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 = 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         int 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 (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                 if (!IS_ERR(acl))
 232                         *p_acl = posix_acl_dup(acl);
 233         }
 234
 235         kfree(value);
 236         return acl;
 237 }
 238
 239 /*
 240  * Inode operation set_posix_acl().
 241  *
 242  * inode->i_mutex: down
 243  * BKL held [before 2.5.x]
 244  */
 245 static int
 246 reiserfs_set_acl(struct inode *inode, int type, struct posix_acl *acl)
 247 {
 248         char *name;
 249         void *value = NULL;
 250         struct posix_acl **p_acl;
 251         size_t size;
 252         int error;
 253         struct reiserfs_inode_info *reiserfs_i = REISERFS_I(inode);
 254
 255         if (S_ISLNK(inode->i_mode))
 256                 return -EOPNOTSUPP;
 257
 258         switch (type) {
 259         case ACL_TYPE_ACCESS:
 260                 name = POSIX_ACL_XATTR_ACCESS;
 261                 p_acl = &reiserfs_i->i_acl_access;
 262                 if (acl) {
 263                         mode_t mode = inode->i_mode;
 264                         error = posix_acl_equiv_mode(acl, &mode);
 265                         if (error < 0)
 266                                 return error;
 267                         else {
 268                                 inode->i_mode = mode;
 269                                 if (error == 0)
 270                                         acl = NULL;
 271                         }
 272                 }
 273                 break;
 274         case ACL_TYPE_DEFAULT:
 275                 name = POSIX_ACL_XATTR_DEFAULT;
 276                 p_acl = &reiserfs_i->i_acl_default;
 277                 if (!S_ISDIR(inode->i_mode))
 278                         return acl ? -EACCES : 0;
 279                 break;
 280         default:
 281                 return -EINVAL;
 282         }
 283
 284         if (acl) {
 285                 value = posix_acl_to_disk(acl, &size);
 286                 if (IS_ERR(value))
 287                         return (int)PTR_ERR(value);
 288                 error = reiserfs_xattr_set(inode, name, value, size, 0);
 289         } else {
 290                 error = reiserfs_xattr_del(inode, name);
 291                 if (error == -ENODATA) {
 292                         /* This may seem odd here, but it means that the ACL was set
 293                          * with a value representable with mode bits. If there was
 294                          * an ACL before, reiserfs_xattr_del already dirtied the inode.
 295                          */
 296                         mark_inode_dirty(inode);
 297                         error = 0;
 298                 }
 299         }
 300
 301         kfree(value);
 302
 303         if (!error) {
 304                 /* Release the old one */
 305                 if (!IS_ERR(*p_acl) && *p_acl)
 306                         posix_acl_release(*p_acl);
 307
 308                 if (acl == NULL)
 309                         *p_acl = ERR_PTR(-ENODATA);
 310                 else
 311                         *p_acl = posix_acl_dup(acl);
 312         }
 313
 314         return error;
 315 }
 316
 317 /* dir->i_mutex: locked,
 318  * inode is new and not released into the wild yet */
 319 int
 320 reiserfs_inherit_default_acl(struct inode *dir, struct dentry *dentry,
 321                              struct inode *inode)
 322 {
 323         struct posix_acl *acl;
 324         int err = 0;
 325
 326         /* ACLs only get applied to files and directories */
 327         if (S_ISLNK(inode->i_mode))
 328                 return 0;
 329
 330         /* ACLs can only be used on "new" objects, so if it's an old object
 331          * there is nothing to inherit from */
 332         if (get_inode_sd_version(dir) == STAT_DATA_V1)
 333                 goto apply_umask;
 334
 335         /* Don't apply ACLs to objects in the .reiserfs_priv tree.. This
 336          * would be useless since permissions are ignored, and a pain because
 337          * it introduces locking cycles */
 338         if (is_reiserfs_priv_object(dir)) {
 339                 reiserfs_mark_inode_private(inode);
