type = NFS4_ACE_ACCESS_DENIED_ACE_TYPE;
243 ace->flag = eflag;
244 ace->access_mask = deny_mask_from_posix(deny, flags);
245 ace->whotype = NFS4_ACL_WHO_OWNER;
246 ace++;
247 acl->naces++;
248 }
249
250 ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
251 ace->flag = eflag;
252 ace->access_mask = mask_from_posix(pa->e_perm, flags | NFS4_ACL_OWNER);
253 ace->whotype = NFS4_ACL_WHO_OWNER;
254 ace++;
255 acl->naces++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256 pa++;
257
258 while (pa->e_tag == ACL_USER) {
J. Bruce Fieldsbec50c42007-02-16 01:28:36 -0800259 deny = ~(pa->e_perm & pas.mask);
260 deny &= pas.groups | pas.group | pas.other;
261 if (deny) {
262 ace->type = NFS4_ACE_ACCESS_DENIED_ACE_TYPE;
263 ace->flag = eflag;
264 ace->access_mask = deny_mask_from_posix(deny, flags);
265 ace->whotype = NFS4_ACL_WHO_NAMED;
266 ace->who = pa->e_id;
267 ace++;
268 acl->naces++;
269 }
270 ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
271 ace->flag = eflag;
272 ace->access_mask = mask_from_posix(pa->e_perm & pas.mask,
273 flags);
274 ace->whotype = NFS4_ACL_WHO_NAMED;
275 ace->who = pa->e_id;
276 ace++;
277 acl->naces++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278 pa++;
279 }
280
281 /* In the case of groups, we apply allow ACEs first, then deny ACEs,
282 * since a user can be in more than one group. */
283
284 /* allow ACEs */
285
Linus Torvalds1da177e2005-04-16 15:20:36 -0700286 group_owner_entry = pa;
J. Bruce Fieldsbec50c42007-02-16 01:28:36 -0800287
288 ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
289 ace->flag = eflag;
290 ace->access_mask = mask_from_posix(pas.group, flags);
291 ace->whotype = NFS4_ACL_WHO_GROUP;
292 ace++;
293 acl->naces++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294 pa++;
295
296 while (pa->e_tag == ACL_GROUP) {
J. Bruce Fieldsbec50c42007-02-16 01:28:36 -0800297 ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
298 ace->flag = eflag | NFS4_ACE_IDENTIFIER_GROUP;
299 ace->access_mask = mask_from_posix(pa->e_perm & pas.mask,
300 flags);
301 ace->whotype = NFS4_ACL_WHO_NAMED;
302 ace->who = pa->e_id;
303 ace++;
304 acl->naces++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700305 pa++;
306 }
307
308 /* deny ACEs */
309
310 pa = group_owner_entry;
J. Bruce Fieldsbec50c42007-02-16 01:28:36 -0800311
312 deny = ~pas.group & pas.other;
313 if (deny) {
314 ace->type = NFS4_ACE_ACCESS_DENIED_ACE_TYPE;
Frank Filzd8d0b852009-08-27 17:35:41 -0400315 ace->flag = eflag;
J. Bruce Fieldsbec50c42007-02-16 01:28:36 -0800316 ace->access_mask = deny_mask_from_posix(deny, flags);
317 ace->whotype = NFS4_ACL_WHO_GROUP;
318 ace++;
319 acl->naces++;
320 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321 pa++;
J. Bruce Fieldsbec50c42007-02-16 01:28:36 -0800322
Linus Torvalds1da177e2005-04-16 15:20:36 -0700323 while (pa->e_tag == ACL_GROUP) {
J. Bruce Fieldsbec50c42007-02-16 01:28:36 -0800324 deny = ~(pa->e_perm & pas.mask);
325 deny &= pas.other;
326 if (deny) {
327 ace->type = NFS4_ACE_ACCESS_DENIED_ACE_TYPE;
328 ace->flag = eflag | NFS4_ACE_IDENTIFIER_GROUP;
Frank Filz55bb55d2009-08-14 15:02:30 -0700329 ace->access_mask = deny_mask_from_posix(deny, flags);
J. Bruce Fieldsbec50c42007-02-16 01:28:36 -0800330 ace->whotype = NFS4_ACL_WHO_NAMED;
331 ace->who = pa->e_id;
332 ace++;
333 acl->naces++;
334 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335 pa++;
336 }
337
338 if (pa->e_tag == ACL_MASK)
339 pa++;
J. Bruce Fieldsbec50c42007-02-16 01:28:36 -0800340 ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
341 ace->flag = eflag;
342 ace->access_mask = mask_from_posix(pa->e_perm, flags);
343 ace->whotype = NFS4_ACL_WHO_EVERYONE;
344 acl->naces++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700345}
346
347static void
348sort_pacl_range(struct posix_acl *pacl, int start, int end) {
349 int sorted = 0, i;
350 struct posix_acl_entry tmp;
351
352 /* We just do a bubble sort; easy to do in place, and we're not
