Chaos Pallet

The Chaos module is used to inject chaos into a Substrate Runtime and intentionally break things.

Overview

The Chaos module provides functions for:

• Make Substrate Runtimes behave in ways that they're not supposed to.
• Explore Runtime edge cases.
• Explore Extrinsic weights and their economic implications.
• Expose Runtime Attack Vectors.

Dispatchable Functions

overflow_adder

Inspired by overflow extrinsic implementation from Alexander Popiak's how-not-to-build-a-pallet, performs an unchecked sum over the Adder storage object. If the result is above 4_294_967_296, then Adder overflows.

This extrinsic illustrates the importance of using safe operations such as checked_add, checked_sub and their variants from substrate_primitives::U256.

clear_adder

Simply clears the Adder storage object so that unwrap_add can illustrate bad unwraps.

dragBlockUnitWeight(n)

Injects a heavy computation payload into the runtime, effectively dragging block production by calculating hashes in a loop (n times), with constant unitary extrinsic weight.

This extrinsic illustrates the importance of proper weight design.

Usage

chaoscope provides a CLI utility to automate interaction with pallet-chaos on a local setup.

1. In case you want to interact with it manually, follow the steps below.
2. Include pallet-chaos to a substrate-node-template, build it, and start the chain:

$ ./target/release/node-template --dev --tmp

3. On PolkadotJS, connect to DEVELOPMENT Chain (ws://127.0.0.1:9944).
4. Open Developer->Extrinsics.

Overflowing

On a browser new tab, open Developer->Chain state. Then choose chaos-> adder(), and click the + sign. This is how you'll monitor the Adder storage object.

On the extrinsics tab you had previously open, choose chaos->overflowAdder(n).

While monitoring adder() on the Chain state tab, keep adding numbers at will, until you reach 4_294_967_296.

Observe what happens after you add above this value, and imagine what would be the implications if Adder actually represented something meaningful in your chain.

Dragging Blocks

Choose chaos->dragBlockUnitWeight(n).

Here's where the experimentation starts. Choose different values for n, call Submit Transaction and observe the effects on block production.

License

AGPL-3.0