2 Commits

Include renames

Author	SHA1	Message	Date
jaap-jan	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.	2026-08-03 23:05:40 +02:00
jaap-janandClaude Opus 5	a43286ece8	Let a team change hands, and be joined by somebody with no account yet ... M3 built teams and stopped short of the two operations that decide who controls one. Both were written down as refusals rather than omissions: ADR 0009 listed ownership transfer under "deliberately not built", and design-import-gaps said an invitation needed "a token with a lifetime and an outbound mail path". One of those reasons had expired and the other never applied — an invitation does not need a token if it is not a thing anybody presents. Handing a team over is one write. The member you name becomes owner and you become an admin, in a single transaction, because ownership is sole: promoting first leaves the team owned twice, demoting first leaves it owned by nobody, and there is nobody left with the authority to finish a transfer that stopped in the middle. That is also why it is not two calls to the role endpoint, which refuses Owner outright. The outgoing owner is demoted rather than removed — removing them would revoke their vault key grants and flag every team vault for rekey, which is a far larger act than the one asked for, and somebody handing over a team is usually staying in it. It unblocks the thing that was impossible before: an owner can now leave, by handing the team on first. An invitation is a standing instruction rather than a message. This server has no outbound mail path, so nothing is sent and there is nothing for the invitee to present. The row says the next account signing in with that address joins this team at this role, and telling them to sign in is the caller's job over a channel this server does not carry. A link nobody can deliver would be worse than none. It lives in its own table rather than becoming a membership with MembershipStatus.Invited, and that member stays unwritten for the reason it always was: team_membership.user_id is not nullable and carries a foreign key, so somebody who has never signed in has nothing for that row to point at. Widening it would make the unique index on (team, user) meaningless, because PostgreSQL counts every NULL as distinct. Verification is the security boundary, and nothing in this server read it before. A claim requires the access token to assert email_verified. An invitation decides what the server will serve, so one claimable by anybody able to obtain a token carrying somebody else's address is a way into a team — which is precisely the attack OidcOptions.AllowEmailLinking exists to refuse, and it would have been reintroduced by the back door. There is deliberately no setting that relaxes it: a flag that exists is one somebody turns on for the afternoon their provider is misconfigured. Absence is refused rather than trusted, and logged, because a provider that never sends the claim otherwise leaves every invitation pending with nothing anywhere saying why. Claiming happens at just-in-time provisioning and again on an hourly sweep. The sweep is what makes it recoverable rather than one-shot — an invitation issued between an account being created and that person next signing in would otherwise be stranded for ever — and it shares its rate with the last-seen write because both are housekeeping nobody is waiting on. Archiving is refused while a team owns a vault, and that refusal is the end of the road rather than a step on it. A team vault is readable because of membership, so archiving one that still owned vaults would take them away from everybody holding a key, including the caller, quietly and all at once. Nothing in this product deletes a vault, so no order of operations gets past it today — which is stated with a count of what is in the way, for the reason the SFTP layer refuses a recursive delete: a refusal is visible and a quiet removal is not. It is owner-only, as handing over is; renaming is not, because a rename is visible to everybody and reversible by anybody who can do it. The slug is not renameable at all: it is unique only among live teams, so a rename could take one an archived team is still holding, and that team could then never be restored. LAST ACTIVE is real and coarse on purpose. UserAccount.LastSeenAtUtc is refreshed on ordinary authenticated requests, at most once per account per hour, through ExecuteUpdateAsync — user_account carries the xmin concurrency token, so a read-then-write on the hot path would start losing races between one user's own overlapping requests. An hour is the granularity the question is actually asked at, and the interface draws it to the day rather than the minute so it does not read as a precision that is not there. The remarks in Contracts and in the view model that argued at length for the column's absence are rewritten rather than extended; both had become false. Two endpoints already existed and nothing called them. ChangeTeamMemberRole and ListVaultGrants have been reachable since M3. The role picker refuses Owner itself rather than letting the server do it, since the interface already knew the rule; the key-holder list sits under the vault rather than beside the member, because a grant is per vault and a count on a member row would imply per-item sharing, which is M5. It lists withdrawn and stale grants and says which they are — a list that dropped them would show a departed colleague as merely absent rather than as somebody whose key was taken away — and staleness is decided by comparing generations, since a grant can be Active and still open nothing. ADD MEMBER stopped being a dead end. An address the directory did not know used to end at a sentence telling the user their colleague had to sign in first. It invites them instead, from the same button, because which of the two applies is a fact about the server's account table rather than about what the user is doing; which one happened is reported afterwards, because that decides what they do next. An address that merely has an account is invited rather than refused: refusing would have made the endpoint an oracle for which addresses have accounts here, answerable by anybody willing to create a team first. The phone has a TEAMS screen, behind MORE, and it is the reverse of every other row in design-import-gaps: a shipped screen the design had no slot for. It is there because an invitation is claimed by signing in, so somebody told they are now in a team is at least as likely to be holding a phone — and a membership visible only on a head they never installed is one they cannot see. It draws SHARE KEY and nothing that takes something away: wrapping a key is the one act on that screen a server cannot perform at all, and the desktop guards its revocations with a tooltip, which is a control a touch screen cannot show. Two defects were found by an adversarial pass and both were green against the whole suite at the time. The owner-only check on archiving and handing over had been weakened to the admin check while their messages and comments still said owner — and since nothing behind the archive endpoint re-checks it, an admin the owner had promoted could have archived the team out from under them. And the rename endpoint built its response with a hardcoded Owner role, so an admin who renamed a team was handed a summary claiming they owned it, and a client trusting that instead of re-listing would have offered them the two owner-only buttons the server then refuses. The new table gets its constraints tested rather than merely migrated: live uniqueness per (team, address), the citext proof that an address typed by a person matches one cased by a provider, and reissue after both revocation and acceptance. The teams screen gets its first entries in the layout suite, at the minimum window with every list populated and with each of the two states that cover half of it — it had none, and it just grew four sections and a second line in the member row. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>	2026-08-03 14:31:43 +02:00