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 19static 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, IS_DIRSYNC(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 72out: 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 81 if (IS_DIRSYNC(inode)) 82 return write_inode_now(inode, 1); 83 84 mark_inode_dirty(inode); 85 86 return 0; 87 88free_clu: 89 exfat_free_cluster(inode, &clu); 90 return -EIO; 91} 92 93static bool exfat_allow_set_time(struct exfat_sb_info *sbi, struct inode *inode) 94{ 95 mode_t allow_utime = sbi->options.allow_utime; 96 97 if (!uid_eq(current_fsuid(), inode->i_uid)) { 98 if (in_group_p(inode->i_gid)) 99 allow_utime >>= 3; 100 if (allow_utime & MAY_WRITE) 101 return true; 102 } 103 104 /* use a default check */ 105 return false; 106} 107 108static int exfat_sanitize_mode(const struct exfat_sb_info *sbi, 109 struct inode *inode, umode_t *mode_ptr) 110{ 111 mode_t i_mode, mask, perm; 112 113 i_mode = inode->i_mode; 114 115 mask = (S_ISREG(i_mode) || S_ISLNK(i_mode)) ? 116 sbi->options.fs_fmask : sbi->options.fs_dmask; 117 perm = *mode_ptr & ~(S_IFMT | mask); 118 119 /* Of the r and x bits, all (subject to umask) must be present.*/ 120 if ((perm & 0555) != (i_mode & 0555)) 121 return -EPERM; 122 123 if (exfat_mode_can_hold_ro(inode)) { 124 /* 125 * Of the w bits, either all (subject to umask) or none must 126 * be present. 127 */ 128 if ((perm & 0222) && ((perm & 0222) != (0222 & ~mask))) 129 return -EPERM; 130 } else { 131 /* 132 * If exfat_mode_can_hold_ro(inode) is false, can't change 133 * w bits. 134 */ 135 if ((perm & 0222) != (0222 & ~mask)) 136 return -EPERM; 137 } 138 139 *mode_ptr &= S_IFMT | perm; 140 141 return 0; 142} 143 144/* resize the file length */ 145int __exfat_truncate(struct inode *inode) 146{ 147 unsigned int num_clusters_new, num_clusters_phys; 148 unsigned int last_clu = EXFAT_FREE_CLUSTER; 149 struct exfat_chain clu; 150 struct super_block *sb = inode->i_sb; 151 struct exfat_sb_info *sbi = EXFAT_SB(sb); 152 struct exfat_inode_info *ei = EXFAT_I(inode); 153 154 /* check if the given file ID is opened */ 155 if (ei->type != TYPE_FILE && ei->type != TYPE_DIR) 156 return -EPERM; 157 158 exfat_set_volume_dirty(sb); 159 160 num_clusters_new = EXFAT_B_TO_CLU_ROUND_UP(i_size_read(inode), sbi); 161 num_clusters_phys = EXFAT_B_TO_CLU_ROUND_UP(ei->i_size_ondisk, sbi); 162 163 exfat_chain_set(&clu, ei->start_clu, num_clusters_phys, ei->flags); 164 165 if (i_size_read(inode) > 0) { 166 /* 167 * Truncate FAT chain num_clusters after the first cluster 168 * num_clusters = min(new, phys); 169 */ 170 unsigned int num_clusters = 171 min(num_clusters_new, num_clusters_phys); 172 173 /* 174 * Follow FAT chain 175 * (defensive coding - works fine even with corrupted FAT table 176 */ 177 if (clu.flags == ALLOC_NO_FAT_CHAIN) { 178 clu.dir += num_clusters; 179 clu.size -= num_clusters; 180 } else { 181 while (num_clusters > 0) { 182 last_clu = clu.dir; 183 if (exfat_get_next_cluster(sb, &(clu.dir))) 184 return -EIO; 185 186 num_clusters--; 187 clu.size--; 188 } 189 } 190 } else { 191 ei->flags = ALLOC_NO_FAT_CHAIN; 192 ei->start_clu = EXFAT_EOF_CLUSTER; 