Public Access
e0509c6679a247d47fde16caae31c9d91dffb819
7
Commits
| Author | SHA1 | Message | Date | |
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 jaap-jan
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b2516ca7fb | Server: start a retried write transaction from the database, not from the attempt that failed | ||
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jaap-jan
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d5b1a73182 |
Move the keys when a membership changes, not just the flag
Adding somebody to a team granted them nothing readable and removing them
rotated nothing. Both were honest — the interface said so in as many words — and
both left the actual work to a button somebody had to remember to press, on a
machine that happened to hold the key. Adding now wraps every team vault this
machine can open to the new member, and removing revokes their grants and moves
each of those vaults to a fresh key that goes to whoever is left.
The rotation is where the design had to be decided rather than written. A vault
key is per generation and an item carries the generation it was sealed under, so
advancing the vault and withdrawing the old grants would make everything already
stored unreadable to everybody, including whoever pressed the button. So earlier
grants are kept: a member holds one per generation, /me serves them as
PriorKeyWraps, and VaultKeyring holds a key per generation — the newest for
writing, the item's own for reading, chosen per item on every read path. Sharing
issues one grant per generation held, because a recipient handed only the current
key would open the vault to find most of it undecryptable; revocation takes every
generation, because leaving the history behind leaves them able to read
everything written before the rotation.
The bump itself is one server transaction. POST /vaults/{id}/rekey must name
exactly current + 1 and the vault's xmin token makes that binding, so two admins
rotating at once do not both walk away believing they succeeded — the second is
refused and told to read the vault again. The server contributes the moment and
no cryptography: it cannot generate the key, cannot tell that the one it is
handed differs from the old one, and checks that the caller held the old one the
only way it can, by requiring a live grant at the current generation.
What this does not do is re-encrypt what is already stored, and the product says
so rather than the reassuring version: everything written from the rotation
onwards is unreadable to the person who left, and nothing about the past changes.
That half is deferred and is safe to add incrementally precisely because a vault
at mixed generations stays readable. ADR 0010 records the alternatives — revoking
the old grants, chaining each key under its successor, re-sealing every item in
one request against a server that caps a push at 500 operations — and why each
was rejected.
Two things fell out of the change rather than being asked for. The grant listing
would have shown a member once per generation, so it now returns one row per
holder carrying the best key they hold, which is what makes a row below the
vault's generation mean "still owed the new key". And MarkUnreadable gives up the
write target as well as reporting: a client whose vault was rotated elsewhere
would otherwise have gone on sealing items under its superseded key — readable to
its author, unreadable to everybody else, with nothing to show for it.
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jaap-jan
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95816de0c5 |
Share a vault with a team, without the server holding a key
M3's teams, sharing and ACLs. Teams with roles, a public-key directory, the append-only key log served for clients to check it against, team-owned vaults, and vault key grants wrapped by a client and stored opaquely by the server. VaultAccessService resolves team membership to PermissionFlags, so a viewer may pull and may not push; the desktop client reads and syncs every vault it holds a key for, and a real TEAMS screen replaces the one that said it did not exist. No migration: team, team_membership, vault.team_id and vault_key_grant have all been there since the first one, which is what carrying two unused tables bought. Membership is authorisation. A grant is access. The obvious model is one concept — "access", with a role attached, handed out by the server — and this architecture cannot implement it: a vault key is sealed to each member's X25519 key, and only a client holding the plaintext can seal it for somebody else. So "give Bob access" decomposes into a database write and a wrap, which happen on different machines. Adding a member makes the server serve them the vault; it cannot make it readable. VaultSummary.WrappedVaultKey is null in the meantime and the vault appears in their list saying it is waiting for a key, because hiding it until a grant existed would have been tidier and would have implied the server was the thing granting access. The screen says the same thing after every add, in the status line. ADR 0009 records the whole decision. Sharing verifies or refuses. A directory lookup is a claim by the server about a third party's public key, and wrapping to an unverified claim hands the vault to whoever made it — no amount of transport security helps, because the server is inside the threat model. KeyLogAudit reads the whole log, recomputes every entry's hash from its own