mirror of
https://github.com/kuhyx/testsAndMisc.git
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Krzysztof kuhy Rudnicki
82e206116a
The enforcer failed in both directions: nothing blocked at home, and everything blocked at the office. The comparison was never inverted -- `metres <= threshold` was always right. Three separate causes: Only ACCESS_COARSE_LOCATION was declared. Android 12+ fuzzes coarse to a ~1-2 km grid against a 150 m fence, so a fix taken at home routinely landed outside it, read as AWAY, and restored every app the geofence exists to hide. FINE is now declared and self-granted by the device owner, along with coarse and background, re-asserted every pass so a reinstall cannot silently drop it. There were three states but two behaviours. LOCATION_UNKNOWN applies the identical sweep to AT_HOME -- correct fail-closed design, indistinguishable from outside. And nothing ever requested a fix: the pass read whatever another app happened to cache, so at the office with no navigation running the cache was empty. Passes now acquire a fix inside a location-typed foreground service, bounded at 20 s, and treat anything older than 30 min as no fix. That window is deliberately longer than the 15-minute cadence; a shorter one marks the newest cache stale on every pass of an idle phone and blocks everything. None of it was diagnosable. `adb logcat -d -s FocusOwner:V` came back empty while dumpsys showed 82 alarms had fired, and `run-as` is refused on the release build device owner requires. So the pass now writes a ring-buffered JSONL record read back in-app: reason, distance vs the fence, fix age/provider/accuracy, curfew state, and every hidden app with the rule that hid it. Coordinates are never recorded -- a distance is enough to debug a geofence, and this is a home address. Also fixed along the way: - Hysteresis keyed off `isEnforcing`, which is true under AWAY too because YouTube stays hidden, so the threshold was permanently radius+hysteresis. It now keys off whether the previous pass was inside the fence. - The scheduler's curfew-boundary alarms were documented but never scheduled; both callers invoked `scheduleNext()` bare, so 05:00 could land 15 min late. - Installing over the app cancelled its pending alarms, so `adb install -r` silently stopped enforcement until someone opened the app. MY_PACKAGE_REPLACED now re-arms it, verified on device without launching the app. - A wrong-typed log record threw instead of being skipped, and the exception escaped far enough to leave the page stuck busy -- which disables the release-device-owner button, the one control that must work when everything else has gone wrong. - `lib/enforcement.dart` was a second decision layer with no always-blocked concept, cited by KDoc as pinned by a `PolicyParityTest` that never existed. It would have made the new screen report YouTube visible while it is hidden. Deleted; the UI renders the Kotlin record rather than re-deciding. - Anchoring home accepted a stale or unknown-precision fix. A wrong home offsets the fence everywhere and forever, which is what produced a 766 m reading while standing at home. Policy: Play Store is allowed by day (not during curfew) so infakt can be installed and updated; the sweep is default-deny for third-party packages, so anything installed from Play is hidden on the next at-home pass. Tachiyomi's per-source extension apks are covered by a new prefix allowlist rather than an exact list that goes stale whenever an extension is installed. `export.py` stopped subtracting the allowlist from `blockable_system_packages`. Sweepable is not hideable: that list decides which system packages are eligible for a decision, and `isAllowed` is what protects them. Removing an allowed system package from the sweep freezes it in its last state -- it would have stranded Play hidden permanently the moment it was allowlisted. Verified on the Pixel 6a: FINE granted POLICY_FIXED, `applied AT_HOME` with a 0 m distance from a +/-11 m GPS fix, YouTube/Chrome/Firefox absent from `pm list packages -e`, Play Store, infakt, RunnerUp and all five Tachiyomi packages present. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01HjxL9kdAzZmGqQA5tMNrZ8
143 lines
7.1 KiB
Markdown
143 lines
7.1 KiB
Markdown
# focus_owner
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Device Owner app that enforces focus mode on an unrooted Pixel 6a
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(`23181JEGR08034`). It hides apps by GPS distance from home, plus a 23:00–05:00
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night curfew, and keeps YouTube hidden everywhere.
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**Live and enforcing.** It is provisioned as device owner, pins RethinkDNS as an
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always-on VPN with lockdown, and blocks its own uninstall while enforcing.
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## How a decision is made
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One pass runs every 15 minutes (and at each curfew boundary), from
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`EnforcementService` → `EnforcementRunner.decide()` → `EnforcementDecision.evaluate()`.
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There are **five** outcomes, and only the first two look different from the
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outside — which is exactly what made this hard to debug before the status
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screen existed:
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| Reason | What it does |
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| ------------------ | ----------------------------------------------------------------------------------- |
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| `AWAY` | Hides only `always_blocked_packages`; everything else is available. |
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| `AT_HOME` | Full day allowlist sweep. |
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| `CURFEW` | Full sweep against the shorter night allowlist. |
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| `LOCATION_UNKNOWN` | **Identical sweep to `AT_HOME`** — fail-closed, so losing GPS is not an off switch. |
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| `WORKOUT` | As at home, plus the workout exemptions. |
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Plus a sixth state that is not a reason: **no home configured**, which makes the
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fence answer "inside" everywhere and so enforces everywhere. The status screen
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renders that case explicitly rather than letting it read as `AT_HOME`.
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`always_blocked_packages` (YouTube, YouTube Music, Chrome) are exempt from every
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branch including `AWAY` and `WORKOUT`, so leaving the house cannot restore them.
