media: stv06xx: add missing descriptor sanity checks
[linux/fpc-iii.git] / fs / ext4 / dir.c
blob4dc2615ab289ce56ea6400004bd9c033f13a14b9
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * linux/fs/ext4/dir.c
5 * Copyright (C) 1992, 1993, 1994, 1995
6 * Remy Card (card@masi.ibp.fr)
7 * Laboratoire MASI - Institut Blaise Pascal
8 * Universite Pierre et Marie Curie (Paris VI)
10 * from
12 * linux/fs/minix/dir.c
14 * Copyright (C) 1991, 1992 Linus Torvalds
16 * ext4 directory handling functions
18 * Big-endian to little-endian byte-swapping/bitmaps by
19 * David S. Miller (davem@caip.rutgers.edu), 1995
21 * Hash Tree Directory indexing (c) 2001 Daniel Phillips
25 #include <linux/fs.h>
26 #include <linux/buffer_head.h>
27 #include <linux/slab.h>
28 #include <linux/iversion.h>
29 #include <linux/unicode.h>
30 #include "ext4.h"
31 #include "xattr.h"
33 static int ext4_dx_readdir(struct file *, struct dir_context *);
35 /**
36 * is_dx_dir() - check if a directory is using htree indexing
37 * @inode: directory inode
39 * Check if the given dir-inode refers to an htree-indexed directory
40 * (or a directory which could potentially get converted to use htree
41 * indexing).
43 * Return 1 if it is a dx dir, 0 if not
45 static int is_dx_dir(struct inode *inode)
47 struct super_block *sb = inode->i_sb;
49 if (ext4_has_feature_dir_index(inode->i_sb) &&
50 ((ext4_test_inode_flag(inode, EXT4_INODE_INDEX)) ||
51 ((inode->i_size >> sb->s_blocksize_bits) == 1) ||
52 ext4_has_inline_data(inode)))
53 return 1;
55 return 0;
59 * Return 0 if the directory entry is OK, and 1 if there is a problem
61 * Note: this is the opposite of what ext2 and ext3 historically returned...
63 * bh passed here can be an inode block or a dir data block, depending
64 * on the inode inline data flag.
66 int __ext4_check_dir_entry(const char *function, unsigned int line,
67 struct inode *dir, struct file *filp,
68 struct ext4_dir_entry_2 *de,
69 struct buffer_head *bh, char *buf, int size,
70 unsigned int offset)
72 const char *error_msg = NULL;
73 const int rlen = ext4_rec_len_from_disk(de->rec_len,
74 dir->i_sb->s_blocksize);
75 const int next_offset = ((char *) de - buf) + rlen;
77 if (unlikely(rlen < EXT4_DIR_REC_LEN(1)))
78 error_msg = "rec_len is smaller than minimal";
79 else if (unlikely(rlen % 4 != 0))
80 error_msg = "rec_len % 4 != 0";
81 else if (unlikely(rlen < EXT4_DIR_REC_LEN(de->name_len)))
82 error_msg = "rec_len is too small for name_len";
83 else if (unlikely(next_offset > size))
84 error_msg = "directory entry overrun";
85 else if (unlikely(next_offset > size - EXT4_DIR_REC_LEN(1) &&
86 next_offset != size))
87 error_msg = "directory entry too close to block end";
88 else if (unlikely(le32_to_cpu(de->inode) >
89 le32_to_cpu(EXT4_SB(dir->i_sb)->s_es->s_inodes_count)))
90 error_msg = "inode out of bounds";
91 else
92 return 0;
94 if (filp)
95 ext4_error_file(filp, function, line, bh->b_blocknr,
96 "bad entry in directory: %s - offset=%u, "
97 "inode=%u, rec_len=%d, name_len=%d, size=%d",
98 error_msg, offset, le32_to_cpu(de->inode),
99 rlen, de->name_len, size);
100 else
101 ext4_error_inode(dir, function, line, bh->b_blocknr,
102 "bad entry in directory: %s - offset=%u, "
103 "inode=%u, rec_len=%d, name_len=%d, size=%d",
104 error_msg, offset, le32_to_cpu(de->inode),
105 rlen, de->name_len, size);
107 return 1;
110 static int ext4_readdir(struct file *file, struct dir_context *ctx)
112 unsigned int offset;
113 int i;
114 struct ext4_dir_entry_2 *de;
115 int err;
116 struct inode *inode = file_inode(file);
117 struct super_block *sb = inode->i_sb;
118 struct buffer_head *bh = NULL;
119 struct fscrypt_str fstr = FSTR_INIT(NULL, 0);
121 if (IS_ENCRYPTED(inode)) {
122 err = fscrypt_get_encryption_info(inode);
123 if (err && err != -ENOKEY)
124 return err;
127 if (is_dx_dir(inode)) {
128 err = ext4_dx_readdir(file, ctx);
129 if (err != ERR_BAD_DX_DIR) {
130 return err;
132 /* Can we just clear INDEX flag to ignore htree information? */
133 if (!ext4_has_metadata_csum(sb)) {
135 * We don't set the inode dirty flag since it's not
136 * critical that it gets flushed back to the disk.
