fs/nfsd/nfs4acl.c

   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
  71 static u32
  72 mask_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
  89 static u32
  90 deny_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
 114 static void
 115 low_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
 130 struct ace_container {
 131         struct nfs4_ace  *ace;
 132         struct list_head  ace_l;
 133 };
 134
 135 static short ace2type(struct nfs4_ace *);
 136 static void _posix_to_nfsv4_one(struct posix_acl *, struct nfs4_acl *,
 137                                 unsigned int);
 138
 139 int
 140 nfsd4_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                 /* allocate for worst case: one (deny, allow) pair each: */
 155                 size += 2 * pacl->a_count;
 156         }
 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         } else {
 164                 dpacl = NULL;
 165         }
 166
 167         *acl = nfs4_acl_new(size);
 168         if (*acl == NULL) {
 169                 error = -ENOMEM;
 170                 goto out;
 171         }
 172
 173         if (pacl)
 174                 _posix_to_nfsv4_one(pacl, *acl, flags & ~NFS4_ACL_TYPE_DEFAULT);
 175
 176         if (dpacl)
 177                 _posix_to_nfsv4_one(dpacl, *acl, flags | NFS4_ACL_TYPE_DEFAULT);
 178
 179  out:
 180         posix_acl_release(pacl);
 181         posix_acl_release(dpacl);
 182         return error;
 183 }
 184
 185 struct posix_acl_summary {
 186         unsigned short owner;
 187         unsigned short users;
 188         unsigned short group;
 189         unsigned short groups;
 190         unsigned short other;
 191         unsigned short mask;
 192 };
 193
 194 static void
 195 summarize_posix_acl(struct posix_acl *acl, struct posix_acl_summary *pas)
 196 {
 197         struct posix_acl_entry *pa, *pe;
 198
 199         /*
 200          * Only pas.users and pas.groups need initialization; previous
 201          * posix_acl_valid() calls ensure that the other fields will be
 202          * initialized in the following loop.  But, just to placate gcc:
 203          */
 204         memset(pas, 0, sizeof(*pas));
 205         pas->mask = 07;
 206
 207         pe = acl->a_entries + acl->a_count;
 208
 209         FOREACH_ACL_ENTRY(pa, acl, pe) {
 210                 switch (pa->e_tag) {
 211                         case ACL_USER_OBJ:
 212                                 pas->owner = pa->e_perm;
 213                                 break;
 214                         case ACL_GROUP_OBJ:
 215                                 pas->group = pa->e_perm;
 216                                 break;
 217                         case ACL_USER:
 218                                 pas->users |= pa->e_perm;
 219                                 break;
 220                         case ACL_GROUP:
 221                                 pas->groups |= pa->e_perm;
 222                                 break;
 223                         case ACL_OTHER:
 224                                 pas->other = pa->e_perm;
 225                                 break;
 226                         case ACL_MASK:
 227                                 pas->mask = pa->e_perm;
 228                                 break;
 229                 }
 230         }
 231         /* We'll only care about effective permissions: */
 232         pas->users &= pas->mask;
 233         pas->group &= pas->mask;
 234         pas->groups &= pas->mask;
 235 }
 236
 237 /* We assume the acl has been verified with posix_acl_valid. */
 238 static void
 239 _posix_to_nfsv4_one(struct posix_acl *pacl, struct nfs4_acl *acl,
 240                                                 unsigned int flags)
 241 {
 242         struct posix_acl_entry *pa, *group_owner_entry;
 243         struct nfs4_ace *ace;
 244         struct posix_acl_summary pas;
 245         unsigned short deny;
 246         int eflag = ((flags & NFS4_ACL_TYPE_DEFAULT) ?
