[PATCH] fs: add the tuncate check of exfat and hfsplus

From: MIngyi Cong
Date: Sat Mar 04 2023 - 03:36:14 EST


From: Mingyi Cong <congmingyi@xxxxxxxxx>

EXFAT and HFSPLUS will fill zero data in truncated range.
Fix this by adding *_SUPER_MAGIC check.

Signed-off-by: Mingyi Cong <congmingyi@xxxxxxxxx>
---
fs/ksmbd/smb2pdu.c | 4 +++-
include/uapi/linux/magic.h | 2 ++
2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/fs/ksmbd/smb2pdu.c b/fs/ksmbd/smb2pdu.c
index ac029dfd2..10ab929ad 100644
--- a/fs/ksmbd/smb2pdu.c
+++ b/fs/ksmbd/smb2pdu.c
@@ -5738,7 +5738,9 @@ static int set_end_of_file_info(struct ksmbd_work *work, struct ksmbd_file *fp,
* truncate of some filesystem like FAT32 fill zero data in
* truncated range.
*/
- if (inode->i_sb->s_magic != MSDOS_SUPER_MAGIC) {
+ if (inode->i_sb->s_magic != MSDOS_SUPER_MAGIC ||
+ inode->i_sb->s_magic != EXFAT_SUPER_MAGIC ||
+ inode->i_sb->s_magic != HFSPLUS_SUPER_MAGIC) {
ksmbd_debug(SMB, "filename : %s truncated to newsize %lld\n",
fp->filename, newsize);
rc = ksmbd_vfs_truncate(work, fp, newsize);
diff --git a/include/uapi/linux/magic.h b/include/uapi/linux/magic.h
index 35687dcb1..687b7f584 100644
--- a/include/uapi/linux/magic.h
+++ b/include/uapi/linux/magic.h
@@ -43,6 +43,8 @@
#define MINIX3_SUPER_MAGIC 0x4d5a /* minix v3 fs, 60 char names */

#define MSDOS_SUPER_MAGIC 0x4d44 /* MD */
+#define EXFAT_SUPER_MAGIC 0x2011BAB0UL /* EXFAT */
+#define HFSPLUS_SUPER_MAGIC 0x482b /* HFSPLUS */
#define NCP_SUPER_MAGIC 0x564c /* Guess, what 0x564c is :-) */
#define NFS_SUPER_MAGIC 0x6969
#define OCFS2_SUPER_MAGIC 0x7461636f
--
2.34.1