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/xattr_acl.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, struct posix_acl *acl);
  13
  14 static int
  15 xattr_set_acl(struct inode *inode, int type, const void *value, size_t size)
  16 {
  17         struct posix_acl *acl;
  18         int error;
  19
  20         if (!reiserfs_posixacl(inode->i_sb))
  21                 return -EOPNOTSUPP;
  22         if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
  23                 return -EPERM;
  24
  25         if (value) {
  26                 acl = posix_acl_from_xattr(value, size);
  27                 if (IS_ERR(acl)) {
  28                         return PTR_ERR(acl);
  29                 } else if (acl) {
  30                         error = posix_acl_valid(acl);
  31                         if (error)
  32                                 goto release_and_out;
  33                 }
  34         } else
  35                 acl = NULL;
  36
  37         error = reiserfs_set_acl (inode, type, acl);
  38
  39 release_and_out:
  40         posix_acl_release(acl);
  41         return error;
  42 }
  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 /*
  67  * Convert from filesystem to in-memory representation.
  68  */
  69 static struct posix_acl *
  70 posix_acl_from_disk(const void *value, size_t size)
  71 {
  72         const char *end = (char *)value + size;
  73         int n, count;
  74         struct posix_acl *acl;
  75
  76         if (!value)
  77                 return NULL;
  78         if (size < sizeof(reiserfs_acl_header))
  79                  return ERR_PTR(-EINVAL);
  80         if (((reiserfs_acl_header *)value)->a_version !=
  81             cpu_to_le32(REISERFS_ACL_VERSION))
  82                 return ERR_PTR(-EINVAL);
  83         value = (char *)value + sizeof(reiserfs_acl_header);
  84         count = reiserfs_acl_count(size);
  85         if (count < 0)
  86                 return ERR_PTR(-EINVAL);
  87         if (count == 0)
  88                 return NULL;
  89         acl = posix_acl_alloc(count, GFP_NOFS);
  90         if (!acl)
  91                 return ERR_PTR(-ENOMEM);
  92         for (n=0; n < count; n++) {
  93                 reiserfs_acl_entry *entry =
  94                         (reiserfs_acl_entry *)value;
  95                 if ((char *)value + sizeof(reiserfs_acl_entry_short) > end)
  96                         goto fail;
  97                 acl->a_entries[n].e_tag  = le16_to_cpu(entry->e_tag);
  98                 acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
  99                 switch(acl->a_entries[n].e_tag) {
 100                         case ACL_USER_OBJ:
 101                         case ACL_GROUP_OBJ:
 102                         case ACL_MASK:
 103                         case ACL_OTHER:
 104                                 value = (char *)value +
 105                                         sizeof(reiserfs_acl_entry_short);
 106                                 acl->a_entries[n].e_id = ACL_UNDEFINED_ID;
 107                                 break;
 108
 109                         case ACL_USER:
 110                         case ACL_GROUP:
 111                                 value = (char *)value + sizeof(reiserfs_acl_entry);
 112                                 if ((char *)value > end)
 113                                         goto fail;
 114                                 acl->a_entries[n].e_id =
 115                                         le32_to_cpu(entry->e_id);
 116                                 break;
 117
 118                         default:
 119                                 goto fail;
 120                 }
 121         }
 122         if (value != end)
 123                 goto fail;
 124         return acl;
 125
 126 fail:
 127         posix_acl_release(acl);
 128         return ERR_PTR(-EINVAL);
 129 }
 130
 131 /*
 132  * Convert from in-memory to filesystem representation.
