94e11f5e38c528373556d020f6c8284e1023720d
7
Commits
| Author | SHA1 | Message | Date | |
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 jaap-jan
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94e11f5e38 | update packages | ||
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jaap-jan
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211eba0666 |
Keep host key trust in the vault, and make it withdrawable
A fingerprint approved once is now approved on every machine and survives a
restart, because host key trust is a vault item type rather than a dictionary
that dies with the process. InMemoryKnownHostStore was what shipped, so the user
was asked to verify a fingerprint on every single connection — which is the gap
most likely to train somebody to click through the one warning that actually
matters. A warning that appears when nothing is wrong teaches that nothing is
ever wrong.
The fourth item type, and like the third it cost no sync logic: a row, an EF
configuration, a migration, a server kind; a secret, a codec, a merge, a cipher,
a repository facade and a session property. One row in the client registry. The
reconciler, the mirror, the repository, the outbox and the pull filter were not
touched. SyncEntityType.KnownHostKey and AadResourceType.KnownHostKey were
already reserved, so neither the contract nor docs/crypto.md changed.
One item per (host, port, algorithm), because a server legitimately offers
several host keys and which one gets negotiated is not ours to predict. Pinning
per endpoint would make an algorithm change indistinguishable from an attack.
The label is derived rather than stored, which is the one place this type
departs from the other three. A user never names a pin — there is nothing to
name it after but the three fields it already has — and a stored label is a
second copy of data that can disagree with the first after a merge. Relabel
returns the secret unchanged, and says why.
The store answers the handshake without touching the disk. SshNetConnectionFactory
calls FindAsync from inside SSH.NET's synchronous HostKeyReceived event, over
.GetAwaiter().GetResult(), which cannot be avoided; doing SQLite I/O plus an AEAD
open per lookup there would put the handshake behind the cache. So decryption
happens in OpenAsync and RefreshAsync — on unlock and after each sync pass,
exactly where the host and key lists already reload — and FindAsync is a
dictionary read under a lock with no await inside it.
That snapshot is where the one real bug in this change lived. Install originally
merged the live pins over the freshly loaded snapshot, to protect a TrustAsync
that had landed while the read was in flight. It would also have resurrected
every pin the user had just forgotten, and stopped a withdrawal made on another
machine from ever taking effect — the store would have healed the deletion back
into existence on every refresh. Replacing wholesale and discarding the read
instead is correct because writes are the rare case: every write bumps a
generation counter, and a refresh whose stamp is stale throws itself away rather
than winning. Nothing found this but reading the method again; it is the kind of
mistake that passes every test written before it, because the test that catches
it is the one the bug tells you to write.
Forgetting is new, and persistence is what made it mandatory rather than
convenient. A mismatch is a hard refusal with no way to continue — deliberately,
and that stays — so pinning a key permanently is also a way to make a
legitimately rebuilt server permanently unreachable. Before this change the pin
died at exit and the problem solved itself; now it does not.
ForgetAsync drops every algorithm for an endpoint, and it is reachable from the
host editor rather than from the warning. Putting it on the mismatch banner would
have made it two clicks from "this may be an attack" to "connect anyway", which
is the affordance the hard refusal exists to deny. The banner already promised
the key could be removed in the host's settings; that promise is now true and
points at the button.
Trust recorded on another machine becomes visible at the next sync pass, not
immediately, and that is a decision rather than an oversight. The failure it
produces is a first-contact prompt for a host a colleague approved a minute ago:
answerable, and self-correcting on the next pass. The opposite trade — polling
the vault on the handshake thread to close a one-minute window — buys nothing
and costs the property above. The dangerous direction is not reachable at all: a
pin recorded here enters the snapshot as part of recording it, so a refresh can
never discard a local trust decision.
The server learns nothing, and this is the item type where the temptation was
real. A plaintext host column would let a known-hosts screen sort and page
without decrypting anything, and it would hand the operator the map of every
user's estate — assembled, as these things are, out of facts that are each
individually harmless. A host row concedes an address only when relay is
switched on and the database refuses to store one otherwise (ADR 0004); there is
no equivalent excuse here. The table has no column to put one in, and the EF
configuration says so where somebody adding it would be standing.
Two things about the migration in this commit are worth knowing, because both
came out of getting it wrong.
