fs/f2fs/xattr.c

   1 /*
   2  * fs/f2fs/xattr.c
   3  *
   4  * Copyright (c) 2012 Samsung Electronics Co., Ltd.
   5  *             http://www.samsung.com/
   6  *
   7  * Portions of this code from linux/fs/ext2/xattr.c
   8  *
   9  * Copyright (C) 2001-2003 Andreas Gruenbacher <agruen@suse.de>
  10  *
  11  * Fix by Harrison Xing <harrison@mountainviewdata.com>.
  12  * Extended attributes for symlinks and special files added per
  13  *  suggestion of Luka Renko <luka.renko@hermes.si>.
  14  * xattr consolidation Copyright (c) 2004 James Morris <jmorris@redhat.com>,
  15  *  Red Hat Inc.
  16  *
  17  * This program is free software; you can redistribute it and/or modify
  18  * it under the terms of the GNU General Public License version 2 as
  19  * published by the Free Software Foundation.
  20  */
  21 #include <linux/rwsem.h>
  22 #include <linux/f2fs_fs.h>
  23 #include <linux/security.h>
  24 #include <linux/posix_acl_xattr.h>
  25 #include "f2fs.h"
  26 #include "xattr.h"
  27
  28 static int f2fs_xattr_generic_get(const struct xattr_handler *handler,
  29                 struct dentry *dentry, const char *name, void *buffer,
  30                 size_t size)
  31 {
  32         struct f2fs_sb_info *sbi = F2FS_SB(dentry->d_sb);
  33
  34         switch (handler->flags) {
  35         case F2FS_XATTR_INDEX_USER:
  36                 if (!test_opt(sbi, XATTR_USER))
  37                         return -EOPNOTSUPP;
  38                 break;
  39         case F2FS_XATTR_INDEX_TRUSTED:
  40                 if (!capable(CAP_SYS_ADMIN))
  41                         return -EPERM;
  42                 break;
  43         case F2FS_XATTR_INDEX_SECURITY:
  44                 break;
  45         default:
  46                 return -EINVAL;
  47         }
  48         return f2fs_getxattr(d_inode(dentry), handler->flags, name,
  49                              buffer, size, NULL);
  50 }
  51
  52 static int f2fs_xattr_generic_set(const struct xattr_handler *handler,
  53                 struct dentry *dentry, const char *name, const void *value,
  54                 size_t size, int flags)
  55 {
  56         struct f2fs_sb_info *sbi = F2FS_SB(dentry->d_sb);
  57
  58         switch (handler->flags) {
  59         case F2FS_XATTR_INDEX_USER:
  60                 if (!test_opt(sbi, XATTR_USER))
  61                         return -EOPNOTSUPP;
  62                 break;
  63         case F2FS_XATTR_INDEX_TRUSTED:
  64                 if (!capable(CAP_SYS_ADMIN))
  65                         return -EPERM;
  66                 break;
  67         case F2FS_XATTR_INDEX_SECURITY:
  68                 break;
  69         default:
  70                 return -EINVAL;
  71         }
  72         return f2fs_setxattr(d_inode(dentry), handler->flags, name,
  73                                         value, size, NULL, flags);
  74 }
  75
  76 static bool f2fs_xattr_user_list(struct dentry *dentry)
  77 {
  78         struct f2fs_sb_info *sbi = F2FS_SB(dentry->d_sb);
  79
  80         return test_opt(sbi, XATTR_USER);
  81 }
  82
  83 static bool f2fs_xattr_trusted_list(struct dentry *dentry)
  84 {
  85         return capable(CAP_SYS_ADMIN);
  86 }
  87
  88 static int f2fs_xattr_advise_get(const struct xattr_handler *handler,
  89                 struct dentry *dentry, const char *name, void *buffer,
  90                 size_t size)
  91 {
  92         struct inode *inode = d_inode(dentry);
  93
  94         if (buffer)
  95                 *((char *)buffer) = F2FS_I(inode)->i_advise;
  96         return sizeof(char);
  97 }
  98
  99 static int f2fs_xattr_advise_set(const struct xattr_handler *handler,
 100                 struct dentry *dentry, const char *name, const void *value,
 101                 size_t size, int flags)
 102 {
 103         struct inode *inode = d_inode(dentry);
 104
 105         if (!inode_owner_or_capable(inode))
 106                 return -EPERM;
 107         if (value == NULL)
 108                 return -EINVAL;
 109
 110         F2FS_I(inode)->i_advise |= *(char *)value;
 111         mark_inode_dirty(inode);
 112         return 0;
 113 }
 114
 115 #ifdef CONFIG_F2FS_FS_SECURITY
 116 static int f2fs_initxattrs(struct inode *inode, const struct xattr *xattr_array,
 117                 void *page)
 118 {
 119         const struct xattr *xattr;
 120         int err = 0;
 121
 122         for (xattr = xattr_array; xattr->name != NULL; xattr++) {
 123                 err = f2fs_setxattr(inode, F2FS_XATTR_INDEX_SECURITY,
 124                                 xattr->name, xattr->value,
