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 static int
 100 mode_from_nfs4(u32 perm, unsigned short *mode, unsigned int flags)
 101 {
 102         u32 ignore = 0;
 103
 104         if (!(flags & NFS4_ACL_DIR))
 105                 ignore |= NFS4_ACE_DELETE_CHILD; /* ignore it */
 106         perm |= ignore;
 107         *mode = 0;
 108         if ((perm & NFS4_READ_MODE) == NFS4_READ_MODE)
 109                 *mode |= ACL_READ;
 110         if ((perm & NFS4_WRITE_MODE) == NFS4_WRITE_MODE)
 111                 *mode |= ACL_WRITE;
 112         if ((perm & NFS4_EXECUTE_MODE) == NFS4_EXECUTE_MODE)
 113                 *mode |= ACL_EXECUTE;
 114         if (!MASK_EQUAL(perm, ignore|mask_from_posix(*mode, flags)))
 115                 return -EINVAL;
 116         return 0;
 117 }
 118
 119 struct ace_container {
 120         struct nfs4_ace  *ace;
 121         struct list_head  ace_l;
 122 };
 123
 124 static short ace2type(struct nfs4_ace *);
 125 static int _posix_to_nfsv4_one(struct posix_acl *, struct nfs4_acl *, unsigned int);
 126 static struct posix_acl *_nfsv4_to_posix_one(struct nfs4_acl *, unsigned int);
 127 int nfs4_acl_add_ace(struct nfs4_acl *, u32, u32, u32, int, uid_t);
 128 static int nfs4_acl_split(struct nfs4_acl *, struct nfs4_acl *);
 129
 130 struct nfs4_acl *
 131 nfs4_acl_posix_to_nfsv4(struct posix_acl *pacl, struct posix_acl *dpacl,
 132                         unsigned int flags)
 133 {
 134         struct nfs4_acl *acl;
 135         int error = -EINVAL;
 136
 137         if ((pacl != NULL &&
 138                 (posix_acl_valid(pacl) < 0 || pacl->a_count == 0)) ||
 139             (dpacl != NULL &&
 140                 (posix_acl_valid(dpacl) < 0 || dpacl->a_count == 0)))
 141                 goto out_err;
 142
 143         acl = nfs4_acl_new();
 144         if (acl == NULL) {
 145                 error = -ENOMEM;
 146                 goto out_err;
 147         }
 148
 149         if (pacl != NULL) {
 150                 error = _posix_to_nfsv4_one(pacl, acl,
 151                                                 flags & ~NFS4_ACL_TYPE_DEFAULT);
 152                 if (error < 0)
 153                         goto out_acl;
 154         }
 155
 156         if (dpacl != NULL) {
 157                 error = _posix_to_nfsv4_one(dpacl, acl,
 158                                                 flags | NFS4_ACL_TYPE_DEFAULT);
 159                 if (error < 0)
 160                         goto out_acl;
 161         }
 162
 163         return acl;
 164
 165 out_acl:
 166         nfs4_acl_free(acl);
 167 out_err:
 168         acl = ERR_PTR(error);
 169
 170         return acl;
 171 }
 172
 173 static int
 174 nfs4_acl_add_pair(struct nfs4_acl *acl, int eflag, u32 mask, int whotype,
 175                 uid_t owner, unsigned int flags)
 176 {
 177         int error;
 178
 179         error = nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE,
 180                                  eflag, mask, whotype, owner);
 181         if (error < 0)
 182                 return error;
 183         error = nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_DENIED_ACE_TYPE,
 184                                 eflag, deny_mask(mask, flags), whotype, owner);
 185         return error;
 186 }
 187
 188 /* We assume the acl has been verified with posix_acl_valid. */
 189 static int
 190 _posix_to_nfsv4_one(struct posix_acl *pacl, struct nfs4_acl *acl,
 191                                                 unsigned int flags)
 192 {
 193         struct posix_acl_entry *pa, *pe, *group_owner_entry;
 194         int error = -EINVAL;
 195         u32 mask, mask_mask;
 196         int eflag = ((flags & NFS4_ACL_TYPE_DEFAULT) ?
