Audit/9 5

[ameeshaagrawal]

Summary by CodeRabbit

• New Features

  • Introduced unified payload ID architecture for improved cross-chain routing and verification
  • Added gas account management system with escrow and wrapping capabilities
  • Implemented Solana integration support with signature verification and PDA utilities
  • Added message resolver for handling cross-domain messages

• Refactor

  • Redesigned fee management to gas-centric architecture
  • Updated switchboard system with registration and ID-based identification
  • Restructured payload and event signatures across core contracts
  • Refactored deployment and configuration data structures

• Documentation

  • Added comprehensive payload ID architecture documentation

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Walkthrough

This pull request performs a comprehensive architectural refactoring, transitioning from a request-based fee/credit management system to a payload-based gas account architecture. It removes legacy components (Credit, FeesManager, RequestHandler, FastSwitchboard, SocketFeeManager), introduces new gas management infrastructure (GasAccountManager, GasAccountToken, GasEscrow), adds Solana integration capabilities, and reshapes the core protocol to use 256-bit payload IDs with standardized encoding schemes across multiple switchboard and precompile implementations.

Changes

Cohort / File(s)	Summary
Environment & Config .env.sample, .gitignore, .prettierignore	Environment variable renamed (SOCKET_SIGNER_KEY → SOCKET_PRIVATE_KEY); ignore patterns expanded for deployments and coverage artifacts.
Documentation & Specs Errors.md, EventTopics.md, FunctionSignatures.md, PAYLOAD_ID_ARCHITECTURE.md	Comprehensive updates documenting new error types, event signatures, function interfaces, and unified 256-bit payload ID architecture with source/verification/pointer/reserved segments.
Removed Legacy Fees System contracts/evmx/fees/Credit.sol, contracts/evmx/fees/FeesManager.sol, contracts/protocol/SocketFeeManager.sol	Deleted entire credit/fee blocking infrastructure; replaced with new gas-based accounting.
New Gas Account System contracts/evmx/fees/GasAccountManager.sol, contracts/evmx/fees/GasAccountToken.sol, contracts/evmx/fees/GasEscrow.sol, contracts/evmx/fees/GasVault.sol, contracts/evmx/fees/MessageResolver.sol	New ERC20-based gas token (SGAS) with escrow-aware balance semantics, cross-chain gas operations, and message resolution workflow.
Address Resolution & Helpers contracts/evmx/helpers/AddressResolver.sol, contracts/evmx/helpers/AddressResolverUtil.sol	Replaced fee manager references with gas account manager, gas vault, and gas escrow getters; updated role constants and storage layout.
Solana Integration Libraries contracts/evmx/helpers/solana-utils/Ed25519.sol, contracts/evmx/helpers/solana-utils/Ed25519_pow.sol, contracts/evmx/helpers/solana-utils/Sha512.sol, contracts/evmx/helpers/solana-utils/SolanaPda.sol, contracts/evmx/helpers/solana-utils/SolanaSignature.sol, contracts/evmx/helpers/solana-utils/program-pda/GasStationPdas.sol	Complete Solana verification and PDA derivation utilities for cross-chain signature verification and account resolution.
Borsh Serde Infrastructure contracts/evmx/watcher/borsh-serde/BorshDecoder.sol, contracts/evmx/watcher/borsh-serde/BorshEncoder.sol, contracts/evmx/watcher/borsh-serde/BorshUtils.sol	Borsh serialization/deserialization support for Solana instruction encoding and generic schema handling.
Async Deployment & Promises contracts/evmx/helpers/AsyncDeployer.sol, contracts/evmx/helpers/AsyncPromise.sol, contracts/evmx/helpers/Forwarder.sol, contracts/evmx/helpers/ForwarderSolana.sol	Refactored to use bytes32 payload IDs instead of uint40 request counts; added deadline enforcement and Solana async call support.
Application Gateway Base contracts/evmx/base/AppGatewayBase.sol	Consolidated storage to OverrideParams; removed legacy queue/creation mechanisms; refactored to payload-driven submission via watcher.
Plug Implementations contracts/evmx/plugs/GasStation.sol (renamed from FeesPlug), contracts/protocol/base/PlugBase.sol, contracts/protocol/base/MessagePlugBase.sol	Renamed FeesPlug → GasStation; updated signatures to use switchboardId (uint32) instead of address; added sibling registration helpers.
Watcher Core contracts/evmx/watcher/Configurations.sol, contracts/evmx/watcher/Watcher.sol, contracts/evmx/watcher/RequestHandler.sol (removed)	RequestHandler.sol deleted; Watcher.sol rewritten for minimal payload tracking; Configurations shifted to IWatcher interface with signature-based validation.
Precompile Layer contracts/evmx/watcher/precompiles/ReadPrecompile.sol, contracts/evmx/watcher/precompiles/SchedulePrecompile.sol, contracts/evmx/watcher/precompiles/WritePrecompile.sol	Updated to RawPayload/Payload structures; added Solana instruction encoding; shifted from request-based to watcher-centric validation.
Switchboard Implementations contracts/protocol/switchboard/SwitchboardBase.sol, contracts/protocol/switchboard/EVMxSwitchboard.sol, contracts/protocol/switchboard/MessageSwitchboard.sol, contracts/protocol/switchboard/FastSwitchboard.sol (removed)	FastSwitchboard.sol deleted; new EVMxSwitchboard for fast EVMX attestations and MessageSwitchboard for bidirectional message switching with fee/sponsor management.
Core Protocol contracts/protocol/Socket.sol, contracts/protocol/SocketConfig.sol, contracts/protocol/SocketBatcher.sol, contracts/protocol/SocketUtils.sol, contracts/protocol/NetworkFeeCollector.sol	Refactored Socket to ExecutionParams/TransmissionParams; added switchboard registration and lifecycle; introduced network fee collection layer.
Interfaces contracts/evmx/interfaces/I*.sol, contracts/protocol/interfaces/I*.sol	Removed IFeesManager, IFeesPlug, ISocketFeeManager; added IGasAccountManager, IGasAccountToken, IGasEscrow, IGasVault, INetworkFeeCollector, IMessageHandler, IMessageTransmitter; updated IWatcher, ISocket, ISwitchboard to reflect payload-centric architecture.
Utility Libraries contracts/utils/common/Converters.sol, contracts/utils/common/DigestUtils.sol, contracts/utils/common/IdUtils.sol, contracts/utils/common/Structs.sol, contracts/utils/common/Errors.sol, contracts/utils/common/AccessRoles.sol, contracts/utils/common/Constants.sol, contracts/utils/OverrideParamsLib.sol, contracts/utils/Pausable.sol, contracts/utils/RescueFundsLib.sol	New ID encoding (source/verification/pointer), digest construction with length prefixes, escrow state tracking, ERC721 rescue support, comprehensive error set expansion, gas-centric access roles.
Deployment Configs deployments/dev_*.json, deployments/stage_*.json, deployments/prod_*.json	Extensive network expansion (30+ chains) with new contract mappings including FastSwitchboard, MessageSwitchboard, GasStation; SwitchboardIdToAddressMap structures.
Deprecated/Legacy deprecated/* (AuctionManager, CCTPSwitchboard, Configurations, ContractFactoryPlug, DeployForwarder, ForwarderV2, IAuctionManager, IRequestHandler, IWatcher, PromiseResolver, RequestHandler, Trigger, Watcher, WatcherBase, WatcherStorage), deprecated/script/*	Legacy request/auction/credit system preserved for reference; script utilities for counter apps and deposit flows.

