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 mnt_idmap *idmap, 93 struct exfat_sb_info *sbi, struct inode *inode) 94 { 95 mode_t allow_utime = sbi->options.allow_utime; 96 97 if (!vfsuid_eq_kuid(i_uid_into_vfsuid(idmap, inode), 98 current_fsuid())) { 99 if (vfsgid_in_group_p(i_gid_into_vfsgid(idmap, inode))) 100 allow_utime >>= 3; 101 if (allow_utime & MAY_WRITE) 102 return true; 103 } 104 105 /* use a default check */ 106 return false; 107 } 108 109 static int exfat_sanitize_mode(const struct exfat_sb_info *sbi, 110 struct inode *inode, umode_t *mode_ptr) 111 { 112 mode_t i_mode, mask, perm; 113 114 i_mode = inode->i_mode; 115 116 mask = (S_ISREG(i_mode) || S_ISLNK(i_mode)) ? 117 sbi->options.fs_fmask : sbi->options.fs_dmask; 118 perm = *mode_ptr & ~(S_IFMT | mask); 119 120 /* Of the r and x bits, all (subject to umask) must be present.*/ 121 if ((perm & 0555) != (i_mode & 0555)) 122 return -EPERM; 123 124 if (exfat_mode_can_hold_ro(inode)) { 125 /* 126 * Of the w bits, either all (subject to umask) or none must 127 * be present. 128 */ 129 if ((perm & 0222) && ((perm & 0222) != (0222 & ~mask))) 130 return -EPERM; 131 } else { 132 /* 133 * If exfat_mode_can_hold_ro(inode) is false, can't change 134 * w bits. 135 */ 136 if ((perm & 0222) != (0222 & ~mask)) 137 return -EPERM; 138 } 139 140 *mode_ptr &= S_IFMT | perm; 141 142 return 0; 143 } 144 145 /* resize the file length */ 146 int __exfat_truncate(struct inode *inode) 147 { 148 unsigned int num_clusters_new, num_clusters_phys; 149 unsigned int last_clu = EXFAT_FREE_CLUSTER; 150 struct exfat_chain clu; 151 struct super_block *sb = inode->i_sb; 152 struct exfat_sb_info *sbi = EXFAT_SB(sb); 153 struct exfat_inode_info *ei = EXFAT_I(inode); 154 155 /* check if the given file ID is opened */ 156 if (ei->type != TYPE_FILE && ei->type != TYPE_DIR) 157 return -EPERM; 158 159 exfat_set_volume_dirty(sb); 160 161 num_clusters_new = EXFAT_B_TO_CLU_ROUND_UP(i_size_read(inode), sbi); 162 num_clusters_phys = EXFAT_B_TO_CLU_ROUND_UP(ei->i_size_ondisk, sbi); 163 164 exfat_chain_set(&clu, ei->start_clu, num_clusters_phys, ei->flags); 165 166 if (i_size_read(inode) > 0) { 167 /* 168 * Truncate FAT chain num_clusters after the first cluster 169 * num_clusters = min(new, phys); 170 */ 171 unsigned int num_clusters = 172 min(num_clusters_new, num_clusters_phys); 173 174 /* 175 * Follow FAT chain 176 * (defensive coding - works fine even with corrupted FAT table 177 */ 178 if (clu.flags == ALLOC_NO_FAT_CHAIN) { 179 clu.dir += num_clusters; 180 clu.size -= num_clusters; 181 } else { 182 while (num_clusters > 0) { 183 last_clu = clu.dir; 184 if (exfat_get_next_cluster(sb, &(clu.dir))) 185 return -EIO; 186 187 num_clusters--; 188 clu.size--; 189 } 190 } 191 } else { 192 ei->flags = ALLOC_NO_FAT_CHAIN; 193 ei->start_clu = EXFAT_EOF_CLUSTER; 194 } 195 196 if (i_size_read(inode) < ei->valid_size) 197 ei->valid_size = i_size_read(inode); 198 199 if (ei->type == TYPE_FILE) 200 ei->attr |= EXFAT_ATTR_ARCHIVE; 201 202 /* 203 * update the directory entry 204 * 205 * If the directory entry is updated by mark_inode_dirty(), the 206 * directory entry will be written after a writeback cycle of 207 * updating the bitmap/FAT, which may result in clusters being 208 * freed but referenced by the directory entry in the event of a 209 * sudden power failure. 