fs/ubifs/xattr.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * This file is part of UBIFS.
   4  *
   5  * Copyright (C) 2006-2008 Nokia Corporation.
   6  *
   7  * Authors: Artem Bityutskiy (Битюцкий Артём)
   8  *          Adrian Hunter
   9  */
  10
  11 /*
  12  * This file implements UBIFS extended attributes support.
  13  *
  14  * Extended attributes are implemented as regular inodes with attached data,
  15  * which limits extended attribute size to UBIFS block size (4KiB). Names of
  16  * extended attributes are described by extended attribute entries (xentries),
  17  * which are almost identical to directory entries, but have different key type.
  18  *
  19  * In other words, the situation with extended attributes is very similar to
  20  * directories. Indeed, any inode (but of course not xattr inodes) may have a
  21  * number of associated xentries, just like directory inodes have associated
  22  * directory entries. Extended attribute entries store the name of the extended
  23  * attribute, the host inode number, and the extended attribute inode number.
  24  * Similarly, direntries store the name, the parent and the target inode
  25  * numbers. Thus, most of the common UBIFS mechanisms may be re-used for
  26  * extended attributes.
  27  *
  28  * The number of extended attributes is not limited, but there is Linux
  29  * limitation on the maximum possible size of the list of all extended
  30  * attributes associated with an inode (%XATTR_LIST_MAX), so UBIFS makes sure
  31  * the sum of all extended attribute names of the inode does not exceed that
  32  * limit.
  33  *
  34  * Extended attributes are synchronous, which means they are written to the
  35  * flash media synchronously and there is no write-back for extended attribute
  36  * inodes. The extended attribute values are not stored in compressed form on
  37  * the media.
  38  *
  39  * Since extended attributes are represented by regular inodes, they are cached
  40  * in the VFS inode cache. The xentries are cached in the LNC cache (see
  41  * tnc.c).
  42  *
  43  * ACL support is not implemented.
  44  */
  45
  46 #include "ubifs.h"
  47 #include <linux/fs.h>
  48 #include <linux/slab.h>
  49 #include <linux/xattr.h>
  50
  51 /*
  52  * Extended attribute type constants.
  53  *
  54  * USER_XATTR: user extended attribute ("user.*")
  55  * TRUSTED_XATTR: trusted extended attribute ("trusted.*)
  56  * SECURITY_XATTR: security extended attribute ("security.*")
  57  */
  58 enum {
  59         USER_XATTR,
  60         TRUSTED_XATTR,
  61         SECURITY_XATTR,
  62 };
  63
  64 static const struct inode_operations empty_iops;
  65 static const struct file_operations empty_fops;
  66
  67 /**
  68  * create_xattr - create an extended attribute.
  69  * @c: UBIFS file-system description object
  70  * @host: host inode
  71  * @nm: extended attribute name
  72  * @value: extended attribute value
  73  * @size: size of extended attribute value
  74  *
  75  * This is a helper function which creates an extended attribute of name @nm
  76  * and value @value for inode @host. The host inode is also updated on flash
  77  * because the ctime and extended attribute accounting data changes. This
  78  * function returns zero in case of success and a negative error code in case
  79  * of failure.
  80  */
  81 static int create_xattr(struct ubifs_info *c, struct inode *host,
  82                         const struct fscrypt_name *nm, const void *value, int size)
  83 {
  84         int err, names_len;
  85         struct inode *inode;
  86         struct ubifs_inode *ui, *host_ui = ubifs_inode(host);
  87         struct ubifs_budget_req req = { .new_ino = 1, .new_dent = 1,
  88                                 .new_ino_d = ALIGN(size, 8), .dirtied_ino = 1,
  89                                 .dirtied_ino_d = ALIGN(host_ui->data_len, 8) };
  90
  91         if (host_ui->xattr_cnt >= ubifs_xattr_max_cnt(c)) {
  92                 ubifs_err(c, "inode %lu already has too many xattrs (%d), cannot create more",
  93                           host->i_ino, host_ui->xattr_cnt);
  94                 return -ENOSPC;
  95         }
  96         /*
  97          * Linux limits the maximum size of the extended attribute names list
  98          * to %XATTR_LIST_MAX. This means we should not allow creating more
  99          * extended attributes if the name list becomes larger. This limitation
 100          * is artificial for UBIFS, though.