contents, checks the chain from genesis, and refuses unless the offered key appears in it unchanged. There is no override flag: one that exists gets used on the day the log is briefly unreachable, and the resulting grant is indistinguishable from a correct one afterwards. What it still cannot promise is that the key is the right person's, so the fingerprint comes back for an out-of-band comparison and the success message says so every time. A test corrupts the fake server's log by one byte and watches the client refuse rather than warn. The roles are only the ones that are enforceable. There is no ConnectOnly, despite the design asking for one and TeamRole having room: SSH terminates on the client, so a session needs the credential's plaintext on that machine, and "may connect but may not read the key" cannot be enforced here. Shipping it as an option in a dropdown would have been a lie. Connect rides along with Read and is documented as an interface hint. Removal is named for what it does — it revokes grants and flags the vault for rekey, and claims nothing about what is already on somebody's laptop. Three things are deliberately absent, and each is a refusal rather than an omission. The rekey itself, because re-wrapping every item's data key under a new vault key needs a client holding the current one; the server records that a rotation is owed and the interface reports it, which is more honest than a button that only appears to do it. Ownership transfer, because allowing an owner to be removed without one leaves a team nobody can administer. And cross-vault host key trust: a pin in a team vault is listed but not consulted at connect time, because any member with Write could otherwise pre-approve a fingerprint another member's client then trusts silently for a host in their own vault. Scoping trust properly needs a scope on the SSH connect path, which IKnownHostStore has not got; until then the narrow direction is the safe one and the cost is in the README rather than hidden. Reading now spans vaults and writing still does not. Every list on the vault and hosts screens covers each vault the keyring opened, rows carry the vault they came from, and an edit goes back to that vault rather than to the active one — writing it to the active vault would fork the item and only show up when a colleague wondered why their change never arrived. A new item goes wherever a picker says, defaulting to the personal vault and never moving on its own, because an item filed into a team's vault is visible to that team and moving it back means deleting and retyping. The sidebar heading stops naming one vault once there are two, and each row names its own. The server checks what it can and nothing it cannot. It will not record a grant for a key its recipient no longer holds, for a superseded generation, or for somebody who is not in the team — each of those would otherwise surface days later at the far end as a tag failure indistinguishable from corruption. It does not verify the wrap or the signature, and the grant service says so: that would be a convenience and never the boundary, and would put an asymmetric implementation on a machine that is supposed to hold no keys. Two bugs the tests found. TeamsViewModel's busy gate blocked its own reload, so a team created a moment earlier was missing from the list it had just been added to. And syncing every vault turned a failure from an exception into a report, which made a background pass announce an unreachable vault once a minute — the exact behaviour AnAutomaticPassThatFails_LeavesTheStatusAlone exists to prevent. The fact is recorded and the message swallowed, as it was before; pressing Sync still names the vault and the reason. Also fixes a build break this branch started with: QuickConnectTests was never updated when M2 added ISftpSessionFactory to the shell's constructor, so nothing built at all. |
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jaap-jan
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9bc28f1c0f |
Move the API onto FastEndpoints, without moving the wire
Eight endpoints today, around sixty planned. The minimal-API shape — a static
class per area holding static local functions, route and policy and name
asserted in one fluent chain with the handler somewhere below it — has not hurt
yet, and would. A handler's dependencies are parameters rather than injected, a
group's RequireAuthorization sits far from the handler it governs, and there is
no type to hang an endpoint's own documentation on. FastEndpoints is one class
per endpoint, its route and authorization in Configure(), its handler a method
on the same type.
Nothing about the wire moves, and the evidence is that the 94 existing HTTP
tests pass with zero edits to any of them. Same routes, verbs, route
constraints, status codes, operation ids, and the same RFC 9457 bodies with the
same code values. Every place the idiomatic FastEndpoints answer would have
changed one of those, it was refused:
Endpoints are registered from an explicit List<Type>, not found by scanning.
ADR 0002 rejected reflection discovery by name, and the reason it gave is
sharper here than in general — under WebApplicationFactory the scan reaches the
test assembly, so an endpoint written in a test would be registered into the
host under test. The cost is a line per endpoint that can be forgotten, which is
what the endpoint-inventory test is for. That test is the one ADR 0002 promised
and never got.
