RNG Fallback

contracts/CHANGELOG.md

@@ -9,6 +9,11 @@ The format is based on [Common Changelog](https://common-changelog.org/).
 ### Changed
 
 - **Breaking:** Replace `require()` with `revert()` and custom errors outside KlerosCore for consistency and smaller bytecode ([#2084](https://github.com/kleros/kleros-v2/issues/2084))
+- **Breaking:** Rename the interface from `RNG` to `IRNG` ([#2054](https://github.com/kleros/kleros-v2/issues/2054))
+- **Breaking:** Remove the `_block` parameter from `IRNG.requestRandomness()` and `IRNG.receiveRandomness()`, not needed for the primary VRF-based RNG ([#2054](https://github.com/kleros/kleros-v2/issues/2054))
+- Make the primary VRF-based RNG fall back to `BlockhashRNG` if the VRF request is not fulfilled within a timeout ([#2054](https://github.com/kleros/kleros-v2/issues/2054))
+- Authenticate the calls to the RNGs to prevent 3rd parties from depleting the Chainlink VRF subscription funds ([#2054](https://github.com/kleros/kleros-v2/issues/2054))
+- Use `block.timestamp` rather than `block.number` for `BlockhashRNG` for better reliability on Arbitrum as block production is sporadic depending on network conditions. ([#2054](https://github.com/kleros/kleros-v2/issues/2054))
 - Set the Hardhat Solidity version to v0.8.30 and enable the IR pipeline ([#2069](https://github.com/kleros/kleros-v2/issues/2069))
 - Set the Foundry Solidity version to v0.8.30 and enable the IR pipeline ([#2073](https://github.com/kleros/kleros-v2/issues/2073))
 - Widen the allowed solc version to any v0.8.x for the interfaces only ([#2083](https://github.com/kleros/kleros-v2/issues/2083))

contracts/deploy/00-home-chain-arbitration-neo.ts

@@ -6,13 +6,12 @@ import { changeCurrencyRate } from "./utils/klerosCoreHelper";
 import { HomeChains, isSkipped, isDevnet, PNK, ETH } from "./utils";
 import { getContractOrDeploy, getContractOrDeployUpgradable } from "./utils/getContractOrDeploy";
 import { deployERC20AndFaucet, deployERC721 } from "./utils/deployTokens";
-import { ChainlinkRNG, DisputeKitClassic, KlerosCoreNeo } from "../typechain-types";
+import { ChainlinkRNG, DisputeKitClassic, KlerosCoreNeo, RNGWithFallback } from "../typechain-types";
 
 const deployArbitration: DeployFunction = async (hre: HardhatRuntimeEnvironment) => {
   const { ethers, deployments, getNamedAccounts, getChainId } = hre;
   const { deploy } = deployments;
   const { ZeroAddress } = hre.ethers;
-  const RNG_LOOKAHEAD = 20;
 
   // fallback to hardhat node signers on local network
   const deployer = (await getNamedAccounts()).deployer ?? (await hre.ethers.getSigners())[0].address;
@@ -45,7 +44,7 @@ const deployArbitration: DeployFunction = async (hre: HardhatRuntimeEnvironment)
   const devnet = isDevnet(hre.network);
   const minStakingTime = devnet ? 180 : 1800;
   const maxFreezingTime = devnet ? 600 : 1800;
-  const rng = (await ethers.getContract("ChainlinkRNG")) as ChainlinkRNG;
+  const rngWithFallback = await ethers.getContract<RNGWithFallback>("RNGWithFallback");
   const maxStakePerJuror = PNK(2_000);
   const maxTotalStaked = PNK(2_000_000);
   const sortitionModule = await deployUpgradable(deployments, "SortitionModuleNeo", {
@@ -55,8 +54,7 @@ const deployArbitration: DeployFunction = async (hre: HardhatRuntimeEnvironment)
       klerosCoreAddress,
       minStakingTime,
       maxFreezingTime,
-      rng.target,
-      RNG_LOOKAHEAD,
+      rngWithFallback.target,
       maxStakePerJuror,
       maxTotalStaked,
     ],
@@ -94,11 +92,11 @@ const deployArbitration: DeployFunction = async (hre: HardhatRuntimeEnvironment)
     await disputeKitContract.changeCore(klerosCore.address);
   }
 
