240aadb746c720c0ab016e355b683fe5fbd582d8
5
Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
 jaap-jan
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04faef6597 |
Move files to and from a host over SFTP
M2's file transfer, built bottom-up: an SFTP session on the SSH layer, a transfer queue in a project of its own, and the two-pane browser the design asked for replacing the screen that said it did not exist. Remote listings carry names, sizes, modification times and a real drwxr-xr-x — nothing in this repository could render a POSIX mode before — and the queue moves one file at a time with progress, throughput and resume. The design import assumed this would be an SFTP subsystem channel on ISshConnection, beside the shell on a transport that is already up. SSH.NET does not offer that: SftpClient derives from BaseClient and owns its own transport, and there is no supported way to hand it an SshClient's session. So file transfer opens a second authenticated connection, and it is named for that rather than dressed up as a channel — OpenSftpAsync is on ISftpSessionFactory, not on a connection. The difference is visible to a user: the host records a second login, and a host whose password is typed each time asks for it again on this screen. It goes through the same host key gate, the same pin and the same two refusals a shell does, so a fingerprint approved for a terminal is approved here and one approved here reaches the other machines with the next sync. docs/design-import-gaps.md is corrected, and marked as the one row where what shipped differs from what it predicted. Nothing is written at its final name until it is complete. Every transfer goes to a .dodossh-part file beside its destination and is renamed into place at the end, so an interrupted transfer can never be mistaken for a finished one — which matters most for what this screen is actually for, which is copying a build artefact onto a server and then running it. A destination that already exists is refused outright rather than overwritten: the queue has no way to ask, and silently replacing a file somebody's process is serving is the worse of the two failures. The remote pane has DELETE and MKDIR so that refusal is not a dead end. A test against the container pins the assumption underneath all of this — that SFTP's rename does not clobber. Resume works within a run of the application and not across a restart, and the limit is deliberate rather than unfinished. Nothing records which source wrote a part file, and resuming one on the strength of its name matching is how a corrupt artefact gets delivered with nothing reporting a failure; a part file found at startup is started over. Making it survive a restart needs the preferences store this client still has not got. The offset a resume starts at is the part file's own length rather than the transfer's recorded progress: a cancellation can land between a write completing and the counter moving, and only one of those two is a fact about the bytes that are there. The queue and its connection outlive a lock, as shells do. LockAsync already argues that locking must not destroy work in flight — it is what somebody does when they walk away from the machine, which is exactly when a long transfer is most likely to be running — so TransfersViewModel is created once and the vault is attached on unlock and detached on lock. What locking takes is the host list, and it has to: those rows carry decrypted secrets. DodoSSH.Client.Transfer is a new project rather than more of Client.Ssh. The two answer different questions — one is about reaching a host, the other about moving bytes and what to do when moving them stops halfway — and this is the only client project that deliberately touches the local filesystem. Three defects the tests found, none of which review would have. SftpPath.Name answered an empty string for the root. NavigateRemoteAsync wrapped itself in the busy guard, so navigating from inside another command did nothing at all and the remote pane simply stayed empty after connecting, with no failure anywhere to explain it. And opening an SFTP session per test made two handshakes per test — this client learns a host key by being refused — which pushed the SSH assembly past sshd's MaxStartups and failed a different few unrelated tests each run; the session is shared through the fixture now, with the reason written where the next person will hit it. 1004 tests green across 18 projects, 24 of them new: the SFTP subsystem against the OpenSSH container, the queue against a real temporary directory and a fake host, and three more layout measurements because a screen this window has never laid out is a screen never checked. Not verified: the screen has not been looked at running. The layout harness measures it at the window's minimum in three shapes, which is the class of defect that has shipped here before, but reaching it in the application needs the compose stack, the migrations, the API and a browser sign-in. What is still absent — the status bar's transfer count, dragging between the panes, transferring a directory, and sftp over a bastion — is in docs/design-import-gaps.md. |
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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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49f617b450 |
Wire the Avalonia shell to the vault
