jaap-jan
e3fd3e1728
Completes the client half of SSH keys: they sync alongside hosts, appear in their own list, and can be selected to authenticate a connection instead of typing a password. The reconciler and the repository were Host-typed throughout, so the choice was to generalise them or to keep a second copy per item type. Generalised, because ItemReconciler's whole premise is that the pull and the push paths must answer the same collision the same way — two copies would drift the first time one of them was fixed. What is genuinely per-type now arrives through IItemKind<TSecret>: the cipher, the merge, the plaintext columns, and the noun to use when telling a person what happened to their item. Generic where the server's IItemKind is not, and for the reason that reverses there — the client needs the concrete type, because it merges field by field. The pull filter is derived from the same registry that builds the reconcilers. That is the specific failure being designed out: an item type that encrypts, merges and lists perfectly and is never once requested from the server, so it works on the machine that made it and exists nowhere else. No client cache migration. The item table's primary key and the outbox's unique index already carry the entity type, and AadResourceTypes already mapped SshKey — so a host and a key may share an id and never see each other's rows, which SshKeySyncTests now arranges deliberately. A key hands the server nothing in plaintext. There is a public_key_fingerprint column and it would be accepted; leaving it null is deliberate. A fingerprint is not secret but it is a stable identifier for a key pair, so filling it would let an operator tell which of their users hold the same key and correlate one across vaults, for a column nothing reads. The design allows itself one plaintext concession — the relay address, which the relay cannot work without — and this is not that. A key is chosen per connection rather than bound to a host, which works the way ssh -i does. Binding one needs a field on HostSecret and therefore a payload schema bump, which makes every host written afterwards read-only on an older build; worth doing deliberately rather than as a side effect of adding keys. Three things this found, all of them by being falsified rather than by review: - Making the reconciler generic silently turned a record comparison into reference equality, because == on a type parameter is not value equality. The effect would have been a conflict recorded on every pass for an unacknowledged create that had in fact landed. Sabotaging the fix left all 73 tests passing — nothing covered that branch — so ConflictMatrixTests now has AnUnacknowledgedCreateThatDidLand_IsDroppedQuietly, which fails without it. - A test asserting that a blank passphrase reaches SSH.NET as null was vacuous: it exercised the editor, not the credential path, and passed with the guard deleted. Resolved by making SshKeySecret.Passphrase normalise an empty string to null, so there is one spelling of one state — which also keeps two clients from producing different payload bytes for an identical key. That exposed a wider gap: SshKeySecret, its codec and its merge had no direct unit tests at all. They have 25 now. - The reason first given for that normalisation was false. It claimed SSH.NET rejects a passphrase supplied for an unprotected key; measured against a real sshd it ignores it and authenticates anyway. Corrected everywhere it was stated and recorded in docs/platform-flags.md. The same test file also closes a real hole: SshPrivateKeyCredential had never been exercised against a server, because the existing key test builds SSH.NET's auth method directly and bypasses the path a vault-held key actually takes. Only one editor may be open at a time. Both sit in the same 340-pixel column as Auto rows and their heights together exceed it at the window's minimum size, so two open editors put the lower one's Save and Cancel past the bottom edge — the same failure this window already shipped once with the setup screens. Expressed as a state rule because that is the only form of it this repository can check: nothing here loads a .axaml. The refusal keeps what was typed, since in the key editor that is a pasted private key the user may have nowhere else. The end-to-end slice now carries a key as well as a host, so both item types go through the real API, the real PostgreSQL and the real crypto in one pass — the three hand-kept mappings between enums that do not line up are the reason that is worth doing rather than trusting the unit suites. 735 tests green, including the container-backed SSH and end-to-end suites. Zero warnings, dotnet format clean.
11 KiB
DodoSSH
A self-hosted, team-oriented SSH client with an end-to-end encrypted vault.
Manage hosts, credentials and keys in a desktop app; sync them across your devices and share them with teammates through a server you run yourself. The server stores ciphertext and never holds a key — the operator cannot read the credentials it stores.
Status: early development. See the milestone plan for what exists today.
Why
Teams either scatter SSH credentials across individual ~/.ssh directories with no sharing
story, or pay per-seat for a hosted product that holds their infrastructure credentials.
DodoSSH keeps the convenience of a synced, shareable vault while remaining self-hostable and
zero-knowledge.