 197                                         NFS4_INHERITANCE_FLAGS : 0);
 198
 199         BUG_ON(pacl->a_count < 3);
 200         pe = pacl->a_entries + pacl->a_count;
 201         pa = pe - 2; /* if mask entry exists, it's second from the last. */
 202         if (pa->e_tag == ACL_MASK)
 203                 mask_mask = deny_mask(mask_from_posix(pa->e_perm, flags), flags);
 204         else
 205                 mask_mask = 0;
 206
 207         pa = pacl->a_entries;
 208         BUG_ON(pa->e_tag != ACL_USER_OBJ);
 209         mask = mask_from_posix(pa->e_perm, flags | NFS4_ACL_OWNER);
 210         error = nfs4_acl_add_pair(acl, eflag, mask, NFS4_ACL_WHO_OWNER, 0, flags);
 211         if (error < 0)
 212                 goto out;
 213         pa++;
 214
 215         while (pa->e_tag == ACL_USER) {
 216                 mask = mask_from_posix(pa->e_perm, flags);
 217                 error = nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_DENIED_ACE_TYPE,
 218                                 eflag,  mask_mask, NFS4_ACL_WHO_NAMED, pa->e_id);
 219                 if (error < 0)
 220                         goto out;
 221
 222
 223                 error = nfs4_acl_add_pair(acl, eflag, mask,
 224                                 NFS4_ACL_WHO_NAMED, pa->e_id, flags);
 225                 if (error < 0)
 226                         goto out;
 227                 pa++;
 228         }
 229
 230         /* In the case of groups, we apply allow ACEs first, then deny ACEs,
 231          * since a user can be in more than one group.  */
 232
 233         /* allow ACEs */
 234
 235         if (pacl->a_count > 3) {
 236                 BUG_ON(pa->e_tag != ACL_GROUP_OBJ);
 237                 error = nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_DENIED_ACE_TYPE,
 238                                 NFS4_ACE_IDENTIFIER_GROUP | eflag, mask_mask,
 239                                 NFS4_ACL_WHO_GROUP, 0);
 240                 if (error < 0)
 241                         goto out;
 242         }
 243         group_owner_entry = pa;
 244         mask = mask_from_posix(pa->e_perm, flags);
 245         error = nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE,
 246                         NFS4_ACE_IDENTIFIER_GROUP | eflag, mask,
 247                         NFS4_ACL_WHO_GROUP, 0);
 248         if (error < 0)
 249                 goto out;
 250         pa++;
 251
 252         while (pa->e_tag == ACL_GROUP) {
 253                 mask = mask_from_posix(pa->e_perm, flags);
 254                 error = nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_DENIED_ACE_TYPE,
 255                                 NFS4_ACE_IDENTIFIER_GROUP | eflag, mask_mask,
 256                                 NFS4_ACL_WHO_NAMED, pa->e_id);
 257                 if (error < 0)
 258                         goto out;
 259
 260                 error = nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE,
 261                                 NFS4_ACE_IDENTIFIER_GROUP | eflag, mask,
 262                                 NFS4_ACL_WHO_NAMED, pa->e_id);
 263                 if (error < 0)
 264                         goto out;
 265                 pa++;
 266         }
 267
 268         /* deny ACEs */
 269
 270         pa = group_owner_entry;
 271         mask = mask_from_posix(pa->e_perm, flags);
 272         error = nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_DENIED_ACE_TYPE,
 273                         NFS4_ACE_IDENTIFIER_GROUP | eflag,
 274                         deny_mask(mask, flags), NFS4_ACL_WHO_GROUP, 0);
 275         if (error < 0)
 276                 goto out;
 277         pa++;
 278         while (pa->e_tag == ACL_GROUP) {
 279                 mask = mask_from_posix(pa->e_perm, flags);
 280                 error = nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_DENIED_ACE_TYPE,
