exfat: fix the infinite loop in __exfat_free_cluster()

In __exfat_free_cluster(), the cluster chain is traversed until the
EOF cluster. If the cluster chain includes a loop due to file system
corruption, the EOF cluster cannot be traversed, resulting in an
infinite loop.

To avoid this infinite loop, this commit changes to only traverse and
free the number of clusters indicated by the file size.

Reported-by: syzbot+1de5a37cb85a2d536330@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=1de5a37cb85a2d536330
Tested-by: syzbot+1de5a37cb85a2d536330@syzkaller.appspotmail.com
Fixes: 31023864e6 ("exfat: add fat entry operations")
Suggested-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
This commit is contained in:
Yuezhang Mo 2024-12-16 13:39:42 +08:00 committed by Namjae Jeon
parent 70465acbb0
commit ffee32cf4b

View File

@ -201,6 +201,8 @@ static int __exfat_free_cluster(struct inode *inode, struct exfat_chain *p_chain
if (err || n_clu == EXFAT_EOF_CLUSTER)
sync = true;
else if (num_clusters >= p_chain->size)
break;
else
next_cmap_i =
BITMAP_OFFSET_SECTOR_INDEX(sb, CLUSTER_TO_BITMAP_ENT(n_clu));