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 *unused, struct inode *inode,
  30                 const char *name, void *buffer, size_t size)
  31 {
  32         struct f2fs_sb_info *sbi = F2FS_SB(inode->i_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(inode, handler->flags, name,
  49                              buffer, size, NULL);
  50 }
  51
  52 static int f2fs_xattr_generic_set(const struct xattr_handler *handler,
  53                 struct dentry *unused, struct inode *inode,
  54                 const char *name, const void *value,
  55                 size_t size, int flags)
  56 {
  57         struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
  58
  59         switch (handler->flags) {
  60         case F2FS_XATTR_INDEX_USER:
  61                 if (!test_opt(sbi, XATTR_USER))
  62                         return -EOPNOTSUPP;
  63                 break;
  64         case F2FS_XATTR_INDEX_TRUSTED:
  65                 if (!capable(CAP_SYS_ADMIN))
  66                         return -EPERM;
  67                 break;
  68         case F2FS_XATTR_INDEX_SECURITY:
  69                 break;
  70         default:
  71                 return -EINVAL;
  72         }
  73         return f2fs_setxattr(inode, handler->flags, name,
  74                                         value, size, NULL, flags);
  75 }
  76
  77 static bool f2fs_xattr_user_list(struct dentry *dentry)
  78 {
  79         struct f2fs_sb_info *sbi = F2FS_SB(dentry->d_sb);
  80
  81         return test_opt(sbi, XATTR_USER);
  82 }
  83
  84 static bool f2fs_xattr_trusted_list(struct dentry *dentry)
  85 {
  86         return capable(CAP_SYS_ADMIN);
  87 }
  88
  89 static int f2fs_xattr_advise_get(const struct xattr_handler *handler,
  90                 struct dentry *unused, struct inode *inode,
  91                 const char *name, void *buffer, size_t size)
  92 {
  93         if (buffer)
  94                 *((char *)buffer) = F2FS_I(inode)->i_advise;
  95         return sizeof(char);
  96 }
  97
  98 static int f2fs_xattr_advise_set(const struct xattr_handler *handler,
  99                 struct dentry *unused, struct inode *inode,
 100                 const char *name, const void *value,
 101                 size_t size, int flags)
 102 {
 103         if (!inode_owner_or_capable(inode))
 104                 return -EPERM;
 105         if (value == NULL)
 106                 return -EINVAL;
 107
 108         F2FS_I(inode)->i_advise |= *(char *)value;
 109         f2fs_mark_inode_dirty_sync(inode);
 110         return 0;
 111 }
 112
 113 #ifdef CONFIG_F2FS_FS_SECURITY
 114 static int f2fs_initxattrs(struct inode *inode, const struct xattr *xattr_array,
 115                 void *page)
 116 {
 117         const struct xattr *xattr;
 118         int err = 0;
 119
 120         for (xattr = xattr_array; xattr->name != NULL; xattr++) {
 121                 err = f2fs_setxattr(inode, F2FS_XATTR_INDEX_SECURITY,
 122                                 xattr->name, xattr->value,
 123                                 xattr->value_len, (struct page *)page, 0);
 124                 if (err < 0)
 125                         break;
 126         }
 127         return err;
 128 }
 129
 130 int f2fs_init_security(struct inode *inode, struct inode *dir,
 131                                 const struct qstr *qstr, struct page *ipage)
 132 {
 133         return security_inode_init_security(inode, dir, qstr,
 134                                 &f2fs_initxattrs, ipage);
 135 }
 136 #endif
 137
 138 const struct xattr_handler f2fs_xattr_user_handler = {
 139         .prefix = XATTR_USER_PREFIX,
 140         .flags  = F2FS_XATTR_INDEX_USER,
 141         .list   = f2fs_xattr_user_list,
 142         .get    = f2fs_xattr_generic_get,
 143         .set    = f2fs_xattr_generic_set,
 144 };
 145
 146 const struct xattr_handler f2fs_xattr_trusted_handler = {
 147         .prefix = XATTR_TRUSTED_PREFIX,
 148         .flags  = F2FS_XATTR_INDEX_TRUSTED,
 149         .list   = f2fs_xattr_trusted_list,
 150         .get    = f2fs_xattr_generic_get,
 151         .set    = f2fs_xattr_generic_set,
 152 };
 153
 154 const struct xattr_handler f2fs_xattr_advise_handler = {
 155         .name   = F2FS_SYSTEM_ADVISE_NAME,