 281                                 NFS4_ACE_IDENTIFIER_GROUP | eflag,
 282                                 deny_mask(mask, flags), NFS4_ACL_WHO_NAMED, pa->e_id);
 283                 if (error < 0)
 284                         goto out;
 285                 pa++;
 286         }
 287
 288         if (pa->e_tag == ACL_MASK)
 289                 pa++;
 290         BUG_ON(pa->e_tag != ACL_OTHER);
 291         mask = mask_from_posix(pa->e_perm, flags);
 292         error = nfs4_acl_add_pair(acl, eflag, mask, NFS4_ACL_WHO_EVERYONE, 0, flags);
 293
 294 out:
 295         return error;
 296 }
 297
 298 static void
 299 sort_pacl_range(struct posix_acl *pacl, int start, int end) {
 300         int sorted = 0, i;
 301         struct posix_acl_entry tmp;
 302
 303         /* We just do a bubble sort; easy to do in place, and we're not
 304          * expecting acl's to be long enough to justify anything more. */
 305         while (!sorted) {
 306                 sorted = 1;
 307                 for (i = start; i < end; i++) {
 308                         if (pacl->a_entries[i].e_id
 309                                         > pacl->a_entries[i+1].e_id) {
 310                                 sorted = 0;
 311                                 tmp = pacl->a_entries[i];
 312                                 pacl->a_entries[i] = pacl->a_entries[i+1];
 313                                 pacl->a_entries[i+1] = tmp;
 314                         }
 315                 }
 316         }
 317 }
 318
 319 static void
 320 sort_pacl(struct posix_acl *pacl)
 321 {
 322         /* posix_acl_valid requires that users and groups be in order
 323          * by uid/gid. */
 324         int i, j;
 325
 326         if (pacl->a_count <= 4)
 327                 return; /* no users or groups */
 328         i = 1;
 329         while (pacl->a_entries[i].e_tag == ACL_USER)
 330                 i++;
 331         sort_pacl_range(pacl, 1, i-1);
 332
 333         BUG_ON(pacl->a_entries[i].e_tag != ACL_GROUP_OBJ);
 334         j = i++;
 335         while (pacl->a_entries[j].e_tag == ACL_GROUP)
 336                 j++;
 337         sort_pacl_range(pacl, i, j-1);
 338         return;
 339 }
 340
 341 static int
 342 write_pace(struct nfs4_ace *ace, struct posix_acl *pacl,
 343                 struct posix_acl_entry **pace, short tag, unsigned int flags)
 344 {
 345         struct posix_acl_entry *this = *pace;
 346
 347         if (*pace == pacl->a_entries + pacl->a_count)
 348                 return -EINVAL; /* fell off the end */
 349         (*pace)++;
 350         this->e_tag = tag;
 351         if (tag == ACL_USER_OBJ)
 352                 flags |= NFS4_ACL_OWNER;
 353         if (mode_from_nfs4(ace->access_mask, &this->e_perm, flags))
 354                 return -EINVAL;
 355         this->e_id = (tag == ACL_USER || tag == ACL_GROUP ?
 356                         ace->who : ACL_UNDEFINED_ID);
 357         return 0;
 358 }
 359
 360 static struct nfs4_ace *
 361 get_next_v4_ace(struct list_head **p, struct list_head *head)
 362 {
 363         struct nfs4_ace *ace;
 364
 365         *p = (*p)->next;
 366         if (*p == head)
 367                 return NULL;
 368         ace = list_entry(*p, struct nfs4_ace, l_ace);
 369
 370         return ace;
 371 }
 372
 373 int
 374 nfs4_acl_nfsv4_to_posix(struct nfs4_acl *acl, struct posix_acl **pacl,
 375                 struct posix_acl **dpacl, unsigned int flags)
 376 {
 377         struct nfs4_acl *dacl;
 378         int error = -ENOMEM;
 379
 380         *pacl = NULL;
 381         *dpacl = NULL;
 382
 383         dacl = nfs4_acl_new();
 384         if (dacl == NULL)
 385                 goto out;
 386
 387         error = nfs4_acl_split(acl, dacl);
 388         if (error < 0)
 389                 goto out_acl;
 390
 391         if (pacl != NULL) {