-  // rng.changeSortitionModule() only if necessary
-  const rngSortitionModule = await rng.sortitionModule();
-  if (rngSortitionModule !== sortitionModule.address) {
-    console.log(`rng.changeSortitionModule(${sortitionModule.address})`);
-    await rng.changeSortitionModule(sortitionModule.address);
+  // rngWithFallback.changeConsumer() only if necessary
+  const rngConsumer = await rngWithFallback.consumer();
+  if (rngConsumer !== sortitionModule.address) {
+    console.log(`rngWithFallback.changeConsumer(${sortitionModule.address})`);
+    await rngWithFallback.changeConsumer(sortitionModule.address);
   }
 
   const core = (await hre.ethers.getContract("KlerosCoreNeo")) as KlerosCoreNeo;

contracts/deploy/00-home-chain-arbitration.ts

@@ -6,13 +6,12 @@ import { changeCurrencyRate } from "./utils/klerosCoreHelper";
 import { HomeChains, isSkipped, isDevnet, PNK, ETH, Courts } from "./utils";
 import { getContractOrDeploy, getContractOrDeployUpgradable } from "./utils/getContractOrDeploy";
 import { deployERC20AndFaucet } from "./utils/deployTokens";
-import { ChainlinkRNG, DisputeKitClassic, KlerosCore } from "../typechain-types";
+import { ChainlinkRNG, DisputeKitClassic, KlerosCore, RNGWithFallback } from "../typechain-types";
 
 const deployArbitration: DeployFunction = async (hre: HardhatRuntimeEnvironment) => {
   const { ethers, deployments, getNamedAccounts, getChainId } = hre;
   const { deploy } = deployments;
   const { ZeroAddress } = hre.ethers;
-  const RNG_LOOKAHEAD = 20;
 
   // fallback to hardhat node signers on local network
   const deployer = (await getNamedAccounts()).deployer ?? (await hre.ethers.getSigners())[0].address;
@@ -50,10 +49,10 @@ const deployArbitration: DeployFunction = async (hre: HardhatRuntimeEnvironment)
   const devnet = isDevnet(hre.network);
   const minStakingTime = devnet ? 180 : 1800;
   const maxFreezingTime = devnet ? 600 : 1800;
-  const rng = (await ethers.getContract("ChainlinkRNG")) as ChainlinkRNG;
+  const rngWithFallback = await ethers.getContract<RNGWithFallback>("RNGWithFallback");
   const sortitionModule = await deployUpgradable(deployments, "SortitionModule", {
     from: deployer,
-    args: [deployer, klerosCoreAddress, minStakingTime, maxFreezingTime, rng.target, RNG_LOOKAHEAD],
+    args: [deployer, klerosCoreAddress, minStakingTime, maxFreezingTime, rngWithFallback.target],
     log: true,
   }); // nonce (implementation), nonce+1 (proxy)
 
@@ -80,18 +79,18 @@ const deployArbitration: DeployFunction = async (hre: HardhatRuntimeEnvironment)
   }); // nonce+2 (implementation), nonce+3 (proxy)
 
   // disputeKit.changeCore() only if necessary
-  const disputeKitContract = (await ethers.getContract("DisputeKitClassic")) as DisputeKitClassic;
+  const disputeKitContract = await ethers.getContract<DisputeKitClassic>("DisputeKitClassic");
   const currentCore = await disputeKitContract.core();
   if (currentCore !== klerosCore.address) {
     console.log(`disputeKit.changeCore(${klerosCore.address})`);
     await disputeKitContract.changeCore(klerosCore.address);
   }
 
