fs/nfsd/nfs4acl.c

   1 /*
   2  *  fs/nfs4acl/acl.c
   3  *
   4  *  Common NFSv4 ACL handling code.
   5  *
   6  *  Copyright (c) 2002, 2003 The Regents of the University of Michigan.
   7  *  All rights reserved.
   8  *
   9  *  Marius Aamodt Eriksen <marius@umich.edu>
  10  *  Jeff Sedlak <jsedlak@umich.edu>
  11  *  J. Bruce Fields <bfields@umich.edu>
  12  *
  13  *  Redistribution and use in source and binary forms, with or without
  14  *  modification, are permitted provided that the following conditions
  15  *  are met:
  16  *
  17  *  1. Redistributions of source code must retain the above copyright
  18  *     notice, this list of conditions and the following disclaimer.
  19  *  2. Redistributions in binary form must reproduce the above copyright
  20  *     notice, this list of conditions and the following disclaimer in the
  21  *     documentation and/or other materials provided with the distribution.
  22  *  3. Neither the name of the University nor the names of its
  23  *     contributors may be used to endorse or promote products derived
  24  *     from this software without specific prior written permission.
  25  *
  26  *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
  27  *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  28  *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  29  *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  30  *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  31  *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  32  *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
  33  *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  34  *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  35  *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  36  *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  37  */
  38
  39 #include <linux/string.h>
  40 #include <linux/slab.h>
  41 #include <linux/list.h>
  42 #include <linux/types.h>
  43 #include <linux/fs.h>
  44 #include <linux/module.h>
  45 #include <linux/nfs_fs.h>
  46 #include <linux/posix_acl.h>
  47 #include <linux/nfs4.h>
  48 #include <linux/nfs4_acl.h>
  49
  50
  51 /* mode bit translations: */
  52 #define NFS4_READ_MODE (NFS4_ACE_READ_DATA)
  53 #define NFS4_WRITE_MODE (NFS4_ACE_WRITE_DATA | NFS4_ACE_APPEND_DATA)
  54 #define NFS4_EXECUTE_MODE NFS4_ACE_EXECUTE
  55 #define NFS4_ANYONE_MODE (NFS4_ACE_READ_ATTRIBUTES | NFS4_ACE_READ_ACL | NFS4_ACE_SYNCHRONIZE)
  56 #define NFS4_OWNER_MODE (NFS4_ACE_WRITE_ATTRIBUTES | NFS4_ACE_WRITE_ACL)
  57
  58 /* We don't support these bits; insist they be neither allowed nor denied */
  59 #define NFS4_MASK_UNSUPP (NFS4_ACE_DELETE | NFS4_ACE_WRITE_OWNER \
  60                 | NFS4_ACE_READ_NAMED_ATTRS | NFS4_ACE_WRITE_NAMED_ATTRS)
  61
  62 /* flags used to simulate posix default ACLs */
  63 #define NFS4_INHERITANCE_FLAGS (NFS4_ACE_FILE_INHERIT_ACE \
  64                 | NFS4_ACE_DIRECTORY_INHERIT_ACE | NFS4_ACE_INHERIT_ONLY_ACE)
  65
  66 #define MASK_EQUAL(mask1, mask2) \
  67         ( ((mask1) & NFS4_ACE_MASK_ALL) == ((mask2) & NFS4_ACE_MASK_ALL) )
  68
  69 static u32
  70 mask_from_posix(unsigned short perm, unsigned int flags)
  71 {
  72         int mask = NFS4_ANYONE_MODE;
  73
  74         if (flags & NFS4_ACL_OWNER)
  75                 mask |= NFS4_OWNER_MODE;
  76         if (perm & ACL_READ)
  77                 mask |= NFS4_READ_MODE;
  78         if (perm & ACL_WRITE)
  79                 mask |= NFS4_WRITE_MODE;
  80         if ((perm & ACL_WRITE) && (flags & NFS4_ACL_DIR))
  81                 mask |= NFS4_ACE_DELETE_CHILD;
  82         if (perm & ACL_EXECUTE)
  83                 mask |= NFS4_EXECUTE_MODE;
  84         return mask;
  85 }
  86
  87 static u32
  88 deny_mask(u32 allow_mask, unsigned int flags)
  89 {
  90         u32 ret = ~allow_mask & ~NFS4_MASK_UNSUPP;
  91         if (!(flags & NFS4_ACL_DIR))
  92                 ret &= ~NFS4_ACE_DELETE_CHILD;
  93         return ret;