 125                                 xattr->value_len, (struct page *)page, 0);
 126                 if (err < 0)
 127                         break;
 128         }
 129         return err;
 130 }
 131
 132 int f2fs_init_security(struct inode *inode, struct inode *dir,
 133                                 const struct qstr *qstr, struct page *ipage)
 134 {
 135         return security_inode_init_security(inode, dir, qstr,
 136                                 &f2fs_initxattrs, ipage);
 137 }
 138 #endif
 139
 140 const struct xattr_handler f2fs_xattr_user_handler = {
 141         .prefix = XATTR_USER_PREFIX,
 142         .flags  = F2FS_XATTR_INDEX_USER,
 143         .list   = f2fs_xattr_user_list,
 144         .get    = f2fs_xattr_generic_get,
 145         .set    = f2fs_xattr_generic_set,
 146 };
 147
 148 const struct xattr_handler f2fs_xattr_trusted_handler = {
 149         .prefix = XATTR_TRUSTED_PREFIX,
 150         .flags  = F2FS_XATTR_INDEX_TRUSTED,
 151         .list   = f2fs_xattr_trusted_list,
 152         .get    = f2fs_xattr_generic_get,
 153         .set    = f2fs_xattr_generic_set,
 154 };
 155
 156 const struct xattr_handler f2fs_xattr_advise_handler = {
 157         .name   = F2FS_SYSTEM_ADVISE_NAME,
 158         .flags  = F2FS_XATTR_INDEX_ADVISE,
 159         .get    = f2fs_xattr_advise_get,
 160         .set    = f2fs_xattr_advise_set,
 161 };
 162
 163 const struct xattr_handler f2fs_xattr_security_handler = {
 164         .prefix = XATTR_SECURITY_PREFIX,
 165         .flags  = F2FS_XATTR_INDEX_SECURITY,
 166         .get    = f2fs_xattr_generic_get,
 167         .set    = f2fs_xattr_generic_set,
 168 };
 169
 170 static const struct xattr_handler *f2fs_xattr_handler_map[] = {
 171         [F2FS_XATTR_INDEX_USER] = &f2fs_xattr_user_handler,
 172 #ifdef CONFIG_F2FS_FS_POSIX_ACL
 173         [F2FS_XATTR_INDEX_POSIX_ACL_ACCESS] = &posix_acl_access_xattr_handler,
 174         [F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT] = &posix_acl_default_xattr_handler,
 175 #endif
 176         [F2FS_XATTR_INDEX_TRUSTED] = &f2fs_xattr_trusted_handler,
 177 #ifdef CONFIG_F2FS_FS_SECURITY
 178         [F2FS_XATTR_INDEX_SECURITY] = &f2fs_xattr_security_handler,
 179 #endif
 180         [F2FS_XATTR_INDEX_ADVISE] = &f2fs_xattr_advise_handler,
 181 };
 182
 183 const struct xattr_handler *f2fs_xattr_handlers[] = {
 184         &f2fs_xattr_user_handler,
 185 #ifdef CONFIG_F2FS_FS_POSIX_ACL
 186         &posix_acl_access_xattr_handler,
 187         &posix_acl_default_xattr_handler,
 188 #endif
 189         &f2fs_xattr_trusted_handler,
 190 #ifdef CONFIG_F2FS_FS_SECURITY
 191         &f2fs_xattr_security_handler,
 192 #endif
 193         &f2fs_xattr_advise_handler,
 194         NULL,
 195 };
 196
 197 static inline const struct xattr_handler *f2fs_xattr_handler(int index)
 198 {
 199         const struct xattr_handler *handler = NULL;
 200
 201         if (index > 0 && index < ARRAY_SIZE(f2fs_xattr_handler_map))
 202                 handler = f2fs_xattr_handler_map[index];
 203         return handler;
 204 }
 205
 206 static struct f2fs_xattr_entry *__find_xattr(void *base_addr, int index,
 207                                         size_t len, const char *name)
 208 {
 209         struct f2fs_xattr_entry *entry;
 210
 211         list_for_each_xattr(entry, base_addr) {
 212                 if (entry->e_name_index != index)
 213                         continue;
 214                 if (entry->e_name_len != len)
 215                         continue;
 216                 if (!memcmp(entry->e_name, name, len))
 217                         break;
 218         }
 219         return entry;
 220 }
 221
 222 static void *read_all_xattrs(struct inode *inode, struct page *ipage)
 223 {
 224         struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 225         struct f2fs_xattr_header *header;
 226         size_t size = PAGE_SIZE, inline_size = 0;
 227         void *txattr_addr;
 228
 229         inline_size = inline_xattr_size(inode);
 230
 231         txattr_addr = kzalloc(inline_size + size, GFP_F2FS_ZERO);
 232         if (!txattr_addr)
 233                 return NULL;
 234
 235         /* read from inline xattr */
 236         if (inline_size) {
 237                 struct page *page = NULL;
 238                 void *inline_addr;
 239
 240                 if (ipage) {
 241                         inline_addr = inline_xattr_addr(ipage);
 242                 } else {
 243                         page = get_node_page(sbi, inode->i_ino);
 244                         if (IS_ERR(page))
 245                                 goto fail;
 246                         inline_addr = inline_xattr_addr(page);