193 } 194 195 if (i_size_read(inode) < ei->valid_size) 196 ei->valid_size = i_size_read(inode); 197 198 if (ei->type == TYPE_FILE) 199 ei->attr |= EXFAT_ATTR_ARCHIVE; 200 201 /* 202 * update the directory entry 203 * 204 * If the directory entry is updated by mark_inode_dirty(), the 205 * directory entry will be written after a writeback cycle of 206 * updating the bitmap/FAT, which may result in clusters being 207 * freed but referenced by the directory entry in the event of a 208 * sudden power failure. 209 * __exfat_write_inode() is called for directory entry, bitmap 210 * and FAT to be written in a same writeback. 211 */ 212 if (__exfat_write_inode(inode, inode_needs_sync(inode))) 213 return -EIO; 214 215 /* cut off from the FAT chain */ 216 if (ei->flags == ALLOC_FAT_CHAIN && last_clu != EXFAT_FREE_CLUSTER && 217 last_clu != EXFAT_EOF_CLUSTER) { 218 if (exfat_ent_set(sb, last_clu, EXFAT_EOF_CLUSTER)) 219 return -EIO; 220 } 221 222 /* invalidate cache and free the clusters */ 223 /* clear exfat cache */ 224 exfat_cache_inval_inode(inode); 225 226 /* hint information */ 227 ei->hint_bmap.off = EXFAT_EOF_CLUSTER; 228 ei->hint_bmap.clu = EXFAT_EOF_CLUSTER; 229 230 /* hint_stat will be used if this is directory. */ 231 ei->hint_stat.eidx = 0; 232 ei->hint_stat.clu = ei->start_clu; 233 ei->hint_femp.eidx = EXFAT_HINT_NONE; 234 235 /* free the clusters */ 236 if (exfat_free_cluster(inode, &clu)) 237 return -EIO; 238 239 return 0; 240} 241 242void exfat_truncate(struct inode *inode) 243{ 244 struct super_block *sb = inode->i_sb; 245 struct exfat_sb_info *sbi = EXFAT_SB(sb); 246 struct exfat_inode_info *ei = EXFAT_I(inode); 247 unsigned int blocksize = i_blocksize(inode); 248 loff_t aligned_size; 249 int err; 250 251 mutex_lock(&sbi->s_lock); 252 if (ei->start_clu == 0) { 253 /* 254 * Empty start_clu != ~0 (not allocated) 255 */ 256 exfat_fs_error(sb, "tried to truncate zeroed cluster."); 257 goto write_size; 258 } 259 260 err = __exfat_truncate(inode); 261 if (err) 262 goto write_size; 263 264 inode->i_blocks = round_up(i_size_read(inode), sbi->cluster_size) >> 9; 265write_size: 266 aligned_size = i_size_read(inode); 267 if (aligned_size & (blocksize - 1)) { 268 aligned_size |= (blocksize - 1); 269 aligned_size++; 270 } 271 272 if (ei->i_size_ondisk > i_size_read(inode)) 273 ei->i_size_ondisk = aligned_size; 274 275 if (ei->i_size_aligned > i_size_read(inode)) 276 ei->i_size_aligned = aligned_size; 277 mutex_unlock(&sbi->s_lock); 278} 279 280int exfat_getattr(struct mnt_idmap *idmap, const struct path *path, 281 struct kstat *stat, unsigned int request_mask, 282 unsigned int query_flags) 283{ 284 struct inode *inode = d_backing_inode(path->dentry); 285 struct exfat_inode_info *ei = EXFAT_I(inode); 286 287 generic_fillattr(&nop_mnt_idmap, request_mask, inode, stat); 288 exfat_truncate_atime(&stat->atime); 289 stat->result_mask |= STATX_BTIME; 290 stat->btime.tv_sec = ei->i_crtime.tv_sec; 291 stat->btime.tv_nsec = ei->i_crtime.tv_nsec; 292 stat->blksize = EXFAT_SB(inode->i_sb)->cluster_size; 293 return 0; 294} 295 296int exfat_setattr(struct mnt_idmap *idmap, struct dentry *dentry, 297 struct