  94 }
  95
  96 /* XXX: modify functions to return NFS errors; they're only ever
  97  * used by nfs code, after all.... */
  98
  99 /* We only map from NFSv4 to POSIX ACLs when setting ACLs, when we err on the
 100  * side of being more restrictive, so the mode bit mapping below is
 101  * pessimistic.  An optimistic version would be needed to handle DENY's,
 102  * but we espect to coalesce all ALLOWs and DENYs before mapping to mode
 103  * bits. */
 104
 105 static void
 106 low_mode_from_nfs4(u32 perm, unsigned short *mode, unsigned int flags)
 107 {
 108         u32 write_mode = NFS4_WRITE_MODE;
 109
 110         if (flags & NFS4_ACL_DIR)
 111                 write_mode |= NFS4_ACE_DELETE_CHILD;
 112         *mode = 0;
 113         if ((perm & NFS4_READ_MODE) == NFS4_READ_MODE)
 114                 *mode |= ACL_READ;
 115         if ((perm & write_mode) == write_mode)
 116                 *mode |= ACL_WRITE;
 117         if ((perm & NFS4_EXECUTE_MODE) == NFS4_EXECUTE_MODE)
 118                 *mode |= ACL_EXECUTE;
 119 }
 120
 121 struct ace_container {
 122         struct nfs4_ace  *ace;
 123         struct list_head  ace_l;
 124 };
 125
 126 static short ace2type(struct nfs4_ace *);
 127 static int _posix_to_nfsv4_one(struct posix_acl *, struct nfs4_acl *, unsigned int);
 128 static struct posix_acl *_nfsv4_to_posix_one(struct nfs4_acl *, unsigned int);
 129 int nfs4_acl_add_ace(struct nfs4_acl *, u32, u32, u32, int, uid_t);
 130 static int nfs4_acl_split(struct nfs4_acl *, struct nfs4_acl *);
 131
 132 struct nfs4_acl *
 133 nfs4_acl_posix_to_nfsv4(struct posix_acl *pacl, struct posix_acl *dpacl,
 134                         unsigned int flags)
 135 {
 136         struct nfs4_acl *acl;
 137         int error = -EINVAL;
 138
 139         if ((pacl != NULL &&
 140                 (posix_acl_valid(pacl) < 0 || pacl->a_count == 0)) ||
 141             (dpacl != NULL &&
 142                 (posix_acl_valid(dpacl) < 0 || dpacl->a_count == 0)))
 143                 goto out_err;
 144
 145         acl = nfs4_acl_new();
 146         if (acl == NULL) {
 147                 error = -ENOMEM;
 148                 goto out_err;
 149         }
 150
 151         if (pacl != NULL) {
 152                 error = _posix_to_nfsv4_one(pacl, acl,
 153                                                 flags & ~NFS4_ACL_TYPE_DEFAULT);
 154                 if (error < 0)
 155                         goto out_acl;
 156         }
 157
 158         if (dpacl != NULL) {
 159                 error = _posix_to_nfsv4_one(dpacl, acl,
 160                                                 flags | NFS4_ACL_TYPE_DEFAULT);
 161                 if (error < 0)
 162                         goto out_acl;
 163         }
 164
 165         return acl;
 166
 167 out_acl:
 168         nfs4_acl_free(acl);
 169 out_err:
 170         acl = ERR_PTR(error);
 171
 172         return acl;
 173 }
 174
 175 static int
 176 nfs4_acl_add_pair(struct nfs4_acl *acl, int eflag, u32 mask, int whotype,
 177                 uid_t owner, unsigned int flags)
 178 {
 179         int error;
 180
 181         error = nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE,
 182                                  eflag, mask, whotype, owner);
 183         if (error < 0)
 184                 return error;
 185         error = nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_DENIED_ACE_TYPE,
 186                                 eflag, deny_mask(mask, flags), whotype, owner);
 187         return error;
 188 }
 189
 190 /* We assume the acl has been verified with posix_acl_valid. */
 191 static int
 192 _posix_to_nfsv4_one(struct posix_acl *pacl, struct nfs4_acl *acl,
 193                                                 unsigned int flags)
 194 {
 195         struct posix_acl_entry *pa, *pe, *group_owner_entry;
 196         int error = -EINVAL;
 197         u32 mask, mask_mask;
 198         int eflag = ((flags & NFS4_ACL_TYPE_DEFAULT) ?