It was hand-written first, including its .Designer.cs, and that version is not
what is here. Verifying it turned up something that had been quietly assumed:
Migration_AppliedCleanly_WithNoPendingModelChanges does not check the model
snapshot. It asserts that migrations applied and that none are pending, which a
wrong snapshot satisfies perfectly — the snapshot only matters as the diff base
for the *next* migrations add, so an incorrect one passes the whole suite and
corrupts the following migration instead. The real check is to generate a
throwaway migration and confirm its Up and Down come out empty. They did, and
the generated designer was byte-identical to the transcribed one across all 1255
lines, so the hand-written work was in fact correct.
Then dotnet ef migrations remove --no-build deleted the wrong migration. With
--no-build the tool reads the previously compiled assembly rather than the files
on disk, and the probe had just changed which migration was last, so it removed
AddKnownHostKeyItem and reverted the snapshot. That turned out to leave exactly
the right diff base, so the migration here is EF's own output rather than a
transcription — a better outcome than the one that was interrupted, arrived at
by accident. Never pass --no-build to migrations remove.
Mutation tested, all three sabotages detected: dropping the algorithm from
KnownHostIdentity.For, merging instead of replacing in Install, and pointing
KnownHostKeyCipher at PortForward — which is what a cast from the wire enum's 10
would silently produce. Each is caught both by an assertion about the mechanism
and by a behavioural test that never mentions it; the resource-type sabotage is
caught by the table from
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jaap-jan
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e24012b039 |
Sync credentials as a vault item type, and bind one to a host
Closes the largest remaining M1 gap in the data layer: a username and password can live in the vault, sync between machines, and be named by a host as how it authenticates. What is not here is the interface for creating one — see the end of this message. The third item type, and the first one that cost almost nothing to add. Server: a VaultCredential row, an EF configuration, a migration, and a CredentialKind. Client: a secret, a codec, a merge, a cipher, a kind, a repository facade and a session property. No new reconciliation logic, no change to the sync engine, no client cache migration. That was the whole point of the item-kind seam, and this is the evidence it holds. The narrowest type of the three on plaintext, and not for symmetry. A host has a deliberate concession — the relay needs an address it can resolve. A key has a fingerprint, public by nature, which this client still declines to send. A password has no part that is safe to expose: not its length, not a hash, not a hint. So CredentialKind refuses every plaintext field there is, hydrates none, and the table has no column to put one in. HostSecret.CredentialId is the password counterpart of SshKeyId, and the two are mutually exclusive. SSH itself would happily try a key and fall back to a password, but a host naming both leaves "how does this authenticate?" without a single answer — the interface, the connect path and the user would each be free to guess differently. TryValidate refuses it. One consequence was not anticipated: "a full host" stops being a coherent idea, which is what broke AFullHost_RoundTrips and is now written into that test. The schema version became a ladder rather than a maximum: credential-bound is 3, key-bound is 2, neither is still 1. Adding credentials therefore does not drag every key-bound host in every vault onto a version that clients understanding keys perfectly well would refuse to edit. A test pins exactly that, because it is the property the whole content-dependent-version rule exists to provide, and the obvious implementation would quietly lose it. Two tests had become false and said so: - Push_AnUnsupportedEntityType_IsInvalidNotAFailedBatch used Credential as its example of a type this server does not implement. It now asks the server's own registry what is still missing, so it cannot go stale again, and skips with a reason if that set ever empties. - ThePullFilterNamesEveryTypeThisBuildSynchronises pinned the exact list, which is what it is for. Also fixes ten nullable warnings — eight in SyncEndpointTests, two in a test file added earlier today. Neither set was introduced here; both were invisible until an unrelated change forced their project to recompile, which means the zero-warning claims made earlier in this work only ever covered what happened to be rebuilt. 777 tests green. Zero warnings, dotnet format clean. Not done, and deliberately: the credential interface. The vault column is 340 pixels wide and already holds two lists and two editors, kept from clipping its own buttons at the window's minimum height only by the one-editor-at-a-time rule added earlier today. A third list and a third editor would recreate that defect rather than avoid it, so the column needs a shape decision first. Credentials sync; they cannot yet be created in the interface. |
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jaap-jan
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e93acc856f |
Sync SSH keys as a vault item type, over a shared write path