 247                 NFS4_INHERITANCE_FLAGS | NFS4_ACE_INHERIT_ONLY_ACE : 0);
 248
 249         BUG_ON(pacl->a_count < 3);
 250         summarize_posix_acl(pacl, &pas);
 251
 252         pa = pacl->a_entries;
 253         ace = acl->aces + acl->naces;
 254
 255         /* We could deny everything not granted by the owner: */
 256         deny = ~pas.owner;
 257         /*
 258          * but it is equivalent (and simpler) to deny only what is not
 259          * granted by later entries:
 260          */
 261         deny &= pas.users | pas.group | pas.groups | 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_OWNER;
 267                 ace++;
 268                 acl->naces++;
 269         }
 270
 271         ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
 272         ace->flag = eflag;
 273         ace->access_mask = mask_from_posix(pa->e_perm, flags | NFS4_ACL_OWNER);
 274         ace->whotype = NFS4_ACL_WHO_OWNER;
 275         ace++;
 276         acl->naces++;
 277         pa++;
 278
 279         while (pa->e_tag == ACL_USER) {
 280                 deny = ~(pa->e_perm & pas.mask);
 281                 deny &= pas.groups | pas.group | pas.other;
 282                 if (deny) {
 283                         ace->type = NFS4_ACE_ACCESS_DENIED_ACE_TYPE;
 284                         ace->flag = eflag;
 285                         ace->access_mask = deny_mask_from_posix(deny, flags);
 286                         ace->whotype = NFS4_ACL_WHO_NAMED;
 287                         ace->who_uid = pa->e_uid;
 288                         ace++;
 289                         acl->naces++;
 290                 }
 291                 ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
 292                 ace->flag = eflag;
 293                 ace->access_mask = mask_from_posix(pa->e_perm & pas.mask,
 294                                                    flags);
 295                 ace->whotype = NFS4_ACL_WHO_NAMED;
 296                 ace->who_uid = pa->e_uid;
 297                 ace++;
 298                 acl->naces++;
 299                 pa++;
 300         }
 301
 302         /* In the case of groups, we apply allow ACEs first, then deny ACEs,
 303          * since a user can be in more than one group.  */
 304
 305         /* allow ACEs */
 306
 307         group_owner_entry = pa;
 308
 309         ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
 310         ace->flag = eflag;
 311         ace->access_mask = mask_from_posix(pas.group, flags);
 312         ace->whotype = NFS4_ACL_WHO_GROUP;
 313         ace++;
 314         acl->naces++;
 315         pa++;
 316
 317         while (pa->e_tag == ACL_GROUP) {
 318                 ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
 319                 ace->flag = eflag | NFS4_ACE_IDENTIFIER_GROUP;
 320                 ace->access_mask = mask_from_posix(pa->e_perm & pas.mask,
 321                                                    flags);
 322                 ace->whotype = NFS4_ACL_WHO_NAMED;
 323                 ace->who_gid = pa->e_gid;
 324                 ace++;
 325                 acl->naces++;
 326                 pa++;
 327         }
 328
 329         /* deny ACEs */
 330
 331         pa = group_owner_entry;
 332
 333         deny = ~pas.group & pas.other;
 334         if (deny) {
 335                 ace->type = NFS4_ACE_ACCESS_DENIED_ACE_TYPE;
 336                 ace->flag = eflag;
 337                 ace->access_mask = deny_mask_from_posix(deny, flags);
 338                 ace->whotype = NFS4_ACL_WHO_GROUP;
 339                 ace++;
 340                 acl->naces++;
 341         }
 342         pa++;
 343
 344         while (pa->e_tag == ACL_GROUP) {
 345                 deny = ~(pa->e_perm & pas.mask);
 346                 deny &= pas.other;
 347                 if (deny) {
 348                         ace->type = NFS4_ACE_ACCESS_DENIED_ACE_TYPE;
 349                         ace->flag = eflag | NFS4_ACE_IDENTIFIER_GROUP;
 350                         ace->access_mask = deny_mask_from_posix(deny, flags);
 351                         ace->whotype = NFS4_ACL_WHO_NAMED;
 352                         ace->who_gid = pa->e_gid;
 353                         ace++;
 354                         acl->naces++;
 355                 }
 356                 pa++;
 357         }
 358
 359         if (pa->e_tag == ACL_MASK)
 360                 pa++;
 361         ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
 362         ace->flag = eflag;
 363         ace->access_mask = mask_from_posix(pa->e_perm, flags);
 364         ace->whotype = NFS4_ACL_WHO_EVERYONE;
 365         acl->naces++;