 199                                         NFS4_INHERITANCE_FLAGS : 0);
 200
 201         BUG_ON(pacl->a_count < 3);
 202         pe = pacl->a_entries + pacl->a_count;
 203         pa = pe - 2; /* if mask entry exists, it's second from the last. */
 204         if (pa->e_tag == ACL_MASK)
 205                 mask_mask = deny_mask(mask_from_posix(pa->e_perm, flags), flags);
 206         else
 207                 mask_mask = 0;
 208
 209         pa = pacl->a_entries;
 210         BUG_ON(pa->e_tag != ACL_USER_OBJ);
 211         mask = mask_from_posix(pa->e_perm, flags | NFS4_ACL_OWNER);
 212         error = nfs4_acl_add_pair(acl, eflag, mask, NFS4_ACL_WHO_OWNER, 0, flags);
 213         if (error < 0)
 214                 goto out;
 215         pa++;
 216
 217         while (pa->e_tag == ACL_USER) {
 218                 mask = mask_from_posix(pa->e_perm, flags);
 219                 error = nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_DENIED_ACE_TYPE,
 220                                 eflag,  mask_mask, NFS4_ACL_WHO_NAMED, pa->e_id);
 221                 if (error < 0)
 222                         goto out;
 223
 224
 225                 error = nfs4_acl_add_pair(acl, eflag, mask,
 226                                 NFS4_ACL_WHO_NAMED, pa->e_id, flags);
 227                 if (error < 0)
 228                         goto out;
 229                 pa++;
 230         }
 231
 232         /* In the case of groups, we apply allow ACEs first, then deny ACEs,
 233          * since a user can be in more than one group.  */
 234
 235         /* allow ACEs */
 236
 237         if (pacl->a_count > 3) {
 238                 BUG_ON(pa->e_tag != ACL_GROUP_OBJ);
 239                 error = nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_DENIED_ACE_TYPE,
 240                                 NFS4_ACE_IDENTIFIER_GROUP | eflag, mask_mask,
 241                                 NFS4_ACL_WHO_GROUP, 0);
 242                 if (error < 0)
 243                         goto out;
 244         }
 245         group_owner_entry = pa;
 246         mask = mask_from_posix(pa->e_perm, flags);
 247         error = nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE,
 248                         NFS4_ACE_IDENTIFIER_GROUP | eflag, mask,
 249                         NFS4_ACL_WHO_GROUP, 0);
 250         if (error < 0)
 251                 goto out;
 252         pa++;
 253
 254         while (pa->e_tag == ACL_GROUP) {
 255                 mask = mask_from_posix(pa->e_perm, flags);
 256                 error = nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_DENIED_ACE_TYPE,
 257                                 NFS4_ACE_IDENTIFIER_GROUP | eflag, mask_mask,
 258                                 NFS4_ACL_WHO_NAMED, pa->e_id);
 259                 if (error < 0)
 260                         goto out;
 261
 262                 error = nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE,
 263                                 NFS4_ACE_IDENTIFIER_GROUP | eflag, mask,
 264                                 NFS4_ACL_WHO_NAMED, pa->e_id);
 265                 if (error < 0)
 266                         goto out;
 267                 pa++;
 268         }
 269
 270         /* deny ACEs */
 271
 272         pa = group_owner_entry;
 273         mask = mask_from_posix(pa->e_perm, flags);
 274         error = nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_DENIED_ACE_TYPE,
 275                         NFS4_ACE_IDENTIFIER_GROUP | eflag,
 276                         deny_mask(mask, flags), NFS4_ACL_WHO_GROUP, 0);
 277         if (error < 0)
 278                 goto out;
 279         pa++;
 280         while (pa->e_tag == ACL_GROUP) {
 281                 mask = mask_from_posix(pa->e_perm, flags);
 282                 error = nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_DENIED_ACE_TYPE,
 283                                 NFS4_ACE_IDENTIFIER_GROUP | eflag,
 284                                 deny_mask(mask, flags), NFS4_ACL_WHO_NAMED, pa->e_id);
 285                 if (error < 0)
 286                         goto out;
 287                 pa++;
 288         }
 289
 290         if (pa->e_tag == ACL_MASK)
 291                 pa++;
 292         BUG_ON(pa->e_tag != ACL_OTHER);
