diff options
| author | Yuezhang Mo <Yuezhang.Mo@sony.com> | 2024-12-16 13:39:42 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-01-17 13:36:10 +0100 |
| commit | 1e92afe80197fd274d582b7972350b054110124c (patch) | |
| tree | 79f1f25c3ba404e5c4bb9835885d0165b540b12e | |
| parent | dc1d7afceb982e8f666e70a582e6b5aa806de063 (diff) | |
| download | linux-1e92afe80197fd274d582b7972350b054110124c.tar.gz linux-1e92afe80197fd274d582b7972350b054110124c.tar.bz2 linux-1e92afe80197fd274d582b7972350b054110124c.zip | |
exfat: fix the infinite loop in __exfat_free_cluster()
[ Upstream commit a5324b3a488d883aa2d42f72260054e87d0940a0 ]
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.
This commit uses the total number of clusters to prevent this infinite
loop.
Reported-by: syzbot+1de5a37cb85a2d536330@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=1de5a37cb85a2d536330
Tested-by: syzbot+1de5a37cb85a2d536330@syzkaller.appspotmail.com
Fixes: 31023864e67a ("exfat: add fat entry operations")
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | fs/exfat/fatent.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/fs/exfat/fatent.c b/fs/exfat/fatent.c index 56b870d9cc0d..428d862a1d2b 100644 --- a/fs/exfat/fatent.c +++ b/fs/exfat/fatent.c @@ -216,6 +216,16 @@ static int __exfat_free_cluster(struct inode *inode, struct exfat_chain *p_chain if (err) goto dec_used_clus; + + if (num_clusters >= sbi->num_clusters - EXFAT_FIRST_CLUSTER) { + /* + * The cluster chain includes a loop, scan the + * bitmap to get the number of used clusters. + */ + exfat_count_used_clusters(sb, &sbi->used_clusters); + + return 0; + } } while (clu != EXFAT_EOF_CLUSTER); } |