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                 error = __reiserfs_set_acl(&th, inode, type, acl);
  41                 reiserfs_write_lock(inode->i_sb);
  42                 error2 = journal_end(&th);
  43                 reiserfs_write_unlock(inode->i_sb);
  44                 if (error2)
  45                         error = error2;
  46         }
  47
  48         return error;
  49 }
  50
  51 /*
  52  * Convert from filesystem to in-memory representation.
  53  */
  54 static struct posix_acl *reiserfs_posix_acl_from_disk(const void *value, size_t size)
  55 {
  56         const char *end = (char *)value + size;
  57         int n, count;
  58         struct posix_acl *acl;
  59
  60         if (!value)
  61                 return NULL;
  62         if (size < sizeof(reiserfs_acl_header))
  63                 return ERR_PTR(-EINVAL);
  64         if (((reiserfs_acl_header *) value)->a_version !=
  65             cpu_to_le32(REISERFS_ACL_VERSION))
  66                 return ERR_PTR(-EINVAL);
  67         value = (char *)value + sizeof(reiserfs_acl_header);
  68         count = reiserfs_acl_count(size);
  69         if (count < 0)
  70                 return ERR_PTR(-EINVAL);
  71         if (count == 0)
  72                 return NULL;
  73         acl = posix_acl_alloc(count, GFP_NOFS);
  74         if (!acl)
  75                 return ERR_PTR(-ENOMEM);
  76         for (n = 0; n < count; n++) {
  77                 reiserfs_acl_entry *entry = (reiserfs_acl_entry *) value;
  78                 if ((char *)value + sizeof(reiserfs_acl_entry_short) > end)
  79                         goto fail;
  80                 acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag);
  81                 acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
  82                 switch (acl->a_entries[n].e_tag) {
  83                 case ACL_USER_OBJ:
  84                 case ACL_GROUP_OBJ:
  85                 case ACL_MASK:
  86                 case ACL_OTHER:
  87                         value = (char *)value +
  88                             sizeof(reiserfs_acl_entry_short);
  89                         break;
  90
  91                 case ACL_USER:
  92                         value = (char *)value + sizeof(reiserfs_acl_entry);
  93                         if ((char *)value > end)
  94                                 goto fail;
  95                         acl->a_entries[n].e_uid =
  96                                 make_kuid(&init_user_ns,
  97                                           le32_to_cpu(entry->e_id));
  98                         break;
  99                 case ACL_GROUP:
 100                         value = (char *)value + sizeof(reiserfs_acl_entry);
 101                         if ((char *)value > end)
 102                                 goto fail;
 103                         acl->a_entries[n].e_gid =
 104                                 make_kgid(&init_user_ns,
 105                                           le32_to_cpu(entry->e_id));
 106                         break;
 107
 108                 default:
 109                         goto fail;
 110                 }
 111         }
 112         if (value != end)
 113                 goto fail;
 114         return acl;
 115
 116 fail:
 117         posix_acl_release(acl);
 118         return ERR_PTR(-EINVAL);
 119 }
 120
 121 /*
 122  * Convert from in-memory to filesystem representation.
 123  */
 124 static void *reiserfs_posix_acl_to_disk(const struct posix_acl *acl, size_t * size)
 125 {
 126         reiserfs_acl_header *ext_acl;
 127         char *e;
 128         int n;
 129
 130         *size = reiserfs_acl_size(acl->a_count);
 131         ext_acl = kmalloc(sizeof(reiserfs_acl_header) +
 132                                                   acl->a_count *
 133                                                   sizeof(reiserfs_acl_entry),
 134                                                   GFP_NOFS);
 135         if (!ext_acl)
 136                 return ERR_PTR(-ENOMEM);
 137         ext_acl->a_version = cpu_to_le32(REISERFS_ACL_VERSION);
 138         e = (char *)ext_acl + sizeof(reiserfs_acl_header);
 139         for (n = 0; n < acl->a_count; n++) {
 140                 const struct posix_acl_entry *acl_e = &acl->a_entries[n];
 141                 reiserfs_acl_entry *entry = (reiserfs_acl_entry *) e;
 142                 entry->e_tag = cpu_to_le16(acl->a_entries[n].e_tag);
 143                 entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
 144                 switch (acl->a_entries[n].e_tag) {
 145                 case ACL_USER:
 146                         entry->e_id = cpu_to_le32(
 147                                 from_kuid(&init_user_ns, acl_e->e_uid));
 148                         e += sizeof(reiserfs_acl_entry);
 149                         break;
 150                 case ACL_GROUP:
 151                         entry->e_id = cpu_to_le32(
 152                                 from_kgid(&init_user_ns, acl_e->e_gid));
 153                         e += sizeof(reiserfs_acl_entry);
 154                         break;
 155
 156                 case ACL_USER_OBJ:
 157                 case ACL_GROUP_OBJ:
 158                 case ACL_MASK:
 159                 case ACL_OTHER:
 160                         e += sizeof(reiserfs_acl_entry_short);
 161                         break;
 162
 163                 default:
 164                         goto fail;
 165                 }
 166         }
 167         return (char *)ext_acl;
 168
 169 fail:
 170         kfree(ext_acl);
 171         return ERR_PTR(-EINVAL);
 172 }
 173
 174 /*
 175  * Inode operation get_posix_acl().