 101          */
 102         names_len = host_ui->xattr_names + host_ui->xattr_cnt + fname_len(nm) + 1;
 103         if (names_len > XATTR_LIST_MAX) {
 104                 ubifs_err(c, "cannot add one more xattr name to inode %lu, total names length would become %d, max. is %d",
 105                           host->i_ino, names_len, XATTR_LIST_MAX);
 106                 return -ENOSPC;
 107         }
 108
 109         err = ubifs_budget_space(c, &req);
 110         if (err)
 111                 return err;
 112
 113         inode = ubifs_new_inode(c, host, S_IFREG | S_IRWXUGO, true);
 114         if (IS_ERR(inode)) {
 115                 err = PTR_ERR(inode);
 116                 goto out_budg;
 117         }
 118
 119         /* Re-define all operations to be "nothing" */
 120         inode->i_mapping->a_ops = &empty_aops;
 121         inode->i_op = &empty_iops;
 122         inode->i_fop = &empty_fops;
 123
 124         inode->i_flags |= S_SYNC | S_NOATIME | S_NOCMTIME;
 125         ui = ubifs_inode(inode);
 126         ui->xattr = 1;
 127         ui->flags |= UBIFS_XATTR_FL;
 128         ui->data = kmemdup(value, size, GFP_NOFS);
 129         if (!ui->data) {
 130                 err = -ENOMEM;
 131                 goto out_free;
 132         }
 133         inode->i_size = ui->ui_size = size;
 134         ui->data_len = size;
 135
 136         mutex_lock(&host_ui->ui_mutex);
 137         inode_set_ctime_current(host);
 138         host_ui->xattr_cnt += 1;
 139         host_ui->xattr_size += CALC_DENT_SIZE(fname_len(nm));
 140         host_ui->xattr_size += CALC_XATTR_BYTES(size);
 141         host_ui->xattr_names += fname_len(nm);
 142
 143         /*
 144          * We handle UBIFS_XATTR_NAME_ENCRYPTION_CONTEXT here because we
 145          * have to set the UBIFS_CRYPT_FL flag on the host inode.
 146          * To avoid multiple updates of the same inode in the same operation,
 147          * let's do it here.
 148          */
 149         if (strcmp(fname_name(nm), UBIFS_XATTR_NAME_ENCRYPTION_CONTEXT) == 0)
 150                 host_ui->flags |= UBIFS_CRYPT_FL;
 151
 152         err = ubifs_jnl_update(c, host, nm, inode, 0, 1, 0);
 153         if (err)
 154                 goto out_cancel;
 155         ubifs_set_inode_flags(host);
 156         mutex_unlock(&host_ui->ui_mutex);
 157
 158         ubifs_release_budget(c, &req);
 159         insert_inode_hash(inode);
 160         iput(inode);
 161         return 0;
 162
 163 out_cancel:
 164         host_ui->xattr_cnt -= 1;
 165         host_ui->xattr_size -= CALC_DENT_SIZE(fname_len(nm));
 166         host_ui->xattr_size -= CALC_XATTR_BYTES(size);
 167         host_ui->xattr_names -= fname_len(nm);
 168         host_ui->flags &= ~UBIFS_CRYPT_FL;
 169         mutex_unlock(&host_ui->ui_mutex);
 170 out_free:
 171         make_bad_inode(inode);
 172         iput(inode);
 173 out_budg:
 174         ubifs_release_budget(c, &req);
 175         return err;
 176 }
 177
 178 /**
 179  * change_xattr - change an extended attribute.
 180  * @c: UBIFS file-system description object
 181  * @host: host inode
 182  * @inode: extended attribute inode
 183  * @value: extended attribute value
 184  * @size: size of extended attribute value
 185  *
 186  * This helper function changes the value of extended attribute @inode with new
 187  * data from @value. Returns zero in case of success and a negative error code
 188  * in case of failure.