iattr *attr) 298{ 299 struct exfat_sb_info *sbi = EXFAT_SB(dentry->d_sb); 300 struct inode *inode = dentry->d_inode; 301 unsigned int ia_valid; 302 int error; 303 304 if ((attr->ia_valid & ATTR_SIZE) && 305 attr->ia_size > i_size_read(inode)) { 306 error = exfat_cont_expand(inode, attr->ia_size); 307 if (error || attr->ia_valid == ATTR_SIZE) 308 return error; 309 attr->ia_valid &= ~ATTR_SIZE; 310 } 311 312 /* Check for setting the inode time. */ 313 ia_valid = attr->ia_valid; 314 if ((ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET)) && 315 exfat_allow_set_time(sbi, inode)) { 316 attr->ia_valid &= ~(ATTR_MTIME_SET | ATTR_ATIME_SET | 317 ATTR_TIMES_SET); 318 } 319 320 error = setattr_prepare(&nop_mnt_idmap, dentry, attr); 321 attr->ia_valid = ia_valid; 322 if (error) 323 goto out; 324 325 if (((attr->ia_valid & ATTR_UID) && 326 !uid_eq(attr->ia_uid, sbi->options.fs_uid)) || 327 ((attr->ia_valid & ATTR_GID) && 328 !gid_eq(attr->ia_gid, sbi->options.fs_gid)) || 329 ((attr->ia_valid & ATTR_MODE) && 330 (attr->ia_mode & ~(S_IFREG | S_IFLNK | S_IFDIR | 0777)))) { 331 error = -EPERM; 332 goto out; 333 } 334 335 /* 336 * We don't return -EPERM here. Yes, strange, but this is too 337 * old behavior. 338 */ 339 if (attr->ia_valid & ATTR_MODE) { 340 if (exfat_sanitize_mode(sbi, inode, &attr->ia_mode) < 0) 341 attr->ia_valid &= ~ATTR_MODE; 342 } 343 344 if (attr->ia_valid & ATTR_SIZE) 345 inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode)); 346 347 setattr_copy(&nop_mnt_idmap, inode, attr); 348 exfat_truncate_inode_atime(inode); 349 350 if (attr->ia_valid & ATTR_SIZE) { 351 error = exfat_block_truncate_page(inode, attr->ia_size); 352 if (error) 353 goto out; 354 355 down_write(&EXFAT_I(inode)->truncate_lock); 356 truncate_setsize(inode, attr->ia_size); 357 358 /* 359 * __exfat_write_inode() is called from exfat_truncate(), inode 360 * is already written by it, so mark_inode_dirty() is unneeded. 361 */ 362 exfat_truncate(inode); 363 up_write(&EXFAT_I(inode)->truncate_lock); 364 } else 365 mark_inode_dirty(inode); 366 367out: 368 return error; 369} 370 371/* 372 * modified ioctls from fat/file.c by Welmer Almesberger 373 */ 374static int exfat_ioctl_get_attributes(struct inode *inode, u32 __user *user_attr) 375{ 376 u32 attr; 377 378 inode_lock_shared(inode); 379 attr = exfat_make_attr(inode); 380 inode_unlock_shared(inode); 381 382 return put_user(attr, user_attr); 383} 384 385static int exfat_ioctl_set_attributes(struct file *file, u32 __user *user_attr) 386{ 387 struct inode *inode = file_inode(file); 388 struct exfat_sb_info *sbi = EXFAT_SB(inode->i_sb); 389 int is_dir = S_ISDIR(inode->i_mode); 390 u32 attr, oldattr; 391 struct iattr ia; 392 int err; 393 394 err = get_user(attr, user_attr); 395 if (err) 396 goto out; 397 398 err = mnt_want_write_file(file); 399 if (err) 400 goto out; 401 inode_lock(inode); 402 403 oldattr = exfat_make_attr(inode); 404 405 /* 406 * Mask attributes so we don't set reserved fields. 