RMN home & remote contracts (#1308)

Co-authored-by: Ryan Hall <[email protected]>

contracts/.solhintignore

@@ -41,3 +41,7 @@
 # Always ignore vendor
 ./src/v0.8/vendor
 ./node_modules/
+
+# Ignore RMN contracts temporarily
+./src/v0.8/ccip/RMNRemote.sol
+./src/v0.8/ccip/RMNHome.sol

contracts/gas-snapshots/ccip.gas-snapshot

@@ -772,6 +772,7 @@ PriceRegistry_validatePoolReturnData:test_InvalidEVMAddressDestToken_Revert() (g
 PriceRegistry_validatePoolReturnData:test_SourceTokenDataTooLarge_Revert() (gas: 90819)
 PriceRegistry_validatePoolReturnData:test_TokenAmountArraysMismatching_Revert() (gas: 32771)
 PriceRegistry_validatePoolReturnData:test_WithSingleToken_Success() (gas: 31315)
+RMNHome:test() (gas: 186)
 RMN_constructor:test_Constructor_Success() (gas: 48838)
 RMN_getRecordedCurseRelatedOps:test_OpsPostDeployment() (gas: 19666)
 RMN_lazyVoteToCurseUpdate_Benchmark:test_VoteToCurseLazilyRetain3VotersUponConfigChange_gas() (gas: 152152)