353 * expecting acl's to be long enough to justify anything more. */
354 while (!sorted) {
355 sorted = 1;
356 for (i = start; i < end; i++) {
357 if (pacl->a_entries[i].e_id
358 > pacl->a_entries[i+1].e_id) {
359 sorted = 0;
360 tmp = pacl->a_entries[i];
361 pacl->a_entries[i] = pacl->a_entries[i+1];
362 pacl->a_entries[i+1] = tmp;
363 }
364 }
365 }
366}
367
368static void
369sort_pacl(struct posix_acl *pacl)
370{
371 /* posix_acl_valid requires that users and groups be in order
372 * by uid/gid. */
373 int i, j;
374
375 if (pacl->a_count <= 4)
376 return; /* no users or groups */
377 i = 1;
378 while (pacl->a_entries[i].e_tag == ACL_USER)
379 i++;
380 sort_pacl_range(pacl, 1, i-1);
381
382 BUG_ON(pacl->a_entries[i].e_tag != ACL_GROUP_OBJ);
Frank Filzaba24d72009-10-21 16:45:02 -0700383 j = ++i;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700384 while (pacl->a_entries[j].e_tag == ACL_GROUP)
385 j++;
386 sort_pacl_range(pacl, i, j-1);
387 return;
388}
389
J.Bruce Fields09229ed2006-10-04 02:16:11 -0700390/*
391 * While processing the NFSv4 ACE, this maintains bitmasks representing
392 * which permission bits have been allowed and which denied to a given
393 * entity: */
394struct posix_ace_state {
395 u32 allow;
396 u32 deny;
397};
398
399struct posix_user_ace_state {
400 uid_t uid;
401 struct posix_ace_state perms;
402};
403
404struct posix_ace_state_array {
405 int n;
406 struct posix_user_ace_state aces[];
407};
408
409/*
410 * While processing the NFSv4 ACE, this maintains the partial permissions
411 * calculated so far: */
412
413struct posix_acl_state {
J. Bruce Fields3160a712007-02-16 01:28:37 -0800414 int empty;
J.Bruce Fields09229ed2006-10-04 02:16:11 -0700415 struct posix_ace_state owner;
416 struct posix_ace_state group;
417 struct posix_ace_state other;
418 struct posix_ace_state everyone;
419 struct posix_ace_state mask; /* Deny unused in this case */
420 struct posix_ace_state_array *users;
421 struct posix_ace_state_array *groups;
422};
Linus Torvalds1da177e2005-04-16 15:20:36 -0700423
424static int
J.Bruce Fields09229ed2006-10-04 02:16:11 -0700425init_state(struct posix_acl_state *state, int cnt)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700426{
J.Bruce Fields09229ed2006-10-04 02:16:11 -0700427 int alloc;
428
429 memset(state, 0, sizeof(struct posix_acl_state));
J. Bruce Fields3160a712007-02-16 01:28:37 -0800430 state->empty = 1;
J.Bruce Fields09229ed2006-10-04 02:16:11 -0700431 /*
432 * In the worst case, each individual acl could be for a distinct
433 * named user or group, but we don't no which, so we allocate
434 * enough space for either:
435 */
436 alloc = sizeof(struct posix_ace_state_array)
J. Bruce Fields91b80962008-08-29 19:18:45 -0400437 + cnt*sizeof(struct posix_user_ace_state);
J.Bruce Fields09229ed2006-10-04 02:16:11 -0700438 state->users = kzalloc(alloc, GFP_KERNEL);
439 if (!state->users)
440 return -ENOMEM;
441 state->groups = kzalloc(alloc, GFP_KERNEL);
442 if (!state->groups) {
443 kfree(state->users);
444 return -ENOMEM;
445 }
446 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700447}
448
J.Bruce Fields09229ed2006-10-04 02:16:11 -0700449static void
450free_state(struct posix_acl_state *state) {
451 kfree(state->users);
452 kfree(state->groups);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700453}
454
J.Bruce Fields09229ed2006-10-04 02:16:11 -0700455static inline void add_to_mask(struct posix_acl_state *state, struct posix_ace_state *astate)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700456{
J.Bruce Fields09229ed2006-10-04 02:16:11 -0700457 state->mask.allow |= astate->allow;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700458}
459
J.Bruce Fields09229ed2006-10-04 02:16:11 -0700460/*
461 * Certain bits (SYNCHRONIZE, DELETE, WRITE_OWNER, READ/WRITE_NAMED_ATTRS,
462 * READ_ATTRIBUTES, READ_ACL) are currently unenforceable and don't translate
463 * to traditional read/write/execute permissions.
