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         int update_mode = 0;
  27         umode_t mode = inode->i_mode;
  28
  29         /*
  30          * Pessimism: We can't assume that anything from the xattr root up
  31          * has been created.
  32          */
  33
  34         jcreate_blocks = reiserfs_xattr_jcreate_nblocks(inode) +
  35                          reiserfs_xattr_nblocks(inode, size) * 2;
  36
  37         reiserfs_write_lock(inode->i_sb);
  38         error = journal_begin(&th, inode->i_sb, jcreate_blocks);
  39         reiserfs_write_unlock(inode->i_sb);
  40         if (error == 0) {
  41                 if (type == ACL_TYPE_ACCESS && acl) {
  42                         error = posix_acl_update_mode(inode, &mode, &acl);
  43                         if (error)
  44                                 goto unlock;
  45                         update_mode = 1;
  46                 }
  47                 error = __reiserfs_set_acl(&th, inode, type, acl);
  48                 if (!error && update_mode)
  49                         inode->i_mode = mode;
  50 unlock:
  51                 reiserfs_write_lock(inode->i_sb);
  52                 error2 = journal_end(&th);
  53                 reiserfs_write_unlock(inode->i_sb);
  54                 if (error2)
  55                         error = error2;
  56         }
  57
  58         return error;
  59 }
  60
  61 /*
  62  * Convert from filesystem to in-memory representation.
  63  */
  64 static struct posix_acl *reiserfs_posix_acl_from_disk(const void *value, size_t size)
  65 {
  66         const char *end = (char *)value + size;
  67         int n, count;
  68         struct posix_acl *acl;
  69
  70         if (!value)
  71                 return NULL;
  72         if (size < sizeof(reiserfs_acl_header))
  73                 return ERR_PTR(-EINVAL);
  74         if (((reiserfs_acl_header *) value)->a_version !=
  75             cpu_to_le32(REISERFS_ACL_VERSION))
  76                 return ERR_PTR(-EINVAL);
  77         value = (char *)value + sizeof(reiserfs_acl_header);
  78         count = reiserfs_acl_count(size);
  79         if (count < 0)
  80                 return ERR_PTR(-EINVAL);
  81         if (count == 0)
  82                 return NULL;
  83         acl = posix_acl_alloc(count, GFP_NOFS);
  84         if (!acl)
  85                 return ERR_PTR(-ENOMEM);
  86         for (n = 0; n < count; n++) {
  87                 reiserfs_acl_entry *entry = (reiserfs_acl_entry *) value;
  88                 if ((char *)value + sizeof(reiserfs_acl_entry_short) > end)
  89                         goto fail;
  90                 acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag);
  91                 acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
  92                 switch (acl->a_entries[n].e_tag) {
  93                 case ACL_USER_OBJ:
  94                 case ACL_GROUP_OBJ:
  95                 case ACL_MASK:
  96                 case ACL_OTHER:
  97                         value = (char *)value +
  98                             sizeof(reiserfs_acl_entry_short);
  99                         break;
 100
 101                 case ACL_USER:
 102                         value = (char *)value + sizeof(reiserfs_acl_entry);
 103                         if ((char *)value > end)
 104                                 goto fail;
 105                         acl->a_entries[n].e_uid =
 106                                 make_kuid(&init_user_ns,
 107                                           le32_to_cpu(entry->e_id));
 108                         break;
 109                 case ACL_GROUP:
 110                         value = (char *)value + sizeof(reiserfs_acl_entry);
 111                         if ((char *)value > end)
 112                                 goto fail;
 113                         acl->a_entries[n].e_gid =
 114                                 make_kgid(&init_user_ns,
 115                                           le32_to_cpu(entry->e_id));
 116                         break;
 117
 118                 default:
 119                         goto fail;
 120                 }
 121         }
 122         if (value != end)
 123                 goto fail;
 124         return acl;
 125
 126 fail:
 127         posix_acl_release(acl);
 128         return ERR_PTR(-EINVAL);
 129 }
 130
 131 /*
 132  * Convert from in-memory to filesystem representation.
