openvpn-authenticator: Break read loop when daemon goes away

Fixes: #12963
Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>
Tested-by: Adolf Belka <adolf.belka@ipfire.org>

config/ovpn/openvpn-authenticator

@@ -68,6 +68,12 @@ class OpenVPNAuthenticator(object):
 
 		while True:
 			char = self.sock.recv(1)
+
+			# Break if we could not read from the socket
+			if not char:
+				raise EOFError("Could not read from socket")
+
+			# Append to buffer
 			buf.append(char)
 
 			# Reached end of line
@@ -112,7 +118,7 @@ class OpenVPNAuthenticator(object):
 					self._client_event(line)
 
 		# Terminate the daemon when it loses its connection to the OpenVPN daemon
-		except ConnectionResetError as e:
+		except (ConnectionResetError, EOFError) as e:
 			log.error("Connection to OpenVPN has been lost: %s" % e)
 
 		log.info("OpenVPN Authenticator terminated")