meowlib/server/identity.go

package server

import (
	"encoding/json"
	"fmt"
	"io/ioutil"

	"forge.redroom.link/yves/meowlib"
	"github.com/ProtonMail/gopenpgp/v2/helper"
	"google.golang.org/protobuf/proto"
)

const key = "3pw0c8#6ZG8{75b5;3?fe80$2"

type Identity struct {
	ServerName string          `json:"servername,omitempty"`
	ServerDesc string          `json:"serverdesc,omitempty"`
	ServerKp   meowlib.KeyPair `json:"server_kp,omitempty"`
	Status     string          `json:"status,omitempty"`
	//	KnownServers ServerList `json:"known_servers,omitempty"`
}

func CreateIdentity(ServerName string, ServerDesc string) *Identity {
	var id Identity
	id.ServerName = ServerName
	id.ServerDesc = ServerDesc
	id.ServerKp = meowlib.NewKeyPair()
	return &id
}

func LoadIdentity(File string) (*Identity, error) {
	var id Identity
	indata, err := ioutil.ReadFile(File)
	if err != nil {
		return nil, err
	}
	pass, err := helper.DecryptMessageWithPassword([]byte(key), string(indata))
	if err != nil {
		return nil, err
	}
	err = json.Unmarshal([]byte(pass), &id)
	return &id, err
}

func (id *Identity) Save(file string) error {
	b, _ := json.Marshal(id)
	armor, err := helper.EncryptMessageWithPassword([]byte(key), string(b))
	if err != nil {
		return err
	}
	err = ioutil.WriteFile(file, []byte(armor), 0644)
	return err
}

//
// Inbound processing chain
//

// Unpack a protobuf received packed message
func (id *Identity) UnpackReceived(message []byte) (fromPublicKey string, encryptedMessage []byte, signature []byte, err error) {
	pmsg := &meowlib.PackedServerMessage{}
	if err := proto.Unmarshal(message, pmsg); err != nil {
		return "", nil, nil, err
	}
	return pmsg.From, pmsg.Payload, pmsg.Signature, nil
}

// AsymDecryptMessage reads a message from a specific client contact
func (id *Identity) AsymDecryptMessage(ClientPublicKey string, Message []byte, Signature []byte) (DecryptedMsg []byte, err error) {
	DecryptedMsg, err = meowlib.AsymDecryptAndCheck(id.ServerKp.Private, ClientPublicKey, Message, Signature)
	if err != nil {
		fmt.Println(err.Error())
		return nil, err
	}
	return DecryptedMsg, err
}

// Decode decrypted ToServerMessage
func (id *Identity) DeserializeToServerMessage(toServerMessage []byte) (*meowlib.ToServerMessage, error) {
	tsmsg := &meowlib.ToServerMessage{}
	if err := proto.Unmarshal(toServerMessage, tsmsg); err != nil {
		return nil, err
	}
	return tsmsg, nil
}

// Inbound helper function
func (id *Identity) ProcessInbound(message []byte) (*meowlib.ToServerMessage, error) {
	// Unpack
	srv_from, srv_encmsg, srv_signature, err := id.UnpackReceived(message)
	if err != nil {
		return nil, err
	}
	// Decrypt
	srv_clear, err := id.AsymDecryptMessage(srv_from, srv_encmsg, srv_signature)
	if err != nil {
		return nil, err
	}
	// Decode msg
	srv_msg, err := id.DeserializeToServerMessage(srv_clear)
	if err != nil {
		return nil, err
	}
	return srv_msg, nil
}

//
// Outbound processing chain
//

func (id *Identity) BuildSimpleAckResponseMessage(uuidToAck string) (fromServerMessage *meowlib.FromServerMessage, err error) {
	var msg meowlib.FromServerMessage
	msg.ServerPublicKey = id.ServerKp.Public
	msg.UuidAck = uuidToAck
	return &msg, nil
}

func (id *Identity) SerializeFromServerMessage(msg *meowlib.FromServerMessage) (encodedFromServerMessage []byte, err error) {
	out, err := proto.Marshal(msg)
	if err != nil {
		return nil, err
	}
	return out, nil
}

// AsymEncryptMessage prepares a message to send to a specific peer contact
func (id *Identity) AsymEncryptMessage(peerPublicKey string, Message []byte) (EncryptedMsg []byte, Signature []byte, err error) {
	EncryptedMsg, Signature, err = meowlib.AsymEncryptAndSign(peerPublicKey, id.ServerKp.Private, Message)
	if err != nil {
		fmt.Println(err.Error())
		return nil, nil, err
	}
	return EncryptedMsg, Signature, err
}

func (id *Identity) PackForSending(encryptedMessage []byte, signature []byte) (fromServerMessage []byte, err error) {
	var pmsg meowlib.PackedServerMessage
	pmsg.Payload = encryptedMessage
	pmsg.Signature = signature
	pmsg.From = id.ServerKp.Public
	out, err := proto.Marshal(&pmsg)
	if err != nil {
		return nil, err
	}
	return out, nil
}

// Outbound helper function
func (id *Identity) ProcessOut(peerPublicKey string, msg *meowlib.FromServerMessage) (fromServerMessage []byte, err error) {
	encoded_srv_fromServerMessage, err := id.SerializeFromServerMessage(msg)
	if err != nil {
		return nil, err
	}
	srv_resp, srv_respsig, err := id.AsymEncryptMessage(peerPublicKey, encoded_srv_fromServerMessage)
	if err != nil {
		return nil, err
	}
	resp, err := id.PackForSending(srv_resp, srv_respsig)
	if err != nil {
		return nil, err
	}
	return resp, nil
}