fs/reiserfs/xattr_acl.c

   1 #include <linux/fs.h>
   2 #include <linux/posix_acl.h>
   3 #include <linux/reiserfs_fs.h>
   4 #include <linux/errno.h>
   5 #include <linux/pagemap.h>
   6 #include <linux/xattr.h>
   7 #include <linux/posix_acl_xattr.h>
   8 #include <linux/reiserfs_xattr.h>
   9 #include <linux/reiserfs_acl.h>
  10 #include <asm/uaccess.h>
  11
  12 static int reiserfs_set_acl(struct inode *inode, int type,
  13                             struct posix_acl *acl);
  14
  15 static int
  16 xattr_set_acl(struct inode *inode, int type, const void *value, size_t size)
  17 {
  18         struct posix_acl *acl;
  19         int error;
  20
  21         if (!reiserfs_posixacl(inode->i_sb))
  22                 return -EOPNOTSUPP;
  23         if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
  24                 return -EPERM;
  25
  26         if (value) {
  27                 acl = posix_acl_from_xattr(value, size);
  28                 if (IS_ERR(acl)) {
  29                         return PTR_ERR(acl);
  30                 } else if (acl) {
  31                         error = posix_acl_valid(acl);
  32                         if (error)
  33                                 goto release_and_out;
  34                 }
  35         } else
  36                 acl = NULL;
  37
  38         error = reiserfs_set_acl(inode, type, acl);
  39
  40       release_and_out:
  41         posix_acl_release(acl);
  42         return error;
  43 }
  44
  45 static int
  46 xattr_get_acl(struct inode *inode, int type, void *buffer, size_t size)
  47 {
  48         struct posix_acl *acl;
  49         int error;
  50
  51         if (!reiserfs_posixacl(inode->i_sb))
  52                 return -EOPNOTSUPP;
  53
  54         acl = reiserfs_get_acl(inode, type);
  55         if (IS_ERR(acl))
  56                 return PTR_ERR(acl);
  57         if (acl == NULL)
  58                 return -ENODATA;
  59         error = posix_acl_to_xattr(acl, buffer, size);
  60         posix_acl_release(acl);
  61
  62         return error;
  63 }
  64
  65 /*
  66  * Convert from filesystem to in-memory representation.
  67  */
  68 static struct posix_acl *posix_acl_from_disk(const void *value, size_t size)
  69 {
  70         const char *end = (char *)value + size;
  71         int n, count;
  72         struct posix_acl *acl;
  73
  74         if (!value)
  75                 return NULL;
  76         if (size < sizeof(reiserfs_acl_header))
  77                 return ERR_PTR(-EINVAL);
  78         if (((reiserfs_acl_header *) value)->a_version !=
  79             cpu_to_le32(REISERFS_ACL_VERSION))
  80                 return ERR_PTR(-EINVAL);
  81         value = (char *)value + sizeof(reiserfs_acl_header);
  82         count = reiserfs_acl_count(size);
  83         if (count < 0)
  84                 return ERR_PTR(-EINVAL);
  85         if (count == 0)
  86                 return NULL;
  87         acl = posix_acl_alloc(count, GFP_NOFS);
  88         if (!acl)
  89                 return ERR_PTR(-ENOMEM);
  90         for (n = 0; n < count; n++) {
  91                 reiserfs_acl_entry *entry = (reiserfs_acl_entry *) value;
  92                 if ((char *)value + sizeof(reiserfs_acl_entry_short) > end)
  93                         goto fail;
  94                 acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag);
  95                 acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
  96                 switch (acl->a_entries[n].e_tag) {
  97                 case ACL_USER_OBJ:
  98                 case ACL_GROUP_OBJ:
  99                 case ACL_MASK:
 100                 case ACL_OTHER:
 101                         value = (char *)value +
 102                             sizeof(reiserfs_acl_entry_short);
 103                         acl->a_entries[n].e_id = ACL_UNDEFINED_ID;
 104                         break;
 105
 106                 case ACL_USER:
 107                 case ACL_GROUP:
 108                         value = (char *)value + sizeof(reiserfs_acl_entry);
 109                         if ((char *)value > end)
 110                                 goto fail;
 111                         acl->a_entries[n].e_id = le32_to_cpu(entry->e_id);
 112                         break;
 113
 114                 default:
 115                         goto fail;
 116                 }
 117         }
 118         if (value != end)
 119                 goto fail;
 120         return acl;
 121
 122       fail:
 123         posix_acl_release(acl);
 124         return ERR_PTR(-EINVAL);
 125 }
 126
 127 /*
 128  * Convert from in-memory to filesystem representation.