 156         .flags  = F2FS_XATTR_INDEX_ADVISE,
 157         .get    = f2fs_xattr_advise_get,
 158         .set    = f2fs_xattr_advise_set,
 159 };
 160
 161 const struct xattr_handler f2fs_xattr_security_handler = {
 162         .prefix = XATTR_SECURITY_PREFIX,
 163         .flags  = F2FS_XATTR_INDEX_SECURITY,
 164         .get    = f2fs_xattr_generic_get,
 165         .set    = f2fs_xattr_generic_set,
 166 };
 167
 168 static const struct xattr_handler *f2fs_xattr_handler_map[] = {
 169         [F2FS_XATTR_INDEX_USER] = &f2fs_xattr_user_handler,
 170 #ifdef CONFIG_F2FS_FS_POSIX_ACL
 171         [F2FS_XATTR_INDEX_POSIX_ACL_ACCESS] = &posix_acl_access_xattr_handler,
 172         [F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT] = &posix_acl_default_xattr_handler,
 173 #endif
 174         [F2FS_XATTR_INDEX_TRUSTED] = &f2fs_xattr_trusted_handler,
 175 #ifdef CONFIG_F2FS_FS_SECURITY
 176         [F2FS_XATTR_INDEX_SECURITY] = &f2fs_xattr_security_handler,
 177 #endif
 178         [F2FS_XATTR_INDEX_ADVISE] = &f2fs_xattr_advise_handler,
 179 };
 180
 181 const struct xattr_handler *f2fs_xattr_handlers[] = {
 182         &f2fs_xattr_user_handler,
 183 #ifdef CONFIG_F2FS_FS_POSIX_ACL
 184         &posix_acl_access_xattr_handler,
 185         &posix_acl_default_xattr_handler,
 186 #endif
 187         &f2fs_xattr_trusted_handler,
 188 #ifdef CONFIG_F2FS_FS_SECURITY
 189         &f2fs_xattr_security_handler,
 190 #endif
 191         &f2fs_xattr_advise_handler,
 192         NULL,
 193 };
 194
 195 static inline const struct xattr_handler *f2fs_xattr_handler(int index)
 196 {
 197         const struct xattr_handler *handler = NULL;
 198
 199         if (index > 0 && index < ARRAY_SIZE(f2fs_xattr_handler_map))
 200                 handler = f2fs_xattr_handler_map[index];
 201         return handler;
 202 }
 203
 204 static struct f2fs_xattr_entry *__find_xattr(void *base_addr, int index,
 205                                         size_t len, const char *name)
 206 {
 207         struct f2fs_xattr_entry *entry;
 208
 209         list_for_each_xattr(entry, base_addr) {
 210                 if (entry->e_name_index != index)
 211                         continue;
 212                 if (entry->e_name_len != len)
 213                         continue;
 214                 if (!memcmp(entry->e_name, name, len))
 215                         break;
 216         }
 217         return entry;
 218 }
 219
 220 static void *read_all_xattrs(struct inode *inode, struct page *ipage)
 221 {
 222         struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 223         struct f2fs_xattr_header *header;
 224         size_t size = PAGE_SIZE, inline_size = 0;
 225         void *txattr_addr;
 226
 227         inline_size = inline_xattr_size(inode);
 228
 229         txattr_addr = kzalloc(inline_size + size, GFP_F2FS_ZERO);
 230         if (!txattr_addr)
 231                 return NULL;
 232
 233         /* read from inline xattr */
 234         if (inline_size) {
 235                 struct page *page = NULL;
 236                 void *inline_addr;
 237
 238                 if (ipage) {
 239                         inline_addr = inline_xattr_addr(ipage);
 240                 } else {
 241                         page = get_node_page(sbi, inode->i_ino);
 242                         if (IS_ERR(page))
 243                                 goto fail;
 244                         inline_addr = inline_xattr_addr(page);
 245                 }
 246                 memcpy(txattr_addr, inline_addr, inline_size);
 247                 f2fs_put_page(page, 1);
 248         }
 249
 250         /* read from xattr node block */
 251         if (F2FS_I(inode)->i_xattr_nid) {
 252                 struct page *xpage;
 253                 void *xattr_addr;
 254
 255                 /* The inode already has an extended attribute block. */
 256                 xpage = get_node_page(sbi, F2FS_I(inode)->i_xattr_nid);
 257                 if (IS_ERR(xpage))
 258                         goto fail;
 259
 260                 xattr_addr = page_address(xpage);
 261                 memcpy(txattr_addr + inline_size, xattr_addr, PAGE_SIZE);
 262                 f2fs_put_page(xpage, 1);
