fix: guard RemoteAddr parsing against out-of-bounds slice panic#2463
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iliaal wants to merge 1 commit into
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fix: guard RemoteAddr parsing against out-of-bounds slice panic#2463iliaal wants to merge 1 commit into
iliaal wants to merge 1 commit into
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addKnownVariablesToServer stripped IPv6 brackets with an unchecked slice (ip[1:len(ip)-1]). A malformed RemoteAddr such as "[" or "[:9000" produced a 1-byte ip and panicked. This runs inside the go_register_server_variables cgo callback, where a Go panic cannot unwind through the C frame and aborts the whole process rather than failing a single request. Extract splitRemoteAddr, which parses via net.SplitHostPort and falls back to a bounds-safe lenient split that only strips brackets when both are present. Behavior for well-formed addresses is unchanged.
dunglas
approved these changes
Jun 4, 2026
henderkes
approved these changes
Jun 4, 2026
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addKnownVariablesToServerstripped IPv6 brackets with an unchecked slice, so a malformedRemoteAddrlike"["or"[:9000"panicked. This runs in thego_register_server_variablescgo callback, where a panic can't cross the C frame and crashes the whole process. Not reachable behind stock Caddy; reachable for library callers and real-IP rewrites.Fix: parse via
net.SplitHostPortwith a bounds-safe fallback.TestSplitRemoteAddrcovers the crashing inputs; well-formed addresses are unchanged.