464 *
465 * It's problematic to reject acls that use certain mode bits, because it
466 * places the burden on users to learn the rules about which bits one
467 * particular server sets, without giving the user a lot of help--we return an
468 * error that could mean any number of different things. To make matters
469 * worse, the problematic bits might be introduced by some application that's
470 * automatically mapping from some other acl model.
471 *
472 * So wherever possible we accept anything, possibly erring on the side of
473 * denying more permissions than necessary.
474 *
475 * However we do reject *explicit* DENY's of a few bits representing
476 * permissions we could never deny:
477 */
478
479static inline int check_deny(u32 mask, int isowner)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700480{
J.Bruce Fields09229ed2006-10-04 02:16:11 -0700481 if (mask & (NFS4_ACE_READ_ATTRIBUTES | NFS4_ACE_READ_ACL))
482 return -EINVAL;
483 if (!isowner)
484 return 0;
485 if (mask & (NFS4_ACE_WRITE_ATTRIBUTES | NFS4_ACE_WRITE_ACL))
486 return -EINVAL;
487 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700488}
489
J.Bruce Fields09229ed2006-10-04 02:16:11 -0700490static struct posix_acl *
491posix_state_to_acl(struct posix_acl_state *state, unsigned int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700492{
J.Bruce Fields09229ed2006-10-04 02:16:11 -0700493 struct posix_acl_entry *pace;
494 struct posix_acl *pacl;
495 int nace;
496 int i, error = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700497
J. Bruce Fields3160a712007-02-16 01:28:37 -0800498 /*
499 * ACLs with no ACEs are treated differently in the inheritable
500 * and effective cases: when there are no inheritable ACEs, we
501 * set a zero-length default posix acl:
502 */
503 if (state->empty && (flags & NFS4_ACL_TYPE_DEFAULT)) {
504 pacl = posix_acl_alloc(0, GFP_KERNEL);
505 return pacl ? pacl : ERR_PTR(-ENOMEM);
506 }
507 /*
508 * When there are no effective ACEs, the following will end
509 * up setting a 3-element effective posix ACL with all
510 * permissions zero.
511 */
J.Bruce Fields09229ed2006-10-04 02:16:11 -0700512 nace = 4 + state->users->n + state->groups->n;
513 pacl = posix_acl_alloc(nace, GFP_KERNEL);
514 if (!pacl)
515 return ERR_PTR(-ENOMEM);
516
517 pace = pacl->a_entries;
518 pace->e_tag = ACL_USER_OBJ;
519 error = check_deny(state->owner.deny, 1);
520 if (error)
521 goto out_err;
522 low_mode_from_nfs4(state->owner.allow, &pace->e_perm, flags);
523 pace->e_id = ACL_UNDEFINED_ID;
524
525 for (i=0; i < state->users->n; i++) {
526 pace++;
527 pace->e_tag = ACL_USER;
528 error = check_deny(state->users->aces[i].perms.deny, 0);
529 if (error)
530 goto out_err;
531 low_mode_from_nfs4(state->users->aces[i].perms.allow,
532 &pace->e_perm, flags);
533 pace->e_id = state->users->aces[i].uid;
534 add_to_mask(state, &state->users->aces[i].perms);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700535 }
J.Bruce Fields09229ed2006-10-04 02:16:11 -0700536
537 pace++;
538 pace->e_tag = ACL_GROUP_OBJ;
539 error = check_deny(state->group.deny, 0);
540 if (error)
541 goto out_err;
542 low_mode_from_nfs4(state->group.allow, &pace->e_perm, flags);
543 pace->e_id = ACL_UNDEFINED_ID;
544 add_to_mask(state, &state->group);
545
546 for (i=0; i < state->groups->n; i++) {
