281f84908624d18e1bd4505ea1e85aebea3ca842
4
Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
 jaap-jan
|
890a5f2246 |
Give the desktop a macOS head, signed from the first release
The same application, the same Velopack and the same two-phase person-run release as Windows, with four things forced to differ. Signing is a precondition rather than an improvement: Gatekeeper refuses an un-notarized download outright instead of warning about it, so there was never the "unsigned for now" that ADR 0013 decision 8 argues for on Windows, and release-macos.sh refuses to start without the identities. The packaging split is narrower than it first looked, and the old claim at the foot of ci.yml is why it was worth checking rather than assuming. vpk cross-compiles when told to: 'vpk [osx] bundle' builds a real .app on any platform, and CI now publishes osx-arm64 and bundles it on every main and tag build, which is what catches a restore graph with no macOS native asset. There is no '[osx] pack' off a Mac, and that part is correct — pack drives codesign, notarytool and stapler, which exist nowhere else. The dylib signing loop in the script looks redundant beside vpk's own pass and is not. vpk signs with 'codesign --deep', which is the shape Apple documents as wrong for nested code, and platform-flags has recorded a notarization rejection that names no file since before any of this existed. Signing each native binary inside-out first leaves that pass nothing to get wrong. MacDeviceKeyStore reaches ADR 0007's conclusion through different hardware: a P-256 key in the Secure Enclave under an access control requiring user presence, so the platform enforces the gate rather than this process — which is the whole point of that ADR's amendment. The enclave holds no other kind of key, hence ECIES where Windows uses RSA-OAEP, and the shape that falls out is better than the Windows one: sealing needs only the public half and is silent, so only unlock prompts. IsSupported probes rather than infers, because three ordinary Macs answer no — an Intel machine without a T2, one with no login password, and every unsigned development build, since enclave keys need a signing identity. Two decisions worth stating because they are reversible. arm64 only: a second channel is small work and nobody here has an Intel Mac to walk Phase 18 on, and an x64 package would be the only artefact in this repository reaching users unverified. And the pack id stays DodoSSH.Desktop even though vpk names the bundle after it, so /Applications holds DodoSSH.Desktop.app: decision 2's reasoning binds harder here, because a pack id of DodoSSH would put Velopack's install root on top of ClientPaths.DataDirectory and let an uninstall take the user's un-synced outbox with it. CFBundleDisplayName puts the product name back in front of a person. Measured rather than assumed, since none of it is obvious: the publish and the bundle were both run, LSMinimumSystemVersion is 12.0 because that is the minos in the apphost's own LC_BUILD_VERSION, and vpk copies a custom Info.plist verbatim with no substitution at all — which is why the plist is a template the script renders and not a committed file. What is not done is the half that needs the hardware. There is no macOS runner, so nothing past "it bundles" has ever run. Phase 18 is the whole of the verification, and the two checks most likely to fail are the terminal against WKWebView and the enclave interop, neither of which has executed once. |
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|
jaap-jan
|
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
|
573f5d5668 |
Keep the device key in the TPM, behind a consent Windows enforces
The last of ADR 0007's three pieces, and it does not implement what that ADR originally decided — because writing it exposed a flaw in the decision. The ADR said "a Windows Hello gesture gating a protected blob". That does not deliver what the rest of the document claims for it: a gate inside the process is not a gate. A store that showed a prompt and then read a DPAPI blob would be bypassed by malware that skipped the prompt, read the file and called CryptUnprotectData itself — which is exactly the attacker the whole decision was made against, and exactly the reason DPAPI alone was rejected. The presence requirement has to be a condition of using the key, enforced below the application, or it is decoration. So the device key is encrypted to an RSA key created in the Microsoft Platform Crypto Provider — the TPM — under CngUIProtectionLevels.ProtectKey. Windows requires consent to use that key, so the prompt is not something this code can be talked out of showing. Malware can ask for the key; it cannot answer the dialog. That is strictly stronger than the ADR described, and most of what option D was being saved for: the wrapping key genuinely never leaves hardware. The X25519 device key still lands in memory to open the wrap, because DSH1 fixes that wrap at a curve the TPM cannot do — the remaining gap, and now a smaller step than it was. CngKey is in-box, so this needed no WinRT projection and no Windows target framework. Which is worth stating plainly because the opposite was planned: the piece was scoped as "where the Windows TFM lands", and it turned out a platform guard on one class was enough. Client.App and its two test projects stay on net10.0. Two things were measured on real hardware rather than assumed, and the second changed the shape of the work. The platform provider works here and holds an RSA key — confirmed by creating and deleting one before writing anything that depended on it. And ProtectKey prompts at key *creation*, not only at use. The comment in the first draft of this file said the opposite, with a confident explanation: sealing uses only the public half, so it should be silent. It is not. CngKey.Create blocks on a dialog, because the policy means "protect this key with a PIN" and Windows asks the user to set that up there and then. Found by writing tests around save and forget and watching the suite hang for ten minutes waiting for somebody to type one. That has two consequences worth knowing before touching this file. SaveAsync is user-facing code — it belongs on a UI thread, behind a button somebody pressed, never on a background pass. And almost nothing in the store can be covered automatically: two tests remain, availability and the empty-blob case, both of which provably reach no dialog. Disabling the UI policy to make the rest testable would remove the one property worth having. The interface offers two things and hides both where they cannot work. "Use Windows