138 ext4_clear_inode_flag(inode, EXT4_INODE_INDEX);
142 if (ext4_has_inline_data(inode)) {
143 int has_inline_data = 1;
144 err = ext4_read_inline_dir(file, ctx,
145 &has_inline_data);
146 if (has_inline_data)
147 return err;
150 if (IS_ENCRYPTED(inode)) {
151 err = fscrypt_fname_alloc_buffer(inode, EXT4_NAME_LEN, &fstr);
152 if (err < 0)
153 return err;
156 while (ctx->pos < inode->i_size) {
157 struct ext4_map_blocks map;
159 if (fatal_signal_pending(current)) {
160 err = -ERESTARTSYS;
161 goto errout;
163 cond_resched();
164 offset = ctx->pos & (sb->s_blocksize - 1);
165 map.m_lblk = ctx->pos >> EXT4_BLOCK_SIZE_BITS(sb);
166 map.m_len = 1;
167 err = ext4_map_blocks(NULL, inode, &map, 0);
168 if (err == 0) {
169 /* m_len should never be zero but let's avoid
170 * an infinite loop if it somehow is */
171 if (map.m_len == 0)
172 map.m_len = 1;
173 ctx->pos += map.m_len * sb->s_blocksize;
174 continue;
176 if (err > 0) {
177 pgoff_t index = map.m_pblk >>
178 (PAGE_SHIFT - inode->i_blkbits);
179 if (!ra_has_index(&file->f_ra, index))
180 page_cache_sync_readahead(
181 sb->s_bdev->bd_inode->i_mapping,
182 &file->f_ra, file,
183 index, 1);
184 file->f_ra.prev_pos = (loff_t)index << PAGE_SHIFT;
185 bh = ext4_bread(NULL, inode, map.m_lblk, 0);
186 if (IS_ERR(bh)) {
187 err = PTR_ERR(bh);
188 bh = NULL;
189 goto errout;
193 if (!bh) {
194 /* corrupt size? Maybe no more blocks to read */
195 if (ctx->pos > inode->i_blocks << 9)
196 break;
197 ctx->pos += sb->s_blocksize - offset;
198 continue;
201 /* Check the checksum */
202 if (!buffer_verified(bh) &&
203 !ext4_dirblock_csum_verify(inode, bh)) {
204 EXT4_ERROR_FILE(file, 0, "directory fails checksum "
205 "at offset %llu",
206 (unsigned long long)ctx->pos);
207 ctx->pos += sb->s_blocksize - offset;
208 brelse(bh);
209 bh = NULL;
210 continue;
212 set_buffer_verified(bh);
214 /* If the dir block has changed since the last call to
215 * readdir(2), then we might be pointing to an invalid
216 * dirent right now. Scan from the start of the block
217 * to make sure. */
218 if (!inode_eq_iversion(inode, file->f_version)) {
219 for (i = 0; i < sb->s_blocksize && i < offset; ) {
220 de = (struct ext4_dir_entry_2 *)
221 (bh->b_data + i);
222 /* It's too expensive to do a full
223 * dirent test each time round this
224 * loop, but we do have to test at
225 * least that it is non-zero. A
226 * failure will be detected in the
227 * dirent test below. */
228 if (ext4_rec_len_from_disk(de->rec_len,
229 sb->s_blocksize) < EXT4_DIR_REC_LEN(1))
230 break;
231 i += ext4_rec_len_from_disk(de->rec_len,
232 sb->s_blocksize);
234 offset = i;
235 ctx->pos = (ctx->pos & ~(sb->s_blocksize - 1))
236 | offset;
237 file->f_version = inode_query_iversion(inode);
240 while (ctx->pos < inode->i_size
241 && offset < sb->s_blocksize) {
242 de = (struct ext4_dir_entry_2 *) (bh->b_data + offset);
243 if (ext4_check_dir_entry(inode, file, de, bh,
