fs/reiserfs/xattr_acl.c

   1 #include <linux/capability.h>
   2 #include <linux/fs.h>
   3 #include <linux/posix_acl.h>
   4 #include "reiserfs.h"
   5 #include <linux/errno.h>
   6 #include <linux/pagemap.h>
   7 #include <linux/xattr.h>
   8 #include <linux/slab.h>
   9 #include <linux/posix_acl_xattr.h>
  10 #include "xattr.h"
  11 #include "acl.h"
  12 #include <asm/uaccess.h>
  13
  14 static int reiserfs_set_acl(struct reiserfs_transaction_handle *th,
  15                             struct inode *inode, int type,
  16                             struct posix_acl *acl);
  17
  18 static int
  19 posix_acl_set(struct dentry *dentry, const char *name, const void *value,
  20                 size_t size, int flags, int type)
  21 {
  22         struct inode *inode = dentry->d_inode;
  23         struct posix_acl *acl;
  24         int error, error2;
  25         struct reiserfs_transaction_handle th;
  26         size_t jcreate_blocks;
  27         if (!reiserfs_posixacl(inode->i_sb))
  28                 return -EOPNOTSUPP;
  29         if (!inode_owner_or_capable(inode))
  30                 return -EPERM;
  31
  32         if (value) {
  33                 acl = posix_acl_from_xattr(&init_user_ns, value, size);
  34                 if (IS_ERR(acl)) {
  35                         return PTR_ERR(acl);
  36                 } else if (acl) {
  37                         error = posix_acl_valid(acl);
  38                         if (error)
  39                                 goto release_and_out;
  40                 }
  41         } else
  42                 acl = NULL;
  43
  44         /* Pessimism: We can't assume that anything from the xattr root up
  45          * has been created. */
  46
  47         jcreate_blocks = reiserfs_xattr_jcreate_nblocks(inode) +
  48                          reiserfs_xattr_nblocks(inode, size) * 2;
  49
  50         reiserfs_write_lock(inode->i_sb);
  51         error = journal_begin(&th, inode->i_sb, jcreate_blocks);
  52         if (error == 0) {
  53                 error = reiserfs_set_acl(&th, inode, type, acl);
  54                 error2 = journal_end(&th, inode->i_sb, jcreate_blocks);
  55                 if (error2)
  56                         error = error2;
  57         }
  58         reiserfs_write_unlock(inode->i_sb);
  59
  60       release_and_out:
  61         posix_acl_release(acl);
  62         return error;
  63 }
  64
  65 static int
  66 posix_acl_get(struct dentry *dentry, const char *name, void *buffer,
  67                 size_t size, int type)
  68 {
  69         struct posix_acl *acl;
  70         int error;
  71
  72         if (!reiserfs_posixacl(dentry->d_sb))
  73                 return -EOPNOTSUPP;
  74
  75         acl = reiserfs_get_acl(dentry->d_inode, type);
  76         if (IS_ERR(acl))
  77                 return PTR_ERR(acl);
  78         if (acl == NULL)
  79                 return -ENODATA;
  80         error = posix_acl_to_xattr(&init_user_ns, acl, buffer, size);
  81         posix_acl_release(acl);
  82
  83         return error;
  84 }
  85
  86 /*
  87  * Convert from filesystem to in-memory representation.