 133  */
 134 static void *reiserfs_posix_acl_to_disk(const struct posix_acl *acl, size_t * size)
 135 {
 136         reiserfs_acl_header *ext_acl;
 137         char *e;
 138         int n;
 139
 140         *size = reiserfs_acl_size(acl->a_count);
 141         ext_acl = kmalloc(sizeof(reiserfs_acl_header) +
 142                                                   acl->a_count *
 143                                                   sizeof(reiserfs_acl_entry),
 144                                                   GFP_NOFS);
 145         if (!ext_acl)
 146                 return ERR_PTR(-ENOMEM);
 147         ext_acl->a_version = cpu_to_le32(REISERFS_ACL_VERSION);
 148         e = (char *)ext_acl + sizeof(reiserfs_acl_header);
 149         for (n = 0; n < acl->a_count; n++) {
 150                 const struct posix_acl_entry *acl_e = &acl->a_entries[n];
 151                 reiserfs_acl_entry *entry = (reiserfs_acl_entry *) e;
 152                 entry->e_tag = cpu_to_le16(acl->a_entries[n].e_tag);
 153                 entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
 154                 switch (acl->a_entries[n].e_tag) {
 155                 case ACL_USER:
 156                         entry->e_id = cpu_to_le32(
 157                                 from_kuid(&init_user_ns, acl_e->e_uid));
 158                         e += sizeof(reiserfs_acl_entry);
 159                         break;
 160                 case ACL_GROUP:
 161                         entry->e_id = cpu_to_le32(
 162                                 from_kgid(&init_user_ns, acl_e->e_gid));
 163                         e += sizeof(reiserfs_acl_entry);
 164                         break;
 165
 166                 case ACL_USER_OBJ:
 167                 case ACL_GROUP_OBJ:
 168                 case ACL_MASK:
 169                 case ACL_OTHER:
 170                         e += sizeof(reiserfs_acl_entry_short);
 171                         break;
 172
 173                 default:
 174                         goto fail;
 175                 }
 176         }
 177         return (char *)ext_acl;
 178
 179 fail:
 180         kfree(ext_acl);
 181         return ERR_PTR(-EINVAL);
 182 }
 183
 184 /*
 185  * Inode operation get_posix_acl().
 186  *
 187  * inode->i_mutex: down
 188  * BKL held [before 2.5.x]
 189  */
 190 struct posix_acl *reiserfs_get_acl(struct inode *inode, int type)
 191 {
 192         char *name, *value;
 193         struct posix_acl *acl;
 194         int size;
 195         int retval;
 196
 197         switch (type) {
 198         case ACL_TYPE_ACCESS:
 199                 name = XATTR_NAME_POSIX_ACL_ACCESS;
 200                 break;
 201         case ACL_TYPE_DEFAULT:
 202                 name = XATTR_NAME_POSIX_ACL_DEFAULT;
 203                 break;
 204         default:
 205                 BUG();
 206         }
 207
 208         size = reiserfs_xattr_get(inode, name, NULL, 0);
 209         if (size < 0) {
 210                 if (size == -ENODATA || size == -ENOSYS)
 211                         return NULL;
 212                 return ERR_PTR(size);
 213         }
 214
 215         value = kmalloc(size, GFP_NOFS);
 216         if (!value)
 217                 return ERR_PTR(-ENOMEM);
 218
 219         retval = reiserfs_xattr_get(inode, name, value, size);
 220         if (retval == -ENODATA || retval == -ENOSYS) {
 221                 /*
 222                  * This shouldn't actually happen as it should have
 223                  * been caught above.. but just in case
 224                  */
 225                 acl = NULL;
 226         } else if (retval < 0) {
 227                 acl = ERR_PTR(retval);
 228         } else {
 229                 acl = reiserfs_posix_acl_from_disk(value, retval);
 230         }
 231
 232         kfree(value);
 233         return acl;
 234 }
 235
 236 /*
 237  * Inode operation set_posix_acl().
 238  *
 239  * inode->i_mutex: down
 240  * BKL held [before 2.5.x]
 241  */
 242 static int
 243 __reiserfs_set_acl(struct reiserfs_transaction_handle *th, struct inode *inode,
 244                  int type, struct posix_acl *acl)
 245 {
 246         char *name;
 247         void *value = NULL;
 248         size_t size = 0;
 249         int error;
 250
 251         switch (type) {
 252         case ACL_TYPE_ACCESS:
 253                 name = XATTR_NAME_POSIX_ACL_ACCESS;
 254                 break;
 255         case ACL_TYPE_DEFAULT:
 256                 name = XATTR_NAME_POSIX_ACL_DEFAULT;
 257                 if (!S_ISDIR(inode->i_mode))
 258                         return acl ? -EACCES : 0;
 259                 break;
 260         default:
 261                 return -EINVAL;
 262         }
 263
 264         if (acl) {
 265                 value = reiserfs_posix_acl_to_disk(acl, &size);
 266                 if (IS_ERR(value))
 267                         return (int)PTR_ERR(value);
 268         }
 269
 270         error = reiserfs_xattr_set_handle(th, inode, name, value, size, 0);
 271
 272         /*
 273          * Ensure that the inode gets dirtied if we're only using
 274          * the mode bits and an old ACL didn't exist. We don't need
 275          * to check if the inode is hashed here since we won't get
 276          * called by reiserfs_inherit_default_acl().