244 bh->b_data, bh->b_size,
245 offset)) {
247 * On error, skip to the next block
249 ctx->pos = (ctx->pos |
250 (sb->s_blocksize - 1)) + 1;
251 break;
253 offset += ext4_rec_len_from_disk(de->rec_len,
254 sb->s_blocksize);
255 if (le32_to_cpu(de->inode)) {
256 if (!IS_ENCRYPTED(inode)) {
257 if (!dir_emit(ctx, de->name,
258 de->name_len,
259 le32_to_cpu(de->inode),
260 get_dtype(sb, de->file_type)))
261 goto done;
262 } else {
263 int save_len = fstr.len;
264 struct fscrypt_str de_name =
265 FSTR_INIT(de->name,
266 de->name_len);
268 /* Directory is encrypted */
269 err = fscrypt_fname_disk_to_usr(inode,
270 0, 0, &de_name, &fstr);
271 de_name = fstr;
272 fstr.len = save_len;
273 if (err)
274 goto errout;
275 if (!dir_emit(ctx,
276 de_name.name, de_name.len,
277 le32_to_cpu(de->inode),
278 get_dtype(sb, de->file_type)))
279 goto done;
282 ctx->pos += ext4_rec_len_from_disk(de->rec_len,
283 sb->s_blocksize);
285 if ((ctx->pos < inode->i_size) && !dir_relax_shared(inode))
286 goto done;
287 brelse(bh);
288 bh = NULL;
289 offset = 0;
291 done:
292 err = 0;
293 errout:
294 fscrypt_fname_free_buffer(&fstr);
295 brelse(bh);
296 return err;
299 static inline int is_32bit_api(void)
301 #ifdef CONFIG_COMPAT
302 return in_compat_syscall();
303 #else
304 return (BITS_PER_LONG == 32);
305 #endif
309 * These functions convert from the major/minor hash to an f_pos
310 * value for dx directories
312 * Upper layer (for example NFS) should specify FMODE_32BITHASH or
313 * FMODE_64BITHASH explicitly. On the other hand, we allow ext4 to be mounted
314 * directly on both 32-bit and 64-bit nodes, under such case, neither
315 * FMODE_32BITHASH nor FMODE_64BITHASH is specified.
317 static inline loff_t hash2pos(struct file *filp, __u32 major, __u32 minor)
319 if ((filp->f_mode & FMODE_32BITHASH) ||
320 (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
321 return major >> 1;
322 else
323 return ((__u64)(major >> 1) << 32) | (__u64)minor;
326 static inline __u32 pos2maj_hash(struct file *filp, loff_t pos)
328 if ((filp->f_mode & FMODE_32BITHASH) ||
329 (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
330 return (pos << 1) & 0xffffffff;
331 else
332 return ((pos >> 32) << 1) & 0xffffffff;
335 static inline __u32 pos2min_hash(struct file *filp, loff_t pos)
337 if ((filp->f_mode & FMODE_32BITHASH) ||
338 (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
339 return 0;
340 else
341 return pos & 0xffffffff;
345 * Return 32- or 64-bit end-of-file for dx directories
347 static inline loff_t ext4_get_htree_eof(struct file *filp)
349 if ((filp->f_mode & FMODE_32BITHASH) ||
350 (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
351 return EXT4_HTREE_EOF_32BIT;
352 else
353 return EXT4_HTREE_EOF_64BIT;
358 * ext4_dir_llseek() calls generic_file_llseek_size to handle htree
359 * directories, where the "offset" is in terms of the filename hash
360 * value instead of the byte offset.