  88  */
  89 static struct posix_acl *posix_acl_from_disk(const void *value, size_t size)
  90 {
  91         const char *end = (char *)value + size;
  92         int n, count;
  93         struct posix_acl *acl;
  94
  95         if (!value)
  96                 return NULL;
  97         if (size < sizeof(reiserfs_acl_header))
  98                 return ERR_PTR(-EINVAL);
  99         if (((reiserfs_acl_header *) value)->a_version !=
 100             cpu_to_le32(REISERFS_ACL_VERSION))
 101                 return ERR_PTR(-EINVAL);
 102         value = (char *)value + sizeof(reiserfs_acl_header);
 103         count = reiserfs_acl_count(size);
 104         if (count < 0)
 105                 return ERR_PTR(-EINVAL);
 106         if (count == 0)
 107                 return NULL;
 108         acl = posix_acl_alloc(count, GFP_NOFS);
 109         if (!acl)
 110                 return ERR_PTR(-ENOMEM);
 111         for (n = 0; n < count; n++) {
 112                 reiserfs_acl_entry *entry = (reiserfs_acl_entry *) value;
 113                 if ((char *)value + sizeof(reiserfs_acl_entry_short) > end)
 114                         goto fail;
 115                 acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag);
 116                 acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
 117                 switch (acl->a_entries[n].e_tag) {
 118                 case ACL_USER_OBJ:
 119                 case ACL_GROUP_OBJ:
 120                 case ACL_MASK:
 121                 case ACL_OTHER:
 122                         value = (char *)value +
 123                             sizeof(reiserfs_acl_entry_short);
 124                         break;
 125
 126                 case ACL_USER:
 127                         value = (char *)value + sizeof(reiserfs_acl_entry);
 128                         if ((char *)value > end)
 129                                 goto fail;
 130                         acl->a_entries[n].e_uid =
 131                                 make_kuid(&init_user_ns,
 132                                           le32_to_cpu(entry->e_id));
 133                         break;
 134                 case ACL_GROUP:
 135                         value = (char *)value + sizeof(reiserfs_acl_entry);
 136                         if ((char *)value > end)
 137                                 goto fail;
 138                         acl->a_entries[n].e_gid =
 139                                 make_kgid(&init_user_ns,
 140                                           le32_to_cpu(entry->e_id));
 141                         break;
 142
 143                 default:
 144                         goto fail;
 145                 }
 146         }
 147         if (value != end)
 148                 goto fail;
 149         return acl;
 150
 151       fail:
 152         posix_acl_release(acl);
 153         return ERR_PTR(-EINVAL);
 154 }
 155
 156 /*
 157  * Convert from in-memory to filesystem representation.
 158  */
 159 static void *posix_acl_to_disk(const struct posix_acl *acl, size_t * size)
 160 {
 161         reiserfs_acl_header *ext_acl;
 162         char *e;
 163         int n;
 164
 165         *size = reiserfs_acl_size(acl->a_count);
 166         ext_acl = kmalloc(sizeof(reiserfs_acl_header) +
 167                                                   acl->a_count *
 168                                                   sizeof(reiserfs_acl_entry),
 169                                                   GFP_NOFS);
 170         if (!ext_acl)
 171                 return ERR_PTR(-ENOMEM);
 172         ext_acl->a_version = cpu_to_le32(REISERFS_ACL_VERSION);
 173         e = (char *)ext_acl + sizeof(reiserfs_acl_header);
 174         for (n = 0; n < acl->a_count; n++) {
 175                 const struct posix_acl_entry *acl_e = &acl->a_entries[n];
 176                 reiserfs_acl_entry *entry = (reiserfs_acl_entry *) e;
 177                 entry->e_tag = cpu_to_le16(acl->a_entries[n].e_tag);
 178                 entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
 179                 switch (acl->a_entries[n].e_tag) {
 180                 case ACL_USER:
 181                         entry->e_id = cpu_to_le32(
 182                                 from_kuid(&init_user_ns, acl_e->e_uid));
 183                         e += sizeof(reiserfs_acl_entry);
 184                         break;
 185                 case ACL_GROUP:
 186                         entry->e_id = cpu_to_le32(
 187                                 from_kgid(&init_user_ns, acl_e->e_gid));
 188                         e += sizeof(reiserfs_acl_entry);
 189                         break;
 190
 191                 case ACL_USER_OBJ:
 192                 case ACL_GROUP_OBJ:
 193                 case ACL_MASK:
 194                 case ACL_OTHER:
 195                         e += sizeof(reiserfs_acl_entry_short);
 196                         break;
 197
 198                 default:
 199                         goto fail;
 200                 }
 201         }
 202         return (char *)ext_acl;
 203
 204       fail:
 205         kfree(ext_acl);
 206         return ERR_PTR(-EINVAL);
 207 }
 208
 209 /*
 210  * Inode operation get_posix_acl().
