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 "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
  65 static u32
  66 mask_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
  83 static u32
  84 deny_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
 108 static void
 109 low_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
 124 struct ace_container {
 125         struct nfs4_ace  *ace;
 126         struct list_head  ace_l;
 127 };
 128
 129 static short ace2type(struct nfs4_ace *);
 130 static void _posix_to_nfsv4_one(struct posix_acl *, struct nfs4_acl *,
 131                                 unsigned int);
 132
 133 struct nfs4_acl *
 134 nfs4_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
 165 struct 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
 174 static void
 175 summarize_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. */
 218 static 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_uid = pa->e_uid;
 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_uid = pa->e_uid;
 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_gid = pa->e_gid;
 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_gid = pa->e_gid;
 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
 348 static bool
 349 pace_gt(struct posix_acl_entry *pace1, struct posix_acl_entry *pace2)
 350 {
 351         if (pace1->e_tag != pace2->e_tag)
 352                 return pace1->e_tag > pace2->e_tag;
 353         if (pace1->e_tag == ACL_USER)
 354                 return uid_gt(pace1->e_uid, pace2->e_uid);
 355         if (pace1->e_tag == ACL_GROUP)
 356                 return gid_gt(pace1->e_gid, pace2->e_gid);
 357         return false;
 358 }
 359
 360 static void
 361 sort_pacl_range(struct posix_acl *pacl, int start, int end) {
 362         int sorted = 0, i;
 363         struct posix_acl_entry tmp;
 364
 365         /* We just do a bubble sort; easy to do in place, and we're not
 366          * expecting acl's to be long enough to justify anything more. */
 367         while (!sorted) {
 368                 sorted = 1;
 369                 for (i = start; i < end; i++) {
 370                         if (pace_gt(&pacl->a_entries[i],
 371                                     &pacl->a_entries[i+1])) {
 372                                 sorted = 0;
 373                                 tmp = pacl->a_entries[i];
 374                                 pacl->a_entries[i] = pacl->a_entries[i+1];
 375                                 pacl->a_entries[i+1] = tmp;
 376                         }
 377                 }
 378         }
 379 }
 380
 381 static void
 382 sort_pacl(struct posix_acl *pacl)
 383 {
 384         /* posix_acl_valid requires that users and groups be in order
 385          * by uid/gid. */
 386         int i, j;
 387
 388         if (pacl->a_count <= 4)
 389                 return; /* no users or groups */
 390         i = 1;
 391         while (pacl->a_entries[i].e_tag == ACL_USER)
 392                 i++;
 393         sort_pacl_range(pacl, 1, i-1);
 394
 395         BUG_ON(pacl->a_entries[i].e_tag != ACL_GROUP_OBJ);
 396         j = ++i;
 397         while (pacl->a_entries[j].e_tag == ACL_GROUP)
 398                 j++;
 399         sort_pacl_range(pacl, i, j-1);
 400         return;
 401 }
 402
 403 /*
 404  * While processing the NFSv4 ACE, this maintains bitmasks representing
 405  * which permission bits have been allowed and which denied to a given
 406  * entity: */
 407 struct posix_ace_state {
 408         u32 allow;
 409         u32 deny;
 410 };
 411
 412 struct posix_user_ace_state {
 413         union {
 414                 kuid_t uid;
 415                 kgid_t gid;
 416         };
 417         struct posix_ace_state perms;
 418 };
 419
 420 struct posix_ace_state_array {
 421         int n;
 422         struct posix_user_ace_state aces[];
 423 };
 424
 425 /*
 426  * While processing the NFSv4 ACE, this maintains the partial permissions