 133  */
 134 static void *
 135 posix_acl_to_disk(const struct posix_acl *acl, size_t *size)
 136 {
 137         reiserfs_acl_header *ext_acl;
 138         char *e;
 139         int n;
 140
 141         *size = reiserfs_acl_size(acl->a_count);
 142         ext_acl = (reiserfs_acl_header *)kmalloc(sizeof(reiserfs_acl_header) +
 143                 acl->a_count * sizeof(reiserfs_acl_entry), GFP_NOFS);
 144         if (!ext_acl)
 145                 return ERR_PTR(-ENOMEM);
 146         ext_acl->a_version = cpu_to_le32(REISERFS_ACL_VERSION);
 147         e = (char *)ext_acl + sizeof(reiserfs_acl_header);
 148         for (n=0; n < acl->a_count; n++) {
 149                 reiserfs_acl_entry *entry = (reiserfs_acl_entry *)e;
 150                 entry->e_tag  = cpu_to_le16(acl->a_entries[n].e_tag);
 151                 entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
 152                 switch(acl->a_entries[n].e_tag) {
 153                         case ACL_USER:
 154                         case ACL_GROUP:
 155                                 entry->e_id =
 156                                         cpu_to_le32(acl->a_entries[n].e_id);
 157                                 e += sizeof(reiserfs_acl_entry);
 158                                 break;
 159
 160                         case ACL_USER_OBJ:
 161                         case ACL_GROUP_OBJ:
 162                         case ACL_MASK:
 163                         case ACL_OTHER:
 164                                 e += sizeof(reiserfs_acl_entry_short);
 165                                 break;
 166
 167                         default:
 168                                 goto fail;
 169                 }
 170         }
 171         return (char *)ext_acl;
 172
 173 fail:
 174         kfree(ext_acl);
 175         return ERR_PTR(-EINVAL);
 176 }
 177
 178 /*
 179  * Inode operation get_posix_acl().
 180  *
 181  * inode->i_sem: down
 182  * BKL held [before 2.5.x]
 183  */
 184 struct posix_acl *
 185 reiserfs_get_acl(struct inode *inode, int type)
 186 {
 187         char *name, *value;
 188         struct posix_acl *acl, **p_acl;
 189         size_t size;
 190         int retval;
 191         struct reiserfs_inode_info *reiserfs_i = REISERFS_I(inode);
 192
 193         switch (type) {
 194             case ACL_TYPE_ACCESS:
 195                 name = XATTR_NAME_ACL_ACCESS;
 196                 p_acl = &reiserfs_i->i_acl_access;
 197                 break;
 198             case ACL_TYPE_DEFAULT:
 199                 name = XATTR_NAME_ACL_DEFAULT;
 200                 p_acl = &reiserfs_i->i_acl_default;
 201                 break;
 202             default:
 203                 return ERR_PTR (-EINVAL);
 204         }
 205
 206         if (IS_ERR (*p_acl)) {
 207             if (PTR_ERR (*p_acl) == -ENODATA)
 208                 return NULL;
 209         } else if (*p_acl != NULL)
 210             return posix_acl_dup (*p_acl);
 211
 212         size = reiserfs_xattr_get (inode, name, NULL, 0);
 213         if ((int)size < 0) {
 214             if (size == -ENODATA || size == -ENOSYS) {
 215                 *p_acl = ERR_PTR (-ENODATA);
 216                 return NULL;
 217             }
 218             return ERR_PTR (size);
 219         }
 220
 221         value = kmalloc (size, GFP_NOFS);
 222         if (!value)
 223             return ERR_PTR (-ENOMEM);
 224
 225         retval = reiserfs_xattr_get(inode, name, value, size);
 226         if (retval == -ENODATA || retval == -ENOSYS) {
 227                 /* This shouldn't actually happen as it should have
 228                    been caught above.. but just in case */
 229                 acl = NULL;
 230                 *p_acl = ERR_PTR (-ENODATA);
 231         } else if (retval < 0) {
 232                 acl = ERR_PTR(retval);
 233         } else {
 234                 acl = posix_acl_from_disk(value, retval);
 235                 *p_acl = posix_acl_dup (acl);
 236         }
 237
 238         kfree(value);
 239         return acl;
 240 }
 241
 242 /*
 243  * Inode operation set_posix_acl().