407 */ 408 attr &= (EXFAT_ATTR_READONLY | EXFAT_ATTR_HIDDEN | EXFAT_ATTR_SYSTEM | 409 EXFAT_ATTR_ARCHIVE); 410 attr |= (is_dir ? EXFAT_ATTR_SUBDIR : 0); 411 412 /* Equivalent to a chmod() */ 413 ia.ia_valid = ATTR_MODE | ATTR_CTIME; 414 ia.ia_ctime = current_time(inode); 415 if (is_dir) 416 ia.ia_mode = exfat_make_mode(sbi, attr, 0777); 417 else 418 ia.ia_mode = exfat_make_mode(sbi, attr, 0666 | (inode->i_mode & 0111)); 419 420 /* The root directory has no attributes */ 421 if (inode->i_ino == EXFAT_ROOT_INO && attr != EXFAT_ATTR_SUBDIR) { 422 err = -EINVAL; 423 goto out_unlock_inode; 424 } 425 426 if (((attr | oldattr) & EXFAT_ATTR_SYSTEM) && 427 !capable(CAP_LINUX_IMMUTABLE)) { 428 err = -EPERM; 429 goto out_unlock_inode; 430 } 431 432 /* 433 * The security check is questionable... We single 434 * out the RO attribute for checking by the security 435 * module, just because it maps to a file mode. 436 */ 437 err = security_inode_setattr(file_mnt_idmap(file), 438 file->f_path.dentry, &ia); 439 if (err) 440 goto out_unlock_inode; 441 442 /* This MUST be done before doing anything irreversible... */ 443 err = exfat_setattr(file_mnt_idmap(file), file->f_path.dentry, &ia); 444 if (err) 445 goto out_unlock_inode; 446 447 fsnotify_change(file->f_path.dentry, ia.ia_valid); 448 449 exfat_save_attr(inode, attr); 450 mark_inode_dirty(inode); 451out_unlock_inode: 452 inode_unlock(inode); 453 mnt_drop_write_file(file); 454out: 455 return err; 456} 457 458static int exfat_ioctl_fitrim(struct inode *inode, unsigned long arg) 459{ 460 struct fstrim_range range; 461 int ret = 0; 462 463 if (!capable(CAP_SYS_ADMIN)) 464 return -EPERM; 465 466 if (!bdev_max_discard_sectors(inode->i_sb->s_bdev)) 467 return -EOPNOTSUPP; 468 469 if (copy_from_user(&range, (struct fstrim_range __user *)arg, sizeof(range))) 470 return -EFAULT; 471 472 range.minlen = max_t(unsigned int, range.minlen, 473 bdev_discard_granularity(inode->i_sb->s_bdev)); 474 475 ret = exfat_trim_fs(inode, &range); 476 if (ret < 0) 477 return ret; 478 479 if (copy_to_user((struct fstrim_range __user *)arg, &range, sizeof(range))) 480 return -EFAULT; 481 482 return 0; 483} 484 485long exfat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) 486{ 487 struct inode *inode = file_inode(filp); 488 u32 __user *user_attr = (u32 __user *)arg; 489 490 switch (cmd) { 491 case FAT_IOCTL_GET_ATTRIBUTES: 492 return exfat_ioctl_get_attributes(inode, user_attr); 493 case FAT_IOCTL_SET_ATTRIBUTES: 494 return exfat_ioctl_set_attributes(filp, user_attr); 495 case FITRIM: 496 return exfat_ioctl_fitrim(inode, arg); 497 default: 498 return -ENOTTY; 499 } 500} 501 502#ifdef CONFIG_COMPAT 503long exfat_compat_ioctl(struct file *filp, unsigned int cmd, 504 unsigned long arg) 505{ 506 return exfat_ioctl(filp, cmd, (unsigned long)compat_ptr(arg)); 507} 508#endif 509 510int exfat_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync) 511{ 512 struct inode *inode = filp->f_mapping->host; 513 int err; 514 515 err = __generic_file_fsync(filp, start, end, datasync); 516 if (err) 517 return err; 518 519 err = sync_blockdev(inode->i_sb->s_bdev); 520 if (err) 521 return err; 522 523 return blkdev_issue_flush(inode->i_sb->s_bdev); 524} 525 526static int exfat_file_zeroed_range(struct file *file, loff_t start, loff_t end) 527{ 528 int err; 529 struct inode *inode = file_inode(file); 530 struct address_space *mapping = inode->i_mapping; 531 const struct address_space_operations *ops = mapping->a_ops; 532 533 while (start < end) { 534 u32 zerofrom, len; 535 struct page *page = NULL; 536 537 zerofrom = start & (PAGE_SIZE - 1); 538 len = PAGE_SIZE - zerofrom; 539 if (start + len > end) 540 len = end - start; 541 542 err = ops->write_begin(file, mapping, start, len, &page, NULL); 543 if (err) 544 goto out; 545 546 zero_user_segment(page, zerofrom, zerofrom + len); 547 548 err = ops->write_end(file, mapping, start, len, len, page, NULL); 549 if (err < 0) 550 goto out; 551 start += len; 552 553 balance_dirty_pages_ratelimited(mapping); 554 cond_resched(); 555 } 556 557out: 558 return err; 559} 560 561static ssize_t exfat_file_write_iter(struct kiocb *iocb, struct iov_iter *iter) 562{ 563 ssize_t ret; 564 struct file *file = iocb->ki_filp; 565 struct inode *inode = file_inode(file); 566 struct exfat_inode_info *ei = EXFAT_I(inode); 567 loff_t pos = iocb->ki_pos; 568 loff_t valid_size; 569 570 inode_lock(inode); 571 572 valid_size = ei->valid_size; 573 574 ret = generic_write_checks(iocb, iter); 575 if (ret < 0) 576 goto unlock; 577 578 if (pos > valid_size) { 579 ret = exfat_file_zeroed_range(file, valid_size, pos); 580 if (ret < 0 && ret != -ENOSPC) { 581 exfat_err(inode->i_sb, 582 "write: fail to zero from %llu to %llu(%zd)", 583 valid_size, pos, ret); 584 } 585 if (ret < 0) 586 goto unlock; 587 } 588 589 ret = __generic_file_write_iter(iocb, iter); 590 if (ret < 0) 591 goto unlock; 592 593 inode_unlock(inode); 594 595 if (pos > valid_size) 596 pos = valid_size; 597 598 if (iocb_is_dsync(iocb) && iocb->ki_pos > pos) { 599 ssize_t err = vfs_fsync_range(file, pos, iocb->ki_pos - 1, 600 iocb->ki_flags & IOCB_SYNC); 601 if (err < 0) 602 return err; 603 } 604 605 return ret; 606 607unlock: 608 inode_unlock(inode); 609 610 return ret; 611} 612 613static int exfat_file_mmap(struct file *file, struct vm_area_struct *vma) 614{ 615 int ret; 616 struct inode *inode = file_inode(file); 617 struct exfat_inode_info *ei = EXFAT_I(inode); 618 loff_t start = ((loff_t)vma->vm_pgoff << PAGE_SHIFT); 619 loff_t end = min_t(loff_t, i_size_read(inode), 620 start + vma->vm_end - vma->vm_start); 621 622 if ((vma->vm_flags & VM_WRITE) && ei->valid_size < end) { 623 ret = exfat_file_zeroed_range(file, ei->valid_size, end); 624 if (ret < 0) { 625 exfat_err(inode->i_sb, 626 "mmap: fail to zero from %llu to %llu(%d)", 627 start, end, ret); 628 return ret; 629 } 630 } 631 632 return generic_file_mmap(file, vma); 633} 634 635const struct file_operations exfat_file_operations = { 636 .llseek = generic_file_llseek, 637 .read_iter = generic_file_read_iter, 638 .write_iter = exfat_file_write_iter, 639 .unlocked_ioctl = exfat_ioctl, 640#ifdef CONFIG_COMPAT 641 .compat_ioctl = exfat_compat_ioctl, 642#endif 643 .mmap = exfat_file_mmap, 644 .fsync = exfat_file_fsync, 645 .splice_read = filemap_splice_read, 646 .splice_write = iter_file_splice_write, 647}; 648 649const struct inode_operations exfat_file_inode_operations = { 650 .setattr = exfat_setattr, 651 .getattr = exfat_getattr, 652}; 653