Handlers still return Results<Ok<T>, NotFound, ProblemHttpResult> from
ExecuteAsync. The union executes as an ordinary IResult, which is what keeps
problem bodies going through the host's serialiser and IProblemDetailsService,
and what keeps the compile-time record of which statuses an endpoint can
produce. No Send.* call appears anywhere; the moment one does, a response has
left the host's serialiser.
Validation stays in the feature services. A Validator<T> short-circuits before
the handler and answers with FastEndpoints' own envelope, which carries no code
— and the code is the only part of an error the client branches on. Twenty-odd
tests assert a specific code on a 400. It is banned in BannedSymbols.txt rather
than merely avoided, because the framework's documentation leads straight to it
and it looks like an improvement.
Three defects arrived with the framework and were caught in review. All three
were green at the time, which is the part worth remembering. FastEndpoints maps
GET /_test_url_cache_ unconditionally, in every environment, with no policy and
no way to opt out; it answers with the whole endpoint-name-to-route table. It is
short-circuited to 404 — by asking routing which endpoint it selected, after the
first attempt compared the request path with Ordinal and was therefore bypassable
at /_TEST_URL_CACHE_, certified by a test that only ever tried one spelling. The
default request binder writes query-string values over the deserialised body,
which would have let ?identityProviderToken=... put an ID token in a URL and from
there into every proxy log on the path; every endpoint now binds from the body
alone. And a route value read with Route<T>() is invisible to ApiExplorer, so the
generated document named {vaultId} in a path template with nothing declaring it —
invalid OpenAPI, and unusable by the client generators the document exists for.
Two changes to the surface, both deliberate. A body that cannot be deserialised
now answers with a problem document carrying malformed-request, rather than an
empty 400: FastEndpoints' default announces application/problem+json while
sending something else, and names the failing .NET type on the wire, in a
codebase that sets IncludeErrorDetails = false to prevent exactly that. And the
route table above returns 404 where it would otherwise have answered any
authenticated caller.
Each of the three fixes has a regression test that was checked by reverting the
fix and watching it fail — four failures for the route table and the binder, four
for the document. That check is the whole reason to trust them, since all three
defects passed a full green suite on the way in.
950 tests green across 16 projects, 14 of them new and no existing test edited.
Zero warnings, format clean, locked restore clean. FluentValidation, JobQueues
and Messaging are in the graph now and none is used.
Not verified: the generated document's response schemas, which differ from
before — FastEndpoints contributes its own Produces metadata. Nothing consumes
the document yet, and MapOpenApi runs only in Development behind the fallback
policy. It needs pinning if ADR 0002's build-time artifacts/openapi/v1.json is
ever built.
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jaap-jan
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f86791e817 |
Finish revoking a device, instead of half of it
ForgetDeviceAsync stopped this machine unlocking without a passphrase and left
the server's row exactly where it was, so the account went on listing a device
nobody could account for. ADR 0007 recorded that as a deliberate gap needing an
endpoint. This is the endpoint, and the two things that turned up behind it.
DELETE /api/v1/me/devices/{id}. The device row is not the dangerous half: a
kind=device wrap is the user's identity bundle sealed to a key somebody may be
holding, and that is what has to go. It goes on the foreign key's cascade rather
than a second statement, and RevokeDevice_TakesItsWrapWithIt asserts the cascade
rather than trusting the configuration to keep saying so.
Scoped to the caller's own account, which is the only authorisation check there
is. The id is an unguessable v7 GUID, but unguessable is not a permission —
without the scope one user could withdraw another's device key by pasting an id
they saw once, and the victim's next launch would ask for a passphrase with no
explanation. 404 rather than 403 for somebody else's device, so a stranger does
not learn the id exists.
Never refused for being the last device. ADR 0001 makes an enrolled device a
recovery path, so removing the last one does cost the user something — but the
machine being revoked is most likely the one they have just lost, and a server
that argued about it would be refusing the one request that has to work
immediately. The passphrase wrap is untouched either way, which
RevokeDevice_LeavesThePassphraseWrapAlone pins.
