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