Apply store-paired device_id to per-ghost crypto clients (kill SigningKeyChanged churn) #35

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opened 2026-06-19 17:01:58 +00:00 by robocub · 2 comments

robocub commented

2026-06-19 17:01:58 +00:00

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Follow-up from the #30 fix (84b0a0c).

The per-ghost crypto clients (crates/matrix-rtc/src/rtc/ghost.rs::build_ghost_crypto_client) use a stable device_id of D<discord_user_id> — the same reuse-with-new-keys pattern that broke the bot subscriber on a fresh store in #30.

Impact: does not break audio (ghosts are senders — they Olm-encrypt to the humans' own stable devices), but on a fresh/changed store it produces the Rejecting device update ... SigningKeyChanged log churn at startup.
Fix: apply the same store-paired-device-id approach used for the bot in #30 (matrix.rs::resolve_store_device_id) to each per-ghost store dir, so ghost identities stay consistent across wipes and the churn disappears.
Priority: low / cleanup.

Follow-up from the #30 fix (`84b0a0c`). The per-ghost crypto clients (`crates/matrix-rtc/src/rtc/ghost.rs::build_ghost_crypto_client`) use a stable `device_id` of `D<discord_user_id>` — the **same reuse-with-new-keys pattern** that broke the bot subscriber on a fresh store in #30. - **Impact:** does **not** break audio (ghosts are senders — they Olm-encrypt to the humans' own stable devices), but on a fresh/changed store it produces the `Rejecting device update ... SigningKeyChanged` log churn at startup. - **Fix:** apply the same store-paired-device-id approach used for the bot in #30 (`matrix.rs::resolve_store_device_id`) to each per-ghost store dir, so ghost identities stay consistent across wipes and the churn disappears. - **Priority:** low / cleanup.

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2026-06-19 17:01:58 +00:00

robocub referenced this issue

2026-07-03 00:30:50 +00:00

Ghost to-device receive path / Olm wedge self-heal #52

robocub commented

2026-07-03 00:31:10 +00:00

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Related to the wedge in #52 / #34. Minting a fresh crypto device every ghost lifecycle (post-#44 in-memory design) is a primary driver of the stale-device pile-up that wedges listener Olm sessions. Stabilizing the ghost crypto identity keeps device lists clean and lets a listener's session persist across restarts. Note the tension with #44 (storeless/in-memory = SigningKeyChanged-safe via fresh device): stabilizing needs a light account-persistence approach (pickle/restore, not a held per-ghost SQLite deadpool — that was #44's FD killer). #34 (prune-on-startup) fixes the observed silence even with churn, so this is the secondary/optimization half.

**Related to the wedge in #52 / #34.** Minting a fresh crypto device every ghost lifecycle (post-#44 in-memory design) is a primary driver of the stale-device pile-up that wedges listener Olm sessions. Stabilizing the ghost crypto identity keeps device lists clean and lets a listener's session persist across restarts. Note the tension with #44 (storeless/in-memory = `SigningKeyChanged`-safe via fresh device): stabilizing needs a *light* account-persistence approach (pickle/restore, not a held per-ghost SQLite deadpool — that was #44's FD killer). #34 (prune-on-startup) fixes the observed silence even with churn, so this is the secondary/optimization half.

robocub referenced this issue

2026-07-03 00:44:21 +00:00

Prune stale superseded bot devices on the homeserver after a fresh-store wipe #34

robocub referenced this issue from a commit

2026-07-03 02:47:06 +00:00

fix(matrix-rtc): stable ghost media-key delivery — rejoin re-key (#51) + persistent identity (#35)

robocub referenced this issue

2026-07-03 21:38:25 +00:00

Startup self-prune of stale bridge/ghost devices (device hygiene automation) #53

robocub commented

2026-07-05 15:31:36 +00:00

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Shipped in v0.3.0-alpha.2 (master 1bf9723). Ghost crypto device ids now fold in a per-store salt → D<key>-<salt> (resolve_ghost_device_salt), pairing the ghost device identity with its crypto store exactly like the bot's minted id from the #30 fix (resolve_store_device_id). A wiped/copied/second store re-provisions a brand-new device instead of presenting the old id with new Olm keys, so peers never hit SigningKeyChanged; the per-lifecycle device churn this issue describes is gone.

This also turned out to be load-bearing beyond cosmetics: stable ghost identities stop the stale-device pile-up that was poisoning listener device lists and draining OTKs (the #34/#52 wedge chain).

Live-verified in prod: across the alpha.3→alpha.7 deploys, all ghost/bot device ids report reused=true and encrypted calls re-key in seconds. Closing.

**Shipped in v0.3.0-alpha.2** (master `1bf9723`). Ghost crypto device ids now fold in a **per-store salt** → `D<key>-<salt>` (`resolve_ghost_device_salt`), pairing the ghost device identity with its crypto store exactly like the bot's minted id from the #30 fix (`resolve_store_device_id`). A wiped/copied/second store re-provisions a brand-new device instead of presenting the old id with new Olm keys, so peers never hit `SigningKeyChanged`; the per-lifecycle device churn this issue describes is gone. This also turned out to be load-bearing beyond cosmetics: stable ghost identities stop the stale-device pile-up that was poisoning listener device lists and draining OTKs (the #34/#52 wedge chain). Live-verified in prod: across the alpha.3→alpha.7 deploys, all ghost/bot device ids report `reused=true` and encrypted calls re-key in seconds. Closing.

robocub closed this issue

2026-07-05 15:31:36 +00:00