The private key now lives in the vault as ciphertext, syncs between a user's machines, and is stored on the server so it can later be shared — sharing itself needs M3's signed grants; this is the storage that makes it possible. More was already reserved than expected: SyncEntityType.SshKey, CryptoSpec.AadResourceType.SshKey, ChangeEntityType.SshKey, SyncPlaintextFields.PublicKeyFingerprint, and SshPrivateKeyCredential wired through PrivateKeyFile over a MemoryStream so a key never touches disk. The frozen contract and crypto spec needed no change at all. What was missing was the server. Rather than copy the push path per item type — version check, change-log append, exactly-once receipt, advisory lock — it is now written once over IVaultItem, with everything type-specific behind IItemKind: which table, which plaintext columns, and what those columns must satisfy. Ten copies of that logic by M5, with a fix applied to nine, is the outcome this avoids. The refactor landed first with no behaviour change, so all 66 existing Host tests were the regression net, and they stayed green. An interface rather than a base class, deliberately: EF Core maps an inheritance hierarchy when it can see one, so a mapped base would quietly become a table-per-hierarchy discriminator across item types — the very arrangement per-type tables exist to avoid. ssh_key mirrors host and pointedly has no relay trio. That is the argument for separate tables rather than one wide item table: the columns a host needs are columns a key must never have, and a shared table could only make them nullable and trust the code. A key carrying a relay target is refused with a reason rather than silently dropped. A key hydrates PlaintextFields as null, not an empty instance — the difference is visible on the wire, because an all-defaults instance still serialises "relayEnabled": false and invites a reader to believe the setting exists and is off. It has none. Two things now defended by tests rather than by comments. Each kind states its own ChangeEntityType instead of casting: the two enums agree numerically but do not even share member names (Host against SshHost), and filing key changes under the host type is silent sync corruption — sabotaging it fails three tests. And EntityTypeAlignmentTests asserts the two enums stay aligned in both directions and in count, which nothing did before. The client half is next: SshKeySecret, its codec and merge, the cipher, a repository, and the UI. Note for that work — SyncEntityType.SshKey is 3 while AadResourceType.SshKey is 6, so a cast between them would seal key ciphertext as a vault and nothing would fail. |
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jaap-jan
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3829217e8a |
Add sync engine: cursors, push/pull, and the advisory-lock ordering proof (M1)
The vault write path. Push is the only way items change — no per-entity POST/PUT/DELETE — so one place enforces revisions, the change log and access control. The concurrency hazard, now proven rather than asserted: bigserial assigns sequence values when the INSERT runs, not at commit, so transaction A can take sequence 5 while B takes 6 and commits first. A reader polling in between sees only 6, advances past 5, and never learns about it. AdvisoryLockOrderingTests reproduces that gap WITHOUT the lock first — otherwise the with-lock test proves nothing, since it would pass just as happily if the interleaving never occurred — then shows pg_advisory_xact_lock removes it, and that 12 concurrent writers produce no gaps. Cursors are opaque and HMAC-tagged, and carry their vault id. 29 unit tests cover the rejections, which are the point: an accepted-but-wrong cursor is silent data loss, strictly worse than an error a client can resync from. Rejected: tampered tag, tampered payload, foreign signing key, a legitimately-issued cursor from another vault, truncation, and hostile input (never throws — cursors come from clients). Push semantics: - 200 even on partial failure, with per-operation status, so one stale item cannot block everything a client queued while offline. - Conflict returns the server's current row for client-side three-way merge. The server cannot merge ciphertext, so never last-writer-wins. - opId receipts make retries exactly-once per operation, not per batch — a client retrying a partially-overlapping batch after a timeout would otherwise double-apply what landed. - A tombstone beats a late upsert, and delete clears hostname/port: leaving the address would keep the server able to resolve a host the user believes they deleted. - Relay field validation mirrors the DB CHECK so a bad request is a clear Invalid rather than a constraint violation surfacing as a 500. Authorization goes through IVaultAccessService, which returns the same answer for "absent" and "forbidden" — distinguishing them is an existence oracle for other tenants' vault ids. Team vaults are explicitly denied until M3 rather than falling through to a permissive default. JIT provisioning keys on (issuer, subject), never email, and handles the concurrent-first-request race via the unique index. Renamed two domain types: Host -> SshHost, because Host collides with Microsoft.Extensions.Hosting.Host in every file of a web project, and SyncChange -> VaultChange to stop it colliding with the Contracts DTO of the same name. Aliasing at every use site would have been permanent friction. Worth noting: `ef migrations has-pending-model-changes` reported clean after those renames even though the snapshot still said "DodoSSH.Domain.Host" — it diffs tables, not CLR type names. The snapshot was regenerated and the emitted DDL diffed against the previous artifacts/schema/v0.1.sql to confirm the rename produced no schema change. Also removed ConfigureAwait(false) from test methods: xUnit1030 flags it as bypassing parallelization limits, which is why MA0004 is suppressed in test projects. Verified: 0 warnings on a clean rebuild, 146 tests pass (up from 122), format clean. Endpoint-level tests are the immediate next step: they need a WireMock OIDC/JWKS stub and real JWT minting, so the "wrong user is denied" matrix does not exist yet for these two routes. The service-layer authorization and the concurrency property are covered. |