 427  * calculated so far: */
 428
 429 struct posix_acl_state {
 430         int empty;
 431         struct posix_ace_state owner;
 432         struct posix_ace_state group;
 433         struct posix_ace_state other;
 434         struct posix_ace_state everyone;
 435         struct posix_ace_state mask; /* Deny unused in this case */
 436         struct posix_ace_state_array *users;
 437         struct posix_ace_state_array *groups;
 438 };
 439
 440 static int
 441 init_state(struct posix_acl_state *state, int cnt)
 442 {
 443         int alloc;
 444
 445         memset(state, 0, sizeof(struct posix_acl_state));
 446         state->empty = 1;
 447         /*
 448          * In the worst case, each individual acl could be for a distinct
 449          * named user or group, but we don't no which, so we allocate
 450          * enough space for either:
 451          */
 452         alloc = sizeof(struct posix_ace_state_array)
 453                 + cnt*sizeof(struct posix_user_ace_state);
 454         state->users = kzalloc(alloc, GFP_KERNEL);
 455         if (!state->users)
 456                 return -ENOMEM;
 457         state->groups = kzalloc(alloc, GFP_KERNEL);
 458         if (!state->groups) {
 459                 kfree(state->users);
 460                 return -ENOMEM;
 461         }
 462         return 0;
 463 }
 464
 465 static void
 466 free_state(struct posix_acl_state *state) {
 467         kfree(state->users);
 468         kfree(state->groups);
 469 }
 470
 471 static inline void add_to_mask(struct posix_acl_state *state, struct posix_ace_state *astate)
 472 {
 473         state->mask.allow |= astate->allow;
 474 }
 475
 476 /*
 477  * Certain bits (SYNCHRONIZE, DELETE, WRITE_OWNER, READ/WRITE_NAMED_ATTRS,
 478  * READ_ATTRIBUTES, READ_ACL) are currently unenforceable and don't translate
 479  * to traditional read/write/execute permissions.
 480  *
 481  * It's problematic to reject acls that use certain mode bits, because it
 482  * places the burden on users to learn the rules about which bits one
 483  * particular server sets, without giving the user a lot of help--we return an
 484  * error that could mean any number of different things.  To make matters
 485  * worse, the problematic bits might be introduced by some application that's
 486  * automatically mapping from some other acl model.
 487  *
 488  * So wherever possible we accept anything, possibly erring on the side of
 489  * denying more permissions than necessary.
 490  *
 491  * However we do reject *explicit* DENY's of a few bits representing
 492  * permissions we could never deny:
 493  */
 494
 495 static inline int check_deny(u32 mask, int isowner)
 496 {
 497         if (mask & (NFS4_ACE_READ_ATTRIBUTES | NFS4_ACE_READ_ACL))
 498                 return -EINVAL;
 499         if (!isowner)
 500                 return 0;
 501         if (mask & (NFS4_ACE_WRITE_ATTRIBUTES | NFS4_ACE_WRITE_ACL))
 502                 return -EINVAL;
 503         return 0;
 504 }
 505
 506 static struct posix_acl *
 507 posix_state_to_acl(struct posix_acl_state *state, unsigned int flags)
 508 {
 509         struct posix_acl_entry *pace;
 510         struct posix_acl *pacl;
 511         int nace;
 512         int i, error = 0;
 513
 514         /*
 515          * ACLs with no ACEs are treated differently in the inheritable
 516          * and effective cases: when there are no inheritable ACEs, we
 517          * set a zero-length default posix acl:
 518          */
 519         if (state->empty && (flags & NFS4_ACL_TYPE_DEFAULT)) {
 520                 pacl = posix_acl_alloc(0, GFP_KERNEL);
 521                 return pacl ? pacl : ERR_PTR(-ENOMEM);
 522         }
 523         /*
 524          * When there are no effective ACEs, the following will end
 525          * up setting a 3-element effective posix ACL with all
 526          * permissions zero.