 366 }
 367
 368 static bool
 369 pace_gt(struct posix_acl_entry *pace1, struct posix_acl_entry *pace2)
 370 {
 371         if (pace1->e_tag != pace2->e_tag)
 372                 return pace1->e_tag > pace2->e_tag;
 373         if (pace1->e_tag == ACL_USER)
 374                 return uid_gt(pace1->e_uid, pace2->e_uid);
 375         if (pace1->e_tag == ACL_GROUP)
 376                 return gid_gt(pace1->e_gid, pace2->e_gid);
 377         return false;
 378 }
 379
 380 static void
 381 sort_pacl_range(struct posix_acl *pacl, int start, int end) {
 382         int sorted = 0, i;
 383         struct posix_acl_entry tmp;
 384
 385         /* We just do a bubble sort; easy to do in place, and we're not
 386          * expecting acl's to be long enough to justify anything more. */
 387         while (!sorted) {
 388                 sorted = 1;
 389                 for (i = start; i < end; i++) {
 390                         if (pace_gt(&pacl->a_entries[i],
 391                                     &pacl->a_entries[i+1])) {
 392                                 sorted = 0;
 393                                 tmp = pacl->a_entries[i];
 394                                 pacl->a_entries[i] = pacl->a_entries[i+1];
 395                                 pacl->a_entries[i+1] = tmp;
 396                         }
 397                 }
 398         }
 399 }
 400
 401 static void
 402 sort_pacl(struct posix_acl *pacl)
 403 {
 404         /* posix_acl_valid requires that users and groups be in order
 405          * by uid/gid. */
 406         int i, j;
 407
 408         if (pacl->a_count <= 4)
 409                 return; /* no users or groups */
 410         i = 1;
 411         while (pacl->a_entries[i].e_tag == ACL_USER)
 412                 i++;
 413         sort_pacl_range(pacl, 1, i-1);
 414
 415         BUG_ON(pacl->a_entries[i].e_tag != ACL_GROUP_OBJ);
 416         j = ++i;
 417         while (pacl->a_entries[j].e_tag == ACL_GROUP)
 418                 j++;
 419         sort_pacl_range(pacl, i, j-1);
 420         return;
 421 }
 422
 423 /*
 424  * While processing the NFSv4 ACE, this maintains bitmasks representing
 425  * which permission bits have been allowed and which denied to a given
 426  * entity: */
 427 struct posix_ace_state {
 428         u32 allow;
 429         u32 deny;
 430 };
 431
 432 struct posix_user_ace_state {
 433         union {
 434                 kuid_t uid;
 435                 kgid_t gid;
 436         };
 437         struct posix_ace_state perms;
 438 };
 439
 440 struct posix_ace_state_array {
 441         int n;
 442         struct posix_user_ace_state aces[];
 443 };
 444
 445 /*
 446  * While processing the NFSv4 ACE, this maintains the partial permissions
 447  * calculated so far: */
 448
 449 struct posix_acl_state {
 450         int empty;
 451         struct posix_ace_state owner;
 452         struct posix_ace_state group;
 453         struct posix_ace_state other;
 454         struct posix_ace_state everyone;
 455         struct posix_ace_state mask; /* Deny unused in this case */
 456         struct posix_ace_state_array *users;
 457         struct posix_ace_state_array *groups;
 458 };
 459
 460 static int
 461 init_state(struct posix_acl_state *state, int cnt)
 462 {
 463         int alloc;
 464
 465         memset(state, 0, sizeof(struct posix_acl_state));
 466         state->empty = 1;
 467         /*
 468          * In the worst case, each individual acl could be for a distinct
 469          * named user or group, but we don't no which, so we allocate
 470          * enough space for either:
 471          */
 472         alloc = sizeof(struct posix_ace_state_array)
 473                 + cnt*sizeof(struct posix_user_ace_state);
 474         state->users = kzalloc(alloc, GFP_KERNEL);
 475         if (!state->users)
 476                 return -ENOMEM;
 477         state->groups = kzalloc(alloc, GFP_KERNEL);
 478         if (!state->groups) {
 479                 kfree(state->users);
 480                 return -ENOMEM;
 481         }
 482         return 0;
 483 }
 484
 485 static void
 486 free_state(struct posix_acl_state *state) {
 487         kfree(state->users);
 488         kfree(state->groups);
 489 }
 490
 491 static inline void add_to_mask(struct posix_acl_state *state, struct posix_ace_state *astate)
 492 {
 493         state->mask.allow |= astate->allow;
 494 }
 495
 496 /*
 497  * Certain bits (SYNCHRONIZE, DELETE, WRITE_OWNER, READ/WRITE_NAMED_ATTRS,
 498  * READ_ATTRIBUTES, READ_ACL) are currently unenforceable and don't translate
 499  * to traditional read/write/execute permissions.
