d1700f5a3490fb296c27d6d385b4451554b21ea3
6
Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
 jaap-jan
|
94e11f5e38 | update packages | ||
|
jaap-jan
|
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
|
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
|
70b3290a77 |
Bind an SSH key to a host instead of picking one per connection
A host now names the key it authenticates with, or none, as a field in its encrypted payload — so the choice follows the host to every machine rather than being made again each time somebody connects. The per-connection "Use key" switch it replaces was a stopgap for not having this, and keeping both would have left two mechanisms answering one question. This is the first payload schema version bump, and it does not work the obvious way. A host is written at the *lowest* schema version that can represent it: one that binds a key is written at 2, one that does not is still written at 1, byte for byte as it was before the field existed. The version is what makes an older client refuse to edit an item, so stamping 2 unconditionally would mean upgrading a single machine and renaming a single host made that host uneditable on every machine that had not upgraded yet. Confining the cost to the hosts that actually use the field is the difference between a team noticing a bump and a team being blocked by one. HostSecretCodec states the rule so the next field added follows it, and a test pins the version-1 bytes against a literal rather than against the codec, because the claim is about history: every host already in every vault has to re-encode to what it encoded before, or the first sync after an upgrade would push the whole vault as changed. A binding is an item id, not a copy of the key — a second copy of a private key is one that goes stale — which means the reference can dangle when the key is deleted on another machine. Both places that meets are handled the same way, by refusing rather than falling back: - Connecting to a host whose key is gone is refused outright. A host somebody deliberately set up for key-only access must not quietly start offering a password. - Opening such a host in the editor keeps the binding, selected, labelled as missing. The quieter version of the same failure is someone editing the port and saving, silently converting the host to password authentication with nothing ever having said so. Two things this found by being falsified: - The merge was untested for the new field, and "just take the server's value" passed the entire suite — a local binding change would have been discarded with no conflict recorded. HostSecretMergeTests already had a test written for exactly this class of omission; it simply had not been extended. - Adding a nullable field exposed a defect in HostSecretMerge.Field: it short-circuited when the discarded value was null, so the formatter never ran for the one case where null is a value rather than an absence, and a field whose absence has a name could not report it. Now the formatter always runs, and "no key" appears in the conflict log where an empty string used to. Also fixes eight nullable warnings in SyncEndpointTests left by the server-side SSH key commit, which had omitted the null-forgiving operator the rest of that file uses. They were invisible until an unrelated change forced the project to recompile. The end-to-end slice now binds its host to its key, so a schema-version-2 payload goes through the real API, the real PostgreSQL and back out on a second machine. 745 tests green. Zero warnings, dotnet format clean. |
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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. |
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jaap-jan
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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. |