362 * Because we may return a 64-bit hash that is well beyond offset limits,
363 * we need to pass the max hash as the maximum allowable offset in
364 * the htree directory case.
366 * For non-htree, ext4_llseek already chooses the proper max offset.
368 static loff_t ext4_dir_llseek(struct file *file, loff_t offset, int whence)
370 struct inode *inode = file->f_mapping->host;
371 int dx_dir = is_dx_dir(inode);
372 loff_t ret, htree_max = ext4_get_htree_eof(file);
374 if (likely(dx_dir))
375 ret = generic_file_llseek_size(file, offset, whence,
376 htree_max, htree_max);
377 else
378 ret = ext4_llseek(file, offset, whence);
379 file->f_version = inode_peek_iversion(inode) - 1;
380 return ret;
384 * This structure holds the nodes of the red-black tree used to store
385 * the directory entry in hash order.
387 struct fname {
388 __u32 hash;
389 __u32 minor_hash;
390 struct rb_node rb_hash;
391 struct fname *next;
392 __u32 inode;
393 __u8 name_len;
394 __u8 file_type;
395 char name[0];
399 * This functoin implements a non-recursive way of freeing all of the
400 * nodes in the red-black tree.
402 static void free_rb_tree_fname(struct rb_root *root)
404 struct fname *fname, *next;
406 rbtree_postorder_for_each_entry_safe(fname, next, root, rb_hash)
407 while (fname) {
408 struct fname *old = fname;
409 fname = fname->next;
410 kfree(old);
413 *root = RB_ROOT;
417 static struct dir_private_info *ext4_htree_create_dir_info(struct file *filp,
418 loff_t pos)
420 struct dir_private_info *p;
422 p = kzalloc(sizeof(*p), GFP_KERNEL);
423 if (!p)
424 return NULL;
425 p->curr_hash = pos2maj_hash(filp, pos);
426 p->curr_minor_hash = pos2min_hash(filp, pos);
427 return p;
430 void ext4_htree_free_dir_info(struct dir_private_info *p)
432 free_rb_tree_fname(&p->root);
433 kfree(p);
437 * Given a directory entry, enter it into the fname rb tree.
439 * When filename encryption is enabled, the dirent will hold the
440 * encrypted filename, while the htree will hold decrypted filename.
441 * The decrypted filename is passed in via ent_name. parameter.
443 int ext4_htree_store_dirent(struct file *dir_file, __u32 hash,
444 __u32 minor_hash,
445 struct ext4_dir_entry_2 *dirent,
446 struct fscrypt_str *ent_name)
448 struct rb_node **p, *parent = NULL;
449 struct fname *fname, *new_fn;
450 struct dir_private_info *info;
451 int len;
453 info = dir_file->private_data;
454 p = &info->root.rb_node;
456 /* Create and allocate the fname structure */
457 len = sizeof(struct fname) + ent_name->len + 1;
458 new_fn = kzalloc(len, GFP_KERNEL);
459 if (!new_fn)
460 return -ENOMEM;
461 new_fn->hash = hash;
462 new_fn->minor_hash = minor_hash;
463 new_fn->inode = le32_to_cpu(dirent->inode);
464 new_fn->name_len = ent_name->len;
465 new_fn->file_type = dirent->file_type;
466 memcpy(new_fn->name, ent_name->name, ent_name->len);
467 new_fn->name[ent_name->len] = 0;
469 while (*p) {
470 parent = *p;
471 fname = rb_entry(parent, struct fname, rb_hash);
474 * If the hash and minor hash match up, then we put
475 * them on a linked list. This rarely happens...