 211  *
 212  * inode->i_mutex: down
 213  * BKL held [before 2.5.x]
 214  */
 215 struct posix_acl *reiserfs_get_acl(struct inode *inode, int type)
 216 {
 217         char *name, *value;
 218         struct posix_acl *acl;
 219         int size;
 220         int retval;
 221
 222         acl = get_cached_acl(inode, type);
 223         if (acl != ACL_NOT_CACHED)
 224                 return acl;
 225
 226         switch (type) {
 227         case ACL_TYPE_ACCESS:
 228                 name = POSIX_ACL_XATTR_ACCESS;
 229                 break;
 230         case ACL_TYPE_DEFAULT:
 231                 name = POSIX_ACL_XATTR_DEFAULT;
 232                 break;
 233         default:
 234                 BUG();
 235         }
 236
 237         size = reiserfs_xattr_get(inode, name, NULL, 0);
 238         if (size < 0) {
 239                 if (size == -ENODATA || size == -ENOSYS) {
 240                         set_cached_acl(inode, type, NULL);
 241                         return NULL;
 242                 }
 243                 return ERR_PTR(size);
 244         }
 245
 246         value = kmalloc(size, GFP_NOFS);
 247         if (!value)
 248                 return ERR_PTR(-ENOMEM);
 249
 250         retval = reiserfs_xattr_get(inode, name, value, size);
 251         if (retval == -ENODATA || retval == -ENOSYS) {
 252                 /* This shouldn't actually happen as it should have
 253                    been caught above.. but just in case */
 254                 acl = NULL;
 255         } else if (retval < 0) {
 256                 acl = ERR_PTR(retval);
 257         } else {
 258                 acl = posix_acl_from_disk(value, retval);
 259         }
 260         if (!IS_ERR(acl))
 261                 set_cached_acl(inode, type, acl);
 262
 263         kfree(value);
 264         return acl;
 265 }
 266
 267 /*
 268  * Inode operation set_posix_acl().
 269  *
 270  * inode->i_mutex: down
 271  * BKL held [before 2.5.x]
 272  */
 273 static int
 274 reiserfs_set_acl(struct reiserfs_transaction_handle *th, struct inode *inode,
 275                  int type, struct posix_acl *acl)
 276 {
 277         char *name;
 278         void *value = NULL;
 279         size_t size = 0;
 280         int error;
 281
 282         if (S_ISLNK(inode->i_mode))
 283                 return -EOPNOTSUPP;
 284
 285         switch (type) {
 286         case ACL_TYPE_ACCESS:
 287                 name = POSIX_ACL_XATTR_ACCESS;
 288                 if (acl) {
 289                         error = posix_acl_equiv_mode(acl, &inode->i_mode);
 290                         if (error < 0)
 291                                 return error;
 292                         else {
 293                                 if (error == 0)
 294                                         acl = NULL;
 295                         }
 296                 }
 297                 break;
 298         case ACL_TYPE_DEFAULT:
 299                 name = POSIX_ACL_XATTR_DEFAULT;
 300                 if (!S_ISDIR(inode->i_mode))
 301                         return acl ? -EACCES : 0;
 302                 break;
 303         default:
 304                 return -EINVAL;
 305         }
 306
 307         if (acl) {
 308                 value = posix_acl_to_disk(acl, &size);
 309                 if (IS_ERR(value))
 310                         return (int)PTR_ERR(value);
 311         }
 312
 313         error = reiserfs_xattr_set_handle(th, inode, name, value, size, 0);
 314
 315         /*
 316          * Ensure that the inode gets dirtied if we're only using
 317          * the mode bits and an old ACL didn't exist. We don't need
 318          * to check if the inode is hashed here since we won't get
 319          * called by reiserfs_inherit_default_acl().