contracts/src/v0.8/ccip/RMNHome.sol

@@ -0,0 +1,164 @@
+// SPDX-License-Identifier: BUSL-1.1
+pragma solidity ^0.8.24;
+
+import "@openzeppelin/contracts/access/Ownable2Step.sol";
+
+import {ITypeAndVersion} from "../shared/interfaces/ITypeAndVersion.sol";
+
+/// @notice Stores the home configuration for RMN, that is referenced by CCIP oracles, RMN nodes, and the RMNRemote
+/// contracts.
+contract RMNHome is Ownable2Step, ITypeAndVersion {
+  /// @dev temp placeholder to exclude this contract from coverage
+  function test() public {}
+
+  string public constant override typeAndVersion = "RMNHome 1.6.0-dev";
+  uint256 public constant CONFIG_RING_BUFFER_SIZE = 2;
+
+  struct Node {
+    string peerId; // used for p2p communication, base58 encoded
+    bytes32 offchainPublicKey; // observations are signed with this public key, and are only verified offchain
+  }
+
+  struct SourceChain {
+    uint64 chainSelector;
+    uint64[] observerNodeIndices; // indices into Config.nodes, strictly increasing
+    uint64 minObservers; // required to agree on an observation for this source chain
+  }
+
+  struct Config {
+    // No sorting requirement for nodes, but ensure that SourceChain.observerNodeIndices in the home chain config &
+    // Signer.nodeIndex in the remote chain configs are appropriately updated when changing this field
+    Node[] nodes;
+    // Should be in ascending order of chainSelector
+    SourceChain[] sourceChains;
+  }
+
+  struct VersionedConfig {
+    uint32 version;
+    Config config;
+  }
+
+  function _configDigest(VersionedConfig memory versionedConfig) internal pure returns (bytes32) {
+    uint256 h = uint256(keccak256(abi.encode(versionedConfig)));
+    uint256 prefixMask = type(uint256).max << (256 - 16); // 0xFFFF00..00
+    uint256 prefix = 0x000b << (256 - 16); // 0x000b00..00
+    return bytes32((prefix & prefixMask) | (h & ~prefixMask));
+  }
+
+  // if we were to have VersionedConfig instead of Config in the ring buffer, we couldn't assign directly to it in
+  // setConfig without via-ir
+  uint32[CONFIG_RING_BUFFER_SIZE] s_configCounts; // s_configCounts[i] == 0 iff s_configs[i] is unusable
+  Config[CONFIG_RING_BUFFER_SIZE] s_configs;
+  uint256 s_latestConfigIndex;
+  bytes32 s_latestConfigDigest;
+
+  /// @param revokePastConfigs if one wants to revoke all past configs, because some past config is faulty
+  function setConfig(Config calldata newConfig, bool revokePastConfigs) external onlyOwner {
+    // sanity checks
+    {
+      // no peerId or offchainPublicKey is duplicated
+      for (uint256 i = 0; i < newConfig.nodes.length; ++i) {
+        for (uint256 j = i + 1; j < newConfig.nodes.length; ++j) {
+          if (keccak256(abi.encode(newConfig.nodes[i].peerId)) == keccak256(abi.encode(newConfig.nodes[j].peerId))) {
+            revert DuplicatePeerId();
+          }
+          if (newConfig.nodes[i].offchainPublicKey == newConfig.nodes[j].offchainPublicKey) {
+            revert DuplicateOffchainPublicKey();
+          }
+        }
+      }
+
+      for (uint256 i = 0; i < newConfig.sourceChains.length; ++i) {
+        // source chains are in strictly increasing order of chain selectors
+        if (i > 0 && !(newConfig.sourceChains[i - 1].chainSelector < newConfig.sourceChains[i].chainSelector)) {
+          revert OutOfOrderSourceChains();
+        }
+
+        // all observerNodeIndices are valid
+        for (uint256 j = 0; j < newConfig.sourceChains[i].observerNodeIndices.length; ++j) {
+          if (
+            j > 0
+              && !(newConfig.sourceChains[i].observerNodeIndices[j - 1] < newConfig.sourceChains[i].observerNodeIndices[j])
+          ) {
+            revert OutOfOrderObserverNodeIndices();
+          }
+          if (!(newConfig.sourceChains[i].observerNodeIndices[j] < newConfig.nodes.length)) {
+            revert OutOfBoundsObserverNodeIndex();
+          }
+        }
+
+        // minObservers are tenable
+        if (!(newConfig.sourceChains[i].minObservers <= newConfig.sourceChains[i].observerNodeIndices.length)) {
+          revert MinObserversTooHigh();
+        }
+      }
+    }
+
+    uint256 oldConfigIndex = s_latestConfigIndex;
+    uint32 oldConfigCount = s_configCounts[oldConfigIndex];
+    uint256 newConfigIndex = (oldConfigIndex + 1) % CONFIG_RING_BUFFER_SIZE;
+
+    for (uint256 i = 0; i < CONFIG_RING_BUFFER_SIZE; ++i) {
+      if ((i == newConfigIndex || revokePastConfigs) && s_configCounts[i] > 0) {
+        emit ConfigRevoked(_configDigest(VersionedConfig({version: s_configCounts[i], config: s_configs[i]})));
+        delete s_configCounts[i];
+      }
+    }
+
+    uint32 newConfigCount = oldConfigCount + 1;
+    VersionedConfig memory newVersionedConfig = VersionedConfig({version: newConfigCount, config: newConfig});
+    bytes32 newConfigDigest = _configDigest(newVersionedConfig);
+    s_configs[newConfigIndex] = newConfig;
+    s_configCounts[newConfigIndex] = newConfigCount;
+    s_latestConfigIndex = newConfigIndex;
+    s_latestConfigDigest = newConfigDigest;
+    emit ConfigSet(newConfigDigest, newVersionedConfig);
+  }
+
+  /// @return configDigest will be zero in case no config has been set
+  function getLatestConfigDigestAndVersionedConfig()
+    external
+    view
+    returns (bytes32 configDigest, VersionedConfig memory)
+  {
+    return (
+      s_latestConfigDigest,
+      VersionedConfig({version: s_configCounts[s_latestConfigIndex], config: s_configs[s_latestConfigIndex]})
+    );
+  }
+
+  /// @notice The offchain code can use this to fetch an old config which might still be in use by some remotes
+  /// @dev Only to be called by offchain code, efficiency is not a concern
+  function getConfig(bytes32 configDigest) external view returns (VersionedConfig memory versionedConfig, bool ok) {
+    for (uint256 i = 0; i < CONFIG_RING_BUFFER_SIZE; ++i) {
+      if (s_configCounts[i] == 0) {
+        // unset config
+        continue;
+      }
+      VersionedConfig memory vc = VersionedConfig({version: s_configCounts[i], config: s_configs[i]});
+      if (_configDigest(vc) == configDigest) {
+        versionedConfig = vc;
+        ok = true;
+        break;
+      }
+    }
+  }
+
+  ///
+  /// Events
+  ///
+
+  event ConfigSet(bytes32 configDigest, VersionedConfig versionedConfig);
+  event ConfigRevoked(bytes32 configDigest);
+
+  ///
+  /// Errors
+  ///
+
+  error DuplicatePeerId();
+  error DuplicateOffchainPublicKey();
+  error OutOfOrderSourceChains();
+  error OutOfOrderObserverNodeIndices();
+  error OutOfBoundsObserverNodeIndex();
+  error MinObserversTooHigh();
+}