 392                 if (acl->naces == 0) {
 393                         error = -ENODATA;
 394                         goto try_dpacl;
 395                 }
 396
 397                 *pacl = _nfsv4_to_posix_one(acl, flags);
 398                 if (IS_ERR(*pacl)) {
 399                         error = PTR_ERR(*pacl);
 400                         *pacl = NULL;
 401                         goto out_acl;
 402                 }
 403         }
 404
 405 try_dpacl:
 406         if (dpacl != NULL) {
 407                 if (dacl->naces == 0) {
 408                         if (pacl == NULL || *pacl == NULL)
 409                                 error = -ENODATA;
 410                         goto out_acl;
 411                 }
 412
 413                 error = 0;
 414                 *dpacl = _nfsv4_to_posix_one(dacl, flags);
 415                 if (IS_ERR(*dpacl)) {
 416                         error = PTR_ERR(*dpacl);
 417                         *dpacl = NULL;
 418                         goto out_acl;
 419                 }
 420         }
 421
 422 out_acl:
 423         if (error && pacl) {
 424                 posix_acl_release(*pacl);
 425                 *pacl = NULL;
 426         }
 427         nfs4_acl_free(dacl);
 428 out:
 429         return error;
 430 }
 431
 432 static int
 433 same_who(struct nfs4_ace *a, struct nfs4_ace *b)
 434 {
 435         return a->whotype == b->whotype &&
 436                 (a->whotype != NFS4_ACL_WHO_NAMED || a->who == b->who);
 437 }
 438
 439 static int
 440 complementary_ace_pair(struct nfs4_ace *allow, struct nfs4_ace *deny,
 441                 unsigned int flags)
 442 {
 443         int ignore = 0;
 444         if (!(flags & NFS4_ACL_DIR))
 445                 ignore |= NFS4_ACE_DELETE_CHILD;
 446         return MASK_EQUAL(ignore|deny_mask(allow->access_mask, flags),
 447                           ignore|deny->access_mask) &&
 448                 allow->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE &&
 449                 deny->type == NFS4_ACE_ACCESS_DENIED_ACE_TYPE &&
 450                 allow->flag == deny->flag &&
 451                 same_who(allow, deny);
 452 }
 453
 454 static inline int
 455 user_obj_from_v4(struct nfs4_acl *n4acl, struct list_head **p,
 456                 struct posix_acl *pacl, struct posix_acl_entry **pace,
 457                 unsigned int flags)
 458 {
 459         int error = -EINVAL;
 460         struct nfs4_ace *ace, *ace2;
 461
 462         ace = get_next_v4_ace(p, &n4acl->ace_head);
 463         if (ace == NULL)
 464                 goto out;
 465         if (ace2type(ace) != ACL_USER_OBJ)
 466                 goto out;
 467         error = write_pace(ace, pacl, pace, ACL_USER_OBJ, flags);
 468         if (error < 0)
 469                 goto out;
 470         error = -EINVAL;
 471         ace2 = get_next_v4_ace(p, &n4acl->ace_head);
 472         if (ace2 == NULL)
 473                 goto out;
 474         if (!complementary_ace_pair(ace, ace2, flags))
 475                 goto out;
 476         error = 0;
 477 out:
 478         return error;
 479 }
 480
 481 static inline int
 482 users_from_v4(struct nfs4_acl *n4acl, struct list_head **p,
 483                 struct nfs4_ace **mask_ace,
 484                 struct posix_acl *pacl, struct posix_acl_entry **pace,
 485                 unsigned int flags)
 486 {
 487         int error = -EINVAL;
 488         struct nfs4_ace *ace, *ace2;
 489
 490         ace = get_next_v4_ace(p, &n4acl->ace_head);
 491         if (ace == NULL)
 492                 goto out;
 493         while (ace2type(ace) == ACL_USER) {
 494                 if (ace->type != NFS4_ACE_ACCESS_DENIED_ACE_TYPE)
 495                         goto out;
 496                 if (*mask_ace &&
 497                         !MASK_EQUAL(ace->access_mask, (*mask_ace)->access_mask))