 247                 }
 248                 memcpy(txattr_addr, inline_addr, inline_size);
 249                 f2fs_put_page(page, 1);
 250         }
 251
 252         /* read from xattr node block */
 253         if (F2FS_I(inode)->i_xattr_nid) {
 254                 struct page *xpage;
 255                 void *xattr_addr;
 256
 257                 /* The inode already has an extended attribute block. */
 258                 xpage = get_node_page(sbi, F2FS_I(inode)->i_xattr_nid);
 259                 if (IS_ERR(xpage))
 260                         goto fail;
 261
 262                 xattr_addr = page_address(xpage);
 263                 memcpy(txattr_addr + inline_size, xattr_addr, PAGE_SIZE);
 264                 f2fs_put_page(xpage, 1);
 265         }
 266
 267         header = XATTR_HDR(txattr_addr);
 268
 269         /* never been allocated xattrs */
 270         if (le32_to_cpu(header->h_magic) != F2FS_XATTR_MAGIC) {
 271                 header->h_magic = cpu_to_le32(F2FS_XATTR_MAGIC);
 272                 header->h_refcount = cpu_to_le32(1);
 273         }
 274         return txattr_addr;
 275 fail:
 276         kzfree(txattr_addr);
 277         return NULL;
 278 }
 279
 280 static inline int write_all_xattrs(struct inode *inode, __u32 hsize,
 281                                 void *txattr_addr, struct page *ipage)
 282 {
 283         struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 284         size_t inline_size = 0;
 285         void *xattr_addr;
 286         struct page *xpage;
 287         nid_t new_nid = 0;
 288         int err;
 289
 290         inline_size = inline_xattr_size(inode);
 291
 292         if (hsize > inline_size && !F2FS_I(inode)->i_xattr_nid)
 293                 if (!alloc_nid(sbi, &new_nid))
 294                         return -ENOSPC;
 295
 296         /* write to inline xattr */
 297         if (inline_size) {
 298                 struct page *page = NULL;
 299                 void *inline_addr;
 300
 301                 if (ipage) {
 302                         inline_addr = inline_xattr_addr(ipage);
 303                         f2fs_wait_on_page_writeback(ipage, NODE, true);
 304                 } else {
 305                         page = get_node_page(sbi, inode->i_ino);
 306                         if (IS_ERR(page)) {
 307                                 alloc_nid_failed(sbi, new_nid);
 308                                 return PTR_ERR(page);
 309                         }
 310                         inline_addr = inline_xattr_addr(page);
 311                         f2fs_wait_on_page_writeback(page, NODE, true);
 312                 }
 313                 memcpy(inline_addr, txattr_addr, inline_size);
 314                 f2fs_put_page(page, 1);
 315
 316                 /* no need to use xattr node block */
 317                 if (hsize <= inline_size) {
 318                         err = truncate_xattr_node(inode, ipage);
 319                         alloc_nid_failed(sbi, new_nid);
 320                         return err;
 321                 }
 322         }
 323
 324         /* write to xattr node block */
 325         if (F2FS_I(inode)->i_xattr_nid) {
 326                 xpage = get_node_page(sbi, F2FS_I(inode)->i_xattr_nid);
 327                 if (IS_ERR(xpage)) {
 328                         alloc_nid_failed(sbi, new_nid);
 329                         return PTR_ERR(xpage);
 330                 }
 331                 f2fs_bug_on(sbi, new_nid);
 332                 f2fs_wait_on_page_writeback(xpage, NODE, true);
 333         } else {
 334                 struct dnode_of_data dn;
 335                 set_new_dnode(&dn, inode, NULL, NULL, new_nid);
 336                 xpage = new_node_page(&dn, XATTR_NODE_OFFSET, ipage);
 337                 if (IS_ERR(xpage)) {
 338                         alloc_nid_failed(sbi, new_nid);
 339                         return PTR_ERR(xpage);
 340                 }
 341                 alloc_nid_done(sbi, new_nid);
 342         }
 343
 344         xattr_addr = page_address(xpage);
 345         memcpy(xattr_addr, txattr_addr + inline_size, PAGE_SIZE -
 346                                                 sizeof(struct node_footer));
 347         set_page_dirty(xpage);
 348         f2fs_put_page(xpage, 1);
 349
 350         /* need to checkpoint during fsync */
 351         F2FS_I(inode)->xattr_ver = cur_cp_version(F2FS_CKPT(sbi));
 352         return 0;
 353 }
 354
 355 int f2fs_getxattr(struct inode *inode, int index, const char *name,
 356                 void *buffer, size_t buffer_size, struct page *ipage)
 357 {