 500  *
 501  * It's problematic to reject acls that use certain mode bits, because it
 502  * places the burden on users to learn the rules about which bits one
 503  * particular server sets, without giving the user a lot of help--we return an
 504  * error that could mean any number of different things.  To make matters
 505  * worse, the problematic bits might be introduced by some application that's
 506  * automatically mapping from some other acl model.
 507  *
 508  * So wherever possible we accept anything, possibly erring on the side of
 509  * denying more permissions than necessary.
 510  *
 511  * However we do reject *explicit* DENY's of a few bits representing
 512  * permissions we could never deny:
 513  */
 514
 515 static inline int check_deny(u32 mask, int isowner)
 516 {
 517         if (mask & (NFS4_ACE_READ_ATTRIBUTES | NFS4_ACE_READ_ACL))
 518                 return -EINVAL;
 519         if (!isowner)
 520                 return 0;
 521         if (mask & (NFS4_ACE_WRITE_ATTRIBUTES | NFS4_ACE_WRITE_ACL))
 522                 return -EINVAL;
 523         return 0;
 524 }
 525
 526 static struct posix_acl *
 527 posix_state_to_acl(struct posix_acl_state *state, unsigned int flags)
 528 {
 529         struct posix_acl_entry *pace;
 530         struct posix_acl *pacl;
 531         int nace;
 532         int i, error = 0;
 533
 534         /*
 535          * ACLs with no ACEs are treated differently in the inheritable
 536          * and effective cases: when there are no inheritable ACEs, we
 537          * set a zero-length default posix acl:
 538          */
 539         if (state->empty && (flags & NFS4_ACL_TYPE_DEFAULT)) {
 540                 pacl = posix_acl_alloc(0, GFP_KERNEL);
 541                 return pacl ? pacl : ERR_PTR(-ENOMEM);
 542         }
 543         /*
 544          * When there are no effective ACEs, the following will end
 545          * up setting a 3-element effective posix ACL with all
 546          * permissions zero.
 547          */
 548         nace = 4 + state->users->n + state->groups->n;
 549         pacl = posix_acl_alloc(nace, GFP_KERNEL);
 550         if (!pacl)
 551                 return ERR_PTR(-ENOMEM);
 552
 553         pace = pacl->a_entries;
 554         pace->e_tag = ACL_USER_OBJ;
 555         error = check_deny(state->owner.deny, 1);
 556         if (error)
 557                 goto out_err;
 558         low_mode_from_nfs4(state->owner.allow, &pace->e_perm, flags);
 559
 560         for (i=0; i < state->users->n; i++) {
 561                 pace++;
 562                 pace->e_tag = ACL_USER;
 563                 error = check_deny(state->users->aces[i].perms.deny, 0);
 564                 if (error)
 565                         goto out_err;
 566                 low_mode_from_nfs4(state->users->aces[i].perms.allow,
 567                                         &pace->e_perm, flags);
 568                 pace->e_uid = state->users->aces[i].uid;
 569                 add_to_mask(state, &state->users->aces[i].perms);
 570         }
 571
 572         pace++;
 573         pace->e_tag = ACL_GROUP_OBJ;
 574         error = check_deny(state->group.deny, 0);
 575         if (error)
 576                 goto out_err;
 577         low_mode_from_nfs4(state->group.allow, &pace->e_perm, flags);
 578         add_to_mask(state, &state->group);
 579
 580         for (i=0; i < state->groups->n; i++) {
 581                 pace++;
 582                 pace->e_tag = ACL_GROUP;
 583                 error = check_deny(state->groups->aces[i].perms.deny, 0);
 584                 if (error)
 585                         goto out_err;
 586                 low_mode_from_nfs4(state->groups->aces[i].perms.allow,
 587                                         &pace->e_perm, flags);
 588                 pace->e_gid = state->groups->aces[i].gid;
 589                 add_to_mask(state, &state->groups->aces[i].perms);
 590         }
 591
 592         pace++;
 593         pace->e_tag = ACL_MASK;
 594         low_mode_from_nfs4(state->mask.allow, &pace->e_perm, flags);
 595
 596         pace++;
 597         pace->e_tag = ACL_OTHER;
 598         error = check_deny(state->other.deny, 0);
 599         if (error)
 600                 goto out_err;