 527          */
 528         nace = 4 + state->users->n + state->groups->n;
 529         pacl = posix_acl_alloc(nace, GFP_KERNEL);
 530         if (!pacl)
 531                 return ERR_PTR(-ENOMEM);
 532
 533         pace = pacl->a_entries;
 534         pace->e_tag = ACL_USER_OBJ;
 535         error = check_deny(state->owner.deny, 1);
 536         if (error)
 537                 goto out_err;
 538         low_mode_from_nfs4(state->owner.allow, &pace->e_perm, flags);
 539
 540         for (i=0; i < state->users->n; i++) {
 541                 pace++;
 542                 pace->e_tag = ACL_USER;
 543                 error = check_deny(state->users->aces[i].perms.deny, 0);
 544                 if (error)
 545                         goto out_err;
 546                 low_mode_from_nfs4(state->users->aces[i].perms.allow,
 547                                         &pace->e_perm, flags);
 548                 pace->e_uid = state->users->aces[i].uid;
 549                 add_to_mask(state, &state->users->aces[i].perms);
 550         }
 551
 552         pace++;
 553         pace->e_tag = ACL_GROUP_OBJ;
 554         error = check_deny(state->group.deny, 0);
 555         if (error)
 556                 goto out_err;
 557         low_mode_from_nfs4(state->group.allow, &pace->e_perm, flags);
 558         add_to_mask(state, &state->group);
 559
 560         for (i=0; i < state->groups->n; i++) {
 561                 pace++;
 562                 pace->e_tag = ACL_GROUP;
 563                 error = check_deny(state->groups->aces[i].perms.deny, 0);
 564                 if (error)
 565                         goto out_err;
 566                 low_mode_from_nfs4(state->groups->aces[i].perms.allow,
 567                                         &pace->e_perm, flags);
 568                 pace->e_gid = state->groups->aces[i].gid;
 569                 add_to_mask(state, &state->groups->aces[i].perms);
 570         }
 571
 572         pace++;
 573         pace->e_tag = ACL_MASK;
 574         low_mode_from_nfs4(state->mask.allow, &pace->e_perm, flags);
 575
 576         pace++;
 577         pace->e_tag = ACL_OTHER;
 578         error = check_deny(state->other.deny, 0);
 579         if (error)
 580                 goto out_err;
 581         low_mode_from_nfs4(state->other.allow, &pace->e_perm, flags);
 582
 583         return pacl;
 584 out_err:
 585         posix_acl_release(pacl);
 586         return ERR_PTR(error);
 587 }
 588
 589 static inline void allow_bits(struct posix_ace_state *astate, u32 mask)
 590 {
 591         /* Allow all bits in the mask not already denied: */
 592         astate->allow |= mask & ~astate->deny;
 593 }
 594
 595 static inline void deny_bits(struct posix_ace_state *astate, u32 mask)
 596 {
 597         /* Deny all bits in the mask not already allowed: */
 598         astate->deny |= mask & ~astate->allow;
 599 }
 600
 601 static int find_uid(struct posix_acl_state *state, kuid_t uid)
 602 {
 603         struct posix_ace_state_array *a = state->users;
 604         int i;
 605
 606         for (i = 0; i < a->n; i++)
 607                 if (uid_eq(a->aces[i].uid, uid))
 608                         return i;
 609         /* Not found: */
 610         a->n++;
 611         a->aces[i].uid = uid;
 612         a->aces[i].perms.allow = state->everyone.allow;
 613         a->aces[i].perms.deny  = state->everyone.deny;
 614
 615         return i;
 616 }
 617
 618 static int find_gid(struct posix_acl_state *state, kgid_t gid)
 619 {
 620         struct posix_ace_state_array *a = state->groups;
 621         int i;
 622
 623         for (i = 0; i < a->n; i++)
 624                 if (gid_eq(a->aces[i].gid, gid))
 625                         return i;
 626         /* Not found: */
 627         a->n++;
 628         a->aces[i].gid = gid;
 629         a->aces[i].perms.allow = state->everyone.allow;
 630         a->aces[i].perms.deny  = state->everyone.deny;
 631
 632         return i;
 633 }
 634
 635 static void deny_bits_array(struct posix_ace_state_array *a, u32 mask)
 636 {
 637         int i;
 638
 639         for (i=0; i < a->n; i++)
 640                 deny_bits(&a->aces[i].perms, mask);
 641 }
 642
 643 static void allow_bits_array(struct posix_ace_state_array *a, u32 mask)
 644 {
 645         int i;
 646
 647         for (i=0; i < a->n; i++)
 648                 allow_bits(&a->aces[i].perms, mask);
 649 }
 650
 651 static void process_one_v4_ace(struct posix_acl_state *state,
 652                                 struct nfs4_ace *ace)
 653 {
 654         u32 mask = ace->access_mask;
 655         int i;
 656
 657         state->empty = 0;
 658
 659         switch (ace2type(ace)) {
 660         case ACL_USER_OBJ:
 661                 if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
 662                         allow_bits(&state->owner, mask);
 663                 } else {
 664                         deny_bits(&state->owner, mask);
 665                 }
 666                 break;
 667         case ACL_USER:
 668                 i = find_uid(state, ace->who_uid);
 669                 if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
 670                         allow_bits(&state->users->aces[i].perms, mask);
 671                 } else {
 672                         deny_bits(&state->users->aces[i].perms, mask);
 673                         mask = state->users->aces[i].perms.deny;
 674                         deny_bits(&state->owner, mask);
 675                 }
 676                 break;
 677         case ACL_GROUP_OBJ:
 678                 if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
 679                         allow_bits(&state->group, mask);
 680                 } else {
 681                         deny_bits(&state->group, mask);
 682                         mask = state->group.deny;
 683                         deny_bits(&state->owner, mask);
 684                         deny_bits(&state->everyone, mask);
 685                         deny_bits_array(state->users, mask);
 686                         deny_bits_array(state->groups, mask);
 687                 }
 688                 break;
 689         case ACL_GROUP:
 690                 i = find_gid(state, ace->who_gid);
 691                 if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
 692                         allow_bits(&state->groups->aces[i].perms, mask);
 693                 } else {
 694                         deny_bits(&state->groups->aces[i].perms, mask);
 695                         mask = state->groups->aces[i].perms.deny;
 696                         deny_bits(&state->owner, mask);
 697                         deny_bits(&state->group, mask);
 698                         deny_bits(&state->everyone, mask);
 699                         deny_bits_array(state->users, mask);
 700                         deny_bits_array(state->groups, mask);
 701                 }
 702                 break;
 703         case ACL_OTHER:
 704                 if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
 705                         allow_bits(&state->owner, mask);
 706                         allow_bits(&state->group, mask);
 707                         allow_bits(&state->other, mask);
 708                         allow_bits(&state->everyone, mask);
 709                         allow_bits_array(state->users, mask);
 710                         allow_bits_array(state->groups, mask);
 711                 } else {
 712                         deny_bits(&state->owner, mask);
 713                         deny_bits(&state->group, mask);
 714                         deny_bits(&state->other, mask);
 715                         deny_bits(&state->everyone, mask);
 716                         deny_bits_array(state->users, mask);
 717                         deny_bits_array(state->groups, mask);
 718                 }
 719         }
 720 }
 721
 722 int nfs4_acl_nfsv4_to_posix(struct nfs4_acl *acl, struct posix_acl **pacl,
 723                             struct posix_acl **dpacl, unsigned int flags)
 724 {
 725         struct posix_acl_state effective_acl_state, default_acl_state;
 726         struct nfs4_ace *ace;
 727         int ret;
 728
 729         ret = init_state(&effective_acl_state, acl->naces);
 730         if (ret)
 731                 return ret;
 732         ret = init_state(&default_acl_state, acl->naces);
 733         if (ret)
 734                 goto out_estate;
 735         ret = -EINVAL;
 736         for (ace = acl->aces; ace < acl->aces + acl->naces; ace++) {
 737                 if (ace->type != NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE &&
 738                     ace->type != NFS4_ACE_ACCESS_DENIED_ACE_TYPE)
 739                         goto out_dstate;
 740                 if (ace->flag & ~NFS4_SUPPORTED_FLAGS)
 741                         goto out_dstate;
 742                 if ((ace->flag & NFS4_INHERITANCE_FLAGS) == 0) {
 743                         process_one_v4_ace(&effective_acl_state, ace);
 744                         continue;
 745                 }
 746                 if (!(flags & NFS4_ACL_DIR))
 747                         goto out_dstate;
 748                 /*
 749                  * Note that when only one of FILE_INHERIT or DIRECTORY_INHERIT
 750                  * is set, we're effectively turning on the other.  That's OK,
 751                  * according to rfc 3530.
