exfat: fix refcount leak in exfat_find

[ Upstream commit 9aee8de ]

Fix refcount leaks in `exfat_find` related to `exfat_get_dentry_set`.

Function `exfat_get_dentry_set` would increase the reference counter of
`es->bh` on success. Therefore, `exfat_put_dentry_set` must be called
after `exfat_get_dentry_set` to ensure refcount consistency. This patch
relocate two checks to avoid possible leaks.

Fixes: 82ebecd ("exfat: fix improper check of dentry.stream.valid_size")
Fixes: 13940ce ("exfat: add a check for invalid data size")
Signed-off-by: Shuhao Fu <sfual@cse.ust.hk>
Reviewed-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Li hongliang <1468888505@139.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: sfu2

fs/exfat/namei.c

@@ -638,16 +638,6 @@ static int exfat_find(struct inode *dir, struct qstr *qname,
 	info->valid_size = le64_to_cpu(ep2->dentry.stream.valid_size);
 	info->size = le64_to_cpu(ep2->dentry.stream.size);
 
-	if (info->valid_size < 0) {
-		exfat_fs_error(sb, "data valid size is invalid(%lld)", info->valid_size);
-		return -EIO;
-	}
-
-	if (unlikely(EXFAT_B_TO_CLU_ROUND_UP(info->size, sbi) > sbi->used_clusters)) {
-		exfat_fs_error(sb, "data size is invalid(%lld)", info->size);
-		return -EIO;
-	}
-
 	info->start_clu = le32_to_cpu(ep2->dentry.stream.start_clu);
 	if (!is_valid_cluster(sbi, info->start_clu) && info->size) {
 		exfat_warn(sb, "start_clu is invalid cluster(0x%x)",
@@ -685,6 +675,16 @@ static int exfat_find(struct inode *dir, struct qstr *qname,
 			     0);
 	exfat_put_dentry_set(&es, false);
 
+	if (info->valid_size < 0) {
+		exfat_fs_error(sb, "data valid size is invalid(%lld)", info->valid_size);
+		return -EIO;
+	}
+
+	if (unlikely(EXFAT_B_TO_CLU_ROUND_UP(info->size, sbi) > sbi->used_clusters)) {
+		exfat_fs_error(sb, "data size is invalid(%lld)", info->size);
+		return -EIO;
+	}
+
 	if (ei->start_clu == EXFAT_FREE_CLUSTER) {
 		exfat_fs_error(sb,
 			       "non-zero size file starts with zero cluster (size : %llu, p_dir : %u, entry : 0x%08x)",