 129  */
 130 static void *posix_acl_to_disk(const struct posix_acl *acl, size_t * size)
 131 {
 132         reiserfs_acl_header *ext_acl;
 133         char *e;
 134         int n;
 135
 136         *size = reiserfs_acl_size(acl->a_count);
 137         ext_acl = (reiserfs_acl_header *) kmalloc(sizeof(reiserfs_acl_header) +
 138                                                   acl->a_count *
 139                                                   sizeof(reiserfs_acl_entry),
 140                                                   GFP_NOFS);
 141         if (!ext_acl)
 142                 return ERR_PTR(-ENOMEM);
 143         ext_acl->a_version = cpu_to_le32(REISERFS_ACL_VERSION);
 144         e = (char *)ext_acl + sizeof(reiserfs_acl_header);
 145         for (n = 0; n < acl->a_count; n++) {
 146                 reiserfs_acl_entry *entry = (reiserfs_acl_entry *) e;
 147                 entry->e_tag = cpu_to_le16(acl->a_entries[n].e_tag);
 148                 entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
 149                 switch (acl->a_entries[n].e_tag) {
 150                 case ACL_USER:
 151                 case ACL_GROUP:
 152                         entry->e_id = cpu_to_le32(acl->a_entries[n].e_id);
 153                         e += sizeof(reiserfs_acl_entry);
 154                         break;
 155
 156                 case ACL_USER_OBJ:
 157                 case ACL_GROUP_OBJ:
 158                 case ACL_MASK:
 159                 case ACL_OTHER:
 160                         e += sizeof(reiserfs_acl_entry_short);
 161                         break;
 162
 163                 default:
 164                         goto fail;
 165                 }
 166         }
 167         return (char *)ext_acl;
 168
 169       fail:
 170         kfree(ext_acl);
 171         return ERR_PTR(-EINVAL);
 172 }
 173
 174 /*
 175  * Inode operation get_posix_acl().
 176  *
 177  * inode->i_sem: down
 178  * BKL held [before 2.5.x]
 179  */
 180 struct posix_acl *reiserfs_get_acl(struct inode *inode, int type)
 181 {
 182         char *name, *value;
 183         struct posix_acl *acl, **p_acl;
 184         size_t size;
 185         int retval;
 186         struct reiserfs_inode_info *reiserfs_i = REISERFS_I(inode);
 187
 188         switch (type) {
 189         case ACL_TYPE_ACCESS:
 190                 name = POSIX_ACL_XATTR_ACCESS;
 191                 p_acl = &reiserfs_i->i_acl_access;
 192                 break;
 193         case ACL_TYPE_DEFAULT:
 194                 name = POSIX_ACL_XATTR_DEFAULT;
 195                 p_acl = &reiserfs_i->i_acl_default;
 196                 break;
 197         default:
 198                 return ERR_PTR(-EINVAL);
 199         }
 200
 201         if (IS_ERR(*p_acl)) {
 202                 if (PTR_ERR(*p_acl) == -ENODATA)
 203                         return NULL;
 204         } else if (*p_acl != NULL)
 205                 return posix_acl_dup(*p_acl);
 206
 207         size = reiserfs_xattr_get(inode, name, NULL, 0);
 208         if ((int)size < 0) {
 209                 if (size == -ENODATA || size == -ENOSYS) {
 210                         *p_acl = ERR_PTR(-ENODATA);
 211                         return NULL;
 212                 }
 213                 return ERR_PTR(size);
 214         }
 215
 216         value = kmalloc(size, GFP_NOFS);
 217         if (!value)
 218                 return ERR_PTR(-ENOMEM);
 219
 220         retval = reiserfs_xattr_get(inode, name, value, size);
 221         if (retval == -ENODATA || retval == -ENOSYS) {
 222                 /* This shouldn't actually happen as it should have
 223                    been caught above.. but just in case */
 224                 acl = NULL;
 225                 *p_acl = ERR_PTR(-ENODATA);
 226         } else if (retval < 0) {
 227                 acl = ERR_PTR(retval);
 228         } else {
 229                 acl = posix_acl_from_disk(value, retval);
 230                 *p_acl = posix_acl_dup(acl);
 231         }
 232
 233         kfree(value);
 234         return acl;
 235 }
 236
 237 /*
 238  * Inode operation set_posix_acl().
