Review follow-ups: IPv6 peers, constant-time admin key, magnet hash validation#6
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…alidation Three lower-priority findings from the 2026-06-13 review: - internal/client: unpackPeers only handled the 6-byte IPv4 compact form and the tracker response never decoded peers6, so IPv6 swarms were silently dropped. Decode the BEP 7 peers6 key and parse both forms (4- and 16-byte addresses) via a length-parameterized unpacker. Adds an IPv6 test. - internal/tracker: registry POST/DELETE admin-key check used a plain string compare (timing side-channel); switch to subtle.ConstantTimeCompare for parity with the HMAC announce path. - cmd/wl: 'wl get' discarded the hex.DecodeString error for the v1 info hash, handing a truncated hash to the downloader. Reject a malformed value at the boundary (empty v1 hash for v2-only magnets is still fine). The wire.go payload-cap 'comment mismatch' from the review was a false positive: 2<<20 is exactly 2 MiB, matching the comment.
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Jun 21, 2026
Review follow-ups: IPv6 peers, constant-time admin key, magnet hash validation
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The lower-priority findings from the 2026-06-13 review (follow-up to #5).
Changes
IPv6 peer support —
internal/client/tracker.gounpackPeersonly handled the 6-byte IPv4 compact form and the tracker response struct never decoded thepeers6key, so IPv6 swarms were silently dropped. Now decodes BEP 7peers6and parses both the 6-byte (IPv4) and 18-byte (IPv6) compact forms through a length-parameterized unpacker. IPv6 test added.Constant-time admin-key compare —
internal/tracker/registry.goThe registry POST/DELETE
X-Weightless-Keycheck used a plain!=string compare (timing side-channel). Switched tosubtle.ConstantTimeCompare, matching the HMAC announce path.Magnet v1-hash validation —
cmd/wl/main.gowl getdiscarded thehex.DecodeStringerror for the v1 info hash, handing a truncated/garbage hash to the downloader. Now rejects a malformed value at the boundary; an empty v1 hash (v2-only magnet) is still accepted.Dropped (false positive)
The review's
wire.go"payload cap comment mismatch" —2<<20is exactly 2 MiB, which matches the "2MB max payload" comment. No change.Verification
go build ./...,go vet ./...,gofmtcleango test ./...— all pass, including the newTestUnpackPeersIPv6🤖 Generated with Claude Code