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 <linux/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
  19 int
  20 reiserfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
  21 {
  22         int error, error2;
  23         struct reiserfs_transaction_handle th;
  24         size_t jcreate_blocks;
  25         int size = acl ? posix_acl_xattr_size(acl->a_count) : 0;
  26
  27
  28         /*
  29          * Pessimism: We can't assume that anything from the xattr root up
  30          * has been created.
  31          */
  32
  33         jcreate_blocks = reiserfs_xattr_jcreate_nblocks(inode) +
  34                          reiserfs_xattr_nblocks(inode, size) * 2;
  35
  36         reiserfs_write_lock(inode->i_sb);
  37         error = journal_begin(&th, inode->i_sb, jcreate_blocks);
  38         reiserfs_write_unlock(inode->i_sb);
  39         if (error == 0) {
  40                 if (type == ACL_TYPE_ACCESS && acl) {
  41                         error = posix_acl_update_mode(inode, &inode->i_mode,
  42                                                       &acl);
  43                         if (error)
  44                                 goto unlock;
  45                 }
  46                 error = __reiserfs_set_acl(&th, inode, type, acl);
  47 unlock:
  48                 reiserfs_write_lock(inode->i_sb);
  49                 error2 = journal_end(&th);
  50                 reiserfs_write_unlock(inode->i_sb);
  51                 if (error2)
  52                         error = error2;
  53         }
  54
  55         return error;
  56 }
  57
  58 /*
  59  * Convert from filesystem to in-memory representation.
  60  */
  61 static struct posix_acl *reiserfs_posix_acl_from_disk(const void *value, size_t size)
  62 {
  63         const char *end = (char *)value + size;
  64         int n, count;
  65         struct posix_acl *acl;
  66
  67         if (!value)
  68                 return NULL;
  69         if (size < sizeof(reiserfs_acl_header))
  70                 return ERR_PTR(-EINVAL);
  71         if (((reiserfs_acl_header *) value)->a_version !=
  72             cpu_to_le32(REISERFS_ACL_VERSION))
  73                 return ERR_PTR(-EINVAL);
  74         value = (char *)value + sizeof(reiserfs_acl_header);
  75         count = reiserfs_acl_count(size);
  76         if (count < 0)
  77                 return ERR_PTR(-EINVAL);
  78         if (count == 0)
  79                 return NULL;
  80         acl = posix_acl_alloc(count, GFP_NOFS);
  81         if (!acl)
  82                 return ERR_PTR(-ENOMEM);
  83         for (n = 0; n < count; n++) {
  84                 reiserfs_acl_entry *entry = (reiserfs_acl_entry *) value;
  85                 if ((char *)value + sizeof(reiserfs_acl_entry_short) > end)
  86                         goto fail;
  87                 acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag);
  88                 acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
  89                 switch (acl->a_entries[n].e_tag) {
  90                 case ACL_USER_OBJ:
  91                 case ACL_GROUP_OBJ:
  92                 case ACL_MASK:
  93                 case ACL_OTHER:
  94                         value = (char *)value +
  95                             sizeof(reiserfs_acl_entry_short);
  96                         break;
  97
  98                 case ACL_USER:
  99                         value = (char *)value + sizeof(reiserfs_acl_entry);
 100                         if ((char *)value > end)
 101                                 goto fail;
 102                         acl->a_entries[n].e_uid =
 103                                 make_kuid(&init_user_ns,
 104                                           le32_to_cpu(entry->e_id));
 105                         break;
 106                 case ACL_GROUP:
 107                         value = (char *)value + sizeof(reiserfs_acl_entry);
 108                         if ((char *)value > end)
 109                                 goto fail;
 110                         acl->a_entries[n].e_gid =
 111                                 make_kgid(&init_user_ns,
 112                                           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 *reiserfs_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                 const struct posix_acl_entry *acl_e = &acl->a_entries[n];
 148                 reiserfs_acl_entry *entry = (reiserfs_acl_entry *) e;
 149                 entry->e_tag = cpu_to_le16(acl->a_entries[n].e_tag);
 150                 entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
 151                 switch (acl->a_entries[n].e_tag) {
 152                 case ACL_USER:
 153                         entry->e_id = cpu_to_le32(
 154                                 from_kuid(&init_user_ns, acl_e->e_uid));
 155                         e += sizeof(reiserfs_acl_entry);
 156                         break;
 157                 case ACL_GROUP:
 158                         entry->e_id = cpu_to_le32(
 159                                 from_kgid(&init_user_ns, acl_e->e_gid));
 160                         e += sizeof(reiserfs_acl_entry);
 161                         break;
 162
 163                 case ACL_USER_OBJ:
 164                 case ACL_GROUP_OBJ:
 165                 case ACL_MASK:
 166                 case ACL_OTHER:
 167                         e += sizeof(reiserfs_acl_entry_short);
 168                         break;
 169
 170                 default:
 171                         goto fail;
 172                 }
 173         }
 174         return (char *)ext_acl;
 175
 176 fail:
 177         kfree(ext_acl);
 178         return ERR_PTR(-EINVAL);
 179 }
 180
 181 /*
 182  * Inode operation get_posix_acl().