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jaap-jan
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eaf68c86b0 |
Add data model, DbContext and initial migration (M1)
Schema for identity, vaults, grants, hosts and the sync change log, verified against a real PostgreSQL 18 container rather than an in-memory provider: partial unique indexes, CHECK constraints, citext and identity-always columns are all provider behaviour that an in-memory fake would not exercise. Invariants pushed into the database, so they hold even when application code has a bug: - ck_host_relay_target is a security boundary, not tidiness. A host may carry a plaintext hostname and port ONLY when relay is deliberately enabled. Both directions are tested; the important one is that relay-disabled hosts cannot carry an address, since otherwise a bug would silently give the server infrastructure visibility it was never granted. - ck_vault_owner: exactly one of owner_user_id or team_id, or permission resolution would have no defined answer. - ck_vault_key_grant_recipient: member grants name a user; recovery and escrow grants are wrapped to a key and must not. - ck_user_key_wrap_kdf: a password-derived wrap without its parameters is permanently unopenable, so a partial write is rejected outright. Present from the first migration on purpose: - GrantKind (Member/Recovery/Escrow). Recovery cannot be bolted on later — every vault created before it existed would be unrecoverable by design. - team and team_membership, though team features are M3. Adding them later would mean introducing a foreign key on a live vault table. - Host.ContentKeyId, reserved for per-item content keys wrapped to individual users. - user_key as its own table, so key rotation does not require altering the user row. Two things verified rather than assumed: - Npgsql's UseXminAsConcurrencyToken helper no longer exists in EF 10, so xmin is mapped directly in XminConcurrency. The generated migration *looks* like it creates an xmin column; it does not. Confirmed by inspecting pg_attribute (attnum -2, a system column) and by grepping the emitted DDL. A test pins both, because had it created a real column PostgreSQL would have rejected the name. - EF Core is now pinned centrally. The Npgsql provider asks for 10.0.4 while EntityFrameworkCore.Design pulls 10.0.10, and because Design is PrivateAssets=all that higher version does not flow to referencing projects — producing a CS1705 in any test project referencing Infrastructure. Also commits artifacts/schema/v0.1.sql, the idempotent script, as the baseline for future upgrade tests. Verified: 0 warnings, 122 tests pass (27 new against Postgres), format clean. |
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jaap-jan
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3a81f3c90b |
Restructure into src/tests and add build foundation (M0)
Moves the scaffold to src/DodoSSH.Api and establishes the repo conventions the rest
of the milestones build on.
Structure:
- src/{Contracts,Crypto,Domain,Infrastructure,Api}, tests/{Contracts,Crypto,Domain}.Tests
- DodoSSH.slnx rewritten with src/ and tests/ solution folders
Build:
- Directory.Build.props centralises TFM, nullable, deterministic builds and
TreatWarningsAsErrors; Directory.Packages.props pins every version centrally
- packages.lock.json committed so CI restores in locked mode
- NuGet.config clears machine-level sources, which both fixes NU1507 under central
package management and makes restore reproducible off this machine
- Microsoft.OpenApi pinned to 2.11.0: ASP.NET Core 10.0.10 resolves 2.0.0, which is
covered by GHSA-v5pm-xwqc-g5wc (high, patched in 2.7.5)
Analyzers:
- AnalysisLevel is Recommended, not All. With warnings-as-errors, All turns opinionated
naming rules into build breaks and trains people to blanket-suppress.
- BannedSymbols.txt bans DateTime.UtcNow (TimeProvider), Guid.NewGuid (CreateVersion7),
sync-over-async, MD5/SHA1, PBKDF2 and SecureString
- CA1711/CA1724 disabled: both are .NET Framework CAS-era naming rules
- PublicApiAnalyzers on Contracts only, since that assembly is the client's real contract
API:
- weather-forecast template removed
- UseHttpsRedirection removed; TLS terminates at the reverse proxy and redirecting
behind one causes loops
- /healthz/{live,ready,startup}. Liveness deliberately checks no dependencies so a
transient database outage cannot restart the container and kill live SSH sessions.
Notes:
- No coverage collector yet. Microsoft.Testing.Extensions.CodeCoverage pulls an MTP 1.x
MSBuild extension that throws TypeLoadException against the MTP 2.3.x xunit.v3 brings.
Coverage gates are an M3 concern; revisit with an MTP 2.x-aligned version then.
Verified: dotnet build (0 warnings), 17 tests pass, format check clean, API serves
health and OpenAPI endpoints.
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