The host list now comes from the vault instead of from a form. A fresh machine takes a server URL, signs in through the browser, enrolls, and from then on opens with the passphrase alone. DodoSSH.Client.Session is the composition layer: where a profile lives, how it unlocks, and how a machine gets one. ClientPaths picks a non-roaming per-OS directory — %LOCALAPPDATA% and never %APPDATA%, because a SQLite cache that roams between two machines is a corrupt one, and each machine's outbox is its own. SessionOpener needs no transport at all and could not reach one if it wanted to; that is the offline unlock, asserted rather than asserted about. A wrong passphrase, a stale KDF and a grant revoked by a rekey are three different answers, because the remedies are three different things and telling someone to retype a passphrase that was never the problem is worse than saying nothing. The shell's states are the onboarding story. The recovery code gets its own state that cannot be clicked past: it exists for one moment, losing it with the passphrase loses the vault, and there is no server-side reset by design. It is dropped from memory on confirmation rather than merely hidden. Sign-in is a delegate over IVaultServer, so the whole state machine runs in a test against an in-memory server — no browser, no identity provider, no toolkit. The view models are plain observable objects, which is what makes that possible. What it does not cover is whether the XAML binds to the right names; that needs a rendered tree and Avalonia.Headless, and is its own piece of work. Three things found by doing it rather than by reading it: - Pooled SQLite connections keep the database file open after the last context is disposed. On Windows that means locked, so the application could never replace its own cache — and a test could not clean up after itself, which is how it surfaced. Dispose now clears the pool. - EF's SQLite provider puts the database in WAL mode, so the cache is three files. A comment in ClientCacheFactory claimed the opposite; reading PRAGMA journal_mode off a real launch settled it. WAL is the right mode here — a sync pass writes while the interface reads — so the comment was wrong on the merits as well as on the fact. - Enrolling a device key with nowhere to keep the private half would put a wrap on the server nobody can open and make the device list claim this machine can unlock without a passphrase. Device binding is now optional and the shell declines it until the OS keystore is wired. Verified on Windows: the client created %LOCALAPPDATA%\DodoSSH\cache.db and migrated it on first launch, and msedgewebview2 held an established connection to the data plane while the unlock overlay covered it — which is the point of covering the WebView rather than collapsing it, since a NativeWebView that is never laid out is never realised. 630 tests, up from 593. The recovery-code gate and the offline unlock were each verified by breaking them and watching the right test fail. Still to do for M1's actual definition of done: the manual run against the real API and a real Keycloak. Credentials are not a synced entity type yet, so a connection still asks for a password, and the interface says so rather than implying otherwise. |
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jaap-jan
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5fccd53824 |
Add the Avalonia app and the xterm renderer, and fix two real bugs
The terminal works end to end. A new integration test drives a real sshd in a container through a real PTY, the real pump, the real loopback WebSocket with its token and origin checks, and a ClientWebSocket standing in for the page: the login banner arrives, typed input round-trips, and `stty size` reports the 100x30 the session asked for. The only untested link left is xterm drawing bytes it was handed. The WebView is de-risked on Windows, which was the plan's largest risk. Not by assertion: with the app running there is an established TCP connection from msedgewebview2 to the data plane port, so WebView2 launched, navigated to the loopback page, executed terminal.js, and completed the WebSocket handshake against the real token and origin checks. Linux remains unproven and the package's own release notes now corroborate the concern -- Linux uses a WPE backend, and it ships a NativeWebDialog described as useful where embedded WebViews may be unavailable. Two bugs found by building it, both of which would have shipped: - ShellStream.Write buffers and needs an explicit Flush. Without one a keystroke is accepted, reported as written, and never reaches the remote: the terminal displays output perfectly and simply stops responding to input. SSH.NET's own WriteLine flushes, which is why the earlier spike never hit it. Found by isolating the pump against real SSH and reading BytesRead=51 -- banner and prompt through, nothing after. - The Windows app manifest needs a supportedOS list, or Avalonia's native control host fails outright and the terminal never starts. Also fixed a genuinely flaky test I happened to catch: SyncCursorTests tampered with the *last* base64url character, whose low bits the decoder ignores when the input length is not a multiple of three -- so a tampered cursor sometimes decoded to identical bytes and verified. It failed roughly one run in thirty, depending on a random key. Now tampers the penultimate character, which is fully significant at every length; 40 consecutive runs are clean. xterm 6.0.0 plus the fit and webgl addons are vendored as UMD bundles rather than built with npm, so a clean clone needs only the .NET SDK. Provenance and licences are recorded next to them, along with the UMD global names terminal.js depends on -- a bundle that switched to ES modules would load without error and leave Terminal undefined. The renderer acknowledges output from term.write's completion callback, not on receipt. Acknowledging early would return flow-control credit for bytes the screen has not caught up with, which is the one thing the credit window exists to measure. TerminalWorkspace moved into DodoSSH.Client.Terminal: it has no Avalonia dependency, and having it there is what let the end-to-end test exist at all. 404 tests pass, zero warnings on a clean rebuild, format clean. |