OG-408 forwarder validUntil (#582) + truffle solc compiler workaround

* OG-408: forwarder validUntil

make sure forwrader signed requests don't last forever, by adding
"validUntil" block number.

client defaults to 6000 blocks (~1 day).

relayer validates request is at least 3000 blocks into the future.

* fix truffle's "missing compiler" bug

.circleci/config.yml

@@ -8,6 +8,10 @@ jobs: # a collection of steps
     steps: # a collection of executable commands
       - checkout # special step to check out source code to working directory
 
+      - run: 
+          name: download missing solc for truffle
+          command: ./scripts/download-solc
+
       - restore_cache: # special step to restore the dependency cache
           key: dependency-cache-{{ checksum "package.json" }}-yarn2
       - run:

contracts/forwarder/Forwarder.sol

@@ -8,7 +8,7 @@ import "./IForwarder.sol";
 contract Forwarder is IForwarder {
     using ECDSA for bytes32;
 
-    string public constant GENERIC_PARAMS = "address from,address to,uint256 value,uint256 gas,uint256 nonce,bytes data";
+    string public constant GENERIC_PARAMS = "address from,address to,uint256 value,uint256 gas,uint256 nonce,bytes data,uint256 validUntil";
 
     string public constant EIP712_DOMAIN_TYPE = "EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)";
 
@@ -60,12 +60,15 @@ contract Forwarder is IForwarder {
 
         bytes memory callData = abi.encodePacked(req.data, req.from);
         require( gasleft()*63/64 >= req.gas, "FWD: insufficient gas" );
+        require(req.validUntil == 0 || req.validUntil > block.number, "FWD: request expired");
+
         // solhint-disable-next-line avoid-low-level-calls
         (success,ret) = req.to.call{gas : req.gas, value : req.value}(callData);
         if ( address(this).balance>0 ) {
             //can't fail: req.from signed (off-chain) the request, so it must be an EOA...
             payable(req.from).transfer(address(this).balance);
         }
+
         return (success,ret);
     }
 
@@ -114,11 +117,6 @@ contract Forwarder is IForwarder {
         emit RequestTypeRegistered(requestTypehash, requestType);
     }
 
-    event DomainRegistered(bytes32 indexed domainSeparator, bytes domainValue);
-
-    event RequestTypeRegistered(bytes32 indexed typeHash, string typeStr);
-
-
     function _verifySig(
         ForwardRequest calldata req,
         bytes32 domainSeparator,
@@ -155,7 +153,8 @@ contract Forwarder is IForwarder {
                 req.value,
                 req.gas,
                 req.nonce,
-                keccak256(req.data)
+                keccak256(req.data),
+                req.validUntil
             ),
             suffixData
         );

contracts/forwarder/IForwarder.sol

@@ -11,8 +11,13 @@ interface IForwarder {
         uint256 gas;
         uint256 nonce;
         bytes data;
+        uint64 validUntil;
     }
 
+    event DomainRegistered(bytes32 indexed domainSeparator, bytes domainValue);
+
+    event RequestTypeRegistered(bytes32 indexed typeHash, string typeStr);
+
     function getNonce(address from)
     external view
     returns(uint256);

contracts/utils/GsnEip712Library.sol

@@ -16,7 +16,7 @@ library GsnEip712Library {
     uint256 private constant MAX_RETURN_SIZE = 1024;
 
     //copied from Forwarder (can't reference string constants even from another library)
-    string public constant GENERIC_PARAMS = "address from,address to,uint256 value,uint256 gas,uint256 nonce,bytes data";
+    string public constant GENERIC_PARAMS = "address from,address to,uint256 value,uint256 gas,uint256 nonce,bytes data,uint256 validUntil";
 
     bytes public constant RELAYDATA_TYPE = "RelayData(uint256 gasPrice,uint256 pctRelayFee,uint256 baseRelayFee,address relayWorker,address paymaster,address forwarder,bytes paymasterData,uint256 clientId)";
 