210 * __exfat_write_inode() is called for directory entry, bitmap 211 * and FAT to be written in a same writeback. 212 */ 213 if (__exfat_write_inode(inode, inode_needs_sync(inode))) 214 return -EIO; 215 216 /* cut off from the FAT chain */ 217 if (ei->flags == ALLOC_FAT_CHAIN && last_clu != EXFAT_FREE_CLUSTER && 218 last_clu != EXFAT_EOF_CLUSTER) { 219 if (exfat_ent_set(sb, last_clu, EXFAT_EOF_CLUSTER)) 220 return -EIO; 221 } 222 223 /* invalidate cache and free the clusters */ 224 /* clear exfat cache */ 225 exfat_cache_inval_inode(inode); 226 227 /* hint information */ 228 ei->hint_bmap.off = EXFAT_EOF_CLUSTER; 229 ei->hint_bmap.clu = EXFAT_EOF_CLUSTER; 230 231 /* hint_stat will be used if this is directory. */ 232 ei->hint_stat.eidx = 0; 233 ei->hint_stat.clu = ei->start_clu; 234 ei->hint_femp.eidx = EXFAT_HINT_NONE; 235 236 /* free the clusters */ 237 if (exfat_free_cluster(inode, &clu)) 238 return -EIO; 239 240 return 0; 241 } 242 243 void exfat_truncate(struct inode *inode) 244 { 245 struct super_block *sb = inode->i_sb; 246 struct exfat_sb_info *sbi = EXFAT_SB(sb); 247 struct exfat_inode_info *ei = EXFAT_I(inode); 248 unsigned int blocksize = i_blocksize(inode); 249 loff_t aligned_size; 250 int err; 251 252 mutex_lock(&sbi->s_lock); 253 if (ei->start_clu == 0) { 254 /* 255 * Empty start_clu != ~0 (not allocated) 256 */ 257 exfat_fs_error(sb, "tried to truncate zeroed cluster."); 258 goto write_size; 259 } 260 261 err = __exfat_truncate(inode); 262 if (err) 263 goto write_size; 264 265 inode->i_blocks = round_up(i_size_read(inode), sbi->cluster_size) >> 9; 266 write_size: 267 aligned_size = i_size_read(inode); 268 if (aligned_size & (blocksize - 1)) { 269 aligned_size |= (blocksize - 1); 270 aligned_size++; 271 } 272 273 if (ei->i_size_ondisk > i_size_read(inode)) 274 ei->i_size_ondisk = aligned_size; 275 276 if (ei->i_size_aligned > i_size_read(inode)) 277 ei->i_size_aligned = aligned_size; 278 mutex_unlock(&sbi->s_lock); 279 } 280 281 int exfat_getattr(struct mnt_idmap *idmap, const struct path *path, 282 struct kstat *stat, unsigned int request_mask, 283 unsigned int query_flags) 284 { 285 struct inode *inode = d_backing_inode(path->dentry); 286 struct exfat_inode_info *ei = EXFAT_I(inode); 287 288 generic_fillattr(idmap, request_mask, inode, stat); 289 exfat_truncate_atime(&stat->atime); 290 stat->result_mask |= STATX_BTIME; 291 stat->btime.tv_sec = ei->i_crtime.tv_sec; 292 stat->btime.tv_nsec = ei->i_crtime.tv_nsec; 293 stat->blksize = EXFAT_SB(inode->i_sb)->cluster_size; 294 return 0; 295 } 296 297 int exfat_setattr(struct mnt_idmap *idmap, struct dentry *dentry, 298 struct iattr *attr) 299 { 300 struct exfat_sb_info *sbi = EXFAT_SB(dentry->d_sb); 301 struct inode *inode = dentry->d_inode; 302 unsigned int ia_valid; 303 int error; 304 305 if ((attr->ia_valid & ATTR_SIZE) && 306 attr->ia_size > i_size_read(inode)) { 