 263         }
 264
 265         header = XATTR_HDR(txattr_addr);
 266
 267         /* never been allocated xattrs */
 268         if (le32_to_cpu(header->h_magic) != F2FS_XATTR_MAGIC) {
 269                 header->h_magic = cpu_to_le32(F2FS_XATTR_MAGIC);
 270                 header->h_refcount = cpu_to_le32(1);
 271         }
 272         return txattr_addr;
 273 fail:
 274         kzfree(txattr_addr);
 275         return NULL;
 276 }
 277
 278 static inline int write_all_xattrs(struct inode *inode, __u32 hsize,
 279                                 void *txattr_addr, struct page *ipage)
 280 {
 281         struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 282         size_t inline_size = 0;
 283         void *xattr_addr;
 284         struct page *xpage;
 285         nid_t new_nid = 0;
 286         int err;
 287
 288         inline_size = inline_xattr_size(inode);
 289
 290         if (hsize > inline_size && !F2FS_I(inode)->i_xattr_nid)
 291                 if (!alloc_nid(sbi, &new_nid))
 292                         return -ENOSPC;
 293
 294         /* write to inline xattr */
 295         if (inline_size) {
 296                 struct page *page = NULL;
 297                 void *inline_addr;
 298
 299                 if (ipage) {
 300                         inline_addr = inline_xattr_addr(ipage);
 301                         f2fs_wait_on_page_writeback(ipage, NODE, true);
 302                         set_page_dirty(ipage);
 303                 } else {
 304                         page = get_node_page(sbi, inode->i_ino);
 305                         if (IS_ERR(page)) {
 306                                 alloc_nid_failed(sbi, new_nid);
 307                                 return PTR_ERR(page);
 308                         }
 309                         inline_addr = inline_xattr_addr(page);
 310                         f2fs_wait_on_page_writeback(page, NODE, true);
 311                 }
 312                 memcpy(inline_addr, txattr_addr, inline_size);
 313                 f2fs_put_page(page, 1);
 314
 315                 /* no need to use xattr node block */
 316                 if (hsize <= inline_size) {
 317                         err = truncate_xattr_node(inode, ipage);
 318                         alloc_nid_failed(sbi, new_nid);
 319                         return err;
 320                 }
 321         }
 322
 323         /* write to xattr node block */
 324         if (F2FS_I(inode)->i_xattr_nid) {
 325                 xpage = get_node_page(sbi, F2FS_I(inode)->i_xattr_nid);
 326                 if (IS_ERR(xpage)) {
 327                         alloc_nid_failed(sbi, new_nid);
 328                         return PTR_ERR(xpage);
 329                 }
 330                 f2fs_bug_on(sbi, new_nid);
 331                 f2fs_wait_on_page_writeback(xpage, NODE, true);
 332         } else {
 333                 struct dnode_of_data dn;
 334                 set_new_dnode(&dn, inode, NULL, NULL, new_nid);
 335                 xpage = new_node_page(&dn, XATTR_NODE_OFFSET, ipage);
 336                 if (IS_ERR(xpage)) {
 337                         alloc_nid_failed(sbi, new_nid);
 338                         return PTR_ERR(xpage);
 339                 }
 340                 alloc_nid_done(sbi, new_nid);
 341         }
 342
 343         xattr_addr = page_address(xpage);
 344         memcpy(xattr_addr, txattr_addr + inline_size, PAGE_SIZE -
 345                                                 sizeof(struct node_footer));
 346         set_page_dirty(xpage);
 347         f2fs_put_page(xpage, 1);
 348
 349         /* need to checkpoint during fsync */
 350         F2FS_I(inode)->xattr_ver = cur_cp_version(F2FS_CKPT(sbi));
 351         return 0;
 352 }
 353
 354 int f2fs_getxattr(struct inode *inode, int index, const char *name,
 355                 void *buffer, size_t buffer_size, struct page *ipage)
 356 {
 357         struct f2fs_xattr_entry *entry;
 358         void *base_addr;
 359         int error = 0;
 360         size_t size, len;
 361
 362         if (name == NULL)
 363                 return -EINVAL;
 364
 365         len = strlen(name);
 366         if (len > F2FS_NAME_LEN)
 367                 return -ERANGE;
 368
 369         base_addr = read_all_xattrs(inode, ipage);
