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 user_namespace *mnt_userns, struct inode *inode,
  22                 struct posix_acl *acl, int type)
  23{
  24        int error, error2;
  25        struct reiserfs_transaction_handle th;
  26        size_t jcreate_blocks;
  27        int size = acl ? posix_acl_xattr_size(acl->a_count) : 0;
  28        int update_mode = 0;
  29        umode_t mode = inode->i_mode;
  30
  31        /*
  32         * Pessimism: We can't assume that anything from the xattr root up
  33         * has been created.
  34         */
  35
  36        jcreate_blocks = reiserfs_xattr_jcreate_nblocks(inode) +
  37                         reiserfs_xattr_nblocks(inode, size) * 2;
  38
  39        reiserfs_write_lock(inode->i_sb);
  40        error = journal_begin(&th, inode->i_sb, jcreate_blocks);
  41        reiserfs_write_unlock(inode->i_sb);
  42        if (error == 0) {
  43                if (type == ACL_TYPE_ACCESS && acl) {
  44                        error = posix_acl_update_mode(&init_user_ns, inode,
  45                                                      &mode, &acl);
  46                        if (error)
  47                                goto unlock;
  48                        update_mode = 1;
  49                }
  50                error = __reiserfs_set_acl(&th, inode, type, acl);
  51                if (!error && update_mode)
  52                        inode->i_mode = mode;
  53unlock:
  54                reiserfs_write_lock(inode->i_sb);
  55                error2 = journal_end(&th);
  56                reiserfs_write_unlock(inode->i_sb);
  57                if (error2)
  58                        error = error2;
  59        }
  60
  61        return error;
  62}
  63
  64/*
  65 * Convert from filesystem to in-memory representation.
  66 */
  67static struct posix_acl *reiserfs_posix_acl_from_disk(const void *value, size_t size)
  68{
  69        const char *end = (char *)value + size;
  70        int n, count;
  71        struct posix_acl *acl;
  72
  73        if (!value)
  74                return NULL;
  75        if (size < sizeof(reiserfs_acl_header))
  76                return ERR_PTR(-EINVAL);
  77        if (((reiserfs_acl_header *) value)->a_version !=
  78            cpu_to_le32(REISERFS_ACL_VERSION))
  79                return ERR_PTR(-EINVAL);
  80        value = (char *)value + sizeof(reiserfs_acl_header);
  81        count = reiserfs_acl_count(size);
  82        if (count < 0)
  83                return ERR_PTR(-EINVAL);
  84        if (count == 0)
  85                return NULL;
  86        acl = posix_acl_alloc(count, GFP_NOFS);
  87        if (!acl)
  88                return ERR_PTR(-ENOMEM);
  89        for (n = 0; n < count; n++) {
  90                reiserfs_acl_entry *entry = (reiserfs_acl_entry *) value;
  91                if ((char *)value + sizeof(reiserfs_acl_entry_short) > end)
  92                        goto fail;
  93                acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag);
  94                acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
  95                switch (acl->a_entries[n].e_tag) {
  96                case ACL_USER_OBJ:
  97                case ACL_GROUP_OBJ:
  98                case ACL_MASK:
  99                case ACL_OTHER:
 100                        value = (char *)value +
 101                            sizeof(reiserfs_acl_entry_short);
 102                        break;
 103
 104                case ACL_USER:
 105                        value = (char *)value + sizeof(reiserfs_acl_entry);
 106                        if ((char *)value > end)
 107                                goto fail;
 108                        acl->a_entries[n].e_uid = 
 109                                make_kuid(&init_user_ns,
 110                                          le32_to_cpu(entry->e_id));
 111                        break;
 112                case ACL_GROUP:
 113                        value = (char *)value + sizeof(reiserfs_acl_entry);
 114                        if ((char *)value > end)
 115                                goto fail;
 116                        acl->a_entries[n].e_gid =
 117                                make_kgid(&init_user_ns,
 118                                          le32_to_cpu(entry->e_id));
 119                        break;
 120
 121                default:
 122                        goto fail;
 123                }
 124        }
 125        if (value != end)
 126                goto fail;
 127        return acl;
 128
 129fail:
 130        posix_acl_release(acl);
 131        return ERR_PTR(-EINVAL);
 132}
 133
 134/*
 135 * Convert from in-memory to filesystem representation.
