signer/core: handle JSON unmarshal error (#19123)

signer/core/abihelper.go

@@ -177,7 +177,9 @@ func NewAbiDBFromFile(path string) (*AbiDb, error) {
 	if err != nil {
 		return nil, err
 	}
-	json.Unmarshal(raw, &db.db)
+	if err := json.Unmarshal(raw, &db.db); err != nil {
+		return nil, err
+	}
 	return db, nil
 }
 
@@ -192,14 +194,18 @@ func NewAbiDBFromFiles(standard, custom string) (*AbiDb, error) {
 	if err != nil {
 		return nil, err
 	}
-	json.Unmarshal(raw, &db.db)
+	if err := json.Unmarshal(raw, &db.db); err != nil {
+		return nil, err
+	}
 	// Custom file may not exist. Will be created during save, if needed
 	if _, err := os.Stat(custom); err == nil {
 		raw, err = ioutil.ReadFile(custom)
 		if err != nil {
 			return nil, err
 		}
-		json.Unmarshal(raw, &db.customdb)
+		if err := json.Unmarshal(raw, &db.customdb); err != nil {
+			return nil, err
+		}
 	}
 
 	return db, nil