 498                         goto out;
 499                 *mask_ace = ace;
 500                 ace = get_next_v4_ace(p, &n4acl->ace_head);
 501                 if (ace == NULL)
 502                         goto out;
 503                 if (ace->type != NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE)
 504                         goto out;
 505                 error = write_pace(ace, pacl, pace, ACL_USER, flags);
 506                 if (error < 0)
 507                         goto out;
 508                 error = -EINVAL;
 509                 ace2 = get_next_v4_ace(p, &n4acl->ace_head);
 510                 if (ace2 == NULL)
 511                         goto out;
 512                 if (!complementary_ace_pair(ace, ace2, flags))
 513                         goto out;
 514                 if ((*mask_ace)->flag != ace2->flag ||
 515                                 !same_who(*mask_ace, ace2))
 516                         goto out;
 517                 ace = get_next_v4_ace(p, &n4acl->ace_head);
 518                 if (ace == NULL)
 519                         goto out;
 520         }
 521         error = 0;
 522 out:
 523         return error;
 524 }
 525
 526 static inline int
 527 group_obj_and_groups_from_v4(struct nfs4_acl *n4acl, struct list_head **p,
 528                 struct nfs4_ace **mask_ace,
 529                 struct posix_acl *pacl, struct posix_acl_entry **pace,
 530                 unsigned int flags)
 531 {
 532         int error = -EINVAL;
 533         struct nfs4_ace *ace, *ace2;
 534         struct ace_container *ac;
 535         struct list_head group_l;
 536
 537         INIT_LIST_HEAD(&group_l);
 538         ace = list_entry(*p, struct nfs4_ace, l_ace);
 539
 540         /* group owner (mask and allow aces) */
 541
 542         if (pacl->a_count != 3) {
 543                 /* then the group owner should be preceded by mask */
 544                 if (ace->type != NFS4_ACE_ACCESS_DENIED_ACE_TYPE)
 545                         goto out;
 546                 if (*mask_ace &&
 547                         !MASK_EQUAL(ace->access_mask, (*mask_ace)->access_mask))
 548                         goto out;
 549                 *mask_ace = ace;
 550                 ace = get_next_v4_ace(p, &n4acl->ace_head);
 551                 if (ace == NULL)
 552                         goto out;
 553
 554                 if ((*mask_ace)->flag != ace->flag || !same_who(*mask_ace, ace))
 555                         goto out;
 556         }
 557
 558         if (ace2type(ace) != ACL_GROUP_OBJ)
 559                 goto out;
 560
 561         ac = kmalloc(sizeof(*ac), GFP_KERNEL);
 562         error = -ENOMEM;
 563         if (ac == NULL)
 564                 goto out;
 565         ac->ace = ace;
 566         list_add_tail(&ac->ace_l, &group_l);
 567
 568         error = -EINVAL;
 569         if (ace->type != NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE)
 570                 goto out;
 571
 572         error = write_pace(ace, pacl, pace, ACL_GROUP_OBJ, flags);
 573         if (error < 0)
 574                 goto out;
 575
 576         error = -EINVAL;
 577         ace = get_next_v4_ace(p, &n4acl->ace_head);
 578         if (ace == NULL)
 579                 goto out;
 580
 581         /* groups (mask and allow aces) */
 582
 583         while (ace2type(ace) == ACL_GROUP) {
 584                 if (*mask_ace == NULL)
 585                         goto out;
 586
 587                 if (ace->type != NFS4_ACE_ACCESS_DENIED_ACE_TYPE ||
 588                         !MASK_EQUAL(ace->access_mask, (*mask_ace)->access_mask))
 589                         goto out;
 590                 *mask_ace = ace;
 591
 592                 ace = get_next_v4_ace(p, &n4acl->ace_head);
 593                 if (ace == NULL)
 594                         goto out;