 601         low_mode_from_nfs4(state->other.allow, &pace->e_perm, flags);
 602
 603         return pacl;
 604 out_err:
 605         posix_acl_release(pacl);
 606         return ERR_PTR(error);
 607 }
 608
 609 static inline void allow_bits(struct posix_ace_state *astate, u32 mask)
 610 {
 611         /* Allow all bits in the mask not already denied: */
 612         astate->allow |= mask & ~astate->deny;
 613 }
 614
 615 static inline void deny_bits(struct posix_ace_state *astate, u32 mask)
 616 {
 617         /* Deny all bits in the mask not already allowed: */
 618         astate->deny |= mask & ~astate->allow;
 619 }
 620
 621 static int find_uid(struct posix_acl_state *state, kuid_t uid)
 622 {
 623         struct posix_ace_state_array *a = state->users;
 624         int i;
 625
 626         for (i = 0; i < a->n; i++)
 627                 if (uid_eq(a->aces[i].uid, uid))
 628                         return i;
 629         /* Not found: */
 630         a->n++;
 631         a->aces[i].uid = uid;
 632         a->aces[i].perms.allow = state->everyone.allow;
 633         a->aces[i].perms.deny  = state->everyone.deny;
 634
 635         return i;
 636 }
 637
 638 static int find_gid(struct posix_acl_state *state, kgid_t gid)
 639 {
 640         struct posix_ace_state_array *a = state->groups;
 641         int i;
 642
 643         for (i = 0; i < a->n; i++)
 644                 if (gid_eq(a->aces[i].gid, gid))
 645                         return i;
 646         /* Not found: */
 647         a->n++;
 648         a->aces[i].gid = gid;
 649         a->aces[i].perms.allow = state->everyone.allow;
 650         a->aces[i].perms.deny  = state->everyone.deny;
 651
 652         return i;
 653 }
 654
 655 static void deny_bits_array(struct posix_ace_state_array *a, u32 mask)
 656 {
 657         int i;
 658
 659         for (i=0; i < a->n; i++)
 660                 deny_bits(&a->aces[i].perms, mask);
 661 }
 662
 663 static void allow_bits_array(struct posix_ace_state_array *a, u32 mask)
 664 {
 665         int i;
 666
 667         for (i=0; i < a->n; i++)
 668                 allow_bits(&a->aces[i].perms, mask);
 669 }
 670
 671 static void process_one_v4_ace(struct posix_acl_state *state,
 672                                 struct nfs4_ace *ace)
 673 {
 674         u32 mask = ace->access_mask;
 675         int i;
 676
 677         state->empty = 0;
 678
 679         switch (ace2type(ace)) {
 680         case ACL_USER_OBJ:
 681                 if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
 682                         allow_bits(&state->owner, mask);
 683                 } else {
 684                         deny_bits(&state->owner, mask);
 685                 }
 686                 break;
 687         case ACL_USER:
 688                 i = find_uid(state, ace->who_uid);
 689                 if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
 690                         allow_bits(&state->users->aces[i].perms, mask);
 691                 } else {
 692                         deny_bits(&state->users->aces[i].perms, mask);
 693                         mask = state->users->aces[i].perms.deny;
 694                         deny_bits(&state->owner, mask);
 695                 }
 696                 break;
 697         case ACL_GROUP_OBJ:
 698                 if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
 699                         allow_bits(&state->group, mask);
 700                 } else {
 701                         deny_bits(&state->group, mask);
 702                         mask = state->group.deny;
 703                         deny_bits(&state->owner, mask);
 704                         deny_bits(&state->everyone, mask);
 705                         deny_bits_array(state->users, mask);
 706                         deny_bits_array(state->groups, mask);
 707                 }
 708                 break;
 709         case ACL_GROUP:
 710                 i = find_gid(state, ace->who_gid);
 711                 if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
 712                         allow_bits(&state->groups->aces[i].perms, mask);
 713                 } else {
 714                         deny_bits(&state->groups->aces[i].perms, mask);
