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 static inline void iset_acl(struct inode *inode, struct posix_acl **i_acl,
 192                             struct posix_acl *acl)
 193 {
 194         spin_lock(&inode->i_lock);
 195         if (*i_acl != ERR_PTR(-ENODATA))
 196                 posix_acl_release(*i_acl);
 197         *i_acl = posix_acl_dup(acl);
 198         spin_unlock(&inode->i_lock);
 199 }
 200
 201 static inline struct posix_acl *iget_acl(struct inode *inode,
 202                                          struct posix_acl **i_acl)
 203 {
 204         struct posix_acl *acl = ERR_PTR(-ENODATA);
 205
 206         spin_lock(&inode->i_lock);
 207         if (*i_acl != ERR_PTR(-ENODATA))
 208                 acl = posix_acl_dup(*i_acl);
 209         spin_unlock(&inode->i_lock);
 210
 211         return acl;
 212 }
 213
 214 /*
 215  * Inode operation get_posix_acl().
 216  *
 217  * inode->i_mutex: down
 218  * BKL held [before 2.5.x]
 219  */
 220 struct posix_acl *reiserfs_get_acl(struct inode *inode, int type)
 221 {
 222         char *name, *value;
 223         struct posix_acl *acl, **p_acl;
 224         int size;
 225         int retval;
 226         struct reiserfs_inode_info *reiserfs_i = REISERFS_I(inode);
 227
 228         switch (type) {
 229         case ACL_TYPE_ACCESS:
 230                 name = POSIX_ACL_XATTR_ACCESS;
 231                 p_acl = &reiserfs_i->i_acl_access;
 232                 break;
 233         case ACL_TYPE_DEFAULT:
 234                 name = POSIX_ACL_XATTR_DEFAULT;
 235                 p_acl = &reiserfs_i->i_acl_default;
 236                 break;
 237         default:
 238                 return ERR_PTR(-EINVAL);
 239         }
 240
 241         acl = iget_acl(inode, p_acl);
 242         if (acl && !IS_ERR(acl))
 243                 return acl;
 244         else if (PTR_ERR(acl) == -ENODATA)
 245                 return NULL;
 246
 247         size = reiserfs_xattr_get(inode, name, NULL, 0);
 248         if (size < 0) {
 249                 if (size == -ENODATA || size == -ENOSYS) {
 250                         *p_acl = ERR_PTR(-ENODATA);
 251                         return NULL;
 252                 }
 253                 return ERR_PTR(size);
 254         }
 255
 256         value = kmalloc(size, GFP_NOFS);
 257         if (!value)
 258                 return ERR_PTR(-ENOMEM);
 259
 260         retval = reiserfs_xattr_get(inode, name, value, size);
 261         if (retval == -ENODATA || retval == -ENOSYS) {
 262                 /* This shouldn't actually happen as it should have
 263                    been caught above.. but just in case */
 264                 acl = NULL;
 265                 *p_acl = ERR_PTR(-ENODATA);
 266         } else if (retval < 0) {
 267                 acl = ERR_PTR(retval);
 268         } else {
 269                 acl = posix_acl_from_disk(value, retval);
 270                 if (!IS_ERR(acl))
 271                         iset_acl(inode, p_acl, acl);
 272         }
 273
 274         kfree(value);
 275         return acl;
 276 }
 277
 278 /*
 279  * Inode operation set_posix_acl().
