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 inode *inode, int type,
  14                             struct posix_acl *acl);
  15
  16 static int
  17 xattr_set_acl(struct inode *inode, int type, const void *value, size_t size)
  18 {
  19         struct posix_acl *acl;
  20         int error;
  21
  22         if (!reiserfs_posixacl(inode->i_sb))
  23                 return -EOPNOTSUPP;
  24         if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
  25                 return -EPERM;
  26
  27         if (value) {
  28                 acl = posix_acl_from_xattr(value, size);
  29                 if (IS_ERR(acl)) {
  30                         return PTR_ERR(acl);
  31                 } else if (acl) {
  32                         error = posix_acl_valid(acl);
  33                         if (error)
  34                                 goto release_and_out;
  35                 }
  36         } else
  37                 acl = NULL;
  38
  39         error = reiserfs_set_acl(inode, type, acl);
  40
  41       release_and_out:
  42         posix_acl_release(acl);
  43         return error;
  44 }
  45
  46 static int
  47 xattr_get_acl(struct inode *inode, int type, void *buffer, size_t size)
  48 {
  49         struct posix_acl *acl;
  50         int error;
  51
  52         if (!reiserfs_posixacl(inode->i_sb))
  53                 return -EOPNOTSUPP;
  54
  55         acl = reiserfs_get_acl(inode, type);
  56         if (IS_ERR(acl))
  57                 return PTR_ERR(acl);
  58         if (acl == NULL)
  59                 return -ENODATA;
  60         error = posix_acl_to_xattr(acl, buffer, size);
  61         posix_acl_release(acl);
  62
  63         return error;
  64 }
  65
  66 /*
  67  * Convert from filesystem to in-memory representation.
  68  */
  69 static struct posix_acl *posix_acl_from_disk(const void *value, size_t size)
  70 {
  71         const char *end = (char *)value + size;
  72         int n, count;
  73         struct posix_acl *acl;
  74
  75         if (!value)
  76                 return NULL;
  77         if (size < sizeof(reiserfs_acl_header))
  78                 return ERR_PTR(-EINVAL);
  79         if (((reiserfs_acl_header *) value)->a_version !=
  80             cpu_to_le32(REISERFS_ACL_VERSION))
  81                 return ERR_PTR(-EINVAL);
  82         value = (char *)value + sizeof(reiserfs_acl_header);
  83         count = reiserfs_acl_count(size);
  84         if (count < 0)
  85                 return ERR_PTR(-EINVAL);
  86         if (count == 0)
  87                 return NULL;
  88         acl = posix_acl_alloc(count, GFP_NOFS);
  89         if (!acl)
  90                 return ERR_PTR(-ENOMEM);
  91         for (n = 0; n < count; n++) {
  92                 reiserfs_acl_entry *entry = (reiserfs_acl_entry *) value;
  93                 if ((char *)value + sizeof(reiserfs_acl_entry_short) > end)
  94                         goto fail;
  95                 acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag);
  96                 acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
  97                 switch (acl->a_entries[n].e_tag) {
  98                 case ACL_USER_OBJ:
  99                 case ACL_GROUP_OBJ:
 100                 case ACL_MASK:
 101                 case ACL_OTHER:
 102                         value = (char *)value +
 103                             sizeof(reiserfs_acl_entry_short);
 104                         acl->a_entries[n].e_id = ACL_UNDEFINED_ID;
 105                         break;
 106
 107                 case ACL_USER:
 108                 case ACL_GROUP:
 109                         value = (char *)value + sizeof(reiserfs_acl_entry);
 110                         if ((char *)value > end)
 111                                 goto fail;
 112                         acl->a_entries[n].e_id = le32_to_cpu(entry->e_id);
 113                         break;
 114
 115                 default:
 116                         goto fail;
 117                 }
 118         }
 119         if (value != end)
 120                 goto fail;
 121         return acl;
 122
 123       fail:
 124         posix_acl_release(acl);
 125         return ERR_PTR(-EINVAL);
 126 }
 127
 128 /*
 129  * Convert from in-memory to filesystem representation.