 595                 ac = kmalloc(sizeof(*ac), GFP_KERNEL);
 596                 error = -ENOMEM;
 597                 if (ac == NULL)
 598                         goto out;
 599                 error = -EINVAL;
 600                 if (ace->type != NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE ||
 601                                 !same_who(ace, *mask_ace))
 602                         goto out;
 603
 604                 ac->ace = ace;
 605                 list_add_tail(&ac->ace_l, &group_l);
 606
 607                 error = write_pace(ace, pacl, pace, ACL_GROUP, flags);
 608                 if (error < 0)
 609                         goto out;
 610                 error = -EINVAL;
 611                 ace = get_next_v4_ace(p, &n4acl->ace_head);
 612                 if (ace == NULL)
 613                         goto out;
 614         }
 615
 616         /* group owner (deny ace) */
 617
 618         if (ace2type(ace) != ACL_GROUP_OBJ)
 619                 goto out;
 620         ac = list_entry(group_l.next, struct ace_container, ace_l);
 621         ace2 = ac->ace;
 622         if (!complementary_ace_pair(ace2, ace, flags))
 623                 goto out;
 624         list_del(group_l.next);
 625         kfree(ac);
 626
 627         /* groups (deny aces) */
 628
 629         while (!list_empty(&group_l)) {
 630                 ace = get_next_v4_ace(p, &n4acl->ace_head);
 631                 if (ace == NULL)
 632                         goto out;
 633                 if (ace2type(ace) != ACL_GROUP)
 634                         goto out;
 635                 ac = list_entry(group_l.next, struct ace_container, ace_l);
 636                 ace2 = ac->ace;
 637                 if (!complementary_ace_pair(ace2, ace, flags))
 638                         goto out;
 639                 list_del(group_l.next);
 640                 kfree(ac);
 641         }
 642
 643         ace = get_next_v4_ace(p, &n4acl->ace_head);
 644         if (ace == NULL)
 645                 goto out;
 646         if (ace2type(ace) != ACL_OTHER)
 647                 goto out;
 648         error = 0;
 649 out:
 650         while (!list_empty(&group_l)) {
 651                 ac = list_entry(group_l.next, struct ace_container, ace_l);
 652                 list_del(group_l.next);
 653                 kfree(ac);
 654         }
 655         return error;
 656 }
 657
 658 static inline int
 659 mask_from_v4(struct nfs4_acl *n4acl, struct list_head **p,
 660                 struct nfs4_ace **mask_ace,
 661                 struct posix_acl *pacl, struct posix_acl_entry **pace,
 662                 unsigned int flags)
 663 {
 664         int error = -EINVAL;
 665         struct nfs4_ace *ace;
 666
 667         ace = list_entry(*p, struct nfs4_ace, l_ace);
 668         if (pacl->a_count != 3) {
 669                 if (*mask_ace == NULL)
 670                         goto out;
 671                 (*mask_ace)->access_mask = deny_mask((*mask_ace)->access_mask, flags);
 672                 write_pace(*mask_ace, pacl, pace, ACL_MASK, flags);
 673         }
 674         error = 0;
 675 out:
 676         return error;
 677 }
 678
 679 static inline int
 680 other_from_v4(struct nfs4_acl *n4acl, struct list_head **p,
 681                 struct posix_acl *pacl, struct posix_acl_entry **pace,
 682                 unsigned int flags)
 683 {
 684         int error = -EINVAL;
 685         struct nfs4_ace *ace, *ace2;
 686
 687         ace = list_entry(*p, struct nfs4_ace, l_ace);
 688         if (ace->type != NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE)
 689                 goto out;
 690         error = write_pace(ace, pacl, pace, ACL_OTHER, flags);
 691         if (error < 0)
 692                 goto out;
 693         error = -EINVAL;
 694         ace2 = get_next_v4_ace(p, &n4acl->ace_head);