contracts/src/v0.8/ccip/RMNRemote.sol

@@ -0,0 +1,167 @@
+// SPDX-License-Identifier: BUSL-1.1
+pragma solidity ^0.8.24;
+
+import "@openzeppelin/contracts/access/Ownable2Step.sol";
+
+import {ITypeAndVersion} from "../shared/interfaces/ITypeAndVersion.sol";
+
+bytes32 constant RMN_V1_6_ANY2EVM_REPORT = keccak256("RMN_V1_6_ANY2EVM_REPORT");
+
+/// @notice This contract supports verification of RMN reports for any Any2EVM OffRamp.
+contract RMNRemote is Ownable2Step, ITypeAndVersion {
+  /// @dev temp placeholder to exclude this contract from coverage
+  function test() public {}
+
+  string public constant override typeAndVersion = "RMNRemote 1.6.0-dev";
+
+  uint64 internal immutable i_chainSelector;
+
+  constructor(uint64 chainSelector) {
+    i_chainSelector = chainSelector;
+  }
+
+  struct Signer {
+    address onchainPublicKey; // for signing reports
+    uint64 nodeIndex; // maps to nodes in home chain config, should be strictly increasing
+  }
+
+  struct Config {
+    bytes32 rmnHomeContractConfigDigest;
+    Signer[] signers;
+    uint64 minSigners;
+  }
+
+  struct VersionedConfig {
+    uint32 version;
+    Config config;
+  }
+
+  Config s_config;
+  uint32 s_configCount;
+
+  mapping(address signer => bool exists) s_signers; // for more gas efficient verify
+
+  function setConfig(Config calldata newConfig) external onlyOwner {
+    // sanity checks
+    {
+      // signers are in ascending order of nodeIndex
+      for (uint256 i = 1; i < newConfig.signers.length; ++i) {
+        if (!(newConfig.signers[i - 1].nodeIndex < newConfig.signers[i].nodeIndex)) {
+          revert InvalidSignerOrder();
+        }
+      }
+
+      // minSigners is tenable
+      if (!(newConfig.minSigners <= newConfig.signers.length)) {
+        revert MinSignersTooHigh();
+      }
+    }
+
+    // clear the old signers
+    {
+      Config storage oldConfig = s_config;
+      while (oldConfig.signers.length > 0) {
+        delete s_signers[oldConfig.signers[oldConfig.signers.length - 1].onchainPublicKey];
+        oldConfig.signers.pop();
+      }
+    }
+
+    // set the new signers
+    {
+      for (uint256 i = 0; i < newConfig.signers.length; ++i) {
+        if (s_signers[newConfig.signers[i].onchainPublicKey]) {
+          revert DuplicateOnchainPublicKey();
+        }
+        s_signers[newConfig.signers[i].onchainPublicKey] = true;
+      }
+    }
+
+    s_config = newConfig;
+    uint32 newConfigCount = ++s_configCount;
+    emit ConfigSet(VersionedConfig({version: newConfigCount, config: newConfig}));
+  }
+
+  function getVersionedConfig() external view returns (VersionedConfig memory) {
+    return VersionedConfig({version: s_configCount, config: s_config});
+  }
+
+  /// @notice The part of the LaneUpdate for a fixed destination chain and OffRamp, to avoid verbosity in Report
+  struct DestLaneUpdate {
+    uint64 sourceChainSelector;
+    bytes onrampAddress; // generic, to support arbitrary sources; for EVM2EVM, use abi.encodePacked
+    uint64 minMsgNr;
+    uint64 maxMsgNr;
+    bytes32 root;
+  }
+
+  struct Report {
+    uint256 destChainId; // to guard against chain selector misconfiguration
+    uint64 destChainSelector;
+    address rmnRemoteContractAddress;
+    address offrampAddress;
+    bytes32 rmnHomeContractConfigDigest;
+    DestLaneUpdate[] destLaneUpdates;
+  }
+
+  struct Signature {
+    bytes32 r;
+    bytes32 s;
+  }
+
+  /// @notice Verifies signatures of RMN nodes, on dest lane updates as provided in the CommitReport
+  /// @param destLaneUpdates must be well formed, and is a representation of the CommitReport received from the oracles
+  /// @param signatures must be sorted in ascending order by signer address
+  /// @dev Will revert if verification fails. Needs to be called by the OffRamp for which the signatures are produced,
+  /// otherwise verification will fail.
+  function verify(DestLaneUpdate[] memory destLaneUpdates, Signature[] memory signatures) external view {
+    if (s_configCount == 0) {
+      revert ConfigNotSet();
+    }
+
+    bytes32 signedHash = keccak256(
+      abi.encode(
+        RMN_V1_6_ANY2EVM_REPORT,
+        Report({
+          destChainId: block.chainid,
+          destChainSelector: i_chainSelector,
+          rmnRemoteContractAddress: address(this),
+          offrampAddress: msg.sender,
+          rmnHomeContractConfigDigest: s_config.rmnHomeContractConfigDigest,
+          destLaneUpdates: destLaneUpdates
+        })
+      )
+    );
+
+    uint256 numSigners = 0;
+    address prevAddress = address(0);
+    for (uint256 i = 0; i < signatures.length; ++i) {
+      Signature memory sig = signatures[i];
+      address signerAddress = ecrecover(signedHash, 27, sig.r, sig.s);
+      if (signerAddress == address(0)) revert InvalidSignature();
+      if (!(prevAddress < signerAddress)) revert OutOfOrderSignatures();
+      if (!s_signers[signerAddress]) revert UnexpectedSigner();
+      prevAddress = signerAddress;
+      ++numSigners;
+    }
+    if (numSigners < s_config.minSigners) revert ThresholdNotMet();
+  }
+
+  ///
+  /// Events
+  ///
+
+  event ConfigSet(VersionedConfig versionedConfig);
+
+  ///
+  /// Errors
+  ///
+
+  error InvalidSignature();
+  error OutOfOrderSignatures();
+  error UnexpectedSigner();
+  error ThresholdNotMet();
+  error ConfigNotSet();
+  error InvalidSignerOrder();
+  error MinSignersTooHigh();
+  error DuplicateOnchainPublicKey();
+}