 280  *
 281  * inode->i_mutex: down
 282  * BKL held [before 2.5.x]
 283  */
 284 static int
 285 reiserfs_set_acl(struct reiserfs_transaction_handle *th, struct inode *inode,
 286                  int type, struct posix_acl *acl)
 287 {
 288         char *name;
 289         void *value = NULL;
 290         struct posix_acl **p_acl;
 291         size_t size = 0;
 292         int error;
 293         struct reiserfs_inode_info *reiserfs_i = REISERFS_I(inode);
 294
 295         if (S_ISLNK(inode->i_mode))
 296                 return -EOPNOTSUPP;
 297
 298         switch (type) {
 299         case ACL_TYPE_ACCESS:
 300                 name = POSIX_ACL_XATTR_ACCESS;
 301                 p_acl = &reiserfs_i->i_acl_access;
 302                 if (acl) {
 303                         mode_t mode = inode->i_mode;
 304                         error = posix_acl_equiv_mode(acl, &mode);
 305                         if (error < 0)
 306                                 return error;
 307                         else {
 308                                 inode->i_mode = mode;
 309                                 if (error == 0)
 310                                         acl = NULL;
 311                         }
 312                 }
 313                 break;
 314         case ACL_TYPE_DEFAULT:
 315                 name = POSIX_ACL_XATTR_DEFAULT;
 316                 p_acl = &reiserfs_i->i_acl_default;
 317                 if (!S_ISDIR(inode->i_mode))
 318                         return acl ? -EACCES : 0;
 319                 break;
 320         default:
 321                 return -EINVAL;
 322         }
 323
 324         if (acl) {
 325                 value = posix_acl_to_disk(acl, &size);
 326                 if (IS_ERR(value))
 327                         return (int)PTR_ERR(value);
 328         }
 329
 330         error = reiserfs_xattr_set_handle(th, inode, name, value, size, 0);
 331
 332         /*
 333          * Ensure that the inode gets dirtied if we're only using
 334          * the mode bits and an old ACL didn't exist. We don't need
 335          * to check if the inode is hashed here since we won't get
 336          * called by reiserfs_inherit_default_acl().
 337          */
 338         if (error == -ENODATA) {
 339                 error = 0;
 340                 if (type == ACL_TYPE_ACCESS) {
 341                         inode->i_ctime = CURRENT_TIME_SEC;
 342                         mark_inode_dirty(inode);
 343                 }
 344         }
 345
 346         kfree(value);
 347
 348         if (!error)
 349                 iset_acl(inode, p_acl, acl);
 350
 351         return error;
 352 }
 353
 354 /* dir->i_mutex: locked,
 355  * inode is new and not released into the wild yet */
 356 int
 357 reiserfs_inherit_default_acl(struct reiserfs_transaction_handle *th,
 358                              struct inode *dir, struct dentry *dentry,
 359                              struct inode *inode)
 360 {
 361         struct posix_acl *acl;
 362         int err = 0;
 363
 364         /* ACLs only get applied to files and directories */
 365         if (S_ISLNK(inode->i_mode))
 366                 return 0;
 367
 368         /* ACLs can only be used on "new" objects, so if it's an old object
 369          * there is nothing to inherit from */
 370         if (get_inode_sd_version(dir) == STAT_DATA_V1)
 371                 goto apply_umask;
 372
 373         /* Don't apply ACLs to objects in the .reiserfs_priv tree.. This
 374          * would be useless since permissions are ignored, and a pain because
 375          * it introduces locking cycles */
 376         if (IS_PRIVATE(dir)) {
 377                 inode->i_flags |= S_PRIVATE;
 378                 goto apply_umask;
 379         }
 380
 381         acl = reiserfs_get_acl(dir, ACL_TYPE_DEFAULT);
 382         if (IS_ERR(acl)) {
 383                 if (PTR_ERR(acl) == -ENODATA)
 384                         goto apply_umask;
 385                 return PTR_ERR(acl);
 386         }
 387
 388         if (acl) {
 389                 struct posix_acl *acl_copy;
 390                 mode_t mode = inode->i_mode;
 391                 int need_acl;