 130  */
 131 static void *posix_acl_to_disk(const struct posix_acl *acl, size_t * size)
 132 {
 133         reiserfs_acl_header *ext_acl;
 134         char *e;
 135         int n;
 136
 137         *size = reiserfs_acl_size(acl->a_count);
 138         ext_acl = (reiserfs_acl_header *) kmalloc(sizeof(reiserfs_acl_header) +
 139                                                   acl->a_count *
 140                                                   sizeof(reiserfs_acl_entry),
 141                                                   GFP_NOFS);
 142         if (!ext_acl)
 143                 return ERR_PTR(-ENOMEM);
 144         ext_acl->a_version = cpu_to_le32(REISERFS_ACL_VERSION);
 145         e = (char *)ext_acl + sizeof(reiserfs_acl_header);
 146         for (n = 0; n < acl->a_count; n++) {
 147                 reiserfs_acl_entry *entry = (reiserfs_acl_entry *) e;
 148                 entry->e_tag = cpu_to_le16(acl->a_entries[n].e_tag);
 149                 entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
 150                 switch (acl->a_entries[n].e_tag) {
 151                 case ACL_USER:
 152                 case ACL_GROUP:
 153                         entry->e_id = cpu_to_le32(acl->a_entries[n].e_id);
 154                         e += sizeof(reiserfs_acl_entry);
 155                         break;
 156
 157                 case ACL_USER_OBJ:
 158                 case ACL_GROUP_OBJ:
 159                 case ACL_MASK:
 160                 case ACL_OTHER:
 161                         e += sizeof(reiserfs_acl_entry_short);
 162                         break;
 163
 164                 default:
 165                         goto fail;
 166                 }
 167         }
 168         return (char *)ext_acl;
 169
 170       fail:
 171         kfree(ext_acl);
 172         return ERR_PTR(-EINVAL);
 173 }
 174
 175 /*
 176  * Inode operation get_posix_acl().
 177  *
 178  * inode->i_mutex: down
 179  * BKL held [before 2.5.x]
 180  */
 181 struct posix_acl *reiserfs_get_acl(struct inode *inode, int type)
 182 {
 183         char *name, *value;
 184         struct posix_acl *acl, **p_acl;
 185         size_t size;
 186         int retval;
 187         struct reiserfs_inode_info *reiserfs_i = REISERFS_I(inode);
 188
 189         switch (type) {
 190         case ACL_TYPE_ACCESS:
 191                 name = POSIX_ACL_XATTR_ACCESS;
 192                 p_acl = &reiserfs_i->i_acl_access;
 193                 break;
 194         case ACL_TYPE_DEFAULT:
 195                 name = POSIX_ACL_XATTR_DEFAULT;
 196                 p_acl = &reiserfs_i->i_acl_default;
 197                 break;
 198         default:
 199                 return ERR_PTR(-EINVAL);
 200         }
 201
 202         if (IS_ERR(*p_acl)) {
 203                 if (PTR_ERR(*p_acl) == -ENODATA)
 204                         return NULL;
 205         } else if (*p_acl != NULL)
 206                 return posix_acl_dup(*p_acl);
 207
 208         size = reiserfs_xattr_get(inode, name, NULL, 0);
 209         if ((int)size < 0) {
 210                 if (size == -ENODATA || size == -ENOSYS) {
 211                         *p_acl = ERR_PTR(-ENODATA);
 212                         return NULL;
 213                 }
 214                 return ERR_PTR(size);
 215         }
 216
 217         value = kmalloc(size, GFP_NOFS);
 218         if (!value)
 219                 return ERR_PTR(-ENOMEM);
 220
 221         retval = reiserfs_xattr_get(inode, name, value, size);
 222         if (retval == -ENODATA || retval == -ENOSYS) {
 223                 /* This shouldn't actually happen as it should have
 224                    been caught above.. but just in case */
 225                 acl = NULL;
 226                 *p_acl = ERR_PTR(-ENODATA);
 227         } else if (retval < 0) {
 228                 acl = ERR_PTR(retval);
 229         } else {
 230                 acl = posix_acl_from_disk(value, retval);
 231                 *p_acl = posix_acl_dup(acl);
 232         }
 233
 234         kfree(value);
 235         return acl;
 236 }
 237
 238 /*
 239  * Inode operation set_posix_acl().
