[v1,2/2] exfat: fix uninit-value in __exfat_get_dentry_set

Commit Message

[e-mail] Oct. 30, 2024, 7:47 a.m. UTC

There is no check if stream size and start_clu are invalid.
If start_clu is EOF cluster and stream size is 4096, It will
cause uninit value access. because ei->hint_femp.eidx could
be 128(if cluster size is 4K) and wrong hint will allocate
next cluster. and this cluster will be same with the cluster
that is allocated by exfat_extend_valid_size(). The previous
patch will check invalid start_clu, but for clarity, initialize
hint_femp.eidx to zero.

Reported-by: [e-mail]
Tested-by: [e-mail]
Signed-off-by: Namjae Jeon <[e-mail]>
Reviewed-by: Yuezhang Mo <[e-mail]>
---
 fs/exfat/namei.c | 1 +
 1 file changed, 1 insertion(+)

Patch

diff --git a/fs/exfat/namei.c b/fs/exfat/namei.c
index 98f67e632ad1..337197ece599 100644
--- a/fs/exfat/namei.c
+++ b/fs/exfat/namei.c
@@ -345,6 +345,7 @@  static int exfat_find_empty_entry(struct inode *inode,
 		if (ei->start_clu == EXFAT_EOF_CLUSTER) {
 			ei->start_clu = clu.dir;
 			p_dir->dir = clu.dir;
+			hint_femp.eidx = 0;
 		}
 
 		/* append to the FAT chain */