 392
 393                 /* Copy the default ACL to the default ACL of a new directory */
 394                 if (S_ISDIR(inode->i_mode)) {
 395                         err = reiserfs_set_acl(th, inode, ACL_TYPE_DEFAULT,
 396                                                acl);
 397                         if (err)
 398                                 goto cleanup;
 399                 }
 400
 401                 /* Now we reconcile the new ACL and the mode,
 402                    potentially modifying both */
 403                 acl_copy = posix_acl_clone(acl, GFP_NOFS);
 404                 if (!acl_copy) {
 405                         err = -ENOMEM;
 406                         goto cleanup;
 407                 }
 408
 409                 need_acl = posix_acl_create_masq(acl_copy, &mode);
 410                 if (need_acl >= 0) {
 411                         if (mode != inode->i_mode) {
 412                                 inode->i_mode = mode;
 413                         }
 414
 415                         /* If we need an ACL.. */
 416                         if (need_acl > 0) {
 417                                 err = reiserfs_set_acl(th, inode,
 418                                                        ACL_TYPE_ACCESS,
 419                                                        acl_copy);
 420                                 if (err)
 421                                         goto cleanup_copy;
 422                         }
 423                 }
 424               cleanup_copy:
 425                 posix_acl_release(acl_copy);
 426               cleanup:
 427                 posix_acl_release(acl);
 428         } else {
 429               apply_umask:
 430                 /* no ACL, apply umask */
 431                 inode->i_mode &= ~current_umask();
 432         }
 433
 434         return err;
 435 }
 436
 437 /* This is used to cache the default acl before a new object is created.
 438  * The biggest reason for this is to get an idea of how many blocks will
 439  * actually be required for the create operation if we must inherit an ACL.
 440  * An ACL write can add up to 3 object creations and an additional file write
 441  * so we'd prefer not to reserve that many blocks in the journal if we can.
 442  * It also has the advantage of not loading the ACL with a transaction open,
 443  * this may seem silly, but if the owner of the directory is doing the
 444  * creation, the ACL may not be loaded since the permissions wouldn't require
 445  * it.
 446  * We return the number of blocks required for the transaction.
 447  */
 448 int reiserfs_cache_default_acl(struct inode *inode)
 449 {
 450         struct posix_acl *acl;
 451         int nblocks = 0;
 452
 453         if (IS_PRIVATE(inode))
 454                 return 0;
 455
 456         acl = reiserfs_get_acl(inode, ACL_TYPE_DEFAULT);
 457
 458         if (acl && !IS_ERR(acl)) {
 459                 int size = reiserfs_acl_size(acl->a_count);
 460
 461                 /* Other xattrs can be created during inode creation. We don't
 462                  * want to claim too many blocks, so we check to see if we
 463                  * we need to create the tree to the xattrs, and then we
 464                  * just want two files. */
 465                 nblocks = reiserfs_xattr_jcreate_nblocks(inode);
 466                 nblocks += JOURNAL_BLOCKS_PER_OBJECT(inode->i_sb);
 467
 468                 REISERFS_I(inode)->i_flags |= i_has_xattr_dir;
 469
 470                 /* We need to account for writes + bitmaps for two files */
 471                 nblocks += reiserfs_xattr_nblocks(inode, size) * 4;
 472                 posix_acl_release(acl);
 473         }
 474
 475         return nblocks;
 476 }
 477
 478 int reiserfs_acl_chmod(struct inode *inode)
 479 {
 480         struct posix_acl *acl, *clone;
 481         int error;
 482
 483         if (S_ISLNK(inode->i_mode))
 484                 return -EOPNOTSUPP;
 485
 486         if (get_inode_sd_version(inode) == STAT_DATA_V1 ||
 487             !reiserfs_posixacl(inode->i_sb)) {
 488                 return 0;
 489         }
 490
 491         acl = reiserfs_get_acl(inode, ACL_TYPE_ACCESS);
