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The WebView sat inside the Hosts grid, so navigating to Files or the keychain hid every open terminal and the strip that named them. A connection you had opened was invisible from four of the five screens. The window now has two surfaces rather than one: a nav rail that says which page you are on, and a terminal strip that is always there and switches the whole content area to a shell. Screen keeps meaning "which page" and never becomes a sixth kind of page, which is why this is two properties instead of one enum with a terminal member in it. Every screen lives inside one wrapper panel that collapses when a terminal is showing. That is not tidiness — the WebView hosts a Win32 child window that composites above everything Avalonia draws, so a screen left visible over its rectangle is a screen sliced in half, and this window has shipped that defect once already. One decision point, IsTerminalShowing, and a nested panel rather than five compound bindings nobody would remember to extend. The focus choreography is the part no test in this repo can see. Every reveal path now focuses in the same turn the WebView appeared, so all three of them post at DispatcherPriority.Loaded and let the native control re-push its bounds first. Going the other way had a real bug: the screen-changed branch called a bare Focus() where it had to release the keyboard from the native child, so switching from a terminal to Files silently ate the first keystrokes. Rare before this commit and the primary gesture after it. The tab strip grew a cross inside each tab, a plus that opens the quick-connect palette, and middle-click close. Nested buttons are correct here: Avalonia handles a left press on the cross and deliberately does not handle other buttons, which is exactly what lets middle-click bubble up from the cross as well as the tab. The test is PointerUpdateKind rather than IsMiddleButtonPressed, because the latter reports button state and is also true for a left press made while the middle button happens to be held. The handler is on the tab and not the strip, so the background closes nothing by construction. Plus opens the palette rather than a flyout, since a menu dropping into the WebView's rectangle may or may not composite above a child HWND and this repo does not make rendering claims it has not photographed. Everything a user reads now says keychain. The wire, the database and the cryptographic spec still say vault, deliberately: renaming those is a migration and a protocol change for a word. That split is written down rather than left to be rediscovered as an inconsistency. Four things that were squeezed into the keychain's category rail, or into nothing at all, now have screens. Pinned host keys get one, with fingerprints never truncated and a filter that matches them, because comparing what you have against what the operator published is the whole workflow; the approved date is read out of the item's UUIDv7 rather than added as a column, and says so, since it means first approval and not last use. Keys can be generated in the client, which needed the openssh-key-v1 container written by hand — there is no BCL or NSec helper, and the PKCS#8 route is unverified in the SSH library this uses. The armour carries no passphrase: encrypting it needs bcrypt_pbkdf, which is Blowfish with a swizzle, in a project whose crypto is otherwise entirely libsodium, for a protection the key's own remarks argue is redundant inside a vault. Generation fills the existing editor and stops, so SAVE stays the one thing that writes. ~/.ssh/config can be imported behind a preview that is ticked per row and writes nothing until the button; IdentityFile records the path and imports the key material only on an explicit opt-in, because reading somebody's private key into a vault is precisely the act this product exists to make deliberate. Match blocks and ProxyJump are reported rather than obeyed — one cannot be evaluated statically and the other has nothing behind it to route with, and a preview that implied otherwise would be worse than one that admits it. Files can be dragged in all four directions that are honestly available. Remote to Explorer does not ship and is not pretended to: the shell wants the bytes during the drop, which needs a virtual file and a native COM data object, outside what Avalonia offers. Note for the next person that Avalonia 12 replaced the drag model outright — DataObject and DataFormats are no-op stubs and IDataObject is not in the reference assembly, so every tutorial written for 11 does not compile here. Hosts can be grouped, flat and never nested. A parent id merged as a scalar lets two offline clients each re-parent A under B and B under A, producing a cycle inside an encrypted payload that no server can police and every reader would have to detect for ever. Membership lives in that payload rather than in the one plaintext concession ADR 0001 allows, whose test is that the relay cannot function without it — nothing on the server reads a group, so what plaintext would hand over is a clustering of the estate for nothing. The plaintext column reserved for it is dropped, provably always null, and the server now refuses a client that sends one; it was never populated, was copied on apply, and was not cleared on delete, so a group id would have outlived the host it described. Snippets insert through xterm rather than through the pump, because xterm is the only thing that knows whether the remote has bracketed paste on, and that is what makes a shell treat embedded newlines as text instead of as execute. The host process moves opaque bytes and never parses output, so it would have to guess, and guessing wrong runs every line. Running is off by default and the copy says the text goes into whatever is there — the terminal has no notion of being at a prompt, and may be in vi or at a password prompt with echo off, so the Enter the user presses themselves is the entire safety property. Connections and keychain changes are recorded as synced encrypted items, which is what makes them auditable by a team later and costs the server knowledge of connection rate and timing from row counts alone. ADR 0001 already concedes it cannot hide that class of metadata; the trade is now written into it rather than left implicit. A connection entry is written once, at close, which is what makes a synced log tractable: nothing to merge, one outbox row, no chance of colliding with itself. Live sessions come from memory, not from the log. The write is void by contract and posts to a bounded channel, because putting an encrypt-and-write on the teardown path of