 189  */
 190 static int change_xattr(struct ubifs_info *c, struct inode *host,
 191                         struct inode *inode, const void *value, int size)
 192 {
 193         int err;
 194         struct ubifs_inode *host_ui = ubifs_inode(host);
 195         struct ubifs_inode *ui = ubifs_inode(inode);
 196         void *buf = NULL;
 197         int old_size;
 198         struct ubifs_budget_req req = { .dirtied_ino = 2,
 199                 .dirtied_ino_d = ALIGN(size, 8) + ALIGN(host_ui->data_len, 8) };
 200
 201         ubifs_assert(c, ui->data_len == inode->i_size);
 202         err = ubifs_budget_space(c, &req);
 203         if (err)
 204                 return err;
 205
 206         buf = kmemdup(value, size, GFP_NOFS);
 207         if (!buf) {
 208                 err = -ENOMEM;
 209                 goto out_free;
 210         }
 211         kfree(ui->data);
 212         ui->data = buf;
 213         inode->i_size = ui->ui_size = size;
 214         old_size = ui->data_len;
 215         ui->data_len = size;
 216
 217         mutex_lock(&host_ui->ui_mutex);
 218         inode_set_ctime_current(host);
 219         host_ui->xattr_size -= CALC_XATTR_BYTES(old_size);
 220         host_ui->xattr_size += CALC_XATTR_BYTES(size);
 221
 222         /*
 223          * It is important to write the host inode after the xattr inode
 224          * because if the host inode gets synchronized (via 'fsync()'), then
 225          * the extended attribute inode gets synchronized, because it goes
 226          * before the host inode in the write-buffer.
 227          */
 228         err = ubifs_jnl_change_xattr(c, inode, host);
 229         if (err)
 230                 goto out_cancel;
 231         mutex_unlock(&host_ui->ui_mutex);
 232
 233         ubifs_release_budget(c, &req);
 234         return 0;
 235
 236 out_cancel:
 237         host_ui->xattr_size -= CALC_XATTR_BYTES(size);
 238         host_ui->xattr_size += CALC_XATTR_BYTES(old_size);
 239         mutex_unlock(&host_ui->ui_mutex);
 240         make_bad_inode(inode);
 241 out_free:
 242         ubifs_release_budget(c, &req);
 243         return err;
 244 }
 245
 246 static struct inode *iget_xattr(struct ubifs_info *c, ino_t inum)
 247 {
 248         struct inode *inode;
 249
 250         inode = ubifs_iget(c->vfs_sb, inum);
 251         if (IS_ERR(inode)) {
 252                 ubifs_err(c, "dead extended attribute entry, error %d",
 253                           (int)PTR_ERR(inode));
 254                 return inode;
 255         }
 256         if (ubifs_inode(inode)->xattr)
 257                 return inode;
 258         ubifs_err(c, "corrupt extended attribute entry");
 259         iput(inode);
 260         return ERR_PTR(-EINVAL);
 261 }
 262
 263 int ubifs_xattr_set(struct inode *host, const char *name, const void *value,
 264                     size_t size, int flags, bool check_lock)
 265 {
 266         struct inode *inode;
 267         struct ubifs_info *c = host->i_sb->s_fs_info;
 268         struct fscrypt_name nm = { .disk_name = FSTR_INIT((char *)name, strlen(name))};
 269         struct ubifs_dent_node *xent;
 270         union ubifs_key key;
 271         int err;
 272
 273         if (check_lock)
 274                 ubifs_assert(c, inode_is_locked(host));
 275
 276         if (size > UBIFS_MAX_INO_DATA)
 277                 return -ERANGE;
 278
 279         if (fname_len(&nm) > UBIFS_MAX_NLEN)
 280                 return -ENAMETOOLONG;
 281
 282         xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS);
 283         if (!xent)
 284                 return -ENOMEM;
 285
 286         down_write(&ubifs_inode(host)->xattr_sem);
 287         /*
 288          * The extended attribute entries are stored in LNC, so multiple
 289          * look-ups do not involve reading the flash.
