Fix nil pointer dereference on SSH key parser (#130)

* Fix nil pointer dereference on SSH key parser

* Restyled by gofmt

Co-authored-by: Restyled.io <commits@restyled.io>

Author: 0x2b3bfa0

iterative/utils/ssh.go

@@ -5,6 +5,7 @@ import (
 	"crypto/rsa"
 	"crypto/x509"
 	"encoding/pem"
+	"fmt"
 	"strings"
 	"time"
 
@@ -27,7 +28,11 @@ func PrivatePEM() (string, error) {
 }
 
 func PublicFromPrivatePEM(privateKey string) (string, error) {
-	block, _ := pem.Decode([]byte(privateKey))
+	block, rest := pem.Decode([]byte(privateKey))
+	if block == nil {
+		return "", fmt.Errorf("Invalid PEM on the SSH private key: %#v", rest)
+	}
+
 	key, err := x509.ParsePKCS1PrivateKey(block.Bytes)
 	if err != nil {
 		return "", err