547 pace++;
548 pace->e_tag = ACL_GROUP;
549 error = check_deny(state->groups->aces[i].perms.deny, 0);
550 if (error)
551 goto out_err;
552 low_mode_from_nfs4(state->groups->aces[i].perms.allow,
553 &pace->e_perm, flags);
554 pace->e_id = state->groups->aces[i].uid;
555 add_to_mask(state, &state->groups->aces[i].perms);
556 }
557
558 pace++;
559 pace->e_tag = ACL_MASK;
560 low_mode_from_nfs4(state->mask.allow, &pace->e_perm, flags);
561 pace->e_id = ACL_UNDEFINED_ID;
562
563 pace++;
564 pace->e_tag = ACL_OTHER;
565 error = check_deny(state->other.deny, 0);
566 if (error)
567 goto out_err;
568 low_mode_from_nfs4(state->other.allow, &pace->e_perm, flags);
569 pace->e_id = ACL_UNDEFINED_ID;
570
571 return pacl;
572out_err:
573 posix_acl_release(pacl);
574 return ERR_PTR(error);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700575}
576
J.Bruce Fields09229ed2006-10-04 02:16:11 -0700577static inline void allow_bits(struct posix_ace_state *astate, u32 mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700578{
J.Bruce Fields09229ed2006-10-04 02:16:11 -0700579 /* Allow all bits in the mask not already denied: */
580 astate->allow |= mask & ~astate->deny;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700581}
582
J.Bruce Fields09229ed2006-10-04 02:16:11 -0700583static inline void deny_bits(struct posix_ace_state *astate, u32 mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700584{
J.Bruce Fields09229ed2006-10-04 02:16:11 -0700585 /* Deny all bits in the mask not already allowed: */
586 astate->deny |= mask & ~astate->allow;
587}
588
589static int find_uid(struct posix_acl_state *state, struct posix_ace_state_array *a, uid_t uid)
590{
591 int i;
592
593 for (i = 0; i < a->n; i++)
594 if (a->aces[i].uid == uid)
595 return i;
596 /* Not found: */
597 a->n++;
598 a->aces[i].uid = uid;
599 a->aces[i].perms.allow = state->everyone.allow;
600 a->aces[i].perms.deny = state->everyone.deny;
601
602 return i;
603}
604
605static void deny_bits_array(struct posix_ace_state_array *a, u32 mask)
606{
607 int i;
608
609 for (i=0; i < a->n; i++)
610 deny_bits(&a->aces[i].perms, mask);
611}
612
613static void allow_bits_array(struct posix_ace_state_array *a, u32 mask)
614{
615 int i;
616
617 for (i=0; i < a->n; i++)
618 allow_bits(&a->aces[i].perms, mask);
619}
620
621static void process_one_v4_ace(struct posix_acl_state *state,
622 struct nfs4_ace *ace)
623{
624 u32 mask = ace->access_mask;
625 int i;
626
J. Bruce Fields3160a712007-02-16 01:28:37 -0800627 state->empty = 0;
628
J.Bruce Fields09229ed2006-10-04 02:16:11 -0700629 switch (ace2type(ace)) {
630 case ACL_USER_OBJ:
631 if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
632 allow_bits(&state->owner, mask);
633 } else {
634 deny_bits(&state->owner, mask);
635 }
636 break;
637 case ACL_USER:
638 i = find_uid(state, state->users, ace->who);
639 if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
640 allow_bits(&state->users->aces[i].perms, mask);
641 } else {
642 deny_bits(&state->users->aces[i].perms, mask);
643 mask = state->users->aces[i].perms.deny;
644 deny_bits(&state->owner, mask);
645 }
646 break;
647 case ACL_GROUP_OBJ:
648 if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
649 allow_bits(&state->group, mask);
650 } else {
651 deny_bits(&state->group, mask);