 358         struct f2fs_xattr_entry *entry;
 359         void *base_addr;
 360         int error = 0;
 361         size_t size, len;
 362
 363         if (name == NULL)
 364                 return -EINVAL;
 365
 366         len = strlen(name);
 367         if (len > F2FS_NAME_LEN)
 368                 return -ERANGE;
 369
 370         base_addr = read_all_xattrs(inode, ipage);
 371         if (!base_addr)
 372                 return -ENOMEM;
 373
 374         entry = __find_xattr(base_addr, index, len, name);
 375         if (IS_XATTR_LAST_ENTRY(entry)) {
 376                 error = -ENODATA;
 377                 goto cleanup;
 378         }
 379
 380         size = le16_to_cpu(entry->e_value_size);
 381
 382         if (buffer && size > buffer_size) {
 383                 error = -ERANGE;
 384                 goto cleanup;
 385         }
 386
 387         if (buffer) {
 388                 char *pval = entry->e_name + entry->e_name_len;
 389                 memcpy(buffer, pval, size);
 390         }
 391         error = size;
 392
 393 cleanup:
 394         kzfree(base_addr);
 395         return error;
 396 }
 397
 398 ssize_t f2fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
 399 {
 400         struct inode *inode = d_inode(dentry);
 401         struct f2fs_xattr_entry *entry;
 402         void *base_addr;
 403         int error = 0;
 404         size_t rest = buffer_size;
 405
 406         base_addr = read_all_xattrs(inode, NULL);
 407         if (!base_addr)
 408                 return -ENOMEM;
 409
 410         list_for_each_xattr(entry, base_addr) {
 411                 const struct xattr_handler *handler =
 412                         f2fs_xattr_handler(entry->e_name_index);
 413                 const char *prefix;
 414                 size_t prefix_len;
 415                 size_t size;
 416
 417                 if (!handler || (handler->list && !handler->list(dentry)))
 418                         continue;
 419
 420                 prefix = handler->prefix ?: handler->name;
 421                 prefix_len = strlen(prefix);
 422                 size = prefix_len + entry->e_name_len + 1;
 423                 if (buffer) {
 424                         if (size > rest) {
 425                                 error = -ERANGE;
 426                                 goto cleanup;
 427                         }
 428                         memcpy(buffer, prefix, prefix_len);
 429                         buffer += prefix_len;
 430                         memcpy(buffer, entry->e_name, entry->e_name_len);
 431                         buffer += entry->e_name_len;
 432                         *buffer++ = 0;
 433                 }
 434                 rest -= size;
 435         }
 436         error = buffer_size - rest;
 437 cleanup:
 438         kzfree(base_addr);
 439         return error;
 440 }
 441
 442 static int __f2fs_setxattr(struct inode *inode, int index,
 443                         const char *name, const void *value, size_t size,
 444                         struct page *ipage, int flags)
 445 {
 446         struct f2fs_inode_info *fi = F2FS_I(inode);
 447         struct f2fs_xattr_entry *here, *last;
 448         void *base_addr;
 449         int found, newsize;
 450         size_t len;
 451         __u32 new_hsize;
 452         int error = -ENOMEM;
 453
 454         if (name == NULL)
 455                 return -EINVAL;
 456
 457         if (value == NULL)
 458                 size = 0;
 459
 460         len = strlen(name);
 461
 462         if (len > F2FS_NAME_LEN)
 463                 return -ERANGE;
 464
 465         if (size > MAX_VALUE_LEN(inode))
 466                 return -E2BIG;
 467
 468         base_addr = read_all_xattrs(inode, ipage);
 469         if (!base_addr)
 470                 goto exit;
 471
 472         /* find entry with wanted name. */
 473         here = __find_xattr(base_addr, index, len, name);
 474
 475         found = IS_XATTR_LAST_ENTRY(here) ? 0 : 1;
 476
 477         if ((flags & XATTR_REPLACE) && !found) {
 478                 error = -ENODATA;
 479                 goto exit;
 480         } else if ((flags & XATTR_CREATE) && found) {
 481                 error = -EEXIST;
 482                 goto exit;
 483         }
 484
 485         last = here;
 486         while (!IS_XATTR_LAST_ENTRY(last))
 487                 last = XATTR_NEXT_ENTRY(last);
 488
 489         newsize = XATTR_ALIGN(sizeof(struct f2fs_xattr_entry) + len + size);
 490
 491         /* 1. Check space */
 492         if (value) {
 493                 int free;
 494                 /*
 495                  * If value is NULL, it is remove operation.