 290          */
 291         xent_key_init(c, &key, host->i_ino, &nm);
 292         err = ubifs_tnc_lookup_nm(c, &key, xent, &nm);
 293         if (err) {
 294                 if (err != -ENOENT)
 295                         goto out_free;
 296
 297                 if (flags & XATTR_REPLACE)
 298                         /* We are asked not to create the xattr */
 299                         err = -ENODATA;
 300                 else
 301                         err = create_xattr(c, host, &nm, value, size);
 302                 goto out_free;
 303         }
 304
 305         if (flags & XATTR_CREATE) {
 306                 /* We are asked not to replace the xattr */
 307                 err = -EEXIST;
 308                 goto out_free;
 309         }
 310
 311         inode = iget_xattr(c, le64_to_cpu(xent->inum));
 312         if (IS_ERR(inode)) {
 313                 err = PTR_ERR(inode);
 314                 goto out_free;
 315         }
 316
 317         err = change_xattr(c, host, inode, value, size);
 318         iput(inode);
 319
 320 out_free:
 321         up_write(&ubifs_inode(host)->xattr_sem);
 322         kfree(xent);
 323         return err;
 324 }
 325
 326 ssize_t ubifs_xattr_get(struct inode *host, const char *name, void *buf,
 327                         size_t size)
 328 {
 329         struct inode *inode;
 330         struct ubifs_info *c = host->i_sb->s_fs_info;
 331         struct fscrypt_name nm = { .disk_name = FSTR_INIT((char *)name, strlen(name))};
 332         struct ubifs_inode *ui;
 333         struct ubifs_dent_node *xent;
 334         union ubifs_key key;
 335         int err;
 336
 337         if (fname_len(&nm) > UBIFS_MAX_NLEN)
 338                 return -ENAMETOOLONG;
 339
 340         xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS);
 341         if (!xent)
 342                 return -ENOMEM;
 343
 344         down_read(&ubifs_inode(host)->xattr_sem);
 345         xent_key_init(c, &key, host->i_ino, &nm);
 346         err = ubifs_tnc_lookup_nm(c, &key, xent, &nm);
 347         if (err) {
 348                 if (err == -ENOENT)
 349                         err = -ENODATA;
 350                 goto out_cleanup;
 351         }
 352
 353         inode = iget_xattr(c, le64_to_cpu(xent->inum));
 354         if (IS_ERR(inode)) {
 355                 err = PTR_ERR(inode);
 356                 goto out_cleanup;
 357         }
 358
 359         ui = ubifs_inode(inode);
 360         ubifs_assert(c, inode->i_size == ui->data_len);
 361         ubifs_assert(c, ubifs_inode(host)->xattr_size > ui->data_len);
 362
 363         if (buf) {
 364                 /* If @buf is %NULL we are supposed to return the length */
 365                 if (ui->data_len > size) {
 366                         err = -ERANGE;
 367                         goto out_iput;
 368                 }
 369
 370                 memcpy(buf, ui->data, ui->data_len);
 371         }
 372         err = ui->data_len;
 373
 374 out_iput:
 375         iput(inode);
 376 out_cleanup:
 377         up_read(&ubifs_inode(host)->xattr_sem);
 378         kfree(xent);
 379         return err;
 380 }
 381
 382 static bool xattr_visible(const char *name)
 383 {
 384         /* File encryption related xattrs are for internal use only */
 385         if (strcmp(name, UBIFS_XATTR_NAME_ENCRYPTION_CONTEXT) == 0)
 386                 return false;
 387
 388         /* Show trusted namespace only for "power" users */
 389         if (strncmp(name, XATTR_TRUSTED_PREFIX,
 390                     XATTR_TRUSTED_PREFIX_LEN) == 0 && !capable(CAP_SYS_ADMIN))
 391                 return false;
 392
 393         return true;
 394 }
 395
 396 ssize_t ubifs_listxattr(struct dentry *dentry, char *buffer, size_t size)
 397 {
 398         union ubifs_key key;
 399         struct inode *host = d_inode(dentry);
 400         struct ubifs_info *c = host->i_sb->s_fs_info;
 401         struct ubifs_inode *host_ui = ubifs_inode(host);
 402         struct ubifs_dent_node *xent, *pxent = NULL;
 403         int err, len, written = 0;
 404         struct fscrypt_name nm = {0};
 405
 406         dbg_gen("ino %lu ('%pd'), buffer size %zd", host->i_ino,
 407                 dentry, size);
 408
 409         down_read(&host_ui->xattr_sem);
 410         len = host_ui->xattr_names + host_ui->xattr_cnt;
 411         if (!buffer) {
 412                 /*
 413                  * We should return the minimum buffer size which will fit a
 414                  * null-terminated list of all the extended attribute names.