 340                 goto apply_umask;
 341         }
 342
 343         acl = reiserfs_get_acl(dir, ACL_TYPE_DEFAULT);
 344         if (IS_ERR(acl)) {
 345                 if (PTR_ERR(acl) == -ENODATA)
 346                         goto apply_umask;
 347                 return PTR_ERR(acl);
 348         }
 349
 350         if (acl) {
 351                 struct posix_acl *acl_copy;
 352                 mode_t mode = inode->i_mode;
 353                 int need_acl;
 354
 355                 /* Copy the default ACL to the default ACL of a new directory */
 356                 if (S_ISDIR(inode->i_mode)) {
 357                         err = reiserfs_set_acl(inode, ACL_TYPE_DEFAULT, acl);
 358                         if (err)
 359                                 goto cleanup;
 360                 }
 361
 362                 /* Now we reconcile the new ACL and the mode,
 363                    potentially modifying both */
 364                 acl_copy = posix_acl_clone(acl, GFP_NOFS);
 365                 if (!acl_copy) {
 366                         err = -ENOMEM;
 367                         goto cleanup;
 368                 }
 369
 370                 need_acl = posix_acl_create_masq(acl_copy, &mode);
 371                 if (need_acl >= 0) {
 372                         if (mode != inode->i_mode) {
 373                                 inode->i_mode = mode;
 374                         }
 375
 376                         /* If we need an ACL.. */
 377                         if (need_acl > 0) {
 378                                 err =
 379                                     reiserfs_set_acl(inode, ACL_TYPE_ACCESS,
 380                                                      acl_copy);
 381                                 if (err)
 382                                         goto cleanup_copy;
 383                         }
 384                 }
 385               cleanup_copy:
 386                 posix_acl_release(acl_copy);
 387               cleanup:
 388                 posix_acl_release(acl);
 389         } else {
 390               apply_umask:
 391                 /* no ACL, apply umask */
 392                 inode->i_mode &= ~current->fs->umask;
 393         }
 394
 395         return err;
 396 }
 397
 398 /* Looks up and caches the result of the default ACL.
 399  * We do this so that we don't need to carry the xattr_sem into
 400  * reiserfs_new_inode if we don't need to */
 401 int reiserfs_cache_default_acl(struct inode *inode)
 402 {
 403         int ret = 0;
 404         if (reiserfs_posixacl(inode->i_sb) && !is_reiserfs_priv_object(inode)) {
 405                 struct posix_acl *acl;
 406                 reiserfs_read_lock_xattr_i(inode);
 407                 reiserfs_read_lock_xattrs(inode->i_sb);
 408                 acl = reiserfs_get_acl(inode, ACL_TYPE_DEFAULT);
 409                 reiserfs_read_unlock_xattrs(inode->i_sb);
 410                 reiserfs_read_unlock_xattr_i(inode);
 411                 ret = (acl && !IS_ERR(acl));
 412                 if (ret)
 413                         posix_acl_release(acl);
 414         }
 415
 416         return ret;
 417 }
 418
 419 int reiserfs_acl_chmod(struct inode *inode)
 420 {
 421         struct posix_acl *acl, *clone;
 422         int error;
 423
 424         if (S_ISLNK(inode->i_mode))
 425                 return -EOPNOTSUPP;
 426
 427         if (get_inode_sd_version(inode) == STAT_DATA_V1 ||
 428             !reiserfs_posixacl(inode->i_sb)) {
 429                 return 0;
 430         }
 431
 432         reiserfs_read_lock_xattrs(inode->i_sb);
 433         acl = reiserfs_get_acl(inode, ACL_TYPE_ACCESS);
 434         reiserfs_read_unlock_xattrs(inode->i_sb);
 435         if (!acl)
 436                 return 0;
 437         if (IS_ERR(acl))
 438                 return PTR_ERR(acl);
 439         clone = posix_acl_clone(acl, GFP_NOFS);
 440         posix_acl_release(acl);
 441         if (!clone)
 442                 return -ENOMEM;
 443         error = posix_acl_chmod_masq(clone, inode->i_mode);
 444         if (!error) {
 445                 int lock = !has_xattr_dir(inode);
 446                 reiserfs_write_lock_xattr_i(inode);
 447                 if (lock)
 448                         reiserfs_write_lock_xattrs(inode->i_sb);