 320          */
 321         if (error == -ENODATA) {
 322                 error = 0;
 323                 if (type == ACL_TYPE_ACCESS) {
 324                         inode->i_ctime = CURRENT_TIME_SEC;
 325                         mark_inode_dirty(inode);
 326                 }
 327         }
 328
 329         kfree(value);
 330
 331         if (!error)
 332                 set_cached_acl(inode, type, acl);
 333
 334         return error;
 335 }
 336
 337 /* dir->i_mutex: locked,
 338  * inode is new and not released into the wild yet */
 339 int
 340 reiserfs_inherit_default_acl(struct reiserfs_transaction_handle *th,
 341                              struct inode *dir, struct dentry *dentry,
 342                              struct inode *inode)
 343 {
 344         struct posix_acl *acl;
 345         int err = 0;
 346
 347         /* ACLs only get applied to files and directories */
 348         if (S_ISLNK(inode->i_mode))
 349                 return 0;
 350
 351         /* ACLs can only be used on "new" objects, so if it's an old object
 352          * there is nothing to inherit from */
 353         if (get_inode_sd_version(dir) == STAT_DATA_V1)
 354                 goto apply_umask;
 355
 356         /* Don't apply ACLs to objects in the .reiserfs_priv tree.. This
 357          * would be useless since permissions are ignored, and a pain because
 358          * it introduces locking cycles */
 359         if (IS_PRIVATE(dir)) {
 360                 inode->i_flags |= S_PRIVATE;
 361                 goto apply_umask;
 362         }
 363
 364         acl = reiserfs_get_acl(dir, ACL_TYPE_DEFAULT);
 365         if (IS_ERR(acl))
 366                 return PTR_ERR(acl);
 367
 368         if (acl) {
 369                 /* Copy the default ACL to the default ACL of a new directory */
 370                 if (S_ISDIR(inode->i_mode)) {
 371                         err = reiserfs_set_acl(th, inode, ACL_TYPE_DEFAULT,
 372                                                acl);
 373                         if (err)
 374                                 goto cleanup;
 375                 }
 376
 377                 /* Now we reconcile the new ACL and the mode,
 378                    potentially modifying both */
 379                 err = posix_acl_create(&acl, GFP_NOFS, &inode->i_mode);
 380                 if (err < 0)
 381                         return err;
 382
 383                 /* If we need an ACL.. */
 384                 if (err > 0)
 385                         err = reiserfs_set_acl(th, inode, ACL_TYPE_ACCESS, acl);
 386               cleanup:
 387                 posix_acl_release(acl);
 388         } else {
 389               apply_umask:
 390                 /* no ACL, apply umask */
 391                 inode->i_mode &= ~current_umask();
 392         }
 393
 394         return err;
 395 }
 396
 397 /* This is used to cache the default acl before a new object is created.
 398  * The biggest reason for this is to get an idea of how many blocks will
 399  * actually be required for the create operation if we must inherit an ACL.
 400  * An ACL write can add up to 3 object creations and an additional file write
 401  * so we'd prefer not to reserve that many blocks in the journal if we can.
 402  * It also has the advantage of not loading the ACL with a transaction open,
 403  * this may seem silly, but if the owner of the directory is doing the
 404  * creation, the ACL may not be loaded since the permissions wouldn't require
 405  * it.
 406  * We return the number of blocks required for the transaction.