477 if ((new_fn->hash == fname->hash) &&
478 (new_fn->minor_hash == fname->minor_hash)) {
479 new_fn->next = fname->next;
480 fname->next = new_fn;
481 return 0;
484 if (new_fn->hash < fname->hash)
485 p = &(*p)->rb_left;
486 else if (new_fn->hash > fname->hash)
487 p = &(*p)->rb_right;
488 else if (new_fn->minor_hash < fname->minor_hash)
489 p = &(*p)->rb_left;
490 else /* if (new_fn->minor_hash > fname->minor_hash) */
491 p = &(*p)->rb_right;
494 rb_link_node(&new_fn->rb_hash, parent, p);
495 rb_insert_color(&new_fn->rb_hash, &info->root);
496 return 0;
502 * This is a helper function for ext4_dx_readdir. It calls filldir
503 * for all entres on the fname linked list. (Normally there is only
504 * one entry on the linked list, unless there are 62 bit hash collisions.)
506 static int call_filldir(struct file *file, struct dir_context *ctx,
507 struct fname *fname)
509 struct dir_private_info *info = file->private_data;
510 struct inode *inode = file_inode(file);
511 struct super_block *sb = inode->i_sb;
513 if (!fname) {
514 ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: comm %s: "
515 "called with null fname?!?", __func__, __LINE__,
516 inode->i_ino, current->comm);
517 return 0;
519 ctx->pos = hash2pos(file, fname->hash, fname->minor_hash);
520 while (fname) {
521 if (!dir_emit(ctx, fname->name,
522 fname->name_len,
523 fname->inode,
524 get_dtype(sb, fname->file_type))) {
525 info->extra_fname = fname;
526 return 1;
528 fname = fname->next;
530 return 0;
533 static int ext4_dx_readdir(struct file *file, struct dir_context *ctx)
535 struct dir_private_info *info = file->private_data;
536 struct inode *inode = file_inode(file);
537 struct fname *fname;
538 int ret;
540 if (!info) {
541 info = ext4_htree_create_dir_info(file, ctx->pos);
542 if (!info)
543 return -ENOMEM;
544 file->private_data = info;
547 if (ctx->pos == ext4_get_htree_eof(file))
548 return 0; /* EOF */
550 /* Some one has messed with f_pos; reset the world */
551 if (info->last_pos != ctx->pos) {
552 free_rb_tree_fname(&info->root);
553 info->curr_node = NULL;
554 info->extra_fname = NULL;
555 info->curr_hash = pos2maj_hash(file, ctx->pos);
556 info->curr_minor_hash = pos2min_hash(file, ctx->pos);
560 * If there are any leftover names on the hash collision
561 * chain, return them first.
563 if (info->extra_fname) {
564 if (call_filldir(file, ctx, info->extra_fname))
565 goto finished;
566 info->extra_fname = NULL;
567 goto next_node;
568 } else if (!info->curr_node)
569 info->curr_node = rb_first(&info->root);
571 while (1) {
573 * Fill the rbtree if we have no more entries,
574 * or the inode has changed since we last read in the
575 * cached entries.