@@ -56,7 +56,8 @@ library GsnEip712Library {
             req.request.value,
             req.request.gas,
             req.request.nonce,
-            req.request.data
+            req.request.data,
+            req.request.validUntil
         );
         suffixData = abi.encode(
             hashRelayData(req.relayData));

scripts/download-solc

@@ -0,0 +1,9 @@
+#!/bin/bash -xe
+FOLDER=~/.config/truffle/compilers/node_modules/
+SOLC=soljson-v0.7.6+commit.7338295f.js
+mkdir -p $FOLDER
+
+COMPILER=$FOLDER/$SOLC
+curl -sL https://github.com/ethereum/solidity/releases/download/v0.7.6/soljson.js > $COMPILER
+md5sum $COMPILER | grep bd086ddf0f3585a0373c086e001982c3
+

src/common/EIP712/ForwardRequest.ts

@@ -8,4 +8,5 @@ export default interface ForwardRequest {
   value: IntString
   nonce: IntString
   gas: IntString
+  validUntil: IntString
 }

src/common/EIP712/TypedRequestData.ts

@@ -31,7 +31,8 @@ const ForwardRequestType = [
   { name: 'value', type: 'uint256' },
   { name: 'gas', type: 'uint256' },
   { name: 'nonce', type: 'uint256' },
-  { name: 'data', type: 'bytes' }
+  { name: 'data', type: 'bytes' },
+  { name: 'validUntil', type: 'uint256' }
 ]
 
 const RelayRequestType = [

src/common/Environments.ts

@@ -13,7 +13,7 @@ interface Environment {
 
 export const defaultRelayHubConfiguration: RelayHubConfiguration = {
   gasOverhead: 33346,
-  postOverhead: 13016,
+  postOverhead: 13302,
   gasReserve: 100000,
   maxWorkerCount: 10,
   minimumStake: 1e18.toString(),

src/common/types/RelayTransactionRequest.ts

@@ -24,7 +24,8 @@ export const RelayTransactionRequestShape = {
       data: ow.string,
       value: ow.string,
       nonce: ow.string,
-      gas: ow.string
+      gas: ow.string,
+      validUntil: ow.string
     },
     relayData: {
       gasPrice: ow.string,

src/relayclient/RelayClient.ts

@@ -35,6 +35,9 @@ import {
   GsnValidateRequestEvent
 } from './GsnEvents'
 
+// forwarder requests are signed with expiration time.
+const REQUEST_VALID_BLOCKS = 6000 // roughly a day
+
 // generate "approvalData" and "paymasterData" for a request.
 // both are bytes arrays. paymasterData is part of the client request.
 // approvalData is created after request is filled and signed.
@@ -306,6 +309,10 @@ export class RelayClient {
       throw new Error('Contract addresses are not initialized!')
     }
 
+    // valid that many blocks into the future.
+    const validUntilPromise = this.dependencies.contractInteractor.getBlockNumber()
+      .then((num: number) => (num + REQUEST_VALID_BLOCKS).toString())
+
     const senderNonce = await this.dependencies.contractInteractor.getSenderNonce(gsnTransactionDetails.from, forwarder)
     const relayWorker = relayInfo.pingResponse.relayWorkerAddress
     const gasPriceHex = gsnTransactionDetails.gasPrice
@@ -329,7 +336,8 @@ export class RelayClient {
         from: gsnTransactionDetails.from,
         value: value,
         nonce: senderNonce,
-        gas: gasLimit
+        gas: gasLimit,
+        validUntil: await validUntilPromise
       },
       relayData: {
         pctRelayFee: relayInfo.relayInfo.pctRelayFee,

src/relayserver/RelayServer.ts

@@ -126,7 +126,7 @@ export class RelayServer extends EventEmitter {
     }
   }
 
-  validateInput (req: RelayTransactionRequest): void {
+  validateInput (req: RelayTransactionRequest, currentBlockNumber: number): void {
     // Check that the relayHub is the correct one
     if (req.metadata.relayHubAddress !== this.relayHubContract.address) {
       throw new Error(
@@ -144,6 +144,13 @@ export class RelayServer extends EventEmitter {
       throw new Error(
         `Unacceptable gasPrice: relayServer's gasPrice:${this.gasPrice} request's gasPrice: ${req.relayRequest.relayData.gasPrice}`)
     }
+
+    // validate the validUntil is not too close
+    const expiredInBlocks = parseInt(req.relayRequest.request.validUntil) - currentBlockNumber
+    if (expiredInBlocks < this.config.requestMinValidBlocks) {
+      throw new Error(
+          `Request expired (or too close): expired in ${expiredInBlocks} blocks, we expect it to be valid for ${this.config.requestMinValidBlocks}`)
+    }
   }
 
