allowlist

Overview ¶

Package allowlist copies caller-supplied text out of a fixed alphabet.

It exists for the places where a validated string is about to become part of something that executes — a SQL identifier, an argv entry. Checking the input and then using the input leaves the executed bytes owned by whoever supplied them; copying through an alphabet makes them bytes the program spelled out, and turns "I validated this" into a property of the value rather than of the control flow that produced it.