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 size_t f2fs_xattr_generic_list(const struct xattr_handler *handler,
  29                 struct dentry *dentry, char *list, size_t list_size,
  30                 const char *name, size_t len)
  31 {
  32         struct f2fs_sb_info *sbi = F2FS_SB(dentry->d_sb);
  33         int total_len, prefix_len;
  34
  35         switch (handler->flags) {
  36         case F2FS_XATTR_INDEX_USER:
  37                 if (!test_opt(sbi, XATTR_USER))
  38                         return -EOPNOTSUPP;
  39                 break;
  40         case F2FS_XATTR_INDEX_TRUSTED:
  41                 if (!capable(CAP_SYS_ADMIN))
  42                         return -EPERM;
  43                 break;
  44         case F2FS_XATTR_INDEX_SECURITY:
  45                 break;
  46         default:
  47                 return -EINVAL;
  48         }
  49
  50         prefix_len = strlen(handler->prefix);
  51         total_len = prefix_len + len + 1;
  52         if (list && total_len <= list_size) {
  53                 memcpy(list, handler->prefix, prefix_len);
  54                 memcpy(list + prefix_len, name, len);
  55                 list[prefix_len + len] = '\0';
  56         }
  57         return total_len;
  58 }
  59
  60 static int f2fs_xattr_generic_get(const struct xattr_handler *handler,
  61                 struct dentry *dentry, const char *name, void *buffer,
  62                 size_t size)
  63 {
  64         struct f2fs_sb_info *sbi = F2FS_SB(dentry->d_sb);
  65
  66         switch (handler->flags) {
  67         case F2FS_XATTR_INDEX_USER:
  68                 if (!test_opt(sbi, XATTR_USER))
  69                         return -EOPNOTSUPP;
  70                 break;
  71         case F2FS_XATTR_INDEX_TRUSTED:
  72                 if (!capable(CAP_SYS_ADMIN))
  73                         return -EPERM;
  74                 break;
  75         case F2FS_XATTR_INDEX_SECURITY:
  76                 break;
  77         default:
  78                 return -EINVAL;
  79         }
  80         if (strcmp(name, "") == 0)
  81                 return -EINVAL;
  82         return f2fs_getxattr(d_inode(dentry), handler->flags, name,
  83                              buffer, size, NULL);
  84 }
  85
  86 static int f2fs_xattr_generic_set(const struct xattr_handler *handler,
  87                 struct dentry *dentry, const char *name, const void *value,
  88                 size_t size, int flags)
  89 {
  90         struct f2fs_sb_info *sbi = F2FS_SB(dentry->d_sb);
  91
  92         switch (handler->flags) {
  93         case F2FS_XATTR_INDEX_USER:
  94                 if (!test_opt(sbi, XATTR_USER))
  95                         return -EOPNOTSUPP;
  96                 break;
  97         case F2FS_XATTR_INDEX_TRUSTED:
  98                 if (!capable(CAP_SYS_ADMIN))
  99                         return -EPERM;
 100                 break;
 101         case F2FS_XATTR_INDEX_SECURITY:
 102                 break;
 103         default:
 104                 return -EINVAL;
 105         }
 106         if (strcmp(name, "") == 0)
 107                 return -EINVAL;
 108
 109         return f2fs_setxattr(d_inode(dentry), handler->flags, name,
 110                                         value, size, NULL, flags);
 111 }
 112
 113 static size_t f2fs_xattr_advise_list(const struct xattr_handler *handler,
 114                 struct dentry *dentry, char *list, size_t list_size,
 115                 const char *name, size_t len)
 116 {
 117         const char *xname = F2FS_SYSTEM_ADVISE_PREFIX;
 118         size_t size;
 119
 120         size = strlen(xname) + 1;
 121         if (list && size <= list_size)
 122                 memcpy(list, xname, size);
 123         return size;
 124 }
 125
 126 static int f2fs_xattr_advise_get(const struct xattr_handler *handler,
 127                 struct dentry *dentry, const char *name, void *buffer,
 128                 size_t size)
 129 {
 130         struct inode *inode = d_inode(dentry);
 131
 132         if (strcmp(name, "") != 0)
 133                 return -EINVAL;
 134
 135         if (buffer)
 136                 *((char *)buffer) = F2FS_I(inode)->i_advise;
 137         return sizeof(char);
 138 }
 139
 140 static int f2fs_xattr_advise_set(const struct xattr_handler *handler,
 141                 struct dentry *dentry, const char *name, const void *value,
 142                 size_t size, int flags)
 143 {
 144         struct inode *inode = d_inode(dentry);
 145
 146         if (strcmp(name, "") != 0)
 147                 return -EINVAL;
 148         if (!inode_owner_or_capable(inode))
 149                 return -EPERM;
 150         if (value == NULL)