   validateFees (req: RelayTransactionRequest): void {
@@ -279,7 +286,8 @@ returnValue        | ${viewRelayCallRet.returnValue}
       this.logger.error('Alerted state: slowing down traffic')
       await sleep(randomInRange(this.config.minAlertedDelayMS, this.config.maxAlertedDelayMS))
     }
-    this.validateInput(req)
+    const currentBlock = await this.contractInteractor.getBlockNumber()
+    this.validateInput(req, currentBlock)
     this.validateFees(req)
     await this.validateMaxNonce(req.metadata.relayMaxNonce)
 
@@ -298,7 +306,6 @@ returnValue        | ${viewRelayCallRet.returnValue}
 
     const method = this.relayHubContract.contract.methods.relayCall(
       acceptanceBudget, req.relayRequest, req.metadata.signature, req.metadata.approvalData, maxPossibleGas)
-    const currentBlock = await this.contractInteractor.getBlockNumber()
     const details: SendTransactionDetails =
       {
         signer: this.workerAddress,

src/relayserver/ServerConfigParams.ts

@@ -59,6 +59,7 @@ export interface ServerConfigParams {
   retryGasPriceFactor: number
   maxGasPrice: string
   defaultGasLimit: number
+  requestMinValidBlocks: number
 
   runPenalizer: boolean
   runPaymasterReputations: boolean
@@ -119,6 +120,8 @@ const serverDefaultConfiguration: ServerConfigParams = {
   retryGasPriceFactor: 1.2,
   defaultGasLimit: 500000,
   maxGasPrice: 100e9.toString(),
+
+  requestMinValidBlocks: 3000, // roughly 12 hours (half client's default of 6000 blocks
   runPaymasterReputations: true
 }
 
@@ -160,6 +163,7 @@ const ConfigParamsTypes = {
   managerTargetBalance: 'number',
   minHubWithdrawalBalance: 'number',
   defaultGasLimit: 'number',
+  requestMinValidBlocks: 'number',
 
   trustedPaymasters: 'list',
 

test/PaymasterCommitment.test.ts

@@ -62,7 +62,7 @@ Promise<{ req: RelayRequest, sig: PrefixedHexString }> {
 // - PM always pay for non-reverted TXs (either high or low gas use)
 // - if preRelayedCall reverts: PM always pay (=as long as commitment>preRelayedCallGasLimit)
 // - standard forwarder reverts: PM always pay (since commitment > gas of (preRelayedCall,forwarder))
-// - nonstandard forwardeR: PM pays above commitment
+// - nonstandard forwarder: PM pays above commitment
 // - trusted recipient: PM pays above commitment.
 contract('Paymaster Commitment', function ([_, relayOwner, relayManager, relayWorker, senderAddress, other]) { // eslint-disable-line no-unused-vars
   const RelayCallStatusCodes = {
@@ -146,7 +146,8 @@ contract('Paymaster Commitment', function ([_, relayOwner, relayManager, relayWo
           from: senderAddress,
           nonce: senderNonce,
           value: '0',
-          gas: gasLimit
+          gas: gasLimit,
+          validUntil: '0'
         },
         relayData: {
           pctRelayFee,
@@ -193,7 +194,7 @@ contract('Paymaster Commitment', function ([_, relayOwner, relayManager, relayWo
     it('paymaster should not change its acceptanceBudget before transaction', async () => {
       // the protocol of the relay to perform a view function of relayCall(), and then
       // issue it on-chain.
-      // this test comes to verify the paymaster didn't chagne its acceptanceBalance between these
+      // this test comes to verify the paymaster didn't change its acceptanceBalance between these
       // calls to a higher value.
       // it is assumed that the relay already made the view function and validated the acceptanceBalance to
       // be small, and now making a 2nd call on-chain, but with the acceptanceBalance as parameter.

