Commit Graph
54 Commits
Author SHA1 Message Date
jaap-jan b7325b78ca Record the platform flags that were only in conversation
ci / build and test (ubuntu) (push) Has been cancelled
ci / build (windows) (push) Has been cancelled
Development and testing are Windows-only, so anything unverified elsewhere
needs to be written down or it gets assumed to work. Several of these have
already cost time once: PostgreSQL 18 moving its data directory silently
gives a carried-over compose file an empty volume, and a loopback-bound
Tomcat beat Docker's 0.0.0.0 publish for `localhost`, making every Keycloak
realm 404 while the container looked healthy.

The largest entry is the Avalonia WebView on Linux, which remains the
biggest risk in the plan and is why the terminal sits behind ITerminalHost.

Also records two things this milestone deliberately left undone -- no rate
limiting on the enrollment and sync write paths until M2, and /me not
touching last_seen_at_utc -- so neither reads later as an oversight.
2026-07-28 16:08:04 +02:00
jaap-jan d2a2ed8a29 Specify the key statement encoding and key log chain (crypto.md 7.1, 7.2)
Section 7 always required "a canonical, length-prefixed encoding" for
signatures without ever specifying one. That gap had to be closed before
enrollment could exist: the client hashes the key statement and uses the
result as an OIDC nonce, so the provider signs over those exact bytes. Two
implementations disagreeing by one byte produce two nonces and an
enrollment nobody can verify -- and it only shows up against a real
provider, never in a local test.

JSON cannot be the hashed form. Property order, number formatting, Unicode
escaping and whitespace all vary between serialisers. So the statement is
transmitted as JSON and hashed as a fixed binary encoding, and the two are
independent by construction.

Three details are load-bearing rather than stylistic:

- The presence byte before each string is what makes the encoding
  injective. Without it an absent email and an empty one encode
  identically, and two different statements share a binding.
- Timestamps truncate to milliseconds. PostgreSQL stores microseconds, so
  a statement that has been through the database must still hash to what
  the client hashed. The same applies to the key log, where an entry that
  cannot reproduce its own hash after being read back makes the chain
  unverifiable.
- The key log entry hash deliberately excludes the database sequence. It
  is unknown until the insert runs, and order already follows the hash
  links -- so a renumbered or gapped sequence column cannot silently
  reorder history.

KeyStatementFields is separate from Contracts.KeyStatement on purpose: one
may gain JSON fields freely, the other cannot change without invalidating
every stored binding, and Crypto must not depend on the contract assembly.
KeyStatementDriftTests makes a field added to one and not the other a
build failure, because a wire field outside the binding is unauthenticated
data the server can change undetected.

54 new tests and two new golden vector sections. The vectors pin the
absent-versus-empty email case and confirm that an offset-bearing
sub-millisecond timestamp encodes identically to its truncated UTC form.
Only additions to vectors.json; nothing existing moved.
2026-07-28 16:06:11 +02:00
jaap-jan b15af836a3 Freeze DSH1 crypto specification and implement the core (M1)
docs/crypto.md is now the normative, frozen specification. This had to land before
anything else in M1: the server holds ciphertext and no keys, so it can never
re-encrypt, and a format change after users hold data is a coordinated client rewrite
with no rollback.

Specification:
- DSH1 envelope layout, canonical 64-byte AAD encoding, SealTo construction, key
  hierarchy, Argon2id profiles, fingerprints, and the change rules for each version field.
- AAD encoding is fixed-width binary rather than delimited string concatenation, so no
  field value can forge a field boundary. This supersedes the illustrative form sketched
  in ADR 0001, which now points here.
- UUIDs are RFC 4122 big-endian. Guid.ToByteArray() emits the first three groups
  little-endian and would have made our ciphertext unreadable by any other implementation
  of this spec, failing only at a cross-implementation boundary.

Verified rather than assumed:
- PrimitiveAvailabilityTests proves X25519, Ed25519, XChaCha20-Poly1305, Argon2id and
  HKDF-SHA512 all function on net10.0. NSec 26.4.0 targets net9.0 and is consumed by
  forward compatibility; this closes one of the two package questions the plan flagged.
- Argon2Profile exists because NSec's MemorySize is in KIBIBYTES, not bytes. Passing bytes
  gives either a 256 GiB allocation or a 256 KiB KDF that cracks instantly. The type takes
  mebibytes so the unit cannot be got wrong at a call site. Found by benchmarking: the
  first measurements were ~1000x too slow, which turned out to be 19 GiB of work.
- Parameters measured, not guessed: 256 MiB/t=4 is 323 ms on this machine; the table of
  candidates is in the spec.

Implementation and tests (83 total, up from 17):
- AadDescriptor, DshEnvelope, DshCrypto (Seal/Open/SealTo/OpenSealed/fingerprints).
- Decryption returns null rather than throwing: ciphertext comes from a server that is
  explicitly not trusted, so a failed tag is an expected outcome.
- Envelope readers reject unknown algorithms and any non-zero flag bit, so an envelope
  that is not fully understood fails closed.
- Executable form of the spec's substitution claims: a server cannot move ciphertext
  between resources, roll back a key generation or item version, repurpose a payload as
  metadata, or confuse the two constructions.
- Golden vectors in tests/fixtures/crypto/vectors.json guard the format. Mutation-checked:
  a one-byte schema version change trips four tests including the guard.

Two build-infrastructure bugs found and fixed along the way:
- .editorconfig forced camelCase on const and static readonly fields. PascalCase is the
  .NET convention for both; the config was wrong, not the code.
- The golden fixture was resolved with [CallerFilePath], which ContinuousIntegrationBuild
  rewrites to /_/... under deterministic source paths. It passed locally and would have
  failed only in CI. Now copied to the output directory and read from there.
2026-07-28 13:18:29 +02:00
jaap-jan ce43f397a6 Add ADRs 0001-0006 and README (M0)
Records the decisions the milestone plan already made, with their costs stated rather
than only their benefits:

- 0001 e2ee-trust-model: key hierarchy, the AAD-to-row binding that stops the server
  moving ciphertext between rows, and the four-layer public-key trust story. States
  plainly that revocation is not retroactive, that Connect cannot be a security
  boundary, and that the IdP becomes a key-distribution trust root.
- 0002 minimal-apis: feature modules with explicit registration; capability negotiation
  instead of Asp.Versioning, since client and server upgrade independently when
  self-hosted.
- 0003 sync-protocol: single write path, revision cursors, and the bigserial
  pre-commit sequence gap that silently corrupts sync — plus the per-vault advisory
  lock that fixes it and the test that must prove it.
- 0004 relay-authorization: relay forwards bytes rather than terminating SSH, so
  zero-knowledge survives; server-resolved target IPs in the ticket to defeat DNS
  rebinding; why host addresses must be plaintext when relay is enabled.
- 0005 no-application-layer: why the usual Application/mediator layer earns nothing
  here, with the trigger that would make us revisit it.
- 0006 observability-stack: OTel plus built-in ILogger; liveness excludes dependencies
  so a database blip cannot restart the container and kill live SSH sessions.

Also adds a README covering layout, build, enforced conventions and milestones.
2026-07-28 12:28:44 +02:00