2022-12-30 00:54:14

by Sungjong Seo

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

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 <[email protected]>
Signed-off-by: Sungjong Seo <[email protected]>
---
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

2023-01-08 01:15:03

by Namjae Jeon

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

2022-12-29 20:52 GMT+09:00, Sungjong Seo <[email protected]>:
> 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 <[email protected]>
> Signed-off-by: Sungjong Seo <[email protected]>
Applied, Thanks!