fs/ntfs3: Fix slab-out-of-bounds read in hdr_delete_de()

Here is a BUG report from syzbot:

BUG: KASAN: slab-out-of-bounds in hdr_delete_de+0xe0/0x150 fs/ntfs3/index.c:806
Read of size 16842960 at addr ffff888079cc0600 by task syz-executor934/3631

Call Trace:
 memmove+0x25/0x60 mm/kasan/shadow.c:54
 hdr_delete_de+0xe0/0x150 fs/ntfs3/index.c:806
 indx_delete_entry+0x74f/0x3670 fs/ntfs3/index.c:2193
 ni_remove_name+0x27a/0x980 fs/ntfs3/frecord.c:2910
 ntfs_unlink_inode+0x3d4/0x720 fs/ntfs3/inode.c:1712
 ntfs_rename+0x41a/0xcb0 fs/ntfs3/namei.c:276

Before using the meta-data in struct INDEX_HDR, we need to
check index header valid or not. Otherwise, the corruptedi
(or malicious) fs image can cause out-of-bounds access which
could make kernel panic.

Fixes: 82cae26 ("fs/ntfs3: Add initialization of super block")
Reported-by: syzbot+9c2811fd56591639ff5f@syzkaller.appspotmail.com
Signed-off-by: Zeng Heng <zengheng4@huawei.com>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>

Author: henryZe

fs/ntfs3/fslog.c

@@ -2575,7 +2575,7 @@ static int read_next_log_rec(struct ntfs_log *log, struct lcb *lcb, u64 *lsn)
 	return find_log_rec(log, *lsn, lcb);
 }
 
-static inline bool check_index_header(const struct INDEX_HDR *hdr, size_t bytes)
+bool check_index_header(const struct INDEX_HDR *hdr, size_t bytes)
 {
 	__le16 mask;
 	u32 min_de, de_off, used, total;

fs/ntfs3/index.c

@@ -848,6 +848,10 @@ static inline struct NTFS_DE *hdr_delete_de(struct INDEX_HDR *hdr,
 	u32 off = PtrOffset(hdr, re);
 	int bytes = used - (off + esize);
 
+	/* check INDEX_HDR valid before using INDEX_HDR */
+	if (!check_index_header(hdr, le32_to_cpu(hdr->total)))
+		return NULL;
+
 	if (off >= used || esize < sizeof(struct NTFS_DE) ||
 	    bytes < sizeof(struct NTFS_DE))
 		return NULL;

fs/ntfs3/ntfs_fs.h

@@ -581,6 +581,7 @@ int ni_rename(struct ntfs_inode *dir_ni, struct ntfs_inode *new_dir_ni,
 bool ni_is_dirty(struct inode *inode);
 
 /* Globals from fslog.c */
+bool check_index_header(const struct INDEX_HDR *hdr, size_t bytes);
 int log_replay(struct ntfs_inode *ni, bool *initialized);
 
 /* Globals from fsntfs.c */