 151                 return -EINVAL;
 152
 153         F2FS_I(inode)->i_advise |= *(char *)value;
 154         mark_inode_dirty(inode);
 155         return 0;
 156 }
 157
 158 #ifdef CONFIG_F2FS_FS_SECURITY
 159 static int f2fs_initxattrs(struct inode *inode, const struct xattr *xattr_array,
 160                 void *page)
 161 {
 162         const struct xattr *xattr;
 163         int err = 0;
 164
 165         for (xattr = xattr_array; xattr->name != NULL; xattr++) {
 166                 err = f2fs_setxattr(inode, F2FS_XATTR_INDEX_SECURITY,
 167                                 xattr->name, xattr->value,
 168                                 xattr->value_len, (struct page *)page, 0);
 169                 if (err < 0)
 170                         break;
 171         }
 172         return err;
 173 }
 174
 175 int f2fs_init_security(struct inode *inode, struct inode *dir,
 176                                 const struct qstr *qstr, struct page *ipage)
 177 {
 178         return security_inode_init_security(inode, dir, qstr,
 179                                 &f2fs_initxattrs, ipage);
 180 }
 181 #endif
 182
 183 const struct xattr_handler f2fs_xattr_user_handler = {
 184         .prefix = XATTR_USER_PREFIX,
 185         .flags  = F2FS_XATTR_INDEX_USER,
 186         .list   = f2fs_xattr_generic_list,
 187         .get    = f2fs_xattr_generic_get,
 188         .set    = f2fs_xattr_generic_set,
 189 };
 190
 191 const struct xattr_handler f2fs_xattr_trusted_handler = {
 192         .prefix = XATTR_TRUSTED_PREFIX,
 193         .flags  = F2FS_XATTR_INDEX_TRUSTED,
 194         .list   = f2fs_xattr_generic_list,
 195         .get    = f2fs_xattr_generic_get,
 196         .set    = f2fs_xattr_generic_set,
 197 };
 198
 199 const struct xattr_handler f2fs_xattr_advise_handler = {
 200         .prefix = F2FS_SYSTEM_ADVISE_PREFIX,
 201         .flags  = F2FS_XATTR_INDEX_ADVISE,
 202         .list   = f2fs_xattr_advise_list,
 203         .get    = f2fs_xattr_advise_get,
 204         .set    = f2fs_xattr_advise_set,
 205 };
 206
 207 const struct xattr_handler f2fs_xattr_security_handler = {
 208         .prefix = XATTR_SECURITY_PREFIX,
 209         .flags  = F2FS_XATTR_INDEX_SECURITY,
 210         .list   = f2fs_xattr_generic_list,
 211         .get    = f2fs_xattr_generic_get,
 212         .set    = f2fs_xattr_generic_set,
 213 };
 214
 215 static const struct xattr_handler *f2fs_xattr_handler_map[] = {
 216         [F2FS_XATTR_INDEX_USER] = &f2fs_xattr_user_handler,
 217 #ifdef CONFIG_F2FS_FS_POSIX_ACL
 218         [F2FS_XATTR_INDEX_POSIX_ACL_ACCESS] = &posix_acl_access_xattr_handler,
 219         [F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT] = &posix_acl_default_xattr_handler,
 220 #endif
 221         [F2FS_XATTR_INDEX_TRUSTED] = &f2fs_xattr_trusted_handler,
 222 #ifdef CONFIG_F2FS_FS_SECURITY
 223         [F2FS_XATTR_INDEX_SECURITY] = &f2fs_xattr_security_handler,
 224 #endif
 225         [F2FS_XATTR_INDEX_ADVISE] = &f2fs_xattr_advise_handler,
 226 };
 227
 228 const struct xattr_handler *f2fs_xattr_handlers[] = {
 229         &f2fs_xattr_user_handler,
 230 #ifdef CONFIG_F2FS_FS_POSIX_ACL
 231         &posix_acl_access_xattr_handler,
 232         &posix_acl_default_xattr_handler,
 233 #endif
 234         &f2fs_xattr_trusted_handler,
 235 #ifdef CONFIG_F2FS_FS_SECURITY
 236         &f2fs_xattr_security_handler,
 237 #endif
 238         &f2fs_xattr_advise_handler,
 239         NULL,
 240 };
 241
 242 static inline const struct xattr_handler *f2fs_xattr_handler(int index)
 243 {
 244         const struct xattr_handler *handler = NULL;
 245
 246         if (index > 0 && index < ARRAY_SIZE(f2fs_xattr_handler_map))
 247                 handler = f2fs_xattr_handler_map[index];
 248         return handler;
 249 }
 250
 251 static struct f2fs_xattr_entry *__find_xattr(void *base_addr, int index,
 252                                         size_t len, const char *name)
 253 {
 254         struct f2fs_xattr_entry *entry;
 255
 256         list_for_each_xattr(entry, base_addr) {
 257                 if (entry->e_name_index != index)
 258                         continue;
 259                 if (entry->e_name_len != len)
 260                         continue;
 261                 if (!memcmp(entry->e_name, name, len))
 262                         break;
 263         }
 264         return entry;
 265 }
 266
 267 static void *read_all_xattrs(struct inode *inode, struct page *ipage)
 268 {
 269         struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 270         struct f2fs_xattr_header *header;
 271         size_t size = PAGE_SIZE, inline_size = 0;
 272         void *txattr_addr;
 273
 274         inline_size = inline_xattr_size(inode);
 275