 244  *
 245  * inode->i_sem: down
 246  * BKL held [before 2.5.x]
 247  */
 248 static int
 249 reiserfs_set_acl(struct inode *inode, int type, struct posix_acl *acl)
 250 {
 251         char *name;
 252         void *value = NULL;
 253         struct posix_acl **p_acl;
 254         size_t size;
 255         int error;
 256         struct reiserfs_inode_info *reiserfs_i = REISERFS_I(inode);
 257
 258         if (S_ISLNK(inode->i_mode))
 259                 return -EOPNOTSUPP;
 260
 261         switch (type) {
 262             case ACL_TYPE_ACCESS:
 263                 name = XATTR_NAME_ACL_ACCESS;
 264                 p_acl = &reiserfs_i->i_acl_access;
 265                 if (acl) {
 266                     mode_t mode = inode->i_mode;
 267                     error = posix_acl_equiv_mode (acl, &mode);
 268                     if (error < 0)
 269                         return error;
 270                     else {
 271                         inode->i_mode = mode;
 272                         if (error == 0)
 273                             acl = NULL;
 274                     }
 275                 }
 276                 break;
 277             case ACL_TYPE_DEFAULT:
 278                 name = XATTR_NAME_ACL_DEFAULT;
 279                 p_acl = &reiserfs_i->i_acl_default;
 280                 if (!S_ISDIR (inode->i_mode))
 281                     return acl ? -EACCES : 0;
 282                 break;
 283             default:
 284                 return -EINVAL;
 285         }
 286
 287         if (acl) {
 288             value = posix_acl_to_disk(acl, &size);
 289             if (IS_ERR(value))
 290                 return (int)PTR_ERR(value);
 291             error = reiserfs_xattr_set(inode, name, value, size, 0);
 292         } else {
 293             error = reiserfs_xattr_del (inode, name);
 294             if (error == -ENODATA) {
 295                 /* This may seem odd here, but it means that the ACL was set
 296                  * with a value representable with mode bits. If there was
 297                  * an ACL before, reiserfs_xattr_del already dirtied the inode.
 298                  */
 299                 mark_inode_dirty (inode);
 300                 error = 0;
 301             }
 302         }
 303
 304         if (value)
 305                 kfree(value);
 306
 307         if (!error) {
 308             /* Release the old one */
 309             if (!IS_ERR (*p_acl) && *p_acl)
 310                 posix_acl_release (*p_acl);
 311
 312             if (acl == NULL)
 313                 *p_acl = ERR_PTR (-ENODATA);
 314             else
 315                 *p_acl = posix_acl_dup (acl);
 316         }
 317
 318         return error;
 319 }
 320
 321 /* dir->i_sem: down,
 322  * inode is new and not released into the wild yet */
 323 int
 324 reiserfs_inherit_default_acl (struct inode *dir, struct dentry *dentry, struct inode *inode)
 325 {
 326     struct posix_acl *acl;
 327     int err = 0;
 328
 329     /* ACLs only get applied to files and directories */
 330     if (S_ISLNK (inode->i_mode))
 331         return 0;
 332
 333     /* ACLs can only be used on "new" objects, so if it's an old object
 334      * there is nothing to inherit from */
 335     if (get_inode_sd_version (dir) == STAT_DATA_V1)
 336         goto apply_umask;
 337
 338     /* Don't apply ACLs to objects in the .reiserfs_priv tree.. This
 339      * would be useless since permissions are ignored, and a pain because
 340      * it introduces locking cycles */
 341     if (is_reiserfs_priv_object (dir)) {
 342         reiserfs_mark_inode_private (inode);
 343         goto apply_umask;
 344     }
 345
 346     acl = reiserfs_get_acl (dir, ACL_TYPE_DEFAULT);
 347     if (IS_ERR (acl)) {
 348         if (PTR_ERR (acl) == -ENODATA)
 349             goto apply_umask;
 350         return PTR_ERR (acl);
 351     }
 352
 353     if (acl) {
 354         struct posix_acl *acl_copy;
 355         mode_t mode = inode->i_mode;
 356         int need_acl;
 357
 358         /* Copy the default ACL to the default ACL of a new directory */
 359         if (S_ISDIR (inode->i_mode)) {
 360             err = reiserfs_set_acl (inode, ACL_TYPE_DEFAULT, 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
 374         need_acl = posix_acl_create_masq (acl_copy, &mode);
 375         if (need_acl >= 0) {
 376             if (mode != inode->i_mode) {
 377                 inode->i_mode = mode;
 378             }
 379
 380             /* If we need an ACL.. */
 381             if (need_acl > 0) {
 382                 err = reiserfs_set_acl (inode, ACL_TYPE_ACCESS, acl_copy);
 383                 if (err)
 384                     goto cleanup_copy;
 385             }
 386         }
 387 cleanup_copy:
 388         posix_acl_release (acl_copy);
 389 cleanup:
 390         posix_acl_release (acl);
 391     } else {
 392 apply_umask:
 393         /* no ACL, apply umask */
 394         inode->i_mode &= ~current->fs->umask;
 395     }
 396
 397     return err;
 398 }
 399
 400 /* Looks up and caches the result of the default ACL.
