tools(skills): add encrypted-dns-skill (ednsdiag CLI + agent skill)

2026-08-13 12:52:20 +08:00
parent 95ec2350af
commit c0cf82d4af
24 changed files with 2086 additions and 0 deletions
@@ -0,0 +1,58 @@
+# Security and privacy requirements
+
+Read this file before changing transports, bootstrap behavior, endpoint
+validation, fallback, or result claims.
+
+## Non-negotiable rules
+
+1. Never silently downgrade to plaintext DNS.
+2. Validate certificates and authentication domain names. DoT follows the
+   strict privacy profile in [RFC 8310](https://www.rfc-editor.org/rfc/rfc8310.html).
+3. Treat certificate, hostname, SNI, and negotiated ALPN mismatches as hard
+   failures, not fallback opportunities.
+4. Bound response sizes, per-attempt timeouts, total time, redirects, and the
+   number of attempts.
+5. Do not expose an unrestricted endpoint parameter to an Agent. Built-in
+   providers are allowlisted; private or custom endpoints require explicit
+   user intent and policy approval.
+6. Do not connect to addresses returned in DNS answers.
+7. Do not enable AXFR, IXFR, or ANY queries.
+8. Do not persist full query names or client identifiers by default.
+
+## DoT ALPN policy
+
+The client advertises the `dot` ALPN identifier. RFC 7858 and RFC 8310 do not
+require a DoT server on its dedicated port to select an ALPN protocol, so an
+empty negotiated ALPN is permitted and reported as empty. If a server selects
+a non-empty protocol other than `dot`, abort before sending the DNS query.
+
+## Bootstrap transparency
+
+Connecting to a resolver hostname may require an initial DNS lookup. Report
+whether the endpoint was reached using a configured bootstrap address, the
+system resolver, or an already-known IP. Do not claim that a query avoided the
+system resolver when bootstrap used it.
+
+## DNS status and fallback
+
+An HTTP, TLS, or QUIC exchange can succeed while DNS returns `NXDOMAIN`,
+`SERVFAIL`, or `REFUSED`. Those are DNS outcomes and must not be converted into
+transport errors. Cross-provider or cross-protocol fallback is permitted only
+for explicitly classified transport failures and must be disclosed.
+
+## DNSSEC language
+
+The AD bit means the selected recursive resolver reports authenticated data.
+It is not proof that this client validated the DNSSEC chain. Use separate
+fields for resolver-reported and locally validated DNSSEC state.
+
+## Privacy language
+
+Encrypted transport protects the path between the client and the selected
+resolver. The resolver can still observe the query. Provider policy, logging,
+filtering, ECS behavior, and jurisdiction remain relevant. See
+[RFC 8932](https://www.rfc-editor.org/rfc/rfc8932.html).
+
+ODoH and Anonymized DNSCrypt add relay models but do not justify claims of
+absolute anonymity. Their proxy, relay, and target roles must be reported
+separately.