Estimated code review effort

🎯 5 (Critical) | ⏱️ ~180+ minutes

Complexity drivers:

• Architectural overhaul: Request-based → payload-based system fundamentally reshapes control flow across 40+ contracts
• Type system changes: address → bytes32 for plugs/sockets throughout; uint40 → bytes32 for IDs; ExecuteParams → ExecutionParams
• New subsystems: Solana integration (Ed25519, Sha512, PDA), Borsh encoding, gas escrow, message switching—each adds significant density
• Interface churn: 15+ interfaces removed/replaced; event signatures altered across EventTopics
• Heterogeneous changes: Not a single refactor pattern but multiple concurrent redesigns (fees, authentication, cross-chain, precompiles)

High-risk areas requiring close attention:

• Payload ID decoding (IdUtils.sol): Bit-packing 256-bit structure with source/verification/pointer fields—off-by-one shifts cause silent failures
• Solana Ed25519 verification (Ed25519.sol): 80-round crypto loop with manual modular arithmetic; any constant or operation swap breaks signatures
• Gas escrow state transitions (GasEscrow.sol): Active→Released→Settled flow must prevent double-settlement and orphaned accounts
• Switchboard attestation thresholds (EVMxSwitchboard.sol, MessageSwitchboard.sol): Watcher count tracking and validity checks must be atomic; watcher role grants could corrupt counters if not guarded
• AppGatewayBase refactoring (AppGatewayBase.sol): Consolidated OverrideParams replaces 5 separate fields; any missing field in builder chain silently defaults
• Socket execution flow (Socket.sol): New ExecutionStatus tracking and fallback payload submission must not allow re-execution or orphaned payloads
• DigestUtils collision prevention (DigestUtils.sol): Variable-length encoding with explicit length prefixes—verify all call sites include payloadId, source, extraData in correct order
• Borsh encoding/decoding symmetry (BorshEncoder.sol, BorshDecoder.sol): Vector length prefixes and array packing must round-trip; mismatch between encode and decode causes Solana instruction failure

Possibly related PRs

• PR #215: Adds Solana integration layers (Ed25519, ForwarderSolana) and AppGatewayBase restructuring; this PR consolidates and expands those changes across the full watcher/switchboard/precompile stack.

Poem

🔄 From requests born to payloads bright,
💰 Gas flows where credits flickered light,
🔐 Ed25519 signs the Solana way,
🌉 Switchboards attest what plugs convey,
✨ One ID to encode them all—
A grand refactor answers the call! 🎆

Pre-merge checks and finishing touches

❌ Failed checks (1 inconclusive)

Check name	Status	Explanation	Resolution
Title check	❓ Inconclusive	The title 'Audit/9 5' is vague and generic, using only non-descriptive terms without conveying meaningful information about the changeset.	Revise the title to clearly describe the main change. This changeset restructures the entire fee/gas management architecture (from FeesManager/Credit to GasAccountManager/GasAccountToken), updates payload ID handling, and refactors switchboard/plugin systems. A title like 'Refactor fees architecture to gas-centric model with unified payload ID system' would be specific and actionable.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

✨ Finishing touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch audit/9-5

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