fix(commitment-lock): reject type script on CKB successor

checksums.txt

@@ -1,4 +1,4 @@
-a7762721ef239b15adbdddca8d772db6e1c001d9f81e23ccc74e1392329931d7  build/release/commitment-lock
-ecf31c4c024d5f7339f56e19f0e7c2bdce6188b6c069752faefa5313f7ae534d  build/release/commitment-lock.debug
+cd44265503d53937865cae53a4e8e3ff8800aed667806d630c3f4cb4f65b9772  build/release/commitment-lock
+1a962b0db2d899a7d9159305f3b505dc887a8c38a13a1db4bf054a79f6c22fc5  build/release/commitment-lock.debug
 831f164aad1509db5483dd50c50bf4ed5cb6601f941600287ffdb5e79a29cf9e  build/release/funding-lock
 291bdd4a48783ce75012a6e21935090806014d33bf6c52b1b2374e8feeaa91f0  build/release/funding-lock.debug

contracts/commitment-lock/src/main.rs

@@ -550,6 +550,11 @@ fn auth() -> Result<(), Error> {
                     }
                 }
                 None => {
+                    // A CKB successor must not acquire a type script.
+                    if load_cell_type(0, Source::Output)?.is_some() {
+                        return Err(Error::OutputTypeError);
+                    }
+
                     // verify the first output cell's capacity is correct
                     let output_capacity = load_cell_capacity(0, Source::Output)? as u128;
                     if output_capacity != new_amount {

tests/src/tests.rs

@@ -436,7 +436,7 @@ fn test_commitment_lock_no_pending_htlcs() {
         .build();
     let auth_dep = CellDep::new_builder().out_point(auth_out_point).build();
     let always_success_dep = CellDep::new_builder()
-        .out_point(always_success_out_point)
+        .out_point(always_success_out_point.clone())
         .build();
     let cell_deps = vec![commitment_lock_dep, auth_dep, always_success_dep].pack();
 
@@ -595,6 +595,43 @@ fn test_commitment_lock_no_pending_htlcs() {
         .expect("pass verification");
     println!("consume cycles: {}", cycles);
 
+    // A CKB successor must not gain an unexpected type script.
+    let unexpected_type = context
+        .build_script(&always_success_out_point, Bytes::new())
+        .expect("type script");
+    let typed_output = outputs[0]
+        .clone()
+        .as_builder()
+        .type_(Some(unexpected_type).pack())
+        .build();
+    let typed_tx = tx
+        .as_advanced_builder()
+        .set_outputs(vec![typed_output])
+        .build();
+    let typed_signature = local_settlement_key
+        .0
+        .sign_recoverable(&compute_tx_message(&typed_tx).into())
+        .unwrap()
+        .serialize();
+    let typed_witness = [
+        EMPTY_WITNESS_ARGS.to_vec(),
+        vec![0x01],
+        settlement_script.clone(),
+        vec![0xFF, 0x00],
+        typed_signature,
+    ]
+    .concat();
+    let typed_tx = typed_tx
+        .as_advanced_builder()
+        .witness(typed_witness.pack())
+        .build();
+    assert_script_error_code(
+        &context,
+        &typed_tx,
+        20,
+        "CKB successor with unexpected type script",
+    );
+
     // test with settlement unlock logic (remote settlement key)
     let input_out_point = context.create_cell(outputs[0].clone(), Bytes::new());