Architecture
| Component | Choice |
|---|---|
| Backend | ASP.NET Core on .NET 10, PostgreSQL + EF Core |
| Client | Avalonia (C#) for Windows/Linux/macOS; terminal pane is a WebView running xterm.js |
| Auth | OIDC, provider-agnostic (Entra ID, Keycloak, Auth0, Authentik) |
| Vault | End-to-end encrypted; X25519 + Ed25519 + XChaCha20-Poly1305, Argon2id unlock |
| Connections | Client-direct SSH by default, with an optional raw-TCP server relay |
Three consequences worth knowing before you read further:
- Revocation is not retroactive. A removed member keeps what they already downloaded. The real remediation is rotating the SSH credential, so offboarding is built around a rotation checklist rather than a button that implies more than it delivers.
- No session recording in relay mode. The relay forwards SSH ciphertext, so it cannot see commands. That is the cost of the relay not being able to read your traffic.
- Locking the vault does not close your shells. Lock closes the vault and zeroes every key it held; a session that authenticated before it keeps running, because the remote host never consulted the vault and the credential was already spent. That is deliberate — you lock when you walk away from the machine, which is exactly when a long upgrade or transfer is most likely to be in flight, and an idle auto-lock that killed it would be worse than the exposure it removed. The honest reading is that locked describes the vault and not this machine's access to your hosts. The unlock screen therefore shows how many shells are still connected, and quitting DodoSSH is what ends them.
The reasoning behind each major decision is recorded in docs/adr/, starting with
the E2EE trust model.
Repository layout
src/
DodoSSH.Contracts DTOs shared with the client — the real API contract
DodoSSH.Crypto DSH1 envelope, AAD derivation, the key hierarchy
DodoSSH.Domain entities and invariants, no EF
DodoSSH.Infrastructure DbContext, configurations, migrations
DodoSSH.Api the server
DodoSSH.Client.Auth OIDC code+PKCE on a loopback redirect, and the key binding
DodoSSH.Client.Api the typed server client, and client-side enrollment
DodoSSH.Client.Domain the decrypted item model and the three-way merge — no I/O at all
DodoSSH.Client.Storage the local cache: ciphertext mirror, outbox, offline unlock material
DodoSSH.Client.Sync the pull/apply/push loop and the conflict policy
DodoSSH.Client.Session where a profile lives, unlocking it, and getting one in the first place
DodoSSH.Client.Ssh connections, PTY shells, host key trust
DodoSSH.Client.Terminal the loopback data plane and credit-based flow control
DodoSSH.Client.App Avalonia; the only project that knows about a UI toolkit
tests/ one test project per source project
docs/adr/ architecture decision records
Everything under src/DodoSSH.Client.* except App is deliberately free of Avalonia. That is the
seam that lets the SSH layer, the terminal's flow control and the OIDC flow be tested without a UI
toolkit or a browser engine — which is most of why they are testable at all.
Building
Requires the .NET SDK pinned in global.json (10.0.x).
dotnet build DodoSSH.slnx
dotnet test DodoSSH.slnx
The tests need a Docker daemon. Everything that touches the database, the identity provider or an SSH server uses Testcontainers rather than a stub or a shared instance, so there is nothing to start first and nothing to clean up after — but with no daemon those suites fail rather than skip.
Running it
Four commands, in order. The first two are once per machine.
1. The development dependencies — PostgreSQL and Keycloak, with the dodossh realm imported:
docker compose -f deploy/docker-compose.dev.yml up -d
2. The schema. The API never migrates anything: it fails readiness while a migration is pending, and
says which one. dotnet-ef is pinned in .config/dotnet-tools.json, so run dotnet tool restore first if
you have not:
dotnet ef database update --project src/DodoSSH.Infrastructure
With nothing else configured this targets the compose stack above. Set DODOSSH_DESIGN_CONNECTION to point
it at another database.
3. The server:
dotnet run --project src/DodoSSH.Api
It listens on http://localhost:5233, serving /healthz/live, /healthz/ready and — in
Development — /openapi/v1.json.
4. The desktop client:
dotnet run --project src/DodoSSH.Client.App
In the app, enter http://localhost:5233 as the server. Your browser opens for sign-in — the realm ships
alice / alice — then choose a vault passphrase and write down the recovery code, which cannot be
skipped and cannot be recovered from the server. You can then add a host and open a shell on it. Keycloak's
admin console is at http://localhost:18080 (admin / admin).
You can also add an SSH key, which is stored in the vault like a host and synced the same way: paste the private key, tick Use key next to Connect, and the selected key authenticates instead of a password.