 293         mask = mask_from_posix(pa->e_perm, flags);
 294         error = nfs4_acl_add_pair(acl, eflag, mask, NFS4_ACL_WHO_EVERYONE, 0, flags);
 295
 296 out:
 297         return error;
 298 }
 299
 300 static void
 301 sort_pacl_range(struct posix_acl *pacl, int start, int end) {
 302         int sorted = 0, i;
 303         struct posix_acl_entry tmp;
 304
 305         /* We just do a bubble sort; easy to do in place, and we're not
 306          * expecting acl's to be long enough to justify anything more. */
 307         while (!sorted) {
 308                 sorted = 1;
 309                 for (i = start; i < end; i++) {
 310                         if (pacl->a_entries[i].e_id
 311                                         > pacl->a_entries[i+1].e_id) {
 312                                 sorted = 0;
 313                                 tmp = pacl->a_entries[i];
 314                                 pacl->a_entries[i] = pacl->a_entries[i+1];
 315                                 pacl->a_entries[i+1] = tmp;
 316                         }
 317                 }
 318         }
 319 }
 320
 321 static void
 322 sort_pacl(struct posix_acl *pacl)
 323 {
 324         /* posix_acl_valid requires that users and groups be in order
 325          * by uid/gid. */
 326         int i, j;
 327
 328         if (pacl->a_count <= 4)
 329                 return; /* no users or groups */
 330         i = 1;
 331         while (pacl->a_entries[i].e_tag == ACL_USER)
 332                 i++;
 333         sort_pacl_range(pacl, 1, i-1);
 334
 335         BUG_ON(pacl->a_entries[i].e_tag != ACL_GROUP_OBJ);
 336         j = i++;
 337         while (pacl->a_entries[j].e_tag == ACL_GROUP)
 338                 j++;
 339         sort_pacl_range(pacl, i, j-1);
 340         return;
 341 }
 342
 343 int
 344 nfs4_acl_nfsv4_to_posix(struct nfs4_acl *acl, struct posix_acl **pacl,
 345                 struct posix_acl **dpacl, unsigned int flags)
 346 {
 347         struct nfs4_acl *dacl;
 348         int error = -ENOMEM;
 349
 350         *pacl = NULL;
 351         *dpacl = NULL;
 352
 353         dacl = nfs4_acl_new();
 354         if (dacl == NULL)
 355                 goto out;
 356
 357         error = nfs4_acl_split(acl, dacl);
 358         if (error < 0)
 359                 goto out_acl;
 360
 361         if (pacl != NULL) {
 362                 if (acl->naces == 0) {
 363                         error = -ENODATA;
 364                         goto try_dpacl;
 365                 }
 366
 367                 *pacl = _nfsv4_to_posix_one(acl, flags);
 368                 if (IS_ERR(*pacl)) {
 369                         error = PTR_ERR(*pacl);
 370                         *pacl = NULL;
 371                         goto out_acl;
 372                 }
 373         }
 374
 375 try_dpacl:
 376         if (dpacl != NULL) {
 377                 if (dacl->naces == 0) {
 378                         if (pacl == NULL || *pacl == NULL)
 379                                 error = -ENODATA;
 380                         goto out_acl;
 381                 }
 382
 383                 error = 0;
 384                 *dpacl = _nfsv4_to_posix_one(dacl, flags);
 385                 if (IS_ERR(*dpacl)) {
 386                         error = PTR_ERR(*dpacl);
 387                         *dpacl = NULL;
 388                         goto out_acl;
 389                 }
 390         }
 391
 392 out_acl:
 393         if (error && pacl) {
 394                 posix_acl_release(*pacl);
 395                 *pacl = NULL;
 396         }
 397         nfs4_acl_free(dacl);
 398 out:
 399         return error;
 400 }
 401
 402 /*
 403  * While processing the NFSv4 ACE, this maintains bitmasks representing
 404  * which permission bits have been allowed and which denied to a given
 405  * entity: */
 406 struct posix_ace_state {
 407         u32 allow;
 408         u32 deny;
 409 };
 410
 411 struct posix_user_ace_state {
 412         uid_t uid;
 413         struct posix_ace_state perms;
 414 };
 415
 416 struct posix_ace_state_array {
 417         int n;
 418         struct posix_user_ace_state aces[];
 419 };
 420
 421 /*
 422  * While processing the NFSv4 ACE, this maintains the partial permissions