every session is how closing the application comes to take four seconds. A ticket opened before a lock still closes afterwards, since a shell outlives the vault. The activity log hooks the one generic repository every kind writes through, so it cannot miss a caller — which is also why the log kinds themselves declare they are not audited, or the first entry would write an entry about writing an entry. It records the names of the fields that changed and never their values; a log with an old password in it would be a plaintext credential store with no vault around it. Retention is 90 days or 5,000 entries, whichever bites first, pruned on the sync loop rather than on a second timer. That log traffic then broke the status line, which is worth recording because the fix is a shape and not a patch: background sync counted its own log rows as pushed items, so the quiet rule stopped being quiet and every action's message was overwritten a second later by a sync report. The report now separates log rows from user items and the rule reads the latter. S3 buckets appear as a remote in the file browser, behind the same interface an SFTP session implements, so the queue and both panes did not have to learn what they are talking to. Uploads go through a pipe, because the queue wants to write and the SDK wants to read; memory is then bounded by the part size instead of buffering a file to disk twice. Finally, the Windows device key store moved out of the session project, which was the one thing keeping it from being portable — everything else in it is platform-neutral, and a Windows CNG dependency in the middle of the vault code meant a second head could not reference it without dragging Windows along. The seam that made the move free was already there. docs/android-port.md is the audit behind that: what ports, what does not, in order of cost, the four decisions taken, and an inventory of every screen and state the interface has to carry, written so a design can be made from it directly. dotnet build, dotnet test and dotnet format --verify-no-changes are all clean: 1240 tests at zero warnings, including the end-to-end suite against real containers. The manual checks that headless Avalonia cannot make — the drag from Explorer, a generated key against a real host, twelve tabs at the minimum window width — are listed in docs/manual-checks.md and are still outstanding.
120 lines
7.6 KiB
Markdown
120 lines
7.6 KiB
Markdown
# ADR 0001 — End-to-end encrypted vault and its trust model
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- Status: accepted
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- Date: 2026-07-28
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## Context
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DodoSSH stores SSH credentials — passwords, private keys, key passphrases — on a server so
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they can sync across a user's devices and be shared with teammates. Authentication is OIDC
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against a provider the operator chooses.
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The product is self-hosted. Its buyers are teams who currently refuse to put infrastructure
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credentials into a SaaS vault. "Trust us with your production keys" is exactly the promise
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we cannot make.
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## Decision
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**The vault is end-to-end encrypted. The server stores ciphertext and never holds a key.**
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1. **A vault passphrase separate from OIDC.** OIDC authenticates but yields no secret we can
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derive a key from, and SSO compromise must not equal vault compromise. The passphrase
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goes through Argon2id (m=256 MiB, t=4, p=1) to a master key that never leaves RAM.
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2. **A per-user keypair, wrapped many ways.** The master key wraps a ~200-byte
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`UserSecretBundle` (X25519 + Ed25519 private keys). The *same* bundle is stored under
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several independent wraps: passphrase, one per enrolled device, recovery code, and
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optionally escrow. A passphrase change therefore re-wraps 200 bytes and updates one row —
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no re-encryption of vault data and no coordination with other members.
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3. **Vault keys, then per-item data keys.** A vault key is sealed to each member's X25519
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key; each item has its own data key wrapped under the vault key. Rotating a vault key
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re-wraps N × 32-byte data keys and never touches content blobs.
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4. **AAD bound to row identity.** Every ciphertext's AAD is recomputed from the row's
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plaintext columns rather than stored, over `purpose`, `resourceType`, `resourceId`,
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`keyId`, `keyGeneration`, `itemVersion` and `schemaVersion`.
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The normative byte encoding is [`docs/crypto.md` §4](../crypto.md). It is fixed-width
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binary rather than delimited string concatenation, so that no field value can forge a
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field boundary.
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5. **Layered public-key trust** — see Consequences.
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## Consequences
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### What this buys
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The AAD binding is the most valuable structural property here, and it is not something ACLs
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can provide. A malicious server cannot paste credential A's ciphertext onto host B, cannot
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roll a row back to an earlier key generation, and cannot replay a revoked grant: each of
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those changes the AAD and fails the authentication tag on the client.