 239  *
 240  * inode->i_sem: down
 241  * BKL held [before 2.5.x]
 242  */
 243 static int
 244 reiserfs_set_acl(struct inode *inode, int type, struct posix_acl *acl)
 245 {
 246         char *name;
 247         void *value = NULL;
 248         struct posix_acl **p_acl;
 249         size_t size;
 250         int error;
 251         struct reiserfs_inode_info *reiserfs_i = REISERFS_I(inode);
 252
 253         if (S_ISLNK(inode->i_mode))
 254                 return -EOPNOTSUPP;
 255
 256         switch (type) {
 257         case ACL_TYPE_ACCESS:
 258                 name = POSIX_ACL_XATTR_ACCESS;
 259                 p_acl = &reiserfs_i->i_acl_access;
 260                 if (acl) {
 261                         mode_t mode = inode->i_mode;
 262                         error = posix_acl_equiv_mode(acl, &mode);
 263                         if (error < 0)
 264                                 return error;
 265                         else {
 266                                 inode->i_mode = mode;
 267                                 if (error == 0)
 268                                         acl = NULL;
 269                         }
 270                 }
 271                 break;
 272         case ACL_TYPE_DEFAULT:
 273                 name = POSIX_ACL_XATTR_DEFAULT;
 274                 p_acl = &reiserfs_i->i_acl_default;
 275                 if (!S_ISDIR(inode->i_mode))
 276                         return acl ? -EACCES : 0;
 277                 break;
 278         default:
 279                 return -EINVAL;
 280         }
 281
 282         if (acl) {
 283                 value = posix_acl_to_disk(acl, &size);
 284                 if (IS_ERR(value))
 285                         return (int)PTR_ERR(value);
 286                 error = reiserfs_xattr_set(inode, name, value, size, 0);
 287         } else {
 288                 error = reiserfs_xattr_del(inode, name);
 289                 if (error == -ENODATA) {
 290                         /* This may seem odd here, but it means that the ACL was set
 291                          * with a value representable with mode bits. If there was
 292                          * an ACL before, reiserfs_xattr_del already dirtied the inode.
 293                          */
 294                         mark_inode_dirty(inode);
 295                         error = 0;
 296                 }
 297         }
 298
 299         kfree(value);
 300
 301         if (!error) {
 302                 /* Release the old one */
 303                 if (!IS_ERR(*p_acl) && *p_acl)
 304                         posix_acl_release(*p_acl);
 305
 306                 if (acl == NULL)
 307                         *p_acl = ERR_PTR(-ENODATA);
 308                 else
 309                         *p_acl = posix_acl_dup(acl);
 310         }
 311
 312         return error;
 313 }
 314
 315 /* dir->i_sem: down,
 316  * inode is new and not released into the wild yet */
 317 int
 318 reiserfs_inherit_default_acl(struct inode *dir, struct dentry *dentry,
 319                              struct inode *inode)
 320 {
 321         struct posix_acl *acl;
 322         int err = 0;
 323
 324         /* ACLs only get applied to files and directories */
 325         if (S_ISLNK(inode->i_mode))
 326                 return 0;
 327
 328         /* ACLs can only be used on "new" objects, so if it's an old object
 329          * there is nothing to inherit from */
 330         if (get_inode_sd_version(dir) == STAT_DATA_V1)
 331                 goto apply_umask;
 332
 333         /* Don't apply ACLs to objects in the .reiserfs_priv tree.. This
 334          * would be useless since permissions are ignored, and a pain because
 335          * it introduces locking cycles */
 336         if (is_reiserfs_priv_object(dir)) {
 337                 reiserfs_mark_inode_private(inode);
 338                 goto apply_umask;
 339         }
 340
 341         acl = reiserfs_get_acl(dir, ACL_TYPE_DEFAULT);
 342         if (IS_ERR(acl)) {
 343                 if (PTR_ERR(acl) == -ENODATA)
 344                         goto apply_umask;