652 mask = state->group.deny;
653 deny_bits(&state->owner, mask);
654 deny_bits(&state->everyone, mask);
655 deny_bits_array(state->users, mask);
656 deny_bits_array(state->groups, mask);
657 }
658 break;
659 case ACL_GROUP:
660 i = find_uid(state, state->groups, ace->who);
661 if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
662 allow_bits(&state->groups->aces[i].perms, mask);
663 } else {
664 deny_bits(&state->groups->aces[i].perms, mask);
665 mask = state->groups->aces[i].perms.deny;
666 deny_bits(&state->owner, mask);
667 deny_bits(&state->group, mask);
668 deny_bits(&state->everyone, mask);
669 deny_bits_array(state->users, mask);
670 deny_bits_array(state->groups, mask);
671 }
672 break;
673 case ACL_OTHER:
674 if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
675 allow_bits(&state->owner, mask);
676 allow_bits(&state->group, mask);
677 allow_bits(&state->other, mask);
678 allow_bits(&state->everyone, mask);
679 allow_bits_array(state->users, mask);
680 allow_bits_array(state->groups, mask);
681 } else {
682 deny_bits(&state->owner, mask);
683 deny_bits(&state->group, mask);
684 deny_bits(&state->other, mask);
685 deny_bits(&state->everyone, mask);
686 deny_bits_array(state->users, mask);
687 deny_bits_array(state->groups, mask);
688 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700689 }
690}
691
J. Bruce Fields575a6292007-02-16 01:28:29 -0800692int nfs4_acl_nfsv4_to_posix(struct nfs4_acl *acl, struct posix_acl **pacl,
693 struct posix_acl **dpacl, unsigned int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700694{
J. Bruce Fields575a6292007-02-16 01:28:29 -0800695 struct posix_acl_state effective_acl_state, default_acl_state;
J.Bruce Fields09229ed2006-10-04 02:16:11 -0700696 struct nfs4_ace *ace;
697 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700698
J. Bruce Fields575a6292007-02-16 01:28:29 -0800699 ret = init_state(&effective_acl_state, acl->naces);
J.Bruce Fields09229ed2006-10-04 02:16:11 -0700700 if (ret)
J. Bruce Fields575a6292007-02-16 01:28:29 -0800701 return ret;
702 ret = init_state(&default_acl_state, acl->naces);
703 if (ret)
704 goto out_estate;
705 ret = -EINVAL;
J. Bruce Fields28e05dd2007-02-16 01:28:30 -0800706 for (ace = acl->aces; ace < acl->aces + acl->naces; ace++) {
J.Bruce Fields09229ed2006-10-04 02:16:11 -0700707 if (ace->type != NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE &&
708 ace->type != NFS4_ACE_ACCESS_DENIED_ACE_TYPE)
J. Bruce Fields575a6292007-02-16 01:28:29 -0800709 goto out_dstate;
J.Bruce Fieldsb548edc2006-10-04 02:16:12 -0700710 if (ace->flag & ~NFS4_SUPPORTED_FLAGS)
J. Bruce Fields575a6292007-02-16 01:28:29 -0800711 goto out_dstate;
J. Bruce Fields7bdfa682007-02-16 01:28:28 -0800712 if ((ace->flag & NFS4_INHERITANCE_FLAGS) == 0) {
J. Bruce Fields575a6292007-02-16 01:28:29 -0800713 process_one_v4_ace(&effective_acl_state, ace);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700714 continue;
J. Bruce Fields7bdfa682007-02-16 01:28:28 -0800715 }
J. Bruce Fields575a6292007-02-16 01:28:29 -0800716 if (!(flags & NFS4_ACL_DIR))
717 goto out_dstate;
J. Bruce Fields7bdfa682007-02-16 01:28:28 -0800718 /*
719 * Note that when only one of FILE_INHERIT or DIRECTORY_INHERIT
720 * is set, we're effectively turning on the other. That's OK,
721 * according to rfc 3530.
