1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Copyright (C) 2012-2013 Samsung Electronics Co., Ltd. 4 */ 5 6 #include <linux/slab.h> 7 #include <linux/compat.h> 8 #include <linux/cred.h> 9 #include <linux/buffer_head.h> 10 #include <linux/blkdev.h> 11 #include <linux/fsnotify.h> 12 #include <linux/security.h> 13 #include <linux/msdos_fs.h> 14 #include <linux/writeback.h> 15 16 #include "exfat_raw.h" 17 #include "exfat_fs.h" 18 19 static int exfat_cont_expand(struct inode *inode, loff_t size) 20 { 21 int ret; 22 unsigned int num_clusters, new_num_clusters, last_clu; 23 struct exfat_inode_info *ei = EXFAT_I(inode); 24 struct super_block *sb = inode->i_sb; 25 struct exfat_sb_info *sbi = EXFAT_SB(sb); 26 struct exfat_chain clu; 27 28 ret = inode_newsize_ok(inode, size); 29 if (ret) 30 return ret; 31 32 num_clusters = EXFAT_B_TO_CLU_ROUND_UP(ei->i_size_ondisk, sbi); 33 new_num_clusters = EXFAT_B_TO_CLU_ROUND_UP(size, sbi); 34 35 if (new_num_clusters == num_clusters) 36 goto out; 37 38 if (num_clusters) { 39 exfat_chain_set(&clu, ei->start_clu, num_clusters, ei->flags); 40 ret = exfat_find_last_cluster(sb, &clu, &last_clu); 41 if (ret) 42 return ret; 43 44 clu.dir = last_clu + 1; 45 } else { 46 last_clu = EXFAT_EOF_CLUSTER; 47 clu.dir = EXFAT_EOF_CLUSTER; 48 } 49 50 clu.size = 0; 51 clu.flags = ei->flags; 52 53 ret = exfat_alloc_cluster(inode, new_num_clusters - num_clusters, 54 &clu, inode_needs_sync(inode)); 55 if (ret) 56 return ret; 57 58 /* Append new clusters to chain */ 59 if (num_clusters) { 60 if (clu.flags != ei->flags) 61 if (exfat_chain_cont_cluster(sb, ei->start_clu, num_clusters)) 62 goto free_clu; 63 64 if (clu.flags == ALLOC_FAT_CHAIN) 65 if (exfat_ent_set(sb, last_clu, clu.dir)) 66 goto free_clu; 67 } else 68 ei->start_clu = clu.dir; 69 70 ei->flags = clu.flags; 71 72 out: 73 inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode)); 74 /* Expanded range not zeroed, do not update valid_size */ 75 i_size_write(inode, size); 76 77 ei->i_size_aligned = round_up(size, sb->s_blocksize); 78 ei->i_size_ondisk = ei->i_size_aligned; 79 inode->i_blocks = round_up(size, sbi->cluster_size) >> 9; 80 mark_inode_dirty(inode); 81 82 if (IS_SYNC(inode)) 83 return write_inode_now(inode, 1); 84 85 return 0; 86 87 free_clu: 88 exfat_free_cluster(inode, &clu); 89 return -EIO; 90 } 91 92 static bool exfat_allow_set_time(struct exfat_sb_info *sbi, struct inode *inode) 93 { 94 mode_t allow_utime = sbi->options.allow_utime; 95 96 if (!uid_eq(current_fsuid(), inode->i_uid)) { 97 if (in_group_p(inode->i_gid)) 98 allow_utime >>= 3; 99 if (allow_utime & MAY_WRITE) 100 return true; 101 } 102 103 /* use a default check */ 104 return false; 105 } 106 107 static int exfat_sanitize_mode(const struct exfat_sb_info *sbi, 108 struct inode *inode, umode_t *mode_ptr) 109 { 110 mode_t i_mode, mask, perm; 111 112 i_mode = inode->i_mode; 113 114 mask = (S_ISREG(i_mode) || S_ISLNK(i_mode)) ? 