NOISSUE - Add AES support to RE (#143)

* AES RE support Lua script

* AES RE support Lua script

* AES support on RE

* AES Support on RE

* AES code change

* Modified AES script

* Modified AES script

* AES Go script

* AES Go script

* Update: String use to Byte use

* Update: AES Lua binding and Go script

* Update: AES Lua binding reviewed changes and Go script

* Reviewed Update: Lint Checking with code

* Reviewed Update: Lint Checking with code

* Reviewed Update: Lint Checking with code

* Reviewed Update: Lint Checking with code

* Reviewed Update: Lint Checking with code

* Reviewed Update: Lint Checking with code

* Reviewed Update: Lint Checking with code

* Reviewed Update: Lint Checking with code

* Reviewed Update: Lint Checking with code

* Reviewed Update: Lint Checking with code

* Fix remarks

Signed-off-by: Dusan Borovcanin <borovcanindusan1@gmail.com>

* Add IV size check

Signed-off-by: Dusan Borovcanin <borovcanindusan1@gmail.com>

* Add IV size check

Signed-off-by: Dusan Borovcanin <borovcanindusan1@gmail.com>

* Add IV size check

Signed-off-by: Dusan Borovcanin <borovcanindusan1@gmail.com>

* Fix variable names

Signed-off-by: Dusan Borovcanin <borovcanindusan1@gmail.com>

* Use common decode params

Signed-off-by: Dusan Borovcanin <borovcanindusan1@gmail.com>

---------

Signed-off-by: Dusan Borovcanin <borovcanindusan1@gmail.com>
Co-authored-by: Dusan Borovcanin <borovcanindusan1@gmail.com>

re/aes.go

@@ -0,0 +1,60 @@
+// Copyright (c) Abstract Machines
+// SPDX-License-Identifier: Apache-2.0
+
+package re
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+
+	"github.com/absmach/supermq/pkg/errors"
+)
+
+var (
+	errInvalidDataSize = errors.New("data is not a multiple of the block size")
+	errInvalidIVSize   = errors.New("size of the IV is not the same as block size")
+)
+
+// AES CBC-128 DECRYPTION requires 3 data fields
+// 1. Key (16 bytes)
+// 2. Initialization Vector (IV) (16 bytes)
+// 3. Encrypted Data (16 bytes or length multiple a of 16)
+// The encrypted data is divided into blocks of 16 bytes (128 bits) which then operated on with the IV and Key.
+func encrypt(key []byte, iv []byte, data []byte) ([]byte, error) {
+	if len(iv) != aes.BlockSize {
+		return nil, errInvalidIVSize
+	}
+	if len(data)%aes.BlockSize != 0 {
+		return nil, errInvalidDataSize
+	}
+
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		return nil, err
+	}
+
+	encrypted := make([]byte, len(data))
+	mode := cipher.NewCBCEncrypter(block, iv)
+	mode.CryptBlocks(encrypted, data)
+
+	return encrypted, nil
+}
+
+func decrypt(key []byte, iv []byte, encrypted []byte) ([]byte, error) {
+	if len(iv) != aes.BlockSize {
+		return nil, errInvalidIVSize
+	}
+	if len(encrypted)%aes.BlockSize != 0 {
+		return nil, errInvalidDataSize
+	}
+
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		return nil, err
+	}
+
+	mode := cipher.NewCBCDecrypter(block, iv)
+	decrypted := make([]byte, len(encrypted))
+	mode.CryptBlocks(decrypted, encrypted)
+	return decrypted, err
+}

re/bindings.go

@@ -7,6 +7,7 @@ import (
 	"bytes"
 	"context"
 	"encoding/gob"
+	"encoding/hex"
 	"encoding/json"
 
 	"github.com/absmach/magistrala/alarms"
@@ -15,6 +16,61 @@ import (
 	lua "github.com/yuin/gopher-lua"
 )
 
+func luaEncrypt(l *lua.LState) int {
+	key, iv, data, err := decodeParams(l)
+	if err != nil {
+		return 1
+	}
+	enc, err := encrypt(key, iv, data)
+	if err != nil {
+		l.RaiseError("Falied to encrypt: %v", err)
+		return 0
+	}
+	l.Push(lua.LString(hex.EncodeToString(enc)))
+	return 1
+}
+
+func luaDecrypt(l *lua.LState) int {
+	key, iv, data, err := decodeParams(l)
+	if err != nil {
+		return 1
+	}
+
+	dec, err := decrypt(key, iv, data)
+	if err != nil {
+		l.RaiseError("Falied to decrypt: %v", err)
+		return 0
+	}
+
+	l.Push(lua.LString(hex.EncodeToString(dec)))
+	return 1
+}
+
+func decodeParams(l *lua.LState) (key, iv, data []byte, err error) {
+	keyStr := l.ToString(1)
+	ivStr := l.ToString(2)
+	dataStr := l.ToString(3)
+
+	key, err = hex.DecodeString(keyStr)
+	if err != nil {
+		l.RaiseError("Failed to decode key: %v", err)
+		return
+	}
+
+	iv, err = hex.DecodeString(ivStr)
+	if err != nil {
+		l.RaiseError("Failed to decode IV: %v", err)
+		return
+	}
+
+	data, err = hex.DecodeString(dataStr)
+	if err != nil {
+		l.RaiseError("Failed to decode data: %v", err)
+		return
+	}
+	return
+}
+
 func (re *re) sendEmail(l *lua.LState) int {
 	recipientsTable := l.ToTable(1)
 	subject := l.ToString(2)

re/handlers.go

@@ -53,9 +53,11 @@ func (re *re) process(ctx context.Context, r Rule, msg *messaging.Message) error
 	// Set the message object as a Lua global variable.
 	l.SetGlobal("message", message)
 
-	// set the email function as a Lua global function.
+	// Set binding functions as a Lua global functions.
 	l.SetGlobal("send_email", l.NewFunction(re.sendEmail))
 	l.SetGlobal("send_alarm", l.NewFunction(re.sendAlarm(ctx, r.ID, msg)))
+	l.SetGlobal("aes_encrypt", l.NewFunction(luaEncrypt))
+	l.SetGlobal("aes_decrypt", l.NewFunction(luaDecrypt))
 
 	if err := l.DoString(r.Logic.Value); err != nil {
 		return err