NFS: Use kmemdup_nul() in nfs_readdir_make_qstr()

mainline inclusion
from mainline-v5.6-rc1
commit 3803d672
category: bugfix
bugzilla: NA
CVE: NA

--------------------------------

The directory strings stored in the readdir cache may be used with
printk(), so it is better to ensure they are nul-terminated.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>
Reviewed-by: NBenjamin Coddington <bcodding@redhat.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: NZhang Xiaoxu <zhangxiaoxu5@huawei.com>
Reviewed-by: NZhang Yi <yi.zhang@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

fs/nfs/dir.c

@@ -198,7 +198,7 @@ static
 int nfs_readdir_make_qstr(struct qstr *string, const char *name, unsigned int len)
 {
 	string->len = len;
-	string->name = kmemdup(name, len, GFP_KERNEL);
+	string->name = kmemdup_nul(name, len, GFP_KERNEL);
 	if (string->name == NULL)
 		return -ENOMEM;
 	/*