 407  */
 408 int reiserfs_cache_default_acl(struct inode *inode)
 409 {
 410         struct posix_acl *acl;
 411         int nblocks = 0;
 412
 413         if (IS_PRIVATE(inode))
 414                 return 0;
 415
 416         acl = reiserfs_get_acl(inode, ACL_TYPE_DEFAULT);
 417
 418         if (acl && !IS_ERR(acl)) {
 419                 int size = reiserfs_acl_size(acl->a_count);
 420
 421                 /* Other xattrs can be created during inode creation. We don't
 422                  * want to claim too many blocks, so we check to see if we
 423                  * we need to create the tree to the xattrs, and then we
 424                  * just want two files. */
 425                 nblocks = reiserfs_xattr_jcreate_nblocks(inode);
 426                 nblocks += JOURNAL_BLOCKS_PER_OBJECT(inode->i_sb);
 427
 428                 REISERFS_I(inode)->i_flags |= i_has_xattr_dir;
 429
 430                 /* We need to account for writes + bitmaps for two files */
 431                 nblocks += reiserfs_xattr_nblocks(inode, size) * 4;
 432                 posix_acl_release(acl);
 433         }
 434
 435         return nblocks;
 436 }
 437
 438 int reiserfs_acl_chmod(struct inode *inode)
 439 {
 440         struct reiserfs_transaction_handle th;
 441         struct posix_acl *acl;
 442         size_t size;
 443         int depth;
 444         int error;
 445
 446         if (S_ISLNK(inode->i_mode))
 447                 return -EOPNOTSUPP;
 448
 449         if (get_inode_sd_version(inode) == STAT_DATA_V1 ||
 450             !reiserfs_posixacl(inode->i_sb)) {
 451                 return 0;
 452         }
 453
 454         reiserfs_write_unlock(inode->i_sb);
 455         acl = reiserfs_get_acl(inode, ACL_TYPE_ACCESS);
 456         reiserfs_write_lock(inode->i_sb);
 457         if (!acl)
 458                 return 0;
 459         if (IS_ERR(acl))
 460                 return PTR_ERR(acl);
 461         error = posix_acl_chmod(&acl, GFP_NOFS, inode->i_mode);
 462         if (error)
 463                 return error;
 464
 465         size = reiserfs_xattr_nblocks(inode, reiserfs_acl_size(acl->a_count));
 466         depth = reiserfs_write_lock_once(inode->i_sb);
 467         error = journal_begin(&th, inode->i_sb, size * 2);
 468         if (!error) {
 469                 int error2;
 470                 error = reiserfs_set_acl(&th, inode, ACL_TYPE_ACCESS, acl);
 471                 error2 = journal_end(&th, inode->i_sb, size * 2);
 472                 if (error2)
 473                         error = error2;
 474         }
 475         reiserfs_write_unlock_once(inode->i_sb, depth);
 476         posix_acl_release(acl);
 477         return error;
 478 }
 479
 480 static size_t posix_acl_access_list(struct dentry *dentry, char *list,
 481                                     size_t list_size, const char *name,
 482                                     size_t name_len, int type)
 483 {
 484         const size_t size = sizeof(POSIX_ACL_XATTR_ACCESS);
 485         if (!reiserfs_posixacl(dentry->d_sb))
 486                 return 0;
 487         if (list && size <= list_size)
 488                 memcpy(list, POSIX_ACL_XATTR_ACCESS, size);
 489         return size;
 490 }
 491
 492 const struct xattr_handler reiserfs_posix_acl_access_handler = {
 493         .prefix = POSIX_ACL_XATTR_ACCESS,
 494         .flags = ACL_TYPE_ACCESS,
 495         .get = posix_acl_get,
 496         .set = posix_acl_set,
 497         .list = posix_acl_access_list,
 498 };
 499
 500 static size_t posix_acl_default_list(struct dentry *dentry, char *list,
 501                                      size_t list_size, const char *name,
 502                                      size_t name_len, int type)
 503 {
 504         const size_t size = sizeof(POSIX_ACL_XATTR_DEFAULT);
 505         if (!reiserfs_posixacl(dentry->d_sb))
 506                 return 0;
 507         if (list && size <= list_size)
 508                 memcpy(list, POSIX_ACL_XATTR_DEFAULT, size);
 509         return size;
 510 }
 511
 512 const struct xattr_handler reiserfs_posix_acl_default_handler = {
 513         .prefix = POSIX_ACL_XATTR_DEFAULT,
 514         .flags = ACL_TYPE_DEFAULT,
 515         .get = posix_acl_get,
 516         .set = posix_acl_set,
 517         .list = posix_acl_default_list,
 518 };