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         const char *prefix;
  34         int total_len, prefix_len;
  35
  36         switch (handler->flags) {
  37         case F2FS_XATTR_INDEX_USER:
  38                 if (!test_opt(sbi, XATTR_USER))
  39                         return -EOPNOTSUPP;
  40                 break;
  41         case F2FS_XATTR_INDEX_TRUSTED:
  42                 if (!capable(CAP_SYS_ADMIN))
  43                         return -EPERM;
  44                 break;
  45         case F2FS_XATTR_INDEX_SECURITY:
  46                 break;
  47         default:
  48                 return -EINVAL;
  49         }
  50
  51         prefix = xattr_prefix(handler);
  52         prefix_len = strlen(prefix);
  53         total_len = prefix_len + len + 1;
  54         if (list && total_len <= list_size) {
  55                 memcpy(list, prefix, prefix_len);
  56                 memcpy(list + prefix_len, name, len);
  57                 list[prefix_len + len] = '\0';
  58         }
  59         return total_len;
  60 }
  61
  62 static int f2fs_xattr_generic_get(const struct xattr_handler *handler,
  63                 struct dentry *dentry, const char *name, void *buffer,
  64                 size_t size)
  65 {
  66         struct f2fs_sb_info *sbi = F2FS_SB(dentry->d_sb);
  67
  68         switch (handler->flags) {
  69         case F2FS_XATTR_INDEX_USER:
  70                 if (!test_opt(sbi, XATTR_USER))
  71                         return -EOPNOTSUPP;
  72                 break;
  73         case F2FS_XATTR_INDEX_TRUSTED:
  74                 if (!capable(CAP_SYS_ADMIN))
  75                         return -EPERM;
  76                 break;
  77         case F2FS_XATTR_INDEX_SECURITY:
  78                 break;
  79         default:
  80                 return -EINVAL;
  81         }
  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         return f2fs_setxattr(d_inode(dentry), handler->flags, name,
 107                                         value, size, NULL, flags);
 108 }
 109
 110 static size_t f2fs_xattr_advise_list(const struct xattr_handler *handler,
 111                 struct dentry *dentry, char *list, size_t list_size,
 112                 const char *name, size_t len)
 113 {
 114         const char *xname = F2FS_SYSTEM_ADVISE_NAME;
 115         size_t size;
 116
 117         size = strlen(xname) + 1;
 118         if (list && size <= list_size)
 119                 memcpy(list, xname, size);
 120         return size;
 121 }
 122
 123 static int f2fs_xattr_advise_get(const struct xattr_handler *handler,
 124                 struct dentry *dentry, const char *name, void *buffer,
 125                 size_t size)
 126 {
 127         struct inode *inode = d_inode(dentry);
 128
 129         if (buffer)
 130                 *((char *)buffer) = F2FS_I(inode)->i_advise;
 131         return sizeof(char);
 132 }
 133
 134 static int f2fs_xattr_advise_set(const struct xattr_handler *handler,
 135                 struct dentry *dentry, const char *name, const void *value,
 136                 size_t size, int flags)
 137 {
 138         struct inode *inode = d_inode(dentry);
 139
 140         if (!inode_owner_or_capable(inode))
 141                 return -EPERM;
 142         if (value == NULL)
 143                 return -EINVAL;
 144
 145         F2FS_I(inode)->i_advise |= *(char *)value;
 146         mark_inode_dirty(inode);
 147         return 0;
 148 }
 149
 150 #ifdef CONFIG_F2FS_FS_SECURITY
 151 static int f2fs_initxattrs(struct inode *inode, const struct xattr *xattr_array,
 152                 void *page)
 153 {
 154         const struct xattr *xattr;
 155         int err = 0;
 156
 157         for (xattr = xattr_array; xattr->name != NULL; xattr++) {
 158                 err = f2fs_setxattr(inode, F2FS_XATTR_INDEX_SECURITY,
 159                                 xattr->name, xattr->value,
 160                                 xattr->value_len, (struct page *)page, 0);
 161                 if (err < 0)
 162                         break;
 163         }
 164         return err;
 165 }
 166
 167 int f2fs_init_security(struct inode *inode, struct inode *dir,
 168                                 const struct qstr *qstr, struct page *ipage)
 169 {
 170         return security_inode_init_security(inode, dir, qstr,