 449                 else
 450                         reiserfs_read_lock_xattrs(inode->i_sb);
 451                 error = reiserfs_set_acl(inode, ACL_TYPE_ACCESS, clone);
 452                 if (lock)
 453                         reiserfs_write_unlock_xattrs(inode->i_sb);
 454                 else
 455                         reiserfs_read_unlock_xattrs(inode->i_sb);
 456                 reiserfs_write_unlock_xattr_i(inode);
 457         }
 458         posix_acl_release(clone);
 459         return error;
 460 }
 461
 462 static int
 463 posix_acl_access_get(struct inode *inode, const char *name,
 464                      void *buffer, size_t size)
 465 {
 466         if (strlen(name) != sizeof(POSIX_ACL_XATTR_ACCESS) - 1)
 467                 return -EINVAL;
 468         return xattr_get_acl(inode, ACL_TYPE_ACCESS, buffer, size);
 469 }
 470
 471 static int
 472 posix_acl_access_set(struct inode *inode, const char *name,
 473                      const void *value, size_t size, int flags)
 474 {
 475         if (strlen(name) != sizeof(POSIX_ACL_XATTR_ACCESS) - 1)
 476                 return -EINVAL;
 477         return xattr_set_acl(inode, ACL_TYPE_ACCESS, value, size);
 478 }
 479
 480 static int posix_acl_access_del(struct inode *inode, const char *name)
 481 {
 482         struct reiserfs_inode_info *reiserfs_i = REISERFS_I(inode);
 483         struct posix_acl **acl = &reiserfs_i->i_acl_access;
 484         if (strlen(name) != sizeof(POSIX_ACL_XATTR_ACCESS) - 1)
 485                 return -EINVAL;
 486         if (!IS_ERR(*acl) && *acl) {
 487                 posix_acl_release(*acl);
 488                 *acl = ERR_PTR(-ENODATA);
 489         }
 490
 491         return 0;
 492 }
 493
 494 static int
 495 posix_acl_access_list(struct inode *inode, const char *name, int namelen,
 496                       char *out)
 497 {
 498         int len = namelen;
 499         if (!reiserfs_posixacl(inode->i_sb))
 500                 return 0;
 501         if (out)
 502                 memcpy(out, name, len);
 503
 504         return len;
 505 }
 506
 507 struct reiserfs_xattr_handler posix_acl_access_handler = {
 508         .prefix = POSIX_ACL_XATTR_ACCESS,
 509         .get = posix_acl_access_get,
 510         .set = posix_acl_access_set,
 511         .del = posix_acl_access_del,
 512         .list = posix_acl_access_list,
 513 };
 514
 515 static int
 516 posix_acl_default_get(struct inode *inode, const char *name,
 517                       void *buffer, size_t size)
 518 {
 519         if (strlen(name) != sizeof(POSIX_ACL_XATTR_DEFAULT) - 1)
 520                 return -EINVAL;
 521         return xattr_get_acl(inode, ACL_TYPE_DEFAULT, buffer, size);
 522 }
 523
 524 static int
 525 posix_acl_default_set(struct inode *inode, const char *name,
 526                       const void *value, size_t size, int flags)
 527 {
 528         if (strlen(name) != sizeof(POSIX_ACL_XATTR_DEFAULT) - 1)
 529                 return -EINVAL;
 530         return xattr_set_acl(inode, ACL_TYPE_DEFAULT, value, size);
 531 }
 532
 533 static int posix_acl_default_del(struct inode *inode, const char *name)
 534 {
 535         struct reiserfs_inode_info *reiserfs_i = REISERFS_I(inode);
 536         struct posix_acl **acl = &reiserfs_i->i_acl_default;
 537         if (strlen(name) != sizeof(POSIX_ACL_XATTR_DEFAULT) - 1)
 538                 return -EINVAL;
 539         if (!IS_ERR(*acl) && *acl) {
 540                 posix_acl_release(*acl);
 541                 *acl = ERR_PTR(-ENODATA);
 542         }
 543
 544         return 0;
 545 }
 546
 547 static int
 548 posix_acl_default_list(struct inode *inode, const char *name, int namelen,
 549                        char *out)
 550 {
 551         int len = namelen;
 552         if (!reiserfs_posixacl(inode->i_sb))
 553                 return 0;
 554         if (out)
 555                 memcpy(out, name, len);
 556
 557         return len;
 558 }
 559
 560 struct reiserfs_xattr_handler posix_acl_default_handler = {
 561         .prefix = POSIX_ACL_XATTR_DEFAULT,
 562         .get = posix_acl_default_get,
 563         .set = posix_acl_default_set,
 564         .del = posix_acl_default_del,
 565         .list = posix_acl_default_list,
 566 };