 345                 return PTR_ERR(acl);
 346         }
 347
 348         if (acl) {
 349                 struct posix_acl *acl_copy;
 350                 mode_t mode = inode->i_mode;
 351                 int need_acl;
 352
 353                 /* Copy the default ACL to the default ACL of a new directory */
 354                 if (S_ISDIR(inode->i_mode)) {
 355                         err = reiserfs_set_acl(inode, ACL_TYPE_DEFAULT, acl);
 356                         if (err)
 357                                 goto cleanup;
 358                 }
 359
 360                 /* Now we reconcile the new ACL and the mode,
 361                    potentially modifying both */
 362                 acl_copy = posix_acl_clone(acl, GFP_NOFS);
 363                 if (!acl_copy) {
 364                         err = -ENOMEM;
 365                         goto cleanup;
 366                 }
 367
 368                 need_acl = posix_acl_create_masq(acl_copy, &mode);
 369                 if (need_acl >= 0) {
 370                         if (mode != inode->i_mode) {
 371                                 inode->i_mode = mode;
 372                         }
 373
 374                         /* If we need an ACL.. */
 375                         if (need_acl > 0) {
 376                                 err =
 377                                     reiserfs_set_acl(inode, ACL_TYPE_ACCESS,
 378                                                      acl_copy);
 379                                 if (err)
 380                                         goto cleanup_copy;
 381                         }
 382                 }
 383               cleanup_copy:
 384                 posix_acl_release(acl_copy);
 385               cleanup:
 386                 posix_acl_release(acl);
 387         } else {
 388               apply_umask:
 389                 /* no ACL, apply umask */
 390                 inode->i_mode &= ~current->fs->umask;
 391         }
 392
 393         return err;
 394 }
 395
 396 /* Looks up and caches the result of the default ACL.
 397  * We do this so that we don't need to carry the xattr_sem into
 398  * reiserfs_new_inode if we don't need to */
 399 int reiserfs_cache_default_acl(struct inode *inode)
 400 {
 401         int ret = 0;
 402         if (reiserfs_posixacl(inode->i_sb) && !is_reiserfs_priv_object(inode)) {
 403                 struct posix_acl *acl;
 404                 reiserfs_read_lock_xattr_i(inode);
 405                 reiserfs_read_lock_xattrs(inode->i_sb);
 406                 acl = reiserfs_get_acl(inode, ACL_TYPE_DEFAULT);
 407                 reiserfs_read_unlock_xattrs(inode->i_sb);
 408                 reiserfs_read_unlock_xattr_i(inode);
 409                 ret = acl ? 1 : 0;
 410                 posix_acl_release(acl);
 411         }
 412
 413         return ret;
 414 }
 415
 416 int reiserfs_acl_chmod(struct inode *inode)
 417 {
 418         struct posix_acl *acl, *clone;
 419         int error;
 420
 421         if (S_ISLNK(inode->i_mode))
 422                 return -EOPNOTSUPP;
 423
 424         if (get_inode_sd_version(inode) == STAT_DATA_V1 ||
 425             !reiserfs_posixacl(inode->i_sb)) {
 426                 return 0;
 427         }
 428
 429         reiserfs_read_lock_xattrs(inode->i_sb);
 430         acl = reiserfs_get_acl(inode, ACL_TYPE_ACCESS);
 431         reiserfs_read_unlock_xattrs(inode->i_sb);
 432         if (!acl)
 433                 return 0;
 434         if (IS_ERR(acl))
 435                 return PTR_ERR(acl);
 436         clone = posix_acl_clone(acl, GFP_NOFS);
 437         posix_acl_release(acl);
 438         if (!clone)
 439                 return -ENOMEM;
 440         error = posix_acl_chmod_masq(clone, inode->i_mode);
 441         if (!error) {
 442                 int lock = !has_xattr_dir(inode);
 443                 reiserfs_write_lock_xattr_i(inode);
 444                 if (lock)
 445                         reiserfs_write_lock_xattrs(inode->i_sb);
 446                 else
 447                         reiserfs_read_lock_xattrs(inode->i_sb);
 448                 error = reiserfs_set_acl(inode, ACL_TYPE_ACCESS, clone);