-  // rng.changeSortitionModule() only if necessary
-  const rngSortitionModule = await rng.sortitionModule();
-  if (rngSortitionModule !== sortitionModule.address) {
-    console.log(`rng.changeSortitionModule(${sortitionModule.address})`);
-    await rng.changeSortitionModule(sortitionModule.address);
+  // rngWithFallback.changeConsumer() only if necessary
+  const rngConsumer = await rngWithFallback.consumer();
+  if (rngConsumer !== sortitionModule.address) {
+    console.log(`rngWithFallback.changeConsumer(${sortitionModule.address})`);
+    await rngWithFallback.changeConsumer(sortitionModule.address);
   }
 
   const core = (await hre.ethers.getContract("KlerosCore")) as KlerosCore;

contracts/deploy/00-home-chain-resolver.ts

@@ -1,7 +1,7 @@
 import { HardhatRuntimeEnvironment } from "hardhat/types";
 import { DeployFunction } from "hardhat-deploy/types";
 import { HomeChains, isSkipped } from "./utils";
-import { deployUpgradable } from "./utils/deployUpgradable";
+import { getContractOrDeploy } from "./utils/getContractOrDeploy";
 
 const deployArbitration: DeployFunction = async (hre: HardhatRuntimeEnvironment) => {
   const { deployments, getNamedAccounts, getChainId } = hre;
@@ -15,7 +15,7 @@ const deployArbitration: DeployFunction = async (hre: HardhatRuntimeEnvironment)
   const klerosCore = await deployments.get("KlerosCore");
   const disputeTemplateRegistry = await deployments.get("DisputeTemplateRegistry");
 
-  await deploy("DisputeResolver", {
+  await getContractOrDeploy(hre, "DisputeResolver", {
     from: deployer,
     args: [klerosCore.address, disputeTemplateRegistry.address],
     log: true,

contracts/deploy/00-chainlink-rng.ts → contracts/deploy/00-rng-chainlink.ts

@@ -2,10 +2,10 @@ import { HardhatRuntimeEnvironment } from "hardhat/types";
 import { DeployFunction } from "hardhat-deploy/types";
 import { HomeChains, isSkipped } from "./utils";
 import { getContractOrDeploy } from "./utils/getContractOrDeploy";
+import { RNGWithFallback } from "../typechain-types";
 
 const deployRng: DeployFunction = async (hre: HardhatRuntimeEnvironment) => {
-  const { deployments, getNamedAccounts, getChainId } = hre;
-  const { deploy } = deployments;
+  const { getNamedAccounts, getChainId, ethers } = hre;
 
   // fallback to hardhat node signers on local network
   const deployer = (await getNamedAccounts()).deployer ?? (await hre.ethers.getSigners())[0].address;
@@ -57,11 +57,16 @@ const deployRng: DeployFunction = async (hre: HardhatRuntimeEnvironment) => {
   const requestConfirmations = 200; // between 1 and 200 L2 blocks
   const callbackGasLimit = 100000;
 
-  await deploy("ChainlinkRNG", {
+  const oldRng = await ethers.getContractOrNull("ChainlinkRNG");
+  if (!oldRng) {
+    console.log("Register this Chainlink consumer here: http://vrf.chain.link/");
+  }
+
+  const rng = await getContractOrDeploy(hre, "ChainlinkRNG", {
     from: deployer,
     args: [
       deployer,
-      deployer, // The consumer is configured as the SortitionModule later
+      deployer, // The consumer is configured as the RNGWithFallback later
       ChainlinkVRFCoordinator.target,
       keyHash,
       subscriptionId,
@@ -70,6 +75,26 @@ const deployRng: DeployFunction = async (hre: HardhatRuntimeEnvironment) => {
     ],
     log: true,
   });
+
+  const fallbackTimeoutSeconds = 30 * 60; // 30 minutes
+  await getContractOrDeploy(hre, "RNGWithFallback", {
+    from: deployer,
+    args: [
+      deployer,
+      deployer, // The consumer is configured as the SortitionModule later
+      fallbackTimeoutSeconds,
+      rng.target,
+    ],
+    log: true,
+  });
+
+  // rng.changeConsumer() only if necessary
+  const rngWithFallback = await ethers.getContract<RNGWithFallback>("RNGWithFallback");
+  const rngConsumer = await rng.consumer();
+  if (rngConsumer !== rngWithFallback.target) {
+    console.log(`rng.changeConsumer(${rngWithFallback.target})`);
+    await rng.changeConsumer(rngWithFallback.target);
+  }
 };
 
