Start refactoring

config/security/security.go

@@ -0,0 +1,118 @@
+package security
+
+import (
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/x509"
+	"encoding/pem"
+	"golang.org/x/crypto/ssh"
+	"log"
+	"os"
+	"path"
+)
+
+const (
+	defaultPrivateKeyName = "id_rsa"
+	defaultPublicKeyName  = "id_rsa.pub"
+)
+
+// GenerateNewRSAKey generates a new RSA key, writes it to a file and return the private key
+func GenerateNewRSAKey(savePath string, bitSize uint16) (*rsa.PrivateKey, error) {
+	pkPath := path.Join(savePath, defaultPrivateKeyName)
+	pubPath := path.Join(savePath, defaultPublicKeyName)
+
+	privateKey, err := generatePrivateKey(int(bitSize))
+	if err != nil {
+		return nil, err
+	}
+
+	publicKeyBytes, err := generatePublicKey(&privateKey.PublicKey)
+	if err != nil {
+		return nil, err
+	}
+
+	privateKeyBytes := encodePrivateKeyToPEM(privateKey)
+
+	if err := writeKeyToFile(privateKeyBytes, pkPath); err != nil {
+		return nil, err
+	}
+
+	if err := writeKeyToFile(publicKeyBytes, pubPath); err != nil {
+		return nil, err
+	}
+	return privateKey, nil
+}
+
+func LoadPrivateKey(folderPath string) (*rsa.PrivateKey, error) {
+	pkPath := path.Join(folderPath, defaultPrivateKeyName)
+	f, err := os.ReadFile(pkPath)
+	if err != nil {
+		return nil, err
+	}
+	block, _ := pem.Decode(f)
+	key, err := x509.ParsePKCS1PrivateKey(block.Bytes)
+	if err != nil {
+		return nil, err
+	}
+	return key, nil
+}
+
+func generatePrivateKey(bitSize int) (*rsa.PrivateKey, error) {
+	// Private Key generation
+	privateKey, err := rsa.GenerateKey(rand.Reader, bitSize)
+	if err != nil {
+		return nil, err
+	}
+
+	// Validate Private Key
+	err = privateKey.Validate()
+	if err != nil {
+		return nil, err
+	}
+
+	log.Println("Private Key generated")
+	return privateKey, nil
+}
+
+// encodePrivateKeyToPEM encodes Private Key from RSA to PEM format
+func encodePrivateKeyToPEM(privateKey *rsa.PrivateKey) []byte {
+	// Get ASN.1 DER format
+	privDER := x509.MarshalPKCS1PrivateKey(privateKey)
+
+	// pem.Block
+	privBlock := pem.Block{
+		Type:    "RSA PRIVATE KEY",
+		Headers: nil,
+		Bytes:   privDER,
+	}
+
+	// Private key in PEM format
+	privatePEM := pem.EncodeToMemory(&privBlock)
+
+	return privatePEM
+}
+
+// generatePublicKey take a rsa.PublicKey and return bytes suitable for writing to .pub file
+// returns in the format "ssh-rsa ..."
+func generatePublicKey(privatekey *rsa.PublicKey) ([]byte, error) {
+	publicRsaKey, err := ssh.NewPublicKey(privatekey)
+	if err != nil {
+		return nil, err
+	}
+
+	pubKeyBytes := ssh.MarshalAuthorizedKey(publicRsaKey)
+
+	log.Println("Public key generated")
+	return pubKeyBytes, nil
+}
+
+// writePemToFile writes keys to a file
+func writeKeyToFile(keyBytes []byte, saveFileTo string) error {
+	err := os.WriteFile(saveFileTo, keyBytes, 0600)
+	if err != nil {
+		return err
+	}
+
+	log.Printf("Key saved to: %s", saveFileTo)
+	return nil
+}