fs/reiserfs/xattr_acl.c

   1 #include <linux/capability.h>
   2 #include <linux/fs.h>
   3 #include <linux/posix_acl.h>
   4 #include <linux/reiserfs_fs.h>
   5 #include <linux/errno.h>
   6 #include <linux/pagemap.h>
   7 #include <linux/xattr.h>
   8 #include <linux/posix_acl_xattr.h>
   9 #include <linux/reiserfs_xattr.h>
  10 #include <linux/reiserfs_acl.h>
  11 #include <asm/uaccess.h>
  12
  13 static int reiserfs_set_acl(struct reiserfs_transaction_handle *th,
  14                             struct inode *inode, int type,
  15                             struct posix_acl *acl);
  16
  17 static int
  18 xattr_set_acl(struct inode *inode, int type, const void *value, size_t size)
  19 {
  20         struct posix_acl *acl;
  21         int error, error2;
  22         struct reiserfs_transaction_handle th;
  23         size_t jcreate_blocks;
  24         if (!reiserfs_posixacl(inode->i_sb))
  25                 return -EOPNOTSUPP;
  26         if (!is_owner_or_cap(inode))
  27                 return -EPERM;
  28
  29         if (value) {
  30                 acl = posix_acl_from_xattr(value, size);
  31                 if (IS_ERR(acl)) {
  32                         return PTR_ERR(acl);
  33                 } else if (acl) {
  34                         error = posix_acl_valid(acl);
  35                         if (error)
  36                                 goto release_and_out;
  37                 }
  38         } else
  39                 acl = NULL;
  40
  41         /* Pessimism: We can't assume that anything from the xattr root up
  42          * has been created. */
  43
  44         jcreate_blocks = reiserfs_xattr_jcreate_nblocks(inode) +
  45                          reiserfs_xattr_nblocks(inode, size) * 2;
  46
  47         reiserfs_write_lock(inode->i_sb);
  48         error = journal_begin(&th, inode->i_sb, jcreate_blocks);
  49         if (error == 0) {
  50                 error = reiserfs_set_acl(&th, inode, type, acl);
  51                 error2 = journal_end(&th, inode->i_sb, jcreate_blocks);
  52                 if (error2)
  53                         error = error2;
  54         }
  55         reiserfs_write_unlock(inode->i_sb);
  56
  57       release_and_out:
  58         posix_acl_release(acl);
  59         return error;
  60 }
  61
  62 static int
  63 xattr_get_acl(struct inode *inode, int type, void *buffer, size_t size)
  64 {
  65         struct posix_acl *acl;
  66         int error;
  67
  68         if (!reiserfs_posixacl(inode->i_sb))
  69                 return -EOPNOTSUPP;
  70
  71         acl = reiserfs_get_acl(inode, type);
  72         if (IS_ERR(acl))
  73                 return PTR_ERR(acl);
  74         if (acl == NULL)
  75                 return -ENODATA;
  76         error = posix_acl_to_xattr(acl, buffer, size);
  77         posix_acl_release(acl);
  78
  79         return error;
  80 }
  81
  82 /*
  83  * Convert from filesystem to in-memory representation.