307 error = exfat_cont_expand(inode, attr->ia_size); 308 if (error || attr->ia_valid == ATTR_SIZE) 309 return error; 310 attr->ia_valid &= ~ATTR_SIZE; 311 } 312 313 /* Check for setting the inode time. */ 314 ia_valid = attr->ia_valid; 315 if ((ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET)) && 316 exfat_allow_set_time(idmap, sbi, inode)) { 317 attr->ia_valid &= ~(ATTR_MTIME_SET | ATTR_ATIME_SET | 318 ATTR_TIMES_SET); 319 } 320 321 error = setattr_prepare(idmap, dentry, attr); 322 attr->ia_valid = ia_valid; 323 if (error) 324 goto out; 325 326 if (((attr->ia_valid & ATTR_UID) && 327 (!uid_eq(from_vfsuid(idmap, i_user_ns(inode), attr->ia_vfsuid), 328 sbi->options.fs_uid))) || 329 ((attr->ia_valid & ATTR_GID) && 330 (!gid_eq(from_vfsgid(idmap, i_user_ns(inode), attr->ia_vfsgid), 331 sbi->options.fs_gid))) || 332 ((attr->ia_valid & ATTR_MODE) && 333 (attr->ia_mode & ~(S_IFREG | S_IFLNK | S_IFDIR | 0777)))) { 334 error = -EPERM; 335 goto out; 336 } 337 338 /* 339 * We don't return -EPERM here. Yes, strange, but this is too 340 * old behavior. 341 */ 342 if (attr->ia_valid & ATTR_MODE) { 343 if (exfat_sanitize_mode(sbi, inode, &attr->ia_mode) < 0) 344 attr->ia_valid &= ~ATTR_MODE; 345 } 346 347 if (attr->ia_valid & ATTR_SIZE) 348 inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode)); 349 350 setattr_copy(idmap, inode, attr); 351 exfat_truncate_inode_atime(inode); 352 353 if (attr->ia_valid & ATTR_SIZE) { 354 error = exfat_block_truncate_page(inode, attr->ia_size); 355 if (error) 356 goto out; 357 358 down_write(&EXFAT_I(inode)->truncate_lock); 359 truncate_setsize(inode, attr->ia_size); 360 361 /* 362 * __exfat_write_inode() is called from exfat_truncate(), inode 363 * is already written by it, so mark_inode_dirty() is unneeded. 364 */ 365 exfat_truncate(inode); 366 up_write(&EXFAT_I(inode)->truncate_lock); 367 } else 368 mark_inode_dirty(inode); 369 370 out: 371 return error; 372 } 373 374 /* 375 * modified ioctls from fat/file.c by Welmer Almesberger 376 */ 377 static int exfat_ioctl_get_attributes(struct inode *inode, u32 __user *user_attr) 378 { 379 u32 attr; 380 381 inode_lock_shared(inode); 382 attr = exfat_make_attr(inode); 383 inode_unlock_shared(inode); 384 385 return put_user(attr, user_attr); 386 } 387 388 static int exfat_ioctl_set_attributes(struct file *file, u32 __user *user_attr) 389 { 390 struct inode *inode = file_inode(file); 391 struct exfat_sb_info *sbi = EXFAT_SB(inode->i_sb); 392 int is_dir = S_ISDIR(inode->i_mode); 393 u32 attr, oldattr; 394 struct iattr ia; 395 int err; 396 397 err = get_user(attr, user_attr); 398 if (err) 399 goto out; 400 401 err = mnt_want_write_file(file); 402 if (err) 403 goto out; 404 inode_lock(inode); 405 406 oldattr = exfat_make_attr(inode); 407 408 /* 409 * Mask attributes so we don't set reserved fields. 