fs/reiserfs/xattr_acl.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/capability.h>
   3 #include <linux/fs.h>
   4 #include <linux/posix_acl.h>
   5 #include "reiserfs.h"
   6 #include <linux/errno.h>
   7 #include <linux/pagemap.h>
   8 #include <linux/xattr.h>
   9 #include <linux/slab.h>
  10 #include <linux/posix_acl_xattr.h>
  11 #include "xattr.h"
  12 #include "acl.h"
  13 #include <linux/uaccess.h>
  14
  15 static int __reiserfs_set_acl(struct reiserfs_transaction_handle *th,
  16                             struct inode *inode, int type,
  17                             struct posix_acl *acl);
  18
  19
  20 int
  21 reiserfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
  22 {
  23         int error, error2;
  24         struct reiserfs_transaction_handle th;
  25         size_t jcreate_blocks;
  26         int size = acl ? posix_acl_xattr_size(acl->a_count) : 0;
  27         int update_mode = 0;
  28         umode_t mode = inode->i_mode;
  29
  30         /*
  31          * Pessimism: We can't assume that anything from the xattr root up
  32          * has been created.
  33          */
  34
  35         jcreate_blocks = reiserfs_xattr_jcreate_nblocks(inode) +
  36                          reiserfs_xattr_nblocks(inode, size) * 2;
  37
  38         reiserfs_write_lock(inode->i_sb);
  39         error = journal_begin(&th, inode->i_sb, jcreate_blocks);
  40         reiserfs_write_unlock(inode->i_sb);
  41         if (error == 0) {
  42                 if (type == ACL_TYPE_ACCESS && acl) {
  43                         error = posix_acl_update_mode(inode, &mode, &acl);
  44                         if (error)
  45                                 goto unlock;
  46                         update_mode = 1;
  47                 }
  48                 error = __reiserfs_set_acl(&th, inode, type, acl);
  49                 if (!error && update_mode)
  50                         inode->i_mode = mode;
  51 unlock:
  52                 reiserfs_write_lock(inode->i_sb);
  53                 error2 = journal_end(&th);
  54                 reiserfs_write_unlock(inode->i_sb);
  55                 if (error2)
  56                         error = error2;
  57         }
  58
  59         return error;
  60 }
  61
  62 /*
  63  * Convert from filesystem to in-memory representation.
  64  */
  65 static struct posix_acl *reiserfs_posix_acl_from_disk(const void *value, size_t size)
  66 {
  67         const char *end = (char *)value + size;
  68         int n, count;
  69         struct posix_acl *acl;
  70
  71         if (!value)
  72                 return NULL;
  73         if (size < sizeof(reiserfs_acl_header))
  74                 return ERR_PTR(-EINVAL);
  75         if (((reiserfs_acl_header *) value)->a_version !=
  76             cpu_to_le32(REISERFS_ACL_VERSION))
  77                 return ERR_PTR(-EINVAL);
  78         value = (char *)value + sizeof(reiserfs_acl_header);
  79         count = reiserfs_acl_count(size);
  80         if (count < 0)
  81                 return ERR_PTR(-EINVAL);
  82         if (count == 0)
  83                 return NULL;
  84         acl = posix_acl_alloc(count, GFP_NOFS);
  85         if (!acl)
  86                 return ERR_PTR(-ENOMEM);
  87         for (n = 0; n < count; n++) {
  88                 reiserfs_acl_entry *entry = (reiserfs_acl_entry *) value;
  89                 if ((char *)value + sizeof(reiserfs_acl_entry_short) > end)
  90                         goto fail;
  91                 acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag);
  92                 acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
  93                 switch (acl->a_entries[n].e_tag) {
  94                 case ACL_USER_OBJ:
  95                 case ACL_GROUP_OBJ:
  96                 case ACL_MASK:
  97                 case ACL_OTHER:
  98                         value = (char *)value +
  99                             sizeof(reiserfs_acl_entry_short);
 100                         break;
 101
 102                 case ACL_USER:
 103                         value = (char *)value + sizeof(reiserfs_acl_entry);
 104                         if ((char *)value > end)
 105                                 goto fail;
 106                         acl->a_entries[n].e_uid =
 107                                 make_kuid(&init_user_ns,
 108                                           le32_to_cpu(entry->e_id));
 109                         break;
 110                 case ACL_GROUP:
 111                         value = (char *)value + sizeof(reiserfs_acl_entry);
 112                         if ((char *)value > end)
 113                                 goto fail;
 114                         acl->a_entries[n].e_gid =
 115                                 make_kgid(&init_user_ns,
 116                                           le32_to_cpu(entry->e_id));
 117                         break;
 118
 119                 default:
 120                         goto fail;
 121                 }
 122         }
 123         if (value != end)
 124                 goto fail;
 125         return acl;
 126
 127 fail:
 128         posix_acl_release(acl);
 129         return ERR_PTR(-EINVAL);
 130 }
 131
 132 /*
 133  * Convert from in-memory to filesystem representation.