 401  * We do this so that we don't need to carry the xattr_sem into
 402  * reiserfs_new_inode if we don't need to */
 403 int
 404 reiserfs_cache_default_acl (struct inode *inode)
 405 {
 406     int ret = 0;
 407     if (reiserfs_posixacl (inode->i_sb) &&
 408         !is_reiserfs_priv_object (inode)) {
 409         struct posix_acl *acl;
 410         reiserfs_read_lock_xattr_i (inode);
 411         reiserfs_read_lock_xattrs (inode->i_sb);
 412         acl = reiserfs_get_acl (inode, ACL_TYPE_DEFAULT);
 413         reiserfs_read_unlock_xattrs (inode->i_sb);
 414         reiserfs_read_unlock_xattr_i (inode);
 415         ret = acl ? 1 : 0;
 416         posix_acl_release (acl);
 417     }
 418
 419     return ret;
 420 }
 421
 422 int
 423 reiserfs_acl_chmod (struct inode *inode)
 424 {
 425         struct posix_acl *acl, *clone;
 426         int error;
 427
 428         if (S_ISLNK(inode->i_mode))
 429                 return -EOPNOTSUPP;
 430
 431         if (get_inode_sd_version (inode) == STAT_DATA_V1 ||
 432             !reiserfs_posixacl(inode->i_sb))
 433         {
 434             return 0;
 435         }
 436
 437         reiserfs_read_lock_xattrs (inode->i_sb);
 438         acl = reiserfs_get_acl(inode, ACL_TYPE_ACCESS);
 439         reiserfs_read_unlock_xattrs (inode->i_sb);
 440         if (!acl)
 441                 return 0;
 442         if (IS_ERR(acl))
 443                 return PTR_ERR(acl);
 444         clone = posix_acl_clone(acl, GFP_NOFS);
 445         posix_acl_release(acl);
 446         if (!clone)
 447                 return -ENOMEM;
 448         error = posix_acl_chmod_masq(clone, inode->i_mode);
 449         if (!error) {
 450                 int lock = !has_xattr_dir (inode);
 451                 reiserfs_write_lock_xattr_i (inode);
 452                 if (lock)
 453                     reiserfs_write_lock_xattrs (inode->i_sb);
 454                 else
 455                     reiserfs_read_lock_xattrs (inode->i_sb);
 456                 error = reiserfs_set_acl(inode, ACL_TYPE_ACCESS, clone);
 457                 if (lock)
 458                     reiserfs_write_unlock_xattrs (inode->i_sb);
 459                 else
 460                     reiserfs_read_unlock_xattrs (inode->i_sb);
 461                 reiserfs_write_unlock_xattr_i (inode);
 462         }
 463         posix_acl_release(clone);
 464         return error;
 465 }
 466
 467 static int
 468 posix_acl_access_get(struct inode *inode, const char *name,
 469                           void *buffer, size_t size)
 470 {
 471         if (strlen(name) != sizeof(XATTR_NAME_ACL_ACCESS)-1)
 472                 return -EINVAL;
 473         return xattr_get_acl(inode, ACL_TYPE_ACCESS, buffer, size);
 474 }
 475
 476 static int
 477 posix_acl_access_set(struct inode *inode, const char *name,
 478                           const void *value, size_t size, int flags)
 479 {
 480         if (strlen(name) != sizeof(XATTR_NAME_ACL_ACCESS)-1)