 240  *
 241  * inode->i_mutex: down
 242  * BKL held [before 2.5.x]
 243  */
 244 static int
 245 reiserfs_set_acl(struct inode *inode, int type, struct posix_acl *acl)
 246 {
 247         char *name;
 248         void *value = NULL;
 249         struct posix_acl **p_acl;
 250         size_t size;
 251         int error;
 252         struct reiserfs_inode_info *reiserfs_i = REISERFS_I(inode);
 253
 254         if (S_ISLNK(inode->i_mode))
 255                 return -EOPNOTSUPP;
 256
 257         switch (type) {
 258         case ACL_TYPE_ACCESS:
 259                 name = POSIX_ACL_XATTR_ACCESS;
 260                 p_acl = &reiserfs_i->i_acl_access;
 261                 if (acl) {
 262                         mode_t mode = inode->i_mode;
 263                         error = posix_acl_equiv_mode(acl, &mode);
 264                         if (error < 0)
 265                                 return error;
 266                         else {
 267                                 inode->i_mode = mode;
 268                                 if (error == 0)
 269                                         acl = NULL;
 270                         }
 271                 }
 272                 break;
 273         case ACL_TYPE_DEFAULT:
 274                 name = POSIX_ACL_XATTR_DEFAULT;
 275                 p_acl = &reiserfs_i->i_acl_default;
 276                 if (!S_ISDIR(inode->i_mode))
 277                         return acl ? -EACCES : 0;
 278                 break;
 279         default:
 280                 return -EINVAL;
 281         }
 282
 283         if (acl) {
 284                 value = posix_acl_to_disk(acl, &size);
 285                 if (IS_ERR(value))
 286                         return (int)PTR_ERR(value);
 287                 error = reiserfs_xattr_set(inode, name, value, size, 0);
 288         } else {
 289                 error = reiserfs_xattr_del(inode, name);
 290                 if (error == -ENODATA) {
 291                         /* This may seem odd here, but it means that the ACL was set
 292                          * with a value representable with mode bits. If there was
 293                          * an ACL before, reiserfs_xattr_del already dirtied the inode.
 294                          */
 295                         mark_inode_dirty(inode);
 296                         error = 0;
 297                 }
 298         }
 299
 300         kfree(value);
 301
 302         if (!error) {
 303                 /* Release the old one */
 304                 if (!IS_ERR(*p_acl) && *p_acl)
 305                         posix_acl_release(*p_acl);
 306
 307                 if (acl == NULL)
 308                         *p_acl = ERR_PTR(-ENODATA);
 309                 else
 310                         *p_acl = posix_acl_dup(acl);
 311         }
 312
 313         return error;
 314 }
 315
 316 /* dir->i_mutex: locked,
 317  * inode is new and not released into the wild yet */
 318 int
 319 reiserfs_inherit_default_acl(struct inode *dir, struct dentry *dentry,
 320                              struct inode *inode)
 321 {
 322         struct posix_acl *acl;
 323         int err = 0;
 324
 325         /* ACLs only get applied to files and directories */
 326         if (S_ISLNK(inode->i_mode))
 327                 return 0;
 328
 329         /* ACLs can only be used on "new" objects, so if it's an old object
 330          * there is nothing to inherit from */
 331         if (get_inode_sd_version(dir) == STAT_DATA_V1)
 332                 goto apply_umask;
 333
 334         /* Don't apply ACLs to objects in the .reiserfs_priv tree.. This
 335          * would be useless since permissions are ignored, and a pain because
 336          * it introduces locking cycles */
 337         if (is_reiserfs_priv_object(dir)) {
 338                 reiserfs_mark_inode_private(inode);
 339                 goto apply_umask;
 340         }
 341
 342         acl = reiserfs_get_acl(dir, ACL_TYPE_DEFAULT);
 343         if (IS_ERR(acl)) {
 344                 if (PTR_ERR(acl) == -ENODATA)
 345                         goto apply_umask;