 276         txattr_addr = kzalloc(inline_size + size, GFP_F2FS_ZERO);
 277         if (!txattr_addr)
 278                 return NULL;
 279
 280         /* read from inline xattr */
 281         if (inline_size) {
 282                 struct page *page = NULL;
 283                 void *inline_addr;
 284
 285                 if (ipage) {
 286                         inline_addr = inline_xattr_addr(ipage);
 287                 } else {
 288                         page = get_node_page(sbi, inode->i_ino);
 289                         if (IS_ERR(page))
 290                                 goto fail;
 291                         inline_addr = inline_xattr_addr(page);
 292                 }
 293                 memcpy(txattr_addr, inline_addr, inline_size);
 294                 f2fs_put_page(page, 1);
 295         }
 296
 297         /* read from xattr node block */
 298         if (F2FS_I(inode)->i_xattr_nid) {
 299                 struct page *xpage;
 300                 void *xattr_addr;
 301
 302                 /* The inode already has an extended attribute block. */
 303                 xpage = get_node_page(sbi, F2FS_I(inode)->i_xattr_nid);
 304                 if (IS_ERR(xpage))
 305                         goto fail;
 306
 307                 xattr_addr = page_address(xpage);
 308                 memcpy(txattr_addr + inline_size, xattr_addr, PAGE_SIZE);
 309                 f2fs_put_page(xpage, 1);
 310         }
 311
 312         header = XATTR_HDR(txattr_addr);
 313
 314         /* never been allocated xattrs */
 315         if (le32_to_cpu(header->h_magic) != F2FS_XATTR_MAGIC) {
 316                 header->h_magic = cpu_to_le32(F2FS_XATTR_MAGIC);
 317                 header->h_refcount = cpu_to_le32(1);
 318         }
 319         return txattr_addr;
 320 fail:
 321         kzfree(txattr_addr);
 322         return NULL;
 323 }
 324
 325 static inline int write_all_xattrs(struct inode *inode, __u32 hsize,
 326                                 void *txattr_addr, struct page *ipage)
 327 {
 328         struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 329         size_t inline_size = 0;
 330         void *xattr_addr;
 331         struct page *xpage;
 332         nid_t new_nid = 0;
 333         int err;
 334
 335         inline_size = inline_xattr_size(inode);
 336
 337         if (hsize > inline_size && !F2FS_I(inode)->i_xattr_nid)
 338                 if (!alloc_nid(sbi, &new_nid))
 339                         return -ENOSPC;
 340
 341         /* write to inline xattr */
 342         if (inline_size) {
 343                 struct page *page = NULL;
 344                 void *inline_addr;
 345
 346                 if (ipage) {
 347                         inline_addr = inline_xattr_addr(ipage);
 348                         f2fs_wait_on_page_writeback(ipage, NODE);
 349                 } else {
 350                         page = get_node_page(sbi, inode->i_ino);
 351                         if (IS_ERR(page)) {
 352                                 alloc_nid_failed(sbi, new_nid);
 353                                 return PTR_ERR(page);
 354                         }
 355                         inline_addr = inline_xattr_addr(page);
 356                         f2fs_wait_on_page_writeback(page, NODE);
 357                 }
 358                 memcpy(inline_addr, txattr_addr, inline_size);
 359                 f2fs_put_page(page, 1);
 360
 361                 /* no need to use xattr node block */
 362                 if (hsize <= inline_size) {
 363                         err = truncate_xattr_node(inode, ipage);
 364                         alloc_nid_failed(sbi, new_nid);
 365                         return err;
 366                 }
 367         }
 368
 369         /* write to xattr node block */
 370         if (F2FS_I(inode)->i_xattr_nid) {
 371                 xpage = get_node_page(sbi, F2FS_I(inode)->i_xattr_nid);
 372                 if (IS_ERR(xpage)) {
 373                         alloc_nid_failed(sbi, new_nid);
 374                         return PTR_ERR(xpage);
 375                 }
 376                 f2fs_bug_on(sbi, new_nid);
 377                 f2fs_wait_on_page_writeback(xpage, NODE);
 378         } else {
 379                 struct dnode_of_data dn;
 380                 set_new_dnode(&dn, inode, NULL, NULL, new_nid);
 381                 xpage = new_node_page(&dn, XATTR_NODE_OFFSET, ipage);
 382                 if (IS_ERR(xpage)) {
 383                         alloc_nid_failed(sbi, new_nid);
 384                         return PTR_ERR(xpage);
 385                 }
 386                 alloc_nid_done(sbi, new_nid);
 387         }
 388
 389         xattr_addr = page_address(xpage);