 176  *
 177  * inode->i_mutex: down
 178  * BKL held [before 2.5.x]
 179  */
 180 struct posix_acl *reiserfs_get_acl(struct inode *inode, int type)
 181 {
 182         char *name, *value;
 183         struct posix_acl *acl;
 184         int size;
 185         int retval;
 186
 187         switch (type) {
 188         case ACL_TYPE_ACCESS:
 189                 name = XATTR_NAME_POSIX_ACL_ACCESS;
 190                 break;
 191         case ACL_TYPE_DEFAULT:
 192                 name = XATTR_NAME_POSIX_ACL_DEFAULT;
 193                 break;
 194         default:
 195                 BUG();
 196         }
 197
 198         size = reiserfs_xattr_get(inode, name, NULL, 0);
 199         if (size < 0) {
 200                 if (size == -ENODATA || size == -ENOSYS) {
 201                         set_cached_acl(inode, type, NULL);
 202                         return NULL;
 203                 }
 204                 return ERR_PTR(size);
 205         }
 206
 207         value = kmalloc(size, GFP_NOFS);
 208         if (!value)
 209                 return ERR_PTR(-ENOMEM);
 210
 211         retval = reiserfs_xattr_get(inode, name, value, size);
 212         if (retval == -ENODATA || retval == -ENOSYS) {
 213                 /*
 214                  * This shouldn't actually happen as it should have
 215                  * been caught above.. but just in case
 216                  */
 217                 acl = NULL;
 218         } else if (retval < 0) {
 219                 acl = ERR_PTR(retval);
 220         } else {
 221                 acl = reiserfs_posix_acl_from_disk(value, retval);
 222         }
 223         if (!IS_ERR(acl))
 224                 set_cached_acl(inode, type, acl);
 225
 226         kfree(value);
 227         return acl;
 228 }
 229
 230 /*
 231  * Inode operation set_posix_acl().
 232  *
 233  * inode->i_mutex: down
 234  * BKL held [before 2.5.x]
 235  */
 236 static int
 237 __reiserfs_set_acl(struct reiserfs_transaction_handle *th, struct inode *inode,
 238                  int type, struct posix_acl *acl)
 239 {
 240         char *name;
 241         void *value = NULL;
 242         size_t size = 0;
 243         int error;
 244
 245         switch (type) {
 246         case ACL_TYPE_ACCESS:
 247                 name = XATTR_NAME_POSIX_ACL_ACCESS;
 248                 if (acl) {
 249                         error = posix_acl_equiv_mode(acl, &inode->i_mode);
 250                         if (error < 0)
 251                                 return error;
 252                         else {
 253                                 if (error == 0)
 254                                         acl = NULL;
 255                         }
 256                 }
 257                 break;
 258         case ACL_TYPE_DEFAULT:
 259                 name = XATTR_NAME_POSIX_ACL_DEFAULT;
 260                 if (!S_ISDIR(inode->i_mode))
 261                         return acl ? -EACCES : 0;
 262                 break;
 263         default:
 264                 return -EINVAL;
 265         }
 266
 267         if (acl) {
 268                 value = reiserfs_posix_acl_to_disk(acl, &size);
 269                 if (IS_ERR(value))
 270                         return (int)PTR_ERR(value);
 271         }
 272
 273         error = reiserfs_xattr_set_handle(th, inode, name, value, size, 0);
 274
 275         /*
 276          * Ensure that the inode gets dirtied if we're only using
 277          * the mode bits and an old ACL didn't exist. We don't need
 278          * to check if the inode is hashed here since we won't get
 279          * called by reiserfs_inherit_default_acl().
