Fix linter issues

.golangci.yml

@@ -30,10 +30,8 @@ linters:
     - depguard
     - dogsled
     - errcheck
-    - exhaustive
-    - exportloopref
+    - copyloopvar
     - gci
-    - godot
     - gofmt
     - goheader
     - goimports
@@ -51,6 +49,8 @@ linters:
     - unconvert
     - unused
     - whitespace
+#    - exhaustive
+#    - godot
 #    - cyclop
 #    - dupl
 #    - durationcheck

putty.go

@@ -442,16 +442,46 @@ func decryptCBC(cipherKey, cipherIV, macKey, ciphertext []byte) error {
 
 // validateHMAC validates PuTTY key HMAC with a hash function
 func (k Key) validateHMAC(hashFunc hash.Hash) error {
-	binary.Write(hashFunc, binary.BigEndian, uint32(len(k.Algo)))
-	hashFunc.Write([]byte(k.Algo))
-	binary.Write(hashFunc, binary.BigEndian, uint32(len(k.Encryption)))
-	hashFunc.Write([]byte(k.Encryption))
-	binary.Write(hashFunc, binary.BigEndian, uint32(len(k.Comment)))
-	hashFunc.Write([]byte(k.Comment))
-	binary.Write(hashFunc, binary.BigEndian, uint32(len(k.PublicKey)))
-	hashFunc.Write(k.PublicKey)
-	binary.Write(hashFunc, binary.BigEndian, uint32(len(k.PrivateKey)))
-	hashFunc.Write(k.PrivateKey)
+	err := binary.Write(hashFunc, binary.BigEndian, uint32(len(k.Algo)))
+	if err != nil {
+		return err
+	}
+	_, err = hashFunc.Write([]byte(k.Algo))
+	if err != nil {
+		return err
+	}
+	err = binary.Write(hashFunc, binary.BigEndian, uint32(len(k.Encryption)))
+	if err != nil {
+		return err
+	}
+	_, err = hashFunc.Write([]byte(k.Encryption))
+	if err != nil {
+		return err
+	}
+	err = binary.Write(hashFunc, binary.BigEndian, uint32(len(k.Comment)))
+	if err != nil {
+		return err
+	}
+	_, err = hashFunc.Write([]byte(k.Comment))
+	if err != nil {
+		return err
+	}
+	err = binary.Write(hashFunc, binary.BigEndian, uint32(len(k.PublicKey)))
+	if err != nil {
+		return err
+	}
+	_, err = hashFunc.Write(k.PublicKey)
+	if err != nil {
+		return err
+	}
+	err = binary.Write(hashFunc, binary.BigEndian, uint32(len(k.PrivateKey)))
+	if err != nil {
+		return err
+	}
+	_, err = hashFunc.Write(k.PrivateKey)
+	if err != nil {
+		return err
+	}
 
 	mac := hashFunc.Sum(nil)
 	if !bytes.Equal(mac, k.PrivateMac) {

putty_test.go

@@ -446,7 +446,6 @@ Comment: a@b`
 	if err == nil {
 		t.Errorf("Invalid key algorithm")
 	}
-
 }
 
 func TestKey_Load(t *testing.T) {

unmarshal.go

@@ -44,6 +44,7 @@ func parseField(v reflect.Value, src *bytes.Reader) error {
 			}
 		}
 		return nil
+	default:
 	}
 
 	switch fieldType {