 481                 return -EINVAL;
 482         return xattr_set_acl(inode, ACL_TYPE_ACCESS, value, size);
 483 }
 484
 485 static int
 486 posix_acl_access_del (struct inode *inode, const char *name)
 487 {
 488     struct reiserfs_inode_info *reiserfs_i = REISERFS_I(inode);
 489     struct posix_acl **acl = &reiserfs_i->i_acl_access;
 490     if (strlen(name) != sizeof(XATTR_NAME_ACL_ACCESS)-1)
 491         return -EINVAL;
 492     if (!IS_ERR (*acl) && *acl) {
 493         posix_acl_release (*acl);
 494         *acl = ERR_PTR (-ENODATA);
 495     }
 496
 497     return 0;
 498 }
 499
 500 static int
 501 posix_acl_access_list (struct inode *inode, const char *name, int namelen, char *out)
 502 {
 503     int len = namelen;
 504     if (!reiserfs_posixacl (inode->i_sb))
 505         return 0;
 506     if (out)
 507         memcpy (out, name, len);
 508
 509     return len;
 510 }
 511
 512 struct reiserfs_xattr_handler posix_acl_access_handler = {
 513         .prefix = XATTR_NAME_ACL_ACCESS,
 514         .get = posix_acl_access_get,
 515         .set = posix_acl_access_set,
 516         .del = posix_acl_access_del,
 517         .list = posix_acl_access_list,
 518 };
 519
 520 static int
 521 posix_acl_default_get (struct inode *inode, const char *name,
 522                            void *buffer, size_t size)
 523 {
 524         if (strlen(name) != sizeof(XATTR_NAME_ACL_DEFAULT)-1)
 525                 return -EINVAL;
 526         return xattr_get_acl(inode, ACL_TYPE_DEFAULT, buffer, size);
 527 }
 528
 529 static int
 530 posix_acl_default_set(struct inode *inode, const char *name,
 531                            const void *value, size_t size, int flags)
 532 {
 533         if (strlen(name) != sizeof(XATTR_NAME_ACL_DEFAULT)-1)
 534                 return -EINVAL;
 535         return xattr_set_acl(inode, ACL_TYPE_DEFAULT, value, size);
 536 }
 537
 538 static int
 539 posix_acl_default_del (struct inode *inode, const char *name)
 540 {
 541     struct reiserfs_inode_info *reiserfs_i = REISERFS_I(inode);
 542     struct posix_acl **acl = &reiserfs_i->i_acl_default;
 543     if (strlen(name) != sizeof(XATTR_NAME_ACL_DEFAULT)-1)
 544         return -EINVAL;
 545     if (!IS_ERR (*acl) && *acl) {
 546         posix_acl_release (*acl);
 547         *acl = ERR_PTR (-ENODATA);
 548     }
 549
 550     return 0;
 551 }
 552
 553 static int
 554 posix_acl_default_list (struct inode *inode, const char *name, int namelen, char *out)
 555 {
 556     int len = namelen;
 557     if (!reiserfs_posixacl (inode->i_sb))
 558         return 0;
 559     if (out)
 560         memcpy (out, name, len);
 561
 562     return len;
 563 }
 564
 565 struct reiserfs_xattr_handler posix_acl_default_handler = {
 566         .prefix = XATTR_NAME_ACL_DEFAULT,
 567         .get = posix_acl_default_get,
 568         .set = posix_acl_default_set,
 569         .del = posix_acl_default_del,
 570         .list = posix_acl_default_list,
 571 };