 390         memcpy(xattr_addr, txattr_addr + inline_size, PAGE_SIZE -
 391                                                 sizeof(struct node_footer));
 392         set_page_dirty(xpage);
 393         f2fs_put_page(xpage, 1);
 394
 395         /* need to checkpoint during fsync */
 396         F2FS_I(inode)->xattr_ver = cur_cp_version(F2FS_CKPT(sbi));
 397         return 0;
 398 }
 399
 400 int f2fs_getxattr(struct inode *inode, int index, const char *name,
 401                 void *buffer, size_t buffer_size, struct page *ipage)
 402 {
 403         struct f2fs_xattr_entry *entry;
 404         void *base_addr;
 405         int error = 0;
 406         size_t size, len;
 407
 408         if (name == NULL)
 409                 return -EINVAL;
 410
 411         len = strlen(name);
 412         if (len > F2FS_NAME_LEN)
 413                 return -ERANGE;
 414
 415         base_addr = read_all_xattrs(inode, ipage);
 416         if (!base_addr)
 417                 return -ENOMEM;
 418
 419         entry = __find_xattr(base_addr, index, len, name);
 420         if (IS_XATTR_LAST_ENTRY(entry)) {
 421                 error = -ENODATA;
 422                 goto cleanup;
 423         }
 424
 425         size = le16_to_cpu(entry->e_value_size);
 426
 427         if (buffer && size > buffer_size) {
 428                 error = -ERANGE;
 429                 goto cleanup;
 430         }
 431
 432         if (buffer) {
 433                 char *pval = entry->e_name + entry->e_name_len;
 434                 memcpy(buffer, pval, size);
 435         }
 436         error = size;
 437
 438 cleanup:
 439         kzfree(base_addr);
 440         return error;
 441 }
 442
 443 ssize_t f2fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
 444 {
 445         struct inode *inode = d_inode(dentry);
 446         struct f2fs_xattr_entry *entry;
 447         void *base_addr;
 448         int error = 0;
 449         size_t rest = buffer_size;
 450
 451         base_addr = read_all_xattrs(inode, NULL);
 452         if (!base_addr)
 453                 return -ENOMEM;
 454
 455         list_for_each_xattr(entry, base_addr) {
 456                 const struct xattr_handler *handler =
 457                         f2fs_xattr_handler(entry->e_name_index);
 458                 size_t size;
 459
 460                 if (!handler)
 461                         continue;
 462
 463                 size = handler->list(handler, dentry, buffer, rest,
 464                                      entry->e_name, entry->e_name_len);
 465                 if (buffer && size > rest) {
 466                         error = -ERANGE;
 467                         goto cleanup;
 468                 }
 469
 470                 if (buffer)
 471                         buffer += size;
 472                 rest -= size;
 473         }
 474         error = buffer_size - rest;
 475 cleanup:
 476         kzfree(base_addr);
 477         return error;
 478 }
 479
 480 static int __f2fs_setxattr(struct inode *inode, int index,
 481                         const char *name, const void *value, size_t size,
 482                         struct page *ipage, int flags)
 483 {
 484         struct f2fs_inode_info *fi = F2FS_I(inode);
 485         struct f2fs_xattr_entry *here, *last;
 486         void *base_addr;
 487         int found, newsize;
 488         size_t len;
 489         __u32 new_hsize;
 490         int error = -ENOMEM;
 491
 492         if (name == NULL)
 493                 return -EINVAL;
 494
 495         if (value == NULL)
 496                 size = 0;
 497
 498         len = strlen(name);
 499
 500         if (len > F2FS_NAME_LEN)
 501                 return -ERANGE;
 502
 503         if (size > MAX_VALUE_LEN(inode))
 504                 return -E2BIG;
 505
 506         base_addr = read_all_xattrs(inode, ipage);
 507         if (!base_addr)
 508                 goto exit;
 509
 510         /* find entry with wanted name. */
 511         here = __find_xattr(base_addr, index, len, name);
 512
 513         found = IS_XATTR_LAST_ENTRY(here) ? 0 : 1;
 514
 515         if ((flags & XATTR_REPLACE) && !found) {
 516                 error = -ENODATA;
 517                 goto exit;
 518         } else if ((flags & XATTR_CREATE) && found) {
 519                 error = -EEXIST;
 520                 goto exit;
 521         }
 522
 523         last = here;
 524         while (!IS_XATTR_LAST_ENTRY(last))
 525                 last = XATTR_NEXT_ENTRY(last);
 526
 527         newsize = XATTR_ALIGN(sizeof(struct f2fs_xattr_entry) + len + size);
 528
 529         /* 1. Check space */
 530         if (value) {
 531                 int free;
 532                 /*
 533                  * If value is NULL, it is remove operation.