 136 */
 137static void *reiserfs_posix_acl_to_disk(const struct posix_acl *acl, size_t * size)
 138{
 139        reiserfs_acl_header *ext_acl;
 140        char *e;
 141        int n;
 142
 143        *size = reiserfs_acl_size(acl->a_count);
 144        ext_acl = kmalloc(sizeof(reiserfs_acl_header) +
 145                                                  acl->a_count *
 146                                                  sizeof(reiserfs_acl_entry),
 147                                                  GFP_NOFS);
 148        if (!ext_acl)
 149                return ERR_PTR(-ENOMEM);
 150        ext_acl->a_version = cpu_to_le32(REISERFS_ACL_VERSION);
 151        e = (char *)ext_acl + sizeof(reiserfs_acl_header);
 152        for (n = 0; n < acl->a_count; n++) {
 153                const struct posix_acl_entry *acl_e = &acl->a_entries[n];
 154                reiserfs_acl_entry *entry = (reiserfs_acl_entry *) e;
 155                entry->e_tag = cpu_to_le16(acl->a_entries[n].e_tag);
 156                entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
 157                switch (acl->a_entries[n].e_tag) {
 158                case ACL_USER:
 159                        entry->e_id = cpu_to_le32(
 160                                from_kuid(&init_user_ns, acl_e->e_uid));
 161                        e += sizeof(reiserfs_acl_entry);
 162                        break;
 163                case ACL_GROUP:
 164                        entry->e_id = cpu_to_le32(
 165                                from_kgid(&init_user_ns, acl_e->e_gid));
 166                        e += sizeof(reiserfs_acl_entry);
 167                        break;
 168
 169                case ACL_USER_OBJ:
 170                case ACL_GROUP_OBJ:
 171                case ACL_MASK:
 172                case ACL_OTHER:
 173                        e += sizeof(reiserfs_acl_entry_short);
 174                        break;
 175
 176                default:
 177                        goto fail;
 178                }
 179        }
 180        return (char *)ext_acl;
 181
 182fail:
 183        kfree(ext_acl);
 184        return ERR_PTR(-EINVAL);
 185}
 186
 187/*
 188 * Inode operation get_posix_acl().
 189 *
 190 * inode->i_mutex: down
 191 * BKL held [before 2.5.x]
 192 */
 193struct posix_acl *reiserfs_get_acl(struct inode *inode, int type, bool rcu)
 194{
 195        char *name, *value;
 196        struct posix_acl *acl;
 197        int size;
 198        int retval;
 199
 200        if (rcu)
 201                return ERR_PTR(-ECHILD);
 202
 203        switch (type) {
 204        case ACL_TYPE_ACCESS:
 205                name = XATTR_NAME_POSIX_ACL_ACCESS;
 206                break;
 207        case ACL_TYPE_DEFAULT:
 208                name = XATTR_NAME_POSIX_ACL_DEFAULT;
 209                break;
 210        default:
 211                BUG();
 212        }
 213
 214        size = reiserfs_xattr_get(inode, name, NULL, 0);
 215        if (size < 0) {
 216                if (size == -ENODATA || size == -ENOSYS)
 217                        return NULL;
 218                return ERR_PTR(size);
 219        }
 220
 221        value = kmalloc(size, GFP_NOFS);
 222        if (!value)
 223                return ERR_PTR(-ENOMEM);
 224
 225        retval = reiserfs_xattr_get(inode, name, value, size);
 226        if (retval == -ENODATA || retval == -ENOSYS) {
 227                /*
 228                 * This shouldn't actually happen as it should have
 229                 * been caught above.. but just in case
 230                 */
 231                acl = NULL;
 232        } else if (retval < 0) {
 233                acl = ERR_PTR(retval);
 234        } else {
 235                acl = reiserfs_posix_acl_from_disk(value, retval);
 236        }
 237
 238        kfree(value);
 239        return acl;
 240}
 241
 242/*
 243 * Inode operation set_posix_acl().
 244 *
 245 * inode->i_mutex: down
 246 * BKL held [before 2.5.x]
 247 */
 248static int
 249__reiserfs_set_acl(struct reiserfs_transaction_handle *th, struct inode *inode,
 250                 int type, struct posix_acl *acl)
 251{
 252        char *name;
 253        void *value = NULL;
 254        size_t size = 0;
 255        int error;
 256
 257        switch (type) {
 258        case ACL_TYPE_ACCESS:
 259                name = XATTR_NAME_POSIX_ACL_ACCESS;
 260                break;
 261        case ACL_TYPE_DEFAULT:
 262                name = XATTR_NAME_POSIX_ACL_DEFAULT;
 263                if (!S_ISDIR(inode->i_mode))
 264                        return acl ? -EACCES : 0;
 265                break;
 266        default:
 267                return -EINVAL;
 268        }
 269
 270        if (acl) {
 271                value = reiserfs_posix_acl_to_disk(acl, &size);
 272                if (IS_ERR(value))
 273                        return (int)PTR_ERR(value);
 274        }
 275
 276        error = reiserfs_xattr_set_handle(th, inode, name, value, size, 0);
 277
 278        /*
 279         * Ensure that the inode gets dirtied if we're only using
 280         * the mode bits and an old ACL didn't exist. We don't need
 281         * to check if the inode is hashed here since we won't get
 282         * called by reiserfs_inherit_default_acl().
