Fixing Concurrency Bugs in AWS SSM Plugin Enables VS Code Remote SSH
2025-02-12
A recent Stanford graduate at Formal, while troubleshooting a customer issue with Visual Studio Code's Remote SSH connection to AWS EC2 instances for machine learning, unexpectedly uncovered and fixed several concurrency bugs in AWS's SSM reference library. The problem stemmed from insufficient TCP/IP port forwarding support in the Formal Connector, preventing VS Code from properly initializing the remote development environment. The fix involved deep dives into SSH and SSM protocols, ultimately resolving data races and sequence number issues by modifying the AWS Session Manager plugin. This now allows secure VS Code Remote SSH connections through the Formal Connector.