 277          */
 278         if (error == -ENODATA) {
 279                 error = 0;
 280                 if (type == ACL_TYPE_ACCESS) {
 281                         inode->i_ctime = current_time(inode);
 282                         mark_inode_dirty(inode);
 283                 }
 284         }
 285
 286         kfree(value);
 287
 288         if (!error)
 289                 set_cached_acl(inode, type, acl);
 290
 291         return error;
 292 }
 293
 294 /*
 295  * dir->i_mutex: locked,
 296  * inode is new and not released into the wild yet
 297  */
 298 int
 299 reiserfs_inherit_default_acl(struct reiserfs_transaction_handle *th,
 300                              struct inode *dir, struct dentry *dentry,
 301                              struct inode *inode)
 302 {
 303         struct posix_acl *default_acl, *acl;
 304         int err = 0;
 305
 306         /* ACLs only get applied to files and directories */
 307         if (S_ISLNK(inode->i_mode))
 308                 return 0;
 309
 310         /*
 311          * ACLs can only be used on "new" objects, so if it's an old object
 312          * there is nothing to inherit from
 313          */
 314         if (get_inode_sd_version(dir) == STAT_DATA_V1)
 315                 goto apply_umask;
 316
 317         /*
 318          * Don't apply ACLs to objects in the .reiserfs_priv tree.. This
 319          * would be useless since permissions are ignored, and a pain because
 320          * it introduces locking cycles
 321          */
 322         if (IS_PRIVATE(dir)) {
 323                 inode->i_flags |= S_PRIVATE;
 324                 goto apply_umask;
 325         }
 326
 327         err = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
 328         if (err)
 329                 return err;
 330
 331         if (default_acl) {
 332                 err = __reiserfs_set_acl(th, inode, ACL_TYPE_DEFAULT,
 333                                          default_acl);
 334                 posix_acl_release(default_acl);
 335         }
 336         if (acl) {
 337                 if (!err)
 338                         err = __reiserfs_set_acl(th, inode, ACL_TYPE_ACCESS,
 339                                                  acl);
 340                 posix_acl_release(acl);
 341         }
 342
 343         return err;
 344
 345 apply_umask:
 346         /* no ACL, apply umask */
 347         inode->i_mode &= ~current_umask();
 348         return err;
 349 }
 350
 351 /* This is used to cache the default acl before a new object is created.
 352  * The biggest reason for this is to get an idea of how many blocks will
 353  * actually be required for the create operation if we must inherit an ACL.
 354  * An ACL write can add up to 3 object creations and an additional file write
 355  * so we'd prefer not to reserve that many blocks in the journal if we can.
 356  * It also has the advantage of not loading the ACL with a transaction open,
 357  * this may seem silly, but if the owner of the directory is doing the
 358  * creation, the ACL may not be loaded since the permissions wouldn't require
 359  * it.
 360  * We return the number of blocks required for the transaction.
 361  */
 362 int reiserfs_cache_default_acl(struct inode *inode)
 363 {
 364         struct posix_acl *acl;
 365         int nblocks = 0;
 366
 367         if (IS_PRIVATE(inode))
 368                 return 0;
 369
 370         acl = get_acl(inode, ACL_TYPE_DEFAULT);
 371
 372         if (acl && !IS_ERR(acl)) {
 373                 int size = reiserfs_acl_size(acl->a_count);
 374
 375                 /* Other xattrs can be created during inode creation. We don't
 376                  * want to claim too many blocks, so we check to see if we
 377                  * we need to create the tree to the xattrs, and then we
 378                  * just want two files. */
 379                 nblocks = reiserfs_xattr_jcreate_nblocks(inode);
 380                 nblocks += JOURNAL_BLOCKS_PER_OBJECT(inode->i_sb);
 381
 382                 REISERFS_I(inode)->i_flags |= i_has_xattr_dir;
 383
 384                 /* We need to account for writes + bitmaps for two files */
 385                 nblocks += reiserfs_xattr_nblocks(inode, size) * 4;
 386                 posix_acl_release(acl);
 387         }
 388
 389         return nblocks;
 390 }
 391
 392 /*
 393  * Called under i_mutex
 394  */
 395 int reiserfs_acl_chmod(struct inode *inode)
 396 {
 397         if (IS_PRIVATE(inode))
 398                 return 0;
 399         if (get_inode_sd_version(inode) == STAT_DATA_V1 ||
 400             !reiserfs_posixacl(inode->i_sb))
 401                 return 0;
 402
 403         return posix_acl_chmod(inode, inode->i_mode);
 404 }