  84  */
  85 static struct posix_acl *posix_acl_from_disk(const void *value, size_t size)
  86 {
  87         const char *end = (char *)value + size;
  88         int n, count;
  89         struct posix_acl *acl;
  90
  91         if (!value)
  92                 return NULL;
  93         if (size < sizeof(reiserfs_acl_header))
  94                 return ERR_PTR(-EINVAL);
  95         if (((reiserfs_acl_header *) value)->a_version !=
  96             cpu_to_le32(REISERFS_ACL_VERSION))
  97                 return ERR_PTR(-EINVAL);
  98         value = (char *)value + sizeof(reiserfs_acl_header);
  99         count = reiserfs_acl_count(size);
 100         if (count < 0)
 101                 return ERR_PTR(-EINVAL);
 102         if (count == 0)
 103                 return NULL;
 104         acl = posix_acl_alloc(count, GFP_NOFS);
 105         if (!acl)
 106                 return ERR_PTR(-ENOMEM);
 107         for (n = 0; n < count; n++) {
 108                 reiserfs_acl_entry *entry = (reiserfs_acl_entry *) value;
 109                 if ((char *)value + sizeof(reiserfs_acl_entry_short) > end)
 110                         goto fail;
 111                 acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag);
 112                 acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
 113                 switch (acl->a_entries[n].e_tag) {
 114                 case ACL_USER_OBJ:
 115                 case ACL_GROUP_OBJ:
 116                 case ACL_MASK:
 117                 case ACL_OTHER:
 118                         value = (char *)value +
 119                             sizeof(reiserfs_acl_entry_short);
 120                         acl->a_entries[n].e_id = ACL_UNDEFINED_ID;
 121                         break;
 122
 123                 case ACL_USER:
 124                 case ACL_GROUP:
 125                         value = (char *)value + sizeof(reiserfs_acl_entry);
 126                         if ((char *)value > end)
 127                                 goto fail;
 128                         acl->a_entries[n].e_id = le32_to_cpu(entry->e_id);
 129                         break;
 130
 131                 default:
 132                         goto fail;
 133                 }
 134         }
 135         if (value != end)
 136                 goto fail;
 137         return acl;
 138
 139       fail:
 140         posix_acl_release(acl);
 141         return ERR_PTR(-EINVAL);
 142 }
 143
 144 /*
 145  * Convert from in-memory to filesystem representation.
 146  */
 147 static void *posix_acl_to_disk(const struct posix_acl *acl, size_t * size)
 148 {
 149         reiserfs_acl_header *ext_acl;
 150         char *e;
 151         int n;
 152
 153         *size = reiserfs_acl_size(acl->a_count);
 154         ext_acl = kmalloc(sizeof(reiserfs_acl_header) +
 155                                                   acl->a_count *
 156                                                   sizeof(reiserfs_acl_entry),
 157                                                   GFP_NOFS);
 158         if (!ext_acl)
 159                 return ERR_PTR(-ENOMEM);
 160         ext_acl->a_version = cpu_to_le32(REISERFS_ACL_VERSION);
 161         e = (char *)ext_acl + sizeof(reiserfs_acl_header);
 162         for (n = 0; n < acl->a_count; n++) {
 163                 reiserfs_acl_entry *entry = (reiserfs_acl_entry *) e;
 164                 entry->e_tag = cpu_to_le16(acl->a_entries[n].e_tag);
 165                 entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
 166                 switch (acl->a_entries[n].e_tag) {
 167                 case ACL_USER:
 168                 case ACL_GROUP:
 169                         entry->e_id = cpu_to_le32(acl->a_entries[n].e_id);
 170                         e += sizeof(reiserfs_acl_entry);
 171                         break;
 172
 173                 case ACL_USER_OBJ:
 174                 case ACL_GROUP_OBJ:
 175                 case ACL_MASK:
 176                 case ACL_OTHER:
 177                         e += sizeof(reiserfs_acl_entry_short);
 178                         break;
 179
 180                 default:
 181                         goto fail;
 182                 }
 183         }
 184         return (char *)ext_acl;
 185
 186       fail:
 187         kfree(ext_acl);
 188         return ERR_PTR(-EINVAL);
 189 }
 190
 191 /*
 192  * Inode operation get_posix_acl().
 193  *
 194  * inode->i_mutex: down
 195  * BKL held [before 2.5.x]
 196  */
 197 struct posix_acl *reiserfs_get_acl(struct inode *inode, int type)
 198 {
 199         char *name, *value;
 200         struct posix_acl *acl;
 201         int size;
 202         int retval;
 203
 204         acl = get_cached_acl(inode, type);
 205         if (acl != ACL_NOT_CACHED)
 206                 return acl;
 207
 208         switch (type) {
 209         case ACL_TYPE_ACCESS:
 210                 name = POSIX_ACL_XATTR_ACCESS;
 211                 break;
 212         case ACL_TYPE_DEFAULT:
 213                 name = POSIX_ACL_XATTR_DEFAULT;
 214                 break;
 215         default:
 216                 BUG();
 217         }
 218
 219         size = reiserfs_xattr_get(inode, name, NULL, 0);
 220         if (size < 0) {
 221                 if (size == -ENODATA || size == -ENOSYS) {
 222                         set_cached_acl(inode, type, NULL);
 223                         return NULL;
 224                 }
 225                 return ERR_PTR(size);
 226         }
 227
 228         value = kmalloc(size, GFP_NOFS);
 229         if (!value)
 230                 return ERR_PTR(-ENOMEM);
 231
 232         retval = reiserfs_xattr_get(inode, name, value, size);
 233         if (retval == -ENODATA || retval == -ENOSYS) {
 234                 /* This shouldn't actually happen as it should have
 235                    been caught above.. but just in case */
 236                 acl = NULL;
 237         } else if (retval < 0) {
 238                 acl = ERR_PTR(retval);
 239         } else {
 240                 acl = posix_acl_from_disk(value, retval);
 241         }
 242         if (!IS_ERR(acl))
 243                 set_cached_acl(inode, type, acl);
 244
 245         kfree(value);
 246         return acl;
 247 }
 248
 249 /*
 250  * Inode operation set_posix_acl().