 534                  * In case of update operation, we calculate free.
 535                  */
 536                 free = MIN_OFFSET(inode) - ((char *)last - (char *)base_addr);
 537                 if (found)
 538                         free = free + ENTRY_SIZE(here);
 539
 540                 if (unlikely(free < newsize)) {
 541                         error = -ENOSPC;
 542                         goto exit;
 543                 }
 544         }
 545
 546         /* 2. Remove old entry */
 547         if (found) {
 548                 /*
 549                  * If entry is found, remove old entry.
 550                  * If not found, remove operation is not needed.
 551                  */
 552                 struct f2fs_xattr_entry *next = XATTR_NEXT_ENTRY(here);
 553                 int oldsize = ENTRY_SIZE(here);
 554
 555                 memmove(here, next, (char *)last - (char *)next);
 556                 last = (struct f2fs_xattr_entry *)((char *)last - oldsize);
 557                 memset(last, 0, oldsize);
 558         }
 559
 560         new_hsize = (char *)last - (char *)base_addr;
 561
 562         /* 3. Write new entry */
 563         if (value) {
 564                 char *pval;
 565                 /*
 566                  * Before we come here, old entry is removed.
 567                  * We just write new entry.
 568                  */
 569                 memset(last, 0, newsize);
 570                 last->e_name_index = index;
 571                 last->e_name_len = len;
 572                 memcpy(last->e_name, name, len);
 573                 pval = last->e_name + len;
 574                 memcpy(pval, value, size);
 575                 last->e_value_size = cpu_to_le16(size);
 576                 new_hsize += newsize;
 577         }
 578
 579         error = write_all_xattrs(inode, new_hsize, base_addr, ipage);
 580         if (error)
 581                 goto exit;
 582
 583         if (is_inode_flag_set(fi, FI_ACL_MODE)) {
 584                 inode->i_mode = fi->i_acl_mode;
 585                 inode->i_ctime = CURRENT_TIME;
 586                 clear_inode_flag(fi, FI_ACL_MODE);
 587         }
 588         if (index == F2FS_XATTR_INDEX_ENCRYPTION &&
 589                         !strcmp(name, F2FS_XATTR_NAME_ENCRYPTION_CONTEXT))
 590                 f2fs_set_encrypted_inode(inode);
 591
 592         if (ipage)
 593                 update_inode(inode, ipage);
 594         else
 595                 update_inode_page(inode);
 596 exit:
 597         kzfree(base_addr);
 598         return error;
 599 }
 600
 601 int f2fs_setxattr(struct inode *inode, int index, const char *name,
 602                                 const void *value, size_t size,
 603                                 struct page *ipage, int flags)
 604 {
 605         struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 606         int err;
 607
 608         /* this case is only from init_inode_metadata */
 609         if (ipage)
 610                 return __f2fs_setxattr(inode, index, name, value,
 611                                                 size, ipage, flags);
 612         f2fs_balance_fs(sbi);
 613
 614         f2fs_lock_op(sbi);
 615         /* protect xattr_ver */
 616         down_write(&F2FS_I(inode)->i_sem);
 617         err = __f2fs_setxattr(inode, index, name, value, size, ipage, flags);
 618         up_write(&F2FS_I(inode)->i_sem);
 619         f2fs_unlock_op(sbi);
 620
 621         return err;
 622 }