Merge pull request #13 from ermos/12-fix-return_statements-issue-in-i…

…nternalpkggoliathdecryptgo

refact(goliath): create a function for remove padding

internal/pkg/goliath/decrypt.go

@@ -47,12 +47,5 @@ func DecryptData(content string, masterPassword string) (b []byte, err error) {
 	plainText := make([]byte, len(cipherText))
 	mode.CryptBlocks(plainText, cipherText)
 
-	// Remove padding
-	padLen := int(plainText[len(plainText)-1])
-	if padLen > aes.BlockSize || padLen > len(plainText) {
-		return nil, errors.New("invalid padding")
-	}
-
-	b = plainText[:len(plainText)-padLen]
-	return
+	return removePaddingPKCS5(plainText)
 }

internal/pkg/goliath/encrypt.go

@@ -35,7 +35,7 @@ func EncryptData(data []byte, masterPassword string) (s string, err error) {
 	}
 
 	blockSize := block.BlockSize()
-	paddedData := paddingPKCS5(data, blockSize)
+	paddedData := addPaddingPKCS5(data, blockSize)
 	cipherText := make([]byte, len(paddedData))
 	mode := cipher.NewCBCEncrypter(block, iv)
 	mode.CryptBlocks(cipherText, paddedData)

internal/pkg/goliath/utils.go

@@ -2,18 +2,30 @@ package goliath
 
 import (
 	"bytes"
+	"crypto/aes"
 	"crypto/hmac"
 	"crypto/sha256"
+	"errors"
 )
 
-// paddingPKCS5 adds PKCS#5 padding to the given data to make its length a multiple of the block size.
+// addPaddingPKCS5 adds PKCS#5 padding to the given data to make its length a multiple of the block size.
 // https://en.wikipedia.org/wiki/Padding_(cryptography)#PKCS#5_and_PKCS#7
-func paddingPKCS5(data []byte, blockSize int) []byte {
+func addPaddingPKCS5(data []byte, blockSize int) []byte {
 	padLen := blockSize - len(data)%blockSize
 	pad := bytes.Repeat([]byte{byte(padLen)}, padLen)
 	return append(data, pad...)
 }
 
+// removePaddingPKCS5 remove PKCS#5 padding.
+func removePaddingPKCS5(data []byte) ([]byte, error) {
+	padLen := int(data[len(data)-1])
+	if padLen > aes.BlockSize || padLen > len(data) {
+		return nil, errors.New("invalid padding")
+	}
+
+	return data[:len(data)-padLen], nil
+}
+
 // computeHMAC computes the HMAC-SHA256 tag for the given data and key.
 func computeHMAC(data []byte, key []byte) []byte {
 	mac := hmac.New(sha256.New, key)