 695         if (ace2 == NULL)
 696                 goto out;
 697         if (!complementary_ace_pair(ace, ace2, flags))
 698                 goto out;
 699         error = 0;
 700 out:
 701         return error;
 702 }
 703
 704 static int
 705 calculate_posix_ace_count(struct nfs4_acl *n4acl)
 706 {
 707         if (n4acl->naces == 6) /* owner, owner group, and other only */
 708                 return 3;
 709         else { /* Otherwise there must be a mask entry. */
 710                 /* Also, the remaining entries are for named users and
 711                  * groups, and come in threes (mask, allow, deny): */
 712                 if (n4acl->naces < 7)
 713                         return -EINVAL;
 714                 if ((n4acl->naces - 7) % 3)
 715                         return -EINVAL;
 716                 return 4 + (n4acl->naces - 7)/3;
 717         }
 718 }
 719
 720
 721 static struct posix_acl *
 722 _nfsv4_to_posix_one(struct nfs4_acl *n4acl, unsigned int flags)
 723 {
 724         struct posix_acl *pacl;
 725         int error = -EINVAL, nace = 0;
 726         struct list_head *p;
 727         struct nfs4_ace *mask_ace = NULL;
 728         struct posix_acl_entry *pace;
 729
 730         nace = calculate_posix_ace_count(n4acl);
 731         if (nace < 0)
 732                 goto out_err;
 733
 734         pacl = posix_acl_alloc(nace, GFP_KERNEL);
 735         error = -ENOMEM;
 736         if (pacl == NULL)
 737                 goto out_err;
 738
 739         pace = &pacl->a_entries[0];
 740         p = &n4acl->ace_head;
 741
 742         error = user_obj_from_v4(n4acl, &p, pacl, &pace, flags);
 743         if (error)
 744                 goto out_acl;
 745
 746         error = users_from_v4(n4acl, &p, &mask_ace, pacl, &pace, flags);
 747         if (error)
 748                 goto out_acl;
 749
 750         error = group_obj_and_groups_from_v4(n4acl, &p, &mask_ace, pacl, &pace,
 751                                                 flags);
 752         if (error)
 753                 goto out_acl;
 754
 755         error = mask_from_v4(n4acl, &p, &mask_ace, pacl, &pace, flags);
 756         if (error)
 757                 goto out_acl;
 758         error = other_from_v4(n4acl, &p, pacl, &pace, flags);
 759         if (error)
 760                 goto out_acl;
 761
 762         error = -EINVAL;
 763         if (p->next != &n4acl->ace_head)
 764                 goto out_acl;
 765         if (pace != pacl->a_entries + pacl->a_count)
 766                 goto out_acl;
 767
 768         sort_pacl(pacl);
 769
 770         return pacl;
 771 out_acl:
 772         posix_acl_release(pacl);
 773 out_err:
 774         pacl = ERR_PTR(error);
 775         return pacl;
 776 }
 777
 778 static int
 779 nfs4_acl_split(struct nfs4_acl *acl, struct nfs4_acl *dacl)
 780 {
 781         struct list_head *h, *n;
 782         struct nfs4_ace *ace;
 783         int error = 0;
 784
 785         list_for_each_safe(h, n, &acl->ace_head) {
 786                 ace = list_entry(h, struct nfs4_ace, l_ace);
 787
 788                 if ((ace->flag & NFS4_INHERITANCE_FLAGS)
 789                                 != NFS4_INHERITANCE_FLAGS)
 790                         continue;
 791
 792                 error = nfs4_acl_add_ace(dacl, ace->type, ace->flag,
 793                                 ace->access_mask, ace->whotype, ace->who);
 794                 if (error < 0)
 795                         goto out;
 796
 797                 list_del(h);
 798                 kfree(ace);
 799                 acl->naces--;
 800         }
 801
 802 out:
 803         return error;
 804 }
 805
 806 static short
 807 ace2type(struct nfs4_ace *ace)
 808 {
 809         switch (ace->whotype) {
 810                 case NFS4_ACL_WHO_NAMED:
 811                         return (ace->flag & NFS4_ACE_IDENTIFIER_GROUP ?