 171                                 &f2fs_initxattrs, ipage);
 172 }
 173 #endif
 174
 175 const struct xattr_handler f2fs_xattr_user_handler = {
 176         .prefix = XATTR_USER_PREFIX,
 177         .flags  = F2FS_XATTR_INDEX_USER,
 178         .list   = f2fs_xattr_generic_list,
 179         .get    = f2fs_xattr_generic_get,
 180         .set    = f2fs_xattr_generic_set,
 181 };
 182
 183 const struct xattr_handler f2fs_xattr_trusted_handler = {
 184         .prefix = XATTR_TRUSTED_PREFIX,
 185         .flags  = F2FS_XATTR_INDEX_TRUSTED,
 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_advise_handler = {
 192         .name   = F2FS_SYSTEM_ADVISE_NAME,
 193         .flags  = F2FS_XATTR_INDEX_ADVISE,
 194         .list   = f2fs_xattr_advise_list,
 195         .get    = f2fs_xattr_advise_get,
 196         .set    = f2fs_xattr_advise_set,
 197 };
 198
 199 const struct xattr_handler f2fs_xattr_security_handler = {
 200         .prefix = XATTR_SECURITY_PREFIX,
 201         .flags  = F2FS_XATTR_INDEX_SECURITY,
 202         .list   = f2fs_xattr_generic_list,
 203         .get    = f2fs_xattr_generic_get,
 204         .set    = f2fs_xattr_generic_set,
 205 };
 206
 207 static const struct xattr_handler *f2fs_xattr_handler_map[] = {
 208         [F2FS_XATTR_INDEX_USER] = &f2fs_xattr_user_handler,
 209 #ifdef CONFIG_F2FS_FS_POSIX_ACL
 210         [F2FS_XATTR_INDEX_POSIX_ACL_ACCESS] = &posix_acl_access_xattr_handler,
 211         [F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT] = &posix_acl_default_xattr_handler,
 212 #endif
 213         [F2FS_XATTR_INDEX_TRUSTED] = &f2fs_xattr_trusted_handler,
 214 #ifdef CONFIG_F2FS_FS_SECURITY
 215         [F2FS_XATTR_INDEX_SECURITY] = &f2fs_xattr_security_handler,
 216 #endif
 217         [F2FS_XATTR_INDEX_ADVISE] = &f2fs_xattr_advise_handler,
 218 };
 219
 220 const struct xattr_handler *f2fs_xattr_handlers[] = {
 221         &f2fs_xattr_user_handler,
 222 #ifdef CONFIG_F2FS_FS_POSIX_ACL
 223         &posix_acl_access_xattr_handler,
 224         &posix_acl_default_xattr_handler,
 225 #endif
 226         &f2fs_xattr_trusted_handler,
 227 #ifdef CONFIG_F2FS_FS_SECURITY
 228         &f2fs_xattr_security_handler,
 229 #endif
 230         &f2fs_xattr_advise_handler,
 231         NULL,
 232 };
 233
 234 static inline const struct xattr_handler *f2fs_xattr_handler(int index)
 235 {
 236         const struct xattr_handler *handler = NULL;
 237
 238         if (index > 0 && index < ARRAY_SIZE(f2fs_xattr_handler_map))
 239                 handler = f2fs_xattr_handler_map[index];
 240         return handler;
 241 }
 242
 243 static struct f2fs_xattr_entry *__find_xattr(void *base_addr, int index,
 244                                         size_t len, const char *name)
 245 {
 246         struct f2fs_xattr_entry *entry;
 247
 248         list_for_each_xattr(entry, base_addr) {
 249                 if (entry->e_name_index != index)
 250                         continue;
 251                 if (entry->e_name_len != len)
 252                         continue;
 253                 if (!memcmp(entry->e_name, name, len))
 254                         break;
 255         }
 256         return entry;
 257 }
 258
 259 static void *read_all_xattrs(struct inode *inode, struct page *ipage)
 260 {
 261         struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 262         struct f2fs_xattr_header *header;
 263         size_t size = PAGE_SIZE, inline_size = 0;
 264         void *txattr_addr;
 265
 266         inline_size = inline_xattr_size(inode);
 267
 268         txattr_addr = kzalloc(inline_size + size, GFP_F2FS_ZERO);
 269         if (!txattr_addr)
 270                 return NULL;
 271
 272         /* read from inline xattr */
 273         if (inline_size) {
 274                 struct page *page = NULL;
 275                 void *inline_addr;
 276
 277                 if (ipage) {
 278                         inline_addr = inline_xattr_addr(ipage);
 279                 } else {
 280                         page = get_node_page(sbi, inode->i_ino);
 281                         if (IS_ERR(page))
 282                                 goto fail;
 283                         inline_addr = inline_xattr_addr(page);
 284                 }
 285                 memcpy(txattr_addr, inline_addr, inline_size);
