cifs: Use kzfree() to zero out the password

BugLink: https://bugs.launchpad.net/bugs/1845405

[ Upstream commit 478228e5 ]

It's safer to zero out the password so that it can never be disclosed.

Fixes: 0c219f5799c7 ("cifs: set domainName when a domain-key is used in multiuser")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Connor Kuehl <connor.kuehl@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

fs/cifs/connect.c

@@ -2583,7 +2583,7 @@ cifs_set_cifscreds(struct smb_vol *vol, struct cifs_ses *ses)
 			rc = -ENOMEM;
 			kfree(vol->username);
 			vol->username = NULL;
-			kfree(vol->password);
+			kzfree(vol->password);
 			vol->password = NULL;
 			goto out_key_put;
 		}