 812                                         ACL_GROUP : ACL_USER);
 813                 case NFS4_ACL_WHO_OWNER:
 814                         return ACL_USER_OBJ;
 815                 case NFS4_ACL_WHO_GROUP:
 816                         return ACL_GROUP_OBJ;
 817                 case NFS4_ACL_WHO_EVERYONE:
 818                         return ACL_OTHER;
 819         }
 820         BUG();
 821         return -1;
 822 }
 823
 824 EXPORT_SYMBOL(nfs4_acl_posix_to_nfsv4);
 825 EXPORT_SYMBOL(nfs4_acl_nfsv4_to_posix);
 826
 827 struct nfs4_acl *
 828 nfs4_acl_new(void)
 829 {
 830         struct nfs4_acl *acl;
 831
 832         if ((acl = kmalloc(sizeof(*acl), GFP_KERNEL)) == NULL)
 833                 return NULL;
 834
 835         acl->naces = 0;
 836         INIT_LIST_HEAD(&acl->ace_head);
 837
 838         return acl;
 839 }
 840
 841 void
 842 nfs4_acl_free(struct nfs4_acl *acl)
 843 {
 844         struct list_head *h;
 845         struct nfs4_ace *ace;
 846
 847         if (!acl)
 848                 return;
 849
 850         while (!list_empty(&acl->ace_head)) {
 851                 h = acl->ace_head.next;
 852                 list_del(h);
 853                 ace = list_entry(h, struct nfs4_ace, l_ace);
 854                 kfree(ace);
 855         }
 856
 857         kfree(acl);
 858
 859         return;
 860 }
 861
 862 int
 863 nfs4_acl_add_ace(struct nfs4_acl *acl, u32 type, u32 flag, u32 access_mask,
 864                 int whotype, uid_t who)
 865 {
 866         struct nfs4_ace *ace;
 867
 868         if ((ace = kmalloc(sizeof(*ace), GFP_KERNEL)) == NULL)
 869                 return -ENOMEM;
 870
 871         ace->type = type;
 872         ace->flag = flag;
 873         ace->access_mask = access_mask;
 874         ace->whotype = whotype;
 875         ace->who = who;
 876
 877         list_add_tail(&ace->l_ace, &acl->ace_head);
 878         acl->naces++;
 879
 880         return 0;
 881 }
 882
 883 static struct {
 884         char *string;
 885         int   stringlen;
 886         int type;
 887 } s2t_map[] = {
 888         {
 889                 .string    = "OWNER@",
 890                 .stringlen = sizeof("OWNER@") - 1,
 891                 .type      = NFS4_ACL_WHO_OWNER,
 892         },
 893         {
 894                 .string    = "GROUP@",
 895                 .stringlen = sizeof("GROUP@") - 1,
 896                 .type      = NFS4_ACL_WHO_GROUP,
 897         },
 898         {
 899                 .string    = "EVERYONE@",
 900                 .stringlen = sizeof("EVERYONE@") - 1,
 901                 .type      = NFS4_ACL_WHO_EVERYONE,
 902         },
 903 };
 904
 905 int
 906 nfs4_acl_get_whotype(char *p, u32 len)
 907 {
 908         int i;
 909
 910         for (i = 0; i < ARRAY_SIZE(s2t_map); i++) {
 911                 if (s2t_map[i].stringlen == len &&
 912                                 0 == memcmp(s2t_map[i].string, p, len))
 913                         return s2t_map[i].type;
 914         }
 915         return NFS4_ACL_WHO_NAMED;
 916 }
 917
 918 int
 919 nfs4_acl_write_who(int who, char *p)
 920 {
 921         int i;
 922
 923         for (i = 0; i < ARRAY_SIZE(s2t_map); i++) {
 924                 if (s2t_map[i].type == who) {
 925                         memcpy(p, s2t_map[i].string, s2t_map[i].stringlen);
 926                         return s2t_map[i].stringlen;
 927                 }
 928         }
 929         BUG();
 930         return -1;
 931 }
 932
 933 static inline int
 934 match_who(struct nfs4_ace *ace, uid_t owner, gid_t group, uid_t who)
 935 {
 936         switch (ace->whotype) {
 937                 case NFS4_ACL_WHO_NAMED:
 938                         return who == ace->who;
 939                 case NFS4_ACL_WHO_OWNER:
 940                         return who == owner;
 941                 case NFS4_ACL_WHO_GROUP:
 942                         return who == group;
 943                 case NFS4_ACL_WHO_EVERYONE:
 944                         return 1;
 945                 default:
 946                         return 0;
 947         }
 948 }
 949
 950 EXPORT_SYMBOL(nfs4_acl_new);
 951 EXPORT_SYMBOL(nfs4_acl_free);
 952 EXPORT_SYMBOL(nfs4_acl_add_ace);
 953 EXPORT_SYMBOL(nfs4_acl_get_whotype);
 954 EXPORT_SYMBOL(nfs4_acl_write_who);