 415                  */
 416                 err = len;
 417                 goto out_err;
 418         }
 419
 420         if (len > size) {
 421                 err = -ERANGE;
 422                 goto out_err;
 423         }
 424
 425         lowest_xent_key(c, &key, host->i_ino);
 426         while (1) {
 427                 xent = ubifs_tnc_next_ent(c, &key, &nm);
 428                 if (IS_ERR(xent)) {
 429                         err = PTR_ERR(xent);
 430                         break;
 431                 }
 432
 433                 fname_name(&nm) = xent->name;
 434                 fname_len(&nm) = le16_to_cpu(xent->nlen);
 435
 436                 if (xattr_visible(xent->name)) {
 437                         memcpy(buffer + written, fname_name(&nm), fname_len(&nm) + 1);
 438                         written += fname_len(&nm) + 1;
 439                 }
 440
 441                 kfree(pxent);
 442                 pxent = xent;
 443                 key_read(c, &xent->key, &key);
 444         }
 445         kfree(pxent);
 446         up_read(&host_ui->xattr_sem);
 447
 448         if (err != -ENOENT) {
 449                 ubifs_err(c, "cannot find next direntry, error %d", err);
 450                 return err;
 451         }
 452
 453         ubifs_assert(c, written <= size);
 454         return written;
 455
 456 out_err:
 457         up_read(&host_ui->xattr_sem);
 458         return err;
 459 }
 460
 461 static int remove_xattr(struct ubifs_info *c, struct inode *host,
 462                         struct inode *inode, const struct fscrypt_name *nm)
 463 {
 464         int err;
 465         struct ubifs_inode *host_ui = ubifs_inode(host);
 466         struct ubifs_inode *ui = ubifs_inode(inode);
 467         struct ubifs_budget_req req = { .dirtied_ino = 2, .mod_dent = 1,
 468                                 .dirtied_ino_d = ALIGN(host_ui->data_len, 8) };
 469
 470         ubifs_assert(c, ui->data_len == inode->i_size);
 471
 472         err = ubifs_budget_space(c, &req);
 473         if (err)
 474                 return err;
 475
 476         mutex_lock(&host_ui->ui_mutex);
 477         inode_set_ctime_current(host);
 478         host_ui->xattr_cnt -= 1;
 479         host_ui->xattr_size -= CALC_DENT_SIZE(fname_len(nm));
 480         host_ui->xattr_size -= CALC_XATTR_BYTES(ui->data_len);
 481         host_ui->xattr_names -= fname_len(nm);
 482
 483         err = ubifs_jnl_delete_xattr(c, host, inode, nm);
 484         if (err)
 485                 goto out_cancel;
 486         mutex_unlock(&host_ui->ui_mutex);
 487
 488         ubifs_release_budget(c, &req);
 489         return 0;
 490
 491 out_cancel:
 492         host_ui->xattr_cnt += 1;
 493         host_ui->xattr_size += CALC_DENT_SIZE(fname_len(nm));
 494         host_ui->xattr_size += CALC_XATTR_BYTES(ui->data_len);
 495         host_ui->xattr_names += fname_len(nm);
 496         mutex_unlock(&host_ui->ui_mutex);
 497         ubifs_release_budget(c, &req);
 498         make_bad_inode(inode);
 499         return err;
 500 }
 501
 502 int ubifs_purge_xattrs(struct inode *host)
 503 {
 504         union ubifs_key key;
 505         struct ubifs_info *c = host->i_sb->s_fs_info;
 506         struct ubifs_dent_node *xent, *pxent = NULL;
 507         struct inode *xino;
 508         struct fscrypt_name nm = {0};
 509         int err;
 510
 511         if (ubifs_inode(host)->xattr_cnt <= ubifs_xattr_max_cnt(c))
 512                 return 0;
 513
 514         ubifs_warn(c, "inode %lu has too many xattrs, doing a non-atomic deletion",
 515                    host->i_ino);
 516
 517         down_write(&ubifs_inode(host)->xattr_sem);
 518         lowest_xent_key(c, &key, host->i_ino);
 519         while (1) {
 520                 xent = ubifs_tnc_next_ent(c, &key, &nm);
 521                 if (IS_ERR(xent)) {
 522                         err = PTR_ERR(xent);
 523                         break;
 524                 }
 525
 526                 fname_name(&nm) = xent->name;
 527                 fname_len(&nm) = le16_to_cpu(xent->nlen);
 528
 529                 xino = ubifs_iget(c->vfs_sb, le64_to_cpu(xent->inum));
 530                 if (IS_ERR(xino)) {
 531                         err = PTR_ERR(xino);
 532                         ubifs_err(c, "dead directory entry '%s', error %d",
 533                                   xent->name, err);
 534                         ubifs_ro_mode(c, err);
 535                         kfree(pxent);