 752                  */
 753                 process_one_v4_ace(&default_acl_state, ace);
 754
 755                 if (!(ace->flag & NFS4_ACE_INHERIT_ONLY_ACE))
 756                         process_one_v4_ace(&effective_acl_state, ace);
 757         }
 758         *pacl = posix_state_to_acl(&effective_acl_state, flags);
 759         if (IS_ERR(*pacl)) {
 760                 ret = PTR_ERR(*pacl);
 761                 *pacl = NULL;
 762                 goto out_dstate;
 763         }
 764         *dpacl = posix_state_to_acl(&default_acl_state,
 765                                                 flags | NFS4_ACL_TYPE_DEFAULT);
 766         if (IS_ERR(*dpacl)) {
 767                 ret = PTR_ERR(*dpacl);
 768                 *dpacl = NULL;
 769                 posix_acl_release(*pacl);
 770                 *pacl = NULL;
 771                 goto out_dstate;
 772         }
 773         sort_pacl(*pacl);
 774         sort_pacl(*dpacl);
 775         ret = 0;
 776 out_dstate:
 777         free_state(&default_acl_state);
 778 out_estate:
 779         free_state(&effective_acl_state);
 780         return ret;
 781 }
 782
 783 static short
 784 ace2type(struct nfs4_ace *ace)
 785 {
 786         switch (ace->whotype) {
 787                 case NFS4_ACL_WHO_NAMED:
 788                         return (ace->flag & NFS4_ACE_IDENTIFIER_GROUP ?
 789                                         ACL_GROUP : ACL_USER);
 790                 case NFS4_ACL_WHO_OWNER:
 791                         return ACL_USER_OBJ;
 792                 case NFS4_ACL_WHO_GROUP:
 793                         return ACL_GROUP_OBJ;
 794                 case NFS4_ACL_WHO_EVERYONE:
 795                         return ACL_OTHER;
 796         }
 797         BUG();
 798         return -1;
 799 }
 800
 801 EXPORT_SYMBOL(nfs4_acl_posix_to_nfsv4);
 802 EXPORT_SYMBOL(nfs4_acl_nfsv4_to_posix);
 803
 804 struct nfs4_acl *
 805 nfs4_acl_new(int n)
 806 {
 807         struct nfs4_acl *acl;
 808
 809         acl = kmalloc(sizeof(*acl) + n*sizeof(struct nfs4_ace), GFP_KERNEL);
 810         if (acl == NULL)
 811                 return NULL;
 812         acl->naces = 0;
 813         return acl;
 814 }
 815
 816 static struct {
 817         char *string;
 818         int   stringlen;
 819         int type;
 820 } s2t_map[] = {
 821         {
 822                 .string    = "OWNER@",
 823                 .stringlen = sizeof("OWNER@") - 1,
 824                 .type      = NFS4_ACL_WHO_OWNER,
 825         },
 826         {
 827                 .string    = "GROUP@",
 828                 .stringlen = sizeof("GROUP@") - 1,
 829                 .type      = NFS4_ACL_WHO_GROUP,
 830         },
 831         {
 832                 .string    = "EVERYONE@",
 833                 .stringlen = sizeof("EVERYONE@") - 1,
 834                 .type      = NFS4_ACL_WHO_EVERYONE,
 835         },
 836 };
 837
 838 int
 839 nfs4_acl_get_whotype(char *p, u32 len)
 840 {
 841         int i;
 842
 843         for (i = 0; i < ARRAY_SIZE(s2t_map); i++) {
 844                 if (s2t_map[i].stringlen == len &&
 845                                 0 == memcmp(s2t_map[i].string, p, len))
 846                         return s2t_map[i].type;
 847         }
 848         return NFS4_ACL_WHO_NAMED;
 849 }
 850
 851 int
 852 nfs4_acl_write_who(int who, char *p)
 853 {
 854         int i;
 855
 856         for (i = 0; i < ARRAY_SIZE(s2t_map); i++) {
 857                 if (s2t_map[i].type == who) {
 858                         memcpy(p, s2t_map[i].string, s2t_map[i].stringlen);
 859                         return s2t_map[i].stringlen;
 860                 }
 861         }
 862         BUG();
 863         return -1;
 864 }
 865
 866 EXPORT_SYMBOL(nfs4_acl_new);
 867 EXPORT_SYMBOL(nfs4_acl_get_whotype);
 868 EXPORT_SYMBOL(nfs4_acl_write_who);