Skip to content
flexr

Security model

flexr specifications are Ruby programs. Rule actions, --eval, and generated actions can execute arbitrary Ruby with the permissions of the process that runs them.

Safe operating assumptions

Section titled “Safe operating assumptions”
  • Do not run an untrusted .flexr.rb file.
  • Treat generated Ruby as executable source and review it before deployment.
  • Use flexr check for diagnostics, not as a sandbox.
  • Keep build-time inputs and generator versions pinned in CI.

The hosted playground currently uses fixed fixtures and does not execute arbitrary Ruby. A future WASM worker must keep that boundary explicit, enforce resource limits, and never imply that parsing source is equivalent to sandboxing actions.