[PATCH] exfat: redefine DIR_DELETED as the bad cluster number

From: Sungjong Seo
Date: Thu Dec 29 2022 - 19:30:19 EST


When a file or a directory is deleted, the hint for the cluster of
its parent directory in its in-memory inode is set as DIR_DELETED.
Therefore, DIR_DELETED must be one of invalid cluster numbers. According
to the exFAT specification, a volume can have at most 2^32-11 clusters.
However, DIR_DELETED is wrongly defined as 0xFFFF0321, which could be
a valid cluster number. To fix it, let's redefine DIR_DELETED as
0xFFFFFFF7, the bad cluster number.

Fixes: 1acf1a564b60 ("exfat: add in-memory and on-disk structures and headers")

Reported-by: Yuezhang Mo <Yuezhang.Mo@xxxxxxxx>
Signed-off-by: Sungjong Seo <sj1557.seo@xxxxxxxxxxx>
---
fs/exfat/exfat_fs.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/exfat/exfat_fs.h b/fs/exfat/exfat_fs.h
index bc6d21d7c5ad..25a5df0fdfe0 100644
--- a/fs/exfat/exfat_fs.h
+++ b/fs/exfat/exfat_fs.h
@@ -50,7 +50,7 @@ enum {
#define ES_IDX_LAST_FILENAME(name_len) \
(ES_IDX_FIRST_FILENAME + EXFAT_FILENAME_ENTRY_NUM(name_len) - 1)

-#define DIR_DELETED 0xFFFF0321
+#define DIR_DELETED 0xFFFFFFF7

/* type values */
#define TYPE_UNUSED 0x0000
--
2.25.1