dosh/docs/AUDIT_PACKET.md

Dosh Native v1 Audit Packet

This is the handoff checklist for an external security review.

Scope

Review the security properties of Dosh native v1:

• Native UDP authentication and key exchange
• Host key trust and known-host mismatch behavior
• Authorized key parsing and policy enforcement
• Transport encryption, replay protection, rekeying, resume, and stale packet handling
• Attach ticket sealing/opening
• TCP forwarding and agent forwarding authorization boundaries
• Parser robustness for untrusted wire/config data

Primary files:

• src/native.rs
• src/protocol.rs
• src/auth.rs
• src/ssh_agent.rs
• src/bin/dosh-client.rs
• src/bin/dosh-server.rs
• src/config.rs
• tests/parser_robustness.rs
• tests/protocol_auth.rs
• tests/hostile_network.rs
• tests/integration_smoke.rs
• fuzz/fuzz_targets/*

Primary docs:

• docs/NATIVE_V1_SPEC.md
• docs/THREAT_MODEL.md
• docs/PROTOCOL_VERSIONING.md
• docs/PUBLIC_READINESS.md
• docs/RELEASE_EVIDENCE_2026-06-20.md

Required Reviewer Questions

1. Is the native handshake transcript complete enough to bind client/server keys, requested session, mode, env, and forwarding permissions?
2. Are host-key trust transitions fail-closed, especially unknown vs mismatch vs explicit TOFU?
3. Are authorized-key options parsed conservatively enough, and are unsupported options rejected safely?
4. Can replayed, reordered, delayed, stale, or cross-epoch packets affect terminal input or forwarded streams more than once?
5. Does key rotation preserve confidentiality without creating split-brain epoch states?
6. Do attach tickets create any bearer-token replay or privilege-extension issue?
7. Can UDP endpoint migration be abused for hijack or reflection?
8. Are local/remote/dynamic TCP forwarding and agent forwarding gated correctly by client opt-in, server config, and authorized-key options?
9. Are parser and packet-size limits sufficient against malicious inputs?
10. Are there any unsafe assumptions in process/session persistence or holder adoption?

Current Local Evidence

As of 2026-06-20:

• cargo test: 153 passed, 1 ignored
• make soak-local: passed 30-minute sleep/roaming soak
• make fuzz-smoke: passed all configured fuzz targets for 20s each
• make bench-docker-mosh: passed SSH, ControlMaster, native, cached, and Mosh comparison gates

Explicit Non-Claims Before Audit

• No claim of generic SSH protocol replacement.
• No claim of full Mosh compatibility.
• No claim that native v1 is externally audited.
• No claim that Windows server support is production-ready.