LXR linux/fs/reiserfs/xattr

   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
  15static int __reiserfs_set_acl(struct reiserfs_transaction_handle *th,
  16                            struct inode *inode, int type,
  17                            struct posix_acl *acl);
  18
  19
  20int
  21reiserfs_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;
  51unlock:
  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 */
  65static 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
 127fail:
 128        posix_acl_release(acl);
 129        return ERR_PTR(-EINVAL);
 130}
 131
 132/*
 133 * Convert from in-memory to filesystem representation.
 134 */
 135static 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
 180fail:
 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 */
 191struct 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 */
 243static 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 */
 299int
 300reiserfs_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
 346apply_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 */
 363int 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 */
 396int 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}
 406