 286                 f2fs_put_page(page, 1);
 287         }
 288
 289         /* read from xattr node block */
 290         if (F2FS_I(inode)->i_xattr_nid) {
 291                 struct page *xpage;
 292                 void *xattr_addr;
 293
 294                 /* The inode already has an extended attribute block. */
 295                 xpage = get_node_page(sbi, F2FS_I(inode)->i_xattr_nid);
 296                 if (IS_ERR(xpage))
 297                         goto fail;
 298
 299                 xattr_addr = page_address(xpage);
 300                 memcpy(txattr_addr + inline_size, xattr_addr, PAGE_SIZE);
 301                 f2fs_put_page(xpage, 1);
 302         }
 303
 304         header = XATTR_HDR(txattr_addr);
 305
 306         /* never been allocated xattrs */
 307         if (le32_to_cpu(header->h_magic) != F2FS_XATTR_MAGIC) {
 308                 header->h_magic = cpu_to_le32(F2FS_XATTR_MAGIC);
 309                 header->h_refcount = cpu_to_le32(1);
 310         }
 311         return txattr_addr;
 312 fail:
 313         kzfree(txattr_addr);
 314         return NULL;
 315 }
 316
 317 static inline int write_all_xattrs(struct inode *inode, __u32 hsize,
 318                                 void *txattr_addr, struct page *ipage)
 319 {
 320         struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 321         size_t inline_size = 0;
 322         void *xattr_addr;
 323         struct page *xpage;
 324         nid_t new_nid = 0;
 325         int err;
 326
 327         inline_size = inline_xattr_size(inode);
 328
 329         if (hsize > inline_size && !F2FS_I(inode)->i_xattr_nid)
 330                 if (!alloc_nid(sbi, &new_nid))
 331                         return -ENOSPC;
 332
 333         /* write to inline xattr */
 334         if (inline_size) {
 335                 struct page *page = NULL;
 336                 void *inline_addr;
 337
 338                 if (ipage) {
 339                         inline_addr = inline_xattr_addr(ipage);
 340                         f2fs_wait_on_page_writeback(ipage, NODE);
 341                 } else {
 342                         page = get_node_page(sbi, inode->i_ino);
 343                         if (IS_ERR(page)) {
 344                                 alloc_nid_failed(sbi, new_nid);
 345                                 return PTR_ERR(page);
 346                         }
 347                         inline_addr = inline_xattr_addr(page);
 348                         f2fs_wait_on_page_writeback(page, NODE);
 349                 }
 350                 memcpy(inline_addr, txattr_addr, inline_size);
 351                 f2fs_put_page(page, 1);
 352
 353                 /* no need to use xattr node block */
 354                 if (hsize <= inline_size) {
 355                         err = truncate_xattr_node(inode, ipage);
 356                         alloc_nid_failed(sbi, new_nid);
 357                         return err;
 358                 }
 359         }
 360
 361         /* write to xattr node block */
 362         if (F2FS_I(inode)->i_xattr_nid) {
 363                 xpage = get_node_page(sbi, F2FS_I(inode)->i_xattr_nid);
 364                 if (IS_ERR(xpage)) {
 365                         alloc_nid_failed(sbi, new_nid);
 366                         return PTR_ERR(xpage);
 367                 }
 368                 f2fs_bug_on(sbi, new_nid);
 369                 f2fs_wait_on_page_writeback(xpage, NODE);
 370         } else {
 371                 struct dnode_of_data dn;
 372                 set_new_dnode(&dn, inode, NULL, NULL, new_nid);
 373                 xpage = new_node_page(&dn, XATTR_NODE_OFFSET, ipage);
 374                 if (IS_ERR(xpage)) {
 375                         alloc_nid_failed(sbi, new_nid);
 376                         return PTR_ERR(xpage);
 377                 }
 378                 alloc_nid_done(sbi, new_nid);
 379         }
 380
 381         xattr_addr = page_address(xpage);
 382         memcpy(xattr_addr, txattr_addr + inline_size, PAGE_SIZE -
 383                                                 sizeof(struct node_footer));
 384         set_page_dirty(xpage);
 385         f2fs_put_page(xpage, 1);
 386
 387         /* need to checkpoint during fsync */
 388         F2FS_I(inode)->xattr_ver = cur_cp_version(F2FS_CKPT(sbi));
 389         return 0;
 390 }
 391