 715                         mask = state->groups->aces[i].perms.deny;
 716                         deny_bits(&state->owner, mask);
 717                         deny_bits(&state->group, mask);
 718                         deny_bits(&state->everyone, mask);
 719                         deny_bits_array(state->users, mask);
 720                         deny_bits_array(state->groups, mask);
 721                 }
 722                 break;
 723         case ACL_OTHER:
 724                 if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
 725                         allow_bits(&state->owner, mask);
 726                         allow_bits(&state->group, mask);
 727                         allow_bits(&state->other, mask);
 728                         allow_bits(&state->everyone, mask);
 729                         allow_bits_array(state->users, mask);
 730                         allow_bits_array(state->groups, mask);
 731                 } else {
 732                         deny_bits(&state->owner, mask);
 733                         deny_bits(&state->group, mask);
 734                         deny_bits(&state->other, mask);
 735                         deny_bits(&state->everyone, mask);
 736                         deny_bits_array(state->users, mask);
 737                         deny_bits_array(state->groups, mask);
 738                 }
 739         }
 740 }
 741
 742 static int nfs4_acl_nfsv4_to_posix(struct nfs4_acl *acl,
 743                 struct posix_acl **pacl, struct posix_acl **dpacl,
 744                 unsigned int flags)
 745 {
 746         struct posix_acl_state effective_acl_state, default_acl_state;
 747         struct nfs4_ace *ace;
 748         int ret;
 749
 750         ret = init_state(&effective_acl_state, acl->naces);
 751         if (ret)
 752                 return ret;
 753         ret = init_state(&default_acl_state, acl->naces);
 754         if (ret)
 755                 goto out_estate;
 756         ret = -EINVAL;
 757         for (ace = acl->aces; ace < acl->aces + acl->naces; ace++) {
 758                 if (ace->type != NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE &&
 759                     ace->type != NFS4_ACE_ACCESS_DENIED_ACE_TYPE)
 760                         goto out_dstate;
 761                 if (ace->flag & ~NFS4_SUPPORTED_FLAGS)
 762                         goto out_dstate;
 763                 if ((ace->flag & NFS4_INHERITANCE_FLAGS) == 0) {
 764                         process_one_v4_ace(&effective_acl_state, ace);
 765                         continue;
 766                 }
 767                 if (!(flags & NFS4_ACL_DIR))
 768                         goto out_dstate;
 769                 /*
 770                  * Note that when only one of FILE_INHERIT or DIRECTORY_INHERIT
 771                  * is set, we're effectively turning on the other.  That's OK,
 772                  * according to rfc 3530.
 773                  */
 774                 process_one_v4_ace(&default_acl_state, ace);
 775
 776                 if (!(ace->flag & NFS4_ACE_INHERIT_ONLY_ACE))
 777                         process_one_v4_ace(&effective_acl_state, ace);
 778         }
 779         *pacl = posix_state_to_acl(&effective_acl_state, flags);
 780         if (IS_ERR(*pacl)) {
 781                 ret = PTR_ERR(*pacl);
 782                 *pacl = NULL;
 783                 goto out_dstate;
 784         }
 785         *dpacl = posix_state_to_acl(&default_acl_state,
 786                                                 flags | NFS4_ACL_TYPE_DEFAULT);
 787         if (IS_ERR(*dpacl)) {
 788                 ret = PTR_ERR(*dpacl);
 789                 *dpacl = NULL;
 790                 posix_acl_release(*pacl);
 791                 *pacl = NULL;
 792                 goto out_dstate;
 793         }
 794         sort_pacl(*pacl);
 795         sort_pacl(*dpacl);
 796         ret = 0;
 797 out_dstate:
 798         free_state(&default_acl_state);
 799 out_estate:
 800         free_state(&effective_acl_state);
 801         return ret;
 802 }
 803
 804 __be32
 805 nfsd4_set_nfs4_acl(struct svc_rqst *rqstp, struct svc_fh *fhp,
 806                 struct nfs4_acl *acl)
 807 {
 808         __be32 error;
 809         int host_error;