 183  *
 184  * inode->i_mutex: down
 185  * BKL held [before 2.5.x]
 186  */
 187 struct posix_acl *reiserfs_get_acl(struct inode *inode, int type)
 188 {
 189         char *name, *value;
 190         struct posix_acl *acl;
 191         int size;
 192         int retval;
 193
 194         switch (type) {
 195         case ACL_TYPE_ACCESS:
 196                 name = POSIX_ACL_XATTR_ACCESS;
 197                 break;
 198         case ACL_TYPE_DEFAULT:
 199                 name = POSIX_ACL_XATTR_DEFAULT;
 200                 break;
 201         default:
 202                 BUG();
 203         }
 204
 205         size = reiserfs_xattr_get(inode, name, NULL, 0);
 206         if (size < 0) {
 207                 if (size == -ENODATA || size == -ENOSYS) {
 208                         set_cached_acl(inode, type, NULL);
 209                         return NULL;
 210                 }
 211                 return ERR_PTR(size);
 212         }
 213
 214         value = kmalloc(size, GFP_NOFS);
 215         if (!value)
 216                 return ERR_PTR(-ENOMEM);
 217
 218         retval = reiserfs_xattr_get(inode, name, value, size);
 219         if (retval == -ENODATA || retval == -ENOSYS) {
 220                 /*
 221                  * This shouldn't actually happen as it should have
 222                  * been caught above.. but just in case
 223                  */
 224                 acl = NULL;
 225         } else if (retval < 0) {
 226                 acl = ERR_PTR(retval);
 227         } else {
 228                 acl = reiserfs_posix_acl_from_disk(value, retval);
 229         }
 230         if (!IS_ERR(acl))
 231                 set_cached_acl(inode, type, acl);
 232
 233         kfree(value);
 234         return acl;
 235 }
 236
 237 /*
 238  * Inode operation set_posix_acl().
 239  *
 240  * inode->i_mutex: down
 241  * BKL held [before 2.5.x]
 242  */
 243 static int
 244 __reiserfs_set_acl(struct reiserfs_transaction_handle *th, struct inode *inode,
 245                  int type, struct posix_acl *acl)
 246 {
 247         char *name;
 248         void *value = NULL;
 249         size_t size = 0;
 250         int error;
 251
 252         switch (type) {
 253         case ACL_TYPE_ACCESS:
 254                 name = POSIX_ACL_XATTR_ACCESS;
 255                 break;
 256         case ACL_TYPE_DEFAULT:
 257                 name = POSIX_ACL_XATTR_DEFAULT;
 258                 if (!S_ISDIR(inode->i_mode))
 259                         return acl ? -EACCES : 0;
 260                 break;
 261         default:
 262                 return -EINVAL;
 263         }
 264
 265         if (acl) {
 266                 value = reiserfs_posix_acl_to_disk(acl, &size);
 267                 if (IS_ERR(value))
 268                         return (int)PTR_ERR(value);
 269         }
 270
 271         error = reiserfs_xattr_set_handle(th, inode, name, value, size, 0);
 272
 273         /*
 274          * Ensure that the inode gets dirtied if we're only using
 275          * the mode bits and an old ACL didn't exist. We don't need
 276          * to check if the inode is hashed here since we won't get
 277          * called by reiserfs_inherit_default_acl().
