prevent zero networkID, closes #8345

Signed-off-by: Seun LanLege <[email protected]>

json/src/spec/params.rs

@@ -35,6 +35,7 @@ pub struct Params {
 
 	/// Network id.
 	#[serde(rename="networkID")]
+	#[serde(deserialize_with="uint::validate_non_zero")]
 	pub network_id: Uint,
 	/// Chain id.
 	#[serde(rename="chainID")]
@@ -208,4 +209,20 @@ mod tests {
 
 		let _deserialized: Params = serde_json::from_str(s).unwrap();
 	}
+
+	#[test]
+	#[should_panic(expected = "a non-zero value")]
+	fn test_non_zero_network_id() {
+		let s = r#"{
+			"maximumExtraDataSize": "0x20",
+			"networkID" : "0x0",
+			"subprotocolName" : "exp",
+			"minGasLimit": "0x1388",
+			"accountStartNonce": "0x01",
+			"gasLimitBoundDivisor": "0x20",
+			"maxCodeSize": "0x1000"
+		}"#;
+
+		let _deserialized: Params = serde_json::from_str(s).unwrap();
+	}
 }