 496                  * In case of update operation, we calculate free.
 497                  */
 498                 free = MIN_OFFSET(inode) - ((char *)last - (char *)base_addr);
 499                 if (found)
 500                         free = free + ENTRY_SIZE(here);
 501
 502                 if (unlikely(free < newsize)) {
 503                         error = -ENOSPC;
 504                         goto exit;
 505                 }
 506         }
 507
 508         /* 2. Remove old entry */
 509         if (found) {
 510                 /*
 511                  * If entry is found, remove old entry.
 512                  * If not found, remove operation is not needed.
 513                  */
 514                 struct f2fs_xattr_entry *next = XATTR_NEXT_ENTRY(here);
 515                 int oldsize = ENTRY_SIZE(here);
 516
 517                 memmove(here, next, (char *)last - (char *)next);
 518                 last = (struct f2fs_xattr_entry *)((char *)last - oldsize);
 519                 memset(last, 0, oldsize);
 520         }
 521
 522         new_hsize = (char *)last - (char *)base_addr;
 523
 524         /* 3. Write new entry */
 525         if (value) {
 526                 char *pval;
 527                 /*
 528                  * Before we come here, old entry is removed.
 529                  * We just write new entry.
 530                  */
 531                 memset(last, 0, newsize);
 532                 last->e_name_index = index;
 533                 last->e_name_len = len;
 534                 memcpy(last->e_name, name, len);
 535                 pval = last->e_name + len;
 536                 memcpy(pval, value, size);
 537                 last->e_value_size = cpu_to_le16(size);
 538                 new_hsize += newsize;
 539         }
 540
 541         error = write_all_xattrs(inode, new_hsize, base_addr, ipage);
 542         if (error)
 543                 goto exit;
 544
 545         if (is_inode_flag_set(fi, FI_ACL_MODE)) {
 546                 inode->i_mode = fi->i_acl_mode;
 547                 inode->i_ctime = CURRENT_TIME;
 548                 clear_inode_flag(fi, FI_ACL_MODE);
 549         }
 550         if (index == F2FS_XATTR_INDEX_ENCRYPTION &&
 551                         !strcmp(name, F2FS_XATTR_NAME_ENCRYPTION_CONTEXT))
 552                 f2fs_set_encrypted_inode(inode);
 553
 554         if (ipage)
 555                 update_inode(inode, ipage);
 556         else
 557                 update_inode_page(inode);
 558 exit:
 559         kzfree(base_addr);
 560         return error;
 561 }
 562
 563 int f2fs_setxattr(struct inode *inode, int index, const char *name,
 564                                 const void *value, size_t size,
 565                                 struct page *ipage, int flags)
 566 {
 567         struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 568         int err;
 569
 570         /* this case is only from init_inode_metadata */
 571         if (ipage)
 572                 return __f2fs_setxattr(inode, index, name, value,
 573                                                 size, ipage, flags);
 574         f2fs_balance_fs(sbi, true);
 575
 576         f2fs_lock_op(sbi);
 577         /* protect xattr_ver */
 578         down_write(&F2FS_I(inode)->i_sem);
 579         err = __f2fs_setxattr(inode, index, name, value, size, ipage, flags);
 580         up_write(&F2FS_I(inode)->i_sem);
 581         f2fs_unlock_op(sbi);
 582
 583         f2fs_update_time(sbi, REQ_TIME);
 584         return err;
 585 }