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