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