Hello" appears on the unlock screen only when this machine has a cached wrap and a keystore still willing to release the key; "Use Windows Hello here" appears in the account bar only when the machine can keep a key and has not already registered one, so it is spent once used. Absent rather than disabled, in both cases: a greyed-out button on a machine that never had a TPM reads as something broken, and the passphrase box beside it is not a fallback — it is the ordinary way in. Both unlock paths now share AdoptAsync rather than each opening the known-host store, building the vault and starting auto-sync. The ordering in there is load-bearing and a second copy would be a second chance to get it wrong. The shell's tests drive a fake keystore. Not for speed: the real one prompts on every save and load, so a suite using it would block forever. What the shell has to get right is which buttons appear and what happens when one is pressed, and a fake answers exactly that. It is shared from Client.Session.Tests by source link rather than reimplemented. 882 tests green, 6 of them new. Zero warnings, dotnet format clean. Not verified, and not verifiable here: the dialogs. Whether the consent prompt appears at the right moments, reads sensibly, and returns to a usable window when declined needs the application run by a person on a machine with a TPM. That is the remaining half of outstanding item #7, and it is now the only thing between this feature and being finished. |
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|
jaap-jan
|
7016ce36f1 |
Key the local cache to the identity, not to the door it was opened through
Groundwork for a device key, and a spec change rather than a feature. ADR 0007 records the decision it clears the way for: a Windows Hello gesture guarding a protected blob, with the passphrase kept as a permanent fallback. The reason that decision needed this first is that a device key cannot open a session on its own. SessionOpener derived two things from the passphrase master key — the bundle, and the local cache key — and a device wrap is SealTo(device_x25519_pk), which yields the bundle and never computes a master key at all. A device unlock could therefore have opened the identity and still not read the cache it had itself written. So LocalCacheKey now derives from the bundle: dsh1/localcache/v1 → v2, specified in crypto.md §3.2. Every wrap that opens a vault ends up holding the bundle, so every door reaches the same cache. Extract-and-expand, not expand alone. Everything derived from the master key uses HKDF-Expand directly, which is sound because an Argon2id output is uniformly random over its whole length. The bundle's encoding is not — it opens with a fixed 14-byte label and carries a version, a generation and a timestamp before reaching any key material — so it needs the extract step to become a pseudorandom key first. Two consequences fell out, both improvements and neither the point: - A passphrase change no longer discards the local cache. The bundle is unchanged by a re-wrap, so the cache key is too. Under v1 changing a passphrase silently orphaned every cached row and the next launch re-pulled the whole vault. - Recovery-code unlock is fixed before it ships. It derives a different master key from a different secret and a different salt, so under v1 it would have had the same defect as the device path, and nobody would have noticed until it landed. The cache becomes unreadable exactly when the identity is rotated, which is the correct moment to discard it. Existing caches are discarded and re-pulled on upgrade — already the specified behaviour for a stale cache, and the reason the label is versioned rather than reused: a v1 cache must fail to open rather than decrypt to nonsense. One stated guarantee got weaker and now says so. crypto.md §10 claimed locking meant "nothing on disk can be read again without the passphrase." Where a device wrap exists that is no longer true, and it would have been untrue under either candidate design — the alternative was storing a copy of the cache key in the device blob, which is the same door with an extra key lying next to it. The wording now points at ADR 0007, because what guards the device key is a platform decision and not a property of this specification. A golden vector was quietly lying, which is the part worth reading twice. The "local-cache" entry pinned HKDF-SHA512-Expand over a fixed PRK — a construction the cache key no longer uses. Regenerating it would have produced a green suite describing a derivation this code does not perform. It is replaced by a vector over a bundle whose every byte is pinned: the label, version 1, generation 1, a fixed timestamp and two recognisable key scalars, all visible in the fixture so a second implementation can check itself against it. UserSecretBundle.TryDecode is internal for this, because Create draws fresh randomness and so can never produce a reproducible input. Mutation tested, and this one earns its keep: dropping the extract step now fails CommittedVectors_MatchCurrentImplementation. The vector it replaced could not have caught that, because it never touched the bundle at all. One test became false and says so. ARecordSealedUnderAnotherPassphrase is now ARecordSealedByAnotherIdentity: a different passphrase deliberately no longer changes the cache key, and TheLocalCacheKey_SurvivesAPassphraseChange pins that. What must still be unreadable is another user's cache. CacheHarness therefore generates an identity rather than deriving from a passphrase, and has no passphrase parameter left — the cache key is not a question about passphrases any more. SyncHarness's two simulated machines now derive the same cache key, which is what keying on the bundle means: they are the same user holding the same identity. They still have separate cache databases, so nothing is shared between them but the key that would open either. Both harnesses lost a MasterKey field that existed only to make a protector. 858 tests green. Zero warnings, dotnet format clean. Not done: the device key itself. Three pieces remain, and the middle one was a discovery rather than a plan — EnrollmentService.AddDevice runs only during enrollment, so every already-enrolled account, which is all of them, needs an endpoint to add a device wrap while unlocked. The client proves possession by producing the wrap, so that shape falls out of the crypto. After that: the protector seam with the wrap cached locally for offline unlock, then the Hello implementation and the unlock-screen UI, which is where the Windows TFM lands and where automated testing stops. |