 134  */
 135 static void *reiserfs_posix_acl_to_disk(const struct posix_acl *acl, size_t * size)
 136 {
 137         reiserfs_acl_header *ext_acl;
 138         char *e;
 139         int n;
 140
 141         *size = reiserfs_acl_size(acl->a_count);
 142         ext_acl = kmalloc(sizeof(reiserfs_acl_header) +
 143                                                   acl->a_count *
 144                                                   sizeof(reiserfs_acl_entry),
 145                                                   GFP_NOFS);
 146         if (!ext_acl)
 147                 return ERR_PTR(-ENOMEM);
 148         ext_acl->a_version = cpu_to_le32(REISERFS_ACL_VERSION);
 149         e = (char *)ext_acl + sizeof(reiserfs_acl_header);
 150         for (n = 0; n < acl->a_count; n++) {
 151                 const struct posix_acl_entry *acl_e = &acl->a_entries[n];
 152                 reiserfs_acl_entry *entry = (reiserfs_acl_entry *) e;
 153                 entry->e_tag = cpu_to_le16(acl->a_entries[n].e_tag);
 154                 entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
 155                 switch (acl->a_entries[n].e_tag) {
 156                 case ACL_USER:
 157                         entry->e_id = cpu_to_le32(
 158                                 from_kuid(&init_user_ns, acl_e->e_uid));
 159                         e += sizeof(reiserfs_acl_entry);
 160                         break;
 161                 case ACL_GROUP:
 162                         entry->e_id = cpu_to_le32(
 163                                 from_kgid(&init_user_ns, acl_e->e_gid));
 164                         e += sizeof(reiserfs_acl_entry);
 165                         break;
 166
 167                 case ACL_USER_OBJ:
 168                 case ACL_GROUP_OBJ:
 169                 case ACL_MASK:
 170                 case ACL_OTHER:
 171                         e += sizeof(reiserfs_acl_entry_short);
 172                         break;
 173
 174                 default:
 175                         goto fail;
 176                 }
 177         }
 178         return (char *)ext_acl;
 179
 180 fail:
 181         kfree(ext_acl);
 182         return ERR_PTR(-EINVAL);
 183 }
 184
 185 /*
 186  * Inode operation get_posix_acl().
 187  *
 188  * inode->i_mutex: down
 189  * BKL held [before 2.5.x]
 190  */
 191 struct posix_acl *reiserfs_get_acl(struct inode *inode, int type)
 192 {
 193         char *name, *value;
 194         struct posix_acl *acl;
 195         int size;
 196         int retval;
 197
 198         switch (type) {
 199         case ACL_TYPE_ACCESS:
 200                 name = XATTR_NAME_POSIX_ACL_ACCESS;
 201                 break;
 202         case ACL_TYPE_DEFAULT:
 203                 name = XATTR_NAME_POSIX_ACL_DEFAULT;
 204                 break;
 205         default:
 206                 BUG();
 207         }
 208
 209         size = reiserfs_xattr_get(inode, name, NULL, 0);
 210         if (size < 0) {
 211                 if (size == -ENODATA || size == -ENOSYS)
 212                         return NULL;
 213                 return ERR_PTR(size);
 214         }
 215
 216         value = kmalloc(size, GFP_NOFS);
 217         if (!value)
 218                 return ERR_PTR(-ENOMEM);
 219
 220         retval = reiserfs_xattr_get(inode, name, value, size);
 221         if (retval == -ENODATA || retval == -ENOSYS) {
 222                 /*
 223                  * This shouldn't actually happen as it should have
 224                  * been caught above.. but just in case
 225                  */
 226                 acl = NULL;
 227         } else if (retval < 0) {
 228                 acl = ERR_PTR(retval);
 229         } else {
 230                 acl = reiserfs_posix_acl_from_disk(value, retval);
 231         }
 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 = XATTR_NAME_POSIX_ACL_ACCESS;
 255                 break;
 256         case ACL_TYPE_DEFAULT:
 257                 name = XATTR_NAME_POSIX_ACL_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(inode);
 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 = 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 }