 278          */
 279         if (error == -ENODATA) {
 280                 error = 0;
 281                 if (type == ACL_TYPE_ACCESS) {
 282                         inode->i_ctime = CURRENT_TIME_SEC;
 283                         mark_inode_dirty(inode);
 284                 }
 285         }
 286
 287         kfree(value);
 288
 289         if (!error)
 290                 set_cached_acl(inode, type, acl);
 291
 292         return error;
 293 }
 294
 295 /*
 296  * dir->i_mutex: locked,
 297  * inode is new and not released into the wild yet
 298  */
 299 int
 300 reiserfs_inherit_default_acl(struct reiserfs_transaction_handle *th,
 301                              struct inode *dir, struct dentry *dentry,
 302                              struct inode *inode)
 303 {
 304         struct posix_acl *default_acl, *acl;
 305         int err = 0;
 306
 307         /* ACLs only get applied to files and directories */
 308         if (S_ISLNK(inode->i_mode))
 309                 return 0;
 310
 311         /*
 312          * ACLs can only be used on "new" objects, so if it's an old object
 313          * there is nothing to inherit from
 314          */
 315         if (get_inode_sd_version(dir) == STAT_DATA_V1)
 316                 goto apply_umask;
 317
 318         /*
 319          * Don't apply ACLs to objects in the .reiserfs_priv tree.. This
 320          * would be useless since permissions are ignored, and a pain because
 321          * it introduces locking cycles
 322          */
 323         if (IS_PRIVATE(dir)) {
 324                 inode->i_flags |= S_PRIVATE;
 325                 goto apply_umask;
 326         }
 327
 328         err = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
 329         if (err)
 330                 return err;
 331
 332         if (default_acl) {
 333                 err = __reiserfs_set_acl(th, inode, ACL_TYPE_DEFAULT,
 334                                          default_acl);
 335                 posix_acl_release(default_acl);
 336         }
 337         if (acl) {
 338                 if (!err)
 339                         err = __reiserfs_set_acl(th, inode, ACL_TYPE_ACCESS,
 340                                                  acl);
 341                 posix_acl_release(acl);
 342         }
 343
 344         return err;
 345
 346 apply_umask:
 347         /* no ACL, apply umask */
 348         inode->i_mode &= ~current_umask();
 349         return err;
 350 }
 351
 352 /* This is used to cache the default acl before a new object is created.
 353  * The biggest reason for this is to get an idea of how many blocks will
 354  * actually be required for the create operation if we must inherit an ACL.
 355  * An ACL write can add up to 3 object creations and an additional file write
 356  * so we'd prefer not to reserve that many blocks in the journal if we can.
 357  * It also has the advantage of not loading the ACL with a transaction open,
 358  * this may seem silly, but if the owner of the directory is doing the
 359  * creation, the ACL may not be loaded since the permissions wouldn't require
 360  * it.
 361  * We return the number of blocks required for the transaction.
 362  */
 363 int reiserfs_cache_default_acl(struct inode *inode)
 364 {
 365         struct posix_acl *acl;
 366         int nblocks = 0;
 367
 368         if (IS_PRIVATE(inode))
 369                 return 0;
 370
 371         acl = reiserfs_get_acl(inode, ACL_TYPE_DEFAULT);
 372
 373         if (acl && !IS_ERR(acl)) {
 374                 int size = reiserfs_acl_size(acl->a_count);
 375
 376                 /* Other xattrs can be created during inode creation. We don't
 377                  * want to claim too many blocks, so we check to see if we
 378                  * we need to create the tree to the xattrs, and then we
 379                  * just want two files. */
 380                 nblocks = reiserfs_xattr_jcreate_nblocks(inode);
 381                 nblocks += JOURNAL_BLOCKS_PER_OBJECT(inode->i_sb);
 382
 383                 REISERFS_I(inode)->i_flags |= i_has_xattr_dir;
 384
 385                 /* We need to account for writes + bitmaps for two files */
 386                 nblocks += reiserfs_xattr_nblocks(inode, size) * 4;
 387                 posix_acl_release(acl);
 388         }
 389
 390         return nblocks;
 391 }
 392
 393 /*
 394  * Called under i_mutex
 395  */
 396 int reiserfs_acl_chmod(struct inode *inode)
 397 {
 398         if (IS_PRIVATE(inode))
 399                 return 0;
 400         if (get_inode_sd_version(inode) == STAT_DATA_V1 ||
 401             !reiserfs_posixacl(inode->i_sb))
 402                 return 0;
 403
 404         return posix_acl_chmod(inode, inode->i_mode);
 405 }