 449                 if (lock)
 450                         reiserfs_write_unlock_xattrs(inode->i_sb);
 451                 else
 452                         reiserfs_read_unlock_xattrs(inode->i_sb);
 453                 reiserfs_write_unlock_xattr_i(inode);
 454         }
 455         posix_acl_release(clone);
 456         return error;
 457 }
 458
 459 static int
 460 posix_acl_access_get(struct inode *inode, const char *name,
 461                      void *buffer, size_t size)
 462 {
 463         if (strlen(name) != sizeof(POSIX_ACL_XATTR_ACCESS) - 1)
 464                 return -EINVAL;
 465         return xattr_get_acl(inode, ACL_TYPE_ACCESS, buffer, size);
 466 }
 467
 468 static int
 469 posix_acl_access_set(struct inode *inode, const char *name,
 470                      const void *value, size_t size, int flags)
 471 {
 472         if (strlen(name) != sizeof(POSIX_ACL_XATTR_ACCESS) - 1)
 473                 return -EINVAL;
 474         return xattr_set_acl(inode, ACL_TYPE_ACCESS, value, size);
 475 }
 476
 477 static int posix_acl_access_del(struct inode *inode, const char *name)
 478 {
 479         struct reiserfs_inode_info *reiserfs_i = REISERFS_I(inode);
 480         struct posix_acl **acl = &reiserfs_i->i_acl_access;
 481         if (strlen(name) != sizeof(POSIX_ACL_XATTR_ACCESS) - 1)
 482                 return -EINVAL;
 483         if (!IS_ERR(*acl) && *acl) {
 484                 posix_acl_release(*acl);
 485                 *acl = ERR_PTR(-ENODATA);
 486         }
 487
 488         return 0;
 489 }
 490
 491 static int
 492 posix_acl_access_list(struct inode *inode, const char *name, int namelen,
 493                       char *out)
 494 {
 495         int len = namelen;
 496         if (!reiserfs_posixacl(inode->i_sb))
 497                 return 0;
 498         if (out)
 499                 memcpy(out, name, len);
 500
 501         return len;
 502 }
 503
 504 struct reiserfs_xattr_handler posix_acl_access_handler = {
 505         .prefix = POSIX_ACL_XATTR_ACCESS,
 506         .get = posix_acl_access_get,
 507         .set = posix_acl_access_set,
 508         .del = posix_acl_access_del,
 509         .list = posix_acl_access_list,
 510 };
 511
 512 static int
 513 posix_acl_default_get(struct inode *inode, const char *name,
 514                       void *buffer, size_t size)
 515 {
 516         if (strlen(name) != sizeof(POSIX_ACL_XATTR_DEFAULT) - 1)
 517                 return -EINVAL;
 518         return xattr_get_acl(inode, ACL_TYPE_DEFAULT, buffer, size);
 519 }
 520
 521 static int
 522 posix_acl_default_set(struct inode *inode, const char *name,
 523                       const void *value, size_t size, int flags)
 524 {
 525         if (strlen(name) != sizeof(POSIX_ACL_XATTR_DEFAULT) - 1)
 526                 return -EINVAL;
 527         return xattr_set_acl(inode, ACL_TYPE_DEFAULT, value, size);
 528 }
 529
 530 static int posix_acl_default_del(struct inode *inode, const char *name)
 531 {
 532         struct reiserfs_inode_info *reiserfs_i = REISERFS_I(inode);
 533         struct posix_acl **acl = &reiserfs_i->i_acl_default;
 534         if (strlen(name) != sizeof(POSIX_ACL_XATTR_DEFAULT) - 1)
 535                 return -EINVAL;
 536         if (!IS_ERR(*acl) && *acl) {
 537                 posix_acl_release(*acl);
 538                 *acl = ERR_PTR(-ENODATA);
 539         }
 540
 541         return 0;
 542 }
 543
 544 static int
 545 posix_acl_default_list(struct inode *inode, const char *name, int namelen,
 546                        char *out)
 547 {
 548         int len = namelen;
 549         if (!reiserfs_posixacl(inode->i_sb))
 550                 return 0;
 551         if (out)
 552                 memcpy(out, name, len);
 553
 554         return len;
 555 }
 556
 557 struct reiserfs_xattr_handler posix_acl_default_handler = {
 558         .prefix = POSIX_ACL_XATTR_DEFAULT,
 559         .get = posix_acl_default_get,
 560         .set = posix_acl_default_set,
 561         .del = posix_acl_default_del,
 562         .list = posix_acl_default_list,
 563 };