synapse-relay

The server employs several security measures including CORS with an explicit whitelist, rate limiting on HTTP endpoints, and input validation using Zod for MCP tools. Critically, the InterLock Tumbler (`src/interlock/tumbler.ts`) enforces whitelisting of allowed peers and signal types for UDP messages, along with freshness checks, significantly enhancing the security of the InterLock mesh communication. Database interactions utilize prepared statements, mitigating SQL injection risks. A notable architectural choice is the use of 'localhost' for all outgoing UDP messages to specified peer ports, implying that all InterLock 'peers' are expected to run on the same machine as synapse-relay, differentiated by port. While this limits true distributed network mesh capabilities, it also prevents sending UDP packets to arbitrary remote IPs, which can be seen as a security feature in a single-host inter-process communication context. Overall, the server demonstrates a good commitment to security best practices for its intended operational scope.