--- Two things found on the way ---
Registering twice from one machine left two devices on the account. The server
is idempotent on the public key, but the client generates a fresh key pair every
call and the keystore holds one — so the second registration orphaned a wrap
whose private half had just been overwritten, which is precisely the leftover
this change exists to remove. Registering now withdraws the previous device.
Found by a test that asserted the property and failed.
And the fakes were lying about it. FakeAccountServer's comment claimed the real
service's idempotence while handing back a fresh Guid on every call, which is
invisible until something revokes by id — at which point a test would be
revoking an id the server never issued, and passing. Both fakes now issue one id
per public key and drop the wrap with the device, as the cascade does.
--- Reachable at all ---
ForgetDeviceAsync had exactly one caller and it was a test, so "Stop unlocking
here" now sits in the account bar where "Use Windows Hello here" was. Its own
flag rather than the negation of that one: a machine with no TPM and a machine
that is already registered are both "cannot register", and only the second has
anything to take back.
No confirmation prompt, deliberately. The cost of pressing it by accident is one
passphrase and one re-registration; the cost of a dialog is a moment's
hesitation at the point somebody has realised a machine is in the wrong hands.
Offline it does the local half and says so rather than refusing. Whether this
machine may unlock itself is decided entirely by the local cache and the local
keystore — the unlock path never asks the server — so forgetting here is what
actually revokes, and "you are offline, so this machine will go on unlocking
itself" would be the worst available answer. DeviceRevocation.LocalOnly is what
the interface reports and the status line explains what is left to do.
The local half runs first for the same reason, and the keystore call is the
first thing in the method that can yield: on Windows it raises a consent dialog,
and a dialog wants the thread it was called from. That ordering is currently
load-bearing and shakier than it looks — see the open device-unlock hang.
Four mutations, all caught: dropping the user scope from the server query
(1 test), skipping the stale-device revoke on re-registration (2), skipping the
server call in ForgetDeviceAsync (2), and the earlier version of the client that
never called it at all.
930 tests green across 16 projects, 13 of them new. Zero warnings, format clean.
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jaap-jan
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db4a8ed3d3 |
Let an already-enrolled account register a device key
The first of the three pieces ADR 0007 needs, and the one that was a discovery rather than a plan. EnrollmentService.AddDevice runs only during enrollment, so without an endpoint the device-unlock feature would have reached accounts created after it shipped and no others — which is to say none of the ones that exist. The code even said so: "the devices endpoint sets it properly when it lands." POST /api/v1/me/devices takes a name, an X25519 public key and the bundle sealed to it, and writes a device row plus a UserKeyWrapKind.Device wrap. Possession is proved by construction, so there is no challenge. The wrap is the secret bundle sealed to the supplied public key, and only something that has opened that bundle can produce it. A caller who seals the wrong bytes registers a device that cannot unlock, which harms nobody else; the server cannot tell the difference and must not pretend to, because it holds no key that opens either. That is also why the client must be unlocked to call this at all. It is the one endpoint in the /me group that requires enrollment, and it says so itself rather than relying on the group. The group deliberately does not: GET / and POST /enrollment are how a client discovers it needs to enroll and then does so, and gating those on enrollment would make enrollment unreachable. Adding the stricter policy to this route alone means an unenrolled caller is told "enrollment-required" by the authorization handler rather than getting a 400 about the shape of a request that was fine. Idempotent on the public key, and 200 rather than 201 for the reason enrollment gives: a retry of an identical request returns the same body, so there is no single moment of creation to point a Location header at. A second row for one key would mean a device list with a duplicate in it and two wraps to revoke instead of one. Mutation tested — removing the lookup fails RegisterDevice_TwiceWithTheSameKey_ReturnsTheSameDeviceAndAddsNoSecondWrap and nothing else. That test also found a real defect, in the way these usually surface: two timestamps that print identically and are not equal. TimeProvider reports 100-nanosecond ticks and PostgreSQL's timestamp with time zone keeps microseconds, so the first call returned a value that no later read of the row would ever produce, and the idempotent retry answered with a different timestamp for the same device. Nothing breaks, which is what makes it worth