 423  * calculated so far: */
 424
 425 struct posix_acl_state {
 426         struct posix_ace_state owner;
 427         struct posix_ace_state group;
 428         struct posix_ace_state other;
 429         struct posix_ace_state everyone;
 430         struct posix_ace_state mask; /* Deny unused in this case */
 431         struct posix_ace_state_array *users;
 432         struct posix_ace_state_array *groups;
 433 };
 434
 435 static int
 436 init_state(struct posix_acl_state *state, int cnt)
 437 {
 438         int alloc;
 439
 440         memset(state, 0, sizeof(struct posix_acl_state));
 441         /*
 442          * In the worst case, each individual acl could be for a distinct
 443          * named user or group, but we don't no which, so we allocate
 444          * enough space for either:
 445          */
 446         alloc = sizeof(struct posix_ace_state_array)
 447                 + cnt*sizeof(struct posix_ace_state);
 448         state->users = kzalloc(alloc, GFP_KERNEL);
 449         if (!state->users)
 450                 return -ENOMEM;
 451         state->groups = kzalloc(alloc, GFP_KERNEL);
 452         if (!state->groups) {
 453                 kfree(state->users);
 454                 return -ENOMEM;
 455         }
 456         return 0;
 457 }
 458
 459 static void
 460 free_state(struct posix_acl_state *state) {
 461         kfree(state->users);
 462         kfree(state->groups);
 463 }
 464
 465 static inline void add_to_mask(struct posix_acl_state *state, struct posix_ace_state *astate)
 466 {
 467         state->mask.allow |= astate->allow;
 468 }
 469
 470 /*
 471  * Certain bits (SYNCHRONIZE, DELETE, WRITE_OWNER, READ/WRITE_NAMED_ATTRS,
 472  * READ_ATTRIBUTES, READ_ACL) are currently unenforceable and don't translate
 473  * to traditional read/write/execute permissions.
 474  *
 475  * It's problematic to reject acls that use certain mode bits, because it
 476  * places the burden on users to learn the rules about which bits one
 477  * particular server sets, without giving the user a lot of help--we return an
 478  * error that could mean any number of different things.  To make matters
 479  * worse, the problematic bits might be introduced by some application that's
 480  * automatically mapping from some other acl model.
 481  *
 482  * So wherever possible we accept anything, possibly erring on the side of
 483  * denying more permissions than necessary.
 484  *
 485  * However we do reject *explicit* DENY's of a few bits representing
 486  * permissions we could never deny:
 487  */
 488
 489 static inline int check_deny(u32 mask, int isowner)
 490 {
 491         if (mask & (NFS4_ACE_READ_ATTRIBUTES | NFS4_ACE_READ_ACL))
 492                 return -EINVAL;
 493         if (!isowner)
 494                 return 0;
 495         if (mask & (NFS4_ACE_WRITE_ATTRIBUTES | NFS4_ACE_WRITE_ACL))
 496                 return -EINVAL;
 497         return 0;
 498 }
 499
 500 static struct posix_acl *
 501 posix_state_to_acl(struct posix_acl_state *state, unsigned int flags)
 502 {
 503         struct posix_acl_entry *pace;
 504         struct posix_acl *pacl;
 505         int nace;
 506         int i, error = 0;
 507
 508         nace = 4 + state->users->n + state->groups->n;
 509         pacl = posix_acl_alloc(nace, GFP_KERNEL);
 510         if (!pacl)
 511                 return ERR_PTR(-ENOMEM);
 512
 513         pace = pacl->a_entries;
 514         pace->e_tag = ACL_USER_OBJ;
 515         error = check_deny(state->owner.deny, 1);
 516         if (error)
 517                 goto out_err;
 518         low_mode_from_nfs4(state->owner.allow, &pace->e_perm, flags);
 519         pace->e_id = ACL_UNDEFINED_ID;
 520
 521         for (i=0; i < state->users->n; i++) {
 522                 pace++;
 523                 pace->e_tag = ACL_USER;
 524                 error = check_deny(state->users->aces[i].perms.deny, 0);
 525                 if (error)
 526                         goto out_err;
 527                 low_mode_from_nfs4(state->users->aces[i].perms.allow,
 528                                         &pace->e_perm, flags);
 529                 pace->e_id = state->users->aces[i].uid;
