3 Commits
Author SHA1 Message Date
jaap-jan 9608d73747 Come back from a sync position the server will not accept
ci / build and test (push) Failing after 2s
"The server returned 400: The sync cursor is not valid for this vault. Resync
from the beginning." told the user exactly what to do and gave them no way to
do it. The cursor is the only thing a pull sends, so the refusal was permanent:
the next pass read the same stored cursor and was told the same thing, once a
minute, for ever. And because the pull runs first, the exception ended the pass
before it reached the outbox — so the vault stopped receiving other machines'
changes and stopped sending its own. A machine that met this went quietly
read-only until somebody deleted its cache.

The engine now does what the message asks. A pull refused with the
invalid-cursor problem code — the code, never the prose, which is free to
change — drops this vault's position, writes that down, and reads the log again
from the beginning. The restarted request carries no cursor, which is the one
position a server cannot reject, so the retry cannot loop; a refusal of that is
rethrown rather than retried, and a restart is allowed once per pull. The
position is saved before the replay starts, so a process that dies halfway
through begins the next one from the beginning too rather than meeting the same
refusal again.

The mirror is deliberately kept. Replaying rewrites every row the server still
has and applying a change is a blind overwrite, so the re-pull repairs the
mirror on its way past; clearing it first would claim more than the evidence
supports — the position was refused, not the contents — and would leave a
machine that lost its connection mid-replay with less than it started with.
That leaves one gap, named in the remarks rather than left to be discovered:
once tombstone collection exists, a replay stops carrying deletions older than
the retention window.

None of the causes are the user's doing — a rotated cursor signing key, a vault
served from a restored database, a cache copied between machines — so nothing
asks them to decide anything. The report carries ResyncedFromStart and the
status line says the position was not recognised and the vault was read again.
It is kept out of NeedsAttention, because nothing is outstanding, but the
background pass breaks its usual silence for it: a sync that pulled the whole
vault on a day nobody changed anything otherwise reads as a fault.

The fake server grew a switch that refuses cursors the way a rotated signing
key does, including ones it minted itself. Three cases: the vault is re-read
and the change on the far side of the refused position arrives; the edits
waiting in the outbox are still pushed in that same pass, which is the half
that made this worth recovering from rather than merely reporting; and a server
that refuses the beginning itself is surfaced instead of replayed against.

dotnet build is clean at zero warnings, dotnet format is clean, and the sync
and app suites pass — 109 and 101.
2026-07-31 11:32:14 +02:00
jaap-jan e3fd3e1728 Sync and authenticate with SSH keys on the client
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.
2026-07-29 20:27:23 +02:00
jaap-jan 8d2416a602 Add the encrypted local cache and the sync client
Three new client projects, and the wire-contract fix they needed.

DodoSSH.Client.Domain holds the decrypted item model and the three-way
merge, with no I/O at all — so the suite that decides whether a
credential can be lost runs in milliseconds with nothing to mock.
Scalars defer to the server on a genuine clash so every replica resolves
the same triple identically and two clients cannot ping-pong; directives
merge per name so two people each adding one both keep theirs; the jump
chain merges as a whole value because its order is the route. Whatever
loses is returned rather than dropped.

DodoSSH.Client.Storage is EF Core on SQLite, no SQLCipher: the rows are
already ciphertext, so an encrypted file would protect protected bytes
at the cost of a native dependency. It keeps the server's state and the
outbox in separate tables, which is what preserves the common ancestor a
merge needs. One pending operation per item, enforced by a unique index.

DodoSSH.Client.Sync is the pull/apply/push loop. Pulling never decrypts
— a change with no local work pending is plumbed as ciphertext — so a
first sync of thousands of items does not run twice as many AEAD
operations for nothing.

Contracts: EncryptedPayload gains WrappedDataKey and DataKeyId. The
specification has required a per-item data key since crypto.md §3, the
columns have existed since the first migration and DshAad.ItemPayload
binds the id, but this record had nowhere to put either — so a
spec-compliant item could not be transmitted at all. Found by writing
the client that has to produce one. Also closes a hole in
AadResourceType, which had no value for the HostTag and HostCredential
that SyncEntityType has always listed.

Four bugs the tests found, not review:

- SQLite refuses to order or compare its own DateTimeOffset mapping, and
  throws at execution rather than model build. Collecting tombstones and
  listing conflicts are both that shape, so this was a crash waiting for
  the first user with a deleted host. Timestamps are integers now, by
  convention so a later field cannot be the one left unconverted.
- SQLitePCLRaw 2.1.11, which EF resolves, is covered by
  GHSA-2m69-gcr7-jv3q. Pinned forward as a family.
- Resurrecting content from a remote deletion cleared the original
  before queueing the copy. Two transactions, so a crash between them
  lost the work; reversed, and the rescued id is derived from the
  tombstone so a replay coalesces instead of duplicating.
- Several equality assertions went through Shouldly's ShouldBe, which
  compares IEnumerable element-wise and so tested nothing about the
  Equals these types exist to provide. Corrected; the falsification that
  caught it went from 2 failures to 6.

The push response's cursor is deliberately ignored. It sits after this
client's own writes, so adopting it skips anything another client
committed at a lower sequence in the window between a pull and a push —
permanently. Re-reading one's own writes is idempotent and costs a page.
The Contracts doc that invited the shortcut now says so.

593 tests, up from 448. The delete-versus-edit rules, the ancestor
retention, the fresh operation id on coalesce and the cursor safeguard
were each verified by breaking them and watching the right test fail.
2026-07-29 10:27:37 +02:00