 492         if (!acl)
 493                 return 0;
 494         if (IS_ERR(acl))
 495                 return PTR_ERR(acl);
 496         clone = posix_acl_clone(acl, GFP_NOFS);
 497         posix_acl_release(acl);
 498         if (!clone)
 499                 return -ENOMEM;
 500         error = posix_acl_chmod_masq(clone, inode->i_mode);
 501         if (!error) {
 502                 struct reiserfs_transaction_handle th;
 503                 size_t size = reiserfs_xattr_nblocks(inode,
 504                                              reiserfs_acl_size(clone->a_count));
 505                 reiserfs_write_lock(inode->i_sb);
 506                 error = journal_begin(&th, inode->i_sb, size * 2);
 507                 if (!error) {
 508                         int error2;
 509                         error = reiserfs_set_acl(&th, inode, ACL_TYPE_ACCESS,
 510                                                  clone);
 511                         error2 = journal_end(&th, inode->i_sb, size * 2);
 512                         if (error2)
 513                                 error = error2;
 514                 }
 515                 reiserfs_write_unlock(inode->i_sb);
 516         }
 517         posix_acl_release(clone);
 518         return error;
 519 }
 520
 521 static int
 522 posix_acl_access_get(struct inode *inode, const char *name,
 523                      void *buffer, size_t size)
 524 {
 525         if (strlen(name) != sizeof(POSIX_ACL_XATTR_ACCESS) - 1)
 526                 return -EINVAL;
 527         return xattr_get_acl(inode, ACL_TYPE_ACCESS, buffer, size);
 528 }
 529
 530 static int
 531 posix_acl_access_set(struct inode *inode, const char *name,
 532                      const void *value, size_t size, int flags)
 533 {
 534         if (strlen(name) != sizeof(POSIX_ACL_XATTR_ACCESS) - 1)
 535                 return -EINVAL;
 536         return xattr_set_acl(inode, ACL_TYPE_ACCESS, value, size);
 537 }
 538
 539 static size_t posix_acl_access_list(struct inode *inode, char *list,
 540                                     size_t list_size, const char *name,
 541                                     size_t name_len)
 542 {
 543         const size_t size = sizeof(POSIX_ACL_XATTR_ACCESS);
 544         if (!reiserfs_posixacl(inode->i_sb))
 545                 return 0;
 546         if (list && size <= list_size)
 547                 memcpy(list, POSIX_ACL_XATTR_ACCESS, size);
 548         return size;
 549 }
 550
 551 struct xattr_handler reiserfs_posix_acl_access_handler = {
 552         .prefix = POSIX_ACL_XATTR_ACCESS,
 553         .get = posix_acl_access_get,
 554         .set = posix_acl_access_set,
 555         .list = posix_acl_access_list,
 556 };
 557
 558 static int
 559 posix_acl_default_get(struct inode *inode, const char *name,
 560                       void *buffer, size_t size)
 561 {
 562         if (strlen(name) != sizeof(POSIX_ACL_XATTR_DEFAULT) - 1)
 563                 return -EINVAL;
 564         return xattr_get_acl(inode, ACL_TYPE_DEFAULT, buffer, size);
 565 }
 566
 567 static int
 568 posix_acl_default_set(struct inode *inode, const char *name,
 569                       const void *value, size_t size, int flags)
 570 {
 571         if (strlen(name) != sizeof(POSIX_ACL_XATTR_DEFAULT) - 1)
 572                 return -EINVAL;
 573         return xattr_set_acl(inode, ACL_TYPE_DEFAULT, value, size);
 574 }
 575
 576 static size_t posix_acl_default_list(struct inode *inode, char *list,
 577                                      size_t list_size, const char *name,
 578                                      size_t name_len)
 579 {
 580         const size_t size = sizeof(POSIX_ACL_XATTR_DEFAULT);
 581         if (!reiserfs_posixacl(inode->i_sb))
 582                 return 0;
 583         if (list && size <= list_size)
 584                 memcpy(list, POSIX_ACL_XATTR_DEFAULT, size);
 585         return size;
 586 }
 587
 588 struct xattr_handler reiserfs_posix_acl_default_handler = {
 589         .prefix = POSIX_ACL_XATTR_DEFAULT,
 590         .get = posix_acl_default_get,
 591         .set = posix_acl_default_set,
 592         .list = posix_acl_default_list,
 593 };