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