 251  *
 252  * inode->i_mutex: down
 253  * BKL held [before 2.5.x]
 254  */
 255 static int
 256 reiserfs_set_acl(struct reiserfs_transaction_handle *th, struct inode *inode,
 257                  int type, struct posix_acl *acl)
 258 {
 259         char *name;
 260         void *value = NULL;
 261         size_t size = 0;
 262         int error;
 263
 264         if (S_ISLNK(inode->i_mode))
 265                 return -EOPNOTSUPP;
 266
 267         switch (type) {
 268         case ACL_TYPE_ACCESS:
 269                 name = POSIX_ACL_XATTR_ACCESS;
 270                 if (acl) {
 271                         mode_t mode = inode->i_mode;
 272                         error = posix_acl_equiv_mode(acl, &mode);
 273                         if (error < 0)
 274                                 return error;
 275                         else {
 276                                 inode->i_mode = mode;
 277                                 if (error == 0)
 278                                         acl = NULL;
 279                         }
 280                 }
 281                 break;
 282         case ACL_TYPE_DEFAULT:
 283                 name = POSIX_ACL_XATTR_DEFAULT;
 284                 if (!S_ISDIR(inode->i_mode))
 285                         return acl ? -EACCES : 0;
 286                 break;
 287         default:
 288                 return -EINVAL;
 289         }
 290
 291         if (acl) {
 292                 value = posix_acl_to_disk(acl, &size);
 293                 if (IS_ERR(value))
 294                         return (int)PTR_ERR(value);
 295         }
 296
 297         error = reiserfs_xattr_set_handle(th, inode, name, value, size, 0);
 298
 299         /*
 300          * Ensure that the inode gets dirtied if we're only using
 301          * the mode bits and an old ACL didn't exist. We don't need
 302          * to check if the inode is hashed here since we won't get
 303          * called by reiserfs_inherit_default_acl().
 304          */
 305         if (error == -ENODATA) {
 306                 error = 0;
 307                 if (type == ACL_TYPE_ACCESS) {
 308                         inode->i_ctime = CURRENT_TIME_SEC;
 309                         mark_inode_dirty(inode);
 310                 }
 311         }
 312
 313         kfree(value);
 314
 315         if (!error)
 316                 set_cached_acl(inode, type, acl);
 317
 318         return error;
 319 }
 320
 321 /* dir->i_mutex: locked,
 322  * inode is new and not released into the wild yet */
 323 int
 324 reiserfs_inherit_default_acl(struct reiserfs_transaction_handle *th,
 325                              struct inode *dir, struct dentry *dentry,
 326                              struct inode *inode)
 327 {
 328         struct posix_acl *acl;
 329         int err = 0;
 330
 331         /* ACLs only get applied to files and directories */
 332         if (S_ISLNK(inode->i_mode))
 333                 return 0;
 334
 335         /* ACLs can only be used on "new" objects, so if it's an old object
 336          * there is nothing to inherit from */
 337         if (get_inode_sd_version(dir) == STAT_DATA_V1)
 338                 goto apply_umask;
 339
 340         /* Don't apply ACLs to objects in the .reiserfs_priv tree.. This
 341          * would be useless since permissions are ignored, and a pain because
 342          * it introduces locking cycles */
 343         if (IS_PRIVATE(dir)) {
 344                 inode->i_flags |= S_PRIVATE;
 345                 goto apply_umask;
 346         }
 347
 348         acl = reiserfs_get_acl(dir, ACL_TYPE_DEFAULT);
 349         if (IS_ERR(acl))
 350                 return PTR_ERR(acl);
 351
 352         if (acl) {
 353                 struct posix_acl *acl_copy;
 354                 mode_t mode = inode->i_mode;
 355                 int need_acl;
 356
 357                 /* Copy the default ACL to the default ACL of a new directory */
 358                 if (S_ISDIR(inode->i_mode)) {
 359                         err = reiserfs_set_acl(th, inode, ACL_TYPE_DEFAULT,