 346                 return PTR_ERR(acl);
 347         }
 348
 349         if (acl) {
 350                 struct posix_acl *acl_copy;
 351                 mode_t mode = inode->i_mode;
 352                 int need_acl;
 353
 354                 /* Copy the default ACL to the default ACL of a new directory */
 355                 if (S_ISDIR(inode->i_mode)) {
 356                         err = reiserfs_set_acl(inode, ACL_TYPE_DEFAULT, acl);
 357                         if (err)
 358                                 goto cleanup;
 359                 }
 360
 361                 /* Now we reconcile the new ACL and the mode,
 362                    potentially modifying both */
 363                 acl_copy = posix_acl_clone(acl, GFP_NOFS);
 364                 if (!acl_copy) {
 365                         err = -ENOMEM;
 366                         goto cleanup;
 367                 }
 368
 369                 need_acl = posix_acl_create_masq(acl_copy, &mode);
 370                 if (need_acl >= 0) {
 371                         if (mode != inode->i_mode) {
 372                                 inode->i_mode = mode;
 373                         }
 374
 375                         /* If we need an ACL.. */
 376                         if (need_acl > 0) {
 377                                 err =
 378                                     reiserfs_set_acl(inode, ACL_TYPE_ACCESS,
 379                                                      acl_copy);
 380                                 if (err)
 381                                         goto cleanup_copy;
 382                         }
 383                 }
 384               cleanup_copy:
 385                 posix_acl_release(acl_copy);
 386               cleanup:
 387                 posix_acl_release(acl);
 388         } else {
 389               apply_umask:
 390                 /* no ACL, apply umask */
 391                 inode->i_mode &= ~current->fs->umask;
 392         }
 393
 394         return err;
 395 }
 396
 397 /* Looks up and caches the result of the default ACL.
 398  * We do this so that we don't need to carry the xattr_sem into
 399  * reiserfs_new_inode if we don't need to */
 400 int reiserfs_cache_default_acl(struct inode *inode)
 401 {
 402         int ret = 0;
 403         if (reiserfs_posixacl(inode->i_sb) && !is_reiserfs_priv_object(inode)) {
 404                 struct posix_acl *acl;
 405                 reiserfs_read_lock_xattr_i(inode);
 406                 reiserfs_read_lock_xattrs(inode->i_sb);
 407                 acl = reiserfs_get_acl(inode, ACL_TYPE_DEFAULT);
 408                 reiserfs_read_unlock_xattrs(inode->i_sb);
 409                 reiserfs_read_unlock_xattr_i(inode);
 410                 ret = acl ? 1 : 0;
 411                 posix_acl_release(acl);
 412         }
 413
 414         return ret;
 415 }
 416
 417 int reiserfs_acl_chmod(struct inode *inode)
 418 {
 419         struct posix_acl *acl, *clone;
 420         int error;
 421
 422         if (S_ISLNK(inode->i_mode))
 423                 return -EOPNOTSUPP;
 424
 425         if (get_inode_sd_version(inode) == STAT_DATA_V1 ||
 426             !reiserfs_posixacl(inode->i_sb)) {
 427                 return 0;
 428         }
 429
 430         reiserfs_read_lock_xattrs(inode->i_sb);
 431         acl = reiserfs_get_acl(inode, ACL_TYPE_ACCESS);
 432         reiserfs_read_unlock_xattrs(inode->i_sb);
 433         if (!acl)
 434                 return 0;
 435         if (IS_ERR(acl))
 436                 return PTR_ERR(acl);
 437         clone = posix_acl_clone(acl, GFP_NOFS);
 438         posix_acl_release(acl);
 439         if (!clone)
 440                 return -ENOMEM;
 441         error = posix_acl_chmod_masq(clone, inode->i_mode);
 442         if (!error) {
 443                 int lock = !has_xattr_dir(inode);
 444                 reiserfs_write_lock_xattr_i(inode);
 445                 if (lock)
 446                         reiserfs_write_lock_xattrs(inode->i_sb);
 447                 else
 448                         reiserfs_read_lock_xattrs(inode->i_sb);
 449                 error = reiserfs_set_acl(inode, ACL_TYPE_ACCESS, clone);