 392 int f2fs_getxattr(struct inode *inode, int index, const char *name,
 393                 void *buffer, size_t buffer_size, struct page *ipage)
 394 {
 395         struct f2fs_xattr_entry *entry;
 396         void *base_addr;
 397         int error = 0;
 398         size_t size, len;
 399
 400         if (name == NULL)
 401                 return -EINVAL;
 402
 403         len = strlen(name);
 404         if (len > F2FS_NAME_LEN)
 405                 return -ERANGE;
 406
 407         base_addr = read_all_xattrs(inode, ipage);
 408         if (!base_addr)
 409                 return -ENOMEM;
 410
 411         entry = __find_xattr(base_addr, index, len, name);
 412         if (IS_XATTR_LAST_ENTRY(entry)) {
 413                 error = -ENODATA;
 414                 goto cleanup;
 415         }
 416
 417         size = le16_to_cpu(entry->e_value_size);
 418
 419         if (buffer && size > buffer_size) {
 420                 error = -ERANGE;
 421                 goto cleanup;
 422         }
 423
 424         if (buffer) {
 425                 char *pval = entry->e_name + entry->e_name_len;
 426                 memcpy(buffer, pval, size);
 427         }
 428         error = size;
 429
 430 cleanup:
 431         kzfree(base_addr);
 432         return error;
 433 }
 434
 435 ssize_t f2fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
 436 {
 437         struct inode *inode = d_inode(dentry);
 438         struct f2fs_xattr_entry *entry;
 439         void *base_addr;
 440         int error = 0;
 441         size_t rest = buffer_size;
 442
 443         base_addr = read_all_xattrs(inode, NULL);
 444         if (!base_addr)
 445                 return -ENOMEM;
 446
 447         list_for_each_xattr(entry, base_addr) {
 448                 const struct xattr_handler *handler =
 449                         f2fs_xattr_handler(entry->e_name_index);
 450                 size_t size;
 451
 452                 if (!handler)
 453                         continue;
 454
 455                 size = handler->list(handler, dentry, buffer, rest,
 456                                      entry->e_name, entry->e_name_len);
 457                 if (buffer && size > rest) {
 458                         error = -ERANGE;
 459                         goto cleanup;
 460                 }
 461
 462                 if (buffer)
 463                         buffer += size;
 464                 rest -= size;
 465         }
 466         error = buffer_size - rest;
 467 cleanup:
 468         kzfree(base_addr);
 469         return error;
 470 }
 471
 472 static int __f2fs_setxattr(struct inode *inode, int index,
 473                         const char *name, const void *value, size_t size,
 474                         struct page *ipage, int flags)
 475 {
 476         struct f2fs_inode_info *fi = F2FS_I(inode);
 477         struct f2fs_xattr_entry *here, *last;
 478         void *base_addr;
 479         int found, newsize;
 480         size_t len;
 481         __u32 new_hsize;
 482         int error = -ENOMEM;
 483
 484         if (name == NULL)
 485                 return -EINVAL;
 486
 487         if (value == NULL)
 488                 size = 0;
 489
 490         len = strlen(name);
 491
 492         if (len > F2FS_NAME_LEN)
 493                 return -ERANGE;
 494
 495         if (size > MAX_VALUE_LEN(inode))
 496                 return -E2BIG;
 497
 498         base_addr = read_all_xattrs(inode, ipage);
 499         if (!base_addr)
 500                 goto exit;
 501
 502         /* find entry with wanted name. */
 503         here = __find_xattr(base_addr, index, len, name);
 504
 505         found = IS_XATTR_LAST_ENTRY(here) ? 0 : 1;
 506
 507         if ((flags & XATTR_REPLACE) && !found) {
 508                 error = -ENODATA;
 509                 goto exit;
 510         } else if ((flags & XATTR_CREATE) && found) {
 511                 error = -EEXIST;
 512                 goto exit;
 513         }
 514
 515         last = here;
 516         while (!IS_XATTR_LAST_ENTRY(last))
 517                 last = XATTR_NEXT_ENTRY(last);
 518
 519         newsize = XATTR_ALIGN(sizeof(struct f2fs_xattr_entry) + len + size);
 520
 521         /* 1. Check space */
 522         if (value) {
 523                 int free;
 524                 /*
 525                  * If value is NULL, it is remove operation.
