This is a submission for DEV's Summer Bug Smash: Clear the Lineup powered by Sentry.
Project Overview
py-libp2p is the Python implementation of libp2p — the peer-to-peer networking stack that underpins IPFS, Filecoin, and Ethereum-class nodes. I've been working on its WebRTC-Direct transport, which lets two peers connect without a certificate authority: the peer's multiaddr carries a hash of its TLS cert, and the DTLS handshake is verified against it.
Before that encrypted transport exists, the two sides have to swap SDP offer/answer blobs. Until the STUN-based listener lands (#1352), py-libp2p ships a minimal dev harness for this: a tiny hand-rolled HTTP server (no aiohttp dependency) that accepts an SDP offer over POST /sdp and hands the body to an offer handler. This post is about a memory-amplification DoS I found and fixed in that harness.
Bug Fix or Performance Improvement