 450                 if (lock)
 451                         reiserfs_write_unlock_xattrs(inode->i_sb);
 452                 else
 453                         reiserfs_read_unlock_xattrs(inode->i_sb);
 454                 reiserfs_write_unlock_xattr_i(inode);
 455         }
 456         posix_acl_release(clone);
 457         return error;
 458 }
 459
 460 static int
 461 posix_acl_access_get(struct inode *inode, const char *name,
 462                      void *buffer, size_t size)
 463 {
 464         if (strlen(name) != sizeof(POSIX_ACL_XATTR_ACCESS) - 1)
 465                 return -EINVAL;
 466         return xattr_get_acl(inode, ACL_TYPE_ACCESS, buffer, size);
 467 }
 468
 469 static int
 470 posix_acl_access_set(struct inode *inode, const char *name,
 471                      const void *value, size_t size, int flags)
 472 {
 473         if (strlen(name) != sizeof(POSIX_ACL_XATTR_ACCESS) - 1)
 474                 return -EINVAL;
 475         return xattr_set_acl(inode, ACL_TYPE_ACCESS, value, size);
 476 }
 477
 478 static int posix_acl_access_del(struct inode *inode, const char *name)
 479 {
 480         struct reiserfs_inode_info *reiserfs_i = REISERFS_I(inode);
 481         struct posix_acl **acl = &reiserfs_i->i_acl_access;
 482         if (strlen(name) != sizeof(POSIX_ACL_XATTR_ACCESS) - 1)
 483                 return -EINVAL;
 484         if (!IS_ERR(*acl) && *acl) {
 485                 posix_acl_release(*acl);
 486                 *acl = ERR_PTR(-ENODATA);
 487         }
 488
 489         return 0;
 490 }
 491
 492 static int
 493 posix_acl_access_list(struct inode *inode, const char *name, int namelen,
 494                       char *out)
 495 {
 496         int len = namelen;
 497         if (!reiserfs_posixacl(inode->i_sb))
 498                 return 0;
 499         if (out)
 500                 memcpy(out, name, len);
 501
 502         return len;
 503 }
 504
 505 struct reiserfs_xattr_handler posix_acl_access_handler = {
 506         .prefix = POSIX_ACL_XATTR_ACCESS,
 507         .get = posix_acl_access_get,
 508         .set = posix_acl_access_set,
 509         .del = posix_acl_access_del,
 510         .list = posix_acl_access_list,
 511 };
 512
 513 static int
 514 posix_acl_default_get(struct inode *inode, const char *name,
 515                       void *buffer, size_t size)
 516 {
 517         if (strlen(name) != sizeof(POSIX_ACL_XATTR_DEFAULT) - 1)
 518                 return -EINVAL;
 519         return xattr_get_acl(inode, ACL_TYPE_DEFAULT, buffer, size);
 520 }
 521
 522 static int
 523 posix_acl_default_set(struct inode *inode, const char *name,
 524                       const void *value, size_t size, int flags)
 525 {
 526         if (strlen(name) != sizeof(POSIX_ACL_XATTR_DEFAULT) - 1)
 527                 return -EINVAL;
 528         return xattr_set_acl(inode, ACL_TYPE_DEFAULT, value, size);
 529 }
 530
 531 static int posix_acl_default_del(struct inode *inode, const char *name)
 532 {
 533         struct reiserfs_inode_info *reiserfs_i = REISERFS_I(inode);
 534         struct posix_acl **acl = &reiserfs_i->i_acl_default;
 535         if (strlen(name) != sizeof(POSIX_ACL_XATTR_DEFAULT) - 1)
 536                 return -EINVAL;
 537         if (!IS_ERR(*acl) && *acl) {
 538                 posix_acl_release(*acl);
 539                 *acl = ERR_PTR(-ENODATA);
 540         }
 541
 542         return 0;
 543 }
 544
 545 static int
 546 posix_acl_default_list(struct inode *inode, const char *name, int namelen,
 547                        char *out)
 548 {
 549         int len = namelen;
 550         if (!reiserfs_posixacl(inode->i_sb))
 551                 return 0;
 552         if (out)
 553                 memcpy(out, name, len);
 554
 555         return len;
 556 }
 557
 558 struct reiserfs_xattr_handler posix_acl_default_handler = {
 559         .prefix = POSIX_ACL_XATTR_DEFAULT,
 560         .get = posix_acl_default_get,
 561         .set = posix_acl_default_set,
 562         .del = posix_acl_default_del,
 563         .list = posix_acl_default_list,
 564 };