 530                 add_to_mask(state, &state->users->aces[i].perms);
 531         }
 532
 533         pace++;
 534         pace->e_tag = ACL_GROUP_OBJ;
 535         error = check_deny(state->group.deny, 0);
 536         if (error)
 537                 goto out_err;
 538         low_mode_from_nfs4(state->group.allow, &pace->e_perm, flags);
 539         pace->e_id = ACL_UNDEFINED_ID;
 540         add_to_mask(state, &state->group);
 541
 542         for (i=0; i < state->groups->n; i++) {
 543                 pace++;
 544                 pace->e_tag = ACL_GROUP;
 545                 error = check_deny(state->groups->aces[i].perms.deny, 0);
 546                 if (error)
 547                         goto out_err;
 548                 low_mode_from_nfs4(state->groups->aces[i].perms.allow,
 549                                         &pace->e_perm, flags);
 550                 pace->e_id = state->groups->aces[i].uid;
 551                 add_to_mask(state, &state->groups->aces[i].perms);
 552         }
 553
 554         pace++;
 555         pace->e_tag = ACL_MASK;
 556         low_mode_from_nfs4(state->mask.allow, &pace->e_perm, flags);
 557         pace->e_id = ACL_UNDEFINED_ID;
 558
 559         pace++;
 560         pace->e_tag = ACL_OTHER;
 561         error = check_deny(state->other.deny, 0);
 562         if (error)
 563                 goto out_err;
 564         low_mode_from_nfs4(state->other.allow, &pace->e_perm, flags);
 565         pace->e_id = ACL_UNDEFINED_ID;
 566
 567         return pacl;
 568 out_err:
 569         posix_acl_release(pacl);
 570         return ERR_PTR(error);
 571 }
 572
 573 static inline void allow_bits(struct posix_ace_state *astate, u32 mask)
 574 {
 575         /* Allow all bits in the mask not already denied: */
 576         astate->allow |= mask & ~astate->deny;
 577 }
 578
 579 static inline void deny_bits(struct posix_ace_state *astate, u32 mask)
 580 {
 581         /* Deny all bits in the mask not already allowed: */
 582         astate->deny |= mask & ~astate->allow;
 583 }
 584
 585 static int find_uid(struct posix_acl_state *state, struct posix_ace_state_array *a, uid_t uid)
 586 {
 587         int i;
 588
 589         for (i = 0; i < a->n; i++)
 590                 if (a->aces[i].uid == uid)
 591                         return i;
 592         /* Not found: */
 593         a->n++;
 594         a->aces[i].uid = uid;
 595         a->aces[i].perms.allow = state->everyone.allow;
 596         a->aces[i].perms.deny  = state->everyone.deny;
 597
 598         return i;
 599 }
 600
 601 static void deny_bits_array(struct posix_ace_state_array *a, u32 mask)
 602 {
 603         int i;
 604
 605         for (i=0; i < a->n; i++)
 606                 deny_bits(&a->aces[i].perms, mask);
 607 }
 608
 609 static void allow_bits_array(struct posix_ace_state_array *a, u32 mask)
 610 {
 611         int i;
 612
 613         for (i=0; i < a->n; i++)
 614                 allow_bits(&a->aces[i].perms, mask);
 615 }
 616
 617 static void process_one_v4_ace(struct posix_acl_state *state,
 618                                 struct nfs4_ace *ace)
 619 {
 620         u32 mask = ace->access_mask;
 621         int i;
 622
 623         switch (ace2type(ace)) {
 624         case ACL_USER_OBJ:
 625                 if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
 626                         allow_bits(&state->owner, mask);
 627                 } else {
 628                         deny_bits(&state->owner, mask);
 629                 }
 630                 break;
 631         case ACL_USER:
 632                 i = find_uid(state, state->users, ace->who);
 633                 if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
 634                         allow_bits(&state->users->aces[i].perms, mask);
 635                 } else {
 636                         deny_bits(&state->users->aces[i].perms, mask);
 637                         mask = state->users->aces[i].perms.deny;
 638                         deny_bits(&state->owner, mask);
 639                 }
 640                 break;
 641         case ACL_GROUP_OBJ:
 642                 if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
 643                         allow_bits(&state->group, mask);