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A stolen database dump, a rogue administrator, a TLS-terminating proxy and the relay
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operator all see ciphertext only. OIDC account takeover alone yields nothing readable.
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### What it costs, stated plainly
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- **Revocation is not retroactive and cannot be.** A removed member keeps whatever they
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already downloaded, along with the cached keys. Rotating the vault key protects only items
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written after the rotation. The only real remediation is rotating the SSH credentials
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themselves, so offboarding is built around a credential-rotation checklist rather than a
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"revoke access" button that implies more than it delivers.
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- **`Connect` cannot be a security boundary.** SSH terminates on the client, so opening a
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session requires the credential's plaintext on that machine. "May connect but may not view
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the key" is unenforceable in this architecture. The flag exists as a UI hint and must never
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be documented as access control.
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- **Forgotten passphrase with no recovery code and no enrolled device means permanent loss**
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of personal vault contents. Team vault contents survive, because a remaining member with
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`Share` can re-wrap. That asymmetry is a feature: it makes team vaults the right default
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even for a team of one plus a backup admin.
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- **Public-key distribution is the real security boundary.** Every guarantee is downstream of
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"the key I wrapped to is really Alice's". Four layers, deployed together: an IdP-signed key
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binding (the enrollment statement's hash is the `nonce` in an ID token, verified against
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JWKS fetched directly from the IdP and not proxied through us); TOFU fingerprint pinning
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with blocking warnings; an append-only key log whose head is embedded in every signed
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grant, so a forked view must stay consistent forever to go unnoticed; and safety numbers
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for out-of-band verification.
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The residual is honest and must stay in the docs: this makes the IdP a key-distribution
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trust root, and in a self-hosted deployment the person running Keycloak is frequently the
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person running DodoSSH. It raises the bar from "one compromised service" to "one
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compromised service plus a detectable artefact in the key log" — not to zero.
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- **No server-side session recording is possible** in relay mode, since the relay forwards
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only SSH ciphertext. See [ADR 0004](0004-relay-authorization.md).
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- **Metadata leaks.** The server sees item counts, sizes, timestamps, access patterns and the
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complete sharing graph regardless of settings. Host addresses are plaintext when relay is
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enabled for that host; see [ADR 0004](0004-relay-authorization.md) for why that is a
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security requirement rather than a convenience.
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- **The connection and activity logs widen that leak, deliberately.** They are ordinary vault
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items — every field sealed, no plaintext column of any kind, not even a timestamp — but
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there is one row per connection and one per keychain edit, and rows have `updated_at`. So
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the operator can read a user's connection *rate and timing* off the change log without
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decrypting anything: how many machines somebody touched this morning, and at what hour they
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stopped. That is a real increase over what item counts alone gave away.
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It is the price of the logs being auditable at all. Kept on the machine that produced them
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they cannot be read by an administrator, cannot survive a reinstall, and cannot be checked
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against anything — which makes them a diagnostic rather than an audit trail, and the point
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of them is the audit trail once shared vaults land. Retention bounds the exposure rather
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than removing it: ninety days or five thousand entries per kind, whichever bites first.
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Two things keep it as narrow as it can be. The payload records the host's *label* and the
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address as dialled but **not** the SSH username — "who in this organisation opened a shell"
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is the audit question, and "which account they logged in as" is a detail of the host, whose
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own logs already have it. And the activity log records the **names** of the fields that
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changed and never their values — the same rule
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[ADR 0006](0006-observability-stack.md) imposes on the server's own `audit_event.detail`,
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arrived at independently on the other side of the encryption boundary.
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- **Supply chain becomes the largest practical hole.** An operator who wants the secrets
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attacks the client, not the crypto. Release signing with a key not held by the server, and
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eventually reproducible builds, matter more here than in a conventional product.
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### Rejected
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- **Server-side envelope encryption** (KMS-held master key). Far simpler and it would permit
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a recording bastion, but a server compromise or a rogue admin exposes every credential.
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That is the exact promise the product exists to avoid making.
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- **Admin escrow of user identity keys.** Turns every operator into a silent global reader
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and destroys the property being sold. Non-negotiable. Team-scoped break-glass escrow with
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Shamir M-of-N is a separate, opt-in, clearly-labelled M5 feature.
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- **Storing an `Argon2id(passphrase)` verifier server-side** so the server can pre-validate.
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It creates an offline-crackable verifier on the very server being defended against, for no
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gain: the AEAD tag on the bundle wrap already proves the passphrase.
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