Three of M1's known gaps are visible immediately, so they are worth expecting rather than diagnosing: password authentication asks for the password every time, because credentials are not a synced entity type yet (keys are — passwords are not); a key is chosen per connection rather than remembered per host, because binding one to a host needs a new field on the host payload and so a schema version bump; and unlock asks for the passphrase on every launch, because no device key is registered. Host key trust also lasts one session, because known hosts do not live in the vault yet.
End-to-end verification
One suite runs against a real server rather than a stub. It needs a Docker daemon and nothing else, so it is part of the ordinary test run:
dotnet test tests/DodoSSH.SystemTests
It brings up PostgreSQL, Keycloak and an OpenSSH server in containers, applies the committed migrations,
starts the API as a child process out of its own build output, and then drives the real client: sign in
through Keycloak, enroll, unlock, create a host, sync it, read it back on a second simulated machine,
unlock again with no network, and open a shell on the sshd. Roughly 25 seconds once the images are
pulled.
What makes it worth its weight is that it consumes the artefacts that ship — the realm file from
deploy/keycloak, the EF migrations, the API's own appsettings — rather than a fixture written to match
them. On its first run it found a loopback redirect URI the realm registered in a form Keycloak rejects,
and a JSON configuration gap that made the whole sync surface unreachable from the real client while every
other test passed. Both are the same class of bug: two sides of a stub agreeing with each other about
something the specification never said.
The one value it cannot take from a committed file is Oidc:Authority, since the container's port is
assigned at start. Everything that authority points at is still the real realm.
Development and testing are currently Windows-only. Anything known or suspected to differ on
Linux and macOS is tracked in docs/platform-flags.md, along with the
deployment gotchas that have already cost time once. Read it before assuming something works
off-Windows.
Conventions the build enforces
- Warnings are errors.
dotnet format --verify-no-changesgates CI. - Package versions are centralised in
Directory.Packages.props;packages.lock.jsonis committed and CI restores in locked mode. BannedSymbols.txtbansDateTime.UtcNow(useTimeProvider),Guid.NewGuid(useCreateVersion7), sync-over-async, MD5/SHA1 and PBKDF2.- Public members of
DodoSSH.Contractsmust be declared inPublicAPI.Unshipped.txt, so a contract change is a build error rather than a client-side surprise.
Milestones
-
M0 — foundation. Repo structure, build conventions, CI, ADRs. Done.
-
M1 — vertical slice. OIDC login → enroll → create a host → open a shell. Server done: the DSH1 crypto core, the data model, sync push/pull for hosts,
/me, and enrollment with the identity-provider key binding. Client done: the key hierarchy, the OIDC flow with the key binding, SSH connections with host key trust, the terminal data plane, the encrypted local cache with the sync client — offline unlock, an outbox and a field-level three-way merge, conflict matrix green — and an Avalonia shell that is vault-backed: server URL → browser sign-in → enroll → unlock → host list → terminal. The shell's state machine is covered by tests against an in-memory server, so the states that matter most (the recovery code that cannot be skipped, the unlock that needs no network) are checked rather than remembered.Its layout is not covered by anything, and that gap has already cost a shipped defect: the setup and unlock screens were layered over the terminal's WebView, which on Windows is a native child window that cannot be covered, so they rendered sliced with their buttons unclickable. No test in this repository loads a
.axamlfile, and a headless one could not have caught this — there is no native window in headless, so it would have rendered perfectly and confirmed the wrong belief. Screens get looked at, or they are unverified. Verified end to end:tests/DodoSSH.SystemTestsdrives the whole slice against a real Keycloak, a real API, a real PostgreSQL and a realsshd— sign-in, the identity-provider key binding, enrollment, offline unlock, a host through the vault to a second machine, and an interactive shell. See End-to-end verification.Known gaps in the client, stated rather than implied by the interface: credentials are not a synced entity type yet, so password authentication still asks for the password each time — SSH keys are synced, and are the way to connect without typing anything; a key is picked per connection rather than bound to a host, which needs a field on the host payload and therefore a schema version bump; known host keys live in memory for one session instead of in the vault; and no device key is registered, so the passphrase is needed on every launch until the OS keystore is wired.
-
M2 — full personal vault, robust sync, relay.
-
M3 — teams, sharing, ACLs.
-
M4 — hardening and ops, packaging, self-hosting guide.
-
M5 — multi-provider OIDC, key rotation, per-item content keys.
Licence
MIT.