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fix(net): keep guest TLS aborts from crashing Bun hosts - #154
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When a guest closes an intercepted TLS flow while the host still has ciphertext pending (e.g. after rejecting the MITM certificate), the pending guest write fails with "guest closed" and the wrapped GuestTlsStream emits 'error'. Node forwards it to the TLS socket; Bun does not, so it became an uncaught exception that terminated the host process and every VM in it. Listen for the stream error and destroy only that flow's TLS socket. Adds a VM-free regression test that reproduces the crash on Bun.
guillemborrell
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October 5, 2026 17:46
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Follow-up to #152.
When a guest closes an intercepted TLS flow while the host still has ciphertext pending, the host process crashes on Bun. Rejecting the MITM certificate is enough to trigger it: custom CA bundles,
certifi, pinning, or any HTTPS in a VM without the MITM CA mounted (vfs: null).The pending guest write in
GuestTlsStreamfails with "guest closed", and the wrapped stream emitserror. That stream has noerrorlistener:TLSSocket, so nothing breaks.The
endNT → shutdown → _write → waitForFlowResumestack shows the trigger is the final write fromtlsSocket.end()afterhandleTcpClose.Fix
Add an
errorlistener on the guest stream that destroys only that flow's TLS socket, and emit a debug message for errors other than guest-closed. This is a no-op on Node.Test
tls-mitm-sni.test.tsgains a VM-free case:handleTcpClose({ destroy: false })while the host's writes are flow-control paused.GuestClosedErroruncaught)On a real VM (macOS arm64, krun): an HTTPS attempt in a deny-all VM, and a guest
curl --cacert <unrelated CA>in an allowlist VM, each crashed a Bun host before this change. After it, the host survives and keeps serving, on both runtimes.node --test test/*.test.ts: 643 pass, 13 skipped, 4 fail. The four failures (clock-sync, vfs-many-mounts, vfs chmod, exec deleteFile) also fail onmainon this machine.