115 sbi->options.fs_fmask : sbi->options.fs_dmask; 116 perm = *mode_ptr & ~(S_IFMT | mask); 117 118 /* Of the r and x bits, all (subject to umask) must be present.*/ 119 if ((perm & 0555) != (i_mode & 0555)) 120 return -EPERM; 121 122 if (exfat_mode_can_hold_ro(inode)) { 123 /* 124 * Of the w bits, either all (subject to umask) or none must 125 * be present. 126 */ 127 if ((perm & 0222) && ((perm & 0222) != (0222 & ~mask))) 128 return -EPERM; 129 } else { 130 /* 131 * If exfat_mode_can_hold_ro(inode) is false, can't change 132 * w bits. 133 */ 134 if ((perm & 0222) != (0222 & ~mask)) 135 return -EPERM; 136 } 137 138 *mode_ptr &= S_IFMT | perm; 139 140 return 0; 141 } 142 143 /* resize the file length */ 144 int __exfat_truncate(struct inode *inode) 145 { 146 unsigned int num_clusters_new, num_clusters_phys; 147 unsigned int last_clu = EXFAT_FREE_CLUSTER; 148 struct exfat_chain clu; 149 struct super_block *sb = inode->i_sb; 150 struct exfat_sb_info *sbi = EXFAT_SB(sb); 151 struct exfat_inode_info *ei = EXFAT_I(inode); 152 153 /* check if the given file ID is opened */ 154 if (ei->type != TYPE_FILE && ei->type != TYPE_DIR) 155 return -EPERM; 156 157 exfat_set_volume_dirty(sb); 158 159 num_clusters_new = EXFAT_B_TO_CLU_ROUND_UP(i_size_read(inode), sbi); 160 num_clusters_phys = EXFAT_B_TO_CLU_ROUND_UP(ei->i_size_ondisk, sbi); 161 162 exfat_chain_set(&clu, ei->start_clu, num_clusters_phys, ei->flags); 163 164 if (i_size_read(inode) > 0) { 165 /* 166 * Truncate FAT chain num_clusters after the first cluster 167 * num_clusters = min(new, phys); 168 */ 169 unsigned int num_clusters = 170 min(num_clusters_new, num_clusters_phys); 171 172 /* 173 * Follow FAT chain 174 * (defensive coding - works fine even with corrupted FAT table 175 */ 176 if (clu.flags == ALLOC_NO_FAT_CHAIN) { 177 clu.dir += num_clusters; 178 clu.size -= num_clusters; 179 } else { 180 while (num_clusters > 0) { 181 last_clu = clu.dir; 182 if (exfat_get_next_cluster(sb, &(clu.dir))) 183 return -EIO; 184 185 num_clusters--; 186 clu.size--; 187 } 188 } 189 } else { 190 ei->flags = ALLOC_NO_FAT_CHAIN; 191 ei->start_clu = EXFAT_EOF_CLUSTER; 192 } 193 194 if (i_size_read(inode) < ei->valid_size) 195 ei->valid_size = i_size_read(inode); 196 197 if (ei->type == TYPE_FILE) 198 ei->attr |= EXFAT_ATTR_ARCHIVE; 199 200 /* 201 * update the directory entry 202 * 203 * If the directory entry is updated by mark_inode_dirty(), the 204 * directory entry will be written after a writeback cycle of 205 * updating the bitmap/FAT, which may result in clusters being 206 * freed but referenced by the directory entry in the event of a 207 * sudden power failure. 208 * __exfat_write_inode() is called for directory entry, bitmap 209 * and FAT to be written in a same writeback. 