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## Diagnosing it
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**Use the in-app screen, not adb.** Neither adb route works here:
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- `run-as` returns `package not debuggable` — device owner requires a release
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build, and making it debuggable would let anyone with adb edit this app's
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state, which is the bypass the whole design exists to close.
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- logcat rotates. Measured 2026-08-14: `adb logcat -d -s FocusOwner:V` came back
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**empty** while `dumpsys alarm` showed 82 alarms had fired.
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So the durable record is `filesDir/enforcement_log.jsonl`, written by
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`EnforcementLog` and read back over the platform channel. The main screen shows
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the latest pass — reason, distance vs the fence, fix age/provider/accuracy,
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curfew state, and every hidden app with the rule that hid it — and **Debug log**
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shows the history. It never records coordinates: distance in metres is enough to
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debug a geofence, and this is a home address.
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Useful fields when something looks wrong:
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- `fix.outcome` — `CACHED_FRESH` / `ACTIVE_OK` / `TIMEOUT` / `NO_PERMISSION` /
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`NO_PROVIDER`. Distinguishes "no fix at the office" from "fuzzed fix at home".
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- `fix.accuracy_m` — tens of metres means precise location is live. Hundreds or
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thousands means the app is being fed fuzzed coarse location and the 150 m
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fence cannot be trusted.
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- `failure` — set on passes that decided nothing (not provisioned, unreadable
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policy), which otherwise leave no trace at all.
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## Location
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The geofence needs `ACCESS_FINE_LOCATION`; coarse is fuzzed to a ~1–2 km grid on
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Android 12+, against a 150 m radius. The app **self-grants** fine, coarse and
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background location every pass via `setPermissionGrantState` (device owner needs
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no prompt), and calls `setLocationEnabled(true)`.
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Each pass actively requests a fix rather than reading whatever another app
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cached, bounded by `ACQUIRE_TIMEOUT_MS` (20 s) and run inside a
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`location`-typed foreground service — background location delivery is throttled
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too hard otherwise. A cached fix younger than `FRESH_WINDOW_MS` (30 min) is used
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as-is; anything older is treated as no fix and fails closed. That window is
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deliberately **longer than the 15-minute cadence**: a shorter one would mark the
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newest available cache stale on every pass of an idle phone and block everything.
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## Policy
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Generated from `phone_focus_mode/config.sh`, never hand-edited:
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```bash
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cd ~/testsAndMisc
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python3 -m python_pkg.focus_policy \
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--config phone_focus_mode/config.sh \
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--output focus_owner/assets/policy.json --redact-home
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```
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`--redact-home` is required — the committed asset must keep `latitude`/
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`longitude` null. Real coordinates live only in app-private storage, written by
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"Set home to current location" in the app.
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Allowlists are exact-match, plus `allowed_prefixes` / `night_allowed_prefixes`
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for apps that ship as a package family (Tachiyomi installs every source as its
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own apk). Prefixes match whole labels, so `eu.kanade.tachiyomi` covers
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`eu.kanade.tachiyomi.extension.all.mangadex` but not `eu.kanade.tachiyomisomething`.
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**Sweepable is not the same as hideable.** `blockable_system_packages` decides
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which `FLAG_SYSTEM` packages are _eligible for a decision_; `isAllowed` is what
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then protects them. Removing an allowed system package from that list does not
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protect it, it **freezes** it in whatever state it was last left in — it lands
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in neither `packagesToHide` nor `packagesToShow`. Play Store is the live example.
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## Build and verify
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```bash
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cd ~/testsAndMisc/focus_owner
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flutter analyze && flutter test
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JAVA_HOME=/usr/lib/jvm/java-21-openjdk (cd android && ./gradlew :app:testDebugUnitTest)
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JAVA_HOME=/usr/lib/jvm/java-21-openjdk flutter build apk --release
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adb -s 23181JEGR08034 install -r build/app/outputs/flutter-apk/app-release.apk
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adb -s 23181JEGR08034 shell am start -n com.kuhy.focus_owner/.MainActivity
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```
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`JAVA_HOME` is required: the system default JDK 26 breaks the Android Gradle
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plugin's `jlink` transform.
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Release build only — device owner refuses a debuggable one. Then tap **Run
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enforcement now** and read the status card; `EnforcementService` is not
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exported, so it cannot be started from adb.
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> **Never** `adb uninstall`, `pm clear`, or wipe this app's data. Uninstalling a
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> device owner strands ownership with no holder and a factory reset becomes the
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> only exit. `install -r` is safe and preserves the home location.
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## Why the escape hatch ships first
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`dpm remove-active-admin` does not work on a device owner. The only exit that
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avoids a factory reset is `DevicePolicyManager.clearDeviceOwnerApp()`, callable
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solely by this package on itself. So `releaseDeviceOwner()` is implemented,
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unit-tested, and reachable from the main screen with no PC attached.
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Accounts now exist on the device, so `dpm set-device-owner` would refuse to run
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again: releasing is a one-way door until a wipe. The confirmation dialog says so
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in those terms. See
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`~/.claude/projects/-home-kuhy-testsAndMisc/memory/device-owner-not-root-banking-works.md`.
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## Known gap
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The network layer does not filter `youtube.com`. `private_dns_host` is empty
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(the router does not forward 853, and under VPN lockdown app DNS goes to the
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VPN's own resolver anyway), and RethinkDNS's blocklists can be switched off from
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inside that app. So a browser reaches YouTube on the web **when away from home**.
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At home and during curfew every browser is hidden, which is what closes it there.
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