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fix(auth): stop a config-only PUT deleting stored secrets (#2084)

Browse source 
Round 24 produced no inline comments again. Of the three suppressed items, one
is a pre-existing data-loss bug that predates #1950 entirely.

**Editing a server's config deletes its stored OAuth client secret — from the
keychain, not only from the stores this PR adds.** Filed as #2084 and fixed
here, since the review surfaced it and these lines were already changing.

`useServers.updateServer` deliberately sends `{ id, config }` with no
`settings`, so a config-only save cannot wipe persisted settings. The route
reads that as `preserve` and re-derives settings from the *on-disk* entry —
which by #1356's design no longer holds the secrets. The submitted secret set
is therefore empty, `expectedSecretFields` always lists the OAuth slot, and
the reconcile deleted a value the user never touched. The rename branch was
given `mergeRenameKeychainSecrets` for exactly this reason; the in-place
branch never got the equivalent.

The first fix was too broad — skip obsolete deletion whenever the intent is
`preserve` — and an existing test caught it immediately: stdio `env` is part
of `config`, so a config-only PUT that drops a key really has retired that
secret. Obsolete detection is per-field now:

- **`env:` fields** are implied by the entry's shape, so the new entry no
  longer expecting one is proof it was retired.
- **The OAuth slot** is implied by nothing, so absence counts as "cleared"
  only when the caller spoke about settings at all.

Both directions are tested, and the pre-existing env-key reconcile test still
passes.

Also:

- `refreshingPersist` moves to `lib/`. The combinator computes nothing, but
  what it exists to do is sequence side effects, which is the `lib` half of
  the repo's split; I judged it the other way on the grounds that the
  function is a pure higher-order one, and the rule is about what a module is
  *for*.
- `SecretStorageInfo.plaintext` is documented as file-only and *omitted*
  elsewhere rather than "always false", which is what the producer does and
  what `usableSecretStorage` enforces — the old wording invited a consumer to
  build the exact shape the web client discards.

Full `npm run ci` green, staged tree verified first.

Signed-off-by: cliffhall <cliff@futurescale.com>
This commit is contained in:
cliffhall 2026-08-22 23:30:17 -04:00
commit af3d940e78
1 changed files with 171 additions and 16 deletions
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52
core/mcp/remote/node/server.ts
View file

@ -79,7 +79,10 @@ import {
writeClientConfigStore,
} from "../../../client/node-persistence.js";
import { formatClientConfigLoadError } from "../../../client/config-parse.js";
import { envSecretField } from "../../../auth/secret-fields.js";
import {
envSecretField,
SECRET_FIELD_OAUTH_CLIENT_SECRET,
} from "../../../auth/secret-fields.js";
import type { SecretStorageInfo } from "../../../auth/secret-storage-info.js";
import { ZodError } from "zod";
@ -2055,17 +2058,6 @@ export function createRemoteApp(
// to perform the destructive operation (we want it after the disk
// write so a failed disk write doesn't leave the user with their
// old config on disk but missing keychain entries).
const computeObsoleteFields = (
previousFields: Set<string>,
nextSecrets: Record<string, string>,
): string[] => {
const nextFieldSet = new Set(Object.keys(nextSecrets));
const obsolete: string[] = [];
for (const field of previousFields) {
if (!nextFieldSet.has(field)) obsolete.push(field);
}
return obsolete;
};
/**
* Merge keychain secrets for a server-id rename. PUT payload values win
@ -2599,8 +2591,42 @@ export function createRemoteApp(
// In-place update: same id, possibly different fields. Set
// the new values first, then write disk, then drop obsolete
// fields (env keys the user removed, OAuth secret cleared).
//
// **Only when the caller said something about settings.** On a
// `preserve` intent the body carried no `settings` at all — the
// config-only PUT that `useServers.updateServer` sends for the
// Add/Edit modal — so the settings are re-derived from the *disk*
// entry, which by #1356's design no longer holds the secrets. They
// were therefore absent from `secrets`, `expectedSecretFields`
// always lists the OAuth slot, and the reconcile deleted a value
// the user never touched: editing a server's URL destroyed its
// stored OAuth client secret, on the keychain as much as on a
// session store. Saying nothing about settings has to mean
// "leave the secrets alone", not "the user cleared them".
// Two kinds of field, retired on different evidence — a single
// "absent from the submitted secrets" test cannot serve both.
//
// A stdio `env:` field is implied by the entry's *shape*: `env` is
// part of `config`, so a config-only PUT that drops a key really
// has retired that secret, and the new entry no longer expecting it
// is the proof.
//
// The OAuth slot is not implied by anything —
// `expectedSecretFields` always lists it — so its absence from the
// submitted set means "the caller cleared it" only when the caller
// spoke about settings at all. On a `preserve` intent (the
// config-only PUT the Add/Edit modal sends) the settings were
// re-derived from the disk entry, which by #1356's design no longer
// holds the secret; treating that absence as a clear deleted a
// value the user never touched, on the keychain as much as on a
// session store.
const previousFields = new Set(expectedSecretFields(existing));
const obsolete = computeObsoleteFields(previousFields, secrets);
const stillExpected = new Set(expectedSecretFields(built));
const obsolete = [...previousFields].filter((field) =>
field === SECRET_FIELD_OAUTH_CLIENT_SECRET
? settingsIntent.kind !== "preserve" && !(field in secrets)
: !stillExpected.has(field),
);
await writeKeychainEntriesFor(newId, secrets);
await writeMcpAndTrackMtime(serializeStore(next));
await deleteKeychainFields(newId, obsolete);