 360                                                acl);
 361                         if (err)
 362                                 goto cleanup;
 363                 }
 364
 365                 /* Now we reconcile the new ACL and the mode,
 366                    potentially modifying both */
 367                 acl_copy = posix_acl_clone(acl, GFP_NOFS);
 368                 if (!acl_copy) {
 369                         err = -ENOMEM;
 370                         goto cleanup;
 371                 }
 372
 373                 need_acl = posix_acl_create_masq(acl_copy, &mode);
 374                 if (need_acl >= 0) {
 375                         if (mode != inode->i_mode) {
 376                                 inode->i_mode = mode;
 377                         }
 378
 379                         /* If we need an ACL.. */
 380                         if (need_acl > 0) {
 381                                 err = reiserfs_set_acl(th, inode,
 382                                                        ACL_TYPE_ACCESS,
 383                                                        acl_copy);
 384                                 if (err)
 385                                         goto cleanup_copy;
 386                         }
 387                 }
 388               cleanup_copy:
 389                 posix_acl_release(acl_copy);
 390               cleanup:
 391                 posix_acl_release(acl);
 392         } else {
 393               apply_umask:
 394                 /* no ACL, apply umask */
 395                 inode->i_mode &= ~current_umask();
 396         }
 397
 398         return err;
 399 }
 400
 401 /* This is used to cache the default acl before a new object is created.
 402  * The biggest reason for this is to get an idea of how many blocks will
 403  * actually be required for the create operation if we must inherit an ACL.
 404  * An ACL write can add up to 3 object creations and an additional file write
 405  * so we'd prefer not to reserve that many blocks in the journal if we can.
 406  * It also has the advantage of not loading the ACL with a transaction open,
 407  * this may seem silly, but if the owner of the directory is doing the
 408  * creation, the ACL may not be loaded since the permissions wouldn't require
 409  * it.
 410  * We return the number of blocks required for the transaction.
 411  */
 412 int reiserfs_cache_default_acl(struct inode *inode)
 413 {
 414         struct posix_acl *acl;
 415         int nblocks = 0;
 416
 417         if (IS_PRIVATE(inode))
 418                 return 0;
 419
 420         acl = reiserfs_get_acl(inode, ACL_TYPE_DEFAULT);
 421
 422         if (acl && !IS_ERR(acl)) {
 423                 int size = reiserfs_acl_size(acl->a_count);
 424
 425                 /* Other xattrs can be created during inode creation. We don't
 426                  * want to claim too many blocks, so we check to see if we
 427                  * we need to create the tree to the xattrs, and then we
 428                  * just want two files. */
 429                 nblocks = reiserfs_xattr_jcreate_nblocks(inode);
 430                 nblocks += JOURNAL_BLOCKS_PER_OBJECT(inode->i_sb);
 431
 432                 REISERFS_I(inode)->i_flags |= i_has_xattr_dir;
 433
 434                 /* We need to account for writes + bitmaps for two files */
 435                 nblocks += reiserfs_xattr_nblocks(inode, size) * 4;
 436                 posix_acl_release(acl);
 437         }
 438
 439         return nblocks;
 440 }
 441
 442 int reiserfs_acl_chmod(struct inode *inode)
 443 {
 444         struct posix_acl *acl, *clone;
 445         int error;
 446
 447         if (S_ISLNK(inode->i_mode))
 448                 return -EOPNOTSUPP;
 449
 450         if (get_inode_sd_version(inode) == STAT_DATA_V1 ||
 451             !reiserfs_posixacl(inode->i_sb)) {
 452                 return 0;
 453         }
 454
 455         acl = reiserfs_get_acl(inode, ACL_TYPE_ACCESS);
 456         if (!acl)
 457                 return 0;
 458         if (IS_ERR(acl))