 280          */
 281         if (error == -ENODATA) {
 282                 error = 0;
 283                 if (type == ACL_TYPE_ACCESS) {
 284                         inode->i_ctime = CURRENT_TIME_SEC;
 285                         mark_inode_dirty(inode);
 286                 }
 287         }
 288
 289         kfree(value);
 290
 291         if (!error)
 292                 set_cached_acl(inode, type, acl);
 293
 294         return error;
 295 }
 296
 297 /*
 298  * dir->i_mutex: locked,
 299  * inode is new and not released into the wild yet
 300  */
 301 int
 302 reiserfs_inherit_default_acl(struct reiserfs_transaction_handle *th,
 303                              struct inode *dir, struct dentry *dentry,
 304                              struct inode *inode)
 305 {
 306         struct posix_acl *default_acl, *acl;
 307         int err = 0;
 308
 309         /* ACLs only get applied to files and directories */
 310         if (S_ISLNK(inode->i_mode))
 311                 return 0;
 312
 313         /*
 314          * ACLs can only be used on "new" objects, so if it's an old object
 315          * there is nothing to inherit from
 316          */
 317         if (get_inode_sd_version(dir) == STAT_DATA_V1)
 318                 goto apply_umask;
 319
 320         /*
 321          * Don't apply ACLs to objects in the .reiserfs_priv tree.. This
 322          * would be useless since permissions are ignored, and a pain because
 323          * it introduces locking cycles
 324          */
 325         if (IS_PRIVATE(dir)) {
 326                 inode->i_flags |= S_PRIVATE;
 327                 goto apply_umask;
 328         }
 329
 330         err = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
 331         if (err)
 332                 return err;
 333
 334         if (default_acl) {
 335                 err = __reiserfs_set_acl(th, inode, ACL_TYPE_DEFAULT,
 336                                          default_acl);
 337                 posix_acl_release(default_acl);
 338         }
 339         if (acl) {
 340                 if (!err)
 341                         err = __reiserfs_set_acl(th, inode, ACL_TYPE_ACCESS,
 342                                                  acl);
 343                 posix_acl_release(acl);
 344         }
 345
 346         return err;
 347
 348 apply_umask:
 349         /* no ACL, apply umask */
 350         inode->i_mode &= ~current_umask();
 351         return err;
 352 }
 353
 354 /* This is used to cache the default acl before a new object is created.
 355  * The biggest reason for this is to get an idea of how many blocks will
 356  * actually be required for the create operation if we must inherit an ACL.
 357  * An ACL write can add up to 3 object creations and an additional file write
 358  * so we'd prefer not to reserve that many blocks in the journal if we can.
 359  * It also has the advantage of not loading the ACL with a transaction open,
 360  * this may seem silly, but if the owner of the directory is doing the
 361  * creation, the ACL may not be loaded since the permissions wouldn't require
 362  * it.
 363  * We return the number of blocks required for the transaction.
 364  */
 365 int reiserfs_cache_default_acl(struct inode *inode)
 366 {
 367         struct posix_acl *acl;
 368         int nblocks = 0;
 369
 370         if (IS_PRIVATE(inode))
 371                 return 0;
 372
 373         acl = reiserfs_get_acl(inode, ACL_TYPE_DEFAULT);
 374
 375         if (acl && !IS_ERR(acl)) {
 376                 int size = reiserfs_acl_size(acl->a_count);
 377
 378                 /* Other xattrs can be created during inode creation. We don't
 379                  * want to claim too many blocks, so we check to see if we
 380                  * we need to create the tree to the xattrs, and then we
 381                  * just want two files. */
 382                 nblocks = reiserfs_xattr_jcreate_nblocks(inode);
 383                 nblocks += JOURNAL_BLOCKS_PER_OBJECT(inode->i_sb);
 384
 385                 REISERFS_I(inode)->i_flags |= i_has_xattr_dir;
 386
 387                 /* We need to account for writes + bitmaps for two files */
 388                 nblocks += reiserfs_xattr_nblocks(inode, size) * 4;
 389                 posix_acl_release(acl);
 390         }
 391
 392         return nblocks;
 393 }
 394
 395 /*
 396  * Called under i_mutex
 397  */
 398 int reiserfs_acl_chmod(struct inode *inode)
 399 {
 400         if (IS_PRIVATE(inode))
 401                 return 0;
 402         if (get_inode_sd_version(inode) == STAT_DATA_V1 ||
 403             !reiserfs_posixacl(inode->i_sb))
 404                 return 0;
 405
 406         return posix_acl_chmod(inode, inode->i_mode);
 407 }