 536                         kfree(xent);
 537                         goto out_err;
 538                 }
 539
 540                 ubifs_assert(c, ubifs_inode(xino)->xattr);
 541
 542                 clear_nlink(xino);
 543                 err = remove_xattr(c, host, xino, &nm);
 544                 if (err) {
 545                         kfree(pxent);
 546                         kfree(xent);
 547                         iput(xino);
 548                         ubifs_err(c, "cannot remove xattr, error %d", err);
 549                         goto out_err;
 550                 }
 551
 552                 iput(xino);
 553
 554                 kfree(pxent);
 555                 pxent = xent;
 556                 key_read(c, &xent->key, &key);
 557         }
 558         kfree(pxent);
 559         up_write(&ubifs_inode(host)->xattr_sem);
 560
 561         if (err != -ENOENT) {
 562                 ubifs_err(c, "cannot find next direntry, error %d", err);
 563                 return err;
 564         }
 565
 566         return 0;
 567
 568 out_err:
 569         up_write(&ubifs_inode(host)->xattr_sem);
 570         return err;
 571 }
 572
 573 /**
 574  * ubifs_evict_xattr_inode - Evict an xattr inode.
 575  * @c: UBIFS file-system description object
 576  * @xattr_inum: xattr inode number
 577  *
 578  * When an inode that hosts xattrs is being removed we have to make sure
 579  * that cached inodes of the xattrs also get removed from the inode cache
 580  * otherwise we'd waste memory. This function looks up an inode from the
 581  * inode cache and clears the link counter such that iput() will evict
 582  * the inode.
 583  */
 584 void ubifs_evict_xattr_inode(struct ubifs_info *c, ino_t xattr_inum)
 585 {
 586         struct inode *inode;
 587
 588         inode = ilookup(c->vfs_sb, xattr_inum);
 589         if (inode) {
 590                 clear_nlink(inode);
 591                 iput(inode);
 592         }
 593 }
 594
 595 static int ubifs_xattr_remove(struct inode *host, const char *name)
 596 {
 597         struct inode *inode;
 598         struct ubifs_info *c = host->i_sb->s_fs_info;
 599         struct fscrypt_name nm = { .disk_name = FSTR_INIT((char *)name, strlen(name))};
 600         struct ubifs_dent_node *xent;
 601         union ubifs_key key;
 602         int err;
 603
 604         ubifs_assert(c, inode_is_locked(host));
 605
 606         if (fname_len(&nm) > UBIFS_MAX_NLEN)
 607                 return -ENAMETOOLONG;
 608
 609         xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS);
 610         if (!xent)
 611                 return -ENOMEM;
 612
 613         down_write(&ubifs_inode(host)->xattr_sem);
 614         xent_key_init(c, &key, host->i_ino, &nm);
 615         err = ubifs_tnc_lookup_nm(c, &key, xent, &nm);
 616         if (err) {
 617                 if (err == -ENOENT)
 618                         err = -ENODATA;
 619                 goto out_free;
 620         }
 621
 622         inode = iget_xattr(c, le64_to_cpu(xent->inum));
 623         if (IS_ERR(inode)) {
 624                 err = PTR_ERR(inode);
 625                 goto out_free;
 626         }
 627
 628         ubifs_assert(c, inode->i_nlink == 1);
 629         clear_nlink(inode);
 630         err = remove_xattr(c, host, inode, &nm);
 631         if (err)
 632                 set_nlink(inode, 1);
 633
 634         /* If @i_nlink is 0, 'iput()' will delete the inode */
 635         iput(inode);
 636
 637 out_free:
 638         up_write(&ubifs_inode(host)->xattr_sem);
 639         kfree(xent);
 640         return err;
 641 }
 642
 643 #ifdef CONFIG_UBIFS_FS_SECURITY
 644 static int init_xattrs(struct inode *inode, const struct xattr *xattr_array,
 645                       void *fs_info)
 646 {
 647         const struct xattr *xattr;
 648         char *name;
 649         int err = 0;
 650
 651         for (xattr = xattr_array; xattr->name != NULL; xattr++) {
 652                 name = kmalloc(XATTR_SECURITY_PREFIX_LEN +
 653                                strlen(xattr->name) + 1, GFP_NOFS);
 654                 if (!name) {
 655                         err = -ENOMEM;
 656                         break;
 657                 }
 658                 strcpy(name, XATTR_SECURITY_PREFIX);
 659                 strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name);
 660                 /*
 661                  * creating a new inode without holding the inode rwsem,
 662                  * no need to check whether inode is locked.