577 if ((!info->curr_node) ||
578 !inode_eq_iversion(inode, file->f_version)) {
579 info->curr_node = NULL;
580 free_rb_tree_fname(&info->root);
581 file->f_version = inode_query_iversion(inode);
582 ret = ext4_htree_fill_tree(file, info->curr_hash,
583 info->curr_minor_hash,
584 &info->next_hash);
585 if (ret < 0)
586 return ret;
587 if (ret == 0) {
588 ctx->pos = ext4_get_htree_eof(file);
589 break;
591 info->curr_node = rb_first(&info->root);
594 fname = rb_entry(info->curr_node, struct fname, rb_hash);
595 info->curr_hash = fname->hash;
596 info->curr_minor_hash = fname->minor_hash;
597 if (call_filldir(file, ctx, fname))
598 break;
599 next_node:
600 info->curr_node = rb_next(info->curr_node);
601 if (info->curr_node) {
602 fname = rb_entry(info->curr_node, struct fname,
603 rb_hash);
604 info->curr_hash = fname->hash;
605 info->curr_minor_hash = fname->minor_hash;
606 } else {
607 if (info->next_hash == ~0) {
608 ctx->pos = ext4_get_htree_eof(file);
609 break;
611 info->curr_hash = info->next_hash;
612 info->curr_minor_hash = 0;
615 finished:
616 info->last_pos = ctx->pos;
617 return 0;
620 static int ext4_dir_open(struct inode * inode, struct file * filp)
622 if (IS_ENCRYPTED(inode))
623 return fscrypt_get_encryption_info(inode) ? -EACCES : 0;
624 return 0;
627 static int ext4_release_dir(struct inode *inode, struct file *filp)
629 if (filp->private_data)
630 ext4_htree_free_dir_info(filp->private_data);
632 return 0;
635 int ext4_check_all_de(struct inode *dir, struct buffer_head *bh, void *buf,
636 int buf_size)
638 struct ext4_dir_entry_2 *de;
639 int rlen;
640 unsigned int offset = 0;
641 char *top;
643 de = (struct ext4_dir_entry_2 *)buf;
644 top = buf + buf_size;
645 while ((char *) de < top) {
646 if (ext4_check_dir_entry(dir, NULL, de, bh,
647 buf, buf_size, offset))
648 return -EFSCORRUPTED;
649 rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
650 de = (struct ext4_dir_entry_2 *)((char *)de + rlen);
651 offset += rlen;
653 if ((char *) de > top)
654 return -EFSCORRUPTED;
656 return 0;
659 const struct file_operations ext4_dir_operations = {
660 .llseek = ext4_dir_llseek,
661 .read = generic_read_dir,
662 .iterate_shared = ext4_readdir,
663 .unlocked_ioctl = ext4_ioctl,
664 #ifdef CONFIG_COMPAT
665 .compat_ioctl = ext4_compat_ioctl,
666 #endif
667 .fsync = ext4_sync_file,
668 .open = ext4_dir_open,
669 .release = ext4_release_dir,
672 #ifdef CONFIG_UNICODE
673 static int ext4_d_compare(const struct dentry *dentry, unsigned int len,
674 const char *str, const struct qstr *name)
676 struct qstr qstr = {.name = str, .len = len };
677 const struct dentry *parent = READ_ONCE(dentry->d_parent);
678 const struct inode *inode = READ_ONCE(parent->d_inode);
680 if (!inode || !IS_CASEFOLDED(inode) ||
681 !EXT4_SB(inode->i_sb)->s_encoding) {
682 if (len != name->len)
683 return -1;
684 return memcmp(str, name->name, len);
687 return ext4_ci_compare(inode, name, &qstr, false);
690 static int ext4_d_hash(const struct dentry *dentry, struct qstr *str)
692 const struct ext4_sb_info *sbi = EXT4_SB(dentry->d_sb);
693 const struct unicode_map *um = sbi->s_encoding;
694 const struct inode *inode = READ_ONCE(dentry->d_inode);
695 unsigned char *norm;
696 int len, ret = 0;
698 if (!inode || !IS_CASEFOLDED(inode) || !um)
699 return 0;
701 norm = kmalloc(PATH_MAX, GFP_ATOMIC);
702 if (!norm)
703 return -ENOMEM;
705 len = utf8_casefold(um, str, norm, PATH_MAX);
706 if (len < 0) {
707 if (ext4_has_strict_mode(sbi))
708 ret = -EINVAL;
709 goto out;
711 str->hash = full_name_hash(dentry, norm, len);
712 out:
713 kfree(norm);
714 return ret;
717 const struct dentry_operations ext4_dentry_ops = {
718 .d_hash = ext4_d_hash,
719 .d_compare = ext4_d_compare,
721 #endif