210 */ 211 if (__exfat_write_inode(inode, inode_needs_sync(inode))) 212 return -EIO; 213 214 /* cut off from the FAT chain */ 215 if (ei->flags == ALLOC_FAT_CHAIN && last_clu != EXFAT_FREE_CLUSTER && 216 last_clu != EXFAT_EOF_CLUSTER) { 217 if (exfat_ent_set(sb, last_clu, EXFAT_EOF_CLUSTER)) 218 return -EIO; 219 } 220 221 /* invalidate cache and free the clusters */ 222 /* clear exfat cache */ 223 exfat_cache_inval_inode(inode); 224 225 /* hint information */ 226 ei->hint_bmap.off = EXFAT_EOF_CLUSTER; 227 ei->hint_bmap.clu = EXFAT_EOF_CLUSTER; 228 229 /* hint_stat will be used if this is directory. */ 230 ei->hint_stat.eidx = 0; 231 ei->hint_stat.clu = ei->start_clu; 232 ei->hint_femp.eidx = EXFAT_HINT_NONE; 233 234 /* free the clusters */ 235 if (exfat_free_cluster(inode, &clu)) 236 return -EIO; 237 238 return 0; 239 } 240 241 void exfat_truncate(struct inode *inode) 242 { 243 struct super_block *sb = inode->i_sb; 244 struct exfat_sb_info *sbi = EXFAT_SB(sb); 245 struct exfat_inode_info *ei = EXFAT_I(inode); 246 unsigned int blocksize = i_blocksize(inode); 247 loff_t aligned_size; 248 int err; 249 250 mutex_lock(&sbi->s_lock); 251 if (ei->start_clu == 0) { 252 /* 253 * Empty start_clu != ~0 (not allocated) 254 */ 255 exfat_fs_error(sb, "tried to truncate zeroed cluster."); 256 goto write_size; 257 } 258 259 err = __exfat_truncate(inode); 260 if (err) 261 goto write_size; 262 263 inode->i_blocks = round_up(i_size_read(inode), sbi->cluster_size) >> 9; 264 write_size: 265 aligned_size = i_size_read(inode); 266 if (aligned_size & (blocksize - 1)) { 267 aligned_size |= (blocksize - 1); 268 aligned_size++; 269 } 270 271 if (ei->i_size_ondisk > i_size_read(inode)) 272 ei->i_size_ondisk = aligned_size; 273 274 if (ei->i_size_aligned > i_size_read(inode)) 275 ei->i_size_aligned = aligned_size; 276 mutex_unlock(&sbi->s_lock); 277 } 278 279 int exfat_getattr(struct mnt_idmap *idmap, const struct path *path, 280 struct kstat *stat, unsigned int request_mask, 281 unsigned int query_flags) 282 { 283 struct inode *inode = d_backing_inode(path->dentry); 284 struct exfat_inode_info *ei = EXFAT_I(inode); 285 286 generic_fillattr(&nop_mnt_idmap, request_mask, inode, stat); 287 exfat_truncate_atime(&stat->atime); 288 stat->result_mask |= STATX_BTIME; 289 stat->btime.tv_sec = ei->i_crtime.tv_sec; 290 stat->btime.tv_nsec = ei->i_crtime.tv_nsec; 291 stat->blksize = EXFAT_SB(inode->i_sb)->cluster_size; 292 return 0; 293 } 294 295 int exfat_setattr(struct mnt_idmap *idmap, struct dentry *dentry, 296 struct iattr *attr) 297 { 298 struct exfat_sb_info *sbi = EXFAT_SB(dentry->d_sb); 299 struct inode *inode = dentry->d_inode; 300 unsigned int ia_valid; 301 int error; 302 303 if ((attr->ia_valid & ATTR_SIZE) && 304 attr->ia_size > i_size_read(inode)) { 305 error = exfat_cont_expand(inode, attr->ia_size); 306 if (error || attr->ia_valid == ATTR_SIZE) 307 return error; 308 attr->ia_valid &= ~ATTR_SIZE; 309 } 310 311 /* Check for setting the inode time. */ 312 ia_valid = attr->ia_valid; 313 if ((ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET)) && 314 exfat_allow_set_time(sbi, inode)) { 315 attr->ia_valid &= ~(ATTR_MTIME_SET | ATTR_ATIME_SET | 316 ATTR_TIMES_SET); 317 } 318 319 error = setattr_prepare(&nop_mnt_idmap, dentry, attr); 320 attr->ia_valid = ia_valid; 321 if (error) 322 goto out; 323 324 if (((attr->ia_valid & ATTR_UID) && 325 !uid_eq(attr->ia_uid, sbi->options.fs_uid)) || 326 ((attr->ia_valid & ATTR_GID) && 327 !gid_eq(attr->ia_gid, sbi->options.fs_gid)) || 328 ((attr->ia_valid & ATTR_MODE) && 329 (attr->ia_mode & ~(S_IFREG | S_IFLNK | S_IFDIR | 0777)))) { 330 error = -EPERM; 331 goto out; 332 } 333 334 /* 335 * We don't return -EPERM here. Yes, strange, but this is too 336 * old behavior. 337 */ 338 if (attr->ia_valid & ATTR_MODE) { 339 if (exfat_sanitize_mode(sbi, inode, &attr->ia_mode) < 0) 340 attr->ia_valid &= ~ATTR_MODE; 341 } 342 343 if (attr->ia_valid & ATTR_SIZE) 344 inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode)); 345 346 setattr_copy(&nop_mnt_idmap, inode, attr); 347 exfat_truncate_inode_atime(inode); 348 349 if (attr->ia_valid & ATTR_SIZE) { 350 error = exfat_block_truncate_page(inode, attr->ia_size); 351 if (error) 352 goto out; 353 354 down_write(&EXFAT_I(inode)->truncate_lock); 355 truncate_setsize(inode, attr->ia_size); 356 357 /* 358 * __exfat_write_inode() is called from exfat_truncate(), inode 359 * is already written by it, so mark_inode_dirty() is unneeded. 360 */ 361 exfat_truncate(inode); 362 up_write(&EXFAT_I(inode)->truncate_lock); 363 } else 364 mark_inode_dirty(inode); 365 366 out: 367 return error; 368 } 369 370 /* 371 * modified ioctls from fat/file.c by Welmer Almesberger 372 */ 373 static int exfat_ioctl_get_attributes(struct inode *inode, u32 __user *user_attr) 374 { 375 u32 attr; 376 377 inode_lock_shared(inode); 378 attr = exfat_make_attr(inode); 379 inode_unlock_shared(inode); 380 381 return put_user(attr, user_attr); 382 } 383 384 static int exfat_ioctl_set_attributes(struct file *file, u32 __user *user_attr) 385 { 386 struct inode *inode = file_inode(file); 387 struct exfat_sb_info *sbi = EXFAT_SB(inode->i_sb); 388 int is_dir = S_ISDIR(inode->i_mode); 389 u32 attr, oldattr; 390 struct iattr ia; 391 int err; 392 393 err = get_user(attr, user_attr); 394 if (err) 395 goto out; 396 397 err = mnt_want_write_file(file); 398 if (err) 399 goto out; 400 inode_lock(inode); 401 402 oldattr = exfat_make_attr(inode); 403 404 /* 405 * Mask attributes so we don't set reserved fields. 406 */ 407 attr &= (EXFAT_ATTR_READONLY | EXFAT_ATTR_HIDDEN | EXFAT_ATTR_SYSTEM | 408 EXFAT_ATTR_ARCHIVE); 409 attr |= (is_dir ? EXFAT_ATTR_SUBDIR : 0); 410 411 /* Equivalent to a chmod() */ 412 ia.ia_valid = ATTR_MODE | ATTR_CTIME; 413 ia.ia_ctime = current_time(inode); 414 if (is_dir) 415 ia.ia_mode = exfat_make_mode(sbi, attr, 0777); 416 else 417 ia.ia_mode = exfat_make_mode(sbi, attr, 0666 | (inode->i_mode & 0111)); 418 419 /* The root directory has no attributes */ 420 if (inode->i_ino == EXFAT_ROOT_INO && attr != EXFAT_ATTR_SUBDIR) { 421 err = -EINVAL; 422 goto out_unlock_inode; 423 } 424 425 if (((attr | oldattr) & EXFAT_ATTR_SYSTEM) && 426 !capable(CAP_LINUX_IMMUTABLE)) { 427 err = -EPERM; 428 goto out_unlock_inode; 429 } 430 431 /* 432 * The security check is questionable... We single 433 * out the RO attribute for checking by the security 434 * module, just because it maps to a file mode. 435 */ 436 err = security_inode_setattr(file_mnt_idmap(file), 437 file->f_path.dentry, &ia); 438 if (err) 439 goto out_unlock_inode; 440 441 /* This MUST be done before doing anything irreversible... */ 442 err = exfat_setattr(file_mnt_idmap(file), file->f_path.dentry, &ia); 443 if (err) 444 goto out_unlock_inode; 445 446 fsnotify_change(file->f_path.dentry, ia.ia_valid); 447 448 exfat_save_attr(inode, attr); 449 mark_inode_dirty(inode); 450 out_unlock_inode: 451 inode_unlock(inode); 452 mnt_drop_write_file(file); 453 out: 454 return err; 455 } 456 457 static int exfat_ioctl_fitrim(struct inode *inode, unsigned long arg) 458 { 459 struct fstrim_range range; 460 int ret = 0; 461 462 if (!capable(CAP_SYS_ADMIN)) 463 return -EPERM; 464 465 if (!bdev_max_discard_sectors(inode->i_sb->s_bdev)) 466 return -EOPNOTSUPP; 467 468 if (copy_from_user(&range, (struct fstrim_range __user *)arg, sizeof(range))) 469 return -EFAULT; 470 471 range.minlen = max_t(unsigned int, range.minlen, 472 bdev_discard_granularity(inode->i_sb->s_bdev)); 473 474 ret = exfat_trim_fs(inode, &range); 475 if (ret < 0) 476 return ret; 477 478 if (copy_to_user((struct fstrim_range __user *)arg, &range, sizeof(range))) 479 return -EFAULT; 480 481 return 0; 482 } 483 484 long exfat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) 485 { 486 struct inode *inode = file_inode(filp); 487 u32 __user *user_attr = (u32 __user *)arg; 488 489 switch (cmd) { 490 case FAT_IOCTL_GET_ATTRIBUTES: 491 return exfat_ioctl_get_attributes(inode, user_attr); 492 case FAT_IOCTL_SET_ATTRIBUTES: 493 return exfat_ioctl_set_attributes(filp, user_attr); 494 case FITRIM: 495 return exfat_ioctl_fitrim(inode, arg); 496 default: 497 return -ENOTTY; 498 } 499 } 500 501 #ifdef CONFIG_COMPAT 502 long exfat_compat_ioctl(struct file *filp, unsigned int cmd, 503 unsigned long arg) 504 { 505 return exfat_ioctl(filp, cmd, (unsigned long)compat_ptr(arg)); 506 } 507 #endif 508 509 int exfat_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync) 510 { 511 struct inode *inode = filp->f_mapping->host; 512 int err; 513 514 err = __generic_file_fsync(filp, start, end, datasync); 515 if (err) 516 return err; 517 518 err = sync_blockdev(inode->i_sb->s_bdev); 519 if (err) 520 return err; 521 522 return blkdev_issue_flush(inode->i_sb->s_bdev); 523 } 524 525 static int exfat_file_zeroed_range(struct file *file, loff_t start, loff_t end) 526 { 527 int err; 528 struct inode *inode = file_inode(file); 529 struct address_space *mapping = inode->i_mapping; 530 const struct address_space_operations *ops = mapping->a_ops; 531 532 while (start < end) { 533 u32 zerofrom, len; 534 struct page *page = NULL; 535 536 zerofrom = start & (PAGE_SIZE - 1); 537 len = PAGE_SIZE - zerofrom; 538 if (start + len > end) 539 len = end - start; 540 541 err = ops->write_begin(file, mapping, start, len, &page, NULL); 542 if (err) 543 goto out; 544 545 zero_user_segment(page, zerofrom, zerofrom + len); 546 547 err = ops->write_end(file, mapping, start, len, len, page, NULL); 548 if (err < 0) 549 goto out; 550 start += len; 551 552 balance_dirty_pages_ratelimited(mapping); 553 cond_resched(); 554 } 555 556 out: 557 return err; 558 } 559 560 static ssize_t exfat_file_write_iter(struct kiocb *iocb, struct iov_iter *iter) 561 { 562 ssize_t ret; 563 struct file *file = iocb->ki_filp; 564 struct inode *inode = file_inode(file); 565 struct exfat_inode_info *ei = EXFAT_I(inode); 566 loff_t pos = iocb->ki_pos; 567 loff_t valid_size; 568 569 inode_lock(inode); 570 571 valid_size = ei->valid_size; 572 573 ret = generic_write_checks(iocb, iter); 574 if (ret < 0) 575 goto unlock; 576 577 if (pos > valid_size) { 578 ret = exfat_file_zeroed_range(file, valid_size, pos); 579 if (ret < 0 && ret != -ENOSPC) { 580 exfat_err(inode->i_sb, 581 "write: fail to zero from %llu to %llu(%zd)", 582 valid_size, pos, ret); 583 } 584 if (ret < 0) 585 goto unlock; 586 } 587 588 ret = __generic_file_write_iter(iocb, iter); 589 if (ret < 0) 590 goto unlock; 591 592 inode_unlock(inode); 593 594 if (pos > valid_size) 595 pos = valid_size; 596 597 if (iocb_is_dsync(iocb) && iocb->ki_pos > pos) { 598 ssize_t err = vfs_fsync_range(file, pos, iocb->ki_pos - 1, 599 iocb->ki_flags & IOCB_SYNC); 600 if (err < 0) 601 return err; 602 } 603 604 return ret; 605 606 unlock: 607 inode_unlock(inode); 608 609 return ret; 610 } 611 612 static int exfat_file_mmap(struct file *file, struct vm_area_struct *vma) 613 { 614 int ret; 615 struct inode *inode = file_inode(file); 616 struct exfat_inode_info *ei = EXFAT_I(inode); 617 loff_t start = ((loff_t)vma->vm_pgoff << PAGE_SHIFT); 618 loff_t end = min_t(loff_t, i_size_read(inode), 619 start + vma->vm_end - vma->vm_start); 620 621 if ((vma->vm_flags & VM_WRITE) && ei->valid_size < end) { 622 ret = exfat_file_zeroed_range(file, ei->valid_size, end); 623 if (ret < 0) { 624 exfat_err(inode->i_sb, 625 "mmap: fail to zero from %llu to %llu(%d)", 626 start, end, ret); 627 return ret; 628 } 629 } 630 631 return generic_file_mmap(file, vma); 632 } 633 634 const struct file_operations exfat_file_operations = { 635 .llseek = generic_file_llseek, 636 .read_iter = generic_file_read_iter, 637 .write_iter = exfat_file_write_iter, 638 .unlocked_ioctl = exfat_ioctl, 639 #ifdef CONFIG_COMPAT 640 .compat_ioctl = exfat_compat_ioctl, 641 #endif 642 .mmap = exfat_file_mmap, 643 .fsync = exfat_file_fsync, 644 .splice_read = filemap_splice_read, 645 .splice_write = iter_file_splice_write, 646 }; 647 648 const struct inode_operations exfat_file_inode_operations = { 649 .setattr = exfat_setattr, 650 .getattr = exfat_getattr, 651 }; 652