 283         */
 284        if (error == -ENODATA) {
 285                error = 0;
 286                if (type == ACL_TYPE_ACCESS) {
 287                        inode->i_ctime = current_time(inode);
 288                        mark_inode_dirty(inode);
 289                }
 290        }
 291
 292        kfree(value);
 293
 294        if (!error)
 295                set_cached_acl(inode, type, acl);
 296
 297        return error;
 298}
 299
 300/*
 301 * dir->i_mutex: locked,
 302 * inode is new and not released into the wild yet
 303 */
 304int
 305reiserfs_inherit_default_acl(struct reiserfs_transaction_handle *th,
 306                             struct inode *dir, struct dentry *dentry,
 307                             struct inode *inode)
 308{
 309        struct posix_acl *default_acl, *acl;
 310        int err = 0;
 311
 312        /* ACLs only get applied to files and directories */
 313        if (S_ISLNK(inode->i_mode))
 314                return 0;
 315
 316        /*
 317         * ACLs can only be used on "new" objects, so if it's an old object
 318         * there is nothing to inherit from
 319         */
 320        if (get_inode_sd_version(dir) == STAT_DATA_V1)
 321                goto apply_umask;
 322
 323        /*
 324         * Don't apply ACLs to objects in the .reiserfs_priv tree.. This
 325         * would be useless since permissions are ignored, and a pain because
 326         * it introduces locking cycles
 327         */
 328        if (IS_PRIVATE(inode))
 329                goto apply_umask;
 330
 331        err = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
 332        if (err)
 333                return err;
 334
 335        if (default_acl) {
 336                err = __reiserfs_set_acl(th, inode, ACL_TYPE_DEFAULT,
 337                                         default_acl);
 338                posix_acl_release(default_acl);
 339        }
 340        if (acl) {
 341                if (!err)
 342                        err = __reiserfs_set_acl(th, inode, ACL_TYPE_ACCESS,
 343                                                 acl);
 344                posix_acl_release(acl);
 345        }
 346
 347        return err;
 348
 349apply_umask:
 350        /* no ACL, apply umask */
 351        inode->i_mode &= ~current_umask();
 352        return err;
 353}
 354
 355/* This is used to cache the default acl before a new object is created.
 356 * The biggest reason for this is to get an idea of how many blocks will
 357 * actually be required for the create operation if we must inherit an ACL.
 358 * An ACL write can add up to 3 object creations and an additional file write
 359 * so we'd prefer not to reserve that many blocks in the journal if we can.
 360 * It also has the advantage of not loading the ACL with a transaction open,
 361 * this may seem silly, but if the owner of the directory is doing the
 362 * creation, the ACL may not be loaded since the permissions wouldn't require
 363 * it.
 364 * We return the number of blocks required for the transaction.
 365 */
 366int reiserfs_cache_default_acl(struct inode *inode)
 367{
 368        struct posix_acl *acl;
 369        int nblocks = 0;
 370
 371        if (IS_PRIVATE(inode))
 372                return 0;
 373
 374        acl = get_acl(inode, ACL_TYPE_DEFAULT);
 375
 376        if (acl && !IS_ERR(acl)) {
 377                int size = reiserfs_acl_size(acl->a_count);
 378
 379                /* Other xattrs can be created during inode creation. We don't
 380                 * want to claim too many blocks, so we check to see if we
 381                 * need to create the tree to the xattrs, and then we
 382                 * just want two files. */
 383                nblocks = reiserfs_xattr_jcreate_nblocks(inode);
 384                nblocks += JOURNAL_BLOCKS_PER_OBJECT(inode->i_sb);
 385
 386                REISERFS_I(inode)->i_flags |= i_has_xattr_dir;
 387
 388                /* We need to account for writes + bitmaps for two files */
 389                nblocks += reiserfs_xattr_nblocks(inode, size) * 4;
 390                posix_acl_release(acl);
 391        }
 392
 393        return nblocks;
 394}
 395
 396/*
 397 * Called under i_mutex
 398 */
 399int reiserfs_acl_chmod(struct inode *inode)
 400{
 401        if (IS_PRIVATE(inode))
 402                return 0;
 403        if (get_inode_sd_version(inode) == STAT_DATA_V1 ||
 404            !reiserfs_posixacl(inode->i_sb))
 405                return 0;
 406
 407        return posix_acl_chmod(&init_user_ns, inode, inode->i_mode);
 408}
 409