410 */ 411 attr &= (EXFAT_ATTR_READONLY | EXFAT_ATTR_HIDDEN | EXFAT_ATTR_SYSTEM | 412 EXFAT_ATTR_ARCHIVE); 413 attr |= (is_dir ? EXFAT_ATTR_SUBDIR : 0); 414 415 /* Equivalent to a chmod() */ 416 ia.ia_valid = ATTR_MODE | ATTR_CTIME; 417 ia.ia_ctime = current_time(inode); 418 if (is_dir) 419 ia.ia_mode = exfat_make_mode(sbi, attr, 0777); 420 else 421 ia.ia_mode = exfat_make_mode(sbi, attr, 0666 | (inode->i_mode & 0111)); 422 423 /* The root directory has no attributes */ 424 if (inode->i_ino == EXFAT_ROOT_INO && attr != EXFAT_ATTR_SUBDIR) { 425 err = -EINVAL; 426 goto out_unlock_inode; 427 } 428 429 if (((attr | oldattr) & EXFAT_ATTR_SYSTEM) && 430 !capable(CAP_LINUX_IMMUTABLE)) { 431 err = -EPERM; 432 goto out_unlock_inode; 433 } 434 435 /* 436 * The security check is questionable... We single 437 * out the RO attribute for checking by the security 438 * module, just because it maps to a file mode. 439 */ 440 err = security_inode_setattr(file_mnt_idmap(file), 441 file->f_path.dentry, &ia); 442 if (err) 443 goto out_unlock_inode; 444 445 /* This MUST be done before doing anything irreversible... */ 446 err = exfat_setattr(file_mnt_idmap(file), file->f_path.dentry, &ia); 447 if (err) 448 goto out_unlock_inode; 449 450 fsnotify_change(file->f_path.dentry, ia.ia_valid); 451 452 exfat_save_attr(inode, attr); 453 mark_inode_dirty(inode); 454 out_unlock_inode: 455 inode_unlock(inode); 456 mnt_drop_write_file(file); 457 out: 458 return err; 459 } 460 461 static int exfat_ioctl_fitrim(struct inode *inode, unsigned long arg) 462 { 463 struct fstrim_range range; 464 int ret = 0; 465 466 if (!capable(CAP_SYS_ADMIN)) 467 return -EPERM; 468 469 if (!bdev_max_discard_sectors(inode->i_sb->s_bdev)) 470 return -EOPNOTSUPP; 471 472 if (copy_from_user(&range, (struct fstrim_range __user *)arg, sizeof(range))) 473 return -EFAULT; 474 475 range.minlen = max_t(unsigned int, range.minlen, 476 bdev_discard_granularity(inode->i_sb->s_bdev)); 477 478 ret = exfat_trim_fs(inode, &range); 479 if (ret < 0) 480 return ret; 481 482 if (copy_to_user((struct fstrim_range __user *)arg, &range, sizeof(range))) 483 return -EFAULT; 484 485 return 0; 486 } 487 488 long exfat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) 489 { 490 struct inode *inode = file_inode(filp); 491 u32 __user *user_attr = (u32 __user *)arg; 492 493 switch (cmd) { 494 case FAT_IOCTL_GET_ATTRIBUTES: 495 return exfat_ioctl_get_attributes(inode, user_attr); 496 case FAT_IOCTL_SET_ATTRIBUTES: 497 return exfat_ioctl_set_attributes(filp, user_attr); 498 case FITRIM: 499 return exfat_ioctl_fitrim(inode, arg); 500 default: 501 return -ENOTTY; 502 } 503 } 504 505 #ifdef CONFIG_COMPAT 506 long exfat_compat_ioctl(struct file *filp, unsigned int cmd, 507 unsigned long arg) 508 { 509 return exfat_ioctl(filp, cmd, (unsigned long)compat_ptr(arg)); 510 } 511 #endif 512 513 int exfat_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync) 514 { 515 struct inode *inode = filp->f_mapping->host; 516 int err; 517 518 err = __generic_file_fsync(filp, start, end, datasync); 519 if (err) 520 return err; 521 522 err = sync_blockdev(inode->i_sb->s_bdev); 523 if (err) 524 return err; 525 526 return blkdev_issue_flush(inode->i_sb->s_bdev); 527 } 528 529 static int exfat_file_zeroed_range(struct file *file, loff_t start, loff_t end) 530 { 531 int err; 532 struct inode *inode = file_inode(file); 533 struct address_space *mapping = inode->i_mapping; 534 const struct address_space_operations *ops = mapping->a_ops; 535 536 while (start < end) { 537 u32 zerofrom, len; 538 struct page *page = NULL; 539 540 zerofrom = start & (PAGE_SIZE - 1); 541 len = PAGE_SIZE - zerofrom; 542 if (start + len > end) 543 len = end - start; 544 545 err = ops->write_begin(file, mapping, start, len, &page, NULL); 546 if (err) 547 goto out; 548 549 zero_user_segment(page, zerofrom, zerofrom + len); 550 551 err = ops->write_end(file, mapping, start, len, len, page, NULL); 552 if (err < 0) 553 goto out; 554 start += len; 555 556 balance_dirty_pages_ratelimited(mapping); 557 cond_resched(); 558 } 559 560 out: 561 return err; 562 } 563 564 static ssize_t exfat_file_write_iter(struct kiocb *iocb, struct iov_iter *iter) 565 { 566 ssize_t ret; 567 struct file *file = iocb->ki_filp; 568 struct inode *inode = file_inode(file); 569 struct exfat_inode_info *ei = EXFAT_I(inode); 570 loff_t pos = iocb->ki_pos; 571 loff_t valid_size; 572 573 inode_lock(inode); 574 575 valid_size = ei->valid_size; 576 577 ret = generic_write_checks(iocb, iter); 578 if (ret < 0) 579 goto unlock; 580 581 if (pos > valid_size) { 582 ret = exfat_file_zeroed_range(file, valid_size, pos); 583 if (ret < 0 && ret != -ENOSPC) { 584 exfat_err(inode->i_sb, 585 "write: fail to zero from %llu to %llu(%zd)", 586 valid_size, pos, ret); 587 } 588 if (ret < 0) 589 goto unlock; 590 } 591 592 ret = __generic_file_write_iter(iocb, iter); 593 if (ret < 0) 594 goto unlock; 595 596 inode_unlock(inode); 597 598 if (pos > valid_size) 599 pos = valid_size; 600 601 if (iocb_is_dsync(iocb) && iocb->ki_pos > pos) { 602 ssize_t err = vfs_fsync_range(file, pos, iocb->ki_pos - 1, 603 iocb->ki_flags & IOCB_SYNC); 604 if (err < 0) 605 return err; 606 } 607 608 return ret; 609 610 unlock: 611 inode_unlock(inode); 612 613 return ret; 614 } 615 616 static int exfat_file_mmap(struct file *file, struct vm_area_struct *vma) 617 { 618 int ret; 619 struct inode *inode = file_inode(file); 620 struct exfat_inode_info *ei = EXFAT_I(inode); 621 loff_t start = ((loff_t)vma->vm_pgoff << PAGE_SHIFT); 622 loff_t end = min_t(loff_t, i_size_read(inode), 623 start + vma->vm_end - vma->vm_start); 624 625 if ((vma->vm_flags & VM_WRITE) && ei->valid_size < end) { 626 ret = exfat_file_zeroed_range(file, ei->valid_size, end); 627 if (ret < 0) { 628 exfat_err(inode->i_sb, 629 "mmap: fail to zero from %llu to %llu(%d)", 630 start, end, ret); 631 return ret; 632 } 633 } 634 635 return generic_file_mmap(file, vma); 636 } 637 638 const struct file_operations exfat_file_operations = { 639 .llseek = generic_file_llseek, 640 .read_iter = generic_file_read_iter, 641 .write_iter = exfat_file_write_iter, 642 .unlocked_ioctl = exfat_ioctl, 643 #ifdef CONFIG_COMPAT 644 .compat_ioctl = exfat_compat_ioctl, 645 #endif 646 .mmap = exfat_file_mmap, 647 .fsync = exfat_file_fsync, 648 .splice_read = filemap_splice_read, 649 .splice_write = iter_file_splice_write, 650 }; 651 652 const struct inode_operations exfat_file_inode_operations = { 653 .setattr = exfat_setattr, 654 .getattr = exfat_getattr, 655 }; 656