 526                  * In case of update operation, we calculate free.
 527                  */
 528                 free = MIN_OFFSET(inode) - ((char *)last - (char *)base_addr);
 529                 if (found)
 530                         free = free + ENTRY_SIZE(here);
 531
 532                 if (unlikely(free < newsize)) {
 533                         error = -ENOSPC;
 534                         goto exit;
 535                 }
 536         }
 537
 538         /* 2. Remove old entry */
 539         if (found) {
 540                 /*
 541                  * If entry is found, remove old entry.
 542                  * If not found, remove operation is not needed.
 543                  */
 544                 struct f2fs_xattr_entry *next = XATTR_NEXT_ENTRY(here);
 545                 int oldsize = ENTRY_SIZE(here);
 546
 547                 memmove(here, next, (char *)last - (char *)next);
 548                 last = (struct f2fs_xattr_entry *)((char *)last - oldsize);
 549                 memset(last, 0, oldsize);
 550         }
 551
 552         new_hsize = (char *)last - (char *)base_addr;
 553
 554         /* 3. Write new entry */
 555         if (value) {
 556                 char *pval;
 557                 /*
 558                  * Before we come here, old entry is removed.
 559                  * We just write new entry.
 560                  */
 561                 memset(last, 0, newsize);
 562                 last->e_name_index = index;
 563                 last->e_name_len = len;
 564                 memcpy(last->e_name, name, len);
 565                 pval = last->e_name + len;
 566                 memcpy(pval, value, size);
 567                 last->e_value_size = cpu_to_le16(size);
 568                 new_hsize += newsize;
 569         }
 570
 571         error = write_all_xattrs(inode, new_hsize, base_addr, ipage);
 572         if (error)
 573                 goto exit;
 574
 575         if (is_inode_flag_set(fi, FI_ACL_MODE)) {
 576                 inode->i_mode = fi->i_acl_mode;
 577                 inode->i_ctime = CURRENT_TIME;
 578                 clear_inode_flag(fi, FI_ACL_MODE);
 579         }
 580         if (index == F2FS_XATTR_INDEX_ENCRYPTION &&
 581                         !strcmp(name, F2FS_XATTR_NAME_ENCRYPTION_CONTEXT))
 582                 f2fs_set_encrypted_inode(inode);
 583
 584         if (ipage)
 585                 update_inode(inode, ipage);
 586         else
 587                 update_inode_page(inode);
 588 exit:
 589         kzfree(base_addr);
 590         return error;
 591 }
 592
 593 int f2fs_setxattr(struct inode *inode, int index, const char *name,
 594                                 const void *value, size_t size,
 595                                 struct page *ipage, int flags)
 596 {
 597         struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 598         int err;
 599
 600         /* this case is only from init_inode_metadata */
 601         if (ipage)
 602                 return __f2fs_setxattr(inode, index, name, value,
 603                                                 size, ipage, flags);
 604         f2fs_balance_fs(sbi);
 605
 606         f2fs_lock_op(sbi);
 607         /* protect xattr_ver */
 608         down_write(&F2FS_I(inode)->i_sem);
 609         err = __f2fs_setxattr(inode, index, name, value, size, ipage, flags);
 610         up_write(&F2FS_I(inode)->i_sem);
 611         f2fs_unlock_op(sbi);
 612
 613         return err;
 614 }