 deployRng.tags = ["ChainlinkRNG"];

contracts/deploy/00-randomizer-rng.ts → contracts/deploy/00-rng-randomizer.ts

@@ -2,10 +2,10 @@ import { HardhatRuntimeEnvironment } from "hardhat/types";
 import { DeployFunction } from "hardhat-deploy/types";
 import { HomeChains, isSkipped } from "./utils";
 import { getContractOrDeploy } from "./utils/getContractOrDeploy";
+import { RNGWithFallback } from "../typechain-types";
 
 const deployRng: DeployFunction = async (hre: HardhatRuntimeEnvironment) => {
-  const { deployments, getNamedAccounts, getChainId } = hre;
-  const { deploy } = deployments;
+  const { getNamedAccounts, getChainId, ethers } = hre;
 
   // fallback to hardhat node signers on local network
   const deployer = (await getNamedAccounts()).deployer ?? (await hre.ethers.getSigners())[0].address;
@@ -20,11 +20,35 @@ const deployRng: DeployFunction = async (hre: HardhatRuntimeEnvironment) => {
     log: true,
   });
 
-  await getContractOrDeploy(hre, "RandomizerRNG", {
+  const rng = await getContractOrDeploy(hre, "RandomizerRNG", {
     from: deployer,
-    args: [deployer, deployer, randomizerOracle.target], // The consumer is configured as the SortitionModule later
+    args: [
+      deployer,
+      deployer, // The consumer is configured as the RNGWithFallback later
+      randomizerOracle.target,
+    ],
     log: true,
   });
+
+  const fallbackTimeoutSeconds = 30 * 60; // 30 minutes
+  await getContractOrDeploy(hre, "RNGWithFallback", {
+    from: deployer,
+    args: [
+      deployer,
+      deployer, // The consumer is configured as the SortitionModule later
+      fallbackTimeoutSeconds,
+      rng.target,
+    ],
+    log: true,
+  });
+
+  // rng.changeConsumer() only if necessary
+  const rngWithFallback = await ethers.getContract<RNGWithFallback>("RNGWithFallback");
+  const rngConsumer = await rng.consumer();
+  if (rngConsumer !== rngWithFallback.target) {
+    console.log(`rng.changeConsumer(${rngWithFallback.target})`);
+    await rng.changeConsumer(rngWithFallback.target);
+  }
 };
 
 deployRng.tags = ["RandomizerRNG"];

contracts/deploy/change-sortition-module-rng.ts

@@ -23,11 +23,11 @@ const task: DeployFunction = async (hre: HardhatRuntimeEnvironment) => {
     sortitionModule = await ethers.getContract<SortitionModule>("SortitionModule");
   }
 
-  console.log(`chainlinkRng.changeSortitionModule(${sortitionModule.target})`);
-  await chainlinkRng.changeSortitionModule(sortitionModule.target);
+  console.log(`chainlinkRng.changeConsumer(${sortitionModule.target})`);
+  await chainlinkRng.changeConsumer(sortitionModule.target);
 
-  console.log(`sortitionModule.changeRandomNumberGenerator(${chainlinkRng.target}, 0)`);
-  await sortitionModule.changeRandomNumberGenerator(chainlinkRng.target, 0);
+  console.log(`sortitionModule.changeRandomNumberGenerator(${chainlinkRng.target})`);
+  await sortitionModule.changeRandomNumberGenerator(chainlinkRng.target);
 };
 
 task.tags = ["ChangeSortitionModuleRNG"];