 370         if (!base_addr)
 371                 return -ENOMEM;
 372
 373         entry = __find_xattr(base_addr, index, len, name);
 374         if (IS_XATTR_LAST_ENTRY(entry)) {
 375                 error = -ENODATA;
 376                 goto cleanup;
 377         }
 378
 379         size = le16_to_cpu(entry->e_value_size);
 380
 381         if (buffer && size > buffer_size) {
 382                 error = -ERANGE;
 383                 goto cleanup;
 384         }
 385
 386         if (buffer) {
 387                 char *pval = entry->e_name + entry->e_name_len;
 388                 memcpy(buffer, pval, size);
 389         }
 390         error = size;
 391
 392 cleanup:
 393         kzfree(base_addr);
 394         return error;
 395 }
 396
 397 ssize_t f2fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
 398 {
 399         struct inode *inode = d_inode(dentry);
 400         struct f2fs_xattr_entry *entry;
 401         void *base_addr;
 402         int error = 0;
 403         size_t rest = buffer_size;
 404
 405         base_addr = read_all_xattrs(inode, NULL);
 406         if (!base_addr)
 407                 return -ENOMEM;
 408
 409         list_for_each_xattr(entry, base_addr) {
 410                 const struct xattr_handler *handler =
 411                         f2fs_xattr_handler(entry->e_name_index);
 412                 const char *prefix;
 413                 size_t prefix_len;
 414                 size_t size;
 415
 416                 if (!handler || (handler->list && !handler->list(dentry)))
 417                         continue;
 418
 419                 prefix = handler->prefix ?: handler->name;
 420                 prefix_len = strlen(prefix);
 421                 size = prefix_len + entry->e_name_len + 1;
 422                 if (buffer) {
 423                         if (size > rest) {
 424                                 error = -ERANGE;
 425                                 goto cleanup;
 426                         }
 427                         memcpy(buffer, prefix, prefix_len);
 428                         buffer += prefix_len;
 429                         memcpy(buffer, entry->e_name, entry->e_name_len);
 430                         buffer += entry->e_name_len;
 431                         *buffer++ = 0;
 432                 }
 433                 rest -= size;
 434         }
 435         error = buffer_size - rest;
 436 cleanup:
 437         kzfree(base_addr);
 438         return error;
 439 }
 440
 441 static int __f2fs_setxattr(struct inode *inode, int index,
 442                         const char *name, const void *value, size_t size,
 443                         struct page *ipage, int flags)
 444 {
 445         struct f2fs_xattr_entry *here, *last;
 446         void *base_addr;
 447         int found, newsize;
 448         size_t len;
 449         __u32 new_hsize;
 450         int error = 0;
 451
 452         if (name == NULL)
 453                 return -EINVAL;
 454
 455         if (value == NULL)
 456                 size = 0;
 457
 458         len = strlen(name);
 459
 460         if (len > F2FS_NAME_LEN)
 461                 return -ERANGE;
 462
 463         if (size > MAX_VALUE_LEN(inode))
 464                 return -E2BIG;
 465
 466         base_addr = read_all_xattrs(inode, ipage);
 467         if (!base_addr)
 468                 return -ENOMEM;
 469
 470         /* find entry with wanted name. */
 471         here = __find_xattr(base_addr, index, len, name);
 472
 473         found = IS_XATTR_LAST_ENTRY(here) ? 0 : 1;
 474
 475         if ((flags & XATTR_REPLACE) && !found) {
 476                 error = -ENODATA;
 477                 goto exit;
 478         } else if ((flags & XATTR_CREATE) && found) {
 479                 error = -EEXIST;
 480                 goto exit;
 481         }
 482
 483         last = here;
 484         while (!IS_XATTR_LAST_ENTRY(last))
 485                 last = XATTR_NEXT_ENTRY(last);
 486
 487         newsize = XATTR_ALIGN(sizeof(struct f2fs_xattr_entry) + len + size);
 488
 489         /* 1. Check space */
 490         if (value) {
 491                 int free;
 492                 /*
 493                  * If value is NULL, it is remove operation.
