wweir b688b93fbc fix(sower): refuse a proxy dial that resolves into this client's own listener ...

One request to a name whose A record is the client's own serve address
became a self-sustaining chain: the proxy forwarded it into the tunnel, the
relay resolved the name back to the client and dialed the client's own
listener, which forwarded it again. Measured on r6c: 601 connections and a
relay host that ran out of memory.

A proxy dial must never re-enter a listener this client forwards proxy
traffic on. Router.DialProxyOnly now refuses such a target: the listener set
is the HTTP/HTTPS proxy addresses on every DNS listen address plus SOCKS5,
resolution is skipped for ports this client does not serve, and the answer is
cached for a minute so a proxied dial does not pay a DNS round trip per
connection. Refusals surface as ErrSelfProxyTarget - HTTP 403, SOCKS5 0x02 -
and a resolution failure is not treated as evidence of self-targeting.

Plan, rejected alternatives and the evidence trail:
docs/plans/2026-10-12-self-proxy-target-guard.md

2026-10-12 19:30:56 +08:00

..

sower

fix(sower): refuse a proxy dial that resolves into this client's own listener

2026-10-12 19:30:56 +08:00

sowerd

fix(sowerd): keep the SIGUSR1 heap dump off the Windows build

2026-10-12 19:13:36 +08:00