test/RelayHub.test.ts

@@ -188,7 +188,8 @@ contract('RelayHub', function ([_, relayOwner, relayManager, relayWorker, sender
           from: senderAddress,
           nonce: senderNonce,
           value: '0',
-          gas: gasLimit
+          gas: gasLimit,
+          validUntil: '0'
         },
         relayData: {
           pctRelayFee,

test/RelayHubGasCalculations.test.ts

@@ -38,7 +38,7 @@ contract('RelayHub gas calculations', function ([_, relayOwner, relayWorker, rel
 
   const senderNonce = new BN('0')
   const magicNumbers = {
-    pre: 5451,
+    pre: 5429,
     post: 1639
   }
 
@@ -87,7 +87,8 @@ contract('RelayHub gas calculations', function ([_, relayOwner, relayWorker, rel
         from: senderAddress,
         nonce: senderNonce.toString(),
         value: '0',
-        gas: gasLimit.toString()
+        gas: gasLimit.toString(),
+        validUntil: '0'
       },
       relayData: {
         baseRelayFee: baseFee.toString(),
@@ -298,7 +299,8 @@ contract('RelayHub gas calculations', function ([_, relayOwner, relayWorker, rel
               from: senderAddress,
               nonce: senderNonce,
               value: '0',
-              gas: gasLimit.toString()
+              gas: gasLimit.toString(),
+              validUntil: '0'
             },
             relayData: {
               baseRelayFee: '0',
@@ -364,7 +366,8 @@ contract('RelayHub gas calculations', function ([_, relayOwner, relayWorker, rel
                   from: senderAddress,
                   nonce: senderNonce,
                   value: '0',
-                  gas: gasLimit.toString()
+                  gas: gasLimit.toString(),
+                  validUntil: '0'
                 },
                 relayData: {
                   baseRelayFee,

test/RelayHubPenalizations.test.ts

@@ -100,7 +100,8 @@ contract('RelayHub Penalizations', function ([_, relayOwner, relayWorker, otherR
         from: sender,
         nonce: '0',
         value: '0',
-        gas: gasLimit.toString()
+        gas: gasLimit.toString(),
+        validUntil: '0'
       },
       relayData: {
         gasPrice: gasPrice.toString(),
@@ -354,7 +355,8 @@ contract('RelayHub Penalizations', function ([_, relayOwner, relayWorker, otherR
               from: sender,
               nonce: senderNonce.toString(),
               value: '0',
-              gas: gasLimit.toString()
+              gas: gasLimit.toString(),
+              validUntil: '0'
             },
             relayData: {
               gasPrice: gasPrice.toString(),
@@ -458,7 +460,8 @@ contract('RelayHub Penalizations', function ([_, relayOwner, relayWorker, otherR
             from: encodedCallArgs.sender,
             nonce: encodedCallArgs.nonce.toString(),
             value: '0',
-            gas: encodedCallArgs.gasLimit.toString()
+            gas: encodedCallArgs.gasLimit.toString(),
+            validUntil: '0'
           },
           relayData: {
             baseRelayFee: encodedCallArgs.baseFee.toString(),

test/TestBatchForwarder.test.ts

@@ -66,7 +66,8 @@ contract('BatchForwarder', ([from, relayManager, relayWorker, relayOwner]) => {
         from,
         nonce: '1',
         value: '0',
-        gas: 1e6.toString()
+        gas: 1e6.toString(),
+        validUntil: '0'
       },
       relayData: {
         pctRelayFee: '1',

test/Utils.test.ts

@@ -76,7 +76,8 @@ contract('Utils', function (accounts) {
           from: senderAddress,
           nonce: senderNonce,
           value: '0',
-          gas: gasLimit
+          gas: gasLimit,
+          validUntil: '0'
         },
         relayData: {
           gasPrice,

test/common/ContractInteractor.test.ts

@@ -72,7 +72,8 @@ contract('ContractInteractor', function (accounts) {
           from: constants.ZERO_ADDRESS,
           nonce: '1',
           value: '0',
-          gas: '50000'
+          gas: '50000',
+          validUntil: '0'
         },
         relayData: {
           gasPrice: '1',
@@ -113,7 +114,8 @@ contract('ContractInteractor', function (accounts) {
           from: addr(2),
           nonce: '1',
           value: '0',
-          gas: '50000'
+          gas: '50000',
+          validUntil: '0'
         },
         relayData: {
           gasPrice: '1',