 644                 } else {
 645                         deny_bits(&state->group, mask);
 646                         mask = state->group.deny;
 647                         deny_bits(&state->owner, mask);
 648                         deny_bits(&state->everyone, mask);
 649                         deny_bits_array(state->users, mask);
 650                         deny_bits_array(state->groups, mask);
 651                 }
 652                 break;
 653         case ACL_GROUP:
 654                 i = find_uid(state, state->groups, ace->who);
 655                 if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
 656                         allow_bits(&state->groups->aces[i].perms, mask);
 657                 } else {
 658                         deny_bits(&state->groups->aces[i].perms, mask);
 659                         mask = state->groups->aces[i].perms.deny;
 660                         deny_bits(&state->owner, mask);
 661                         deny_bits(&state->group, mask);
 662                         deny_bits(&state->everyone, mask);
 663                         deny_bits_array(state->users, mask);
 664                         deny_bits_array(state->groups, mask);
 665                 }
 666                 break;
 667         case ACL_OTHER:
 668                 if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
 669                         allow_bits(&state->owner, mask);
 670                         allow_bits(&state->group, mask);
 671                         allow_bits(&state->other, mask);
 672                         allow_bits(&state->everyone, mask);
 673                         allow_bits_array(state->users, mask);
 674                         allow_bits_array(state->groups, mask);
 675                 } else {
 676                         deny_bits(&state->owner, mask);
 677                         deny_bits(&state->group, mask);
 678                         deny_bits(&state->other, mask);
 679                         deny_bits(&state->everyone, mask);
 680                         deny_bits_array(state->users, mask);
 681                         deny_bits_array(state->groups, mask);
 682                 }
 683         }
 684 }
 685
 686 static struct posix_acl *
 687 _nfsv4_to_posix_one(struct nfs4_acl *n4acl, unsigned int flags)
 688 {
 689         struct posix_acl_state state;
 690         struct posix_acl *pacl;
 691         struct nfs4_ace *ace;
 692         int ret;
 693
 694         ret = init_state(&state, n4acl->naces);
 695         if (ret)
 696                 return ERR_PTR(ret);
 697
 698         list_for_each_entry(ace, &n4acl->ace_head, l_ace)
 699                 process_one_v4_ace(&state, ace);
 700
 701         pacl = posix_state_to_acl(&state, flags);
 702
 703         free_state(&state);
 704
 705         if (!IS_ERR(pacl))
 706                 sort_pacl(pacl);
 707         return pacl;
 708 }
 709
 710 static int
 711 nfs4_acl_split(struct nfs4_acl *acl, struct nfs4_acl *dacl)
 712 {
 713         struct list_head *h, *n;
 714         struct nfs4_ace *ace;
 715         int error = 0;
 716
 717         list_for_each_safe(h, n, &acl->ace_head) {
 718                 ace = list_entry(h, struct nfs4_ace, l_ace);
 719
 720                 if (ace->type != NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE &&
 721                     ace->type != NFS4_ACE_ACCESS_DENIED_ACE_TYPE)
 722                         return -EINVAL;
 723
 724                 if ((ace->flag & NFS4_INHERITANCE_FLAGS)
 725                                 != NFS4_INHERITANCE_FLAGS)
 726                         continue;
 727
 728                 error = nfs4_acl_add_ace(dacl, ace->type, ace->flag,
 729                                 ace->access_mask, ace->whotype, ace->who);
 730                 if (error < 0)
 731                         goto out;
 732
 733                 list_del(h);
 734                 kfree(ace);
 735                 acl->naces--;
 736         }
 737
 738 out:
 739         return error;
 740 }
 741
 742 static short
 743 ace2type(struct nfs4_ace *ace)
 744 {
 745         switch (ace->whotype) {
 746                 case NFS4_ACL_WHO_NAMED:
 747                         return (ace->flag & NFS4_ACE_IDENTIFIER_GROUP ?