 663                  */
 664                 err = ubifs_xattr_set(inode, name, xattr->value,
 665                                       xattr->value_len, 0, false);
 666                 kfree(name);
 667                 if (err < 0)
 668                         break;
 669         }
 670
 671         return err;
 672 }
 673
 674 int ubifs_init_security(struct inode *dentry, struct inode *inode,
 675                         const struct qstr *qstr)
 676 {
 677         int err;
 678
 679         err = security_inode_init_security(inode, dentry, qstr,
 680                                            &init_xattrs, NULL);
 681         if (err) {
 682                 struct ubifs_info *c = dentry->i_sb->s_fs_info;
 683                 ubifs_err(c, "cannot initialize security for inode %lu, error %d",
 684                           inode->i_ino, err);
 685         }
 686         return err;
 687 }
 688 #endif
 689
 690 static int xattr_get(const struct xattr_handler *handler,
 691                            struct dentry *dentry, struct inode *inode,
 692                            const char *name, void *buffer, size_t size)
 693 {
 694         dbg_gen("xattr '%s', ino %lu ('%pd'), buf size %zd", name,
 695                 inode->i_ino, dentry, size);
 696
 697         name = xattr_full_name(handler, name);
 698         return ubifs_xattr_get(inode, name, buffer, size);
 699 }
 700
 701 static int xattr_set(const struct xattr_handler *handler,
 702                            struct mnt_idmap *idmap,
 703                            struct dentry *dentry, struct inode *inode,
 704                            const char *name, const void *value,
 705                            size_t size, int flags)
 706 {
 707         dbg_gen("xattr '%s', host ino %lu ('%pd'), size %zd",
 708                 name, inode->i_ino, dentry, size);
 709
 710         name = xattr_full_name(handler, name);
 711
 712         if (value)
 713                 return ubifs_xattr_set(inode, name, value, size, flags, true);
 714         else
 715                 return ubifs_xattr_remove(inode, name);
 716 }
 717
 718 static const struct xattr_handler ubifs_user_xattr_handler = {
 719         .prefix = XATTR_USER_PREFIX,
 720         .get = xattr_get,
 721         .set = xattr_set,
 722 };
 723
 724 static const struct xattr_handler ubifs_trusted_xattr_handler = {
 725         .prefix = XATTR_TRUSTED_PREFIX,
 726         .get = xattr_get,
 727         .set = xattr_set,
 728 };
 729
 730 #ifdef CONFIG_UBIFS_FS_SECURITY
 731 static const struct xattr_handler ubifs_security_xattr_handler = {
 732         .prefix = XATTR_SECURITY_PREFIX,
 733         .get = xattr_get,
 734         .set = xattr_set,
 735 };
 736 #endif
 737
 738 const struct xattr_handler * const ubifs_xattr_handlers[] = {
 739         &ubifs_user_xattr_handler,
 740         &ubifs_trusted_xattr_handler,
 741 #ifdef CONFIG_UBIFS_FS_SECURITY
 742         &ubifs_security_xattr_handler,
 743 #endif
 744         NULL
 745 };