 494                  * In case of update operation, we calculate free.
 495                  */
 496                 free = MIN_OFFSET(inode) - ((char *)last - (char *)base_addr);
 497                 if (found)
 498                         free = free + ENTRY_SIZE(here);
 499
 500                 if (unlikely(free < newsize)) {
 501                         error = -E2BIG;
 502                         goto exit;
 503                 }
 504         }
 505
 506         /* 2. Remove old entry */
 507         if (found) {
 508                 /*
 509                  * If entry is found, remove old entry.
 510                  * If not found, remove operation is not needed.
 511                  */
 512                 struct f2fs_xattr_entry *next = XATTR_NEXT_ENTRY(here);
 513                 int oldsize = ENTRY_SIZE(here);
 514
 515                 memmove(here, next, (char *)last - (char *)next);
 516                 last = (struct f2fs_xattr_entry *)((char *)last - oldsize);
 517                 memset(last, 0, oldsize);
 518         }
 519
 520         new_hsize = (char *)last - (char *)base_addr;
 521
 522         /* 3. Write new entry */
 523         if (value) {
 524                 char *pval;
 525                 /*
 526                  * Before we come here, old entry is removed.
 527                  * We just write new entry.
 528                  */
 529                 last->e_name_index = index;
 530                 last->e_name_len = len;
 531                 memcpy(last->e_name, name, len);
 532                 pval = last->e_name + len;
 533                 memcpy(pval, value, size);
 534                 last->e_value_size = cpu_to_le16(size);
 535                 new_hsize += newsize;
 536         }
 537
 538         error = write_all_xattrs(inode, new_hsize, base_addr, ipage);
 539         if (error)
 540                 goto exit;
 541
 542         if (is_inode_flag_set(inode, FI_ACL_MODE)) {
 543                 inode->i_mode = F2FS_I(inode)->i_acl_mode;
 544                 inode->i_ctime = CURRENT_TIME;
 545                 clear_inode_flag(inode, FI_ACL_MODE);
 546         }
 547         if (index == F2FS_XATTR_INDEX_ENCRYPTION &&
 548                         !strcmp(name, F2FS_XATTR_NAME_ENCRYPTION_CONTEXT))
 549                 f2fs_set_encrypted_inode(inode);
 550         f2fs_mark_inode_dirty_sync(inode);
 551 exit:
 552         kzfree(base_addr);
 553         return error;
 554 }
 555
 556 int f2fs_setxattr(struct inode *inode, int index, const char *name,
 557                                 const void *value, size_t size,
 558                                 struct page *ipage, int flags)
 559 {
 560         struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 561         int err;
 562
 563         /* this case is only from init_inode_metadata */
 564         if (ipage)
 565                 return __f2fs_setxattr(inode, index, name, value,
 566                                                 size, ipage, flags);
 567         f2fs_balance_fs(sbi, true);
 568
 569         f2fs_lock_op(sbi);
 570         /* protect xattr_ver */
 571         down_write(&F2FS_I(inode)->i_sem);
 572         err = __f2fs_setxattr(inode, index, name, value, size, ipage, flags);
 573         up_write(&F2FS_I(inode)->i_sem);
 574         f2fs_unlock_op(sbi);
 575
 576         f2fs_update_time(sbi, REQ_TIME);
 577         return err;
 578 }