722 */
J. Bruce Fields575a6292007-02-16 01:28:29 -0800723 process_one_v4_ace(&default_acl_state, ace);
724
725 if (!(ace->flag & NFS4_ACE_INHERIT_ONLY_ACE))
726 process_one_v4_ace(&effective_acl_state, ace);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700727 }
J. Bruce Fields575a6292007-02-16 01:28:29 -0800728 *pacl = posix_state_to_acl(&effective_acl_state, flags);
729 if (IS_ERR(*pacl)) {
730 ret = PTR_ERR(*pacl);
J. Bruce Fields4b2ca382007-07-17 04:04:37 -0700731 *pacl = NULL;
J. Bruce Fields575a6292007-02-16 01:28:29 -0800732 goto out_dstate;
733 }
J. Bruce Fields3160a712007-02-16 01:28:37 -0800734 *dpacl = posix_state_to_acl(&default_acl_state,
735 flags | NFS4_ACL_TYPE_DEFAULT);
J. Bruce Fields575a6292007-02-16 01:28:29 -0800736 if (IS_ERR(*dpacl)) {
737 ret = PTR_ERR(*dpacl);
J. Bruce Fields4b2ca382007-07-17 04:04:37 -0700738 *dpacl = NULL;
J. Bruce Fields575a6292007-02-16 01:28:29 -0800739 posix_acl_release(*pacl);
J. Bruce Fields4b2ca382007-07-17 04:04:37 -0700740 *pacl = NULL;
J. Bruce Fields575a6292007-02-16 01:28:29 -0800741 goto out_dstate;
742 }
743 sort_pacl(*pacl);
744 sort_pacl(*dpacl);
745 ret = 0;
746out_dstate:
747 free_state(&default_acl_state);
748out_estate:
749 free_state(&effective_acl_state);
750 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700751}
752
753static short
754ace2type(struct nfs4_ace *ace)
755{
756 switch (ace->whotype) {
757 case NFS4_ACL_WHO_NAMED:
758 return (ace->flag & NFS4_ACE_IDENTIFIER_GROUP ?
759 ACL_GROUP : ACL_USER);
760 case NFS4_ACL_WHO_OWNER:
761 return ACL_USER_OBJ;
762 case NFS4_ACL_WHO_GROUP:
763 return ACL_GROUP_OBJ;
764 case NFS4_ACL_WHO_EVERYONE:
765 return ACL_OTHER;
766 }
767 BUG();
768 return -1;
769}
770
771EXPORT_SYMBOL(nfs4_acl_posix_to_nfsv4);
772EXPORT_SYMBOL(nfs4_acl_nfsv4_to_posix);
773
774struct nfs4_acl *
J. Bruce Fields28e05dd2007-02-16 01:28:30 -0800775nfs4_acl_new(int n)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700776{
777 struct nfs4_acl *acl;
778
J. Bruce Fields28e05dd2007-02-16 01:28:30 -0800779 acl = kmalloc(sizeof(*acl) + n*sizeof(struct nfs4_ace), GFP_KERNEL);
780 if (acl == NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700781 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700782 acl->naces = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700783 return acl;
784}
785
Linus Torvalds1da177e2005-04-16 15:20:36 -0700786static struct {
787 char *string;
788 int stringlen;
789 int type;
790} s2t_map[] = {
791 {
792 .string = "OWNER@",
793 .stringlen = sizeof("OWNER@") - 1,
794 .type = NFS4_ACL_WHO_OWNER,
795 },
796 {
797 .string = "GROUP@",
798 .stringlen = sizeof("GROUP@") - 1,
799 .type = NFS4_ACL_WHO_GROUP,
800 },
801 {
802 .string = "EVERYONE@",
803 .stringlen = sizeof("EVERYONE@") - 1,
804 .type = NFS4_ACL_WHO_EVERYONE,
805 },
806};
807
808int
809nfs4_acl_get_whotype(char *p, u32 len)
810{
811 int i;
812
Tobias Klausere8c96f82006-03-24 03:15:34 -0800813 for (i = 0; i < ARRAY_SIZE(s2t_map); i++) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700814 if (s2t_map[i].stringlen == len &&
815 0 == memcmp(s2t_map[i].string, p, len))
816 return s2t_map[i].type;
817 }
818 return NFS4_ACL_WHO_NAMED;
819}
820
821int
822nfs4_acl_write_who(int who, char *p)
823{
824 int i;
825
Tobias Klausere8c96f82006-03-24 03:15:34 -0800826 for (i = 0; i < ARRAY_SIZE(s2t_map); i++) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700827 if (s2t_map[i].type == who) {
828 memcpy(p, s2t_map[i].string, s2t_map[i].stringlen);
829 return s2t_map[i].stringlen;
830 }
831 }
832 BUG();
833 return -1;
834}
835
Linus Torvalds1da177e2005-04-16 15:20:36 -0700836EXPORT_SYMBOL(nfs4_acl_new);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700837EXPORT_SYMBOL(nfs4_acl_get_whotype);
838EXPORT_SYMBOL(nfs4_acl_write_who);