 459                 return PTR_ERR(acl);
 460         clone = posix_acl_clone(acl, GFP_NOFS);
 461         posix_acl_release(acl);
 462         if (!clone)
 463                 return -ENOMEM;
 464         error = posix_acl_chmod_masq(clone, inode->i_mode);
 465         if (!error) {
 466                 struct reiserfs_transaction_handle th;
 467                 size_t size = reiserfs_xattr_nblocks(inode,
 468                                              reiserfs_acl_size(clone->a_count));
 469                 reiserfs_write_lock(inode->i_sb);
 470                 error = journal_begin(&th, inode->i_sb, size * 2);
 471                 if (!error) {
 472                         int error2;
 473                         error = reiserfs_set_acl(&th, inode, ACL_TYPE_ACCESS,
 474                                                  clone);
 475                         error2 = journal_end(&th, inode->i_sb, size * 2);
 476                         if (error2)
 477                                 error = error2;
 478                 }
 479                 reiserfs_write_unlock(inode->i_sb);
 480         }
 481         posix_acl_release(clone);
 482         return error;
 483 }
 484
 485 static int
 486 posix_acl_access_get(struct inode *inode, const char *name,
 487                      void *buffer, size_t size)
 488 {
 489         if (strlen(name) != sizeof(POSIX_ACL_XATTR_ACCESS) - 1)
 490                 return -EINVAL;
 491         return xattr_get_acl(inode, ACL_TYPE_ACCESS, buffer, size);
 492 }
 493
 494 static int
 495 posix_acl_access_set(struct inode *inode, const char *name,
 496                      const void *value, size_t size, int flags)
 497 {
 498         if (strlen(name) != sizeof(POSIX_ACL_XATTR_ACCESS) - 1)
 499                 return -EINVAL;
 500         return xattr_set_acl(inode, ACL_TYPE_ACCESS, value, size);
 501 }
 502
 503 static size_t posix_acl_access_list(struct inode *inode, char *list,
 504                                     size_t list_size, const char *name,
 505                                     size_t name_len)
 506 {
 507         const size_t size = sizeof(POSIX_ACL_XATTR_ACCESS);
 508         if (!reiserfs_posixacl(inode->i_sb))
 509                 return 0;
 510         if (list && size <= list_size)
 511                 memcpy(list, POSIX_ACL_XATTR_ACCESS, size);
 512         return size;
 513 }
 514
 515 struct xattr_handler reiserfs_posix_acl_access_handler = {
 516         .prefix = POSIX_ACL_XATTR_ACCESS,
 517         .get = posix_acl_access_get,
 518         .set = posix_acl_access_set,
 519         .list = posix_acl_access_list,
 520 };
 521
 522 static int
 523 posix_acl_default_get(struct inode *inode, const char *name,
 524                       void *buffer, size_t size)
 525 {
 526         if (strlen(name) != sizeof(POSIX_ACL_XATTR_DEFAULT) - 1)
 527                 return -EINVAL;
 528         return xattr_get_acl(inode, ACL_TYPE_DEFAULT, buffer, size);
 529 }
 530
 531 static int
 532 posix_acl_default_set(struct inode *inode, const char *name,
 533                       const void *value, size_t size, int flags)
 534 {
 535         if (strlen(name) != sizeof(POSIX_ACL_XATTR_DEFAULT) - 1)
 536                 return -EINVAL;
 537         return xattr_set_acl(inode, ACL_TYPE_DEFAULT, value, size);
 538 }
 539
 540 static size_t posix_acl_default_list(struct inode *inode, char *list,
 541                                      size_t list_size, const char *name,
 542                                      size_t name_len)
 543 {
 544         const size_t size = sizeof(POSIX_ACL_XATTR_DEFAULT);
 545         if (!reiserfs_posixacl(inode->i_sb))
 546                 return 0;
 547         if (list && size <= list_size)
 548                 memcpy(list, POSIX_ACL_XATTR_DEFAULT, size);
 549         return size;
 550 }
 551
 552 struct xattr_handler reiserfs_posix_acl_default_handler = {
 553         .prefix = POSIX_ACL_XATTR_DEFAULT,
 554         .get = posix_acl_default_get,
 555         .set = posix_acl_default_set,
 556         .list = posix_acl_default_list,
 557 };