 810         struct dentry *dentry;
 811         struct inode *inode;
 812         struct posix_acl *pacl = NULL, *dpacl = NULL;
 813         unsigned int flags = 0;
 814
 815         /* Get inode */
 816         error = fh_verify(rqstp, fhp, 0, NFSD_MAY_SATTR);
 817         if (error)
 818                 return error;
 819
 820         dentry = fhp->fh_dentry;
 821         inode = dentry->d_inode;
 822
 823         if (!inode->i_op->set_acl || !IS_POSIXACL(inode))
 824                 return nfserr_attrnotsupp;
 825
 826         if (S_ISDIR(inode->i_mode))
 827                 flags = NFS4_ACL_DIR;
 828
 829         host_error = nfs4_acl_nfsv4_to_posix(acl, &pacl, &dpacl, flags);
 830         if (host_error == -EINVAL)
 831                 return nfserr_attrnotsupp;
 832         if (host_error < 0)
 833                 goto out_nfserr;
 834
 835         host_error = inode->i_op->set_acl(inode, pacl, ACL_TYPE_ACCESS);
 836         if (host_error < 0)
 837                 goto out_release;
 838
 839         if (S_ISDIR(inode->i_mode)) {
 840                 host_error = inode->i_op->set_acl(inode, dpacl,
 841                                                   ACL_TYPE_DEFAULT);
 842         }
 843
 844 out_release:
 845         posix_acl_release(pacl);
 846         posix_acl_release(dpacl);
 847 out_nfserr:
 848         if (host_error == -EOPNOTSUPP)
 849                 return nfserr_attrnotsupp;
 850         else
 851                 return nfserrno(host_error);
 852 }
 853
 854
 855 static short
 856 ace2type(struct nfs4_ace *ace)
 857 {
 858         switch (ace->whotype) {
 859                 case NFS4_ACL_WHO_NAMED:
 860                         return (ace->flag & NFS4_ACE_IDENTIFIER_GROUP ?
 861                                         ACL_GROUP : ACL_USER);
 862                 case NFS4_ACL_WHO_OWNER:
 863                         return ACL_USER_OBJ;
 864                 case NFS4_ACL_WHO_GROUP:
 865                         return ACL_GROUP_OBJ;
 866                 case NFS4_ACL_WHO_EVERYONE:
 867                         return ACL_OTHER;
 868         }
 869         BUG();
 870         return -1;
 871 }
 872
 873 struct nfs4_acl *
 874 nfs4_acl_new(int n)
 875 {
 876         struct nfs4_acl *acl;
 877
 878         acl = kmalloc(sizeof(*acl) + n*sizeof(struct nfs4_ace), GFP_KERNEL);
 879         if (acl == NULL)
 880                 return NULL;
 881         acl->naces = 0;
 882         return acl;
 883 }
 884
 885 static struct {
 886         char *string;
 887         int   stringlen;
 888         int type;
 889 } s2t_map[] = {
 890         {
 891                 .string    = "OWNER@",
 892                 .stringlen = sizeof("OWNER@") - 1,
 893                 .type      = NFS4_ACL_WHO_OWNER,
 894         },
 895         {
 896                 .string    = "GROUP@",
 897                 .stringlen = sizeof("GROUP@") - 1,
 898                 .type      = NFS4_ACL_WHO_GROUP,
 899         },
 900         {
 901                 .string    = "EVERYONE@",
 902                 .stringlen = sizeof("EVERYONE@") - 1,
 903                 .type      = NFS4_ACL_WHO_EVERYONE,
 904         },
 905 };
 906
 907 int
 908 nfs4_acl_get_whotype(char *p, u32 len)
 909 {
 910         int i;
 911
 912         for (i = 0; i < ARRAY_SIZE(s2t_map); i++) {
 913                 if (s2t_map[i].stringlen == len &&
 914                                 0 == memcmp(s2t_map[i].string, p, len))
 915                         return s2t_map[i].type;
 916         }
 917         return NFS4_ACL_WHO_NAMED;
 918 }
 919
 920 __be32 nfs4_acl_write_who(int who, __be32 **p, int *len)
 921 {
 922         int i;
 923         int bytes;
 924
 925         for (i = 0; i < ARRAY_SIZE(s2t_map); i++) {
 926                 if (s2t_map[i].type != who)
 927                         continue;
 928                 bytes = 4 + (XDR_QUADLEN(s2t_map[i].stringlen) << 2);
 929                 if (bytes > *len)
 930                         return nfserr_resource;
 931                 *p = xdr_encode_opaque(*p, s2t_map[i].string,
 932                                         s2t_map[i].stringlen);
 933                 *len -= bytes;
 934                 return 0;
 935         }
 936         WARN_ON_ONCE(1);
 937         return -1;
 938 }