 748                                         ACL_GROUP : ACL_USER);
 749                 case NFS4_ACL_WHO_OWNER:
 750                         return ACL_USER_OBJ;
 751                 case NFS4_ACL_WHO_GROUP:
 752                         return ACL_GROUP_OBJ;
 753                 case NFS4_ACL_WHO_EVERYONE:
 754                         return ACL_OTHER;
 755         }
 756         BUG();
 757         return -1;
 758 }
 759
 760 EXPORT_SYMBOL(nfs4_acl_posix_to_nfsv4);
 761 EXPORT_SYMBOL(nfs4_acl_nfsv4_to_posix);
 762
 763 struct nfs4_acl *
 764 nfs4_acl_new(void)
 765 {
 766         struct nfs4_acl *acl;
 767
 768         if ((acl = kmalloc(sizeof(*acl), GFP_KERNEL)) == NULL)
 769                 return NULL;
 770
 771         acl->naces = 0;
 772         INIT_LIST_HEAD(&acl->ace_head);
 773
 774         return acl;
 775 }
 776
 777 void
 778 nfs4_acl_free(struct nfs4_acl *acl)
 779 {
 780         struct list_head *h;
 781         struct nfs4_ace *ace;
 782
 783         if (!acl)
 784                 return;
 785
 786         while (!list_empty(&acl->ace_head)) {
 787                 h = acl->ace_head.next;
 788                 list_del(h);
 789                 ace = list_entry(h, struct nfs4_ace, l_ace);
 790                 kfree(ace);
 791         }
 792
 793         kfree(acl);
 794
 795         return;
 796 }
 797
 798 int
 799 nfs4_acl_add_ace(struct nfs4_acl *acl, u32 type, u32 flag, u32 access_mask,
 800                 int whotype, uid_t who)
 801 {
 802         struct nfs4_ace *ace;
 803
 804         if ((ace = kmalloc(sizeof(*ace), GFP_KERNEL)) == NULL)
 805                 return -ENOMEM;
 806
 807         ace->type = type;
 808         ace->flag = flag;
 809         ace->access_mask = access_mask;
 810         ace->whotype = whotype;
 811         ace->who = who;
 812
 813         list_add_tail(&ace->l_ace, &acl->ace_head);
 814         acl->naces++;
 815
 816         return 0;
 817 }
 818
 819 static struct {
 820         char *string;
 821         int   stringlen;
 822         int type;
 823 } s2t_map[] = {
 824         {
 825                 .string    = "OWNER@",
 826                 .stringlen = sizeof("OWNER@") - 1,
 827                 .type      = NFS4_ACL_WHO_OWNER,
 828         },
 829         {
 830                 .string    = "GROUP@",
 831                 .stringlen = sizeof("GROUP@") - 1,
 832                 .type      = NFS4_ACL_WHO_GROUP,
 833         },
 834         {
 835                 .string    = "EVERYONE@",
 836                 .stringlen = sizeof("EVERYONE@") - 1,
 837                 .type      = NFS4_ACL_WHO_EVERYONE,
 838         },
 839 };
 840
 841 int
 842 nfs4_acl_get_whotype(char *p, u32 len)
 843 {
 844         int i;
 845
 846         for (i = 0; i < ARRAY_SIZE(s2t_map); i++) {
 847                 if (s2t_map[i].stringlen == len &&
 848                                 0 == memcmp(s2t_map[i].string, p, len))
 849                         return s2t_map[i].type;
 850         }
 851         return NFS4_ACL_WHO_NAMED;
 852 }
 853
 854 int
 855 nfs4_acl_write_who(int who, char *p)
 856 {
 857         int i;
 858
 859         for (i = 0; i < ARRAY_SIZE(s2t_map); i++) {
 860                 if (s2t_map[i].type == who) {
 861                         memcpy(p, s2t_map[i].string, s2t_map[i].stringlen);
 862                         return s2t_map[i].stringlen;
 863                 }
 864         }
 865         BUG();
 866         return -1;
 867 }
 868
 869 EXPORT_SYMBOL(nfs4_acl_new);
 870 EXPORT_SYMBOL(nfs4_acl_free);
 871 EXPORT_SYMBOL(nfs4_acl_add_ace);
 872 EXPORT_SYMBOL(nfs4_acl_get_whotype);
 873 EXPORT_SYMBOL(nfs4_acl_write_who);