fixing: the service now truncates to the precision the column actually holds, so the response is the same value every time it is asked for. The repo already had a precedent for this class of thing in KeyLogChain.TruncateTimestamp; it just had not been applied here. The platform is deliberately not carried on the wire, which leaves Device.Platform unreported and the stale comment corrected rather than fulfilled. It would be a display-only field, and a Contracts enum mirroring the domain's DevicePlatform is exactly the shape of duplication that has produced three self-consistent bugs in this repository. A device list that wants it can add a mapping table and a test pinning the two together, which is what the sync entity types already do. Its own problem code and exception rather than reusing enrollment's, whose rules it largely shares. Registering a device is not enrolling, and a client showing "your enrollment was rejected" because somebody set up a fingerprint reader would be describing the wrong thing. The validation shares the limit constants — MaximumWrapBytes, MaximumDeviceNameLength, PublicKeySize — and not the four-line guards, which would have had to be parameterised over which exception to throw for less than they cost. Both in-memory fakes implement it properly rather than throwing: they record the wrap so a test can assert it arrived, and refuse before enrollment as the real endpoint's policy does. A fake that answered where the server refuses is a fake that can make a real bug pass. 866 tests green, 8 of them new. Zero warnings, dotnet format clean. Still to come: the protector seam with the wrap cached locally so device unlock works offline, then the Windows Hello implementation and the unlock-screen UI — which is where the Windows target framework lands and where automated testing stops. |
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jaap-jan
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a628762cd1 |
Add /me and enrollment with the identity-provider key binding (M1)
The last backend piece of M1. A client can now log in, discover it must enroll, publish its identity key, and get a usable personal vault. Enrollment is one indivisible act. One transaction writes the key, its wraps, the device, the key log entry, the vault and the vault key grant, because none of them is useful alone: a key with no vault leaves a user unable to store anything, and a vault with no grant is a container nobody can ever open -- including its owner, since only the client can wrap the key and it has already moved on. Two independent checks run, and neither substitutes for the other. The Ed25519 self-signature proves possession of the private key. The identity-provider binding proves whose key it is: the client hashed its statement, used the hash as an OIDC nonce, and the resulting ID token is the provider's signature over exactly those public keys. This server cannot mint that signature, so it cannot invent a key for a user who never enrolled -- which is the attack that would otherwise let an operator read every vault by publishing its own key as yours. The binding token is stored verbatim, not just summarised. Clients must repeat the check against the provider's JWKS fetched directly, and storing only our conclusion would ask them to trust the server about the one question the design exists to avoid trusting it about. Key log appends take a deployment-wide advisory lock. The falsification matters more than the passing test: with the lock removed, Enroll_ConcurrentEnrollmentsByDifferentUsers_LeaveAnUnbrokenChain fails with entry 11 linked to the wrong predecessor. Different users trip no unique index, so without serialising they all read the same head and the chain forks -- indistinguishable from the key substitution the log exists to make detectable, and permanent, because the log is append-only. Enrollment is idempotent. Vault ids and keys are client-chosen, so a client whose response was lost re-sends the identical body and gets the identical result. Without that, a lost response leaves a user enrolled against a vault they never learned the id of. Contract change, breaking the v0.1 freeze deliberately. EnrollmentRequest had DevicePublicKey but no wrap to go with it, which is unsatisfiable: only the holder of the secret bundle can seal it, so the server could never fill the gap. Added DeviceWrappedPrivateKey, and PersonalVault so enrollment can be atomic rather than leaving an unopenable vault behind two endpoints that do not exist yet. No client exists and no package is published, which is exactly when PublicAPI.Unshipped.txt expects this. Sync now requires the Enrolled policy, which until now was a stub whose name promised a check it never made. The sync denial tests use enrolled intruders instead of unenrolled ones -- an unenrolled caller is stopped before the vault check runs, which would have left those tests passing without exercising the thing they exist to prove. Also fixed: omitting kdfParameters from the JSON body was a 500. A record's non-nullable parameters are a compile-time promise, not a runtime one. 268 tests pass, zero warnings on a clean rebuild, format clean. |